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Sample records for wireless lan wlan

  1. Securing a medical wireless LAN system

    OpenAIRE

    Owens, TJ; Tachakra, S; Banitsas, KA; Istepanian, RSH

    2001-01-01

    Recently the concept of MedLAN systems dedicated to application scenarios for wireless local area networks (WLAN) in hospital A&E departments has been presented. An essential element in the acceptance of the system will be reassuring all stakeholders in the system that data transmitted using the system is secure. In order for the stakeholders to be reassured technical and managerial issues have to be addressed. Technical issues to be addressed include selection of a suitable encryption algori...

  2. Adjusting DICOM specifications when using wireless LANs: The MedLAN example

    OpenAIRE

    Banitsas, KA; Tachakra, S; Song, YH

    2003-01-01

    Wireless networks will become increasingly useful in point-of-care areas such as hospitals, because of their ease of use and their flexibility. A system called MedLAN has been developed by the Central Middlesex Hospital and Brunei University to take advantage of the above desirable properties of WLANs for use in accident & emergency departments to broadcast live, high quality video images and sound over a LAN or the Internet. However, in many cases, the limited available throughput of such a ...

  3. How wireless LANs can enhance the clinical environment.

    Science.gov (United States)

    Riha, Chris

    WLANs deployments in health care institutions offer clinicians opportunities to increase productivity and improve patient care with additional point-of-care access to information systems. However, they are not a panacea. Any data that needs guaranteed reliability and protection for outside interference, such as real-time cardiac monitoring, should be on networks operating in the Wireless Medical Telemetry Service (WMTS) range. The WMTS range, (608-614 MHz, 1395-1400 MHz, and 1429-1432 MHz), was established in 1999 by the FCC as a protected frequency range (in the U.S.) making these products less likely to have interference problems than devices operating in the 802.11 range. Security challenges must also be addressed as each access point is synonymous with installing a RJ45 network jack in the parking lot of a facility and inviting the general public to connect to a network. Also, increased mobility of electronic devices means battery power; thus consideration will need to be given to charging, maintaining, and disposal of batteries. WLANs offer many advantages over conventional wired LANs but they also offer many challenges in addressing security and reliability issues. WLANs are not designed to replace conventional hard-wired network infrastructure; they are designed to augment the connectivity of LANs. Even with the 802.11 g standard, which supports connectivity up to 54 Mbps, large medical image files would not have enough bandwidth on this type of wireless network. Wireless networks can enhance the health care technology infrastructure but proper selection of technology and focus on the security and reliability during the planning and installation is a definite requirement.

  4. Wireless Local Area Network (WLAN) Vulnerability Assessment and Security

    National Research Council Canada - National Science Library

    Kessel, Adam; Goodwin, Shane

    2005-01-01

    The proliferation of wireless computer equipment and Local Area Networks (LANs) create an increasingly common and growing threat to Marine Corps Network infrastructure and communication security (COMSEC...

  5. A New Mechanism for Network Monitoring and Shielding in Wireless LAN

    Directory of Open Access Journals (Sweden)

    Jiujun Cheng

    2014-01-01

    Full Text Available Wireless LAN (WLAN technology is developing rapidly with the help of wireless communication technology and social demand. During the development of WLAN, the security is more and more important, and wireless monitoring and shielding are of prime importance for network security. In this paper, we have explored various security issues of IEEE 802.11 based wireless network and analyzed numerous problems in implementing the wireless monitoring and shielding system. We identify the challenges which monitoring and shielding system needs to be aware of, and then provide a feasible mechanism to avoid those challenges. We implemented an actual wireless LAN monitoring and shielding system on Maemo operating system to monitor wireless network data stream efficiently and solve the security problems of mobile users. More importantly, the system analyzes wireless network protocols efficiently and flexibly, reveals rich information of the IEEE 802.11 protocol such as traffic distribution and different IP connections, and graphically displays later. Moreover, the system running results show that the system has the capability to work stably, and accurately and analyze the wireless protocols efficiently.

  6. Wireless LAN: 802.11b

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Wireless LAN: 802.11b. Replacement for Ethernet. Supported data rates. Current: 11, 5.5, 2, 1 Mbps; Future: 20+ Mbps in 2.4 GHz and up to 54 Mbps in 5.7 GHz band. Range. Indoor 20 - 25 meters; Outdoor: 50 – 100 meters. Transmit power up to 100 mW.

  7. Optimal Modeling of Wireless LANs: A Decision-Making Multiobjective Approach

    Directory of Open Access Journals (Sweden)

    Tomás de Jesús Mateo Sanguino

    2018-01-01

    Full Text Available Communication infrastructure planning is a critical design task that typically requires handling complex concepts on networking aimed at optimizing performance and resources, thus demanding high analytical and problem-solving skills to engineers. To reduce this gap, this paper describes an optimization algorithm—based on evolutionary strategy—created as an aid for decision-making prior to the real deployment of wireless LANs. The developed algorithm allows automating the design process, traditionally handmade by network technicians, in order to save time and cost by improving the WLAN arrangement. To this end, we implemented a multiobjective genetic algorithm (MOGA with the purpose of meeting two simultaneous design objectives, namely, to minimize the number of APs while maximizing the coverage signal over a whole planning area. Such approach provides efficient and scalable solutions closer to the best network design, so that we integrated the developed algorithm into an engineering tool with the goal of modelling the behavior of WLANs in ICT infrastructures. Called WiFiSim, it allows the investigation of various complex issues concerning the design of IEEE 802.11-based WLANs, thereby facilitating design of the study and design and optimal deployment of wireless LANs through complete modelling software. As a result, we comparatively evaluated three target applications considering small, medium, and large scenarios with a previous approach developed, a monoobjective genetic algorithm.

  8. Proposal of Wireless Traffic Control Schemes for Wireless LANs

    Science.gov (United States)

    Hiraguri, Takefumi; Ichikawa, Takeo; Iizuka, Masataka; Kubota, Shuji

    This paper proposes two traffic control schemes to support the communication quality of multimedia streaming services such as VoIP and audio/video over IEEE 802.11 wireless LAN systems. The main features of the proposed scheme are bandwidth control for each flow of the multimedia streaming service and load balancing between access points (APs) of the wireless LAN by using information of data link, network and transport layers. The proposed schemes are implemented on a Linux machine which is called the wireless traffic controller (WTC). The WTC connects a high capacity backbone network and an access network to which the APs are attached. We evaluated the performance of the proposed WTC and confirmed that the communication quality of the multimedia streaming would be greatly improved by using this technique.

  9. ~ Effects of Data Frame Size Disbibution on Wireless LANS

    African Journals Online (AJOL)

    User

    The continuous need to replace cables and deploy mobile devices in the communications industry has led to very active research on the utilization of wireless networks. IEEE 802.11. WLAN is known to achieve relatively small throughput performance compared to the underlying physical layer's transmission rate and this is ...

  10. Effects of Data Frame Size Distribution on Wireless Lans | Aneke ...

    African Journals Online (AJOL)

    The continuous need to replace cables and deploy mobile devices in the communications industry has led to very active research on the utilization of wireless networks. IEEE 802.11 WLAN is known to achieve relatively small throughput performance compared to the underlying physical layer's transmission rate and this is ...

  11. Linux-Based Access Point Dalam Wireless LAN

    OpenAIRE

    Witono, Timotius

    2006-01-01

    Technology 802.11 which more known as WiFi, have started to become the cablereplacement technology especially in local network so-called Wireless LAN. Mostly Wireless LAN use the Infrastructure topology, which require uses of one or more Access Points as the communication center of Mobile Stations. Existence of a high quality Access Point is an important factor to determine the quality of Wireless LAN performance. Besides using Access Point that made in factory, Access Point can be custom-bui...

  12. Patient monitoring using infrastructure-oriented wireless LANs.

    Science.gov (United States)

    Varshney, Upkar

    2006-01-01

    There is considerable interest in using wireless and mobile technologies in patient monitoring in diverse environments including hospitals and nursing homes. However, there has not been much work in determining the requirements of patient monitoring and satisfying these requirements using infrastructure-oriented wireless networks. In this paper, we derive several requirements of patient monitoring and show how infrastructure-oriented wireless LANs, such as versions of IEEE 802.11, can be used to support patient monitoring in diverse environments.

  13. Wireless LAN security management with location detection capability in hospitals.

    Science.gov (United States)

    Tanaka, K; Atarashi, H; Yamaguchi, I; Watanabe, H; Yamamoto, R; Ohe, K

    2012-01-01

    In medical institutions, unauthorized access points and terminals obstruct the stable operation of a large-scale wireless local area network (LAN) system. By establishing a real-time monitoring method to detect such unauthorized wireless devices, we can improve the efficiency of security management. We detected unauthorized wireless devices by using a centralized wireless LAN system and a location detection system at 370 access points at the University of Tokyo Hospital. By storing the detected radio signal strength and location information in a database, we evaluated the risk level from the detection history. We also evaluated the location detection performance in our hospital ward using Wi-Fi tags. The presence of electric waves outside the hospital and those emitted from portable game machines with wireless communication capability was confirmed from the detection result. The location detection performance showed an error margin of approximately 4 m in detection accuracy and approximately 5% in false detection. Therefore, it was effective to consider the radio signal strength as both an index of likelihood at the detection location and an index for the level of risk. We determined the location of wireless devices with high accuracy by filtering the detection results on the basis of radio signal strength and detection history. Results of this study showed that it would be effective to use the developed location database containing radio signal strength and detection history for security management of wireless LAN systems and more general-purpose location detection applications.

  14. Proxy-Based IPv6 Neighbor Discovery Scheme for Wireless LAN Based Mesh Networks

    Science.gov (United States)

    Lee, Jihoon; Jeon, Seungwoo; Kim, Jaehoon

    Multi-hop Wireless LAN-based mesh network (WMN) provides high capacity and self-configuring capabilities. Due to data forwarding and path selection based on MAC address, WMN requires additional operations to achieve global connectivity using IPv6 address. The neighbor discovery operation over WLAN mesh networks requires repeated all-node broadcasting and this gives rise to a big burden in the entire mesh networks. In this letter, we propose the proxy neighbor discovery scheme for optimized IPv6 communication over WMN to reduce network overhead and communication latency. Using simulation experiments, we show that the control overhead and communication setup latency can be significantly reduced using the proxy-based neighbor discovery mechanism.

  15. Mining Behavioral Groups in Large Wireless LANs

    OpenAIRE

    Hsu, Wei-jen; Dutta, Debojyoti; Helmy, Ahmed

    2006-01-01

    One vision of future wireless networks is that they will be deeply integrated and embedded in our lives and will involve the use of personalized mobile devices. User behavior in such networks is bound to affect the network performance. It is imperative to study and characterize the fundamental structure of wireless user behavior in order to model, manage, leverage and design efficient mobile networks. It is also important to make such study as realistic as possible, based on extensive measure...

  16. Radiofrequency exposure from wireless LANs utilizing Wi-Fi technology.

    Science.gov (United States)

    Foster, Kenneth R

    2007-03-01

    This survey measured radiofrequency (RF) fields from wireless local area networks (WLANs) using Wi-Fi technology against a background of RF fields in the environment over the frequency range 75 MHz-3 GHz. A total of 356 measurements were conducted at 55 sites (including private residences, commercial spaces, health care and educational institutions, and other public spaces) in four countries (U.S., France, Germany, Sweden). Measurements were conducted under conditions that would result in the higher end of exposures from such systems. Where possible, measurements were conducted in public spaces as close as practical to the Wi-Fi access points. Additional measurements were conducted at a distance of approximately 1 m from a laptop while it was uploading and downloading large files to the WLAN. This distance was chosen to allow a useful comparison of fields in the far-field of the antenna in the laptop, and give a representative measure of the exposure that a bystander might receive from the laptop. The exposure to the user, particularly if the antenna of the client card were placed against his or her body, would require different measurement techniques beyond the scope of this study. In all cases, the measured Wi-Fi signal levels were very far below international exposure limits (IEEE C95.1-2005 and ICNIRP) and in nearly all cases far below other RF signals in the same environments. An discusses technical aspects of the IEEE 802.11 standard on which WLANs operate that are relevant to determining the levels of RF energy exposure from WLANs. Important limiting factors are the low operating power of client cards and access points, and the low duty cycle of transmission that normally characterizes their operation.

  17. Millimeter-wave Wireless LAN and its Extension toward 5G Heterogeneous Networks

    OpenAIRE

    Sakaguchi, Kei; Mohamed, Ehab Mahmoud; Kusano, Hideyuki; Mizukami, Makoto; Miyamoto, Shinichi; Rezagah, Roya; Takinami, Koji; Takahashi, Kazuaki; Shirakata, Naganori; Peng, Hailan; Yamamoto, Toshiaki; Namba, Shinobu

    2015-01-01

    Millimeter-wave (mmw) frequency bands, especially 60 GHz unlicensed band, are considered as a promising solution for gigabit short range wireless communication systems. IEEE standard 802.11ad, also known as WiGig, is standardized for the usage of the 60 GHz unlicensed band for wireless local area networks (WLANs). By using this mmw WLAN, multi-Gbps rate can be achieved to support bandwidth-intensive multimedia applications. Exhaustive search along with beamforming (BF) is usually used to over...

  18. Recommended Practices Guide Securing WLANs using 802.11i

    Energy Technology Data Exchange (ETDEWEB)

    Masica, K

    2006-10-16

    This paper addresses design principles and best practices regarding the implementation and operation of Wireless LAN (WLAN) communication networks based on the 802.11i security standard. First, a general overview of WLAN technology and standards is provided in order to ground the discussion in the evolution of WLAN standards and security approaches. This is followed by a detailed explanation of the 802.11i standard for securing WLAN networks. Principles for designing secure WLAN networks are then presented, followed by a list of specific best practices that can be used as a guideline for organizations considering the deployment of WLAN networks for non-critical control and monitoring applications. Finally, a section on technical issues and considerations for deploying WLAN networks in critical environments is presented.

  19. Handoff Between a Wireless Local Area Network (WLAN and a Wide Area Network (UMTS

    Directory of Open Access Journals (Sweden)

    J. Sánchez–García

    2009-04-01

    Full Text Available With the appearance of wireless data networks with variable coverage, band width and handoff strategies, in addition to the growing need of mobile nodes to freely roam among these networks, the support of an interoperable handoff strategy for hybrid wireless data networks is a requirement that needs to be addressed. The current trend in wireless data networks is to offer multimedia access to mobile users by employing the wireless local area network (WLAN standard IEEE802.11 while the user is located indoors; on the other hand, 3rd generation wireless networks (WAN are being deployed to provide coverage while the user is located outdoors. As a result, the mobile node will require a handoff mechanism to allow the user to roam between WLAN and WAN environments; up to this date several strategies have been proposed (Sattari et al., 2004 and HyoJin, 2007 in the literature, however, none of these have been standardized to date. To support this interoperability, the mobile node must be equipped with configurable wireless inetrfaces to support the handoff between the WLAN and the WAN networks. In this work a new algorithm is proposed to allow a mobile node to roam between a wireless local area network (IEEE802.11 and a WAN base station (UMTS, while employing IP mobility support. The algorithm is implemented in simulation, using the Network Simulator 2.

  20. Bandwidth Estimation in Wireless Lans for Multimedia Streaming Services

    Directory of Open Access Journals (Sweden)

    Heung Ki Lee

    2007-01-01

    Full Text Available The popularity of multimedia streaming services via wireless networks presents major challenges in the management of network bandwidth. One challenge is to quickly and precisely estimate the available bandwidth for the decision of streaming rates of layered and scalable multimedia services. Previous studies based on wired networks are too burdensome to be applied to multimedia applications in wireless networks. In this paper, a new method, IdleGap, is suggested to estimate the available bandwidth of a wireless LAN based on the information from a low layer in the protocol stack. We use a network simulation tool, NS-2, to evaluate our new method with various ranges of cross-traffic and observation times. Our simulation results show that IdleGap accurately estimates the available bandwidth for all ranges of cross-traffic (100 Kbps ∼ 1 Mbps with a very short observation time of 10 seconds.

  1. Functional Analysis of a SDR Based Bluetooth/HiperLAN Terminal Demonstrator

    NARCIS (Netherlands)

    Hoeksema, F.W.; Schiphorst, Roelof; Slump, Cornelis H.

    2001-01-01

    |In our Software Defined Radio (SDR) project we aim at combining two different types of standards, Bluetooth and HiperLAN/2 on one common hardware platform. HiperLAN/2 is a high-speed Wireless LAN (WLAN) standard, whereas Bluetooth is a low-cost and low-speed Personal Area Network (PAN) standard. An

  2. WLAN-VERKON SUUNNITTELU JA TESTAUS : Wireless Local Area Network (WLAN) design and testing

    OpenAIRE

    Isotalo, Atte

    2017-01-01

    Tämän työn aiheena oli WLAN-verkon suunnittelu ja toteutus käyttämällä Savoniaammattikorkeakoulun tarjoamia laitteita. Opinnäytetyön teko aloitettiin etsimällä taustamateriaalia työn suorittamiseen. Opinnäytetyössä käytettiin esimerkki tietoverkkoa testauksia varten. Esimerkkiverkossa testattiin koulun tilaamaa langattoman verkon ohjaustilaitetta. Esimerkkiverkkoni sisälsi kaksi OSI-mallin toisen tason kytkintä, yhden OSI-mallin kolmannen tason kytkimen, kaksi langattoman verkon tuki...

  3. The Security Aspects of Wireless Local Area Network (WLAN)

    Science.gov (United States)

    2003-09-01

    remote users. In the remote user application, the VPN provides a secure tunnel over the insecure network. The three most common VPN communications...protocol standards are used with, Point-to- Point Tunneling Protocol (PPTP), Layer 2 Tunneling Protocol (L2TP), and Internet Protocol Security ( IPSec ...users in homes and hot spot environments, such as airports and campuses . However, WLANs have serious

  4. Rogue AP Detection in the Wireless LAN for Large Scale Deployment

    Directory of Open Access Journals (Sweden)

    Sang-Eon Kim

    2006-10-01

    Full Text Available The wireless LAN standard, also known as WiFi, has begun to use commercial purposes. This paper describes access network architecture of wireless LAN for large scale deployment to provide public service. A metro Ethernet and digital subscriber line access network can be used for wireless LAN with access point. In this network architecture, access point plays interface between wireless node and network infrastructure. It is important to maintain access point without any failure and problems to public users. This paper proposes definition of rogue access point and classifies based on functional problem to access the Internet. After that, rogue access point detection scheme is described based on classification over the wireless LAN. The rogue access point detector can greatly improve the network availability to network service provider of wireless LAN.

  5. Development of GPS data remote retrieval system using wireless LAN

    Directory of Open Access Journals (Sweden)

    Koichiro Doi

    2012-11-01

    Full Text Available A remote retrieval system, using a wireless LAN, was developed to retrieve dual-frequency GPS data. The system consists of a ground observation unit (comprising a dual-frequency GPS logger and a data transmission unit and a data retrieval unit. In this system, we use the ZigBee communication protocol to transmit control commands (2.4 GHz, 250 Kbps and a wireless LAN communication to transmit GPS data (2.4 GHz, 54 Mbps. Data of every 30 seconds to transmit to the data retrieval unit are re-sampled from 1-second data at 00 UT each day. We conducted three data-transmission tests with the system: (1 a ground data retrieval test, (2 a data retrieval test from the atmosphere of a few hundred meters high using a small unmanned aircraft, and (3 actual GPS-data retrieval tests from a GPS buoy deployed on sea ice at Nisi-no-ura Cove, Syowa Station, Antarctica. In test (1, we successfully received all the data from the ground observation unit when situated at distances of less than 400 m from the data retrieval unit. In test (2, we obtained approximately 24.5 MB of data from the aircraft at heights of less than 250 m. In test (3, we obtained approximately 23.5 MB of data from the GPS buoy within 10 minutes. The proposed system has the advantage of enabling continuous measurements without aborting the measurement at the data retrievals.

  6. Network preservation through a topology control algorithm for wireless mesh networks

    CSIR Research Space (South Africa)

    Aron, FO

    2008-09-01

    Full Text Available Wireless mesh networks (WMNs) is becoming a promising new technology for extending coverage to farflung rural areas. This it achieves by linking the various wireless LANS (WLANs) in distant locations thus providing a vital mode complimentary...

  7. Wireless local area network. A new technology of network

    International Nuclear Information System (INIS)

    Wu Yunjun; Zhao Zongtao

    2003-01-01

    This paper introduces Wireless Local Area Network (WLAN), including the concept, history, characters and the foreground of its development, it also narrates in detail the several key techniques used to implement IEEE802.11 WLAN, and ideas on key technology of future progress in wireless LAN field have also been presented. (authors)

  8. Corrections to "Connectivity-Based Reliable Multicast MAC Protocol for IEEE 802.11 Wireless LANs"

    Directory of Open Access Journals (Sweden)

    Choi Woo-Yong

    2010-01-01

    Full Text Available We have found the errors in the throughput formulae presented in our paper "Connectivity-based reliable multicast MAC protocol for IEEE 802.11 wireless LANs". We provide the corrected formulae and numerical results.

  9. A Seamless Handoff Scheme with Access Point Load Balance for Real-Time Services Support in 802.11 Wireless LANs

    Science.gov (United States)

    Manodham, Thavisak; Loyola, Luis; Miki, Tetsuya

    IEEE 802.11 wirelesses LANs (WLANs) have been rapidly deployed in enterprises, public areas, and households. Voice-over-IP (VoIP) and similar applications are now commonly used in mobile devices over wireless networks. Recent works have improved the quality of service (QoS) offering higher data rates to support various kinds of real-time applications. However, besides the need for higher data rates, seamless handoff and load balancing among APs are key issues that must be addressed in order to continue supporting real-time services across wireless LANs and providing fair services to all users. In this paper, we introduce a novel access point (AP) with two transceivers that improves network efficiency by supporting seamless handoff and traffic load balancing in a wireless network. In our proposed scheme, the novel AP uses the second transceiver to scan and find neighboring STAs in the transmission range and then sends the results to neighboring APs, which compare and analyze whether or not the STA should perform a handoff. The initial results from our simulations show that the novel AP module is more effective than the conventional scheme and a related work in terms of providing a handoff process with low latency and sharing traffic load with neighbor APs.

  10. The Enhanced Workflow and Efficiency of the Wireless Local Area Network (WLAN)-Based Direct Digital Radiography (DDR) Portable Radiography.

    Science.gov (United States)

    Ngan, Tsz-Lung; Wong, Edward Ting-Hei; Ng, Kris Lap-Shun; Jeor, Patrick Kwok-Shing; Lo, Gladys Goh

    2015-06-01

    With the implementation of the PACS in the hospital, there is an increasing demand from the clinicians for immediate access and display of radiological images. Recently, our hospital has installed the first wireless local area network (WLAN)-based direct digital radiography (DDR) portable radiography system. The DDR portable radiography system allows wireless retrieval of modality worklist and wireless transmission of portable X-ray image on the console to the Picture Archiving and Communication System (PACS), via WLAN connection of wireless fidelity (Wi-Fi). The aim of this study was to analyze the workflow and performance between the WLAN-based DDR portable radiography system and the old practice using conventional portable X-ray machine with computed radiography (CR) system. A total of 190 portable chest X-ray examinations were evaluated and timed, using the conventional portable X-ray machine with CR from March to April of 2012 and using the new DDR portable radiography system on December of 2012 (n = 97 for old system and n = 93 for DDR portable system). The time interval of image becoming available to the PACS using the WLAN-based DDR portable radiography system was significantly shorter than that of the old practice using the conventional portable X-ray machine with CR (6.8 ± 2.6 min for DDR portable system; 23 ± 10.2 min for old system; p DDR portable radiography system can enhance the workflow of portable radiography by reduction of procedural steps.

  11. A study of the impact of frequency selectivity on link adaptive wireless LAN systems

    OpenAIRE

    Armour, SMD; Doufexi, A; Nix, AR; Bull, DR

    2002-01-01

    Wireless local area networks (WLANs) supporting broadband multimedia communication are being developed and standardized around the world. The HIPERLAN/2, 802.11a and HiSWANa standards provide channel adaptive data rates between 6 and 54 Mbps in the 5GHz radio band. The link adaptation mechanism is not specified in the standards. In this paper the performance of the HIPERLAN/2 system is evaluated in terms of throughput in a range of test channels with different degrees of frequency selectivity...

  12. A Wireless LAN and Voice Information System for Underground Coal Mine

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    2014-06-01

    Full Text Available In this paper we constructed a wireless information system, and developed a wireless voice communication subsystem based on Wireless Local Area Networks (WLAN for underground coal mine, which employs Voice over IP (VoIP technology and Session Initiation Protocol (SIP to achieve wireless voice dispatching communications. The master control voice dispatching interface and call terminal software are also developed on the WLAN ground server side to manage and implement the voice dispatching communication. A testing system for voice communication was constructed in tunnels of an underground coal mine, which was used to actually test the wireless voice communication subsystem via a network analysis tool, named Clear Sight Analyzer. In tests, the actual flow charts of registration, call establishment and call removal were analyzed by capturing call signaling of SIP terminals, and the key performance indicators were evaluated in coal mine, including average subjective value of voice quality, packet loss rate, delay jitter, disorder packet transmission and end-to- end delay. Experimental results and analysis demonstrate that the wireless voice communication subsystem developed communicates well in underground coal mine environment, achieving the designed function of voice dispatching communication.

  13. Application of wireless LAN technology to remote monitoring for inspection equipment

    International Nuclear Information System (INIS)

    Ishiyama, Koichi; Kimura, Takashi; Miura, Yasushi; Yamaguchi, Katsuhiro; Kabuki, Toshihide

    2011-01-01

    To support inspections under an Integrated Safeguards regime into Tokai Reprocessing Plant (TRP), the IAEA suggested making use of Remote Monitoring (RM) capabilities to the inspection equipment (surveillance camera and NDA systems) installed in the spent fuel storage area at TRP. Since TRP had no pre-prepared cabling infrastructure for data transmission in the spent fuel storage area, the option of wireless LAN was chosen over the telephone line due to its lower installation costs. Feasibility studies and tests were performed by TRP on communication and particularly on long-term continuous communication using wireless LAN equipment composed of APs (AP: Access Point) and the external antennas for introducing wireless LAN technology to RM. As a result it was recognized that wireless LAN has enough ability to communicate for long periods of time and consequently the IAEA installed the AP and the external antenna to each inspection equipment and the wireless LAN technology was applied for RM. In this paper, the summary of each test and the results are reported. (author)

  14. Installation of secure, always available wireless LAN systems as a component of the hospital communication infrastructure.

    Science.gov (United States)

    Hanada, Eisuke; Kudou, Takato; Tsumoto, Shusaku

    2013-06-01

    Wireless technologies as part of the data communication infrastructure of modern hospitals are being rapidly introduced. Even though there are concerns about problems associated with wireless communication security, the demand is remarkably large. In addition, insuring that the network is always available is important. Herein, we discuss security countermeasures and points to insure availability that must be taken to insure safe hospital/business use of wireless LAN systems, referring to the procedures introduced at Shimane University Hospital. Security countermeasures differ according to their purpose, such as for preventing illegal use or insuring availability, both of which are discussed. It is our hope that this information will assist others in their efforts to insure safe implementation of wireless LAN systems, especially in hospitals where they have the potential to greatly improve information sharing and patient safety.

  15. Ensuring the security and availability of a hospital wireless LAN system.

    Science.gov (United States)

    Hanada, Eisuke; Kudou, Takato; Tsumoto, Shusaku

    2013-01-01

    Wireless technologies as part of the data communication infrastructure of modern hospitals are being rapidly introduced. Even though there are concerns about problems associated with wireless communication security, the demand is remarkably large. Herein we discuss security countermeasures that must be taken and issues concerning availability that must be considered to ensure safe hospital/business use of wireless LAN systems, referring to the procedures introduced at a university hospital. Security countermeasures differ according to their purpose, such as preventing illegal use or ensuring availability, both of which are discussed. The main focus of the availability discussion is on signal reach, electromagnetic noise elimination, and maintaining power supply to the network apparatus. It is our hope that this information will assist others in their efforts to ensure safe implementation of wireless LAN systems, especially in hospitals where they have the potential to greatly improve information sharing and patient safety.

  16. Optimized tuning of contention window for IEEE 802.11 WLAN

    African Journals Online (AJOL)

    2, pp.151-70. Bononi L., Marco C., Enrico G. 2004. Runtime optimization of IEEE 802.11 wireless LANs performance.IEEE Transactions on. Parallel and Distributed Systems. Vol. 15, No.1 , pp.66-80. Hong K., Lee S., Kim K., Kim Y. 2012. Channel condition based contention window adaptation in IEEE 802.11 WLANs. IEEE.

  17. Software-Defined Radio Testbed for the Physical Layer of Wireless LANs

    NARCIS (Netherlands)

    Schiphorst, Roelof; Moseley, N.A.; Slump, Cornelis H.

    2005-01-01

    This paper presents a software-defined radio testbed for the physical layer of wireless LAN standards. All baseband physical layer functions have been successfully mapped on a Pentium~4 processor that performs these functions in real-time. This has been tested in combination with a CMOS integrated

  18. Frequency division multiplexing in wireless underwater acoustic LANs

    Science.gov (United States)

    Bessios, Anthony G.; Caimi, Frank M.

    1995-09-01

    On overview of optical technologies, active and passive components, and systems that are deemed suitable for wireless communications is presented in this paper. Specifically addressed is the use of onboard photonics in advanced spacecraft, satellite, etc. for applications in wireless communications. To assess its viability in potential commercial applications, the state-of-the-art of phonics technology and future prospects for economical large capacity multi-channel services is briefly reviewed.

  19. BER IMPROVEMENT OF WIRELESS LAN IEEE 802.11 STANDARD USING WAVELET PACKET TRANSFORMS

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar

    2012-09-01

    Full Text Available High data rates and spectral efficiency is the main requirements for wireless communication systems. Orthogonal Frequency Division Multiplexing (OFDM is a special form of multi carrier transmission used to achieve high data rates of the various WLAN standards. WLAN uses an Inverse Fast Fourier Transform (IFFT at the transmitter to modulate a high bit-rate signal onto a number of carriers and ensure orthogonality between the carriers. The FFT-OFDM has a disadvantage that it is inherently inflexible and requires a complex IFFT core. Recently, Wavelet Packet Transform is proposed as an alternate to FFT. It is a multiplexing method in which data is assigned to wavelet sub bands having different time and frequency resolutions. This paper presents a BER analysis of Fourier-based OFDM (FFT-OFDM and Wavelet Packet based OFDM (WPT-OFDM in WLAN standard (IEEE 802.11a. The performance of FFT and WPT OFDM for various modulation techniques such as PSK, DPSK and QAM for varying values of M was evaluated in AWGN Channel.

  20. Latency and Jitter Analysis for IEEE 802.11e Wireless LANs

    Directory of Open Access Journals (Sweden)

    Sungkwan Youm

    2013-01-01

    Full Text Available This paper presents a numerical analysis of latency and jitter for IEEE 802.11e wireless local area networks (WLANs in a saturation condition, by using a Markov model. We use this model to explicate how the enhanced distributed coordination function (EDCF differentiates classes of service and to characterize the probability distribution of the medium access control (MAC layer packet latency and jitter, on which the quality of the voice over Internet protocol (VoIP calls is dependent. From the proposed analytic model, we can estimate the available number of nodes determining the system performance, in order to satisfy user demands on the latency and jitter.

  1. Coexistence issues for a 2.4 GHz wireless audio streaming in presence of bluetooth paging and WLAN

    Science.gov (United States)

    Pfeiffer, F.; Rashwan, M.; Biebl, E.; Napholz, B.

    2015-11-01

    Nowadays, customers expect to integrate their mobile electronic devices (smartphones and laptops) in a vehicle to form a wireless network. Typically, IEEE 802.11 is used to provide a high-speed wireless local area network (WLAN) and Bluetooth is used for cable replacement applications in a wireless personal area network (PAN). In addition, Daimler uses KLEER as third wireless technology in the unlicensed (UL) 2.4 GHz-ISM-band to transmit full CD-quality digital audio. As Bluetooth, IEEE 802.11 and KLEER are operating in the same frequency band, it has to be ensured that all three technologies can be used simultaneously without interference. In this paper, we focus on the impact of Bluetooth and IEEE 802.11 as interferer in presence of a KLEER audio transmission.

  2. Enhancing MAC performance of DCF protocol for IEEE 802.11 wireless LANs

    Science.gov (United States)

    Choi, Woo-Yong

    2017-01-01

    The DCF (Distributed Coordination Function) is the basic MAC (Medium Access Control) protocol of IEEE 802.11 wireless LANs and compatible with various IEEE 802.11 PHY extensions. The performance of the DCF degrades exponentially as the number of nodes participating in the DCF transmission procedure increases. To deal with this problem, we propose a simple, however efficient modification of the DCF by which the performance of the DCF is greatly enhanced.

  3. Information technology -- Telecommunications and information exchange between systems -- Local and metropolitan area networks -- Specific requirements -- Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications

    CERN Document Server

    International Organization for Standardization. Geneva

    1997-01-01

    Information technology -- Telecommunications and information exchange between systems -- Local and metropolitan area networks -- Specific requirements -- Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications

  4. An Assessment of the Audio Codec Performance in Voice over WLAN (VoWLAN) Systems

    OpenAIRE

    Narbutt, Miroslaw; Davis, Mark

    2005-01-01

    In this paper we present results of experimental investigation into the performance of three audio codecs (ITU-T G.711, G.723.1 and G.729A) under varying load conditions on a Voice over WLAN system utilizing the IEEE 802.11b wireless LAN standard. The analysis is based upon a new technique for estimating user satisfaction of speech quality calculated from packet delay and packet loss/late measurements. We also demonstrate the importance of the de-jitter buffer playout scheme for insuring spee...

  5. Connectivity-Based Reliable Multicast MAC Protocol for IEEE 802.11 Wireless LANs

    Directory of Open Access Journals (Sweden)

    Woo-Yong Choi

    2009-01-01

    Full Text Available We propose the efficient reliable multicast MAC protocol based on the connectivity information among the recipients. Enhancing the BMMM (Batch Mode Multicast MAC protocol, the reliable multicast MAC protocol significantly reduces the RAK (Request for ACK frame transmissions in a reasonable computational time and enhances the MAC performance. By the analytical performance analysis, the throughputs of the BMMM protocol and our proposed MAC protocol are derived. Numerical examples show that our proposed MAC protocol increases the reliable multicast MAC performance for IEEE 802.11 wireless LANs.

  6. Dynamic Contention Window Control Scheme in IEEE 802.11e EDCA-Based Wireless LANs

    Science.gov (United States)

    Abeysekera, B. A. Hirantha Sithira; Matsuda, Takahiro; Takine, Tetsuya

    In the IEEE 802.11 MAC protocol, access points (APs) are given the same priority as wireless terminals in terms of acquiring the wireless link, even though they aggregate several downlink flows. This feature leads to a serious throughput degradation of downlink flows, compared with uplink flows. In this paper, we propose a dynamic contention window control scheme for the IEEE 802.11e EDCA-based wireless LANs, in order to achieve fairness between uplink and downlink TCP flows while guaranteeing QoS requirements for real-time traffic. The proposed scheme first determines the minimum contention window size in the best-effort access category at APs, based on the number of TCP flows. It then determines the minimum and maximum contention window sizes in higher priority access categories, such as voice and video, so as to guarantee QoS requirements for these real-time traffic. Note that the proposed scheme does not require any modification to the MAC protocol at wireless terminals. Through simulation experiments, we show the effectiveness of the proposed scheme.

  7. IEEE 802.11 Wireless LANs: Performance Analysis and Protocol Refinement

    Directory of Open Access Journals (Sweden)

    Chatzimisios P.

    2005-01-01

    Full Text Available The IEEE 802.11 protocol is emerging as a widely used standard and has become the most mature technology for wireless local area networks (WLANs. In this paper, we focus on the tuning of the IEEE 802.11 protocol parameters taking into consideration, in addition to throughput efficiency, performance metrics such as the average packet delay, the probability of a packet being discarded when it reaches the maximum retransmission limit, the average time to drop a packet, and the packet interarrival time. We present an analysis, which has been validated by simulation that is based on a Markov chain model commonly used in the literature. We further study the improvement on these performance metrics by employing suitable protocol parameters according to the specific communication needs of the IEEE 802.11 protocol for both basic access and RTS/CTS access schemes. We show that the use of a higher initial contention window size does not considerably degrade performance in small networks and performs significantly better in any other scenario. Moreover, we conclude that the combination of a lower maximum contention window size and a higher retry limit considerably improves performance. Results indicate that the appropriate adjustment of the protocol parameters enhances performance and improves the services that the IEEE 802.11 protocol provides to various communication applications.

  8. Reliable Multicast MAC Protocol for IEEE 802.11 Wireless LANs with Extended Service Range

    Science.gov (United States)

    Choi, Woo-Yong

    2011-11-01

    In this paper, we propose the efficient reliable multicast MAC protocol by which the AP (Access Point) can transmit reliably its multicast data frames to the recipients in the AP's one-hop or two-hop transmission range. The AP uses the STAs (Stations) that are directly associated with itself as the relays for the data delivery to the remote recipients that cannot be reached directly from itself. Based on the connectivity information among the recipients, the reliable multicast MAC protocol optimizes the number of the RAK (Request for ACK) frame transmissions in a reasonable computational time. Numerical examples show that our proposed MAC protocol significantly enhances the MAC performance compared with the BMMM (Batch Mode Multicast MAC) protocol that is extended to support the recipients that are in the AP's one-hop or two-hop transmission range in IEEE 802.11 wireless LANs.

  9. Cluster-Based Multipolling Sequencing Algorithm for Collecting RFID Data in Wireless LANs

    Science.gov (United States)

    Choi, Woo-Yong; Chatterjee, Mainak

    2015-03-01

    With the growing use of RFID (Radio Frequency Identification), it is becoming important to devise ways to read RFID tags in real time. Access points (APs) of IEEE 802.11-based wireless Local Area Networks (LANs) are being integrated with RFID networks that can efficiently collect real-time RFID data. Several schemes, such as multipolling methods based on the dynamic search algorithm and random sequencing, have been proposed. However, as the number of RFID readers associated with an AP increases, it becomes difficult for the dynamic search algorithm to derive the multipolling sequence in real time. Though multipolling methods can eliminate the polling overhead, we still need to enhance the performance of the multipolling methods based on random sequencing. To that extent, we propose a real-time cluster-based multipolling sequencing algorithm that drastically eliminates more than 90% of the polling overhead, particularly so when the dynamic search algorithm fails to derive the multipolling sequence in real time.

  10. A Rate Adaptation Scheme According to Channel Conditions in Wireless LANs

    Science.gov (United States)

    Numoto, Daisuke; Inai, Hiroshi

    Rate adaptation in wireless LANs is to select the most suitable transmission rate automatically according to channel condition. If the channel condition is good, a station can choose a higher transmission rate, otherwise, it should choose a lower but noise-resistant transmission rate. Since IEEE 802.11 does not specify any rate adaptation scheme, several schemes have been proposed. However those schemes provide low throughput or unfair transmission opportunities among stations especially when the number of stations increases. In this paper, we propose a rate adaptation scheme under which the transmission rate quickly closes and then stays around an optimum rate even in the presence of a large number of stations. Via simulation, our scheme provides higher throughput than existing ones and almost equal fairness.

  11. A New MAC Protocol with Pseudo-TDMA Behavior for Supporting Quality of Service in 802.11 Wireless LANs

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available A new medium access control (MAC protocol is proposed for quality-of-service (QoS support in wireless local area networks (WLAN. The protocol is an alternative to the recent enhancement 802.11e. A new priority policy provides the system with better performance by simulating time division multiple access (TDMA functionality. Collisions are reduced and starvation of low-priority classes is prevented by a distributed admission control algorithm. The model performance is found analytically extending previous work on this matter. The results show that a better organization of resources is achieved through this scheme. Throughput analysis is verified with OPNET simulations.

  12. Indoor Propagation Measurement for WLAN Systems Operating in 2.45 GHz ISM Band

    Directory of Open Access Journals (Sweden)

    P. Pechac

    2002-12-01

    Full Text Available For a planning of indoor Wireless LAN systems working in the ISMband, the signal propagation prediction is needed. In this article, themeasurement campaign based on two types of measurements at 2.45 GHz isintroduced. The first type of the measurement was a classicalnarrowband signal level measurement within indoor scenario withoutpresence of people. The aim of this measurement was to find empiricalparameters for COST231 Multi-Wall and One-Slope models. In order tostatistically describe the time varying nature of the received envelopeof the signal, at WLAN 2.45 GHz band, the second part of measurementcampaign was accomplished. In this case, the signal level was measuredusing commercial WLAN PCMCIA cards in two notebooks. Probabilitydensity functions and corresponding cumulative distribution functionswere set and discussed based on the specific locations and orientationof one of the notebooks. Results from both measurement campaigns werecompared and conclusions are drawn for the needs of practical planningof indoor WLAN systems coverage.

  13. Voice over IP: improving the quality over wireless LAN by adopting a booster mechanism: an experimental approach

    Science.gov (United States)

    Hoene, Christian; Carreras, Iacopo; Wolisz, Adam

    2001-07-01

    The performance of unreliable voice transmission (Voice over IP) over wireless links is measured not by the throughput but by the perceptual speech quality. The speech quality is impaired by packet losses, which are common on wireless links, and by high transmission delays. In this paper, we describe the design and implementation of a novel Speech Property Based Booster that improves the quality of voice over wireless LANs. This booster is in compliance with existing standards and is transparent to other protocols. It uses characteristics of human speech production and features of modern audio codecs to distinguish packets regarding their importance for perceptual quality. Important packets are protected at the link layer by three mechanisms: selective packet loss recovery, redundant transmission and a hybrid solution. These mechanisms have been evaluated using an experimental set-up with commercial wireless LAN equipment. We made measurements of the objective audio quality and analyzed the effects of packet losses, both due to real wireless channels and late packet arrivals. Our experiments show that the booster increases the quality of voice best with the hybrid solution and that the performance of Voice over IP can be improved further.

  14. A New Three-Dimensional Indoor Positioning Mechanism Based on Wireless LAN

    Directory of Open Access Journals (Sweden)

    Jiujun Cheng

    2014-01-01

    Full Text Available The researches on two-dimensional indoor positioning based on wireless LAN and the location fingerprint methods have become mature, but in the actual indoor positioning situation, users are also concerned about the height where they stand. Due to the expansion of the range of three-dimensional indoor positioning, more features must be needed to describe the location fingerprint. Directly using a machine learning algorithm will result in the reduced ability of classification. To solve this problem, in this paper, a “divide and conquer” strategy is adopted; that is, first through k-medoids algorithm the three-dimensional location space is clustered into a number of service areas, and then a multicategory SVM with less features is created for each service area for further positioning. Our experiment shows that the error distance resolution of the approach with k-medoids algorithm and multicategory SVM is higher than that of the approach only with SVM, and the former can effectively decrease the “crazy prediction.”

  15. Exposure of the general public due to wireless LAN applications in public places

    International Nuclear Information System (INIS)

    Schmid, G.; Preiner, P.; Lager, D.; Ueberbacher, R.; Georg, R.

    2007-01-01

    The typical exposure caused by wireless LAN applications in public areas has been investigated in a variety of scenarios. Small-sized (internet cafe) and large-scale (airport) indoor scenarios as well as outdoor scenarios in the environment of access points (AP) supplying for residential areas and public places were considered. The exposure assessment was carried out by numerical GTD/UTD computations based on optical wave propagation, as well as by verifying frequency selective measurements in the considered scenarios under real life conditions. In the small-sized indoor scenario the maximum temporal peak values of power density, spatially averaged over body dimensions, were found to be lower than 20 mW/m 2 , corresponding to 0.2% of the reference level according to the European Council Recommendation 1999/519/EC. Local peak values of power density might be 1-2 orders of magnitude higher, spatial and time-averaged values for usual data traffic conditions might be 2-3 orders of magnitude lower, depending on the actual data traffic. In the considered outdoor scenarios, exposure was several orders of magnitude lower than in indoor scenarios due to the usually larger distances to the AP antennas. (authors)

  16. A Cross-Layer Key Management Scheme for MIPv6 Fast Handover over IEEE 802.11 Wireless LAN

    Directory of Open Access Journals (Sweden)

    Chang-Seop Park

    2015-01-01

    Full Text Available A new key management and security scheme is proposed to integrate Layer Two (L2 and Layer Three (L3 keys for secure and fast Mobile IPv6 handover over IEEE 802.11 Wireless Local Area Network (WLAN. Unlike the original IEEE 802.11-based Mobile IPv6 Fast Handover (FMIPv6 that requires time-consuming IEEE 802.1x-based Extensible Authentication Protocol (EAP authentication on each L3 handover, the newly proposed key management and security scheme requires only one 802.1x-EAP regardless of how many L3 handovers occur. Therefore, the proposed scheme reduces the handover latency that results from a lengthy 802.1x-based EAP. The proposed key management and security scheme is extensively analyzed in terms of security and performance, and the proposed security scheme is shown to be more secure than those that were previously proposed.

  17. Media Access Time-Rearrangement of Wireless LAN for a Multi-Radio Collocated Platform

    Science.gov (United States)

    Shin, Sang-Heon; Kim, Chul; Park, Sang Kyu

    With the advent of new Radio Access Technologies (RATs), it is inevitable that several RATs will co-exist, especially in the license-exempt band. In this letter, we present an in-depth adaptation of the proactive time-rearrangement (PATRA) scheme for IEEE 802.11 WLAN. The PATRA is a time division approach for reducing interference from a multi-radio device. Because IEEE 802.11 is based on carrier sensing and contention mechanism, it is the most suitable candidate to adapt the PATRA.

  18. Impact of cell load on 5GHz IEEE 802.11 WLAN

    OpenAIRE

    Abu-Tair, Mamoun; Bhatti, Saleem Noel

    2017-01-01

    We have conducted an empirical study of the latest 5GHz IEEE 802.11 wireless LAN (WLAN) variants of 802.11n (5GHz) and 802.11ac (Wave 1), under different cell load conditions. We have considered typical configurations of both protocols on a Linux testbed. Under light load,there is no clear difference between 802.11n and 802.11ac in terms of performance and energy consumption. However, in some cases of high cell load, we have found that there may be a small advantage with 802.11ac. Overall, we...

  19. Analysis of Adaptive Control Scheme in IEEE 802.11 and IEEE 802.11e Wireless LANs

    Science.gov (United States)

    Lee, Bih-Hwang; Lai, Hui-Cheng

    In order to achieve the prioritized quality of service (QoS) guarantee, the IEEE 802.11e EDCAF (the enhanced distributed channel access function) provides the distinguished services by configuring the different QoS parameters to different access categories (ACs). An admission control scheme is needed to maximize the utilization of wireless channel. Most of papers study throughput improvement by solving the complicated multidimensional Markov-chain model. In this paper, we introduce a back-off model to study the transmission probability of the different arbitration interframe space number (AIFSN) and the minimum contention window size (CWmin). We propose an adaptive control scheme (ACS) to dynamically update AIFSN and CWmin based on the periodical monitoring of current channel status and QoS requirements to achieve the specific service differentiation at access points (AP). This paper provides an effective tuning mechanism for improving QoS in WLAN. Analytical and simulation results show that the proposed scheme outperforms the basic EDCAF in terms of throughput and service differentiation especially at high collision rate.

  20. Transmission History Based Distributed Adaptive Contention Window Adjustment Algorithm Cooperating with Automatic Rate Fallback for Wireless LANs

    Science.gov (United States)

    Ogawa, Masakatsu; Hiraguri, Takefumi; Nishimori, Kentaro; Takaya, Kazuhiro; Murakawa, Kazuo

    This paper proposes and investigates a distributed adaptive contention window adjustment algorithm based on the transmission history for wireless LANs called the transmission-history-based distributed adaptive contention window adjustment (THAW) algorithm. The objective of this paper is to reduce the transmission delay and improve the channel throughput compared to conventional algorithms. The feature of THAW is that it adaptively adjusts the initial contention window (CWinit) size in the binary exponential backoff (BEB) algorithm used in the IEEE 802.11 standard according to the transmission history and the automatic rate fallback (ARF) algorithm, which is the most basic algorithm in automatic rate controls. This effect is to keep CWinit at a high value in a congested state. Simulation results show that the THAW algorithm outperforms the conventional algorithms in terms of the channel throughput and delay, even if the timer in the ARF is changed.

  1. WLAN Technologies for Audio Delivery

    Directory of Open Access Journals (Sweden)

    Nicolas-Alexander Tatlas

    2007-01-01

    Full Text Available Audio delivery and reproduction for home or professional applications may greatly benefit from the adoption of digital wireless local area network (WLAN technologies. The most challenging aspect of such integration relates the synchronized and robust real-time streaming of multiple audio channels to multipoint receivers, for example, wireless active speakers. Here, it is shown that current WLAN solutions are susceptible to transmission errors. A detailed study of the IEEE802.11e protocol (currently under ratification is also presented and all relevant distortions are assessed via an analytical and experimental methodology. A novel synchronization scheme is also introduced, allowing optimized playback for multiple receivers. The perceptual audio performance is assessed for both stereo and 5-channel applications based on either PCM or compressed audio signals.

  2. Wireless Networks: New Meaning to Ubiquitous Computing.

    Science.gov (United States)

    Drew, Wilfred, Jr.

    2003-01-01

    Discusses the use of wireless technology in academic libraries. Topics include wireless networks; standards (IEEE 802.11); wired versus wireless; why libraries implement wireless technology; wireless local area networks (WLANs); WLAN security; examples of wireless use at Indiana State University and Morrisville College (New York); and useful…

  3. Adaptive subcarrier selection for mitigating Bluetooth interference in OFDM-based wireless LANS operating at 2.4 ghz

    Science.gov (United States)

    Chari, Srikant K.

    2003-07-01

    IEEE 802.11g WLANs operating at 2.4 GHz face interference from Bluetooth which also uses the same frequency. IEEE 802.11g is an orthogonal frequency divison multiplexing (OFDM) based WLAN standard. Adaptive subcarrier selection (ASuS) involves using feedback from the receiver to dynamically allocate subcarriers for OFDM transmission. This paper proposes a method to avoid Bluetooth interference using ASuS. By adaptively choosing subcarriers for OFDM transmission, the frequencies used by Bluetooth can be avoided. Power level deviations in small groups of contiguous subcarriers with respect to other subcarriers in an OFDM symbol can be used as an indication of Bluetooth interference. Simulations show that as compared to the conventional OFDM technique, adaptive subcarrier selection results in significant reduction in the packet error rate.

  4. CWSP Certified Wireless Security Professional Official Study Guide, Exam PW0-204

    CERN Document Server

    Coleman, David D; Harkins, Bryan E

    2010-01-01

    Sybex is now the official publisher for Certified Wireless Network Professional, the certifying vendor for the CWSP program. This guide covers all exam objectives, including WLAN discovery techniques, intrusion and attack techniques, 802.11 protocol analysis. Wireless intrusion-prevention systems implementation, layer 2 and 3 VPNs used over 802.11 networks, and managed endpoint security systems. It also covers enterprise/SMB/SOHO/Public-Network Security design models and security solution implementation, building robust security networks, wireless LAN management systems, and much more.

  5. ANALISA PERFORMANSI VIDEO STREAMING PADA JARINGAN WIRELESS REPEATER BERBASIS TEKNOLOGI 802.11n

    Directory of Open Access Journals (Sweden)

    IGst Ngr PT. Adi S.P.

    2016-12-01

    Full Text Available Penggunaan WLAN sebagai perpanjangan dari infrastruktur kabel LAN yang sudah ada menawarkan kenyamanan mobilitas bagi para pengguna terutama dalam lingkungan bisnis dan perusahaan. Penggunaan WLAN dapat diaplikasikan dalam video streaming dari sisi penerima saat menampilkan media tanpa harus menunggu keseluruhan file data dapat di terima disisi client. Tujuan penelitian ini untuk menunjukkan dampak konfigurasi terhadap traffik QoS video streaming pada jaringan wireless repeater berbasis teknologi 802.11n. Parameter yang dianalisa untuk me-nguji performansi jaringan wireless 802.11n pada topologi wireless repeater yaitu Delay, Jitter, Packet Loss dan Throughput. Sehingga mendapatkan nilai pada skenario di dalam ruangan tidak lebih baik dibandingkan skenario di luar ruangan bila dilihat dari nilai parameter performansi aplikasi video streaming hal tersebut terjadi akibat halangan yang terdapat pada skenario di dalam ruangan dan penurunan kualitas sinyal wifi akibat halangan tersebut.

  6. USMMA LAN -

    Data.gov (United States)

    Department of Transportation — Local Area Network (LAN) includes all personal computers, network servers, network storage, network appliances, network switches, and Internet access to support the...

  7. Implementation and Evaluation of WLAN 802.11ac for Residential Networks in NS-3

    Directory of Open Access Journals (Sweden)

    Andy Bubune Amewuda

    2018-01-01

    Full Text Available Wi-Fi has been an amazingly successful technology. Its success may be attributed to the fact that, despite the significant advances made in technology over the last decade, it has remained backward compatible. 802.11ac is the latest version of the wireless LAN (WLAN standard that is currently being adopted, and it promises to deliver very high throughput (VHT, operating at the 5 GHz band. In this paper, we report on an implementation of 802.11ac wireless LAN for residential scenario based on the 802.11ax task group scenario document. We evaluate the 802.11ac protocol performance under different operating conditions. Key features such as modulation coding set (MCS, frame aggregation, and multiple-input multiple-output (MIMO were investigated. We also evaluate the average throughput, delay, jitter, optimum range for goodput, and effect of station (STA density per access point (AP in a network. ns-3, an open source network simulator with features supporting 802.11ac, was used to perform the simulation. Results obtained indicate that very high data rates are achievable. The highest data rate, the best mean delay, and mean jitter are possible under combined features of 802.11ac (MIMO and A-MPDU.

  8. A Forensic Readiness Model for Wireless Networks

    OpenAIRE

    Ngobeni, Sipho; Venter, Hein; Burke, Ivan

    2010-01-01

    International audience; Over the past decade, wireless mobile communications technology based on IEEE 802.11 wireless local area networks (WLANs) has been adopted worldwide on a massive scale. However, as the number of wireless users has soared, so has the possibility of cyber crime, where criminals deliberately and actively break into WLANs with the intent to cause harm or access sensitive information. WLAN digital forensics is seen not only as a response to cyber crime in wireless environme...

  9. Performance of SON for RSRP-based LTE/WLAN access network selection

    NARCIS (Netherlands)

    Kovács, I.Z.; Laselva, D.; Michaelsen, P.H.; Wang, Y.; Djapic, R.; Spaey, K.

    2014-01-01

    Carrier-grade Wireless Local Area Network (WLAN) is becoming an important complementary system to cellular networks for Mobile Network Operators (MNOs). Network controlled access network selection between cellular and WLAN is an essential functionality to optimize network performance and user

  10. Handover Incentives for Self-Interested WLANs with Overlapping Coverage

    DEFF Research Database (Denmark)

    Fafoutis, Xenofon; Siris, Vasilios A.

    2012-01-01

    We consider an environment where self-interested IEEE 802.11 Wireless Local Area Networks (WLANs) have overlapping coverage, and investigate the incentives that can trigger handovers between the WLANs. Our focus is on the incentives for supporting handovers due solely to the improved performance...... for all wireless networks. Such incentives arise due to a well-known property of 802.11 networks, where low rate users that send traffic significantly degrade the performance of high rate users that are associated with the same access point. A key difference of this paper compared to other works...

  11. A low power Gm-C filter with on-chip automatic tuning for a WLAN transceiver

    International Nuclear Information System (INIS)

    Liu Silin; Ma Heping; Shi Yin

    2010-01-01

    A sixth-order Butterworth Gm-C low-pass filter (LPF) with a continuous tuning architecture has been implemented for a wireless LAN (WLAN) transceiver in 0.35 μm CMOS technology. An interior node scaling technique has been applied directly to the LPF to improve the dynamic range and the structure of the LPF has been optimized to reduce both the die size and the current consumption. Measurement results show that the filter has 77.5 dB dynamic range, 16.3 ns group delay variation, better than 3% cutoff frequency accuracy, and 0 dBm passband IIP3. The whole LPF with the tuning circuit dissipates only 1.42 mA (5 MHz cutoff frequency) or 2.81 mA (10 MHz cutoff frequency) from 2.85 V supply voltage, and only occupies 0.175 mm 2 die size. (semiconductor integrated circuits)

  12. Power-Efficient Communication Protocol for Integrated WWAN and WLAN

    Directory of Open Access Journals (Sweden)

    SuKyoung Lee

    2008-01-01

    Full Text Available One of the most impending requirements to support a seamless communication environment in heterogeneous wireless networks comes from the limited power supply of small-size and low-cost mobile terminals as in stand-alone WLANs or cellular networks. Thus, it is a challenge to design new techniques so that mobile terminals are able to not only maintain their active connection as they move across different types of wireless networks, but also minimize their power consumption. There have been several efforts aimed at having mobile devices equipped with multiple interfaces connect optimally to the access network that minimizes their power consumption. However, a study of existing schemes for WLAN notes that in the idle state, a device with both a WLAN and a WWAN interface needs to keep both interfaces on in order to receive periodic beacon messages from the access point (AP: WLAN and downlink control information from the base station (WWAN, resulting in significant power consumption. Therefore, in this paper, we propose a power-efficient communication protocol (PCP that includes turning off the WLAN interface after it enters the idle state and using the paging channel of WWAN in order to wake up the WLAN interface when there is incoming long-lived multimedia data. This scheme is known to limit the power consumption, while at the same time, it makes use of the paging channel in cellular networks. Further, our proposed scheme is designed to avoid repeatedly turning on and off WLAN interfaces, that consumes a significant amount of power. We propose turning on the WLAN interface when the number of packets in the radio network controller (RNC's buffer reaches a certain threshold level. The tradeoffs between the power saving and the number of packets dropped at the buffer are investigated analytically through the study of an on/off traffic model. Simulation results for scenarios of interest are also provided.

  13. Traffic Regulation on Wireless 802.11 Networks Using Multiple Queue Technique

    Science.gov (United States)

    Dhanal, Radhika J.; Patil, G. A.

    2010-11-01

    WLAN technologies are becoming increasingly popular and are platform for many future applications. IEEE 802.11 Wireless LAN (WLAN) is an excellent solution for the broadband wireless networking. This paper presents a simple approach to enhance the performance of real time (RT) and non-real time (NRT) services over the 802.11 WLAN by using some special queues. This requires the system to first identify the type of service and then use the appropriate scheduling algorithm. The admission control algorithm is used first to determine the admission of particular station. Deficit round robin algorithm is used to set the priorities to RT and NRT packets in order to increase the QoS of WLAN. So we can combine both these algorithms by implementing them one after another. The proposed scheme can improve Voice/Data/Video services through simple software upgrades by reducing the delay, jitter and increasing the throughput. Through simulation, we show that the proposed scheme can give better QoS than existing schemes.

  14. A medical-grade wireless architecture for remote electrocardiography.

    Science.gov (United States)

    Kang, Kyungtae; Park, Kyung-Joon; Song, Jae-Jin; Yoon, Chang-Hwan; Sha, Lui

    2011-03-01

    In telecardiology, electrocardiogram (ECG) signals from a patient are acquired by sensors and transmitted in real time to medical personnel across a wireless network. The use of IEEE 802.11 wireless LANs (WLANs), which are already deployed in many hospitals, can provide ubiquitous connectivity and thus allow cardiology patients greater mobility. However, engineering issues, including the error-prone nature of wireless channels and the unpredictable delay and jitter due to the nondeterministic nature of access to the wireless medium, need to be addressed before telecardiology can be safely realized. We propose a medical-grade WLAN architecture for remote ECG monitoring, which employs the point-coordination function (PCF) for medium access control and Reed-Solomon coding for error control. Realistic simulations with uncompressed two-lead ECG data from the MIT-BIH arrhythmia database demonstrate reliable wireless ECG monitoring; the reliability of ECG transmission exceeds 99.99% with the initial buffering delay of only 2.4 s.

  15. Interference Effects of Blue tooth on WLAN Performance | Okhaifor ...

    African Journals Online (AJOL)

    In this paper, Network stumbler version 0.4.0 was used to estimate the impact of impulsive interference on Wireless Local Area Network (WLAN) when Bluetooth coexist by measuring radiation from a WiFi Access Point (AP) in a homogeneous and heterogeneous scenarios. The parameters measured include Received ...

  16. WLAN steganography revisited

    Science.gov (United States)

    Kraetzer, Christian; Dittmann, Jana; Merkel, Ronny

    2008-02-01

    Two different approaches for using a sequence of packets of the IEEE 802.11 (WLAN) protocol as cover for a stenographic communication can be found in literature: in 2003 Krzysztof Szczypiorski introduced a method constructing a hidden channel using deliberately corrupted WLAN packets for communication. In 2006 Kraetzer et al. introduced a WLAN stenography approach that works without generating corrupted network packets. This later approach, with hidden storage channel scenario (SCI) and the timing channel based scenario (SCII), is reconsidered here. Fixed parameter settings limiting SCIs capabilities in the implementation (already introduced in 2006) motivated an enhancement. The new implementation of SCI increases the capacity, while at the same time improving the reliability and decreasing the detectability in comparison to the work described in 2006. The timing channel based approach SCII from 2006 is in this paper substituted by a completely new design based on the usage of WLAN Access Point addresses for the synchronization and payload transmission. This new design now allows a comprehensive practical evaluation of the implementation and the evaluations of the scheme, which was not possible with the original SCII before. The test results for both enhanced approaches are summarised and compared in terms of detectability, capacity and reliability.

  17. Pre-Authentication Schemes for UMTS-WLAN Interworking

    Directory of Open Access Journals (Sweden)

    Ali Al Shidhani

    2009-01-01

    Full Text Available Interworking Universal Mobile Telecommunication System (UMTS and IEEE 802.11 Wireless Local Area Networks (WLANs introduce new challenges including the design of secured and fast handover protocols. Handover operations within and between networks must not compromise the security of the networks involved. In addition, handovers must be instantaneous to sustain the quality of service (QoS of the applications running on the User Equipment (UE. There is a need to design fast and secured handover protocols to operate in UMTS-WLAN interworking architectures. This paper proposes two secured pre-authentication protocols in the UMTS-WLAN interworking architectures. Performance analysis of the proposed protocols show superior results in comparison to existing protocols in terms of authentication signaling cost, authentication delay and load on critical nodes involved in the authentication procedure. Additionally, the security of the proposed protocols was verified by the Automated Validation of Internet Security Protocols and Applications (AVISPA security analyzer.

  18. An Analysis of Electromagnetic Interference (EMI) of Ultra Wideband(UWB) and IEEE 802.11A Wireless Local Area Network (WLAN) Employing Orthogonal Frequency Division Multiplexing (OFDM)

    Science.gov (United States)

    2004-03-01

    be monitored with an electronic monitoring device that records the ambient temperature periodically. The data is collected and logged daily...Fi) Networking Handbook, McGraw-Hill: NY, 2003. [Sal02]. M.P. Salud , Investigation of RF Emissions from Wireless Networks as a Threat to Avionic

  19. Performance considerations for efficient multimedia streaming in wireless local area networks

    Science.gov (United States)

    Krishnaswamy, Dilip; Stacey, Robert J.; van Alstine, Ryan; Chimitt, William J.

    2004-11-01

    This paper presents investigates multimedia streaming over wireless local area networks. Physical layer sigmoid analytical models are presented for 802.11a/g and for 2x3 MIMO 802.11n MIMO-based systems are presented. Performance results in a wireless LAN environment are presented for traffic using UDP and TCP transport mechanisms. Packet losses are observed in WLAN environments which affects the overall throughput available. Possibilities for performance improvements with the use of 802.11e and MIMO technologies are discussed. System platform architecture performance issues for wireless video conferencing between Intel« PXA27x processor-based handheld platforms are presented and results with retry-limit adaptation are also presented.

  20. Exploiting Spatial Channel Occupancy Information in WLANs

    Science.gov (United States)

    2014-05-15

    described previously, losses in Wireless LANs can be classified into two types: colli - sions, which are the result of unfavorable traffic conditions, and...of simulation time. Dark red is maximum packet length, while blue and green represent shorter packet lengths. The border of the circle represents the...packet lengths tend to be closer to the borders of the topology. This is because these nodes suffer the most from the hidden node problem as well as

  1. Distributed medium access control in wireless networks

    CERN Document Server

    Wang, Ping

    2013-01-01

    This brief investigates distributed medium access control (MAC) with QoS provisioning for both single- and multi-hop wireless networks including wireless local area networks (WLANs), wireless ad hoc networks, and wireless mesh networks. For WLANs, an efficient MAC scheme and a call admission control algorithm are presented to provide guaranteed QoS for voice traffic and, at the same time, increase the voice capacity significantly compared with the current WLAN standard. In addition, a novel token-based scheduling scheme is proposed to provide great flexibility and facility to the network servi

  2. Implementation of DoS attack and mitigation strategies in IEEE 802.11b/g WLAN

    Science.gov (United States)

    Deng, Julia; Meng, Ke; Xiao, Yang; Xu, Roger

    2010-04-01

    IEEE 802.11 wireless Local Area Network (WLAN) becomes very prevalent nowadays. Either as a simple range extender for a home wired Ethernet interface, or as a wireless deployment throughout an enterprise, WLAN provides mobility, convenience, and low cost. However, an IEEE 802.11b/g wireless network uses the frequency of unlicensed 2.4GHz, which makes the network unsafe and more vulnerable than traditional Ethernet networks. As a result, anyone who is familiar with wireless network may initiate a Denial of Service (DoS) attack to influence the common communication of the network or even make it crash. In this paper, we present our studies on the DoS attacks and mitigation strategies for IEEE 802.11b/g WLANs and describe some initial implementations using IEEE 802.11b/g wireless devices.

  3. A Dual-Band Band-Pass Filter with Overlap Step-Impedance and Capacitively Loaded Hairpin Resonators for Wireless LAN Systems

    Directory of Open Access Journals (Sweden)

    P. Chomtong

    2011-01-01

    Full Text Available This paper presents a dual-band band-pass filter using modified cross-coupled step-impedance and capacitively loaded hairpin resonators for WLAN systems. The proposed filter has been designed to operate at a fundamental frequency of 2.4 GHz and the first harmonics frequency of 5.2 GHz. The techniques of step impedance and load capacitor are combined in the design of the proposed filter. In particular, the techniques of modified cross-coupling and overlap resonators are applied to improve the response of insertion losses 21 at the first harmonic frequency of 5.2 GHz. The simulated and experimental results of insertion losses and return losses are better than 3 dB and 20 dB, respectively, at the operating frequencies.

  4. A novel beamforming based model of coverage and transmission costing in IEEE 802.11 WLAN networks

    Directory of Open Access Journals (Sweden)

    Mehdi Guessous

    2017-09-01

    Full Text Available IEEE 802.11 WLAN indoor networks face major inherent and environmental issues such as interference, noise, and obstacles. At the same time, they must provide a maximal service performance in highly changing radio environments and conformance to various applications’ requirements. For this purpose, they require a solid design approach that considers both inputs from the radio interface and the upper-layer services at every design step. The modelization of radio area coverage is a key component in this process and must build on feasible work hypotheses. It should be able also to interpret highly varying characteristics of dense indoor environments, technology advances, service design best practices, end-to-end integration with other network parts: Local Area Network (LAN, Wide Area Network (WAN or Data Center Network (DCN. This work focuses on Radio Resource Management (RRM as a key tool to achieve a solid design in WLAN indoor environments by planning frequency channel assignment, transmit directions and corresponding power levels. Its scope is limited to tackle co-channel interference but can be easily extended to address cross-channel ones. In this paper, we consider beamforming and costing techniques to augment conventional RRM’s Transmit Power Control (TPC procedures that market-leading vendors has implemented and related research has worked on. We present a novel approach of radio coverage modelization and prove its additions to the cited related-work’s models. Our solution model runs three algorithms to evaluate transmission opportunities of Wireless Devices (WD under the coverage area. It builds on realistic hypotheses and a thorough system operation’s understanding to evaluate such an opportunity to transmit, overcomes limitations from compared related-work’s models, and integrates a hierarchical costing system to match Service Level Agreement (SLA expectations. The term “opportunity” in this context relates also to the new

  5. Improved Association and Disassociation Scheme for Enhanced WLAN Handover and VHO

    Directory of Open Access Journals (Sweden)

    Sungjin Shin

    2016-01-01

    Full Text Available The number of mobile devices and wireless connections is significantly increasing. Among many wireless protocol types, wireless local area networks (WLANs are expected to support a significant number of devices. Due to this reason, effective and efficient handover (HO and vertical handover (VHO support for WLAN mobile devices is important. A significant improvement in quality of service (QoS can be obtained by reducing the association and disassociation interruption time for user equipment (UE servicing real-time applications during WLAN HO and VHO operations. Based on this focus, this paper investigates the problem of using only the received signal strength indicator (RSSI in HO and VHO decisions, which is what the current IEEE 802.11 based WLAN systems use. Experimental results presented in this paper demonstrate that only using the RSSI results in significant interruption time during HO to another WLAN access point (AP or to a cellular base station during VHO. Therefore, in this paper, an improved association and disassociation scheme that can reduce the data interruption time (DIT and improve the throughput performance is proposed.

  6. The modelling of a digital forensic readiness approach for wireless local area networks

    CSIR Research Space (South Africa)

    Ngobeni, S

    2012-06-01

    Full Text Available of cybercrime. WLAN digital forensics is seen as not only a response to cybercrime in wireless networks, but also a means to stem the increase of cybercrime in WLANs. The challenge in WLAN digital forensics is to intercept and preserve all the communications...

  7. Data security in wireless local area network

    International Nuclear Information System (INIS)

    Kishk, A.M.A

    2010-01-01

    The ever increasing demand for performance and data security improvement in wireless local area network (W LAN) has motivated increasing the difficulties to crack the system by man-in -the middle attacks. There are two primary and main objectives of this thesis to enhance data security in WLAN. The first objective is the enhancement of identities-exchange and key-exchange during authentication process. The second objective is the investigation of a proposed symmetrical encryption algorithm based on key-updating to enhance the performance of data-security in WLAN. The current asymmetrical encryption algorithms are used to authenticate the devices in WLAN to each other. They are used to exchange the identities and the keys in a secret channel during the authentication process. This thesis investigates the problems of identities- exchange. The enhancement of the identities-exchange and key-exchange stages during the authentication process has been suggested and studied in the thesis to solve the drawbacks of the traditional asymmetrical encryption algorithms.Next the investigation of a proposed symmetrical encryption to encrypt the data during the data exchange process gives a new approach to increase the difficulties to the man in the middle attacks to crack the system.The key updating with each packet is the new approach to solve the problem of the fixed key used to encrypt / decrypt the data with all packets in WLAN.A Comparative study between the proposed symmetrical encryption algorithms and the other algorithms is presented in the thesis. Proposed symmetrical encryption algorithm is applied on a text, voice, and image messages as practical applications of the proposed symmetrical encryption algorithm. Finally, the man-in-the middle attacks can broadcast noise signals in WLAN channels to prevent the data to reach correctly to the end-user. The quality of the received image is measured for the proposed and the traditional symmetrical encryption algorithms to

  8. WiFi Assisted Multi-WiGig AP Coordination for Future Multi-Gbps WLANs

    OpenAIRE

    Mohamed, Ehab Mahmoud; Kusano, Hideyuki; Sakaguchi, Kei; Sampei, Seiichi

    2015-01-01

    Wireless Gigabit (WiGig) access points (APs) using 60 GHz unlicensed frequency band are considered as key enablers for future Gbps wireless local area networks (WLANs). Exhaustive search analog beamforming (BF) is mainly used with WiGig transmissions to overcome channel propagation loss and accomplish high rate data transmissions. Due to its short range transmission with high susceptibility to path blocking, a multiple number of WiGig APs should be installed to fully cover a typical target en...

  9. Exposure assessment of microwave ovens and impact on total exposure in WLANs

    Science.gov (United States)

    Plets, David; Verloock, Leen; Van Den Bossche, Matthias; Tanghe, Emmeric; Joseph, Wout; Martens, Luc

    2016-01-01

    In situ exposure of electric fields of 11 microwave ovens is assessed in an occupational environment and in an office. Measurements as a function of distance without load and with a load of 275 ml of tap water were performed at distances of 1 m, a model of the electric field in a realistic environment is proposed. In an office scenario, switching on a microwave oven increases the median field strength from 91 to 145 mV m−1 (+91 %) in a traditional Wireless Local Area Network (WLAN) deployment and from 44 to 92 mV m−1 (+109 %) in an exposure-optimised WLAN deployment. PMID:25956787

  10. Enhancing LAN performance

    CERN Document Server

    Held, Gilbert

    2004-01-01

    Enhancing LAN Performance, Fourth Edition explains how to connect geographically separated LANs with appropriate bandwidth, the issues to consider when weighing the use of multiport or dualport devices, how to estimate traffic for new networks, the effects of configuration changes on the performance of Ethernet and Token Ring networks, the design of switch-based networks that prevent traffic bottlenecks, and other critical topics. It provides the tools to address these issues in relation to specific network requirements. This volume develops mathematical models of various LAN performance issue

  11. WiGig and IEEE 802.11ad - For multi-gigabyte-per-second WPAN and WLAN

    OpenAIRE

    N., Sai Shankar; Dash, Debashis; Madi, Hassan El; Gopalakrishnan, Guru

    2012-01-01

    The Wireless Gigabit Alliance (WiGig) and IEEE 802.11ad are developing a multigigabit wireless personal and local area network (WPAN/WLAN) specification in the 60 GHz millimeter wave band. Chipset manufacturers, original equipment manufacturers (OEMs), and telecom companies are also assisting in this development. 60 GHz millimeter wave transmission will scale the speed of WLANs and WPANs to 6.75 Gbit/s over distances less than 10 meters. This technology is the first of its kind and will elimi...

  12. The Brave New World of Wireless Technologies: A Primer for Educators.

    Science.gov (United States)

    Boerner, Gerald L.

    2002-01-01

    Discusses the use of wireless local area networks (WLANs) on college campuses. Highlights include traditional wired networks; cost, speed, and reliability; wireless networking standards; mobility; installation speed, simplicity, and flexibility; reduced cost of ownership; scalability; security issues; and a glossary of WLAN terms. (LRW)

  13. An Analysis Of Wireless Security

    OpenAIRE

    Salendra Prasad

    2017-01-01

    The WLAN security includes Wired Equivalent Primary WEP and WI-FI protected Access WPA. Today WEP is regarded as very poor security standard. WEP was regarded as very old security standard and has many security issues which users need to be addressed. In this Paper we will discuss Wireless Security and ways to improve on wireless security.

  14. Physical layer simulation study for the coexistence of WLAN standards

    Energy Technology Data Exchange (ETDEWEB)

    Howlader, M. K. [Marquette Univ., 222 Haggerty Hall, P. O. Box 1881, Milwaukee, WI 53201 (United States); Keiger, C. [Analysis and Measurement Services Corporation, 9111 Cross Park Drive, Knoxville, TN 37923 (United States); Ewing, P. D. [Oak Ridge National Laboratory, MS-6006, P. O. Box 2008, Oak Ridge, TN 37831 (United States); Govan, T. V. [U.S. Nuclear Regulatory Commission, MS T-10-D20, 11545 Rockville Pike, Rockville, MD 20852 (United States)

    2006-07-01

    This paper presents the results of a study on the performance of wireless local area network (WLAN) devices in the presence of interference from other wireless devices. To understand the coexistence of these wireless protocols, simplified physical-layer-system models were developed for the Bluetooth, Wireless Fidelity (WiFi), and Zigbee devices, all of which operate within the 2.4-GHz frequency band. The performances of these protocols were evaluated using Monte-Carlo simulations under various interference and channel conditions. The channel models considered were basic additive white Gaussian noise (AWGN), Rayleigh fading, and site-specific fading. The study also incorporated the basic modulation schemes, multiple access techniques, and channel allocations of the three protocols. This research is helping the U.S. Nuclear Regulatory Commission (NRC) understand the coexistence issues associated with deploying wireless devices and could prove useful in the development of a technical basis for guidance to address safety-related issues with the implementation of wireless systems in nuclear facilities. (authors)

  15. Physical layer simulation study for the coexistence of WLAN standards

    International Nuclear Information System (INIS)

    Howlader, M. K.; Keiger, C.; Ewing, P. D.; Govan, T. V.

    2006-01-01

    This paper presents the results of a study on the performance of wireless local area network (WLAN) devices in the presence of interference from other wireless devices. To understand the coexistence of these wireless protocols, simplified physical-layer-system models were developed for the Bluetooth, Wireless Fidelity (WiFi), and Zigbee devices, all of which operate within the 2.4-GHz frequency band. The performances of these protocols were evaluated using Monte-Carlo simulations under various interference and channel conditions. The channel models considered were basic additive white Gaussian noise (AWGN), Rayleigh fading, and site-specific fading. The study also incorporated the basic modulation schemes, multiple access techniques, and channel allocations of the three protocols. This research is helping the U.S. Nuclear Regulatory Commission (NRC) understand the coexistence issues associated with deploying wireless devices and could prove useful in the development of a technical basis for guidance to address safety-related issues with the implementation of wireless systems in nuclear facilities. (authors)

  16. Wireless network security theories and applications

    CERN Document Server

    Chen, Lei; Zhang, Zihong

    2013-01-01

    Wireless Network Security Theories and Applications discusses the relevant security technologies, vulnerabilities, and potential threats, and introduces the corresponding security standards and protocols, as well as provides solutions to security concerns. Authors of each chapter in this book, mostly top researchers in relevant research fields in the U.S. and China, presented their research findings and results about the security of the following types of wireless networks: Wireless Cellular Networks, Wireless Local Area Networks (WLANs), Wireless Metropolitan Area Networks (WMANs), Bluetooth

  17. AIS Algorithm for Smart Antenna Application in WLAN

    Directory of Open Access Journals (Sweden)

    Evizal Abdul Kadir

    2015-07-01

    Full Text Available Increasing numbers of wireless local area networks (WLAN replacing wired networks have an impact on wireless network systems, causing issues such as interference. The smart antenna system is a method to overcome interference issues in WLANs. This paper proposes an artificial immune system (AIS for a switch beam smart antenna system. A directional antenna is introduced to aim the beam at the desired user. The antenna consists of 8 directional antennas, each of which covers 45 degrees, thus creating an omnidirectional configuration of which the beams cover 360 degrees. To control the beam switching, an inexpensive PIC 16F877 microchip was used. An AIS algorithm was implemented in the microcontroller, which uses the received radio signal strength of the mobile device as reference. This is compared for each of the eight beams, after which the AIS algorithm selects the strongest signal received by the system and the microcontroller will then lock to the desired beam. In the experiment a frequency of 2.4 GHz (ISM band was used for transmitting and receiving. A test of the system was conducted in an outdoor environment. The results show that the switch beam smart antenna worked fine based on locating the mobile device.

  18. WLAN vs. UMTS - The European Scene

    DEFF Research Database (Denmark)

    Tan, Su-En; Saugstrup, Dan; Olesen, Henning

    for further development/deployment of UMTS and WLAN services. More specifically, the paper discusses the technologies of "Voice over IP" (VoIP) and "Mobile over WLAN" through mobile devices, and the quasi-3G technology of EDGE, which could provide some of the same services as UMTS, but at a substantially...

  19. An empirical evaluation of bufferbloat in IEEE 802.11n wireless networks

    KAUST Repository

    Showail, Ahmad

    2014-04-06

    In this paper, we analyze the impact of large, persistently-full buffers (`bufferbloat\\') on various network dynamics in IEEE 802.11n wireless networks. Bufferbloat has mostly been studied in the context of wired networks. We study the impact of bufferbloat on a variety of wireless network topologies, including wireless LAN (WLAN) and multi-hop wireless networks. Our results show that a single FTP transfer between two Linux wireless hosts can saturate the buffers in the network stack, leading to RTT delays exceeding 4.5 s in multi-hop configurations. We show that well-designed Aggregate MAC Protocol Data Unit (A-MPDU) MAC-layer frame aggregation can reduce RTT delays while simultaneously increasing network throughput. However, additional measures may still be required to meet the constraints of real-time flows (such as VoIP). Our experiments show that large buffers can deteriorate the fairness in rate allocation in parking lot based multi-hop networks.

  20. Wireless Communication Technologies

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Wireless Communication Technologies. Since 1999, the wireless LAN has experienced a tremendous growth. Reasons: Adoption of industry standards. Interoperability testing. The progress of wireless equipments to higher data rates. Rapid decrease in product ...

  1. Exploring Processes and Outcomes of Wireless Internet in Higher Education: A Case Study of a University's Early Experience

    Science.gov (United States)

    Lee, Lisa

    2007-01-01

    Many universities in the UK have recently started offering their staff and students free wireless Internet access through Wireless Local Area Network (WLAN) technologies, such as Wi-Fi. Based on a small empirical study of WLAN deployment in a university setting, the article explores adoption processes of the new technology by both the organisation…

  2. A LAN Primer.

    Science.gov (United States)

    Hazari, Sunil I.

    1991-01-01

    Local area networks (LANs) are systems of computers and peripherals connected together for the purposes of electronic mail and the convenience of sharing information and expensive resources. In planning the design of such a system, the components to consider are hardware, software, transmission media, topology, operating systems, and protocols.…

  3. PHAM THI NGOC LAN

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science. PHAM THI NGOC LAN. Articles written in Bulletin of Materials Science. Volume 41 Issue 1 February 2018 pp 6. Lead ions removal from aqueous solution using modified carbon nanotubes · NGUYEN DUC VU QUYEN TRAN NGOC TUYEN DINH QUANG KHIEU HO VAN MINH ...

  4. Multiple Subcarrier Indoor Geolocation System in MIMO-OFDM WLAN APs Structure

    OpenAIRE

    Abdul Hafiizh; Shigeki Obote; Kenichi Kagoshima

    2009-01-01

    This report aims to utilize existing and future Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing Wireless Local Area Network (MIMO-OFDM WLAN) systems characteristics–such as multiple subcarriers, multiple antennas, and channel estimation characteristics–for indoor location estimation systems based on the Direction of Arrival (DOA) and Radio Signal Strength Indication (RSSI) methods. Hybrid of DOA-RSSI methods also evaluated. In the experimental data result, we show th...

  5. Standard Fibre Optic Ring LANs

    Science.gov (United States)

    Beale, N. C. L.

    1985-08-01

    The paper begins with a reminder of the particular need for standards in LANs. We then describe the requirements of High Integrity LANs. Current developments in LAN standards are then outlined. It is argued that the requirements of industrial LANs lead ideally to reconfiguring fibre optic rings, for which there are two major emerging standards. These two (IEEE 802.5 and ANSI FDDI) and the Cambridge Ring are discussed and compared. One implementation - the HILAN is discussed.

  6. WLAN Hot Spot services for the automotive and oil industries. A business analysis

    International Nuclear Information System (INIS)

    Pau, F.; Oremus, M.H.P.

    2003-04-01

    While you refuel for gas, why not refuel for information or download vehicle data? This paper analyzes in extensive detail the user segmentation by vehicle usage, service offering, and full business models from WLAN (Wireless Local Area Network) hot spot services delivered to vehicles (private, professional, public) around gas stations. Also analyzed are the parties which play a role in such service authorization, provisioning and delivery, with all the dependencies modelled by attributed digraphs. Service planning is included as to WLAN base station capabilities. Five year financial models (CAPEX,OPEX), and data pertain to two possible service suppliers: multi-service oil companies, and mobile service operators (or MVNO). Model optimization on the return-on-investment (ROI) is carried out for different deployment scenarios, geographical coverage assumptions, as well as tariff structures. Comparison is also being made with public GPRS data services, as precursors for 3G services, and the effect of WLAN roaming is analyzed. Analysis shows that due to manpower costs and marketing costs, suitable ROI will not be achieved unless externalities are accounted for and innovative tariff structures are introduced. Open issues and further research are outlined. Further work is carried out, also with automotive electronics sector, wireless systems providers, wireless terminals platform suppliers, and vehicle manufacturers

  7. A forensic readiness model for Wireless Local Area Networks

    CSIR Research Space (South Africa)

    Ngobeni, S

    2010-01-01

    Full Text Available Over the past decade, wireless mobile communications technology based on IEEE 802.11 wireless local area networks (WLANs) has been adopted worldwide on a massive scale. However, as the number of wireless users has soared, so has the possibility...

  8. Characterization and Evaluation of a Commercial WLAN System for Human Provocation Studies

    Directory of Open Access Journals (Sweden)

    Norbert Zentai

    2015-01-01

    Full Text Available This work evaluates the complex exposure characteristics of Wireless Local Area Network (WLAN technology and describes the design of a WLAN exposure system built using commercially available modular parts for the study of possible biological health effects due to WLAN exposure in a controlled environment. The system consisted of an access point and a client unit (CU with router board cards types R52 and R52n with 18 dBm and 25 dBm peak power, respectively. Free space radiofrequency field (RF measurements were performed with a field meter at a distance of 40 cm from the CU in order to evaluate the RF exposure at several signal configurations of the exposure system. Finally, the specific absorption rate (SAR generated by the CU was estimated computationally in the head of two human models. Results suggest that exposure to RF fields of WLAN systems strongly depends on the sets of the router configuration: the stability of the exposure was more constant and reliable when both antennas were active and vertically positioned, with best signal quality obtained with the R52n router board at channel 9, in UDP mode. The maximum levels of peak SAR were far away from the limits of international guidelines with peak levels found over the skin.

  9. Ubiquitous and Seamless Localization: Fusing GNSS Pseudoranges and WLAN Signal Strengths

    Directory of Open Access Journals (Sweden)

    Philipp Richter

    2017-01-01

    Full Text Available Ubiquitous global positioning is not feasible by GNSS alone, as it lacks accurate position fixes in dense urban centres and indoors. Hybrid positioning methods have been developed to aid GNSS in those environments. Fingerprinting localization in wireless local area networks (WLANs is a promising aiding system because of its availability, accuracy, and error mechanisms opposed to that of GNSS. This article presents a low-cost approach to ubiquitous, seamless positioning based on a particle filter integrating GNSS pseudoranges and WLAN received signal strength indicators (RSSIs. To achieve accurate location estimates indoors/outdoors and in the transition zones, appropriate likelihood functions are essential as they determine the influence of each sensor information on the position estimate. We model the spatial RSSI distributions with Gaussian processes and use these models to predict RSSIs at the particle’s positions to obtain point estimates of the RSSI likelihood function. The particle filter’s performance is assessed with real data of two test trajectories in an environment challenging for GNSS and WLAN fingerprinting localization. Outcomes of an extended Kalman filter using pseudoranges and a WLAN position as observation is included as benchmark. The proposed algorithm achieves accurate and robust seamless localization with a median accuracy of five meters.

  10. A Low-Power WLAN Communication Scheme for IoT WLAN Devices Using Wake-Up Receivers

    Directory of Open Access Journals (Sweden)

    Hanseul Hong

    2018-01-01

    Full Text Available In this paper, we propose a delay- and power-efficient, multi-user, low-power wireless local area network (WLAN communication scheme for Internet of Things (IoT WLAN devices. Extremely low-power operation is one of the key requirements of emerging IoT devices. However, the current duty-cycle-based power saving approach may incur large access delay times owing to the trade-offs between the power consumption and the access delay. In order to reduce this delay and enhance the power-saving performance, wake-up receiver-based schemes have been proposed. However, because wake-up receiver-based schemes do not consider multiuser operation in dense communication environments, large delays are inevitable in the case of multiuser operation. In order to provide extremely low-power operation and under 1-mW standby power with reduced delay, we employed the optimized multiuser transmission scheduling of IEEE 802.11ax in the proposed scheme and proper enhanced distributed channel access (EDCA parameter settings. This is with the aim to reduce the delay caused by long wake-up times, and to avoid collisions caused by simultaneous transmission in uplink multiuser scenario. By using the proposed scheme, simultaneous IoT communication with multiple mobile IoT devices is possible while providing low-power operation. Simulation results verified the outstanding delay performance of the proposed scheme.

  11. Design control system of telescope force actuators based on WLAN

    Science.gov (United States)

    Shuai, Xiaoying; Zhang, Zhenchao

    2010-05-01

    With the development of the technology of autocontrol, telescope, computer, network and communication, the control system of the modern large and extra lager telescope become more and more complicated, especially application of active optics. Large telescope based on active optics maybe contain enormous force actuators. This is a challenge to traditional control system based on wired networks, which result in difficult-to-manage, occupy signification space and lack of system flexibility. Wireless network can resolve these disadvantages of wired network. Presented control system of telescope force actuators based on WLAN (WFCS), designed the control system framework of WFCS. To improve the performance of real-time, we developed software of force actuators control system in Linux. Finally, this paper discussed improvement of WFCS real-time, conceived maybe improvement in the future.

  12. Fragility issues of medical video streaming over 802.11e-WLAN m-health environments.

    Science.gov (United States)

    Tan, Yow-Yiong Edwin; Philip, Nada; Istepanian, Robert H

    2006-01-01

    This paper presents some of the fragility issues of a medical video streaming over 802.11e-WLAN in m-health applications. In particular, we present a medical channel-adaptive fair allocation (MCAFA) scheme for enhanced QoS support for IEEE 802.11 (WLAN), as a modification for the standard 802.11e enhanced distributed coordination function (EDCF) is proposed for enhanced medical data performance. The medical channel-adaptive fair allocation (MCAFA) proposed extends the EDCF, by halving the contention window (CW) after zeta consecutive successful transmissions to reduce the collision probability when channel is busy. Simulation results show that MCAFA outperforms EDCF in-terms of overall performance relevant to the requirements of high throughput of medical data and video streaming traffic in 3G/WLAN wireless environments.

  13. Double dipole antenna for dual-band wireless local area networks applications

    CSIR Research Space (South Africa)

    Steyn, JM

    2009-09-01

    Full Text Available A double dipole antenna design is proposed for wireless local area network (WLAN) applications. Two parallel dipoles are used to facilitate operation in both the standard WLAN frequency bands (IEEE 802.11b and IEEE 802.11a) simultaneously. The lower...

  14. Point Coordination Function WLAN Traffic Loadings | Ani | Nigerian ...

    African Journals Online (AJOL)

    WLAN's ability to provide high capacity links, mobility and low acquisition cost played considerable positive role in its popularity. The operation of WLAN in ... traffic loadings is presented. Influence of traffic loadings on WLAN quality of service (QoS) parameters was analyzed using computer simulation modeling technique.

  15. From early wireless to Everest.

    Science.gov (United States)

    Allen, A

    1998-01-01

    Medical information has been transmitted using wireless technologies for almost 80 years. A "wired wireless" electronic stethoscope was developed by the U.S. Army Signal Corps in the early 1920's, for potential use in ship-to-shore transmission of cardiac sounds. [Winters SR. Diagnosis by wireless. Scientific American June 11, 1921, p. 465] Today, wireless is used in a wide range of medical applications and at sites from transoceanic air flights to offshore oil platforms to Mt. Everest. 'Wireless LANs' are often used in medical environments. Typically, nurses and physicians in a hospital or clinic use hand-held "wireless thin client" pen computers that exchange patient information and images with the hospital server. Numerous companies, such as Fujitsu (article below) and Cruise Technologies (www.cruisetech.com) manufacture handheld pen-entry computers. One company, LXE, integrates radio-frequency (RF) enhanced hand-held computers specifically designed for production use within a wireless LAN (www.lxe.com). Other companies (Proxim, Symbol, and others) supply the wireless RF LAN infrastructure for the enterprise. Unfortunately, there have been problems with widespread deployment of wireless LANs. Perhaps the biggest impediment has been the lack of standards. Although an international standard (IEEE 802.11) was adopted in 1997, most wireless LAN products still are not compatible with the equipment of competing companies. A problem with the current standard for LAN adapters is that throughput is limited to 3 Mbps--compared to at least 10 Mbps, and often 100 Mbps, in a hard-wired Ethernet LAN. An II Mbps standard is due out in the next year or so, but it will be at least 2 years before standards-compliant products are available. This story profiles some of the ways that wireless is being used to overcome gaps in terrestrial and within-enterprise communication.

  16. Feasibility and Applications of a Wireless Firewall

    OpenAIRE

    Wilhelm, Matthias

    2016-01-01

    Most of today’s wireless communication devices operate on unlicensed bands with uncoordinated spectrum access, with the consequence that RF interference and collisions are impairing the overall performance of wireless networks. In the classical design of network protocols, both packets in a collision are considered lost, such that channel access mechanisms attempt to avoid collisions proactively. However, with the current proliferation of wireless applications, e.g., WLANs, car-to-car network...

  17. Role of LAN in oceanographic information management

    Digital Repository Service at National Institute of Oceanography (India)

    Kunte, P.D.; Bhargava, R.M.S.

    ) LAN and its capabilities, (2) information processing infrastructure at NIO, (3) functioning of INODC and (4) suitability of LAN in increasing efficiency in oceanographic information management. It has been concluded that, LAN can play a very...

  18. _ MULTl-CELL CAMPUS WLAN ENVIRONMENT -

    African Journals Online (AJOL)

    2.0' RELATED WORKS. IEEE 802.11 WLAN Standard. defines only two operational modes in which an MH can operate, namely Active inode. (AM) and Power save mode. (PSM), also known as sleep or dormant mode. In both modes, an NIH stays connected with one of the access points (APs) even when there is no traffic.

  19. Motion sensing using WLAN signal fluctuations

    NARCIS (Netherlands)

    Kavitha Muthukrishnan, K.; Lijding, M.E.M.; Meratnia, Nirvana; Havinga, Paul J.M.

    2006-01-01

    The ability to infer the motion of the user has previously been possible only with the usage of additional hardware. In this paper we show how motion sensing can be obtained just by observing the WLAN radio’s signal strength and its fluctuations. For the first time, we have analyzed the signal

  20. Inferring motion and location using WLAN RSSI

    NARCIS (Netherlands)

    Kavitha Muthukrishnan, K.; van der Zwaag, B.J.; Havinga, Paul J.M.; Fuller, R.; Koutsoukos, X.

    2009-01-01

    We present novel algorithms to infer movement by making use of inherent fluctuations in the received signal strengths from existing WLAN infrastructure. We evaluate the performance of the presented algorithms based on classification metrics such as recall and precision using annotated traces

  1. A GPP-based Software-Defined Radio Front-end for WLAN Standards

    NARCIS (Netherlands)

    Schiphorst, Roelof; Hoeksema, F.W.; Arkesteijn, V.J.; Slump, Cornelis H.; Klumperink, Eric A.M.; Nauta, Bram

    2004-01-01

    This paper presents a software-defined radio testbed for the physical layer of wireless LAN standards. All baseband physical layer functions have been successfully mapped on a Pentium 4 processor that performs these functions in real-time. This has been tested in combination with a CMOS integrated

  2. The Role of Wireless Computing Technology in the Design of Schools.

    Science.gov (United States)

    Nair, Prakash

    This document discusses integrating computers logically and affordably into a school building's infrastructure through the use of wireless technology. It begins by discussing why wireless networks using mobile computers are preferable to desktop machines in each classoom. It then explains the features of a wireless local area network (WLAN) and…

  3. Bandwidth Optimization in Centralized WLANs for Different Traffic Types

    Directory of Open Access Journals (Sweden)

    Haines RJ

    2007-01-01

    Full Text Available Allocating bandwidth between different forms of coexisting traffic (such as web-browsing, streaming, and telephony within a wireless LAN is a challenging and interesting problem. Centralized coordination functions in wireless LANs offer several advantages over distributed approaches, having the benefit of a system overview at the controller, but obtaining a stable configuration of bandwidth allocation for the system is nontrivial. We present, review, and compare different mechanisms to achieve this end, and a number of different means of obtaining the configurations themselves. We describe an analytical model of the system under consideration and present two mathematical approaches to derive solutions for any system configuration and deployment, along with an adaptive feedback-based solution. We also describe a comprehensive simulation-based model for the problem, and a prototype that allows comparison of these approaches. Our investigations demonstrate that a self-adaptive dynamic approach far outperforms any static scheme, and that using a mathematical model to produce the configurations themselves confers several advantages.

  4. Predictable and reliable ECG monitoring over IEEE 802.11 WLANs within a hospital.

    Science.gov (United States)

    Park, Juyoung; Kang, Kyungtae

    2014-09-01

    Telecardiology provides mobility for patients who require constant electrocardiogram (ECG) monitoring. However, its safety is dependent on the predictability and robustness of data delivery, which must overcome errors in the wireless channel through which the ECG data are transmitted. We report here a framework that can be used to gauge the applicability of IEEE 802.11 wireless local area network (WLAN) technology to ECG monitoring systems in terms of delay constraints and transmission reliability. For this purpose, a medical-grade WLAN architecture achieved predictable delay through the combination of a medium access control mechanism based on the point coordination function provided by IEEE 802.11 and an error control scheme based on Reed-Solomon coding and block interleaving. The size of the jitter buffer needed was determined by this architecture to avoid service dropout caused by buffer underrun, through analysis of variations in transmission delay. Finally, we assessed this architecture in terms of service latency and reliability by modeling the transmission of uncompressed two-lead electrocardiogram data from the MIT-BIH Arrhythmia Database and highlight the applicability of this wireless technology to telecardiology.

  5. Aspect Ratio of Receiver Node Geometry based Indoor WLAN Propagation Model

    Science.gov (United States)

    Naik, Udaykumar; Bapat, Vishram N.

    2017-08-01

    This paper presents validation of indoor wireless local area network (WLAN) propagation model for varying rectangular receiver node geometry. The rectangular client node configuration is a standard node arrangement in computer laboratories of academic institutes and research organizations. The model assists to install network nodes for the better signal coverage. The proposed model is backed by wide ranging real time received signal strength measurements at 2.4 GHz. The shadow fading component of signal propagation under realistic indoor environment is modelled with the dependency on varying aspect ratio of the client node geometry. The developed new model is useful in predicting indoor path loss for IEEE 802.11b/g WLAN. The new model provides better performance in comparison to well known International Telecommunication Union and free space propagation models. It is shown that the proposed model is simple and can be a useful tool for indoor WLAN node deployment planning and quick method for the best utilisation of the office space.

  6. A solution of High-precision WLAN positioning based on TDOA and PTP

    Directory of Open Access Journals (Sweden)

    Zhou Junjie

    2016-01-01

    Full Text Available For indoor WLAN positioning it is difficult to achieve decimeter or centimeter-level precision questions, to IEEE1588v2 (PTP precision network clock synchronization technology and the arrival time difference principle (TDOA, combined with non line of sight (NLOS error mitigation techniques ranging research and design a set based on the existing WLAN (IEEE802.11x series of standards device with high precision realtime location solutions. First, build a high-performance software-defined radio network communications platform, for accurate measurement of the radio signal arrival time and is calculated based on TDOA location. Secondly, the use of high-precision clock IEEE1588v2 standard equipment PTPGrand-2100 as a network clock source, through the integrated application of multi-hop latency compensation and asymmetric compensation algorithm to ensure nanosecond clock synchronization between the various WLAN access points (AP accuracy(Experiments show that 1 nanosecond time synchronization error is equivalent to 10 to 30 cm of positioning error. Finally, based NLOS error becomes stability principle, filtered NLOS error and pre-positioned before the data, eliminate the influence of the greatest degree of NLOS error, the time domain error control in wireless ranging 5ns or less to achieve decimeter or more accurately estimate the position. The case can be widely used in mobile Internet, logistics management, mineral exploration, health and other needs of the precise location services (LBS in other industry sectors.

  7. A Low-Profile WLAN Antenna with Inductor and Tuning Stub for Broadband Impedance Matching

    Directory of Open Access Journals (Sweden)

    Woo-Su Kim

    2014-01-01

    Full Text Available This paper presents a low-profile multiband antenna suitable for wireless local area networks (WLANs, using a chip inductor and tuning stub for broadband impedance matching. The proposed antenna is compact 12×10×1 mm3 and covers three bands: 2.4-GHz (2.400–2.484 GHz, 5.2-GHz (5.150–5.350 GHz, and 5.8-GHz (5.725–5.825 GHz. The measured 10-dB bandwidths are 12.0% (2.28–2.57 GHz in the lower band for 2.4-GHz WLANs and 39.1% (4.81–7.15 GHz in the upper band for 5 GHz-WLANs. The measured peak gain of the antenna is between 2.7 and 4.39 dBi and the radiation patterns are omnidirectional.

  8. A CPW-Fed Rectangular Ring Monopole Antenna for WLAN Applications

    Directory of Open Access Journals (Sweden)

    Sangjin Jo

    2014-01-01

    Full Text Available We present a simple coplanar waveguide- (CPW- fed rectangular ring monopole antenna designed for dual-band wireless local area network (WLAN applications. The antenna is based on a simple structure composed of a CPW feed line and a rectangular ring. Dual-band WLAN operation can be achieved by controlling the distance between the rectangular ring and the ground plane of the CPW feed line, as well as the horizontal vertical lengths of the rectangular ring. Simulated and measured data show that the antenna has a compact size of 21.4×59.4 mm2, an impedance bandwidths of 2.21–2.70 GHz and 5.04–6.03 GHz, and a reflection coefficient of less than −10 dB. The antenna also exhibits an almost omnidirectional radiation pattern. This simple compact antenna with favorable frequency characteristics therefore is attractive for applications in dual-band WLAN.

  9. Rate Adaptation Based on Collision Probability for IEEE 802.11 WLANs

    Science.gov (United States)

    Kim, Taejoon; Lim, Jong-Tae

    Nowadays IEEE 802.11 wireless local area networks (WLANs) support multiple transmission rates. To achieve the best performance, transmitting stations adopt the various forms of automatic rate fallback (ARF). However, ARF suffers from severe performance degradation as the number of transmitting stations increases. In this paper, we propose a new rate adaptation scheme which adjusts the ARF's up/down threshold according to the channel contention level. Simulation result shows that the proposed scheme achieves fairly good performance compared with the existing schemes.

  10. PRIMAL: Page Rank-Based Indoor Mapping and Localization Using Gene-Sequenced Unlabeled WLAN Received Signal Strength

    Directory of Open Access Journals (Sweden)

    Mu Zhou

    2015-09-01

    Full Text Available Due to the wide deployment of wireless local area networks (WLAN, received signal strength (RSS-based indoor WLAN localization has attracted considerable attention in both academia and industry. In this paper, we propose a novel page rank-based indoor mapping and localization (PRIMAL by using the gene-sequenced unlabeled WLAN RSS for simultaneous localization and mapping (SLAM. Specifically, first of all, based on the observation of the motion patterns of the people in the target environment, we use the Allen logic to construct the mobility graph to characterize the connectivity among different areas of interest. Second, the concept of gene sequencing is utilized to assemble the sporadically-collected RSS sequences into a signal graph based on the transition relations among different RSS sequences. Third, we apply the graph drawing approach to exhibit both the mobility graph and signal graph in a more readable manner. Finally, the page rank (PR algorithm is proposed to construct the mapping from the signal graph into the mobility graph. The experimental results show that the proposed approach achieves satisfactory localization accuracy and meanwhile avoids the intensive time and labor cost involved in the conventional location fingerprinting-based indoor WLAN localization.

  11. PRIMAL: Page Rank-Based Indoor Mapping and Localization Using Gene-Sequenced Unlabeled WLAN Received Signal Strength.

    Science.gov (United States)

    Zhou, Mu; Zhang, Qiao; Xu, Kunjie; Tian, Zengshan; Wang, Yanmeng; He, Wei

    2015-09-25

    Due to the wide deployment of wireless local area networks (WLAN), received signal strength (RSS)-based indoor WLAN localization has attracted considerable attention in both academia and industry. In this paper, we propose a novel page rank-based indoor mapping and localization (PRIMAL) by using the gene-sequenced unlabeled WLAN RSS for simultaneous localization and mapping (SLAM). Specifically, first of all, based on the observation of the motion patterns of the people in the target environment, we use the Allen logic to construct the mobility graph to characterize the connectivity among different areas of interest. Second, the concept of gene sequencing is utilized to assemble the sporadically-collected RSS sequences into a signal graph based on the transition relations among different RSS sequences. Third, we apply the graph drawing approach to exhibit both the mobility graph and signal graph in a more readable manner. Finally, the page rank (PR) algorithm is proposed to construct the mapping from the signal graph into the mobility graph. The experimental results show that the proposed approach achieves satisfactory localization accuracy and meanwhile avoids the intensive time and labor cost involved in the conventional location fingerprinting-based indoor WLAN localization.

  12. A highly linear power amplifier for WLAN

    International Nuclear Information System (INIS)

    Jin Jie; Shi Jia; Ai Baoli; Zhang Xuguang

    2016-01-01

    A three-stage power amplifier (PA) for WLAN application in 2.4-2.5 GHz is presented. The proposed PA employs an adaptive bias circuit to adjust the operating point of the PA to improve the linearity of the PA. Two methods to short the 2nd harmonic circuit are compared in the area of efficiency and gain of the PA. The PA is taped out in the process of 2 μm InGaP/GaAs HBT and is tested by the evaluation board. The measured results show that 31.5 dB power gain and 29.3 dBm P 1dB with an associated 40.4% power added efficiency (PAE) under the single tone stimulus. Up to 26.5 dBm output power can be achieved with an error vector magnitude (EVM) of lower than 3% under the 64QAM/OFDM WLAN stimulus. (paper)

  13. Dimensioning Method for Conversational Video Applications in Wireless Convergent Networks

    Directory of Open Access Journals (Sweden)

    Raquel Perez Leal

    2007-12-01

    Full Text Available New convergent services are becoming possible, thanks to the expansion of IP networks based on the availability of innovative advanced coding formats such as H.264, which reduce network bandwidth requirements providing good video quality, and the rapid growth in the supply of dual-mode WiFi cellular terminals. This paper provides, first, a comprehensive subject overview as several technologies are involved, such as medium access protocol in IEEE802.11, H.264 advanced video coding standards, and conversational application characterization and recommendations. Second, the paper presents a new and simple dimensioning model of conversational video over wireless LAN. WLAN is addressed under the optimal network throughput and the perspective of video quality. The maximum number of simultaneous users resulting from throughput is limited by the collisions taking place in the shared medium with the statistical contention protocol. The video quality is conditioned by the packet loss in the contention protocol. Both approaches are analyzed within the scope of the advanced video codecs used in conversational video over IP, to conclude that conversational video dimensioning based on network throughput is not enough to ensure a satisfactory user experience, and video quality has to be taken also into account. Finally, the proposed model has been applied to a real-office scenario.

  14. Energy-Efficient Bandwidth Allocation for Multiuser Scalable Video Streaming over WLAN

    Directory of Open Access Journals (Sweden)

    Lafruit Gauthier

    2008-01-01

    Full Text Available Abstract We consider the problem of packet scheduling for the transmission of multiple video streams over a wireless local area network (WLAN. A cross-layer optimization framework is proposed to minimize the wireless transceiver energy consumption while meeting the user required visual quality constraints. The framework relies on the IEEE 802.11 standard and on the embedded bitstream structure of the scalable video coding scheme. It integrates an application-level video quality metric as QoS constraint (instead of a communication layer quality metric with energy consumption optimization through link layer scaling and sleeping. Both energy minimization and min-max energy optimization strategies are discussed. Simulation results demonstrate significant energy gains compared to the state-of-the-art approaches.

  15. Compact Dual-Band Dipole Antenna with Asymmetric Arms for WLAN Applications

    Directory of Open Access Journals (Sweden)

    Chung-Hsiu Chiu

    2014-01-01

    Full Text Available A dual-band dipole antenna that consists of a horn- and a C-shaped metallic arm is presented. Depending on the asymmetric arms, the antenna provides two −10 dB impedance bandwidths of 225 MHz (about 9.2% at 2.45 GHz and 1190 MHz (about 21.6% at 5.5 GHz, respectively. This feature enables it to cover the required bandwidths for wireless local area network (WLAN operation at the 2.4 GHz band and 5.2/5.8 GHz bands for IEEE 802.11 a/b/g standards. More importantly, the compact size (7 mm × 24 mm and good radiating performance of the antenna are profitable to be integrated with wireless communication devices on restricted RF-elements spaces.

  16. Electromagnetic compatibility of WLAN adapters with life-supporting medical devices.

    Science.gov (United States)

    Calcagnini, G; Mattei, E; Censi, F; Triventi, M; Lo Sterzo, R; Marchetta, E; Bartolini, P

    2011-05-01

    This paper investigates the electromagnetic compatibility of 45 critical care medical devices (infusion pumps, defibrillators, monitors, lung ventilators, anesthesia machines and external pacemakers) with various types of wireless local area network (WLAN, IEEE 802.11 b/g, 2.45 GHz, 100 mW) adapters. Interference is evaluated by performing ad-hoc tests according to the ANSI C63.18 recommended practice. The behavior of the devices during the tests was monitored using patient simulators/device testers specific for each device class. Electromagnetic interference cases were observed in three of 45 devices at a maximum distance of 5 cm. In two cases the interference caused malfunctions that may have clinical consequences for the patient. The authors' findings show that the use of these wireless local area network adapters can be considered reasonably safe, although interference may occur if they are operated at very close distance (<10 cm) to the medical devices.

  17. Dual-band dual-polarized array for WLAN applications

    CSIR Research Space (South Africa)

    Steyn, JM

    2009-01-01

    Full Text Available Paper presents a dual-band dual-polarized antenna array design for WLAN applications. Four double-dipole elements are orthogonally interleaved to facilitate operation in both the standard WLAN frequency bands (IEEE 802.11b and IEEE 802.11a...

  18. Research on HFC network broadband access using WLAN technology

    Science.gov (United States)

    Chang, Yuguang; Liu, Deming; Zhang, Shu; Wu, Guangsheng

    2007-11-01

    Current broadband access system such as ADSL can not satisfy the network applications as the development of network services. In this paper, we proposed to use WLAN technology on the HFC network as a terminal broadband access plan. First of all, theoretical analysis is given to support the feasibility of using WLAN technology on the HFC network. Then, transmission experiments and results of the proposed plan are described in this paper. The key point of the plan is to use a WLAN access point device as a modem to modulate the baseband Ethernet signal into 2.4GHz WLAN signal which then be transmitted via coaxial cable(COAX). The experimental results show that the average traffic throughput of the system could reach to approximate 20Mbps which is the theoretical throughput of 802.11g WLAN transmission. And the transmission throughput has no remarkable change no matter there is CATV signal in the system or not. Finally, conclusions are drawn out: The proposed system can work properly. WLAN signal is quite suitable to be transmitted in the coaxial cable. CATV signal and WLAN signal are not interfering with each other in the system. Using WLAN on the existing coaxial cable which has already accessed to thousands of people's home could be a cost-effective plan for broadband access on the HFC network.

  19. A Rectangular Ring, Open-Ended Monopole Antenna with Two Symmetric Strips for WLAN and WiMAX Applications

    Directory of Open Access Journals (Sweden)

    Joong-Han Yoon

    2013-01-01

    Full Text Available A triple-band rectangular ring, open-ended monopole antenna with symmetric L strips for wireless local area network (WLAN/Worldwide Interoperability of Microwave Access (WiMAX applications is proposed. The proposed antenna consists of two symmetric folded arms and L strips. Based on the concept, a prototype of the proposed triple antenna has been designed, fabricated, and tested. The numerical and experimental results demonstrated that the proposed antenna satisfied the −10 dB impedance bandwidth requirement while simultaneously covering the WLAN and WiMAX bands. Furthermore, this paper presented and discussed the 2D radiation patterns and 3D gains according to the results of the experiment. The proposed antenna’s peak gain varied between 2.17 and 4.93 dBi, and its average gain varied between −2.97 and −0.53 dBi.

  20. Wireless Local Area Network (WLAN) Vulnerability Assessment and Security

    Science.gov (United States)

    2005-09-01

    injector) Airsnort (GUI based WEP cracker) Cowpatty (WPA PSK bruteforcer ) Bluetooth Bluesnarfer (Bluesnarf attack) Ghettotooth (Bluetooth scanner...Kandy (Mobile phone tool) Bruteforce Guess-who (SSH bruteforc ) Obiwan III (HTTP bruteforce ) 81 Figure 30 shows a screenshot of the

  1. K-12 Local Network (LAN) Design Guide

    National Research Council Canada - National Science Library

    Horton, Cody

    1998-01-01

    ...) educators preparing to design and implement LANs in K-12 schools and libraries. Data was collected during the implementation of LANs in K-12 schools of the Monterey Peninsula Uniform School District (MPUSD...

  2. Cognitive Radio MAC Protocol for WLAN

    DEFF Research Database (Denmark)

    Zhang, Qi; Fitzek, Frank H.P.; Iversen, Villy Bæk

    2008-01-01

    but opportunistically access any other under-utilized licensed spectrum without a license. The application scenario of C-CSMA/CA is infrastructure BSS (Basic Service Set) WLAN. C-CSMA/CA efficiently exploits the inherent characteristics of CSMA/CA to design distributed cooperative outband sensing to explore spectrum...... hole; moreover, it designs dual inband sensing scheme to detect primary user appearance. Additionally, C-CSMA/CA has the advantage to effectively solve the cognitive radio self-coexistence issues in the overlapping CR BSSs scenario. It also realizes station-based dynamic resource selection...

  3. Data converters for wireless standards

    CERN Document Server

    Shi, Chunlei

    2002-01-01

    Wireless communication is witnessing tremendous growth with proliferation of different standards covering wide, local and personal area networks (WAN, LAN and PAN). The trends call for designs that allow 1) smooth migration to future generations of wireless standards with higher data rates for multimedia applications, 2) convergence of wireless services allowing access to different standards from the same wireless device, 3) inter-continental roaming. This requires designs that work across multiple wireless standards, can easily be reused, achieve maximum hardware share at a minimum power consumption levels particularly for mobile battery-operated devices.

  4. "Reliability Of Fiber Optic Lans"

    Science.gov (United States)

    Code n, Michael; Scholl, Frederick; Hatfield, W. Bryan

    1987-02-01

    Fiber optic Local Area Network Systems are being used to interconnect increasing numbers of nodes. These nodes may include office computer peripherals and terminals, PBX switches, process control equipment and sensors, automated machine tools and robots, and military telemetry and communications equipment. The extensive shared base of capital resources in each system requires that the fiber optic LAN meet stringent reliability and maintainability requirements. These requirements are met by proper system design and by suitable manufacturing and quality procedures at all levels of a vertically integrated manufacturing operation. We will describe the reliability and maintainability of Codenoll's passive star based systems. These include LAN systems compatible with Ethernet (IEEE 802.3) and MAP (IEEE 802.4), and software compatible with IBM Token Ring (IEEE 802.5). No single point of failure exists in this system architecture.

  5. Multimedia chatting system on LAN

    Science.gov (United States)

    Lung, Chu-Sheng; Wang, Chun-Chao; Lee, Ching-Long; Huang, Huang-Chen

    1994-04-01

    An interactive system designed for talking via multimedia presentation with other parties on Ethernet- LAN is proposed. Our Multimedia Chatting System will take several media services into consideration, like still image, text, pen writing, voice, and slow-motion video, to integrate a practical chatting system. The prototyping subsystem to implement the above idea is currently under development using NETBIOS communication interface and Microsoft Windows environment.

  6. Preface for the book: Antennas And Propagation for Body-Centric Wireless Communications

    DEFF Research Database (Denmark)

    Frederiksen, Flemming Bjerge; Prasad, Ramjee

    2006-01-01

    The book address the following subjects: Body Centric Wireless Communications possibilities, Electromagnetic properties of the body, On-body Communication Channels at high and low frequency bands, Body Centric UWB Communications, Wearable Antennas for cellular and WLAN communications, Body......-Sensor Networks, Antennas and Propagation for telemedicine and for wireless implants....

  7. Improving Energy Efficiency in Idle Listening of IEEE 802.11 WLANs

    Directory of Open Access Journals (Sweden)

    Muhammad Adnan

    2016-01-01

    Full Text Available This paper aims to improve energy efficiency of IEEE 802.11 wireless local area networks (WLANs by effectively dealing with idle listening (IL, which is required for channel sensing and is unavoidable in a contention-based channel access mechanism. Firstly, we show that IL is a dominant source of energy drain in WLANs and it cannot be effectively alleviated by the power saving mechanism proposed in the IEEE 802.11 standard. To solve this problem, we propose an energy-efficient mechanism that combines three schemes in a systematic way: downclocking, frame aggregation, and contention window adjustment. The downclocking scheme lets a station remain in a semisleep state when overhearing frames destined to neighbor stations, whereby the station consumes the minimal energy without impairing channel access capability. As well as decreasing the channel access overhead, the frame aggregation scheme prolongs the period of semisleep time. Moreover, by controlling the size of contention window based on the number of stations, the proposed mechanism decreases unnecessary IL time due to collision and retransmission. By deriving an analysis model and performing extensive simulations, we confirm that the proposed mechanism significantly improves the energy efficiency and throughput, by up to 2.8 and 1.8 times, respectively, compared to the conventional power saving mechanisms.

  8. WLAN Fingerprint Indoor Positioning Strategy Based on Implicit Crowdsourcing and Semi-Supervised Learning

    Directory of Open Access Journals (Sweden)

    Chunjing Song

    2017-11-01

    Full Text Available Wireless local area network (WLAN fingerprint positioning is an indoor localization technique with high accuracy and low hardware requirements. However, collecting received signal strength (RSS samples for the fingerprint database is time-consuming and labor-intensive, hindering the use of this technique. The popular crowdsourcing sampling technique has been introduced to reduce the workload of sample collection, but has two challenges: one is the heterogeneity of devices, which can significantly affect the positioning accuracy; the other is the requirement of users’ intervention in traditional crowdsourcing, which reduces the practicality of the system. In response to these challenges, we have proposed a new WLAN indoor positioning strategy, which incorporates a new preprocessing method for RSS samples, the implicit crowdsourcing sampling technique, and a semi-supervised learning algorithm. First, implicit crowdsourcing does not require users’ intervention. The acquisition program silently collects unlabeled samples, the RSS samples, without information about the position. Secondly, to cope with the heterogeneity of devices, the preprocessing method maps all the RSS values of samples to a uniform range and discretizes them. Finally, by using a large number of unlabeled samples with some labeled samples, Co-Forest, the introduced semi-supervised learning algorithm, creates and repeatedly refines a random forest ensemble classifier that performs well for location estimation. The results of experiments conducted in a real indoor environment show that the proposed strategy reduces the demand for large quantities of labeled samples and achieves good positioning accuracy.

  9. Efficient Transmission of H.264 Video over Multirate IEEE 802.11e WLANs

    Directory of Open Access Journals (Sweden)

    Alnuweiri Hussein

    2008-01-01

    Full Text Available The H.264 video encoding technology, which has emerged as one of the most promising compression standards, offers many new delivery-aware features such as data partitioning. Efficient transmission of H.264 video over any communication medium requires a great deal of coordination between different communication network layers. This paper considers the increasingly popular and widespread 802.11 Wireless Local Area Networks (WLANs and studies different schemes for the delivery of the baseline and extended profiles of H.264 video over such networks. While the baseline profile produces data similar to conventional video technologies, the extended profile offers a partitioning feature that divides video data into three sets with different levels of importance. This allows for the use of service differentiation provided in the WLAN. This paper examines the video transmission performance of the existing contention-based solutions for 802.11e, and compares it to our proposed scheduled access mechanism. It is demonstrated that the scheduled access scheme outperforms contention-based prioritized services of the 802.11e standard. For partitioned video, it is shown that the overhead of partitioning is too high, and better results are achieved if some partitions are aggregated. The effect of link adaptation and multirate operation of the physical layer (PHY is also investigated in this paper.

  10. Flow transfer times in wireless multihop ad hoc networks

    NARCIS (Netherlands)

    Coenen, Tom Johannes Maria; van den Berg, Hans Leo; Boucherie, Richardus J.; Kouvatsos, D.

    2009-01-01

    A flow level model for multihop wireless ad hoc networks is presented in this paper. Using a flow level view, we show the main properties and modeling challenges for ad hoc networks. Considering different scenarios, a multihop WLAN and a serial network with a TCP-like flow control protocol, we

  11. Wireless Network Penetration Testing and Security Auditing

    Directory of Open Access Journals (Sweden)

    Wang Shao-Long

    2016-01-01

    Full Text Available IEEE802.11 wireless wireless networks have security issues that are vulnerable to a variety of attacks. Due to using radio to transport data, attackers can bypass firewalls, sniff sensitive information, intercept packets and send malicious packets. Security auditing and penetration testing is expected to ensure wireless networks security. The contributions of this work are analyzed the vulnerability and types of attacks pertaining to IEEE 802.11 WLAN, performed well known attacks in a laboratory environment to conduct penetration tests to confirm whether our wireless network is hackable or not. WAIDPS is configured as auditing tool to view wireless attacks, such as WEP/WPA/WPA2 cracking, rouge access points, denial of service attack. WAIDPS is designed to detect wireless intrusion with additional features. Penetration testing and auditing will mitigate the risk and threatening to protect WALN.

  12. Comparative Performance Evaluation of TCP Variants in WiMAX (and WLANs Network Configurations

    Directory of Open Access Journals (Sweden)

    Konstantinos Tsiknas

    2012-01-01

    Full Text Available An important application for the IEEE 802.16 technology (also called WiMAX is to provide high-speed access to the Internet where the transmission control protocol (TCP is the core transport protocol. In this paper we study through extensive simulation scenarios the performance characteristics of five representative TCP schemes, namely, TCP New Reno, Vegas, Veno, Westwood, and BIC, in WiMAX (and WLANs networks, under the conditions of correlated wireless errors, asymmetric end-to-end capabilities, and link congestion. The target is to evaluate how the above conditions would affect the TCP congestion control and suggest the best schemes to be employed in WiMAX networks.

  13. A Very Compact and Low Profile UWB Planar Antenna with WLAN Band Rejection.

    Science.gov (United States)

    Syed, Avez; Aldhaheri, Rabah W

    2016-01-01

    A low-cost coplanar waveguide fed compact ultrawideband (UWB) antenna with band rejection characteristics for wireless local area network (WLAN) is proposed. The notch band characteristic is achieved by etching half wavelength C-shaped annular ring slot in the radiating patch. By properly choosing the radius and position of the slot, the notch band can be adjusted and controlled. With an overall size of 18.7 mm × 17.6 mm, the antenna turns out to be one of the smallest UWB antennas with band-notched characteristics. It has a wide fractional bandwidth of 130% (2.9-13.7 GHz) with VSWR antenna is examined by HFSS simulator. A good agreement is found between measured and simulated results indicating that the proposed antenna is well suited for integration into portable devices for UWB applications.

  14. NOVEL SUPER WIDE BAND ANTENNA WITH WLAN/WiMAX BAND REJECTION AND COMPACT SIZE

    Directory of Open Access Journals (Sweden)

    Hadi Baghali

    2014-01-01

    Full Text Available A 25×25×1.6mm3 implementation of a microstrip-fed printed monopole antenna for the future UWB wireless systems application is presented. It has features of possesses band notched function (from 4.88 to 6.07GHz, extremely wide impedance bandwidth (from 2.58 to 18GHz and its compact size. By using a smooth tapering between the semi fractal-shaped patch and the half ellipse-shaped defected ground plane, the wide impedance bandwidth is achieved with ratio bandwidth larger than 6.97:1. Numerical and experimental results are in good agreement and they indicate that the proposed antenna has a measured 2:1 VSWR bandwidth of 149.8%, except the rejected WLAN band.

  15. Fairness analysis of throughput and delay in WLAN environments with channel diversities

    Directory of Open Access Journals (Sweden)

    Fang Shih-Hau

    2011-01-01

    Full Text Available Abstract The article investigates fairness in terms of throughput and packet delays among users with diverse channel conditions due to the mobility and fading effects in IEEE 802.11 WLAN (wireless local area networks environments. From our analytical results, it is shown that 802.11 CSMA/CA can present fairness among hosts with identical link qualities regardless of equal or different data rates applied. Our analytical results further demonstrate that the presence of diverse channel conditions can pose significant unfairness on both throughput and packet delays even with a link adaptation mechanism since the MCSs (modulation and coding schemes available are limited. The simulation results validate the accuracy of our analytical model.

  16. Handover Management for VoWLAN Based on Estimation of AP Queue Length and Frame Retries

    Science.gov (United States)

    Niswar, Muhammad; Kashihara, Shigeru; Tsukamoto, Kazuya; Kadobayashi, Youki; Yamaguchi, Suguru

    Switching a communication path from one Access Point (AP) to another in inter-domain WLANs is a critical challenge for delay-sensitive applications such as Voice over IP (VoIP) because communication quality during handover (HO) is more likely to be deteriorated. To maintain VoIP quality during HO, we need to solve many problems. In particular, in bi-directional communication such as VoIP, an AP becomes a bottleneck with the increase of VoIP calls. As a result, packets queued in the AP buffer may experience a large queuing delay or packet losses due to increase in queue length or buffer overflow, thereby causing the degradation of VoIP quality for the Mobile Nodes (MNs) side. To avoid this degradation, MNs need to appropriately and autonomously execute HO in response to the change in wireless network condition, i.e., the deterioration of wireless link quality and the congestion state at the AP. In this paper, we propose an HO decision strategy considering frame retries, AP queue length, and transmission rate at an MN for maintaining VoIP quality during HO. Through simulation experiments, we then show that our proposed method can maintain VoIP quality during HO by properly detecting the wireless network condition.

  17. Cost Effective RADIUS Authentication for Wireless Clients

    Directory of Open Access Journals (Sweden)

    Alexandru ENACEANU

    2010-12-01

    Full Text Available Network administrators need to keep administrative user information for each network device, but network devices usually support only limited functions for user management. WLAN security is a modern problem that needs to be solved and it requires a lot of overhead especially when applied to corporate wireless networks. Administrators can set up a RADIUS server that uses an external database server to handle authentication, authorization, and accounting for network security issues.

  18. Applicable approach of the wireless technology for Korean nuclear power plants

    International Nuclear Information System (INIS)

    Ko, Do Young; Lee, Soo Ill

    2013-01-01

    Highlights: • To apply wireless technology for Korean NPPs, several stipulations are proposed. • WLAN is proposed as the most appropriate wireless technology for Korean NPPs. • WLAN can be applied to the specific fields except in the control system. • An attitude survey on wireless showed that 94.7% agree with the necessity of wireless. - Abstract: Recently, many nuclear power plants (NPPs) over the world use various types of wireless systems for the advantages. Unfortunately, wireless technologies are not currently installed in any Korean NPPs because it is difficult to solve the negative impact of unexpected outcomes or failures from the influence of the wireless technologies, which is electromagnetic interference and radio-frequency interference (EMI/RFI). Moreover, a lack of desire on the part of Korean nuclear industry to implement it leads to give up benefit from the wireless technologies. To install the wireless technologies with maximum benefit and minimum risk, a systematic approach, which quantify the negative impact and prevent the influence, is essential; therefore, this paper describes an applicable research result on the wireless technology for Korean NPPs based on regulatory guides and current wireless hardware and software technologies. Also, survey on the needs for the wireless technology for Korean nuclear power plants was conducted, because the level of awareness of workers in NPPs regarding wireless technologies is very important issue. In this paper, we propose an applicable system to enhance the applicability for the wireless technology for Korean NPPs. The result based on proposed applicable system shows that wireless local area network (WLAN) is the representative candidate for Korean NPPs, which can be applied to the specific fields of radiation monitoring, voice and data communication, component monitoring and instrumentation, and wireless cameras

  19. Advanced Techniques to Improve the Performance of OFDM Wireless LAN

    Science.gov (United States)

    2004-06-01

    recent years and have found applications in a number of di- verse areas including telephone-line based ADSL links, digital audio and video broadcasting...attention in recent years and have found applications in a number of diverse areas including telephone-line based ADSL links, digital audio and...ADC Analog to Digital Converter ADSL Asymmetric Digital Subscriber Line AP Access Point AWGN Additive White Gaussian Noise BER Bit Error

  20. Assessment of public exposure form WLANs in the west bank Palestine

    International Nuclear Information System (INIS)

    Lahham, Adnan; Sharabati, Afifeh; ALMasri, Hussein

    2017-01-01

    A total of 271 measurements were conducted at 69 different sites including homes, hospitals, educational institutions and other public places to assess the exposure to radiofrequency emission from wireless local area networks (WLANs). Measurements were conducted at different distances from 40 to 10 m from the access points (APs) in real life conditions using Narda SRM3000 selective radiation meter. Three measurements modes were considered at 1 m distance from the AP which are transmit mode, idle mode, and from the client card (laptop computer). All measurements were conducted indoor in the West Bank environment. Power density levels from WLAN systems were found to vary from 0.001 to ∼1.9 μW cm -2 with an average of 0.12 μW cm -2 . Maximum value found was in university environment, while the minimum was found in schools. For one measurement case where the AP was 20 cm far while transmitting large files, the measured power density reached a value of ∼4.5 μW cm -2 . This value is however 221 times below the general public exposure limit recommended by the International Commission on Non-Ionizing Radiation Protection, which was not exceeded in any case. Measurements of power density at 1 m around the laptop resulted in less exposure than the AP in both transmit and idle modes as well. Specific absorption rate for the head of the laptop user was estimated and found to vary from 0.1 to 2 mW/kg. The frequency distribution of measured power densities follows a log-normal distribution which is generally typical in the assessment of exposure resulting from sources of radiofrequency emissions. (authors)

  1. Security aspects of 3G-WLAN interworking

    DEFF Research Database (Denmark)

    Køien, Geir M.

    2003-01-01

    to roaming and mobility support. In short, WLAN systems are great for hot spot coverage, while 3G systems provide global coverage and the necessary network and management infrastructure to cater for security, roaming, and charging requirements. The focus of the article is on security aspects of 3GPP...

  2. Building an SDN enterprise WLAN based on virtual APs

    NARCIS (Netherlands)

    Sequeira, L.; Cruz, J.L. de la; Ruiz-Mas, J.; Saldana, J.; Fernandez-Navajas, J.; Almodovar, J.

    2017-01-01

    In this letter, the development and testing of an open enterprise Wi-Fi solution based on virtual access points (APs), managed by a central WLAN controller is presented. It allows seamless handovers between APs in different channels, maintaining the QoS of real-time services. The potential

  3. Implementation of mobile ip smooth handoff in wireless networks

    International Nuclear Information System (INIS)

    Kayastha, M.; Chowdhry, B.S.; Memon, A.R.

    2002-01-01

    This paper describes implementation of mobile IP services in two separate wireless LANs based on IEEE 802.11b standards, located in two distant buildings of a university campus. The purpose of the project was to achieve smooth hand-off when a mobile node moves between the two LANs. During our experimentation we have identified some of the limitation of IEEE 802.11b that affects mobile 1P smooth hand off. We have also proposed an algorithm to solve this problem when the mobility is within a limited number of separate wireless LANs. (author)

  4. Evaluasi Kinerja IEEE 802.11e HCCA untuk Dukungan QoS pada WLAN Menggunakan NS-2

    Directory of Open Access Journals (Sweden)

    Amry Daulat Gultom

    2014-06-01

    Full Text Available Wireless Local Area Network (WLAN digunakan oleh trafik multimedia yang seharusnya memerlukan persyaratan jaringan yang lebih baik terhadap delay, jitter dan packet losses. IEEE 802.11 Task Group E memperkenalkan perbaikan protokol MAC 802.11, yaitu Hybrid Coordination Function (HCF, yang terdiri dari dua mekanisme akses: Enhanced Distributed Channel Access (EDCA dan HCF Controlled Channel Access (HCCA yang memberikan dukungan Kualitas Layanan/Quality of Service (QoS bagi trafik multimedia. Tujuan dari penelitian ini adalah untuk memahami algoritma protokol MAC IEEE 802.11e HCCA pada jaringan WLAN, dan menganalisis kinerja protokol MAC 802.11e HCCA pada aplikasi multimedia dengan menggunakan metode simulasi pada NS-2. Metrik kinerja yang diukur adalah jitter dan throughput-nya. Hasil penelitian ini menunjukkan bahwa protokol MAC HCCA dapat memberikan jaminan QoS dibanding protokol MAC DCF, dimana jitter HCCA lebih stabil dari pada jitter DCF. Begitupula dengan throughput HCCA yang tidak berubah selama trafik berlangsung, tidak seperti pada DCF yang masih mengalami fluktuasi yang besar.

  5. A flow level model for wireless multihop ad hoc network throughput

    NARCIS (Netherlands)

    Coenen, Tom Johannes Maria; van den Berg, Hans Leo; Boucherie, Richardus J.

    2005-01-01

    A flow level model for multihop wireless ad hoc networks is presented in this paper. Using a flow level view, we show the main properties and modeling challenges for ad hoc networks. Considering different scenarios, a multihop WLAN and a serial network with a TCP-like flow control protocol, we

  6. Advanced Wireless Local Area Networks in the Unlicensed Sub-1GHz ISM-bands

    NARCIS (Netherlands)

    Aust, S.H.

    2014-01-01

    This dissertation addresses the challenges of wireless local area networks (WLANs) that operate in the unlicensed sub-1GHz industrial, scientific, and medical (ISM) band. Frequencies in the 900MHz spectrum enable a wider coverage due to the longer propagation characteristics of the radio waves. To

  7. WLAN-verkon optimointi kotikäyttöön

    OpenAIRE

    Hyökki, Jyri

    2016-01-01

    Opinnäytetyön tavoitteena oli löytää keinoja langattoman lähiverkon (WLAN) suorituskyvyn parantamiseksi kotikäyttöön ja usean käyttäjän WLAN-verkkoon. Opinnäytetyössä esitettyjen tutkimusten ja testien myötä DNA Oy toteuttaa tarvittaessa muutoksia kuluttajatason WLAN-laitteisiin. WLAN-verkkoa tarjoava tukiasema tai reititin sisältää paljon suorituskykyyn vaikuttavia asetuksia, joita ovat kanavan leveyden valinta, kanavan valinta, Airtime Fairness, Band Steering, Beamforming, Beacon Interv...

  8. Modified Cooperative Access with Relay’s Data (MCARD based Directional Antenna for multi-rate WLANs

    Directory of Open Access Journals (Sweden)

    Ahmed Magdy

    2014-03-01

    Full Text Available In this paper, for multi-rate wireless local area networks (WLANs, a modified protocol in Medium Access Control (MAC, called Modified Cooperative Access with Relay’s Data (MCARD based Directional Antenna using half wave length dipole in Uniform Circular Array (UCA topology is proposed. MCARD gives remote stations chance to send their information by using intermediate stations (relays to Access Point (AP at a higher data rate based practical antenna. As can be seen under MCARD, a relay station transmits its information before forwarding information from the source station because it uses directional antenna. Analytical results and simulations show that MCARD can significantly improve system quality of service (QOS in terms of throughput under different channel conditions.

  9. The Combined Effect of Signal Strength and Background Traffic Load on Speech Quality in IEEE 802.11 WLAN

    Directory of Open Access Journals (Sweden)

    P. Pocta

    2011-04-01

    Full Text Available This paper deals with measurements of the combined effect of signal strength and background traffic load on speech quality in IEEE 802.11 WLAN. The ITU-T G.729AB encoding scheme is deployed in this study and the Distributed Internet Traffic Generator (D-ITG is used for the purpose of background traffic generation. The speech quality and background traffic load are assessed by means of the accomplished PESQ algorithm and Wireshark network analyzer, respectively. The results show that background traffic load has a bit higher impact on speech quality than signal strength when both effects are available together. Moreover, background traffic load also partially masks the impact of signal strength. The reasons for those findings are particularly discussed. The results also suggest some implications for designers of wireless networks providing VoIP service.

  10. Middleware de seguridad para el interworking WLAN-IMS

    Directory of Open Access Journals (Sweden)

    Oscar Caicedo

    2010-01-01

    Full Text Available El 3GPP plantea una arquitectura de seguridad para el interworking WLAN-3GPP, sin embargo ésta presenta ineficiencias en el procedimiento de autenticación, lo que produce un mayor, consumo de recursos de radio, procesamiento en los dispositivos y retardo en la autenticación. Debido a esto, en este artículo se propone un middleware de seguridad que reduce los pasos en la autenticación del interworking WLAN-3GPP y asegura la señalización SIP entre el equipo de usuario (UE, User Equipment y el Proxy CSCF (P-CSCF, Proxy - Call State Control Function del subsistema multimedia IP (IMS, IP Multimedia Subsystem.

  11. Mobility Models for Next Generation Wireless Networks Ad Hoc, Vehicular and Mesh Networks

    CERN Document Server

    Santi, Paolo

    2012-01-01

    Mobility Models for Next Generation Wireless Networks: Ad Hoc, Vehicular and Mesh Networks provides the reader with an overview of mobility modelling, encompassing both theoretical and practical aspects related to the challenging mobility modelling task. It also: Provides up-to-date coverage of mobility models for next generation wireless networksOffers an in-depth discussion of the most representative mobility models for major next generation wireless network application scenarios, including WLAN/mesh networks, vehicular networks, wireless sensor networks, and

  12. LanDPro: Landscape Dynamics Program

    Science.gov (United States)

    2012-09-18

    forward progress in both areas of research. The focus of this component of LanDPro is on cleared circles, which are roughly circular shaped features...about 1 to 3 m diameter that have a smooth, interior shallow depression either devoid of desert pavement clasts or sparsely covered with clasts

  13. Efficient Closed-Loop Schemes for MIMO-OFDM-Based WLANs

    Directory of Open Access Journals (Sweden)

    Jiang Yi

    2006-01-01

    Full Text Available The single-input single-output (SISO orthogonal frequency-division multiplexing (OFDM systems for wireless local area networks (WLAN defined by the IEEE 802.11a standard can support data rates up to 54 Mbps. In this paper, we consider deploying two transmit and two receive antennas to increase the data rate up to 108 Mbps. Applying our recent multiple-input multiple-output (MIMO transceiver designs, that is, the geometric mean decomposition (GMD and the uniform channel decomposition (UCD schemes, we propose simple and efficient closed-loop MIMO-OFDM designs for much improved performance, compared to the standard singular value decomposition (SVD based schemes as well as the open-loop V-BLAST (vertical Bell Labs layered space-time based counterparts. In the explicit feedback mode, precoder feedback is needed for the proposed schemes. We show that the overhead of feedback can be made very moderate by using a vector quantization method. In the time-division duplex (TDD mode where the channel reciprocity is exploited, our schemes turn out to be robust against the mismatch between the uplink and downlink channels. The advantages of our schemes are demonstrated via extensive numerical examples.

  14. A Very Compact and Low Profile UWB Planar Antenna with WLAN Band Rejection

    Directory of Open Access Journals (Sweden)

    Avez Syed

    2016-01-01

    Full Text Available A low-cost coplanar waveguide fed compact ultrawideband (UWB antenna with band rejection characteristics for wireless local area network (WLAN is proposed. The notch band characteristic is achieved by etching half wavelength C-shaped annular ring slot in the radiating patch. By properly choosing the radius and position of the slot, the notch band can be adjusted and controlled. With an overall size of 18.7 mm × 17.6 mm, the antenna turns out to be one of the smallest UWB antennas with band-notched characteristics. It has a wide fractional bandwidth of 130% (2.9–13.7 GHz with VSWR < 2 and rejecting IEEE 802.11a and HIPERLAN/2 frequency band of 5.1–5.9 GHz. Stable omnidirectional radiation patterns in the H plane with an average gain of 4.4 dBi are obtained. The band-notch mechanism of the proposed antenna is examined by HFSS simulator. A good agreement is found between measured and simulated results indicating that the proposed antenna is well suited for integration into portable devices for UWB applications.

  15. Dual Polarized Monopole Patch Antennas for UWB Applications with Elimination of WLAN Signals

    Directory of Open Access Journals (Sweden)

    P. Kumar

    2016-05-01

    Full Text Available This paper presents the design, fabrication and measurement of dual polarized microstrip patch antennas for ultra wideband (UWB applications with notch at 5-6 GHz band. The proposed antenna rejects the wireless local area network (WLAN signals and work properly in the entire remaining ultra-wideband. Two antennas are designed for two different frequency bands of ultra wideband and both antennas together produce the entire ultra wideband with notch at 5-6 GHz band. The antennas are fed by a 50 coaxial probe and the entire design is optimized using CST Microwave Studio. The bandwidth of 3.1-5 GHz is achieved by the optimized design of Antenna-1 and the bandwidth of 6 -10.6 GHz is achieved by the optimized design of Antenna-2. The bandwidth of the optimized combined antenna is 3.1-10.6 GHz with elimination of the 5-6 GHz band. Both antennas are simulated, developed and measured. The simulated and measured results are presented. The two designed dual polarized antennas i.e. Antenna-1 and Antenna-2 can be used for 3.1-5 GHz band and 6-10.6 GHz band dual polarized applications, respectively, and the combined antenna structure can be used for UWB dual polarized applications with elimination of 5-6 GHz band signals.

  16. COMPACT DUAL-BAND INVERTED L SHAPED MONOPOLE ANTENNA FOR WLAN APPLICATIONS

    Directory of Open Access Journals (Sweden)

    K Sumathi

    2015-12-01

    Full Text Available A highly compact and an optimized design of an Inverted L shaped printed monopole antenna with a simple compact ground plane is proposed. To make the designed antenna suitable for implantation it is embedded in FR-4 substrate and is presented. The antenna is designed for dual-band operation at 2.4GHz and 5.2GHz. It is suitable for Wireless Local Area Network (WLAN applications with return loss (S11 < -10dB. The antenna has two different resonant current paths that support two resonances at 2.44GHz and 5.18GHz (forming an F-shaped structure. The size of the antenna is 32.5mm × 19.6mm × 1.6mm. The antenna design is simulated using the tool Advanced Design System (ADS 2014. This antenna design has good return loss and radiation characteristics in both the required frequency bands. The radiation pattern obtained from the proposed antenna is an Omni directional radiation pattern in the E and H plane over the frequency ranges 2.4GHz and 5.2GHz.

  17. CMOS analog baseband circuitry for an IEEE 802.11 b/g/n WLAN transceiver

    International Nuclear Information System (INIS)

    Gong Zheng; Chu Xiaojie; Shi Yin; Lei Qianqian; Lin Min

    2012-01-01

    An analog baseband circuit for a direct conversion wireless local area network (WLAN) transceiver in a standard 0.13-μm CMOS occupying 1.26 mm 2 is presented. The circuit consists of active-RC receiver (RX) 4th order elliptic lowpass filters(LPFs), transmit (PGAs) with DC offset cancellation (DCOC) servo loops, and on-chip output buffers. The RX baseband gain can be programmed in the range of −11 to 49 dB in 2 dB steps with 50–30.2 nV/√Hz input referred noise (IRN) and a 21 to −41 dBm in-band 3rd order interception point (IIP3). The RX/TX LPF cutoff frequencies can be switched between 5 MHz, 10 MHz, and 20 MHz to fulfill the multimode 802.11b/g/n requirements. The TX baseband gain of the I/Q paths are tuned separately from −1.6 to 0.9 dB in 0.1 dB steps to calibrate TX I/Q gain mismatches. By using an identical integrator based elliptic filter synthesis method together with global compensation applied to the LPF capacitor array, the power consumption of the RX LPF is considerably reduced and the proposed chip draws 26.8 mA/8 mA by the RX/TX baseband paths from a 1.2 V supply. (semiconductor integrated circuits)

  18. CMOS analog baseband circuitry for an IEEE 802.11 b/g/n WLAN transceiver

    Science.gov (United States)

    Zheng, Gong; Xiaojie, Chu; Qianqian, Lei; Min, Lin; Yin, Shi

    2012-11-01

    An analog baseband circuit for a direct conversion wireless local area network (WLAN) transceiver in a standard 0.13-μm CMOS occupying 1.26 mm2 is presented. The circuit consists of active-RC receiver (RX) 4th order elliptic lowpass filters(LPFs), transmit (PGAs) with DC offset cancellation (DCOC) servo loops, and on-chip output buffers. The RX baseband gain can be programmed in the range of -11 to 49 dB in 2 dB steps with 50-30.2 nV/√Hz input referred noise (IRN) and a 21 to -41 dBm in-band 3rd order interception point (IIP3). The RX/TX LPF cutoff frequencies can be switched between 5 MHz, 10 MHz, and 20 MHz to fulfill the multimode 802.11b/g/n requirements. The TX baseband gain of the I/Q paths are tuned separately from -1.6 to 0.9 dB in 0.1 dB steps to calibrate TX I/Q gain mismatches. By using an identical integrator based elliptic filter synthesis method together with global compensation applied to the LPF capacitor array, the power consumption of the RX LPF is considerably reduced and the proposed chip draws 26.8 mA/8 mA by the RX/TX baseband paths from a 1.2 V supply.

  19. Ultrawideband Vivaldi Antenna for DVB-T, WLAN, and WiMAX Applications

    Directory of Open Access Journals (Sweden)

    Dalia M. Elsheakh

    2014-01-01

    Full Text Available Compact Vivaldi patch antenna with a parasitic meander line is presented in this paper. A PIN diode switch is used to connect and disconnect ultrahigh frequency band (UHF with ultrawide bandwidth (UWB. The operating frequencies can be switched among different services, depending on the switching states (ON/OFF to add the lower band when required. This antenna is suitable for portable DVB-T which extended from 450 MHz to 850 MHz receiver applications and the WLAN (Wireless Local Area Network IEEE 802.11b,g (5.1–5.8 GHz frequency bands and WiMAX band (3.3–3.8 GHz. The measured reflection coefficient of the proposed antenna is compared with the simulated one; good agreement is observed. Also, simulated radiation pattern of the antenna is presented. All simulations are carried out using the EM commercial simulator, high frequency structure simulator (HFSS ver.13.

  20. Construction of the NIFS campus information network, NIFS-LAN

    International Nuclear Information System (INIS)

    Tsuda, Kenzo; Yamamoto, Takashi; Kato, Takeo; Nakamura, Osamu; Watanabe, Kunihiko; Watanabe, Reiko; Tsugawa, Kazuko; Kamimura, Tetsuo

    2000-10-01

    The advanced NIFS campus information network, NIFS-LAN, was designed and constructed as an informational infrastructure in 1996, 1997 and 1998 fiscal year. NIFS-LAN was composed of three autonomous clusters classified from research purpose; Research Information cluster, Large Helical Device Experiment cluster and Large-Scale Computer Simulation Research cluster. Many ATM(Asychronous Transfer Mode) switching systems and switching equipments were used for NIFS-LAN. Here, the outline of NIFS-LAN is described. (author)

  1. interference effects of blue ence effects of bluetooth on wlan ence ...

    African Journals Online (AJOL)

    eobe

    network (WPAN) and IEEE 802.11 wirel network (WLAN), both of which support operatio the crowded 2.4-GHz Industrial, Scientific and Med. (ISM) band [2, 14]. Although WLAN (also known as WiFi). (BT) are different technologies and are designed different uses, they often complement each othe personal computers as well ...

  2. Frequency notching applicable to CMOS implementation of WLAN compatible IR-UWB pulse generators

    DEFF Research Database (Denmark)

    Shen, Ming; Mikkelsen, Jan H.; Jiang, Hao

    2012-01-01

    Due to overlapping frequency bands, IEEE 802.11a WLAN and Ultra Wide-Band systems potentially suffer from mutual interference problems. This paper proposes a method for inserting frequency notches into the IR-UWB power spectrum to ensure compatibility with WLAN systems. In contrast to conventional...

  3. SSTL Based Low Power Thermal Efficient WLAN Specific 32bit ALU Design on 28nm FPGA

    DEFF Research Database (Denmark)

    Kalia, Kartik; Pandey, Bishwajeet; Das, Teerath

    2016-01-01

    with consideration of airflow toward hit sink and different frequency on which ALU operate in network processor or any WLAN devices. We have done total power analysis of WLAN operating on different frequencies. We have considered a set of frequencies, which are based on IEEE 802.11 standards. First we did...

  4. The modeling of a digital forensic readiness approach to WLAN digital forensics

    CSIR Research Space (South Africa)

    Ngobeni, S

    2010-01-01

    Full Text Available digital forensics is seen as not only a counterproposal but as a solution to the rapid increase of cyber crime in WLANs. The key issue impacting WLAN digital forensics is that, it is an enormous challenge to intercept and preserve all the communications...

  5. Energy and bandwidth-efficient wireless transmission

    CERN Document Server

    Gao, Wei

    2017-01-01

    This book introduces key modulation and predistortion techniques for approaching energy and spectrum-efficient transmission for wireless communication systems. The book presents a combination of theoretical principles, practical implementations, and actual tests. It focuses on spectrum-efficient modulation and energy-efficient transmission techniques in the portable wireless communication systems, and introduces currently developed and designed RF transceivers in the latest wireless markets. Most materials, design examples, and design strategies used are based on the author’s two decades of work in the digital communication fields, especially in the areas of the digital modulations, demodulations, digital signal processing, and linearization of power amplifiers. The applications of these practical products and equipment cover the satellite communications on earth station systems, microwave communication systems, 2G GSM and 3G WCDMA mobile communication systems, and 802.11 WLAN systems.

  6. Obituary: Howard H. Lanning, 1946-2007

    Science.gov (United States)

    Wade, Richard A.; MacConnell, D. Jack

    2009-01-01

    Howard H. Lanning died 20 December 2007 in Tucson, Arizona. He was a Software Quality Assurance Engineer for the Data Products Program at the National Optical Astronomy Observatory [NOAO] in Tucson, having returned to his native West after twenty years at the Space Telescope Science Institute [STScI] in Baltimore, Maryland. Throughout his career in roles supporting other astronomers, Howard steadily and persistently worked at his own research programs, most notably the identification and study of UV-bright sources in the Sandage Two-Color Survey of the Galactic Plane. Minor planet 2000 QJ248 has been named (61913) Lanning in recognition of his contributions. The son of James Clyde Lanning and Ethel Malan Lanning, Howard was born 26 May 1946, in Brawley, a small community near Calipatria, California. His parents worked for the local school district where his late father was Superintendent of Maintenance and Grounds and his mother was a school principal. After graduating from high school in a class of 52, Howard earned his A.A. degree at Imperial Valley Junior College, majoring in Astronomy and minoring in Mathematics. He completed his A.B. degree in Applied Arts and Sciences at San Diego State University [SDSU] in 1969 with the same major and minor. In 1974, he completed his M.S. in Astronomy at SDSU with a thesis on the period variation of the white-dwarf eclipsing binary BD +16∘516. During his time at SDSU Lanning was a Research Assistant/Observer at the former Hale Observatories, working on the optical identification of X-ray sources under the direction of Allan Sandage. His second refereed paper, the first of several finding lists of UV-bright stars arising from this work, appeared in 1973. Fellow students and faculty remember that he was a self-starter, initiating many observing projects of his own at Mount Laguna Observatory and encouraging others to do the same. For more than a decade Lanning was an observer and night assistant at Mount Wilson Observatory

  7. Subjective Audio Quality over a Secure IEEE 802.11n Draft 2.0 Wireless Local Area Network

    Science.gov (United States)

    2009-03-01

    generated by a G.711 codec and transmission over an IEEE 802.11n draft 2.0 wireless local area network (WLAN). Decline in audio quality due to additional...6 2.5 Real-Time Transport Protocol ...................................................................................8 2.6 Audio Codecs ...Page 1. VoIP Audio Codec Data Rates and Typical MOS

  8. Laboratorio de redes locales EV-LAN

    OpenAIRE

    Usbeck Wandemberg, Carlos; Amadio, Franco

    1993-01-01

    Dado el desarrollo de las redes locales, se hace necesario introducirlas dentro de la didáctica, con el fin de operar en este sector. Las problemáticas enfrentadas cubren aspectos como el conocimiento de los estándares, las topologías de las conexiones y medios de transmisión, el empleo y desarrollo del software en ambiente LAN.

  9. ANALISIS MASALAH KEAMANAN JARINGAN WIRELESS KOMPUTER MENGGUNAKAN CAIN

    Directory of Open Access Journals (Sweden)

    Edy Victor Haryanto

    2014-02-01

    Full Text Available Akhir-akhir ini penggunaan jaringan wireless dalam pembangunnan akses internet pada suatu instansi atau perusahaan sangat pesat. Hal ini karena sistem jaringan wireless lebih efisien dalam pembangunaanya dan juga kefleksibilitasnya karena tanpa penggunaan kabel yang merepotkan. Tetapi jaringan wireless memiliki masalah pada keamanan yaitu pada konfigurasi dan enkripsi yang digunakan. Untuk membantu dalam mencoba tingkat keamanan suatu access point wireless dalam upaya untuk memecahkan permasalahan jaringan, maka dapat digunakan tools yang berfungsi mensniffing paket-paket yang ada pada jaringan yang bernama Cain. Cain dapat menganalalisis protocol di dalam jaringan, selain itu Cain dapat diterapkan pada berbagai interface seperti LAN dan Wireless LAN. Dalam hal menganalisis jaringan Cain memiliki banyak fitur yang sangat baik dan handal dalam penggunaanya.

  10. A Coplanar Waveguide Fed Hexagonal Shape Ultra Wide Band Antenna with WiMAX and WLAN Band Rejection

    Directory of Open Access Journals (Sweden)

    T. Mandal

    2014-12-01

    Full Text Available In this paper, a coplanar waveguide (CPW fed hexagonal shape planar antenna has been considered for ultra-wide band (UWB. This antenna is then modified to obtain dual band rejection. The Wireless Local Area Network (WLAN and Wireless Microwave Access (WiMAX band rejections are realized by symmetrically incorporating a pair of L-shape slots within the ground plane as well as a couple of I-shape stubs inserted on the bottom side of radiating patch. The proposed antenna has stop bands of 5.05-5.92 GHz and 3.19-3.7 GHz while maintaining the wideband performance from 2.88 - 13.71 GHz with reflection coefficient of ≤ -10 dB. The antenna exhibits satisfactory omni-directional radiation characteristics throughout its operating band. The peak gain varies from 2 dB to 6 dB in the entire UWB frequency regions except at the notch bands. Surface current distributions are used to analyze the effects of the L-slot and I-shape stub. The measured group delay has small variation within the operating band except notch bands and hence the proposed antenna may be suitable for UWB applications.

  11. A Study of WLAN Campus in an Educational Establishment

    Directory of Open Access Journals (Sweden)

    Taghareed Abdul-Hameed

    2009-10-01

    Full Text Available the main aim of campus network is to efficiently separate, share and access knowledge among its users. The big demand of such systems of distributed knowledge networks is to be able to handle advanced applications which are the end-user requirements. The main goal of this study is to assess the ability of WLAN campus to dealing with applications request of end users in education establishments and network achievement under different conditions of operation. The study has been conducted in two stages: the first stage was accomplished by conducting a survey, using the Student Village network at Anglia Ruskin University as a case study; the main aim was to determine end-use requirements, gather information about the nature applications running by users and get a view about the likely future applications. The second stage was achieved by conducting experiments to evaluate the WLAN campus network performance under various different scenarios: impact of handover from Access Point (AP to another AP on end-user link performance, network performance in different usage time and network performance in different weather conditions.

  12. Distributed Medium Access Control with SDMA Support for WLANs

    Science.gov (United States)

    Zhou, Sheng; Niu, Zhisheng

    With simultaneous multi-user transmissions, spatial division multiple access (SDMA) provides substantial throughput gain over the single user transmission. However, its implementation in WLANs with contention-based IEEE 802.11 MAC remains challenging. Problems such as coordinating and synchronizing the multiple users need to be solved in a distributed way. In this paper, we propose a distributed MAC protocol for WLANs with SDMA support. A dual-mode CTS responding mechanism is designed to accomplish the channel estimation and user synchronization required for SDMA. We analytically study the throughput performance of the proposed MAC, and dynamic parameter adjustment is designed to enhance the protocol efficiency. In addition, the proposed MAC protocol does not rely on specific physical layer realizations, and can work on legacy IEEE 802.11 equipment with slight software updates. Simulation results show that the proposed MAC outperforms IEEE 802.11 significantly, and that the dynamic parameter adjustment can effectively track the load variation in the network.

  13. CWAP Certified Wireless Analysis Professional Official Study Guide Exam PW0-270

    CERN Document Server

    Westcott, David A; Miller, Ben; Mackenzie, Peter

    2011-01-01

    The official study guide for the Certified Wireless Analysis Professional certification from CWNPFour leading wireless experts thoroughly prepare you for the vendor-neutral CWAP exam administered by CWNP, the industry leader for enterprise Wi-Fi training and certification.  This official study guide not only covers all exam objectives for the CWAP exam, it also prepares you to administer and troubleshoot complex enterprise WLAN environments.Covers all exam objectives for the Certified Wireless Analysis Professional (CWAP) examCovers 802.11 physical (PHY) and 802.11 MAC layer frame formats and

  14. High Speed Fibre Optic Backbone LAN

    Science.gov (United States)

    Tanimoto, Masaaki; Hara, Shingo; Kajita, Yuji; Kashu, Fumitoshi; Ikeuchi, Masaru; Hagihara, Satoshi; Tsuzuki, Shinji

    1987-09-01

    Our firm has developed the SUMINET-4100 series, a fibre optic local area network (LAN), to serve the communications system trunk line needs for facilities, such as steel refineries, automobile plants and university campuses, that require large transmission capacity, and for the backbone networks used in intelligent building systems. The SUMINET-4100 series is already in service in various fields of application. Of the networks available in this series, the SUMINET-4150 has a trunk line speed of 128 Mbps and the multiplexer used for time division multiplexing (TDM) was enabled by designing an ECL-TTL gate array (3000 gates) based custom LSI. The synchronous, full-duplex V.24 and V.3.5 interfaces (SUMINET-2100) are provided for use with general purpose lines. And the IBM token ring network, the SUMINET-3200, designed for heterogeneous PCs and the Ethernet can all be connected to sub loops. Further, the IBM 3270 TCA and 5080 CADAM can be connected in the local mode. Interfaces are also provided for the NTT high-speed digital service, the digital PBX systems, and the Video CODEC system. The built-in loop monitor (LM) and network supervisory processor (NSP) provide management of loop utilization and send loop status signals to the host CPU's network configuration and control facility (NCCF). These built-in functions allow both the computer system and LAN to be managed from a single source at the host. This paper outlines features of the SUMINET-4150 and provides an example of its installation.

  15. 9 Office of Regions and Center Operations LANS -

    Data.gov (United States)

    Department of Transportation — The 9 Office of Regions and Center Operations LANS located at regional offices is the backbone that provides connectivity to systems including servers, workstations,...

  16. Multiband Printed Asymmetric Dipole Antenna for LTE/WLAN Applications

    Directory of Open Access Journals (Sweden)

    Chia-Mei Peng

    2013-01-01

    Full Text Available The ability of a single layer strip fed printed asymmetric dipole antenna, which is composed of top-loading, asymmetric coplanar waveguide (ACPW and stepped-feeding structure, to operate at three wide frequency bands (698~960 MHz, 1710~2620 MHz, and 5150~5850 MHz to cover WLAN and LTE operation has been demonstrated. A prototype of the proposed antenna with 57.5 mm in length, 0.4 mm in thickness, and 5 mm in width is fabricated and experimentally investigated. The experimental results indicate that the VSWR 2.5 : 1 bandwidths achieved were 74.3%, 40.8%, and 18.2% at 700 MHz, 2450 MHz, and 5500 MHz, respectively. Experimental results are shown to verify the validity of theoretical work.

  17. Wireless technology for command control and communications

    Science.gov (United States)

    Lee, C. H.

    1993-09-01

    There are many different views on exactly what is personal communication services (PCS). But the majority agree that 'integrated access,' 'personalized identification,' and 'mobile roaming' are the themes of PCS. Personalized services means that identification is not based on a terminal but instead on a person. PCS will use digital technology, standard procedures, and air interface for universal roaming. This means a tetherless connection through all the infrastructure for voice, data, image, and video services. The intensive development can be divided into the following four areas: digital cellular or digital PCS, wireless data network services (WWAN, WLAN, WPBX), land mobile radio (LMR), and mobile satellite services (MSS). These areas characterize wireless technology in their own perspectives; possible DOD applications will be discussed.

  18. Cross-Layer Adaptive Feedback Scheduling of Wireless Control Systems

    Directory of Open Access Journals (Sweden)

    Jinxiang Dong

    2008-07-01

    Full Text Available There is a trend towards using wireless technologies in networked control systems. However, the adverse properties of the radio channels make it difficult to design and implement control systems in wireless environments. To attack the uncertainty in available communication resources in wireless control systems closed over WLAN, a cross-layer adaptive feedback scheduling (CLAFS scheme is developed, which takes advantage of the co-design of control and wireless communications. By exploiting crosslayer design, CLAFS adjusts the sampling periods of control systems at the application layer based on information about deadline miss ratio and transmission rate from the physical layer. Within the framework of feedback scheduling, the control performance is maximized through controlling the deadline miss ratio. Key design parameters of the feedback scheduler are adapted to dynamic changes in the channel condition. An eventdriven invocation mechanism for the feedback scheduler is also developed. Simulation results show that the proposed approach is efficient in dealing with channel capacity variations and noise interference, thus providing an enabling technology for control over WLAN.

  19. Performance Analysis of IEEE 802.11e (EDCF) and IEEE 802.11(DCF) WLAN Incorporating Different Physical Layer Standards

    Science.gov (United States)

    Sharma, V.; Singh, H.; Malhotra, J.

    2012-12-01

    Medium access coordination function basically implements the distributed coordination function (DCF) which provides support to best effort services but limited to QoS services. Subsequently, a new standard, namely enhanced distributed channel access (EDCA) is reported. The IEEE 802.11e (EDCA) defines MAC procedures to support QoS requirements which specifies distributed contention based access scheme to access the shared wireless media. This paper evaluates the performance of EDCA based IEEE 802.11 WLAN for various access categories (ACs) using OPNET™ Modeller 14.5. Further, the computed results are compared with DCF protocols in terms of QoS parameters. Furthermore, the simulative observation is reported at data rate of 54 Mbps using different physical layer protocols such as IEEE 802.11a/b/g to stumble on the best one to be implemented with EDCF to achieve improved QoS.

  20. Experience of wireless local area network in a radiation oncology department

    Directory of Open Access Journals (Sweden)

    Mandal Abhijit

    2010-01-01

    Full Text Available The aim of this work is to develop a wireless local area network (LAN between different types of users (Radiation Oncologists, Radiological Physicists, Radiation Technologists, etc for efficient patient data management and to made easy the availability of information (chair side to improve the quality of patient care in Radiation Oncology department. We have used mobile workstations (Laptops and stationary workstations, all equipped with wireless-fidelity (Wi-Fi access. Wireless standard 802.11g (as recommended by Institute of Electrical and Electronic Engineers (IEEE, Piscataway, NJ has been used. The wireless networking was configured with the Service Set Identifier (SSID, Media Access Control (MAC address filtering, and Wired Equivalent Privacy (WEP network securities. We are successfully using this wireless network in sharing the indigenously developed patient information management software. The proper selection of the hardware and the software combined with a secure wireless LAN setup will lead to a more efficient and productive radiation oncology department.

  1. The Making of a Sustainable Wireless City? Mapping Public Wi-Fi Access in Shanghai

    Directory of Open Access Journals (Sweden)

    Mingfeng Wang

    2016-01-01

    Full Text Available In the context of the global information economy, ready access to the Internet is critical to a city’s competitiveness, which has prompted a number of cities to launch plans to establish wireless networks. Most literature on the development of wireless cities focuses on cities in Western countries, and few have discussed how Chinese cities have adopted wireless technologies in their urban infrastructure development efforts. This paper examines recent development and spatial distribution of public Wi-Fi access in Shanghai, a leading business hub in China. We mapped Wi-Fi hotspots through the government sponsored “i-Shanghai” project and China Mobile Communications Corporation (CMCC. We find that while telecommunication providers have been proactively deploying WLAN (wireless local area network,a proxy of public Wi-Fi or wireless access hotspots in Shanghai, neither government sponsored WLAN hotspots nor facilities established by CMCC could cover the old traditional neighborhoods in the central city and sub-districts in remote rural areas. We also address the development of a more sustainable wireless city in Shanghai with a particular focus on digital divide and social equity issues.

  2. Resource management for multimedia services in high data rate wireless networks

    CERN Document Server

    Zhang, Ruonan; Pan, Jianping

    2017-01-01

    This brief offers a valuable resource on principles of quality-of-service (QoS) provisioning and the related link-layer resource management techniques for high data-rate wireless networks. The primary emphasis is on protocol modeling and analysis. It introduces media access control (MAC) protocols, standards of wireless local area networks (WLANs), wireless personal area networks (WPANs), and wireless body area networks (WBANs), discussing their key technologies, applications, and deployment scenarios. The main analytical approaches and models for performance analysis of the fundamental resource scheduling mechanisms, including the contention-based, reservation-based, and hybrid MAC, are presented. To help readers understand and evaluate system performance, the brief contains a range of simulation results. In addition, a thorough bibliography provides an additional tool. This brief is an essential resource for engineers, researchers, students, and users of wireless networks.

  3. A Novel Hammer-Shaped UWB Antenna with Triple Notched-Band for Rejecting RLS, WLAN and XSCS bands

    Directory of Open Access Journals (Sweden)

    H. S. Mewara

    2017-10-01

    Full Text Available A novel hammer-shaped UWB printed antenna with triple notched stop bands is presented and fabricated on FR-4 substrate with size of 40×40×1.6 mm3. The proposed antenna is composed of hammer-shaped patch with C-shaped slot, U-shaped slot on feed line, and inverted stepped notch and bevel edges with pair of L-shaped slots in partial ground plane. The fabricated antenna is tested and obtained impedance bandwidth 2.89 ̶ 11.6 GHz with three notched stop bands 3.15 ̶ 3.7 GHz, 5.45 ̶ 6.8 GHz, and 7.5 ̶  8.8 GHz, for radiolocation system (RLS, wireless local area networks (WLAN, and X-band satellite communication system (XSCS bands, respectively. Moreover, the antenna result shows omnidirectional radiation pattern, average gain of 3.10 dBi over the whole UWB band except at the notched frequency bands.

  4. Performance Analysis of a Burst Transmission Mechanism Using Microsleep Operation for Green IEEE 802.11 WLANs

    Directory of Open Access Journals (Sweden)

    Raul Palacios-Trujillo

    2017-07-01

    Full Text Available This paper evaluates the performance of a burst transmission mechanism using microsleep operation to support high energy efficiency in IEEE 802.11 Wireless Local Area Networks (WLANs. This mechanism is an implementation of the IEEE 802.11ac Transmission Opportunity Power Save Mode (TXOP PSM. A device using the TXOP PSM-based mechanism can switch to a low-power sleep state for the time that another device transmits a burst of data frames to a third one. This operation is called microsleep and its feasibility strongly depends on the time and energy consumption that a device incurs in the transitions from and to the sleep state. This paper accounts for the impact of these transitions in the derivation of an analytical model to calculate the energy efficiency of the TXOP PSM-based mechanism under network saturation. Results obtained show that the impact of the transition requirements on the feasibility of microsleep operation can be significant depending on the selected system parameters, although it can be reduced by using burst transmissions. When microsleep operation is feasible, the TXOP PSM-based mechanism can improve the energy efficiency of other legacy mechanisms by up to 424% under high traffic loads.

  5. A 0.13 μm CMOS ΔΣ fractional-N frequency synthesizer for WLAN transceivers

    International Nuclear Information System (INIS)

    Chu Xiaojie; Jia Hailong; Lin Min; Shi Yin; Foster, Dai Fa

    2011-01-01

    A fractional-N frequency synthesizer fabricated in a 0.13 μm CMOS technology is presented for the application of IEEE 802.11 b/g wireless local area network (WLAN) transceivers. A monolithic LC voltage controlled oscillator (VCO) is implemented with an on-chip symmetric inductor. The fractional-N frequency divider consists of a pulse swallow frequency divider and a 3rd-order multistage noise shaping (MASH) ΔΣ modulator with noise-shaped dithering techniques. Measurement results show that in all channels, phase noise of the synthesizer achieves −93 dBc/Hz and −118 dBc/Hz in band and out of band respectively with a phase-frequency detector (PFD) frequency of 20 MHz and a loop bandwidth of 100 kHz. The integrated RMS phase error is no more than 0.8°. The proposed synthesizer consumes 8.4 mW from a 1.2 V supply and occupies an area of 0.86 mm 2 . (semiconductor integrated circuits)

  6. A 0.13 μm CMOS ΔΣ fractional-N frequency synthesizer for WLAN transceivers

    Science.gov (United States)

    Xiaojie, Chu; Hailong, Jia; Min, Lin; Yin, Shi; Foster, Dai Fa

    2011-10-01

    A fractional-N frequency synthesizer fabricated in a 0.13 μm CMOS technology is presented for the application of IEEE 802.11 b/g wireless local area network (WLAN) transceivers. A monolithic LC voltage controlled oscillator (VCO) is implemented with an on-chip symmetric inductor. The fractional-N frequency divider consists of a pulse swallow frequency divider and a 3rd-order multistage noise shaping (MASH) ΔΣ modulator with noise-shaped dithering techniques. Measurement results show that in all channels, phase noise of the synthesizer achieves -93 dBc/Hz and -118 dBc/Hz in band and out of band respectively with a phase-frequency detector (PFD) frequency of 20 MHz and a loop bandwidth of 100 kHz. The integrated RMS phase error is no more than 0.8°. The proposed synthesizer consumes 8.4 mW from a 1.2 V supply and occupies an area of 0.86 mm2.

  7. Adaptive Indoor Positioning Model Based on WLAN-Fingerprinting for Dynamic and Multi-Floor Environments

    Directory of Open Access Journals (Sweden)

    Iyad Husni Alshami

    2017-08-01

    Full Text Available The Global Positioning System demonstrates the significance of Location Based Services but it cannot be used indoors due to the lack of line of sight between satellites and receivers. Indoor Positioning Systems are needed to provide indoor Location Based Services. Wireless LAN fingerprints are one of the best choices for Indoor Positioning Systems because of their low cost, and high accuracy, however they have many drawbacks: creating radio maps is time consuming, the radio maps will become outdated with any environmental change, different mobile devices read the received signal strength (RSS differently, and peoples’ presence in LOS between access points and mobile device affects the RSS. This research proposes a new Adaptive Indoor Positioning System model (called DIPS based on: a dynamic radio map generator, RSS certainty technique and peoples’ presence effect integration for dynamic and multi-floor environments. Dynamic in our context refers to the effects of people and device heterogeneity. DIPS can achieve 98% and 92% positioning accuracy for floor and room positioning, and it achieves 1.2 m for point positioning error. RSS certainty enhanced the positioning accuracy for floor and room for different mobile devices by 11% and 9%. Then by considering the peoples’ presence effect, the error is reduced by 0.2 m. In comparison with other works, DIPS achieves better positioning without extra devices.

  8. Wireless local area network in a prehospital environment

    Directory of Open Access Journals (Sweden)

    Grimes Gary J

    2004-08-01

    Full Text Available Abstract Background Wireless local area networks (WLANs are considered the next generation of clinical data network. They open the possibility for capturing clinical data in a prehospital setting (e.g., a patient's home using various devices, such as personal digital assistants, laptops, digital electrocardiogram (EKG machines, and even cellular phones, and transmitting the captured data to a physician or hospital. The transmission rate is crucial to the applicability of the technology in the prehospital setting. Methods We created two separate WLANs to simulate a virtual local are network environment such as in a patient's home or an emergency room (ER. The effects of different methods of data transmission, number of clients, and roaming among different access points on the file transfer rate were determined. Results The present results suggest that it is feasible to transfer small files such as patient demographics and EKG data from the patient's home to the ER at a reasonable speed. Encryption, user control, and access control were implemented and results discussed. Conclusions Implementing a WLAN in a centrally managed and multiple-layer-controlled access control server is the key to ensuring its security and accessibility. Future studies should focus on product capacity, speed, compatibility, interoperability, and security management.

  9. Wireless networks in industrial environments: state of the art and issues

    OpenAIRE

    Carcelle, Xavier; Dang, Tuan; Devic, Catherine

    2006-01-01

    Wireless is everywhere nowadays and WLAN (i.e. 802.11 standard family) has became used by almost any communications devices in the mass market. The recent achievements in the fields of modulation techniques, such as Spread Spectrum, coding methods, such as Turbocodes, CDMA2000, and frequencies allocation methods, such as OFDM and Frequency Hopping, has pushed the growing uses of reliable and low-cost wireless technologies. Among them the last standards are: IEEE 802.11 family (i.e. WiFi), ...

  10. A Clock Fingerprints-Based Approach for Wireless Transmitter Identification

    Science.gov (United States)

    Zhao, Caidan; Xie, Liang; Huang, Lianfen; Yao, Yan

    Cognitive radio (CR) was proposed as one of the promising solutions for low spectrum utilization. However, security problems such as the primary user emulation (PUE) attack severely limit its applications. In this paper, we propose a clock fingerprints-based authentication approach to prevent PUE attacks in CR networks with the help of curve fitting and classifier. An experimental setup was constructed using the WLAN cards and software radio devices, and the corresponding results show that satisfied identification can be achieved for wireless transmitters.

  11. Wireless Access

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Wireless Access. Wireless connect to the Base station. Easy and Convenient access. Costlier as compared to the wired technology. Reliability challenges. We see it as a complementary technology to the DSL.

  12. An Open Slot Antenna with Bandwidth Extension for WLAN/UWB Applications

    Directory of Open Access Journals (Sweden)

    Jing-Ya Deng

    2015-01-01

    Full Text Available An open slot antenna with extended bandwidth for WLAN and UWB applications is proposed. The radiating structure is composed of a rectangular microstrip patch antenna exciting an L-shaped slot etched on the ground plane. The feed position is optimized to get better impedance match for the higher range of the UWB spectrum, while a step in the slot, realized in the ground plane, is employed to extend the lower limit of the bandwidth so as to cover the 2.4 GHz WLAN frequency band. Using these design solutions the antenna bandwidth is successfully extended to 140% so as to cover both the WLAN and the UWB spectrum.

  13. Spread Spectrum Techniques and their Applications to Wireless Communications

    DEFF Research Database (Denmark)

    Prasad, Ramjee; Cianca, E.

    2005-01-01

    Spread Spectrum (SS) radio communications is on the verge of potentially explosive commercial development An SS-based multiple access, such as CDMA, has been chosen for 3G wireless communications. Other current applications of SS techniues are in Wireless LANs and Satellite Navigation Systems....... However, SS techniques will play an important role also in future wireless applications, mainly combined with other technologies such as epsilon, OFDM, MIMO and UWB. In this paper, after an overview on SS signalling and its advantages, some of the most important techniques based on SS signalling...

  14. ANÁLISIS DE MÁXIMO DESEMPEÑO PARA WLAN OPERANDO A TASAS FIJAS O ADAPTIVAS USANDO EL ESTÁNDAR IEEE 802.11 a/b/g FIXED OR ADAPTIVE RATE MAXIMUM THROUGHPUT ANALYSIS FOR IEEE 802.11 a/b/g WLAN'S

    Directory of Open Access Journals (Sweden)

    Walter Grote H

    2007-12-01

    Full Text Available En este trabajo se presenta un análisis simple, pero efectivo, de desempeño (throughput de redes de área local inalámbricas (WLAN: Wireless Local Area Networks operando bajo la familia de estándares IEEE 802.11 a/b/g. El análisis considera la influencia del tamaño de los paquetes, parámetros de configuración de los dispositivos (uso del protocolo RTS/CTS o acceso básico, tamaño de la ventana de contienda inicial, tasas de transmisión como el efecto del número de dispositivos que conforman la red. El objetivo de este estudio es que los administradores de este tipo de redes puedan estimar los efectos que tiene sobre el desempeño la configuración de los dispositivos de la red. Los resultados obtenidos mediante este análisis constituyen una cota máxima del desempeño de la red, ya que, con el objetivo de evitar un análisis estocástico, se asume ausencia de colisiones e interferencia electromagnética en el canalIn this publication a simple, but effective, throughput analysis for WLANs (Wireless Local Area Networks operating according to the IEEE 802.11 a/b/g family of standards is presented. The influence of data packet sizes, device configuration parameters (RTS/CTS or basic access protocol, initial contention window, transmission rate and the effect of the number of devices of the network are considered. The purpose of this study is to provide network administrators an insight of how network configuration parameters affect network performance. Results of this kind of analysis will provide an upper bound on network performance, since they do not consider the effect of collisions and electromagnetic interference

  15. Proposal and Performance Evaluation of a Multicast Routing Protocol for Wireless Mesh Networks Based on Network Load

    Directory of Open Access Journals (Sweden)

    Kiyotaka Oe

    2015-01-01

    Full Text Available Wireless Mesh Networks (WMNs can provide wide range Wireless Local Area Networks (WLANs area by connecting Access Points (APs of WLANs with each other using radio communications. A routing protocol is very important to keep communication quality over radio multihop communications because radio waves are impacted much by surrounding environment. When we use multiuser shared applications like a video conference and an IP phone, it is predicted that large amount of traffic flows on network. Therefore, we should consider network loads to use these applications. In this paper, we propose a multicast routing protocol for WMNs which considers network loads and hop count. Furthermore, we evaluate performance by simulation. In the simulation results, we show that the proposed protocol has better performance than a conventional protocol (MAODV at high loaded scenario.

  16. Dual Y-Shaped Monopole Antenna for Dual-Band WLAN/WiMAX Operations

    Directory of Open Access Journals (Sweden)

    Huiqing Zhai

    2014-01-01

    Full Text Available A dual-band design of monopole antenna with two coupled Y-shaped strips for WLAN/WiMAX applications is presented. By the introduction of dual Y-shaped strips, two separated impedance bandwidths of 22.4% (3.28~4.10 GHz and 19.2% (4.90~5.94 GHz can be obtained to meet the specifications of the WLAN/WiMAX communication band applications. The proposed antenna is successfully simulated, designed, and measured, demonstrating the matched impedance and good radiation characteristics with an overall dimension of 17.7×26×1 mm3.

  17. PEMBUATAN SYSTEM CORPORATE MESSENGER PADA JARINGAN LAN

    Directory of Open Access Journals (Sweden)

    Lily Puspa Dewi

    2008-01-01

    Full Text Available Corporate messenger is the one of the application that can be used for communication in a local area network. The backgrounds of this topic are needs of sending message process in the LAN. The messages which want to be presented are not only in a text format, but also can be in audio visual format. Computer client will connect to the server. When the connection has been established, the client continued the authentication and started sending message between client and server. Audio and video message sending can be done with peer to peer connection with entering the IP address first from remote user that we want to communicate with. The evaluation of this application was done by using 3 computers and as the result, we found that authentication process can work properly, sending text message was done properly and communication using audio can be heard clearly. In addition to video sending message, we could see directly in remote client. The average time to show the video on remote client is 3.771 seconds. Abstract in Bahasa Indonesia: Corporate messenger merupakan suatu aplikasi yang dapat digunakan untuk berkomunikasi dalam sebuah Local Area Network. Hal ini dilatarbelakangi oleh perlu adanya proses pengiriman pesan secara bersama-sama dalam sebuah Local Area Network. Pesan yang ingin dikomunikasikan tidak hanya berupa teks, tetapi dapat juga menggunakan video maupun audio Komputer client akan melakukan koneksi dengan server. Jika sudah terjadi koneksi dengan server, maka client tersebut akan melanjutkan dengan autentikasi dan kemudian dapat melakukan pengiriman pesan dengan client yang telah terdaftar dalam database server. Pengiriman pesan audio dan video terjadi dengan koneksi peer to peer dengan terlebih dahulu memasukkan IP address dari remote user yang ingin diajak berkomunikasi. Pengujian dilakukan dengan menggunakan tiga buah komputer dan diperoleh bahwa proses autentikasi dapat berjalan dengan baik, pengiriman pesan teks dapat dilakukan

  18. Modern wireless telecommunication technologies and their electromagnetic compatibility with life-supporting equipment.

    Science.gov (United States)

    Wallin, Mats K E B; Marve, Therese; Hakansson, Peter K

    2005-11-01

    Hospitals rely on pagers and ordinary telephones to reach staff members in emergency situations. New telecommunication technologies such as General Packet Radio Service (GPRS), the third generation mobile phone system Universal Mobile Telecommunications System (UMTS), and Wireless Local Area Network (WLAN) might be able to replace hospital pagers if they are electromagnetically compatible with medical devices. In this study, we sought to determine if GPRS, UMTS (Wideband Code Division Multiple Access-Frequency Division Duplex [WCDMA FDD]), and WLAN (IEEE 802.11b) transmitted signals interfere with life-supporting equipment in the intensive care and operating room environment. According to United States standard, ANSI C63.18-1997, laboratory tests were performed on 76 medical devices. In addition, clinical tests during 11 operations and 100 h of intensive care were performed. UMTS and WLAN signals caused little interference. Devices using these technologies can be used safely in critical care areas and during operations, but direct contact between medical devices and wireless communication devices ought to be avoided. In the case of GPRS, at a distance of 50 cm, it caused an older infusion pump to alarm and stop infusing; the pump had to be reset. Also, 10 cases of interference with device displays occurred. GPRS can be used safely at a distance of 1 m. Terminals/cellular phones using these technologies should be allowed without restriction in public areas because the risk of interference is minimal.

  19. Received Signal Strength Recovery in Green WLAN Indoor Positioning System Using Singular Value Thresholding

    Directory of Open Access Journals (Sweden)

    Lin Ma

    2015-01-01

    Full Text Available Green WLAN is a promising technique for accessing future indoor Internet services. It is designed not only for high-speed data communication purposes but also for energy efficiency. The basic strategy of green WLAN is that all the access points are not always powered on, but rather work on-demand. Though powering off idle access points does not affect data communication, a serious asymmetric matching problem will arise in a WLAN indoor positioning system due to the fact the received signal strength (RSS readings from the available access points are different in their offline and online phases. This asymmetry problem will no doubt invalidate the fingerprint algorithm used to estimate the mobile device location. Therefore, in this paper we propose a green WLAN indoor positioning system, which can recover RSS readings and achieve good localization performance based on singular value thresholding (SVT theory. By solving the nuclear norm minimization problem, SVT recovers not only the radio map, but also online RSS readings from a sparse matrix by sensing only a fraction of the RSS readings. We have implemented the method in our lab and evaluated its performances. The experimental results indicate the proposed system could recover the RSS readings and achieve good localization performance.

  20. Incorporating antenna beamswitching technique into drivers for IEEE802.11 WLAN devices

    CSIR Research Space (South Africa)

    Mofolo, M

    2015-11-23

    Full Text Available the beamswitching technique for switched parasitic array (SPA) and electronically steerable parasitic array radiator (ESPAR) antennas in the drivers for IEEE802.11 WLAN devices. The modifications of the open source drivers (ath5k and ath9k) to enable real...

  1. KAJIAN PENGARUH MODERATING KELOMPOK PENGGUNA DALAM PENERIMAAN GSM-WLAN DI KOTA BANDUNG BERDASARKAN MODEL UTAUT

    Directory of Open Access Journals (Sweden)

    Syarif Hidayatulloh

    2016-03-01

    Full Text Available Abstract - The increasing use of the internet is testament to the rapid development of technology. GSM-WLAN is one technology that is manifested by the provider with the aim can hit 3G and 4G technology which requires a very large investment funds for the internet service provider. One of its main objectives is the big cities that became the majority of the largest internet usage in Indonesia, Bandung City region was no exception as the capital of the province and city tours. Therefore please note the acceptance of these technologies in the community. The model that is used to find out the level of acceptance and use of such technology is a Unified Theory of Acceptance and Use of Technology (UTAUT. In this study examined factors that supposedly affects the acceptance and use of technology GSM-WLAN in Bandung. Those factors among other performance expectancy, effort expectancy, social influence, facilitating conditions and price value to account for the contribution of each variable to predict the user's stance on such technology by using user groups as a moderator variable. Data processing method used is a Structural Equation Models (SEM that use software AMOS. The data processing of the obtained results performance expectancy value and price effect on attitudes toward the use of GSM technology-WLAN. While the moderator variable user groups influence on the attitude of the users in using GSM technology WLAN. Keywords: Internet, WLAN, GSM-UTAUT, SEM Abstrak - Penggunaan internet yang semakin meningkatnya merupakan bukti perkembangan teknologi yang sangat pesat. GSM-WLAN merupakan salah satu teknologi yang dihadirkan oleh para provider dengan tujuan dapat menekan penggunaan teknologi 3G dan 4G yang memerlukan innvestasi dana yang sangat besar bagi para penyedia layanan internet. Salah satu sasaran utamanya ialah kota-kota besar yang menjadi mayoritas penggunaan internet terbesar di Indonesia, tidak terkecuali wilayah Kota Bandung sebagai Ibu kota

  2. Corporate planning and LAN information systems as forums

    CERN Document Server

    Sabre, Ru Michael

    1992-01-01

    Corporate Planning and LAN: Information Systems as Forums provides information pertinent to the Forum Information System (FIS), a conceptual basis for all corporate planning. This book presents an information system which, by means of LAN, organizational development style prototyping, and organizational learning utilization, can open communications among managers, executives, owners, and employees in a corporate setting.Organized into 10 chapters, this book begins with an overview of the four phases to the eventual use of the FIS in a corporate setting. This text then explores FIS as part of a

  3. TiTeLAN : Lähiverkon toteutus

    OpenAIRE

    Kallio, Rami

    2012-01-01

    TiTeLAN on TAMKin tietotekniikan koulutusohjelman opiskelijoiden järjestämä verkkopelitapahtuma. Verkkopelitapahtuma on tilaisuus, johon kukin osallistuja tuo mukanaan oman tietokoneensa ja pelaa sillä pelejä lähiverkossa muiden osallistujien kanssa. Verkkopelitapahtuman ideana on tuoda pelaamisesta pitäviä ihmisiä yhteen pitämään hauskaa samanhenkisten ihmisten kanssa. Tämä opinnäytetyö käsittelee TiTeLAN-verkkopelitapahtuman lähiverkon toimintaa. Työn alussa käsitellään verkkotopologian...

  4. Wireless virtualization

    CERN Document Server

    Wen, Heming; Le-Ngoc, Tho

    2013-01-01

    This SpringerBriefs is an overview of the emerging field of wireless access and mobile network virtualization. It provides a clear and relevant picture of the current virtualization trends in wireless technologies by summarizing and comparing different architectures, techniques and technologies applicable to a future virtualized wireless network infrastructure. The readers are exposed to a short walkthrough of the future Internet initiative and network virtualization technologies in order to understand the potential role of wireless virtualization in the broader context of next-generation ubiq

  5. R&D on wireless broadband communication systems: new generation ubiquitous mobile network

    Science.gov (United States)

    Ogawa, Hiroyo

    2007-09-01

    R&D on new generation mobile network has attracted a growing interest over the world on the background of rapid market growth for 2nd and 3rd - generation cellular networks and wireless LANs/MANs. The National Institute of Information and Communications Technology (NICT) has been carried out the New Generation Mobile Network Project from April 2002 to March 2006, and has developed fundamental technologies to enable seamless and secure integration of various wireless access networks such as existing cellular networks, wireless LANs, home networks, intelligent transport systems (ITS), the Beyond-3G (B3G) cellular and other wireless access systems. From April 2006, Ubiquitous Mobile Network project focused on cognitive radio technology and integrated seamless networking technology was started. This paper overviews the achievement and the future plan of these projects.

  6. Wireless Internet

    NARCIS (Netherlands)

    el Zarki, M.; Heijenk, Geert; Lee, Kenneth S.; Bidgoli, H.

    This chapter addresses the topic of wireless Internet, the extension of the wireline Internet architecture to the wireless domain. As such the chapter introduces the reader to the dominant characteristics of the Internet, from its structure to the protocols that control the forwarding of data and

  7. Twentenet: A LAN with message priorities, design and performance considerations

    NARCIS (Netherlands)

    Niemegeers, I.G.M.M.; Vissers, C.A.

    1984-01-01

    This paper discusses design and performance aspects of Twentenet, one of the few implemented LANs which offers a service based on message priorities. The medium access mechanism uses the CSMA/CD principle, however with a deterministic collision resolution method. These characteristics make Twentenet

  8. Interview with Datin Goh Suet Lan on Business Coaching

    Science.gov (United States)

    Nimehchisalem, Vahid

    2016-01-01

    In this article the author writes of having had the pleasure of meeting Datin Goh Suet Lan and one of the key members of her team, Mr. Murali, in the Faculty of Modern Languages and Communication, Universiti Putra Malaysia with three colleagues, Associate Professor Dr. Shamala Paramasivam (who initiated this meeting), Dr. Ilyana Binti Jalaluddin,…

  9. Performance of Wireless Networks in Highly Reflective Rooms with Variable Absorption

    Science.gov (United States)

    2014-09-01

    responsible for the creation of the Open Systems Interconnection ( OSI ) model , which has been a conceptual model that characterizes and standardizes the...media access control (MAC) sublayer of the data-link layer of the OSI model for wireless LANs [1]. Collectively, these are referred to as WiFi. The...WIRELESS NETWORKS IN HIGHLY REFLECTIVE ROOMS WITH VARIABLE ABSORPTION by Aníbal L. Intini September 2014 Thesis Advisor: John Gibson Co

  10. Compact UWB Filtering-Antenna with Controllable WLAN Band Rejection Using Defected Microstrip Structure

    Directory of Open Access Journals (Sweden)

    A. Alhegazi

    2018-04-01

    Full Text Available An ultra-wideband (UWB filtering-antenna with controllable band notch is reported in this paper. The filtering-antenna consists of a modified monopole antenna and defected microstrip structure (DMS. The monopole antenna is modified using microstrip transition in the feedline and block with a triangular-shape slot on each side of the circular patch to produce wider impedance bandwidth with better return loss. The DMS is constructed using U-shaped slot etched on the feedline to provide band notch and remove WLAN band (5.1-5.8 GHz. A switch is employed in the DMS to control the created band notch. The measured results show that the proposed design exhibits a wide impedance bandwidth with controllable WLAN band rejection, realized peak gain of 4.85 dB and omnidirectional radiation pattern. Therefore, the proposed design is suitable for UWB applications.

  11. Space partitioning strategies for indoor WLAN positioning with cascade-connected ANN structures.

    Science.gov (United States)

    Borenović, Miloš; Nešković, Aleksandar; Budimir, Djuradj

    2011-02-01

    Position information in indoor environments can be procured using diverse approaches. Due to the ubiquitous presence of WLAN networks, positioning techniques in these environments are the scope of intense research. This paper explores two strategies for space partitioning when utilizing cascade-connected Artificial Neural Networks (ANNs) structures for indoor WLAN positioning. A set of cascade-connected ANN structures with different space partitioning strategies are compared mutually and to the single ANN structure. The benefits of using cascade-connected ANNs structures are shown and discussed in terms of the size of the environment, number of subspaces and partitioning strategy. The optimal cascade-connected ANN structures with space partitioning show up to 50% decrease in median error and up to 12% decrease in the average error with respect to the single ANN model. Finally, the single ANN and the optimal cascade-connected ANN model are compared against other well-known positioning techniques.

  12. LAN Configuration and Analysis: Projects for the Data Communications and Networking Course

    Science.gov (United States)

    Chen, Fang; Brabston, Mary

    2011-01-01

    We implemented two local area network (LAN) projects in our introductory data communications and networking course. The first project required students to develop a LAN from scratch for a small imaginary organization. The second project required student groups to analyze a LAN for a real world small organization. By allowing students to apply what…

  13. Design of Compact 4 × 4 UWB-MIMO Antenna with WLAN Band Rejection

    Directory of Open Access Journals (Sweden)

    Nguyen Khac Kiem

    2014-01-01

    Full Text Available A compact 4 × 4 UWB-MIMO antenna with rejected WLAN band employing an electromagnetic bandgap (EBG structure is presented in this paper. The MIMO antenna is electrically small (60 mm × 60 mm, printed on a FR4_epoxy substrate with the dielectric constant of 4.4 and a thickness of 1.6 mm. A mushroom-like EBG structure is used to reject the WLAN frequency at 5.5 GHz. In order to reduce the mutual coupling of the antenna elements, a stub structure acting as a bandstop filter is inserted to suppress the effect of the surface current between elements of the proposed antenna. The final design of the MIMO antenna satisfies the return loss requirement of less than −10 dB in a bandwidth ranging from 2.73 GHz to 10.68 GHz, which entirely covers UWB frequency band, which is allocated from 3.1 to 10.6 GHz. The antenna also exhibits a WLAN band-notched performance at the frequency band of 5.36–6.34 GHz while the values of all isolation coefficients are below −15 dB and the correlation coefficient of MIMO antenna is less than −28 dB over the UWB range. A good agreement between simulation and measurement is shown in this context.

  14. Inkjet-Printed Wideband Antenna on Resin-Coated Paper Substrate for Curved Wireless Devices

    KAUST Repository

    Abutarboush, Hattan

    2015-04-28

    A low-cost, inkjet-printed multiband monopole antenna for conformal wireless applications is presented for the first time. The antenna is implemented on a low cost resin coated paper substrate which can be used for conformal devices. The antenna developed here is composed of four branch lines on the radiator and three L-shaped slots on the ground plane that help to generate multiple bands without increasing the size of the antenna. The antenna has a compact size, making it suitable for handheld and wearable wireless devices. Details of the inkjet printing fabrication processes and related issues are presented. The antennas were characterized under flat and bent conditions and the results indicate that the antennas can cover most bands for mobile and wireless applications such as PCS, UMTS, GSM1900 and WLAN

  15. Mobile RFID of Wireless Mesh Network for Intelligent Safety Care System

    Directory of Open Access Journals (Sweden)

    Chwen-Fu Horng

    2009-12-01

    Full Text Available This paper presents the Wi-Fi phone with RFID (Radio frequency identification of student entered the school, via Wireless Access Points (APs of school will transmit MAC address with RFID of Wi-Fi phone to Internet Data Center (IDC for server and then the message exchanged by using GSM (or 3G has been transmitted message (or mail to the mobile user of parents (or client user. The wireless access points support broadcasting multiple SSIDs, each of which can have a different set of security and network setting. The RADIUS server is used to authenticate the Wireless Access Point (AP and mobile nodes. In safety case system, we used the several authentication and encryption options for the WLAN. We will discuss the use of Wi-Fi protected Access (WPA, RFID, IP Security (IPSec, and Secure Socket Layer (SSL, and there are high Quality of service (QoS and performance.

  16. ARHITEKTURA LAN Z NAT, VAROVANIMI VLAN IN WIFI DOSTOPOM

    OpenAIRE

    Mlakar, Jure

    2012-01-01

    Omrežja so postala del našega vsakdana in so prisotna vsepovsod. Poznamo dve vrsti tipičnih omrežij: LAN (Angl. Local Area Network) in WAN (angl. Wide Area Network). LAN omrežja uporabljamo za povezavo računalnikov in drugih mrežnih naprav v omejenem geografskem področju, kot je npr. stanovanjska hiša, šola, laboratorij ali poslovna zgradba. WAN omrežja, se uporabljajo za pokritje večjih geografskih območij (vsako omrežje, ki poteka preko mestnih, regionalnih ali državnih mej). Ta om...

  17. Design and initial deployment of the wireless local area networking infrastructure at Sandia National Laboratories.

    Energy Technology Data Exchange (ETDEWEB)

    Long, John P.; Hamill, Michael J.; Mitchell, M. G.; Miller, Marc M.; Witzke, Edward L.; Wiener, Dallas J

    2006-11-01

    A major portion of the Wireless Networking Project at Sandia National Laboratories over the last few years has been to examine IEEE 802.11 wireless networking for possible use at Sandia and if practical, introduce this technology. This project team deployed 802.11a, b, and g Wireless Local Area Networking at Sandia. This report examines the basics of wireless networking and captures key results from project tests and experiments. It also records project members thoughts and designs on wireless LAN architecture and security issues. It documents some of the actions and milestones of this project, including pilot and production deployment of wireless networking equipment, and captures the team's rationale behind some of the decisions made. Finally, the report examines lessons learned, future directions, and conclusions.

  18. LAN MAP: An Innovative Airborne Light at Night Mapping Project

    Science.gov (United States)

    Craine, Eric R.; Craine, B. L.; Craine, E. M.; Craine, P. R.

    2013-01-01

    Widespread installation of inefficient and misdirected artificial light at night (LAN) has led to increasing concerns about light pollution and its impact, not only on astronomical facilities but larger communities as well. Light pollution impacts scientific research, environmental ecosystems, human health, and quality of life. In recent years, the public policy response to light pollution has included formulation of government codes to regulate lighting design and installation. Various environmental groups now include light pollution among their rallying themes to protest both specific and general developments. The latter efforts are often conducted in the absence of any quantitative data and are frequently charged by emotion rather than reason. To bring some scientific objectivity, and quantitative data, to these discussions, we have developed a suite of tools for simultaneous photometric measurements and temporal monitoring of both local communities and the sky overhead. We have also developed novel protocols for the use of these tools, including a triad of airborne, ground mobile, and ground static photometric surveys. We present a summary of these tools and protocols, with special emphasis on the airborne systems, and discuss baseline and follow-up measurements of LAN environments in the vicinity of numerous observatories in Arizona, the home of the initial LAN MAP surveys.

  19. DATA transmission by 2.4 GHz radio frequency and LAN from Nuclear Power Plant to office

    International Nuclear Information System (INIS)

    Tsuji, Kenji; Masuda, Ryota; Hukui, Takuya

    2011-01-01

    Additional monitoring is occasionally done on suspicious equipment such as pumps, motors, valves and so on, when monitoring parameters are different from normal operation in Nuclear Power Plant. If the suspicious equipment is located in high radiation area, it is hard to arrange for the additional monitoring. So, wireless data transmission system is desired. And maintenance persons desire to watch the additional monitoring data in their office on P.C. We can enable to transfer the desired live data from sensors in NPP to the maintenance person's office, using by ZigBee system connected to LAN. In order to enlarge the operating term, the battery for sensors is switched on or off by the signal related to sleeping function on ZigBee sensor-terminal. (author)

  20. Reconfigurable antenna options for 2.45/5 GHz wireless body area networks in healthcare applications.

    Science.gov (United States)

    Abbas, Syed Muzahir; Ranga, Yogesh; Esselle, Karu P

    2015-01-01

    This paper presents electronically reconfigurable antenna options in healthcare applications. They are suitable for wireless body area network devices operating in the industrial, scientific, and medical (ISM) band at 2.45 GHz and IEEE 802.11 Wireless Local Area Network (WLAN) band at 5 GHz (5.15-5.35 GHz, 5.25-5.35 GHz). Two types of antennas are investigated: Antenna-I has a full ground plane and Antenna-II has a partial ground plane. The proposed antennas provide ISM operation in one mode while in another mode they support 5 GHz WLAN band. Their performance is assessed for body centric wireless communication using a simplified human body model. Antenna sensitivity to the gap between the antenna and the human body is investigated for both modes of each antenna. The proposed antennas exhibit a wide radiation pattern along the body surface to provide wide coverage and their small width (14 mm) makes them suitable for on-body communication in healthcare applications.

  1. On Bandwidth Efficient Modulation for High-Data-Rate Wireless LAN Systems

    Directory of Open Access Journals (Sweden)

    Stolpman Victor

    2002-01-01

    Full Text Available We address the problem of high-data-rate orthogonal frequency division multiplexed (OFDM systems under restrictive bandwidth constraints. Based on recent theoretic results, multiple-input multiple-output (MIMO configurations are best suited for this problem. In this paper, we examine several MIMO configurations suitable for high rate transmission. In all scenarios considered, perfect channel state information (CSI is assumed at the receiver. In constrast, availability of CSI at the transmitter is addressed separately. We show that powerful space-time codes can be developed by combining some simple well-known techniques. In fact, we show that for certain configurations, these space-time MIMO configurations are near optimum in terms of outage capacity as compared to previously published codes. Performance evaluation of these techniques is demonstrated within the IEEE 802.11a framework via Monte Carlo simulations.

  2. Preamble Structure for IEEE 802.11n Wireless LAN System

    Science.gov (United States)

    Aoki, Tsuguhide; Egashira, Yoshimasa; Takeda, Daisuke

    This paper proposes a preamble structure that raises the throughput of the physical layer of a MIMO-OFDM system that complies with IEEE 802.11n. The proposed preamble is based on two important criteria that have not been considered in conventional preamble structures but have an important bearing on realization of IEEE 802.11n. One is backward compatibility with legacy devices, such as IEEE 802.11a or IEEE 802.11g. The other is accurate AGC for MIMO data payload of the packet. Computer simulations and a laboratory test demonstrate that the proposed preamble is superior to the other preambles with respect to those two important criteria. The results were submitted to the task group N under the IEEE 802.11 working group and contributed to development of the current draft of IEEE 802.11n.

  3. Hybrid Polling Method for Direct Link Communication for IEEE 802.11 Wireless LANs

    Directory of Open Access Journals (Sweden)

    Woo-Yong Choi

    2008-10-01

    Full Text Available The direct link communication between STAtions (STAs is one of the techniques to improve the MAC performance of IEEE 802.11 infrastructure networks. For the efficient direct link communication, in the literature, the simultaneous polling method was proposed to allow the multiple direct data communication to be performed simultaneously. However, the efficiency of the simultaneous polling method is affected by the interference condition. To alleviate the problem of the lower polling efficiency with the larger interference range, the hybrid polling method is proposed for the direct link communication between STAs in IEEE 802.11 infrastructure networks. By the proposed polling method, we can integrate the sequential and simultaneous polling methods properly according to the interference condition. Numerical examples are also presented to show the medium access control (MAC performance improvement by the proposed polling method.

  4. Estimating the number of competing terminals without a state variation detector in wireless LAN

    Science.gov (United States)

    Lim, Jaechan; Kim, Taejin; Hong, Daehyoung

    2013-12-01

    Estimating the number of competing terminals n (who wish to transmit a packet at the same time) in the IEEE 802.11 system is important for system throughput performance because optimal back-off window size needs to be selected based on n. Therefore, as a new approach for estimating n, we propose H infinity filter that does not need a state variation detector as opposed to the cases of previously proposed approaches. The state variation detector's flaw is incurring tracking latency in addition to the side effect of increased computational cost. All previously proposed approaches demand the employment of the state variation detector to detect the variation of n in the IEEE 802.11 system. By employing H infinity filter, we show improved throughput performance of the system compared to that of previously proposed approaches (e.g., the Kalman filter and particle filter) based on the improved performance in tracking n. In this paper, we justify the superiority of the proposed approach in the terms of tracking performance, throughput performance, and computational complexity.

  5. Performance Evaluation of Quality of Service in IEEE 802.11e Wireless LANs

    Science.gov (United States)

    Peng, Fei; Leung, Victor C. M.

    There have been many performance studies on the original IEEE 802.11 distributed coordinated function using both simulation and analytical methods. However, the recent IEEE 802.11e standard has not yet been investigated extensively. This paper proposes an accurate analytical model for the enhanced distributed channel access (EDCA), which is the core protocol of 802.11e. The model captures the operations of service differentiation using different contention window (CW) sizes, arbitrary interframe space (AIFS), and transmission opportunity (TXOP) limits in EDCA. Using this model, we derive throughput performance of EDCA access categories differentiated through the above mechanisms. The throughput and collision probability derived by our model are validated by simulation results, which show close agreements with the analytical results. Our model provides a useful tool for evaluating the impact of different parameters on the performance of EDCA service differentiation.

  6. Network coding and evolutionary theory for performance enhancement in wireless cooperative clusters

    DEFF Research Database (Denmark)

    Militano, Leonardo; Fitzek, Frank; Iera, Antonio

    2010-01-01

    , portions of a file to be successively exchanged among all cluster members over wireless local area network (WLAN) links. Besides showing the beneficial effects of cooperation, this paper also focuses on the performance enhancement that can be achieved when using the network coding paradigm, whose...... deployment revealed to be very effective in the depicted scenario. The selection of the nodes acting as sources for file injection into the cluster is a critical aspect for the effectiveness of the whole system. Therefore, the potentialities offered by the evolutionary theory applied to the specific problem...

  7. The Sandblaster Software-Defined Radio Platform for Mobile 4G Wireless Communications

    Directory of Open Access Journals (Sweden)

    V. Surducan

    2009-01-01

    Full Text Available We present a tier 2 Software Defined-Radio platform (SDR, built around the latest Sandbridge Technologies' multithreaded Digital Signal Processor (DSP SB3500, along with the description of major design steps taken to ensure the best radio link and computational performance. This SDR platform is capable of executing 4G wireless communication standards such as WiMAX Wave 2, WLAN 802.11 g, and LTE. Performance results for WiMAX are presented in the conclusion section.

  8. [Research on WiFi-based wireless microscopy on a mobile phone and its application].

    Science.gov (United States)

    Hailan, Jin; Jing, Liu

    2012-11-01

    We proposed and realized a new device that acquires microscopic image wirelessly based on mobile phone and WiFi system. The mobile terminals could record, display and store the image from the far end via the wireless LAN. Using this system, a series of conceptual experiments on monitoring the microscopic images of common objects and liver cancer cells were successfully demonstrated. This system is expected to have important value in the experimental investigations on wirelessly monitoring the cell culture, and small insect etc.

  9. Design of WLAN microstrip antenna for 5.17 - 5.835 GHz

    Science.gov (United States)

    Bugaj, Jarosław; Bugaj, Marek; Wnuk, Marian

    2017-04-01

    This paper presents the project of miniaturized WLAN Antenna made in microstrip technique working at a frequency of 5.17 - 5.835 GHz in 802.11ac IEEE standard. This dual layer antenna is designed on RT/duroid 5870 ROGERS CORPORATION substrate with dielectric constant 2.33 and thickness of 3.175 mm. The antenna parameters such as return loss, VSWR, gain and directivity are simulated and optimized using commercial computer simulation technology microwave studio (CST MWS). The paper presents the results of discussed numerical analysis.

  10. VoIP Capacity Evaluation in IEEE 802.11e WLAN Environment

    OpenAIRE

    Trad, Abdelbasset; Munir, Farukh; Turletti, Thierry; Afifi, Hossam

    2006-01-01

    In this report, we present an analytical model for VoIP capacity in IEEE 802.11e WLAN. We illustrate performance results relative to typical codec rates of G.711 PCM (64 kbit/s), G.729 (8 kbit/s) and G.723 (6.3 kbit/s). G.729 and G.723 allow a greater capacity than G.711 which is constrained by throughput. This greater capacity is at the expense of small quality degradation due to the delay increase since G.729 and G.723 codecs are more delay sensitive than G.711. In our study we analyse the ...

  11. LTE, WiMAX and WLAN network design, optimization and performance analysis

    CERN Document Server

    Korowajczuk, Leonhard

    2011-01-01

    A technological overview of LTE and WiMAX LTE, WiMAX and WLAN Network Design, Optimization and Performance Analysis provides a practical guide to LTE and WiMAX technologies introducing various tools and concepts used within. In addition, topics such as traffic modelling of IP-centric networks, RF propagation, fading, mobility, and indoor coverage are explored; new techniques which increase throughput such as MIMO and AAS technology are highlighted; and simulation, network design and performance analysis are also examined. Finally, in the latter part of the book Korowajczuk gives a step-by-step

  12. Optimizing POF/PCF based optical switch for indoor LAN

    International Nuclear Information System (INIS)

    Bhuiyan, M M I; Rashid, M M; Ahmed, Sayem; Bhuiyan, M; Kajihara, M

    2013-01-01

    For indoor local area network (LAN) the Polymer optical fiber (POF) is mostly appropriate, because of its large core diameter and flexible material. A 1×2 optical switch for indoor LAN using POF and a shape memory alloy (SMA) coil actuator with magnetic latches was successfully fabricated and tested. To achieve switching by the movement of a POF, large displacement is necessary because the core diameter is large (e.g., 0.486mm). A SMA coil actuator is used for large displacement and a magnetic latching system is used for fixing the position of the shifted POF. The insertion loss is 0.40 to 0.50dB and crosstalk is more than 50dB without index-matching oil. Switching speed is less than 1s at a driving current of 80mA. A cycling test was performed 1.4 million times. Polymer clad fiber optical (PCF) switch also fabricated and tasted

  13. A Real-Time GPP Software-Defined Radio Testbed for the Physical Layer of Wireless Standards

    NARCIS (Netherlands)

    Schiphorst, Roelof; Hoeksema, F.W.; Slump, Cornelis H.

    2005-01-01

    We present our contribution to the general-purpose-processor-(GPP)-based radio. We describe a baseband software-defined radio testbed for the physical layer of wireless LAN standards. All physical layer functions have been successfully mapped on a Pentium 4 processor that performs these functions in

  14. Open system LANs and their global interconnection electronics and communications reference series

    CERN Document Server

    Houldsworth, Jack; Caves, Keith; Mazda, FF

    2014-01-01

    Open System LANs and Their Global Interconnection focuses on the OSI layer 1 to 4 standards (the OSI bearer service) and also introduces TCP/IP and some of the proprietary PC Local Area Network (LAN) standards.The publication first provides an introduction to Local Area Networks (LANs) and Wide Area Networks (WANs), Open Systems Interconnection (OSI), and LAN standards. Discussions focus on MAC bridging, token bus, slotted ring, MAC constraints and design considerations, OSI functional standards, OSI model, value of the transport model, benefits and origins of OSI, and significance of the tran

  15. A Novel Ancient Coin-Like Fractal Multiband Antenna for Wireless Applications

    Directory of Open Access Journals (Sweden)

    Zhen Yu

    2017-01-01

    Full Text Available This study proposes a novel square-circle structure fractal multibroadband planar antenna, similar to an ancient Chinese coin-like structure, for second generation (2G, third generation (3G, fourth generation (4G, WLAN, and navigation wireless applications. The device is based on the principles and structural features of conventional monopole antenna elements, combined with the advantages of microstrip antennas and fractal geometry. A fractal method was presented for circular nested square slotted structures, similar to an ancient Chinese copper coin. The proposed antenna adapted five iterations on a fractal structure radiator, which covers more than ten mobile applications in three broad frequency bands with a bandwidth of 70% (1.43–2.97 GHz for DCS1800, TD-SCDMA, WCDMA, CDMA2000, LTE33-41, Bluetooth, GPS (Global Positioning System, BDS (BeiDou Navigation Satellite System, GLONSS (Global Navigation Satellite System, GALILEO (Galileo Satellite Navigation System, and WLAN frequency bands, 16.32% (3.32–3.91 GHz for LTE42, LTE43, and WiMAX frequency bands, and 10.92% (4.85–5.41 GHz for WLAN frequency band. The proposed antenna was fabricated on a 1.6 mm thick G10/FR4 substrate with a dielectric constant of 4.4 and a size of 88.5 × 60 mm2. The measurement results reveal that the omnidirectional radiation patterns achieve a gain of 1.16–3.75 dBi and an efficiency of 40–72%. The good agreement between the measurement results and simulation validates the proposed design approach and satisfies the requirements for various wireless applications.

  16. Subjective Evaluation of Packet Service Performance in UMTS and Heterogeneous Networks

    DEFF Research Database (Denmark)

    Teyeb, Oumer Mohammed; Sørensen, Troels Bundgaard; Mogensen, Preben

    2006-01-01

    . In this paper, such an approach is taken where subjective performance evaluation is undertaken for web browsing and video streaming services in Universal Mobile Telecommunication System (UMTS) and a heterogeneous network comprised of UMTS and Wireless LAN (WLAN). Using a real-time network emulation testbed...

  17. A Pervasive Promotion Model for Personalized Promotion Systems on Using WLAN Localization and NFC Techniques

    Directory of Open Access Journals (Sweden)

    Kam-Yiu Lam

    2015-01-01

    Full Text Available In this paper, we propose a novel pervasive business model for sales promotion in retail chain stores utilizing WLAN localization and near field communication (NFC technologies. The objectives of the model are to increase the customers’ flow of the stores and their incentives in purchasing. In the proposed model, the NFC technology is used as the first mean to motivate customers to come to the stores. Then, with the use of WLAN, the movements of the customers, who are carrying smartphones, within the stores are captured and maintained in the movement database. By interpreting the movements of customers as indicators of their interests to the displayed items, personalized promotion strategies can be formulated to increase their incentives for purchasing future items. Various issues in the application of the adopted localization scheme for locating customers in a store are discussed. To facilitate the item management and space utilization in displaying the items, we propose an enhanced R-tree for indexing the data items maintained in the movement database. Experimental results have demonstrated the effectiveness of the adopted localization scheme in supporting the proposed model.

  18. A Reinforcement Sensor Embedded Vertical Handoff Controller for Vehicular Heterogeneous Wireless Networks

    Directory of Open Access Journals (Sweden)

    Lin Ma

    2013-11-01

    Full Text Available Vehicular communication platforms that provide real-time access to wireless networks have drawn more and more attention in recent years. IEEE 802.11p is the main radio access technology that supports communication for high mobility terminals, however, due to its limited coverage, IEEE 802.11p is usually deployed by coupling with cellular networks to achieve seamless mobility. In a heterogeneous cellular/802.11p network, vehicular communication is characterized by its short time span in association with a wireless local area network (WLAN. Moreover, for the media access control (MAC scheme used for WLAN, the network throughput dramatically decreases with increasing user quantity. In response to these compelling problems, we propose a reinforcement sensor (RFS embedded vertical handoff control strategy to support mobility management. The RFS has online learning capability and can provide optimal handoff decisions in an adaptive fashion without prior knowledge. The algorithm integrates considerations including vehicular mobility, traffic load, handoff latency, and network status. Simulation results verify that the proposed algorithm can adaptively adjust the handoff strategy, allowing users to stay connected to the best network. Furthermore, the algorithm can ensure that RSUs are adequate, thereby guaranteeing a high quality user experience.

  19. Exposure caused by wireless technologies used for short-range indoor communication in homes and offices

    International Nuclear Information System (INIS)

    Schmid, G.; Lager, D.; Preiner, P.; Ueberbacher, R.; Cecil, S.

    2007-01-01

    In order to estimate typical radio frequency exposures from indoor used wireless communication technologies applied in homes and offices, WLAN, Bluetooth and Digital Enhanced Cordless Telecommunications systems, as well as baby surveillance devices and wireless headphones for indoor usage, have been investigated by measurements and numerical computations. Based on optimised measurement methods, field distributions and resulting exposure were assessed on selected products and real exposure scenarios. Additionally, generic scenarios have been investigated on the basis of numerical computations. The obtained results demonstrate that under usual conditions the resulting spatially (over body dimensions) averaged and 6-min time-averaged exposure for persons in the radio frequency fields of the considered applications is below ∼0.1% of the reference level for power density according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines published in 1998. Spatial and temporal peak values can be considerably higher by 2-3 orders of magnitude. In case of some transmitting devices operated in close proximity to the body (e.g. WLAN transmitters), local exposure can reach the same order of magnitude as the basic restriction; however, none of the devices considered in this study exceeded the limits according to the ICNIRP guidelines. (authors)

  20. The Ecological Implications of Light at Night (LAN)

    Science.gov (United States)

    Henshaw, Colin

    2015-08-01

    Summary: Light at night (LAN) is now an established environmental problem, not only for astronomers but for the population at large. It has serious ecological effects that are wide ranging, and its environmental effects may be more serious than ever imagined. The ecological and environmental consequences are examined and emphasis is stressed on resolving the problem before it is too late.Introduction: A casual glance at NASA images of the Earth at night1 reveals the lights of thousands of cities. The larger cities will contain millions of street lights, along with commercial, sports and decorative lighting. Most of these lights are on all night, every night, three hundred and sixty-five nights a year, (fig 1), so they must be having a measurable ecological and environmental effect. The most obvious effect of all this excessive lighting is the light pollution suffered by astronomers.

  1. Interview with Datin Goh Suet Lan on Business Coaching

    Directory of Open Access Journals (Sweden)

    Vahid Nimehchisalem

    2016-10-01

    Full Text Available I had the pleasure of meeting Datin Goh Suet Lan and one of the key members of her team, Mr Murali, in the Faculty of Modern Languages and Communication, Universiti Putra Malaysia with three of my colleagues, Associate Professor Dr Shamala Paramasivam (who initiated this meeting, Dr. Ilyana Binti Jalaluddin, and Dr. Ramiza Binti Darmi. At the end of this meeting, Datin graciously accepted the invitation for an E-mail interview, which is the result of what you are going to read here. The interview will show how it is possible to educate women who are the bread-winners of poverty-stricken families to work more wisely for a better living. In this interview, Datin, who is the president of an NGO called Women of Will (www.womenofwill.org.my, shares the insightful experiences she and her team have reaped in their journey of making a meaningful difference in their community.

  2. Design and Investigation of Photonic Remote Antenna Units for Bidirectional Transmission in the Last Mile Wireless over Fiber System

    Directory of Open Access Journals (Sweden)

    A. Łysiuk

    2013-12-01

    Full Text Available In the article three different photonic Remote Antenna Units (RAU in the last mile Wireless over Fiber links are presented. For construction of RAU commercially available optoelectronic devices were used. The solutions differ from each other by the method of ensuring isolation between transmitting and receiving modes of operation. All RAUs were designed, realized and measured in various scenarios. The results prove that all propositions can be successfully applied to uplink and downlink IEEE 802.11b/g wireless LAN systems, employing Wireless over Fiber technique.

  3. Hemolytic disease of the fetus and newborn caused by anti-Lan.

    Science.gov (United States)

    Brooks, Sarah; Squires, Jerry E

    2014-05-01

    Antibodies to the high-incidence red blood cell (RBC) antigen Lan (Langereis) are typically immunoglobulin G and have been shown to fix complement and cause hemolysis of Lan antigen-positive RBCs. Only three cases of hemolytic disease of the fetus and newborn (HDFN) have been reported involving anti-Lan and all have been characterized as "mild." A 26-year-old Hispanic female presented in her fifth pregnancy for routine obstetric care. Due to progressively rising anti-Lan titers, middle cerebral artery (MCA) Dopplers were performed. At 32 weeks of gestation, the antibody titer had reached 128; the MCA Doppler indicated that fetal anemia was severe. An intrauterine transfusion with Lan antigen-negative RBCs was performed and a viable infant was delivered 25 days later. Three cases of HDFN associated with anti-Lan have been previously reported. While these cases have been associated with somewhat variable serologic findings, none have resulted in fetal demise or severe symptomatology requiring pre- or postnatal intervention other than routine phototherapy. The current report, however, suggests that in some instances anti-Lan can result in a more severe form of HDFN requiring more aggressive prenatal therapy. In spite of previous case reports suggesting that anti-Lan is associated with relatively mild HDFN, this case suggests that in some instances, this antibody can cause severe HDFN requiring prenatal intervention. © 2013 American Association of Blood Banks.

  4. Experimental demonstration of an improved EPON architecture using OFDMA for bandwidth scalable LAN emulation

    DEFF Research Database (Denmark)

    Deng, Lei; Zhao, Ying; Yu, Xianbin

    2011-01-01

    , there is no need to change the existing EPON architecture. Only one receiver at each optical network unit (ONU) is required to detect both LAN traffic and EPON downstream traffic, which makes the proposed system simple and cost-effective. Moreover, flexible assignment of LAN traffic bandwidth is realized...

  5. OIT Wireless Telemetry for Industrial Applications

    Energy Technology Data Exchange (ETDEWEB)

    Manges, WW

    2002-09-03

    ability of wireless sensor networks to operate cooperatively in an environment that includes wireless LANs, wireless headsets, RF heating, wireless crane controls and many other users of the electromagnetic spectrum will probably be the most important issue we can address. A network of units (Figure 1) has been developed that demonstrates the feasibility of direct-sequence spread spectrum wireless sensor networking for industrial environments. The hardware consists of a group of reprogrammable transceivers that can act as sensor nodes or network nodes or both. These units and the team that built them are the heart of a test bed development system that has been used successfully in demonstrations at various industrial sites. As previously reported, these units have been successfully tested at a paper mill. More recently, these units were utilized in a permanent installation at a steel mill. Both of these applications demonstrated the ease with which a new network could be installed, and the reality that DSSS units can operate successfully in plants where narrow band transmitters had previously caused interference with plant operations.

  6. Wireless Biological Electronic Sensors.

    Science.gov (United States)

    Cui, Yue

    2017-10-09

    The development of wireless biological electronic sensors could open up significant advances for both fundamental studies and practical applications in a variety of areas, including medical diagnosis, environmental monitoring, and defense applications. One of the major challenges in the development of wireless bioelectronic sensors is the successful integration of biosensing units and wireless signal transducers. In recent years, there are a few types of wireless communication systems that have been integrated with biosensing systems to construct wireless bioelectronic sensors. To successfully construct wireless biological electronic sensors, there are several interesting questions: What types of biosensing transducers can be used in wireless bioelectronic sensors? What types of wireless systems can be integrated with biosensing transducers to construct wireless bioelectronic sensors? How are the electrical sensing signals generated and transmitted? This review will highlight the early attempts to address these questions in the development of wireless biological electronic sensors.

  7. Dual Band Parasitic Element Patch Antenna for LTE/WLAN Applications

    Directory of Open Access Journals (Sweden)

    BAG Biplab

    2017-05-01

    Full Text Available In this paper, a single layer coaxial fed dual band slotted microstrip antenna is proposed. The proposed antenna consists of two direct couple parasitic elements and L-shape slots on the main resonating element. Two resonant modes are excited and it covers 4G LTE and WLAN middle band. The -10dB impedance bandwidth for resonant frequency of 2.35GHz and 5.28GHz are 140MHz (2.25-2.39GHz and 570MHz (5.18-5.75GHz, respectively. The measured VSWR at 2.35GHz is 1.27 and at 5.28GHz is 1.41. The proposed antenna is simple in design and compact in size. The simulated and measured results are in good agreement.

  8. Dual-Band Compact Planar Antenna for a Low-Cost WLAN USB Dongle

    Directory of Open Access Journals (Sweden)

    Maurício Henrique Costa Dias

    2014-01-01

    Full Text Available Among the present technologies for WLAN devices, USB dongles still play a noticeable role. One major design challenge regards the antenna, which unavoidably has to comply with a very small volume available and sometimes should also allow multiband operation. In this scope, the present work discusses a dual-band WiFi compact planar IFA-based antenna design for a low-cost USB dongle application. Like most of the related published solutions, the methodology for deriving the present proposition was assisted by the use of an antenna analysis software. A prototype was assembled and tested in order to qualify the radiator design. Practical operation conditions were considered in the tests, such as the influence of the dongle case and the effect of the notebook itself. The results complied with the design constraints, presenting an impedance match quite stable regardless of the stick position alongside a laptop base.

  9. Analysis of an Adaptive P-Persistent MAC Scheme for WLAN Providing Delay Fairness

    Science.gov (United States)

    Yen, Chih-Ming; Chang, Chung-Ju; Chen, Yih-Shen; Huang, Ching Yao

    The paper proposes and analyzes an adaptive p-persistent-based (APP) medium access control (MAC) scheme for IEEE 802.11 WLAN. The APP MAC scheme intends to support delay fairness for every station in each access, denoting small delay variance. It differentiates permission probabilities of transmission for stations which are incurred with various packet delays. This permission probability is designed as a function of the numbers of retransmissions and re-backoffs so that stations with larger packet delay are endowed with higher permission probability. Also, the scheme is analyzed by a Markov-chain analysis, where the collision probability, the system throughput, and the average delay are successfully obtained. Numerical results show that the proposed APP MAC scheme can attain lower mean delay and higher mean throughput. In the mean time, simulation results are given to justify the validity of the analysis, and also show that the APP MAC scheme can achieve more delay fairness than conventional algorithms.

  10. A Novel Metamaterial MIMO Antenna with High Isolation for WLAN Applications

    Directory of Open Access Journals (Sweden)

    Nguyen Khac Kiem

    2015-01-01

    Full Text Available A compact 2×2 metamaterial-MIMO antenna for WLAN applications is presented in this paper. The MIMO antenna is designed by placing side by side two single metamaterial antennas which are constructed based on the modified composite right/left-handed (CRLH model. By adding another left-handed inductor, the total left-handed inductor of the modified CRLH model is increased remarkably in comparison with that of conventional CRLH model. As a result, the proposed metamaterial antenna achieves 60% size reduction in comparison with the unloaded antenna. The MIMO antenna is electrically small (30 mm × 44 mm with an edge-to-edge separation between two antennas of 0.06λ0 at 2.4 GHz. In order to reduce the mutual coupling of the antenna, a defected ground structure (DGS is inserted to suppress the effect of surface current between elements of the proposed antenna. The final design of the MIMO antenna satisfies the return loss requirement of less than −10 dB in a bandwidth ranging from 2.38 GHz to 2.5 GHz, which entirely covers WLAN frequency band allocated from 2.4 GHz to 2.48 GHz. The antenna also shows a high isolation coefficient which is less than −35 dB over the operating frequency band. A good agreement between simulation and measurement is shown in this context.

  11. Paper-based inkjet-printed tri-band U-slot monopole antenna for wireless applications

    KAUST Repository

    Abutarboush, Hattan

    2012-01-01

    Realization of a U-slot tri-band monopole antenna on a low-cost paper substrate using inkjet-printed technology is presented for the first time. The U-shaped slot is optimized to enhance the bandwidth and to achieve tri-band operation of 1.57, 3.2, and 5 GHz with measured impedance bandwidths of 3.21%, 28.1%, and 36%, respectively. The antenna is fabricated through a metallic nanoparticle ink on a standard commercial paper. Thus, the antenna can be used to cover the GPS, WiMAX, HiperLAN/2, and WLAN. The antenna has a compact size of 12 × 37.3 × 0.44 mm3 , leaving enough space for the driving electronics on the paper substrate. The impedance bandwidth, current distributions, radiation patterns, gain, and efficiency of the antenna have been studied through computer simulations and measurements. © 2002-2011 IEEE.

  12. Flip-chip integrated optical wireless transceivers

    Science.gov (United States)

    O'Brien, Dominic C.; Faulkner, Grahame E.; Zyambo, Emmanuel B.; Edwards, David J.; Stavrinou, Paul N.; Parry, Gareth; Bellon, Jacques; Sibley, Martin J. N.; Lalithambika, Vinod A.; Joyner, Valencia M.; Samsudin, Rina J.; Holburn, David M.; Mears, Robert J.

    2002-12-01

    The widespread use of Optical LANs is dependent on the ability to fabricate low cost transceiver components. These are usually complex, and fabrication involves the integration of optoelectronic and electronic devices, as well as optical components. A consortium of four UK universities are currently involved in a project to demonstrate integrated optical wireless transceiver subsystems that can provide eye-safe line of sight in-building communication at 155Mbit/s and above. In this paper we discuss the flip-chip integration of two-dimensional arrays of novel microcavity LEDs with custom CMOS integrated circuits in order to produce solid state tracking emitters. Design, fabrication and integration of these structures are detailed. The scaleability and future capability available given further optimisation and development of these systems is also discussed.

  13. Empirical investigation on the dependence of TCP downstream throughput on SNR in an IEEE802.11b WLAN system

    Directory of Open Access Journals (Sweden)

    Ikponmwosa Oghogho

    2017-04-01

    Full Text Available The dependence of TCP downstream throughput (TCPdownT on signal to noise ratio (SNR in an IEEE802.11b WLAN system was investigated in various environments and varieties of QoS traffic. TCPdownT was measured for various SNR observed. An Infrastructure based IEEE802.11b WLAN system having networked computers on which measurement software were installed, was set up consecutively in various environments (open corridor, small offices with block walls and plaster boards and free space. Empirical models describing TCPdownT against SNR for different signal ranges (all ranges of signals, strong signals only, grey signals only and weak signals only were statistically generated and validated. As the SNR values changed from high (strong signals through low (grey signals to very low (weak signals, our results show a strong dependence of TCPdownT on the received SNR. Our models showed lower RMS errors when compared with other similar models. We observed RMS errors of 0.6734791 Mbps, 0.472209 Mbps, 0.9111563 Mbps and 0.5764460 Mbps for general (all SNR model, strong signals model, grey signals model and Weak signals model respectively. Our models will provide researchers and WLAN systems users with a tool to estimate the TCP downstream throughput in a real network in various environments by monitoring the received SNR.

  14. A Wireless Sensor Enabled by Wireless Power

    Science.gov (United States)

    Lee, Da-Sheng; Liu, Yu-Hong; Lin, Chii-Ruey

    2012-01-01

    Through harvesting energy by wireless charging and delivering data by wireless communication, this study proposes the concept of a wireless sensor enabled by wireless power (WPWS) and reports the fabrication of a prototype for functional tests. One WPWS node consists of wireless power module and sensor module with different chip-type sensors. Its main feature is the dual antenna structure. Following RFID system architecture, a power harvesting antenna was designed to gather power from a standard reader working in the 915 MHz band. Referring to the Modbus protocol, the other wireless communication antenna was integrated on a node to send sensor data in parallel. The dual antenna structure integrates both the advantages of an RFID system and a wireless sensor. Using a standard UHF RFID reader, WPWS can be enabled in a distributed area with a diameter up to 4 m. Working status is similar to that of a passive tag, except that a tag can only be queried statically, while the WPWS can send dynamic data from the sensors. The function is the same as a wireless sensor node. Different WPWSs equipped with temperature and humidity, optical and airflow velocity sensors are tested in this study. All sensors can send back detection data within 8 s. The accuracy is within 8% deviation compared with laboratory equipment. A wireless sensor network enabled by wireless power should be a totally wireless sensor network using WPWS. However, distributed WPWSs only can form a star topology, the simplest topology for constructing a sensor network. Because of shielding effects, it is difficult to apply other complex topologies. Despite this limitation, WPWS still can be used to extend sensor network applications in hazardous environments. Further research is needed to improve WPWS to realize a totally wireless sensor network. PMID:23443370

  15. A Wireless Sensor Enabled by Wireless Power

    Directory of Open Access Journals (Sweden)

    Da-Sheng Lee

    2012-11-01

    Full Text Available Through harvesting energy by wireless charging and delivering data by wireless communication, this study proposes the concept of a wireless sensor enabled by wireless power (WPWS and reports the fabrication of a prototype for functional tests. One WPWS node consists of wireless power module and sensor module with different chip-type sensors. Its main feature is the dual antenna structure. Following RFID system architecture, a power harvesting antenna was designed to gather power from a standard reader working in the 915 MHz band. Referring to the Modbus protocol, the other wireless communication antenna was integrated on a node to send sensor data in parallel. The dual antenna structure integrates both the advantages of an RFID system and a wireless sensor. Using a standard UHF RFID reader, WPWS can be enabled in a distributed area with a diameter up to 4 m. Working status is similar to that of a passive tag, except that a tag can only be queried statically, while the WPWS can send dynamic data from the sensors. The function is the same as a wireless sensor node. Different WPWSs equipped with temperature and humidity, optical and airflow velocity sensors are tested in this study. All sensors can send back detection data within 8 s. The accuracy is within 8% deviation compared with laboratory equipment. A wireless sensor network enabled by wireless power should be a totally wireless sensor network using WPWS. However, distributed WPWSs only can form a star topology, the simplest topology for constructing a sensor network. Because of shielding effects, it is difficult to apply other complex topologies. Despite this limitation, WPWS still can be used to extend sensor network applications in hazardous environments. Further research is needed to improve WPWS to realize a totally wireless sensor network.

  16. A wireless sensor enabled by wireless power.

    Science.gov (United States)

    Lee, Da-Sheng; Liu, Yu-Hong; Lin, Chii-Ruey

    2012-11-22

    Through harvesting energy by wireless charging and delivering data by wireless communication, this study proposes the concept of a wireless sensor enabled by wireless power (WPWS) and reports the fabrication of a prototype for functional tests. One WPWS node consists of wireless power module and sensor module with different chip-type sensors. Its main feature is the dual antenna structure. Following RFID system architecture, a power harvesting antenna was designed to gather power from a standard reader working in the 915 MHz band. Referring to the Modbus protocol, the other wireless communication antenna was integrated on a node to send sensor data in parallel. The dual antenna structure integrates both the advantages of an RFID system and a wireless sensor. Using a standard UHF RFID reader, WPWS can be enabled in a distributed area with a diameter up to 4 m. Working status is similar to that of a passive tag, except that a tag can only be queried statically, while the WPWS can send dynamic data from the sensors. The function is the same as a wireless sensor node. Different WPWSs equipped with temperature and humidity, optical and airflow velocity sensors are tested in this study. All sensors can send back detection data within 8 s. The accuracy is within 8% deviation compared with laboratory equipment. A wireless sensor network enabled by wireless power should be a totally wireless sensor network using WPWS. However, distributed WPWSs only can form a star topology, the simplest topology for constructing a sensor network. Because of shielding effects, it is difficult to apply other complex topologies. Despite this limitation, WPWS still can be used to extend sensor network applications in hazardous environments. Further research is needed to improve WPWS to realize a totally wireless sensor network.

  17. Wireless data transfer with mm-waves for future tracking detectors

    International Nuclear Information System (INIS)

    Pelikan, D.; Bingefors, N.; Brenner, R.; Gustafsson, L.; Dancila, D.

    2014-01-01

    Wireless data transfer has revolutionized the consumer market for the last decade generating many products equipped with transmitters and receivers for wireless data transfer. Wireless technology opens attractive possibilities for data transfer in future tracking detectors. The reduction of wires and connectors for data links is certainly beneficial both for the material budget and the reliability of the system. An advantage of wireless data transfer is the freedom of routing signals which today is particularly complicated when bringing the data the first 50 cm out of the tracker. With wireless links intelligence can be built into a tracker by introducing communication between tracking layers within a region of interest which would allow the construction of track primitives in real time. The wireless technology used in consumer products is however not suitable for tracker readouts. The low data transfer capacity of current 5 GHz transceivers and the relatively large feature sizes of the components is a disadvantage.Due to the requirement of high data rates in tracking detectors high bandwidth is required. The frequency band around 60 GHz turns out to be a very promising candidate for data transfer in a detector system. The high baseband frequency allows for data transfer in the order of several Gbit/s. Due to the small wavelength in the mm range only small structures are needed for the transmitting and receiving electronics. The 60 GHz frequency band is a strong candidate for future WLAN applications hence components are already starting to be available on the market.Patch antennas produced on flexible Printed Circuit Board substrate that can be used for wireless communication in future trackers are presented in this article. The antennas can be connected to transceivers for data transmission/reception or be connected by wave-guides to structures capable of bringing the 60 GHz signal behind boundaries. Results on simulation and fabrication of these antennas are

  18. Když v Lanžhotě túkli...

    Czech Academy of Sciences Publication Activity Database

    Altman, Karel

    2015-01-01

    Roč. 51, č. 4 (2015), s. 15 ISSN 0323-1542 Institutional support: RVO:68378076 Keywords : fight * neighbor relations * conflict * court * city Lanžhot Subject RIV: AC - Archeology, Anthropology, Ethnology

  19. An Intelligent Handover Management System for Future Generation Wireless Networks

    Directory of Open Access Journals (Sweden)

    Kassar Meriem

    2008-01-01

    Full Text Available Abstract Future generation wireless networks should provide to mobile users the best connectivity to services anywhere at anytime. The most challenging problem is the seamless intersystem/vertical mobility across heterogeneous wireless networks. In order to answer it, a vertical handover management system is needed. In our paper, we propose an intelligent solution answering user requirements and ensuring service continuity. We focus on a vertical handover decision strategy based on the context-awareness concept. The given strategy chooses the appropriate time and the most suitable access network among those available to perform a handover. It uses advanced decision algorithms (for more efficiency and intelligence and it is governed by handover policies as decision rules (for more flexibility and optimization. To maintain a seamless service continuity, handover execution is based on mobile IP functionalities. We study our decision system in a case of a 3G/UMTS-WLAN scenario and we discuss all the handover decision issues in our solution.

  20. Secure and Efficient Data Transmission over Body Sensor and Wireless Networks

    Directory of Open Access Journals (Sweden)

    Madhur Sikri

    2008-09-01

    Full Text Available This paper addresses the transmission of medical and context-aware data from mobile patients to healthcare centers over heterogeneous wireless networks. A handheld device, called personal wireless hub (PWH, of each mobile patient first gathers and aggregates the vital sign and context-aware data for various telemedicine applications. PWH transmits the aggregated data to the remote healthcare center over multiple wireless interfaces such as cellular, WLAN, and WiMAX. The aggregated data contain both periodic data and those nonperiodic unpredictable emergency messages that are sporadic and delayintolerant. This paper addresses the problem of providing QoS (e.g., minimum delay, sufficient data rate, acceptable blocking, and/or dropping rate by designing a packet scheduling and channel/network allocation algorithm over wireless networks. The proposed resource-efficient QoS mechanism is simple and collaborates with an adaptive security algorithm. The QoS and security are achieved mainly with the collaboration of differentiator, delay monitor, data classifier, and scheduler modules within the PWH. This paper also discusses secure data transmission over body sensor networks by introducing key establishment and management algorithms. Simulation results show that the proposed framework achieves low-blocking probability, meets delay requirements, and provides energy-efficient secure communication for the combination of vital signs and context-aware data.

  1. Secure and Efficient Data Transmission over Body Sensor and Wireless Networks

    Directory of Open Access Journals (Sweden)

    Challa Narasimha

    2008-01-01

    Full Text Available Abstract This paper addresses the transmission of medical and context-aware data from mobile patients to healthcare centers over heterogeneous wireless networks. A handheld device, called personal wireless hub (PWH, of each mobile patient first gathers and aggregates the vital sign and context-aware data for various telemedicine applications. PWH transmits the aggregated data to the remote healthcare center over multiple wireless interfaces such as cellular, WLAN, and WiMAX. The aggregated data contain both periodic data and those nonperiodic unpredictable emergency messages that are sporadic and delayintolerant. This paper addresses the problem of providing QoS (e.g., minimum delay, sufficient data rate, acceptable blocking, and/or dropping rate by designing a packet scheduling and channel/network allocation algorithm over wireless networks. The proposed resource-efficient QoS mechanism is simple and collaborates with an adaptive security algorithm. The QoS and security are achieved mainly with the collaboration of differentiator, delay monitor, data classifier, and scheduler modules within the PWH. This paper also discusses secure data transmission over body sensor networks by introducing key establishment and management algorithms. Simulation results show that the proposed framework achieves low-blocking probability, meets delay requirements, and provides energy-efficient secure communication for the combination of vital signs and context-aware data.

  2. Adaptive Wireless Transceiver Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Many wireless technologies are already available for sensor applications. It is inevitable that many non-interoperable wireless technologies between 400 MHz and 5.8...

  3. An Adaptive Handover Prediction Scheme for Seamless Mobility Based Wireless Networks

    Directory of Open Access Journals (Sweden)

    Ali Safa Sadiq

    2014-01-01

    Full Text Available We propose an adaptive handover prediction (AHP scheme for seamless mobility based wireless networks. That is, the AHP scheme incorporates fuzzy logic with AP prediction process in order to lend cognitive capability to handover decision making. Selection metrics, including received signal strength, mobile node relative direction towards the access points in the vicinity, and access point load, are collected and considered inputs of the fuzzy decision making system in order to select the best preferable AP around WLANs. The obtained handover decision which is based on the calculated quality cost using fuzzy inference system is also based on adaptable coefficients instead of fixed coefficients. In other words, the mean and the standard deviation of the normalized network prediction metrics of fuzzy inference system, which are collected from available WLANs are obtained adaptively. Accordingly, they are applied as statistical information to adjust or adapt the coefficients of membership functions. In addition, we propose an adjustable weight vector concept for input metrics in order to cope with the continuous, unpredictable variation in their membership degrees. Furthermore, handover decisions are performed in each MN independently after knowing RSS, direction toward APs, and AP load. Finally, performance evaluation of the proposed scheme shows its superiority compared with representatives of the prediction approaches.

  4. Radiofrequency Field Distribution Assessment in Indoor Areas Covered by Wireless Local Area Network

    Directory of Open Access Journals (Sweden)

    HELBET, R.

    2009-02-01

    Full Text Available Electromagnetic environment becomes day by day more congested. Radio communication systems in the short range are now part of everyday life, and there is a need to also assess the pollution level due to their emission if we take into account human health and protection. There is consistent scientific evidence that environmental electromagnetic field may cause undesirable biological effects or even health hazards. Present paper aims at giving a view on exposure level due to wireless local area networks (WLAN emission solely, as part of environmental radiofrequency pollution. Highly accurate measurements were made indoor by using a frequency-selective measurement system and identifying the correct settings for an error-minimum assessment. We focused on analysis of the electric flux density distribution inside a room, in the far field of the emitting antennas, in case of a single network communication channel. We analyze the influence the network configuration parameters have on the field level. Distance from the source and traffic rate are also important parameters that affect the exposure level. Our measurements indicate that in the immediate vicinity of the WLAN stations the average field may reach as much as 13% from the present accepted reference levels given in the human exposure standards.

  5. Achievable Throughput-Based MAC Layer Handoff in IEEE 802.11 Wireless Local Area Networks

    Directory of Open Access Journals (Sweden)

    Wu Haitao

    2009-01-01

    Full Text Available We propose a MAC layer handoff mechanism for IEEE 802.11 Wireless Local Area Networks (WLAN to give benefit to bandwidth-greedy applications at STAs. The proposed mechanism determines an optimal AP with the maximum achievable throughput rather than the best signal condition by estimating the AP's bandwidth with a new on-the-fly measurement method, Transient Frame Capture (TFC, and predicting the actual throughput could be achieved at STAs. Since the TFC is employed based on the promiscuous mode of WLAN NIC, STAs can avoid the service degradation through the current associated AP. In addition, the proposed mechanism is a client-only solution which does not require any modification of network protocol on APs. To evaluate the performance of the proposed mechanism, we develop an analytic model to estimate reliable and accurate bandwidth of the AP and demonstrate through testbed measurement with various experimental study methods. We also validate the fairness of the proposed mechanism through simulation studies.

  6. Adaptive Backoff Algorithm for Contention Window for Dense IEEE 802.11 WLANs

    Directory of Open Access Journals (Sweden)

    Ikram Syed

    2016-01-01

    Full Text Available The performance improvement in IEEE 802.11 WLANs in widely fluctuating network loads is a challenging task. To improve the performance in this saturated state, we develop an adaptive backoff algorithm that maximizes the system throughput, reduces the collision probability, and maintains a high fairness for the IEEE 802.11 DCF under dense network conditions. In this paper, we present two main advantages of the proposed ABA-CW algorithm. First, it estimates the number of active stations and then calculates an optimal contention window based on the active station number. Each station calculates the channel state probabilities by observing the channel for the total backoff period. Based on these channel states probabilities, each station can estimate the number of active stations in the network, after which it calculates the optimal CW utilizing the estimated active number of stations. To evaluate the proposed mechanism, we derive an analytical model to determine the network performance. From our results, the proposed ABA-CW mechanism achieved better system performance compared to fixed-CW (BEB, EIED, LILD, and SETL and adaptive-CW (AMOCW, Idle Sense mechanisms. The simulation results confirmed the outstanding performance of the proposed mechanism in that it led to a lower collision probability, higher throughput, and high fairness.

  7. CCNA Wireless Study Guide

    CERN Document Server

    Lammle, Todd

    2010-01-01

    A complete guide to the CCNA Wireless exam by leading networking authority Todd Lammle. The CCNA Wireless certification is the most respected entry-level certification in this rapidly growing field. Todd Lammle is the undisputed authority on networking, and this book focuses exclusively on the skills covered in this Cisco certification exam. The CCNA Wireless Study Guide joins the popular Sybex study guide family and helps network administrators advance their careers with a highly desirable certification.: The CCNA Wireless certification is the most respected entry-level wireless certification

  8. The List of Available Names (LAN): A new generation for stable taxonomic names in zoology?

    Science.gov (United States)

    Alonso-Zarazaga, Miguel A; Fautin, Daphne Gail; Michel, Ellinor

    2016-01-01

    The List of Available Names in Zoology (LAN) is an inventory of names with specific scope in time and content, presented and approved in parts, and constituted as a cumulative index of names available for use in zoological nomenclature. It was defined in Article 79 in the fourth edition of the International Code of Zoological Nomenclature. The LAN is likely to gain importance with the development of the online Official Registry for Zoological Nomenclature (ZooBank) as it is potentially a source of many nomenclaturally certified names. Article 79 describes the deliberative process for adding large numbers of names to the LAN simultaneously, detailing steps and chronology for submission of a candidate Part to the LAN and consideration of a candidate Part by the public and Commission, but it is largely mute about the contents of a candidate Part. It does make clear that a name within the scope of a Part but not on the LAN has no nomenclatural standing, even if it had previously been considered available, thereby preventing long-forgotten names from displacing accepted ones and the accumulation of nomina dubia. Thus, for taxa on the LAN, nomenclatural archaeology - the resurrecting of old unused names to replace by priority names in current usage - will not be worthwhile. Beyond that, it has been unclear if Article 79 is intended to document every available name known within the scope of the Part, or if its intention is to pare the inventory of available names within the scope of the Part. Consideration by the Commission and two committees to deal with the LAN have defined steps to implement Article 79 with the latter intent. Procedures for consideration of a candidate Part are defined in a manual, published as an appendix in this volume.

  9. Efficient MAC Protocol for Subcarrier-Wise Rate Adaptation over WLAN

    Directory of Open Access Journals (Sweden)

    Sung Won Kim

    2010-01-01

    Full Text Available While bit-loading algorithms over wireless systems have been extensively studied, the development of a protocol which implements bit-loading-based rate adaptation over wireless systems has not been highlighted. The design of such a protocol is not a trivial problem, due to the overhead associated with the feedback information. In this paper, a novel protocol is proposed to provide an efficient way to implement subcarrier-wise rate adaptation in OFDM-based wireless systems. When receiving a Ready-To-Send (RTS packet, the receiver determines the number of bits to be allocated on each subcarrier through channel estimation. This decision is delivered to the sender using an additional OFDM symbol in the Clear-To-Send (CTS packet. That is, bit-allocation over subcarriers is achieved using only one additional OFDM symbol. The protocol enhances the channel efficiency in spite of the overhead of one additional OFDM symbol.

  10. A Potential Transmitter Architecture for Future Generation Green Wireless Base Station

    Directory of Open Access Journals (Sweden)

    Mike Faulkner

    2009-01-01

    Full Text Available Current radio frequency power amplifiers in 3G base stations have very high power consumption leading to a hefty cost and negative environmental impact. In this paper, we propose a potential architecture design for future wireless base station. Issues associated with components of the architecture are investigated. The all-digital transmitter architecture uses a combination of envelope elimination and restoration (EER and pulse width modulation (PWM/pulse position modulation (PPM modulation. The performance of this architecture is predicted from the measured output power and efficiency curves of a GaN amplifier. 57% efficiency is obtained for an OFDM signal limited to 8 dB peak to average power ratio. The PWM/PPM drive signal is generated using the improved Cartesian sigma delta techniques. It is shown that an RF oversampling by a factor of four meets the WLAN spectral mask, and WCDMA specification is met by an RF oversampling of sixteen.

  11. Design of Compact Flower Shape Dual Notched-Band Monopole Antenna for Extended UWB Wireless Applications

    Science.gov (United States)

    Sharma, Manish; Awasthi, Y. K.; Singh, Himanshu; Kumar, Raj; Kumari, Sarita

    2016-11-01

    In this letter, a compact monopole antenna for ultra wideband (UWB) applications is proposed with small size of 18×20=360 mm2. Antenna consist of a flower shape radiating patch with a pair of C-shaped slots which offer two notch bands for WiMAX (3.04-3.68 GHz) & WLAN (4.73-5.76 GHz) and two rectangular shaped slots in the ground plane which provides a wide measured usable fractional extended bandwidth of 163 % (2.83-14.0 GHz) with improved VSWR. Moreover, it is also convenient for other wireless application as close range radar, 8-12 GHz in X-band. Measured radiation patterns exhibits nearly omnidirectional in H-plane and dipole like pattern in E-plane across the bandwidth and furthermore exhibits good time domain performance.

  12. A New Markovian Prediction Scheme for Resource Reservations in Wireless Networks with Mobile Hosts

    Directory of Open Access Journals (Sweden)

    Peppino Fazio

    2012-01-01

    Full Text Available Nowadays, mobile service requests in wireless networking are aimed to the benefit of a good level of satisfaction for the received Quality of Service (QoS guarantees. In this paper, a new prediction algorithm is proposed, for the pre-reservation of passive bandwidth, when mobile users moves under radio coverage that can be considered as a cellular one (GSM, UMTS, WLAN clusters, etc.. The Hidden Markov Chains (HMC theory is used to design the predictor, as the main component of the proposed idea, that does not depend on the considered transmission technology, mobility model or vehicular scenario. Mobile ReSerVation Protocol (MRSVP has been used in order to realize the active/passive bandwidth reservation in the considered network topology. Different simulation campaigns have been carried out in order to appreciate the benefits of the proposed idea.

  13. A Potential Transmitter Architecture for Future Generation Green Wireless Base Station

    Directory of Open Access Journals (Sweden)

    Cijvat Ellie

    2009-01-01

    Full Text Available Abstract Current radio frequency power amplifiers in 3G base stations have very high power consumption leading to a hefty cost and negative environmental impact. In this paper, we propose a potential architecture design for future wireless base station. Issues associated with components of the architecture are investigated. The all-digital transmitter architecture uses a combination of envelope elimination and restoration (EER and pulse width modulation (PWM/pulse position modulation (PPM modulation. The performance of this architecture is predicted from the measured output power and efficiency curves of a GaN amplifier. 57% efficiency is obtained for an OFDM signal limited to 8 dB peak to average power ratio. The PWM/PPM drive signal is generated using the improved Cartesian sigma delta techniques. It is shown that an RF oversampling by a factor of four meets the WLAN spectral mask, and WCDMA specification is met by an RF oversampling of sixteen.

  14. Wireless Indoor Location Estimation Based on Neural Network RSS Signature Recognition (LENSR)

    Energy Technology Data Exchange (ETDEWEB)

    Kurt Derr; Milos Manic

    2008-06-01

    Location Based Services (LBS), context aware applications, and people and object tracking depend on the ability to locate mobile devices, also known as localization, in the wireless landscape. Localization enables a diverse set of applications that include, but are not limited to, vehicle guidance in an industrial environment, security monitoring, self-guided tours, personalized communications services, resource tracking, mobile commerce services, guiding emergency workers during fire emergencies, habitat monitoring, environmental surveillance, and receiving alerts. This paper presents a new neural network approach (LENSR) based on a competitive topological Counter Propagation Network (CPN) with k-nearest neighborhood vector mapping, for indoor location estimation based on received signal strength. The advantage of this approach is both speed and accuracy. The tested accuracy of the algorithm was 90.6% within 1 meter and 96.4% within 1.5 meters. Several approaches for location estimation using WLAN technology were reviewed for comparison of results.

  15. Parasitic-Element-Loaded UWB Antenna with Band-Stop Function for Mobile Handset Wireless USB

    Directory of Open Access Journals (Sweden)

    Yohan Lim

    2012-01-01

    Full Text Available A UWB antenna loaded by parasitic elements for wireless USB of mobile handsets is proposed for UWB service in which a band-stop function of 5.725–5.825 GHz WLAN band is required. Two kinds of parasitic elements are incorporated into a rectangular radiator to obtain enhanced impedance bandwidth and band-stop function. The proposed antenna is very compact in size. Wide bandwidths of 3.15–4.75 GHz and 7.2–10.2 GHz are achieved while 5.725–5.825 GHz is notched. Three different shapes of conventional mobile terminals are also considered for measurement.

  16. Optimized tuning of contention window for IEEE 802.11 WLAN ...

    African Journals Online (AJOL)

    In wireless networks, the size of Contention Window (CW) plays a vital role as it changes the throughput and delay of the networks considerably. The proposed Collision Ratio based BackOff (CRBO) algorithm uses collision ratio to suggest CW updation after the successful and unsuccessful transmission events. This leads ...

  17. Quality assessment in lan houses through the adaptation of the servqual instrument

    Directory of Open Access Journals (Sweden)

    Tiago José Menezes Gonçalves

    2012-03-01

    Full Text Available This work was conducted with the objective of developing an adapted questionnaire from the SERVQUAL instrument to measure the quality of services provided by Lan Houses. In addition, the use of analysis Quartiles  was investigated in prioritizing the items to perform corrective actions to improve the quality of service analysis. For achieve this objectives, an adaptation of the SERVQUAL instrument was developed based on the literature and interviews with managers of Lan Houses, from where information was extracted for its adaptation to the object of study. Once developed, the instrument was used and the managerial implications of its use (in conjunction with the Quartiles Analysis were discussed with the Lan House’s manager, from where feedback was obtained for the validity of the model developed.

  18. Wireless physical layer security

    OpenAIRE

    Poor, H. Vincent; Schaefer, Rafael F.

    2016-01-01

    Security is a very important issue in the design and use of wireless networks. Traditional methods of providing security in such networks are impractical for some emerging types of wireless networks due to the light computational abilities of some wireless devices [such as radio-frequency identification (RFID) tags, certain sensors, etc.] or to the very large scale or loose organizational structure of some networks. Physical layer security has the potential to address these concerns by taking...

  19. Scalable Video Streaming Relay for Smart Mobile Devices in Wireless Networks.

    Science.gov (United States)

    Kwon, Dongwoo; Je, Huigwang; Kim, Hyeonwoo; Ju, Hongtaek; An, Donghyeok

    2016-01-01

    Recently, smart mobile devices and wireless communication technologies such as WiFi, third generation (3G), and long-term evolution (LTE) have been rapidly deployed. Many smart mobile device users can access the Internet wirelessly, which has increased mobile traffic. In 2014, more than half of the mobile traffic around the world was devoted to satisfying the increased demand for the video streaming. In this paper, we propose a scalable video streaming relay scheme. Because many collisions degrade the scalability of video streaming, we first separate networks to prevent excessive contention between devices. In addition, the member device controls the video download rate in order to adapt to video playback. If the data are sufficiently buffered, the member device stops the download. If not, it requests additional video data. We implemented apps to evaluate the proposed scheme and conducted experiments with smart mobile devices. The results showed that our scheme improves the scalability of video streaming in a wireless local area network (WLAN).

  20. Scalable Video Streaming Relay for Smart Mobile Devices in Wireless Networks

    Science.gov (United States)

    Kwon, Dongwoo; Je, Huigwang; Kim, Hyeonwoo; Ju, Hongtaek; An, Donghyeok

    2016-01-01

    Recently, smart mobile devices and wireless communication technologies such as WiFi, third generation (3G), and long-term evolution (LTE) have been rapidly deployed. Many smart mobile device users can access the Internet wirelessly, which has increased mobile traffic. In 2014, more than half of the mobile traffic around the world was devoted to satisfying the increased demand for the video streaming. In this paper, we propose a scalable video streaming relay scheme. Because many collisions degrade the scalability of video streaming, we first separate networks to prevent excessive contention between devices. In addition, the member device controls the video download rate in order to adapt to video playback. If the data are sufficiently buffered, the member device stops the download. If not, it requests additional video data. We implemented apps to evaluate the proposed scheme and conducted experiments with smart mobile devices. The results showed that our scheme improves the scalability of video streaming in a wireless local area network (WLAN). PMID:27907113

  1. The Most Possible Scheme of Joint Service Detection for the Next Wireless Communication Technologies

    Directory of Open Access Journals (Sweden)

    Firdaus Firdaus

    2013-03-01

    Full Text Available The era of beyond third generation wireless communication is highly heterogeneous in that it comprises several radio access technologies that need to be joined into a single multimode terminal. In this respect, this paper introduces a common service recognition system for the next wireless communication technologies i.e. Long Term Evolution (LTE, WiMAX or IEEE 802.16, and Wireless Local Area Network (WLAN or IEEE 802.11. It is done in physical layer as one of multimode terminal ability regardless network cooperation existence. We investigated on the preamble and synchronization signals as indicators of the available services instead of carrier frequency detection. To detect these signals, we proposed a time domain detection system consisting of auto-correlation, cross-correlation, and a peak period detection. Based on complexity analysis, this paper proposes the most possible scheme with lower complexity than cross-correlation implementation. Moreover, the fixed point simulation results show that the proposed system satisfies the minimum receiver sensitivity requirements that specified in the standards.

  2. Wireless security in mobile health.

    Science.gov (United States)

    Osunmuyiwa, Olufolabi; Ulusoy, Ali Hakan

    2012-12-01

    Mobile health (m-health) is an extremely broad term that embraces mobile communication in the health sector and data packaging. The four broad categories of wireless networks are wireless personal area network, wireless metropolitan area network, wireless wide area network, and wireless local area network. Wireless local area network is the most notable of the wireless networking tools obtainable in the health sector. Transfer of delicate and critical information on radio frequencies should be secure, and the right to use must be meticulous. This article covers the business opportunities in m-health, threats faced by wireless networks in hospitals, and methods of mitigating these threats.

  3. Wireless Emulation Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Wireless Emulation Laboratory (WEL) is a researchtest bed used to investigate fundamental issues in networkscience. It is a research infrastructure that emulates...

  4. Adaptive Wireless Transceiver Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Wireless technologies are an increasingly attractive means for spatial data, input, manipulation, and distribution. Mobitrum is proposing an innovative Adaptive...

  5. Cross-Layer Measurement on an IEEE 802.11g Wireless Network Supporting MPEG-2 Video Streaming Applications in the Presence of Interference

    Directory of Open Access Journals (Sweden)

    Alessandro Sona

    2010-01-01

    Full Text Available The performance of wireless local area networks supporting video streaming applications, based on MPEG-2 video codec, in the presence of interference is here dealt with. IEEE 802.11g standard wireless networks, that do not support QoS in according with IEEE 802.11e standard, are, in particular, accounted for and Bluetooth signals, additive white Gaussian noise, and competitive data traffic are considered as sources of interference. The goal is twofold: from one side, experimentally assessing and correlating the values that some performance metrics assume at the same time at different layers of an IEEE 802.11g WLAN delivering video streaming in the presence of in-channel interference; from the other side, deducing helpful and practical hints for designers and technicians, in order to efficiently assess and enhance the performance of an IEEE 802.11g WLAN supporting video streaming in some suitable setup conditions and in the presence of interference. To this purpose, an experimental analysis is planned following a cross-layer measurement approach, and a proper testbed within a semianechoic chamber is used. Valuable results are obtained in terms of signal-to-interference ratio, packet loss ratio, jitter, video quality, and interference data rate; helpful hints for designers and technicians are finally gained.

  6. An Analysis of Impact Factors for Positioning Performance in WLAN Fingerprinting Systems Using Ishikawa Diagrams and a Simulation Platform

    Directory of Open Access Journals (Sweden)

    Keqiang Liu

    2017-01-01

    Full Text Available Many factors influence the positioning performance in WLAN RSSI fingerprinting systems, and summary of these factors is an important but challenging job. Moreover, impact analysis on nonalgorithm factors is significant to system application and quality control but little research has been conducted. This paper analyzes and summarizes the potential impact factors by using an Ishikawa diagram considering radio signal transmitting, propagating, receiving, and processing. A simulation platform was developed to facilitate the analysis experiment, and the paper classifies the potential factors into controllable, uncontrollable, nuisance, and held-constant factors considering simulation feasibility. It takes five nonalgorithm controllable factors including APs density, APs distribution, radio signal propagating attenuation factor, radio signal propagating noise, and RPs density into consideration and adopted the OFAT analysis method in experiment. The positioning result was achieved by using the deterministic and probabilistic algorithms, and the error was presented by RMSE and CDF. The results indicate that the high APs density, signal propagating attenuation factor, and RPs density, with the low signal propagating noise level, are favorable to better performance, while APs distribution has no particular impact pattern on the positioning error. Overall, this paper has made great potential contribution to the quality control of WLAN fingerprinting solutions.

  7. The Research on WLAN Technology of Chain Network Based on Monitoring Information Transmission of Catenary

    Directory of Open Access Journals (Sweden)

    Chunmei Wu

    2017-01-01

    Full Text Available The structure of railway catenary line is “long chain”. Considering each catenary as a wireless node, it will form the chain wireless network that solves the transmission problem of monitoring data on railway catenary line. Using token method to manage the distribution of channel resources can optimize the structure of “long chain”. The local system decomposes several subnet class units which consist of one or more nodes. Then the token is transmitted in denomination of subnet. The system structure is composed of multiple subnets connected in series, making the route more flexible. The network can self-repair and prevent system breakdown due to node failures. The stability of system will be enhanced. The monitoring data can be sent in parallel, and the network efficiency becomes higher. Using token as control information, nodes will not interfere with each other, thus achieving orderly utilization of the channel.

  8. Novel Adaptive QoS Framework for Integrated UMTS/WLAN Environment

    Directory of Open Access Journals (Sweden)

    T. Shuminoski

    2013-06-01

    Full Text Available Since Quality of Service (QoS provisioning for multimedia traffic in integrated Wireless and Mobile Networks is becoming an increasingly important objective, in this paper we introduce a novel concept of an adaptive QoS cross-layer framework. The Adaptive QoS framework is proven via novel simulation results in integrated environment with UMTS and IEEE 802.11 networks. The aim of our novel framework is presenting a new module that shall provide the best QoS and lower cost for a given service using one or more wireless technologies in a given time. The analysis of simulation results has shown superior performances with a high level of QoS provisioning in a variety of network conditions. The performance of Adaptive QoS algorithm is evaluated using ns-miracle augmented with our dual-mode Mobile Equipments (MEs and using statistical analysis.

  9. WLAN Hot Spot services for the automotive and oil industries :a business analysis Or : "Refuel the car with petrol and information, both ways at the gas station"

    NARCIS (Netherlands)

    L-F. Pau (Louis-François); M.H.P. Oremus

    2003-01-01

    textabstractWhile you refuel for gas ,why not refuel for information or download vehicle data ? This paper analyzes in extensive detail the user segmentation by vehicle usage , service offering , and full business models from WLAN hot spot services delivered to vehicles (private, professional ,

  10. Improving LAN Performance Based on IEEE802.1Q VLAN Switching Techniques

    Directory of Open Access Journals (Sweden)

    Dhurgham Abdulridha Jawad AL-Khaffaf

    2017-11-01

    Full Text Available VLAN is a set of users in different isolated logical LANs or broadcasting domains, they are communicated as a same LAN i.e. same broadcasting domain. Ethernet protocol is very popular over networks because it has a simple of implementation and ease of configuration. However, the support of Quality of Service (QoS has become an essential merit of Ethernet network. In this context, the problems of large network and data transport delay have been regained significant importance. Alleviating the end to end delay by using the VLAN technology to enhance the network performance. In this paper, we analyze and evaluate the performance of LAN and VLAN networks in different scenarios. Measuring key performance indicators such as traffic sent, traffic received, average delay and throughput. The simulation was carried out by employing OPNET 17.5 Student Version. Two different scenarios are presented to observe the performance of LAN and VLAN networks. The simulation results illustrated that there is more existing traffic without VLAN technology. Hence, VLANs prohibit the access to the network resources of other departments. Also, VLAN has half average queuing delay compared with no VLAN scenario. Therefore, VLANs can improve bandwidth utilization, power, speed and security.

  11. The effect of sex, slaughter weight and weight gains in PEN-AR-LAN ...

    African Journals Online (AJOL)

    ajl yemi

    2011-11-14

    Nov 14, 2011 ... animals of higher weight gains (54.2 and 53.7%). Key words: Pigs, PEN-AR-LAN, slaughter value, sex, slaughter weight, daily gain. INTRODUCTION. The rapid growth of the worldwide population has resulted in necessity of increasing the food production. In this way, the primary aim of breeding work has ...

  12. Specification for Digital Channel Selection Filters in a Bluetooth Capable HiperLAN/2 Receiver

    NARCIS (Netherlands)

    Hoeksema, F.W.; Schiphorst, Roelof; Slump, Cornelis H.

    2002-01-01

    In this paper we first briefly describe how the analog part of the channel selection function for a HiperLAN/2 receiver can be used as part of the channel selection function for a Bluetooth receiver. Thereafter we proceed to specify the overall requirements for the Bluetooth channel selection

  13. LAN (Local Area Network) Interoperability Study of Protocols Needed for Distributed Command and Control

    Science.gov (United States)

    1985-03-01

    o............... 5-28 5.5.1 General Network Architectura ........................ ..... 5-29 0405b/LAIN vii 77. TABLE OF CONTENTS (Continued...user requirements. It addresses such aspects "as: - Security "- Survivability - Endurance ’ 1761D/LAN 5-16 - Supportability - Sustainability

  14. Precision measurement of the positive muon lifetime by the MuLan collaboration

    NARCIS (Netherlands)

    Onderwater, C. J. G.

    We report the result of a measurement of the positive muon lifetime τμ to one part-per-million (ppm) by the MuLan collaboration using a low-energy pulsed muon beam and a segmented array of plastic scintillators to record over 2×1012 decay positrons. Two different in-vacuum muon-stopping targets were

  15. Practical network design techniques a complete guide for WANs and LANs

    CERN Document Server

    Held, Gilbert

    2004-01-01

    This new edition has two parts. The first part focuses on wide area networks; the second, which is entirely new, focuses on local area networks. Because Ethernet emerged victorious in the LAN war, the second section pays particular attention to Ethernet design and performance characteristics.

  16. Wireless mobile Internet security

    CERN Document Server

    Rhee, Man Young

    2013-01-01

      The mobile industry for wireless cellular services has grown at a rapid pace over the past decade. Similarly, Internet service technology has also made dramatic growth through the World Wide Web with a wire line infrastructure. Realization for complete wired/wireless mobile Internet technologies will become the future objectives for convergence of these technologies thr

  17. Distortion-Based Link Adaptation for Wireless Video Transmission

    Directory of Open Access Journals (Sweden)

    Andrew Nix

    2008-06-01

    Full Text Available Wireless local area networks (WLANs such as IEEE 802.11a/g utilise numerous transmission modes, each providing different throughputs and reliability levels. Most link adaptation algorithms proposed in the literature (i maximise the error-free data throughput, (ii do not take into account the content of the data stream, and (iii rely strongly on the use of ARQ. Low-latency applications, such as real-time video transmission, do not permit large numbers of retransmission. In this paper, a novel link adaptation scheme is presented that improves the quality of service (QoS for video transmission. Rather than maximising the error-free throughput, our scheme minimises the video distortion of the received sequence. With the use of simple and local rate distortion measures and end-to-end distortion models at the video encoder, the proposed scheme estimates the received video distortion at the current transmission rate, as well as on the adjacent lower and higher rates. This allows the system to select the link-speed which offers the lowest distortion and to adapt to the channel conditions. Simulation results are presented using the MPEG-4/AVC H.264 video compression standard over IEEE 802.11g. The results show that the proposed system closely follows the optimum theoretic solution.

  18. Security for multihop wireless networks

    CERN Document Server

    Khan, Shafiullah

    2014-01-01

    Security for Multihop Wireless Networks provides broad coverage of the security issues facing multihop wireless networks. Presenting the work of a different group of expert contributors in each chapter, it explores security in mobile ad hoc networks, wireless sensor networks, wireless mesh networks, and personal area networks.Detailing technologies and processes that can help you secure your wireless networks, the book covers cryptographic coprocessors, encryption, authentication, key management, attacks and countermeasures, secure routing, secure medium access control, intrusion detection, ep

  19. The wireless internet explained

    CERN Document Server

    Rhoton, John

    2001-01-01

    The Wireless Internet Explained covers the full spectrum of wireless technologies from a wide range of vendors, including initiatives by Microsoft and Compaq. The Wireless Internet Explained takes a practical look at wireless technology. Rhoton explains the concepts behind the physics, and provides an overview that clarifies the convoluted set of standards heaped together under the umbrella of wireless. It then expands on these technical foundations to give a panorama of the increasingly crowded landscape of wireless product offerings. When it comes to actual implementation the book gives abundant down-to-earth advice on topics ranging from the selection and deployment of mobile devices to the extremely sensitive subject of security.Written by an expert on Internet messaging, the author of Digital Press''s successful Programmer''s Guide to Internet Mail and X.400 and SMTP: Battle of the E-mail Protocols, The Wireless Internet Explained describes and evaluates the current state of the fast-growing and crucial...

  20. Vulnerability issues on research in WLAN encryption algorithms WEP WPA/WPA2 Personal

    International Nuclear Information System (INIS)

    Ioannis, Lazaridis; Sotirios, Pouros; Simeon, Veloudis

    2013-01-01

    This paper presents historic and new evidence that wireless encryption algorithms can be cracked or even bypassed which has been proved by other researchers. The paper presents a description of how WEP and WPA/WPA2 Personal encrypt data and how the passphrase is shared between the nodes of the network. Modern tools available on the internet have been evaluated, decomposed and tested to provide evidence on the reliability of passwords. A number of criteria are used to compare the tools and their efficiency

  1. Wireless rechargeable sensor networks

    CERN Document Server

    Yang, Yuanyuan

    2015-01-01

    This SpringerBrief provides a concise guide to applying wireless energy transfer techniques in traditional battery-powered sensor networks. It examines the benefits and challenges of wireless power including efficiency and reliability. The authors build a wireless rechargeable sensor networks from scratch and aim to provide perpetual network operation. Chapters cover a wide range of topics from the collection of energy information and recharge scheduling to joint design with typical sensing applications such as data gathering. Problems are approached using a natural combination of probability

  2. Wireless network pricing

    CERN Document Server

    Huang, Jianwei

    2013-01-01

    Today's wireless communications and networking practices are tightly coupled with economic considerations, to the extent that it is almost impossible to make a sound technology choice without understanding the corresponding economic implications. This book aims at providing a foundational introduction on how microeconomics, and pricing theory in particular, can help us to understand and build better wireless networks. The book can be used as lecture notes for a course in the field of network economics, or a reference book for wireless engineers and applied economists to understand how pricing

  3. Wireless mesh networks

    CERN Document Server

    Held, Gilbert

    2005-01-01

    Wireless mesh networking is a new technology that has the potential to revolutionize how we access the Internet and communicate with co-workers and friends. Wireless Mesh Networks examines the concept and explores its advantages over existing technologies. This book explores existing and future applications, and examines how some of the networking protocols operate.The text offers a detailed analysis of the significant problems affecting wireless mesh networking, including network scale issues, security, and radio frequency interference, and suggests actual and potential solutions for each pro

  4. Optical and wireless technologies

    CERN Document Server

    Tiwari, Manish; Singh, Ghanshyam; Minzioni, Paolo

    2018-01-01

    This book presents selected papers from 1st International Conference on Optical and Wireless Technologies, providing insights into the analytical, experimental, and developmental aspects of systems, techniques, and devices in these spheres. It explores the combined use of various optical and wireless technologies in next-generation networking applications, and discusses the latest developments in applications such as photonics, high-speed communication systems and networks, visible light communication, nanophotonics, and wireless and multiple-input-multiple-output (MIMO) systems. The book will serve as a valuable reference resource for academics and researchers across the globe.

  5. Analisa Horizontal Handover Terhadap Qos Layanan Streaming Multimedia E-Learning Pada Jaringan WLAN 802.11

    Directory of Open Access Journals (Sweden)

    I M.O. Widyantara

    2015-06-01

    Full Text Available In this globalization era, the state of the user who no longer occupies in a single place, but always moving, it is necessary to continuity of communication that will cause a handover. This paper intends to analyze the effect of 802.11 WLAN horizontal handover to the QoS of streaming e-learning. Methods of data collection process using the Cisco 3500 series access point that supports handover with existing network systems, ad-hoc network and type of hard handover. The results of the data analysis showed that the handover process is able to improve the QoS by gradually restored gradually, to get back to normal QoS

  6. Design of an ultra low power third order continuous time current mode ΣΔ modulator for WLAN applications.

    Science.gov (United States)

    Behzadi, Kobra; Baghelani, Masoud

    2014-05-01

    This paper presents a third order continuous time current mode ΣΔ modulator for WLAN 802.11b standard applications. The proposed circuit utilized feedback architecture with scaled and optimized DAC coefficients. At circuit level, we propose a modified cascade current mirror integrator with reduced input impedance which results in more bandwidth and linearity and hence improves the dynamic range. Also, a very fast and precise novel dynamic latch based current comparator is introduced with low power consumption. This ultra fast comparator facilitates increasing the sampling rate toward GHz frequencies. The modulator exhibits dynamic range of more than 60 dB for 20 MHz signal bandwidth and OSR of 10 while consuming only 914 μW from 1.8 V power supply. The FoM of the modulator is calculated from two different methods, and excellent performance is achieved for proposed modulator.

  7. Analysis And Simulation Of Low Profile Planar Inverted - F Antenna Design For WLAN Operation In Portable Devices

    Directory of Open Access Journals (Sweden)

    Zaw Htet Lwin

    2015-08-01

    Full Text Available This paper presents a compact planar invertedF antenna PIFA design for WLAN operation in portable devices. The proposed design has size of 8 x 21 mm and provides peak directive gain of 5.78dBi with the peak return loss of -33.89dB and input impedance of 50.28amp8486. It covers a 10dB return loss bandwidth of 410MHz 2.37GHz 2.789GHz. Its VSWR varies from 1.96 to 1.93 within the antenna return loss bandwidth. As the dimension of the proposed antenna is very small the antenna is promising to be embedded within the different portable devices employing WiFi applications. This paper includes the return loss as a function of frequency with varying the different parameters VSWR input resistance radiation pattern and current distribution of the proposed antenna.

  8. Design of an ultra low power third order continuous time current mode ΣΔ modulator for WLAN applications

    Directory of Open Access Journals (Sweden)

    Kobra Behzadi

    2014-05-01

    Full Text Available This paper presents a third order continuous time current mode ΣΔ modulator for WLAN 802.11b standard applications. The proposed circuit utilized feedback architecture with scaled and optimized DAC coefficients. At circuit level, we propose a modified cascade current mirror integrator with reduced input impedance which results in more bandwidth and linearity and hence improves the dynamic range. Also, a very fast and precise novel dynamic latch based current comparator is introduced with low power consumption. This ultra fast comparator facilitates increasing the sampling rate toward GHz frequencies. The modulator exhibits dynamic range of more than 60 dB for 20 MHz signal bandwidth and OSR of 10 while consuming only 914 μW from 1.8 V power supply. The FoM of the modulator is calculated from two different methods, and excellent performance is achieved for proposed modulator.

  9. Use of Time-Frequency Analysis and Neural Networks for Mode Identification in a Wireless Software-Defined Radio Approach

    Directory of Open Access Journals (Sweden)

    Matteo Gandetto

    2004-09-01

    Full Text Available The use of time-frequency distributions is proposed as a nonlinear signal processing technique that is combined with a pattern recognition approach to identify superimposed transmission modes in a reconfigurable wireless terminal based on software-defined radio techniques. In particular, a software-defined radio receiver is described aiming at the identification of two coexistent communication modes: frequency hopping code division multiple access and direct sequence code division multiple access. As a case study, two standards, based on the previous modes and operating in the same band (industrial, scientific, and medical, are considered: IEEE WLAN 802.11b (direct sequence and Bluetooth (frequency hopping. Neural classifiers are used to obtain identification results. A comparison between two different neural classifiers is made in terms of relative error frequency.

  10. OFDM and MC-CDMA for broadband multi-user communications WLANs and broadcasting

    CERN Document Server

    2003-01-01

    "OFDM systems have experienced increased attention in recent years and have found applications in a number of diverse areas including telephone-line based ADSL links, digital audio and video broadcasting systems, and wireless local area networks. OFDM is being considered for the next-generation of wireless systems both with and without direct sequence spreading and the resultant spreading-based multi-carrier CDMA systems have numerous attractive properties. This volume provides the reader with a broad overview of the research on OFDM systems during their 40-year history. Part I commences with an easy to read conceptual, rather than mathematical, treatment of the basic design issues of OFDM systems. The discussions gradually deepen to include adaptive single and multi-user OFDM systems invoking adaptive turbo coding. Part II introduces the taxonomy of multi-carrier CDMA systems and deals with the design of their spreading codes and the objective of minimising their crest factors. This part also compares the be...

  11. Research on Matrix-type Packet Loss Compensation Scheme for Wireless Video Transmission on Subway

    Directory of Open Access Journals (Sweden)

    Fan Qing-Wu

    2017-01-01

    Full Text Available As the mainstream wireless LAN technology, Wi-Fi can achieve fast data transfer. With the subway moving in a high speed, video data transmission between the metro and the ground is achieved through Wi-Fi technology. This paper aims at solving the Caton problem caused by switching packet loss in the process of playing real-time video on the train terminal, and proposes matrix-type packet loss compensation scheme. Finally, the feasibility of the scheme is verified by experiments.

  12. Detection of Spoofed MAC Addresses in 802.11 Wireless Networks

    Science.gov (United States)

    Tao, Kai; Li, Jing; Sampalli, Srinivas

    Medium Access Control (MAC) address spoofing is considered as an important first step in a hacker's attempt to launch a variety of attacks on 802.11 wireless networks. Unfortunately, MAC address spoofing is hard to detect. Most current spoofing detection systems mainly use the sequence number (SN) tracking technique, which has drawbacks. Firstly, it may lead to an increase in the number of false positives. Secondly, such techniques cannot be used in systems with wireless cards that do not follow standard 802.11 sequence number patterns. Thirdly, attackers can forge sequence numbers, thereby causing the attacks to go undetected. We present a new architecture called WISE GUARD (Wireless Security Guard) for detection of MAC address spoofing on 802.11 wireless LANs. It integrates three detection techniques - SN tracking, Operating System (OS) fingerprinting & tracking and Received Signal Strength (RSS) fingerprinting & tracking. It also includes the fingerprinting of Access Point (AP) parameters as an extension to the OS fingerprinting for detection of AP address spoofing. We have implemented WISE GUARD on a test bed using off-the-shelf wireless devices and open source drivers. Experimental results show that the new design enhances the detection effectiveness and reduces the number of false positives in comparison with current approaches.

  13. A LAN with real-time facilities based on OSI concepts

    International Nuclear Information System (INIS)

    Raaf, A.J. de; Dijkstra, A.; Swierstra, S.D.

    1986-01-01

    Research is being done into structured design and realization methods for Local Area Networks (LAN's). The main aim is to develop a LAN (ZWOLAN) with real-time facilities for use in laboratories and based on ISO-OSI standards. Twentenet will be used for the physical and the data link layer of ZWOLAN. Twentenet is based on a Priority based CSMA/CD data link access mechanism with guaranteed access times. An implementation model has been constructed from an FSM decomposition analysis of OSI protocols. Modular Pascal will be used as language for the realization of the network software. The emphasis is on the software architecture and the reduction of the OSI protocol overhead. (Auth.)

  14. Marketing de Novos Produtos: Lançamento e Inovação

    Directory of Open Access Journals (Sweden)

    Adriana Conceicao Dutra

    2014-12-01

    Full Text Available Atualmente as empresas lançam um produto com o objetivo de permanecerem por mais tempo no mercado. Embora muitas empresas fracassassem ao lançarem um produto, seria um mito dizer que as maiorias dos novos produtos fracassam ou que seu sucesso vai de acordo com sua atratividade. A modernização traz consigo as premissas, a eficiência, a qualidade e a produtividade, que de certa forma impõem uma carga à sociedade como um todo. Superar as expectativas dos consumidores, por meio de produtos e serviços inovadores, assegura vantagens competitivas e permite às empresas a ocupação de posições de liderança, em mercados altamente competitivos.

  15. Cross-layer based adaptive wireless traffic control for per-flow and per-station fairness

    Directory of Open Access Journals (Sweden)

    Siwamogsatham Siwaruk

    2011-01-01

    Full Text Available Abstract In the IEEE 802.11 wireless LANs, the bandwidth is not fairly shared among stations due to the distributed coordination function (DCF mechanism in the IEEE 802.11 MAC protocol. It introduces the per-flow and per-station unfairness problems between uplink and downlink flows, as the uplink flows usually dominate the downlink flows. In addition, some users may use greedy applications such as video streaming, which may prevent other applications from connecting to the Internet. In this article, we propose an adaptive cross-layer bandwidth allocation mechanism to provide per-station and per-flow fairness. To verify the effectiveness and scalability, our scheme is implemented on a wireless access router and numerous experiments in a typical wireless environment with both TCP and UDP traffic are conducted to evaluate performance of the proposed scheme.

  16. Wireless capsule endoscopy

    Science.gov (United States)

    Iddan, Gavriel; Meron, Gavriel; Glukhovsky, Arkady; Swain, Paul

    2000-05-01

    We have developed a new type of endoscopy, which for the first time allows painless endoscopic imaging of the whole of the small bowel. This procedure involves a wireless capsule endoscope and we describe here its successful testing in humans.

  17. Green heterogeneous wireless networks

    CERN Document Server

    Ismail, Muhammad; Nee, Hans-Peter; Qaraqe, Khalid A; Serpedin, Erchin

    2016-01-01

    This book focuses on the emerging research topic "green (energy efficient) wireless networks" which has drawn huge attention recently from both academia and industry. This topic is highly motivated due to important environmental, financial, and quality-of-experience (QoE) considerations. Specifically, the high energy consumption of the wireless networks manifests in approximately 2% of all CO2 emissions worldwide. This book presents the authors’ visions and solutions for deployment of energy efficient (green) heterogeneous wireless communication networks. The book consists of three major parts. The first part provides an introduction to the "green networks" concept, the second part targets the green multi-homing resource allocation problem, and the third chapter presents a novel deployment of device-to-device (D2D) communications and its successful integration in Heterogeneous Networks (HetNets). The book is novel in that it specifically targets green networking in a heterogeneous wireless medium, which re...

  18. The effect of sex, slaughter weight and weight gains in PEN-AR-LAN ...

    African Journals Online (AJOL)

    The aim of the study was to determine the effect of sex, body weight and growth rates on basic fattening and slaughter indexes in PEN-AR-LAN fatteners. The research was conducted on 274 PEN-ARLAN hybrid fatteners coming from sows of the Naïma maternal line and was sired by boars of the P-76 meat line. Recorded ...

  19. Networking issues---Lan and Wan needs---The impact of workstations

    International Nuclear Information System (INIS)

    Harvey, J.

    1990-01-01

    This review focuses on the use of networks in the LEP experiments at CERN. The role of the extended LAN at CERN is discussed in some detail, with particular emphasis on the impact the sudden growth in the use of workstations is having. The problem of network congestion is highlighted and possible evolution to FDDI mentioned. The status and use of the wide area connections are also reported

  20. Compact printed high rejection triple band-notch UWB antenna with multiple wireless applications

    Directory of Open Access Journals (Sweden)

    Manish Sharma

    2016-09-01

    Full Text Available In this paper, small printed urn-shape triple notch ultra-wideband (UWB monopole antenna with diverse wireless applications is presented. Notch bands include WiMAX (IEEE802.16 3.30–3.80 GHz, WLAN IEEE802.11a/h/j/n (5.15–5.35 GHz, 5.25–5.35 GHz, 5.47–5.725 GHz, 5.725–5.825 GHz, and X-band downlink satellite system (7.25–7.75 GHz and other multiple wireless services as close range radar (8–12 GHz in X-band & satellite communication (12–18 GHz in Ku-band. By including T-shape stub and etching two C-shaped slots on the radiating patch, triple band-notch function is obtained with measured high band rejection (VSWR = 16.54 at 3.60 GHz, VSWR = 22.35 at 5.64 GHz and VSWR = 6.38 at 7.64 GHz and covers a wide useable fractional bandwidth of 154.56% (2.49–19.41 GHz. In short the antenna offers triple band-notch UWB systems as a compact multifunctional antenna to reduce the number of antennas installed in wireless devices for accessing multiple wireless networks with wide radiation pattern.

  1. Wireless radio a history

    CERN Document Server

    Coe, Lewis

    2006-01-01

    ""Informative...recommended""--Choice; ""interesting...a good read...well worth reading""--Contact Magazine. This history first looks at Marconi's wireless communications system and then explores its many applications, including marine radio, cellular telephones, police and military uses, television and radar. Radio collecting is also discussed, and brief biographies are provided for the major figures in the development and use of the wireless.

  2. Wireless Networks Security

    OpenAIRE

    Jenko, Marko

    2016-01-01

    In this thesis we deal with security, penetration testing and different types of attacks on wireless networks. We theoretically familiarize with the field of wireless networks, security mechanisms and the most used security standards. Then we systematically overview the field of penetration testing. We divide the penetration testing on types and different methodologies. We explain the tasks of the provider and the subscriber in penetration testing. Description of the process of conducting the...

  3. Wireless networks of opportunity in support of secure field operations

    Science.gov (United States)

    Stehle, Roy H.; Lewis, Mark

    1997-02-01

    Under funding from the Defense Advanced Research Projects Agency (DARPA) for joint military and law enforcement technologies, demonstrations of secure information transfer in support of law enforcement and military operations other than war, using wireless and wired technology, were held in September 1996 at several locations in the United States. In this paper, the network architecture, protocols, and equipment supporting the demonstration's scenarios are presented, together with initial results, including lessons learned and desired system enhancements. Wireless networks of opportunity encompassed in-building (wireless-LAN), campus-wide (Metricom Inc.), metropolitan (AMPS cellular, CDPD), and national (one- and two-way satellite) systems. Evolving DARPA-sponsored packet radio technology was incorporated. All data was encrypted, using multilevel information system security initiative (MISSI)FORTEZZA technology, for carriage over unsecured and unclassified commercial networks. The identification and authentication process inherent in the security system permitted logging for database accesses and provided an audit trail useful in evidence gathering. Wireless and wireline communications support, to and between modeled crisis management centers, was demonstrated. Mechanisms for the guarded transport of data through the secret-high military tactical Internet were included, to support joint law enforcement and crisis management missions. A secure World Wide Web (WWW) browser forms the primary, user-friendly interface for information retrieval and submission. The WWW pages were structured to be sensitive to the bandwidth, error rate, and cost of the communications medium in use (e.g., the use of and resolution for graphical data). Both still and motion compressed video were demonstrated, along with secure voice transmission from laptop computers in the field. Issues of network bandwidth, airtime costs, and deployment status are discussed.

  4. OTENTIKASI USER PADA JARINGAN WLAN BERBASIS MIKROTIK OS DI SMP NEGERI 3 PURWOKERTO

    Directory of Open Access Journals (Sweden)

    Eko Rujianto Saputro

    2008-02-01

    Full Text Available Tujuan dari penelitian ini adalah untuk untuk menerapkan MikroTik Os sebagai router untuk otentikasi dan pengaturan bandwidth pada MikroTik Os dalam membangun jaringan wireless. Metode yang digunakan menggunakan metode eksperimental. Studi kasus pada SMP Negeri 3 Purwokerto. Hasil dari penelitian menunjukan bahwa penerapan fasilitas hotspot pada Mikrotik Router dapat membatasi akses user yang terkoneksi dengan jaringan SMP Negeri 3 Purwokerto sehingga user yang tidak memiliki hak akses tidak dapat masuk ke dalam jaringan. Dengan melakukan manajemen bandwidth pada jaringan SMP Negeri 3 Purwokerto maka tidak lagi terjadi kasus pemakaian bandwidth secara berlebihan oleh single user. Sehingga semua user mendapat jatah bandwidth yang sama dengan perioritas jam sibuk di lab komputer

  5. The Village Telco project: a reliable and practical wireless mesh telephony infrastructure

    Directory of Open Access Journals (Sweden)

    Gardner-Stephen Paul

    2011-01-01

    Full Text Available Abstract VoIP (Voice over IP over mesh networks could be a potential solution to the high cost of making phone calls in most parts of Africa. The Village Telco (VT is an easy to use and scalable VoIP over meshed WLAN (Wireless Local Area Network telephone infrastructure. It uses a mesh network of mesh potatoes to form a peer-to-peer network to relay telephone calls without landlines or cell phone towers. This paper discusses the Village Telco infrastructure, how it addresses the numerous difficulties associated with wireless mesh networks, and its efficient deployment for VoIP services in some communities around the globe. The paper also presents the architecture and functions of a mesh potato and a novel combined analog telephone adapter (ATA and WiFi access point that routes calls. Lastly, the paper presents the results of preliminary tests that have been conducted on a mesh potato. The preliminary results indicate very good performance and user acceptance of the mesh potatoes. The results proved that the infrastructure is deployable in severe and under-resourced environments as a means to make cheap phone calls and render Internet and IP-based services. As a result, the VT project contributes to bridging the digital divide in developing areas.

  6. RACOON: a multiuser QoS design for mobile wireless body area networks.

    Science.gov (United States)

    Cheng, Shihheng; Huang, Chingyao; Tu, Chun Chen

    2011-10-01

    In this study, Random Contention-based Resource Allocation (RACOON) medium access control (MAC) protocol is proposed to support the quality of service (QoS) for multi-user mobile wireless body area networks (WBANs). Different from existing QoS designs that focus on a single WBAN, a multiuser WBAN QoS should further consider both inter-WBAN interference and inter-WBAN priorities. Similar problems have been studied in both overlapped wireless local area networks (WLANs) and Bluetooth piconets that need QoS supports. However, these solutions are designed for non-medical transmissions that do not consider any priority scheme for medical applications. Most importantly, these studies focus on only static or low mobility networks. Network mobility of WBANs will introduce unnecessary inter-network collisions and energy waste, which are not considered by these solutions. The proposed multiuser-QoS protocol, RACOON, simultaneously satisfies the inter WBAN QoS requirements and overcomes the performance degradation caused by WBAN mobility. Simulation results verify that RACOON provides better latency and energy control, as compared with WBAN QoS protocols without considering the inter-WBAN requirements.

  7. A Double-Negative Metamaterial-Inspired Mobile Wireless Antenna for Electromagnetic Absorption Reduction

    Directory of Open Access Journals (Sweden)

    Touhidul Alam

    2015-07-01

    Full Text Available A double-negative metamaterial-inspired antenna is presented for mobile wireless applications. The antenna consists of a semi-circular radiating patch and a 3 × 4 hexagonal shaped metamaterial unit cell array in the ground plane. The antenna is fed with a 50 Ω microstrip feed line. The electric dimensions of the proposed antenna are 0.20λ × 0.26λ × 0.004λ, at the low-end frequency. The proposed antenna achieves a −10 dB impedance with a bandwidth of 2.29 GHz at the lower band and 1.28 GHz at the upper band and can operate for most of the mobile applications such as upper GSM bands, WiMAX, Bluetooth, and wireless local area network (WLAN frequency bands. The focused novelties of the proposed antenna are its small size, multi-standard operating bands, and electromagnetic absorption reduction at all the operating frequencies using the double-negative metamaterial ground plane.

  8. A Comparative Survey of Adaptive Codec Solutions for VoIP over Multirate WLANs: A Capacity versus Quality Performance Trade-Off

    Directory of Open Access Journals (Sweden)

    Sfairopoulou A

    2011-01-01

    Full Text Available In multi-rate WLANs, users can suffer transmission rate changes due to the link adaptation mechanism. This results in a variable capacity channel, which is very hostile for VoIP and can cause serious quality of service (QoS degradation in all active calls. Various codec adaptation mechanisms have been proposed as a solution to this, as well as to solve congestion problems on WLAN environments. Here, these solutions are presented, categorized according to the adaptation policy and scenario they implement, and evaluated at call-level in terms of the resulting blocking and dropping probabilities, as well as the perceived voice quality. To define a common performance metric, a new index named VGoS-factor is presented, which, by combining these capacity and quality indicators, can provide an overall view of the capacity versus quality trade-off of the proposed mechanisms and consequently help in choosing the adequate policy for each scenario.

  9. OPTICAL WIRELESS COMMUNICATION SYSTEM

    Directory of Open Access Journals (Sweden)

    JOSHUA L.Y. CHIENG

    2016-02-01

    Full Text Available The growing demand of bandwidth in this modern internet age has been testing the existing telecommunication infrastructures around the world. With broadband speeds moving towards the region of Gbps and Tbps, many researches have begun on the development of using optical wireless technology as feasible and future methods to the current wireless technology. Unlike the existing radio frequency wireless applications, optical wireless uses electromagnetic spectrums that are unlicensed and free. With that, this project aim to understand and gain better understanding of optical wireless communication system by building an experimental and simulated model. The quality of service and system performance will be investigated and reviewed. This project employs laser diode as the propagation medium and successfully transferred audio signals as far as 15 meters. On its quality of service, results of the project model reveal that the bit error rate increases, signal-to-noise ratio and quality factor decreases as the link distance between the transmitter and receiver increases. OptiSystem was used to build the simulated model and MATLAB was used to assist signal-to-noise ratio calculations. By comparing the simulated and experimental receiver’s power output, the experimental model’s efficiency is at 66.3%. Other than the system’s performance, challenges and factors affecting the system have been investigated and discussed. Such challenges include beam divergence, misalignment and particle absorption.

  10. EXPERIMENTAL PERFORMANCE ANALYSIS OF WIRELESS ...

    African Journals Online (AJOL)

    ABSTRACT. Wireless networking is currently being deployed for various applications. However, the application of wireless networking in healthcare remains a challenge mainly because of security and reliability concerns. This paper presents experimental results of performance analysis of a wireless network for healthcare ...

  11. Fiber wireless networks

    Science.gov (United States)

    Nirmalathas, A.; Bakaul, M.; Lim, C.; Novak, D.; Waterhouse, R.

    2005-11-01

    Broadband wireless networks based on a number of new frequency windows at higher microwave and millimeter-wave frequencies have been actively pursued to provide ultra-high bandwidth services over a wireless networks. These networks will have a large number of antenna base-stations with high throughput. Significant reductions in antenna base-station complexity can be achieved if most of the signal routing and switching functions centralized at a central office in the network. In such a network, fiber feed networks can be effectively deployed to provide high bandwidth interconnections between multiple antenna base-stations and the central office. With wavelength division multiplexing, efficient optical fiber feed network architectures could be realised to provide interconnection to a large number of antenna base-stations. In this paper, we present an over view of our recent research into system technologies for fiber wireless networks.

  12. Wireless physical layer security

    Science.gov (United States)

    Poor, H. Vincent; Schaefer, Rafael F.

    2017-01-01

    Security in wireless networks has traditionally been considered to be an issue to be addressed separately from the physical radio transmission aspects of wireless systems. However, with the emergence of new networking architectures that are not amenable to traditional methods of secure communication such as data encryption, there has been an increase in interest in the potential of the physical properties of the radio channel itself to provide communications security. Information theory provides a natural framework for the study of this issue, and there has been considerable recent research devoted to using this framework to develop a greater understanding of the fundamental ability of the so-called physical layer to provide security in wireless networks. Moreover, this approach is also suggestive in many cases of coding techniques that can approach fundamental limits in practice and of techniques for other security tasks such as authentication. This paper provides an overview of these developments.

  13. Energy efficiency in hybrid mobile and wireless networks

    Energy Technology Data Exchange (ETDEWEB)

    Ziaul Haq Abbas

    2012-07-01

    Wireless Internet access is almost pervasive nowadays, and many types of wireless networks can be used to access the Internet. However, along with this growth, there is an even greater concern about the energy consumption and efficiency of mobile devices as well as of the supporting networks, triggering the appearance of the concept of green communication. While some efforts have been made towards this direction, challenges still exist and need to be tackled from diverse perspectives. Cellular networks, WLANs, and ad hoc networks in the form of wireless mesh networks are the most popular technologies for wireless Internet access. The availability of such a variety of access networks has also paved the way to explore synergistic approaches for Internet access, leading to the concept of hybrid networks and relay communications. In addition, many mobile devices are being equipped with multiple interfaces, enabling them to operate in hybrid networks. In contrast, the improvements in the battery technology itself have not matched the pace of the emerging mobile applications. The situation becomes more sophisticated when a mobile device functions also as a relay node to forward other station's data. In the literature, energy efficiency of mobile devices has been addressed from various perspectives such as protocol-level efforts, battery management efforts, etc. However, there is little work on energy efficiency in hybrid mobile and wireless networks and devices with heterogeneous connections. For example, when there are multiple networks available to a mobile device, how to achieve optimum long-term energy consumption of such a device is an open question. Furthermore, in today's cellular networks, micro-, pico-, and femto-cells are the most popular network topologies in order to support high data rate services and high user density. With the growth of such small-cell solutions, the energy consumption of these networks is also becoming an important concern for operators

  14. Terabit Wireless Communication Challenges

    Science.gov (United States)

    Hwu, Shian U.

    2012-01-01

    This presentation briefly discusses a research effort on Terabit Wireless communication systems for possible space applications. Recently, terahertz (THz) technology (300-3000 GHz frequency) has attracted a great deal of interest from academia and industry. This is due to a number of interesting features of THz waves, including the nearly unlimited bandwidths available, and the non-ionizing radiation nature which does not damage human tissues and DNA with minimum health threat. Also, as millimeter-wave communication systems mature, the focus of research is, naturally, moving to the THz range. Many scientists regard THz as the last great frontier of the electromagnetic spectrum, but finding new applications outside the traditional niches of radio astronomy, Earth and planetary remote sensing, and molecular spectroscopy particularly in biomedical imaging and wireless communications has been relatively slow. Radiologists find this area of study so attractive because t-rays are non-ionizing, which suggests no harm is done to tissue or DNA. They also offer the possibility of performing spectroscopic measurements over a very wide frequency range, and can even capture signatures from liquids and solids. According to Shannon theory, the broad bandwidth of the THz frequency bands can be used for terabit-per-second (Tb/s) wireless communication systems. This enables several new applications, such as cell phones with 360 degrees autostereoscopic displays, optic-fiber replacement, and wireless Tb/s file transferring. Although THz technology could satisfy the demand for an extremely high data rate, a number of technical challenges need to be overcome before its development. This presentation provides an overview the state-of-the- art in THz wireless communication and the technical challenges for an emerging application in Terabit wireless systems. The main issue for THz wave propagation is the high atmospheric attenuation, which is dominated by water vapor absorption in the THz

  15. First results from the MuLan and MuCap experiments

    International Nuclear Information System (INIS)

    Banks, T. I.

    2008-01-01

    MuLan and MuCap are ongoing experiments at the Paul Scherrer Institut, Switzerland, that use the muon lifetime to determine fundamental weak interaction parameters. The goal of MuLan is a 1 ppm measurement of the positive muon lifetime τ μ + to determine the Fermi constant G F to 0.5 ppm. The goal of MuCap is to make a 1% determination of the rate Λ S of the process of nuclear muon capture by the proton, μp→nν, by measuring the μ - disappearance rate in hydrogen gas to 10 ppm and subtracting the world average for the μ + decay rate. A 1% determination of the capture rate Λ S is of interest because it would enable a 7% determination of g P , the induced pseudoscalar coupling of the nucleon. In 2007, both experiments published first results based upon data collected by each in 2004. MuLan reported an 11 ppm μ + lifetime measurement, τ μ + = 2.197 013(24) μs, resulting in a new, 9.6 ppm world average, τ μ + = 2.197 019(21) μs, which determines the Fermi constant, G F = 1.166 371(6)x10 -5 GeV -2 , to 5 ppm. MuCap reported a 3% measurement of the muon capture rate from the hyperfine singlet ground state of the μp atom, Λ S = 725.0±17.4 s -1 , from which a 15% value for the pseudoscalar coupling, g P (q 2 = -0.88m μ 2 ) = 7.3±1.1, was extracted

  16. First results from the MuLan and MuCap experiments

    Science.gov (United States)

    Banks, T. I.

    2008-02-01

    MuLan and MuCap are ongoing experiments at the Paul Scherrer Institut, Switzerland, that use the muon lifetime to determine fundamental weak interaction parameters. The goal of MuLan is a 1 ppm measurement of the positive muon lifetime τμ+ to determine the Fermi constant GF to 0.5 ppm. The goal of MuCap is to make a 1% determination of the rate ΛS of the process of nuclear muon capture by the proton, μp→nν, by measuring the μ- disappearance rate in hydrogen gas to 10 ppm and subtracting the world average for the μ+ decay rate. A 1% determination of the capture rate ΛS is of interest because it would enable a 7% determination of gP, the induced pseudoscalar coupling of the nucleon. In 2007, both experiments published first results based upon data collected by each in 2004. MuLan reported an 11 ppm μ+ lifetime measurement, τμ+ = 2.197 013(24) μs, resulting in a new, 9.6 ppm world average, τμ+ = 2.197 019(21) μs, which determines the Fermi constant, GF = 1.166 371(6)×10-5 GeV-2, to 5 ppm. MuCap reported a 3% measurement of the muon capture rate from the hyperfine singlet ground state of the μp atom, ΛS = 725.0±17.4 s-1, from which a 15% value for the pseudoscalar coupling, gP(q2 = -0.88mμ2) = 7.3±1.1, was extracted.

  17. Karacaoğlan'ın Şiirlerinde Dağ Algısı Perception Of Mountains In The Poetry Of Karacaoğlan

    Directory of Open Access Journals (Sweden)

    Işıl ALTUN

    2013-01-01

    Full Text Available Nature and “Mountains”, which are the most important elements of the nature, are important settings of the folk literature and folk poetry. Mountains in the folk poetry are a real vital part of the nature; they are not fictional settings. In the present study, five hundred poems of Karacaoğlan, who is one of the important representatives of the folk poetry and defined as the poet of love and nature, were taken into consideration. In the poetry he composed, the lives of the Turkomans which were decorated with time and place depending on their socio-cultural structures are depicted. The names of the places Karacaoğlan was brought up and visited (provinces, villages, mountains, plateaus, mountain passes, plains, lakes, springs, the language he used (descriptions, methaphores, local uses, and the traditions, customs and clothing of the Turkomans, their nomadic culture, social and historical events shed light on Karacaoğlan’s both natural and arranged environment, shortly, his living space. We see within the general nature of Karacaoğlan’s poetry that “Mountains “are very important elements of the nature. “Mountains” in Karacaoglan’s poetry characterize both a “mountain” as a part of the nature and a “mountain” depicted by him to tell what he wanted to tell. Karacaoğlan always used the nature in general sense and a “mountain” in a special and narrow sense in the context of its relationship with people. The present study emphasized how Karacaoglan told us his inner world, internal-intellectual life concept, character and excitement, discussed how Karacaoglan presented the objects, expressed his feelings by using his perception of mountains and revealed the relationship of “a mountain”, which is a spatial phenomenon and perception, with a human . Tabiat ve tabiatın en önemli unsuru olan “dağ” halk edebiyatının ve halk şairlerinin önemli mekânlarından biridir. Halk şiirinde dağ, tabiat bütünü i

  18. Security Audit of WLAN Networks Using Statistical Models of Specified Language Group

    Directory of Open Access Journals (Sweden)

    KREKAN Jan

    2013-05-01

    Full Text Available In order to build a secure computing environment, persons responsible for data security need tools which allow them to test the security of data being protected. Research of passwords, used in usual computing environments, showed that easy to remember non-dictionary passwords are widely used. So it should be useful to build a statistical model,which can then be used to create very effective password lists for testing the security of a given protected data object. The problem is that the society from specified location is using also foreign words,from languages widely used. This article describes a comparison of different language models used for this new statistical candidates generation method. This generator could be then used to test the strength of passwords used to protect wireless networks which useWPA-PSK as its data encryption standard. The password candidates passed to tools which perform the security audit. This method could be described also as sorting of Brute-force password candidates usingknowledge about languages used by the users. The tests showed that using combination of language models (MIX of specified language group for the password candidates’ generator could improve thespeed of the security procedure by 37% relatively in average (60% speedup when finding 50% of passwords – in 0.69% vs 1.715% of Bruteforce combinations comparing to mother language model (SK and 20 times average absolute speedup comparing to Bruteforce.

  19. Experimental Optimization of Exposure Index and Quality of Service in Wlan Networks.

    Science.gov (United States)

    Plets, David; Vermeeren, Günter; Poorter, Eli De; Moerman, Ingrid; Goudos, Sotirios K; Luc, Martens; Wout, Joseph

    2017-07-01

    This paper presents the first real-life optimization of the Exposure Index (EI). A genetic optimization algorithm is developed and applied to three real-life Wireless Local Area Network scenarios in an experimental testbed. The optimization accounts for downlink, uplink and uplink of other users, for realistic duty cycles, and ensures a sufficient Quality of Service to all users. EI reductions up to 97.5% compared to a reference configuration can be achieved in a downlink-only scenario, in combination with an improved Quality of Service. Due to the dominance of uplink exposure and the lack of WiFi power control, no optimizations are possible in scenarios that also consider uplink traffic. However, future deployments that do implement WiFi power control can be successfully optimized, with EI reductions up to 86% compared to a reference configuration and an EI that is 278 times lower than optimized configurations under the absence of power control. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. WLAN Cell Handoff Latency Abatement Using an FPGA Fuzzy Logic Algorithm Implementation

    Directory of Open Access Journals (Sweden)

    Roberto Sepúlveda

    2012-01-01

    Full Text Available Following the path toward 4 G set by its wireless siblings LTE and WiMax, IEEE 802.11 technology, universally known as WiFi, is evolving to become a high data rate QoS-enabled mobile platform. The IEEE 802.11n standard yields data rates up to 450 Mbp s and the 802.11e standard ensures proficient QoS for real-time applications. Still in need of better performance, multicell environments that provide extended coverage allow the mobile station nomadic passage beyond a single cell by means of cell dissociation-association process known as handoff. This process poses a challenge for real-time applications like voice over IP (150 ms maximum delay and video (200–400 ms sessions, to give the user a seamless cell-crossing without data loss or session breakage. It presented an approach of a predictive fuzzy Logic controller to reduce the channel scanning process to a tenth of the standard time, and its efficient FPGA implementation to speed up the processing time. The algorithm of the fuzzy controller was implemented in C language. Experimental results are provided.

  1. Distributed Fair Auto Rate Medium Access Control for IEEE 802.11 Based WLANs

    Science.gov (United States)

    Zhu, Yanfeng; Niu, Zhisheng

    Much research has shown that a carefully designed auto rate medium access control can utilize the underlying physical multi-rate capability to exploit the time-variation of the channel. In this paper, we develop a simple analytical model to elucidate the rule that maximizes the throughput of RTS/CTS based multi-rate wireless local area networks. Based on the discovered rule, we propose two distributed fair auto rate medium access control schemes called FARM and FARM+ from the view-point of throughput fairness and time-share fairness, respectively. With the proposed schemes, after receiving a RTS frame, the receiver selectively returns the CTS frame to inform the transmitter the maximum feasible rate probed by the signal-to-noise ratio of the received RTS frame. The key feature of the proposed schemes is that they are capable of maintaining throughput/time-share fairness in asymmetric situation where the distribution of SNR varies with stations. Extensive simulation results show that the proposed schemes outperform the existing throughput/time-share fair auto rate schemes in time-varying channel conditions.

  2. Wireless communications algorithmic techniques

    CERN Document Server

    Vitetta, Giorgio; Colavolpe, Giulio; Pancaldi, Fabrizio; Martin, Philippa A

    2013-01-01

    This book introduces the theoretical elements at the basis of various classes of algorithms commonly employed in the physical layer (and, in part, in MAC layer) of wireless communications systems. It focuses on single user systems, so ignoring multiple access techniques. Moreover, emphasis is put on single-input single-output (SISO) systems, although some relevant topics about multiple-input multiple-output (MIMO) systems are also illustrated.Comprehensive wireless specific guide to algorithmic techniquesProvides a detailed analysis of channel equalization and channel coding for wi

  3. Pervasive wireless environments

    CERN Document Server

    Yang, Jie; Trappe, Wade; Cheng, Jerry

    2014-01-01

    This Springer Brief provides a new approach to prevent user spoofing by using the physical properties associated with wireless transmissions to detect the presence of user spoofing. The most common method, applying cryptographic authentication, requires additional management and computational power that cannot be deployed consistently. The authors present the new approach by offering a summary of the recent research and exploring the benefits and potential challenges of this method. This brief discusses the feasibility of launching user spoofing attacks and their impact on the wireless and sen

  4. Wireless optical telecommunications

    CERN Document Server

    Bouchet, Olivier

    2013-01-01

    Wireless optical communication refers to communication based on the unguided propagation of optical waves. The past 30 years have seen significant improvements in this technique - a wireless communication solution for the current millennium - that offers an alternative to radio systems; a technique that could gain attractiveness due to recent concerns regarding the potential effects of radiofrequency waves on human health.The aim of this book is to look at the free space optics that are already used for the exchange of current information; its many benefits, such as incorporating chan

  5. Wireless telecommunication systems

    CERN Document Server

    Terré, Michel; Vivier, Emmanuelle

    2013-01-01

    Wireless telecommunication systems generate a huge amount of interest. In the last two decades, these systems have experienced at least three major technological leaps, and it has become impossible to imagine how society was organized without them. In this book, we propose a macroscopic approach on wireless systems, and aim at answering key questions about power, data rates, multiple access, cellular engineering and access networks architectures.We present a series of solved problems, whose objective is to establish the main elements of a global link budget in several radiocommunicati

  6. 75 FR 8400 - In the Matter of Certain Wireless Communications System Server Software, Wireless Handheld...

    Science.gov (United States)

    2010-02-24

    ... Communications System Server Software, Wireless Handheld Devices and Battery Packs; Notice of Investigation... within the United States after importation of certain wireless communications system server software... certain wireless communications system server software, wireless handheld devices or battery packs that...

  7. 75 FR 43206 - In the Matter of Certain Wireless Communications System Server Software, Wireless Handheld...

    Science.gov (United States)

    2010-07-23

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-706] In the Matter of Certain Wireless Communications System Server Software, Wireless Handheld Devices and Battery Packs: Notice of Commission... United States after importation of certain wireless communications system server software, wireless...

  8. Real-time video streaming in mobile cloud over heterogeneous wireless networks

    Science.gov (United States)

    Abdallah-Saleh, Saleh; Wang, Qi; Grecos, Christos

    2012-06-01

    Recently, the concept of Mobile Cloud Computing (MCC) has been proposed to offload the resource requirements in computational capabilities, storage and security from mobile devices into the cloud. Internet video applications such as real-time streaming are expected to be ubiquitously deployed and supported over the cloud for mobile users, who typically encounter a range of wireless networks of diverse radio access technologies during their roaming. However, real-time video streaming for mobile cloud users across heterogeneous wireless networks presents multiple challenges. The network-layer quality of service (QoS) provision to support high-quality mobile video delivery in this demanding scenario remains an open research question, and this in turn affects the application-level visual quality and impedes mobile users' perceived quality of experience (QoE). In this paper, we devise a framework to support real-time video streaming in this new mobile video networking paradigm and evaluate the performance of the proposed framework empirically through a lab-based yet realistic testing platform. One particular issue we focus on is the effect of users' mobility on the QoS of video streaming over the cloud. We design and implement a hybrid platform comprising of a test-bed and an emulator, on which our concept of mobile cloud computing, video streaming and heterogeneous wireless networks are implemented and integrated to allow the testing of our framework. As representative heterogeneous wireless networks, the popular WLAN (Wi-Fi) and MAN (WiMAX) networks are incorporated in order to evaluate effects of handovers between these different radio access technologies. The H.264/AVC (Advanced Video Coding) standard is employed for real-time video streaming from a server to mobile users (client nodes) in the networks. Mobility support is introduced to enable continuous streaming experience for a mobile user across the heterogeneous wireless network. Real-time video stream packets

  9. Resource management in wireless networking

    CERN Document Server

    Cardei, Mihaela; Du, Ding-Zhu

    2005-01-01

    This is the first book that provides readers with a deep technical overview of recent advances in resource management for wireless networks at different layers of the protocol stack. The subject is explored in various wireless networks, such as ad hoc wireless networks, 3G/4G cellular, IEEE 802.11, and Bluetooth personal area networks.Survey chapters give an excellent introduction to key topics in resource management for wireless networks, while experts will be satisfied by the technical depth of the knowledge imparted in chapters exploring hot research topics.The subject area discussed in this book is very relevant today, considering the recent remarkable growth of wireless networking and the convergence of wireless personal communications, internet technologies and real-time multimedia.This volume is a very good companion for practitioners working on implementing solutions for multimedia and Quality of Service - sensitive applications over wireless networks.Written for:Researchers, faculty members, students...

  10. Wireless Distributed Antenna MIMO

    DEFF Research Database (Denmark)

    2015-01-01

    The present disclosure relates to system applications of multicore optical fibers. One embodiment relates to a base transceiver station for a wireless telecommunication system comprising a plurality of antenna units arranged in a MIMO configuration and adapted for transmission and/or reception...

  11. Networking wireless sensors

    National Research Council Canada - National Science Library

    Krishnamachari, Bhaskar

    2005-01-01

    ... by networking techniques across multiple layers. The topics covered include network deployment, localization, time synchronization, wireless radio characteristics, medium-access, topology control, routing, data-centric techniques, and transport protocols. Ideal for researchers and designers seeking to create new algorithms and protocols and enginee...

  12. Wireless Remote Control System

    Directory of Open Access Journals (Sweden)

    Adrian Tigauan

    2012-06-01

    Full Text Available This paper presents the design of a wireless remote control system based on the ZigBee communication protocol. Gathering data from sensors or performing control tasks through wireless communication is advantageous in situations in which the use of cables is impractical. An Atmega328 microcontroller (from slave device is used for gathering data from the sensors and transmitting it to a coordinator device with the help of the XBee modules. The ZigBee standard is suitable for low-cost, low-data-rate and low-power wireless networks implementations. The XBee-PRO module, designed to meet ZigBee standards, requires minimal power for reliable data exchange between devices over a distance of up to 1600m outdoors. A key component of the ZigBee protocol is the ability to support networking and this can be used in a wireless remote control system. This system may be employed e.g. to control temperature and humidity (SHT11 sensor and light intensity (TSL230 sensor levels inside a commercial greenhouse.

  13. Subsurface Wireless Sensor Networks

    Science.gov (United States)

    Niemeier, J. J.; Davies, J. L.; Kruger, A.

    2008-12-01

    Conventional thinking holds that underground- and underwater radio communication is not possible, except at very low frequencies employing very long antennas and high transmit power. However, researchers at The University of Iowa have demonstrated that using inexpensive, low-power radios, it is in fact possible to achieve reliable underground radio communication over distances of several meters. This allows for creating underground wireless sensor networks. A proof-of-concept network was established at The University of Iowa, where nodes that measure soil moisture content are buried over a 20×20 m area (up to 1 m deep). The nodes organize themselves into a wireless sensor network, reconfigure routes as radio link quality waxes and wanes, cooperate in routing data packets to a surface base station, and so on. In an agricultural research setting, an advantage of such buried wireless sensor networks is that, if nodes were buried deep enough, they may be left in place during agricultural field work. Power consumption is an important issue in wireless sensor networks. This is especially true in a buried network where battery replacement is a major undertaking. The focus of continuing research is developing methods of inductively recharging buried sensor batteries.

  14. Insecurity of Wireless Networks

    Energy Technology Data Exchange (ETDEWEB)

    Sheldon, Frederick T [ORNL; Weber, John Mark [Dynetics, Inc.; Yoo, Seong-Moo [University of Alabama, Huntsville; Pan, W. David [University of Alabama, Huntsville

    2012-01-01

    Wireless is a powerful core technology enabling our global digital infrastructure. Wi-Fi networks are susceptible to attacks on Wired Equivalency Privacy, Wi-Fi Protected Access (WPA), and WPA2. These attack signatures can be profiled into a system that defends against such attacks on the basis of their inherent characteristics. Wi-Fi is the standard protocol for wireless networks used extensively in US critical infrastructures. Since the Wired Equivalency Privacy (WEP) security protocol was broken, the Wi-Fi Protected Access (WPA) protocol has been considered the secure alternative compatible with hardware developed for WEP. However, in November 2008, researchers developed an attack on WPA, allowing forgery of Address Resolution Protocol (ARP) packets. Subsequent enhancements have enabled ARP poisoning, cryptosystem denial of service, and man-in-the-middle attacks. Open source systems and methods (OSSM) have long been used to secure networks against such attacks. This article reviews OSSMs and the results of experimental attacks on WPA. These experiments re-created current attacks in a laboratory setting, recording both wired and wireless traffic. The article discusses methods of intrusion detection and prevention in the context of cyber physical protection of critical Internet infrastructure. The basis for this research is a specialized (and undoubtedly incomplete) taxonomy of Wi-Fi attacks and their adaptations to existing countermeasures and protocol revisions. Ultimately, this article aims to provide a clearer picture of how and why wireless protection protocols and encryption must achieve a more scientific basis for detecting and preventing such attacks.

  15. Wireless networked music performance

    CERN Document Server

    Gabrielli, Leonardo

    2016-01-01

    This book presents a comprehensive overview of the state of the art in Networked Music Performance (NMP) and a historical survey of computer music networking. It introduces current technical trends in NMP and technical issues yet to be addressed. It also lists wireless communication protocols and compares these to the requirements of NMP. Practical use cases and advancements are also discussed.

  16. Compact Tri-Band Notched Characteristics UWB Antenna for WiMAX, WLAN and X-Band Applications

    Directory of Open Access Journals (Sweden)

    E. K. I. Hamad

    2017-05-01

    Full Text Available Compact microstrip-fed printed monopole antenna with triple band-notched characteristics is suggested for ultra-wideband (UWB applications. The antenna is constructed of a conventional rectangular microstrip patch antenna with partial ground plane and T-shaped strip employed in the ground plane as well as an inverted Ω- and L-shaped slots incorporated within the radiated element. The notched functions are created by the inverted Ω- and L-shaped slots, which are realized for WiMAX (from 2.69 to 4.5 GHz and WLAN (from 5.49 to 6.37 GHz. The T-shaped parasitic strip generates the third notch for the X-band uplink satellite communication (from 8.15 to 9.61 GHz. The measured operating -10 dB bandwidth of the proposed antenna extends from 2.39 to more than 18 GHz except at the notched bands. The prototype antenna has a total area of 20×20×1.6 mm3. Electromagnetic (EM simulations are carried out using 3D full-wave FEM-based simulator. EM simulation results are in good agreement with measurement results. The radiation pattern of the proposed antenna is nearly Omni-directional over the whole targeted band.

  17. KİRLİ SULARLA SULAMA YAPlLAN TOPRAKLARDA MİKROBİYAL KİRLENME

    Directory of Open Access Journals (Sweden)

    KENAN TUNÇ

    2005-01-01

    Full Text Available Bu çalışmada Kocaeli İli Derince İlçesine bağlı 11�ıu Köyü Bölgesi'nde Nisan - Mayıs 2003 ayları asında kirli sularla sulama yapılan ekili alanlarda bakteriolojik kirlilik araştırması yapılmıştır. ra�tırmamızda Slıigella (2050, E.�clıericlıia coli (1 0000, Enterobcıcter (10000 olmak üzere toplam 2�050 ba kteri gözlenmiştir. Aynı bölgedeki temiz sularda Sizige/la (50, Esclıericlıia coli görülmemiş, Enterobacter ise (300 olarak tespit edilmiştir. raştırmaınııda kirli sularta sulama yapılan ekili a l anlarda insan sağlığı üzerinde potansiyel risk oltı�turan ba kteriyoloj ik llt;.irliliğin olduğu gözlenmiştir. r Keliı11eler - Slıigella, Esclıericlıia co

  18. Extending the Capabilities of Closed-loop Distributed Engine Control Simulations Using LAN Communication

    Science.gov (United States)

    Aretskin-Hariton, Eliot D.; Zinnecker, Alicia Mae; Culley, Dennis E.

    2014-01-01

    Distributed Engine Control (DEC) is an enabling technology that has the potential to advance the state-of-the-art in gas turbine engine control. To analyze the capabilities that DEC offers, a Hardware-In-the-Loop (HIL) test bed is being developed at NASA Glenn Research Center. This test bed will support a systems-level analysis of control capabilities in closed-loop engine simulations. The structure of the HIL emulates a virtual test cell by implementing the operator functions, control system, and engine on three separate computers. This implementation increases the flexibility and extensibility of the HIL. Here, a method is discussed for implementing these interfaces by connecting the three platforms over a dedicated Local Area Network (LAN). This approach is verified using the Commercial Modular Aero-Propulsion System Simulation 40k (C-MAPSS40k), which is typically implemented on one computer. There are marginal differences between the results from simulation of the typical and the three-computer implementation. Additional analysis of the LAN network, including characterization of network load, packet drop, and latency, is presented. The three-computer setup supports the incorporation of complex control models and proprietary engine models into the HIL framework.

  19. NASA Bluetooth Wireless Communications

    Science.gov (United States)

    Miller, Robert D.

    2007-01-01

    NASA has been interested in wireless communications for many years, especially when the crew size of the International Space Station (ISS) was reduced to two members. NASA began a study to find ways to improve crew efficiency to make sure the ISS could be maintained with limited crew capacity and still be a valuable research testbed in Low-Earth Orbit (LEO). Currently the ISS audio system requires astronauts to be tethered to the audio system, specifically a device called the Audio Terminal Unit (ATU). Wireless communications would remove the tether and allow astronauts to freely float from experiment to experiment without having to worry about moving and reconnecting the associated cabling or finding the space equivalent of an extension cord. A wireless communication system would also improve safety and reduce system susceptibility to Electromagnetic Interference (EMI). Safety would be improved because a crewmember could quickly escape a fire while maintaining communications with the ground and other crewmembers at any location. In addition, it would allow the crew to overcome the volume limitations of the ISS ATU. This is especially important to the Portable Breathing Apparatus (PBA). The next generation of space vehicles and habitats also demand wireless attention. Orion will carry up to six crewmembers in a relatively small cabin. Yet, wireless could become a driving factor to reduce launch weight and increase habitable volume. Six crewmembers, each tethered to a panel, could result in a wiring mess even in nominal operations. In addition to Orion, research is being conducted to determine if Bluetooth is appropriate for Lunar Habitat applications.

  20. Channel capacity of TDD-OFDM-MIMO for multiple access points in a wireless single-frequency-network

    DEFF Research Database (Denmark)

    Takatori, Y.; Fitzek, Frank; Tsunekawa, K.

    2005-01-01

    MIMO data transmission scheme, which combines Single-Frequency-Network (SFN) with TDD-OFDM-MIMO applied for wireless LAN networks. In our proposal, we advocate to use SFN for multiple access points (MAP) MIMO data transmission. The goal of this approach is to achieve very high channel capacity in both...... LOS and non line of sight (NLOS) environments. The channel capacity of the proposed method is derived for the direct path environments and it confirms the effectiveness of the proposed scheme in the LOS scenario. Moreover, solid computer simulation results confirm the effectiveness of the proposed...

  1. ICSW2AN : An Inter-vehicle Communication System Using Mobile Access Point over Wireless Wide Area Networks

    Science.gov (United States)

    Byun, Tae-Young

    This paper presents a prototype of inter-vehicle communication system using mobile access point that internetworks wired or wireless LAN and wireless WAN anywhere. Implemented mobile access point can be equipped with various wireless WAN interfaces such as WCDMA and HSDPA. Mobile access point in the IP mechanism has to process connection setup procedure to one wireless WAN. To show the applicability of the mobile access point to inter-vehicle communication, a simplified V2I2V-based car communication system called ICSW2AN is implemented to evaluate major performance metrics by road test. In addition, results of road test for traffic information service are investigated in view of RTT, latency and server processing time. The experimental result indicates that V2I2V-based car communication system sufficiently can provide time-tolerant traffic information to moving vehicles while more than two mobile devices in restricted spaces such as car, train and ship access wireless Internet simultaneously.

  2. Design And Planning Of E- Learning EnvironmentE-Education System On Heterogeneous Wireless Network Control System

    Directory of Open Access Journals (Sweden)

    ThandarOo

    2015-06-01

    Full Text Available Abstract The purpose of this research is to provide a more efficient and effective communication method between teacher and student with the use of heterogeneous network. Moreover the effective use of heterogeneous network can be emphasized. The system of e-education can develop utilizing wireless network.The e-Education system can help students to communicate with their teacher more easily and effectively using a heterogeneous wireless network system. In this wireless network system students who are blind or dumb will also be able to communicate and learn from the teacher as normal students can do. All the devices or laptops will be connected on wireless LAN. Even when the teacher is not around he will be able to help his students with their study or give instructions easily by using the mobile phone to send text or voice signal. When the teacher sends information to the dumb student it will be converted into sign language for the student to be able to understand. When the dumb student sends the information to the teacher it will be converted into text for the teacher to understand. For the blind student text instructions from the teacher will be converted into audio signal using text-to-speech conversion.Thus the performance of heterogeneous wireless network model can evaluate by using Robust Optimization Method. Therefore the e-Education systems performance improves by evaluating Robust Optimization Method.

  3. The Lure of Wireless Encryption

    CERN Multimedia

    Computer Security Team

    2013-01-01

    Following our article entitled “Jekyll or Hyde? Better browse securely” in the last issue of the Bulletin, some people wondered why the CERN wireless network is not encrypted…   There are many arguments why it is not. The simplest is usability: the communication and management of the corresponding access keys would be challenging given the sheer number of wireless devices the CERN network hosts. Keys would quickly become public, e.g. at conferences, and might be shared, written on whiteboards, etc. Then there are all the devices which cannot be easily configured to use encryption protocols - a fact which would create plenty of calls to the CERN Service Desk… But our main argument is that wireless encryption is DECEPTIVE. Wireless encryption is deceptive as it only protects the wireless network against unauthorised access (and the CERN network already has other means to protect against that). Wireless encryption however, does not really help you. You ...

  4. Desarrollo de una aplicación de administración dinámica de una LAN

    OpenAIRE

    Varela Luque, Lluís

    2013-01-01

    Esta aplicación consiste en realizar un descubrimiento y gestión de switches cisco dentro de una LAN, para saber cuál es el estado de la red de forma rápida. Además se han de saber las características de los switches de estas redes sin tener que entrar manualmente a cada uno de ellos. Al realizar el reconocimiento de los switches de la LAN se han de guardar las características que interesen al usuario mediante OIDs y descargar los archivos de configuración. Los OIDs los ha de poder adminis...

  5. Kimyasal Kabartılan Ürünlerde Kabartma Asitlerinin Fonksiyonel Özellikleri

    Directory of Open Access Journals (Sweden)

    Önder Yıldız

    2015-02-01

    Full Text Available Kimyasal olarak kabartılan ürünlerde kullanılan kabartma tozları sodyum bikarbonat (soda ve bir ya da birden fazla kabartma asidinin birleşmesinden oluşur. Fırın ürünlerinin içyapısına katkıda bulunan koşulları ve reaksiyonları harekete geçiren kabartma asitleri tat, gözenek özelliklerini, kabuk ve iç rengini etkiler. Ayrıca, diğer bileşenler üzerine yaptıkları anyonik ve katyonik etkileşim vasıtasıyla pişmiş ürün kalitesi de değişir. Kalsiyum ve alüminyum iyonlarını içeren kabartma asitleri ince gözenek duvar kalınlığı sağlar ve glüten gelişimine katkıda bulunarak kek tekstürüne esneklik kazandırır. Sonuçta küçük hava kabarcıklarının birleşerek büyük gözenek oluşturma eğilimi azalır. Diğer yandan sülfat ve fosfatları içeren kabartma asitleri glüten gelişimini ve gaz tutulmasını olumsuz etkilerler. Her bir asidin farklı reaksiyon hızı ve CO2 salınım süresine sahip olması son ürün özelliklerine yansır. Son ürünün pH’sı da kek iç rengini etkiler. Düşük pH daha beyaz kek rengi verirken, yüksek pH daha koyu renk verir. Bu çalışmada kimyasal kabartılan ürünlerde kabartma asitlerinin fonksiyonel özellikleri tartışılacaktır.

  6. Making Wireless Networks Secure for NASA Mission Critical Applications Using Virtual Private Network (VPN) Technology

    Science.gov (United States)

    Nichols, Kelvin F.; Best, Susan; Schneider, Larry

    2004-01-01

    With so many security issues involved with wireless networks, the technology has not been fully utilized in the area of mission critical applications. These applications would include the areas of telemetry, commanding, voice and video. Wireless networking would allow payload operators the mobility to take computers outside of the control room to their off ices and anywhere else in the facility that the wireless network was extended. But the risk is too great of having someone sit just inside of your wireless network coverage and intercept enough of your network traffic to steal proprietary data from a payload experiment or worse yet hack back into your system and do even greater harm by issuing harmful commands. Wired Equivalent Privacy (WEP) is improving but has a ways to go before it can be trusted to protect mission critical data. Today s hackers are becoming more aggressive and innovative, and in order to take advantage of the benefits that wireless networking offer, appropriate security measures need to be in place that will thwart hackers. The Virtual Private Network (VPN) offers a solution to the security problems that have kept wireless networks from being used for mission critical applications. VPN provides a level of encryption that will ensure that data is protected while it is being transmitted over a wireless local area network (LAN). The VPN allows a user to authenticate to the site that the user needs to access. Once this authentication has taken place the network traffic between that site and the user is encapsulated in VPN packets with the Triple Data Encryption Standard (3DES). 3DES is an encryption standard that uses a single secret key to encrypt and decrypt data. The length of the encryption key is 168 bits as opposed to its predecessor DES that has a 56-bit encryption key. Even though 3DES is the common encryption standard for today, the Advance Encryption Standard (AES), which provides even better encryption at a lower cycle cost is growing

  7. Matching theory for wireless networks

    CERN Document Server

    Han, Zhu; Saad, Walid

    2017-01-01

    This book provides the fundamental knowledge of the classical matching theory problems. It builds up the bridge between the matching theory and the 5G wireless communication resource allocation problems. The potentials and challenges of implementing the semi-distributive matching theory framework into the wireless resource allocations are analyzed both theoretically and through implementation examples. Academics, researchers, engineers, and so on, who are interested in efficient distributive wireless resource allocation solutions, will find this book to be an exceptional resource. .

  8. An Assessment of Emerging Wireless Broadband Technologies

    National Research Council Canada - National Science Library

    Fountanas, Leonidas

    2001-01-01

    ... technologies in providing broadband services today, emerging wireless broadband technologies are expected to significantly increase their market share over the next years, Deploying a wireless network...

  9. Wireless Sensor Portal Technology Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Recognizing the needs and challenges facing NASA Earth Science for data input, manipulation and distribution, Mobitrum is proposing a ? Wireless Sensor Portal...

  10. Adaptive Wireless Transceiver, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Wireless technologies are an increasingly attractive means for spatial data, input, manipulation, and distribution. Mobitrum is proposing an innovative Adaptive...

  11. Smart Home Wireless Sensor Nodes

    DEFF Research Database (Denmark)

    Lynggaard, Per

    Smart homes are further development of intelligent buildings and home automation, where context awareness and autonomous behaviour are added. They are based on a combination of the Internet and emerging technologies like wireless sensor nodes. These wireless sensor nodes are challenging because....... This paper introduces an approach that considerably lowers the wireless sensor node power consumption and the amount of transmitted sensor events. It uses smart objects that include artificial intelligence to efficiently process the sensor event on location and thereby saves the costly wireless...

  12. Some Challenges in Wireless Security

    National Research Council Canada - National Science Library

    Banerjee, Suman

    2007-01-01

    Wireless communication technologies provide users with significant flexibility and portability and hence is being widely adopted as a preferred mode of communication in many military and civilian applications...

  13. Smart Home Wireless Sensor Nodes

    DEFF Research Database (Denmark)

    Lynggaard, Per

    . This paper introduces an approach that considerably lowers the wireless sensor node power consumption and the amount of transmitted sensor events. It uses smart objects that include artificial intelligence to efficiently process the sensor event on location and thereby saves the costly wireless......Smart homes are further development of intelligent buildings and home automation, where context awareness and autonomous behaviour are added. They are based on a combination of the Internet and emerging technologies like wireless sensor nodes. These wireless sensor nodes are challenging because...

  14. Cognitive wireless networks

    CERN Document Server

    Feng, Zhiyong; Zhang, Ping

    2015-01-01

    This brief examines the current research in cognitive wireless networks (CWNs). Along with a review of challenges in CWNs, this brief presents novel theoretical studies and architecture models for CWNs, advances in the cognitive information awareness and delivery, and intelligent resource management technologies. The brief presents the motivations and concepts of CWNs, including theoretical studies of temporal and geographic distribution entropy as well as cognitive information metrics. A new architecture model of CWNs is proposed with theoretical, functional and deployment architectures suppo

  15. The Design of Remote Control Terminal System for Three Channel Solar Telescope in Huairou in LAN

    Science.gov (United States)

    Shen, Ji; Hu, Ke-Liang; Lin, Jia-Ben; Deng, Yuan-Yong

    2008-09-01

    Using Huairou three-channel solar magnetic field telescope to carry out multi-level sun synchronous observation can obtain active image of different levels at the same time, which has an important significance in solar physics. Based on the Huairou three-channel solar magnetic field telescope the authors develop remote terminal Observing System to carry out the observation of three-channel CCD synchronously, and through this system to achieve the synergy observation between three-channel telescope and small magnetic field telescope in Huairou station. By using VC.net integrated development environment, TC/IP protocol and socket programming, carry out the control of the three CCD of three-channel solar telescope synchronously and remotely. The system can complete the remote observing by image data and camera control command transmission in the LAN environment, and greatly reduce the cost of observation, and preliminary observations have been made.

  16. Distortion-Based Slice Level Prioritization for Real-Time Video over QoS-Enabled Wireless Networks

    Directory of Open Access Journals (Sweden)

    Ismail A. Ali

    2012-01-01

    Full Text Available This paper presents a prioritization scheme based on an analysis of the impact on objective video quality when dropping individual slices from coded video streams. It is shown that giving higher-priority classified packets preference in accessing the wireless media results in considerable quality gain (up to 3 dB in tests over the case when no prioritization is applied. The proposed scheme is demonstrated for an IEEE 802.11e quality-of-service- (QoS- enabled wireless LAN. Though more complex prioritization systems are possible, the proposed scheme is crafted for mobile interactive or user-to-user video services and is simply implemented within the Main or the Baseline profiles of an H.264 codec.

  17. Green Wireless Power Transfer Networks

    NARCIS (Netherlands)

    Liu, Q.; Golinnski, M.; Pawelczak, P.; Warnier, M.

    2016-01-01

    wireless power transfer network (WPTN) aims to support devices with cable-less energy on-demand. Unfortunately, wireless power transfer itself-especially through radio frequency radiation rectification-is fairly inefficient due to decaying power with distance, antenna polarization, etc.

  18. Wireless Networks: a brief introduction

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Wireless Networks: a brief introduction. Wireless communication: What? Why? How many types? What is cell? Is it different from fixed landline structure? 1G systems: FDMA/FDD and Analog FM [voice comm]. (Introduced in 1983 in Chicago by AMPS). 2G systems: 3 ...

  19. Experiences from Implementing a Mobile Multiplayer Real-Time Game for Wireless Networks with High Latency

    Directory of Open Access Journals (Sweden)

    Alf Inge Wang

    2009-01-01

    Full Text Available This paper describes results and experiences from designing, implementing, and testing a multiplayer real-time game over mobile networks with high latency. The paper reports on network latency and bandwidth measurements from playing the game live over GPRS, EDGE, UMTS, and WLAN using the TCP and the UDP protocols. These measurements describe the practical constraints of various wireless networks and protocols when used for mobile multiplayer game purposes. Further, the paper reports on experiences from implementing various approaches to minimize issues related to high latency. Specifically, the paper focuses on a discussion about how much of the game should run locally on the client versus on the server to minimize the load on the mobile device and obtain sufficient consistency in the game. The game was designed to reveal all kinds of implementation issues of mobile network multiplayer games. The goal of the game is for a player to push other players around and into traps where they loose their lives. The game relies heavily on collision detection between the players and game objects. The paper presents experiences from experimenting with various approaches that can be used to handle such collisions, and highlights the advantages and disadvantages of the various approaches.

  20. Design of a compact tuning fork-shaped notched ultrawideband antenna for wireless communication application.

    Science.gov (United States)

    Shakib, M N; Moghavvemi, M; Mahadi, W N L

    2014-01-01

    A new compact planar notched ultrawideband (UWB) antenna is designed for wireless communication application. The proposed antenna has a compact size of 0.182λ × 0.228λ × 0.018λ where λ is the wavelength of the lowest operating frequency. The antenna is comprised of rectangular radiating patch, ground plane, and an arc-shaped strip in between radiating patch and feed line. By introducing a new Tuning Fork-shaped notch in the radiating plane, a stopband is obtained. The antenna is tested and measured. The measured result indicated that fabricated antenna has achieved a wide bandwidth of 4.33-13.8 GHz (at -10 dB return loss) with a rejection frequency band of 5.28-6.97 GHz (WiMAX, WLAN, and C-band). The effects of the parameters of the antenna are discussed. The experiment results demonstrate that the proposed antenna can well meet the requirement for the UWB communication in spite of its compactness and small size.

  1. Design of a Compact Tuning Fork-Shaped Notched Ultrawideband Antenna for Wireless Communication Application

    Directory of Open Access Journals (Sweden)

    M. N. Shakib

    2014-01-01

    Full Text Available A new compact planar notched ultrawideband (UWB antenna is designed for wireless communication application. The proposed antenna has a compact size of 0.182λ × 0.228λ × 0.018λ where λ is the wavelength of the lowest operating frequency. The antenna is comprised of rectangular radiating patch, ground plane, and an arc-shaped strip in between radiating patch and feed line. By introducing a new Tuning Fork-shaped notch in the radiating plane, a stopband is obtained. The antenna is tested and measured. The measured result indicated that fabricated antenna has achieved a wide bandwidth of 4.33–13.8 GHz (at −10 dB return loss with a rejection frequency band of 5.28–6.97 GHz (WiMAX, WLAN, and C-band. The effects of the parameters of the antenna are discussed. The experiment results demonstrate that the proposed antenna can well meet the requirement for the UWB communication in spite of its compactness and small size.

  2. Electromagnetic design methods in systems-on-chip: integrated filters for wireless CMOS RFICs

    International Nuclear Information System (INIS)

    Contopanagos, Harry

    2005-01-01

    We present general methods for designing on-chip CMOS passives and utilizing these integrated elements to design on-chip CMOS filters for wireless communications. These methods rely on full-wave electromagnetic numerical calculations that capture all the physics of the underlying foundry technologies. This is especially crucial for deep sub-micron CMOS technologies as it is important to capture the physical effects of finite (and mediocre) Q-factors limited by material losses and constraints on expensive die area, low self-resonance frequencies and dual parasitics that are particularly prevalent in deep sub-micron CMOS processes (65 nm-0.18 μm. We use these integrated elements in an ideal synthesis of a Bluetooth/WLAN pass-band filter in single-ended or differential architectures, and show the significant deviations of the on-chip filter response from the ideal one. We identify which elements in the filter circuit need to maximize their Q-factors and which Q-factors do not affect the filter performance. This saves die area, and predicts the FET parameters (especially transconductances) and negative-resistance FET topologies that have to be integrated in the filter to restore its performance. (invited paper)

  3. Informatics in Radiology (infoRAD): mobile wireless DICOM server system and PDA with high-resolution display: feasibility of group work for radiologists.

    Science.gov (United States)

    Nakata, Norio; Kandatsu, Susumu; Suzuki, Naoki; Fukuda, Kunihiko

    2005-01-01

    A novel mobile system has been developed for use by radiologists in managing Digital Imaging and Communications in Medicine (DICOM) image data. The system consists of a mobile DICOM server (MDS) and personal digital assistants (PDAs), including a Linux PDA with a video graphics array (VGA) display (307,200 pixels, 3.7 inches). The MDS weighs 410 g, has a 60-GB hard disk drive and a built-in wireless local area network (LAN) access point, and supports a DICOM server (Central Test Node). The Linux-based MDS can be accessed with personal computers (PCs) and PDAs by means of a wireless or wired LAN, and client-server communications can be established at any time. DICOM images can be displayed by using any PDA or PC by means of a Web browser. Simultaneous access to the MDS is possible for multiple authenticated users. With most PDAs, image compression is necessary for complete display of DICOM images; however, the VGA screen can display a 512 x 512-pixel DICOM image almost in its entirety. This wireless system allows efficient management of heavy loads of lossless DICOM image data and will be useful for collaborative work by radiologists in education, conferences, and research.

  4. A mobile field-work data collection system for the wireless era of health surveillance.

    Science.gov (United States)

    Forsell, Marianne; Sjögren, Petteri; Renard, Matthew; Johansson, Olle

    2011-03-01

    In many countries or regions the capacity of health care resources is below the needs of the population and new approaches for health surveillance are needed. Innovative projects, utilizing wireless communication technology, contribute to reliable methods for field-work data collection and reporting to databases. The objective was to describe a new version of a wireless IT-support system for field-work data collection and administration. The system requirements were drawn from the design objective and translated to system functions. The system architecture was based on fieldwork experiences and administrative requirements. The Smartphone devices were HTC Touch Diamond2s, while the system was based on a platform with Microsoft .NET components, and a SQL Server 2005 with Microsoft Windows Server 2003 operating system. The user interfaces were based on .NET programming, and Microsoft Windows Mobile operating system. A synchronization module enabled download of field data to the database, via a General Packet Radio Services (GPRS) to a Local Area Network (LAN) interface. The field-workers considered the here-described applications user-friendly and almost self-instructing. The office administrators considered that the back-office interface facilitated retrieval of health reports and invoice distribution. The current IT-support system facilitates short lead times from fieldwork data registration to analysis, and is suitable for various applications. The advantages of wireless technology, and paper-free data administration need to be increasingly emphasized in development programs, in order to facilitate reliable and transparent use of limited resources.

  5. Wireless Headset Communication System

    Science.gov (United States)

    Lau, Wilfred K.; Swanson, Richard; Christensen, Kurt K.

    1995-01-01

    System combines features of pagers, walkie-talkies, and cordless telephones. Wireless headset communication system uses digital modulation on spread spectrum to avoid interference among units. Consists of base station, 4 radio/antenna modules, and as many as 16 remote units with headsets. Base station serves as network controller, audio-mixing network, and interface to such outside services as computers, telephone networks, and other base stations. Developed for use at Kennedy Space Center, system also useful in industrial maintenance, emergency operations, construction, and airport operations. Also, digital capabilities exploited; by adding bar-code readers for use in taking inventories.

  6. Investigating wireless power transfer

    Science.gov (United States)

    St John, Stuart A.

    2017-09-01

    Understanding Physics is a great end in itself, but is also crucial to keep pace with developments in modern technology. Wireless power transfer, known to many only as a means to charge electric toothbrushes, will soon be commonplace in charging phones, electric cars and implanted medical devices. This article outlines how to produce and use a simple set of equipment to both demonstrate and investigate this phenomenon. It presents some initial findings and aims to encourage Physics educators and their students to conduct further research, pushing the bounds of their understanding.

  7. Dynamic wireless sensor networks

    CERN Document Server

    Oteafy, Sharief M A

    2014-01-01

    In this title, the authors leap into a novel paradigm of scalability and cost-effectiveness, on the basis of resource reuse. In a world with much abundance of wirelessly accessible devices, WSN deployments should capitalize on the resources already available in the region of deployment, and only augment it with the components required to meet new application requirements. However, if the required resources already exist in that region, WSN deployment converges to an assignment and scheduling scheme to accommodate for the new application given the existing resources. Such resources are polled

  8. Wired or Wireless Internet?

    DEFF Research Database (Denmark)

    Gimpel, Gregory

    2010-01-01

    This paper finds that network externalities play a minimal role in the choice of internet access technology. Potential adopters of mobile laptop internet view broadband technology as a black box, the technological details of which donot matter. The study uses qualitative techniques to explore how...... the speed of technological obsolescence, market share dominance, and the black boxing of technology influence consumer intention to adopt WiMax and 3G wireless internet for their laptop computers. The results, implications for industry, and areas for further research are discussed....

  9. Wireless installation standard

    International Nuclear Information System (INIS)

    Lim, Hwang Bin

    2007-12-01

    This is divided six parts which are radio regulation law on securing of radio resource, use of radio resource, protection of radio resource, radio regulation enforcement ordinance with securing, distribution and assignment of radio regulation, radio regulation enforcement regulation on utility of radio resource and technical qualification examination, a wireless installation regulation of technique standard and safety facility standard, radio regulation such as certification regulation of information communicative machines and regulation of radio station on compliance of signal security, radio equipment in radio station, standard frequency station and emergency communication.

  10. Protocol and Topology Issues for Wide-Area Satellite Interconnection of Terrestrial Optical LANs

    Science.gov (United States)

    Parraga, N.

    2002-01-01

    Apart from broadcasting, the satellite business is targeting niche markets. Wide area interconnection is considered as one of these niche markets, since it addresses operators and business LANs (B2B, business to business) in remote areas where terrestrial infrastructure is not available. These LANs - if high-speed - are typically based on optical networks such as SONET. One of the advantages of SONET is its architecture flexibility and capacity to transport all kind of applications including multimedia with a range of different transmission rates. The applications can be carried by different protocols among which the Internet Protocol (IP) or the Asynchronous Transfer Mode (ATM) are the most prominent ones. Thus, the question arises how these protocols can be interconnected via the satellite segment. The paper addresses several solutions for interworking with different protocols. For this investigation we distinguish first of all between the topology and the switching technology of the satellites. In case of a star network with transparent satellite, the satellite protocol consists of physical layer and data layer which can be directly interconnected with layer 2 interworking function to their terrestrial counterparts in the SONET backbone. For regenerative satellites the situation is more complex: here we need to distinguish the types of transport protocols being used in the terrestrial and satellite segment. Whereas IP, ATM, MPEG dominate in the terrestrial networks, satellite systems usually do not follow these standards. Some might employ minor additions (for instance, satellite specific packet headers), some might be completely proprietary. In general, interworking must be done for the data plane on top of layer 2 (data link layer), whereas for the signaling plane the interworking is on top of layer 3. In the paper we will discuss the protocol stacks for ATM, IP, and MPEG with a regenerative satellite system. As an example we will use the EuroSkyWay satellite

  11. Measurements of light at night (LAN) for a sample of female school teachers

    Science.gov (United States)

    Rea, Mark S.; Brons, Jennifer A.; Figueiro, Mariana G.

    2012-01-01

    Epidemiological studies have shown an association between rotating shiftwork and breast cancer (BC) risk. Recently, light at night (LAN) measured by satellite photometry and by self-reports of bedroom brightness has been shown to be associated with BC risk, irrespective of shiftwork history. Importance has been placed on these associations because retinal light exposures at night can suppress the hormone melatonin and/or disrupt circadian entrainment to the local 24-h light-dark cycle. The present study examined whether it was valid to use satellite photometry and self-reports of brightness to characterize light, as it might stimulate the circadian system and thereby affect BC incidence. Calibrated photometric measurements were made at the bedroom windows and in the bedrooms of a sample of female school teachers, who worked regular dayshifts and lived in a variety of satellite-measured sky brightness categories. The light levels at both locations were usually very low and were independent of the amount of satellite-measured light. Calibrated photometric measurements were also obtained at the corneas of these female school teachers together with calibrated accelerometer measurements for seven consecutive days and evenings. Based upon these personal light exposure and activity measurements, the female teachers who participated in this study did not have disrupted light-dark cycles like those associated with rotating shiftworkers who do exhibit a higher risk for BC. Rather, this sample of female school teachers had 24-h light-dark and activity-rest patterns very much like those experienced by dayshift nurses examined in an earlier study who are not at an elevated risk of BC. No relationship was found between the amount of satellite-measured light levels and the 24-h light-dark patterns these women experienced. It was concluded from the present study that satellite photometry is unrelated to personal light exposures as they might affect melatonin suppression and

  12. Household wireless electroencephalogram hat

    Science.gov (United States)

    Szu, Harold; Hsu, Charles; Moon, Gyu; Yamakawa, Takeshi; Tran, Binh

    2012-06-01

    We applied Compressive Sensing to design an affordable, convenient Brain Machine Interface (BMI) measuring the high spatial density, and real-time process of Electroencephalogram (EEG) brainwaves by a Smartphone. It is useful for therapeutic and mental health monitoring, learning disability biofeedback, handicap interfaces, and war gaming. Its spec is adequate for a biomedical laboratory, without the cables hanging over the head and tethered to a fixed computer terminal. Our improved the intrinsic signal to noise ratio (SNR) by using the non-uniform placement of the measuring electrodes to create the proximity of measurement to the source effect. We computing a spatiotemporal average the larger magnitude of EEG data centers in 0.3 second taking on tethered laboratory data, using fuzzy logic, and computing the inside brainwave sources, by Independent Component Analysis (ICA). Consequently, we can overlay them together by non-uniform electrode distribution enhancing the signal noise ratio and therefore the degree of sparseness by threshold. We overcame the conflicting requirements between a high spatial electrode density and precise temporal resolution (beyond Event Related Potential (ERP) P300 brainwave at 0.3 sec), and Smartphone wireless bottleneck of spatiotemporal throughput rate. Our main contribution in this paper is the quality and the speed of iterative compressed image recovery algorithm based on a Block Sparse Code (Baranuick et al, IEEE/IT 2008). As a result, we achieved real-time wireless dynamic measurement of EEG brainwaves, matching well with traditionally tethered high density EEG.

  13. Biomonitoring with Wireless Communications

    Energy Technology Data Exchange (ETDEWEB)

    Budinger, Thomas F.

    2003-03-01

    This review is divided into three sections: technologies for monitoring physiological parameters; biosensors for chemical assays and wireless communications technologies including image transmissions. Applications range from monitoring high risk patients for heart, respiratory activity and falls to sensing levels of physical activity in military, rescue, and sports personnel. The range of measurements include, heart rate, pulse wave form, respiratory rate, blood oxygen, tissue pCO2, exhaled carbon dioxide and physical activity. Other feasible measurements will employ miniature chemical laboratories on silicon or plastic chips. The measurements can be extended to clinical chemical assays ranging from common blood assays to protein or specialized protein measurements (e.g., troponin, creatine, and cytokines such as TNF and IL6). Though the feasibility of using wireless technology to communicate vital signs has been demonstrated 32 years ago (1) it has been only recently that practical and portable devices and communications net works have become generally available for inexpensive deployment of comfortable and affordable devices and systems.

  14. Software implementation of MPEG-II video encoding using socket programming in LAN

    Science.gov (United States)

    Yu, Yanbin; Anastassiou, Dimitris

    1994-05-01

    This contribution will examine the parallel characteristics of MPEG video encoding and explore the feasibility of using a group of workstations under a LAN to perform MPEG-II encoding. An analysis of partitioning the MPEG algorithm into several tasks is presented. This is followed by the details of implementation by using socket programming as a means to coordinate the workstations. The following conclusions have been reached: (1) Since each slice header has a start code which is byte-aligned, each slice is a good basic unit for parallel processing. This is the case for I- P- and B-pictures. (2) All the most computationally expensive operations, such as Motion Estimation and DCT, can be conducted in parallel. (3) The quantization parameter is processed in a sequential manner since it should be derived from the history of the encoding. Computer simulations have been conducted, and the bitstreams generated are the same as those of a sequential encoder and can be decoded by an MPEG-II decoder.

  15. Madencilik Ve Cevher Hazırlama İşlemlerinde Kullanılan Kimyasallar

    OpenAIRE

    BULUT, Gülay; GÖKTEPE, Ferihan

    2017-01-01

    Madencilik kimyasal maddeleringeniş olarak kullanıldığı önemli sektörlerden biridir.  İlk çağlardan günümüze, madenin ocaktançıkarılıp satışa sunulmasına kadar geçen süreçte kimyasal maddelerin kullanımısöz konusudur.  Değişik aşamalardakullanılan çeşitli kimyasallar bazen az bazen çok miktarlarda kullanılsalar daproses açısından hepsinin çok önemli rolleri vardır. Özellikle flotasyon veyaliç gibi bir yöntemle zenginleştirme işlemi yapılıyorsa kimyasal maddelerinkullanımı daha da önem kazanma...

  16. The extrinsic cell death pathway and the élan mortel.

    Science.gov (United States)

    Wallach, D; Kang, T-B; Kovalenko, A

    2008-10-01

    Early in the exploration of the chemical nature of life, it was widely believed that the molecules of living organisms, by their very nature, differ from those of inorganic material molecules and possess a vital force ('élan vital'). Similarly, early scientific thinking on the subject of cell death and its induction by cytotoxic cells of the immune system was pervaded by a sense that the molecules mediating these functions possess intrinsic deadly activity and are dedicated exclusively to death-related tasks. This impression was also reflected in the initial notions of the mode of action of intracellular proteins that signal for death. It is now gradually becoming clear, however, that proteins participating in death induction also have functions unrelated to death. Nevertheless, as exemplified by studies of the function of caspase-8 (an enzyme that signals both for activation of the extrinsic cell-death pathway and for non-death-related effects), analysis of the mechanistic basis for such heterogeneity might allow identification of distinct structural determinants in the proteins participating in death induction that do bear death specificity.

  17. Structural processing for wireless communications

    CERN Document Server

    Lu, Jianhua; Ge, Ning

    2015-01-01

    This brief presents an alternative viewpoint on processing technology for wireless communications based on recent research advances. As a lever in emerging processing technology, the structure perspective addresses the complexity and uncertainty issues found in current wireless applications. Likewise, this brief aims at providing a new prospective to the development of communication technology and information science, while stimulating new theories and technologies for wireless systems with ever-increasing complexity. Readers of this brief may range from graduate students to researchers in related fields.

  18. Radio Relays Improve Wireless Products

    Science.gov (United States)

    2009-01-01

    Signal Hill, California-based XCOM Wireless Inc. developed radio frequency micromachine (RF MEMS) relays with a Phase II Small Business Innovation Research (SBIR) contract through NASA?s Jet Propulsion Laboratory. In order to improve satellite communication systems, XCOM produced wireless RF MEMS relays and tunable capacitors that use metal-to-metal contact and have the potential to outperform most semiconductor technologies while using less power. These relays are used in high-frequency test equipment and instrumentation, where increased speed can mean significant cost savings. Applications now also include mainstream wireless applications and greatly improved tactical radios.

  19. Wireless Communications in Smart Grid

    Science.gov (United States)

    Bojkovic, Zoran; Bakmaz, Bojan

    Communication networks play a crucial role in smart grid, as the intelligence of this complex system is built based on information exchange across the power grid. Wireless communications and networking are among the most economical ways to build the essential part of the scalable communication infrastructure for smart grid. In particular, wireless networks will be deployed widely in the smart grid for automatic meter reading, remote system and customer site monitoring, as well as equipment fault diagnosing. With an increasing interest from both the academic and industrial communities, this chapter systematically investigates recent advances in wireless communication technology for the smart grid.

  20. Wireless home networking for dummies

    CERN Document Server

    Briere, Danny; Ferris, Edward

    2010-01-01

    The perennial bestseller shows you how share your files and Internet connection across a wireless network. Fully updated for Windows 7 and Mac OS X Snow Leopard, this new edition of this bestseller returns with all the latest in wireless standards and security. This fun and friendly guide shows you how to integrate your iPhone, iPod touch, smartphone, or gaming system into your home network. Veteran authors escort you through the various financial and logisitical considerations that you need to take into account before building a wireless network at home.: Covers the basics of planning, instal

  1. Microwave materials for wireless applications

    CERN Document Server

    Cruickshank, David B

    2011-01-01

    This practical resource offers you an in-depth, up-to-date understanding of the use of microwave magnetic materials for cutting-edge wireless applications. The book discusses device applications used in wireless infrastructure base stations, point-to-point radio links, and a range of more specialized microwave systems. You find detailed discussions on the attributes of each family of magnetic materials with respect to specific wireless applications. Moreover, the book addresses two of the hottest topics in the field today - insertion loss and intermodulation. This comprehensive reference also

  2. Wireless device monitoring methods, wireless device monitoring systems, and articles of manufacture

    Science.gov (United States)

    McCown, Steven H [Rigby, ID; Derr, Kurt W [Idaho Falls, ID; Rohde, Kenneth W [Idaho Falls, ID

    2012-05-08

    Wireless device monitoring methods, wireless device monitoring systems, and articles of manufacture are described. According to one embodiment, a wireless device monitoring method includes accessing device configuration information of a wireless device present at a secure area, wherein the device configuration information comprises information regarding a configuration of the wireless device, accessing stored information corresponding to the wireless device, wherein the stored information comprises information regarding the configuration of the wireless device, comparing the device configuration information with the stored information, and indicating the wireless device as one of authorized and unauthorized for presence at the secure area using the comparing.

  3. Entre games e folgações: apontamentos de uma antropóloga na lan house Between games and folgações: Anthropological notes in the lan house

    Directory of Open Access Journals (Sweden)

    Vanessa Andrade Pereira

    2007-11-01

    Full Text Available O objetivo deste artigo é apresentar o processo de aproximação da pesquisadora junto a jovens de uma lan house da cidade de Porto Alegre, RS, Brasil. Visa descrever as características dessa casa de jogo em rede, sua localização no bairro, e o cotidiano dos jovens que a usam para jogar games pela Internet ou apenas como point de sociabilidade. Demonstra como os jovens configuram seus pertencimentos e intensificam seus laços sociais através das "folgações" (jocosidade, e das interações online no game Tibia.This article wants to describe the interaction process of the anthropologist with teenagers in a lan house in Porto Alegre, Rio Grande do Sul, Brazil. First, the study will point out the peculiarities of the lan house, its location in the neighbourhood, as well as the everyday life of the young people who use this space for online playing or just for sociability. Secondly, it will discuss as youth people establish their sense of belonging and strengthen their social bounds through the folgações (joking relationships and their online interactions in the MMORPG Tibia game.

  4. Games and social Nnetworks in popular lan house: a look on anthropology uses in collective and sociability "local club"

    Directory of Open Access Journals (Sweden)

    Carla Barros

    2009-03-01

    Full Text Available This article aims to discuss some aspects of the appropriations of computer technology in the universe of urban classes, focusing on the environment of lan houses and sailing in social networks and games. The study has the principal orientation of the anthropological approach to consumption, using a methodology of ethnographic inspiration. " Even when they do not have computers at home, the young people surveyed showed a great familiarity with certain aspects of digital life, due to high frequency in the lan houses. The survey results show that ownership of these spaces as a sort of local club, as well as practice of navigation collective - are "collective machinery, working in a collaborative world, where many users are on a same computer, interacting during navigation - the importance of strengthening the social ties existing practices related to virtual networks of relationships.

  5. El Lanús : Memoria, política y psicoanálisis en la Argentina (1956-1992)

    NARCIS (Netherlands)

    Visacovsky, S.E.

    2001-01-01

    En este trabajo son estudiados los procesos de construcción de la memoria social en la Argentina, y las relaciones entre memorias políticas y memorias profesionales. El objeto empírico son los relatos sobre el pasado del más célebre servicio de salud mental de la Argentina, conocido como el Lanús

  6. Maximizing the utilization and impact of medical educational software by designing for local area network (LAN) implementation.

    OpenAIRE

    Stevens, R.; Reber, E.

    1993-01-01

    The design, development and implementation of medical education software often occurs without sufficient consideration of the potential benefits that can be realized by making the software network aware. These benefits can be considerable and can greatly enhance the utilization and potential impact of the software. This article details how multiple aspects of the IMMEX problem solving project have benefited from taking maximum advantage of LAN resources.

  7. Advanced Wireless Integrated Navy Network

    National Research Council Canada - National Science Library

    Stutzman, Warren; Habayeb, Rick

    2005-01-01

    Quarterly progress report No. I on AWINN hardware and software configurations of smart, wideband, multi-function antennas, secure configurable platform, close-in command and control for Sea Basing visualization of wireless...

  8. Wireless Damage Location Sensing System

    Science.gov (United States)

    Woodard, Stanley E. (Inventor); Taylor, Bryant Douglas (Inventor)

    2012-01-01

    A wireless damage location sensing system uses a geometric-patterned wireless sensor that resonates in the presence of a time-varying magnetic field to generate a harmonic response that will experience a change when the sensor experiences a change in its geometric pattern. The sensing system also includes a magnetic field response recorder for wirelessly transmitting the time-varying magnetic field and for wirelessly detecting the harmonic response. The sensing system compares the actual harmonic response to a plurality of predetermined harmonic responses. Each predetermined harmonic response is associated with a severing of the sensor at a corresponding known location thereof so that a match between the actual harmonic response and one of the predetermined harmonic responses defines the known location of the severing that is associated therewith.

  9. Introduction to wireless sensor networks

    CERN Document Server

    Forster, Anna

    2016-01-01

    Explores real-world wireless sensor network development, deployment, and applications. The book begins with an introduction to wireless sensor networks and their fundamental concepts. Hardware components, operating systems, protocols, and algorithms that make up the anatomy of a sensor node are described in chapter two. Properties of wireless communications, medium access protocols, wireless links, and link estimation protocols are described in chapter three and chapter four. Routing basics and metrics, clustering techniques, time synchronization and localization protocols, as well as sensing techniques are introduced in chapter five to nine. The concluding chapter summarizes the learnt methods and shows how to use them to deploy real-world sensor networks in a structured way.

  10. Wireless cortical implantable systems

    CERN Document Server

    Majidzadeh Bafar, Vahid

    2013-01-01

    Wireless Cortical Implantable Systems examines the design for data acquisition and transmission in cortical implants. The first part of the book covers existing system-level cortical implants, as well as future devices. The authors discuss the major constraints in terms of microelectronic integration. The second part of the book focuses on system-level as well as circuit and system level solutions to the development of ultra low-power and low-noise microelectronics for cortical implants. Existing solutions are presented and novel methods and solutions proposed. The third part of the book focuses on the usage of digital impulse radio ultra wide-band transmission as an efficient method to transmit cortically neural recorded data at high data-rate to the outside world. Original architectural and circuit and system solutions are discussed.

  11. Wireless Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Hong-Chuan Yang

    2007-01-01

    Full Text Available We study the energy-efficient configuration of multihop paths with automatic repeat request (ARQ mechanism in wireless ad hoc networks. We adopt a cross-layer design approach and take both the quality of each radio hop and the battery capacity of each transmitting node into consideration. Under certain constraints on the maximum tolerable transmission delay and the required packet delivery ratio, we solve optimization problems to jointly schedule the transmitting power of each transmitting node and the retransmission limit over each hop. Numerical results demonstrate that the path configuration methods can either significantly reduce the average energy consumption per packet delivery or considerably extend the average lifetime of the multihop route.

  12. Wireless Josephson amplifier

    International Nuclear Information System (INIS)

    Narla, A.; Sliwa, K. M.; Hatridge, M.; Shankar, S.; Frunzio, L.; Schoelkopf, R. J.; Devoret, M. H.

    2014-01-01

    Josephson junction parametric amplifiers are playing a crucial role in the readout chain in superconducting quantum information experiments. However, their integration with current 3D cavity implementations poses the problem of transitioning between waveguide, coax cables, and planar circuits. Moreover, Josephson amplifiers require auxiliary microwave components, like directional couplers and/or hybrids, that are sources of spurious losses and impedance mismatches that limit measurement efficiency and amplifier tunability. We have developed a wireless architecture for these parametric amplifiers that eliminates superfluous microwave components and interconnects. This greatly simplifies their assembly and integration into experiments. We present an experimental realization of such a device operating in the 9–11 GHz band with about 100 MHz of amplitude gain-bandwidth product, on par with devices mounted in conventional sample holders. The simpler impedance environment presented to the amplifier also results in increased amplifier tunability.

  13. Secure positioning in wireless networks

    DEFF Research Database (Denmark)

    Capkun, Srdjan; Hubaux, Jean-Pierre

    2006-01-01

    So far, the problem of positioning in wireless networks has been studied mainly in a non-adversarial settings. In this work, we analyze the resistance of positioning techniques to position and distance spoofing attacks. We propose a mechanism for secure positioning of wireless devices, that we call...... Verifiable Multilateration. We then show how this mechanism can be used to secure positioning in sensor networks. We analyze our system through simulations....

  14. Wireless Communications in Reverberant Environments

    Science.gov (United States)

    2015-01-01

    solutions exist which can be tailored to meet the needs nearly any wireless application. Some notable current solutions include USRPs [27] and GNURadio ...tailored to meet the needs nearly any wireless application. Some notable current solutions include USRPs [27] and GNURadio [28]. For this effort, the WARPv3...en.wikipedia.org/wiki/List of software-defined radios [27] “Ettus research.” [Online]. Available: http://www.ettus.com [28] “ Gnuradio .” [Online]. Available: http

  15. WIRELESS MINE WIDE TELECOMMUNICATIONS TECHNOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Zvi H. Meiksin

    2002-04-01

    Two industrial prototype units for through-the-earth wireless communication were constructed and tested. Preparation for a temporary installation in NIOSH's Lake Lynn mine for the through-the-earth and the in-mine system were completed. Progress was made in the programming of the in-mine system to provide data communication. Work has begun to implement a wireless interface between equipment controllers and our in-mine system.

  16. WIRELESS MINE WIDE TELECOMMUNICATIONS TECHNOLOGY

    International Nuclear Information System (INIS)

    Zvi H. Meiksin

    2002-01-01

    Two industrial prototype units for through-the-earth wireless communication were constructed and tested. Preparation for a temporary installation in NIOSH's Lake Lynn mine for the through-the-earth and the in-mine system were completed. Progress was made in the programming of the in-mine system to provide data communication. Work has begun to implement a wireless interface between equipment controllers and our in-mine system

  17. Spent Mushroom Waste as a Media Replacement for Peat Moss in Kai-Lan (Brassica oleracea var. Alboglabra Production

    Directory of Open Access Journals (Sweden)

    H. Sendi

    2013-01-01

    Full Text Available Peat moss (PM is the most widely used growing substrate for the pot culture. Due to diminishing availability and increasing price of PM, researchers are looking for viable alternatives for peat as a growth media component for potted plants. A pot study was conducted with a view to investigate the possibility of using spent mushroom waste (SMW for Kai-lan (Brassica oleracea var. Alboglabra production replacing peat moss (PM in growth media. The treatments evaluated were 100% PM (control, 100% SMW, and mixtures of SMW and PM in different ratios like 1 : 1, 1 : 2, and 2 : 1 (v/v with/without NPK amendment. The experiment was arranged in a completely randomized design with five replications per treatment. Chemical properties like pH and salinity level (EC of SMW were within the acceptable range of crop production but, nutrient content, especially nitrogen content was not enough to provide sufficient nutrition to plant for normal growth. Only PM (100% and SMW and PM mixture in 1 : 1 ratio with NPK amendment performed equally in terms of Kai-lan growth. This study confirms the feasibility of replacing PM by SMW up to a maximum of 50% in the growth media and suggests that NPK supplementation from inorganic sources is to ensure a higher productivity of Kai-lan.

  18. Spent mushroom waste as a media replacement for peat moss in Kai-Lan (Brassica oleracea var. Alboglabra) production.

    Science.gov (United States)

    Sendi, H; Mohamed, M T M; Anwar, M P; Saud, H M

    2013-01-01

    Peat moss (PM) is the most widely used growing substrate for the pot culture. Due to diminishing availability and increasing price of PM, researchers are looking for viable alternatives for peat as a growth media component for potted plants. A pot study was conducted with a view to investigate the possibility of using spent mushroom waste (SMW) for Kai-lan (Brassica oleracea var. Alboglabra) production replacing peat moss (PM) in growth media. The treatments evaluated were 100% PM (control), 100% SMW, and mixtures of SMW and PM in different ratios like 1 : 1, 1 : 2, and 2 : 1 (v/v) with/without NPK amendment. The experiment was arranged in a completely randomized design with five replications per treatment. Chemical properties like pH and salinity level (EC) of SMW were within the acceptable range of crop production but, nutrient content, especially nitrogen content was not enough to provide sufficient nutrition to plant for normal growth. Only PM (100%) and SMW and PM mixture in 1 : 1 ratio with NPK amendment performed equally in terms of Kai-lan growth. This study confirms the feasibility of replacing PM by SMW up to a maximum of 50% in the growth media and suggests that NPK supplementation from inorganic sources is to ensure a higher productivity of Kai-lan.

  19. Coexistence of IEEE 802.11b/g WLANs and IEEE 802.15.4 WSNs : Modeling and Protocol Enhancements

    NARCIS (Netherlands)

    Yuan, W.

    2011-01-01

    As an emerging short-range wireless technology, IEEE 802.15.4/ZigBee Wireless Sensor Networks (WSNs) are increasingly used in the fields of home control, industrial control, consumer electronics, energy management, building automation, telecom services, personal healthcare, etc. IEEE

  20. Coupled geohazards at Southern Andes (Copahue-Lanín volcanoes): Chile's GEO supersite proposal

    Science.gov (United States)

    Lara, Luis E.; Cordova, Loreto

    2017-04-01

    Southern Andes are a young and active mountain belt where volcanism and tectonic processes (and those related to the hydrometeorological conditions controlled by this geological setting) pose a significant threat to the growing communities nearby. This proposal focus on a ca. 200 km long segment of the Southern Andes where 9 stratovolcanoes and 2 distributed volcanic fields are located, just along a tectonic corridor defined by the northern segment of the Liquiñe-Ofqui Faul System (LOFS), a long-lived active strike-slip fault running for 1200 km. Volcanoes in this area take part of the central province of the Andean Southern Volcanic Zone (37-41°S), particularly the northermost portion that is limited at the south by an Andean tranverse fault (Lanalhue Fault, which define the Villarrica-Lanin volcanic chain) and run along the horse-tail array of the LOFS to the north. Most of the stravolcanoes are atop of the LOFS main branch with only 3 exceptions (Callaqui, Tolhuaca and Lanín) 15-20 km away, but related to transverse faults. Hazards in the segment derive from the activity of some of the most active volcanoes in South America (e.g., Villarrica, Llaima), others with long-lasting weak activity (e.g., Copahue) or some volcanoes with low frequency but high magnitude eruptions in the geological record. Only since the beggining of the 20th century 80 eruptions have been recorded in this area. In addition, activity of the LOFS has been detected prior to some eruptions and coeval with some others (e.g., Lonquimay 1989). A strong two-way coupling between tectonics and volcanism has been proposed for the segment but only recently detected by geophysical techniques or numerical modelling. Tectonic triggered landslides are frequent in this region together with debris flows at erupting ice-covered volcanoes or stream headed at high altitude basins. The latter scenario seems to be worst at present because of global climate change. Ground-based monitoring networks for both

  1. Virtual Private Lan Services Over IP/MPLS Networks and Router Configurations

    Directory of Open Access Journals (Sweden)

    Pınar KIRCI

    2015-06-01

    Full Text Available The rising number of users and ever growing traffic rates over the networks reveal the need of higher bandwidth and transmission rates. At every packet transmission process, routers need to route the packets by looking at the routing tables, this fact leads to an increase at the load of the routers and at the amount of time consumed during the processes. Today, users need high level security, faster data transmission and easy managed network structures because of the increasing technology usage. MPLS network structures can provide these requirements with their QoS feature. In our work, at first a topology structure is constructed with the routers that are used in Alcatel-Lucent laboratories. OSPF (Open Shortest Path First routing protocol and MPLS (Multiprotocol Label Switching technologies are used over the topology. Afterwards, E-pipe (Ethernet Pipe and VPLS (Virtual private LAN services configurations are performed over the routers. To illustrate the current network data traffic, three tests are performed in the study. Routers’ configurations are performed by Secure-CRT and still developing i-Gen software. With i-Gen, many routers’ configurations can be performed with a user friendly interface. Instead of performing the configurations one by one with Secure CRT, the user can perform the routers’ configurations easily by entering the needed values for the system with i-Gen software. So, with the new and developing i-Gen software, the users’ workload is minimized and streamlined. In our work, Secure-CRT software which is mostly preferred for router configurations at Windows operating system and i-Gen software which is developed by Alcatel-Lucent are considered. Both of the router configuration softwares are worked on and gained results are expounded. Consequently, instead of using time consuming Secure-CRT software, with utilizing new developed i-Gen software, the users’ work load is minimized.

  2. Hybrid Indoor-Based WLAN-WSN Localization Scheme for Improving Accuracy Based on Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Zahid Farid

    2016-01-01

    Full Text Available In indoor environments, WiFi (RSS based localization is sensitive to various indoor fading effects and noise during transmission, which are the main causes of localization errors that affect its accuracy. Keeping in view those fading effects, positioning systems based on a single technology are ineffective in performing accurate localization. For this reason, the trend is toward the use of hybrid positioning systems (combination of two or more wireless technologies in indoor/outdoor localization scenarios for getting better position accuracy. This paper presents a hybrid technique to implement indoor localization that adopts fingerprinting approaches in both WiFi and Wireless Sensor Networks (WSNs. This model exploits machine learning, in particular Artificial Natural Network (ANN techniques, for position calculation. The experimental results show that the proposed hybrid system improved the accuracy, reducing the average distance error to 1.05 m by using ANN. Applying Genetic Algorithm (GA based optimization technique did not incur any further improvement to the accuracy. Compared to the performance of GA optimization, the nonoptimized ANN performed better in terms of accuracy, precision, stability, and computational time. The above results show that the proposed hybrid technique is promising for achieving better accuracy in real-world positioning applications.

  3. Traffic Profiling in Wireless Sensor Networks

    National Research Council Canada - National Science Library

    Kirykos, Georgios

    2006-01-01

    .... Wireless sensor networks pose unique challenges and limitations to the traditional schemes, which are used in the other wireless networks for security protection, and are due mainly to the increased...

  4. CMOS circuits for passive wireless microsystems

    CERN Document Server

    Yuan, Fei

    2011-01-01

    Here is a comprehensive examination of CMOS circuits for passive wireless microsystems. Covers design challenges, fundamental issues of ultra-low power wireless communications, radio-frequency power harvesting, and advanced design techniques, and more.

  5. Wireless Sensor Portal Technology, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Mobitrum Corporation has demonstrated the feasibility in the Phase I of " A Wireless Sensor Portal Technology" and proposes a Phase II effort to develop a wireless...

  6. Kali Linux wireless penetration testing beginner's guide

    CERN Document Server

    Ramachandran, Vivek

    2015-01-01

    If you are a security professional, pentester, or anyone interested in getting to grips with wireless penetration testing, this is the book for you. Some familiarity with Kali Linux and wireless concepts is beneficial.

  7. STUDY & SURVEY ON WIRELESS CHARGING & TECHNOLOGY

    OpenAIRE

    Harshal Sharma*

    2016-01-01

    In the modern world, we have often heard a word- wireless charging technology. Actually what is it all about? So this paper is giving you the whole package about wireless charging technology. Wireless charging is a technology through which power is transmitted through an air gap to the electrical devices for the motive of replenishment of energy. At present wireless charging techniques and development of commercial products have provided a promise to address the energy bottleneck of portable ...

  8. Security Threats on Wireless Sensor Network Protocols

    OpenAIRE

    H. Gorine; M. Ramadan Elmezughi

    2016-01-01

    In this paper, we investigate security issues and challenges facing researchers in wireless sensor networks and countermeasures to resolve them. The broadcast nature of wireless communication makes Wireless Sensor Networks prone to various attacks. Due to resources limitation constraint in terms of limited energy, computation power and memory, security in wireless sensor networks creates different challenges than wired network security. We will discuss several attempts at addressing the issue...

  9. Techniques for Wireless Applications

    KAUST Repository

    Gaaloul, Fakhreddine

    2012-05-01

    Switching techniques have been first proposed as a spacial diversity techniques. These techniques have been shown to reduce considerably the processing load while letting multi-antenna systems achieve a specific target performance. In this thesis, we take a different look at the switching schemes by implementing them for different other wireless applications. More specifically, this thesis consists of three main parts, where the first part considers a multiuser environment and an adaptive scheduling algorithm based on the switching with post-selection scheme for statistically independent but non-identically distributed channel conditions. The performance of this switched based scheduler is investigated and a multitude of performance metrics are presented. In a second part, we propose and analyze the performance of three switched-based algorithms for interference reduction in the downlink of over-loaded femtocells. For instance, performance metrics are derived in closed-form and these metrics are used to compare these three proposed schemes. Finally in a third part, a switch based opportunistic channel access scheme is proposed for a cognitive radio system and its performance is analyzed in terms of two new proposed metrics namely the average cognitive radio access and the waiting time duration.

  10. Wireless capsule endo bronchoscopy

    Directory of Open Access Journals (Sweden)

    Baratz DM

    2014-03-01

    Full Text Available No abstract available. Article truncated at 150 words. Case Presentation History of Present Illness A 67 year-old man presents 10 days after swallowing a capsule endoscopy camera that was never retrieved. The wireless capsule was swallowed asymptomatically for evaluation of heme positive stools after negative upper and lower endoscopies. Patient noted that the evening after swallowing the camera he developed mild shortness of breath and cough. The cough and shortness of breath were persistent and worsened while lying down and when moving positions. He denied prior issues with swallowing or aspiration. Review of Systems Negative other than what is noted above. PMH, SH, and FH Past medical history: coronary artery disease, peripheral vascular disease, hyperlipidemia Surgical history: femoral-popliteal bypass, previous shoulder and back surgery Social history: 1 pack/day of cigarettes for 50 years, prior alcohol usage but not current, no illicit drugs Family history: no pulmonary diseases Physical Exam Vital signs: temperature 36.7º C, heart rate 86 beats per minute ...

  11. Advanced Wireless Sensor Nodes - MSFC

    Science.gov (United States)

    Varnavas, Kosta; Richeson, Jeff

    2017-01-01

    NASA field center Marshall Space Flight Center (Huntsville, AL), has invested in advanced wireless sensor technology development. Developments for a wireless microcontroller back-end were primarily focused on the commercial Synapse Wireless family of devices. These devices have many useful features for NASA applications, good characteristics and the ability to be programmed Over-The-Air (OTA). The effort has focused on two widely used sensor types, mechanical strain gauges and thermal sensors. Mechanical strain gauges are used extensively in NASA structural testing and even on vehicle instrumentation systems. Additionally, thermal monitoring with many types of sensors is extensively used. These thermal sensors include thermocouples of all types, resistive temperature devices (RTDs), diodes and other thermal sensor types. The wireless thermal board will accommodate all of these types of sensor inputs to an analog front end. The analog front end on each of the sensors interfaces to the Synapse wireless microcontroller, based on the Atmel Atmega128 device. Once the analog sensor output data is digitized by the onboard analog to digital converter (A/D), the data is available for analysis, computation or transmission. Various hardware features allow custom embedded software to manage battery power to enhance battery life. This technology development fits nicely into using numerous additional sensor front ends, including some of the low-cost printed circuit board capacitive moisture content sensors currently being developed at Auburn University.

  12. WIRELESS FIDELITY (Wi-Fi) BROADBAND NETWORK ...

    African Journals Online (AJOL)

    ES Obe

    categorized into two types: fixed and mobile wireless. The broadband fixed wireless network technologies .... 3.0 WIRELESS FIDELITYF (Wi-Fi). NETWORK IMPLEMENTATION. A Wi-Fi enabled device such as a PC, game .... Amateur radio, video senders, and cordless phones, can cause significant additional interference.

  13. WirelessHART modeling and performance evaluation

    NARCIS (Netherlands)

    Remke, Anne Katharina Ingrid; Wu, Xian

    2013-01-01

    In process industries wired supervisory and control networks are more and more replaced by wireless systems. Wireless communication inevitably introduces time delays and message losses, which may degrade the system reliability and performance. WirelessHART, as the first international standard for

  14. Wireless device monitoring systems and monitoring devices, and associated methods

    Science.gov (United States)

    McCown, Steven H; Derr, Kurt W; Rohde, Kenneth W

    2014-05-27

    Wireless device monitoring systems and monitoring devices include a communications module for receiving wireless communications of a wireless device. Processing circuitry is coupled with the communications module and configured to process the wireless communications to determine whether the wireless device is authorized or unauthorized to be present at the monitored area based on identification information of the wireless device. Methods of monitoring for the presence and identity of wireless devices are also provided.

  15. Impact of wireless link quality across communication layers

    OpenAIRE

    Zhou, J.

    2010-01-01

    Nowadays, wireless networks are used in most of the applications with radio technologies being used in all kinds of wireless networks. In all wireless links, the transmitted packets can be lost. How to identify the quality of a certain wireless link and achieve the best delivery performance over a certain wireless network is an open issue. In this thesis, the performance of wireless mesh network, wireless sensor network and cellular network have been investigated by the method of measurements...

  16. Distinção e Compartilhamento no Jogo da Sociabilidade Juvenil: Um Estudo em Lan House Popular

    Directory of Open Access Journals (Sweden)

    Carla Barros

    2011-07-01

    Full Text Available O artigo tem como objetivo investigar apropriações de tecnologias digitais e vivências de sociabilidade junto a um grupo pertencente às camadas populares, através de um trabalho de campo etnográfico realizado em lan houses. O foco do artigo recai sobre questões como: os significados das navegações no universo dos games e a apropriação de tecnologias digitais como um modo de engendrar identidades e classificações, através dos caminhos da distinção social e dos “gostos” culturais.

  17. Wireless Augmented Reality Communication System

    Science.gov (United States)

    Devereaux, Ann (Inventor); Jedrey, Thomas (Inventor); Agan, Martin (Inventor)

    2017-01-01

    A portable unit is for video communication to select a user name in a user name network. A transceiver wirelessly accesses a communication network through a wireless connection to a general purpose node coupled to the communication network. A user interface can receive user input to log on to a user name network through the communication network. The user name network has a plurality of user names, at least one of the plurality of user names is associated with a remote portable unit, logged on to the user name network and available for video communication.

  18. OFDM systems for wireless communications

    CERN Document Server

    Narasimhamurthy, Adarsh

    2010-01-01

    Orthogonal Frequency Division Multiplexing (OFDM) systems are widely used in the standards for digital audio/video broadcasting, WiFi and WiMax. Being a frequency-domain approach to communications, OFDM has important advantages in dealing with the frequency-selective nature of high data rate wireless communication channels. As the needs for operating with higher data rates become more pressing, OFDM systems have emerged as an effective physical-layer solution.This short monograph is intended as a tutorial which highlights the deleterious aspects of the wireless channel and presents why OFDM is

  19. Embracing interference in wireless systems

    CERN Document Server

    Gollakota, Shyamnath

    2014-01-01

    The wireless medium is a shared resource. If nearby devices transmit at thesame time, their signals interfere, resulting in a collision. In traditionalnetworks, collisions cause the loss of the transmitted information. For thisreason, wireless networks have been designed with the assumption thatinterference is intrinsically harmful and must be avoided.This book, a revised version of the author's award-winning Ph.D.dissertation, takes an alternate approach: Instead of viewing interferenceas an inherently counterproductive phenomenon that should to be avoided, wedesign practical systems that tra

  20. The Wireless Nursing Call System

    DEFF Research Database (Denmark)

    Jensen, Casper Bruun

    2006-01-01

    This paper discusses a research project in which social scientists were involved both as analysts and supporters during a pilot with a new wireless nursing call system. The case thus exemplifies an attempt to participate in developing dependable health care systems and offers insight into the cha......This paper discusses a research project in which social scientists were involved both as analysts and supporters during a pilot with a new wireless nursing call system. The case thus exemplifies an attempt to participate in developing dependable health care systems and offers insight...

  1. Artificial intelligence in wireless communications

    CERN Document Server

    Rondeau, Thomas W

    2009-01-01

    This cutting-edge resource offers practical overview of cognitive radio, a paradigm for wireless communications in which a network or a wireless node changes its transmission or reception parameters. The alteration of parameters is based on the active monitoring of several factors in the external and internal radio environment. This book offers a detailed description of cognitive radio and its individual parts. Practitioners learn how the basic processing elements and their capabilities are implemented as modular components. Moreover, the book explains how each component can be developed and t

  2. Emerging wireless networks concepts, techniques and applications

    CERN Document Server

    Makaya, Christian

    2011-01-01

    An authoritative collection of research papers and surveys, Emerging Wireless Networks: Concepts, Techniques, and Applications explores recent developments in next-generation wireless networks (NGWNs) and mobile broadband networks technologies, including 4G (LTE, WiMAX), 3G (UMTS, HSPA), WiFi, mobile ad hoc networks, mesh networks, and wireless sensor networks. Focusing on improving the performance of wireless networks and provisioning better quality of service and quality of experience for users, it reports on the standards of different emerging wireless networks, applications, and service fr

  3. Principles of wireless access and localization

    CERN Document Server

    Pahlavan, Kaveh

    2013-01-01

    A comprehensive, encompassing and accessible text examining a wide range of key Wireless Networking and Localization technologies This book provides a unified treatment of issues related to all wireless access and wireless localization techniques.  The book reflects principles of design and deployment of infrastructure for wireless access and localization for wide, local, and personal networking.   Description of wireless access methods includes design and deployment of traditional TDMA and CDMA technologies and emerging Long Term Evolution (LTE) techniques for wide area cellular networks, the

  4. Efficient Wireless Charger Deployment for Wireless Rechargeable Sensor Networks

    Directory of Open Access Journals (Sweden)

    Jehn-Ruey Jiang

    2016-08-01

    Full Text Available A wireless rechargeable sensor network (WRSN consists of sensor nodes that can harvest energy emitted from wireless chargers for refilling their batteries so that the WRSN can operate sustainably. This paper assumes wireless chargers are equipped with directional antennas, and are deployed on grid points of a fixed height to propose two heuristic algorithms solving the following wireless charger deployment optimization (WCDO problem: how to deploy as few as possible chargers to make the WRSN sustainable. Both algorithms model the charging space of chargers as a cone and calculate charging efficiency according power regression expressions complying with the Friis transmission equation. The two algorithms are the greedy cone covering (GCC algorithm and the adaptive cone covering (ACC algorithm. The GCC (respectively, ACC algorithm greedily (respectively, adaptively generates candidate cones to cover as many as possible sensor nodes. Both algorithms then greedily select the fewest number of candidate cones, each of which corresponds to the deployment of a charger, to have approximate solutions to the WCDO problem. We perform experiments, conduct simulations and do analyses for the algorithms to compare them in terms of the time complexity, the number of chargers deployed, and the execution time.

  5. Wireless Ways: Business and Personal Applications of Wireless Technology.

    Science.gov (United States)

    Chung, Joe

    2001-01-01

    Describes the Art Technology Group (ATG), an electronic business and customer management company, and the work they have done with wireless technology. Highlights include designing virtual offices and supporting the resulting virtual community; the mobility it allows; problems with bandwidth; and display issues. (LRW)

  6. Introduction to Ultra Wideband for Wireless Communications

    DEFF Research Database (Denmark)

    Nikookar, Homayoun; Prasad, Ramjee

    Ultra Wideband (UWB) Technology is the cutting edge technology for wireless communications with a wide range of applications. In Introduction to Ultra Wideband for Wireless Communications UWB principles and technologies for wireless communications are explained clearly. Key issues such as UWB...... wireless channels, interference, signal processing as well as applications and standardization activities are addressed. Introduction to Ultra Wideband for Wireless Communications provides easy-to-understand material to (graduate) students and researchers working in the field of commercial UWB wireless...... communications. Due to tutorial nature of the book it can also be adopted as a textbook on the subject in the Telecommunications Engineering curriculum. Problems at the end of each chapter extend the reader's understanding of the subject. Introduction to Ultra Wideband for Wireless Communications will aslo...

  7. Denizli İlinde İhracatı Yapılan Mantarlar

    Directory of Open Access Journals (Sweden)

    Kutret GEZER

    2016-01-01

    Full Text Available Mantarlar protein, karbonhidrat, vitamin ve mineral gibi besinler yönünden zengin içeriğe sahip olmalarının yanı sıra farklı lezzetleriyle, yüzyıllardır insanoğlu için iyi bir besin kaynağı olmuştur. Ayrıca içerdikleri pek çok aktif bileşenin teröpatik etkilerinin bulunması besinsel değerlerini de arttırmaktadır. Ancak taze mantarların raf ömrünün kısa olması, kolay bozulmaları ve her dönemde bulunamamaları gibi bazı olumsuzluklar mantarların gıda sektöründe kullanım alanlarını sınırlamaktadır. Taze tüketime alternatif yöntemlerden biri olan kurutulmuş mantarların kullanımı dünya genelinde giderek yaygınlaşmaktadır. Mantarlar kurutulduğunda tat ve diğer özelliklerini büyük oranda korumaktadırlar. Kurutulmuş mantarlar, öğütülerek toz halinde veya bütün olarak doğrudan tüketilebildiği gibi tatlı, baharat, garnitür, mama, pizza ve çorbalara katılarak çeşitli şekillerde de tüketilebilmektedir. Ülkemizde 2007 yılında 21 ton kurutulmuş mantar ihracatı gerçekleşmiş ve 1.71 milyon dolar ülke ekonomisine katkı sağlanmıştır. Denizli ili kuru veya şoklanmış mantar ihracatında önemli bir yere sahiptir. Bu çalışmada Denizli ilinde kurutularak ihracatı yapılan Boletus edulis, Morchella esculenta, Cantharellus cibarius ve Craterellus cornucopioides türlerinin genel özellikleri ve besin içerikleriyle ilgili bilgilerin verilmesi amaçlanmıştır. Araştırma için konuyla ilgili son zamanlarda yapılmış çalışmalara ulaşılarak yazın taraması yapılmıştır. Bu çalışmaya konu olan mantar türleriyle ilgili bulgular arasındaki ilişkiler göz önüne alınarak, elde edilen veriler bir araya getirilmiş ve yorumlanmıştır.

  8. A novel wireless modulation technique for inter-standard communications

    NARCIS (Netherlands)

    Bekkaoui, A.; Haartsen, J.C.

    2006-01-01

    A new technique is presented with permits transceivers of different radio standards to communicate with each other. Applications are found in unlicensed bands where radios using different technologies, like for example Bluetooth, ZigBee, or WLAN IEEE 802.11, have to share the same radio spectrum. If

  9. A tutorial survey of topics in wireless networking: Part II

    Indian Academy of Sciences (India)

    Kumar A, Kumar V 2005 Optimal association of stations and APs in an IEEE 802.11 WLAN. Proc. of the Nat. Conf. on Comm. Kumar A, Patil D 1997 Stability and Throughput analysis of CDMA-ALOHA with Finite number of users and code sharing. Telecomm. Systems (a Baltzer Science Journal) 8: 257–275. Kumar A, Altman ...

  10. Wireless Power for Mobile Devices

    NARCIS (Netherlands)

    Waffenschmidt, E.

    2011-01-01

    Wireless power transfer allows a convenient, easy to use battery charging of mobile phones and other mobile devices. No hassle with cables and plugs, just place the device on a pad and that’s it. Such asystem even has the potential to become a standard charging solution. Where are the limits for

  11. Socially Aware Heterogeneous Wireless Networks.

    Science.gov (United States)

    Kosmides, Pavlos; Adamopoulou, Evgenia; Demestichas, Konstantinos; Theologou, Michael; Anagnostou, Miltiades; Rouskas, Angelos

    2015-06-11

    The development of smart cities has been the epicentre of many researchers' efforts during the past decade. One of the key requirements for smart city networks is mobility and this is the reason stable, reliable and high-quality wireless communications are needed in order to connect people and devices. Most research efforts so far, have used different kinds of wireless and sensor networks, making interoperability rather difficult to accomplish in smart cities. One common solution proposed in the recent literature is the use of software defined networks (SDNs), in order to enhance interoperability among the various heterogeneous wireless networks. In addition, SDNs can take advantage of the data retrieved from available sensors and use them as part of the intelligent decision making process contacted during the resource allocation procedure. In this paper, we propose an architecture combining heterogeneous wireless networks with social networks using SDNs. Specifically, we exploit the information retrieved from location based social networks regarding users' locations and we attempt to predict areas that will be crowded by using specially-designed machine learning techniques. By recognizing possible crowded areas, we can provide mobile operators with recommendations about areas requiring datacell activation or deactivation.

  12. Underwater optical wireless communication network

    Science.gov (United States)

    Arnon, Shlomi

    2010-01-01

    The growing need for underwater observation and subsea monitoring systems has stimulated considerable interest in advancing the enabling technologies of underwater wireless communication and underwater sensor networks. This communication technology is expected to play an important role in investigating climate change, in monitoring biological, biogeochemical, evolutionary, and ecological changes in the sea, ocean, and lake environments, and in helping to control and maintain oil production facilities and harbors using unmanned underwater vehicles (UUVs), submarines, ships, buoys, and divers. However, the present technology of underwater acoustic communication cannot provide the high data rate required to investigate and monitor these environments and facilities. Optical wireless communication has been proposed as the best alternative to meet this challenge. Models are presented for three kinds of optical wireless communication links: (a) a line-of-sight link, (b) a modulating retroreflector link, and (c) a reflective link, all of which can provide the required data rate. We analyze the link performance based on these models. From the analysis, it is clear that as the water absorption increases, the communication performance decreases dramatically for the three link types. However, by using the scattered light it was possible to mitigate this decrease in some cases. It is concluded from the analysis that a high-data-rate underwater optical wireless network is a feasible solution for emerging applications such as UUV-to-UUV links and networks of sensors, and extended ranges in these applications could be achieved by applying a multi-hop concept.

  13. Data centric wireless sensor networks

    NARCIS (Netherlands)

    Dulman, S.O.; Havinga, Paul J.M.

    2005-01-01

    The vision of wirteless sensing systems requires the development of devices and technologies that can be pervasive without being intrusive. The basic component of such a smart environment will be a small node with sensing and wireless communications capabilities, able to organize itself flexibly

  14. Wireless Crew Communication Feasibility Assessment

    Science.gov (United States)

    Archer, Ronald D.; Romero, Andy; Juge, David

    2016-01-01

    Ongoing discussions with crew currently onboard the ISS as well as the crew debriefs from completed ISS missions indicate that issues associated with the lack of wireless crew communication results in increased crew task completion times and lower productivity, creates cable management issues, and increases crew frustration.

  15. ProLanGO: Protein Function Prediction Using Neural Machine Translation Based on a Recurrent Neural Network.

    Science.gov (United States)

    Cao, Renzhi; Freitas, Colton; Chan, Leong; Sun, Miao; Jiang, Haiqing; Chen, Zhangxin

    2017-10-17

    With the development of next generation sequencing techniques, it is fast and cheap to determine protein sequences but relatively slow and expensive to extract useful information from protein sequences because of limitations of traditional biological experimental techniques. Protein function prediction has been a long standing challenge to fill the gap between the huge amount of protein sequences and the known function. In this paper, we propose a novel method to convert the protein function problem into a language translation problem by the new proposed protein sequence language "ProLan" to the protein function language "GOLan", and build a neural machine translation model based on recurrent neural networks to translate "ProLan" language to "GOLan" language. We blindly tested our method by attending the latest third Critical Assessment of Function Annotation (CAFA 3) in 2016, and also evaluate the performance of our methods on selected proteins whose function was released after CAFA competition. The good performance on the training and testing datasets demonstrates that our new proposed method is a promising direction for protein function prediction. In summary, we first time propose a method which converts the protein function prediction problem to a language translation problem and applies a neural machine translation model for protein function prediction.

  16. Deployable Wireless Camera Penetrators

    Science.gov (United States)

    Badescu, Mircea; Jones, Jack; Sherrit, Stewart; Wu, Jiunn Jeng

    2008-01-01

    A lightweight, low-power camera dart has been designed and tested for context imaging of sampling sites and ground surveys from an aerobot or an orbiting spacecraft in a microgravity environment. The camera penetrators also can be used to image any line-of-sight surface, such as cliff walls, that is difficult to access. Tethered cameras to inspect the surfaces of planetary bodies use both power and signal transmission lines to operate. A tether adds the possibility of inadvertently anchoring the aerobot, and requires some form of station-keeping capability of the aerobot if extended examination time is required. The new camera penetrators are deployed without a tether, weigh less than 30 grams, and are disposable. They are designed to drop from any altitude with the boost in transmitting power currently demonstrated at approximately 100-m line-of-sight. The penetrators also can be deployed to monitor lander or rover operations from a distance, and can be used for surface surveys or for context information gathering from a touch-and-go sampling site. Thanks to wireless operation, the complexity of the sampling or survey mechanisms may be reduced. The penetrators may be battery powered for short-duration missions, or have solar panels for longer or intermittent duration missions. The imaging device is embedded in the penetrator, which is dropped or projected at the surface of a study site at 90 to the surface. Mirrors can be used in the design to image the ground or the horizon. Some of the camera features were tested using commercial "nanny" or "spy" camera components with the charge-coupled device (CCD) looking at a direction parallel to the ground. Figure 1 shows components of one camera that weighs less than 8 g and occupies a volume of 11 cm3. This camera could transmit a standard television signal, including sound, up to 100 m. Figure 2 shows the CAD models of a version of the penetrator. A low-volume array of such penetrator cameras could be deployed from an

  17. A Unified NET-MAC-PHY Cross-layer Framework for Performance Evaluation of Multi-hop Ad hoc WLANs

    Directory of Open Access Journals (Sweden)

    Rachid El-Azouzi

    2014-09-01

    Full Text Available Most of the existing works have been evaluated the performance of 802.11 multihop networks by considering the MAC layer or network layer separately. Knowing the nature of the multi-hop ad hoc networks, many factors in different layers are crucial for study the performance of MANET. In this paper we present a new analytic model for evaluating average end-to-end throughput in IEEE 802.11e multihop wireless networks. In particular, we investigate an intricate interaction among PHY, MAC and Network layers. For instance, we incorporate carrier sense threshold, transmission power, contention window size, retransmissions retry limit, multi rates, routing protocols and network topology together. We build a general cross-layered framework to represent multi-hop ad hoc networks with asymmetric topology and asymmetric traffic. We develop an analytical model to predict throughput of each connection as well as stability of forwarding queues at intermediate nodes in saturated networks. To the best of our knowledge, it seems that our work is the first wherein general topology and asymmetric parameters setup are considered in PHY/MAC/Network layers. Performance of such a system is also evaluated through simulation. We show that performance measures of the MAC layer are affected by the traffic intensity of flows to be forwarded. More precisely, attempt rate and collision probability are dependent on traffic flows, topology and routing.

  18. Comparisons process-to-bay level peer-to-peer network delay in IEC 61850 substation communication systems

    Directory of Open Access Journals (Sweden)

    Nasser Hasan Ali

    2014-12-01

    Full Text Available This paper presents the application of IEC 61850 protocol in electrical power engineering industry for data communication systems between substations. This IEC 61850 protocol presents new challenges for real-time communication performance between Intelligent Electronic Devices (IEDs within substation because of the Generic Object Oriented Substation Event (GOOSE messages. The analyses of substation Ethernet and WLAN (wireless LAN communication delay, its impact factors, various methods and different network topologies which can improve the real-time performance are discussed. For basic analysis of data flow within a substation, the Optimized Network Engineering Tool (OPNET software is used. The process-to-bay level network simulation model is performed by using the OPNET software. The Ethernet delay and WLAN peer-to-peer performance of the process-to-bay level network simulation results are analyzed which is based on AP (access point, switched, shared Ethernet network or peer-to-peer network.

  19. A mobile field-work data collection system for the wireless era of health surveillance

    Directory of Open Access Journals (Sweden)

    Marianne Forsell

    2011-02-01

    Full Text Available In many countries or regions the capacity of health care resources is below the needs of the population and new approaches for health surveillance are needed. Innovative projects, utilizing wireless communication technology, contribute to reliable methods for field-work data collection and reporting to databases. The objective was to describe a new version of a wireless IT-support system for field-work data collection and administration. The system requirements were drawn from the design objective and translated to system functions. The system architecture was based on field-work experiences and administrative requirements. The Smartphone devices were HTC Touch Diamond2s, while the system was based on a platform with Microsoft .NET components, and a SQL Server 2005 with Microsoft Windows Server 2003 operating system. The user interfaces were based on .NET programming, and Microsoft Windows Mobile operating system. A synchronization module enabled download of field data to the database, via a General Packet Radio Services (GPRS to a Local Area Network (LAN interface. The field-workers considered the here-described applications user-friendly and almost self-instructing. The office administrators considered that the back-office interface facilitated retrieval of health reports and invoice distribution. The current IT-support system facilitates short lead times from field-work data registration to analysis, and is suitable for various applications. The advantages of wireless technology, and paper-free data administration need to be increasingly emphasized in development programs, in order to facilitate reliable and transparent use of limited resources.

  20. Wireless and mobile systems in telemedicine

    Directory of Open Access Journals (Sweden)

    Reza Safdari

    2012-12-01

    Full Text Available Background: It is necessary to deploy mobile and wireless systems in healthcare, because they have many benefits for healthcare systems. The objectives of this article were introducing various systems, applications, and standards of the wireless and mobile telemedicine. Material and Methods: This review study was conducted in 2010. To conduct the study, published articles in the years 2005 to 2012, in English with an emphasis on wireless and mobile technologies in health were studied. Search was done with key words include telemedicine, wireless health systems, health and telecommunications technology in databases including Pubmed, Science Direct, Google Scholar, Web of Sciences, Proquest. The collected data were analyzed. Results: Telemedicine system in the ambulance, telemedicine systems in space, telecardiology systems, EEG system, ultrasound system are some types of wireless and mobile systems in telemedicine. PDA-based mobile and wireless telemedicine application, based PDA drug application, and patient tracking application are some of wireless and mobile applications of telemedicine. The most important standards of wireless and mobile telemedicine are HL7, DICOM, SNOMed, and ICD-9-CM. Conclusion: There are many challenges in the wireless and mobile systems in telemedicine, despite the many benefits. Slow speed in sending pictures and video, lack of attention to the privacy in the design of these systems, environmental variables and the number of users during the day are some of these challenges. It is recommended to consider these challenges during the planning and designing of wireless and mobile systems in telemedicine.

  1. A Real-Time GPP Software-Defined Radio Testbed for the Physical Layer of Wireless Standards

    Directory of Open Access Journals (Sweden)

    Schiphorst R

    2005-01-01

    Full Text Available We present our contribution to the general-purpose-processor-(GPP-based radio. We describe a baseband software-defined radio testbed for the physical layer of wireless LAN standards. All physical layer functions have been successfully mapped on a Pentium 4 processor that performs these functions in real time. The testbed consists of a transmitter PC with a DAC board and a receiver PC with an ADC board. In our project, we have implemented two different types of standards on this testbed, a continuous-phase-modulation-based standard, Bluetooth, and an OFDM-based standard, HiperLAN/2. However, our testbed can easily be extended to other standards, because the only limitation in our testbed is the maximal channel bandwidth of 20 MHz and of course the processing capabilities of the used PC. The transmitter functions require at most 714 M cycles per second and the receiver functions need 1225 M cycles per second on a Pentium 4 processor. In addition, baseband experiments have been carried out successfully.

  2. Análise Crítica do Discurso na Propaganda de Lançamento do Citroën C3 Picasso

    Directory of Open Access Journals (Sweden)

    Edson Roberto Scharf

    2014-08-01

    Full Text Available O objetivo deste estudo foi identificar o tipo de propaganda veiculada no lançamento de novos produtos do setor automobilístico no Brasil. A campanha publicitária ‘Citroën C3 Picasso. A vida elevada ao cubo’ foi a plataforma de estudo. A análise crítica de discurso segundo os preceitos de Fairclough (1995 foi adotada como método. As peças publicitárias evidenciaram que a linguagem da propaganda no lançamento de produtos no setor automobilístico é de teor emocional. Os resultados obtidos confirmaram o uso da propaganda transformativa como protagonista da campanha publicitária de lançamento de determinado automóvel no Brasil. DOI: 10.5585/remark.v13i3.2525

  3. Energy-efficient digital and wireless IC design for wireless smart sensing

    Science.gov (United States)

    Zhou, Jun; Huang, Xiongchuan; Wang, Chao; Tae-Hyoung Kim, Tony; Lian, Yong

    2017-10-01

    Wireless smart sensing is now widely used in various applications such as health monitoring and structural monitoring. In conventional wireless sensor nodes, significant power is consumed in wirelessly transmitting the raw data. Smart sensing adds local intelligence to the sensor node and reduces the amount of wireless data transmission via on-node digital signal processing. While the total power consumption is reduced compared to conventional wireless sensing, the power consumption of the digital processing becomes as dominant as wireless data transmission. This paper reviews the state-of-the-art energy-efficient digital and wireless IC design techniques for reducing the power consumption of the wireless smart sensor node to prolong battery life and enable self-powered applications.

  4. Análisis de seguridad de una muestra de redes WLAN en la ciudad de Tunja, Boyacá, Colombia

    Directory of Open Access Journals (Sweden)

    Julián Alberto Monsalve-Pulido

    2015-01-01

    Full Text Available Éste documento presenta resultados de un aná lisis de seguridad de redes WLAN en la ciudad de Tunja Boyacá Colombia basado en un a muestra aleatoria distribuida en toda la Ciudad. El estudio es resultado de investigación del proyecto “Diagnóstico de segurida d informática aplicado a una muestra de organizac iones de la ciudad de Tunja” financiado por la Universidad Santo Tomás Seccional Tunja. La información recolectada y analizada se obtuvo mediante las técnicas Wa rchalking y Wardriving en una representación significativa de redes inalámbricas de empre sas públicas, privadas, entidades educativas y hogares ubicados geográficamente en diferentes sectores de la ciudad. Como re sultado de la investigación se demostró di ferentes niveles de riesgo con respecto a configuraciones de tecnología de algunos dispos itivos de entidades públicas, privadas y sectores residenciales, por último se r ealizaron algunas recomendaciones y conclusiones que mej orarán el nivel de seguridad por medio de buenas prácticas a nivel de configuraci ón y uso de estas redes.

  5. Adaptive Naive Bayes classification for wireless sensor networks

    NARCIS (Netherlands)

    Zwartjes, G.J.

    2017-01-01

    Wireless Sensor Networks are tiny devices equipped with sensors and wireless communication. These devices observe environments and communicatie about these observations. Machine Learning techniques are of interest for Wireless Sensor Network applications since they can reduce the amount of needed

  6. Estimating the Theoretical Value for LAN Network Throughput Based Power Line Communications Technology Under the Homeplug 1.0 Standard

    Directory of Open Access Journals (Sweden)

    Martha Fabiola Contreras Higuera

    2013-06-01

    Full Text Available Power Line Communications (PLC refers to a group of technologies that allow to establish communication processes under the use of the grid as a physical means of transmission. The use of the grid as a physical means of transmission of information is not a new idea. Until a few years ago, the use of PLC had been limited to the implementation of solutions of control, automation and monitoring of sensors; which did not require a high bandwidth for its operation.During the late 1990s due to the new technological developments and the need to implement new alternatives for transfer of information, it was possible to reach speeds on the order of the Mbps, establishing the possibility of making use of the electricity network as a network of access. The current state of technology PLC allows to reach speeds of up to 200Mbps, which has enabled the transformation of the grid in a true network of band wide, capable of supporting data, voice and video provided by a telecommunications operator. The use of PLC-based network adapters allow easily design LANs and broadband communications through the electrical network, making any outlet in a point of connection for the user, without the need for wiring additional to existing ones.  The electrical network is a structure which so far has been exclusively used for the transport of electrical energy. However, it is possible to make use of this network in processes of communication and transmission of information such as: voice, data and video; Bearing in mind that grid had not been designed for this purpose. The performance is without doubt one of the aspects of greatest interest in the global analysis in networks LAN, due to the effect it produces on the end user. Basically, the most common parameters for evaluating the performance of a network are: Throughput, use of the canal and various measures of retardation. In this article is presented a simple analysis of the HomePlug 1.0 standard applied to the

  7. Performance Analysis of IIUM Wireless Campus Network

    International Nuclear Information System (INIS)

    Latif, Suhaimi Abd; Masud, Mosharrof H; Anwar, Farhat

    2013-01-01

    International Islamic University Malaysia (IIUM) is one of the leading universities in the world in terms of quality of education that has been achieved due to providing numerous facilities including wireless services to every enrolled student. The quality of this wireless service is controlled and monitored by Information Technology Division (ITD), an ISO standardized organization under the university. This paper aims to investigate the constraints of wireless campus network of IIUM. It evaluates the performance of the IIUM wireless campus network in terms of delay, throughput and jitter. QualNet 5.2 simulator tool has employed to measure these performances of IIUM wireless campus network. The observation from the simulation result could be one of the influencing factors in improving wireless services for ITD and further improvement

  8. Introductory survey for wireless infrared communications

    Directory of Open Access Journals (Sweden)

    Munsif Ali Jatoi

    2014-08-01

    Full Text Available Wireless infrared communications can be defined as the propagation of light waves in free space using infrared radiation whose range is 400–700 nm. This range corresponds to frequencies of hundreds of terahertz, which is high for higher data rate applications. Wireless infrared is applied for higher data rates applications such as wireless computing, wireless video and wireless multimedia communication applications. Introduced by Gfeller, this field has grown with different link configurations, improved transmitter efficiency, increased receiver responsivity and various multiple access techniques for improved quality. Errors are caused because of background light, which causes degradation overall system performance. Error correction techniques are used to remove the errors caused during transmission. This study provides a brief account on field theory used for error correction in wireless infrared systems. The results are produced in terms of bit error rate and signal-to-noise ratio for various bit lengths to show the ability of encoding and decoding algorithms.

  9. Wireless Technology Application to Nuclear Power Plants

    International Nuclear Information System (INIS)

    Lee, Jeong Kweon; Jeong, See Chae; Jeong, Ki Hoon; Oh, Do Young; Kim, Jae Hack

    2009-01-01

    Wireless technologies are getting widely used in various industrial processes for equipment condition monitoring, process measurement and other applications. In case of Nuclear Power Plant (NPP), it is required to review applicability of the wireless technologies for maintaining plant reliability, preventing equipment failure, and reducing operation and maintenance costs. Remote sensors, mobile technology and two-way radio communication may satisfy these needs. The application of the state of the art wireless technologies in NPPs has been restricted because of the vulnerability for the Electromagnetic Interference and Radio Frequency Interference (EMI/RFI) and cyber security. It is expected that the wireless technologies can be applied to the nuclear industry after resolving these issues which most of the developers and vendors are aware of. This paper presents an overview and information on general wireless deployment in nuclear facilities for future application. It also introduces typical wireless plant monitoring system application in the existing NPPs

  10. mm-Wave Hybrid Photonic Wireless Links for Ultra-High Speed Wireless Transmissions

    DEFF Research Database (Denmark)

    Rommel, Simon; Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

    Hybrid photonic-wireless transmission schemes in the mm-wave frequency range are promising candidates to enable the multi-gigabit per second data communications required from wireless and mobile networks of the 5th and future generations. Large FCC spectrum allocations for wireless transmission...

  11. Application and promotion of wireless charging technology

    OpenAIRE

    Yan, Kaijun

    2014-01-01

    The aim of this thesis is to study wireless charging technology and analyze the application and promotion of each technology. This technology is based on Faraday’s electromagnetic in 1830s. It is not a new technology but it is developing high speed nowadays. This thesis introduces four mainstream types of wireless charging technology and three main-stream standards, and analyzes their features and development status. Wireless charging technology has been applied to some products, suc...

  12. Computer-Based Wireless Advertising Communication System

    Directory of Open Access Journals (Sweden)

    Anwar Al-Mofleh

    2009-10-01

    Full Text Available In this paper we developed a computer based wireless advertising communication system (CBWACS that enables the user to advertise whatever he wants from his own office to the screen in front of the customer via wireless communication system. This system consists of two PIC microcontrollers, transmitter, receiver, LCD, serial cable and antenna. The main advantages of the system are: the wireless structure and the system is less susceptible to noise and other interferences because it uses digital communication techniques.

  13. Application opportunities in wireless communications. Final report

    International Nuclear Information System (INIS)

    Abbott, R.E.; Blevins, R.P.; Olmstead, C.

    1998-07-01

    This report presents the results of examinations of wireless technologies and applications that may offer potential to utilities. Five different wireless technology areas are reviewed. Three areas--Communication Networks, Monitored Security Services, and Home Automation--potentially represent new business ventures for utilities. Two areas--Automatic Vehicle Location and Automated Field-Force Management--represent wireless applications with potential for reduced operating costs and improved customer relations

  14. Design and security of small wireless network

    OpenAIRE

    Žižka, Ladislav

    2012-01-01

    This thesis deals with design and security of small wireless network. Main goal of the thesis is home network design and choice of optimal solution of wireless security. The thesis has four parts. The first part describes computer networks and network components in theory. Next part deals with network design, choosing of network components and setting of them. It also describes some functionalities of alternative firmware DD-WRT. The third part presents common wireless security and network an...

  15. Biomedical Wireless Ambulatory Crew Monitor

    Science.gov (United States)

    Chmiel, Alan; Humphreys, Brad

    2009-01-01

    A compact, ambulatory biometric data acquisition system has been developed for space and commercial terrestrial use. BioWATCH (Bio medical Wireless and Ambulatory Telemetry for Crew Health) acquires signals from biomedical sensors using acquisition modules attached to a common data and power bus. Several slots allow the user to configure the unit by inserting sensor-specific modules. The data are then sent real-time from the unit over any commercially implemented wireless network including 802.11b/g, WCDMA, 3G. This system has a distributed computing hierarchy and has a common data controller on each sensor module. This allows for the modularity of the device along with the tailored ability to control the cards using a relatively small master processor. The distributed nature of this system affords the modularity, size, and power consumption that betters the current state of the art in medical ambulatory data acquisition. A new company was created to market this technology.

  16. Wireless Augmented Reality Communication System

    Science.gov (United States)

    Devereaux, Ann (Inventor); Jedrey, Thomas (Inventor); Agan, Martin (Inventor)

    2016-01-01

    The system of the present invention is a highly integrated radio communication system with a multimedia co-processor which allows true two-way multimedia (video, audio, data) access as well as real-time biomedical monitoring in a pager-sized portable access unit. The system is integrated in a network structure including one or more general purpose nodes for providing a wireless-to-wired interface. The network architecture allows video, audio and data (including biomedical data) streams to be connected directly to external users and devices. The portable access units may also be mated to various non-personal devices such as cameras or environmental sensors for providing a method for setting up wireless sensor nets from which reported data may be accessed through the portable access unit. The reported data may alternatively be automatically logged at a remote computer for access and viewing through a portable access unit, including the user's own.

  17. Propagation Engineering in Wireless Communications

    CERN Document Server

    Ghasemi, Abdollah; Ghasemi, Farshid

    2012-01-01

    Wireless communications has seen explosive growth in recent decades, in a realm that is both broad and rapidly expanding to include satellite services, navigational aids, remote sensing, telemetering, audio and video broadcasting, high-speed data communications, mobile radio systems and much more. Propagation Engineering in Wireless Communications deals with the basic principles of radiowaves propagation for frequency bands used in radio-communications, offering descriptions of new achievements and newly developed propagation models. The book bridges the gap between theoretical calculations and approaches, and applied procedures needed for advanced radio links design. The primary objective of this two-volume set is to demonstrate the fundamentals, and to introduce propagation phenomena and mechanisms that engineers are likely to encounter in the design and evaluation of radio links of a given type and operating frequency. Volume one covers basic principles, along with tropospheric and ionospheric propagation,...

  18. Mobility needs and wireless solutions

    DEFF Research Database (Denmark)

    Saugstrup, Dan; Henten, Anders

    The main purpose of this report is to spell out a methodological approach to the analysis of user needs with respect to mobility. Furthermore, this methodological approach is used in an exemplary analysis of the relationship between user needs and technology solutions offered by different wireless...... technologies. The report is based on a research approach, emphasizing important aspects in relation to developing more user oriented mobile services and applications in a heterogeneous network environment. As a staring point, Scandinavian research within the field of social science concerning mobility...... is described and discussed. Furthermore different wireless technologies are briefly described and discussed in relation to possible transmission capacities and coverage areas. In addition to this, a preliminary framework regarding the implications of mobility on the use and development of mobile services...

  19. Passive Wireless SAW Humidity Sensors, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal describes the preliminary development of passive wireless surface acoustic wave (SAW) based humidity sensors for NASA application to distributed...

  20. EEM{sup TM} wireless supervision

    Energy Technology Data Exchange (ETDEWEB)

    Bilic, H. [Ericsson-Nikola Tesla d.d. Zagreb (Croatia)

    2000-07-01

    By adding the GSM network to the communication level of Energy Management systems, energy operating centres (EOC) can offer wireless access to the supervised equipment. Furthermore EOC can profit from rapid service development in the GSM networks. With implementation of GPRS to the GSM network EOC can instantly offer wireless access to external IP based networks such as Internet and corporate Intranets. The author describes architecture and key characteristic of Ericsson EnergyMaster{sup TM} (EEM{sup TM}) system for Energy Management, how and where to implement wireless supervision, wireless access to IP addresses and also how to implement new services provided by the GSM network. (orig.)