284 research outputs found

    A Physical Layer Secured Key Distribution Technique for IEEE 802.11g Wireless Networks

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    Key distribution and renewing in wireless local area networks is a crucial issue to guarantee that unauthorized users are prevented from accessing the network. In this paper, we propose a technique for allowing an automatic bootstrap and periodic renewing of the network key by exploiting physical layer security principles, that is, the inherent differences among transmission channels. The proposed technique is based on scrambling of groups of consecutive packets and does not need the use of an initial authentication nor automatic repeat request protocols. We present a modification of the scrambling circuits included in the IEEE 802.11g standard which allows for a suitable error propagation at the unauthorized receiver, thus achieving physical layer security.Comment: 9 pages, 7 figures. Accepted for publication in IEEE Wireless Communications Letters. Copyright transferred to IEE

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

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    This thesis investigates the quality of audio 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 calls or by securing the WLAN with transport mode Internet Protocol Security (IPsec) is quantified. Audio quality over an IEEE 802.11n draft 2.0 WLAN is also compared to that of IEEE 802.11b and IEEE 802.11g WLANs under the same conditions. Audio quality is evaluated by following International Telecommunication Union Telecommunication Standardization Sector (ITU-T) Recommendation P.800, where human subjects rate audio clips recorded during various WLAN configurations. The Mean Opinion Score (MOS) is calculated as the average audio quality score given for each WLAN configuration. An 85% confidence interval is calculated for each MOS. Results suggest that audio quality over an IEEE 802.11n draft 2.0 WLAN is not higher than over an IEEE 802.11b WLAN when up to 10 simultaneous G.711 calls occur. A linear regression of the subjective scores also suggest that an IEEE 802.11n draft 2.0 WLAN can sustain an MOS greater than 3.0 (fair quality) for up to 75 simultaneous G.711 calls secured with WPA2, or up to 40 calls secured with both WPA2 and transport mode IPsec. The data strongly suggest that toll quality audio (MOS ≥ 4.0) is not currently practical over IEEE 802.11 WLANs secured with WPA2, even with the G.711 codec

    Energy-efficient Wi-Fi Gateways for Federated Residential Networks

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    Wireless Handheld Solution for the Gaming Industry

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    of the essential elements of success in the gaming industry is the requirement of providing exceptional customer service. Technology plays a significant role in bringing state of the art solutions that enhance the overall customer experience. Currently a guest must go through multiple steps and a variety of departments to simply resolve issues with their player accounts (loyalty programs), update customer profiles, book hotel and restaurant reservations, sign up for promotions, etc. In order to effectively take care of these customers in both a timely and efficient manner, a wireless handheld device is needed that employees can carry with them to resolve and address these concerns. This project is aimed at identifying the proper wireless infrastructure for the gaming environment and also the wireless handheld device, such as an Ultra Mobile PC (UMPC) to effectively and efficiently take care of customers

    Future strategic plan analysis for integrating distributed renewable generation to smart grid through wireless sensor network: Malaysia prospect

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    AbstractIntegration of Distributed Renewable Generation (DRG) to the future Smart Grid (SG) is one of the important considerations that is highly prioritized in the SG development roadmap by most of the countries including Malaysia. The plausible way of this integration is the enhancement of information and bidirectional communication infrastructure for energy monitoring and controlling facilities. However, urgency of data delivery through maintaining critical time condition is not crucial in these facilities. In this paper, we have surveyed state-of-the-art protocols for different Wireless Sensor Networks (WSNs) with the aim of realizing communication infrastructure for DRG in Malaysia. Based on the analytical results from surveys, data communication for DRG should be efficient, flexible, reliable, cost effective, and secured. To meet this achievement, IEEE802.15.4 supported ZigBee PRO protocol together with sensors and embedded system is shown as Wireless Sensor (WS) for DRG bidirectional network with prospect of attaining data monitoring facilities. The prospect towards utilizing ZigBee PRO protocol can be a cost effective option for full integration of intelligent DRG and small scale Building-Integrated Photovoltaic (BIPV)/Feed-in-Tariff (FiT) under SG roadmap (Phase4: 2016–2017) conducted by Malaysia national utility company, Tenaga Nasional Berhad (TNB). Moreover, we have provided a direction to utilize the effectiveness of ZigBee-WS network with the existing optical communication backbone for data importing from the end DRG site to the TNB control center. A comparative study is carried out among developing countries on recent trends of SG progress which reveals that some common projects like smart metering and DRG integration are on priority

    Design and evaluation of a self-configuring wireless mesh network architecture

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    Wireless network connectivity plays an increasingly important role in supporting our everyday private and professional lives. For over three decades, self-organizing wireless multi-hop ad-hoc networks have been investigated as a decentralized replacement for the traditional forms of wireless networks that rely on a wired infrastructure. However, despite the tremendous efforts of the international wireless research community and widespread availability of devices that are able to support these networks, wireless ad-hoc networks are hardly ever used. In this work, the reasons behind this discrepancy are investigated. It is found that several basic theoretical assumptions on ad-hoc networks prove to be wrong when solutions are deployed in reality, and that several basic functionalities are still missing. It is argued that a hierarchical wireless mesh network architecture, in which specialized, multi-interfaced mesh nodes form a reliable multi-hop wireless backbone for the less capable end-user clients is an essential step in bringing the ad-hoc networking concept one step closer to reality. Therefore, in a second part of this work, algorithms increasing the reliability and supporting the deployment and management of these wireless mesh networks are developed, implemented and evaluated, while keeping the observed limitations and practical considerations in mind. Furthermore, the feasibility of the algorithms is verified by experiment. The performance analysis of these protocols and the ability to deploy the developed algorithms on current generation off-the-shelf hardware indicates the successfulness of the followed research approach, which combines theoretical considerations with practical implementations and observations. However, it was found that there are also many pitfalls to using real-life implementation as a research technique. Therefore, in the last part of this work, a methodology for wireless network research using real-life implementation is developed, allowing researchers to generate more reliable protocols and performance analysis results with less effort

    A wireless sensor and actuator network for improving the electrical power grid dependability

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    This paper presents an overview of a Wireless Sensor and Actuator Network (WSAN) used to monitor an electrical power grid distribution infrastructure. The WSAN employs appropriate sensors to monitor key grid components, integrating both safety and security services, which improve the grid distribution dependability. The supported applications include, among others, video surveillance of remote secondary substations, which imposes special requirements from the point of view of quality of service and reliability. The paper presents the hardware and software architecture of the system together with performance results

    Advanced Wireless LAN

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    The past two decades have witnessed starling advances in wireless LAN technologies that were stimulated by its increasing popularity in the home due to ease of installation, and in commercial complexes offering wireless access to their customers. This book presents some of the latest development status of wireless LAN, covering the topics on physical layer, MAC layer, QoS and systems. It provides an opportunity for both practitioners and researchers to explore the problems that arise in the rapidly developed technologies in wireless LAN

    Investigation of Wireless LAN for IEC 61850 based Smart Distribution Substations

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    The IEC 61850 standard is receiving acceptance worldwide to deploy Ethernet Local Area Networks (LANs) for electrical substations in a smart grid environment. With the recent growth in wireless communication technologies, wireless Ethernet or Wireless LAN (WLAN), standardized in IEEE 802.11, is gaining interest in the power industry for substation automation applications, especially at the distribution level. Low Voltage (LV) / Medium Voltage (MV) distribution substations have comparatively low time-critical performance requirements. At the same time, expensive but high data-rate fiber-based Ethernet networks may not be a feasible solution for the MV/LV distribution network. Extensive work is carried out to assess wireless LAN technologies for various IEC 61850 based smart distribution substation applications: control and monitoring; automation and metering; and over-current protection. First, the investigation of wireless LANs for various smart distribution substation applications was initiated with radio noise-level measurements in total five (27.6 and 13.8 kV) substations owned by London Hydro and Hydro One in London, ON, Canada. The measured noise level from a spectrum analyzer was modeled using the Probability Distribution Function (PDF) tool in MATLAB, and parameters for these models in the 2.4 GHz band and 5.8 GHz band were obtained. Further, this measured noise models were used to simulate substation environment in OPNET (the industry-trusted communication networking simulation) tool. In addition, the efforts for developing dynamic models of WLAN-enabled IEC 61850 devices were initiated using Proto-C programming in OPNET tool. The IEC 61850 based devices, such as Protection and Control (P&C) Intelligent Electronic Devices (IEDs) and Merging Unit (MU) were developed based on the OSI-7 layer stack proposed in IEC 61850. The performance of various smart distribution substation applications was assessed in terms of average and maximum message transfer delays and throughput. The work was extended by developing hardware prototypes of WLAN enabled IEC 61850 devices in the R&D laboratory at University of Western Ontario, Canada. P&C IED, MU, Processing IED, and Echo IED were developed using industrial embedded computers over the QNX Real Time Operating System (RTOS) platform. The functions were developed using hard real-time multithreads, timers, and so on to communicate IEC 61850 application messages for analyzing WLAN performance in terms of Round Trip Time (RTT) and throughput. The laboratory was set up with WLAN-enabled IEC 61850 devices, a commercially available WLAN Access Point (AP), noise sources, and spectrum and network analyzers. Performance of various smart distribution substation applications is examined within the developed laboratory. Finally, the performance evaluation was carried out in real-world field testing at 13.8 and 27.6 kV distribution substations, by installing the devices in substation control room and switchyard. The RTT of IEC 61850 based messages and operating time of the overcurrent protection using WLAN based communication network were evaluated in the harsh environment of actual distribution substations. The important findings from the exhaustive investigation were discussed throughout this work
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