423 research outputs found

    Experimenting with commodity 802.11 hardware: overview and future directions

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    The huge adoption of 802.11 technologies has triggered a vast amount of experimentally-driven research works. These works range from performance analysis to protocol enhancements, including the proposal of novel applications and services. Due to the affordability of the technology, this experimental research is typically based on commercial off-the-shelf (COTS) devices, and, given the rate at which 802.11 releases new standards (which are adopted into new, affordable devices), the field is likely to continue to produce results. In this paper, we review and categorise the most prevalent works carried out with 802.11 COTS devices over the past 15 years, to present a timely snapshot of the areas that have attracted the most attention so far, through a taxonomy that distinguishes between performance studies, enhancements, services, and methodology. In this way, we provide a quick overview of the results achieved by the research community that enables prospective authors to identify potential areas of new research, some of which are discussed after the presentation of the survey.This work has been partly supported by the European Community through the CROWD project (FP7-ICT-318115) and by the Madrid Regional Government through the TIGRE5-CM program (S2013/ICE-2919).Publicad

    A high-speed wireless network used for telemedicine

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    Nowadays, there is growing interest in using telemedicine to provide non-face-to-face healthcare for patients. The emergence and development of WLAN (Wireless Local Area Network) technology, which supports high-speed wireless communications within the existing Intranet that covers the healthcare system, makes it possible to provide routine body check-ups for patients who need long-term monitoring. In this thesis, we present the design of a wireless telemedicine system using WLAN technology. [Continues.

    Electromagnetic Propagation Prediction Inside Aircraft Cabins

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    Electromagnetic propagation models for signal strength prediction within aircraft cabins are essential for evaluating and designing a wireless communication system to be implemented onboard aircraft. There are many commercially available software packages for predicting wireless system performance in conventional indoor environments. It is of interest to examine the available software to determine if the aircraft\u27s electromagnetic environment (EME) can be modeled successfully without developing an aircraft specific prediction tool. EnterprisePlanner ®, a registered product of Wireless Valley Communications, Incorporated, was selected for the present effort. The performance of the prediction model was evaluated through a comparison with field measurements taken on the aircraft. It was concluded that the prediction model can accurately predict power propagation throughout the cabin. This prediction tool can enhance researchers\u27 understanding of power propagation within aircraft cabins and will aid in future research

    Improving the Performance of Wireless LANs

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    This book quantifies the key factors of WLAN performance and describes methods for improvement. It provides theoretical background and empirical results for the optimum planning and deployment of indoor WLAN systems, explaining the fundamentals while supplying guidelines for design, modeling, and performance evaluation. It discusses environmental effects on WLAN systems, protocol redesign for routing and MAC, and traffic distribution; examines emerging and future network technologies; and includes radio propagation and site measurements, simulations for various network design scenarios, numerous illustrations, practical examples, and learning aids

    Saving Energy in Mobile Devices for On-Demand Multimedia Streaming -- A Cross-Layer Approach

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    This paper proposes a novel energy-efficient multimedia delivery system called EStreamer. First, we study the relationship between buffer size at the client, burst-shaped TCP-based multimedia traffic, and energy consumption of wireless network interfaces in smartphones. Based on the study, we design and implement EStreamer for constant bit rate and rate-adaptive streaming. EStreamer can improve battery lifetime by 3x, 1.5x and 2x while streaming over Wi-Fi, 3G and 4G respectively.Comment: Accepted in ACM Transactions on Multimedia Computing, Communications and Applications (ACM TOMCCAP), November 201

    Flexi-WVSNP-DASH: A Wireless Video Sensor Network Platform for the Internet of Things

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    abstract: Video capture, storage, and distribution in wireless video sensor networks (WVSNs) critically depends on the resources of the nodes forming the sensor networks. In the era of big data, Internet of Things (IoT), and distributed demand and solutions, there is a need for multi-dimensional data to be part of the Sensor Network data that is easily accessible and consumable by humanity as well as machinery. Images and video are expected to become as ubiquitous as is the scalar data in traditional sensor networks. The inception of video-streaming over the Internet, heralded a relentless research for effective ways of distributing video in a scalable and cost effective way. There has been novel implementation attempts across several network layers. Due to the inherent complications of backward compatibility and need for standardization across network layers, there has been a refocused attention to address most of the video distribution over the application layer. As a result, a few video streaming solutions over the Hypertext Transfer Protocol (HTTP) have been proposed. Most notable are Apple’s HTTP Live Streaming (HLS) and the Motion Picture Experts Groups Dynamic Adaptive Streaming over HTTP (MPEG-DASH). These frameworks, do not address the typical and future WVSN use cases. A highly flexible Wireless Video Sensor Network Platform and compatible DASH (WVSNP-DASH) are introduced. The platform's goal is to usher video as a data element that can be integrated into traditional and non-Internet networks. A low cost, scalable node is built from the ground up to be fully compatible with the Internet of Things Machine to Machine (M2M) concept, as well as the ability to be easily re-targeted to new applications in a short time. Flexi-WVSNP design includes a multi-radio node, a middle-ware for sensor operation and communication, a cross platform client facing data retriever/player framework, scalable security as well as a cohesive but decoupled hardware and software design.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

    IMPLEMENTATION OF WIRELESS LAN IN UTP

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    This paper, entitled Implementation ofWireless LAN in UTP environment, looks into the way to implement wireless network in UTP. The main objectives ofthis project are to provide mobile network and internet access using university's network system to students and lecturers and to make it easier and convenient for student to download lecture notes and for lecturers to upload them. Currently, there is no wireless LAN access in UTP environment that can be use by students and staff as alternative opportunity to access and share instant information. Therefore, this project research area is to find out the way to implement wireless LAN using secure Wi-Fi in UTP external environment. For this study, the scope is narrow down to the architecture and design ofwireless LAN network and its developing methodology. Anetwork simulation tool called Network Simulator version 2, or simply known as ns-2, is used to test the efficiency and functionality ofthe designed network. The outcome ofthis project is a good network architecture design that will give high network performance to all users in UTP
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