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Selected Areas in Communications, IEEE Journal on

Issue 1 • Date January 2009

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Displaying Results 1 - 11 of 11
  • IEEE Journal on Selected Areas in Communications

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  • Journal Editorial Board

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  • Body Area Networking: Technology and Applications

    Page(s): 1 - 4
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  • Cooperative Communications in Ultra-Wideband Wireless Body Area Networks: Channel Modeling and System Diversity Analysis

    Page(s): 5 - 16
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (559 KB) |  | HTML iconHTML  

    In this paper, we explore the application of cooperative communications in ultra-wideband (UWB) wireless body area networks (BANs), where a group of on-body devices may collaborate together to communicate with other groups of on-body equipment. Firstly, time-domain UWB channel measurements are presented to characterize the body-centric multipath channel and to facilitate the diversity analysis in a cooperative BAN (CoBAN). We focus on the system deployment scenario when the human subject is in the sitting posture. Important channel parameters such as the pathloss, power variation, power delay profile (PDP), and effective received power (ERP) crosscorrelation are investigated and statistically analyzed. Provided with the model preliminaries, a detailed analysis on the diversity level in a CoBAN is provided. Specifically, an intuitive measure is proposed to quantify the diversity gains in a single-hop cooperative network, which is defined as the number of independent multipaths that can be averaged over to detect symbols. As this measure provides the largest number of redundant copies of transmitted information through the body-centric channel, it can be used as a benchmark to access the performance bound of various diversity-based cooperative schemes in futuristic body sensor systems. View full abstract»

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  • Performance of UWB Receivers with Partial CSI Using a Simple Body Area Network Channel Model

    Page(s): 17 - 26
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (531 KB) |  | HTML iconHTML  

    Ultra wideband (UWB) communication is a very promising candidate for the use in wireless body area networks (BAN). The high UWB peak data rate allows for medium average data rates in combination with a very low duty cycle, which is the key for a very low power consumption. Devices in a wireless BAN require low complexity. Hence, mainly non-coherent receivers such as energy detector and transmitted-reference receiver are suited. In this paper, the symbol-wise maximum-likelihood (ML) detectors for pulse position modulation (PPM) and transmitted reference pulse amplitude modulation (TR PAM) are derived assuming partial channel state information (CSI) at the receiver. Additionally, also the ML detectors for a combination of PPM and TR PAM are presented. The performance of the derived receiver structures is evaluated using a novel BAN channel model not distinguishing line-of-sight and non line-of-sight situations. This simple channel model is based on 1100 channel measurements in the frequency range between 2 and 8 GHz, which were measured in an anechoic chamber. Using the BAN channel model, performance of the derived receiver structures is evaluated showing that the knowledge of the average power delay profile (APDP) at the receiver improves performance substantially. Requiring only slightly more complexity such receivers are a well suited alternative to non-coherent receivers for the use in a BAN. View full abstract»

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  • An Antennas and Propagation Approach to Improving Physical Layer Performance in Wireless Body Area Networks

    Page(s): 27 - 36
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3676 KB) |  | HTML iconHTML  

    A combined antennas and propagation study has been undertaken with a view to directly improving link conditions for wireless body area networks. Using tissue-equivalent numerical and experimental phantoms representative of muscle tissue at 2.45 GHz, we show that the node to node |S21| path gain performance of a new wearable integrated antenna (WIA) is up to 9 dB better than a conventional compact Printed-F antenna, both of which are suitable for integration with wireless node circuitry. Overall, the WIA performed extremely well with a measured radiation efficiency of 38% and an impedance bandwidth of 24%. Further benefits were also obtained using spatial diversity, with the WIA providing up to 7.7 dB of diversity gain for maximal ratio combining. The results also show that correlation was lower for a multipath environment leading to higher diversity gain. Furthermore, a diversity implementation with the new antenna gave up to 18 dB better performance in terms of mean power level and there was a significant improvement in level crossing rates and average fade durations when moving from a single-branch to a two-branch diversity system. View full abstract»

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  • Transmission Power Control in Body Area Sensor Networks for Healthcare Monitoring

    Page(s): 37 - 48
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (360 KB) |  | HTML iconHTML  

    This paper investigates the opportunities and challenges in the use of dynamic radio transmit power control for prolonging the lifetime of body-wearable sensor devices used in continuous health monitoring. We first present extensive empirical evidence that the wireless link quality can change rapidly in body area networks, and a fixed transmit power results in either wasted energy (when the link is good) or low reliability (when the link is bad). We quantify the potential gains of dynamic power control in body-worn devices by benchmarking off-line the energy savings achievable for a given level of reliability.We then propose a class of schemes feasible for practical implementation that adapt transmit power in real-time based on feedback information from the receiver. We profile their performance against the offline benchmark, and provide guidelines on how the parameters can be tuned to achieve the desired trade-off between energy savings and reliability within the chosen operating environment. Finally, we implement and profile our scheme on a MicaZ mote based platform, and also report preliminary results from the ultra-low-power integrated healthcare monitoring platform we are developing at Toumaz Technology. View full abstract»

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  • Modeling Service-Oriented Context Processing in Dynamic Body Area Networks

    Page(s): 49 - 57
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (885 KB) |  | HTML iconHTML  

    Context processing in Body Area Networks (BANs) faces unique challenges due to the user and node mobility, the need of real-time adaptation to the dynamic topological and contextual changes, and heterogeneous processing capabilities and energy constraints present on the available devices. This paper proposes a service-oriented framework for the execution of context recognition algorithms. We describe and theoretically analyze the performance of the main framework components, including the sensor network organization, service discovery, service graph construction, service distribution and mapping. The theoretical results are followed by the simulation of the proposed framework as a whole, showing the overall cost of dynamically distributing applications on the network. View full abstract»

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  • Energy-Efficient Information-Driven Coverage for Physical Movement Monitoring in Body Sensor Networks

    Page(s): 58 - 69
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    Advances in technology have led to the development of various light-weight sensor devices that can be woven into the physical environment of our daily lives. Such systems enable on-body and mobile health-care monitoring. Our interest particularly lies in the area of movement-monitoring platforms that operate with inertial sensors. In this paper, we introduce the notion of compatibility graphs and describe how they can be utilized for power optimization. We first formulate an action coverage problem that will consider the sensing coverage from a collaborative signal processing perspective. Our solution is capable of eliminating redundant sensor nodes while maintaining the quality of service. The problem we outline can be transformed into an NP-hard problem. Therefore, we propose an ILP formulation to attain a lower bound on the solution and a fast greedy technique. Moreover, we present a system for dynamically activating and deactivating sensor nodes in real time. We then use our graph representation to develop an efficient formulation for maximum lifetime. This formulation provides sufficient information for finding activation duties for each sensor node. Finally, we demonstrate the effectiveness of our techniques on data collected from several subjects. View full abstract»

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  • IEEE Communications Society 2009 Board of Governors

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  • Upcoming issues of the IEEE Journal on Selected Areas in Communications

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Aims & Scope

IEEE Journal on Selected Areas in Communications focuses on all telecommunications, including telephone, telegraphy, facsimile, and point-to-point television, by electromagnetic propagation.

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Meet Our Editors

Editor-in-Chief
Muriel Médard
MIT