Exploiting Diversity In Broadband Wireless Relay Networks
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Exploiting Diversity In Broadband Wireless Relay Networks
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Author : Qingxiong Deng
language : en
Publisher:
Release Date : 2012
Exploiting Diversity In Broadband Wireless Relay Networks written by Qingxiong Deng and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
Abstract: Fading is one of the most fundamental impairments to wireless communications. The standard approach to combating fading is by adding redundancy - or diversity - to help increase coverage and transmission speed. Motivated by the results in multiple-input multiple-output technologies, which are usually used at base stations or access points, cooperation commutation has been proposed to improve the performance of wireless networks which consist of low-cost single antenna devices. While the majority of the research in cooperative communication focuses on flat fading for its simplicity and easy analysis, in practice the underlying channels in broadband wireless communication systems such as cellular systems (UMTS/LTE) are more likely to exhibit frequency selective fading. In this dissertation, we consider a frequency selective fading channel model and explore distributed diversity techniques in broadband wireless relay networks, with consideration to practical issues such as channel estimation and complexity-performance tradeoffs. We first study a system model with one source, one destination and multiple decode-and-forward (DF) relays which share a single channel orthogonal to the source. We derive the diversity-multiplexing tradeoff (DMT) for several relaying strategies: best relay selection, random relay selection, and the case when all decoding relays participate. The best relay selection method selects the relay in the decoding set with the largest sum-squared relay-to-destination channel coefficients. This scheme can achieve the optimal DMT of the system at the expense of higher complexity, compared to the other two relaying strategies which do not always exploit the spatial diversity offered by the relays. Different from flat fading, we find special cases when the three relaying strategies have the same DMT. We further present a transceiver design and prove it can achieve the optimal DMT asymptotically. Monte Carlo simulations are presented to corroborate the theoretical analysis. We provide a detailed performance comparison of the three relaying strategies in channels encountered in practice. The work has been extended to systems with multiple amplify-and-forward relays. We propose two relay selection schemes with maximum likelihood sequential estimator and linear zero- forcing equalization at the destination respectively and both schemes can asymptotically achieve the optimal DMT. We next extend the results in the two-hop network, as previously studied, to multi-hop networks. In particular, we consider the routing problem in clustered multi-hop DF relay networks since clustered multi-hop wireless networks have attracted significant attention for their robustness to fading, hierarchical structure, and ability to exploit the broadcast nature of the wireless channel. We propose an opportunistic routing (or relay selection) algorithm for such networks. In contrast to the majority of existing approaches to routing in clustered networks, our algorithm only requires channel state information in the final hop, which is shown to be essential for reaping the diversity offered by the channel. In addition to exploiting the available diversity, our simple cross-layer algorithm has the flexibility to satisfy an additional routing objective such as maximization of network lifetime. We demonstrate through analysis and simulation that our proposed routing algorithm attains full diversity under certain conditions on the cluster sizes, and its diversity is equal to the diversity of more complicated approaches that require full channel state information. The final part of this dissertation considers channel estimation in relay networks. Channel state information is vital for exploiting diversity in cooperative networks. The existing literature on cooperative channel estimation assumes that block lengths are long and that channel estimation takes place within a fading block. However, if the forwarding delay needs to be reduced, short block lengths are preferred, and adaptive estimation through multiple blocks is required. In particular, we consider estimating the relay-to-destination channel in DF relay systems for which the presence of forwarded information is probabilistic since it is unknown whether the relay participates in the forwarding phase. A detector is used so that the update of the least mean square channel estimate is made only when the detector decides the presence of training data. We use the generalized likelihood ratio test and focus on the detector threshold for deciding whether the training sequence is present. We also propose a heuristic objective function which leads to a proper threshold to improve the convergence speed and reduce the estimation error. Extensive numerical results show the superior performance of using this threshold as opposed to fixed thresholds.
Ofdm Based Broadband Wireless Networks
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Author : Hui Liu
language : en
Publisher: John Wiley & Sons
Release Date : 2005-11-22
Ofdm Based Broadband Wireless Networks written by Hui Liu and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005-11-22 with Computers categories.
OFDM-based Broadband Wireless Networks covers the latest technological advances in digital broadcasting, wireless LAN, and mobile networks to achieve high spectral efficiency, and to meet peak requirements for multimedia traffic. The book emphasizes the OFDM modem, air-interface, medium access-control (MAC), radio link protocols, and radio network planning. An Instructor Support FTP site is available from the Wiley editorial department.
Broadband Wireless Access Networks For 4g Theory Application And Experimentation
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Author : Santos, Raul Aquino
language : en
Publisher: IGI Global
Release Date : 2013-12-31
Broadband Wireless Access Networks For 4g Theory Application And Experimentation written by Santos, Raul Aquino and has been published by IGI Global this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-12-31 with Computers categories.
With the increased functionality demand for mobile speed and access in our everyday lives, broadband wireless networks have emerged as the solution in providing high data rate communications systems to meet these growing needs. Broadband Wireless Access Networks for 4G: Theory, Application, and Experimentation presents the latest trends and research on mobile ad hoc networks, vehicular ad hoc networks, and routing algorithms which occur within various mobile networks. This publication smartly combines knowledge and experience from enthusiastic scholars and expert researchers in the area of wideband and broadband wireless networks. Students, professors, researchers, and other professionals in the field will benefit from this books practical applications and relevant studies.
Mobile And Wireless Communications For Imt Advanced And Beyond
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Author : Afif Osseiran
language : en
Publisher: John Wiley & Sons
Release Date : 2011-08-08
Mobile And Wireless Communications For Imt Advanced And Beyond written by Afif Osseiran and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011-08-08 with Technology & Engineering categories.
A timely addition to the understanding of IMT-Advanced, this book places particular emphasis on the new areas which IMT-Advanced technologies rely on compared with their predecessors. These latest areas include Radio Resource Management, Carrier Aggregation, improved MIMO support and Relaying. Each technique is thoroughly described and illustrated before being surveyed in context of the LTE-Advanced standards. The book also presents state-of-the-art information on the different aspects of the work of standardization bodies (such as 3GPP and IEEE), making global links between them. Explores the latest research innovations to assess the future of the LTE standard Covers the latest research techniques for beyond IMT-Advanced such as Coordinated multi-point systems (CoMP), Network Coding, Device-to-Device and Spectrum Sharing Contains key information for researchers from academia and industry, engineers, regulators and decision makers working on LTE-Advanced and beyond
Nature Inspired Algorithms And Applied Optimization
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Author : Xin-She Yang
language : en
Publisher: Springer
Release Date : 2017-10-08
Nature Inspired Algorithms And Applied Optimization written by Xin-She Yang and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-10-08 with Technology & Engineering categories.
This book reviews the state-of-the-art developments in nature-inspired algorithms and their applications in various disciplines, ranging from feature selection and engineering design optimization to scheduling and vehicle routing. It introduces each algorithm and its implementation with case studies as well as extensive literature reviews, and also includes self-contained chapters featuring theoretical analyses, such as convergence analysis and no-free-lunch theorems so as to provide insights into the current nature-inspired optimization algorithms. Topics include ant colony optimization, the bat algorithm, B-spline curve fitting, cuckoo search, feature selection, economic load dispatch, the firefly algorithm, the flower pollination algorithm, knapsack problem, octonian and quaternion representations, particle swarm optimization, scheduling, wireless networks, vehicle routing with time windows, and maximally different alternatives. This timely book serves as a practical guide and reference resource for students, researchers and professionals.
Cooperative Relay Diversity For Distributed Wireless Networks
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Author : Phee Lep Yeoh
language : en
Publisher:
Release Date : 2012
Cooperative Relay Diversity For Distributed Wireless Networks written by Phee Lep Yeoh and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with Internetworking (Telecommunication) categories.
Cooperative Communications And Networking
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Author : K. J. Ray Liu
language : en
Publisher: Cambridge University Press
Release Date : 2009
Cooperative Communications And Networking written by K. J. Ray Liu and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with Computers categories.
Presents the fundamentals of cooperative communications and networking with a holistic approach to principal topics where improvements can be obtained.
Fourth Generation Wireless Networks Applications And Innovations
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Author : Adibi, Sasan
language : en
Publisher: IGI Global
Release Date : 2009-12-31
Fourth Generation Wireless Networks Applications And Innovations written by Adibi, Sasan and has been published by IGI Global this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009-12-31 with Business & Economics categories.
Fourth-Generation Wireless Networks: Applications and Innovations presents a comprehensive collection of recent findings in access technologies useful in the architecture of wireless networks.
Coherent Cooperative Relaying In Low Mobility Wireless Multiuser Networks
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Author : Stefan Berger
language : en
Publisher: Logos Verlag Berlin GmbH
Release Date : 2010
Coherent Cooperative Relaying In Low Mobility Wireless Multiuser Networks written by Stefan Berger and has been published by Logos Verlag Berlin GmbH this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.
In this thesis, several important aspects of cooperative wireless multiuser networks are investigated. The focus lies on coherent two-hop relaying networks where several amplify-and-forward (AF) relays assist the communication between multiple source-destination pairs. First, the impact of local oscillator (LO) imperfections and I/Q imbalance at the relays on two-hop relaying is investigated. A special focus lies on the comparison between frequency division duplexing (FDD) and time division duplexing (TDD) relays. Based on the observation that the direction in which a channel between two wireless nodes is measured has an impact on the estimate, phase synchronization requirements for coherent relaying networks are then found. Several channel estimation protocols that differ in the direction in which the single-hop channels are measured are furthermore identi'ed and their performance is compared. Next, a very simple phase synchronization scheme is presented that provides a set of relays with a common LO phase. Two coherent beamforming schemes, namely multiuser zero-forcing (MUZF) and multiuser minimum mean squared error (MMSE) relaying, are then investigated. Finally, a real-world demonstrator for distributed wireless communication networks (called RACooN Lab) is presented. It was used to implement coherent cooperative communication schemes on a practical two-hop relaying network.
Quality Of Service And Resource Allocation In Wimax
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Author : Roberto Hincapie
language : en
Publisher: BoD – Books on Demand
Release Date : 2012-02-03
Quality Of Service And Resource Allocation In Wimax written by Roberto Hincapie and has been published by BoD – Books on Demand this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-02-03 with Technology & Engineering categories.
This book has been prepared to present state of the art on WiMAX Technology. It has been constructed with the support of many researchers around the world, working on resource allocation, quality of service and WiMAX applications. Such many different works on WiMAX, show the great worldwide importance of WiMAX as a wireless broadband access technology. This book is intended for readers interested in resource allocation and quality of service in wireless environments, which is known to be a complex problem. All chapters include both theoretical and technical information, which provides an in depth review of the most recent advances in the field for engineers and researchers, and other readers interested in WiMAX.