Coherent Cooperative Relaying In Low Mobility Wireless Multiuser Networks
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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.
Localization And Posture Recognition Via Magneto Inductive And Relay Aided Sensor Networks
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Author : Henry Ruben Lucas Schulten
language : en
Publisher: Logos Verlag Berlin GmbH
Release Date : 2022-12-15
Localization And Posture Recognition Via Magneto Inductive And Relay Aided Sensor Networks written by Henry Ruben Lucas Schulten 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 2022-12-15 with Technology & Engineering categories.
Body-centric wireless sensor networks are expected to enable future technologies such as medical in-body micro robots or unobtrusive smart textiles. These technologies may advance personalized healthcare as they allow for tasks such as minimally invasive surgery, in-body diagnosis, and continuous activity recognition. However, the localization of individual sensor nodes within such networks or the determination of the entire network topology still pose challenges that need to be solved. This work provides both theoretic and simulative insights to enable the required sub-millimeter localization accuracy of such sensors using magneto-inductive networks. It identifies inherent localization issues such as the asymmetry of the position estimation in magneto-inductive networks and outlines how such issues may be addressed by using passive relays or cooperation. It further proposes a novel approach to recognize the entire structure of a magneto-inductive network using simple impedance measurements and clusters of passive tags. This approach is evaluated extensively by simulation and experiment to demonstrate the feasibility of low-cost human body posture recognition.
Magneto Inductive Communication And Localization
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Author : Gregor Dumphart
language : en
Publisher: Logos Verlag Berlin GmbH
Release Date : 2022-06-15
Magneto Inductive Communication And Localization written by Gregor Dumphart 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 2022-06-15 with Technology & Engineering categories.
Utilizing magnetic induction for wireless communication, wireless powering, passive relaying, and localization could enable massive wireless sensor applications with tiny nodes in challenging media, foremost biomedical in-body sensor networks. This work investigates the performance limits of these unique wireless systems with hardly any assumptions. As a foundation, a general system model and an interface to communication theory are developed. A major part of this work identifies two crucial magneto-inductive fading channels: that between randomly oriented coils and that caused by a nearby swarm of resonant passive relay coils. The analysis yields important technological implications. Based thereon, an investigation of wirelessly-powered in-body sensors is conducted, revealing their active and passive data transmission capabilities. Finally, a treatise of magneto-inductive node localization develops algorithms that perform near identified accuracy limits in theory and practice.
Affordable Nonlinear Mimo Systems
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Author : Georgios Psaltopoulos
language : en
Publisher: Logos Verlag Berlin GmbH
Release Date : 2011
Affordable Nonlinear Mimo Systems written by Georgios Psaltopoulos 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 2011 with Technology & Engineering categories.
Cooperative Relaying And Adaptive Scheduling For Low Mobility Wireless Access Networks
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Author : Ingmar Hammerström
language : en
Publisher:
Release Date : 2006
Cooperative Relaying And Adaptive Scheduling For Low Mobility Wireless Access Networks written by Ingmar Hammerström and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with categories.
Cooperative Relaying And Its Application
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Author : Stefan Valentin
language : en
Publisher: Sudwestdeutscher Verlag Fur Hochschulschriften AG
Release Date : 2010-10
Cooperative Relaying And Its Application written by Stefan Valentin and has been published by Sudwestdeutscher Verlag Fur Hochschulschriften AG this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010-10 with categories.
Cooperative relaying is a promising approach to improve data rate and coverage in wireless networks. Although the benefits of cooperation have been consistently shown in theory, the performance of realistic cooperative networks is still not clear. Bridging this gap between theory and practice is the objective of this thesis. This is done in three steps. First, practical selection relaying protocols are analyzed under realistic assumptions. Second, efficient protocol extensions are described and, third, a prototype for cooperative Wireless Local Area Networks (WLANs) is demonstrated. Based on theoretical findings and extensive field measurements, this thesis provides insight into the performance regions of realistic cooperative networks and into implementing cooperative devices. Furthermore, the basic elements of cooperative systems are introduced and a concise taxonomy of common designs is given. This text is, thus, helpful for researchers and engineers who implement cooperative systems, plan to support their networks by relaying, or look for an introduction in the field.
Wideband Multi User Cooperative Networks
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Author : Etienne Auger
language : en
Publisher: Logos Verlag Berlin GmbH
Release Date : 2012
Wideband Multi User Cooperative Networks written by Etienne Auger 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 2012 with Computers categories.
This book details promising communication schemes and channel modeling for a pervasive wireless access network (PWAN). Such a network is formed by nodes equipped with heterogeneous antenna arrangements and placed up to 10 m apart from each other. Nodes can be static when they belong to the infrastructure or have limited mobility when they are carried by a person. This scenario is extremely interesting for relay-based applications and fills the gap between the body area network that has a coverage up to 1 m and the wireless local area network that has a coverage up to 100 m. When a PWAN is jointly considered with high node density, it allows for node cooperations, and idle or infrastructure nodes can support the communication of source-destination pairs. With an adequate signaling scheme, the PWAN can operate as a virtual antenna array and ultimately achieve multiple-input multiple-output (MIMO) gains in a distributed way. Until now these networks have been studied using oversimplified channel models that were frequency flat and designed for cellular low node density networks. The novelty of this book is the study of a PWAN under realistic channel conditions and hardware constraints.
Multiuser Wireless Networks
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Author : Lifeng Lai
language : en
Publisher:
Release Date : 2007
Multiuser Wireless Networks written by Lifeng Lai and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with Computer networks categories.
Abstract: The presence of multiple users in the wireless network offers users with an opportunity to cooperate. Adopting tools from network information theory, this thesis investigates the utilities of user cooperation under various scenarios and examines the validity of cooperation assumption in energy limited networks. We first consider the construction of cooperation strategies for a wireless network composed of three nodes and limited by half-duplex and total power constraints. We show that noisy feedback plays a crucial role in devising efficient cooperation schemes for various channels. For the relay channel, we propose a new cooperation scheme that exploits the wireless feedback gain. Our analysis of the achievable rate of this scheme reveals the diminishing feedback gain at both the low and high signal-to-noise ratio regimes. Inspired by the proposed feedback strategy, we identify a greedy cooperation framework applicable to both the multicast and three-way channels. Our performance analysis reveals the asymptotic optimality of the proposed greedy approach in the wireless network setting. We then establish the utility of user cooperation in facilitating secure wireless communications. In particular, the four-terminal relay-eavesdropper channel is introduced and an outer-bound on the optimal rate-equivocation region is derived. Several cooperation strategies are then devised and the corresponding achievable rate-equivocation regions are characterized. The gain offered by the proposed cooperation strategies is then proved theoretically and validated numerically in the Additive White Gaussian Noise channel. We also examine user cooperation from game theoretic perspective. Using game theoretic framework, the critical role of altruistic nodes in encouraging cooperation is established, both for small and large scale networks. In a small network, where nodes utilize decode-and-forward scheme to cooperate, we show that a relay node, with appropriate strategy and location, successfully turns the Nash Equilibrium from no-cooperation to full-cooperation. In the large scale network, we show that it is sufficient to have a vanishingly small fraction of the nodes to be altruistic, i.e., relay nodes, in order to ensure full cooperation from all the nodes in the network.
Link Adaptation For Relay Based Cellular Networks
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Author : Basak Can
language : en
Publisher: CRC Press
Release Date : 2022-09-01
Link Adaptation For Relay Based Cellular Networks written by Basak Can and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022-09-01 with Technology & Engineering categories.
Cover TextLink Adaptation for Relay-Based Cellular Networks focuses on the implementation of various link adaptation methods in OFDM(A) (Orthogonal Frequency Division Multiplexing/Multiple Access)?Time Division Duplex (TDD) based two-hop cellular networks. The analysis and design consider infrastructure based relays. New link adaptive transmission methods which dynamically select the channel coding, modulation, forwarding, relaying mechanisms and the packet size have been designed and evaluated for such networks. The selection among various schemes is based on maximizing the end-to-end throughput.This book provides a channel adaptive scheduler which considers the multiplexing loss caused by the two-phase nature of wireless relaying. The scheduler dynamically schedules the users on the frequency-time radio resources with efficient Modulation and Coding Schemes (MCS)s selected by Adaptive Modulation and Coding (AMC). Relaying is used only if it can provide throughput enhancement. The guidelines for efficient deployment of infrastructure based relay terminals are given. For the two-hop cellular communication systems, the system level performance of various cooperative diversity schemes has been investigated with the scheduler developed and the relays efficiently deployed in the cell. This investigation for low mobility scenarios shows that, a simple cooperative diversity scheme that dynamically chooses the best scheme among direct transmission and two-hop conventional relaying is a promising choice when compared to various more complex cooperative diversity schemes.In this book, a hop adaptive Medium Access Control (MAC)-Protocol Data Unit (PDU) size optimization is proposed for wireless relay networks.
Mimo Ofdm For Lte Wifi And Wimax
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Author : Lajos Hanzo
language : en
Publisher: John Wiley & Sons
Release Date : 2010-11-01
Mimo Ofdm For Lte Wifi And Wimax written by Lajos Hanzo 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 2010-11-01 with Technology & Engineering categories.
MIMO-OFDM for LTE, WIFI and WIMAX: Coherent versus Non-Coherent and Cooperative Turbo-Transceivers provides an up-to-date portrayal of wireless transmission based on OFDM techniques augmented with Space-Time Block Codes (STBCs) and Spatial-Division Multiple Access (SDMA). The volume also offers an in-depth treatment of cutting-edge Cooperative Communications. This monograph collates the latest techniques in a number of specific design areas of turbo-detected MIMO-OFDM wireless systems. As a result a wide range of topical subjects are examined, including channel coding and multiuser detection (MUD), with a special emphasis on optimum maximum-likelihood (ML) MUDs, reduced-complexity genetic algorithm aided near-ML MUDs and sphere detection. The benefits of spreading codes as well as joint iterative channel and data estimation are only a few of the radical new features of the book. Also considered are the benefits of turbo and LDPC channel coding, the entire suite of known joint coding and modulation schemes, space-time coding as well as SDM/SDMA MIMOs within the context of various application examples. The book systematically converts the lessons of Shannon's information theory into design principles applicable to practical wireless systems; the depth of discussions increases towards the end of the book. Discusses many state-of-the-art topics important to today's wireless communications engineers. Includes numerous complete system design examples for the industrial practitioner. Offers a detailed portrayal of sphere detection. Based on over twenty years of research into OFDM in the context of various applications, subsequently presenting comprehensive bibliographies.