Multichannel Multiuser And Multiple Antenna Wireless Communication Systems

We also study the design of precoding and decoding matrices for the downlink of a multiuser MIMO system when spatial multiplexing is used. We investigate the block diagonalization approach for multiuser MIMO systems and propose a random precoding technique that schedules users for transmission with only limited feedback from the receivers. We then introduce a new optimization criterion for designing a linear transceiver which tries to minimize the maximum mean-squared error among all users or data substreams; we show that this approach results in fairness among users and improved average BER.

This innovative book sets forth two promising wireless approachesthat support high-quality, high-speed data and multimediaservice-multiple antenna technologies and cross layer transmitteradaptation designs-while highlighting the relationships andinteractions between them. The latest advanced technologies ofchannel adaptation techniques for wireless communication systemswith multiple antennas are thoroughly investigated. The book is divided into three parts, first giving readers a goodfoundation in underlying theory, then exploring applications aswell as advanced topics: * Part 1 examines theoretical aspects of channel adaptation inwireless communications for point-to-point and multi-user systemswith multiple antennas * Part 2 focuses on the applications of the channel-adaptivetechnologies in practical systems such as UMTS * Part 3 delves into topics such as multi-user scheduling forwideband systems, combined queuing theory and information theory,and ad hoc routing Using a hands-on, practical approach, Channel Adaptive Technologiesand Cross Layer Designs for Wireless Systems with Multiple Antennasthoroughly covers detailed design considerations that help readersunderstand how to apply theory to real-world systems. Emphasisthroughout the book is on joint optimization across differentlayers of a communications system based on an integrated approach.Examples of popular wireless systems, such as TDMA, wideband CDMA(UMTS), and HSDPA, are used throughout as practical illustrations.Each chapter ends with a summary that reviews key points and a setof problems that lets readers test their knowledge and continue todevelop their skills as they progress to new topics. Figures andtables are also used extensively to help readers visualize complextheory and systems. Combining theory, design, and application into one integratedapproach, this is a superior reference for advanced communicationstheory courses.

Next generation wireless systems will use multiple antenna technologies, also known as multiple-input multiple-output (MIMO), to provide high data rates and robustness against fading. MIMO communication strategies for single user communication systems and their practical application in wireless networks are by now well known. MIMO communication systems, however, can benefit from multiuser processing by coordinating the transmissions to multiple users simultaneously. For numerous reasons, work on the theory of multiuser MIMO communication has yet to see broad adoption in wireless communication standards. For example, global knowledge of channel state information is often required. Such an unrealistic assumption, however, makes it difficult in practice to implement precoding techniques. Furthermore, the achievable rates of the conventional multiuser MIMO techniques are far from the theoretical performance bounds. These and other factors motivate research on practical multiuser communication strategies for the MIMO broadcast channel (point to multi-point communication) and the analysis of those strategies. The primary contributions of this dissertation are i) the development of four novel low complexity coordinated MIMO transceiver design techniques to approach the theoretical performance bound and ii) the investigation of the optimality of the proposed coordinated wireless MIMO networks. Several coordinated beamforming algorithms are proposed, where each mobile station uses quantized combining vectors or each base station uses limited feedback from the MS. The asymptotic optimality of the proposed coordinated beamforming system for the MIMO Gaussian broadcast channel is next investigated. For multi-stream transmission, a novel block diagonalized vector perturbation is proposed and the achievable sum rate upper bound of the proposed system is derived. Finally, for multi-cell environments, linear and non-linear network CBF algorithms supporting multiple cell-boundary users are proposed. The optimality of network coordinated beamforming in terms of the number of receive antennas is also investigated.

Technological progress in the field of wireless communications over the past few years has only been matched by the increasing demand for sophisticated services at lower costs. A significant breakthrough was achieved in the design of efficient wireless communication systems with the advent of the diversity concept. Spatial diversity exploits the availability of multiple spatial paths between the transmitter and receiver by placing antenna arrays at either end. In addition to improving the reliability of communication by creating redundant copies of the transmitted information at the receiver, wireless transceivers with multiple antennas exploit the spatial degrees of freedom to multiplex multiple streams of data and achieve significant gains in spectral efficiencies. In this thesis, we design spatial diversity techniques for slow-fading wireless channels. There are two parts to this thesis: In Part I we propose spatial diversity techniques for point-to-point single-user wireless systems, while in Part II we propose multiuser cooperative diversity techniques for multiuser wireless communication systems.

At present, the expansion of tetherless communications is a technological trend surpassed perhaps only by the explosive growth of the Internet. Wireless systems are being deployed today mainly for telephony, satisfying the ind- trialized nations’ appetite for talk-on-the-go, and providing much-needed communications infrastructure in developing countries. The desire for wi- less access to the Internet is starting to add fuel to the growth of tetherless communications. Indeed, the synergy of wireless and Internet technologies will lead to a host of exciting new applications, some of which are not yet envisioned. Future-generation wireless systems will achieve capacities much higher than the systems of today by incorporating myriad improvements. These in- vations include transmission in higher-frequency bands, “smart antennas”, multi-user detection, new forward error-correction techniques, and advanced network resource-allocation techniques. The term “smart antenna” usually refers to the deployment of multiple antennas at the base-station site, coupled with special processing of the m- tiple received signals. Smart antennas can adaptively reject co-channel int- ference and mitigate multipath fading, and have been identified by many as a promising means to extend base-station coverage, increase system capacity and enhance quality of service.

This book attempts to present exact and approximate analytical solution methods and techniques using queueing theory in the complex multimedia traffic systems with procedures of random multiple access schemes. In particular, this book presents how to approximate the system performance of discrete-time multimedia networks, the probability distribution of the interarrival time of internetwork packets at the adjacent network and the higher moments of the transmission departure distribution and delay in wireless multimedia communication environment. In general the modeling of discrete-time multimedia communication systems are more complex than that of continuous-time systems because multiple state changes can occur from one time-unit to the next. This complicates the analysis of the model. This book also discusses numerical results that illustrate the applications of the theory and various properties.

Competition for limited bandwidth, power, and time resources is an intrinsic aspect of multi-user wireless networks. There has been a recent move towards optimizing coexistence and confidentiality at the physical layer of multi-user wireless networks, mainly by exploiting the advanced capabilities of multiple-input multiple-out (MIMO) signal processing methods. Coexistence of disparate networks is made possible via interference mitigation and suppression, and is exemplified by the current interest in cognitive radio (CR) systems. On the other hand, MIMO communications that are secure at the physical layer without depending upon network-layer encryption are achieved by redirecting jamming or multi-user interference to unauthorized receivers, while minimizing that to legitimate receivers. In all cases, the accuracy of the channel state information (CSI) available at the transmitters plays a crucial role in determining the degree of interference mitigation and confidentiality that is achieved. This dissertation seeks to examine the development of multi-antenna transmission techniques for interference mitigation and/or secure communication in multi-user wireless networks, with emphasis on robust designs for scenarios with imperfect channel state information. Commencing with coexistence in MIMO CR networks, we design novel precoding algorithms for the novel scenario where the CSI of the primary users is completely unknown to the CR, and for a novel network where the primary users coexist with both underlay and spectrum-sensing CRs. The latter half of the thesis considers the secure communication problem in the socalled MIMO wiretap channel with a passive eavesdropper. We first examine the impact of imperfect knowledge of the legitimate channel on the achievable secrecy rate of the MIMO wiretap channel, and design two robust beamforming schemes that are able to recover a large fraction of the secrecy rate lost due to the channel estimation errors. We then consider a more formidable adversary capable of either eavesdropping or jamming in the MIMO wiretap channel. We formulate the interactions between the multi-antenna transmitter and the dual-mode eavesdropper/jammer as a zerosum game with the MIMO ergodic secrecy rate as the payoff function, and deduce the existence and properties of steady-state Nash Equilibria for a variety of gametheoretic scenarios. The culmination of this dissertation is to bring together the coexistence and confidentiality aspects by considering a MIMO cognitive radio network where the CR transmissions serve a dual purpose of jamming the eavesdropper while communicating meaningful information to the underlay receivers, but the CR interference to the primary receiver (PR) must also be limited to a prescribed threshold. When only imperfect CSI is available to the CRs, the primary link security is severely degraded since the CR interference to the PR cannot be effectively controlled, and the jamming signals cannot accurately target the eavesdropper. Therefore, we devise robust CR transmission schemes that reduce the degradation in primary secrecy rate under imperfect CSI.

Antenna diversity has become of critical importance in today's mobile communications systems and this groundbreaking book offers you new approaches to designing transmission strategies for multi-antenna systems. With these novel and practical design strategies you can develop transmission systems that efficiently use available power and bandwidth. The book shows you how to design multi-antenna transceivers in single antenna systems that can reduce transmission power, while ensuring a specified quality level. In addition, you can design wireless networks that have a prescribed degree and probability of connectivity and fault tolerance.