Download or read book Multiuser MIMO Systems in Single cell and Multi cell Wireless Communication written by Runhua Chen and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Power Control for Multi Cell Massive MIMO written by Amin Ghazanfari and published by Linköping University Electronic Press. This book was released on 2019-10-07 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cellular network operators have witnessed significant growth in data traffic in the past few decades. This growth occurs due to the increases in the number of connected mobile devices, and further, the emerging mobile applications developed for rendering video-based on-demand services. As the frequency bandwidth for cellular communication is limited, significant effort was dedicated to improve the utilization of the available spectrum and increase the system performance via new technologies. For example, 3G and 4G networks were designed to facilitate high data traffic in cellular networks in past decades. Nevertheless, there is a necessity for new cellular network technologies to accommodate the ever-growing data traffic demand. 5G is behind the corner to deal with the tremendous data traffic requirements that will appear in cellular networks in the next decade. Massive MIMO (multiple-input-multi-output) is one of the backbone technologies in 5G networks. Massive MIMO originated from the concept of multi-user MIMO. It consists of base stations (BSs) implemented with a large number of antennas to increase the signal strengths via adaptive beamforming and concurrently serving many users on the same time-frequency blocks. As an outcome of using Massive MIMO technology, there is a notable enhancement of both sum spectral efficiency (SE) and energy efficiency (EE) in comparison with conventional MIMO based cellular networks. Resource allocation is an imperative factor to exploit the specified gains of Massive MIMO. It corresponds to properly allocating resources in the time, frequency, space, and power domains for cellular communication. Power control is one of the resource allocation methods to deliver high spectral and energy efficiency of Massive MIMO networks. Power control refers to a scheme that allocates transmit powers to the data transmitters such that the system maximizes some desirable performance metric. In the first part of this thesis, we investigate reusing the resources of a Massive MIMO system, for direct communication of some specific user pairs known as device-to-device (D2D) underlay communication. D2D underlay can conceivably increase the SE of traditional Massive MIMO systems by enabling more simultaneous transmissions on the same frequencies. Nevertheless, it adds additional mutual interference to the network. Consequently, power control is even more essential in this scenario in comparison with conventional Massive MIMO systems to limit the interference that is caused between the cellular network and the D2D communication, thereby enabling their coexistence. In this part, we propose a novel pilot transmission scheme for D2D users to limit the interference to the channel estimation phase of cellular users in comparison with the case of sharing pilot sequences for cellular and D2D users. We also introduce a novel pilot and data power control scheme for D2D underlaid Massive MIMO systems. This method aims at assuring that D2D communication enhances the SE of the network in comparison with conventional Massive MIMO systems. In the second part of this thesis, we propose a novel power control approach for multi-cell Massive MIMO systems. The new power control approach solves the scalability issue of two well-known power control schemes frequently used in the Massive MIMO literature, which are based on the network-wide max-min and proportional fairness performance metrics. We first explain the scalability issue of these existing approaches. Additionally, we provide mathematical proof for the scalability of our proposed method. Our scheme aims at maximizing the geometric mean of the per-cell max-min SE. To solve this optimization problem, we prove that it can be rewritten in a convex form and then be solved using standard optimization solvers.

Download or read book MIMO Wireless Networks written by Bruno Clerckx and published by Academic Press. This book was released on 2013-01-23 with total page 773 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is unique in presenting channels, techniques and standards for the next generation of MIMO wireless networks. Through a unified framework, it emphasizes how propagation mechanisms impact the system performance under realistic power constraints. Combining a solid mathematical analysis with a physical and intuitive approach to space-time signal processing, the book progressively derives innovative designs for space-time coding and precoding as well as multi-user and multi-cell techniques, taking into consideration that MIMO channels are often far from ideal.Reflecting developments since the first edition was published, this book has been thoroughly revised, and now includes new sections and five new chapters, respectively dealing with receiver design, multi-user MIMO, multi-cell MIMO, MIMO implementation in standards, and MIMO system-level evaluation. Extended introduction to multi-dimensional propagation, including polarization aspects Detailed and comparative description of physical models and analytical representations of single- and multi-link MIMO channels, covering the latest standardized models Thorough overview of space-time coding techniques, covering both classical and more recent schemes under information theory and error probability perspectives Intuitive illustration of how real-world propagation affects the capacity and the error performance of MIMO transmission schemes Detailed information theoretic analysis of multiple access, broadcast and interference channels In-depth presentation of multi-user diversity, resource allocation and (non-)linear MU-MIMO precoding techniques with perfect and imperfect channel knowledge Extensive coverage of cooperative multi-cell MIMO-OFDMA networks, including network resource allocation optimization, coordinated scheduling, beamforming and power control, interference alignment, joint processing, massive and network MIMO Applications of MIMO and Coordinated Multi-Point (CoMP) in LTE, LTE-A and WiMAX Theoretical derivations and results contrasted with practical system level evaluations highlighting the performance of single- and multi-cell MIMO techniques in realistic deployments

Download or read book Recent Trends in Multi user MIMO Communications written by Maha Ben Zid and published by BoD – Books on Demand. This book was released on 2013-12-04 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book emphasis on multi-user MIMO communication. It covers a collection of the major topics and issues in multi-user MIMO systems. Recent Trends in Multi-user MIMO Communications provides a tutorial overview of the latest technologies and research keys related to multi-user communication. This book is composed of seven chapters, each written by a different set of authors. Features include: Fundamentals of multi-user MIMO communication, Random Beamforming in multi-user MIMO systems, LTE and LTE-Advanced framework, Interference cancellation in multi-user MIMO systems, Incorporation of multi-user capabilities in IEEE 802.11n/ac for WLAN systems, Physical layer security for multi-user MIMO communication, User selection based error probability of MIMO detector in multi-user MIMO systems.

Download or read book Fundamentals of Massive MIMO written by Thomas L. Marzetta and published by Cambridge University Press. This book was released on 2016-11-17 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first complete guide to the physical and engineering principles of Massive MIMO, written by the pioneers of the concept.

Download or read book MIMO Wireless Communications written by Claude Oestges and published by Academic Press. This book was released on 2010-07-27 with total page 477 pages. Available in PDF, EPUB and Kindle. Book excerpt: Uniquely, this book proposes robust space-time code designs for real-world wireless channels. Through a unified framework, it emphasizes how propagation mechanisms such as space-time frequency correlations and coherent components impact the MIMO system performance under realistic power constraints. Combining a solid mathematical analysis with a physical and intuitive approach to space-time coding, the book progressively derives innovative designs, taking into consideration that MIMO channels are often far from ideal.The various chapters of this book provide an essential, complete and refreshing insight into the performance behaviour of space-time codes in realistic scenarios and constitute an ideal source of the latest developments in MIMO propagation and space-time coding for researchers, R&D engineers and graduate students.Features include• Physical models and analytical representations of MIMO propagation channels, highlighting the strengths and weaknesses of various models• Overview of space-time coding techniques, covering both classical and more recent schemes under information theory and error probability perspectives• In-depth presentation of how real-world propagation affects the capacity and the error performance of MIMO transmission schemes• Innovative and practical designs of robust space-time coding, precoding and antenna selection techniques for realistic propagation (including single-carrier and MIMO-OFDM transmissions)"This book offers important insights into how space-time coding can be tailored for real-world MIMO channels. The discussion of MIMO propagation models is also intuitive and well-developed."Arogyaswami J. Paulraj, Professor, Stanford University, CA"Finally a book devoted to MIMO from a new perspective that bridges the boundaries between propagation, channel modeling, signal processing and space-time coding. It is of high reference value, combining intuitive and conceptual explanations with detailed, stringent derivations of basic facts of MIMO." Ernst Bonek, Emeritus Professor, Technische Universität Wien, Austria * Presents space-time coding techniques for real-world MIMO channels* Contains new design methodologies and criteria that guarantee the robustness of space-time coding in real life wireless communications applications* Evaluates the performance of space-time coding in real world conditions

Download or read book Resource Allocation for Max Min Fairness in Multi Cell Massive MIMO written by Trinh van Chien and published by Linköping University Electronic Press. This book was released on 2018-01-11 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Massive MIMO (multiple-input multiple-output) is considered as an heir of the multi-user MIMO technology and it has recently gained lots of attention from both academia and industry. By equipping base stations (BSs) with hundreds of antennas, this new technology can provide very large multiplexing gains by serving many users on the same time-frequency resources and thereby bring significant improvements in spectral efficiency (SE) and energy efficiency (EE) over the current wireless networks. The transmit power, pilot training, and spatial transmission resources need to be allocated properly to the users to achieve the highest possible performance. This is called resource allocation and can be formulated as design utility optimization problems. If the resource allocation in Massive MIMO is optimized, the technology can handle the exponential growth in both wireless data traffic and number of wireless devices, which cannot be done by the current cellular network technology. In this thesis, we focus on two resource allocation aspects in Massive MIMO: The first part of the thesis studies if power control and advanced coordinated multipoint (CoMP) techniques are able to bring substantial gains to multi-cell Massive MIMO systems compared to the systems without using CoMP. More specifically, we consider a network topology with no cell boundary where the BSs can collaborate to serve the users in the considered coverage area. We focus on a downlink (DL) scenario in which each BS transmits different data signals to each user. This scenario does not require phase synchronization between BSs and therefore has the same backhaul requirements as conventional Massive MIMO systems, where each user is preassigned to only one BS. The scenario where all BSs are phase synchronized to send the same data is also included for comparison. We solve a total transmit power minimization problem in order to observe how much power Massive MIMO BSs consume to provide the requested quality of service (QoS) of each user. A max-min fairness optimization is also solved to provide every user with the same maximum QoS regardless of the propagation conditions. The second part of the thesis considers a joint pilot design and uplink (UL) power control problem in multi-cell Massive MIMO. The main motivation for this work is that the pilot assignment and pilot power allocation is momentous in Massive MIMO since the BSs are supposed to construct linear detection and precoding vectors from the channel estimates. Pilot contamination between pilot-sharing users leads to more interference during data transmission. The pilot design is more difficult if the pilot signals are reused frequently in space, as in Massive MIMO, which leads to greater pilot contamination effects. Related works have only studied either the pilot assignment or the pilot power control, but not the joint optimization. Furthermore, the pilot assignment is usually formulated as a combinatorial problem leading to prohibitive computational complexity. Therefore, in the second part of this thesis, a new pilot design is proposed to overcome such challenges by treating the pilot signals as continuous optimization variables. We use those pilot signals to solve different max-min fairness optimization problems with either ideal hardware or hardware impairments.

Download or read book MIMO Communication for Cellular Networks written by Howard Huang and published by Springer Science & Business Media. This book was released on 2011-11-19 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the theoretical foundations of multiple-antenna techniques evolve and as these multiple-input multiple-output (MIMO) techniques become essential for providing high data rates in wireless systems, there is a growing need to understand the performance limits of MIMO in practical networks. To address this need, MIMO Communication for Cellular Networks presents a systematic description of MIMO technology classes and a framework for MIMO system design that takes into account the essential physical-layer features of practical cellular networks. In contrast to works that focus on the theoretical performance of abstract MIMO channels, MIMO Communication for Cellular Networks emphasizes the practical performance of realistic MIMO systems. A unified set of system simulation results highlights relative performance gains of different MIMO techniques and provides insights into how best to use multiple antennas in cellular networks under various conditions. MIMO Communication for Cellular Networks describes single-user, multiuser, network MIMO technologies and system-level aspects of cellular networks, including channel modeling, resource scheduling, interference mitigation, and simulation methodologies. The key concepts are presented with sufficient generality to be applied to a wide range of wireless systems, including those based on cellular standards such as LTE, LTE-Advanced, WiMAX, and WiMAX2. The book is intended for use by graduate students, researchers, and practicing engineers interested in the physical-layer design of state-of-the-art wireless systems.

Download or read book Energy Efficient Pilot Data Power Control in MU MIMO Communication Systems written by Ye Zhang and published by . This book was released on 2018 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiple-input multiple-output (MIMO) antenna system is considered as a core technology for wireless communication. To reap the benefits of MIMO at a greater scale, massive MIMO with very large antenna arrays deployed at base station (BS) has recently become the forefront in wireless communication research. Till present, the design and analysis of large-scale MIMO systems is a fairly new subject. On the other hand, excessive power usage in MIMO networks is a crucial issue for mobile operators and the explosive growth of wireless services contributes largely to the worldwide carbon footprint. As such, significant efforts have been devoted to improve the spectral efficiency (SE) as well as energy efficiency (EE) of MIMO communication systems over the past decade, resulting in many energy efficient techniques such as power allocation. This thesis investigates novel energy-efficient pilot-data power control strategies which can be used in both conventional MIMO and massive MIMO communication systems. The new pilot-data power control algorithms are developed based ontwo optimization frameworks: one aims to minimize the total transmit power while satisfying per-user signal-interference-plus-noise ratio (SINR) and power constraints; the other aims to maximize the total EE, which is defined as the ratio of the total SE to the transmit power, under individual user power constraints. The proposed novel pilot-data power allocation schemes also take into account the maximum-ratio combining (MRC) and zero-forcing (ZF) detectors in the uplink together with maximum-ratio transmission (MRT) and ZF precoder in the downlink. Considering that a direct use of such SINR expressions in the power control schemeswould lead to a very difficult optimization problem which is not mathematically tractable, we first investigatethe statistical SINR lower bounds for multi-cell multi-user MIMO (MU-MIMO)communication systemsunder minimum mean square error (MMSE) channel estimation. These lower bounds of the per-user average SINRs are used to replace the true SINRs to simplify the power allocation optimization problems. Such relaxation of the original average SINR yields a simplified problem and leads to a suboptimal solution. Then, based on the derived average SINR lower bounds, two novel energy efficient pilot-data power control problems are formulatedwithin the first optimization framework,aiming to minimize the total transmit power budget subject to the per-user SINR requirement and power consumption constraint in multi-cell MU-MIMO systems. For the EE-optimal power allocation problems with MRT precoder and MRC detector, it is revealed that such minimization problems can be converted to a standard geometric programming (GP) procedure which can be further converted to a convex optimization problem. For the pilot-data power control scheme with ZF precoder and ZF detector, geometric inequality is used to approximate the original non-convex optimization to GP problem. The very large number of BS station situation is also discussed by assuming infinite antennas at BS. Numerical results validate the tightness of the derived SINR lower bounds and the advantages of the proposed energy efficient power allocation schemes. Next, two pilot and data power control schemes are developed based on the second power allocation optimization framework to jointly maximize the total EE for both uplink and downlink transmissions in multi-cell MU-MIMO systems under per-user and BS power constraints. The original power control problems are simplified to equivalent convex problems based on the derived SINR lower bounds along with the Dinkelbach's method and the FrankWolfe (FW) iteration. By assuming infinite antennas at BS, the pilot-data power control in massive MIMO case is also discussed. The performance of the proposed pilot-data power allocation schemes based on the two frameworks, namely total transmit power minimization and total EE maximization, are evaluated and compared with the SE maximization scheme. Furthermore, we investigate the pilot-data power allocation for EE communications in single-cell MU-MIMO systems with circuit power consumption in consideration. The pilot and data power allocation schemes are proposed to minimize the total weighted uplink and downlink transmit power as well as processing circuit power consumption while meeting the per-user SINR and BS power consumption constraints. In our proposed schemes, both fixed and flexible numbers of BS antennas are investigated. For the fixed number of BS antennas case, the non-convex optimization problems are converted to a general GP problem to facilitate the solution. An iterative algorithm is proposed to solve the EE-optimal power control problems in the flexible number of BS antennas casebased on the partial convexity of both the cost function and the constraints. It is shown that the convergence of the proposed iterative algorithm is guaranteed due to the fact that each iteration follows convex optimization.

Download or read book Performance Evaluation of Low complexity Multi cell Multi user MIMO Systems written by Jun Zhu and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The idea of utilizing multiple antennas (MIMO) has emerged as one of the significant breakthroughs in modern wireless communications. MIMO techniques canimprove the spectral efficiency of wireless systems and provide significant throughputgains. As such, MIMO will be increasingly deployed in future wireless systems. Onthe other hand, in order to meet the increasing demand for high data rate multimediawireless services, future wireless systems are evolving towards universal frequencyreuse, where neighboring cells may utilize the same radio spectrum. As such, the performanceof future wireless systems will be mainly limited by inter-cell interference(ICI). It has been shown that the throughput gains promised by conventional MIMOtechniques degrade severely in multi-cell systems. This definitely attributes to theexistence of the ICI. A lot of related work has been performed on the ICI mitigation or cancellationstrategies, in multi-cell MIMO systems. Most of them assume that the channel andeven data information is available at the collaborating base stations (BSs). Differentfrom the previous work, we are looking into certain low-complexity codebook-basedmulti-cell multi-user MIMO strategies. For most of our work, we derive the statisticsof the selected user's signal-to-interference-and-noise-ratio (SINR), which enable us tocalculate the achieved sum-rate accurately and e ciently. With the derived sum-rateexpressions, we evaluate and compare the sum-rate performance for several proposedlow-complexity ICI-mitigation systems with various system parameters for single-userper-cell scheduling case. Furthermore, in order to fully exploit spatial multiplexing gain, we are consideringmulti-user per-cell scheduling case. Based on the assumption that all CSI includingintra-cell and inter-cell channels are available at each BS, we rstly look into the centralizedoptimization approach. Typically, since the sum-rate maximization problemis mostly non-convex, it is generally di cult to obtain the globally optimum solution. Through certain approximation and relaxations, we successfully investigate aniterative optimization algorithm which exploits the second-order cone programming(SOCP) approach. From the simulation results, we will observe that the iterativeoption can provide near-optimum sum capacity, although only locally optimized. Afterwards, inspired by the successful application of Per-User Unitary Rate Control(PU2RC) scheme, we manage to extend it into dual-cell environment, with limitedcoordination between two cells.

Download or read book Precoding for Multiuser MIMO Systems with Multiple Base Stations written by Imad Azzam and published by . This book was released on 2008 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Future cellular networks are expected to support extremely high data rates and user capacities. This thesis investigates the downlink of a wireless cellular system that takes advantage of multiple antennas at base stations and mobile stations, frequency reuse across all cells, and cooperation among base stations. We identify asynchronous interference resulting from multi-cell communication as a key challenge, prove the existence of a downlink/uplink duality in that case, and present a linear precoding scheme that exploits this duality. Since this result is not directly extendable to orthogonal frequency division multiplexing (OFDM), we propose a 'hybrid' algorithm for two cooperating base stations, which combines linear and nonlinear precoding. This algorithm minimizes the sum mean squared error of the system and is extendable to OFDM. Finally, we consider the problem of user selection for multiuser precoding in OFDM-based systems. We extend an available single-cell user selection scheme to multiple cooperating cells.

Download or read book Distributed MIMO and Cell Free Mobile Communication written by Xiaohu You and published by Springer Nature. This book was released on 2020-12-21 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: Distributed MIMO and cell-free mobile communication are emerging technologies of wireless communication. This book introduces the fundamental theory, key technology and the prototype system of distributed MIMO and cellular free mobile communication system, including the unified system model, capacity and spectral efficiency analysis under imperfect channel information, cell edge effect, optimal power allocation and energy efficiency optimization, cache optimization, low complexity wireless transmission technology and new network assisted full duplex technology. In addition, the implementation of software and hardware and test results of distributed MIMO and cell free system based on cloud architecture are introduced in detail.This book will benefit senior undergraduates, postgraduates, scholars and engineers who are engaged in wireless mobile communication research. It can also be used as a reference book for postgraduates and researchers in the field of electronic and information engineering.

Download or read book MIMO System Technology for Wireless Communications written by George Tsoulos and published by CRC Press. This book was released on 2018-10-03 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: For broadband communications, it was frequency division multiplexing. For optical communications, it was wavelength division multiplexing. Then, for all types of networks it was code division. Breakthroughs in transmission speed were made possible by these developments, heralding next-generation networks of increasing capability in each case. The basic idea is the same: more channels equals higher throughput. For wireless communications, it is space-time coding using multiple-input-multiple-output (MIMO) technology. Providing a complete treatment of MIMO under a single cover, MIMO System Technology for Wireless Communications assembles coverage on all aspects of MIMO technology along with up-to-date information on key related issues. Contributors from leading academic and industrial institutions around the world share their expertise and lend the book a global perspective. They lead you gradually from basic to more advanced concepts, from propagation modeling and performance analysis to space-time codes, various systems, implementation options and limitations, practical system development considerations, field trials, and network planning issues. Linking theoretical analysis to practical issues, the book does not limit itself to any specific standardization or research/industrial initiatives. MIMO is the catalyst for the next revolution in wireless systems, and MIMO System Technology for Wireless Communications lays a thorough and complete foundation on which to build the next and future generations of wireless networks.

Download or read book Wireless Communications 3rd Edition written by Andreas F. Molisch and published by John Wiley & Sons. This book was released on 2022-12-06 with total page 1014 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Wireless communications is one of the most important modern technologies and is interwoven with all aspects of our daily lives. When we wake up, we check social media, email, and news on our smartphones. Before getting up, we adjust the room temperature through a Bluetooth-connected thermostat. After we leave the house and activate the Wi-Fi security cameras, we order a rideshare on a phone app that recognizes our location and are driven to a factory where manufacturing robots are connected and controlled via 5G. And that is only the start of the day.... It is thus no wonder that wireless infrastructure, user devices, and networks are among the largest and most critical industries in most countries. As the demands for wireless services constantly increase, so are the requirements for new products, and for engineers that can develop these products and bring them to market. Such engineers need a deep understanding of both the fundamentals that govern the behavior of wireless systems, the current standardized systems implementations, and more recent research developments that will influence the next generation of products. The goal of this book is to help students, researchers, and practicing engineers to acquire, refresh, or update this knowledge. It is designed to lead them from the fundamental principles and building blocks, such as digital modulation, fading, and reuse of spectrum, to more advanced technologies that underly modern wireless systems, such as multicarrier and multiantenna transmission, to a description of the standardized systems dominating 5G cellular, Wi-Fi, and short-range communications, to the cutting-edge research that will form the basis for beyond-5G systems. In brief, the book leads the reader from the fundamentals to beyond 5G"--

Download or read book New Directions in Wireless Communications Systems written by Athanasios G. Kanatas and published by CRC Press. This book was released on 2017-10-16 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: Beyond 2020, wireless communication systems will have to support more than 1,000 times the traffic volume of today's systems. This extremely high traffic load is a major issue faced by 5G designers and researchers. This challenge will be met by a combination of parallel techniques that will use more spectrum more flexibly, realize higher spectral efficiency, and densify cells. Novel techniques and paradigms must be developed to meet these goals. The book addresses diverse key-point issues of next-generation wireless communications systems and identifies promising solutions. The book's core is concentrated to techniques and methods belonging to what is generally called radio access network.

Download or read book Massive MIMO written by Hien Quoc Ngo and published by Linköping University Electronic Press. This book was released on 2015-01-16 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: The last ten years have seen a massive growth in the number of connected wireless devices. Billions of devices are connected and managed by wireless networks. At the same time, each device needs a high throughput to support applications such as voice, real-time video, movies, and games. Demands for wireless throughput and the number of wireless devices will always increase. In addition, there is a growing concern about energy consumption of wireless communication systems. Thus, future wireless systems have to satisfy three main requirements: i) having a high throughput; ii) simultaneously serving many users; and iii) having less energy consumption. Massive multiple-input multiple-output (MIMO) technology, where a base station (BS) equipped with very large number of antennas (collocated or distributed) serves many users in the same time-frequency resource, can meet the above requirements, and hence, it is a promising candidate technology for next generations of wireless systems. With massive antenna arrays at the BS, for most propagation environments, the channels become favorable, i.e., the channel vectors between the users and the BS are (nearly) pairwisely orthogonal, and hence, linear processing is nearly optimal. A huge throughput and energy efficiency can be achieved due to the multiplexing gain and the array gain. In particular, with a simple power control scheme, Massive MIMO can offer uniformly good service for all users. In this dissertation, we focus on the performance of Massive MIMO. The dissertation consists of two main parts: fundamentals and system designs of Massive MIMO. In the first part, we focus on fundamental limits of the system performance under practical constraints such as low complexity processing, limited length of each coherence interval, intercell interference, and finite-dimensional channels. We first study the potential for power savings of the Massive MIMO uplink with maximum-ratio combining (MRC), zero-forcing, and minimum mean-square error receivers, under perfect and imperfect channels. The energy and spectral efficiency tradeoff is investigated. Secondly, we consider a physical channel model where the angular domain is divided into a finite number of distinct directions. A lower bound on the capacity is derived, and the effect of pilot contamination in this finite-dimensional channel model is analyzed. Finally, some aspects of favorable propagation in Massive MIMO under Rayleigh fading and line-of-sight (LoS) channels are investigated. We show that both Rayleigh fading and LoS environments offer favorable propagation. In the second part, based on the fundamental analysis in the first part, we propose some system designs for Massive MIMO. The acquisition of channel state information (CSI) is very importantin Massive MIMO. Typically, the channels are estimated at the BS through uplink training. Owing to the limited length of the coherence interval, the system performance is limited by pilot contamination. To reduce the pilot contamination effect, we propose an eigenvalue-decomposition-based scheme to estimate the channel directly from the received data. The proposed scheme results in better performance compared with the conventional training schemes due to the reduced pilot contamination. Another important issue of CSI acquisition in Massive MIMO is how to acquire CSI at the users. To address this issue, we propose two channel estimation schemes at the users: i) a downlink "beamforming training" scheme, and ii) a method for blind estimation of the effective downlink channel gains. In both schemes, the channel estimation overhead is independent of the number of BS antennas. We also derive the optimal pilot and data powers as well as the training duration allocation to maximize the sum spectral efficiency of the Massive MIMO uplink with MRC receivers, for a given total energy budget spent in a coherence interval. Finally, applications of Massive MIMO in relay channels are proposed and analyzed. Specifically, we consider multipair relaying systems where many sources simultaneously communicate with many destinations in the same time-frequency resource with the help of a massive MIMO relay. A massive MIMO relay is equipped with many collocated or distributed antennas. We consider different duplexing modes (full-duplex and half-duplex) and different relaying protocols (amplify-and-forward, decode-and-forward, two-way relaying, and one-way relaying) at the relay. The potential benefits of massive MIMO technology in these relaying systems are explored in terms of spectral efficiency and power efficiency.

Download or read book MIMO Wireless Communications written by Ezio Biglieri and published by Cambridge University Press. This book was released on 2007-01-08 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiple-input multiple-output (MIMO) technology constitutes a breakthrough in the design of wireless communications systems, and is already at the core of several wireless standards. Exploiting multipath scattering, MIMO techniques deliver significant performance enhancements in terms of data transmission rate and interference reduction. This 2007 book is a detailed introduction to the analysis and design of MIMO wireless systems. Beginning with an overview of MIMO technology, the authors then examine the fundamental capacity limits of MIMO systems. Transmitter design, including precoding and space-time coding, is then treated in depth, and the book closes with two chapters devoted to receiver design. Written by a team of leading experts, the book blends theoretical analysis with physical insights, and highlights a range of key design challenges. It can be used as a textbook for advanced courses on wireless communications, and will also appeal to researchers and practitioners working on MIMO wireless systems.