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MIMO Wireless Networks

MIMO Wireless Networks Book
Author : Bruno Clerckx,Claude Oestges
Publisher : Academic Press
Release : 2013-01-23
ISBN : 0123850568
Language : En, Es, Fr & De

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Book Description :

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

Energy Balancing in Wireless Networks with MIMO Communications

Energy Balancing in Wireless Networks with MIMO Communications Book
Author : Hoda Sadat Ayatollahi Tabatabei
Publisher : Unknown
Release : 2018
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

"Wireless networks are vital for supporting a range of applications. With the continuous development of wireless networks, energy conservation and energy efficiency are becoming key factors in improving the network lifetime. In conventional wireless networks, the nodes are equipped with a single antenna, and the energy conservation methods are needed since the nodes have limited capacity and may run out of energy. Although energy harvesting, which provides unlimited amount of energy to the nodes when ambient energy is available, can be helpful in solving this problem, there are times when the energy source is not available. Therefore, implementing energy efficient techniques is essential in wireless networks in order to have energy consumption balance among the wireless nodes. In multi-antenna wireless networks, however, the energy conservation problem can be addressed using the trade-off between the transmit power and the circuit energy consumption. Multiple-Input Multiple-Output (MIMO) communication is a promising approach that can be efficiently used in reducing the energy consumption for communication. In MIMO systems, the transmit power is spread among more than one antenna, which results in having a high power gain and better spectral efficiency. To this end, I propose a system for MIMO wireless networks that optimizes the energy efficiency and provides energy balance by dynamically adjusting the number of antennas based on the nodes' energy levels. Based on the nodes' distance, remaining energy, and the target Bit-Error-Rate (BER), a multi-antenna scheme is chosen for communication on a per-packet basis. The system is modeled using a Markov Decision Process (MDP) and optimized using reinforcement learning. I define the reward function based on the remaining energy, energy consumption, and the distance between the nodes and use Q-learning to find the optimal multi-antenna scheme. In order to extend the idea into a network with more than two nodes, I propose MAC-LEAP: Multi-Antenna, Cross Layer, Energy Adaptive Protocol for single-hop and multi-hop MIMO wireless networks. The protocol selects the most energy efficient MIMO scheme for both the transmitter and the receiver and uses the RTS/CTS hand-shake to transfer some information required by the dynamic antenna selection policy prior to the data transmission. Based on simulation results using the ns-3 network simulator, MAC-LEAP outperforms traditional protocols both in terms of network lifetime and the number of received packets in single hop and multi-hop networks. Moreover, MAC-LEAP is also implemented in a real life animal tracking application called JumboNet. I tested the protocol in three different scenarios; when the nodes have limited energy, when the nodes have unlimited energy, and when the nodes employ energy harvesting. According to the simulation results, MAC-LEAP outperforms the traditional JumboNet network in terms of energy consumption, packet delay, and packet delivery ratio. Moreover, in order to enable network scalability, I propose Cluster-based MIMO (CMIMO), a cluster-based protocol for wireless networks in which the nodes have multiple antennas and are powered either by a non-rechargeable battery or by energy harvesting. In a cluster-based network using MIMO, the nodes are equipped with more than one antenna. CMIMO adjusts the number of antennas for communication between a normal node and a cluster-head in order to improve the energy efficiency of the network. We evaluate CMIMO in two scenarios, a network with wireless nodes with non-rechargeable batteries, and a network with mobile wireless nodes powered with energy harvesting. In both scenarios, the simulation results show that CMIMO outperforms the traditional approach in terms of number of received packets, network lifetime, percentage of dead nodes, and energy consumption."--Pages x-xi.

Interference Management in MIMO Wireless Networks

Interference Management in MIMO Wireless Networks Book
Author : Akbar Ghasemi
Publisher : Unknown
Release : 2013
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

The scarce and overpopulated radio spectrum is going to present a major barrier to the growth and development of future wireless networks. As such, spectrum sharing seems to be inevitable to accommodate the exploding demand for high data rate applications. A major challenge to realizing the potential advantages of spectrum sharing is interference management. This thesis deals with interference management techniques in noncooperative networks.

Interference Management for Multiuser Mimo Wireless Networks

Interference Management for Multiuser Mimo Wireless Networks Book
Author : Tiangao Gou
Publisher : Unknown
Release : 2012
ISBN : 9781267420978
Language : En, Es, Fr & De

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Book Description :

One of the primary goals of designing communication systems is to achieve high data rates. Due to limited spectrum, users need to share the common resource, which causes interference with each other. Interference in turn creates a bottleneck on the communication rate. Recently two breakthroughs have been made to relieve this bottleneck. One is using multiple antennas known as multiple input multiple output (MIMO) technology and the other is an interference management technique called interference alignment. While much progress has been made on understanding of each individually, relatively little is known about how to use both techniques together to deal with interference. This thesis presents the progress we have made towards determining the capacity benefits of multiple antennas and interference alignment in different network settings and under various assumptions about the channel state information known at the transmitters. The thesis consists of five main results. First, we characterize the optimal degrees of freedom (DoF) of the K user MIMO Gaussian interference channel with M transmit and N receive antennas for each user when the ratio of the maximum to the minimum of M and N is equal to an integer. Second, we study the N+1 user single input multiple output (SIMO) Gaussian interference channel with one transmit and N receive antennas for each user. We characterize the generalized degrees of freedom (GDoF) of the network, which directly leads to a capacity approximation within a bounded gap which is independent of the signal strength. We also derive outer bounds which identify a strong interference regime where the capacity region is established. Third, we characterize the optimal DoF of two classes of finite state compound wireless networks including the multiple-input single-output (MISO) finite state compound broadcast channel (BC) with arbitrary number of users and antennas at the transmitter and the finite state scalar (single antenna nodes) compound X networks with arbitrary number of users. Fourth, we propose a blind interference alignment scheme through staggered antenna switching, i.e., we seek to align interference without any knowledge of the channel coefficient values at the transmitters. This scheme achieves the optimal DoF of the vector broadcast channel where the transmitter is equipped with M antennas and there are K receivers, each equipped with a reconfigurable antenna capable of switching among M preset modes. Fifth, we go beyond the single hop wireless networks to multihop interference networks and characterize the DoF of the 2-source 2-destination 2-hop interference network formed by concatenation of two 2-user interference channels. The key to this result is a new idea, called aligned interference neutralization, that provides a way to align interference terms over each hop in a manner that allows them to be cancelled over the air at the last hop.

Towards Gigabit and Green 802 11 Wireless Networks

Towards Gigabit and Green 802 11 Wireless Networks Book
Author : Ioannis Pefkianakis
Publisher : Unknown
Release : 2012
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

Wireless is an increasingly dominant communication medium. The continued quest for wireless connectivity in a multitude of mobile devices, along with the emerging bandwidth hungry applications, has resulted in a huge growth of the wireless traffic. Multiple-Input Multiple-Output (MIMO) is considered the dominant technology to provide gigabit wireless links, and to accommodate the increasing demand of speed over wireless. By using multiple transmit and receive antennas, MIMO can support more reliable and faster communication. But how efficient are the current MIMO systems? Our experiments with commodity MIMO 802.11n devices reveal that, the MIMO wireless is low speed and energy hungry. The fundamental reason for MIMO devices' poor performance the use of legacy 802.11a/b/g, single antenna designs over the multiple antenna, MIMO 802.11n setting. Specifically, the existing designs used over the new MIMO 802.11n devices, are oblivious to MIMO unique communication characteristics. They do not also consider that, MIMO speed comes at the cost of increased power consumption, proportional to the number of antennas. In order to investigate solutions to these problems, this dissertation first experimentally studies the unique features of MIMO wireless and their impact on existing designs' performance. Then, it revises the key mechanisms that control speed and energy over MIMO wireless, named Rate Adaptation, and MIMO Energy Save, and develops three systems. History-Aware Robust Rate Adaptation (HA-RRAA) is our first step towards gigabit wireless. It opportunistically selects the best goodput PHY transmission rate for legacy 802.11a/b/g networks by introducing novel mechanisms to capture short-term channel dynamics. Different from HA-RRAA, our MIMO Rate Adaptation (MiRA) proposal, seeks to identify the best goodput PHY transmission rate in MIMO 802.11n networks by considering the unique features of MIMO. Finally, MIMO Energy Save seeks to select the optimal antenna setting at runtime to minimize energy consumption. Our proposals depart from existing designs in three fundamental ways. They manage the unique MIMO communication modes in a distinct manner. They consider new metrics, to capture the tradeoffs between speed and power consumption. Our proposals also apply novel learning mechanisms to capture the wireless channel dynamics. There are three main contributions in this dissertation. First, it builds a strong connection between wireless communication theory and wireless system design. Specifically, this dissertation provides the first experimental study of fundamental MIMO wireless communication tradeoffs (i.e. diversity vs. spatial multiplexing MIMO modes, speed vs. number of antennas) using 802.11n standard-compliant commodity testbeds. Then, it uncovers their impact on existing designs' performance. Second, it proposes novel and practical rate adaptation and energy save designs that consider MIMO unique characteristics, and are able deliver high performance gains. Third, this dissertation provides the first implementation and evaluation of MIMO rate adaptation and energy save using 802.11n standard-compliant commodity devices. The high performance in real world settings make our proposals a significant step towards gigabit and green wireless networks.

Spectrum Sharing in Wireless Networks

Spectrum Sharing in Wireless Networks Book
Author : John D. Matyjas,Sunil Kumar,Fei Hu
Publisher : CRC Press
Release : 2016-11-17
ISBN : 1498726364
Language : En, Es, Fr & De

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Book Description :

Spectrum Sharing in Wireless Networks: Fairness, Efficiency, and Security provides a broad overview of wireless network spectrum sharing in seven distinct sections: The first section examines the big picture and basic principles, explaining the concepts of spectrum sharing, hardware/software function requirements for efficient sharing, and future trends of sharing strategies. The second section contains more than 10 chapters that discuss differing approaches to efficient spectrum sharing. The authors introduce a new coexistence and sharing scheme for multi-hop networks, describe the space-time sharing concept, introduce LTE-U, and examine sharing in broadcast and unicast environments. They then talk about different cooperation strategies to achieve mutual benefits for primary users (PU) and secondary users (SU), discuss protocols in a spectrum sharing context, and provide different game theory models between PUs and SUs. The third section explains how to model the interactions of PUs and SUs, using an efficient calculation method to determine spectrum availability. Additionally, this section explains how to use scheduling models to achieve efficient SU traffic delivery. The subject of the fourth section is MIMO-oriented design. It focuses on how directional antennas and MIMO antennas greatly enhance wireless network performance. The authors include a few chapters on capacity/rate calculations as well as beamforming issues under MIMO antennas. Power control is covered in the fifth section which also describes the interference-aware power allocation schemes among cognitive radio users and the power control schemes in cognitive radios. The sixth section provides a comprehensive look at security issues, including different types of spectrum sharing attacks and threats as well as corresponding countermeasure schemes. The seventh and final section covers issues pertaining to military applications and examines how the military task protects its data flows when sharing the spectrum with civilian applications.

Communications and Positioning in Wireless Networks

Communications and Positioning in Wireless Networks Book
Author : Yao Zhao,Liang Dong
Publisher : Unknown
Release : 2009
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

My doctoral research for the past three years is presented in this report. My research mainly focuses on the communications and positioning for wireless networks and is composed of three parts. First, I explored a new Turbo frequency equalization technique for multiple-input multiple-output (MIMO) wireless communications systems to improve the performance of wireless communications. In the second part of my research, I studied the multiple antenna cooperative communications from the perspective of information theories. The third part of my work is dedicated to extensive research on positioning technology for wireless networks using knowledge of the estimation theory in signal processing.

Scheduling in Multi user Mimo Wireless Systems

Scheduling in Multi user Mimo Wireless Systems Book
Author : George Maina Mureithi
Publisher : Unknown
Release : 2011
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

It is widely believed that the implementation of multi-user multiple-input multiple- output (MU-MIMO) technology at the radio access portion of current and future wireless networks would positively impact on the performance of such networks. This however demands the design of efficient multi-user scheduling algorithms at the data link layer. One algorithm that is known to be throughput optimal is the opportunistic scheduler. This work takes a cross-layer approach in designing a scheduler that takes into account both the channel and queue states of users. We propose a scheduling algorithm referred to as the Maximum Throughput Scheduler (MTS). The MTS explicitly expresses network throughput as the utility function. Through simulations, we show that the MTS outperforms other schedulers in terms of network throughput.

Optimizing and Testing WLANs

Optimizing and Testing WLANs Book
Author : Tom Alexander
Publisher : Elsevier
Release : 2011-04-01
ISBN : 0080551122
Language : En, Es, Fr & De

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Book Description :

Optimizing and Testing WLANs explores proven techniques for maximizing the coverage area and performance of wireless networks. The author's insider position on the IEEE committee developing standards for WLAN testing ensures timeliness and technical integrity of the material. The book includes coverage of newer multiple input/multiple output (MIMO) wireless networks. The techniques provided will allow engineers to help maintain continuous wireless connectivity to laptops and other mobile devices. Optimizing and Testing WLANs is the first book to address the need to test WLANs (Wireless Local Area Networks) for proper performance and to optimize their operation as they become increasingly common. It covers test equipment and methods for the RF (wireless) and physical layers of WLAN, protocols, the application layer, and manufacturing testing. The emphasis throughout is on underlying engineering principles along with modern metrics and methodologies, ensuring this book gives both a solid theoretical background along with field-proven techniques and applications. A particularly engaging chapter deals with manufacturing test that describes some of the different manufacturing test setups and equipment. A concise introduction to deployment testing of "hotspots" and WLANs in enterprises is also provided. This text will be of interest to RF wireless engineers and designers, networking engineers, IT professionals and managers, and graduate students. *Gives proven techniques for maximizing the coverage area and performance of wireless networks *Author's insider position on the IEEE committee developing standards for WLAN testing ensures timeliness and technical integrity of the material *Includes coverage of newer multiple input/multiple output (MIMO) wireless networks

MIMO System Technology for Wireless Communications

MIMO System Technology for Wireless Communications Book
Author : George Tsoulos
Publisher : CRC Press
Release : 2018-10-03
ISBN : 1420005928
Language : En, Es, Fr & De

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Book Description :

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.

Towards 5G Wireless Networks

Towards 5G Wireless Networks Book
Author : Hossein Khaleghi Bizaki
Publisher : BoD – Books on Demand
Release : 2016-12-14
ISBN : 9535128337
Language : En, Es, Fr & De

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Book Description :

This book intends to provide highlights of the current research topics in the field of 5G and to offer a snapshot of the recent advances and major issues faced today by the researchers in the 5G physical layer perspective. Various aspects of 5G system is deeply discussed (in three parts and ten chapters) with emphasis on its physical layer. Each chapter provides a comprehensive survey of the subject area and ends with a rich list of references to provide an in-depth coverage of the application at hand.

Adaptive Wireless Communications

Adaptive Wireless Communications Book
Author : Daniel W. Bliss,Siddhartan Govindasamy
Publisher : Cambridge University Press
Release : 2013-05-09
ISBN : 1107067731
Language : En, Es, Fr & De

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Book Description :

Adopting a balanced mix of theory, algorithms and practical design issues, this comprehensive volume explores cutting-edge applications in adaptive wireless communications and the implications these techniques have for future wireless network performance. Presenting practical concerns in the context of different strands from information theory, parameter estimation theory, array processing and wireless communication, the authors present a complete picture of the field. Topics covered include advanced multiple-antenna adaptive processing, ad hoc networking, MIMO, MAC protocols, space-time coding, cellular networks and cognitive radio, with the significance and effects of both internal and external interference a recurrent theme throughout. A broad, self-contained technical introduction to all the necessary mathematics, statistics, estimation theory and information theory is included, and topics are accompanied by a range of engaging end-of-chapter problems. With solutions available online, this is the perfect self-study resource for students of advanced wireless systems and wireless industry professionals.

System Design Issues in Dense Urban Millimeter Wave Cellular Networks

System Design Issues in Dense Urban Millimeter Wave Cellular Networks Book
Author : Mandar Narsinh Kulkarni
Publisher : Unknown
Release : 2018
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

Upcoming deployments of cellular networks will see an increasing use of millimeter wave (mmWave) frequencies, roughly between 20-100 GHz. The goal of this dissertation is to investigate some key design issues in dense urban mmWave cellular networks by developing mathematical models that are representative of these networks. In the first contribution, stochastic geometry (SG) is used to study the per user rate performance of multi-user MIMO (MU-MIMO) in downlink mmWave cellular network incorporating the impact of a spatially sparse blockage dependent multipath channel and hybrid precoding. Performance of MU-MIMO is then compared with single-user beamforming and spatial multiplexing in different network scenarios considering coverage, rate and power consumption tradeoffs to suggest when to use which MIMO scheme. The second contribution reconsiders a popular received signal power model used in system capacity analysis of MIMO wireless networks employing single user beamforming. A modification is suggested to the model by introducing a correction factor. An approximate analysis is done to justify incorporating such a factor and simulations are performed to validate it's importance. Although this contribution does not study a new system design issue for mmWave cellular, it highlights a shortcoming with using the popular received signal power model to study design issues in mmWave cellular networks. The third and fourth contributions investigate resource allocation in self-backhauled mmWave cellular networks. In order to enable affordable initial deployments of mmWave cellular, self-backhauling is envisioned as a cost-saving solution. The third contribution investigates how to divide resources between uplink and downlink for access and backhaul in self-backhauled networks with single hop wireless backhauling. The performance of dynamic time division duplexing (TDD) and integrated access-backhaul (IAB) is compared with static TDD and orthogonal access backhaul (OAB) strategies using a SG based model. The last contribution of this dissertation addresses the following key question for self-backhauled networks. What is the maximum extended coverage area that a single fiber site can support using multi-hop relaying, while still achieving a minimum target per user data rate? The problem of maximizing minimum per user rates is studied considering a series of deployments with a single fiber site and varying number of relays. Several design guidelines for multi-hop mmWave cellular networks are provided based on the analytical and empirical results.

Fluctuations of MIMO Wireless Channels

Fluctuations of MIMO Wireless Channels Book
Author : Ping-Heng Kuo
Publisher : Unknown
Release : 2008
ISBN : 9783836450713
Language : En, Es, Fr & De

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Book Description :

Multiple-input multiple-output (MIMO) communication technology has the potential to resolve the bottleneck in traffic capacity for future wireless networks. Applying MIMO techniques to mobile communication systems, the problem of channel fading between the transmitters and receivers, which results in received signal strength fluctuations, is inevitable. This book provides some analytical methodologies to investigate the variation of MIMO channels, based on some mathematical results of Brownian motion. In particular, accurate analytical approximations for the level crossing rate (LCR) and average fade duration (AFD) of the several MIMO channel metrics are derived. Also, the temporal behavior of MIMO channels is studied via Markov model constructions. In addition, the instantaneous signal to interference plus noise ratio (SINR) of eigenmode transmission with a feedback time delay is analyzed. Finally, the fluctuation of the channel in the frequency domain is examined due to its practical importance in orthogonal frequency division multiplexing (OFDM) systems.

Link Adaptation and Quality of Service Delivery in Mimo Wireless Network

Link Adaptation and Quality of Service Delivery in Mimo Wireless Network Book
Author : Etienne Alain Feukeu
Publisher : Unknown
Release : 2011
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

In a Wireless Local Area Network (WLAN), as the signal travels from the transmitter to the receiver, it experiences various forms of impairments that cause fading and path loss. To cater for this problem, monitoring the link between the transmitter and receiver becomes imperative. This study focuses on the design of a link adaptation algorithm that seeks to improve the quality of service delivery in IEEE 802.11n networks. From the results, it is shown that the Greedy Algorithm (GA) performed far better than that of Auto-Rate-Fallback (ARF) and it is also shown that the Optimal Algorithm (OA) approach outperformed GA and ARF in terms of throughput and efficiency. Simulations results of both proposed algorithms proved to be more efficient than the existing ARF algorithm. Thus, it is shown that the proposed algorithms have the potential of enhancing the quality of service in IEEE 802.11n network.

Performance of Wireless Networks Using MIMO Transceivers

Performance of Wireless Networks Using MIMO Transceivers Book
Author : Chris Xin Gao
Publisher : Unknown
Release : 2006
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

The research and development of wireless cellular networks has experienced rapid advances in the past decades. Multiple input/multiple output (MIMO) transceivers have emerged as a promising direction potentially capable of delivering the data rates demanded by today's multimedia applications over wireless radio networks. In this thesis, we study some of the theoretical and implementation issues of MIMO transceivers.Although spectrally efficient space-time codes have been studied intensively, most of these studies focus on fulfilling full spatial diversity gain while few on maximizing the coding gain of the codes. Based on the previous work on maximal product distance constellations (MPDC), we propose a transmission scheme that achieves a high coding gain while maintaining the full spatial diversity gain. Compared with the Alamouti space-time scheme, the MDPC based transmission scheme achieves 5, 10, and 15 dB performance gain, at the symbol-error rate of 10-4, for transmit antennas of 2, 3, and 4 elements, respectively. Although the SNR gains can not be interpreted directly numerically as they are because of the unfair restrictions of multi-level AM constellations on the Alamouti scheme, it indeed stresses the fact that, for MIMO radio channels, riot only the diversity advantage but also the coding advantage must be equally emphasized in designing transmission schemes.For synchronized forward links of cellular networks, all signals share the same temporal and spatial signatures of the channel impulse response. The third part of this thesis extends the conventional subspace method to enhance the performance of channel estimation by exploiting this feature. We investigate two transmission schemes: fixed beam transmission and adaptive beam transmission. We conclude that the extended subspace approach does have performance impact on fixed beam schemes while it is not directly applicable to adaptive beam transmissions.The knowledge of the channel information can be used to improve the performance of MIMO links. However, the inaccuracy of the channel estimation and prediction methods may render such performance potential unrealizable. In the second part of this thesis, through a set of simulations for two-element transmit antennas, we derive the velocity thresholds at which transmit beamforming with inaccurate channel information has comparable performance with the Alamouti scheme. These thresholds can be used as rough guidelines in deciding when to beamform.

Relaying and Multiuser MIMO Communications in Wireless Networks

Relaying and Multiuser MIMO Communications in Wireless Networks Book
Author : Hall Yip Louie
Publisher : Unknown
Release : 2010
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

Download Relaying and Multiuser MIMO Communications in Wireless Networks book written by Hall Yip Louie, available in PDF, EPUB, and Kindle, or read full book online anywhere and anytime. Compatible with any devices.

Hardware Co processor to Enable MIMO in Next Generation Wireless Networks

Hardware Co processor to Enable MIMO in Next Generation Wireless Networks Book
Author : Nathaniel Horner
Publisher : Unknown
Release : 2010
ISBN : 0987650XXX
Language : En, Es, Fr & De

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Book Description :

"One prevailing technology in wireless communication is Multiple Input, Multiple Output (MIMO) communication. MIMO communication simultaneously transmits several data streams, each from their own antenna within the same frequency channel. This technique can increase data bandwidth by up to a factor of the number of transmitting antennas, but comes with the cost of a much higher computational complexity for the wireless receiver. MIMO communication exploits differing channel effects caused by physical distances between antennas to differentiate between transmitting antennas, an intrinsically two dimensional operation. Current Digital Signal Processors (DSPs), on the other hand, are designed to perform computations on one dimensional vectors of incoming data. To compensate for the lack of native support of these higher dimensional operations, current base stations are forced to add multiple new processing elements while many mobile devices cannot support MIMO communication. In order to allow wireless clients and stations to have native support of the two dimensional operations required by MIMO communication, a hardware co-processor was designed to allow the DSP to offload these operations onto another processor to reduce computation time."--Abstract.