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| Author | : Bhasker Gupta |
| Publisher | : |
| Total Pages | : 180 |
| Release | : 2017-01-24 |
| Genre | : |
| ISBN | : 9783330023062 |
| Author | : Alex Gershman |
| Publisher | : John Wiley & Sons |
| Total Pages | : 388 |
| Release | : 2005-08-05 |
| Genre | : Technology & Engineering |
| ISBN | : 0470010037 |
Driven by the desire to boost the quality of service of wireless systems closer to that afforded by wireline systems, space-time processing for multiple-input multiple-output (MIMO) wireless communications research has drawn remarkable interest in recent years. Exciting theoretical advances have been complemented by rapid transition of research results to industry products and services, thus creating a vibrant new area. Space-time processing is a broad area, owing in part to the underlying convergence of information theory, communications and signal processing research that brought it to fruition. This book presents a balanced and timely introduction to space-time processing for MIMO communications, including highlights of emerging trends, such as spatial multiplexing and joint transceiver optimization. Includes detailed coverage of wireless channel sounding, modelling, characterization and model validation. Provides state-of-the-art research results on space-time coding, including comprehensive tutorial coverage of orthogonal space-time block codes. Discusses important recent developments in spatial multiplexing, transmit beam-forming, pre-coding and joint transceiver design for the multi-user MIMO downlink using full or partial CSI. Illustrates all theory with numerous examples gleaned from cutting-edge research from around the globe. This valuable resource will appeal to engineers, developers and consultants involved in the design and implementation of space-time processing for MIMO communications. Its accessible format, amply illustrated with real world case studies, contains relevant, detailed advice for postgraduate students and researchers specializing in this field.
| Author | : Jianjun Ran |
| Publisher | : Cuvillier Verlag |
| Total Pages | : 161 |
| Release | : 2008 |
| Genre | : |
| ISBN | : 3867276498 |
| Author | : Mohinder Jankiraman |
| Publisher | : Artech House |
| Total Pages | : 354 |
| Release | : 2004 |
| Genre | : Computers |
| ISBN | : 9781580538664 |
Annotation "This resource takes professionals step by step from the basics of MIMO through various coding techniques, to critical topics such as multiplexing and packet transmission. Practical examples are emphasized and mathematics is kept to a minimum, so readers can quickly and thoroughly understand the essentials of MIMO. The book takes a systems view of MIMO technology that helps professionals analyze the benefits and drawbacks of any MIMO system."--BOOK JACKET.Title Summary field provided by Blackwell North America, Inc. All Rights Reserved.
| Author | : Fabien Delestre |
| Publisher | : |
| Total Pages | : |
| Release | : 2011 |
| Genre | : |
| ISBN | : |
This thesis is concerned with channel estimation and data detection of MIMO-OFDM communication systems using Space-Time Block Coding (STBC) and Space-Frequency Block Coding (SFBC) under frequency selective channels. A new iterative joint channel estimation and signal detection technique for both STBC-OFDM and SFBC-OFDM systems is proposed. The proposed algorithm is based on a processive sequence of events for space time and space frequency coding schemes where pilot subcarriers are used for channel estimation in the first time instant, and then in the second time instant, the estimated channel is used to decode the data symbols in the adjacent data subcarriers. Once data symbols are recovered, the system recursively performs a new channel estimation using the decoded data symbols as pilots. The iterative process is repeated until all MIMO-OFDM symbols are recovered. In addition, the proposed channel estimation technique is based on the maximum likelihood (ML) approach which offers linearity and simplicity of implementation. Due to the orthogonality of STBC and SFBC, high computation efficiency is achieved since the method does not require any matrix inversion for estimation and detection at the receiver. Another major novel contribution of the thesis is the proposal of a new group decoding method that reduces the processing time significantly via the use of sub-carrier grouping for transmitted data recovery. The OFDM symbols are divided into groups to which a set of pilot subcarriers are assigned and used to initiate the channel estimation process. Designated data symbols contained within each group of the OFDM symbols are decoded simultaneously in order to improve the decoding duration. Finally, a new mixed STBC and SFBC channel estimation and data detection technique with a joint iterative scheme and a group decoding method is proposed. In this technique, STBC and SFBC are used for pilot and data subcarriers alternatively, forming the different combinations of STBC/SFBC and SFBC/STBC. All channel estimation and data detection methods for different MIMO-OFDM systems proposed in the thesis have been simulated extensively in many different scenarios and their performances have been verified fully.
| Author | : Jianxuan Du |
| Publisher | : |
| Total Pages | : 94 |
| Release | : 2005 |
| Genre | : MIMO systems |
| ISBN | : |
The low complexity of layered processing makes the layered structure a promising candidate for MIMO systems with a large number of transmit antennas and higher order modulation. For broadband systems, orthogonal frequency division multiplexing (OFDM) appears promising for its immunity against delay spread. In addition, OFDM is especially suitable for frequency selective MIMO systems since the introduction of orthogonal subcarriers makes system design and implementation as simple as those for flat fading channels. Therefore, the combination of layered structure with OFDM is a promising technique for high-speed wireless data transmission. The proposed research is focused on the layered structure for MIMO-OFDM systems, where several techniques are proposed for performance enhancement, namely, channel estimation based on subspace tracking, parallel detection of group-wise space-time codes by predictive soft interference cancellation, quasi-block diagonal low-density parity-check codes (LDPC) coding and statistical data rate allocation for layered systems. For MIMO-OFDM systems, rank reduction by some linear transform matrix is necessary for channel estimation. In the proposed research, we propose a channel estimation algorithm for MIMO-OFDM systems, which uses the optimum low-rank channel approximation obtained by tracking the frequency autocorrelation matrix of the channel response. Then parallel detection algorithm is proposed for a modified layered system with group-wise space-time coding, where the structure of particular component space-time code trellises is exploited using partial information from the Viterbi decoder of the simultaneously decoded interfering component codes. Next we incorporate the layered structure with LDPC to develop a quasi-block diagonal LDPC space-time structure. The lower triangular structure of the parity check matrix introduces correlation between layers. Each layer, as a part of the whole codeword, can be decoded while taking information from other undetected layers to improve the decoding performance. In the end, a modified layered structure is proposed where the layer detection order is fixed and the data rate for each layer is allocated based on the detection order and channel statistics. With Gaussian approximation of layer capacities, we derive the optimum data rate allocation.
| Author | : Bannour Ahmed |
| Publisher | : Springer |
| Total Pages | : 99 |
| Release | : 2015-05-27 |
| Genre | : Technology & Engineering |
| ISBN | : 3319191535 |
This book introduces the reader to the MIMO-OFDM system, in Rayleigh frequency selective-channels. Orthogonal frequency division multiplexing (OFDM) has been adopted in the wireless local-area network standards IEEE 802.11a due to its high spectral efficiency and ability to deal with frequency selective fading. The combination of OFDM with spectral efficient multiple antenna techniques makes the OFDM a good candidate to overcome the frequency selective problems.
| Author | : Zhefeng Li |
| Publisher | : |
| Total Pages | : |
| Release | : 2010 |
| Genre | : MIMO systems |
| ISBN | : 9781124240985 |
Space-time-frequency coded Multiple-Input and Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) systems have recently attracted much attention for broadband wireless communications including recent IEEE standards 802.11n and 802.16e. Space-time/Frequency Coding (SFC) can achieve the spatial and multipath diversities for a MIMO-OFDM system by coding across multiple antennas and subcarriers. In this research, we focus on a family of space-time-frequency codes proposed by Zhang et al to achieve both full spatial and multipath diversities by using Orthogonal Space-Time Block Codes (OSTBC). In particular, we develop a precoding algorithm for Peak-to-Average Power Ratio (PAPR) reduction and a clipping noise model based Maximum Likelihood (ML) decoding algorithm for Space-Time-Frequency Block Codes (STFBC) coded MIMO-OFDM systems. An important issue for OFDM systems is their high PAPR and it is important to reduce the PAPR in a practical (power efficient) system. The first goal of this research is to modify the repeating process and adjust phases of coded symbols so that the PAPR of the OFDM system is reduced. In particular, we propose to use Chu sequences for phase adjustment and show that the discrete PAPR can be reduced by & Gamma; times where & Gamma; is the times of the repeating across subcarriers. Another efficient way to reduce the PAPR in OFDM systems is clipping. After the clipping in an MIMO-OFDM system, the overall additive noise, including the clipping distortion, may not be white. The second goal of this research is to develop fast ML decoding algorithms for Orthogonal Space-Time-Frequency Block Codes (OSTFBC) and Quasi Orthogonal Space-Time-Frequency Block Codes (QOSTFBC) in clipped MIMO-OFDM systems. By using a clipping noise model with Gaussian approximation, our newly proposed fast ML decoding algorithms improve the system performance without increasing the decoding complexity. Simulation results are presented to illustrate the improvement. In order to apply the clipping noise model based ML decoding, the clipping ratio needs to be known at the receiver. We also consider the case when the clipping ratio is not known at the receiver. So a decision-aided clipping ratio estimation for MIMO-OFDM systems is proposed in our research, too. Except for MIMO-OFDM systems, in this work, cooperative OFDM system is investigated too. OFDM transmission has been proposed for cooperative communications to combat the time delays from the relay nodes, where the paths from relay nodes to destination node are treated as multipaths and space-time (or frequency) coding is used to achieve the spatial (or multipath) diversity. With this approach, when the Cyclic Prefix (CP) length is less than the time delay length, inter-block interference occurs. In this research, we consider Alamouti coded OFDM systems in cooperative communications where the CP length may be less than the time delay length. By taking the advantage of the Alamouti code structure, we propose a time domain interference cancellation algorithm.
| Author | : Gunjan Manik |
| Publisher | : LAP Lambert Academic Publishing |
| Total Pages | : 76 |
| Release | : 2012-05 |
| Genre | : |
| ISBN | : 9783659108389 |
High spectral efficiency and high transmission data rate are the challenging requirements of wireless broadband communications. The MIMO technology has rapidly gained in popularity due to its powerful performance-enhancing capabilities. Spatial diversity can be obtained by using multiple antennas and space-time codes. For future wireless broadband systems, OFDM is discussed as access scheme. OFDM provides an essentially flat fading channel for each subcarrier by insertion of a cyclic guard interval at each antenna. Therefore, space-time block codes are well suited to be applied in OFDM. We investigate SFBC for OFDM systems with multiple transmit antennas, where coding is applied in the frequency domain rather than in the time domain. In this thesis, performance of two coding techniques STBC and SFBC is analyzed in OFDM. In order to appreciate the performances offered by coding through space and frequency, different simulation scenarios have been proposed where variation of the modulation order , channel fading, antenna selection technique, receiver diversity and effect of power conditions have been considered.
| Author | : Yong Soo Cho |
| Publisher | : John Wiley & Sons |
| Total Pages | : 458 |
| Release | : 2010-08-20 |
| Genre | : Technology & Engineering |
| ISBN | : 0470825626 |
MIMO-OFDM is a key technology for next-generation cellular communications (3GPP-LTE, Mobile WiMAX, IMT-Advanced) as well as wireless LAN (IEEE 802.11a, IEEE 802.11n), wireless PAN (MB-OFDM), and broadcasting (DAB, DVB, DMB). In MIMO-OFDM Wireless Communications with MATLAB®, the authors provide a comprehensive introduction to the theory and practice of wireless channel modeling, OFDM, and MIMO, using MATLAB® programs to simulate the various techniques on MIMO-OFDM systems. One of the only books in the area dedicated to explaining simulation aspects Covers implementation to help cement the key concepts Uses materials that have been classroom-tested in numerous universities Provides the analytic solutions and practical examples with downloadable MATLAB® codes Simulation examples based on actual industry and research projects Presentation slides with key equations and figures for instructor use MIMO-OFDM Wireless Communications with MATLAB® is a key text for graduate students in wireless communications. Professionals and technicians in wireless communication fields, graduate students in signal processing, as well as senior undergraduates majoring in wireless communications will find this book a practical introduction to the MIMO-OFDM techniques. Instructor materials and MATLAB® code examples available for download at www.wiley.com/go/chomimo
