Download or read book Design and Performance Analysis of a Low Complexity MIMO OFDM System with Walsh Block Coding written by Amr Hussein El Mougy and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: There are many technologies being considered for the next generation of wireless communications. Of these technologies, multi-input multi-output (MIMO), orthogonal frequency division multiplexing (OFDM) and Walsh spreading are drawing the most attention. Although a lot of research has been done in this area, it has not been decided yet as to which technology or combination of the technologies will be used in future wireless generations. The new generation will have to support high data rates and provide excellent performance in order to accommodate several multimedia services. In this thesis, a MIMO-OFDM system that employs Walsh sequences as block coding is designed. Simulation studies show that the proposed system exhibits high performance and comparisons show that it has low complexity compared to some of the previous systems. Two configurations are considered for the proposed system. The first configuration combines Vertical-Bell Labs Layered Space-Time (VBLAST), OFDM and Walsh block coding, for which a simplified implementation scheme for the proposed coding is presented. The system is investigated through extensive computer simulations using different system parameters and channel conditions. The proposed system is compared to some of the existing systems in terms of performance as well as computational complexity. The second configuration integrates space-time block coding (STBC), OFDM and Walsh block coding. In contrast to VBLAST, which aims to increase system capacity and data rates, STBC improves the system's performance through multipath diversity. The performance of the system is studied through computer simulations and the computational complexity of the system is also compared to some typical STBC systems from previous research. The simulations and comparisons of both configurations of the proposed system show its superiority in terms of performance and computational complexity to previous systems. Finally, to emulate real-life scenarios, the performance of the proposed system is also investigated using some common channel estimation techniques. It is shown that by utilizing a preamble of training symbols, the proposed system provides a satisfactory performance for both the configurations.
Download or read book PERFORMANCE ANALYSIS OF MIMO OFDM SYSTEM USING CODING AND EQUALIZATION written by G.KRISHNA REDDY and published by Archers & Elevators Publishing House. This book was released on with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book OFDM and MC CDMA written by Lajos Hanzo and published by John Wiley & Sons. This book was released on 2007-01-11 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wireless communications has witnessed a tremendous growth during the past decade and further spectacular enabling technology advances are expected in an effort to render ubiquitous wireless connectivity a reality. Currently, a technical in-depth book on this subject is unavailable, which has a similar detailed exposure of OFDM, MIMO-OFDM and MC-CDMA. A further attraction of the joint treatment of these topics is that it allows the reader to view their design trade-offs in a comparative context. Divided into three main parts: Part I provides a detailed exposure of OFDM designed for employment in various applications Part II is another design alternative applicable in the context of OFDM systems where the channel quality fluctuations observed are averaged out with the aid of frequency-domain spreading codes, which leads to the concept of MC-CDMA Part III discusses how to employ multiple antennas at the base station for the sake of supporting multiple users in the uplink By providing an all-encompassing self-contained treatment this volume will appeal to a wide readership, as it is both an easy-reading textbook and a high-level research monograph.
Download or read book Space time frequency Block Codes for MIMO OFDM in Next Generation Wireless Systems written by Min Zhang and published by . This book was released on 2010 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis the use of space-frequency block codes (SFBC) and space-time-frequency block codes (STFBC) in wireless systems are investigated. A variety of SFBC and STFBC schemes are proposed for particular propagation scenarios and system settings where each has its own advantages and disadvantages. The objective is to pro-pose coding strategies with improved flexibility, feasibility and spectral efficiency,and reduce the decoding complexity in an MIMO-OFDM system.
Download or read book Master s Theses Directories written by and published by . This book was released on 2007 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Education, arts and social sciences, natural and technical sciences in the United States and Canada".
Download or read book Low Complexity Space Time Coding for MIMO Systems written by Amr Ismail and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The last few years witnessed a dramatic increase in the demand on high-rate reliable wireless communications. In order to meet these new requirements, resorting to Multiple-Input Multiple-Output (MIMO) techniques was inevitable as they may offer high-rate reliable wireless communications without any additional bandwidth. In the case where the transmitter does not have any prior knowledge about the channel state information, space-time coding techniques have proved to efficiently exploit the MIMO channel degrees of freedom while taking advantage of the maximum diversity gain. On the other hand, the ML decoding complexity of Space-Time Codes (STCs) generally increases exponentially with the rate which imposes an important challenge to their incorporation in recent communications standards. Recognizing the importance of the low-complexity criterion in the STC design for practical considerations, this thesis focuses on the design of new low-complexity Space-Time Block Codes (STBCs) where the transmitted code matrix can be expressed as a weighted linear combination of information symbols and we propose new codes that are decoded with a lower complexity than that of their rivals in the literature while providing better or slightly lower performance.
Download or read book Layered Space time Structure for MIMO OFDM Systems written by Jianxuan Du and published by . This book was released on 2005 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Low Complexity Space frequency Waveform Design for Mimo ofdm Systems written by Yoav Eisenberg and published by . This book was released on 2010 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Performance Evaluation of Space Time Frequency Codes in Mimo Ofdm written by Gunjan Manik and published by LAP Lambert Academic Publishing. This book was released on 2012-05 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Channel Estimation and Performance Analysis of MIMO OFDM Communications Using Space time and Space frequency Coding Schemes written by Fabien Delestre and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Low Complexity Adaptive Semi blind Space time Block Code MIMO CDMA Receiver Design written by Yu-Chia Chen and published by . This book was released on 2015 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Performance Analysis of MIMO OFDM Systems written by Raghu Mysore Rao and published by . This book was released on 2004 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Performance Analysis of Space time Trellis Coded MIMO OFDM Systems written by Samet Yildiz and published by . This book was released on 2015 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Space-time codes are a standout amongst the most prominent procedure utilized as a part of the multiple-input multiple-output (MIMO) systems in the advanced communication systems. While ordinary transmission between one transmit and one receive antenna is utilized, one can see neither diversity gain nor coding gain, which eventually implies that a critical change in the transmission cannot be observed. Space-time codes can be effectively connected through multiple transmit antennas and optional number of receive antennas. There are several approaches to provide diversity gain. The researches which are developed to achieve diversity gain by late 1990's are called as space-time block codes (STBC). Despite the fact that the STBC is anything but easy to execute, they do not provide any coding gain. Subsequently, so as to accomplish the coding gain other than the diversity gain, the space-time trellis codes (STTC) are connected all through this theory. STTC, which gives coding gain in regards to the number of the states, is then joined with the orthogonal frequency division multiplexing (OFDM) systems, which is a prominent transmission method to send orthogonal signals with no interference between the subcarriers. It is ultimately called as STTC-OFDM systems.
Download or read book Wireless Communications over MIMO Channels written by Volker Kuhn and published by John Wiley & Sons. This book was released on 2006-07-11 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wireless Communications over MIMO Channels: Applications to CDMA and Multiple Antenna Systems covers both, state-of-the-art channel coding concepts and CDMA and multiple antenna systems, rarely found in other books on the subject. Furthermore, an information theoretical analysis of CDMA and SDMA systems illuminate ultimate limits and demonstrates the high potential of these concepts. Besides spatial multiplexing, the use of multiple transmit antennas in order to increase the link reliability by diversity concepts (space-time coding) is described. Another focus is the application of error control coding in mobile radio communications Accompanying appendices include: basic derivations, tables of frequently used channel models, chain rules for entropy and information, data processing theorem, basics of linear algebra, Householder reflection and Givens rotation, and the LLL algorithm for lattice reduction.
Download or read book OFDM Baseband Receiver Design for Wireless Communications written by Tzi-Dar Chiueh and published by John Wiley & Sons. This book was released on 2008-04-15 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Orthogonal frequency-division multiplexing (OFDM) access schemes are becoming more prevalent among cellular and wireless broadband systems, accelerating the need for smaller, more energy efficient receiver solutions. Up to now the majority of OFDM texts have dealt with signal processing aspects. To address the current gap in OFDM integrated circuit (IC) instruction, Chiueh and Tsai have produced this timely text on baseband design. OFDM Baseband Receiver Design for Wireless Communications covers the gamut of OFDM technology, from theories and algorithms to architectures and circuits. Chiueh and Tsai give a concise yet comprehensive look at digital communications fundamentals before explaining modulation and signal processing algorithms in OFDM receivers. Moreover, the authors give detailed treatment of hardware issues -- from design methodology to physical IC implementation. Closes the gap between OFDM theory and implementation Enables the reader to transfer communication receiver concepts into hardware design wireless receivers with acceptable implementation loss achieve low-power designs Contains numerous figures to illustrate techniques Features concrete design examples of MC-CDMA systems and cognitive radio applications Presents theoretical discussions that focus on concepts rather than mathematical derivation Provides a much-needed single source of material from numerous papers Based on course materials for a class in digital communication IC design, this book is ideal for advanced undergraduate or post-graduate students from either VLSI design or signal processing backgrounds. New and experienced engineers in industry working on algorithms or hardware for wireless communications devices will also find this book to be a key reference.
Download or read book Baseband Receiver Design for Wireless MIMO OFDM Communications written by Tzi-Dar Chiueh and published by John Wiley & Sons. This book was released on 2012-04-24 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Second Edition of OFDM Baseband Receiver Design for Wirless Communications, this book expands on the earlier edition with enhanced coverage of MIMO techniques, additional baseband algorithms, and more IC design examples. The authors cover the full range of OFDM technology, from theories and algorithms to architectures and circuits. The book gives a concise yet comprehensive look at digital communication fundamentals before explaining signal processing algorithms in receivers. The authors give detailed treatment of hardware issues - from architecture to IC implementation. Links OFDM and MIMO theory with hardware implementation Enables the reader to transfer communication received concepts into hardware; design wireless receivers with acceptable implemntation loss; achieve low-power designs Covers the latest standards, such as DVB-T2, WiMax, LTE and LTE-A Includes more baseband algorithms, like soft-decoding algorithms such as BCJR and SOVA Expanded treatment of channel models, detection algorithms and MIMO techniques Features concrete design examples of WiMAX systems and cognitive radio apllications Companion website with lecture slides for instructors Based on materials developed for a course in digital communication IC design, this book is ideal for graduate students and researchers in VLSI design, wireless communications, and communications signal processing. Practicing engineers working on algorithms or hardware for wireless communications devices will also find this to be a key reference.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt:
