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Author : Zhen Lu
Publisher :
ISBN 13 :
Total Pages : 264 pages
Book Rating : 4.:/5 (71 download)
Download or read book An Improved Channel Estimation Approach for MIMO-OFDM Systems written by Zhen Lu and published by . This book was released on 2010 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Jianjun Ran
Publisher : Cuvillier Verlag
ISBN 13 : 3867276498
Total Pages : 161 pages
Book Rating : 4.8/5 (672 download)
Download or read book Signal Processing, Channel Estimation and Link Adaptation in MIMO-OFDM Systems written by Jianjun Ran and published by Cuvillier Verlag. This book was released on 2008 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Dr.Maddala Vijayalakshmi
Publisher : Archers & Elevators Publishing House
ISBN 13 : 8119385969
Total Pages : 58 pages
Book Rating : 4.1/5 (193 download)
Download or read book EFFECTIVE SPARSE CHANNEL ESTIMATION TECHNIQUE FOR MIMO-OFDM SYSTEM written by Dr.Maddala Vijayalakshmi and published by Archers & Elevators Publishing House. This book was released on with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Fabien Delestre
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (855 download)
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.
Author : Feng Wan
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (462 download)
Download or read book Signal-perturbation-free Semi-blind Channel Estimation for MIMO-OFDM Systems written by Feng Wan and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) has been considered as a strong candidate for the beyond 3G (B3G) wireless communication systems, due to its high data-rate wireless transmission performance. It is well known that the advantages promised by MIMO-OFDM systems rely on the precise knowledge of the channel state information (CSI). In real wireless environments, however, the channel condition is unknown. Therefore, channel estimation is of crucial importance in MIMO-OFDM systems. Semi-blind channel estimation as a combination of the training-based or pilot-assisted method and the pure blind approach is considered to be a feasible solution for practical wireless systems due to its better estimation accuracy as well as spectral efficiency. In this thesis, we address the semi-blind channel estimation issue of MIMO-OFDM systems with an objective to develop very efficient channel estimation approaches. In the first part of the dissertation, several nulling-based semi-blind approaches are presented for the estimation of time-domain MIMO-OFDM channels. By incorporating a blind constraint that is derived from MIMO linear prediction (LP) into a training-based least-square method, a semi-blind solution for the time-domain channel estimation is first obtained. It is revealed through a perturbation analysis that the semi-blind solution is not subject to signal perturbation and therefore is superior to pure blind estimation methods. The LP-based semi-blind method is then extended for the channel estimation of MIMO-OFDM systems with pulse-shaping. By exploiting the pulse-shaping filter in the transmitter and the matched filter in the receiver, a very efficient semi-blind approach is developed for the estimation of sampling duration based multipath channels. A frequency-domain correlation matrix estimation algorithm is also presented to facilitate the computation of time-domain second-order statistics required in the LP-based method. The nulling-based semi-blind estimation issue of sparse MIMO-OFDM channels is also addressed. By disclosing and using a relationship between the positions of the most significant taps (MST) of the sparse channel and the lags of nonzero correlation matrices of the received signal, a novel estimation approach consisting of the MST detection and the sparse channel estimation, both in a semi-blind fashion, is developed. An intensive simulation study of all the proposed nulling-based methods with comparison to some existing techniques is conducted, showing a significant superiority of the new methodologies. The second part of the dissertation is dedicated to the development of two signal-perturbation-free (SPF) semi-blind channel estimation algorithms based on a novel transmit scheme that bears partial information of the second-order statistics of the transmitted signal to receiver. It is proved that the new transmit scheme can completely cancel the signal perturbation error in the noise-free case, thereby improving largely the estimation accuracy of correlation matrix for channel estimation in noisy conditions. It is also shown that the overhead caused by the transmission of the 8PF data is negligible as compared to that of regular pilot signals. By using the proposed transmit scheme, a whitening rotation (WR)-based algorithm is first developed for frequency-domain MIMO-OFDM channel estimation. It is shown through both theoretical analysis and simulation study that the new WR-based algorithm significantly outperforms the conventional WR-based method and the nulling-based semi-blind method. By using MIMO linear prediction, the new WR-based algorithm utilizing the 8PF transmit scheme is then extended for time-domain MIMO-OFDM channel estimation. Computer simulations show that the proposed signal-perturbation-free LP-based semi-blind solution performs much better than the LP semi-blind method without using the proposed transmit scheme, the LS method as well as the nulling-based semi-blind method in terms of the MSE of the channel estimate.
Author : Hui Jin
Publisher :
ISBN 13 :
Total Pages : 294 pages
Book Rating : 4.:/5 (319 download)
Download or read book Improved Synchronization and Channel Estimation Methods for Communication System written by Hui Jin and published by . This book was released on 2004 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Aymen Omri
Publisher : LAP Lambert Academic Publishing
ISBN 13 : 9783659136306
Total Pages : 164 pages
Book Rating : 4.1/5 (363 download)
Download or read book Channel Estimation for Lte Mimo-Ofdm Systems written by Aymen Omri and published by LAP Lambert Academic Publishing. This book was released on 2012-05 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nowadays, the requirements in terms of communication are increasing exponentially and getting more diverse. The transmission data rates must be high while maintaining very good quality of service (QoS) despite the very hostile propagation channels. Generally, transmissions that are carried out on mobile radio channels are selective both in time and frequency. To overcome the channel selectivity and allows high transmission data rates, the Long Term Evolution (LTE) standard makes use of the Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing (MIMO-OFDM) technique. By implementing this technique in the context of mobile transmission, new approaches for time and frequency synchronization, equalization and channel estimation are needed. This book focuses on the study, modeling and development of efficient channel estimation techniques for broadband mobile radio channels and specifically for LTE systems. This book is interesting for both undergraduate and postgraduate students in the field of wireless communication systems. The professional engineers will find also this book useful in improving and designing new wireless communication systems.
Author : Wichai Pongwilai
Publisher :
ISBN 13 : 9789744660084
Total Pages : 306 pages
Book Rating : 4.6/5 (6 download)
Download or read book Improved Channel Estimation Techniques for OFDM Systems in Frequency Selective Fading Channels written by Wichai Pongwilai and published by . This book was released on 2004 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Li Li
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (868 download)
Download or read book Advanced Channel Estimation and Detection Techniques for MIMO and OFDM Systems written by Li Li and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : İlhan Baştürk
Publisher :
ISBN 13 :
Total Pages : 156 pages
Book Rating : 4.:/5 (421 download)
Download or read book Iterative Channel Estimation Techniques For Multiple İnput Multiple Output Orthogonal Frequency Division Multiplexing Systems written by İlhan Baştürk and published by . This book was released on 2007 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Orthogonal frequency division multiplexing (OFDM) is well-known for its efficient high speed transmission and robustness to frequency-selective fading channels. On the other hand, multiple-input multiple-output (MIMO) antenna systems have the ability to increase capacity and reliability of a wireless communication system compared to single-input single-output (SISO) systems. Hence, the integration of the two technologies has the potential to meet the ever growing demands of future communication systems. In these systems, channel estimation is very crucial to demodulate the data coherently. For a good channel estimation, spectral efficiency and lower computational complexity are two important points to be considered. In this thesis, we explore different channel estimation techniques in order to improve estimation performance by increasing the bandwidth efficiency and reducing the computational complexity for both SISO-OFDM and MIMO-OFDM systems. We first investigate pilot and Expectation-Maximization (EM)-based channel estimation techniques and compare their performances. Next, we explore different pilot arrangements by reducing the number of pilot symbols in one OFDM frame to improve bandwidth efficiency. We obtain the bit error rate and the channel estimation performance for these pilot arrangements. Then, in order to decrase the computational complexity, we propose an iterative channel estimation technique, which establishes a link between the decision block and channel estimation block using virtual subcarriers. We compare this proposed technique with EM-based channel estimation in terms of performance and complexity. These channel estimation techniques are also applied to STBC-OFDM and V-BLAST structured MIMO-OFDM systems. Finally, we investigate a joint EM-based channel estimation and signal detection technique for V-BLAST OFDM system.
Author : Wen Zhou
Publisher : Open Dissertation Press
ISBN 13 : 9781360996394
Total Pages : 208 pages
Book Rating : 4.9/5 (963 download)
Download or read book STUDY OF CHANNEL ESTIMATION FO written by Wen Zhou and published by Open Dissertation Press. This book was released on 2017-01-26 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "A Study of Channel Estimation for OFDM Systems and System Capacity for MIMO-OFDM Systems" by Wen, Zhou, 周雯, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. DOI: 10.5353/th_b4555585 Subjects: Orthogonal frequency division multiplexing - Mathematical models MIMO systems - Mathematical models
Download or read book Channel Estimation Techniques for OFDM Systems in Dispersive Time-varying Channels written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Coherent modulation is more effective than differential modulation for orthogonal frequency division multiplexing (OFDM) systems requiring high data rate and spectral efficiency. Channel estimation is therefore an integral part of the receiver design. In this thesis, two iterative maximum likelihood based channel estimation algorithms are proposed for an OFDM system in dispersive time-varying channels. A multipath channel model is proposed for OFDM uplink transmission in macrocellular systems. The multipath fading channel is modeled such that the channel state can be determined by estimating the unknown channel parameters. A second-order Taylor series expansion is adopted to simplify the channel estimation problem. Based on the system model, an iterative maximum likelihood based algorithm is first proposed to estimate the discrete-time channel parameters. The mean square error performance of the proposed algorithm is analyzed using a small perturbation technique. Based on a convergence rate analysis, an improved iterative maximum likelihood based channel estimation algorithm is presented using a successive overrelaxation method. Numerical experiments are performed to confirm the theoretical analyses and show the improvement in convergence rate of the improved algorithm.
Author : Chao-Cheng Tu
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (697 download)
Download or read book Subspace-based Blind Channel Estimation and Tracking for MIMO-OFDM Systems written by Chao-Cheng Tu and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Andrew Paul Millar
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (141 download)
Download or read book Channel Estimation and Non-linear Transceiver Designs for MIMO OFDM Relay Systems written by Andrew Paul Millar and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiple-input multiple output (MIMO) systems deploy multiple antennas at either end of a communication link and can provide significant benefits compared to traditional single antenna systems, such as increased data rates through spatial multiplexing gain, and/or improved link reliability through diversity techniques. Recently, the natural extension of utilising multiple antennas in relay networks, known as MIMO relaying, has attracted significant research attention due to the fact that the benefits of MIMO can be coupled with extended network coverage through the use of relaying devices. This thesis concentrates on the design and analysis of different aspects of MIMO relay systems communicating over frequency selective channels with the use of orthogonal frequency division multiplexing (OFDM). The first focus of this thesis is on the development of training based channel estimation algorithms for two-hop MIMO OFDM relaying. In the first phase of channel estimation the relay-destination channel is estimated using conventional point-to-point MIMO estimation techniques. In the second phase, the source sends known training symbols to the relay, which precodes the received symbols and forwards them to the destination. In order to estimate the source-relay channel at the destination, an iterative algorithm is derived, which involves sequentially solving a number of convex optimisation problems and has guaranteed convergence. Since the proposed iterative algorithm may be too computationally complex for practical systems, a simplified approach is also derived where the channel estimation processors can be calculated in closed form. Under the assumption of perfect channel state information (CSI), we then develop non-linear transceiver designs for MIMO OFDM relay systems, focusing specifically on decision feedback equalisation (DFE) and Tomlinson Harashima precoding (THP). The optimal source and relay precoding matrices are derived that minimise the arithmetic mean square error (MSE) subject to source and relay transmission power constraints, when either a zero forcing (ZF) or minimum mean square error (MMSE) equaliser is used at the destination. Simulation results demonstrate that the proposed non-linear solutions outperform linear transceivers in terms of bit error rate (BER) and MSE. For the case of imperfect CSI at all nodes, robust DFE and THP transceivers are then considered that aim to minimise the expected artithmetic MSE subject to the source and relay transmission power constraints. The channel estimation errors are modelled as being drawn from matrix variate Gaussian distributions with known mean and covariance. The source and relay precoder structures are derived for the case that the optimal MMSE equaliser is used at the destination. The derived precoder structures are shown to be optimal for the special case that the channel estimation errors are uncorrelated. Simulation results demonstrate the robustness of the proposed algorithms to channel estimation errors.
Download or read book Soft Computing Approach to Channel Estimation for MIMO OFDM Systems written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents an TSK fuzzy approach to channel estimation for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. The information of dispersive fading channel is described by using a TSK fuzzy model, which is updated by using the decision feedback symbol or the scattered pilot symbol. Space-time block coding (STBC) is used to get the diversity gain. Computer simulations demonstrate the bit error rate (BER) performance and compare to the minimum mean-square-error (MMSE) method. The advantage of this method lies in the reduced computational overload since matrix inverse used in MMSE is not necessary.
Author : Xavier Llorens Sole
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (83 download)
Download or read book influence of channel estimation errors in mimo-ofdm systems[ written by Xavier Llorens Sole and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Yong Soo Cho
Publisher : John Wiley & Sons
ISBN 13 : 0470825626
Total Pages : 458 pages
Book Rating : 4.4/5 (78 download)
Download or read book MIMO-OFDM Wireless Communications with MATLAB written by Yong Soo Cho and published by John Wiley & Sons. This book was released on 2010-08-20 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
