Download or read book Subspace Multiuser Detection in DS CDMA Communication Systems and Its Applications written by Yong-Suk Moon and published by . This book was released on 1999 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Frequency domain Multiuser Detection for CDMA Systems written by Paulo Silva and published by River Publishers. This book was released on 2012 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Frequency-Domain Multiuser Detection for CDMA Systems the use of PA block transmission is considered in the context of both DS (Direct Sequence) and MC (Multicarrier) CDMA schemes.
Download or read book Advances in Multiuser Detection written by Michael L. Honig and published by John Wiley & Sons. This book was released on 2009-08-19 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Timely Exploration of Multiuser Detection in Wireless Networks During the past decade, the design and development of current and emerging wireless systems have motivated many important advances in multiuser detection. This book fills an important need by providing a comprehensive overview of crucial recent developments that have occurred in this active research area. Each chapter is contributed by noted experts and is meant to serve as a self-contained treatment of the topic. Coverage includes: Linear and decision feedback methods Iterative multiuser detection and decoding Multiuser detection in the presence of channel impairments Performance analysis with random signatures and channels Joint detection methods for MIMO channels Interference avoidance methods at the transmitter Transmitter precoding methods for the MIMO downlink This book is an ideal entry point for exploring ongoing research in multiuser detection and for learning about the field's existing unsolved problems and issues. It is a valuable resource for researchers, engineers, and graduate students who are involved in the area of digital communications.
Download or read book Multiuser Detection in CDMA Mobile Terminals written by Piero Castoldi and published by Artech House. This book was released on 2002 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here's an authoritative, cutting-edge resource that gives you a thorough understanding of CDMA transmission and detection. It offers practical guidance in designing interference-reducing multi-user receivers for mobile radio systems and multi-user adaptive modems for accessing satellite earth stations. The book provides in-depth descriptions of CDMA principles, and of linear and non-linear multi-user detection , and covers the fine details of the realization of a linear multi-user receiver.
Download or read book Subspace based Methods for Blind Multiuser Detection of DS CDMA Signals written by Joachim Dahl and published by . This book was released on 2000 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Multiuser detection for DS CDMA systems using optimization methods written by Xianmin Wang (Ph. D.) and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Several new multiuser detectors are developed for different direct-sequence codedivision multiple-access (DS-CDMA) application environments. The first detector is based on a semidefinite-programming (SDP) relaxation technique. In this detector, maximum likelihood (ML) detection is achieved by 'relaxing' the associated combinatorial problem into an SDP problem, which leads to a detector of polynomial complexity. It is shown that the SDP-relaxation (SDPR) based detector can be obtained by solving a dual SDP problem which leads to improved efficiency. Computer simulations demonstrate that the SDPR detector offers near-optimal performance with much reduced computational complexity compared with that of the ML detector proposed by Verdu for both synchronous and asynchronous DS-CDMA systems. The second detector is based on a recursive convex programming (RCP) approach. In this detector, ML detection is carried out in two steps: first, the combinatorial problem associated with ML detection is relaxed to a convex programming problem, and then a recursive approach is used to obtain an approximate solution for ML detection. Efficient unconstrained relaxation approach is proposed for the proposed detector to reduce the involved computational complexity. Computer simulations demonstrate that the proposed detectors offer near-optimal detection performance which is superior to that offered by many other suboptimal detectors including the SDPR detector. However, the computational complexity involved in the proposed detectors is much lower relative to that involved in Verdu's ML detector as well as our SDPR detector. The third detector entails a subspace estimation-based constrained optimization approach for channel estimation in DS-CDMA systems with multipath propagation channels. The proposed approach offers an improved approximation for the noise iii subspace compared with that offered by several existing algorithms. Computer simulations show that the performance of the proposed detector offers nearly the same performance as that of existing subspace detectors but leads to a significant reduction in the amount of computation. Relative to some existing constrained optimization methods, the proposed detector offers a significantly improved performance while requiring a comparable amount of computation. The fourth detector is proposed based on a vector constant-modulus (VCM) approach. This detector is designed for DS-CDMA systems with multipath propagation channels where the effective signatures observed at receiver are distorted by multipath propagation and aliasing concurrently. In this detector, detection is carried out by solving a linear constrained optimization problem whose objective function is formulated based on the VCM criterion. Two adaptation algorithms, namely, the constrained stochastic gradient algorithm and the recursive vector constant-modulus algorithm, are developed. Analysis are presented to investigate the performance of the proposed detector. Computer simulations show that the proposed detectors are able to suppress multiuser interference and inter-symbol interference effectively. More importantly, they offer robust detection performance against the effective signature distortion caused by aliasing at the receiver.
Download or read book A Study of Multiuser Detection Algorithms for DS Cdma Communications written by 陳特彬 and published by . This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "A Study of Multiuser Detection Algorithms for DS-CDMA Communications" by 陳特彬, Tak-pun, Chan, 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_b3121498 Subjects: Signal detection Code division multiple access
Download or read book Code aided Multiuser Detection in Multiple Access Wireless Communication Systems written by Ping Liu and published by . This book was released on 2004 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Multiuser Detection for CDMA Communication Systems written by Neeraj R. Deshmukh and published by . This book was released on 2005 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coordinated Multiuser Communications written by CHRISTIAN SCHLEGEL and published by Springer Science & Business Media. This book was released on 2006-07-10 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coordinated Multiuser Communications provides for the first time a unified treatment of multiuser detection and multiuser decoding in a single volume. Many communications systems, such as cellular mobile radio and wireless local area networks, are subject to multiple-access interference, caused by a multitude of users sharing a common transmission medium. The performance of receiver systems in such cases can be greatly improved by the application of joint detection and decoding methods. Multiuser detection and decoding not only improve system reliability and capacity, they also simplify the problem of resource allocation. Coordinated Multiuser Communications provides the reader with tools for the design and analysis of joint detection and joint decoding methods. These methods are developed within a unified framework of linear multiple-access channels, which includes code-division multiple-access, multiple antenna channels and orthogonal frequency division multiple access. Emphasis is placed on practical implementation aspects and modern iterative processing techniques for systems both with, and without integrated error control coding. Focusing on the theory and practice of unifying accessing and transmission aspects of communications, this book is a valuable reference for students, researchers and practicing engineers.
Download or read book Multiuser Detection and Channel Estimation for DS CDMA Systems written by Alexander Lampe and published by . This book was released on 2003 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Multiuser Detection of DS CDMA Signals Using Parallel Interference Cancellation in Wireless Communications written by Mohsen Ghotbi and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a limited network resource, techniques are needed to share the channel among different users as efficiently and as fairly as possible. Among multiple access techniques; Code Division Multiple Access (CDMA) has the exclusive advantage of allowing all active users share the same channel concurrently. When CDMA technique is used, Multi User Detection (MUD) is needed to reject or reduce the Multiple Access Interference (MAI) affecting each active user. In this thesis, it is shown that multiuser detection using Parallel Interference Cancellation (PIC) technique provides a good compromise among the complexity, latency, and performance. This technique is suitable for Digital Video Broadcasting-Return Channel via Satellite (DVB-RSC) as well as Base Station (BS) in cellular communication systems. We offer a new scheme that is a combination of soft and hard PIC detectors whose performance is superior to that of the other famous sub-optimal detectors. For most MUD schemes, a perfect knowledge of users' parameters is required. In this thesis, we apply a very simple method to estimate the parameters. PIC detectors are usually studied in equal-power case, i.e., a perfect power control scheme is assumed. We study PIC detector in near-far condition as well, where users arrive at receiver with different power levels. It is shown that our proposed scheme has some advantages over other schemes. First, it is much less complex than optimal and linear detectors. Second, it is much faster than sequential detector. Third, it has better performance than that of linear detectors.
Download or read book A Study of Multiuser Detection Algorithms for DS CDMA Communications written by Tak-pun Chan and published by . This book was released on 1997 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Multiuser detection in DS CDMA communications written by Zhiqiang Liu and published by . This book was released on 1997 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Multiuser Detection written by Sergio Verdú and published by Cambridge University Press. This book was released on 2011-07-21 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiuser Detection provides the first comprehensive treatment of the subject of multiuser digital communications. Multiuser detection deals with demodulation of the mutually interfering digital streams of information that occur in areas such as wireless communications, high-speed data transmission, satellite communication, digital television, and magnetic recording. The development of multiuser detection techniques is one of the most important recent advances in communications technology, and this self-contained book gives a comprehensive coverage of the design and analysis of receivers for multiaccess channels, while focusing on fundamental models and algorithms. The author begins with a review of multiaccess communications, dealing in particular with code division multiple access (CDMA) channels. Background material on hypothesis testing and the effect of multiuser interference on single-user receivers are discussed next. This is followed by the design and analysis of optimum and linear multiuser detectors. Also covered in detail are topics such as decision-driven multiuser detection and noncoherent multiuser detection. The elements of multiuser detection are clearly and systematically presented along with more advanced recent results, some of which are published here for the first time. The extensive set of references and bibliographical notes offer a comprehensive account of the state of the art in the subject. The only prerequisites assumed are undergraduate-level probability, linear algebra, and introductory digital communications. The book contains over 300 exercises and is a suitable textbook for practicing engineers, as well as a valuable reference volume for researchers in communications and signal processing.
Download or read book Multi user Detection for Multi rate DS CDMA Systems written by Jinwen Ma and published by . This book was released on 2000 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wireless cellular communication is witnessing a rapid growth in market, technology and range of services. Current and future demands for wireless communication services motivate the need for handling multi-media traffic types. In a multimedia communication system, users with different and even time-varying rates and quality of services (QoS) requirements, such as voice, image and data, must be accommodated. The use of Spread Spectrum modulation with Code Division Multiple Access (CDMA) technology is an attractive approach for economical spectrally efficient and high quality cellular and personal communication services. This dissertation explores the technologies of applying different interference cancellation techniques to multi-rate CDMA systems that serve users with different QoS. Multiple Access Interference (MAI) and multipath propagation are the major issues in wireless communication systems. It is also true for multi-rate CDMA systems. Multi-user detection has been shown to be effective in combating the near-far problem and providing superior performance over conventional detection method. In this dissertation, we combine both linear minimum mean squared error (LMMSE) detector, nonlinear decision feedback detector, with other signal processing techniques, such as array processing and multipath combining, to create effective near-far resistant detectors for multi-rate CDMA systems. Firstly, we propose MMSE receivers for synchronous multi-rate CDMA system and compare the performance with the corresponding multi-rate decorrelating detectors. The multi-rate decorrelating detector is optimally near-far resistant and easy to implement. The proposed linear MMSE multi-rate receiver can be adaptively implemented only with the knowledge of the desired user. Due to the fact that MMSE detector offers best trade-off between the MAI cancellation and noise variance enhancement, it is shown that multi-rate MMSE receiver can offer better performance than the multi-rate decorrelator when the interfering users' Signal to Noise Ratio (SNR) is relatively low comparing to the desired user's SNR. Secondly, the asynchronous multi-rate CDMA system, we propose multi-rate multi-shoot decorrelating detectors and multi-rate multi-shot MMSE detectors. The performance of multi-shot detectors can be improved monotonically with increasing the number of stacked bits, but a great computational complexity is going to be introduced in order to get better performance. A debiasing method is introduced to multi-rate multi-shot linear detectors. Debiasing method optimizes multi-rate detectors based on the multi-rate multi-shot model. Debiasing multi-shot MMSE detector for multi-rate signals can offer performance than the corresponding debiasing multi-shot decorrelating detector. Thirdly, we propose linear space-time receivers for multi-rate CDMA systems. The minimum mean-squared error criteria is used. We perform a comparative study on the multi-rate receiver which uses either multipath (temporal) processing or array (spatial) processing, and the one which uses both array and multipath (space-time) processing. The space-time receiver for the multi-rate CDMA signals give us the potential of improving the capacity of multi-rate systems. The space-time processing combined with multiuser detection have the advantages of combating multipath fading through temporal processing, reducing MAI through MMSE method and provide antenna or diversity gain through spatial processing and increasing the capacity of the multi-rate CDMA systems. Lastly, the group-wise interference cancellation methods are proposed for multi-rate CDMA signals. The non-linear decision feedback detection (DFD) schemes are used in the proposed receivers. The proposed interference cancellation schemes benefit from the nature of the unequal received amplitudes for multi-rate CDMA signals. Users with same data rate are grouped together. Users with the highest data-rate are detected first. Interference between the groups is cancelled in a successive order. The results show that the group-wise MMSE DFD yields better performance than multi-rate linear MMSE detector and multi-rate decorrelating detector, especially for highly loaded CDMA systems.
Download or read book New Channel Estimation and Multiuser Detection Algorithms for Multicarrier mc Cdma Communications Systems written by Hui Cheng and published by . This book was released on 2017-01-26 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "New Channel Estimation and Multiuser Detection Algorithms for Multicarrier(MC)-CDMA Communications Systems" by Hui, Cheng, 成慧, 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. Abstract: Abstract of the thesis entitled New Channel Estimation and Multiuser Detection Algorithms For Multicarrier (MC)-CDMA Communications Systems submitted by Cheng Hui for the degree of Doctor of Philosophy at the University of Hong Kong in September 2005 Multicarrier code division multiple access (MC-CDMA) has been recently proposed as an efficient multicarrier transmission scheme for supporting multiple access communications. However, MC-CDMA is an interference-limited system, which is rather sensitive to multiple access interference (MAI). Multiuser detection techniques are critical to mitigate MAI. Meanwhile, channel estimation is essential to the coherent detection of MC-CDMA signals. This thesis is dedicated to new channel estimation and multiuser detection algorithms for wireless MC-CDMA systems. New blind constrained minimum output energy (CMOE)-based and subspace-based multiuser detection and channel estimation algorithms are first developed. In particular, a new blind CMOE receiver is proposed. The proposed CMOE receiver is based on recursive least square (RLS) updating, and it minimizes the receiver''s output energy while preserving the components of the desired signal. iiiBy imposing quadratic weight constraint, the CMOE detector is made more robust against the channel and correlation matrix estimation errors, and a better performance over the standard CMOE detector is obtained. The steady-state signal-to-interference-plus-noise ratio (SINR) performance of the blind adaptive CMOE and training adaptive minimum mean squared-error (MMSE) detectors is also analyzed. A blind mode decision-directed MMSE detector is then proposed to further improve the performance of the blind CMOE receivers. Simulation results show that the blind mode decision-directed MMSE detector substantially improves the system performance when the frequency-selective channel is slowly varying. Blind and group-blind subspace-based MMSE multiuser detectors are also developed, where the channel coefficients can be blindly estimated. The proposed group-blind multiuser detector considerably outperforms the blind subspace-based method in uplink MC-CDMA channels. It exploits the spreading codes of a group of known users within the cell, while suppressing the unknown interferers from other cells using the MMSE principle. The adaptive implementation of the blind and group-blind multiuser detectors is also studied based on signal and noise subspace tracking algorithms. Numerical simulations show that the convergence of the projection approximation subspace tracking with deflation (PASTd) algorithm is quite slow, while the more complicated bi-iteration square-root singular value decomposition (Bi-SVD) signal subspace tracker presents performance close to the solution with exact singular value decomposition (SVD). MC-CDMA systems are sensitive to narrowband interference (NBI). A new robust channel estimator and a robust multiuser detector are developed to combat time-varying NBI. In particular, an efficient weighted recursive least M-estimate (WRLM) algorithm is proposed to recursively estimate the frequency-selective ivfading channel while providing improved robustness to the time-varying NBI. Furthermore, a weighted least M-estimate (WLM) detector is developed to jointly suppress MAI and time-varying NBI. Simulations show that the proposed robust channel estimator and multiuser d