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Improved Statistical Interference Suppression Techniques In Single And Multi Rate Direct Sequence Spread Spectrum Code Division Multiple Access Systems
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Book Synopsis Improved Statistical Interference Suppression Techniques in Single and Multi-rate Direct Sequence Spread Spectrum Code Division Multiple Access Systems by : Beibei Wang
Download or read book Improved Statistical Interference Suppression Techniques in Single and Multi-rate Direct Sequence Spread Spectrum Code Division Multiple Access Systems written by Beibei Wang and published by . This book was released on 2007 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: We first present a statistical parallel interference cancellation (STPIC) technique. Here we propose two different methods: instantaneous STPIC (ISTPIC), in which IC is performed only on the bits whose absolute log likelihood ratio (LLR) is below a pre-selected threshold, and block STPIC (BSTPIC), in which IC is performed only on the blocks whose average signal-to-interference-plus-noise-ratio (SINR) is below a pre-selected threshold. Both LLR and SINR statistics reduce to quantities simple to obtain. It has been shown that both ISTPIC and BSTPIC can achieve performance similar to or better than conventional full PIC (FPIC), but with significantly reduced computational complexity. It is also shown that the proposed ISTPIC has larger performance gain than conventional FPIC in higher loading case where efficient interference cancellation techniques are mostly needed. We also propose a new generalized soft limiter (GSL) that combines the advantage of hard decision and partial soft decision. In GSL, hard decisions are made on "reliable" signals with absolute amplitudes larger than a threshold, whereas partial soft decisions are made on "unreliable" signals with absolute amplitudes less than the threshold. We have shown that PIC using the proposed GSL has performance similar to that using hyperbolic tangent decision, which has been shown to be the optimal decision in the single user case with Gaussian interference and noise, but with easier implementation. Furthermore, we propose new techniques that combine the STPIC with partial PIC or other improved decision techniques, which have shown to be capable of achieving performance similar to or better than original techniques with reduced computational complexity. We also evaluate and compare the performance of different PIC techniques in the presence of imperfect channel estimation and near-far effects. Performance analysis and comparison of different PIC techniques have also been done in multi-rate DS-CDMA systems with different schemes: variable spreading gain, multi-code, and variable chip rate. Finally, we review narrowband interference (NBI) suppression techniques and investigate the performance of a decision feedback scheme aided by the proposed GSL-PIC in the presence of NBI.
Book Synopsis Multiple Access Interference Characterization for Direct-Sequence Spread-Spectrum Communications Using Chip Waveform Shaping by : Matthew G. Glen
Download or read book Multiple Access Interference Characterization for Direct-Sequence Spread-Spectrum Communications Using Chip Waveform Shaping written by Matthew G. Glen and published by . This book was released on 2004-03-01 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research characterizes MAI effects on DS/SSMA system performance through simulation in Matlab , and explores the impact of multiple access code selection, chip waveform shaping, and multiple access code length on BER for both synchronous and asynchronous multiple access networks. In addition, the simulated DS/SSMA model permits rapid research into the effects of additional factors on BER. Prior to experimental testing, model validation is conducted through single user trials and by comparison with existing research for similar system designs. For synchronous and asynchronous networks, Gold coding improves BER by 7.5 and 4.0 dB, respectively, relative to aperiodic random spreading codes. Synchronous network results show that chip waveform shaping provides no significant BER improvement for the Blackman or Lanczos shapes. However, asynchronous network results show a potential BER improvement for Blackman and Lanczos shapes. Increasing code length from 31 to 511 resulted in a 7.5 dB BER improvement. Collectively, these results directly relate changes in BER to waveform cross-correlation statistics.
Book Synopsis Interference Characterization and Suppression for Multiuser Direct-sequence Spread-spectrum System by : Mingxi Fan
Download or read book Interference Characterization and Suppression for Multiuser Direct-sequence Spread-spectrum System written by Mingxi Fan and published by . This book was released on 2002 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis we investigate efficient modulation and detection techniques for the uplink (i.e. transmission from mobile to base station) of a DS-CDMA network. Specifically, the thesis contains three parts. In the first part, we focus on the mobile transmitter. In particular, we evaluate and compare the spectral efficiency of two promising variable rate DS-CDMA transmission techniques, multicode (MCD) and variable-spreading-gain (VSG), under the presence of multiple-access (user-to-user) interferences (MAI) and multipath interferences. The uniqueness of our study is that in bit-error-rate evaluation, instead of approximating the interference as Gaussian noise (which has been done in most of the previous studies), we incorporate both power and distribution of interferences into consideration. We show where the Gaussian assumption may give misleading answers and how our results in these cases are different from those obtained in the past. In part two and three of the thesis, we focus on the base station receiver. Specifically, we present effective joint detection techniques that have good performance-complexity tradeoff. Part two of the thesis introduces a class of novel multistage parallel interference cancellation algorithms based on stage-by-stage minimum mean-squared error (MMSE) optimization. We show that this scheme is capable of achieving significantly better performance than other algorithms with similar complexity. Part three of the thesis presents a low-complexity dual-mode multiuser detector that dynamically switches its detection mode between the matched-filter receiver and the decorrelator. We show that this detector is capable of achieving the performance of a decorrelator but with significant savings in processing power and complexity.
Book Synopsis Narrowband and Multiple-Access Interference Suppression for Direct Sequence Spread Spectrum Communication Receivers by : John Doherty
Download or read book Narrowband and Multiple-Access Interference Suppression for Direct Sequence Spread Spectrum Communication Receivers written by John Doherty and published by . This book was released on 1998 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents research results focused on the mitigation of both narrowband and multiple access interference in direct sequence spread spectrum communication systems. Both linear and nonlinear adaptive algorithmic approaches are developed and reported. Specific attention has been paid to making the algorithmic practicable. In addition to the algorithmic development, a software simulation for a code division multiple access system is developed using a commercially available programming environment.
Book Synopsis Electrical & Electronics Abstracts by :
Download or read book Electrical & Electronics Abstracts written by and published by . This book was released on 1997 with total page 2240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Excision Techniques in Direct Sequence Spread Spectrum Communication Systems by :
Download or read book Excision Techniques in Direct Sequence Spread Spectrum Communication Systems written by and published by . This book was released on 1990 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents a comprehensive summary of a number of methods used in filtering narrowband jammers and interference out of direct sequence spread spectrum communication systems. The basic concept is presented first followed by a discussion of several analog techniques for interference suppression. Most of the emphasis is on digital adaptive methods, which rely on adaptive filtering algorithms. Many of these algorithms are highlighted. This is followed by a discussion on the research which has been conducted in digital excision over the past several years. Two cases based on the author's work are also presented. The first details the performance one can expect from the recursive least squares algorithm when the interferer is a stable tone. An analytical model, which predicts the bit error rate performance for the recursive algorithm under certain conditions, is derived. This model is compared to results obtained from computer simulation, the tracking and filtering capabilities of hte block and recursive least square algorithms when the interference is of the FM-type, i.e., a swept tone having a bandwidth which is approximately 20% of the chip rate. (Author).
Book Synopsis The Internet Encyclopedia, Volume 3 (P - Z) by : Hossein Bidgoli
Download or read book The Internet Encyclopedia, Volume 3 (P - Z) written by Hossein Bidgoli and published by John Wiley & Sons. This book was released on 2004-04-12 with total page 979 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Internet Encyclopedia in a 3-volume reference work on the internet as a business tool, IT platform, and communications and commerce medium.
Book Synopsis Handbook of Information Security, Key Concepts, Infrastructure, Standards, and Protocols by : Hossein Bidgoli
Download or read book Handbook of Information Security, Key Concepts, Infrastructure, Standards, and Protocols written by Hossein Bidgoli and published by John Wiley and Sons. This book was released on 2006-03-20 with total page 1122 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Handbook of Information Security is a definitive 3-volume handbook that offers coverage of both established and cutting-edge theories and developments on information and computer security. The text contains 180 articles from over 200 leading experts, providing the benchmark resource for information security, network security, information privacy, and information warfare.
Book Synopsis Multiple Access Interference Suppression for Direct-sequence Code-division Multiple Access (DS-CDMA) Communication Systems by : Wan Shi Chen
Download or read book Multiple Access Interference Suppression for Direct-sequence Code-division Multiple Access (DS-CDMA) Communication Systems written by Wan Shi Chen and published by . This book was released on 1998 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Narrowband Interference Suppression Techniques Using Decision Feedback Filtering in Direct Sequence Spread Spectrum Systems by : Katherine Jauregui Lovette
Download or read book Narrowband Interference Suppression Techniques Using Decision Feedback Filtering in Direct Sequence Spread Spectrum Systems written by Katherine Jauregui Lovette and published by . This book was released on 1994 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Spread Spectrum Techniques by : Robert C. Dixon
Download or read book Spread Spectrum Techniques written by Robert C. Dixon and published by . This book was released on 1976-11-01 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Signal-to-noise-plus-interference Ratio Estimation and Statistics for Direct Sequence Spread Spectrum Code Division Multiple Access Communications by : Amit Gupta
Download or read book Signal-to-noise-plus-interference Ratio Estimation and Statistics for Direct Sequence Spread Spectrum Code Division Multiple Access Communications written by Amit Gupta and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Interference Suppression in Spread Spectrum Code Division Multiple Access Communications by : Leslie Ann Rusch
Download or read book Interference Suppression in Spread Spectrum Code Division Multiple Access Communications written by Leslie Ann Rusch and published by . This book was released on 1994 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Multiple Access Interference Rejection Technique Using Weighted Despreading Functions for Direct-Sequence Code Division Multiple Access Communications by : Yuejin Huang
Download or read book A Multiple Access Interference Rejection Technique Using Weighted Despreading Functions for Direct-Sequence Code Division Multiple Access Communications written by Yuejin Huang 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 Multiple Access Interference Rejection Technique Using Weighted Despreading Functions for Direct-sequence Code Division Multiple Access Communications" by 黃耀進, Yuejin, Huang, 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_b3123707 Subjects: Wireless communication systems Code division multiple access Spread spectrum communications
Book Synopsis Spread Spectrum Communications Handbook, Electronic Edition by : Marvin K. Simon
Download or read book Spread Spectrum Communications Handbook, Electronic Edition written by Marvin K. Simon and published by McGraw Hill Professional. This book was released on 2001-09-22 with total page 1250 pages. Available in PDF, EPUB and Kindle. Book excerpt: The acknowledged Spread-Spectrum Bible the most complete reference in the field! INCLUDESCD-ROM CONTAININGTHE ENTIRE BOOKIN FULLY-SEARCHABLE PDF Spread-spectrum systems have found important commercial applications in CDMA cellular networks and wireless personal communication networks. Communications engineers and technicians now have ready access to a wealth of spread-spectrum information in this exhaustive handbook the most comprehensive and authoritative compendium on spread-spectrum systems available anywhere. Written by recognized authorities in the field, the Handbook presents both theoretical basics and practical applications, providing succinct, results-oriented solutions to engineering problems. Starting with basic concepts and system models, the book covers: Anti-jamming communication systems Coherent direct-sequence systems Non-coherent frequency-hopped systems Coherent and differentially coherent modulation techniques Pseudonoise acquistion and tracking in direct sequence receivers Time and frequency synchronization of frequency-hopped receivers Low probability of intercept communications In addition, it offers an in-depth look at multiple access communications and positioning systems and discusses the growth of spread-spectrum applications. INCLUDES CD-ROM CONTAINING THE ENTIRE BOOK IN FULLY SEARCHABLE PDF
Book Synopsis Adaptive Signal Processing Techniques for Robust, High Capacity Spread- Spectrum Multiple Access by :
Download or read book Adaptive Signal Processing Techniques for Robust, High Capacity Spread- Spectrum Multiple Access written by and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project is concerned with signal processing and coding techniques, which can improve the performance of spread-spectrum multiple-access systems. Specific topics investigated during the course of this project include: (1) Reduced-rank interference suppression; (2) Combined coding and interference suppression, (3) Joint transmitter-receiver optimization in the presence of multiple access interference; and (4) The effect of limited feedback on the performance of joint transmitter-receiver optimization schemes. The theory of large random matrices has been used to analyze the performance of both interference suppression and interference avoidance schemes. For example, we have used these techniques to analyze the performance of adaptive reduced- and full-rank least squares filtering for interference suppression with limited training. This analysis shows the effects of algorithm parameters, which determine the initialization and data windowing, along with system load and noise level. Other contributions include optimization of the ratio of pilot-to-data power and code rate with adaptive linear interference suppression, and signature optimization for combined interference avoidance and pre-equalization of multi-path. Transmitter optimization with limited feedback has also been considered, and bounds on the achievable performance as a function of feedback bits per dimension have been obtained. This project has resulted in a patent application for an adaptive reduced-rank filter, a paper award (for work on reduced-rank filtering), and numerous journal and conference publications on the preceding topics.
Book Synopsis Enhanced Time Domain Interference Suppression Techniques by : Gary J. Saulnier
Download or read book Enhanced Time Domain Interference Suppression Techniques written by Gary J. Saulnier and published by . This book was released on 1998 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many methods have been proposed for suppressing interference in a direct sequence spread spectrum signal and a number of these utilize adaptive transversal suppression filters to remove a large portion of the interference prior to despreading. This report investigates the performance of predictive and two-sided adaptive filtering systems and presents a method to improve the performance of the predictive filter by compensating for the distortion introduced into the desired direct sequence signal during the adaptive filtering process. It is shown that the predictive filter acts as a pre-whitener and the two-sided filter acts as a power inverter. Additionally, the two-sided adaptive filter automatically performs the same function as the compensated predictive filter. The performance of the adaptive systems is also studied when there is multipath propagation and it is shown that the presence of multipath allows the filters to partially suppress the desired direct sequence signal, resulting in performance loss. A combination of simulation and analysis was used to perform this study. Simulations were performed using the Signal Processing Work System (SPW) from Alta Group of Cadence Design Systems, Inc.
