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Multiple Access Interference Suppression For Direct Sequence Code Division Multiple Access Ds Cdma Communication Systems
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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 Code Division Multiple Access Communications by : Savo G. Glisic
Download or read book Code Division Multiple Access Communications written by Savo G. Glisic and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: Code Division Multiple Access (CDMA) has become one of the main candidates for the next generation of mobile land and satellite communication systems. CDMA is based on spread spectrum techniques, which have been used in military applications for over half a century. Only recently, however, has it been recognised that spread spectrum techniques, combined with some additional steps, can provide higher capacity and better flexibility for the mobile cellular radio communications. Code Division Multiple Access Communications comprises a set of contributions from the most distinguished world scientists in the field. These papers review the basic theory and some of the most important problems related to spread spectrum and CDMA. The topics covered centre on the information theory aspects of CDMA; interference suppression and performance analysis. The material presented in this book summarises the main problems in modern CDMA theory and practice and gives a solid starting point for studying this complex and still challenging field. As such Code Division Multiple Access Communications is essential reading for all researchers and designers working in mobile communication systems and provides an excellent text for a course on the subject.
Book Synopsis Code Division Multiple Access (CDMA) by : R. Michael Buehrer
Download or read book Code Division Multiple Access (CDMA) written by R. Michael Buehrer and published by Morgan & Claypool Publishers. This book was released on 2006 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the basic aspects of Code Division Multiple Access or CDMA. It begins with an introduction to the basic ideas behind fixed and random access systems in order to demonstrate the difference between CDMA and the more widely understood TDMA, FDMA or CSMA. Secondly, a review of basic spread spectrum techniques are presented which are used in CDMA systems including direct sequence, frequency-hopping and time-hopping approaches. The basic concept of CDMA is presented, followed by the four basic principles of CDMA systems that impact their performance: interference averaging, universal frequency reuse, soft handoff, and statistical multiplexing. The focus of the discussion will then shift to applications. The most common application of CDMA currently is cellular systems. A detailed discussion on cellular voice systems based on CDMA, specifically IS-95, is presented. The capacity of such systems will be examined as well as performance enhancement techniques such as coding and spatial filtering. Also discussed are Third Generation CDMA cellular systems and how they differ from Second Generation systems. A second application of CDMA that is covered is spread spectrum packet radio networks. Finally, there is an examination of multi-user detection and interference cancellation and how such techniques impact CDMA networks. This book should be of interest and value to engineers, advanced students, and researchers in communications.
Book Synopsis Frequency-Domain Multiuser Detection for CDMA Systems by : Paulo Silva
Download or read book Frequency-Domain Multiuser Detection for CDMA Systems written by Paulo Silva and published by CRC Press. This book was released on 2022-09-01 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Future broadband wireless communication systems are expected to be able to offer new and powerful services enabling fast transmission rates of several tens of Mbit/s. This is an ambitious challenge especially for mobile communication systems since these systems should be able to cope with severely time dispersive channels, associated to the signal multipath propagation. Moreover, these systems should have high spectral and power efficiencies, as well as high capacity and flexibility. Spread spectrum techniques, particularly coded division multiple access (CDMA) techniques allow high capacity and flexibility, continuous transmission requiring low-peak power requirements for the amplifiers, as well as some robustness against fading and time-dispersion effects associated with the multipath propagation. When employed in prefix assisted (PA) block transmission schemes combined with frequency-domain receiver implementations they become especially interesting for broadband wireless systems. 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. The main goal is the study of frequency-domain multiuser detection techniques with iterative signal detection/decoding techniques, also in combination with estimation and cancelation of nonlinear distortion effects. The receiver structures are suitable to scenarios with high interference levels and strongly time-dispersive channels.
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 Large System Performance of Linear Interference Suppression for DS-CDMA. by : Weimin Xiao
Download or read book Large System Performance of Linear Interference Suppression for DS-CDMA. written by Weimin Xiao and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The performance of linear filtering is studied for the suppression of multiple access interference in a Direct-Sequence Code-Division Multiple Access (DS-CDMA) system with random spreading sequences. Both full-rank and reduced-rank filters are investigated. The emphasis of our study is on large system performance analysis.
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781720659761 Total Pages :40 pages Book Rating :4.6/5 (597 download)
Book Synopsis Performance Analysis of Direct-Sequence Code-Division Multiple-Access Communications with Asymmetric Quadrature Phase-Shift-Keying Modulation by : National Aeronautics and Space Administration (NASA)
Download or read book Performance Analysis of Direct-Sequence Code-Division Multiple-Access Communications with Asymmetric Quadrature Phase-Shift-Keying Modulation written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-04 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: This article considers a quaternary direct-sequence code-division multiple-access (DS-CDMA) communication system with asymmetric quadrature phase-shift-keying (AQPSK) modulation for unequal error protection (UEP) capability. Both time synchronous and asynchronous cases are investigated. An expression for the probability distribution of the multiple-access interference is derived. The exact bit-error performance and the approximate performance using a Gaussian approximation and random signature sequences are evaluated by extending the techniques used for uniform quadrature phase-shift-keying (QPSK) and binary phase-shift-keying (BPSK) DS-CDMA systems. Finally, a general system model with unequal user power and the near-far problem is considered and analyzed. The results show that, for a system with UEP capability, the less protected data bits are more sensitive to the near-far effect that occurs in a multiple-access environment than are the more protected bits.Wang, C.-W. and Stark, W.Jet Propulsion LaboratoryQUADRATURE PHASE SHIFT KEYING; BINARY PHASE SHIFT KEYING; ASYMMETRY; CODE DIVISION MULTIPLE ACCESS; PHASE SHIFT KEYING; MULTIPLE ACCESS; PROTECTION; RELIABILITY ANALYSIS
Book Synopsis Adaptive Direct Sequence Code Division Multiple Access (DS-CDMA) Systems Based on Sequence Optimization by : Li Gao
Download or read book Adaptive Direct Sequence Code Division Multiple Access (DS-CDMA) Systems Based on Sequence Optimization written by Li Gao and published by . This book was released on 2002 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book הגמדים written by and published by . This book was released on 1930 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Basics of Code Division Multiple Access (CDMA) by : Raghuveer M. Rao
Download or read book Basics of Code Division Multiple Access (CDMA) written by Raghuveer M. Rao and published by SPIE Press. This book was released on 2005 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Code division multiple access (CDMA) has proven to be a viable enabling technique for the simultaneous transmission and reception of data over a shared channel. Although associated mostly with wireless cellular communication, CDMA is also being considered for optical channels. This text, aimed at the reader with a basic background in electrical or optical engineering, covers CDMA fundamentals: from the basics of the communication process and digital data transmission, to the concepts of code division multiplexing, direct sequence spreading, diversity techniques, the near-far effect, and the IS-95 CDMA standard form.
Book Synopsis Interference Suppression in Spread-spectrum Networks by : Haichang Sui
Download or read book Interference Suppression in Spread-spectrum Networks written by Haichang Sui and published by . This book was released on 2007 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, interference suppression techniques and applications will be presented for cellular networks with direct-sequence (DS) CDMA and mobile ad hoc networks with frequency-hopped (FH) CDMA. The first part of the dissertation focuses on three novel finger placement designs that effectively equalize the DS-CDMA multi- path downlink channel to restore code orthogonality and consequently suppress multiple-access interference. For typical multipath channel models, the proposed schemes may significantly outperform the uniformly spaced tapped-delay-line equalizer with much less fingers/taps. In addition, analytic insight into the effect of the finger number and the smoothness of the chip pulse are obtained. The second part of the dissertation considers mobile ad hoc networks with FH-CDMA, where error-correcting codes are employed with differential unitary space-time modulation. The use of multiple transmit antennas in FH-CDMA systems, to the best knowledge of the author, has not been proposed in previous literature. The proposed receiver performs decision-feedback demodulation, decision-aided adaptive estimation, and erasure-insertion decoding jointly to suppress arbitrary unknown interference without channel state information. The third part of the dissertation presents network performance analysis for FH-CDMA networks with the proposed transceiver. Information efficiency and transmission range optimization is investigated under realistic time-varying channel models, which extends previous studies based on static channels and/or simplistic physical layer models. Impacts of various design parameters and channel properties on the network performance are revealed. The results also provide guidance on optimizing the modulation and coding scheme from a network perspective.
Book Synopsis Transmitter-Based Multiple Access Interference Rejection and Diversity Techniques for Code-Division Multiple Access Systems by : Jia Liu
Download or read book Transmitter-Based Multiple Access Interference Rejection and Diversity Techniques for Code-Division Multiple Access Systems written by Jia Liu and published by . This book was released on 2005 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: Keywords: transmit diversity, multiuser detection, CDMA, multiple access interference, multiuser precoding.
Book Synopsis Design of Interference cancellation Receiver for CDMA with MIMO system by : Dr.P.Sreesudha,
Download or read book Design of Interference cancellation Receiver for CDMA with MIMO system written by Dr.P.Sreesudha, and published by Archers & Elevators Publishing House. This book was released on with total page 73 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Adaptive Receivers for Wireless Direct-sequence Code-division-multiple-access (DS-CDMA) Cellular Communications Systems by : Fernando J. Lombardo
Download or read book Adaptive Receivers for Wireless Direct-sequence Code-division-multiple-access (DS-CDMA) Cellular Communications Systems written by Fernando J. Lombardo and published by . This book was released on 1997 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Multi-user Detection for Multi-rate DS/CDMA Systems by : Jinwen Ma
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.
Book Synopsis Interference Suppression for DS/CDMA Systems in Non-Gaussian Impulsive Channels by : Seoyoung Lee
Download or read book Interference Suppression for DS/CDMA Systems in Non-Gaussian Impulsive Channels written by Seoyoung Lee and published by . This book was released on 1998 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: Simulation results show that the proposed detector provides remarkable performance improvements over the adaptive MD detector in a wide range of near-far situations. The proposed detector has much better near-far resistance than the adaptive MD detector. Finally, fuzzy hybrid detector combines the adaptive MD detector and the hard-limiting matched filter (HLMF) detector. The HLMF detector performs well when the additive impulsive noise significantly dominates over MAI. Simulation results indicate significant performance improvements over the adaptive MD detector alone in impulsive noise-limited environments. When MAI dominates, the fuzzy hybrid detector nearly has the same performance as the adaptive MD detector.
