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Independent Component Analysis In Ds Cdma Multiuser Detection And Interference Cancellation
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Book Synopsis Independent Component Analysis in DS-CDMA Multiuser Detection and Interference Cancellation by : Toni Huovinen
Download or read book Independent Component Analysis in DS-CDMA Multiuser Detection and Interference Cancellation written by Toni Huovinen and published by . This book was released on 2008 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Independent Component Analysis and Blind Signal Separation by : Carlos G. Puntonet
Download or read book Independent Component Analysis and Blind Signal Separation written by Carlos G. Puntonet and published by Springer. This book was released on 2004-10-27 with total page 1270 pages. Available in PDF, EPUB and Kindle. Book excerpt: In many situations found both in Nature and in human-built systems, a set of mixed signals is observed (frequently also with noise), and it is of great scientific and technological relevance to be able to isolate or separate them so that the information in each of the signals can be utilized. Blind source separation (BSS) research is one of the more interesting emerging fields now a days in the field of signal processing. It deals with the algorithms that allow the recovery of the original sources from a set of mixtures only. The adjective "blind" is applied because the purpose is to estimate the original sources without any a priori knowledge about either the sources or the mixing system. Most of the models employed in BSS assume the hypothesis about the independence of the original sources. Under this hypothesis, a BSS problem can be considered as a particular case of independent component analysis(ICA), a linear transformation technique that, starting from a multivariate representation of the data, minimizes the statistical dependence between the components of the representation. It can be claimed that most of the advances in ICA have been motivated by the search for solutions to the BSS problem and, the other way around, advances in ICA have been immediately applied to BSS. ICA and BSS algorithms start from a mixture model, whose parameters are estimated from the observed mixtures. Separation is achieved by applying the inverse mixture model to the observed signals(separating or unmixing model). Mixturem- els usually fall into three broad categories: instantaneous linear models, convolutive models and nonlinear models, the?rstone being the simplest but, in general, not near realistic applications. The development and test of the algorithms can be accomplished through synthetic data or with real-world data. Obviously, the most important aim(and most difficult) is the separation of real-world mixtures. BSS and ICA have strong relations also, apart from signal processing, with other fields such as statistics and artificial neural networks. As long as we can find a system that emits signals propagated through a mean, andthosesignalsarereceivedbyasetofsensorsandthereisaninterestinrecovering the original sources, we have a potential field of application for BSS and ICA. Inside that wide range of applications we can find, for instance: noise reduction applications, biomedical applications, audio systems, telecommunications, and many others. This volume comes out just 20 years after the first contributions in ICA and BSS 1 appeared . Therein after, the number of research groups working in ICA and BSS has been constantly growing, so that nowadays we can estimate that far more than 100 groups are researching in these fields. As proof of the recognition among the scientific community of ICA and BSS developments there have been numerous special sessions and special issues in several well- 1 J. Herault, B. Ans, "Circuits neuronaux à synapses modi?ables: décodage de messages composites para apprentissage non supervise", C.R. de l'Académie des Sciences, vol. 299, no. III-13,pp.525-528,1984
Book Synopsis Blind Multiuser Detection for DS-CDMA Using Independent Component Analysis and Prior Knowledge by : David L. Overbye
Download or read book Blind Multiuser Detection for DS-CDMA Using Independent Component Analysis and Prior Knowledge written by David L. Overbye and published by . This book was released on 2004 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Independent Component Analysis and Blind Signal Separation by :
Download or read book Independent Component Analysis and Blind Signal Separation written by and published by . This book was released on 2004 with total page 1308 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Application of Independent Component Analysis to DS-CDMA Detection by :
Download or read book An Application of Independent Component Analysis to DS-CDMA Detection written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Advances in Multiuser Detection by : Michael L. Honig
Download or read book Advances in Multiuser Detection written by Michael L. Honig and published by John Wiley & Sons. This book was released on 2009-08-31 with total page 517 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.
Book Synopsis An Application of PearsonICA to DS-CDMA Detection by : S. D. Parmar
Download or read book An Application of PearsonICA to DS-CDMA Detection written by S. D. Parmar and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Commercial cellular networks, like the systems based on Direct Sequence-Code Division Multiple Access (DS-CDMA), face many types of interferences such as multiuser interference inside each sector in a cell to interoperate interference. While unintentional jamming can be present due to coexisting systems at the same band, intentional jamming arises mainly in military applications. Independent Component Analysis (ICA) has been used as an advanced preprocessing tool for blind suppression of interfering signals in DS-CDMA communication systems. The role of ICA is to provide an interference-mitigated signal to the conventional detection. This paper evaluates the performance of the PearsonICA algorithm to solve the symbol estimation problem of multiusers in a DS-CDMA communication system. The main focus is on blind separation of convolved CDMA mixture and on improvement of the downlink symbol estimation. The results of the numerical experiments are compared with those obtained by the Single User Detection (SUD) receiver, the ICA detector and the combined SUD-ICA detector.
Book Synopsis Multiuser Detection of DS-CDMA Signals Using Parallel Interference Cancellation in Wireless Communications by : Mohsen Ghotbi
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.
Book Synopsis Parallel Interference Cancellation Multiuser Detectors for DS-CDMA Communication Systems by : Feng Liu
Download or read book Parallel Interference Cancellation Multiuser Detectors for DS-CDMA Communication Systems written by Feng Liu and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A nonlinear sub-optimal multiuser detector in the form of parallel interference cancellation (PIC) has been studied. The main objective of this thesis is to develop an analytical model for PIC performance analysis and propose new near-optimum approach. Since the exact performance analysis of PIC is difficult to derive due to its nonlinear decision function, previous work tends to adopt computer simulation method or evaluate through Gaussian approximation (GA) method. For PIC detector, the GA method may not apply since there may exist a dominate interference signal. In addition, the central limit theorem is not applicable to model the residual MAI in the case of PIC due to its own structural property. We develop an analytical model to derive the exact BER performance in the case of two users, and extend the method to approximate cases when moderate-to-high SINR can be encountered. We propose a gradient adaptive parallel interference cancellation detector and investigate its performance. The presented PIC detector is equipped with a set of adaptive weights which are adjusted through a new proposed gradient adaptive step size-LMS (GASS-LMS) algorithm to reduce the cost of wrong interference estimation as existed in the conventional PIC. The initial state is deliberately set based on the function of probability of error to reflect the reliability of the tentative decision from the previous stage. While the most previous work on MUD are restricted to cases where there is no intersymbol interference (ISI), we consider the problem of joint detection of MAI and ISI, which is crucial to enhance the performance of the third and future generation systems with high data rate applications. Simulation results are provided to show that our low complexity joint detector can perform very well, yielding the bit error rate (BER) close to the non-ISI single-user error rate.
Book Synopsis Improved Subtractive Interference Cancellation for DS-CDMA by :
Download or read book Improved Subtractive Interference Cancellation for DS-CDMA written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Third generation wireless systems are being brought into operation rapidly. Multiuser detection is a key technology that can substantially increase the system capacity. Subtractive interference cancellation is a major category of multiuser detection. Due to their lower complexity, subtractive interference cancellation approaches are attractive for the practical implementation of multiuser detection. This thesis begins with a brief study of several multiuser detection techniques followed by an investigation of subtractive interference cancellation techniques. Two basic schemes, successive interference cancellation (SIC) and parallel interference cancellation (PIC) are discussed in detail and other schemes based on these two, a hybrid and a groupwise scheme, are also introduced. Both SIC and PIC have disadvantages. Consequently, a multistage groupwise weighted interference cancellation (MGWIC) scheme that is flexible in practical implementation and has good performance is proposed and analyzed. The analysis and simulation for a simplified case are presented. The implementation and performance under other conditions are also discussed.
Book Synopsis Structures and algorithms for multiuser detection and interference supression in ds-cdma systems by :
Download or read book Structures and algorithms for multiuser detection and interference supression in ds-cdma systems written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Esta tese apresenta novas estruturas e algoritmos para detecção multiusuário e supressão de interferência em sistemas DS-CDMA. São investigadas estruturas baseadas em redes neurais recorrentes para projeto de receptores com decisão realimentada e desenvolvidos algoritmos adaptativospara combater a interferência de múltiplo acesso e a interferência entre símbolos. Novos algoritmos baseados na minimização da taxa de erro de bits são examinados e generalizados para esquemas de detecção com cancelamento de interferência. Para situações onde uma seqüência de treinamento não é disponibilizada, é considerado um novo critério de projeto às cegas de receptores com restrições lineares baseado na função custo módulo constante. Algoritmos adaptativos às cegas baseados neste novo critério são usados para estimar os parâmetros de um receptor linear e do canal decomunicações. São também desenvolvidos novos mecanismos às cegas de ajuste do passo para algoritmos do tipo gradiente estocástico em receptores lineares com base no critério de mínima variância com restrições. Com base nos critérios de mínima variância e módulo constante com restrições, sãodesenvolvidos critérios de projeto às cegas para receptores com decisão realimentada e propostos algoritmos adaptativos para essas estruturas. Um novo esquema de cancelamento sucessivo de interferência baseado no conceito de arbitragem é proposto e incorporado a uma estrutura de recepção com decisão realimentada para o enlace reverso. Em seguida, o novo esquema decancelamento de interferência é combinado com uma estrutura iterativa queemprega múltiplos estágios, resultando em melhores estimativas do receptore um desempenho uniforme para os usuários. Finalmente, são apresentadasnovas estruturas de recepção com posto reduzido, baseadas em filtros FIRinterpolados e interpoladores variantes no tempo, e desenvolvidos algoritmosadaptativos às cegas e supervisionados para o novo esquema.
Book Synopsis The 14th IEEE 2003 International Symposium on Personal, Indoor, and Mobile Radio Communications by : Ke Gong
Download or read book The 14th IEEE 2003 International Symposium on Personal, Indoor, and Mobile Radio Communications written by Ke Gong and published by I E E E. This book was released on 2003 with total page 1066 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Single and Multi-Carrier DS-CDMA by : Lajos L. Hanzo
Download or read book Single and Multi-Carrier DS-CDMA written by Lajos L. Hanzo and published by Wiley-IEEE Press. This book was released on 2003-09-26 with total page 1104 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is dedicated to a range of CDMA and MC-CDMA transmission aspects of systems designed for communicating over fading wireless channels. Currently, a technical in-depth book on this subject, which has a similar detailed exposure of the recent advances in CDMA, M-ary CDMA and MC-CDMA, is unavailable. 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 five main parts: Part I: provides a detailed introduction to the subject of CDMA systems designed for employment in various application Part II: deals with the currently hot topic of genetic algorithm assisted multiuser detection Part III: gives a detailed account of new, reduced-complexity M-ary CDMA schemes Part IV: considers a range of novel MC-CDMA schemes which have the potential of supporting numerous design objectives Part V: provides an overview of the 3G wireless system proposals and characterises the expected network capacity gains attained with the aid of adaptive CDMA systems By providing an all-encompassing self-contained treatment this groundbreaking volume will have appeal to researchers, postgraduate students, academics practising research and development engineers working for wireless communications and computer networking companies, as well as senior undergraduate students and technical managers in the field.
Book Synopsis Digest by : IEEE Antennas and Propagation Society. International Symposium
Download or read book Digest written by IEEE Antennas and Propagation Society. International Symposium and published by . This book was released on 2005 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Multiuser Detection in DSSS Systems by : Shahzadi Mahnoor
Download or read book Multiuser Detection in DSSS Systems written by Shahzadi Mahnoor and published by LAP Lambert Academic Publishing. This book was released on 2014-05-28 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: Direct sequence code division multiple access (DS-CDMA) is a popular wireless technology in DS-CDMA communications, all of the users' signal overlap in time and frequency and cause mutual interference. The capacity of Direct Sequence Code Division Multiple Access (DS-CDMA) is limited by Multiple Access Interference (MAI) instead of thermal noise. Commercial CDMA systems such as the ones based on IS-95 standard regard MAI as additive noise and employ matched filter detectors. This technique limits the number of users that can be supported in DS-CDMA system to less than 10% of the spreading gain. Moreover the bit error rates for individual users degrade rapidly with an increase in number of users. The conventional DS-CDMA detector follows single user detection strategy in which each user is detected separately without regard for the other users. A better strategy is multi-user detection, where information about multiple users is used to improve detection of each individual user. A number of important multiuser detectors have been proposed here. The content of the book is in following sequence.
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.
