Combined Multiuser Detection and Adaptive Blind Array Processing for DS-CDMA Systems

Combined Multiuser Detection and Adaptive Blind Array Processing for DS-CDMA Systems
Author: Shahrokh Nayeb Nazar
Publisher:
Total Pages: 0
Release: 2002
Genre: Array processors
ISBN:

The work begins with a study of several most frequently referred to sub-optimal multiuser receivers. The four structures of interest are the decorrelator, the minimum mean square error receiver, the multistage parallel interference cancellation receiver, and the successive interference cancellation receiver. The performance of the receiver structures is compared through simulation studies on the basis of bit error rate in additive white Gaussian noise, and near-far channels. In the second part of this research, array processing techniques are investigated as a means for improving the performance. We evaluate the system performance of some of the existing adaptive blind array schemes for CDMA receivers, and a new adaptive blind algorithm is derived. The knowledge of the desired user's signature sequence is exploited to design the blind receiver, where no training sequence needs to be transmitted. The blind algorithm is formulated using a constrained energy minimization criterion, and adaptation is carried out by using the LMS algorithm combined with the gradient-projection algorithm to incorporate the quadratic constraint. The multiple access interference coming from the directions other than that of the desired user can be significantly suppressed by using spatial filtering property of antenna arrays. The interference rejection capability of the proposed receiver is examined in situations where a single interferer dominates the received power. It is shown that this combination can significantly improve the system performance and outperform all existing multiuser detectors as well as smart antenna systems. Finally, we present a new structure combining two-dimensional RAKE receiver and the multiuser detection for further enhancement of the system performance in multipath fading channels.

CDMA Techniques for Third Generation Mobile Systems

CDMA Techniques for Third Generation Mobile Systems
Author: Francis Swarts
Publisher: Springer Science & Business Media
Total Pages: 324
Release: 2012-12-06
Genre: Technology & Engineering
ISBN: 146155103X

CDMA Techniques for Third Generation Mobile Systems presents advanced techniques for analyzing and developing third generation mobile telecommunication systems. Coverage includes analysis of CDMA-based systems, multi-user receivers, Turbo coding for mobile radio applications, spatial and temporal processing techniques as well as software radio techniques. Special emphasis has been given to recent advances in coding techniques, smart antenna systems, spatial filtering, and software implementation issues. Internationally recognized specialists contributed to this volume, and each chapter has been reviewed and edited for uniformity. CDMA Techniques for Third Generation Mobile Systems is an invaluable reference work for engineers and researchers involved in the development of specific CDMA systems.

Advanced Wireless Communications

Advanced Wireless Communications
Author: Savo G. Glisic
Publisher: John Wiley & Sons
Total Pages: 890
Release: 2007-06-13
Genre: Technology & Engineering
ISBN: 9780470512876

Fully revised and updated version of the successful "AdvancedWireless Communications" Wireless communications continue to attract the attention ofboth research community and industry. Since the first edition waspublished significant research and industry activities have broughtthe fourth generation (4G) of wireless communications systemscloser to implementation and standardization. "Advanced Wireless Communications" continues to provide acomparative study of enabling technologies for 4G. This secondedition has been revised and updated and now includes additionalinformation on the components of common air interface, includingthe area of space time coding , multicarrier modulation especiallyOFDM, MIMO, cognitive radio and cooperative transmission. Ideal for students and engineers in research and development inthe field of wireless communications, the second edition ofAdvanced Wireless Communications also gives an understanding tocurrent approaches for engineers in telecomm operators, governmentand regulatory institutions. New features include: Brand new chapter covering linear precoding in MIMO channelsbased on convex optimization theory. Material based on game theory modelling encompassing problemsof adjacent cell interference, flexible spectra sharing andcooperation between the nodes in ad hoc networks. Presents and discusses the latest schemes for interferencesuppression in ultra wide band (UWB) cognitive systems. Discusses the cooperative transmission and more details onpositioning.

On the Adaptive Multi-stage Detector for Cancellation of Multiuser Interference in CDMA Wireless Communication Systems

On the Adaptive Multi-stage Detector for Cancellation of Multiuser Interference in CDMA Wireless Communication Systems
Author: Nadir Sezgin
Publisher:
Total Pages: 168
Release: 1996
Genre: Data compression (Computer science)
ISBN:

The classical multiple access techniques such as Frequency Division Multiple Access (FDMA) and Time Division Multiple Access (TDMA) schemes are band limited in terms of their capacity to be used for mobile radio communication. Recent developments in the area of digital signal processing, makes Code Division Multiple Access (CDMA) as a possible solution to the demand of capacity for the mobile radio communication. The capacity of CDMA is limited by multiuser interference, that is the interference from the other users. The goal of this dissertation is to improve the multiuser CDMA detector with high Bit Error Rate (BER) performance, low complexity, near-fax resistance as well as flexibility to be applied to a wide range of communication channels. We developed an adaptive multi-stage CDMA detector to cancel the multiuser interference. The first-stage of the detector, called decorrelating detector, decorrelates the correlated signals obtained at the match filter bank. The second-stage, called canceller, cancels the multiuser interference exist in the desired signals, using the decorrelated user signals obtained at the decorrelating detector output. The key future of this multi-stage detector is being purely adaptive. The combination of adaptive decorrelating detector and adaptive canceller allows the multi-stage detector achieve near-optimum BER performance and at the same time remain computationally effective. To increse achievable BElT performance an adaptive soft limiter is used at the canceller stage. The underlying structure of this multi-stage detector (i.e. being purely adaptive) allows it to be applied to different channel characteristics. However, throughout this dissertation we use Additive White Gaussian Noise (AWG N) channel for simplicity. To address some of the potential problems that may arise in practice, the adaptive decorrelating detector is tested using computer simulation and in-depth analysis of the problem. If necessary, an alternative solution that do not change the main characteristics of the detector (such as adaptivity and simplicity) is provided. Overall, we conclude that our adaptive detector with its high BER performance and adaptation ability to different channel characteristics, can be considered as an alternative solution to the problem of multiuser interference cancellation in CDMA communication.

Multiuser Detection in CDMA Mobile Terminals

Multiuser Detection in CDMA Mobile Terminals
Author: Piero Castoldi
Publisher: Artech House
Total Pages: 235
Release: 2002
Genre: Technology
ISBN: 1580533302

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.

Advanced Wireless Communications and Internet

Advanced Wireless Communications and Internet
Author: Savo G. Glisic
Publisher: John Wiley & Sons
Total Pages: 1025
Release: 2011-05-03
Genre: Technology & Engineering
ISBN: 1119991757

ADVANCED WIRELESS COMMUNICATIONS AND INTERNET THIRD EDITION ADVANCED WIRELESS COMMUNICATIONS AND INTERNET Future Evolving Technologies The new edition of Advanced Wireless Communications: 4G Cognitive and Cooperative Broadband Technology, 2nd Edition, including the latest developments In the evolution of wireless communications, the dominant challenges are in the areas of networking and their integration with the Future Internet. Even the classical concept of cellular networks is changing and new technologies are evolving to replace it. To reflect these new trends, Advanced Wireless Communications & INTERNET builds upon the previous volumes, enhancing the existing chapters, and including a number of new topics. Systematically guiding readers from the fundamentals through to advanced areas, each chapter begins with an introductory explanation of the basic problems and solutions followed with an analytical treatment in greater detail. The most important aspects of new emerging technologies in wireless communications are comprehensively covered including: next generation Internet; cloud computing and network virtualization; economics of utility computing and wireless grids and clouds. This gives readers an essential understanding of the overall environment in which future wireless networks will be operating. Furthermore, a number of methodologies for maintaining the network connectivity, by using tools ranging from genetic algorithms to stochastic geometry and random graphs theory, and a discussion on percolation and connectivity, are also offered. The book includes a chapter on network formation games, covering the general models, knowledge based network formation games, and coalition games in wireless ad hoc networks. Illustrates points throughout using real-life case studies drawn from the author’s extensive international experience in the field of telecommunications Fully updated to include the latest developments, key topics covered include: advanced routing and network coding; network stability control; relay-assisted Wireless Networks; multicommodity flow optimization problems, flow optimization in heterogeneous networks, and dynamic resource allocation in computing clouds Methodically guides readers through each topic from basic to advanced areas Focuses on system elements that provide adaptability and re-configurability, and discusses how these features can improve wireless communications system performance Enjoyed this book? Why not tell others about it and write a review on your favourite online bookseller.