Multiple Access Over Time- and Frequency-selective Channels PDF Download

Author: Shengli Zhou
Publisher:
ISBN:
Category :
Languages : en
Pages : 354

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Author: Franz Hlawatsch
Publisher: Academic Press
ISBN: 0080922724
Category : Technology & Engineering
Languages : en
Pages : 457

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Book Description
As a result of higher frequencies and increased user mobility, researchers and systems designers are shifting their focus from time-invariant models to channels that vary within a block. Wireless Communications Over Rapidly Time-Varying Channels explains the latest theoretical advances and practical methods to give an understanding of rapidly time varying channels, together with performance trade-offs and potential performance gains, providing the expertise to develop future wireless systems technology. As well as an overview of the issues of developing wireless systems using time-varying channels, the book gives extensive coverage to methods for estimating and equalizing rapidly time-varying channels, including a discussion of training data optimization, as well as providing models and transceiver methods for time-varying ultra-wideband channels. - An introduction to time-varying channel models gives in a nutshell the important issues of developing wireless systems technology using time-varying channels - Extensive coverage of methods for estimating and equalizing rapidly time-varying channels, including a discussion of training data optimization, enables development of high performance wireless systems - Chapters on transceiver design for OFDM and receiver algorithms for MIMO communication channels over time-varying channels, with an emphasis on modern iterative turbo-style architectures, demonstrates how these important technologies can optimize future wireless systems

Author: Ayman M. Assra
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Supporting the expected high data rates required by wireless Internet and high-speed multimedia services is one of the basic requirements in broadband mobile wireless systems. However, the achievable capacity and data rate of wireless communication systems are limited by the time-varying nature of the channel. Efficient techniques for combating the time-varying effects of wireless channels can be achieved by utilizing different forms of diversity. In recent years, transmit diversity based on space-time coding (STC) has received more attention as an effective technique for combating fading. On the other hand, most existing space-time diversity techniques have been developed for flat-fading channels. Given the fact that wireless channels are generally frequency-selective, in this thesis, we aim to investigate the performance of space-time diversity schemes for wideband code-division multiple-access (WCDMA) systems over frequency-selective fading channels. The proposed receiver in this case is a rake-type receiver, which exploits the path diversity inherent to multipath propagation. Then, a decorrelator detector is used to mitigate the multiple access interference (MAI) and the known near-far problem. We derive the bit error rate (BER) expression over frequency-selective fading channels considering both the fast and slow fading cases. Finally, we show that our proposed receiver achieves the full system diversity through simulation and analytical results. Most of the work conducted in this area considers perfect knowledge of the channel at the receiver. Hence, channel identification brings significant challenges to multiple-input multiple-output (MIMO) CDMA systems. In light of this, we propose a channel estimation and data detection scheme based on the superimposed training-based approach. The proposed scheme enhances the performance by eliminating the MAI from both the channel and data estimates by employing two decorrelators; channel and data decorrelators. The performance of the proposed estimation technique is investigated over frequency-selective slow fading channels where we derived a closed-form expression for the BER as a function of the number of users, K, the number resolvable paths, L, and the number of receive antennas, V . Finally, our proposed scheme is shown to be more robust to channel estimation errors. Furthermore, both the analytical and simulation results indicate that the full system diversity is achieved. Considering that training estimation techniques suffer either from low spectral efficiency (i.e., conventional training approach) or from high pilot power consumption (i.e., superimposed training-based approach), in the last part of the thesis, we present an iterative joint detection and estimation (JDE) using the expectation-maximization (EM) algorithm for MIMO CDMA systems over frequency-selective fading channels. We also derive a closed-form expression for the optimized weight coefficients of the EM algorithm, which was shown to provide significant performance enhancement relative to the conventional equal-weight EM-based signal decomposition. Finally, our simulation results illustrate that the proposed receiver achieves near-optimum performance with modest complexity using very few training symbols.

Author: David Tse
Publisher: Cambridge University Press
ISBN: 9780521845274
Category : Computers
Languages : en
Pages : 598

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Book Description
This textbook takes a unified view of the fundamentals of wireless communication and explains cutting-edge concepts in a simple and intuitive way. An abundant supply of exercises make it ideal for graduate courses in electrical and computer engineering and it will also be of great interest to practising engineers.

Author: Saleh Faruque
Publisher: Springer
ISBN: 3319916513
Category : Technology & Engineering
Languages : en
Pages : 84

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Book Description
This book provides a comprehensive overview of multiple access techniques used in the cellular industry. The usage of multiple access techniques in telecommunications enables many users to share the same spectrum in the frequency domain, time domain, code domain or phase domain. Licenses are given, by the FCC, to operate wireless communication systems over given bands of frequencies, with the smaller bands, (channels), reused to provide services to other users. Thus, bandwidth efficiency is vital, as the speed and size of digital data networks continue to expand. This brief also uses numerous illustrations to bring students up-to-date in the practical applications of multiple access techniques, which can then be put to work in the industry. Primarily, electrical engineering students who study telecommunications, as well as engineers and designers working in wireless communications, would find this book useful.

Author: Tamer Adel Kadous
Publisher:
ISBN:
Category :
Languages : en
Pages : 182

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Author: Tao Jiang
Publisher: CRC Press
ISBN: 1420088254
Category : Computers
Languages : en
Pages : 640

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Book Description
Supported by the expert-level advice of pioneering researchers, Orthogonal Frequency Division Multiple Access Fundamentals and Applications provides a comprehensive and accessible introduction to the foundations and applications of one of the most promising access technologies for current and future wireless networks. It includes authoritative cove

Author: Ezio Biglieri
Publisher: IOS Press
ISBN: 1586037285
Category : Computers
Languages : en
Pages : 360

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Book Description
Surveys general results on multiple-access channels, and gives an overview of the problems of CDMA solutions. This work includes chapters devoted to the information-theoretical aspects of multiple-access communication. It discusses multiple-access techniques and covers coding techniques.

Author: David Edward Borth
Publisher:
ISBN:
Category :
Languages : en
Pages : 366

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Book Description
The performance of biphase direct-sequence spread-spectrum multiple-access (SSMA) communication for a general class of fading channels is investigated. The channels considered are those for which the channel output consists of a strong stable specular signal plus a faded version of this signal. Such channels are the result of a transmission medium which gives rise to a major stable communication path and a number of additional weaker communication paths. The fading channel is modeled as a general is modeled as a general wide-sense-stationary uncorrelated-scattering (WSSUS) channel -- a model which is general enough to exhibit both time and frequency selectivity and to impose no restrictions on the fading rate. A discussion of the important parameters of the WSSUS channel is given and two important classes of WSSUS channels are developed from the general fading channel model; time-selective fading channels and frequency-selective fading channels. In analyzing the performance of direct-sequence SSMA communications via fading channels two measures of system performance that are considered are average signal-to-noise ratio at the receiver output and the average probability of error. (Author).

Author: Dan C. Marinescu
Publisher: Academic Press
ISBN: 0123838754
Category : Mathematics
Languages : en
Pages : 745

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Book Description
A new discipline, Quantum Information Science, has emerged in the last two decades of the twentieth century at the intersection of Physics, Mathematics, and Computer Science. Quantum Information Processing is an application of Quantum Information Science which covers the transformation, storage, and transmission of quantum information; it represents a revolutionary approach to information processing. Classical and Quantum Information covers topics in quantum computing, quantum information theory, and quantum error correction, three important areas of quantum information processing. Quantum information theory and quantum error correction build on the scope, concepts, methodology, and techniques developed in the context of their close relatives, classical information theory and classical error correcting codes. - Presents recent results in quantum computing, quantum information theory, and quantum error correcting codes - Covers both classical and quantum information theory and error correcting codes - The last chapter of the book covers physical implementation of quantum information processing devices - Covers the mathematical formalism and the concepts in Quantum Mechanics critical for understanding the properties and the transformations of quantum information