Low Complexity Block Processing Algorithms for Robust Adaptive Channel Estimation in OFDM Systems PDF Download

Author: Christian Rohde
Publisher:
ISBN: 9783844024081
Category :
Languages : en
Pages : 258

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Author: Ayman ElNashar
Publisher: John Wiley & Sons
ISBN: 1118938224
Category : Technology & Engineering
Languages : en
Pages : 396

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Book Description
This book presents an alternative and simplified approaches for the robust adaptive detection and beamforming in wireless communications. It adopts several systems models including DS/CDMA, OFDM/MIMO with antenna array, and general antenna arrays beamforming model. It presents and analyzes recently developed detection and beamforming algorithms with an emphasis on robustness. In addition, simplified and efficient robust adaptive detection and beamforming techniques are presented and compared with exiting techniques. Practical examples based on the above systems models are provided to exemplify the developed detectors and beamforming algorithms. Moreover, the developed techniques are implemented using MATLAB—and the relevant MATLAB scripts are provided to help the readers to develop and analyze the presented algorithms. em style="mso-bidi-font-style: normal;"Simplified Robust Adaptive Detection and Beamforming for Wireless Communications starts by introducing readers to adaptive signal processing and robust adaptive detection. It then goes on to cover Wireless Systems Models. The robust adaptive detectors and beamformers are implemented using the well-known algorithms including LMS, RLS, IQRD-RLS, RSD, BSCMA, CG, and SD. The robust detection and beamforming are derived based on the existing detectors/beamformers including MOE, PLIC, LCCMA, LCMV, MVDR, BSCMA, and MBER. The adopted cost functions include MSE, BER, CM, MV, and SINR/SNR.

Author: Tianze Su
Publisher:
ISBN:
Category :
Languages : en
Pages :

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"In this thesis, we propose and investigate novel adaptive semi-blind channel estimation algorithms for OFDM/OQAM systems. OFDM/OQAM is regarded as a promising alternative to conventional CP-OFDM for multi-carrier modulation since it can provide better spectrum efficiency, albeit at the price of increased complexity. We first formulate a general system model of an OFDM/OQAM transceiver. Based on this model, we review a recently proposed block based semi-blind channel estimation method for OFDM/OQAM systems, known as the sign covariance matrix (SCM) method. This method mainly exploits the higher-order statistical properties of the data at the receiver side but is not well-suited for applications to time-varying channels. Subsequently, to overcome the drawbacks of this block-based technique, we propose adaptive semi-blind channel estimation algorithms for application to OFDM/OQAM. The proposed algorithms consist of an adaptive SCM technique obtained through exponential recursive averaging, as well as several constant modulus algorithms (CMA) for recursive estimation. Although all the adaptive algorithms are designed to deal with time-varying channels, they can also be used for rapid channel acquisition in the case of static or slowly-varying channels. Furthermore, we explore the coherence bandwidth of the channel and make use of this concept to improve the estimation accuracy via a frequency averaging technique that can be combined with the adaptive SCM. Simulation results validate the efficacy of the proposed adaptive estimation algorithms over both time-invariant and varying channels, showing their robustness in terms of convergence speed, tracking capability and residual estimation error in steady-state. In particular, the CMA with recursive least squares (CMA-RLS) updating proves to be the most preferable due to its excellent trade-off between convergence rate and residual error level. The CMA-RLS also offers the best performance in tracking a time-varying channel. In addition, simulation experiments demonstrate the effectiveness of combining the frequency averaging technique with the proposed adaptive SCM algorithm." --

Author: Eugene Golovins
Publisher:
ISBN:
Category :
Languages : en
Pages : 227

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Book Description

Author: Soham Sarkar
Publisher: John Wiley & Sons
ISBN: 1119571421
Category : Technology & Engineering
Languages : en
Pages : 288

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Book Description
A comprehensive review of the most recent applications of intelligent multi-modal data processing Intelligent Multi-Modal Data Processing contains a review of the most recent applications of data processing. The Editors and contributors – noted experts on the topic – offer a review of the new and challenging areas of multimedia data processing as well as state-of-the-art algorithms to solve the problems in an intelligent manner. The text provides a clear understanding of the real-life implementation of different statistical theories and explains how to implement various statistical theories. Intelligent Multi-Modal Data Processing is an authoritative guide for developing innovative research ideas for interdisciplinary research practices. Designed as a practical resource, the book contains tables to compare statistical analysis results of a novel technique to that of the state-of-the-art techniques and illustrations in the form of algorithms to establish a pre-processing and/or post-processing technique for model building. The book also contains images that show the efficiency of the algorithm on standard data set. This important book: Includes an in-depth analysis of the state-of-the-art applications of signal and data processing Contains contributions from noted experts in the field Offers information on hybrid differential evolution for optimal multilevel image thresholding Presents a fuzzy decision based multi-objective evolutionary method for video summarisation Written for students of technology and management, computer scientists and professionals in information technology, Intelligent Multi-Modal Data Processing brings together in one volume the range of multi-modal data processing.

Author: Farah Zaarour
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
The scarcity of the radio spectrum and the increasing demand on bandwidth makes it vital to optimize the spectrum use. While a maximum efficiency should be attained, a minimal interference level should be maintained. OFDM has been selected as the modulation scheme in several wireless standards. Channel estimation is a fundamental task in OFDM and it becomes even more challenging in the presence of interference. In this thesis, our aim is to propose channel estimation algorithms for OFDM systems in the presence of interference, where conventional channel estimators designed for OFDM fail. First, we consider the cognitive radio environment and propose a novel channel estimation framework for fast time-varying channels in OFDM with NBI. This is accomplished through an expectation maximization (EM) based algorithm. This formulation allows us to obtain a closed-form expression for the estimation of the noise power. In this thesis, we are particularly interested in a very recent scheme of superimposed pilots for OFDM (DNSP). DNSP assures interference-free pilots at the expense of data interference. Seen the modernity of DNSP, a suitable receiver has to be designed to cope with its design. We first propose a low-complexity interference canceler (IC) for slow time-varying channels with DNSP. The performance of the proposed IC is guaranteed when the channel estimation error is small. As another contribution, we extend the design of the approximated IC for DNSP so as to take the channel estimation errors into account. Finally, we consider robust channel estimation which can be viewed as one of the perspectives of this thesis.

Author: Sili Lu
Publisher:
ISBN:
Category : Algorithms
Languages : en
Pages : 196

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Book Description
Orthogonal frequency-division multiplexing (OFDM) has gained an increased popularity over the last few years and has been adopted as the modulation scheme of choice for beyond 3G mobile communication systems. This is mainly due to its high robustness to time dispersion effects and its low implementation complexity. DVB-H is the latest development within the set of Digital Video Broadcasting (DVB) standards that use OFDM as a modulation scheme. DVB-H is required to operate under high mobility conditions resulting in significant Inter-Carrier Interference (ICI). Under these conditions, the conventional one-tap per subcarrier channel estimation and equalization scheme is suboptimal since it does not account for ICI effects due to channel time-variation within an OFDM symbol. To mitigate ICI, we propose in this dissertation a simplified hybrid frequency/time-domain channel estimation algorithm. In addition, we design a reduced-complexity Q -tap frequency-domain equalizer (FEQ) and enhance its performance by integrating it with joint channel and data estimation and an ICI-mitigating pilot/data placement scheme. We also investigate differential OFDM detection as a low-complexity alternative for coherent detection and test its performance in the presence of Doppler for DVB-H system. Furthermore, we extend our approach to multiple-input multiple-out (MIMO) OFDM systems. We design a novel embedded space-frequency block code (SFBC)-OFDM scheme that performs well under high Doppler. We also propose a novel standard-conformable Cyclic Delay Diversity (CDD) scheme and its associated channel estimation scheme for comb-type OFDM transmissions, which achieves the Cramer-Rao lower bound on channel estimation mean square error.

Author: Giorgio A. Vitetta
Publisher: John Wiley & Sons
ISBN: 1118576608
Category : Technology & Engineering
Languages : en
Pages : 849

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Book Description
This book introduces the theoretical elements at the basis of various classes of algorithms commonly employed in the physical layer (and, in part, in MAC layer) of wireless communications systems. It focuses on single user systems, so ignoring multiple access techniques. Moreover, emphasis is put on single-input single-output (SISO) systems, although some relevant topics about multiple-input multiple-output (MIMO) systems are also illustrated. Comprehensive wireless specific guide to algorithmic techniques Provides a detailed analysis of channel equalization and channel coding for wireless applications Unique conceptual approach focusing in single user systems Covers algebraic decoding, modulation techniques, channel coding and channel equalisation

Author: 耿念
Publisher:
ISBN:
Category : Orthogonal frequency division multiplexing
Languages : en
Pages : 236

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Book Description

Author: Fulvio Gini
Publisher: Academic Press
ISBN: 0123972248
Category : Technology & Engineering
Languages : en
Pages : 1389

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Book Description
This second volume, edited and authored by world leading experts, gives a review of the principles, methods and techniques of important and emerging research topics and technologies in communications and radar engineering. With this reference source you will: - Quickly grasp a new area of research - Understand the underlying principles of a topic and its application - Ascertain how a topic relates to other areas and learn of the research issues yet to be resolved - Quick tutorial reviews of important and emerging topics of research in array and statistical signal processing - Presents core principles and shows their application - Reference content on core principles, technologies, algorithms and applications - Comprehensive references to journal articles and other literature on which to build further, more specific and detailed knowledge - Edited by leading people in the field who, through their reputation, have been able to commission experts to write on a particular topic