Synchronization Techniques For Digital Communication Systems

Synchronization is a critical function in digital communications; its failures may have catastrophic effects on the transmission system performance. Furthermore, synchronization circuits comprehend such a large part of the receiver hardware that their implementation has a substantial impact on the overall costs. For these reasons design engineers are particularly concerned with the development of new and more efficient synchronization structures. Unfortunately, the advent of digital VLSI technology has radically affected modem design rules, to a point that most analog techniques employed so far have become totally obsolete. Although digital synchronization methods are well established by now in the literature, they only appear in the form of technical papers, often concentrating on specific performance or implementation issues. As a consequence they are hardly useful to give a unified view of an otherwise seemingly heterogeneous field. It is widely recognized that a fundamental understanding of digital synchronization can only be reached by providing the designer with a solid theoretical framework, or else he will not know where to adjust his methods when he attempts to apply them to new situations. The task of the present book is just to develop such a framework.

Do you need to know how to develop more efficient digital communication systems? Based on the author's experience of over thirty years in industrial design, this practical guide provides detailed coverage of synchronization subsystems and their relationship with other system components. Readers will gain a comprehensive understanding of the techniques needed for the design, performance analysis and implementation of synchronization functions for a range of different modern communication technologies. Specific topics covered include frequency-looked loops in wireless receivers, optimal OFDM timing phase determination and implementation, and interpolation filter design and analysis in digital resamplers. Numerous implementation examples help readers to develop the necessary practical skills, and slides summarizing key concepts accompany the book online. This is an invaluable guide and essential reference for both practicing engineers and graduate students working in digital communications.

Since the early 1990s, when synchronization of chaotic communication systems became a popular research subject, a vast number of scientific papers have been published. However, most of today’s books on chaotic communication systems deal exclusively with the systems where perfect synchronization is assumed, an assumption which separates theoretical from practical, real world, systems. This book is the first of its kind dealing exclusively with the synchronization techniques for chaotic communication systems. It describes a number of novel robust synchronization techniques, which there is a lack of, for single and multi-user chaotic communication systems published and highly cited in world’s leading journals in the area. In particular, it presents a solution to the problem of robust chaotic synchronization by presenting the first fully synchronized, highly secure, chaos based DS-CDMA system. The book fills a gap in the existing literature where a number of books exist that deal with chaos and chaotic communications but not with synchronization of chaotic communication systems. It also acts as a bridge between communication system theory and chaotic synchronization by carefully explaining the two concepts and demonstrating how they link into chaotic communication systems. The book also presents a detailed literature review on the topic of synchronization of chaotic communication systems. Furthermore, it presents the literature review on the general topic of chaotic synchronization and how those ideas led to the application of chaotic signals to secure chaotic communication systems. It therefore, in addition to presenting the state of the art systems, also presents a detailed history of chaotic communication systems. In summary, the book stands out in the field of synchronization techniques for chaotic communication systems.

"Timing synchronization plays an important role in recovering the original transmitted signal in telecommunication systems. In order to have a communication system that operates at the correct time and in the correct order, it is necessary to synchronize to the transmitter’s symbol timing. Synchronization can be accomplished when the receiver clock tracks the periodic timing information in a transmitted signal to reproduce the original signal. In this thesis work, we report the design, implementation and evaluation of a timing synchronization algorithm based on the technique first proposed by Gardner [1], applied to wireless communication using the Alamouti spacetime code [2] under QPSK modulation with halfsine pulses. To achieve this, a mathematical model is introduced which includes software design of communication algorithms. In this modeling, we simulate the Gardner algorithm in MATLAB. Then, five techniques are introduced to improve the performance of the loop filter in the digital receiver, and they are successfully implemented and evaluated in Matlab. These five techniques prove that there is an improvement in digital receiver performance in terms of the convergence speed and the communication system complexity. On the other hand, the optimum decoding of the Alamouti spacetime code, as initially proposed, makes the nontrivial assumption that the communication system is perfectly synchronized. Realistic wireless environments contain additive white Gaussian noise (AWGN), multipath fading, and it is not perfectly synchronized. In this thesis, the Alamouti spacetime code technique is written for QPSK modulation scheme to work in realistic environment that involves a timing synchronization technique. We compare the bit error rate (BER) of the Alamouti decoder when synchronized using the proposed algorithms with the ideal results found in the literature, and we find them to be similar, proving that the synchronization algorithm is in fact achieving optimum synchronization. This thesis presents synchronization algorithms that are necessary for a complete working wireless Alamouti technique. Also, this thesis improves the communication system performance in terms of the convergence speed with reducing the computational complexity of the communication system design."--Abstract.

Synchronization is a critical function in digital communications; its failures may have catastrophic effects on the transmission system performance. Furthermore, synchronization circuits comprehend such a large part of the receiver hardware that their implementation has a substantial impact on the overall costs. For these reasons design engineers are particularly concerned with the development of new and more efficient synchronization structures. Unfortunately, the advent of digital VLSI technology has radically affected modem design rules, to a point that most analog techniques employed so far have become totally obsolete. Although digital synchronization methods are well established by now in the literature, they only appear in the form of technical papers, often concentrating on specific performance or implementation issues. As a consequence they are hardly useful to give a unified view of an otherwise seemingly heterogeneous field. It is widely recognized that a fundamental understanding of digital synchronization can only be reached by providing the designer with a solid theoretical framework, or else he will not know where to adjust his methods when he attempts to apply them to new situations. The task of the present book is just to develop such a framework.

Today’s networks of processors on and off chip, operating with independent clocks, need effective synchronization of the data passing between them for reliability. When two or more processors request access to a common resource, such as a memory, an arbiter has to decide which request to deal with first. Current developments in integrated circuit processing are leading to an increase in the numbers of independent digital processing elements in a single system. With this comes faster communications, more networks on chip, and the demand for more reliable, more complex, and higher performance synchronizers and arbiters. Written by one of the foremost researchers in this area of digital design, this authoritative text provides in-depth theory and practical design solutions for the reliable working of synchronization and arbitration hardware in digital systems. The book provides methods for making real reliability measurements both on and off chip, evaluating some of the common difficulties and detailing circuit solutions at both circuit and system levels. Synchronization and Arbitration in Digital Systems also presents: mathematical models used to estimate mean time between failures in digital systems; a summary of serial and parallel communication techniques for on-chip data transmission; explanations on how to design a wrapper for a locally synchronous cell, highlighting the issues associated with stoppable clocks; an examination of various types of priority arbiters, using signal transition graphs to show the specification of different designs (from the simplest to more complex multi-way arbiters) including ways of solving problems encountered in a wide range of applications; essential information on systems composed of independently timed regions, including a discussion on the problem of choice and the factors affecting the time taken to make choices in electronics. With its logical approach to design methodology, this will prove an invaluable guide for electronic and computer engineers and researchers working on the design of digital electronic hardware. Postgraduates and senior undergraduate students studying digital systems design as part of their electronic engineering course will struggle to find a resource that better details the information given inside this book

Introduction to Digital Communications explores the basic principles in the analysis and design of digital communication systems, including design objectives, constraints and trade-offs. After portraying the big picture and laying the background material, this book lucidly progresses to a comprehensive and detailed discussion of all critical elements and key functions in digital communications. The first undergraduate-level textbook exclusively on digital communications, with a complete coverage of source and channel coding, modulation, and synchronization. Discusses major aspects of communication networks and multiuser communications Provides insightful descriptions and intuitive explanations of all complex concepts Focuses on practical applications and illustrative examples. A companion Web site includes solutions to end-of-chapter problems and computer exercises, lecture slides, and figures and tables from the text