Bahram Honary – författare

The unprecedented growth in the range of multimedia services offered these days by modern telecommunication systems has been made possible only because of the advancements in signal processing technologies and algorithms. In the area of telecommunications, application of signal processing allows for new generations of systems to achieve performance close to theoretical limits, while in the area of multimedia, signal processing the underlying technology making possible realization of such applications that not so long ago were considered just a science fiction or were not even dreamed about. We all learnt to adopt those achievements very quickly, but often the research enabling their introduction takes many years and a lot of efforts. This book presents a group of invited contributions, some of which have been based on the papers presented at the International Symposium on DSP for Communication Systems held in Coolangatta on the Gold Coast, Australia, in December 2003. Part 1 of the book deals with applications of signal processing to transform what we hear or see to the form that is most suitable for transmission or storage for a future retrieval. The first three chapters in this part are devoted to processing of speech and other audio signals. The next two chapters consider image coding and compression, while the last chapter of this part describes classification of video sequences in the MPEG domain.

It is a great pleasure to be asked to write the Preface for this book on trellis decoding of error correcting block codes. The subject is extremely significant both theoretically and practically, and is very timely because of recent devel­ opments in the microelectronic implementation and range of application of error-control coding systems based on block codes. The authors have been notably active in signal processing and coding research and development for several years, and therefore very well placed to contribute to the state of the art on the subject of trellis decoding. In particular, the book represents a unique approach to many practical aspects of the topic. As the authors point out, there are two main classes of error control codes: block codes and convolutinal codes. Block codes came first historically and have a well-developed mathematical structure. Convolutional codes come later, and have developed heuristically, though a more formal treatment has emerged via recent developments in the theory of symbolic dynamics. Max­ imum likelihood (ML) decoding of powerful codes in both these classes is computationally complex in the general case; that is, ML decoding fails into the class of NP-hard computational problems. This arieses because the de­ coding complexity is an exponential function of key parameters of the code.

Examining the plans for the future and the progress that has already been made in the field of DSP and its applications to communication systems, this text pursues the progression from communication and information theory through to the implementation, evaluation and performance enhancing of practical communication systems using DSP technology. It looks at various types of coding and modulation techniques, describing different applications of Turbo-Codes, BCH codes and general block codes, pulse modulations, and combined modulation and coding in order to improve the overall system performance. The book examines DSP applications in measurements performed for channel characterization, pursues the use of DSP for design of effective channel simulators, and discusses equalization and detection of various signal formats for different channels. A number of system design issues are presented where digital signal processing is involved, reporting on the successful implementation of the system components using DSP technology, and including the problems involved with implementation of some DSP algorithms.The book serves as a resource for professionals and researchers who deal with digital signal processing for communication systems, and may serve as a text for advanced courses on the subject.

Advancements in communication systems performance have been possible because of digital signal processing applied in all areas of communication systems development and implementation. This volume consists of 20 contributions from researchers and experts. The first group of chapters deals with the audio and video processing for communications applications, including topics ranging from multimedia content delivery over the Internet, through the speech processing and recognition to recognition of non-speech sounds that can be attributed to the surrounding environment. Aspects of Orthogononal Frequency Division Multiplexing (OFDM) technology covered include novel forms of modulation and coding, methods of reducing in-band and out-of-band spurious signal generation, and means of reducing the peak-to-average power ratio of an OFDM waveform. In these contributions, a key objective is to return the inherent implementational simplicity of the OFDM technique while enhancing its performance relative to single carrier systems. Digital signal processing for second and third generation systems is also represented.The topics cover both theoretical issues like spreading sequence design and implementation issues of 3G user equipment modem, and MMSE receivers for CDMA systems. A comparison of complexity of channel estimation, equalization and decoding for GSM receivers is discussed and there are sections on applications of error control coding, information theory, and digital signal processing for communication systems like modulation, software-defined radio, and channel estimation.

Digital Signal Processing for Communication Systems examines the plans for the future and the progress that has already been made, in the field of DSP and its applications to communication systems. The book pursues the progression from communication and information theory through to the implementation, evaluation and performance enhancing of practical communication systems using DSP technology. Digital Signal Processing for Communication Systems looks at various types of coding and modulation techniques, describing different applications of Turbo-Codes, BCH codes and general block codes, pulse modulations, and combined modulation and coding in order to improve the overall system performance. The book examines DSP applications in measurements performed for channel characterisation, pursues the use of DSP for design of effective channel simulators, and discusses equalization and detection of various signal formats for different channels. A number of system design issues are presented where digital signal processing is involved, reporting on the successful implementation of the system components using DSP technology, and including the problems involved with implementation of some DSP algorithms. Digital Signal Processing for Communication Systems serves as an excellent resource for professionals and researchers who deal with digital signal processing for communication systems, and may serve as a text for advanced courses on the subject.

It is a great pleasure to be asked to write the Preface for this book on trellis decoding of error correcting block codes. The subject is extremely significant both theoretically and practically, and is very timely because of recent devel­ opments in the microelectronic implementation and range of application of error-control coding systems based on block codes. The authors have been notably active in signal processing and coding research and development for several years, and therefore very well placed to contribute to the state of the art on the subject of trellis decoding. In particular, the book represents a unique approach to many practical aspects of the topic. As the authors point out, there are two main classes of error control codes: block codes and convolutinal codes. Block codes came first historically and have a well-developed mathematical structure. Convolutional codes come later, and have developed heuristically, though a more formal treatment has emerged via recent developments in the theory of symbolic dynamics. Max­ imum likelihood (ML) decoding of powerful codes in both these classes is computationally complex in the general case; that is, ML decoding fails into the class of NP-hard computational problems. This arieses because the de­ coding complexity is an exponential function of key parameters of the code.

Advanced Signal Processing for Communication Systems consists of 20 contributions from researchers and experts.The first group of chapters deals with the audio and video processing for communications applications, including topics ranging from multimedia content delivery over the Internet, through the speech processing and recognition to recognition of non-speech sounds that can be attributed to the surrounding environment.The book also includes sections on applications of error control coding, information theory, and digital signal processing for communication systems like modulation, software-defined radio, and channel estimation.Advanced Signal Processing for Communication Systems is written for researchers working on communication systems and signal processing, as well as telecommunications industry professionals.

The unprecedented growth in the range of multimedia services offered these days by modern telecommunication systems has been made possible only because of the advancements in signal processing technologies and algorithms. In the area of telecommunications, application of signal processing allows for new generations of systems to achieve performance close to theoretical limits, while in the area of multimedia, signal processing the underlying technology making possible realization of such applications that not so long ago were considered just a science fiction or were not even dreamed about. We all learnt to adopt those achievements very quickly, but often the research enabling their introduction takes many years and a lot of efforts. This book presents a group of invited contributions, some of which have been based on the papers presented at the International Symposium on DSP for Communication Systems held in Coolangatta on the Gold Coast, Australia, in December 2003. Part 1 of the book deals with applications of signal processing to transform what we hear or see to the form that is most suitable for transmission or storage for a future retrieval. The first three chapters in this part are devoted to processing of speech and other audio signals. The next two chapters consider image coding and compression, while the last chapter of this part describes classification of video sequences in the MPEG domain.