Reduced Complexity Decoding and Relative Performance of Turbo Codes PDF Download

Author: Chi Wa Leong
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Author:
Publisher:
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Category :
Languages : en
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The thesis has two main topics, both related to turbo codes. The first one deals with the design of reduced complexity decoding of turbo codes. In particular, two new decoders are designed using ideas from the M-algorithm: one to decode the constituent code and the other the entire turbo code. Both decoders are found to be suitable only for short turbo codes with information block size less than 300 bits. For these turbo codes the two decoders have a lower complexity with a small degradation in error performance when compared to the original decoder used to decode the turbo codes. Therefore they are recommended in applications where short turbo codes are used and a small processing delay is required. The second topic of the thesis is whether the turbo code is superior to any other code. A partial answer is found by comparing short BCH codes to turbo codes with similar parameters. It is found that the BCH codes are more attractive than the turbo codes in both decoding complexity and error performance. This implies that traditional block codes are better than turbo codes with similar parameters.

Author: Aliazam Abbasfar
Publisher: Springer Science & Business Media
ISBN: 1402063911
Category : Technology & Engineering
Languages : en
Pages : 94

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This book introduces turbo error correcting concept in a simple language, including a general theory and the algorithms for decoding turbo-like code. It presents a unified framework for the design and analysis of turbo codes and LDPC codes and their decoding algorithms. A major focus is on high speed turbo decoding, which targets applications with data rates of several hundred million bits per second (Mbps).

Author: Nagi Issam Mounsef
Publisher:
ISBN:
Category :
Languages : en
Pages : 186

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Despite the impressive performance of turbo codes, one main concern in the imple mentation of such systems is their complexity. For some applications, like softw are radios, the full complexity iterative decoder is prohibitively complex. It h as been an interesting and important open question to find a larger class of dec oding algorithms for turbo codes that allow one to trade off performance with co mplexity, in a larger range. This thesis discusses some general ideas to provide a conceptual understanding t o address this problem. We then consider an alternative concept of turbo decodin g to reduce the computational complexity. A new algorithm to reduce the computat ional complexity of iterative decoding is presented. The algorithm reduces the c omplexity by removing certain branches from the corresponding trellis diagram. A threshold on reliability values is used as the elimination criterion. This deco ding is much easier to process and the loss of bit error rate (BER) performance is quite small or even negligible in comparison to conventional turbo decoding. First, the fundamental concept of the SOVA turbo decoding algorithm is explored.

Author: Shirin Esfandiari
Publisher:
ISBN:
Category : Algorithms
Languages : en
Pages : 0

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For effective communication to take place between a source and a destination the emphasis lies on the reliable transport of information. Given the constraints of the transport medium, there is much emphasis on the research techniques that allow a good trade off between complexity and performance. Despite the superior performance of turbo product codes, one main concern is the implementation complexity of such systems. With this in mind, in this thesis we present, a reduced complexity decoding algorithm for turbo product codes. This scheme is based on the reduction of the complexity of a soft input soft output trellis based iterative decoder by means of simplifying the trellis structure. We present the details involved in pruning certain branches based on the values of the received channel information and the extrinsic information associated to each branch. We introduce the concept of branch pruning by means of using a threshold, and investigate the methods for compensating for the performance degradation (in terms of bit error rate) in a system where a structural complexity simplification such as trellis pruning is in effect.

Author: Keattisak Sripimanwat
Publisher: Springer Science & Business Media
ISBN: 140203685X
Category : Technology & Engineering
Languages : en
Pages : 393

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Turbo Code Applications: a journey from a paper to realization presents c- temporary applications of turbo codes in thirteen technical chapters. Each chapter focuses on a particular communication technology utilizing turbo codes, and they are written by experts who have been working in related th areas from around the world. This book is published to celebrate the 10 year anniversary of turbo codes invention by Claude Berrou Alain Glavieux and Punya Thitimajshima (1993-2003). As known for more than a decade, turbo code is the astonishing error control coding scheme which its perf- mance closes to the Shannon’s limit. It has been honored consequently as one of the seventeen great innovations during the ?rst ?fty years of information theory foundation. With the amazing performance compared to that of other existing codes, turbo codes have been adopted into many communication s- tems and incorporated with various modern industrial standards. Numerous research works have been reported from universities and advance companies worldwide. Evidently, it has successfully revolutionized the digital commu- cations. Turbo code and its successors have been applied in most communications startingfromthegroundorterrestrialsystemsofdatastorage,ADSLmodem, and ?ber optic communications. Subsequently, it moves up to the air channel applications by employing to wireless communication systems, and then ?ies up to the space by using in digital video broadcasting and satellite com- nications. Undoubtedly, with the excellent error correction potential, it has been selected to support data transmission in space exploring system as well.

Author: Yassir Nawaz
Publisher:
ISBN:
Category : Error-correcting codes (Information theory)
Languages : en
Pages : 192

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Author: Alexandre Giulietti
Publisher: Springer Science & Business Media
ISBN: 1461504775
Category : Technology & Engineering
Languages : en
Pages : 158

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PREFACE The increasing demand on high data rate and quality of service in wireless communication has to cope with limited bandwidth and energy resources. More than 50 years ago, Shannon has paved the way to optimal usage of bandwidth and energy resources by bounding the spectral efficiency vs. signal to noise ratio trade-off. However, as any information theorist, Shannon told us what is the best we can do but not how to do it [1]. In this view, turbo codes are like a dream come true: they allow approaching the theoretical Shannon capacity limit very closely. However, for the designer who wants to implement these codes, at first sight they appear to be a nightmare. We came a huge step closer in striving the theoretical limit, but see the historical axiom repeated on a different scale: we know we can achieve excellent performance with turbo codes, but not how to realize this in real devices.

Author: Chen Jinghu
Publisher:
ISBN:
Category : Decoders (Electronics)
Languages : en
Pages : 234

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Author: Lajos L. Hanzo
Publisher: Wiley-IEEE Press
ISBN: 9780470847268
Category : Technology & Engineering
Languages : en
Pages : 766

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Turbo coding has opened an exciting new chapter in the design of iterative detection assisted communication systems. Similar dramatic advances have been achieved with the advent of space time coding, when communicating over dispersive fading wireless channels. By assuming no prior knowledge in the field of channel coding, the authors provide a self-contained reference on these stimulating hot topics, concluding at an advanced level. This essential volume is divided into five key parts: 1. Convolutional and Block Coding Introduces the family of convolutional codes, hard and soft-decision Viterbi algorithms and the most prominent classes of block codes, namely Reed-Solomon (RS) and Bose-Chaudhuri-Hocquenghem (BCH) codes, as well as their algebraic and trellis-decoding. 2. Turbo Convolutional and Turbo Block Coding Introduces turbo convolutional codes and details the Maximum A-Posteriori (MAP), Log-MAP and Max-Log-MAP as well as the Soft Output Viterbi Algorithm (SOVA). Investigates the effects of the various turbo codec parameters. Studies the super-trellis structure of turbo codes and characterises turbo BCH codes. Portrays Redundant Residue Number System (RRNS) based codes and their turbo decoding. 3. Coded Modulation: TCM, TTCM, BICM, BICM-ID Studies Trellis Coded Modulation (TCM), Turbo Trellis Coded Modulation (TTCM), Bit-Interleaved Coded Modulation (BICM), Iterative BICM (BICM-ID) and compares them under various channel conditions. 4. Space-Time Block and Space-Time Trellis Coding Introduces space-time codes and studies their performance using numerous channel codecs providing guidelines for system designers. Studies Multiple-Input Multiple-Output (MIMO) based schemes and the concept of near-instantaneously Adaptive Quadrature Amplitude Modulation (AQAM) combined with near-instantaneously adaptive turbo channel coding. 5. Turbo Equalisation Covers the principle in detail, provides theoretical performance bounds for turbo equalisers and includes a study of various turbo equaliser arrangements. Also addresses the problem of reduced implementation complexity and covers turbo equalised space-time trellis codes. If you are looking for a comprehensive treatment covering both classic channel coding techniques and recent advances in this field, then this is the book for you. Researchers, practising engineers and advanced students will all find it both informative and stimulating.