Turbo-like Codes (eBook)

Design for High Speed Decoding

Aliazam Abbasfar (Autor)

eBook Download: PDF

2007 | 2007
XVIII, 84 Seiten
Springer Netherlands (Verlag)
978-1-4020-6391-6 (ISBN)

Infos

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).

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The common property among turbo-like code is that they consist of very simple constituent codes that are connected to each other with random or pseudorandom interleavers. The crucial novelty in these codes is the iterative decoding. This means that the constituent codes are decoded separately, which is ef?cient and practically feasible since they are very simple codes. Then, they pass new information to each other in a course of a few iterations. It has been shown that iterative decoding is a generalization of the well-known probability or belief propagation algorithm. The belief propagation algorithm that has been essential for development of new ideas throughout this work is described in the context of coding. The basic theorems for this algorithm are explained and proven in the following paragraphs. Thisis then followed by a description of the computational algorithm. The probability propagation algorithm is proven in c- junctionwithatree-structuredgraph-graphswithoutanycycle.Infact,thegraphical representation of any problem solved by this algorithm is the centerpiece of the algorithm. The generalization of the algorithm for graphs with cycles is presented later on. Representation of codes on graph is the next step towards characterization of the iterative decoding as an example of the probability propagation algorithm. The graph representations are presented for a few codes that are commonly used in turbo-like codes.

Inhalt

List of Figures. List of Tables. Acknowledgments. Abstract. 1 Introduction. 1.1 Outline. 2 Turbo concept. 2.1 Turbo codes and turbo-like codes. 2.2 Iterative decoding. 2.3 Probability propagation algorithms. 2.4 Message passing algorithm. 2.5 Graphs with cycles. 2.6 Codes on graph. 3 High speed turbo decoders. 3.1 Introduction. 3.2 BCJR algorithm. 3.3 Turbo decoding. 3.4 Pipelined turbo decoder. 3.5 Parallel turbo decoder. 3.6 Speed gain and efficiency. 3.7 Interleaver Design. 3.8 Hardware complexity. 3.9 Conclusion. 4 Very simple turbo-like codes. 4.1 Introduction. 4.2 RA codes. 4.3 RA codes with puncturing. 4.4 ARA codes. 4.5 Other precoders. 4.6 Hardware complexity. 4.7 Conclusion. 5 High speed turbo-like decoders. 5.1 Introduction. 5.2 Parallel ARA decoder. 5.3 Speed gain and efficiency. 5.4 Interleaver design. 5.5 Projected graph. 5.6 General hardware architecture. 5.7 Conclusion. References. Index.

Produkt-Details

• Erscheint lt. Verlag: 9.9.2007
• Zusatzinfo: XVIII, 84 p.
• Verlagsort: Dordrecht
• Sprache: englisch
• Themenwelt: Informatik ► Theorie / Studium ► Kryptologie
• Themenwelt: Naturwissenschaften
• Themenwelt: Technik ► Elektrotechnik / Energietechnik
• Themenwelt: Technik ► Nachrichtentechnik
• Schlagworte: algorithms • Channel coding/Error correcting codes • Code • Complexity • High speed turbo decoding • LDPC Codes • RA/ARA codes • turbo codes
• ISBN-10: 1-4020-6391-1 / 1402063911
• ISBN-13: 978-1-4020-6391-6 / 9781402063916