An Overview of Turbo Codes and Their Applications (original) (raw)

More than ten years after their introduction, Turbo Codes are now a mature technology that has been rapidly adopted for application in many commercial transmissions systems. This paper provides an overview of the basic concepts employed in Convolutional and Block Turbo Codes, and review the major evolutions in the field with an emphasis on practical issues such as implementation complexity and high-rate circuit architectures. We address the use of these technologies in existing standards and also discuss future potential applications for this error-control coding technology.

Turbo Codes: From First Principles to Recent Standards

Elsevier eBooks, 2014

This chapter is a general introduction to the original turbo codes discovered in the early 1990s and also known as convolutional turbo codes or parallel concatenated convolutional codes. It presents the main concepts of coding theory introduced with the invention of turbo codes, put in an historical perspective. The overall structures of the encoder and decoder are analyzed and some fundamental guidelines for the design of turbo codes with good performance are provided. Then, the basics of turbo decoding are introduced and the main component decoding algorithms are briefly described. Finally, the very first proof-of-concept implementations are described and the pioneer telecommunication applications and current transmission standards using turbo codes are reviewed.

Turbo Codes: Promises and Challenges

Channel coding is a powerful technique to get reliable communication over noisy channels. The performance of the coding system is bounded by Shannon limit. Lately, the proposal of parallel-concatenated convolutional code (PCCC), called turbo codes, has increased the interest in the coding area since these codes give most of the gain promised by the channel-coding theorem. Because turbo codes did not actually results from applying a pre existing theory, most of their outstanding features remain to be explained. The objective of this paper is to introduce turbo codes and the key elements to their superiority. Open problems and unresolved issues will be highlighted.

Recent Advances in Turbo Code Design and Theory

Proceedings of the IEEE, 2000

The interleaver, which combines the outputs of turbo decoders, is essential in determining the performance of turbo codes and is the main source of decoder computation and implementation complexity. ABSTRACT | The discovery of turbo codes and the subsequent rediscovery of low-density parity-check (LDPC) codes represent major milestones in the field of channel coding. Recent advances in the design and theory of turbo codes and their relationship to LDPC codes are discussed. Several new interleaver designs for turbo codes are presented which illustrate the important role that the interleaver plays in these codes. The relationship between turbo codes and LDPC codes is explored via an explicit formulation of the parity-check matrix of a turbo code, and simulation results are given for sum product decoding of a turbo code.

On The Performance of Turbo Codes With Convolutional Interleavers

2005 Asia-Pacific Conference on Communications, 2005

In this paper, some issues governing the block-wise performance of convolutional interleavers used in turbo codes are presented. Two different constructions of convolutional interleaver differing by the position of stuff bits in the interleaved data block are considered here. The performance assessment is based on the contribution of each weight to the overall code performance. For the given turbo code and each utilized interleaver, weight contribution is computed to finalize the code behavior in different signal to noise ratios. Simulations have been performed to verify the conducted analysis.

System Level Design Guidelines for the Use of Turbo Product Codes

2001

Turbo Product Codes (TPCs) are receiving industry acceptance as an excellent forward error correction (FEC) solution. TPCs give performance that is within 1 dB of the theoretical maximum performance achievable for additive white gaussian noise (AWGN) channels [1, 2]. TPCs outperform FEC schemes currently in hardware such as Reed Solomon and Viterbi, by over 2 dB [1]. Their performance on Rayleigh fading channels is within 2 dB of capacity limits, and offers even more significant gains over traditional coding technologies [7]. Also for systems seeking high bandwidth efficiency through the use of higher order modulation or space time codes, TPC solutions offer unbeatable performance [3,4,8]. TPCs also offer equivalent and often superior performance to Turbo Convolutional Codes and the generality of TPCs in this paper will exemplify their use in future systems.

Convolutional interleaver for unequal error protection of turbo codes

2000

This paper describes construction of a convolutional interleaver as a block interleaver and discusses its application to turbo codes with equal and unequal error protection techniques. Based on simulations, different convolutional interleaver structures suitable for turbo codes with unequal error protection capability are suggested. Finally, based on conducted simulations the best method is selected.

Application of convolutional interleavers in turbo codes with unequal error protection

This paper deals with an application of convolutional interleavers in unequal error protection (UEP) turbo codes. The constructed convolutional interleavers act as block interleavers by inserting a number of stuff bits into the interleaver memories at the end of each data block. Based on the properties of this interleaver, three different models of UEP turbo codes are suggested. Simulation results confirm that utilizing UEP can provide better protection for important parts of each data block, while significantly decreasing the number of stuff bits.

Modified convolutional interleavers and their performance in turbo codes

SympoTIC '04. Joint 1st Workshop on Mobile Future & Symposium on Trends In Communications (IEEE Cat. No.04EX877), 2004

In previous work,we have presented application of a model of the convolutional interleaver in turbo codes acting as a block interleaver through inserting a number of stuff bits equal to the number of interleaver memories at the end of each data 6lock.h order to get better turbo codes performance, the interleaver with larger period, which increases the number of stuff bits and educes effective channel bandwidth usage, has been suggested. In this paper, we introduce a modification to this interleaver improving turbo codes performance without increasing the interleaver period. This is carried out by increasing distance of adjacent bits that are positioned in original input bit stream in the interleaving procedure. Application of the modified interleaver in different turbo codes'structures have been verified and results have been compared with those for the previously suggested interleaver.

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