Study On The Encoding & Decoding Of Turbo Codes And The Performance Of RS-Turbo Concatenated Codes

Turbo code, which was proposed by C.Berrou et al. in 1993, is a parallel concatenated convolutional codes ( PCCC ). It can approach the Shannon bound with random interleaver and iterative maximum-a-posteriori decoders. Now, Turbo codes is considered as one of the most exciting and potentially important developments in coding theory in many years. But the "error floor" is observed in several simulations with Turbo codes. It is not easy to improve the reliability of Turbo codes at BER's below 10~5. In this paper, a concatenated schemes using Turbo codes and an outer RS codes could perform better.This thesis investigates Turbo codes, the concatenated codes of RS codes and Turbo codes (RS-Turbo codes or RS-Turbo concatenated codes), RS-complex Rotary codes using RS codes and Complex Rotary Codes, and HARQ using Turbo codes and RS codes (RS-Turbo ARQ ). The main results and contents of this dissertation are as follows:1. The developments in channel coding theory are surveyed. It includes the Shannon theorem , Shannon limit, concatenated codes, soft decision decoding and Turbo codes.2. The encoding and algorithms of Turbo codes are discussed. The basic criterion of interleaver designing is proposed.3. The research for key techniques of RS-Turbo codes is processed. It includes: The performance of RS-Turbo codes is analyzed by the residual error, the converging defects of the iterative APP decoder and the concatenated structure. It is shown that not only the bit error rate and frame error rate are improved obviously by computer simulating, but also the iteration number and time complexity are lower than Turbo codes alone. Encoding schemes of RS-Turbo codes is designed, it includes interleaver, RS codes and Turbo codes. Decoding algorithm is provided. A new scheme of RS-Turbo codes is proposed.4. Based on the interleaving and concatenation of RS-Turbo codes, a new class of error-correct codes over two-dimension, RS-Complex Rotary Codes (RS-CR Codes ), is provided. The encoding structure and decoding algorithms are designed.5. A HARQ scheme is studied using RS-Turbo codes. The effect of different Turbo codes and RS codes with RS-Turbo ARQ is discussed. A HARQ of the parallel concatenated codes using Turbo codes and RS codes is proposed.6. Finally, some conclusions for this dissertation are made, and further research directions in RS-Turbo codes, RS-Complex Rotary codes and RS-Turbo ARQ are also pointed out.