Analysis and Evaluation of Turbo Coding and Decoding Algorithms Based on Low SNR

Due to the excellent performance of error correcting, turbo codes have been selected as the candidate channel coding schemes for CDMA2000 and WCDMA. This paper studies the basic principle of turbo codes and their coding and decoding algorithms and computer simulation. The design of the Turbo encoding, and decoding systems adopts the pseudo-random interleaver which breaks the relation that the low weight input sequence produces the low weight code sequence and improves the performance of the Turbo encoding and decoding systems. Simulation results and analysis show that some factors, such as the number of the times of decoding iteration, RSC codes, the length of the interleaver, and the interleaver map, will influence the performance of Turbo encoding and decoding systems.