Decoding Algorithms And Implemental Techniques Of Turbo Codes

With introduction of the principle of Turbo codes and analysis of their performances in theory, decoding algorithms and implemental techniques are mainly studied. Aim to the faults of conventional soft-output Viterbi algorithm, such as bad performance, high sequence delay and storage requirement, a new algorithm called slide-window modified soft-output Viterbi algorithm (SW-MSOVA) is presented. The performance is improved by reducing the inherent strong correlation between the intrinsic information (input to the SOVA) and extrinsic information (output of the SOVA). Moreover, the sequence delay and storage requirement are reduced by a slide-window scheme. Base on choice of the parameters of designing Turbo codes and quantification of different signals, the implement of a Turbo decoder with SW-MSOVA is introduced. The throughput of the decoder is increased through two-state ACSs and Modulo normalization technique for state metrics.