Design and Simulation of Turbo Codec for Error Reduction Using MSOVA Algorithm

Turbo codes are well known to be one of the error correction techniques which achieve closer results to the Shannon limit in modern communication systems. Turbo codes play an important role in making wireless communications systems such as WiMAX and 4G LTE more efficient and reliable. However, the peculiar performance of the code profoundly depends on the particular decoding algorithm used at the receiver. In this era, the selection of the decoding algorithm involves a trade-off between the BER (Bit error rate) performance introduced by the code and the complexity of the decoding process.In this paper a modification over SOVA (soft-output Viterbi algorithm) has been proposed which prune some path by using thresholding. It performs as good as the LOG-MAP algorithm with a reduced complexity as compared to the conventional SOVA algorithm. As the complexity of SOVA algorithm is already less as compared to LOG-MAP. The MSOVA results in a much reduced complexity in comparison to LOG-MAP. The simulation results for turbo codec using MSOVA algorithm is obtained over MATLAB r2013a show an approximately 0.35db gain over LOG-MAP at BER of 0.069. The BER performance graph for different iterations and different coding length is also included in this paper.