Performance Comparisons of Improved Regular Repeat Accumulate (RA) and Irregular Repeat Accumulate (IRA) Turbo Decoding


In this paper, different techniques are used to improve the turbo decoding of regular repeat accumulate (RA) and irregular repeat accumulate (IRA) codes. The adaptive scaling of a-posteriori information produced by Soft-output Viterbi decoder (SOVA) is proposed. The encoded pilots are another scheme that applied for short length RA codes. This work also suggests a simple and a fast method to generate a random interleaver having a free 4 cycle Tanner graph. Progressive edge growth algorithm (PEG) is also studied and simulated to create the Tanner graphs which have a great girth.