Parallel implementation of turbo-decoders for satellite and wireless communication systems

In a turbo coding scheme, different codewords require different numbers of iterations for being correctly decoded. If a fixed number of iterations is allocated to each frame, it is possible that certain frames remain erroneous while decoder is idle part of the time for other frames. In this paper idea of sharing the processing power among different frames, possibly, belonging to different channels, is presented. This time-sharing approach can increase the processing throughput and/or the performance of the turbo decoding scheme. We present two schemes and give their performance for the 3GPP code. We also investigate the implementation of these schemes using a digital signal processor (DSP) chip. At the end, we present an efficient implementation algorithm by combining those two multi-channel processing schemes.