Enhancement of Hybrid Concatenated Codes Using A Modified Log-MAP Algorithm

To improve the performance of hybrid concatenated convolutional codes (HCCC); a modified Log-MAP algorithm and an enhanced HCCC are introduced and demonstrated to be efficient and practical by simulation results. The new coding scheme achieves about 1.0 dB additional coding gain, compared to the general turbo coding scheme at a BER = 10-6, with a frame length of 8192-bit. The system complexity and decoding latency of the new scheme is lower than the HCCC proposed by Divsalar and Pollara (1997) within acceptable performance degradation. Since the bit error-rate of the proposed HCCC can be dramatically reduced by slightly increasing signal-to-noise ratio, the new hybrid concatenated coding scheme is very suitable for those communication environments in which high reliability is important.