Turbo decoding for high-rate concatenated parity-check codes on PRML channels

A simple turbo decoding scheme is proposed for partial-response (PR) channe ls by using high-rate parity-check codes as an outer error-correction code (ECC), The use of the simple parity codes enables a simplified and high-spe ed implementation of the a posterior probability (APP) decoder. Its key fea ture is an iterative decoding step for the parallel concatenation of two pa rity-check outer codes connected via an interleaver, The parity iterative d ecoding can provide the high-rate parity-check outer codes with superior co rrection capability for random error-events, so it can help to reduce the d ecoding latency, The combination of the serial turbo decoding for a modifie d E-2 PR ((MEPR)-P-2) channel and the parity iterative decoding demonstrate d a coding gain of 4-5 dB at a bit error rate of 1.0E-5 for a coding rate o f 8/9.