Turbo Equalization as a Postprocessor for Partial-Response Channels

Abstract

Post-Viterbi processors are used for detection of partial-response channels coded with weak parity codes, whereas turbo equalization is usually used for detection and decoding of strong low-density parity check (LDPC) codes. This digest discusses the use of turbo equalization for joint detection and decoding of parity codes that would be used in postprocessing systems. The proposed system has complexity significantly lower than conventional LDPC-turbo equalization systems, and has excellent performance vis-a-vis postprocessing systems. The flexibility of the proposed system is demonstrated by considering an unequal error protection (UEP) code which preferentially places Viterbi algorithm error events within Reed-Solomon symbol boundaries to decrease the sector error rate.