In this letter, a low complexity decoding algorithm for binary linear block codes is applied to low-density paritycheck (LDPC) codes and improvements are described, namely an extension to soft-decision decoding and a loop detection mechanism. For soft decoding, only one real-valued addition per code symbol is needed, while the remaining operations are only binary as in the hard decision case. The decoding performance is considerably increased by the loop detection. Simulation results are used to compare the performance with other known decoding strategies for LDPC codes, with the result that the presented algorithms offer excellent performances at smaller complexity.

In this paper, a low complexity algorithm for binary linear block codes is applied to low-density parity-check (LDPC) codes and improvements are described, namely an extension to soft-decision decoding and a loop detection mechanism. For soft decoding, only one real-valued addition per code symbol is needed, while the remaining operations are only binary as in the hard decision case. The decoding performance is considerably increased by the loop detection. Simulation results are used to compare the performance with other known decoding strategies for LDPC codes, with the result that the presented algorithms offer excellent performance at smaller complexity.

This work investigates the performance of a class of concatenated error correcting block codes, called generalized error-locating codes, over partial response channels as they are found in digital magnetic storage systems. Generalized error-locating codes are suited for high-rate high-speed applications due to the low-complexity hard input decoding algorithm. The code and the decoding algorithm is constructed according to the error structure of the channel to spend the redundancy in an advantageous way. Simulation results for the (precoded) partial response channel 1-D/sup 2/ (PR4) compare results for different sector lengths. It is also explained how a modulation constraint can be included in the system. The generalized error-locating codes show an impressive gain over the classically used Reed-Solomon outer codes with comparable decoding complexity.