Delay-Limited Rate-Compatible Protograph LDPC Codes

摘要

This paper produces a family of ratecompatible protographbased lowdensity paritycheck (PLDPC) codes that have superior performance under strict constraints of short block length and low decoding iterations. The design of such practical codes is a challenging task since the constraints imposed by structured designs (PLDPC), ratecompatibility, small block length, as well as a small number of decoding iterations, are hard to meet simultaneously. As the block length and the number of decoding iterations decrease, the typical LDPC design based only on the coding threshold is no longer effective due to imperfection in the modeling of LDPC decoders in the short block length regime. We propose a code design method that takes the code simulations and the number of the decoding iterations as inputs to optimize the new codes. Analytical and simulation results confirm that the new codes produced by the proposed approach outperform the stateoftheart codes in a wide range of code rates. None of the newly optimized codes has the errorfloor behavior even below the frame error rate of 10sup5/supor bit error rate of 10sup6/sup.