Adaptive Decoding of LDPC Codes with Binary Messages

Land, Ingmar; Lechner, Gottfried; Rasmussen, Lars K.

Adaptive Decoding of LDPC Codes with Binary Messages

Authors

Land, Ingmar

Lechner, Gottfried

Rasmussen, Lars K.

Description

A novel adaptive binary decoding algorithm for LDPC codes is proposed, which reduces the decoding complexity while having a comparable or even better performance than corresponding non-adaptive alternatives. In each iteration the variable node decoders use the binary check node decoders multiple times; each single use is referred to as a sub-iteration. To process the sequences of binary messages in each iteration, the variable node decoders employ pre-computed look-up tables. These look-up tables as well as the number of sub-iterations per iteration are dynamically adapted during the decoding process based on the decoder state, represented by the mutual information between the current messages and the syndrome bits. The look-up tables and the number of sub-iterations per iteration are determined and optimized using density evolution. The performance and the complexity of the proposed adaptive decoding algorithm is exemplified by simulations.
5 pages, 4 figures, to be published at ISIT 2009