Interconnection Network for Structured Low-Density Parity-Check Decoders

Most structured codes use the group-and-permute design approach in which rows and columns are divided into groups of the same size. Row/column groups and individual row-column are connected by some permutation. A general group-and-permute decoder requires an interconnection network for group-to-group communication. In this paper we suggest the use of self-routed Benes networks based on the communication pattern of LDPC codes. Bipartite edge coloring is used to schedule messages such that there are no switch network output conflicts. The looping routing algorithm for Benes networks is used to compute switching codes. Both scheduling information and switching codes are pre-computed and stored for each design code since they do not change in the lifetime of the code