Spatially-coupled codes for side-information problems

For compound LDGM/LDPC codes with maximum a posteriori (MAP) processing, Wainwright and Martinian showed that the information-theoretic rate regions of the Wyner-Ziv (WZ) and Gelfand-Pinsker (GP) problems are achievable. For the same ensemble, these rates do not appear to be achievable with message-passing guided decimation (GD). Fortunately, spatially-coupled (SC) codes seem to provide an elegant remedy when iterative decoding falls short of MAP decoding. In particular, Aref et al. recently introduced SC LDGM codes that approach the rate-distortion region with belief-propagation guided decimation (BPGD). In this paper, we show that SC compound LDGM/LDPC codes with BPGD can approach the rate regions of the WZ and GP problems.