Average Coset Weight Distribution of Multi-Edge Type LDPC Code Ensembles

Multi-Edge type Low-Density Parity-Check codes (METLDPC codes) introduced by Richardson and Urbanke are generalized LDPC codes which can be seen as LDPC codes obtained by concatenating several standard (ir)regular LDPC codes. We prove in this paper that MET-LDPC code ensembles possess a certain symmetry with respect to their Average Coset Weight Distributions (ACWD). Using this symmetry, we drive ACWD of MET-LDPC code ensembles from ACWD of their constituent ensembles. key words: average coset weight distribution, low-density parity-check codes, multi-edge type low-density parity-check codes, symmetry, weight distribution