Blockwise Noncoherent AWGN Channel: Concatenated Codes and Composite Capacity

We consider binary phase shift keying (BPSK) over an additive white Gaussian noise (AWGN) channel with constant, but unknown carrier phase over blocks of nI channel symbols and a concatenated coding scheme. The composite capacity of the channel constrained to specific binary inner codes, i.e. codes with good minimum distance properties, is derived. The outer code is chosen from the ensemble of non-binary regular (2, dc) low-density parity-check (LDPC) codes with fixed variable node degree of 2 and check node degree dc. Iterative decoding thresholds obtained by means of density evolution are provided for several concatenations of inner and outer codes and are compared with capacity results.