Pseudocodeword Weights for LDPC Codes under Differential PSK Transmission over the Noncoherent AWGN Channel

This Letter considers the finite-length analysis of iterative decoding of low-density parity-check codes under differential binary-phase-shift-keying (DBPSK) and differential quadrature-phase-shift-keying (DQPSK) over the noncoherent additive-white-Gaussian-noise channel. Specifically, we derive the weight of the pseudocodewords of a Tanner graph under these signaling schemes and use them to explain the difference in error performance between coded DBPSK and coded DQPSK.