Bisplinghoff, A.; Schmauss, B. (University Erlangen, Germany)
Langenbach, S. (Cisco Optical GmbH, Nuremberg, Germany)
We investigate the impact of frequent phase slips on turbo decoding of low density parity check codes combined with differentially encoded QPSK. Iterative joint soft differential demodulation and soft-decision decoding improves the signal to noise ratio performance of coherently demodulated QPSK, but compromises its phase slip resilience.