A low-complexity IRA-LDPC coded noncoherent unitary space-time modulation system on Rayleigh flat fading channel

This letter constructs a practical low- complexity coded modulation MIMO system which concatenates the IRA-LDPC codes based on the permutation Q-matrix with the noncoherent unitary space-time modulation (USTM) based on sine-cosine function for Rayleigh flat fading channel. In the receiver, we adopt dual detecting scheme: first relative coarse low complexity ML detect and then relative precise MAP detect with shrinking search range of constellation points. Combining the dual detecting scheme with the Belief-Propagation (BP) iterative decoding algorithm comes into being an iterative feedback demodulate-decoding system. The IRA-LDPC coded modulation system can obtain about 15 dB coding gain at 10
^-5
BER over the uncoded USTM system. Some results are based on simulation testing.