Efficient modulation and coding scheme based on low-density parity-check codes

A repetition coding can provide coding and diversity gains, however, the transmission rate is severely decreased. Therefore, the repetition diversity scheme has been recognized as an inefficient coding technique. In the paper, we present some performance results of LDPC codes with a repetition coding over AWGN and Rayleigh channels for given transmission rates. Simulation results show that the repetition scheme with QPSK modulation always provides a good coding gain over a Rayleigh fading channel due to diversity effect, as compared with the case of BPSK modulation without repetition. Furthermore, we observe the performance of LDPC coded modulation with non-uniform constellation over AWGN and Rayleigh channels. Finally, we present that the best modulation and coding strategy for given channel condition can be determined by adjusting code-rate, modulation and repetition schemes.