Repeat-accumulate codes for block-fading channels

We design systematic and regular repeat-accumulate (RA) codes for non-ergodic block-fading channels. An encoder structure of RA codes for block-fading channels with an arbitrary number of fading blocks is proposed. Simulation results show that the proposed RA codes achieve full-diversity word error rate (WER) performance over block-fading channels. In addition, the WER performance of the proposed RA codes is superior to the root-low-density parity-check (LDPC) and repeat and blockwise accumulate (RBA) codes. Furthermore, the gap from the outage probability remains constant with increasing block length for the proposed RA codes. Besides an easy encoding structure, the proposed RA codes have notably less ones in the parity-check matrix compared to corresponding root-LDPC codes. Therefore, the decoding complexity of the proposed RA codes is significantly less than the corresponding root-LDPC codes.