Performance of Repeat-Accumulate Codes (RAC) for decode-and-forward wireless relay channel

Repeat-Accumulate Codes (RAC) are one of alternative choice code besides turbo codes and low-density parity-check (LDPC) codes. This paper presented decode-and-forward protocol for wireless relay channel by utilizing repeat-accumulate codes as the coding scheme in the relay. The main advantages of the RAC over another code that makes the RAC is more considered for this research are the complexity of encoding is linear in the code length, have a simpler design, and easier to combine with modulator or detector. Simplicity is the main factor for using RAC in this research because in the multihop wireless communication concept, the information processing that occurs in every node or in every relay should not be complicated. In this paper, RAC is employed in wireless relay channel for the LOS model and urban model. The result shows that in the LOS model, RAC only show BER improvement when the relay position is exactly in the mid between information source (S) and destination (D). In urban channel model, the BER improvement can be observed, whether the relay is positioned ¼, ½ or ¾ between the information source (S) and the destination (D).