Low-Density Parity-Check Codes for Two-Way Relay Channels

In this paper, we propose Low-density Parity-check (LDPC) codes for two-way relay channels, where two sources communicate with each other through a relay. At the relay, a simpler interference cancellation joint decoder decodes for the multiple access phase of two-way relay channels. Then, the relay codeword is encoded from two decoded source codewords with LDPC codes. At source, a sub-optimal belief propagation decoder decodes message from codewords received from the relay, the other source and its own source. Simulation results are given to show that our proposed simpler interference cancellation joint decoder at the relay is only 0.2 dB away from the existing sub-optimal belief propagation joint decoder. The required Eb/No at the source is 1.5 dB less than that of the single user channel with the same bit error rate (BER).