Coded cooperation in asymmetric two-way relay networks

This paper investigates asymmetric two-way relay networks, where a pair of source nodes exchange data with the help of a relay node. Coded cooperation scheme using nonbinary LDPC codes is proposed for improving the performance of such networks. In our scheme, the relay transmits different length of parity check information with different modulation orders simultaneously by nesting the low order constellation as a subset of the high order constellation. Thus the relay link with higher SNR can transmit more parity check information to improve the joint decoding performance. Simulation results show that the proposed scheme effectively improves the block error rate of both sources.