Physical network coding for bidirectional relay MIMO-SDM system

Physical-layer network coding (PNC) is a promising technique to increase transmission throughput over bidirectional relay wireless networks. In this paper, based on the work by Zhang and Liew, we propose a new scheme called multiple input multiple output spatial division multiplexing PNC (MIMO-SDM-PNC). By using MIMO-SDM, the proposed scheme achieves double multiplexing gain and also does not require that the end nodes know the information about the forward channel from the source nodes to the relay. Compared with the system by Zhang and Liew the proposed system achieves the same diversity order. The MMSE based detection was shown to have equivalent BER performance with that of the MIMO-PNC while the ZF based suffers about 2.4 dB power loss due to noise amplification problem.