New evolution in two-way relay networks based on physical layer network coding

In this paper, a physical-layer network coding (PNC) method is offered for a two-way relay network with spatial modulation (SM) for source node and relay node. For this purpose, we consider a two-way relay network consists of a single relay node and two source nodes both equipped with multiple antennas. It includes two source nods for transferring the data through SM and also, the relay node for decrypting coded packet network (through the XOR) of two packets received from the source node. In the proposed method, the signal detection approach with maximum-likelihood for the PNC with SM modulation is used for relay nodes. The simulation results show that the bit error rate (BER) in the relay node of the proposed method is significantly improved compared to the conventional method PNC; while the data rate is based on the same BER. It is worth mentioning that the performance of the proposed method, when the number of antenna nodes rises, is significant. And it leads to increase in the data rate which indicates that the proposed method will be much convenient for the next generation of wireless communication systems, especially the fifth generation. It should also be said that the suggested SM-based PNC method, does not need channel state information at transmitter. So it can be easily implemented in practice.