Joint relay selection and power allocation for pairwise multi-way relay networks

We consider a multi-way relay network in which all source nodes share their data by the help of multiple single-antenna relay nodes. To mitigate a loss in the spectral efficiency, the network employs a pairwise digital network coding (DNC) which pairs the source nodes for simultaneous transmission so that the relay forwards the DNC bits of the pairs. For the network, we devise a joint relay selection and power allocation (RS-PA) scheme based on an approximation on the instantaneous symbol error probability incorporating error propagations. Simulation results show that the network with the proposed RS-PA outperforms the conventional network with the RS only with a larger gain with a larger number of relays.