Multi-pair physical layer network coding with beamforming systems

In this paper, we propose a spatial multi-user physical layer network coding (SM-PNC) scheme by jointly utilizing PNC and beamforming techniques in a multi-user one relay communication system. The relay is equipped with multiple antennas and each user node is only equipped with a single antenna. The two way relay transmission consists of two phases. In multiple access phase, the summation and difference of the user data are combined with log likelihood ratio combination, which has a superior robustness to the traditional separation detection under any channel condition; In broadcast phase, optimal adaptive select-group broadcasting scheme is proposed, which can efficiently overcome the problem of near interference in beamforming. Simulation results validate the ability of the proposed algorithms.