Expectation Propagation Detection With Physical Network Coding for Massive MIMO Systems

Both massive multiple-input and multiple-output (MIMO) and physical-layer network coding (PNC) techniques can effectively improve the network throughput. However, for PNC-aided massive MIMO systems, the high-order modulations superimposed at the relay particularly bring computational burden and performance degradation to the signal detection. Thus, this letter proposes an iterative MIMO-PNC detector from double expectation propagation (DEP) as a high-accuracy solution in this large-scale system. By exploiting the PNC characteristic, the summation and difference (SD) information of the user pair messages are first linearly formed and iteratively updated between the DEP detector and the channel decoder. Simulation results show that the proposed iterative method can achieve significant performance gains of 2 dB in various massive MIMO systems, as compared to the non-iterative one and traditional linear minimum mean square error (LMMSE) detector.