Optimized signal-space alignment for physical-layer network coding over distributed MIMO system

We study an uplink distributed multiple-input multiple-output (D-MIMO) system, where multiple users are served by multiple base stations (BSs) connected to a common central unit (CU) via independent backhaul links. We propose an optimized signal-space aligned network coding transceiver scheme for sum-rate maximization. In the scheme, the signal alignment pattern and computed message combinations are determined by a carefully designed indicator matrix. Linear precoding operations at users are applied to realize the signal-space alignment. The aligned spatial streams at BSs are used to generate message combinations. We jointly optimize the alignment pattern and linear precoding operations to achieve a higher sum rate. Numerical results demonstrate the superiority of our proposed scheme over other benchmark schemes.