Beamforming Optimization and Power Allocation for MIMO Asymmetric Multi-Way Relay Channels

A multiple-input multiple-output (MIMO) multi-way relay channel, where a single base station exchanges independent messages with K users via a relay station, is considered. We propose an iterative beamforming optimization algorithm based on orthogonal projection with signal subspace alignment. Moreover, an optimal power allocation is also designed to maximize the system sum rate. Performance evaluation shows that the proposed scheme produces significant improvement and offers higher sum rate than the existing scheme.