Energy Efficient Two-Way Non-Regenerative Relaying for Relays with Multiple Antennas

Energy efficient beamforming is studied for a MIMO two-way non-regenerative relaying system with multi-antenna users and a multi-antenna relay. The resulting optimization problem is non-convex. A Dinkelbach based alternating maximization (DAM) method is proposed to achieve an iterative design of the relay amplification matrix and the beamforming vectors at the users.