MIMO relay design for multiple link pairs based on SINR constraints

We address the problem of multiple-input multiple-output (MIMO) relay design for multiple distributed source and destination pairs with signal-to-interference-plus-noise-ratio (SINR) constraints. Multiple link pairs communicating through a relay can be beneficial in the wireless digital home network (DHN) scenario where various equipments exchange or share digital media contents. In the first hop from the source nodes to the relay, cooperative transmit-receive beamforming design is performed to maximize SINR at the relay. Then joint power allocation and transmit-receive beamforming is conducted in the second hop from the relay to the destination nodes based on the SINR constraints for each link pair. The beamforming filter is a group maximum SINR filter which exploits intra-group cooperation. The group-based uplink-downlink duality property in downlink channel is adopted and modified for amplify-and-forward (AF) relaying. An iterative algorithm is then proposed to solve the problem. Simulation results show the superiority of the proposed algorithm over other methods.