Transmitter-receiver and relay optimisation for spectrum sharing multiple-input and multiple-output peer-to-peer users

The authors investigate a spectrum sharing peer-to-peer relay network where multiple source nodes with multiple antennas communicate with their desired destination nodes with multiple antennas through a multiple-input and multiple-output (MIMO) relay. The authors establish the duality between uplink and downlink peer-to-peer MIMO channels with any number of antennas at each node and demonstrate mean square error (MSE) of a downlink peer-to-peer network can be achieved in a virtual uplink network with the same total network transmission power constraint. By applying this result, the authors develop an iterative algorithm to optimise the source, relay and receiver processing matrices such that the weighted MSE of the retrieved signal at the receivers is minimised. The simulation results demonstrate satisfactory performance of the proposed algorithm.