Optimization techniques for two-way relaying based multiuser multiplexing

We propose an optimization technique for the use of two way relays to forward signals and perform spatial multiplexing. The multiuser transmitter and receiver pairs employ single antennas, however, the two way relays can be used to forward signals to each other while performing spatial multiplexing by appropriately changing the phase and the amplitude of the signals at the relays. The problem has been formulated into a semidefinite programming (SDP) framework that can be solved using interior point methods. The simulation results demonstrate that the proposed technique has the ability to perform spatial multiplexing using two way relays for a wide range of target signal to interference and noise ratio requirements.