Joint network coding and beamforming techniques for downlink channels

We propose a joint optimization of Network Coding and MIMO techniques to improve the downlink channel throughput of a wireless base station. Specifically, we consider a MIMO base station with multiple transmit antennas that serves multiple users simultaneously by generating multiple signal beams with well-defined beamforming weight vectors where each beam intends for a particular user. Given a large number of users and a small number of transmit antennas, a base station must decide, at any transmission opportunity, which group of users it should transmit packets to, in order to maximize the overall throughput. To that end, we propose a method for grouping users that takes advantages of NC technique and the orthogonality of user channels to improve the overall throughput on both unicast and broadcast transmissions. Our simulation results indicate that the proposed method can efficiently increase the throughput over existing techniques, especially in highly lossy environments.