For a multi-user interference channel with multi-antenna transmitters and single-antenna receivers, by restricting each receiver to a single-user detector, computing the largest achievable rate region amounts to solving a family of non-convex optimization problems. Recognizing the intrinsic connection between the signal power at the intended receiver and the interference power at the unintended receiver, the original family of non-convex optimization problems is converted into a new family of convex optimization problems. It is shown that, for such interference channels with each receiver implementing single-user detection, transmitter beamforming can achieve all boundary points of the achievable rate region.
@article{arxiv.0908.3171,
title = {On the Optimality of Beamforming for Multi-User MISO Interference Channels with Single-User Detection},
author = {Xiaohu Shang and Biao Chen and H. Vincent Poor},
journal= {arXiv preprint arXiv:0908.3171},
year = {2009}
}