Best-response team power control for the interference channel with local CSI

We study in this paper1 the problem of binary power control in interference channels with single-antenna nodes. In many practical scenarios, letting transmitters (TXs) exchange the locally available channel state information (CSI) is unpractical. In such cases, coordinating the power allocation is a difficult problem and we propose in this work a novel binary power control policy for maximizing the ergodic sum-rate when each TX has only access to the instantaneous channel realization of the direct channel to its own user. We prove rigorously the intuitive result that the optimal binary power control policy consists in letting each TX transmits with full power if and only if the realization of this direct channel is above a threshold. The power control policy obtained with the algorithm is a “best-response” power control policy and allows to achieve benefits of coordinated power allocation at a low cost in terms of backhaul resources and complexity.