Towards Scheduling MIMO Links in Interference-Limited Wireless Ad Hoc Networks

In this paper we study the problem of MIMO-MAC resource allocation in interference-limited multi-user scenarios. The prime motivation is to balance the inherent trade-off between maximizing the individual link data rate, using spatial multiplexing techniques, and suppressing interference, using nulling techniques. First, we formulate a cross-layer optimization problem that jointly decides the scheduling and MIMO stream allocation in order to maximize the average sum link rate for a given set of single-hop links, subject to signal-to-interference-and-noise-ratio (SINR) constraints. Second, we characterize the optimal solution for the case of 2 interfering links. Numerical results reveal interesting insights about the trade-off and interference scenarios where naive TDMA could still outperform slot sharing from the average sum link rate perspective.