Cross-Layer Diversity and Scheduling Optimization for Interference-Limited MIMO Ad Hoc Networks

In this paper we study the problem of reliable transmission in interference-limited MIMO networks. This is motivated by a fundamental tradeoff between scheduling full diversity non-interfering links vs. scheduling interfering links using lower diversity gain in conjunction with nulling. First, we formulate a distributed cross-layer optimization problem that jointly decides the scheduling, diversity gain and nulling in order to minimize the probability of error of individual links subject to signal-to-interference-and-noise-ratio (SINR) constraints. Second, we characterize the optimal solution for 2 links. It reveals simple decision rules that constitute the basis for solving the problem for arbitrary number of links using Scheduling Space-time coded Links (SSL) algorithm. Numerical results exhibit significant improvement over scheduling non-interfering links with full diversity gain.