Interference-Aware Sector Design in IEEE 802.11ad Networks

Abstract

IEEE 802.11ad is the first standard capable of delivering Gigabit capacities in a WLAN setting by exploiting mmWave frequencies. Its key innovation is the Sector Level Sweep, a procedure for establishing directional links over mmWave by sweeping over a pre-computed set of phased-array antenna sectors. Crucial to the performance of IEEE 802.11ad networks and involving an exponentially-large search space, the sector design is left open to implementation. As a result, several sector designs have been introduced that are aimed at maximizing the SNR of a given direct link while ignoring the interference projected to other links. If highly competitive in small deployments, a sector design that does not take interference into account can lead to poor overall performance in multi-AP deployments.In this article we present IASSEN, the first approach to Interference-Aware Sector deSign in IEEE 802.11ad Networks. Anchored in an intimate understanding of COTS 802.11ad hardware, IASSEN models the SINR for each network link as function of the low-level parameters driving the sector design. After modeling the problem of interference-aware sector design as an integer nonlinear programming problem, IASSEN introduces a heuristic carefully combining a quick convergence to a local optimum with an approach for avoiding poor local optimum points. A simulation study using measurement-based and realistic sector patterns shows that IASSEN improves overall network performance by as much as 100% when compared to state-of-the-art approaches that do not take interference into account.