Capacity Improvement of Wireless Ad Hoc Networks with Directional Antennae

This paper investigates the scale law of network capacity of wireless ad hoc networks with phased array antennae and demonstrates its dramatic improvement over that with omni-directional antennae. The contributions of this paper are three-fold. First, we establish a general interference model for directional antennae of generic antenna patterns. Second, we argue that an arbitrary directional antenna pattern can be approximated by that of a phased array antenna. We investigate wireless networks with phased array antennae and derive the impact of nulls and null width in the antenna pattern on the scalability of network capacity. Third, we introduce a novel analytical approach that gives rise to a new set of network-capacity upper and lower bounds when directional antennae are used. We believe that this is the first work that shows that Theta(n) scalability in network capacity is achievable provided the dimension of the antenna array is sufficiently large