Spatial Multiplexing Gains for Realistic Sized Ad Hoc Networks with Directional Antenna Arrays

Abstract

We concentrate on an ad hoc network model with nodes on integer lattice points over a 2D plane. We examine the limits of ad hoc network performance for systems with antenna arrays capable of allowing both spatial multiplexing and directional processing. Two cases are considered. In the first case, we consider "perfect" directional antenna arrays, in other words, each node can form beams of infinitesimally narrow beamwidth. In this case, the throughput capacity of an ad hoc network is independent of the network size. In the second case, we consider a more practical system where each node can form a fixed number of beams of finite beamwidth. Our results show that the spatial multiplexing gains depend on the system size, antenna beamwidth, and number of antenna beams. Furthermore, we show that spatial multiplexing gains offsetting the interference-related performance degradation can be achieved in ad hoc networks with thousands of nodes.