The Benefits of Directional Antennas in Heterogeneous Wireless Ad-Hoc Networks

Basic properties of wireless ad-hoc networks, such as connectivity, have traditionally been analyzed and evaluated under the assumption that all nodes have homogeneous communication capabilities. While this assumption usually holds for small networks, it is unlikely to be true in most large scale networks. This paper studies how heterogeneous communication capabilities affect basic properties of ad-hoc networks. More specifically, we consider one type of heterogeneity in which nodes are equipped with two different types of antenna technologies, omni-directional and directional, and evaluate them against four properties: network connectivity, energy consumption, interference tolerance and resilience to failures. Our main results show that even under a very simple network model that does not assume any global knowledge of the network, an ad-hoc network where only 10% to 20% of the nodes are equipped with directional antennas, can outperform a comparable homogeneous network (where all nodes have only omni-directional antennas) in all four metrics.