Asympotic capacity bounds for ad-hoc networks revisited: the directional and smart antenna cases

Directional and smart antennas can be useful in increasing the capacity of wireless ad hoc networks. A number of media access and routing protocols have been recently proposed for use with such antennas, and have shown significant performance improvements over the omni-directional case. However, it is important to explore if and how different directional and smart antenna designs affect the asymptotic capacity bounds, derived by Kumar and Gupta [11]. These bounds are inherent to specific ad-hoc network characteristics, like the shared nature of the wireless media and multi-hop connectivity, and may pose major scalability limitations for such networks. In this paper, we look into how directional and smart antennas can affect the asymptotic behavior of an ad-hoc network’s capacity. Specifically, we perform a capacity analysis for an ideal flat-topped antenna, a linear phased-array antenna, and a fully adaptive array antenna model. Finally, we explain how an ad-hoc network designer can manipulate different antenna parameters to mitigate the scalability problem of ad-hoc networks. Keywords-component; — capacity; ad-hoc; directional antennas; smart antennas;