Capacity of hybrid wireless networks with directional antenna and delay constraint

Abstract

We study the throughput capacity of hybrid wireless networks with a directional antenna. The hybrid wireless network consists of n randomly distributed nodes equipped with a directional antenna, and m regularly placed base stations connected by optical links. We investigate the ad hoc mode throughput capacity when each node is equipped with a directional antenna under an L-maximum-hop resource allocation. That is, a source node transmits to its destination only with the help of normal nodes within L hops. Otherwise, the transmission will be carried out in the infrastructure mode, i.e., with the help of base stations. We find that the throughput capacity of a hybrid wireless network greatly depends on the maximum hop L, the number of base stations m, and the beamwidth of directional antenna θ. Assuming the total bandwidth W bits/sec of the network is split into three parts, i.e., W1 for ad hoc mode, W2 for uplink in the infrastructure mode, and W3 for downlink in the infrastructure mode. We show that the throughput capacity of the hybrid directional wireless network is Θ(nW1/ θ2L log n})+Θ(mW2), if L=Ω(n 1/3/θ4/3log2/3 n) and Θ(θ2L2 log n)W1)+Θ(m W 2), if L=o(n1/3/θ4/3 log2/3n), respectively. Finally, we analyze the impact of L, m and \theta on the throughput capacity of the hybrid networks. © 2010 IEEE.