| The capacity of wireless network is constrained by the physical channel capacity and the interference from neighboring nodes. Gupta etc have shown that in an arbitrary network with n nodes, the upper bound for per-node throughput capacity reduces quickly with the increase of the number of nodes in the network, and even lower under a random network. Directional antennas, especially those with multi-beam forming capabilities, provide higher bandwidth and reduced interference area, which lead to elevated capacity bounds and improved performance. In this paper, we first present a study on the capacity bounds of ad hoc networking with directional antennas, including hybrid antenna patterns that are a mix of multi-beam forming and single-beam forming. We prove that adaptive multi-beam forming system further improves the network capacity over the single-beam directional networks, due to its desirable features of multiple trans-mission/reception and anti-interference beam-forming.
Then we further investigate the performance of adaptive multi-beam directional networking with regard to the prevalent Medium Access Control (MAC) protocols, namely, TDMA and CSMA/CA, under basic network to-pology assumptions. The results show that using adaptive multi-beam antennas can improve the network throughput by multi-fold depending on the number of beams, thus providing an effective means to achieve high data rate and reliable communication for future combat systems.
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