Adaptive control of the antenna beam

Smart antennas provide electronically control of beam direction depending on the situation and exchange data with another node in a given direction．It can prevent the interference and improve the spatial utilization of wireless channel．However, smart antennas can extend communication range, so as to reduce number of hops．Moreover, inter-flow interference leads to a decrease in simultaneous communication and intra-flow interference incur the directional hidden terminal and deafness problems．Therefore, to design a directional MAC protocol to make use of smart antennas, challenges is controlling directivity．
We have proposed a new MAC protocol called DMAC/BA for ad-hoc networks using smart antennas to be fully harnessed the potential of smart antenna in mobile environment．DMAC/BA had superiority characteristics, adaptive beam-width control, in comparison with the conventional protocols and showed that has been observed to maintain high throughput in a changing environment.