An Adaptive Multiple Access Protocol for WLAN Equipped with Smart Antenna

The use of smart antenna to extend the coverage range and capacity of wireless local area networks (WLAN) dictates the employment of novel multiple access protocols, with which the access point (AP) can provide access to remote stations. In this paper, we propose an adaptive multiple access protocol for WLAN with smart antenna. To efficiently support the differentiation of the stations residing within the broadcasting coverage range of the AP from those residing out of the range, the proposed protocol uses the hybrid superframe structure of contention-free period and contention period. Moreover, our protocol can adaptively adjust the antenna mode between beamforming and broadcasting according to the beam width and the number of active stations in the service area. Using simulation we compared the adaptive protocol with other non-adaptive ones. The results show that constructing our adaptive protocol by switching among non-adaptive protocols turns out to be the best strategy which allow us to take advantage of the best protocol providing low delay and high throughput.