A novel adaptive MAC protocol for wireless internet access network with smart antennas

Employing smart antennas in the Central access point (CAP) of wireless Internet access networks is studied. Based on the characteristics of the networks and smart antennas, a Polling-based Adaptive beamforming multiple access protocol (PB-ABFMA) is proposed. In PB-ABFMA, the CAP requests the corresponding Mobile terminal (MT) to transmit training sequence just before the data packets transmission, so the Temporal reference beamforming (TRB) can be performed by the smart antennas. The CAP schedules packet transmissions based on the polling mechanism and dynamic TDMA, and a mini-slot is used to keep connectivity when an MT is idle, therefore, the access delay is reduced. Meanwhile, a simple and effective access method is proposed to guarantee rapid access of new arrival MTs to the channel. Based on the "request-reply" traffic, which is the main traffic in Internet, the theoretical analysis of channel utilization and mean turn-around delay is presented. Analysis and simulation results show that the proposed PB-ABFMA protocols effectively support the application of smart antennas and provide high channel utilization and low turn-around delay.