Multiple Access Protocol for Mobile Ad Hoc Network with Smart Antennas
Jian Li · Chinese Journal of Computers · 2003
The approach to employ smart antennas in mobile ad hoc network (MANET) nodes is presented, and an adaptive beamforming CSMA/CA protocol (ABF-CSMA/CA) is proposed. In ABF-CSMA/CA, RTS/CTS dialogue is used to distribute channel reservation information. Training sequences are placed in RTS and CTS packets, so the temporal reference beamforming (TRB) can be performed by the source node and the destination node. An improved virtual carrier-sense mechanism is also proposed to enhance collision avoidance (CA) and obtain efficient space division multiple access (SDMA). In this scheme, every node has two kinds of network allocation vector (NAV). An oNAV maintains the interval of ongoing transmission of neighbors whose smart antennas operate in omnidirectional mode, and multiple bNAVs maintain those intervals of neighbors whose smart antennas operate in beamforming mode. Theoretical analysis of channel utilization is presented. Results show that ABF-CSMA/CA protocol combining with smart antennas can provide higher channel utilization.