Modified Directional Medium Access Protocol using Bootlace Lens

In this paper, a directional MAC protocol based on bootlace lens: a multiple beamforming network, is proposed and evaluated. The existing directional MAC (DMAC) protocols employ omnidirectional antenna to listen and switch to the directional mode for communication. The directional antennas allow spatial reuse and increased communication range. Omnidirectional antennas lead to hidden terminal problems, deafness, limitation of the communication range and decrease in overall utilization of the channel. The modified DMAC (MDMAC) proposed in the present work employs a set of directional antenna system that work in the directional mode only. The channel is sensed by a set of three directional antenna systems based on bootlace beamforming networks each covering an angular space of 120deg. Simulation results indicate that DMAC protocol based on bootlace lens gives higher throughput as compared to the basic DMAC protocol and IEEE 802.11 MAC protocol. The problem of hidden terminals does not exist and the problem of deafness is largely obviated