Path Selection and Adaptive Selection of Smart Antenna Transmission Schemes in Multi-hop Wireless Networks

The performance of multi-hop wireless networks can be substantially improved by using smart antennas. However, the utilization of smart antennas is quite challenging as the benefit of the different transmission modes strongly depends on specific channel conditions. In this paper we present a novel path selection protocol PSPSA (path selection protocol for smart antennas) and a modified MAC protocol that exploits the benefits of smart antennas. PSPSA selects an optimum path considering the specific ranges and transmission rates implied by the different transmission schemes (spatial multiplexing and beamforming). The MAC protocol is a modification of the traditional DCF scheme to cope with the different PHY layer transmission schemes. Our solution enables mesh nodes to dynamically select their transmission scheme on a per packet basis according to the current channel conditions. Simulation results show that the overall packet success rate (throughput) of multi-hop wireless networks are substantially improved.