On wireless ad hoc and sensor networks with directional antennas: Efficient collision and deafness avoidance mechanisms

Wireless ad hoc networks allow anywhere, anytime network connectivity with complete lack of central control, ownership, and regulatory influence. Medium Access Control (MAC) in such networks poses extremely timely as well as important research and development challenges.; Nevertheless, using directional antennas in wireless ad hoc networks introduces some other serious challenges, the most critical of which are the deafness and hidden terminal problems. This thesis first thoroughly discusses and examines the benefits of using directional antennas and the techniques used to efficiently utilize directional transmissions. Secondly, this thesis proposes Directional MAC with Deafness Avoidance and Collision Avoidance (DMAC-DACA) scheme to address the deafness and hidden terminal problems in wireless ad hoc networks with directional antennas. Finally, a directional communication extension of ns2 network simulator is proposed and implemented to enable the simulation of wireless ad hoc and sensor networks with directional antennas. With this extension, a comprehensive performance evaluation study is conducted to evaluate the performance of DMAC-DACA. Simulation results show that DMAC-DACA significantly alleviates the deafness problem and remarkably improves the performance of wireless ad hoc networks. Moreover, through simulation, this thesis also investigates the impact of deafness and hidden terminal problems on the performance of wireless ad hoc networks. (Abstract shortened by UMI.)...