An efficient MAC protocol with direction finding scheme in wireless ad hoc network using directional antenna

In this paper, we propose an efficient directional MAC protocol with direction finding scheme for wireless ad hoc network. This efficient directional MAC protocol uses the receiver-oriented direction-finding scheme, where each node n periodically collects its neighborhood directional information and forms an angle-signal table (AST). Directional DATA/ACK packets are transmitted, after the omni-directional RTS/CTS which not only inform the hidden nodes of on-going communication status and but also are especially effective for the string topology in ITS (Intelligent Transportation System). This omni-directional RTS/CTS can be issued without disturbing the neighbors´ on-going communication, by the utilization of DNAV (directional network allocation vector) with the angle information from AST. Simulation results in highway traffic scenarios show the performance improvements by this proposed directional MAC scheme conjunct with the equalized receiver sensitivity and receiver threshold.