Position Based Directional Ad-Hoc Routing with Space Time Diversity

Self organizing mobile Ad-Hoc networks have gained much attention in the last decade particularly due to their ease of deployment in war zones and natural disasters. Because of the fact that the Ad-Hoc network is a virtual network created by the participating nodes, this approach can be applied to remote areas with no fixed networking capability, and is ideal for coordination in remote locations. Considering the sophistication of equipment capable of handling MIMO techniques and inbuilt GPS receivers, a simple two-stage method of forwarding the message is proposed in this paper. A low frequency broadcast containing GPS coordinates of the nodes is used for node discovery which is then followed by a directional narrow beam at higher frequency for data transfer. The knowledge of GPS location combined with directional transmission is expected to increase the performance of the network. The intent of the paper is to propose a simplified location-based Ad-Hoc routing mechanism and to examine its performance when combined with MIMO space time coding technique. The space time codes are evaluated over a Flat Slow Fading channel using various modulation schemes. The basic premise of the proposed scheme is simplicity and robustness.