Geographic based opportunistic routing for cognitive radio ad hoc networks

Most existing routing protocols for CR ad hoc networks attempt to build a stable and reliable route for data transmission. However, establishing such a route for a whole flow is usually not possible due to the instability and unpredictability of channel conditions in CR environment. In this paper, we discuss a geographic based opportunistic routing protocol for CR ad hoc networks. The problem of our concern is: given a set of CR nodes with geographical positions and temporarily available channels, how to design a protocol so that the average number of transmissions per packet is minimized. We propose a novel routing protocol where packets are transmitted through successively geographic closer intermediate destination nodes, until eventually destination is reached. The intermediate destination nodes are within a two-hop neighborhood and locally chosen by a heuristic algorithm we develop. We also propose an algorithm for selecting the operating channel for opportunistic routing. Extensive simulations are conducted to show the performance of our protocol.