Small World Based Cooperative Routing Protocol for Large Scale Wireless Ad Hoc Networks

Scalability of routing protocols is one of the most important open problems in large scale wireless networks. In this paper, a routing protocol for large scale wireless network, called as SCR (Small-world based Cooperative Routing protocol), was proposed based on the small world phenomenon and cooperative communication. In SCR, each source node selects its short-cut node, through which the path length to the destination node is greatly reduced. The cooperative communication link is formed to decrease the hops between the sender node and its short-cut node to match the small world phenomenon. We show that in a network with nXn nodes, the average path length of SCR is O [n log n)/[Mq)], 1≤q≤log n, where M is the number of cooperative nodes. If the average hops between the sender node and its short-cut node is approximately equal to one hope by using the cooperative communication link, the average path length of SCR is O[(log n)²/q] . Compared with other existing routing protocols, the SCR has much shorter path length and low routing overhead.