Scalable Random Cooperation Routing protocol for large-scale wireless sensor networks

Scalability is a key factor in designing routing protocols for large-scale extended wireless sensor networks. The bottleneck problem of scalability is how to cut down the average path length with tolerable overhead. In this paper, a scalable routing protocol for large-scale wireless sensor networks, referred to as SRCR (Scalable Random Cooperation Routing protocol), is proposed based on the small world theory and cooperative transmission. In SRCR, each node finds its friends to match the small world phenomenon by using a distributed algorithm. Specifically, long range cooperative links are established between a node and its friends through cooperative transmission. Benefit from both friends and the cooperative links, the average path length is reduced significantly. We show that in a network with N nodes uniformly distributed in an square region, the average path length of SRCR is asymptotically O(log₂ √N)², while the routing overhead is acceptable. Simulation results show that SRCR performs better than some other protocols, considering end-to-end delay, network throughput, and routing overhead together.