A Density Adaptive Routing Protocol for Large-Scale Ad Hoc Networks

Position-based routing protocols use location information to refine the traditional packet flooding method in mobile ad hoc networks. They mainly focus on densely and evenly distributed network scenarios, but their performances degrade quickly as networks become sparse. To overcome these shortcomings, we introduce the network density concept in the routing process, and propose a density adaptive routing protocol (DAR) to optimize the packet forwarding process. DAR algorithm utilizes the local network density to determine the packet forwarding zone; in dense areas, it narrows the forwarding range to reduce the total number of participants in flooding; in sparse area, it enlarges the forwarding scope to enclose enough nodes for packet relaying. Compared to the existing protocols, DAR yields lower flooding overhead and higher route discovery rate. Theoretical analysis proves that it works well in both densely and sparsely distributed network scenarios, and is more scalable than traditional routing protocols. Simulation results are presented in this paper to demonstrate the effectiveness of the proposed protocol.