Adaptive packet forwarding region based three dimensional real-time geographical routing protocol (3DRTGP) for wireless sensor networks

In this paper, a novel 3D real-time geographical routing protocol (3DRTGP) for wireless sensor networks (WSNs) is presented. This protocol controls the number of forwarding nodes by adapting a unique packet forwarding region (PFR) selection algorithm based on network density. This algorithm reduces the number of redundant packet transmissions, collisions, and congestion, which in turn, enables it to meet realtime application requirements, i.e., packet delivery within a specified deadline. In order to make 3DRTGP viable, we provide a solution for void node problem (VNP) in 3D deployments. In this protocol, the forwarding decision in a node depends on the expected number of hops towards the destination and the queuing delay in the forwarding node. Additionally, 3DRTGP does not require explicit exchange of neighbor information. The performance of the proposed protocol has been evaluated through simulation under various network densities and load conditions. It is observed that 3DRTGP significantly outperforms similar 3D geographical routing protocols in terms of end-to-end delay and miss ratio.