DTGR: Disruption-Tolerant Geographic Routing for Wireless Ad Hoc Networks

In wireless ad hoc networks, temporary link disruptions can frequently occur due to the presence of obstacles, node mobility, and so on. These disruptions can result in a node’s incorrect perception of its neighbor set when the neighbor set is constructed via beacon sampling (e.g., beacon collisions may result in the removal of a node j from the neighbor set of a node i, although j is within the transmission range of i). Such a behavior can adversely affect the performance of position-based routing algorithms as it may lead to inefficient routing or packet dropping. To address this, the authors propose a scheme that allows node i to associate each of its neighbor j with a reachability value that is a measure of the stability of the link between i and j. They then apply their scheme to greedy perimeter stateless routing (GPSR) and design two new routing algorithms: disruption-tolerant geographic routing—simple forwarding (DTGR-SF) and disruption-tolerant geographic routing—waiting before forwarding (DTGR-WF), in which nodes use reachability values to make forwarding decisions. The authors compare the performances of DTGR-SF and DTGR-WF with that of GPSR in various simulation settings. Their simulation results show that proposed algorithms perform better in settings where disruptions are present. In networks with few occurrences of disruptions, their schemes achieve the same high performance as that of GPSR.