DTGR: Disruption tolerant geographic routing for wireless ad hoc networks

In wireless ad hoc networks, temporary link disruptions can frequently occur due to presence of obstacles, node mobility, etc. 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, we propose a scheme that allows each node to associate its neighbors with a reachability value that is a measure of the stability of the link between the node and its neighbor. We then 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 utilize reachability values to make forwarding decisions. We compare the performance of DTGR-SF and DTGR-WF with that of Greedy Perimeter Stateless Routing (GPSR) in various simulation settings. Our simulation results show that our proposed algorithms perform better in settings where disruptions are present. In networks with few disruptions, our schemes achieve the same high performance as that of GPSR.