Energy consumption reduction methods of geographic routing protocols with out-of-date location information in mobile ad hoc networks

Geographic routing protocols route packets in a hop-by-hop manner, where a node selects a relay node to forward packets among the (1-hop) neighboring nodes based on the obtained (geographic) location information of the neighboring nodes. To employ geographic routing protocols, two neighboring nodes need to exchange the location information with each other periodically. In a mobile ad hoc network, however, a packet transmitted between two neighboring nodes may be lost due to the out-of-date location information, resulting in demanding extra energy to retransmit the packet. In this paper, by considering the out-of-date neighboring location information, we propose two methods capable of augmenting geographic routing protocols to reduce energy consumption in mobile ad hoc networks. The first one considers a tradeoff between the progress distance and the energy consumption when selecting a relay node. The second one puts emphasis only on the energy consumption when selecting a relay node, and it consumes minimum energy to route a packet between a source-destination pair in the continuous domain. Simulations show that geographic routing protocols augmented with our methods can significantly reduce the energy consumption while preserving the high packet delivery rate.