On throughput efficiency of geographic opportunistic routing in multihop wireless networks

Geographic opportunistic routing (GOR) is a new routing concept in multihop wireless networks. In stead of picking one node to forward a packet to, GOR forwards a packet to a set of candidate nodes and one node is selected dynam-ically as the actual forwarder based on the instantaneous wireless channel condition and node position and availabil-ity at the time of transmission. GOR takes advantages of the spatial diversity and broadcast nature of wireless com-munications and is an efficient mechanism to combat the unreliable links. The existing GOR schemes typically in-volve as many as available next-hop neighbors into the local opportunistic forwarding, and give the nodes closer to the destination higher relay priorities. In this paper, we focus on realizing GOR’s potential in maximizing throughput. We start with an insightful analysis of various factors and their impact on the throughput of GOR, and propose a local met-ric named expected one-hop throughput (EOT) to balance the tradeoff between the benefit (i.e., packet advancement and transmission reliability) and the cost (i.e., medium time delay). We identify an upper bound of EOT and proof its concavity. Based on the EOT, we also propose a local can-didate selection and prioritization algorithm. Simulation re-sults validate our analysis and show that the metric EOT leads to both higher one-hop and path throughput than the corresponding pure GOR and geographic routing