Improved geographic routing in sensor networks subjected to localization errors

Abstract

Geographic routing strategies used in wireless communication networks require that each transmitting node is aware of its location, the locations of its neighbors, and the destination. With this information, the message is routed by choosing intermediate nodes, or relays, which allow the destination to be reached with the maximum possible transmitted information rate and with minimum delay. However, this strategy needs to take into account the uncertainties of the relays locations in order to avoid an important performance degradation of the link, or even a routing failure. Taking into account the presence of uncertainties in the relays locations, each possible geographic routing strategy is able to recognize a subset of nodes that can be candidates for relays. Furthermore, the transmission range between nodes not only depends on the distance between them, but also the communication channel fading. Based on the effect that these uncertainties have on the link channel capacity, a minimization of a cost function is proposed to decide the next hop relay, which optimizes, in mean, the maximum rate of information transmitted with the minimum number of hops. Using the location statistics, this optimal strategy is applied for both one-hop decisions and two-hops decisions. Working expressions for on-line fast calculations are provided and used for results illustrations.