MGR: a multicandidate greedy routing scheme in wireless sensor networks

Sleep and wake-up scheduling of sensor nodes is an efficient solution to prolong the network lifetime. However, existing scheduling algorithms may significantly decrease the number of active nodes so that the network may be intermittently connected. In light of this, traditional geographic routing protocols are inappropriate to obtain low latency routes due to route discovery and data forwarding latency. Recently, Lu Su et al. have proposed an ODML routing scheme that finds low latency routes in intermittently-connected sensor networks by using RREQ and RREP messages [9]. Nevertheless, ODML does not consider the latency of RREP and has a high routing overhead. This paper proposes a novel Multicandidate Greedy Routing (MGR) scheme that makes the best effort to find minimum latency routes in wireless sensor networks. In MGR, each source node sends an RREQ to a set of first wake-up forwarder candidates and selects a route with minimum estimated delivery latency based on their replies. Simulation results demonstrate that our proposed scheme performs better than the distance-based greedy forwarding and ODML in terms of delivery latency and routing overhead.