Design and analysis of a multi-candidate selection scheme for greedy routing 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 networkmay be intermittently connected. In such networks, traditional geographic routing protocols are inappropriate to obtain low latency routes due to route discovery and data forwarding latency. In this paper, we propose a novelmulti-candidate selection (MCS) scheme for greedy routing that makes the best effort to findminimum latency routes in the sensor networks. InMCS, each source node sends an RREQ to a list of first wake-up forwarder candidates and selects a route withminimum estimated delivery latency based on their replies. The route foundbyMCSmaybe longer than that of distance-based greedy forwarding (DGF) (Finn, 1987). Hence, we introduce a latency-adaptive distance-based multi-candidate selection scheme for greedy forwarding to find routeswith a small number of hops and acceptable delivery latency. Probabilistic analysis and simulation results demonstrate that MCS increases the routing performance significantly compared with DGF and ODML (Su et al., 2008) in terms of delivery latency. & 2010 Elsevier Ltd. All rights reserved.