A new opportunistic routing scheme in low duty-cycle WSNs for monitoring infrequent events

In this paper, we address opportunistic routing in low-duty cycle wireless sensor networks. Such a design must take an opportunistic approach in order to cope with the unpredictable appearance of wireless links. In fact, topology-based routing approaches are ineffective in this context. Our main objective is to maximize the network lifespan while guaranteeing i) the routing of packets to the sink and ii) acceptable end-to-end delays. We propose a new geographical opportunistic cross-layer scheme based on an asynchronous sender-oriented MAC protocol. The proposal sets the priority of selecting the next hop, among all potential candidates, according to its closeness to the sink. The next hop is elected through a selection process based on signalling bursts. The performance evaluation of our proposal is carried out both by an analytical model and simulations. The approach is evaluated in terms of i) probability of packet delivery to the sink, ii) number of hops per path and iii) end-to-end packet delay from the source to the sink.