ORAS: Opportunistic Routing With Asynchronous Sleep in Wireless Sensor Networks

Opportunistic routing and asynchronous sleep are both recent techniques those change the traditional way of routing and MAC layer implementation. The existing opportunistic routing schemes, designed for increasing throughput of connection rather than saving energy, are not appropriate for Wireless Sensor Networks due to low energy efficiency caused by overhearing and scheduling. In this paper, the authors propose Opportunistic Routing with Asynchronous Sleep (ORAS), a robust integrated routing and MAC protocol that combines opportunistic routing and asynchronous sleep. ORAS makes a sender rendezvous with just enough asynchronous sleeping neighbors to ensure the packet received by a potential forwarder with a high probability.