Sift: A MAC Protocol for Event-Driven Wireless Sensor Networks

Nodes in sensor networks often encounter spatially-correlated contention, where multiple nodes in the same neighborhood all sense an event they need to transmit information about. Furthermore, in many sensor network applications, it is sufficient if a subset of the nodes that observe the same event report it. We show that traditional carrier-sense multiple access (CSMA) protocols like 802.11 do not handle the first constraint adequately, and do not take advantage of the second property, leading to degraded latency and throughput as the network scales in size. We present Sift, a medium access protocol for wireless sensor networks designed with the above observations in mind. Sift is a randomized CSMA protocol, but unlike previous protocols, does not use a time-varying contention window from which a node randomly picks a transmission slot. Rather, to reduce the latency for the delivery of event reports, Sift uses a fixed-size contention window and a carefully-chosen, non-uniform probabi...

• Type: Conference
• Year: 2006
• Where: EWSN
• Authors: Kyle Jamieson, Hari Balakrishnan, Y. C. Tay
• Keywords: EWSN 2006, Fixed-size Contention Window, Sensor Networks, Wireless Networks, Wireless Sensor Networks