Date Added: Oct 2009
This paper presents an efficient mechanism to achieve significant energy savings in heterogeneous wireless sensor networks such as HPWREN. Environmental sensors are typically located in remote and hard-to-reach locations far from the main high-bandwidth data links. Therefore the sensed data needs to be routed through multiple hops before reaching the backbone. The routing is done by battery-powered nodes using license free radios such as 802.11. In this context, minimizing energy consumption is critical to maintaining operational data links. The authors propose a distributed low-power scheduling algorithm that limits the number of active nodes and allows a large portion of nodes to sleep. The algorithm works in a completely distributed manner, requiring handshaking only when a node enters and exits the network.