Energy efficient protocols for low duty cycle wireless microsensor networks

Emerging distributed wireless microsensor networks will enable the reliable and fault tolerant monitoring of the environment. Such microsensors are required to operate for years from a small energy source, while maintaining reliable communication link to the basestation. The design of energy-aware communication protocols can have a dramatic impact on the network lifetime for such applications. A detailed communication energy model, obtained from measurements, is introduced that incorporates the non-ideal behavior of the physical layer electronics. This includes the start-up energy cost of the RF tranceiver, which dominates energy dissipation for short packet sizes. Using this model, various communication layer protocols are explored for asymmetrical sensor networks such as machine monitoring. The paper also proposes the use of a variable bandwidth allocation scheme, that exploits spatial distribution of sensors.