Cross-layer Wireless Sensor Network Radio Power Management

With the progression of computer networks extending boundaries and joining distant locations, wireless sensor networks (WSNs) emerge as the new frontier in developing opportunities to collect and process data from remote locations. WSNs rely on hardware simplicity to make sensor field deployments both affordable and long-lasting without maintenance support. WSN designers strive to extend network lifetimes while meeting application-specific throughput and latency requirements. Effective power management places sensor nodes into one of the available energy-saving modes based upon the sleep period duration and the current state of the radio. The newest generation of sensor platform radios with a 250 kbps data rate does not provide adequate time to completely power off the radio during overheard 128-byte constrained IEEE 802.15.4 transmissions. This paper proposes a new radio power management (RPM) algorithm which optimizes radio sleep capabilities by transitioning nodes to intermediate power level states. Additionally, the experimental work characterizes the radio power levels, state transition times, and state transition energy costs of an IEEE 802.15.4 compliant sensor platform for improved accuracy in simulating WSN energy consumption.