Tunable Time Resolution: An Energy Saving Mechanism for Wireless Sensor Networks

We present Tunable Time Resolution (TTR), a novel energy-conserving technique, to reduce the power consumption of Micro Controller Unit (MCU) in low-duty-cycle wireless sensor networks. This power consumption is highly correlated to the time resolution of the operating system, which is decided by the frequency of Timer Interrupt Request (IRQ). Therefore, we utilize a high time resolution in active periods of sensor node to support events scheduling, and a low resolution in sleep periods to avoid energy waste. Through analyses on the optimal time resolution in different periods, Tunable Time Resolution is present to maximize the energy efficiency by dynamically adjusting and carefully switching the time resolution. TTR is implemented in Tmote-sky platform. Evaluation results show that TTR can cut down the total power consumption up to 45.5% when the duty cycle is lower than 1%.