WUR-TS: Semi-Passive Wake-Up Radio Receiver Based Time Synchronization Method for Energy Harvesting Wireless Networks
Yu Dong Luo, Lina Pu · IEEE Transactions on Mobile Computing · 2021
In this paper, a semi-passive wake-up radio receiver based time synchronization (WUR-TS) method is developed for energy harvesting wireless networks. In WUR-TS, energy harvesting nodes (EHNs) do not exchange any timing information, but only receive the wake-up signal broadcast periodically by the central node to synchronize time throughout the network. Based on the experimental data, a model is developed to accurately estimate the arrival time of each wake-up signal. By using this model, the EHN can calculate its clock drift in complex radio environments. We have implemented WUR-TS with a minimum number of commercial components. According to the experimental results, WUR-TS can achieve a synchronization accuracy of 3$\mu$s when the power supply voltage is 2.8 V and the received wake-up signal strength is higher than$-$33 dBm. WUR-TS is an ultra-low-power synchronization method. If no wake-up signal is detected, the power consumption of each EHN is 3.2$\mu$W. If the wake-up signal is detected, the EHN consumes only 3.6$\mu$J of energy to complete time synchronization.