A Delay-Based Wake-Up Receiver for Wireless Sensor Networks

One of the main limitations in the design of wireless sensor networks is the optimization of the power management. A possible solution is the implementation of wake-up receivers (WuRxs), which activate the sensor nodes from deep sleep only when communication is required. The majority of WuRxs presents complex architectures based on amplifiers, comparators and demodulators. In this work we propose a new low power WuRx concept based on complementary circuitry. The proposed WuRx receives and measures the width of the input signal with different predefined signal pulse widths using delay lines. If the received signal resembles the correct wake-up call, i.e. it has the right duty cycles, it sequentially activates the WuRx and wakes up the sensor node. A possible circuit implementation in TSMC-180nm CMOS process is reported. The simulation results confirm the proposed delay comparison mechanism. The WuRx consumes 35µA when receiving a 12ms selective wake-up call signal, and 337nA when in the idle mode.