An interference-aware 5.8GHz wake-up radio for ETCS

Wake-up radios have been a popular transceiver architecture in recent years for battery-powered applications such as wireless body area networks (WBANs) [1], wireless sensor networks (WSNs) [2,3], and even electronic toll collection systems (ETCS) [4]. The most important consideration in implementing a wake-up receiver (WuRX) is low power dissipation while maximizing sensitivity. Because of this requirement of very low power, WuRX are usually designed by a simple RF envelope detector (RFED) consisting of Schottky diodes [1,3] or MOSFETs in the weak inversion region [2] without active filtering or amplification of the input signal. Therefore, the performance of the RFED itself is critical for attaining good sensitivity of the WuRX. Moreover, the poor filtering of the input signal renders the WuRX vulnerable to interferers from nearby terminals with high transmit power such as mobile phones and WiFi devices, and this can result in false wake-ups [1]. Although the RFED has very low power, a false wake-up will increase the power consumption of the wake-up radio as it will enable the power-hungry main transceiver.