Impact of Hidden Nodes on Wake-Up Signaling Based on Frame Length Modulation for Energy-Efficient WLAN

This paper investigates the impact of hidden nodes on wake-up signaling employed to realize energy-efficient wireless LAN (WLAN). The considered wake-up mechanism is based on frame length modulation which exploits WLAN frames as a wake-up signal: a station with communications demands transmits a series of WLAN frames with length corresponding to wake-up ID of the target receiver in a sleep mode. The wake-up receiver attached to the target of wake-up signal only performs a limited signal processing to detect each frame length, which consumes little amount of energy. Since WLAN frames are transmitted with carrier sense multiple access (CSMA) protocol, the wake-up signaling with frame length modulation is vulnerable to hidden node problem. In this paper, we theoretically investigate the impact of hidden nodes on the frame length detection. We also evaluate the wake-up failure probability when the length of frame transmitted by hidden nodes is decided according to a practical trace data of WLAN frames. Our analysis and obtained results give us the insight on how to alleviate the negative impact of hidden nodes on wake-up signaling.