Detection and Recovery of RFID Harmonic Signal for Wi-Fi Interference

In the realm of the Internet of things (IoT), radio frequency identification (RFID) technology is essential for linking physical objects to digital data. The introduction of harmonic technology has expanded RFID's applications by improving sensitivity and enabling communication with wireless fidelity (Wi-Fi) networks. However, this trend faces challenges, notably interference from strong Wi-Fi signals, which impacts RFID-based sensing systems. This paper proposes the WiFID (Wi-Fi and RFID) algorithm, which enables Wi-Fi devices to sense weak RFID harmonic signals. Adaptive subcarrier deallocation minimally reduces Wi-Fi throughput while effectively limiting interference with RFID harmonic sensing. Experimental validation on the universal software radio peripheral (USRP) platform demonstrates that WiFID successfully detects 90% of RFID harmonics at −30 dBm, with only a minimal 4% decrease in Wi-Fi throughput.