Anti-Collision Phase Extraction in RFID Systems

With the widespread use of radio frequency identification (RFID) in the Internet of things (IoTs), RFID is becoming increasingly important. As RFID tag phase-based positioning is more accurate than signal strength-based positioning, phase extraction is indispensable for RFID-based high-precision positioning systems. In the situation of tag collision, we propose a phase extraction approach based on the electronic product code (EPC) signal segment rather than 16-bit random or pseudo-random number (RN16) signal segment by evaluating the conflict handling mechanism of the ISO/IEC 18000-6c communication protocol. Experiments in both indoor and outdoor situations have demonstrated the feasibility of the proposed phase extraction method using EPC signal segments.