Digital Baseband Modulation Termination in RFID Tags for a Streamlined Collision Resolution

Abstract

Radio Frequency Identification (RFID) technology has attracted much attention due to its variety of applications, e.g., inventory control and object tracking. Tag identification protocols are essential in such applications. However, in such protocols, significant time and power are consumed on inevitable simultaneous tag replies (collisions) because tags can't sense the media to organize their replies to the reader. In this paper, novel reader-tag interaction method is proposed in which low-complexity Digital Baseband Modulation Termination (DBMT) circuit is added to RFID tags to enhance collision resolution efficiency in conjunction with Streamlined Collision Resolution (SCR) scheme. The reader, in the proposed SCR, cuts off or reduces the power of its continuous wave signal for specific periods if corrupted data is detected. On the other hand, DBMT circuit at the tag measures the time of the reader signal cutoff, which in turn, allows the tag to interpret different cutoff periods into commands. SCR scheme is applied to ALOHA- and Tree-based protocols with varying numbers of tags to evaluate the performance under low and high collision probabilities. SCR provides a significant enhancement to both types of protocols with robust synchronization within collision slots. This novel reader-tag interaction method provides a new venue for revisiting tag identification and counting protocols.