Anti-collision methods for chipless RFID systems

Radio Frequency Identification enables automatic identification of objects with least human involvement. Chipless RFID is the low-cost alternative of conventional chip based system. In many application multiple tags collide with each other making the reading and identification challenging for the reader. It also degrades the reading reliability of the system. Therefore identifying tag-tag collision and simultaneous reading of multiple tag is significantly important in any RFID system. Chipless RFID is a new domain in RFID family and like other conventional RFID system it also suffers from tag-tag collision problem. In this paper a review on tag-tag collision for chipless RFID systems based on available literature has been presented. Finally some new methods have been proposed for collision avoidance in chipless RFID systems.