Early collision detection and handling in cdma-based rfid systems

Abstract

A method, system and computer program product for enabling early collision detection and handling in Code Division Multiple Access (CDMA)-based radio-frequency identification (RFID) systems. A tag receives an instruction from a reader to reflect either a single encoded bit or multiple encoded bits. The tag then reflects either the single encoded bit or the multiple encoded bits to the reader. The reader decodes the received encoded bit(s) from the tag, where the decoded bit(s) are placed in a vector or matrix by the reader. The vector/matrix is then transmitted to the tag, which determines if the reflected bit(s) agree with the corresponding bit(s) in the vector/matrix thereby indicating whether the reflected bit(s) were read successfully by the reader. The tag will then enter a no reflection mode in response to a disagreement between the reflected bit(s) with the corresponding bit(s) in the vector/matrix thereby preventing collisions from occurring.