Design and Analysis of a Novel Time- and Energy-Efficient $M$ -Ary Tree Protocol With Collision Window for Dense RFID Systems

This paper proposes a novel time- and energy-efficient identification protocol for dense radio frequency identification (RFID) systems. The protocol is designed based on a conventional <inline-formula> <tex-math notation="LaTeX">$M$ </tex-math></inline-formula>-ary collision tree, where tags involving a collision are classified into other <inline-formula> <tex-math notation="LaTeX">$M$ </tex-math></inline-formula> subtrees. We additionally incorporate a newly designed transmission mechanism, by which each tag only responds to the reader by a small number of bits for a collision detection. The mechanism relies on a collision window supported by tag cardinality estimation, and the Manchester encoding, which is widely used for RFID systems. Thanks to the mechanism, the number of bits transmitted by tags can be significantly reduced, which improves the overall system performance in terms of both time and energy consumption. Theoretical analysis and computer simulation are performed to validate the correctness of the mechanism. The obtained results are compared with those of conventional protocols, which confirm the effectiveness of the proposed protocol.