A Multi-Bit Identification Protocol for RFID Tag Reading

Fast identification for large number of tags is required in many RFID applications. To improve the identification efficiency, current tag reading protocols try to schedule the identification process with fewer collisions, since the reader cannot identify the transmission tag IDs when multibit collision happens. This paper proposes a novel tag reading protocol called the multibit identification (MBI) protocol, the reader of which can identify certain length of transmission ID-strings simultaneously by making full use of the collided bits. The basic idea of MBI is to identify the reader's receiving sequence multibit by multibit. When no collision happens in current identification unit, the reader identifies the corresponding transmission ID-string directly. When there is a single collided bit, the reader deduces the transmission ID-strings by splitting the collided bit into binary-0 and binary-1. Otherwise, a special slot called the M-slot will be activated, where the collided ID-strings of the previous slot are grouped according to a special grouping scheme and corresponding responses are made, so that the reader can deduce these ID-strings according to their collided bits. Compared with traditional tag reading protocols such as QT, JDS, and NEAA, simulation results show that MBI protocol can promise higher identification efficiency and smaller communication overhead.