A Improved Anti-Collision Algorithm in RFID System of Internet of Things

The anti-collision problem is one of the difficulties of RFID in IOT. In the IOT system, there may be more than one tag in the working range of one reader. When the reader start these tags, all of them will transmit data to the reader at the same time, it will cause the reader can not read the data from the tags correctly. Use the anti-collision technology the IOT can prevent multiple tags simultaneously transmit data which causes collision. The current anti-collision algorithms are mainly Slotted ALOHA method and Binary Search method. The basic ALOHA algorithm has high current efficiency, but with the increase of the tags, the efficiency of the system will decrease greatly. This paper presented an improved ALOHA algorithm. In the proposed algorithm, the number of tags was estimated dynamically, with which a suitable size of window can be chosen to get higher system efficiency. At the same time, grouping strategy was introduced into the algorithm. The simulation results have shown that the proposed algorithm has higher system efficiency and lower working time.