Research on RFID Anti-Collision Algorithm of Slot Responding in Real-Time and Co-Processing

Although RFID( Radio Frequency Identification,RFID) is capable of identifying multiple tags synchronously,the tag collision occurs inevitably when a large number of tags respond in the induction area of reader simultaneously,which seriously influences the throughput of RFID system because signal aliasing arises from tags occupying the channel randomly. In order to further improve the throughput of RFID system,this paper proposes a new anti-collision algorithm with adjusting inventory cycle by the preset difference threshold,the slot checking forward,the slot predicting backward and the slot binary splitting,which are coordinately combined to deal with the response of the current slot and the next slot when algorithm complexity and hardware are not added in tags. In the algorithm,the preset difference threshold can prevent reader from floating point computation. Meanwhile,the methods of slot checking forward and predicting backward are joined together to judge the response of the current slot and the next slot in advance,which can skip the current idle slot and the next idle slot,and split the tags responding in the current collision slot and the next collision slot in real time. In the following three simulation experiments,ways of inventory cycle adjustment,methods of slot splitting,the identification delay and throughput are compared respectively. The results indicate that the improved anti-collision algorithm can raise the computation efficiency of reader,effectively reduce the time of channel occupied by invalid slots,and as a result,the throughput of RFID system can reach more than 52%.