A High-efficiency RFID Tag Search Protocol Based On Historical Information

Radio Frequency(RFID)is one of the core technologies in the IOT.It is widely used in warehouse management.In a warehouse,RFID readers need to search some tags.Research for RFID tag search solve a problem: Given a group of tags,called wanted tags,tag search can determine which of them currently present in the system.Traditional solution is identifying all tags in the system,and then compare with wanted tags.This method is inefficient when the number of tags is large,and the existing tag search protocol only use the single slot to judge the existence of the tag,while the collision information id directly ignored,resulting in a waste of slot information.It has very important application significance to study how to improve the efficiency of tag search.In view of the above situation,this paper combines database tag information,makes full use of the characteristics that time slot information could determine tags whether exist or not,and study the tag search problem in RFID technology.The main contributions are as follows:At first,a Tag Search Protocol(THIR)based on historical information reasoning is designed to search tags faster.The reader establishes an indicator table based on the ID information of the known database tag,which is used to predict the tag status of each time slot,and collects the actual reply information of system tags.In each slot,the reader compares the predicted state and the actual state of the slot,to reason the existence state of the tag in the slot,The slot information that cannot be directly reasoned,called historical information,will be saved in the historical information base with a mathematical inequality form.The historical information will involve in a further analysis for the tags' state when the slot is over.The simulation experiment shows that the THIR protocol has higher time efficiency than the existing three protocols.Then,An improved tag search protocol(E-THIR)with multiple eliminating based on the THIR protocol is designed to eliminate the impact of useless information.E-THIR includes two eliminating methods,which can effectively exclude some irrelevant tag information.The first is a slot division eliminating method,which divides the indicator table into different time slots.In eliminating slot,reader can broadcast instructions to directly eliminate the irrelevant tags in the time slot,therebyreducing the time consumption;The second is filtering vector eliminating method.The reader establishes a filter vector according to the database tags,and sends it to the system tags.System tags determines whether it meets the eliminating condition after calculation,and if it is,it will enter a silent state.According to the results of the simulation experiment,the E-THIR protocol has higher time efficiency than the THIR protocol,and it is suitable for more scenarios.