| With the development of Radio Frequency Identification(RFID)technology-one of the core application technologies for the Internet of Things,the research on RFID system has attracted much attention.In the practical application of RFID system,in order to read quickly and without missing the identification tags,it is common to deploy multiple readers to read the information of the tags within the reading range of the system.In the RFID system,the reading range of multiple readers will overlap,which will lead to multiple readers reading the same tag at the same time slot or the signal interference between readers,that is,the reader collision occurs.Therefore,the information of tags cannot be read.This paper briefly discusses the research status of anti-collision algorithms for reader at home and abroad.To solve the problems existing in reader anti-collision algorithms,two RFID multi-reader channel resources allocation algorithms are proposed innovatively.The innovations and research contents of this paper mainly include the following three aspects:1.Based on the analysis of channel model characteristics in RFID system with multi-tag and multi-reader,the specific multi-reader channel resources allocation problem is modeled as a Restless Multi-Armed Bandit(RMAB)model and an auction bidding model respectively.Theoretically,it is feasible to use the Whittle index algorithm to solve the specific RMAB model and the auction mechanism to solve the specific auction bidding model.2.A multi-reader channel resources allocation algorithm based on Whittle index is proposed for the RMAB model established in the above content 1.The algorithm calculates the Whittle index value for each channel based on its current trust value.The tags select the one with the largest index value as a possible sensing and accessing channel.Then,the trust value of the channels is dynamically updated based on the feedback information of the success or failure for data transmission.For the collisions that may occur between tags during channel allocation,the method of reselecting and accessing after waiting for a certain time slots can solve it.Compared with DiCa algorithm and-Gentle algorithm,the simulation results show that the system throughput of Whittle index algorithm increased by 53.26%and 18.86%respectively,the total time slots required for tags identification process decreased by 33.86%and 16.13%respectively.It can be seen that in the channel resources allocation process of RFID multi-tag and multi-reader system,the Whittle index algorithm is superior to the typical DiCa algorithm and Gentle algorithm in terms of system throughput and the total time slots required for tags identification process.3.A multi-reader channel resources allocation algorithm based on auction mechanism is proposed for the auction bidding model established in the above content 1.The multi-bid auction mechanism is introduced in the algorithm,and the bidding value is given based on the current trust value and the transmission rate of the channel.The tags select the one with the highest bidding value as a possible sensing and accessing channel.Then,the trust value of the channels is dynamically updated to prepare for the next auction based on the feedback information of the success or failure for data transmission.For the collisions that may occur between tags during channel allocation,the method of reselecting and accessing after waiting for a certain auction rounds can solve it.Compared with DiCa algorithm and Gentle algorithm,the simulation results show that the system throughput of the multi-bid auction mechanism increased by 50.38%and 17.58%respectively,the total time slots required for tags identification process decreased by 32.58%and 14.52%respectively.It can be seen that in the channel resources allocation process of RFID multi-tag and multi-reader system,the multi-bid auction mechanism is superior to the typical DiCa algorithm and Gentle algorithm in terms of system throughput and the total time slots required for tags identification process. |
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