ALOHA Tag Anti-collision Algorithm Based On Power Control

Radio Frequency Identificaiton (RFID) is one of the automatic identification technologies, which utilizes the coupling of the magnetic field to realized wireless communication and automatic identification. RFID technology has many advantages compared with barcode, such as long reading distance, strong penetrating object, high efficiency, large data storage capacity and so on. RFID technology has a wide range of application in many fields. Therefore, RFID technology becomes the focus of researchers. Although RFID technology has many advantages, and in many areas has good prospects, there are still many problems to be solved. Tag collision is one of them.Paper firstly introduces the composition and the working principle of radio frequency identification system. It analyzes the performance of typical tag anti-collision algorithms in detail and compares them. The innovation of anti-collision algorithms based on ALOHA are proposed. First, anti-collision algorithm model based on power-control has been introduced. Second, hash coding mechanism and collision detection mechanism have been introduced. The Stepped Power-Control ALOHA (SPCA) divided the identification region of the reader into several fixed sub regions. The identification radius of each sub region is increased by fixed step length. The Adaptive Power-Control ALOHA (APCA) divided the identification region of the reader into sub regions according to the optimization grouping scheme dynamically. The APCA algorithm can control the number of tags in the sub region, regardless of the uniform distribution of the tags or the non uniform distribution, thus the performance of the APCA algorithm is always maintained at a high level. In anti-collision algorithm based on power-control and collision detection, the UUID of tags will do hash coding and tags will be mapped to the corresponding slots in this algorithm, improving the utilization rate of slots. Then, collision detection mechanism allows only non-collision tags to communicate with the reader, thereby greatly reduces the ineffective communication process. Finally, the power-control mechanism to identify the tags by region significantly reduces the tag collision and saves the energy consumption of communication.Finally, we use MATLAB to simulate the proposed algorithms. We analyze and compare the results of the new algorithms and the existing algorithms. It can be seen from the analysis of simulation results that the performance of the algorithms have improved significantly compared with the existing anti-collision algorithms. The anti-collision algorithms can satisfy the RFID system requirement, which improve the stability of system.