Optimization Of The Anti-collision Algorithm In The RFID System With Moving Tags

Radio frequency identification is an important branch in the current recognition field. Relative to the traditional identification technology, Radio frequency identification technology has a lot of incomparable advantages, for example, non-contact identification, penetrating, and can be repeatedly erased. Due to these advantages, the RFID technology is applied in a wide range of applications and development of many fields in recent years. The RFID technology becomes a hot area of scientific research. The tag anti-collision algorithm is one of the most important issues in RFID systems. Tag anti-collision direct impact on the system tag recognition rate and speed. In the past researches of anti-collision algorithm, the electronic labels of system is always stationary, neither the tag enters the system identification area, nor label to leave the system identification area. But in real applications, the electronic labels on the goods are often to maintain a certain speed and go through the system identification area.In this paper, many research works has been done expect to solve these problems. First of all, based on the traditional ALOHA anti-collision algorithms, we research the anti-collision of RFID system on the conveyor belt model. The movement in this case is relatively simple. Mathematical formulas of tag identification rate in the RFID system and the derivation of Mathematical formulas is give, also this paper use MATLAB software for the computer simulation. Results show that when the RFID system’s frame length N and the length of conveyor belt within RFID identification region L is fixed. The system has the maximum tag identification rate when the numbers of tags n equal to the frame length N, the maximum tag identification rate is36.78%. The tag identification rate and the conveyor speed V、the number of tags on the unit length of conveyor D and the RFID system’s time slot continuous time Ts is an inverse relationship. Surprisingly, the length of the conveyor belt in the area of RFID identification area t had no effect with the tag identification rate of RFID system. But it can affect the stability of the tag identification rate.Secondly, the paper also proposes a new tags estimation method. The proposed method is based on the collision factor of RFID system. MATLAB simulation show, the estimate accuracy of the new method has greatly improved compared with the traditional estimates. Especially when the ratio of tag number and frame is large, the proposed estimate in this paper still has higher accuracy. Results of MATLAB simulation show that when the RFID system use the new tags estimation method, the recognition speed and tag identification rate of RFID system are improved.Finally, we use AT89S52and TRF7960to design the RFID Reader and give the schematic of different parts and the corresponding software program. Also we use PROTEUS software to give the simulation of these design modules on the computer.