An Adaptive Power Control Algorithm in RFID Systems

Nowadays, RFID technology has been widely spread in various fields. However, the situation of the reader-to-reader collision, caused by movements of readers, is becoming more and more prominent. To solve this problem, this paper proposes an adaptive power control algorithm based on the SNR-measurements method, which uses the Kalman filtering algorithm to estimate the wireless channel characteristic at first, and then adjusts the transmission power of the reader variously according to both channel estimated results and SNR histories, which determines the step size. As shown in simulation results, the algorithm proposed could avoid reader-collision effectively. The algorithm not only provides improvements on real-time ability as well as reliability, but also improves the throughput and precision of identifying tags.