Passive RFID Tag Anticollision Algorithm for Capture Effect

Capture effect is very common in passive radio frequency identification systems. Even though multiple tags transmit their signals to a reader simultaneously, one of the tags will be successfully identified due to capture effect. However, capture effect may hide some tags. Many existing algorithms that assume no capture effect will miss the hidden tags. In this paper, we extend an existing algorithm to the capture effect environment and propose a novel tag anti-collision algorithm to enhance the efficiency of tag identification. The proposed algorithm adopts an allocation strategy to reduce collision between the hidden tags by capture effect and the other tags. The strategy lets the collided tags resolved in a current cycle immediately. On the other hand, the hidden tags will enter the next cycle. Thus, the resolved tags will not collide with the hidden tags in the next cycle, and the collision will be reduced. The experiment results show that the proposed protocol's identification efficiency outperforms other existing protocols when the occurrence probability of capture effect varies from 0.1 to 0.6.