Location-aware anti-collision protocol for energy efficient passive RFID system

Radio Frequency IDentification (RFID) system has been wildly used in recent ten years. A Handhold reader and some passive tags compose an efficient system for retail scenarios, such as storage management and item inventory. However, the heavily energy consumption of the reader battery, which due to the frequent tag collisions, is a main limitation for such a RFID system in large scale item-level scenario. To avoid the collisions, Dynamic Frame Slotted ALOHA anti-collision algorithms (DFSA) are popularly being used. But unreliable tag number estimation and non-optimized frame size selection may lead to more energy consumption. In this paper, we propose a novel tag population estimation and frame length selection method based on tag location-aware scheme to optimize the DFSA tag anti-collision algorithm. In our method, the handhold reader firstly collects the tags´ location information and divides them into different clusters based on their distance from the reader. Then by estimating the tag population for each cluster, the reader utilizes this value to achieve an optimum frame size and automatically adjusting the transmission power to scan the tags in corresponding tag cluster. We also give a quantitative energy consumption model for the passive RFID system. According to the simulation results, the passive RFID system throughput and energy efficiency can be highly increased by using our scheme.