Efficient sensor-equipped tags information collection protocol in large-scale RFID systems

Sensor-equipped RFID tag provides both ID and real-time information about an item's status or environment. Efficiently collecting information from sensor-equipped tags, also known as target tags, is crucial for effective inventory management and environmental monitoring in warehouses. However, in a multi-reader scenario, each reader doesn't know what the IDs of the tags in the interrogation region are. Attempting to access all target tags in the system results in a significant number of empty time slots, reducing the efficiency of information collection. To overcome this challenge, we propose the Bloom-Perfect hashing based information collection (BPIC) protocol. It constructs a Bloom filter for the reader using tag response information, excluding tags outside the reader's interrogation region. Then several allocation vectors are broadcasted by the reader to determine the reply order for local target tags, and minimal perfect hashing filtering (MPHF) and polling operations are used to exclude all non-target tags, ensuring conflict-free information collection from target tags. The experimental results demonstrate that the efficiency of information collection in the BPIC protocol is better than that of the existing LocP and E-TIC protocols.