An Efficient Protocol of Queries for Large and Small Categories in RFID Systems

One of the most important problems for categorized radio-frequency identification systems is to find large categories and small categories. In this article, we propose a protocol that can find the large categories and the small categories quickly. The protocol uses multiple hash pairs to allocate as many tag categories as possible to distinct slots to estimate the sizes of the tag categories. Specifically, we optimize the parameters by minimizing the execution time of the protocol. Extensive simulation results demonstrate that the proposed protocol is superior to the state-of-the-art protocols. Particularly, when the length of single-one-geometric (SOG) string is 32 b, it reduces nearly 24% of the required execution time compared with the Top-k protocol and reduces 77% of the required execution time compared with the ART protocol.