On Using Sampling Bloom Filter for Unknown Tag Identification in Large-Scale RFID Systems

Radio Frequency Identification (RFID) is one of the key technologies for Internet of things. In RFID systems, the tags without registering in advance are called unknown tags, which usually appear in the scenarios, where the tag-attached objects are moved into or misplaced in the reader's interrogating area. Consequently, unknown tag identification is significant for RFID-based applications, which is the concentration of this paper. We first propose a basic efficient unknown tag identification protocol based on sampling Bloom filter called UTI-SBF, which consists of known tag deactivation phase and unknown tag identification phase. The idea behind the UTI-SBF protocol is to deactivate the known tags to counteract their interference on the unknown tag identification. Then, we propose an enhanced protocol called EUTI-SBF, which eliminates the non-homogeneous slots based on the UTI-SBF protocol to improve the time efficiency. The parameters of the two protocols are theoretically analyzed to maximize the efficiency. We conduct extensive simulations to evaluate the proposed UTI-SBF and EUTI-SBF protocols and the simulation results illustrate that the UTI-SBF and EUTI-SBF protocols outperform the BUIP protocol. In particular, the EUTI-SBF protocol only consumes about 70% of deactivation time compared with the BUIP protocol in the known tag deactivation phase.