Range query with the existence of missing tags for large-scale RFID systems

This paper designs an efficient range query protocol for large-scale RFID systems that addresses the existence of unknown tags while simultaneously identifying missing tags. Range query aims to classify target tags according to the ranges specified by users. However, existing range query protocols do not consider the existence of missing tags, leading to incorrect classification results. To handle this issue, we propose a protocol called Missing Tag Identification and Range Query Scheme (MRQS), which selects singleton slots and 2-collision slots to receive range information and identify missing tags. Expected empty slots are used to filter out unknown tags. Compared with the related range query protocols, simulation results show that the proposed MRQS scheme yields accurate classification results for target tags in the presence of missing tags and unknown tags.