Purpose Radio Frequency Identification (RFID) tag cardinality estimation is vital for dynamic asset management, but existing methods struggle with signal interference in large-scale deployments and suffer from estimation accuracy degradation due to distance differences between tags and reader. This study aims to propose a group-based distance-aware protocol that optimizes reader configuration through tag grouping and real-time distance measurement, ensuring accuracy and efficiency in tag cardinality estimation. Design/methodology/approach This study proposes a two-phase RFID tag cardinality estimation protocol. In the first phase, tags are grouped based on electronic product code (EPC) coding characteristics, and their distances are estimated using Received Signal Strength Indicator (RSSI) values to dynamically optimize reader configuration. In the second phase, communication signals are collected via a Universal Software Radio Peripheral (USRP), and advanced signal processing methods are applied to achieve precise tag cardinality estimation. Findings Under standard testing, the protocol reduces average error rate by 7.61% at 2.5 m while improving time efficiency by 31.8% versus baseline methods. Originality/value The protocol innovatively proposes a tag grouping strategy based on EPC coding characteristics, and dynamically adjusts the reader parameter configurations for each group in real-time using RSSI ranging technology, effectively adapting to signal attenuation and interference issues caused by distance variations between tags and reader. In addition, by leveraging the high-precision signal acquisition capability of USRP devices, it achieves accurate measurement of tag cardinality estimation.
Zhang et al. (2026) studied this question.