Time-efficiency-oriented missing-tag identification protocols for large-scale RFID systems

One fundamental and significant issue for large-scale radio frequency identification (RFID) systems is to promptly identify the missing events of passive tags. To this end, this letter proposes two novel protocols, Tag Retardation-based Compact Protocol (TRCP) and Probabilistic Prediction-based Protocol (P³), which address the missing-tag identification problem in a more time-efficient way than existing work. TRCP conducts tag retardation to alleviate tag collisions and achieve compact tag transmissions. Due to the fact that it is unnecessary to individually identify the tags that are likely to be missing simultaneously, we design P³, which leverages tag missing probability to avert needless tag retardation to further ameliorate TRCP. Simulation results validate the superiority of both TRCP and P³ to state-of-the-art studies in terms of time efficiency.