Abstract: As an important technical support of intelligent Internet of things, radio frequency identification (RFID) technology has been widely used in supply chain tracing and real-time monitoring. In order to improve the tracking and query efficiency of tagged objects in the RFID-based supply chain environment, it is necessary to effectively encode the temporal and spatial data of RFID objects. Considering the characteristics including big volume, the existence of the loop and frequent update of the data in RFID-based supply chains, based on the idea that infinite vectors can be inserted between a pair of vectors, an offset addition vector path coding strategy is proposed. This strategy takes spatiotemporal data nodes as coding objects and assigns a unique pair of vectors to each node by vector addition to achieve uniform coding. At the same time, an optimization strategy is proposed to solve the overflow problem caused by excessive code value, and the correctness of the optimization strategy is proved. The experimental results show that the proposed vector encoding strategy and its optimization strategy can meet the requirements of different types of tracing queries, and have the advantages of fast encoding speed, slow overflow of code value, high update efficiency and can support loop.

Key words: radio frequency identification (RFID), path coding, vector coding, tracing query, Internet of things (IoT)