RFID cardinality estimation method for intelligent warehouse

With the rapid development of RFID technologies, RFID has been introduced into applications such as supply chain management, inventory control, sampling inspection, 3-D positioning and object tracking. Usually, the reader accesses all the tags in its interrogation region while some applications may only need to identify the tags in a specified area which is smaller than the reader's interrogation region. This paper concerns the essential problem of estimating cardinality of tags in the specified area. The key novelty of our solution builds on an estimation synopsis that can capture key counting information by moving the reader as well as a simple operation. With the help of this data structure, a BS can be obtained which only contains the target tags. By computing the number of 1 in the BS, we can easily get cardinality |E| of the tags in the specified area. We conduct extensive experiments to examine this design and the results shows that our solution achieves high efficiency. Because it not requires any modification of tags and can be implemented with only one reader and some passive RFID tags, the proposed method is easy to deploy in a practical system.