RFID range extension with low-power wireless edge devices

Coverage area is an important performance metric for RFID systems, especially those used for inventory management. As such, there are a range of methods being developed to try to increase the coverage area of RFID systems without requiring additional costly and power hungry RFID readers. Most existing approaches to increase coverage employ RFID readers with multiple antennas, but this creates problems in deployment and in the timing of the RFID tag reads from the different antennas. In this paper, we propose a different approach to extend the coverage area of a single reader, using a ZigBee-based, battery-operated device we call an edge device to cooperate with the RFID reader on reading the RFID tags. The edge device is also compatible with existing RFID range extension methods for additional increase in coverage. We implement an edge device hardware platform and evaluate the performance of the system in terms of coverage extension, and we provide estimates of the lifetime achievable for different tag access scenarios. Our experiments show that each low cost, easily deployable edge device can increase the coverage area by about 70 %, and that they last for about 1.5 months if the tags are accessed twice an hour to upwards of 4 years if they are accessed once a day, as is sufficient for many inventory management applications.