This document proposes using low-power wireless edge devices to extend the coverage area of a single RFID reader without requiring additional costly readers. The edge devices cooperate with the RFID reader using ZigBee to read RFID tags from an increased area. Experiments showed each edge device could increase the coverage area by about 70% while lasting from 1.5 months to over 4 years depending on how often tags were accessed.

1. RFID RANGE EXTENSIONS WITH LOW-POWER
WIRELESS EDGE DEVICES
ABSTRACT:
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.