RFID and Sensor Networks: Architectures, Protocols, Security

EPC Gen-2 Standard for RFID � 123
The attenuation of the RF signals by the other items reduces the range at which
readers and tags can communicate. This limits the size of the pallet to ensure that all tags
can be read to take an accurate inventory. Changing the physical layer properties of the
protocol is not wise as this could obsolete existing products based on Gen-2.
Using the right mix of commands to inventory a group of tags is important. Although
simply trying to inventory all tags within a range at the same time will work, the benefits
of the truncate and mask features of the Select command are not used. Properly using
the Select command is important as time is added to define the subset of tags that
will participate in the inventory round. Accurately predicting the type of pallet being
inventoried is important to minimizing the time to take the inventory. Also, selecting
the right mix of inventory commands is important to minimizing the time to read all
the EPC numbers. Research into developing models or policies for both areas is needed.
References
1. EPC TM radio-frequency identify protocols class-1 generation-2 UHF RFID protocol
for communications at 860 MHz–960 MHz version 1.1.0, EPCglobal Inc., 2005.
2. EPCglobal tag data standards version 1.3.1, EPCglobal Inc., 2007.