The states and keys of the target device are used to
facilitate tag singulation, collision arbitration, security encoding, etc.
The communication primitives of ISO 18000 Part 6C standard are signi?¬?cantly different
and more complex than the ISO 18000 Part 7 standard. The complexity of the Part 6C
standard makes the design of these tags extremely time consuming and challenging
for reducing power consumption and silicon area. Dontharaju et al. [44] examines
various features of the ISO Part 6C standard and compares it with the ISO 18000 Part 7
standard for active tags for the purpose of evaluating generic interrogator=tag protocol
complexity.
An example transaction of this protocol is shown in Figure 3.30. The output shown in
this ?¬?gure is generated from a special piece of equipment housed in the University of
Pittsburgh RFID Center of Excellence called a real-time spectrum analyzer (RTSA).
The example tag uses passive RFID technology requiring the RF energy generated by the
reader to be used to power the tag, and to be used for a backscatter-based response.
Backscattering uses the re?¬‚ection of RF energy provided by an external source (in this
case the reader) to transmit information. The backscattering device (in this case the tag)
either absorbs or re?¬‚ects the energy of the incoming RF to generate low and high values in
the backscattered response.
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