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•RFID White Paper: UHF Gen 2 Interoperability

By Impinj, Inc.

RFID hardware interoperability determines the ability of tags and readers manufactured by different suppliers to work interchangeably—to be, in fact, plug-and-play. This is critically important to end users, who simply need to know that the Gen 2 readers they've installed in their warehouses, distribution centers, or retail stores will read all the Gen 2 tags that come through their doors—regardless of what company or companies manufactured them. And products are either fully interoperable, or they're not interoperable at all. In order to achieve an interoperability certification, a tag must pass all 267 test suites (defined by EPCglobal and their testing partner, MET Labs) with each reader and each printer-encoder. Likewise, a reader or printer-encoder must pass its set of test scenarios with each tag. When they do, they earn the right to bear EPCglobal's UHF Gen 2 interoperability "mark."

The process of interoperability certification allows EPCglobal to verify the correct operation of tags with a reference reader system, and readers with a reference tag system (Impinj's Monza tag silicon and Speedway reader are key elements in this "golden" reference system). The interoperability testing covers the vast majority of cases users can expect to see in the field, providing the assurance that both tags and readers—even those from various manufacturers—will respond properly. To this end, test suites are created by assembling a group of test cases that exercise the major functionality subsets of the Gen 2 protocol. Four test suites were defined for certification purposes: Select/Inventory, Memory Access, Permalock/Kill, and Special (optional). Each test suite is run for a given set of reader/tag air interface conditions. (The set of parameters that define the air interface settings is called the mode, which defines the user-settable reader-to-tag characteristics (data rates, modulation schemes, etc.), as well as the tag-to-reader characteristics.)

Now, interoperability testing would be unnecessary if EPCglobal's testing partner, MET Labs, could design test procedures for conformance testing that completely exercise the tag and reader. But this is not possible. Particularly in a lab. While the authors of the Gen 2 standard worked to ensure that the spec is as explicit and unambiguous as possible, there remains the opportunity for misinterpretation. What's more, there are a great many variables in any sequence of commands that might be issued by a reader. In fact, given the complexity of options and modes of operation available in Gen 2, there is practically an infinite number of possibilities in the way that a reader can communicate with a tag, both in terms of the commands it can send and what it can ask the tag to do.

Click Here To Download:
•RFID White Paper: UHF Gen 2 Interoperability