C1G2 standard revs up RFID

Initiatives from retailers and the U.S. Department of Defense to launch passive radio frequency identification in the supply chain affect consumer, pharmaceutical and defense manufacturers. However, the lack of globally accepted standards and the limited functionality of current, proprietary, passive RFID technology, hinders wide-scale adoption.

To address these challenges, EPCglobal , the international RFID standards body, recently approved a standard called Class-1, Generation-2 (C1G2). The standard specifies the communications protocols between RFID tags and readers in the ultra-high frequency (UHF), or 860- to 960-MHz, range. Test quantities of C1G2 tags already are shipping, and production quantities of the tags will be available in the third quarter.

C1G2 creates a specification that is faster, more secure, globally recognized and, eventually, less expensive to deploy. It also provides a royalty-free framework toward which all major technology producers - including chip, reader, label, printer and software providers - can build. This will help drive adoption and bring down cost.

The standard already has been accepted in Europe and North America. China is expected to ratify the C1G2 standard by year-end.

C1G2 increases tag-read speeds to roughly 1,500 reads per second in the U.S. (600 reads per second in Europe), compared with 100 to 300 for current tags. Write speeds are twice as fast as those achievable with C1G2. This is especially critical because RFID is deployed within manufacturing lines and other high-speed environments. For example, a typical consumer-goods manufacturing line can move at 200 cases per minute and a pharmaceutical bottling line can move at 400 bottles per minute, both well beyond the write capability of current tags and readers.

C1G2 also substantially improves security. The original focus of the Class 0 and C1G1 legacy specifications was for supply-chain case and pallet deployments. As RFID spreads to usage on individual items such as pharmaceuticals and, eventually, items on the store shelf, security will become much more important (protecting the tag information and users' privacy). The standard includes functionality to password-protect read access and permanently lock memory contents, and increases the "kill" password length from eight to 32 bits.

C1G2 implements a sophisticated anti-collision algorithm that greatly improves the ability of the reader to read large numbers of tags in the read field at one time. This anti-collision algorithm, along with the utilization of spread-spectrum techniques, allows readers to selectively communicate with individual tags at different frequencies within the accepted range.

Lastly, the C1G2 specification addresses cross-reader interference. The read range for UHF can be 10 to 20 feet in open air. Situations such as opposing sides of the same dock door, side by side in point-of-sale configurations or daisy-chained on a conveyer line could result in cross-reader interference.

This standard defines three different modes or types of readers: Single-Interrogator, which is certified to work only when there are no other readers within a 1-kilometer, or 0.62-mile, radius; Multi-Interrogator, which can be deployed with 10 or fewer within a 1-kilometer radius; and Dense-Interrogator, which is certified to work alongside 50 or more readers within a 1-kilometer radius.

These and other features contribute to making C1G2 a robust method of rapidly and securely communicating information between RFID tags and readers. The C1G2 specification is a great start toward enabling enterprise deployment of RFID throughout the global supply chain.

How it works: Class 1, Generation 2

Oglebay is senior radio frequency engineer and Rice is vice president of technology for R4GS. They can be reached at doglebay@ r4gs.com and crice@r4gs.com, respectively.


Copyright © 2005 IDG Communications, Inc.

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