Jan 31, 2006At a meeting of the Auto Industry Action Group (AIAG) last week in Detroit, an ad hoc team of International Organization for Standardization (ISO) and EPCglobal representatives provided a roadmap for realizing a proposal to enable the EPCglobal UHF Gen 2 air-interface protocol protocol to accommodate other data formats used by not just the auto industry, but other vertical industries, as well. The group spearheaded the effort to develop the proposal, which it plans to submit to ISO's U.S. Technical Advisory Group (US TAG) for consideration, once ISO ratifies Gen 2 as ISO 18000-6c, which is expected to happen soon.
In December, Sue Hutchinson, the EPCglobal US director of product development, made a proposal to the AIAG that its members utilize the "user memory" portion of the EPC Gen 2/ISO 18000-6c protocol to encode with industry-specific data. Such data would include the U.S. Department of Transportation (DOT) tire identification number, which provides information on its manufacturing date and location, into a tag (see Auto Industry RFID Data Standard Proposed). However, the group had not yet figured out how an RFID interrogator would access that user memory.
Specifically, the proposed revision is to use a bit (bit 15) within memory bank 01 of the protocol control section of the unique item identifier (UII) of the ISO 18000-6c and EPCglobal UHF Gen 2 air-interface protocol to indicate whether a user (e.g., Michelin) has encoded data to the user memory portion of the 18000-6C-compliant tag. Within this user memory, a tire maker would encode industry-specific data, such as the DOT tire ID. If the RFID interrogator reads bit 15 as a 1, indicating user memory is being used, it would then read the data within user memory. If bit 15 is a 0, the interrogator would not attempt to read the user memory section of the code.
This approach, sometimes referred to as a toggle bit, is already used within the Numbering System Identifier (NSI) field of the Gen 2 protocol to identify whether the tag uses an EPC, such as a serialized Global Trade Item?Number or a Serial Shipping Container Code, or an ISO Application Family Identifier (AFI), such as a part identification number or a unique item number called a license plate number (see Gen 2 Finds a Path to ISO Approval).
Using both of these toggle bits (bit 17 within the code's NSI and bit 15 within the UII), a tag encoded with the proposed revision could identify itself as one of four things: as an EPC (bit 17 is 0) with user memory (bit 15 is 1); an EPC (bit 17 is 0) without user memory (bit 15 is 0); an AFI (bit 17 is 1) with user memory (bit 15 is 1); or an AFI (bit 17 is 1) without user memory (bit 15 is 0).
The proposed revision also calls for the user memory to be formatted in compliance with the ISO 15961 and 15962 RFID data protocols, which were designed to provide a means of seeking out specific data from a tag, such as a unique identifier or an expiration date or lot number. "Say, all I want to read is the DOT code," explains Craig Harmon, president and CEO of information system consultancy QED Systems and US TAG SC 31's senior project editor for ISO 18000 air-interface standards. "The 15961/15962 protocol tells the [RFID interrogator] how to get that data."
The AIAG follows the B-11 Tire and Wheel Label and RFID Standard, which provides uniform methods for identifying each individual tire with unique tire information. It created the B-11 in response to the Transportation Recall Enhancement, Accountability and Documentation Act (TREAD Act), which the U.S. Congress passed in November 2000, requiring all tires on new model cars to be tracked individually. The B-11 conforms to the EPC numbering scheme so retailers and the Department of Defense can use the EPC for inventory purposes. Initially, however, the B-11 standard called for EPC information to be included in a tag using a data identifier format, which the DOD and retailers wouldn't accept. With the new proposal, AIAG has also agreed to place EPC data in the tag's unique item ID (UII) memory, which is compatible with retailer and DOD mandates.
The 18000-6c revision will, if ISO approves it, signify a breakthrough for companies such as Michelin. The developers of the proposal believe it will also provide a mechanism for firms in many other industries, such as pharmaceuticals or aerospace, to encode an EPC and an industry-specific code onto the same RFID tag.
"This concept may apply to a lot of different industries," says Hutchinson, cautioning that the application of this approach might not be as easy for other industries to adopt. "The tire folks have a good concept for exactly what they'll need for user memory. Other industries have less certainty."
"This [proposal] is a watershed in expanding cooperation between EPCglobal and the ISO community. We had some really good people looking at how this should be constructed," says Harmon, who worked closely with Hutchinson, AIAG members and other ISO committee members, on the proposal.
The proposal includes the following next steps: EPCglobal and ISO must accept and approve the use of bit 15 to indicate whether data is encoded to the tag's user memory; EPCglobal must reference the use of ISO 15962-compliant data structure for the user memory; and AIAG, with the support of overseas auto industry organizations Odette International in Europe, the Japan Automotive Manufacturers Association (JAMA) and the Japan Auto Parts Industries Association (JAPIA), must submit the revision to ISO through the US TAG SC 31.
Harmon says he would like to see EPCglobal vet the proposed revision through its appropriate working groups. By the time the revision enters the ISO balloting process—roughly four months from now—the two organizations would be in sync.
"This [proposal] is of massive importance," says Pat King, global electronics strategist at Michelin, "because we don't want to put an EPC on one tag and a industry ID on another. But this could work not just for the auto industry, but for other industries as well. In the December meeting, EPCglobal said this could happen, but the [Jan. 25] meeting showed how it could happen."
Harmon notes that the revision proposal will not affect the ISO 18000-6c standardization process, which is expected to wrap up next month with a final ratification. The process to revise 18000-6c will not begin until the standard is ratified.
