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How to Select a Correct RFID Tag – Standards & Mandates
Let’s discuss various standards related to the design and use of RFID systems as well as a few RFID mandates issued by some commercial and governmental organizations, which drive a large part of RFID implementations today.
Standards are created by various organizations to facilitate interoperability among components of the system designed and manufactured by many different organizations. Many organizations develop standards—for example, the International Organization for Standardization (ISO), American National Standards Institute (ANSI), and EPCglobal.
While more than one standard may be available for a particular use and compliance with it is optional, regulations must be obeyed. Mandate compliance is optional. Mandates are created by organizations as a policy to interact with various business partners. The following sections describe various RFID standards and mandates that will effect the selection of a particular tag.
This section covers some of the important standards that you need to know when selecting an RFID tag or designing an RFID system.
The ISO/IEC 18000 series of standards has seven parts and deals only with the air interface protocol. The standards define use of five frequency bands for communication between interrogator and tags. Let’s review only the most important parts.
Part 2 specifies parameters for air interface communications between the interrogator and the tag below 135 kHz frequency (low frequency tags). This part defines protocol, commands, and methods for detecting and communicating with one tag among several tags (anti-collision), but the implementation of anti-collision is optional.
This standard provides parameters for air interface communications at the 13.56 MHz frequency. It defines the physical layer, collision management system, and protocol values for RFID systems for item identification operating at 13.56 MHz frequency (high frequency tags).
This standard defines the communications protocol used in the air interface for RFID devices operating at the 2.45 GHz frequency used in item management applications. This standard defines two modes. The first mode is for passive tags operating as an interrogator talks first (ITF), while the second mode is for battery-assisted tags operating as a tag talks first (TTF).
This standard describes the physical interactions between the interrogator and the tag, the protocols and the commands, and the collision arbitration schemes for passive RFID systems operating within the 860 to 960 MHz frequency range (UHF). The standard describes three non-compatible Types A, B, and C, where Types A and B are rarely used and Type C is equivalent to the EPCglobal Gen 2 standard.
Part 7 defines the air interface for RFID devices operating as an active RF tag in the 433 MHz band used in item management applications. Typical applications operate at ranges greater than 1 meter. It was developed for FCC-approved read/write active tags. These tags are used by US DoD and Universal Postal Union and have a read range in excess of 300 feet.
This standard defines identification cards operating at the 13.56 MHz frequency using near-field inductive coupling. The cards are usually called proximity cards. Typical applications include identity, security, payment, mass-transit, and access control. ISO 14443 systems are designed for a range of about 10 centimeters (3.94 inches), so they are a good fit for applications such as vending machines.
ISO 15693 is an ISO standard for vicinity cards, which can be read from a greater distance compared to proximity cards defined by ISO 14443. ISO 15693 systems operate at the 13.56 MHz frequency, use near-field inductive coupling, and offer maximum read distance of 3 to 5 feet. This range makes them a good fit for applications such as physical access or controlling entry to a parking garage, also serves as the foundation for a variety of applications outside of contactless smart cards, such as airline baggage tracking and supply chain management.
This standard is officially called EPC Radio-Frequency Identity Protocols Class 1 Generation 2 UHF RFID protocol for communications at 860–960 MHz. It was developed by EPCglobal, Inc. in 2004, which is now GS1, and was approved as ISO 18000-6C in July 2006. It defines air interface parameters for tags operating within the frequency range of 860–960 MHz and allows for use of different frequencies in different regions from within this range.
There are several versions of this standard and the latest version Gen2v2 (that was first introduced in 2013) 2.0.1. (ratified in 2015) introduces several new features to the protocol.
You will see Gen 2, C1G2, Class 1 Generation 2, or ISO 18000-6c, but all of these terms refer to the above-mentioned EPC Radio-Frequency Identity Protocols Class 1 Generation 2 UHF RFID protocol for communications at 860–960 MHz developed by EPCglobal (now GS1) and ratified by the ISO.
Key Gen2 features are as follows:
• Ability to change encoding according to the environment The reader changes the encoding method, the Miller sub-carrier or FM0, according to the noise in the environment. In a low-noise environment it may use FM0 encoding, which is faster, but as noise increases it may switch to Miller sub-carrier, which is designed to optimize performance in noisy and dense reader environments. This decreases the number of tags read per second but allows tags to be read in harsher environments.
• Three modes for reader operation The reader may operate in single, multi, and dense environments. A dense reader environment is designed for enterprise deployments in which hundreds of readers are operating at the same time.
• Tag population management Provides select, inventory, and access commands for efficient reading of tags—for example, a group of tags may be selected with a wild card pattern.
• Longer kill and access passwords 32-bits-long access and kill passwords increase the level of security for the data on the tags.
• Forward link data protection Tags provide a randomly generated number to the reader to encode the data sent by the reader to the tags.
• Four sessions for tag inventory Tag may operate in four different sessions at the same time, so four different readers can communicate with the tag at the same time without interfering with each other.
• More robust tag communication design Reduces potential for ghost reads and entry of erroneous data into the application.
• Faster data transmission rate up to 640 Kbps This is five times faster than the previous standards.
• Improved tag memory and programmability Tag memory is divided into four banks. A bank may have read-only, write once, and read/write parts within it. This provides better tag security and application flexibility.
• Q Algorithm Provides faster resolution of tag collision and increased security for communication between tag and reader.
GEN2V2 UPGRADES TO GEN2 (V1) INCLUDE:
• Function for untraceability, which allows to hide portions of data, restrict access privileges and reduce a tag’s read range.
• Support for cryptographic authentication of tags and readers, to verify identity and provenance, as well as reduce the risk of counterfeiting and unauthorized access.
• Enhanced User Memory for supplementary encodings (such as maintenance logging) during a product’s life cycle.
• “Non-removable” tag for embedded tagging of electronics and sewn-in tagging of apparel, to indicate that a tag cannot easily be removed without compromising the tagged product’s intended functionality.
To learn more about Gen2v2, check out this Fact Sheet and also GS1 website.
EPC TAG DATA STANDARDS, VERSION 1.9 (PUBLISHED JULY 2014)
This standard defines EPC tag data formats for Generation 2 tags. It defines how the EPC is encoded on the tag and how it is encoded for use in the information systems layers of the EPC Systems Network. The standard includes specific encoding schemes for EPC General Identifier (GID). It also defines encoding of six other numbering systems for 96 bits used in global trade:
• SGTIN (Serialized GTIN) – Serialized EAN.UCC Global Trade Item Number
• SSCC – EAN.UCC Serial Shipping Container Code
• GLN – EAN.UCC Global Location Number
• GRAI – EAN.UCC Global Returnable Asset Identifier
• GIAI – EAN.UCC Global Individual Asset Identifier
• DoD – US Department of Defense number
FORMAT OF EPC GID-96
|Region||HEADER||GENERAL MANAGER NUMBER||OBJECT CLASS NUMBER||SERIAL NUMBER|
|GID-96||8 bits||28 bits||24 bits||36 bits|
|Decimal capacity||0011 0101 |
Mandates are created by large organizations (Walmart is a best known example, but also Target, Zara, Marks & Spencer, U.S. Department of Defense (DoD) and many others) that buy goods from many suppliers located around the world. Their goal is to create, by using RFID, a more efficient supply chain and thereby reduce costs. As with standards, compliance with mandates is not required, but noncompliance may affect your relationship with the mandating organization—for example, you may not be able to do business with them. All the mandates require use of UHF systems, and almost all of them now require the use of Gen 2 tags (except of the U.S. DoD, which uses mostly active RFID tags at 433 MHz and passive Gen 2 for only some applications).
All the mandates are phased in over a time period of more than one year and include using RFID tags on pallets and cases of items shipped. No item-level tagging has been mandated yet. Mandates also require some sort of electronic document to be sent to the customer with a list of all the tag numbers shipped. Many suppliers, particularly small companies, have started placing RFID tags on cases and pallets just before shipping them. This is typically called “tag and ship” or “slap and ship.” The companies using slap and ship are incurring the cost of the RFID system but are not getting any benefits from it. One advantage of mandates is that they have accelerated the use of RFID. Without the mandates, many companies would not have quickly adopted RFID.