RFID Essentials: An Introduction to RFID–Part I

In Twelfth Night, Shakespeare wrote, “Some are born great, some achieve greatness, and some have greatness thrust upon them.” RFID is one of the more recent four-letter abbreviations to have greatness thrust upon it in a flurry of industry mandates, governmental legislation, and hyperbole.

RFID stands for Radio Frequency Identification, a term that describes any system of identification wherein an electronic device that uses radio frequency or magnetic field variations to communicate is attached to an item. The two most talked-about components of an RFID system are the tag, which is the identification device attached to the item we want to track, and the reader, which is a device that can recognize the presence of RFID tags and read the information stored on them.

The reader can then inform another system about the presence of the tagged items. The system with which the reader communicates usually runs software that stands between readers and applications. This software is called RFID middleware. Figure 1 shows how the pieces fit together.

Much of the recent interest surrounding RFID has arisen from mandates and recommendations by government agencies such as the U.S. Department of Defense (DoD) and the Food and Drug Administration (FDA), and from a few private sector megacorporations. For instance, in an effort to improve efficiency, Wal-Mart called for its top 100 suppliers to begin providing RFID tags by early 2005 on pallets shipped to its stores. This mandate caused the companies in Wal-Mart's supply chain to focus on implementing RFID solutions. Companies worked to decide which tags and readers to use, how to attach tags to (or embed them in) containers or products, and how to test the read rates for RF tags on pallets as they moved through doors and onto trucks. Several companies have announced their support for what are now commonly known as tag and ship applications, which tag a product just before shipping it somewhere else, but few of these companies have moved beyond minimum compliance with the mandates to using the information on RFID tags to increase efficiency in their own internal processes.

Figure 1. Spreadsheet of CCDiscs and days

The mandates have also focused most of these early implementations on tagging, and thus on the physical side of the RFID systems. However, while it is important to both select tags and readers and find just the right arrangement of antennas to recognize tags as they move through docks and conveyor belts, the true benefit (and complexity) of RFID systems doesn't come from reading the tags, but from getting the information from those reads to the right place in a usable form.

The first 100 were only the beginning of the Wal-Mart RFID rollout. Many more suppliers will be tagging pallets and cartons and some individual items by the end of 2006. Meanwhile, the biggest news in RFID may surround the ePedigree initiatives aimed at reducing counterfeiting and improving efficiency and safety in the distribution of pharmaceuticals. By then, many more new initiatives will have been launched to apply RFID to other industries in ways we can hardly predict (although we'll try in Chapter 11).

In the pages to come, we explain the essentials of an RFID system, and in order to put these concepts in perspective, we will also briefly discuss the history, current status, and future of the technology. This book will give you the information and understanding you need to take on your first RFID project, but we hope you'll find it just as useful once you become a seasoned veteran in the field.

The Case for RFID
RFID technologies offer practical benefits to almost anyone who needs to keep track of physical assets. Manufacturers improve supply-chain planning and execution by incorporating RFID technologies. Retailers use RFID to control theft, increase efficiency in their supply chains, and improve demand planning. Pharmaceutical manufacturers use RFID systems to combat the counterfeit drug trade and reduce errors in filling prescriptions. Machine shops track their tools with RFID to avoid misplacing tools and to track which tools touched a piece of work. RFID-enabled smart cards help control perimeter access to buildings. And in the last couple of years, owing in large part to Wal-Mart and DoD mandates, many major retail chains and consumer goods manufacturers have begun testing pallet- and case-level merchandise tagging to improve management of shipments to customers.

Part of what made the growth in RFID technologies possible were the reductions in cost and size of semiconductor components. Some of the earliest RFID tags were as big as microwave ovens, and the earliest readers were buildings with large antennas, as described in Chapter 3. Figure 2 shows a modern RFID tag (in the clear applicator) and a reader.

Figure 2. A tag and reader (image courtesy of Merten G. Pearson, D.V.M.)

Note how the bar code on the applicator matches the code read on the reader. The tag is inside the applicator in this picture and is about the size of a grain of rice. It's very similar to the glass capsule tag shown in Figure 3.

Figure 3. The VeriChip is smaller than a dime (image courtesy of Applied Digital)

Like RFID tags, the size of tag readers is shrinking. While most tag readers are still the size of a large book, smaller and less expensive readers may open up opportunities for many new RFID applications that, over the coming years, could become a normal and mostly unnoticed part of our lives. Figure 4 shows one of the smallest readers currently available.

As individuals, we must consider what impact this technology will have on our lives. Such an efficient and unobtrusive tracking mechanism can be used in ways that raise concerns about individual privacy and security. As citizens, we must understand the benefits and costs of this technology and its impact on us. Conversely, as developers, we know that “unobtrusive” is a euphemism for “works correctly because a great deal of effort went into design, implementation, and testing.” It is our job as managers, architects, and developers to make the technology work so well that it disappears. The following pages will provide an introduction to how RFID works.

Figure 4. SkyeTek's SkyeRead M1-mini (image courtesy of SkyeTek)

Advantages of RFID over Other Technologies
There are many different ways to identify objects, animals, and people. Why use RFID? People have been counting inventories and tracking shipments since the Sumerians invented the lost package. Even some of the earliest uses of writing grew from the need to identify shipments and define contracts for goods shipped between two persons who might never meet. Written tags and name badges work fine for identifying a few items or a few people, but to identify and direct hundreds of packages an hour, some automation is required.

The bar code is probably the most familiar computer-readable tag, but the light used to scan a laser over a bar code imposes some limitations. Most importantly, it requires a direct “line of sight,” so the item has to be right side up and facing in the right direction, with nothing blocking the beam between the laser and the bar code. Most other forms of ID, such as magnetic strips on credit cards, also must line up correctly with the card reader or be inserted into the card reader in a particular way. Whether you are tracking boxes on a conveyor or children on a ski trip, lining things up costs time.

Biometrics can work for identifying people, but optical and fingerprint recognition each require careful alignment, similar to magnetic strips. Facial capillary scans require you to at least face the camera, and even voice recognition works better if you aren't calling your passphrase over your shoulder. RFID tags provide a mechanism for identifying an item at a distance, with much less sensitivity to the orientation of the item and reader. A reader can “see” through the item to the tag even if the tag is facing away from the reader.

RFID has additional qualities that make it better suited than other technologies (such as bar codes or magnetic strips) for creating the predicted “Internet of Things.” One cannot, for instance, easily add information to a bar code after it is printed, whereas some types of RFID tags can be written and rewritten many times. Also, because RFID eliminates the need to align objects for tracking, it is less obtrusive. It “just works” behind the scenes, enabling data about the relationships between objects, location, and time to quietly aggregate without overt intervention by the user or operator.
To summarize, some of the benefits of RFID include the following:

  • Alignment is not necessary–A scan does not require line of sight. This can save time in processing that would otherwise be spent lining up items.
  • High inventory speeds–Multiple items can be scanned at the same time. As a result, the time taken to count items drops substantially.
  • Variety of form factors–RFID tags range in size from blast-proof tags the size of lunch boxes to tiny passive tags smaller than a grain of rice. These different form factors allow RFID technologies to be used in a wide variety of environments.
  • Item-level tracking–Ninety-six-bit RFID tags provide the capability to uniquely identify billions of items (more about this in Chapter 3).
  • Rewritability–Some types of tags can be written and rewritten many times. In the case of a reusable container, this can be a big advantage. For an item on a store shelf, however, this type of tag might be a security liability, so write-once tags are also available.

The Promise of RFID
As previously mentioned, the capability to attach an electronic identity to a physical object effectively extends the Internet into the physical world, turning physical objects into an “Internet of Things.” Rather than requiring human interaction to track assets, products, or even goods in our homes, applications will be able to “see” items on the network due to their electronic IDs and wireless RF connections.

For businesses, this can mean faster order automation, tighter control of processes, and continuous and precise inventories. Business partners will finally be able to share information about goods end to end through the supply chain and, just as importantly, to instantly identify the current location and status of items. For example, pharmacists will be able to track how long perishables have been out of refrigeration.

Military personnel, law enforcement officers, and rescue workers may soon use RFID tags to help build and configure complex equipment based on rules enforced by tag readers. RFID already tracks expensive and sensitive assets used in each of these fields.
For individuals, RFID could provide more effortless user interfaces–a so-called “smart” systems that could tell you, for example, which clothes in your closet match. Smart medicine cabinets could warn you against taking two drugs that might interact negatively.

It's even conceivable that supermarkets of the future may not have checkout stands–you may fill your cart with goods that a reader in the cart will scan and add to your total. Video monitors on the shelves will offer specials on complementary products; they may even offer to guide you to all of the ingredients for a recipe, based on some of the items you've already chosen. As you walk out the door, you will place your thumb on a pad on the cart handle to approve payment. A shoplifter, however, wouldn't make it very far before the readers recognized unpurchased items passing beyond the sales floor.

Some of these applications are already running in pilot stages. Libraries and video stores use RFID to thwart theft. Some shoppers in Japan use RFID-enabled cell phones to make purchases from vending machines. Businesses use RFID to track goods, and animal tracking has been around for years.

RFID will enter the home and the supermarket aisle when the prices of readers and tags become low enough and when the information infrastructure to use and maintain the new technology is in place. Some of these applications may seem far-fetched, but they are things we know we can do with a bit of engineering. What RFID promises most is to surprise us with uses we can't even imagine at this stage of adoption. For more on the future of RFID, see Chapter 11.

Next: The Eras of RFID

Title: RFID Essentials
Authors: Bill Glover, Himanshu Bhatt
ISBN: 9780596009441
To Purchase: O’Reilly Media Catalog
Copyright 2006 O'Reilly Media, Inc. All rights reserved. Used with permission.

Next: The Eras of RFID

About the Authors
Bill Glover makes his living explaining simple concepts to complex people who tend to work for large companies. Bill believes that anything you do three times should be scripted, and that if a piece of code is 100 lines long it can probably be done better in 10. Bill is a Pisces who enjoys long walks in the hills, full personal state vector uploads and chatting about completely harmless things over strong, public key encryption. He can be reached at:

Himanshu Bhatt heads Sun Microsystem's US RFID & Sensor Solutions Practice. His responsibilities include developing go-to-market strategies and execution plans, developing partnerships with select ISVs, IHVs, and Systems Integrators, people management and all aspects of RFID related sales and delivery for the US market. As the head of the US RFID efforts for Sun, Himanshu developed strong working relationship with product engineering, marketing and industry partners. Prior to leading the charge for the RFID practice, Himanshu has managed the technical sales and consulting practices for Java and related Sun Software products. Himanshu started his career as an enterprise architect and has published papers and spoken at industry conferences on various areas of J2EE and enterprise software architecture.

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