The Little Chip That Could - part 2

RFID (Radio Frequency Identification) and the “Internet of Things”

by David C. Wyld

The following article is the second part of a two part installment on the subject of RFID technology and its implications. The first installment appeared in Volume 4, Issue 2 of Security Shredding and Storage News.

Radio Frequency Identification (RFID) technology is a derivative of the experiments of the famous scientist Heinrich Hertz, who discovered in the late 1800's that radio frequencies can be used to reflect waves from objects. This discovery led to the invention of radar and many other now familiar technologies. The specific concept of RFID, however, is credited to Harry Stockman, the man who laid out the technology's basic principles in 1948. Fast forward over fifty years later, and Stockman's idea is a reality. Today, RFID technology makes it possible for bits of data to be transferred via radio waves from special tags placed on objects to a “reader” device that collects and interprets the transmitted information. Through RFID technology, items can be tracked and monitored with a greater level of accuracy and depth of information than ever before. In the past, prohibitive costs and technological restrictions rendered RFID impractical, but recent improvements in functionality and greatly reduced production costs have positioned RFID as a serious contender to the now ubiquitous bar code.

RFID tags hold many advantages over bar codes. For instance, they are extremely versatile, and can be adjusted to various radio frequencies to achieve a particular desired result. Frequency designates the intensity of the radio waves used to transmit information. It is of primary importance when determining data transfer rates (bandwidth). The higher the frequency, the higher the data transfer rate. In principle, an RF system works much akin to your car radio. For instance, all FM radio stations in the U.S. must operate between 88 and 108 MHz. Thus, if you are currently tuned to 97.1 FM, it means that your radio is tuned to receive waves repeating 97.1 million times per second.

There are four common frequencies used in RFID systems. Each of the four frequencies has its own properties, and there are a variety of reasons why each is used in specific applications. An overview of the characteristics of each frequency range is provided in Table 1. The radio frequencies involved in RFID are all in the safe range. 13.56 MHz is between the AM and FM frequencies that have been used for years in commercial radio transmissions without any known problems. The maximum power level in the U.S. and most countries is limited to four watts. 915 MHz is around the analog cell phone spectrum and has not been found to cause any health concerns at levels below one watt. 2.45 GHz is around the frequency of the newer digital cell phones. At one watt or less, there have been no proven health concerns.

Table 1 – Characteristics and Applications of RFID Frequency Ranges

Frequency Band	System Characteristics	Example Applications
Low (LF) 100-500 kHz (Typically 125 to 134 KHz worldwide)	Short read range (to 18 inches) Low reading speed Relatively inexpensive Can read through liquids Works well near metal	Access control Animal identification Beer keg tracking Inventory control Automobile key / anti-theft systems
High (HF) (Typically 13.56MHz)	13.56 MHz frequency accepted worldwide Short to medium read range (3 – 10 feet) Medium reading speed Can read through liquids/ works well in moist environment Does not work well near metal Moderate expense	Access control Smart cards Electronic article surveillance Library book tracking Pallet/container tracking Airline baggage tracking Apparel/laundry item tracking
Ultra High (UHF) 400-1000 MHz (Typically 850-950 MHz)	Long read range (10-30 feet) High reading speed Reduced likelihood of signal collision Difficulty reading through liquids Does not work well in moist environments Experiences interference from metals Relatively expensive	Item management Supply chain management
Microwave 2.4-6.0 GHz (Typically 2.45 or 5.8 GHz)	Medium read range (10+ feet) Similar characteristics to UHF tags, but with faster read rates	Railroad car monitoring Toll collection systems

Frequency restrictions imposed by governments around the world have been a significant obstacle facing RFID development. For instance, while Europe uses 868 MHz for UHF systems and the U.S. uses 915 MHz, Japan and China currently do not allow any use of the UHF spectrum for RFID. However, progress is being made in the effort to harmonize world standards in each of the four frequency ranges.

The read range refers to the working distance between a tag and a reader. The range that can be achieved in an RFID system is determined by five variables. These are:

The frequency being used.
The power available at the reader.
The power available within the tag.
The size of the reader and tag antennas.
Environmental conditions and structures.

As seen in Table 1, higher frequencies tags have far greater read ranges than tags operating at lower frequencies. This is because all things being equal, power is the key element in this process. In the previously described energy harvesting technique that is employed to power passive tags, it is important to note that the process only returns the signal with a fourth of the power transmitted to power it up. Thus, according to findings by the National Research Council, to double the read range of a passive tag the power used must be increased sixteen times.

Finally, as is the case with so many technologies, while the physics are relatively simple, the devil is in the details. It is often difficult to get readers and tags to properly communicate. While the goal is for the technology to be “automatic” and hands-off with 100% read rates, such has not always been the case in pilots and early implementations. There are several variables that can dramatically affect read rates in practice. These include: tag selection and placement, antenna selection and placement and reader settings. It must be remembered that experiments and pilots of tags and readers in controlled circumstances represent the best possible scenarios for readability. As the shift is made to actual warehouse conditions and higher quantities/higher speeds, readability can be significantly challenged.

There are many seemingly extraneous factors which can complicate the reading process. For instance, when metal or water is present, either in the item itself or in the reading field, it can cause significant declines in read rates. This is because liquids absorb radio waves and metal reflects them. Much has been written about the technical problems of dealing these phenomena. For example, when dealing with the tagging of aircraft parts and even luggage tracking, the metals present in the aircraft must be taken into consideration. Likewise, there are problems in dealing not just with the presence of water and humidity in the environment, but also high water content in the packaging and in the items being tagged. These include, but by no means are limited to: fruit, beer and wine. However, the newest, second generation RFID tag technology (GEN 2) seems to perform better around liquids and in metallic environments.

In any setting in which RFID is used, there is the potential for radio signal interference to occur. When this happens, the read rates – and therefore the functionality of the entire system – can be hampered on anything from a minor to catastrophic level. For instance, Douglas Martin, an Executive Consultant with IBM Global Services, observed that in IBM's work with Wal-Mart on a pilot project involving the backrooms of seven stores' grocery operations, interference was found emanating from a number of sources. These sources included walkie-talkies, forklifts, cell phone towers and even bug zappers. Likewise, Hewlett-Packard has reported that in some cases when their forklift drivers used their cell phones it caused misreads of RFID tags. Sometimes the human element comes into play, as workers need to be informed that it is important that they drive the forklift at a certain speed past a certain point or apply a smart label at a precise location on a carton, in order for the RFID tags to be read properly.

Making RFID systems work in practice – with 100% read accuracy – is thus a complex matter. Every location where RFID is to be used and every item to be read by RFID presents its own unique set of circumstances. Thus, at present, there is no “one best way” to accomplish RFID. In fact, L. Allen Bennett, the President and CEO of System Concepts, an RFID integrator providing services to the Social Security Administration and other organizations, provided an apt analogy when he stated that RFID implementations are “a little like Chinese cooking,” in that all the ingredients have to be prepared “right” and be combined in the proper manner.

Analysis

Microsoft has outlined the following RFID-enabled vision of retailing in the future: Imagine a shopping cart equipped with a scanner and a touch-screen computer that acts as a virtual personal shopper. As you scan items and put them in your cart, the computer offers information about each product and suggests complementary items. The computer keeps a list of the items in your cart with a running total so you know exactly how much you're spending. When finished shopping, you head to a self-checkout stand or to a cashier. Because your items are already totaled and bagged, the wait time is minimal. All you have to do is pay (n.p.).

Already, Metro, the world's fourth largest retailer and the largest German retail chain, has assembled such a store of the future Rheinberg , Germany (Van Osten, 2006). While it will take a few years for RFID to become commonplace on retail store shelves RFID is already being used in a wide variety of creative applications. For example:

A worker at a distribution center can instantly identify each and every one of the items contained in every box on a pallet on the tongs of the forklift she is driving.
A librarian can locate a book that had been incorrectly shelved.
A worker at a livestock processing facility can instantly access the identity and history of a cow.
A hospital can locate critical medical devices instantly, wherever they are located throughout the facility.
A blood bank can track its inventory with greater accuracy.
A pharmacist can tell that two bottles in his supply of a highly addictive prescription drugs are counterfeit.
A military contractor in Baghdad can instantly locate the necessary spare to repair a Blackhawk helicopter for an imminent mission.
A casino can track its table game players' activity with great accuracy, enabling it to better reward its key players with free benefits and retain them as customers.
An art museum can use RFID-enabled exhibits to provide enhanced visitor experiences by making exhibits come “alive.”
A golfer can instantly locate his errant shot and retrieve the ball from the thicket where it landed.

RFID is an exciting technology, one which is poised to enter our lives in many new ways over the next decade. Futurist Paul Saffo foresees that much of the focus on RFID today is on doing old things in new ways, but the truly exciting proposition is the new ideas and new ways of doing things that will come from RFID. He predicts that “RFID will make possible new companies that do things we don't even dream about.” As such, this new, old technology will become one of the driving forces of the 21 st century. It will pay to be aware of it and explore ways to make it work for you and your company.

David C. Wyld is the Robert Maurin Professor of Management at Southeastern Louisiana University, where he directs the College of Business' Strategic e-Commerce/e-Government Initiative and teaches business strategy. He is a noted RFID speaker/consultant/writer, being a frequent contributor to Global Identification, RFID News and other industry publications. He is also the author of the recent research report, “RFID: The Right Frequency for Government,” issued by the IBM Center for the Business of Government. The complete report can be downloaded free of charge from the IBM Center's website at www.businessofgovernment.org.