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The Little Chip That Could - part 1
The Little Chip That Could - part 1
The Little Chip That Could - part 1
The Little Chip That Could - part 1
RFID (Radio Frequency Identification) and the “Internet of Things”by David C. Wyld
The following article is the first part of a two part installment on the subject of RFID technology and its implications. The second installment will appear in Volume 4, Issue 3 of Security Shredding and Storage News.
There is a revolution going on today in the way we identify and track things. RFID (radio frequency identification) is a radio-based automatic identification technology that already surrounds us. If your car was manufactured after 1994 it probably uses RFID to verify that it is your key in the ignition. If you have an Exxon/Mobil SpeedPass TM in your pocket, you're using RFID. If you have a toll tag on your car, you're using RFID. If you have checked out a library book, you've likely encountered RFID. If you've been shopping in a department store or an electronics retailer, you've most certainly encountered RFID in the form of an EAS (Electronic Article Surveillance) tag. RFID is being used today to identify and track high-value assets; military supplies in Iraq , containers in shipping and defibrillators in hospitals.
Very soon we will see RFID usage explode into the consumer realm, as the technology is positioned to supplement and soon replace the venerable bar code that has become the default identifier of consumer goods. Already, major retailers in the U.S. such as Wal-mart, Target, Best Buy, Albertson's and CVS are undertaking major initiatives to revamp both their supply chains and their store inventory management processes through RFID. This is merely a U.S. phenomenon. Major European retailers, led by Metro and Tesco, have ambitious plans to create the “store of the future,” with RFID being the centerpiece of their strategies.
The RFID marketplace is set to explode, as it has been forecast that the world market for RFID equipment, software and services will reach $15 billion in less than a decade. This exponential growth will mean tremendous economic opportunities for companies and individuals; with forecasts projecting that over 1.3 million jobs will be directly created in the U.S. by RFID technology by 2015.
In this article, we will first explore what RFID technology is and how it offers tremendous benefits over the omnipresent bar code technology in use today. Then we will examine some of the emerging applications for RFID technology in not just supply chain management, but in ways that will directly impact our daily lives and the economy and society as a whole, helping create what Forbes Magazine described as an “Internet of Things.”
What is RFID?
RFID is fundamentally based on the study of electromagnetic waves and radio, pioneered in the 19 th century. The idea of using radio frequencies to reflect waves from objects dates back as far as 1886 to experiments conducted by Heinrich Hertz. Radar was invented in 1922, and its practical applications date back to World War II, when the British used the IFF (Identify Friend or Foe) system to identify enemy aircraft. In 1948, Harry Stockman laid-out the basic concepts for RFID. However, it would take decades of development before RFID technology would become a reality. Since 2000, significant improvements in functionality, decreases in size and costs, and agreements on communication standards have combined to make RFID technology viable for commercial and governmental purposes.
Today, RFID is positioned as an alternative to the ubiquitous bar code. To best understand the power of radio frequency identification, it is first useful to compare RFID with bar code technology. Conceptually, bar codes and RFID are indeed quite similar, as both are auto-ID technologies intended to provide rapid and reliable item identification and tracking capabilities. The primary difference between the two technologies is the way in which they “read” objects. With bar coding, the reading device scans a printed label with an optical laser or imaging technology. However, with RFID, the reading device scans a tag using radio frequency signals. Thus, referring to RFID as “radio bar codes” (as many do) is a disservice that confuses the basics of the technology.
The specific differences between bar code technology and RFID are summarized in Table 1.
Table 1 - RFID and Bar Code Technology Compared
| Bar Codes | RFID |
| Bar Codes require line of sight to be read | RFID tags can be read or updated without line of sight |
| Bar Codes can only be read individually | Multiple RFID tags can be read simultaneously |
| Bar Codes cannot be read if they become dirty or damaged | RFID tags are able to cope with harsh and dirty environments |
| Bar Codes must be visible to be logged | RFID tags are ultra thin and can be printed on a label, and they can be read even when concealed within an item |
| Bar Codes can only identify the type of item | RFID tags can identify a specific item |
| Bar Code information cannot be updated | Electronic information can be over-written repeatedly on RFID tags |
| Bar Codes must be manually tracked for item identification, making human error an issue | RFID tags can be automatically tracked, eliminating human error |
It is also important to bear in mind the fundamental temporal differences between bar codes and RFID. With bar code technology, information on the item is obtained only when someone takes the action of scanning the bar code label with a reader, and only that particular reader. In contrast, an item tagged with RFID is always "turned on" and available to be read, sometimes by multiple readers at the same time. Thus, while a bar code labeled item can only be read discretely, an RFID-tagged item can be read or monitored continuously. Bar codes can only tell you where an item of a particular class was when it was last scanned, while RFID can tell you precisely where a particular item is presently.
Bar codes yield information indicating the category of an item. In contrast, an RFID tag can present much more robust serialized information on a specific item, identifying it as a unique thing. RFID tags are “supercharged” item identifiers compared to the bar code. This granular information can enable a whole host of applications that are unimaginable with bar code technology. However, the advantages of RFID do come at a significant cost in terms of additional infrastructure, plus the cost of RFID tags for items. Today, bar codes cost approximately 1/10 th of one-cent. With the ramping-up of production, increasing demand for RFID tags and economies of scale at work, the cost of RFID tags will rapidly decline from their price point of approximately a quarter today. As tag prices fall we will see growth from the millions of tags in use today to a projected 10 trillion tags annually by 2015.
Ultimately, it is likely that RFID will supplement, rather than supplant, bar code technology for tracking items in supply chain management and other applications in organizations. They will most likely coexist on product and shipping labels for at least the next decade. Indeed, some of the most creative and cost-beneficial applications may come from combining RFID and bar codes together, where RFID tags/labels may be used to identify large groups of items and bar codes remain as the tracking device for individual items.
How RFID Works
There are three necessary elements for an RFID system to work. These are tags, readers, and the software necessary to link the RFID components to a larger information processing system. In a nutshell, the technology works as follows: the tag is the unique identifier for the item it is attached to. The reader sends out a radio signal, and the tag responds to identify itself. The reader then converts the radio waves returned from the tag into data that can be passed on to an information processing system to filter, categorize analyze based on the identifying information. Kenneth Porad, who is in charge of Boeing's RFID program, explained that the technology works “like shining a flashlight at a mirror and reflecting the light back.” While this analogy is an easy way to explain the technology to a lay audience, an engineer might readily object, as it is not technically correct. This is because with RFID, the communication occurs through the transference of data not through audio or light, but over electromagnetic waves in radio frequency (RF) communication.
There are three essential components that combine to form an RFID tag. These are the chip, the antenna and the packaging that contains them. An RFID tag has at its heart an integrated circuit (IC) which contains the unique identifying data about the object to which is it is attached. One of the identifiers (but not the only one) that can be used to identify the item uniquely with a RFID tag is the EPC (Electronic Product Code). The IC is attached to a small antenna, which most commonly is a small coil of wires. The packaging of the tag contains and protects the IC and the antenna. This packaging can come in a variety of sizes and forms, and can be geared to meet the requirements of the specific application. In fact, RFID tags can take a variety of forms, including: smart labels, keys or key fobs, watches, smart cards, disks and coins (which can be attached to an item with a fastening screw), mount-on-metal (which creates a buffer between the tag and the item to reduce interference and increase readability) and glass transponders (which can be implanted under the skin of a human or other animal). Hitachi has developed the mu-chip, a very tiny (0.4 millimeter square) RFID tag that is the size of a grain of rice. As discussed previously, RFID tags can function in harsh environmental conditions and temperature extremes.
There are two basic categories of tags: passive and active. A summary of the differences between the two general categories is presented in Table 2. Passive tags are already very familiar to us, as we see simple examples of such in the form of the EAS tags used throughout the retail industry. A passive tag basically has no power source, and as such, it is only “on” and able to transmit information when it is within range of an RFID reader. Passive tags function through a process known as “energy harvesting,” wherein energy from the reader is gathered by the tag, stored momentarily and then transmitted back to the reader at a different frequency.
Table 2 - Differentiating Passive and Active RFID Tags
| Passive Tags | Active Tags |
| Operate without a battery | Powered by an internal battery |
| Less expensive | More expensive |
| Unlimited life (because of no battery) | Finite lifetime (because of battery) |
| Less weight (because of no battery) | Greater weight (because of battery) |
| Lesser range (up to 3-5 meters, usually less) | Greater range (up to 100 meters) |
| Subject to noise | Better noise immunity |
| Derive power from the electromagnetic field generated by the reader | Internal power to transmit signal to the reader |
| Require more powerful readers | Can be effective with less powerful readers |
| Lower data transmission rates | Higher data transmission rates |
| Less tags can be read simultaneously | More tags can be read simultaneously |
| Greater orientation sensitivity | Less orientation sensitivity |
In passive RFID systems the reader sends out electromagnetic waves, and a magnetic field is formed when the signal from the reader "couples" with the tag's antenna. The passive RFID tag draws its power from this magnetic field, and it is this power that enables the tag to send back an identifying response to the query of the RFID reader. When the power to the silicon chip on the tag meets the minimum voltage threshold required to “turn it on,” the tag then can respond to the reader through the same radio frequency (RF) wave. The reader then converts the tag's response into digital data, which the reader then sends on to the information processing system to be used in management applications. Wired Magazine likened passive RFID to a “high-tech version of the children's game ‘Marco Polo'.” In a passive RFID system, the reader sends out a signal on a designated frequency, querying if any tags are present in its read field (the equivalent of yelling out "Marco" in a swimming pool). If a chip is present, the tag takes the radio energy sent-out by the reader to power-it-up and respond with the electronic equivalent of kids yelling “Polo” when they are found.
All of this happens almost instantaneously. In fact, today's RFID readers are capable of reading tags at a rate of up to 1,000 tags per second. Through a process known as “simultaneous identification,” most RFID systems can capture data from many tags within range of the reader's antenna almost simultaneously. In reality however, the tags are responding individually, within milliseconds of one another, in a manner to prevent tag and reader collision in their signals through response protocols.
“Smart labels” are a particularly important form of passive RFID tag. A smart label is an adhesive label that is human and/or machine readable in the manner of a bar code. However, the label is also embedded with an ultra-thin RFID tag "inlay" (the IC and a printed antenna). Smart labels combine the functionality of passive RFID tags with convenience and flexibility. They can either be pre-printed and pre-coded for use or printed “on-demand.” Looking ahead, analysts have predicted that the vast majority of all RFID tags will come in the form of smart labels. In fact, it has been estimated that smart labels will constitute 99.5% of the trillion tags forecast to be in use a decade from now.
An active tag functions in the same manner as its passive counterpart, but it contains a fourth element, an internal battery that continuously powers the tag. As such, the tag is always “on” and transmitting the information contained on its silicon chip. The active tag is only readable, however, when it is in the reading field of an RFID reader. However, the battery significantly boosts the effective operating range of the tag. Thus, while a passive tag can only be read at a range of a few yards, active tags can be read at a distance of 10-30 yards or more. However, while the useful life of an active tag is limited by the life of the on-board battery (typically five years at present), a passive tag has an unlimited life span. Due to the need for a battery, active tags will always cost more and weigh more than a passive tag.
RFID tags can also be classified by their memory capabilities, which can come in three forms:
- Read-only tags: These store data that cannot be changed.
- Read/write tags: These store data that can be altered or even re-written.
- Combination tags: These have some data which is permanently stored on the tag, along with additional memory capacity that is available for updates and/or sensing data.
The EPC is designed to be the unique, item-level identifier for the item to which it is attached. As can be seen in Figure 1, there are four elements that comprise the 96-bit capacity Electronic Product Code. These are:
- The Header (or Version): This section identifies the length of the EPC number including the code type and version in use (up to 8 bits).
- The EPC Manager (or Manufacturer): This section identifies the company or entity responsible for managing the next two EPC elements (up to 28 bits).
- The Object Class (or Product): This section identifies the class of item (for example, the Stock Keeping Unit {SKU} or consumer unit) (up to 24 bits).
- The Serial Number: This section identifies a unique serial number for all items in a given object class (up to 36 bits).
There are literally hundreds of trillions of unique identifications possible in the 96-bit EPC structure, and thus, manufacturers should not have to worry about running out of EPC numbers for unique identifiers for each of their product types for many decades or more. The EPC data structure can generate approximately 33 trillion different unique combinations, which according to projections from the National Research Council's Committee on Radio Frequency Identification Technologies, would allow for each of the billions of people on earth to have billions of tags each. This can be contrasted with the 12-bit structure of the current UPC data structure. As such, there is a “memory” limitation on bar codes, as they can identify only 100,000 products for each of 100,000 manufacturers. Yet, this may simply not be enough for companies operating in the modern global economy.
RFID readers have three essential components: an antenna, a transceiver and a decoder. RFID readers, which are also referred to as interrogators, can differ quite considerably in their complexity, form and price, depending upon the type of tags being supported and the functions to be fulfilled. Readers can be large and fixed, or small hand-held devices. However, the read range for a portable reader will be less than the range that can be achieved using a fixed reader, as the effective read range is determined by the size of the antenna, the efficiency of that antenna, and the power of the transmitter. Readers can have a single antenna, but multiple antennas allow for greater operating range, greater volume/area coverage and random tag orientation. The reader, either continuously (in the case of a fixed-position reader) or on demand (as with a hand-held reader) sends out an electromagnetic wave to inquire if there are any RFID tags present in its active read field. When the reader receives any signal from a tag it passes that information on to the decoding software and processes it for forwarding to the information system it is a part of. Recently, it has been forecast that as soon as 2007, RFID readers will not be just distinct, dedicated devices. Rather, RFID reading capabilities will soon be capable of being integrated into cell phones, PDA's and other electronic devices.
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.