1.Introduction
Radio frequency identification (RFID) is a rapidly growing technology that has the potential to make great economic impacts on many industries. While RFID is a relatively old
technology, more recent advancements in chip manufacturing technology are making RFID
practical for new applications and settings, particularly consumer item level tagging. These
advancements have the potential to revolutionize supply-chain management, inventory
control, and logistics. At its most basic, RFID systems consist of small transponders, or tags, attached to physical objects. RFID tags may soon become the most pervasive microchip in history. When wirelessly interrogated by RFID transceivers, or readers, tags respond with some identifying information that may be associated with arbitrary data records. Thus, RFID systems are one type of automatic identification system, similar to optical bar codes.
There are many kinds of RFID systems used in different applications and settings. These
systems have different power sources, operating frequencies, and functionalities. The
properties and regulatory restrictions of a particular RFID system will determine its
manufacturing costs, physical specifications, and performance. Some of the most familiar
RFID applications are item-level tagging with electronic product codes, proximity cards for
physical access control, and contact-less payment systems. Many more applications will
become economical in the coming years.
While RFID adoption yields many efficiency benefits, it still faces several hurdles. Besides
the typical implementation challenges faced in any information technology system and
economic barriers, there are major concerns over security and privacy in RFID systems.
Without proper protection, RFID systems could create new threats to both corporate
security and personal privacy.
In this section, we present a brief history of RFID and automatic identification systems. We
summarize several major applications of RFID in Section 2. In Section 3, we present a
primer on basic RFID principles and discuss the taxonomy of various RFID systems.
Section 4 addresses the technical, economic, security, and privacy challenges facing RFID
adoption. Finally, Section 5 briefly discusses emerging technologies relevant to RFID.
1.1 RFID Origins
The origins of RFID technology lie in the 19th century when luminaries of that era made
great scientific advances in electromagnetism. Of particular relevance to RFID are Michael
Faraday’s discovery of electronic inductance, James Clerk Maxwell’s formulation of
equations describing electromagnetism, and Heinrich Rudolf Hertz’s experiments validating
Faraday and Maxwell’s predictions. Their discoveries laid the foundation for modern radio
communications.
Precursors to automatic radio frequency identification systems were automatic object detection
systems. One of the earliest patents for such a system was a radio transmitter for object
detection system designed by John Logie Baird in 1926 [4]. More well known is Robert
Watson-Watt’s 1935 patent for a “Radio Detection and Ranging” system, or RADAR. The
passive communication technology often used in RFID was first presented in Henry
Stockman’s seminal paper “Communication by Means of Reflected Power” in 1948 [23].
One of the first applications of a radio frequency identification system was in “Identify
Friend or Foe” (IFF) systems deployed by the British Royal Air Force during World War II 0.
IFF allowed radar operators and pilots to automatically distinguish friendly aircraft from
enemies via RF signals. IFF systems helped prevent “friendly fire” incidents and aided in
intercepting enemy aircraft. Advanced IFF systems are used today in aircraft and munitions,
although much of the technology remains classified.
Electronic detection, as opposed to identification, has a long history of commercial use. By
the mid- to late-1960s, Electronic Article Surveillance (EAS) systems were commercially
offered by several companies, including Checkpoint Systems and Sensormatic. These EAS
systems typically consisted of a magnetic device embedded in a commercial product and
would be deactivated or removed when an item was purchased. The presence of an activated
tag passing through an entry portal would trigger an alarm. These types of systems are often
used in libraries, music stores, or clothing stores. Unlike RFID, these types of EAS systems
do not automatically identify a particular tag; they just detect its presence.
1.2 Auto-Identification and RFID
In terms of commercial applications, RFID systems may be considered an instance of a
broader class of automatic identification (auto-ID) systems. Auto-ID systems essentially
attach a name or identifier to a physical object by some means that may be automatically
read. This identifier may be represented optically, electromagnetically, or even chemically.
Perhaps the most successful and well-known auto-ID system is the Universal Product Code
(UPC). The UPC is a one-dimensional, optical barcode encoding product and brand
information. UPC labels can be found on most consumer products in the United States.
Similar systems are deployed worldwide. The Uniform Code Council (UCC), a standards body originally formed by members of the grocery manufacturing and food distribution industries, originally specified the UPC [25]. A precursor body to the UCC first met in 1969 to discuss the need for an inter-industry auto-ID system. By 1973, a one-dimensional (or linear) barcode design was chosen. In 1974, a supermarket in Ohio scanned the first UPC-labeled product: a package of Wrigley’s gum. Adoption of the UPC grew steadily throughout the following years, to the point where UPC barcode scanners are found in a vast majority of large American retailers. Today, over five billion barcodes are scanned around the world each day. Shipping and transit companies, such as United Parcel Service, Federal Express, and the United States Postal service, commonly use two-dimensional barcodes, which can carry more data in a smaller surface area.
Optical barcodes offer faster, more reliable, and more convenient inventory control and
consumer checkout than checking out by hand. Several weaknesses of optical barcodes are
that they require line-of-sight and may be smudged or obscured by packaging. In most
circumstances, optical barcodes still require some human manipulation to align a barcode
label with a reader. Supermarket shoppers have certainly experienced a checker struggling to
scan an optical barcode. Auto-ID systems that transmit data via RF signals, i.e. RFID, do not have the same performance limitations as optical systems. Data may be read without line-of-sight and without human or mechanical intervention. A key advantage in RF-based auto-ID systems is parallelism. Modern RFID systems may offer read rates of hundreds of items per second.