WHAT IS RFID?
RFID stands for Radio-Frequency IDentification. The acronym refers to small electronic devices that consist of a small chip and an antenna. The chip typically is capable of carrying 2,000 bytes of data or less.
The RFID device serves the same purpose as a bar code or a magnetic strip on the back of a credit card or ATM card; it provides a unique identifier for that object. And, just as a bar code or magnetic strip must be scanned to get the information, the RFID device must be scanned to retrieve the identifying information.
RFID Works Better Than Barcodes
A significant advantage of RFID devices over the others mentioned above is that the RFID device does not need to be positioned precisely relative to the scanner. We're all familiar with the difficulty that store checkout clerks sometimes have in making sure that a barcode can be read. And obviously, credit cards and ATM cards must be swiped through a special reader.
In contrast, RFID devices will work within a few feet (up to 20 feet for high-frequency devices) of the scanner. For example, you could just put all of your groceries or purchases in a bag, and set the bag on the scanner. It would be able to query all of the RFID devices and total your purchase immediately. (Read a more detailed article on RFID compared to barcodes.)
RFID technology has been available for more than fifty years. It has only been recently that the ability to manufacture the RFID devices has fallen to the point where they can be used as a "throwaway" inventory or control device. Alien Technologies recently sold 500 million RFID tags to Gillette at a cost of about ten cents per tag.
One reason that it has taken so long for RFID to come into common use is the lack of standards in the industry. Most companies invested in RFID technology only use the tags to track items within their control; many of the benefits of RFID come when items are tracked from company to company or from country to country.
Common Problems with RFID
Some common problems with RFID are reader collision and tag collision. Reader collision occurs when the signals from two or more readers overlap. The tag is unable to respond to simultaneous queries. Systems must be carefully set up to avoid this problem. Tag collision occurs when many tags are present in a small area; but since the read time is very fast, it is easier for vendors to develop systems that ensure that tags respond one at a time.
How RFID Works
How does RFID work? A Radio-Frequency IDentification system has three parts:
A scanning antenna
- A transceiver with a decoder to interpret the data
- A transponder - the RFID tag - that has been programmed with information.
The scanning antenna puts out radio-frequency signals in a relatively short range. The RF radiation does two things:
- It provides a means of communicating with the transponder (the RFID tag) AND
- It provides the RFID tag with the energy to communicate (in the case of passive RFID tags).
This is an absolutely key part of the technology; RFID tags do not need to contain batteries, and can therefore remain usable for very long periods of time (maybe decades).
The scanning antennas can be permanently affixed to a surface; handheld antennas are also available. They can take whatever shape you need; for example, you could build them into a door frame to accept data from persons or objects passing through.
When an RFID tag passes through the field of the scanning antenna, it detects the activation signal from the antenna. That "wakes up" the RFID chip, and it transmits the information on its microchip to be picked up by the scanning antenna.
In addition, the RFID tag may be of one of two types. Active RFID tags have their own power source; the advantage of these tags is that the reader can be much farther away and still get the signal. Even though some of these devices are built to have up to a 10 year life span, they have limited life spans. Passive RFID tags, however, do not require batteries, and can be much smaller and have a virtually unlimited life span.
RFID tags can be read in a wide variety of circumstances, where barcodes or other optically read technologies are useless.
- The tag need not be on the surface of the object (and is therefore not subject to wear)
- The read time is typically less than 100 milliseconds
- Large numbers of tags can be read at once rather than item by item.
Problems with RFID
RFID has been implemented in different ways by different manufacturers; global standards are still being worked on. It should be noted that some RFID devices are never meant to leave their network (as in the case of RFID tags used for inventory control within a company). This can cause problems for companies.
Consumers may also have problems with RFID standards. For example, ExxonMobil's SpeedPass system is a proprietary RFID system; if another company wanted to use the convenient SpeedPass (say, at the drive-in window of your favorite fast food restaurant) they would have to pay to access it - an unlikely scenario. On the other hand, if every company had their own "SpeedPass" system, a consumer would need to carry many different devices with them.
RFID systems can be easily disrupted
Since RFID systems make use of the electromagnetic spectrum (like WiFi networks or cellphones), they are relatively easy to jam using energy at the right frequency. Although this would only be an inconvenience for consumers in stores (longer waits at the checkout), it could be disastrous in other environments where RFID is increasingly used, like hospitals or in the military in the field.
Also, active RFID tags (those that use a battery to increase the range of the system) can be repeatedly interrogated to wear the battery down, disrupting the system.
RFID Reader Collision
Reader collision occurs when the signals from two or more readers overlap. The tag is unable to respond to simultaneous queries. Systems must be carefully set up to avoid this problem; many systems use an anti-collision protocol (also called a singulation protocol. Anti-collision protocols enable the tags to take turns in transmitting to a reader. (Learn more about RFID reader collision.)
RFID Tag Collision
Tag collision occurs when many tags are present in a small area; but since the read time is very fast, it is easier for vendors to develop systems that ensure that tags respond one at a time. (Learn more about RFID tag collision.)
Security, privacy and ethics problems with RFID
The following problems with RFID tags and readers have been reported.
The contents of an RFID tag can be read after the item leaves the supply chain
An RFID tag cannot tell the difference between one reader and another. RFID scanners are very portable; RFID tags can be read from a distance, from a few inches to a few yards. This allows anyone to see the contents of your purse or pocket as you walk down the street. Some tags can be turned off when the item has left the supply chain; see zombie RFID tags.
RFID tags are difficult to remove
RFID tags are difficult to for consumers to remove; some are very small (less than a half-millimeter square, and as thin as a sheet of paper) - others may be hidden or embedded inside a product where consumers cannot see them. New technologies allow RFID tags to be "printed" right on a product and may not be removable at all (see Printing RFID Tags With Magic Ink).
RFID tags can be read without your knowledge
Since the tags can be read without being swiped or obviously scanned (as is the case with magnetic strips or barcodes), anyone with an RFID tag reader can read the tags embedded in your clothes and other consumer products without your knowledge. For example, you could be scanned before you enter the store, just to see what you are carrying. You might then be approached by a clerk who knows what you have in your backpack or purse, and can suggest accessories or other items.
RFID tags can be read a greater distances with a high-gain antenna
For various reasons, RFID reader/tag systems are designed so that distance between the tag and the reader is kept to a minimum (see the material on tag collision above). However, a high-gain antenna can be used to read the tags from much further away, leading to privacy problems.
RFID tags with unique serial numbers could be linked to an individual credit card number
At present, the Universal Product Code (UPC) implemented with barcodes allows each product sold in a store to have a unique number that identifies that product. Work is proceeding on a global system of product identification that would allow each individual item to have its own number. When the item is scanned for purchase and is paid for, the RFID tag number for a particular item can be associated with a credit card number.
Are There Concerns About How RFID Will Be Used?
Civil liberties groups (among others) have become increasingly concerned about the use of RFIDs to track the movements of individuals. For example, passports will soon be required to contain some sort of RFID device to speed border crossings. Scanners placed throughout an airport, for example, could track the location of every passport over time, from the moment you left the parking lot to the moment you got on your plane.
In June, the Japanese government passed a draft RFID Privacy Guideline that stated the following:
- Indication that RFID tags exist
- Consumers right of choice regarding reading tags
- Sharing information about social benefits of RFID, etc.
- Issues on linking information on tags and databases that store privacy information.
- Restrictions of information gathering and uses when private information is stored on tags
- Assuring accuracy of information when private information is stored on tags
- Information administrators should be encouraged
- Information sharing and explanation for consumers
There are also concerns about the fact that, even after you leave the store, any RFID devices in the things you buy are still active. This means that a thief could walk past you in the mall and know exactly what you have in your bags, marking you as a potential victim. A thief could even circle your house with an RFID scanner and pull up data on what you have in your house before he robs it.
Military hardware and even clothing make use of RFID tags to help track each item through the supply chain. Some analysts are concerned that, if there are particular items associated with high-level officers, roadside bombs could be set to go off when triggered by an RFID scan of cars going by.
There was a recent report revealing clandestine tests at a Wal-Mart store where RFID tags were inserted in packages of lipstick, with scanners hidden on nearby shelves. When a customer picked up a lipstick and put it in her cart, the movement of the tag was registered by the scanners, which triggered surveillance cameras. This allowed researchers 750 miles away to watch those consumers as they walked through the store, looking for related items.
(Source from science meets fiction )
