KALOMBO NYEMBWE SERGE

L20192E060111

HOMEWORK 6

RFID

1. 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.

2. 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.

3. HISTORY

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. For example 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.

4. Common Problems with RFID

Some common problems with RFID are 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. 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.

5. WORK

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.

In essence, that's how RFID works.

6.   How is RFID used inside a living body?

RFID devices that are intended to be implanted inside a living body (like an animal or human being) have special requirements. They need to be encased in a special kind of casing that will not irritate or react with the living tissues that they are inserted into. The casing must also be transparent to the scanning radio-frequency beam that activates the chip. Some RFID vendors have created biocompatible glass for use in these applications.

One potential problem with being placed within a living organism is that the tiny RFID device may move around under the skin. This can be avoided by using special materials that actually let the surrounding tissue grow up to the casing and bond with it.

Because the radio-frequency waves that activate the microchip containing the identification number are only useful within a few feet (or less), the RFID chip is typically inserted very close to the surface of the skin.

The placement of the device is usually done with a hyperdermic-type needle. This method of insertion also dictates the shape and size of the device; implantable RFID devices are typically the size and diameter of a grain of rice. For dogs, the device is usually implanted between the shoulder blades.

RFID tags have been placed inside cows; some discussion of having all cows implanted with RFID devices has resulted from the recent scare with mad cow disease. Dog owners have used RFID tags to identify their pets rather than tattoos (the more traditional method).

7. Advantages of RFID versus Barcodes

RFID tags and barcodes both carry information about products. However, there are important differences between these two technologies:

• Barcode readers require a direct line of sight to the printed barcode;  RFID readers do not require a direct line of sight to either active RFID tags or passive RFID tags.


• RFID tags can be read at much greater distances; an RFID reader can pull information from a tag at distances up to 300 feet. The range to read a barcode is much less, typically no more than fifteen feet.


• RFID readers can interrogate, or read, RFID tags much faster; read rates of forty or more tags per second are possible. Reading barcodes is much more time-consuming; due to the fact that a direct line of sight is required, if the items are not properly oriented to the reader it may take seconds to read an individual tag. Barcode readers usually take a half-second or more to successfully complete a read.


• Line of sight requirements also limit the ruggedness of barcodes as well as the reusability of barcodes. (Since line of sight is required for barcodes, the printed barcode must be exposed on the outside of the product, where it is subject to greater wear and tear.) RFID tags are typically more rugged, since the electronic components are better protected in a plastic cover. RFID tags can also be implanted within the product itself, guaranteeing greater ruggedness and reusability.


• Barcodes have no read/write capability; that is, you cannot add to the information written on a printed barcode. RFID tags, however, can be read/write devices; the RFID reader can communicate with the tag, and alter as much of the information as the tag design will allow.


• RFID tags are typically more expensive than barcodes, in some cases, much more so.

8. Problems With RFID

RFID problems can be divided into several categories:

• Technical problems with RFID


• Privacy and ethics problems with RFID

• Technical problems with RFID

Problems with RFID Standards

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.

• 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.

• 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;

• 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

• 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. 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.