Radio Frequency Identification
(RFID)
Presenter: Dusan Stevanovic
April 3, 2007
Introduction
RFID are systems that transmit identity (in
the form of a unique serial number) of an
object or person wirelessly, using radio
waves.
RFID is a subset of Auto-ID technologies such
as barcodes, optical card readers and some
biometric technologies
Next wave: Allows objects to be connected to
the Internet
Introduction
Basic RFID technology consists of
a reader and RFID tag
Reader is a device that has one
or more antennas that emit radio
waves and receive signals back
from the tag
RFID tag consists of a microchip
attached to a radio antenna
mounted on an underlying layer
Introduction
Perceived Advantages of RFID:
Non-line-of-sight (possibly built into or placed
inside containers)
Long range
Many tags read out at once
Robust (not as fragile as a printed bar code)
Gives a path from simple identification of objects
to locating objects
Almost as cheap as a printed bar code! (Almost….)
Outline
Brief history of RFID technology
How RFID technology works and description
of different types of RFIDs
RFID Standards
RFID Business Applications
Privacy and Security Issues in RFID
History of RFID technology
First application to identify planes in World
War II using radar
60’s - Electronic article surveillance (EAS)
used to identify whether an item has been
paid or not using a 1-bit tag
80’s first automated toll payment systems
History of RFID technology
Early 90’s – IBM developed UHF RFID
systems with better range (up to 20 feet
under good conditions) and faster data
transfer
Auto-ID Center established at MIT in 1999
Developed first low-cost RFID applications
Developed 2 air interface protocols and
Electronic Product Code (EPC) numbering
scheme
EPC technology is to be adopted by
retailers such as Wal-Mart and Target
How RFID technology works?
Active vs. Passive tags
2 main categories of RFID systems: passive and active tags
Active RFID systems:
Active tags have their own transmitter and power source
Write-once or rewritable
Broadcast a signal to transmit the data stored on the microchip using a
power source (battery, sunlight)
Operate at 455 MHz, 2.45 GHz, or 5.8 GHz
Long read range of 20 meters to 100 meters
Expensive – 10$ – 50$ per tag
Passive RFID systems:
Do not have a transmitter or power source
Write-once or rewritable
Reflect back radio waves coming from the reader antenna
Operate at LF, HF and UHF
Short read range of few centimeters to 10 meters
Cheap – 20¢ – 40¢ per tag
How RFID technology works?
Semi-Passive (Active) tags
Semi-Passive RFID tags
Use a battery to run the chip’s circuitry,
but communicate by drawing power from
the reader
Usually sleep until they are woken up by a
signal from the reader, which conserves
battery life
Write-once or re-writable
How RFID technology works?
Inductive Coupling in Passive tags
Used in low and high
frequency tags
A coil in the reader
antenna and a coil in
the tag antenna form an
electromagnetic field
Tag draws power from
the field, uses power to
run its circuitry and
changes the electric
load on the antenna
Tags pass information
by releasing energy
from the capacitor to
the tag coils in varying
strengths over time,
which affects the radio
frequency emitted by
the tag.
The reader antenna
senses the change in
the magnetic field and
converts these changes
into the ones and zeros
that computers
understand.
How RFID technology works?
Backscatter in Passive tags
Also called Propagation coupling
Used by UHF passive systems
No electromagnetic field is formed
Instead, the tag gathers energy from the reader antenna, and the
microchip uses the energy to change the load on the antenna and
reflect back an altered signal.
Modulation is accomplished by varying RF input impedance between 2
different states
To send data from the tag to the reader, the amplitude, phase or
frequency shift keying is applied
How RFID technology works?
Factors affecting Performance
Inductive coupling has a reader field of smaller size than
Backscattering method
Backscattering is harder to control, because waves travel longer
distances and can be received by the wrong tags
Low frequency tags are ideal for applications where tag needs to be
read through material or water at close range
Usually operate in 124 KHz – 135 KHz
High and Ultra-High frequency tags offer farther read range but do
not penetrate water or materials as well
How RFID technology works?
Factors affecting Performance
Detuning the antenna
With backscatter, the antenna is tuned to receive waves of
particular frequency
When an antenna is placed on an object or product packaging that
is not "RF friendly," the antenna can be detuned
Signal attenuation (Path Loss)
A tag’s reflected signal decreases as the inverse fourth power of
the distance between tag and reader
In other words, the signal emitted by the reader attenuates natural
with distance, and the signal reflected by a passive tag attenuates
at a much faster rate.
RFID Standards
Several RFID standards exist:
Identification, coding of unique item identifiers, or other data on the RF tag
Data and system protocols, effectively the middleware of an RFID system
The air interface, that is, the wireless communication between the reader
and the tag
Defines anti-collision schemes between a reader and tags such as pure
and slotted ALOHA
Defines network layers in RFID systems
Application support, which provides advice about how to implement the
technology
Examples:
ISO 14443 (for contact-less systems), ISO 15693 (for vicinity systems, such
as ID badges), and ISO 18000 (to specify the air interface for a variety of
RFID applications).
EPCglobal has developed widely accepted standards and one of them is EPC
standard, used for product identification
RFID Standards
RFID Standards
EPC Standard
A serial, EPC code, created by the Auto-ID Center, which will complement barcodes
EPCglobal has developed a Object Naming Service (ONS) system that is similar to the Domain Name
Service (DNS) used on the Internet.
ONS acts as a directory service for organizations wishing to look up product numbers (also known as
EPC numbers) on the Internet.
EPC has digits to identify the manufacturer, product category and the individual item.
Generation 1 EPC tags protected by an 8-bit password and no key-management, pure ALOHA
Generation 2 EPC tags require longer passwords and uses slotted ALOHA
RFID Standards
EPC™ Radio-Frequency Identity Protocols
Class-1 Generation-2 UHF RFID – January 2005
Protocol for Communications at 860 MHz – 960 MHz
Physical layer
Defines modulation between the reader and tag and vice versa
Defines which shift keying modulation should tags and readers support
Tag-identification layer
3 operations: Select, Inventory, Access
Select – selection of a specific Tag population
Inventory – identification of tags in a particular tag population
Access – communication with (reading from and/or writing to) a Tag after
Inventory command
Protocol (MAC) parameters for R->T and T->R
Data encoding
Data rates
Frame synchronization for Slotted-ALOHA
Frequency-hopping spread-spectrum in multiple reader environments
Channel width 500 kHz
Tag memory – reserved, EPC, TID memory to identify which commands tag
supports and user (rewritable) memory
defines formats of kill password, access password, EPC code
RFID Business Applications
RFID Network
RFID networks are usually deployed on top of Enterprise networks
Enterprise network: application servers, databases, switches, clients
RFID network: RFID readers, RFID client applications and
middleware
Network-centric design
RFID middleware between RFID readers and Enterprise/RFID applications
Middleware
Manages readers’ hardware
Process/Filters data from the readers
Between client applications and readers
Providing enterprise wide APIs on which end-users can build
software applications
RFID Business Applications
RFID Network
Piggyback Design
RFID network connected
directly to available ports
on edge switches
Pros: low-cost
Drawbacks: scalability
limited, vulnerable to high
traffic load
Dedicated Design
RFID readers connected
to the dedicated switches
Separated from enterprise
network
Pros: greater scalability
and resiliency, traffic load
handled by M/W
Drawbacks: more
expensive
RFID Business Applications
Supply chain management
RFID tags are used to track products throughout the
supply chain
Replacement for the bar code scanners
Efficiency
line-of-sight access to read the tag no longer
necessary
Simultaneous reading of multiple RFID tags
Read range of RFID is larger
Smart shelves
Placing RFID readers on store shelves
Automated just-in-time product shipments
RFID Business Applications
Mobile RFID
Mobile phone as RFID
reader
Integration of RFID and
wireless sensor network
infrastructure with mobile
communication and
wireless internet
Uses:
Making a reservation as
simple as holding the phone
close to advertising billboard
Purchasing movie tickets
Privacy/Security concerns
Privacy and Security Issues in
RFID
Unauthorized and anonymous readings of
tags
Privacy concerns including location tracking
and customer buying habits
Solutions: “kill switches”, sleeping tags,
tag passwords, encryption and tag blocking
Security concerns including credit card and
other ID information theft
Solutions: authenticate readers using ID
numbers stored in tags’ memory
References
1.
Roberti. Mark, 2007. What is RFID? [online]. Available from:
http://www.rfidjournal.com/article/articleview/1339/1/129/. [March 17th 2007].
2.
Roberti. Mark, 2007. The History of RFID Technology? [online]. Available from:
http://www.rfidjournal.com/article/articleview/1338/1/129/. [March 17th 2007].
3.
Roberti. Mark, 2007. The Basics of RFID Technology? [online]. Available from:
http://www.rfidjournal.com/article/articleview/1337/1/129/. [March 17th 2007].
4.
Landt, J. 2005. The History of RFID. IEEE POTENTIALS. 0278-6648. 8-12.
5.
6.
Weinstein, R., 2005. RFID: A Technical Overview and Its Application to the Enterprise. IT Pro. 1520-9202. 27-33.
Roussos, G., 2006. Enabling RFID in Retail. The 31st IEEE Conference on Local Computer Networks, Tampa, Florida –
November 14-17, 2006. IEEE Computer Society. 25-30.
7.
Phillips, T., Karygiannis, T., Kuhn, R., 2005. Security Standards for the RFID Market. Emerging Standards. IEEE
Computer Society. 1540-7993. 85-89.
8.
Lee, H., Kim, J., 2006. Privacy threats and issues in mobile RFID. Proceedings of the First International Conference on
Availability, Reliability and Security. Vienna, Austria – April 20-22, 2006. IEEE Computer Society.
9.
Zhao, Y.Z., Gan, O.P., 2006. Distributed Design of RFID Network for Large-Scale RFID Deployment. International IEEE
Conference on Industrial Informatics. Singapore – August 16-18, 2006. IEEE. 44-49.
10. EPC™ Radio-Frequency Identity Protocols. Class-1 Generation-2 UHF RFID Protocol for Communications at 860 MHz–
960 MHz Version 1.0.9 [online]. Available from:
http://www.epcglobalinc.org/standards/Class_1_Generation_2_UHF_Air_Interface_Protocol_Standard_Version_1.0.9.pd
f