This presentation gives a brief explanation of the toll collection used by governments to collect toll tax all across the world. And also explains the usage of the RFID (Radio Frequency Identification) system. Demerits of the RFID toll collection system.
2. TABLE OF CONTENTS
o What is RFID?
o Why we use RFID?
o What is inside this RFID system?
o Different types of RFID tags.
o What does the RFID reader consists of?
o What are the components present in the RFID
tags?
o Frequency of operation
o Applications
o How does the toll system work?
o Demerits
o Reference links and videos
RFID TAG
3. What is RFID?
RFID – Radio Frequency Identification
So this technology which is working
on radio frequency or radio waves.
Which is used to automatically
identify the objects or tracking the
objects.
RFID system
4. It is same like barcode scanner/reader technology but it should
be in the “line-of-sight” of the reader, which is not required in
case of RFID technology.
So, as far as this object is within the range of the reader, object
is able to identify the reader and it is able to send the feedback
signal back to the reader.
So using this RFID technology we can track your multiple objects
at the same time.
5. Why we use RFID
These are the reasons why we use RFID over NFC & BARCODE technology:
Can identify individual objects without direct line of sight.
Can scan items from inches to feet away, depending on type of tag and reader.
Data can be updated in real time.
Read time is less than 100 milliseconds per tag.
Range up to 100 m.
Continuous sampling.
Bit rate & Power rate varies with frequencies.
6. what is inside RFID system?
RFID SYSTEM
RFID TAG RFID READER
Active tag
Passive tag
Semi-Passive tag
7. Active tag
While in case of an active tech they used to have their own
power supply.
But for transmitting the signal back to the reader, also they are
relying on their own power supply.
A Passive Reader Active Tag (PRAT) system has a passive reader
which only receives radio signals from active tags (battery
operated, transmit only).
The reception range of a PRAT system reader can be adjusted
from 1–2,000 feet (0–600 m), allowing flexibility in applications
such as asset protection and supervision.
8. Passive tag
Now this passive tags do not have their own
power supply.
So this passive tag relies on the radio waves
which is coming from the RFID reader for the
source of energy.
It is also called as an Active Reader Passive
Tag (ARPT).
Range is less.
9. Semi-passive tag
Semi-passive tags are based on the same
principle as passive tags but include battery
that helps to extend the communication range,
tag memory and in some cases include sensors.
But for transmitting the feedback signal back
to the RFID reader, they used to rely on the
signal which is coming from the RFID reader.
Also called Semi-active or Battery-assisted
Passive (BAP) tags.
Semi-passive tag
10. What does the RFID reader consists
of?
Today RFID readers are coming in many size
and shapes.
RFID reader could be a handheld reader or it
could be as large as the size of the door
which you normally see inside the shopping
malls.
This RFID reader mainly consists of three
components:
RF signal generator
Microcontroller
Receiver signal detector
RFID reader
11. o RF signal generator:
o Receiver signal detector:
o Microcontroller:
So this signal generator generates a
radio wave which are transmitted using
this antenna. Also to receive the
feedback signal which is coming from the
tag.
The RFID reader also has a receiver or a
signal detector and to process the
information which has been sent by the
RFID tag.
This RFID reader also have a microcontroller or
many times this RFID reader is directly connected
to the computer.
12.
13. What are the components present
in the RFID tags?
So most of the tags which are being used today are passive tags
because these passive tags are quite cheaper compared to the
active tags as well as they do not require any power source.
This RFID tag mainly consists of four components:
→ Transponder
→ Rectifier circuit
→ Controller
→ Memory element (chip)
14. o Transponder :
o Rectifier circuit :
o Memory element :
It receives the radio waves which are
coming from the reader and sends the
feedback signal back to the reader.
As the passive Tags do not have their own
supply, so they rely on the energy from radio
waves which are coming from the reader.
So using this rectifier circuit, the energy that
is coming from the radio waves is stored
across the capacitor.
It stores the details of the vehicle and
owner details of the tag.
15. Frequency of operation
Types of frequencies
Low frequency (LF)
125KHz (or) 134KHz
High frequency (HF)
13.56 MHz
Ultra high frequency (UHF)
860-960 MHz
Range up to 10 cm Range up to 1 m Range 10 – 15 m
16. Working principle
Now this working principle also depends upon the frequency
of operation.
So for the low frequency (LF) and the high frequency
operation (HF), the working principle is based on the
inductive coupling (Near field coupling).
While in case of a ultra high frequency (UHF), the working
principle is based on the electromagnetic coupling.
17. Inductive coupling
So the field which is generated by this RFID reader used to get coupling
with the antenna of a RFID tag.
And because of this mutual coupling the voltage will get induced across
the coil of RFID tag.
Now the sum portion of this voltage is getting rectified and used as a
power supply for the controller as well as the memory elements.
Now as the RFID reader is sending a radio waves of a particular
frequency, so the voltage that is induced across the coil is also of a
particular frequency.
19. Electromagnetic coupling
So in case of ultra high frequency as a distance between the reader
and the tag is up to a few meters.
So the coupling between the reader and the coil will be the far field
coupling.
So this RFID reader continuously sending the radio waves of a
particular frequency towards the tag and in response, this tag is
sending a weak signal to the RFID reader.
Now this weak signal which is being sent back to the RFID reader is
known as the backscattered signal and the intensity of this
backscattered signal depends upon the load matching across this coil.
22. Demerits
Tag collision: Tag collision occurs when too many tags confuse an
RFID reader by transmitting data at the same time. Choosing a
reader that gathers tag info one at a time will prevent this issue.
Reader collision: Reader collision, when a signal from one RFID
reader interferes with a second reader, can be prevented by using
an anti-collision protocol to make RFID tags take turns
transmitting to their appropriate reader.
Materials like metal & liquid can impact signal.
Sometimes not as accurate or reliable as barcode scanners.
Cost – RFID readers can be 10x more expensive than barcode
readers.
Implementation can be difficult & time consuming.
23. Toll collection system
o As the vehicle enters the FASTag line, the reader present at the
top of the rod reads the FASTag which is present on the
windshield of the vehicle.
o All the information of the tag is sent to the acquirer bank from
the toll system.
o To check whether the tag is valid or not the bank sends the tag
details to the NETC mapper.
o NETC (National Electronic Toll Collection ) mapper is a digital
library which stores the FASTags issued till now.
o Now, the NETC mapper tells the acquirer bank whether the tag is
valid or not.
25. o If the card is invalid the acquirer bank sends the invalid message
to the toll plaza.
o Otherwise if the card is valid and has low balance than the
indicated toll price it shows the message as BLACKLISTED.
o If the card is valid the acquirer bank sends the amount that
should be debited, to the NETC mapper which is forwarded to the
issuer bank
o The money will be debited from the vehicle owner/FASTag owner
and the conformation message is sent to the toll plaza.
27. Reference books
RFID Handbook: Fundamentals and Applications in Contactless -
Klaus Finkenzeller · 2010
Design and Optimization of Passive UHF RFID Systems - Jari-
Pascal Curty, Michel Declercq, Catherine Dehollain · 2006
RFID Implementation - Dennis Brown · 2007