ACTIVE RFID DEVICES USING LOCATION &
SIGNAL ANALYSIS (IP BASED)
By Sofoklis Zotos
Cihan Sahin
EE548
Professor Dr. Tulin Mangir
INTRODUCTION
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In this project we will analyze the method of
triangulation and use it to compare the data among
different topographies.
We will optimize AP (access point) location so that
RFID, client and Rogue AP tracking error is minimal.
We will use UWN (Unified Wireless Network) for real
time asset tracking.
Design and develop program for AP location since in
the UWN we have to input the location of the AP’s
ourselves.
OVERVIEW
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RFID’s
Description of Equipment Used
Network diagram
LWAPP
Triangulation and RF fingerprinting
Signal attenuation by distance, formulas
Theoretical values & development
Different topographies, best topography
Results
Videos overview of UWN unified wireless network by Cisco and
net stumbler
References
GENERAL INFO
Almost everything that you buy from retailers
has a UPC bar code printed on it.
 These bar codes help manufacturers and
retailers keep track of inventory, provide
information about quantity and whom the
products are being bought.
 Created in the early 1970s to speed up the
check out process, bar codes have a few
disadvantages.
 Since then companies changed their interest
into smart labels that have read and write
capabilities.
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BARCODES
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Some disadvantages that made the companies
have a change of heart
 In
order to keep up with inventories, companies
must scan each bar code on every box of a
particular product.
 Going through the checkout line involves the same
process of scanning each bar code on each item.
 Bar code is a read-only technology, meaning that it
cannot send out any information.
RFID’S
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Radio Frequency Identification (RFID) is an automatic
identification method, relying on storing and remotely
retrieving data using devices called RFID tags.
An RFID tag is an object that can be attached to a
product, animal, or person for the purpose of
identification using radio waves.
Passive tags require no internal power source.
Active tags require a power source.
PASSIVE
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Passive RFID tags have no internal power supply. The minute
electrical current induced in the antenna by the incoming radio
frequency signal provides just enough power for the CMOS in
the tag to power up and transmit a response.
Most passive tags signal by backscattering.
The response of a passive RFID tag is not necessarily just an ID
number but it can have an EEPROM for storing data.
The lack of an onboard power supply means that the device
can be quite small.
Passive tags have practical read distances ranging from about
10 cm up to a few meters depending on the chosen radio
frequency and antenna size.
ACTIVE
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Unlike passive RFID tags, active RFID tags have their own
internal power source which is used to power any ICs that
generate the outgoing signal.
Active tags are typically much more reliable than passive due to
fewer errors since active tags conduct a "session" with a reader.
Active RFID tags include sensors such as temperature logging,
humidity, shock/vibration, light, radiation, temperature and
atmospherics like ethylene.
Active tags typically have much longer range about 300 feet
and larger storage then passive tags
APPLICATIONS
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Passports
 RFID tags are being embedded in passports issued by many
countries. E-passport
 Contains information of time of entry and exit out of the country
Transport payments
 The city subway of New York is conducting a trial during 2006,
utilizing pay pass with master card as fare payment with
smartcards.
Product Tracking
 High-frequency RFID tags are used in libraries book for tracking,
pallet tracking, building access control, airline baggage tracking
Automotive
 Microwave RFID tags are used in long range access control for
vehicles.
Animal identification
 Implanted RFID tags are also used for animal identification and
future use for people for remote identification
 Bird Flu
TYPES OF RFID TAGS
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RFID tags using RF signals
RFID tags Based on 802.11b technology
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Active and semi-passive only (power supply can
last up to 5 years.
Used for tracking expensive equipment.
Based on Cisco’s wireless unified network.
Does not need to be read from a reader.
Focus will be on this tag.
CISCO UNIFIED WIRELESS NETWORK
Industry’s wired and wireless solution to
address the WLAN security, deployment,
management and control issues.
 Real-time access to business applications such
as RFID’s, Camera systems.
 Thousands of central or remote access points
can be managed from a centralized
management console
 Asset tracking
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EQUIPMENT
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2 AP-10Cisco Unified Wireless
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RFID (802.11b client)Pango, Aeroscout
Windows 2003 Server Enterprise edition running WCS
Cisco Wireless Control System server.
LA-2700 Location Appliance – location purposes and
data storage.
WLC-2600 Wireless Lan Controller – AP controller
Catalyst 3650 POE 24 – Switch
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10AG Access points 2 AP-1131AG AP
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ACTUAL SETUP
NETWORK DIAGRAM
LWAPP: LIGHT WEIGHT ACCESS POINT
PROTOCOL
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Controlling multiple APs.
The server can command a selected group of devices to apply
given setting simultaneously.
LWAPP was proposed by Airespace, as a standard protocol to
provide interoperability among any brand of access point. Its
purpose was to standardize "lightweight" access points with the
Internet Engineering Task Force (IETF), but it was not approved
as a standard.
Location Tracking Approaches
Closest AP
 Triangulation
 RF Fingerprinting
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Cell of Origin
Used in GSM systems.
 Easy and cheap to implement.
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Triangulation – Lateration Techniques
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ToA , TDoA, RSS, AoA
Issues: time synchronization, different environment coefficients
SIGNAL ATTENUATION BY DISTANCE &
FORMULAS
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• PL represents the total path loss experienced between the receiver and
sender in dB.
• PL1meter represents the reference path loss in dB when the receiver-totransmitter distance is 1 meter.
• D represents the distance between the transmitter and receiver in meters.
• n represents the path loss exponent for the environment.
• S represents the degree of shadow fading present in the environment in
dB.
Location Patterning ( Pattern Recognition)
• Calibration Phase
• Operational Phase
This is not a fast solution.
You need to calibrate for
every environment.
RF Fingerprinting
Best solution
 Fast, you can have environment settings ready
to go.
Takes into consideration:
 Reflection
 Attenuation
 Multi-Path
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RF FINGERPRINTING
DIFFERENT TOPOGRAPHIES AND OPTIMIZATION
We will see that different AP deployments will
provide more accurate results.
 There is cases where AP placement should not
be tried at all not only due to location error but
noise that can exist from other AP’s.
 Access points clustered together can result in
poor locationing.
 Improved location accuracy by increasing
density.
 Refrain from straight line placement.
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TOPOGRAPHY 1 (G00D TOPOLOGY)
TOPOGRAPHY 2 (BAD TOPOLOGY)
TOPOGRAPHY 3 (GOOD TOPOLOGY)
TOPOGRAPHY 4 (BAD TOPOLOGY)
BEST TOPOGRAPHY AND CALIBRATION
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Best topography is the one with the less error.
Because location fidelity is statistical, the location
coordinates can be either more or less accurate than
10 meters.
Making adjustments to the deployments of access
points to provide more optimal placement, in addition
to performing a calibration can sometimes yield more
accurate results
The results are very dependent on environment and
deployment.
VIDEOS
& QUESTIONS
REFERENCES
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Wi-Fi Location-Based Services—Design and Deployment Considerations , Copyright ©
2006 Cisco Systems, Inc. All rights reserved.
Release Notes for Cisco Wireless Control System 4.0.87.0 for Windows or
Linux, October 20, 2006
Cisco Unified Wireless Network, Demonstration Document, January 2006
System Demonstrations, Scott Neumann
http://cisco.com/en/US/products/ps6386/prod_technical_reference09186a00805
9ce31.html
http://en.wikipedia.org/wiki/Rfid