radio frequency identification (rfid) technology
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Radio Frequency Identification (RFID) Technology. Miodrag Bolic Associate Professor School of Information Technology and Engineering University of Ottawa [email protected]. Outline. Introduction to RFID technology EPC Class 1 Generation 2. RFID – Sample Tags / Readers. - PowerPoint PPT PresentationTRANSCRIPT
Radio Frequency Identification (RFID) Technology
Miodrag BolicAssociate ProfessorSchool of Information Technology and EngineeringUniversity of [email protected]
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Outline
Introduction to RFID technology EPC Class 1 Generation 2
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RFID – Sample Tags / Readers
Pallet tag, UHF (Matrics)
Cardboard-case tag, MW (Matrics)
Plastic crate tag, UHF (Rafsec)
Sample Tags Sample Readers
Stationary reader and antenna (Alien)
Signpost activator (Savi)
Stationary reader (Matrics)
Handheld reader (Checkpoint)
Doorway antenna (Checkpoint)
Stationary reader and antenna (SAMSys)
Stationary readers are typically deployed at warehouse portals or loading docks, on conveyor belts or forklift arms, on store shelves, check-out lanes, etc.
Tags can be attached to almost anything: pallets or cases of product vehicles company assets or personnel items such as apparel,
luggage, laundry people, livestock, or pets high value electronics such
as computers, TVs, camcorders
What is RFID? -- The What is RFID? -- The TagsTags
Variations: Memory
Size (16 bits - 512 kBytes +) Read-Only, Read/Write or WORM Type: EEProm, Antifuse
Arbitration (Anti-collision) Ability to read/write one or
many tags at a time Frequency
125KHz - 5.8 GHz Physical Dimensions
Thumbnail to Brick sizes Price ($0.50 to $250)
Are All Tags The Same?Are All Tags The Same?
Tags
Tag separation Types of antennas
Dipole Dual-dipole ...
Material of the antennas: copper, silver, film aluminium, ink
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Reader classification
Mobility Fixed Mobile
stand-alone or card interface
Intelligence Intelligent – program and filter data Nominal – read/write
Interface Wired: TCT, RS232, USB Wireless: WLAN
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Reader classification
Powering method AC Battery DC from the forklift or a track
Reading mode Autonomous Interactive
Triggering device Reducing interference
Connection with external devices PDA, barcode readers, cameras
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Hand-held reader Contain
UHF RFID reader PDA computer that is embedded WiFi, USB and RS232 connectivity, external memory slot bar code scanner very often are sealed IP64 or IP65
Options usually include: GPS Bluetooth Camera module Additional battery 2D bar code scanner Cradle Other readers such as 13.56MHz readers Printing labels
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Protocols
Tag singulation Tree based algorithms Aloha based algorithms
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Software and Integration
From: http://www.infosys.com/rfid/Infosys_White_Paper_on_RFID_Architecture_Strategy.pdf
RFID Architecture
Object Name Service (ONS)• Provides a global, distributed lookup service to translate an
EPC into one URL where further information on the object (XML - metadata) may be found
• Dynamic ONS services record a sequence of custodians as an object moves through a supply chain
• Uses same technology of DNS• Integration and security are key
The Vertical-Based Extendable Mark-Up Language (XML) • XML vocabularies to represent and distribute information
related to objects• Specific functionality data representation for specific
industries
EPC Class 1 Generation 2 UHF protocol Intro and properties Regulatory issues (pages 1-10 TI-RFID UHF
Gen 2) Tag memory organization Reader and tags symbols and coding Packet structure Medium access control States and commands Link timing
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EPC Class I - V
Class V tags Readers. Can power other Class I, II and III tags;
Communicate with Classes IV and V.
Class IV tags: Active tags with
broad-band peer-to-peer communication
Class III tags:semi-passive RFID tags
Class II tags: passive tags with additional
functionality
Class 0/Class I:read-only passive tags
EPC Classes EPCglobal – a joint subsidiary of the Uniform Code
Council and EAN International
UHF Class 1 Gen 2 FeaturesRequirement Gen2 Capability
Global Regulatory Compliance Europe, North America, Japan, etc.
Operation in Noisy Environments Multiple Sessions, Dense Reader Modes
Fast Operation > 1600 tags/sec USA, 600 tags/sec Europe
Privacy Protection EPC code not broadcasted, 32-Bit Kill Password
Improved Accuracy Elimination of “Ghost Reads”, Adaptive Protocols
Memory Write Capability > 7 tag/second write rate, Optional User Memory
Group Searches & Filtering Flexible Select Command
Low Cost Multi-Vendor Availability
Flexibility Tolerates Identical EPC numbers & Multiple EPCs
Certified products Currently Available
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Properties Speed
1500 tags/sec in North America 600 tags/sec in Europe 70ms to write 96-bit EPC
Reliability Adapts to rapidly changing tag populations Including large populations (>1,000 tags) Can identify late-arriving tags immediately
Selection Select command allows flexible tag pre-selection Can select / mask specific tags for identification
Range 8m read range 6m write range
From: EPCglobal. Class 1 Generation 2 UHF Air Interface Protocol Standard Version 1.0.9, 2005.
EPC Class 1 Generation 2 UHF protocol Intro and properties Regulatory issues (pages 1-10 TI-RFID UHF
Gen 2) Tag memory organization Reader and tags symbols and coding Packet structure Medium access control States and commands Link timing
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EPC Class 1 Generation 2 UHF protocol Intro and properties Regulatory issues (pages 1-10 TI-RFID UHF
Gen 2) Tag memory organization Reader and tags symbols and coding Packet structure Medium access control States and commands Link timing
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EPC Data Standards
Electronic Product Code (EPC)Uniquely identifies item in supply chain
96 bit EPC 268 million companies Each with 16 million distinct object classes Each class with 68 billion serial numbers
From: http://java.sun.com/developer/technicalArticles/Ecommerce/rfid/index.html
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Memory Organization
From: EPCglobal. Class 1 Generation 2 UHF Air Interface Protocol Standard Version 1.0.9, 2005.
EPC Class 1 Generation 2 UHF protocol Intro and properties Regulatory issues (pages 1-10 TI-RFID UHF
Gen 2) Tag memory organization Reader and tags symbols and coding Packet structure Medium access control States and commands Link timing
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Reader to tag data link
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OOK coding +ASK
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Pulse interval encoding +ASK
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Spectral mask
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Spectral mask for dense reader operation in alternating 200kHz channals
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PSD for 40kHz data rate
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Tag to Reader Modulation The tag uses Backscatter modulation to respond to a reader. It does
this by switching the reflection coefficient of its antenna (using a shunt
circuit) from a matched load where the incident RF signal is absorbed,
to a short at the antenna terminals where the maximum reflected RF
signal is created. The reader instructs the tag which method of data encoding to use
when sending its data back: Miller Subcarrier encoding FM0 Baseband encoding
The tag can use either/or two modulation formats - the tag
manufacturer selects: ASK (Amplitude Shift Keyed) PSK (Phase Shift Keyed)
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Tag to reader data link
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FM0
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Miller encoding
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Comparison of PSD of FM0 and Miller
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EPC Class 1 Generation 2 UHF protocol Intro and properties Regulatory issues (pages 1-10 TI-RFID UHF
Gen 2) Tag memory organization Reader and tags symbols and coding Packet structure Medium access control States and commands Link timing
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Control frames
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EPC Class 1 Generation 2 UHF protocol Intro and properties Regulatory issues (pages 1-10 TI-RFID UHF Gen 2) Tag memory organization Reader and tags symbols and coding Packet structure Medium access control States and commands (pages 29-46 TI-RFID UHF Gen
2) Link timing
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Class 1 Generation 2 Commands Select Inventory commands
Query QueryAdjust QueryRep ACK NAK
Access commands Req_RN Read Write Kill Lock Access BlockWrite BlockErase
From: EPCglobal. Class 1 Generation 2 UHF Air Interface Protocol Standard Version 1.0.9, 2005.
#2: Tags That Oversleep Fact: Some tags are heavy sleepers Problem: A tag may still be asleep, from being
counted by a prior reader, when it reaches me How do I count it?
Reset
• Late-arriving tags won’t hear the reset
• Multiple resets will interrupt a Query round
Source: Impinj
AB Symmetry Gen2 doesn’t put tags to sleep. It uses a “flag” instead
Flag can be set to “A” or “B”
Count tags from ABA Step 1: Query(A)
Only “A” tags respond “A” tags set their flag to “B” when they are counted
Step 2: Query(B) Only “B” tags respond “B” tags set their flag to “A” when they are counted
Go to step 1
A
B
B
A
After ABA, all tags have been counted and are in A
Source: Impinj
A
B
B
AA
B
B
AA
B
B
A
#3: Reader Interruptions Problem: Handheld reader interrupts a dock-door reader
Don’t want the dock-door reader to lose its ongoing inventory
Solution: Tags have 4 flags rather than just 1 One for each of 4 sessions A reader Queries tags in a single session Different readers can use different sessions
Example Shelf reader uses session #1; handheld reader uses session #2
A
B
B
A
Session 1Session 2
Session 3Session 4
Source: Impinj
EPC Class 1 Generation 2 UHF protocol Intro and properties Regulatory issues (pages 1-10 TI-RFID UHF
Gen 2) Tag memory organization Reader and tags symbols and coding Packet structure States and commands Link timing Medium access control
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Link timing
From: EPCglobal. Class 1 Generation 2 UHF Air Interface Protocol Standard Version 1.0.9, 2005.
EPC Class 1 Generation 2 UHF protocol Intro and properties Regulatory issues (pages 1-10 TI-RFID UHF
Gen 2) Tag memory organization Reader and tags symbols and coding Packet structure Medium access control States and commands Link timing
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Q algorithm
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