1. Radio Frequency Identification (RFID) Technology
Miodrag Bolic
Associate Professor
School of Information Technology and Engineering
University of Ottawa
Radio Frequency Identification (RFID) Technology

2. Outline Introduction to RFID technology EPC Class 1 Generation 2
Radio Frequency Identification (RFID) Technology

3. RFID – Sample Tags / Readers
Sample Readers
Stationary reader and antenna (Alien)
Signpost activator (Savi)
Handheld reader (Checkpoint)
Stationary reader and antenna (SAMSys)
Doorway antenna (Checkpoint)
Pallet tag, UHF (Matrics)
Stationary reader (Matrics)
Plastic crate tag, UHF (Rafsec)
Cardboard-case tag, MW (Matrics)
Stationary readers are typically deployed at warehouse portals or loading docks, on conveyor belts or forklift arms, on store shelves, check-out lanes, etc.
Radio Frequency Identification (RFID) Technology

4. What is RFID? -- The Tags 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

5. Are All Tags The Same? Size (16 bits - 512 kBytes +)
Variations:
Memory
Size (16 bits 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 GHz
Physical Dimensions
Thumbnail to Brick sizes
Price ($0.50 to $250)

6. Tags Tag separation Types of antennas Material of the antennas: Dipole
Dual-dipole
...
Material of the antennas:
copper, silver, film aluminium, ink

7. 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

8. 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

9. Hand-held reader Contain Options usually include: 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

10. Protocols
Tag singulation
Tree based algorithms
Aloha based algorithms

11. Software and Integration
From:
Radio Frequency Identification (RFID) Technology

12. 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

13. 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

14. EPC Classes EPC Class I - V
EPCglobal – a joint subsidiary of the Uniform Code Council and EAN International
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
Radio Frequency Identification (RFID) Technology

15. EPC Standards: Generation 2
Specification recently approved by EPCglobal
Designed to eventually replace Generation 1 standards after a period of testing and transition
Radio Frequency Identification (RFID) Technology

16. UHF Class 1 Gen 2 Features Requirement 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

17. Properties 1500 tags/sec in North America 600 tags/sec in Europe
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.
Radio Frequency Identification (RFID) Technology

18. 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

19. 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

20. EPC Data Standards 96 bit EPC 268 million companies
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
Reference : fid/index.html
From:
Radio Frequency Identification (RFID) Technology

21. Memory Organization
From: EPCglobal. Class 1 Generation 2 UHF Air Interface Protocol Standard Version 1.0.9, 2005.
Radio Frequency Identification (RFID) Technology

22. 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

23. Reader to tag data link

24. OOK coding +ASK

25. Pulse interval encoding +ASK

26. Spectral mask

27. Spectral mask for dense reader operation in alternating 200kHz channals

28. PSD for 40kHz data rate

29. 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)

30. Tag to reader data link

31. FM0

32. Miller encoding

33. Comparison of PSD of FM0 and Miller

34. 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

35. Control frames

36. 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 TI-RFID UHF Gen 2)
Link timing

37. 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.
Radio Frequency Identification (RFID) Technology

38. #2: Tags That Oversleep Reset 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

39. After ABA, all tags have been counted and are in A
AB Symmetry
Gen2 doesn’t put tags to sleep. It uses a “flag” instead
Flag can be set to “A” or “B”
Count tags from ABA
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
After ABA, all tags have been counted and are in A A B B A
Source: Impinj

40. #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
Session 4 A B
Session 3 A B
Session 2 A B
Session 1 A B
Source: Impinj

41. 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

42. Link timing
From: EPCglobal. Class 1 Generation 2 UHF Air Interface Protocol Standard Version 1.0.9, 2005.
Radio Frequency Identification (RFID) Technology

43. 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

45. Q algorithm