Radio Frequency Identification (RFID) Technology Miodrag Bolic Associate Professor School of Information Technology and Engineering University of Ottawa mbolic@site.uottawa.ca Radio Frequency Identification (RFID) Technology

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

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

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

Are All Tags The Same? Size (16 bits - 512 kBytes +) 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)

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

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

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

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

Protocols Tag singulation Tree based algorithms Aloha based algorithms

Software and Integration From: http://www.infosys.com/rfid/Infosys_White_Paper_on_RFID_Architecture_Strategy.pdf Radio Frequency Identification (RFID) Technology

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

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

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

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

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

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

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

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 : http://java.sun.com/developer/technicalArticles/Ecommerce/r fid/index.html From: http://java.sun.com/developer/technicalArticles/Ecommerce/rfid/index.html Radio Frequency Identification (RFID) Technology

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

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

Reader to tag data link

OOK coding +ASK

Pulse interval encoding +ASK

Spectral mask

Spectral mask for dense reader operation in alternating 200kHz channals

PSD for 40kHz data rate

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)

Tag to reader data link

FM0

Miller encoding

Comparison of PSD of FM0 and Miller

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

Control frames

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

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

#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

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

#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

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

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

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

Q algorithm