The EPC System: Ubiquitous Automatic Identification

1

• The EPC SystemUbiquitous Automatic
  Identification
• Sanjay Sarma, MIT

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goals of this talk

• RFID introduction
• Auto-ID Center strategy
• Research here and away

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outline

• RFID and the Auto-ID Center
• A peek at some research issues

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Part I Outline

• What and why of RFID
• The cost issue
• Manufacturing low-cost RFID
• Handling the data
• Current status

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RFID System
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RFID
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RFID Example
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example rfid applications

• Security and Access Control
• Control access to restricted areas, vehicle
  immobilization systems, theft prediction/detection
  
• Supply chain applications
• Asset tracking, reduce out of stocks, reduce
  inventory, reduce bull-whip effect, speed up
  delivery, check freshness, track and trace,
  produce to demand, identify sources of diversion,
  identify counterfeiting, theft prediction, faster
  recalls
• Consumer applications
• Direct order from home, smart appliances, (e.g.
  microwave, washing machine, refrigerator), smart
  healthcare, assisted living
• New and less expected applications
• Customized products, smart recycling,
  checkout-less stores

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outline

• What and why RFID
• The cost issue
• Manufacturing low-cost RFID
• Handling the data
• Current status

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why is rfid expensive today?
increased chip size
greater functionality
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the hypothesis or bet

• Place unique number on tag
• Electronic Product Code, EPC
• 64 bit, 96 bit, and upwards
• Develop manufacturing technology for small chips
  and tags
• Move data on the network
• Network service for resolving EPC
• Network architecture for gathering and routing
  data

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outline

• What and why RFID
• The cost issue
• Manufacturing low-cost RFID in Silicon
• Handling the data
• Current status

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Low cost RFID
 



End
Antenna

Antenna/IC

Conversion

IC


users

Manufacture
Assembly

to Package
Manufacture


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Challenges of IC minimalism

• 0.25 mm2 does it make life tougher?
• ..
• Street width will dominate
• Still have to test the ICs (?)
• Die handling costs are high
• Die-attach/wire-bonding techniques do not scale
• Street width will dominate
• Still have to test the ICs (?)
• Die handling costs are high
• Street width will dominate
• Still have to test the ICs (?)
• Die handling costs are high
• Street width will dominate
• Still have to test the ICs (?)
• Die handling costs are high
• Street width will dominate
• Still have to test the ICs (?)
• Die handling costs are high
• Street width will dominate

15
low cost rfid challenges
 


Antenna

Antenna/IC

Conversion

IC


Manufacture
Assembly

to Package
Manufacture


16
Testing

• Economics today
• 500 - 1000 per wafer
• But minimal functionality means
• High reliability
• Dont test on wafer
• Test wirelessly at conversion

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Slicing and Dicing

• Standard saw-dicing wasteful
• Instead, use separationby thinning

C. Landesberger, S. Scherbaum, G. Schwinn, H.
Spöhrle New Process Scheme for Wafer Thinning
and Stress-free Separation of Ultra Thin ICs,
Proceedings of Microsystems Technologies 2001,
Mesago, Stuttgart, pp. 431-436, 2001.
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low cost rfid challenges
 


Antenna

Antenna/IC

Conversion

IC


Manufacture
Assembly

to Package
Manufacture


1-2
1
1
1
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Antenna

• Screen printing
• Etching
• Forming

M. Feil, C. Adler, G. Klink M. König
Interconnection Techniques for Ultra Thin ICs
and MEMS Elements, Proceedings of Microsystems
Technologies 2001, Mesago, Stuttgart, pp.
437-442, 2001.
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low cost rfid challenges
 


Antenna

Antenna/IC

Conversion

IC


Manufacture
Assembly

to Package
Manufacture


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Assembly

• Fluidic Self Assembly
• Vibratory Assembly
• Pick and place

A. Verma, M. Hadley, H. Yeh and J. Smith
Fluidic Self-Assembly of Silicon
Microstructures, 0569-5503/95/0000-1263, IEEE.
1995.
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vibratory Assembly
Chip Assembly
Chip Design
Antenna Manufacturing
End User
Label / Tag Manufacturing
Wafer Treatment
Label Converting
Inlet Assembly
Silicon Manufacturing
Orientation Check
Courtesy Philips
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vibratory assembly
Chip Assembly
Chip Design
Antenna Manufacturing
End User
Label / Tag Manufacturing
Wafer Treatment
Label Converting
Inlet Assembly
Silicon Manufacturing
Vacuum cylinder
Courtesy Philips
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low cost rfid challenges
 


Antenna

Antenna/IC

Conversion

IC


Manufacture
Assembly

to Package
Manufacture


1-2
1
1
1
25
conversion

• Paper/package/label industry expertise
• Scales well with mass production
• Capital equipment expenditure

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outline

• What and why RFID
• The cost issue
• Manufacturing low-cost RFID
• Handling the data
• Current status

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Architecture Local
Reader
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Architecture Global
Local system
01.203D2A.916E8B.8719BAE03C ????
Local network
Reader
Reader
01.203D2A.916E8B.8719BAE03C
Local database
Quality control specialist
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Inference
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outline

• What and why RFID
• The cost issue
• Manufacturing low-cost RFID
• Handling the data
• Current status

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Status of center

• Research
• RFID/routing software technology MIT Adelaide
• Manufacturing /Control Applications Cambridge
• Standards
• Air-interface between reader and tags
• Software for handling/routing data
• Sponsorship
• 48 sponsors
• 4 continents

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field trial
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outline

• RFID and the Auto-ID Center
• A peek at research issues

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Research Issues

• Tag anti-collision
• Reader anti-collision
• Security and privacy
• Advanced sensor networks
• Data routing and handling
• IC Design
• IC manufacturing
• Silicon processing
• Chip assembly
• Polymers
• Controls/automation
• Manufacturing systems
• System Synthesis
• Supply chain issues

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Anti-collision between tags

• Anti-collision between tags
• Randomized algorithms (Aloha)
• Deterministic tree-walking

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bandwidth
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Preventing reader collision

• Types of reader collision
• Grabbing the same tag
• Interfering with each other

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reader collision problem
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reader collision problem
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3 color tag interference
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4 color frequency interference
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4 color frequency interference
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3 time slots - 2 frequencies
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Functions on the tags

• Write address
• Lock address
• Preload address mask
• Read ID (anti-collision)
• Read payload
• Write payload
• Sleep
• Wake
• Destroy

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Piggyback Sensors
rfid ic

• 01. 203D2A. 916E8B. 8719BAE03C

Payload1
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Piggyback Sensors/Actuators
machine
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event routing

• Considers event
• Processes event
• Reacts to event
• Forwards event

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Savant
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Does protocol compromise privacy?

• Not necessarily. Your choice.
• You can destroy the tag and opt out
• or
• You can keep tag for later use
• (physics is your friend)

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Security for the future issues

• Tags are light-weight
• Anyone can read the tags (promiscuity)
• The same number shows up all the time
• Channel is open

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problem unique and promiscuous

• Personalize the number?
• Tag still identifiable
• However, repeated reads yield same number
• You could still be tracked
• Encrypt the number and contents?
• Contents still secure
• Does not ensure privacy
• Still announces presence

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make tags sullen

• Tags respond to authority
• Tag has built-in key
• Reader broadcasts key
• Tag recognizes trusted reader, responds
• Perhaps the key can be personalized
• Problems
• Control of keys at an enterprise level always
  problematic
• How do you pass the key to the individual?
• Brittle system
• WPS Someone else takes over your tags

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changing numbers

• Tag puts out a different number each time
• Shared secret permits user to infer the number
• Challenge
• Number must still be unique
• Pros
• Privacy ensured
• Tags cannot be secreted (our tags still
  talkative)
• Cons
• Still some shared secret who owns it?
• Counterfeit not prevented (use time (nonce?))

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Re-programming the tag

• Problems
• Air interface always vulnerable
• Grey area of ownership in retail
• Solutions
• Physical contact for reprogramming
• Physical contact reset of memory
• (Resurrected Duckling, University of Cambridge)

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mass hijack of tags

• Could happen in destroy or re-programming
• Physics our friend
• Bandwidth limited 200 tags a second
  anti-collision
• Destroy must be individually addressed
• So it takes time to kill
• Surveillance

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conclusions

• A large system
• with many components
• which must co-exist
• and be scalable
• Many juicy problems
• await beyond Occums razor

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Fin
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Research Issues

• Tag anti-collision
• Reader anti-collision
• Security and privacy
• Advanced sensor networks
• Data routing and handling
• IC Design, RF power generation
• IC manufacturing
• Silicon processing
• Chip assembly
• Polymers
• Controls/automation
• Manufacturing systems
• System Synthesis
• Supply chain issues

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reader to tag modulation
On Off Keying (OOK), Min 90 Modulation Depth
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Modulation reader to tag
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tag to reader

• Bit Cell Time 8 µs Tag to Reader (128 kbs)
• 2 Transitions 0
• 4 Transitions 1
• Always Transitions Within a Bit

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Anti-collision

• A Reader Talks First (RTF) System
• Commands Issued from Reader
• Tags Reply at a Later Time While Reader Listens
• Transactions are Self-Contained Operations
  (Minimal Persistent State Information Required)

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Contention Detection

• Anti-Collision Algorithm Relies on Detecting
  Contention (When More than One Tag is Responding
  to a Reader Command).

Contention- Two Tags, Same Clock Rate, 1-Bit
Difference
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Anti-Collision Algorithm
First Three Bits of Tag Address Space as a Binary
Tree
CMD 00001000 (Ping) PTR 00000000 LEN
00000000 (0) VALUE 0
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Anti-Collision
CMD 00001000 (Ping) PTR 00000000 LEN
00000000 (0) VALUE 0
CMD 00001000 (Ping) PTR 00000000 LEN
00000011 (3) VALUE 011
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outline

• RFID and the Auto-ID Center
• A peek at the protocol
• Security issues
• Discussions with David Brock, Joe Foley, Dan
  Engels, Peter Cole, Ron Rivest

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Research Issues

• Tag anti-collision
• Reader anti-collision
• Security and privacy
• Advanced sensor networks
• Data routing and handling
• IC Design
• IC manufacturing
• Silicon processing
• Chip assembly
• Polymers
• Controls/automation
• Manufacturing systems
• System Synthesis
• Supply chain issues