Transcript
RFID Radio Frequency IDentification
RADAR Technology for Commodity Goods Raj Bridgelall Symbol Technologies January 2004 Disclaimer: This presentation reflects the personal understandings and opinions of the author only and is not intended in any way to convey any position, policy, or opinion of the author’s employer, Symbol Technologies, Inc. The author and Symbol Technologies, Inc. disclaim any liability for any errors or omissions in this paper. Raj Bridgelall
Have You Used RFID Before?
Automated Toll
Mobil Speedpass™ Freedom Pay™
Smart Cards Automotive Security
Retail Security Tags Access Control Raj Bridgelall
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Spectrum of Data-Capture Technologies Manual ID, Short Range, Small Memory
Unattended ID, Long Range, Large Memory Active
Semi-Passive
Functionality
Passive Tags • R/W Memory • Non-Line-of-Sight • Simultaneous ID • Rugged 13.56 MHz <135 kHz
1234 5670
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Battery-based Tags • Much longer range • Location Finding • Larger R/W Memory • Non-Line-of-Sight • Simultaneous ID But ... • Most expensive • Short useful life • Less Rugged
Chip-less Tags • Non-Line-of-Sight • Limited cingulation
1D Barcode • Lowest Cost
~900 MHz
Magnetic Stripe • Durable • Data Hiding 2D Barcode • Larger Data Capacity • Greater Data Integrity
Cost
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Will This Ever Happen?
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RFID Behind The Scenes
Antenna
Integrated Circuit
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Modes, Types, and Classes of RFID Technology E-field Mode Propagation Systems (400 - 900 MHz)
B-Field Mode Inductive Systems (125 kHz & ~13MHz)
λ/4
Tag
Reader
Tag λ/4
Reader Reader: Detects Load Modulation
Tag: Modulates Inductive Coupling
Reader: Detects Changes in Voltage Standing Wave Ratio
Types
Power Communication Cost
Passive
Beam
Backscatter
Semi-passive Battery Backscatter Active Raj Bridgelall
Battery Radiated EM
$0.15 – $0.50 $0.80 - $2 $8 - $75
Tag: Reflects EM
Class 0: Read-Only Class 1: WORM Class 2: Read-Write Class 3: Sensors Class 4: Wireless Nodes 6
How Does Passive RFID Work? Single Tag Communications
Volts
Antenna
RF Coax 0 1 0 0 1 1 0 1 0 Host Electronics
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How Does Passive RFID Work? Multiple Tag Communications Binary Tree Traversal
Antenna
RF Coax
Host Electronics
TDMA
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Tag 1
Tag 2
Tag 3
Tag 4
Tag 5
Tag n
TS: Begin … End TS: Assignment
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How Does Passive RFID Work? Non-Line-of-sight
Antenna
RF Coax
Host Electronics
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Maximum Range for Passive Tags
Volts
Antenna
RF Coax
Host Electronics
Forward Link Limited: Power Transfer
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Passive Tag Range is Forward Link Limited Ps
Reader
Chip Power Consumption Factor
rmax
rmax
λ ≅ 4π
2 Pa ( 1 VL + δ w ) 2 2πCa + (VL + δ w ) Psψ r t AM ηrηc (1 − Rbit t AM ) (2VL + δ w ) Pd
Pr
1 2
Rectifier, ηr
Vd Iant
vp
Vb
La
Vin
Ca
Rm
Antenna, & Matching
Ic
Clamp
ψr
−
Reg
Pa
ηc Cp
ZLogic
Passive Tag IC
Reference: Bridgelall, R., “System Optimization for Passive RF Sensors,” Patent Application, April 2004 Raj Bridgelall
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Power Distribution in a Multipath Environment Power Distribution at 868 MHz
Ceiling
Antenna
Signal Peak
Floor
Signal Cancellation
Palomar, Anu-Leena Annala, et.al. Raj Bridgelall
Peaks (- 3 dBm)
Nulls (- 14.3 dBm)
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Maximum Range for Semi-passive Tags
Antenna
RF Coax
Host Electronics
Backscatter Link Limited: RX Sensitivity
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Semi-Passive Tag Range is Backscatter Link Limited Ps
Reader
ΨT Rsource
rmax en
NB
Pe
kB*To*fr Vin
Rmatch
SNR
LNA
Demodulator
Data Bits
in Noise Figure
Ro
LO
λ 4
Pr
1 1 λ Rbit (r , p e ) = Ps ΨT2ψ r 2( N B −2 ) k B T0 f r 4πr r 1 + R 0
ψr Semi-Passive Tag
BATT
1 2 ln 1 2p e
Receiver sensitivity dominates next
Reference: Bridgelall, R., “Performance Characterization of Active and Passive Protocol Compatible Bluetooth/802.11 RF Tags,” Proceedings of the 6th CDMA International Conference, Seoul, Korea, October 30th, 2001. Raj Bridgelall
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Data Rate (Bits per second)
Semi-Passive Tag Range at UHF and 2.45 GHz Line-of-Sight: 915 MHz
8 1 10
Line-of-Sight: 2.45 GHz
7 1 10 6 1 10 5 1 10 4 1 10 3 1 10 100
Multi-path: 2.45 GHz
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Multi-path: 915 MHz
1 0.1
10
20
30
40
50
60
70
80
90
100
Range (Feet) Reference: Bridgelall, R., “Performance Characterization of Active and Passive Protocol Compatible Bluetooth/802.11 RF Tags,” Proceedings of the 6th CDMA International Conference, Seoul, Korea, October 30th, 2001. Raj Bridgelall
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History of RFID Development 1940
1950
1948 Harry Stockman “Communication By Means of Reflected Power”
1960
1966 Checkpoint & Sensormatic EAS Commercialization 1-bit Electronic Article Surveillance
1950’s D.B. Harris Patents “Radio Transmission Systems with Modulatable Passive Responder”
1940’s RADAR Perfected in WWII Raj Bridgelall
1970
1959 Friend or Foe Military Long Range Transponder
1980
1990
1979 First Implantable RFID for Livestock
1975 Los Alamos Scientific Labs Declassified “Short-range Radio-telemetry for Electronic Identification using Modulated Backscatter”
2000
1996 LA Adopts Pet Tagging
1992 First RFID Toll Collection System in U.S.
1949 – Norman Woodman’s Barcode Concept 1974 – First Barcode Scanned
2003 Mandate
2003
Military Mandate
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RFID Hype Life-cycle Peak of Hype: Failed Pilots Industry Consolidation
Activity
13.56 MHz Technology Widely Available (Poor range, >$1)
ISO-15693
MIT Auto-ID Center (1999)
Supertag™ “Barcode Replacement” Demonstrated.
UHF Available: Tags < 50¢ >10 foot range
1998 Invention Raj Bridgelall
Prototyping
Marketing
Viable Middleware (EPC, ONS, PML, …)
Privacy Issues
Significant Pilots Wal*Mart, DoD, others
2002 2003 Disillusionment
Deployment
Based on a model from The Gartner Group
Time Maturity 17
History of RFID Standardization – Complex International International Electrotechnical Commission (IEC)
International Organization for Standardization (ISO)
International Telecommunications Union (ITU)
ISO/IEC Joint Technical Committee 1 (JTC 1) TC 104 (ISO 10374) Freight Containers TC 204 Road Informatics TC 122 Packaging
SC 17 Smart Cards
ITUITU-T (fka (fka CCITT) Telecommunications ITUITU-R (fka (fka CCIR & IFBR) RadioRadio-frequency Issues
SC 31 Automatic Data Capture
ITUITU-D (fka (fka BDT) Telecommunications Development
Regional Comité Européen Normalisation (CEN) National Standards Australia (SAA)
Comité Européen Normalisation Electrotechnique (CENELEC)
ECMA
British Standards Institute (BSI)
AFNOR
MHI
AIM
Deutches Institut fur Normung (DIN)
ANSI
EIA
UCC
European Telecommunications Standardization Institute (ETSI)
NCITS
IEEE
JISC
Other
Industry Comptia
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ATA
EIA
AIA
HIBCC
AIAG
GTAG
Other
MIT AutoAuto-ID Center
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UCC™ and EAN™ forms EPCglobal™ First End-User Driven Standardization Process in History
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Passive Tag Construction and Cost Projections The UHF ‘Smart Label’ Antenna
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Chip w/ Diode
Markup
(< 10 cents)
(<3 cents)
Package 50
Attach
Die Attach (~ 3 cents)
Price (Cents)
Antenna Chip
40 100’s of Millions
30
20
10
Packaging (~ 4 cents)
100’s of Billions
0 2002
2004
2008
2006
Year Labor + Overhead Extra Based on 50 MU
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Emerging RFID Killer Application Retail Supply Chain Management – Tracking Goods Across Enterprises
Mfg Item
Case
Barcode Source Tagging
Pallets
RFID/Barcode Package Aggregation
Trucks
Distributor
Trucks
Pallets
Portal/Infrastructure Reading (RFID/RTLS) Unattended Auto-ID
Case
Item
RFID Shelf and Hand-Held Reading
Store
User
Barcode/EAS Reading
u The problem = ~$40B/year ♦
Lost goods, wrong delivery, untimely delivery, …
u Costly results according to various studies ♦ ♦ ♦ Raj Bridgelall
15% of shoppers leave without finding an item. $10 billion in goods “lost” during delivery process. 20% of perishables expire before they are sold. 21
Stage I - Pallet and Case Level Tracking Automated Pallet Assembly
Aggregated Pallet Reading
(Barcoded RFID Label)
(Semi-passive or Passive Tags)
Manual Case Verification (Barcode/RFID)
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Automatic Case Verification (Passive Tags)
Container Tracking (GPS, Active Tags)
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Stage II - Item Level Smart Shelves
Minimizing Shrinkage & Counterfeit
Minimizing ‘Out-of-Stock’ Conditions Raj Bridgelall
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Tough Technical Challenges for Immediate Applications (Non-Item Level)
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RFID Portals
False Reads
Good Reads
False Reads
Key Objectives u Eliminate cross-portal reads ♦
Stuff gets on the wrong truck – costly error.
u High throughput ♦
60 - 100 items at fork-lift speeds.
u Robustness of reads ♦ ♦ Raj Bridgelall
Close to 100% of items. Liquids and metals distort field. 25
Tag Detuning and Energy Absorption H2O Dipole Energy Absorption Liquid
0 0
0 0
Reader Antenna
0
Tag Antena
H(ωo,Q) Vb Iant
La
Ca
Rm
Power Transfer
Cparasitic Free-Space Tag Detuned Tag
Operating Frequency
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RFID System Design Considerations Regulatory Layer (Interference/ Public Safety)
Interference
Human Exposure
Far-Field
Near-Field
Compliance
CENELEC/TC211 IEEE/ANSI C95.1 RCR STD-38
Recommendations
Pwr-Up/Active Transmit
SB Radiation
Inter-operability Layer (Standards Driver)
Key
Physical Layer (Cost Driver)
SB Radiation
Modulation Scheme
Operating Frequency
(ASK/PSK/FSK)
Battery
Reader Output Pwr
(Process/Cost)
Time Avg Power
Coding Scheme
Packaging
Antenna Design
IC Design
Protocol/ Architecture
(Cost, E/H Field)
This Determines That Major
Form-Factor Flexibility Performance/ Features Layer (Application Driver)
Minor
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Life/ Reliability
R/W Overall Capacity/ Tag Size Type Pconsumed Pdelivered Read Range
Multi-Tag/ Throughput/ Data Rate
Environmental Compatibility Metals/Water/WLAN
Directionality Uni, Omni
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RFID Transceiver Issues Control ASK MOD
VGA
PA
Data
BPF
Ideal Transceiver Errors
I
Multi-path Reflector antenna VSWR Tx antenna VSWR
0 90
Static reflectors
Q
Moving reflectors Non-coherent Desired Signal
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Multi-Reader Interference
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Interference Throughput For Two RFID Systems Measured Throughput: Interferers are of the same protocol.
Throughput Degradation from Single System
100 90 80 70 60 50 40 Protocol A
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Protocol B
20 10 0 4
5
6
7
8
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10
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Interferer Distance From Tags (Feet) Raj Bridgelall
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Reader/Tag Interference Scenarios Interference Reader IM Products
Reader (Frequency Domain)
AM Modulation (Forward Commands)
CW Interference
AM Modulation Backscatter with AM Modulation Interference
IM Products
Tag RX (Time Domain)
Fast Beats = BER
Slow Beats = “Gap Filling”
Beat Note and Power Cycling
Reader
CW (Backscatter)
Backscatter
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Interferer
CW
Reader is transmitting = OK
Worst Case Fast Beats = BER
Slow Beats = “Gap Filling”
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Summary and Conclusions uRADAR for commodity goods ♦ ♦ ♦
Dominant application in retail supply chain asset tracking Cost declining steadily Standards emerging rapidly
uTough technical challenges remain ♦
Robustness of identification – not 100% accurate yet – Metals and water – Read zone localization – Interference from other RF equipment including other RFID
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Speed of identification in all regulatory environments
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