U H F b a n d ( 8 6 0 - 9 6 0 M H z ) R F I D - - PowerPoint PPT Presentation

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U H F b a n d ( 8 6 U H F b a n d ( 8 6

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6 M H z ) R F I D 9 6 M H z ) R F I D d e v e l

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Jin Mitsugi Auto-ID Labs. Japan Keio University

APRICOT 2005, Feb. 21, 2005

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A g e n d a A g e n d a

• Features of UHF band RFID system
• Long range communication
• Multiple tag reading
• What deteriorates the reading accuracy？
• Radio Regulations around UHF band

RFID system

• Radio regulations?
• Japan status

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E x e c u t i v e s u m m a r y E x e c u t i v e s u m m a r y

• UHF band RFID features 5-10m reading
• distance. Primary target is supply chain

management.

• Reading accuracy depends on the radio

propagation environment as well as tag and reader performance.

• 952-954MHz band will be opened to

RFID system in Japan from early FY.2005.

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UHF band? UHF band?

VHF UHF SHF 30MHz 300MHz 3GHz 30GHz TV ch.1 = 90-96MHz TV ch.12 = 216-222MHz UHF TV 470-770MHz Cellular Phone etc. 810-960MHz HF 3MHz 2.45GHz RFID 860-960MHz RFID 13.56MHz RFID Frequently referred to as UHF RFID Satellite Broadcasting 12GHz

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Typical Usages of UHF RFID Typical Usages of UHF RFID

Interrogator

Low power type Low power type High power type High power type

Folk Lift Top view Side view Interrogator Antenna Long range, multiple tags reading Short range, individual tag reading

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C l a s s

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R F I D R F I Ds y s t e m s y s t e m

• Active RFID:
• carries battery for radio wave transmission
• Passive RFID
• Passive backscatter: Power is supplied by

interrogator in the form of radio wave.

• Read only
• Read/Write
• may carry battery to power the logic circuit in tag

(semi-passive).

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Basics of UHF passive RFID Basics of UHF passive RFID

Interrogator Antenna Tag Antenna Logic circuit Network Command/ Power supply Response

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Interrogator Interrogator – – Tag communication Tag communication in a nutshell in a nutshell

Interrogator Tag Power supply and wake up tag Command Reply Power supply

Power shall be supplied to tags by interrogator Power shall be supplied to tags by interrogator while tags reply. while tags reply.

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Power level chart Power level chart

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Power(dBW) Interrogator Output power Tag reply power Interrogator reception Path loss Path loss

90dB down = 1/1000,000,000

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F u n d a m e n t a l d i l e m m a

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p a s s i v e F u n d a m e n t a l d i l e m m a

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p a s s i v e Ｒ Ｆ Ｉ Ｄ Ｒ Ｆ Ｉ Ｄ

• Tag needs to efficiently absorb the radio

wave energy from interrogator.

• Tag needs to reflect the radio wave,

generating 1 and 0 states, for the reply.

Solutions ・ Optimal design of tag impedance ・ Separate antennas for power supply and communications

Absorb ? Reflect?

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W h a t i s t h e p u r p

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e

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U H F R F I D ? W h a t i s t h e p u r p

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e

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U H F R F I D ?

Retailor Distribution Center Factory Expiry / Overstock Counterfeit Theft Accurate and real-time visibility of total supply chain by RFID

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W h y U H F ? W h y U H F ?

• Long range communications requirement

Several meters reading range required

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W h y U H F ? ( 2 ) W h y U H F ? ( 2 )

( )

⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ = π λ π 4 4 1

2 2 t r r t

G L P G P

Power reception at tag Transmitting power Wavelength Path loss The lower the frequency, the larger the power reception. The lower the frequency, the larger the tags becomes. Good compromise = UHF band; Same story as cellular phone

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O t h e r a p p l i c a t i

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U H F R F I D s y s t e m O t h e r a p p l i c a t i

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U H F R F I D s y s t e m

Automatic participants tracking in Keio University Open Research Forum 2004.

UHF RFID Tag UHF RFID Antenna

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C

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5 1 1 5 2 2 5 3 5 9 5 9 2 5 9 4 5 9 6 5 9 8 6 6 2 A c c u m u l a t e d t i m e ( s e c ) N u m b e r

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p a s s i n g t h e g a t e p e r 3 s e c O p t i c a l s e n s

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Note: Not all the participants has UHF tag. Optical sensor sometimes missed counting because of overwrapping of persons and/or bags Comparison of number of passing participants Counted by using optical gate sensor and RFID reader

→Satisfactory agreement

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D e t a i l e d a n a l y s i s

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t h e r e a d i n g a c c u r a c y D e t a i l e d a n a l y s i s

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t h e r e a d i n g a c c u r a c y

Ouput level (EIRP) Test case Person 27dBm (33dBm) 23.1dBm(29.1dBm) 18dBm(24dBm) Person 1 100%(20/20) 100%(20/20) 65%(13/20) Person 2 100%(20/20) 100%(20/20) 75%(15/20) Case 1 Person 3 100%(20/20) 85%(17/20) 10%(2/20) Person 1 100%(20/20) Person 2 80%(16/20) Case 2 Person 3 85%(17/20)

100% reading accuracy for 2W transmission power

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F a c t

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s a f f e c t i n g t h e r e a d i n g a c c u r a c y F a c t

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s a f f e c t i n g t h e r e a d i n g a c c u r a c y

Transmitting power Path loss Path loss

Tag Interrogator

Minimum necessary power for Tag logic circuit Penetration loss Exposure time to the sufficient power RF wave in case of a reading of population of tags

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M u l t i p l e t a g r e a d i n g s e q u e n c e M u l t i p l e t a g r e a d i n g s e q u e n c e

Group Select Flag or state transition Interrogator Tag Query (Randomly) select slot Tag selecting particular slot broadcast with identification Collision notify (Randomly) adjust slot Broadcast with identification Singulated (State transition) Tag ID broadcast Query repeat Singulated tag dormant

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A p r e d i c t i

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6 t a g s r e a d i n g t i m e A p r e d i c t i

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6 t a g s r e a d i n g t i m e

. . 2 . 4 . 6 . 8 1 . 1 . 2 1 . 4 4 8 1 6 I n t e r r

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a t

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t

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a g l i n k s p e e d ( k b p s ) 6 t a g s r e a d i n g t i m e ( s e c )

Certain amount of continuous exposure to sufficient power of RF wave is necessary for multiple tag reading

Time to read 60 tags with 99.9% probability

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Practical power level fluctuation Practical power level fluctuation

• 70
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5000 10000 15000 Time(msec) Receive d Signal level（ dBm) Minimum power requirement One second

Path 1 Path 2

Antenna Tag

Path difference between path 1 and path generates the blind points

In practical implementation, it is not always easy to have sufficient time exposure

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F r e q u e n c y a l l

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U H F R F I D F r e q u e n c y a l l

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U H F R F I D

• Region 1 (Europe and Africa)
• RFID allocation guideline in Short Range

Device band (865-868MHz, 869.4-869.65MHz)

• ERO 70-03, ETSI technical requirements

(EN302208, EN302200)

• Region 2 (North and South America)
• ISM band allocation 902-928MHz
• FCC15.247 regulates frequency hopping

RFID system technical requirements

• Region 3 (Asia Pacific)
• No allocation
• Each administration need to establish local

radio regulations for UHF RFID

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G l

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c h a r t G l

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c h a r t

850 900 960 Korea: 908.5

• 914MHz(announced)

US:902

• 928MHz(EIRP=4W)

ETSI:865-868MHz(ERP=2W, 865.6

• 867.6MHz)

Japan: 950

• 956MHz(experimental)

Australia:915

• 928MHz(EIRP 1W)

860 870 880 890 910 920 930 940 950 An APT country:923

• 925MHz(planned)

GSM↑ GSM↓ (MHz) Aeronautical Radionavigation 1215 850 900 960 Korea: 908.5 - 914MHz(announced) US:902

• 928MHz(EIRP=4W)

ETSI:865

• 868MHz(ERP=2W, 865.6
• 867.6MHz)

Japan: 952-954MHz

• Australia:915-928MHz(EIRP 1W)

860 870 880 890 910 920 930 940 950 An APT country:923-925MHz(planned) GSM↑ GSM↓ (MHz) Aeronautical Radionavigation 1215

Internationally consistent frequency allocation is impracticable at this moment

869.4-869.65MHz(ERP=0.5W, Duty ratio 10%)

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J a p a n f r e q u e n c y a l l

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950 956 957 958

Cellular Phone RFID Candidate band Cellular phone AM Radio Relay

(MHz)

950 956 957 958

Cellular phone (IMT-2000)

(MHz)

948

Future plan Present

RFID Candidate band AM Radio Relay

Fundamental rule of frequency allocation =Newly allocated radio service (RFID) shall not cause harmful interference to the existing service.

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H a r m f u l i n t e r f e r e n c e ? H a r m f u l i n t e r f e r e n c e ? ： ： S p u r i

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s e m i s s i

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RFID Neighbor system Necessary bandwidth Frequency Power Spurious emission Signal power Leaking of RFID power may deteriorate the signal to noise ratio of the existing services.

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H a r m f u l i n t e r f e r e n c e ? H a r m f u l i n t e r f e r e n c e ? ： ： D e s e n s i t i z a t i

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D e s e n s i t i z a t i

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Neighbor system Frequency Power Signal Reception filter of neighbor system RFID emission eventually is received by the neighboring system Desired signal of the neighbor services may be suppressed due to the existence of the large RFID power the proximity. RFID

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• Licensing
• Fast track license for type certificated RFIDs
• Frequency bandwidth

952MHz～954MHz

• Maximum transmission power

4W (EIRP)

(slated to be issued early in 2005 FY) (slated to be issued early in 2005 FY)

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F u n d a m e n t a l b e n e f i t

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Present regulation

Applicant License application Administration Cellular company Application information Interference study Results Preliminary license Test License

New regulation

Applicant License application License Administration Type certificated RFID

Significant reduction of time and effort to get license

Evaluation Evaluation

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S u m m a r y S u m m a r y

• UHF band RFID features 5-10m reading
• distance. Primary target is supply chain
• management. Diverse application will be

developed once the technology is in the market.

• Reading accuracy depends on the radio

propagation environment as well as tag and reader performance.

• 952-954MHz band will be opened to RFID

system in Japan from early FY.2005.