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

APRICOT 2005, Feb. 21, 2005 U H F b a n d ( 8 6 0 - 9 6 0 M H z ) R F I D U H F b a n d ( 8 6 0 - 9 6 0 M H z ) R F I D d e v e l o p m e n t i n J a p a n d e v e l o p m e n t i n J a p a n Jin Mitsugi Auto-ID Labs. Japan Keio University p . 1

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 p . 2

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. p . 3

UHF band? UHF band? TV ch.1 = 90-96MHz UHF TV TV ch.12 = 216-222MHz 470-770MHz Cellular Phone etc. Satellite Broadcasting 810-960MHz 12GHz HF VHF UHF SHF 3MHz 30MHz 300MHz 3GHz 30GHz 860-960MHz RFID 13.56MHz RFID 2.45GHz RFID Frequently referred to as UHF RFID p . 4

Typical Usages of UHF RFID Typical Usages of UHF RFID Low power type Low power type High power type High power type Interrogator Interrogator Antenna Folk Lift Top view Side view Long range, multiple tags reading Short range, individual tag reading p . 5

C l a s s o f R R F I Ds s y s t e m C l a s s o f F I D 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). p . 6

Basics of UHF passive RFID Basics of UHF passive RFID Tag Command/ Power supply Antenna Logic Antenna Response circuit Interrogator Network p . 7

Interrogator – – Tag communication Tag communication Interrogator in a nutshell in a nutshell Interrogator Tag Power supply and wake up tag Command Power supply Reply Power shall be supplied to tags by interrogator Power shall be supplied to tags by interrogator while tags reply. while tags reply. p . 8

Power level chart Power level chart 1 0 0 - 1 0 Path loss - 2 0 Power(dBW) - 3 0 - 4 0 90dB down = - 5 0 1/1000,000,000 - 6 0 - 7 0 Path loss - 8 0 - 9 0 - 1 0 0 - 1 1 0 Interrogator Interrogator Tag reply reception Output power power p . 9

F u n d a m e n t a l d i l e m m a o f p a s s i v e Ｒ Ｒ Ｆ Ｉ Ｄ F u n d a m e n t a l d i l e m m a o f p a s s i v e 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. Absorb ? Reflect? Solutions ・ Optimal design of tag impedance ・ Separate antennas for power supply and communications p . 1 0

W h a t i s t h e p u r p o s e o f U H F R F I D ? W h a t i s t h e p u r p o s e o f U H F R F I D ? Retailor Distribution Center Factory Counterfeit Theft Expiry / Overstock Accurate and real-time visibility of total supply chain by RFID p . 1 1

W h y U H F ? W h y U H F ? • Long range communications requirement Several meters reading range required p . 1 2

W h y U H F ? ( 2 ) W h y U H F ? ( 2 ) Transmitting power Wavelength ⎛ ⎞ λ ⎛ ⎞ 2 ( ) 1 G ⎜ ⎟ = ⎜ ⎟ t P G P ⎜ ⎟ π π t r r ⎝ ⎠ 2 ⎝ ⎠ 4 4 L Power reception at tag 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 p . 1 3

O t h e r a p p l i c a t i o n o f 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 o n o f U H F R F I D s y s t e m UHF RFID Antenna UHF RFID Tag Automatic participants tracking in Keio University Open Research Forum 2004. p . 1 4

C o u n t i n g a c c u r a c y c o m p a r i s o n C o u n t i n g a c c u r a c y c o m p a r i s o n Comparison of number of passing participants Counted by using optical gate sensor and RFID reader 3 0 c e s 2 5 0 3 r O p t i c a l s e n s o r e p R F I D r e a d e r e t a 2 0 g e h t g n i 1 5 s s a p n o s r 1 0 e p f o r e b 5 m u N 0 5 9 0 0 0 5 9 2 0 0 5 9 4 0 0 5 9 6 0 0 5 9 8 0 0 6 0 0 0 0 6 0 2 0 0 A c c u m u l a t e d t i m e ( s e c ) → Satisfactory agreement Note: Not all the participants has UHF tag. Optical sensor sometimes missed counting because of overwrapping of persons and/or bags p . 1 5

D e t a i l e d a n a l y s i s o n 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 o n t h e r e a d i n g a c c u r a c y Test case Person Ouput level (EIRP) 27dBm (33dBm) 23.1dBm(29.1dBm) 18dBm(24dBm) Case 1 Person 1 100%(20/20) 100%(20/20) 65%(13/20) Person 2 100%(20/20) 100%(20/20) 75%(15/20) Person 3 100%(20/20) 85%(17/20) 10%(2/20) Case 2 Person 1 100%(20/20) Person 2 80%(16/20) Person 3 85%(17/20) 100% reading accuracy for 2W transmission power p . 1 6

F a c t o r 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 o r 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 Penetration loss Transmitting power Path loss Tag Path loss Interrogator Minimum necessary power for Tag logic circuit Exposure time to the sufficient power RF wave in case of a reading of population of tags p . 1 7

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 Interrogator Tag Group Select Flag or state transition 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 tag dormant Singulated p . 1 8

A p r e d i c t i o n o f 6 0 t a g s r e a d i n g t i m e A p r e d i c t i o n o f 6 0 t a g s r e a d i n g t i m e Time to read 60 tags with 99.9% probability 1 . 4 ) c e 1 . 2 s ( e 1 . 0 m i t 0 . 8 g n i d 0 . 6 a e r 0 . 4 s g a t 0 . 2 0 6 0 . 0 4 0 8 0 1 6 0 I n t e r r o g a t o r t o T a g l i n k s p e e d ( k b p s ) Certain amount of continuous exposure to sufficient power of RF wave is necessary for multiple tag reading p . 1 9

Practical power level fluctuation Practical power level fluctuation In practical implementation, it is not always easy to have sufficient time exposure 0 dBm) -10 Receive d Signal level （ Minimum power requirement -20 One second -30 -40 -50 -60 -70 0 5000 10000 15000 Time(msec) Antenna Tag Path 1 Path difference between path 1 and path Path 2 generates the blind points p . 2 0

F r e q u e n c y a l l o c a t i o n s t a t u s f o r U H F R F I D F r e q u e n c y a l l o c a t i o n s t a t u s f o r 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 p . 2 1

G l o b a l f r e q u e n c y a l l o c a t i o n c h a r t G l o b a l f r e q u e n c y a l l o c a t i o n c h a r t -868MHz(ERP=2W, 865.6 ETSI:865 -867.6MHz) GSM ↑ GSM ↑ GSM ↓ GSM ↓ 869.4-869.65MHz(ERP=0.5W, Duty ratio 10%) ETSI:865-868MHz(ERP=2W, 865.6 -867.6MHz) US:902 US:902 -928MHz(EIRP=4W) -928MHz(EIRP=4W) Japan: 952-954MHz Japan: 950 -956MHz(experimental) - Aeronautical Aeronautical Radionavigation Radionavigation Australia:915-928MHz(EIRP 1W) Australia:915 -928MHz(EIRP 1W) Korea: 908.5 - 914MHz(announced) Korea: 908.5 -914MHz(announced) An APT country:923-925MHz(planned) An APT country:923 -925MHz(planned) 1215 1215 850 850 860 860 870 870 880 880 890 890 900 900 910 910 920 920 930 930 940 940 950 950 960 960 (MHz) (MHz) Internationally consistent frequency allocation is impracticable at this moment p . 2 2