School of HF-RFID Engineering - MyWWW ZHAWrumc/MSEwirecom/RFID_HF/MSE_HF_RFID.pdfEngineering MSE, HF-RFID, 1 HF-RFID Kontakt: ZHAW Zürcher Hochschule für angewandte Wissenschaften

School of

Engineering

MSE, HF-RFID, 1

HF-RFID

Kontakt:

ZHAW Zürcher Hochschule für angewandte Wissenschaften

Prof. Dr. M. Rupf

ZSN Zentrum für Signalverarbeitung und Nachrichtentechnik

Technikumstrasse 9, TB 425

CH-8401 Winterthur

Tel: ++41 (0)58 934 7129

Mail: [email protected]

Web: http://www.zsn.zhaw.ch

References

[1] Klaus Finkenzeller, „RFID-Handbuch“, 5. Auflage, Hanser, 2008.

[2] R. Küng, M. Rupf, „RFID-Blockkurs“, ergänzende MSE-Veranstaltung, ZHAW, 2011.

mailto:[email protected]

http://www.zsn.zhaw.ch/

School of

Engineering Inductive RFID-Reader

PA

LNA

CO

NT

RO

L U

NIT

TX DATA

RX DATA

CARRIER

ENABLE INDUCTIVE

ANTENNA L1

C1

R1

11

rCL2

1f

Reader => Tag

ASK-Modulation

serial

resonance

(current!)

from [2] MSE, HF-RFID, 2

School of

Engineering Inductive Passive Tag

Rmod (Cmod)

CLK

generator

CO

NT

RO

L U

NIT

INDUCTIVE

ANTENNA L2 C2

Cc System Clock

RX Data

Vcc

GND

C

TX Data

Reader sends unmodulated carrier

--> serves as tag supply and local oscillator

22

rCL2

1f

parallel

resonance

(voltage!)


School of

Engineering How the Tag Voltage is built V

olta

ge

at ta

g ch

ip

Frequency [MHz]

Coil only

Parallel Resonance Circuit

useful for frequencies up to 100 MHz

L2 C2

Load

13.56 MHz HF-Tag with

a coil with a few turns only

resturns

22

res

2

res 1/f~NN ~L,1/f ~L1LC)f(2πturns

LF-tag coils: 100-1000 turns => HF-tag coils: 3-10 turns (cheaper!)

Resonance peak

easily detunable

(e.g. tag near

conducting surfaces)

partly from [2] MSE, HF-RFID, 4

School of

Engineering

Available RF power (~k2) rapidly falls off with distance

even when in a range corresponding to antenna diameter

Design Rule:

Make small, antenna r2 big

2/322

RTR

2

T

2

R

xrrr

)(cosrr~k

Reading Range

rule of thumb: reading range of credit card tags ≈ diameter of reader antenna

field strength (~k)

decreases with 1/x3


-60 dB / decade

School of

Engineering

Inlays receive power by magnetic

coupling with the antenna and will

receive maximum power when in

their best orientation. Source: TI

Best Orientation

Source: TI Source: TI

MSE, HF-RFID, 6

School of

Engineering Reader => Tag: ASK-Modulation

ASK modulation depth 10-100%


School of

Engineering Tag => Reader: Load Modulation

t

e.g. data 0 (Manchester coded)

Tb e.g. fsubcarrier = fc / 32

Source [1]

Tb carrier fc (not shown) t

e.g. data 0

Rx-signal = AM with carrier!

y(t)

y(t)

e.g. Rb = 1/Tb = fc / 512

FET-switch

closed

envelope

uplink

partly from [1] MSE, HF-RFID, 8

School of

Engineering

Tag-response in baseband

Tag-response subcarrier-modulated

fsub -fsub

Tag-response @ reader

f

Tag => Reader: Load Modulation MSE, HF-RFID, 9

t Tb

f t Tb

Tb t

envelope

fc+fsub

f fc-fsub fc

0

0

School of

Engineering Tag => Reader: Load Modulation

f

IY(f)I

fc+fsubcarrier fc-fsubcarrier fc

huge dynamic range

(e.g. 80 dB)

filtering

sideband

(with info)

f fc + 423.75 kHz fc

13.56 MHz

antenna BP-characteristic

(Q = fc / B3dB < 20

rec. for ISO 15693)

fc - 423.75 kHz

- 3 dB

Q too large

Spectrum of the Rx-signal

IY(f)I

Q-factor of inductive reader- and tag-antenna

compromise between long range (high voltage peak) and

good carrier-subcarrier separation (facilitates demodulation)

MSE, HF-RFID, 10

School of

Engineering HF-Band-Regulations World-Wide

Frequency bands in use:

Most important band today is UHF

Source: ERC/REC 70-03 Annex 9

• Only 1 single channel

• Tight transmit spectral mask

• Far field limit at 10 m

13.553 - 13.567 MHz

42 dBuA/m at 10 m


School of

Engineering Some LF- and HF-RFID-Standards

Goal

readers and tags from different suppliers are interoperable

typically Tx-procedure is standardized, but not the Rx => contention!

LF

ISO/IEC 11784/5 and extension 14223 identification of animals

HF

ISO/IEC 14443 Identification Cards – Proximity Cards (2001)

range up to 10 cm, data rate 106 kb/s, more details later

ISO/IEC 15693 Identification Cards – Vicinity Cards (2001)

range up to 1 m, data rates up to 26 kb/s

also ISO/IEC 18000-3 mode 1

ISO/IEC 18000-3 mode 3 (item management standard)

HF-version of EPC UHF Gen2, high data and tag reading rates

more details later

MSE, HF-RFID, 12

School of

Engineering Near Field Communication (NFC) MSE, HF-RFID, 13

NFC-device

e.g. with OS

ISO-15693 ISO-14443 A/B

VCD mode

reader/writer

26 kbps

PCD mode

reader/writer

106 kbps

VICC PICC PCD NFC-device

NFC-mode

peer-to-peer

106 / 212 / 424 kbps

(> 424 kbps in R&D)

13.56 MHz

inductive

(few cm)

passive communication mode active comm. mode

PICC mode

card-emulation

≥ 106 kbps

NFC-Interface and Protocol Standards

NFCIP-2 (ECMA-352 / ISO-21481)

NFCIP-1 (ECMA-340 / ISO-18092)

NFC-Controller mit NFCIP-2

RF-detection, set-up-time < 0.1s

memory card memory card

processor card

School of

Engineering HF-RFID-Standard ISO-15693

Norm for contactless chip-cards

basis for many other smart-label-products

13.56 MHz, range < 1 m (vicinity coupling)

Standard from 2001 with 3 parts

ISO 15693-1:2000: Physical Characteristics CHF 50.-

http://www.iso.org/iso/iso_catalogue/catalogue_ics/catalogue_detail_ics.htm?csnumber=30995

ISO 15693-2:2006: Air Interface and Initialization CHF 80.-

http://www.iso.org/iso/catalogue_detail.htm?csnumber=39695

ISO 15693-3:2009: Anticollision and transmission protocol CHF 142.-

http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=43467

Terms and definitions

VCD: vicinity coupling device („reader“)

VICC: vicinity card („tag“)

MSE, HF-RFID, 14

http://www.iso.org/iso/iso_catalogue/catalogue_ics/catalogue_detail_ics.htm?csnumber=30995



http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=43467

School of

Engineering VCD-to-VICC Communication

ASK-Modulation

„The VICC shall decode both. The VCD determines which index is used.“

Source: ISO-15693-standard


ASK-modulation with 10% and 100% modulation depth

MSE, HF-RFID, 15

School of

Engineering VCD-to-VICC Communication

Pulse Position Modulation

1 out of 256 data coding (long distance mode)

1 out of 4 data coding (fast mode)

75.52 μs

0 1 2 3

26.48 kb/s

1.65 kb/s

SOF

(start of

frame)

EOF

(end of

frame)


MSE, HF-RFID, 16

School of

Engineering VICC-to-VCD Communication

Operating field

A VICC shall operate … between Hmin (150 mA/m) and Hmax (5 A/m rms).

Load modulation

inductive coupling

Data rates and subcarrier

one subcarrier: fs1 = fc/32 (423.75 kHz)

two subcarrier: fs1 = fc/32 (423.75 kHz) and fs2 = fc/28 (484.28 kHz)

(FSK)


MSE, HF-RFID, 17

School of

Engineering VICC-to-VCD Communication

Bit-coding when using one subcarrier (high bit rate)

Logic 1 (Manchester coding)

Bit-coding when using two subcarrier (high bit rate)

Logic 0 (Manchester coding)



SOF

(start of

frame)

EOF

(end of

frame)

SOF

(start of

frame)

EOF

(end of

frame)

MSE, HF-RFID, 18

School of

Engineering Anticollision and Transmission Protocol

VICCs are uniquely identified by a 64 bit unique identifier (UID)

Application family identifier (AFI)

used to extract only the VICCs meeting the required application

criteria (e.g. transport etc.), AFI-support by the VICCs is optional

VICC memory organization

=> can be locked (permanently) or not locked



MSE, HF-RFID, 19

Please note that Tags just support 32 bit memory blocks today. Therefore, some Tags have a memory with

2048 x 32 bit blocks. But then, a special flag must be used which is not supported by all Reader (versions).

School of


Overall protocol description

VCD talks first

General request format

General response format

time

VCD VICC

Request

Response



MSE, HF-RFID, 20

School of


Inventory request inventory


MSE, HF-RFID, 21

School of


Inventory request

VICC responds if …

success idle

Slot-number = 4 LSBs of the UID

if the mask is empty

EOF/SOF

see ISO 15693-3:1999, chapter 8.3

UID


MSE, HF-RFID, 22

School of

Engineering

Assume there are 4 Tags in the Reader field with UIDs 81 (hex: 51)

85 (hex: 55)

165 (hex: A5)

170 (hex: AA)

ISO-15693 Anticollision: Example MSE, HF-RFID, 23

-

C

C - - - - - - - 81 170 - - - - - -

5

85 165 - - - - - - - - - - - - - -

School of

Engineering Command Codes (Requests)

exits when power off, reset to ready, …

VICC

locks permanently the requested block

enters the selected state

exits the quiet state

(over) writes the application family ID

locks the AFI permanently

(over) writes data storage format identifier

sends system information


MSE, HF-RFID, 24

School of

Engineering Read Single Block

VCD VICC

time

typ. 32 bits

unadressed

Fastest access to moving tags (e.g. on conveyor belt / production line)

● Tag "identification" with (32 bit) memory-block and not with the UID

● no anticollision procedure, at most 1 Tag in the (small) Reader field

● Minimum exposure time in the Reader field ≈ 8 ms

(cf. Exercise 1, problem 8) => up to 125 moving Tags per s readable


MSE, HF-RFID, 25

Documents

School of HF-RFID Engineering - MyWWW ZHAWrumc/MSEwirecom/RFID_HF/MSE_HF_RFID.pdfEngineering MSE, HF-RFID, 1 HF-RFID Kontakt: ZHAW Zürcher Hochschule für angewandte Wissenschaften