RFID Review

科法所 李啟民R94a41002

Dec. 27, 2005

Outline

Introduction Operation Techniques Conclusions References

Introduction RFID technology has been commercially available for

over two decades, tracing its roots back to military

Identification Friend or Foe (IFF) systems of the 1940s.

Introduction-Applications

Electronic Toll Collection (ETC ) Railway car identification and tracking Asset identification and tracking Item management for retail, health care, and

logistics applications Access Control Animal identification Security

Basic Operations

Reader and Tags (Label)

Reader and Tag (Label)

Backscatter Transmission

Backscatter Transmission

Transponder/ Tag An RFID device that did not actively transmit to a reader

was known as a tag. An RFID device that actively transmitted to a reader was k

nown as a transponder (TRANSmitter + resPONDER). For the purposes of this overview, an RFID device that acti

vely transmits to a reader is termed an “active” tag; an RFID device that only reflects or backscatters transmission from a reader is termed “passive.”

Tag

Antenna

Each RFID system includes at least one antenna to transmit and receive the RF signals.

In some systems, a single antenna transmits and receives the signals; in other systems, one antenna transmits and one antenna receives the signals.

The quantity and type of antennas used depend on the application.

RF Transceiver The RF transceiver is the source of the RF energy

used to activate and power the passive RFID tags. The RF transceiver may be enclosed in the same

cabinet as the reader or it may be a separate piece of equipment.

When provided as a separate piece of equipment, the transceiver is commonly referred to as an RF module.

The transceiver filters and amplifies the backscatter signal from a passive RFID tag.

RFID Electronic coding system

Two coding systems in current RFID system One is the Ubiquitous ID （ UID ） coding syste

m used in Japan. The other is the EPC coding system used in US, E

uro and China.

EPC Structure EPC Structure (Electronic Product Code)

EPC Structure a header, defining the variety of EPC among a number of

possible structures; a domain manager number which is effectively a manufa

cturer number; an object class and a serial number which define product

type and product number

EPC Class

RFID v.s. Bar Code

Modulation Techniques RFID systems usually employ modulation techniques

and coding schemes that are simple to produce. For example, in ISO 18000 Type C

Double Side Band-Amplitude Shift Keying (DSB-ASK), Single Side Band-ASK (SSB-ASK) Phase Reversal-ASK (PR-ASK). FHSS and DSSS

Frequency Hopping SS

Direct Sequence SS

In DSSS, the rate of the spreading code signal is called the chip rate. The ratio of chip rate and data rate is the processing gain of spreading factor.

CDMA Concept

Receiver of a DSSS signal

FHSS/ DSSS In frequency hopping, the carrier frequency of the

modulated information signal is not constant but changes periodically.

The set of available frequencies the carrier can attain is called the hop-set.

FH system uses only a small part of the bandwidth when it transmits while a DS system occupies the whole frequency band.

FHSS/ DSSS

Time /Frequency Occupancy of FH and DS signals

RFID Standards The International Standards Organization (ISO) has three s

tandards for RFID: ISO 14443 (for contactless systems), ISO 15693 (for vicinity systems, such as ID badges), and ISO 18000 (to specify the air interface for a variety of

RFID applications). A not-for-profit organization, EPCglobal, has developed a

widely accepted standard for product identification.

Spectrum In Us, FCC uses 902 - 928 MHz spectrum In Euro, ETSI adopts 866 - 868 MHz In Japan, 950 - 956 MHz and 2.45 GHz 、 13.56 MHz are

available In China, spectrum 900 MHz

Operating Frequency of RFID

Conclusions

RFID is a convenient and low cost technique that can applied to many short range wireless applications 。

Standardization is still an important issue to realize.

Privacy concerns

References EPC Tag Data Standards Version 1.1 Rev.1.24, Standard Specification

01 April 2004 13.56 MHz ISM Band Class 1Radio Frequency Technical report, Ident

ification Tag Interface Specification: Candidate Recommendation, Version 1.0.0

A COMPARISON OF HF AND UHF RFID TECHNOLOGIES By Philips Semiconductors.

Landt, J. “The history of RFID”, Potentials, IEEE Volume 24,  Issue 4,  Oct.-Nov. 2005 Page(s):8 – 11, Digital Object Identifier 10.1109/MP.2005.1549751

RFID: a technical overview and its application to the enterpriseWeinstein, R.; IT Professional, Volume 7,  Issue 3,  May-June 2005 Page(s):27 - 33 , Digital Object Identifier 10.1109/MITP.2005.69