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Explore the operational techniques of RFID technology, its applications in toll collection, asset tracking, and more, modulation techniques, RFID standards, and the future of RFID technology.
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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
Reader and Tags (Label) • Reader and Tag (Label)
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 known as a transponder (TRANSmitter + resPONDER). • For the purposes of this overview, an RFID device that actively transmits to a reader is termed an “active” tag; an RFID device that only reflects or backscatters transmission from a reader is termed “passive.”
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 system used in Japan. • The other is the EPC coding system used in US, Euro 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 manufacturer number; • an object class and a serial number which define product type and product number
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
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 standards 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
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, Identification 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