310 likes | 401 Views
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
E N D
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