RFID Review R 94 a 41002 Dec 27

RFID Review 科法所 李啟民 R 94 a 41002 Dec. 27, 2005

Outline n n Introduction Operation Techniques Conclusions References

Introduction n RFID technology has been commercially available for over two decades, tracing its roots back to military Identification Friend or Foe (IFF) systems of the 1940 s.

Introduction-Applications n n n n 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) n Reader and Tag (Label)

Backscatter Transmission

Backscatter Transmission

Transponder/ Tag n n n 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 + res. PONDER). 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. ”

Tag

Antenna n n n 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 n n 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 n n n 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 n EPC Structure (Electronic Product Code)

EPC Structure n n n 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

EPC Class

RFID v. s. Bar Code

Modulation Techniques n n n 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 n 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 n Receiver of a DSSS signal

FHSS/ DSSS n n n 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 n Time /Frequency Occupancy of FH and DS signals

RFID Standards n n n 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 n n 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 n n n 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 n n n EPC Tag Data Standards Version 1. 1 Rev. 1. 24, Standard Specification 01 April 2004 13. 56 MHz ISM Band Class 1 Radio 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 enterprise Weinstein, R. ; IT Professional, Volume 7, Issue 3, May-June 2005 Page(s): 27 - 33 , Digital Object Identifier 10. 1109/MITP. 2005. 69