[go: up one dir, main page]
More Web Proxy on the site http://driver.im/

WO2010007540A1 - Protocole de transmission rfid et procédé de fonctionnement d’un transpondeur - Google Patents

Protocole de transmission rfid et procédé de fonctionnement d’un transpondeur Download PDF

Info

Publication number
WO2010007540A1
WO2010007540A1 PCT/IB2009/051980 IB2009051980W WO2010007540A1 WO 2010007540 A1 WO2010007540 A1 WO 2010007540A1 IB 2009051980 W IB2009051980 W IB 2009051980W WO 2010007540 A1 WO2010007540 A1 WO 2010007540A1
Authority
WO
WIPO (PCT)
Prior art keywords
transponder
transmission
period
response signal
reader
Prior art date
Application number
PCT/IB2009/051980
Other languages
English (en)
Inventor
William Hendrik Hofmeyr
Hendrik Lodewyk Van Eeden
Original Assignee
Ipico South Africa (Pty) Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ipico South Africa (Pty) Limited filed Critical Ipico South Africa (Pty) Limited
Publication of WO2010007540A1 publication Critical patent/WO2010007540A1/fr

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
    • G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
    • G06K19/0723—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/0008—General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer

Definitions

  • This invention relates to wireless radio frequency identification (RFID) systems and more particularly to a transponder forming part of such a system and a communications protocol for use with such as system.
  • RFID radio frequency identification
  • the invention also relates to a method of operating a transponder of an RFID system.
  • RFID systems are known in which a plurality of RFID transponders are activated by a power-up or interrogation signal from an RFID reader.
  • the transponders then transmit respective response signals, usually comprising identification data, to a receiver, which typically forms part of an RFID reader or interrogator.
  • the transmissions of the transponders are organised in time, so that there exists a real probability that one transponder transmits its response signal at a time when no other transponder is transmitting, thereby enabling the interrogator to receive the response signal successfully.
  • Another object of the protocols is to ensure that the transmissions of all the transponders in a transponder population to be read, are received successfully within a reasonable (as short as possible) time.
  • the transponders initiate the anti- collision protocol by automatically transmitting a respective response signal, when the transponder is exposed to an energizing beam generated by the reader.
  • These protocols are known as "Transponder Talks First” (TTF) protocols.
  • TTF identification systems are known in which the RFID reader transmits a mute signal, to mute a transponder after having read or identified the transponder. The purpose is to reduce the population of transponders still to be read and thereby accelerating the identification process. TTF identification systems are also known in which, when one transponder has started to transmit its response signal, the RFID reader transmits a signal to mute all other transponders. The purpose in this case is to prevent the other transponders from interfering with the currently transmitting transponder and in so doing, accelerate the identification process.
  • TTF protocols A special case of TTF protocols is also known in which the reader does not send any commands to the transponders - these protocols may be referred to as "Transponder Talks Only" protocols, see for example USA 6, 154, 136.
  • TTO transponders normally do not require any form of signal detector, since no signal or command is being sent by the reader, to control the anti-collision process.
  • the main advantage of TTO protocols is that the lack of reader modulation results in less interference and the ability to deploy multiple TTO readers in close proximity and in the same frequency band.
  • TTO protocols are perhaps slower than TTF or "Reader Talks First" (RTF) protocols, because there is no signalling from the reader to the transponders that can control or accelerate the anti-collision process.
  • RTF Reader Talks First
  • a transponder for use in a population of transponders in a radio frequency identification system, the transponder comprising a detector sensitive to a transmission by another source of transmission; and a controller responsive to the detector for delaying transmission by the transponder of a response signal, until after the transmission by the other source.
  • the other source may be another transponder in the population of transponders.
  • the transponder is preferably configured automatically to transmit a response signal after having been exposed to an energizing field and does not require interrogation by the reader, before transmitting the response signal.
  • the transponder may be suitable for use with a
  • TTF Transponder Talks First
  • TTO Transponder Talks Only
  • the transponder may be configured to schedule transmissions of the response signal at pseudo-random inter-transmission intervals, the response signal comprising a data packet having a packet period and comprising a plurality of bits, each having a bit period.
  • the detector may be configured to be sensitive to the transmission by the other source during a first period before, preferably immediately before, each of the scheduled transmissions, and the controller may be responsive, in the event of a transmission by the other source, to delay the scheduled transmission by a second time period.
  • the detector may be an amplitude modulation detector configured to detect transmissions comprising a modulating signal having a bit rate of about 256kbits/s or 128kbits/s.
  • the first time period may be equal to the bit period or a plurality of bit periods (for example two or three), alternatively in the order of the packet period.
  • the second time period may be equal to the bit period or a plurality of bit periods (for example two or three), alternatively in the order of the packet period.
  • the transponder may be a dual frequency channel transponder utilizing a first frequency channel to receive the energizing signal and a second frequency channel to transmit the response signal and the detector may be sensitive to signals in the second channel.
  • the first and second frequencies may be different.
  • the invention also extends to a protocol for a radio frequency identification system comprising a reader and a plurality of transponders constituting a transponder population to be read by the reader, wherein there is no modulation by the reader of a reader signal, the transponders being configured to re-transmit a response signal at pseudo random inter-transmission intervals, at least some of the transponders being sensitive to transmissions by another source, and to delay a scheduled transmission of the response signal, until after the transmission by the other source.
  • the other source may be another transponder in the population, but may also be another source in the system or an external source.
  • radio frequency identification system comprising a transponder as herein defined and/or described.
  • the invention also includes within its scope a method of operating a transponder of a radio frequency identification system comprising a reader and a plurality of transponders constituting a transponder population, the method comprising the steps of causing the transponder: while being exposed to an energizing field, automatically to re-transmit a response signal at pseudo random inter- transmission intervals; during a first time period before a scheduled transmission of the response signal, to sense whether another source is transmitting; and if a transmission by another source is detected during the first time period, to delay the scheduled transmission by a second time period.
  • figure 1 is a basic block diagram of a radio frequency identification system and comprising a plurality of transponders
  • figure 2 is a basic block diagram of the transponder according to the invention
  • figure 3 is a flow diagram of a method according to the invention of operating a transponder
  • figure 4 is a first time diagram illustrating operation of the transponder and the system
  • figure 5 is a second time diagram illustrating operation of the transponder and the system
  • figure 6 is a basic block diagram of another embodiment of the transponder according to the invention.
  • a wireless radio frequency identification (RFID) system is generally designated by the reference numeral 10 in figure 1 .
  • the system 10 comprises a reader 1 2 and a population of transponders 1 4.1 to 1 4.n.
  • the reader generates an energizing signal 1 6, which is broadcast, to be received by the transponders of the population to be read.
  • the transponders are passive transponders, the transponders derive energy from the signal 1 6 and store the derived energy in respective local charge storage devices (not shown) to power local circuits of the transponder.
  • this invention is not limited to passive transponders, but may be used with active and semi-active or battery assisted transponders as well.
  • the transponders 14.1 to 14.n are "Transponder Talks Only” (TTO) transponders and are configured automatically to respond by repeatedly retransmitting a response signal comprising a data packet, preferably comprising respective identification data (ID) associated with the transponder.
  • TTO Transponder Talks Only
  • Each transponder comprises means
  • a chip 20 of a passive UHF RFID transponder 14.1 to 14.n comprises a rectifier capable of rectifying incident RF energy in the UHF band followed by a regulator for supplying a known and steady supply voltage to the rest of the circuit, an oscillator for generating a 512 kHz clock to the logic, a Power-on-Reset to the logic, and a logic block 22 implementing a protocol engine comprising various digital circuits, state machines and a memory arrangement 24, e.g. EEPROM.
  • the UHF RFID transponder When exposed to the energizing field 16, the UHF RFID transponder transmits (backscatters) by means of modulator 25 a response signal comprising a unique factory programmed ID code stored in the memory 24 at pseudo-random intervals.
  • the ID code comprises 64 bits of information preceded by an 1 1 -bit preamble, for a total packet of 75 bits.
  • the data is transmitted at a rate of approximately 256 kbits/s.
  • the interval between response signal transmissions varies pseudo randomly in a range between 0 and
  • the chip 20 also comprises an AM detector 26 capable of detecting transmissions by another source, including similar transponders 14.1 to 14.n in the same reader beam 1 6, i.e. data transmissions at approximately 256 kbit/s.
  • the detector is also capable of detecting noise sources in the same band that could potentially interfere with the reception by the reader of the response signals comprising the ID packets. Such noise sources could in practice be relatively wide band, implying that the detector 26 must be capable of detecting wide band interference, e.g. 10 kHz to 900 kHz.
  • the detector should at least be sufficiently sensitive to detect backscatter modulation by neighboring transponders, typically at less than 0 dBm to 80 dBm.
  • transponder 14.1 is, by virtue of the detector 26, sensitive to ongoing transmissions by any of the other transponders 14.2 to 14.n in the population that may be exposed to the energizing beam, or to noise that could cause interference.
  • the scheduled response signal is delayed by a second time T2 as shown at 34, so as to avoid a possible collision between the scheduled response signal and the ongoing transmission or noise.
  • This process can be repeated, i.e. the scheduled response signal can be delayed by additional T2 periods, until no transmission or noise is detected in a period T1 immediately preceding the scheduled transmission.
  • transponder 14.1 during first period T1 before a scheduled ID packet transmission 40 by transponder 14.1 (indicated at TR14. V), there is an on-going transmission of an ID packet 42 by transponder 14.2.
  • a local controller of transponder 14.1 causes the scheduled transmission 40 to be delayed by a second time period 12, which is of the order of one or two or three bit periods, i.e. between 3.9//S and 1 1 .7 ⁇ s.
  • the delayed and actual transmission of transponder 14.1 is shown at 44, and it is clear that interference by and/or on transmission 42 is avoided.
  • transponder 14.1 remains so sensitive to on-going transmissions, until immediately before the actual transmission 44.
  • T2 is of the order of a complete packet length, i.e. about 300// s. It will be appreciated that T1 may then in effect also be at least as long as T2.
  • a passive dual frequency RFID transponder 50 comprises first and second coil antennas.
  • the first coil 52 is resonant at a low frequency (LF), typically 125 kHz - 135 kHz.
  • the second coil 54 is resonant at a high frequency (HF), typically 6.8 MHz or 1 3.56 MHz.
  • LF low frequency
  • HF high frequency
  • the RFID reader 12 (shown in figure 1 ) transmits an energizing beam 16 at the low frequency. This signal is picked up by the LF coil and rectified by rectifier 53 to provide power to the chip 56.
  • the chip 56 comprises a regulator for supplying a known and steady supply voltage to the rest of the circuit, an oscillator for generating a 256 kHz clock to the logic, a Power-on- Reset to the logic, and a logic block implementing a protocol engine comprising various digital circuits, state machines and memory 58, e.g. EEPROM.
  • the dual frequency RFID transponder 50 transmits a response signal comprising a unique factory programmed ID code stored in the memory 58 at pseudorandom intervals to the RFID reader 10. This is done by pulsing the HF coil 54 so that it rings at its resonant frequency.
  • the ID code comprises 64 bits of information preceded by an 1 1 - bit preamble, for a total of 75 bits. The data is transmitted at a rate of approximately
  • the interval between response signal transmissions varies pseudo randomly between 0 and 130 ms.
  • a dual frequency transponder of the kind described hereinbefore transmits a response signal to the reader
  • the HF coils of similar transponders in the transponder population ring in sympathy, and so pick up the transmitted pulses.
  • An AM detector 60 connected to the HF coil is capable of detecting transmissions of other similar transponders in the same reader beam, i.e. data transmissions at approximately 128 kbit/s.
  • the detector is also capable of detecting noise sources in the same band that could potentially interfere with the response signals comprising the ID packets. Such noise sources could in practice be quite wide band, implying that the detector must be capable of detecting wide band interference, e.g. 10 kHz to 450 kHz.
  • the transponder 50 by virtue of detector 60 is sensitive to ongoing transmissions from other similar transponders that are also exposed to the reader energizing beam, or to noise that could cause interference.
  • T1 and T2 is of the order of one or two bit periods, i.e. between 7.8 ⁇ s and 15.6//S.
  • T1 and T2 are of the order of a complete packet length, i.e. about 586 ⁇ s.
  • T1 may also be of the order of one or two bit periods, i.e. between 7.8 ⁇ s and 15.6//S, while T2 is of the order of a complete packet length, i.e. about 586 ⁇ s.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Artificial Intelligence (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

L'invention porte sur un transpondeur (20) pour un système d'identification radiofréquence (10) qui comprend un détecteur (26) sensible à une transmission par une autre source. Un contrôleur (22) du transpondeur est sensible au détecteur pour retarder un signal de réponse par le transpondeur, jusqu'à après la transmission par l'autre source.
PCT/IB2009/051980 2008-07-17 2009-05-13 Protocole de transmission rfid et procédé de fonctionnement d’un transpondeur WO2010007540A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ZA2008/06225 2008-07-17
ZA200806225 2008-07-17

Publications (1)

Publication Number Publication Date
WO2010007540A1 true WO2010007540A1 (fr) 2010-01-21

Family

ID=40873530

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2009/051980 WO2010007540A1 (fr) 2008-07-17 2009-05-13 Protocole de transmission rfid et procédé de fonctionnement d’un transpondeur

Country Status (1)

Country Link
WO (1) WO2010007540A1 (fr)

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5680459A (en) * 1994-04-29 1997-10-21 Kasten Chase Applied Research Limited Passive transponder
US6154136A (en) * 1998-02-26 2000-11-28 Van Eeden; Hendrik Lodewyk Free running RF identification system with increasing average inter transmission intervals
US6535109B1 (en) * 1998-12-01 2003-03-18 Texas Instruments Sensors And Controls, Inc. System and method for communicating with multiple transponders
US20030094491A1 (en) * 2001-11-20 2003-05-22 Futoshi Nakabe Contactless IC card, responding method, and program therefor
US20030116626A1 (en) * 2001-12-20 2003-06-26 Matsushita Electric Industrial Co., Ltd. IC card reader/writer, identification method and program
EP1422652A2 (fr) * 2002-11-20 2004-05-26 Siemens Aktiengesellschaft Procédé pour la transmission sans collision d'informations entre un appareil de lecture/écriture et un support d'information mobile, appareil de lecture/écriture, support d'information mobile et système d'identification
US20040185806A1 (en) * 2001-05-03 2004-09-23 Hendrik Van Zyl Smit Communication between a transponder and an interrogator
US20060031546A1 (en) * 2002-09-11 2006-02-09 Koninklijke Philips Electronics, N.V. Method of reading a plurality of non-contact data carriers, including an anti-collision scheme
US7187692B1 (en) * 1999-11-04 2007-03-06 Matsushita Electric Industrial Co., Ltd. Information communication system, noncontact IC card, and IC chip

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5680459A (en) * 1994-04-29 1997-10-21 Kasten Chase Applied Research Limited Passive transponder
US6154136A (en) * 1998-02-26 2000-11-28 Van Eeden; Hendrik Lodewyk Free running RF identification system with increasing average inter transmission intervals
US6535109B1 (en) * 1998-12-01 2003-03-18 Texas Instruments Sensors And Controls, Inc. System and method for communicating with multiple transponders
US7187692B1 (en) * 1999-11-04 2007-03-06 Matsushita Electric Industrial Co., Ltd. Information communication system, noncontact IC card, and IC chip
US20040185806A1 (en) * 2001-05-03 2004-09-23 Hendrik Van Zyl Smit Communication between a transponder and an interrogator
US20030094491A1 (en) * 2001-11-20 2003-05-22 Futoshi Nakabe Contactless IC card, responding method, and program therefor
US20030116626A1 (en) * 2001-12-20 2003-06-26 Matsushita Electric Industrial Co., Ltd. IC card reader/writer, identification method and program
US20060031546A1 (en) * 2002-09-11 2006-02-09 Koninklijke Philips Electronics, N.V. Method of reading a plurality of non-contact data carriers, including an anti-collision scheme
EP1422652A2 (fr) * 2002-11-20 2004-05-26 Siemens Aktiengesellschaft Procédé pour la transmission sans collision d'informations entre un appareil de lecture/écriture et un support d'information mobile, appareil de lecture/écriture, support d'information mobile et système d'identification

Similar Documents

Publication Publication Date Title
US6952157B1 (en) System and method for concurrently addressing multiple radio frequency identification tags from a single reader
US10474851B2 (en) Systems and methods for collision avoidance in a multiple RFID interrogator environment
EP1017005B1 (fr) Système et méthode pour communiquer avec plusieurs transpondeurs
EP0898815B1 (fr) Dispositif de communication a transpondeur
US6456191B1 (en) Tag system with anti-collision features
EP1977375B1 (fr) Procédé de prévention de collisions entre des lecteurs rfid dans un système rfid
US9661401B2 (en) Locating a backscatter-based transponder
US20100156610A1 (en) Rfid repeater for range extension in modulated backscatter systems
US20040066281A1 (en) System and method to identify multiple RFID tags
US20070046459A1 (en) Methods and apparatus for asset tracking
US20020024421A1 (en) Apparatus and method for preventing data collision in a radio frequency identification tag system
US20120126952A1 (en) Communication Method in RFID or Remote Sensor Systems
US20070075838A1 (en) Method and apparatus for avoiding radio frequency identification (RFID) tag response collisions
JP2010504679A (ja) Ｒｆｉｄタグ
EP2987113B1 (fr) Définition de zone de lecture d'identification radiofréquence
US6150934A (en) Electronic communication system between a base station and transponders
US20080224873A1 (en) Apparatus and method for detecting wake-up burst of active rfid tag
WO2001033725A1 (fr) Systeme de communication d'information, carte a circuit imprime sans contact et puce associee
EP3899795A1 (fr) Étiquette et système rfid multiprotcole
WO2010007540A1 (fr) Protocole de transmission rfid et procédé de fonctionnement d’un transpondeur
EP2509027B1 (fr) Procédé de gestion de collision dans un système d'identification
US20050231326A1 (en) Maintenance of an anticollision channel in an electronic identification system
US20140036902A1 (en) Method, Apparatus, and Logic for Wireless Data Transmission
US20110148599A1 (en) Rfid reader, rfid tag, and method of recognizing plurality of rfid tags
JPH08167090A (ja) 移動体識別方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 09786394

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 09786394

Country of ref document: EP

Kind code of ref document: A1