CN1201540A - Enhanced detection of multiple data transmissions - Google Patents
Enhanced detection of multiple data transmissions Download PDFInfo
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- CN1201540A CN1201540A CN96198155A CN96198155A CN1201540A CN 1201540 A CN1201540 A CN 1201540A CN 96198155 A CN96198155 A CN 96198155A CN 96198155 A CN96198155 A CN 96198155A CN 1201540 A CN1201540 A CN 1201540A
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- protection
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- local timing
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- 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
- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
- G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
- G06K7/10019—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers.
- G06K7/10029—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers. the collision being resolved in the time domain, e.g. using binary tree search or RFID responses allocated to a random time slot
- G06K7/10059—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers. the collision being resolved in the time domain, e.g. using binary tree search or RFID responses allocated to a random time slot transponder driven
-
- 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
- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
-
- 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
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- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
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- Health & Medical Sciences (AREA)
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- Computer Vision & Pattern Recognition (AREA)
- Electromagnetism (AREA)
- General Health & Medical Sciences (AREA)
- Computer Networks & Wireless Communication (AREA)
- Radar Systems Or Details Thereof (AREA)
- Mobile Radio Communication Systems (AREA)
- Computer And Data Communications (AREA)
- Small-Scale Networks (AREA)
- Near-Field Transmission Systems (AREA)
- Synchronisation In Digital Transmission Systems (AREA)
Abstract
The present invention provides method and apparatus which enhance the probability of identification of a number of transmitters (typically transponders) which are all transmitting data to a receiver. The invention is applicable to a number of systems including passive radio-frequency transponders systems, systems in which a number of self-powered transmitters must be identified by a receiver, or systems in which a number of transmitters broadcast using a randomly delayed 'back-end and retry' algorithm. Each transmitter is adapted to transmit at intervals and comprises means for generating transmissions, means for calculating the duration of the intervals between successive transmissions and means for enabling the transmitter at random or pseudo-random intervals related to an operating frequency of local timing means. In passive RFID systems, the frequency of the local timing means is indeterminate, being unspecified until the transmitter is in operation.
Description
Background of invention
The present invention relates to discern the method for a plurality of transmitters, each transmitter sends data to receiver in each time interval.The present invention also relates to comprise the recognition system of a plurality of transmitters and a receiver and relate to transmitter itself.The invention still further relates to and be used for improving at EP494, among the 114A particularly at EP585, the method and apparatus of disclosed recognition system among the 132A.
Known recognition system, wherein a plurality of transmitters, transponder is started by interrogating signal typically, and then, the answer signal that transmission generally includes recognition data is to receiver, and it typically constitutes the part of interrogator.These signals can be transmitted in many ways, comprise electromagnetic energy, radio frequency (RF) for example, and infrared ray (IR), and coherent ray, and acoustic energy, for example ultrasonic.For example, transmission can be by by transmitter actual transmission RF energy, or the reflectivity of modulation transmitter antenna, with cause from the transmitter antenna reflection or backward scattered interrogating signal the variable quantity of RF energy, and be done.
Usually, if the sending overlap of two transmitters or conflict, then transmission can be lost, because receiver can not be distinguished each independent transmission.Like this, system must make each transmitter repeatedly launch, and occurs in " quietness " time up to its emission, and till successfully being received by interrogator.GB2,116,808A discloses a kind of recognition system, and wherein each transponder is programmed to send data again with pseudo-random fashion.The timing signal of transponder draws from crystal oscillator in this recognition system, therefore, makes the making of transponder more expensive.
EP467,036A have described another kind of recognition system, and it has used the pseudorandom time-delay between the transponder data send.In this embodiment, the linear regression sequencer comes seeding by the transponder identification address, makes the pseudorandom time-delay as far as possible at random.
An object of the present invention is to provide the replacement system that is used to strengthen the detection that the multipath transmission of this type systematic is carried out.
EP494,114A and EP585,132A discloses recognition system, and wherein transponder can be programmed with identical data.A purpose of this invention provides improved recognition system, is used to be created in the pseudorandom time-delay between the transponder transmission.
Brief summary of the invention
According to a first aspect of the present invention, the method of discerning a plurality of transmitters is provided, each transmitter sends data to a receiver in some time intervals, this method comprises by each emission function work was changed by the interval duration between the sending in succession of each transmitter, these time intervals by randomly or pseudorandom ground calculate, and relevant with the frequency of operation of the local timing device of being correlated with of this transmitter.
The time interval preferably changes between maximum duration relevant with the predetermined period number of local timing device and minimum interval.
In above method, the interval duration between sending, can be by generating pseudo random number periodically, and pseudo random number and output by the counter device of local timing device clock synchronization (clocked) compared, and when pseudo random number is consistent with the output of counter device, make the work of emission function, and calculated.
According to a second aspect of the present invention, recognition system is provided, comprise a plurality of transmitters that each transmitter wherein is suitable for sending in the time interval, be used to receive receiver with at least one from the transmission of transmitter, each transmitter comprises the device that is used to produce transmission, be used to calculate the device of the interval duration between the transmission in succession, and be used to make the emission function relevant with the frequency of operation of local timing device at random or the pseudorandom time interval in the device of working.
According to a third aspect of the present invention, the transmitter that is suitable for sending in the time interval is provided, comprise the device that is used to produce transmission, be used to calculate the device of the interval duration between the transmission in succession, and be used to make the emission function relevant with the frequency of operation of local timing device at random or the pseudorandom time interval in the device of working.
Local timing device preferably has the oscillator of transmitter of the unspecified clock frequency of relatively large tolerance, and the oscillator of different transmitters tends to move with different frequency like this.
Enabled device can comprise the pseudorandom number generator that is used to generate pseudo random number, be used for counter device, and be used for comparison pseudorandom number generator and the output of counter device and only be used to make the workable device of transmitter when consistent when exporting with the speed relevant counting with oscillator frequency.
Transmitter can be radio-frequency (RF) identification (RF/ID) transponder.Embodying EP494,114A and EP585 in the transponder of " anti-collision agreement " that 132A describes, not necessarily need the identification code difference of each transponder; Transponder can be identical, allows them to be made in a large number dirt-cheap.Advantage of the present invention is, when using a kind of like this anti-collision agreement, the ability of exempting conflict preferably arranged.Yet,, can more easily finish a plurality of transponders of interpretation if in pseudorandom number generator, use unique crystal seed (seed).
The present invention expands operate transmitters to and is commonly used to the method for the integrated circuit of body plan transmitter of the present invention.
The accompanying drawing summary
Fig. 1 is the schematic block diagram according to radio-frequency (RF) repeater of the present invention;
Fig. 2 is the schematic block diagram of the emission control piece among Fig. 1; And
Fig. 3 is the transmission synoptic diagram regularly that shows two transponders or terminal (tag).
Embodiment describes
The purpose of this invention is to provide a plurality of transmitters of being used to increase identification and all sending data to a receiver-the typically probability method and the system of transponder.Though the embodiment that describes below refers to by interrogation excites and passive RF transponder power supply from interrogator that is received, the present invention also can be applied to other system.For example, the present invention also can be used for wherein a plurality of must be from-powered transmitter by the system of a receiver identification, or wherein a plurality of transmitter mat system of using " compensation and retry " algorithm of random delay to broadcast.
The present invention is by making transmitter or transponder with at random or pseudorandom time interval rather than reach this requirement in different time emission with the rule time interval.In addition, by from local timing device, the oscillator of each transponder typically, draw at random or pseudorandom regularly, and strengthen the degree at random of emission in succession from each transponder.Head-end type can be at EP494, the type described in 114A and the EP585,132A, and the whole contents of these files is being hereby incorporated by reference.Sizable tolerance on the frequency of operation of the oscillator of the transponder that nominal is identical has increased the randomness of they transmissions.
Referring now to Fig. 1, schematically shown passive RF transponder on the figure.Transponder has antenna 10, and it receives the energy of the RF interrogating signal that is sent by interrogator, and the part of this energy is converted, so that to capacitor C charging, this electric capacity plays the effect of transponder power supply.Transponder has an oscillator 12 on circuit board, and it is operated on the identical nominal frequency of the transponder identical with other nominal.Yet because the manufacturing tolerance in preferred low cost integrated circuit transponder, the output frequency of oscillator 12 typically has+25% manufacturing tolerance.Output frequency also is subjected to the influence from the supply voltage VDD of capacitor C, and this supply voltage VDD is because near interrogator, antenna direction and other factor, is subjected to the intensity effect of the energy of the interrogating signal that received again.Like this, the frequency of the oscillator that each terminal (tag) has is subjected to very big probabilistic influence, and it depends on manufacturing tolerance and supply voltage, and this voltage itself depends on the RF field intensity of reception again.So the frequency of each oscillator was indefinite, unspecified at terminal operating in the past.
Transponder comprises Nonvolatile memery unit 14, EEPROM typically, the identification code of its storage transponder and for different coding data transmission frequency (bit rate), maximum delay time (Nmax.T) and be used for the pseudorandom time delay circuit crystal seed and to the configuration information of transponder programming.Transponder also comprises output driver 16, and it modulates the load that is added to antenna 10 in the embodiment of this description, thereby, modulated its reflectivity, but it also can be an active transmitter.The operation of control logic circuit 18 control output drivers 16, and in response to from the signal of mission controller circuit 20 from memory cell 14 sense datas, this mission controller circuit 20 will be shown in more detail in Fig. 2.When voltage is added to control logic circuit 18, the initial state that the power supply on the reset circuit 22 starts to being scheduled to control logic circuit 18.
In Fig. 2, show mission controller circuit 20 in greater detail.This circuit comprises sequencer 24, and its receives the clock signal from oscillator 12, from this signal draw one may be lower frequency, to produce " memory read " signal, it and clock signal are added to control logic circuit 18 together." memory read " signal is that the cycle with constant frequency is the consecutive pulses sequence of T.Each such pulse makes control logic circuit 18 give an order to memory cell 14 by " sense command " signal, so that order output is stored in wherein identification code in control logic circuit.Yet this identification code not Be Controlled logical circuit is sent to output driver 16 and is used for transmission, unless mission controller 20 and corresponding " memory read " pulse side by side also output " emission enables " signal give control logic circuit 18.This just occurs in the pseudorandom time interval once in a while, as described below.
The output of sequencer circuit 24 also is added to yard period counter 26, thereby it increases when initial from the identification code output sequence of memory cell 14 each.The sign indicating number period counter never resets, but count down to its maximum count value, and after this it turns back to zero, and counts again.Pseudorandom number generator circuit 28 produces pseudo random number every now and then, and the current output of the output of pseudorandom number generator circuit 28 and sign indicating number period counter 26 is added to comparer 30.No matter when two numbers are compared when equating, comparer 30 provides an output, and this output is above said " emission enables " signal." emission enables " signal also triggers pseudorandom number generator, to produce new pseudo random number.When " emission enables " signal and " memory read " signal became high level simultaneously, the code of being read from memory cell 14 by control logic circuit 18 was output to output driver 16, and is sent out.
Referring now to Fig. 3, compared the transmission of two transponders or terminal one Tag1 and Tag2.The oscillator of the oscillator operating ratio Tag2 of Tag1 what soon.Two oscillators all have been incorporated into identical Nmax, but the particular moment shown on figure, Tag1 is in the period of N1.T, to remain passive (not having emission) pattern, wherein N1 changes with each transmission/quiescent period, (0＜=N＜=Nmax), and Tag 2 remains passive mode in N2.T.Notice that the T of Tag1 and the T of Tag2 are inequality, but the two is subjected to the influence with the same variation of above-mentioned frequency.And, the T1 of any terminal, T2, T3 ..., over time and also out of true is equal owing to each particular terminal supply voltage for TN.Therefore, frequency change is all being arranged between the terminal and between the different time in same terminal.The anti-collision system of Shi Yonging in the present invention, compared with as draw the situation of terminal clock signal in other the RF recognition system from RF carrier frequency (for example) by frequency partition at some, provide the ability of much better release conflict, and realize relatively more cheaply.
The Nmax value is by relatively being determined bit number by comparer 30.Carrying out under the 8 bits situation relatively Nmax=255.Nmax is configured when transponder programming or manufacturing.Tested definitely, for specific Nmax number, in identical RF inquiry field, the transponder that can be read out simultaneously or the number of terminal have actual restriction.If compare the number of the transponder in identical inquiry field with for successfully discerning the time that whole transponders spend, then because the conflict between transponder sends, this time approximately is proportional to the transponder number, till the transponder number reaches Nmax/2.If the transponder number is increased to above this point, then the time that identification terminal spent is increased to this condition apace, and wherein transponder all can not be identified, because all transmissions all lead to a conflict.
Because each different favourable aspect of the design of above-mentioned transponder in the data of each transponder send, obtains very big degree at random, although transponder is programmed with identical Nmax value, and is identical basically.This means that the unique value that may need from a transponder to next transponder to adjust is the transponder identification code.
Those skilled in the art it will be appreciated that the present invention can be used to multiple different system.The variation of local timing device therein is not in the system of inherent characteristic, can such variation be included in the system design.For example, can use a plurality of different crystal-oscillator circuit that moves with each different crystal seeds.Each transmitter can be equipped with different pierce circuits, though it is not important providing unique frequency to one group of transmitter.Alternatively, transmitter can dynamically change the frequency of local timing device by for example switching between pierce circuit.Under identical spirit, its medium frequency depends on that the local timing device of external factor (for example, temperature, incident light) can provide necessary frequency change.
Claims (30)
1. discern the method for a plurality of transmitters, each transmitter sends data to a receiver in some time intervals, comprise by each emission function work was changed from the interval duration between the emission in succession of each transmitter, these time intervals by randomly or pseudorandom ground calculate, and relevant with the frequency of operation of the local timing device of being correlated with of this transmitter.
2. method required for protection in the claim 1 is characterized in that, wherein the time interval changes between maximum duration relevant with the predetermined period number of local timing device and minimum interval.
3. method required for protection in the claim 1 is characterized in that, wherein the frequency of operation of local timing device is indefinite.
4. method required for protection in the claim 1; it is characterized in that; wherein can be by generating pseudo random number; and pseudo random number and output by the counter device of local timing device clock synchronization compared; and only when pseudo random number is consistent with the output of counter device, just make the work of emission function, and calculate the interval duration between sending.
5. method required for protection in the claim 4 is characterized in that, wherein pseudo random number is produced periodically.
6. recognition system, comprise a plurality of transmitters, each transmitter is suitable for sending in some time intervals, with at least one receiver, be used to receive emission from transmitter, each transmitter comprises the device that is used to produce transmission, is used to calculate the device of the interval duration between the transmission in succession, and be used to make the emission function relevant with the frequency of operation of local timing device at random or the pseudorandom time interval in the device of working.
7. recognition system required for protection in the claim 6 is characterized in that, wherein calculation element changed in the maximum duration relevant with the predetermined period number of local timing device and the time interval between the minimum interval.
8. recognition system required for protection in the claim 6 is characterized in that, wherein local timing device is an oscillator.
9. recognition system required for protection in the claim 8 is characterized in that, wherein the clock frequency of each oscillator has relatively large tolerance.
10. recognition system required for protection in the claim 8 is characterized in that, wherein the oscillator of different transmitters tends to move with different frequency.
11. recognition system required for protection is characterized in that in the claim 8, wherein the frequency of operation of transmitter is indefinite.
12. recognition system required for protection is characterized in that in the claim 6, wherein calculation element comprises the pseudorandom number generator that is used to generate pseudo random number, with the counter device that is used for counting with the speed relevant with the frequency of local timing device.
13. recognition system required for protection in the claim 12; it is characterized in that; wherein enabled device compares the output of the output of pseudorandom number generator and counter, and only when pseudo random number is consistent with the output of counter device, just makes the work of emission function.
14. recognition system required for protection is characterized in that in the claim 13, wherein pseudo random number produces periodically.
15. be suitable for the transmitter that in some time intervals, sends, comprise the device that is used to produce transmission, be used to calculate the device of the interval duration between the transmission in succession, and be used to make the emission function relevant with the frequency of operation of local timing device at random or the pseudorandom time interval in the device of working.
16. transmitter required for protection is characterized in that in the claim 15, wherein calculation element changed in the maximum duration relevant with the predetermined period number of local timing device and the time interval between the minimum interval.
17. transmitter required for protection is characterized in that in the claim 15, wherein local timing device is an oscillator.
18. transmitter required for protection is characterized in that in the claim 17, wherein the clock frequency of oscillator has relatively large tolerance.
19. transmitter required for protection is characterized in that in the claim 15, wherein calculation element comprises the pseudorandom number generator that is used to generate pseudo random number, with the counter device that is used for counting with the speed relevant with the frequency of local timing device.
20. transmitter required for protection in the claim 19; it is characterized in that; wherein enabled device compares the output of the output of pseudorandom number generator and counter, and only when pseudo random number is consistent with the output of counter device, just makes the work of emission function.
21. transmitter required for protection is characterized in that in the claim 20, wherein pseudo random number produces periodically.
22. in the time interval at random, produce the method that sends from transmitter, comprise by make the work of emission function change interval duration between the transmission in succession of each transmitter in such some time intervals, these time intervals by randomly or pseudorandom ground calculate, and relevant with the frequency of operation of the local timing device of being correlated with of this transmitter.
23. method required for protection is characterized in that in the claim 22, wherein the time interval changes between maximum duration relevant with the predetermined period number of local timing device and minimum interval.
24. method required for protection in the claim 22; it is characterized in that; wherein can be by generating pseudo random number; and pseudo random number and output by the counter device of local timing device clock synchronization compared; and only when pseudo random number is consistent with the output of counter device, just make the work of emission function, and calculate the interval duration between sending.
25. method required for protection is characterized in that in the claim 24, wherein pseudo random number is produced periodically.
26. the integrated circuit that in transmitter, uses, this transmitter comprises local timing device, be used to calculate the device of the interval duration between the transmission in succession, and be used to make the emission function relevant with the frequency of operation of local timing device at random or the pseudorandom time interval in the device of working.
27. integrated circuit required for protection is characterized in that in the claim 25, wherein local timing device is an oscillator.
28. integrated circuit required for protection is characterized in that in the claim 27, wherein the clock frequency of oscillator has relatively large tolerance.
29. integrated circuit required for protection is characterized in that in the claim 25, wherein calculation element comprises the pseudorandom number generator that is used to generate pseudo random number, with the counter device that is used for counting with the speed relevant with the frequency of local timing device.
30. integrated circuit required for protection in the claim 29; it is characterized in that; wherein enabled device compares the output of the output of pseudorandom number generator and counter, and only when pseudo random number is consistent with the output of counter device, just makes the work of emission function.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ZA959519 | 1995-11-09 | ||
| ZA95/9519 | 1995-11-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1201540A true CN1201540A (en) | 1998-12-09 |
Family
ID=25585411
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN96198155A Pending CN1201540A (en) | 1995-11-09 | 1996-11-08 | Enhanced detection of multiple data transmissions |
Country Status (11)
| Country | Link |
|---|---|
| EP (1) | EP0859989A1 (en) |
| JP (1) | JP2000500932A (en) |
| KR (1) | KR19990067371A (en) |
| CN (1) | CN1201540A (en) |
| AR (1) | AR002220A1 (en) |
| AU (1) | AU7502396A (en) |
| BR (1) | BR9611705A (en) |
| CA (1) | CA2235585A1 (en) |
| MX (1) | MX9803671A (en) |
| TW (1) | TW383527B (en) |
| WO (1) | WO1997017667A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100557658C (en) * | 2004-01-12 | 2009-11-04 | 贝扎德·B·莫赫比 | Short-distance cellular booster |
| CN101604021B (en) * | 2009-07-09 | 2012-05-09 | 复旦大学 | Positioning method and device for a radio frequency identification system |
| CN1979532B (en) * | 2005-12-07 | 2012-08-15 | 高菲欧股份有限公司 | Printed radio frequency identification(RFID) tag using tags-talk-first(TTF) protocol |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2333623B (en) * | 1998-01-24 | 2000-04-26 | Plessey Telecomm | Transaction system |
| GB2335573B (en) | 1998-03-18 | 2000-03-15 | Univ Singapore | An RF transponder identification system and protocol |
| GB2344257A (en) | 1998-11-26 | 2000-05-31 | Innovision Research And Techno | Data communication apparatus and board game |
| JP3001570B1 (en) | 1999-02-22 | 2000-01-24 | 埼玉日本電気株式会社 | Adaptive antenna directivity control method and system |
| JP2003500975A (en) * | 1999-05-21 | 2003-01-07 | ケーナー，ラルフ・ジェイ | Identification system for monitoring the presence / absence of members of a defined set |
| AU2001264504A1 (en) * | 2000-06-12 | 2001-12-24 | Telefonaktiebolaget Lm Ericsson (Publ) | Random identity management in scatternets |
| KR100486754B1 (en) * | 2000-08-31 | 2005-05-03 | 매그나칩 반도체 유한회사 | Radio Frequency Identification Tag System for preventing collision and collision preventing method thereof |
| FR2833724A1 (en) | 2001-12-13 | 2003-06-20 | Canal Plus Technologies | DIGITAL ELECTRONIC COMPONENT PROTECTED AGAINST ELECTRICAL AND / OR ELECTROMAGNETIC ANALYZES, ESPECIALLY IN THE FIELD OF CHIP CARDS |
| GB0213724D0 (en) * | 2002-06-14 | 2002-07-24 | Turner Christopher G G | Electronic identification system |
| WO2006079972A1 (en) * | 2005-01-31 | 2006-08-03 | Nxp B.V. | Improved communication between a communication station and data carriers |
| KR100749818B1 (en) * | 2005-09-23 | 2007-08-17 | 한국전자통신연구원 | Multitag Recognition Apparatus and Method in Rfid System |
| DE602007006902D1 (en) | 2007-02-07 | 2010-07-15 | Albis Technologies Ag | Transmission protocol for opening a dynamic window for data reception |
| KR20120011602A (en) * | 2010-07-29 | 2012-02-08 | 삼성테크윈 주식회사 | Communication control method of RFID reader |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4471345A (en) * | 1982-03-05 | 1984-09-11 | Sensormatic Electronics Corporation | Randomized tag to portal communication system |
| FR2667715A1 (en) * | 1990-10-09 | 1992-04-10 | Gemplus Card Int | METHOD AND DEVICE FOR INCREASING THE PROTECTION OF A MEMORY CARD. |
| US5530702A (en) * | 1994-05-31 | 1996-06-25 | Ludwig Kipp | System for storage and communication of information |
-
1996
- 1996-11-07 TW TW085113603A patent/TW383527B/en active
- 1996-11-08 JP JP9517995A patent/JP2000500932A/en active Pending
- 1996-11-08 WO PCT/GB1996/002742 patent/WO1997017667A1/en not_active Application Discontinuation
- 1996-11-08 KR KR1019980703381A patent/KR19990067371A/en not_active Application Discontinuation
- 1996-11-08 CA CA 2235585 patent/CA2235585A1/en not_active Abandoned
- 1996-11-08 CN CN96198155A patent/CN1201540A/en active Pending
- 1996-11-08 BR BR9611705A patent/BR9611705A/en unknown
- 1996-11-08 AU AU75023/96A patent/AU7502396A/en not_active Abandoned
- 1996-11-08 AR ARP960105103A patent/AR002220A1/en unknown
- 1996-11-08 EP EP96937429A patent/EP0859989A1/en not_active Withdrawn
-
1998
- 1998-05-08 MX MX9803671A patent/MX9803671A/en unknown
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100557658C (en) * | 2004-01-12 | 2009-11-04 | 贝扎德·B·莫赫比 | Short-distance cellular booster |
| CN1979532B (en) * | 2005-12-07 | 2012-08-15 | 高菲欧股份有限公司 | Printed radio frequency identification(RFID) tag using tags-talk-first(TTF) protocol |
| CN101604021B (en) * | 2009-07-09 | 2012-05-09 | 复旦大学 | Positioning method and device for a radio frequency identification system |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0859989A1 (en) | 1998-08-26 |
| AU7502396A (en) | 1997-05-29 |
| CA2235585A1 (en) | 1997-05-15 |
| BR9611705A (en) | 1999-02-23 |
| TW383527B (en) | 2000-03-01 |
| WO1997017667A1 (en) | 1997-05-15 |
| MX9803671A (en) | 1998-09-30 |
| JP2000500932A (en) | 2000-01-25 |
| AR002220A1 (en) | 1998-03-11 |
| KR19990067371A (en) | 1999-08-16 |
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