CN101112009A - RFID carrier wave interception method and RFID system adopting the same - Google Patents
RFID carrier wave interception method and RFID system adopting the same Download PDFInfo
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Abstract
There is provided a RFID system capable of increasing the probability to detect an empty channel and reduce the affect of the interference between readers/writers. The RFID system includes: a reader/writer having a reader/writer main body and an antenna capable of switching polarization for transmitting a continuous carrier; and a tag for modulating the continuous carrier by tag information and returning a response signal to the reader/writer. The reader/writer main body judges the level of the interference signal received, decides the channel and the polarization direction for making the interference signal level below a threshold value, and receives the response signal from the tag by the decided channel and the polarization direction.
Description
Technical field
The present invention relates to a kind of Radio Frequency ID (RFID: radio-frequency (RF) identification) carrier sensing method and the RFID reader/writer and the rfid system that utilize Radio Frequency ID.
Background technology
In recent years, aspect the id information of reading and recording on label, developed the system that the magnetic coupling of having used utilization and label reads or used wireless frequency to come the rfid system of reading tag information.
For the latter's the rfid system that utilizes wireless frequency to read, as example, ETSI (ETSI) (Draft ETSI EN 302 208-1V1.1.1 (2003-12)) discloses European standard.Disclosing maximum power in Draft ETSI EN 302 208-1V1.1.1 (2003-12) is the use of the rfid system that utilizes 865MHz to 868MHz frequency band of 2W.
Here, thus have the situation that a plurality of reader/writers move located adjacent one anotherly becomes a rfid system.Fig. 1 shows the example of this state.
In Fig. 1, the signal that is sent by corresponding reader/writer #1 (#2) has interference 3 to another reader/writer #2 (#1), thereby has the problem of the receptivity deterioration of reader/writer # 1 and #2.In order to address this problem, before sending, to carry out carrier sense and disturb 3 influence, and the current channel that is not used by other reader/writers #2 (#1) is searched for to reduce.In addition, adopted following method:, then use idle channel if there is idle channel; If there is no idle channel is then waited for till finding idle channel.
In other words, Fig. 2 shows the method that adopts this carrier sense.Fig. 2 is the read operation flow chart to label information of the individual reader/writer among Fig. 1.
According to Fig. 2, each among reader/writer # 1 and the #2 all is made of 1a of reader portion and antenna 1b.
At first, set initial channel (frequency bandwidth) (step S1) by the 1a of reader portion, measure then utilize the carrier wave that antenna 1b receives in the initial channel of setting like this level as interference signal (step S2).If the level of this interference signal then can not use this channel greater than threshold value (step S3, not), therefore, with the interference level of other channels as measurement target.In other words, judge the measurement whether carried out all channels, (step S4, not), then switching channels (step S5) is sequentially measured (step S2) to be back to same interference level if there is the channel measured as yet.
Under having carried out (step S4 is) to the situation of the measurement of all channels, set the stand-by period (step S6) at random, being back to initial channel setting (step S1) once more, repeat this processing then through handling after the stand-by period that sets.
If interference level is equal to or less than threshold value (step S3 is) in interference level measurement (step S2), determined that then interference level is equal to or less than the channel of described threshold value (step S7), sends command signal (step S8) then.
Fig. 3 shows by the command signal of the antenna 1b of reader/writer #1 (#2) emission with from the answer signal of label 2a (2b).As shown in Figure 3A, reader/writer # 1 and #2 send unmodulated continuous wave CW, and by command signal this unmodulated continuous wave CW are modulated, thereby for example utilize fixing right-hand circular polarization to send this continuous wave CW by antenna 1b.
When corresponding reader/writer # 1 and #2 receive command signal, label 2a and 2b are used under the identification label characteristic information of the information (ID) of article and are used as label information unmodulated continuous carrier CW is modulated by comprising, and reply (referring to step S9: Fig. 3 B).Reader/writer # 1 receives this answer signal and finishes to communicate by letter (step S10) with #2.
In addition, employed another kind of method is such method, and according to this method, a plurality of reader/writer # 1 of control device centralized control and #2 and the transmission of controlling each reader/writer are regularly.
The last method of carrying out according to the flow process of Fig. 2, promptly relate to and carry out aforesaid carrier sense: have a large amount of reader/writers, and the stand-by period is long to search for the current channel that is not used by other reader/writers and to use the method for this idle channel to be faced with such problem under the situation of idle channel existing.In addition, relating under the situation of carrying out central controlled back one method by control device, when having a large amount of reader/writers, there is the short problem of call duration time of distributing.
Summary of the invention
Therefore, even the transmission that also can eliminate each reader/writer when the objective of the invention is in rfid system, to exist a plurality of reader/writer regularly the stand-by period long or distribute to the short problem of call duration time of these reader/writers, and be to reduce the mutual interference effect that when a plurality of reader/writers are located adjacent one another, occurs.
As first aspect, a kind of rfid system that addresses the above problem is provided, it has: reader/writer, it has reader portion and can carry out the antenna that polarization switches, and it sends continuous carrier; And label, it uses label information that described continuous carrier is modulated, and answer signal sent it back described reader/writer, wherein, the level of the interference signal that is received is judged by described reader portion, determine that the described level of described interference signal is equal to or less than the channel and the polarization direction of threshold value, and receive described answer signal from described label by determined channel and polarization direction.
According to second aspect, be configured to: describedly can carry out the antenna that polarization switches and between right-hand circular polarization and Left-hand circular polarization, to switch according to the rfid system that addresses the above problem of first aspect; And the interference signal that will receive detects in described reader portion under the situation of right-hand circular polarization or Left-hand circular polarization level is equal to or less than the channel of described threshold value.
According to the third aspect, be configured to: describedly can carry out the antenna that polarization switches and between horizontal polarization and vertical polarization, to switch according to the rfid system that addresses the above problem of first aspect; And the interference signal that will receive detects in described reader portion under the situation of horizontal polarization or vertical polarization level is equal to or less than the channel of described threshold value.
According to fourth aspect, the described rfid system that addresses the above problem has: reader/writer, and a plurality of antennas that it has reader portion and has the feature polarization separately, and it sends continuous carrier; And label, it uses label information that described continuous carrier is modulated, and answer signal sent it back described reader/writer, wherein, the level of the interference signal that will be received by each antenna in described a plurality of antennas is judged by described reader portion at each channel in a plurality of channels, determine that the level of the described interference signal judged is equal to or less than the idle channel and the antenna of threshold value, and receive described answer signal by determined antenna from described label via determined channel.
According to the 5th aspect, the described rfid system that addresses the above problem is that wherein, described channel is each band that is divided into the frequency band of a plurality of bandwidth according to the rfid system of first aspect either side to the fourth aspect.
According to the 6th aspect, the described rfid system that addresses the above problem is the rfid system according to first aspect either side to the fourth aspect, wherein, described label is made of paster antenna and LSI, described LSI and described paster antenna are connected in parallel and have interface portion, and described interface portion has the capacitance component with Inductive component generation resonance.
A kind of carrier sensing method of the rfid system that addresses the above problem is the carrier sensing method of such rfid system, this rfid system has with regard to first aspect: reader/writer, it has reader portion and can carry out the antenna that polarization switches, and it sends continuous carrier; And label, it uses label information that described continuous carrier is modulated, and answer signal sent it back described reader/writer, described method has following steps: in described reader/writer, all polarizations that can switch at described antenna utilize particular channel sequentially to measure interference signal level; When the interference signal level that will measure during,, described particular channel measures described interference signal level by being switched to other channels greater than threshold value; Determine that the described interference signal level that records does not so surpass the channel and the polarization direction of described threshold value; And set for and receive the continuous carrier that utilizes described label information modulation that sends it back from described label via determined channel and with determined day linear polarization.
The described carrier sensing method of the rfid system that addresses the above problem is the carrier sensing method of such rfid system, this rfid system has with regard to second aspect: reader/writer, it has reader portion and a plurality of antennas that are respectively arranged with different polarization directions, and it sends continuous carrier; And label, it uses label information that described continuous carrier is modulated, and answer signal sent it back described reader/writer, described method has following steps: in described reader/writer, at each polarization of described a plurality of antennas, utilize particular channel sequentially to measure interference signal level; When the interference signal level that will measure during,, described particular channel measures described interference signal level by being switched to other channels greater than threshold value; Determine to be set to the described interference signal level that records like this and do not surpass the channel of described threshold value and the antenna of polarization direction; And set for and utilize determined channel and antenna to receive described answer signal from described label.
The first aspect of the reader/writer that addresses the above problem is a kind ofly to have reader portion and can carry out antenna that polarization switches and send continuous carrier to label, the reader/writer of rfid system, wherein, judge the level of the interference signal that is received, and the described level of determining described interference signal is equal to or less than the channel and the polarization direction of the described antenna of threshold value, and on determined channel and with determined polarization direction, receive answer signal, this answer signal utilizes label information that described continuous carrier is modulated and produced, and is sent by described label.
The second aspect of the reader/writer that addresses the above problem is a kind ofly to have reader portion and have a plurality of antennas of feature polarization separately and send continuous carrier to label, the reader/writer of rfid system, wherein, the level of the interference signal that will be received by each antenna in described a plurality of antennas is judged by described reader portion at each channel in a plurality of channels, determine that the level of the described interference signal judged is equal to or less than the idle channel and the antenna of threshold value, and receive answer signal by determined antenna via determined channel, this answer signal utilizes label information that described continuous carrier is modulated and produced, and is sent by described label.
By the preferred implementation that will describe according to following accompanying drawing, it is more obvious that feature of the present invention will become.
The invention enables that to detect the idle channel probability high and can reduce interference effect between the reader/writer.
Description of drawings
Thereby Fig. 1 has described the example states that a plurality of reader/writers move the situation that becomes a rfid system located adjacent one anotherly;
Fig. 2 has described the idle channel detection method of using carrier sense;
Fig. 3 has described by the command signal of the antenna 1b of reader/writer #1 (#2) emission with from the answer signal of label 2a (2b);
Thereby Fig. 4 shows the present invention and moves feature under the situation that becomes a rfid system at a plurality of reader/writer # 1 and #2 located adjacent one anotherly;
Fig. 5 is a concept map of having used the formation embodiment of reader/writer of the present invention;
Fig. 6 is the concept map of the formation embodiment of another reader/writer;
Fig. 7 is the conceptual schema of the execution mode of label 2a (2b);
Fig. 8 is based on the operating process of the embodiments of the present invention of reader/writer and label configurations prerequisite;
Fig. 9 shows by the command signal of the antenna 1b of reader/writer #1 (#2) emission with from the answer signal of label 2a (2b);
Figure 10 shows polarization direction 1 to n that the execution mode flow process of utilizing Fig. 8 determines and the relation between the channel Ch1 to Ch4; And
Figure 11 shows the execution mode that uses a plurality of antennas, has all set particular polarization at each antenna.
Embodiment
Below embodiments of the present invention will be described with reference to the accompanying drawings.The execution mode that describes below makes the present invention be able to be understood, and technical scope of the present invention is not limited thereto.
Fig. 4 shows a plurality of reader/writer # 1 and thereby #2 moves the situation that becomes a rfid system located adjacent one anotherly, and compared to Figure 1, when carrier sense is feature of the present invention, provide the function 4 of the polarization direction of the antenna 1b that controls reader/writer.
Fig. 5 is a concept map of having used the formation embodiment of reader/writer # 1 of the present invention and #2.
In Fig. 5, antenna 1b comprises antenna element 10 and polarization direction control part 20.Polarization direction control part 20 shown in Fig. 5 has the function that the polarization direction of antenna element 10 is switched to right-hand circular polarization and Left-hand circular polarization.Antenna element 10 comprises the dipole antenna of two quadratures, and horizontal doublet antenna is connected to switch 15, and vertical dipoles is connected to switch 16.
The 1a of reader portion transmits transmission signal TXSIG to the transmission/reception diverter switch 14 of polarization direction control part 20, and input is from the received signal TRSIG of transmission/reception diverter switch 14.In addition, the 1a of reader portion sends polarization switching signal PWSW to the switch control part 11 of polarization direction control part 20.
Two hybrid circuits 12 and 13 all have to the transmission signal TXSIG of its input and through the output signal of 0 ° and 90 ° phase shift.Switch control part 11 is controlled switching to switch 14,15 and 16 according to the polarization switching signal PWSW from the 1a of reader portion.
In other words, when the 1a of reader portion when switch control part 11 has sent the polarization switching signal PWSW that specifies right-hand circular polarization, switch control part 11 provides the lead-out terminal o1 that makes switch 14 and the effective switch switching signal of input terminal I1 of switch 15 and 16 to switch 14,15 and 16.
On the contrary, when reader/writer # 1 when switch control part 11 has sent the polarization switching signal PWSW that specifies Left-hand circular polarization, switch control part 11 provides the lead-out terminal o2 that makes switch 14 and the effective switch switching signal of input terminal I2 of switch 15 and 16 to switch 14,15 and 16.
Therefore, when providing 0 ° of phase shift signal to the horizontal doublet antenna element of antenna 10 by switch 15, and by switch 16 when the vertical dipoles element of antenna 10 provides 90 ° of phase shift signals, produce right-hand circular polarization.On the contrary, when providing 90 ° of phase shift signals to the horizontal doublet antenna element of antenna 10 by switch 15, and by switch 16 when the vertical dipoles element of antenna 10 provides 0 ° of phase shift signal, produce Left-hand circular polarization.
Fig. 6 is the concept map of the formation embodiment of another reader/writer, and this reader/writer comprises the function that switch the polarization direction that is used for control antenna 10 between horizontal polarization and vertical polarization.
In Fig. 6, the same with execution mode among Fig. 5, antenna 1b comprises antenna element 10 and polarization direction control part 20.The 1a of reader portion transmits transmission signal TXSIG to the transceiver diverter switch 14 of polarization direction control part 20, and by transceiver diverter switch 14 input received signal TRSIG.In addition, the 1a of reader portion is to the switch control portion 11 transmission levels and the vertical polarization switching signal PWSW of polarization direction control part 20.
When the 1a of reader portion when switch control part 11 has sent the polarization switching signal PWSW of specified level polarization, switch control part 11 makes the lead-out terminal o1 of switch 14 effective, provides polarization switching signal PWSW with the horizontal doublet antenna element to antenna 10.On the contrary, when the 1a of reader portion when switch control part 11 has sent the polarization switching signal PWSW that specifies vertical polarization, switch control part 11 makes the lead-out terminal o2 of switch 14 effective, provides this polarization switching signal PWSW with the vertical dipoles element to antenna 10.
Therefore, in execution mode shown in Figure 6, can also can only constitute antenna 10 based on the polarization direction of antenna 10 being switched to level or vertical from the polarization switching signal PWSW of the 1a of reader portion by structure shown in Figure 5.
Fig. 7 is the conceptual schema of the execution mode of label 2a (2b).Label 2a (2b) is made of antenna part 30 and LSI chip 31.As embodiment, antenna part 30 is made of paster antenna, and has the inductance L as equivalent electric circuit.LSI chip 31 has capacitance component C in interface portion.
The interface portion of LSI chip 31 and antenna part 30 is connected in parallel.Therefore, if the capacitance component C of the inductance L of antenna part 30 and interface portion has the resonance relation, then can receive the continuous wave CW that sends by reader/writer, and this continuous wave CW can be offered the control part CONT of LSI chip 31 with maximum power.
The control part CONT of LSI chip 31 is according to the power that is provided, by comprising the characteristic information that the relevant identifying information of the commodity of label annex is arranged with preparation, CW modulates to continuous wave, can launch the modulated continuous wave CW that obtain to reader/writer along fixing polarization direction (for example, horizontal direction) from antenna part 30 thus.
Now, will operating process according to an embodiment of the present invention based on this reader/writer and label configurations prerequisite be described according to Fig. 8.
In Fig. 8, at first in the 1a of reader portion, carry out the setting (step S1) of initial channel (frequency band), set initial antenna polarization (step S11) then.Now, as the front described in the execution mode of Fig. 5, when initial antenna polarization was right-hand circular polarization, switch control part 11 made the lead-out terminal o1 of switch 14 effective, and made the input terminal I1 of 0 ° of phase shift lead-out terminal of hybrid circuit 12 and switch 15 effective.Similarly, it is effective that switch control part 11 makes the input terminal I1 of 90 ° of phase shift lead-out terminals of hybrid circuit 12 and switch 16.
Under the situation of this set, the level of measuring the carrier wave that is received by antenna 10 is as interference signal (step S2).(step S3 not), then can not use this channel if interference signal level is greater than threshold value.
So, judge as yet the polarization direction of execution measurement (being the Left-hand circular polarization direction in this case) (step S12) in the situation that does not change channel, and the sky linear polarization switched to Left-hand circular polarization direction (step S13).Therefore, on the polarization direction after the switching, continue interference level once more and measure (step S2) processing afterwards.
Therefore, also be like this to the measurement of all polarizations, (step S3 not), then makes the interference level of other channels become measurement target if the level of interference signal is greater than threshold value.In other words, if judge the measurement carried out all channels, and if exist carry out as yet the channel measured (step S4, not), switching channels (step S5) sequentially then, and handle and be back to same interference level and measure (step S2).
Under having carried out (step S4 is) to the situation of the measurement of all channels, set the stand-by period (step S6) at random, through after the stand-by period that sets, handle being back to initial channel once more and setting (step S1), and repeat above-mentioned processing.
In addition, if interference level is equal to or less than threshold value (step S3 in interference level measurement (step S2), be), determined that then interference level is equal to or less than the use channel and day linear polarization (step S7) of threshold value, and sent command signal (step S8).
Here, Fig. 9 shows by the command signal of the antenna 1b of reader/writer #1 (#2) emission and from the answer signal of label 2a (2b).
Shown in Fig. 9 A, reader/writer # 1 and #2 (for example adopt determined use channel and day linear polarization, right-hand circular polarization), continuous wave CW is modulated preamble Pre and checking signal CRC that this frame signal has command signal and lays respectively at these command signal front and back by frame signal.
Shown in Fig. 9 B, when label 2a and 2b when corresponding reader/writer # 1 and #2 receive command signal, the characteristic information and the identifying information of the article by will having label are used as label information, by having the preamble Pre that is positioned at before and after it and the frame signal of checking signal CRC equally, CW modulates to continuous wave, thus to corresponding reader/writer # 1 and #2 reflection continuous wave CW.
Reader/writer # 1 receives this answer signal and finishes to communicate by letter (step S10) with #2.
Figure 10 shows channel Ch1 to Ch4 that the flow process of the execution mode that utilizes Fig. 8 determines and the relation between the polarization direction 1 to n.In Figure 10, the shadow region represents that interference signal level is equal to or less than threshold value and can uses the situation of corresponding channel (frequency bandwidth) and polarization in reader/writer.
In addition, though in the superincumbent description illustration reader/writer structure that has an antenna 1b and the polarization direction of antenna is switched, application of the present invention is not limited to this structure or is not subjected to the restriction of this structure.In other words, as shown in figure 11, following structure also is possible: a plurality of antenna 101b to 10nb that wherein will set particular polarization separately are connected to the 1a of reader portion, and select to control so that effective corresponding to the specific antenna of the polarization of being set by the 1a of reader portion.
In addition, in Figure 11, with regard to the polarization direction of each antenna among a plurality of antenna 101b to 10nb as described in can controlling changeably as Fig. 5 or ground shown in Figure 6, can utilize less sky line search to allow the channel of free communication.
Utilizability on the industry
As mentioned above, although in traditional method, this structure only with fixing polarization to available letter The road is searched for, but according to the present invention, utilizes the combination of channel and polarization direction to interfering signal Level is equal to or less than the state of threshold value and searches for. According to the described feature of this structure, can Provide and make the probability that detects idle channel higher and reduced interference between the reader/writer The rfid system of impact. Therefore, the present invention has very big contribution to industry.
The application is in the continuity application of the International Application PCT/JP2005/001319 of submission on January 31st, 2005.
Claims (16)
1. rfid system, this rfid system comprises:
Reader/writer, it has reader portion and can carry out the antenna that polarization switches, and it sends continuous carrier; With
Label, it uses label information that described continuous carrier is modulated, and answer signal is sent it back described reader/writer,
Wherein, the level of the interference signal that is received is judged by described reader portion, determine that the described level of described interference signal is equal to or less than the channel and the polarization direction of threshold value, and receive described answer signal from described label by determined channel and polarization direction.
2. rfid system according to claim 1, wherein,
The described antenna that can carry out the polarization switching can switch between right-hand circular polarization and Left-hand circular polarization; And
The interference signal that will receive detects in described reader portion under the situation of right-hand circular polarization or Left-hand circular polarization level is equal to or less than the channel of described threshold value.
3. rfid system according to claim 1, wherein,
The described antenna that can carry out the polarization switching can switch between horizontal polarization and vertical polarization; And
The interference signal that will receive detects in described reader portion under the situation of horizontal polarization or vertical polarization level is equal to or less than the channel of described threshold value.
4. rfid system, this rfid system comprises:
Reader/writer, a plurality of antennas that it has reader portion and has the feature polarization separately, and it sends continuous carrier; With
Label, it uses label information that described continuous carrier is modulated, and answer signal is sent it back described reader/writer, wherein,
The level of the interference signal that will be received by each antenna in described a plurality of antennas is judged by described reader portion at each channel in a plurality of channels, determine that the level of the described interference signal judged is equal to or less than the channel and the antenna of threshold value, and receive described answer signal by determined antenna from described label via determined channel.
5. according to claim 1 or 4 described rfid systems, wherein, described channel is each band that is divided into the frequency band of a plurality of bandwidth.
6. according to claim 1 or 4 described rfid systems, wherein, described label is made of paster antenna and LSI, and described LSI and described paster antenna are connected in parallel and have interface portion, and described interface portion has the capacitance component with Inductive component generation resonance.
7. the carrier sensing method of a rfid system, described rfid system has: reader/writer, it has reader portion and can carry out the antenna that polarization switches, and it sends continuous carrier; And label, it uses label information that described continuous carrier is modulated, and answer signal is sent it back described reader/writer,
Said method comprising the steps of: in described reader/writer,
All polarizations that can switch at described antenna utilize particular channel sequentially to measure interference signal level;
When the interference signal level that will measure during,, described particular channel measures described interference signal level by being switched to other channels greater than threshold value;
Determine that the described interference signal level that records does not so surpass the channel and the polarization direction of described threshold value; And
Set on determined channel and receive described answer signal from described label with determined day linear polarization.
8. the carrier sensing method of rfid system according to claim 7, wherein,
The described antenna that can carry out the polarization switching can switch between right-hand circular polarization and Left-hand circular polarization; And
The interference signal that will receive detects in described reader portion under the situation of right-hand circular polarization or Left-hand circular polarization level is equal to or less than the channel of described threshold value.
9. the carrier sensing method of rfid system according to claim 7, wherein,
The described antenna that can carry out the polarization switching can switch between horizontal polarization and vertical polarization; And
The interference signal that will receive detects in described reader portion under the situation of horizontal polarization or vertical polarization level is equal to or less than the channel of described threshold value.
10. the carrier sensing method of a rfid system, described rfid system has: reader/writer, it has reader portion and a plurality of antennas that are respectively arranged with different polarization directions, and it sends continuous carrier; And label, it uses label information that described continuous carrier is modulated, and answer signal is sent it back described reader/writer,
Said method comprising the steps of: in described reader/writer,
At each polarization of described a plurality of antennas, utilize particular channel sequentially to measure interference signal level;
When the interference signal level that will measure during,, described particular channel measures described interference signal level by being switched to other channels greater than threshold value;
Determine to be set to the described interference signal level that records like this and do not surpass the channel of described threshold value and the antenna of polarization direction; And
Set for and utilize determined channel and antenna to receive described answer signal from described label.
11. according to claim 7 or 10 described rfid systems, wherein, described channel is each band that is divided into the frequency band of a plurality of bandwidth.
12. according to claim 7 or 10 described rfid systems, wherein, described label is made of paster antenna and LSI, described LSI and described paster antenna are connected in parallel and have interface portion, and described interface portion has the capacitance component with Inductive component generation resonance.
13. the reader/writer of a rfid system, described reader/writer have reader portion and can carry out the antenna that polarization switches, and send continuous carrier to label, wherein,
Judge the level of the interference signal that is received, and determine that the described level of described interference signal is equal to or less than the channel and the polarization direction of the described antenna of threshold value, and
Receive answer signal on determined channel and with determined polarization direction, this answer signal utilizes label information that described continuous carrier is modulated and produced, and is sent by described label.
14. reader/writer according to claim 13, wherein,
The described antenna that can carry out the polarization switching can switch between right-hand circular polarization and Left-hand circular polarization; And
The interference signal that will receive detects in described reader portion under the situation of right-hand circular polarization or Left-hand circular polarization level is equal to or less than the channel of described threshold value.
15. reader/writer according to claim 13, wherein,
The described antenna that can carry out the polarization switching can switch between horizontal polarization and vertical polarization; And
The interference signal that will receive detects in described reader portion under the situation of horizontal polarization or vertical polarization level is equal to or less than the channel of described threshold value.
16. the reader/writer of a rfid system, described reader/writer have reader portion and have a plurality of antennas of feature polarization separately, and send continuous carrier to label, wherein,
The level of the interference signal that will be received by each antenna in described a plurality of antennas is judged by described reader portion at each channel in a plurality of channels, determine that the level of the described interference signal judged is equal to or less than the channel and the antenna of threshold value, and receive answer signal by determined antenna via determined channel, this answer signal utilizes label information that described continuous carrier is modulated and produced, and is sent by described label.
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| CN105916102A (en) * | 2016-05-25 | 2016-08-31 | 桂林电子科技大学 | Multi-RFID tag simultaneous reading method based on non-orthogonal multiple access |
| CN107107629A (en) * | 2014-10-13 | 2017-08-29 | 艾利丹尼森零售信息服务公司 | Reduce the separation of inlay spacing |
| US10073994B2 (en) | 2014-10-13 | 2018-09-11 | Avery Dennison Retail Information Services, Llc | Successive memory writes in an RFID interrogator |
| CN112261687A (en) * | 2020-10-22 | 2021-01-22 | 北京计算机技术及应用研究所 | Air interface signal interference detection method for ultrahigh frequency RFID system |
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2005
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US10073994B2 (en) | 2014-10-13 | 2018-09-11 | Avery Dennison Retail Information Services, Llc | Successive memory writes in an RFID interrogator |
| CN107107629B (en) * | 2014-10-13 | 2019-12-24 | 艾利丹尼森零售信息服务公司 | Method and apparatus for RFID devices |
| US10592794B2 (en) | 2014-10-13 | 2020-03-17 | Avery Dennison Retail Information Services, Llc | Industrial printer |
| US10599887B2 (en) | 2014-10-13 | 2020-03-24 | Avery Dennison Retail Information Services, Llc | Dual RFID modules in an RFID printer/encoder/verification system |
| US11010571B2 (en) | 2014-10-13 | 2021-05-18 | Avery Dennison Retail Information Services, Llc | Industrial printer |
| US11017188B2 (en) | 2014-10-13 | 2021-05-25 | Avery Dennison Retail Information Services, Llc | Successive memory writes in an RFID interrogator |
| US11521000B2 (en) | 2014-10-13 | 2022-12-06 | Avery Dennison Retail Information Services Llc | Industrial printer |
| CN105916102A (en) * | 2016-05-25 | 2016-08-31 | 桂林电子科技大学 | Multi-RFID tag simultaneous reading method based on non-orthogonal multiple access |
| CN105916102B (en) * | 2016-05-25 | 2019-04-26 | 桂林电子科技大学 | More RFID label tags based on non-orthogonal multiple while read method |
| CN112261687A (en) * | 2020-10-22 | 2021-01-22 | 北京计算机技术及应用研究所 | Air interface signal interference detection method for ultrahigh frequency RFID system |
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