CN1928884A - Multi-address switch-in anti-collision method implemented in circuit shift method - Google Patents
Multi-address switch-in anti-collision method implemented in circuit shift method Download PDFInfo
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- CN1928884A CN1928884A CNA200610096364XA CN200610096364A CN1928884A CN 1928884 A CN1928884 A CN 1928884A CN A200610096364X A CNA200610096364X A CN A200610096364XA CN 200610096364 A CN200610096364 A CN 200610096364A CN 1928884 A CN1928884 A CN 1928884A
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Abstract
The multiple access scheme for RF card comprises: the RF mark generates Gold sequence with some length set by Interrogator; when taking two-phase key control or amplitude key-control to UHF of reading device, using the Gold sequence to modulate and transmit the Tag; on receiving terminal, taking correlation calculation to decide existence of some Tag for RF recognition.
Description
Technical field
The present invention is a kind of radio-frequency card multiple access access scheme that can be applied to radio-frequency (RF) identification, belongs to the REID field in mechanics of communication and the electronic technology.
Background technology
In the evolution of radio-frequency (RF) identification (RFID) technology, the anticollision technology is signal identification and one of gordian technique of handling.When having a plurality of radio-frequency cards to arrive in the antenna area at read write line, they almost send signal simultaneously, produce channel contention, and signal interferes with each other, and collision has promptly taken place.This situation is in the vending system in supermarket, and is very common when a plurality of commodity that have sign are read simultaneously by same fetch equipment.The quality of anticollision technical design has determined the radio-frequency recognition system performance to a great extent.
The common anticollision technology utilization queuing Anti-noise Technique of touching upon solves collision problem, mainly is to realize by the algorithm of evading and retrieve.Though adopt these class methods can make that simplicity of design, the cost of system is low and be easy to revise, the response time is longer relatively, and the real-time that reads process when needing the number of the card that is read bigger at the same time is difficult to guarantee.When for example all in reading the container that moves through at a distance had RFID sign article, because the number of article may be very big, and the limited time that reads, requirement must be read in the sign that the lorry container is finished all article in by the time.Under these circumstances, traditional simple passing through evaded or the RFID collision-proof method of searching algorithm does not just meet the demands.In addition, the system that also has adopts hardware to realize adopting time division multiple access (TDMA) to insert (TDMA), frequency division multiple access access multiple access recognition technologies such as (FDMA), though less time delay can be arranged, system complexity and cost have significantly to be increased.
On the other hand, along with the information that Tag (RFID tag) in the application of RFID is entrained is more and more, data interaction amount between reader and the Tag is increasing, the system-operating environment of RFID also becomes increasingly complex, and rfid system requires also more and more higher to the interference free performance and the security performance of radio communication chain circuit.Therefore, the multiple access that needs a kind of high-level efficiency and have good resistance jamming performance, a security performance inserts and anticollision mechanism.
Summary of the invention
Technical matters: the purpose of this invention is to provide a kind of multiple access access, collision-proof method of realizing with cyclic shift mode, the complexity of this method, cost expense keep in allowed limits, the anticollision performance improves greatly, simultaneously, has code division multiplexing mode signal to noise ratio (S/N ratio) height, strong interference immunity, good confidentiality, the advantage that the anti-multipath interference performance is strong.
Technical scheme: basic thought of the present invention is: radio-frequency (RF) tag generates Goethe's sign indicating number (Gold) sequence of certain-length, and this code length can be provided with by reader (Interrogator) order, can change the consuming time of whole collision recognition by selecting code length.Carry out modulation systems such as two-phase keying or amplitude keying at ultra-high frequency signal when carrying out the reflection modulation Data transmission, adopt this Gold sequence signal that the data that RFID tag (Tag) needs to send are modulated transmission for arrangement for reading.Receiving end at first utilizes the good autocorrelation performance of Gold sequence to carry out related operation, and adjudicates whether there is certain Tag according to result of calculation after the signal demodulation, promptly carries out radio-frequency (RF) identification.
Being interpreted as of all titles in this article:
Tag: RFID tag
RFID: radio-frequency (RF) identification
The M sequence: a kind of specific reflected code formation sequence specially claims " M sequence " in the world
The figure place of initial value in the Q:M sequence generator
Gold: a kind of specific reflected code formation sequence specially claims " Gold sign indicating number " and " Gold sequence " in the world
Interrogator: reader
Query: the querying command of this patent definition
QueryReq: the querying command again of this patent definition
QueryAdjust: the inquiry adjustment order of this patent definition
ACK: the response order of this patent definition
ID: identification number
RN_Nm: the random integers side-play amount that tab end produces
ID_Nm: label according to the choosing method that begins from most significant digit or lowest order, is chosen Q position, the integer of a Q position that is produced in identification number.
The multiple access of realizing with cyclic shift mode of the present invention inserts, collision-proof method is:
1) 22 of Q position initial value have been adopted on the label
QThe structure of-1 M sequence generator addition finally produces 2
Q-1 Gold sequence; The span of Q comprises 4,6,8,10,12, and this Q value is by the reader command queries ' parameter of Query ' selects;
2) label according to the choosing method that begins from most significant digit or lowest order, is chosen Q position in identification number, produces the integer of a Q position, is named as ID_Nm; This choosing method can be revised with order Query by reader; Promptly from the most significant digit of identification number, choose a Q high position, perhaps the lowest order of identification number rises, and chooses Q low level, in addition, makes each label produce one " 0,2
Q-1 " the random integers side-play amount in the scope is named as RN_Nm, and this random number and ID_Nm carry out mould 2
Q-1 addition, the result of generation finally produces the Gold sequence with this label as the initial value of first M sequence generator in the Gold sequence generator of this label; Label uses this Gold sequence that own recognition data to be sent is modulated; This data content comprises: remove the remainder of the Q position of having taken out the front in the own identification number, and the random integers side-play amount RN_Nm that uses previously; Before band spectrum modulation, at first also need to carry out the Miller modulation, purpose is to make data become the bipolarity return-to-zero code of the detection of collision for the benefit of, these data are modulated and send to reader, wait for the response order of reader then, i.e. ACK;
3) the reader signal of accepting the transmission of the label line correlation demodulation of going forward side by side, if do not bump, promptly there is not plural label to produce same Gold sequence, though collision has perhaps taken place, but reader is still differentiated the data that identified one of them label, reader just from Gold sequence and RN_Nm, is replied out the ID_Nm of Q position, replys out whole identification number then;
4) in the working mechanism of reader, reader sends the ACK order one by one for all labels of having discerned, comprises the identification number of responding label in the order; The label that reader receives the ACK order that conforms to own identification number just is in state to be read;
5) reader sends the Read order, and this moment, all were in the label of state to be read, all adopted the Gold sequence that produces previously, and all data that oneself need to transmit are modulated and sent, and after sending, these labels are just got back to original state;
6) in the reader mechanism, carry out demodulate reception for data that label is sent out, according to number of tags of having discerned and last reception result unidentified Tag number is differentiated, for Unidentified label still, it is QueryReq that reader sends " inquiry again ", after label receives QueryReq, in label working mechanism, just produce a RN_Nm again, thereby select a new Gold sequence; Reader also can be in its mechanism, is the QueryAdjust order by " inquiry is adjusted ", and the Q parameter that forces all label utilizations to be transmitted is reselected new figure place Gold sequence generator; According to how much adjusting of remaining unidentified label data, the length of Gold sign indicating number is adjusted the code length of data transfer then and is adjusted overall time of identification, the original state of getting back to label working mechanism;
7) because Unidentified label uses new Gold sign indicating number that recognition data is modulated and sent, and wait for that the Ack of reader orders, like this, till reader can not receive new data, identifying finished, and reader is got back to original state;
8) in the reader, the Gold sign indicating number obtains after adding with all identical M sequence mould two of a pair of preferred cycle and speed; Adopt each one of them M sequencer initial value to carry out different being provided with and obtain different Gold sign indicating numbers Gold sign indicating number occurrence logic;
9) reader supposes that with sampling with 2 times Gold sequence transmission rate after the signal demodulation sampling resolution is 12, and sampled value is pressed into the sampled data storage queue of 2 * code length * 12; Simultaneously, receiving end has a local Gold sequencer, produces the Gold sequence that meets code length; When 2 sampled values of the every immigration of sampled data storage queue, the Gold sequencer will generate 2 successively
Q-1 Gold sequence to be differentiated, and expand to 2 times of code lengths respectively multiplies each other one to one with the sampled data storage queue separately and adds up, and has finished an elementary cell step of each sequence and signal correction computing; After sampled signal moves into two times of code lengths value, can obtain 2 altogether
Q-1 related operation result that length is code length is with 2
Q-1 Gold sequence is corresponding; In view of the above, reader is adjudicated and whether is had the pairing sign end of certain Gold sequence.
Beneficial effect:
Read when 1, realizing a plurality of RFID RFID tag (Tag), reduced time for reading, can realize reading fast of a large amount of RFID signs than traditional anticollision mechanism based on time-division processing.
2, have code division multiplexing mode signal to noise ratio (S/N ratio) height, strong interference immunity, good confidentiality, the advantage that the anti-multipath interference performance is strong.
3, can finally regulate recognition time according to the length of the number size adjustment modulation code of Tag, be fit to different application scenarios.
4, because the present invention has adopted the principle of ring shift to produce Goethe's sign indicating number sequence and carry out correlation computations, make the resource consumption of fetch equipment reduce, reduced the cost of fetch equipment.
5, adopt the chip technology of domestic and international main flow, make complexity and reduce.
Description of drawings
Fig. 1 is a Tag end working mechanism running status schematic flow sheet.
Fig. 2 is a reader end working mechanism running status schematic flow sheet.
Fig. 3 is a reader implementation structure functional schematic.
Specific implementation
Whole working mechanism sequential as shown in Figure 1.Working mechanism is divided into Tag and reader two parts.The present invention has adopted 22 of Q position initial value on Tag
QThe structure of-1 dust auxiliary sequence (M sequence) maker addition finally produces the Gold sequence of 2^Q-1 position.For simplified design, the present invention has adopted optional several Q value to comprise: 4,6,8,10,12.This Q value is selected with the parameter of command queries (Query) by reader.For for simplicity, the corresponding concrete Q value of the present invention, according to the initial value of one of them M sequence generator will finally produce 2
Q-1 Gold sequence permutation numbering.
1, Tag end duty mechanism
All receive the Tag of Query, carry out following action, as shown in Figure 2.
(1), in ID, exist the recurrence probability of some to be far longer than remaining position with the Tag of a collection of application because in the application of reality, the present invention in ID according to certain choosing method, choose Q bit, produce the integer of a Q bit (bit), be designated as (ID_Nm).In order to reach agile and all-purpose purpose, this choosing method can be revised with order Query by reader.As: from the most significant digit (MSB) of identification number (ID), choose Q high-order bit, perhaps the lowest order of ID (LSB) rises, and chooses Q low level bit.
In addition, the present invention makes each Tag produce one from 0 to 2^Q-1 (0,2^Q-1) the random integers side-play amount in the scope, be designated as RN_Nm, this random number and ID_Nm carry out mould 2^Q-1 addition, the result who produces finally produces the Gold sequence with this Tag as the initial value of first M sequence generator in the Gold sequence generator of this Tag.
(2) Tag uses this Gold sequence that own recognition data to be sent is modulated.This data content comprises: remove the remainder of the Q position of having taken out the front among the own ID, and the random integers side-play amount RN_Nm that uses previously.Certainly, before band spectrum modulation, at first also need to carry out Miller modulation (miller modulation), purpose is to make data become the bipolarity return-to-zero code, and this is beneficial to the detection of collision.These data are modulated and send to reader, wait for response (ACK) order of reader then.
(3) then, Tag response state to be identified such as transfers to from original state.
2, the duty mechanism of reader
The duty mechanism of reader also is the round-robin process:
(1) the reader signal of accepting the transmission of the Tag line correlation demodulation of going forward side by side, at this moment, if do not bump, promptly there is not plural Tag to produce same Gold sequence, though collision has perhaps taken place, reader is still differentiated the data that identified one of them Tag, and reader just can be from Gold sequence and RN_Nm, reply out the ID_Nm of Q position, reply out entire I D then.
(2) reader sends the ACK order one by one for all Tag that discerned, and comprises the ID that responds Tag in the order.The Tag that receives the ACK order that conforms to own ID just is in state to be read.
(3) Interrogator sends the Read order, and this moment, all were in the Tag of state to be read, all adopted the Gold sequence that produces previously, and all data that oneself need to transmit are modulated and sent, and after sending, these Tag just get back to original state.
(4) for still Unidentified Tag, Interrogator transmission QueryReq or QueryAdjust order.After Tag receives QueryReq, just produce a RN_Nm again, thereby select a new Gold sequence.Interrogator also can order by QueryAdjust, forces all Tag to utilize the Q parameter of being transmitted to reselect new figure place Gold sequence generator.The present invention can utilize this function, and according to how much adjusting of remaining unidentified Tag data, the length of Gold sign indicating number is adjusted the code length of data transfer then and adjusted overall time of identification.
Because Unidentified Tag uses new Gold sign indicating number that recognition data is modulated and sent, and wait for that the Ack of Interrogator orders.Get back to second step of system like this, again.Till Interrogator can not receive new data, identifying finished.
3, reader end receiver structure
Fetch equipment Interrogator end comprises emitting antenna and receiving antenna, amplification, down coversion demodulation, A/D sampling, displacement storage queue (length is determined by Gold sequence code length), Gold sign indicating number occurrence logic and displacement (related operation) logical block that adds up, as shown in Figure 2.
In the reader, the Gold sign indicating number obtains after adding with all identical M sequence mould two of a pair of preferred cycle and speed.The progression of M sequencer is identical.If two M sequence relative phase shift differences, resulting is different Gold sign indicating number sequences.To n level M sequence, total (2^n-1) individual out of phase, so can obtain (2^n-1) Gold sign indicating number sequence after adding by mould two, the cycle of these yards sequence is (2^n-1).Here, adopt each one of them M sequencer initial value to carry out different being provided with and obtain different Gold sign indicating numbers Gold sign indicating number occurrence logic.
Reader is sampled with 2 times Gold sequence transmission rate after the signal demodulation, and sampling resolution is 12bit, and sampled value is pressed into the sampled data storage queue of a 2 * code length * 12bit.Simultaneously, receiving end has a local Gold sequencer, produces the Gold sequence that meets code length.When 2 sampled values of the every immigration of sampled data storage queue, the Gold sequencer will generate N (to be differentiated) Gold sequence successively, and expand to 2 times of code lengths respectively, multiply each other one to one with the sampled data storage queue separately and add up, this has just finished an elementary cell step of each sequence and signal correction computing.When sampled signal moves into after two times of code lengths are worth, the related operation result that can to obtain N length altogether be code length, corresponding with N Gold sequence.
In view of the above, reader is adjudicated and whether is had the pairing sign end of certain Gold sequence.
Claims (1)
- A multiple access of realizing with cyclic shift mode insert, collision-proof method, it is characterized in that implementation method is:1) 22 of Q position initial value have been adopted on the label QThe structure of-1 M sequence generator addition finally produces 2 Q-1 Gold sequence; The span of Q comprises " 4,6,8,10,12 ", and this Q value is by the reader command queries ' parameter of Query ' selects;2) label according to the choosing method that begins from most significant digit or lowest order, is chosen Q position in identification number, produces the integer of a Q position, is named as ID_Nm; This choosing method can be revised with order Query by reader; Promptly from the most significant digit of identification number, choose a Q high position, perhaps the lowest order of identification number rises, and chooses Q low level, in addition, makes each label produce one " 0,2 Q-1 " the random integers side-play amount in the scope is named as RN_Nm, and this random number and ID_Nm carry out mould 2 Q-1 addition, the result of generation finally produces the Gold sequence with this label as the initial value of first M sequence generator in the Gold sequence generator of this label; Label uses this Gold sequence that own recognition data to be sent is modulated; This data content comprises: remove the remainder of the Q position of having taken out the front in the own identification number, and the random integers side-play amount RN_Nm that uses previously; Before band spectrum modulation, at first also need to carry out the Miller modulation, purpose is to make data become the bipolarity return-to-zero code of the detection of collision for the benefit of, these data are modulated and send to reader, wait for the response order of reader then, i.e. ACK;3) the reader signal of accepting the transmission of the label line correlation demodulation of going forward side by side, if do not bump, promptly there is not plural label to produce same Gold sequence, though collision has perhaps taken place, but reader is still differentiated the data that identified one of them label, reader just from Gold sequence and RN_Nm, is replied out the ID_Nm of Q position, replys out whole identification number then;4) in the working mechanism of reader, reader sends the ACK order one by one for all labels of having discerned, comprises the identification number of responding label in the order; The label that reader receives the ACK order that conforms to own identification number just is in state to be read;5) reader sends the Read order, and this moment, all were in the label of state to be read, all adopted the Gold sequence that produces previously, and all data that oneself need to transmit are modulated and sent, and after sending, these labels are just got back to original state;6) reader mechanism in, carry out demodulate reception for data that label is sent out, according to number of tags of having discerned and last reception result unidentified Tag number is differentiated, for Unidentified label still, it is QueryReq that reader sends " inquiry again ", after label receives QueryReq, in label working mechanism, just produce a RN_Nm again, thereby select a new Gold sequence; Reader also can be in its mechanism, is the QueryAdjust order by " inquiry is adjusted ", and the Q parameter that forces all label utilizations to be transmitted is reselected new figure place Gold sequence generator; According to how much adjusting of remaining unidentified label data, the length of Gold sign indicating number is adjusted the code length of data transfer then and is adjusted overall time of identification, the original state of getting back to label working mechanism;7) because Unidentified label uses new Gold sign indicating number that recognition data is modulated and sent, and wait for that the Ack of reader orders, like this, till reader can not receive new data, identifying finished, and reader is got back to original state;8) in the reader, the Gold sign indicating number obtains after adding with all identical M sequence mould two of a pair of preferred cycle and speed; Adopt each one of them M sequencer initial value to carry out different being provided with and obtain different Gold sign indicating numbers Gold sign indicating number occurrence logic;9) reader supposes that with sampling with 2 times Gold sequence transmission rate after the signal demodulation sampling resolution is 12, and sampled value is pressed into the sampled data storage queue of 2 * code length * 12; Simultaneously, receiving end has a local Gold sequencer, produces the Gold sequence that meets code length; When 2 sampled values of the every immigration of sampled data storage queue, the Gold sequencer will generate 2 successively Q-1 Gold sequence to be differentiated, and expand to 2 times of code lengths respectively multiplies each other one to one with the sampled data storage queue separately and adds up, and has finished an elementary cell step of each sequence and signal correction computing; After sampled signal moves into two times of code lengths value, can obtain 2 altogether Q-1 related operation result that length is code length is with 2 Q-1 Gold sequence is corresponding; In view of the above, reader is adjudicated and whether is had the pairing sign end of certain Gold sequence.
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101281587B (en) * | 2007-07-26 | 2010-06-09 | 北京航空航天大学 | Radio frequency recognition reading method and answering method |
| CN101430753B (en) * | 2007-11-08 | 2011-01-19 | 中兴通讯股份有限公司 | Label anti-collision method for radio frequency recognition system |
| CN102163989A (en) * | 2010-02-22 | 2011-08-24 | 刘礼白 | Method combining shift m-sequences spread spectrum and multilevel system code transmission |
| CN102254130A (en) * | 2010-05-21 | 2011-11-23 | 刘礼白 | Direct sequence spread spectrum-based radio frequency identification parallel response time domain dispersion method |
| CN101217807B (en) * | 2008-01-17 | 2011-12-07 | 中兴通讯股份有限公司 | Generation method of cyclic shift amount aggregation of random accessed channel of wireless communication system |
| CN101957907B (en) * | 2009-07-21 | 2013-02-27 | 刘礼白 | Radio frequency identification air interface adopting shift m-sequence family for spreading spectrum and parallel response |
| CN101958724B (en) * | 2009-07-21 | 2013-06-05 | 刘礼白 | Shift m sequence family spread spectrum RFID air interface reader-writer network |
| CN101957922B (en) * | 2009-07-21 | 2014-04-23 | 刘礼白 | Implementing method of air interface uplink channel for shift m sequence spread spectrum radio frequency identification device (RFID) |
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2006
- 2006-09-22 CN CNB200610096364XA patent/CN100524335C/en not_active Expired - Fee Related
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101281587B (en) * | 2007-07-26 | 2010-06-09 | 北京航空航天大学 | Radio frequency recognition reading method and answering method |
| CN101430753B (en) * | 2007-11-08 | 2011-01-19 | 中兴通讯股份有限公司 | Label anti-collision method for radio frequency recognition system |
| CN101217807B (en) * | 2008-01-17 | 2011-12-07 | 中兴通讯股份有限公司 | Generation method of cyclic shift amount aggregation of random accessed channel of wireless communication system |
| CN101957907B (en) * | 2009-07-21 | 2013-02-27 | 刘礼白 | Radio frequency identification air interface adopting shift m-sequence family for spreading spectrum and parallel response |
| CN101958724B (en) * | 2009-07-21 | 2013-06-05 | 刘礼白 | Shift m sequence family spread spectrum RFID air interface reader-writer network |
| CN101957922B (en) * | 2009-07-21 | 2014-04-23 | 刘礼白 | Implementing method of air interface uplink channel for shift m sequence spread spectrum radio frequency identification device (RFID) |
| CN102163989A (en) * | 2010-02-22 | 2011-08-24 | 刘礼白 | Method combining shift m-sequences spread spectrum and multilevel system code transmission |
| CN102163989B (en) * | 2010-02-22 | 2013-11-20 | 刘礼白 | Method combining shift m-sequences spread spectrum and multilevel system code transmission |
| CN102254130A (en) * | 2010-05-21 | 2011-11-23 | 刘礼白 | Direct sequence spread spectrum-based radio frequency identification parallel response time domain dispersion method |
| CN102254130B (en) * | 2010-05-21 | 2013-12-18 | 刘礼白 | Direct sequence spread spectrum-based radio frequency identification parallel response time domain dispersion method |
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| CN100524335C (en) | 2009-08-05 |
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