CN101145183A - Radio frequency identification multiple tag identification method - Google Patents

Abstract

The present invention discloses a multi-tag identifying method used for identifying radio frequency. After a reader is initialized and a tag is selected, the reader sends an access instruction of tag and the tag replies at a certain probability according to the information of the access instruction. If detecting multi-tag conflicts in prefixed time slot, the reader chooses to send retransmission instructions in a time slot or to receive the tag at the next time slot, wherein retransmission instructions lead the tag collided in the time slot to resend data frames. The information on parameters of the retransmission instructions at least comprises the information of replying of the tag and the confirmation information for the replying of the tag. And when the next time slot is chosen to receive the tag, the probability information of replying of the tag and confirmation information for replying of the tag in the access instructions need to be updated and access instructions of tag is sent out. The method of the present invention is capable of reducing tag collision, thereby increasing access efficiency of multi-tag, and reducing access time delay.

Description

A kind of many label identification methods that are used for radio-frequency (RF) identification

Technical field

The present invention relates to the REID of wireless communication field, relate in particular to the many label identification methods that are used for radio-frequency (RF) identification.

Background technology

In radio-frequency (RF) identification (RFID, Radio Frequency Identification) The Application of Technology, generally be the corresponding a plurality of electronic tags of a reader.When a plurality of labels insert reader simultaneously, will bump, thereby the information that can not correctly transmit in the label arrives reader.Therefore, need take certain mechanism to avoid collision or minimizing collision.

In order to insert label fast and effectively, in existing international standard ISO 18000-6, adopted the method for ALOHA and Binary Tree to solve the collision of label in inserting.Wherein, the essential characteristic of ALOHA is that the channel that label is replied by system is divided into some intervals (this is called time slot at interval) by the time, and requires label to select one of them time slot to reply.In operation, reader is given sending probability of each label (the perhaps scope of optional time slot) by instruction, and time slot of label selection is at random also replied on time; During if bump, then label is reselected time slot again and is sent or resend in each time slot subsequently, till all labels all insert reader.

In order to obtain higher access efficiency, the present invention is a ultimate principle with the ALOHA method, and has adopted a kind of method of leading random pulses collision detection therein, realizes better access efficiency with the subsidiary book invention.The method of this leading random pulses collision detection has been applied for patent before this.The ultimate principle of this method is: the pulse burst region that adds the certain hour width in the leader of the Frame that label sends.This pulse burst region is divided into the plurality of sub time interval once more, the label that desire sends one of picked at random in described plurality of sub time interval, and in selected sub-time interval, producing the burst of a high level, all the other times of pulse burst region are low level.When a time slot begins, all reply all synchronized transmission Frames of label, the reader end detects the burst in the Frame in the preset time window, and the number of record burst, thereby determines the number of collision labels in current this time slot according to the number of burst.

Summary of the invention

Technical matters to be solved by this invention is, a kind of many label identification methods that are used for radio-frequency (RF) identification are provided, and solves many tag recognition problem in the radio-frequency (RF) identification, realizes quick, the efficient access of many labels, reduces the label collision.

The invention provides a kind of many label identification methods that are used for radio-frequency (RF) identification, comprise the steps:

(1) the reader initialization finishes, and the label of effective on-site is selected;

(2) reader sends the label incoming instruction, begins to receive label, comprises the affirmation information that label is replied probabilistic information and label is replied in the wherein said label incoming instruction;

(3) label is replied with certain probability according to the information in the incoming instruction;

(4) reader receives the label return information and it is handled, if reader correctly receives the label return information, or receive when information is sky, change the reception of next time slot over to, the label that upgrades in the incoming instruction is replied probabilistic information and label answer confirmation and is sent the label incoming instruction, i.e. repeating step (2);

(5) if reader detects multi-label collision at predetermined time slot, being chosen in this time slot sends retransmission instructions or changes next time slot reception label over to, wherein, retransmission instructions makes the label that bumps in the current time slots resend Frame, at least comprise the affirmation information that label is replied probabilistic information and label is replied in the parameter information of described retransmission instructions, wherein, when selection changed next time slot reception label over to, label answer probabilistic information and the label answer confirmation upgraded in the incoming instruction also sent the label incoming instruction;

(6) after reader sends incoming instruction, when no longer including the label answer, finish access process.

Further, when reader changed next time slot reception label in described step (4) or the step (5), the step of upgrading the label answer probabilistic information in the incoming instruction comprised:

(a) in the label access procedure, establishing the initial value that number of tags is estimated is n ₀, be n in the estimated value of i time slot _i〉=0 and be integer, wherein, i 〉=0 and be integer is r in the number of i the detected answer label of time slot _i, its initial value r ₀=0, n then _I+1=n _i+ r _i, wherein, r _i=g _i+ e _i+ S _i, g wherein _iBe the number of tags of colliding in i the time slot, g _i〉=2 and be integer, e _iRepresent that whether replying number of tags in i the time slot is 0, if 0, e _iValue is-1, otherwise e _iValue is 0, s _iWhether represent has label successfully to insert in i the time slot, if success, s _iValue is-1, otherwise s _iValue is 0;

(b) label in the selection interval of i the selected answer timeslot number of time slot be [1, n _i], the answer probability of establishing i time slot is p _i, then $p_{i+1}=\frac{1}{n_{i+1}},$ Wherein, ${\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="A20061014101300161.png"\; state="\{\{state\}\}">p</figure-callout>}}_1=\frac{1}{n_0}.$

Further, when reader was chosen in this time slot transmission retransmission instructions in the described step (5), the step that multiple probabilistic information is signed back in the acceptance of the bid of renewal retransmission instructions comprised:

(A) establish n _j ⁱBe j sub-slots of i time slot, described time slot is the logic time slot, and j is nonnegative integer, wherein n ₀ ⁱ=c _i, c _iBe the collision labels number of i time slot, by the method acquisition of leading random pulses collision detection;

(B) establish r _j ⁱBe the number of detected answer label in the sub-slots that j again inserts in i the time slot, r ₀ ⁱInitial value is 0, then $n_{j+1}^i=n_j^i+r_j^i,$ Wherein $r_j^i=s_j^i,$ s _j ⁱRepresent whether successfully insert label in j sub-slots in i the time slot, if success, s _j ⁱValue is-1, otherwise value is 0;

(C) the selection interval that retransmits j the sub-slots selected answer timeslot number of label in i time slot be [1, n _j ⁱ], label is replied probability and is $p_{j+1}^i=\frac{1}{n_{j+1}^i},$ Wherein, $p_1^i=\frac{1}{c_i};$

(D) when selecting to retransmit instruction, the s that whether expression has label successfully to insert in i time slot _iValue, the number that is subjected to successfully to insert label in all sub-slots influences, $s_i=\underset{j}{\mathrm{\&Sigma;}}{s}_j^i.$

Further, when label is replied described in the step (3), in the Frame of replying, include a random pulses burst region, this label one of picked at random from this regional plurality of sub time interval, and producing the burst of a high level, all the other times in this zone are low level.

Further, reader described in the step (4) receives the label return information and it is carried out treatment step, be to come the test returns label information whether conflict is arranged by the method for leading random pulses collision detection, when carrying out collision detection, in certain parameter the number of recording impulse under the condition is set, represents this time slot to reply the number of label with pulse number.

Further, the described affirmation information that label is replied is when sending first or label takes place replying conflict, and this information be sky.

Further, step (1) comprising:

The reader initialization, finish the preliminary work with label communication;

Reader sends selection instruction at effective on-site, after label is received selection instruction, mates with alternative condition information in the selection instruction, and the label that satisfies alternative condition enters the label access procedure, and responsive tags inserts relevant instruction.

Use label identification method of the present invention, utilize the method for leading random pulses collision detection, answer is handled to label, can accurately know the label condition of answer, and can accurately upgrade the parameter in the incoming instruction, thereby can reduce collision according to return information, improve the access efficiency of many labels, reduce access delay.

Description of drawings

Fig. 1 is that the label that relates in the embodiment of the invention is replied the data frame structure synoptic diagram;

Fig. 2 is the label access process figure of the embodiment of the invention;

Fig. 3 is the label access procedure synoptic diagram of the embodiment of the invention.

Embodiment

Below in conjunction with drawings and the specific embodiments many label identification methods of the present invention are described in further detail.

As shown in Figure 1, shown the frame structure of the label answer data that relate in the label identification method of the present invention, be characterized in: in the leader of Frame, added the random pulses burst region.This zone is divided into the plurality of sub time interval once more, and the label that desire sends is from sub-time interval of picked at random wherein, and produces the burst of a high level, and all the other times of pulse burst region are low level.When a time slot began, all replied label synchronized transmission Frame, and the reader end detects burst in the preset time window, and the record number, thereby determined the number of collision labels in the current time slots.

As shown in Figure 2, the idiographic flow that has shown many label identification methods of the present invention.

Step 1, reader carries out initialization, finishes the preliminary work that communicates with label, shown in S1.

Step 2, reader is selected the label of effective on-site, shown in S2.Reader sends selection instruction, and after effectively the label of on-site was received selection instruction, the conditional information in the and instruction mated, and the label that satisfies alternative condition enters the label access procedure, and response inserts relevant instruction with label.

Step 3, reader sends the label incoming instruction, shown in S3, begins to receive label.The parameter information that comprises in the described label incoming instruction comprises at least: the affirmation information (send first and label takes place and reply when conflicting, this information is empty) that label is replied probabilistic information and label is replied.

Step 4, label are replied with certain probability, shown in S4 according to the information in the incoming instruction.

Step 5, reader receives the label return information and it is handled in preset time interval (or claiming time slot), shown in S5.Reader is meant to receiving information processing whether the test returns label information has conflict.Above-mentioned collision detection is that the method by leading random pulses collision detection realizes that the specific practice of carrying out collision detection is: in certain parameter the number of recording impulse under the condition is set, represents this time slot to reply the number of label with pulse number.

Step 6 if reader correctly receives the label return information at predetermined time slot, changes the reception of next time slot over to, shown in S6, S9.Wherein, need update instruction information (probabilistic information replied by label and label is replied confirmation) and send the label incoming instruction, promptly repeating step 3.

The renewal of multiple probabilistic information is signed back in step 6 acceptance of the bid, is according to reader the judged result of the label return information that receives to be adjusted.Specific practice is:

In the label access procedure, establishing the initial value that number of tags is estimated is n ₀, be n in the estimated value of i time slot _i(i 〉=0, and be integer; n _i〉=0, and be integer); Number at i the detected answer label of time slot is r _i, its initial value r ₀=0, then

n _i+1＝n _i+r _i (1)

Wherein,

r _i＝g _i+e _i+s _i (2)

In the formula (2), g _iBe the number of tags of colliding in i the time slot, g _i〉=2, and be integer; e _iRepresent that whether replying number of tags in i the time slot is 0, if 0, e _iValue is-1, otherwise e _iValue is 0; s _iWhether represent has label successfully to insert in i the time slot, if success, s _iValue is-1, otherwise s _iValue is 0.

Label in the selection interval of i the selected answer timeslot number of time slot be [1, n _i].If the answer probability of i time slot is p _i, then

$p_{i+1}=\frac{1}{n_{i+1}}---\left(3\right)$

Wherein, ${\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="A20061014101300161.png"\; state="\{\{state\}\}">p</figure-callout>}}_1=\frac{1}{n_0}.$

Step 7 when reader receives that information is sky, does not promptly have label and replys, and the label that changes next time slot over to inserts, shown in S6, S9, and repeating step 3.

Step 8 if reader detects multi-label collision at predetermined time slot, is chosen in this time slot retransmission instructions, i.e. S7, S8, S9 among Fig. 2, or change next time slot over to and receive label, i.e. S7, S9 among Fig. 2.

Retransmission instructions makes that collision labels resends in the current time slots, comprises the affirmation information that label replys probabilistic information, label is replied (send first in a time slot and when label taking place replying conflict, this information be sky) in its parameter information at least.

The method of retransmitting information updating in the instruction as in the step 6 to as described in the label incoming instruction information updating method.

If n _j ⁱBe j the sub-slots (time slot described here is the logic time slot, and j is a nonnegative integer) of i time slot, wherein $n_0^i=c_i,$ c _iBe the collision labels number of i time slot, by the method acquisition of leading random pulses collision detection; If r _j ⁱBe the number of detected answer label in the sub-slots that j again inserts in i the time slot, then r ₀ ⁱInitial value is 0, then

$n_{j+1}^i=n_j^i+r_j^i---\left(4\right)$

Wherein

$r_j^i=s_j^i---\left(5\right)$

In the formula (5), s _j ⁱRepresent whether successfully insert label in j sub-slots in i the time slot, if success, value is-1, otherwise is 0.

The selection interval that retransmits j the sub-slots selected answer timeslot number of label in i time slot be [1, n _j ⁱ].The answer probability is

$p_{j+1}^i=\frac{1}{n_{j+1}^i}---\left(6\right)$

Wherein, $p_1^i=\frac{1}{c_i}.$

When selecting to retransmit instruction, the number that successfully inserts label in this time slot in all sub-slots influences the s of this time slot _iFor

$s_i=\underset{j}{\mathrm{\&Sigma;}}{s}_j^i---\left(7\right)$

Further, in the step 8,, also can select to change over to next time slot and receive if when reader detects multi-label collision, update instruction information and send the label incoming instruction then, promptly repeating step 3.

Further specify many label identification methods of the present invention with instantiation below, as shown in Figure 3.

After supposing that reader is selected, there are 4 labels to participate in checking, but are unknown for the reader-tag number.Its process is as follows:

1, reader sends the label incoming instruction, begins to receive label.If the initial value n that the number of tags in the instruction is estimated ₀ Be 8, can get label by formula (3) and receive that the instruction back is with p ₁Be that 1/8 probability is replied.

2, the reader answer of receiving a label, i.e. s at first time slot ₁Be-1, e ₁Be 0, g ₁Be 0, label successfully inserts.Reader changes the reception of next time slot over to, promptly resends the label incoming instruction.By formula (1) and (2) as can be known, this moment number of tags estimated value n ₂Be 7, can get label by formula (3) and receive that the back is with p ₂Be that 1/7 probability is replied.

3, reader is received at second time slot and is sky, does not promptly have label and replys, and changes the reception of next time slot over to.Reader resends the label incoming instruction.At this moment, s ₂Be 0, e ₂Be-1, g ₂Be 0; Can get number of tags estimated value n by formula (1) and formula (2) ₃Be 6, can get label with p by formula (3) ₃Be that 1/6 probability is replied.

4, reader detects three labels and is replying, be i.e. s at the 3rd time slot ₃Be 0, e ₃Be 0, g ₃Be 3.Then by formula (1) and formula (2) can get number of tags estimated value n if being chosen in next time slot continues to receive this moment ₄Be updated to 9, by formula (3) can get label at the 4th time slot with p ₄Be 1/9 answer, the update method that subsequent timeslot provides according to the present invention and the like.

5, if reader is selected to continue to receive at the 3rd time slot, send and retransmit instruction.Then as can be known, the number of tags n that participates in this time slot by formula (4) and formula (5) ₁ ³Be 3; Instruct acceptance of the bid to sign back multiple Probability p as can be known by formula (6) ₁ ³Be 1/3.As shown in Figure 3:

A), 3 label As, B, C collision are arranged at the 1st sub-slots.

B) at the 2nd sub-slots, reader send to be retransmitted instruction, by formula (4), formula (5) and formula (6) label answer Probability p as can be known ₂ ³Still be 1/3.At this sub-slots, reader is received as sky, does not promptly have label and replys.

C) at the 3rd sub-slots, reader send to be retransmitted instruction, by formula (4), formula (5) and formula (6) label answer Probability p as can be known ₃ ³Still be 1/3.At this sub-slots, 2 label As, B collision are arranged.

D) at the 4th sub-slots, reader send to be retransmitted instruction, by formula (4), formula (5) and formula (6) label answer Probability p as can be known ₄ ³Still be 1/3.At this sub-slots, there is a label A to reply, and successfully receives, be i.e. s ₄ ³Be-1.

E) at the 5th sub-slots, reader send to be retransmitted instruction, by formula (4), formula (5) and formula (6) label answer Probability p as can be known ₅ ³Be updated to 1/2.At this sub-slots, two label Bs, C collision are arranged.

F) at the 6th sub-slots, reader send to be retransmitted instruction, by formula (4), formula (5) and formula (6) label answer Probability p as can be known ₆ ³Still be 1/2.At this sub-slots, reader is received as sky, does not promptly have label and replys.

G) at the 7th sub-slots, reader send to be retransmitted instruction, by formula (4), formula (5) and formula (6) label answer Probability p as can be known ₇ ³Still be 1/2.At this sub-slots, reader is received as sky, does not promptly have label and replys.

H) at the 8th sub-slots, reader sends retransmits instruction.By formula (4), formula (5) and formula (6) as can be known label reply Probability p ₈ ³Still be 1/2.At this sub-slots, there is a label B to reply, and successfully receives, be i.e. s ₈ ³Be-1.

I) at the 9th sub-slots, reader sends retransmits instruction.By formula (4), formula (5) and formula (6) as can be known label to reply probability be 1.At this sub-slots, there is a label C to reply, and successfully receives.

Continuation by 9 sub-slots inserts like this, has finished the access to 3 labels of collision, and its efficient is 1/3.For 4 overall labels, use 11 time slots to finish access altogether, its efficient is 4/11, near theoretical maximum 1/e.

Claims (7)

1. the many label identification methods that are used for radio-frequency (RF) identification is characterized in that, comprise the steps:

(1) the reader initialization finishes, and the label of effective on-site is selected;

(2) reader sends the label incoming instruction, begins to receive label, comprises the affirmation information that label is replied probabilistic information and label is replied in the wherein said label incoming instruction;

(3) label is replied with certain probability according to the information in the incoming instruction;

(4) reader receives the label return information and it is handled, if reader correctly receives the label return information, or receive when information is sky, change the reception of next time slot over to, the label that upgrades in the incoming instruction is replied probabilistic information and label answer confirmation and is sent the label incoming instruction, i.e. repeating step (2);

(5) if reader detects multi-label collision at predetermined time slot, being chosen in this time slot sends retransmission instructions or changes next time slot reception label over to, wherein, retransmission instructions makes the label that bumps in the current time slots resend Frame, at least comprise the affirmation information that label is replied probabilistic information and label is replied in the parameter information of described retransmission instructions, wherein, when selection changed next time slot reception label over to, label answer probabilistic information and the label answer confirmation upgraded in the incoming instruction also sent the label incoming instruction;

(6) after reader sends incoming instruction, when no longer including the label answer, finish access process.

2. the method for claim 1 is characterized in that, when reader changed next time slot reception label in described step (4) or the step (5), the step of upgrading the label answer probabilistic information in the incoming instruction comprised:

(a) in the label access procedure, establishing the initial value that number of tags is estimated is n ₀, be n in the estimated value of i time slot _i〉=0 and be integer, wherein, i 〉=0 and be integer is r in the number of i the detected answer label of time slot _i, its initial value r ₀=0, n then _I+1=n _i+ r _i, wherein, r _i=g _i+ e _i+ s _i, g wherein _iBe the number of tags of colliding in i the time slot, g _i〉=2 and be integer, e _iRepresent that whether replying number of tags in i the time slot is 0, if 0, e _iValue is-1, otherwise e _iValue is 0, s _iWhether represent has label successfully to insert in i the time slot, if success, s _iValue is-1, otherwise s _iValue is 0;

(b) label in the selection interval of i the selected answer timeslot number of time slot be [1, n _i], the answer probability of establishing i time slot is p _i, then $p_{i+1}=\frac{1}{n_{i+1}},$ Wherein, $p_1=\frac{1}{n_0}.$

3. the method for claim 1 is characterized in that, when reader was chosen in this time slot transmission retransmission instructions in the described step (5), the step that multiple probabilistic information is signed back in the acceptance of the bid of renewal retransmission instructions comprised:

(A) establish n _j ⁱBe j sub-slots of i time slot, described time slot is the logic time slot, and j is a nonnegative integer, wherein $n_0^i=c_i,$ c _iBe the collision labels number of i time slot, by the method acquisition of leading random pulses collision detection;

(B) establish r _j ⁱBe the number of detected answer label in the sub-slots that j again inserts in i the time slot, r ₀ ⁱInitial value is 0, then $n_{j+1}^i=n_j^i+r_j^i,$ Wherein $r_j^i=s_j^i,$ s _j ⁱRepresent whether successfully insert label in j sub-slots in i the time slot, if success, s _j ⁱValue is-1, otherwise value is 0;

(C) the selection interval that retransmits j the sub-slots selected answer timeslot number of label in i time slot be [1, n _j ⁱ], label is replied probability and is $p_{j+1}^i=\frac{1}{n_{j+1}^i},$ Wherein, $p_1^i=\frac{1}{c_i};$

(D) when selecting to retransmit instruction, the s that whether expression has label successfully to insert in i time slot _iValue, the number that is subjected to successfully to insert label in all sub-slots influences, $s_i=\underset{j}{\mathrm{\&Sigma;}}{s^i}_j.$

4. the method for claim 1, it is characterized in that, when label is replied described in the step (3), in the Frame of replying, include a random pulses burst region, this label one of picked at random from this regional plurality of sub time interval, and producing the burst of a high level, all the other times in this zone are low level.

5. the method for claim 1, it is characterized in that, reader described in the step (4) receives the label return information and it is carried out treatment step, be to come the test returns label information whether conflict is arranged by the method for leading random pulses collision detection, when carrying out collision detection, in certain parameter the number of recording impulse under the condition is set, represents this time slot to reply the number of label with pulse number.

6. the method for claim 1 is characterized in that, the described affirmation information that label is replied is when sending first or label takes place replying conflict, and this information be sky.

7. the method for claim 1 is characterized in that, step (1) comprising:

The reader initialization, finish the preliminary work with label communication;

Reader sends selection instruction at effective on-site, after label is received selection instruction, mates with alternative condition information in the selection instruction, and the label that satisfies alternative condition enters the label access procedure, and responsive tags inserts relevant instruction.

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