CN101989877B - Frame synchronization method in radio-frequency identification - Google Patents
Frame synchronization method in radio-frequency identification Download PDFInfo
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- CN101989877B CN101989877B CN 201010584959 CN201010584959A CN101989877B CN 101989877 B CN101989877 B CN 101989877B CN 201010584959 CN201010584959 CN 201010584959 CN 201010584959 A CN201010584959 A CN 201010584959A CN 101989877 B CN101989877 B CN 101989877B
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Abstract
The invention provides a frame synchronization method in a radio-frequency identification system, which comprises frame synchronization code design and a frame synchronization judgment mechanism. The method concretely comprises the following steps of: adopting binary sequence codes with good self relevance performance at an emitting end to be used as frame synchronization sub codes; then, sequentially connecting a plurality of frame synchronization sub codes for forming frame synchronization codes of the radio-frequency identification system; and judging the starting moment of information codes through forming a judgment sequence at a receiving end. The interference of the signal channel random noise is inhabited and the reliability of the frame synchronization results can be improved through the definite position relationship of a plurality of peak values of the invention based on the relevant calculation results.
Description
Technical field
The invention belongs to the radio-frequency (RF) identification communication technical field, be specifically related to a kind of frame synchronization method in radio-frequency identification.
Background technology
Radio-frequency (RF) identification (Radio Frequency Identification, RFID) system is a kind of contactless automatic recognition system.Radio-frequency recognition system comprises read write line and label.Read write line communicates by radiofrequency signal and label, and obtains the identifying information of storing on the label, and then label is carried out various operations.Read write line can be identified the label of high-speed motion, and can identify simultaneously a plurality of labels, and is swift and convenient to operate.
In radio-frequency (RF) identification communication, the communication information is transmitted with the form of frame signal.As shown in Figure 2, frame signal comprises frame swynchronization code 101 and information code 102, and wherein frame swynchronization code is in order to provide information code zero hour.Usually, the realization of frame synchronization comprises the design of transmitting terminal frame swynchronization code and receiving terminal frame synchronization decision mechanism.
At receiving terminal, frame synchronization mechanism is determined information code zero hour by the correlation that calculate to receive base band sequence and local frame swynchronization code.Therefore, estimate a good and bad autocorrelation performance that main criteria is frame swynchronization code of frame swynchronization code design.Autocorrelation performance usually use " peak value is with the ratio of main secondary lobe " expression, namely " Peak to Side Lobe Ratio " (P2SLR, unit are decibels, dB).But P2SLR is only relevant with auto-correlation computation result's amplitude.For example, among the radio-frequency (RF) identification standard ISO 18000-6B, read write line is 1100111010 to the frame swynchronization code of tag orientation, and its oscillogram as shown in Figure 3.The P2SLR of the frame swynchronization code among the ISO 18000-6B only is 5.23dB, as shown in Figure 4.Existing frame synchronization decision mechanism based on P2SLR is: at first set a threshold value; If current P2SLR is higher than this threshold value, just judge that current time is the zero hour of information code.Lower P2SLR and simple decision mechanism, so that the anti-interchannel noise jamming performance of traditional frame synchornization method is limited, frame synchronization result's confidence level and reliability are not high.
Summary of the invention
Main purpose of the present invention is, frame synchornization method in a kind of radio-frequency recognition system is provided, comprise frame swynchronization code design and frame synchronization decision mechanism, have to solve that the frame synchornization method performance is not good now, the discriminative information code confidence level zero hour and not high problem of reliability.
In order to achieve the above object, technical scheme of the present invention is the frame synchornization method in a kind of radio-frequency recognition system, it is characterized in that, comprises the steps:
Form the process of frame swynchronization code at transmitting terminal, comprise the steps:
Adopt the good binary sequence code of autocorrelation performance as the frame synchronization subcode, this frame synchronization subcode is designated as C
1, length is designated as L;
Based on C
1, obtain other n-1 frame synchronization subcode C
2, C
3..., C
n, C wherein
2, C
3..., C
nAnd C
1Polarity identical or opposite, i.e. C
2=+C
1Or C
2=-C
1, C
3=+C
1Or C
3=-C
1..., C
n=+C
1Or C
n=-C
1N is the integer greater than 1, can determine as required.
With n frame synchronization subcode C
1, C
2..., C
nBe linked in sequence successively, form the frame swynchronization code of radio-frequency recognition system.
At receiving terminal, synchronous according to following frame synchronization decision steps achieve frame:
The first step, initialization.
Make parameter p=0, p represents initial timer time,
Make P
Max0=0, P
Max0A frame synchronization judgment variables,
If the baseband signal sequence that receives is { y
1, y
2...;
Second step forms distinguishing sequence.
S distinguishing sequence of intercepting from the baseband signal sequence is designated as d successively
1, d
2..., d
s, the L+1 of s=(n-1) wherein, and:
d
1={y
1+p,?y
2+p,……,?y
L+p}，
d
2={y
2+p,?y
3+p,……,?y
L+1+p}，
……，
d
s={y
s+p,?y
s+1+p,……,?y
nL+p}；
The 3rd step, the zero hour of discriminant information code.
With each distinguishing sequence d
1, d
2..., d
sRespectively with frame synchronization subcode C
1Carry out related operation, obtain as a result sequence { P of related operation
1, P
2... P
s, make P
Max=Max (P
Max0, P
1..., P
s);
If (1-a) P
s＜P
S-kL＜(1+a) P
s(1-b) P
s＜P
Max＜(1+b) P
sSet up simultaneously, then the judgement moment (nL+p) is the zero hour of information code, and wherein a and b are less positive system parameterss; Otherwise, make p=p+1, P
Max0=P
MaxReturn second step.
Further, the frame synchronization subcode C in the technique scheme
1Can choose Barker code.
The invention has the beneficial effects as follows: based on the baseband signal sequence that receives and the higher P2SLR value of local frame synchronization subcode related operation result, guaranteed catching of the information code zero hour; Based on a plurality of peak values of related operation result allocation relation really, suppressed the interference of channel random noise, improved frame synchronization result's reliability, solved the not high defective of frame synchronization result reliability that traditional decision method causes; Because frame synchronization judging process of the present invention is identical with the length of related operation in the conventional frame synchronization decisions process, is L, therefore frame synchornization method of the present invention is identical with the computational complexity of conventional frame method for synchronous.
Description of drawings
Fig. 1 is the schematic flow sheet of frame synchornization method in the radio-frequency recognition system provided by the invention;
Fig. 2 is existing radio-frequency recognition system signal frame structure schematic diagram;
Fig. 3 is the oscillogram of the frame swynchronization code of frame structure in the existing protocol;
Fig. 4 is the related operation result of the frame swynchronization code of frame structure in the existing protocol;
Fig. 5 is the oscillogram (take n=2 as example) of the frame swynchronization code of the embodiment of the invention;
Fig. 6 is the related operation result (take n=2 as example) of the frame swynchronization code of the embodiment of the invention.
Embodiment
Below in conjunction with accompanying drawing a specific embodiment of the present invention is described in detail, but is not construed as limiting the invention.
The specific embodiment of the present invention, in the process of transmitting terminal formation frame swynchronization code, the flow chart with reference to shown in Figure 1 comprises the steps:
The frame synchronization subcode that the individual autocorrelation performance of n (n〉1) is good connects and is in turn connected into frame swynchronization code.Be without loss of generality, we are take n=2 as example.In the frame swynchronization code of this embodiment design, frame synchronization subcode C
1Adopting length is the Barker code 10110111000 of L=11, frame synchronization subcode C
2Adopt C
1The polarity opposite sequence, i.e. C
2=-C
1The frame swynchronization code that obtains at last is 10,110,111,000 01001000111, and its oscillogram as shown in Figure 5.
At receiving terminal, with reference to flow chart shown in Figure 1, synchronous according to following frame synchronization decision steps achieve frame:
The first step, initialization.
Make parameter p=0, p represents initial timer time,
Make P
Max0=0, P
Max0A frame synchronization judgment variables,
If the baseband signal sequence that receives is { y
1, y
2... }={ x
1x
2x
3x
4x
5x
6x
7x
8x
9x
10x
11x
1210,110,111,000 01001000111 x
35x
36x
37x
38x
39x
40x
41x
42x
43x
44x
45x
46, wherein x represents other binary data or the empty information of frame swynchronization code front and back;
Second step forms distinguishing sequence.
S distinguishing sequence of intercepting from the baseband signal sequence is designated as d successively
1, d
2..., d
s, the L+1=12 of s=(n-1) wherein, and:
d
1={y
1+p，y
2+p，……，y
L+p}={?x
1x
2x
3x
4x
5x
6x
7x
8x
9x
10?x
11}，
d
2={y
2+p，y
3+p，……，y
L+1+p}={x
2x
3x
4x
5x
6x
7x
8x
9x
10?x
11x
12}，
……，
d
s={y
s+p，y
s+1+p，……，y
nL+p}={?x
121011011100}；
The 3rd step, the zero hour of discriminant information code.
With each distinguishing sequence d
1, d
2..., d
sRespectively with frame synchronization subcode C
1Carry out related operation, obtain as a result sequence { P of related operation
1, P
2... P
s, make P
Max=Max (P
Max0, P
1..., P
s).
Then check (1-a) P
s＜P
S-kL＜(1+a) P
s(1-b) P
s＜P
Max＜(1+b) P
sWhether set up simultaneously, k=1 wherein ..., (n-1), a=0.2, b=0.2.If set up, judge that then (nL+p) is the zero hour of information code constantly; Otherwise, make p=p+1, P
Max0=P
MaxReturn second step.
When p=12, P
1, P
2..., P
sAs shown in Figure 6, P
Max=11.Empirical tests, (1-a) P
s＜P
S-kL＜(1+a) P
s(1-b) P
s＜P
Max＜(1+b) P
sSet up simultaneously.Therefore, adjudicate nL+p=34 and constantly be the zero hour of information code.Obviously, the 34th moment last bit of corresponding frame swynchronization code " 1 " begins related operation, the namely zero hour of information code.The frame synchronization judgement finishes.
In sum, the invention provides a kind of radio-frequency recognition system frame synchornization method, comprise and designed a kind of frame swynchronization code, set forth corresponding frame synchronization decision mechanism.Compare the frame swynchronization code of radio-frequency (RF) identification standard ISO 18000-B agreement, the P2SLR performance of the frame swynchronization code in this embodiment is increased to 10.41dB by 5.23dB; Frame synchronization decision mechanism among the present invention has improved frame synchronization result's confidence level and reliability simultaneously based on related operation result's amplitude information and positional information.
Claims (2)
1. the frame synchornization method in the radio-frequency recognition system is characterized in that, comprises the steps:
Form the process of frame swynchronization code at transmitting terminal, step is as follows:
Adopt the good binary sequence code of autocorrelation performance as the frame synchronization subcode, this frame synchronization subcode is designated as C
1, length is designated as L;
Based on C
1, obtain other n-1 frame synchronization subcode C
2, C
3..., C
n, C wherein
2, C
3..., C
nAnd C
1Polarity identical or opposite, i.e. C
2=+C
1Or C
2=-C
1, C
3=+C
1Or C
3=-C
1..., C
n=+C
1Or C
n=-C
1N is the integer greater than 1, can determine as required;
With n frame synchronization subcode C
1, C
2..., C
nBe linked in sequence successively, form the frame swynchronization code of radio-frequency recognition system;
At receiving terminal, synchronous according to following frame synchronization decision steps achieve frame:
The first step, initialization;
Make parameter p=0, p represents initial timer time,
Make P
Max0=0, P
Max0A frame synchronization judgment variables,
If the baseband signal sequence that receives for
Y1,
Y2...;
Second step forms distinguishing sequence;
S distinguishing sequence of intercepting from the baseband signal sequence is designated as d successively
1, d
2..., d
s, s=(n-1) L+1 wherein, and:
d
1={y
1+p,y
2+p,……,y
L+p}，
d
2={y
2+p,y
3+p,……,y
L+1+p}，
……，
d
s={y
s+p,y
s+1+p，……,y
nL+p}；
The 3rd step, the zero hour of discriminant information code;
With each distinguishing sequence d
1, d
2..., d
sRespectively with frame synchronization subcode C
1Carry out related operation, obtain as a result sequence { P of related operation
1, P
2... P
s, make P
Max=Max (P
Max0, P
1..., P
s);
If (1-a) P
s＜P
S-kL＜(1+a) P
s(1-b) P
s＜P
Max＜(1+b) P
sSet up simultaneously, then judgement constantly (nL+p) be the zero hour of information code, k=1 wherein ..., (n-1), a=0.2, b=0.2; Otherwise, make p=p+1, P
Max0=P
MaxReturn second step.
2. the frame synchornization method in the radio-frequency recognition system according to claim 1 is characterized in that, frame synchronization subcode C
1Choose Barker code.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6882633B2 (en) * | 1999-04-16 | 2005-04-19 | Infineon Technologies Ag | Method and device for synchronizing a mobile radio receiver with a frame structure of a radio signal |
| CN101425121A (en) * | 2007-11-01 | 2009-05-06 | 中兴通讯股份有限公司 | Information transmission system in radio frequency recognition system |
| CN101673195A (en) * | 2009-09-25 | 2010-03-17 | 中兴通讯股份有限公司 | Information transmission method, system and device in radio frequency identification |
-
2010
- 2010-12-13 CN CN 201010584959 patent/CN101989877B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6882633B2 (en) * | 1999-04-16 | 2005-04-19 | Infineon Technologies Ag | Method and device for synchronizing a mobile radio receiver with a frame structure of a radio signal |
| CN101425121A (en) * | 2007-11-01 | 2009-05-06 | 中兴通讯股份有限公司 | Information transmission system in radio frequency recognition system |
| CN101673195A (en) * | 2009-09-25 | 2010-03-17 | 中兴通讯股份有限公司 | Information transmission method, system and device in radio frequency identification |
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Address after: 300459, No. 399, Xiang Xiang Road, Tanggu hi tech Zone, Tianjin Binhai New Area Patentee after: Tianjin Institute of advanced technology Address before: 300459, No. 399, Xiang Xiang Road, Tanggu hi tech Zone, Tianjin Binhai New Area Patentee before: TIANJIN BINHAI CIVIL-MILITARY INTEGRATED INNOVATION INSTITUTE |
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Effective date of registration: 20200624 Address after: 300459, No. 399, Xiang Xiang Road, Tanggu hi tech Zone, Tianjin Binhai New Area Patentee after: TIANJIN BINHAI CIVIL-MILITARY INTEGRATED INNOVATION INSTITUTE Address before: 410073 Hunan province Changsha Kaifu District, Deya Road No. 109 Patentee before: NATIONAL University OF DEFENSE TECHNOLOGY |
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Effective date of registration: 20201026 Address after: 8-9 / F, building 9, Xin'an venture Plaza, 399 Huixiang Road, Tanggu marine science and Technology Park, Binhai New Area, Tianjin 300459 Patentee after: Tianjin Kunpeng Information Technology Co.,Ltd. Address before: 300459, No. 399, Xiang Xiang Road, Tanggu hi tech Zone, Tianjin Binhai New Area Patentee before: Tianjin Institute of advanced technology |