KR100726779B1 - Method of correcting recognition error for wireless recognition tag - Google Patents

Abstract

The present invention includes a step (a) and (b) as a method for correcting when a recognition error occurs in a reader for wireless recognition of a wireless identification tag. In the step (a), the pulses of the error occurrence region and the waveform of the pulse immediately after are detected. In the step (b), data of the error occurrence region and immediately after the pulse is set according to the characteristic of the detected waveform.

Description

Method of correcting recognition error for wireless recognition tag

1 is a diagram illustrating a conventional wireless identification tag system.

FIG. 2 is a block diagram illustrating an internal configuration of the reader of FIG. 1.

3 is a diagram illustrating a structure of data input to each of the second and third micro control devices of FIG. 2.

4 is a flowchart illustrating an algorithm for recognizing input data in each of the second and third micro control elements of FIG. 2.

FIG. 5 is a waveform diagram illustrating that impulse noise is inserted into signals input to each of the second and third micro control devices of FIG. 2.

FIG. 6 is a waveform diagram illustrating encoding characteristics of a signal transmitted from a radio recognition tag of FIG. 1 to a reader.

FIG. 7 is a state diagram illustrating an encoding characteristic of FIG. 6.

FIG. 8 is a waveform diagram illustrating an example of an error occurrence area that may be detected in each of the second and third micro control devices of FIG. 2.

9 is a waveform diagram showing pulses detected in one error occurrence region and pulses immediately after the same;

10 to 12 are waveform diagrams showing that data of the waveform of FIG. 9 is set by the correction method according to the present invention.

FIG. 13 is a flowchart illustrating an algorithm according to the present invention for correcting a recognition error when a recognition error occurs in the process of performing the recognition algorithm of FIG. 4.

FIG. 14 is a flowchart showing a detailed algorithm of the data setting step S1305 of FIG.

<Explanation of symbols for the main parts of the drawings>

11 ... wireless identification tags, 12, 201 ... antenna,

13 ... reader, 14 ... E.P.C network,

15 ... logistics network, 202 ... band pass filter,

203 ... balloon, 204 ... mixer,

205 ... filter, 206,210,211 ... micro control elements,

207 amplifiers, 208, 209 op amps,

N _I ... impulse noise,

6H ... high logic state with binary data '1',

6L ... low logic state with binary data '1',

3H ... high logic state making up binary data '0',

3L ... low logical state making up binary data '0',

81,91,101,111,121 ... Error occurrence area.

The present invention relates to a method for correcting a recognition error of a wireless identification tag. More particularly, the present invention relates to a method of correcting a recognition error in a reader for wireless recognition of a wireless identification tag.

Typical products are affixed with a radio recognition tag, for example a Radio Frequency IDentification (RFID) tag or a smart label (see International Publication WO 2002/37414), in the course of their manufacture. The radio recognition tag stores product information, and the stored product information is recognized by the reader of the radio identification tag.

Referring to FIG. 1, a conventional wireless identification tag system, for example, an RFID system, may include an RFID tag 11, an antenna 12, a reader 13, and an E.P. Product Code) network 14, and logistics network 15.

RFID tags 11 are classified into an active type with a battery and a passive type without a battery. Inside the passive RFID tag 11, a switching operation is performed using carrier energy supplied through the antenna 12 of the reader 13. Accordingly, the start signal commonly generated from the RFID tag 11 according to the switching operation includes a premise signal, a main signal, and a test signal (see FIG. 3).

The reader 13 processes the tag response signal input through the antenna 12 from the RFID tag 11 to obtain main data. The obtained main data is processed in the E.P.C network 14, and the result processed in the E.P.C network 14 is effectively used in the logistics network 15.

Referring to FIG. 2, the receiving circuit of the reader 13 of FIG. 1 includes a band pass filter 202, a balun 203, a mixer 204, a filter 205, a first micro control element 206, and an amplifier. 207, a first operational amplifier 208, a second operational amplifier 209, a second micro control element 210, and a third micro control element 211.

The tag response signal from the antenna 201 is filtered by the band pass filter 202 to the frequency of the set band.

The BALance to UNblance Transformer 203 adjusts the phase of the tag response signal to suit the reception frequency, thereby generating two signals having different phases.

The mixer 204 adds a 900-megahertz (MHz) carrier wave to the tag response signal of the I channel and the tag response signal of the Q channel, respectively, so that the tag response of the I channel including the base band is included. Generates the signal and the tag response signal of the Q channel.

The filter 205 operated by the first micro control element 206 filters the tag response signal of the I channel and the tag response signal of the Q channel to base frequency.

The tag response signal of the I channel and the tag response signal of the Q channel from the filter 205 are amplified by the amplifier 207.

The tag response signal of the I channel and the tag response signal of the Q channel from the amplifier 207 are converted into TTL (Transistor-to-Transistor Logic) level signals in each of the operational amplifiers 208 and 209. That is, analog signals are converted into digital signals.

Each of the second micro control element 210 and the third micro control element 211 receives the tag response signal of the I channel and the tag response signal of the Q channel from each of the operational amplifiers 208 and 209. To transmit. Accordingly, the first micro control element 206 sets an easy-to-read signal among the tag response signals of the I channel and the Q channel, and among the second micro control element 210 and the third micro control element 211. Either control element executes the algorithm described with reference to FIG.

3 illustrates data input to each of the second and third micro control elements 210 and 211 of FIG. 2 in order of preamble data, main data, and inspection data.

Here, the set width of each pulse is 12.5 micro-seconds (μs). As the inspection data, 16-bit cyclic redundancy check (CRC) data is used.

3 and 4, the main algorithm performed in each of the second micro control element 210 and the third micro control element 211 will be described.

First, when a signal from the RFID tag 11 is input (step S401), the input tag response signal is sampled (step S403).

Next, the sampled tag response signal is converted into binary data (step S405).

Next, in order to find the start position of the main data, preset reference premise data is used to compare and check premise data (step S407).

Next, if an error of the premise data check has occurred (step S409), an error signal is output (step S417).

On the other hand, if no error in the premise data check has occurred (step S409), the check data is used and the main data is checked (step S411).

Next, if a main data error occurs (step S413), an error signal is output (step S417), otherwise the main data is output (step S415). The output main data is displayed on the display panel provided in the reader (13 in FIG. 1) and transmitted to the E.P.C network (14 in FIG. 1).

According to the conventional wireless identification tag system as described above, when the response signal from the wireless identification tag is weak, noise and the surrounding environment are greatly affected. Accordingly, it is greatly influenced by the impulsive noise N _I as shown in FIG. 5. Accordingly, there is a problem that a recognition error occurs frequently in the reader.

It is an object of the present invention to provide a correction method that can reduce the number of recognition errors by correcting when a recognition error occurs in a reader of a wireless identification tag.

The present invention includes a step (a) and (b) as a method for correcting when a recognition error occurs in a reader for wireless recognition of a wireless identification tag.

In the step (a), the pulses of the error occurrence region and the waveform of the pulse immediately after are detected. In the step (b), data of the error occurrence region and immediately after the pulse is set according to the characteristic of the detected waveform.

According to the correction method of the present invention, data of the error occurrence region and immediately after the pulse is set according to the characteristics of the pulses of the error occurrence region and the waveform of the pulse immediately after that. Accordingly, even when a recognition error occurs in the reader of the wireless recognition tag, the recognition error may be corrected. This is because there is regularity of the waveform of the pulse according to the encoding scheme of the signal transmitted from the radio recognition tag to the reader.

Therefore, according to the correction method of the present invention, the number of recognition errors in the reader of the wireless identification tag can be reduced.

Hereinafter, preferred embodiments according to the present invention will be described in detail. Here, since the contents of FIGS. 1 to 4 are equally applied to the present embodiment, description thereof is omitted.

FIG. 6 is a waveform diagram illustrating encoding characteristics of a signal transmitted from the radio recognition tag 11 of FIG. 1 to the reader 13. FIG. 7 is a state diagram illustrating an encoding characteristic of FIG. 6. The encoding scheme having the characteristics of FIGS. 6 and 7 is the FM0 scheme of the International Organization for Standardization (ISO) 18000-6.

In FIG. 7, reference numeral 6H denotes a high logic state with binary data '1', 6L denotes a low logic state with binary data '1', 3H denotes a high logic state constituting binary data '0', and 3L indicates the low logic states that make up binary data '0' respectively.

6 and 7, for binary data '1', there is a single pulse of 25 micro-seconds (μs) with a high logic state 6H or a low logic state 6L.

For binary data '0', there are two pulses of 12.5 micro-seconds (μs) wide with a high logic state 3H and a low logic state 3L.

When switching from the waveform of binary data '1' of the high logic state 6H to the waveform of binary data '0', the pulse of the low logic state 3L exists in the first half of the waveform of the binary data '0'. In the latter half, there is a pulse of high logic state 3H.

When switching from the waveform of binary data '1' of the low logic state 6L to the waveform of binary data '0', the pulse of the high logic state 3H exists in the first half of the waveform of the binary data '0'. In the latter half, there is a pulse of low logic state 3L.

In switching from the waveform of binary data '0' to the waveform of binary data '1', a pulse of low logic state (3L) is present in the first half of the waveform of binary data '0' and a high logic state (3H) later. When a pulse of? Exists, a pulse of a low logic state 6L exists in the waveform of the binary data '1'.

In switching from the waveform of binary data '0' to the waveform of binary data '1', a pulse of high logic state (3H) is present in the first half of the waveform of binary data '0' and the low logic state (3L) later. In the case of the pulse of, the pulse of the high logic state 6H exists in the waveform of the binary data '1'.

Thus, since the regularity of the waveform according to the encoding scheme is present as described above, the data of the error generating region and the pulse immediately after it can be correctly set according to the characteristics of the pulses of the error generating region and the waveform of the pulse immediately after. Accordingly, even when a recognition error occurs in the reader (13 in FIG. 1) of the wireless recognition tag 11 in FIG. 1, the recognition error may be corrected.

FIG. 8 illustrates an example of an error occurrence area 81 that may be detected in each of the second and third micro control elements 210 and 211 of FIG. 2. Referring to FIG. 8, when a recognition error occurs due to an impulse noise N _I , each of the second and third micro control elements 210 and 211 sets an error occurrence area 81.

9 shows the pulses ①, ②, ③, and ④ detected in one error occurrence area 91 and the pulse ⑤ immediately after it.

Referring to FIG. 9, when the error generating area 91 is set, each of the second and third micro control elements 210 and 211 may have pulses ①, ②, ③, and ④ of the error generating area 91. The waveform of the pulse (5) is immediately detected. In addition, each of the second and third micro control elements 210 and 211 sets the data of the error generation region 91 and immediately after the pulse ⑤ according to the characteristic of the detected waveform.

10 to 12 show that the data of the waveform of FIG. 9 is set by the correction method according to the present invention. 9 to 12, a correction method according to the present invention when the FM0 encoding method of the International Organization for Standardization (ISO) 18000-6 is applied is as follows.

As shown in FIG. 10, the sum of the widths of the pulses (1, 2, 3, and 4 of FIG. 9) of the error generating region 101 is 50 microns, which is the sum of the widths of the two pulses of the binary data '1, 1'. If the width is equal to or longer than the seconds (μs), and the width of the pulse immediately after (5 in Fig. 9) is the same or shorter than 25 micro-seconds (μs), which is the width of one pulse of binary data '1', the error generating area 101 ) Binary data is set to '1, 1', and immediately after the binary data of the pulse (⑤) is set to '1'.

In addition, as shown in FIG. 11, the sum of the widths of the pulses (1, 2, 3, and 4 of FIG. 9) of the error generating region 111 is the sum of the widths of the two pulses of the binary data '1, 1'. If the width of the pulse (5 in Fig. 9) immediately after is shorter than 50 micro-seconds (μs) and equals to 25 micro-seconds (μs), which is the width of one pulse of binary data '1', the binary data of the error generating area 111 Is set to '0', and the binary data of the pulse (5) immediately after is set to '1'.

In addition, as shown in FIG. 12, the sum of the widths of the pulses (1, 2, 3, and 4 of FIG. 9) of the error occurrence region 121 is the sum of the widths of the two pulses of the binary data '1, 1'. Shorter than 50 micro-seconds (μs), and immediately after the width of the pulse (5 in Fig. 9) is shorter than 25 micro-seconds (μs), which is the width of one pulse of binary data '1', the error occurrence area 121 and immediately after The binary data of the pulse (5) is set to '1, 0'.

9 and 13, an algorithm according to the present invention for correcting a recognition error when a recognition error occurs in the process of performing the recognition algorithm of FIG. 4 will be described.

If an error signal is generated in the process of performing the recognition algorithm of FIG. 4 (step S1301), waveforms of pulses ①, ②, ③, and ④ of the error occurrence region 91 and immediately after that are detected. (Step S1303).

Next, the data of the error occurrence area 91 and immediately after the pulse? Is set in accordance with the detected waveform characteristic (step S1305). The detailed algorithm of this step S1305 will be described with reference to FIG.

Next, if a premise data error occurs in the process of performing the recognition algorithm of FIG. 4 (step S1307), the preset reference premise data is used to find the starting position of the main data, and the premise data is compared and checked. (Step S1309).

Next, when an error of the entire data check occurs (step S1311), the final error signal is output (step S1319).

On the other hand, if no error of the premise data check has occurred (step S1311), the check data is used and the main data is checked (step S1313).

Next, when a main data error occurs (step S1315), the final error signal is output (step S1319), otherwise the main data is output (step S1317). The output main data is displayed on the display panel provided in the reader (13 in FIG. 1) and transmitted to the E.P.C network (14 in FIG. 1).

FIG. 14 shows a detailed algorithm of the data setting step S1305 of FIG. 9 to 12 and 14, the detailed algorithm of the data setting step (S1305) of Figure 13 will be described.

50 micro-seconds (μs) where the sum of the widths of the fourth to fourth pulses (1, 2, 3, and 4 in FIG. 9) of the error generating region 101 is the sum of the widths of the two pulses of the binary data '1, 1'. Equal to or longer than () (step S1401), the width of the fifth pulse (5 in FIG. 9), which is a pulse immediately after the error occurrence region 101, is 25 micro-seconds (μs), which is the width of one pulse of binary data '1'. Is compared with (step S1403).

In step S1403, if the width of the fifth pulse (5 in Fig. 9), which is a pulse immediately after the error occurrence area (91 in Fig. 9), is equal to or shorter than 25 micro-seconds (μs), which is the width of one pulse of binary data '1', As shown in Fig. 10, the binary data of the error occurrence area 101 is set to '1, 1', and immediately after the binary data of the pulse? Is set to '1' (step S1405).

In step S1401, if the width of the fifth pulse (5 in Fig. 9), which is a pulse immediately after the error occurrence region (91 in Fig. 9), is longer than 25 micro-seconds (μs) which is the width of one pulse of binary data '1', the normal waveform Cannot be predicted, the process moves to step S1309 of FIG. 13 and outputs an error signal (step S1415).

 In step S1401, the sum of the widths of the first to fourth pulses (1, 2, 3, and 4 in FIG. 9) of the error occurrence region 101 is 50 micro- which is the sum of the widths of the two pulses of the binary data '1, 1'. If it is shorter than the second (μs), it is determined whether the width of the fifth pulse (5 in Fig. 9), which is a pulse immediately after the error occurrence area 101, is equal to 25 micro-seconds (μs), which is the width of one pulse of the binary data '1'. (Step S1407).

In step S1407, if the width of the fifth pulse ⑤ is equal to 25 micro-seconds (μs), which is the width of one pulse of binary data '1', as shown in Fig. 11, the binary data of the error generating region 111 is It is set to '0', and the binary data of the pulse 5 immediately after is set to '1' (step S1409).

If the width of the fifth pulse 5 is not equal to 25 micro-seconds (μs), which is the width of one pulse of binary data '1', in step S1407, the width of the fifth pulse 5 is one pulse of binary data '1'. It is determined whether the width is shorter than 25 micro-seconds (μs) (step S1411).

If the width of the fifth pulse ⑤ in step S1411 is shorter than 25 micro-seconds (μs), which is the width of one pulse of binary data '1', as shown in Fig. 12, the error occurrence area 121 and immediately after the pulse are shown. The binary data of (5) is set to '1, 0' (step S1413).

If the width of the fifth pulse ⑤ in step S1411 is not shorter than 25 micro-seconds (μs), which is the width of one pulse of binary data '1', the normal waveform cannot be predicted, and therefore, the flow goes to step S1309 of FIG. (Step S1417).

As described above, according to the method for correcting the recognition error of the wireless identification tag according to the present invention, the data of the error occurrence region and immediately after the pulse is set according to the characteristics of the pulses of the error occurrence region and the waveform of the pulse immediately after. do. Accordingly, even when a recognition error occurs in the reader of the wireless recognition tag, the recognition error may be corrected. This is because the regularity of the waveform of the pulse exists according to the encoding scheme of the signal transmitted from the radio recognition tag to the reader.

Therefore, according to the correction method of the present invention, the number of recognition errors in the reader of the wireless identification tag can be reduced.

The present invention is not limited to the above embodiments, but may be modified and improved by those skilled in the art within the spirit and scope of the invention as defined in the claims.

Claims (5)

In a method for correcting a recognition error occurs in the reader for wireless recognition of the wireless identification tag, (a) detecting the pulses in the error generating region and immediately after the waveform of the pulse, and and (b) setting data of the error occurrence region and immediately after the pulse according to the characteristic of the detected waveform. The method of claim 1, wherein in step (b), And the data of the error occurrence region and immediately after the pulse is set according to the sum of the widths of the pulses of the error occurrence region and the width of the immediately after pulse. The method of claim 2, The encoding scheme of the signal transmitted from the radio recognition tag to the reader is FM0 scheme of ISO (International Organization for Standardization) 18000-6, In step (b), The sum of the widths of the pulses of the error generating area is equal to or longer than the sum of the widths of the two pulses of binary data '1, 1', and the width of the pulse immediately after the same is equal to the width of one pulse of the binary data '1'. If short And the binary data of the error occurrence area is set to '1, 1' and the binary data of the pulse immediately after the set to '1'. The method of claim 3, wherein in step (b), If the sum of the widths of the pulses of the error generating area is shorter than the sum of the widths of the two pulses of binary data '1, 1', and the width of the pulse immediately after the same as the width of one pulse of the binary data '1', And the binary data of the error occurrence area is set to '0' and the binary data of the pulse immediately after the set to '1'. The method of claim 4, wherein in step (b), If the sum of the widths of the pulses of the error generating area is shorter than the sum of the widths of the two pulses of binary data '1, 1', and the width of the pulse immediately after the above is shorter than the width of one pulse of the binary data '1', And the binary data of the error occurrence region and immediately after the pulse is set to '1, 0'.

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