JP5371713B2 - Data processing apparatus, data processing method, and program - Google Patents

Description

  The present invention relates to a technique for reading data from a wireless tag such as an RFID (Radio Frequency IDentification) tag.

For example, an RFID reader / writer device described in Patent Document 1 (hereinafter referred to as a reader device) is intended to read data from all tags of a tag group in an inquiry process to the tag group.
As an inquiry process to a tag group, for example, there is InventoryTags.
InventoryTags is composed of a plurality of rounds.
The tags of the tag group basically respond only once with a single inventory tag.
Accordingly, when a tag that responds in one round is read by the reader device, it does not respond in the next round.
The round is divided into a plurality of time slots (hereinafter referred to as slots), and the tag randomly selects the slot and responds in the slot.
Therefore, a plurality of tags may respond to one slot. In this case, the responses of these tags cause a collision (co-region) and are not received by the reader device.
Therefore, the tag that failed to read responds in the next round.
Tags that fail to read in that round are read in the next round.
The reader device can read all the tags in the tag group by following the above procedure until no tags are left unread.

In Patent Document 1, it is assumed that the tags in the vicinity of the reader device have only a designated tag group, and that there is no tag that does not belong to the tag group and should not be read.
That is, in Patent Document 1, there is no tag that should not be read in the vicinity of the antenna of the reader device and should not be read, and it is assumed that all nearby tags are read.

JP-T 2009-518746

As described above, in Patent Document 1, it is assumed that there is only a designated tag group in the vicinity of the reader device, and there is no tag that does not belong to the tag group and should not be read.
However, in actual logistics and production line sites where RFID tags are applied, in addition to the items to be inspected (tag group), at that time, the items (tags) that do not need to be inspected, or items attached to the items are attached. Often there are no tags left.

In such a usage environment, people and things move and the reflected state of radio waves changes every moment due to the tag group reading work, and at a certain moment, a tag that should not be read is also a tag group that should be read. Sometimes it is read from the reader together.
This phenomenon is called “misread”, and a tag read incorrectly is called “misread tag”. When this phenomenon occurs, for example, a distribution management system that operates based on tag information from a reader malfunctions as if an article that has not been shipped from the distribution center has been shipped.

  The present invention has been made in view of the above problems, and has as its main object to avoid misreading when reading a large number of wireless tags.

The data processing apparatus according to the present invention
The wireless tag is connected to an antenna that receives a wireless signal including the wireless tag ID (Identification).
Each time the antenna receives a radio signal, a received signal strength measuring unit that measures the received signal strength at the time of radio signal reception;
An ID detection unit for detecting an ID of the wireless tag from a reception signal of the antenna;
An ID strength association unit that associates the ID detected by the ID detection unit with the received signal strength measured by the received signal strength measuring unit;
The received signal strength level measured by the received signal strength measuring unit is analyzed, and the ID detected by the ID detecting unit is not a target of ID reception, but an ID is received by mistake. And a misread ID discriminating unit for discriminating misread IDs from the stored wireless tags.

  According to the present invention, even if a radio signal from a tag that is not a reception target is received and the ID of the tag that is not a reception target is detected, the ID of the tag that is not a reception target is misread by analyzing the received signal strength. Therefore, it is possible to avoid a malfunction caused by a misread ID.

1 is a diagram illustrating a configuration example of an RFID system according to Embodiment 1. FIG. FIG. 3 illustrates a configuration example of a reader device according to the first embodiment. The figure which shows the example of arrangement | positioning of the antenna which concerns on Embodiment 1, a tag group, a non-target tag. FIG. 3 is a flowchart showing an operation example of the reader device according to the first embodiment. FIG. 6 is a diagram showing an example of a misread tag discrimination criterion according to the first embodiment. The figure which shows the example of arrangement | positioning of the antenna which concerns on Embodiment 2, a tag group, a non-target tag. FIG. 9 is a flowchart showing an operation example of the reader device according to the second embodiment. FIG. 9 is a flowchart showing an operation example of the reader device according to the second embodiment. FIG. 6 illustrates a configuration example of an RFID system according to Embodiment 3; The figure which shows the example of arrangement | positioning of the antenna, tag group, non-target tag, etc. which concern on Embodiment 3. FIG. 10 is a flowchart showing an operation example of the reader device according to the third embodiment. FIG. 10 is a flowchart showing an operation example of the reader device according to the third embodiment. The flowchart figure which shows the operation example of the reader apparatus which concerns on Embodiment 1-3. The figure which shows an example of the hardware resource of the reader apparatus shown in Embodiment 1-3.

The method of realization differs depending on whether the tag group stops in front of the antenna of the reader device and inspects, or inspects while moving in front of the antenna.
Further, the implementation method differs depending on whether the number of antennas connected to the reader device is one or not.
Therefore, in the first embodiment, the case where the tag group is stopped in front of the antenna of the reader device will be described, and in the second and third embodiments, the case where the tag group is moved in front of the antenna of the reader device will be described.
In the first and second embodiments, a case where the antenna connected to the reader device is one case, and in the third embodiment, a case where a plurality of antennas are used will be described.

Embodiment 1 FIG.
An embodiment in the case where the number of antennas is 1 and the tag group is stopped will be described with reference to FIGS.

FIG. 1 is a configuration diagram showing the entire RFID system according to the present embodiment.
In FIG. 1, a host computer 1 issues a tag read command to an RFID reader device 2 (hereinafter also referred to as a reader device 2).
The network 3 connects the host computer 1 and the reader device 2.
The antenna 4 is connected to the reader device 2 by an antenna cable 5.
The antenna 4 and the tag group 6 communicate with each other by radio waves (the reader device sends commands all at once, and each tag returns a response).
The reader device 2 includes a network interface unit 21, a communication control unit 22, a wireless communication unit 23, and a sensor 28.

The tag group 6 is a group of wireless tags (hereinafter simply referred to as tags) such as RFID tags affixed to a baggage on a carriage 7.
The tags are 601a, 601b, 601c, 602a, 602b,. . . . , 610a, 610b, 610c and 10 rows × 3 columns = 30.
It is assumed that the tag group 6 is placed on the carriage 7 and stops in front of the antenna 4.
When it is detected by the sensor 28 that the carriage 7 has come to the specified position, the tag reading process is started.
In the above environment, the non-target tag 8 is left a little away from the antenna 4.
The non-target tag 8 is a tag that is not a target for reading tag data by the reader device 2. If the tag data of the non-target tag 8 is erroneously read, it becomes a misread tag. As described above, the misread tag causes a malfunction.

  FIG. 2 is a diagram illustrating the communication control unit 22 and the wireless communication unit 23 in more detail.

In the figure, the communication control unit 22 includes a command analysis unit 221, a command generation unit 222, a round control unit 223, a memory 224, a response generation unit 225, and a determination reference value storage unit 226.
The wireless communication unit 23 includes a transmission signal conversion unit 231, a circulator 232, a reception filter 233, a HandleNumber detection unit 234, a co-region detection unit 235, an ID detection unit 236, and an RSSI measurement unit 237.
RSSI is the received signal strength (Receive Signal Strength Indicator).
In addition, a command signal, a HandleNumber signal, a co-region detection signal, an ID signal, and an RSSI signal are connected between these blocks.

  Among the configurations shown in FIG. 2, the main components will be described below.

  The ID detection unit 236 acquires a reception signal from the tag received by the antenna 4 via the circulator 232 and the reception filter 233, and extracts an ID (IDentification) of the tag from the reception signal.

  The RSSI measurement unit 237 measures the received signal strength (RSSI) at the time of receiving the radio signal every time the antenna 4 receives the radio signal. The ID detection unit 236 is an example of a received signal strength measurement unit.

  The memory 224 receives the tag ID information from the ID detection unit 236, receives the RSSI value from the RSSI measurement unit 237, and stores the tag ID and the RSSI value in association with each other. The memory 224 is an example of an ID strength association unit.

The round control unit 223 analyzes the RSSI level measured by the RSSI measurement unit 237, and the ID received from the ID detected by the ID detection unit 236 is erroneously received. The misread ID from the tag that has been done (non-target tag 8) is determined.
The round control unit 223 is an example of a misread ID determination unit.

The determination reference value storage unit 226 stores a determination reference value for determining the misread ID by the round control unit 223.
The determination reference value storage unit 226 stores, for example, a threshold value for distinguishing the received signal strength of the radio signal from the tag group 6 that is the target of ID reception from the received signal strength of the non-target tag 8.
Further, for example, the determination reference value storage unit 226 stores the number of tags included in the tag group 6 that is an ID reception target as the ID reception target number.
The determination reference value storage unit 226 is an example of a threshold storage unit and an ID reception target number storage unit.

  FIG. 3 is a diagram illustrating a physical arrangement relationship of the antenna 4, the tag group 6, the cart 7, and the non-target tag 8 in FIG. 1.

In FIG. 3, articles with tags attached are loaded on a carriage 7 in a state of 3 rows (a row to c row) at a height of 10 stages.
A row a is arranged in front of the carriage 7, b row in the middle, and c row in the rear.
For example, row a is stacked with 601a, 602a, and 603a from the top, and 610a is stacked at the bottom.
The tag group 6 pinched by the carriage 7 moves together and stops in front of the antenna 4.
Further, the non-target tag 8 is placed at the limit of whether or not communication is possible from the viewpoint of the directivity and distance of the antenna 4.
The non-target tag 8 is not placed in a place where it can always stably communicate with the antenna 4 (close to the antenna, in front of the antenna, etc.).
This is because in such a case, an operator of the system can easily notice an abnormality and move the non-target tag 8 to a place farther away from the antenna 4 (a place where communication is impossible).
Basically, tags that are close to each antenna are easy to read, but due to the influence of radio wave reflection and fading, far tags may be read or nearby tags may not be read. .

  Next, with reference to FIG. 13, the operation until the host computer 1 receives the tag ID in FIG. 1 will be described.

First, the host computer 1 transmits an ID read command to the RFID reader device 2 via the network 3.
The RFID reader device 2 interprets the signal transmitted by the network interface unit 21 through the ID reading command, and the ID reading command is transmitted to the communication control unit 22.
2 analyzes the ID reading command from the host computer, creates a communication command sequence for reading the ID at the command generation unit 222, and the sensor 28 has the tag group 6 present. Is detected, the wireless communication unit 23 is informed. The command sequence is composed of one command (Select command) for select processing and a command sequence (Query, Query Repeat, Ack, etc.) for round processing.
Receiving the command string, the wireless communication unit 23 converts the communication command into a signal to be transmitted wirelessly by the transmission signal conversion unit 231 in FIG. This signal is output from the reader device 2 via the circulator 232 and sent to the antenna 4 via the antenna cable 5.
The above is the initial processing (S1301) of FIG.

When the communication command sent from the antenna 4 reaches the tag group 6, the tag group 6 returns a response, and the response (radio signal including the ID) is received by the antenna 4, and is transmitted to the wireless communication unit 23 via the cable 5. It returns (S1302).
In the wireless communication unit 23 of FIG. 2, the response from the tag is input to the reception filter 233 via the circulator 232.
The circulator 232 is a device that defines the signal propagation direction, and the signal from the transmission signal converter 231 is output to the antenna cable 5 and does not go to the reception filter 233. The input signal from the antenna cable 5 has a function that goes to the reception filter 233 and does not go to the transmission signal conversion unit 231.
In the reception filter 233, signal components unrelated to the response signal from the tag are significantly attenuated, and the response signal from the tag can be remarkably observed at the output of the reception filter 233.
From this signal, the HandleNumber detection unit 234 detects the HandleNumber, the coregion detection unit 235 detects the tag response wave co-region (collision), and the ID detection unit 236 detects the tag ID (S1304) (ID detection). Step), the RSSI measuring unit 237 measures the power (RSSI) of the signal component when the ID is detected (S1303) (received signal strength measuring step).
Information on these tags (HandleNumber, co-region detection, ID, RSSI) is sent to the communication control unit 22.

During the round process, the communication control unit 22 reads all the tag IDs (typically, InventoryTags) based on the tag information (HandleNumber, co-region detection, ID, RSSI) read from the wireless communication unit 23. (Process) is recommended.
The round control unit 223 is the center of the total tag ID reading process.
The ID and RSSI are stored in the memory 224, and the ID and RSSI are stored in association with each other (S1305) (ID strength association step).
The ID and RSSI of the memory 224 are read when the round control unit 223 is necessary.
The response generation unit 225 generates a list of IDs to be returned to the host computer while proceeding with the process of reading all tag IDs.

When all the tags of the tag group 6 have been read, all the IDs are stored in the communication control unit 22. Here, the round control unit 223 analyzes the RSSI level of each tag and misreads the tags. The misread ID which is the ID is determined (S1306) (misread ID determining step).
And what detected and removed misread ID is regular ID.
These regular ID numbers are converted into signals that propagate through the network by the network interface unit 21 and are transmitted to the host computer 1 via the network 3.

Next, the flow of the processing for reading all tag IDs once will be described with reference to FIG.
Here, the InventoryTags process will be described as an example.
The InventoryTags process uses a command between a reader device and a tag group called C1G2 (Class1 Generation 2) defined by EPC (Electronic Product Code) Global.

First, in S20, the round control unit 223 initializes the total number of tags T = 0 read in the entire InventoryTags process.
Next, in S21, the reader device 2 transmits a Select command from the circulator 232 to the tag group 6 under the control of the command generation unit 222 and the transmission signal conversion unit 231, and the tag group is irrelevant to the current process. If there is a tag, remove it. Specifically, tags other than the tag attached to the article are excluded.
The non-target tag 8 is not an exclusion target.
The tag to be read this time is initialized by the Select command, and has not yet been read from the reader device 2.
Next, in S22, the round control unit 223 initializes the slot number K = 1, the tag number R = 0 read in the round, and the co-region number C = 0.
In S23, under the control of the command generation unit 222 and the transmission signal conversion unit 231, in the reader device 2, the circulator 232 transmits a Query command, and designates the number of slots by the Query command.
The tag returns a response in any one of these slots. The slot number is determined by a random number.
Next, in the reader device 2, in S24, the HandleNumber detection unit 234 determines whether there is a response (HandleNumber) from the tag. If there is, the process proceeds to S25, and if not, the co-region detection unit 235 confirms the presence or absence of the co-region detection. .

In S25, in the reader device 2, the circulator 232 transmits an Ack command under the control of the command generation unit 222 and the transmission signal conversion unit 231, and the tag responds to the ID.
Next, in S <b> 26, in the reader device 2, the ID detection unit 236 detects the ID from the tag, and the RSSI measurement unit 237 measures the received signal strength (RSSI: Receive Signal Strength Indicator).
Then, the set of ID and RSSI is stored in the memory 224 in the reader device.
Further, the round control unit 223 counts up the total number T of tags read.
Further, the round control unit 223 counts up the number R of read tags in S27.

In S30, to enter the next slot, the circulator 232 transmits a Query Repeat command under the control of the command generator 222 and the transmission signal converter 231.
A tag that has received a Query Repeat command after Ack recognizes that the ID has been read from the reader device 2. In other words, in the subsequent round processing, this tag does not return a response.
If the round control unit 223 does not reach the number Kend of slots to be executed in this round in S31, the round control unit 223 increments (S32) and repeats the processes of S24 to S31.
In S33, if both the current tag number R and co-region number C are zero, the process proceeds to S35. Otherwise, the process returns to S22.
In S35, the round control part 223 selects what is determined to be a misread ID from the set of T sets of IDs and RSSIs accumulated in the memory by the above processing.
As shown in FIG. 5, the selection method differs depending on whether the number of tags in the tag group 6 is known in advance or not.

As shown in FIG. 5, (1) when the tag number of the tag group 6 is known in advance, the tag number of the tag group 6 is set to Tknown. This Tknown is the number of ID reception targets. Further, Tknown is stored in the determination reference value storage unit 226.
If the tag is not overwritten, the relationship T ≧ Tknown is established. In the embodiment, it is assumed that the performance of the reader device 2 is sufficiently good and no overwriting occurs.
When T = Tknown, the round control unit 223 determines that there is no “misread tag”, and considers all IDs on the memory as IDs of the tag group 6.
On the other hand, when T> Tknown, the round control unit 223 determines that ΔT = (T−Tknown) “misread IDs” exist. The tags of the tag group 6 are stationary before the antenna 4, so that a sufficiently good communication environment is ensured and a high RSSI value is obtained. On the other hand, the misread tag has a worse communication environment and a lower RSSI value than the tag included in the tag group 6. Therefore, the set of (ID, RSSI) is sorted by RSSI value, and it is determined that ΔT IDs are “misread IDs” from the lowest RSSI value.

As shown in FIG. 5, (2) when the tag number of the tag group 6 is not known in advance, the minimum RSSI value of the tag group 6 is determined in advance. Let that value be RSSIth. This RSSIth is stored in the determination reference value storage unit 226. In addition, RSSIth must be selected so that the relationship of “RSSI of regular tag” ≧ RSSIth> “RSSI of misread tag” is satisfied.
Under this condition, the round control unit 223 considers a pair of (ID, RSSI) whose RSSI value is smaller than RSSIth as “misread ID”. The ID set obtained by removing the misread IDs from the T IDs read is the set of IDs obtained by InventoryTags.

  The above is the processing of InvenoraryTags when the tag group 6 is stopped.

Thus, in this embodiment, even if a tag that is not a reception target exists near the antenna of the reader device, and the reader device reads an ID from a tag that is not a reception target, the tag that is not a reception target Can be eliminated as misread IDs, so that it is possible to avoid malfunctions caused by reading misread IDs.
Moreover, in this Embodiment, misread ID can be discriminate | determined and misread ID can be excluded in any of the case where the number of tags of a tag group is known, and when it is not known.

In the present embodiment, an RFID reader / writer device including the following means has been described.
(A) Means for executing a tag ID total number reading process (InventoryTags).
(B) Means for measuring the received signal strength (RSSI) simultaneously with reading the tag ID.
(C) Means for recording the received signal intensity read for each tag ID.
(D) Means for determining a tag that should not be read (referred to as a misread tag) by recording the received power of the ID.

In this embodiment, an RFID reader / writer device including the following means.
(A) Means for setting a threshold for separating the received signal strengths of misread tags and regular tags.
(B) Means for determining an ID having a received signal strength smaller than a threshold value as a misread tag.

In this embodiment, an RFID reader / writer device including the following means.
(A) Means for setting the total number of tags to be read.
(B) Means for sorting IDs in order of received signal strength.
(C) Means for determining an ID having a lower received signal strength as a misread tag from the total number of tags to be read.

Embodiment 2. FIG.
In the present embodiment, an example in which the tag group 6 is inspected while moving will be described with reference to FIGS.

  The overall configuration of the RFID system is the same as that of Embodiment 1, and is shown in FIG.

The physical arrangement relationship at the time of reading the tag group 6 is shown in FIG. When the cart 7 and the tag group 6 pass in front of the antenna 4 without stopping, the tag group 6 is read by the reader device 2.
In this case, the InvenoraryTags process generally begins before coming to the front of the carriage and continues until the carriage passes.
That is, the position of the sensor 28 is generally in front of the traveling direction of the carriage.
If the tag is barely communicable due to the distance from the antenna and the directivity, it may happen to be able to communicate.
In such a case, if the method of the first embodiment is applied as it is, the RSSI of the tag becomes a low value, and it may be determined as a misread tag.
Therefore, in the present embodiment, the operation of the reader device 2 is changed as shown in FIG.
The only difference from FIG. 4 of the first embodiment is that step S34 is present.
S34 is a step of re-execution of the ID reading sequence for the ID having a low RSSI at the end of the round. A specific flow of this step is shown in FIG.

In FIG. 8, the number of the set of T (ID, RSSI) is U.
U-th ID is described as ID (U), RSSI is expressed as RSSI (U), and U takes an integer value from 0 to T-1.
An RSSI threshold that can be distinguished from misread tags is determined in advance as RSSIth. This RSSIth is stored in the determination reference value storage unit 226.

In S40, the round control unit 223 initializes the number of tags U = 0 read in the InventoryTags processing so far.
Next, in S41, the round control unit 223 checks whether or not the RSSI of the Uth tag is lower than RSSIth. If it is lower, the roundth control unit 223 sets the Uth tag as a reread target (re-assigns the Uth tag ID). As a reception target ID), the process proceeds to step S42. If the RSSI of the U-th tag is not lower than RSSIth, this tag does not need to be read again, and the process proceeds to step S48.
In S42, under the control of the command generation unit 222 and the transmission signal conversion unit 231, the circulator 232 transmits a Select command to the tag group 6 so as to respond only to the tag having the ID of the Uth tag. Such processing can be performed by using an EPC Global command.
In S43, the circulator 232 transmits the Query command under the control of the command generation unit 222 and the transmission signal conversion unit 231. Here, 1 is designated as the number of slots. Therefore, if communication is possible by radio waves, only the tag with ID [U] always responds.
Next, in S44, the HandleNumber detection unit 234 determines whether there is a response (HandleNumber) from the tag. If there is a response, the process proceeds to step S45.
On the other hand, if this tag is not in a communicable position, there is no response. In that case, the process proceeds to step S48.

In S45, the circulator 232 transmits an Ack command under the control of the command generation unit 222 and the transmission signal conversion unit 231, and the tag responds with an ID thereto.
In S46, the ID detection unit 236 extracts the ID from the tag, and the RSSI measurement unit 237 measures the RSSI.
Further, the RSSI measurement unit 237 determines whether the RSSI measured in S46 is higher than the RSSI [U] already stored in the memory 224. If it is higher, the process proceeds to step S47. Otherwise, the process proceeds to step S48.
In S47, the RSSI measurement unit 237 replaces RSSI [U] with the RSSI received this time.
Next, in S48, the round control unit 223 increments U to check the next tag recorded in the memory 224.
In S49, if U is smaller than the tag number T read so far, the process returns to S41, and the processes of S41 to S48 are repeated. If U = T, the process is terminated.

In FIG. 7, the process of step S <b> 34 described above gives a chance to rewrite the RSSI again for a tag having a low RSSI.
In other words, in the tag of tag group 6, tags that can be read at a position far from the antenna also measure RSSI again when it comes to a position close to the antenna. Therefore, when inspection is completed, the RSSI is rewritten to a sufficiently high RSSI. Has been.
Since the RSSI value is improved in the process of step S35, the method according to FIG. 5 can be used as it is.
In this embodiment, when the number of tags is known in advance, RSSIth may be set to a larger value instead of a strict value.
This is because if the RSSI value of the misread tag is relatively lower than the regular tag, the correct tag will not be mistaken as the misread tag even if the RSSIth is high.
In the case where the number of tags is not known in advance, the RSSIth must be selected so that the relationship of “RSSI of regular tag” ≧ RSSIth> “RSSI of misread tag” is satisfied.

Thus, according to the present embodiment, when an ID is read from a moving tag group, even if there is a tag (ID) whose RSSI value is lower than the threshold value, the tag having a low RSSI value is read again. Since the ID reading process is performed, since an RSSI value higher than the threshold value can be obtained by movement if the tag is a regular tag, it is possible to eliminate a misread tag (misread ID) with high accuracy.
Also in the present embodiment, it is possible to determine the misread ID and eliminate the misread ID in both cases where the number of tags of the tag group is known or not known by rereading.

In the present embodiment, an RFID reader / writer device including the following means has been described.
(A) Means for setting a threshold value of received signal strength for determining whether there is a possibility of a misread tag.
(B) Means for selecting a tag ID having a received signal strength smaller than the threshold from the IDs received so far.
(C) Means for performing individual reading of a tag for the selected ID.

Embodiment 3 FIG.
Next, in the present embodiment, an example will be described in which the tag group 6 has a larger number of tags and tags are read while switching a plurality of antennas.
In this case, every time the antenna is switched, InventoryTags is processed.
In other words, after performing the InventoryTags a plurality of times, “misread tags” are detected.
Hereinafter, description will be made with reference to FIGS.

The configuration of the entire RFID system is shown in FIG.
Although the main part is the same as FIG. 1, there are two antennas 41 and 42.
Accordingly, the reader device 2 has the antenna switching device 24, and the antennas 41 and 42 are connected to the antenna cables 51 and 52, respectively, and are connected to the antenna switching device 24. The antennas 41 and 42 alternately read the ID from the tag.
Further, the tag group 6 also includes 601a, 601b, 601c, 601d, 601e, 601f, 602a, 602b,. . . . , 610a, 610b, 610c, 610d, 610e, 610f and 10 rows × 6 columns = 60.
The physical arrangement of the tag group 6, the antennas 41 and 42, and the non-target tag 8 is as shown in FIG.
The tag group 6 reads all the tags while passing between the antenna 41 and the antenna 42.
At this time, the rows a, c, and e are pasted toward the antenna 41, and the rows b, d, and f are pasted toward the antenna 42.
FIG. 11 shows the state of switching of the antenna of the reader device, execution of InventoryTags, and accumulation of the tag number R for each InventoryTags.

In FIG. 11, in S01, the round control unit 223 initializes the read tag number T to zero. Also, the number I of InventoryTags is initialized to zero.
In S02, the round control unit 223 designates the antenna 41. At this time, the antenna switching device 24 in FIG. 9 is connected to the antenna cable 51.
In S12, I-th InventoryTags are executed. Details follow the flowchart of FIG.
In S <b> 13, the number of tags R [I] read by the I-th InventoryTags is recorded in the memory 224. Further, I is incremented.
In S14, the round control unit 223 reads the number of tags R [I−N], R [I−N + 1],..., R [I−1] read in the past N inventory tags from the memory 224, all of which are 0. If so, it is determined that the reading process has been completed, and the process proceeds to step S15. Usually, N is set to a value of about 2 to 4 in advance.
On the other hand, when all are not 0, the reading process has not been completed, and the process proceeds to step S11.
In S11, the round control unit 223 switches the antenna. If the antenna 41 is currently used, the antenna switching device 24 is connected so as to be connected to the antenna 42. If the antenna 42 is currently used, the antenna switching device 24 is connected so as to connect to the antenna 41.
In S15, the round control unit 223 selects IDs by RSSI. This method follows FIG. 5 as in the first and second embodiments.

Further, FIG. 12 shows details of step S12.
This flowchart is the same as the second embodiment in the main part, but differs in the following three points.
(1) The initialization of T in step S20 in FIG.
(2) In step S26 of FIG. 7, the ID and RSSI are unconditionally stored in the memory. However, in FIG. 12, the ID and RSSI are stored only when the ID is not stored in the memory. Only at this time, T is incremented.
(3) The ID selection process in step S35 of FIG. 7 is unnecessary and has been deleted.
The processes corresponding to step S20 and step S35 in FIG. 7 are deleted in FIG. 12, but the equivalent process is executed in steps S01 and S15 in FIG.

As described above, in this embodiment, the reader device 2 is connected to a plurality of antennas that alternately receive radio signals from the tag, and the RSSI measurement unit 237 wirelessly transmits each time each antenna receives a radio signal. The received signal strength at the time of signal reception is measured, and the ID detection unit 236 detects the tag ID from the received signal of each antenna.
Then, the memory 224 associates the ID detected by the ID detection unit 236 and the received signal strength measured by the RSSI measurement unit 237 with respect to reception of radio signals by a plurality of antennas.
In addition, the round control unit 223 analyzes the received signal strength levels at the plurality of antennas measured by the RSSI measurement unit 237, and determines the misread ID from the IDs detected by the ID detection unit 236.

  As described above, according to the present embodiment, it is possible to eliminate a misread tag (misread ID) with high accuracy even when a plurality of antennas are used for a tag group including a large number of tags.

In the present embodiment, an RFID reader / writer device including the following means has been described.
(A) A plurality of antennas are connected.
(B) Means for switching connection with a plurality of antennas.
(C) InventoryTags are executed a plurality of times in response to a read command from the host computer.
(D) Means for switching antennas each time InventoryTags is executed.
(E) Means for determining a misread tag from tag information (ID, received signal strength) obtained by multiple InventoryTags.

As described above, in the physical distribution management system using the RFID system according to the first to third embodiments, the case where the article (tag group) stops and inspects or the article passes in front of the inspection gate (antenna of the reader device). In the case of inspecting the product, the “misread” of the tag that should not be read in the vicinity is judged and transmitted to the physical distribution management system, so that the malfunction can be prevented.
Furthermore, the above effects can be achieved both when the number of tags to be inspected is known in advance and when it is not known.

Finally, a hardware configuration example of the reader device 2 shown in the first to third embodiments will be described.
FIG. 14 is a diagram illustrating an example of hardware resources of the reader device 2 described in the first to third embodiments.
Note that the configuration of FIG. 14 is merely an example of the hardware configuration of the reader device 2, and the hardware configuration of the reader device 2 is not limited to the configuration illustrated in FIG. 14 and may be other configurations. .

In FIG. 14, the reader device 2 includes a CPU 911 (also referred to as a central processing unit, a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, and a processor) that executes a program.
The CPU 911 is connected to, for example, a ROM (Read Only Memory) 913, a RAM (Random Access Memory) 914, a communication board 915, a display device 901, a keyboard 902, a mouse 903, and a magnetic disk device 920 via a bus 912. Control hardware devices.
Further, the CPU 911 is connected to the antenna 4 via, for example, a reception filter 233 and a circulator 232.
The network interface unit 21 includes a communication board 915, for example.

Further, the CPU 911 may be connected to an FDD 904 (Flexible Disk Drive) or a compact disk device 905 (CDD). Further, instead of the magnetic disk device 920, a storage device such as an optical disk device or a memory card (registered trademark) read / write device may be used.
The RAM 914 is an example of a volatile memory. The storage media of the ROM 913, the FDD 904, the CDD 905, and the magnetic disk device 920 are an example of a nonvolatile memory. These are examples of the storage device.
The memory 224 and the determination reference value storage unit 226 described in the first to third embodiments are realized by the RAM 914, the magnetic disk device 920, and the like.
The communication board 915, the keyboard 902, the mouse 903, the FDD 904, and the like are examples of input devices.
The communication board 915, the display device 901, and the like are examples of output devices.

  The communication board 915 may be connected to, for example, a LAN (Local Area Network), the Internet, a WAN (Wide Area Network), a SAN (Storage Area Network), or the like.

The magnetic disk device 920 stores an operating system 921 (OS), a program group 923, and a file group 924.
The programs in the program group 923 are executed by the CPU 911 using the operating system 921.

The RAM 914 temporarily stores at least part of the operating system 921 program and application programs to be executed by the CPU 911.
The RAM 914 stores various data necessary for processing by the CPU 911.

The ROM 913 stores a BIOS (Basic Input Output System) program, and the magnetic disk device 920 stores a boot program.
When the reader device 2 is activated, the BIOS program in the ROM 913 and the boot program in the magnetic disk device 920 are executed, and the operating system 921 is activated by the BIOS program and the boot program.

  The program group 923 stores programs that execute the functions described as “˜parts” in the description of the first to third embodiments (except for the determination reference value storage unit 226). The program is read and executed by the CPU 911.

In the file group 924, in the description of the first to third embodiments, “determination of”, “selection of”, “selection of”, “determination of”, “classification of”, and “setting of” are set. ”,“ Registration of ”,“ Analysis of ”,“ Measurement of ”,“ Extraction of ”,“ Detection of ”, etc. Values and parameters are stored as items of “˜file” and “˜database”.
The “˜file” and “˜database” are stored in a recording medium such as a disk or a memory. Information, data, signal values, variable values, and parameters stored in a storage medium such as a disk or memory are read out to the main memory or cache memory by the CPU 911 via a read / write circuit, and extracted, searched, referenced, compared, and calculated. Used for CPU operations such as calculation, processing, editing, output, printing, and display.
Information, data, signal values, variable values, and parameters are stored in the main memory, registers, cache memory, and buffers during the CPU operations of extraction, search, reference, comparison, calculation, processing, editing, output, printing, and display. It is temporarily stored in a memory or the like.
In addition, arrows in the flowcharts described in the first to third embodiments mainly indicate input / output of data and signals, and the data and signal values are the memory of the RAM 914, the flexible disk of the FDD904, the compact disk of the CDD905, and the magnetic field. Recording is performed on a recording medium such as a magnetic disk of the disk device 920, other optical disks, mini disks, DVDs, and the like. Data and signals are transmitted online via a bus 912, signal lines, cables, or other transmission media.

In addition, what is described as “˜unit” in the description of the first to third embodiments may be “˜circuit”, “˜device”, “˜device”, and “˜step”, It may be “˜procedure” or “˜processing”.
That is, the data processing method according to the present invention can be realized by the steps, procedures, and processes shown in the flowcharts described in the first to third embodiments.
Further, what is described as “˜unit” may be realized by firmware stored in the ROM 913. Alternatively, it may be implemented only by software, or only by hardware such as elements, devices, substrates, and wirings, by a combination of software and hardware, or by a combination of firmware. Firmware and software are stored as programs in a recording medium such as a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, and a DVD. The program is read by the CPU 911 and executed by the CPU 911. That is, the program causes the computer to function as “to part” in the first to third embodiments. Alternatively, the computer executes the procedure and method of “to part” in the first to third embodiments.

  As described above, the reader device 2 described in the first to third embodiments includes a CPU that is a processing device, a memory that is a storage device, a magnetic disk, a keyboard that is an input device, a mouse, a communication board, and a display device that is an output device, and a communication board. As described above, the function indicated as “to part” is realized by using these processing device, storage device, input device, and output device.

  1 host computer, 2 reader device, 3 network, 4 antenna, 5 antenna cable, 6 tag group, 7 cart, 8 non-target tag, 21 network interface unit, 22 communication control unit, 23 wireless communication unit, 24 antenna switching device, 28 sensor, 41 antenna, 42 antenna, 51 antenna cable, 52 antenna cable, 221 command analysis unit, 222 command generation unit, 223 round control unit, 224 memory, 225 response generation unit, 226 determination reference value storage unit, 231 transmission signal Conversion unit, 232 circulator, 233 reception filter, 234 HandleNumber detection unit, 235 co-region detection unit, 236 ID detection unit, 237 RSSI measurement unit.

Claims (7)

The wireless tag is connected to an antenna that receives a wireless signal including the wireless tag ID (Identification).
Each time the antenna receives a radio signal, a received signal strength measuring unit that measures the received signal strength at the time of radio signal reception;
An ID detection unit for detecting an ID of the wireless tag from a reception signal of the antenna;
An ID strength association unit that associates the ID detected by the ID detection unit with the received signal strength measured by the received signal strength measuring unit;
An ID reception target number storage unit that stores the number of wireless tags that are ID reception targets as an ID reception target number;
The received signal strength level measured by the received signal strength measuring unit is analyzed , the IDs are ranked in order of the received signal strength, and the ID detected by the ID detecting unit is lower than the number of ID reception targets. data processing for the ID is in the order, characterized in that it has a misreading ID determination unit did not become a subject of ID received to misread ID and determine the constant from the wireless tag had been received ID erroneously apparatus. The wireless tag is connected to an antenna that receives a wireless signal including the wireless tag ID (Identification).
Each time the antenna receives a radio signal, a received signal strength measuring unit that measures the received signal strength at the time of radio signal reception;
An ID detection unit for detecting an ID of the wireless tag from a reception signal of the antenna;
An ID strength association unit that associates the ID detected by the ID detection unit with the received signal strength measured by the received signal strength measuring unit;
The received signal strength level measured by the received signal strength measuring unit is analyzed, and the ID detected by the ID detecting unit is not a target of ID reception, but an ID is received by mistake. A misread ID discriminating unit that discriminates a misread ID from a radio tag that has been trapped, extracts a received signal strength less than a predetermined level, and classifies the ID associated with the extracted received signal strength as a re-receiving target ID. Yes, and
The antenna is
Re-receiving the wireless signal from the wireless tag having the re-receiving target ID classified by the misread ID determining unit,
The received signal strength measuring unit is
Measure the received signal strength at the time of wireless signal re-reception from the wireless tag having the re-receiving object ID,
The misread ID discrimination unit
Analyzing at least one of the received signal strength at the time of re-receiving from the wireless tag having the re-receiving target ID and the received signal strength at the time of initial reception to determine whether or not the re-receiving target ID is a misread ID the data processing apparatus characterized that you. The misread ID discrimination unit
If the received signal strength at the time of re-receiving from the wireless tag having the re-receiving target ID exceeds the received signal strength at the time of initial reception, the received signal strength at the time of re-receiving is analyzed, and the re-receiving target ID is The data processing apparatus according to claim 2 , wherein it is determined whether the ID is a misread ID. The data processing device further includes:
A threshold storage unit that stores a threshold for distinguishing from the received signal strength of a wireless signal from a wireless tag that is an ID reception target;
The misread ID discrimination unit
The data processing apparatus according to claim 1 or 2, characterized in that said extracting received signal strength below a threshold value, determines that the extracted misreading ID the ID associated with the received signal strength. The data processing device includes:
It is connected to multiple antennas that receive radio signals from radio tags in turn,
The received signal strength measuring unit is
Every time each antenna receives a radio signal, measure the received signal strength when receiving the radio signal,
The ID detection unit
The ID of the wireless tag is detected from the received signal of each antenna,
The ID strength association unit
For reception of radio signals by the plurality of antennas, the ID detected by the ID detection unit is associated with the reception signal strength measured by the reception signal strength measurement unit,
The misread ID discrimination unit
2. The misread ID is discriminated from the ID detected by the ID detection unit by analyzing the level of the received signal strength at the plurality of antennas measured by the received signal strength measurement unit. Or the data processing apparatus of 2. A data processing method performed in a data processing apparatus connected to an antenna that receives a radio signal including an ID (Identification) of a radio tag from a radio tag,
Each time the antenna receives a radio signal, the data processing device measures a received signal strength when measuring the received signal strength when receiving the radio signal; and
An ID detection step in which the data processing device detects an ID of a wireless tag from a reception signal of the antenna;
An ID strength associating step in which the data processing device associates the ID detected in the ID detecting step with the received signal strength measured in the received signal strength measuring step;
The data processing device analyzes the level of the received signal strength measured in the received signal strength measuring step , ranks the IDs in the order of the received signal strength, and receives the ID received from the IDs detected in the ID detecting step. ID is in the lower rank than the ID reception target number is the number of radio tag to be, and misreading ID from the radio tag ID by mistake but had not been the subject of ID received have been received data processing method characterized by having a misreading ID determination step of determine a constant. From a wireless tag, to a computer connected to an antenna that receives a wireless signal including the wireless tag ID (Identification),
Every time the antenna receives a radio signal, a received signal strength measurement process for measuring the received signal strength at the time of receiving the radio signal;
ID detection processing for detecting the ID of the wireless tag from the received signal of the antenna;
ID strength association processing for associating the ID detected by the ID detection processing with the received signal strength measured by the received signal strength measurement processing;
The received signal strength level measured by the received signal strength measurement process is analyzed , the IDs are ranked in the order of the received signal strength, and among the IDs detected by the ID detecting step , the wireless tag that is the target of ID reception ID is in the lower rank than ID reception target number is the number of erroneous reading was not the subject of ID receiving misreading ID and determine the constant from the wireless tag had been received ID erroneously ID determination A program characterized by causing processing to be executed.

Images