JP2000068924A - Information read system, radio medium used for the same, reader and information read method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the time for recognizing read completion and to speed up processing by setting a common slot in the prescribed position of a transmission slot from a reader by a multi-read system, recognizing it and making a response in the common slot. SOLUTION: A reader broadcast a read command containing the description of the number of used time slots and respective data carriers simultaneously transmit ID data with a common slot at the head of a transmission frame by receiving the command, select the arbitrary slot from a plurality of time slots and transmit ID data. The reader CRC-checks received ID data and records normal ID data. Recognized data is sent to the data carrier which normally receives data after a prescribed time passes and the carrier receiving it stops the subsequent response. The process is repeated and the read of all data carriers is judged to be completed when the transmission of ID data in the common slot is not performed. Thus, the time required for recognition can be shortened by one frame.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information reading system for reading data by a multi-read system,
The present invention relates to a wireless medium, a reading device, and an information reading method used in the information reading system.

[0002]

2. Description of the Related Art An information reading system is a kind of wireless communication system which reads information recorded on a data carrier (Data Carrier) called a so-called wireless tag via a wireless communication and executes various applications. It is. This type of system is a mobile object identification device,
It is called an RF-ID, a remote ID, a wireless card, or the like, and is planned to be applied to, for example, a railway ticket, a non-stop toll on a highway, and the like.

As shown in FIG. 5, an information reading system comprises a data carrier (DC) 11 to 1n, a reader (reading device) 2 for reading information recorded on the data carrier DC 11 to 1n, and a reader 2 A host computer 3 that executes various applications using the read information.

[0004] By the way, the reader 2 has a data carrier DC.
Method (protocol) for reading data of 11 to 1n
There are a single read system and a multi read system. The single read method means that one data carrier DC is simultaneously placed in the radio wave area of the reader 2 (within 0 to 2 m).
This is a method for executing an application that only exists. In this method, since the reader 2 only needs to sequentially read the data of the data carrier DC that sequentially arrives in the radio wave area, there is no particular difficulty regarding the protocol.

On the other hand, the multi-read system is a system for executing an application in which a plurality of data carriers DC exist simultaneously in a radio wave area. In such a case, there is a possibility that different data carriers transmit data at the same time and a collision occurs. Therefore, a procedure for completing data reading for all data carriers in a short time while avoiding the collision as much as possible is considered. Stipulated.

The procedure of the conventional information reading system using the multi-read method will be described with reference to FIG.
Here, it is assumed that each of the data carriers (DC) 11 to 1n transmits its own identification information (ID) to the reader 2. First, the reader 2 broadcasts a read command to each of the DCs 11 to 1n (step ST41).
In this read command, the number of used time slots (for example, 8) is described in accordance with the (expected) number of DCs 11 to 1n.
Selects any one of the eight slots (by backing off) and transmits ID data to the reader 2 (step ST42). Here, DC11 to DC1
Since n randomly selects a slot, the possibility of collision is reduced.

[0007] The reader 2 receives the ID data from the DCs 11 to 1n and performs a CRC check. Here, if an error occurs, the data is discarded as a collision has occurred,
If normal, the ID data is recorded. And 8
After the time for the slot has elapsed, confirmation data indicating that reception is OK is transmitted to the data carrier that has successfully received the ID data (step ST43).

[0008] The confirmation data includes the ID of the destination data carrier, and upon receiving the confirmation data, the data carrier transmits a confirmation response to the reader 2 and stops responding to the subsequent read command (step ST4).
4). In the process up to this point, a collision may have occurred, and data carriers from which ID data could not be read may remain. Therefore, the process from step ST41 to step ST44 is repeated (step ST45),
The ID reading process is completed when there is no response (ID transmission) from all the data carriers DC11 to 1n.

FIG. 7 shows a time chart of the above processing. In this figure, the number of data carriers is described as four. As a result of back-off (abbreviated as BO) in DC1 to DC4, DC1 and DC4 become slots S3 and DC2.
Assume that slot S7 and DC3 have acquired slot S5, respectively, and a collision occurs in slot S3. Therefore, DC1 and DC4 are backed off again by the next read command, and transmit ID data.

The host computer 3 shown in FIG. 5 performs various data processing after all the DCs 11 to 1n have been read. For this reason, in order to increase the processing efficiency, it is necessary to shorten the time required to complete the reading as much as possible.

However, the above process has a disadvantage that it takes a wasteful time to complete the reading. The reason will be described below. For example, suppose that after repeating the frame shown in FIG. 7 several times, there was no collision in any of the slots and data reading could be performed.
However, here, the data of all the data carriers 11 to 1n is not necessarily read. This is because even if a collision occurs in a wireless section due to the state of radio waves, data from one of the data carriers may be read normally.
When the ID data of C11 to 1n is read, it cannot be determined (on the reader 2 side).

Therefore, in order to determine the completion of reading from all the DCs 11 to 1n, it is necessary to confirm that ID data has not been transmitted to all slots. That is, the reader 2 cannot know that the ID data has been successfully read from the last data carrier (the reading has already been completed) at this point, and after the remaining slots have been consumed, all the DCs 11 are again read. It is necessary to send a read command to .about.1n and then confirm that all slots have no response.

That is, although ID data reading for all DCs 11 to 1n has already been completed,
It will take extra time for the frame. Of course, as the number of slots increases, this wasted time becomes even longer. This is not preferable because it hinders the improvement of the processing efficiency.

[0014]

As described above, the conventional reading method of the multi-read system requires one frame of useless time to confirm the completion of reading, and thus has the disadvantage of low processing efficiency. there were.

The present invention has been made in view of the above circumstances,
An object of the present invention is to provide an information reading system capable of shortening a time required for completing data reading and thereby speeding up a process, a wireless medium used in the information reading system, a reading device, and an information reading method. is there.

[0016]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a plurality of wireless media for transmitting, via radio waves, identification information given in advance in response to a response request given from the outside; Forming a radio wave area in the area, and a reading device for acquiring identification information of the wireless medium located in the radio wave area, wherein the reading device is provided with a plurality of the wireless media located in the radio wave area. Sending the response request to the wireless medium for which the transmission of the identification information is urged, and sending a response stop request to the wireless medium for which the acquisition of the identification information has been completed, and the wireless medium for which the acquisition of the identification information has not been completed. In the information reading system for acquiring the identification information of all the wireless media located in the radio wave area by transmitting the response request again to the wireless media, Among the plurality of slots in the transmission frame of the uplink towards the reader,
A common slot predefined at a predetermined position, and transmission slot control means for responding to the reader using an arbitrarily selected individual slot in its own device, the reader, monitoring the common slot,
If the response is not received in the common slot, read completion determination means is provided for determining that information reading has been completed for all wireless media located in the radio wave area.

By adopting such means, transmission of identification information from a plurality of data carriers (wireless media) is performed, for example, in a common slot at a predefined position (for example, the head) among eight transmission slots. All at once,
And individually in slots at other positions (arbitrarily determined by backoff in each data carrier). That is, each data carrier transmits the identification information twice within one transmission frame period.

On the other hand, the reader (reading device) monitors the above-mentioned common slot, and when no transmission information from the data carrier is received in this common slot,
It is determined that information reading has been completed for all the wireless media located within the radio wave area of the own device.

As described above, since a common slot is provided between data carriers in a transmission frame, it is possible to know that reading has been completed when information is not transmitted from a data carrier in this common slot. it can. As a result, the time required to complete the data reading is reduced, and the processing can be speeded up.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings. In this embodiment, the same system configuration as that of FIG. 5 is assumed. However, since the configurations of the data carrier and the reader are different, the data carriers are denoted by reference numerals 101 to 10n and the reader is denoted by reference numeral 200. FIG. 1 is a block diagram showing a configuration of data carriers 101 to 10n according to the embodiment of the present invention. Data carriers 101 to 10 according to the present embodiment
n is an RF unit 42 having an antenna 41 and a power unit 43
, A media access controller (hereinafter, referred to as a MAC), a CPU (central processing unit) 45, and a memory 46.

That is, a radio frequency signal arriving from a reader 200 (not shown) is transmitted to the RF unit 4 via the antenna 41.
2 and the received signal is supplied to the power supply 43 and M
Input to AC44. In the power supply unit 43, driving power for the MAC 44, the CPU 45, and the memory 46 is extracted from the received signal power. The CPU 45 executes various control procedures related to information communication with the reader 200 based on the operation program stored in the memory 46,
Operation control for the MAC 44 is also performed. In the memory 46,
In addition to the above operation program, it stores identification information such as an identification number assigned to itself (data carrier).

Here, the MAC 44 includes transmission slot control means 44a in addition to a known control procedure relating to information communication with the reader 200. The transmission slot control unit 44a uses the first slot in the transmission frame and the slot determined by backing off randomly by itself to perform transmission on the uplink to the reader 200. Data transmission is performed.

FIG. 2 is a block diagram showing a configuration of the reader 200 according to the embodiment of the present invention. The reader 200 according to the present embodiment includes an RF module 22 having an antenna 21, a control module 23, an interface unit (I / F) 24 for interfacing with the host computer 3, and a storage unit 25. I have.

That is, the data carriers 101 to 10n
The radio frequency signal arriving from
The data is received by the F module 22, transferred to the control module 23, and subjected to data acquisition processing. This data is transferred to the host computer 3 via the interface unit (I / F) 24, and various applications are executed. The processing in the control module 23 is executed based on a program stored in the storage unit 25.

Here, the control module 23
In addition to a known processing function related to information communication between the data carriers 101 to 10n and the host computer 3, a reading completion determination unit 23a is provided. The read completion determining means 23a includes the data carriers 101 to
It monitors the slot located at the beginning of the transmission frame in the uplink from 10n, and if it does not receive its own transmission information in this head slot,
Data carriers 101 to 10n located in the radio wave area
It is determined that the information reading for all of has been completed.

Next, the operation of the present embodiment will be described with reference to FIGS. FIG. 3 is a diagram showing an operation flow between the data carriers 101 to 10n to the reader 200 in the present embodiment. In this embodiment, it is assumed that the data carriers 101 to 10n transmit their ID data to the reader 200.

In FIG. 3, first, the reader 200 broadcasts a read command to each of the data carriers 101 to 10n (step ST31). In this read command, the number of used time slots (for example, eight) is described according to the (expected) number of the data carriers 101 to 10n.

In response to this, all data carriers 10
1 to 10n simultaneously transmit ID data to the reader 200 in the first slot (common slot) of the transmission frame (step ST32). In step ST32, the reader 200 detects a carrier in the common slot.

Subsequently, the data carriers 101 to 10n
Selects any one of the eight slots (by backing off) and transmits ID data to the reader 200 (step ST33).

The reader 200 includes data carriers 101 to
It receives the ID data from 10n and performs a CRC check. Here, if an error occurs, the data is discarded on the assumption that a collision has occurred, and if normal, the ID data is recorded. And after the time of 8 slots has passed,
Confirmation data indicating that the reception is OK is transmitted to the data carrier that has successfully received the ID data (step ST34).

The confirmation data contains the ID of the destination data carrier. The data carrier receiving this transmits a confirmation response to the reader 200, and then stops responding to the subsequent read command (step ST3).
5). In the process up to this point, a collision may have occurred, and data carriers from which ID data could not be read may remain. Therefore, the process from step ST31 to step ST35 is repeated (step ST3).
6).

Then, in response to the transmission of the read command from the reader 200 (step ST37), it is determined that there is no transmission of ID data in the common slot (step S37).
T38), the data reading of all the data carriers 101 to 10n is completed.

FIG. 4 shows a time chart of the above processing. In this figure, the number of data carriers is 4 (DC1 to DC1).
DC4). That is, the reader 20
0 to each of the DC1 to DC4
Is the first slot (S1) and the respective backoff (B
O) The ID data is transmitted in each of the performed slots. Here, since both DC1 and DC4 have acquired slot S3, a collision has occurred in this slot. Therefore, DC1 and DC4 back off again in the next transmission frame and transmit ID data.

As described above, in the present embodiment, in the uplink transmission frame from the data carriers 101 to 10n to the reader 200, each data carrier 101
In addition to the slots acquired by backing off by each of the data carriers 101 to 10n independently, a slot (common slot) in which all the data carriers 101 to 10n commonly transmit ID data is set at the head position of the transmission frame. In the slot, I from each data carrier 101-10n
When the D data has not been transmitted, the reading of the ID data of all the data carriers is completed.

With this configuration, the time required to complete the data reading can be reduced by the time from the first slot to the last slot, and the processing can be speeded up.

The present invention is not limited to the above embodiment. For example, in the present embodiment, the ID data of each of the data carriers 101 to 10n is transmitted in the common slot. However, since the common slot is used only for detecting the presence or absence of the carrier, the ID data is transmitted. The type of information does not matter. Further, the common slot can be set not only at the head position of the frame but also at another position. In addition, various modifications can be made without departing from the spirit of the present invention.

[0037]

As described in detail above, according to the present invention, it is possible to shorten the time required for completing the data reading, and thereby the information reading system which can speed up the processing, and the information reading system. It is possible to provide a wireless medium, a reading device, and an information reading method used for the present invention.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a data carrier according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a reader according to the embodiment of the present invention.

FIG. 3 shows data carriers according to an embodiment of the present invention.
The figure which shows the operation | movement flow between readers.

FIG. 4 shows data carriers according to the embodiment of the present invention.
6 is a time chart showing a process between readers.

FIG. 5 is a diagram showing a configuration of an information reading system.

FIG. 6 is a diagram showing a message flow in a conventional multi-read system.

FIG. 7 is a time chart showing a processing process in a conventional multi-read system.

[Explanation of symbols]

 11 to 1n Data carrier (DC) 2 Reader (reading device) 101 to 10n Data carrier 200 Reader (reading device) 21 Antenna 22 RF module 23 Control module 23a Read completion determination means 24 Interface unit (I / F) 25 storage unit 3 host computer 41 antenna 42 RF unit 43 power supply unit 44 media access controller (MAC) 44a transmission slot control unit 45 CPU 46 memory

Claims (7)

[Claims] 1. A plurality of wireless media for transmitting identification information given in advance through radio waves in response to a response request given from the outside, a radio wave area formed in a predetermined area, and a radio wave area located in the radio wave area. A reader for acquiring the identification information of the wireless medium, wherein the reader sends the response request to the plurality of wireless media located in the radio wave area, thereby transmitting the identification information. By sending a response stop request to the wireless medium for which the acquisition of the identification information has been completed, and again sending the response request to the wireless medium for which the acquisition of the identification information has not been completed, In an information reading system for acquiring identification information of all wireless media located in a radio wave area, each of the wireless media includes an uplink transmission stream directed to the reader. Transmission slot control means for responding to the reading device by using a common slot predefined at a predetermined position and an individual slot arbitrarily selected in the own device, among the plurality of slots in the reading device, The read completion determining means for monitoring the common slot, and when not receiving the response in the common slot, determining that information reading for all wireless media located in the radio wave area is completed. An information reading system, comprising: 2. The information reading system according to claim 1, wherein the position of the common slot in the transmission frame is set at the beginning of the transmission frame. 3. A plurality of wireless media for transmitting pre-assigned identification information via a radio wave in response to a response request given from the outside, a radio wave area formed in a predetermined area, and an area located within the radio wave area. A reading device for acquiring identification information of the wireless medium, wherein the reading device sends the response request to the plurality of wireless media located within the radio wave area, thereby transmitting the identification information. By sending a response stop request to the wireless medium for which the acquisition of the identification information has been completed, and again sending the response request to the wireless medium for which the acquisition of the identification information has not been completed, The wireless medium used in an information reading system that acquires identification information of all wireless mediums located in a radio wave area, wherein the wireless medium includes an uplink for the reading device. Among a plurality of slots in the transmission frame, a transmission slot control means for responding to the reading device using a common slot predefined at a predetermined position and an individual slot arbitrarily selected in the own device. Wireless medium to do. 4. The wireless medium according to claim 3, wherein the position of the common slot in the transmission frame is set at the beginning of the transmission frame. 5. A plurality of wireless media for transmitting, via radio waves, identification information given in advance in response to a response request given from the outside, a radio wave area formed in a predetermined area, and a radio wave area located in the radio wave area. And a reading device that obtains identification information of the wireless medium. The reading device transmits the response request to a plurality of the wireless media located in the radio wave area. By prompting the transmission, a response stop request is transmitted to the wireless medium for which the acquisition of the identification information is completed, and the response request is transmitted again to the wireless medium for which the acquisition of the identification information is not completed, In the reading device for acquiring identification information of all wireless media located in the radio wave area, an uplink transmission frame from the wireless medium to the own device. Of the plurality of slots in the above, monitor a pre-defined common slot at a predetermined position, and if a response addressed to the own device is not received in this common slot, all the radio media located in the radio wave area A reading device comprising: a reading completion determination unit that determines that information reading has been completed. 6. The reading device according to claim 5, wherein the position of the common slot in the transmission frame is set at the beginning of the transmission frame. 7. A plurality of wireless media for transmitting pre-assigned identification information via radio waves in response to a response request given from the outside, a radio wave area formed in a predetermined area, and a radio wave area located in the radio wave area. A reading device for acquiring identification information of the wireless medium, wherein the reading device sends the response request to the plurality of wireless media located within the radio wave area, thereby transmitting the identification information. By sending a response stop request to the wireless medium for which the acquisition of the identification information has been completed, and again sending the response request to the wireless medium for which the acquisition of the identification information has not been completed, An information reading method in the reading device used in an information reading system that obtains identification information of all wireless media located in a radio wave area, In the uplink transmission frame from the linear medium to the reader, in addition to the slots obtained by backing off each wireless medium independently, a common slot that is commonly accessed by all wireless mediums is set. An information reading method, wherein reading of information from all wireless media located within the radio wave area is completed when no access to the common slot is performed from each wireless medium.