JP2008244827A - Wireless authentication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify the installation work of a sensor when communications are performed with a wireless tag by time division multiple access using a common wireless communication band between each individual sensors in a wireless authentication system where a plurality of sensors are arranged along the moving space of a detection object such that the detection object areas overlap partially between the sensors and a wireless tag carried by the detection object performs communications with one of the sensors thus detecting the movement of the detection object. <P>SOLUTION: A first sensor S1 transmits slot No. 1 used by itself as a notification of using slot, subsequent sensors S2 and S3 detect open slots excepting the slot No. 1 and similarly transmit slot No. 2 as a notification of using slot. When collision of notifications is detected by the sensor S1, selection of slot is retried. Consequently, setting can be performed automatically not to use the same slot between adjoining sensors. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, a detection target such as a user carrying a wireless tag (slave station) or a product to which the wireless tag is attached is detected by the wireless tag communicating with a sensor (parent station, reader). In particular, in order to detect the location of the wireless tag and the trajectory passed, a part of each detection target area is mutually connected between sensors adjacent to each other along the movement space of the detection target. It is related with what was arranged so that it might overlap, and it was detected without omission.

  Conventionally, there is a wireless authentication system that performs appropriate services by detecting a wireless tag (slave station) carried by a user or pasted on a product with a sensor (master station, reader) for use in entrance / exit management, etc. in use. For example, it is an entry / exit control system that performs authentication processing with a wireless tag carried by the user and controls opening and closing of a nearby automatic door, or a wireless tag attached to an asset such as a portable computer An asset management system that manages the taking out of assets by detecting with sensors installed at the doorway, or a logistics management system that manages the location of luggage by detecting wireless tags attached to luggage pallets etc. at each logistics base It is.

However, these systems manage moving wireless tags in terms of points, and usually the sensors are spatially separated. However, if you intend to use this wireless tag to manage people and objects on the surface, such as occupancy management and location detection in the office, if you try to detect the wireless tag without any gaps, It is necessary to arrange a plurality of sensors along the target movement space so that a part of each detection target area overlaps between adjacent sensors. In this case, in order to prevent interference of communication with the wireless tag between the sensors, it is conceivable to change the frequency CH to be used for each sensor as in Patent Document 1, for example. In Patent Document 1, when a slave station (wireless tag) detects interference, interference is avoided by causing the master station (sensor) to channel hop.
Japanese Patent No. 3405322

  The above prior art cannot cope with the case of using a method having no frequency CH such as UWB as a communication method with a wireless tag. Further, when many sensors are installed to deal with a wide detection target area or when sensors are added to expand the detection target area, there is a problem that the total number of frequencies CH is limited.

  Therefore, as a method for preventing interference between sensors without dividing the frequency CH, a predetermined period (period) is divided into a plurality of slots, and communication is performed by a TDMA-TDD system in which each sensor uses different slots. It is possible. With this TDMA-TDD system, even if the number of sensors increases, it can be dealt with by increasing the number of slots each time.

  However, even though it can be conveniently operated using the TDMA-TDD method, if each individual time slot is assigned to each sensor in operation, the time length required for one cycle as the number of sensors increases. Will increase the chance of communication with the wireless tag. For this reason, for example, even if a large number of sensors try to contact a user who wants to walk away quickly, a time slot assigned to the sensor (detection target area) during the period in which the user exists in the detection target area May not turn around and may cause detection failure. In order to solve this problem, it is possible to shorten the time length required for one TDMA cycle and increase the number of times the time slot comes as much as possible. The slot cannot be secured. In addition, there is an option of shortening the time length allowed per time slot, but there is a possibility that sufficient information exchange with the wireless tag cannot be performed.

  Therefore, in order to solve such a problem, it is conceivable to assign the same time slot to a sensor in which no interference occurs. However, since the appropriate allocation differs depending on the arrangement of the sensors and the situation of the installation location, it is necessary to consider appropriate slot allocation for each system and set it to each sensor. This is a major obstacle in introducing the system. In addition, when adding a sensor, it may be necessary to change the slot assignment of sensors other than the added sensor.

  An object of the present invention is to provide a wireless authentication system capable of performing slot allocation efficiently and easily.

  The wireless authentication system of the present invention is arranged such that a plurality of sensors are arranged adjacent to each other along a moving space of a detection target so that a part of each detection target area overlaps and is carried by the detection target. In the wireless authentication system in which a tag communicates with one of the sensors to detect movement of the detection target, each sensor communicates with the wireless tag using a common wireless communication band. And a wireless communication unit capable of communicating between adjacent sensors, and a slot to be used by the own device in the wireless communication band, and sending the use slot notification from the wireless communication unit, When the use slot notification is received by the wireless communication unit, a slot selection unit not used for slot selection of the own device is included.

  According to the above configuration, the detection target such as the user carrying the wireless tag or the product to which the wireless tag is attached can be detected along the moving space of the detection target so that the location and the trajectory passed can be detected without omission. The plurality of sensors are arranged so that a part of each detection target area overlaps between adjacent sensors, and the wireless tag carried by the detection target communicates with any one of the sensors. In a wireless authentication system configured to detect movement of a detection target, a slot of each sensor is used to communicate with the wireless tag by time division multiple access (TDMA) using a wireless communication band common to the sensors. The selection unit uses a wireless communication unit that communicates with the wireless tag to enable communication between adjacent sensors, and simply uses a wireless slot in the detection target area of its own device. In the slot setting mode, the slot used by the own device is selected in advance and declared by transmitting to the remaining sensors as a used slot notification from the wireless communication unit. Do not use with other sensors that overlap the detection target area. In another sensor, when the wireless communication unit receives the use slot notification, the slot selection unit searches for another empty slot without using it for slot selection of its own device.

  Therefore, in the wireless authentication system in which the detection target area is continuous in a straight line or a tree shape including appropriate branches, for example, the slot setting is performed when communicating with the wireless tag using a common wireless communication band. When this is done, the slot used is automatically set so as not to use the same slot between adjacent sensors. As a result, it is possible to easily perform new installation work and additional work of the sensor. In addition, since the same slot can be used between sensors that do not overlap the detection target area, even if many sensors are installed in a wide area without interference, the number of slots used is minimized. (The slot allocation is performed efficiently), and the detection period (period in which the slot makes a round) can be shortened to improve the responsiveness.

  Further, in the wireless authentication system of the present invention, the slot selection unit selects a slot to be used by the own device, and transmits a used slot notification, and after transmitting the used slot notification from the own device. When the collision detection notification is received, the slot allocation processing unit is caused to perform an empty slot re-search and the used slot notification retransmission process, and when the used slot notification is received and the notification contents cannot be reproduced, And a collision detection processing unit that transmits a collision detection notification.

  According to the above configuration, after the own device transmits the use slot notification, the next or second use slot notification is received and is duplicated, that is, the own device branches the moving space. If it is located in the part, the detection target areas do not overlap between the next and second sensors, and it is not known that the use slot notifications overlap each other. A collision detection notification is transmitted, and the slot allocation processing unit is again made to search for an empty slot and to transmit a used slot notification.

  Therefore, slot overlap (interference) can be reliably prevented between adjacent sensors.

  Furthermore, in the wireless authentication system of the present invention, a setting button is connected to the slot selection unit, and a slot setting operation is started by operating the setting button, and a slot used by a start button or another sensor is started. When the notification is received, the slot selection is started.

  According to the above configuration, when the setting button is operated, the slot setting mode is set. In this state, when the start button is operated or when a use slot notification is received from another sensor, the search for the empty slot is started. If the search is possible, the empty slot is selected as a slot to be used by the own device as described above, and the used slot notification is transmitted to other sensors.

  Therefore, when the start button of any one of the sensors is operated in a state where all the sensors are set to the slot setting mode, the sensor first starts searching for an empty slot using that as a trigger. When the used slot notification is transmitted, the next sensor adjacent to the sensor starts searching for an empty slot by receiving the used slot notification. In this way, when the start button of one sensor is operated, the slot used can be automatically set to the end sensor automatically like a ripple using that as a trigger.

  In the wireless authentication system of the present invention, the slot allocation processing unit is used from a slot with a higher priority among the empty slots.

  According to the above configuration, if the first slot, the second slot,... Are arranged in descending order of priority, for example, if the detection target areas are arranged in a straight line, for example, The second slot is used repeatedly, and the third slot with the lower priority is not used.

  Therefore, the number of slots used can be minimized as described above (in this case, two slots), and the detection cycle can be shortened to improve the responsiveness.

  Furthermore, in the wireless authentication system of the present invention, when the setting button is operated and a slot setting operation is started, the slot selection unit sends the transmission power and reception to the wireless communication unit rather than during communication with the wireless tag. It is characterized by increasing at least one of sensitivity.

  According to the above configuration, for example, by making the transmission power or the reception sensitivity four times that at the time of communication with the wireless tag, communication between the sensors can be performed up to twice the distance.

  Therefore, even if the sensor intervals are widened so that the detection target areas of the wireless tag overlap, the slot setting can be reliably performed with sufficient communication quality.

  In the wireless authentication system of the present invention, the slot selection unit on the side of transmitting the used slot notification causes the wireless communication unit to perform transmission at a timing corresponding to the used slot notification, and receives the used slot notification. When the used slot notification cannot be demodulated, the slot selection unit on the receiving side determines the used slot notification from the reception timing of the used slot notification in the wireless communication unit.

  According to the above configuration, the side that transmits the used slot notification does not transmit at an arbitrary timing, but transmits at a timing corresponding to the slot, and the reception side receives the above-mentioned due to a low reception level or the like. Even if the used slot notification cannot be demodulated (decoded), if the synchronization is established in the system, the used slot notification can be determined from the reception timing, so the determined slot is used by the upper sensor. Judge as a slot.

  Therefore, even if the sensors are installed with an increased interval, slot setting can be performed reliably.

  As described above, the wireless authentication system of the present invention allows a wireless tag carried by a user carrying a wireless tag or a detection target such as a product with a wireless tag to communicate with any sensor. In the wireless authentication system configured to detect movement of the detection target, a slot used by the own device when communicating with the wireless tag by time division multiple access using a wireless communication band common to the sensors. Is sent to the remaining sensors by sending a use slot notification, so that at least other sensors that overlap the target device and the detection target area are not used.

  Therefore, in the wireless authentication system in which the detection target area is connected in a straight line or a tree shape including branches as appropriate, the slot setting is used when communicating with the wireless tag using a common wireless communication band. When this is done, the slot used is automatically set so as not to use the same slot between adjacent sensors. As a result, it is possible to easily perform new installation work and additional work of the sensor. In addition, since the same slot can be used between sensors that do not overlap the detection target area, even if many sensors are installed in a wide area without interference, the number of slots used is minimized. (The slot allocation is performed efficiently), and the detection period (period in which the slot makes a round) can be shortened to improve the responsiveness.

  In addition, as described above, the wireless authentication system of the present invention receives the use slot notifications in the second and second ranks after the own device has transmitted the use slot notifications. If the aircraft is located at a branching part of the moving space, it is not clear that the detection target areas do not overlap between the next and second sensors, and the use slot notifications overlap each other. The collision detection processing unit transmits a collision detection notification, and causes the slot allocation processing unit to again search for an empty slot and transmit a use slot notification.

  Therefore, slot overlap (interference) can be reliably prevented between adjacent sensors.

  Furthermore, as described above, the wireless authentication system of the present invention enters the slot setting mode by operating the setting button, and when the start button is operated in that state, or when a use slot notification from another sensor is received. When a search for an empty slot is started and the search can be made, the empty slot is selected as a slot to be used by itself as described above, and the used slot notification is transmitted to another sensor.

  Therefore, when the start button of any one of the sensors is operated with all the sensors set to the slot setting mode, the sensor first starts searching for an empty slot using that as a trigger. When the used slot notification is transmitted, the next sensor adjacent to the sensor starts searching for an empty slot by receiving the used slot notification. In this way, when the start button of one sensor is operated, the slot used can be automatically set to the end sensor automatically like a ripple using that as a trigger.

  In addition, as described above, the wireless authentication system of the present invention is used from a slot having a higher priority in the empty slots.

  Therefore, the number of slots used can be minimized, the detection cycle can be shortened, and the responsiveness can be improved.

  Furthermore, as described above, when the slot setting operation is started, the wireless authentication system of the present invention increases at least one of transmission power and reception sensitivity as compared with communication with the wireless tag.

  Therefore, even if the sensor interval is widened so that the detection target areas of the wireless tag overlap, the slot setting can be reliably performed with sufficient communication quality.

  In the wireless authentication system of the present invention, as described above, the side that transmits the used slot notification does not transmit at an arbitrary timing, but transmits at a timing corresponding to the slot, and on the receiving side. Even if the use slot notification could not be demodulated (decoded) due to a low reception level, etc., the use slot notification can be determined from the reception timing if synchronization within the system is established. The slot is determined to be a used slot of the upper sensor.

  Therefore, the slot can be set reliably even when the sensors are installed with a wide interval.

[Embodiment 1]
FIG. 1 is a block diagram showing a configuration of a wireless authentication system according to an embodiment of the present invention. In this wireless authentication system, a plurality of sensors S1, S2, S3, S4,... (Referred to collectively as reference numeral S hereinafter) are arranged along the moving space 1 of the user to be detected, The wireless tag TG carried by the user communicates with one of the sensors S, and the detection result is monitored by the host device 2 so that the host device 2 detects the location of the user and the trajectory passed. Is. Each sensor S is mounted on a ceiling or the like, and its detection target areas A1, A2, A3, A4,... (Generally referred to as reference numeral A below) detect such users without omission. In order to be able to do so, it arrange | positions so that the one part may mutually overlap between adjacent sensors S. FIG. The wireless tag TG can be detected by the sensor S having the detection target area A as long as it moves within the detection target area A.

  In the present embodiment, when each sensor S communicates with the wireless tag TG by the TDMA-TDD system using a common wireless communication band, each sensor S uses a time slot used for communication. It should be noted that the slot setting is automatically set so that each sensor S can avoid interference in response to an operation of a setting button, which will be described later, or a wireless (remote control) setting instruction. To do.

  Each of the sensors S uses a UHF band or the like for communication, and its detection target area A is usually about 7 m in diameter in order to prevent interference between adjacent sensors. In the setting mode by addition or the like, by increasing at least one of the transmission power and the reception sensitivity, for example, the transmission power or the reception sensitivity is quadrupled, and in FIG. 1, reference numerals A1 ′, A2 ′, A3 ′, A4 ′ ,... (When collectively referred to as reference symbol A ′ below), the reach is doubled, and the sensors S may be spaced apart so that the detection target areas A overlap with each other. The slot setting can be surely performed with sufficient communication quality.

  Specifically, the increase in the transmission power can be easily realized by increasing the gain of the transmission amplifier. On the other hand, the increase in reception sensitivity can be realized by, for example, reducing the directivity of the antenna or switching to a method with a low communication speed but high sensitivity in order to increase only the signal level without increasing noise. Increasing the reception sensitivity is preferable because the interval between the sensors S can be increased when the transmission power cannot be increased due to restrictions on the circuit and restrictions on communication standards and regulations.

  FIG. 2 is a timing chart for explaining the slot setting operation of each sensor S. In setting, as described above, each sensor S is in the setting mode by the operation of the setting button or the setting instruction by wireless, and the operator selects an arbitrary sensor, preferably a sensor located at the end of the sensor array ( In the example of FIGS. 1 and 2, S1) is selected, and the setting operation is started from the sensor S1 in response to an operation of a start button or a start instruction by the wireless (remote control). In the setting operation, first, an empty slot in the wireless communication band is searched, and if it is detected, the slot with the highest priority (No. 1 in the example of FIG. 2) is selected and used by the own device. Assigned to a slot, the slot No. 1 is sent to other sensors as a use slot notification.

  Accordingly, in the example of FIGS. 1 and 2, when the subsequent sensors S2 and S3 receive the slot notification, the sensors S2 and S3 also start the setting operation using the notification as a trigger. 1 is not used for its own slot allocation, and other slots are similarly searched for empty slots, and when detected, the slot with the highest priority (No. 2 in the example of FIG. 2) is selected. Assigned to the slot to be used by the own device. 2 is transmitted to other sensors as a use slot notification.

  At this time, in the example of FIG. 1 and FIG. 2, the sensor S1 is located at the branching portion of the moving space 1, and the sensors cascaded to the sensor S1 are the two sensors S2 and S3 as described above. In S1, use slot notifications are simultaneously transmitted from two sensors, and data cannot be reproduced due to a collision. The sensor S1 that has detected the collision transmits a collision detection notification to the other sensors S2 and S3. The collision detection notification is made based on only the reception timing so that it can be detected even if it collides with a notification from another sensor. Specifically, within one transmission cycle W1, a window for a predetermined period W2 after transmission of the use slot notification is set is set, and when a signal of a certain length or more is received in the window, a collision detection notification It is determined that During this window, the used slot notification is not transmitted.

  When the collision is detected in this way, the sensors S2 and S3 end the window and when the next transmission cycle W1 is reached, while avoiding a collision with other sensors while performing carrier sensing by a method such as normal CSMA-CA, The used slot notification is transmitted again. In the example of FIG. 2, after the next transmission cycle W1, the sensors S2 and S3 start transmission after waiting for an arbitrary time in the CSMA-CA method, and are used from the sensor S2 having a short standby time. The slot notification is prioritized, and the sensor S2 is assigned the slot No. for the time being. 2 is assigned to its own slot. At this time, when the sensor S3 having a long standby time detects the use slot notification from the sensor S2 by the carrier sense of the CSMA-CA method, the sensor S3 executes the use slot notification process again. Slot No. 2 and the previously received slot number. 1 is not used for the slot assignment of its own device, and other slots are searched for empty slots in the same manner. If detected, the slot with the highest priority (No. 3 in the example of FIG. 2) is detected. Select and assign it to the slot to be used by its own device. 3 is transmitted to other sensors in the next transmission cycle W1 as a use slot notification.

  As a result, when the transmission of the used slot notification is completed without a collision, the used slots of the sensors S2 and S3 are set to the above-described Nos. 2 and no. 3 and the subsequent sensors (S4 in the example of FIG. 2) start the setting operation. At this time, in the sensor S4, the arrival ranges A1 ′, A2 ′; A4 ′ of the signals related to the sensors S1, S2 do not overlap, that is, the sensor S4 receives the use slot notification transmitted by the sensors S1, S2. The slot No. used by the adjacent sensor S3 is not. Only 3 is recognized. Therefore, when a slot having a higher priority is selected from other slots, the slot No. 1

  Thus, between the adjacent sensors S1 and S4, the used slot No. By allowing 1 to overlap, the number of slots used is minimized (slot allocation is performed efficiently) even when many sensors are installed in a wide area without interference, and the detection cycle It is possible to improve the responsiveness by shortening the (cycle in which the slot makes a round).

  On the other hand, the slot setting operation may be terminated by a timeout process when the use slot notification or the collision detection notification is not received for a predetermined time, and may be terminated by operating the setting button again. Alternatively, the setting end notification may be sequentially transferred by the end operation to the sensor (S1 in the example of FIGS. 1 and 2) in which the start button is operated.

  FIG. 3 is a block diagram illustrating a configuration example of the sensor S that realizes the above-described function. This sensor S communicates with other sensors and the wireless tag TG, and the slot as described above between the wireless signal transmission / reception unit 11 which is a wireless communication unit and the other sensor via the wireless signal transmission / reception unit 11. A tag selection unit 12 that performs a setting operation, a user interface 13 that is used for the slot setting operation and the like, and a tag management unit 14 that communicates with and authenticates the wireless tag TG via the wireless signal transmission / reception unit 11. And a network interface 15 that transmits the authentication data obtained by the tag management unit 14 to the host device 2 and receives the control data of the sensor S from the host device 2.

  The slot selection unit 12 first selects a slot to be used by the own device as described above, and transmits a used slot notification to the slot allocation processing unit 21. After transmitting the used slot notification from the own device, the slot detection notification The slot allocation processing unit 21 retransmits the used slot notification, and when the received slot notification is received and cannot be reproduced, the collision detection processing unit 22 that transmits the collision detection notification, A slot synchronization unit 23 for synchronization, a setting end detection unit 24 that determines the end of the slot setting operation, and a transmission / reception slot management unit 25 that controls the entire slot selection unit 12 are configured.

  The user interface 13 displays, for example, that a normal wireless tag TG detection operation is being performed, and that the slot setting operation is being performed, whether the setting operation has been completed normally, or has failed. Status display means 31 for notifying the user by a lamp display or the like, and notifying that an abnormality is generated or a suspicious wireless tag is detected, an alarm is issued or the wireless tag TG can be recognized normally and the door is unlocked. An alarm / notification sound generator 32 such as a buzzer and a setting switch 33 such as the setting button and the start button are provided.

  When the slot setting operation is started by operating the setting button or the start button of the setting switch 33, the empty slot detection processing unit 211 of the slot allocation processing unit 21 searches for an empty slot as described above. The slot having the highest priority is selected and assigned to the slot to be used by the own device. Is transmitted from the used slot notification transmission processing unit 212 to other sensors via the transmission / reception slot management unit 25 and the wireless signal transmission / reception unit 11. On the other hand, the used slot notification received from the radio signal transmitting / receiving unit 11 via the transmission / reception slot management unit 25 is stored in the used slot notification reception processing unit 213 and used for slot selection by the empty slot detection processing unit 211. When the use slot notification is received by the use slot notification reception processing unit 213, if the sensor has not started the slot setting operation, the setting operation is started by using the sensor as a trigger, and the empty slot detection processing unit 211 Starts slot selection.

  The use slot notification transmitted in this way is determined to be a collision when the collision detection unit 221 of the collision detection processing unit 22 cannot reproduce the data as described above, but detects the reception of some data. In response to the determination result, the collision notification transmission processing unit 222 transmits the collision detection notification from the transmission / reception slot management unit 25 via the wireless signal transmission / reception unit 11. On the other hand, when the collision detection notification is received by the collision notification reception processing unit 223 from the wireless signal transmission / reception unit 11 via the transmission / reception slot management unit 25, the retransmission control unit 224 searches the slot allocation processing unit 21 for a free slot. Re-send from.

  In the transmission / reception of these used slot notifications and collision detection notifications, the slot synchronization signal detection processing unit 231 of the slot synchronization unit 23 detects the synchronization such as the transmission cycle W1 from the received data in the transmission / reception slot management unit 25. Synchronization is obtained by the synchronization timing adjustment processing unit 232 controlling the transmission / reception slot management unit 25 so that the timing of the own device matches the system timing. The end of the slot setting operation is performed by the setting end detection unit 24 as described above, and when the slot setting ends, the normal wireless tag detection mode is set.

  In the normal wireless tag detection mode, when the tag management unit 14 causes the wireless signal transmission / reception unit 11 to transmit a question signal in the slot selected by the slot allocation processing unit 21 and receives a response signal from the wireless tag TG, It is determined whether or not the ID of the wireless tag TG is registered in advance, and an unlocking operation or the like is performed.

  With this configuration, it is possible to overlap the slots used so that interference does not occur, and even when many sensors are installed in a wide area, the number of slots used is minimized (slot allocation is efficient). And the response period can be improved by shortening the detection period (period in which the slot makes a round). In addition, by automatically performing such slot setting, new installation work and additional work of the sensor S can be easily performed. During the additional work, the slot number of the entire system is the same as in the new work. May be reset and the slot setting may be performed again, or only the additional sensors and the sensors in the vicinity thereof may determine the slots used by the surrounding sensors and allocate the slots.

  Further, when the setting button of the setting switch 33 is operated to enter the slot setting mode, and in this state, when the start button is operated or when a used slot notification is received from another sensor, slot selection is automatically performed. When the start button of one sensor (S1 in the examples of FIGS. 1 and 2) is operated, the used slots can be automatically and sequentially set to the end like a ripple using that as a trigger.

  Furthermore, the slot selection by the empty slot detection processing unit 211 of the slot allocation processing unit 21 is performed from the slot with higher priority among the empty slots that do not interfere with the adjacent sensors. Can be minimized, and the detection cycle can be shortened to improve the responsiveness.

  When the collision detection unit 221 of the collision detection processing unit 22 detects that the use slot notifications are duplicated, the collision notification transmission processing unit 22 transmits a collision notification, and the collision notification reception processing unit 223 transmits the collision notification. , The retransmission control unit 224 performs re-search for empty slots and retransmission processing for the used slot notification. Thus, in the case of FIG. 1 and FIG. 2, as in the case of the sensors S2 and S3, After the own device (S1) has transmitted the use slot notification, the next or second use slot notification is received, and when it is duplicated, that is, the own device is located at the branch portion of the moving space 1 If the second and second sensors (S2, S3) do not overlap with each other, the detection target areas (A2, A3) do not overlap with each other, and it is not clear that the used slot notifications overlap each other. , Time, it is possible to perform the transmission operation of the search and use slot notifications free slot. Thereby, slot overlap (interference) can be reliably prevented between adjacent sensors (S2, S3).

[Embodiment 2]
FIG. 4 is a timing chart for explaining the operation of the wireless authentication system according to another embodiment of the present invention. As the sensor of the present embodiment, the sensor having the configuration shown in FIG. 1 can be used, and the transmission method of the used slot notification is different only in FIG. 2 and FIG. It should be noted that in the present embodiment, a plurality of (8 in the example of FIG. 4) slots are set within one transmission cycle W1 in the slot setting mode, and the slot allocation processing unit 21 and the slot synchronization unit 23 are set. And the slot allocation processing unit 21 selects the selected slot number. Is transmitted as the use slot notification, the transmission operation from the transmission / reception slot management unit 25 is controlled by the slot synchronization unit 23 and is transmitted at a timing corresponding to the use slot notification. Specifically, each sensor S detects the synchronization of the transmission cycle W1 by the slot synchronization signal detection processing unit 231 by receiving the usage slot notification, and the synchronization timing adjustment processing unit 232 transmits the usage slot notification to be transmitted. The used slot notification from the used slot notification transmission processing unit 212 is transmitted from the transmission / reception slot management unit 25 in the slot corresponding to. On the other hand, when the use slot notification is received by the use slot notification reception processing unit 213 from the transmission / reception slot management unit 25, if the use slot notification can be demodulated (decoded), it is recognized. In the signal detection processing unit 231, the slot No. Query and recognize.

  In the example of FIG. 4, as shown in FIG. 1, the adjacent sensors S <b> 1 and S <b> 4 are at a distance that can receive the used slot notification delicately. 1, the adjacent sensor S3 can receive it, but the adjacent sensor S4 cannot demodulate the slot number. Cannot recognize 1 However, since the carrier has been detected, the slot synchronization signal detection processing unit 231 starts the count operation from the timing t0 when the carrier is no longer detected. After that, the adjacent sensor S3 has a slot No. When the use slot notification is transmitted in step 2, the sensor S4 can also receive it and obtain synchronization. From the demodulated (decoded) use slot notice, the use slot notice received earlier is the slot number. 2 can be determined to have been transmitted, and from the count value until timing t1 that is no longer detected, the slot No. It can be recognized that it was 1. From these recognition results, the empty slot detection processing unit 211 determines the slot number. 1 and no. 2 except for slot no. 3 is determined as the slot of the own device, and a use slot notification is transmitted.

  In this way, when the used slot notification is transmitted, it is not transmitted at an arbitrary timing, but is transmitted at a timing corresponding to the slot, and the used slot notification cannot be demodulated (decoded) due to a low reception level or the like. Even in this case, by determining the use slot notification from the reception timing, the slot setting can be surely performed even when the sensor S is installed with a wider interval.

It is a block diagram which shows the structure of the radio | wireless authentication system which concerns on one Embodiment of this invention. It is a timing chart for explaining slot setting operation of each sensor concerning one embodiment of the present invention. It is a block diagram which shows the example of 1 structure of the sensor which concerns on one Embodiment of this invention. It is a timing chart for demonstrating the slot setting operation | movement of each sensor in the radio | wireless authentication system which concerns on the other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Movement space 2 Host apparatus 11 Radio signal transmission / reception part 12 Slot selection part 13 User interface 14 Tag management part 15 Network interface 21 Slot allocation process part 211 Empty slot detection process part 212 Use slot notification transmission process part 213 Use slot notification reception Processing unit 22 Collision detection processing unit 221 Collision detection unit 222 Collision notification transmission processing unit 223 Collision notification reception processing unit 224 Retransmission control unit 23 Slot synchronization unit 231 Slot synchronization signal detection processing unit 232 Synchronization timing adjustment processing unit 24 Setting end detection unit 25 Transmission / reception slot management unit 31 Status display means 32 Alarm / notification sound generator 33 Setting switches A1, A2, A3, A4,... Detection target areas S1, S2, S3, S4,.

Claims (6)

A plurality of sensors are arranged so that a part of each detection target area overlaps between adjacent sensors along the movement space of the detection target, and the wireless tag carried by the detection target communicates with any one of the sensors. In the wireless authentication system that detects the movement of the detection target by performing
Each sensor is
A wireless communication unit that communicates with the wireless tag using a common wireless communication band, and that can communicate between adjacent sensors;
When a slot to be used by the own device in the wireless communication band is selected and the used slot notification is transmitted from the wireless communication unit, and when the used slot notification is received by the wireless communication unit, the slot selection of the own device is performed. A wireless authentication system including a slot selection unit that is not used. The slot selector
A slot allocation processing unit for selecting a slot to be used by the own device and transmitting a used slot notification;
After transmitting the used slot notification from its own device, upon receiving a collision detection notification, the slot allocation processing unit performs an empty slot re-search and the used slot notification retransmission process, and receives the used slot notification, The wireless authentication system according to claim 1, further comprising: a collision detection processing unit that transmits the collision detection notification when the notification content cannot be reproduced.   A setting button is connected to the slot selection unit, and a slot setting operation is started by operating the setting button. When a start button operation or a use slot notification from another sensor is received, the slot selection is started. The wireless authentication system according to claim 1 or 2, wherein   3. The wireless authentication system according to claim 2, wherein the slot allocation processing unit uses a slot having a higher priority among the empty slots.   When the setting button is operated to start a slot setting operation, the slot selection unit causes the wireless communication unit to increase at least one of transmission power and reception sensitivity compared to when communicating with a wireless tag. The wireless authentication system according to claim 2. The slot selector on the side of transmitting the used slot notification causes the wireless communication unit to perform transmission at a timing corresponding to the used slot notification,
The slot selection unit on the side that has received the use slot notification determines the use slot notification from reception timing of the use slot notification in the wireless communication unit when the use slot notification cannot be demodulated. The radio | wireless authentication system of any one of Claims 1-4.

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