JP2012060657A - Wireless authentication system and sensor thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify slot setting work at initial setting when performing communication with a wireless tag by a time-division multiple access using a common wireless communication band between respective sensors, in a wireless authentication system where a plurality of the sensors are arranged along moving space of a detection object so as to partially overlap the detection object areas between the adjacent sensors to detect movement of the detection object by communication between the wireless tag carried by the detection object and any one of the sensors.SOLUTION: Sensors from an upstream side sensor S1 to a downstream side sensor S4 have sequentially received notifications of slots occupied by the sensors themselves and slots occupied by the receiving adjacent sensors. Of slots, the slot with high priority is selected as a slot for itself from open slots not occupied by directly adjacent sensors, like SL1. Accordingly, the number of slots in use can be restrained to the minimum and a detection period can be shortened, thus achieving high response.

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, the wireless authentication system and the sensor thereof, in particular, a plurality of sensors adjacent to each other along the moving space of the detection target so that the location of the wireless tag and the trajectory passed can be detected. The present invention relates to a configuration in which parts are arranged so as to overlap each other and are 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, in the TDMA-TDD system, it is necessary to perform the pre-slot allocation to avoid using a slot between adjacent sensors, it is possible to determine that assign which slots into which sensor beforehand on paper at the time of new However, there is a problem that it is difficult to determine which slot should be assigned to the sensor to be added when the operation is started once, especially when the sensor is added or moved. In addition, when performing the expansion or relocation, it is necessary to stop the operating system.

  An object of the present invention is to provide a wireless authentication system and its sensor that can easily add a sensor without stopping the system in operation.

Wireless authentication system and sensor of the present invention, a plurality of sensors along the moving space of the detection target, a part of each of the detection target area only between sensor directly adjacent are arranged to overlap each other, the detection In the wireless authentication system and its sensor, the wireless tag carried by the object detects the movement of the detection object by communicating with one of the sensors, and each sensor has a common wireless communication band. Select a wireless communication unit that can be used in time division multiplexing to communicate with the wireless tag and communicate between adjacent sensors, and a slot to be used in the wireless communication band at the time of initial setting. look including a slot selection unit that, the slot selection unit receiving a used slot of its own, the use slots from other sensors adjacent to each other in the wireless communication unit In such a case, together with the use slot notification from other sensors, it is transmitted from the wireless communication unit, and when the use slot notification is received by the wireless communication unit, it is not used by the directly adjacent sensor. Among the empty slots, a slot having a higher priority is selected as a slot of the own device .

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 and its sensor configured to detect movement of a detection target, when performing communication with the wireless tag by time division multiple access (TDMA) using a wireless communication band common to the sensors, using radio communication unit which communicates with the tag to allow communication also between adjacent sensors, during initial setting of the system of new or relocated, select all of which slots Or the slot selection unit for determining provided, when the initial setting mode, the slot selection unit is configured to select the slot to be used by the own apparatus in a wireless communication band, to transmit its use slot notified by the radio communication unit Then, when the use slot of the own device is declared to the remaining sensors and the use slot notification is received by the wireless communication unit, an empty slot not used by the adjacent sensor is selected as the slot of the own device .

Accordingly, in the initial setting mode, the use slots notification, you are possible to automatically set the slots used to not use the same slot between adjacent sensors. As a result, the new sensor installation work can be easily performed.

Also, notifications from other sensors adjacent to the used slot notification are included, and among the empty slots not used by the directly adjacent sensors, a slot with a higher priority is selected as the slot of the own device. For example , if the first slot, the second slot,... Are arranged in descending order of priority, the first slot and the second slot are repeated if the detection target areas are arranged in a straight line, for example. Yuki used Te, lower priority third slot such is used no longer, minimally suppress the number of used slots (the case 2 slots), it is possible to improve the responsiveness by shortening the detection cycle it can.

As described above, the wireless authentication system and the sensor of the present invention can detect the location and the trajectory passed without detecting the detection target such as the user carrying the wireless tag or the product attached with the wireless tag. The wireless tag carried by the detection target is a sensor in which a plurality of sensors are arranged adjacent to each other along the moving space of the detection target so that a part of each detection target area overlaps each other. In the wireless authentication system that detects the movement of the detection target by communicating with the wireless tag, the wireless tag and the wireless tag are connected by time division multiple access (TDMA) using a common wireless communication band between the sensors. when communicating, also so that communication between the sensor adjacent using wireless communication unit for communicating with the wireless tag, upon initialization of the system of new or relocated, The slot selection unit that determines whether to select the slot provided, when it comes to the initial setting mode, the slot selection unit is configured to select the slot to be used by the own apparatus in a wireless communication band, the radio and their use slot notifications Declare the slot used by your device to the remaining sensors, and when the notification of the slot used is received by the wireless communication unit, select a slot that is not used by an adjacent sensor as your own slot. To do.

Therefore, in the initial setting mode, it is possible to automatically set the slots used to not use the same slot between adjacent sensors, the new work of the sensor can be easily performed.

In addition, the slot selection unit includes notifications from other sensors adjacent to the used slot notification, and among the empty slots not used by the directly adjacent sensors, the slot selection unit assigns a slot having a higher priority. By selecting the slot, it is possible to minimize the number of used slots, shorten the detection cycle, and improve the responsiveness.

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 demonstrating operation | movement in the initial setting mode of each sensor which concerns on one Embodiment of this invention. It is a figure for demonstrating the structure of a subslot. It is a timing chart for demonstrating operation | movement in the operation mode of each sensor which concerns on one Embodiment of this invention. It is a timing chart for demonstrating operation | movement in the addition mode of each sensor which concerns on one Embodiment of this invention. It is a timing chart for demonstrating operation | movement in the addition mode of each sensor which concerns on other embodiment of this invention. It is a block diagram which shows the example of 1 structure of the sensor which concerns on one Embodiment of this invention.

  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,... (When collectively referred to as reference symbol S) are arranged along a user's moving space 1 as a detection target, 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 this embodiment, when each sensor S communicates with the wireless tag TG by the TDMA-TDD method using a common wireless communication band, operation of a setting button described later or setting by wireless (remote control) is performed. In response to an instruction or the like, it should be noted that the sensors S communicate with each other automatically, and in the initial setting mode when newly installed, the time slots used for communication by the sensors S can automatically avoid interference. In addition, in the additional mode when the sensor S is added or relocated, an empty slot that does not interfere with the operation while being operated is automatically allocated.

  Each sensor S uses a UHF band 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 additional mode, the reception sensitivity is increased, for example, by a factor of 4, and in FIG. 1, reference numerals A1 ′, A2 ′, A3 ′, A4 ′,. As shown in the figure, even when the reception range is doubled and the sensors S are installed so that the detection target areas A overlap with each other, the slot setting can be reliably performed with sufficient communication quality.

  Specifically, the increase in the receiving sensitivity should be realized by, for example, reducing the directivity of the antenna or switching to a method with low communication speed but high sensitivity in order to increase only the signal level without increasing noise. Can do. 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 the initial setting mode. In the setting, each sensor S is in the initial setting mode by the operation of the setting button or the setting instruction by wireless as described above, and the operator can select any sensor, preferably a sensor located at the end of the sensor array. (S1 in the example of FIGS. 1 and 2) is selected, and the setting operation is started in response to the start button operation or the wireless (remote control) start instruction from the sensor S1. 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 use 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, the used slot notification received from another sensor (S1 in the examples of FIGS. 1 and 2) is also transmitted, so that the history of the slot notification used in the past is sent to the sensor on the terminal side of the sensor array. It is starting to accumulate. Therefore, the sensors S2 and S3 have the slot numbers to be used in their own devices. 2 is a slot No. used in the upper sensor S1. Send 1 together.

  Here, in the example of FIGS. 1 and 2, the sensor S1 is located at the branch 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 (No. 2 + No. 1) is prioritized, and the sensor S2 is given 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. The slot is selected and assigned to the slot to be used by itself, and the use slot notification (No. 3 + No. 1) is transmitted toward another sensor in the next transmission cycle W1.

  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 reception ranges A1 ′, A2 ′; A4 ′ of the signals related to the sensors S1 and S2 do not overlap. Not done. However, from the history shown in the used slot notification from the adjacent sensor S3, the slot No. used by the adjacent sensor S3 is displayed. 3 as well as the slot No. used by the adjacent sensor S1. 1 is also recognized.

  For this reason, it is possible to select an arbitrary slot having a high priority without interfering with the adjacent sensors S1, S2, and S3. For example, in FIG. 2, the slot No. used in the adjacent sensor S3 is simply indicated by a use slot notification indicated by reference numeral SL1. Other than 3, slot No. which is a slot with high priority. 1 or the slot No. used by the adjacent sensor S1. 1 in consideration of the slot No. 1 as in the use slot notification indicated by reference numeral SL2. 4 or the like.

  Here, in the use slot notification SL2, in considering even the adjacent sensor S1, the slot No. 2 is not selected, and the slot number with the lower priority is selected. 4 is selected. This is because the adjacent sensor S1 has a slot No. 1 is selected, the adjacent sensor S3 has its slot No. which is the next rank. This is because it can be estimated that the sensor S3 is not used in relation to another sensor (in this case, S2). With this configuration, even if direct communication is not possible, it is possible to perform slot selection while avoiding slots used by adjacent sensors, and interference can be reliably prevented.

  The number of histories included in the use slot notification includes the number of sensors scheduled to be accommodated in the moving space, the expansion schedule, the number of sensors to be considered, and the required response (the maximum number of slots allowed in one cycle). What is necessary is just to be suitably determined according to etc.

  In this way, the same slot number is set in the sensors S1 and S4 where the detection target areas A1 to A4 do not overlap. 1 can be used, so even if many sensors are installed in a wide area without interference, the number of slots used is minimized (slot allocation is performed efficiently), and the detection cycle It is possible to improve the responsiveness by shortening the (cycle in which the slot makes a round). In addition, considering the selection history included in the used slot notification transmitted from the upper sensor, slot usage by more than 3 sensors can be used for slot selection to avoid the interference. Thus, slot allocation can be automatically performed in consideration of both prevention of interference and improvement of responsiveness.

  On the other hand, the initial setting mode 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.

  When the initial setting mode ends, each sensor S enters the operation mode and communicates with the wireless tag TG. In the operation mode, as shown in FIG. 3, when each sensor S becomes the slot selected as described above within the frame period F of the predetermined number of slots, its own period is determined for the predetermined period of the first half. In response to this, the wireless tag TG in the detection target area A transmits a synchronization signal including the identification information ID, and returns the identification information ID of the received sensor together with the identification information ID of the own device. Each sensor S can recognize the wireless tag TG existing in the detection target area A of the own device. In the example of FIG. 3, the sensor S4 has the slot No. An example in which 4 is selected is shown.

  When the number of RFID tags TG accommodated in each detection target area A is large, each slot is set as a subframe, and a frame synchronization signal is transmitted in the first half of the subframe as shown in FIG. Slots TG1, TG2,... May be divided into empty slots. First, the wireless tag that newly enters the detection target area A transmits a transmission request including its own identification information ID in the empty slot, and each sensor S should respond with a frame synchronization signal of the next frame. The identification information ID of the tag and the slot number. And the designated sensor may perform authentication by performing a response in the designated slot.

  In the operation mode, it should be noted that, as shown in FIG. 4, each sensor S receives the use slot notification in its own device and the use slot notification from the adjacent sensor in the initial setting mode, as shown in FIG. That is, the information including the information on the slot used by the adjacent sensor is transmitted. Therefore, when a sensor is added to a lower level of an arbitrary sensor for expansion or relocation, when an operator enters an additional mode by operating an additional button of the sensor to be added or an instruction for wireless addition, the sensor is By increasing the reception sensitivity and receiving a synchronization signal transmitted by another sensor in operation over at least one frame period F, an empty slot can be detected, and from the synchronization signal, It is also possible to grasp the status of slots used around. The sensor to be added refers to the status of the slot used, determines the slot with the highest priority among the empty slots as the slot to be used by itself, and starts operation from the next frame. Included in the synchronization signal from the own device, the used slot notification is transmitted to the adjacent sensor.

  A sensor to which a sensor is added below its own device is in an add mode by operating the add button or an instruction to add wirelessly, etc., to increase the reception sensitivity. Use slot information in the machine is updated. Thus, the sensor to be added and the sensor adjacent thereto can automatically enter the operation after finishing the addition mode.

  FIG. 5 is a timing chart for explaining the operation in such an additional mode. This example shows a case where the sensor S4 in FIG. 1 is added. Therefore, the existing sensors S1 to S3 transmit a synchronization signal as shown in FIG. 4 at the slot timing of the own device in each frame F1, F2,... And wait for a response from the wireless tag TG. .

  The added sensor S4 receives the synchronization signal of the adjacent sensor for at least one frame period F to determine the total number of slots, and in frame F1, the synchronization signal from the sensor S3 that will be adjacent to the own device. , The sensor S4 receives the slot number in the adjacent sensor S3 with reference to the use slot information included in the synchronization signal as described in FIG. 3 is in use, and in the adjacent sensors S1 and S2, the slot No. 1, No. 1 2 recognizes that it is in use. 4 is selected, and transmission of a synchronization signal is started in the next frame F2. The determination of the one-frame period F is based on the slot number of the received synchronization signal. (3 in this case) is stored, and the same slot number is stored again. The total number of slots can be obtained by dividing the count value by a fixed one-slot period W0.

  Here, the sensor S4 added as described above increases the reception sensitivity when it is in the addition mode. However, if the sensor to be referred to for slot selection is about the next adjacent sensor, the reception sensitivity is increased. If it is possible to receive a synchronization signal directly from the next adjacent sensor by the up of the above, the use slot information is not necessarily required. However, the use slot information is preferable because it is possible to accurately grasp the status of the slots used by the sensors in the desired range regardless of the communication status between the sensors S.

  Preferably, the use slot information included in the synchronization signal is transmitted only when there is a request from the added sensor. Specifically, as shown in FIG. 6, the sensor S4 that has entered the addition mode by operating the addition button or the like is synchronized with other sensors in operation for at least one frame period as described above. A signal is received to detect an empty slot, and a request for used slot information is transmitted in a response period of the wireless tag TG to the synchronization signal of the sensor S3 to which the own device should be subordinate. The existing (in operation) sensor S3 that has received this returns the use slot information in its own device during the synchronization signal in the next frame, and the sensor to be added that has received this returns the use slot information. Referring to it, the slot with the highest priority among the empty slots is determined as the slot to be used by the own device, the operation is started from the next frame, and it is included in the synchronization signal from the own device and the used slot notification is adjacent. Send to the sensor.

  FIG. 7 is a block diagram showing a configuration example of the sensor S that realizes the function shown in FIG. 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.

  As shown in FIG. 2, the slot selection unit 12 selects a slot to be used by the own device, transmits a used slot notification, and transmits the used slot notification from the own device. When the detection notification is received, the slot allocation processing unit 21 retransmits the use slot notification. When the use slot notification is received and cannot be reproduced, a collision detection processing unit 22 that transmits the collision detection notification, A slot synchronization unit 23 that synchronizes communication, a setting end detection unit 24 that determines the end of the slot setting operation, a transmission / reception slot management unit 25 that controls the entire slot selection unit 12, and a sensor as shown in FIG. And a sensor addition processing unit 26 that realizes the addition processing.

  The user interface 13 displays, for example, that it is an operation mode in which a normal detection operation of the RFID tag TG is performed, is the initial setting mode or the addition mode, and whether these setting modes have been normally completed. Status display means 31 for notifying the user of a malfunction or the like by a lamp display or the like, and when an abnormality or suspicious wireless tag is detected, an alarm is issued or the wireless tag TG can be recognized normally and the door is unlocked, etc. The alarm / notification sound generating device 32 such as a buzzer for notifying that the operation is performed, and the setting switch 33 such as the setting button, start button, and additional button are configured.

  When the initial 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. The slot number received by the used slot notification reception processing unit 213. The necessary portion of the information 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 radio 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 in the setting end detection unit 24 as described above, and when the initial setting mode or the addition mode ends, the operation mode for detecting a normal wireless tag is set.

  On the other hand, when the sensor addition operation is started by operating the addition button of the setting switch 33, the empty slot detection unit 265 of the sensor addition processing unit 26 determines the one frame period F, and the sensor addition request transmission processing unit 261 transmits and receives. Through the slot management unit 25 and the wireless signal transmission / reception unit 11, a request for used slot information is transmitted to other sensors as described above. The sensor addition request reception processing unit 262 of the existing (in operation) sensor that has received this via the wireless signal transmission / reception unit 11 and the transmission / reception slot management unit 25, uses the used slot notification reception processing unit 213 of the slot allocation processing unit 21. Refer to the slot no. Slot No. being used by surrounding sensors. In addition, the used slot notification transmission processing unit 263 is transmitted to other sensors as a synchronization signal.

  When the used slot notification reception processing unit 264 receives the used slot information from the synchronization signal, the empty slot detecting unit 265 obtains empty slots by excluding the used slots from all the slots, and the priority order among them is determined. The slot having the highest slot is determined as the slot used by the own apparatus, and is transmitted to the slot used transmission transmission processing unit 263. When this is received by the use slot notification reception processing unit 264, the use slot information in the use slot notification reception processing unit 213 is updated.

  In an operation mode in which normal wireless tag detection is performed, the tag management unit 14 includes a question signal including its own ID in the synchronization signal of the slot selected by the slot allocation processing unit 21 in the wireless signal transmission / reception unit 11. When the response signal is received 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.

  By configuring in this way, it is possible to overlap the slots used in any desired range so that interference does not occur, and even when many sensors are installed in a wide area, the number of slots used is minimized. Responsiveness can be improved by suppressing (slot allocation efficiently) and shortening the detection cycle (cycle in which the slot makes a round). In addition, the initial setting or additional setting of such a slot is automatically performed by searching for an empty slot, whereby the new installation work or additional work of the sensor S can be easily performed. Furthermore, the sensor can be added while the existing sensor is in operation. If there are a large number of additional sensors or relocated sensors, the slot number of the entire system is the same as in the new installation. May be reset and the slot setting may be performed again.

  In addition, the slot selection by the empty slot detection processing units 211 and 265 is performed from the highest priority slot among the empty slots that do not interfere with the adjacent sensors, so the number of slots used is minimized. The detection cycle can be shortened to improve the responsiveness.

  Furthermore, when the own device is added to the system in operation, the used slot notification receiving processing unit 264 receives the synchronization signal transmitted by the used slot notification processing unit 263 of the adjacent sensor, and is displayed in the synchronization signal. Since the slot information used by the adjacent sensor is referred to the selection of the empty slot by the empty slot detection processing unit 265, not only the slot used by the adjacent sensor but also the direct synchronization signal is used. Even the slots used by the next adjacent sensor that cannot be received can be recognized and direct synchronization signals cannot be received, but interference with the next adjacent sensor that may overlap the detection target area is also considered Thus, further interference can be prevented.

  Further, the used slot notification transmission processing unit 263 of the sensor in operation does not always transmit the usage slot information of the adjacent sensor, but is transmitted from the sensor addition request transmission processing unit 261 of the added sensor. Only when the request for use slot information is received by the sensor addition request reception processing unit 262 is rare, by transmitting the synchronization signal including use slot information, communication overhead can be reduced.

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 26 Sensor addition processing unit 261 Sensor addition request transmission processing unit 262 Sensor addition request reception processing unit 263 Used slot notification transmission processing unit 264 Used slot notification reception processing unit 265 Empty slot detection processing unit 31 Status display Stage 32 alarm / notification sound generator 33 sets switch A1, A2, A3, A4, ··· detection target area S1, S2, S3, S4, ··· sensor TG RFID

Claims (2)

A plurality of sensors are arranged along the movement space of the detection target so that a part of each detection target area overlaps only between directly adjacent sensors, and the wireless tag carried by the detection target is any In the wireless authentication system that detects the movement of the detection object by communicating with the sensor,
Each sensor is
A wireless communication unit capable of performing communication with the wireless tag using a common wireless communication band by time division multiplexing, and capable of performing communication between adjacent sensors;
In the wireless communication band during initialization and a slot selection unit for selecting a slot to be used by the own apparatus seen including,
When the slot selection unit receives a use slot of its own device and a use slot from another sensor adjacent to the wireless communication unit, the wireless communication unit combines the use slot notification from the other sensor. When the use slot notification is received by the wireless communication unit, a slot having a higher priority is selected as a slot of the own device among empty slots not used by the directly adjacent sensor. A featured wireless authentication system. More along the moving space of the detection target, direct a portion of the adjacent respective detection target area with each other which are arranged to overlap each other, communicating with one radio tag any to be carried to the detection target In the sensor of the wireless authentication system that detects the movement of the detection target by moving,
A wireless communication unit capable of performing communication with the wireless tag using a common wireless communication band by time division multiplexing, and capable of performing communication between adjacent sensors;
In the wireless communication band during initialization and a slot selection unit for selecting a slot to be used by the own apparatus seen including,
When the slot selection unit receives a use slot of its own device and a use slot from another sensor adjacent to the wireless communication unit, the wireless communication unit combines the use slot notification from the other sensor. When the use slot notification is received by the wireless communication unit, a slot having a higher priority is selected as a slot of the own device among empty slots not used by the directly adjacent sensor. A featured sensor.

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