Communication system and communication method

Abstract

To provide a communication system, a master station, a slave station, a communication method, and a communication program, capable of associating the master station and a plurality of slave stations with one another with a simple configuration.SOLUTION: A communication system 10 comprises: a first slave station that transmits a search signal for identifying a first master station corresponding to the first slave station: a plurality of master stations, each of which when the search signal is received, transmits a report including identification information on the master station, identification information on the first slave station, and signal information on the search signal to a management server; and the management server that on the basis of a plurality of reports received from the respective master stations, determines the first master station corresponding to the first slave station from the plurality of master stations and associates the first slave station and the first master station with each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a communication system, a master station, a slave station, a communication method, and a communication program. [Background technology]

[0002] A conventional communication method known as TDMA (Time Division Multiple Access) is one in which one master station (also called a controller or host) occupies one channel and communicates with multiple slave stations (also called slaves) assigned to the master station in turn in a time-division manner. Each slave station is assigned a certain period of time immediately after receiving communication (transmission data) from the master station during which it can communicate with the host. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-129235 Summary of the Invention [Problem to be solved by the invention]

[0004] In factories, warehouses, and the like, workers perform picking work, picking items stored on storage shelves. Conventionally, picking systems have been introduced to streamline the picking work. In the picking system, a work area is equipped with multiple storage shelves, slave stations (tags with communication capabilities) installed on each shelf, and a master station (controller) that controls the multiple tags. The controller sends a command (which may include a lighting command) to the tag on the shelf where the item to be picked is stored, lighting up a lamp (LED) mounted on the tag. The worker picks the desired item from the storage shelf with the lit lamp button.

[0005] In the picking system, when constructing a large number of star-topology networks consisting of a master station and multiple slave stations, it is necessary to associate each of the multiple slave stations with a specific master station with which communication is stable. However, with conventional technology, it is not easy to associate a master station with multiple slave stations, as the slave stations must perform many procedures.

[0006] An object of the present invention is to provide a communication system, a master station, a slave station, a communication method, and a communication program that are capable of associating a master station and a plurality of slave stations with each other using a simple configuration. [Means for solving the problem]

[0007] A communication system according to an embodiment of the present invention includes a management server, multiple master stations, and multiple slave stations. A first slave station transmits a search signal to identify a first master station corresponding to the first slave station. Upon receiving the search signal, each of the multiple master stations transmits a report to the management server, the report including identification information of the master station, identification information of the first slave station, and signal information related to the search signal. The management server determines the first master station corresponding to the first slave station from among the multiple master stations based on the reports received from each of the multiple master stations, and associates the first slave station with the first master station.

[0008] A master station according to an embodiment of the present invention is a master station that communicates with a management server and multiple slave stations, and when it receives a search signal transmitted from a first slave station for identifying the master station corresponding to the first slave station, it transmits a report to the management server that includes identification information of the master station, identification information of the first slave station, and signal information regarding the search signal.

[0009] A slave station according to an embodiment of the present invention is a slave station that communicates with a management server and multiple master stations, and when it receives a search instruction, it transmits a search signal to the multiple master stations to identify the master station corresponding to the slave station using a channel different from the channel on which the beacon transmitted from the master station is received.

[0010] A communication method according to an embodiment of the present invention is a communication method in which a management server, multiple master stations, and multiple slave stations communicate wirelessly, and the method includes the following steps performed by one or more processors: transmitting a search signal from a first slave station to identify the first master station corresponding to the first slave station; transmitting a report to the management server, when each of the multiple master stations receives the search signal, the report including identification information of the master station, identification information of the first slave station, and signal information related to the search signal; and determining, in the management server, the first master station corresponding to the first slave station from among the multiple master stations based on the multiple reports received from each of the multiple master stations, and associating the first slave station with the first master station.

[0011] A communication program according to an embodiment of the present invention is a communication program for wireless communication between a management server, multiple master stations, and multiple slave stations, and causes one or more processors to execute the following steps: a step of transmitting a search signal from a first slave station to identify the first master station corresponding to the first slave station; a step of transmitting a report to the management server, when each of the multiple master stations receives the search signal, the report including identification information of the master station, identification information of the first slave station, and signal information related to the search signal; and a step of determining, in the management server, the first master station corresponding to the first slave station from among the multiple master stations based on the multiple reports received from each of the multiple master stations, and associating the first slave station with the first master station. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a communication system, a master station, a slave station, a communication method, and a communication program that are capable of associating a master station and a plurality of slave stations with each other using a simple configuration. [Brief explanation of the drawings]

[0013] [Figure 1]FIG. 1 is a functional block diagram showing a schematic configuration of a communication system according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an external view of the storage shelf according to the embodiment of the present invention. [Figure 3A] FIG. 3A is a diagram showing the configuration of a tag installed on a storage shelf according to an embodiment of the present invention. [Figure 3B] FIG. 3B is a bottom view of a tag according to an embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing an example of tag information stored in the storage unit of the communication system according to the embodiment of the present invention. [Figure 5] FIG. 5 is a diagram showing an example of related information stored in the storage unit of the communication system according to the embodiment of the present invention. [Figure 6] FIG. 6 is a diagram showing the correspondence between the controller and the tag according to the embodiment of the present invention. [Figure 7] FIG. 7 is a diagram showing an example of time segments to which controllers are assigned according to an embodiment of the present invention. [Figure 8] FIG. 8 is a diagram showing a specific example of a communication method according to an embodiment of the present invention. [Figure 9] FIG. 9 is a diagram showing a specific example of a communication method according to an embodiment of the present invention. [Figure 10] FIG. 10 is a flowchart illustrating an example of a procedure of a communication process executed in the communication system according to the first embodiment of the present invention. [Figure 11] FIG. 11 is a diagram showing the correspondence between the controller and the communication area according to the embodiment of the present invention. [Figure 12] FIG. 12 is a diagram showing how each of a plurality of controllers according to an embodiment of the present invention is assigned to a channel and a time segment. [Figure 13] FIG. 13 is a functional block diagram showing a schematic configuration of a communication system according to the second embodiment of the present invention. [Figure 14] FIG. 14 is a diagram showing a specific example of the association process in the communication system according to the second embodiment of the present invention. [Figure 15] FIG. 15 shows an example of a procedure for processing to associate a management server, a plurality of controllers, and a target tag in a communication system according to the second embodiment of the present invention. [Figure 16] FIG. 16 is a flowchart illustrating an example of the procedure of the association process executed in the target tag according to the second embodiment of the present invention. [Figure 17] FIG. 17 is a flowchart illustrating an example of the procedure of the association process executed by the controller according to the second embodiment of the present invention. [Figure 18] FIG. 18 is a flowchart illustrating an example of the procedure of the association process executed in the management server according to the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following embodiments are examples of specific embodiments of the present invention and do not limit the technical scope of the present invention.

[0015] [Embodiment 1] FIG. 1 is a functional block diagram showing a schematic configuration of a communication system 10 according to a first embodiment of the present invention.

[0016] The communication system 10 includes a management server 1, a controller 2, and a tag Tg. The communication system 10 is installed, for example, in a work site (such as a factory or warehouse) where a worker picks a desired item from a storage shelf 3 (see FIG. 2) that stores the item. The item is not particularly limited and includes items from various fields such as parts, retail goods, medicines, books, documents, and miscellaneous goods. In this embodiment, an example of the item is a part used in the assembly work of a predetermined product (such as a vehicle or an electrical appliance). That is, the communication system 10 in this embodiment is installed in a facility F1 (such as a factory) where a worker picks a desired part from a storage shelf 3 that stores the part.

[0017] The management server 1 and the controller 2 are connected to each other via a network N1. The network N1 is a communication network such as the Internet, a LAN, a WAN, or a public telephone line. The controller 2 and the tag Tg are connected via this radio wave communication method. The tag Tg is installed on each storage shelf 31 of the storage shelf 3 (see FIG. 2). As shown in FIG. 3A, the tag Tg includes a display unit (LCD) that displays the part name, a lamp button B1 that lights up, blinks, and turns off in multiple colors, and a communication unit (not shown) that communicates with the controller 2. The lamp button B1 also functions as a button as a user interface. The tag Tg can display specific information on the display unit and turn on or off the lamp button B1 in accordance with commands (transmitted data) from the controller 2. For example, a worker picks a part from the storage shelf 31 on which the tag Tg with the lamp button B1 lit is installed. The tag Tg notifies the controller 2 that the lamp button B1 has been pressed via this communication method, and the controller 2 notifies the management server 1. If the tag Tg corresponds to the correct part, the management server 1 uses this communication method to notify the tag Tg corresponding to the next part to be picked via the controller 2 of a signal that causes the lamp button B1 to blink at a specified interval. Figure 3A shows the tag 1 in a lit state. The management server 1 controls each controller 2 collectively, and based on the information about the part to be picked, outputs a transmission instruction to a specified controller 2 to send data (such as an instruction to light up the tag Tg).

[0018] A plurality of storage shelves 3 are arranged within facility F1. A plurality of controllers 2 are installed in a distributed manner within facility F1, and the plurality of controllers 2 communicate with tags Tg on the plurality of storage shelves 3 arranged within facility F1. In this manner, communication system 10 establishes a picking system for facility F1 by controlling a plurality of tags Tg arranged within facility F1 using a plurality of controllers 2. Specifically, communication system 10 is a system that manages radio wave communication between a plurality of controllers 2 and a plurality of tags Tg so that it is performed at a predetermined cycle.

[0019] The management server 1 functions as an arbitration station that manages and controls the controller 2, the controller 2 functions as a host device, and the tag Tg functions as a slave device. The controller 2 is an example of a master station of the present invention, and the tag Tg is an example of a slave station of the present invention.

[0020] [Management Server 1] 1, the management server 1 includes a control unit 11, a storage unit 12, an operation display unit 13, and a communication unit 14. The management server 1 may be an information processing device such as a personal computer. The management server 1 may also be configured as a cloud server.

[0021] The communication unit 14 connects the management server 1 to the network N1 by wire or wirelessly, and executes data communication with the controller 2 via the network N1 in accordance with a predetermined communication protocol.

[0022] The operation display unit 13 is a user interface that includes a display unit such as a liquid crystal display or an organic EL display that displays various information, and an operation unit such as a touch panel, a mouse, or a keyboard that accepts operations.

[0023] The storage unit 12 is a non-volatile storage unit such as a hard disk drive (HDD), a solid state drive (SSD), or a flash memory that stores various types of information. The storage unit 12 stores data such as tag information D1 and related information D2.

[0024] FIG. 4 is a diagram showing an example of tag information D1. Information about all tags Tg placed in facility F1 is registered in tag information D1. Specifically, tag information D1 includes information such as tag ID, location information, and part name. The tag ID is identification information of tag Tg. The location information is location information about the location where tag Tg is installed, such as the location of storage shelf 3, the shelf number of storage shelf 3 (storage shelf 31), and coordinates on a map of facility F1. The part name is the name of the part stored in storage shelf 31 where tag Tg is installed.

[0025] The tag information D1 is registered by, for example, the manager of the facility F1. The tag information D1 may also be stored in a server different from the management server 1.

[0026] FIG. 5 is a diagram showing an example of the related information D2. The related information D2 is information for identifying the tag Tg associated with each of the multiple controllers 2. Specifically, the related information D2 includes information such as a controller ID and a tag ID. The controller ID is identification information for the controller 2, and the tag ID is identification information for the tag Tg. In reality, each controller 2 is associated with a tag Tg that provides the most stable communication, so the IDs of the tag Tg are random and have no regularity.

[0027] As shown in FIG. 6, one controller 2 is associated with multiple tags Tg. Each controller 2 can communicate with multiple tags Tg, and each tag Tg can communicate with one controller 2. For example, controller A can communicate with tags Tg within communication area AR1, and controller B can communicate with tags Tg within communication area AR2. In practice, to ensure sufficient communication stability, one tag Tg is often located within the communication areas AR of multiple controllers 2, as shown in FIG. 11. Each tag Tg is associated with the controller 2 with the most stable communication among the multiple controllers 2, but as shown in FIG. 11, this area is subject to radio wave interference among the multiple controllers 2. In this embodiment, five controllers 2 (controllers A to E) cover the entire work area of ​​facility F1 and are capable of communicating with all tags Tg within facility F1. The associated information D2 is registered by processing (described below) by the control unit 11.

[0028] The storage unit 12 may also store picking information including the order in which parts are to be picked. The picking information is registered by associating each part to be picked with information such as tag ID, location information, and picking status. The management server 1 registers information about the parts to be picked in the picking information based on a picking instruction. The management server 1 may obtain the picking instruction from a server that manages the manufacturing process of the product, or may generate the picking information based on the manufacturing process stored in the storage unit 12.

[0029] The storage unit 12 also stores control programs such as a communication program for causing the control unit 11 to execute a communication process (see FIG. 10) described below. For example, the communication program is non-temporarily recorded on a computer-readable recording medium such as a CD or DVD, and is read by a reading device (not shown) such as a CD drive or DVD drive electrically connected to the management server 1 and stored in the storage unit 12.

[0030] The control unit 11 has control devices such as a CPU. The CPU is a processor that executes various types of arithmetic processing. The control unit 11 controls the management server 1 by executing various control programs pre-stored in the storage unit 12 using the CPU.

[0031] Specifically, the control unit 11 includes various processing units such as an associated processing unit 111, an allocation processing unit 112, and a communication processing unit 113. The control unit 11 functions as the various processing units by executing various processes in accordance with the communication program using the CPU. Some or all of the processing units included in the control unit 11 may be configured with electronic circuits. The communication program may be a program for causing multiple processors to function as the various processing units.

[0032] The association processing unit 111 associates each of the plurality of tags Tg with one of the plurality of controllers 2.

[0033] 5, the association processing unit 111 associates multiple tags Tg with tag IDs "tg0001 to tg0100" located in communication area AR1 with a controller A with a controller ID "c0001" located in communication area AR1. The association processing unit 111 also associates multiple tags Tg with tag IDs "tg0101 to tg0200" located in communication area AR2 with a controller B with a controller ID "c0002" located in communication area AR2. The association processing unit 111 also associates multiple tags Tg with tag IDs "tg0201 to tg0300" located in communication area AR3 with a controller C with a controller ID "c0003" located in communication area AR3. Furthermore, the association processing unit 111 associates multiple tags Tg with tag IDs "tg0301 to tg0400" located in communication area AR4 with a controller D with a controller ID "c0004" located in communication area AR4. Furthermore, the association processing unit 111 associates multiple tags Tg with tag IDs "tg0401 to tg0500" located in communication area AR5 with a controller E with a controller ID "c0005" located in communication area AR5.

[0034] The above association is the result of associating each tag Tg with the controller 2 with which communication is most stable, and then assigning an appropriate number. In the present invention, each of the multiple slave stations may be associated with one of the multiple master stations in advance. Another method (association process) for associating each of the multiple slave stations with one of the multiple master stations will be described in embodiment 2.

[0035] The related processing unit 111 registers information on the controller 2 and the tag Tg that are associated with each other in the related information D2 (see FIG. 5).

[0036] The allocation processing unit 112 allocates each of the multiple controllers 2 to a plurality of time segments (time slots) obtained by time-dividing a predetermined period in a predetermined channel. For example, as shown in FIG. 7, if the period is "C1," the period C1 is divided into a plurality of time segments. Here, the period C1 is divided into five time segments t1 to t5. Also, it is assumed that one predetermined channel CH1 is used. To the channel CH1, a number of controllers 2 capable of communicating with a plurality of tags Tg in the predetermined period are allocated. For example, the allocation processing unit 112 allocates controller A to the first time segment t1, controller B to the second time segment t2, controller C to the third time segment t3, controller D to the fourth time segment t4, and controller E to the fifth time segment t5.

[0037] The allocation processing unit 112 allocates the controllers A to E to the time segments t1 to t5 in order for each cycle C1.

[0038] The communication processing unit 113 causes the controller 2 to communicate with the multiple tags Tg associated with the controller 2 by the association processing unit 111 during each of a plurality of time segments. A specific example of the communication method will be described with reference to FIG. 8.

[0039] 8, in channel CH1, the period C1 is set to "200 ms" and the time width of each of the time segments t1 to t5 is set to "40 ms." The communication processing unit 113 outputs a transmission instruction for transmission data to the controller A in the first time segment t1, which is the beginning of the period C1. The transmission data is, for example, a beacon.

[0040] Here, as shown in FIG. 9, the transmission data includes information on a command (command information) that causes a tag Tg to execute a predetermined process, and identification information (destination information) that identifies the tag Tg that is to execute the command. Specifically, the transmission data includes destination information for each of a predetermined number of tags Tg, and command information that causes each of the predetermined number of tags Tg to execute a predetermined command. For example, FIG. 9 shows an example of transmission data transmitted by controller A. Of the multiple tags Tg (see FIG. 5) associated with controller A, the communication processing unit 113 identifies five tags Tg (see FIG. 4) associated with the five parts to be picked, and outputs to controller A a transmission instruction for transmission data that includes the identified five tags 1 to 5 as destinations.

[0041] That is, the communication processing unit 113 causes the controller A to transmit transmission data to a predetermined number of tags Tg among the multiple tags Tg associated with the controller A. Furthermore, the controller A transmits the transmission data to a predetermined number of tags Tg that can communicate with the controller A within a time segment.

[0042] When controller A receives the transmission instruction from management server 1, it transmits the transmission data (see FIG. 9) to all tags Tg (see FIG. 5) associated with controller A in the first time segment t1 (see FIG. 8).

[0043] When each tag Tg associated with the controller A receives the transmission data, it checks the destination included in the transmission data and executes a predetermined process if a command addressed to itself is included. For example, when tag 1 receives the transmission data including a command addressed to itself to turn on lamp button B1 (see FIG. 3A), it turns on lamp button B1 (see FIG. 3A). Furthermore, when tag 1 executes the command, it transmits a response (acknowledgement response) to the controller A. Similarly, when each of tags 2 to 5 receives the transmission data and finds that it contains a command addressed to itself, it turns on lamp button B1 (see FIG. 3A) and transmits a response (acknowledgement response) to the controller A. The controller A receives responses from each of tags 1 to 5 (see FIG. 9). At this time, tags 1 to 5 transmit appropriately at a timing that will prevent collisions between each other, depending on the position of the command addressed to them in the transmission data. In this embodiment, each tag Tg transmits an acknowledgment response of the same size in the order in which the command was received, and by leaving a time interval that takes into account the time required for each acknowledgment response transmission and a predetermined margin, collisions between the acknowledgment response signals are prevented.

[0044] Furthermore, in this embodiment, the tag data reception period R1 (FIG. 9) is designed to remain after all five tags have sent their confirmation responses within the time segment, and the tag Tg whose lamp button function is pressed will transmit using the CSMA / CA method during the subsequent tag data reception period R1. The tag data reception period R1 shown in FIG. 9 is the uplink period from the tag Tg to the controller 2 using the CSMA / CA method.

[0045] The confirmation response is not limited to button press information, but may be the operation content of another user interface if the tag Tg has a sensor function. Also, if the tag Tg has a sensor function, the tag Tg may spontaneously transmit the confirmation response when the measurement value satisfies a predetermined condition.

[0046] Controller A transmits the transmission data to tags 1 to 5 in the first time segment t1 (40 ms) of cycle C1 (200 ms), and when execution of the commands of tags 1 to 5 is completed, communication processing unit 113 outputs a transmission instruction for the transmission data to controller B in the next second time segment t2 of cycle C1 (200 ms) (see FIG. 8). The transmission data includes the destinations of tags 6 to 10 and a command.

[0047] When each tag Tg associated with the controller B receives the transmission data, it checks the destination included in the transmission data and executes a predetermined process if a command addressed to itself is included. For example, when the tag 6 receives the transmission data including a command addressed to itself to turn on the lamp button B1 (see FIG. 3A), it turns on the lamp button B1 (see FIG. 3A) because the command addressed to itself is included. Furthermore, when the tag 6 executes the command, it sends a response (acknowledgement) to the controller B. Similarly, when each of the tags 7 to 10 receives the transmission data, it turns on the lamp button B1 (see FIG. 3A) because the command addressed to itself is included, and sends a response (acknowledgement) to the controller B. The controller B receives the responses from each of the tags 6 to 10.

[0048] Controller B transmits the transmission data to tags 6 to 10 in the second time segment t2 (40 ms) of cycle C1 (200 ms), and when execution of the commands of tags 6 to 10 is completed, communication processing unit 113 outputs a transmission instruction for the transmission data to controller C in the next third time segment t3 of cycle C1 (200 ms). The transmission data includes the destinations and commands of tags 11 to 15 (see FIG. 8).

[0049] When each tag Tg associated with the controller C receives the transmission data, it checks the destination included in the transmission data and executes a predetermined process if a command addressed to itself is included. For example, when the tag 11 receives the transmission data including a command addressed to itself to turn on the lamp button B1 (see FIG. 3A), the tag 11 turns on the lamp button B1 (see FIG. 3A) since the command addressed to itself is included. Furthermore, when the tag 11 executes the command, it transmits a response (acknowledgement) to the controller C. Similarly, when each of the tags 12 to 15 receives the transmission data, the tag 11 turns on the lamp button B1 (see FIG. 3A) since the command addressed to itself is included, and transmits a response (acknowledgement) to the controller C. The controller C receives the responses from each of the tags 11 to 15 (see FIG. 8).

[0050] Controller C transmits the transmission data to tags 11-15 in the third time segment t3 (40 ms) of cycle C1 (200 ms), and when execution of the commands of tags 11-15 is completed, communication processing unit 113 outputs a transmission instruction for the transmission data to controller D in the next fourth time segment t4 of cycle C1 (200 ms). The transmission data includes the destinations of tags 16-20 and a command.

[0051] When each tag Tg associated with the controller D receives the transmission data, it checks the destination included in the transmission data and executes a predetermined process if a command addressed to itself is included. For example, when the tag 16 receives the transmission data including a command addressed to itself to turn on the lamp button B1 (see FIG. 3A), the tag 16 turns on the lamp button B1 (see FIG. 3A) since the command addressed to itself is included. Furthermore, when the tag 16 executes the command, it transmits a response (acknowledgement) to the controller D. Similarly, when each of the tags 17 to 20 receives the transmission data, the tag 16 turns on the lamp button B1 (see FIG. 3A) since the command addressed to itself is included, and transmits a response (acknowledgement) to the controller D. The controller D receives the responses from each of the tags 16 to 20 (see FIG. 8).

[0052] Controller D transmits the transmission data to tags 16-20 in the fourth time segment t4 (40 ms) of cycle C1 (200 ms), and when execution of the commands of tags 16-20 is completed, communication processing unit 113 outputs a transmission instruction for the transmission data to controller E in the next fifth time segment t5 of cycle C1 (200 ms). The transmission data includes the destinations of tags 21-25 and a command.

[0053] When each tag Tg associated with the controller E receives the transmission data, it checks the destination included in the transmission data and executes a predetermined process if a command addressed to itself is included. For example, when the tag 21 receives the transmission data including a command addressed to itself to turn on the lamp button B1 (see FIG. 3A), it turns on the lamp button B1 (see FIG. 3A) since the command addressed to itself is included. Furthermore, when the tag 21 executes the command, it sends a response (acknowledgement) to the controller E. Similarly, when each of the tags 22 to 25 receives the transmission data, it turns on the lamp button B1 (see FIG. 3A) since the command addressed to itself is included, and sends a response (acknowledgement) to the controller E. The controller E receives the responses from each of the tags 21 to 25 (see FIG. 8).

[0054] Controller E transmits the transmission data to tags 21 to 25 in the fifth time segment t5 (40 ms) of cycle C1 (200 ms), and when execution of the commands of tags 21 to 25 is completed, communication processing unit 113 again outputs a transmission instruction for transmission data to controller A in the first time segment t1 at the beginning of the next cycle C1 (200 ms). The transmission data includes the destinations of tags 1 to 5 and a command.

[0055] When each tag Tg associated with the controller A receives the transmission data, it checks the destination included in the transmission data and executes a predetermined process if a command addressed to itself is included. For example, when tag 1 receives the transmission data including a command addressed to itself to turn on lamp button B1 (see FIG. 3A), it turns on lamp button B1 (see FIG. 3A) because the command addressed to itself is included. Furthermore, when tag 1 executes the command, it sends a response (acknowledgement) to the controller A. Similarly, when each of tags 2 to 5 receives the transmission data, it turns on lamp button B1 (see FIG. 3A) because the command addressed to itself is included, and sends a response (acknowledgement) to the controller A. The controller A receives the responses from each of tags 1 to 5 (see FIG. 8).

[0056] As described above, the communication processing unit 113 causes the controller 2 to communicate with the multiple tags Tg associated with the controller 2 within each of the multiple time segments. The communication processing unit 113 also outputs a transmission instruction for the transmission data to each of the multiple controllers 2 in the order of the time segments. As a result, for example, each of the controllers A to E communicates with the tag Tg controlled by each controller in the order of time segments t1 to t5.

[0057] For example, after controller A transmits the transmission data to five tags 1 to 5 among the multiple tags Tg associated with controller A in a first time segment t1, controller B transmits the transmission data to five tags 6 to 10 among the multiple tags Tg associated with controller B in a second time segment t2 following the first time segment t1.

[0058] Furthermore, controller A transmits the transmission data to tags 1 to 5 in the first time segment t1, and after controller A receives responses from tags 1 to 5, controller B transmits the transmission data to tags 6 to 10 in the second time segment t2.

[0059] Here, the control unit 11 executes a process to synchronize (time synchronization) the management server 1 and each controller. Furthermore, each controller 2 executes a process to synchronize (time synchronization) with each corresponding tag Tg. As a result, each controller 2 transmits transmission data to the tag Tg at a predetermined cycle (for example, 200 ms), and each tag Tg receives the transmission data at a predetermined cycle (for example, 200 ms). For example, each tag Tg starts to start up in accordance with the reception time of the transmission data, and starts receiving the transmission data at that reception time. Furthermore, each tag Tg completes the reception process at the time when transmission of the transmission data is completed in the controller 2, and performs time synchronization after the reception process is completed. Each tag Tg sets a timer and waits (power saves) until the next reception time of the transmission data.

[0060] Note that time synchronization between the controllers 2 may be performed autonomously between the controllers 2 using, for example, the IEEE 1588 Precision Time Protocol. Also, the communication processing unit 113 may notify each controller 2 of the period C1 and time segments t1 to t5, and control each controller 2 to communicate at the timing shown in FIG.

[0061] [Communication processing] Hereinafter, an example of the procedure of the communication process executed in the communication system 10 according to the first embodiment will be described with reference to FIG.

[0062] The present invention can be understood as a communication method that executes one or more steps included in the communication process, and one or more steps included in the communication process described herein may be omitted as appropriate. The steps in the communication process may be executed in a different order as long as the same effects are achieved. Furthermore, while the present invention will be described here as an example in which the steps in the communication process are executed by the management server 1 and the controller 2, another embodiment may also be a communication method in which multiple processors execute the steps in the communication process in a distributed manner.

[0063] Here, the communication methods shown in Figures 8 and 9 will be described as examples. Using a predetermined channel CH1, the control unit 11 of the management server 1 outputs a transmission instruction for transmission data (see Figure 8) to each of the controllers A to E assigned to each of five time segments t1 to t5 (40 ms each) obtained by time-dividing a predetermined period (200 ms).

[0064] First, when the first cycle (N=1) starts (S1), in step S2, the control unit 11 determines whether the first time segment t1 has started. When the first time segment t1 starts (S2: Yes), in step S3, the control unit 11 outputs a transmission instruction for the transmission data to the controller A. When the controller A receives the transmission instruction, it transmits the transmission data, which includes the tag Tg (e.g., tags 1 to 5) that will execute the command as its destination, to all tags Tg (see FIG. 5) associated with the controller A.

[0065] Next, in step S4, the control unit 11 determines whether or not a response (acknowledgement) from the tag Tg has been received. For example, when tags 1 to 5 receive the transmission data, execute a command (light-up command), and transmit a response to the controller A, the controller A transmits the received response to the management server 1. As a result, the control unit 11 of the management server 1 receives the response. When the control unit 11 receives the response (S4: Yes), the process proceeds to step S5.

[0066] In step S5, the control unit 11 determines whether the second time segment t2 has started. When the second time segment t2 has started (S5: Yes), in step S6, the control unit 11 outputs a transmission instruction for the transmission data to the controller B. When the controller B acquires the transmission instruction, it transmits the transmission data, which includes the tag Tg (e.g., tags 6 to 10) that will execute the command as a destination, to all tags Tg (see FIG. 5) associated with the controller B.

[0067] Next, in step S7, the control unit 11 determines whether or not a response from the tag Tg has been received. For example, when the tags 6 to 10 receive the transmission data, execute a command (a turn-on command), and transmit a response to the controller B, the controller B transmits the received response to the management server 1. As a result, the control unit 11 of the management server 1 receives the response. When the control unit 11 receives the response (S7: Yes), the process proceeds to step S8.

[0068] In step S8, the control unit 11 determines whether the third time segment t3 has started. When the third time segment t3 has started (S8: Yes), in step S9, the control unit 11 outputs a transmission instruction for the transmission data to the controller C. When the controller C acquires the transmission instruction, it transmits the transmission data, which includes the tag Tg (e.g., tags 11 to 15) that will execute the command as a destination, to all tags Tg (see FIG. 5) associated with the controller C.

[0069] Next, in step S10, the control unit 11 determines whether or not a response has been received from the tag Tg. For example, when the tags 11 to 15 receive the transmission data, execute a command (a turn-on command), and transmit a response to the controller C, the controller C transmits the received response to the management server 1. As a result, the control unit 11 of the management server 1 receives the response. When the control unit 11 receives the response (S10: Yes), the process proceeds to step S11.

[0070] In step S11, the control unit 11 determines whether the fourth time segment t4 has started. When the fourth time segment t4 has started (S11: Yes), in step S12, the control unit 11 outputs a transmission instruction for the transmission data to the controller D. When the controller D acquires the transmission instruction, it transmits the transmission data, which includes the tag Tg (e.g., tags 16 to 20) that will execute the command as its destination, to all tags Tg (see FIG. 5) associated with the controller D.

[0071] Next, in step S13, the control unit 11 determines whether or not a response has been received from the tag Tg. For example, when the tags 16 to 20 receive the transmission data, execute a command (a turn-on command), and transmit a response to the controller D, the controller D transmits the received response to the management server 1. As a result, the control unit 11 of the management server 1 receives the response. When the control unit 11 receives the response (S13: Yes), the process proceeds to step S14.

[0072] In step S14, the control unit 11 determines whether the fifth time segment t5 has started. When the fifth time segment t5 has started (S14: Yes), in step S15, the control unit 11 outputs a transmission instruction for the transmission data to the controller E. When the controller E acquires the transmission instruction, it transmits the transmission data, which includes the tag Tg (e.g., tags 21 to 25) that will execute the command as its destination, to all tags Tg (see FIG. 5) associated with the controller E.

[0073] Next, in step S16, the control unit 11 determines whether or not a response from the tag Tg has been received. For example, when the tags 21 to 25 receive the transmission data, execute a command (a turn-on command), and transmit a response to the controller E, the controller E transmits the received response to the management server 1. As a result, the control unit 11 of the management server 1 receives the response. When the control unit 11 receives the response (S16: Yes), the process returns to step S1.

[0074] Returning to step S1, the second cycle (N=2) starts, and in step S2, the control unit 11 determines whether the first time segment t1 has started. If the first time segment t1 has started (S2: Yes), in step S3, the control unit 11 outputs a transmission instruction to the controller A to transmit the transmission data. Upon receiving the transmission instruction, the controller A transmits the transmission data, which includes the tag Tg (e.g., tags 1 to 5) that will execute the command as a destination, to all tags Tg (see FIG. 5) associated with the controller A. The subsequent processing is the same as that described above. In this way, the communication system 10 executes the communication processing.

[0075] As described above, the communication system 10 according to the first embodiment is a communication system in which a plurality of controllers 2 (master stations) and a plurality of tags Tg (slave stations) perform wireless communication at a predetermined cycle. The communication system 10 associates each of the plurality of tags Tg with one of the plurality of controllers 2. The communication system 10 assigns each of the plurality of controllers 2 to a plurality of time segments (time slots) obtained by time-dividing the predetermined cycle on a predetermined channel. The communication system 10 also causes the controller 2 to communicate with the plurality of tags Tg associated with the controller 2 within each of the plurality of time segments.

[0076] In the above configuration, each controller 2 uses radio waves only during the time segment (40 ms) of the cycle (e.g., 200 ms). Furthermore, by allocating (adjusting) the radio wave usage times between controllers 2 so that they do not overlap, one channel (CH1) can be shared by up to five controllers 2. This makes it possible to install multiple controllers 2 even if their communication areas AR overlap, as shown in Figure 11. For example, if there are 20 frequency channels, it is possible to install 100 controllers 2, which is five times the number of channels, even in areas where there is radio wave interference between each other.

[0077] It may be desirable to allocate channels to each controller 2 while considering the maximum number of channels that can be shared, depending on the factory layout and the type of each line. In such a case, a display screen (UI) may be provided that allows the number of each controller (here, "1" to "64" as an example) to be mapped and set on a table with time slots (slot numbers) and channels (frequency channels) set vertically and horizontally, as shown in Figure 12. In other words, the control unit 11 may visually distinguishably display the predetermined channels and predetermined time segments to which each of the multiple controllers 2 (master stations) is assigned.

[0078] Furthermore, the transmission data includes destination information for multiple tags Tg. According to the above configuration, using one channel, each controller 2 can communicate with multiple tags Tg in each time segment assigned to multiple controllers 2 in each period. This allows multiple tags Tg to be installed over a wide area. Furthermore, the communication volume can be increased in the communication system 10. This makes it possible to install multiple tags Tg while ensuring high-speed responsiveness of communication between the controller 2 and the tags Tg.

[0079] In the communication system 10 according to this embodiment, the multiple controllers 2 (master stations) synchronize their time with each other and communicate within the time segments assigned by the assignment processing unit 112. The multiple controllers 2 may also be connected to each other by wired communication.

[0080] Furthermore, when data to be transmitted occurs in a tag Tg (slave station), the communication processing unit 113 causes the controller 2 associated with the tag Tg to transmit the data within the time segment assigned to the controller 2.

[0081] Furthermore, the data to be transmitted by the tag Tg is data observed by the tag Tg. Furthermore, the data observed by the tag Tg is data corresponding to the operation content of the user interface of the tag Tg.

[0082] The present invention is not limited to the above-described embodiment and may be embodied as follows. For example, the communication system 10 may include multiple channels. In this case, the allocation processing unit 112 allocates each of the multiple controllers 2 to a respective one of multiple time segments for each channel. As a result, for example, five controllers A to E share channel CH1, five controllers F to J share channel CH2, five controllers K to O share channel CH3, five controllers P to T share channel CH4, and five controllers U to Y share channel CH5. As in the above-described embodiment, each controller 2 communicates with multiple tags Tg in each of multiple time segments obtained by time-dividing a predetermined period. With this configuration, the number of controllers 2 installed can be increased according to the number of available channels, allowing for the installation of more tags Tg.

[0083] In the above embodiment, a 200 ms period is divided into five 40 ms slots, but this is just an example. The period, the number of divisions, and the slot time can be set appropriately taking into consideration the time response, power consumption, number of slave stations, number of available frequency channels, communication speed, etc. required for each application.

[0084] Furthermore, in the above-described embodiment, the management server 1 (arbitration station) is configured to control multiple controllers 2. However, in another embodiment, a specific controller 2 among the multiple controllers 2 may also function as the management server 1. In this case, the specific controller 2 functions as the master controller, and the other controllers 2 function as slave controllers. The master controller performs an assignment process to assign each of the multiple slave controllers to a respective one of multiple time segments on a predetermined channel, and a communication process to allow the slave controller to communicate with multiple tags Tg in each of the multiple time segments. The master controller transmits the transmission data to each slave controller in the order of the time segments. Note that the controller 2 functioning as the master controller may be changed as appropriate depending on the communication status of the entire communication system 10.

[0085] [Embodiment 2] A communication system 10 according to a second embodiment of the present invention will be described. In the following, the same configurations and processes as those of the communication system 10 according to the first embodiment will be assigned the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0086] The communication system 10 according to the second embodiment is a system that, when constructing a large number of star topology networks each consisting of a controller 2 and a plurality of tags Tg, enables each of the plurality of tags Tg to be associated with a specific controller 2 with which communication is stable, using a simple configuration. Each tag Tg is associated with one of the controllers 2. The "association" of the tag Tg and the controller 2 is also called "linking" or "binding."

[0087] Fig. 13 is a functional block diagram showing a schematic configuration of a communication system 10 according to a second embodiment of the present invention. The configuration shown in Fig. 13 shows a state before each of the multiple tags Tg is associated with one of the controllers 2. Note that the configuration shown in Fig. 1 shows a state after each of the multiple tags Tg is associated with one of the controllers 2.

[0088] The communication system 10 includes a management server 1, a plurality of controllers 2, and a plurality of tags Tg. Note that one or more of the plurality of controllers 2 may have the functions of the management server 1. In other words, the management server 1 may be the controller 2.

[0089] For example, a tag Tg1 (an example of a first slave station of the present invention) among multiple tags Tg transmits a search signal including identification information (tag ID) of the tag Tg1 to identify a controller 2 (an example of a first master station of the present invention) corresponding to the tag Tg1. Upon receiving the search signal transmitted from the tag Tg1, each of the multiple controllers 2 transmits an analysis report to the management server 1 including its own identification information (controller ID), the identification information (tag ID) of the tag Tg1, and signal information related to the search signal (e.g., the reception strength of the search signal). Based on the multiple analysis reports received from the multiple controllers 2, the management server 1 determines the controller 2 (e.g., controller A) corresponding to the tag Tg1 from among the multiple controllers 2, and associates the tag Tg1 with the controller A. The communication system 10 performs the above process for each tag Tg, and associates each tag Tg with one of the controllers 2.

[0090] A specific configuration of the communication system 10 according to the second embodiment will be described below. In the second embodiment, a 200 ms period is divided into 16 slots of 12.5 ms each. In other words, one frequency channel can be shared by up to 16 controllers.

[0091] Fig. 14 shows a specific example of the process of associating a target tag Tg (target tag Tg) to be associated with any controller 2. Fig. 15 shows an example of the procedure for the process of associating the management server 1, multiple controllers 2, and the target tag Tg. Note that Fig. 14 includes step numbers (s1, s5, s6, s9, s10) corresponding to the processing steps in Fig. 15.

[0092] In FIG. 14, for example, controller A transmits transmission data (commands) to a predetermined number (up to 5) of tags Tg that are already associated with controller A in an operation channel in which a slot of "12.5 ms" is set. Controller A switches "187.5 ms" of "200 ms" excluding "12.5 ms" to the search channel. Controller A becomes able to receive a search signal transmitted from a target tag Tg in the search channel (standby state). Controller B and other controllers have the same configuration as controller A.

[0093] In the association process, first, the target tag Tg transmits a search signal (step s1 in FIG. 15). Specifically, the target tag Tg transmits the search signal when it receives a predetermined user operation. For example, when the user presses the bottom button E1 (see FIG. 3B) of the target tag Tg, the target tag Tg receives the user's pressing operation and transmits the search signal. The target tag Tg transmits the search signal on the search channel. The target tag Tg also transmits the search signal multiple times at time intervals (e.g., 15 ms intervals) longer than the slot time (here, 12.5 ms) in time-division communication assigned to each controller 2. Here, the target tag Tg transmits the search signal four times at 15 ms intervals on the search channel. In this way, the controller 2 performs time-division communication with the tag Tg, and the tag Tg transmits the search signal multiple times at time intervals longer than the slot time in the time-division communication. By making the transmission interval of the search signal longer than the slot time, all controllers 2 can receive the search signal at least multiple times.

[0094] Each of the controllers 2 receives the search signal transmitted from the target tag Tg while waiting for reception on the search channel. For example, among all the controllers 2 installed in the facility F1, the controllers 2 installed in locations where the signal from the target tag Tg can reach receive the search signal.

[0095] When the controllers 2 receive the search signal, each of them transmits an analysis report to the management server 1, including the identification information (controller ID) of the controller 2, the identification information (tag ID) of the tag Tg, and signal information (e.g., reception strength) related to the search signal (step s2 in FIG. 15). The analysis report also includes the time when the search signal was received and the search signal number (information indicating the number of transmissions out of four, if the number of transmissions is four). Based on this, the management server 1 can obtain the reception start time at which the tag Tg starts receiving on the announce channel. Note that, since it is desirable for the target tag Tg to be associated with a controller 2 with sufficiently stable communication, the controller 2 may be configured not to transmit an analysis report corresponding to the search signal whose reception strength is below a predetermined value.

[0096] When the management server 1 receives the analysis reports from each controller 2, it determines the controller 2 to associate with the target tag Tg (step s3 in FIG. 15). Specifically, the associated processing unit 111 of the management server 1 determines the controller 2 to associate with the target tag Tg based on the stability of the search signal. For example, the associated processing unit 111 compiles the analysis reports corresponding to the target tag Tg, and when, for example, three or more of all the search signals from the first to the last (here, the fourth) have been received, it determines the controller 2 whose search signal is the most stable. The associated processing unit 111 calculates the stability of the search signal based on the average value of the signal strength of the search signal. Alternatively, the associated processing unit 111 may calculate the stability of the search signal based on the average value of the signal strength of the search signal, the minimum strength, the variance of the signal strength, etc.

[0097] Once the associated processing unit 111 has determined the controller 2, it transmits an association schedule (Bind schedule) for associating the target tag Tg to the controller 2 (step s4 in FIG. 15). Here, the associated processing unit 111 determines controller B as the controller 2 to associate with the target tag Tg, and transmits the association schedule to controller B. The association schedule includes at least the address of controller B and the reception start time (one second after the time the last search signal was transmitted) at which the target tag Tg will begin receiving on the announce channel. Note that it is preferable to transmit the association schedule within a predetermined time immediately after the slot time, as this reduces the possibility of multiple collisions with search signals transmitted at 15 ms intervals.

[0098] Controller B, which has received the association schedule from management server 1, transmits an association instruction (Bind instruction) to the target tag Tg via the announcement channel at the reception start time included in the association schedule (step s5 in FIG. 15). The association instruction includes at least the address of the target tag and the address of controller B to associate it with, and if there are multiple operating channels, it also includes information on the operating channel assigned to controller B.

[0099] When the reception start time arrives, the target tag Tg receives the association instruction on the announcement channel. When the target tag Tg receives the association instruction addressed to its own address, it switches to the specified operating channel and periodically receives beacons (which may include a command to turn on the tag) output by the controller B. After switching to the operating channel, when the target tag Tg receives a command addressed to itself, it executes the command and returns an acknowledgement signal (Acknowledge) to the controller B (step s6 in FIG. 15).

[0100] When the controller B receives the confirmation signal from the target tag Tg, it sends a confirmation notification to the management server 1 (step s7 in FIG. 15). When the management server 1 receives the confirmation notification from the controller B, it returns a completion instruction to the controller B (step s8 in FIG. 15). When the controller B receives the completion instruction from the management server 1, it sends a completion display instruction to the target tag Tg (step s9 in FIG. 15).

[0101] When the target tag Tg receives the completion display instruction from the controller B, it returns an acknowledgement signal (Acknowledge) to the controller B (step s10 in FIG. 15) and displays the completion (step s11 in FIG. 15). For example, the target tag Tg lights up the lamp button B1 (see FIG. 3A).

[0102] Finally, the management server 1 registers the association information between the target tag Tg and the controller B in the association information D2 (see FIG. 5) (step s12 in FIG. 15). Note that the registration in the management server 1 may be performed when the management server 1 receives the confirmation notification (step s7 in FIG. 15).

[0103] The communication system 10 performs the above-described process for each tag Tg and associates each tag Tg with one controller 2. In this way, the management server 1 notifies the target tag Tg of at least the identifier or communication channel of the controller B, and the target tag Tg communicates with the controller B based on at least the identifier or communication channel of the controller B. Furthermore, in the communication system 10, the channel on which the target tag Tg transmits the search signal is different from the channel on which the target tag Tg communicates with the controller B after being associated with the controller B.

[0104] [Association process] An example of the procedure of the association process executed in the communication system 10 according to the second embodiment will be described below with reference to Fig. 16 to Fig. 18. Fig. 16 shows an example of the procedure of the association process executed in the target tag Tg, Fig. 17 shows an example of the procedure of the association process executed in the controller 2, and Fig. 18 shows an example of the procedure of the association process executed in the management server 1.

[0105] [Association process for target tag Tg] The target tag Tg is initially in a substantially dormant state, and determines whether the bottom button E1 has been pressed in step S21 shown in Fig. 16. If the bottom button E1 has been pressed (S21: Yes), the target tag Tg enters an active state and shifts the process to step S22. The target tag Tg waits in a dormant state until the bottom button E1 is pressed (S21: No).

[0106] In step S22, the target tag Tg switches to the search channel. In the following step S23, the target tag Tg transmits the search signal multiple times at predetermined intervals (step s1 in FIG. 15). For example, the target tag Tg transmits the search signal four times at 15 ms intervals on the search channel. After transmitting the last (fourth) search signal, the target tag Tg waits until a predetermined time (1 second) has elapsed (S24).

[0107] Next, in step S25, the target tag Tg switches from the search channel to the announcement channel. Next, in step S26, the target tag Tg attempts to receive the association instruction from the controller 2 (controller B determined by the management server 1) for 500 ms. If the target tag Tg receives the association instruction (S26: Yes) (step s5 in FIG. 15), it transitions the process to step S27. On the other hand, if the target tag Tg does not receive the association instruction within the 500 ms (S26: No), it transitions the process to step S21.

[0108] In step S27, the target tag Tg switches from the announcement channel to the operating channel specified in the association instruction, and receives the beacon from the controller B in synchronization based on the address of the controller B obtained in the association instruction.

[0109] Next, in step S28, the target tag Tg determines whether or not it has received a command addressed to itself from the controller B. If the target tag Tg receives a command addressed to itself from the controller B (S29: Yes), it shifts the process to step S30. On the other hand, if the target tag Tg does not receive a command addressed to itself from the controller B (S29: No), it shifts the process to step S21.

[0110] Next, in step S30, the target tag Tg transmits the confirmation signal to the controller B (step s6 in FIG. 15). After that, when the target tag Tg receives the completion display instruction from the controller B, it returns the confirmation signal to the controller B and lights up the lamp button B1 (see FIG. 3A) (S30) (steps s9 and s10 in FIG. 15).

[0111] [Association process on Controller 2] 17, the controller 2 (here, the controller B is taken as an example) sets the operating channel assigned to itself. Next, in step S32, the controller B executes the operation process instructed by the management server 1. For example, the controller B transmits transmission data (commands) to a predetermined number of tags Tg out of the multiple tags Tg that have already been associated.

[0112] Next, when the predetermined operation time (slot time "12.5 ms") has elapsed (S33: Yes), the controller B shifts the process to step S34.

[0113] In step S34, the controller B determines whether the reception start time has arrived, at which the target tag Tg starts receiving on the announcement channel (the time one second after the target tag Tg transmitted the last search signal). If the reception start time has arrived (S34: Yes), the controller B switches from the operating channel to the announcement channel (S35) and transmits the association instruction to the target tag Tg (S36) (step s5 in FIG. 15). If the reception start time has not arrived (S34: No), the controller B proceeds to step S37.

[0114] In step S37, the controller B switches from the announcement channel to the search channel. Next, in step S38, the controller B determines whether or not the search signal has been received from the target tag Tg. If the controller B receives the search signal (S38: Yes), the controller B shifts the process to step S39. If the controller B does not receive the search signal (S38: No), the controller B shifts the process to step S40.

[0115] In step S39, the controller B transmits the analysis report to the management server 1 (step s2 in FIG. 15). For example, the controller B transmits four analysis reports to the management server 1.

[0116] Next, in step S40, controller B determines whether the operation start time has arrived. When the operation start time has arrived (S40: Yes), controller B returns to step S31 and switches to the operation channel. Controller B repeats the processes of steps S38 and S39 until the operation start time has arrived (S40: No). Each controller 2 repeatedly executes the above-mentioned processes.

[0117] [Association process on Management Server 1] 18, the management server 1 determines whether or not it has received the analysis reports from a plurality of controllers 2. For example, the management server 1 receives a plurality of analysis reports (corresponding to three or four search signals) from the controller B.

[0118] When the management server 1 receives the plurality of analysis reports from the plurality of controllers 2 (S41: Yes), it aggregates the plurality of analysis reports (S42) and determines the controller 2 to associate with the target tag Tg (S43) (step s3 in FIG. 15). For example, the management server 1 identifies the minimum reception strength of the plurality of search signals for each controller 2, and determines the controller 2 with the highest minimum reception strength. Then, the management server 1 determines the controller 2 with the highest minimum reception strength as the controller 2 to associate with the target tag Tg.

[0119] When the management server 1 determines one controller 2 (here, controller B) (S43), in step S44, it transmits an association plan (Bind plan) for associating the target tag Tg to controller B (step s4 in FIG. 15).

[0120] When the controller B receives the association schedule, it transmits an association instruction (Bind instruction) to the target tag Tg to associate with the target tag Tg. This process corresponds to the communication process in step S36 in FIG.

[0121] When the management server 1 completes confirmation of the association between the target tag Tg and the controller B, it registers the association information between the target tag Tg and the controller B in the association information D2 (see FIG. 5) (S45) (step s12 in FIG. 15). The management server 1 repeatedly executes the above-mentioned process every time it receives the analysis report from the controller 2.

[0122] As described above, the communication system 10 according to the second embodiment is a communication system including a management server 1, multiple controllers 2 (master stations), and multiple tags Tg (slave stations). Furthermore, the first tag Tg transmits a search signal to identify the first controller 2 corresponding to the first tag Tg. Upon receiving the search signal, each of the multiple controllers 2 transmits an analysis report to the management server 1, the analysis report including identification information of the controller 2, identification information of the first tag Tg, and signal information related to the search signal. Based on the multiple analysis reports received from each of the multiple controllers 2, the management server 1 determines the first controller 2 corresponding to the first tag Tg from among the multiple controllers 2, and associates the first tag Tg with the first controller 2.

[0123] According to the above configuration, by compiling analysis reports from the controller 2 that have received a search signal transmitted from the tag Tg in response to a predetermined event (e.g., a user operation), it becomes possible to associate a large number of tags Tg with each other through a simple operation such as pressing a button on the tag Tg. In other words, it becomes possible to associate the controller 2 and multiple tags Tg with each other through a simple configuration. Furthermore, since the tag Tg only needs to receive an association instruction within a predetermined time after transmitting the search signal multiple times, the communication load and battery consumption of the tag Tg can be reduced. Furthermore, by appropriately entering sleep (hibernation mode) when not communicating, battery consumption can be further reduced.

[0124] In another embodiment of the present invention, the tag Tg may transmit the search signal when it receives a predetermined signal. For example, the tag Tg transmits the search signal when it receives an instruction to transmit the search signal from the management server 1.

[0125] Furthermore, the tag Tg may transmit the search signal when a predetermined time has elapsed. For example, the tag Tg transmits the search signal when a preset time has elapsed. This allows the tag Tg to periodically perform the association process and associate with the optimal controller 2.

[0126] The tag Tg may also transmit the search signal when communication becomes unstable. For example, the tag Tg transmits the search signal when the beacon reception conditions deteriorate, i.e., when the received signal level drops below a predetermined level, or when a predetermined condition occurs in which beacon reception fails. This allows the tag Tg to associate with the optimal controller 2 even if the conditions change due to a change in location, etc., and prevents the tag Tg from becoming unable to operate.

[0127] Furthermore, when transmitting the search signal, the tag Tg may perform carrier sensing and transmit if the carrier is available, and may retry if the carrier is not available. This makes it possible to efficiently associate multiple tags Tg at the same time.

[0128] Furthermore, it is even more preferable to perform random backoff by assigning random numbers during the retry.

[0129] In this way, the tag Tg transmits the search signal when it receives a user operation, when it receives a specified signal, when the stability of the signal from the controller 2 associated with the tag Tg reaches a specified state, or when a specified time has passed.

[0130] As described above, the communication system of the present invention may be configured as the entire communication system 10 (see Figure 1) including the management server 1, controller 2, and tag Tg, or may be configured as the management server 1 and controller 2, or may be configured as the management server 1 alone or the controller 2 alone.

[0131] Furthermore, the channel (frequency channel) of the present invention can also be applied to communication methods such as frequency hopping and direct sequence spread spectrum.

[0132] In addition, in the present invention, the channel (operation channel) used to send commands to the tag Tg (slave station) by beacon to control it is different from the channel (search channel) used to send the search signal. By separating the channels used in this way, it is possible to avoid any impact on normal operation.

[0133] Furthermore, the present invention further includes a channel (announce channel) for transmitting a signal instructing association between the tag Tg and the controller 2, and the announce channel is different from the operation channel and the search channel. In this way, by separating the use channels, it is possible to avoid any influence on normal operation.

[0134] Furthermore, in the present invention, if communication with the first master station associated with the first slave station becomes unstable, the tag Tg transmits the search signal to re-establish association, which enables the tag Tg to re-associate with a better controller 2 in response to changes in the environment, such as a change in installation location.

[0135] Furthermore, the communication system according to the present invention can be constructed by freely combining the above-described embodiments within the scope of the invention described in each claim, or by appropriately modifying or omitting parts of each embodiment. [Explanation of symbols]

[0136] 1: Management Server 2: Controller 10: Communication Systems 111: Related processing unit 112: Allocation processing unit 113: Communication processing unit C1 :Period Tg : tag t1: 1st time segment t2: 2nd time segment t3: Third time slot t4: 4th time segment t5: 5th time segment

Claims

1. A communication system including a management server, a plurality of master stations, and a plurality of slave stations, the first slave station transmits a search signal for identifying the first master station corresponding to the first slave station; When each of the plurality of master stations receives the search signal, the master station transmits a report to the management server, the report including identification information of the master station, identification information of the first slave station, and signal information related to the search signal; the management server determines the first master station corresponding to the first slave station from among the plurality of master stations based on the plurality of reports received from each of the plurality of master stations, and associates the first slave station with the first master station. Communication system.

2. the management server determines the first master station corresponding to the first slave station based on the stability of the search signal; The communication system of claim 1 .

3. The stability of the search signal is calculated based on either a signal strength value of the search signal or an average value of the signal strength. The communication system according to claim 2 .

4. the management server notifies the first slave station of at least an identifier or a channel of the first master station; the first slave station communicates with the first master station based on at least an identifier or a channel of the first master station; The communication system according to any one of claims 1 to 3.

5. a channel through which the first slave station transmits the search signal is different from a channel through which the first slave station communicates with the first master station after being associated with the first master station; The communication system according to any one of claims 1 to 4.

6. the first slave station transmits the search signal when it receives a predetermined user operation, when it receives a predetermined signal, when the stability of the signal from the first master station associated with the first slave station reaches a predetermined state, or when a predetermined time has elapsed. The communication system according to any one of claims 1 to 5.

7. the master station performs time-division communication with the slave station; the first slave station transmits the search signal a plurality of times at time intervals longer than a slot time in the time division communication; A communication system according to any one of claims 1 to 6.

8. the management server is one of the plurality of master stations; A communication system according to any one of claims 1 to 7.

9. a channel for transmitting a command to the first slave station by a beacon to control the first slave station is different from a channel for transmitting the search signal from the first slave station; A communication system according to any one of claims 1 to 8.

10. a channel for transmitting a signal instructing association between the first slave station and the first master station, the channel being different from a channel for transmitting a command to the first slave station by a beacon to control the first slave station and a channel for transmitting the search signal from the first slave station; 10. The communication system of claim 9.

11. When communication with the first master station associated with the first slave station becomes unstable, the first slave station transmits the search signal to re-establish association. A communication system according to any one of claims 1 to 10.

12. A communication method for wireless communication between a management server, a plurality of master stations, and a plurality of slave stations, comprising: a first slave station transmits a search signal for identifying a first master station corresponding to the first slave station; When each of the plurality of master stations receives the search signal, the master station transmits a report to the management server, the report including identification information of the master station, identification information of the first slave station, and signal information related to the search signal; the management server determines the first master station corresponding to the first slave station from among the plurality of master stations based on the plurality of reports received from each of the plurality of master stations, and associates the first slave station with the first master station; Communication method.

Images