JP2020123844A - Wireless communication device, wireless communication method, and wireless communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce duplication of transmission timing between routers and to reduce the amount of data stored in a router. A router 10 includes a storage unit 150, a first receiving unit, a first calculation unit, a first transmitting unit, and a second transmitting unit. The storage unit stores the identification information of one or a plurality of first routers located downstream and directly connected to the router 10. The first receiver receives a data request from the second router. The first calculation unit calculates the first collection remaining number. When the first transmitting unit receives the data request, the data request is transmitted to one of the first routers, and the data collection from the first destination router is completed. If the first remaining collection number is other than 0, the data request is transmitted to the other one of the first routers. The second transmission unit transmits the data collected from the first router and the remaining number of collected data to the second router. [Selection diagram] Fig. 3

Description

Embodiments of the present invention relate to a wireless communication device, a wireless communication method, and a wireless communication system.

Conventionally, a multi-hop network has been known in which a wireless communication device (hereinafter, referred to as a router) having a relay function sends data to a coordinator while relaying each other's data. In such a multi-hop network, since the data transmission timing of each router is not centrally managed, data may be simultaneously transmitted from a plurality of routers to one router. If the transmission timings overlap as described above, the data transmitted from any of the routers may be lost without being received by the destination router.

Therefore, for example, a technique is known in which the coordinator manages the transmission timings of all the routers included in the multi-hop network to reduce overlapping of transmission timings from a plurality of routers with respect to one router. ing.

JP, 2018-006960, A

However, in the prior art, since the coordinator and each router store in advance the identification information of all the routers under the control of the coordinator and each router, and the route information for reaching all the routers under the control of each router or coordinator. In some cases, the amount of data stored in the memory may increase.

The present invention has been made in view of the above, and an object thereof is to reduce duplication of transmission timing between routers and reduce the amount of data stored in the routers.

A wireless communication device according to an embodiment is a wireless communication device connected to a multi-hop network, and includes a storage unit, a first receiving unit, a first calculating unit, a first transmitting unit, and a second transmitting unit. And a section. The storage unit stores identification information of one or a plurality of first wireless communication devices located downstream of the wireless communication device in the multi-hop network and directly connected to the wireless communication device. The first receiving unit receives a data request from a second wireless communication device located upstream of the wireless communication device in the multi-hop network. The first calculator calculates the first remaining number of collections, which is the number of first wireless communication devices for which data collection has not been completed. When the first transmission unit receives the data request, the first transmission unit transmits the data request to one of the first wireless communication devices based on the identification information stored in the storage unit, and the first transmission destination In the case where the data collection from the wireless communication device is completed and the first remaining number of collection is other than 0, the data request is transmitted to another one of the first wireless communication devices. The second transmission unit transmits the data collected from the first wireless communication device and the first remaining number of collections to the second wireless communication device.

FIG. 1 is a diagram showing an example of the overall configuration of a wireless communication system according to an embodiment. FIG. 2 is a diagram illustrating an example of a hardware configuration of the router and the coordinator according to the embodiment. FIG. 3 is a block diagram showing an example of the functional configuration of the router according to the embodiment. FIG. 4 is a diagram illustrating an example of the connection information database according to the embodiment. FIG. 5 is a block diagram showing an example of the functional configuration of the coordinator according to the embodiment. FIG. 6 is a sequence diagram showing an example of the flow of sensor data collection processing according to the embodiment.

FIG. 1 is a diagram showing an example of the overall configuration of a wireless communication system S according to the present embodiment. As shown in FIG. 1, the wireless communication system S includes a plurality of routers 10a to 10h (hereinafter, the routers 10a to 10h will be referred to as routers 10 unless otherwise specified) and a coordinator 20. At least one coordinator 20 is provided in one wireless communication system S.

In the present embodiment, in the wireless communication system S, each router 10 is classified into levels such that the level value decreases as the distance from the coordinator 20 decreases. The short distance between the coordinator 20 and the router 10 means that the coordinator 20 and the router 10 are connected with a small number of relays (that is, the number of hops).

Specifically, the routers 10a and 10b directly connected to the coordinator 20 are level 1, the routers 10c to 10e directly connected to the level 1 routers 10a and 10b are level 2, and the routers directly connected to the level 2 routers 10c to 10e. Levels 10f to 10h are set to level 3.

Further, in the present embodiment, the closer the router 10 is to the coordinator 20, the higher the router is, and the farther the router 10 is from the coordinator 20, the lower the router 10 is. The wireless communication system S of the present embodiment constitutes a multi-hop network in which each router 10 relays the data transmitted by the lower router 10 and delivers the data to the coordinator 20. The router 10 and the coordinator 20 are also called nodes. The coordinator 20 is also called a root.

More specifically, the wireless communication system S is a tree-type multi-hop network in which the highest node (that is, the coordinator 20) is connected to the lower node (that is, the router 10) and the lower node is connected to the lower node. Is. The connection relationship between the coordinator 20 and the router 10 is automatically or manually determined in advance.

Further, among the other routers 10 positioned higher than the router 10 on the multi-hop network, the other router 10 directly connected to the router 10 is referred to as a “parent router”. Further, among the other routers 10 positioned lower than the router 10 on the multi-hop network, the other router 10 that is directly connected to the router 10 is referred to as a “direct router”. When the router directly under the router 10 and other lower routers connected to the router 10 are collectively referred to as the router 10 under the router 10. Further, in the multi-hop network, the side closer to the coordinator 20 is called upstream, and the side farther from the coordinator 20 is called downstream.

For example, the router 10a is a parent router of the routers 10c and 10d. The routers directly under the router 10a are the router 10c and the router 10d. The router 10c, the router 10d, the router 10f, and the router 10g are the routers 10 under the router 10a.

The coordinator 20 and the router 10 are wireless communication devices that perform wireless communication. The coordinator 20 and the router 10 are connected to each other by, for example, wireless communication using a wireless communication standard such as Bluetooth (registered trademark), Zigbee (registered trademark), and Wi-Fi (registered trademark).

The router 10 acquires sensor data from the sensors 30a to 30h (hereinafter, referred to as the sensor 30 when the individual sensors 30a to 30h are not particularly distinguished) installed around the router 10. When receiving a data request from the coordinator 20 or the upper router 10, the router 10 transmits the sensor data to the requesting coordinator 20 or the upper router 10.

The sensor 30 detects, for example, environmental information of a specific area. The environmental information is, for example, the atmospheric component, the temperature, the water temperature, the amount of light such as ultraviolet rays, the volume, and the like, but is not limited thereto. The sensor data is the detection result of the sensor 30. In the present embodiment, the sensor 30 transmits sensor data to the router 10 by wireless communication, but a configuration in which the router 10 and the sensor 30 perform wired communication may be adopted. The sensor 30 is also called an end device.

The coordinator 20 is a management device that controls the router 10 in the wireless communication system S. The coordinator 20 transmits a data request to the router 10 and collects the sensor data transmitted from the router 10.

Further, the coordinator 20 is connected to an external information processing device, for example, a PC (Personal Computer) 40 via a transmission path 41. The transmission line 41 is, for example, a transmission line conforming to a standard such as USB (Universal Serial Bus). The coordinator 20 transmits the sensor data collected from each router 10 to the PC 40.

Next, the hardware configurations of the router 10 and the coordinator 20 will be described. In the present embodiment, the router 10 and the coordinator 20 have the same hardware configuration.

FIG. 2 is a diagram showing an example of a hardware configuration of the router 10 and the coordinator 20 according to this embodiment. The router 10 and the coordinator 20 include a first wireless module 101, a second wireless module 102, a flash memory 103, a processor 104, a ROM (Read Only Memory) 105, a RAM (Random Access Memory) 106, The communication interface (I/F) 107 is provided. Further, the first wireless module 101, the second wireless module 102, the flash memory 103, the processor 104, the ROM 105, the RAM 106, and the communication interface 107 are connected by a bus 108.

The hardware configurations of the router 10 and the coordinator 20 are not limited to the example shown in FIG. For example, the hardware configuration of the router 10 and the coordinator 20 may be a configuration in which other hardware components centering around the processor 104 are connected in a star shape.

The first wireless module 101 wirelessly communicates with another router 10 or a coordinator 20. The second wireless module 102 also wirelessly communicates with the sensor 30. Further, the router 10 and the coordinator 20 may include other components that realize a wireless communication function instead of the first wireless module 101 and the second wireless module 102. For example, the router 10 and the coordinator 20 may include a NIC (Network Interface Card), a wireless LAN adapter, or the like.

The processor 104 is an arithmetic unit that controls the router 10 and the coordinator 20 of this embodiment. Further, the ROM 105 stores a program executed by the processor 104 and the like. Further, the RAM 106 and the flash memory 103 store information necessary for executing various processes by the processor 104, sensor data, and the like.

The communication interface 107 is an interface connected to an external device such as the PC 40, and is, for example, a USB port or the like.

The router 10 and the coordinator 20 may have different hardware configurations. In this case, the router 10 does not have to include the communication interface 107. Further, the coordinator 20 does not have to include the second wireless module 102.

Next, details of the function of the router 10 of the present embodiment will be described. FIG. 3 is a block diagram showing an example of the functional configuration of the router 10 according to this embodiment. As shown in FIG. 3, the router 10 includes an acquisition unit 111, a first reception unit 112, a first transmission unit 113, a second reception unit 114, a first calculation unit 115, and a second calculation unit 115. The transmission unit 116, the first clock unit 117, and the storage unit 150. It is assumed that each router 10 on the multi-hop network has the same function.

The storage unit 150 stores the connection information database (DB) 90a, the number of directly connected routers, the first remaining collection number, and sensor data acquired by the acquisition unit 111 described below. The storage unit 150 is, for example, the flash memory 103 or the RAM 106.

The connection information database 90a is a database in which identification information capable of specifying another router 10 or the coordinator 20 directly connected to the own device (router 10) is registered.

FIG. 4 is a diagram showing an example of the connection information database 90a according to the present embodiment. In the connection information database 90a shown in FIG. 4, parent router or coordinator identification information and direct router identification information are registered.

In the present embodiment, the last two digits of the MAC address of the router 10 or the coordinator 20 are used as the identification information that can identify the router 10 or the coordinator 20 on the multi-hop network, but the identification information is not limited to this. Not something.

The parent router or the coordinator identification information is identification information that can identify the other router 10 or the coordinator 20 directly connected to the router 10 among the other routers 10 or the coordinator 20 positioned higher than the router 10 on the multi-hop network. Is.

Since the multi-hop network of the present embodiment is a tree type, among other routers 10 or coordinators 20 positioned higher than the router 10 on the multi-hop network, another router 10 or a coordinator 20 that is directly connected to the router 10. Is one.

The contents registered in the connection information database 90a are different for each router 10. For example, it is assumed that the connection information database 90a shown in FIG. 4 is stored in the storage unit 150 of the router 10a. As shown in FIG. 1, the coordinator 20 is a node located higher than the router 10 a on the multi-hop network and directly connected to the router 10. In this case, the parent router or coordinator identification information of the connection information database 90a is the identification information “01” that can identify the coordinator 20.

Further, the direct router identification information is the identification information of one or a plurality of routers 10 that are directly connected to the own device among the other routers 10 under its own device (router 10) in the multi-hop network, that is, the direct router. When the router 10a is an example of the own device in this embodiment, the router 10c and the router 10d are the direct routers of the router 10a. In this case, the direct router identification information is the identification information “04” that can identify the router 10c and the identification information “05” that can identify the router 10d. The order in which the direct router is registered in the connection information database 90a is, for example, the order in which the direct router is connected to the multi-hop network.

The direct router is an example of the first wireless communication device in this embodiment. For example, when the router 10a is an example of the own device in the present embodiment, the router 10c and the router 10d are examples of the first wireless communication device, and the coordinator 20 is an example of the second wireless communication device.

Returning to FIG. 3, the number of direct routers is the number of direct routers of the router 10. The number of direct routers is equal to the number of routers 10 registered in the direct router identification information of the connection information database 90a.

The first remaining number of collection is the number of the direct routers of the router 10 that have not completed data collection yet. The first remaining collection number is calculated by the first calculation unit 115 described later.

In the present embodiment, the remaining collection number calculated by the first calculating unit 115 of the router 10 is the remaining collection number received from another router 10 or the remaining collection number calculated by the coordinator 20 (described later). In order to distinguish it from the second to fourth remaining collection number), the term "first collection remaining number" is used. Each of the first to fourth remaining collection numbers is the number of direct routers for which data collection has not been completed among the direct routers of the routers 10 for calculating the first to fourth remaining collection numbers. When the first to fourth remaining collection numbers are not particularly distinguished, the remaining collection numbers may be simply used.

Here, the completion of the data collection of the direct router means that the router 10 has received or timed out the sensor data acquired by the direct router of the router 10 and all the routers 10 under the direct router. ..

Further, the fact that the data collection of the direct router is not completed means that the router 10 has not received the sensor data acquired by the direct router of the router 10 or any of the routers 10 under the direct router, and It means that the data request for the unreceived sensor data has not timed out.

The acquisition unit 111 acquires sensor data from the sensor 30. The acquisition unit 111 stores the acquired sensor data in the storage unit 150.

The first receiving unit 112 receives a data request from another router 10 or a coordinator 20 located upstream of the router 10 (own device) on the multi-hop network. When receiving the data request, the first receiving unit 112 notifies the first transmitting unit 113, the first calculating unit 115, and the second transmitting unit 116 that the data request has been received.

The data request in this embodiment is a command signal that requests each router 10 to transmit the sensor data acquired from the sensor 30 to the parent router or the coordinator 20.

In this embodiment, the other router 10 or the coordinator 20 that transmits the data request to the router 10 is the parent router or the coordinator 20 identified by the parent router or the coordinator identification information registered in the connection information database 90a. Taking the router 10a as an example, the first receiving unit 112 of the router 10a receives a data request from the coordinator 20. Also, taking the router 10d as an example, the first receiving unit 112 of the router 10d receives a data request from the router 10a.

When the first receiving unit 112 receives the data request, the first transmitting unit 113 is one of the direct routers based on the direct router identification information registered in the connection information database 90a of the storage unit 150. Send a data request to.

When the first transmitter 113 has completed data collection from the destination direct router and the first remaining collection number stored in the storage unit 150 is other than 0, The data request is transmitted to the other one. Further, the first transmitting unit 113 determines that the data collection from the direct router is completed when the second remaining collection number received by the second receiving unit 114 from the direct router is 0.

In addition, when the first remaining collection number stored in the storage unit 150 is 0, the first transmission unit 113 determines that data collection from all direct routers has been completed, and data to the direct router is Finish sending the request.

The second receiving unit 114 receives, from the direct router, the sensor data and the number of routers 10 that have not completed data collection among the routers 10 directly connected to the direct router. In the present embodiment, the number of routers 10 for which data collection has not been completed among the routers 10 directly connected to the direct router is referred to as a second remaining collection number. The second receiving unit 114 sends the received second remaining collection number to the first transmitting unit 113 and the first calculating unit 115.

Further, in the present embodiment, the router 10 directly connected to the direct router is referred to as a third wireless communication device. For example, when the router 10a is used as a reference, the router 10f and the router 10g, which are directly connected to the router 10d that is a direct router of the router 10a, are examples of the third wireless communication device.

The first calculating unit 115 calculates the first remaining collection number, which is the number of direct routers for which data collection has not been completed. More specifically, when the first receiving unit 112 receives the data request, the first calculating unit 115 stores the number of directly connected routers in the storage unit 150 as the initial value of the first remaining collection number.

Further, the first calculation unit 115 determines that the data collection from the direct router is completed when the second remaining collection number received by the second receiving unit 114 from the direct router is 0. The first calculating unit 115 subtracts one unit from the number of direct routers (that is, the initial value of the first remaining collection number) every time the data collection from the direct router is completed, thereby performing the first collection. Calculate the remaining number.

Further, the first calculation unit 115 subtracts one unit from the first remaining number of collection even when the elapsed time measured by the first time counting unit 117 described later is equal to or longer than the predetermined time. The case where the elapsed time measured by the first time counting unit 117 is equal to or longer than the predetermined time is referred to as the case where the data request times out.

The second transmission unit 116 transmits the sensor data acquired by the acquisition unit 111, the sensor data collected from the direct router, and the first remaining collection number calculated by the first calculation unit 115 to the transmission source of the data request. It is transmitted to a certain router 10 or coordinator 20. The second transmission unit 116 specifies the other router 10 or the coordinator 20 that is the transmission source of the data request by the parent router or the coordinator identification information registered in the connection information database 90a.

Further, when the first receiving unit 112 receives the data request, the second transmitting unit 116 transmits the reception response to the other router 10 or the coordinator 20 which is the transmission source of the data request. The reception response is, for example, an ACK (ACKnowledgement) signal or the like.

The first timer 117 measures the elapsed time from when the first transmitter 113 sends a data request to the direct router to when the second receiver 114 receives a reception response from the direct router. The first timer 117 notifies the first calculator 115 that the data request has timed out, when the elapsed time becomes equal to or longer than the predetermined time.

Next, the details of the function of the coordinator 20 of this embodiment will be described. FIG. 5 is a block diagram showing an example of the functional configuration of the coordinator 20 according to this embodiment. As shown in FIG. 5, the coordinator 20 includes a third transmitter 211, a third receiver 212, a second calculator 213, a second timer 214, a communication unit 215, and a storage unit. And 250.

The storage unit 250 stores a connection information database (DB) 90b, the number of directly connected routers, a third remaining collection number, and sensor data received by a third receiving unit 212 described below. The storage unit 250 is, for example, the flash memory 103 or the RAM 106.

The connection information database 90b is a database in which identification information capable of specifying the router 10 or the coordinator 20 directly connected to the coordinator 20 (own device) is registered, like the connection information database 90a described above. In this case, since the coordinator 20, which is the own device, has no parent upper device, only the direct router identification information is registered in the connection information database 90b. Since the routers directly under control of the coordinator 20 are the router 10a and the router 10b, the connection information database 90b registers identification information that can identify the router 10a and identification information that can identify the router 10b.

The number of direct routers is the number of direct routers of the coordinator 20. The number of direct routers is equal to the number of routers 10 registered in the direct router identification information of the connection information database 90b.

The third remaining collection number is the number of the direct routers of the coordinator 20 whose direct data collection is incomplete. The third remaining collection number is calculated by the second calculation unit 213 described later.

The third transmission unit 211 transmits the data request to the router 10 directly connected to the coordinator 20, that is, the direct router among the routers 10 under the coordinator 20. It is assumed that the third transmission unit 211 specifies the transmission-destination direct router from the direct-router identification information registered in the connection information database 90b of the storage unit 250. Further, when the data collection from the destination router 10 is completed, the third transmission unit 211 transmits a data request to another direct router.

Further, the third transmission unit 211 ends the transmission of the data request to the direct router when the third remaining collection number calculated by the second calculation unit 213 described later becomes zero. Further, when the third receiving unit 212 receives the sensor data and the first remaining collection number from the direct router, the third transmitting unit 211 transmits a reception response to the direct router as the transmission source.

The third receiving unit 212 receives the sensor data and the first remaining collection number from the direct router that is the destination of the data request by the third transmitting unit 211. The third receiving unit 212 stores the received sensor data in the storage unit 250. When the third receiving unit 212 receives the sensor data and the first remaining number of collections, the third receiving unit 212 reports that the sensor data and the first remaining number of collections have been received by the third transmitting unit 211 and the second timer unit 214. To notify.

The second calculator 213 calculates the third remaining collection number, which is the number of direct routers for which data collection has not been completed, every time data collection from the direct router is completed. Completion of data collection from the direct router includes not only completion of reception of sensor data but also timeout of data request. Further, the second calculating unit 213 stores the number of direct routers in the storage unit 250 as an initial value of the third remaining collection number when starting the data request to the direct router.

The second timer 214 measures the elapsed time from when the third transmitter 211 transmits a data request to the direct router to when the third receiver 212 receives a reception response from the direct router. The second timer 214 notifies the second calculator 213 that the data request has timed out, when the elapsed time becomes equal to or longer than the predetermined time.

The communication unit 215 transmits the sensor data stored in the storage unit 250 to the PC 40. The communication unit 215 may periodically transmit the sensor data to the PC 40, or when the data collection of all the routers 10 is completed, that is, when the third remaining collection number becomes 0, the communication unit 215 sends the sensor data to the PC 40. You may send it to. Moreover, the communication unit 215 may transmit the sensor data to the PC 40 each time the third receiving unit 212 receives the sensor data from the direct router. Further, the communication unit 215 may receive a data collection instruction from the PC 40.

Next, a flow of sensor data collection processing executed in the wireless communication system S configured as above will be described.

FIG. 6 is a sequence diagram showing an example of the flow of sensor data collection processing according to the present embodiment. The process of this sequence diagram may be executed, for example, periodically, or when the coordinator 20 receives a data collection instruction from the PC 40. Further, it is assumed that the acquisition unit 111 of each router 10 stores the sensor data acquired from the sensor data in the storage unit 150 at the time when the process illustrated in this sequence diagram is executed.

Further, in FIG. 6, the remaining number of collections calculated by the first calculating unit 115 of the routers 10a and 10b is the first remaining number of collections, and the first calculating units of the routers 10c and 10d which are the direct routers of the router 10a. The remaining number of collections calculated by 115 is the second remaining number of collections, and the remaining number of collections calculated by the second calculating unit 213 of the coordinator 20 is the third remaining number of collections. In addition, the remaining number of collections calculated by the first calculating unit 115 of the router 10f that is a direct router of the router 10d is set as the fourth remaining number of collections. The router 10f is a router corresponding to the grandchild of the router 10a.

First, the second calculation unit 213 of the coordinator 20 sets the number of directly connected routers as an initial value of the third remaining collection number (S1). Since the number of routers directly under control of the coordinator 20 is two, that is, the router 10a and the router 10b, the third remaining collection number is 2 at this point.

Next, the third transmission unit 211 transmits a data request to one of the direct routers registered in the connection information database 90b of the storage unit 250 (S2). In the present embodiment, for example, the router 10a is registered in the connection information database 90b first. In this case, the third transmitter 211 first transmits a data request to the router 10a. In this case, the first receiving unit 112 of the router 10a receives the data request transmitted from the coordinator 20.

The second clock unit 214 of the coordinator 20 starts clocking the elapsed time when the third transmitter 211 transmits a data request to the router 10a (S3).

Then, the second transmission unit 116 of the router 10a transmits the reception response to the coordinator 20 (S4).

Further, the third receiving unit 212 of the coordinator 20 receives the reception response from the router 10a. The second timekeeping unit 214 of the coordinator 20 ends the timekeeping of the elapsed time when the third receiving unit 212 receives the reception response from the router 10a (S5).

Next, the first calculation unit 115 of the router 10a sets the number of directly connected routers as an initial value of the first remaining collection number (S6). Since the number of routers directly under the router 10a is two, that is, the router 10c and the router 10d, the first remaining collection number is 2 at this point.

Next, the second transmission unit 116 of the router 10a specifies that the transmission destination of the sensor data is the coordinator 20 based on the parent router or coordinator identification information registered in the connection information database 90a of the storage unit 150. The second transmission unit 116 also reads the sensor data acquired by the acquisition unit 111, that is, the sensor data acquired by the own device, from the storage unit 150. The second transmission unit 116 transmits the sensor data acquired by the own device and the first remaining collection number calculated by the first calculation unit 115 to the coordinator 20 (S7).

The third receiving unit 212 of the coordinator 20 receives the sensor data and the first remaining collection number from the router 10a. The third receiving unit 212 stores the received sensor data in the storage unit 250. Further, the third transmission unit 211 of the coordinator 20 transmits the reception response to the router 10a (S8).

Next, the first transmission unit 113 of the router 10a transmits a data request to one of the direct routers based on the direct router identification information registered in the connection information database 90a (S9).

As described with reference to FIG. 4, since the router 10c is registered first in the connection information database 90a of the router 10a, the first transmission unit 113 first transmits a data request to the router 10c.

The first clock unit 117 of the router 10a starts clocking the elapsed time when the first transmitter 113 sends a data request to the router 10c (S10).

Then, the first receiving unit 112 of the router 10c receives the data request transmitted from the router 10a. The second transmission unit 116 of the router 10c transmits the reception response to the router 10a (S11).

Further, the second receiving unit 114 of the router 10a receives the reception response from the router 10c. When the second receiving unit 114 receives the reception response from the router 10c, the first timing unit 117 of the router 10a ends the counting of the elapsed time (S12). In the example shown in FIG. 6, it is assumed that the elapsed time of the data request from the router 10a to the router 10c is less than the predetermined time, and the data request has not timed out.

Then, the first calculation unit 115 of the router 10c sets the number of directly connected routers as the initial value of the second remaining collection number (S13). Since there is no direct router of the router 10c, the second remaining collection number is zero.

In FIG. 6, since the description is based on the router 10a, the remaining number of collections calculated by the first calculating unit 115 of the router 10a is calculated by the first remaining number of collections, and the first calculating unit 115 of the router 10c calculates. Although the remaining number of collected vehicles is set as the second remaining number of collected vehicles, it is assumed that there is no difference in the method of calculating the first remaining number of collected vehicles and the second remaining number of collected vehicles. When the router 10c is used as a reference, the remaining number of collections calculated by the first calculation unit 115 of the router 10c is the first remaining number of collections.

Next, the second transmission unit 116 of the router 10c transmits to the router 10a the sensor data acquired by the own device and the second remaining collection number calculated by the first calculation unit 115 of the router 10c ( S14).

The second receiving unit 114 of the router 10a receives the sensor data and the second remaining collection number from the router 10c. Then, the second transmission unit 116 of the router 10a transmits the reception response to the router 10c (S15).

Further, the first calculating unit 115 of the router 10a determines that the data collection from the router 10c is completed because the second remaining collection number received by the second receiving unit 114 from the router 10c is 0. In this case, the first calculation unit 115 of the router 10a subtracts the first remaining collection quantity by one (S16). At this point, the first remaining collection number is 1. The first calculation unit 115 stores the first remaining collection number after the subtraction in the storage unit 150.

Next, the second transmission unit 116 of the router 10a transmits the sensor data received from the router 10c and the first remaining collection number after subtraction to the coordinator 20 (S17). Here, when distinguishing the sensor data received by the router 10 from another router 10 from the sensor data acquired by the acquisition unit 111 of the own device, it is referred to as “sensor data of the subordinate router 10”. Further, the transmission of the sensor data of the router 10 under the control of the router 10 to the upper router 10 or the coordinator 20 is also referred to as “relaying the sensor data”.

The third receiving unit 212 of the coordinator 20 receives the sensor data and the first remaining collection number from the router 10a, and stores the received sensor data in the storage unit 250. Further, the third transmission unit 211 transmits a reception response to the router 10a (S18).

In addition, the first transmission unit 113 of the router 10a determines that the data collection from the router 10c is completed because the second remaining collection number received by the second reception unit 114 from the router 10c is 0. Then, the first transmission unit 113 of the router 10a refers to the direct router identification information registered in the connection information database 90a, and transmits a data request to the router 10d registered next to the router 10c (S19). ..

The first clock unit 117 of the router 10a starts clocking the elapsed time when the first transmitter 113 sends a data request to the router 10d (S20).

Then, the first receiving unit 112 of the router 10d receives the data request transmitted from the router 10a. Further, the second transmission unit 116 of the router 10d transmits the reception response to the router 10a (S21).

Further, the second receiving unit 114 of the router 10a receives the reception response from the router 10d. When the second receiver 114 receives the reception response from the router 10d, the first timer 117 of the router 10a ends the elapsed time measurement (S22). It is assumed that the data request from the router 10a to the router 10d has not timed out.

Then, the first calculation unit 115 of the router 10d sets the number of directly connected routers as an initial value of the second remaining collection number (S23). Since there are two routers, the router 10f and the router 10g, which directly report to the router 10d, the second remaining collection quantity is 2 at this point.

Next, the second transmission unit 116 of the router 10d transmits the sensor data acquired by itself and the second remaining collection number to the router 10a (S24).

The second receiving unit 114 of the router 10a receives the sensor data and the second remaining collection number from the router 10d. Then, the second transmission unit 116 of the router 10a transmits the reception response to the router 10d (S25). Since the second remaining collection number transmitted from the router 10d is not 0, the first calculation unit 115 of the router 10a does not change the first remaining collection number. Therefore, the first remaining collection quantity is 1 at this point.

Next, the second transmission unit 116 of the router 10a transmits the sensor data received from the router 10d and the current first collection remaining number to the coordinator 20 (S26).

The third receiving unit 212 of the coordinator 20 receives the sensor data and the first remaining collection number from the router 10a, and stores the received sensor data in the storage unit 250. Further, the third transmission unit 211 transmits the reception response to the router 10a (S27).

Next, the first transmission unit 113 of the router 10d transmits a data request to one of the direct routers based on the direct router identification information registered in the connection information database 90a (S28). In the example of FIG. 6, it is assumed that the first transmission unit 113 of the router 10d first transmits a data request to the router 10f of the direct routers.

The first clock unit 117 of the router 10d starts clocking the elapsed time when the first transmitter 113 sends a data request to the router 10f (S29).

Then, the first receiving unit 112 of the router 10f receives the data request transmitted from the router 10d. Further, the second transmission unit 116 of the router 10f transmits the reception response to the router 10d (S30).

Further, the second receiving unit 114 of the router 10d receives the reception response from the router 10f. When the second reception unit 114 receives the reception response from the router 10f, the first clock unit 117 of the router 10d ends the elapsed time measurement (S31). It is assumed that the data request from the router 10d to the router 10f has not timed out.

Next, the first calculation unit 115 of the router 10f sets the number of directly connected routers as an initial value of the remaining collection number (S32). Since the number of routers directly belonging to the router 10f is 0, the fourth remaining collection number is 0.

Next, the second transmission unit 116 of the router 10f transmits the sensor data acquired by the device itself and the fourth remaining collection number to the router 10d (S33).

The second receiving unit 114 of the router 10d receives the sensor data and the fourth remaining collection number from the router 10f. Then, the second transmission unit 116 of the router 10d transmits the reception response to the router 10f (S34).

Further, the first calculation unit 115 of the router 10d determines that the data collection from the router 10f has been completed because the fourth remaining collection number received by the second reception unit 114 from the router 10f is 0. The second remaining collection number is subtracted by one (S35). At this point, the first remaining collection quantity is 1. The first calculation unit 115 stores the first remaining collection number after the subtraction in the storage unit 150.

Next, the second transmission unit 116 of the router 10d transmits the sensor data received from the router 10f and the second collection remaining number after subtraction to the router 10a (S36).

The second receiving unit 114 of the router 10a receives the sensor data and the second remaining collection number from the router 10d. Then, the second transmission unit 116 of the router 10a transmits the reception response to the router 10d (S37). Since the second remaining collection number transmitted from the router 10d is not 0, the first calculation unit 115 of the router 10a does not change the first remaining collection number. Therefore, the first remaining collection quantity is 1 at this point.

Next, the second transmission unit 116 of the router 10a transmits the sensor data received from the router 10d and the current first remaining collection number to the coordinator 20 (S38).

The third receiving unit 212 of the coordinator 20 receives the sensor data and the first remaining collection number from the router 10a, and stores the received sensor data in the storage unit 250. Further, the third transmission unit 211 transmits the reception response to the router 10a (S39).

Then, the router 10d performs the data collection process also on the router 10g, which is another direct router, in the same manner as the process performed on the router 10f, until the second remaining collection number becomes 0. Perform processing.

When the second remaining collection number calculated by the first calculation unit 115 of the router 10d becomes 0, the second transmission unit 116 of the router 10d receives a message from the subordinate router 10 (in this case, the router 10g). The received sensor data and the second remaining collection number which has become 0 are transmitted to the router 10a (S40).

The second receiving unit 114 of the router 10a receives the sensor data and the second remaining collection number from the router 10d. The second transmission unit 116 of the router 10a transmits a reception response to the router 10d (S41).

Then, the first calculator 115 of the router 10a receives the data from the router 10d and all the routers 10 under the router 10d because the second remaining collection number received by the second receiver 114 from the router 10d is 0. Judge that the collection is completed. In this case, the first calculation unit 115 of the router 10a subtracts the first remaining collection quantity by one (S42). At this time point, the first remaining collection number is zero. Here, the first transmission unit 113 of the router 10a ends the transmission of the data request to the direct router.

Next, the second transmission unit 116 of the router 10a transmits the sensor data received from the router 10d and the first remaining collection number that has become 0 to the coordinator 20 (S43).

The third receiving unit 212 of the coordinator 20 receives the sensor data and the first remaining collection number from the router 10a, and stores the received sensor data in the storage unit 250. Further, the third transmission unit 211 transmits the reception response to the router 10a (S44).

The second calculation unit 213 of the coordinator 20 determines that the data collection from the router 10a is completed because the first remaining collection number received by the third reception unit 212 from the router 10a is 0. Then, the second calculation unit 213 subtracts the third remaining collection quantity by one (S45). At this point, the third remaining collection number is 1.

In addition, the third transmission unit 211 of the coordinator 20 determines that the data collection from the router 10a has been completed because the first remaining collection number received by the third reception unit 212 from the router 10a is 0. Then, the third transmission unit 211 of the coordinator 20 refers to the direct router identification information registered in the connection information database 90b, and transmits a data request to the router 10b registered next to the router 10a (S46). ..

Then, like the router 10a, the router 10b executes the data collection process of the router 10 under its control. When the first remaining collection number of the router 10b becomes 0, the second transmission unit 116 of the router 10b sets the sensor data received from the subordinate router 10 and the first remaining collection number of 0 to It transmits to the coordinator 20 (S47).

The third reception unit 212 of the coordinator 20 receives the sensor data and the first remaining collection number from the router 10b, and stores the received sensor data in the storage unit 250. Further, the third transmission unit 211 transmits the reception response to the router 10b (S48). Then, the third transmission unit 211 of the coordinator 20 ends the transmission of the data request to the direct router.

Then, the communication unit 215 transmits the sensor data to the PC 40 when the third remaining collection number becomes 0 (S49).

Conventionally, for example, in order to prevent the data transmission timing of each router from overlapping, the coordinator may manage the transmission timing of all routers included in the multi-hop network. In such a technique, for example, since the coordinator individually sends a data request to each router included in the multi-hop network, the coordinator has the identification information of all the routers 10 included in the multi-hop network and all the routers 10 included in the multi-hop network. It was necessary to store the route information for reaching the router 10. Since each router relays the data request sent from the coordinator to the target router, each router stores in advance the identification information of all the subordinate routers and the route information for reaching all the subordinate routers. I had to keep it.

On the other hand, when the router 10 of the present embodiment receives a data request from another router 10 or a coordinator 20 located upstream of the router 10 on the multi-hop network, the router 10 directly stored in the storage unit 150. A data request is sent to one of the direct routers based on the identification information of the router, and the sensor data collected from the direct router and the first remaining number of collections are sent to the other router 10 or coordinator 20 of the data request source. To do. Further, the router 10 of the present embodiment transmits a data request to another direct router when the data collection from the direct router is completed and the first remaining number of collection is other than 0.

Therefore, according to the router 10 of the present embodiment, data collection is performed one by one for the direct routers, so that it is possible to reduce duplication of the transmission timing of the sensor data from the direct routers to the router 10. Further, according to the router 10 of the present embodiment, the router 10 is a data request destination even if it does not store the identification information of all the subordinate routers 10 or the route information for reaching all the subordinate routers 10. Since it suffices to store the identification information for specifying the direct router, the amount of data stored in each router 10 can be reduced.

In particular, a wireless communication device used in the field of WSN (Wireless Sensor Network) or IoT is required to be downsized, and thus resources such as a memory may be scarce. Even in such a case, the router 10 of this embodiment can be applied.

Further, in the present embodiment, it is possible to reduce loss of sensor data and improve reliability by reducing the number of routers 10 simultaneously transmitting sensor data to one router 10. it can.

Further, in the above-described conventional technique, the coordinator individually transmits a data request to all routers, and the router under the coordinator relays the data request to the target router. Therefore, in the tree-type network including eight routers as in the example shown in FIG. 1, in order to collect data from all eight routers, the coordinator or the router transmits a total of 17 data requests. It will be. When the number of data request transmissions increases, the risk of data loss due to data request failure may increase. Further, when the router 10 or the coordinator 20 manages the transmission timing of the data request so that the transmission timings do not overlap, the processing time may increase due to the increase in the number of transmissions, and it may take time to collect the sensor data.

On the other hand, when the router 10 of the present embodiment receives a data request from another router 10 or a coordinator 20 located upstream of the router 10 on the multi-hop network, the first collection remaining number is 0. Until that time, the data requests are sequentially transmitted to the direct routers, so that the data can be collected from the subordinate routers 10 without receiving the data requests designating the individual routers 10. Therefore, according to the router 10 of the present embodiment, the number of times the router 10 or the coordinator 20 transmits a data request can be reduced. Specifically, in the multi-hop network of the present embodiment shown in FIG. 1, data can be collected from all eight routers 10 by the same number of eight data requests as the number of routers 10.

Further, according to the router 10 of the present embodiment, the risk of data loss due to the failure of the data request can be reduced by reducing the number of times the data request is transmitted. Therefore, according to the router 10 of the present embodiment, efficient and highly reliable data collection can be realized.

Further, the router 10 of the present embodiment further stores the number of direct routers, and subtracts one from the number of direct routers each time data collection from the direct routers is completed. Calculate the remaining collection number of. Therefore, according to the router 10 of the present embodiment, it is possible to easily specify the number of direct routers for which data collection has not been completed.

Further, the router 10 of the present embodiment receives the sensor data and the second remaining collection number from the direct router, and when the second remaining collection number becomes 0, the data collection from the direct router is completed. I judge that I did. Therefore, according to the router 10 of the present embodiment, whether or not the data collection from the direct router is completed without knowing the total number of routers under the direct router or the route information reaching each router 10. Can be easily determined.

In addition, the router 10 of the present embodiment, if the elapsed time from the transmission of the data request to the direct router to the reception response becomes a predetermined time or more, the router 10 of the first collection remaining number is set to one unit. Subtract and send the first remaining collection number after the subtraction to the upper router 10 or coordinator 20. Therefore, according to the router 10 of this embodiment, sensor data can be efficiently collected from many routers 10 included in the multi-pop network even when the communication connection with the direct router is interrupted. it can.

Further, the router 10 of the present embodiment can efficiently collect the results detected by the sensor 30 in the coordinator 20 by transmitting the sensor data acquired from the sensor 30 to the upper router 10 or the coordinator 20.

Further, the coordinator 20 of the present embodiment sends a data request to one of the direct routers, and when data collection from the direct router is completed, sends the data request to another direct router. Further, the coordinator 20 of the present embodiment ends the transmission of the data request to the direct router when the third remaining collection number becomes 0. Therefore, the coordinator 20 of the present embodiment can reduce simultaneous transmission of sensor data from the plurality of routers 10 to the coordinator 20. Further, since the coordinator 20 need only store the identification information of the direct router which is the destination of the data request, the amount of data stored in the coordinator 20 can be reduced.

According to the wireless communication system S of the present embodiment, by including the router 10 and the coordinator 20 described above, duplication of the transmission timing between the routers 10 is reduced, and the amount of data stored in the router 10 and the coordinator 20 is reduced. It can be reduced.

In the present embodiment, the coordinator 20 performs wired communication with the PC 40, but the coordinator 20 may be a wireless communication compliant with a standard such as 3G (third generation mobile communication system) or LTE (Long Term Evolution). It may be connected to the PC 40 depending on the type. Further, the transmission destination of the sensor data collected by the coordinator 20 is not limited to the PC 40. For example, the coordinator 20 may transmit sensor data to the cloud environment by wireless communication.

Further, in the present embodiment, the elapsed time which is the reference of the timeout is the time from the transmission of the data request to the router 10 or the coordinator 20 direct router to the reception response from the direct router. The standard is not limited to this. For example, a timeout may be set when the elapsed time from transmitting a data request to the router 10 or the coordinator 20 direct router to receiving the sensor data and the remaining number of collections from the direct router is a predetermined time or more. ..

Among the direct routers, the coordinator 20 and the router 10 may retransmit the data request to the router 10 for which the data request has timed out. For example, the router 10 stores in the storage unit 150 the identification information of the direct router for which the data request has timed out, and the direct router for which the data request has timed out after the first remaining collection number becomes 0. The data request may be sent again.

In the present embodiment, the configuration in which the router 10 and the sensor 30 are separate devices has been described, but the router 10 and the sensor 30 may be included in one device.

The program executed by the coordinator 20 or the router 10 of the present embodiment is a file in an installable format or an executable format, and is a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile Disk). , A USB (Universal Serial Bus) memory or the like may be recorded on a computer-readable recording medium and provided, or may be provided or distributed via a network such as the Internet. Also, various programs may be configured to be provided by being pre-installed in a ROM or the like.

The program executed by the router 10 of the present exemplary embodiment includes the above-mentioned functional units (acquisition unit, first receiving unit, first transmitting unit, second receiving unit, first calculating unit, second transmitting unit). Section, the first clock section).

In addition, the program executed by the coordinator 20 of the present embodiment includes the above-described functional units (third transmission unit, third reception unit, second calculation unit, second clock unit, communication unit). It has a modular structure.

In addition, the program for executing the above-described processing in the present embodiment has a module configuration including the above-described functional units, and as actual hardware, for example, a CPU (processor) is a ROM or a flash memory. By reading and executing the program, the above-mentioned functional units are loaded onto the RAM (main memory), and the above-mentioned functional units are generated on the RAM (main memory). It is also possible to realize some or all of the functional units described above using dedicated hardware such as an ASIC (Application Specific Integrated Circuit) and an FPGA (Field-Programmable Gate Array).

In addition, in the present embodiment, the acquisition unit 111, the first reception unit 112, the first transmission unit 113, the second reception unit 114, the first calculation unit 115, the second transmission unit 116, and the first transmission unit 116 of the router 10 are provided. The functions realized by the processor 104 include the first time counting unit 117, the third transmitting unit 221, the third receiving unit 212, the second calculating unit 213, the second time measuring unit 214, and the communication unit 215 of the coordinator 20. However, each functional unit may be realized by a hardware circuit or the like.

While some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are also included in the invention described in the claims and the scope equivalent thereto.

10, 10a to 10h Router 20 Coordinator 30, 30a to 30h Sensor 90a, 90b Connection information database 111 Acquisition unit 112 First reception unit 113 First transmission unit 114 Second reception unit 115 First calculation unit 116 Second Transmitting unit 117 First time measuring unit 150 Storage unit 211 Third transmitting unit 212 Third receiving unit 213 Second calculating unit 214 Second time measuring unit 215 Communication unit 250 Storage unit S Wireless communication system

Claims (7)

A wireless communication device connected to a multi-hop network,
A storage unit that is located downstream of the wireless communication device in the multi-hop network and that stores identification information of one or more first wireless communication devices that are directly connected to the wireless communication device;
A first receiver that receives a data request from a second wireless communication device located upstream of the wireless communication device in the multi-hop network;
A first calculation unit that calculates a first remaining number of collections, which is the number of the first wireless communication devices for which data collection has not been completed;
When the data request is received, the data request is transmitted to one of the first wireless communication devices based on the identification information stored in the storage unit, and the first wireless of the transmission destination is transmitted. When the data collection from the communication device is completed and the first remaining number of collection is other than 0, a data request is transmitted to another one of the first wireless communication devices. 1 transmitter,
A second transmitter that transmits the data collected from the first wireless communication device and the first remaining number of collections to the second wireless communication device;
And a wireless communication device. The storage unit further stores the number of the first wireless communication devices,
The first calculation unit subtracts one unit from the number of the first wireless communication devices stored in the storage unit each time data collection from the first wireless communication device is completed. Calculating the first remaining collection number,
The wireless communication device according to claim 1. From the first wireless communication device, the data and the second remaining collection number, which is the number of uncompleted data collections among the third wireless communication devices directly connected to the first wireless communication device, are received. Further comprising a second receiver,
The first transmission unit determines that data collection from the first wireless communication device is completed when the second remaining collection number is 0.
The wireless communication device according to claim 1. Timekeeping for measuring an elapsed time from when the first transmitting unit transmits a data request to the first wireless communication device to when the second receiving unit receives a reception response from the first wireless communication device More parts,
The first calculation unit subtracts one unit from the first remaining collection number when the elapsed time is equal to or longer than a predetermined time,
The second transmission unit transmits the first remaining collection number after subtraction to the second wireless communication device,
The wireless communication device according to claim 3. The data is sensor data indicating the detection result of the sensor,
Further comprising an acquisition unit for acquiring the sensor data from the sensor,
The second transmission unit transmits the sensor data acquired by the acquisition unit to the second wireless communication device,
The wireless communication device according to any one of claims 1 to 4. A method performed in a wireless communication device connecting to a multi-hop network, the method comprising:
A first receiving step of receiving a data request from a second wireless communication device located upstream of the wireless communication device in the multi-hop network;
Of the one or more first wireless communication devices located downstream of the wireless communication device in the multi-hop network and directly connected to the wireless communication device, the first wireless communication for which data collection is incomplete A first calculation step of calculating a first remaining collection number, which is the number of devices,
When the data request is received, the data request is transmitted to one of the first wireless communication devices based on the identification information of the first wireless communication device stored in the storage unit, and the destination is transmitted. When the data collection from the first wireless communication device is completed and the first remaining number of collection is other than 0, another one of the first wireless communication devices is selected. A first sending step of sending a data request,
A second transmitting step of transmitting the data collected from the first wireless communication device and the first remaining number of collections to the second wireless communication device;
A wireless communication method including. A plurality of wireless communication devices and at least one management device,
Each of the wireless communication devices,
In a multi-hop network including the wireless communication device and the management device, the identification information of one or a plurality of first wireless communication devices located downstream of the wireless communication device and directly connected to the wireless communication device is stored. Storage part,
A first receiver that receives a data request from a second wireless communication device located upstream of the wireless communication device in the multi-hop network;
A first calculation unit that calculates a first remaining number of collections, which is the number of the first wireless communication devices for which data collection has not been completed;
When the data request is received, the data request is transmitted to one of the first wireless communication devices based on the identification information stored in the storage unit, and the first wireless of the transmission destination is transmitted. When the data collection from the communication device is completed and the first remaining number of collection is other than 0, a data request is transmitted to another one of the first wireless communication devices. 1 transmitter,
A second transmitting unit that transmits the data collected from the first wireless communication device and the first remaining number of collections to the second wireless communication device,
The management device is
Among the plurality of wireless communication devices under the control of the management device, the data request is transmitted to one wireless communication device that is directly connected to the management device, and the data collection from the wireless communication device of the transmission destination of the data request is performed. A third transmitter that, when completed, transmits a data request to another wireless communication device that is directly connected to the management device;
A third receiving unit that receives the data and the first remaining collection number from the wireless communication device or the other wireless communication device that is the transmission destination of the data request,
A second calculation unit that calculates a third remaining collection number, which is the number of wireless communication devices for which data collection has not been completed, each time data collection from the wireless communication device is completed;
The third transmission unit ends the transmission of the data request to the wireless communication device when the third remaining collection number becomes 0,
Wireless communication system.

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