WO2023053376A1

WO2023053376A1 - Communication control system, communication control method, and communication device

Info

Publication number: WO2023053376A1
Application number: PCT/JP2021/036223
Authority: WO
Inventors: 剛藤本
Original assignee: 日本電気株式会社
Priority date: 2021-09-30
Filing date: 2021-09-30
Publication date: 2023-04-06

Abstract

A communication control system (30) includes: a communication quality measurement function unit (41) that measures the communication quality of each of communications via a first radio network interface (44) used for communication using a first radio network and a second radio network interface (45) used for communication using a second radio network; an interface selection function unit (42) that selects one of the first radio network interface and the second radio network interface on the basis of the communication quality; and a base station selection function unit (43) that when the first radio network interface is selected by the interface selection function unit, switches base stations to which the second radio network interface is wirelessly connected.

Description

Communication control system, communication control method, and communication device

The present invention relates to a communication control system, a communication control method, and a communication device capable of efficiently switching wireless networks used for communication between mobile bodies and fixed devices.

In recent years, the bandwidth of wide-area wireless communication networks has increased in particular, making it possible to perform large-capacity communication such as video. In addition, self-managed wide-area wireless communication networks (for example, local 5G, etc., hereinafter referred to as L5G) that enable communication only within a limited range by operators other than telecommunications carriers are also being introduced. there is

However, in self-employed wide-area wireless communication networks, the communication quality can be greatly degraded depending on the location of the communication device, and communication at such locations must be supplemented by wireless LAN.

For example, facilities where local 5G networks are installed include factories, etc., and usually multiple access points are installed as wireless LAN access points.

Also, in factories, moving robots (for example, unmanned guided vehicles, hereinafter referred to as AGVs) are used, and it is necessary to monitor the images captured by the robots with a monitoring device. Video communication requires packet transmission at a stable frame rate. For example, even a temporary interruption of communication during execution of an application that displays video can have a significant impact.

On the other hand, techniques for performing communications that combine multiple wireless networks have been proposed. For example, Patent Literature 1 discloses a technique for joint transmission of LTE and WLAN. According to Patent Document 1, downlink user data is transmitted based on the quality of the radio environment where the UE is located.

Also, in a wireless communication device connectable to multiple wireless networks, a technology has been proposed that detects deterioration in communication quality and switches to communication on a different communication network (see Patent Document 2, for example). According to Patent Document 2, the position of a terminal is determined based on communication quality, and handover between base stations is performed within a wireless communication system according to the application being used and the result of the determination.

Japan special table 2015-519792 International publication number WO2008/066086

However, the access point of the wireless LAN also needs to be switched according to the movement of the AVG, and when the access point is switched, the IP address is also changed, and for example, the image of the monitoring device may be interrupted. In

Patent Documents

1 and 2, no consideration is given to the impact on applications due to IP address changes accompanying switching of access points.

One aspect of the present invention has been made in view of the above problems, and an example of its object is to provide a technology capable of efficiently switching wireless networks used for communication between a mobile body and a fixed device. That's what it is.

A communication control system according to one aspect of the present invention provides communication via a first wireless network interface used for communication by a first wireless network and a second wireless network interface used for communication by a second wireless network. a communication quality measuring function unit that measures communication quality respectively; an interface selection function unit that selects either the first wireless network interface or the second wireless network interface based on the communication quality; and the interface selection a base station selection function unit for switching a base station to which the second radio network interface is wirelessly connected when the first radio network interface is selected by the function unit;

A communication control method according to one aspect of the present invention is a method of controlling communication via a first wireless network interface used for communication by a first wireless network and a second wireless network interface used for communication by a second wireless network. respectively measuring communication quality; selecting one of the first wireless network interface and the second wireless network interface based on the communication quality; and selecting the first wireless network interface. Sometimes including switching the base station to which the second wireless network interface is wirelessly connected.

A communication device according to one aspect of the present invention provides communication via a first wireless network interface used for communication by a first wireless network and a second wireless network interface used for communication by a second wireless network. communication quality measuring means for respectively measuring quality; interface selecting means for selecting either the first wireless network interface or the second wireless network interface based on the communication quality; base station selection means for switching a base station to which the second wireless network interface is wirelessly connected when the first wireless network interface is selected;

According to one aspect of the present invention, it is possible to provide a technology capable of efficiently switching wireless networks used for communication between a mobile object and a fixed device.

1 is a block diagram showing a configuration example of a communication control system according to exemplary Embodiment 1 of the present invention; FIG. 4 is a flow chart showing the flow of a communication control method according to exemplary embodiment 1 of the present invention; FIG. 2 is a diagram illustrating a configuration example of an automated guided vehicle (AGV) control system 10 according to exemplary Embodiment 2 of the present invention; FIG. 2 is a diagram illustrating a communicable range of an L5G network and a communicable range of a wireless LAN within a factory site; 3 is a block diagram showing a functional configuration example of a mobile device; FIG. It is a block diagram which shows the functional structural example of a fixing device. 6 is a block diagram showing a functional configuration example of the controller in FIG. 5; FIG. 7 is a block diagram showing a functional configuration example of the controller in FIG. 6; FIG. FIG. 3 is a diagram illustrating an example of setting IP addresses of an external device, a mobile device, a fixed device, and an application processing device; It is a figure explaining RTT measurement. It is a figure explaining the measurement result of RTT. 10 is a flowchart describing an example of communication quality measurement processing; 10 is a flowchart illustrating an example of network interface switching processing by a mobile device; FIG. 4 is an arrow chart schematically illustrating an example of access point switching processing of a mobile device; FIG. FIG. 11 is a flowchart illustrating in detail an example of base station switching processing of the mobile device 32; FIG. FIG. 11 is a flowchart describing a detailed example of address change processing; FIG. FIG. 12 is a block diagram showing a functional configuration example of a mobile device in exemplary embodiment 3; FIG. 11 is a block diagram showing a functional configuration example of a fixing device in exemplary Embodiment 3; FIG. 12 is a flow chart describing an example of roaming processing in exemplary embodiment 4; FIG. 1 is a block diagram showing a configuration example of a communication device according to illustrative Embodiment 1 of the present invention; FIG. 1 is a diagram showing an example of a computer that executes instructions of a program, which is software that implements each function of a mobile device; FIG.

[Exemplary embodiment 1]
A first exemplary embodiment of the invention will now be described in detail with reference to the drawings. This exemplary embodiment is the basis for the exemplary embodiments described later.

<Overview of Communication Control System 30>
Broadly speaking, the communication control system 30 in accordance with the present exemplary embodiment includes an automated guided vehicle that moves within a site and a wireless network that allows the automated guided vehicle to communicate with fixed devices while the automated guided vehicle is moving. It is a system that controls interface switching.

More specifically, the communication control system 30, as an example,
a communication quality measuring function unit for respectively measuring communication quality of communication via a first wireless network interface used for communication by the first wireless network and a second wireless network interface used for communication by the second wireless network; ,
an interface selection function unit that selects either the first wireless network interface or the second wireless network interface based on the communication quality;
a base station selection function unit that switches a base station to which the second wireless network interface wirelessly connects when the first wireless network interface is selected by the interface selection function unit.

<Configuration of Control System 30>
The configuration of a communication control system 30 according to this exemplary embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing a configuration example of the communication control system 30. As shown in FIG. In the figure, each functional block is connected via a network N. FIG. Here, although the specific configuration of the network N does not limit this embodiment, it is a network different from the first wireless network and the second wireless network which will be described later.

The communication control system 30 communicates with fixed devices (not shown) via the first wireless communication network and the second wireless communication network. A fixed device is a device that is fixed and installed in a predetermined place without moving. The fixed device is connected to, for example, an application processing device, which will be described later, and communicates with the communication control system 30 . In the first wireless communications network, communications are conducted through a base station for the first wireless communications network. A second wireless communication network communicates via a base station for the second wireless communication network. Here, it is assumed that there are two or more base stations for the second wireless communication network. A base station for the second wireless communication network may be referred to as an access point.

As an example, the first wireless network is a local 5G (hereinafter referred to as L5G) network, and the second wireless network is a wireless LAN.

As shown in FIG. 1, the communication control system 30 has communication quality measuring means 41, interface selecting means 42, base station selecting means 43, first wireless network interface 44, and second wireless network interface 45. .

The first wireless network interface 44 is a wireless network interface used for communication on the first wireless network, and the second wireless network interface 45 is a wireless network interface used for communication on the second wireless network. That is, a wireless network interface used for communication is provided according to the type of wireless network.

The communication control system 30 communicates with the application processing device connected to the fixed device using the first wireless network interface 44 or the second wireless network interface 45 in order to execute application processing. As an example, the application processing device is composed of a general-purpose computer and executes applications for monitoring and controlling the communication control system 30 .

Communication quality measuring means 41 measures communication quality of communication via a first wireless network interface used for communication by the first wireless network and a second wireless network interface used for communication by the second wireless network. do.

The interface selection means 42 selects either the first wireless network interface or the second wireless network interface based on communication quality.

A second wireless network has access points, which are two or more base stations connected to fixed equipment.

The base station selection means 43 switches the base station to which the second wireless network interface 45 wirelessly connects when the first wireless network interface 44 is selected by the interface selection means 42 .

That is, when the communication control system 30 communicates with the application processing device, communication is performed by the first wireless network via the first wireless network interface 44, the base station, and the gateway. Alternatively, communication is performed by the second wireless network via the second wireless network interface 45, the access point.

Based on the result of the communication quality measurement performed by the communication quality measurement means 41, the interface selection means 42 selects whether to use the first wireless network or the second wireless network.

Communication quality is measured, for example, by measuring RTT (Round Trip Time) via the first wireless network and RTT via the second wireless network. Measurement of RRT is periodically performed between the communication control system 30 and the fixed device, for example.

The interface selection means 42, for example, refers to the result of communication quality measurement and evaluates the communication quality of each wireless network. Then, a wireless network interface corresponding to a wireless network with a higher evaluation is selected as a wireless network interface to be used for communication with the application processing device.

When the first wireless network interface 44 is selected for communication with the application processing device, the base station selection means 43 selects an access point. That is, to which of the two or more access points the second wireless network interface 45 is to be wirelessly connected is selected. Each access point transmits a beacon signal, which is received by the second wireless network interface 45 . The second wireless network interface 45 switches wirelessly connected access points, for example, by selecting access points with higher reception strength.

The communication control system 30 of FIG. 1 may be configured as one device. For example, as shown in FIG. 20, it is possible to configure one communication device 300 in which the functional blocks shown in FIG. 1 are arranged. That is, the communication device 300 has communication quality measuring means 41 , interface selecting means 42 , base station selecting means 43 , first wireless network interface 44 and second wireless network interface 45 . The function of each functional block is as described above.

<Effect of communication control system 30>
As described above, in the communication control system 30 according to this exemplary embodiment, a wireless network to be used for communication of the application processing device is selected based on the measurement result of the communication quality. Therefore, according to the communication control system 30 according to the present exemplary embodiment, it is possible to select a wireless network with higher communication quality from among a plurality of wireless networks and communicate with the application processing device.

Also, in the communication control system 30 according to this exemplary embodiment, the access point is switched when the first wireless network interface 44 is selected for communication with the application processing device. Therefore, according to the communication control system 30 according to this exemplary embodiment, for example, an access point with a higher received signal strength can be selected from among two or more access points. Since the selection of the access point is executed when the first wireless network interface 44 is selected for communication with the application processing device, communication with the application processing device can be prevented from being interrupted.

<Flow of communication control processing by communication control system 30>
The flow of communication control processing according to this exemplary embodiment will be described with reference to FIG. FIG. 2 is a flow chart showing the flow of the communication control method. As shown in the figure, the communication control process includes steps S21 to S23.

The communication control system 30 uses either the first wireless network interface 44 or the second wireless network interface 45 to communicate with the application processing device connected to the fixed device.

In step S21, the communication quality measuring means 41 measures the communication quality through the first wireless network interface used for communication by the first wireless network and the second wireless network interface used for communication by the second wireless network. Measure the quality of each.

At step S22, the interface selection means 42 selects either the first wireless network interface or the second wireless network interface based on the communication quality. Thereby, the wireless network interface used for communication with the application processing device is selected from the first wireless network interface 44 and the second wireless network interface 45 based on the communication quality.

In step S23, the base station selection means 43 switches the access point of the second wireless network to which the second wireless network interface 44 wirelessly connects. This process is executed when the first wireless network interface 44 is selected in step S23.

<Effect of communication control processing>
As described above, in the communication control process according to this exemplary embodiment, a wireless network to be used for communication of the application processing device is selected based on the communication quality measurement result. Therefore, according to the communication control process according to the present exemplary embodiment, it is possible to select a wireless network with higher communication quality from among a plurality of wireless networks and communicate with the application processing device.

Also, when the first wireless network interface 44 is selected for communication with the application processing device, selection of access point selection is performed. Therefore, according to the communication control process according to this exemplary embodiment, for example, an access point with a higher received signal strength can be selected from among two or more access points. Since the selection of the access point is executed when the first wireless network interface 44 is selected for communication with the application processing device, communication with the application processing device can be prevented from being interrupted.

[Exemplary embodiment 2]
A second exemplary embodiment of the invention will now be described in detail with reference to the drawings. Components having the same functions as the components described in the exemplary embodiment 1 are denoted by the same reference numerals, and descriptions thereof are omitted as appropriate.

<Configuration of AGV control system>
FIG. 3 is a diagram illustrating a configuration example of the automatic guided vehicle control system 10 according to this exemplary embodiment. An unmanned guided vehicle is, for example, an autonomous robot, and is also called an AGV (Automated guided vehicle). The automatic guided vehicle control system 10 is hereinafter referred to as the AGV control system 10 .

The AGV control system 10 shown in FIG. 3 includes an AGV 30A. The AGV 30A travels within the premises according to a preset travel route or remote instructions. Here, the premises are, for example, the premises of a factory.

A moving device 32 is mounted on the AGV 30A. An external device 31A is connected to the mobile device 32 . As an example, the external device 31A is a video camera that captures moving images while the AGV is running, and supplies data of the captured moving images to the moving device 32 .

A 5G router 33 is also connected to the mobile device 32 . The 5G router 33 is used to connect to the wide area wireless network via the base station 71 .

Further, the mobile device 32 has a wireless LAN connection function and can be connected to a wireless LAN via the access point 51-1 or the access point 51-2.

Thus, in the AGV control system 10, wireless networks that require different antenna facilities can be used according to purpose.

Note that the moving device 32 and the external device 31A may be integrated with the AGV 30A. That is, the AGV 30A itself may be configured to have the functions of the mobile device 32 and the external device 31A.

The AGV control system 10 also includes an application processing device 62 . As an example, the application processing device 62 is configured by a general-purpose computer and executes an application for monitoring the running of the AGV 30A. In this application, for example, a moving image captured by the external device 31A is displayed, and the operator of the application processing device 62 monitors whether the AGV runs abnormally while viewing the moving image. That is, moving image communication is performed between the AGV 30A and the application processing device. Also, the operator of the application processing device 62 remotely operates the external device 31A as necessary.

The application processing device 62 may be installed, for example, in a control room inside the factory or outside the factory.

The application processing device 62 is connected to the fixed device 60 . The fixed device 60 is installed, for example, in the vicinity of the application processing device 62 and is connected to the application processing device 62 via a wired LAN via the L2 switch 61 .

The fixed device 60 is also connected to the server 80 . The server 80 is installed, for example, in the vicinity of the application processing device 62 and connected to the fixed device 60 by a wired LAN via the L2 switch 61 . As an example, the server 80 stores information about the AGV travel route, power consumption, etc., and remotely operates the AGV as necessary.

The fixed device 60 is connected to the L2 switch 63, to which the access points 51-1 and 51-2 and the 5G gateway 52 are connected.

The access points 51-1 and 51-2 are wireless LAN access points as described above. For example, mobile device 32 may communicate with fixed device 60 via access point 51-1. As a result, the moving image data captured by the external device 31 A is transmitted to the fixed device 60 via the wireless LAN, and further supplied to the application processing device 62 via the L2 switch 61 .

Of course, communication via a wireless LAN via the access point 51-2 is also possible.

In this example, only the access points 51-1 and 51-2 are shown as wireless LAN access points, but more access points may be installed. An access point may also be called an AP.

In addition, the 5G gateway 52 is connected to the L2 switch 63. 5G gateway 52 is used to connect to the wide area wireless network via base station 71 . For example, mobile device 32 may communicate with fixed device 60 via base station 71 . As a result, the moving image data captured by the external device 31A is transmitted to the fixed device 60 via the wide area wireless network, and further supplied to the application processing device 62 via the L2 switch 61. FIG.

Although details will be described later, data transmitted between the external device 31A and the application processing device 62 is encapsulated in a tunnel protocol and transmitted and received.

That is, the external device 31A connected to the mobile device 32 and the application processing device 62 connected to the fixed device 60 can communicate via a wide area wireless network or a wireless LAN. For example, a wide area wireless network may be the first wireless network and a wireless LAN may be the second wireless network.

A wireless LAN is, for example, a wireless LAN conforming to IEEE802.11. Wireless LANs are also referred to as WLANs.

Here, wide area wireless networks are not necessarily limited to those used for communication with remote locations, and include, for example, L5G networks operated by factory operators. An L5G network is a wireless network that uses millimeter waves. Generally, millimeter waves are radio waves of 30 GHz to 300 GHz in terms of frequency, but the millimeter waves mentioned here include radio waves of less than 30 GHz belonging to FR2 (Frequency Range 2).

For example, if the L5G network is the first wireless network and the WLAN is the second wireless network, the first wireless network and the second wireless network use different frequency bands.

In general, L5G networks have a narrower communicable range than wide-area wireless networks provided by telecommunications carriers. In addition, since L5G networks use millimeter waves, it becomes difficult for radio waves to reach them when there are obstacles. Therefore, in communication using L5G, the communication quality may be significantly degraded depending on the position of the AGV, and communication at such a position must be compensated for by the wireless LAN.

FIG. 4 is a diagram explaining the communicable range of the L5G network and the communicable range of the wireless LAN within the factory premises. The figure shows a factory 100 in a plan view. In the site of the factory 100, as an example, the communicable range of the L5G network and the communicable range of the wireless LAN are indicated by circles.

In the approximate center of FIG. 4, the L5G area 111 is indicated by a solid circle as the communicable range of the L5G network. Also, in FIG. 4, the WLAN areas 112-1 to 112-6 are indicated by dotted circles as wireless LAN communicable ranges. The WLAN areas 112-1 to 112-6 are communicable ranges corresponding to different access points. Here, it is assumed that access points 51-1 through 51-6 are installed corresponding to WLAN areas 112-1 through 112-6, respectively.

Furthermore, as shown in the figure, the L5G area 111 and the WLAN areas 112-1 to 112-6 at least partially overlap.

Since the transmission bandwidth of the L5G network is wider than that of the wireless LAN, when the AGV 30A is located in the L5G area 111, the L5G network is preferentially used for communication with the application processing device 62. be. On the other hand, for example, even in the L5G area 111, when the AGV 30A is located in a place where it is difficult for the radio waves of the L5G network to reach due to obstacles placed in the factory 100, communication with the application processing device 62 A wireless LAN is used for communication.

In this way, by laying the L5G network and appropriately installing a wireless LAN access point, the AGV 30A can communicate with the fixed device 60 via the wireless network wherever it is located in the factory 100.

<Configuration of moving device and fixing device>
FIG. 5 is a block diagram showing a functional configuration example of the mobile device 32. As shown in FIG. Note that, as described above, the moving device 32 may be integrated with the AGV 30A. That is, FIG. 5 may be used as a functional configuration example of the AGV 30A.

As shown in FIG. 5, the mobile device 32 is provided with a controller 131 . The controller 131 is a functional block that controls various processes executed by the mobile device 32 .

In addition, the mobile device 32 is provided with a switch 132 . Switch 132 is also referred to as br0. The switch 132 connects the controller 131 and network interfaces 141, 142, and 144, which will be described later.

Furthermore, the mobile device 32 is provided with a WLAN network interface 141 . The WLAN network interface 141 is also referred to as wlan0.

Also, the mobile device 32 is provided with wired LAN network interfaces 142-1 and 142-2. A wired LAN is, for example, Ethernet (registered trademark). Ethernet network interfaces 142-1 and 142-2 are also referred to as eth0 and eth1, respectively. As an example, eth0 is connected to the 5G router 33 and eth1 is connected to the external device 31A.

The Ethernet network interfaces 142-1 and 142-2 are collectively referred to as the Ethernet network interface 142 when there is no particular need to distinguish them.

Furthermore, the mobile device 32 is provided with virtual network interfaces 144-1 and 144-2.

The virtual network interfaces 144-1 and 144-2 are collectively referred to as the virtual network interface 144 when there is no particular need to distinguish between them.

As an example, the mobile device 32 and the fixed device 60 implement a GRE (Generic Routing Encapsulation) network interface. GRE is an L3 (Layer 3) tunneling protocol. The GRE encapsulates an L2 (Layer 2) frame supplied from the external device 31A into an IP packet, and extracts the L2 frame from the IP packet transmitted from the fixed device 60, for example.

The virtual network interfaces 144-1 and 144-2 are network interfaces used when performing encapsulation by GRE. Virtual network interfaces 144-1 and 144-2 are also referred to as gre0 and gre1, respectively.

Note that gre0 and gre1 are logical interfaces, and frames supplied to gre0 and gre1 are encapsulated and sent out from wlan0 or eth0. Here, gre0 is the logical interface corresponding to wlan0, and gre1 is the logical interface corresponding to eth0.

That is, when packets are transmitted via the wireless LAN between the external device 31A and the application processing device 62, gre0 and the controller 131 are connected by br0. On the other hand, when packets are transmitted between the external device 31A and the application processing device 62 via the L5G network, gre1 and the controller 131 are connected by br0.

gre1 and wlan0 in this exemplary embodiment are an example of the second wireless network interface 45 described above with reference to FIG. Also, gre0 and eth0 in this exemplary embodiment are examples of the first wireless network interface 44 described above with reference to FIG.

Note that a tunnel protocol other than GRE may be adopted.

Also, for example, when measuring RTT via a wireless LAN between the mobile device 32 and the fixed device 60, wlan0 and the controller 131 are connected by br0. Furthermore, when measuring RTT via the L5G network between the mobile device 32 and the fixed device 60, eth0 and the controller 131 are connected by br0.

FIG. 6 is a block diagram showing a functional configuration example of the fixing device 60. As shown in FIG. As shown in the figure, the fixing device 60 is provided with a controller 231 . The controller 231 is a functional block that controls various processes executed by the fixing device 60 .

In addition, the fixing device 60 is provided with a switch 232 . Switch 232 is also referred to as br10. The switch 232 connects the controller 231 and network interfaces 242 and 244, which will be described later.

Furthermore, the fixed device 60 is provided with wired LAN (Ethernet) network interfaces 242-1 and 242-2. Ethernet network interfaces 242-1 and 242-2 are also referred to as eth10 and eth11, respectively. As an example, eth10 is connected to L2 switch 63 and eth1 is connected to L2 switch 61 .

The Ethernet network interfaces 242-1 and 242-2 are collectively referred to as the Ethernet network interface 242 when there is no particular need to distinguish them.

In addition, both the fixed device 60 and the mobile device 32 are equipped with GRE network interfaces, and are provided with virtual network interfaces 244-1 and 244-2.

The virtual network interfaces 244-1 and 244-2 are collectively referred to as the virtual network interface 244 when there is no particular need to distinguish between them.

In fixed device 60 , for example, L2 (Layer 2) frames supplied from application processing device 62 are encapsulated into IP packets by GRE, and L2 frames are encapsulated from IP packets transmitted from mobile device 32 . taken out.

The virtual network interfaces 244-1 and 244-2 are network interfaces used when performing encapsulation by GRE. Virtual network interfaces 244-1 and 244-2 are also referred to as gre10 and gre11, respectively.

Note that gre10 and gre11 are logical interfaces, and frames supplied to gre10 and gre11 are encapsulated and sent out from eth10. Here, it is assumed that gre10 is used for transmitting and receiving packets via the wireless LAN, and gre11 is used for transmitting and receiving packets via the L5G network.

That is, when packets are transmitted via the wireless LAN between the external device 31A and the application processing device 62, the gre10 and the controller 231 are connected by br10. On the other hand, when packets are transmitted through the L5G network between the external device 31A and the application processing device 62, gre11 and the controller 231 are connected by br10.

Note that gre10 of the fixed device is assigned the same tunnel protocol identifier as gre0 of the mobile device 32, so that gre10 and gre0 are associated with each other. Further, gre10 and gre0 are associated with each other by assigning the same tunnel protocol identifier as gre1 of the mobile device 32 to gre11 of the fixed device.

Also, for example, when measuring the RTT via the wireless LAN or the RTT via the L5G network between the mobile device 32 and the fixed device 60, the eth10 and the controller 231 are connected by br10.

FIG. 7 is a block diagram showing a functional configuration example of the controller 131 of FIG. As shown in the figure, the controller 131 has an application communication control unit 161, a communication path selection unit 162, an RTT measurement unit 163, a WLAN monitoring control unit 164, an IP address management unit 165, and a communication interface control unit 170. ing.

The application communication control unit 161 communicates with the application processing device 62 connected to the fixed device 60 via the L5G network or WLAN. It controls transmission and reception of packets transmitted between the external device 31A and the application processing device 62 . That is, the application communication control section 161 supplies the data transmitted from the external device 31A to the application processing device 62 to the communication interface control section 170 . Also, the application communication control unit 161 acquires data transmitted from the application processing device 62 to the external device 31A from the communication interface control unit 170 .

Note that the application communication control unit 161 may be provided in the external device 31A.

The RTT measurement unit 163 measures the RTT between the mobile device 32 and the fixed device 60 via the wireless LAN or the RTT via the L5G network. The RTT measurement unit 163 of this exemplary embodiment is an example of the communication quality measurement means 41 described above with reference to FIG. The RTT measurement unit 163 stores the measured RTT as a history of the communication quality of the wireless LAN and the communication quality of the L5G network.

The application communication control unit 161 of this exemplary embodiment is an example of the communication quality measuring means 41 described above with reference to FIG.

The communication path selection unit 162 selects a wireless network interface that the application communication control unit 161 uses for communication with the application processing device 62 . At this time, the communication path selection unit 162 identifies a network interface with more stable communication quality according to changes in the communication quality of the wireless LAN, the communication quality of the wireless LAN of the L5G network, and the communication quality of the L5G network. At this time, either the wireless LAN or the L5G network will be identified.

Then, the communication path selection unit 162 selects the specified network interface as a network interface used for transmitting and receiving packets transmitted between the external device 31A and the application processing device 62. As a result, gre1 or gre0 is switched via the communication interface control unit 170, and is used for transmission/reception of packets transmitted between the external device 31A and the application processing device 62. FIG.

The communication path selector 162 of this exemplary embodiment is an example of the interface selector 42 described above with reference to FIG.

The communication path selection unit 162, for example, generates data for notifying the network interface selected according to a predetermined format, and supplies the data to the communication interface control unit 170. As a result, the fixed device 60 is notified of the selected network interface via the wireless network used for transmission and reception of packets transmitted between the external device 31A and the application processing device 62, for example.

The WLAN monitor control unit 164 measures the strength of signals received from the access points 51-1 to 51-6. That is, the WLAN monitor control unit 164 measures the received signal strength of each access point of the wireless LAN.

Also, when packets transmitted between the external device 31A and the application processing device 62 are transmitted and received via the L5G network, the WLAN monitoring control unit 164 selects an access point to which wlan0 wirelessly connects. For example, while the AGV 30A is running in the L5G area 111, the WLAN monitoring control unit 164 controls selection of the access point to which wlan0 is connected, and selects the access point to which wlan0 is connected via the communication interface control unit 170. switch.

The WLAN supervisory control unit 164 of this exemplary embodiment is an example of the base station selection means 43 described above with reference to FIG.

The IP address management unit 165 controls the assignment of IP addresses to each network interface, and also controls the setting of local addresses and remote addresses used in GRE.

For example, when the access point to which wlan0 is connected is switched, the IP address management unit 165 newly acquires an IP address corresponding to the access point to which wlan0 is switched in accordance with DHCP (Dynamic Host Configuration Protocol) procedures. As a result, the IP address of wlan0 is changed to the newly obtained IP address. Then, the IP address management unit 165 sets the newly acquired IP address as the GRE local address.

Furthermore, the IP address management unit 165 controls notification of the newly acquired IP address to the fixed device 60 . IP address management unit 165 , for example, generates data for IP address notification according to a predetermined format, and supplies the data to communication interface control unit 170 .

As a result, for example, the IP address is notified to the fixed device 60 via the wireless network used for transmitting and receiving packets transmitted between the external device 31A and the application processing device 62. At this time, the IP address is notified together with information specifying the GRE tunnel protocol identifier.

Alternatively, data for notifying the IP address may be stored in the packet used for RTT measurement, and the IP address may be notified to the fixed device 60 .

That is, when the IP address of the wireless network interface is changed, the IP address management unit 165 notifies the fixed device 60 of the changed IP address.

The communication interface control unit 170 controls connections between the network interfaces 141 to 144-2 and the controller 131 by controlling the switch 132 (br0) in FIG.

FIG. 8 is a block diagram showing a functional configuration example of the controller 231 in FIG. As shown in the figure, the controller 231 has an application communication control section 261 , a communication path selection section 262 , an RTT measurement response section 263 , an IP address management section 265 and a communication interface control section 270 .

The application communication control unit 261 controls transmission and reception of packets transmitted between the application processing device 62 and the external device 31A. That is, the application communication control section 261 supplies the communication interface control section 270 with data transmitted from the application processing device 62 to the external device 31A. Also, the application communication control unit 261 acquires data transmitted from the external device 31A to the application processing device 62 from the communication interface control unit 270 .

The RTT measurement response unit 263 transmits an RTT measurement response packet to the RTT measurement unit 163 via the communication interface control unit 270 in response to the RTT measurement packet transmitted from the RTT measurement unit 163 of the mobile device 32 .

When the communication path selection unit 162 of the mobile device 32 notifies the selection of the network interface, the communication path selection unit 262 selects the network interface corresponding to the notified network interface.

The IP address management unit 265 controls the setting of local addresses and remote addresses used in GRE. For example, when the IP address manager 165 of the mobile device 32 notifies the fixed device 60 of the IP address, the IP address manager 265 acquires the tunnel protocol identifier included in the notification. The IP address management unit 265 then identifies the network interface (gre10 or gre11) corresponding to the tunnel protocol ID and changes the remote address.

For example, when gre10 is identified in correspondence with the tunnel protocol identifier, the remote address set in gre10 is changed to the IP address notified from mobile device 32 .

The communication interface control unit 270 controls connections between the network interfaces 241 to 244-2 and the controller 231 by controlling the switch 232 (br10) in FIG.

FIG. 9 is a diagram for explaining an example of setting IP addresses of the external device 31A, the mobile device 32, the fixed device 60, and the application processing device 62. FIG.

In this example, ethX is provided as the Ethernet network interface of the external device 31A, and 192.168.0.2 is set as the IP address.

The IP address 192.168.0.102 is set to br0 of the mobile device 32. The IP address 192.168.20.2 is set to eth0 of the mobile device 32 . The IP address 192.168.10.2 is set to wlan0 of the mobile device 32 .

An IP address of 192.168.20.254 is set on the LAN side of the 5G router 33, and an IP address of 172.16.0.202 is set on the WAN side.

　The IP address 192.168.20.254 is set on the LAN side of the 5G gateway, and the IP address 172.16.0.202 is set on the WAN side.

The IP address 192.168.10.1 for wireless LAN communication and the IP address 192.168.20.1 for L5G network communication are set in eth0 of the fixed device 60 . IP address 192.168.0.101 is set to br0 of the fixed device 60 .

Also, ethY is provided as a network interface for Ethernet of the application processing device 62, and 192.168.0.1 is set as an IP address.

For example, in order for the application processing device 62 to reproduce a moving image captured by the external device 31A almost in real time, the application processing device 62 needs to receive packets of a predetermined IP address without interruption.

That is, the application that monitors the running of the AGV 30A executed by the application processing device 62 needs to be supplied with the moving image data specified by referring to the L3 address (IP address). If the source IP address of the packet in which the data of the moving image is stored is changed during the reproduction of the moving image, it is necessary to make the application recognize the changed IP address again and execute the process of reproducing the moving image again. There is

For example, when the network used for transmitting and receiving packets transmitted between the external device 31A and the application processing device 62 is switched from the L5G network to the wireless LAN, the source IP address of the packet in which the moving image data is stored is changed.

A tunnel protocol is used in order to enable the application processing device 62 to reproduce the moving image captured by the external device 31A in almost real time even if the network is switched in this way. That is, by encapsulating a frame transmitted between the external device 31A and the application processing device 62 with an IP packet and transmitting/receiving it, even if the network is switched, the packet containing the moving image data can be transmitted. It can be transmitted without changing the original IP address.

FIG. 10 is a diagram explaining RTT measurement. An arrow 20A shown in FIG. 10 indicates a communication path of an application that monitors running of the AGV 30A executed by the application processing device 62. FIG. In this example, it is assumed that the communication path selection unit 162 selects a wireless LAN as a wireless network used for transmitting and receiving packets transmitted between the external device 31A and the application processing device 62 .

As shown in FIG. 10, arrow 20A goes from ethX of external device 31A via eth1, br0, gre0, and wlan0 of mobile device 32 to the wireless LAN. Further, the arrow 20A reaches ethY of the application processing device 62 via eth10, gre10, br10, and eth11 of the fixed device 60 . That is, packets are transmitted with the IP address of ethX of the external device 31A and the IP address of ethY of the application processing device 62 as the source IP address and the destination IP address, respectively.

An arrow 20B shown in FIG. 10 indicates the communication path for measuring the RTT of the wireless LAN. As shown in FIG. 10 , arrow 20B is an arrow from wlan0 of mobile device 32 to eth10 of fixed device 60 . That is, in measuring the RTT of the wireless LAN, packets are transmitted with the wlan0 IP address of the mobile device 32 and the eth10 wireless LAN communication IP address of the fixed device 60 as the source IP address and the destination IP address, respectively. will be

An arrow 20C shown in FIG. 10 indicates a communication path for RTT measurement of the L5G network. As shown in FIG. 10 , arrow 20C is an arrow from eth0 of moving device 32 to eth10 of fixed device 60 . That is, in measuring the RTT of the L5G network, packets are transmitted with the eth0 IP address of the mobile device 32 and the eth10 L5G network communication IP address of the fixed device 60 as the source IP address and the destination IP address, respectively. will be

FIG. 11 is a diagram explaining the measurement results of RTT. As described above with reference to FIG. 5, the RTT measurement unit 163 of the mobile device 32 periodically measures the RTT via the wireless LAN or the RTT via the L5G network between the mobile device 32 and the fixed device 60. measure. The RTT measurement unit 163 stores the measured RTT as the communication quality of the wireless LAN and the communication quality of the L5G network.

In FIG. 11, the communication quality of the wireless LAN (WLAN) and the communication quality of the L5G network (L5G) measured by the RTT measurement unit 163 are shown in a table. In this example, the past five RTT measurement results are recorded as the communication quality history. Of course, more RTT measurement results (for example, past 50 times) may be recorded as the communication quality history.

The left column of the table in FIG. 11 shows the time when the communication quality was measured. In this example, communication quality is measured every second.

The center column of the table in FIG. 11 shows the RTT value as the communication quality of the wireless LAN. The right column of the table in FIG. 11 shows the RTT value as the communication quality of the L5G network. Note that it can be determined that the smaller the RTT value, the higher the communication quality of the network.

The communication path selection unit 162 evaluates the communication quality of the wireless LAN and the communication quality of the L5G network shown in FIG. Since the RTT value of the wireless LAN is usually smaller than the RTT value of the L5G network, simply comparing the RTT value of the wireless LAN and the RTT value of the L5G network is not performed.

As an example, when evaluating the communication quality of a wireless LAN, the communication path selection unit 162 acquires RTT values for the past five times. Then, the communication path selection unit 162 determines whether or not each of the two most recent RTT values exceeds the average value of the previous three RTT values by 50% or more. If each of the two most recent RTT values exceeds the average of the previous three RTT values by 50% or more, it is determined that the communication quality of the wireless LAN has deteriorated.

As an example, when evaluating the communication quality of the L5G network, the communication path selection unit 162 acquires the past (most recent) two RTT values. Then, the communication path selection unit 162 determines whether or not each of the two most recent RTT values exceeds a preset threshold. If each of the two most recent RTT values exceeds the threshold, it is determined that the communication quality of the L5G network has deteriorated.

<Flow of communication quality measurement processing>
Next, an example of communication quality measurement processing by the mobile device 32 will be described with reference to the flowchart of FIG.

In step S41, the RTT measurement unit 163 determines whether or not a predetermined time has passed, and waits until it is determined that the predetermined time has passed. The predetermined time is, for example, 1 second. If it is determined in step S41 that the predetermined time has passed, the process proceeds to step S42.

In step S42, the RTT measurement unit 163 measures the RTT of the L5G network. At this time, the RTT of the route indicated by arrow 20C in FIG. 10 is measured.

In step S43, the RTT measurement unit 163 measures the RTT of the wireless LAN. At this time, the RTT of the route indicated by arrow 20B in FIG. 10 is measured.

In step S44, the RTT measurement unit 163 updates the communication quality history. At this time, for example, the communication quality history described with reference to FIG. 11 is updated.

After step S44, the process returns to step S41.

In this way, the communication quality measurement process is executed, and the RTT (communication quality) is measured periodically (for example, at intervals of 1 second). The measurement results are stored as a history of communication quality.

<Flow of network interface switching processing>
Next, an example of network interface switching processing by the mobile device 32 will be described with reference to the flowchart of FIG. Here, the wireless network currently used for transmitting and receiving packets transmitted between the external device 31A and the application processing device 62 will be called a main path network. On the other hand, a wireless network that is currently not used for transmission/reception of packets transmitted between the external device 31A and the application processing device 62 will be referred to as a backup route network.

For example, when packets are currently being transmitted and received between the external device 31A and the application processing device 62 via the L5G network, the L5G network becomes the main route network and the wireless LAN becomes the backup route network. In the following, the network interface switching process will be described assuming that the L5G network is currently the main path network.

In step S61, the communication path selection unit 162 refers to the history of communication quality and evaluates the communication quality of the main path network. At this time, for example, each of the most recent two RTT values of the L5G network is compared with a preset threshold value.

In step S62, the communication path selection unit 162 determines whether or not the communication quality of the main path network has deteriorated. For example, when each of the two most recent RTT values of the L5G network exceeds a preset threshold value, it is determined that the communication quality of the main route network has deteriorated.

If it is determined in step S62 that the communication quality of the main route network has deteriorated, the process proceeds to step S63. At step S63, a wireless network interface to be used for communication with the application processing device 62 is selected. At this time, the communication path selection unit 162 selects a network interface corresponding to the main path network so as to switch the main path network and the backup path network. That is, the wireless network interface is selected according to the stored change in communication quality, and the main route network and the backup route network are switched.

In step S63, the communication path selection unit 162 switches, via the communication interface control unit 170, the network interface used for transmitting and receiving packets transmitted between the external device 31A and the application processing device 62. In the present case, the network interface is switched from gre1 to gre0.

Note that the network interface corresponding to the main route network is stored by br0. Therefore, after this, when packets are transmitted between the external device 31A and the application processing device 62, gre0 and the controller 131 are connected by br0.

In step S64, the communication path selection unit 162 generates data for notification of the selected network interface according to, for example, a predetermined format, and supplies the data to the communication interface control unit 170. As a result, the selected network interface is notified to the fixed device 60 via the wireless LAN, for example.

As a result, the main route switches from the L5G network to the wireless LAN.

On the other hand, if it is determined in step S62 that the communication quality of the main route network has not deteriorated, the processing of steps S63 and S64 is skipped.

In this way, the network interface switching process is executed.

As described above, in the network interface switching process according to this exemplary embodiment, the network interface used for communication on the main route network is switched based on the communication quality measurement result. Therefore, for example, a wireless network with higher communication quality can be selected from the L5G network and the wireless LAN to communicate with the application processing device 62 .

<Flow of base station switching processing>
Next, switching of wireless LAN access points in the mobile device 32 when the main route is the L5G network will be described. FIG. 14 is an arrow chart that schematically illustrates an example of access point switching processing of the mobile device 32 .

First, the external device 31A and the application processing device 62 communicate.

At step M1, the mobile device 32 confirms that the main route is the L5G network.

At step M2, the mobile device 32 confirms that the WLAN is connected to the access point 51-1. Here, access point 51-1 is also referred to as AP1.

At step M3, the mobile device 32 searches for an access point with a stronger signal strength than AP1. A search is also called a search. Here, it is assumed that an access point 51-2 having a stronger signal strength than AP1 is detected as a result of the search. Here, access point 51-2 is also referred to as AP2.

At step M4, the mobile device 32 connects the WLAN to AP2.

At step M5, the mobile device 32 determines whether the WLAN connection destination access point has been changed, and if so, obtains the IP address by DHCP.

At step M6, the mobile device 32 notifies the fixed device 60 of the obtained IP address.

At step F1, the fixed device 60 refers to the IP address notified from the mobile device 32 and changes the remote address of the GRE.

At step M7, the mobile device 32 changes the local address of the GRE.

Next, an example of base station switching processing of the mobile device 32 will be described in detail with reference to the flowchart of FIG.

In step S81, the communication path selection unit 162 determines whether the current main path network is the L5G network. If it is determined that the current main route network is the L5G network, the process proceeds to step S82.

In step S82, the WLAN monitor control unit 164 identifies the access point of the backup route network. Here, an access point is also called an AP. At this time, the AP to which the wireless LAN that is the current backup route network is connected, that is, the AP to which wlan0 is currently wirelessly connected is specified. Here, it is assumed that the AP 51-1 is specified as the AP to which the wireless LAN is connected.

In step S83, the WLAN monitoring control unit 164 measures the received signal strength of the AP. At this time, the received signal strength of each AP connectable at the current position of the AGV is measured. At this time, for example, the received signal strengths of AP51-1 and AP51-2 are measured as the received signal strengths of APs connectable to wlan0.

In step S84, the WLAN monitoring control unit 164 determines whether or not there is an AP whose received signal strength is greater than that of the AP on the backup path. If it is determined in step S84 that there is no AP with a higher received signal strength than the AP on the backup path, the process returns to step S83. If it is determined in step S84 that there is an AP whose received signal strength is greater than that of the AP on the backup path, the process proceeds to step S85.

In step S85, the WLAN monitoring control unit 164 switches the AP on the backup path to an AP with a higher received signal strength. That is, it is determined that the received signal strength of AP51-2 is greater than the received signal strength of AP51-1, and the AP to which wlan0 wirelessly connects is switched to AP51-2.

In step S86, the IP address management unit 165 executes address change processing.

Note that if it is determined in step S81 that the current main path network is not the L5G network, the processing of steps S82 to S86 is skipped.

In this way, the base station switching process is executed.

Next, a detailed example of the address change processing in step S86 of FIG. 15 will be described with reference to the flowchart of FIG.

In step S101, the IP address management unit 165 determines whether or not the AP to which the wireless LAN is connected has been changed. For example, when the ESSID (Extended Service Set Identifier) of the AP to which wlan0 is wirelessly connected is changed, it is determined that the AP to which the wireless LAN is connected has been changed. Alternatively, if the wireless LAN RTT measurement fails a predetermined number of times in succession, it may be determined that the AP to which the wireless LAN is connected has been changed.

If it is determined in step S101 that the AP to which the wireless LAN is connected has been changed, the process proceeds to step S102.

In step S102, the IP address management unit 165 acquires the IP address corresponding to the changed connection destination AP. The IP address management unit 165 newly acquires an IP address corresponding to the access point of the switching destination, for example, according to the DHCP procedure. As a result, the IP address of wlan0 is changed to the newly obtained IP address.

In step S103, the IP address management unit 165 transmits and notifies the fixed device 60 of the changed IP address. IP address management unit 165 , for example, generates data for IP address notification according to a predetermined format, and supplies the data to communication interface control unit 170 .

As a result, for example, the IP address is notified to the fixed device 60 via the main path network. Alternatively, data for notifying the IP address may be stored in the packet used for RTT measurement, and the IP address may be notified to the fixed device 60 .

At this time, the IP address is notified along with information specifying the GRE tunnel protocol identifier. In fixed device 60, IP address management unit 265 identifies the network interface corresponding to the tunnel protocol identifier and changes the remote address.

In step S104, the IP address management unit 165 changes the local address. As a result, the newly obtained IP address is set as the GRE local address.

In this way, the address change process is executed.

As described above, according to the base station switching process of this exemplary embodiment, access point switching is performed when the main route network is the L5G network. As a result, for example, an access point with a higher received signal strength can be detected from among two or more access points, and wireless connection switching can be executed. Also, switching of the access point to be connected to is executed when the main route network is the L5G network, so communication with the application processing device 62 can be prevented from being interrupted.

[Exemplary embodiment 3]
A third exemplary embodiment of the invention will now be described in detail with reference to the drawings. Components having the same functions as those described in Exemplary Embodiment 1 or Exemplary Embodiment 2 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

In exemplary embodiment 2, only wlan0 is provided as a wireless LAN network interface, but in this exemplary embodiment, another wireless LAN network interface is provided.

FIG. 17 is a block diagram showing a functional configuration example of the mobile device 32 in this exemplary embodiment. The figure differs from the functional configuration example shown in FIG. 5 in that a wireless LAN network interface 141-2 and a virtual network interface 144-3 are provided. The wireless LAN network interface 141-2 is also called wlan1. Virtual network interface 144-3 is also referred to as gre2.

gre2 is a logical interface corresponding to wlan1.

FIG. 18 is a block diagram showing a functional configuration example of the fixing device 60 in this exemplary embodiment. This figure differs from the functional configuration example shown in FIG. 6 in that a virtual network interface 244-3 is provided. The virtual network interface 244-3 is also called gre12.

By attaching the same tunnel protocol identifier as gre2 of the mobile device 32 to gre12 of the fixed device, gre12 and gre2 are associated with each other. That is, data transmitted/received via wlan1 of the mobile device 32 is transferred to the controller 131 of the mobile device 32 via gre2, and transferred to the controller 231 of the fixed device 60 via gre12.

Here, the WLAN monitoring control unit 164 selects an AP so that the AP to which wlan1 is connected is different from the AP to which wlan0 is wirelessly connected. By doing so, it is possible to prepare two wireless LAN paths.

For example, communication can be performed through two routes, a wireless LAN via AP51-1 and a wireless LAN via AP51-2. In this case, one of the two wireless LAN routes is a priority route and the other is a non-priority route. correspond. For example, gre0 is associated with the priority route and gre2 is associated with the non-priority route.

In this case, in the base station switching process of FIG. 15, in step S84, it is determined whether or not there is an AP with a higher received signal strength than the AP on the priority path. In step S85, the connection destination AP of the non-priority route is switched to the AP with the higher received signal strength. After the processing of step S86 is completed, gre2 is changed to the network interface corresponding to the priority route, and gre0 is changed to the network interface corresponding to the non-priority route.

Also, in this case, in step S63 of FIG. 13, if the backup route network is a wireless LAN, the network interface associated with the priority route is preferentially selected as the network interface of the main route.

By doing so, it is possible to ensure that communication with the application processing device 62 is not interrupted when switching the main path network from L5G to the wireless LAN.

That is, the change of the IP address due to the switching of the access point is performed only for the network interface of the non-priority route, and the change of the priority route and the non-priority route is not performed until the base station switching process is completed. Therefore, even if the main path network is switched from L5G to wireless LAN during execution of the base station switching process, communication with the application processing device 62 can be prevented from being interrupted.

Furthermore, by preparing two wireless LAN paths, even if the AGV 30A is located outside the communicable range of the L5G network, communication with the application processing device 62 can be performed by switching the wireless LAN access point. Quality can be improved.

[Exemplary embodiment 4]
A fourth exemplary embodiment of the invention will now be described in detail with reference to the drawings. Components having the same functions as those described in Exemplary Embodiment 1 or Exemplary Embodiment 2 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

In this exemplary embodiment, a case where wide area wireless network roaming is possible within the premises of a factory will be described. For example, it is assumed that there is a wide area wireless network (hereinafter referred to as W5G network) operated by a telecommunications carrier other than the L5G network in the premises of the factory. Alternatively, a wide area wireless network operated by a carrier other than the L5G network may be the network used to communicate with the fixed device 60 when the AGV is outside the factory.

In this case, roaming may occur while the AGV is communicating using the wide area wireless network.

FIG. 19 is a flowchart describing an example of roaming processing in this exemplary embodiment.

In step S121, the communication path selection unit 162 of the mobile device 32 determines whether or not the wide area network in which the 5G router 33 is located has been changed. The communication path selection unit 162, for example, acquires information related to the wide area network currently in service from the 5G router 33, and confirms whether or not the change has been made. Alternatively, if the RTT measurement fails a predetermined number of times in succession, it may be determined that the change has occurred.

If it is determined in step S121 that the wide area network in which the 5G router 33 is located has been changed, the process proceeds to step S122.

In step S123, the IP address management unit 165 determines whether or not the IP address has been changed. At this time, for example, it is determined whether or not the WAN-side address of the 5G router has been changed. If it is determined in step S123 that the IP address has been changed, the process proceeds to step S123.

In step S123, the IP address management unit 165 transmits and notifies the fixed device 60 of the changed IP address. IP address management unit 165 , for example, generates data for IP address notification according to a predetermined format, and supplies the data to communication interface control unit 170 .

As a result, for example, the IP address is notified to the fixed device 60 via the main route network. Alternatively, data for notifying the IP address may be stored in the packet used for RTT measurement, and the IP address may be notified to the fixed device 60 .

In step S124, the IP address management unit 165 changes the local address. As a result, the changed IP address is set as the GRE local address.

In this way, the roaming process is executed. Note that the roaming process may be executed when the main route network is a wireless LAN.

Thus, according to this exemplary embodiment, even if roaming occurs in the wide area wireless network, it is possible to perform communication using the tunnel protocol.

[Example of realization by software]
Some or all of the functions of the mobile device 32 may be implemented by hardware such as an integrated circuit (IC chip), or may be implemented by software.

In the latter case, the mobile device 32 is realized, for example, by a computer that executes instructions of a program, which is software that realizes each function. An example of such a computer (hereinafter referred to as computer C) is shown in FIG.

Computer C includes at least one processor C1 and at least one memory C2. A program P for operating the computer C as the mobile device 32 is recorded in the memory C2. In the computer C, the processor C1 reads the program P from the memory C2 and executes it, thereby realizing each function of the mobile device 32 .

As the processor C1, for example, CPU (Central Processing Unit), GPU (Graphic Processing Unit), DSP (Digital Signal Processor), MPU (Micro Processing Unit), FPU (Floating point number Processing Unit), PPU (Physics Processing Unit) , a microcontroller, or a combination thereof. As the memory C2, for example, a flash memory, HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof can be used.

Note that the computer C may further include a RAM (Random Access Memory) for expanding the program P during execution and temporarily storing various data. Computer C may further include a communication interface for sending and receiving data to and from other devices. Computer C may further include an input/output interface for connecting input/output devices such as a keyboard, mouse, display, and printer.

In addition, the program P can be recorded on a non-temporary tangible recording medium M that is readable by the computer C. As such a recording medium M, for example, a tape, disk, card, semiconductor memory, programmable logic circuit, or the like can be used. The computer C can acquire the program P via such a recording medium M. Also, the program P can be transmitted via a transmission medium. As such a transmission medium, for example, a communication network or broadcast waves can be used. Computer C can also obtain program P via such a transmission medium.

[Appendix 1]
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. For example, embodiments obtained by appropriately combining the technical means disclosed in the embodiments described above are also included in the technical scope of the present invention.

[Appendix 2]
Some or all of the above-described embodiments may also be described as follows. However, the present invention is not limited to the embodiments described below.

(Appendix 1)
a communication quality measuring function unit for respectively measuring communication quality of communication via a first wireless network interface used for communication by the first wireless network and a second wireless network interface used for communication by the second wireless network; ,
an interface selection function unit that selects either the first wireless network interface or the second wireless network interface based on the communication quality;
a base station selection function unit that switches a base station to which the second wireless network interface wirelessly connects when the first wireless network interface is selected by the interface selection function unit. control system.

According to the above configuration, it is possible to efficiently switch the wireless network used for communication between the mobile object and the fixed device.

(Appendix 2)
further comprising an application processing function unit that communicates with the application processing device,
The interface selection function unit selects a wireless network interface used by the application processing function unit for communication with the application processing device,
The application processing function unit communicates with the application processing device via a fixed device connected to the application processing device,
further comprising an address control function unit that, when the IP address of the wireless network interface is changed, notifies the fixed device of the changed IP address;
The communication control system according to appendix 1, characterized by:

According to the above configuration, it is possible to support communication using tunnel protocols on multiple wireless networks.

(Appendix 3)
The communication control system according to appendix 1, wherein the first wireless network and the second wireless network use different frequency bands.

According to the above configuration, wireless networks with different antenna facilities can be efficiently used according to the purpose.

(Appendix 4)
The first wireless network is a wireless network using millimeter waves,
The communication control system according to appendix 3, wherein the second wireless network is a wireless LAN.

According to the above configuration, wireless communication using the L5G network is possible.

(Appendix 5)
5. The communication control system according to appendix 3 or 4, wherein the communicable ranges of the first and second wireless networks overlap at least partially.

According to the above configuration, it is possible to enable communication throughout the factory premises due to the communication ranges of multiple wireless networks.

(Appendix 6)
The communication quality measurement function unit stores the measured communication quality,
6. The communication control system according to any one of appendices 1 to 5, wherein the interface selection function unit selects the wireless network interface according to the stored change in communication quality.

According to the above configuration, it is possible to more properly evaluate the quality of a plurality of different wireless networks.

(Appendix 7)
7. The communication control system according to any one of appendices 1 to 6, wherein moving image communication is performed via the wireless network interface function unit selected by the interface selection function unit.

According to the above configuration, it is possible to transmit a moving image used for monitoring a moving object, for example.

(Appendix 8)
Measuring communication quality of communication via a first wireless network interface used for communication by the first wireless network and a second wireless network interface used for communication by the second wireless network, respectively;
selecting either the first wireless network interface or the second wireless network interface based on the communication quality;
A communication control method, comprising switching a base station to which the second wireless network interface wirelessly connects when the first wireless network interface is selected.

(Appendix 9)
further comprising communicating with the application processing device;
selecting a wireless network interface for communication with the application processing device;
communicating with the application processing device via a fixed device connected to the application processing device;
further comprising, if the IP address of the wireless network interface has changed, notifying the fixed device of the changed IP address;
The communication control method according to appendix 8, characterized by:

(Appendix 10)
The communication control method according to appendix 8, wherein the first wireless network and the second wireless network use different frequency bands.

(Appendix 11)
The first wireless network is a wireless network using millimeter waves,
11. The communication control method according to appendix 10, wherein the second wireless network is a wireless LAN.

(Appendix 12)
12. The communication control method according to any one of appendices 10 and 11, wherein the communicable ranges of the first and second wireless networks overlap at least partially.

(Appendix 13)
Measured communication quality is stored,
13. The communication control method according to any one of appendices 8 to 12, wherein the wireless network interface is selected according to the stored change in communication quality.

(Appendix 14)
14. The communication control system according to any one of appendices 8 to 13, wherein moving image communication is performed via the selected wireless network interface.

(Appendix 15)
communication quality measuring means for respectively measuring communication quality of communication via a first wireless network interface used for communication by the first wireless network and a second wireless network interface used for communication by the second wireless network;
interface selection means for selecting either the first wireless network interface or the second wireless network interface based on the communication quality;
Base station selection means for switching a base station to which the second wireless network interface is wirelessly connected when the first wireless network interface is selected by the interface selection means. It is possible to efficiently switch the wireless network used for communication between the vehicle and the stationary device.

(Appendix 16)
further comprising application processing means for communicating with the application processing device;
the interface selection means selects a wireless network interface used by the application processing means for communication with the application processing device;
The application processing means communicates with the application processing device via a fixed device connected to the application processing device,
16. The communication device according to claim 15, further comprising address control means for notifying the fixed device of the changed IP address when the IP address of the wireless network interface is changed.

(Appendix 17)
16. The communication device according to appendix 15, wherein the first wireless network and the second wireless network use different frequency bands.

(Appendix 18)
The first wireless network is a wireless network using millimeter waves,
18. The communication device according to appendix 17, wherein the second wireless network is a wireless LAN.

(Appendix 19)
19. The communication device according to any one of appendices 17 and 18, wherein the communicable ranges of the first and second wireless networks overlap at least partially.

(Appendix 20)
The communication quality measuring means stores the measured communication quality,
20. The communication apparatus according to any one of appendices 15 to 19, wherein the interface selection means selects the wireless network interface according to the stored change in communication quality.

(Appendix 21)
21. The communication device according to any one of appendices 15 to 20, wherein moving image communication is performed via the wireless network interface selected by the interface selection means.

[Appendix 3]
Some or all of the embodiments described above can also be expressed as follows.

at least one processor, said processor comprising:
a process of measuring communication quality of communication via a first wireless network interface used for communication by the first wireless network and a second wireless network interface used for communication by the second wireless network;
a process of selecting either the first wireless network interface or the second wireless network interface based on the communication quality;
and switching a base station to which the second wireless network interface wirelessly connects when the first wireless network interface is selected.

The communication control device may further include a memory, in which processing for controlling connection to the wireless network, processing for measuring communication quality of each of the plurality of wireless networks, and processing for measuring communication quality of each of the plurality of wireless networks; A program may be stored for causing the processor to execute a process of selecting a wireless network interface and a process of selecting the base station. Also, this program may be recorded in a computer-readable non-temporary tangible recording medium.

10 AGV control system 30 communication control system 30A AGV
31A external device 32 mobile device 33 5G router 51-1, 51-2 access point 52 5G gateway 60 fixed device 62 application processing device 71 base station 131 controller 132 switch 141, 142, 144 network interface 161 application communication control unit 162 communication path Selection unit 163 RTT measurement unit 164 WLAN monitoring control unit 165 IP address management unit 170 Communication interface control unit 231 Controller 232 Switches 241, 244 Network interface 261 Application communication control unit 262 Communication path selection unit 263 RTT measurement response unit 265 IP address management unit 270 communication interface control unit 300 communication device

Claims

a communication quality measuring function unit for respectively measuring communication quality of communication via a first wireless network interface used for communication by the first wireless network and a second wireless network interface used for communication by the second wireless network; ,
an interface selection function unit that selects either the first wireless network interface or the second wireless network interface based on the communication quality;
a base station selection function unit that switches a base station to which the second wireless network interface wirelessly connects when the first wireless network interface is selected by the interface selection function unit. control system.
further comprising an application processing function unit that communicates with the application processing device,
The interface selection function unit selects a wireless network interface used by the application processing function unit for communication with the application processing device,
The application processing function unit communicates with the application processing device via a fixed device connected to the application processing device,
further comprising an address control function unit that, when the IP address of the wireless network interface is changed, notifies the fixed device of the changed IP address;
The communication control system according to claim 1, characterized by:
The communication control system according to claim 1, wherein the first wireless network and the second wireless network use different frequency bands.
The first wireless network is a wireless network using millimeter waves,
4. The communication control system according to claim 3, wherein said second wireless network is a wireless LAN.
5. The communication control system according to claim 3, wherein the communicable ranges of the first and second wireless networks overlap at least partially.
The communication quality measurement function unit stores the measured communication quality,
6. The communication control system according to any one of claims 1 to 5, wherein the interface selection function unit selects the wireless network interface according to the stored change in communication quality.
7. The communication control system according to any one of claims 1 to 6, wherein moving image communication is performed via the wireless network interface selected by the interface selection function unit.
Measuring communication quality of communication via a first wireless network interface used for communication by the first wireless network and a second wireless network interface used for communication by the second wireless network, respectively;
selecting either the first wireless network interface or the second wireless network interface based on the communication quality;
A communication control method, comprising switching a base station to which the second wireless network interface wirelessly connects when the first wireless network interface is selected.
further comprising communicating with the application processing device;
selecting a wireless network interface for communication with the application processing device;
communicating with the application processing device via a fixed device connected to the application processing device;
further comprising, if the IP address of the wireless network interface has changed, notifying the fixed device of the changed IP address;
9. The communication control method according to claim 8, characterized by:
The communication control method according to claim 8, wherein the first wireless network and the second wireless network use different frequency bands.
The first wireless network is a wireless network using millimeter waves,
The communication control method according to claim 10, wherein said second wireless network is a wireless LAN.
12. The communication control method according to claim 10, wherein the communicable ranges of the first and second wireless networks overlap at least partially.
Measured communication quality is stored,
13. The communication control method according to any one of claims 8 to 12, wherein said wireless network interface is selected according to said stored change in communication quality.
14. The communication control method according to any one of claims 8 to 13, wherein moving image communication is performed via the selected wireless network interface.
communication quality measuring means for respectively measuring communication quality of communication via a first wireless network interface used for communication by the first wireless network and a second wireless network interface used for communication by the second wireless network;
interface selection means for selecting either the first wireless network interface or the second wireless network interface based on the communication quality;
a base station selection unit that switches a base station to which the second wireless network interface wirelessly connects when the first wireless network interface is selected by the interface selection unit.
further comprising application processing means for communicating with the application processing device;
the interface selection means selects a wireless network interface used by the application processing means for communication with the application processing device;
The application processing means communicates with the application processing device via a fixed device connected to the application processing device,
16. The communication device according to claim 15, further comprising address control means for notifying said fixed device of the changed IP address when the IP address of said wireless network interface is changed.
The communication device according to claim 15, wherein the first wireless network and the second wireless network use different frequency bands.
The first wireless network is a wireless network using millimeter waves,
18. The communication device according to claim 17, wherein said second wireless network is a wireless LAN.
19. The communication device according to claim 17 or 18, wherein the communicable ranges of the first and second wireless networks overlap at least partially.
The communication quality measuring means stores the measured communication quality,
20. The communication device according to any one of claims 15 to 19, wherein said interface selection means selects said wireless network interface according to said stored change in communication quality.
21. The communication device according to any one of claims 15 to 20, wherein moving image communication is performed via said wireless network interface selected by said interface selection means.