Communication relay system and communication relay device

Abstract

To keep down the communication bandwidth within a wireless network in a communication relay system that transmits data using the wireless network connecting two networks.SOLUTION: A communication relay system 100 includes communication relay devices 121, 122 in which either an active system or a standby system is set, and communication relay devices 123, 124 in which either an active system or a standby system is set, which relay data between an in-vehicle network 20 and wireless networks 301 and 302. The communication relay device 121 in which the active system is set relays data received from the in-vehicle network 20 to the wireless networks 301 and 302, and the communication relay device 122 in which the standby system is set does not relay the data received from the in-vehicle network 20 to the wireless networks 301 and 302.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a communication relay system and a communication relay device. [Background technology]

[0002] With the advent of the 5th generation mobile communication system (5G), wireless communication has become capable of large-capacity, low-latency transmission, and its use in controlling vehicles such as automobiles and trains is being considered. In addition, by utilizing the public network lines of mobile communication carriers, there is an advantage in that costs for building and maintaining one's own dedicated lines can be reduced.

[0003] However, when wireless communication is used to control vehicles, wireless networks have a narrower communication bandwidth than wired networks, and congestion can cause packet loss or delays, which can make it impossible to control the vehicles. Conventionally, a method of duplicating wireless networks has been used to increase the reliability of communication.

[0004] Patent document 1 describes a duplex device that performs "processing to match information between a new operation device and a standby device when a failure occurs in the operation device and the standby device is switched to a new operation device (when duplex switching occurs)." [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2001-014181 A Summary of the Invention [Problem to be solved by the invention]

[0006] The duplex device described in the above-mentioned Patent Document 1 is a device that performs duplex control from a higher-level device to a lower-level device, and there is no description of redundant control of a wireless network in Patent Document 1. For this reason, the technology described in Patent Document 1 cannot be applied to a vehicle control system that uses a wireless network.

[0007] The present invention has been made in view of the above circumstances, and has an object to provide a communication relay system and a communication relay device that suppress the communication band within a wireless network. [Means for solving the problem]

[0008] A communication relay system according to the present invention relays data transmitted and received between a first network and a second network via a first wireless network and a second wireless network. The communication relay system includes an executive system or The communication system includes a first network, and two first communication relay devices configured as either an active system or a standby system for relaying data between the first wireless network and a second wireless network, and a second network, and two second communication relay devices configured as either an active system or a standby system for relaying data between the first wireless network and the second wireless network to the second network. The first communication relay device of the active system relays data received from the first network to the first wireless network and the second wireless network, the first communication relay device of the standby system does not relay data received from the first network to the first wireless network and the second wireless network, the second communication relay device of the active system relays data received from the first wireless network and the second wireless network to the second network, and the second communication relay device of the standby system does not relay data received from the first wireless network and the second wireless network to the second network. Effect of the Invention

[0009] According to the present invention, only the active communication relay device relays data to the first wireless network and the second wireless network in a duplicated manner, so that the communication band within the wireless network can be reduced. Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing an example of the overall configuration of a conventional communication relay system. [Diagram 2]1 is a block diagram showing a configuration example of a duplicated communication relay system according to an embodiment of the present invention; [Diagram 3] 2 is a block diagram showing an example of an internal configuration of a communication relay device according to an embodiment of the present invention; [Figure 4] FIG. 2 is a block diagram showing an example of the hardware configuration of a computer according to an embodiment of the present invention. [Diagram 5] FIG. 2 is a block diagram showing an example of a data flow during normal operation according to an embodiment of the present invention. [Figure 6] 5 is a sequence diagram showing an example of operation of each device in the communication relay system during normal operation according to an embodiment of the present invention. FIG. [Figure 7] 10 is a sequence diagram showing an example of the operation of each device in the communication relay system when a failure occurs in the communication relay device according to one embodiment of the present invention. FIG. [Figure 8] 10 is a sequence diagram showing an example of the operation of each device in the communication relay system when a failure occurs in a communication relay device that is an execution system in one embodiment of the present invention. FIG. [Figure 9] 10 is a sequence diagram showing an example of the operation of each device in the communication relay system when a failure in the communication relay device according to an embodiment of the present invention is recovered. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functions or configurations are designated by the same reference numerals, and redundant description will be omitted.

[0012] <Example of a conventional communication relay system configuration> First, a configuration example of a conventional communication relay system 10 will be described with reference to FIG. 1 is a block diagram showing an example of the overall configuration of a conventional communication relay system 10. The conventional communication relay system 10 is configured by duplexing general wireless networks.

[0013] The communication relay system 10 is composed of an in-vehicle network 20, a base station network 30, wireless terminals 111, 112, 113, and 114, and wireless networks 301 and 302.

[0014] The in-vehicle network 20 is a network in a single vehicle (not shown). The vehicle in which the in-vehicle network 20 is established is assumed to be a single automobile or a railway train with multiple cars. The blocks in the in-vehicle network 20 are information processing devices such as a personal computer (PC) or an electronic control unit (ECU). The in-vehicle network 20 includes a gateway 101 and a gateway 102 connected to wireless terminals 111 and 112.

[0015] The gateway 101 and the gateway 102 are connected to a wireless terminal 111 and a wireless terminal 112. It is assumed that the wireless terminal 111 and the wireless terminal 112 are both access points. In FIG. 1, the wireless terminal 111 and the wireless terminal 112 are depicted at positions away from the in-vehicle network 20, but in reality, the wireless terminal 111 and the wireless terminal 112 are configured to be included in the in-vehicle network 20.

[0016] The base station network 30 is a network constructed within one control station. The control station manages, for example, the current position and destination of a vehicle. The blocks within the base station network 30 are information processing devices such as a PC or a control console. The base station network 30 includes a gateway 103 and a gateway 104 connected to wireless terminals 113 and 114.

[0017] The gateway 103 and the gateway 104 are connected to a wireless terminal 113 and a wireless terminal 114. It is assumed that the wireless terminal 113 and the wireless terminal 114 are both access points. In FIG. 1, the wireless terminal 113 and the wireless terminal 114 are depicted at positions away from the in-vehicle network 20, but in reality, the wireless terminal 113 and the wireless terminal 114 are configured to be included in the in-vehicle network 20.

[0018] The wireless terminals 111 and 113 are connected to a wireless network 301, and wireless communication is possible between the wireless terminals 111 and 113. The wireless terminals 112 and 114 are connected to a wireless network 302, and wireless communication is possible between the wireless terminals 112 and 114. The wireless networks 301 and 302 may be provided by the same mobile communication carrier, or may be provided by different mobile communication carriers.

[0019] The conventional communication relay system 10 shown in Fig. 1 has a configuration in which the gateway, wireless terminal, and wireless network are duplicated. Therefore, in the conventional communication relay system 10, data communication is not interrupted even if a failure occurs at any point.

[0020] However, in the configuration of the conventional communication relay system 10 shown in Fig. 1, the same signal is transmitted from each gateway to multiple wireless networks (wireless network 301 and wireless network 302). In other words, the same signal is transmitted twice from different gateways to one wireless network. Therefore, compared to a configuration in which each device is not duplicated, twice as many signals are transmitted to one wireless network. As a result, the communication bands of the wireless networks 301 and 302 are strained, and communication costs are also increased.

[0021] [One embodiment] <Configuration example of communication relay system according to the present embodiment> Next, a configuration example of the communication relay system 100 according to an embodiment of the present invention will be described. 2 is a block diagram showing an example of the configuration of a duplicated communication relay system 100 according to an embodiment. In the communication relay system 100, a general wireless network is also configured in a duplicated manner.

[0022] The communication relay system 100 has a function of relaying data transmitted and received between the in-vehicle network 20 and the base station network 30 via the wireless networks 301 and 302. In the communication relay system 100, networks and devices common to those in FIG. 1 are given the same reference numerals. The communication relay system 100 includes duplicated communication relay devices. In the communication relay system 100, all communication networks except for the wireless network 301 (an example of a first wireless network) and the wireless network 302 (an example of a second wireless network) are wired.

[0023] The communication relay system 100 includes a gateway 101, a gateway 102, and a communication relay device 121 and a communication relay device 122 (both of which are examples of a first communication relay device) between the wireless terminal 111 and the wireless terminal 112. An in-vehicle network 20 (an example of a first network) to the wireless terminals 111 and 112 are configured on the vehicle side. For this reason, the communication relay device 121 and the communication relay device 122 are installed in the vehicle. The vehicle network according to this embodiment includes the communication relay device 121 and the communication relay device 122 in addition to the conventional in-vehicle network 20. Either an active system or a standby system that relays data between the in-vehicle network 20 and the wireless network 301 and the wireless network 302 is set in the communication relay devices 121 and 122.

[0024] The communication relay device 121 is connected to the gateways 101 and 102 and the wireless terminals 111 and 112. Specifically, the communication relay device 121 is connected to the gateway 101 by a communication line 201, and is connected to the gateway 102 by a communication line 203. The communication relay device 121 is also connected to the wireless terminal 111 by a communication line 211, and is connected to the wireless terminal 112 by a communication line 212. As described above, the communication lines 211 and 212 are wired lines.

[0025] The communication relay device 122 is connected to the gateways 101 and 102 and the wireless terminals 111 and 112. Specifically, the communication relay device 122 is connected to the gateway 101 by a communication line 202, and is connected to the gateway 102 by a communication line 204. In addition, the communication relay device 122 is connected to the wireless terminal 111 by a communication line 213, and is connected to the wireless terminal 112 by a communication line 214.

[0026] The communication relay device 121 and the communication relay device 122 are connected by a duplexed communication line 215 (an example of a first communication line) so that they can communicate signals with each other. The communication relay devices 121 and 122 monitor the status of their own system and the other system through the communication line 215 connected to each other, and share each other's settings and status. By duplicating the communication line 215, even if one communication line 215 malfunctions, communication can be continued through the other communication line 215. The communication line 215 is used, for example, by the communication relay device 121 and the communication relay device 122 to transmit heartbeat signals and status signals to each other. For this reason, it is desirable that the communication line 215 be a wired line.

[0027] The communication relay device 121 and the communication relay device 122 share information indicating whether the active system or the standby system is set. Also, the communication relay device 121 and the communication relay device 122 share information indicating that a fault has occurred in the communication line 215 or in either the communication relay device 121 or 122.

[0028] When the communication relay device 122 detects that a failure has occurred in the communication relay device 121, it transitions from a standby system to an active system. Then, the communication relay device 122 takes over the process of duplicating and transmitting data to the wireless networks 301 and 302. When the communication relay device 121 detects that a failure has occurred, it transitions from the active system to the standby system, and remains in the standby system even after the failure is recovered from.

[0029] The wireless terminal 111 is connected to the wireless terminal 113 via the wireless network 301. The wireless terminal 112 is connected to the wireless terminal 114 via the wireless network 302.

[0030] The communication relay system 100 includes a communication relay device 123 and a communication relay device 124 (both of which are examples of a second communication relay device) between the gateway 103 and the gateway 104 and the wireless terminal 113 and the wireless terminal 114. A base station network 30 (an example of a second network) to the wireless terminals 113 and 114 are configured on the ground side. For this reason, the communication relay device 123 and the communication relay device 124 are installed in a control station on the ground side.

[0031] The ground network according to this embodiment includes a communication relay device 123 and a communication relay device 124 in addition to a conventional base station network 30. Either an active system or a standby system that relays data between the base station network 30 and the wireless networks 301 and 302 to the base station network 30 is set in the communication relay devices 123 and 124.

[0032] The communication relay device 123 is connected to the gateways 103 and 104 and the wireless terminals 113 and 114. Specifically, the communication relay device 123 is connected to the gateway 103 via a communication line 231, and is connected to the gateway 104 via a communication line 232. In addition, the communication relay device 123 is connected to the wireless terminal 113 via a communication line 221, and is connected to the wireless terminal 114 via a communication line 223. As described above, the communication lines 221 and 223 are wired lines.

[0033] The communication relay device 124 is connected to the gateways 103 and 104 and the wireless terminals 113 and 114. Specifically, the communication relay device 124 is connected to the gateway 103 via a communication line 233, and is connected to the gateway 104 via a communication line 234. In addition, the communication relay device 124 is connected to the wireless terminal 113 via a communication line 222, and is connected to the wireless terminal 114 via a communication line 224. As described above, the communication lines 222 and 224 are wired lines.

[0034] The communication relay devices 123 and 124 are connected by a duplexed communication line 225 (an example of a second communication line) so that they can communicate signals with each other. The communication relay devices 123 and 124 monitor the status of their own system and the other system through the communication line 225 connected to each other, and share each other's settings and status. By duplexing the communication line 225, the communication relay devices 123 and 124 can continue communication through the other communication line 225 even if one communication line 225 malfunctions. The communication line 225 is used, for example, by the communication relay devices 123 and 124 to transmit heartbeat signals and status signals to each other. For this reason, it is preferable that the communication line 225 is a wired line.

[0035] The communication relay device 123 and the communication relay device 124 share information indicating whether the active system or the standby system is set. The communication relay device 123 and the communication relay device 124 also share information indicating that a failure has occurred in the communication line 225 or that a failure has occurred in either the communication relay device 123 or 124. When the communication relay device 124 detects that a failure has occurred in the communication relay device 123, it transitions from the standby system to the active system. Then, the communication relay device 124 takes over the process of duplicating and transmitting data to the wireless networks 301 and 302. When the communication relay device 123 detects that a failure has occurred, it transitions from the active system to the standby system, and remains as the standby system even after the failure is recovered from.

[0036] Each communication relay device (communication relay devices 121 to 124) can transition between an active state (active state) and a standby state (idle state). For example, when communication relay device 121 is the active state, communication relay device 122 is the standby state. In this way, when one communication relay device is the active state, the other communication relay device is the standby state.

[0037] The communication relay devices 121 and 122 periodically communicate with each other via a communication line 215, and the settings and status of the communication relay devices 121 and 122 are always shared. Similarly, the communication relay devices 123 and 124 periodically communicate with each other via a communication line 225, and the settings and system status of the communication relay devices 123 and 124 are always shared.

[0038] When communication on the communication line 215 or the communication line 225 is interrupted, the standby communication relay device determines that a failure has occurred in the active communication relay device, and promptly transitions to the active system. In this case, the active communication relay device does not transition to the standby system. For this reason, it is also acceptable for both communication relay devices to become the active system.

[0039] Moreover, transmission to the wireless networks 301 and 302 is performed only from the active communication relay device. The standby communication relay device does not transmit to the wireless networks 301 and 302 even if it receives a signal from the gateway. When the standby communication relay device receives a signal from the wireless network 301 and the wireless network 302, the standby communication relay device may transmit the signal to a gateway connected to the communication relay device.

[0040] <Internal configuration example of communication relay device> Here, an example of the internal configuration of the communication relay device will be described. 3 is a block diagram showing an example of the internal configuration of the communication relay device 121. Since the communication relay devices 122 to 124 have the same internal configuration as the communication relay device 121, a description of the internal configuration of the communication relay devices 122 to 124 will be omitted.

[0041] The communication relay device 121 relays data transmitted and received between the in-vehicle network 20 and the base station network 30 via the wireless networks 301 and 302. The communication relay device 121 includes a relay communication unit 11, a data processing unit 12, a buffer unit 13, a state storage unit 14, an other system monitoring unit 15, and an other system communication unit 16.

[0042] When the active system is set, the relay communication unit 11 relays data to the wireless networks 301 and 302, and when the standby system is set, the relay communication unit 11 does not relay data received from the in-vehicle network 20 to the wireless networks 301 and 302. For example, the relay communication unit 11 passes data received from the communication lines 201 and 203 on the in-vehicle network 20 side to the data processing unit 12. Then, the relay communication unit 11 transmits the data, to which a destination has been assigned by the data processing unit 12, to the wireless terminal 111 via the communication line 211. Similarly, the relay communication unit 11 transmits the data, to which a destination has been assigned by the data processing unit 12, to the wireless terminal 112 via the communication line 212.

[0043] Conversely, the relay communication unit 11 passes the data received from the communication lines 211 and 212 to the data processing unit 12. Then, the relay communication unit 11 transmits the data, to which a destination has been assigned by the data processing unit 12, to the gateway 101 via the communication line 201. Similarly, the relay communication unit 11 transmits the data, to which a destination has been assigned by the data processing unit 12, to the gateway 102 via the communication line 203.

[0044] The data processing unit 12 adds destination data to the data received by the relay communication unit 11. Note that the data processing unit 12 may delete communication path information from the data transferred from the wireless networks 301 and 302.

[0045] When the communication relay device 121 is in the standby system, the buffer unit 13 stores for a certain period of time the data received by the relay communication unit 11 and processed by the data processing unit 12. In the standby system, the communication relay device 121 does not transmit data to the wireless networks 301 and 302, but transitions to the active system when the communication line 215 is cut off.

[0046] After the communication relay device 121 transitions to the active system, it transmits data acquired from the buffer unit 13 to the wireless networks 301 and 302, and then continues to transmit data received from the gateways 101 and 102 to the wireless networks 301 and 302. With this operation, the communication relay device 121 can transmit data to the wireless networks 301 and 302 without losing any data.

[0047] The state storage unit 14 stores the state in which the communication relay device 121 itself is set as either the active system or the standby system. If the active system is stored in the state storage unit 14, the communication relay device 121 operates as the active system. On the other hand, if the standby system is stored in the state storage unit 14, the communication relay device 121 operates as the standby system. The data processing unit 12 refers to the state storage unit 14, and if the communication relay device 121 is the active system, it passes the processed data to the relay communication unit 11 to cause the wireless terminals 111 and 112 to transmit the data. On the other hand, the data processing unit 12 refers to the state storage unit 14, and if the communication relay device 121 is the standby system, it causes the buffer unit 13 to store the processed data.

[0048] The other system monitoring unit 15 writes the settings and state of the communication relay device 122 acquired by the other system communication unit 16 into the state storage unit 14, and monitors the communication relay device 122. For example, the other system monitoring unit 15 monitors for communication interruption on the communication line 215. If the other system monitoring unit 15 determines that communication on the communication line 215 has not been interrupted, it does not rewrite the state storage unit 14. However, if the other system monitoring unit 15 determines that communication on the communication line 215 has been interrupted and the standby system is stored in the state storage unit 14, it rewrites the state storage unit 14 to the active system.

[0049] The other system communication unit 16 is connected to a communication relay device 122 (an example of another communication relay device) via a communication line 215, and communicates with the communication relay device 122 via the communication line 215. For example, the other system communication unit 16 transmits a heartbeat signal to the communication relay device 122, which is the other system, and receives a heartbeat signal from the communication relay device 122. The other system communication unit 16 also transmits a signal of the state of its own system (active system or standby system) to the communication relay device 122. Then, the other system communication unit 16 transmits a signal of the state (standby system or active system) from the communication relay device 122 to the in-vehicle network 20.

[0050] <Example of computer hardware configuration> Next, the hardware configuration of the computer 60 constituting the communication relay device 121 will be described. 4 is a block diagram showing an example of a hardware configuration of the computer 60. The computer 60 is an example of hardware used as a computer capable of operating as the communication relay device 121 according to the present embodiment. Since the communication relay devices 122 to 124 have the same hardware configuration as the communication relay device 121, a description of the hardware configuration of the communication relay devices 122 to 124 will be omitted. In the communication relay system 100 and the communication relay device 121 according to this embodiment, each functional block is configured by a calculator 60 (computer) executing a program, and each functional block cooperates to realize a communication relay method described later in Figures 6, 8 and 9.

[0051] The computer 60 includes a central processing unit (CPU) 61, a read only memory (ROM) 62, and a random access memory (RAM) 63, each of which is connected to a bus 64. The computer 60 further includes a non-volatile storage 65 and a network interface 66.

[0052] The CPU 61 reads out program code of software for implementing each function according to the present embodiment from the ROM 62, loads it into the RAM 63, and executes it. Variables, parameters, etc. generated during the arithmetic processing of the CPU 61 are temporarily written into the RAM 63, and these variables, parameters, etc. are read out by the CPU 61 as appropriate.

[0053] As the nonvolatile storage 65, for example, a hard disk drive (HDD), a solid state drive (SSD), or a nonvolatile memory is used. In addition to an operating system (OS) and various parameters, a program for making the computer 60 function is recorded in this nonvolatile storage 65. In the ROM 62 and the nonvolatile storage 65, programs and data necessary for the CPU 61 to operate are recorded. That is, the ROM 62 and the nonvolatile storage 65 are used as an example of a computer-readable non-transient storage medium that stores a program executed by the computer 60.

[0054] For example, a network interface card (NIC) is used as the network interface 66. The network interface 66 transmits and receives various data between devices via a local area network (LAN) or a dedicated line connected to a terminal of the NIC.

[0055] <Data flow during normal operation> Fig. 5 is a block diagram showing an example of data flow during normal operation. Communication relay device 121 and communication relay device 123 are active systems, and communication relay device 122 and communication relay device 124 are standby systems. Fig. 5 shows only lines through which data is communicated, and does not show lines through which data is not transmitted.

[0056] Here, a case of uplink in which data is transmitted from the in-vehicle network 20 to the base station network 30 will be described. The gateway 101 transmits data to the communication relay device 121 via the communication line 201, and transmits the same data to the communication relay device 122 via the communication line 202. The gateway 102 transmits data to the communication relay device 121 via the communication line 203, and transmits the same data to the communication relay device 122 via the communication line 204.

[0057] For example, since the in-vehicle network 20 of a railway or the like is made redundant, the communication relay devices 121 and 122 receive the same data in duplicate. The data received by the communication relay devices 121 and 122 is not discarded, and the communication relay device 121 of the active system transmits the data to the in-vehicle network 20 via the wireless networks 301 and 302.

[0058] The communication relay device 121, which is an execution system, relays data received from the in-vehicle network 20 to the wireless networks 301 and 302. In addition, the communication relay device 121 relays data received from the base station network 30 via the wireless networks 301 and 302 to the in-vehicle network 20.

[0059] For example, the communication relay device 121 transmits data to the wireless terminal 111 via the communication line 211 , and also transmits the same data to the wireless terminal 112 via the communication line 212 . The communication relay device 122, which is a standby system, does not relay data received from the in-vehicle network 20 to the wireless networks 301 and 302. In addition, the communication relay device 122 does not relay data received from the base station network 30 via the wireless networks 301 and 302 to the in-vehicle network 20. For this reason, the communication relay device 122 does not transmit data to the wireless terminals 111 and 112.

[0060] The wireless terminal 111 transmits data to the wireless terminal 113 via the wireless network 301. The wireless terminal 112 transmits data to the wireless terminal 114 via the wireless network 302. The wireless terminal 113 transmits data to the communication relay device 123 via the communication line 221, and also transmits the same data to the communication relay device 124 via the communication line 222. The wireless terminal 114 transmits data to the communication relay device 123 via the communication line 223, and also transmits the same data to the communication relay device 124 via the communication line 224.

[0061] The communication relay device 123, which is the execution system, relays data received from the wireless networks 301 and 302 to the base station network 30. In addition, the communication relay device 123 relays data received from the base station network 30 to the wireless networks 301 and 302. For example, the communication relay device 123 transmits data to the gateway 103 via the communication line 231, and transmits the same data to the gateway 104 via the communication line 232.

[0062] The communication relay device 124 of the standby system does not relay data received from the wireless networks 301 and 302 to the base station network 30. Moreover, the communication relay device 124 does not relay data received from the base station network 30 to the wireless networks 301 and 302. For example, the communication relay device 124 does not transmit data to the gateways 103 and 104. The communication relay device 124 of the standby system may buffer data for a predetermined period of time. By buffering the data, the communication relay device 124 transitions to the active system and transmits data to the base station network 30 when an abnormality occurs in the communication relay device 123 of the active system.

[0063] <Sequence diagram for normal operation> Fig. 6 is a sequence diagram showing an example of normal operation of each device in the communication relay system 100. In Fig. 6, the communication relay devices 121 and 123 are active systems, and the communication relay devices 122 and 124 are standby systems. The communication relay devices 121 and 122 communicate with each other (S1) and monitor each other's status. Similarly, the communication relay devices 123 and 124 communicate with each other (S2) and monitor each other's status.

[0064] First, the flow of data transmitted from the gateway 101 and an example of the operation of each device will be described. The gateway 101 transmits data to the communication relay device 121 (S11), and transmits the same data to the communication relay device 122 (S12). The communication relay device 122 does not transmit data to the wireless terminals 111 and 112 because it is in a standby state.

[0065] On the other hand, since the communication relay device 121 is an execution system, it duplicates data and transmits it to the wireless networks 301 and 302. For example, the communication relay device 121 transmits data received from the gateway 101 to the wireless terminal 111 (S13), and also transmits the same data to the wireless terminal 112 (S14).

[0066] Wireless terminal 112 transmits data to wireless terminal 114 via wireless network 302 (S15). Wireless terminal 114 transmits the data received via wireless network 302 to communication relay device 124 (S16), and also to communication relay device 123 (S17). Communication relay device 124 is in a standby state and therefore has stopped transmitting data.

[0067] Since the communication relay device 123 is the execution system, when it receives duplicated data from the wireless networks 301 and 302, it relays the first-arrived data to the base station network 30. However, the communication relay device 123 does not relay the later-arrived data to the base station network 30. For example, the communication relay device 123 transmits data received from the wireless terminal 114 to the gateway 103 (S18), and transmits the same data to the gateway 104 (S19).

[0068] Having received data from communication relay device 121 in step 13, wireless terminal 111 transmits the data to wireless terminal 113 via wireless network 301 (S20). Wireless terminal 113 transmits the received data to communication relay device 124 (S21), and also transmits the same data to communication relay device 123 (S22). Communication relay device 124 is in the standby system and has stopped transmitting data. Communication relay device 123 is in the active system, but has already transmitted data in steps S18 and S19. For this reason, communication relay device 123 stops transmitting the same data due to its first-come-first-served function.

[0069] Next, a description will be given of the flow of data sent from the gateway 102 and an example of the operation of each device. The gateway 102 transmits data to the communication relay device 121 (S31), and transmits the same data to the communication relay device 122 (S32). The communication relay device 122 is a standby device, and does not transmit data to the wireless terminals 111 and 112. On the other hand, since the communication relay device 121 is the active system, it transmits the data received from the gateway 102 to the wireless terminal 111 (S33), and also transmits the same data to the wireless terminal 112 (S34).

[0070] The data flow and operation example of each device in the following steps S35 to S42 are the same as the data flow and operation example of each device in steps S15 to S22, so a duplicated description will be omitted.

[0071] Although data may not be transmitted to the gateway 104, there are specifications that suffice as long as data is transmitted to the gateway 103. Therefore, depending on the specifications of the communication relay devices 123 and 124, the processes of steps S19, S21, and S22 in FIG.

[0072] <Data flow when a failure occurs> Next, the flow of data when a failure occurs in the communication relay device 121, which is the active system, will be described. FIG. 7 is a sequence diagram showing an example of the operation of each device in the communication relay system when a failure occurs in the communication relay device 121. In FIG.

[0073] When a failure occurs in the communication relay device 121, it is not possible to know whether the communication relay device 121 is correctly transmitting data to the wireless terminals 111 and 112. For this reason, the communication lines 211 and 212 are represented by dashed lines in FIG.

[0074] When the communication relay device 122, which acquires the status of the communication relay device 121 from the communication line 215, detects the occurrence of a fault in the communication relay device 121, the communication relay device 122 immediately transitions from the standby system to the active system regardless of whether the communication relay device 121 is in the active system or standby system state. After that, the communication relay device 122 transmits data to the wireless terminal 111 via the communication line 213, and transmits the same data to the wireless terminal 112 via the communication line 214. Therefore, the communication relay device 122 can maintain the continuity of data transmitted from the vehicle network to the ground network.

[0075] The wireless terminal 111 transmits data to the wireless terminal 113 via the wireless network 301. The wireless terminal 112 transmits data to the wireless terminal 114 via the wireless network 302. The subsequent data flow is as described in FIG.

[0076] When the failure of communication relay device 121 is recovered, either communication relay device 121 or communication relay device 122 becomes the active system depending on the initial setting value and the severity of the failure. The communication relay device that has transitioned to the standby system does not transmit data to wireless networks 301 and 302. Therefore, the wireless relay device that has transitioned to the standby system stops transmitting data to wireless terminals. For example, it is better for a communication relay device that fails frequently to remain in the standby system even after recovering from a failure. Therefore, the initial setting is set so that a communication relay device that fails frequently remains in the standby system even after recovery from a failure.

[0077] Also, if the level of the failure is at the level of a warning, there is no problem if the communication relay device 121 is returned to the active system after recovering from the failure. However, if the level of the failure is an error worse than a warning or an equipment failure, the communication relay device 121 will not operate normally even if it is returned to the active system after recovering from the failure. For this reason, the transition of the communication relay device 121 between the active system and the standby system when recovering from the failure changes depending on the level of the failure.

[0078] <Sequence diagram when a failure occurs> FIG. 8 is a sequence diagram showing an example of the operation of each device in the communication relay system 100 when a failure occurs in the communication relay device 121, which is the active system. When a failure occurs in the communication relay device 121, the communication between the communication relay devices 121 and 122 is interrupted (S51). As a result, the communication relay device 122 transitions from a standby system to an active system. On the other hand, the communication relay devices 123 and 124 can communicate with each other (S52) and monitor each other's status.

[0079] First, the flow of data transmitted from the gateway 101 and an example of the operation of each device will be described. The gateway 101 transmits data to the communication relay device 121 (S61), and transmits the same data to the communication relay device 122 (S62). Since a failure has occurred in the communication relay device 121, unlike the data flow in Fig. 6, data transmission processing originating from the communication relay device 121 is not performed or communication is undefined.

[0080] Since the communication relay device 122 has transitioned to the active system, it transmits the data received from the gateway 101 to the wireless terminal 111 (S63), and also transmits the same data to the wireless terminal 112 (S64).

[0081] The data flow and the operation example of each device in the subsequent steps S65 to S72 are the same as the data flow and the operation example of each device in steps S15 to S22 in FIG. 6, so a duplicated description will be omitted.

[0082] Next, a description will be given of the flow of data sent from the gateway 102 and an example of the operation of each device. The gateway 102 transmits data to the communication relay device 121 (S81), and transmits the same data to the communication relay device 122 (S82). Since a failure has occurred in the communication relay device 121, unlike the data flow in Fig. 6, data transmission processing originating from the communication relay device 121 is not performed or communication is undefined.

[0083] Since the communication relay device 122 has transitioned to the active system, it transmits the data received from the gateway 101 to the wireless terminal 111 (S83), and also transmits the same data to the wireless terminal 112 (S84).

[0084] The data flow and operation example of each device in the following steps S85 to S92 are the same as the data flow and operation example of each device in steps S15 to S22, so a duplicated description will be omitted.

[0085] <Failure recovery sequence diagram> FIG. 9 is a sequence diagram showing an example of the operation of each device of the communication relay system 100 when the communication relay device 121 recovers from a failure. As described above, the communication relay device 121 in which a failure has occurred does not transition to the active system even after the failure is recovered, but remains in the standby system. However, since the communication relay device 121 has recovered from the failure, it is able to communicate with the communication relay device 122 (S101) and monitors each other's status. In addition, the communication relay devices 123 and 124 are also able to communicate with each other (S102) and monitor each other's status.

[0086] First, the flow of data transmitted from the gateway 101 and an example of the operation of each device will be described. The gateway 101 transmits data to the communication relay device 121 (S111), and transmits the same data to the communication relay device 122 (S112). The communication relay device 122 is a standby device, and does not transmit data to the wireless terminals 111 and 112.

[0087] On the other hand, since the communication relay device 122 is the active system, it transmits the data received from the gateway 101 to the wireless terminal 111 (S113), and also transmits the same data to the wireless terminal 112 (S114). The data flow and the operation example of each device in the subsequent steps S115 to S122 are the same as the data flow and the operation example of each device in steps S15 to S22 in FIG. 6, so a duplicated description will be omitted.

[0088] Next, a description will be given of the flow of data sent from the gateway 102 and an example of the operation of each device. The gateway 102 transmits data to the communication relay device 121 (S131), and transmits the same data to the communication relay device 122 (S132). The communication relay device 122 is a standby device, and does not transmit data to the wireless terminals 111 and 112.

[0089] On the other hand, since the communication relay device 122 is the active system, it transmits the data received from the gateway 101 to the wireless terminal 111 (S133), and also transmits the same data to the wireless terminal 112 (S134).

[0090] The data flow and the operation example of each device in the subsequent steps S135 to S142 are the same as the data flow and the operation example of each device in steps S15 to S22 in FIG. 6, so a duplicated description will be omitted.

[0091] So far, the flow of signals transmitted from the vehicle network to the ground network (in the case of uplink) has been described. Note that the flow of signals transmitted from the ground network to the vehicle network (in the case of downlink) also operates in the opposite manner to the signal flow in the case of uplink, with the communication relay devices 121 to 124. Here, detailed descriptions of the signal flow in the case of downlink and the operation of each device using sequence diagrams will be omitted.

[0092] In the communication relay system 100 according to the embodiment described above, one of the two communication relay devices in the data transmitting in-vehicle network 20 is an active system and the other is a standby system. The active system communication relay device transmits data to the wireless network, but the standby system communication relay device does not transmit data to the wireless network. Therefore, since there is no data transmitted from the standby system communication relay device to the wireless network, the communication bandwidth of the data transmitted to the wireless network can be reduced. Since the public network lines of mobile communication carriers are often on a pay-per-use basis, the communication relay system 100 according to the present embodiment has the effect of reducing communication costs.

[0093] In addition, in the communication relay system 100 according to this embodiment, the two communication relay devices monitor each other's operation, and if a failure occurs in the active communication relay device and communication is interrupted, the standby communication relay device immediately switches to the active system. After that, the communication relay device that has switched to the active system transmits data to the wireless network, shortening communication dead time and preventing data loss. Also, data is reliably delivered to the gateway at the end of the wireless network.

[0094] Furthermore, since the communication relay device that has recovered from the failure continues to operate as a standby system, it does not transmit unnecessary data to the wireless network, and therefore the communication band of the wireless network is not overwhelmed by data. In addition, two communication relay devices are installed on the data receiving side, and the two communication relay devices monitor each other's operation. Data received by the wireless terminal on the data receiving side from the wireless network is sent to the communication relay device on the data receiving side, and the data is transferred from this communication relay device to the gateway on the data receiving side.

[0095] Here, the communication relay device on the data receiving side gives priority to transmitting data received first from a wireless terminal to the gateway, and does not transmit data received thereafter from another wireless terminal to the gateway. Therefore, the gateway on the data receiving side does not receive the same data twice, and does not need to perform processes such as duplicate determination and data discarding regarding data reception.

[0096] The present invention is not limited to the above-described embodiment, and various other applications and modifications are possible without departing from the gist of the present invention as set forth in the claims. For example, the above-mentioned embodiment describes the system configuration in detail and specifically in order to explain the present invention in an easily understandable manner, and is not necessarily limited to a system having all of the described configurations. In addition, it is also possible to add, delete, or replace part of the configuration of the present embodiment with other configurations. In addition, the control lines and information lines shown are those that are considered necessary for the explanation, and not all control lines and information lines in the product are necessarily shown. In reality, it can be considered that almost all components are connected to each other. [Explanation of symbols]

[0097] 11... relay communication unit, 12... data processing unit, 13... buffer unit, 14... status storage unit, 15... other system monitoring unit, 16... other system communication unit, 20... vehicle-mounted network, 30... base station network, 100... communication relay system, 101-104... gateways, 111-114... wireless terminals, 121-124... communication relay devices, 201-204, 211-215, 221-225, 231-234... communication lines, 301, 302... wireless network

Claims

1. A communication relay system that relays data transmitted and received between a first network and a second network via a first wireless network and a second wireless network, two first communication relay devices each configured as an active system or a standby system, which relay the data between the first network and the first wireless network and between the first network and the second wireless network; the second network, and two second communication relay devices each set as an active system or a standby system for relaying the data between the second network and the first wireless network and the second wireless network; the first communication relay device of an active system relays the data received from the first network to the first wireless network and the second wireless network; the first communication relay device of a standby system does not relay the data received from the first network to the first wireless network and the second wireless network, the second communication relay device of an active system relays the data received from the first wireless network and the second wireless network to the second network; The second communication relay device of a standby system does not relay the data received from the first wireless network and the second wireless network to the second network. Communications relay system.

2. the first communication relay device of an active system duplicates the data and transmits the duplicated data to the first wireless network and the second wireless network; The second communication relay device of the active system receives the duplicated data from the first wireless network and the second wireless network, relays the first-arrived data to the second network, and does not relay the later-arrived data to the second network. The communication relay system according to claim 1 .

3. The two first communication relay devices monitor the states of their own system and the other system through a first communication line connected to each other, and share settings and states with each other; The two second communication relay devices monitor the states of their own system and the other system through a second communication line connected to each other, and share the settings and states of each other. The communication relay system according to claim 2 .

4. When the first communication relay device of the standby system detects that a failure has occurred in the first communication relay device of the active system, the first communication relay device of the standby system transitions from the standby system to the active system and takes over the process of transmitting the data in a duplicated manner to the first wireless network and the second wireless network. The communication relay system according to claim 3 .

5. The first communication relay device, in which the occurrence of a failure is detected, transitions from an active system to a standby system, and remains in the standby system even after the failure is recovered. The communication relay system according to claim 4.

6. When the occurrence of a failure is detected, the first communication relay device transitions from an active system to a standby system, and after the failure is recovered, one of the first communication relay devices becomes the active system depending on the initial setting and the degree of the failure, and the first communication relay device that has transitioned to the standby system does not transmit the data to the first wireless network and the second wireless network. The communication relay system according to claim 4.

7. The setting is information indicating whether an active system or a standby system is set, and the state is information indicating that a fault has occurred in the first communication line or the second communication line, or that a fault has occurred in the first communication relay device or the second communication relay device. The communication relay system according to claim 4.

8. the first communication relay device of the active system relays data received from the second network via the first wireless network and the second wireless network to the first network; the first communication relay device of a standby system does not relay data received from the second network via the first wireless network and the second wireless network to the first network, the second communication relay device of an active system relays the data received from the second network to the first wireless network and the second wireless network; The second communication relay device of a standby system does not relay the data received from the second network to the first wireless network and the second wireless network. The communication relay system according to claim 4.

9. A communication relay device that relays data transmitted and received between a first network and a second network via a first wireless network and a second wireless network, a state storage unit that stores a state in which either the active system or the standby system is set; a relay communication unit that relays the data to the first wireless network and the second wireless network when an active system is set, and does not relay the data received from the first network to the first wireless network and the second wireless network when a standby system is set. Communications relay device.

10. an other-system communication unit that is connected to another communication relay device via a communication line and communicates with the other communication relay device via the communication line; an other-system monitoring unit that writes the settings and states of the other communication relay devices acquired by the other-system communication unit into the state storage unit and monitors the other communication relay devices; The communication relay device according to claim 9.

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