JP2020129842A - On-vehicle communication system, switch device, and on-vehicle communication method - Google Patents

Abstract

To appropriately perform redundant switching in an on-vehicle network.SOLUTION: An on-vehicle communication system mounted on a vehicle comprises a first switch device, second switch device, and third switch device, each of which includes a first communication port and second communication port. The first switch device's first communication port and second communication port are connected to the second switch device's first communication port and the third switch device's first communication port, respectively. The second switch's second communication port is connected to the third switch device's second communication port. Each switch device measures reception signal quality of the switch device's first communication port and second communication port; and, on the basis of reception signal quality of a use port selected as a communication port to be used of the device's first communication port and second communication port, performs switching processing for determining whether or not to switch the use port to another communication port.SELECTED DRAWING: Figure 3

Description

The present invention relates to an in-vehicle communication system, a switch device, and an in-vehicle communication method.

2. Description of the Related Art Conventionally, a technique has been developed for making a system redundant (redundant) in order to provide a high quality service.

For example, Patent Document 1 (JP-A-2016-12932) discloses the following station side device. That is, the station-side device includes operating (active) OSUs 1 to N, a standby (standby) OSU N+1, and a control unit. The control unit transfers the management information of the ONU associated with the logical line with the network management system (NMS). A logical line is defined by a fixed combination of an optical line unit and a passive optical network. On the other hand, the OSU acquires the management information associated with the real line. The real line represents the actual combination of optical line unit and passive optical network. The control unit uses the mapping information to convert the line associated with the management information between the logical line and the real line.

JP, 2016-12932, A JP, 2005-88815, A

For example, a configuration in which the redundant configuration described in Patent Document 1 is applied to an in-vehicle network can be considered. However, in a vehicle, noise sources such as an engine and a motor may be placed close to the signal line because of space limitations.

With such an arrangement, the communication environment deteriorates rapidly in accordance with the operation of the noise source, so that the noise level of the signal transmitted through the signal line, for example, rises sharply and the communication quality deteriorates. In this case, communication may be difficult, which is not preferable. There is a demand for a technology capable of appropriately performing redundant switching in an in-vehicle network according to the communication environment.

The present invention has been made to solve the above problems, and an object thereof is to provide an in-vehicle communication system, a switch device, and an in-vehicle communication method capable of appropriately performing redundant switching in an in-vehicle network. ..

(1) In order to solve the above problems, an in-vehicle communication system according to an aspect of the present invention is an in-vehicle communication system mounted in a vehicle, each of which includes a first communication port and a second communication port. A first switch device, a second switch device, and a third switch device, wherein the first switch device has a first communication port and a second communication port that are the first switch device of the second switch device. And a second communication port of the third switch device, and a second communication port of the second switch device and a second communication port of the third switch device, respectively. Each of the first switching device, the second switching device, and the third switching device measures the reception signal quality of its own first communication port and the reception signal quality of its own second communication port. , The first switch device, the second switch device, and the third switch device are selected as communication ports to be used from among their own first communication port and second communication port. Based on the received signal quality of the used port, a switching process is performed to determine whether to switch the used port to another communication port.

(6) In order to solve the above problems, a switch device according to an aspect of the present invention is a switch device mounted on a vehicle, and measures a plurality of communication ports and the reception signal quality of each of the communication ports. Based on the received signal quality of the measuring unit and the used port selected as the communication port to be used measured by the measuring unit, it is determined whether or not the used port is switched to another communication port. And a switching processing unit that performs switching processing.

(7) In order to solve the above problems, an in-vehicle communication method according to an aspect of the present invention is an in-vehicle communication method in an in-vehicle communication system mounted on a vehicle, wherein each of the in-vehicle communication systems has a first A first switch device, a second switch device, and a third switch device each having a communication port and a second communication port, and the first communication port and the second communication port of the first switch device are , A second communication port of the second switch device and a third communication device of the second switch device, which are respectively connected to the first communication port of the second switch device and the first communication port of the third switch device. Second communication port is connected to each of the first switch device, the second switch device, and the third switch device, and the received signal quality of its own first communication port and its own second Measuring the received signal quality of the communication port of each of the first switching device, the second switching device, and the third switching device, the first switching device, the second switching device, and the third switching device each having their own first communication port and second communication port. Among them, a step of performing a switching process for determining whether to switch the used port to another communication port based on the received signal quality of the used port selected as the communication port to be used.

The present invention can be realized not only as an in-vehicle communication system including such a characteristic processing unit but also as a semiconductor integrated circuit that realizes a part or all of the in-vehicle communication system.

The present invention can be realized not only as a switch device including such a characteristic processing unit, but also as a method having such characteristic processing as steps, and the steps of such characteristic processing in a computer. It can be realized as a program for execution. Further, the present invention can be realized as a semiconductor integrated circuit that realizes a part or all of the switch device.

According to the present invention, redundancy switching in an in-vehicle network can be appropriately performed.

FIG. 1 is a diagram showing the configuration of an in-vehicle communication system according to the first embodiment of the present invention. FIG. 2 is a diagram showing a configuration of the switch device in the vehicle-mounted communication system according to the first embodiment of the present invention. FIG. 3 is a diagram showing the details of the connection between the switch devices in the vehicle-mounted communication system according to the first embodiment of the present invention. FIG. 4 is a diagram showing an example of an SNR table held by the storage unit in the switch device according to the first embodiment of the present invention. FIG. 5 is a flowchart defining an operation procedure when the switch device in the monitoring system according to the first embodiment of the present invention performs a switching process. FIG. 6 is a diagram showing a configuration of an in-vehicle communication system according to the second embodiment of the present invention. FIG. 7: is a figure which shows the structure of the switch apparatus in the vehicle-mounted communication system which concerns on the 2nd Embodiment of this invention.

First, the contents of the embodiments of the present invention will be listed and described.

(1) An in-vehicle communication system according to an embodiment of the present invention is an in-vehicle communication system mounted on a vehicle, each of which has a first communication port and a second communication port, A second switch device and a third switch device, wherein the first communication port and the second communication port of the first switch device are the first communication port and the third communication port of the second switch device, respectively. The second communication port of the second switch device and the second communication port of the third switch device are respectively connected to the first communication port of the switch device of Each of the second switch device and the third switch device measures the received signal quality of its own first communication port and the received signal quality of its own second communication port, and the first switch device , The second switch device and the third switch device each have a received signal quality of a used port selected as a communication port to be used from the first communication port and the second communication port of the second switch device. On the basis of the above, a switching process for determining whether to switch the used port to another communication port is performed.

In this way, in each switch device, when the received signal quality of the first communication port and the second communication port is measured, for example, when the deterioration of the received signal quality due to the increase of the noise level is detected for the signal of the used port. Moreover, it is possible to appropriately determine that the used port should be switched to another communication port, and switch the used port to another communication port. As a result, it is possible to appropriately perform redundant switching in which the communication path passing through the used port is switched to the communication path passing through another communication port, and it is possible to prevent the situation where communication is difficult from continuing. .. Therefore, the redundant switching in the vehicle-mounted network can be appropriately performed.

(2) Preferably, each of the first switch device, the second switch device, and the third switch device has a plurality of temperatures of itself and a determination reference in the switching process regarding the received signal quality. The correspondence relationship is held, the temperature of itself is acquired, and the switching process is performed based on the acquired temperature and the correspondence relationship.

With such a configuration, for example, when the lower limit of the SNR (Signal-to-Noise Ratio) that can favorably perform the signal processing of the received signal changes according to the temperature, the determination according to the temperature of the switch device is performed. Criteria can be obtained from the above correspondence. Thereby, for example, when it is difficult to perform the signal processing well, it can be determined that the used port should be switched to another communication port.

(3) More preferably, each of the first switch device, the second switch device, and the third switch device holds the correspondence relationship for each communication port.

With such a configuration, for example, when the lower limit temperature change of the SNR capable of favorably performing the signal processing of the received signal is different for each communication port, a determination criterion depending on the temperature of the switch device and the communication port is provided. It can be obtained from the above correspondence.

(4) More preferably, each of the first switching device, the second switching device, and the third switching device acquires the reception signal quality of the communication port in another switching device and the correspondence relationship, The switching process is performed based on the acquired received signal quality and the obtained correspondence relationship.

With such a configuration, it is possible to determine whether or not the signal processing of the reception signal in the other switch device is favorably performed, and thus it is possible to determine the communication path to the target switch device via the other switch device. The superiority or inferiority of the communication path to the target switch device can be comprehensively determined without passing through the other switch device.

(5) More preferably, the communication ports of the first switch device, the second switch device, and the third switch device are connected by a cable for Ethernet (registered trademark) communication, and the first switch device is connected to the communication port of the first switch device. The switch device, the second switch device, and the third switch device are further connected by a cable for serial communication.

With such a configuration, the reception signal quality of the communication port in the other switch device and the above correspondence can be reliably obtained from the dedicated cable for serial communication, so that the switching process can be performed quickly.

(6) A switch device according to an embodiment of the present invention is a switch device mounted on a vehicle, comprising a plurality of communication ports, a measuring unit that measures received signal quality of each of the communication ports, and the measuring unit. Based on the received signal quality of the use port selected as the communication port to be used, which is measured by, a switching processing unit that performs a switching process for determining whether to switch the use port to another communication port. With.

In this way, the switch device measures the received signal quality of the signal of each communication port, and when, for example, the deterioration of the received signal quality of the signal of the used port due to the increase of the noise level is detected, the used port is changed to another port. It is possible to appropriately determine that the communication port should be switched to and switch the used port to another communication port. As a result, it is possible to appropriately perform redundant switching in which the communication path passing through the used port is switched to the communication path passing through another communication port, and it is possible to prevent the situation where communication is difficult from continuing. .. Therefore, the redundant switching in the vehicle-mounted network can be appropriately performed.

(7) An in-vehicle communication method according to an embodiment of the present invention is an in-vehicle communication method in an in-vehicle communication system mounted on a vehicle, wherein each of the in-vehicle communication systems includes a first communication port and a second communication port. A first switch device having a communication port, a second switch device, and a third switch device, wherein the first communication port and the second communication port of the first switch device are the second switch device. Connected to the first communication port of the third switch device and the second communication port of the second switch device and the second communication port of the third switch device, respectively. Each of the first switching device, the second switching device, and the third switching device that are connected to each other has a reception signal quality of its own first communication port and a reception signal quality of its own second communication port. And a communication to be used by each of the first switching device, the second switching device, and the third switching device among its own first communication port and second communication port. Performing a switching process for determining whether to switch the used port to another communication port based on the received signal quality of the used port selected as the port.

In this way, in each switch device, when the received signal quality of the first communication port and the second communication port is measured, for example, when the deterioration of the received signal quality due to the increase of the noise level is detected for the signal of the used port. Moreover, it is possible to appropriately determine that the used port should be switched to another communication port, and switch the used port to another communication port. As a result, it is possible to appropriately perform redundant switching in which the communication path passing through the used port is switched to the communication path passing through another communication port, and it is possible to prevent the situation where communication is difficult from continuing. .. Therefore, the redundant switching in the vehicle-mounted network can be appropriately performed.

Embodiments of the present invention will be described below with reference to the drawings. It should be noted that the same or corresponding parts in the drawings are designated by the same reference numerals and description thereof will not be repeated. Further, at least a part of the embodiments described below may be arbitrarily combined.

<First Embodiment>
[Configuration and basic operation]
FIG. 1 is a diagram showing the configuration of an in-vehicle communication system according to the first embodiment of the present invention.

Referring to FIG. 1, the in-vehicle communication system 301 includes switch devices 101A, 101B, 101C. Hereinafter, each of the switch devices 101A, 101B, and 101C is also referred to as a switch device 101.

The in-vehicle communication system 301 is installed in a vehicle. Further, for example, the plurality of in-vehicle communication devices 111, out-of-vehicle communication devices 112, central gateway 113 and control device 114 are mounted in the vehicle.

It should be noted that the vehicle is not limited to the configuration in which the plurality of in-vehicle communication devices 111 are mounted, and may be the configuration in which one in-vehicle communication device 111 is mounted. In addition, the vehicle is not limited to the configuration in which one out-of-vehicle communication device 112 is mounted, and may be a configuration in which a plurality of out-of-vehicle communication devices 112 are mounted.

The in-vehicle communication device 111 is, for example, a human-machine interface, a camera, a sensor, a navigation device, or the like, and can communicate with the switch device 101.

The out-of-vehicle communication device 112 can perform wireless communication with a wireless base station device (not shown) according to a communication standard such as LTE (Long Term Evolution) or 3G, and can communicate with the switch device 101A. Is.

The control device 114 is, for example, an engine control unit, an AT (Automatic Transmission) control unit, an HEV (Hybrid Electric Vehicle) control unit, a brake control unit, a chassis control unit, a steering control unit, or the like.

The central gateway 113 can communicate with the control device 114 via a CAN (Controller Area Network), and can communicate with the switch device 101A.

The central gateway 113 performs a relay process of information exchanged between the control device 114, the in-vehicle communication device 111, and the out-of-vehicle communication device 112.

Although the in-vehicle communication device 301 has the configuration in which the vehicle exterior communication device 112 and the central gateway 113 are directly connected to the switch device 101A, the invention is not limited to this. The vehicle exterior communication device 112 and the central gateway 113 may be directly connected to different switch devices 101.

The switch devices 101A to 101C are connected to each other by, for example, a vehicle-mounted Ethernet communication cable (hereinafter also referred to as an Ethernet cable) 10. The switch device 101 is connected to the in-vehicle communication device 111, the out-of-vehicle communication device 112, and the central gateway 113 by the Ethernet cable 10, for example.

The switch device 101 can communicate with the in-vehicle communication device 111, the vehicle exterior communication device 112, and the central gateway 113 that are directly connected to itself, and can communicate with another switch device 101.

Information is exchanged between the switch device 101 and other devices directly connected to the switch device 101 by using, for example, an Ethernet frame.

The environments of the switch devices 101A to 101C are different, for example. More specifically, the switch devices 101A to 101C are provided at different places such as the dashboard of the vehicle, the front part and the rear part of the vehicle, and have different ambient temperatures.

[Task]
The Ethernet cable 10 connecting between the switch devices 101 is affected by, for example, low frequency noise from the engine and clock noise from each device. These noises can be sudden or stationary.

The Ethernet cable 10 may receive noise depending on the arrangement of the noise source and itself. For this reason, noise may be superimposed on the signal transmitted between the switch devices 101, and steady or sudden deterioration in signal quality may occur.

Since it is difficult to detect the deterioration of signal quality due to the increase in noise as described above by the impedance measurement method usually used for detecting the disconnection of the signal line, the communication path is switched when the signal quality is deteriorated. It is difficult to realize redundancy.

Therefore, the vehicle-mounted communication system according to the embodiment of the present invention solves such a problem by the following configurations and operations.

[Configuration of switch device 101]
FIG. 2 is a diagram showing a configuration of the switch device in the vehicle-mounted communication system according to the first embodiment of the present invention.

Referring to FIG. 2, the switch device 101 includes a switch unit (measurement unit) 31, a control unit (switching processing unit) 32, a storage unit 33, a plurality of communication ports 34, and a temperature sensor 35.

The switch unit 31, the control unit 32, the storage unit 33, and the temperature sensor 35 are provided on the substrate 36. At least one of the switch unit 31, the control unit 32, the storage unit 33, and the temperature sensor 35 may be provided on a different substrate.

The temperature sensor 35 measures the temperature Ta of the substrate 36, and outputs temperature information indicating the measurement result to the control unit 32, for example, periodically.

The communication port 34 is, for example, a terminal to which the Ethernet cable 10 can be connected. The communication port 34 may be a terminal of the integrated circuit.

The Ethernet cable 10 is connected to each communication port 34. More specifically, the communication port 34A, which is the communication port 34, is connected to the communication port 34 in another switch device 101 via the Ethernet cable 10. The communication port 34B, which is the communication port 34, is connected to the communication port 34 in another switch device 101 different from the other switch device 101 via the Ethernet cable 10.

FIG. 3 is a diagram showing the details of the connection between the switch devices in the vehicle-mounted communication system according to the first embodiment of the present invention. In FIG. 3, in each of the switch devices 101A to 101C, communication ports 34A and 34B used for communication between the switch devices 101 are shown. Further, in FIG. 3, a part of the in-vehicle communication device 111, the out-of-vehicle communication device 112, the central gateway 113, and the control device 114 are not shown.

Referring to FIG. 3, the communication port 34A and the communication port 34B of the switch device 101A are respectively connected to the communication port 34A of the switch device 101B and the communication port 34A of the switch device 101C via the Ethernet cable 10.

The communication port 34B of the switch device 101B and the communication port 34B of the switch device 101C are connected via the Ethernet cable 10.

That is, the switch devices 101A to 101C form a ring network.

Referring back to FIG. 2, each of the plurality of communication ports 34 other than the communication ports 34A and 34B is one of the in-vehicle communication device 111, the out-of-vehicle communication device 112, and the central gateway 113 via the Ethernet cable 10. It is connected to the.

The switch unit 31 is specifically a layer 2 (L2) switch and has a signal processing circuit for each communication port 34. Each signal processing circuit is assigned a unique address, for example, a MAC (Media Access Control) address. Each signal processing circuit can communicate with the other switch device 101, the in-vehicle communication device 111, the out-of-vehicle communication device 112, and the central gateway 113 via the corresponding communication port 34.

The switch unit 31 in the switch device 101A can also perform, for example, layer 3 (L3) routing. The switch unit 31 in each of the switch devices 101B and 101C may have a configuration capable of performing L3 routing.

The switch unit 31 transmits an Ethernet frame received from a certain device to another device according to its destination.

More specifically, the switch unit 31 transmits the received Ethernet frame to another device based on the routing information received from the control unit 32 and the source address and the destination address included in the Ethernet frame.

Referring again to FIG. 3, the switch unit 31 in the switch device 101A directly connects to the switch device 101C as an address of the in-vehicle communication device 111A which is the in-vehicle communication device 111 directly connected to itself as a source address and as a destination address. When the Ethernet frame including the address of the in-vehicle communication device 111C, which is the in-vehicle communication device 111, is received, the following processing is performed.

That is, when the routing information includes that the Ethernet frame transmitted from the in-vehicle communication devices 111A to 111C should be directly transmitted to the switch device 101C, the switch unit 31 in the switch device 101A switches the Ethernet frame via the communication port 34B. It is transmitted to the device 101C.

On the other hand, the switch unit 31 in the switch device 101A communicates the Ethernet frame if the routing information includes that the Ethernet frame transmitted from the in-vehicle communication devices 111A to 111C should be transmitted to the switch device 101C via the switch device 101B. It transmits to the switch apparatus 101B via the port 34A.

Referring again to FIG. 2, the switch unit 31 measures the received signal quality of each communication port 34. More specifically, the switch unit 31 measures the SNR of the received signal including the Ethernet frame, which is an example of the received signal quality, for each communication port 34, and periodically outputs the SNR information indicating the measurement result to the control unit 32, for example. To do. In this example, the larger the SNR value, the smaller the noise and the better the received signal quality.

FIG. 4 is a diagram showing an example of an SNR table held by the storage unit in the switch device according to the first embodiment of the present invention.

Referring to FIG. 4, storage unit 33 is, for example, a non-volatile memory, and holds a correspondence relationship between a plurality of temperatures of itself and a determination criterion in the switching process for the received signal quality. This switching process will be described later.

More specifically, for example, the SNR table ST1 which is an example of the above correspondence is registered in the storage unit 33 for each communication port 34.

The SNR table ST1 includes, for example, the correspondence relationship between the temperature Ta of the substrate 36 and the threshold value Th1 at which the switching process should be performed at the temperature Ta.

The SNR table ST1 is created, for example, by the following method. That is, the developer calculates a CRC (Cyclic Redundancy Check) value based on the data included in the Ethernet frame received via the target communication port 34, for example. The developer compares the calculated CRC value with the value included in the FCS (Frame Check Sequence) field in the Ethernet frame (hereinafter, also referred to as the FCS value).

For example, the developer records the probability of occurrence of mismatch between the CRC value and the FCS value while changing the SNR at a certain temperature Ta. Then, the developer adopts the SNR at which the probability of occurrence of mismatch exceeds a predetermined value as the threshold Th1 of the target communication port 34 at the temperature Ta.

The developer completes the SNR table ST1 by similarly determining the threshold value Th1 at other temperatures Ta.

Further, in the storage unit 33, for example, route information indicating the connection topology of each device in the in-vehicle communication system 301 is registered.

The control unit 32 determines whether to switch the used port to another communication port 34 based on the received signal quality of the used port selected as the communication port 34 to be used, which is measured by the switch unit 31. Perform switching processing.

Here, the used port is, for example, the communication port 34 designated by the routing information. Specifically, in the switch device 101A shown in FIG. 3, when the routing information includes that the Ethernet frame transmitted from the in-vehicle communication devices 111A to 111C should be directly transmitted to the switch device 101C, the communication port 34B is the used port. Becomes

Further, when the routing information includes that the Ethernet frame transmitted from the in-vehicle communication devices 111A to 111C should be transmitted to the switch device 101C via the switch device 101B, the communication port 34A becomes the used port.

The used port may be operated fixedly or fluidly. When the used port is operated fluidly, the used port may be changed according to the source and the destination of the Ethernet frame, for example. Specifically, for the Ethernet frame transmitted from the in-vehicle communication devices 111A to 111C, the in-vehicle communication device 111 directly connected to the switch device 101C from the in-vehicle communication device 111A uses the communication port 34B as a used port. For an Ethernet frame transmitted to a certain in-vehicle communication device 111D, the communication port 34A may be used as a used port.

The control unit 32 acquires the temperature of its own switch device 101, for example. Specifically, the control unit 32 receives temperature information from the temperature sensor 35.

The control unit 32 performs the switching process based on, for example, the received signal quality of the used port, the acquired temperature, and the SNR table ST1. In other words, the control unit 32 performs the switching process using, for example, the determination standard corresponding to the received signal quality of the used port and the temperature Ta.

The control unit 32 recognizes the threshold value Th1 for each communication port 34 based on the measurement result of the temperature Ta indicated by the temperature information received from the temperature sensor 35 and the SNR table ST1.

Further, the control unit 32 monitors, for example, the SNR of the signal received by the switch unit 31 via each communication port 34 based on the SNR information received from the switch unit 31, and updates the status information indicating the monitoring result.

For example, when the monitored SNR satisfies the predetermined condition C1, the control unit 32 acquires the reception signal quality of the communication port 34 in the other switch device 101 and the SNR table ST1.

Here, the predetermined condition C1 is, for example, when the monitored SNR is lower than the corresponding threshold Th1, when the monitored SNR may be lower than the corresponding threshold Th1, and when the monitored condition is monitored. This is the case, for example, when the state in which the existing SNR is smaller than the corresponding threshold value Th1 continues for a predetermined time.

For example, when there is an SNR that satisfies the predetermined condition C1, the control unit 32 starts the following switching process.

Hereinafter, the switching process performed by the control unit 32 of the switch device 101A will be described, but the same switching process is performed by the control unit 32 of the switch devices 101B and 101C.

Here, for example, it is assumed that the SNR of the reception signal of the communication port 34B in the switch device 101A satisfies the predetermined condition C1 (see FIG. 3).

Further, it is assumed that the Ethernet frame exchanged between the switch devices 101A and 101C is performed via the communication port 34B in the switch device 101A and the communication port 34A in the switch device 101C.

Therefore, the ports used in the switch devices 101A and 101C are the communication ports 34B and 34A, respectively.

Hereinafter, the route between the switch device 101A and the switch device 101C that passes through the communication port 34B in the switch device 101A and the communication port 34A in the switch device 101C is also referred to as a use route.

In the switch device 101A, the control unit 32 passes the communication port 34A in the switch device 101A, the communication ports 34A and 34B in the switch device 101B, and the communication port 34B in the switch device 101C based on the route information in the storage unit 33. The route between the device 101A and the switch device 101C is recognized as an alternative route.

Then, the control unit 32 creates a health check packet HCP1 including, as a source address and a destination address, an address corresponding to the communication port 34B in the switch device 101A and an address corresponding to the communication port 34A in the switch device 101C, respectively.

Similarly, the control unit 32 creates a health check packet HCP2 including an address corresponding to the communication port 34A in the switch device 101A and an address corresponding to the communication port 34B in the switch device 101C as the source address and the destination address, respectively. ..

The control unit 32 transmits the created health check packets HCP1 and HCP2 via the communication ports 34B and 34A, respectively.

In the switch device 101B, when the control unit 32 receives the health check packet HCP2 from the switch device 101A via the communication port 34A and the switch unit 31, the SNR at the time of reception, the address of the communication port 34A, the temperature Ta, and the corresponding SNR table. ST1 is written in the data field in the health check packet HCP2. Then, the control unit 32 transmits the health check packet HCP2 via the switch unit 31 and the communication port 34B.

In the switch device 101C, when the control unit 32 receives the health check packet HCP2 from the switch device 101B via the communication port 34B and the switch unit 31, the SNR at the time of reception, the address corresponding to the communication port 34B, the temperature Ta, and the corresponding The SNR table ST1 is written in the data field of the health check packet HCP2.

Then, the control unit 32 rewrites the source address and the destination address of the health check packet HCP2 to the address corresponding to the communication port 34B in the switch device 101C and the address corresponding to the communication port 34A in the switch device 101A, respectively, The health check packet HCP2 is transmitted via the switch unit 31 and the communication port 34B.

In the switch device 101B, when the control unit 32 receives the health check packet HCP2 from the switch device 101C via the communication port 34B and the switch unit 31, the SNR at the time of reception, the address corresponding to the communication port 34B, the temperature Ta, and the corresponding The SNR table ST1 is written in the data field of the health check packet HCP2. Then, the control unit 32 transmits the health check packet HCP2 via the switch unit 31 and the communication port 34A.

Further, in the switch device 101C, when the control unit 32 receives the health check packet HCP1 from the switch device 101A via the communication port 34A and the switch unit 31, the SNR at the time of reception, the address corresponding to the communication port 34A, the temperature Ta, and The corresponding SNR table ST1 is written in the data field of the health check packet HCP1.

Then, the control unit 32 rewrites the source address and the destination address of the health check packet HCP1 to the address corresponding to the communication port 34A in the switch device 101C and the address corresponding to the communication port 34B in the switch device 101A, respectively, The health check packet HCP1 is transmitted via the switch unit 31 and the communication port 34A.

In the switch device 101A, the control unit 32 receives the health check packet HCP2 via the communication port 34A and the switch unit 31, and receives the health check packet HCP1 via the communication port 34B and the switch unit 31.

The control unit 32 performs the switching process further based on, for example, the acquired SNR of the communication port 34 in the other switch device 101, the temperature Ta, and the SNR table ST1.

More specifically, the control unit 32 determines, based on the contents respectively written in the data fields of the health check packets HCP1 and HCP2, which of the use route and the alternative route has better communication quality.

Specifically, the control unit 32 scores the communication quality of the use route by, for example, collecting the difference between the SNR at the time of receiving the health check packet HCP2 on the use route and the threshold Th1 corresponding to the temperature Ta. To do.

Similarly, the control unit 32 scores the communication quality of the alternative route by, for example, collecting the difference between the SNR at the time of receiving the health check packet HCP1 on the alternative route and the threshold Th1 corresponding to the temperature Ta.

When the score of the use route is equal to or higher than the score of the alternative route, the control unit 32 determines that the communication quality of the use route is superior to the communication quality of the alternative route, and keeps the use port as the communication port 34B. to decide.

On the other hand, when the score of the use route is smaller than the score of the alternative route, the control unit 32 determines that the communication quality of the alternative route is higher than the communication quality of the use route, and changes the use port from the communication port 34B to the communication port 34A. Determine that you should switch.

Then, the control unit 32 creates the routing information including the fact that the Ethernet frame transmitted from the in-vehicle communication devices 111A to 111C should be transmitted to the switch device 101C via the switch device 101B, and the created routing information is switched to the switch device. Output to the unit 31.

Further, the control unit 32 records the processing content in a log every time the switching processing is performed, for example.

[motion]
Each device in the in-vehicle communication system 301 includes a computer, and an arithmetic processing unit such as a CPU in the computer reads and executes a program including some or all of each step of the following sequence diagram or flowchart from a memory not shown and executes the program. To do. The programs of these plural devices can be installed from the outside. The programs of these plural devices are distributed in the state of being stored in the recording medium.

FIG. 5 is a flowchart defining an operation procedure when the switch device in the monitoring system according to the first embodiment of the present invention performs a switching process.

Referring to FIG. 5, first, the switch device 101 waits until it receives an Ethernet frame from another device (NO in step S102).

Then, when the switching device 101 receives the Ethernet frame from another device (YES in step S102), the switching device 101 measures the SNR of the received signal of the Ethernet frame (step S104).

Next, when the measured SNR of the received signal satisfies the predetermined condition C1 (YES in step S106), the switch device 101 transmits the health check packet to the other switch device 101, so that the SNR of the other switch device 101 is increased. , Temperature Ta and the SNR table ST1 are acquired (step S108).

Next, the switching device 101 performs the switching process based on the SNR of the received signal of itself, the temperature Ta and the SNR table ST1, and the SNR of the other switching device 101, the temperature Ta and the SNR table ST1 (step S110).

Next, when determining that the used port should be switched to the other communication port 34 (YES in step S112), the switch device 101 switches the used port to the other communication port 34 (step S114).

Next, the switch device 101 determines whether the measured SNR of the received signal does not satisfy the predetermined condition C1 (NO in step S106) or determines that the used port should be switched to another communication port 34 (NO in step S112). Alternatively, when the used port is switched to the other communication port 34 (step S114), the process waits until a new Ethernet frame is received from another device (NO in step S102).

Although the on-vehicle communication system according to the first embodiment of the present invention is configured to include the switch devices 101A, 101B, 101C, the present invention is not limited to this. The vehicle-mounted communication system 301 may be configured to include four or more switch devices 101.

Further, although the switch device according to the first exemplary embodiment of the present invention is configured to include three or more communication ports 34, the present invention is not limited to this. The switch device 101 may be configured to include two communication ports 34.

Further, in the switch device according to the first exemplary embodiment of the present invention, the control unit 32 controls the SNR of the reception signal of the used port, the temperature Ta and the SNR table ST1, and the reception of each communication port 34 in the other switch device 101. The configuration is such that the switching process is performed based on the SNR of the signal, the temperature Ta, and the SNR table ST1, but the configuration is not limited to this. The control unit 32 may be configured to perform the switching process based on the SNR of the reception signal of the used port. Specifically, the control unit 32 performs the switching process, for example, based on the magnitude relationship between the SNR of the received signal of the used port and a predetermined threshold value. Further, the control unit 32 may be configured to perform the switching process based on the SNR of the reception signal of the used port, the temperature Ta, and the SNR table ST1.

Further, in the switch device according to the first exemplary embodiment of the present invention, the SNR table ST1 is registered in the storage unit 33 for each communication port 34, but the configuration is not limited to this. The switch device 101 may have a configuration in which the common SNR table ST1 for each communication port 34 is registered in the storage unit 33.

Further, although the switch device according to the first embodiment of the present invention is configured to use the temperature Ta of the substrate 36 for the switching process, the present invention is not limited to this. In the switch device 101, the temperature of the control unit 32, the temperature of the switch unit 31, and the like may be used for the switching process.

By the way, for example, a configuration in which the redundant configuration described in Patent Document 1 is applied to an in-vehicle network is conceivable. However, in a vehicle, noise sources such as an engine and a motor may be placed close to the signal line because of space limitations.

With such an arrangement, the communication environment deteriorates rapidly in accordance with the operation of the noise source, so that the noise level of the signal transmitted through the signal line, for example, rises sharply and the communication quality deteriorates. In this case, communication may be difficult, which is not preferable. There is a demand for a technology capable of appropriately performing redundant switching in an in-vehicle network according to the communication environment.

On the other hand, the vehicle-mounted communication system according to the first embodiment of the present invention is installed in a vehicle. Each of the switch devices 101A, 101B and 101C has communication ports 34A and 34B. The communication ports 34A and 34B of the switch device 101A are connected to the communication port 34A of the switch device 101B and the communication port 34A of the switch device 101C, respectively. The communication port 34B of the switch device 101B and the communication port 34B of the switch device 101C are connected. Each of the switch devices 101A, 101B, and 101C measures the received signal quality of its own communication port 34A and the received signal quality of its own communication port 34B. Then, each of the switch devices 101A, 101B, and 101C uses the communication port 34A and 34B of its own based on the received signal quality of the communication port 34 selected as the communication port 34 to be used, and uses the other communication ports. A switching process is performed to determine whether to switch to the port 34.

In this way, each switch device 101 is configured to measure the received signal quality of the communication ports 34A and 34B. For example, when a decrease in the received signal quality due to an increase in the noise level of the signal of the used port is detected, It is possible to appropriately determine that the communication port 34 should be switched to the other communication port 34 and switch the used port to the other communication port 34. As a result, it is possible to appropriately perform the redundant switching for switching the communication route passing through the used port to the communication route passing through the other communication port 34, so that it is possible to prevent the situation where the communication is difficult from continuing. it can. Therefore, the redundant switching in the vehicle-mounted network can be appropriately performed.

In addition, in the vehicle-mounted communication system according to the first embodiment of the present invention, each of the switch devices 101A, 101B, and 101C has a corresponding relationship between its own plurality of temperatures Ta and the determination reference in the switching process for the received signal quality. Hold. Then, each of the switch devices 101A, 101B, and 101C acquires its own temperature and performs switching processing based on the acquired temperature and the corresponding relationship.

With such a configuration, for example, when the lower limit of the SNR capable of favorably performing signal processing of the received signal changes according to the temperature, the determination criterion according to the temperature of the switch device 101 is acquired from the above correspondence. can do. This makes it possible to determine that the port to be used should be switched to another communication port 34, for example, when it is difficult to perform the signal processing well.

Moreover, in the vehicle-mounted communication system according to the first embodiment of the present invention, each of the switch devices 101A, 101B, and 101C holds a correspondence relationship for each communication port 34.

With such a configuration, for example, when the lower limit temperature change of the SNR capable of favorably performing the signal processing of the received signal is different for each communication port 34, the temperature of the switch device 101 and the communication port 34 are separately determined. The judgment standard can be obtained from the above correspondence.

Moreover, in the vehicle-mounted communication system according to the first embodiment of the present invention, each of the switch devices 101A, 101B, and 101C acquires and acquires the reception signal quality and the correspondence relationship of the communication port 34 in the other switch device 101. The switching process is further performed based on the received signal quality and the corresponding relationship.

With such a configuration, it is possible to determine whether or not the signal processing of the reception signal in the other switch device 101 is favorably performed, and thus the target switch device 101 is reached via the other switch device 101. It is possible to comprehensively determine the superiority or inferiority of the communication path and the communication path to the target switch device 101 without passing through the other switch device 101.

Moreover, the switch device 101 according to the first embodiment of the present invention is mounted on a vehicle. The switch unit 31 measures the received signal quality of the plurality of communication ports 34. Then, the control unit 32 determines whether to switch the used port to another communication port 34 based on the reception signal quality of the used port selected as the communication port 34 to be used, which is measured by the switch unit 31. A switching process for making a judgment is performed.

In this way, the switch device 101 is configured to measure the received signal quality of the signal of each communication port 34. For example, when it is detected that the received signal quality of the signal of the used port is deteriorated due to the increase of the noise level, It is possible to appropriately determine that the communication port 34 should be switched to the other communication port 34 and switch the used port to the other communication port 34. As a result, it is possible to appropriately perform the redundant switching for switching the communication route passing through the used port to the communication route passing through the other communication port 34, so that it is possible to prevent the situation where the communication is difficult from continuing. it can. Therefore, the redundant switching in the vehicle-mounted network can be appropriately performed.

Next, another embodiment of the present invention will be described with reference to the drawings. It should be noted that the same or corresponding parts in the drawings are designated by the same reference numerals and description thereof will not be repeated.

<Second Embodiment>
The present embodiment relates to an in-vehicle communication system in which a cable different from an Ethernet cable further connects between switch devices as compared with the in-vehicle communication system according to the first embodiment. The contents other than those described below are the same as those of the vehicle-mounted communication system according to the first embodiment.

FIG. 6 is a diagram showing a configuration of an in-vehicle communication system according to the second embodiment of the present invention.

Referring to FIG. 6, the in-vehicle communication system 302 includes switch devices 102A, 102B, 102C. Hereinafter, each of the switch devices 102A, 102B, and 102C is also referred to as a switch device 102.

The operations of the in-vehicle communication device 111, the out-of-vehicle communication device 112, the central gateway 113, and the control device 114 shown in FIG. 6 are the same as those of the in-vehicle communication device 111, the out-of-vehicle communication device 112, the central gateway 113, and the control device 114 shown in FIG. 1, respectively. is there.

The communication ports 34 of the switch device 102A, the switch device 102B, and the switch device 102C are connected by the Ethernet cable 10, for example.

Further, the switch device 102A, the switch device 102B, and the switch device 102C are further connected by a cable for serial communication (hereinafter, also referred to as a serial cable) 11, for example.

[Configuration of switch device 102]
FIG. 7: is a figure which shows the structure of the switch apparatus in the vehicle-mounted communication system which concerns on the 2nd Embodiment of this invention.

Referring to FIG. 7, the switch device 102 includes a switch unit (measurement unit) 31, a control unit (switching processing unit) 42, a storage unit 33, a plurality of communication ports 34, and a temperature sensor 35.

The operations of the switch unit 31, storage unit 33, communication port 34, and temperature sensor 35 in the switch device 102 are the same as those of the switch unit 31, storage unit 33, communication port 34, and temperature sensor 35 in the switch device 101 shown in FIG. is there.

The serial cable 11 is connected to the control unit 42. More specifically, the control unit 42 is connected to the control unit 42 in another switch device 102 via the serial cable 11.

The control unit 42 performs serial communication with the control unit 42 in another switch device 102 via the serial cable 11.

Specifically, the control unit 42 transmits the status information in the storage unit 33, the switching Ta information including the temperature Ta and the SNR table ST1 to the other switch device 102 via the serial cable 11, and the other switch device 102. The switching determination information is acquired from the other switch device 102 via the serial cable 11.

More specifically, for example, when the SNR of the monitoring target indicated by the status information satisfies the predetermined condition C1, the control unit 42 acquires the switching determination information from another switch device 102 via the serial cable 11.

The control unit 42 performs the switching process based on, for example, the switching determination information of the own switching device 102 and the switching determination information acquired from the other switching device 102.

As described above, in the vehicle-mounted communication system according to the second embodiment of the present invention, the communication ports of the switch devices 102A, 102B, and 102C are connected by the Ethernet communication cable. The switch devices 102A, 102B, and 102C are further connected by a cable for serial communication.

With such a configuration, the reception signal quality of the communication port 34 and the corresponding relationship in the other switch device 102 can be reliably obtained from the dedicated cable for serial communication, so that the switching process can be performed quickly.

Other configurations and operations are similar to those of the vehicle-mounted communication system according to the first embodiment, and therefore detailed description will not be repeated here.

Note that it is possible to appropriately combine some or all of the constituent elements and operations of the respective devices according to the first and second embodiments of the present invention.

It should be considered that the above-described embodiments are illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

The above description includes the following additional features.

[Appendix 1]
An in-vehicle communication system mounted on a vehicle,
Each comprising a first switch device, a second switch device and a third switch device having a first communication port and a second communication port,
A first communication port and a second communication port of the first switch device are respectively connected to a first communication port of the second switch device and a first communication port of the third switch device,
A second communication port of the second switch device and a second communication port of the third switch device are connected,
Each of the first switching device, the second switching device, and the third switching device measures the reception signal quality of its own first communication port and the reception signal quality of its own second communication port. ,
Each of the first switching device, the second switching device, and the third switching device is selected as a communication port to be used from its own first communication port and second communication port. Based on the received signal quality of the used port, perform a switching process to determine whether to switch the used port to another communication port,
Each of the first switch device, the second switch device, and the third switch device has an SNR (Signal-to-Noise Ratio) of its own first communication port and an SNR of its own second communication port. An in-vehicle communication system that measures SNR and performs the switching process based on the SNR of the used port.

[Appendix 2]
A switch device mounted on a vehicle,
Multiple communication ports,
A measuring unit that measures the received signal quality of each of the communication ports,
Based on the received signal quality of the used port selected as the communication port to be used, which is measured by the measurement unit, a switching process is performed to determine whether to switch the used port to another communication port. With a switching processing unit,
The measurement unit measures the SNR of each of the communication ports,
The switching device is a switch device that performs the switching process based on the SNR of the used port.

10 Ethernet cable 11 Serial cable 31 Switch section (measurement section)
32 control unit (switching processing unit)
33 storage unit 34 communication port 35 temperature sensor 36 substrate 42 control unit (switching processing unit)
101,102 Switch device 111 In-vehicle communication device 112 Out-of-vehicle communication device 113 Central gateway 114 Control device 301,302 In-vehicle communication system

Claims (4)

An in-vehicle communication system mounted on a vehicle,
Each comprising a first switch device, a second switch device and a third switch device having a first communication port and a second communication port,
A first communication port and a second communication port of the first switch device are respectively connected to a first communication port of the second switch device and a first communication port of the third switch device,
A second communication port of the second switch device and a second communication port of the third switch device are connected,
Each of the first switching device, the second switching device, and the third switching device measures the reception signal quality of its own first communication port and the reception signal quality of its own second communication port. , And obtain the received signal quality of the communication port in other switch device,
Each of the first switch device, the second switch device, and the third switch device is selected as a communication port to be used from its own first communication port and second communication port. An in-vehicle communication system that performs a switching process for determining whether to switch the used port to another communication port based on the received signal quality of the used port and the received signal quality of the communication port in the other switch device . Each of the first switching device, the second switching device, and the third switching device includes its own port and another switching device if the received signal quality of the used port satisfies a predetermined condition. The received signal quality of the communication port of the switch device in the use route to the target switch device and the received signal of the communication port of the switch device in the alternative route between itself and the target switch device including the other communication port The vehicle-mounted communication system according to claim 1, wherein the switching process is performed based on quality. A switch device mounted on a vehicle,
Multiple communication ports,
A measuring unit that measures the reception signal quality of each of the communication ports , and acquires the reception signal quality of the communication port in another switch device ,
Based on the received signal quality of the used port selected as the communication port to be used, which is measured by the measuring unit, and the received signal quality of the communication port in the other switch device, which is acquired by the measuring unit. A switch processing unit that performs a switching process for determining whether to switch the used port to another communication port. A vehicle-mounted communication method in a vehicle-mounted communication system, comprising:
The in-vehicle communication system includes a first switch device, a second switch device, and a third switch device each having a first communication port and a second communication port,
A first communication port and a second communication port of the first switch device are respectively connected to a first communication port of the second switch device and a first communication port of the third switch device,
A second communication port of the second switch device and a second communication port of the third switch device are connected,
Each of the first switching device, the second switching device, and the third switching device measures the reception signal quality of its own first communication port and the reception signal quality of its own second communication port. Steps,
Each of the first switch device, the second switch device, and the third switch device acquiring the reception signal quality of a communication port in another switch device;
Each of the first switch device, the second switch device, and the third switch device selects one of its own first communication port and second communication port as a communication port to be used. A step of performing a switching process to determine whether to switch the used port to another communication port based on the received signal quality of the used port and the received signal quality of the communication port in the other switch device; Communication method.

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