JP7744265B2 - In-vehicle communication device and in-vehicle communication method - Google Patents

Description

The present invention relates to an in-vehicle communication device and an in-vehicle communication method.

In-vehicle Ethernet technology has been proposed for in-vehicle communications, applying Ethernet (registered trademark), a communication standard for wired LANs (Local Area Networks). Patent Document 1 discloses an in-vehicle repeater that applies in-vehicle Ethernet to an in-vehicle communication system. The in-vehicle repeater disclosed in Patent Document 1 configures the physical layer, data link layer, and network layer of the OSI reference model using hardware, reducing communication delays and heat generation.

JP 2019-106584 A

When communication quality deteriorates in the in-vehicle communication system disclosed in Patent Document 1, there are various causes of errors that result in the deterioration of communication quality, making it difficult to identify the error and improve communication quality in the in-vehicle Ethernet. Therefore, when communication quality deteriorates in the in-vehicle Ethernet, communication packets are discarded, and if this does not improve communication quality, communication will eventually be interrupted.

The present invention was made in consideration of the problems inherent in the prior art. The object of the present invention is to provide an in-vehicle communication device that can improve communication quality when the communication quality of an in-vehicle network deteriorates.

An in-vehicle communication device according to one aspect of the present invention is an in-vehicle communication device capable of communicating with an ECU (Electronic Control Unit) mounted on a vehicle, and includes a communication path setting unit that sets either a first communication unit or a second communication unit as a communication path for communicating with the ECU; a quality information acquisition unit that acquires communication quality information of the communication path; a communication quality determination unit that determines whether the communication quality of the communication path is good based on the quality value of the communication quality information; and a communication speed setting unit that lowers the communication speed of the communication path if the quality value of the communication quality information is lower than a predetermined value. The communication path setting unit sets either the first communication unit or the second communication unit as the communication path if the quality value of the communication quality information is lower than the predetermined value for the communication path in which the communication speed has been lowered.

Another aspect of the present invention is an in-vehicle communication method executed by a computer, which sets either a first communication unit or a second communication unit as a communication path for communicating with an ECU mounted on the vehicle, acquires communication quality information of the communication path, determines whether the communication quality of the communication path is good based on the quality value of the communication quality information, reduces the communication speed of the communication path if the quality value of the communication quality information is lower than a predetermined value, and sets the other of the first communication unit or the second communication unit as the communication path if the quality value of the communication quality information for the communication path with the reduced communication speed is lower than the predetermined value.

The present invention provides an in-vehicle communication device that can improve communication quality when the communication quality of an in-vehicle network deteriorates.

1 is a diagram showing a configuration of an in-vehicle communication system according to an embodiment of the present invention; 1 is a diagram illustrating a configuration of an in-vehicle communication device according to an embodiment of the present invention. 10 is a diagram showing an example of a correspondence relationship between SQI of quality information and SNR in the present embodiment. FIG. FIG. 3 is a diagram for explaining an example of processing performed by the in-vehicle communication device according to the embodiment. FIG. 3 is a diagram for explaining an example of processing performed by the in-vehicle communication device according to the embodiment. FIG. 3 is a diagram for explaining an example of processing performed by the in-vehicle communication device according to the embodiment. FIG. 3 is a diagram for explaining an example of processing performed by the in-vehicle communication device according to the embodiment. 5A and 5B are diagrams for explaining the influence of noise on the in-vehicle communication device according to the embodiment. 4 is a flowchart illustrating an example of processing performed by the in-vehicle communication device according to the present embodiment.

The in-vehicle communication system 10 according to this embodiment will be described in detail below using the drawings. Note that the dimensional proportions in the drawings have been exaggerated for the sake of explanation and may differ from the actual proportions. In addition, in the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

(General configuration of in-vehicle communication system 10)
Fig. 1 is a diagram showing a schematic configuration of an in-vehicle communication system 10 according to this embodiment. As shown in Fig. 1, the in-vehicle communication system 10 includes an in-vehicle communication device 100, a switch 200, a display unit 300, and an ECU 400, which is an electronic control unit (ECU) mounted on the vehicle.

The in-vehicle communication device 100 is a device capable of communicating with the ECU 400. In the in-vehicle communication system 10, communication takes place between the in-vehicle communication device 100 and the ECU 400 via a switch 200. In the in-vehicle communication system 10, communication takes place via Ethernet (registered trademark) for intra-vehicle communication. The in-vehicle communication device 100 is connected to a connector 201 of the switch 200 and a connector 301 of the display unit 300 via a connector 101.

Vehicles such as automobiles are equipped with many sensors and devices such as actuators that convert electrical signals into motion, and ECUs 400 perform control based on data obtained from these sensors and devices. Vehicles are also equipped with various types of ECUs 400, and in-vehicle networking is advancing to enable cooperative control between these ECUs 400. In-vehicle networks employ in-vehicle Ethernet technology, which applies Ethernet (registered trademark), a communications standard for wired LANs (Local Area Networks).

In the case of in-vehicle Ethernet, the communication standard 100BASE-T1 (IEEE 802.3bw) specifies a communication speed of 100 Mbps. The communication standard 1000BASE-T1 (IEEE 802.3bp) specifies a communication speed of 1 Gbps. Furthermore, the communication standard 10BASE-T1L (IEEE 802.3cg) specifies a communication speed of 10 Mbps. In the in-vehicle communication system 10 of this embodiment, an example is shown in which the communication speeds of the first communication unit 130 and the second communication unit 140 are 100 Mbps and 1 Gbps, respectively. However, a configuration in which the communication speeds of 10 Mbps and 100 Mbps are used may also be used.

The in-vehicle communication device 100 communicates with the ECU 400 via the switch 200. The in-vehicle communication device 100 also includes a control unit 110, a memory unit 120, a first communication unit 130, a second communication unit 140, a low-speed communication unit 150, and a detection unit 160. Details of the in-vehicle communication device 100 will be described later.

The switch 200 registers the MAC address in an internal register within the switch 200, and selects either the first communication unit 130 or the second communication unit 140 based on the registered MAC address to communicate with the ECU 400.

The display unit 300 is connected to the low-speed communication unit 150 in the in-vehicle communication device 100 via connector 101 and connector 301. In this embodiment, the display unit 300 displays a warning if there is an abnormality in communication on the communication path.

An ECU 400 generally consists of a computer and its peripheral devices (such as a communication module). A single vehicle may be equipped with multiple ECUs 400 for different purposes, such as engine control, brake control, and safety control. These functions are realized by software built into the ECUs 400. As mentioned above, each ECU 400 communicates with the other ECUs via an in-vehicle network.

(Configuration of in-vehicle communication device 100)
Next, the configuration of the in-vehicle communication device 100 will be described in detail.

The control unit 110 executes the functions shown in Figure 2. The control unit 110 also sets up a communication path based on the SQI (Signal Quality Index/Indicator) value acquired by the detection unit 160 (described below).

The storage unit 120 stores the set communication path information as data. The storage unit 120 may also store programs for each function executed by the control unit 110. The communication path information and programs stored in the storage unit 120 may be configured as physically or logically separated areas within a single storage device. Alternatively, the storage unit 120 for each data item may be configured in multiple physically separate storage devices.

The first communication unit 130 is a communication path for communicating with the ECU 400, and uses Ethernet communication. Specifically, communication takes place at the physical layer and data link layer of the OSI reference model. In this embodiment, the communication speed of the first communication unit 130 is 1 Gbps or 100 Mbps.

The second communication unit 140 uses Ethernet communication, just like the first communication unit 130. The second communication unit 140 has the same configuration as the first communication unit 130. Either the first communication unit 130 or the second communication unit 140 is set by the switch 200 as the communication path for communication with the ECU 400.

The low-speed communication unit 150 is connected to the display unit 300 via connectors 101 and 301 via a communication path compatible with protocols such as CAN (Controller Area Network). The communication speed of the low-speed communication unit 150 is slower than the communication speeds of the first communication unit 130 and the second communication unit 140, and in this embodiment, a maximum communication speed of 1 Mbps is achieved.

The detection unit 160 acquires the SQI of the communication path and sends it to the control unit 110. The SQI is an index indicating communication quality and is defined, for example, as one of eight levels ranging from 0 to 7, as shown in FIG. 3. The SQI level is determined according to the SNR (Signal-to-Noise Ratio), as shown in FIG. 3. The detection unit 160 acquires the SQI of the communication path at a predetermined timing. The predetermined timing for acquiring the SQI is, for example, at intervals of 100 ms. Note that the predetermined timing for acquiring the SQI is not limited to the configuration of the embodiment, and may be acquired at intervals longer or shorter than 100 ms. The SQI is a value acquired as information regarding the communication path of an in-vehicle network in existing systems. In other words, the in-vehicle communication device 100 does not require the addition of a new device for acquiring the quality of the communication path, and its implementation can achieve smaller device size and lower power consumption.

(Functional configuration of in-vehicle communication device 100)
Fig. 2 is a block diagram showing the functional configuration of the in-vehicle communication device 100. As shown in Fig. 2, the control unit 110 of the in-vehicle communication device 100 includes, as its functions, a communication path setting unit 111, a quality information acquisition unit 112, a communication quality determination unit 113, a communication speed setting unit 114, and a warning display control unit 115. The storage unit 120 stores communication path information in a communication path information DB 121. The storage unit 120 may also include information defining communication quality levels as shown in Fig. 3 as a communication quality information DB 122.

The communication path setting unit 111 sets either the first communication unit 130 or the second communication unit 140 as the communication path for communication with the ECU 400. Specifically, the communication path setting unit 111 sets either the first communication unit 130 or the second communication unit 140 as the communication path by updating a MAC address table (not shown) provided in the switch 200. In this embodiment, the communication path setting unit 111 sets the first communication unit 130 as the communication path in the initial state of the in-vehicle communication device 100.

Furthermore, when the quality value of the communication quality information for a communication path in which the communication speed has been lowered by the communication speed setting unit 114 (described below) is lower than a predetermined value, the communication path setting unit 111 sets the other of the first communication unit 130 and the second communication unit 140 as the communication path. In this embodiment, when the first communication unit 130 is set as the initial state of the in-vehicle communication device 100, the other of the first and second communication units corresponds to the second communication unit 140.

The quality information acquisition unit 112 acquires communication quality information for the communication path. Specifically, the quality information acquisition unit 112 acquires the SQI information detected by the detection unit 160 as communication quality information. More specifically, the SQI shown in Figure 3 is acquired as communication quality information. Note that SQI levels 0 to 7 correspond to the quality values of the communication quality information.

The communication quality determination unit 113 determines whether the communication quality of the communication path is good or not based on the quality value of the communication quality information. Specifically, the communication quality determination unit 113 determines whether the communication quality of the communication path is good or not based on whether the SQI level is less than 1, based on the communication quality information acquired by the quality information acquisition unit 112.

The communication speed setting unit 114 reduces the communication speed of the communication path when the quality value of the communication quality information is lower than a predetermined value. Specifically, when the SQI, which corresponds to the quality value of the communication quality information, is lower than 1, the communication speed setting unit 114 reduces the communication speed of the communication path by a factor of 10. In this embodiment, when 1 Gbps is applied as the initial value of the communication speed of the communication path, the communication speed setting unit 114 reduces the communication speed of the communication path to 100 Mbps when the quality value of the communication quality information is lower than a predetermined value. Furthermore, when 100 Mbps is applied as the initial value of the communication speed of the communication path, the communication speed setting unit 114 reduces the communication speed of the communication path to 10 Mbps when the quality value of the communication quality information is lower than a predetermined value.

Figures 4A to 4D are diagrams for explaining the relationship between various communication qualities and communication speeds of communication paths, divided into "Case 1" to "Case 4." In Figure 4A, at time T1, the communication quality (SQI) of the communication path set by the first communication unit 130 is assumed to be 0. In this case, the communication quality determination unit 113 determines that the quality of the communication path is not good because the SQI is less than 1. Thereafter, the communication speed setting unit 114 reduces the communication speed of the first communication unit 130 set as the communication path to 100 Mbps, which is one-tenth of 1 Gbps. As a result, in the example shown in Figure 4A, the SQI, which indicates communication quality, improves to 5 at time T2.

In Figure 4B, "Case 2" shows an example in which the SQI, which indicates communication quality, remains at 0 at time T2 and the communication quality does not improve. In this case, the communication path setting unit 111 sets the communication path to the second communication unit 140. In the example shown in Figure 4B, at time T3, the SQI, which indicates communication quality, improves to 7 for the communication path set to the second communication unit 140.

In the example shown in Figure 4C, at time T3, the SQI, which indicates the communication quality of the communication path set by the second communication unit 140, remains at 0, and an example in which the communication quality does not improve is shown as "Case 3." In this case, the communication speed setting unit 114 reduces the communication speed of the second communication unit 140 set as the communication path to 100 Mbps, which is one-tenth of 1 Gbps. As a result, in the example shown in Figure 4C, the SQI, which indicates the communication quality, improves to 3 at time T4.

In the example shown in Figure 4D, at time T4, the SQI, which indicates communication quality, remains at 0, and an example in which communication quality does not improve is shown as "Case 4." In this case, the warning display control unit 115 displays a warning on the display unit 300. Details of the warning display control unit 115 will be described later.

As described above, in this embodiment, when the SQI, which indicates the communication quality of the communication path, is less than 1, the communication speed setting unit 114 reduces the communication speed of the communication path to one-tenth of the original speed. As shown in FIG. 5, this is an effective means of improving communication quality when, for example, the communication quality of the communication path is reduced due to noise or the like, reducing the communication speed makes it possible to communicate without being affected by the noise. Here, noise that affects the communication path corresponds to, for example, noise in the car radio frequency band.

In addition, in this embodiment, if the communication quality does not improve after the communication speed of the communication path is reduced, an example is shown in which the communication path is switched from the first communication unit 130 to the second communication unit 140. This is an effective means of improving communication quality in the event of a physical communication path malfunction (failure), such as a fixed path failure caused by, for example, a broken electric wire (communication line) or an increase in the interference resistance value of a connector fitting.

When communication is not possible on all communication paths during Ethernet communication at the data link layer, the warning display control unit 115 displays a warning on the display unit 300 to alert the user. Specifically, the warning display control unit 115 displays a warning on the display unit 300 when the quality value is lower than a predetermined value on both the communication path for which the first communication unit 130 has been set and the communication speed has been reduced, and the communication path for which the second communication unit 140 has been set and the communication speed has been reduced. This makes it possible to alert the user if the quality of the communication path does not improve.

The warning display control unit 115 also displays a warning on the display unit 300 via the low-speed communication unit 150. As described above, the low-speed communication unit 150 is implemented using a communication standard that allows low-speed communication, such as CAN. The low-speed communication unit 150 corresponds to the third communication unit. This low-speed communication unit 150 communicates at a speed slower than the normal communication speed of the first communication unit 130 and the second communication unit 140 and the communication speed when the communication speed is lowered by the communication speed setting unit 114. In this embodiment, as described above, the normal communication speed of the first communication unit 130 and the second communication unit 140 is 1 Gbps, and the communication speed when the communication speed is lowered by the communication speed setting unit 114 is 100 Mbps. In contrast, the low-speed communication unit 150 communicates with the display unit 300 at, for example, 1 Mbps. With this configuration, communication between the low-speed communication unit 150 and the display unit 300 is significantly slower than the communication speed of the first communication unit 130 and the second communication unit 140, making it possible to reliably display a warning on the display unit 300.

(Outline of processing flow of in-vehicle communication device 100)
Next, the flow of processing in the in-vehicle communication device 100 will be shown using the flowchart shown in Figure 6. The series of operations of the in-vehicle communication device 100 shown in the flowchart of Figure 6 starts when the in-vehicle communication device 100 is started, and ends when the operation is completed. The processing in the flowchart shown in Figure 6 also ends when the power is turned off or an interrupt occurs to end the processing. In addition, in the following description of the flowchart, content that is the same as the content described in the above-mentioned description of the in-vehicle communication system 10 and the in-vehicle communication device 100 will be omitted or simplified.

In step S601, the communication path setting unit 111 sets the first communication unit 130 as a communication path for communication with the ECU 400.

In step S602, the quality information acquisition unit 112 acquires communication quality information of the communication path. Specifically, the quality information acquisition unit 112 acquires the SQI information detected by the detection unit 160 as communication quality information.

In step S603, the communication quality determination unit 113 determines whether the communication quality of the communication path is good based on the quality value of the communication quality information. Specifically, the communication quality determination unit 113 determines whether the SQI is less than 1 based on the communication quality information acquired by the quality information acquisition unit 112. In step S603, if the communication quality determination unit 113 determines that the SQI is less than 1 (step S603: YES), the process proceeds to step S604. On the other hand, in step S603, if the communication quality determination unit 113 determines that the SQI is not less than 1 (step S603: NO), the process returns to step S602, and the process from step S602 is repeated.

In step S604, the communication speed setting unit 114 reduces the communication speed of the communication path. Specifically, if it is determined in step S603 that the SQI, which corresponds to the quality value of the communication quality information, is less than 1, the communication speed setting unit 114 reduces the communication speed of the communication path to one-tenth.

In step S605, the quality information acquisition unit 112 acquires communication quality information of the communication path. Specifically, the quality information acquisition unit 112 acquires the SQI information detected by the detection unit 160 as communication quality information. In step S605, the SQI information after the communication speed has been reduced by the communication speed setting unit 114 is acquired as communication quality information.

In step S606, the communication quality determination unit 113 determines whether the communication quality of the communication path is good based on the quality value of the communication quality information, as in step S603. Specifically, the communication quality determination unit 113 determines whether the SQI is less than 1 based on the communication quality information acquired by the quality information acquisition unit 112. In step S606, if the communication quality determination unit 113 determines that the SQI is less than 1 (step S606: YES), the process proceeds to step S607. On the other hand, in step S606, if the communication quality determination unit 113 determines that the SQI is not less than 1 (step S606: NO), the process returns to step S602, and the process from step S602 is repeated.

In step S607, the control unit 110 determines whether the second communication unit 140 is set as a communication path. If the control unit 110 determines in step S607 that the second communication unit 140 is set as a communication path (step S607: YES), the process proceeds to step S608. On the other hand, if the control unit 110 determines in step S607 that the second communication unit 140 is not set as a communication path (step S607: NO), the process proceeds to step S609.

In step S608, the warning display control unit 115 displays a warning on the display unit 300. This step S608 corresponds to the case where the quality value is lower than a predetermined value for both the communication path for which the first communication unit 130 has been set and the communication speed has been reduced, and the communication path for which the second communication unit 140 has been set and the communication speed has been reduced.

In step S609, the communication path setting unit 111 sets the second communication unit 140 as a communication path for communication with the ECU 400. Then, processing returns to step S602, and the processing from step S602 is repeated.

In the above processing flow, the communication path setting unit 111 may be configured to set the second communication unit 140 as the communication path in step S601, and to set the first communication unit 130 as the communication path in step S609. In this case, in step S607, the control unit 110 determines whether the first communication unit 130 has been set as the communication path.

As described above, the in-vehicle communication device 100 according to this embodiment includes a communication path setting unit 111, a quality information acquisition unit 112, a communication quality determination unit 113, and a communication speed setting unit 114. The communication path setting unit 111 sets either the first communication unit 130 or the second communication unit 140 as a communication path for communication with the ECU 400 installed in the vehicle. The quality information acquisition unit 112 acquires communication quality information of the communication path. The communication quality determination unit 113 determines whether the communication quality of the communication path is good based on the quality value of the communication quality information. The communication speed setting unit 114 reduces the communication speed of the communication path if the quality value of the communication quality information is lower than a predetermined value. Furthermore, if the quality value of the communication quality information for the communication path for which the communication speed has been reduced is lower than the predetermined value, the communication path setting unit 111 sets the other of the first communication unit 130 or the second communication unit 140 as the communication path.

With this configuration, when the communication quality of the communication path is degraded due to noise or the like, the in-vehicle communication device 100 can reduce the communication speed, allowing communication to be carried out without being affected by the noise. Furthermore, the in-vehicle communication device 100 can improve communication quality in the event of a physical communication path malfunction (failure), such as a route fixation failure caused by a broken wire (communication line) or an increase in the interference resistance value of a connector mating portion. In other words, the in-vehicle communication device 100 can improve communication quality when the communication quality of the in-vehicle network is degraded.

As described above, the in-vehicle communication device 100 further includes a warning display control unit 115. The warning display control unit 115 displays a warning on the display unit 300 when the quality value is lower than a predetermined value for both the communication path for which the first communication unit 130 has been set and the communication speed has been reduced, and the communication path for which the second communication unit 140 has been set and the communication speed has been reduced. This makes it possible to alert the user if the quality of the communication path does not improve.

The warning display control unit 115 also displays a warning on the display unit 300 via the low-speed communication unit 150, which is capable of communication at a slower speed than the communication path for which the first communication unit 130 and the second communication unit 140 have been set and for which the communication speed has been reduced. The low-speed communication unit 150 corresponds to the third communication unit. As a result, in the in-vehicle communication device 100, the communication speed between the low-speed communication unit 150 and the display unit 300 is significantly slower than the communication speed of the first communication unit 130 and the second communication unit 140, making it possible to reliably display a warning on the display unit 300.

Furthermore, the above-mentioned communication quality information uses SQI. This SQI is a value obtained in existing systems as information about the communication path of the vehicle's network. In other words, the in-vehicle communication device 100 does not need to be equipped with a new device for obtaining the quality of the communication path, and in its implementation, it is possible to achieve a smaller device and lower power consumption.

(Other embodiments)
Although the embodiments have been described in detail with reference to the drawings, the present embodiments are not limited to the contents described in the above embodiments. Furthermore, the components described above include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the configurations described above can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configurations can be made without departing from the spirit of the embodiments.

In the above-described embodiment, an example was described in which, if the SQI, which indicates the quality value of a communication path, is lower than 1, the communication speed of that communication path is first reduced, and if this does not improve the communication quality of the communication path, the communication path is switched. For example, the in-vehicle communication device 100 may be configured to first switch the communication path, and then reduce the communication speed if the communication quality does not improve. A configuration that switches the communication path first can be applied, for example, to locations where component malfunctions (fixed route failures) are likely to occur physically on the communication path, making it possible to more effectively improve communication quality.

Furthermore, in the above-described embodiment, a configuration has been described in which the communication quality determination unit 113 determines the quality of the communication path based on the SQI value acquired by the detection unit 160. For example, a configuration may be adopted in which the detection unit 160 acquires the SNR of the signal, calculates the SQI based on reference information in the communication quality information DB 122 in which this SNR is pre-stored, and the communication quality determination unit 113 determines the quality of the communication path. For example, the reference information may be information that compares the SQI and SNR shown in FIG. 3, and be stored in the storage unit 120 as the communication quality information DB 122 as shown in FIG. 2. For example, by allowing the user to set the SNR range for this SQI, it is possible to realize an in-vehicle communication device 100 that can accommodate a variety of communication qualities.

Furthermore, a computer program (communication program) that causes a computer to execute the processing (on-board communication method) in the above-described on-board communication device 100, and a computer-readable recording medium on which the program is recorded, are included within the scope of this embodiment. Any type of computer-readable recording medium may be used. Furthermore, the computer program is not limited to being recorded on the above-described recording medium, but may also be transmitted via a telecommunications line, a wireless or wired communication line, a network such as the Internet, or the like.

The features of the in-vehicle communication device 100 and the in-vehicle communication method are described below.

The in-vehicle communication device 100 according to the first aspect is an in-vehicle communication device capable of communicating with an ECU 400 mounted on a vehicle. The in-vehicle communication device 100 includes a communication path setting unit 111 that sets either the first communication unit 130 or the second communication unit 140 as a communication path for communication with the ECU 400. The in-vehicle communication device 100 also includes a quality information acquisition unit 112 that acquires communication quality information of the communication path. The in-vehicle communication device 100 also includes a communication quality determination unit 113 that determines whether the communication quality of the communication path is good or not based on the quality value of the communication quality information. The in-vehicle communication device 100 also includes a communication speed setting unit 114 that lowers the communication speed of the communication path when the quality value of the communication quality information is lower than a predetermined value. Furthermore, the communication path setting unit 111 sets the other of the first communication unit 130 or the second communication unit 140 as the communication path when the quality value of the communication quality information is lower than the predetermined value for the communication path for which the communication speed has been lowered.

With the above configuration, when the communication quality of the communication path is degraded due to noise or the like, the in-vehicle communication device 100 can communicate without being affected by the noise by lowering the communication speed. Furthermore, the in-vehicle communication device 100 can improve communication quality in the event of a physical communication path malfunction (failure), such as a route fixation failure caused by a broken wire (communication line) or an increase in the interference resistance value of a connector fitting. In other words, the in-vehicle communication device 100 can improve communication quality when the communication quality of the in-vehicle network is degraded.

The in-vehicle communication device 100 according to the second aspect may further include a warning display control unit 115. Furthermore, the warning display control unit 115 may display a warning on the display unit 300 when the quality value is lower than a predetermined value in both the communication path in which the first communication unit 130 is set and the communication speed is reduced, and the communication path in which the second communication unit 140 is set and the communication speed is reduced.

With the above configuration, the in-vehicle communication device 100 can warn the user if the quality of the communication path does not improve.

The warning display control unit 115 of the in-vehicle communication device 100 according to the third aspect may display a warning on the display unit 300 via a third communication unit that is capable of communication at a slower speed than the communication path for which the first communication unit 130 and the second communication unit 140 have been set and the communication speed has been reduced.

With the above configuration, the communication speed between the low-speed communication unit 150 and the display unit 300 of the in-vehicle communication device 100 is significantly slower than the communication speed between the first communication unit 130 and the second communication unit 140, making it possible to reliably display a warning on the display unit 300.

The communication quality information of the in-vehicle communication device 100 according to the fourth aspect may be an SQI (Signal Quality Index/Indicator).

With this configuration, the in-vehicle communication device 100 uses the SQI applied in existing systems, eliminating the need to install a new device to acquire the quality of the communication path, and in doing so, it is possible to achieve a smaller device and lower power consumption.

The in-vehicle communication method according to the fifth aspect is an in-vehicle communication method executed by a computer. The in-vehicle communication method sets either the first communication unit 130 or the second communication unit 140 as a communication path for communicating with an ECU 400 mounted on the vehicle. The in-vehicle communication method also acquires communication quality information of the communication path. The in-vehicle communication method also determines whether the communication quality of the communication path is good based on the quality value of the communication quality information. The in-vehicle communication method also reduces the communication speed of the communication path if the quality value of the communication quality information is lower than a predetermined value. The in-vehicle communication method also sets the other of the first communication unit or the second communication unit as the communication path if the quality value of the communication quality information is lower than the predetermined value for the communication path whose communication speed has been reduced.

With the above configuration, when the communication quality of the communication path is degraded due to noise or the like, the in-vehicle communication method reduces the communication speed, enabling communication without being affected by the noise. Furthermore, the in-vehicle communication method can improve communication quality in the event of a malfunction (failure) in the physical communication path, such as a fixed path failure caused by a broken electric wire (communication line) or an increase in the interference resistance value of a connector mating portion. In other words, when the communication quality of the in-vehicle communication method or in-vehicle network is degraded, it is possible to improve communication quality.

REFERENCE SIGNS LIST 10 In-vehicle communication system 100 In-vehicle communication device 101, 201, 301 Connector 110 Control unit 111 Communication path setting unit 112 Quality information acquisition unit 113 Communication quality determination unit 114 Communication speed setting unit 115 Warning display control unit 120 Storage unit 121 Communication path information DB
130 First communication unit 140 Second communication unit 150 Low-speed communication unit 160 Detection unit 200 Switch 300 Display unit 400 ECU

Claims (3)

An in-vehicle communication device capable of communicating with an ECU (Electronic Control Unit) mounted on a vehicle,
a communication path setting unit that sets one of the first communication unit and the second communication unit as a communication path for communicating with the ECU;
a quality information acquisition unit that acquires communication quality information of the communication path;
a communication quality determination unit that determines whether the communication quality of the communication path is good or not based on the quality value of the communication quality information;
a communication speed setting unit that reduces the communication speed of the communication path when the quality value of the communication quality information is lower than a predetermined value;
a warning display control unit ;
the communication path setting unit sets the other of the first communication unit and the second communication unit as the communication path when the quality value of the communication quality information is lower than the predetermined value in the communication path in which the communication speed has been reduced ;
The warning display control unit displays a warning on a display unit via a third communication unit that is capable of communicating at a slower speed than the communication path for which the first communication unit and the second communication unit are set and the communication speed is lowered, when the quality value of the communication quality information is lower than the predetermined value in both the communication path for which the first communication unit is set and the communication speed is lowered, and the communication path for which the second communication unit is set and the communication speed is lowered. The in-vehicle communication device according to claim 1, wherein the communication quality information is an SQI (Signal Quality Index/Indicator). 1. A computer-implemented in-vehicle communication method, comprising:
setting one of the first communication unit and the second communication unit as a communication path for communicating with an ECU mounted on the vehicle;
acquiring communication quality information of the communication path;
determining whether the communication quality of the communication path is good or not based on the quality value of the communication quality information;
If the quality value of the communication quality information is lower than a predetermined value, the communication speed of the communication path is reduced;
When the quality value of the communication quality information is lower than the predetermined value in the communication path in which the communication speed has been reduced, the other of the first communication unit and the second communication unit is set as the communication path ;
an in-vehicle communication method, wherein, when the quality value of the communication quality information is lower than the predetermined value in both the communication path in which the first communication unit is set and the communication speed is reduced, and the communication path in which the second communication unit is set and the communication speed is reduced, a warning is displayed on a display unit via a third communication unit in which the first communication unit and the second communication unit are set and which can communicate at a slower speed than the communication path in which the communication speed is reduced .