In-vehicle communication device and in-vehicle communication method

Abstract

To provide an on-vehicle communication device enabling improvement of communication quality of an on-vehicle network when the communication quality deteriorates.SOLUTION: An on-vehicle communication device 100 comprises: 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 any one of a first communication unit and a second communication unit as a communication path for performing communication with an ECU mounted on a vehicle. The quality information acquisition unit 112 acquires communication quality information of the communication path. The communication quality determination unit 113 determines whether or not communication quality is good on the basis of a quality value of the communication quality information. The communication speed setting unit reduces a communication speed of the communication path when the quality value of the communication quality information is lower than a predetermined value. Also, the communication path setting unit 111 sets the other one of the first communication unit and the second communication unit as a communication path when the quality value of the communication quality information is lower than a predetermined value.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an in-vehicle communication device and an in-vehicle communication method. [Background technology]

[0002] Conventionally, in-vehicle Ethernet technology has been proposed that applies Ethernet (registered trademark), a communication standard for wired LANs (Local Area Networks), to in-vehicle communications. 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 with hardware, thereby reducing communication delays and heat generation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-106584 Summary of the Invention [Problem to be solved by the invention]

[0004] When communication quality deteriorates in the in-vehicle communication system disclosed in Patent Document 1, it is difficult to identify the error and improve the communication quality in the in-vehicle Ethernet because there are various causes of the error that causes the deterioration of communication quality. Therefore, when communication quality deteriorates in the in-vehicle Ethernet, the system discards communication packets, and if the communication quality does not improve, communication will eventually be interrupted.

[0005] The present invention has been made in view of the problems inherent in the conventional technology, and an 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. [Means for solving the problem]

[0006] An in-vehicle communication device according to an embodiment of the present invention is an in-vehicle communication device capable of communicating with an ECU (Electronic Control Unit) installed in 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 or not 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, and the communication path setting unit 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 in the communication path in which the communication speed has been lowered.

[0007] 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 installed in the vehicle, obtains 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 is lower than the predetermined value for the communication path whose communication speed has been reduced. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an in-vehicle communication device that can improve communication quality when the communication quality of an in-vehicle network deteriorates. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing a configuration of an in-vehicle communication system according to an embodiment of the present invention; [Figure 2] 1 is a diagram illustrating a configuration of an in-vehicle communication device according to an embodiment of the present invention. [Figure 3]10 is a diagram showing an example of the correspondence between SQI and SNR of quality information in the present embodiment. FIG. [Figure 4A] FIG. 3 is a diagram for explaining an example of processing performed by the in-vehicle communication device according to the embodiment. [Figure 4B] FIG. 3 is a diagram for explaining an example of processing performed by the in-vehicle communication device according to the embodiment. [Figure 4C] FIG. 3 is a diagram for explaining an example of processing performed by the in-vehicle communication device according to the embodiment. [Figure 4D] FIG. 3 is a diagram for explaining an example of processing performed by the in-vehicle communication device according to the embodiment. [Figure 5] 5A and 5B are diagrams for explaining the influence of noise on the in-vehicle communication device according to the embodiment. [Figure 6] 4 is a flowchart illustrating an example of processing performed by the in-vehicle communication device according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] The in-vehicle communication system 10 according to this embodiment will be described in detail below with reference to the drawings. Note that the dimensional proportions in the drawings are 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.

[0011] (Schematic 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 provided in a vehicle, a switch 200, a display unit 300, and an ECU 400, which is an electronic control unit (ECU) mounted on the vehicle.

[0012] The in-vehicle communication device 100 is a device capable of communicating with the ECU 400. In the in-vehicle communication system 10, communication is performed between the in-vehicle communication device 100 and the ECU 400 via a switch 200. In the in-vehicle communication system 10, communication is performed via Ethernet (registered trademark) as communication within the vehicle. 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.

[0013] Vehicles such as automobiles are equipped with many sensors and devices such as actuators that convert electrical signals into motion, and an ECU 400 performs control based on data acquired from these sensors and devices. Furthermore, vehicles are equipped with various types of ECUs 400, and in-vehicle networking is advancing for cooperative control between these ECUs 400. In-vehicle networks employ in-vehicle Ethernet technology, which uses Ethernet (registered trademark), a communication standard for wired LANs (Local Area Networks).

[0014] In the in-vehicle Ethernet, the communication standard 100BASE-T1 (IEEE802.3bw) specifies a communication speed of 100 Mbps. The communication standard 1000BASE-T1 (IEEE802.3bp) specifies a communication speed of 1 Gbps. Furthermore, the communication standard 10BASE-T1L (IEEE802.3cg) specifies a communication speed of 10 Mbps. In the in-vehicle communication system 10 of this embodiment, an example is shown in which 100 Mbps and 1 Gbps are applied as the communication speeds of the first communication unit 130 and the second communication unit 140, but a configuration in which 10 Mbps and 100 Mbps are applied as the communication speeds may also be used.

[0015] The in-vehicle communication device 100 communicates with the ECU 400 via the switch 200. The in-vehicle communication device 100 includes a control unit 110, a storage 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.

[0016] 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 realize communication with the ECU 400.

[0017] The display unit 300 is connected to the low-speed communication unit 150 in the in-vehicle communication device 100 via the connector 101 and the connector 301. In this embodiment, the display unit 300 displays a warning when an abnormality occurs in communication on the communication path.

[0018] The ECU 400 generally comprises a computer and its peripheral devices (such as a communication module). A single vehicle is equipped with a plurality of ECUs 400 for various purposes, such as engine control, brake control, and safety control. These functions are realized by software installed in the ECUs 400. As described above, the ECUs 400 communicate with each other via an in-vehicle network.

[0019] (Configuration of in-vehicle communication device 100) Next, the configuration of the in-vehicle communication device 100 will be described in detail.

[0020] The control unit 110 executes the functions shown in Fig. 2. Furthermore, the control unit 110 sets up a communication path based on an SQI (Signal Quality Index / Indicator) value acquired by a detection unit 160 (described later).

[0021] 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 in a single storage device. Alternatively, the storage unit 120 for each data may be configured to be provided in multiple physically different storage devices.

[0022] The first communication unit 130 is a communication path for communicating with the ECU 400, and employs Ethernet communication. Specifically, communication is performed 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.

[0023] The second communication unit 140 uses Ethernet communication, similar to 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 a communication path for communication with the ECU 400.

[0024] The low-speed communication unit 150 is connected to the display unit 300 via a communication path compatible with a protocol such as CAN (Controller Area Network) via the connector 101 and the connector 301. 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, is realized at a maximum communication speed of 1 Mbps.

[0025] 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 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 an existing system. In other words, the in-vehicle communication device 100 does not need to be provided with a new device for acquiring the quality of the communication path, and in its implementation, it is possible to achieve a smaller device and lower power consumption.

[0026] (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 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 include information defining communication quality levels as shown in Fig. 3 as a communication quality information DB 122.

[0027] The communication path setting unit 111 sets either the first communication unit 130 or the second communication unit 140 as a communication path for communicating 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 a 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 an initial state of the in-vehicle communication device 100.

[0028] Furthermore, when the quality value of the communication quality information is lower than a predetermined value in a communication path in which the communication speed has been reduced by a communication speed setting unit 114 (described later), 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.

[0029] The quality information acquisition unit 112 acquires communication quality information of the communication path. Specifically, the quality information acquisition unit 112 acquires SQI information detected by the detection unit 160 as the communication quality information. More specifically, the SQI shown in Fig. 3 is acquired as the communication quality information. Note that SQI levels 0 to 7 correspond to the quality values ​​of the communication quality information.

[0030] 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 the communication quality information acquired by the quality information acquisition unit 112 and whether the SQI level is less than 1.

[0031] 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 smaller than 1, the communication speed setting unit 114 reduces the communication speed of the communication path to one-tenth. 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.

[0032] 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 FIG. 4A, it is assumed that the communication quality (SQI) of the communication path set by the first communication unit 130 is 0 at time T1. In this case, the communication quality determination unit 113 determines that the quality of the communication path is not good because the SQI is smaller 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 FIG. 4A, the SQI, which indicates communication quality, is improved to 5 at time T2.

[0033] 4B shows an example in which the SQI, which indicates communication quality, remains at 0 at time T2 and the communication quality does not improve, as "Case 2." In this case, the communication path setting unit 111 sets the communication path to the second communication unit 140. In the example shown in FIG. 4B, an example is shown in which the SQI, which indicates communication quality, improves to 7 at time T3 for the communication path set by the second communication unit 140.

[0034] In the example shown in Fig. 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 Fig. 4C, an example in which the SQI, which indicates the communication quality, improves to 3 at time T4 is shown.

[0035] 4D, at time T4, the SQI, which is the communication quality, remains at 0, and an example in which the 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.

[0036] As described above, in this embodiment, an example has been shown in which the communication speed setting unit 114 reduces the communication speed of the communication path to one-tenth when the SQI, which indicates the communication quality of the communication path, is smaller than 1. This is an effective means of improving communication quality when, for example, the communication quality of the communication path is degraded due to noise or the like, and communication is possible without being affected by the noise by reducing the communication speed, as shown in Fig. 5. Here, noise that affects the communication path corresponds to, for example, noise in the car radio frequency band.

[0037] Furthermore, in this embodiment, when 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 response to 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 portion.

[0038] When communication is impossible in all communication paths in 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 values ​​are 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. This makes it possible to alert the user when the quality of the communication path does not improve.

[0039] Furthermore, the warning display control unit 115 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 enables low-speed communication, such as CAN. The low-speed communication unit 150 corresponds to the third communication unit. The low-speed communication unit 150 communicates at a speed that is 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.

[0040] (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 Fig. 6. The series of operations of the in-vehicle communication device 100 shown in the flowchart in Fig. 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 Fig. 6 also ends when the power is turned off or an interrupt occurs to end the processing. In addition, in the following explanation of the flowchart, the same content as that described in the above explanation of the in-vehicle communication system 10 and the in-vehicle communication device 100 will be omitted or simplified.

[0041] In step S601, communication path setting unit 111 sets first communication unit 130 as a communication path for communicating with ECU 400.

[0042] In step S602, the quality information acquiring unit 112 acquires communication quality information of the communication path. Specifically, the quality information acquiring unit 112 acquires SQI information detected by the detecting unit 160 as communication quality information.

[0043] 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 repeatedly executed.

[0044] 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 smaller than 1, the communication speed setting unit 114 reduces the communication speed of the communication path to one-tenth.

[0045] 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, as communication quality information, SQI information detected by the detection unit 160. In step S605, the SQI information after the communication rate has been reduced by the communication rate setting unit 114 is acquired as communication quality information.

[0046] In step S606, 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, similarly to step S603. Specifically, the communication quality determination unit 113 determines whether the SQI is less than 1 or not 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 repeatedly executed.

[0047] In step S607, control unit 110 determines whether second communication unit 140 is set as a communication path. If control unit 110 determines in step S607 that second communication unit 140 is set as a communication path (step S607: YES), the process proceeds to step S608. On the other hand, if control unit 110 determines in step S607 that second communication unit 140 is not set as a communication path (step S607: NO), the process proceeds to step S609.

[0048] 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 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.

[0049] In step S609, communication path setting unit 111 sets second communication unit 140 as a communication path for communicating with ECU 400. Thereafter, the process returns to step S602, and the process from step S602 is repeatedly executed.

[0050] 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 is set as the communication path.

[0051] 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 mounted on 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 or not based on a quality value of the communication quality information. 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. Furthermore, when the quality value of the communication quality information is lower than a predetermined value for the communication path whose communication speed has been reduced, 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.

[0052] 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 communicate without being affected by the noise by lowering the communication speed. Also, the in-vehicle communication device 100 can improve the communication quality in response to a malfunction (failure) of 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 fitting portion. In other words, the in-vehicle communication device 100 can improve the communication quality when the communication quality of the in-vehicle network is degraded.

[0053] As described above, the in-vehicle communication device 100 further includes the warning display control unit 115. When the quality values ​​of 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 are lower than a predetermined value, the warning display control unit 115 displays a warning on the display unit 300. This makes it possible to alert the user when the quality of the communication path does not improve.

[0054] Furthermore, the warning display control unit 115 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 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, so that the warning can be reliably displayed on the display unit 300.

[0055] Furthermore, the above-mentioned communication quality information uses SQI. This SQI is a value acquired in existing systems as information about the communication path of a vehicle network. That is, the in-vehicle communication device 100 does not need to provide a new device for acquiring the quality of the communication path, and in its implementation, it is possible to achieve a smaller device and lower power consumption.

[0056] (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.

[0057] In the above-described embodiment, an example has been described in which, when the SQI indicating the quality value of a communication path is lower than 1, the communication speed of the communication path is first reduced, and if the communication quality of the communication path is still not improved, the communication path is switched. For example, the in-vehicle communication device 100 may be configured to first switch the communication path, and if the communication quality is still not improved, to reduce the communication speed. The configuration of first switching the communication path can be applied to, for example, a location where a malfunction of a component on the communication path (fixed route failure) is likely to occur, thereby making it possible to more effectively improve communication quality.

[0058] In the above-described embodiment, 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, the detection unit 160 may acquire the SNR of a signal, calculate the SQI based on the SNR and reference information in the communication quality information DB 122 stored in advance, and the communication quality determination unit 113 may determine the quality of the communication path. For example, the reference information may be information comparing the SQI and SNR shown in FIG. 3, which is 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 range of SNR for this SQI, it is possible to realize an in-vehicle communication device 100 that can accommodate various communication qualities.

[0059] Furthermore, a computer program (communication program) that causes a computer to execute the processing (on-vehicle communication method) in the on-vehicle communication device 100 described above, 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 recording medium, and may be transmitted via a telecommunications line, a wireless or wired communication line, a network such as the Internet, or the like.

[0060] The features of the in-vehicle communication device 100 and the in-vehicle communication method will be described below.

[0061] An in-vehicle communication device 100 according to a 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 a first communication unit 130 or a 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 a quality value of the communication quality information. The in-vehicle communication device 100 also includes a communication speed setting unit 114 that reduces 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 a predetermined value for the communication path whose communication speed has been reduced.

[0062] According to 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. Also, the in-vehicle communication device 100 can improve the communication quality in response to a malfunction (failure) of 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 fitting portion. In other words, the in-vehicle communication device 100 can improve the communication quality when the communication quality of the in-vehicle network is degraded.

[0063] The in-vehicle communication device 100 according to the second aspect may further include a warning display control unit 115. In addition, the warning display control unit 115 may cause the display unit 300 to display a warning when the quality values ​​of 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 are lower than a predetermined value.

[0064] According to the above configuration, the in-vehicle communication device 100 can warn the user when the quality of the communication path does not improve.

[0065] The warning display control unit 115 of the in-vehicle communication device 100 relating 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 to which the first communication unit 130 and the second communication unit 140 are set and whose communication speed has been reduced.

[0066] According to 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, so that it is possible to reliably display a warning on the display unit 300.

[0067] The communication quality information of the in-vehicle communication device 100 according to the fourth embodiment may be a signal quality index / indicator (SQI).

[0068] According to this configuration, the in-vehicle communication device 100 uses the SQI applied in existing systems, so there is no 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.

[0069] An in-vehicle communication method according to a fifth aspect is an in-vehicle communication method executed by a computer. The in-vehicle communication method sets one of the first communication unit 130 and 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 or not based on a quality value of the communication quality information. The in-vehicle communication method also reduces the communication speed of the communication path when 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 and the second communication unit as the communication path when the quality value of the communication quality information is lower than the predetermined value for the communication path whose communication speed has been reduced.

[0070] According to 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, thereby enabling communication without being affected by the noise. Furthermore, the in-vehicle communication method can improve communication quality in response to a malfunction (failure) of 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 fitting portion. In other words, when the communication quality of the in-vehicle communication method or the in-vehicle network is degraded, it becomes possible to improve communication quality. [Explanation of symbols]

[0071] 10. In-vehicle communication systems 100 In-vehicle communication device 101, 201, 301 Connectors 110 control section 111 Communication path setting unit 112 Quality Information Acquisition Department 113 Communication quality judgment unit 114 Communication speed setting section 115 Warning display control unit 120 Storage section 121 Communication Route Information DB 130 First Communications Department 140 Second Communications Department 150 Low-speed communication section 160 Detection unit 200 Switches 300 Display 400 ECU

Claims

1. 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.

2. The in-vehicle communication device according to claim 1 , wherein the communication quality information is a signal quality index / indicator (SQI).

3. 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.

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