Vehicle-mounted communication system and transmission path evaluation method

Abstract

Provided are an in-vehicle communication system and a transmission path evaluation method. The in-vehicle communication system includes a plurality of communication transmission paths, a first electronic device, and a plurality of second electronic devices, the second electronic devices are directly connected to the first electronic device through the communication transmission paths or indirectly connected to the first electronic device via the communication transmission paths and other second electronic devices, the first electronic device has an evaluation unit that transmits a prescribed evaluation signal to one of the second electronic devices as a target device, receives a reply signal replied by the target device in response to the evaluation signal, and evaluates a transmission quality of the communication transmission path from the first electronic device to the target device, the second electronic devices have a first communicator that transmits the evaluation signal as the reply signal to the first electronic device in a direction opposite to a transmission direction of the evaluation signal received as the target device, and the evaluation unit stores an evaluation result of the transmission quality in correspondence with the second electronic device as the target device.

Description

Technical Field

[0001] This invention relates to an in-vehicle communication system and a transmission path evaluation method, which is capable of evaluating the transmission path between connected electronic devices in a vehicle. Background Technology

[0002] Patent Document 1 discloses a mobile terminal that evaluates the transmission quality of uplink and downlink lines by communicating with a fixed terminal via a communication network. In this mobile terminal, an evaluation result of the uplink transmission quality is obtained from the fixed terminal by sending a reference signal, and the downlink transmission quality is evaluated by comparing the reference signal received from the fixed terminal with a comparison reference signal. Furthermore, the mobile terminal stores the aforementioned evaluation results of the uplink and downlink transmission quality in association with information about its current location.

[0003] Patent Document 2 discloses a transmitting device for an in-vehicle communication system, wherein when the communication delay time of a first communication mode in a first communication unit exceeds a predetermined reference, communication is conducted via a second communication unit using a second communication mode that is limited by communication period and communication time. In this transmitting device, the communication delay time is defined, for example, as the time from the transmission instruction to send communication data to the first communication unit until the first communication unit receives a response from the receiving device.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-182607

[0007] Patent Document 2: Japanese Patent Application Publication No. 2015-46869 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] The communication network of an in-vehicle communication system, which consists of multiple electronic control devices, can be configured in various network topologies, including star, ring, and bus topologies. In such a communication network, if it is necessary to confirm the transmission quality and abnormal status of each transmission path connecting the electronic control devices, it would be inefficient to perform diagnostic communication as described in the prior art on each of the two electronic control devices included in the in-vehicle communication system individually.

[0010] The purpose of this invention is to efficiently evaluate the transmission quality of a communication transmission path in a vehicle communication system without performing separate diagnostic communication on each of the multiple communication transmission paths constituting the communication network.

[0011] Methods for solving problems

[0012] According to one aspect of the present invention, an in-vehicle communication system includes: a plurality of communication transmission paths mounted on a vehicle; a first electronic device; and a plurality of second electronic devices communicatively connected to the first electronic device via the communication transmission paths, characterized in that the second electronic devices are directly connected to the first electronic device communicatively via the communication transmission paths, or indirectly connected to the first electronic device communicatively via the communication transmission paths and other second electronic devices, the first electronic device having an evaluation unit that sends a predetermined evaluation signal to one of the second electronic devices as a target device, receives a response signal from the target device in response to receiving the evaluation signal, and evaluates the transmission quality of the communication transmission path from the first electronic device to the target device, the second electronic device having a communicator that sends the evaluation signal as the response signal to the first electronic device in a direction opposite to the transmission direction of the evaluation signal received by the second electronic device as the target device, and the evaluation unit of the first electronic device stores the evaluation result of the transmission quality in correspondence with the second electronic device as the target device.

[0013] According to another aspect of the present invention, the evaluation signal is composed of a sequence of a predetermined number of test signals, and the evaluation unit stores the number of test signals contained in the evaluation signal and the number of test signals contained in the response signal as the evaluation result of the transmission quality.

[0014] According to another aspect of the present invention, the communication transmission path and the first electronic device and a plurality of second electronic devices interconnected through the communication transmission path constitute a communication network. The evaluation unit of the first electronic device evaluates the transmission quality by sequentially treating each of the second electronic devices as the target device along the communication path from the first electronic device to the second electronic device at the end of the communication network, in the order from the second electronic device at the end to the second electronic device closest to the first electronic device.

[0015] According to another aspect of the invention, the communicator of the second electronic device relays the evaluation signal sent to another second electronic device as the object device to another second electronic device, and relays the reply signal from another second electronic device to the first electronic device.

[0016] According to another aspect of the present invention, the first electronic device and a plurality of second electronic devices are arranged in a tree structure with the first electronic device as the root, the second electronic devices as nodes or leaves, and the communication transmission path as branches. The evaluation unit of the first electronic device starts from the second electronic device that is the leaf and sequentially selects the second electronic devices that are closer to the first electronic device as nodes along the communication transmission path that is the branch, and evaluates the transmission quality accordingly.

[0017] According to another aspect of the present invention, the evaluation section of the first electronic device evaluates the transmission quality when the vehicle's drive system is in an on state and when it is in a off state, and stores the transmission quality evaluation in the on state and the transmission quality evaluation in the off state, respectively.

[0018] Another aspect of the present invention is a transmission path evaluation method, which is a transmission path evaluation method in a vehicle-mounted communication system. The vehicle-mounted communication system includes: multiple communication transmission paths mounted in a vehicle; a first electronic device; and multiple second electronic devices connected to the first electronic device communicatively via the communication transmission paths. The second electronic devices are characterized in that they are directly connected to the first electronic device communicatively via the communication transmission paths, or indirectly connected to the first electronic device communicatively via the communication transmission paths and other second electronic devices. The transmission path evaluation method includes the following steps: an evaluation unit of the first electronic device sends a predetermined evaluation signal to one of the second electronic devices as a target device; a communicator of the second electronic device as the target device receives the evaluation signal from the first electronic device and replies with the evaluation signal as a reply signal to the first electronic device in a direction opposite to the transmission direction of the received evaluation signal; the evaluation unit of the first electronic device receives the reply signal from the second electronic device as the target device and evaluates the transmission quality of the communication transmission path from the first electronic device to the target device; and the evaluation unit of the first electronic device stores the evaluation result of the transmission quality in correspondence with the second electronic device as the target device.

[0019] According to another aspect of the present invention, the evaluation signal is composed of a sequence of a predetermined number of test signals, and in the storage step, the evaluation unit stores the number of test signals contained in the evaluation signal and the number of test signals contained in the response signal as the evaluation result of the transmission quality.

[0020] Invention Effects

[0021] According to the present invention, in a vehicle communication system, the transmission quality of multiple communication transmission paths constituting a communication network can be efficiently evaluated without the need to perform separate diagnostics on each communication transmission path. Attached Figure Description

[0022] Figure 1 This is a diagram illustrating the structure of an in-vehicle communication system according to one embodiment of the present invention.

[0023] Figure 2 This is a diagram showing the structure of the first electronic device.

[0024] Figure 3 This is a diagram showing the structure of the second electronic device.

[0025] Figure 4 This is a flowchart illustrating the steps involved in the processing of evaluating transmission quality in a vehicle communication system.

[0026] Label Explanation

[0027] 1…vehicle, 2…vehicle communication system, 3…first electronic device, 4, 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h, 4i, 4j, 4k…second electronic device, 5, 5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j, 5k…communication transmission path, 6…first processor, 7…first memory, 8…first communicator, 9…transmitter, 10…receiver, 11…evaluation unit, 12…evaluation result, 13…first evaluation program, 14…second processor, 15…second memory, 16…second communicator, 17…turnaround control unit, 18…relay control unit, 19…second evaluation program, 20…first receiver, 21…first transmitter, 22…second receiver, 23…second transmitter. Detailed Implementation

[0028] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0029] Figure 1 This diagram illustrates the structure of an in-vehicle communication system 2 mounted on a vehicle 1 according to one embodiment of the present invention. The in-vehicle communication system 2 includes a first electronic device 3 and multiple second electronic devices 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h, 4i, 4j, and 4k, which serve as electronic control devices for controlling the operation of the vehicle 1. Hereinafter, the second electronic devices 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h, 4i, 4j, and 4k will be collectively referred to as second electronic devices 4.

[0030] The vehicle-mounted communication system 2 also includes multiple communication transmission paths 5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j, and 5k. Hereinafter, communication transmission paths 5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j, and 5k will be collectively referred to as communication transmission path 5.

[0031] The communication transmission path 5, together with the first electronic device 3 and multiple second electronic devices 4 interconnected through each communication transmission path 5, constitute a communication network. In this embodiment, as... Figure 1 As shown, the communication network has a tree structure with the first electronic device 3 as the root, the second electronic devices 4 as nodes or leaves, and the communication transmission path 5 as branches. Specifically, the second electronic devices 4a, 4b, 4c, 4d, 4e, 4f, and 4g, which are located between two second electronic devices 4 via the communication transmission path 5, respectively constitute the nodes of the tree structure of the aforementioned communication network. In addition, the second electronic devices 4h, 4i, 4j, and 4k, which are connected to only one second electronic device 4, are the leaves of the aforementioned tree structure and are located at the ends of the aforementioned communication network.

[0032] Each second electronic device 4 is directly connected to the first electronic device 3 in a communicable manner via a communication transmission path 5, or indirectly connected to the first electronic device 3 in a communicable manner via the communication transmission path 5 and other second electronic devices 4. Specifically, in this embodiment, second electronic devices 4a and 4b are directly connected to the first electronic device 3 in a communicable manner via communication transmission paths 5a and 5b, respectively. Furthermore, each of the second electronic devices 4c to 4k can be indirectly connected to the first electronic device 3 in a communicable manner via the communication transmission path 5 and other second electronic devices 4.

[0033] Figure 2 This diagram illustrates the structure of the first electronic device 3. The first electronic device 3 includes a first processor 6, a first memory 7, and a first communicator 8. The first memory 7 is, for example, composed of volatile and / or non-volatile semiconductor memory. The first communicator 8 is a transceiver used by the first electronic device 3 to communicate with the second electronic device 4 via a communication transmission path 5.

[0034] The first processor 6 is, for example, a computer equipped with a CPU (Central Processing Unit). The first processor 6 may also have a structure including a ROM (Read Only Memory) with programs written to it, RAM (Random Access Memory) for temporary data storage, etc. Furthermore, the first processor 6 includes a transmitting unit 9, a receiving unit 10, and an evaluation unit 11 as functional elements or units.

[0035] These functional elements possessed by the first processor 6 are implemented, for example, by the execution of a first evaluation program 13 stored in the first memory 7 by the first processor 6, which is a computer. The first evaluation program 13 can be pre-stored in any computer-readable storage medium. Alternatively, all or part of the aforementioned functional elements possessed by the first processor 6 can be constituted by hardware comprising one or more electronic circuit components.

[0036] According to the instructions from the evaluation unit 11, the transmitting unit 9 uses the first communicator 8 to designate any one of the second electronic devices 4 as the transmission destination to transmit an evaluation signal. For example, the transmitting unit 9 transmits the evaluation signal after sending an evaluation transmission notification to the second electronic device 4 designated as the transmission destination, indicating that the second electronic device 4 is the transmission destination of the evaluation signal.

[0037] The receiving unit 10 receives a reply signal from the second electronic device 4, which is designated as the aforementioned transmission destination, via the first communicator 8, and sends the reply signal to the evaluation unit 11.

[0038] The evaluation unit 11 evaluates the transmission quality of communication signals in each communication transmission path 5. Specifically, the evaluation unit 11 determines one of the second electronic devices 4 as the target device. The evaluation unit 11 sends a specified evaluation signal by designating the target device as the receiving destination via the transmitting unit 9. Then, the evaluation unit 11 receives a response signal from the second electronic device 4, which is the target device, in response to receiving the evaluation signal via the receiving unit 10.

[0039] Then, the evaluation unit 11 evaluates the transmission quality of the communication transmission path 5 from the first electronic device 3 to the second electronic device 4, which is the object device, by comparing the transmitted evaluation signal and the received response signal. The evaluation unit 11 stores the evaluation result 12, which represents the result of the evaluation, in the first memory 7, corresponding to the second electronic device 4, which is the object device.

[0040] The aforementioned evaluation signal is, for example, composed of a sequence of a predetermined number of test signals. The evaluation unit 11 stores the number of test signals m contained in the evaluation signal and the number of test signals n contained in the response signal as an evaluation result 12 of the transmission quality in the first memory 7, corresponding to the second electronic device 4, which is the target device. Here, the test signal may, for example, be a signal representing a predetermined code (e.g., a character code).

[0041] In this embodiment, in particular, the evaluation unit 11 evaluates the transmission quality of each second electronic device as a target device along the communication path from the first electronic device 3 to the second electronic device 4 at the end of the communication network.

[0042] Specifically, in this embodiment, the evaluation unit 11 starts with the second electronic device 4, which is a leaf in the above-mentioned communication network with a tree structure, and sequentially determines the second electronic device 4, which is a node closer to the first electronic device 3, as the target device along the communication transmission path 5, which is a branch, and performs the above-mentioned evaluation of transmission quality.

[0043] For example, in Figure 1 In the process, the evaluation unit 11, following the communication path that sequentially passes through the first electronic device 3, communication transmission path 5a, second electronic device 4a, communication transmission path 5e, and second electronic device 4e to reach the terminal second electronic device 4j, first evaluates the transmission quality of the terminal second electronic device 4j as the target device. At this time, the propagation path of the evaluation signal is... Figure 1 The diagram uses dashed lines to represent these components. Next, the evaluation unit 11 evaluates the transmission quality of the second electronic devices 4e and 4a, which are closer to the first electronic device 3, sequentially along the aforementioned communication path. The propagation path of the evaluation signals during these evaluations is... Figure 1 The dashed lines are represented by single-dot and double-dot lines, respectively.

[0044] Therefore, by comparing the results of the transmission quality evaluations performed sequentially as described above, it is easy to determine whether the transmission quality of each of the communication transmission paths 5 contained in the communication path is good.

[0045] Furthermore, the evaluation unit 11 performs the aforementioned transmission quality evaluation when the drive unit (not shown) of the vehicle 1 is in the on state and in the off state, respectively, and stores the evaluation results 12, representing the transmission quality evaluation in the on state and the off state, in the first memory 7. Here, the drive unit refers to, for example, an internal combustion engine or motor that drives the wheels of the vehicle 1.

[0046] Therefore, it is possible to easily and efficiently grasp the impact of the drive unit, which may be the main noise source in vehicle 1, on the transmission quality of communication transmission path 5.

[0047] Figure 3This diagram illustrates the structure of the second electronic device 4. The second electronic device 4 includes a second processor 14, a second memory 15, and a second communicator 16. The second memory 15 is, for example, composed of volatile and / or non-volatile semiconductor memory. The second communicator 16 is a transceiver used by the second electronic device 4 to communicate with the first electronic device 3 and other second electronic devices 4 via a communication transmission path 5. In this embodiment, the second communicator 16 includes a first receiver 20, a first transmitter 21, a second receiver 22, and a second transmitter 23.

[0048] The first receiver 20 and the first transmitter 21 are a receiver and a transmitter for communicating via a communication transmission path 5 connected from the direction of the first electronic device 3. Here, "communication transmission path 5 connected from the direction of the first electronic device 3" refers, for example, to the second electronic device 4d, to the communication transmission path 5d connected from the direction of the first electronic device 3, and to the second electronic device 4e, to the communication transmission path 5e connected from the direction of the first electronic device 3.

[0049] Furthermore, the second receiver 22 and the second transmitter 23 are receivers and transmitters used for communication via a communication transmission path 5 connected from a direction opposite to the direction of the first electronic device 3. Here, "communication transmission path 5 connected from a direction opposite to the direction of the first electronic device 3" refers, for example, to communication transmission path 5i connected from a direction opposite to the direction of the first electronic device 3 for the second electronic device 4d, and to communication transmission paths 5j and 5k connected from a direction opposite to the direction of the first electronic device 3 for the second electronic device 4e. Moreover, in the case where there are multiple communication transmission paths 5 connected from a direction opposite to the direction of the first electronic device 3, as in the case of the second electronic device 4e, the second receiver 22 and the second transmitter 23 can each, according to the prior art, include at least the same number of receivers and transmitters as the number of communication transmission paths 5 connected to them.

[0050] The second processor 14 is, for example, a computer equipped with a CPU. The first processor 6 may also have a structure with a ROM on which programs are written, RAM for temporary data storage, etc. Furthermore, the second processor 14 includes a turnaround control unit 17 and a relay control unit 18 as functional elements or functional units.

[0051] These functional elements possessed by the second processor 14 are implemented, for example, by the second processor 14, which is a computer, executing a second evaluation program 19 stored in the second memory 15. The second evaluation program 19 can be pre-stored in any computer-readable storage medium. Alternatively, all or part of the aforementioned functional elements possessed by the second processor 14 can be constructed by hardware comprising one or more electronic circuit components.

[0052] When the turnaround control unit 17 receives an evaluation transmission notification for the device from the first electronic device 3 via the first receiver 20 of the second communicator 16, it sets the second communicator 16 to a turnaround operation mode. A turnaround operation mode refers to an operation mode in which, after receiving the evaluation transmission notification, the evaluation signal is transmitted to the first electronic device 3 in a direction opposite to the transmission direction of the received evaluation signal. The second communicator 16 set to the turnaround operation mode is equivalent to the "communicator that transmits the evaluation signal as a reply signal to the first electronic device in a direction opposite to the transmission direction of the evaluation signal received as the target device" in this disclosure.

[0053] In this embodiment, for example, when the turnaround control unit 17 receives an evaluation transmission notification, it instructs the second communicator 16 to connect the output of the first receiver 20 to the input of the first transmitter 21, thereby setting the second communicator 16 to turnaround operation mode. Furthermore, when the turnaround transmission based on the evaluation signal from the first receiver 20 and the first transmitter 21 ends, the turnaround control unit 17 instructs the second communicator 16 to deactivate the turnaround operation mode, thereby disconnecting the output of the first receiver 20 from the input of the first transmitter 21.

[0054] When the relay control unit 18 receives an evaluation transmission notification from the first electronic device 3 indicating that another second electronic device 4 is the transmission destination, it sets the second communicator 16 to relay operation mode. Relay operation mode refers to the following operation mode: after receiving the evaluation transmission notification indicating that another second electronic device 4 is the transmission destination, the evaluation signal sent to the other second electronic device 4 (i.e., the target device) is relayed to the other second electronic device 4, and the reply signal from the other second electronic device 4 is relayed to the first electronic device 3.

[0055] In this embodiment, for example, when the relay control unit 18 receives an evaluation transmission notification indicating that another second electronic device 4 is the transmission destination, it instructs the second communicator 16 to connect the output of the first receiver 20 to the input of the second transmitter 23, and to connect the output of the second receiver 22 to the input of the first transmitter 21, thus setting the second communicator 16 to relay operation mode. Furthermore, for example, after a predetermined time has elapsed since the second communicator 16 was set to relay operation mode, the relay control unit 18 instructs the second communicator 16 to de-enable relay operation mode, thereby disconnecting the output of the first receiver 20 from the input of the second transmitter 23, and the output of the second receiver 22 from the input of the first transmitter 21.

[0056] The vehicle communication system 2 with the above structure can evaluate the transmission quality of all communication transmission paths from the first electronic device 3 to the second electronic device 4, which is the target device, and thus can efficiently evaluate the transmission quality of the communication transmission paths.

[0057] Furthermore, in the vehicle-mounted communication system 2, the transmission quality is evaluated by comparing the number of test signals contained in the evaluation signal with the number of test signals contained in the response signal. Therefore, the transmission quality of the communication transmission path can be evaluated through simple processing.

[0058] Furthermore, in the vehicle communication system 2, since the target devices are determined sequentially from the more distant second electronic device 4 along the communication path, and the transmission quality is evaluated sequentially, by comparing the results of these evaluations, it is easy to determine whether the transmission quality in each communication transmission path 5 included in the communication path is good.

[0059] Next, the steps for evaluating the transmission quality in the vehicle communication system 2 will be explained. Figure 4 This is a flowchart illustrating the steps involved in the processing of evaluating the transmission quality in the vehicle-mounted communication system 2. Figure 4 The processing can begin, for example, when predetermined conditions such as whether the drive unit of vehicle 1 is on or off are met. Figure 4 In this process, the first electronic device 3 and all of the second electronic devices 4 are activated and begin to work.

[0060] When processing begins, the evaluation unit 11 selects a communication path from the first electronic device 3 to the second electronic device 4 located at the end of the communication network that has not yet been evaluated for transmission quality (hereinafter referred to as an unevaluated communication path) (S100). Next, the evaluation unit 11 identifies the second electronic device 4 furthest from the first electronic device 3 among the second electronic devices 4 included in the selected communication path that have not yet been determined as target devices (hereinafter referred to as unevaluated second electronic devices 4) as the target device (S102). Then, the evaluation unit 11 sends an evaluation signal to the second electronic device 4 that has been determined as the target device (S104).

[0061] The second communicator 16 of the second electronic device 4, which is the target device, receives the evaluation signal from the first electronic device 3 and replies the evaluation signal as a reply signal to the first electronic device 3 in the opposite direction to the transmission direction (S106). Next, the evaluation unit 11 of the first electronic device 3 receives the reply signal from the second electronic device 4, which is the target device, and compares the transmitted evaluation signal with the received reply signal to evaluate the transmission quality of the communication transmission path 5 from the first electronic device 3 to the second electronic device 4, which is the target device (S108).

[0062] Then, the evaluation unit 11 stores the transmission quality evaluation result 12 in the first memory 7, corresponding to the second electronic device 4, which is the target device, (S110). As described above, the evaluation signal consists of a sequence of a predetermined number of test signals. In step S110, the evaluation unit 11 stores the number of test signals contained in the evaluation signal and the number of test signals contained in the response signal as the transmission quality evaluation result 12 in the first memory 7, corresponding to the second electronic device 4, which is the target device.

[0063] Next, the evaluation unit 11 determines whether there is an unevaluated second electronic device 4 in the selected communication path (S112). Then, if there is an unevaluated second electronic device 4 in the selected communication path (S112: Yes), the evaluation unit 11 returns to step S102 and repeats the process.

[0064] On the other hand, in step S112, if there is no unevaluated second electronic device 4 among the selected communication paths (S112: No), the evaluation unit 11 determines whether there is a communication path whose transmission quality has not yet been evaluated (hereinafter referred to as an unevaluated communication path) (S114). Then, if there is an unevaluated communication path (S114: Yes), the evaluation unit 11 returns to step S100 and repeats the process. On the other hand, if there is no unevaluated communication path (S114: No), the evaluation unit 11 ends the process.

[0065] Furthermore, the present invention is not limited to the structure of the embodiments described above, and can be implemented in various ways without departing from its spirit.

[0066] The above implementation supports the following structure.

[0067] (Structure 1) A vehicle-mounted communication system includes: multiple communication transmission paths mounted on a vehicle; a first electronic device; and multiple second electronic devices connected to the first electronic device in a communicative manner via the communication transmission paths, characterized in that the second electronic devices are directly connected to the first electronic device in a communicative manner via the communication transmission paths, or indirectly connected to the first electronic device via the communication transmission paths and other second electronic devices in a communicative manner; the first electronic device has an evaluation unit that sends a predetermined evaluation signal to one of the second electronic devices as a target device, receives a response signal from the target device in response to receiving the evaluation signal, and evaluates the transmission quality of the communication transmission path from the first electronic device to the target device; the second electronic device has a communicator that sends the evaluation signal as the response signal to the first electronic device in a direction opposite to the transmission direction of the evaluation signal received by the second electronic device as the target device; and the evaluation unit of the first electronic device stores the evaluation result of the transmission quality in correspondence with the second electronic device as the target device.

[0068] According to the vehicle communication system of Structure 1, the transmission quality of the entire communication transmission path from the first electronic device to the second electronic device which is the target device can be evaluated at the same time, thus enabling efficient evaluation of the transmission quality of the communication transmission path.

[0069] (Structure 2) The vehicle communication system of Structure 1, wherein the evaluation signal is composed of a sequence of a predetermined number of test signals, and the evaluation unit stores the number of test signals contained in the evaluation signal and the number of test signals contained in the response signal as the evaluation result of the transmission quality.

[0070] According to the vehicle communication system of Structure 2, the transmission quality of the communication transmission path can be evaluated through simple processing.

[0071] (Structure 3) A vehicle communication system of Structure 1 or 2, wherein the communication transmission path and a first electronic device and a plurality of second electronic devices interconnected by the communication transmission path constitute a communication network, and the evaluation unit of the first electronic device evaluates the transmission quality by sequentially treating each of the second electronic devices as the target device along the communication path from the first electronic device to the second electronic device at the end of the communication network, in the order from the second electronic device at the end to the second electronic device closest to the first electronic device.

[0072] According to the vehicle communication system of structure 3, by comparing the evaluation results of the transmission quality evaluated in sequence, it is easy to determine whether the transmission quality of each communication transmission path contained in the communication path is good or bad.

[0073] (Structure 4) An in-vehicle communication system of any one of Structures 1 to 3, wherein the communicator of the second electronic device relays the evaluation signal sent to another second electronic device as the target device to the other second electronic device, and relays the reply signal from the other second electronic device to the first electronic device.

[0074] According to the vehicle communication system of structure 4, even in the case of a communication network in which the second electronic device is connected in multiple levels, the transmission quality of the communication transmission path can be evaluated efficiently.

[0075] (Structure 5) A vehicle communication system of Structure 1 or 2, wherein the first electronic device and a plurality of second electronic devices are arranged in a tree structure with the first electronic device as the root, the second electronic devices as nodes or leaves, and the communication transmission path as branches. The evaluation unit of the first electronic device starts from the second electronic device that is the leaf and sequentially takes the second electronic devices that are closer to the first electronic device as nodes along the communication transmission path that is the branch as the target device, and evaluates the transmission quality.

[0076] According to the vehicle communication system of structure 5, even in the case of a tree-structured communication network in which the second electronic device is connected in multiple levels, the transmission quality of the communication transmission path can be evaluated efficiently.

[0077] (Structure 6) A vehicle communication system of any one of Structures 1 to 4, wherein the evaluation part of the first electronic device evaluates the transmission quality when the vehicle's drive device is in an on state and in a off state, and stores the transmission quality evaluation in the on state and the transmission quality evaluation in the off state, respectively.

[0078] According to the vehicle communication system of Structure 6, it is possible to easily and efficiently grasp the impact of drive devices, which may become the main noise source in the vehicle, on the transmission quality of the communication transmission path.

[0079] (Structure 7) A transmission path evaluation method, which is a transmission path evaluation method in a vehicle-mounted communication system, the vehicle-mounted communication system comprising: multiple communication transmission paths mounted in a vehicle; a first electronic device; and multiple second electronic devices connected to the first electronic device in a communicative manner via the communication transmission paths, characterized in that the second electronic devices are directly connected to the first electronic device in a communicative manner via the communication transmission paths, or indirectly connected to the first electronic device in a communicative manner via the communication transmission paths and other second electronic devices, the transmission path evaluation method comprising the following steps: the evaluation unit of the first electronic device sends a predetermined evaluation signal to one of the second electronic devices as a target device; the communicator of the second electronic device as the target device receives the evaluation signal from the first electronic device and replies to the first electronic device as a reply signal in a direction opposite to the transmission direction of the received evaluation signal; the evaluation unit of the first electronic device receives the reply signal from the second electronic device as the target device and evaluates the transmission quality of the communication transmission path from the first electronic device to the target device; and the evaluation unit of the first electronic device stores the evaluation result of the transmission quality in correspondence with the second electronic device as the target device.

[0080] According to the transmission path evaluation method of structure 7, the transmission quality of all communication transmission paths from the first electronic device to the second electronic device which is the target device can be evaluated at the same time, thus enabling efficient evaluation of the transmission quality of communication transmission paths.

[0081] (Structure 8) The transmission path evaluation method of Structure 7, wherein the evaluation signal is composed of a sequence of a predetermined number of test signals, and in the storage step, the evaluation unit stores the number of test signals contained in the evaluation signal and the number of test signals contained in the response signal as the evaluation result of the transmission quality.

[0082] According to the transmission path evaluation method in Structure 8, the transmission quality of the communication transmission path can be evaluated through simple processing.

Claims

1. A vehicle-mounted communication system, comprising: Multiple communication transmission paths are mounted on the vehicle; First electronic device; And a plurality of second electronic devices, which are communicatively connected to the first electronic device via the communication transmission path. The second electronic device is directly connected to the first electronic device in a communicative manner via the communication transmission path, or indirectly connected to the first electronic device via the communication transmission path and other second electronic devices in a communicative manner. The first electronic device has an evaluation unit that sends an evaluation signal consisting of a sequence of a predetermined number of test signals to one of the second electronic devices as a target device, receives a response signal from the target device in response to receiving the evaluation signal, and evaluates the transmission quality of the communication transmission path from the first electronic device to the target device. The second electronic device has a communicator that transmits the evaluation signal as a response signal to the first electronic device in a direction opposite to the transmission direction of the evaluation signal received by the second electronic device as the object device. The evaluation unit of the first electronic device stores the number m of test signals contained in the evaluation signal and the number n of test signals contained in the response signal as the evaluation result of the transmission quality, corresponding to the second electronic device as the target device, in its memory. The evaluation section of the first electronic device evaluates the transmission quality when the vehicle's drive system is in an on state and when it is in a off state, and stores the transmission quality evaluation when the system is on and when it is off, respectively.

2. The vehicle-mounted communication system according to claim 1, wherein, The communication transmission path, together with the first electronic device and multiple second electronic devices interconnected through the communication transmission path, constitutes a communication network. The evaluation unit of the first electronic device evaluates the transmission quality by sequentially treating each of the second electronic devices as the target device, starting from the second electronic device at the end of the communication network and continuing to the second electronic device closest to the first electronic device.

3. The vehicle-mounted communication system according to claim 1, wherein, The communicator of the second electronic device relays the evaluation signal sent to other second electronic devices that are the target devices, and relays the reply signal from other second electronic devices to the first electronic device.

4. The vehicle-mounted communication system according to claim 1, wherein, The first electronic device and the plurality of second electronic devices are arranged in a tree structure with the first electronic device as the root, the second electronic devices as nodes or leaves, and the communication transmission path as branches. The evaluation unit of the first electronic device evaluates the transmission quality starting from the second electronic device, which is the leaf, and sequentially takes the second electronic devices, which are closer to the first electronic device and are the nodes, as the target devices along the communication transmission path, which is the branch.

5. A transmission path evaluation method, which is a transmission path evaluation method in a vehicle-mounted communication system, the vehicle-mounted communication system comprising: Multiple communication transmission paths are mounted on the vehicle; First electronic device; And a plurality of second electronic devices, which are communicatively connected to the first electronic device via the communication transmission path, characterized in that, The second electronic device is directly connected to the first electronic device in a communicative manner via the communication transmission path, or indirectly connected to the first electronic device via the communication transmission path and other second electronic devices in a communicative manner. The transmission path evaluation method includes the following steps: The evaluation unit of the first electronic device sends an evaluation signal consisting of a sequence of a predetermined number of test signals to one of the second electronic devices as the target device; The communicator of the second electronic device, which is the object device, receives the evaluation signal from the first electronic device and replies the evaluation signal as a reply signal to the first electronic device in a direction opposite to the transmission direction of the received evaluation signal. The evaluation unit of the first electronic device receives a response signal from the second electronic device, which is the target device, and evaluates the transmission quality of the communication transmission path from the first electronic device to the target device; and The evaluation unit of the first electronic device stores the number m of test signals contained in the evaluation signal and the number n of test signals contained in the response signal as the evaluation result of the transmission quality, corresponding to the second electronic device as the target device, in its memory. The evaluation section of the first electronic device evaluates the transmission quality when the vehicle's drive system is in an on state and when it is in a off state, and stores the transmission quality evaluation when the system is on and when it is off, respectively.

Images