Relay device

Abstract

To provide a technology for easily imparting a transmission time to a frame received by a relay device.SOLUTION: The determination unit 55 is configured to determine whether or not a transmission time, which is a time at which the first communication device transmits a frame, is assigned to the frame. The addition unit 56 is configured to add a pseudo transmission time, which is a time based on a reception time that is a time at which the reception unit 54 has received the frame, to the frame received by the reception unit 54 as the transmission time when the determination unit 55 determines that the transmission time is not added to the frame.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a relay device. [Background technology]

[0002] Patent Document 1 below proposes a technique for estimating the time at which a device generates data. Specifically, a time-stamping device estimates a delay time in advance based on the time it takes for a time-stamping device to send an ICMP (Internet Control Message Protocol) echo request packet to a device and receive a response message. When the time-stamping device receives data from a device, it calculates the time at which the device generated the data, taking into account the estimated delay time. The time-stamping device then transfers the data including the calculated time. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-213033 Summary of the Invention [Problem to be solved by the invention]

[0004] However, after careful consideration by the inventors, another configuration was discovered that allows the device receiving the data to more easily assign to the frame the time the data was generated, i.e., the time the frame was transmitted.

[0005] One aspect of the present disclosure provides a technique that enables a relay device to easily assign a transmission time to a frame received by the relay device. [Means for solving the problem]

[0006] One aspect of the present disclosure is a relay device (5) mounted on a vehicle and used in a communication system (100) configured to enable communication between first communication devices (1-3) and a second communication device (4). The relay device includes a receiver (54), a determiner (55), an assigner (56), and a transmitter (57). The receiver is configured to receive a frame transmitted from the first communication device. The determiner is configured to determine whether a transmission time, which is the time at which the first communication device transmitted the frame, is assigned to the frame. If the determiner determines that the frame does not have a transmission time assigned to it, the assigner is configured to assign a pseudo transmission time, which is based on the reception time, which is the time at which the receiver received the frame, to the frame received by the receiver as the transmission time. The transmitter is configured to transmit the frame to which the pseudo transmission time has been assigned by the assigner to the second communication device.

[0007] With this configuration, the relay device can easily assign a transmission time to a frame transmitted by the first communication device that does not have a function for assigning a transmission time to a frame. In other words, the relay device can easily assign a transmission time to a frame received by the relay device. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of a schematic configuration of a communication system. [Figure 2] FIG. 1 is a block diagram showing a configuration of a communication system. [Figure 3] 10 is the first half of a flowchart showing a transmission time assignment process. [Figure 4] 10 is the second half of a flowchart showing a transmission time setting process. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. [1. Embodiment] [1-1.Configuration] The communication system 100 of the embodiment shown in FIGS. 1 and 2 constitutes an Ethernet (registered trademark) network system mounted on a vehicle such as a passenger car. Note that the network is not limited to Ethernet and may be any network using any communication protocol. The communication protocol may include LIN, CAN (registered trademark), FlexRay (registered trademark), MOST (registered trademark), and CXPI (registered trademark). LIN is an abbreviation for "Local Interconnect Network." CAN is an abbreviation for "Controller Area Network." MOST is an abbreviation for "Media Oriented Systems Transport." CXPI is an abbreviation for "Clock Extension Peripheral Interface."

[0010] The communication system 100 includes a plurality of electronic control devices, ECU1, ECU2, ECU3, and ECU4 (hereinafter referred to as ECU1-4), and a relay device 5. The ECU1-4 are each connected to the relay device 5 via a communication line. ECU is an abbreviation for "Electronic Control Unit."

[0011] Sensors, actuators, etc. (not shown) are connected to the ECUs 1 to 4. The ECUs 1 to 4, for example, realize a function of transmitting data (e.g., frames) obtained from the sensors to the other ECUs 1 to 4 via the relay device 5. Furthermore, for example, the ECUs 1 to 4 realize a function of operating actuators based on data received from the other ECUs 1 to 4 via the relay device 5. Furthermore, the ECUs 1 to 4 have a function of transmitting and receiving data to and from the relay device 5 to which they are connected.

[0012] That is, in the communication system 100, the ECUs 1 to 4 are connected to each other so as to be able to communicate with each other via the relay device 5. In other words, the ECUs 1 to 4 are configured so as to be able to transmit and receive data to and from each other via the relay device 5. Hereinafter, as an example, this embodiment will be described using a situation in which the ECUs 1 to 3 function as transmitting devices that transmit data, and the ECU 4 functions as a receiving device that receives data. As an example, as shown in FIG. 1, the ECU 1 transmits data A, the ECU 2 transmits data B, and the ECU 3 transmits data C. Note that the ECUs 1 to 3 may also be referred to as transmitting devices, and the ECU 4 as a receiving device. The ECUs 1 to 4 and the relay device 5 may also be referred to as nodes.

[0013] [1-1-1.Transmitting device] 2, the ECU 1 includes a CPU 11 and a memory 12. The memory 12 stores programs that enable the CPU 11 to execute predetermined functions.

[0014] The ECU 1 realizes the functions of the following units by the CPU 11 executing the programs in the memory 12. That is, the ECU 1 has the functions of a time synchronization unit 13, a transmission time setting unit 14, and a transmission / reception unit 15.

[0015] The time synchronization unit 13 is configured to synchronize time with other nodes that also have time synchronization units. For example, IEEE802.1AS is used for time synchronization. Specifically, the local time used in one node is synchronized with the global time used in the other nodes. IEEE is an abbreviation for "Institute of Electrical and Electronics Engineers."

[0016] The transmission time setting unit 14 is configured to set the transmission time ST of the frame to the header of the frame. More precisely, the transmission time ST of the frame can be said to be the time immediately before the transmitting / receiving unit 15 transmits the frame, or the time when the frame is generated. The frame header may use a format defined in IEEE1722. The transmitting / receiving unit 15 is configured to transmit and receive frames. In this embodiment, the transmitting / receiving unit 15 transmits frames to the ECU 4 via the relay device 5.

[0017] The ECU 2 includes a CPU 21 and a memory 22. The memory 22 stores programs that enable the CPU 21 to execute predetermined functions.

[0018] The ECU 2 realizes the functions of the following units by the CPU 21 executing the programs in the memory 22. That is, the ECU 2 has the functions of a time synchronization unit 23 and a transmission / reception unit 24. The ECU 2 differs from the ECU 1 in that it does not have a transmission time setting unit.

[0019] The time synchronization unit 23 is configured to synchronize the time with other nodes that also have time synchronization units. The transmitting / receiving unit 24 is configured to transmit and receive frames. In this embodiment, the transmitting / receiving unit 24 transmits frames to the ECU 4 via the relay device 5. However, since the ECU 2 does not include a transmission time setting unit, the header of the frame transmitted from the ECU 2 does not include the transmission time ST of the frame.

[0020] The ECU 3 includes a CPU 31 and a memory 32. The memory 32 stores programs that enable the CPU 31 to execute predetermined functions. The ECU 3 realizes the functions of the following units by the CPU 31 executing the programs in the memory 32. That is, the ECU 3 has the function of a transmitter / receiver 33. Note that the ECU 3 differs from the ECU 1 in that it does not have a time synchronization unit or a transmission time setting unit.

[0021] The transmitter / receiver 33 is configured to transmit and receive frames. In this embodiment, the transmitter / receiver 33 transmits frames to the ECU 4 via the relay device 5. However, since the ECU 3 does not have a time synchronization unit, it cannot synchronize time with other nodes that have time synchronization units. Furthermore, since the ECU 3 does not have a transmission time setting unit, the header of a frame transmitted from the ECU 3 does not have the transmission time ST of the frame set.

[0022] [1-1-2. Receiving device] The ECU 4 includes a CPU 41 and a memory 42. The memory 42 stores programs that enable the CPU 41 to execute predetermined functions.

[0023] The ECU 4 realizes the functions of the following units by the CPU 41 executing the programs in the memory 42. That is, the ECU 4 has the functions of a time synchronization unit 43 and a transmission / reception unit 44.

[0024] The time synchronization unit 43 is configured to synchronize the time with other nodes that also have time synchronization units. The transmitting / receiving unit 44 is configured to transmit and receive frames. In this embodiment, the transmitting / receiving unit 44 receives frames from the ECUs 1 to 3 via the relay device 5.

[0025] [1-1-3.Relay device] The relay device 5 has a relay function of transferring a frame received from an ECU connected to the relay device 5 to another ECU connected to the relay device 5. That is, in this embodiment, the relay device 5 relays communications between the ECUs 1 to 4. The relay device 5 may also have a function as a gateway device. By having the function as a gateway device, the relay device 5 can relay frames (data) between different communication protocols.

[0026] The relay device 5 functions as a microcomputer having a CPU 51 and a memory 52. ​​The memory 52 stores programs that enable the CPU 51 to execute predetermined functions. The memory 52 also stores a forwarding table (not shown). The forwarding table is a data table that indicates forwarding paths. Specifically, the forwarding table is a data table that associates the MAC address of a frame sender with the MAC address of a forwarding destination.

[0027] The relay device 5 realizes the functions of the following units by the CPU 51 executing the programs in the memory 52. ​​That is, the relay device 5 has functions as a time synchronization unit 53, a receiving unit 54, a determining unit 55, an assigning unit 56, a transmitting unit 57, and a list management unit 58.

[0028] The time synchronization unit 53 is configured to synchronize the time with other nodes that also have time synchronization units. The receiving unit 54 is configured to receive frames transmitted from a transmitting device.

[0029] The determination unit 55 is configured to determine whether a transmission time ST, which is the time when the transmitting device transmits the frame, is attached to the frame. Specifically, the determination unit 55 determines whether the transmission time ST is attached to the header of the frame received by the receiving unit 54.

[0030] The assigning unit 56 is configured to assign, to the frame as the transmission time ST, a pseudo transmission time that is based on the reception time that is the time when the frame is received by the receiving unit 54, when the determining unit 55 determines that the frame has not been assigned the transmission time ST. The transmission time assignment process performed by the determining unit 55 and the assigning unit 56 will be described in detail later.

[0031] The transmitting unit 57 is configured to forward frames based on the forwarding table. More specifically, the transmitting unit 57 is configured to transmit the frame received by the receiving unit 54 as is, or to transmit the frame to which the pseudo transmission time has been assigned by the assigning unit 56, to the receiving device.

[0032] Specifically, the transmitter 57 transmits four patterns of frames, namely, a first frame, a second frame, a third frame, and a fourth frame, to the receiving device. The first frame is a frame to which a transmission time ST has originally been assigned by the transmitting device. The second frame is a frame to which a pseudo transmission time ST is assigned, taking into account a propagation delay (described later). The third frame is a frame to which a pseudo transmission time ST is assigned, taking the reception time, which is the time when the receiving unit 54 receives the frame, as the reception time ST. The fourth frame is a frame to which a transmission time ST has not been assigned by the transmitting device, nor has a pseudo transmission time ST been assigned by the relay device 5. In other words, the first and fourth frames are frames transmitted from the transmitting device that are forwarded as is. On the other hand, the second and third frames are frames to which a pseudo transmission time ST has been assigned by the relay device 5.

[0033] The list management unit 58 is a storage device for recording a first recording list and a second recording list, which will be described later. Each of the ECUs 1 to 4 and the relay device 5 may include one microcomputer or multiple microcomputers.

[0034] The method for realizing the functions of each unit included in the ECUs 1 to 4 and the relay device 5 is not limited to software, and some or all of the functions may be realized using one or more pieces of hardware. For example, when the functions are realized by an electronic circuit that is hardware, the electronic circuit may be realized by a digital circuit, an analog circuit, or a combination of these.

[0035] [1-2. Processing] The transmission time assignment process executed by the relay device 5 will be described with reference to the flowcharts shown in Figures 3 and 4. Note that this transmission time assignment process is repeatedly executed while the ignition switch is on.

[0036] First, in S101, the receiving unit 54 of the relay device 5 receives a frame from the transmitting device. Next, in S102, the determination unit 55 of the relay device 5 determines whether or not a transmission time ST is added to the header of the frame. Specifically, the determination unit 55 determines whether or not a timestamp is set in the header of the frame.

[0037] If the determination unit 55 determines in S102 that the transmission time ST is not added to the frame header, the process proceeds to S103. On the other hand, if the determination unit 55 determines in S102 that the transmission time ST is added to the frame header, the process proceeds to S111, and the transmitter 57 of the relay device 5 transmits the frame received from the transmitter in S101 to the receiving device as is. In other words, the transmitter 57 transmits the first frame to the receiving device.

[0038] In S103, the relay device 5 determines whether the receiving device has a function for processing the information of the transmission time ST assigned to the frame. Specifically, the relay device 5 refers to the first record list recorded in the list management unit 58 and determines whether the receiving device is capable of processing the information of the transmission time ST. The first record list is a list that records whether the receiving device at the forwarding destination has a function for processing the information of the transmission time ST assigned to the frame. If the first record list records that the receiving device is capable of processing the information of the transmission time ST, the relay device 5 determines that the receiving device is capable of processing the information of the transmission time ST. The function for processing the information of the transmission time ST is, for example, a function for reading the timestamp of the transmission time ST.

[0039] If the relay device 5 determines in S103 that the receiving device is capable of processing the information of the transmission time ST, the process proceeds to S104. On the other hand, if the relay device 5 determines in S103 that the receiving device is not capable of processing the information of the transmission time ST, the process proceeds to S110. The relay device 5 does not assign a pseudo transmission time to the frame as the transmission time ST, but proceeds to S111, and the transmitter 57 transmits the frame received from the transmitting device in S101 as is to the receiving device. In other words, the transmitter 57 transmits the fourth frame to the receiving device.

[0040] In S104, the relay device 5 determines whether the receiving device requires information about the transmission time ST. Specifically, the relay device 5 refers to the second record list recorded in the list management unit 58 and determines whether the receiving device requires information about the transmission time ST. The second record list is a list that records, for the receiving device at the transfer destination, whether the receiving device requires information about the transmission time ST. If the second record list indicates that the receiving device requires information about the transmission time ST, the relay device 5 determines that the receiving device requires information about the transmission time ST. The requirement of information about the transmission time ST means, for example, that it is necessary to process data in chronological order by reading the timestamp of the transmission time ST.

[0041] If the relay device 5 determines in S104 that the receiving device requires information about the transmission time ST, the process proceeds to S105. On the other hand, if the relay device 5 determines in S104 that the receiving device does not require information about the transmission time ST, the process proceeds to S110. The relay device 5 does not assign a pseudo transmission time to the frame as the transmission time ST, but proceeds to S111, and the transmitter 57 transmits the frame received from the transmitting device in S101 to the receiving device as is. In other words, the transmitter 57 transmits the fourth frame to the receiving device.

[0042] In S105, the relay device 5 determines whether the transmitting device and the relay device 5 are time-synchronized. Specifically, the relay device 5 determines whether the transmitting device is a transmitting device that is communicating with the relay device 5 for time synchronization. If the transmitting device is a transmitting device that is communicating with the relay device 5 for time synchronization, the relay device 5 determines that the transmitting device and the relay device 5 are time-synchronized. Note that the relay device 5 may previously store a list of transmitting devices that directly or indirectly refer to global time for time synchronization, and may determine whether the transmitting device and the relay device 5 are time-synchronized by referring to the list.

[0043] If the relay device 5 determines in S105 that the transmission device and the relay device 5 are time-synchronized, the process proceeds to S106. On the other hand, if the relay device 5 determines in S105 that the transmission device and the relay device 5 are not time-synchronized, the process proceeds to S108.

[0044] In S106, the relay device 5 determines whether the frame includes control data. Control data is data corresponding to driving-related vehicle operations such as turning, driving, and stopping. For example, control data is used in a powertrain ECU, an ECU that realizes an autonomous driving function or a driving assistance function, etc. Control data may be integrated with other control data by a receiving device and used. In other words, multiple control data may be used in a so-called sensor fusion manner. In such cases, it is preferable that the multiple control data are sampled as close together as possible. In other words, it is preferable that the control data be linked to a more accurate transmission time ST. On the other hand, data other than control data includes data corresponding to multimedia functions such as audio and data corresponding to comfort functions such as air conditioning.

[0045] If the relay device 5 determines in S106 that the frame contains control data, the process proceeds to S107. On the other hand, if the relay device 5 determines in S106 that the frame does not contain control data, the process proceeds to S108.

[0046] Next, in S107, the relay device 5 sets the time that takes the propagation delay into consideration as the pseudo transmission time. Here, if the transmitting device and the relay device 5 are time-synchronized, the relay device 5 records the propagation delay in advance. As an example, the relay device 5 records in advance, as the propagation delay, the difference between the timestamp indicating the transmission time ST of the frame transmitted from the transmitting device and the timestamp indicating the reception time when the relay device 5 received the frame.

[0047] The relay device 5 determines the pseudo transmission time as the reception time minus the delay time (i.e., propagation delay) that is the time a signal is delayed in the communication path from the transmission device to the relay device 5. In cases where it is preferable to associate a more accurate transmission time ST with the control data, a time that takes into account the propagation delay time and is considered to be closer to the actual transmission time ST than the reception time that is the time when the receiver 54 of the relay device 5 receives the frame from the transmission device is used as the pseudo transmission time.

[0048] Meanwhile, in S108, the relay device 5 sets the reception time, which is the time when the receiver 54 actually receives the frame from the transmitting device, as the pseudo transmission time. If the transmitting device and the relay device 5 are not time-synchronized and the propagation delay time cannot be measured, or if the data can be used without strictly calculating the transmission time ST taking the propagation delay time into consideration, the reception time is used as the pseudo transmission time.

[0049] Next, in S109, the assigning unit 56 of the relay device 5 assigns a pseudo transmission time to the header of the frame. Specifically, the assigning unit 56 assigns the pseudo transmission time of S107 or the pseudo transmission time of S108 as the transmission time ST of the frame. In other words, the assigning unit 56 generates a second frame to which the pseudo transmission time of S107 has been assigned, or a third frame to which the pseudo transmission time of S108 has been assigned. Next, in S111, the transmitter 57 transmits the frame to the receiving device. That is, the transmitter 57 transmits any one of the first to fourth frames to the receiving device.

[0050] [1-3.Effects] According to the embodiment described above in detail, the following effects can be obtained.

[0051] (1a) In the above embodiment, if the relay device 5 determines that a frame does not have a transmission time ST, it assigns a pseudo transmission time to the frame as the transmission time ST. This configuration allows the relay device 5 to easily assign a transmission time ST to a frame transmitted by a transmitting device that does not have the function of assigning a transmission time ST to the frame's header. This allows the receiving device to process the frame taking into account information about the transmission time ST, making it easier to ensure consistency with other received frames.

[0052] (1b) In the above embodiment, when the relay device 5 determines that the transmitting device and the relay device 5 are not time-synchronized or when the relay device 5 determines that the frame does not contain control data, the relay device 5 sets the reception time, which is the time when the receiving unit 54 of the relay device 5 receives the frame from the transmitting device, as the pseudo transmission time. With this configuration, the relay device 5 can easily assign the transmission time ST.

[0053] In an in-vehicle network, the communication line connecting the transmitter and the relay device 5 is relatively short, so even if the reception time is used as the pseudo transmission time, it is unlikely to deviate significantly from the actual transmission time ST. Therefore, when the transmitter and the relay device 5 are not time-synchronized and the propagation delay cannot be measured, or when the control data does not require the transmission time ST to be calculated precisely taking the propagation delay into account, it is preferable to use the reception time as the pseudo transmission time because this allows the transmission time ST to be assigned more simply. An ECU that does not include a time synchronization unit or a transmission time assigning unit, such as the ECU 3, is assumed as the transmitter. In particular, when the transmitter and the relay device 5 communicate directly without going through another relay device 5, even if the reception time is used as the pseudo transmission time, the deviation from the actual transmission time ST is smaller.

[0054] (1c) In the above embodiment, if the relay device 5 determines that the transmitting device and the relay device 5 are time-synchronized and that the frame contains control data, the relay device 5 determines the time obtained by subtracting the delay time from the reception time as the pseudo-transmission time.

[0055] For example, a case may be assumed in which the transmitting device has a time synchronization function but does not have a function to assign a transmission time ST to a frame. That is, a transmitting device may be an ECU, such as ECU 2, that has a time synchronization unit 23 but does not have a transmission time assigning unit. As an example, a legacy ECU that does not have a function to assign a transmission time ST to a frame, or an inexpensive ECU that does not have a function to assign a transmission time ST to a frame in order to reduce costs, may be assumed. With the above-described configuration, the relay device 5 can easily assign a transmission time ST to a frame transmitted by such an ECU.

[0056] Furthermore, it is preferable that the control data be linked to a more accurate transmission time ST, but the relay device 5 can easily assign a more accurate transmission time ST because it uses a time that takes propagation delay into account as the pseudo transmission time. Therefore, the control data can be used for processing that requires real-time performance or fast response.

[0057] (1d) In the above embodiment, if the relay device 5 determines that the receiving device does not need information about the transmission time ST, the relay device 5 does not assign a pseudo transmission time to the frame. With this configuration, the relay device 5 can prevent unnecessary information from being transmitted to the receiving device.

[0058] (1e) In the above embodiment, if the relay device 5 determines that the receiving device does not have the function to process the information of the transmission time ST assigned to the frame, the relay device 5 does not assign a pseudo transmission time to the frame. With this configuration, the relay device 5 can prevent unnecessary information from being transmitted to the receiving device.

[0059] [1-4. Correspondence] In the above embodiment, the ECUs 1 to 3 correspond to the first communication device, and the ECU 4 corresponds to the second communication device.

[0060] 2. Other Embodiments Although the embodiments of the present disclosure have been described above, it goes without saying that the present disclosure is not limited to the above-described embodiments and can take on various forms.

[0061] (2a) In the above embodiment, when the relay device 5 determines in S106 that the frame does not contain control data, the relay device 5 sets the reception time as the pseudo-transmission time in S108. However, even when the relay device 5 determines in S106 that the frame does not contain control data, the relay device 5 may proceed to S107 and set the time obtained by subtracting the delay time from the reception time as the pseudo-transmission time.

[0062] (2b) In the above embodiment, the communication system 100 includes one relay device 5. However, the communication system 100 may include multiple relay devices. An additional relay device may be provided between the transmitting device and the relay device 5, or an additional relay device may be provided between the relay device 5 and the receiving device. As long as a forwarding table is recorded in each relay device and each relay device includes a time synchronization unit, each relay device may assign a pseudo transmission time to a frame transmitted from the transmitting device.

[0063] (2c) In the above embodiment, the ECUs 1 to 3 are connected in parallel to the relay device 5. However, the manner in which the transmitters are connected to the relay device 5 is not limited to this. For example, the transmitters may be connected to the relay device 5 in a multi-drop connection.

[0064] (2d) Each device (i.e., ECUs 1-4, relay device 5) and the method implemented by each device described in this disclosure may be implemented by a dedicated computer configured by configuring a processor and memory programmed to execute one or more functions embodied in a computer program. Alternatively, each device and the method implemented by each device described in this disclosure may be implemented by a dedicated computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, each device and the method implemented by each device described in this disclosure may be implemented by one or more dedicated computers configured by combining a processor and memory programmed to execute one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, a computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer. The method for implementing the functions of each unit included in each device does not necessarily need to include software; all of the functions may be implemented using one or more hardware.

[0065] (2e) Multiple functions possessed by one component in the above embodiments may be realized by multiple components, or one function possessed by one component may be realized by multiple components. Also, multiple functions possessed by multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Also, part of the configuration of the above embodiments may be omitted. Also, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[0066] (2f) In addition to the communication system 100 described above, the present disclosure can also be realized in various forms, such as each device that constitutes the communication system 100, a program for causing a computer to function as each device, a non-transient physical recording medium such as a semiconductor memory on which this program is recorded, and a communication method.

[0067] [Technical idea disclosed in this specification] [Item 1] A relay device (5) mounted on a vehicle and used in a communication system (100) configured to enable communication between a first communication device (1-3) and a second communication device (4), a receiver (54) configured to receive frames transmitted from the first communication device; a determination unit (55) configured to determine whether a transmission time, which is the time when the first communication device transmitted the frame, is assigned to the frame; an assigning unit (56) configured to assign a pseudo-transmission time, which is a time based on a reception time that is a time when the receiving unit receives the frame, as the transmission time to the frame received by the receiving unit when the determining unit determines that the transmission time has not been assigned to the frame; a transmitting unit (57) configured to transmit the frame to which the pseudo transmission time has been assigned by the assigning unit to the second communication device; A relay device comprising:

[0068] [Item 2] The relay device according to item 1, The relay device is configured such that the granting unit sets the reception time as the pseudo transmission time.

[0069] [Item 3] The relay device according to item 1 or 2, The relay device is configured such that the granting unit sets the pseudo transmission time to the time obtained by subtracting a delay time, which is the time a signal is delayed in a communication path from the first communication device to the relay device, from the reception time.

[0070] [Item 4] The relay device according to any one of items 1 to 3, the assigning unit is configured to determine whether the second communication device requires the information of the transmission time by referring to a list in which information as to whether the second communication device requires the information of the transmission time is recorded in advance, and when it is determined that the second communication device does not require the information of the transmission time, not assign the pseudo transmission time to the frame as the transmission time; The relay device is configured such that the transmitter transmits the frame received by the receiver to the second communication device.

[0071] [Item 5] Item 4: A relay device according to any one of items 1 to 4, the assigning unit is configured to determine whether the second communication device has a function to process the information of the transmission time assigned to the frame by referring to a list in which information as to whether the second communication device has a function to process the information of the transmission time assigned to the frame is pre-recorded, and when it is determined that the second communication device does not have the function to process the information of the transmission time assigned to the frame, not assign the pseudo transmission time to the frame as the transmission time; The relay device is configured such that the transmitter transmits the frame received by the receiver to the second communication device. [Explanation of symbols]

[0072] 1 to 4...ECU, 5...relay device, 54...receiving unit, 55...determining unit, 56...granting unit, 57...transmitting / receiving unit, 57...transmitting unit, 100...communication system.

Claims

1. A relay device (5) mounted on a vehicle and used in a communication system (100) configured to enable communication between a first communication device (1-3) and a second communication device (4), a receiver (54) configured to receive frames transmitted from the first communication device; a determination unit (55) configured to determine whether a transmission time, which is the time when the first communication device transmitted the frame, is assigned to the frame; an assigning unit (56) configured to assign a pseudo-transmission time, which is a time based on a reception time that is a time when the receiving unit received the frame, as the transmission time to the frame received by the receiving unit when the determining unit determines that the transmission time has not been assigned to the frame; a transmitting unit (57) configured to transmit the frame to which the pseudo transmission time has been assigned by the assigning unit to the second communication device; A relay device comprising:

2. The relay device according to claim 1, The relay device is configured such that the granting unit sets the reception time as the pseudo transmission time.

3. The relay device according to claim 1, The relay device is configured such that the granting unit sets the pseudo transmission time to the time obtained by subtracting a delay time, which is the time a signal is delayed in a communication path from the first communication device to the relay device, from the reception time.

4. 3. The relay device according to claim 1, the assigning unit is configured to determine whether the second communication device requires the information of the transmission time by referring to a list in which information as to whether the second communication device requires the information of the transmission time is recorded in advance, and when it is determined that the second communication device does not require the information of the transmission time, not assign the pseudo transmission time to the frame as the transmission time; The relay device is configured such that the transmitter transmits the frame received by the receiver to the second communication device.

5. 3. The relay device according to claim 1, the assigning unit is configured to determine whether the second communication device has a function to process the information of the transmission time assigned to the frame by referring to a list in which information as to whether the second communication device has a function to process the information of the transmission time assigned to the frame is pre-recorded, and when it is determined that the second communication device does not have the function to process the information of the transmission time assigned to the frame, not assign the pseudo transmission time to the frame as the transmission time; The relay device is configured such that the transmitter transmits the frame received by the receiver to the second communication device.

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