Vehicle-mounted relay device, vehicle-mounted device, and hibernation notification method

Abstract

A vehicle-mounted relay device includes a relay section that relays information between a plurality of vehicle-mounted devices belonging to mutually different VLANs (Virtual Local Area Networks); a detection section that detects a case where the vehicle-mounted devices have transitioned to a sleep state; and a notification section that, in a case where the detection section detects that a first vehicle-mounted device among the plurality of vehicle-mounted devices has transitioned to a sleep state, makes a sleep notification to a second vehicle-mounted device among the plurality of vehicle-mounted devices indicating that the first vehicle-mounted device has transitioned to a sleep state.

Description

Technical Field

[0001] This disclosure relates to vehicle-mounted relay devices, vehicle-mounted devices, and sleep notification methods.

[0002] This application claims priority based on Japanese Patent Application No. 2021-107615, filed on June 29, 2021, the entire disclosure of which is incorporated herein by reference. Background Technology

[0003] Patent Document 1 (Japanese Patent Application Publication No. 2020-88568) discloses the following electronic control device. That is, the electronic control device is any one of a plurality of electronic control devices constituting an in-vehicle network system and capable of communicating with each other. This electronic control device includes: a first communication control unit configured to control communication with other electronic control devices based on CAN (registered trademark); and a second communication control unit configured to control communication with the other electronic control devices based on Ethernet (registered trademark). If the CAN communication state controlled by the first communication control unit is in a wake-up state, then the Ethernet communication state with the other electronic control devices is set to be communicable; if the CAN communication state controlled by the first communication control unit is in a sleep state, then the Ethernet communication state with the other electronic control devices is set to be non-communicable.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-88568 Summary of the Invention

[0007] The vehicle-mounted relay device disclosed herein includes: a relay unit for relaying information between multiple vehicle-mounted devices belonging to different VLANs (Virtual Local Area Networks); a detection unit for detecting when the vehicle-mounted devices have entered a sleep state; and a notification unit for notifying a second vehicle-mounted device among the multiple vehicle-mounted devices when the detection unit detects that a first vehicle-mounted device among the multiple vehicle-mounted devices has entered a sleep state, the sleep notification indicating that the first vehicle-mounted device has entered a sleep state.

[0008] The vehicle-mounted device disclosed herein includes: a transmitting unit that transmits information to other vehicle-mounted devices belonging to different VLANs via a vehicle-mounted relay device; and a receiving unit that receives a sleep notification from the vehicle-mounted relay device indicating that the other vehicle-mounted devices have entered a sleep state, wherein, upon receiving the sleep notification, the transmitting unit stops transmitting information to the other vehicle-mounted devices.

[0009] The hibernation notification method disclosed herein includes the following steps: relaying information between multiple vehicle-mounted devices belonging to different VLANs; detecting that a first vehicle-mounted device among the multiple vehicle-mounted devices has entered a hibernation state; and sending a hibernation notification to a second vehicle-mounted device among the multiple vehicle-mounted devices, the hibernation notification indicating that the first vehicle-mounted device has entered a hibernation state.

[0010] One embodiment of this disclosure can be implemented not only as a vehicle-mounted relay device with such a characteristic processing unit, but also as a program for causing a computer to execute the characteristic processing steps, or as implementing part or all of the semiconductor integrated circuits of the vehicle-mounted relay device, or as a vehicle-mounted communication system including the vehicle-mounted relay device. Furthermore, one embodiment of this disclosure can be implemented not only as a vehicle-mounted device with such a characteristic processing unit, but also as a communication method using the characteristic processing as a step, or as a program for causing a computer to execute the step, or as implementing part or all of the semiconductor integrated circuits of the vehicle-mounted device, or as a vehicle-mounted communication system including the vehicle-mounted device. Attached Figure Description

[0011] Figure 1 This is a diagram illustrating the structure of an in-vehicle communication system according to an embodiment of the present disclosure.

[0012] Figure 2 This is a diagram illustrating the structure of an on-board ECU according to an embodiment of the present disclosure.

[0013] Figure 3 This is a diagram illustrating the structure of a relay device according to an embodiment of the present disclosure.

[0014] Figure 4 This diagram illustrates an example of a notification table stored in the storage unit of a relay device according to an embodiment of this disclosure.

[0015] Figure 5 This is a flowchart illustrating an example of the operational steps of a relay device performing relay processing according to an embodiment of this disclosure.

[0016] Figure 6 This is a flowchart illustrating an example of the operational steps taken by a relay device according to an embodiment of this disclosure when issuing a sleep notification.

[0017] Figure 7 This is a flowchart illustrating an example of the operational steps taken by an in-vehicle ECU according to an embodiment of this disclosure when transmitting information to other in-vehicle ECUs.

[0018] Figure 8This is a diagram illustrating an example of the communication sequence in a vehicle communication system according to an embodiment of the present disclosure. Detailed Implementation

[0019] In recent years, the amount of communication in vehicular communication systems has been increasing, for example, due to communication used for autonomous driving control. To alleviate the strain on communication frequency bands in vehicular communication systems, it is desirable to minimize the amount of communication in these systems without affecting the functionality of the onboard devices.

[0020] [The problem this disclosure aims to solve]

[0021] A technology that is expected to further reduce the amount of communication in a vehicle communication system, exceeding the technology described in Patent Document 1.

[0022] This disclosure was made to solve the above-mentioned problems, and its purpose is to provide an in-vehicle relay device, an in-vehicle device, and a sleep notification method that can further reduce the amount of communication in an in-vehicle communication system.

[0023] [The Effects of This Disclosure]

[0024] According to this disclosure, the amount of communication in the vehicle communication system can be further reduced.

[0025] [Description of embodiments of this disclosure]

[0026] First, the contents of the embodiments of this disclosure will be described.

[0027] (1) The vehicle relay device according to the embodiments of the present disclosure includes: a relay unit for relaying information between multiple vehicle devices belonging to different VLANs, i.e., virtual local area networks; a detection unit for detecting when the vehicle devices change to a sleep state; and a notification unit for sending a sleep notification to a second vehicle device among the multiple vehicle devices when the detection unit detects that a first vehicle device among the multiple vehicle devices has changed to a sleep state, the sleep notification indicating that the first vehicle device has changed to a sleep state.

[0028] In this way, by detecting when a vehicle-mounted device enters a sleep state in the vehicle-mounted relay device and sending a sleep notification to other vehicle-mounted devices belonging to a different VLAN, indicating that the vehicle-mounted device has entered a sleep state, the other vehicle-mounted devices can be aware that the vehicle-mounted device has entered a sleep state. Therefore, for example, the transmission of information from the other vehicle-mounted devices to the vehicle-mounted device can be stopped during the period when the vehicle-mounted device is in a sleep state. As a result, the communication volume in the vehicle-mounted communication system can be further reduced.

[0029] (2) Alternatively, if the first NM (Network Management) message, which is periodically broadcast by the first vehicle device within the VLAN to which the first vehicle device belongs, does not arrive within a specified time, the detection unit determines that the first vehicle device has entered a dormant state, and the first NM message indicates that the first vehicle device is in an active state.

[0030] Based on this structure, it is possible to use NM messages, which are based on the existing standard AUTOSAR (AUTOmotive OpenSystem Architecture), to easily and correctly detect the first onboard device transitioning to a dormant state.

[0031] (3) Alternatively, if the first NM message does not arrive within a specified time, the detection unit determines whether the first vehicle-mounted device has switched to a sleep state or has malfunctioned.

[0032] Based on this structure, if the first NM message from the first vehicle-mounted device does not arrive within a specified time, it is possible to determine whether the first vehicle-mounted device has transitioned to a sleep state or whether the first vehicle-mounted device is malfunctioning, and to perform corresponding processing based on the determination result.

[0033] (4) Alternatively, the vehicle relay device may also include a storage unit that stores notification information, which indicates the correspondence between a group of vehicle devices belonging to different VLANs and whether a hibernation notification needs to be sent to another vehicle device in the group when one of the vehicle devices in the group goes into hibernation mode.

[0034] Based on this structure, it is possible to selectively send sleep notifications to vehicle devices that should be notified, based on whether notification information is stored in the storage unit. Therefore, for example, it is possible to send sleep notifications to vehicle devices that periodically send information to vehicle devices that have entered a sleep state.

[0035] (5) Alternatively, the second vehicle-mounted device may be a sensor, and the first vehicle-mounted device may be a driving assistance device that provides driving assistance based on the measurement results of the sensor.

[0036] In driver assistance systems, sensors send measurement results to the driver assistance device in short cycles. The driver assistance device frequently transitions to a sleep state when the vehicle is stopped. By enabling the sensors to recognize when the driver assistance device transitions to a sleep state, the transmission of measurement information from the sensors to the driver assistance device during the sleep state period can be stopped, thereby more effectively reducing the communication load in the vehicle communication system.

[0037] (6) Alternatively, the vehicle relay device may also include a transmitting unit that periodically sends a second NM message, i.e. a second network management message, to each of the vehicle relay devices, indicating that the vehicle relay device is in an active state. After the detection unit detects that the first vehicle device has changed to a sleep state, the transmitting unit also continues to send the second NM message to the second vehicle device. The notification unit notifies the second vehicle device of the sleep state by including the information indicating that the first vehicle device has changed to a sleep state in the second NM message sent by the transmitting unit.

[0038] Based on this structure, compared to a separate structure that generates a message indicating that the first vehicle-mounted device has switched to a sleep state and sends it to the second vehicle-mounted device, a sleep notification to the second vehicle-mounted device can be performed through simple processing.

[0039] (7) The vehicle-mounted device involved in the embodiments of this disclosure is a vehicle-mounted device comprising: a transmitting unit that transmits information to other vehicle-mounted devices belonging to different VLANs via a vehicle-mounted relay device; and a receiving unit that receives a sleep notification from the vehicle-mounted relay device indicating that the other vehicle-mounted device has changed to a sleep state, and when the receiving unit receives the sleep notification, the transmitting unit stops transmitting information to the other vehicle-mounted devices.

[0040] In this way, by receiving a sleep notification from the vehicle relay device indicating that another vehicle device belonging to a different VLAN has switched to a sleep state, and stopping the transmission of information to that other vehicle device, it is possible to stop the transmission of information to that other vehicle device during the period when that other vehicle device cannot receive information. This further reduces the communication load in the vehicle communication system.

[0041] (8) Alternatively, the sending unit may periodically broadcast an NM message indicating that the vehicle device is in an active state within the VLAN to which the vehicle device belongs, and the sending unit may continue to broadcast the NM message after the receiving unit receives the sleep notification.

[0042] Based on this structure, vehicle relay devices can recognize that the vehicle device is active and maintain the ability to receive information from other vehicle devices via the vehicle relay device.

[0043] (9) The hibernation notification method according to the embodiments of this disclosure includes the following steps: relaying information between multiple vehicle devices belonging to different VLANs; detecting that a first vehicle device among the multiple vehicle devices has changed to a hibernation state; and sending a hibernation notification to a second vehicle device among the multiple vehicle devices indicating that the first vehicle device has changed to a hibernation state.

[0044] Thus, by detecting when a vehicle-mounted device enters a sleep state in the vehicle-mounted relay device and sending a sleep notification to other vehicle-mounted devices belonging to a different VLAN, indicating that the vehicle-mounted device has entered a sleep state, these other vehicle-mounted devices can be made aware that the vehicle-mounted device has entered a sleep state. Therefore, for example, the transmission of information from these other vehicle-mounted devices to the vehicle-mounted device can be stopped during the period when the vehicle-mounted device is in a sleep state. As a result, the traffic in the vehicle-mounted communication system can be further reduced.

[0045] Hereinafter, embodiments of the present disclosure will be described using the accompanying drawings. Furthermore, the same or equivalent parts in the drawings will be labeled with the same reference numerals without repeating their descriptions. Additionally, at least some of the embodiments described below may be combined arbitrarily.

[0046] [Structure and Basic Movements]

[0047] Figure 1 This is a diagram illustrating the structure of a vehicle-mounted communication system according to an embodiment of the present disclosure. (Refer to...) Figure 1 The vehicle communication system 301 includes a relay device 101 and vehicle-mounted ECUs (Electronic Control Units) 111A, 111B, 111C, and 111D. Hereinafter, vehicle-mounted ECUs 111A, 111B, 111C, and 111D will also be referred to as vehicle-mounted ECU 111. The relay device 101 is an example of a vehicle-mounted relay device. The vehicle-mounted ECU 111 is an example of a vehicle-mounted device. The vehicle communication system 301 is mounted on a vehicle 1. That is, the relay device 101 and the vehicle-mounted ECU 111 are mounted on the vehicle 1.

[0048] The vehicle communication system 301 is not limited to having one relay device 101, but may also have two or more relay devices 101. In addition, the vehicle communication system 301 is not limited to having four vehicle ECUs 111, but may also have two, three or five or more vehicle ECUs 111.

[0049] The relay device 101 is connected to the vehicle ECUs 111A, 111B, 111C, and 111D via cable 2. Cable 2 is, for example, an Ethernet cable. The relay device 101, the vehicle ECU 111, and cable 2 constitute the vehicle network.

[0050] For example, vehicle ECUs 111A and 111B belong to VLAN 10, vehicle ECUs 111C and 111D belong to VLAN 20, and relay device 101 belongs to both VLAN 10 and VLAN 20.

[0051] The relay device 101 can relay information between multiple vehicle ECUs 111 belonging to the same VLAN in the vehicle network. Specifically, the relay device 101 relays information between vehicle ECU 111A and vehicle ECU 111B, and relays information between vehicle ECU 111C and vehicle ECU 111D.

[0052] Furthermore, the relay device 101 can relay information between multiple vehicle ECUs 111 belonging to different VLANs in the vehicle network. Specifically, the relay device 101, for example, relays information between vehicle ECU 111A and vehicle ECU 111C.

[0053] Vehicle ECU111 includes, for example, electric power steering (EPS), brake control device, accelerator control device, steering control device, driver assistance device in Advanced Driver-Assistance System (ADAS) that provides instructions for various devices, IVI (In-Vehicle Infotainment) device with functions such as audio playback and car navigation, or sensors such as cameras.

[0054] As an example, vehicle ECU 111A is a sensor. This sensor can be a vehicle speed sensor that measures the speed of vehicle 1, or a camera that captures images of the surroundings of vehicle 1. Additionally, vehicle ECU 111B is an IVI (Inter-Vehicle Detection and Control) device. Vehicle ECU 111C is a driver assistance device. Vehicle ECU 111D is a steering control device. Vehicle ECU 111A is an example of a second vehicle-mounted device. Vehicle ECU 111C is an example of a first vehicle-mounted device.

[0055] The vehicle-mounted ECU 111A, acting as a sensor, periodically generates Ethernet frames containing measurement information representing measurement results and transmits these Ethernet frames to the vehicle-mounted ECU 111C via relay device 101. The vehicle-mounted ECU 111C receives the Ethernet frames from the vehicle-mounted ECU 111A via relay device 101 and obtains the measurement information from the received Ethernet frames. The vehicle-mounted ECU 111C, acting as a driving assistance device, performs driving assistance based on the measurement results shown by the obtained measurement information.

[0056] In addition, the vehicle communication system 301 may also replace part or all of the vehicle ECUs 111A, 111B, 111C, and 111D, or may have a structure that includes other vehicle devices such as braking control devices and accelerator control devices in addition to the vehicle ECUs 111A, 111B, 111C, and 111D.

[0057] When the vehicle ECU 111 is in the active state, it transitions from the active state to the sleep state when the state of vehicle 1 meets the prescribed sleep conditions. Conversely, when the vehicle ECU 111 is in the sleep state, it transitions from the sleep state to the active state when the state of vehicle 1 meets the prescribed wake-up conditions. Here, the sleep state refers to a state where power consumption is lower than in the active state due to factors such as the cessation of some functions of the vehicle ECU 111, the cessation of power supply to the vehicle ECU 111, or the reduction of the clock frequency in the vehicle ECU 111. The sleep state is also referred to as standby power mode, standby state, power-saving state, or standby state. The active state is also referred to as normal start state, normal operation state, or non-sleep state.

[0058] The sleep conditions for the vehicle ECU 111 include, for example, when the vehicle 1 stops, when the speed of the vehicle 1 is less than a specified value, and when the power to the vehicle 1 is disconnected. The wake-up conditions for the vehicle ECU 111 include, for example, when the vehicle 1 starts moving, when the speed of the vehicle 1 reaches or exceeds a specified value, and when the power to the vehicle 1 is turned on. For example, the vehicle ECU 111 transitions from a sleep state to an active state and from an active state to a sleep state based on the sleep and wake-up conditions preset for each vehicle ECU 111.

[0059] For example, when the vehicle ECU111 is active, it periodically broadcasts AUTOSAR-compliant NM messages within its own VLAN. Specifically, the vehicle ECU111 broadcasts Ethernet frames containing NM messages within its own VLAN.

[0060] Additionally, for example, when the relay device 101 is in an active state, it periodically sends AUTOSAR-compliant NM messages to the vehicle ECU 111. Specifically, the relay device 101 sends Ethernet frames containing NM messages to the vehicle ECU 111.

[0061] When the relay device 101 is in an active state, for example, when the arrival of NM messages from all vehicle ECUs 111 ceases, it transitions from an active state to a sleep state. Conversely, when the relay device 101 is in a sleep state, for example, when it receives an NM message from at least one vehicle ECU 111, it transitions from a sleep state to an active state.

[0062] Figure 2 This is a diagram illustrating the structure of an on-board ECU according to an embodiment of this disclosure. (Refer to...) Figure 2The vehicle-mounted ECU 111 includes a communication port 11, a transmitter 12, a receiver 13, a processor 14, and a storage unit 15. The transmitter 12, receiver 13, and processor 14 are implemented, for example, by a processor such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor). The storage unit 15 is, for example, a non-volatile memory.

[0063] Communication port 11 is, for example, a terminal that can connect to cable 2. Alternatively, communication port 11 can also be a terminal of an integrated circuit. Communication port 11 is connected to relay device 101 via cable 2.

[0064] The processing unit 14 generates information to be sent to other vehicle ECUs 111 and outputs the generated information to the transmitting unit 12. Specifically, for example, the processing unit 14 in the vehicle ECU 111A, which is a sensor, generates measurement information representing the measurement result and outputs it to the transmitting unit 12 at a transmission timing that is scheduled according to a predetermined period.

[0065] The transmitting unit 12 sends information to other vehicle ECUs 111 belonging to different VLANs via the relay device 101. More specifically, the transmitting unit 12 in vehicle ECU 111A receives measurement information from the processing unit 14, generates an Ethernet frame containing the received measurement information, and sends the generated Ethernet frame to vehicle ECU 111C belonging to VLAN 20 via the communication port 11 and the relay device 101. Alternatively, the transmitting unit 12 can also send an Ethernet frame containing information received from the processing unit 14 to vehicle ECUs 111 belonging to the same VLAN 10 via the communication port 11 and the relay device 101.

[0066] The receiving unit 13 receives Ethernet frames from other vehicle ECUs 111 via the relay device 101 and the communication port 11, obtains information from the received Ethernet frames, and outputs it to the processing unit 14. Specifically, for example, the receiving unit 13 in the vehicle ECU 111C, which is a driver assistance device, receives Ethernet frames from the vehicle ECU 111A via the relay device 101 and the communication port 11, obtains measurement information from the received Ethernet frames, and outputs it to the processing unit 14.

[0067] The processing unit 14 stores the information received from the receiving unit 13 in the storage unit 15 and processes the information stored in the storage unit 15. Specifically, for example, the processing unit 14 in the vehicle ECU 111C, which is a driving assistance device, generates control information for driving assistance based on the measurement information received from the receiving unit 13, and sends the generated control information to other vehicle devices such as the accelerator control device via the transmitting unit 12, the communication port 11, and the relay device 101.

[0068] For example, the transmitting unit 12 periodically broadcasts an NM message indicating that its own vehicle ECU 111 is active within the VLAN to which its vehicle ECU 111 belongs. More specifically, when its own vehicle ECU 111 is active, the transmitting unit 12 periodically generates an Ethernet frame containing the broadcast address as the destination IP address and the NM message, and sends the generated Ethernet frame to the relay device 101 via communication port 11. The NM message broadcast by the transmitting unit 12 is an example of a first NM message.

[0069] For example, the storage unit 15 stores the sleep conditions and wake-up conditions of the vehicle ECU 111.

[0070] When the vehicle ECU 111 is in an active state, the processing unit 14, upon detecting that the state of the vehicle 1 meets the sleep conditions stored in the storage unit 15, causes the vehicle ECU 111 to change from an active state to a sleep state. For example, the processing unit 14 causes the vehicle ECU 111 to change from an active state to a sleep state after a predetermined time has elapsed since detecting that the state of the vehicle 1 meets the sleep conditions.

[0071] More specifically, after a predetermined time has elapsed since the detection that the state of vehicle 1 meets the sleep conditions, the processing unit 14 stops generating information that should be sent to other vehicle ECUs 111. Furthermore, when the processing unit 14 detects that the state of vehicle 1 meets the sleep conditions, it outputs a receive stop instruction to the receiving unit 13 and a send stop instruction to the sending unit 12.

[0072] When the receiving unit 13 receives a receiving stop instruction from the processing unit 14, it stops receiving Ethernet frames from the relay device 101 after a predetermined time has elapsed since receiving the receiving stop instruction.

[0073] Upon receiving a transmission stop instruction from the processing unit 14, the transmitting unit 12 stops the periodic broadcasting of NM messages after a predetermined time has elapsed since receiving the transmission stop instruction. For example, during the period from receiving the transmission stop instruction until the predetermined time has elapsed, the transmitting unit 12 broadcasts one or more NM messages containing transition information indicating a change to a sleep state. As another example, during the period from receiving the transmission stop instruction until the predetermined time has elapsed, the transmitting unit 12 broadcasts the last broadcast NM message containing the transition information.

[0074] In addition, when the vehicle ECU 111 is in a dormant state, the processing unit 14 detects that the state of the vehicle 1 meets the wake-up conditions in the storage unit 15 and causes the vehicle ECU 111 to change from a dormant state to an active state.

[0075] More specifically, when the processing unit 14 detects that the state of vehicle 1 meets the wake-up conditions, it begins to generate information to be sent to other vehicle ECUs 111. Additionally, when the wake-up conditions of vehicle 1 are met, it outputs a receive start instruction to the receiving unit 13 and a send start instruction to the sending unit 12.

[0076] When the receiving unit 13 receives a reception start instruction from the processing unit 14, it transitions to a waiting state, which is capable of receiving Ethernet frames from the relay device 101.

[0077] Upon receiving a transmission start instruction from the processing unit 14, the transmitting unit 12 begins the periodic broadcasting of NM messages.

[0078] Figure 3 This is a diagram illustrating the structure of the relay device according to an embodiment of this disclosure. (Refer to...) Figure 3 The relay device 101 includes four communication ports 21, a relay unit 22, a detection unit 23, an NM transmission unit 24, a notification unit 25, and a storage unit 26. Furthermore, the relay device 101 is not limited to a structure with four communication ports 21; it may also have two, three, or five or more communication ports 21. The relay unit 22, detection unit 23, NM transmission unit 24, and notification unit 25 are implemented, for example, by a processor such as a CPU or DSP. The storage unit 26 is, for example, a non-volatile memory.

[0079] Communication port 21 is, for example, a terminal that can connect to cable 2. Alternatively, communication port 21 can also be a terminal of an integrated circuit. For example, four communication ports 21 are respectively connected to four vehicle ECUs 111.

[0080] The storage unit 26 stores an address table that represents the correspondence between the source IP (Internet Protocol) address and destination IP address contained in the Ethernet frames that can be received from the vehicle ECU 111 and the port number of the communication port 21.

[0081] The relay unit 22 relays information between multiple vehicle ECUs 111. That is, the relay unit 22 performs relay processing to receive Ethernet frames from the vehicle ECUs 111 via the communication port 21 and relay the received Ethernet frames.

[0082] More specifically, the relay unit 22 obtains the source IP address and destination IP address from the received Ethernet frame. Referring to the address table in the storage unit 26, the relay unit 22 determines the port number corresponding to the obtained source IP address and destination IP address. Then, the relay unit 22 transmits the Ethernet frame to the destination vehicle ECU 111 via the communication port 21 with the determined port number.

[0083] The relay unit 22 relays information between multiple vehicle ECUs 111 belonging to different VLANs in the vehicle network. Specifically, for example, the relay unit 22 receives Ethernet frames from the vehicle ECU 111 belonging to VLAN 10 via the corresponding communication port 21, and sends the received Ethernet frames to the destination vehicle ECU 111 belonging to VLAN 20 via the communication port 21 with the port number corresponding to the source IP address and destination IP address. Alternatively, for example, the relay unit 22 receives Ethernet frames from the vehicle ECU 111 belonging to VLAN 20 via the corresponding communication port 21, and sends the received Ethernet frames to the destination vehicle ECU 111 belonging to VLAN 10 via the communication port 21 with the port number corresponding to the source IP address and destination IP address.

[0084] The relay unit 22 relays information between multiple vehicle ECUs 111 belonging to the same VLAN in the vehicle network. Specifically, for example, the relay unit 22 receives Ethernet frames from a vehicle ECU 111 belonging to VLAN 10 via the corresponding communication port 21, and sends the received Ethernet frames to the destination vehicle ECU 111 belonging to VLAN 10 via the communication port 21 with the port number corresponding to the source IP address and destination IP address. Alternatively, for example, the relay unit 22 receives Ethernet frames from a vehicle ECU 111 belonging to VLAN 20 via the corresponding communication port 21, and sends the received Ethernet frames to the destination vehicle ECU 111 belonging to VLAN 20 via the communication port 21 with the port number corresponding to the source IP address and destination IP address.

[0085] When the destination IP address of an Ethernet frame received from a vehicle ECU 111 belonging to VLAN 10 is a broadcast address, the relay unit 22 transmits the Ethernet frame to other vehicle ECUs 111 belonging to VLAN 10 via communication port 21, which corresponds to the port number of the source IP address and the broadcast address. The relay unit 22 also assigns a timestamp to the Ethernet frame and outputs it to the detection unit 23. Furthermore, when the destination IP address of an Ethernet frame received from a vehicle ECU 111 belonging to VLAN 20 is a broadcast address, the relay unit 22 transmits the Ethernet frame to other vehicle ECUs 111 belonging to VLAN 20 via communication port 21, which corresponds to the port number of the source IP address and the broadcast address. The relay unit 22 also assigns a timestamp to the Ethernet frame and outputs it to the detection unit 23.

[0086] The detection unit 23 detects when the vehicle ECU 111 enters a sleep state. For example, if the NM message that is periodically broadcast by the vehicle ECU 111 within the VLAN to which the vehicle ECU 111 belongs does not arrive within the specified time, the detection unit 23 determines that the vehicle ECU 111 has entered a sleep state.

[0087] More specifically, the detection unit 23 receives Ethernet frames from the relay unit 22. If the received Ethernet frame contains an NM message, the detection unit 23 obtains the source IP address, the NM message, and the timestamp from the Ethernet frame. The detection unit 23 establishes a correspondence between the obtained NM message, the vehicle ECU 111 represented by the obtained source IP address, and the reception time represented by the obtained timestamp, and stores them in the storage unit 26.

[0088] The detection unit 23 refers to the NM message stored in the storage unit 26 and determines that the vehicle ECU 111 has entered a sleep state if the NM message from a certain vehicle ECU 111 has not arrived within a specified time.

[0089] For example, if the NM message from the vehicle ECU 111 does not arrive within the specified time, the detection unit 23 determines whether the vehicle ECU 111 has switched to a dormant state or whether the vehicle ECU 111 has malfunctioned.

[0090] More specifically, if an NM message from a certain vehicle ECU 111 does not arrive within a specified time, and the latest NM message from that vehicle ECU 111 contains change information, the detection unit 23 determines that the vehicle ECU 111 has entered a dormant state.

[0091] On the other hand, if an NM message from a certain vehicle ECU 111 does not arrive within the specified time, and if the latest NM message from that vehicle ECU 111 does not contain change information, the detection unit 23 determines that the vehicle ECU 111 has malfunctioned.

[0092] When the detection unit 23 determines that a certain vehicle ECU 111 has entered a sleep state, it notifies the NM sending unit 24 and the notification unit 25 of the sleep determination information indicating that the vehicle ECU 111 has entered a sleep state.

[0093] The NM transmitting unit 24 periodically sends NM messages to each vehicle ECU 111 indicating that the relay device 101 is active. The NM message sent by the NM transmitting unit 24 is an example of the second NM message.

[0094] More specifically, when the relay device 101 is in an active state, the NM transmitting unit 24 periodically generates Ethernet frames containing NM messages to be sent to each vehicle ECU 111, and outputs the generated Ethernet frames to the relay unit 22.

[0095] The relay unit 22 receives an Ethernet frame containing an NM message from the NM transmission unit 24 and sends the received Ethernet frame to the vehicle ECU 111 via the communication port 21 with the port number corresponding to the destination IP address.

[0096] For example, when the detection unit 23 detects that the vehicle ECU 111 has entered a sleep state, the NM sending unit 24 stops sending NM messages to the vehicle ECU 111. On the other hand, even after the detection unit 23 detects that the vehicle ECU 111 has entered a sleep state, it continues to send NM messages to vehicle ECUs other than the vehicle ECU 111.

[0097] More specifically, when the sleep determination information is received from the detection unit 23, the NM transmission unit 24 stops generating the Ethernet frame containing the NM message to be sent to the vehicle ECU 111 as indicated by the received sleep determination information.

[0098] When the detection unit 23 detects that an on-board ECU 111 belonging to a certain VLAN has changed to a sleep state, the notification unit 25 sends a sleep notification to other on-board ECUs 111 belonging to other VLANs, indicating that the on-board ECU 111 has changed to a sleep state.

[0099] More specifically, when the detection unit 23 receives hibernation determination information, the notification unit 25 issues a hibernation notification based on the received hibernation determination information.

[0100] Figure 4 This diagram illustrates an example of a notification / notification table stored in the storage unit of a relay device according to an embodiment of this disclosure. (See also...) Figure 4 Storage unit 26 stores a notification table Tb1, which represents the correspondence between groups of vehicle ECUs 111 belonging to different VLANs and whether a hibernation notification needs to be sent to another vehicle ECU 111 in the same group when one vehicle ECU 111 in the group goes into hibernation mode. Notification table Tb1 is an example of notification information.

[0101] When the detection unit 23 receives the hibernation determination information, the notification unit 25 refers to the notification table Tb1 in the storage unit 26 to decide whether to send a hibernation notification to other vehicle ECUs 111 in the group that includes the vehicle ECU 111 shown in the received hibernation determination information.

[0102] As an example, when the notification unit 25 receives hibernation determination information from the detection unit 23 indicating that the vehicle ECU 111C has changed to a hibernation state, it refers to the notification table Tb1 and decides to send a hibernation notification to the vehicle ECU 111A in group P1, which includes the vehicle ECU 111C, while deciding not to send a hibernation notification to the vehicle ECU 111B in group P3, which includes the vehicle ECU 111C.

[0103] For example, the notification unit 25 notifies the vehicle ECU 111A of its sleep state by including information indicating that the vehicle ECU 111C has switched to a sleep state in an NM message sent by the NM transmission unit 24.

[0104] More specifically, the notification unit 25 outputs a notification instruction to the NM transmission unit 24 indicating that the vehicle ECU 111A should be notified to switch the vehicle ECU 111C to a sleep state.

[0105] The NM transmitting unit 24 receives a notification instruction from the notification unit 25 and generates an NM message containing hibernation information SL indicating that the vehicle ECU 111C has switched to hibernation mode. Then, the NM transmitting unit 24 generates an Ethernet frame containing the generated NM message and sends it to the vehicle ECU 111A, and transmits the generated Ethernet frame to the vehicle ECU 111A via the relay unit 22 and the communication port 21.

[0106] Refer again Figure 2 The receiving unit 13 in the vehicle ECU 111A receives a sleep notification from the relay device 101 indicating that the vehicle ECU 111C has switched to sleep mode. More specifically, the receiving unit 13 receives an Ethernet frame from the relay device 101 via the communication port 11, which includes an NM message containing sleep information SL, and obtains the NM message from the received Ethernet frame. The receiving unit 13 outputs the obtained NM message to the processing unit 14.

[0107] Upon receiving a sleep notification, the receiving unit 13 stops sending measurement information to the vehicle ECU 111C.

[0108] More specifically, the processing unit 14 receives an NM message from the receiving unit 13 and obtains sleep information SL from the received NM message. Based on the obtained sleep information SL, the processing unit 14 recognizes that the vehicle ECU 111C has entered a sleep state. Then, the processing unit 14 stops generating measurement information that should be sent to the vehicle ECU 111C.

[0109] For example, even after the receiving unit 13 receives the sleep notification, the sending unit 12 continues to broadcast the NM message.

[0110] Refer again Figure 3 After detecting that the vehicle ECU 111C has entered a dormant state, the detection unit 23 determines that the vehicle ECU 111C has entered an active state upon receiving an NM message from the vehicle ECU 111C. Then, the detection unit 23 notifies the NM sending unit 24 and the notification unit 25 of the activation determination information indicating that the vehicle ECU 111C has entered an active state.

[0111] When activation determination information is received from the detection unit 23, the NM transmission unit 24 begins to generate an Ethernet frame containing an NM message, which is sent to the vehicle ECU 111C as indicated by the received activation determination information.

[0112] Refer again Figure 4 The notification table Tb1 in the storage unit 26 also indicates the correspondence between groups of vehicle ECUs 111 belonging to different VLANs and whether or not an activation notification is needed to the vehicle ECUs 111 in the other group when one of the vehicle ECUs 111 in the group becomes active.

[0113] Refer again Figure 3 Upon receiving activation determination information from the detection unit 23 indicating that the vehicle ECU 111C has changed to an active state, the notification unit 25, referring to the notification table Tb1, decides to send an activation notification to the vehicle ECU 111A indicating that the vehicle ECU 111C has changed to an active state. Furthermore, the notification unit 25 outputs a notification instruction to the NM transmission unit 24 indicating that the vehicle ECU 111A should be notified that the vehicle ECU 111C has changed to an active state.

[0114] The NM sending unit 24 receives a notification instruction from the notification unit 25 and generates an NM message containing activation information AC indicating that the vehicle ECU 111C has changed to an active state. Then, the NM sending unit 24 generates an Ethernet frame containing the generated NM message and sends it to the vehicle ECU 111A via the relay unit 22 and the communication port 21.

[0115] Refer again Figure 2 The receiving unit 13 in the vehicle ECU 111A receives an Ethernet frame containing an NM message with activation information AC from the relay device 101 via the communication port 11, and obtains the NM message from the received Ethernet frame. The receiving unit 13 outputs the obtained NM message to the processing unit 14.

[0116] The processing unit 14 receives an NM message from the receiving unit 13 and obtains activation information AC from the received NM message. Based on the obtained activation information AC, the processing unit 14 recognizes that the vehicle ECU 111C has entered an active state. Then, the processing unit 14 begins to output periodic measurement information to the transmitting unit 12.

[0117] The transmitting unit 12 generates an Ethernet frame containing measurement information received from the processing unit 14, and transmits the generated Ethernet frame to the vehicle ECU 111C via the communication port 11 and the relay device 101.

[0118] [Action Flow]

[0119] Each device in the vehicle communication system according to the embodiments of this disclosure includes a computer containing a memory. The computer's CPU or other arithmetic processing unit reads from the memory and executes a program comprising some or all of the steps in the following sequence. The programs for these multiple devices can be installed externally. The programs for these multiple devices are either stored on a recording medium or transmitted via a communication line.

[0120] Figure 5 This is a flowchart illustrating an example of the operational steps of a relay device according to an embodiment of this disclosure when performing relay processing. (Refer to...) Figure 5 The relay device 101 first waits for Ethernet frames from the vehicle ECU 111 ("No" in step S102). When it receives an Ethernet frame from a vehicle ECU 111 ("Yes" in step S102), it relays the received Ethernet frame. For example, the relay device 101 receives an Ethernet frame containing measurement information from vehicle ECU 111A belonging to VLAN 10, and sends the received Ethernet frame to vehicle ECU 111C belonging to VLAN 20 (step S104).

[0121] Figure 6 This is a flowchart illustrating an example of the operational steps taken by a relay device according to an embodiment of this disclosure when issuing a sleep notification. (See also...) Figure 6 First, the relay device 101 waits for a change in the arrival status of the NM message from the vehicle ECU 111 ("No" in step S202). For example, if the arrival of the NM message from the vehicle ECU 111C stops ("Yes" in both step S202 and step S204), it determines that the vehicle ECU 111C has entered a sleep state. More specifically, for example, if the relay device 101 determines that the vehicle ECU 111C has entered a sleep state if the NM message from the vehicle ECU 111C has not arrived within a specified time and the latest NM message from the vehicle ECU 111C contains change information (step S206).

[0122] Next, the relay device 101 sends a sleep notification to the vehicle ECU 111A indicating that the vehicle ECU 111C has entered a sleep state. More specifically, it generates an NM message containing sleep information SL indicating that the vehicle ECU 111C has entered a sleep state, and sends an Ethernet frame containing the generated NM message to the vehicle ECU 111A (step S208).

[0123] Next, the relay device 101 waits for a new change in the status of the arrival of the NM message from the vehicle ECU 111. For example, if the arrival of the NM message from the vehicle ECU 111C restarts ("Yes" in step S202 and "No" in step S204), it determines that the vehicle ECU 111C has changed to an active state (step S210).

[0124] Next, the relay device 101 sends an activation notification to the vehicle ECU 111A indicating that the vehicle ECU 111C has changed to an active state. More specifically, it generates an NM message containing activation information AC indicating that the vehicle ECU 111C has changed to an active state, and sends an Ethernet frame containing the generated NM message to the vehicle ECU 111A (step S212).

[0125] Next, the relay device 101 waits for a new change in the status of the NM message from the vehicle ECU 111 (in step S202, it is "No").

[0126] Figure 7 This is a flowchart illustrating an example of the operational steps involved in determining the sending of information from an in-vehicle ECU to other in-vehicle ECUs according to an embodiment of this disclosure. Figure 7 This is a flowchart illustrating an example of the operational steps when the vehicle ECU 111A sends measurement information to the vehicle ECU 111C.

[0127] Reference Figure 7 First, the vehicle ECU 111A begins sending measurement information to the vehicle ECU 111C. Specifically, the vehicle ECU 111A periodically includes the measurement information in an Ethernet frame and sends it to the vehicle ECU 111C via the relay device 101 (step S302).

[0128] Next, the vehicle ECU 111A repeatedly sends measurement information to the vehicle ECU 111C periodically until it receives a sleep notification or activation notification from the relay device 101 (No in step S304).

[0129] Next, when the vehicle ECU 111A receives a sleep notification from the relay device 101, specifically when it receives an Ethernet frame from the relay device 101 that includes an NM message containing sleep information SL (yes in step S304 and yes in step S306), it recognizes that the vehicle ECU 111C has entered a sleep state and stops sending measurement information to the vehicle ECU 111C (step S308).

[0130] Next, the vehicle ECU 111A waits for a sleep notification or an activation notification ("No" in step S304). If it receives an activation notification from the relay device 101, specifically, if it receives an Ethernet frame from the relay device 101 that includes an NM message containing activation information AC ("Yes" in step S304 and "No" in step S306), it recognizes that the vehicle ECU 111C has changed to an active state and restarts sending measurement information to the vehicle ECU 111C (step S310).

[0131] Figure 8 This is a diagram illustrating an example of the communication sequence in a vehicle communication system according to an embodiment of the present disclosure. Figure 8 This indicates the communication sequence of relay device 101 and vehicle ECUs 111A and 111C.

[0132] Reference Figure 8 First, the vehicle ECU111A periodically broadcasts NM messages within VLAN10 (step S402).

[0133] In addition, the vehicle ECU111C periodically broadcasts NM messages within VLAN20 (step S404).

[0134] In addition, the relay device 101 periodically sends NM messages to the vehicle ECU 111A (step S406) and periodically sends NM messages to the vehicle ECU 111C (step S408).

[0135] In addition, the vehicle ECU 111A periodically sends Ethernet frames containing measurement information to the relay device 101 destined for the vehicle ECU 111C (step S410).

[0136] The relay device 101 relays the Ethernet frames received from the vehicle ECU 111A to the vehicle ECU 111C (step S412).

[0137] Next, the vehicle ECU 111C detects that the state of vehicle 1 meets the sleep conditions and broadcasts an NM message containing transition information (step S414).

[0138] Next, the vehicle ECU 111C transitions to sleep mode, stopping the periodic broadcasting of NM messages (step S416).

[0139] Next, the relay device 101 stops sending NM messages to the vehicle ECU 111C based on the arrival of the NM message from the vehicle ECU 111C and the latest NM message contains change information, and determines that the vehicle ECU 111C has entered a sleep state, and stops sending NM messages to the vehicle ECU 111C (step S418).

[0140] Next, the relay device 101 sends the hibernation information SL to the vehicle ECU 111A in an NM message (step S420).

[0141] Next, the vehicle ECU 111A receives an NM message containing sleep information SL from the relay device 101, recognizing that the vehicle ECU 111C has entered a sleep state. Then, the vehicle ECU 111A stops sending Ethernet frames containing measurement information to the vehicle ECU 111C (step S422).

[0142] Next, the vehicle ECU 111C detects that the state of vehicle 1 meets the wake-up conditions and transitions to the active state (step S424).

[0143] Next, the vehicle ECU 111C resumes the regular broadcasting of NM messages (step S426).

[0144] Next, the relay device 101 receives the NM message from the vehicle ECU 111C and determines that the vehicle ECU 111C has changed to an active state (step S428).

[0145] Next, the relay device 101 resumes sending NM messages to the vehicle ECU 111C (step S430).

[0146] Next, the relay device 101 includes the activation information AC in the NM message and sends it to the vehicle ECU 111A (step S432).

[0147] Next, the vehicle ECU 111A receives an NM message containing activation information AC from the relay device 101, recognizing that the vehicle ECU 111C has switched to an active state. Then, the vehicle ECU 111A resumes sending Ethernet frames containing measurement information to the vehicle ECU 111C (step S434).

[0148] The relay device 101 relays the Ethernet frames received from the vehicle ECU 111A to the vehicle ECU 111C (step S436).

[0149] Furthermore, in the vehicle communication system 301 according to the embodiments of this disclosure, the vehicle ECU 111A is a sensor, but is not limited to this. The vehicle ECU 111A may also be a vehicle device other than a sensor. Additionally, the vehicle ECU 111C is a driver assistance device, but is not limited to this. The vehicle ECU 111C may also be a vehicle device other than a driver assistance device.

[0150] Furthermore, in the relay device 101 according to the embodiments of this disclosure, the detection unit 23 is configured to determine that the vehicle ECU 111 has entered a sleep state if the NM message periodically broadcast by the vehicle ECU 111 within the VLAN to which the vehicle ECU 111 belongs does not arrive within a predetermined time, but this is not limited to this. For example, the detection unit 23 may also be configured to monitor the power supply status from a power source (not shown) installed in the vehicle 1 to the vehicle ECU 111, and determine that the vehicle ECU 111 has entered a sleep state based on the monitoring results. Specifically, the detection unit 23 determines that the vehicle ECU 111 has entered a sleep state if the amount of power supplied from the power source to the vehicle ECU 111 is less than a predetermined value.

[0151] Furthermore, in the relay device 101 according to the embodiments of this disclosure, the detection unit 23 is configured to determine whether the vehicle ECU 111 has entered a sleep state or has malfunctioned if the NM message from the vehicle ECU 111 does not arrive within a predetermined time, but it is not limited to this. The detection unit 23 may also be configured to not determine whether the vehicle ECU 111 has malfunctioned if the NM message from the vehicle ECU 111 does not arrive within the predetermined time, but instead determine that the vehicle ECU 111 has entered a sleep state.

[0152] Furthermore, in the relay device 101 according to the embodiments of this disclosure, the storage unit 26 is configured to store a notification table Tb1, which represents the correspondence between groups of vehicle ECUs 111 belonging to different VLANs and whether a sleep notification needs to be sent to another vehicle ECU 111 in the same group when one vehicle ECU 111 in the group enters a sleep state, but is not limited to this. The storage unit 26 may also be configured not to store the notification table Tb1. In this case, for example, when the detection unit 23 detects that a vehicle ECU 111 has entered a sleep state, the notification unit 25 sends a sleep notification to all vehicle ECUs 111 belonging to a VLAN different from the VLAN to which the vehicle ECU 111 belongs.

[0153] Furthermore, in the relay device 101 according to the embodiments of this disclosure, the notification unit 25 is configured to perform sleep notification by including information indicating that a certain vehicle ECU 111 has changed to a sleep state in an NM message sent by the NM transmission unit 24, but it is not limited to this. For example, the notification unit 25 may also be configured to perform sleep notification by separately generating an Ethernet frame containing sleep information SL and sending the generated Ethernet frame to the destination vehicle ECU 111 via the relay unit 22 and the communication port 21.

[0154] Furthermore, in the vehicle ECU 111 according to the embodiments of this disclosure, the transmitting unit 12 is configured to continue broadcasting NM messages even after the receiving unit 13 receives a sleep notification, but it is not limited to this. The transmitting unit 12 may also be configured to stop broadcasting NM messages when the receiving unit 13 receives a sleep notification, and restart broadcasting NM messages when the receiving unit 13 receives an activation notification.

[0155] However, there is a desire for techniques that can further reduce the traffic volume in vehicle communication systems. More specifically, in a vehicle communication system where vehicle ECU 111A periodically transmits Ethernet frames containing measurement information to vehicle ECU 111C, when vehicle ECU 111C enters a sleep state, the Ethernet frames sent from vehicle ECU 111A to vehicle ECU 111C are not received by vehicle ECU 111C. Therefore, to reduce the traffic volume in the vehicle communication system, it is preferable to stop the transmission of Ethernet frames from vehicle ECU 111A to vehicle ECU 111C during the period when vehicle ECU 111C is in a sleep state.

[0156] For example, if the vehicle ECU111A belongs to the same VLAN as the vehicle ECU111C, it can detect the transition of the vehicle ECU111C to a sleep state based on the arrival status of the NM message broadcast from the vehicle ECU111C, and stop sending Ethernet frames to the vehicle ECU111C.

[0157] However, when the vehicle ECU111A belongs to a different VLAN than the vehicle ECU111C, it is impossible to detect the transition of the vehicle ECU111C to a sleep state. Therefore, during the period when the vehicle ECU111C is in a sleep state, it is impossible to stop the transmission of Ethernet frames to the vehicle ECU111C.

[0158] In contrast, in the relay device 101 according to the embodiments of this disclosure, the relay unit 22 relays information between multiple vehicle ECUs 111 belonging to different VLANs. The detection unit 23 detects when the vehicle ECU 111C enters a sleep state. When the detection unit 23 detects that the vehicle ECU 111C has entered a sleep state, the notification unit 25 sends a sleep notification to the vehicle ECU 111A indicating that the vehicle ECU 111C has entered a sleep state.

[0159] In this way, by detecting the transition of the vehicle ECU 111C to a sleep state in the relay device 101 and sending a sleep notification to the vehicle ECU 111A, which belongs to a different VLAN than the vehicle ECU 111C, indicating that the vehicle ECU 111C has transitioned to a sleep state, the vehicle ECU 111A can recognize that the vehicle ECU 111C has transitioned to a sleep state. Therefore, for example, the transmission of information from the vehicle ECU 111A to the vehicle ECU 111C can be stopped during the period when the vehicle ECU 111C is in a sleep state. As a result, the communication volume in the vehicle communication system can be further reduced.

[0160] It should be considered that the above embodiments are illustrative in all respects and are not restrictive. The scope of the invention is shown not by the foregoing description but by the scope of the claims, and is intended to include all modifications within the scope and equivalent of the claims.

[0161] The above description includes the following features.

[0162] [Postscript 1]

[0163] A vehicle-mounted communication system includes a vehicle-mounted relay device and a first vehicle-mounted device and a second vehicle-mounted device belonging to different VLANs, wherein...

[0164] The vehicle-mounted relay device relays information between the first vehicle-mounted device and the second vehicle-mounted device.

[0165] The second vehicle-mounted device sends information to the first vehicle-mounted device via the vehicle-mounted relay device.

[0166] The vehicle-mounted relay device detects that the first vehicle-mounted device has switched to a sleep state and sends a sleep notification to the second vehicle-mounted device indicating that the first vehicle-mounted device has switched to a sleep state.

[0167] The second vehicle-mounted device receives the hibernation notification from the vehicle-mounted relay device and stops sending information to the second vehicle-mounted device.

[0168] Label Explanation

[0169] 1 vehicle

[0170] 2 cables

[0171] 11 communication ports

[0172] 12 Sending Department

[0173] 13 Receiving Department

[0174] 14 Processing Department

[0175] 15 Storage Department

[0176] 21 communication ports

[0177] 22 Relay Unit

[0178] 23 Testing Department

[0179] 24 NM Transmitter

[0180] 25 Notification Department

[0181] 26 Storage Department

[0182] 101 Relay Device

[0183] 111, 111A, 111B, 111C, 111D vehicle ECU

[0184] 301 Vehicle Communication System

[0185] Tb1 Notification Table.

Claims

1. A vehicle-mounted relay device, comprising: The relay unit relays information between multiple vehicle-mounted devices belonging to different VLANs (Virtual Local Area Networks). The detection unit detects that the on-board device has switched to a sleep state; and The notification unit, when the detection unit detects that the first vehicle-mounted device among the plurality of vehicle-mounted devices has entered a sleep state, sends a sleep notification to the second vehicle-mounted device among the plurality of vehicle-mounted devices, the sleep notification indicating that the first vehicle-mounted device has entered a sleep state.

2. The vehicle-mounted relay device according to claim 1, wherein, If the first NM message, i.e. the first network management message, which is periodically broadcast by the first vehicle device within the VLAN to which the first vehicle device belongs, does not arrive within a specified time, the detection unit determines that the first vehicle device has entered a dormant state, and the first NM message indicates that the first vehicle device is in an active state.

3. The vehicle-mounted relay device according to claim 2, wherein, If the first NM message does not arrive within the specified time, the detection unit determines whether the first vehicle-mounted device has switched to a sleep state or has malfunctioned.

4. The vehicle-mounted relay device according to any one of claims 1 to 3, wherein, The vehicle-mounted relay device also includes a storage unit that stores notification information. This notification information indicates the correspondence between groups of vehicle-mounted devices belonging to different VLANs and whether a hibernation notification needs to be sent to another vehicle-mounted device in the group if one of the vehicle-mounted devices in the group has entered a hibernation state.

5. The vehicle-mounted relay device according to any one of claims 1 to 4, wherein, The second vehicle-mounted device is a sensor. The first vehicle-mounted device is a driving assistance device that provides driving assistance based on the measurement results of the sensors.

6. The vehicle-mounted relay device according to any one of claims 1 to 5, wherein, The vehicle-mounted relay device also includes a transmitting unit that periodically sends a second NM message, i.e., a second network management message, to each vehicle-mounted device. The second NM message indicates that the vehicle-mounted relay device is in an active state. After the detection unit detects that the first vehicle-mounted device has switched to a sleep state, the transmitting unit also continues to send the second NM message to the second vehicle-mounted device. The notification unit sends the sleep notification to the second vehicle device by including information indicating that the first vehicle device has switched to a sleep state in the second NM message sent by the sending unit.

7. A vehicle-mounted device, wherein, The vehicle-mounted device includes: The transmitting unit sends information to other vehicle-mounted devices belonging to different VLANs via the vehicle-mounted relay device; and The receiving unit receives a sleep notification from the vehicle-mounted relay device indicating that the other vehicle-mounted devices have switched to sleep mode. Upon receiving the hibernation notification, the transmitting unit ceases sending information to the other vehicle-mounted devices.

8. The vehicle-mounted device according to claim 7, wherein, The transmitting unit periodically broadcasts NM messages indicating that the vehicle-mounted device is active within the VLAN to which the vehicle-mounted device belongs. The transmitting unit also continues to broadcast the NM message after the receiving unit receives the sleep notification.

9. A sleep notification method, comprising the following steps: Relaying of information between multiple vehicle-mounted devices belonging to different VLANs; The system detects that the first vehicle-mounted device among the plurality of vehicle-mounted devices has entered a dormant state; and A hibernation notification is sent to the second vehicle-mounted device among the plurality of vehicle-mounted devices, indicating that the first vehicle-mounted device has entered a hibernation state.

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