Vehicle-mounted optical communication link failure detection system, method, and vehicle

Abstract

The application discloses a kind of vehicle-mounted optical communication link fault detection system, method and vehicle, it is related to vehicle technical field.System includes: optical network unit;Passive optical brancher is connected with optical network unit, constitutes sublink, fiber array is etched with different center wavelength fiber Bragg grating, with each sublink one-to-one correspondence;First light splitter is connected with the optical network unit connected with passive optical brancher;Optical switch is connected with first light splitter;Fault diagnosis module is used to control optical switch full pass, obtain the optical time domain reflection trace of whole link, control optical switch each first light splitter is selected in turn, different identification wavelength probe light signal is sent to each sublink in turn, the reflection signal of fiber Bragg grating is received, to determine fault sublink, according to optical time domain reflection trace determines breakpoint position, generates detection result.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and in particular to a vehicle-mounted optical communication link fault detection system, method, and vehicle. Background Technology

[0002] With the development of intelligent and connected vehicles, the requirements for data transmission rate and stability of in-vehicle communication systems are becoming increasingly stringent. In-vehicle optical communication links, with their advantages of high bandwidth, low latency, and resistance to electromagnetic interference, have become the core carrier for in-vehicle Ethernet and autonomous driving perception data transmission. However, the compact and frequently vibrating environment of vehicles makes optical links prone to failures such as breakage and loose connectors.

[0003] To address this, related technologies have proposed calculating the fault distance by detecting the echo transmission time of light with a single wavelength, but this technology has low positioning accuracy. In particular, vehicle-mounted optical networks generally adopt a multi-branch topology combining star and tree structures, with dozens of optical network units densely deployed in areas such as the cockpit and doors. The distance between adjacent branch links is often less than 1 meter, making it impossible to distinguish the specific branch where the fault is located. Summary of the Invention

[0004] The purpose of this invention is to propose a vehicle-mounted optical communication link fault detection system, method, and vehicle to improve the fault location accuracy of vehicle-mounted optical communication links, reduce detection costs, and ensure the reliable operation of vehicle-mounted optical communication networks.

[0005] In a first aspect, embodiments of the present invention propose a vehicle-mounted optical communication link fault detection system. The detection system includes: m×n optical network units (ONUs) for connecting vehicle-mounted equipment, where n and m are integers greater than 0; n passive optical splitters, each having m output ports, each output port being connected one-to-one with each of the ONUs to form m×n sub-links; m fiber Bragg gratings with different center wavelengths etched on the fiber array of each passive optical splitter, each fiber Bragg grating corresponding one-to-one with each sub-link to provide wavelength identification for each sub-link; and n first optical splitters, each first optical splitter connected to one of the passive optical splitters. The connected m optical network units are respectively connected to: an optical switch, which is connected to n first optical splitters respectively; and a fault diagnosis module, which is connected to the optical switch, for controlling the optical switch to be fully open, obtaining the optical time-domain reflection trace of the entire link by scanning the optical reflection characteristics, and controlling the optical switch to select each first optical splitter one by one, sending probe optical signals of different identification wavelengths to each sub-link corresponding to the selected first optical splitter in sequence, receiving the reflection signal from the fiber Bragg grating, and determining the faulty sub-link based on the sub-link that did not receive the corresponding wavelength reflection signal, determining the breakpoint position based on the optical time-domain reflection trace, and generating a detection result containing the faulty sub-link identifier and the breakpoint position.

[0006] In some embodiments, the detection system further includes a central computing platform, which includes a system-on-a-chip (SoC) and n optical line terminals (OLTs). The SoC is connected to the fault diagnosis module and the n OLTs, respectively, and is used to send detection commands to the fault diagnosis module and send downlink electrical signals to each OLT. Each OLT is connected to a passive optical splitter (POP), and is used to receive the downlink electrical signals sent by the SoC and convert them into optical signals to be sent to the corresponding POP, so that the POP distributes the optical signals to the corresponding sub-links.

[0007] In some embodiments, the fault diagnosis module includes an optical time-domain reflectometer module, a wavelength analysis module, and a controller. The optical time-domain reflectometer module is used to acquire the optical time-domain reflection traces of each sub-link by scanning the optical reflection characteristics. The wavelength analysis module is used to sequentially send probe optical signals with different identifier wavelengths to each sub-link corresponding to the selected first beam splitter, receive the reflection signal from the fiber Bragg grating, and determine the faulty sub-link based on the sub-link that did not receive the corresponding wavelength reflection signal. The controller is connected to the optical time-domain reflectometer module, the wavelength analysis module, the optical switch, and the system-on-a-chip, respectively. When the detection command is received, the controller controls the optical switch to be fully open and controls the optical time-domain reflectometer module to start the optical time-domain reflection scan. When the existence of a faulty sub-link is determined based on the optical time-domain reflection traces, the controller controls the optical switch to select each first beam splitter one by one and controls the wavelength analysis module to start the wavelength analysis. The controller also determines the breakpoint location based on the optical time-domain reflection traces and generates a detection result containing the faulty sub-link identifier and the breakpoint location.

[0008] In some embodiments, the wavelength analysis module includes a tunable laser, a circulator, a demultiplexer, m photodetectors, and a processing unit: the tunable laser is used to sequentially send probe light signals of different identified wavelengths; the circulator is used to guide the probe light signals into sub-links and guide the reflected light signals to the demultiplexer; the demultiplexer is used to separate the reflected light signals of different wavelengths; each photodetector is used to convert the separated reflected light signals of the corresponding wavelength into electrical signals; the processing unit is used to collect and process the electrical signals, and determine the faulty sub-links based on the sub-links that have not received the reflected signals of the corresponding wavelengths.

[0009] In some embodiments, the fault diagnosis module further includes a second beam splitter; the second beam splitter is connected to the optical switch, the optical time domain reflectometer module, and the wavelength analysis module, respectively, and is used to distribute the reflected light signal from the optical switch to the optical time domain reflectometer module and the wavelength analysis module, and to combine the probe light signals from the optical time domain reflectometer module and the wavelength analysis module to the optical switch.

[0010] In some embodiments, the optical network unit includes a coupler, a single-fiber bidirectional optical transceiver assembly, a transmitting circuit, a receiving circuit, and a control chip. The coupler is connected to a corresponding first beam splitter and a sub-link to which the optical network unit is connected, respectively, for receiving probe optical signals from the first beam splitter into the sub-link and transmitting reflected optical signals from the sub-link to the first beam splitter. The single-fiber bidirectional optical transceiver assembly is connected to the coupler for realizing single-fiber bidirectional optical transmission and reception. The transmitting circuit is connected to the single-fiber bidirectional optical transceiver assembly for generating laser signals. The receiving circuit is connected to the single-fiber bidirectional optical transceiver assembly for receiving laser signals. The control chip is connected to the transmitting circuit, the receiving circuit, and a corresponding vehicle-mounted device, respectively, for controlling the transmitting circuit to generate laser signals, controlling the receiving circuit to process the received laser signals, and realizing data transmission between the optical network unit and the vehicle-mounted device.

[0011] Secondly, embodiments of the present invention propose a method for detecting faults in a vehicle-mounted optical communication link, applied to the vehicle-mounted optical communication link fault detection system described in the first aspect embodiment. The method includes the following steps: in response to a detection command, controlling the optical switch to be fully open, and obtaining the optical time-domain reflection trace of the entire link by scanning the optical reflection characteristics; in response to determining the existence of a faulty sub-link based on the optical time-domain reflection trace, controlling the optical switch to sequentially select each first beam splitter, and sequentially sending probe optical signals of different identification wavelengths to each sub-link corresponding to the selected first beam splitter; receiving the reflection signal from the fiber Bragg grating, and determining the faulty sub-link based on the sub-link that did not receive the corresponding wavelength reflection signal; determining the breakpoint location based on the optical time-domain reflection trace, and generating a detection result containing the faulty sub-link identifier and the breakpoint location.

[0012] In some embodiments, obtaining the optical temporal reflection trace of each sub-link by scanning the optical reflection characteristics includes: emitting an optical pulse within a preset wavelength range, wherein the preset wavelength range avoids the reflection wavelength of the fiber Bragg grating and the communication signal wavelength; receiving the reflected optical signal generated by the optical pulse in each sub-link, and generating an optical temporal reflection trace.

[0013] Thirdly, embodiments of the present invention provide a vehicle, including: the vehicle-mounted optical communication link fault detection system described in the first aspect embodiment.

[0014] In some embodiments, the vehicle further includes m×n on-board devices, each of which is connected to one of the m×n optical network units to form an optical fiber communication network.

[0015] This invention discloses a vehicle-mounted optical communication link fault detection system, method, and vehicle. The detection system includes: m×n optical network units (ONUs) for connecting vehicle-mounted equipment, where n and m are integers greater than 0; n passive optical splitters, each having m output ports, each output port being connected to an ONU to form m×n sub-links, and each ONU having m fiber Bragg gratings of different center wavelengths etched on its fiber array, each fiber Bragg grating corresponding to a sub-link to provide wavelength identification for each sub-link; and n first optical splitters, each first optical splitter being connected to one of the m ONUs connected to a ONU. An optical switch is connected to each of the n first optical splitters. A fault diagnosis module, connected to the optical switch, controls the optical switch to be fully open, acquires the optical time-domain reflection trace of the entire link through optical reflection characteristic scanning, and controls the optical switch to sequentially select each first optical splitter, sending probe optical signals of different identified wavelengths to each sub-link corresponding to the selected first optical splitter. It receives reflected signals from fiber Bragg gratings, identifies faulty sub-links based on sub-links that do not receive reflection signals of the corresponding wavelength, and determines the breakpoint location based on the optical time-domain reflection trace, generating a detection result containing the faulty sub-link identifier and the breakpoint location. Therefore, through a dual detection mechanism combining optical time-domain reflection scanning and wavelength identification analysis, the fault location accuracy of the vehicular optical communication link can be improved, detection costs reduced, and the reliable operation of the vehicular optical communication network ensured. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a vehicle-mounted optical communication link fault detection system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a vehicle-mounted optical communication link fault detection system according to another embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a wavelength analysis module according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of an optical network unit according to an embodiment of the present invention; Figure 5 This is a flowchart of the working process of a vehicle-mounted optical communication link fault detection system according to a specific embodiment of the present invention; Figure 6 This is a flowchart of a vehicle-mounted optical communication link fault detection method according to an embodiment of the present invention; Figure 7This is a structural block diagram of a vehicle according to an embodiment of the present invention. Detailed Implementation

[0017] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0018] The following description, with reference to the accompanying drawings, describes an embodiment of the vehicle-mounted optical communication link fault detection system, method, and vehicle of the present invention.

[0019] Figure 1 This is a schematic diagram of the structure of a vehicle-mounted optical communication link fault detection system according to an embodiment of the present invention.

[0020] like Figure 1 As shown, the vehicle-mounted optical communication link fault detection system 100 includes: m×n optical network units (ONUs) 10, n passive optical splitters 20, n first optical splitters 30, an optical switch 40, and a fault diagnosis module 50. Here, n and m are integers greater than 0, and their values ​​can be flexibly selected according to the scale of the vehicle-mounted optical network, the number of vehicle-mounted devices 200 to be connected, and the network topology. For example, m can be 8 or 16, and n can be 4, 8, or 16 to adapt to the communication node quantity requirements of different vehicle models.

[0021] See Figure 1 An m×n optical network unit 10 is used to connect to the vehicle-mounted equipment 200. The optical network unit 10 receives electrical signals from the corresponding vehicle-mounted equipment and converts them into optical signals for transmission to the passive optical splitter 20, and receives optical signals from the passive optical splitter 20 and converts them into electrical signals for transmission to the corresponding vehicle-mounted equipment, thereby achieving bidirectional conversion and data transmission between optical and electrical signals. The vehicle-mounted equipment includes, but is not limited to, autonomous driving perception sensors, vehicle-mounted cameras, millimeter-wave radar, lidar, in-vehicle entertainment terminals, and vehicle control modules. Each vehicle-mounted device connects to the vehicle-mounted optical communication network through its corresponding optical network unit 10 to achieve reliable data transmission.

[0022] Each passive optical splitter 20 can be a 1×m planar lightwave circuit (PLC) type optical splitter with m output ports. Each output port is connected to each optical network unit 10 in a one-to-one correspondence, forming m×n sub-links. Each passive optical splitter 20 has m fiber Bragg gratings (FBGs) with different center wavelengths etched at its fiber array (FA) in a wavelength-coded manner. Each FBG corresponds one-to-one with each sub-link, providing a unique wavelength identifier for each sub-link. When a probe optical signal passes through this optical splitter, these FBGs will specifically reflect their designated wavelengths, thereby assigning a unique identifier to each of the m sub-PON links. This design allows each sub-link to have unique wavelength characteristics. This wavelength coding mechanism not only solves the problem that traditional PLC splitters cannot distinguish downstream links, but also provides a key basis for fault diagnosis: when the optical network unit 10 or the vehicle-mounted equipment 200 fails, the optical splitter port where the fault point is located can be quickly located by analyzing the reflected wavelength characteristics, which greatly improves the efficiency of fault location.

[0023] Each first optical splitter 30 is connected to m optical network units 10 connected to a passive optical splitter 20, forming a convergence point for the detection signals. The optical switch 40 can be a 1×n mechanical or micro-electro-mechanical system (MEMS) type optical switch, with one input port and n output ports, connected to n first optical splitters 30 respectively, used to switch detection channels under the control of the fault diagnosis module 50. The fault diagnosis module 50 is connected to the optical switch 40 and serves as the detection core of the detection system. It controls the optical switch 40 to be fully open, obtains the optical time-domain reflection trace of the entire link through optical reflection characteristic scanning, and controls the optical switch 40 to select each first optical splitter one by one, sequentially sending probe optical signals of different identification wavelengths to each sub-link corresponding to the selected first optical splitter 30, receiving reflection signals from fiber Bragg gratings, identifying faulty sub-links based on sub-links that do not receive reflection signals of the corresponding wavelength, determining the breakpoint location based on the optical time-domain reflection trace, and generating a detection result containing the faulty sub-link identifier and breakpoint location.

[0024] Specifically, the fault diagnosis module 50 employs a dual detection mechanism combining optical time-domain reflectometry (OTDR) scanning and wavelength identification analysis. First, the fault diagnosis module 50 controls the optical switch 40 to be fully open, acquiring the optical time-domain reflectometry trace of the entire link through optical reflectometry scanning. This trace reflects the overall health status of the fiber optic link, including breakpoint location and loss anomalies. When a fault is detected, the fault diagnosis module 50 further controls the optical switch 40 to sequentially select each of the first optical splitters 30, sending probe optical signals with different identification wavelengths to each sub-link corresponding to the selected first optical splitter 30. These probe optical signals correspond to the center wavelength of the FBG of each sub-link.

[0025] When the probe optical signal reaches the FBG at the end of the sub-link, if the link is normal, the FBG will reflect the optical signal of the corresponding wavelength; if the link is broken, the reflected signal of that wavelength will not return. The fault diagnosis module 50 receives the reflected signal from the FBG and can accurately determine the faulty sub-link based on the sub-link that did not receive the reflected signal of the corresponding wavelength. At the same time, the fault diagnosis module 50 determines the breakpoint location based on the previously acquired optical temporal reflection trace, and finally generates a complete detection result containing the faulty sub-link identifier and the breakpoint location.

[0026] This embodiment uses a passive optical splitter 20 with etched FBG (First-Fast Generation) to provide a unique wavelength identifier for each sub-link. Combined with the dual detection mechanism of the fault diagnosis module 50, it can further accurately locate the faulty sub-link after detecting the fault through optical time-domain reflectometry. Even if the distance between adjacent branch links is less than 1 meter, it can accurately distinguish them, achieving precise location of faults in the vehicle-mounted optical communication link, thereby ensuring the reliable operation of the vehicle-mounted optical communication network. Furthermore, the entire process does not require blindly increasing the number of detection wavelengths to distinguish links, which can reduce device costs.

[0027] In some embodiments of the present invention, such as Figure 2 As shown, the detection system 100 also includes a central computing platform 60, which includes a system on chip (SOC) 61 and n optical line terminals (OLTs) 62.

[0028] See Figure 2 The system-on-chip 61 is connected to the fault diagnosis module 50 and n optical line terminals 62, respectively, and is used to send detection commands to the fault diagnosis module 50 and send downlink electrical signals to each optical line terminal 62. Each optical line terminal 62 is connected to a passive optical splitter 20, and is used to receive the downlink electrical signals sent by the system-on-chip 61, convert them into optical signals and send them to the corresponding passive optical splitter 20, so that the passive optical splitter 20 can distribute the optical signals to the corresponding sub-links.

[0029] Specifically, the System-on-Chip 61, acting as the intelligent hub of the entire vehicle-mounted optical communication network, is responsible for the unified scheduling and management of multiple sub-Passive Optical Networks (PONs), coordinating data exchange between the OLT and ONUs, and ensuring efficient data flow between the vehicle-mounted devices 200. The Optical Line Terminal 62, serving as the interface between the optical network and the electrical network, converts electrical signals to optical signals, providing stable optical signal input for each sub-link.

[0030] Specifically, the SOC transmits downlink data to the ONU and vehicle-mounted equipment via the OLT, while simultaneously receiving uplink information from the ONU. Furthermore, the SOC integrates the functions of a fault detection module, continuously monitoring network communication status, identifying anomalies in real time, and handling them accordingly. When the vehicle communication system detects an anomaly in an actuator or network node through the protocol layer, the system-on-chip 61 sends a detection command to the fault diagnosis module 50.

[0031] This embodiment achieves centralized control and management of fault detection and normal communication by setting up a central computing platform 60. The system-on-a-chip (SoC) 61, acting as the intelligent hub, coordinates the work of the fault diagnosis module 50 and the optical line terminal 62. During normal communication, the SoC 61 sends downlink data to each sub-link through the optical line terminal 62. When detection is required, the SoC 61 sends a detection command to the fault diagnosis module 50, initiating a dual detection mechanism. This architecture allows fault detection and normal communication to be both independent and collaborative. The detection process does not affect normal data transmission, and the SoC 61 can obtain detection results in real time, facilitating timely countermeasures and improving the system's intelligence and response efficiency.

[0032] In some embodiments, see Figure 1 , Figure 2 The fault diagnosis module 50 includes an optical time-domain reflectometer (OTDR) module 51, a wavelength analysis module 52, and a controller 53.

[0033] The optical time-domain reflectometer module 51 is used to acquire the optical time-domain reflection traces of each sub-link through optical reflection characteristic scanning. The wavelength analysis module 52 is used to sequentially send probe optical signals with different identification wavelengths to each sub-link corresponding to the selected first beam splitter 30, receive the reflection signals from the fiber Bragg grating, and determine the faulty sub-link based on the sub-link that did not receive the corresponding wavelength reflection signal. The controller 53 is connected to the optical time-domain reflectometer module 51, the wavelength analysis module 52, the optical switch 40, and the system-on-a-chip 61, respectively. When a detection command is received, it controls the optical switch 40 to be fully open and controls the optical time-domain reflectometer module 51 to start the optical time-domain reflection scan. When a faulty sub-link is determined based on the optical time-domain reflection trace, it controls the optical switch 40 to select each first beam splitter 30 one by one and controls the wavelength analysis module 52 to start the wavelength analysis. Each PON is scanned one by one, and the breakpoint location is determined based on the optical time-domain reflection trace, generating a detection result containing the faulty sub-link identifier and the breakpoint location.

[0034] Specifically, the optical time-domain reflectometer module 51 emits optical pulses within a preset wavelength range. This preset wavelength range avoids the reflection wavelengths of fiber Bragg gratings (FBGs) and communication signal wavelengths to prevent interference with the identification of normal communication signals and FBG reflection signals. It also receives reflected optical signals generated in each sub-link, generating a clear and accurate link reflection characteristic curve (i.e., an optical time-domain reflection trace) reflecting the health status of the fiber optic link. The controller 53 determines whether a fault exists based on this optical time-domain reflection trace. If a fault exists, it triggers the wavelength analysis module 52 for precise location. The wavelength analysis module 52 sequentially sends a probe optical signal with a corresponding identification wavelength to each sub-link, one-to-one with the center wavelength of its FBG. When a sub-link experiences an open circuit, its corresponding probe optical signal cannot be reflected back through the FBG, and the wavelength analysis module 52 can then determine that the sub-link is faulty. As the control core of the fault diagnosis module 50, the controller 53 can determine the location of the fault point (i.e., the breakpoint location) by combining the position of the reflection peak of the OTDR trace after determining that a fault has occurred in a certain sub-link. In this way, by coordinating the working timing of the optical time domain reflectometer module 51 and the wavelength analysis module 52, the dual detection mechanism of "coarse inspection first and fine inspection" is realized. After all PONs have completed scanning, the detection results are fed back to the central computing platform.

[0035] This embodiment constructs a complete dual detection mechanism by setting up an optical time-domain reflectometer module 51, a wavelength analysis module 52, and a controller 53. The optical time-domain reflectometer module 51, acting as the first line of defense, can quickly scan the entire link and initially determine the location of the breakpoint. The wavelength analysis module 52, acting as the second line of defense, accurately locates the faulty sub-link by using FBG wavelength marking after detecting it. The controller 53 coordinates the working sequence of the two modules to ensure the orderly progress of the detection process. This mechanism overcomes the technical deficiency of related technologies that cannot distinguish specific faulty sub-links in multi-branch topologies, accurately distinguishing them even when the distance between adjacent branch links is less than 1 meter.

[0036] For example, see Figure 1 , Figure 2 The fault diagnosis module 50 also includes a second beam splitter 54. The second beam splitter 54 is connected to the optical switch 40, the optical time domain reflectometer module 51, and the wavelength analysis module 52, respectively, and is used to distribute the reflected light signal from the optical switch 40 to the optical time domain reflectometer module 51 and the wavelength analysis module 52, and to combine the probe light signals from the optical time domain reflectometer module 51 and the wavelength analysis module 52 to the optical switch 40.

[0037] By setting up a second beam splitter 54, the optical time-domain reflectometer module 51 and the wavelength analysis module 52 share the same port of the optical switch 40, reducing the number of channels in the optical switch 40, simplifying the system hardware structure, and lowering cost and system complexity. Simultaneously, the second beam splitter 54 has both splitting and combining functions, capable of simultaneously distributing the reflected light signal to both modules and combining the detection light signals from both modules to the optical switch 40, achieving efficient transmission of the detection signal.

[0038] In some embodiments, such as Figure 3 As shown, the wavelength analysis module 52 includes a tunable laser 521, a circulator 522, a dewavelength division multiplexer 523, m photodetectors 524, and a processing unit 525.

[0039] The system includes a tunable laser 521 that sequentially transmits probe light signals of different wavelengths; a circulator 522 that guides the probe light signals into the sub-link and directs the reflected light signals to a demultiplexer 523; the demultiplexer 523 that separates the reflected light signals of different wavelengths; and a photodetector 524 that converts the separated reflected light signals of the corresponding wavelength into electrical signals. A processing unit 525 collects and processes the electrical signals, identifying faulty sub-links based on which no reflected signal of the corresponding wavelength has been received.

[0040] Specifically, the tunable laser 521 has the capability for precise step-tuning within a preset wavelength range, and can sequentially output m pulsed lasers with different center wavelengths according to a predetermined sequence or control commands. Each wavelength corresponds to the FBG identification wavelength of a sub-link to be detected. This step-transmission characteristic allows the tunable laser 521 to orderly excite the FBGs at the ends of each sub-link to generate reflected signals, facilitating subsequent signal separation and analysis. The circulator 522, acting as an optical path guide, constructs a unidirectional optical path: the probe light signal emitted by the tunable laser 521 enters the optical link through the circulator 522, while the light signal reflected back from the FBG enters the de-wavelength division multiplexer 523 in a specific direction, ensuring the correct transmission of the optical signal within the wavelength analysis module 52. Since the tunable laser 521 sequentially sends probe light signals of different wavelengths, and these light signals are reflected back by the FBG, the demultiplexer 523 is responsible for physically or logically separating these reflected light signals with different wavelengths, so that the system can process the probe signal corresponding to each wavelength in sequence, thereby realizing independent analysis of multiple sub-links.

[0041] The photodetector 524 can be a photodiode, capable of converting the received weak reflected light signal into a corresponding analog electrical signal for subsequent signal processing and analysis. The processing unit 525 acquires the electrical signal output from the photodetector 524 at high speed and digitizes it. Based on the received reflected signal wavelength information and the known mapping relationship between FBG wavelengths and sub-links, it determines whether there are wavelengths for which no reflected signal is received. If the reflected signal of a certain identified wavelength is not present, the sub-link corresponding to that wavelength is determined to be a faulty sub-link.

[0042] This embodiment constructs a complete wavelength analysis module 52 using a tunable laser 521, a circulator 522, a dewavelength division multiplexer 523, m photodetectors 524, and a processing unit 525 to achieve precise location of faulty sub-links. The tunable laser 521 performs step-by-step tuning scanning of each sub-link to avoid signal crosstalk; the circulator 522 effectively separates the probe light from the reflected light, improving the signal-to-noise ratio; the dewavelength division multiplexer 523 separates reflected light of different wavelengths, ensuring independent processing of each channel; the m photodetectors 524 detect m sub-links in parallel, improving efficiency; and the processing unit 525 accurately identifies faulty sub-links through digital acquisition and wavelength mapping analysis. This module works in conjunction with the optical time-domain reflectometer module 51. After detecting a fault through optical time-domain reflectometry scanning, it accurately locates the faulty sub-link using wavelength identification technology, even if the distance between adjacent branch links is less than 1 meter. This overcomes the shortcomings of related technologies that cannot distinguish specific faulty branches and eliminates the need to blindly increase the number of probe wavelengths, effectively reducing device costs.

[0043] For example, the processing unit 525 may employ a Field Programmable Gate Array (FPGA). The FPGA, acting as the brain of the wavelength analysis module, is the core logic for signal control, data acquisition, wavelength analysis, and result judgment. It possesses advantages such as strong parallel processing capabilities, fast response speed, and flexible programmable configuration. It can acquire the electrical signals output by the photodetector 524 at high speed, perform real-time digital processing, and, based on the received reflected signal wavelength information and the known mapping relationship between the FBG wavelength and the link, determine whether a faulty link exists.

[0044] Specifically, the FPGA integrates a high-speed analog-to-digital converter interface, a digital signal processing unit, and wavelength mapping logic. Through a parallel processing architecture, it simultaneously samples the output signals of m photodetectors 524. Based on a preset wavelength-to-sub-link mapping table, it quickly determines whether the reflected signal of each identified wavelength appears, thereby accurately identifying the faulty sub-link. The FPGA's programmability also supports flexible configuration of wavelength mapping relationships according to the optical network topology of different vehicle models, without modifying the hardware circuitry, thus improving the system's versatility and scalability.

[0045] In some embodiments, such as Figure 4 As shown, the optical network unit 10 includes a coupler 11, a single-fiber bidirectional optical sub-assembly (BOSA) 12, a transmitting circuit 13, a receiving circuit 14, and a control chip 15.

[0046] Coupler 11 is connected to the corresponding sub-links of the first beam splitter 30 and the optical network unit 10, respectively, for receiving the probe light signal from the first beam splitter 30 into the sub-link and transmitting the reflected light signal from the sub-link to the first beam splitter 30. A single-fiber bidirectional optical transceiver assembly 12 is connected to coupler 11 to achieve single-fiber bidirectional optical transmission and reception. Transmitting circuit 13 is connected to single-fiber bidirectional optical transceiver assembly 12 to generate laser signals; receiving circuit 14 is connected to single-fiber bidirectional optical transceiver assembly 12 to receive laser signals. Control chip 15 is connected to transmitting circuit 13, receiving circuit 14, and the corresponding vehicle-mounted device 200, respectively, for controlling transmitting circuit 13 to generate laser signals, controlling receiving circuit 14 to process received laser signals, and realizing data transmission between optical network unit 10 and vehicle-mounted device 200.

[0047] Specifically, coupler 11 can be a 1×2 fiber optic coupler with one input port and two output ports. The input port is connected to the first optical splitter 30, the first output port is connected to the sub-link, and the second output port is connected to the single-fiber bidirectional optical transceiver assembly 12. Coupler 11 is mainly used to effectively converge the uplink detection signal from the first optical splitter 30 and realize dynamic connection with the link through optical switch 40, thereby supporting diagnostic operations. As the intersection node of detection signal and communication signal, coupler 11 enables the probe light of fault diagnosis module 50 to smoothly enter the sub-link for detection, while ensuring that the reflected light signal can return to fault diagnosis module 50. Normal communication signal is transmitted through single-fiber bidirectional optical transceiver assembly 12, realizing effective separation of detection and communication.

[0048] The single-fiber bidirectional optical transceiver assembly 12 integrates transmission and reception functions, enabling simultaneous transmission and reception of optical signals on the same optical fiber. It uses different wavelengths of light for uplink and downlink transmission respectively, thus saving fiber optic resources and reducing cabling complexity. Under the control of the control chip 15, the transmitting circuit 13 converts the electrical signal from the vehicle-mounted device 200 into an optical signal of the corresponding wavelength, which is then transmitted to the sub-link via the single-fiber bidirectional optical transceiver assembly 12. The receiving circuit 14 converts the optical signal received by the single-fiber bidirectional optical transceiver assembly 12 into an electrical signal and transmits it to the control chip 15 for processing. The control chip 15, as the control core of the optical network unit 10, is responsible for communication protocol processing, status management, and data interaction, ensuring that the vehicle-mounted device 200 can reliably access the vehicle-mounted optical communication network.

[0049] This embodiment constructs an optical network unit 10 using a coupler 11, a single-fiber bidirectional optical transceiver assembly 12, a transmitting circuit 13, a receiving circuit 14, and a control chip 15. The coupler 11 separates the detection signal from the communication signal, ensuring that fault detection and normal communication do not interfere with each other. The single-fiber bidirectional optical transceiver assembly 12 employs single-fiber bidirectional technology, requiring only one optical fiber for simultaneous signal transmission and reception, saving fiber resources compared to a dual-fiber solution and making it suitable for compact vehicle environments. The transmitting circuit 13 and receiving circuit 14 have clearly defined functions, respectively responsible for transmitting and receiving optical signals, improving processing efficiency. The control chip 15 manages transmission, reception, and data transmission in a unified manner, achieving intelligent control. This optical network unit 10 works in conjunction with the fault diagnosis module 50, ensuring reliable data transmission during normal operation, and providing a dedicated channel for the detection light during fault detection, ensuring the detection signal smoothly enters the sub-link. This design, together with the dual detection mechanism, constitutes a complete system, guaranteeing both communication reliability and accurate fault location.

[0050] The following is combined with Figure 5 Taking m=8 as an example, the description is as follows: Figure 2 The workflow of the vehicle-mounted optical communication link fault detection system 100 in the illustrated embodiment is as follows. Figure 5 As shown, the fault detection process for vehicle-mounted optical communication links includes: S1, when the SOC detects an anomaly in the optical communication link, it sends a detection command to the controller.

[0051] S2, the controller controls the OTDR module to emit a probe light signal with wavelength λ0.

[0052] The detection light signal at wavelength λ0 is a pulse signal within a specified range that avoids the critical wavelength.

[0053] S3, the controller controls the optical switch to be in the fully on state.

[0054] At this point, all input optical signals will be evenly distributed to N output ports, or all optical signals from the output ports will be converged to the input ports.

[0055] S4, the probe optical signal is transmitted to each fiber sub-link via a passive splitter, and the reflected optical signal returns along the original path and is received by the OTDR module to obtain the link reflection characteristic curve.

[0056] The link reflection characteristic curve is the optical time-domain reflection trace, which reflects the link status.

[0057] S5, the controller determines whether there is an abnormal reflection peak in the link reflection characteristic curve.

[0058] If an abnormal reflection peak appears, it may indicate a break in the link, proceed to the next step; otherwise, jump to S15.

[0059] S6 indicates that a fiber optic cable has been broken in the optical network link system.

[0060] S7, turn on the 1×n optical switch channels one by one, and adjust the wavelength analysis module to perform link analysis.

[0061] Each channel of the optical switch is connected to 8 links by an optical splitter. In the wavelength analysis module, a tunable laser emits optical signals with wavelengths of λ1 to λ8, which enter the link through a circulator. Some wavelengths are specifically reflected by the FBG and then received by a photodetector after passing through a demultiplexer. The FPGA analyzes the characteristics of the reflected signal.

[0062] S8, determine λ x Does the corresponding wavelength signal appear? If it appears, proceed to the next step; otherwise, jump to S12.

[0063] S9, Determine the channel wavelength λ x The corresponding sub-link is normal.

[0064] S10, Determine whether the optical switch has completed scanning of the 8 wavelengths of this channel. If the scan is not completed, proceed to S8 to check the next wavelength and ensure that all 8 links in the channel are in normal condition; otherwise, proceed to the next step.

[0065] S11, Determine whether the scan of the n channels of the optical switch is complete? If the scan is not completed, proceed to S7 to continue to the next channel corresponding to the link for detection; otherwise, proceed to S14.

[0066] S12, Determine the channel wavelength λ x The corresponding link is broken.

[0067] S13, combined with the link reflection characteristic curve, record the breakpoint location and link information.

[0068] Proceed to step S10.

[0069] S14, Return link fault information The link failure information is the detection result mentioned above.

[0070] S15 returns link health information.

[0071] S16, end the link fault detection process.

[0072] The vehicle-mounted optical communication link fault detection system of this invention can achieve the following technical effects: 1) Utilizing the dual detection principle of OTDR rapid screening + wavelength analysis for precise fault location, the OTDR enables rapid preliminary fault location; the passive optical splitter grating markers are used to perform wavelength analysis on the echo signal, accurately pinpointing the link segment and specific location of the fault, enabling the differentiation of faults in adjacent links, and meeting the needs of fault location in compact vehicle spaces. 2) The ONU-side uplink detection design is adopted, and the detection optical signal is transmitted from the ONU-side to the uplink. This reduces the dynamic range requirement, avoids the terminal reflection signal being overwhelmed by noise due to excessive transmission, improves the terminal signal recognition capability, reduces the dynamic range requirement, and solves the problem of missed detection of terminal faults. 3) Integrating a fiber Bragg grating inside the passive optical splitter, this identifier is integrated with the passive optical splitter. By leveraging the inherent structure of the passive optical splitter to integrate the identifier, stable identification of link segments can be achieved without adding additional identifier equipment or modifying the system, thus meeting the integration requirements of "lightweight and miniaturized" in vehicles.

[0073] Figure 6 This is a flowchart of a vehicle-mounted optical communication link fault detection method according to an embodiment of the present invention. This vehicle-mounted optical communication link fault detection method is applied to the vehicle-mounted optical communication link fault detection system 100 described in the above embodiment.

[0074] like Figure 6As shown, the method for detecting faults in vehicle-mounted optical communication links includes the following steps: S61, in response to the detection command, controls the optical switch to be fully open and obtains the optical temporal reflection trace of the entire link by scanning the optical reflection characteristics.

[0075] S62, in response to determining the existence of a faulty sub-link based on the optical time-domain reflection trace, controls the optical switch to select each first beam splitter one by one, and sequentially sends probe optical signals of different identification wavelengths to each sub-link corresponding to the selected first beam splitter.

[0076] S63 receives the reflected signal from the fiber Bragg grating and determines the faulty sub-link based on the sub-link that did not receive the reflected signal of the corresponding wavelength.

[0077] S64 determines the breakpoint location based on the optical temporal reflection trace and generates a detection result containing the faulty sub-link identifier and the breakpoint location.

[0078] In some embodiments, the optical temporal reflection trace of each sub-link is obtained by scanning the optical reflection characteristics, including: emitting an optical pulse within a preset wavelength range, wherein the preset wavelength range avoids the reflection wavelength of the fiber Bragg grating and the communication signal wavelength; receiving the reflected optical signal generated by the optical pulse in each sub-link, and generating an optical temporal reflection trace.

[0079] It should be noted that other specific implementations of the vehicle-mounted optical communication link fault detection method of the present invention can be found in the specific implementation of the vehicle-mounted optical communication link fault detection system 100 in the above embodiments.

[0080] Figure 7 This is a structural block diagram of a vehicle according to an embodiment of the present invention.

[0081] like Figure 7 As shown, the vehicle 1000 includes the vehicle-mounted optical communication link fault detection system 100 of the above embodiment.

[0082] For example, the vehicle also includes m×n on-board devices 200 ( Figure 7 As shown in the figure, m×n vehicle-mounted devices 200 are connected one-to-one with m×n optical network units 10 to form an optical fiber communication network.

[0083] Specifically, the vehicle-mounted equipment 200 includes, but is not limited to: autonomous driving perception sensors (such as lidar, millimeter-wave radar, and ultrasonic radar), vehicle-mounted cameras (such as front-view cameras and surround-view cameras), vehicle-mounted entertainment terminals (central control screen and rear-seat entertainment screen), vehicle control modules (door control, window control, and seat adjustment), navigation and positioning modules, and V2X communication modules. Each vehicle-mounted device 200 connects to the vehicle-mounted optical communication network through its corresponding optical network unit 10, enabling high-speed data interaction with the central computing platform 60.

[0084] When the vehicle 1000 is operating normally, the system-on-chip 61 sends control commands and data to each optical network unit 10 through the optical line terminal 62 and the passive optical splitter 20. Each on-board device 200 uploads the collected sensing data and status information to the system-on-chip 61 for processing and decision-making through the optical network unit 10. When the on-board optical communication link fails, the fault diagnosis module 50 activates a dual detection mechanism: first, it quickly obtains the optical time-domain reflection trace of the entire link through optical time-domain reflection scanning to initially determine the breakpoint location; then, the wavelength analysis module 52 sequentially sends probe light signals with different identification wavelengths to each sub-link, accurately locating the faulty sub-link based on the sub-link that did not receive the corresponding wavelength reflection signal; finally, it generates a detection result containing the faulty sub-link identification and breakpoint location for maintenance personnel to quickly repair.

[0085] The vehicle-mounted optical communication link fault detection system 100 is deeply integrated with the vehicle 1000, fully leveraging the advantages of high bandwidth, low latency, and electromagnetic interference resistance of fiber optic communication to ensure reliable transmission of autonomous driving perception data, in-vehicle entertainment information, and vehicle control commands. Simultaneously, through a dual detection mechanism, it achieves rapid detection and precise location of vehicle-mounted optical communication link faults, effectively avoiding serious consequences such as autonomous driving decision errors and in-vehicle entertainment system malfunctions caused by communication link failures, significantly improving vehicle safety and reliability.

[0086] In summary, the vehicle-mounted optical communication link fault detection system, method, and vehicle of this invention, taking into account the dynamic, compact, and multi-point connection characteristics of the vehicle environment, can quickly diagnose fiber optic link faults, significantly improving detection efficiency, positioning accuracy, and system reliability. Specifically: 1) Rapid link status detection using OTDR, combined with wavelength analysis technology for precise fault location. The OTDR acquires reflected signals from the fiber optic link in real time, analyzes the time delay and intensity characteristics of the reflection peaks to preliminarily determine the breakpoint location. Simultaneously, a tunable laser emits probe pulses corresponding one-to-one with the center wavelength of each sub-link's fiber optic cable (FBG), and fault verification is performed based on the wavelength information of the reflected signals. This dual detection mechanism achieves rapid fault response and high-precision fault location in complex vehicular optical network environments, significantly reducing the false alarm rate and ensuring the stable operation of the vehicular communication system.

[0087] 2) By adopting an ONU-side uplink detection mode, the detection point is moved from the traditional OLT end to the ONU end, effectively avoiding the problem of the reflected signal at the end being submerged by noise due to excessive transmission distance. When performing uplink detection at the ONU end, the signal-to-noise ratio is enhanced by modulating the wavelength parameters of the reflected signal, thereby improving the reliability of fault detection. This design is particularly suitable for link fluctuation problems that occur during vehicle operation, improving the overall system response speed and real-time performance.

[0088] 3) By integrating fiber Bragg gratings as link identifiers into the PLC optical splitter, the system's environmental stability and integration are improved. Compared to traditional stand-alone reflectors, the integrated grating in the PLC optical splitter offers higher mechanical stability and temperature adaptability, enabling it to withstand frequent vibrations and temperature changes in the vehicle environment. Simultaneously, this design significantly simplifies the system structure, supporting one OLT connecting m ONU nodes through a 1×m splitter, reducing system complexity and hardware costs.

[0089] Therefore, this invention provides a low-cost, simple-architecture, and accurate vehicle optical network link detection system and method, providing reliable technical support for large-scale optical network deployment in vehicles.

[0090] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0091] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0092] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0093] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0094] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A vehicle-mounted optical communication link fault detection system, characterized in that, The detection system includes: m×n optical network units are used to connect vehicle-mounted equipment, where n and m are integers greater than 0; There are n passive optical splitters, each of which has m output ports. Each output port is connected to each optical network unit in a one-to-one correspondence to form m×n sub-links. Each passive optical splitter has m fiber Bragg gratings with different center wavelengths etched on its fiber array. Each fiber Bragg grating corresponds to each sub-link and is used to provide wavelength identification for each sub-link. n first optical splitters, each of which is connected to m optical network units connected to one of the passive optical splitters; Optical switches are connected to n of the first beam splitters, respectively; The fault diagnosis module, connected to the optical switch, is used to control the optical switch to be fully open, obtain the optical temporal reflection trace of the entire link by scanning the optical reflection characteristics, and control the optical switch to select each first beam splitter one by one, sending probe optical signals of different identification wavelengths to each sub-link corresponding to the selected first beam splitter in sequence, receiving the reflection signal from the fiber Bragg grating, and determining the faulty sub-link based on the sub-link that did not receive the corresponding wavelength reflection signal, determining the breakpoint location based on the optical temporal reflection trace, and generating a detection result containing the faulty sub-link identifier and the breakpoint location.

2. The vehicle-mounted optical communication link fault detection system according to claim 1, characterized in that, The detection system also includes a central computing platform, which includes a system-on-a-chip and n optical line terminals; The system-on-a-chip is connected to the fault diagnosis module and n optical line terminals respectively, and is used to send detection commands to the fault diagnosis module and send downlink electrical signals to each of the optical line terminals. Each optical line terminal is connected to a passive optical splitter to receive downlink electrical signals from the system-on-chip and convert them into optical signals to be sent to the corresponding passive optical splitter, so that the passive optical splitter can distribute the optical signals to the corresponding sub-links.

3. The vehicle-mounted optical communication link fault detection system according to claim 2, characterized in that, The fault diagnosis module includes an optical time domain reflectometer module, a wavelength analysis module, and a controller; The optical time-domain reflectometer module is used to obtain the optical time-domain reflection traces of each sub-link by scanning the optical reflection characteristics; The wavelength analysis module is used to sequentially send probe light signals with different identification wavelengths to each sub-link corresponding to the first selected optical splitter, receive the reflected signal from the fiber Bragg grating, and determine the faulty sub-link based on the sub-link that did not receive the corresponding wavelength reflected signal. The controller is connected to the optical time-domain reflectometer module, the wavelength analysis module, the optical switch, and the system-on-a-chip, respectively. When the detection command is received, the controller controls the optical switch to be fully open and controls the optical time-domain reflectometer module to start optical time-domain reflectometry scanning. When a faulty sub-link is determined based on the optical time-domain reflectometry trace, the controller controls the optical switch to select each first beam splitter one by one and controls the wavelength analysis module to start wavelength analysis. The controller also determines the breakpoint location based on the optical time-domain reflectometry trace and generates a detection result containing the faulty sub-link identifier and the breakpoint location.

4. The vehicle-mounted optical communication link fault detection system according to claim 3, characterized in that, The wavelength analysis module includes a tunable laser, a circulator, a demultiplexer, m photodetectors, and a processing unit. The tunable laser is used to sequentially send probe light signals with different identification wavelengths; The circulator is used to guide the probe optical signal into the sub-link and guide the reflected optical signal to the dewavelength division multiplexer; The wavelength division multiplexer is used to separate reflected light signals of different wavelengths; Each photodetector is used to convert the separated reflected light signals of the corresponding wavelength into electrical signals; The processing unit is used to collect and process the electrical signal, and to determine the faulty sub-link based on the sub-link that has not received a reflection signal of the corresponding wavelength.

5. The vehicle-mounted optical communication link fault detection system according to claim 3 or 4, characterized in that, The fault diagnosis module also includes a second beam splitter; The second beam splitter is connected to the optical switch, the optical time-domain reflectometer module, and the wavelength analysis module, respectively, and is used to distribute the reflected light signal from the optical switch to the optical time-domain reflectometer module and the wavelength analysis module, and to combine the probe light signals from the optical time-domain reflectometer module and the wavelength analysis module to the optical switch.

6. The vehicle-mounted optical communication link fault detection system according to claim 1, characterized in that, The optical network unit includes a coupler, a single-fiber bidirectional optical transceiver assembly, a transmitting circuit, a receiving circuit, and a control chip; The coupler is connected to the corresponding first beam splitter and the sub-link connected to the optical network unit, respectively, and is used to input the probe optical signal from the first beam splitter into the sub-link and transmit the reflected optical signal from the sub-link to the first beam splitter. The single-fiber bidirectional optical transceiver assembly is connected to the coupler and is used to realize single-fiber bidirectional optical transceiver. The transmitting circuit is connected to the single-fiber bidirectional optical transceiver assembly and is used to generate laser signals; The receiving circuit is connected to the single-fiber bidirectional optical transceiver assembly and is used to receive laser signals; The control chip is connected to the transmitting circuit, the receiving circuit, and the corresponding vehicle-mounted equipment, respectively, and is used to control the transmitting circuit to generate laser signals, control the receiving circuit to process the received laser signals, and realize data transmission between the optical network unit and the vehicle-mounted equipment.

7. A method for detecting faults in a vehicle-mounted optical communication link, characterized in that, The method, applied to the vehicle-mounted optical communication link fault detection system according to any one of claims 1 to 6, comprises the following steps: In response to a detection command, the optical switch is controlled to be fully open, and the optical temporal reflection trace of the entire link is obtained by scanning the optical reflection characteristics. In response to determining the presence of a faulty sub-link based on the optical temporal reflection trace, the optical switch is controlled to select each first beam splitter one by one, and probe optical signals with different identification wavelengths are sent sequentially to each sub-link corresponding to the selected first beam splitter. The system receives reflected signals from the fiber Bragg grating and identifies faulty sub-links based on sub-links that do not receive reflected signals of the corresponding wavelength. The breakpoint location is determined based on the optical temporal reflection trace, and a detection result containing the faulty sub-link identifier and the breakpoint location is generated.

8. The method for detecting faults in a vehicle-mounted optical communication link according to claim 7, characterized in that, The step of obtaining the optical temporal reflection traces of each sub-link through scanning of optical reflection characteristics includes: The light pulse is emitted within a preset wavelength range, which avoids the reflection wavelength of the fiber Bragg grating and the wavelength of the communication signal. The reflected light signals generated by the optical pulse in each sub-link are received, and optical temporal reflection traces are generated.

9. A vehicle, characterized in that, include: The vehicle-mounted optical communication link fault detection system as described in any one of claims 1 to 6.

10. The vehicle according to claim 9, characterized in that, The vehicle also includes m×n on-board devices, each of which is connected to one of the m×n optical network units to form an optical fiber communication network.

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