A bidirectional MIPI D-PHY camera signal transmission system and method based on active optical fiber

Abstract

This invention discloses a bidirectional MIPI D-PHY camera signal transmission system and method based on active optical fiber, including a transmitting module connected to a camera; a receiving module connected to a host; and an optical fiber link for realizing bidirectional optical signal transmission over a single fiber. Both the transmitting and receiving modules include bidirectional optical sub-components, which integrate uplink optical transmitting components and downlink optical receiving components, achieving full-duplex transmission of video and control signals on the same optical fiber through wavelength division multiplexing. This invention integrates a serializer / deserializer chip and a bidirectional optical sub-component at both the transmitting and receiving ends, achieving fully isolated full-duplex transmission at the physical layer through wavelength division multiplexing filters. The serializer chip performs real-time adaptation and level conversion from the MIPI D-PHY protocol to serial signals, and the bidirectional optical sub-component integrates a transmitting laser and a photodetector, achieving wavelength isolation through thin-film filters.

Description

Technical Field

[0001] This invention relates to a bidirectional signal transmission system and method for MIPI D-PHY cameras based on active optical fiber. Background Technology

[0002] MIPI D-PHY, as one of the most widely used MIPI interface standards, is widely used for connecting cameras and display devices, including mobile phones, automotive systems, wearable devices, and Internet of Things (IoT) devices.

[0003] The newly launched MIPI D-PHY v3.0 solution in 2025 has achieved a transmission rate of 9Gbps ​​through a multi-channel architecture (see the MIPI D-PHY v3.0 Specification released by MIPI Alliance). This solution has been integrated into multiple mass-produced ADAS platforms and can effectively support low-latency transmission of video data from multiple high-definition cameras, providing a solid guarantee for real-time environmental perception and decision-making of autonomous vehicles and androids.

[0004] Because MIPI D-PHY is designed for short-distance transmission between chips within mobile devices, it features low power consumption and low drive current, making it unsuitable for long-distance (≥50cm) video signal transmission. Taking a forward-facing camera widely used in ADAS as an example, the D-PHY signal is typically encoded and level-converted using a SerDes chipset, becoming an A-PHY signal suitable for long-distance transmission. This A-PHY signal is then transmitted over long distances (≤15m) via a more interference-resistant coaxial cable. The transmission technology typically involves a serializer chip converting the camera's parallel D-PHY signal into a serial A-PHY signal, which is then transmitted via a coaxial cable to the receiving end's de-serializer chip, where it is restored to a D-PHY signal. This solution supports bidirectional synchronous communication, allowing the host to send synchronization signals, configuration commands, trigger commands, and other control information to the camera via a coaxial cable, enabling remote control of the camera, parameter adjustment, and multi-camera synchronization.

[0005] Currently, fiber optic transmission technology has been applied in some automotive Ethernet scenarios (such as multi-gigabit automotive optical Ethernet defined by IEEE 802.3cz), but these solutions are mainly geared towards Ethernet protocols and are not designed for direct fiber optic transmission of MIPI D-PHY signals, and cannot be directly compatible with the existing MIPI D-PHY camera ecosystem.

[0006] Although existing coaxial cable solutions support bidirectional communication between video signals and control, the demand for MIPI D-PHY bandwidth is surging as cameras evolve towards 4K / 8K (6Gbps / 12Gbps) and high dynamic range. Traditional coaxial solutions will struggle to meet the high real-time and high bandwidth requirements of future multi-sensor fusion, potentially leading to the following insurmountable technical bottlenecks in practical applications:

[0007] (1) Limited transmission distance: Due to the high-frequency attenuation of MIPI D-PHY electrical signals, the effective transmission distance of high-speed signals of a single coaxial cable is usually limited to 15m, which is difficult to meet the long-distance wiring requirements of large vehicles (such as trucks and rail transit). Table 1 shows a comparison of typical maximum cable length and attenuation.

[0008]

[0009] Table 1

[0010] The attenuation values ​​in the table are all nominal typical values; the maximum transmission length is calculated based on the link budget of the GMSL protocol under high temperature aging conditions of 105℃, and the actual performance may vary slightly depending on the specific cable batch and connection air loss.

[0011] (2) Weak anti-interference ability: Copper cables are easily affected by electromagnetic noise from motors, high-voltage wire harnesses, etc., which can cause video signal frame loss or bit errors.

[0012] (3) Relay dependency increases complexity: Repeaters are required for lengths exceeding 15m, which increases system complexity and signal delay (typical delay ≥ 1ms).

[0013] (4) High weight and cost of wire harness: Multiple cable segments need to be cascaded, copper material is used in large quantities, and the total system cost is higher than that of the fiber optic solution.

[0014] (5) Long-distance bidirectional communication performance degradation: The reverse channel and the forward channel of the coaxial scheme share the same physical medium. Due to return loss and near-end crosstalk, the available bandwidth of the reverse control channel drops sharply (≤100Mbps) after 5m, making it difficult to support real-time configuration and firmware upgrades. Summary of the Invention

[0015] The purpose of this invention is to provide a technical solution for a bidirectional transmission system and method for MIPI D-PHY camera signals based on active optical fiber, addressing the shortcomings of existing technologies. This invention integrates a serializer / deserializer chip and a bidirectional optical sub-component in both the transmitting and receiving modules. Full-duplex transmission with complete physical layer isolation is achieved through 1310nm / 1550nm wavelength division multiplexing filters. The serializer chip performs real-time adaptation and level conversion from the MIPI D-PHY protocol to serial signals. The bidirectional optical sub-component integrates both a transmitting laser and a photodetector, and wavelength isolation is achieved through thin-film filters.

[0016] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0017] A bidirectional MIPI D-PHY camera signal transmission system based on active optical fiber, characterized by comprising:

[0018] The transmitter module is connected to the camera. The transmitter module contains a serializer chip, which is used to receive and process MIPID-PHY video signals, perform parallel-to-serial conversion and signal level adaptation through the serializer chip, and convert them into optical signals for transmission. At the same time, it receives and processes downlink optical signals from optical fiber and restores them into control signals for the camera.

[0019] The receiver module is connected to the host. The receiver module contains a deserializer chip, which is used to receive and process the uplink optical signal from the optical fiber. The deserializer chip performs clock data recovery and serial-to-parallel conversion to restore the MIPI D-PHY video signal and provide it to the host. At the same time, it receives and processes the control signals from the host and converts them into optical signals for transmission.

[0020] And an optical fiber link, whose two ends are connected to the transmitting module and the receiving module respectively, to realize single-fiber bidirectional optical signal transmission;

[0021] Both the transmitting and receiving modules include a bidirectional optical sub-component, which integrates an uplink optical transmitting component and a downlink optical receiving component. Through wavelength division multiplexing, it enables full-duplex transmission of video signals and control signals on the same optical fiber.

[0022] This invention integrates a serializer / deserializer chip and a bidirectional optical sub-component in both the transmitting and receiving modules. It achieves full-duplex transmission with complete physical layer isolation through 1310nm / 1550nm wavelength division multiplexing filters. The serializer chip performs real-time adaptation and level conversion from the MIPI D-PHY protocol to the serial signal. The bidirectional optical sub-component integrates both a transmitting laser and a photodetector, and wavelength isolation is achieved through a thin-film filter.

[0023] Furthermore, the bidirectional optical sub-assembly includes:

[0024] A single tube shell;

[0025] A laser emitter, housed inside the tube, is used to generate an uplink optical signal of the first wavelength;

[0026] A photodetector, installed inside the tube housing, is used to receive the downlink optical signal of the second wavelength;

[0027] A filter is placed in the optical path between the laser transmitter, the photodetector and the fiber optic interface to allow the uplink optical signal of the first wavelength to pass through the optical fiber and to reflect the downlink optical signal of the second wavelength from the optical fiber to the photodetector, thereby realizing the separation and synthesis of optical signals.

[0028] Furthermore, the filter is a thin-film filter.

[0029] Furthermore, the optical fiber link is a single-mode fiber, with the first wavelength uplink optical signal using a wavelength of 1310nm and the second wavelength downlink optical signal using a wavelength of 1550nm, and the isolation between the two wavelengths is ≥40dB.

[0030] Furthermore, the MIPI D-PHY interface of the serializer chip is connected to the output of the camera to convert the parallel MIPI D-PHY video signal into a serial electrical signal and drive the laser emitter in the bidirectional optical sub-assembly.

[0031] Furthermore, the serializer chip also integrates a first reverse control channel interface, which is used to receive the downlink control signal converted by the downlink optical receiving component from the bidirectional optical sub-component and forward it to the camera.

[0032] Furthermore, the input terminal of the deserializer chip is connected to the output terminal of the photodetector of the bidirectional optical sub-assembly, which is used to perform clock data recovery and serial-to-parallel conversion on the received serial electrical signal, and restore it to a parallel MIPI D-PHY video signal for output to the host.

[0033] Furthermore, the deserializer chip also integrates a second reverse control channel interface, which is used to receive downlink control signals from the host and drive the laser emitter in the bidirectional optical sub-assembly.

[0034] Furthermore, the bidirectional optical sub-assembly is packaged in a TO-56 package and operates in a temperature range of -40°C to 105°C.

[0035] Furthermore, it also includes a CAN bus compatible module, which includes:

[0036] A CAN transceiver is used to convert CAN bus differential signals into TTL / CMOS levels.

[0037] The MCU, connected to the CAN transceiver, is used to convert TTL / CMOS levels into I2C or SPI signals to access the control interface of the serializer or deserializer chip, thereby controlling the camera.

[0038] Furthermore, it also includes at least one fiber optic switch node for receiving N fiber optic signals, converting the optical signals into electrical signals, processing them, converting them back into optical signals, and then sending them to the host via fiber optic signals. Each fiber optic cable is connected to a bidirectional optical sub-component at both ends. The fiber optic switch nodes are interconnected to achieve star topology cascaded transmission of multiple cameras, where N≥2.

[0039] A method for bidirectional transmission of MIPI D-PHY camera signals based on active optical fiber, applied to the transmission system described above, is characterized by comprising the following steps:

[0040] The forward transmission step, used to transmit the camera's MIPI D-PHY video signal to the host, includes:

[0041] The S1.1 camera input serializer chip performs parallel-to-serial conversion and embeds synchronization codes to generate a serial data stream;

[0042] The S1.2 serial data stream drives the laser transmitter of the first wavelength, generating an uplink modulated optical signal and coupling it into the optical fiber;

[0043] The filter inside the bidirectional optical sub-assembly of the S1.3 receiver module transmits the first wavelength optical signal from the optical fiber to the photodetector, where it is converted into an electrical signal.

[0044] The S1.4 electrical signal is amplified by a transimpedance amplifier and a limiting amplifier, and then input to the deserializer chip for clock data recovery and serial-to-parallel conversion, restoring it to a MIPI D-PHY video signal for output to the host.

[0045] The reverse transmission step, used to transmit control signals from the host to the camera, includes:

[0046] S2.1 The host's control signal is input to the deserializer chip's control interface to generate a drive signal;

[0047] The S2.2 drive signal drives the second wavelength laser emitter to generate a downlink modulated optical signal, which is then coupled into the optical fiber.

[0048] The filter inside the bidirectional optical sub-assembly of the S2.3 transmitter module reflects the second wavelength optical signal from the optical fiber to the photodetector, where it is converted into an electrical signal.

[0049] The S2.4 electrical signal is input to the control interface of the serializer chip, and then forwarded by the serializer chip to the camera, where it is converted back into a control signal.

[0050] Furthermore, it also includes a two-way synchronization step, specifically including:

[0051] The S3.1 uplink video stream uses a constant bit rate continuous transmission mode, while the downlink control stream uses a burst transmission mode. The two are completely isolated at the physical layer through wavelength division multiplexing.

[0052] S3.2 Set a FIFO buffer with a depth of ≥512 bytes at the receiving end module or the host end to absorb delay jitter on the transmission path;

[0053] S3.3 embeds timestamp information in video frames, and the receiving module or host end restores the frame synchronization relationship based on the timestamp information.

[0054] The present invention, by adopting the above-described technical solution, has the following beneficial effects:

[0055] 1. Real-time adaptation of MIPI D-PHY protocol and fiber optic transmission is achieved through serializer / deserializer chips, increasing the forward video transmission distance from 5m in coaxial solution to over 50m, while increasing the reverse control channel bandwidth from ≤100Mbps to 1Gbps, meeting the multi-camera interconnection requirements of L3 and above autonomous driving systems.

[0056] 2. By using 1310nm / 1550nm wavelength division multiplexing and thin-film filters, the physical layer of the forward video stream and the reverse control stream is completely isolated, eliminating the channel contention problem of the time division multiplexing scheme. The one-way transmission delay of the control signal is ≤10μs at a distance of 50m.

[0057] 3. A single active optical fiber replaces multiple cascaded coaxial cables, simplifying the system topology and reducing cable weight by approximately 60%; the fiber optic medium bit error rate is ≤10. -12 It is completely immune to electromagnetic interference.

[0058] 4. The bidirectional optical sub-assembly adopts a TO-56 package and has an operating temperature range of -40℃ to 105℃, meeting the reliability requirements of the automotive environment; the CAN bus compatible module enables seamless integration with existing automotive networks. Attached Figure Description

[0059] The present invention will be further described below with reference to the accompanying drawings:

[0060] Figure 1 This is a schematic diagram of the bidirectional transmission system in the MIPI D-PHY camera signal bidirectional transmission system and method based on active optical fiber of the present invention.

[0061] Figure 2This is a schematic diagram of the bidirectional optical sub-assembly in this invention.

[0062] Wherein: 1-Laser emitter; 2-Photodetector; 3-Base; 4-Tube shell; 5-Adapter; 6-Isolator; 7-Filter. Detailed Implementation

[0063] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0064] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0065] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0066] like Figure 1 As shown, this invention provides a bidirectional MIPI D-PHY camera signal transmission system based on active optical fiber, comprising a transmitter module, a receiver module, an optical fiber link, and a CAN bus compatible module.

[0067] The transmitter module is connected to the camera. The transmitter module contains a serializer chip, which is used to receive and process MIPI D-PHY video signals. The serializer chip performs parallel-to-serial conversion and signal level adaptation, and converts the signals into optical signals for transmission. At the same time, it receives and processes downlink optical signals from optical fiber, and restores them as control signals to provide to the camera.

[0068] The serializer chip's MIPI D-PHY interface is connected to the camera's output to convert parallel MIPI D-PHY video signals into serial electrical signals and drive the laser emitter in the bidirectional optical sub-assembly.

[0069] The serializer chip also integrates a first reverse control channel interface, which is used to receive downlink control signals converted by the downlink optical receiving component from the bidirectional optical sub-component and forward them to the camera.

[0070] The receiver module is connected to the host. The receiver module contains a deserializer chip, which is used to receive and process the uplink optical signal from the optical fiber. The deserializer chip performs clock data recovery and serial-to-parallel conversion to restore the MIPI D-PHY video signal and provide it to the host. At the same time, it receives and processes the control signals from the host and converts them into optical signals for transmission.

[0071] The input of the deserializer chip is connected to the output of the photodetector of the bidirectional optical sub-assembly. It is used to recover the clock data and convert the serial electrical signal received into a parallel MIPI D-PHY video signal and output it to the host.

[0072] The deserializer chip also integrates a second reverse control channel interface, which is used to receive downlink control signals from the host and drive the laser emitter in the bidirectional optical sub-assembly.

[0073] The serializer and deserializer chips use high-speed SerDes chips. The high-speed serial output of the SerDes chip is electrically matched and integrated with the BOSA active optical fiber to realize the bidirectional optical fiber transmission of MIPI D-PHY signals.

[0074] The serializer chip uses a high-speed SerDes chip that supports the MIPI D-PHY input interface and has the following functions: supports 4-channel MIPI D-PHY signal input, with a maximum channel rate of 2.5Gbps; built-in clock data recovery (CDR) circuit; supports RAW data pass-through and optional pixel-level compression (such as the compression format defined by the MIPI CSI-2 specification) to adapt to different bandwidth requirements; outputs differential signals to drive the BOSA laser emitter.

[0075] The deserializer chip, paired with the serializer chip, has the following functions: receiving differential electrical signals converted from photoelectric signals by BOSA; built-in equalizer and CDR circuitry to compensate for transmission loss; outputting 4-channel differential signals conforming to the MIPI D-PHY signal standard; and supporting I2C / SPI control interfaces for parameter configuration. The serializer interface with the MIPI D-PHY uses the standard D-PHY protocol, supporting HS (High Speed) and LP (Low Power) mode switching; the deserializer output also follows the D-PHY timing specification, ensuring seamless integration with downstream image processing chips.

[0076] The two ends of the optical fiber link are connected to the transmitting module and the receiving module, respectively, to realize bidirectional optical signal transmission on a single fiber.

[0077] The fiber optic link uses G652 standard single-mode fiber with a core diameter of 9μm, supporting coarse wavelength division multiplexing (CWDM). The first wavelength uplink optical signal, i.e., the uplink video data channel, uses a wavelength of 1310nm, and the second wavelength downlink optical signal, i.e., the downlink control data channel, uses a wavelength of 1550nm. The two wavelengths are spaced 240nm apart, and bidirectional separation with an isolation of ≥40dB can be achieved through a standard thin-film filter. The operating wavelength of the single-mode fiber is matched with the wavelength of the bidirectional optical sub-assemblies, and the transmission distance can reach 100m.

[0078] Both the transmitting and receiving modules include a Bi-directional Optical Sub-Assembly (BOSA), a single-fiber bi-directional optical device using COB (Chip On Board) packaging technology. The BOSA integrates an uplink optical transmitter and a downlink optical receiver, achieving full-duplex transmission of video and control signals on the same optical fiber via wavelength division multiplexing.

[0079] The reliability level of the bidirectional optical sub-assembly meets the AEC-Q100 / Q102 automotive-grade certification requirements, with an operating temperature range of -40℃ to 105℃. Its reliability in high-temperature, low-temperature, humid, and salt-spray environments meets the requirements of harsh working conditions such as rail transit, high-speed rail, and special vehicles.

[0080] like Figure 2 As shown, the bidirectional optical sub-assembly includes: a housing, a base, a laser emitter, a photodetector, an adapter, an isolator, and a filter.

[0081] The laser emitter is housed inside the tube and is used to generate an uplink optical signal of the first wavelength.

[0082] The photodetector is installed inside the tube housing to receive the downlink optical signal of the second wavelength;

[0083] The filter is placed in the optical path between the laser transmitter, the photodetector and the optical fiber interface. It is used to allow the uplink optical signal of the first wavelength to pass through the optical fiber and to reflect the downlink optical signal of the second wavelength from the optical fiber to the photodetector, thereby realizing the separation and synthesis of optical signals.

[0084] The filter is a thin-film filter.

[0085] The 1310nm FP-LD (Fabry-Perot laser diode) or DFB-LD (distributed feedback laser diode) is used for uplink video data transmission, and the 1550nm PIN photodiode is used for downlink control data reception. Wavelength division multiplexing is achieved through a thin-film filter (TFF) on the inner wall, which has high transmittance (≥95%) for the 1310nm wavelength and high reflectivity (≥99%) for the 1550nm wavelength.

[0086] The bidirectional optical sub-assembly is packaged in a TO-56 package and operates in a temperature range of -40°C to 105°C, meeting automotive-grade AEC-Q102 reliability requirements.

[0087] CAN bus compatible modules include:

[0088] A CAN transceiver is used to convert CAN bus differential signals into TTL / CMOS levels.

[0089] The MCU, connected to the CAN transceiver, is used to convert TTL / CMOS levels into I2C or SPI signals to access the control interface of the serializer or deserializer chip, thereby controlling the camera.

[0090] It also includes at least one fiber optic switch node, which receives N fiber optic signals, converts the optical signals into electrical signals, processes them, converts them back into optical signals, and then sends them to the host via fiber optic signals. Each fiber optic cable is connected to a bidirectional optical sub-component at both ends. The fiber optic switch nodes are interconnected to realize star topology cascaded transmission of multiple cameras, where N≥2.

[0091] This invention integrates a serializer / deserializer chip and a bidirectional optical sub-component in both the transmitting and receiving modules. It achieves full-duplex transmission with complete physical layer isolation through a 1310nm / 1550nm wavelength division multiplexing filter. The serializer chip performs real-time adaptation and level conversion from the MIPI D-PHY protocol to the serial signal. The bidirectional optical sub-component integrates both a transmitting laser and a photodetector, with wavelength isolation achieved through a thin-film filter. This invention overcomes the bottleneck of existing MIPI D-PHY signals being unable to achieve effective bidirectional transmission over distances exceeding 15m.

[0092] This invention achieves 50m ultra-long distance transmission, 1Gbps reverse control channel bandwidth, and full-duplex communication with complete physical layer isolation within the MIPI D-PHY protocol framework. This enables multi-camera systems to adopt a single-fiber bidirectional transmission architecture, simplifying cable layout, reducing failure risks, and improving system reliability, providing key infrastructure for multi-sensor fusion applications in autonomous driving / ADAS.

[0093] A method for bidirectional transmission of MIPI D-PHY camera signals based on active optical fiber, applied to the transmission system described above, includes the following steps: s

[0094] The forward transmission step (camera to host) is used to transmit the camera's MIPI D-PHY video signal to the host, including:

[0095] The MIPI D-PHY video signal (including 4 data channels and 1 clock channel) from the S1.1 camera is input to the serializer chip, where it is converted from parallel to serial and a synchronization code (Start of Frame (SOF), Start of Line (SOL), etc.) is embedded to generate a serial data stream.

[0096] The first wavelength laser transmitter inside the bidirectional optical sub-component of the S1.2 transmitter module receives the drive of the serial data stream, generates an uplink modulated optical signal, and couples it into the G652 single-mode fiber.

[0097] The filter inside the bidirectional optical sub-assembly of the S1.3 receiver module transmits the first wavelength optical signal from the optical fiber to the photodetector, where it is converted into an electrical signal.

[0098] The S1.4 electrical signal is amplified by a transimpedance amplifier (TIA) and a limiting amplifier (LA) and then input to a deserializer chip for clock data recovery (CDR) and serial-to-parallel conversion, restoring it to a MIPI D-PHY video signal for output to the host.

[0099] The reverse transmission step (host to camera) is used to transmit control signals from the host to the camera, including:

[0100] The S2.1 host's control commands (configuration commands, trigger commands, etc.) are input through the I2C / SPI control interface of the deserializer chip to generate drive signals;

[0101] The S2.2 drive signal drives the second wavelength laser emitter to generate a downlink modulated optical signal, which is then coupled into the optical fiber.

[0102] The filter inside the bidirectional optical sub-assembly of the S2.3 transmitter module reflects the second wavelength optical signal from the optical fiber to the photodetector, where it is converted into an electrical signal.

[0103] The S2.4 electrical signal is input to the control interface of the serializer chip, and then forwarded by the serializer chip to the camera, where it is converted back into a control signal.

[0104] In this process, the first and second wavelengths are used to achieve full-duplex transmission of bidirectional signals in a single optical fiber through wavelength division multiplexing.

[0105] It also includes a two-way synchronization step, specifically including:

[0106] The uplink video stream uses a constant bit rate (CBR) continuous transmission mode, while the downlink control stream uses a burst transmission mode. The two are completely isolated at the physical layer through wavelength division multiplexing, and there is no time division conflict.

[0107] Set up a FIFO buffer with a depth of ≥512 bytes on the receiving module or the host side to absorb delay jitter on the transmission path.

[0108] Timestamp information is embedded in video frames. The receiving module or host end restores the frame synchronization relationship based on the timestamp information, and the end-to-end transmission delay is controlled within 10μs (50m fiber optic distance).

[0109] Application Scenario 1: Multi-camera access for intelligent driving domain controllers. In L3 / L4 level autonomous driving systems, vehicles require 8-12 high-definition cameras (forward-looking, surround-view, rear-looking, etc.). In traditional solutions, each camera requires an independent coaxial cable to connect to the domain controller, resulting in a wiring harness weight of 3-5 kg, high cost, and complex wiring. This invention, while ensuring reliability, utilizes the low-loss characteristics of optical fiber to avoid the need for repeaters (saving repeater module costs) and simplifies the system topology (reducing wiring and debugging costs), resulting in an overall cost reduction compared to traditional multi-cascade solutions. The system supports full-duplex communication, allowing the domain controller to adjust camera parameters (exposure, gain, etc.) in real time via the downlink channel, with a response latency of <10μs, meeting the real-time requirements of ADAS.

[0110] Application Scenario 2: Expansion of In-Vehicle Ethernet Backbone Network. In the central computing platform architecture of new energy vehicles, sensor data from area controllers (such as doors, seats, and air conditioners) distributed throughout the vehicle needs to be aggregated to the central computing unit. Traditional in-vehicle Ethernet (such as 100BASE-T1) suffers severe signal attenuation at distances exceeding 15m, requiring the addition of repeaters. This invention utilizes the low-loss characteristics of optical fiber to achieve full-duplex communication of 3-6Gbps uplink video transmission and 1Gbps downlink control transmission within a 50m distance, eliminating the need for repeaters and simplifying the network topology. Simultaneously, optical fiber possesses electromagnetic interference resistance, making it suitable for harsh electromagnetic environments near high-voltage electric drive systems, thus improving system reliability.

[0111] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to achieve substantially the same technical effect are all covered within the protection scope of the present invention.

Claims

1. An active fiber based MIPI D-PHY camera signal bidirectional transmission system, characterized in that include: The transmitting module is connected to the camera. The transmitting module includes a serializer chip for receiving and processing MIPID-PHY video signals. The serializer chip performs parallel-to-serial conversion and signal level adaptation, and converts the signals into optical signals for transmission. At the same time, it receives and processes downlink optical signals from optical fibers and restores them to control signals for the camera. The receiver module is connected to the host. The receiver module includes a deserializer chip for receiving and processing uplink optical signals from the optical fiber. The deserializer chip performs clock data recovery and serial-to-parallel conversion to restore the MIPI D-PHY video signal and provide it to the host. At the same time, it receives and processes control signals from the host and converts them into optical signals for transmission. And an optical fiber link, the two ends of which are respectively connected to the transmitting end module and the receiving end module, for realizing single-fiber bidirectional optical signal transmission; Both the transmitting module and the receiving module include a bidirectional optical sub-component, which integrates an uplink optical transmitting component and a downlink optical receiving component, and realizes full-duplex transmission of video signals and control signals on the same optical fiber through wavelength division multiplexing. 2.The active fiber-based MIPI D-PHY camera signal bidirectional transmission system according to claim 1, wherein: The bidirectional optical sub-assembly includes: A single tube shell; A laser emitter is disposed inside the tube housing and is used to generate an uplink optical signal of a first wavelength; A photodetector is disposed inside the tube housing for receiving a downlink optical signal of the second wavelength; A filter is disposed in the optical path between the laser emitter, the photodetector and the optical fiber interface, for allowing the uplink optical signal of the first wavelength to pass through the optical fiber and for reflecting the downlink optical signal of the second wavelength from the optical fiber to the photodetector, thereby realizing the separation and synthesis of optical signals.

3. The MIPI D-PHY camera signal bidirectional transmission system based on active optical fiber according to claim 2, characterized in that: The filter is a thin-film filter.

4. The MIPI D-PHY camera signal bidirectional transmission system based on active optical fiber according to claim 2, characterized in that: The optical fiber link is a single-mode optical fiber. The uplink optical signal of the first wavelength uses a wavelength of 1310nm, and the downlink optical signal of the second wavelength uses a wavelength of 1550nm. The isolation between the two wavelengths is ≥40dB.

5. The MIPI D-PHY camera signal bidirectional transmission system based on active optical fiber according to claim 2, characterized in that: The MIPI D-PHY interface of the serializer chip is connected to the output of the camera to convert the parallel MIPI D-PHY video signal into a serial electrical signal and drive the laser emitter in the bidirectional optical sub-assembly to work.

6. The MIPI D-PHY camera signal bidirectional transmission system based on active optical fiber according to claim 5, characterized in that: The serializer chip also integrates a first reverse control channel interface, which is used to receive the downlink control signal converted by the downlink optical receiving component from the bidirectional optical sub-component and forward it to the camera.

7. A bidirectional MIPI D-PHY camera signal transmission system based on active optical fiber according to claim 6, characterized in that: The input terminal of the deserializer chip is connected to the output terminal of the photodetector of the bidirectional optical sub-assembly, and is used to perform clock data recovery and serial-to-parallel conversion on the received serial electrical signal, and restore it to a parallel MIPI D-PHY video signal for output to the host terminal.

8. The MIPI D-PHY camera signal bidirectional transmission system based on active optical fiber according to claim 7, characterized in that: The deserializer chip also integrates a second reverse control channel interface, which is used to receive downlink control signals from the host and drive the laser emitter in the bidirectional optical sub-assembly to work.

9. The MIPI D-PHY camera signal bidirectional transmission system based on active optical fiber according to claim 1, characterized in that: The bidirectional optical sub-assembly is packaged in a TO-56 package and has an operating temperature range of -40°C to 105°C.

10. A bidirectional MIPI D-PHY camera signal transmission system based on active optical fiber according to claim 7, characterized in that: It also includes a CAN bus compatible module, which includes: A CAN transceiver is used to convert CAN bus differential signals into TTL / CMOS levels. The MCU, connected to the CAN transceiver, is used to convert the TTL / CMOS level into I2C or SPI signals to access the control interface of the serializer chip or the deserializer chip, thereby controlling the camera.

11. The MIPI D-PHY camera signal bidirectional transmission system based on active optical fiber according to claim 1, characterized in that: It also includes at least one fiber optic switch node, which receives N fiber optic signals, converts the optical signals into electrical signals, processes them, converts them back into optical signals, and then sends them to the host via fiber optic signals. Each fiber optic cable is connected to a bidirectional optical sub-component at both ends. The fiber optic switch nodes are interconnected to realize star topology cascaded transmission of multiple cameras, where N≥2.

12. A method for bidirectional transmission of MIPI D-PHY camera signals based on active optical fiber, applied to the transmission system as described in any one of claims 1 to 11, characterized in that, Includes the following steps: The forward transmission step, used to transmit the camera's MIPI D-PHY video signal to the host, includes: The S1.1 camera input serializer chip performs parallel-to-serial conversion and embeds synchronization codes to generate a serial data stream; The serial data stream described in S1.2 drives a laser transmitter of the first wavelength to generate an uplink modulated optical signal and couple it into the optical fiber; The filter inside the bidirectional optical sub-assembly of the S1.3 receiver module transmits the first wavelength optical signal from the optical fiber to the photodetector, where it is converted into an electrical signal. The electrical signal described in S1.4 is amplified by a transimpedance amplifier and a limiting amplifier, and then input to a deserializer chip for clock data recovery and serial-to-parallel conversion, restoring it to a MIPI D-PHY video signal for output to the host. The reverse transmission step, used to transmit control signals from the host to the camera, includes: S2.1 The control signal from the host is input to the control interface of the deserializer chip to generate a drive signal; The driving signal described in S2.2 drives the laser emitter of the second wavelength to generate a downlink modulated optical signal, which is then coupled into the optical fiber. The filter inside the bidirectional optical sub-assembly of the S2.3 transmitter module reflects the second wavelength optical signal from the optical fiber to the photodetector, where it is converted into an electrical signal. S2.4 The electrical signal is input to the control interface of the serializer chip, and then forwarded by the serializer chip to the camera, where it is converted back into a control signal.

13. The method for bidirectional transmission of MIPI D-PHY camera signals based on active optical fiber according to claim 12, characterized in that: It also includes a two-way synchronization step, specifically including: The uplink video stream uses a constant bit rate continuous transmission mode, while the downlink control stream uses a burst transmission mode. The two are completely isolated at the physical layer through wavelength division multiplexing. Set up a FIFO buffer with a depth of ≥512 bytes at the receiving end module or the host end to absorb delay jitter on the transmission path; Timestamp information is embedded in video frames, and the receiving module or host terminal restores the frame synchronization relationship based on the timestamp information.

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