CN114257558A - ARINC 818-based video and communication data transmission method and device - Google Patents

The invention relates to a method and a device for transmitting video and communication data through an optical fiber medium based on an ARINC818 protocol, wherein the method inserts communication data frames during the idle period of the video data frames on the basis of carrying out video transmission compatible with the ARINC818 protocol. By using different delimiters for the video data frame and the communication data frame, the receiving end can conveniently separate the video data frame and the communication data frame according to the delimiters. The related communication device consists of a sending unit and a receiving unit, wherein the sending unit and the receiving unit respectively consist of a processor unit CPU, an FPGA and a photoelectric conversion module; the FPGA of the sending unit runs a communication data coding unit, an ARINC818 video coding unit, a mixed coding unit and a high-speed serial sending unit; the receiving unit FPGA runs a high-speed serial receiving unit, a communication data decoding unit and an ARINC818 video decoding unit. The invention is compatible with the existing standard ARINC818 video sending and receiving equipment, can be widely applied to the occasions needing to simultaneously transmit video and communication data between the equipment, and greatly reduces the interconnection complexity between the equipment.

ARINC 818-based video and communication data transmission method and device

Technical Field

The invention belongs to the technical field of video interfaces, and particularly relates to a video and communication data transmission method and device based on ARINC 818.

Background

ADVB Container transmits based on the FHCP protocol of FC-4, wherein the Container Header and Object0 use a single FHCP Frame to transmit, and Object2 or Object3 uses the FHCP data Frame protocol to transmit, subject to the limitation that the data Frame load of FHCP is 2112 bytes at maximum, a single line of video data may be divided into multiple FHCP data frames to transmit, taking RGB888 color video with SXGA (1280 × 1024) resolution as an example, a line of video data has 3840 effective bytes, and when transmitting, the video data is generally divided into two FHCP video data frames with the same data field length and 1920 bytes.

The ARINC818 protocol supports the extension of user-defined communication data in Object0, but since Object0 only appears once in an ADVB Container, real-time, high-speed communication data transfer cannot be supported when Object0 extends user-defined data.

On the other hand, in addition to transmitting video signals, some communication data often need to be transmitted between the onboard electronic devices, and the communication data often requires higher real-time performance and certain communication data rate. The traditional transmission method often adopts some additionally defined bus interfaces, such as FC-AE, ARINC429 and the like, and the introduction of these interfaces can greatly increase the complexity of device interconnection, but cannot fully utilize the high bandwidth of the optical fiber transmission link based on ARINC 818. Therefore, it is desirable to invent a method and apparatus for video transmission based on ARINC818 protocol and supporting extended transmission of communication data.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a video and communication data transmission method and device based on ARINC 818.

The device comprises a sending unit and a receiving unit, wherein the sending unit and the receiving unit respectively comprise a processor unit CPU, an FPGA and a photoelectric conversion module;

the CPU of the sending unit sends communication data to the FPGA of the sending unit; the transmitting unit FPGA runs a communication data coding unit, an ARINC818 video coding unit, a mixed coding unit and a high-speed serial transmitting unit and is used for serially transmitting the communication data and the video data to the photoelectric conversion module after mixed coding; the photoelectric conversion module of the sending unit converts the electric signal into an optical signal and sends the optical signal to the receiving unit through an optical fiber;

the photoelectric conversion module of the receiving unit converts the optical signal into an electric signal; the receiving unit FPGA runs a high-speed serial receiving unit, a communication data decoding unit and an ARINC818 video decoding unit and is used for separating effective video data and communication data from serial data; and transmits the communication data to the receiving unit CPU.

Further, a communication data coding unit on the FPGA receives the communication data sent by the CPU of the sending unit to carry out communication data frame coding; an ARINC818 video coding unit on the FPGA of the sending unit receives external video data to carry out ARINC818 video data frame coding; the hybrid coding unit inserts the communication data frame into the idle period of the video data frame; the high-speed serial sending unit of the FPGA is used for sending the serial-parallel converted data to the photoelectric conversion module; the photoelectric conversion module converts the high-speed serial electric signal into an optical signal and transmits the optical signal to the receiving module through an optical fiber.

Further, a high-speed serial receiving unit of the receiving unit FPGA converts serial data into parallel data; the communication data decoding unit is used for extracting communication data from the mixed communication data and sending the communication data to the receiving unit CPU; the ARINC818 video decoding unit is used to extract valid video data from the mixed communication data.

Based on the device, the method for performing mixed transmission of video and communication data based on ARINC818 comprises the following steps:

the transmission of the video data frame is compatible with ARINC818 protocol, and the communication data frame is inserted during the idle period of the video data frame transmission on the basis of carrying out video transmission compatible with ARINC818 protocol. The video data frame and the communication data frame use different delimiters, so that a receiving end conveniently separates the video data frame and the communication data frame according to the delimiters;

the video data frames adopt line synchronization timing sequence when ARINC818 coding transmission is carried out, and ARINC818 coding transmission transmits one line of video data in one line of time of an original video, wherein the minimum 6 IDLE sequences are adopted to fill among the video data frames in the line, and the rest inter-line time is completely filled with the IDLE sequences;

when the communication data frame is transmitted, if the communication data frame is currently in the effective video area, the communication data frame is inserted in the IDLE between the next video lines, and if the communication data frame is currently in the video blanking area, the communication data frame can be directly inserted.

Further, the video data frame refers to data framing performed by an ARINC818 protocol based on an FHCP protocol, and consists of SOF + frame header + data load + CRC check + EOF; a line of video data comprises a number of ARINC818 frames of video data.

Advantageous effects

The invention has good universality and expansibility, can realize the simultaneous transmission of video data and communication data on a single optical fiber link, simultaneously ensures that the transmission delay of the communication data is low, is compatible with ARINC818 transmission protocol for the video data, and can be widely applied to the interconnection among various airborne video equipment, display equipment and recording equipment.

The invention is compatible with the existing standard ARINC818 video sending and receiving equipment, can be widely applied to the occasions needing to simultaneously transmit video and communication data between the equipment, and greatly reduces the interconnection complexity between the equipment.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic block diagram of a method and apparatus for hybrid transmission of video and communication data based on ARINC818 according to the present invention;

FIG. 2 shows the SXGA video line synchronization ARINC818 transmit timing;

FIG. 3 communication data frame format;

FIG. 4 definition of a communication data frame;

fig. 5 a mixed data stream of video data frames and communication data frames.

Detailed Description

The following further describes embodiments of the present invention with reference to the drawings.

As shown in fig. 1, the apparatus for transmitting video and communication data via optical fiber medium based on ARINC818 protocol according to the present invention comprises a transmitting unit and a receiving unit, wherein the transmitting unit and the receiving unit respectively comprise a processor unit CPU, an FPGA and a photoelectric conversion module.

The CPU of the sending unit sends communication data to the FPGA of the sending unit; the transmitting unit FPGA runs a communication data coding unit, an ARINC818 video coding unit, a mixed coding unit and a high-speed serial transmitting unit and is used for serially transmitting the communication data and the video data to the photoelectric conversion module after mixed coding; the photoelectric conversion module of the sending unit converts the electric signal into an optical signal and sends the optical signal to the receiving unit through an optical fiber.

Specifically, a communication data encoding unit on the FPGA receives communication data sent by the CPU of the sending unit and encodes communication data frames; an ARINC818 video coding unit on the FPGA of the sending unit receives external video data to carry out ARINC818 video data frame coding; the hybrid coding unit inserts the communication data frame into the idle period of the video data frame; the high-speed serial sending unit of the FPGA is used for sending the serial-parallel converted data to the photoelectric conversion module; the photoelectric conversion module converts the high-speed serial electric signal into an optical signal and transmits the optical signal to the receiving module through an optical fiber.

The photoelectric conversion module of the receiving unit converts the optical signal into an electric signal; the receiving unit FPGA runs a high-speed serial receiving unit, a communication data decoding unit and an ARINC818 video decoding unit and is used for separating effective video data and communication data from serial data; and transmits the communication data to the receiving unit CPU.

Specifically, a high-speed serial receiving unit of the receiving unit FPGA converts serial data into parallel data; the communication data decoding unit is used for extracting communication data from the mixed communication data and sending the communication data to the receiving unit CPU; the ARINC818 video decoding unit is used to extract valid video data from the mixed communication data.

Based on the device, the method for performing mixed transmission of video and communication data based on ARINC818 comprises the following steps:

the transmission of the video data frame is compatible with ARINC818 protocol, and the communication data frame is inserted during the idle period of the video data frame on the basis of carrying out video transmission compatible with the ARINC818 protocol. By using different delimiters for the video data frame and the communication data frame, the receiving end can conveniently separate the video data frame and the communication data frame according to the delimiters.

The video data frames adopt a line synchronization time sequence when ARINC818 coding transmission is carried out, namely in the time of one line of an original video, ARINC818 coding transmission of one line of video data, wherein minimum 6 IDLE sequences are adopted to fill among the video data frames in the line, all IDLE sequences are filled in the rest time among the lines, wherein the video data frame refers to data framing carried out by an ARINC818 protocol based on an FHCP protocol and consists of SOF + frame header + data load (video data) + CRC + EOF; a line of video data may include multiple ARINC818 frames of video data, depending on the transmission resolution and FHCP protocol. Video frames refer to fully scanned video in both the horizontal and vertical directions, depending on the refresh rate of the video, e.g., 60Hz progressive video transmits a video frame within 16.67 ms.

Taking the example of transmitting SXGA (1280 × 1024) resolution video, a line-synchronized transmission timing at ARINC818 line rate of 3.1875Gbps is shown in fig. 2. The LW CLK sent by the ARINC818 is 79.6875MHz, the pixel clock PCLK of the SXGA is 108MHz, the total pixel number of one line of video is 1688, and the effective video pixel number is 1280. The ARINC818 LW CLK for a total duration of one row is 1245 clock cycles. One line of video is divided into two FHCP video data frames for transmission, each video data frame corresponds to 489 LW CLK, the number of IDLE in a line is 6 LW CLK between two video data frames corresponding to a line, and at this time, the number of IDLE in a corresponding line is 261 LW CLK.

When the communication data frame is transmitted, if the communication data frame is currently in the effective video area, the communication data frame is inserted in the IDLE between the next video lines, and if the communication data frame is currently in the video blanking area, the communication data frame can be directly inserted.

Specifically, during the inter-line IDLE, the IDLE is inserted only to ensure that the video timing is synchronized with the ARINC818 transmission timing, and does not convey any valid video data information. Therefore, the invention inserts the communication data between IDLE, finish the mixed code transmission of the video frame and communication data frame; similarly, during IDLE periods of video blanking, no effective video data transmission is performed, and communication data frames may also be inserted.

The defined communication frame format is shown in fig. 3, and the SOFs and EOFs are newly defined frame delimiters, and the 8B10B encoding results thereof are shown in fig. 4. The Frame Header comprises 4 Bytes, wherein the BYTE0 is an identifier for representing communication data streams, multiple communication data streams can be supported to be transmitted on the same ARINC818 channel, the BYTE1 and the BYTE2 are reserved, the actual transmission is filled with 0, and the BYTE3 represents the length of a communication data field and is represented by Bytes. The data field length is 0-256 bytes, if the byte number is not an integer multiple of 4, the MSB of the last LW transmits the effective communication data, and the LSB is filled with 0. The same CRC32 check is used as for ARINC818 FHCP frames.

For the above transmission scheme, each control data frame has a length of 68 LW CLK's at maximum and a maximum payload of 64 LW (256 bytes). In the limit, a control data frame can be inserted into the inter-line IDLE of each line, and the maximum corresponding control data transmission rate is 1024 × 256 × 60 — 15728640 bytes/s, which can meet the requirement of the transmission rate of ordinary communication data, and when communication data is transmitted, the inter-line IDLE of the next video can effectively send out the communication data frame, so the transmission delay of the communication data frame is not more than 1 line of video.

According to the foregoing, the data flow of the hybrid coded transmission for inserting the communication data into IDLE between the video data frame lines of the ARINC818 protocol is shown in fig. 5, and the transmission of the video data and the communication data in a single optical fiber is realized through the hybrid coded transmission of the video data and the communication data.

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, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention.