Laser communication data frame processing method and device

Abstract

The present invention provides a laser communication data frame processing method and device, the method comprising: in a data transmission link, clock recovery is performed on the data to be transmitted after channel coding, payload information is extracted through frame detection and written into a transmission memory, a frame maker reads the data in the memory and groups them into frames for transmission, when the form query shows that the first FIFO queue is not empty, the frame sequence to be retransmitted is read and the corresponding memory address is obtained, and the corresponding data in the transmission memory is read for retransmission; in a data receiving link, frame detection is performed on the received data, CMI decoding is performed on the detected data frame, and the data frame is parsed and verified by a deframer, if the verification passes, the payload information of the data frame is written into the receiving memory, and the frame sequence is written into the second FIFO queue, and the correct frame sequence fed back by the remote end is written into the receipt form. The scheme can improve the data transmission efficiency and transmission reliability of the communication link.

Description

Technical Field

[0001] The invention belongs to the field of laser communication, and in particular relates to a laser communication data frame processing method and device. Background Art

[0002] Laser communication is an important technology in the field of high-bandwidth information transmission in space. When lasers are transmitted in atmospheric channels at lower altitudes, they are affected by factors such as absorption and scattering of atmospheric molecules and atmospheric turbulence, which can cause random errors and burst errors in laser communication signal transmission. Forward error correction coding (FEC) is an effective means to overcome random errors, but for long-distance near-ground / near-sea dynamic laser communication links, the adverse effects of burst errors are more obvious due to combined factors such as atmospheric channel degradation, tracking and aiming line of sight disturbance, and short-term external occlusion. Forward error correction coding is limited by code length, and the error correction effect on longer burst errors is not significant.

[0003] As the bit error rate requirements for laser communication links become higher and higher (generally, the bit error rate requirement for atmospheric laser communication is better than 10 -6 ), the currently commonly used automatic request retransmission technology (ARQ technology) is one of the effective means to further reduce the link bit error rate and improve the reliability under harsh atmospheric channel conditions.

[0004] At present, the specific implementation of ARQ technology includes different modes such as stop-and-wait, back-off-N-steps, and selective retransmission, which can be combined with FEC error correction technology to adopt a hybrid automatic request retransmission mode. The bandwidth utilization rate of ARQ modes such as stop-and-wait and back-off-N-steps is low. By adopting selective retransmission and FEC hybrid retransmission (HARQ), the error correction efficiency is higher and the bandwidth utilization rate can be improved. However, the hybrid retransmission of ARQ selective retransmission and FEC forward error correction still has poor communication efficiency and reliability in specific scenarios. For example, when a small number of partial bit errors may cause the retransmission of the entire packet, it will lead to reduced transmission efficiency, and when there are too many continuous burst errors caused by atmospheric turbulence, a large number of errors are dispersed in each frame after interleaving, resulting in an increase in bit errors, which in turn affects data reliability and transmission efficiency. Summary of the invention

[0005] In view of this, an embodiment of the present invention provides a laser communication data frame processing method and device, which are used to solve the problem of poor communication efficiency and reliability of existing hybrid retransmission in specific scenarios.

[0006] In a first aspect of an embodiment of the present invention, a laser communication data frame processing method is provided, comprising:

[0007] In the data transmission link, the clock of the data to be transmitted after channel coding is recovered, the payload information is extracted through frame detection and written into the transmission memory, the frame maker reads the data in the transmission memory and groups them into frames for transmission. When the form query first FIFO queue is not empty, the frame sequence to be retransmitted is read and the corresponding memory address is obtained, and the corresponding data in the transmission memory is read for retransmission;

[0008] The framer sends the frame sequence of the correct frame checked by the deframer to the remote end, and performs CMI encoding and parallel-to-serial conversion on the framed data in the framer, and sends it to the source modulation driver for signal transmission;

[0009] In the data receiving link, frame detection is performed on the received data, CMI decoding is performed on the detected data frame, and the data frame is parsed and verified by the deframer. If the verification passes, the payload information of the data frame is written into the receiving memory, and the frame sequence is written into the second FIFO queue, and the correct frame sequence fed back by the remote end is written into the receipt form;

[0010] The data read from the receiving memory are sequentially subjected to parallel-to-serial conversion, serial CMI encoding and channel decoding.

[0011] In a second aspect of an embodiment of the present invention, a laser communication data frame processing device is provided, comprising:

[0012] A detection receiving module is used to receive laser signals and perform photoelectric conversion on the laser signals;

[0013] A clock recovery module is used to perform clock recovery on the data to be sent after channel coding, and to extract the clock signal in the received data;

[0014] A level matching circuit is used to convert the received data into a serial clock and serial data, and transmit the data to the FPGA and DSP combination circuit;

[0015] An FPGA and DSP combination circuit is used for deframing received data, automatically requesting retransmission, and selecting retransmission, wherein the FPGA and DSP combination circuit includes a deframer and a framer;

[0016] A channel coding and decoding module is used to perform channel coding on the data to be transmitted and channel decoding on the received data;

[0017] DDR memory, used for buffering the payload information of data to be sent or received, the DDR memory comprising a sending memory and a receiving memory;

[0018] Ethernet interface, used for parallel-to-serial conversion of frame data, sending the converted data to the channel encoding and decoding module, and performing channel encoding on the data to be sent;

[0019] The modulation drive module is used to perform electro-optical conversion on the data to be transmitted, and the optical antenna completes the laser emission;

[0020] The FPGA and DSP combination circuit extracts the payload information of the transmitted data through frame detection and writes it into the transmission memory, reads the data in the transmission memory and groups them into frames for transmission, and when the form query first FIFO queue is not empty, reads the frame sequence to be retransmitted and obtains the corresponding memory address, and reads the corresponding data in the transmission memory for retransmission;

[0021] And, the received data frame is parsed and verified. If the verification passes, the payload information of the data frame is written into the receiving memory, the frame sequence is written into the second FIFO queue, and the correct frame sequence fed back by the remote end is written into the receipt form.

[0022] In a third aspect of an embodiment of the present invention, an electronic device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method described in the first aspect of the embodiment of the present invention when executing the computer program.

[0023] In a fourth aspect of an embodiment of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method provided in the first aspect of the embodiment of the present invention are implemented.

[0024] In the embodiments of the present invention, by using technologies such as grouping frames and short frame selective retransmission, the data transmission efficiency of the communication link is improved, the bit error rate in harsh atmospheric conditions is reduced, and the reliability and stability of the communication link are guaranteed, thereby improving the transmission efficiency and stability of existing hybrid retransmission in specific scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 A schematic flow chart of a laser communication data frame processing method provided by one embodiment of the present invention;

[0027] Figure 2 Another schematic flow chart of a laser communication data frame processing method provided by one embodiment of the present invention;

[0028] Figure 3A schematic diagram of the structure of a laser communication data frame processing device provided for one embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] It should be understood that the term "including" and other similar expressions in the specification or claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions, such as a process, method, system, or device including a series of steps or units is not limited to the listed steps or units. In addition, "first" and "second" are used to distinguish different objects, not to describe a specific order.

[0031] See also Figure 1 , a flow chart of a laser communication data frame processing method provided by an embodiment of the present invention includes:

[0032] S101, in the data transmission link, clock recovery is performed on the data to be transmitted after channel coding, payload information is extracted through frame detection and written into the transmission memory, a frame maker reads the data in the memory and groups them into frames for transmission, when the form query shows that the first FIFO queue is not empty, the frame sequence to be retransmitted is read and the corresponding memory address is obtained, and the corresponding data in the transmission memory is read for retransmission;

[0033] The framer sends the frame sequence of the correct frame checked by the deframer to the remote end, and performs CMI encoding and parallel-to-serial conversion on the framed data in the framer, and sends it to the source modulation driver for signal transmission;

[0034] After the data is sent, the receipt form in the DPRAM is queried. If the first FIFO queue is not empty, the frame sequence to be resent is read from it, the address of the frame in the send memory is calculated, the memory is read and the data is resent. The data after being grouped into frames is encoded with CMI (Coded Mark Inversion), converted from parallel to serial, and sent to the source modulation driver for signal transmission.

[0035] Among them, after FEC (forward error correction) is used to perform channel coding on the data to be sent, it is converted from serial to parallel through the Ethernet interface and enters the core processing circuit (FPGA+DSP) to complete frame detection, data caching, data framing and other processing, and the selection and retransmission of data frames are completed through the ARQ mechanism. It is transmitted to the external modulation driver through the driving circuit to complete the data electrical-optical conversion, and the optical antenna completes the laser emission.

[0036] Among them, the frame sequence that needs to be retransmitted can be determined according to the frame sequence in the receipt form and the actual sent frame sequence, that is, it is determined whether the first FIFO queue is empty, and if it is not empty, the corresponding frame sequence is directly obtained.

[0037] It can be understood that the combination of short frame grouping and selective retransmission mechanisms can avoid problems such as large-scale data retransmission caused by a small number of bit errors and discrete distribution of errors caused by interleaving, thereby improving channel utilization.

[0038] S102, in the data receiving link, performing frame detection on the received data, performing CMI decoding on the detected data frame, parsing and verifying the data frame through the deframer, and if the verification passes, writing the payload information of the data frame into the receiving memory, writing the frame sequence into the second FIFO queue, and writing the correct frame sequence fed back by the remote end into the receipt form;

[0039] The data read from the receiving memory are sequentially subjected to parallel-to-serial conversion, serial CMI encoding and channel decoding.

[0040] Preferably, the link state is estimated based on the frame error rate and the signal-to-noise ratio statistically calculated by the deframer, and at least the cache depth and the framing length of the retransmission buffer are adjusted according to the link state estimation result.

[0041] The deframer synchronously sends the statistical frame error rate to the state estimation module, which facilitates real-time and rapid adjustment of parameters such as buffer cache depth and framing length to avoid a large number of retransmissions caused by a small amount of erroneous data and the discrete distribution of erroneous data.

[0042] Preferably, the frame buffer is read from the receiving memory continuously, and a switching control signal is sent to the deframer so that the deframer writes the frame buffer data. The data deframe processing efficiency can be improved by the buffer ping-pong operation.

[0043] Among them, the frame sequence recorded in the receipt form (local) is the correct frame sequence for remote frame decoding, that is, the data frame sent by the local to the remote communication object is partially not received correctly due to factors such as bit errors or frame loss. The remote communication object will send the correct frame sequence received in the form of a receipt form to inform the local, and determine through the form query that the incorrectly received frame needs to be retransmitted from the local to the remote. The frame sequence recorded in the second FIFO queue is the correct frame sequence for local frame decoding. It is the data frame sent by the remote communication object to the local. After the correct frame sequence after frame detection and verification, it is sent to the remote end. The remote communication object uses it for its own receipt form query and for the remote to local data frame retransmission operation. Whether retransmission is needed is mainly confirmed by frame detection and frame verification. The frame sequence with correct detection of the frame header information and correct verification will be filled in the second FIFO and sent together with the data stream to inform the communication object.

[0044] In some embodiments, Figure 2 As shown, in the transmission link, after the data to be transmitted after channel coding is clock recovered, the payload information is extracted through frame detection and written into the transmission memory, the framer reads the data in the transmission memory and groups them into frames for transmission, and the framed data in the framer are respectively CMI-encoded and parallel-to-serial converted, and sent to the source modulation driver for signal transmission;

[0045] When the form query shows that the first FIFO queue is not empty, the frame sequence to be retransmitted is read and the corresponding memory address is obtained, and the corresponding data in the transmission memory is read and retransmitted.

[0046] In the receiving link, frame detection is performed on the received data, CMI decoding is performed on the detected data frame, and the data frame is parsed and verified by the deframer. If the verification passes, the payload information of the data frame is written into the receiving memory, and the frame sequence is written into the second FIFO queue, and the correct frame sequence fed back by the remote end is written into the receipt form; the data read from the receiving memory is sequentially converted from parallel to serial, serial CMI encoded, and channel decoded.

[0047] The cache depth, framing length and other parameters of the retransmission buffer are adjusted through link state estimation; and data in the receiving memory are read or written through buffer ping-pong (i.e., switching control of buffer reading and writing).

[0048] In this embodiment, by using technologies such as short frame grouping, selective retransmission, and buffer ping-pong operation, the real-time performance and transmission efficiency of the entire communication link data transmission can be improved, the bit error rate under the harsh atmospheric channel can be greatly reduced, and the reliability and stability of the communication link can be improved. By automatically adjusting the retransmission parameters such as buffer depth and packet frame length through link state estimation, the communication link can better balance the transmission efficiency and reliability, and improve the adaptability to the atmospheric channel.

[0049] It should be understood that the serial numbers of the steps in the above embodiments do not imply a sequence of execution, and the execution sequence of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0050] Figure 3 A schematic diagram of the structure of a laser communication data frame processing device provided by an embodiment of the present invention, the device comprising:

[0051] The detection receiving module 310 is used to receive the laser signal and perform photoelectric conversion on the laser signal;

[0052] The clock recovery module 320 is used to perform clock recovery on the data to be transmitted after channel coding, and to extract the clock signal in the received data;

[0053] The level matching circuit 330 is used to convert the received data into a serial clock and serial data, and transmit them to the FPGA and DSP combination circuit;

[0054] FPGA and DSP combination circuit 340, used for de-framing received data and automatically requesting retransmission, and selecting retransmission, wherein the FPGA and DSP combination circuit includes a de-framer and a framer;

[0055] A channel coding and decoding module 370, configured to perform channel coding on data to be transmitted and channel decoding on received data;

[0056] DDR memory 350, used for buffering the payload information of the data to be sent or received, the DDR memory includes a sending memory and a receiving memory;

[0057] The Ethernet interface 360 ​​is used to convert the frame data into parallel and serial data, and send the converted data to the channel coding and decoding module, and to perform channel coding on the data to be sent;

[0058] The modulation driving module 380 is used to perform electro-optical conversion on the data to be transmitted, and complete the laser emission by the optical antenna;

[0059] The FPGA and DSP combination circuit 340 extracts the payload information of the transmitted data through frame detection and writes it into the transmission memory, reads the data in the transmission memory and groups them into frames for transmission, and when the form query first FIFO queue is not empty, reads the frame sequence to be retransmitted and obtains the corresponding memory address, and reads the corresponding data in the transmission memory for retransmission;

[0060] And, the received data frame is parsed and verified. If the verification passes, the payload information of the data frame is written into the receiving memory, the frame sequence is written into the second FIFO queue, and the correct frame sequence fed back by the remote end is written into the receipt form.

[0061] The frame buffer is read from the DDR memory continuously, and a switching control signal is sent to the deframer so that the deframer can write the frame buffer data.

[0062] Preferably, the link state is estimated based on the frame error rate and the signal-to-noise ratio statistically calculated by the deframer, and at least the cache depth and the framing length of the retransmission buffer are adjusted according to the link state estimation result.

[0063] In the data receiving process, when the detection receiving module 310 receives the laser signal from the atmospheric channel, it performs photoelectric conversion on the detection signal, extracts the clock signal through the clock recovery module 320, converts the data and clock signals into serial clock and data code stream through the level matching circuit 330, and sends them to the FPGA and DSP combination circuit 340 for deframing, data automatic request retransmission (ARQ) and other processing, and the DDR memory 350 caches the data frame. Among them, the DSP manages and configures the internal logic of the core processing circuit and completes the instruction interaction with the integrated control module. The frame data after ARQ processing is converted from parallel to serial through the Ethernet interface 360 ​​and sent to the channel codec module 370 for FEC decoding processing.

[0064] During the data transmission process, the data to be sent is channel-coded by the channel coding module 370, and after being received and converted by the Ethernet port, it enters the FPGA and DSP combination circuit 340 to complete data framing, caching and other processing, and completes the selection and retransmission of the data frame through the ARQ mechanism. The data to be sent is converted from electricity to light by the modulation driving circuit 380, and the laser emission is completed by the optical antenna.

[0065] Among them, the short frame grouping of data messages is implemented through the FPGA logic unit, and the pipeline processing of CMI encoding is carried out to ensure the balance of transmitted optical power and transmission efficiency.

[0066] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and modules described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0067] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0068] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laser communication data frame processing method, characterized in that: include: In the data transmission link, the clock of the data to be transmitted after channel coding is recovered, the payload information is extracted through frame detection and written into the transmission memory, the frame maker reads the data in the transmission memory and groups them into frames for transmission. When the form query first FIFO queue is not empty, the frame sequence to be retransmitted is read and the corresponding memory address is obtained, and the corresponding data in the transmission memory is read for retransmission; The framer sends the frame sequence of the correct frame checked by the deframer to the remote end, and performs CMI encoding and parallel-to-serial conversion on the framed data in the framer, and sends it to the source modulation driver for signal transmission; In the data receiving link, frame detection is performed on the received data, CMI decoding is performed on the detected data frame, and the data frame is parsed and verified by the deframer. If the verification passes, the payload information of the data frame is written into the receiving memory, and the frame sequence is written into the second FIFO queue, and the correct frame sequence fed back by the remote end is written into the receipt form; The data read from the receiving memory is sequentially subjected to parallel-to-serial conversion, serial CMI encoding and channel decoding; The link state is estimated based on the frame error rate and signal-to-noise ratio statistically calculated by the deframer, and at least the cache depth and framing length of the retransmission buffer are adjusted according to the link state estimation result.

2. The method according to claim 1, characterized in that Writing the payload information of the data frame into the receiving memory also includes: The receiving memory is continuously cached and read, and a switching control signal is sent to the deframer so that the deframer can write the cached data.

3. A laser communication data frame processing device, characterized in that: include: A detection receiving module is used to receive laser signals and perform photoelectric conversion on the laser signals; A clock recovery module is used to perform clock recovery on the data to be sent after channel coding, and to extract the clock signal in the received data; A level matching circuit is used to convert the received data into a serial clock and serial data, and transmit the data to the FPGA and DSP combination circuit; An FPGA and DSP combination circuit is used for deframing received data, automatically requesting retransmission, and selecting retransmission, wherein the FPGA and DSP combination circuit includes a deframer and a framer; A channel coding and decoding module is used to perform channel coding on the data to be transmitted and channel decoding on the received data; DDR memory, used for buffering the payload information of data to be sent or received, the DDR memory comprising a sending memory and a receiving memory; Ethernet interface, used for parallel-to-serial conversion of frame data, sending the converted data to the channel encoding and decoding module, and performing channel encoding on the data to be sent; The modulation drive module is used to perform electro-optical conversion on the data to be transmitted, and the optical antenna completes the laser emission; The FPGA and DSP combination circuit extracts the payload information of the transmitted data through frame detection and writes it into the transmission memory, reads the data in the transmission memory and groups them into frames for transmission, and when the form query first FIFO queue is not empty, reads the frame sequence to be retransmitted and obtains the corresponding memory address, and reads the corresponding data in the transmission memory for retransmission; And, parsing and checking the received data frame, if the check passes, writing the payload information of the data frame into the receiving memory, writing the frame sequence into the second FIFO queue, and writing the correct frame sequence fed back by the remote end into the receipt form; Wherein, the FPGA and DSP combination circuit includes: The link state is estimated based on the frame error rate and signal-to-noise ratio statistically calculated by the deframer, and at least the buffer depth and framing length of the retransmission buffer are adjusted according to the link state estimation result.

4. The device according to claim 3, characterized in that Writing the payload information of the data frame into the receiving memory also includes: The frame buffer is read from the DDR memory continuously, and a switching control signal is sent to the deframer so that the deframer can write the frame buffer data.

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