Symbol rate adaptive method and system of ultraviolet communication system

Abstract

The invention discloses a symbol rate adaptive method and system of an ultraviolet communication system. The method comprises the following steps: setting an initial symbol rate gear of the ultraviolet communication system according to a communication distance, expected light intensity or a task scene; a sending end continuously sends data frames according to an initial symbol rate gear, records the number of sent frames, stops sending when accumulated sending reaches a fixed frame number, and waits for feedback; after receiving any frame, the receiving end extracts a frame sequence number and sends a feedback frame to the sending end after waiting for a specified frame interval; the sending end analyzes the channel estimation parameter of the current link from the received feedback frame; and the rate adaptive control module judges the quality of the current link according to the obtained channel estimation parameter of the current link, and dynamically adjusts and switches the symbol rate according to the channel criterion required by the LDPC. According to the method, the dynamic adjustment of the symbol rate is realized by extracting the channel estimation parameters in real time, so that the optimal communication performance of the system under different environment conditions is ensured.

Description

Technical Field

[0001] This invention relates to the field of wireless optical communication technology, and in particular to a symbol rate adaptive method and system for an coded ultraviolet communication system. Background Technology

[0002] Wireless optical communication is a technology that transmits data in free space using light waves as the carrier. It is mainly divided into infrared, visible light, and ultraviolet light communication. Solar-blind ultraviolet light communication operates in the 200-280 nanometer band. Because solar radiation in this band is completely absorbed by the ozone layer, it has a natural advantage of extremely high signal-to-noise ratio near the Earth's surface. Its core advantage lies in its non-line-of-sight transmission capability: it utilizes the scattering effect of atmospheric molecules and aerosols, allowing the communication link to bypass physical obstacles without precise alignment, making it suitable for emergency networking in mobile and complex environments. However, its advantages also bring challenges. Strong scattering, while enabling non-line-of-sight connections, also causes significant path loss, limiting communication distance and speed. Furthermore, the channel is highly sensitive to changing atmospheric conditions (such as aerosols, temperature, humidity, and turbulence), leading to dynamic fluctuations in link bandwidth and signal-to-noise ratio, resulting in poor link stability.

[0003] In ultraviolet (UV) communication systems, to maintain reliable communication connections and maximize data transmission efficiency under varying channel conditions, the symbol rate of the communication system needs to adapt to channel conditions in real time. When channel conditions are poor, the symbol rate should be reduced to improve communication reliability; when channel conditions are good, the symbol rate should be increased to enhance data transmission throughput. However, most existing UV communication systems still use a fixed symbol rate for transmission. This static configuration cannot respond to dynamic channel changes: when channel quality is good, channel capacity cannot be fully utilized to achieve higher data throughput; when channel quality deteriorates, the inability to reduce the symbol rate to ensure link reliability significantly increases the risk of communication interruption. This fixed rate mode severely restricts the overall performance and robustness of the system in complex and variable environments.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a symbol rate adaptive method and system for ultraviolet communication systems to solve the aforementioned technical problems in the prior art. The method of this invention dynamically adjusts the symbol rate by extracting channel estimation parameters in real time. It automatically increases the symbol rate to improve throughput when link conditions are good, and decreases the rate to reduce frame error rate when link conditions deteriorate, thereby ensuring that the system maintains optimal communication performance under different environmental conditions.

[0006] The objective of this invention is achieved through the following technical solution: A symbol rate adaptive method for an ultraviolet communication system, the method comprising: Step 1: Set the initial symbol rate setting of the ultraviolet communication system according to the communication distance, expected light intensity, or mission scenario; Step 2: The sending end continuously sends data frames at the initial symbol rate setting, records the number of frames sent, and stops sending when the cumulative number of frames sent reaches a fixed number, and waits for feedback; Step 3: After receiving any frame, the receiving end extracts the frame sequence number and sends a feedback frame to the sending end after waiting for a specified frame interval; wherein, the feedback frame contains channel estimation parameters, namely the signal photon count rate of the current link. and background noise photon count rate ; Step 4: The transmitting end parses the current link's signal photon count rate from the received feedback frame. and background noise photon count rate These two parameters are then input into the rate adaptive control module; Step 5: The rate adaptive control module determines the quality of the current link based on the obtained channel estimation parameters of the current link, and performs dynamic adjustment and switching of the symbol rate according to the channel criteria required by the low-density parity-check code (LDPC).

[0007] A symbol rate adaptive system for an ultraviolet communication system, the system comprising: The rate setting module is used to set the initial symbol rate setting of the ultraviolet communication system according to the communication distance, expected light intensity, or mission scenario. The transmitting module continuously sends data frames at the initial symbol rate level, records the number of frames sent, stops sending when the cumulative number of frames sent reaches a fixed number, and waits for feedback; then it parses the current link's signal photon count rate from the received feedback frames. and background noise photon count rate These two parameters are then input into the rate adaptive control module; The receiving module is used to extract the frame sequence number after receiving any frame, and send a feedback frame to the sending module after waiting for a specified frame interval; wherein, the feedback frame contains channel estimation parameters, namely the signal photon count rate of the current link. and background noise photon count rate ; The rate adaptive control module is used to determine the quality of the current link based on the obtained channel estimation parameters of the current link, and to dynamically adjust and switch the symbol rate according to the channel criteria required by LDPC.

[0008] Compared with existing technologies, the method and system provided by this invention achieve dynamic adjustment of symbol rate by extracting channel estimation parameters in real time. When the link conditions are good, the symbol rate is automatically increased to improve throughput, and the rate is reduced to reduce frame error rate when the link deteriorates. This ensures that the system maintains the best communication performance under different environmental conditions, and realizes the comprehensive optimization requirements of system capacity and robustness for ultraviolet light communication under high loss and slow fading channels. Attached Figure Description

[0009] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 A flowchart illustrating the symbol rate adaptive method for an ultraviolet communication system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the frame structure of the forward link and the feedback link according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the simulation results of switching boundary conditions as described in an embodiment of the present invention; Figure 4 The link parameters described in the embodiments of the present invention and Trend graph showing how the number of feedback frames changes. Detailed Implementation

[0011] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them, and do not constitute a limitation on the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0012] First, the following explanations are provided for the terms that may be used in this article: The term "and / or" means that either or both can be achieved simultaneously. For example, X and / or Y means that it includes both "X" or "Y" as well as the three cases of "X and Y".

[0013] The terms "comprising," "including," "containing," "having," or other similar semantic descriptions should be interpreted as non-exclusive inclusion. For example, including a technical feature element (such as raw material, component, ingredient, carrier, dosage form, material, size, part, component, mechanism, device, step, process, method, reaction conditions, processing conditions, parameter, algorithm, signal, data, product or article of manufacture, etc.) should be interpreted as including not only the expressly listed technical feature element, but also other technical feature elements that are not expressly listed and are well-known in the art.

[0014] The term "composed of" excludes any technical features not expressly listed. When used in a claim, it closes the claim to exclude all technical features other than those expressly listed, except for associated conventional impurities. If the term appears only in a clause of a claim, it limits the claim to the elements expressly listed in that clause; elements recited in other clauses are not excluded from the overall claim.

[0015] The technical solution provided by this invention will be described in detail below. Contents not described in detail in the embodiments of this invention are prior art known to those skilled in the art. Where specific conditions are not specified in the embodiments of this invention, they shall be performed according to conventional conditions in the art or conditions recommended by the manufacturer. Reagents or instruments used in the embodiments of this invention whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0016] like Figure 1 The diagram shown is a schematic flowchart of a symbol rate adaptive method for an ultraviolet communication system provided in an embodiment of the present invention. The method includes: Step 1: Set the initial symbol rate setting of the ultraviolet communication system according to the communication distance, expected light intensity, or mission scenario; In this step, the symbol rate settings include: {25K, 100K, 250K, 500K, 1M}; The above symbol rate settings are pre-configured by the system and can be flexibly expanded according to the hardware platform capabilities and protocol requirements.

[0017] Step 2: The sending end continuously sends data frames at the initial symbol rate setting, records the number of frames sent, and stops sending when the cumulative number of frames sent reaches a fixed number (e.g., 64 frames) and waits for feedback; In this step, each forward link data frame contains Low-Density Parity-Check Code (LDPC) encoding information, a frame sequence number field, and a CRC checksum to ensure the stable operation of the forward and feedback links.

[0018] The CRC checksum in the frame structure ensures the correctness of the frame number. This design effectively avoids synchronization deviation problems caused by missing frames or counting offsets at the receiving end, and improves the stability of feedback control.

[0019] Step 3: After receiving any frame, the receiving end extracts the frame sequence number and sends a feedback frame to the sending end after waiting for a specified frame interval; wherein, the feedback frame contains channel estimation parameters, namely the signal photon count rate of the current link. and background noise photon count rate ; In this step, such as Figure 2 The diagram shows the frame structure of the forward link and feedback link according to an embodiment of the present invention. To ensure the correctness of the feedback trigger position, the first 8 bits of the L-bit valid information of each frame of data sent by the sending end are the frame sequence number field (ranging from 0 to 63), which is used to identify the relative position of the frame data in a fixed frame number period. In a specific implementation, the fixed frame number can be set to 64 frames. The receiving end only needs to correctly receive any frame to parse the frame number x in the current period, and according to the known transmission period rule, send the corresponding feedback frame after a delay of a fixed number of frames - x frames; if it is 64 frames, then send the corresponding feedback frame after a delay of 64 - x frames. Among them, such as Figure 2 As shown, in the L bits of valid information in the feedback frame, the first 32 bits are channel estimation parameters. and The other structures are similar to those of the sent frame.

[0020] The channel estimation obtained above and Rounding can be performed according to the actual limitations of the platform.

[0021] Step 4: The transmitting end parses the current link's signal photon count rate from the received feedback frame. and background noise photon count rate These two parameters are then input into the rate adaptive control module; Step 5: The rate adaptive control module determines the quality of the current link based on the obtained channel estimation parameters of the current link, and performs dynamic adjustment and switching of the symbol rate according to the channel criteria required by LDPC.

[0022] In this step, the dynamic adjustment and switching process of the symbol rate is specifically as follows: Speed ​​reduction judgment: If the link quality degrades to the current background noise photon count rate Under the given conditions, the current signal photon count rate If the value falls below the switching boundary condition, the symbol rate is reduced by one level; the switching boundary condition is determined by applying different values ​​under fixed symbol rate and sampling conditions. The scenario was obtained through multiple independent random trials, and the minimum value that could reliably achieve decoding was selected. The value plus a fixed value of 10 is used as the boundary point under the background condition; for example... Figure 3 The diagram shown is a simulation result of the switching boundary conditions described in an embodiment of the present invention. Under the conditions in this embodiment, the ADC sampling frequency is 200 MHz. and The maximum limit is set to 300.

[0023] Acceleration determination: If the current and At the same time, the corresponding multiplier is reduced, that is, the ratio of the higher speed setting to the current speed, after reducing the multiplier. If it is still higher than the switching boundary condition, the rate will be increased by one level; If the current and If neither the deceleration nor acceleration conditions are met, the speed remains constant.

[0024] In the specific implementation, the switching boundary conditions are obtained through LDPC bit error rate simulation and pre-written into the storage unit. The acceleration / deceleration judgment is quickly completed by looking up a table, reducing the amount of real-time hardware computation.

[0025] In addition, by continuously monitoring and processing the received signal data in real time, and repeating steps 2 to 5, the system responds in real time to environmental changes, including changes in communication distance, transceiver angle, and background noise, automatically adjusting the symbol rate level to maintain optimal communication performance. The overall process forms a continuous closed loop: forward link → feedback link → rate adjustment → new round of forward link.

[0026] Based on the above method, this invention also provides a symbol rate adaptive system for an ultraviolet communication system, the system comprising: The rate setting module is used to set the initial symbol rate setting of the ultraviolet communication system according to the communication distance, expected light intensity, or mission scenario. The transmitting module continuously sends data frames at the initial symbol rate level, records the number of frames sent, stops sending when the cumulative number of frames sent reaches a fixed number, and waits for feedback; then it parses the current link's signal photon count rate from the received feedback frames. and background noise photon count rate These two parameters are then input into the rate adaptive control module; The receiving module is used to extract the frame sequence number after receiving any frame, and send a feedback frame to the sending module after waiting for a specified frame interval; wherein, the feedback frame contains channel estimation parameters, namely the signal photon count rate of the current link. and background noise photon count rate ; The rate adaptive control module is used to determine the quality of the current link based on the obtained channel estimation parameters of the current link, and to dynamically adjust and switch the symbol rate according to the channel criteria required by LDPC.

[0027] The specific implementation process of each module in the above system is described in the above method embodiments.

[0028] In practice, the general framework of this symbol rate adaptive system can be extended to other symbol rate adaptive systems in the field of communication, and is not limited to ultraviolet communication systems or communication systems using LDPC coding.

[0029] This invention also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program and the processor is configured to run the computer program to perform the method.

[0030] This invention also provides a computer storage medium storing a plurality of instructions adapted for loading and executing the method by a processor.

[0031] It is worth noting that the contents not described in detail in the embodiments of the present invention belong to the prior art known to those skilled in the art.

[0032] The method described in this invention is illustrated below with a specific example. In this example, both the transceiver and receiver use ultraviolet LEDs to transmit signals and PMTs to receive signals. The experiment was conducted indoors, with the distance between the transmitter and receiver within 30 meters. The transceiver link was an NLOS channel. The improvement and deterioration of channel conditions were simulated by manually controlling the distance between the two ends. The two rate increases and decreases corresponded to the two round trips in which the transceiver and receiver moved closer and then further apart, generating real-time fluctuations in link strength, thereby triggering the symbol rate adaptive mechanism.

[0033] The experiment recorded the changes in the feedback frame number in the embodiments of the present invention. and The changing trend was shown, and a trend chart was drawn, such as... Figure 4 The image shows the link parameters described in an embodiment of the present invention. and A trend graph showing how many feedback frames change, from Figure 4As can be seen, due to the initial short distance between the transmitting and receiving ends, the 25K setting at system startup was too conservative, resulting in... The rate is as high as 122, and it jumps directly to 100K during the first feedback after the system starts up.

[0034] Subsequently, the transmitting and receiving ends gradually approached each other. During the feedback process of the first 35 frames, the rate increased from 100K to 1M. After maintaining this rate for a period of time, the transmitting and receiving ends gradually moved away from each other. During the feedback process from the 73rd to the 96th frame, the rate decreased from 1M to 100K.

[0035] During the feedback process from frame 106 to frame 204, the experimenters gradually moved the transmitter and receiver closer and then further away, increasing the symbol rate from 100K to 1M and then decreasing it to 25K. The rate was maintained at 25K for a period until the feedback in frame 228, at which point the transmitter was moved closer, and the symbol rate returned to 1M.

[0036] The entire experimental process corresponds to Figure 4 The medium speed range fluctuates up and down in a stepped manner, and... The changing trends were completely consistent. A total of 18,249 frames were transmitted in the experiment, with an accuracy rate of 99.7%, which fully verified the effectiveness and stability of the method of the present invention.

[0037] The experimental results above show that the method described in this invention can track link changes in real time, actively reduce speed to ensure reliability when the link deteriorates, and increase speed in time to improve transmission efficiency when the link improves. The overall mechanism is stable, the switching is accurate, there is no cumulative count drift problem, and the use of lookup table judgment greatly reduces the hardware computing pressure.

[0038] In summary, the method and system described in the embodiments of the present invention have the following advantages: 1. The method of the present invention automatically reduces the speed when the link deteriorates, thereby reducing the frame error rate; and automatically increases the speed when the link is good, so that the communication rate is always close to the available upper limit. The overall mechanism is stable, the switching is accurate, and there is no cumulative count drift problem. 2. The method of the present invention can respond in real time to changes in environmental conditions, such as light intensity and meteorological factors, to ensure that the optimal communication rate can be selected under different environments and to improve communication quality. 3. The method proposed in this invention uses a lookup table approach to replace complex calculations, which greatly reduces the real-time computing pressure on the FPGA, and the speed level can be flexibly configured according to the application scenario.

[0039] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. The information disclosed in the background section is intended only to enhance the understanding of the overall background technology of the present invention and should not be construed as an admission or implication in any way that such information constitutes prior art known to those skilled in the art.

Claims

1. A symbol rate adaptive method for an ultraviolet communication system, characterized in that, The method includes: Step 1: Set the initial symbol rate setting of the ultraviolet communication system according to the communication distance, expected light intensity, or mission scenario; Step 2: The sending end continuously sends data frames at the initial symbol rate setting, records the number of frames sent, and stops sending when the cumulative number of frames sent reaches a fixed number, and waits for feedback; Step 3: After receiving any frame, the receiving end extracts the frame sequence number and sends a feedback frame to the sending end after waiting for a specified frame interval; wherein, the feedback frame contains channel estimation parameters, namely the signal photon count rate of the current link. and background noise photon count rate ; Step 4: The transmitting end parses the current link's signal photon count rate from the received feedback frame. and background noise photon count rate These two parameters are then input into the rate adaptive control module; Step 5: The rate adaptive control module determines the quality of the current link based on the obtained channel estimation parameters of the current link, and performs dynamic adjustment and switching of the symbol rate according to the channel criteria required by the low-density parity-check code (LDPC).

2. The symbol rate adaptive method for an ultraviolet communication system according to claim 1, characterized in that, In step 1, the symbol rate settings include: {25K, 100K, 250K, 500K, 1M}; The above symbol rate settings are pre-configured by the system and can be flexibly expanded according to the hardware platform capabilities and protocol requirements.

3. The symbol rate adaptive method for the ultraviolet communication system according to claim 1, characterized in that, In step 3, to ensure the correctness of the feedback trigger position, the first 8 bits of the L-bit valid information of each frame of data sent by the sending end are the frame sequence number field, which is used to identify the relative position of the frame of data in a fixed frame number period. The receiving end only needs to correctly receive any frame to parse the frame number x in the current period, and according to the known transmission period pattern, send the corresponding feedback frame after a delay of a fixed number of frames - x frames. In the L-bit valid information of the feedback frame, the first 32 bits are the channel estimation parameters. and The other structures are similar to those of the sent frame.

4. The symbol rate adaptive method for the ultraviolet communication system according to claim 1, characterized in that, In step 5, the dynamic adjustment and switching process of the symbol rate is as follows: Speed ​​reduction judgment: If the link quality degrades to the current background noise photon count rate Under the given conditions, the current signal photon count rate If the value falls below the switching boundary condition, the symbol rate is reduced by one level; the switching boundary condition is determined by applying different values ​​under fixed symbol rate and sampling conditions. The scenario was obtained through multiple independent random trials, and the minimum value that could reliably achieve decoding was selected. The value is increased by a fixed value of 10 as the boundary point under the background conditions; Acceleration determination: If the current and At the same time, the corresponding multiplier is reduced, that is, the ratio of the higher speed setting to the current speed, after reducing the multiplier. If it is still higher than the switching boundary condition, the rate will be increased by one level; If the current and If neither the deceleration nor acceleration conditions are met, the speed remains constant.

5. The symbol rate adaptive method for an ultraviolet communication system according to claim 4, characterized in that, The switching boundary conditions are obtained through LDPC bit error rate simulation and pre-written into the storage unit. The acceleration / deceleration judgment is quickly completed by looking up a table.

6. The symbol rate adaptive method for an ultraviolet communication system according to claim 1, characterized in that, The method also includes continuously monitoring and processing the received signal data in real time, repeating the operations of steps 2 to 5, responding in real time to environmental changes, including changes in communication distance, changes in the angle of the transmitting and receiving ends, and changes in background noise, and automatically adjusting the symbol rate level.

7. The symbol rate adaptive method for an ultraviolet communication system according to claim 1, characterized in that, In the forward link data frames sent in step 2, each frame contains LDPC encoding information, a frame sequence number field, and a CRC checksum to ensure the stable operation of the forward link and the feedback link.

8. A symbol rate adaptive system for an ultraviolet communication system, characterized in that, The system includes: The rate setting module is used to set the initial symbol rate setting of the ultraviolet communication system according to the communication distance, expected light intensity, or mission scenario. The transmitting module continuously sends data frames at the initial symbol rate level, records the number of frames sent, stops sending when the cumulative number of frames sent reaches a fixed number, and waits for feedback; then it parses the current link's signal photon count rate from the received feedback frames. and background noise photon count rate These two parameters are then input into the rate adaptive control module; The receiving module is used to extract the frame sequence number after receiving any frame, and send a feedback frame to the sending module after waiting for a specified frame interval; wherein, the feedback frame contains channel estimation parameters, namely the signal photon count rate of the current link. and background noise photon count rate ; The rate adaptive control module is used to determine the quality of the current link based on the obtained channel estimation parameters of the current link, and to dynamically adjust and switch the symbol rate according to the channel criteria required by LDPC.

9. An electronic device comprising a memory and a processor, characterized in that, The memory stores a computer program, and the processor is configured to run the computer program to perform the method according to any one of claims 1 to 7.

10. A computer storage medium, characterized in that, The computer storage medium stores a plurality of instructions adapted for loading by a processor and executing the method of any one of claims 1 to 7.

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