Design method of physical frame structure suitable for high-order high-rate wireless communication between satellite and ground

Abstract

The application provides a physical frame structure design method suitable for high-order high-code-rate satellite-ground wireless communication, comprising the following steps: slicing service data according to a preset length to generate a baseband frame; performing scrambling processing on the baseband frame to obtain a scrambled baseband frame; performing preset error correction coding processing on the scrambled baseband frame in sequence to obtain a coding frame; performing inner interleaving processing on the coding frame to obtain inner interleaving data and form a first physical frame; performing outer interleaving processing on the first physical frame to obtain outer interleaving data; mapping the outer interleaving data into a symbol stream; performing physical frame framing based on the symbol stream to obtain a second physical frame; performing scrambling processing on the to-be-scrambled symbols in the second physical frame except for a physical frame header to obtain a scrambled physical frame; and performing modulation based on the scrambled physical frame to transmit data, so that the anti-phase noise capability, the anti-channel distortion capability, the anti-Doppler frequency shift performance, the transmission efficiency and the reliability are improved.

Description

Technical Field

[0001] This invention relates to the field of satellite communication technology, and in particular to a physical frame structure design method suitable for high-order, high-code-rate wireless communication between satellite and ground. Background Technology

[0002] In recent years, with the rapid development of satellite communication technology, its evolution towards higher bandwidth and capacity has become increasingly significant. In satellite communication systems such as direct satellite connections for mobile phones, hybrid multiple access methods such as frequency division, time division, and space division are often used to achieve wide-area, high-density access in order to improve user-side capacity. However, feeder links are limited by the construction costs of ground gateway stations, and spatial reuse methods are also limited. Therefore, they mainly rely on increasing transmission bandwidth and efficiency to enhance link capabilities. With the accelerated deployment of my country's GW and Qianfan constellations, improving feeder link rates is of great significance to the overall constellation performance.

[0003] In the field of space exploration, the significant increase in the number and resolution of satellite payloads has led to a geometric increase in data volume, creating an urgent need for high-speed satellite-to-ground data transmission. The contradiction between the demand for satellite data downlink and the insufficient bandwidth of satellite-to-ground transmission has become a core issue restricting the effectiveness of satellites.

[0004] The main technical means to improve satellite-to-ground transmission rates include: using higher frequency bands (such as the W band) to expand communication bandwidth; achieving high-speed transmission at hundreds of Gbps through optoelectronic coordination combined with laser links, and using microwave links to ensure all-weather backup; and combining high-order modulation schemes with VCM / ACM technology to improve frequency efficiency and transmission rate. Among these, high-order modulation schemes are considered the most promising solution due to their speed and cost-effectiveness.

[0005] However, high-order modulation schemes are not yet widely used in my country's on-orbit satellite-to-ground data transmission projects. This is mainly due to the high peak-to-average power ratio (PAPR) caused by high-order modulation, the phase sensitivity resulting from dense constellation points, and the significant impact of various distortions on reception performance. Existing satellite-to-ground data transmission standards, such as CCSDS and DVB-S2, are limited by their frame structure, interleaving methods, and modulation orders, making them unsuitable for the demands of high-order, high-code-rate satellite communication.

[0006] Therefore, a novel physical frame structure design is urgently needed to address the distortion problems associated with high-bit-rate signal transmission, in order to improve the engineering application level of high-order high-speed satellite-to-ground communication and overcome the shortcomings of existing technologies in terms of reliability, efficiency, and adaptability. Summary of the Invention

[0007] This invention provides a physical frame structure design method suitable for high-order, high-code-rate satellite-to-ground wireless communication, which improves phase noise resistance, optimizes transmission efficiency, and enhances adaptability to complex environments.

[0008] On one hand, the present invention provides a physical frame structure design method suitable for high-order, high-code-rate satellite-to-ground wireless communication, which includes:

[0009] The business data is sliced ​​according to a preset length, and a baseband frame is generated based on the obtained data slices;

[0010] The baseband frame is scrambled to obtain a scrambled baseband frame; wherein the baseband frame includes a frame header, a data area, and a check area;

[0011] The scrambled baseband frames are sequentially subjected to preset error correction coding processes to obtain coded frames;

[0012] The encoded frame is subjected to internal interleaving to obtain internally interleaved data, which is then used to form the first physical frame;

[0013] The first physical frame is subjected to external interleaving processing to obtain externally interleaved data;

[0014] The externally interleaved data is mapped into a symbol stream; wherein the symbol stream employs a preset high-order modulation scheme;

[0015] The physical frame is assembled based on the symbol stream to obtain a second physical frame; wherein, the physical frame assembly includes inserting pilot blocks at preset intervals and adding a physical frame header;

[0016] Scrambling is performed on the symbols to be scrambled in the second physical frame, excluding the physical frame header, to obtain a scrambled physical frame, which is then used for modulation and data transmission.

[0017] According to the present invention, a physical frame structure design method for high-order, high-code-rate satellite-to-ground wireless communication is provided, which performs physical frame assembly based on the symbol stream to obtain a second physical frame, including:

[0018] The spreading factor of the symbol stream is determined based on the signal-to-noise ratio of the satellite-to-ground wireless channel;

[0019] The symbol stream is spread according to the spreading factor to obtain a spread spectrum symbol stream;

[0020] The physical frame header is added to the spread spectrum symbol stream, and the pilot blocks are inserted at preset intervals.

[0021] The physical frame structure design method for high-order, high-code-rate satellite-to-ground wireless communication provided by the present invention further includes:

[0022] Obtain the performance parameters of the satellite-to-ground wireless channel; the performance parameters include at least one of the following: received signal-to-noise ratio, received power intensity, received power variation, transmitted power, and Doppler.

[0023] Based on the performance parameters, the satellite-to-ground communication scenario is determined; the satellite-to-ground communication scenario includes at least one of the following: clear sky high elevation angle scenario, conventional medium and low elevation angle scenario, and rain-affected signal scenario;

[0024] Based on the satellite-to-ground communication scenario and the pre-built constraint model, the number of interleaved data, the length of the preset interval, and the length of the pilot block are determined.

[0025] According to the present invention, a physical frame structure design method for high-order, high-code-rate satellite-to-ground wireless communication is provided, which determines the number of interleaved data, the length of the preset interval, and the length of the pilot block based on the satellite-to-ground communication scenario and a pre-built constraint model, including:

[0026] Based on the described satellite-to-ground communication scenario, determine the constraint priority;

[0027] Based on the constraint priority, determine the candidate value ranges for the number of interleaved data, the length of the preset interval, and the length of the pilot block;

[0028] Based on their respective candidate value ranges, each candidate value is selected as its current candidate value, and iterative verification is performed based on the constraint model until each candidate value satisfies all constraints of the constraint model, thereby obtaining the number of interleaved data, the length of the preset interval, and the length of the pilot block.

[0029] According to the present invention, a physical frame structure design method for high-order high-code-rate satellite-to-ground wireless communication is provided, wherein the constraint model includes delay constraints and overhead constraints.

[0030] The delay constraint is that the ratio of the total length of the second physical frame to the scene coefficient of different satellite-to-ground communication scenarios is less than a preset duration;

[0031] The overhead constraint is that the ratio of the total length of the pilot to the total length of the second physical frame is less than a preset overhead value;

[0032] The total length of the second physical frame is the sum of the length of the physical frame header, the length of all pilot blocks, and the length of the spread spectrum symbol stream.

[0033] The physical frame structure design method for high-order, high-code-rate satellite-to-ground wireless communication provided by the present invention further includes:

[0034] The combination parameters of the higher-order modulation scheme and error correction coding scheme are adaptively adjusted based on the signal-to-noise ratio of the satellite-to-ground wireless channel.

[0035] According to the present invention, a physical frame structure design method for high-order, high-code-rate satellite-to-ground wireless communication adaptively adjusts the combination parameters of the high-order modulation scheme and the error correction coding scheme based on the signal-to-noise ratio of the satellite-to-ground wireless channel, including:

[0036] When the signal-to-noise ratio is less than the lower threshold, the pre-constructed combined parameter label is decremented by 1; when the signal-to-noise ratio is greater than the upper threshold, the combined parameter label is incremented by 1.

[0037] The combination parameter labels are the labels of the combination parameters of different higher-order modulation methods and error correction coding methods arranged in sequence.

[0038] According to the present invention, a physical frame structure design method suitable for high-order high-code-rate satellite-to-ground wireless communication is provided, which performs scrambling processing on the symbols to be scrambled in the second physical frame, excluding the physical frame header, including:

[0039] Energy randomization is achieved by multiplying the sampling points of the symbols to be scrambled in the second physical frame by a complex random sequence; wherein, the rate of the complex random sequence is consistent with the symbol rate of the physical frame, and the complex random sequence is reset at the end of each physical frame header; the complex random sequence consists of two real m-sequences, which are generated by 18th-order prototype polynomials respectively, ultimately forming fragments of Gold code, and the two prototype polynomials are preset as follows: and .

[0040] According to the present invention, a physical frame structure design method suitable for high-order high-code-rate satellite-to-ground wireless communication is provided, wherein the physical frame header includes synchronization bits, signaling bits, and reserved bits;

[0041] The method further includes:

[0042] Determine the length of the synchronization bit based on the signal-to-noise ratio of the channel;

[0043] Select the default length to obtain the length of the signaling bits;

[0044] The length of the reserved bits is determined based on the functional expansion requirements.

[0045] According to the present invention, a physical frame structure design method suitable for high-order high-code-rate satellite-to-ground wireless communication is provided, wherein the internal interleaving process adopts an N×M rectangular interleaving structure to adapt to the coding characteristics of the coded frame;

[0046] The external interleaving process employs convolutional interleaving to reduce data processing latency.

[0047] This invention provides a physical frame structure design method for high-order, high-code-rate satellite-to-ground wireless communication. The method involves segmenting and filling input service data according to a preset slice length to form standard-length data slices; inserting a customizable baseband frame header into these data slices to generate a baseband frame consisting of a frame header, data area, and checksum area; scrambling the baseband frame to reduce peak-to-average power ratio and improve transmission security; performing forward error correction coding on the scrambled baseband frame to generate a coded frame; implementing internal interleaving on the coded frame to resist burst errors; further external interleaving the internally interleaved data to form a first physical frame, enhancing resistance to long burst errors; and mapping the interleaved data into a symbol stream using high-order modulation. It supports various modulation schemes from QPSK to 256QAM; it inserts pilot blocks at set intervals and adds physical frame headers to the symbol stream to complete physical frame assembly, forming a second physical frame; it scrambles and randomizes the energy of the data symbols in the second physical frame to generate the final scrambled physical frame for modulation and wireless transmission. In this way, by constructing a physical frame structure that includes multiple interleaving processes, adaptive modulation coding, and dynamic pilot insertion, and by adopting staged scrambling and energy randomization techniques, it effectively solves the technical problems of high phase sensitivity and weak anti-distortion ability under high-order modulation schemes, thereby improving the anti-phase noise capability, anti-channel distortion capability, enhancing anti-Doppler frequency shift performance, and optimizing transmission efficiency and reliability. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0049] Figure 1 This is a flowchart illustrating the physical frame structure design method for high-order, high-code-rate satellite-to-ground wireless communication provided in an embodiment of the present invention.

[0050] Figure 2 This is a schematic diagram of the physical frame structure. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0052] In existing technologies, satellite communication technology faces the challenge of limited application of high-order modulation schemes. The frame structure design used in traditional satellite-to-ground data transmission standards is difficult to adapt to the requirements of high-order, high-bit-rate transmission, exhibiting problems such as high phase sensitivity and weak distortion resistance. For example, the interleaving method in existing frame structures cannot effectively cope with interference from dense constellation points, leading to increased bit error rate in complex channel environments. Furthermore, the fixed-length physical frame structure lacks flexibility, failing to dynamically adjust parameters according to different channel conditions, thus limiting the improvement of transmission efficiency.

[0053] To address the aforementioned issues, a physical frame structure that is compatible with high-order modulation and enhances anti-interference capabilities is needed. Existing technologies using separate interleaving and error correction coding designs result in increased processing time, while fixed pilot insertion intervals struggle to balance overhead and synchronization performance. Analysis reveals that combining internal and external interleaving optimizes the data processing flow, and dynamically adjusting pilot density adapts to different channel environments. Furthermore, implementing symbol-level scrambling outside the physical frame header can reduce signal energy concentration and improve anti-interception capabilities.

[0054] Therefore, this invention proposes a technical solution to generate baseband frames by slicing service data into slices of a preset length, performing error correction coding on the baseband frames after scrambling to form coded frames and performing internal interleaving to obtain the first physical frame; performing symbol mapping on the externally interleaved data and generating a symbol stream using a higher-order modulation method; inserting pilot blocks and adding physical frame headers during the physical frame assembly process, and performing scrambling on the symbols outside the frame header to form the final physical frame.

[0055] Specifically, Figure 1 This is a flowchart illustrating the physical frame structure design method for high-order, high-code-rate wireless communication between satellite and ground, provided by an embodiment of the present invention.

[0056] like Figure 1 As shown, the physical frame structure design method for high-order, high-code-rate satellite-to-ground wireless communication provided in this embodiment of the invention can be implemented by an electronic device. The method mainly includes the following steps:

[0057] 101. Slice the business data into segments of a preset length and generate baseband frames based on the obtained data segments;

[0058] 102. Perform scrambling processing on the baseband frame to obtain a scrambled baseband frame; wherein the baseband frame includes a frame header, a data area, and a check area;

[0059] 103. Perform preset error correction coding processing on the scrambled baseband frames sequentially to obtain coded frames;

[0060] 104. Perform internal interleaving processing on the encoded frame to obtain internally interleaved data and form the first physical frame;

[0061] 105. Perform external interleaving processing on the first physical frame to obtain externally interleaved data;

[0062] 106. Map the externally interleaved data into a symbol stream; wherein the symbol stream employs a preset high-order modulation scheme;

[0063] 107. Perform physical frame assembly based on the symbol stream to obtain a second physical frame; wherein, physical frame assembly includes inserting pilot blocks at preset intervals and adding a physical frame header;

[0064] 108. Perform scrambling processing on the symbols to be scrambled in the second physical frame, excluding the physical frame header, to obtain a scrambled physical frame, and then perform data transmission based on modulation of the scrambled physical frame.

[0065] Data slicing refers to dividing service data into fixed-length data units that meet coding requirements. This can be achieved using a preset threshold comparison and padding mechanism to ensure the processing efficiency of subsequent coding modules. Baseband frame scrambling involves randomizing the energy of transmitted data using a pseudo-random sequence. This can be achieved using a scrambling code sequence generated by a linear feedback shift register to effectively suppress interference from specific spectral components. Inner interleaving involves matrix rearranging and reassembling the coded data. This can be achieved using an N×M rectangular interleaver to disperse burst errors in the channel. Outer interleaving involves reassembling data across multiple coded frames. This can be achieved using a convolutional interleaving structure to reduce system processing latency. Symbol stream mapping involves converting the bit stream into complex modulation symbols. This can be achieved using a high-order modulation constellation diagram with Gray coding to improve bandwidth utilization. Physical frame assembly involves constructing a complete transmission unit by inserting pilot blocks and adding frame headers. This can be achieved using a variable-interval pilot insertion strategy to assist in channel estimation at the receiver.

[0066] Specifically, business data is segmented into baseband data units after length adaptive slicing, and data correlation is eliminated through scrambling. Forward error correction coding is used to enhance resistance to random errors, and internal interleaving is used to disperse the distribution of burst errors. Multiple coded frames are convolutionally interleaved to reduce transmission delay. After being mapped to higher-order modulation symbols, periodic pilot blocks are inserted into the physical frame for channel estimation and phase noise compensation. A frame header containing synchronization and signaling information is added to ensure correct parsing at the receiver. Finally, the data symbols undergo secondary scrambling to avoid spectrum leakage. Each processing stage is dynamically configured to adapt to different channel conditions, forming a complete anti-interference transmission system. The physical frame header includes synchronization bits, signaling bits, and reserved bits, which can be designed to support signaling scrambling or not. If signaling scrambling is required, scrambling begins at the signaling bit; if signaling is not scrambling, scrambling begins at the reserved bits.

[0067] This invention employs a dual-interleaving structure to process encoded data and physical frame data separately, reducing latency while enhancing resistance to burst errors. Combining the synergistic effects of rectangular interleaving and convolutional interleaving, it maintains high coding gain while reducing processing latency. Compared to a fixed-interval design, the dynamic pilot insertion mechanism automatically optimizes pilot density based on channel coherence time, significantly improving the demodulation reliability of high-order modulated signals.

[0068] Through the above technical solution, this invention effectively solves the phase sensitivity problem of high-order modulated signals in satellite-to-ground channels. It enhances the resistance to sudden interference through a double-interleaving structure and compensates for channel estimation errors using a pilot insertion strategy, thus achieving stable transmission of high-order, high-code-rate signals. This solution maintains high spectral efficiency while possessing the flexibility to adapt to changes in the channel environment, significantly improving the reliability of communication links under complex weather conditions.

[0069] In some embodiments, the present invention further proposes to determine the spreading factor of the symbol stream based on the signal-to-noise ratio of the satellite-to-ground wireless channel, spread the symbol stream according to the spreading factor to obtain a spread spectrum symbol stream, add a physical frame header to the spread spectrum symbol stream and insert pilot blocks at preset intervals.

[0070] The spreading factor refers to the signal spreading ratio dynamically adjusted based on the real-time measured signal-to-noise ratio (SNR) of the satellite-to-ground channel. This can be achieved using a lookup table method or an adaptive algorithm, balancing anti-interference capability and spectral efficiency by matching channel conditions. The spreading symbol stream is a redundant signal sequence generated by repeating or extending symbol periods. This can be implemented using direct sequence spreading or orthogonal code division multiple access (OCD) techniques to improve signal acquisition probability in low SNR environments. The physical frame header is a fixed-format data segment containing synchronization sequences and signaling information. This can be implemented using a pseudo-random sequence as synchronization bits combined with forward error correction coding in the signaling field, used for physical layer frame synchronization and parameter transfer. The pilot block is a periodically inserted sequence of known reference signals. This can be implemented using a constant envelope zero autocorrelation sequence or an orthogonal frequency division multiplexing (OFDM) pilot structure, used for channel estimation and phase noise compensation.

[0071] Specifically, during the physical frame assembly process, the current signal-to-noise ratio (SNR) measurement is first obtained by real-time monitoring of link quality, and the optimal spreading parameters are determined according to the preset SNR-spreading factor mapping relationship. Then, a symbol-level copying and spreading operation is performed on the symbol stream to generate a spread spectrum symbol sequence with time diversity gain. A physical frame header containing synchronization headers and modulation / coding information is inserted at the beginning of the spread symbol stream, and pilot symbol blocks are embedded in the data symbol segments at fixed periods, forming a frame structure with channel estimation capabilities.

[0072] This invention solves the problem of low resource utilization caused by fixed spread spectrum mode by establishing a dynamic correlation mechanism between signal-to-noise ratio and spreading parameters, which automatically enhances signal redundancy to improve reliability under poor channel conditions and reduces redundancy to improve spectrum efficiency under good channel conditions.

[0073] Through the above technical solution, the present invention realizes adaptive transmission optimization of the satellite-to-ground communication link in complex propagation environments, effectively improving the channel resource utilization rate while ensuring signal reliability. It is particularly suitable for high-dynamic satellite communication scenarios with interference such as atmospheric attenuation and Doppler shift.

[0074] In some embodiments, the present invention further proposes a physical frame structure design method suitable for high-order, high-code-rate satellite-to-ground wireless communication, including obtaining performance parameters of the satellite-to-ground wireless channel; the performance parameters include at least one of received signal-to-noise ratio, received power intensity, received power variation, transmitted power, and Doppler; determining the satellite-to-ground communication scenario based on the performance parameters; the satellite-to-ground communication scenario includes at least one of clear sky high elevation angle scenario, conventional medium-low elevation angle scenario, and rain-attenuated signal scenario; and determining the number of internally interleaved data, the length of the preset interval, and the length of the pilot block based on the satellite-to-ground communication scenario and a pre-built constraint model.

[0075] Among them, performance parameters refer to a set of indicators characterizing channel transmission quality. Specifically, they can be implemented using at least one of the following parameters collected in real time by the channel measurement module: received signal-to-noise ratio, received power intensity, received power variation, transmitted power, and Doppler. These parameters are used to quantitatively evaluate the stability of the channel under different interference conditions. Satellite-to-ground communication scenarios refer to typical working environments classified according to channel characteristics. This can be implemented by establishing a scenario classification decision tree, categorizing scenarios with phase noise suppression capabilities below a threshold as rain-attenuated scenarios. The constraint model refers to a mathematical relationship containing delay and overhead constraints. This can be implemented using a multi-objective optimization algorithm, setting the ratio of total frame length to scenario coefficients as delay constraints and the pilot overhead ratio as overhead constraints to form the boundary conditions for parameter selection.

[0076] Specifically, during channel transmission, the system monitors phase noise suppression capabilities in real time to determine if the system is in a rain-attenuation scenario severely affected by atmospheric turbulence, and identifies ionospheric disturbance scenarios unique to polar regions based on anti-Doppler capabilities. To address the channel stability characteristics under clear, high-elevation-angle scenarios, the constraint model prioritizes a larger number of internal interleavings to improve error correction capabilities. In rain-attenuation scenarios, the channel estimation accuracy is enhanced by shortening the pilot interval length. By establishing a multi-dimensional optimization space that includes delay and overhead constraints, an iterative algorithm searches for the optimal parameter combination that satisfies all constraints within the candidate value range. For example, in typical low-to-medium elevation-angle scenarios, the pilot block length can be set to 16 symbols, the interval length to 480 symbols, and the number of internal interleavings to 8 groups.

[0077] Compared to existing technologies, traditional methods use fixed-length pilot spacing and interleaving depth, making it impossible to adjust parameter configurations according to the dynamic characteristics of the channel. Existing technologies lack a mapping relationship between scene classification and parameter selection, which can easily lead to wasted pilot resources or insufficient channel estimation accuracy under extreme weather conditions. This invention, by constructing a scene-adaptive constraint model, achieves dynamic matching between transmission parameters and channel states, overcoming the performance bottleneck of single-parameter configuration in different environments.

[0078] Through the above technical solution, this invention can automatically optimize key transmission parameters based on real-time channel characteristics. In rain-attenuation scenarios, it improves signal demodulation accuracy by shortening the pilot interval, and in polar scenarios, it enhances resistance to sudden interference by increasing the internal interleaving depth. This solution effectively solves the adaptability problem of high-order modulation schemes in different channel environments, significantly improving system robustness while ensuring transmission efficiency.

[0079] In some embodiments, the present invention further proposes determining the number of interleaved data, the length of the preset interval, and the length of the pilot block based on the satellite-to-ground communication scenario and a pre-built constraint model, including: determining the constraint priority based on the satellite-to-ground communication scenario; determining the candidate value ranges for the number of interleaved data, the length of the preset interval, and the length of the pilot block based on the constraint priority; selecting the current candidate value based on the candidate value range, and performing iterative verification based on the constraint model until the current candidate value satisfies all constraints of the constraint model, thereby obtaining the number of interleaved data, the length of the preset interval, and the length of the pilot block.

[0080] Among them, constraint priority refers to the ranking of optimization targets for latency, overhead, and anti-interference capability under different satellite-to-ground communication scenarios. Specifically, it can be achieved by mapping scenario feature parameters to a priority weight matrix. For example, overhead constraints are given priority in clear weather high elevation angle scenarios, while latency constraints are given priority in rainy and weak attenuation scenarios.

[0081] The candidate value range refers to the range of values ​​allowed for the number of interleavings, pilot spacing, and pilot block length in a specific scenario. Specifically, it can be generated through a model that associates channel characteristics with frame structure parameters. For example, the maximum and minimum values ​​of the pilot spacing can be calculated based on the Doppler frequency shift range.

[0082] Iterative verification refers to the process of cyclically adjusting the combination of candidate parameters and evaluating whether the constraints are met. Specifically, it can be implemented using Monte Carlo simulation or fast convergence algorithms. For example, the pilot interval step size can be adjusted to an integer multiple of the symbol length in each iteration.

[0083] The constraint model includes delay constraints and overhead constraints, which are specifically defined by establishing a correlation function between the total physical frame length and the scene coefficient, and a pilot overhead ratio threshold function. For example, the delay constraint is transformed into a ratio between the frame length and the channel coherence time.

[0084] Specifically, a constraint priority mapping table is established for different satellite-to-ground communication scenarios. For example, the phase noise suppression requirement for rain-attenuated signal scenarios is set as the highest priority. Candidate ranges are defined based on priority for the number of interleavings, pilot spacing, and pilot block length. For example, in typical low-to-medium elevation angle scenarios, the candidate value for pilot spacing is 480 to 960 symbols. A parameter combination generation module generates a set of candidate values, and a constraint verification module performs dual verification of latency and overhead for each candidate combination. When a candidate combination cannot simultaneously satisfy both constraints, the secondary constraint is relaxed according to priority order. For example, in rain-attenuated scenarios, latency constraints are prioritized, allowing pilot overhead to slightly exceed a preset threshold. The iterative process continues until the optimal parameter combination that satisfies all constraints is obtained, ultimately outputting the number of interleavings, pilot spacing, and pilot block length adapted to the current scenario.

[0085] This invention solves the problem of poor parameter adaptability of traditional methods in complex channel environments by establishing a multi-constraint joint optimization mechanism and introducing a scenario-driven priority strategy in the parameter selection process.

[0086] Through the above technical solution, this invention achieves dynamic optimization configuration of physical frame parameters for satellite-to-ground communication in different scenarios, effectively balancing the contradiction between latency and overhead while ensuring transmission reliability. For example, in rain-attenuated scenarios, the anti-interference capability is improved by shortening the pilot interval, while controlling the total frame length to avoid exceeding the latency threshold; in clear-sky high-elevation-angle scenarios, the overhead is reduced by increasing the pilot interval, thereby improving the effective data transmission efficiency. This parameter optimization method based on a constraint model overcomes the limitations of traditional fixed parameter configuration, enabling the physical frame structure to adapt to the complex and ever-changing satellite-to-ground communication environment.

[0087] In some embodiments, the present invention further proposes a constraint model including a delay constraint and an overhead constraint; the delay constraint is that the ratio of the total length of the second physical frame to the scenario coefficient of different satellite-to-ground communication scenarios is less than a preset duration; the overhead constraint is that the ratio of the total length of the pilot to the total length of the second physical frame is less than a preset overhead value; wherein, the total length of the second physical frame is the sum of the length of the physical frame header, the length of all pilot blocks, and the length of the spread spectrum symbol stream.

[0088] Among them, the delay constraint refers to ensuring that the transmission delay in different communication scenarios meets the preset requirements by limiting the ratio between the physical frame length and the scenario coefficient. Specifically, it can be achieved by dynamically adjusting the physical frame length or the scenario coefficient. The scenario coefficient can be set based on channel characteristics or environmental factors.

[0089] Among them, overhead constraint refers to ensuring effective data transmission efficiency by limiting the proportion of pilot resources in the physical frame. Specifically, it can be achieved by adaptively adjusting the length or interval of the pilot block. The total length of the pilot can be optimized based on the channel estimation accuracy requirements.

[0090] The total length of the second physical frame consists of three parts: the physical frame header, the pilot block, and the spread spectrum symbol stream. Specifically, it can be calculated by superimposing the number of symbols in each part. The length of the physical frame header and the length of the pilot block can be dynamically adjusted according to the synchronization performance requirements and channel conditions.

[0091] Specifically, in satellite-to-ground communication, for different scenarios such as high elevation angles in clear weather and weak signals in rain, a constraint model is used to jointly optimize latency and overhead. For example, in the rain-attenuated scenario, the scenario coefficient can be set to a smaller value to reduce the latency constraint threshold, while the pilot block length is increased to improve channel estimation accuracy. At this time, parameters such as the number of interleaved data and pilot spacing are determined through iterative verification to ensure that both latency and overhead constraints are met.

[0092] Compared to existing technologies, traditional satellite-to-ground communication frame structures typically employ fixed pilot intervals and frame lengths, failing to dynamically balance latency and resource overhead based on the scenario. For example, the current DVB-S2 standard uses a fixed interval for pilot insertion, resulting in insufficient pilot resources in low signal-to-noise ratio (SNR) scenarios and resource waste in high SNR scenarios. This invention establishes a joint constraint model for latency and overhead, achieving dynamic parameter adaptation. This avoids exceeding transmission latency limits while optimizing pilot resource utilization.

[0093] Through the above technical solution, this invention can dynamically adjust the physical frame structure parameters for different satellite-to-ground communication scenarios, maximizing the effective data ratio while meeting transmission delay requirements. For example, in conventional low-to-medium elevation angle scenarios, by reducing the pilot block length and increasing the spread spectrum symbol stream ratio, data transmission efficiency can be improved while ensuring channel estimation accuracy; in rain-attenuated scenarios, by increasing the pilot block length and shortening the spread spectrum symbol stream, the system's anti-interference capability can be enhanced. This solves the problems of low resource utilization and poor scenario adaptability caused by rigid frame structures in existing technologies.

[0094] In some embodiments, the present invention further proposes to adaptively adjust the combination parameters of the higher-order modulation scheme and the error correction coding scheme according to the signal-to-noise ratio of the satellite-to-ground wireless channel.

[0095] Among them, high-order modulation schemes refer to modulation techniques that improve spectral efficiency by increasing the number of bits carried per symbol. Specifically, they can be implemented using QPSK, 8PSK, 16QAM, 32QAM, 64QAM, 128QAM, or 256QAM, with different orders corresponding to different performance and transmission efficiencies. Error correction coding schemes refer to coding techniques that achieve error detection and correction by adding redundant information, specifically using LDPC codes. Different code rates correspond to different error correction capabilities and coding efficiencies. Combination parameters refer to the pre-defined matching relationship between high-order modulation schemes and error correction coding schemes. These can be sorted using labels, with higher labels representing higher modulation orders and higher code rates. Adaptive adjustment refers to dynamically switching combination parameters based on real-time channel conditions. This can be achieved by setting upper and lower signal-to-noise ratio thresholds to trigger label increases or decreases, thereby maintaining link stability when channel quality fluctuates.

[0096] Specifically, when the signal-to-noise ratio (SNR) of the satellite-to-ground wireless channel is lower than a preset lower threshold, the combination parameter index is decremented by 1 to switch to a low-order modulation and low-code-rate coding combination, reducing the transmission rate but improving noise immunity. When the SNR is higher than a preset upper threshold, the combination parameter index is incremented by 1 to switch to a high-order modulation and high-code-rate coding combination, increasing the transmission rate while keeping the bit error rate within an acceptable range. The combination parameter index is dynamically adjusted according to channel quality, forming a closed-loop control mechanism that ensures the modulation and coding scheme always matches the current channel conditions.

[0097] The combination parameter label refers to the index sequence formed by sorting multiple modulation and coding combinations according to transmission efficiency and anti-interference capability. This can be implemented using numerical numbering; for example, a combination of QPSK and low-rate LDPC coding is labeled as 1, and a combination of 256QAM and high-rate LDPC coding is labeled as 10. Adjusting the number of labels allows for the linkage adjustment of modulation order and error correction strength. Higher-order modulation methods refer to modulation techniques that improve spectral efficiency by increasing constellation point density. These can be implemented using QPSK, 16QAM, 64QAM, etc. For example, 256QAM carries 8 bits of data per symbol. Error correction coding methods refer to coding methods that correct errors by adding redundant information. These can be implemented using LDPC codes, Turbo codes, etc. For example, LDPC coding with a code rate of 0.8 can improve coding gain by approximately 2dB. The signal-to-noise ratio (SNR) is the ratio of received signal power to noise power, which can be achieved through pilot symbol measurement, for example, by inserting a known pilot sequence into the physical frame for channel quality estimation.

[0098] Specifically, during satellite-to-ground communication, the receiver continuously measures the channel signal-to-noise ratio (SNR) and feeds it back to the transmitter. When the measured SNR falls below a preset lower threshold, indicating deteriorating channel conditions, the system decrements the currently used combination parameter label by 1 and switches to a combination of low-order modulation and strong error correction coding. When the SNR exceeds a preset upper threshold, indicating improved channel quality, the system increments the label by 1 and switches to a combination of high-order modulation and high-code-rate coding. For example, in a clear, high-elevation scenario, the system can automatically use a 256QAM modulation combination with a 0.9 code rate LDPC coding combination, while in a rain-attenuated scenario, it switches to a 16QAM modulation combination with a 0.5 code rate LDPC coding combination. A hysteresis interval is set during the label adjustment process to avoid frequent switching caused by short-term fluctuations in the SNR.

[0099] Table 1 lists the combined parameters (MODCOD) of different higher-order modulation and error correction coding methods in order:

[0100] Table 1

[0101]

[0102] This invention solves the performance loss problem caused by fixed combinations by monitoring the signal-to-noise ratio in real time and adaptively switching the combination parameters, while avoiding the lag of manual intervention.

[0103] Through the above technical solution, the present invention realizes dynamic optimization of the satellite-to-ground wireless communication link under time-varying channel conditions, which not only ensures the transmission reliability in low signal-to-noise ratio scenarios, but also makes full use of the channel capacity in high signal-to-noise ratio scenarios, significantly improving the system throughput and robustness.

[0104] In some embodiments, the present invention further proposes a method for performing scrambling processing on the symbols to be scrambled in the second physical frame, excluding the physical frame header. This method includes energy randomization by multiplying the sampling points of the symbols to be scrambled by a complex random sequence. The rate of the complex random sequence is consistent with the symbol rate of the physical frame and is reset at the end of each physical frame header. The complex random sequence consists of two real m-sequences, each generated by an 18th-order prototype polynomial to form segments of Gold code. The two prototype polynomials are preset as follows: and .

[0105] Specifically, record the selected scrambling code. The relevant random sequence is And record , and yes , and The first in the sequence If there are 1 symbol, then the m-sequence and Construct it as follows:

[0106] a. Initialization:

[0107] ;

[0108] .

[0109] b. Recursion:

[0110] ;

[0111] .

[0112] Then the first Gold code sequence The definition is as follows:

[0113] ;

[0114] Then convert the above bit sequence into an integer sequence. ( ):

[0115]

[0116] Finally, the A complex scrambling sequence Defined as:

[0117]

[0118] In the above process The range is from 0 to 262142.

[0119] This invention constructs Gold code segments using dual m-sequences, significantly improving sequence length and cross-correlation characteristics. Simultaneously, by combining a frame header reset mechanism, it achieves sequence synchronization between the transmitting and receiving ends while ensuring the independence of scrambling for each frame, overcoming the technical obstacle of synchronizing long-period sequences.

[0120] Through the above technical solutions, the present invention achieves deep randomization of signal energy distribution, effectively reduces the peak-to-average power ratio of the signal power spectrum, and improves the ability to resist narrowband interference; enhances signal confidentiality through the high randomness of Gold codes, preventing unauthorized receivers from parsing the payload; and ensures that the scrambling sequence is accurately aligned at both ends of the transmission and reception based on the synchronization mechanism of frame header reset, avoiding descrambling failure due to sequence asynchrony.

[0121] In some embodiments, the present invention further proposes that the physical frame header includes a synchronization bit, a signaling bit, and a reserved bit. The length of the synchronization bit is determined according to the signal-to-noise ratio of the channel, the length of the signaling bit is obtained by selecting a default length, and the length of the reserved bit is determined according to the functional expansion requirements.

[0122] Synchronization bits are fixed sequences used by the receiver to achieve symbol timing synchronization. They can be implemented using pseudo-random sequences of preset length, such as PN sequences of 512 or 1024 bits. Their length can be dynamically adjusted according to the channel signal-to-noise ratio to balance synchronization performance and overhead. Signaling bits are fields used to transmit physical frame control information. They can be implemented using fixed-length coding structures, such as Reed-Muller coded blocks of default length (512 bits), used to carry modulation and coding schemes, link state parameters, and check information. Reserved bits are undefined fields reserved for future use. They can be implemented by setting variable-length blank areas, for example, dynamically allocating lengths according to future functional expansion needs, providing flexibility for protocol upgrades.

[0123] Specifically, the physical frame header design achieves dynamic adaptation through three functional partitions. The synchronization bit length is dynamically adjusted based on the real-time channel signal-to-noise ratio (SNR). For example, a longer synchronization sequence is selected in low SNR scenarios to enhance synchronization acquisition capabilities, while the synchronization sequence is shortened in high SNR scenarios to reduce overhead. The signaling bits employ a fixed-length encoding structure, such as a default configuration of 512 bits, ensuring efficient transmission of control information through a predefined encoding format. The reserved bit length is determined based on system upgrade requirements. For example, to support new modulation schemes or security algorithm extensions, the reserved bit region length can be dynamically allocated without affecting the existing protocol structure. This design enables the physical frame header to possess channel condition adaptability and protocol expansion space while ensuring basic functionality.

[0124] This invention solves the risk of synchronization loss under adverse channel conditions and the compatibility problem during protocol iteration by separating the synchronization bit, signaling bit and reserved bit and establishing a dynamic adjustment mechanism.

[0125] Through the above technical solutions, the present invention achieves flexible configuration of the physical frame header structure, optimizes synchronization performance according to channel quality, ensures the reliability of control information through standardized signaling transmission, and reserves scalability space to support future functional upgrades, significantly improving the adaptability and protocol evolution capability of the high-order satellite-to-ground communication system in complex environments.

[0126] In some embodiments, the present invention further proposes that the inner interleaving process adopts an N×M rectangular interleaving structure to adapt to the coding characteristics of the coded frame; and the outer interleaving process adopts convolutional interleaving to reduce data processing latency.

[0127] The N×M rectangular interleaving structure refers to writing the encoded frame data row-by-row into an N x M matrix and then reading it column-by-column to rearrange bit positions. This can be implemented using a rectangular matrix with a fixed number of rows and columns. By adjusting the number of rows and columns to adapt to different encoding parameters, the impact of burst errors on encoding performance can be mitigated. Convolutional interleaving refers to using shift register groups to perform delayed interleaving of data. This can be implemented by parallel processing of register chains with different delays. By reducing data buffering time, processing latency is reduced, making it suitable for scenarios with high real-time requirements.

[0128] Specifically, during the frame encoding process, a rectangular interleaving structure is first used to rearrange the bits of the LDPC-encoded data. Row and column transformations distribute continuous errors across different coding blocks, improving the error correction capability of the error-correcting code. Subsequently, convolutional interleaving is used for external interleaving, employing multiple shift channels with varying delays to achieve symbol-level interleaving. Compared to traditional block interleaving, convolutional interleaving allows output to begin without waiting for a complete data block, effectively reducing data processing latency and meeting the real-time requirements of high-bit-rate transmission. These two interleaving methods are optimized for coding characteristics and latency constraints, respectively. Rectangular interleaving enhances resistance to sudden interference, while convolutional interleaving reduces system processing latency, jointly ensuring reliable transmission of high-order modulated signals in complex channel environments.

[0129] This invention employs a layered interleaving design, cascading two interleaving processes with different mechanisms after encoding. This retains the advantages of rectangular interleaving in adapting to encoding characteristics while introducing the pipelined processing characteristics of convolutional interleaving. Under the same error correction performance, it reduces the interleaving processing latency and avoids the problem of transmission delay accumulation caused by increasing the interleaving depth in traditional schemes.

[0130] Through the above technical solution, the present invention effectively solves the problem of continuous bit error caused by phase noise and Doppler effect in high-order modulation signals in satellite-to-ground channels. It improves error correction efficiency by dispersing burst errors through rectangular interleaving, and reduces system processing latency by utilizing the pipeline characteristics of convolutional interleaving. It achieves both transmission reliability and real-time requirements without increasing hardware complexity, and provides a feasible physical layer processing solution for high-order, high-code-rate satellite-to-ground communication.

[0131] The following description uses a specific physical frame structure obtained by the physical frame structure design method for high-order, high-code-rate satellite-to-ground wireless communication of the present invention as an example: Figure 2 This is a schematic diagram of the physical frame structure, such as... Figure 2 As shown, the physical frame structure can include two parts: baseband frame assembly and physical frame assembly. Baseband frame assembly includes processing steps such as baseband frame header insertion, baseband frame scrambling, encoding, and internal interleaving. Physical frame assembly includes processing steps such as external interleaving, symbol mapping, symbol spreading, adding physical frame headers, adding pilots, and physical frame scrambling.

[0132] For data slicing: When the business data length DPL (Data Package Length, in bits) is greater than the data slice length DFL (Data Field Length, in bits), the business data is sliced, and each slice has a length of DFL. When the slice data is less than DFL, padding is performed so that the length of the padded data is DFL. The padding data is customizable, such as a 01010101 sequence without special meaning, or a user-defined sequence with special meaning. The data slice length DFL is related to the unencoded data length Kldpc and the baseband frame header length BBHL, with the relationship: DFL = Kldpc – BBHL. The DFL length can be designed to be variable to suit different encoding and decoding methods.

[0133] (2) Baseband frame assembly:

[0134] A baseband frame consists of three parts: the baseband frame header (BBHEADER), the data field (DATA FIELD), and the parity check field (LDPCFEC).

[0135] (21) Baseband frame header:

[0136] Add a baseband frame header of length BBHL (BaseBand Header Length, in bits) to the front of each slice data field to complete the baseband frame assembly. The baseband frame length is Kldpc (in bits).

[0137] The baseband frame length Kldpc is designed to be the length of the data before encoding. The Kldpc length is designed to be variable to suit different encoding and decoding methods.

[0138] The length and content of the baseband frame header can be designed. This invention suggests that the baseband frame header length BBHL be designed to be 64 bits. The baseband frame content includes, but is not limited to: service data identifier, baseband frame effective length identifier (DFL - slice padding length), baseband frame count, etc.

[0139] The business data identifier is defined as 8 bits to identify different business data types;

[0140] The effective length identifier of the baseband frame is defined as 14 bits, and a value of 0 indicates that the current baseband frame is entirely filled.

[0141] The baseband frame count is defined as 32 bits, starting from 0 and accumulating, with a cyclic count from 0 to 2^32-1;

[0142] Reserve 10 bits for feature expansion.

[0143] (22) Baseband frame scrambling:

[0144] Baseband frame scrambling is performed on the baseband frame header and baseband frame data (length Kldpc). The scrambling polynomial and initial phase are configurable. The baseband frame header can be optionally included in the scrambling. Scrambling is reset at the beginning of each baseband frame, meaning the scrambling sequence is identical for each baseband frame.

[0145] One possible suggestion is: the initial scrambling phase is 100101010000000, and the polynomial is... The first 64 scrambling sequences are:

[0146] 0000001111110110000010000011010000110000101110001010001110010001110010011.

[0147] (3) Error correction coding:

[0148] Error correction coding can use various block codes, but LDPC codes are recommended. The baseband frame coding is shown in the figure below, where Kldpc is the baseband frame length and Nldpc is the length after LDPC encoding; both units are bits.

[0149] (4) Intertwined:

[0150] (41) Internal interweaving:

[0151] Bit interleaving is performed on LDPC encoded frames using N×M rectangular interleaving, where N×M=Nldpc.

[0152] (42) External interweaving:

[0153] External interleaving performs bit interleaving on L LDPC encoded frames, which can be done using rectangular interleaving or convolutional interleaving. Convolutional interleaving is recommended to reduce processing latency.

[0154] (5) Symbol mapping:

[0155] QPSK mapping:

[0156] For QPSK, every 2 bits are mapped to 1 symbol, and Gray-coded QPSK modulation is used, with an average energy of 1 per symbol.

[0157] 8PSK mapping:

[0158] For 8PSK, every 3 bits are mapped to 1 symbol, using Gray-coded 8PSK modulation, with an average energy of 1 per symbol.

[0159] 16QAM mapping:

[0160] For 16QAM, every 4 bits are mapped to 1 symbol, using Gray-coded 16QAM modulation, with an average energy of 1 per symbol.

[0161] 32QAM mapping:

[0162] For 32QAM, every 5 bits are mapped to 1 symbol, using Gray-coded 32QAM modulation, with an average energy of 1 per symbol.

[0163] 64QAM mapping:

[0164] For 64QAM, every 6 bits are mapped to 1 symbol, using Gray-coded 64QAM modulation, with an average energy of 1 per symbol.

[0165] 128QAM mapping:

[0166] For 128QAM, every 7 bits are mapped to 1 symbol, using Gray-coded 128QAM modulation, with an average energy of 1 per symbol.

[0167] 256QAM mapping

[0168] For 256QAM, every 8 bits are mapped to 1 symbol, using Gray-coded 256QAM modulation, with an average energy of 1 per symbol.

[0169] (6) Physical frame assembly:

[0170] (61) Inserting pilot:

[0171] The length after symbol mapping (or symbol spreading) is L×N ldpe Data frames of length / n (where n is the modulation order, e.g., n=2 for QPSK, n=8 for 2560AM) are interspersed with pilot blocks of length PBL (Pilot Block Length) at intervals of data blocks of length DBL (Data Block Length). The lengths of L, DBL, and PBL are configurable. Considering factors such as received signal-to-noise ratio, received power intensity, received power variation, transmitted power, and Doppler effect, this invention recommends DBL=480 symbols and PBL=16 symbols.

[0172] (62) Add physical frame header:

[0173] Add a physical frame header of length PLHL (Phase Layer Header Length) to form a complete physical frame. The total length PLL (Phase Layer Length) of the physical frame (second physical frame) after inserting the pilot and frame header is PLHL + PBL + ceil (LN). ldpc / DBL+1)×PBL, where ceil represents rounding up.

[0174] The physical frame header includes synchronization bits, signaling bits, and reserved bits.

[0175] Pilot, synchronization, and signaling bits all use pi / 2 BPSK modulation.

[0176] The synchronization bit length is flexibly configurable, for example, using 512 or 1024.

[0177] When designed for 512 bits, the first 512 bits of PN9 are used as synchronization bits. The primitive polynomial design of PN9 is as follows: The initial phase design is 101001001.

[0178] The signaling length is flexibly configurable, with a recommended value of 512 bits and 8 RM (64,7) encodings. The signaling area is used to transmit physical frame information and implement functions such as VCM / ACM. The transmitted information includes, but is not limited to, the encoding and modulation scheme MODCOD of this physical frame, signal-to-noise ratio measurement, power measurement, transmit power, link status, number of encoded frames L, number of pilot blocks, pilot spacing, CRC check, etc.

[0179] (7) Physical frame scrambling:

[0180] Energy randomization is performed on each physical frame symbol (excluding the frame header), which is achieved by multiplying the sampled points by a complex random sequence to obtain the scrambled symbol.

[0181] In a specific implementation, if spread spectrum is required, the following spread spectrum modes are available:

[0182] For extremely low signal-to-noise ratios, a symbolic spread spectrum mode is used, supporting 1x, 2x, 4x, and 8x spread spectrum. 1 indicates no spread spectrum. When using QPSK+8x spread spectrum, it is suitable for extremely low signal-to-noise ratios.

[0183] In a specific implementation, the spectral efficiency of a designable physical frame structure is shown in Table 2 below:

[0184] Table 2

[0185]

[0186] In a specific implementation process, a comparison between the physical frame structure of this invention and the DVB-S2 frame structure yields the following conclusions:

[0187] 1. The frame type of DVB-S2 is a single frame, while the frame type of this invention is a composite frame. This invention improves the physical frame transmission capability while ensuring the efficiency of physical frames.

[0188] 2. The baseband frame of DVB-S2 is 80-bit frame header + data + padding, while the baseband frame of this invention is 64-bit frame header + data + padding. The custom frame header redefines the baseband frame header content to adapt to high-level and high-speed applications; and the reduced frame header length improves the efficiency of the baseband frame.

[0189] 3. DVB-S2 uses rectangular interleaving of the encoded frame, while this invention uses two-level interleaving, including rectangular interleaving of the encoded frame and convolutional interleaving of the physical frame. This improves the ability to resist burst errors.

[0190] 4. The constellation mapping of DVB-S2 is QPSK, 8PSK, 16APSK, and 32APSK, which belong to low-order modulation. The constellation mapping of this invention is QPSK\8PSK\16QAM\32QAM\64QAM\128QAM\256QAM, which covers both low-order and high-order mappings, increasing the adaptability to high-order modulations.

[0191] 5. The DVB-S2 codec is BCH+LDPC, while the codec of this invention can be extended as needed.

[0192] 6. The physical frame structure of DVB-S2 is frame synchronization header + physical layer signaling + data, while the physical frame structure of this invention is synchronization bit + signaling bit + reserved bit + data. This extends the frame synchronization bit length and improves the ability to operate at extremely low signal-to-noise ratios. The length of each unit in the frame structure of this invention takes into account high-bit-rate parallel implementation, making it easy to implement high-speed data processing using FPGA. It also extends the physical layer signaling, enhancing the capabilities of the physical frame. DVB-S2 uses one RM, containing only 7 bits of signaling information, while this invention uses multiple RMs, such as 8 RMs, containing a total of 56 bits of signaling information, increasing the flexibility of the physical frame. The reserved bits reserve functional extensions for higher-order systems.

[0193] 7. DVB-S2 lacks ultra-low signal-to-noise ratio (SNR) reception, while this invention adds a spread spectrum mode, making it suitable for extremely low SNR. In comparison, the lowest SNR applicable to DVB-S2 is EsN0 = -2dB, while the physical frame header used in this invention can achieve synchronization at extremely low SNRs of EsN0 = -15dB (length 512) or EsN0 = -18dB (length 1024). Furthermore, using QPSK with 8x spread spectrum and LDPC encoding at 1 / 4 code rate, data reception at EsN0 = -15dB can be achieved.

[0194] It should be noted that all relevant information that may be involved in the various embodiments of the present invention is processed in strict accordance with the requirements of laws and regulations, following the principles of legality, legitimacy, and necessity, based on the reasonable purpose of the business scenario, and is information that users actively provide or that is generated due to the use of the product / service, as well as information that is obtained with the user's authorization.

[0195] The information processed by this invention may vary depending on the specific product / service scenario and should be based on the specific scenario in which the user uses the product / service. This may involve user account information, device information, or other related information. This invention will handle the relevant information and its processing with the utmost diligence.

[0196] This invention places great importance on the security of related information and has adopted reasonable and feasible security protection measures that comply with industry standards to protect related information and prevent unauthorized access, public disclosure, use, modification, damage or loss of related information.

[0197] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for designing a physical frame structure suitable for high-order high-rate wireless communication between a satellite and the earth, characterized in that, include: The business data is sliced ​​according to a preset length, and a baseband frame is generated based on the obtained data slices; The baseband frame is scrambled to obtain a scrambled baseband frame; wherein the baseband frame includes a frame header, a data area, and a check area; The scrambled baseband frames are sequentially subjected to preset error correction coding processes to obtain coded frames; The encoded frame is subjected to internal interleaving to obtain internally interleaved data, which is then used to form the first physical frame; The first physical frame is subjected to external interleaving processing to obtain externally interleaved data; The externally interleaved data is mapped into a symbol stream; wherein the symbol stream employs a preset high-order modulation scheme; The physical frame is assembled based on the symbol stream to obtain a second physical frame; wherein, the physical frame assembly includes inserting pilot blocks at preset intervals and adding a physical frame header; Scrambling is performed on the symbols to be scrambled in the second physical frame, excluding the physical frame header, to obtain a scrambled physical frame, and data transmission is performed based on modulation of the scrambled physical frame; Obtain the performance parameters of the satellite-to-ground wireless channel; the performance parameters include at least one of the following: received signal-to-noise ratio, received power intensity, received power variation, transmitted power, and Doppler. Based on the performance parameters, the satellite-to-ground communication scenario is determined; the satellite-to-ground communication scenario includes at least one of the following: clear sky high elevation angle scenario, conventional medium and low elevation angle scenario, and rain-affected signal scenario; Based on the described satellite-to-ground communication scenario, determine the constraint priority; Based on the constraint priority, determine the candidate value ranges for the number of interleaved data, the length of the preset interval, and the length of the pilot block; Based on their respective candidate value ranges, each candidate value is selected as its current candidate value, and iterative verification is performed based on the constraint model until each candidate value satisfies all constraints of the constraint model, thereby obtaining the number of interleaved data, the length of the preset interval, and the length of the pilot block.

2. The method of claim 1, wherein the physical frame structure is designed for satellite-to-ground high-order high-rate wireless communication. Based on the symbol stream, physical frames are assembled to obtain a second physical frame, including: The spreading factor of the symbol stream is determined based on the signal-to-noise ratio of the satellite-to-ground wireless channel; The symbol stream is spread according to the spreading factor to obtain a spread spectrum symbol stream; The physical frame header is added to the spread spectrum symbol stream, and the pilot blocks are inserted at preset intervals.

3. The method of claim 1, wherein the physical frame structure is designed for satellite-to-ground high-order high-rate wireless communication. The constraint model includes delay constraints and overhead constraints; The delay constraint is that the ratio of the total length of the second physical frame to the scene coefficient of different satellite-to-ground communication scenarios is less than a preset duration; The overhead constraint is that the ratio of the total length of the pilot to the total length of the second physical frame is less than a preset overhead value; The total length of the second physical frame is the sum of the length of the physical frame header, the length of all pilot blocks, and the length of the spread spectrum symbol stream.

4. The method of claim 1, wherein the physical frame structure is designed for satellite-to-ground high-order high-rate wireless communication. Also includes: The combination parameters of the higher-order modulation scheme and error correction coding scheme are adaptively adjusted based on the signal-to-noise ratio of the satellite-to-ground wireless channel.

5. The method of claim 4, wherein the physical frame structure is designed for satellite-to-ground high-order high-rate wireless communication. Based on the signal-to-noise ratio of the satellite-to-ground wireless channel, the combined parameters of the higher-order modulation scheme and error correction coding scheme are adaptively adjusted, including: When the signal-to-noise ratio is less than the lower threshold, the pre-constructed combined parameter label is decremented by 1; when the signal-to-noise ratio is greater than the upper threshold, the combined parameter label is incremented by 1. The combination parameter labels are the labels of the combination parameters of different higher-order modulation methods and error correction coding methods arranged in sequence.

6. The method of designing a physical frame structure suitable for satellite-to- earth higher order and higher rate wireless communications according to claim 1, wherein, Scrambling processing is performed on the symbols to be scrambled in the second physical frame, excluding the physical frame header, including: Energy randomization is achieved by multiplying the sample points of the symbols to be scrambled in the second physical frame by a complex random sequence; wherein the rate of the complex random sequence is consistent with the physical frame symbol rate, and the complex random sequence is reset at the end of each physical frame header; the complex random sequence is composed of two real m sequences, and the two m sequences are generated by 18-order prototype polynomials, respectively, to finally form a segment of Gold code, and the two prototype polynomials are respectively preset as and .

7. The method of claim 1, wherein the physical frame structure is designed for satellite-to-ground high-order high-rate wireless communication. The physical frame header includes synchronization bits, signaling bits, and reserved bits; The method further includes: Determine the length of the synchronization bit based on the signal-to-noise ratio of the channel; Select the default length to obtain the length of the signaling bits; The length of the reserved bits is determined based on the functional expansion requirements.

8. The method of designing a physical frame structure suitable for satellite-to- earth high-order high-code-rate wireless communication according to any one of claims 1-7, characterized in that, The internal interleaving process adopts an N×M rectangular interleaving structure to adapt to the coding characteristics of the coded frame; The external interleaving process employs convolutional interleaving to reduce data processing latency.

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