A low earth orbit satellite rate adaptation method and system based on probabilistic shaping

Abstract

The application provides a low-orbit satellite rate adaptive method and system based on probability shaping, and the method comprises the following steps: acquiring a current channel quality parameter; calculating a quality parameter deviation relative to a preset reference point based on the current channel quality parameter; judging whether the quality parameter deviation exceeds a preset hysteresis threshold value, and making an update decision to obtain a target shaping factor; and adjusting a probability distribution of modulation constellation symbols according to the target shaping factor to realize rate adaptation. On the basis of fully exerting the continuous rate adjustment advantage of the probability constellation shaping technology, the application introduces a hysteresis interval lookup table mechanism to solve the technical defects of frequent shaping factor update and large control overhead in the existing point-by-point lookup table scheme.

Description

Technical Field

[0001] This invention relates to the field of satellite communication technology, and more specifically, to a method and system for adaptive low-Earth orbit satellite rate based on probabilistic shaping. Background Technology

[0002] In recent years, the successful deployment of low-Earth orbit (LEO) satellite constellations has propelled satellite communications to the forefront of network infrastructure. Unlike traditional geostationary orbit (GEO) satellite networks, LEO satellites orbit the Earth at extremely high speeds, resulting in drastic dynamic changes in the satellite-to-ground channel, including time-varying Doppler shifts and rapidly changing propagation environments, which severely impact communication performance.

[0003] However, existing rate adaptation methods based on probabilistic shaping still have significant drawbacks. Current mainstream solutions generally employ a point-by-point real-time lookup table mechanism, where the shaping factor is obtained by querying a lookup table for each transmission time slot based on the instantaneous channel state. In the high-dynamic channel environment of low-Earth orbit satellites, even small fluctuations in channel quality can trigger frequent adjustments to the shaping factor. This high-frequency parameter update not only increases system control overhead and signaling interaction burden but also causes the shaping factor trajectory to oscillate violently. This limits the practical application of probabilistic shaping technology in resource-constrained onboard environments. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method and system for adaptive low-Earth orbit satellite rate based on probabilistic constellation shaping. This invention fully leverages the advantages of continuous rate adjustment in probabilistic constellation shaping technology and solves the technical defects of frequent shaping factor updates and high control overhead in existing point-by-point lookup schemes by introducing a hysteresis interval lookup mechanism.

[0005] To solve the above problems, the technical solution of the present invention is as follows:

[0006] A probabilistic shaping-based method for low-Earth orbit satellite rate adaptation includes the following steps:

[0007] Get the current channel quality parameters;

[0008] Calculate the quality parameter deviation relative to a preset reference point based on the current channel quality parameters;

[0009] Determine whether the deviation of the quality parameter exceeds a preset hysteresis threshold, and make an update decision to obtain the target forming factor;

[0010] The probability distribution of the modulated constellation symbols is adjusted according to the target shaping factor to achieve rate adaptation.

[0011] Preferably, the channel quality parameters include the equivalent signal-to-noise ratio.

[0012] Preferably, the quality parameter deviation is the absolute value of the difference between the current channel quality parameter and the preset reference point.

[0013] Preferably, the step of determining whether the deviation of the quality parameter exceeds a preset hysteresis threshold and making an update decision to obtain the target shaping factor specifically includes: comparing the deviation with the hysteresis threshold; if it exceeds the hysteresis threshold, triggering a lookup table update operation: querying the probability shaping lookup table based on the current channel quality parameter to obtain the target shaping factor, and updating the current channel quality parameter to a new reference point; if it does not exceed the hysteresis threshold, not triggering an update, and maintaining the use of the previously obtained shaping factor.

[0014] Preferably, the probability shaping lookup table is a probability constellation shaping lookup table based on the Maxwell-Boltzmann distribution, and the shaping factor is used to control the transmission probability of symbols on different amplitude rings in the amplitude phase modulation constellation.

[0015] Furthermore, the present invention also provides a low-Earth orbit satellite rate adaptive system based on probabilistic shaping, comprising:

[0016] The channel quality monitoring and deviation calculation unit is used to acquire the current channel quality parameters in real time and calculate the deviation of the current channel quality parameters from a preset reference point.

[0017] The hysteresis judgment and update decision unit is used to determine whether the deviation of the quality parameter exceeds a preset hysteresis threshold. Only when the deviation of the quality parameter exceeds the hysteresis threshold will the lookup table update operation be triggered.

[0018] The lookup table update module is used to obtain a target shaping factor by querying a probability shaping lookup table based on the current channel quality parameter when the quality parameter deviation exceeds the hysteresis threshold, and update the current channel quality parameter to a new reference point; if the quality parameter deviation does not exceed the hysteresis threshold, the previously obtained shaping factor is retained.

[0019] The probability shaping execution module is used to adjust the probability distribution of the modulated constellation symbols according to the target shaping factor.

[0020] Compared with existing technologies, this invention constructs a rate adaptive system based on probabilistic constellation shaping technology. By adjusting the shaping factor to control the probability distribution of modulation constellation symbols, it achieves continuous fine-grained adjustment of transmission rate. It introduces a hysteresis interval lookup table mechanism, which calculates the deviation of the current channel quality from a preset reference point and determines whether it exceeds the hysteresis threshold. The lookup table is only updated when the deviation exceeds the threshold. This invention only requires adding hysteresis comparison logic to the existing probabilistic shaping lookup table query process. Without modifying the hardware architecture or RF front end, the system can be plug-and-play. Attached Figure Description

[0021] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0022] Figure 1 This is a diagram of the overall architecture of the low-Earth orbit satellite rate adaptive system based on probabilistic shaping according to the present invention.

[0023] Figure 2 This is a flowchart of the low-Earth orbit satellite rate adaptation method based on probabilistic shaping according to the present invention. Detailed Implementation

[0024] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0025] Specifically, this invention provides a low-Earth orbit satellite rate adaptive system based on probabilistic shaping, such as... Figure 1 As shown, the system includes:

[0026] The channel quality monitoring and deviation calculation unit is used to acquire the current channel quality parameters (such as equivalent signal-to-noise ratio SNR) in real time, and calculate the quality parameter deviation of the current channel quality parameters relative to a preset reference point. The quality parameter deviation reflects the cumulative change of the channel state relative to the last update time.

[0027] The hysteresis judgment and update decision unit is used to determine whether the deviation of the quality parameter exceeds a preset hysteresis threshold. Only when the deviation of the quality parameter exceeds the hysteresis threshold will the lookup table update operation be triggered.

[0028] The lookup table update module is used to obtain the target shaping factor based on the current channel quality parameter when the quality parameter deviation exceeds the hysteresis threshold, and update the current channel quality parameter to a new reference point; if the quality parameter deviation does not exceed the hysteresis threshold, the previously obtained shaping factor is retained.

[0029] The probability shaping execution module is used to adjust the probability distribution of the modulated constellation symbols according to the target shaping factor.

[0030] like Figure 2 As shown, the present invention also provides a low-Earth orbit satellite rate adaptation method based on probabilistic shaping, the method comprising the following steps:

[0031] S1: Obtain the current channel quality parameters;

[0032] Specifically, in each transmission time slot, the current channel quality parameter is obtained, which is the equivalent signal-to-noise ratio (SNR).

[0033] S2: Calculate the quality parameter deviation relative to the preset reference point based on the current channel quality parameters;

[0034] Specifically, in each transmission time slot, the current channel quality parameter is acquired, and the quality parameter deviation of the current channel quality parameter relative to a preset reference point is calculated. The quality parameter deviation is the absolute value of the difference between the current channel quality parameter and the reference point.

[0035] S3: Determine whether the deviation of the quality parameter exceeds the preset hysteresis threshold, and make an update decision to obtain the target forming factor;

[0036] Specifically, the deviation is compared with a hysteresis threshold. If it exceeds the hysteresis threshold, a lookup table update operation is triggered: the probabilistic shaping lookup table is queried based on the current channel quality parameters to obtain the target shaping factor, and the current channel quality parameters are updated to a new reference point. If the deviation does not exceed the hysteresis threshold, no update is triggered, and the previously obtained shaping factor is retained.

[0037] The probability shaping lookup table is a probability constellation shaping lookup table based on the Maxwell-Boltzmann distribution, and the shaping factor is used to control the transmission probability of symbols on different amplitude rings in the amplitude phase modulation (APSK) constellation.

[0038] S4: Adjust the probability distribution of the modulated constellation symbols according to the target shaping factor to achieve rate adaptation.

[0039] Specifically, offline, a binary search algorithm is used to find the optimal shaping factor within a set shaping factor range that meets the system's target bit error rate requirement, and this optimal factor is stored in a lookup table (LUT). During execution, the optimal shaping factor is determined based on the currently determined shaping factor. The probability mass function for generating constellation points is based on the Maxwell-Boltzmann distribution, and its probability distribution is given by the formula. ,in This is a normalization constant. A distributed matcher maps the uniform bitstream to a symbol sequence conforming to the above probability distribution, which is then modulated and transmitted.

[0040] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A low-Earth orbit satellite rate adaptive method based on probabilistic shaping, characterized in that, The method includes the following steps: Get the current channel quality parameters; Calculate the quality parameter deviation relative to a preset reference point based on the current channel quality parameters; Determining whether the deviation of the quality parameter exceeds a preset hysteresis threshold and making an update decision to obtain the target shaping factor specifically includes: comparing the deviation with the hysteresis threshold; if it exceeds the hysteresis threshold, triggering a lookup table update operation: querying the probability shaping lookup table based on the current channel quality parameter to obtain the target shaping factor, and updating the current channel quality parameter to a new reference point; if it does not exceed the hysteresis threshold, no update is triggered, and the previously obtained shaping factor is retained. The probability distribution of the modulated constellation symbols is adjusted according to the target shaping factor to achieve rate adaptation.

2. The low-Earth orbit satellite rate adaptive method based on probabilistic shaping according to claim 1, characterized in that, The channel quality parameters include the equivalent signal-to-noise ratio.

3. The low-Earth orbit satellite rate adaptive method based on probabilistic shaping according to claim 1, characterized in that, The quality parameter deviation is the absolute value of the difference between the current channel quality parameter and the preset reference point.

4. The low-Earth orbit satellite rate adaptive method based on probabilistic shaping according to claim 1, characterized in that, The probability shaping lookup table is a probability constellation shaping lookup table based on the Maxwell-Boltzmann distribution, and the shaping factor is used to control the transmission probability of symbols on different amplitude rings in the amplitude phase modulation constellation.

5. A probabilistic shaping-based low-Earth orbit satellite rate adaptation system, used to implement the probabilistic shaping-based low-Earth orbit satellite rate adaptation method as described in claim 1, characterized in that, The system includes: The channel quality monitoring and deviation calculation unit is used to acquire the current channel quality parameters in real time and calculate the deviation of the current channel quality parameters from a preset reference point. The hysteresis judgment and update decision unit is used to determine whether the deviation of the quality parameter exceeds a preset hysteresis threshold. Only when the deviation of the quality parameter exceeds the hysteresis threshold will the lookup table update operation be triggered. The lookup table update module is used to obtain a target shaping factor by querying a probability shaping lookup table based on the current channel quality parameter when the quality parameter deviation exceeds the hysteresis threshold, and update the current channel quality parameter to a new reference point; if the quality parameter deviation does not exceed the hysteresis threshold, the previously obtained shaping factor is retained. The probability shaping execution module is used to adjust the probability distribution of the modulated constellation symbols according to the target shaping factor.

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