Method, device, base station and storage medium for determining NTN feeder link delay parameters

Abstract

The present application provides a method, device, base station, and storage medium for determining NTN feeder link delay parameters. The base station of the present application calculates the satellite-to-ground distance corresponding to multiple sample moments of the detection period based on the ephemeris information and epoch time corresponding to the detection period, and then determines the fitting coefficient of the distance-time function corresponding to the detection period by curve fitting the satellite-to-ground distance. The common delay parameter is determined based on the fitting coefficient, thereby improving the accuracy and efficiency of determining the common delay parameter. This allows the user terminal to accurately estimate the common delay of the feeder link based on the common delay parameter and perform corresponding timing compensation to ensure signal synchronization, thereby resolving the technical problem in the prior art where the base station cannot accurately determine the common delay parameter. Furthermore, the present application can determine the changing trend of the satellite-to-ground distance over a longer period of time based on calculations of fewer sample points, thereby ensuring the accuracy of delay assessment with lower computational overhead.

Description

Technical Field

[0001] The present application relates to the field of wireless communications, and in particular to a method, device, base station, and storage medium for determining NTN feeder link delay parameters. Background Art

[0002] NTN (Non-Terrestrial Network) refers to a wireless network carried by artificial satellites or drone platforms. Satellites in NTN that implement payload transmission or payload regeneration complete service coverage for users by generating communication beams and forming an elliptical illumination area in the service area. In NTN, the signal transmission path between the base station and the user terminal includes a service link and a feeder link, which are the transmission paths from the user terminal to the satellite and the transmission path from the ground gateway to the satellite, respectively. A reference point is defined in the feeder link, and the timing advance of the user terminal is the round-trip delay from the satellite to the reference point, which is composed of the round-trip delay of the service link and the common delay of the feeder link. The common delay is the round-trip delay from the satellite to the reference point on the feeder link, which is usually derived and determined by the relevant common delay parameters provided by the network. ‌

[0003] However, the prior art lacks a public analysis algorithm for the derivation and determination of common delay parameters, and the base station is unable to accurately determine the common delay parameters, resulting in the inability of subsequent user terminals to accurately estimate and compensate for the delay of the feeder link. Summary of the Invention

[0004] The present application provides a method, apparatus, base station, and storage medium for determining NTN feeder link delay parameters. In the present application, the base station determines common delay parameters by performing curve fitting based on the satellite-to-ground distance corresponding to a detection period. This improves the accuracy of determining the common delay parameters, enabling user terminals to accurately estimate the common delay of the feeder link based on the common delay parameters and perform corresponding timing compensation. This application solves the technical problem in the prior art where base stations are unable to accurately determine the common delay parameters.

[0005] In a first aspect, the present application provides a method for determining NTN feeder link delay parameters, the method being applicable to a base station, the method comprising:

[0006] Determine the ephemeris information of the service satellite and the corresponding epoch time in real time during the detection period;

[0007] Determining the satellite-to-ground distance corresponding to each sample moment according to the predetermined gateway station position coordinates, the ephemeris information, and the epoch time, wherein the detection period includes a plurality of the sample moments;

[0008] Curve fitting is performed based on the satellite-to-ground distance corresponding to each sample moment to determine a fitting coefficient of a distance-time function. A common delay parameter of the feeder link is determined based on a predetermined fixed delay and the fitting coefficient, where the distance-time function is a function that characterizes how the satellite-to-ground distance changes over time.

[0009] The distance-time function is a second-order function, the fitting coefficient includes a zero-order coefficient, a first-order coefficient, and a second-order coefficient, the common delay parameter includes a zero-order constant coefficient, a first-order drift rate coefficient, and a second-order drift rate coefficient, and determining the common delay parameter of the feeder link based on the predetermined fixed delay and the fitting coefficient includes:

[0010] Determining a zero-order constant coefficient of the feeder link according to the zero-order coefficient and a predetermined fixed time delay;

[0011] determining a first-order drift rate coefficient of the feeder link based on the first-order coefficient;

[0012] A second-order drift rate coefficient of the feeder link is determined according to the second-order coefficient.

[0013] The time intervals between two adjacent sample moments are the same, and the curve fitting is performed according to the satellite-to-ground distance corresponding to each sample moment to determine the fitting coefficient of the distance-time function, including:

[0014] Performing curve fitting on the satellite-to-ground distance corresponding to each sample moment by the least squares method to determine the fitting coefficient of the distance-time function;

[0015] Determining the theoretical satellite-to-earth distance corresponding to each sample moment according to the distance-time function after the fitting coefficient is determined;

[0016] Determine a mean square error based on the theoretical satellite-to-ground distance corresponding to each sample moment and the error between the satellite-to-ground distances;

[0017] When the mean square error exceeds a preset threshold range, the duration of the detection period and / or the time interval of the sample moments are adjusted, the fitting coefficient of the distance-time function of the detection period is re-determined, and the mean square error is updated until the mean square error is within the preset threshold range.

[0018] The adjusting of the duration of the detection period and / or the time interval of the sample moments includes:

[0019] When the mean square error is greater than the maximum value of the preset threshold range, reducing the duration of the detection period and / or the time interval between the sample moments;

[0020] When the mean square error is smaller than the minimum value of the preset threshold range, the duration of the detection period and / or the time interval between the sample moments are increased.

[0021] The fixed delay is determined in advance by:

[0022] determining a minimum distance from the service satellite to the center of the Earth;

[0023] Determining a first distance between the gateway and the center of the earth according to the location coordinates of the gateway;

[0024] A minimum satellite-to-ground distance is determined according to the minimum distance and the first distance, and the fixed delay is determined according to the minimum satellite-to-ground distance.

[0025] The determining of the fixed delay according to the minimum satellite-to-ground distance includes:

[0026] Determining a value range of a scheduling offset parameter based on the minimum satellite-to-ground distance and a vacuum propagation speed of electromagnetic waves;

[0027] The value of the scheduling offset parameter is determined within the value range, and the fixed delay is determined according to the value of the scheduling offset parameter.

[0028] The determining of the satellite-to-ground distance corresponding to each sample time according to the predetermined gateway station position coordinates, the ephemeris information, and the epoch time includes:

[0029] Determining a satellite position vector corresponding to each sample moment according to the ephemeris information and the epoch time;

[0030] The satellite-to-ground distance corresponding to each sample moment is determined based on the satellite position vector corresponding to each sample moment and the predetermined gateway position coordinates.

[0031] In a second aspect, the present application provides a device for determining NTN feeder link delay parameters, the device being applicable to a base station, and comprising:

[0032] The ephemeris information acquisition module is used to determine the ephemeris information of the service satellite and the corresponding epoch time in real time during the detection period;

[0033] a satellite-to-ground distance determination module, configured to determine the satellite-to-ground distance corresponding to each sample moment based on predetermined gateway location coordinates, the ephemeris information, and the epoch time, wherein the detection period includes a plurality of the sample moments;

[0034] A delay parameter determination module is configured to perform curve fitting based on the satellite-to-ground distance corresponding to each sample moment to determine a fitting coefficient of a distance-time function, and determine a common delay parameter of the feeder link based on a predetermined fixed delay and the fitting coefficient, where the distance-time function is a function that characterizes how the satellite-to-ground distance changes over time.

[0035] In a third aspect, the present application provides a base station, comprising: one or more processors; and a storage device configured to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the NTN feeder link delay parameter determination method described in the first aspect.

[0036] In a fourth aspect, the present application provides a non-volatile storage medium storing computer-executable instructions, wherein the computer-executable instructions, when executed by a computer processor, are configured to execute the method for determining the NTN feeder link delay parameters described in the first aspect.

[0037] As described above, the present application provides a method, device, base station, and storage medium for determining NTN feeder link delay parameters. In the present application, the base station solves the satellite-to-ground distance corresponding to multiple sample moments of the detection period based on the ephemeris information and epoch time corresponding to the detection period, and then determines the fitting coefficient of the distance-time function corresponding to the detection period by curve fitting the satellite-to-ground distance. The common delay parameter is determined based on the fitting coefficient, thereby improving the accuracy and efficiency of determining the common delay parameter. This allows the user terminal to accurately estimate the common delay of the feeder link based on the common delay parameter and perform corresponding timing compensation to ensure signal synchronization, thus solving the technical problem in the prior art where the base station cannot accurately determine the common delay parameter. In addition, the present application can determine the changing trend of the satellite-to-ground distance over a longer period of time based on the calculation of fewer sample points, thereby ensuring the accuracy of delay evaluation with lower computational overhead. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the NTN network structure of the transparent transmission architecture provided in this application.

[0039] Figure 2 This is a schematic diagram of the NTN network structure of the regeneration architecture provided in this application.

[0040] Figure 3 This is a schematic diagram of the timing advance of the traditional NTN provided in this application.

[0041] Figure 4 This is a schematic diagram of the timing advance of the enhanced NTN provided by this application.

[0042] Figure 5This is a schematic diagram of the timing advance components of the NTN provided in this application.

[0043] Figure 6 This is a flowchart of a method for determining NTN feeder link delay parameters provided in this application.

[0044] Figure 7 This is a flow chart of determining the satellite-to-earth distance corresponding to each sample moment provided by this application.

[0045] Figure 8 This is a flowchart of another method for determining NTN feeder link delay parameters provided by this application.

[0046] Figure 9 This is a structural diagram of a device for determining NTN feeder link delay parameters provided by this application.

[0047] Figure 10 A schematic diagram of the structure of a base station provided in this application. DETAILED DESCRIPTION

[0048] The following description and accompanying drawings sufficiently illustrate specific embodiments of the present application to enable those skilled in the art to practice them. The examples represent only possible variations. Unless expressly required, individual components and functions are optional, and the order of operations may vary. Portions and features of some embodiments may be included in or replace portions and features of other embodiments. The scope of the embodiments of the present application includes the entire scope of the claims, as well as all available equivalents of the claims. Herein, each embodiment may be referred to individually or collectively by the term "invention," which is merely for convenience and is not intended to automatically limit the scope of the application to any single invention or inventive concept if more than one invention is in fact provided. Herein, relational terms such as first and second, etc., are used solely to distinguish one entity or operation from another, and do not require or imply any actual relationship or order between these entities or operations. Furthermore, the terms "comprise," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed. The various embodiments herein are described in a progressive manner, with each embodiment focusing on the differences from the other embodiments. Reference can be made to the common and similar parts between the various embodiments. For structures, products, etc. disclosed in the embodiments, the description is relatively simple because they correspond to the parts disclosed in the embodiments. For relevant parts, refer to the method description.

[0049] NTN (Non-Terrestrial Network) refers to a wireless network carried by artificial satellites or drone platforms. Compared with traditional 4G / 5G terrestrial communications, NTN can provide good supplementary services, such as coverage gap filling, large-scale broadcasting, and support for high-speed mobile users (such as passengers on passenger aircraft and other vehicles). Satellites that implement payload transparent transmission or payload regeneration in NTN complete service coverage for users by generating communication beams and forming an elliptical illumination area in the service area. Taking the 5G network architecture as an example, Figure 1 and Figure 2 As shown, Figure 1 This is a schematic diagram of the NTN network structure of the transparent transmission architecture provided in this application. In this transparent transmission architecture, base stations (generation NodeB, gNB) are deployed at ground gateways. Figure 2 This is a schematic diagram of the NTN network structure of the regenerative architecture provided in this application. Under the regenerative architecture, the base station is deployed on the satellite payload.

[0050] In wireless networks, user equipment (UE) requires a certain timing advance (TA) for the transmission boundary of uplink signals to compensate for signal transmission delays and ensure that uplink signals reach the base station within the specified time window. Compared with terrestrial networks, the signal propagation distance of NTN networks is greatly increased, so the timing advance (TA) of user terminal UE communication with NTN also needs to be significantly increased. For example, Figure 3 As shown, Figure 3 The timing advance diagram of the traditional NTN provided in this application is as follows: Figure 3 In this example, the uplink and downlink timing boundaries on the gNB are aligned. The downlink timing boundary on the user terminal (UE) lags behind the gNB's downlink timing boundary by a certain amount, representing the downlink radio signal propagation delay. The uplink timing boundary on the UE leads the gNB's uplink timing boundary by a certain amount, representing the uplink radio signal propagation delay. This shows that the timing advance (TA) on the UE side, i.e., the offset between the uplink and downlink timing boundaries, is roughly equivalent to double the propagation delay. Figure 4 The enhanced NTN timing advance diagram provided in this application shows that since the propagation delay of NTN is large compared with the terrestrial network, the timing advance of the user terminal UE is too large, which is not conducive to control. Therefore, the enhanced timing advance scheme is to change the original alignment of the uplink and downlink timing boundaries on the base station gNB side, so that the uplink timing boundary lags behind the downlink timing boundary by a certain fixed delay, which is conducive to narrowing the adjustment range of the timing advance TA on the user terminal UE side.

[0051] In the transparent transmission architecture, the wireless signal transmission path from NTN's base station gNB to the user terminal UE includes a service link and a feeder link, which are the transmission paths from the user terminal to the satellite and from the ground gateway to the satellite, respectively. In the feeder link, a reference point RP (Reference Point) is defined. The round-trip delay between the reference point RP and the ground gateway is expressed as a parameter. Indicates the uplink timing advance on the UE side. is the round-trip delay from the satellite to the reference point RP, which consists of the round-trip delay of the service link and the common delay (Common TA), such as Figure 5 As shown, Figure 5 Schematic diagram of the timing advance components of the NTN provided in this application. The round-trip delay of the service link is derived by the user terminal UE based on the ephemeris information provided by the network and the positioning information provided by its own GNSS (Global Navigation Satellite System) module, while the public delay, that is, the round-trip delay from the satellite to the reference point RP on the feeder link, is usually determined by the relevant public delay parameters provided by the network. In the current 5G protocol, it is generally determined by setting the parameters The fixed time delay from the ground gateway to the reference point RP and the common time delay from the satellite to the reference point RP are described by using ta-Info (Timing Advance Information) and ta-Info (Timing Advance Information). For NGSO (Non-GeoStationary Orbit) satellites, the common time delay is time-varying because the satellite motion relative to the ground reference is always changing. The 5G system uses a second-order function with time as the independent variable to describe the common time delay over a period of time. changes, namely:

[0052]

[0053] in, 、 and They represent the 0th-order constant coefficient, the 1st-order drift rate coefficient, and the 2nd-order drift rate coefficient of the common delay, and are represented by the sub-parameters ta-Common, ta-CommonDrift, and ta-CommonDriftVariant contained in ta-Info, respectively. Indicates the starting epoch time when the function takes effect. is the corresponding time point for evaluating the common delay.

[0054] However, the prior art lacks a public analysis algorithm for the derivation and determination of common delay parameters, and the base station is unable to accurately determine the common delay parameters, resulting in the inability of subsequent user terminals to accurately estimate and compensate for the delay of the feeder link.

[0055] Based on this, in order to solve the above technical problems, the present application provides a method for determining NTN feeder link delay parameters, such as Figure 6 As shown, Figure 6 This is a flowchart of a method for determining NTN feeder link delay parameters provided in this application. The method for determining NTN feeder link delay parameters provided in this application is executed by a base station and includes the following steps:

[0056] Step 101: Determine the ephemeris information of the service satellite and the corresponding epoch time in real time during a detection period.

[0057] In this application, the user needs to pre-set the detection period, where the detection period is a period of time used to collect the ephemeris information of the service satellite and the corresponding epoch time. The base station needs to cyclically enter the detection period, which can be continuous or discontinuous. In addition, the length of the detection period can be set according to actual needs. For example, the detection period can be set to 10 minutes or 30 minutes, etc., which is not specifically limited in this application. For example, the length of the detection period is 30 minutes and the detection period is continuous. Assuming that the start time of the first detection period is 00:00, then [00:00-00:30] is the first detection period, (00:30-01:00] is the second detection period, (01:00-01:30] is the third detection period..., and so on for subsequent detection periods, and the base station cyclically enters the detection period. In each detection period, the base station needs to determine the ephemeris information and the corresponding epoch time of the service satellite in real time. Among them, the ephemeris information is expressed in terms of the orbital parameters of the satellite, and includes the following parameters:

[0058] (1) Semi-major axis of elliptical orbit , is half the length of the longest line segment that passes through the focus and intersects the ellipse;

[0059] (2) Eccentricity of elliptical orbit , is the ratio of the semi-focal length to the semi-major axis;

[0060] (3) Orbital inclination (inclination), a parameter that describes the inclination of the orbital plane relative to the reference plane;

[0061] (4) Argument of pericenter (argument of periapsis), which measures the positional relationship between the periapsis point and the reference plane;

[0062] (5) Longitude of the ascending node (longitude of ascending node), which measures the position of the orbital plane relative to the x-axis;

[0063] (6) Anomaly , refers to the angle swept by the radial direction of a celestial body when it moves along its orbit from the perigee. In addition to the true anomaly, the partial anomaly Peace Anomaly It will also be introduced to assist in orbit calculations.

[0064] Among the above parameters, except for the anomaly angle, which changes with time, the other parameters are fixed values. The epoch time corresponds to the time point when the anomaly angle is taken.

[0065] Step 102: Determine the satellite-to-ground distance corresponding to each sample moment based on the predetermined gateway station position coordinates, ephemeris information, and epoch time. The detection period includes multiple sample moments.

[0066] In this application, the detection period includes multiple sample moments, and the interval between two adjacent sample moments is the same. For example, the interval between two adjacent sample moments can be set to 5 minutes. Assume that the start time of the detection period is , the interval between two sample moments is , then the detection period can be expressed as a sequence , is the sample time, where , n is the number of sample moments. At the end of each detection period, the base station needs to determine the satellite-to-ground distance corresponding to each sample moment in the detection period based on the predetermined gateway station position coordinates and the ephemeris information and epoch time determined in the detection period, wherein the gateway station position coordinates are the ECEF (Earth-Centered, Earth-Fixed) coordinates of the gateway station, which can be derived from the positioning information of the gateway station. The specific derivation process can refer to the existing technology and will not be repeated in this embodiment. The satellite-to-ground distance is the straight-line physical distance between the service satellite and the gateway station. The satellite-to-ground distance directly affects the communication delay and signal transmission quality. In one embodiment, the process of determining the satellite-to-ground distance corresponding to each sample moment includes the following steps:

[0067] Step 1021: Determine the satellite position vector corresponding to each sample time according to the ephemeris information and epoch time.

[0068] like Figure 7 As shown, Figure 7This application provides a flow chart for determining the satellite-to-ground distance corresponding to each sample moment. When determining the satellite-to-ground distance, first use the ephemeris information corresponding to the epoch time, combined with the detection period , determine the detection period The corresponding orbital parameters. Then according to the detection period The corresponding orbital parameters are used to calculate the position of the satellite in the orbital plane based on Kepler's law. The orbital plane coordinates are converted into the position in the geocentric inertial coordinate system through three rotations (ascending node right ascension, orbit inclination, and latitude angle), and the satellite position vector in the geocentric inertial coordinate system at different sample times is obtained.

[0069] Step 1022: Determine the satellite-to-ground distance corresponding to each sample time according to the satellite position vector corresponding to each sample time and the predetermined gateway position coordinates.

[0070] After determining the satellite position vector corresponding to each sample time, it is necessary to further determine the satellite-to-ground distance corresponding to each sample time based on the satellite position vector corresponding to each sample time and the predetermined gateway station position coordinates. Specifically, the satellite position vector can be converted from the Earth-centered inertial coordinate system to the Earth-centered Earth-fixed coordinate system. Then, for each sample time, the coordinate difference vector between the service satellite and the gateway station in the Earth-centered Earth-fixed coordinate system is determined, and the modulus is taken as the satellite-to-ground distance. Corresponding to the detection period The distance between the star and the earth It can be expressed as:

[0071]

[0072] in, The sample time The corresponding star-to-earth distance, .

[0073] In addition, it can be understood that the specific process of determining the satellite-to-earth distance corresponding to each sample time can also adopt existing technologies, which is not specifically limited in this embodiment.

[0074] Step 103: Perform curve fitting based on the satellite-to-ground distance corresponding to each sample time to determine the fitting coefficient of the distance-to-time function. Determine the common delay parameter of the feeder link based on the predetermined fixed delay and the fitting coefficient. The distance-to-time function is a function that characterizes how the satellite-to-ground distance changes over time.

[0075] After determining the satellite-to-earth distance corresponding to each sample moment in the detection period, it is necessary to further perform curve fitting based on the satellite-to-earth distance corresponding to each sample moment to determine the fitting coefficient of the distance-time function, wherein the distance-time function is a function that characterizes the change of the satellite-to-earth distance over time. It can be understood that each detection period corresponds to a distance-time function. There are unknown fitting coefficients in the initial distance-time function. By performing curve fitting on the satellite-to-earth distance corresponding to each sample moment, the specific value of the fitting coefficient in the distance-time function can be solved. In one embodiment, the satellite-to-earth distance can be curve fitted to obtain the fitting coefficient by the least squares method. In another embodiment, the satellite-to-earth distance can also be curve fitted to obtain the fitting coefficient by the gradient descent method. This application takes the least squares method to obtain the fitting coefficient by curve fitting on the satellite-to-earth distance as an example, assuming that the distance-time function is a second-order function, and its specific expression is: , where the fitting coefficients include 、 and , are the zero-order coefficient, the first-order coefficient, and the second-order coefficient, respectively.

[0076] The above testing period Elements and distances between stars and the Earth The elements in correspond to the independent variables of the distance time function and variables (equivalent to ),in The error between the satellite-to-ground distance calculated by the distance-time function and the actual satellite-to-ground distance D for:

[0077]

[0078] Solving for the 0th-order coefficients , first-order coefficient and the second-order coefficients ,make At least, the specific process is as follows:

[0079] beg The extreme values ​​of 、 and Find the partial derivative and set it to 0:

[0080]

[0081] The following system of equations is obtained:

[0082]

[0083] After solving the system of equations, the fitting coefficients can be obtained 、 and The specific value of .

[0084] After determining the fitting coefficient of the distance-time function corresponding to the detection period, it is necessary to determine the common delay parameters of the feeder link based on the fitting coefficient and the predetermined fixed delay. For example, when the electromagnetic wave speed is constant, the propagation delay is proportional to the satellite-to-ground distance, and the propagation delay of the satellite-to-ground distance is calculated by the speed of light. Therefore, the expression of the propagation delay of the satellite-to-ground distance can be decomposed into a second-order polynomial form by propagation delay modeling. Then, the second-order polynomial of the propagation delay is substituted into the expression of the common delay, and combined with the fixed delay, the common delay parameters of the feeder link can be solved. It should be noted that the common delay is considered to be twice the satellite-to-ground distance during the solution process. Specifically, the common delay parameters include a zero-order constant coefficient, a first-order drift rate coefficient, and a second-order drift rate coefficient. In step 103, the common delay parameters of the feeder link are determined based on the predetermined fixed delay and the fitting coefficient, including:

[0085] Step 1031: Determine a zero-order constant coefficient of the feeder link according to the zero-order coefficient and a predetermined fixed delay.

[0086] Specifically, the calculation formula of the zero-order constant coefficient of the feeder link is as follows:

[0087]

[0088] in, is the zero-order constant coefficient, c is the electromagnetic wave speed ， For fixed delay 。

[0089] Step 1032: Determine the first-order drift rate coefficient of the feeder link according to the first-order coefficient.

[0090]

[0091] in, is the first-order drift rate coefficient 。

[0092] Step 1033: Determine the second-order drift rate coefficient of the feeder link according to the second-order coefficient.

[0093]

[0094] in, is the second-order drift rate coefficient.

[0095] Alternatively, the fitting coefficients and fixed delays can be input into a pre-built deep learning neural network, which can then output the common delay parameters of the feeder link. For example, a fully connected network can be used for deep learning neural networks. The fully connected network is suitable for structured inputs (fitting coefficients + fixed delays) and is mapped to the delay parameter space through multi-layer nonlinear transformations. When constructing the training set, the satellite-to-ground distance data can be generated based on the satellite orbit simulator and the fitting coefficients can be calculated. 、 and , and in the fitting coefficients 、 and The real hardware delay model (including fixed delay, zero-order constant coefficients, first-order drift rate coefficients, and second-order drift rate coefficients) is superimposed on the data to generate labeled data. The training set is then input into a fully connected network for training until the output error of the fully connected network is within a preset error range, resulting in a trained deep learning neural network. The training process for deep learning neural networks can be referenced in existing technologies and will not be further described in this embodiment.

[0096] In one embodiment, the fixed delay is predetermined in the following manner:

[0097] Step 104: Determine the minimum distance between the service satellite and the center of the Earth.

[0098] When determining the fixed delay, we first need to determine the minimum distance between the service satellite and the center of the earth (perigee), which can be determined by pre-set ephemeris information. ,in is the minimum distance, is the semi-major axis of the elliptical orbit, is the eccentricity of the elliptical orbit. For a near-circular orbit such as LEO (Low Earth Orbit), Simplify calculations.

[0099] Step 105: Determine a first distance between the gateway and the center of the earth based on the location coordinates of the gateway.

[0100] When determining the minimum distance, the first distance between the gateway station and the center of the earth must be determined based on the location coordinates of the gateway station. The specific calculation formula is as follows:

[0101]

[0102] in, is the first distance from the gateway station to the center of the earth, ( ) is the ECEF coordinate of the gateway station, which can be derived from the positioning information of the gateway station. The specific derivation process can refer to the existing technology and will not be repeated in this embodiment. In addition, considering that the gateway station is generally deployed on the ground, It can also be approximated directly using the average radius of the earth.

[0103] Step 106: Determine a minimum satellite-to-ground distance based on the minimum distance and the first distance, and determine a fixed delay based on the minimum satellite-to-ground distance.

[0104] Finally, the minimum satellite-to-ground distance can be determined based on the minimum distance and the first distance. Since the fixed time offset between the feeder reference point and the gateway station must be strictly limited, its physical constraint is that it must not exceed the speed of light propagation time corresponding to the minimum satellite-to-ground distance. Therefore, after determining the minimum satellite-to-ground distance, the fixed delay can be determined based on the minimum satellite-to-ground distance. The calculation formula for the minimum satellite-to-ground distance is as follows:

[0105]

[0106] in, is the minimum star-to-earth distance.

[0107] Specifically, the fixed delay is determined according to the minimum satellite-to-ground distance, including: determining the value range of the scheduling offset parameter according to the minimum satellite-to-ground distance and the vacuum propagation speed of electromagnetic waves. The specific calculation formula is:

[0108]

[0109] in is the scheduling offset parameter, i.e., a high-level parameter, The value unit is ms.

[0110] After that, the value of the scheduling offset parameter is determined within the value range, and the scheduling offset parameter is used Specifically, the maximum value that meets the actual communication needs can be selected as the scheduling offset parameter within the value range. The value of the scheduling offset parameter Determine the fixed delay.

[0111] After determining the common delay parameter, the base station can broadcast the NTN system information to the user terminal UE, wherein the NTN system information includes the scheduling offset parameter And ta-Info including sub-parameters ta-Common, ta-CommonDrift and ta-CommonDriftVariant, where the values ​​of ta-Common, ta-CommonDrift and ta-CommonDriftVariant are respectively 、 and It can be understood that the content of ta-Info is related to the detection period corresponding to the curve fitting, and the base station needs to determine the common delay parameter of each detection period to keep the ta-Info continuously updated.

[0112] After the user terminal UE receives the NTN system information broadcast by the base station, it can parse the ta-Info from the NTN system information and estimate the delay from the service satellite to the reference point RP based on the ta-Common, ta-CommonDrift and ta-CommonDriftVariant in the ta-Info. The calculation formula is as follows:

[0113]

[0114]

[0115] The round trip delay .

[0116] As described above, the present application provides a method for determining the delay parameters of an NTN feeder link. In the present application, the base station solves the satellite-to-ground distance corresponding to multiple sample moments of the detection period based on the ephemeris information and epoch time corresponding to the detection period, and then determines the fitting coefficient of the distance-time function corresponding to the detection period by curve fitting the satellite-to-ground distance. The common delay parameter is determined based on the fitting coefficient, thereby improving the accuracy and efficiency of determining the common delay parameter. This allows the user terminal to accurately estimate the common delay of the feeder link based on the common delay parameter and perform corresponding timing compensation to ensure signal synchronization, thus solving the technical problem in the prior art that the base station cannot accurately determine the common delay parameter. In addition, the present application can determine the changing trend of the satellite-to-ground distance over a longer period of time based on the calculation of fewer sample points, thereby ensuring the accuracy of the delay assessment with a lower computational overhead.

[0117] In addition, during the implementation of this application, it was found that the duration of the detection period and the interval between sample times would affect the performance of subsequent curve fitting, which is specifically manifested in the following two aspects:

[0118] (1) Influence of the duration of the detection period: When the duration is short, the fitted curve is closer to the actual change, but more frequent information updates are required; when the duration is long, the error of the fitted curve increases, but the overhead of information updates is small.

[0119] (2) The influence of the interval of sample time: When the interval is small, the fitting curve is closer to the actual change, but the computational cost is also greater; when the interval is large, the error of the fitting curve increases, but the computational cost is reduced. Based on this, this application provides another method for determining the delay parameters of the NTN feeder link, such as Figure 8 As shown, Figure 8 A flowchart of another method for determining NTN feeder link delay parameters provided in this application is provided. Figure 8 The method for determining the delay parameters of the NTN feeder link shown is based on the premise that the time interval between two adjacent sample moments is the same, and includes the following steps:

[0120] Step 201: Determine the ephemeris information of the service satellite and the corresponding epoch time in real time during a detection period.

[0121] Step 202: Determine the satellite-to-ground distance corresponding to each sample moment based on the predetermined gateway station position coordinates, ephemeris information, and epoch time. The detection period includes multiple sample moments.

[0122] Step 203: Perform curve fitting on the satellite-to-earth distance corresponding to each sample time by the least squares method to determine the fitting coefficient of the distance-time function, where the distance-time function is a function that characterizes the change of the satellite-to-earth distance over time.

[0123] Step 204: Determine the theoretical satellite-to-earth distance corresponding to each sample time based on the distance-time function after the fitting coefficient is determined.

[0124] In this embodiment, after curve fitting is performed on the satellite-to-earth distance to determine the fitting coefficient of the distance-time function, it is necessary to further calculate the theoretical satellite-to-earth distance corresponding to each sample time based on the distance-time function after the fitting coefficient is determined.

[0125] Step 205: Determine the mean square error based on the theoretical satellite-to-ground distance corresponding to each sample moment and the error between the satellite-to-ground distances.

[0126] After calculating the theoretical satellite-to-earth distance corresponding to each sample time, it is necessary to further determine the error between the theoretical satellite-to-earth distance corresponding to each sample time and the satellite-to-earth distance corresponding to each sample time determined based on the ephemeris information, and calculate the mean square error based on the error corresponding to each sample time.

[0127] Step 206: If the mean square error exceeds the preset threshold, adjust the duration of the detection period and / or the time interval between sample moments, re-determine the fitting coefficient of the distance-time function of the detection period and update the mean square error until the mean square error is within the preset threshold.

[0128] After determining the mean square error corresponding to the detection period, it can be determined whether to adjust the duration of the detection period and / or the time interval of the sample moments based on the mean square error corresponding to the detection period. Specifically, the user needs to pre-set a preset threshold range corresponding to the numerical value of the mean square error. The specific range of the preset threshold range can be determined based on experience or historical data, and is not specifically limited in this embodiment. In the case that the mean square error exceeds the preset threshold range, it is necessary to adjust the duration of the detection period and / or the time interval of the sample moments. Specifically, in the case that the mean square error is greater than the maximum value of the preset threshold range, the duration of the detection period and / or the time interval of the sample moments is reduced; in the case that the mean square error is less than the minimum value of the preset threshold range, the duration of the detection period and / or the time interval of the sample moments is increased. If the numerical value of the mean square error is within the preset threshold range, there is no need to adjust the duration of the detection period and / or the time interval of the sample moments.

[0129] After adjusting the duration of the detection period and / or the time interval between sample moments, it is necessary to re-determine the satellite-to-ground distance corresponding to each sample moment in the detection period based on the readjusted duration of the detection period and / or the time interval between sample moments, and re-perform curve fitting on the re-determined satellite-to-ground distance to re-determine the fitting coefficient of the distance-time function corresponding to the detection period. After determining the new fitting coefficient, the mean square error is calculated based on the theoretical satellite-to-ground distance determined by the new distance-time function, and it is determined whether the re-calculated mean square error is within a preset threshold range.

[0130] If the re-determined mean square error is within the preset threshold range, the subsequent steps of determining the common delay parameters can be continued based on the re-determined fitting coefficients. If the re-determined mean square error still exceeds the preset threshold range, it is necessary to further adjust the duration of the detection period and / or the time interval between sample moments, re-determine the fitting coefficients of the distance-time function for the detection period, and update the mean square error. This cycle will be repeated until the mean square error is within the preset threshold range.

[0131] Step 207: Determine the common delay parameter of the feeder link according to the predetermined fixed delay and fitting coefficient.

[0132] As described above, the method for determining NTN feeder link delay parameters provided by the present application, after curve fitting the satellite-to-ground distance corresponding to the detection period to determine the fitting coefficient of the distance-time function, needs to further determine the mean square error between the theoretical satellite-to-ground distance calculated by the distance-time function and the actual satellite-to-ground distance. If the mean square error is within a preset threshold range, the common delay parameter can be determined based on the fitting coefficient. If the mean square error exceeds the preset threshold range, it is necessary to adjust the duration of the detection period and / or the time interval between sample moments and recalculate the mean square error until the mean square error is within the preset threshold range. The present application further improves the accuracy of determining the common delay parameter by adjusting the duration of the detection period and / or the time interval between sample moments based on the mean square error between the theoretical satellite-to-ground distance and the actual satellite-to-ground distance and recalculating the fitting coefficient, enabling subsequent user terminals to accurately estimate the common delay of the feeder link based on the common delay parameter.

[0133] The present application also provides a device for determining NTN feeder link delay parameters, such as Figure 9 As shown, Figure 9 This is a schematic diagram of the structure of an NTN feeder link delay parameter determination device provided in this application. The NTN feeder link delay parameter determination device provided in this application is applicable to a base station, including:

[0134] The ephemeris information acquisition module 301 is used to determine the ephemeris information of the service satellite and the corresponding epoch time in real time during the detection period;

[0135] A satellite-to-ground distance determination module 302 is configured to determine the satellite-to-ground distance corresponding to each sample moment based on predetermined gateway location coordinates, ephemeris information, and epoch time. The detection period includes multiple sample moments.

[0136] The delay parameter determination module 303 is configured to perform curve fitting based on the satellite-to-ground distance corresponding to each sample time, determine the fitting coefficient of the distance-to-time function, and determine the common delay parameter of the feeder link based on the predetermined fixed delay and the fitting coefficient. The distance-to-time function is a function that represents the change in the satellite-to-ground distance over time.

[0137] The distance-time function is a second-order function, the fitting coefficients include a zero-order coefficient, a first-order coefficient, and a second-order coefficient, the common delay parameters include a zero-order constant coefficient, a first-order drift rate coefficient, and a second-order drift rate coefficient, and the delay parameter determination module 303 includes:

[0138] a zero-order constant coefficient determining unit, configured to determine a zero-order constant coefficient of the feeder link according to the zero-order coefficient and a predetermined fixed time delay;

[0139] a first-order drift rate coefficient determining unit, configured to determine a first-order drift rate coefficient of a feeder link according to the first-order coefficient;

[0140] The second-order drift rate coefficient determining unit is used to determine the second-order drift rate coefficient of the feeder link according to the second-order coefficient.

[0141] The time intervals between two adjacent sample moments are the same, and the delay parameter determination module 303 includes:

[0142] The curve fitting unit is used to perform curve fitting on the satellite-to-ground distance corresponding to each sample moment using the least squares method to determine the fitting coefficient of the distance-time function;

[0143] The theoretical distance determination unit is used to determine the theoretical satellite-to-earth distance corresponding to each sample moment based on the distance-time function after the fitting coefficient is determined;

[0144] A mean square error calculation unit is used to determine the mean square error based on the theoretical satellite-to-ground distance corresponding to each sample moment and the error between the satellite-to-ground distances;

[0145] The mean square error updating unit is used to adjust the duration of the detection period and / or the time interval of the sample moments when the mean square error exceeds the preset threshold range, re-determine the fitting coefficient of the distance time function of the detection period and update the mean square error until the mean square error is within the preset threshold range.

[0146] Among them, the mean square error updating unit is specifically used to reduce the duration of the detection period and / or the time interval of the sample moments when the mean square error is greater than the maximum value of the preset threshold range; and increase the duration of the detection period and / or the time interval of the sample moments when the mean square error is less than the minimum value of the preset threshold range.

[0147] It also includes a fixed delay determination module, which is used to determine the minimum distance from the service satellite to the center of the earth; determine the first distance between the gateway station and the center of the earth based on the location coordinates of the gateway station; determine the minimum satellite-to-earth distance based on the minimum distance and the first distance, and determine the fixed delay based on the minimum satellite-to-earth distance.

[0148] Among them, the fixed delay determination module is specifically used to determine the value range of the scheduling offset parameter based on the minimum satellite-to-ground distance and the vacuum propagation speed of electromagnetic waves; determine the value of the scheduling offset parameter within the value range, and determine the fixed delay based on the value of the scheduling offset parameter.

[0149] The satellite-to-ground distance determination module 302 includes:

[0150] A satellite position vector determination unit, configured to determine the satellite position vector corresponding to each sample moment based on the ephemeris information and the epoch time;

[0151] The satellite-to-ground distance determination unit is used to determine the satellite-to-ground distance corresponding to each sample moment according to the satellite position vector corresponding to each sample moment and the predetermined gateway station position coordinates.

[0152] The NTN feeder link delay parameter determination device provided in the present application is included in a base station and can be used to execute the NTN feeder link delay parameter determination method provided in the above embodiment, and has corresponding functions and beneficial effects.

[0153] It is worth noting that in the embodiment of the above-mentioned NTN feeder link delay parameter determination device, the various units and modules included are only divided according to functional logic, but are not limited to the above-mentioned division, as long as the corresponding functions can be achieved; in addition, the specific names of the functional units are only for the convenience of distinguishing each other and are not used to limit the scope of protection of the present invention.

[0154] This application also provides a base station, such as Figure 10 As shown, Figure 10 This application provides a structural diagram of a base station. The base station 40 includes: one or more processors 400; a storage device 401, configured to store one or more computer programs 402. When the one or more computer programs 402 are executed by the one or more processors 400, the one or more processors 400 implement the above-mentioned NTN feeder link delay parameter determination method.

[0155] Exemplarily, computer program 402 may be divided into one or more modules / units, one or more of which are stored in storage device 401 and executed by processor 400 to implement the present application. One or more modules / units may be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of computer program 402 in base station 40.

[0156] The base station 40 may include, but is not limited to, a processor 400 and a storage device 401. Those skilled in the art will appreciate that Figure 10 This is merely an example of the base station 40 and does not constitute a limitation on the base station 40 . The base station 40 may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the base station 40 may also include input and output devices, network access devices, buses, etc.

[0157] The processor 400 may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0158] Storage device 401 can be an internal storage unit of base station 40, such as a hard drive or memory of base station 40. Storage device 401 can also be an external storage device of base station 40, such as a plug-in hard drive, a SmartMedia Card (SMC), a Secure Digital (SD) card, a flash memory card, etc. Furthermore, storage device 401 can include both an internal storage unit of base station 40 and an external storage device. Storage device 401 is used to store computer programs and other programs and data required by base station 40. Storage device 401 can also be used to temporarily store data that has been output or is about to be output.

[0159] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0160] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interface, device or unit, which can be electrical, mechanical or other forms.

[0161] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0162] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0163] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the various embodiments of the method of the present invention. The aforementioned storage medium includes various media that can store computer programs, such as USB flash drives, mobile hard drives, read-only memory devices (ROM), random access memory devices (RAM), magnetic disks, or optical disks.

[0164] The present application also provides a non-volatile storage medium containing computer-executable instructions. When the computer-executable instructions are executed by a computer processor, the computer-executable instructions are used to perform the above-mentioned method for determining the delay parameters of the NTN feeder link. The method for determining the delay parameters of the NTN feeder link includes the following steps:

[0165] Determine the ephemeris information of the service satellite and the corresponding epoch time in real time during the detection period;

[0166] Determine the satellite-to-ground distance corresponding to each sample moment based on the predetermined gateway station location coordinates, ephemeris information, and epoch time, where the detection period includes multiple sample moments;

[0167] Curve fitting is performed based on the satellite-to-ground distance corresponding to each sample moment to determine the fitting coefficient of the distance-to-time function. Based on the predetermined fixed delay and fitting coefficient, the common delay parameter of the feeder link is determined. The distance-to-time function is a function that characterizes the change of the satellite-to-ground distance over time.

[0168] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the embodiments of the present invention are not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the embodiments of the present invention. Therefore, although the embodiments of the present invention are described in more detail through the above embodiments, the embodiments of the present invention are not limited to the above embodiments. Without departing from the concept of the embodiments of the present invention, the embodiments of the present invention may also include more other equivalent embodiments, and the scope of the embodiments of the present invention is determined by the scope of the appended claims.

Claims

1. A method for determining NTN feeder link delay parameters, characterized in that: The method is applicable to a base station, and includes: Determine the ephemeris information of the service satellite and the corresponding epoch time in real time during the detection period; Determining the satellite-to-ground distance corresponding to each sample moment according to the predetermined gateway station position coordinates, the ephemeris information, and the epoch time, wherein the detection period includes a plurality of the sample moments; Performing curve fitting based on the satellite-to-ground distance corresponding to each sample moment to determine a fitting coefficient of a distance-time function, and determining a common delay parameter of the feeder link based on a predetermined fixed delay and the fitting coefficient, wherein the distance-time function is a function that characterizes how the satellite-to-ground distance changes over time; The time intervals between two adjacent sample moments are the same, and the curve fitting is performed according to the satellite-to-ground distance corresponding to each sample moment to determine the fitting coefficient of the distance-time function, including: Performing curve fitting on the satellite-to-ground distance corresponding to each sample moment by the least squares method to determine the fitting coefficient of the distance-time function; Determining the theoretical satellite-to-earth distance corresponding to each sample moment according to the distance-time function after the fitting coefficient is determined; Determine a mean square error based on the theoretical satellite-to-ground distance corresponding to each sample moment and the error between the satellite-to-ground distances; When the mean square error exceeds a preset threshold range, the duration of the detection period and / or the time interval of the sample moments are adjusted, the fitting coefficient of the distance-time function of the detection period is re-determined, and the mean square error is updated until the mean square error is within the preset threshold range.

2. The method for determining NTN feeder link delay parameters according to claim 1, characterized in that: The distance-time function is a second-order function, the fitting coefficients include a zero-order coefficient, a first-order coefficient, and a second-order coefficient, the common delay parameters include a zero-order constant coefficient, a first-order drift rate coefficient, and a second-order drift rate coefficient, and determining the common delay parameters of the feeder link based on a predetermined fixed delay and the fitting coefficients includes: Determining a zero-order constant coefficient of the feeder link according to the zero-order coefficient and a predetermined fixed time delay; determining a first-order drift rate coefficient of the feeder link based on the first-order coefficient; A second-order drift rate coefficient of the feeder link is determined according to the second-order coefficient.

3. The method for determining NTN feeder link delay parameters according to claim 1, wherein: The adjusting the duration of the detection period and / or the time interval of the sample moments includes: When the mean square error is greater than the maximum value of the preset threshold range, reducing the duration of the detection period and / or the time interval between the sample moments; When the mean square error is smaller than the minimum value of the preset threshold range, the duration of the detection period and / or the time interval between the sample moments are increased.

4. The method for determining NTN feeder link delay parameters according to any one of claims 1 to 3, characterized in that: The fixed delay is determined in advance by: determining a minimum distance from the service satellite to the center of the Earth; Determining a first distance between the gateway and the center of the earth according to the location coordinates of the gateway; A minimum satellite-to-ground distance is determined according to the minimum distance and the first distance, and the fixed delay is determined according to the minimum satellite-to-ground distance.

5. The method for determining NTN feeder link delay parameters according to claim 4, characterized in that: The determining the fixed delay according to the minimum satellite-to-ground distance includes: Determining a value range of a scheduling offset parameter based on the minimum satellite-to-ground distance and a vacuum propagation speed of electromagnetic waves; The value of the scheduling offset parameter is determined within the value range, and the fixed delay is determined according to the value of the scheduling offset parameter.

6. The method for determining NTN feeder link delay parameters according to claim 1, characterized in that: The determining the satellite-to-ground distance corresponding to each sample time according to the predetermined gateway station position coordinates, the ephemeris information, and the epoch time includes: Determining a satellite position vector corresponding to each sample moment according to the ephemeris information and the epoch time; The satellite-to-ground distance corresponding to each sample moment is determined based on the satellite position vector corresponding to each sample moment and the predetermined gateway position coordinates.

7. The device for determining the delay parameters of an NTN feeder link is characterized in that: The device is applicable to a base station, and includes: The ephemeris information acquisition module is used to determine the ephemeris information of the service satellite and the corresponding epoch time in real time during the detection period; a satellite-to-ground distance determination module, configured to determine the satellite-to-ground distance corresponding to each sample moment based on predetermined gateway location coordinates, the ephemeris information, and the epoch time, wherein the detection period includes a plurality of the sample moments; a delay parameter determination module, configured to perform curve fitting based on the satellite-to-ground distance corresponding to each sample moment to determine a fitting coefficient of a distance-time function, and determine a common delay parameter of the feeder link based on a predetermined fixed delay and the fitting coefficient, wherein the distance-time function is a function that characterizes the change of the satellite-to-ground distance over time; The time intervals between two adjacent sample moments are the same, and the delay parameter determination module includes: a curve fitting unit, configured to perform curve fitting on the satellite-to-ground distance corresponding to each sample moment by a least squares method, and determine a fitting coefficient of a distance-time function; a theoretical distance determination unit, configured to determine the theoretical satellite-to-earth distance corresponding to each sample moment according to the distance-time function after the fitting coefficient is determined; a mean square error calculation unit, configured to determine a mean square error based on a theoretical satellite-to-ground distance corresponding to each sample moment and an error between the satellite-to-ground distances; A mean square error updating unit is configured to adjust the duration of the detection period and / or the time interval between the sample moments when the mean square error exceeds a preset threshold range, re-determine the fitting coefficient of the distance-time function of the detection period, and update the mean square error until the mean square error is within the preset threshold range.

8. A base station, characterized in that: The base station includes: one or more processors; a storage device configured to store one or more programs, and when the one or more programs are executed by the one or more processors, the one or more processors implement the NTN feeder link delay parameter determination method according to any one of claims 1 to 6.

9. A non-volatile storage medium storing computer executable instructions, characterized in that: When executed by a computer processor, the computer executable instructions are configured to execute the method for determining NTN feeder link delay parameters according to any one of claims 1 to 6.

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