Handover selection method, apparatus, and electronic device

Abstract

The application discloses a switching selection method and device and electronic equipment, which can be applied to the technical field of satellite communication. The method comprises the following steps: acquiring a first service period in which a source satellite can provide services for a user terminal and a plurality of second service periods in which a plurality of candidate satellites can provide services for the user terminal; determining target switching times corresponding to each candidate satellite in the plurality of candidate satellites based on the first service period and the plurality of second service periods; determining satellite switching costs of switching from the source satellite to each candidate satellite based on the target switching times, and determining a target satellite corresponding to the switching of the source satellite from the plurality of candidate satellites based on the satellite switching costs corresponding to each candidate satellite. Based on the above method, the related data processing process can be effectively simplified, the target satellite corresponding to the switching of the source satellite can be quickly determined in a short time, and the switching selection can be quickly and efficiently realized.

Description

Technical Field

[0001] This application relates to the field of satellite communication technology, and in particular to a satellite switching method, apparatus and electronic equipment. Background Technology

[0002] In satellite-based wireless communication scenarios, in order to ensure that user equipment can communicate normally, user equipment sometimes needs to switch from one satellite (i.e., the source satellite) to another satellite (i.e., the target satellite). In this process, the selection of the target satellite is crucial for wireless communication after the satellite handover.

[0003] Currently, when switching satellites, the target satellite is usually selected from multiple candidate satellites. This often requires real-time acquisition of a large amount of information related to the user terminal and the satellite. The overall information processing is quite complex, requires high computing power, and takes a long time.

[0004] There is currently no effective solution to the problem of not being able to quickly and efficiently switch between star selections. Summary of the Invention

[0005] The purpose of this application is to provide a method, apparatus, and electronic device for switching satellites, which can effectively simplify the relevant data processing process, have low computing power requirements, and can quickly and efficiently achieve satellite switching.

[0006] The first aspect of this manual provides a method for switching star selection, including:

[0007] The first service period during which the source satellite can provide services to the user terminal and the second service period during which multiple alternative satellites can provide services to the user terminal are obtained.

[0008] Based on the first service period and multiple second service periods, a reference switching time corresponding to multiple candidate satellites is determined, and based on the reference switching time and the orbital data of each candidate satellite, a target switching time corresponding to each candidate satellite is determined.

[0009] The satellite handover cost from the source satellite to each candidate satellite is determined based on the handover time of each target and at least one indicator related to measuring the quality of satellite service. Based on the satellite handover cost corresponding to each candidate satellite, the target satellite corresponding to the source satellite is determined from multiple candidate satellites.

[0010] The satellite switching cost is used to characterize the cost incurred when a user terminal switches from the source satellite to each of the alternative satellites.

[0011] In some embodiments of this specification, the candidate satellites are satellites that share a common coverage period with the source satellite, and the target switching time corresponding to each candidate satellite is determined in the following way:

[0012] Determine the overpass time of the source star;

[0013] Based on the second service period and the overhead time, the reference handover time corresponding to the candidate satellite is determined;

[0014] The user terminal determines the angle difference between the orbital plane of the candidate satellite and the candidate satellite at the reference handover time.

[0015] The angular velocity of the candidate satellite at the reference switching time is determined, and the target switching time corresponding to the candidate satellite is determined based on the angular velocity, the angle difference, and the reference switching time.

[0016] In some embodiments of this specification, the angle difference includes at least one of the following: latitude argument angle difference, true near angle angle difference, deviated near angle angle difference, flat near angle angle difference, and perigee argument angle difference.

[0017] In some embodiments of this specification, the reference handover time corresponding to the candidate satellite is determined based on the second service period and the overpass time, including:

[0018] Based on the second service period, determine the initial time when the candidate satellite can provide services to the user terminal;

[0019] When the initial time is less than the overpass time, the reference switching time is the overpass time; otherwise, the reference switching time is the initial time.

[0020] In some embodiments of this specification, determining the target switching time corresponding to the candidate satellite based on the angular velocity, the angular difference, and the reference switching time includes:

[0021] Based on the angle difference and the angular velocity, determine the first time interval for the candidate satellite to move from the reference position corresponding to the reference switching time to the overpass position;

[0022] The target switching time is determined based on the first duration and the reference switching time.

[0023] In some embodiments of this specification, the target switching time is determined by the following formula:

[0024] ;

[0025] in, t ref Indicates the target switching time. t init Indicates the reference switching time, This represents the first angle of the candidate satellite in its orbital plane at the reference switching time. This represents the second angle of the user terminal in the orbital plane of the alternative satellite at the reference handover time. u A ( t init ) represents the angular velocity of the candidate satellite at the reference switching time.

[0026] In some embodiments of this specification, the satellite handover cost corresponding to each candidate satellite is determined in the following manner:

[0027] Determine the overpass time of the source satellite, and based on the overpass time and the first service period, determine the first remaining service duration that the source satellite can provide services to the user terminal after its overpass.

[0028] Based on the second service period and the overhead time, the reference handover time corresponding to the candidate satellite is determined;

[0029] Based on the second service period and the reference switching time, determine the second remaining service duration that the alternative satellite can provide services to the user terminal after switching to the alternative satellite;

[0030] Based on the first remaining service duration and the second remaining service duration, the satellite selection duration cost corresponding to the candidate satellite is determined, and the satellite selection duration cost is used as the satellite switching cost corresponding to the candidate satellite.

[0031] In some embodiments of this specification, the satellite selection time cost corresponding to the candidate satellite is determined based on the first remaining service time and the second remaining service time, including:

[0032] A first ratio of the second remaining service duration to the first remaining service duration is determined, and the first ratio is processed based on a preset normalization algorithm to obtain the star selection duration cost.

[0033] In some embodiments of this specification, the cost of star selection time is determined by the following formula:

[0034] J T = -log a ( L t A / L t S );

[0035] in, J TThe time cost of star selection is represented by -log a (·) indicates a preset normalization algorithm. L t A This indicates the second remaining service duration. L t S This indicates the first remaining service duration.

[0036] In some embodiments of this specification, the satellite handover cost corresponding to each candidate satellite is determined in the following manner:

[0037] The shortest distance between the source satellite and the user terminal is determined as the first distance;

[0038] Determine the first position of the candidate satellite and the second position of the user terminal at the target switching time;

[0039] Based on the first location and the second location, a second distance between the candidate satellite and the user terminal is determined;

[0040] Based on the first distance and the second distance, the satellite selection distance cost corresponding to the candidate satellite is determined, and the satellite selection distance cost is used as the satellite switching cost corresponding to the candidate satellite.

[0041] In some embodiments of this specification, determining the first location of the candidate satellite and the second location of the user terminal at the target handover time includes:

[0042] Obtain the orbital parameters of the orbital plane where the candidate satellite is located and the second position;

[0043] Based on the orbital parameters, determine the second angle of the candidate satellite in its orbital plane at the target switching time;

[0044] The first position is determined based on the second angle.

[0045] In some embodiments of this specification, the satellite selection distance cost corresponding to the candidate satellite is determined based on the first distance and the second distance, including:

[0046] Determine a second ratio between the first distance and the second distance;

[0047] Determine the communication loss corresponding to the second ratio, and determine the communication loss as the cost of the satellite selection distance.

[0048] In some embodiments of this specification, the star selection distance cost is determined by the following formula:

[0049] ;

[0050] in, J L Indicates the cost of star selection distance. α Gain coefficient representing communication quality and communication distance. D Indicates the first distance. X 2 AU + Y 2 AU + Z 2 AU This represents the square of the second distance.

[0051] In some embodiments of this specification, the satellite handover cost corresponding to each candidate satellite is determined in the following manner:

[0052] Determine the overpass time of the source satellite, and based on the overpass time and the first service period, determine the first remaining service duration that the source satellite can provide services to the user terminal after its overpass.

[0053] Based on the second service period and the overhead time, determine the second remaining service duration that the alternative satellite can provide services to the user terminal after switching the alternative satellite;

[0054] Based on the first remaining service time and the second remaining service time, the satellite selection time cost corresponding to the candidate satellite is determined;

[0055] The shortest distance between the source satellite and the user terminal is determined as the first distance;

[0056] Determine the first position of the candidate satellite and the second position of the user terminal at the target switching time, and determine the second distance between the candidate satellite and the user terminal based on the first position and the second position;

[0057] Based on the first distance and the second distance, determine the satellite selection distance cost corresponding to the candidate satellite;

[0058] The satellite switching cost is determined based on the satellite selection time cost and the satellite selection distance cost.

[0059] In some embodiments of this specification, the satellite switching cost is determined based on the satellite selection duration cost and the satellite selection distance cost, including:

[0060] Obtain the first weight coefficient corresponding to the star selection time cost and the second weight coefficient corresponding to the star selection distance cost;

[0061] Based on the first weighting coefficient and the second weighting coefficient, the satellite selection duration cost and the satellite selection distance cost are weighted and summed to obtain the satellite switching cost.

[0062] In some embodiments of this specification, the target satellite for switching the source satellite is determined from multiple candidate satellites based on the satellite switching cost corresponding to each candidate satellite, including:

[0063] The candidate satellite with the lowest satellite switching cost among multiple candidate satellites is determined as the target satellite.

[0064] In some embodiments of this specification, the target satellite for switching the source satellite is determined from multiple candidate satellites based on the satellite switching cost corresponding to each candidate satellite, including:

[0065] The candidate satellites are sorted based on the satellite switching cost corresponding to each candidate satellite;

[0066] Based on the ranking results, a target number of satellites are selected as candidate satellites from the multiple alternative satellites.

[0067] Based on preset screening criteria, a target number of candidate satellites are screened, and the candidate satellite with the lowest satellite switching cost is determined as the target satellite from the screening results.

[0068] In some embodiments of this specification, it is applied to the source star-borne base station.

[0069] The second aspect of this specification provides a satellite selection switching device, comprising:

[0070] The acquisition module is used to acquire the first service period during which the source satellite can provide services to the user terminal and the second service period during which multiple alternative satellites can provide services to the user terminal.

[0071] The determination module is used to determine the reference switching time corresponding to multiple candidate satellites based on the first service period and multiple second service periods, and to determine the target switching time corresponding to each candidate satellite based on the reference switching time and the orbital data of each candidate satellite.

[0072] The selection module is used to determine the target switching time corresponding to each candidate satellite based on the target switching time, the reference switching time, and the orbital data of each candidate satellite, determine the satellite switching cost from the source satellite to each candidate satellite, and determine the target satellite corresponding to the source satellite from multiple candidate satellites based on the satellite switching cost corresponding to each candidate satellite.

[0073] The satellite switching cost is used to characterize the cost incurred when a user terminal switches from the source satellite to each of the alternative satellites.

[0074] A third aspect of this specification provides an electronic device including a processor and a memory for storing processor-executable instructions, wherein the processor, when executing the instructions, implements the steps of the method described in the first aspect.

[0075] A fourth aspect of this specification provides a computer storage medium storing computer program instructions that, when executed by a processor, implement the steps of the method described in the first aspect.

[0076] A fifth aspect of this specification provides a computer program product comprising a computer program that, when executed by a processor, implements the steps of the method described in the first aspect.

[0077] The satellite switching selection method, apparatus, and electronic equipment described in this specification acquire a first service period during which the source satellite can provide services to the user terminal and a second service period during which multiple candidate satellites can provide services to the user terminal. Based on the first service period and the multiple second service periods, a reference switching time corresponding to multiple candidate satellites is determined. Based on the reference switching time and the orbital data of each candidate satellite, a target switching time corresponding to each candidate satellite is determined. Based on each target switching time and at least one indicator related to measuring satellite service quality, the satellite switching cost from the source satellite to each candidate satellite is determined. Based on the satellite switching cost corresponding to each candidate satellite, the target satellite corresponding to the source satellite for switching is determined from among the multiple candidate satellites. In this specification embodiment, by using the service periods of the source satellite and multiple candidate satellites, the target switching time applicable to each candidate satellite can be quickly determined. Then, based on the target switching time, the satellite switching cost from the source satellite to each candidate satellite is calculated, and the target satellite to be switched is determined. This method has low computing power requirements and can be applied to various communication scenarios such as onboard or resource-constrained environments. Furthermore, it can effectively simplify the relevant data processing process and quickly determine the target satellite corresponding to the source satellite for switching in a short time, achieving fast and efficient satellite switching selection. Attached Figure Description

[0078] To more clearly illustrate the technical solutions in the embodiments of this application 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 only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0079] Figure 1 The diagram shown is a schematic representation of a satellite-based communication scenario provided in an embodiment of this specification.

[0080] Figure 2The diagram shown is a schematic representation of the star selection switching method provided in the embodiments of this specification.

[0081] Figure 3 The diagram shown is a schematic representation of a method for determining the target switching time provided in an embodiment of this specification.

[0082] Figure 4 The diagram shown is a schematic representation of the satellite coverage area provided in an embodiment of this specification.

[0083] Figure 5 The diagram shown is a schematic representation of the satellite coverage area provided in an embodiment of this specification.

[0084] Figure 6 The diagram shown is a schematic representation of a method for determining satellite handover costs provided in an embodiment of this specification.

[0085] Figure 7 The diagram shown is a schematic representation of a method for determining satellite handover costs provided in an embodiment of this specification.

[0086] Figure 8 The diagram shown is a schematic representation of a method for determining satellite handover costs provided in an embodiment of this specification.

[0087] Figure 9 The diagram shown is a schematic of a satellite selection switching device provided in an embodiment of this specification.

[0088] Figure 10 The diagram shown is a schematic of an electronic device provided in an embodiment of this specification. Detailed Implementation

[0089] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0090] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0091] This specification provides the operational steps of the methods described in the embodiments or flowcharts, but based on conventional or non-inventive labor, more or fewer operational steps may be included. The order of steps listed in the embodiments is merely one possible execution order among many and does not represent the only possible execution order. In actual system or device products, the methods shown in the embodiments or drawings can be executed sequentially or in parallel.

[0092] It should be noted that the information involved in this application (including but not limited to user terminal device information, user personal information, etc.) is all information and data authorized by the user or fully authorized by all parties, and the acquisition, transmission, storage, use and processing of the relevant data comply with the relevant laws, regulations and standards of the relevant countries and regions.

[0093] It should be noted that in the embodiments of this specification, certain software, components, models and other existing solutions in the industry may be mentioned. These should be regarded as exemplary and are only intended to illustrate the feasibility of implementing the technical solution of the present invention. However, they do not mean that the applicant has used or necessarily used such solutions.

[0094] refer to Figure 1 As shown, in a satellite-based communication scenario, a communication link is established between the satellite and the user terminal (UE) to connect the UE to the satellite, thus enabling satellite-based wireless communication. The satellite currently connected to the UE can be designated as the source satellite (S). While the source satellite S provides services to the UE, changes in satellite or UE movement may cause the UE to leave the communication coverage area of ​​the source satellite S, or the source satellite S may no longer be the optimal choice for the UE. In such cases, another satellite capable of providing services to the UE can be selected, i.e., the target satellite, and the UE's communication link can be switched from the source satellite S to the target satellite. The selection of the target satellite during this satellite switching process is crucial for maintaining UE communication subsequently.

[0095] The source satellite and alternative satellites can be stationary satellites, etc. A stationary satellite can be specifically understood as a satellite that stays in a specific orbital position or area for a long period of time to perform specific tasks. This satellite can typically operate stably at the target position for extended periods to continuously provide services or monitor a specific area. It should be noted that the source satellite and alternative satellites can also be other types of satellites; this specification does not impose any restrictions on this.

[0096] The user equipment can be a mobile phone, a tablet computer, a satellite phone, etc. It should be noted that the user equipment listed above is only illustrative. In actual implementation, depending on the specific application scenario and processing requirements, the user equipment can be other types of electronic devices; this specification does not limit this.

[0097] In some embodiments, the target satellite is typically selected from multiple candidate satellites by calculating their communication resources, such as bandwidth margin, power margin, resource rate, and routing hop count. However, the process of determining the target satellite based on the communication resources of each candidate satellite requires obtaining the current status information of all candidate satellites and the user terminal, resulting in a large amount of data, cumbersome data processing, high computing power requirements, and longer processing time.

[0098] Considering that satellite-based communication systems require a relatively long service duration after handover to reduce handover frequency and operational load, while simultaneously ensuring communication quality as much as possible, for other satellites, such as candidate satellites A, B, and C, assuming consistent polarization loss and atmospheric loss, equal probability of cloud, fog, and rain attenuation, negligible demodulation loss differences, and equal probabilities of obstruction and interference, the main factors affecting communication quality are free space loss and user terminal scanning loss. Both free space loss and user terminal scanning loss are strongly correlated with the distance between the satellite and the UE. Therefore, this specification proposes an embodiment that enables fast and efficient satellite selection by using changes in satellite service duration and communication distance before and after handover as the satellite handover cost to quantify each candidate satellite and achieve target satellite selection. Specifically... By utilizing the service periods of the source satellite and multiple alternative satellites, the target switching time applicable to each alternative satellite can be quickly determined. Then, based on the target switching time, the satellite switching cost from the source satellite to each alternative satellite can be calculated, and the target satellite to be switched to can be determined. This method has low computing power requirements and can be applied to various communication scenarios such as onboard or resource-constrained environments. Furthermore, it can effectively simplify the relevant data processing process and quickly determine the target satellite corresponding to the source satellite for switching in a short period of time, achieving fast and efficient satellite selection for switching.

[0099] It is understood that the method described above for quantifying the switching costs of each alternative satellite based on factors such as satellite service duration and communication quality to user terminals is only one example of this specification. In other embodiments, the satellite switching cost may include more or fewer satellite service quality-related factors than those described above, and this specification does not limit this.

[0100] Based on this, embodiments of this specification provide a satellite handover selection method. It is understood that the satellite handover selection method provided in these embodiments can be specifically applied to the user equipment side. The user equipment can calculate the satellite handover cost from the source satellite to each candidate satellite based on the above-described satellite handover selection method, and determine the target satellite corresponding to the source satellite among multiple candidate satellites based on the satellite handover cost. The satellite handover selection method provided in these embodiments can also be applied to the satellite side (e.g., the source satellite's onboard base station), or the server side of a satellite communication service platform, etc. Correspondingly, the satellite or server can calculate the satellite handover cost from the source satellite to each candidate satellite based on the above-described satellite handover selection method, and determine the target satellite corresponding to the source satellite among multiple candidate satellites based on the satellite handover cost. Figure 2 The diagram shown is a schematic representation of the satellite selection switching method provided in an embodiment of this specification. Figure 2 As shown, this method for switching star selection can include:

[0101] S201: Obtain the first service period during which the source satellite can provide services to the user terminal, and the second service period during which multiple alternative satellites can provide services to the user terminal.

[0102] In this context, the source satellite can be the satellite currently accessed by the user equipment. The candidate satellites can be at least some of the satellites in the satellite network other than the source satellite. Therefore, satellites with shared coverage time with the source satellite can be selected from among multiple candidate satellites as candidate satellites for subsequent handover selection. Candidate satellites can also be neighboring satellites of the source satellite in the satellite network, sharing shared coverage time with the source satellite. That is, in the embodiments of this specification, the candidate satellites participating in subsequent handover selection need to share shared coverage time with the source satellite to ensure the continuity of satellite-based communication services.

[0103] The first service period can be defined as the visible period of the source satellite relative to the user terminal, during which the source satellite can provide services to the user terminal. Specifically, during its operation, the source satellite generally moves along a specific orbit around the Earth's center. During this process, due to the relative position of the source satellite and the user terminal, the signal reception range of the user terminal's antenna, and the wavenumber coverage range of the source satellite, the source satellite is visible to the user terminal within a certain spatial range. Furthermore, due to the movement of the source satellite and the user terminal, the visibility of the source satellite relative to the user terminal can be defined as being visible within a certain time range (i.e., a time period), during which the source satellite can provide services to the user terminal. For example, the first service period can be obtained in the following way: obtain the orbit data of the source satellite, the location of the user terminal, the beam-related limitations of the source satellite (e.g., the maximum off-axis angle of the beam, which can be determined based on the phased array or antenna of the source satellite) and the transmit and receive limitations of the antenna of the user terminal (e.g., the minimum operating elevation angle of the antenna of the user terminal), transform the orbit data of the source satellite and the location of the user terminal to the same coordinate system, and based on the transformed orbit data, determine the period in which the user terminal meets its corresponding elevation angle threshold and the source satellite meets its corresponding beam off-axis angle threshold as the first service period corresponding to the source satellite.

[0104] Similarly, the second service period can be the period during which the alternative satellite is visible to the user terminal, during which the alternative satellite can provide services to the user terminal, and the second service period can be determined using a method similar to that used for the first service period.

[0105] S202: Based on the first service period and multiple second service periods, determine the reference switching time corresponding to multiple candidate satellites, and based on the reference switching time and the orbital data of each candidate satellite, determine the target switching time corresponding to each candidate satellite.

[0106] The target handover time can be understood as the time required to switch the user terminal's access to a satellite from the source satellite to a candidate satellite. Each candidate satellite has a corresponding target handover time. This target handover time is not necessarily used for subsequent satellite handovers, but rather for calculating the handover cost of subsequent satellite handovers, thereby enabling the selection of the target satellite from multiple candidate satellites. When a satellite handover is required later, it can be performed based on the target handover time corresponding to the target satellite.

[0107] S203: Determine the satellite handover cost from the source satellite to each candidate satellite based on the handover time of each target and at least one indicator related to measuring satellite service quality, and determine the target satellite corresponding to the source satellite from among the multiple candidate satellites based on the satellite handover cost corresponding to each candidate satellite.

[0108] Satellite handover cost can be understood as the cost of switching a user terminal's access to a satellite from the source satellite to various candidate satellites. Satellite handover cost can serve as a quantifiable indicator, intuitively reflecting the expenses incurred in switching from the source satellite to each candidate satellite. This effectively transforms the complex satellite selection process into an efficient and quantifiable cost calculation, simplifying the calculation process. Satellite handover cost can be calculated based on at least one indicator related to satellite service quality. Measuring satellite service quality can include, for example, satellite handover frequency, communication quality, and satellite status. For instance, satellite handover frequency can be characterized by satellite coverage duration (i.e., the duration for which the satellite can continue to provide services to the user terminal), communication quality can be characterized by free-space fading loss, and satellite status can be characterized by the communication resources the satellite can provide to the user terminal. Furthermore, the corresponding handover cost can be calculated based on at least one aspect of satellite coverage duration, free-space fading loss, and satellite communication resources, thus obtaining the satellite handover cost based on at least one aspect of the handover cost. In other embodiments, satellite handover costs may also include other metrics related to measuring satellite service quality. The algorithm model for satellite handover costs can be customized and extended to adapt to different application scenarios and application requirements, thus achieving higher scalability.

[0109] In the embodiments described in this specification, by utilizing the service periods of the source satellite and multiple candidate satellites, the target handover time applicable to each candidate satellite can be quickly determined. Then, the satellite handover cost from the source satellite to each candidate satellite is calculated using the target handover time, and the target satellite to be handed over is determined. This method has low computational requirements, making it suitable not only for scenarios with abundant computing resources, reducing resource utilization, but also for various communication scenarios such as onboard or resource-constrained environments, improving the applicability of the aforementioned handover satellite selection method. Furthermore, the method of calculating the target handover time and then the satellite handover cost through the service period effectively simplifies the data processing process, enabling rapid determination of the target satellite corresponding to the source satellite for handover within a short time, achieving fast and efficient handover satellite selection, improving the handover satellite selection speed, and meeting high real-time requirements.

[0110] The satellite selection method described in the embodiments of this specification can be implemented when the user terminal is connected to the source satellite, when the user triggers a satellite selection command / satellite switching command, or when the source satellite is determined to be unable to continue providing services to the user terminal, and is implemented upon receiving the satellite switching command. That is, the process of determining the target satellite can be implemented at any time before satellite switching, and this specification does not impose any restrictions on this.

[0111] refer to Figure 3As shown, in some embodiments of this specification, the candidate satellites are satellites that share a common coverage period with the source satellite, and the target switching time corresponding to each candidate satellite can be determined in the following ways:

[0112] S301: Determine the overpass time of the source star.

[0113] S302: Based on the second service period and the overhead time, determine the reference switching time corresponding to the candidate satellite.

[0114] S303: Determine the angle difference between the orbital plane of the candidate satellite and the candidate satellite at the reference handover time.

[0115] S304: Determine the angular velocity of the candidate satellite at the reference switching time, and based on the angular velocity, the angle difference, and the reference switching time, determine the target switching time corresponding to the candidate satellite.

[0116] The overpass time is the moment when the satellite is closest to the user terminal. At this time, the satellite's nadir point coincides with or is closest to the user terminal's position. The communication link quality between the satellite and the user terminal is optimal at the overpass time. The reference handover time can be understood as the handover time applicable to multiple candidate satellites. For example, the overpass time can be determined by obtaining the source satellite's orbital data and the user terminal's position, and converting the source satellite's orbital data and the user terminal's position to the same coordinate system, thus determining the moment when the user terminal is closest to the source satellite; or, based on the source satellite's orbital data, the user terminal's position, and the Earth's center position in the same coordinate system, determining the moment when the user terminal, the source satellite, and the Earth's center are aligned on a straight line; or, during the calculation of the service period that the source satellite can provide to the user terminal, determining the moment corresponding to the maximum operating elevation angle of the user terminal's antenna within the corresponding service period. For example, the angular velocity can be determined by obtaining the orbital data of the candidate satellites and finding their angular velocities at the reference handover time within the angular data contained in their orbital data.

[0117] The angle difference can be understood as the difference in angle between the user equipment and the candidate satellite in the orbital coordinate system based on the candidate satellite's orbital plane. Specifically, at the reference handover time, the first angle of the candidate satellite in its orbital plane and the second angle of the user terminal based on the candidate satellite's orbital plane can be determined separately. The difference between the first angle and the second angle can be used as the aforementioned angle difference. The first angle can be determined based on the candidate satellite's ephemeris information, and the second angle can be determined based on the user terminal's position.

[0118] In some embodiments of this specification, the angle difference may include at least one of the following: latitude argument angle difference, true aperiod angle difference, deviated aperiod angle difference, mean aperiod angle difference, and perigee argument angle difference. It is understood that the angle difference can be any of the above angle differences, or a combination of at least two of the above angle differences.

[0119] Accordingly, the first angle and the second angle can include at least one of the following: latitudinal argument, true anomaly, deviated anomaly, mean anomaly, and perigee argument. It should be noted that, to improve the accuracy of the calculation results, the first angle and the second angle are of the same type.

[0120] The true anomaly is the angle swept by the vector from the perigee (the point of closest approach to the Earth) to the satellite's position in an elliptical orbit, with the foci of the ellipse as the vertex. The elliptic anomaly is the angle formed by the line connecting the satellite's position at the observation time to the semi-major axis of the ellipse, extending this perpendicular line, and intersecting the circular orbit centered at the ellipse's center with its semi-major axis as the radius. The mean anomaly is the angle formed by the line connecting the satellite and Earth at the observation time to the perigee when the satellite is orbiting at an average angular velocity in a circular orbit that shares the same center as the elliptical orbit and has a radius equal to the semi-major axis of the ellipse. The argument of perigee is the angle observed at the foci of the elliptical orbit from the ascending node to the point of closest distance between the orbiting object and the foci. The argument of latitude can specifically refer to the sum of the argument of perigee and the true angle of aperitoneal distance.

[0121] It should be noted that the angular differences listed above are merely illustrative. In actual implementation, depending on the specific circumstances and processing requirements, the aforementioned angular differences may include other types or fewer types of angular differences, which this specification does not limit.

[0122] In some embodiments of this specification, determining the reference handover time corresponding to the candidate satellite based on the second service period and the overpass time may include: determining the initial time when the candidate satellite can provide services to the user terminal based on the second service period; when the initial time is less than the overpass time, the reference handover time is the overpass time; otherwise, the reference handover time is the initial time.

[0123] The second service period can include the initial time and the final time. The time between the initial time and the final time is when the candidate satellite can provide services to the user terminal. The overpass time can represent the moment when the source satellite is closest to the user terminal. Based on the relationship between communication distance and communication quality, it can be concluded that the closer the source satellite is to the user terminal, the higher its communication quality, and the farther the distance, the lower the communication quality. Therefore, after the source satellite overpasses, the farther the source satellite is from the user terminal, the worse its communication quality becomes; before the source satellite overpasses, the closer the source satellite is to the user terminal, the better its communication quality becomes. Let point U represent the user terminal, point S represent the source satellite, and point A represent candidate satellite A. For the user terminal, if the overpass time of the source satellite is greater than the initial time of the candidate satellite, refer to... Figure 4 As shown, since the source satellite has not yet passed overhead, the communication quality with the user terminal is gradually improving. Meanwhile, the user terminal has just entered the coverage area of ​​the alternative satellite, which is farther away and has poorer communication quality compared to the source satellite. Therefore, there is no need to switch to the alternative satellite before the source satellite passes overhead; the switch can be made after the source satellite passes overhead. The overhead time can be used as a reference switching time. Otherwise, if the overhead time of the source satellite is not greater than the initial time corresponding to the alternative satellite, the reference time should be used. Figure 5 As shown, as the source satellite moves further away from the user terminal, the alternative satellite moves closer to the terminal. The alternative satellite has better communication quality than the source satellite. Therefore, the user terminal can switch from the source satellite to the alternative satellite as soon as it enters the coverage area of ​​the alternative satellite. In this case, the initial time can be used as a reference switching time. "Less than" indicates an earlier time, and "greater than" indicates a later time.

[0124] In the embodiments of this specification, the reference switching time applicable to the alternative satellite can be quickly determined by combining the communication needs of the user terminal and the relationship between the overpass time of the source satellite and the initial time when the alternative satellite can provide services to the user terminal, while ensuring the service quality of the satellite-based communication scenario.

[0125] In some embodiments of this specification, determining the target switching time for the candidate satellite based on the angular velocity, the angular difference, and the reference switching time may include: determining a first duration for the candidate satellite to move from the reference position corresponding to the reference switching time to its overpass position based on the angular difference and the angular velocity; and determining the target switching time based on the first duration and the reference switching time. Specifically, the sum of the first duration and the reference switching time can be used as the target switching time.

[0126] In some embodiments of this specification, the target switching time can be determined by the following formula:

[0127] Formula (1)

[0128] in, t ref This can represent the target switching time. t init This can represent the reference switching time. This can represent the first angle of the candidate satellite in its orbital plane at the reference switching time. This can represent the second angle of the user terminal in the orbital plane of the alternative satellite at the reference switching time. u A ( t init ) can represent the angular velocity of the candidate satellite at the reference switching time.

[0129] In some embodiments of this specification, the satellite handover cost may include a satellite selection duration cost, which reflects the satellite handover frequency, i.e., the change in the duration during which a candidate satellite can continue to provide services to the user terminal after handover compared to the duration during which the source satellite can continue to provide services to the user terminal. The process may include: determining the overpass time of the source satellite, and based on the overpass time and a first service period, determining a first remaining service duration during which the source satellite can provide services to the user terminal after overpass; and based on a second service period and the overpass time, determining a second remaining service duration during which the candidate satellite can provide services to the user terminal after handover, provided that there is still a common coverage duration between the source and candidate satellites after the source satellite's overpass, and the candidate satellite still provides services to the user terminal; and further, determining the satellite selection duration cost corresponding to the candidate satellite based on the first and second remaining service durations.

[0130] refer to Figure 6 As shown, in some embodiments of this specification, the satellite handover cost corresponding to each candidate satellite can be determined in the following ways:

[0131] S501: Determine the overpass time of the source satellite, and based on the overpass time and the first service period, determine the first remaining service duration that the source satellite can provide services to the user terminal after its overpass.

[0132] S502: Based on the second service period and the overhead time, determine the reference switching time corresponding to the candidate satellite.

[0133] S503: Based on the second service period and the reference switching time, determine the second remaining service duration that the alternative satellite can provide services to the user terminal after switching the alternative satellite.

[0134] S504: Based on the first remaining service duration and the second remaining service duration, determine the satellite selection duration cost corresponding to the candidate satellite, and use the satellite selection duration cost as the satellite handover cost corresponding to the candidate satellite.

[0135] It is understandable that the reference handover time is after the source satellite passes overhead. Therefore, the first remaining service duration that the source satellite can provide service to the user terminal after its overhead passage can more accurately assess the satellite handover frequency based on the source satellite. Since the reference handover time is expected to be from the source satellite to the alternative satellite, the second remaining service duration that the alternative satellite can provide service to the user terminal after the reference handover time can more accurately assess the satellite handover frequency based on the alternative satellite. Furthermore, after obtaining the first and second remaining service durations, the satellite selection time cost can be calculated to quantify whether a cost is incurred in switching from the source satellite to the alternative satellite. The satellite selection time cost can characterize the duration that the alternative satellite can provide to the user terminal compared to the source satellite.

[0136] Specifically, the first remaining service duration can be the difference between the last moment when the source satellite can provide service to the user terminal and the overpass time, and the second remaining service duration can be the difference between the last moment when the alternative satellite can provide service to the user terminal and the reference handover time. It should be noted that in other embodiments, the second remaining service duration can also be determined based on the second service period and the target handover time, and this specification does not limit this.

[0137] In some embodiments of this specification, determining the satellite selection time cost corresponding to the candidate satellite based on the first remaining service time and the second remaining service time may include: determining a first ratio of the second remaining service time to the first remaining service time, and processing the first ratio based on a preset normalization algorithm to obtain the satellite selection time cost.

[0138] In the embodiments of this specification, a preset normalization algorithm processes the first ratio to more intuitively reflect whether a cost is incurred in switching from the source satellite to the candidate satellite. For example, the preset normalization algorithm can process the first ratio by taking its logarithm and using the negative of the logarithm as the satellite selection time cost. Through this processing, if the base of the logarithm is an integer and the satellite selection time cost is greater than 0, it indicates that a cost is incurred in switching from the source satellite to the candidate satellite, thus quickly and intuitively obtaining the meaning of the satellite selection time cost. Furthermore, when the satellite switching cost includes multiple aspects, the preset normalization algorithm can transform these multiple aspects to the same scale, allowing for a rapid determination of the satellite switching cost based on these multiple aspects. In other embodiments, the preset normalization algorithm can also be other algorithms, which are not limited in this specification.

[0139] In some embodiments of this specification, the cost of star selection time can be determined by the following formula:

[0140] J T = -log a ( L t A / L t S ) Formula (2)

[0141] in, J T The time cost of star selection can be represented by -log a (·) can represent a preset normalization algorithm. L t A This can represent the second remaining service duration. L t S This can represent the first remaining service duration. The base 'a' in the preset normalization algorithm can be a positive integer greater than 1, such as 2, 5, 10, etc., and this specification does not impose any restrictions on this.

[0142] Specifically, the first remaining service time L t S It can be done through formula L t S =t S end -t S nearset Confirmed, among which t S end This indicates the last moment that SourceStar was able to provide services to user terminals. t S nearset This indicates the moment the source star passes overhead.

[0143] Specifically, the second remaining service time L t A It can be done through formula L t A =t A end -t init Confirmed, among which t A endThis indicates the final moment when the alternative satellite can provide services to the user terminal. t init Indicates the reference switching time.

[0144] refer to Figure 7 As shown, in some embodiments of this specification, the satellite handover cost corresponding to each candidate satellite can be determined in the following ways:

[0145] S601: Determine the shortest distance between the source satellite and the user terminal as the first distance.

[0146] S602: Determine the first position of the candidate satellite and the second position of the user terminal at the target switching time.

[0147] S603: Based on the first position and the second position, determine the second distance between the candidate satellite and the user terminal.

[0148] S604: Based on the first distance and the second distance, determine the satellite selection distance cost corresponding to the candidate satellite, and use the satellite selection distance cost as the satellite switching cost corresponding to the candidate satellite.

[0149] The first distance can be the distance between the source satellite and the user terminal when the source satellite passes overhead. The first position and the second position can be the positions of the candidate satellite and the user terminal in the same coordinate system, so that the second distance between the candidate satellite and the user terminal can be calculated directly in this coordinate system; the first position and the second position can also be the positions of the candidate satellite and the user terminal in different coordinate systems, so that the two positions can be transformed to the same coordinate system, and then the second distance between the candidate satellite and the user terminal can be calculated.

[0150] Among them, the satellite selection distance cost can reflect the communication quality of the satellite, that is, the change of the free space fading loss of the alternative satellite after switching to the alternative satellite compared with the free space fading loss of the source satellite. Based on the satellite selection distance cost, it can be determined whether the free space fading loss increases or decreases after switching from the source satellite to the alternative satellite, and thus determine whether it is necessary to pay a cost to switch from the source satellite to the alternative satellite.

[0151] In some embodiments of this specification, determining the first position of the candidate satellite and the second position of the user terminal at the target switching time may include: obtaining the orbital parameters of the orbital plane where the candidate satellite is located and the second position; determining the second angle of the candidate satellite in the orbital plane at the target switching time based on the orbital parameters; and determining the first position based on the second angle.

[0152] The orbital parameters of the candidate satellite's orbital plane can be determined based on the candidate satellite's ephemeris information. The ephemeris information of the candidate satellite can be determined based on satellite ephemeris information pre-stored in the system, or it can be determined through information interaction with the candidate satellite.

[0153] In some embodiments of this specification, the coordinates of the user terminal in the orbital coordinate system of the candidate satellite at the target handover time can be expressed as ( X ue,A ( t ref ), Y ue,A ( t ref ), Z ue,A ( t ref When ), then the vector representing the distance between the candidate satellite and the user terminal is... AU It can be represented as:

[0154] Formula (3)

[0155] in, R ( t ref This represents the instantaneous orbital radius of the candidate satellite at the target switching time. This represents the first angle of the candidate satellite in its orbital plane at the target switching time. In formula (4) and The coordinates of the candidate satellite on the X-axis and Y-axis in its orbital coordinate system can be represented respectively. Since the candidate satellite moves along its orbital plane, its coordinate on the Z-axis in its orbital coordinate system is 0.

[0156] In some embodiments of this specification, determining the satellite selection distance cost corresponding to the candidate satellite based on the first distance and the second distance may include: determining a second ratio of the first distance to the second distance; determining the communication loss corresponding to the second ratio; and determining the communication loss as the satellite selection distance cost.

[0157] In communication scenarios, the communication loss caused by free space loss can be characterized as a logarithmic function. Therefore, when determining the communication loss corresponding to the second ratio, it can specifically include: taking the logarithm of the second ratio, and processing the logarithmic result based on the gain coefficient of communication quality and distance to obtain the satellite selection distance cost.

[0158] In some embodiments of this specification, the star selection distance cost can be determined by the following formula:

[0159] Formula (4)

[0160] in, J L This can represent the cost of star selection distance. α Gain coefficients can represent communication quality and communication distance. D This can represent the first distance. X 2 AU + Y 2 AU + Z 2 AU It can represent the square of the second distance.

[0161] refer to Figure 8 As shown, in some embodiments of this specification, the satellite handover cost corresponding to each candidate satellite can be determined in the following ways:

[0162] S701: Determine the overpass time of the source satellite, and based on the overpass time and the first service period, determine the first remaining service duration that the source satellite can provide services to the user terminal after its overpass.

[0163] S702: Based on the second service period and the overpass time, determine the second remaining service duration that the alternative satellite can provide services to the user terminal after switching the alternative satellite.

[0164] S703: Based on the first remaining service duration and the second remaining service duration, determine the satellite selection duration cost corresponding to the candidate satellite.

[0165] S704: Determine the shortest distance between the source satellite and the user terminal as the first distance.

[0166] S705: Determine the first position of the candidate satellite and the second position of the user terminal at the target switching time, and determine the second distance between the candidate satellite and the user terminal based on the first position and the second position.

[0167] S706: Based on the first distance and the second distance, determine the satellite selection distance cost corresponding to the candidate satellite.

[0168] S707: Determine the satellite switching cost based on the satellite selection duration cost and the satellite selection distance cost.

[0169] The above Figure 6 , Figure 7 as well as Figure 8The embodiments described herein are three ways to implement satellite switching costs, namely, satellite selection time cost, satellite selection distance cost, and satellite selection time cost and satellite selection distance cost. In other embodiments, satellite switching costs may also include the calculation of other aspects of costs, which are not limited in this specification.

[0170] In some embodiments of this specification, when the satellite handover cost includes costs from at least two aspects, corresponding weighting coefficients can be set for each aspect of the cost. When calculating the satellite handover cost, the costs from each aspect can be normalized and then weighted to obtain the satellite handover cost. The weighting coefficients corresponding to each aspect of the cost can be determined based on the user terminal and / or service scenario in the current communication, determining which aspect of service quality is more important in the current communication. By combining different costs and / or setting different weighting coefficients, the handover satellite selection requirements for different application scenarios can be met, improving the applicability of handover satellite selection.

[0171] In some embodiments of this specification, determining the satellite switching cost based on the satellite selection duration cost and the satellite selection distance cost may include: obtaining a first weighting coefficient corresponding to the satellite selection duration cost and a second weighting coefficient corresponding to the satellite selection distance cost; and performing a weighted summation of the satellite selection duration cost and the satellite selection distance cost based on the first weighting coefficient and the second weighting coefficient to obtain the satellite switching cost.

[0172] When satellite handover costs include both satellite selection duration and satellite selection distance costs, it can be determined whether the current communication prioritizes communication duration or communication quality. Consequently, corresponding weighting coefficients can be set for each of these costs. For example, when a user makes a call using a user terminal, they prioritize call duration and are willing to sacrifice some communication quality; therefore, the first weighting coefficient can be greater than the second weighting coefficient. Conversely, when a user browses video using a user terminal, they prioritize data transfer speed and are willing to sacrifice some browsing time; therefore, the first weighting coefficient can be less than the second weighting coefficient.

[0173] In some embodiments of this specification, determining the target satellite for switching the source satellite among multiple candidate satellites based on the satellite switching cost corresponding to each candidate satellite may include: determining the candidate satellite with the lowest satellite switching cost among multiple candidate satellites as the target satellite.

[0174] In some embodiments of this specification, the calculated satellite handover cost can be used to determine whether a cost is required when switching from the source satellite to each of the candidate satellites. Then, the candidate satellite with the lowest cost that does not require a cost can be selected as the target satellite from among the multiple satellite handover costs. Furthermore, if all satellite handover costs are not less than 0, it indicates that a cost is required regardless of which candidate satellite is switched to; therefore, the source satellite service can be maintained without performing a satellite handover.

[0175] In some embodiments of this specification, determining the target satellite for switching the source satellite from among multiple candidate satellites based on the satellite switching cost corresponding to each candidate satellite may include:

[0176] The candidate satellites are sorted based on the satellite switching cost corresponding to each candidate satellite;

[0177] Based on the ranking results, a target number of satellites are selected as candidate satellites from the multiple alternative satellites.

[0178] Based on preset screening criteria, a target number of candidate satellites are screened, and the candidate satellite with the lowest satellite switching cost is determined as the target satellite from the screening results.

[0179] In the embodiments of this specification, when determining the target satellite, it is also necessary to adjust the satellite selection results by combining preset screening conditions to achieve secondary target satellite selection. Preset screening conditions may include at least one strategy such as elevation angle limitation and communication loss limitation. Taking elevation angle limitation as an example, under this screening condition, there is a certain limitation on the duration for which a satellite can provide communication to the user terminal. The total duration for which the satellite can provide service to the user terminal before and after satellite switching needs to meet the preset duration requirement. Therefore, when selecting the secondary target satellite, it is necessary to also include the switchable alternative satellites corresponding to each alternative satellite of the current source satellite as screening conditions, thereby enabling the determination of the target satellite based on alternative satellites, alternative satellites of alternative satellites, etc.

[0180] Furthermore, due to the limitations of the preset screening conditions in the secondary target satellite selection process, there may be situations where the satellite switching cost of all candidate satellites is greater than 0. In this case, some costs can be sacrificed to select the candidate satellite with the smallest satellite switching cost among those that meet the preset screening conditions and whose satellite switching cost is not less than 0 as the target satellite.

[0181] In a specific scenario example, the satellite handover selection method provided in this specification can be applied to achieve handover between different orbits. In this scenario example, the satellite handover cost is calculated considering service duration and communication fading quality; that is, the satellite handover cost includes the cost of satellite selection duration and the cost of satellite selection distance. Furthermore, this method can be applied to the source satellite-borne base station, which can store the ephemeris information of each satellite in the satellite network. Based on the stored ephemeris information, the position of each satellite at different times, its angle in its orbital plane, and the corresponding initial and final times when it can provide service to the user terminal can be determined. The specific implementation process may include the following:

[0182] S1. Determine whether there is any overlap in the UE service coverage time periods of each candidate satellite.

[0183] The following uses source satellite S and candidate satellite A as an example to illustrate that step S1 may specifically include:

[0184] S11, Let t S nearset This is the moment when Source Star S is closest to UE. t S start , t S end This refers to the start and end times at which the source star can provide services to the UE. t A start , t A end These are the start and end times when alternative satellite A can provide service to the UE. Calculate the duration the source satellite S can still serve the UE after it passes overhead. L t S : L t S =t S end -t S nearset ;

[0185] S12. Confirm whether the source satellite S and satellite A have an intersection period (i.e., the common coverage duration mentioned above) that can simultaneously provide services to the UE.

[0186] S2. If, after the source satellite S passes overhead, there is still a common duration between the alternative satellites A and S that can provide coverage for the UE, then it can be confirmed that satellite A can still provide service to the UE for at least the duration it needs. L t A : L tA =t A end -t init ;

[0187] Among them, if t S nearset > t A start ,but t init = t S nearset ;otherwise t init = t A start .

[0188] If there is no public coverage duration, then L t A If the value is invalid, candidate satellite A will be excluded from the pool of candidate satellites.

[0189] S3, Calculate the cost of star selection time. J T : J T = -log a ( L t A / L t S ).

[0190] S4. If candidate satellite A is not excluded, obtain the latitude argument of candidate satellite A at the reference switching time. UE projection angle in the orbital plane of candidate satellite A and the instantaneous angular velocity of candidate satellite A. u A ( t init ), calculate the specific reference time t ref : .

[0191] S5. Calculate the position of candidate satellite A. t ref Latitude angle Instantaneous orbital radius R ( t ref And the coordinates of the UE in the orbital coordinate system at this moment.X ue,A ( t ref ), Y ue,A ( t ref ), Z ue,A ( t ref Then the vector AU between candidate satellite A and UE is... .

[0192] S6. Calculate the cost of star selection distance. J L : ; α Gain coefficients can represent communication quality and communication distance. D This can represent the shortest distance between the source star S and the UE. X 2 AU + Y 2 AU + Z 2 AU It can be expressed as in t ref Distance between alternative satellite A and UE.

[0193] Satellite switching cost J : J = w 1 ·J L + w 2· J T , w 1 and w 2 represents the weighting coefficients for the cost of star selection distance and the cost of star selection time, respectively.

[0194] S7. Select the candidate satellite with the lowest cost J among multiple candidate satellites as the target satellite; or arrange the priority from smallest to largest cost and perform a secondary target satellite selection based on preset screening conditions.

[0195] Since the essence of satellite handover cost is the cost incurred relative to the source satellite S after switching to another satellite, if there is no alternative satellite with a cost function J less than 0, no handover will be performed, and the source satellite will continue to serve the UE; otherwise, the alternative satellite with the smallest cost function J will be selected as the target satellite.

[0196] This specification describes an embodiment that, from the perspective of the source satellite, before it provides service to the user terminal or is determined to be unable to continue providing service, automatically collects multiple surrounding satellites that can provide service to the user and share common coverage time with the source satellite as candidate satellites. Simultaneously, it considers the remaining service time of the candidate satellites and the impact of free-space fading loss on service quality, selecting the candidate satellite with the lowest switching cost as the target satellite, or screening satellites capable of providing service and prioritizing them for subsequent secondary selection of target satellites. This approach is applicable to various switching scenarios; furthermore, the data processing is simple, requires minimal input information, and has low computational power requirements, enabling fast and efficient switching satellite selection.

[0197] Based on the above-described satellite selection method, this specification also provides a satellite selection device. It is understood that the satellite selection device provided in this specification can be applied to the user equipment side. The user equipment can calculate the satellite handover cost from the source satellite to each candidate satellite based on the satellite selection device, and determine the target satellite corresponding to the source satellite among the multiple candidate satellites based on the satellite handover cost. The satellite selection device provided in this specification can also be applied to the satellite side (e.g., the source satellite's onboard base station), or the server side of a satellite communication service platform. Accordingly, the satellite or server can calculate the satellite handover cost from the source satellite to each candidate satellite based on the satellite selection device, and determine the target satellite corresponding to the source satellite among the multiple candidate satellites based on the satellite handover cost. Figure 9 The diagram shown is a schematic representation of the satellite selection switching device provided in an embodiment of this specification. Figure 9 As shown, the satellite selection switching device may include:

[0198] The acquisition module 801 is used to acquire the first service period during which the source satellite can provide services to the user terminal and the second service period during which multiple alternative satellites can provide services to the user terminal.

[0199] The determining module 802 is used to determine the reference switching time corresponding to the multiple candidate satellites based on the first service period and multiple second service periods, and to determine the target switching time corresponding to each candidate satellite based on the reference switching time and the orbital data of each candidate satellite.

[0200] Selection module 803 is used to determine the satellite handover cost from the source satellite to each candidate satellite based on the target handover time and at least one indicator related to measuring satellite service quality, and to determine the target satellite corresponding to the source satellite from among multiple candidate satellites based on the satellite handover cost corresponding to each candidate satellite.

[0201] The satellite switching cost is used to characterize the cost incurred when a user terminal switches from the source satellite to each of the alternative satellites.

[0202] In some embodiments of this specification, the candidate satellite is a satellite that shares a common coverage period with the source satellite. The determining module 802 can specifically be used to: determine the overpass time of the source satellite; determine the reference handover time corresponding to the candidate satellite based on the second service period and the overpass time; determine the angle difference between the user terminal and the candidate satellite's orbital plane at the reference handover time; determine the angular velocity of the candidate satellite at the reference handover time; and determine the target handover time corresponding to the candidate satellite based on the angular velocity, the angle difference, and the reference handover time.

[0203] In some embodiments of this specification, the angle difference may include at least one of the following: latitude argument angle difference, true near angle angle difference, deviated near angle angle difference, mean near angle angle difference, and perigee argument angle difference.

[0204] In some embodiments of this specification, when determining the reference handover time corresponding to the candidate satellite based on the second service period and the overpass time, the determining module 802 may specifically be used to: determine the initial time when the candidate satellite can provide services to the user terminal based on the second service period; when the initial time is less than the overpass time, the reference handover time is the overpass time; otherwise, the reference handover time is the initial time.

[0205] In some embodiments of this specification, when determining the target switching time corresponding to the candidate satellite based on the angular velocity, the angle difference, and the reference switching time, the determining module 802 may specifically be used to: determine the first duration for the candidate satellite to move from the reference position corresponding to the reference switching time to the overpass position based on the angle difference and the angular velocity; and determine the target switching time based on the first duration and the reference switching time.

[0206] In some embodiments of this specification, the target switching time can be determined by the following formula:

[0207] ;

[0208] in, t ref This can represent the target switching time. t init This can represent the reference switching time. This can represent the first angle of the candidate satellite in its orbital plane at the reference switching time. This can represent the second angle of the user terminal in the orbital plane of the alternative satellite at the reference switching time. u A( t init ) can represent the angular velocity of the candidate satellite at the reference switching time.

[0209] In some embodiments of this specification, the selection module 803 may be used to: determine the overpass time of the source satellite, and determine a first remaining service duration that the source satellite can provide services to the user terminal after the overpass based on the overpass time and the first service period; determine a reference handover time corresponding to the candidate satellite based on the second service period and the overpass time; determine a second remaining service duration that the candidate satellite can provide services to the user terminal after handing over the candidate satellite based on the second service period and the reference handover time; determine the satellite selection duration cost corresponding to the candidate satellite based on the first remaining service duration and the second remaining service duration, and use the satellite selection duration cost as the satellite handover cost corresponding to the candidate satellite.

[0210] In some embodiments of this specification, when the selection module 803 determines the satellite selection time cost corresponding to the candidate satellite based on the first remaining service time and the second remaining service time, it may specifically be used to: determine a first ratio of the second remaining service time to the first remaining service time, and process the first ratio based on a preset normalization algorithm to obtain the satellite selection time cost.

[0211] In some embodiments of this specification, the cost of star selection time can be determined by the following formula:

[0212] J T = -log a ( L t A / L t S );

[0213] in, J T The time cost of star selection is represented by -log a (·) indicates a preset normalization algorithm. L t A This indicates the second remaining service duration. L t S This indicates the first remaining service duration.

[0214] In some embodiments of this specification, the selection module 803 may be used to: determine the shortest distance between the source satellite and the user terminal as a first distance; determine the first position of the candidate satellite and the second position of the user terminal at the target switching time; determine the second distance between the candidate satellite and the user terminal based on the first position and the second position; determine the satellite selection distance cost corresponding to the candidate satellite based on the first distance and the second distance, and use the satellite selection distance cost as the satellite switching cost corresponding to the candidate satellite.

[0215] In some embodiments of this specification, when determining the first position of the candidate satellite and the second position of the user terminal at the target switching time, the selection module 803 may be used to: obtain the orbital parameters of the orbital plane where the candidate satellite is located and the second position; determine the second angle of the candidate satellite in the orbital plane at the target switching time based on the orbital parameters; and determine the first position based on the second angle.

[0216] In some embodiments of this specification, when the selection module 803 determines the satellite selection distance cost corresponding to the candidate satellite based on the first distance and the second distance, it may specifically be used to: determine a second ratio of the first distance to the second distance; determine the communication loss corresponding to the second ratio; and determine the communication loss as the satellite selection distance cost.

[0217] In some embodiments of this specification, the star selection distance cost can be determined by the following formula:

[0218] ;

[0219] in, J L Indicates the cost of star selection distance. α Gain coefficient representing communication quality and communication distance. D Indicates the first distance. X 2 AU + Y 2 AU + Z 2 AU This represents the square of the second distance.

[0220] In some embodiments of this specification, the selection module 803 may specifically be used to: determine the overpass time of the source satellite, and determine a first remaining service duration that the source satellite can provide services to the user terminal after the overpass based on the overpass time and the first service period; determine a second remaining service duration that the alternative satellite can provide services to the user terminal after switching the alternative satellite based on the second service period and the overpass time; determine the satellite selection time cost corresponding to the alternative satellite based on the first remaining service duration and the second remaining service duration; determine the shortest distance between the source satellite and the user terminal as a first distance; determine the first position of the alternative satellite and the second position of the user terminal at the target switching time, and determine a second distance between the alternative satellite and the user terminal based on the first position and the second position; determine the satellite selection distance cost corresponding to the alternative satellite based on the first distance and the second distance; and determine the satellite switching cost based on the satellite selection time cost and the satellite selection distance cost.

[0221] In some embodiments of this specification, when the selection module 803 determines the satellite switching cost based on the satellite selection duration cost and the satellite selection distance cost, it may be used to: obtain a first weighting coefficient corresponding to the satellite selection duration cost and a second weighting coefficient corresponding to the satellite selection distance cost; and, based on the first weighting coefficient and the second weighting coefficient, perform a weighted summation of the satellite selection duration cost and the satellite selection distance cost to obtain the satellite switching cost.

[0222] In some embodiments of this specification, the selection module 803 determines the target satellite for switching the source satellite among multiple candidate satellites based on the satellite switching cost corresponding to each candidate satellite. Specifically, it can be used to: determine the candidate satellite with the lowest satellite switching cost among multiple candidate satellites as the target satellite.

[0223] In some embodiments of this specification, when the selection module 803 determines the target satellite for switching the source satellite from multiple candidate satellites based on the satellite switching cost corresponding to each candidate satellite, it may specifically be used to: sort multiple candidate satellites based on the satellite switching cost corresponding to each candidate satellite; select a target number of satellites as candidate satellites from the multiple candidate satellites based on the sorting result; filter the target number of candidate satellites based on preset filtering conditions, and determine the candidate satellite with the lowest satellite switching cost as the target satellite from the filtering result.

[0224] In some embodiments of this specification, the above-described apparatus is applied to a source star-borne base station.

[0225] The descriptions and functions of the above modules can be found in the section on switching star selection methods, and will not be repeated here.

[0226] One embodiment of the present invention also provides an electronic device, such as... Figure 10 As shown, located on a satellite, electronic device 901 may include one or more processors 902, such as one or more central processing units (CPUs), each of which may implement one or more hardware threads. Electronic device 901 may also include any memory 903 for storing information of any kind, such as code, settings, data, etc. Non-limitingly, for example, memory 903 may include any type of RAM, any type of ROM, flash memory, hard disk, optical disk, etc. More generally, any memory can use any technology to store information. Furthermore, any memory may provide volatile or non-volatile retention of information. Furthermore, any memory may represent a fixed or removable component of electronic device 901. In one case, when processor 902 executes associated instructions stored in any memory or combination of memories, electronic device 901 may perform any operation of the associated instructions. Electronic device 901 also includes one or more drive mechanisms 904 for interacting with any memory, such as hard disk drive mechanisms, optical disk drive mechanisms, etc.

[0227] Electronic device 901 may also include one or more network interfaces 905 for exchanging data with other devices via one or more communication links 906. One or more communication buses 907 couple the components described above together.

[0228] Communication link 906 can be implemented in any way, such as via a local area network (LAN), a wide area network (WAN) (e.g., the Internet), a point-to-point connection, or any combination thereof. Communication link 906 may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc., governed by any protocol or combination of protocols.

[0229] This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, performs the steps of the above-described method.

[0230] This invention also provides a computer-readable instruction, wherein when a processor executes the instruction, the program therein causes the processor to perform the method described in any of the foregoing embodiments.

[0231] It should be understood that, in various embodiments of the present invention, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0232] It should also be understood that, in the embodiments of the present invention, the term "and / or" is merely a description of the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the present invention, the character " / " generally indicates that the preceding and following associated objects have an "or" relationship.

[0233] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this invention can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of each example have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0234] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0235] In the embodiments provided by this invention, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, or may be electrical, mechanical, or other forms of connection.

[0236] The units described as separate components may or may not be physically separate. The 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 the units can be selected to achieve the purpose of the embodiments of the present invention, depending on actual needs.

[0237] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0238] 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, in essence, or the part 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 to cause an electronic device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0239] Specific embodiments have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A method for switching star selection, characterized in that, include: The first service period during which the source satellite can provide services to the user terminal and the second service period during which multiple alternative satellites can provide services to the user terminal are obtained. Based on the first service period and multiple second service periods, a reference switching time corresponding to multiple candidate satellites is determined, and based on the reference switching time and the orbital data of each candidate satellite, a target switching time corresponding to each candidate satellite is determined. Determine the overpass time of the source satellite, and based on the overpass time and the first service period, determine the first remaining service duration that the source satellite can provide services to the user terminal after its overpass. Based on the multiple second service periods and the overpass time, determine the reference handover time for each candidate satellite; Based on the multiple second service periods and the reference switching time corresponding to each candidate satellite, determine the second remaining service duration that each candidate satellite can provide services to the user terminal after switching each candidate satellite; Based on the first remaining service time and the second remaining service time corresponding to each candidate satellite, the satellite selection time cost corresponding to each candidate satellite is determined, the satellite selection time cost corresponding to each candidate satellite is used as the satellite switching cost corresponding to each candidate satellite, and the target satellite corresponding to the source satellite is determined from multiple candidate satellites based on the satellite switching cost corresponding to each candidate satellite. The satellite switching cost is used to characterize the cost incurred when a user terminal switches from the source satellite to each of the alternative satellites.

2. The switching star selection method according to claim 1, characterized in that, The candidate satellites are those that share a common coverage period with the source satellite. The target switching time for each candidate satellite is determined in the following way: Determine the overpass time of the source star; Based on the second service period and the overhead time, the reference handover time corresponding to the candidate satellite is determined; The user terminal determines the angle difference between the orbital plane of the candidate satellite and the candidate satellite at the reference handover time. The angular velocity of the candidate satellite at the reference switching time is determined, and the target switching time corresponding to the candidate satellite is determined based on the angular velocity, the angle difference, and the reference switching time.

3. The switching star selection method according to claim 2, characterized in that, The angle difference includes at least one of the following: the angle difference of latitude argument, the angle difference of true near angle, the angle difference of deviated near angle, the angle difference of level near angle, and the angle difference of perigee argument.

4. The switching star selection method according to claim 2, characterized in that, Based on the second service period and the overhead time, the reference handover time corresponding to the candidate satellite is determined, including: Based on the second service period, determine the initial time when the candidate satellite can provide services to the user terminal; When the initial time is less than the overpass time, the reference switching time is the overpass time; otherwise, the reference switching time is the initial time.

5. The switching star selection method according to claim 2, characterized in that, Based on the angular velocity, the angle difference, and the reference switching time, the target switching time corresponding to the candidate satellite is determined, including: Based on the angle difference and the angular velocity, determine the first time interval for the candidate satellite to move from the reference position corresponding to the reference switching time to the overpass position; The target switching time is determined based on the first duration and the reference switching time.

6. The switching star selection method according to claim 2 or 5, characterized in that, The target switching time is determined by the following formula: ； in, t ref Indicates the target switching time. t init Indicates the reference switching time, This represents the first angle of the candidate satellite in its orbital plane at the reference switching time. This represents the second angle of the user terminal in the orbital plane of the alternative satellite at the reference handover time. u A ( t init ) represents the angular velocity of the candidate satellite at the reference switching time.

7. The switching star selection method according to claim 1, characterized in that, Based on the first remaining service duration and the second remaining service duration, the satellite selection time cost corresponding to the candidate satellite is determined, including: A first ratio of the second remaining service duration to the first remaining service duration is determined, and the first ratio is processed based on a preset normalization algorithm to obtain the star selection duration cost.

8. The switching star selection method according to claim 1 or 7, characterized in that, The time cost for star selection is determined by the following formula: J T = -log a ( L t A / L t S ); in, J T The time cost of star selection is represented by -log a (·) indicates a preset normalization algorithm. L t A This indicates the second remaining service duration. L t S This indicates the first remaining service duration.

9. The switching star selection method according to claim 1, characterized in that, The satellite handover cost for each candidate satellite is determined in the following way: Determine the overpass time of the source satellite, and based on the overpass time and the first service period, determine the first remaining service duration that the source satellite can provide services to the user terminal after its overpass. Based on the second service period and the overhead time, determine the second remaining service duration that the alternative satellite can provide services to the user terminal after switching the alternative satellite; Based on the first remaining service time and the second remaining service time, the satellite selection time cost corresponding to the candidate satellite is determined; The shortest distance between the source satellite and the user terminal is determined as the first distance; Determine the first position of the candidate satellite and the second position of the user terminal at the target switching time, and determine the second distance between the candidate satellite and the user terminal based on the first position and the second position; Based on the first distance and the second distance, determine the satellite selection distance cost corresponding to the candidate satellite; The satellite switching cost is determined based on the satellite selection time cost and the satellite selection distance cost.

10. The switching star selection method according to claim 9, characterized in that, Determining the first position of the candidate satellite and the second position of the user terminal at the target handover time includes: Obtain the orbital parameters of the orbital plane where the candidate satellite is located and the second position; Based on the orbital parameters, determine the second angle of the candidate satellite in its orbital plane at the target switching time; The first position is determined based on the second angle.

11. The switching star selection method according to claim 9, characterized in that, Based on the first distance and the second distance, the satellite selection distance cost corresponding to the candidate satellite is determined, including: Determine a second ratio between the first distance and the second distance; Determine the communication loss corresponding to the second ratio, and determine the communication loss as the cost of the satellite selection distance.

12. The switching star selection method according to claim 9, characterized in that, The cost of star selection distance is determined by the following formula: ； in, J L Indicates the cost of star selection distance. α Gain coefficient representing communication quality and communication distance. D Indicates the first distance. X 2 AU + Y 2 AU + Z 2 AU This represents the square of the second distance.

13. The switching star selection method according to claim 9, characterized in that, Based on the satellite selection duration cost and the satellite selection distance cost, the satellite switching cost is determined, including: Obtain the first weight coefficient corresponding to the star selection time cost and the second weight coefficient corresponding to the star selection distance cost; Based on the first weighting coefficient and the second weighting coefficient, the satellite selection duration cost and the satellite selection distance cost are weighted and summed to obtain the satellite switching cost.

14. The switching star selection method according to claim 1, characterized in that, Based on the satellite handover cost corresponding to each candidate satellite, the target satellite for handover corresponding to the source satellite is determined from multiple candidate satellites, including: The candidate satellite with the lowest satellite switching cost among multiple candidate satellites is determined as the target satellite.

15. The switching star selection method according to claim 1, characterized in that, Based on the satellite handover cost corresponding to each candidate satellite, the target satellite for handover corresponding to the source satellite is determined from multiple candidate satellites, including: The candidate satellites are sorted based on the satellite switching cost corresponding to each candidate satellite; Based on the ranking results, a target number of satellites are selected as candidate satellites from the multiple alternative satellites. Based on preset screening criteria, a target number of candidate satellites are screened, and the candidate satellite with the lowest satellite switching cost is determined as the target satellite from the screening results.

16. The switching star selection method according to claim 1, characterized in that, It is applied to the source star-borne base station.

17. A satellite selection switching device, characterized in that, include: The acquisition module is used to acquire the first service period during which the source satellite can provide services to the user terminal and the second service period during which multiple alternative satellites can provide services to the user terminal. The determination module is used to determine the reference switching time corresponding to multiple candidate satellites based on the first service period and multiple second service periods, and to determine the target switching time corresponding to each candidate satellite based on the reference switching time and the orbital data of each candidate satellite. The selection module is used to determine the overpass time of the source satellite, and based on the overpass time and the first service period, determine the first remaining service duration that the source satellite can provide services to the user terminal after its overpass. Based on the multiple second service periods and the overpass time, determine the reference handover time for each candidate satellite; Based on the multiple second service periods and the reference switching time corresponding to each candidate satellite, determine the second remaining service duration that each candidate satellite can provide services to the user terminal after switching each candidate satellite; Based on the first remaining service time and the second remaining service time corresponding to each candidate satellite, the satellite selection time cost corresponding to each candidate satellite is determined, the satellite selection time cost corresponding to each candidate satellite is used as the satellite switching cost corresponding to each candidate satellite, and the target satellite corresponding to the source satellite is determined from multiple candidate satellites based on the satellite switching cost corresponding to each candidate satellite. The satellite switching cost is used to characterize the cost incurred when a user terminal switches from the source satellite to each of the alternative satellites.

18. An electronic device, characterized in that, It includes a processor and a memory for storing processor-executable instructions, wherein the processor, when executing the instructions, implements the steps of the method according to any one of claims 1 to 16.

19. A computer storage medium, characterized in that, The computer storage medium stores computer program instructions, which, when executed by a processor, implement the steps of the method according to any one of claims 1 to 16.

20. A computer program product, characterized in that, It includes a computer program that, when executed by a processor, implements the steps of the method according to any one of claims 1 to 16.

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