A dynamic elevation angle weighted based NTN conditional handover method

Abstract

The application discloses a NTN condition switching method based on dynamic elevation angle weighting, and belongs to the technical field of wireless communication, which comprises the following steps: obtaining D1 / T1 event configuration information, satellite ephemeris of a service satellite and a target satellite from an NR network; obtaining a user equipment position and calculating satellite elevation angles of the service satellite and the target satellite in combination with the satellite ephemeris; obtaining satellite signal quality RSRP of the service satellite and the target satellite and performing dynamic weighting based on the satellite elevation angles, satellite types and path loss; performing A3 event verification according to the user equipment position, the dynamic weighting result and the D1 / T1 event configuration information, and if the A3 event is met, a process of switching to the target satellite is initiated. The application optimizes the switching decision by combining the dynamic elevation angle weighting with the satellite type and the path loss characteristics on the basis of the D1 / T1 event, solves the limitations of the pure position / time triggering, and improves the switching effect.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to an NTN conditional handover method based on dynamic elevation angle weighting. Background Technology

[0002] In non-terrestrial network (NTN) scenarios, handover specifically refers to the process of a user equipment (UE) switching from its currently accessed satellite beam or satellite node to another satellite beam or satellite node. Its core objective is to ensure communication continuity when the satellite coverage area changes dynamically.

[0003] Because satellites orbit at high altitudes, their signals are incident on the ground almost perpendicularly, resulting in minimal signal strength differences between the center and edges of NTN cells, and eliminating significant "near-far effect." Therefore, traditional signal strength-based handover strategies used in terrestrial networks are difficult to apply directly to NTN scenarios. To overcome this limitation, NTN introduces location-based and time-based handover mechanisms, corresponding to the definitions of D1 and T1 events, respectively.

[0004] The existing NTN conditional switching (CHO) technology (based on D1 events, T1 events, and traditional signal strength triggering mechanisms) has the following problems in practical applications:

[0005] 1. Traditional signal strength triggering mechanisms (A events) are difficult to adapt to the characteristics of NTN signals.

[0006] In terrestrial networks, events such as A3 / A5 trigger handover based on differences in signal strength. However, in NTN, the signal strength variation within a beam is minimal, and the path loss difference between different satellites is much smaller than that of terrestrial base stations. If a fixed threshold is used, handover will be delayed (the UE may have entered the target beam but handover will not be triggered); if the threshold is lowered, handover may be mistakenly triggered due to signal fading, making it impossible to balance accuracy and timeliness.

[0007] 2. D1 event (location triggered) ignores differences in satellite signal quality.

[0008] The D1 event determines the handover requirement based on the distance between the UE and the cell center, but "close distance" does not equal "good signal": satellite signal quality is strongly correlated with elevation angle (high elevation angle signal propagation is stable and has less loss, while low elevation angle signal is easily blocked and attenuated), while the D1 event only relies on distance (2km accuracy), which may mistakenly select satellites that are "close but have low elevation angle (poor signal)" as the target cell, resulting in a decrease in service quality after handover.

[0009] 3. The time window of the T1 event (time-triggered) is not well adapted to the signal evaluation mechanism.

[0010] The T1 event controls the timing of measurements through a UTC time window, but it has two drawbacks: First, the window duration is fixed and cannot be adapted to the motion characteristics of different satellites (e.g., LEO satellites change elevation angles rapidly, and a fixed long window will cause drastic changes in signal quality within the window, leading to decision failure); second, the A event is evaluated based on the original RSRP within the window, which is susceptible to transient fading interference, resulting in false signal advantages (e.g., a brief increase in RSRP for low-elevation satellites), leading to invalid handovers.

[0011] 4. The issues of target cell selection and signaling storm have not been effectively resolved.

[0012] Existing technologies do not clearly define the collaborative selection criteria for "signal quality" and "service duration," which may prioritize cells with long service durations but poor signal (such as high-orbit satellites), leading to frequent handovers. At the same time, satellite beams have a large coverage area and move quickly, making it easy for a large number of UEs to trigger handovers at the same time. Existing mechanisms lack effective means for distributed access, which can easily cause signaling storms and resource congestion. Summary of the Invention

[0013] The purpose of this invention is to overcome the shortcomings of the prior art and provide an NTN conditional handover method based on dynamic elevation angle weighting. Based on the D1 / T1 event, it proposes to optimize the handover decision by combining dynamic elevation angle weighting with satellite type and path loss characteristics, thereby solving the limitations of simple position / time triggering and overcoming the technical problems of existing NTN conditional handover (CHO) technology.

[0014] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0015] This invention provides a dynamic elevation angle-weighted NTN conditional handover method, comprising:

[0016] Obtain D1 / T1 event configuration information, serving satellites, and target satellites' ephemeris from the NR network;

[0017] Obtain the user equipment's own location and calculate the satellite elevation angles of the serving satellite and the target satellite by combining the satellite ephemeris;

[0018] The signal quality RSRP of the serving satellite and the target satellite is obtained and dynamically weighted based on the satellite elevation angle, satellite type, and path loss;

[0019] Based on the user equipment's own location, the dynamic weighting result, and the D1 / T1 event configuration information, A3 event verification is performed. If the A3 event is satisfied, the process of switching to the target satellite is initiated.

[0020] Optionally, the satellite elevation angle for:

[0021]

[0022] In the formula, The orbital altitude of the satellite. The altitude of the user equipment. This refers to the horizontal distance between the user equipment and the satellite's nadir point.

[0023] Optionally, the dynamic weighting value of the satellite signal quality RSRP for:

[0024]

[0025] In the formula, The satellite elevation angle. For orbital coefficients, This is the loss factor.

[0026] Optionally, if the satellite is an LEO satellite, then the orbital coefficient... The value range is from 0.8 to 1.0;

[0027] If the satellite is a MEO satellite, then the orbital coefficient The value range is from 0.6 to 0.8;

[0028] If the satellite is a GEO satellite, then the orbital coefficient The value range is from 0.4 to 0.6.

[0029] Optional, if Then the loss factor The value range is from 0.8 to 1.0;

[0030] like Then the loss factor The value range is from 0.6 to 0.8;

[0031] like Then the loss factor The value is 0.5.

[0032] Optionally, the D1 event configuration information includes a first threshold value. Second threshold value Weighted threshold and duration threshold ;

[0033] A3 event verification based on the user equipment's own location, dynamic weighting results, and D1 event configuration information includes:

[0034] The user equipment determines whether the D1 event is triggered based on its own location, dynamic weighting result, and D1 event configuration information. If the D1 event is triggered, the user equipment reports the D1 event to the NR network.

[0035] The NR network verifies the legitimacy of the D1 event trigger. If the verification is successful, it configures the A3 event configuration information based on the dynamic weighted value of the satellite signal quality RSRP and sends it to the user equipment.

[0036] User equipment performs A3 event verification based on the dynamic weighted value of the satellite signal quality RSRP:

[0037] like And duration If so, then event A3 verification passes;

[0038] In the formula, These are the dynamic weighted values ​​of the satellite signal quality RSRP for the target satellite and the service satellite, respectively. This is the duration threshold for event A3.

[0039] If the serving satellite is a LEO satellite, then If the serving satellite is a MEO satellite or a GEO satellite, then , .

[0040] Optionally, determining whether the D1 event has been triggered includes:

[0041] like and If so, then the distance condition is satisfied;

[0042] like If so, then the weighting condition is met;

[0043] like If the condition is met, the D1 event is triggered.

[0044] In the formula, These are the spherical distances between the beam centers of the user equipment and the service satellite and the target satellite, respectively. This is the duration during which both the distance condition and the weighting condition are satisfied.

[0045] Optionally, the T1 event configuration information includes the window start time, window duration, and weighted threshold value. Duration threshold of A3 event ;

[0046] A3 event verification based on the dynamic weighting result and T1 event configuration information includes:

[0047] Upon reaching the start time of the window, the user equipment performs A3 event verification based on the dynamically weighted value of the satellite signal quality RSRP:

[0048] During the window duration, if And duration If so, then event A3 verification passes;

[0049] Among them, if ,but , ,but , , The first elevation angle threshold, The satellite elevation angle for user equipment and service satellites.

[0050] Optionally, the process of switching to the target satellite includes:

[0051] Obtain a set of candidate satellites and filter out satellite elevation angles. Candidate satellites, The second elevation angle threshold;

[0052] Calculate the combined score of the remaining candidate satellites in the candidate satellite set. :

[0053]

[0054] In the formula, The 1st among the remaining candidate satellites The overall score of each candidate satellite Weighting coefficients for service quality and service duration; The 1st among the remaining candidate satellites The dynamic weighted value of the satellite signal quality RSRP of each candidate satellite and the remaining time available to serve user equipment; The maximum value of the satellite signal quality RSRP and service duration for the candidate satellites;

[0055] Select Overall Score highest and The candidate satellites were selected as the target satellites. This is the third weighted threshold value;

[0056] During the window duration, the user device switching time Allocation by elevation angle interval:

[0057]

[0058] In the formula, The window start time and window duration; The elevation angle between the user equipment and the target satellite.

[0059] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0060] This invention provides a dynamic elevation angle-weighted NTN conditional handover method. It dynamically weights the signal quality response ratio (RSRP) of the serving and target satellites based on satellite elevation angle, satellite type, and path loss, achieving differentiated adaptation for satellites in different orbits. A dual-event triggering mechanism is employed: Event D1 fuses the distance and weighted RSRP difference condition, while Event T1 dynamically adjusts the window based on the elevation angle change rate and uses a weighted A3 event for evaluation, overcoming the limitations of simple position / time triggering. Simultaneously, when selecting target satellites, priority is given to satellites with acceptable weighted RSRP and long service durations, forcibly excluding low-quality candidates with excessively small elevation angles. This allows for the selection of more suitable handover satellites, improving service stability. The elevation angle is calculated in real-time using GNSS position and satellite ephemeris, and the network side completes the handover decision based on the weighted value, reducing signaling interaction. Attached Figure Description

[0061] Figure 1 This is a flowchart of the NTN conditional switching method based on dynamic elevation angle weighting provided in an embodiment of the present invention;

[0062] Figure 2 This is a timing diagram of the dynamic elevation angle-weighted NTN condition switching method corresponding to the D1 event provided in this embodiment of the invention;

[0063] Figure 3 This is a timing diagram of the NTN condition switching method with dynamic elevation angle weighting corresponding to the T1 event provided in this embodiment of the invention. Detailed Implementation

[0064] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0065] The D1 event is defined as follows: it is triggered when the distance between the UE and the reference location of the serving cell exceeds threshold 1, and the distance between the UE and the reference location of the neighboring cell is less than threshold 2. Similar to the A5 event, the D1 event measures distance, and its reference location is represented by an elliptical point model (containing longitude and latitude information) at the center of the cell.

[0066] The T1 event is defined as follows: The UE performs a measurement within a time window after Coordinated Universal Time (UTC) and before UTC+duration. UTC is based on the atomic second definition and has an error of no more than 0.9 milliseconds compared to UTC; duration is the duration of the measurement window, which is an integer from 1 to 6000 (in units of 100 milliseconds), meaning the maximum duration is 600 seconds.

[0067] To reduce UE power consumption and improve user experience, the T1 event is typically configured in conjunction with A3, A4, or A5 events (hereinafter collectively referred to as A events): The UE receives UTC, duration, and A event parameters as trigger conditions, and starts measurement only after UTC; if the A event is satisfied, the UE reports the event to the network, and the network subsequently issues candidate cell configuration information, which the UE uses to complete the handover to the target cell. Before UTC, even if the A event is satisfied, the measurement and handover process will not be triggered; after UTC+duration, if the UE fails to access the target cell, the UE and the network will discard the handover configuration for that target cell to avoid occupying target cell resources for an extended period. Similarly, the D1 event is also configured in conjunction with the A event; the UE only begins to evaluate the A event after the D1 event is satisfied.

[0068] The elevation angle of a satellite is the angle between the horizon (horizontal plane) at the observer's location and the line of sight to the satellite. Simply put, it represents the satellite's altitude in the sky: 0° when the satellite is just rising; and 90° (called the "zenith") when the satellite is directly above the observer. This angle is used to describe the satellite's position relative to a ground observer.

[0069] Example 1:

[0070] like Figure 1 As shown, this invention provides a dynamic elevation angle-weighted NTN conditional handover method, comprising the following steps:

[0071] Step S1: Obtain D1 / T1 event configuration information, service satellite and target satellite ephemeris from the NR network;

[0072] Step S2: Obtain the user equipment's own location and calculate the satellite elevation angles of the serving satellite and the target satellite by combining the satellite ephemeris.

[0073] Step S3: Obtain the satellite signal quality RSRP of the serving satellite and the target satellite and dynamically weight it based on satellite elevation angle, satellite type, and path loss;

[0074] Step S4: Verify the A3 event based on the user equipment's own location, dynamic weighting results, and D1 / T1 event configuration information. If the A3 event is satisfied, initiate the process of switching to the target satellite.

[0075] This invention employs a dual-event triggering mechanism: the D1 event fuses the distance and weighted RSRP difference condition, while the T1 event dynamically adjusts the window based on the elevation angle change rate and is evaluated using the weighted A3 event. For ease of understanding, the switching methods for the D1 and T1 events will be explained separately below.

[0076] like Figure 2 The figure shows the timing diagram of the NTN conditional switching method with dynamic elevation angle weighting corresponding to event D1.

[0077] Step S2.1: Initialization and parameter configuration.

[0078] The user equipment obtains D1 event configuration information from the NR network. The D1 event configuration information includes: a first threshold value. Second threshold value Weighted threshold and duration threshold .

[0079] The NR network requests the satellite ephemeris of the service / target satellite from the satellite ephemeris server and distributes it to the user equipment.

[0080] Step S2.2, Elevation angle calculation and weighted evaluation.

[0081] User equipment obtains its own position via GNSS and calculates the satellite elevation angles of the serving satellite and the target satellite by combining the satellite ephemeris data. :

[0082]

[0083] In the formula, The orbital altitude of the satellite. The altitude of the user equipment. This refers to the horizontal distance between the user equipment and the satellite's nadir point.

[0084] User equipment acquires the satellite signal quality RSRP of the serving satellite and the target satellite and dynamically weights it based on satellite elevation angle, satellite type, and path loss. The dynamic weighted value of the satellite signal quality RSRP is... for:

[0085]

[0086] In the formula, The satellite elevation angle. For orbital coefficients, This is the loss factor.

[0087] Orbit coefficient Selected by satellite type:

[0088] Optionally, if the satellite is an LEO satellite, then the orbital coefficient... The value range is from 0.8 to 1.0;

[0089] If the satellite is a MEO satellite, then the orbital coefficient The value range is from 0.6 to 0.8;

[0090] If the satellite is a GEO satellite, then the orbital coefficient The value range is from 0.4 to 0.6.

[0091] Loss factor Selected by the elevation angle related to path loss:

[0092] like Then the loss factor The value range is from 0.8 to 1.0;

[0093] like Then the loss factor The value range is from 0.6 to 0.8;

[0094] like Then the loss factor The value is 0.5.

[0095] Step S2.3, D event trigger judgment.

[0096] Determine whether the D1 event is triggered based on the user device's own location, dynamic weighting results, and D1 event configuration information:

[0097] like and If so, then the distance condition is satisfied;

[0098] like If so, then the weighting condition is met;

[0099] like If the condition is met, the D1 event is triggered.

[0100] In the formula, These are the spherical distances between the beam centers of the user equipment and the service satellite and the target satellite, respectively. This is the duration during which both the distance condition and the weighting condition are satisfied, and it is usually set to 100ms.

[0101] Step S2.4, A3 event verification and judgment.

[0102] If a D1 event is triggered, the user equipment will report the D1 event trigger to the NR network;

[0103] The NR network verifies the legitimacy of the D1 event trigger. If the verification is successful, it configures the A3 event configuration information based on the dynamic weighted value of the satellite signal quality RSRP and sends it to the user equipment.

[0104] User equipment performs A3 event verification based on the dynamic weighted value of the satellite signal quality RSRP:

[0105] like And duration If so, then event A3 verification passes;

[0106] In the formula, These are the dynamic weighted values ​​of the satellite signal quality RSRP for the target satellite and the service satellite, respectively. This is the duration threshold for the A3 event, typically set to 200ms.

[0107] If the serving satellite is a LEO satellite, then If the serving satellite is a MEO satellite or a GEO satellite, then , .

[0108] Because the signal changes rapidly and requires a low threshold, it is usually... Set to 3dB. A high threshold is needed for signal stability to avoid frequent switching; this is typically the case. Set to 5dB.

[0109] like Figure 3 The figure shows the timing diagram of the NTN conditional switching method with dynamic elevation angle weighting corresponding to event T1.

[0110] Step S3.1, T1 event configuration phase.

[0111] The NR network acquires the elevation angle change rate of the serving satellites and calculates the window duration, which is then sent to the user equipment as T1 event configuration information. The T1 event configuration information also includes the window start time and weighted threshold value. Duration threshold of A3 event .

[0112]

[0113] In the formula, The value is a constant, such as 5°, to ensure that the elevation angle change within the window does not exceed 5°, thus avoiding drastic changes in signal quality. The elevation angle calculation for the satellite's elevation angle change rate has already been provided above and will not be repeated here; Constraints: , For the corresponding threshold value.

[0114] Step S3.2, Measurement and evaluation within the time window.

[0115] Upon reaching the start time of the window, the user equipment performs A3 event verification based on the dynamically weighted value of the satellite signal quality RSRP:

[0116] During the window duration, if And duration If so, then event A3 verification passes;

[0117] Among them, if ,but , ,but , , The first elevation angle threshold, The satellite elevation angle for user equipment and service satellites.

[0118] To ensure signal stability at high elevation angles, it is usually necessary to... Set to 2dB, because the signal is prone to fluctuation at low elevation angles and requires a high threshold, usually... Set to 4dB. First elevation angle threshold. It is usually set to 30°.

[0119] The process of switching to the target satellite includes:

[0120] Obtain a set of candidate satellites and filter out satellite elevation angles. Candidate satellites, This is the second elevation angle threshold, typically set to 20°.

[0121] Calculate the combined score of the remaining candidate satellites in the candidate satellite set. :

[0122]

[0123] In the formula, The 1st among the remaining candidate satellites The overall score of each candidate satellite Weighting coefficients for service quality and service duration; The 1st among the remaining candidate satellites The dynamic weighted value of the satellite signal quality RSRP of each candidate satellite and the remaining time available to serve user equipment; The maximum value of the candidate satellite's signal quality RSRP and service duration; signal quality has a higher weight than service duration. The values ​​are typically 0.7 and 0.3.

[0124] Select Overall Score highest and The candidate satellites were selected as the target satellites. This is the third weighted threshold value;

[0125] During the window duration, the user device switching time Allocation by elevation angle interval:

[0126]

[0127] In the formula, The window start time and window duration; The elevation angle between the user equipment and the target satellite is set to ensure that user equipment at different elevation angles is evenly distributed within the window, and the number of user equipment switched at the same time is ≤ 1 / F of the network capacity (F is a constant, such as 1 / 5).

[0128] Taking the user equipment handover scenario under the coverage of LEO satellites (orbital altitude 1000km, elevation angle change rate 0.08° / s) as an example, the specific implementation steps of the dual triggering mechanism of D1 event and T1 event are as follows:

[0129] (a) Parameter Configuration

[0130] Dynamic weighted model: K=0.9 (LEO coefficient), L=0.9 ( =40°≥30°);

[0131] Event D1: =80km, =60km, =3dB, T =50ms;

[0132] Event T1: duration = 5° / 0.08° / s = 62.5s. =2dB ( = 40°≥30°), =200ms;

[0133] Target selection: =0.3, .

[0134] (II) Implementation Process

[0135] User equipment obtains its own position via GNSS and combines this with ephemeris calculations to serve satellites. =40°, target satellite =50°;

[0136] Calculate weighted RSRP: serving satellites = RSRP f×sin40°×0.9×0.9, target satellite = RSRP m ×sin50°×0.9×0.9;

[0137] D1 event triggered: Distance condition is met, and the target satellite... Super Service Satellite If the 3dB level reaches 50ms, a trigger indication will be reported.

[0138] Within window T1, the UE detected that the weighted A3 event met the 200ms requirement within 62.5s, and then... =50° Calculate the sub-window time (UTC+34.7s);

[0139] Switched to the target satellite, verification successful.

[0140] or:

[0141] (a) Parameter Configuration

[0142] Dynamic elevation angle weighted model: Since the satellite type is LEO, the orbit coefficient K=0.9; the initial measurement service satellite elevation angle α=40° (≥30°) for user equipment, and the path loss correction factor L=0.9.

[0143] T1 event parameters: Window duration calculated based on elevation angle change rate: duration = 5° / 0.08° / s = 62.5s (ensuring elevation angle change within the window does not exceed 5°); weighted A3 event threshold. =2dB (high elevation angle signal stability, low threshold selected), continuous verification duration =200ms.

[0144] Target cell selection: Candidate satellites with α≥20° are screened, and the comprehensive scoring weights w1 (weighted RSRP) = 0.7 and w2 (remaining service time) = 0.3 are used to exclude low-elevation-angle inferior satellites.

[0145] (II) Implementation Process

[0146] Parameter distribution and ephemeris acquisition: The network distributes T1 event configuration (UTC time, duration=62.5s) to the user equipment. =2dB), synchronously push LEO satellite ephemeris (including orbital parameters and beam coverage dynamic range).

[0147] Elevation angle and weighted RSRP calculation: The user equipment obtains its real-time position via GNSS, and calculates the service satellite α=40° and the target satellite α=55° based on ephemeris data; the measurement service satellite RSRP=-98dBm and the target satellite RSRP=-97dBm. The weighted RSRP is then calculated using the formula:

[0148] Service satellite weighted: RSRP = -98dBm × sin40° × 0.9 × 0.9 ≈ -98dBm × 0.64 × 0.81 ≈ -50.8dBm;

[0149] Target satellite weighted average: RSRP = -97dBm × sin55° × 0.9 × 0.9 ≈ -97dBm × 0.82 × 0.81 ≈ -64.4dBm;

[0150] Trigger judgment within T1 window: The user equipment starts measurement at UTC time and detects that the weighted RSRP of the target satellite is lower than the weighted RSRP of the serving satellite, so the weighted A3 event cannot be triggered;

[0151] If a weighted A3 event is triggered, the sub-window allocation and handover execution is as follows: The UE calculates the handover time based on the current target satellite α=55° using the formula t_switch=UTC+(55° / 90°)×62.5s≈UTC+38.2s, and reports the handover request to the network at that time; after the network confirms, it sends the target cell configuration, and the UE completes the handover.

[0152] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0153] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0154] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0155] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0156] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A conditional handover method for NTN based on dynamic elevation angle weighting, characterized in that, include: Obtain D1 / T1 event configuration information, serving satellites, and target satellites' ephemeris from the NR network; Obtain the user equipment's own location and calculate the satellite elevation angles of the serving satellite and the target satellite by combining the satellite ephemeris; The signal quality RSRP of the serving satellite and the target satellite is obtained and dynamically weighted based on the satellite elevation angle, satellite type, and path loss; Based on the user equipment's own location, the dynamic weighting result, and the D1 / T1 event configuration information, A3 event verification is performed. If the A3 event is satisfied, the process of switching to the target satellite is initiated. Specifically, the D1 event configuration information includes a first threshold value. Second threshold value Weighted threshold and duration threshold ; A3 event verification based on the user equipment's own location, dynamic weighting results, and D1 event configuration information includes: The user equipment determines whether the D1 event is triggered based on its own location, dynamic weighting result, and D1 event configuration information. If the D1 event is triggered, the user equipment reports the D1 event to the NR network. The NR network verifies the legitimacy of the D1 event trigger. If the verification is successful, it configures the A3 event configuration information based on the dynamic weighted value of the satellite signal quality RSRP and sends it to the user equipment. User equipment performs A3 event verification based on the dynamic weighted value of the satellite signal quality RSRP: like And duration If so, then event A3 verification passes; In the formula, These are the dynamic weighted values ​​of the satellite signal quality RSRP for the target satellite and the service satellite, respectively. This is the duration threshold for event A3; Specifically, the T1 event configuration information includes the window start time, window duration, and weighted threshold value. Duration threshold of A3 event ; A3 event verification based on the dynamic weighting result and T1 event configuration information includes: Upon reaching the start time of the window, the user equipment performs A3 event verification based on the dynamically weighted value of the satellite signal quality RSRP: During the window duration, if And duration If so, then the A3 event verification is successful.

2. The NTN conditional handover method based on dynamic elevation angle weighting according to claim 1, characterized in that, The satellite elevation angle for: ； In the formula, The orbital altitude of the satellite. The altitude of the user equipment. This refers to the horizontal distance between the user equipment and the satellite's nadir point.

3. The NTN conditional handover method based on dynamic elevation angle weighting according to claim 1, characterized in that, The dynamic weighted value of the satellite signal quality RSRP for: ； In the formula, The satellite elevation angle. For orbital coefficients, This is the loss factor.

4. The NTN conditional handover method based on dynamic elevation angle weighting according to claim 3, characterized in that, If the satellite is an LEO satellite, then the orbital coefficient The value range is from 0.8 to 1.0; If the satellite is a MEO satellite, then the orbital coefficient The value range is from 0.6 to 0.8; If the satellite is a GEO satellite, then the orbital coefficient The value range is from 0.4 to 0.

6.

5. The NTN conditional handover method based on dynamic elevation angle weighting according to claim 3, characterized in that, like Then the loss factor The value range is from 0.8 to 1.0; like Then the loss factor The value range is from 0.6 to 0.8; like Then the loss factor The value is 0.

5.

6. The NTN conditional handover method based on dynamic elevation angle weighting according to claim 1, characterized in that, If the serving satellite is an LEO satellite, then If the serving satellite is a MEO satellite or a GEO satellite, then , .

7. The NTN conditional handover method based on dynamic elevation angle weighting according to claim 1, characterized in that, The determination of whether event D1 has been triggered includes: like and If so, then the distance condition is satisfied; like If so, then the weighting condition is met; like If the condition is met, the D1 event is triggered. In the formula, These are the spherical distances between the beam centers of the user equipment and the service satellite and the target satellite, respectively. This is the duration during which both the distance condition and the weighting condition are satisfied.

8. The NTN conditional handover method based on dynamic elevation angle weighting according to claim 1, characterized in that, like ,but , ,but , , The first elevation angle threshold, The satellite elevation angle for user equipment and service satellites.

9. The NTN conditional handover method based on dynamic elevation angle weighting according to claim 1, characterized in that, The process of switching to the target satellite includes: Obtain a set of candidate satellites and filter out satellite elevation angles. Candidate satellites, The second elevation angle threshold; Calculate the combined score of the remaining candidate satellites in the candidate satellite set. : ； In the formula, The 1st among the remaining candidate satellites The overall score of each candidate satellite Weighting coefficients for service quality and service duration; The 1st among the remaining candidate satellites The dynamic weighted value of the satellite signal quality RSRP of each candidate satellite and the remaining time available to serve user equipment; The maximum value of the satellite signal quality RSRP and service duration for the candidate satellites; Select Overall Score highest and The candidate satellites were selected as the target satellites. This is the third weighted threshold value; During the window duration, the user device switching time Allocation by elevation angle interval: ； In the formula, The window start time and window duration; The elevation angle between the user equipment and the target satellite.

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