Network handover method and apparatus

Abstract

This specification relates to the field of communication technology, and in particular to a network handover method and device. The network handover method includes: predicting whether a cross-satellite handover opportunity exists for the terminal device based on the terminal device's location information, first parameter information of the source satellite device, and second parameter information of the target satellite device; if so, triggering a handover process, wherein the handover process is used by the terminal device to initiate a handover to the target satellite device. The embodiments in this specification, through a satellite-side cross-satellite handover strategy, enable smooth handover to non-terrestrial networks when a terminal device needs to switch to a satellite that previously did not send paging messages.

Description

Technical Field

[0001] This specification relates to the field of communication technology, and in particular to a network switching method and device. Background Technology

[0002] Non-terrestrial networks (NTNs) are characterized by their large coverage area and flexible networking capabilities, providing ubiquitous coverage regardless of terrain. NTNs consist of a large number of satellites that can cover terminal devices. Of these satellites, only one or a group of satellites need to send paging messages to the terminal devices, eliminating the need for all satellites to send paging messages and thus reducing unnecessary communication overhead.

[0003] In some scenarios, terminal devices need to switch to satellites that did not previously send paging messages. For example, the terminal device may be in a fixed location, but due to certain reasons (such as weather), it may need to switch to a satellite that did not previously send paging messages. How to achieve cross-satellite handover is a technical problem that urgently needs to be solved. Summary of the Invention

[0004] This specification provides a network handover method, apparatus, and device for enabling cross-satellite handover of non-terrestrial networks.

[0005] This specification provides a network switching method, including:

[0006] Based on the location information of the terminal device, the first parameter information of the source satellite device, and the second parameter information of the target satellite device, predict whether the terminal device has a cross-satellite handover opportunity;

[0007] If present, a handover process is triggered, which is used by the terminal device to initiate a handover to the target satellite device.

[0008] This specification provides another network switching method, including:

[0009] Receive information sent by the source satellite device, which is sent by the source satellite device based on the location information of the terminal device, the first parameter information of the source satellite device, and the second parameter information of the target satellite device when a cross-satellite handover opportunity is predicted.

[0010] Based on the information provided, a handover is initiated to the target satellite equipment.

[0011] This specification also provides a terminal device. The terminal device includes a processor and a memory, the memory storing a computer program that can run on the processor, and the processor executing the computer program to implement the network switching method described above.

[0012] This specification also provides a satellite device. The satellite device includes a processor and a memory, the memory storing a computer program executable on the processor, which, when executed, implements the network handover method described above.

[0013] This specification also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described network switching method.

[0014] This specification also provides a computer program product, which includes a computer program that, when executed by a processor, implements the above-described network switching method.

[0015] The network handover method in the embodiments of this specification allows the source satellite device to predict whether there is an opportunity for cross-satellite handover based on the location information of the terminal device, the first parameter information of the source satellite device, and the second parameter information of the target satellite device. If such an opportunity exists, a handover process can be triggered, which is used by the terminal device to initiate a handover to the target satellite device.

[0016] Therefore, this embodiment of the specification, through a satellite-side cross-satellite handover strategy, allows the source satellite device to predict in advance whether it needs to switch the terminal device to a target satellite device in the adjacent satellite constellation to continue service after the terminal device connects to the source satellite device. If so, a handover process can be triggered. This embodiment of the specification, through a satellite-side cross-satellite handover strategy, enables smooth handover to non-terrestrial networks when the terminal device needs to switch to a satellite that previously did not send paging messages. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. The drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating the network switching method in the embodiments of this specification;

[0019] Figure 2 This is a flowchart illustrating the network switching method in the embodiments of this specification;

[0020] Figure 3 This is a schematic diagram of the track surface in the embodiments of this specification;

[0021] Figure 4This is a schematic plan view showing the terminal device and the source satellite device in the embodiments of this specification;

[0022] Figure 5 This is a flowchart illustrating the network switching method in the embodiments of this specification;

[0023] Figure 6 This is a schematic diagram of the network switching device in the embodiments of this specification;

[0024] Figure 7 This is a schematic diagram of the network switching device in the embodiments of this specification;

[0025] Figure 8 This is a flowchart illustrating the network switching method in the embodiments of this specification. Detailed Implementation

[0026] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. The specific embodiments described herein are only used to explain this disclosure, and not to limit this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure are within the scope of protection of this disclosure. In addition, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0027] The embodiments described in this specification can be applied to non-terrestrial network (NTN) communication systems. NTN communication systems can include satellite systems. Based on satellite altitude, i.e., orbital altitude, satellite systems can be classified as highly elliptical orbit (HEO) satellites, GEO satellites, medium-earth orbit (MEO) satellites, and low-Earth orbit (LEO) satellites. Furthermore, NTN communication systems can also include aerial network equipment such as high-altitude platform station (HAPS) communication systems.

[0028] In the embodiments described in this specification, terminal equipment (TE) may also be referred to as user equipment (UE), for example, as a device that accesses a communication network and receives network services through a network device. Terminal equipment can be fixed or mobile, and may also be referred to as a mobile station (MS), terminal, subscriber station (SS), access terminal (AT), etc.

[0029] In the embodiments of this specification, the terminal device may include, but is not limited to, the following devices: cellular phone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, machine-type communication device, laptop computer, cordless phone, smartphone, smartwatch, digital camera, etc. In scenarios such as the Internet of Things (IoT), the terminal device may also be a machine or device for monitoring or measurement, such as, but not limited to: machine-type communication (MTC) terminal, vehicle communication terminal, device-to-device (D2D) terminal, machine-to-machine (M2M) terminal, etc.

[0030] In the embodiments described in this specification, satellite equipment refers, for example, to equipment in a communication system that connects a terminal device to a communication network and provides services to that terminal device. Satellite equipment may include satellites, onboard base stations, etc.

[0031] This specification provides a network switching method through its embodiments. The method can be applied to source satellite equipment.

[0032] Please see Figure 1 , Figure 2 and Figure 8 The method may include the following steps.

[0033] Step 11: Based on the location information of the terminal device, the first parameter information of the source satellite device, and the second parameter information of the target satellite device, predict whether there is an opportunity for the terminal device to switch across satellites.

[0034] Step 12: If present, trigger the handover process, which is used by the terminal device to initiate a handover to the target satellite device.

[0035] In some embodiments, the source satellite device is a satellite device currently providing service to the terminal device. The target satellite device is a satellite device that is not currently providing service to the terminal device. The source satellite device and the target satellite device correspond to different networks. The terminal device can switch networks by switching from the source satellite device to the target satellite device. Optionally, the source satellite device and the target satellite device are in the same orbit. Optionally, both the source satellite device and the target satellite device are low-Earth orbit (LEO) satellite devices.

[0036] In non-terrestrial networks, there are numerous satellite devices that can cover terminal devices. Among these satellite devices, source satellite devices are those currently providing service to the terminal devices, while target satellite devices are those not currently providing service to the terminal devices. For example, a target satellite device might be one of the satellites in a cluster of satellites near the source satellite device. A cluster of satellites near the source satellite device includes one or more satellite devices that can cover the terminal devices but are not currently providing service to them.

[0037] In some embodiments, after a terminal device connects to a source satellite device, the source satellite device can select the nearest satellite device in the same orbit as the source satellite device as the target satellite device from the adjacent satellite constellation. Along the satellite device's direction of travel, the target satellite device is located behind the source satellite device. The source satellite device can predict whether a cross-satellite handover opportunity exists for the terminal device based on the terminal device's location information, the source satellite device's first parameter information, and the target satellite device's second parameter information; if so, it can trigger a handover procedure, which is used by the terminal device to initiate a handover to the target satellite device.

[0038] Therefore, when a cluster of neighboring satellites exists, the source satellite equipment can predict in advance whether it needs to switch the terminal equipment to one of the neighboring satellites to continue service, based on the terminal equipment's location information and its own parameter information. This prediction can be a one-time prediction by the source satellite equipment within the effective time of the satellite orbital elements. Of course, multiple predictions can also be made within the effective time of the satellite orbital elements. The effective time of the satellite orbital elements is determined by the requirements for satellite orbit determination accuracy and the accuracy of the actual switching time.

[0039] The source satellite device can make predictions when the location variable of the terminal device is less than or equal to a threshold. A location variable less than or equal to the threshold indicates that the terminal device's location is fixed and has not changed significantly. Alternatively, the source satellite device can also make predictions when the location change of the terminal device exceeds the threshold. Of course, the source satellite device can also make predictions at any time within the effective service period. This specification does not specifically limit this in the embodiments.

[0040] Optionally, if the source satellite does not exist, the source satellite device may not trigger the handover process. For example, the source satellite device may ignore the prediction results.

[0041] Optionally, if no target satellite is available, the source satellite may select another satellite in the adjacent satellite constellation that is in the same orbit as the source satellite and is closest to it, excluding the target satellite. This new target satellite will be positioned behind the source satellite along its direction of travel. The source satellite can predict whether a cross-satellite handover opportunity exists for the terminal device based on the terminal device's location information, the source satellite's first parameter information, and the new target satellite's second parameter information. If such an opportunity exists, a handover process can be triggered, allowing the terminal device to initiate a handover to the new target satellite. If no target satellite is available, the source satellite can iteratively execute the target satellite selection and prediction processes until a cross-satellite handover opportunity exists or the selection of satellites in the adjacent satellite constellation is complete.

[0042] In some embodiments, the location information is used to represent the location of the terminal device. The location information may include first coordinate data of the terminal device in a geodetic coordinate system. The first coordinate data may include one or more of latitude, longitude, and geodetic elevation. After the terminal device connects to a source satellite device, the terminal device can send its own location information to the source satellite device. The source satellite device can receive the location information sent by the terminal device.

[0043] In some embodiments, the first parameter information may include first satellite parameter information and first orbital parameter information of the source satellite equipment. The first satellite parameter information may include parameters representing the characteristics of the source satellite equipment, such as the maximum half-angle of beam service coverage of the source satellite equipment. The first orbital parameter information may include ephemeris parameter information of the source satellite equipment. The first orbital parameter information may include the orbital semi-major axis, angular velocity, and orbital eccentricity of the source satellite equipment.

[0044] In some embodiments, the second parameter information may include second satellite parameter information and second orbital parameter information of the target satellite device. The second satellite parameter information may include parameters representing the characteristics of the target satellite device, such as the maximum half-angle of beam service coverage of the target satellite device. The second orbital parameter information may include ephemeris parameter information of the target satellite device. The target satellite device may send the second parameter information to the source satellite device. The source satellite device may receive the second parameter information sent by the target satellite device. The second orbital parameter information may include the target satellite device's orbital semi-major axis, angular velocity, orbital eccentricity, etc.

[0045] In some embodiments, the source satellite device can calculate a first service boundary time based on its position information and first orbital parameter information; it can calculate a second service boundary time for the target satellite device based on its position information and second orbital parameter information; and it can predict whether there is an opportunity for cross-satellite handover based on the first and second service boundary times. The service boundary time is the edge moment of a satellite device's service, used to indicate the time when service begins and / or ends.

[0046] The first service boundary time may include the first handover time of the source satellite equipment. The second service boundary time may include the handover time of the target satellite equipment and / or the second handover time. The handover time is the time when the satellite equipment begins service. The handover time is the time when the satellite equipment ends service. The source satellite equipment can predict whether the terminal equipment meets the cross-satellite handover conditions; if so, it can trigger the handover process. The cross-satellite handover conditions may include: the first handover time is greater than or equal to the handover time, and less than or equal to the second handover time. For example, the cross-satellite handover conditions are expressed as follows: Indicates the first cut-out moment of the source satellite equipment. Indicates the cut-in time of the target satellite equipment. This indicates the second cut-out time of the target satellite equipment.

[0047] In some embodiments, the source satellite device can calculate the first critical half-angle of projection and the first included angle of projection based on its position information and the first orbital parameter information, respectively; and can calculate the first service boundary time based on the first critical half-angle of projection and the first included angle of projection. The first critical half-angle of projection is the critical half-angle of projection of the source satellite device on the orbital plane, and the first included angle of projection is the angle between the projections of the terminal device and the source satellite device on the orbital plane. The orbital plane is the plane in which the source satellite device orbits the Earth.

[0048] The first cut-out time of the source satellite equipment can be calculated in several ways.

[0049]

[0050] Indicates the first cut-out moment of the source satellite equipment. A This indicates the angular velocity of the source satellite equipment. θ represents the angle between the projected position of the terminal device on the orbital plane and the X-axis of the orbital plane coordinate system. The orbital plane is the plane in which the source satellite device orbits the Earth. The orbital plane coordinate system is a Cartesian coordinate system with the Earth's center as the origin, the direction from the Earth's center to the ascending node as the X-axis, and the direction normal to the orbital plane as the Z-axis. Th,A This represents the first critical half-angle of projection. Indicates the first projection angle.

[0051] In some embodiments, the source satellite device can calculate the second critical half-angle and the second projection angle based on the position information and the second orbital parameter information, respectively; and can calculate the second service boundary time based on the second critical half-angle and the second projection angle. The second critical half-angle is the critical half-angle of the target satellite device's projection on the orbital plane, and the second projection angle is the angle between the projections of the terminal device and the target satellite device on the orbital plane.

[0052] The cut-in and cut-out times of the target satellite equipment can be calculated in various ways.

[0053] For example, it can be done through formulas Calculate the cut-in time and the second cut-out time of the target satellite equipment.

[0054] This indicates the cut-in time of the target satellite equipment. This indicates the second cut-out time of the target satellite equipment. B This indicates the angular velocity of the target satellite equipment. θ represents the angle between the projected position of the terminal device on the track surface and the X-axis of the track surface coordinate system. Th,B This represents the second critical half-angle of the target satellite equipment's projection. This indicates the second projection angle of the target satellite equipment.

[0055] In some embodiments, the source satellite device can convert the first coordinate data into second coordinate data in the orbital plane coordinate system. The second coordinate data is used to represent the projected position of the terminal device on the orbital plane of the source satellite device. The source satellite device can calculate the first critical half-angle and the first projection angle based on the second coordinate data and the first orbital parameter information, respectively; and can calculate the second critical half-angle and the second projection angle based on the second coordinate data and the second orbital parameter information, respectively.

[0056] The source satellite equipment, based on the terminal equipment's first coordinate data, can obtain the terminal equipment's third coordinate data through celestial conversion; it can then convert the third coordinate data into fourth coordinate data; and finally, it can convert the fourth coordinate data into second coordinate data. The third coordinate data is the terminal equipment's coordinate data in the ECEF (Earth-Centered, Earth-Fixed) coordinate system. The ECEF coordinate system is a non-inertial coordinate system that rotates with the Earth. The fourth coordinate data is the terminal equipment's coordinate data in the ECI (Earth-Centered Inertial) coordinate system. The ECI coordinate system is an inertial coordinate system that does not rotate with the Earth. The fourth coordinate data can be determined based on the reference frame used for Kepler orbital elements (such as the instantaneous true time, the celestial coordinate system corresponding to the J2000 time). The source satellite equipment can convert the fourth coordinate data into second coordinate data based on Kepler orbital element parameters (such as low-Earth orbit satellite inclination, perigee argument, right ascension of the ascending node, orbital eccentricity, and orbital semi-major axis) using the Kepler celestial model.

[0057] In related technologies, a coordinate system is established with the Earth's center as the origin, the direction from the Earth's center to the perigee as the X-axis, and the direction normal to the orbital plane as the Z-axis, as the orbital plane coordinate system. The perigee is the point on the satellite's orbit closest to Earth. Due to measurement errors, orbital perturbations, and other factors, the actual perigee on the orbital plane may vary. The position of the perigee will differ under different times and measurement conditions. When different perigees are selected at different times, the orbital plane coordinate system will experience error jitter. This error jitter can lead to incorrect calculations of the satellite's instantaneous angular velocity. Therefore, in some embodiments of this specification, the orbital plane coordinate system is a Cartesian coordinate system with the Earth's center as the origin, the direction from the Earth's center to the ascending node as the X-axis, and the direction normal to the orbital plane as the Z-axis. By using the direction from the Earth's center to the ascending node as the X-axis, the error jitter problem of the orbital coordinate system can be avoided.

[0058] Please see Figure 3 . Figure 3 The orbital plane is shown. Figure 3 In this coordinate system, the X and Y axes are the X and Y axes of the track surface coordinate system. Point O represents the track center. Point M is the intersection of the normal line perpendicular to the track surface passing through the terminal device and onto the track surface. Point M represents the projected position of the terminal device on the track surface. The second coordinate data of the terminal device can be represented as [x...]. ue ,y ue ,z ue The projected coordinates of the terminal device on the track plane can be represented as [x]. ue ,y ue ].

[0059] In some embodiments of this example, the source satellite device can calculate the first projection critical half-angle based on its own beam service maximum coverage half-angle, orbital half-major axis, and second coordinate data. As an example, the source satellite device can use the formula... Calculate the first critical half-angle of projection. θ Th,A Indicates the first critical half-angle of projection. Γ A This indicates the maximum half-angle of beam service coverage for the source satellite equipment. A This indicates the semi-major axis of the source satellite equipment's orbit.

[0060] Please see Figure 4 . Figure 4 The plane formed by the terminal equipment and the source satellite equipment is shown. Figure 4 In the diagram, point A represents the source satellite equipment, point P represents the nadir point, point Q represents the terminal equipment, and Γ represents the terminal equipment. A This indicates the maximum half-angle of beam service coverage for the source satellite equipment. Figure 3 In the diagram, point A′ represents the location of the source satellite equipment at the maximum coverage half-angle of the beam service, and ∠A′OM represents the first critical half-angle of the projection.

[0061] The source satellite equipment can calculate the first projection angle based on the angle between its own position on the orbital plane and the X-axis of the orbital plane coordinate system, and the angle between the projected position of the terminal equipment on the orbital plane and the X-axis of the orbital plane coordinate system. As an example, the source satellite equipment can use the formula... Calculate the first projection angle. The angle represents the first projection angle at time t. This represents the angle between the position of the source satellite device on the orbital plane and the X-axis of the orbital plane coordinate system at time t. This represents the angle between the projected position of the terminal device on the orbital plane and the X-axis of the orbital plane coordinate system. t represents the current time, which can be used by the source satellite equipment to predict whether a cross-satellite handover opportunity exists for the terminal device. Figure 3 In the diagram, point A represents the position of the source satellite equipment at time t, and ∠AOM represents the first projection angle. OM is the angle between the X-axis and the X-axis. Let OA be the angle between the OA axis and the X-axis.

[0062] The source satellite device can calculate the angle between its position on the orbital plane and the X-axis of the orbital coordinate system based on its true angle of approximation, argument of perigee, and angular velocity. As an example, the source satellite device can be calculated using the formula... Calculate the angle between the position of the source satellite equipment on the orbital plane and the X-axis of the orbital plane coordinate system. A (t0) represents the true near angle of the source satellite at time t0. ω A(t0) represents the perigee argument of the source satellite at time t0. A This represents the angular velocity of the source satellite equipment. Time t0 can be the moment when the source satellite equipment last received ephemeris parameter information.

[0063] The source satellite equipment can calculate its own deviation angle based on its orbital eccentricity and instantaneous mean angle of approximation; it can also calculate its true angle of approximation based on its deviation angle of approximation. As an example, the source satellite equipment can use the formula θ... E (t0)=θ M (t0)+e·sin(θ E (t0)) Iteratively calculate its own deviation angle; it can be done through the formula Calculate its true near angle. θ E (t0) represents the proximity angle of the source satellite equipment at time t0. θ M (t0) represents the instantaneous mean angle of the source satellite at time t0. e represents the orbital eccentricity of the source satellite. T(t0) represents the true angle of the source satellite.

[0064] In some embodiments of this example, the source satellite device can calculate the second projection critical half-angle based on the target satellite device's beam service maximum coverage half-angle, orbital half-major axis, and second coordinate data. As an example, the source satellite device uses the formula... Calculate the critical half-angle of the second projection. θ Th,B This represents the critical half-angle of the second projection. Γ B This indicates the maximum half-angle of beam service coverage for the target satellite equipment. B This indicates the semi-major axis of the target satellite's orbit.

[0065] The source satellite equipment can calculate the second projection angle based on the angle between the target satellite equipment's position on the orbital plane and the X-axis of the orbital plane coordinate system, and the angle between the terminal equipment's projected position on the orbital plane and the X-axis of the orbital plane coordinate system. As an example, the source satellite equipment can use the formula... Calculate the included angle of the second projection. The angle between the second projections at time t is denoted as t. This represents the angle between the position of the target satellite device on the orbital plane and the X-axis of the orbital plane coordinate system at time t. This represents the angle between the projected position of the terminal device on the track surface and the X-axis of the track surface coordinate system. For example, in... Figure 3 In the diagram, point B represents the position of the target satellite equipment at time t, and ∠BOM represents the second projection angle. OB is the angle between the OB and the X-axis.

[0066] The source satellite equipment can calculate the angle between the target satellite equipment's position on the orbital plane and the X-axis of the orbital plane coordinate system based on the target satellite equipment's true angle of approximation, argument of perigee, and angular velocity. As an example, the source satellite equipment can use the formula... Calculate the angle between the position of the target satellite equipment on the orbital plane and the X-axis of the orbital plane coordinate system. B (t0) represents the true perimeter angle of the target satellite at time t0. ω B (t0) represents the perigee argument of the target satellite at time t0. B This indicates the angular velocity of the target satellite equipment.

[0067] The calculation process for the true angle of approximation of the target satellite is similar to that of the source satellite, and will not be repeated here.

[0068] In the embodiments described in the specification, the angle between a certain position on the track surface and the X-axis can be understood as the rotation angle when the X-axis rotates counterclockwise to that position. When the X-axis rotates to that position, it can be understood that the position is located on the X-axis by rotating the X-axis.

[0069] In some embodiments, after triggering the handover procedure, the source satellite device can send information to the terminal device. This information is used by the terminal device to initiate a handover to the target satellite device. As an example, the source satellite device can directly send this information to the terminal device. As another example, the source satellite device can send a handover request to the target satellite device. The target satellite device can send response information to the source satellite device according to the handover request. The source satellite device can send this information to the terminal device according to the response information. For example, the response information may include configuration information of the target satellite device. The configuration information may include, for example, Radio Resource Control (RRC) reconfiguration information of the target satellite device. The configuration information is used by the terminal device to handover to the target satellite device. The information sent by the source satellite device to the terminal device may carry the configuration information of the target satellite device.

[0070] In some embodiments, if a cross-satellite handover opportunity exists, the source satellite device can also calculate the cross-satellite handover time based on the location information of the terminal device, the first parameter information of the source satellite device, and the second parameter information of the target satellite device. The handover procedure triggered by the source satellite device is used by the terminal device to initiate a handover at the cross-satellite handover time.

[0071] The source satellite equipment can calculate the cross-satellite handover time based on the first projection angle and the second projection angle. As an example, the source satellite equipment can use formula t... switch =t+Δt switch Calculate the cross-satellite handover time. t switch Indicates the time of cross-satellite switching. Δt switch This indicates the time interval between the cross-satellite switching time and the current time.

[0072] In some embodiments, after the handover process is triggered, the source satellite device may send information to the terminal device. This information is used by the terminal device to initiate a handover to the target satellite device. This information may include the cross-satellite handover time.

[0073] The network handover method in the embodiments of this specification allows the source satellite device to predict whether there is an opportunity for cross-satellite handover based on the location information of the terminal device, the first parameter information of the source satellite device, and the second parameter information of the target satellite device. If such an opportunity exists, a handover process can be triggered, which is used by the terminal device to initiate a handover to the target satellite device.

[0074] Therefore, the embodiments in this specification employ a satellite-side cross-satellite handover strategy. After a terminal device connects to a source satellite device, the source satellite device can predict in advance whether it needs to switch the terminal device to a target satellite device in the adjacent satellite constellation to continue providing service. If so, a handover process can be triggered. This ensures a smooth handover to non-terrestrial networks even when the terminal device's location is fixed, but due to reasons such as weather, it needs to switch to a satellite device that did not previously provide service to the terminal device.

[0075] This specification provides a network switching method through its embodiments. The method can be applied to terminal devices.

[0076] Please see Figure 5 and Figure 2 The method may include the following steps.

[0077] Step 51: Receive information sent by the source satellite equipment.

[0078] Step 52: Based on the information, initiate a handover to the target satellite equipment.

[0079] In some embodiments, the information is sent by the source satellite device when a cross-satellite handover opportunity is predicted, based on the location information of the terminal device, the first parameter information of the source satellite device, and the second parameter information of the target satellite device.

[0080] The specific prediction process can be found in the previous examples, and will not be repeated here.

[0081] In some embodiments, the information may include a handover time. The terminal device may initiate a handover to the target satellite device at the handover time. For example, the information may include the handover time and the configuration information of the target satellite device. The terminal device may initiate a handover to the target satellite device at the handover time based on the configuration information of the target satellite device.

[0082] Therefore, the embodiments in this specification employ a satellite-side cross-satellite handover strategy. After a terminal device connects to a source satellite device, the source satellite device can predict in advance whether it needs to switch the terminal device to a target satellite device in the adjacent satellite constellation to continue providing service. If so, a handover process can be triggered. The terminal device can initiate a handover to the target satellite device based on the information sent by the source satellite device. This ensures a smooth handover even when the terminal device's location is fixed, but due to reasons such as weather, it needs to switch to a satellite device that did not previously provide service to the terminal device.

[0083] Please see Figure 6 This specification also provides a network switching device. The network switching device can be installed on the source satellite equipment. The network switching device may include the following units.

[0084] Prediction unit 61 is used to predict whether there is a cross-satellite handover opportunity for the terminal device based on the location information of the terminal device, the first parameter information of the source satellite device and the second parameter information of the target satellite device.

[0085] Triggering unit 62 is used to trigger a handover process if it exists, the handover process being used by the terminal device to initiate a handover to the target satellite device.

[0086] Please see Figure 7 This specification also provides another network switching device in its embodiments. The network switching device can be installed in a terminal device. The network switching device may include the following units.

[0087] The receiving unit 71 is used to receive information sent by the source satellite equipment. The information is sent by the source satellite equipment based on the location information of the terminal equipment, the first parameter information of the source satellite equipment, and the second parameter information of the target satellite equipment when a cross-satellite handover opportunity is predicted.

[0088] The switching unit 72 is used to initiate a handover to the target satellite equipment based on the information.

[0089] This specification also provides a terminal device. The terminal device includes a processor and a memory, the memory storing a computer program that can run on the processor, and the processor executing the computer program to implement the network switching method described above.

[0090] This specification also provides a satellite device. The satellite device includes a processor and a memory, the memory storing a computer program executable on the processor, which, when executed, implements the network handover method described above.

[0091] This specification also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described network switching method.

[0092] This specification also provides a computer program product, which includes a computer program that, when executed by a processor, implements the above-described network switching method.

[0093] Those skilled in the art will understand that this specification can be provided as a method, system, or computer program product. Therefore, this specification may take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware. Furthermore, this specification may 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.

[0094] This specification is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments thereof. It should 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. The computer may be a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email device, game console, tablet computer, wearable device, or any combination of these devices.

[0095] The functional units in the embodiments of this specification can be integrated into one processing unit, or each functional unit can exist physically separately, or two or more functional units can be integrated into one processing unit.

[0096] Those skilled in the art will understand that the descriptions of the various embodiments in this specification have different focuses, and parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments. Furthermore, it is understood that those skilled in the art, after reading this specification, can conceive of any combination of some or all of the embodiments listed in this specification without creative effort, and such combinations are also within the scope of disclosure and protection of this specification.

[0097] Although this specification has been described through embodiments, those skilled in the art will understand that the above embodiments are merely illustrative of the core ideas of this specification. Those skilled in the art will appreciate that many variations and modifications are possible with this specification. It is intended that the appended claims encompass these variations and modifications without departing from the spirit of this specification.

Claims

1. A network handover method, characterized in that, Applied to source satellite equipment, the method includes: Based on the location information of the terminal device, the first parameter information of the source satellite device, and the second parameter information of the target satellite device, predict whether the terminal device has a cross-satellite handover opportunity; If present, a handover process is triggered, which is used by the terminal device to initiate a handover to the target satellite device.

2. The method according to claim 1, characterized in that, The first parameter information includes the first orbital parameter information of the source satellite equipment, and the second parameter information includes the second orbital parameter information of the target satellite equipment; The prediction of whether the terminal device has an opportunity for cross-satellite handover includes: Based on the location information and the first orbital parameter information, calculate the first service boundary time of the source satellite equipment; Based on the location information and the second orbital parameter information, calculate the second service boundary time of the target satellite equipment; Based on the first service boundary time and the second service boundary time, predict whether there is an opportunity for cross-satellite handover.

3. The method according to claim 2, characterized in that, The first service boundary time includes the first cut-out time of the source satellite equipment, and the second service boundary time includes the cut-in time and the second cut-out time of the target satellite equipment; The prediction of whether there is an opportunity for cross-satellite switching includes: Predict whether the terminal device meets the cross-satellite handover conditions; the cross-satellite handover conditions include: the first handover time is greater than or equal to the handover time, and less than or equal to the second handover time.

4. The method according to claim 2, characterized in that, The first service boundary time of the computation source satellite equipment includes: Based on the location information and the first orbital parameter information, the first critical half-angle of projection and the first included angle of projection are calculated respectively. The first critical half-angle of projection is the critical half-angle of projection of the source satellite equipment on the orbital plane, and the first included angle of projection is the included angle of projection of the terminal equipment and the source satellite equipment on the orbital plane. The first service boundary time is calculated based on the first projection critical half angle and the first projection included angle.

5. The method according to claim 4, characterized in that, The location information includes the first coordinate data of the terminal device in geodetic coordinates; the method further includes: The first coordinate data is converted into second coordinate data in the orbital plane coordinate system. The second coordinate data is used to represent the projection position of the terminal device on the orbital plane of the source satellite device. The calculation of the first critical half-angle and the first included angle of projection includes: Based on the second coordinate data and the first orbital parameter information, the first projection critical half angle and the first projection included angle are calculated respectively.

6. The method according to claim 2, characterized in that, The calculation of the second service boundary time of the target satellite equipment includes: Based on the location information and the second orbital parameter information, the second critical half-angle of projection and the second projection angle are calculated respectively. The second critical half-angle of projection is the critical half-angle of projection of the target satellite equipment on the orbital plane, and the second projection angle is the projection angle between the terminal equipment and the target satellite equipment on the orbital plane. The second service boundary time is calculated based on the second projection critical half-angle and the second projection included angle.

7. The method according to claim 6, characterized in that, The location information includes the first coordinate data of the terminal device in geodetic coordinates; the method further includes: The first coordinate data is converted into second coordinate data in the orbital plane coordinate system. The second coordinate data is used to represent the projection position of the terminal device on the orbital plane of the source satellite device. The calculation of the second projection critical half-angle and the included angle of the second projection includes: Based on the second coordinate data and the second orbital parameter information, calculate the second projection critical half angle and the second projection included angle respectively.

8. The method according to claim 1, characterized in that, If present, the method further includes: Based on the location information of the terminal device, the first parameter information of the source satellite device, and the second parameter information of the target satellite device, the cross-satellite handover time is calculated, and the handover procedure is used by the terminal device to initiate a handover at the cross-satellite handover time.

9. The method according to claim 8, characterized in that, The calculation of the cross-satellite handover time includes: Calculate the cross-satellite switching time based on the first projection angle and the second projection angle; Wherein, the first projection angle is the projection angle between the terminal device and the source satellite device on the orbital plane, and the second projection angle is the projection angle between the terminal device and the target satellite device on the orbital plane.

10. The method according to claim 1, characterized in that, The source satellite equipment and the target satellite equipment are in the same orbit.

11. The method according to claim 1, characterized in that, If present, the method further includes: Send a handover request to the target satellite equipment; The triggering switching process includes: Upon receiving the response information of the handover request sent by the target satellite equipment, the handover process is triggered.

12. The method according to claim 1, characterized in that, The method further includes: Send information for the terminal device to initiate a handover to the target satellite device.

13. A network handover method, characterized in that, Applied to a terminal device, the method includes: Receive information sent by the source satellite device, which is sent by the source satellite device based on the location information of the terminal device, the first parameter information of the source satellite device, and the second parameter information of the target satellite device when a cross-satellite handover opportunity is predicted. Based on the information provided, a handover is initiated to the target satellite equipment.

14. The method according to claim 13, characterized in that, The information includes the switching time; The initiation of a handover to the target satellite equipment includes: At the switching time, a handover is initiated to the target satellite equipment.

15. A terminal device, characterized in that, The terminal device includes a processor and a memory, the memory being used to store a computer program that can run on the processor, and the processor executing the computer program to implement the method of any one of claims 13 to 14.

16. A satellite device, characterized in that, The satellite device includes a processor and a memory, the memory being used to store a computer program that can run on the processor, the processor executing the computer program to implement the instructions of any of the methods described in claims 1 to 12.

17. A computer storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method described in any one of claims 1 to 14.

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