RU2801689C2 - Switching method and device in satellite communications - Google Patents

Abstract

FIELD: satellite communications.

SUBSTANCE: invention is aimed to reduce the power consumption of the terminal device, save radio interface resources and additionally prevent excessively large signalling due to the fact that a large number of terminal devices report measurement information at the same time, thereby increasing the proportion of successful handovers. It is achieved by the fact that in the handover method in satellite communications, the terminal device determines, based on the ephemeris information, the final satellite base station to which the terminal device needs to handover, the terminal device determines based on a certain final satellite base station of the first time, in which the terminal device needs to handover to the destination satellite base station, and handover by the terminal device based on the determined first time to the destination cell served by the destination satellite base station.

EFFECT: reducing the power consumption of the terminal device, saving radio interface resources and additionally prevent excessively large signalling due to the fact that a large number of terminal devices report measurement information at the same time, thereby increasing the proportion of successful handovers.

18 cl, 7 dwg, 1 tbl

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

[0001] The present application relates to communication technologies and, in particular, to a method and apparatus for handover in satellite communications.

BACKGROUND OF THE INVENTION

[0002] Geostationary satellites have long been used for mobile communications. However, geostationary satellites depend on the Geosynchronous Satellite Orbit (GSO). Therefore, a limited number of satellites can be deployed on a GSO. As an alternative solution to geostationary satellites, a communications system has been developed that uses a constellation of satellites in a Non Geosynchronous Satellite Orbit (NGSO), such as Low Earth Orbit (LEO), to provide coverage of the entire Earth or most points on earth. In a NGSO-based communication system, a satellite moves relative to a communication device (eg, gateway or terminal device) on the surface of the Earth. In addition, the communication device on the surface of the Earth may also be in a state of motion. For example, the communication device is on a moving high speed train or aircraft. For example, a satellite in low Earth orbit is moving relatively fast and is 1200 km above the Earth's surface. The satellite then takes about 100 minutes to complete one revolution around the Earth. In this case, the satellite serves the terminal device for about 10 minutes. Therefore, the terminal device can perform a handover from one satellite to another satellite at a particular point in time.

[0003] In the handover process of a terminal device in the related technology, the base station instructs the terminal device to perform a channel quality measurement. Then, based on the measurement result, the base station instructs the terminal apparatus to perform handover over the wireless link to the final neighbor cell.

[0004] However, in satellite communications, there is a relatively large transmission delay between the satellite and the terminal device because the distance between the satellite and the terminal device is relatively large, which is typically about 1000 km. In addition, the satellite is also in high-speed motion. Therefore, when the terminal device reports the measurement result, it is very likely that when the satellite receives the measurement result reported by the terminal device, the channel quality will change significantly due to the following two factors: transmission delay and satellite high speed traffic. In addition, the motion of the satellite results in frequent handover of the terminal device, and the terminal device needs to repeatedly report the measurement results. Not only does this increase the power consumption of the terminal device, but it can also cause excessive signaling in the system, eventually resulting in a handover failure.

SUMMARY OF THE INVENTION

[0005] The present application provides a satellite communication handover method and apparatus to reduce the power consumption of a terminal device, save air interface resources, and further avoid excessively large signaling caused by a large number of terminal devices reporting measurement information at the same time, thereby increasing the proportion of successful handovers.

[0006] According to a first aspect, the present application provides a handover method in satellite communication, including: A terminal device obtains ephemeris information of first satellite base stations. The first satellite base stations are satellite base stations that cover a terminal device. Based on the ephemeris information, the terminal apparatus determines the target satellite base station to which the terminal apparatus needs to perform a handover. The terminal apparatus determines, based on the determined target satellite base station, the first time at which the terminal apparatus needs to perform a handover to the target satellite base station. The terminal device performs a handover based on the determined first time to the target cell served by the target satellite base station.

[0007] In this embodiment, the terminal device determines the target satellite base station based on the location information of the satellite base stations, and determines the time for handover to the target satellite base station. The terminal device performs handover to the target cell served by the target satellite base station when the time comes. The satellite orbits periodically, so the handoff information determined by the terminal also assumes periodicity. In addition, the terminal device may not calculate the handover time in the disconnected state. Therefore, the terminal device does not need to frequently measure the channel quality and report the result of the measurement. This reduces the power consumption of the terminal device, saves radio interface resources, and further avoids excessive signaling caused by a large number of terminal devices reporting measurement information at the same time. Moreover, there is a relatively high probability that the handover decided and managed by the network side fails because the satellite and the terminal are in motion. However, the percentage of successful handovers can be increased when the target satellite base station and the handover time are selected by the terminal device.

[0008] In an exemplary embodiment, that the terminal device obtains the ephemeris information of the first satellite base stations includes the following: The terminal device sends an ephemeris information request to the ephemeris information network element, wherein the ephemeris information request includes location information of the terminal device . The terminal apparatus receives the signaling sent by the ephemeris information network element, the signaling including the ephemeris information of the first satellite base stations.

[0009] In an exemplary embodiment, that the terminal device determines, based on the ephemeris information, the destination satellite base station to which the terminal device needs to handover includes the following: The terminal device calculates a second time based on the ephemeris information, wherein the second time is the start time of coverage of the terminal device by satellite base stations covering the terminal device. The terminal apparatus determines the second satellite base stations based on the second time, wherein the second satellite base stations are satellite base stations to cover the terminal apparatus after the current moment. The terminal device calculates the distances between the second satellite base stations and the terminal device based on the ephemeris information of the second satellite base stations and the location information of the terminal device, and determines the nearest satellite base station of the second satellite base stations as the target satellite base station.

[0010] In an exemplary embodiment, what the terminal device determines based on the determined target satellite base station, the first time at which the terminal device needs to handover to the target satellite base station includes the following: The terminal device calculates the movement speed of the target satellite base station base station based on the ephemeris information of the destination satellite base station, and calculates the first time based on the movement speed of the destination satellite base station, the movement speed of the terminal apparatus, and the predetermined handover advance.

[0011] In an exemplary embodiment, what the terminal device obtains the ephemeris information of the first satellite base stations includes the following: The terminal device receives a broadcast message, wherein the broadcast message includes the identification information of the first satellite base stations and the identification information, times coverage and longitude and latitude information, which are related to the cells included in the first satellite base stations, and for the coverage times of the cells included in the first satellite base stations, cover the locations represented by the longitude and latitude information.

[0012] In an exemplary embodiment, that the terminal device determines, based on the ephemeris information, the target satellite base station to which the terminal device needs to handover includes the following: The terminal device determines, based on the identification information of the first satellite base stations and the identification information, coverage times, and longitude and latitude information that relate to cells included in the first satellite base stations, a cell that relates to cells included in the first satellite base stations and which covers the terminal device first; and determines, as the target satellite base station, the base station to which the cell that first covers the terminal device belongs.

[0013] In an exemplary embodiment, what the terminal device determines based on the determined target satellite base station, the first time at which the terminal device needs to handover to the target satellite base station includes: The terminal device calculates the first time based on the time coverage of the target satellite base station and a predetermined handover advance.

[0014] In an exemplary embodiment, a broadcast message is sent to one of the first satellite base stations, or a broadcast message is sent to each of the first satellite base stations.

[0015] According to a second aspect, the present application provides a satellite communication handover apparatus, including: a transceiver unit configured to receive ephemeris information from first satellite base stations, the first satellite base stations being satellite base stations that cover a terminal device; and a processing unit, configured to: determine, based on the ephemeris information, the target satellite base station to which the terminal device needs to perform a handover; determine, based on the determined target satellite base station, the first time at which the terminal apparatus needs to perform a handover to the target satellite base station; and perform handover based on the determined first time to the target cell served by the target satellite base station.

[0016] In this embodiment, the terminal device determines the target satellite base station based on the location information of the satellite base stations, and determines the time for handover to the target satellite base station. The terminal device performs handover to the target cell served by the target satellite base station when the time comes. The satellite orbits periodically, so the handoff information determined by the terminal also assumes periodicity. In addition, the terminal device may not calculate the handover time in the disconnected state. Therefore, the terminal device does not need to frequently measure the channel quality and report the result of the measurement. This reduces the power consumption of the terminal device, saves radio interface resources, and further avoids excessive signaling caused by a large number of terminal devices reporting measurement information at the same time. Moreover, there is a relatively high probability that the handover decided and managed by the network side fails because the satellite and the terminal are in motion. However, the percentage of successful handovers can be increased when the target satellite base station and the handover time are selected by the terminal device.

[0017] In an exemplary embodiment, the transceiver unit is specifically configured to: send a request for ephemeris information to an ephemeris information network element, wherein the request for ephemeris information includes location information of the terminal device; and receiving the signaling sent by the network element of the ephemeris information, the signaling including the ephemeris information of the first satellite base stations.

[0018] In an exemplary embodiment, the processing unit is specifically configured to: calculate a second time based on the ephemeris information, the second time being the start time of coverage of the terminal device by satellite base stations covering the terminal device; determine the second satellite base stations based on the second time, while the second satellite base stations are satellite base stations that should cover the terminal device after the current moment; and calculate distances between the second satellite base stations and the terminal device based on the ephemeris information of the second satellite base stations and the location information of the terminal device, and determine the nearest satellite base station of the second satellite base stations as the target satellite base station.

[0019] In an exemplary embodiment, the processing unit is specifically configured to calculate the target satellite base station's movement rate based on the target satellite base station's ephemeris information, and calculate the first time based on the target satellite base station's movement rate, the terminal device's movement rate, and the predetermined handover advance. .

[0020] In an exemplary embodiment, the transceiver unit is specifically configured to receive a broadcast message, wherein the broadcast message includes identification information of the first satellite base stations and identification information, coverage times, and longitude and latitude information that relate to cells included in the first satellite base stations, and for cell coverage times included in the first satellite base stations, cover locations represented by longitude and latitude information.

[0021] In an exemplary embodiment, the processing unit is specifically configured to: determine, based on the identification information of the first satellite base stations and the identification information, coverage times, and longitude and latitude information related to the cells included in the first satellite base stations, a cell which refers to the cells included in the first satellite base stations and which covers the terminal device first; and determine, as the target satellite base station, the base station to which the cell that first covers the terminal device belongs.

[0022] In an exemplary embodiment, the processing unit is specifically configured to calculate the first time based on the coverage time of the target satellite base station and the predetermined handover advance.

[0023] In an exemplary embodiment, a broadcast message is sent to one of the first satellite base stations, or a broadcast message is sent to each of the first satellite base stations.

[0024] According to a third aspect, the present application provides a terminal device including: one or more processors; and a memory adapted to store the one or more programs, wherein when the one or more programs are executed by the one or more processors, the method according to any one of the first aspect is implemented by the one or more processors.

[0025] According to a fourth aspect, the present application provides a computer-readable storage medium including a computer program, wherein when the computer program is executed on the computer, the computer executes the method according to any embodiment of the first aspect or possible implementations of the first aspect.

[0026] According to a fifth aspect, the present application provides a computer program, wherein when the computer program is executed by a computer, the computer program is adapted to perform a method according to any of the first aspect or embodiments of the first aspect.

[0027] According to a sixth aspect, the present application provides a chip including a processor and a memory, wherein the memory is adapted to store a computer program, and the processor is configured to call and run the computer program stored in the memory to perform a method according to any embodiment of the first aspect. or possible implementations of the first aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic diagram of a handover of a terminal device due to the movement of satellites in low orbit;

[0029] Figure 2 is a schematic diagram of a satellite communication scenario according to the present application;

[0030] FIG. 3 is a flowchart of the 1st embodiment of the satellite communication handover method according to the present application;

[0031] FIG. 4 is a flowchart of the 2nd embodiment of the handover method in satellite communications according to the present application;

[0032] FIG. 5 is a schematic block diagram of a communications device 500 according to the present application;

[0033] FIG. 6 is a block diagram of a terminal device 600 according to the present application; And

[0034] Figure 7 shows a block diagram of a network device 700 according to the present application.

DESCRIPTION OF EMBODIMENTS

[0035] In order to make the objectives, technical solutions and advantages of the present application more clear, the following clearly and completely describes the technical solutions in this application with reference to the accompanying drawings in this application. It is clear that the described embodiments are only part and not all of the present application. All other embodiments obtained by a person skilled in the art based on the embodiments in this application without creative effort should fall within the protection scope of this application.

[0036] FIG. 1 is a schematic diagram of a handover of a terminal device due to movement of satellites in low orbit. As shown in Fig. 1, due to the movement of the satellites, the location where the terminal device is located is covered by satellite 1 at time 1. At time 2, satellite 1 has moved to another location, and the location where the terminal device is located is covered by satellite 2. At time 3, satellite 2 has also moved to another location, and the location where the terminal device is located is covered by satellite 3. Therefore, the access service is provided to the terminal device by different satellites at different times. In this process, the terminal device needs to perform handover between cells of different satellites.

[0037] FIG. 2 is a schematic diagram of a satellite communication scenario according to the present application. As shown in figure 2, the present application relates to the field of satellite communications. A terminal device located on Earth accesses the network through New Radio (NR) technology. The base station is deployed on the satellite and connected to the ground station on Earth and the 5G core network via a radio link. There is also a radio link between the satellite base stations to complete the interworking of signaling and transmission of user data between the base stations. A terminal device is an NR-enabled mobile device including a mobile phone, a tablet computer, and the like. The terminal device can access the satellite base station via NR and initiate services such as calls and web browsing. The satellite base station mainly provides a radio access service, schedules a radio resource for a terminal device, and supports a reliable radio transmission protocol, a data encryption protocol, and the like. The 5G core network is mainly responsible for access control, mobility management, session management, user security authentication, charging and other terminal device services. The ground station is mainly responsible for forwarding signaling and service data between the satellite base station and the 5G core network. NR is a radio link between a terminal device and a satellite base station. The Xn interface is an interface between satellite base stations, which is basically capable of interworking signaling for handover and the like. The NG interface is the interface between the satellite base station and the 5G core network, which mainly exchanges 5G core network signaling and terminal device service data.

[0038] The following describes the satellite communication handover method provided in the present application using the scenario shown in FIG. 2 as an example.

[0039] FIG. 3 is a flowchart of the 1st embodiment of the satellite communication handover method according to the present application. As shown in FIG. 3, the method in this embodiment may be performed by a terminal device. The method may include the following steps.

[0040] Step 301: The terminal device sends an ephemeris information request to the ephemeris information network element.

[0041] The request for ephemeris information includes location information of the terminal device. The ephemeris information network element is configured to collect ephemeris information from all satellite base stations. The ephemeris information network element may be a network side device independent of the satellite base station and the 5G core network, or may be located in the 5G core network (as shown in FIG. 2).

[0042] Step 302: The ephemeris information network element sends a signaling to the terminal apparatus, the signaling including the ephemeris information of the first satellite base stations.

[0043] The first satellite base stations are satellite base stations that cover the terminal apparatus. The ephemeris information includes the angle of inclination of the satellite's orbital plane, the right ascension of the ascending node, the semi-major axis of the orbital ellipse, the eccentricity of the orbital ellipse, the angular distance of the perigee, the moment at which the satellite passes perigee, and the like.

[0044] Step 303: Based on the ephemeris information, the terminal device determines the target satellite base station to which the terminal device needs to handover.

[0045] If the terminal device detects that the signal of the serving base station has weakened, for example, the bit error rate of the signal received from the serving base station exceeds a predetermined threshold, then this indicates that the serving base station is now moving away from the terminal, and the signal strength is weakening . If the handover is not performed in a timely manner, the terminal apparatus may go offline. In this case, the terminal device can calculate the second time based on the previously acquired ephemeris information. The second time is the start time of coverage of the terminal device by satellite base stations covering the terminal device. The terminal apparatus then determines the second satellite base stations based on the second time. The second satellite base stations are satellite base stations to cover the terminal device after the current moment. Finally, the terminal apparatus calculates the distances between the second satellite base stations and the terminal apparatus based on the ephemeris information of the second satellite base stations and the location information of the terminal apparatus, and determines the nearest satellite base station of the second satellite base stations as the target satellite base station.

[0046] Based on the ephemeris information obtained in step 302, the terminal device can obtain the trajectory of each satellite base station that can cover the terminal device and the initial coverage times of the terminal device by satellite base stations, and can even determine the satellite base stations that should to move away from the terminal device, and the satellite base stations to be moved to the terminal device. The terminal device may determine M second satellite base stations from the N first satellite base stations based on the ephemeris information. The satellite base station has a fixed trajectory. Therefore, depending on the directions of movement, there are satellite base stations moving towards the terminal device and satellite base stations moving away from the terminal device. The terminal device first excludes the satellite base stations moving away from the terminal device and only stores the satellite base stations moving towards the terminal device, that is, the satellite base stations that should cover the terminal device after the current moment. Then, the terminal device calculates the distances between the M second satellite base stations and the terminal device based on the ephemeris information of the M second satellite base stations and the location information of the terminal device, and determines the nearest satellite base station M of the second satellite base station as the target satellite base station. Assuming that the location of the terminal device is P0, P0 can be obtained using the location device. The locations M of the second satellite base stations are respectively P1, P2, ... and PM. P1, P2, ... and PM can be obtained based on the ephemeris information of the second satellite base stations. The terminal device separately calculates the distances D1, D2, D3, ... and DM from the second satellite base stations, and selects the second satellite base stations with the shortest distance as the target satellite base station (target gNB) to which to handover.

[0047] Step 304: Based on the determined target satellite base station, the terminal device determines the first time at which the terminal device needs to perform a handover to the target satellite base station.

[0048] In the present application, the terminal device calculates the movement speed of the destination satellite base station based on the ephemeris information of the destination satellite base station, and calculates the first time based on the movement speed of the destination satellite base station, the movement speed of the terminal device, and the predetermined handover advance.

[0049] A round trip delay occurs when a signal is transmitted between a terminal device and a satellite base station. Therefore, when calculating the handover time, the terminal device additionally needs to take into account the signal transmission delay, that is, subtract the handover advance from the actual handover time. The handover advance may be set in consideration of factors such as transmission distance, transmission rate, and signal transmission delay.

[0050] Step 305: The terminal device performs a handover based on the determined first time to the target cell served by the target satellite base station.

[0051] In this embodiment, the terminal device receives the synchronization signal when the first time arrives and determines the destination cell based on the synchronization signal. The cell served by the target satellite base station externally sends a broadcast message and a synchronization signal. After receiving the synchronization signal, the terminal device considers that the condition for accessing the cell is satisfied, and then confirms that the cell is the destination cell.

[0052] The terminal device may directly send a handover request to the serving cell. The handover request includes the identification information of the target satellite base station and the identification information of the target cell. The handover request sent by the terminal device to the serving cell can be implemented in two ways: One is to add a handover request message, wherein the handover request message carries the identification information of the destination satellite base station and the identification information of the destination cell. Another is to add a new trigger event, such as Ax, to an existing measurement event. The terminal apparatus adds the identification information of the destination satellite base station and the identification information of the destination cell to the measurement event.

[0053] In this embodiment, the terminal device determines the target satellite base station based on the location information of the satellite base stations, and determines the time for handover to the target satellite base station. The terminal device performs handover to the target cell served by the target satellite base station when the time comes. The satellite orbits periodically, so the handoff information determined by the terminal also assumes periodicity. In addition, the terminal device may not calculate the handover time in the disconnected state. Therefore, the terminal device does not need to frequently measure the channel quality and report the result of the measurement. This reduces the power consumption of the terminal device, saves radio interface resources, and further avoids excessive signaling caused by a large number of terminal devices reporting measurement information at the same time. Moreover, there is a relatively high probability that the handover decided and managed by the network side fails because the satellite and the terminal are in motion. However, the percentage of successful handovers can be increased when the target satellite base station and the handover time are selected by the terminal device.

[0054] Figure 4 shows a flowchart of the 2nd embodiment of the handover method in satellite communications according to the present application. As shown in FIG. 4, the method in this embodiment may include the following steps.

[0055] Step 401: The terminal device receives a broadcast message.

[0056] The broadcast message may be sent by one of the satellite base stations that cover the terminal device, or may be sent by each of the satellite base stations that cover the terminal device. The satellite base station can obtain its ephemeris information from the core network, where the ephemeris information includes the satellite's orbital plane inclination, the right ascension of the ascending node, the semi-major axis of the orbital ellipse, the eccentricity of the orbital ellipse, the angular distance of perigee, the moment at which the satellite passes perigee , and so on. and obtains the ephemeris information of the neighboring satellite base station based on communication with the neighboring satellite base station. Therefore, the satellite base station can calculate an area coverage time based on the ephemeris information. The satellite base station may send the calculation result to the terminal as a broadcast message.

[0057] The broadcast message includes identification information of the first satellite base stations that cover the terminal device and identification information, coverage times, and longitude and latitude information that are related to cells included in the first satellite base stations. Over the coverage times, the cells included in the first satellite base stations cover the locations represented by the longitude and latitude information. For example, a broadcast message may be represented as shown in Table 1.

Table 1

Satellite base station identification information Cell Identification Information Coverage time Longitude Latitude ID 1gNB ID 1 cell 9:00-9:05 23°26'22"W 23°26'22" S ID 2gNB ID 2 cells 9:05-9:10 23°26'22"W 23°26'22" S ID 3gNB ID 3 cells 9:10-9:15 23°26'22"W 23°26'22" S

[0058] Step 402: Based on the ephemeris information, the terminal device determines the target satellite base station to which the terminal device needs to perform a handover.

[0059] Based on the identification information of the first satellite base stations and the identification information, coverage times, and longitude and latitude information that are related to the cells included in the first satellite base stations, the terminal device determines a cell that is related to the cells included in the first satellite base stations. base stations, and which first covers the terminal device; and determines, as the target satellite base station, the base station to which the cell that first covers the terminal device belongs.

[0060] Table 1 shows that a total of three satellite base stations (which are 5G base stations (Next Generation Node B (gNB)) in turn cover the location represented by longitude 23°26'22"W. and a latitude of 23°26'22" south latitude. The terminal device may obtain its location via a positioning device such as a Global Positioning System (GPS). Based on the information in Table 1, the terminal device can know that the location represented by longitude 23°26'22"W and latitude 23°26'22"S is its own location, thereby determining the coverage time to cover the location where the terminal device is located by the three cells in Table 1. The terminal device determines as the destination cell the cell that first covers the location where the terminal device is located among the cells, for example, cell ID 1. The base station to which the end cell belongs is the end satellite base station.

[0061] Step 403: Based on the determined target satellite base station, the terminal device determines the first time at which the terminal device needs to perform a handover to the target satellite base station.

[0062] The terminal apparatus calculates the first time based on the coverage time of the target satellite base station and the given handover advance. A round trip delay occurs when a signal is transmitted between a terminal device and a satellite base station. Therefore, when calculating the handover time, the terminal device additionally needs to take into account the signal transmission delay, that is, subtract the handover advance from the actual handover time. The handover advance may be set in consideration of factors such as transmission distance, transmission rate, and signal transmission delay.

[0063] Step 404: The terminal device performs a handover based on the determined first time to the target cell served by the target satellite base station.

[0064] The terminal device sends a handover request to the serving cell. The handover request includes the identification information of the target satellite base station and the identification information of the target cell. The handover request sent by the terminal device to the serving cell can be implemented in two ways: One is to add a handover request message, wherein the handover request message carries the identification information of the destination satellite base station and the identification information of the destination cell. Another is to add a new trigger event, such as Ax, to an existing measurement event. The terminal apparatus adds the identification information of the destination satellite base station and the identification information of the destination cell to the measurement event.

[0065] In this embodiment, the terminal device determines the target satellite base station based on the location information of the satellite base stations, and determines the time for handover to the target satellite base station. The terminal device performs handover to the target cell served by the target satellite base station when the time comes. The satellite orbits periodically, so the handoff information determined by the terminal also assumes periodicity. In addition, the terminal device may not calculate the handover time in the disconnected state. Therefore, the terminal device does not need to frequently measure the channel quality and report the result of the measurement. This reduces the power consumption of the terminal device, saves radio interface resources, and further avoids excessive signaling caused by a large number of terminal devices reporting measurement information at the same time. Moreover, there is a relatively high probability that the handover decided and managed by the network side fails because the satellite and the terminal are in motion. However, the percentage of successful handovers can be increased when the target satellite base station and the handover time are selected by the terminal device.

[0066] After receiving the handover request, the serving cell learns about the target satellite base station and the target cell through analysis (parsing), and sends a handover request to the target cell through the Xn interface, thereby starting the handover process provided in the 3rd partnership project generation (3rd Generation Partnership Project (3GPP)).

[0067] FIG. 5 is a schematic block diagram of a communications device 500 according to the present application. The communication device 500 includes a processing unit 502 and a transceiver unit 501.

[0068] In one embodiment, communication device 500 has a terminal device handover function in satellite communications in embodiments of the method. For example, the communication device 500 may fully correspond to the terminal device in the embodiment of FIG. 3 or FIG. 4. In this case, the blocks of the communication device 500 are adapted to perform the following operations and/or processing.

[0069] The transceiver unit 501 is configured to receive ephemeris information of the first satellite base stations, wherein the first satellite base stations are satellite base stations that cover the terminal apparatus.

[0070] The processing unit 502 is configured to determine, based on the ephemeris information, the target satellite base station to which the terminal device needs to handover; determine, based on the determined target satellite base station, the first time at which the terminal apparatus needs to perform a handover to the target satellite base station; and perform handover based on the determined first time to the target cell served by the target satellite base station.

[0071] In an exemplary embodiment, the transceiver unit 501 is specifically configured to: send a request for ephemeris information to an ephemeris information network element, wherein the request for ephemeris information includes location information of the terminal device; and receiving the signaling sent by the network element of the ephemeris information, the signaling including the ephemeris information of the first satellite base stations.

[0072] In an exemplary embodiment, the processing unit 502 is specifically configured to: calculate a second time based on the ephemeris information, the second time being the start time of coverage of the terminal device by satellite base stations covering the terminal device; determine the second satellite base stations based on the second time, while the second satellite base stations are satellite base stations that should cover the terminal device after the current moment; and calculate distances between the second satellite base stations and the terminal device based on the ephemeris information of the second satellite base stations and the location information of the terminal device, and determine the nearest satellite base station of the second satellite base stations as the target satellite base station.

[0073] In an exemplary embodiment, the processing unit 502 is specifically configured to calculate the movement speed of the target satellite base station based on the ephemeris information of the target satellite base station, and calculate the first time based on the movement speed of the target satellite base station, the movement speed of the terminal apparatus, and the predetermined transmission advance. service.

[0074] In an exemplary embodiment, the transceiver unit 501 is specifically configured to receive a broadcast message, wherein the broadcast message includes identification information of the first satellite base stations and identification information, coverage times, and longitude and latitude information that are related to the cells included into the first satellite base stations, and over the coverage times, the cells included in the first satellite base stations cover the locations represented by the longitude and latitude information.

[0075] In an exemplary embodiment, the processing unit 502 is specifically configured to: determine, based on the identification information of the first satellite base stations and identification information, coverage times, and longitude and latitude information that relate to cells included in the first satellite base stations, a cell , which refers to the cells included in the first satellite base stations, and which first covers the terminal device; and determine, as the target satellite base station, the base station to which the cell that first covers the terminal device belongs.

[0076] In an exemplary embodiment, the processor 502 is specifically configured to calculate the first time based on the coverage time of the target satellite base station and the predetermined handover advance.

[0077] In an exemplary embodiment, a broadcast message is sent to one of the first satellite base stations, or a broadcast message is sent to each of the first satellite base stations.

[0078] Optionally, communication device 500 may also have other functions in method embodiments. For such a description, refer to the previous description of the method embodiments. To avoid repetition, details are again omitted here.

[0079] Optionally, the processing unit 502 may be a processor and the transceiver unit 501 may be a transceiver. The transceiver includes a receiver and a transmitter and performs the functions of transmitting and receiving.

[0080] Optionally, the processing unit 502 may be a processing device. Some or all of the functions of the processing device may be implemented by software.

[0081] In an exemplary embodiment, some or all of the functions of the processing device are implemented using software. In this case, the processing device may include a memory and a processor. The memory is adapted to store a computer program. The processor reads and executes a computer program stored in the memory to perform the steps implemented by the terminal device in the satellite base station in the embodiments of the method.

[0082] Optionally, in an exemplary embodiment, the processing device includes a processor. A memory adapted to store a computer program located outside of a processing device. The processor is connected to the memory via a circuit/electrical wire for reading and executing a computer program stored in the memory.

[0083] In an exemplary embodiment, all functions of the processing device may be implemented using hardware. In this case, the processing device may include an input interface circuit, a logic circuit, and an output interface circuit. The input interface circuit is configured to receive ephemeris information of the first satellite base stations, wherein the first satellite base stations are satellite base stations that cover the terminal device. The logic circuitry is configured to: determine, based on the ephemeris information, the target satellite base station to which the terminal device needs to perform a handover; determine, based on the determined target satellite base station, the first time at which the terminal apparatus needs to perform a handover to the target satellite base station; and perform handover based on the determined first time to the target cell served by the target satellite base station.

[0084] Optionally, the output interface circuit outputs satellite base station ephemeris information to memory for storage.

[0085] In another embodiment, communication device 500 may be a chip. In this case, the transceiver unit 501 may specifically be a communication interface or a transceiver circuit.

[0086] Figure 6 shows a block diagram of a terminal device 600 according to the present application. As shown in FIG. 6, terminal device 600 includes a processor 601 and a transceiver 602.

[0087] Optionally, terminal device 600 further includes memory 603. Processor 601, transceiver 602, and memory 603 may communicate with each other via an internal communication path to transmit a control signal and/or a data signal.

[0088] The memory 603 is adapted to store a computer program. The processor 601 is configured to execute the computer program stored in the memory 603, thereby realizing the functions of the communication device 500 in the above device embodiment.

[0089] In particular, the processor 601 may be configured to perform the operation and/or processing performed by the processing unit 502 described in the embodiment of the apparatus shown in FIG. The transceiver 602 is configured to perform the operation and/or processing performed by the transceiver unit 501.

[0090] For example, the transceiver 602 receives the ephemeris information of the first satellite base stations, wherein the first satellite base stations are satellite base stations that cover the terminal apparatus. In another example, the processor 601 determines, based on the ephemeris information, the target satellite base station to which the terminal device needs to handover; determine, based on the determined target satellite base station, the first time at which the terminal apparatus needs to perform a handover to the target satellite base station; and perform handover based on the determined first time to the target cell served by the target satellite base station.

[0091] Optionally, memory 603 may be integrated with processor 601 or independent of processor 601.

[0092] Optionally, terminal device 600 may further include an antenna 604 configured to transmit a signal output by transceiver 602. Alternatively, transceiver 602 receives the signal via the antenna.

[0093] Optionally, terminal device 600 may further include a power source 605 configured to supply power to various components or circuits in the terminal device.

[0094] In addition, to make the functions of the terminal device more complete, the terminal device 600 may further include one or more of an input block 606, a display block 607 (which may also be considered an output block), an audio circuit 608, a camera 609, sensor 610, and the like. The audio circuitry may further include a speaker 6081, a microphone 6082, and the like. Details are not described here.

[0095] In addition, the present application further provides a communication system including satellite base stations and a terminal device in method embodiments.

[0096] The present application also provides a computer-readable storage medium. A computer-readable storage medium stores a computer program. When the computer program is executed by the computer, the steps and/or processing performed by the satellite base station in any of the aforementioned method embodiments are caused to be carried out by the computer.

[0097] The present application also provides a computer program product. The computer program product includes computer program code. When the computer program code is executed on the computer, the steps and/or processing performed by the satellite base station in any of the aforementioned method embodiments are caused to be carried out by the computer.

[0098] The present application further provides a chip. The microcircuit includes a processor. A memory adapted to store a computer program is located independently of the chip. The processor is configured to execute a computer program stored in the memory to perform the steps and/or processing performed by the satellite base station in any of the above method embodiments.

[0099] In addition, the chip may include a memory and a communication interface. The communication interface may be an input/output interface, a pin, an input/output circuit, or the like.

[00100] The present application also provides a computer-readable storage medium. A computer-readable storage medium stores a computer program. When the computer program is executed by the computer, the operations and/or processing performed by the terminal device in any of the aforementioned embodiments of the method are enabled to be performed by the computer.

[00101] The present application also provides a computer program product. The computer program product includes computer program code. When the computer program code is executed on the computer, the steps and/or processing performed by the terminal device in any of the aforementioned method embodiments are caused to be carried out by the computer.

[00102] The present application further provides a chip. The microcircuit includes a processor. A memory adapted to store a computer program is located independently of the chip. The processor is configured to execute a computer program stored in the memory to perform operations and/or processing performed by a terminal device in any of the above method embodiments.

[00103] In addition, the chip may include a memory and a communication interface. The communication interface may be an input/output interface, a pin, an input/output circuit, or the like.

[00104] FIG. 7 is a schematic block diagram of a network device 700 according to the present application. Network device 700 may correspond to a satellite base station in embodiments of the method. As shown in FIG. 7, the network device 700 includes an antenna 701, a radio frequency device 702, and a baseband device 703. The antenna 701 is connected to the RF device 702. In the uplink direction, the RF device 702 receives a signal from the terminal device via the antenna 701 and sends the received signal to the baseband device 703 for processing. In the downlink direction, the baseband device 703 generates a signal to be sent to the terminal device and sends the generated signal to the RF device 702. The RF device 702 transmits the signal through the antenna 701.

[00105] Baseband device 703 may include one or more processing units 7031. Block 7031 processing, in particular, may be a processor.

[00106] In addition, the baseband device 703 may further include one or more storage units 7032 and one or more communication interfaces 7033. The storage unit 7032 is configured to store a computer program and/or data. The communication interface 7033 is configured to communicate with the RF device 702. The storage unit 7032 may in particular be a memory. Communication interface 7033 may be an input/output interface or a transceiver circuit.

[00107] Optionally, the storage unit 7032 may be a storage unit located on the same chip as the processing unit 7031, i.e., an on-chip storage unit; or may be a storage unit located on a chip other than the processing unit 7031, that is, a storage unit off the chip. In the present application, this is not expressly limited.

[00108] In FIG. 7, the baseband device 703 may perform the operations and/processing performed by the processing unit 502 in the embodiment of the device shown in FIG. The RF device 702 may perform the operations and/processing performed by the transceiver unit 501 in the embodiment of the device shown in FIG.

[00109] In an embodiment, the processing unit 502 in the communication device 500 shown in FIG. 5 may be the baseband device 703 shown in FIG. 7, and the transceiver unit 501 may be an RF device 702.

[00110] The processor described in the previous embodiments may be an integrated circuit chip and may process signals. During implementation, the steps in the above method embodiments may be implemented using a hardware integrated logic circuit in a processor or via instructions in the form of software. The processor may be a general purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a Field Programmable Gate Array (FPGA), or other programmable logic device. , a discrete gate or transistorized logic device, or a discrete hardware component. A general purpose processor may be a microprocessor, or the processor may be any conventional processor or the like. The steps of the methods disclosed in the embodiments of the present application may be executed directly and executed using a hardware encoding processor, or may be executed and executed using a combination of hardware and software modules in an encoding processor. The software module may be located on a storage medium well known in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or a register. The storage medium is located in the memory and the processor reads the information in the memory and performs the steps of the above methods in conjunction with the processor hardware.

[00111] The memory mentioned in the above embodiments may be volatile (short-term) memory or non-volatile (long-term) memory, or may include volatile memory and non-volatile memory. Non-volatile memory can be read-only memory (ROM), programmable read-only memory (programmable ROM (PROM)), erasable programmable read-only memory (erasable PROM (EPROM)), electrically erasable programmable read-only memory (EPROM). electrically EPROM (EEPROM)) or flash memory. The volatile memory may be a random access memory (RAM) used as an external cache. By way of example, and not by way of limitation, many forms of RAM can be used, for example, static random access memory (static RAM (SRAM)), dynamic random access memory (dynamic RAM (DRAM)), synchronous dynamic random access memory access (synchronous DRAM (SDRAM)), synchronous dynamic random access memory with double data rate (double data rate SDRAM (DDR SDRAM)), improved synchronous dynamic random access memory (enhanced SDRAM (ESDRAM)), dynamic memory Synchlink DRAM (SLDRAM) random access device, and direct rambus RAM (DR RAM)). It should be noted that the memory of the systems and methods described herein includes, but is not limited to, these and any other appropriate type of memory.

[00112] One skilled in the art may be aware that, in combination with the examples described in the embodiments disclosed herein, the blocks and steps of an algorithm may be implemented by electronic hardware or a combination of computer software and electronic hardware. The performance of functions by hardware or software depends on the specific applications and the state of the design constraints of the technical solutions. A person skilled in the art can use various methods to implement the described functions for each particular application, but such an implementation should not be considered to be outside the scope of this application.

[00113] One skilled in the art can clearly understand that for the purposes of a convenient and concise description of the detailed working process of the aforementioned system, apparatus, and unit, reference should be made to the corresponding process in the aforementioned method embodiments, and details are omitted here again.

[00114] In several embodiments provided herein, it should be understood that the disclosed system, apparatus, and method may be implemented differently. For example, the device embodiment described is merely an example. For example, blocking is simply a division of logical functions, and may be another division in the actual implementation. For example, many blocks or components may be combined or integrated into another system, or some functionality may be ignored or not performed. In addition, the interconnections or direct links or communication connections shown or described may be implemented using certain interfaces. Indirect connections or communication connections between devices or units can be implemented electrically, mechanically, or take other forms.

[00115] Blocks described as separate parts may or may not be physically separate, and parts displayed as blocks may or may not be physical blocks, may be located in the same location, or may be distributed over multiple network blocks. Some or all of the blocks may be selected based on actual requirements in order to achieve the objectives of the decisions in the mentioned embodiments.

[00116] In addition, the functional blocks in the embodiments of the present application may be integrated into one processing unit, or each of the units may exist separately physically, or two or more units are integrated into one unit.

[00117] When the functions are implemented in the form of a software functional block and sold or used as a standalone product, the functions may be stored on a computer-readable storage medium. Based on this understanding, the technical solutions of the present application per se, or part contributing to the current technology, or some of the technical solutions can be implemented in the form of a software product. The software product is stored on a storage medium and includes several instructions for directing a computing device (personal computer, server, or network device) to perform all or some of the steps of the methods described in embodiments of the present application. The above storage media includes: any media that can store program code, such as a USB flash drive, removable hard disk, read-only memory (ROM), random access memory (RAM) ), magnetic disk or optical disk.

[00118] The above description is only specific implementations of this application, but is not intended to limit the scope of protection of this application. Any change or replacement readily detectable by a person skilled in the art within the technical scope disclosed in this application should fall within the scope of this application. Therefore, the scope of protection of the present application should be determined by the scope of protection of the claims.

TRANSLATION OF DRAWINGS

Fig.1

Satellite 1 - Satellite 1

Satellite 2 - Satellite 2

Satellite 3 - Satellite 3

Time 1 - Time 1

Time 2 - Time 2

Time 3 - Time 3

Fig.2

Satellite base station - Satellite base station

NG interface - NG interface

Terrestrial station - Terrestrial station

5G core network - 5G core network

Data network - Data network

Xn interface - Xn interface

Fig.3

Terminal device - Terminal device

Ephemeris information network element - Network element of ephemeris information

Serving cell - Serving cell

Destination cell - Destination cell

301 - Sending a request for ephemeris information

302 - Sending signaling, moreover, the signaling includes the ephemeris information of the first satellite base stations

303 - Determining, based on ephemeris information, the target satellite base station to which the terminal device needs to handover

304 - Determining, based on the determined target satellite base station, the first time at which the terminal apparatus needs to handover to the target satellite base station

305 - The terminal device performs handover based on the determined first time to the target cell included in the target satellite base station

Fig.4

Satellite base station - Satellite base station

Serving cell - Serving cell

Destination cell - Destination cell

401 - Receiving a broadcast message

402 - Determining, based on ephemeris information, the final satellite base station to which the terminal device needs to handover

403 - Determining, based on the determined target satellite base station, the first time at which the terminal apparatus needs to perform handover to the target satellite base station

404 - The terminal device performs handover based on the determined first time to the target cell included in the target satellite base station

Fig.5

500 - Communication device

501 - Transceiver unit

502 - Processing unit

Fig.6

601 - Processor

602 - Transceiver

603 - Memory

605 - Power supply

606 - Input block

607 - Display unit

608 - Sound scheme

6081 - Loudspeaker

6082 - Microphone

609 - Camera

610 - Sensor

Fig.7

702 - RF device

703 - Base Band Device

7031 - Processing unit

7032 - Storage block

7033 - Communication interface.

Claims (34)

1. A handover method in satellite communications, comprising the steps of: receive by means of the terminal device ephemeris information of the first satellite base stations, wherein the first satellite base stations are satellite base stations that cover the terminal device, wherein the ephemeris information includes the angle of inclination of the satellite orbital plane, the right ascension of the ascending node, the major semi-axis of the orbital ellipse , the eccentricity of the orbital ellipse, the angular distance of perigee, the moment at which the satellite passes perigee; determining, by the terminal device, based on the ephemeris information, the target satellite base station to which the terminal device needs to perform a handover; determining, by the terminal device, based on the determined target satellite base station, the first time at which the terminal device needs to perform a handover to the target satellite base station; And handover is performed by the terminal device on the basis of said determined first time to the target cell served by the target satellite base station. 2. The method according to claim 1, wherein the receipt by the terminal device of the ephemeris information of the first satellite base stations comprises the steps of: sending, by the terminal device, an ephemeris information request to the ephemeris information network element, the ephemeris information request containing location information of the terminal device; And receiving, by means of the terminal device, a signaling sent by the network element of the ephemeris information, the signaling comprising the ephemeris information of the first satellite base stations. 3. The method of claim 2, wherein the terminal device determines, based on the ephemeris information, the target satellite base station to which the terminal device needs to handover, comprising the steps of: calculating, by the terminal device, a second time based on the ephemeris information, the second time being the initial coverage time of the terminal device by satellite base stations covering the terminal device; determining, by the terminal device, second satellite base stations based on the second time, wherein the second satellite base stations are satellite base stations to cover the terminal device after the current moment; And calculating, by the terminal device, distances between the second satellite base stations and the terminal device based on the ephemeris information of the second satellite base stations and the location information of the terminal device, and determining the nearest satellite base station of the second satellite base stations as the target satellite base station. 4. The method of claim 3, wherein the terminal device determines, based on the determined target satellite base station, the first time at which the terminal device needs to handover to the target satellite base station, comprising the step of calculating, by the terminal device, the movement speed of the target satellite base station. base station based on the ephemeris information of the target satellite base station, and the first time is calculated based on the moving speed of the target satellite base station, the moving speed of the terminal apparatus, and the predetermined handover advance. 5. The method according to claim 1, wherein the receipt by the terminal device of the ephemeris information of the first satellite base stations comprises receiving a broadcast message by the terminal device, wherein the broadcast message contains at least one of the following parameters: identification information of the first satellite base stations and identification information, coverage times, and longitude and latitude information, which are related to cells contained in the first satellite base stations, and for cell coverage times contained in the first satellite base stations, cover the locations represented by the longitude and latitude information. 6. The method according to claim 5, wherein the terminal device determines, based on the ephemeris information, the target satellite base station to which the terminal device needs to handover, comprising the steps of: determine by the terminal apparatus, based on the identification information of the first satellite base stations and the identification information, coverage times, and longitude and latitude information that relate to the cells contained in the first satellite base stations, a cell that relates to the cells contained in the first satellite base stations , and which first covers the terminal device; And determining, as the end satellite base station, the base station to which the cell that first covers the terminal device belongs. 7. The method of claim 6, wherein the terminal device determines, based on the determined target satellite base station, the first time at which the terminal device needs to handover to the target satellite base station, comprising the step of calculating, by the terminal device, the first time based on the coverage time of the target satellite base station and the given handover advance. 8. The method according to any one of claims 5 to 7, wherein the broadcast message is sent to one of the first satellite base stations or the broadcast message is sent to each of the first satellite base stations. 9. A handover device in satellite communications, comprising: a transceiver unit configured to receive ephemeris information of the first satellite base stations, wherein the first satellite base stations are satellite base stations that cover the terminal apparatus, wherein the ephemeris information includes the angle of inclination of the satellite orbital plane, right ascension of the ascending node, greater semiaxis of the orbital ellipse, eccentricity of the orbital ellipse, angular distance of perigee, moment at which the satellite passes perigee; And a processing unit, configured to: determine, based on the ephemeris information, the target satellite base station to which the terminal apparatus needs to perform a handover; to determine, based on this determined target satellite base station, the first time at which the terminal apparatus needs to perform a handover to the target satellite base station; and perform a handover based on said determined first time to the target cell served by the target satellite base station. 10. The apparatus of claim 9, wherein the transceiver unit is specifically configured to: send a request for ephemeris information to an ephemeris information network element, wherein the request for ephemeris information contains location information of the terminal device; and receiving the signaling sent by the network element of the ephemeris information, the signaling comprising the ephemeris information of the first satellite base stations. 11. The apparatus of claim 10, wherein the processing unit is specifically configured to: calculate a second time based on the ephemeris information, the second time being the start time of coverage of the terminal device by satellite base stations covering the terminal device; determine the second satellite base stations based on the second time, while the second satellite base stations are satellite base stations that should cover the terminal device after the current moment; and calculate distances between the second satellite base stations and the terminal device based on the ephemeris information of the second satellite base stations and the location information of the terminal device, and determine the nearest satellite base station of the second satellite base stations as the target satellite base station. 12. The apparatus of claim 11, wherein the processing unit is specifically configured to calculate the movement speed of the destination satellite base station based on the ephemeris information of the destination satellite base station, and calculate the first time based on the movement speed of the destination satellite base station, the movement speed of the terminal device, and the predetermined handover advance. 13. The apparatus of claim 9, wherein the transceiver unit is specifically configured to receive a broadcast message, wherein the broadcast message comprises at least one of the following: first satellite base station identification information and identification information, coverage times and longitude information, and latitude, which refer to the cells contained in the first satellite base stations, and over the coverage times of the cells contained in the first satellite base stations, cover the locations represented by the longitude and latitude information. 14. The apparatus of claim 13, wherein the processing unit is specifically configured to: determine, by the terminal device, based on the identification information of the first satellite base stations and the identification information, coverage times, and longitude and latitude information that are related to the cells contained in the first satellite base stations, a cell which refers to the cells contained in the first satellite base stations and which first covers the terminal apparatus; and determine, as the target satellite base station, the base station to which the cell that first covers the terminal apparatus belongs. 15. The apparatus of claim 14, wherein the processing unit is specifically configured to calculate the first time based on the coverage time of the destination satellite base station and the predetermined handover advance. 16. An apparatus according to any one of claims 13-15, wherein the broadcast message is sent to one of the first satellite base stations, or the broadcast message is sent to each of the first satellite base stations. 17. Communication device, comprising: one or more processors; And memory adapted to store one or more programs, while when one or more programs are executed by one or more processors, the implementation by one or more processors of the method according to any one of claims 1-8 is provided. 18. A computer-readable storage medium containing a computer program, wherein, when the computer program is executed on the computer, the computer executes the method according to any one of claims 1-8.

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