CN114614874A

CN114614874A - Satellite switching method and device

Info

Publication number: CN114614874A
Application number: CN202011329778.9A
Authority: CN
Inventors: 商鹏程; 施南翔; 张剑寅; 刘景磊
Original assignee: China Mobile Communications Group Co Ltd; China Mobile Communications Ltd Research Institute
Current assignee: China Mobile Communications Group Co Ltd; China Mobile Communications Ltd Research Institute
Priority date: 2020-11-24
Filing date: 2020-11-24
Publication date: 2022-06-10

Abstract

The invention provides a satellite switching method and equipment, belonging to the technical field of communication, wherein the satellite switching method applied to a core network comprises the following steps: determining a second satellite to be accessed or resided next by the terminal according to the current position information of the terminal and an ephemeris; and sending first notification information to a first satellite currently accessed or resided by the terminal and/or the terminal, wherein the first notification information is used for indicating that the terminal is to be accessed or resided in the second satellite. According to the invention, the core network actively pre-judges the next satellite to be accessed or resident by the terminal, and the terminal is not required to carry out signal measurement, so that the interactive resource overhead between the terminal and the satellite is effectively reduced, the energy consumption of the terminal is reduced, and the accuracy and the real-time performance of satellite access are improved.

Description

Satellite switching method and device

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a satellite switching method and device.

Background

The purpose of mobility management is to provide mobility for terminals and services, so that the user can reach the best state in connection with the network, which mainly includes two aspects of location management and handover management.

At present, in related technologies, mobility location update is mainly due to location change of a mobile terminal itself, or periodic location update configured by a network, and a request for triggering location update to a network side is initiated by detecting surrounding wireless signal strength or performing neighbor measurement by the mobile terminal.

In the current ground network and satellite network, the mobility management principle and flow of the mobile network are used, and in most cases, the mobile terminal is responsible for initiating a request for location update. The terminal needs to establish connection with a plurality of satellites simultaneously, determines a switching target satellite and a switching time point by measuring signal strength, and switches frequently. Thus, the signaling overhead between the terminal and the satellite and between the satellite and the core network is large; meanwhile, the terminal has limited measurement capability on the satellite, and the situation that an accurate measurement result cannot be provided is easily caused, so that the switching failure probability is high.

Disclosure of Invention

In view of this, the present invention provides a satellite switching method and device, which are used to solve the problems of high signaling overhead and high switching failure rate of the current satellite switching scheme.

In order to solve the above technical problem, in a first aspect, the present invention provides a satellite handover method, applied to a core network, including:

determining a second satellite to be accessed or resided next by the terminal according to the current position information of the terminal and an ephemeris;

and sending first notification information to a first satellite currently accessed or resided by the terminal and/or the terminal, wherein the first notification information is used for indicating that the terminal is to be accessed or resided in the second satellite.

Optionally, the first satellite and the second satellite are non-geosynchronous orbit satellites.

Optionally, after the sending the first notification information to the first satellite currently accessed or camped on by the terminal and/or the terminal, the method further includes:

under the condition that the area to which the position of the terminal belongs is determined not to be changed, sending second notification information; the second notification information includes at least one of:

third notification information used for sending to the first satellite, wherein the third notification information is used for instructing the first satellite to start the handover of the terminal to the second satellite;

fourth notification information for sending to the second satellite, the fourth notification information being used to instruct the second satellite to establish a resource link with the terminal;

fifth notification information for sending to the first satellite, the fifth notification information being used to instruct the first satellite to release the resources allocated to the terminal.

Optionally, the sending the second notification information includes:

determining the moment of satellite switching or redirection;

and sending the second notification information at the first moment according to the moment of switching or redirecting the satellite.

receiving the position information reported by the terminal;

and determining that the region to which the position of the terminal belongs is not changed according to the position information.

Optionally, the first notification information sent to the first satellite is further used to indicate that, after a preset time period elapses, if it is determined that the area to which the location of the terminal belongs does not change, the resource allocated to the terminal is released.

Optionally, before sending the second notification information, the method further includes:

sending request information to the second satellite, wherein the request information is used for requesting the relevant information of the second satellite, and the relevant information of the second satellite comprises at least one of identification, a running track and a service area;

receiving the relevant information of the second satellite sent by the second satellite according to the request information;

and determining the real legality of the second satellite according to the related information of the second satellite and the ephemeris.

measuring the orbit and/or elevation angle of the second satellite;

and determining the true validity of the second satellite according to the measured orbit and/or the elevation angle of the second satellite and the ephemeris.

Optionally, the determining, according to the current location information of the terminal and the ephemeris, before the second satellite to be accessed or resided by the terminal next, further includes:

receiving an authentication request sent by the terminal through the first satellite, wherein the authentication request comprises an identifier of the terminal and a first identifier, and the first identifier is the identifier of the first satellite;

measuring the orbit and/or elevation of the first satellite;

determining the true validity of the first satellite according to the measured orbit and/or elevation angle of the first satellite and the ephemeris;

and authenticating the terminal.

Optionally, after receiving the authentication request sent by the terminal through the first satellite, the method further includes:

and starting to pre-judge the real legality of other satellites of the constellation system where the first satellite is located, wherein the other satellites comprise the second satellite.

In a second aspect, the present invention further provides a satellite switching method, applied to a terminal, including:

receiving first notification information sent by a core network, wherein the first notification information is used for indicating that the terminal is to access or reside in a second satellite, and the second satellite which the terminal is to access or reside in is determined by the core network according to current position information of the terminal and an ephemeris.

Optionally, the second satellite is a non-geosynchronous orbit satellite.

Optionally, after receiving the first notification information sent by the core network, the method further includes:

and reporting the position information to the core network so that the core network determines whether the area to which the position of the terminal belongs changes or not according to the position information of the terminal.

In a third aspect, the present invention further provides a satellite switching method, applied to a first satellite, including:

receiving first notification information sent by a core network, wherein the first notification information is used for indicating that a terminal which is currently accessed to or resided in a first satellite is to be accessed to or resided in a second satellite, and the second satellite which is accessed to or resided in the terminal is determined by the core network according to the current position information of the terminal and an ephemeris.

Optionally, before receiving the first notification information sent by the core network, the method further includes:

receiving an authentication request sent by the terminal, wherein the authentication request comprises an identifier of the terminal;

adding a first identifier in the authentication request, wherein the first identifier is the identifier of the first satellite;

and sending the authentication request to the core network.

receiving second notification information sent by the core network, where the second notification information includes third notification information and/or fifth notification information, the third notification information is used to instruct the first satellite to start the handover from the terminal to the second satellite, and the fifth notification information is used to instruct the first satellite to release resources allocated to the terminal.

after a preset time period, determining whether the region to which the position of the terminal belongs changes;

and if the area to which the position of the terminal belongs is not changed, releasing the resources allocated to the terminal.

In a fourth aspect, the present invention further provides a core network, including:

the prediction module is used for determining a second satellite to be accessed or resided next by the terminal according to the current position information of the terminal and an ephemeris;

the first notification module is configured to send first notification information to a first satellite currently accessed to or camped on by the terminal and/or the terminal, where the first notification information is used to indicate that the terminal is to access to or camp on the second satellite.

Optionally, the core network further includes:

the second notification module is used for sending second notification information under the condition that the area to which the position of the terminal belongs is determined not to change; the second notification information includes at least one of:

Optionally, the second notification module includes:

the time determining unit is used for determining the switching or redirection time of the satellite;

and the sending unit is used for sending the second notification information at the first moment according to the satellite switching or redirection moment.

Optionally, the core network further includes:

the position information receiving module is used for receiving the position information reported by the terminal;

and the judging module is used for determining that the region to which the position of the terminal belongs does not change according to the position information.

Optionally, the core network further includes:

a request module, configured to send request information to the second satellite, where the request information is used to request information related to the second satellite, and the information related to the second satellite includes at least one of an identifier, a running track, and a service area;

the information receiving module is used for receiving the relevant information of the second satellite sent by the second satellite according to the request information;

and the first authentication module is used for determining the real legality of the second satellite according to the related information of the second satellite and the ephemeris.

Optionally, the core network further includes:

a first measurement module for measuring the orbit and/or elevation of the second satellite;

and the second authentication module is used for determining the real legality of the second satellite according to the measured orbit and/or the elevation angle of the second satellite and the ephemeris.

Optionally, the core network further includes:

a first authentication request receiving module, configured to receive an authentication request sent by the terminal through the first satellite, where the authentication request includes an identifier of the terminal and a first identifier, and the first identifier is an identifier of the first satellite;

the second measurement module is used for measuring the operation orbit and/or the elevation angle of the first satellite;

a third authentication module, configured to determine the validity of the first satellite according to the measured orbit and/or elevation angle of the first satellite and the ephemeris;

and the terminal authentication module is used for authenticating the terminal.

Optionally, the core network further includes:

and the pre-judging module is used for starting the pre-judgment of the real legality of other satellites of the constellation system where the first satellite is located, wherein the other satellites comprise the second satellite.

In a fifth aspect, the present invention further provides a terminal, including:

the first notification receiving module is configured to receive first notification information sent by a core network, where the first notification information is used to indicate that the terminal is to access or camp on a second satellite, and the second satellite that the terminal is to access or camp on is determined by the core network according to current location information of the terminal and an ephemeris.

Optionally, the second satellite is a non-geosynchronous orbit satellite.

Optionally, the terminal further includes:

and the position information reporting module is used for reporting the position information to the core network so that the core network determines whether the area to which the position of the terminal belongs changes or not according to the position information of the terminal.

In a sixth aspect, the present invention further provides a first satellite, comprising:

the first notification information receiving module is configured to receive first notification information sent by a core network, where the first notification information is used to indicate that a terminal currently accessing or residing in a first satellite will access or reside in a second satellite, and the second satellite to which the terminal will access or reside is determined by the core network according to current location information of the terminal and an ephemeris.

Optionally, the first satellite further includes:

a second authentication request receiving module, configured to receive an authentication request sent by the terminal, where the authentication request includes an identifier of the terminal;

an identifier adding module, configured to add a first identifier to the authentication request, where the first identifier is an identifier of the first satellite;

and the authentication request sending module is used for sending the authentication request to the core network.

Optionally, the first satellite further includes:

a second notification information receiving module, configured to receive second notification information sent by the core network, where the second notification information includes third notification information and/or fifth notification information, the third notification information is used to instruct the first satellite to start handover from the terminal to the second satellite, and the fifth notification information is used to instruct the first satellite to release resources allocated to the terminal.

Optionally, the first satellite further includes:

the terminal position determining module is used for determining whether the region to which the position of the terminal belongs changes after a preset time period;

and the resource release module is used for releasing the resources allocated to the terminal if the area to which the position of the terminal belongs is not changed.

In a seventh aspect, the present invention further provides a core network, including: a transceiver and a processor;

the processor is used for determining a second satellite to be accessed or resided next by the terminal according to the current position information of the terminal and an ephemeris;

the transceiver is configured to send first notification information to a first satellite currently accessed or camped on by the terminal and/or the terminal, where the first notification information is used to indicate that the terminal is to access or camp on the second satellite.

Optionally, the transceiver is further configured to send second notification information when it is determined that an area to which the location of the terminal belongs is not changed; the second notification information includes at least one of:

Optionally, the processor is configured to determine a time for satellite handover or redirection;

and the transceiver is used for sending the second notification information at a first moment according to the moment of switching or redirecting the satellite.

Optionally, the transceiver is further configured to receive location information reported by the terminal;

the processor is further configured to determine, according to the location information, that the area to which the location of the terminal belongs does not change.

Optionally, the first notification information sent to the first satellite is further used to indicate that, after a preset time period has elapsed, if it is determined that the area to which the location of the terminal belongs does not change, the resource allocated to the terminal is released.

Optionally, the transceiver is further configured to send request information to the second satellite, where the request information is used to request information related to the second satellite, and the information related to the second satellite includes at least one of an identifier, a trajectory, and a service area;

the transceiver is further used for receiving the relevant information of the second satellite sent by the second satellite according to the request information;

the processor is further configured to determine a true validity of the second satellite according to the relevant information of the second satellite and the ephemeris.

Optionally, the transceiver is further configured to measure an orbit and/or an elevation angle of the second satellite;

the processor is further configured to determine the authenticity of the second satellite based on the measured orbit and/or elevation angle of the second satellite and the ephemeris.

Optionally, the transceiver is further configured to receive an authentication request sent by the terminal through the first satellite, where the authentication request includes an identifier of the terminal and a first identifier, and the first identifier is an identifier of the first satellite;

the transceiver is also used for measuring the operation orbit and/or the elevation angle of the first satellite;

the processor is further configured to determine the validity of the first satellite in real life based on the measured orbit and/or elevation angle of the first satellite and the ephemeris;

the processor is further configured to authenticate the terminal.

Optionally, the processor is further configured to start pre-determination of the real legitimacy of other satellites of the galaxy where the first satellite is located, where the other satellites include the second satellite.

In an eighth aspect, the present invention further provides a terminal, including: a transceiver and a processor;

the transceiver is configured to receive first notification information sent by a core network, where the first notification information is used to indicate that the terminal is to access or camp on a second satellite, and the second satellite that the terminal is to access or camp on is determined by the core network according to current location information of the terminal and an ephemeris.

Optionally, the second satellite is a non-geosynchronous orbit satellite.

Optionally, the transceiver is further configured to report location information to the core network, so that the core network determines whether the area to which the location of the terminal belongs changes according to the location information of the terminal.

In a ninth aspect, the present invention also provides a first satellite, comprising: a transceiver and a processor;

the transceiver is configured to receive first notification information sent by a core network, where the first notification information is used to indicate that a terminal currently accessing or residing in a first satellite will access or reside in a second satellite, and the second satellite to which the terminal will access or reside is determined by the core network according to current location information of the terminal and ephemeris.

Optionally, the transceiver is further configured to receive an authentication request sent by the terminal, where the authentication request includes an identifier of the terminal;

the processor is configured to add a first identifier to the authentication request, where the first identifier is an identifier of the first satellite;

the transceiver is further configured to send the authentication request to the core network.

Optionally, the transceiver is further configured to receive second notification information sent by the core network, where the second notification information includes third notification information and/or fifth notification information, the third notification information is used to instruct the first satellite to start the handover from the terminal to the second satellite, and the fifth notification information is used to instruct the first satellite to release resources allocated to the terminal.

Optionally, the processor is configured to determine whether a region to which the position of the terminal belongs changes after a preset time period elapses;

the processor is further configured to release the resource allocated to the terminal if the area to which the location of the terminal belongs does not change.

In a tenth aspect, the present invention further provides a core network, including a memory, a processor, and a program stored in the memory and executable on the processor; the processor implements any of the above steps in the satellite handover method applied to the core network when executing the program.

In an eleventh aspect, the present invention further provides a terminal, including a memory, a processor, and a program stored on the memory and executable on the processor; the processor implements any of the steps applied to the terminal satellite switching method when executing the program.

In a twelfth aspect, the present invention further provides a first satellite, including a memory, a processor, and a program stored on the memory and executable on the processor; the processor implements any of the above steps in a satellite switching method applied to the first satellite when executing the program.

In a ninth aspect, the present invention further provides a readable storage medium, on which a program is stored, which when executed by a processor implements the steps in any of the above-mentioned satellite switching methods.

The technical scheme of the invention has the following beneficial effects:

in the embodiment of the invention, the core network actively pre-judges the satellite to be accessed or resided next by the terminal without the terminal for signal measurement, thereby effectively reducing the interactive resource overhead between the terminal and the satellite, reducing the energy consumption of the terminal and improving the accuracy and the real-time property of satellite access.

Drawings

Fig. 1 is a schematic flowchart of a satellite handover method applied to a core network according to a first embodiment of the present invention;

fig. 2 is a schematic flowchart of a dual-id based terminal and satellite authentication according to an embodiment of the present invention;

fig. 3 is a flowchart illustrating a satellite handover method applied to a terminal according to a second embodiment of the present invention;

fig. 4 is a flowchart illustrating a satellite switching method applied to a first satellite according to a third embodiment of the present invention;

fig. 5 is a flowchart illustrating a satellite switching method applied to a second satellite according to a fourth embodiment of the present invention;

fig. 6 is a flowchart illustrating a terminal connection state mobility management according to an embodiment of the present invention;

fig. 7 is a flowchart illustrating idle mobility management of a terminal according to an embodiment of the present invention;

fig. 8 is a schematic structural diagram of a core network in a fifth embodiment of the present invention;

fig. 9 is a schematic structural diagram of a terminal according to a sixth embodiment of the present invention;

fig. 10 is a schematic structural diagram of a first satellite according to a seventh embodiment of the present invention;

fig. 11 is a schematic structural diagram of a core network in an eighth embodiment of the present invention;

fig. 12 is a schematic structural diagram of a terminal according to a ninth embodiment of the present invention;

fig. 13 is a schematic structural diagram of a first satellite according to a tenth embodiment of the present invention;

fig. 14 is a schematic structural diagram of a core network in an eleventh embodiment of the present invention;

fig. 15 is a schematic structural diagram of a terminal according to a twelfth embodiment of the present invention;

fig. 16 is a schematic structural diagram of a first satellite according to a thirteenth embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the description of the embodiments of the invention given above, are within the scope of protection of the invention.

Referring to fig. 1, fig. 1 is a schematic flowchart of a satellite handover method according to an embodiment of the present invention, where the method is applied to a core network (specifically, a core network device), and includes the following steps:

step 11: the core network determines a second satellite to be accessed or resided next by the terminal according to the current position information of the terminal and an ephemeris;

mobility location management is divided into the following two cases from the state of the terminal:

based on a continuous coverage network, when a terminal (User Equipment, UE, which may also be referred to as User Equipment, User, terminal Equipment, mobile terminal, etc.) moves to a cell edge, the quality of a cell service signal deteriorates, the quality of a cell signal in an adjacent cell increases, and the terminal determines to trigger a handover through signal measurement, which mainly includes several links of triggering, measuring, deciding, and switching;

and (3) idle mobility management, wherein the mobile terminal searches a cell to obtain a cell identifier and other information, and the redirection to a target area is completed in a redirection (redirect) mode.

It should be noted that, if the terminal is in an IDLE state (RRC _ IDLE), the core network determines that it is the second satellite where the terminal will reside next; if the terminal is in the CONNECTED state (RRC _ CONNECTED), the core network determines that the terminal will access the second satellite next.

The ephemeris includes a running track and a running period of each satellite, and the satellites in the ephemeris may include all the satellites in the core network service area, where each satellite covers at least a part of the core network service area for a certain period of time.

In other alternative embodiments, the core network may also determine a satellite to be accessed next by the terminal according to the satellite to which the terminal currently accesses, or determine a satellite to be camped next by the terminal according to the satellite in which the terminal currently resides.

Step 12: and the core network sends first notification information to a first satellite which the terminal currently accesses or resides in and/or the terminal, wherein the first notification information is used for indicating that the terminal accesses or resides in the second satellite. That is, the core network may transmit the first notification information only to the first satellite, may transmit the first notification information only to the terminal, may transmit the first notification information to the first satellite and the terminal at the same time, and of course, the first notification information transmitted to the first satellite and the first notification information transmitted to the terminal may be the same or different.

It should be noted that, if a terminal only resides in a certain satellite and does not access the satellite, the terminal is in an idle state; if a terminal accesses a satellite, the terminal is in a connected state.

The embodiment of the invention can be applied to the situation that the terminal does not move in position (specifically, the area to which the terminal position belongs does not change) and only the satellite is switched. For example, when communication is performed using a Non-geostationary Orbit (NGSO) satellite, a situation in which a mobile terminal is not updated in position but the satellite is changed constantly occurs. If the traditional mobile network mobility management method and flow are used, the access is changed from the core network side and the terminal side, and the terminal triggers the location updating flow. Due to the short operation period of the NGSO satellite, in a typical scenario, the terminal needs to switch to the low-orbit satellite every 10 minutes. In the prior art, a terminal needs to establish connection with multiple satellites simultaneously, determines a switching target satellite and a switching time point by measuring signal strength, and switches frequently. Therefore, the signaling overhead between the terminal and the satellite and between the satellite and the core network is relatively large, but the NGSO satellite and the satellite terminal have very limited communication resources, very small bandwidth, relatively large time delay and relatively high packet loss rate, so that the signaling overhead of the existing mobility management method is difficult to bear, and the signaling overhead of the mobility management is increased due to the characteristic that the NGSO satellite has a small moving period interval. In addition, the terminal needs to establish connection with multiple satellites at the same time, and performs switching operation by measuring signal strength, but the terminal has limited measurement capability on the satellites, has low measurement accuracy, cannot provide accurate measurement results, and has high switching failure probability. Therefore, the embodiment of the invention provides that the core network actively judges the target satellite to be switched or redirected according to the configured ephemeris, which not only is accurate and timely, but also can reduce the signaling overhead of the terminal and the satellite.

The satellite switching method is exemplified below.

Optionally, the first satellite and the second satellite are non-geosynchronous orbit satellites, or are non-geostationary orbit satellites.

Optionally, after the sending the first notification information to the first satellite currently accessed to or camped on by the terminal and the terminal, the method further includes:

fourth notification information used for sending to the second satellite, where the fourth notification information is used to instruct the second satellite to establish a resource link with the terminal, that is, the fourth notification information is used to instruct the second satellite to allocate resources to the terminal so as to establish a link;

The satellite switching method provided by the embodiment of the invention can be suitable for scenes with unchanged terminal positions. The unchanged terminal position does not mean that the absolute position of the terminal is not changed, but means that the Area to which the terminal position belongs is not changed, for example, the location Area to which the terminal belongs is not changed or the position of the Tracking Area (TA) to which the terminal belongs is not changed.

The core network is an enhanced capability core network, has the functions of configuration and storage of an ephemeris, and can realize the process that a prejudgment terminal accesses (or resides in) a satellite and actively triggers the switching of the accessed satellite (or the redirection of the resident satellite).

In other optional embodiments, after the core network determines the second satellite to be accessed or resided next by the terminal, the core network may not trigger the handover procedure or redirection procedure, and the satellite currently accessed or resided by the terminal may start the handover procedure or redirection procedure. The specific process can be referred to as the process after the handover target satellite or the redirection target satellite has been determined in the related art.

Optionally, the sending the second notification information includes:

determining the moment of satellite switching or redirection;

and sending the second notification information at the first moment according to the satellite switching or redirecting moment.

In the embodiment of the present invention, the first notification message is to notify the first satellite and the terminal in advance that the terminal will possibly access (or camp on) the second satellite. Then, the core network may determine a specific time for switching (or redirecting), and after determining the specific time for switching (or redirecting), send the second notification information at a suitable time before actually starting switching (or redirecting) or when actually starting switching (or redirecting).

Specifically, the core network may determine the time when the terminal is switched or redirected to the second satellite according to ephemeris, or the core network may determine the time when the terminal is switched to the second satellite or redirected to the second satellite according to ephemeris and the orbit and/or elevation angle of the second satellite measured by the core network.

receiving the position information reported by the terminal;

In the embodiment of the present invention, the location information reported by the terminal may be the location information reported by the terminal triggered by the first notification information after the terminal receives the first notification information.

Of course, the location information reported by the terminal may also be the location information reported by the terminal after receiving the first notification information in the process of reporting the location information according to the preset period.

In another optional specific embodiment, the first notification information sent to the first satellite is further used to indicate that, after a preset time period has elapsed, if it is determined that the area to which the location of the terminal belongs does not change, the resource allocated to the terminal is released.

That is to say, in the embodiment of the present invention, the core network may not send the fifth notification information to the first satellite, but indicate, in the first notification information, that the first satellite has passed a period of time, and if it is determined that the area to which the location of the terminal belongs does not change, release the resource allocated to the terminal.

In the embodiment of the invention, the core network can determine the real legality of the second satellite according to the related information of the second satellite requested by the second satellite.

measuring the orbit and/or elevation angle of the second satellite;

In the embodiment of the invention, the core network can also determine the real legality of the second satellite according to the relevant information of the second satellite actually measured by the core network.

In the embodiment of the invention, the core network judges the access time and the real legality of the satellite to be switched by the configured ephemeris and the active measurement of the orbit and/or the elevation angle of the satellite under the condition that the terminal has no position change and only the satellite changes.

Furthermore, in the embodiment of the present invention, the core network may further determine the authenticity and validity of the second satellite by combining the relevant information of the second satellite sent by the second satellite, the relevant information of the second satellite measured by the core network itself, and the relevant information of the second satellite in the ephemeris, and perform multiple authentication verifications, so that the reliability is high.

measuring the orbit and/or elevation of the first satellite;

determining the true validity of the first satellite based on the measured orbit and/or elevation of the first satellite and the ephemeris;

and authenticating the terminal.

In the embodiment of the invention, when the terminal accesses the first satellite, or when the terminal accesses the core network through the first satellite, the core network needs to authenticate the terminal and the first satellite.

Specifically, in the embodiment of the present invention, a precondition based on mobility management is that both the terminal and the access satellite are legal, so a dual-identifier authentication method is proposed, and when the terminal accesses the core network through the satellite, the authentication process needs to be completed by using a dual-identifier (i.e., an external mobile identifier (an identifier of the satellite) + an internal fixed identifier (an identifier of the terminal)).

Further optionally, after receiving the authentication request sent by the terminal through the first satellite, the method further includes:

In the embodiment of the invention, when the core network carries out the legality authentication on the accessed terminal and the first satellite, the core network also carries out the legality judgment on other satellites of the galaxy where the first satellite is located. Specifically, the core network may perform the real validity pre-determination on the other satellites of the galaxy where the first satellite is located after completing the real validity authentication on the first satellite.

The first satellite and other satellites of the same galaxy are in the ephemeris, and the satellites of the same galaxy cover the area where the terminal is located at different moments.

The service area of a core network can be provided with a plurality of galaxies, satellites in the same galaxies cover a certain part of the service area of the core network at different times, and when a terminal accesses a certain satellite in a certain galaxies for the first time, other satellites in the galaxies are activated.

The authentication method based on dual identification in mobility management is illustrated in the following with reference to fig. 2.

Step 1: when a terminal accesses a core network through a satellite for the first time, a legality judgment process needs to be completed, an authentication request is sent to the core network, and the terminal needs to carry an identifier of the terminal, namely an internal fixed identifier, or an internal identifier and a second-layer identifier; wherein the authentication request may be carried in the registration request;

step 2: when the satellite forwards the registration request to the core network, a satellite identifier, namely an external mobile identifier, or an external identifier and a first-layer identifier, needs to be added on the basis of the terminal identifier, and is used for judging the validity of the core network for the satellite;

and step 3: the core network judges the real legality of the accessed satellite at the moment through capability enhancement, configuration of ephemeris information and automatic detection of the orbit and the elevation angle of the accessed satellite; and simultaneously starting to pre-judge the legality of other satellites of the constellation (or called constellation) where the satellite is located;

and 4, step 4: the core network issues an access satellite authentication result notice;

and 5: the core network strips the identification of the first layer of satellite to complete the authentication of the network to the terminal;

step 6: and the core network issues a terminal authentication result notice and the subsequent registration process is continued.

In the embodiment of the invention, the authentication process of the core network to the access satellite is added in the authentication process, the core network firstly authenticates the access satellite through the external identifier, and authenticates the mobile terminal through the internal identifier after the external identifier is stripped (the core network authenticates the satellite), thereby completing the legality authentication of the mobile terminal and the access satellite according to the double identifiers. The safety authentication process based on the double identifiers solves the problem of authentication of the core network to the terminal and the satellite, and improves the safety of communication.

In addition, after the satellite which is accessed to the terminal for the first time passes the authentication, the security judgment of other satellites of the satellite isosystem is started.

In the embodiment of the invention, the absolute geographic position of the terminal and the core network is unchanged, but the relative position of the terminal and the core network is changed, the core network can simultaneously judge the legality of the terminal and the access satellite through double identifiers in the terminal registration process, and start a same-constellation satellite legality retrieval mechanism; and based on the method for realizing the mobility management of the terminal, the safety of the terminal and the satellite access core network, the accuracy and the real-time performance of the satellite access are ensured in a more multidimensional way from the two aspects of the legality of the terminal and the satellite access and the relative position movement of the terminal initiated by the core network actively.

It should be noted that, in the embodiment of the present invention, both the validity determination and the mobility management process need to implement the terminal authentication and mobility management method for accessing the low-earth orbit satellite to the core network through the capability enhancement of the core network (the capability of the core network to configure and store ephemeris, the capability of the core network to automatically retrieve the satellite, and the capability of the core network to measure the orbit and the elevation angle of the satellite in operation) under the condition that the mobile terminal is not displaced. Specifically, the enhanced function of the core network can configure and store an ephemeris in a service area, and after the core network completes validity judgment on the mobile terminal and the access satellite, the core network can start a search function for the satellite to be switched according to the configuration of the ephemeris, so that the switching process among the satellites is actively triggered, the terminal is informed of the change condition of the access satellite, and the terminal is not required to perform signal measurement. Another enhanced capability of the core network is the measurement and determination capability of the orbit and/or elevation angle of the satellite, legal determination of the mobile terminal and the access satellite, and measurement and determination of the orbit and/or elevation angle of the access satellite by the core network in addition to inquiring the configuration of the ephemeris during the satellite switching (or redirection) process, so as to confirm the real legality of the access satellite. And the false satellite applies for access to the core network and the leakage of user information is avoided.

Referring to fig. 3, fig. 3 is a flowchart illustrating a satellite handover method according to a second embodiment of the present invention, where the method is applied to a terminal, and includes the following steps:

step 31: the method comprises the steps that a terminal receives first notification information sent by a core network, the first notification information is used for indicating that the terminal is to be accessed or resided in a second satellite, and the second satellite which the terminal is to be accessed or resided in is determined by the core network according to current position information of the terminal and an ephemeris.

The terminal is currently accessed or camped on a first satellite. The first satellite may be a non-geosynchronous orbit satellite.

In the embodiment of the invention, the core network actively pre-judges the satellite to be accessed or resided next by the terminal without signal measurement by the terminal, thereby effectively reducing the interactive resource overhead between the terminal and the satellite, reducing the energy consumption of the terminal and improving the accuracy and the real-time property of satellite access.

Optionally, the second satellite is a non-geosynchronous orbit satellite.

The embodiments of the present invention provide technical solutions corresponding to the above embodiments and having the same inventive concept, and can achieve the same technical effects.

Referring to fig. 4, fig. 4 is a schematic flowchart of a satellite handover method according to a third embodiment of the present invention, where the method is applied to a first satellite, and includes the following steps:

step 41: the method comprises the steps that a first satellite receives first notification information sent by a core network, the first notification information is used for indicating that a terminal which is currently accessed to or resides in the first satellite is to be accessed to or resides in a second satellite, and the second satellite which is accessed to or resides in the terminal is determined by the core network according to current position information of the terminal and an ephemeris.

and sending the authentication request to the core network.

In the embodiment of the invention, when the terminal is accessed to the satellite for the first time, the signaling carries the dual identifiers of the terminal and the satellite, and the user core network simultaneously completes the safety judgment of the terminal, the initial access satellite and other satellites of the galaxy where the satellite is located.

and receiving second notification information sent by the core network, wherein the second notification information comprises third notification information and/or fifth notification information, the third notification information is used for indicating the first satellite to start the switching of the terminal to the second satellite, and the fifth notification information is used for indicating the first satellite to release resources allocated to the terminal.

For example, the first satellite may send a handover request to the second satellite after receiving the third notification information, and the second satellite may allocate resources for the terminal according to the handover request.

In this embodiment of the present invention, the first notification information received by the first satellite may also be used to indicate that, after a preset time period has elapsed, if it is determined that the area to which the location of the terminal belongs does not change, the resource allocated to the terminal is released.

The embodiments of the present invention provide technical solutions corresponding to the first and second embodiments and having the same inventive concept, and can achieve the same technical effects.

Referring to fig. 5, fig. 5 is a flowchart illustrating a satellite handover method according to a fourth embodiment of the present invention, where the method is applied to a second satellite, where the second satellite is a satellite that a core network determines to access or camp on next by a terminal according to current location information of the terminal and an ephemeris, and the terminal currently accesses or camps on a first satellite, and the method includes the following steps:

step 51: the second satellite establishes a resource link with the terminal. That is, resources are allocated to the terminal.

Optionally, before establishing the resource link with the terminal, the method further includes:

receiving request information sent by a core network, wherein the request information is used for requesting the relevant information of the second satellite, and the relevant information of the second satellite comprises at least one of an identifier, a running track and a service area;

and sending the related information of the second satellite to the core network according to the request information.

Optionally, the establishing a resource link with the terminal includes:

receiving fourth notification information sent by the core network; establishing a resource link with the terminal according to the fourth notification information;

alternatively, the first and second electrodes may be,

establishing a resource link with the terminal after completing the handover with the first satellite.

The embodiments of the present invention provide technical solutions corresponding to the first to third embodiments and having the same inventive concept, and can achieve the same technical effects.

The following describes, with reference to fig. 6, an exemplary procedure of terminal connection state mobility management in a situation where the terminal is not displaced and only the satellite is handed over:

step 1: the core network automatically retrieves the satellite 2 to be accessed according to the configured ephemeris information;

and 2, step: the core network informs the satellite 1 and the terminal that the switching of the satellite 2 will occur;

and step 3: the terminal reports the GPRS position information, and the user core network judges that the position (TA) of the terminal is not changed;

and 4, step 4: the core network requests the identification of the satellite 2, the information such as the running track, the service area and the like, and the satellite 2 completes information feedback;

and 5: the core network automatically measures the orbit and elevation angle of the satellite 2, and judges the real legality of the satellite 2 again on the basis that the core network primarily authenticates the satellite 2;

and 6-7: informing the satellite 1 to switch with the satellite 2, and completing a switching preparation process among the satellites;

and 8-9: the terminal and the satellite 2 establish resource link, and the satellite 1 releases the resource link with the terminal;

step 10: the terminal is accessed through the satellite 2 and completes subsequent communication with the core network.

The following describes, with reference to fig. 7, an example of a process of idle mobility management of a terminal in a situation where the terminal is not displaced and only a satellite is handed over:

step 1: the core network automatically retrieves the satellite 2 to be resided according to the configured ephemeris information;

and 2, step: the core network informs the satellite 1 and the terminal, the redirection (reselection) of the satellite 2 occurs, and the resources of the terminal can be released within the specified time;

and 3, step 3: the terminal reports the GPRS position information, and the user core network judges that the position (TA) of the terminal is not changed;

and 4, step 4: the core network requests information such as the running track and the service area of the satellite 2;

and 5: the core network automatically measures the orbit and elevation angle of the satellite 2, and judges the real legality of the satellite 2 again on the basis that the core network primarily authenticates the satellite 2 (refer to the step of section 5.1);

step 6: the satellite 1 releases the resources with the terminal;

and 7: the core network informs the satellite 2 to establish resource link with the terminal (legal user);

and 8: the terminal is accessed through the satellite 2 and performs subsequent communication with the core network.

Referring to fig. 8, fig. 8 is a schematic structural diagram of a core network according to a fifth embodiment of the present invention, where the core network 80 includes:

the prediction module 81 is configured to determine a second satellite to be accessed or resided next by the terminal according to the current position information of the terminal and an ephemeris;

a first notification module 82, configured to send first notification information to a first satellite currently accessed by or camped on by the terminal and/or the terminal, where the first notification information is used to indicate that the terminal is to access or camp on the second satellite.

Optionally, the core network 80 further includes:

Optionally, the second notification module includes:

and the sending unit is used for sending the second notification information at the first moment according to the satellite switching or redirecting moment.

Optionally, the core network 80 further includes:

and the terminal authentication module is used for authenticating the terminal.

Optionally, the core network 80 further includes:

The embodiment of the present invention is a product embodiment corresponding to the above method embodiment, and therefore, detailed description is omitted here, and please refer to the first embodiment in detail.

Referring to fig. 9, fig. 9 is a schematic structural diagram of a terminal according to a sixth embodiment of the present invention, where the terminal 90 includes:

the first notification receiving module 91 is configured to receive first notification information sent by a core network, where the first notification information is used to indicate that the terminal is to access or camp on a second satellite, and the second satellite that the terminal is to access or camp on is determined by the core network according to current location information of the terminal and an ephemeris.

Optionally, the second satellite is a non-geosynchronous orbit satellite.

Optionally, the terminal 90 further includes:

The embodiment of the present invention is a product embodiment corresponding to the above method embodiment, and therefore, detailed description is omitted here, and please refer to the second embodiment.

Referring to fig. 10, fig. 10 is a schematic structural diagram of a first satellite 100 according to a seventh embodiment of the present invention, where the first satellite includes:

the first notification information receiving module 101 is configured to receive first notification information sent by a core network, where the first notification information is used to indicate that a terminal currently accessing or residing in a first satellite will access or reside in a second satellite, and the second satellite that the terminal will access or reside in is determined by the core network according to current location information of the terminal and an ephemeris.

Optionally, the first satellite 100 further includes:

The embodiment of the present invention is a product embodiment corresponding to the third embodiment of the method, and therefore, detailed description is omitted here, and please refer to the third embodiment.

Referring to fig. 11, fig. 11 is a schematic structural diagram of a core network according to an eighth embodiment of the present invention, where the core network 110 includes: a transceiver 111 and a processor 112;

the processor 112 is configured to determine a second satellite to be accessed or camped next by the terminal according to the current position information of the terminal and an ephemeris;

the transceiver 111 is configured to send first notification information to a first satellite currently accessed or camped on by the terminal and/or the terminal, where the first notification information is used to indicate that the terminal is to access or camp on the second satellite.

Optionally, the transceiver 111 is further configured to send second notification information when it is determined that the area to which the location of the terminal belongs is not changed; the second notification information includes at least one of:

third notification information used for sending to the first satellite, wherein the third notification information is used for instructing the first satellite to start the switch of the terminal to the second satellite;

Optionally, the processor 112 is configured to determine a time for satellite handover or redirection;

the transceiver 111 is configured to send the second notification information at a first time according to the time of the satellite switching or redirection.

Optionally, the transceiver 111 is further configured to receive location information reported by the terminal;

the processor 112 is further configured to determine, according to the location information, that the area to which the location of the terminal belongs does not change.

Optionally, the transceiver 111 is further configured to send request information to the second satellite, where the request information is used to request information related to the second satellite, and the information related to the second satellite includes at least one of an identifier, a trajectory, and a service area;

the transceiver 111 is further configured to receive information related to the second satellite, which is sent by the second satellite according to the request information;

the processor 112 is further configured to determine the authenticity of the second satellite according to the information related to the second satellite and the ephemeris.

Optionally, the transceiver 111 is further configured to measure the orbit and/or the elevation angle of the second satellite;

the processor 112 is further configured to determine the true validity of the second satellite according to the measured orbit and/or the elevation angle of the second satellite and the ephemeris.

Optionally, the transceiver 111 is further configured to receive an authentication request sent by the terminal through the first satellite, where the authentication request includes an identifier of the terminal and a first identifier, and the first identifier is an identifier of the first satellite;

the transceiver 111 is further configured to measure the orbit and/or elevation angle of the first satellite;

the processor 112 is further configured to determine the true validity of the first satellite according to the measured orbit and/or the elevation angle of the first satellite and the ephemeris;

the processor 112 is further configured to authenticate the terminal.

Optionally, the processor 112 is further configured to start a pre-determination of the real legitimacy of other satellites of the constellation system in which the first satellite is located, where the other satellites include the second satellite.

Referring to fig. 12, fig. 12 is a schematic structural diagram of a terminal according to a ninth embodiment of the present invention, where the terminal 120 includes: a transceiver 121 and a processor 122;

the transceiver 121 is configured to receive first notification information sent by a core network, where the first notification information is used to indicate that the terminal is to access or camp on a second satellite, and the second satellite that the terminal is to access or camp on is determined by the core network according to current location information of the terminal and an ephemeris.

Optionally, the second satellite is a non-geosynchronous orbit satellite.

Optionally, the transceiver 121 is further configured to report location information to the core network, so that the core network determines whether an area to which the location of the terminal belongs changes according to the location information of the terminal.

Referring to fig. 13, fig. 13 is a schematic structural diagram of a first satellite 130 according to a tenth embodiment of the present invention, where the first satellite includes: a transceiver 131 and a processor 132;

the transceiver 131 is configured to receive first notification information sent by a core network, where the first notification information is used to indicate that a terminal currently accessing or residing in a first satellite will access or reside in a second satellite, and the second satellite to which the terminal will access or reside is determined by the core network according to current location information of the terminal and an ephemeris.

Optionally, the transceiver 131 is further configured to receive an authentication request sent by the terminal, where the authentication request includes an identifier of the terminal;

the processor 132 is configured to add a first identifier to the authentication request, where the first identifier is an identifier of the first satellite;

the transceiver 131 is further configured to send the authentication request to the core network.

Optionally, the transceiver 131 is further configured to receive second notification information sent by the core network, where the second notification information includes third notification information and/or fifth notification information, the third notification information is used to instruct the first satellite to start the handover from the terminal to the second satellite, and the fifth notification information is used to instruct the first satellite to release resources allocated to the terminal.

Optionally, the processor 132 is configured to determine whether an area to which the position of the terminal belongs changes after a preset time period elapses;

the processor 132 is further configured to release the resource allocated to the terminal if the area to which the location of the terminal belongs does not change.

Referring to fig. 14, fig. 14 is a schematic structural diagram of a core network according to an eleventh embodiment of the present invention, where the core network 140 includes a processor 141, a memory 142, and a program stored in the memory 142 and capable of running on the processor 141; the processor 141, when executing the program, implements the following steps:

Optionally, the processor 141 may further implement the following steps when executing the program:

after the sending the first notification information to the first satellite currently accessed or camped on by the terminal and/or the terminal, the method further includes:

the sending the second notification information includes:

determining the moment of satellite switching or redirection;

receiving the position information reported by the terminal;

before the sending the second notification information, the method further includes:

measuring the orbit and/or elevation angle of the second satellite;

the determining, according to the current location information of the terminal and the ephemeris, before a second satellite to be accessed or to be parked by the terminal next time, further includes:

measuring the orbit and/or elevation of the first satellite;

and authenticating the terminal.

after receiving the authentication request sent by the terminal through the first satellite, the method further includes:

The specific working process of the embodiment of the present invention is the same as that of the first embodiment of the method, and therefore, details are not repeated here, and please refer to the description of the method steps in the first embodiment.

Referring to fig. 15, fig. 15 is a schematic structural diagram of a terminal according to a twelfth embodiment of the present invention, where the terminal 150 includes a processor 151, a memory 152, and a program stored in the memory 152 and capable of running on the processor 151; the processor 151, when executing the program, implements the following steps:

Optionally, the second satellite is a non-geosynchronous orbit satellite.

Optionally, when the processor 151 executes the program, the following steps may be further implemented:

after receiving the first notification information sent by the core network, the method further includes:

The specific working process of the embodiment of the present invention is the same as that of the second embodiment of the method, and therefore, the detailed description thereof is omitted, and refer to the description of the method steps in the second embodiment.

Referring to fig. 16, fig. 16 is a schematic structural diagram of a first satellite according to a thirteenth embodiment of the present invention, where the first satellite 160 includes a processor 161, a memory 162, and a program stored in the memory 162 and capable of running on the processor 161; the processor 161, when executing the program, implements the steps of:

receiving first notification information sent by a core network, wherein the first notification information is used for indicating that a terminal which is currently accessed to or resides in a first satellite is to be accessed to or resides in a second satellite, and the second satellite which is to be accessed to or resides in the terminal is determined by the core network according to the current position information of the terminal and an ephemeris.

Optionally, when the processor 161 executes the program, the following steps may also be implemented:

before the receiving the first notification information sent by the core network, the method further includes:

and sending the authentication request to the core network.

Optionally, when the processor 161 executes the program, the following steps may be further implemented:

The specific working process of the embodiment of the present invention is the same as that of the third embodiment of the method, and therefore, the detailed description thereof is omitted, and please refer to the description of the method steps in the third embodiment.

A fourteenth embodiment of the present invention provides a readable storage medium, where a program is stored, and the program, when executed by a processor, implements the steps in any one of the satellite switching methods in the first to the fourth embodiments. Please refer to the above description of the method steps in the corresponding embodiments.

The terminal in the embodiments of the present invention may be a wireless terminal or a wired terminal, and the wireless terminal may be a device providing voice and/or other service data connectivity to a user, a handheld device having a wireless connection function, or other processing devices connected to a wireless modem. A wireless terminal, which may be a mobile terminal such as a mobile telephone (or "cellular" telephone) and a computer having mobile terminals, e.g., portable, pocket, hand-held, computer-included, or vehicle-mounted mobile devices, may communicate with one or more core networks via a Radio Access Network (RAN), which may exchange speech and/or data with the RAN. For example, devices such as Personal Communication Service (PCS) phones, cordless phones, Session Initiation Protocol (SIP) phones, Wireless Local Loop (WLL) stations, and Personal Digital Assistants (PDAs) are used. A wireless Terminal may also be referred to as a system, a Subscriber Unit (Subscriber Unit), a Subscriber Station (Subscriber Station), a Mobile Station (Mobile), a Remote Station (Remote Station), a Remote Terminal (Remote Terminal), an Access Terminal (Access Terminal), a User Terminal (User Terminal), a User Agent (User Agent), and a Terminal (User Device or User Equipment), which are not limited herein.

The readable storage medium includes a computer readable storage medium. Computer-readable storage media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of storage media include, but are not limited to, phase change memory (PRAM), Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), Digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A satellite switching method is applied to a core network, and is characterized by comprising the following steps:

2. The method of claim 1, wherein the first satellite and the second satellite are non-geosynchronous orbit satellites.

3. The method according to claim 2, wherein after the sending the first notification information to the first satellite currently accessed or camped by the terminal and/or the terminal, further comprising:

4. The method of claim 3, wherein sending the second notification information comprises:

determining the moment of satellite switching or redirection;

5. The method according to any one of claims 1 to 3, wherein after the sending the first notification information to the first satellite currently accessed or camped by the terminal and/or the terminal, further comprising:

receiving the position information reported by the terminal;

6. The method according to claim 1, wherein the first notification information sent to the first satellite is further used to instruct the first satellite to release the resource allocated to the terminal if it is determined that the area to which the location of the terminal belongs has not changed after a preset time period elapses.

7. The method of claim 3, wherein before sending the second notification information, further comprising:

8. The method of claim 3 or 7, wherein before sending the second notification information, further comprising:

measuring the orbit and/or elevation angle of the second satellite;

9. The method according to claim 1 or 2, wherein the determining of the second satellite to be accessed or resided next by the terminal according to the current position information of the terminal and the ephemeris further comprises:

measuring the orbit and/or elevation of the first satellite;

and authenticating the terminal.

10. The method of claim 9, wherein after receiving the authentication request sent by the terminal through the first satellite, the method further comprises:

11. A satellite switching method is applied to a terminal and is characterized by comprising the following steps:

12. The method of claim 11, wherein the second satellite is a non-geosynchronous orbit satellite.

13. The method according to claim 11 or 12, wherein after receiving the first notification information sent by the core network, the method further comprises:

14. A satellite switching method is applied to a first satellite, and is characterized by comprising the following steps:

15. The method of claim 14, wherein the first satellite and the second satellite are non-geosynchronous orbit satellites.

16. The method of claim 14, wherein before receiving the first notification information sent by the core network, the method further comprises:

and sending the authentication request to the core network.

17. The method of claim 14, wherein after receiving the first notification message sent by the core network, the method further comprises:

18. The method of claim 14, wherein after receiving the first notification message sent by the core network, the method further comprises:

19. A core network, comprising:

20. A terminal, comprising:

21. A first satellite, comprising:

22. A core network, comprising: a transceiver and a processor;

23. A terminal, comprising: a transceiver and a processor;

24. A first satellite, comprising: a transceiver and a processor;

25. A core network comprising a memory, a processor and a program stored on the memory and executable on the processor; characterized in that the processor, when executing the program, implements the steps in the satellite switching method according to any one of claims 1 to 10.

26. A terminal comprising a memory, a processor, and a program stored on the memory and executable on the processor; characterized in that the processor, when executing the program, implements the steps in the satellite switching method according to any one of claims 11 to 13.

27. A first satellite comprising a memory, a processor, and a program stored on the memory and executable on the processor; a method for performing a satellite handover as claimed in any one of claims 14 to 18, when the program is executed by the processor.

28. A readable storage medium, on which a program is stored which, when being executed by a processor, carries out the steps of the satellite switching method according to one of claims 1 to 10 or the steps of the satellite switching method according to one of claims 11 to 13 or the steps of the satellite switching method according to one of claims 14 to 18.