Communication method and related apparatus

Abstract

A communication method and a related apparatus. First information received by a first communication apparatus is used for indicating information of N satellite beams, and the first communication apparatus can determine, on the basis of the information of the N satellite beams, a target satellite beam that communicates with a first terminal device. In each of K time periods, a signal coverage area of at least one of the N satellite beams comprises a first geographic area, and when the first communication apparatus receives the first information, a terminal device located in the first geographic area includes the first terminal device. In other words, any terminal device located in the first geographic area can determine the target satellite beam on the basis of the information of the N satellite beams indicated by the first information. In this way, one or more terminal devices located in a same geographic area can determine the target satellite beam on the basis of the first information, thereby reducing transmission overheads.

Description

Communication method and related apparatus

[0001] This application claims priority to the Chinese Patent Application No. CN202411359714.1, filed on September 26, 2024, and titled "A communication method and related apparatus", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of communication, and in particular, to a communication method and related apparatus. BACKGROUND

[0003] Wireless communication can be transmission communication between two or more communication devices without propagating through a conductor or cable. The communication devices generally include network devices and terminal devices. Traditional network devices can be devices fixed on the ground, such as ground base stations belonging to terrestrial network (TN) cells.

[0004] With the development of communication technology, network devices can not be fixed on the ground. For example, the network devices can be high-speed mobile devices belonging to non-terrestrial network (NTN) cells, including but not limited to satellite devices such as low-orbit satellites, medium-orbit satellites, and high-orbit satellites.

[0005] Generally, in the beam-based communication mode between the terminal devices and the network devices, unlike the ground base stations belonging to the TN cells, the satellite devices belonging to the NTN cells can move at high speed, which can cause the satellite beams used by the terminal devices to change frequently. The changed satellite beams can be referred to as target satellite beams.

[0006] However, in the above process, each terminal device needs to determine the target satellite beam corresponding to the terminal device through an independent signaling transmission process. This method can cause a sharp increase in signaling overhead, and further increase the power consumption of the terminal device. SUMMARY

[0007] The present application provides a communication method and related apparatus for reducing signaling overhead and reducing the power consumption of the communication device.

[0008] The first aspect of the present application provides a communication method, which is applied to a first communication device, for example, the method is executed by the first communication device. Wherein the first communication device can be a communication equipment (such as a first terminal device), or the first communication device can be a part of the communication equipment (for example, a circuit or a chip responsible for communication function (such as a Modem chip, also known as a baseband chip, or a system on chip (SoC) chip or a system in package (SIP) chip containing a modem core) and the like), or the first communication device can also be a logic module or software that can realize all or part of the communication equipment function.

[0009] In the method, the first communication device receives first information, the first information is used to indicate information of N satellite beams; in each time period of K time periods, a signal coverage area of at least one satellite beam in the N satellite beams includes a first geographic area; wherein the K time periods are continuous time periods with the same time length, K and N are positive integers; when receiving the first information, a terminal device located in the first geographic area includes a first terminal device; the first communication device determines a target satellite beam for communicating with the first terminal device based on the information of the N satellite beams, and the target satellite beam is included in the N satellite beams.

[0010] Based on the above scheme, the first communication device receives first information used to indicate information of N satellite beams, and the first communication device can determine a target satellite beam for communicating with the first terminal device based on the information of the N satellite beams. Wherein in each time period of K time periods, a signal coverage area of at least one satellite beam in the N satellite beams includes a first geographic area, and when the first communication device receives the first information, a terminal device located in the first geographic area includes a first terminal device. In other words, any terminal device located in the first geographic area can determine a target satellite beam based on the information of the N satellite beams indicated by the first information. In this way, one or more terminal devices located in the same geographic area can determine a target satellite beam based on the first information, which can reduce transmission overhead, and a faster search for a target satellite beam based on the first information can be performed, thereby reducing the power consumption of one or more terminal devices and improving communication efficiency.

[0011] In addition, in each time period of the K time periods, a signal coverage area of at least one satellite beam of the N satellite beams comprises the first geographic area. For a terminal device (e.g., the first terminal device) located in the first geographic area, the terminal device can determine a target satellite beam according to the satellite beam information of any time period of the K time periods, thereby solving the problem that the terminal device cannot obtain a satellite beam serving a geographic area where the terminal device is located after the satellite moves, so that the terminal device can quickly access a target satellite beam in a low-orbit satellite fast-moving scenario, and high power consumption of the terminal device caused by blind search for a satellite beam is reduced.

[0012] It should be understood that the scheme provided in the present application can be applied to a beam-based communication scenario, and beams are taken as satellite beams for example in the present article. Alternatively, the satellite beams can be replaced by other terms, such as beams, cells, satellite cells, communication beams, satellite communication beams, NTN beams, NTN communication beams.

[0013] It should be understood that the signal coverage area of a satellite beam can be understood as a geographic area where a signal of the satellite beam is reachable / servable / available for communication. For example, the signal coverage area of a satellite beam can comprise one or more geographic areas, and a terminal device located in the one or more geographic areas can communicate through the satellite beam.

[0014] Alternatively, the signal coverage area can be replaced by other terms, such as a servable area, a service area, a signal available area, a signal reachable area, a communication area, or a communicable area, etc.

[0015] It should be understood that the K time periods are continuous time periods with the same length, which can be understood as follows: the K time periods are connected at the head and tail, and each time period has the same length; or, a termination time of a k(th) (k is an integer from 1 to K-1) time period of the K time periods is a start time of a (k+1)th time period of the K time periods, a start time of the k(th) time period is a termination time of a (k-1)th time period of the K time periods; or, a last time unit of the k(th) (k is an integer from 1 to K-1) time period of the K time periods is adjacent to a start time unit of the (k+1)th time period of the K time periods, where the time unit can be a symbol, a time slot, a subframe, a frame, a millisecond, a microsecond, a minute, a second, or a minute, etc.

[0016] Alternatively, the time period can be replaced by other terms, such as a time slice, or a time block, etc.

[0017] Alternatively, the information of the N satellite beams can be referred to as auxiliary information of the N satellite beams.

[0018] In a possible implementation of the first aspect, in each of the K time periods, a signal coverage area of at least one of the N satellite beams includes a second geographic area, and the first geographic area is adjacent to the second geographic area. Accordingly, when the first terminal device moves from the first geographic area to the second geographic area, the first terminal device can determine the target satellite beam according to the information that at least one of the N satellite beams has a coverage area including the second geographic area in any of the K time periods. In this way, after the first terminal device moves from the first geographic area to the second geographic area, the first terminal device can still determine the target satellite beam by using the first information, thereby maintaining continuity of communication. Compared with the terminal device blindly searching for a satellite and a satellite beam without the first information in any of the K time periods, a time delay of satellite and cell searching can be greatly reduced, thereby reducing a service time delay, improving a service experience, and reducing power consumption of the terminal device, to improve communication efficiency.

[0019] It should be noted that the first geographic area and the second geographic area can have a partially overlapping area, or can have no overlapping area, which is not limited herein.

[0020] In a possible implementation of the first aspect, the first communication device determines the target satellite beam for communicating with the first terminal device based on the information of the N satellite beams, including: the first communication device determines M satellite beams from the N satellite beams based on the information of the N satellite beams, the M satellite beams being used to determine the target satellite beam; and any of the M satellite beams has a signal coverage area including a geographic area where the first terminal device currently locates, the geographic area where the first terminal device currently locates being included in the first geographic area or the second geographic area, and M being less than or equal to N.

[0021] Based on the above scheme, the first communication device can determine M satellite beams from the N satellite beams, that is, the M satellite beams can be candidate satellite beams. Moreover, any of the M satellite beams has a signal coverage area including the geographic area where the first terminal device currently locates, so that the first communication device can select / determine the target satellite beam from the candidate satellite beams serving the geographic area where the first terminal device currently locates, and can achieve fast determination of the target satellite beam, while avoiding a situation of communication failure caused by determining a satellite beam whose signal coverage area does not include the geographic area where the first terminal device currently locates as the target satellite beam.

[0022] Optionally, in a case where the first terminal device moves in the first geographic area or remains stationary, the geographic area where the first terminal device currently locates is included in the first geographic area.

[0023] Optionally, in a case that the first terminal device moves from the first geographic region to a second geographic region, the geographic region where the first terminal device currently locates is included in the second geographic region.

[0024] In a possible implementation of the first aspect, in the N satellite beams, the M satellite beams serve the geographic region where the first terminal device currently locates for a time duration that is greater than or equal to a time duration for which the other N-M satellite beams serve the geographic region where the first terminal device currently locates.

[0025] Based on the above scheme, in the N satellite beams, the M satellite beams serving the geographic region where the first terminal device currently locates have a longer time duration, and in this way, the first communication apparatus can select the M satellite beams with a longer time duration as candidate beams, and can select a satellite beam with a longer time duration as a target communication beam as much as possible, so that the frequency of re-determining a target satellite beam (for example, beam switching / beam reselection) can be reduced, and further, the communication overhead can be reduced.

[0026] Optionally, the time duration for which a satellite beam serves a geographic region can be understood as a service time duration for which the satellite beam serves the geographic region, a remaining service time duration, a remaining serviceable time duration, an available time duration, a remaining available time duration, a communication time duration, a remaining communication time duration, a communicable time duration, or a remaining communicable time duration.

[0027] In a possible implementation of the first aspect, the method further includes: receiving, by the first communication apparatus, at least one signal from part or all of the M satellite beams, and a measurement result of the at least one signal is used to determine the target satellite beam from the M satellite beams.

[0028] Based on the above scheme, the first communication apparatus can further receive at least one signal from part or all of the M satellite beams, and perform measurement based on the at least one signal to obtain a measurement result used to determine the target satellite beam. In this way, the first communication apparatus can determine / select a satellite beam with better signal quality from the M candidate satellite beams as the target satellite beam, so as to improve the communication quality of subsequent communication of the first communication apparatus based on the target satellite beam.

[0029] Optionally, the measurement result can be used to characterize the signal quality, for example, the measurement result can include one or more of a reference signal receiving power (RSRP), a reference signal receiving quality (RSRQ), a signal and interference plus noise ratio (SINR), or other parameters.

[0030] In a possible implementation of the first aspect, the information of the satellite beam includes at least one of: information of a satellite corresponding to the satellite beam, communication frequency information of the satellite beam, cell information corresponding to the satellite beam, geographical area information covered by the satellite beam, or service time information of the satellite beam.

[0031] Based on the above scheme, the information of the satellite beam can include the at least one described above, to improve the flexibility of the scheme implementation.

[0032] For example, the information of the satellite corresponding to the satellite beam can indicate the satellite corresponding to the satellite beam, for example, the information of the satellite corresponding to the satellite beam can include one or more of an identifier of the satellite, a number of the satellite, an ephemeris of the satellite, coordinates of the satellite, and a time at which the coordinates are located, or other information.

[0033] For another example, the communication frequency information of the satellite beam can indicate the communication frequency corresponding to the satellite beam, for example, the communication frequency information of the satellite beam can include a start frequency point and / or an end frequency point of the communication frequency, or the communication frequency information of the satellite beam can include an index corresponding to the communication frequency.

[0034] For another example, the cell information corresponding to the satellite beam can indicate the cell corresponding to the satellite beam, for example, the cell information corresponding to the satellite beam can include one or more of a cell identifier (cell ID) of the cell, a physical cell identifier (PCI), or other information.

[0035] For another example, the geographical area information covered by the satellite beam can be understood as the geographical area information of the signal coverage range of the satellite beam. For example, the geographical area information covered by the satellite beam can indicate one or more geographical areas contained in the signal coverage range of the satellite beam, or the geographical area information covered by the satellite beam can also be identifier information of a ground fixed cell / area.

[0036] For another example, the service time information of the satellite beam can indicate one or more of a start time information (e.g., a start time or a start time unit), a duration, and a termination time information (e.g., a termination time or a termination time unit) of the service of the satellite beam. For an example, the service time of the satellite beam refers to a time when the satellite beam serves the geographic area covered by the satellite beam included in the information of the satellite beam.

[0037] In a possible implementation of the first aspect, the method further includes: receiving, by the first communication device, a first signal of the target satellite beam, the first signal being used for synchronization; and camping, by the first terminal device, on a target satellite cell (or a target satellite network device) corresponding to the target satellite beam after the first terminal device obtains synchronization (e.g., downlink synchronization) based on the target satellite beam.

[0038] Optionally, the performing, by the first communication device, the RACH procedure through the target beam includes: sending, by the first communication device, a RACH request message through the target beam.

[0039] Based on the above scheme, the first communication device can receive a first signal of the target satellite beam for synchronization, so that the first terminal device can camp on a target satellite cell (or a target satellite network device) corresponding to the target satellite beam after the first terminal device obtains synchronization (e.g., downlink synchronization) based on the target satellite beam. Optionally, in a case where the first terminal device is in a radio resource control idle state (RRC_IDLE) or a radio resource control inactive state (RRC_INACTIVE), the first terminal device camps on the target satellite cell (or the target satellite network device) corresponding to the target satellite beam. For example, the camping of the terminal device on the target satellite cell means that the terminal device maintains downlink synchronization with the target satellite cell and can receive broadcast messages and paging messages from the target satellite cell.

[0040] Alternatively, the first communication device can perform a RACH procedure through the target beam, so that the first terminal device can be switched from a source network device to a target satellite network device corresponding to the target satellite beam. Optionally, in a case where the first terminal device is in a radio resource control connected state (RRC_CONNECTED), the first terminal device can also camp on the target satellite cell (or the target satellite network device) corresponding to the target satellite beam, that is, without initiating the RACH procedure.

[0041] Optionally, the first terminal device can be in RRC_IDLE or RRC_INACTIVE when receiving the first information. The first terminal device can camp on a source cell. Alternatively, the first terminal device can be in RRC_CONNECTED when receiving the first information, and the first terminal device can establish a radio resource control (RRC) connection with the source cell. The source cell can be a TN cell, i.e., the network device corresponding to the source cell can be a TN network device, or the source cell can be an NTN cell, i.e., the network device corresponding to the source cell can be an NTN network device or a source satellite network device.

[0042] In a possible implementation of the first aspect, the receiving time or the sending time of the first information is within a first time period (which can be any of the K time periods); and the first communication apparatus performs the RACH procedure through the target beam in any of the following ways:

[0043] The first communication apparatus performs the RACH procedure through the target beam at a start time (or a start time point) of a next time period of the first time period; or

[0044] The first communication apparatus performs the RACH procedure through the target beam at a start time (or a start time point) of a next time period of the first time period and delays for a first time duration, the number of time units included in the first time duration being determined based on a random number, and the number of time units included in the first time duration being less than or equal to a threshold.

[0045] Based on the above scheme, the first communication apparatus can perform the RACH procedure based on any of the above schemes to improve the flexibility of the implementation of the scheme. In addition, in the case where the first communication apparatus performs the RACH procedure based on the first time duration, since the number of time units included in the first time duration is determined based on a random number, one or more terminal devices located in the same geographical area (for example, the first geographical area) can perform the RACH procedure based on the random number within a specified time duration, which can not only enable the one or more terminal devices to complete access within the specified time duration, but also can avoid or reduce the occurrence of conflicts caused by different terminal devices performing the RACH procedure at the same time, thereby improving the communication efficiency.

[0046] In a possible implementation of the first aspect, the method further includes: the first communication apparatus receiving second information, the second information being used to indicate switching a source satellite beam to which the first terminal device is connected; and the first communication apparatus performing the RACH procedure through the target beam in any of the following ways:

[0047] The first communication apparatus performs the RACH procedure via the target beam immediately after receiving the second information; or

[0048] The first communication apparatus performs the RACH procedure via the target beam after delaying for a second time duration after receiving the second information, a quantity of time units included in the second time duration is determined based on a random number, and the quantity of time units included in the second time duration is less than or equal to a threshold value.

[0049] Based on the above scheme, the first communication apparatus can perform the RACH procedure based on any of the above to improve the flexibility of the scheme implementation. And in the case where the first communication apparatus performs the RACH procedure based on the second time duration, since the quantity of time units included in the second time duration is determined based on a random number, one or more terminal devices located in the same geographic area (e.g., the first geographic area) can perform the RACH procedure based on the random number within a specified time duration, which can not only enable the one or more terminal devices to complete access within the specified time duration, but also avoid or reduce the occurrence of conflicts caused by different terminal devices performing the RACH procedure at the same time, thereby improving communication efficiency.

[0050] Optionally, the second information can be sent in a broadcast or groupcast manner, and correspondingly, the second information is used to indicate switching of a source satellite beam to which one or more terminal devices (including the first terminal device) located in the same geographic area (e.g., the first geographic area) are connected. In this way, the second information can implement batch switching indication of the one or more terminal devices in the same geographic area, thereby reducing overhead.

[0051] In a possible implementation form of the first aspect, the first information is also used to indicate switching of the source satellite beam to which the first terminal device is connected.

[0052] Based on the above scheme, in addition to the information used to indicate the N satellite beams, the first information can also be used to indicate switching of the source satellite beam to which the first terminal device is connected, which can multiplex the first information to indicate more information, thereby reducing overhead.

[0053] Optionally, the first information is also used to indicate switching of a source satellite beam to which one or more terminal devices (including the first terminal device) located in the same geographic area (e.g., the first geographic area) are connected. In this way, the first information can implement batch switching indication of the one or more terminal devices in the same geographic area, thereby reducing overhead.

[0054] In a possible implementation form of the first aspect, the method further includes: the first communication apparatus sending third information, the third information being used to request switching of the first terminal device from a source satellite beam to a target satellite beam.

[0055] Based on the above scheme, when the first communication device moves from the first geographic area to the second geographic area, the first communication device can further send third information for requesting to switch the first terminal device from the source satellite beam to the target satellite beam, so that the receiver of the third information can initiate a switching process of the first terminal device based on the request to realize switching of the satellite cell or the satellite network device connected by the first terminal device.

[0056] Optionally, the third information comprises an identifier of the target satellite beam and / or an identifier of the target satellite cell, so that the receiver of the third information switches the first terminal device to the target satellite cell or the target satellite network device corresponding to the target satellite beam based on the identifier.

[0057] In a possible implementation of the first aspect, the first information is carried in a multicast message or a broadcast message.

[0058] Based on the above scheme, the first information received by the first communication device can be carried in a multicast message or a broadcast message, so that one or more terminal devices can obtain the first information through the multicast message or the broadcast message, and the transmission overhead of the information of the satellite beam can be reduced.

[0059] In a possible implementation of the first aspect, the second information is carried in a multicast message or a broadcast message.

[0060] Based on the above scheme, the second information received by the first communication device can be carried in a multicast message or a broadcast message (i.e., the second information can be sent in a broadcast or multicast manner), so that one or more terminal devices can obtain the second information through the multicast message or the broadcast message, and the transmission overhead of the switching indication can be reduced.

[0061] The second aspect of the present application provides a communication method, which is applied to a second communication device, such as being executed by the second communication device. The second communication device can be a communication device (e.g., a first network element or a source satellite network device), or the second communication device can be a part of the communication device (e.g., a circuit or a chip responsible for communication functions (such as a Modem chip, also known as a baseband chip, or a SoC chip or a SIP chip containing a modem core, etc.), or the second communication device can also be a logic module or software capable of realizing all or part of the functions of the communication device.

[0062] In the method, the second communication device acquires first information, the first information being used to indicate information of N satellite beams, in each time period of K time periods, a signal coverage area of at least one satellite beam of the N satellite beams comprises a first geographic area; wherein the K time periods are continuous time periods with the same time length, K and N are positive integers; when the first information is received, a terminal device located in the first geographic area comprises a first terminal device; the information of the N satellite beams is used to determine a target satellite beam for communication with the first terminal device, the target satellite beam being included in the N satellite beams; and the second communication device sends the first information.

[0063] Based on the above scheme, the first information sent by the second communication device is used to indicate information of N satellite beams, so that a receiver of the first information can determine a target satellite beam for communication with the first terminal device based on the information of the N satellite beams. Wherein, in each time period of K time periods, a signal coverage area of at least one satellite beam of the N satellite beams comprises a first geographic area, and when the receiver receives the first information, a terminal device located in the first geographic area comprises a first terminal device. In other words, any terminal device located in the first geographic area can determine a target satellite beam based on the information of the N satellite beams indicated by the first information. In this way, one or more terminal devices located in the same geographic area can determine a target satellite beam based on the first information, which can reduce transmission overhead, and a target satellite beam can be searched more quickly based on the first information, thereby reducing the power consumption of one or more terminal devices and improving communication efficiency.

[0064] In addition, in each time period of K time periods, a signal coverage area of at least one satellite beam of the N satellite beams comprises a first geographic area. For a terminal device (such as the first terminal device) located in the first geographic area, the terminal device can determine a target satellite beam according to satellite beam information in any time period of the K time periods, which solves the problem that a terminal device cannot obtain a satellite beam serving a geographic area where the terminal device is located after the satellite moves, compared with traditional technologies, so that in a low-orbit satellite fast-moving scenario, a terminal device can quickly access a target satellite beam, and high power consumption of the terminal device caused by blind search for a satellite beam is reduced.

[0065] Optionally, the N satellite beams correspond to one or more satellite network devices, and the information of the N satellite beams is determined based on one or more of ephemeris information of the one or more satellite network devices, topology information of the one or more satellite network devices, or configuration information of a constellation. For example, the second communication apparatus can determine the information of the N satellite beams based on the ephemeris information of the one or more satellite network devices and / or the topology information of a constellation to which the one or more satellite network devices correspond. The topology information of the constellation indicates the deployment of the satellites in the constellation, and based on the topology information of the satellites, the position and the velocity of each satellite in the constellation at any time can be determined. For example, the topology information of the constellation can include the ephemeris information of each satellite in the constellation. In addition, the configuration information of the constellation can include one or more of the frequency used by the satellite beams of the satellites in the constellation, the staring time period information (i.e., the length of time for serving a geographical area) and the staring time of the satellite beams, and the physical cell identity corresponding to the satellite beams.

[0066] It should be noted that the frequency used by the satellite beams can be related to the geographical area served by the satellite beams, for example, different frequencies are used when the same satellite beam of the same satellite serves different geographical areas. The frequency used by the satellite beams can also be independent of the geographical area served by the satellite beams, i.e., the same frequency is used by the satellite beams when serving any geographical area. The staring time period and the staring time of the satellite beams can be configured to be the same for the entire constellation, i.e., the staring time period and the staring time of any satellite beam of any satellite in the entire constellation are the same, for example, all satellite beams start to stare at a ground area at time t1, and change the ground area they stare at with a period T. The staring time period and the staring time of the satellite beams can also be configured per satellite, i.e., the staring time period and the staring time of the satellite beams of different satellites can be different.

[0067] As an example, the second communication apparatus can be a first network element or a part of the first network element, i.e., the information of the N satellite beams can be determined by the first network element. The first network element can be a topology service or a topology server in a non-terrestrial network, or the first network element can be a topology service or a topology server in a satellite network, or the first network element can be a hardware and / or software module integrated in a network device, which can be an access network device or a core network device. In the above scheme, the second communication apparatus can send the first information to a network device (e.g., a source satellite network device), or the second communication apparatus can send the first information to a terminal device (e.g., one or more terminal devices located in the first geographical area), or the second communication apparatus can send the first information to a terminal device (e.g., one or more terminal devices located in the first geographical area) through a network device (e.g., a source satellite network device).

[0068] As another example, the second communication device can be a source network device (e.g., a source satellite network device) or a part of component in the source network device, i.e., the information of the N satellite beams can be determined by the source network device. Wherein, the source network device can be an NTN network device, which can be referred to as a source satellite network device, and hereinafter, the source network device is taken as the source satellite network device as an example for description. In the above scheme, the second communication device can send the first information to the terminal device (e.g., one or more terminal devices located in the first geographic region).

[0069] Optionally, the second communication device can acquire the first information in a manner of locally determining the first information. For example, the second communication device can determine the information of the N satellite beams based on one or more of the following: ephemeris information of the one or more satellite network devices, topology information of a constellation corresponding to the one or more satellite network devices, and configuration information of the constellation.

[0070] Alternatively, the second communication device can acquire the first information in a manner of receiving the first information. For example, the first information can come from the first network element.

[0071] In a possible implementation manner of the second aspect, the method further includes: the second communication device sending second information, the second information being used to indicate switching of a source satellite beam to which the first terminal device is connected; or, the first information is further used to indicate switching of the source satellite beam to which the first terminal device is connected.

[0072] Based on the above scheme, the second communication device can indicate switching of the source satellite beam to which the first terminal device is connected through the sent first information or the second information, so that the first terminal device can perform an RCH procedure with a target satellite cell or a target satellite network device corresponding to a target satellite beam based on the indication of the first information or the second information, to realize switching.

[0073] Optionally, the first information or the second information is used to indicate switching of a source satellite beam to which one or more terminal devices (including the first terminal device) located in a same geographic region (e.g., the first geographic region or the second geographic region) are connected. In this way, the first information or the second information can realize batch switching indication of the one or more terminal devices located in the same geographic region, to reduce overhead.

[0074] In a possible implementation manner of the second aspect, the method further includes: after the second communication device sends the first information or the second information, the second communication device starts to cache data packets of one or more terminal devices located in the first geographic region.

[0075] Based on the above scheme, after the second communication device sends the first information or the second information, the second communication device can determine that handover of one or more terminal devices located in the first geographic area is likely to occur. To this end, the second communication device can start buffering data packets of the one or more terminal devices located in the first geographic area, so that the target satellite network device after handover can obtain the data packets buffered by the second communication device, preventing or reducing the occurrence of packet loss during terminal cross-satellite beam handover, and improving service continuity.

[0076] Optionally, after the second communication device sends the first information or the second information, the second communication device can buffer data packets of one or more terminal devices located in the first geographic area in various ways.

[0077] For example, after sending the first information or the second information or at the start of the next time period of the above-mentioned first time period, the second communication device immediately starts buffering data packets of one or more terminal devices located in the first geographic area.

[0078] In a possible implementation of the second aspect, the method further includes: the second communication device receiving third information, the third information being used to request handover of the first terminal device from a source satellite beam to the target satellite beam.

[0079] Based on the above scheme, the second communication device can also receive third information used to request handover of the first terminal device from a source satellite beam to the target satellite beam, so that the second communication device can perform a RACH procedure of the first terminal device based on the request, to realize handover of a satellite cell or a satellite network device connected by the first terminal device.

[0080] In a possible implementation of the second aspect, the method further includes: the second communication device determining P candidate satellite beams from the N satellite beams, P being less than or equal to N; and the second communication device sending fourth information to one or more satellite network devices corresponding to the P satellite beams, the fourth information including context information of one or more terminal devices located in the first geographic area.

[0081] Based on the above scheme, the second communication device can determine one or more satellite network devices corresponding to the P candidate satellite beams as candidate satellite network devices, and the second communication device can send the fourth information to the candidate satellite network devices, so that after one or more terminal devices located in the first geographic area perform handover through a target satellite beam from the P satellite beams, the target satellite network device after handover can obtain the context information of the terminal devices, to improve service continuity.

[0082] For example, the second communication device can determine P satellite beams from N satellite beams, that is, the P satellite beams can be candidate satellite beams. And the signal coverage area of any satellite beam in the P satellite beams contains the geographical area where the first terminal device currently locates, which can avoid sending the context of the first terminal device and the forwarding data of the first terminal device to a satellite network device corresponding to a satellite beam whose signal coverage area does not contain the geographical area where the first terminal device currently locates as a target satellite beam, thereby reducing signaling overhead.

[0083] In a possible implementation of the second aspect, the method further includes: receiving, by the second communication device, first tunnel information, the first tunnel information being used for receiving data packets of one or more terminal devices located in the first geographical area and forwarded by a source satellite network device corresponding to a source satellite beam; forwarding, by the second communication device, the data packets of the one or more terminal devices located in the first geographical area based on the first tunnel information, and / or sending, by the second communication device, the data packets cached for the one or more terminal devices through the first tunnel information.

[0084] Based on the above scheme, the second communication device can further receive first tunnel information and send data packets associated with the one or more terminal devices located in the first geographical area based on the first tunnel information, so that the receiver of the associated data packets can subsequently transmit the associated data packets after the terminal device switches, thereby improving service continuity.

[0085] Optionally, the fourth information is sent to the one or more satellite network devices corresponding to the P satellite beams through an interface between the source satellite network device corresponding to the source satellite beam and the one or more satellite network devices corresponding to the P satellite beams; or the fourth information is sent to the one or more satellite network devices corresponding to the P satellite beams through a core network device.

[0086] In a possible implementation of the second aspect, the context information of the one or more terminal devices includes second tunnel information allocated by the source satellite network device, the second tunnel information being used for determining a radio bearer and / or a session of the one or more terminal devices corresponding to the received downlink data packets, the radio bearer and / or the session being used for transmitting the downlink data packets of the one or more terminal devices.

[0087] Based on the above scheme, the fourth information sent by the second communication device can include the second tunnel information allocated by the source satellite network device, so that the receiver of the fourth information can determine the radio bearer and / or the session based on the second tunnel information, and transmit the data packets of the terminal device based on the determined radio bearer or session, thereby improving service continuity.

[0088] The third aspect of the present application provides a communication method applied to a third communication device, such as being executed by the third communication device, which can be a communication device (e.g., a target satellite network device), or the third communication device can be a part of the communication device (e.g., a circuit or a chip responsible for communication functions (e.g., a Modem chip, also known as a baseband chip, or a SoC chip or a SIP chip containing a modem core, etc.), or the third communication device can also be a logic module or software capable of realizing all or part of the functions of the communication device.

[0089] In the method, the third communication device receives fourth information including context information of one or more terminal devices located in the first geographical area, the one or more terminal devices including the first terminal device; and the third communication device receives a RACH request message sent by the first terminal device, and the context information of the first terminal device is used to switch the first terminal device to a target satellite beam.

[0090] Based on the above scheme, the third communication device can receive fourth information including context information of one or more terminal devices located in the first geographical area, and after the third communication device receives a RACH request message sent by a first terminal device in the one or more terminal devices, the third communication device can switch the first terminal device to a target satellite beam based on the context information of the first terminal device. Thus, the third communication device can realize the switching of the terminal device based on the context information of the terminal device obtained in advance, which can realize fast switching while avoiding or reducing the occurrence of service discontinuity.

[0091] Optionally, the third communication device receives the fourth information through an interface between a source satellite network device corresponding to the source satellite beam and a target satellite network device corresponding to the target satellite beam.

[0092] Optionally, the third communication device receives the fourth information through a core network device. For example, the second communication device can send a first message including the fourth information and an identifier of the target satellite network device to the core network device, and thereafter, the core network device sends the fourth information to the third communication device based on the first message.

[0093] In a possible implementation manner of the third aspect, the method further includes: the third communication device sends first tunnel information, the first tunnel information being used to receive data packets of one or more terminal devices located in the first geographical area forwarded by the source satellite network device; and the third communication device receives the data packets of the one or more terminal devices located in the first geographical area based on the first tunnel information.

[0094] Based on the above scheme, the third communication device can further send the first tunnel information, so that a first tunnel information receiver (for example, the second communication device) sends data packets associated with one or more terminal devices located in the first geographic area based on the first tunnel information, so that the third communication device can subsequently transmit the associated data packets after terminal device switching to improve service continuity.

[0095] In a possible implementation manner of the third aspect, the method further includes: the third communication device buffering the received data packets of one or more terminal devices located in the first geographic area forwarded by the source satellite network device.

[0096] Based on the above scheme, the third communication device can further buffer the received data packets of one or more terminal devices located in the first geographic area forwarded by the source satellite network device, so that the third communication device can transmit the buffered data packets after the one or more terminal devices switch to the target satellite beam, to improve service continuity.

[0097] Optionally, the buffered data packets include data packets of the first terminal device, and the method further includes: after determining that the first terminal device successfully performs the RACH procedure, the third communication device sends the buffered data packets to the first terminal device.

[0098] Optionally, the data packets of one or more terminal devices located in the first geographic area forwarded by the source satellite network device include data packets of the first terminal device, and the method further includes: after determining that the first terminal device successfully performs the RACH procedure, the third communication device sends the data packets of the first terminal device to the first terminal device.

[0099] In a possible implementation manner of the third aspect, the context information of the first terminal device includes second tunnel information allocated by the source satellite network device, and the method further includes: the third communication device determines a radio bearer or a session for transmitting data packets of the first terminal device according to the second tunnel information and a data packet header forwarded by the source satellite network device.

[0100] Based on the above scheme, the fourth information received by the third communication device can include second tunnel information allocated by the source satellite network device, so that a receiver of the fourth information can determine a radio bearer or a session based on the second tunnel information, and transmit data packets of a terminal device based on the determined radio bearer or session, to improve service continuity.

[0101] In a possible implementation manner of the third aspect, the context information of the one or more terminal devices includes context information of the second terminal device, and the method further includes: starting, by the third communication apparatus, a timer after receiving the context information of the second terminal device, and releasing the context information of the second terminal device if the timer expires and the second terminal device does not access.

[0102] Based on the above scheme, in the case that the timer expires and the second terminal device does not access, the third communication apparatus can determine that the second terminal device will possibly not switch to the third communication apparatus, and therefore, the third communication apparatus can release the context information of the second terminal device to save storage overhead.

[0103] In a possible implementation manner of the third aspect, in the case that the timer expires and the second terminal device does not access, the method further includes: releasing, by the third communication apparatus, the data packet buffered for the second terminal device if the data packet is forwarded from the source satellite network device.

[0104] Based on the above scheme, in the case that the timer expires and the second terminal device does not access, the third communication apparatus can determine that the second terminal device will possibly not switch to the third communication apparatus, and therefore, the third communication apparatus can release the data packet buffered for the second terminal device from the source satellite network device to save storage overhead.

[0105] In a possible implementation manner of the third aspect, the method further includes: sending, by the third communication apparatus, fifth information, where the fifth information indicates tunnel information of a target satellite network device corresponding to the target satellite beam, and the tunnel information of the target satellite network device is used for the target satellite network device to receive forwarded data of the one or more terminal devices.

[0106] Based on the above scheme, the third communication apparatus can send the fifth information indicating the tunnel information of the target satellite network device corresponding to the target satellite beam, so that a receiver of the fifth information sends the forwarded data of the one or more terminal devices based on the tunnel information of the target satellite network device, to facilitate the third communication apparatus to transmit the received forwarded data after the one or more terminal devices switch to the third communication apparatus, thereby improving service continuity.

[0107] The fourth aspect of the present application provides a communication method applied to a fourth communication device, such as being executed by the fourth communication device, which can be a communication device (e.g., a core network device), or the fourth communication device can be a part of the communication device (e.g., a circuit or a chip responsible for communication functions (e.g., a Modem chip, also known as a baseband chip, or a SoC chip or a SIP chip containing a modem core, etc.), or the fourth communication device can also be a logic module or software capable of realizing all or part of the functions of the communication device.

[0108] In the method, the fourth communication device receives a first message from a source satellite network device, the first message comprising fourth information and an identifier of a target satellite network device, the fourth information comprising context information of one or more terminal devices located in a first geographic area; wherein the source satellite network device is a source satellite network device serving the one or more terminal devices; and the fourth communication device sends the fourth information to the target satellite network device.

[0109] Based on the above scheme, after receiving the first message comprising the fourth information and the identifier of the target satellite network device, the fourth communication device can send the fourth information to the target satellite network device, so that the target satellite network device can obtain the context information of the one or more terminal devices located in the first geographic area. In this way, the target satellite network device can subsequently realize the handover of the terminal device based on the context information of the terminal device obtained in advance, which can realize fast handover and also avoid or reduce the occurrence of service discontinuity.

[0110] In a possible implementation form of the fourth aspect, the method further comprises: the fourth communication device receiving fifth information from the target satellite network device, the fifth information indicating tunnel information of the target satellite network device, the tunnel information of the target satellite network device being used by the target satellite network device to receive forwarding data of the one or more terminal devices; and the fourth communication device establishing a tunnel between the target satellite network device corresponding to the target satellite beam and the source satellite network device based on the tunnel information of the target satellite network device.

[0111] Based on the above scheme, the fourth communication device can receive the fifth information indicating the tunnel information of the target satellite network device corresponding to the target satellite beam, so that the fourth communication device establishes a tunnel between the target satellite network device corresponding to the target satellite beam and the source satellite network device based on the tunnel information of the target satellite network device, so that after the one or more terminal devices switch to the target satellite network device, the target satellite network device can transmit the received forwarding data, thereby improving service continuity.

[0112] Optionally, the fourth communication device establishes a tunnel between the target satellite network device corresponding to the target satellite beam and the source satellite network device based on the tunnel information of the target satellite network device, including: the fourth communication device acquires tunnel information of a first network element, the tunnel information of the first network element being used to receive the forwarding data of the one or more terminal devices from the source satellite network device; the fourth communication device sends indication information to the first network element, the indication information being used to instruct the first network element to send the forwarding data of the one or more terminal devices received from the source satellite network device through the tunnel information of the first network element to the target satellite network device through the tunnel information of the target satellite network device.

[0113] The fifth aspect of the present application provides a communication device, which comprises a transceiver unit and a processing unit; the transceiver unit is configured to receive first information, the first information being used to indicate information of N satellite beams; in each time period of K time periods, a signal coverage area of at least one satellite beam in the N satellite beams comprises a first geographic area; wherein the K time periods are continuous time periods with the same length, and K and N are positive integers; when the first information is received, a terminal device located in the first geographic area comprises a first terminal device; the processing unit is configured to determine a target satellite beam for communicating with the first terminal device based on the information of the N satellite beams, the target satellite beam being contained in the N satellite beams.

[0114] In the fifth aspect of the present application, the constituent modules of the communication device can also be configured to perform the steps performed in the various possible implementation manners of the first aspect and achieve the corresponding technical effects, which can be referred to the first aspect for details and will not be described here again.

[0115] The sixth aspect of the present application provides a communication device, which comprises a transceiver unit and a processing unit; the processing unit is configured to acquire first information, the first information being used to indicate information of N satellite beams, in each time period of K time periods, a signal coverage area of at least one satellite beam in the N satellite beams comprises a first geographic area; wherein the K time periods are continuous time periods with the same length, and K and N are positive integers; when the first information is received, a terminal device located in the first geographic area comprises a first terminal device; the information of the N satellite beams is used to determine a target satellite beam for communicating with the first terminal device, the target satellite beam being contained in the N satellite beams; the transceiver unit is configured to send the first information.

[0116] In the sixth aspect of the present application, the constituent modules of the communication device can also be configured to perform the steps performed in the various possible implementation manners of the second aspect and achieve the corresponding technical effects, which can be referred to the second aspect for details and will not be described here again.

[0117] The seventh aspect of the present application provides a communication device, comprising a transceiver; the transceiver is configured to receive fourth information, the fourth information comprising context information of one or more terminal devices located in a first geographical area, the one or more terminal devices comprising a first terminal device; the transceiver is further configured to receive a RACH request message sent by the first terminal device, and the context information of the first terminal device is used to switch the first terminal device to a target satellite beam.

[0118] In the seventh aspect of the present application, the component modules of the communication device can also be configured to perform the steps performed in the various possible implementation manners of the third aspect and achieve the corresponding technical effects, which can be referred to the third aspect for details and will not be described here.

[0119] The eighth aspect of the present application provides a communication device, comprising a transceiver, the transceiver is configured to receive a first message from a source satellite network device, the first message comprising fourth information and an identifier of a target satellite network device, the fourth information comprising context information of one or more terminal devices located in a first geographical area; wherein the source satellite network device is a source satellite network device serving the one or more terminal devices; the transceiver is further configured to send the fourth information to the target satellite network device.

[0120] In the eighth aspect of the present application, the component modules of the communication device can also be configured to perform the steps performed in the various possible implementation manners of the fourth aspect and achieve the corresponding technical effects, which can be referred to the fourth aspect for details and will not be described here.

[0121] The ninth aspect of the present application provides a communication device, comprising at least one processor, the at least one processor is configured to execute computer programs or instructions to enable the device to implement the method of any one of the first aspect to the fourth aspect and any one of the possible implementation manners thereof.

[0122] Optionally, the at least one memory is coupled with the memory, and the memory is configured to store the computer programs or instructions.

[0123] Optionally, the communication device comprises the memory.

[0124] The tenth aspect of the present application provides a communication device, comprising at least one logic circuit and an input-output interface; the logic circuit is configured to execute the method as described in any one of the possible implementation manners of any one of the first aspect to the fourth aspect.

[0125] The eleventh aspect of the present application provides a communication system, comprising the first communication device and the second communication device.

[0126] Optionally, the communication system further comprises the third communication device and / or the fourth communication device.

[0127] The twelfth aspect of the present application provides a computer readable storage medium, which is used to store one or more computer execution instructions, when the computer execution instructions are executed by a processor, the processor executes the method in any possible implementation manner of any one of the first aspect to the fourth aspect.

[0128] The thirteenth aspect of the present application provides a computer program product (or computer program), when the computer program in the computer program product is executed by the processor, the processor executes the method in any possible implementation manner of any one of the first aspect to the fourth aspect.

[0129] The fourteenth aspect of the present application provides a chip or chip system, which comprises at least one processor, and is used to support a communication device to implement the method in any possible implementation manner of any one of the first aspect to the fourth aspect. For example, the chip can be a baseband chip, a modem chip, a system on chip (SoC) chip containing a modem core, a system in package (SIP) chip, or a communication module, etc.

[0130] In a possible design, the chip or chip system can further comprise a memory, which is used to store necessary program instructions and data of the communication device. The chip system can be composed of a chip, or can comprise a chip and other discrete devices. Optionally, the chip system further comprises an interface circuit, which provides program instructions and / or data for the at least one processor.

[0131] The technical effects brought by the fifth aspect to the fourteenth aspect can be referred to the technical effects brought by the first aspect to the fourth aspect, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0132] FIG. 1 is a schematic diagram of a communication system provided by the present application;

[0133] FIGS. 2a to 2e are some schematic diagrams of a satellite communication process provided by the present application;

[0134] FIGS. 3a to 3c are some schematic diagrams of a satellite communication process provided by the present application;

[0135] FIG. 4 is a schematic diagram of a satellite communication process in a 5G system provided by the present application;

[0136] FIGS. 5 and 6 are some schematic diagrams of a communication method provided by the present application;

[0137] FIG. 7a to FIG. 7d are some schematic diagrams of the communication method provided by the present application;

[0138] FIG. 8 to FIG. 11 are some schematic diagrams of the communication device provided by the present application. DETAILED DESCRIPTION

[0139] First, some terms in the embodiments of the present application are explained to facilitate the understanding of those skilled in the art.

[0140] (1) Terminal device: can be a wireless terminal device capable of receiving network device scheduling and indication information, the wireless terminal device can be a device that provides voice and / or data connectivity to a user, or a handheld device with wireless connection function, or other processing devices connected to a wireless modem.

[0141] The terminal device can be various communication kits (a kit can include, for example, an antenna, a power supply template, a cable, and a Wi-Fi module, etc.) with wireless communication functions, and can also be a communication module with satellite communication functions, a satellite phone or its components, a very small aperture terminal (VSAT). The terminal device can be a mobile terminal device, such as a mobile phone (or called "cellular" phone, mobile phone), a computer and a data card, for example, it can be a portable, pocket-sized, handheld, built-in computer or vehicle-mounted mobile device that exchanges voice and / or data with a wireless access network. For example, personal communication service (PCS) phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), tablets (Pads), computers with wireless transceiver functions, etc. The wireless terminal device can also be referred to as a system, a subscriber unit, a subscriber station, a mobile station, a mobile station (MS), a remote station, an access point (AP), a remote terminal, an access terminal, a user terminal, a user agent, a subscriber station (SS), customer premises equipment (CPE), a terminal, user equipment (UE), a mobile terminal (MT), a drone, etc. The terminal device can also be a wearable device and a next-generation communication system, for example, a terminal device in a 6G communication system or a terminal device in a future evolved public land mobile network (PLMN), etc. Of course, the terminal device in this application can also refer to a chip, a modem, a system on a chip (SoC) mainly responsible for relevant communication functions in the device, or a communication platform that can include a radio frequency (RF) part, etc.

[0142] (2) Network device: can be a device in a wireless network, for example, the network device can be a RAN node (or device) for accessing a terminal device to a wireless network, which can also be referred to as a base station. At present, some examples of RAN devices are: base station (base station), evolved NodeB (eNodeB), base station gNB (gNodeB) in 5G communication system, transmission reception point (transmission reception point, TRP), evolved Node B (eNB), radio network controller (radio network controller, RNC), Node B (Node B, NB), home base station (for example, home evolved Node B, or home Node B, HNB), baseband unit (baseband unit, BBU), or wireless fidelity (wireless fidelity, Wi-Fi) access point AP, etc. In addition, in a network structure, the network device can include a centralized unit (centralized unit, CU) node, or a distributed unit (distributed unit, DU) node, or a RAN device including a CU node and a DU node.

[0143] Optionally, the RAN node can also be a macro base station, a micro base station or an indoor station, a relay node or a donor node, or a wireless controller in a cloud radio access network (cloud radio access network, CRAN) scenario. The RAN node can also be a server, a wearable device, a vehicle or a vehicle-mounted device, etc. For example, the access network device in vehicle to everything (vehicle to everything, V2X) technology can be a road side unit (road side unit, RSU).

[0144] In another possible scenario, a terminal is assisted by multiple RAN nodes to implement wireless access, and different RAN nodes respectively implement part of functions of a base station. For example, a RAN node can be a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU), etc. The CU and the DU can be separately arranged, or can also be included in the same network element, for example, in a baseband unit (BBU). The RU can be included in a radio frequency device or a radio frequency unit, for example, included in a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0145] In different systems, the CU (or CU-CP and CU-UP), DU or RU can also have different names, but those skilled in the art can understand their meanings. For example, in an open RAN (O-RAN or ORAN) system, the CU can also be referred to as an O-CU (open CU), the DU can also be referred to as an O-DU, the CU-CP can also be referred to as an O-CU-CP, the CU-UP can also be referred to as an O-CU-UP, and the RU can also be referred to as an O-RU. For the convenience of description, the CU, CU-CP, CU-UP, DU and RU are taken as examples for description in this application. Any one of the CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0146] The communication between the access network device and the terminal device follows a certain protocol layer structure. The protocol layer can include a control plane protocol layer and a user plane protocol layer. The control plane protocol layer can include at least one of a radio resource control (RRC) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, a media access control (MAC) layer, or a physical (PHY) layer, etc. The user plane protocol layer can include at least one of a service data adaptation protocol (SDAP) layer, a PDCP layer, an RLC layer, a MAC layer, or a physical layer, etc.

[0147] For the correspondence between the network elements in the ORAN system and the protocol layer functions that can be implemented by the network elements, refer to Table 1 below.

[0148] Table 1

[0149] The network device can be another device that provides a wireless communication function for the terminal device. The embodiments of the present application do not limit the specific technology and specific device form adopted by the network device. For the convenience of description, the embodiments of the present application do not limit.

[0150] The network device can also include a core network device, which can include, for example, a mobility management entity (MME) in a fourth generation (4G) network, a home subscriber server (HSS), a serving gateway (S-GW), a policy and charging rules function (PCRF), a public data network gateway (P-GW), an access and mobility management function (AMF) in a 5G network, a user plane function (UPF), a session management function (SMF), and other network elements. In addition, the core network device can also include other core network devices in a 5G network and a next-generation network of the 5G network.

[0151] In the embodiments of the present application, the network device can also be a network node with artificial intelligence (AI) capability, which can provide AI services for terminals or other network devices, for example, AI nodes, computing power nodes, AI-capable RAN nodes, AI-capable core network elements, etc. on the network side (access network or core network).

[0152] In the embodiments of the present application, the device for implementing the function of the network device can be a network device or a device capable of supporting the network device to implement the function, such as a chip system, which can be installed in the network device. In the technical solutions provided in the embodiments of the present application, the device for implementing the function of the network device is taken as an example to describe the technical solutions provided in the embodiments of the present application.

[0153] In the embodiments of the present application, the network device can be deployed on a satellite or on the ground. For example, a base station can be deployed entirely on a satellite, or part of the functions of the base station can be deployed on a satellite, for example, the radio frequency part (RU) of the base station can be deployed on a satellite, and other parts can be deployed on the ground. For another example, the RU and DU of the base station can be deployed on a satellite, and the CU can be deployed on the ground. Similarly, the core network device can also be deployed on a satellite. For example, part of the user plane network elements of the core network can be deployed on a satellite to support direct interaction between terminals through a satellite, and the communication does not fall to the ground. Part of the control plane network elements of the core network can also be deployed on a satellite, for example, the mobility management network element and the session management network element can be deployed on a satellite to support emergency rescue services in disaster scenarios without ground networks.

[0154] (3) Configuration and pre-configuration: In the present application, configuration and pre-configuration will be used together. Configuration refers to that the network device sends some parameter configuration information or parameter values to the terminal device or the network device through messages or signaling, so that the terminal device or the network device determines the communication parameters or the resources in the transmission according to the values or information. Pre-configuration is similar to configuration, which can be parameter information or parameter values agreed by the network device and the terminal device in advance, or parameter information or parameter values adopted by the network device or the terminal device according to the standard protocol, or parameter information or parameter values pre-stored in the network device or the terminal device. The present application does not limit this.

[0155] Further, these values and parameters can be changed or updated.

[0156] (4) The terms "system" and "network" in the embodiments of the present application can be used interchangeably. "At least one" refers to one or more, and "multiple" refers to two or more. The "and / or" describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the cases of A alone, A and B together, and B alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or multiple items. For example, "at least one of A, B, and C" includes A, B, C, AB, AC, BC, or ABC. In addition, unless otherwise specified, the ordinal numbers "first", "second", etc. mentioned in the embodiments of the present application are used to distinguish a plurality of objects, and are not used to limit the order, time sequence, priority or importance of the plurality of objects.

[0157] (5) In the embodiments of the present application, "sending" and "receiving" represent the direction of signal transmission. For example, "sending information to XX" can be understood as that the destination of the information is XX, which can include direct sending through an air interface or a network interface, or indirect sending through other units or modules. "Receiving information from YY" can be understood as that the source of the information is YY, which can include direct receiving from YY through an air interface or a network interface, or indirect receiving from YY through other units or modules. "Sending" can also be understood as "output" of a chip interface, and "receiving" can also be understood as "input" of a chip interface.

[0158] In other words, sending and receiving can be carried out between devices through a direct interface, for example, between network devices and terminal devices, between network devices, or within a device, for example, between components, modules, chips, software modules or hardware modules within a device through a bus, wire or interface. Sending and receiving can also be indirectly carried out between devices through intermediate devices, for example,

[0159] It can be understood that the information between the source and the destination of the information transmission can be processed as necessary, such as encoding, modulation, etc., but the destination can understand the valid information from the source. Similar expressions in the present application can be understood similarly, and will not be repeated here.

[0160] (6) Geographic area. In the embodiments of the present application, the geographic area can be replaced by area, ground area, etc. Among them, the area is fixed relative to the earth, or understood as the area refers to the geographic area fixed relative to the earth.

[0161] Exemplarily, a region can have at least one of the following properties: shape, contour, size, radius, area, geographical position, etc. In addition, a region can also have a height property, i.e., a region can be understood as a geographical region at a given height or a range of heights. For example, a region can refer to a geographical region at an altitude of 0 km or within a range of 0 km plus or minus 2 km, or a geographical region at an average altitude, or a geographical region at a specific height, e.g., a geographical region at an altitude of 10 km or within a range of 10 km plus or minus 3 km.

[0162] Alternatively, the above region fixed relative to the earth can also be referred to as a "wave position", "geographical region", "beam coverage region", "ground fixed cell", "ground fixed wave position", etc. Of course, there can be other names, and the name of the region fixed relative to the earth is not specifically limited in this application.

[0163] In a possible implementation, the shapes, contours, sizes, radii, and areas of different regions can or can not be the same. The geographical positions of different regions are different. There can or can not be overlap between different regions.

[0164] In a possible implementation, a region is fixed relative to the earth, which can be understood as: the contour, size, or geographical position of the region does not change, e.g., the contour, size, or geographical position of the region does not change with time. Alternatively, a region is fixed relative to the earth, which can be understood as: the contour of the region and the points in the region can be described by a fixed coordinate system on the earth, or the coordinates of each point on the contour of the region in the fixed coordinate system on the earth are fixed and do not change.

[0165] In a possible implementation, the shape of a region can be a regular hexagon, or other shapes such as a regular pentagon, a circle, an ellipse, etc. Alternatively, the shape of a region can also be irregular, which is not limited.

[0166] Exemplarily, the shape of a region can be defined by a protocol or defined by a network device. The shapes of regions defined by different network devices can or can not be the same. A same network device can also define multiple shapes of regions. Similarly, the size, radius, and area of a region can also be defined by a protocol or defined by a network device. The sizes, radii, and areas of regions defined by different network devices can or can not be the same. A same network device can also define multiple sizes of regions, multiple radii of regions, or multiple areas of regions.

[0167] In a possible implementation, the earth surface can be divided into multiple regions, and the multiple regions can be indexed (e.g., numbered). The terminal device and the network device can agree on the numbering manner of the regions (e.g., whether to start from 1 or from 0) and the correspondence between the regions and the indexes. Alternatively, a protocol can define the numbering manner of the regions and the correspondence between the regions and the indexes. Based on the index of a region, the geographical position and other information of the region can be determined.

[0168] Optionally, the multiple divided regions can completely cover the earth surface, for example, any position on the earth surface belongs to a region; or the multiple divided regions can cover part of the geographical positions on the earth, for example, the multiple regions can not cover the south and / or north poles of the earth, that is, the south and / or north poles can not exist in the regions.

[0169] Optionally, the manner of dividing the multiple regions can be defined by a protocol or can be defined by the network device. The dividing manners defined by different network devices can be the same or different. The same network device can also define multiple dividing manners.

[0170] As a first possible dividing manner, a granularity of latitude and longitude grid can be used to divide the earth surface, for example, the earth surface can be divided by latitude and longitude grid with a granularity of 1 degree. If only this discrete manner is used, the global can be divided into 360x360=129600 regions, and the terminal device and the network device can agree that the indexes of the 129600 regions are 0, 1, …, 129599, or can also be agreed as 1, 2, …, 129600.

[0171] Optionally, when the height attribute of the geographical region is introduced, multiple grids dividing the earth surface can be defined, for example, the grid with an altitude of 0 km or within the range of 0 km plus or minus 2 km can be divided by latitude and longitude grid with a granularity of 1 degree, resulting in 129600 regions. The position with an altitude of 10 km or within the range of 10 km plus or minus 3 km is further divided by latitude and longitude grid with a granularity of 1 degree, resulting in another 129600 regions. When indexing these grids, the index range of the single-layer grid needs to be extended, for example, the total index is 0, 1, …, 129599, 129600, 129601, …, 259199, where the first 129600 serial numbers represent the index of the grid with an altitude of 0 km, and the last 129600 serial numbers represent the index of the grid with an altitude of 10 km.

[0172] For example, in the case of a network device being a LEO satellite, a relatively small granularity can be used for discretization; in the case of a network device being a GEO satellite, a relatively large granularity can be used for discretization.

[0173] As a second possible division manner, the earth surface can be divided using latitude and longitude grids of various granularities, for example, the earth surface in a part of the earth or a part of administrative region is divided using latitude and longitude grids of 1 degree granularity, and the earth surface in another part of the earth or another part of administrative region is divided using latitude and longitude grids of 2 degree granularity.

[0174] Alternatively, after introducing the height attribute of the geographical region, the earth surface at an altitude of 0 km can be divided using latitude and longitude grids of 1 degree granularity, and the earth surface at an altitude of 10 km can be divided using latitude and longitude grids of 2 degree granularity.

[0175] As a third possible division manner, the earth surface can be divided according to administrative regions. For example, a township-level administrative region is taken as a region.

[0176] As a fourth possible division manner, for a GEO satellite, a projection of a beam of the GEO satellite on the ground can be taken as a region. Since the GEO satellite is stationary relative to the earth, the projection of the beam of the GEO satellite on the ground can be considered as fixed relative to the earth.

[0177] In actual applications, the earth surface can be divided in combination of multiple division manners, for example, the earth surface in a part of the earth or a part of administrative region is divided using latitude and longitude grids of 1 degree granularity, and the earth surface in another part of the earth or another part of administrative region is divided according to administrative regions.

[0178] In a possible implementation, in the case where the earth surface is divided into multiple regions, the same earth surface range can be divided into regions of different levels. For example, for a certain earth surface range, the first level of region division is performed using latitude and longitude grids of 10 degree granularity, the second level of region division is performed using latitude and longitude grids of 6 degree granularity, and the third level of region division is performed using latitude and longitude grids of 1 degree granularity. In this case, in the earth surface range, the number of regions of the first level is greater than the number of regions of the second level, and the number of regions of the second level is greater than the number of regions of the third level. In addition, in this scenario, the regions of each level can be numbered separately.

[0179] (7) In the embodiments of the present application, the indication can include direct indication and indirect indication, and can also include explicit indication and implicit indication. The information indicated by certain information (indication information described below) is referred to as to-be-indicated information. In the implementation process, there are many ways to indicate the to-be-indicated information, for example, but not limited to, the to-be-indicated information can be directly indicated, such as the to-be-indicated information itself or an index of the to-be-indicated information. The to-be-indicated information can also be indirectly indicated by indicating other information, where the other information and the to-be-indicated information have an association relationship. The to-be-indicated information can also be indicated only by a part of the to-be-indicated information, and the other part of the to-be-indicated information is known or agreed in advance. For example, the indication of a specific information can be achieved by means of the arrangement order of each information agreed in advance (for example, protocol predefined), thereby reducing the indication overhead to a certain extent. The specific manner of indication is not limited in the present application. It can be understood that the indication information can be used to indicate the to-be-indicated information for the sender of the indication information, and the indication information can be used to determine the to-be-indicated information for the receiver of the indication information.

[0180] In the present application, the same or similar parts between various embodiments can be mutually referred to, unless otherwise specified. In the various embodiments of the present application, and the various methods / designs / implementation manners in the various embodiments, the terms and / or descriptions of different embodiments, and the various methods / designs / implementation manners in the various embodiments are consistent and can be mutually referred to, unless otherwise specified and logically conflicted. The technical features of different embodiments, and the various methods / designs / implementation manners in the various embodiments can be combined to form new embodiments, methods, or implementation manners according to their inherent logical relationship. The implementation manners of the present application described below do not constitute a limitation on the protection scope of the present application.

[0181] Referring to FIG. 1, there is shown a schematic diagram of an architecture of a communication system 10 to which embodiments of the present application are applied. As shown in FIG. 1, the communication system 10 includes a radio access network (RAN) 100 and a core network 200. Optionally, the communication system 10 can further include an Internet 300. The RAN 100 includes at least one RAN node (e.g., 110a and 110b in FIG. 1, collectively referred to as 110) and at least one terminal (e.g., 120a-120j in FIG. 1, collectively referred to as 120). The RAN 100 can further include other RAN nodes, such as a wireless relay device and / or a wireless backhaul device (not shown in FIG. 1). The terminals 120 are wirelessly connected to the RAN nodes 110, and the RAN nodes 110 are connected to the core network 200 wirelessly or via wire. The core network devices in the core network 200 and the RAN nodes 110 in the RAN 100 can be independent and different physical devices, or can be the same physical device integrated with the logical functions of the core network devices and the logical functions of the RAN nodes. The terminals and the terminals, and the RAN nodes and the RAN nodes can be connected to each other via wire or wirelessly.

[0182] It should be noted that the technical solutions of the embodiments of the present application are applicable to a terrestrial communication system. Alternatively, the technical solutions of the embodiments of the present application are applicable to a communication system integrating terrestrial communication and satellite communication, which can also be referred to as a non-terrestrial network (NTN) communication system. For example, the RAN 100 in FIG. 1 can include a terrestrial base station, where the terrestrial base station can include a TN cell (i.e., the signals of the TN cell can be transmitted and received by the terrestrial base station); and the RAN 100 in FIG. 1 can further include a non-terrestrial base station, for example, a satellite, which can include an NTN cell (i.e., the signals of the NTN cell can be transmitted and received by the satellite). The terrestrial communication system can be, for example, a long term evolution (LTE) system, a universal mobile telecommunication system (UMTS), a 5G communication system, a new radio (NR) system, or a next-generation communication system of the 5G communication system, etc., which is not limited herein.

[0183] Satellite communication has wider coverage, communication cost is independent of transmission distance, and can overcome natural geographical obstacles such as oceans, deserts, and mountains, compared with traditional mobile communication systems. In order to overcome the shortcomings of traditional communication networks, satellite communication can be an effective supplement to traditional networks. It is generally believed that, compared with ground network communication, non-ground network communication has different channel characteristics, such as large transmission delay and large Doppler frequency offset. For example, the round-trip delay of GEO satellite communication is 238-270 milliseconds (ms). The round-trip delay of LEO satellite communication is 8-20 ms. According to the orbital height, satellite communication systems can be divided into three types: high-orbit (geostationary earth orbit, GEO) satellite communication systems, also known as synchronous orbit satellite systems; medium-orbit (medium earth orbit, MEO) satellite communication systems; and low-orbit (low earth orbit, LEO) satellite communication systems.

[0184] The GEO satellite is also commonly known as a geostationary satellite, and the orbital height can be 35,786 kilometers (km). The main advantage is that it is relatively stationary relative to the ground and provides a large coverage area. However, the GEO satellite also has relatively prominent disadvantages: the distance from the earth is too large, requiring a large-diameter antenna; the transmission delay is large, about 0.5 seconds, which cannot meet the needs of real-time services; and the orbital resources are relatively scarce, the launch cost is high, and coverage cannot be provided for polar regions. The MEO satellite has an orbital height of 2,000-35,786 km, and a relatively small number of satellites can achieve global coverage, but the transmission delay is higher than that of the LEO satellite. It is mainly used for positioning and navigation. In addition, the orbital height of 300-2,000 km is called a low-orbit satellite (LEO). The LEO satellite has a lower orbital height than the MEO and GEO satellites, smaller data propagation delay, less power loss, and relatively lower launch cost. Therefore, the LEO satellite communication network has made great progress in recent years and has attracted attention.

[0185] In one possible implementation, the satellite device can be divided into a transparent mode and a regenerative mode according to the working mode.

[0186] The two modes will be described below by way of example with reference to the implementation modes shown in FIGS. 2a, 2b, 2c, and 2d.

[0187] In the implementation mode of the transparent mode as shown in FIG. 2a, the satellite and the gateway (i.e., the NTN Gateway in FIG. 2a) act as a relay, that is, the Remote Radio Unit shown in FIG. 2a, and the communication between the terminal device and the gNB needs to be realized through the relay process. In other words, in the transparent mode, the satellite has the function of relay forwarding.

[0188] For example, in the implementation mode of the transparent mode as shown in FIG. 2b, when the satellite (including GEO satellite, MEO satellite, LEO satellite, etc.) works in the transparent mode, the satellite has the function of relay forwarding. The gateway (or gateway station) has the function of the base station or part of the base station function, at this time, the gateway can be regarded as the base station. Alternatively, the base station can be deployed separately from the gateway, and then the time delay of the feeder link includes the time delay of the satellite to the gateway and the time delay of the gateway to the gNB.

[0189] Optionally, the transparent mode can be taken as an example that the gateway and the gNB are together or close to each other, and for the case that the gateway is far away from the gNB, the time delay of the feeder link can be the sum of the time delay of the satellite to the gateway and the time delay of the gateway to the gNB.

[0190] In the implementation mode of the regenerative mode as shown in FIG. 2c, the satellite and the gateway (i.e., the NTN Gateway in FIG. 2c) act as the gNB and can communicate with the terminal device. In other words, in the regenerative mode, the satellite has the function of the base station or part of the base station function, at this time, the satellite can be regarded as the base station.

[0191] For example, in the implementation mode of the regenerative mode as shown in FIG. 2d, when the satellite (including GEO satellite, MEO satellite, LEO satellite, etc.) works in the regenerative mode, compared with the implementation mode shown in FIG. 2b, the satellite has the function of the base station or part of the base station function, at this time, the satellite can be regarded as the base station (i.e., the air base station).

[0192] Optionally, in FIG. 2b and / or FIG. 2d, the satellite can be realized by other means, such as the unmanned aerial vehicle or the high-altitude platform in the figure.

[0193] It should be noted that the base stations of the NTN and the ground network can be interconnected through a common core network, and the NTN and the ground base station can access different core networks and be interconnected through the interface between the core networks.

[0194] In addition, as a network device, the related information of the running track of the satellite can be determined based on the ephemeris information. As an example, the ephemeris information can include one or more information in Table 2.

[0195] Table 2

[0196] It should be noted that in actual applications, the last parameter in Table 2, the near-Earth time t p may be replaced by a true anomaly or a mean anomaly, which have the same effect, as shown in Table 3.

[0197] Table 3

[0198] In a possible implementation, the satellite can work in an earth-fixed system, or a quasi-earth fixed system or a satellite-fixed system, wherein the earth-fixed system or the quasi-earth fixed system can also be referred to as a gaze system, and the satellite-fixed system can also be referred to as a non-gaze system.

[0199] As an example, in the non-gaze system shown in FIG. 2e, the satellite beam coverage range moves with the satellite in a continuous time period (time T1, T2 and T3 belong to the continuous time period); in the gaze system shown in FIG. 2e, the satellite dynamically adjusts the beam pointing in a continuous time period (time T1, T2 and T3 belong to the continuous time period), so that the beam approximately covers the same region on the ground.

[0200] The implementation of the gaze system will be exemplarily described below with reference to FIGS. 3a to 3c.

[0201] In the gaze system, in any predetermined time period, a geographic region is covered by one or more satellite beams. A satellite cell can be a signal coverage area of one satellite beam, or can be composed of signal coverage areas of multiple satellite beams, i.e., a ground cell can be a ground fixed cell. In any predetermined time period, a terminal device resides in a satellite beam covering a position corresponding to the terminal device. In the next time period, with the movement of the satellite, the satellite beam covering a certain geographic region can change, i.e., the satellite beam covering the geographic region will change from a source satellite beam to a target satellite beam. The source satellite beam and the target satellite beam can belong to the same satellite, or can belong to different satellites.

[0202] As an example, in the gaze system, the signal coverage area of the same satellite beam is different in different time periods. As shown in FIG. 3a, the satellite beam covers geographic region 1 in time period 1, and covers geographic region 2 in time period 2. The time period 1 and the time period 2 can be continuous time periods with the same length, and the geographic region 1 and the geographic region 2 can have an overlapping part or can have no overlapping part, and the example in the figure is that the two geographic regions have no overlapping part.

[0203] In addition, from the perspective of ground coverage, there are two cases as follows.

[0204] Case 1: The coverage of the satellite on the ground is fixed.

[0205] For example, fixed cells can be divided on the ground, and the ground cells are covered by different satellite beams in different time periods, in other words, the range of each ground cell can be one or more geographical areas covered by the signal coverage of a satellite beam.

[0206] As shown in FIG. 3b, for a certain geographical area (i.e., a ground cell), in time period 1 (i.e., a time period with a starting time t1 and an ending time t2), it is covered by satellite beam 2, that is, the signal of the ground cell is transmitted through satellite beam 2; in time period 2 (i.e., a time period with a starting time t2 and an ending time t3), it is covered by satellite beam 1, that is, the signal of the ground cell is transmitted through satellite beam 1.

[0207] Optionally, in the implementation mode shown in FIG. 3b, the coverage areas of satellite beam 1 and satellite beam 2 in two adjacent time periods overlap, that is, both can completely cover the same geographical area, where t2-t1=t3-t2=△t, and △t is the duration of one satellite beam covering one ground cell, such as 15 seconds.

[0208] Optionally, in the above case 1, the beam covering the ground cell can be transmitted through one satellite beam, that is, the coverage of one satellite beam matches the size of the ground cell; in other implementation modes, the signal covering the ground fixed cell can also be transmitted through one satellite, that is, one ground fixed cell matches the coverage of one satellite, and in this case, the ground fixed cell can be covered by multiple beams.

[0209] Case 2: The coverage of the satellite on the ground is not fixed.

[0210] For example, in case 2, although it is a steerable beam, it can not be possible to divide the ground fixed cells, because after the satellite moves, in the next time period, the coverage of the next beam can not exactly match the coverage range of the previous beam.

[0211] As shown in FIG. 3c, a geographical area is covered by beam 1 in time period 1 (i.e., a time period with a starting time t1 and an ending time t2), and is covered by beams 2, 3 and 4 in time period 2 (i.e., a time period with a starting time t2 and an ending time t3). That is, in time period 2, there can be no satellite beam that exactly covers the area covered by the previous beam in the previous time period.

[0212] The present application can be applied to a long term evolution (LTE) system, a new radio (NR) system, a new radio vehicle to everything (NR V2X) system, or a future communication system; can also be applied to a system in which LTE and 5G are hybrid networked; or a device-to-device (D2D) communication system, a machine to machine (M2M) communication system, an Internet of Things (IoT), or a drone communication system; or a communication system supporting multiple wireless technologies such as LTE technology and NR technology; or a non-ground communication system such as a satellite communication system or a high-altitude communication platform. In addition, the communication system can also be applied to a narrow band-internet of things (NB-IoT) system or other communication systems, wherein the communication system includes a network device and a terminal device, the network device serves as a configuration information sending entity, and the terminal device serves as a configuration information receiving entity. In addition, the present application can be applied to a terminal device in RRC_INACTIVE state or a terminal device in RRC_INACTIVE or RRC_IDLE state.

[0213] Optionally, the NR system can also have other names, such as 5G, 5G NR, etc.

[0214] As shown in FIG. 4, taking 5G as an example, a schematic diagram of a 5G regenerative satellite communication system architecture is shown. A ground terminal device accesses a 5G new air interface network, a 5G base station is deployed on a satellite, and is connected to a ground core network through a feeder link. At the same time, there can be an inter-satellite link between satellites to complete signaling interaction and user data transmission between base stations. The devices and interfaces in FIG. 4 are described as follows:

[0215] 5G core network: user access control, mobility management, session management, user security authentication, charging, and other services. It is composed of multiple functional units and can be divided into control plane and data plane functional entities. An access and mobility management unit (AMF) is responsible for user access management, security authentication, and mobility management. A user plane unit (UPF) is responsible for managing user plane data transmission, traffic statistics, and other functions. A session management function (SMF) is mainly used for session management in a mobile network, such as session establishment, modification, and release.

[0216] Ground station: Responsible for forwarding signaling and service data between satellite base stations and the 5G core network.

[0217] 5G New Radio: The wireless link between a terminal and a base station.

[0218] Xn interface: The interface between 5G base stations, mainly used for signaling interactions such as handover.

[0219] NG interface: The interface between 5G base stations and 5G core networks, mainly used for exchanging non-access stratum (NAS) signaling of the core network and user service data.

[0220] Furthermore, network devices in terrestrial network communication systems and satellites in NTN communication systems can be uniformly considered as network devices. The apparatus used to implement the functions of a network device can be a network device itself; it can also be an apparatus capable of supporting the network device in implementing that function, such as a chip system, which can be installed within the network device. In the following description of the technical solutions provided by the embodiments of this application, the apparatus for implementing the functions of a network device deployed on a satellite is used as an example to describe the technical solutions provided by the embodiments of this application. It is understood that when the method provided by the embodiments of this application is applied to a terrestrial network communication system, the actions performed by the satellite can be applied to the base station or network device for execution.

[0221] In this application embodiment, the device for implementing the functions of the terminal device can be the terminal device itself; it can also be a device capable of supporting the terminal device in implementing the functions, such as a chip system, which can be installed in the terminal device. In this application embodiment, the chip system can be composed of chips, or it can include chips and other discrete devices. In the technical solutions provided in this application embodiment, the device for implementing the functions of the terminal device is a terminal or UE as an example to describe the technical solutions provided in this application embodiment.

[0222] In addition, the aforementioned satellites can be geostationary satellites, non-geostationary satellites, artificial satellites, low-Earth orbit satellites, medium-Earth orbit satellites, and high-Earth orbit satellites, etc., which are not specifically limited here.

[0223] The foregoing has described various wireless communication scenarios involved in this application. It should be understood that the above content is merely an illustrative description of the scenarios in which this application can be applied, and this application can also be applied to other application scenarios, which are not limited here. The following will describe the wireless communication process that may be involved in this application.

[0224] In a wireless communication process, mobility management is an important feature that can be used to manage the movement and / or handover of a terminal device (e.g., a UE) between different network nodes. Generally, mobility management includes cell handover and cell reselection, which will be described below through some examples.

[0225] ① Cell handover process.

[0226] Generally, the handover procedure of a terrestrial network mainly includes the following steps:

[0227] 1. Cell handover measurement: the network device (e.g., a base station) usually sends a plurality of measurement configurations corresponding to cells (including a serving cell and neighboring cells) to a terminal device (e.g., a UE), and the UE measures the signal quality (e.g., received signal strength indication (RSSI), reference signal received power (RSRP), reference signal received quality (RSRQ), etc.) of the cells according to the measurement configurations;

[0228] 2. Measurement result reporting: the UE reports the measurement results to the base station, which can be reported periodically or triggered by an event. In the event-triggered reporting, the reporting condition is usually configured as the signal quality of the serving cell being less than a threshold 1 and / or the signal quality of the neighboring cell being greater than a threshold 2.

[0229] 3. Handover decision: the base station selects a suitable target cell according to the reported results, and interacts with the base station where the target cell is located to exchange context information, admission control, and reserved resources related to user handover.

[0230] 4. Handover execution: the UE receives control information related to handover from the serving cell and completes the access procedure in the target cell. The handover execution process can include a RACH procedure.

[0231] It can be understood that the UE can send a RACH request message during the handover execution process. The RACH procedure includes the interaction process of the RACH request message.

[0232] For example, the RACH request message can be a message 1 (MSG 1) or a message A (MSG A).

[0233] Optionally, the cell handover process can be applied to a terminal device in RRC_CONNECTED.

[0234] ② Cell reselection process. After cell reselection, the terminal resides in a new cell.

[0235] Generally, the network device (taking the network device as a base station as an example) usually issues the parameters related to the neighboring cells to the terminal device (taking the terminal device as a UE as an example) in the form of broadcast, and the UE measures the signals of the neighboring cells according to the parameters of the neighboring cells, and compares the measurement values (such as RSRP and / or RSRQ, etc.) and the configured (or pre-configured) parameters (such as the reselection threshold, etc.), and autonomously reselects to the target cell when the conditions are met.

[0236] Optionally, the cell reselection process can be applied to the terminal device in RRC_IDLE or RRC_INACTIVE.

[0237] After the terminal device selects the target cell, if the terminal device does not need to send signaling (such as the mobility registration process) or data, the terminal device camps on the target cell. The terminal device camping on the target cell means that the terminal device maintains downlink synchronization with the target cell, the terminal device reads the broadcast information of the target cell, and monitors the paging message, etc.

[0238] In the communication system shown in FIG. 1 / FIG. 2a / FIG. 2b / FIG. 2c / FIG. 2d / FIG. 2e / FIG. 4, the traditional network device can be a device fixed on the ground, for example, a ground base station belonging to a terrestrial network (TN) cell. With the development of communication technology, the network device can be deployed on a non-ground platform, including but not limited to a low earth orbit satellite, a medium earth orbit satellite, and a high earth orbit satellite, a high-altitude platform, a drone, etc. On some high-altitude platforms, the network device moves relatively quickly on the ground, for example, when the network device is deployed on a low earth orbit satellite.

[0239] Unlike the ground base station belonging to the TN cell, since the satellite base station belonging to the NTN cell can exist at a high speed, it is possible that the satellite beam serving the terminal device located on the ground will change frequently. The changed satellite beam can be referred to as a target satellite beam.

[0240] In the above process, each terminal device needs to determine the target satellite beam corresponding to the terminal device through an independent signaling transmission process. For example, when beam switching occurs, the satellite network device corresponding to the source satellite beam can independently initiate a switching process (such as cell switching) for all terminal devices in the connected state within the beam coverage, so as to switch the terminal device from the source satellite beam to the target satellite beam after determining the target satellite beam. For example, for the terminal device in the idle state, after the beam in which the terminal device camps is switched, the terminal device needs to perform cell and satellite search (such as cell reselection) again, so as to determine and access the target satellite beam (such as camping on the target satellite beam).

[0241] However, each terminal device needs to determine the target satellite beam corresponding to each terminal device through an independent signaling transmission process, which will cause a sharp increase in signaling overhead, and further increase the power consumption of the terminal device.

[0242] To solve the above problems, the present application provides a communication method and related devices, which will be described in detail below in conjunction with the accompanying drawings.

[0243] Please refer to FIG. 5, which is an implementation schematic diagram of the communication method provided by the present application, and the method includes the following steps.

[0244] It should be understood that in the following, the first communication device is taken as an example of the execution subject of the interaction schematic, but the present application does not limit the execution subject of the interaction schematic. For example, any one of the first communication device to the fourth communication device can be a communication device, or part of the components (such as a chip, a baseband chip, a modem chip, a SoC chip containing a modem core, a SIP chip, a communication module, a chip system, a processor, a logic module or software, etc.) in the communication device.

[0245] As an example, the first communication device in the following can be a first terminal device, or the first communication device can be part of the components in the first terminal device.

[0246] As an example, the second communication device in the following can be a first network element or a source network device (which can be a source satellite network device, and hereinafter the source network device is described as a source satellite network device), or the first communication device can be part of the components in the first network element or the source satellite network device.

[0247] As an example, the third communication device in the following can be a target network device or a target satellite network device (hereinafter described as a target satellite network device), or the first communication device can be part of the components in the target satellite network device.

[0248] As an example, the communication device corresponding to the fourth communication device in the following can be a core network device, or the first communication device can be part of the components in the core network device.

[0249] Optionally, in the following scheme, the access network device (such as the source satellite network device, the target satellite network device, etc.) can be an ORAN network element.

[0250] S501. The second communication device sends first information, and the first communication device receives the first information, the first information being used to indicate information of N satellite beams; in each time period of K time periods, a signal coverage area of at least one satellite beam of the N satellite beams comprises a first geographic area. Wherein, the K time periods are continuous time periods with the same length, K and N are positive integers; when receiving the first information, a terminal device located in the first geographic area comprises a first terminal device.

[0251] S502. The first communication device determines a target satellite beam for communicating with the first terminal device based on the information of the N satellite beams. Wherein, the target satellite beam is contained in the N satellite beams.

[0252] It should be understood that the scheme provided by the present application can be applied to a beam-based communication scenario, and beams are taken as satellite beams in this paper for example. Alternatively, the satellite beams can be replaced by other terms, such as beams, cells, satellite cells, communication beams, satellite communication beams, NTN beams, NTN communication beams,

[0253] It should be understood that the signal coverage area of the satellite beam can be understood as a geographic area where the signal of the satellite beam is reachable / servable / available for communication. For example, the signal coverage area of the satellite beam can comprise one or more geographic areas, and a terminal device located in the one or more geographic areas can communicate through the satellite beam.

[0254] Alternatively, the signal coverage area can be replaced by other terms, such as a servable area, a service area, a signal available area, a signal reachable area, a communication area, or a communicable area, etc.

[0255] It should be understood that the K time periods are continuous time periods with the same length, which can be understood as the K time periods being connected at both ends and each time period having the same length; or, the terminal time of the k(th) (k takes a value from 1 to K-1) time period of the K time periods is the starting time of the k+1(th) time period of the K time periods, and the starting time of the k(th) time period is the terminal time of the k-1(th) time period of the K time periods; or, the last time unit of the k(th) (k takes a value from 1 to K-1) time period of the K time periods is adjacent to the starting time unit of the k+1(th) time period of the K time periods, wherein the time unit can be a symbol, a time slot, a subframe, a frame, a millisecond, a microsecond, a minute, a second, or a minute, etc.

[0256] In a possible implementation, the first information received by the first communication apparatus in step S501 can indicate information of the N satellite beams, wherein the information of any satellite beam comprises at least one of the following: information of a satellite corresponding to the satellite beam, communication frequency information of the satellite beam, cell information corresponding to the satellite beam, geographical area information covered by the satellite beam, or service time information of the satellite beam.

[0257] For example, the information of the satellite corresponding to the satellite beam can indicate the satellite corresponding to the satellite beam, for example, the information of the satellite corresponding to the satellite beam can comprise one or more of the following: an identifier of the satellite, a number of the satellite, ephemeris of the satellite, coordinates of the satellite, and a time at which the coordinates are located, or other information.

[0258] For another example, the communication frequency information of the satellite beam can indicate the communication frequency corresponding to the satellite beam, for example, the communication frequency information of the satellite beam can comprise a start frequency point and / or a stop frequency point of the communication frequency, or the communication frequency information of the satellite beam can comprise an index corresponding to the communication frequency.

[0259] For another example, the cell information corresponding to the satellite beam can indicate the cell corresponding to the satellite beam, for example, the cell information corresponding to the satellite beam can comprise one or more of the following: a cell identifier (cell ID) of the cell, a physical cell identifier (PCI), or other information.

[0260] For another example, the geographical area information covered by the satellite beam can be understood as geographical area information of a signal coverage range of the satellite beam. For example, the geographical area information covered by the satellite beam can indicate one or more geographical areas contained in the signal coverage range of the satellite beam, or the geographical area information covered by the satellite beam can also be identifier information of a ground fixed cell / area.

[0261] For another example, the service time information of the satellite beam can indicate one or more of the following: start time information (for example, a start time or a start time unit), a duration, and termination time information (for example, a termination time or a termination time unit) of service provided by the satellite beam. For example, the service time of the satellite beam refers to a time at which the satellite beam serves a geographical area covered by the satellite beam and included in the information of the satellite beam.

[0262] Optionally, the first information received by the first communication apparatus in step S501 can be carried in a multicast message or a broadcast message, so that one or more terminal devices can obtain the first information through the multicast message or the broadcast message, and transmission overhead of the information of the satellite beam can be reduced.

[0263] Optionally, the N satellite beams correspond to one or more satellite network devices, and information of the N satellite beams is determined based on one or more of ephemeris information of the one or more satellite network devices, topology information of a constellation to which the one or more satellite network devices correspond, and configuration information of the constellation. For example, the second communication device can determine the information of the N satellite beams based on the ephemeris information of the one or more satellite network devices and / or the topology information of the constellation to which the one or more satellite network devices correspond. The topology information of the constellation indicates deployment of satellites in the constellation, and based on the topology information of the satellites, the position and the movement speed of each satellite in the constellation at any time can be determined. For example, the topology information of the constellation can include ephemeris information of each satellite in the constellation. In addition, the configuration information of the constellation can include one or more of a frequency used by a satellite beam of a satellite in the constellation, a staring time period information (i.e., a length of time for serving a geographical area) and a staring time of the satellite beam, and a physical cell identity corresponding to the satellite beam.

[0264] It should be noted that the frequency used by a satellite beam can be related to a geographical area served by the satellite beam, for example, different frequencies are used when a same satellite beam of a same satellite serves different geographical areas. The frequency used by a satellite beam can also be irrelevant to the geographical area served by the satellite beam, i.e., the same frequency is used by the satellite beam when serving any geographical area. The staring time period and the staring time of a satellite beam can be configured to be the same for the entire constellation, i.e., the staring time period and the staring time of any satellite beam of any satellite in the entire constellation are the same. For example, all satellite beams start to stare at a ground area at time t1, and change the ground area they stare at with a period T. The staring time period and the staring time of a satellite beam can also be configured per satellite, i.e., the staring time period and the staring time of satellite beams of different satellites can be different.

[0265] As an example, the second communication device can be a first network element or a part of the first network element, i.e., the information of the N satellite beams can be determined by the first network element. The first network element can be a topology server or a topology service in a non-terrestrial network, or the first network element can be a topology server or a topology service in a satellite network, or the first network element can be a hardware and / or software module integrated in a network device, which can be an access network device or a core network device. In the above step S501, the second communication device can send the first information to a network device (e.g., a source satellite network device), or the second communication device can send the first information to a first terminal device corresponding to the first communication device (or one or more terminal devices located in a first geographic area), or the second communication device can send the first information to a first terminal device corresponding to the first communication device (or one or more terminal devices located in a first geographic area) through a network device (e.g., a source satellite network device).

[0266] As another example, the second communication device can be a source network device (e.g., a source satellite network device) or a part of the source network device, i.e., the information of the N satellite beams can be determined by the source network device. The source network device can be an NTN network device, which can be referred to as a source satellite network device, and hereinafter the source network device is taken as an example of the source satellite network device. In the above scheme, the second communication device can send the first information to a first terminal device corresponding to the first communication device (e.g., one or more terminal devices located in a first geographic area). Optionally, the second communication device can locally determine the first information in a manner of obtaining the first information. For example, the second communication device can determine the information of the N satellite beams based on one or more of ephemeris information of the one or more satellite network devices, topology information of a constellation corresponding to the one or more satellite network devices, and configuration information of the constellation. Alternatively, the second communication device can obtain the first information in a manner of receiving the first information. For example, the first information can come from a first network element.

[0267] Based on the scheme shown in FIG. 5, the first information received by the first communication apparatus in step S501 is used to indicate the information of the N satellite beams, and thereafter, in step S502, the first communication apparatus can determine the target satellite beam for communicating with the first terminal device based on the information of the N satellite beams. Wherein, in each time period of the K time periods, the signal coverage area of at least one satellite beam of the N satellite beams includes the first geographic region, and when the first communication apparatus receives the first information, the terminal devices located in the first geographic region include the first terminal device. In other words, any terminal device located in the first geographic region can determine the target satellite beam based on the information of the N satellite beams indicated by the first information. In this way, at any time period of the K time periods, when the beams of the satellite move, one or more terminal devices located in the same geographic region can determine the target satellite beam based on the first information, which can reduce the latency of the terminal devices blindly searching for the satellite and the satellite beam, thereby reducing the service latency, improving the service experience, reducing the power consumption of the terminal devices, and improving the communication efficiency.

[0268] In the above scheme, one or more terminal devices located in the same geographic region can reuse the same information (i.e., the information of the N satellite beams indicated by the first information) to determine the target satellite beam, which can greatly reduce the signaling overhead, thereby improving the communication efficiency.

[0269] In a possible implementation of the method shown in FIG. 5, in each time period of the K time periods, the signal coverage area of at least one satellite beam of the N satellite beams includes the second geographic region, and the first geographic region is adjacent to the second geographic region. Accordingly, when the first terminal device moves from the first geographic region to the second geographic region, the first terminal device can determine the target satellite beam according to the information of the satellite beam whose coverage area includes the second geographic region in any time period of the K time periods. In this way, when the first terminal device moves from the first geographic region to the second geographic region, the first terminal device can still determine the target satellite beam by using the first information, thereby maintaining the continuity of the communication. Compared with the terminal device blindly searching for the satellite and the satellite beam without the first information in any time period of the K time periods, the latency of the satellite and cell search can be greatly reduced, thereby reducing the service latency, improving the service experience, reducing the power consumption of the terminal devices, and improving the communication efficiency.

[0270] It should be noted that the first geographic region and the second geographic region can have a partially overlapping region, or can have no overlapping region, which is not limited herein.

[0271] In a possible implementation of the method shown in FIG. 5, in step S502, the process in which the first communication device determines the target satellite beam for communication with the first terminal device based on the information of the N satellite beams can include: the first communication device determines M satellite beams from the N satellite beams based on the information of the N satellite beams, the M satellite beams being used to determine the target satellite beam; wherein the signal coverage area of any one of the M satellite beams contains the geographic area where the first terminal device is currently located, the geographic area where the first terminal device is currently located being contained in the first geographic area or the second geographic area, and M is less than or equal to N.

[0272] Specifically, the first communication device can determine M satellite beams from the N satellite beams, that is, the M satellite beams can be candidate satellite beams. Moreover, the signal coverage area of any one of the M satellite beams contains the geographic area where the first terminal device is currently located, so that the first communication device can select / determine the target satellite beam from the candidate satellite beams serving the geographic area where the first terminal device is currently located, which can realize fast determination of the target satellite beam and also avoid the situation that a certain satellite beam whose signal coverage area does not contain the geographic area where the first terminal device is currently located is determined as the target satellite beam, resulting in communication failure.

[0273] Optionally, in the case that the first terminal device moves or remains stationary in the first geographic area, the geographic area where the first terminal device is currently located is contained in the first geographic area.

[0274] Optionally, in the case that the first terminal device moves from the first geographic area to the second geographic area, the geographic area where the first terminal device is currently located is contained in the second geographic area.

[0275] As an example, in the N satellite beams, the time length for which the M satellite beams serve the geographic area where the first terminal device is currently located is greater than or equal to the time length for which the other N-M satellite beams serve the geographic area where the first terminal device is currently located. In other words, in the N satellite beams, the M satellite beams as candidate beams serve the geographic area where the first terminal device is currently located for a longer time length. In this way, the first communication device can select the M satellite beams with a longer service time length as candidate beams, and can select the satellite beam with a longer service time length as the target communication beam as much as possible, which can reduce the frequency of re-determining the target satellite beam (for example, beam switching / beam reselection), and further reduce the communication overhead.

[0276] It should be understood that the time length for which a satellite beam serves a certain geographical area can be understood as a service time length for which the satellite beam serves the geographical area, a remaining service time length, a serviceable time length, a remaining serviceable time length, an available time length, a remaining available time length, a communication time length, a remaining communication time length, a communicable time length, or a remaining communicable time length, etc.

[0277] In the above process, after the first communication device determines the M candidate satellite beams from the N satellite beams, the first communication device can further receive at least one signal from part or all of the M satellite beams, and perform a measurement based on the at least one signal to obtain a measurement result for determining the target satellite beam. In this way, the first communication device can determine / select a satellite beam with better signal quality from the M candidate satellite beams as the target satellite beam, so as to improve the communication quality of subsequent communication of the first communication device based on the target satellite beam.

[0278] Optionally, the measurement result can be used to characterize the signal quality, for example, the measurement result can include one or more of a reference signal receiving power (RSRP), a reference signal receiving quality (RSRQ), a signal and interference plus noise ratio (SINR), or other parameters.

[0279] In the method shown in FIG. 5, after the first communication device determines the target satellite beam in step S502, the first communication device can perform various communication processes based on the target satellite beam, which will be described below in combination with some implementation examples.

[0280] Example A: the first communication device camps on a target satellite cell (or a target satellite network device) corresponding to the target satellite beam.

[0281] In example A, the first communication device can receive a first signal of the target satellite beam for synchronization, so that the first terminal device can camp on the target satellite cell (or the target satellite network device) corresponding to the target satellite beam based on the target satellite beam to obtain synchronization (e.g., downlink synchronization). Optionally, in the case that the first terminal device is in a radio resource control idle state (RRC_IDLE) or a radio resource control inactive state (RRC_INACTIVE), the first terminal device camps on the target satellite cell (or the target satellite network device) corresponding to the target satellite beam. For example, the camping of the terminal device on the target satellite cell means that the terminal device maintains downlink synchronization with the target satellite cell and can receive broadcast messages and paging messages from the target satellite cell, etc.

[0282] In example B, the first communication device performs a random access channel (RACH) procedure through the target beam to switch to a target satellite cell (or a target satellite network device) corresponding to the target satellite beam.

[0283] As an example, as shown in FIG. 6, compared with the method shown in FIG. 5, in example B, the first communication device can switch to a target satellite cell (or a target satellite network device) corresponding to the target satellite beam through the RACH procedure of step F. In FIG. 6, the network device corresponding to the third communication device is taken as an example of the target satellite network device corresponding to the target satellite cell corresponding to the target satellite beam.

[0284] In example B, the first communication device can perform the RACH procedure through the target beam, so that the first terminal device can switch from the source network device to the target satellite network device corresponding to the target satellite beam. Optionally, when the first terminal device is in a radio resource control connected state (RRC_CONNECTED), the first terminal device can also camp on the target satellite cell (or the target satellite network device) corresponding to the target satellite beam, that is, without initiating the RACH procedure.

[0285] Optionally, in example B, the first communication device performing the RACH procedure through the target beam includes that the first communication device sends a RACH request message through the target beam.

[0286] Optionally, when the first terminal device receives the first information in step S501, the first terminal device can be in RRC_IDLE or RRC_INACTIVE, and the first terminal device can camp on the source cell. Correspondingly, the first communication device can perform the process of example A described above. Alternatively, when the first terminal device receives the first information in step S501, the first terminal device can be in RRC_CONNECTED, and the first terminal device can establish a radio resource control (RRC) connection with the source cell. Correspondingly, the first communication device can perform the process of example B described above. The source cell can be an NTN cell, that is, the network device corresponding to the source cell can be an NTN network device or a source satellite network device.

[0287] In a possible implementation manner of example B, the receiving moment or the sending moment of the first information in step S501 is within a first time period (the first time period can be any one of K time periods). In addition, in step F, the first communication device performing the RACH procedure through the target beam includes any one of the following:

[0288] The first communication device performs the RACH procedure through the target beam at a starting time (or starting moment) of a next time period of the first time period; or

[0289] The first communication device performs the RACH procedure through the target beam at a starting time (or starting moment) of a next time period of the first time period after a first time length, a quantity of time units included in the first time length being determined based on a random number, and the quantity of time units included in the first time length being less than or equal to a threshold value.

[0290] Specifically, the first communication device can perform the RACH procedure based on any of the above to improve the flexibility of the implementation of the scheme. Moreover, in the case where the first communication device performs the RACH procedure based on the first time length, since the quantity of time units included in the first time length is determined based on a random number, one or more terminal devices located in the same geographical area (for example, the first geographical area) can perform the RACH procedure based on the random number within a specified time length, which can not only enable the one or more terminal devices to complete access within the specified time length, but also avoid or reduce the occurrence of conflicts caused by different terminal devices performing the RACH procedure at the same time, so as to improve the communication efficiency.

[0291] Correspondingly, the first information can include the threshold value, that is, the first communication device obtains the threshold value from the second communication device through a broadcast or groupcast message, or the threshold value can also be pre-configured in the first communication device, or the threshold value can also be predefined through a standard / protocol.

[0292] In another possible implementation of example B, as shown in FIG. 6, the method shown in FIG. 5 further includes:

[0293] Step A. The second communication device sends second information, and correspondingly, the first communication device receives the second information. The second information is used to indicate switching the source satellite beam to which the first terminal device is connected. Moreover, in step F, the first communication device performs the RACH procedure through the target beam includes any of the following:

[0294] The first communication device performs the RACH procedure through the target beam immediately after receiving the second information in step A; or

[0295] The first communication device performs the RACH procedure through the target beam after delaying for a second time length after receiving the second information in step A, a quantity of time units included in the second time length being determined based on a random number, and the quantity of time units included in the second time length being less than or equal to a threshold value. Correspondingly, the second information can include the threshold value, or the threshold value can be pre-configured in the first communication device, or the threshold value can also be predefined through a standard / protocol.

[0296] Specifically, the first communication device can perform the RACH procedure based on any of the above to improve flexibility of the implementation of the scheme. Also, in a case where the first communication device performs the RACH procedure based on the second time duration, since the number of time units contained in the second time duration is determined based on the random number, one or more terminal devices located in the same geographical area (e.g., the first geographical area) can perform the RACH procedure based on the random number within the specified time duration, which can not only enable the one or more terminal devices to complete access within the specified time duration, but also avoid or reduce the occurrence of a situation where different terminal devices perform the RACH procedure at the same time, thereby improving communication efficiency.

[0297] Optionally, the second information can be sent in a broadcast or groupcast manner, and correspondingly, the second information is used to indicate switching of a source satellite beam to which one or more terminal devices (including the first terminal device) located in the same geographical area (e.g., the first geographical area) are connected. In this way, the second information can implement batch switching indication of the one or more terminal devices in the same geographical area, thereby reducing overhead.

[0298] In a possible implementation, the first communication device can also obtain the switching indication based on other manners. For example, the first information received by the first communication device in step S501 is also used to indicate switching of the source satellite beam to which the first terminal device is connected. In other words, in addition to the information used to indicate the N satellite beams, the first information can also be used to indicate switching of the source satellite beam to which the first terminal device is connected, which can multiplex the first information to indicate more information, thereby reducing overhead.

[0299] Optionally, the first information is also used to indicate switching of a source satellite beam to which one or more terminal devices (including the first terminal device) located in the same geographical area (e.g., the first geographical area) are connected. In this way, the first information can implement batch switching indication of the one or more terminal devices in the same geographical area, thereby reducing overhead.

[0300] In a possible implementation, taking the second communication device as an example, the source satellite beam of the first terminal device corresponds to a satellite network device. As shown in FIG. 6, the method shown in FIG. 5 further includes:

[0301] Step B. The first communication device sends third information, and the second communication device receives the third information accordingly. The third information is used to request switching the first terminal device from the source satellite beam to the target satellite beam. Specifically, when the first communication device moves from the first geographic area to the second geographic area, the first communication device can also send third information used to request switching the first terminal device from the source satellite beam to the target satellite beam, so that the receiver of the third information can initiate the execution of the switching process of the first terminal device based on the request, to realize the switching of the satellite cell or satellite network device connected by the first terminal device.

[0302] Optionally, the third information includes the identifier of the target satellite beam and / or the identifier of the target satellite cell, so that the receiver of the third information switches the first terminal device to the target satellite cell or target satellite network device corresponding to the target satellite beam based on the identifier.

[0303] In a possible implementation, the second communication device starts to cache the data packets of one or more terminal devices located in the first geographic area after the second communication device sends the first information in step S501 or after the second communication device sends the second information in step A or at the start time of the next time period of the first time period (as in the previous example A). In other words, after the second communication device sends the first information or the second information or at the start time of the next time period of the first time period, the second communication device can determine that one or more terminal devices located in the first geographic area will possibly be switched, and therefore, the second communication device can start to cache the data packets of one or more terminal devices located in the first geographic area, so that the target satellite network device after switching can obtain the data packets cached by the second communication device, to prevent or reduce the occurrence of packet loss during the cross-satellite beam switching of the terminal, and to improve the service continuity.

[0304] Optionally, after the second communication device sends the first information or the second information or at the start time of the next time period of the first time period, the second communication device can cache the data packets of one or more terminal devices located in the first geographic area in multiple ways.

[0305] For example, after the second communication device sends the first information or the second information or at the start time of the next time period of the first time period, the second communication device immediately starts to cache the data packets of one or more terminal devices located in the first geographic area.

[0306] In a possible implementation, the method further includes: determining, by the second communication device, P candidate satellite beams from the N satellite beams, P being less than or equal to N (optionally, P being greater than or equal to M); and sending, by the second communication device, fourth information to one or more satellite network devices corresponding to the P satellite beams, the fourth information including context information of one or more terminal devices located in the first geographic region. In other words, the second communication device can determine the one or more satellite network devices corresponding to the P candidate satellite beams as candidate satellite network devices, and the second communication device can send the fourth information to the candidate satellite network devices, so that after one or more terminal devices located in the first geographic region perform handover through a target satellite beam from the P satellite beams, the target satellite network device after handover can obtain the context information of the terminal devices, thereby improving service continuity.

[0307] Optionally, the context information of the one or more terminal devices included in the fourth information includes second tunnel information allocated by the source satellite network device, the second tunnel information being used to determine a radio bearer and / or a session of the one or more terminal devices corresponding to the received downlink data packet, the radio bearer and / or the session being used to transmit the downlink data packet of the one or more terminal devices. Specifically, the fourth information sent by the second communication device can include the second tunnel information allocated by the source satellite network device, so that the receiver of the fourth information can determine the radio bearer and / or the session based on the second tunnel information, and transmit the data packet of the terminal device based on the determined radio bearer or session, thereby improving service continuity.

[0308] For example, the second communication device can determine P satellite beams from the N satellite beams, that is, the P satellite beams can be candidate satellite beams. In addition, the signal coverage area of any satellite beam from the P satellite beams includes the geographic region where the first terminal device is currently located, which can avoid sending the context of the first terminal device and the forwarding data of the first terminal device to a satellite network device corresponding to a satellite beam whose signal coverage area does not include the geographic region where the first terminal device is currently located, thereby reducing signaling overhead.

[0309] It should be noted that the second communication device can send the fourth information to the one or more satellite network devices corresponding to the P satellite beams in various ways, which will be described below in combination with some possible implementations. In the following examples, one of the one or more satellite network devices corresponding to the P satellite beams is taken as a third communication device.

[0310] In a first mode, the fourth information is sent to the one or more satellite network devices corresponding to the P satellite beams via an interface between the source satellite network device corresponding to the source satellite beam and the one or more satellite network devices corresponding to the P satellite beams.

[0311] For example, as shown in FIG. 6, the foregoing method further includes:

[0312] Step C. The second communication device sends the fourth information, and correspondingly, the third communication device receives the fourth information. The implementation of the fourth information can refer to the foregoing description.

[0313] In a second mode, the fourth information is sent to the one or more satellite network devices corresponding to the P satellite beams via the core network device.

[0314] For example, as shown in FIG. 6, the foregoing method further includes:

[0315] Step D. The second communication device sends a first message to a fourth communication device (the fourth communication device corresponds to the core network device), and correspondingly, the fourth communication device receives the first message. The first message includes the fourth information, and the implementation of the fourth information can refer to the foregoing description.

[0316] Step E. The fourth communication device sends the fourth information, and correspondingly, the third communication device receives the fourth information.

[0317] When the P satellite beams correspond to multiple satellite network devices, the second communication device sends the fourth information to the multiple satellite network devices via the first mode and / or the second mode, that is, for different satellite network devices, the second communication device can select different modes to send the fourth information.

[0318] In a possible implementation, the method further includes: the second communication device receives first tunnel information, the first tunnel information being used to receive data packets of one or more terminal devices located in the first geographic area and forwarded by the source satellite network device corresponding to the source satellite beam; and the second communication device forwards the data packets of the one or more terminal devices located in the first geographic area based on the first tunnel information, and / or sends the data packets cached for the one or more terminal devices via the first tunnel information. Specifically, the second communication device can also receive the first tunnel information and send data packets associated with the one or more terminal devices located in the first geographic area based on the first tunnel information, so that the receiver of the associated data packets can subsequently transmit the associated data packets after the terminal device is switched to improve service continuity.

[0319] It should be noted that the first tunnel information received by the second communication device can come from the third communication device, wherein the first tunnel information can be sent by the third communication device to the second communication device through an interface between the third communication device and the second communication device. The second communication device can be a source satellite network device corresponding to a source satellite beam, and the third communication device can be a target satellite network device corresponding to a target satellite beam.

[0320] Optionally, the first tunnel information received by the second communication device can come from the fifth communication device, and at this time, the first tunnel information can be sent by the fourth communication device to the second communication device. The second communication device can be a source satellite network device corresponding to a source satellite beam, and the fifth communication device is responsible for forwarding data between the second communication device and the third communication device. The first tunnel information can be obtained by the fourth communication device from the fifth communication device, or determined by the fourth communication device. In this scenario, the second communication device buffers the data packets of the one or more terminal devices, or forwards the received data packets of the one or more terminal devices to the second communication device through the fifth communication device.

[0321] When the first tunnel information received by the second communication device comes from the fifth communication device, in a possible implementation, the foregoing method further includes: the third communication device sends fifth information to the fourth communication device, the fifth information indicating tunnel information of a target satellite network device corresponding to a target satellite beam, and the tunnel information of the target satellite network device being used for the target satellite network device to receive the forwarding data of the one or more terminal devices. Specifically, the third communication device can send fifth information indicating the tunnel information of the target satellite network device corresponding to the target satellite beam to the fourth communication device, so that the fourth communication device can instruct the fifth communication device to send the forwarding data of the one or more terminal devices received by the second communication device through the first tunnel to the third communication device based on the tunnel information of the target satellite network device, so that after the one or more terminal devices switch to the third communication device, the third communication device can transmit the received forwarding data, thereby improving service continuity.

[0322] Optionally, the process of establishing a tunnel between the target satellite network device corresponding to the target satellite beam and the source satellite network device based on the tunnel information of the target satellite network device by the fourth communication device includes: the fourth communication device obtains tunnel information of the fifth communication device, and the tunnel information of the first network element is used to receive the forwarding data of the one or more terminal devices from the source satellite network device; and the fourth communication device sends indication information to the fifth communication device, and the indication information is used to instruct the fifth communication device to send the forwarding data of the one or more terminal devices received by the source satellite network device through the first tunnel to the target satellite network device through the tunnel of the target satellite network device.

[0323] In a possible implementation, after the third communication device obtains the fourth information through step C of method one or step E of method two, the third communication device can also cache the received data packets of one or more terminal devices located in the first geographic area and forwarded by the source satellite network device, so that the third communication device can transmit the cached data packets after the one or more terminal devices switch to the target satellite beam, thereby improving service continuity.

[0324] It should be noted that after the third communication device caches the received data packets of one or more terminal devices located in the first geographic area and forwarded by the source satellite network device, the third communication device can process the cached data packets in various ways, which will be described below in conjunction with some examples.

[0325] Example one, the cached data packets include data packets of the first terminal device, and the foregoing method further includes: after determining that the first terminal device successfully performs the RACH procedure, the third communication device sends the cached data packets to the first terminal device.

[0326] Example two, the data packets of one or more terminal devices located in the first geographic area and forwarded by the source satellite network device include data packets of the first terminal device, and the foregoing method further includes: after determining that the first terminal device successfully performs the RACH procedure, the third communication device sends the data packets of the first terminal device to the first terminal device.

[0327] Example three, the context information of the one or more terminal devices includes context information of a second terminal device, and the foregoing method further includes: the third communication device starts a timer after receiving the context information of the second terminal device, and releases the context information of the second terminal device if the timer expires and the second terminal device does not access. Specifically, in the case where the timer expires and the second terminal device does not access, the third communication device can determine that the second terminal device will not likely switch to the third communication device, and therefore, the third communication device can release the context information of the second terminal device to save storage overhead.

[0328] Optionally, in Example Three, in the case that the timer expires and the second terminal device does not access, the foregoing method further comprises: if the second terminal device has buffered the data packet forwarded from the source satellite network device, the third communication device releases the data packet buffered for the second terminal device. In the case that the timer expires and the second terminal device does not access, the third communication device can determine that the second terminal device will likely not switch to the third communication device, and therefore, the third communication device can release the data packet buffered for the second terminal device from the source satellite network device, so as to save storage overhead.

[0329] In order to facilitate the understanding of the foregoing schemes shown in FIG. 5 and FIG. 6, more examples will be described below.

[0330] Referring to FIG. 7a, another schematic diagram of the communication method provided by the present application is shown. For the convenience of subsequent reference, the method shown in FIG. 7a is referred to as Example One. In the example shown in FIG. 7a, the first communication device is a UE, the second communication device is a source satellite network device (i.e., a network device corresponding to a beam 1), one or more candidate satellite beams correspond to a network device (in the figure, two candidate satellite beams correspond to network devices, which are a network device corresponding to a candidate satellite beam 1 (i.e., a network device corresponding to a beam 2) and a network device corresponding to a candidate satellite beam 2 (i.e., a network device corresponding to a beam 3)), one of the network devices is the third communication device, and the first network element and the source satellite network device are different devices.

[0331] Step 1. The first network element sends first information to the source satellite network device. The first information is described with reference to FIG. S501.

[0332] The first information can also indicate a beam corresponding to the first information. The present embodiment takes the beam 1 corresponding to the first information as an example for description. The beam 1 corresponding to the first information means that the first geographical area corresponding to the first information overlaps with the coverage area of the beam 1 of the source satellite network device.

[0333] For example, the first network element can calculate the ground coverage area of each satellite beam in each time period according to the topology of the satellite constellation and / or each satellite ephemeris. In addition, the first network element determines the first information according to the ground coverage information of each satellite beam in each time period of the K time periods, and the first information indicates information (or auxiliary information) of N satellite beams, wherein the N satellite beams include at least one of the following:

[0334] In the current time period, the information of a satellite beam covering a second geographical area, the second geographical area being a geographical area adjacent to the first geographical area;

[0335] the satellite beams covering the first geographic region in K-1 time periods after the current time period; or

[0336] the satellite beams covering the second geographic region in K-1 time periods after the current time period.

[0337] The information of any one of the N satellite beams includes at least one of the following:

[0338] information of a satellite corresponding to the satellite beam, a frequency of the satellite beam, an identifier of a satellite cell to which the satellite beam belongs (a satellite cell can include only one satellite beam or multiple satellite beams), area information covered by the satellite beam (such as a center position and a radius of a ground beam, or an identifier of a ground cell (for a ground fixed cell scenario)), or time period information in which the satellite beam serves the geographic region (such as a start serving time, or a start serving time + an end time, or a start serving time + a serving market, or an end serving time). The information of the satellite corresponding to the satellite beam includes a satellite identifier and a satellite ephemeris, and the satellite ephemeris can include time, a position coordinate of the satellite, and a moving speed of the satellite.

[0339] Step 2. The source satellite network device (i.e., a network device corresponding to beam 1) sends the first information to the UE in its coverage range. After receiving the first information in step 1, the source satellite network device sends the first information to the UE through beam 1 corresponding to the first information.

[0340] It should be noted that step 2 is an example of implementation of the foregoing step S501, and the implementation processes of the two steps can be mutually referred.

[0341] Optionally, the source satellite network device (i.e., a network device corresponding to beam 1) can send the first information to the UE in a broadcast manner, or in a groupcast manner. For example, when the area served by the satellite beam is a ground fixed area (such as the scenario shown in FIG. 3b), the satellite beam can send the first information to the UE in a broadcast manner; when the geographic area served by the satellite beam is not fixed (such as the scenario shown in FIG. 3c), the satellite beam can send the first information to the UE in a groupcast manner.

[0342] For example, as shown in FIG. 3c, in the next time period, the satellite beams covering the area of beam 1 (beam 1 in the figure) include beam 2, beam 3 and beam 4. Accordingly, beam 1 can divide the UEs in the area covered by beam 2, beam 3 and beam 4 in the next time period into three multicast groups, and send the first information to the UEs in the form of multicast. The first information received by the UE group in the area covered by beam 2 in the next time period includes the information of beam 2, the first information received by the UE group in the area covered by beam 3 in the next time period includes the information of beam 3, and the first information received by the UE in the area covered by beam 4 in the next time period includes the information of beam 4. In this scenario, the satellite network device can determine different first information for different areas covered by beam 1 according to the first information to send to different UE groups. In order to reduce complexity, the first information can also be sent to all UEs in the coverage of beam 1 in the form of broadcast in this scenario, and the target satellite beam is determined by the UE according to the beam coverage information in the first information.

[0343] It should be noted that even for the scenario of satellite covering a fixed ground (as shown in FIG. 3b), in the next time period, the satellite covering the geographic area can also include one or more, i.e. there can be multiple satellites that can cover the same geographic area. At this time, the first information can include the information of multiple satellite beams.

[0344] In some embodiments, the first network element can directly send the first information to the UE, in which case the satellite base station can not be aware of the first information (or pass through the first information). For example, the UE can establish a data channel with the first network element, such as establishing a non-access stratum (NAS) connection or establishing an internet protocol (IP) connection, so that the first network element sends the first information to the UE. This scenario is not presented in FIG. 7a. In this case, the first information sent by the first network element to the UE can include the information of the satellite beams covering the location of the UEs in more time periods than the current time period and the next time period, which can reduce the frequency of sending the first information by the first network element to the terminal and reduce the air interface overhead.

[0345] Step 3. The UE determines that beam 1 ends service and beam 2 starts service. For example, the UE determines the time when beam 1 ends service and the candidate satellite beam serving the location of the UE in the next time period according to the first information.

[0346] For example, the candidate satellite beam can be M satellite beams out of N satellite beams. Taking M=2 as an example, the M satellite beams can include beam 2 and beam 3 in FIG. 7a, beam 2 corresponds to the network device_1 corresponding to the candidate satellite beam, and beam 3 corresponds to the network device_2 corresponding to the candidate satellite beam.

[0347] Optionally, according to the description of step 2, the area served by beam 1 in time period 1 can be covered by multiple satellite beams in the next time period, and the coverage areas of these satellite beams can overlap (as shown in the scenario of FIG. 3b) or can not overlap (as shown in the scenario of FIG. 3c). It is assumed here that the location of the UE is covered by two satellite beams, beam 2 and beam 3, in the next time period.

[0348] Step 4a. The UE synchronizes with beam 2 and performs signal quality measurement to obtain a measurement result.

[0349] Step 4b. The UE synchronizes with beam 3 and performs signal quality measurement to obtain a measurement result.

[0350] Specifically, at the beginning of the next time period, the UE can perform downlink synchronization with beam 2 and beam 3, respectively. For example, the UE terminal can perform downlink synchronization according to the information of beam 2 and beam 3 included in the first information.

[0351] As an example, the information of the satellite beam indicated by the first information includes the identity and ephemeris information of the satellite corresponding to the satellite beam; accordingly, the UE can calculate the coordinates of the satellite in space at present according to the ephemeris information, so as to determine the direction and elevation angle of receiving beam 2 and beam 3, so that the UE can align the satellite to obtain a stronger downlink signal.

[0352] As an example, the information of the satellite beam indicated by the first information includes the identity of the satellite cell and the spectrum information of the satellite beam, and the UE can perform downlink synchronization based on the information to reduce the time of cell search. In addition, the UE can read the broadcast information of the satellite cell after downlink synchronization, and can perform measurement on beam 2 and beam 3 to determine which satellite beam has better signal quality.

[0353] Step 5. The UE selects a target satellite beam and camps on the target satellite beam.

[0354] It should be noted that step 5 is an example of the implementation of the foregoing step S502, and the implementation processes of the two steps can be mutually referred.

[0355] Specifically, the UE can select a target satellite beam based on the measurement results of step 4a and step 4b. For example, the UE selects a satellite beam with better signal quality as the target satellite beam, and it is assumed that the signal quality of beam 2 is better than that of beam 3, and the UE selects beam 2 as the target satellite beam in this embodiment.

[0356] Optionally, the UE can also consider the time when the target satellite beam serves when selecting the target satellite beam. For example, the UE can determine which satellite beam serves the area for a longer time period according to the time when the target satellite beam serves the area. The UE can select the satellite beam that serves for a longer time as the target satellite beam. Of course, the UE can consider the above conditions comprehensively to select the target satellite beam. For example, the UE can give priority to the signal quality and consider the serving time when the signal quality of two is the same. Alternatively, the UE can also use other algorithms. For example, the UE can use a weighted average to calculate a priority coefficient according to the signal quality and the serving time, and then select the target satellite beam according to the priority coefficient.

[0357] Step 6. The terminal camps on the target satellite beam (for example, beam 2).

[0358] Wherein, the terminal and the target satellite beam keep downlink synchronization, including one or more of reading broadcast information, reading a paging channel or other processes.

[0359] Please refer to FIG. 7b, another schematic diagram of the communication method provided by the present application. For the convenience of the following reference, the method shown in FIG. 7b is referred to as embodiment two. In the example shown in FIG. 7b, the first communication device is the UE, the second communication device and the third communication device are located in the same network device (i.e., the source network device corresponding to the source beam and the target network device corresponding to the target beam are the same satellite network device), and the first network element and the source satellite network device are different devices.

[0360] It should be understood that embodiment two is for the cross-beam switching of the UE caused by satellite movement, and the target satellite beam and the source satellite beam are in the same satellite network device. This process supports batch switching of multiple terminals, reducing the switching signaling overhead of multiple UEs with per UE as the switching granularity (for example, the following signaling is per UE, and the other broadcast or group signaling / messages / information).

[0361] 1. Refer to step 1 of embodiment one.

[0362] 2. Refer to step 2 of embodiment one. In embodiment two, step 2 is an optional step. If the candidate satellite beams are included in step 4, the satellite network device can not send the first information to the UE.

[0363] 3. The UE and the satellite network device wait for the next time period according to the first information.

[0364] 4. At the beginning of the next time period, the satellite network device can send a switching indication through the source beam (for example, beam 1).

[0365] It should be noted that step 4 is an example of the implementation of the foregoing step A, and the implementation processes of the two steps can be mutually referred.

[0366] Optionally, the switching indication message / signaling / information can indicate N satellite beam information (or first information), and the transmission mode of the N satellite beam information (or first information) can be referred to the implementation process in step 2 of the embodiment.

[0367] Optionally, the switching indication message / signaling / information can include candidate satellite beam information and measurement configuration information of the candidate satellite beam. The candidate satellite beam information and the measurement configuration information of the candidate satellite beam are used for the UE to measure the candidate satellite beam, so as to determine the target satellite beam of the switching. That is, the source satellite network device determines the candidate satellite beam and transmits it in the switching indication.

[0368] Optionally, if the candidate satellite beam information is not included in the switching indication information, the UE determines the candidate satellite beam according to the first information received in step 2. The candidate satellite beam can include one or more beams covering the current position of the UE in the next time period.

[0369] Step 5. The UE measures the candidate beam (such as the candidate satellite beam) and determines the target beam (such as the target satellite beam).

[0370] It should be noted that step 5 is an example of the implementation of the foregoing step S502, and the implementation processes of the two steps can be mutually referred.

[0371] For example, the UE can measure the candidate satellite beam according to the measurement configuration information of each beam of the candidate satellite beam included in the switching indication message / signaling / information in step 4, so as to determine the signal quality of the candidate satellite beam.

[0372] Optionally, if the candidate satellite beam information is not included in the switching indication in step 4, the UE determines the candidate satellite beam by itself and measures the candidate satellite beam. At this time, the UE can not have the measurement configuration information, and therefore, the UE can measure the signal quality of the broadcast signal (such as the synchronization signal / physical broadcast channel block (SSB or S-SS / PSBCH block)). Alternatively, the measurement configuration information of the beam is included in the beam information in the first information, so that the UE can measure the candidate beam according to the measurement configuration information of the beam in the first information.

[0373] In addition, the method for the terminal to determine the target satellite beam can refer to the method for the UE to determine the target satellite beam in step 5 of the embodiment.

[0374] Step 6. The satellite network device starts to buffer the downlink packets.

[0375] For example, the satellite network device starts to buffer the downlink packets after sending the switching indication, or when the next time period is about to arrive or arrives.

[0376] Optionally, the satellite network device can continue to send the buffered packets through the beam 1, which can reduce the switching delay.

[0377] Optionally, in the scenario shown in FIG. 7b, since the target satellite beam and the source satellite beam belong to the same satellite network device, there is no need to forward the data packets.

[0378] Step 7. The UE synchronizes through the target beam.

[0379] For example, the UE can disconnect the connection of the source beam and synchronize uplink through the target satellite beam.

[0380] For example, the UE can initiate a RACH procedure to synchronize uplink. Optionally, to avoid multiple UEs in the coverage of the source beam simultaneously initiating the RACH procedure to cause procedure conflict, the UE can wait for a random time period less than the longest waiting time period before initiating the RACH procedure. The longest waiting time period can be set by pre-configuration or configuration, for example, the indication information of the longest waiting time period can be included in the switching indication message / signaling / information in step 4 or the first information in step 2.

[0381] Step 8. The satellite network device starts to send the buffered data to the UE through the target beam.

[0382] Optionally, after the UE synchronizes with the target beam, the satellite network device can send the data buffered in step 6 to the UE.

[0383] Step 9. The terminal and the satellite network device transceive data through the target beam.

[0384] Please refer to FIG. 7c, which is another schematic diagram of the communication method provided by the present application. For the convenience of later reference, the method shown in FIG. 7c is referred to as embodiment three. In the example shown in FIG. 7c, the first communication device is the UE, the second communication device is the satellite network device 1 (i.e. the network device corresponding to the source beam or the source satellite network device), the third communication device is the satellite network device 2 (i.e. the network device corresponding to the target beam or the target satellite network device), the first network element is different from the source satellite network device, and the core network device includes the second network element and the third network element.

[0385] It should be understood that embodiment three is directed to the cross-beam handover of a UE caused by the movement of a satellite network device, and the target beam and the source beam belong to different satellite network devices. In addition, in embodiment three, the source satellite network device and the target satellite network device can have no interface for direct communication, and the control plane messages of both can be forwarded through the second network element, and the user plane messages (such as buffered data) of both can be forwarded through the third network element.

[0386] Step 1. Same as step 1 of embodiment 2.

[0387] Step 2. Same as step 2 of embodiment 2.

[0388] Step 3. Same as step 3 of embodiment 2.

[0389] Step 4. Same as step 4 of embodiment 2.

[0390] Step 5. Satellite network device 1 sends the UE context to the second network element.

[0391] It should be noted that step 5 is an example of the implementation of the foregoing step D, and the implementation processes of these steps can be mutually referred.

[0392] In this case, the satellite network device 1 can determine the candidate target beam for each UE and send the UE context and the satellite identifier of the corresponding candidate target beam to the second network element, so that the second network element sends the UE context to the candidate target satellite. Optionally, the message can also include information of the candidate target beam corresponding to the UE, such as the identifier of the candidate target beam.

[0393] As an example, the UE context sent by the satellite network device 1 in step 5 can include the context of a batch of UEs (or all UEs) covered by the source beam.

[0394] Taking the scenario shown in FIG. 3b as an example, the UEs under one beam can correspond to the same candidate target beam, at this time, the satellite network device 1 sends the context of all UEs under the beam to the candidate target satellite corresponding to the candidate target beam. When sending the message, since the satellite network device 1 can have no transmission link with the candidate target satellite (for example, satellite network device 2), the satellite network device 1 can first send the context of all UEs under the source beam and the identifier information of the candidate target satellite corresponding to these UEs, the identifier information of the candidate target beam to the second network element, and the second network element sends the UE context to the candidate target satellite.

[0395] For example, in the scenario shown in FIG. 3c, the UEs under the coverage of one beam can correspond to different candidate target beams. At this time, the satellite network device 1 can send the contexts of different groups of UEs to different candidate target satellites corresponding to the candidate target beams. In the specific message sending, the satellite network device 1 can send the contexts of the UEs corresponding to the same candidate target beam together to the candidate target satellite corresponding to the candidate target beam. Since there is no transmission link between the satellite network device 1 and the candidate target satellite (satellite network device 2), the satellite network device 1 first sends a group of UE contexts and the identification information of the candidate target satellite corresponding to the group of UEs and the identification information of the candidate target beam to the second network element, and the second network element sends the group of UE contexts to the candidate target satellite corresponding to the group of UEs.

[0396] Optionally, the UE context sent by the satellite network device 1 in step 5 can be carried in a certain message, and the message can also indicate to establish a forwarding tunnel for forwarding data between the source satellite network device and the target satellite network device.

[0397] Step 6. The second network element sends the UE context to the satellite corresponding to the target beam.

[0398] It should be noted that step 6 is an example of the implementation of the foregoing step E, and the implementation processes of these steps can be mutually referred.

[0399] For example, in step 6, the second network element sends the context of one or all groups of UEs to the candidate target satellite according to the satellite identification of the candidate target beam in step 5.

[0400] Optionally, if the indication to establish a forwarding tunnel is included in step 5, the message can also include the indication to establish a forwarding tunnel.

[0401] Optionally, if the second network element receives the indication to establish a forwarding tunnel, the second network element obtains the forwarding tunnel information of the third network element in the process of selecting the third network element. The forwarding tunnel is a network element level tunnel, which can be an IPinIP tunnel, or an SRv6 or other type of tunnel. According to the different types of tunnels, the tunnel information is also different. For example, for IPinIP and SRv6 tunnels, the tunnel information is the IP address of the third network element. According to the different types of tunnels, the second network element can also need to request the third network element to allocate the forwarding tunnel information, that is, the second network element sends a request message to the third network element to establish a forwarding tunnel, the third network element responds to the message, and sends the allocated tunnel information to the second network element.

[0402] Optionally, if the forwarding tunnel needs to be established, the second network element also sends the forwarding tunnel information of the third network element to the candidate target satellite.

[0403] Step 7. The second network element receives the response message of the candidate target satellite.

[0404] Optionally, if a forwarding tunnel needs to be established, the response message can include the tunnel information of the candidate target satellite.

[0405] Step 8. The second network element informs the third network element to establish a tunnel.

[0406] For example, the second network element informs the user plane network element to establish a forwarding tunnel after receiving the tunnel information of the candidate target satellite. The second network element can send the tunnel information of the candidate target satellite to the third network element, and configure the third network element to forward the data received from the source satellite to the candidate target satellite. Taking IP in IP as an example, the second network element configures the third network element to detect the inner destination address of the data packet (corresponding to the address of the candidate target satellite), and forward the data packet to the candidate target satellite (satellite network device 2 in FIG. 7c) according to the inner destination address. For example, the format of the data packet is shown in Table 4.

[0407] Table 4

[0408] In Table 4, GTP-U represents general packet radio system (GPRS) tunneling protocol-user plane (GPRS tunneling protocol-user plane, GTP-U).

[0409] For example, for a data packet implemented based on Table 4, the third network element can check the inner destination address after receiving the data packet, determine the outer destination address according to the inner destination address, and re-encapsulate the data packet for sending to the destination satellite network device. Optionally, the outer source address of the re-encapsulated data packet is the IP address of the third network element, and the outer destination address is the IP address of the candidate target satellite. Here, the inner and outer destination IP addresses are both the IP address of the candidate target satellite network device, and the two addresses can be the same or different.

[0410] Step 9. The second network element sends a response message to the source satellite network device (i.e., satellite network device 1).

[0411] Optionally, if a forwarding tunnel needs to be established, the response message can include the tunnel information of the candidate target satellite.

[0412] Step 10. The source satellite network device starts to forward data to the third network element.

[0413] Optionally, the source satellite network device forwards data to the third network element according to the tunnel established in the previous steps.

[0414] Optionally, there can be multiple candidate target satellites, in which case multiple forwarding tunnels are established in step 5-9, and the source satellite network device copies the data and forwards the data through the forwarding tunnels corresponding to the multiple candidate target satellites.

[0415] Optionally, in addition to forwarding the downlink data to the candidate target satellite, the source satellite network device can continue to send the data to the UE through the air interface of the source satellite network device. If the air interface between the UE and the source satellite network device still exists at this time, the UE can still receive the data.

[0416] Step 11. The third network element sends data to the candidate target satellite network device according to the tunnel established in step 9.

[0417] Optionally, after receiving the forwarded data, the third network element forwards the data to the candidate target satellite according to the forwarding tunnel established in step 5-9.

[0418] Step 12. The candidate target satellite network device caches the received forwarded data.

[0419] Step 13. See step 5 of embodiment two.

[0420] Step 14. See step 7 of embodiment two.

[0421] Step 15. The target satellite network device sends a user plane path update request to the second network element after determining that the terminal accesses the target satellite beam.

[0422] For example, the user plane path update is used to request the third network element to subsequently send downlink data to the target satellite network device. The message carries the downlink tunnel information of the target satellite network device, which is used to receive the downlink data of the terminal.

[0423] Optionally, this step is a UE-level message, i.e., the message can be only for one UE.

[0424] Step 16. The second network element sends the tunnel information of the target satellite network device to the third network element for updating the downlink path.

[0425] After step 16, the third network element can stop sending data to the source satellite network device and start sending downlink data to the target satellite network device.

[0426] Optionally, after step 14, the target satellite network device sends the forwarded data received from the source satellite network device to the terminal. When performing downlink UE matching, the target satellite network device matches the user context according to the address of the source satellite network device in the inner IP header in the data packet and the TEID allocated by the source satellite network device in the GTP-U header in the inner data packet, so as to send the data to the UE. Specifically, the UE context sent by the source satellite network device includes the IP address of the source satellite network device in the inner IP header and the TEID of the GTP-U in the inner data packet, and the context of the terminal can be matched according to the two information.

[0427] Optionally, after step 16, after the target satellite network device sends all the downlink forwarded data received from the source satellite network device to the terminal, the target satellite network device can start sending the downlink data received from the third network element to the terminal.

[0428] Referring to FIG. 7d, another schematic diagram of the communication method provided by the present application is shown. For ease of reference hereinafter, the method shown in FIG. 7d is referred to as embodiment four. In the example shown in FIG. 7d, the first communication device is a UE, the second communication device is a source satellite network device (i.e., a network device corresponding to a source beam), the third communication device is a target satellite network device (i.e., a network device corresponding to a target beam), the first network element is a device different from the source satellite network device, and the core network device includes a second network element and a third network element.

[0429] It should be understood that embodiment four is a cross-beam handover process caused by UE movement, i.e., the UE moves out of the coverage range of the serving satellite beam of the current time period before the next time period arrives or when the next time period arrives. Embodiment four is described by taking the case where the target satellite beam and the source satellite beam belong to different satellite network devices as an example.

[0430] Step 1. Same as step 1 of embodiment one.

[0431] Step 2. Same as step 2 of embodiment one.

[0432] Step 3. The UE detects that it will soon leave the coverage area of the source beam.

[0433] For example, the UE detects that it will soon leave the coverage area of the source beam immediately before the next time period arrives, or the UE detects that it will soon leave the coverage area of the source beam at the junction time of the two time periods.

[0434] Step 4. The UE determines a candidate target beam and performs measurement on the candidate target beam.

[0435] Optionally, the UE determines the candidate target beam according to the first information received in step 2 and the location information of the UE. Specifically, when the current time is still in the current time period, the UE determines the candidate target beam using the information of the beams serving the adjacent area (i.e., the second geographic area) of the current beam service area in the first information and the location of the UE. The candidate target beam selected by the UE covers the new location of the UE in the current time period.

[0436] Optionally, when the UE finds that the time when it moves out of the coverage area of the source beam is at the junction of two time periods, the UE determines the subsequent target beam using the beam information of the beams covering the adjacent area (i.e., the second geographic area) of the source beam coverage area in the next time period and the location of the UE. The candidate target beam selected by the UE covers the new location of the UE in the next time period.

[0437] Optionally, after determining the candidate target beam, the UE measures the candidate target beam using the information of the candidate target beam, and selects the target beam according to the measurement result. For details, see step 5 of Embodiment 2.

[0438] Step 5. The UE sends a handover request to the source satellite network device, indicating handover to the target beam.

[0439] It should be noted that step 5 is an example of the implementation of the foregoing step B, and the implementation processes of these steps can be mutually referred.

[0440] Optionally, the handover request message / signaling / information can carry the identifier of the target beam and / or the identifier of the satellite cell corresponding to the target beam. If the target beam belongs to another satellite, the handover request message / signaling / information can also carry the identifier of the target satellite corresponding to the target beam.

[0441] Step 6. Handover flow. For example, step 6 can refer to a conventional handover flow (e.g., a cross-base station handover flow).

[0442] Optionally, in another implementation, the UE first determines the candidate target beam and sends the candidate target beam to the base station. Then the source satellite network device configures measurement information for the UE to measure the candidate target beam, and triggers handover according to the measurement result of the candidate target beam reported by the UE.

[0443] Referring to FIG. 8, the embodiment of the present application provides a communication apparatus 800, which comprises a transceiver unit 802 and a processing unit 801.

[0444] It should be understood that the communication device 800 can implement the functions of any one of the first to fourth communication devices in the above method embodiments, and thus can also implement the beneficial effects possessed by the above method embodiments. In the embodiments of the present application, the communication device 800 can be any one of the communication devices in the above method embodiments, or can be an integrated circuit or element inside any one of the communication devices in the above method embodiments, such as a chip.

[0445] In a possible implementation, when the apparatus 800 is configured to perform the method performed by the first communication device in the above method embodiments, the transceiver 802 is configured to receive first information, the first information being used to indicate information of N satellite beams, at least one satellite beam of the N satellite beams having a signal coverage area including a first geographic area in each time period of K time periods, wherein the K time periods are continuous time periods with the same time length, and K and N are positive integers; when the first information is received, a terminal device located in the first geographic area includes a first terminal device; and the processing unit 801 is configured to determine a target satellite beam for communicating with the first terminal device based on the information of the N satellite beams, the target satellite beam being included in the N satellite beams.

[0446] In another possible implementation, when the apparatus 800 is configured to perform the method performed by the second communication device in the above method embodiments, the processing unit 801 is configured to obtain first information, the first information being used to indicate information of N satellite beams, at least one satellite beam of the N satellite beams having a signal coverage area including a first geographic area in each time period of K time periods, wherein the K time periods are continuous time periods with the same time length, and K and N are positive integers; when the first information is received, a terminal device located in the first geographic area includes a first terminal device; and the information of the N satellite beams is used to determine a target satellite beam for communicating with the first terminal device, the target satellite beam being included in the N satellite beams; and the transceiver 802 is configured to send the first information.

[0447] In another possible implementation, when the apparatus 800 is configured to perform the method performed by the third communication device in the above method embodiments, the transceiver 802 is configured to receive fourth information, the fourth information including context information of one or more terminal devices located in a first geographic area, the one or more terminal devices including a first terminal device; and the transceiver 802 is further configured to receive a RACH request message sent by the first terminal device, the context information of the first terminal device being used to switch the first terminal device to a target satellite beam.

[0448] In another possible implementation, when the apparatus 800 is configured to perform the method performed by the fourth communication apparatus in the foregoing embodiments, the transceiver 802 is configured to receive a first message from a source satellite network device, the first message comprising fourth information and an identifier of a target satellite network device, the fourth information comprising context information of one or more terminal devices located in a first geographical area, wherein the source satellite network device is a source satellite network device serving the one or more terminal devices; and the transceiver 802 is further configured to send the fourth information to the target satellite network device.

[0449] It should be noted that the information execution process of the units of the communication apparatus 800 and the corresponding technical effects and the like can be referred to the descriptions of the method embodiments provided in the foregoing embodiments of the present application, and will not be described here.

[0450] Referring to FIG. 9, another schematic structural diagram of a communication apparatus 900 provided in the present application is shown, the communication apparatus 900 at least comprises an input / output interface 901. The communication apparatus 900 can be a chip or an integrated circuit.

[0451] Optionally, the communication apparatus further comprises a logic circuit 902.

[0452] The transceiver 802 shown in FIG. 8 can be a communication interface, which can be the input / output interface 901 in FIG. 9, and the input / output interface 901 can comprise an input interface and an output interface. Alternatively, the communication interface can also be a transceiver circuit, which can comprise an input interface circuit and an output interface circuit.

[0453] Optionally, the input / output interface 901 is configured to receive first information, the first information being used to indicate information of N satellite beams; in each time period of K time periods, a signal coverage area of at least one satellite beam of the N satellite beams comprises a first geographical area; the K time periods are continuous time periods with the same time length, and K and N are positive integers; when the first information is received, a terminal device located in the first geographical area comprises a first terminal device; and the logic circuit 902 is configured to determine a target satellite beam for communicating with the first terminal device based on the information of the N satellite beams, the target satellite beam being included in the N satellite beams.

[0454] Optionally, the logic circuit 902 is configured to acquire first information, the first information being used to indicate information of N satellite beams, a signal coverage area of at least one of the N satellite beams comprising a first geographic area in each of K time periods; the K time periods are continuous time periods with the same time length, and K and N are positive integers; when the first information is received, the terminal device located in the first geographic area comprises a first terminal device; the information of the N satellite beams is used to determine a target satellite beam for communication with the first terminal device, the target satellite beam being included in the N satellite beams; and the input and output interface 901 is configured to send the first information.

[0455] Optionally, the input and output interface 901 is configured to receive fourth information, the fourth information comprising context information of one or more terminal devices located in a first geographic area, the one or more terminal devices comprising the first terminal device; and the input and output interface 901 is further configured to receive a RACH request message sent by the first terminal device, the context information of the first terminal device being used to switch the first terminal device to a target satellite beam.

[0456] Optionally, the input and output interface 901 is configured to receive a first message from a source satellite network device, the first message comprising the fourth information and an identifier of a target satellite network device, the fourth information comprising context information of one or more terminal devices located in a first geographic area; the source satellite network device is a source satellite network device serving the one or more terminal devices; and the input and output interface 901 is further configured to send the fourth information to the target satellite network device.

[0457] The logic circuit 902 and the input and output interface 901 can perform the method executed by any communication device (such as a terminal device or a network device) in the foregoing method embodiments and achieve the corresponding beneficial effects, which will not be described herein again.

[0458] In a possible implementation, the processing unit 801 shown in FIG. 8 can be the logic circuit 902 in FIG. 9.

[0459] Optionally, the logic circuit 902 can be a processing device, and the functions of the processing device can be partially or entirely implemented through software.

[0460] Optionally, the processing device can include a memory and a processor, where the memory is configured to store a computer program, and the processor is configured to read and execute the computer program stored in the memory to perform the corresponding processing and / or steps in any one method embodiment.

[0461] Optionally, the processing device can only include a processor. The memory for storing the computer program is located outside the processing device, and the processor is connected with the memory through the circuit / wire to read and execute the computer program stored in the memory. Among them, the memory and the processor can be integrated together, or they can also be physically independent of each other.

[0462] Optionally, the processing device can be one or more chips, or one or more integrated circuits. For example, the processing device can be one or more field-programmable gate arrays (FPGA), application specific integrated circuits (ASIC), system on chips (SoC), central processor units (CPU), network processors (NP), digital signal processors (DSP), micro controller units (MCU), programmable logic devices (PLD) or other integrated chips, or any combination of the above chips or processors, etc.

[0463] Please refer to FIG. 10, the communication device 1000 involved in the above embodiments provided by the embodiments of the present application, which can be specifically the communication device in the above embodiments as a terminal device.

[0464] Among them, a possible logical structure diagram of the communication device 1000 can include but not limited to at least one processor 1001 and a communication interface 1002.

[0465] Further optionally, the device can also include at least one of a memory 1003, a bus 1004, and in the embodiments of the present application, the at least one processor 1001 is used to control the processing of the actions of the communication device 1000.

[0466] The processor 1001 can be a central processing unit, a general purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array, or other programmable logic device, transistor logic, hardware components, or any combination thereof, which can implement or execute various example logical blocks, modules, and circuits described in connection with the disclosure. The processor can also be a combination of computing functionality, such as a combination of one or more microprocessors, a combination of a digital signal processor and a microprocessor, or the like. For the sake of brevity and clarity, the detailed description of the operation of the system, apparatus, and units described above can be referred to the corresponding processes in the method embodiments described above, and will not be repeated here.

[0467] It should be noted that the communication apparatus 1000 shown in FIG. 10 can be specifically used to implement the steps implemented by the terminal device in the foregoing method embodiments, and achieve the corresponding technical effects of the terminal device. The specific implementation of the communication apparatus shown in FIG. 10 can be referred to the description in the foregoing method embodiments, which will not be repeated here.

[0468] Referring to FIG. 11, FIG. 11 is a structural schematic diagram of a communication apparatus 1100 provided by an embodiment of the present application, which can be specifically a network device in the foregoing embodiments. The structure of the communication apparatus can be referred to the structure shown in FIG. 11.

[0469] The communication apparatus 1100 includes at least one processor 1111 and at least one network interface 1114.

[0470] Optionally, the communication apparatus further includes at least one memory 1112, at least one transceiver 1113, and one or more antennas 1115. The processor 1111, the memory 1112, the transceiver 1113, and the network interface 1114 are connected, for example, through a bus. In the embodiments of the present application, the connection can include various interfaces, transmission lines, or buses, etc., which are not limited in the embodiments of the present application. The antenna 1115 is connected to the transceiver 1113. The network interface 1114 is configured to enable the communication apparatus to communicate with other communication devices through a communication link. For example, the network interface 1114 can include a network interface between the communication apparatus and a core network device, such as an S1 interface. The network interface can include a network interface between the communication apparatus and other communication apparatuses (such as other network devices or core network devices), such as an X2 or Xn interface.

[0471] The processor 1111 is mainly used for processing communication protocols and communication data, controlling the whole communication device, executing software programs, processing data of the software programs, such as for supporting the communication device to perform the actions described in the embodiments. The communication device can include a baseband processor mainly used for processing communication protocols and communication data, and a central processor mainly used for controlling the whole terminal device, executing software programs, and processing data of the software programs. The processor 1111 in FIG. 11 can integrate the functions of the baseband processor and the central processor, and those skilled in the art can understand that the baseband processor and the central processor can also be independent processors interconnected by a bus or the like. Those skilled in the art can understand that the terminal device can include multiple baseband processors to adapt to different network modes, and the terminal device can include multiple central processors to enhance its processing capability, and various components of the terminal device can be connected by various buses. The baseband processor can also be referred to as a baseband processing circuit or a baseband processing chip. The central processor can also be referred to as a central processing circuit or a central processing chip. The function of processing communication protocols and communication data can be built into the processor, or stored in the memory in the form of a software program, and the processor executes the software program to realize the baseband processing function.

[0472] The memory is mainly used for storing software programs and data. The memory 1112 can exist independently and be connected to the processor 1111. Alternatively, the memory 1112 can be integrated with the processor 1111, for example, integrated in a chip. The memory 1112 can store program codes for executing the technical solutions of the embodiments of the present application, and the processor 1111 controls the execution. Various computer programs executed can also be regarded as a driver of the processor 1111.

[0473] FIG. 11 only shows one memory and one processor. In actual terminal devices, there can be multiple processors and multiple memories. The memory can also be referred to as a storage medium or a storage device, etc. The memory can be a storage element on the same chip as the processor, that is, an on-chip storage element, or an independent storage element, and the embodiments of the present application do not limit this.

[0474] The transceiver 1113 can be configured to support the receiving or transmitting of radio frequency signals between the communication device and a terminal. The transceiver 1113 can be connected to the antenna 1115. The transceiver 1113 includes a transmitter Tx and a receiver Rx. Specifically, the one or more antennas 1115 can receive radio frequency signals, the receiver Rx of the transceiver 1113 is configured to receive the radio frequency signals from the antenna and convert the radio frequency signals into digital baseband signals or digital intermediate frequency signals, and provide the digital baseband signals or the digital intermediate frequency signals to the processor 1111 for further processing, such as demodulation processing and decoding processing, of the digital baseband signals or the digital intermediate frequency signals by the processor 1111. In addition, the transmitter Tx in the transceiver 1113 is also configured to receive modulated digital baseband signals or digital intermediate frequency signals from the processor 1111, and convert the modulated digital baseband signals or the digital intermediate frequency signals into radio frequency signals, and transmit the radio frequency signals through the one or more antennas 1115. Specifically, the receiver Rx can selectively perform one or more levels of down-mixing processing and analog-to-digital conversion processing on the radio frequency signals to obtain the digital baseband signals or the digital intermediate frequency signals, and the order of the down-mixing processing and the analog-to-digital conversion processing can be adjustable. The transmitter Tx can selectively perform one or more levels of up-mixing processing and digital-to-analog conversion processing on the modulated digital baseband signals or the digital intermediate frequency signals to obtain the radio frequency signals, and the order of the up-mixing processing and the digital-to-analog conversion processing can be adjustable. The digital baseband signals and the digital intermediate frequency signals can be collectively referred to as digital signals.

[0475] The transceiver 1113 can also be referred to as an interface unit, a transceiving unit, a transceiver, a transceiving device, an interface module, etc. Optionally, the devices in the interface unit for implementing the receiving function can be regarded as a receiving unit, and the devices in the interface unit for implementing the transmitting function can be regarded as a transmitting unit, that is, the interface unit includes the receiving unit and the transmitting unit, the receiving unit can also be referred to as a receiver, an input port, a receiving circuit, etc., and the transmitting unit can be referred to as a transmitter, a transmitter, or a transmitting circuit, etc.

[0476] It should be noted that the communication device 1100 shown in FIG. 11 can be specifically configured to implement the steps implemented by the network device in the foregoing method embodiments, and achieve the corresponding technical effects of the network device. The specific implementation manner of the communication device 1100 shown in FIG. 11 can be referred to the description in the foregoing various method embodiments, which will not be described here one by one.

[0477] The embodiments of the present application also provide a computer readable storage medium for storing one or more computer execution instructions, when the computer execution instructions are executed by a computer, the processor executes the method described in any of the possible implementation manners of the communication device (such as a terminal device or a network device) in the foregoing method embodiments.

[0478] The embodiment of the present application further provides a computer program product (or computer program), including instructions, when the instructions in the computer program product are executed by a processor, the processor executes the method of any possible implementation manner of the communication device (for example, the terminal device or the network device) in the above method embodiment.

[0479] The embodiment of the present application further provides a chip system, including at least one processor, used for implementing the functions involved in the possible implementation manner of the communication device (for example, the terminal device or the network device) in any of the above method embodiments.

[0480] Optionally, the chip system further includes an interface circuit, which provides program instructions and / or data for the at least one processor. In a possible design, the chip system can further include a memory, used for storing necessary program instructions and data of the terminal device. The chip system can be composed of a chip, or can include the chip and other discrete devices.

[0481] In a possible design, the chip system can further include a memory, used for storing necessary program instructions and data of the communication device in any of the above method embodiments. The chip system can be composed of a chip, or can include the chip and other discrete devices.

[0482] The embodiment of the present application further provides a communication system, and the network system architecture includes the terminal device and the network device in any of the above embodiments. For example, the terminal device can include a first terminal device, and the network device can include a source satellite network device. Optionally, the network device can further include one or more of the first network element, a target satellite network device or a core network device.

[0483] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented by other manners. For example, the above-described device embodiment is illustrative, for example, the division of the units is a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed units can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0484] The units described as separate components can or can not be physically separate, and the components displayed as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. According to actual needs, part or all of the units can be selected to achieve the purpose of the embodiment scheme.

[0485] In addition, each function unit in each embodiment of the present application can be integrated in one processing module, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software function unit. When the integrated unit is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application essentially contribute to or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0486] The above is only a specific implementation of the embodiments of the present application, but the protection scope of the embodiments of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the embodiments of the present application, which should be covered within the protection scope of the embodiments of the present application. Therefore, the protection scope of the embodiments of the present application should be subject to the protection scope of the claims.

Claims

1. A communication method characterized by comprising: The method comprises: receiving first information, the first information being used for indicating information of N satellite beams; in each time period of K time periods, a signal coverage area of at least one satellite beam of the N satellite beams comprises a first geographic area; wherein the K time periods are continuous time periods with the same time length, K and N are positive integers; when the first information is received, a terminal device located in the first geographic area comprises a first terminal device; determining a target satellite beam for communicating with the first terminal device based on the information of the N satellite beams, the target satellite beam being contained in the N satellite beams.

2. The method of claim 1, wherein, In each time period of the K time periods, a signal coverage area of at least one satellite beam of the N satellite beams comprises a second geographic area, the first geographic area and the second geographic area being adjacent.

3. The method according to claim 1 or 2, characterized in that, The determining of the target satellite beam for communicating with the first terminal device based on the information of the N satellite beams comprises: determining M satellite beams in the N satellite beams based on the information of the N satellite beams, the M satellite beams being used for determining the target satellite beam; wherein a signal coverage area of any satellite beam of the M satellite beams contains a geographic area where the first terminal device is currently located, the geographic area where the first terminal device is currently located being contained in the first geographic area or the second geographic area, M being less than or equal to N.

4. The method of claim 3, wherein, The method further comprises: receiving at least one signal of part or all of the M satellite beams, a measurement result of the at least one signal being used for determining the target satellite beam in the M satellite beams.

5. The method according to any one of claims 1 to 4, characterized in that, The information of the satellite beam comprises at least one of the following: information of a satellite corresponding to the satellite beam, communication frequency information of the satellite beam, information of a cell corresponding to the satellite beam, geographic area information covered by the satellite beam, or service time information of the satellite beam.

6. The method according to any one of claims 1 to 5, characterized in that, The method further comprises: receiving a first signal of the target satellite beam, the first signal being used for synchronization; wherein the first terminal device camps on a target satellite cell or a target satellite network device corresponding to the target satellite beam; or, performing a random access channel (RACH) procedure through the target beam.

7. The method of claim 6, wherein, A receiving time or a sending time of the first information is located in a first time period; the performing of the RACH procedure through the target beam comprises any of the following: performing the RACH procedure through the target beam at a start time of a next time period of the first time period; or, delaying the performing of the RACH procedure through the target beam for a first time length after the start time of the next time period of the first time period, a number of time units contained in the first time length being determined based on a random number, and the number of time units contained in the first time length being less than or equal to a threshold.

8. The method of claim 6, wherein, The method further comprises: receiving second information, the second information being used for indicating a source satellite beam connected by the first terminal device; the performing of the RACH procedure through the target beam comprises any of the following: performing the RACH procedure through the target beam immediately after receiving the second information; or delaying the RACH procedure through the target beam for a second time period after receiving the second information, a quantity of time units included in the second time period being determined based on a random number, and the quantity of time units included in the second time period being less than or equal to a threshold value.

9. The method according to any one of claims 1 to 6, characterized in that, The method further includes: sending third information, the third information being used to request switching the first terminal device from a source satellite beam to the target satellite beam.

10. The method according to any one of claims 1 to 9, characterized in that, The first information is carried in a multicast message or a broadcast message.

11. The method according to any one of claims 8 to 10, characterized in that, The second information is carried in a multicast message or a broadcast message.

12. A communication method characterized by comprising: comprising: obtaining first information, the first information being used to indicate information of N satellite beams, in each time period of K time periods, a signal coverage area of at least one satellite beam of the N satellite beams including a first geographic area; wherein the K time periods are consecutive time periods with the same time length, K and N are positive integers; when the first information is received, a terminal device located in the first geographic area includes a first terminal device; the information of the N satellite beams is used to determine a target satellite beam for communicating with the first terminal device, the target satellite beam being included in the N satellite beams; sending the first information.

13. The method of claim 12, wherein, The N satellite beams correspond to one or more satellite network devices, and the information of the N satellite beams is determined based on ephemeris information of the one or more satellite network devices and / or topology information of the one or more satellite network devices.

14. The method according to claim 12 or 13, characterized in that, The obtaining first information comprises: receiving the first information.

15. The method of any one of claims 12 to 14, characterized in that, The method further includes: sending second information, the second information being used to indicate switching a source satellite beam connected by the first terminal device; or, The first information is further used to indicate switching a source satellite beam connected by the first terminal device.

16. The method according to any one of claims 12 to 15, characterized in that, The method further includes: receiving third information, the third information being used to request switching the first terminal device from a source satellite beam to the target satellite beam.

17. The method according to any one of claims 12 to 16, characterized in that, The method further includes: determining P candidate satellite beams from the N satellite beams, P being less than or equal to N; sending fourth information to one or more satellite network devices corresponding to the P satellite beams, the fourth information including context information of one or more terminal devices located in the first geographic area.

18. The method of claim 17, wherein, The method further includes: receiving first tunnel information, the first tunnel information being used to receive data packets of one or more terminal devices located in the first geographic area and forwarded by a source satellite network device corresponding to a source satellite beam; forwarding data packets of one or more terminal devices located in the first geographic area based on the first tunnel information, and / or sending data packets cached for the one or more terminal devices through the first tunnel information.

19. The method according to any one of claims 16 to 18, characterized in that, The context information of the one or more terminal devices comprises second tunnel information allocated by the source satellite network device, the second tunnel information being used to determine a radio bearer and / or a session of the one or more terminal devices corresponding to the received downlink data packet, the radio bearer and / or the session being used to transmit the downlink data packet of the one or more terminal devices.

20. A method of communication, comprising: Comprising: receiving fourth information, the fourth information comprising context information of one or more terminal devices located in a first geographical area, the one or more terminal devices comprising a first terminal device; receiving a RACH request message sent by the first terminal device, the context information of the first terminal device being used to switch the first terminal device to a target satellite beam.

21. The method of claim 20, wherein, The method further comprises: sending first tunnel information, the first tunnel information being used to receive data packets of one or more terminal devices located in the first geographical area and forwarded by a source satellite network device; receiving data packets of one or more terminal devices located in the first geographical area based on the first tunnel information.

22. The method of claim 20 or 21, wherein, The data packets of one or more terminal devices located in the first geographical area and forwarded by the source satellite network device comprise data packets of the first terminal device, the method further comprises: after determining that the first terminal device successfully performs a RACH procedure, sending the data packets of the first terminal device to the first terminal device.

23. The method of claim 22, wherein, The context information of the first terminal device comprises second tunnel information allocated by a source satellite network device, the method further comprises: determining a radio bearer or a session of the first terminal device according to the second tunnel information and a data packet header forwarded by the source satellite network device, the radio bearer or the session being used to transmit the data packets of the first terminal device.

24. A method of communication, comprising: Comprising: receiving a first message from a source satellite network device, the first message comprising fourth information and an identifier of a target satellite network device, the fourth information comprising context information of one or more terminal devices located in a first geographical area; wherein the source satellite network device is a source satellite network device serving the one or more terminal devices; sending the fourth information to the target satellite network device.

25. The method of claim 24, wherein, The method further comprises: receiving fifth information from the target satellite network device, the fifth information indicating tunnel information of the target satellite network device, the tunnel information of the target satellite network device being used for the target satellite network device to receive forwarded data of the one or more terminal devices; establishing a tunnel between the target satellite network device corresponding to the target satellite beam and the source satellite network device based on the tunnel information of the target satellite network device.

26. A communications device, characterized by Comprising at least one processor; the at least one processor is coupled with at least one memory; the at least one processor is used to execute the method as claimed in any one of claims 1 to 25.

27. A chip or chip system, characterized by Comprising at least one processor, the at least one processor being used to implement the method as claimed in any one of claims 1 to 25.

28. A readable storage medium characterized by, The storage medium has stored therein computer programs or instructions, which, when executed by a communication device, implement the method of any one of claims 1-25.

29. A computer program product, characterised in that, The computer programs or instructions, when executed by a communication device, implement the method of any one of claims 1-25.

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