Communication method and related device

Abstract

According to a communication method and related devices, first information received by a first communication device is used for indicating information of N satellite beams, and the first communication device can determine a target satellite beam communicating with a first terminal device based on the information of the N satellite beams. Wherein in each of the K time periods, a signal coverage area of at least one satellite beam in the N satellite beams comprises a first geographic area, and when the first communication device receives the first information, the 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 the 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 the target satellite beam based on the first information, and the transmission overhead can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of communication, and in particular, to a communication method and related apparatus. BACKGROUND

[0002] Wireless communication can be transmission communication between two or more communication devices without propagation through a conductor or cable. The communication devices generally include network devices and terminal devices. A conventional network device can be a device fixed on the ground, such as a ground base station of a terrestrial network (TN) cell.

[0003] With the development of communication technology, a network device can not be fixed on the ground. For example, the network device can be a high-speed mobile device, such as a satellite device of a non-terrestrial network (NTN) cell, including but not limited to a low-orbit satellite, a medium-orbit satellite, and a high-orbit satellite.

[0004] Generally, in a beam-based communication mode between a terminal device and a network device, unlike a ground base station of a TN cell, a satellite device of an NTN cell can move at a high speed. As a result, a satellite beam used by the terminal device can change frequently. The changed satellite beam can be referred to as a target satellite beam.

[0005] 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 sharply increase signaling overhead, and further increase power consumption of the terminal device. SUMMARY

[0006] The present application provides a communication method and related apparatus, which can reduce signaling overhead and reduce power consumption of a communication device.

[0007] A first aspect of the present application provides a communication method. The method is applied to a first communication apparatus, for example, the method is executed by the first communication apparatus. The first communication apparatus can be a communication device (such as a first terminal device), or the first communication apparatus can be a part of the communication device (such as a circuit or a chip responsible for communication functions (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), etc.), or the first communication apparatus can also be a logic module or software capable of realizing all or part of the functions of the communication device.

[0008] In the method, a first communication device receives 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 receiving the first information, a terminal device located in the first geographic area comprises 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, the target satellite beam being included in the N satellite beams.

[0009] Based on the above scheme, the first information received by the first communication device is 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 of the N satellite beams comprises a first geographic area, and when the first communication device 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 enable faster search for a target satellite beam based on the first information, thereby reducing power consumption of the one or more terminal devices and improving communication efficiency.

[0010] 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 to traditional techniques, thereby enabling the terminal device to quickly access a target satellite beam in a low-orbit satellite fast-moving scenario and reducing high power consumption of the terminal device caused by blind search for a satellite beam.

[0011] 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.

[0012] It should be understood that the signal coverage area of a satellite beam can be understood as a geographical area in which the signal of the satellite beam is reachable / servable / available for communication. For example, the signal coverage area of a satellite beam can include one or more geographical areas in which terminal devices located in the one or more geographical areas are able to communicate through the satellite beam.

[0013] Optionally, 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.

[0014] It should be understood that the K time periods are consecutive time periods with the same duration, which can be understood as the K time periods being connected at both ends and each time period having the same duration; or the terminal time of the k(th) time period (k is an integer from 1 to K-1) of the K time periods being 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 being the terminal time of the (k-1)(th) time period of the K time periods; or the last time unit of the k(th) time period (k is an integer from 1 to K-1) of the K time periods being adjacent to the starting 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.

[0015] Optionally, the time period can be replaced by other terms, such as a time slice, or a time block, etc.

[0016] Optionally, the information of the N satellite beams can be referred to as auxiliary information of the N satellite beams.

[0017] In a possible implementation of the first aspect, 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 a second geographical area, and the first geographical area is adjacent to the second geographical area. Accordingly, when the first terminal device moves from the first geographical area to the second geographical area, the first terminal device can determine the target satellite beam according to the information of the at least one satellite beam whose coverage area includes the second geographical area in any time period of the K time periods. In this way, after the first terminal device moves from the first geographical area to the second geographical area, the target satellite beam can still be determined by using the first information, so as to maintain the continuity of communication. Compared with the terminal device blindly searching for a satellite and a satellite beam without the first information in any time period of the K time periods, the time delay of the satellite and the cell search can be greatly reduced, so as to reduce the service time delay, improve the service experience, and reduce the power consumption of the terminal device, so as to improve the communication efficiency.

[0018] It should be noted that the first geographical area and the second geographical area can have a partially overlapping area, or can have no overlapping area, which is not limited herein.

[0019] 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 one of the M satellite beams has a signal coverage area containing a geographical area where the first terminal device currently locates, the geographical area where the first terminal device currently locates being contained in the first geographical area or the second geographical area, and M being less than or equal to N.

[0020] Based on the above scheme, the first communication device can determine M satellite beams from the N satellite beams, i.e., the M satellite beams can be candidate satellite beams. Moreover, any one of the M satellite beams has a signal coverage area containing a geographical 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 geographical area where the first terminal device currently locates, and can realize fast determination of the target satellite beam while avoiding the situation of communication failure caused by determining a satellite beam whose signal coverage area does not contain the geographical area where the first terminal device currently locates as the target satellite beam.

[0021] Optionally, in the case that the first terminal device moves or remains stationary in the first geographical area, the geographical area where the first terminal device currently locates is contained in the first geographical area.

[0022] Optionally, in the case that the first terminal device moves from the first geographical area to the second geographical area, the geographical area where the first terminal device currently locates is contained in the second geographical area.

[0023] In a possible implementation of the first aspect, in the N satellite beams, the M satellite beams serve the geographical area where the first terminal device currently locates for a time length greater than or equal to a time length for which the other N-M satellite beams serve the geographical area where the first terminal device currently locates.

[0024] Based on the above scheme, in the N satellite beams, the M satellite beams serving as candidate beams serve the geographical area where the first terminal device currently locates for a longer time length, and in this way, the first communication device can select the M satellite beams serving for a longer time length as candidate beams, and can select the satellite beam serving for a longer time length as the target communication beam as much as possible, so as to reduce the frequency of re-determining the target satellite beam (e.g., beam switching / beam reselection), and further reduce the communication overhead.

[0025] Optionally, the time length during which the satellite beam serves the geographic area can be understood as a service time length during which the satellite beam serves the geographic 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.

[0026] In a possible implementation of the first aspect, the method further includes: receiving, by the first communication device, at least one signal from part or all of the M satellite beams, and performing measurement on the at least one signal to obtain a measurement result for determining the target satellite beam from the M satellite beams.

[0027] Based on the above scheme, the first communication device can further receive at least one signal from part or all of the M satellite beams, and perform measurement 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.

[0028] Optionally, the measurement result can be used to represent the signal quality, for example, the measurement result can include one or more of reference signal receiving power (RSRP), reference signal receiving quality (RSRQ), signal and interference plus noise ratio (SINR), or other parameters.

[0029] 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, information of a cell corresponding to the satellite beam, information of a geographic area covered by the satellite beam, or service time information of the satellite beam.

[0030] Based on the above scheme, the information of the satellite beam can include the at least one described above, so as to improve the flexibility of the scheme implementation.

[0031] 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.

[0032] For another example, the communication frequency information of the satellite beam can indicate a communication frequency corresponding to the satellite beam, for example, the communication frequency information of the satellite beam can include a starting frequency point and / or a terminal frequency point of the communication frequency, or the communication frequency information of the satellite beam can include an index corresponding to the communication frequency.

[0033] For another example, the cell information corresponding to the satellite beam can indicate a 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), a physical cell identifier (PCI) or other information of the cell.

[0034] For another example, the geographic area information covered by the satellite beam can be understood as geographic area information of a signal coverage range of the satellite beam. For example, the geographic area information covered by the satellite beam can indicate one or more geographic areas included in the signal coverage range of the satellite beam, or the geographic area information covered by the satellite beam can also be identifier information of a ground fixed cell / area.

[0035] For another example, the service time information of the satellite beam can indicate one or more of starting time information (for example, a starting moment or a starting time unit), a duration, and terminal time information (for example, a terminal moment or a terminal time unit) of service provided by the satellite beam. For example, the service time of the satellite beam refers to a time when the satellite beam serves a geographic area covered by the satellite beam and included in the information of the satellite beam.

[0036] In a possible implementation manner of the first aspect, the method further includes: the first communication device receives a first signal of the target satellite beam, and the first signal is used for synchronization; and the first terminal device camps on a target satellite cell (or a target satellite network device) corresponding to the target satellite beam; or the first communication device performs a random access channel (RACH) procedure through the target beam.

[0037] Optionally, the first communication device performing the RACH procedure through the target beam includes: the first communication device sending a RACH request message through the target beam.

[0038] Based on the above scheme, the first communication device can receive a first signal of a 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 based on the target satellite beam obtaining 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 terminal device camping 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.

[0039] Alternatively, the first communication device can perform a RACH procedure through the target beam, so that the first terminal device can be switched from the source network device to a target satellite network device corresponding to the target satellite beam. Optionally, in the case that 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.

[0040] Optionally, when the first terminal device receives the first information, the first terminal device can be in RRC_IDLE or RRC_INACTIVE. The first terminal device can camp on the source cell. Alternatively, when the first terminal device receives the first information, 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. The source cell can be a TN cell, that is, the network device corresponding to the source cell can be a TN network device, or 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.

[0041] In a possible implementation of the first aspect, the receiving time or the sending time of the first information is located in a first time period (the first time period can be any one of K time periods); and the first communication device performs the RACH procedure through the target beam includes any one of the following:

[0042] The first communication device performs the RACH procedure through the target beam at a starting time (or a starting time point) of a next time period of the first time period; or

[0043] The first communication apparatus performs the RACH procedure through the target beam after a start time (or a start moment) of a next time period of the first time period by a first time length, a number of time units included in the first time length is determined based on the random number, and the number of time units included in the first time length is less than or equal to a threshold value.

[0044] 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. Moreover, in the case where the first communication apparatus performs the RACH procedure based on the first time length, since the number of time units included in the first time length is determined based on the 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, thereby improving communication efficiency.

[0045] In a possible implementation form of the first aspect, the method further includes: receiving, by the first communication apparatus, second information, the second information being used to indicate switching of a source satellite beam to which the first terminal device is connected; and performing, by the first communication apparatus, the RACH procedure through the target beam includes any of the following:

[0046] performing, by the first communication apparatus, the RACH procedure through the target beam immediately after receiving the second information; or

[0047] performing, by the first communication apparatus, the RACH procedure through the target beam after receiving the second information by a second time length, a number of time units included in the second time length being determined based on the random number, and the number of time units included in the second time length being less than or equal to a threshold value.

[0048] 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. Moreover, in the case where the first communication apparatus performs the RACH procedure based on the second time length, since the number of time units included in the second time length is determined based on the 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, thereby improving communication efficiency.

[0049] Optionally, the second information is transmitted through broadcasting or groupcasting, and the second information is used to indicate the source satellite beam to which one or more terminal devices (including the first terminal device) located in a same geographical area (for example, the first geographical area) are connected, so that the second information can be used to indicate the batch switching of the one or more terminal devices in the same geographical area, thereby reducing the overhead.

[0050] In a possible implementation of the first aspect, the first information is further used to indicate the source satellite beam to which the first terminal device is connected.

[0051] According to the above scheme, in addition to the information used to indicate the N satellite beams, the first information can be used to indicate the source satellite beam to which the first terminal device is connected, so that the first information can be used to indicate more information, thereby reducing the overhead.

[0052] Optionally, the first information is further used to indicate the source satellite beam to which one or more terminal devices (including the first terminal device) located in a same geographical area (for example, the first geographical area) are connected, so that the first information can be used to indicate the batch switching of the one or more terminal devices in the same geographical area, thereby reducing the overhead.

[0053] In a possible implementation of the first aspect, the method further includes: the first communication device sending third information, the third information being used to request switching the first terminal device from a source satellite beam to a target satellite beam.

[0054] According to the above scheme, when the first communication device moves from the first geographical area to a second geographical area, the first communication device can further send third information used to request switching the first terminal device from a source satellite beam to a target satellite beam, so that a receiver of the third information can initiate a switching process of the first terminal device based on the request, thereby realizing the switching of the satellite cell or the satellite network device to which the first terminal device is connected.

[0055] Optionally, the third information includes 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 a target satellite cell or a target satellite network device corresponding to the target satellite beam based on the identifier.

[0056] In a possible implementation of the first aspect, the first information is carried in a groupcast message or a broadcast message.

[0057] According to the above scheme, the first information received by the first communication device can be carried in a groupcast message or a broadcast message, so that one or more terminal devices can obtain the first information through the groupcast message or the broadcast message, thereby reducing the transmission overhead of the information of the satellite beam.

[0058] In a possible implementation of the first aspect, the second information is carried in a multicast message or a broadcast message.

[0059] 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 transmitted 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.

[0060] 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.

[0061] In the method, the second communication device obtains 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 includes 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 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; and the second communication device transmits the first information.

[0062] Based on the above scheme, the first information transmitted by the second communication device is used to indicate information of N satellite beams, so that the receiver of the first information 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 of the N satellite beams includes a first geographic area, and when the receiver 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, the transmission overhead can be reduced, 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 the communication efficiency.

[0063] In addition, in each of the K time periods, the signal coverage area of at least one of the N satellite beams includes the first geographic region. For a terminal device located in the first geographic region (e.g., the first terminal device), the terminal device can determine a target satellite beam according to the satellite beam information of any one of the K time periods, thereby solving the problem that the terminal device cannot obtain a satellite beam serving a geographic region 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.

[0064] 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 corresponding to the one or more satellite network devices. The topology information of the constellation indicates a deployment of the satellites in the constellation, and the position and the speed of each satellite in the constellation at any time can be determined based on the topology information of the satellites. 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 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 geographic region) and a staring time of the satellite beam, and a physical cell identifier corresponding to the satellite beam.

[0065] It should be noted that the frequency used by the satellite beam can be related to the geographic region served by the satellite beam, for example, different frequencies are used when the same satellite beam of the same satellite serves different geographic regions. The frequency used by the satellite beam can also be independent of the geographic region served by the satellite beam, i.e., the same frequency is used by the satellite beam when serving any geographic region. The staring time period and the staring time of the 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 region at time t1, and change the ground region they stare at with a period T. The staring time period and the staring time of the satellite beam can also be configured for each satellite, i.e., the staring time period and the staring time of the satellite beams of different satellites can be different.

[0066] As an example, the second communication device can be a first network element or a part of the first network element, and 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 scheme, the second communication device can send the first information to a network device (for example, a source satellite network device), or the second communication device can send the first information to a terminal device (for example, one or more terminal devices located in the first geographic area), or the second communication device can send the first information to a terminal device (for example, one or more terminal devices located in the first geographic area) through a network device (for example, a source satellite network device).

[0067] As another example, the second communication device can be a source network device (for example, a source satellite network device) or a part of the source network device, and 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 terminal device (for example, one or more terminal devices located in the first geographic area).

[0068] Optionally, the second communication device can obtain 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 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.

[0069] 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.

[0070] 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 being further used to indicate switching of the source satellite beam to which the first terminal device is connected.

[0071] Based on the above scheme, the second communication device can indicate switching of a 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 the switching.

[0072] 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 geographical region (e.g., the first geographical region or the second geographical 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 in the same geographical region, so as to reduce overhead.

[0073] In a possible implementation of the second aspect, the method further includes: starting, by the second communication device, buffering of data packets of the one or more terminal devices located in the first geographical region after the first information or the second information is sent.

[0074] Based on the above scheme, after the first information or the second information is sent, the second communication device can determine that switching of the one or more terminal devices located in the first geographical region will be likely to occur, for this purpose, the second communication device can start buffering of data packets of the one or more terminal devices located in the first geographical region, so that the target satellite network device after switching can obtain the data packets buffered by the second communication device, to prevent or reduce the occurrence of packet loss during terminal cross-satellite beam switching, and to improve service continuity.

[0075] Optionally, after the first information or the second information is sent, the second communication device can buffer the data packets of the one or more terminal devices located in the first geographical region in various ways.

[0076] For example, after the first information or the second information is sent or at the start time of the next time period of the above-mentioned first time period, the second communication device immediately starts buffering of the data packets of the one or more terminal devices located in the first geographical region.

[0077] In a possible implementation of the second aspect, the method further includes: receiving, by the second communication device, 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.

[0078] Based on the above scheme, the second communication device can also receive third information used to request switching of the first terminal device from a source satellite beam to a target satellite beam, so that the second communication device can perform RACH procedures of the first terminal device based on the request, to realize switching of a satellite cell or a satellite network device to which the first terminal device is connected.

[0079] In a possible implementation of the second aspect, 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; 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.

[0080] 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 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.

[0081] 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. Moreover, the signal coverage area of any satellite beam from the P satellite beams contains 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 target satellite beam whose signal coverage area does not contain the geographic region where the first terminal device is currently located, thereby reducing signaling overhead.

[0082] 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 to receive data packets of one or more terminal devices located in the first geographic region and forwarded by a source satellite network device corresponding to a source satellite beam; and forwarding, by the second communication device, the data packets of the one or more terminal devices located in the first geographic region based on the first tunnel information, and / or sending, by the second communication device, data packets cached for the one or more terminal devices through the first tunnel information.

[0083] Based on the above scheme, 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 region 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 devices perform handover, thereby improving service continuity.

[0084] 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.

[0085] In a possible implementation manner 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 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.

[0086] 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 packet of the terminal device based on the determined radio bearer or session, to improve service continuity.

[0087] The third aspect of the present application provides a communication method, which is applied to a third communication device, such as being executed by the third communication device. The third communication device can be a communication device (such as a target satellite network device), or the third communication device can be part of a component (for example, 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 third communication device can also be a logic module or software capable of realizing all or part of the functions of the communication device.

[0088] In the method, the third communication device receives 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; 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.

[0089] 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 geographic area, and after the third communication device receives a RACH request message sent by a first terminal device of 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 and also avoid or reduce the occurrence of service discontinuity.

[0090] 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.

[0091] 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 to the core network device, the first message including the fourth information and an identifier of the target satellite network device, and thereafter, the core network device sends the fourth information to the third communication device based on the first message.

[0092] In a possible implementation manner of the third aspect, the method further includes: the third communication device sending 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; and the third communication device receiving the data packets of the one or more terminal devices located in the first geographic area based on the first tunnel information.

[0093] Based on the above scheme, the third communication device can further send the first tunnel information, so that a receiver (for example, the second communication device) of the first tunnel information sends 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 third communication device can subsequently transmit the associated data packets after the terminal device switches, to improve service continuity.

[0094] In a possible implementation manner of the third aspect, the method further includes: the third communication device buffering the received data packets of the one or more terminal devices located in the first geographic area and forwarded by the source satellite network device.

[0095] Based on the above scheme, the third communication device can further buffer the received data packets of the 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 buffered data packets after the one or more terminal devices switch to the target satellite beam, to improve service continuity.

[0096] Optionally, the buffered data packets comprise data packets of the first terminal device, and the method further comprises: after determining that the first terminal device successfully performs the RACH procedure, the third communication apparatus sends the buffered data packets to the first terminal device.

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

[0098] In a possible implementation manner of the third aspect, the context information of the first terminal device comprises second tunnel information allocated by the source satellite network device, and the method further comprises: the third communication apparatus determines a radio bearer or a session of the first terminal device according to the second tunnel information and a data packet header of the data packets forwarded by the source satellite network device, and the radio bearer or the session is used to transmit the data packets of the first terminal device.

[0099] Based on the above scheme, the fourth information received by the third communication apparatus can comprise second tunnel information allocated by the source satellite network device, so that the 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, so as to improve service continuity.

[0100] In a possible implementation manner of the third aspect, the context information of the one or more terminal devices comprises context information of a second terminal device, and the method further comprises: the third communication apparatus 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.

[0101] 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 not be likely to switch to the third communication apparatus, and therefore, the third communication apparatus can release the context information of the second terminal device, so as to save storage overhead.

[0102] 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 comprises: if data packets forwarded from the source satellite network device are buffered for the second terminal device, the third communication apparatus releases the data packets buffered for the second terminal device.

[0103] 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 buffered data packets for the second terminal device forwarded from the source satellite network device, so as to save storage overhead.

[0104] In a possible implementation of the third aspect, the method further includes: the third communication apparatus sending fifth information, the fifth information indicating tunnel information of a target satellite network device corresponding to the target satellite beam, the tunnel information of the target satellite network device being used for the target satellite network device to receive the forwarded data of the one or more terminal devices.

[0105] 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 the 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, so as 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.

[0106] The fourth aspect of the present application provides a communication method, which is applied to a fourth communication apparatus, such as being executed by the fourth communication apparatus. The fourth communication apparatus can be a communication device (e.g., a core network device), or the fourth communication apparatus can be part of a 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 apparatus can also be a logic module or software capable of realizing all or part of the functions of the communication device.

[0107] In the method, the fourth communication apparatus receives a first message from a source satellite network device, the first message including fourth information and an identifier of a target satellite network device, the fourth information including 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 fourth communication apparatus sends the fourth information to the target satellite network device.

[0108] Based on the above scheme, after receiving 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.

[0109] In a possible implementation form of the fourth aspect, the method further includes: receiving, by the fourth communication device, 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 the forwarding data of the one or more terminal devices; and establishing, by the fourth communication device, 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.

[0110] 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.

[0111] 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: obtaining, by the fourth communication device, tunnel information of a first network element, the tunnel information of the first network element being used for receiving the forwarding data of the one or more terminal devices from the source satellite network device; and sending, by the fourth communication device, 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.

[0112] The fifth aspect of the present application provides a communication device, comprising 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 time 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 included in the N satellite beams.

[0113] 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.

[0114] The sixth aspect of the present application provides a communication device, comprising a transceiver unit and a processing unit; the processing unit is configured to obtain 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 time 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 included in the N satellite beams; the transceiver unit is configured to send the first information.

[0115] 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.

[0116] The seventh aspect of the present application provides a communication device, comprising a transceiver unit; the transceiver unit 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 a first terminal device; the transceiver unit is also 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.

[0117] In the seventh 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 third aspect and achieve the corresponding technical effects, which can be referred to the third aspect for details and will not be described here.

[0118] The eighth aspect of the present application provides a communication apparatus, comprising a transceiver 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 is further configured to send the fourth information to the target satellite network device.

[0119] In the eighth aspect of the present application, the constituent modules of the communication apparatus 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 and will not be described here in detail.

[0120] The ninth aspect of the present application provides a communication apparatus, comprising at least one processor configured to execute computer programs or instructions to enable the apparatus to implement the method of any one of the first aspect to the fourth aspect and any one of the possible implementation manners thereof.

[0121] Optionally, the at least one memory is coupled with the memory, and the memory is configured to store the computer programs or instructions.

[0122] Optionally, the communication apparatus comprises the memory.

[0123] The tenth aspect of the present application provides a communication apparatus, 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.

[0124] The eleventh aspect of the present application provides a communication system, comprising the first communication apparatus and the second communication apparatus.

[0125] Optionally, the communication system further comprises the third communication apparatus and / or the fourth communication apparatus.

[0126] The twelfth aspect of the present application provides a computer readable storage medium, the storage medium being configured to store one or more computer execution instructions, when the computer execution instructions are executed by a processor, the processor executes the method as described in any one of the possible implementation manners of any one of the first aspect to the fourth aspect.

[0127] 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 a processor, the processor executes the method as described in any one of the possible implementation manners of any one of the first aspect to the fourth aspect.

[0128] The fourteenth aspect of the present application provides a chip or a chip system, which comprises at least one processor for supporting 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.

[0129] In a possible design, the chip or the chip system can further comprise a memory for storing 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 for providing program instructions and / or data for the at least one processor.

[0130] 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

[0131] Figure 1 A schematic diagram of a communication system provided in the present application;

[0132] Figures 2a to 2e Some schematic diagrams of a satellite communication process provided in the present application;

[0133] Figures 3a to 3c Some other schematic diagrams of a satellite communication process provided in the present application;

[0134] Figure 4 A schematic diagram of a satellite communication process in a 5G system provided in the present application;

[0135] Figure 5 And Figure 6 Some schematic diagrams of a communication method provided in the present application;

[0136] Figures 7a to 7d Some other schematic diagrams of a communication method provided in the present application;

[0137] Figures 8 to 11 Some schematic diagrams of a communication device provided in the present application. DETAILED DESCRIPTION

[0138] First, some terms in the embodiments of the present application are explained to facilitate understanding of the skilled in the art.

[0139] (1) Terminal device: can be a wireless terminal device capable of receiving network device scheduling and indication information, and 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.

[0140] 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, computer-built-in 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 the relevant communication functions in the device, or a communication platform that can include a radio frequency (RF) part, etc.

[0141] (2) Network device: can be a device in a wireless network, for example, the network device can be a RAN node (or device) that accesses the terminal device to the wireless network, which can also be called 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.

[0142] 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).

[0143] In another possible scenario, multiple RAN nodes cooperate to assist a terminal 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).

[0144] 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.

[0145] 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.

[0146] 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.

[0147] Table 1

[0148] ORAN network elements Protocol layer functions of 3GPP O-CU-CP RRC+PDCP - Control Plane (PDCP-C) O-CU-UP SDAP+PDCP - User Plane (PDCP-U) O-DU RLC+MAC+PHY-high O-RU PHY-low

[0149] The network device can be other devices that provide wireless communication functions for terminal devices. 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 further include a core network device, for example, including a mobility management entity (MME) in a 4th 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), a network element such as an access and mobility management function (AMF), a user plane function (UPF), or a session management function (SMF) in a 5G network. 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 described above can also be a network node with artificial intelligence (AI) capability, which can provide AI services for terminals or other network devices. For example, it can be an AI node, a computing power node, an RAN node with AI capability, a core network element with AI capability, 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, the base station can be deployed on a satellite as a whole, 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 is deployed on a satellite, and other parts are deployed on the ground, for another example, the RU and the DU of the base station are deployed on a satellite, and the CU is deployed on the ground. Similarly, the core network device can also be deployed on a satellite. For example, part of the user plane network element 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 element of the core network can also be deployed on a satellite, for example, the mobility management network element and the session management network element are deployed on a satellite, which can 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 at the same time. Configuration refers to that the network device sends some parameter configuration information or parameter values to the terminal device or the network device through a message or signaling, so that the terminal device or the network device determines the communication parameters or the transmission resource according to the values or information. Pre-configuration is similar to configuration, which can be parameter information or parameter values negotiated in advance by the network device and the terminal device, 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 make any limitation.

[0155] Further, the 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" means one or more, and "multiple" means two or more. "And / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which means that A exists alone, A and B exist together, and B exists 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 means any combination of these items, including any combination of single item 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 performed between devices through a direct interface, for example, between network devices and terminal devices, between network devices and network devices, or within a device, for example, between components in a device, between modules, between chips, between software modules or hardware modules through a bus, a wire or an interface. Sending and receiving can also be indirectly performed between devices through an intermediate device, for example,

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

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

[0161] For example, the area can have at least one of the following properties: shape, contour, size, radius, area, geographical position, etc. In addition, the “area” can also have a height attribute, that is, the area can be understood as a geographical area at a given height or within a height range. For example, the area can refer to a geographical area with an altitude of 0 km or within an altitude range of 0 km ± 2 km, or a geographical area with a certain average altitude, or a geographical area with a certain specific height, for example, a geographical area with an altitude of 10 km or within an altitude range of 10 km ± 3 km.

[0162] Alternatively, the above-mentioned area fixed relative to the earth can also be referred to as “wave position”, “geographical area”, “beam coverage area”, “ground fixed cell”, “ground fixed wave position”, etc. Of course, there can be other names, and the present application does not specifically limit the name of the area fixed relative to the earth.

[0163] In a possible implementation, the shapes, contours, sizes, radii, areas of different regions can or can not be the same. Different regions have different geographical positions. 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 that the contour, size or geographical position of the region does not change with time, for example, 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 that the contour of the region and the points in the region can be described by a fixed coordinate system of the Earth, or the coordinates of each point on the contour of the region in the fixed coordinate system of the Earth are fixed and unchanged.

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

[0167] In a possible implementation, the surface of the Earth 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 method of the regions (e.g., whether to start numbering from 1 or from 0) and the correspondence between the regions and the indexes. Alternatively, a protocol can define the numbering method of the regions and the correspondence between the regions and the indexes. Based on the index of a region, the geographical position of the region and other information can be determined.

[0168] Optionally, the multiple divided regions can completely cover the surface of the Earth, for example, any position on the surface of the Earth belongs to a region; alternatively, the multiple divided regions can cover part of the geographical positions on the Earth, for example, the multiple regions can not cover the South Pole and / or the North Pole of the Earth, that is, the South Pole and / or the North Pole can not have the regions.

[0169] Optionally, the manner of dividing the multiple regions can be defined by a protocol or can be defined by a network device. The dividing manners defined by different network devices can or can not be the same. A same network device can also define multiple dividing manners.

[0170] As a first possible partitioning manner, the earth surface can be partitioned using a grid of latitude and longitude with a granularity, for example, the earth surface can be partitioned using a grid of latitude and longitude with a granularity of 1 degree. If only this discretization is used, the whole world can be partitioned into 360x360=129600 regions, and the terminal device and the network device can agree on the indices of the 129600 regions as 0, 1, …, 129599, or can also agree on the indices as 1, 2, …, 129600.

[0171] Optionally, when the height attribute of the geographical region is introduced, multiple grids partitioning the earth surface can be defined, for example, the grid with an altitude of 0 km or within a range of 0 km plus or minus 2 km can be partitioned using a grid of latitude and longitude with a granularity of 1 degree, resulting in 129600 regions. The grid with an altitude of 10 km or within a range of 10 km plus or minus 3 km can also be partitioned using a grid of latitude and longitude with a granularity of 1 degree, resulting in 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 grid index of the 0 km altitude, and the last 129600 serial numbers represent the grid index of the 10 km altitude.

[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 partitioning manner, the earth surface can be partitioned using multiple grids of latitude and longitude with different granularities, for example, a grid of latitude and longitude with a granularity of 1 degree is used to partition a part of the earth surface or a part of the administrative region, and a grid of latitude and longitude with a granularity of 2 degrees is used to partition another part of the earth surface or administrative region.

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

[0175] As a third possible partitioning manner, the earth surface can be partitioned using administrative regions. For example, a township-level administrative region is taken as a region.

[0176] As a fourth possible partitioning manner, for a GEO satellite, the 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 fixed relative to the earth.

[0177] In actual application, the earth surface can be divided in combination with multiple division manners, for example, the earth surface or part of administrative regions is divided into a longitude and latitude grid with a granularity of 1, and another part of the earth surface or administrative regions is divided according to administrative regions.

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

[0179] (7) In the embodiments of the present application, "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, and the other part of the to-be-indicated information is known or agreed in advance. For example, the arrangement order of each information agreed in advance (for example, predefined by a protocol) can be used to indicate a specific information, 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 among various embodiments can be mutually referred to, unless otherwise specified. In the various embodiments in 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 embodiments described below do not constitute a limitation on the protection scope of the present application.

[0181] Reference is made to Figure 1 a schematic diagram of an architecture of a communication system 1000 to which embodiments of the present application are applied. As shown in Figure 1 , the communication system includes a radio access network (RAN) 100 and a core network 200. Optionally, the communication system 1000 can also include an Internet 300. The RAN 100 includes at least one RAN node (e.g., 110a and 110b in Figure 1 , collectively referred to as 110) and at least one terminal (e.g., 120a-120j in Figure 1 , collectively referred to as 120). The RAN 100 can also include other RAN nodes, such as wireless relay devices and / or wireless backhaul devices (not shown in Figure 1 ). The terminals 120 are connected to the RAN nodes 110 wirelessly, and the RAN nodes 110 are connected to the core network 200 wirelessly or wiredly. 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. Terminals and terminals, and RAN nodes and RAN nodes can be connected to each other through wired or wireless means.

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

[0183] Satellite communication has wider coverage than traditional mobile communication systems, and the communication cost is independent of the transmission distance, which can overcome natural geographical obstacles such as oceans, deserts, and mountains. 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] GEO satellites are also known as geostationary orbit satellites, 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 disadvantages of GEO satellites are also relatively prominent: 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. MEO satellites have 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 LEO satellites, and they are mainly used for positioning and navigation. In addition, the orbital height of 300-2,000 km is called low-orbit (LEO), and LEO satellites have a lower orbital height than MEO and GEO satellites, smaller data propagation delay, lower power loss, and relatively lower launch cost. Therefore, LEO satellite communication networks have made great progress in recent years and have attracted attention.

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

[0186] The following will illustrate the two modes through the implementation modes shown in Figure 2a , Figure 2b , Figure 2c and Figure 2d .

[0187] As shown in the implementation mode of the transparent mode in Figure 2a , the satellite and the gateway (i.e., the NTN Gateway in Figure 2a ) act as a relay, that is,Figure 2a The Remote Radio Unit shown is used as a relay for communication between the terminal equipment and the gNB. In other words, in transparent transmission mode, the satellite has a relay function.

[0188] For example, in Figure 2b In the implementation of the transparent transmission mode shown, when the satellite (including GEO, MEO, LEO, etc.) operates in transparent transmission mode, the satellite has a relay forwarding function. The gateway station (or signaling station) has the function of a base station or part of the function of a base station; in this case, the gateway station can be regarded as a base station. Alternatively, the base station and the gateway station can be deployed separately, in which case the delay of the feeder link includes two parts: the delay from the satellite to the gateway station and the delay from the gateway station to the gNB.

[0189] Optionally, the transparent transmission mode can be used as an example where the gateway station and gNB are together or in close proximity. For cases where the gateway station and gNB are far apart, the feeder link delay can be calculated by adding the delay from the satellite to the gateway station and the delay from the gateway station to the gNB.

[0190] like Figure 2c In the implementation of the regeneration mode shown, the satellite and the gateway station (i.e. Figure 2c The NTN Gateway (gNB) in the satellite acts as a gNB, enabling communication with terminal devices. In other words, in regeneration mode, the satellite functions as a base station or partially as such, and can be considered a base station in this case.

[0191] For example, in Figure 2d In the implementation of the regeneration mode shown, when satellites (including GEO satellites, MEO satellites, LEO satellites, etc.) operate in regeneration mode, compared to... Figure 2b In the implementation shown, the satellite has the function of a base station or part of the function of a base station. In this case, the satellite can be regarded as a base station (i.e., an airborne base station).

[0192] Optionally, in Figure 2b and / or Figure 2d In this case, satellites can be used in other ways, such as drones or high-altitude platforms as shown in the image.

[0193] It should be noted that NTN and terrestrial network base stations can be interconnected through a common core network. NTN and terrestrial base stations can also access different core networks and interconnect through interfaces between the core networks.

[0194] Furthermore, network devices can determine relevant information about the satellite's orbit based on this ephemeris information. As one implementation example, the ephemeris information may include one or more of the information in Table 2 below.

[0195] Table 2

[0196]

[0197] It should be noted that, in practical applications, the last parameter in Table 2, the time of near-Earth (t), can be used instead. p The same effect can be achieved by replacing the representation with true anterior angle or level anterior angle, as shown in Table 3.

[0198] Table 3

[0199]

[0200] In one possible implementation, the satellite can operate in an earth-fixed system, or a quasi-earth-fixed system or a satellite-fixed system. The earth-fixed mode or quasi-earth-fixed system can also be called a staring system, and the satellite-fixed system can also be called a non-staring system.

[0201] As an implementation example, in Figure 2e In the non-gazing system shown, within a continuous time period (times T1, T2, and T3 belong to this continuous time period), the satellite beam coverage area moves along with the satellite; Figure 2e In the staring system shown, during a continuous period of time (times T1, T2, and T3 belong to this continuous time period), the satellite dynamically adjusts the beam direction so that the beam approximately covers the same area of ​​the ground.

[0202] The following will be through Figures 3a to 3c An exemplary description of the implementation of the gaze system is provided.

[0203] In a staring system, a geographic area is covered by one or more satellite beams during any predetermined time period. A satellite cell can be the signal coverage area of ​​a single satellite beam or it can consist of signal coverage areas of multiple satellite beams; that is, a ground cell can be a fixed ground cell. During any predetermined time period, the terminal device camps on the satellite beam corresponding to its location. In the next time period, as the satellite moves, the satellite beam covering a geographic area may change; that is, the satellite beam covering the geographic area will change from the source satellite beam to the target satellite beam. The source satellite beam and the target satellite beam can belong to the same satellite or different satellites.

[0204] As an example, in a staring system, the signal coverage area of ​​the same satellite beam varies at different times. For example... Figure 3aAs shown, the satellite beam covers geographic region 1 in time period 1 and geographic region 2 in time period 2. Time period 1 and time period 2 can be consecutive time periods of the same length. Geographic region 1 and geographic region 2 may or may not overlap. The figure shows an example where these two geographic regions do not overlap.

[0205] In addition, from the perspective of ground coverage, there are two situations.

[0206] Scenario 1: Satellite coverage on the ground is fixed.

[0207] For example, fixed cells can be divided on the ground, and each ground cell can be covered by different satellite beams at different times. In other words, the range of each ground cell can be one or more geographical areas covered by the signal coverage of the satellite beam.

[0208] like Figure 3b As shown, for a certain geographical area (i.e., a ground cell), during time period 1 (i.e., the time period from start time t1 to end time t2), the ground cell is covered by satellite beam 2, meaning that the signal of the ground cell is transmitted through satellite beam 2; during time period 2 (i.e., the time period from start time t2 to end time t3), the ground cell is covered by satellite beam 1, meaning that the signal of the ground cell is transmitted through satellite beam 1.

[0209] Optional, in Figure 3b In the implementation shown, the coverage areas of satellite beam 1 and satellite beam 2 overlap in two adjacent time periods, meaning they can both completely cover the same geographical area. Here, t2-t1=t3-t2=△t, where △t is the duration for which a satellite beam covers a ground cell, such as 15 seconds.

[0210] Optionally, in the above scenario one, the beam covering the ground cell can be transmitted via a satellite beam, that is, the coverage of a satellite beam matches the size of the ground cell; in other embodiments, the signal covering the ground fixed cell can also be transmitted via a satellite, that is, the coverage range of a ground fixed cell matches that of a satellite. In this case, the ground fixed cell can be covered by multiple beams.

[0211] Scenario 2: Satellite coverage on the ground is not fixed.

[0212] For example, in scenario two, although it is also a staring beam, it may be impossible to divide the ground fixed cells because after the satellite moves, the coverage of the next beam in the next time period cannot exactly match the coverage of the previous beam.

[0213] like Figure 3cAs shown, one geographical area is covered by beam 1 in time period 1 (i.e., a time period with a start time t1 and an end time t2), and is covered by beam 2, beam 3 and beam 4 in time period 2 (i.e., a time period with a start time t2 and an end time t3). That is, in time period 2, there is no satellite beam that just covers the area covered by the last beam in the last time period.

[0214] 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-terrestrial communication system such as a satellite communication system, a high-altitude communication platform, etc. 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, or to a terminal device in RRC_INACTIVE or RRC_IDLE.

[0215] Optionally, the NR system can also have other names, such as 5G, 5G NR, etc.

[0216] As shown in Figure 4 , an example of a 5G regenerated satellite communication system architecture is shown. The ground terminal device accesses the 5G new air interface network through the 5G base station deployed on the satellite, and is connected to the ground core network through the feeder link. At the same time, there can be an inter-satellite link between the satellites to complete the signaling interaction and user data transmission between base stations and base stations. Figure 4 The description of the devices and interfaces in

[0217] 5G core network: user access control, mobility management, session management, user security authentication, billing and other services. It is composed of multiple functional units and can be divided into control plane and data plane functional entities. Access and mobility management unit (AMF) is responsible for user access management, security authentication, and mobility management. User plane unit (UPF) is responsible for managing user plane data transmission, traffic statistics and other functions. Session management function (SMF) is mainly used for session management in mobile networks, such as session establishment, modification, and release.

[0218] Ground station: responsible for forwarding signaling and service data between satellite base station and 5G core network.

[0219] 5G new radio: wireless link between terminal and base station.

[0220] Xn interface: interface between 5G base stations, mainly used for signaling interaction such as handover.

[0221] NG interface: interface between 5G base station and 5G core network, mainly interacting with non-access stratum (NAS) signaling of core network and user service data.

[0222] In addition, the network devices in the ground network communication system and the satellites in the NTN communication system can be regarded as network devices. The device for implementing the function of the network device can be a network device; it can also be 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. When describing the technical solutions provided by the embodiments of the present application, the device for implementing the function of the network device is deployed in the satellite as an example to describe the technical solutions provided by the embodiments of the present application. It can be understood that when the method provided by the embodiments of the present application is applied to the ground network communication system, the actions performed by the satellite can be applied to the base station or the network device to perform.

[0223] In the embodiments of the present application, the device for implementing the function of the terminal device can be a terminal device; it can also be a device capable of supporting the terminal device to implement the function, such as a chip system, which can be installed in the terminal device. In the embodiments of the present application, the chip system can be composed of a chip, or can include a chip and other discrete devices. In the technical solutions provided by the embodiments of the present application, the device for implementing the function of the terminal device is taken as an example to describe the technical solutions provided by the embodiments of the present application.

[0224] In addition, the satellite described above can be a stationary satellite, a non-stationary satellite, an artificial satellite, a low-orbit satellite, a medium-orbit satellite, and a high-orbit satellite, and the like, which are not specifically limited herein.

[0225] The above describes various scenarios of wireless communication involved in the present application. It should be understood that the above is only an exemplary description of the scenarios in which the present application can be applied, and the present application can also be applied to other application scenarios, which are not limited herein. The wireless communication process involved in the present application will be described below.

[0226] In the wireless communication process, mobility management is an important feature, which can be used to manage the movement and / or handover of a terminal device (such as a UE) between different network nodes. Generally, mobility management includes cell handover and cell reselection, which will be described below through some examples.

[0227] ① Cell handover process.

[0228] Generally, the handover procedure of the ground network mainly includes the following steps:

[0229] 1. Cell handover measurement: the network device (for example, the base station) usually issues a plurality of measurement configurations corresponding to cells (including a serving cell and a neighbor cell) to the terminal device (for example, the UE), and the UE measures the cell signal quality (such as received signal strength indication (RSSI), reference signal received power (RSRP), and reference signal received quality (RSRQ)) according to the measurement configuration;

[0230] 2. Measurement result reporting: the UE reports the measurement result to the base station, and the reporting mode can be periodic reporting or event-triggered reporting. In the event-triggered reporting, the reporting condition is usually configured as the serving cell signal quality being less than a threshold 1 and / or the neighbor cell signal quality being greater than a threshold 2;

[0231] 3. Handover decision: the base station selects a suitable target cell according to the reported result, 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, and the like;

[0232] 4. Handover execution: the UE receives the control information related to handover from the serving cell, and completes the access procedure in the target cell. The process of handover execution can include the RACH procedure.

[0233] It can be understood that the UE can send a RACH request message in the process of performing handover; wherein, the RACH procedure includes the interaction process of the RACH request message.

[0234] For example, the RACH request message can be message 1 (MSG 1) or message A (MSG A).

[0235] Optionally, the cell handover procedure can be applicable to a terminal device in RRC_CONNECTED.

[0236] ② Cell reselection procedure. After cell reselection, the terminal resides in a new cell.

[0237] Generally, the network device (for example, the network device is a base station) usually sends the parameters related to the adjacent cell to the terminal device (for example, the terminal device is a UE) in the form of broadcast, and the UE measures the signal of the adjacent cell according to the parameters of the adjacent cell, and compares the measurement value (such as RSRP and / or RSRQ, etc.) and the configured (or pre-configured) parameters (such as reselection threshold, etc.), and autonomously reselects to the target cell when the conditions are met.

[0238] Optionally, the cell reselection procedure can be applicable to a terminal device in RRC_IDLE or RRC_INACTIVE.

[0239] After the terminal device selects the target cell, if the terminal device does not need to send signaling (such as mobility registration procedure) or data, the terminal device resides in the target cell. Residing in the target cell means that the terminal device maintains downlink synchronization with the target cell, reads the broadcast information of the target cell, and listens to the paging message, etc.

[0240] In the communication system shown in the foregoing Figure 1 / Figure 2a / Figure 2b / Figure 2c / Figure 2d / Figure 2e / Figure 4 In the communication system shown in the foregoing

[0241] Unlike the ground base station to which the TN cell belongs, the satellite base station to which the NTN cell belongs can have a high-speed movement, which leads to the possibility that the satellite beam serving the terminal device located on the ground can change frequently. The changed satellite beam can be referred to as a target satellite beam.

[0242] 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 a connected state under the coverage of the beam, 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 a terminal device in an idle state, after the beam in which the terminal device resides 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).

[0243] However, each terminal device needs to determine the target satellite beam corresponding to the terminal device through an independent signaling transmission process, which will lead to a sharp increase in signaling overhead, and further lead to an increase in power consumption of the terminal device.

[0244] 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.

[0245] Please refer to Figure 5 An implementation example of the communication method provided by the present application is shown in the figure, and the method includes the following steps.

[0246] It should be understood that in the following, the different communication devices are taken as the execution subject of the interaction example to illustrate the method, but the present application does not limit the execution subject of the interaction example. 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.

[0247] 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.

[0248] 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.

[0249] As an example, the third communication apparatus below can be a target network device or a target satellite network device (hereinafter described as a target satellite network device), or the first communication apparatus can be a part of component in the target satellite network device.

[0250] As an example, the fourth communication apparatus below can correspond to a core network device, or the first communication apparatus can be a part of component in the core network device.

[0251] Optionally, in the following scheme, the access network device (e.g., a source satellite network device, a target satellite network device, etc.) can be an ORAN network element.

[0252] S501. The second communication apparatus sends first information, and correspondingly, the first communication apparatus 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 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.

[0253] S502. The first communication apparatus 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 included in the N satellite beams.

[0254] 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 as an example for illustration herein. Optionally, 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,

[0255] It should be understood that the signal coverage area of a 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 a satellite beam can include one or more geographic areas, and a terminal device located in the one or more geographic areas can communicate through the satellite beam.

[0256] Optionally, 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.

[0257] It should be understood that the K time periods are continuous time periods with the same time length, which can be understood as that the K time periods are connected at both ends and each time period has the same time length, or the ending moment of the k th (k is an integer from 1 to K-1) time period of the K time periods is the starting moment of the k+1 th time period of the K time periods, the starting moment of the k th time period is the ending moment of the k-1 th time period of the K time periods, or the 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 the starting 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, a minute, or the like.

[0258] In a possible implementation, the first information received by the first communication apparatus in step S501 can indicate information of the N satellite beams, where the information of any satellite beam includes 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.

[0259] 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 the following: 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.

[0260] 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 starting frequency point and / or an ending frequency point of the communication frequency, or the communication frequency information of the satellite beam can include an index corresponding to the communication frequency.

[0261] 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 the following: a cell identifier (cell ID) of the cell, a physical cell identifier (PCI), or other information.

[0262] 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.

[0263] For another example, the service time information of the satellite beam can indicate one or more of the following: a starting time information (e.g., a starting time point or a starting time unit), a duration, and a termination time information (e.g., a termination time point or a termination time unit) of the service of the satellite beam. For an example, the service time of the satellite beam refers to the time when the satellite beam serves the geographic area included in the information of the satellite beam.

[0264] Optionally, the first information received by the first communication device 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 the transmission overhead of the information of the satellite beam can be reduced.

[0265] 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 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. 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 corresponding to the one or more satellite network devices. 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 movement speed of each satellite in the constellation at any time can be determined. For an 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 following: a frequency used by a satellite beam of a satellite in the constellation, a staring time point and a staring time period information (i.e., a time length for serving a geographic area) of the satellite beam, and a physical cell identifier corresponding to the satellite beam.

[0266] It should be noted that the frequency used by the satellite beam can be related to the geographic area served by the satellite beam, for example, different frequencies are used when the same satellite beam of the same satellite serves different geographic areas. The frequency used by the satellite beam can also be independent of the geographic area served by the satellite beam, i.e., the same frequency is used by the satellite beam when serving any geographic area. The staring time point and the staring time period of the satellite beam can be configured to be the same for the entire constellation, i.e., the staring time point and the staring time period 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 point and the staring time period of the satellite beam can also be configured for each satellite, i.e., the staring time point and the staring time period of the satellite beams of different satellites can be different.

[0267] 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).

[0268] 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.

[0269] Based on Figure 5In the illustrated scheme, the first information received by the first communication device in step S501 is used to indicate information of N satellite beams, and thereafter, in step S502, 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. 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 device 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 a 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 a 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.

[0270] 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 a target satellite beam, which can greatly reduce the signaling overhead and improve the communication efficiency.

[0271] In the above scheme, Figure 5 In a possible implementation of the method, in each time period of the K time periods, at least one satellite beam of the N satellite beams has a signal coverage area including a 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 a target satellite beam according to information of at least one satellite beam of the N satellite beams whose coverage area includes the second geographic region at any time period of the K time periods. In this way, after the first terminal device moves from the first geographic region to the second geographic region, the first terminal device can still determine a target satellite beam using the first information, maintaining the continuity of the communication. Compared with the terminal device blindly searching for the satellite and the satellite beam without the first information at 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 device, and improving the communication efficiency.

[0272] 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.

[0273] In the above scheme, Figure 5In a possible implementation of the method, in step S502, the process that 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; and any one of the M satellite beams has a signal coverage area containing the geographic area where the first terminal device currently locates, the geographic area where the first terminal device currently locates being contained in the first geographic area or the second geographic area, and M is less than or equal to N.

[0274] 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, any one of the M satellite beams has a signal coverage area containing 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 realize fast determination of the target satellite beam while avoiding the situation that a communication failure occurs due to determination of a satellite beam whose signal coverage area does not contain the geographic area where the first terminal device currently locates as the target satellite beam.

[0275] Optionally, in a case where the first terminal device moves in or remains stationary in the first geographic area, the geographic area where the first terminal device currently locates is contained in the first geographic area.

[0276] Optionally, in a case where the first terminal device moves from the first geographic area to the second geographic area, the geographic area where the first terminal device currently locates is contained in the second geographic area.

[0277] As an example, in the N satellite beams, the M satellite beams serve the geographic area where the first terminal device currently locates for a time duration greater than or equal to that of the other N-M satellite beams. In other words, in the N satellite beams, the M satellite beams serving as candidate beams serve the geographic area where the first terminal device currently locates for a longer time duration, and in this way, the first communication device can select the M satellite beams serving for a longer time duration as candidate beams, and can select a satellite beam serving for a longer time duration as the target communication beam as much as possible, which can reduce the frequency of re-determination of the target satellite beam (for example, beam switching / beam reselection), and further reduce the communication overhead.

[0278] It should be understood that the time length of the satellite beam serving a certain geographical area can be understood as a service time length of the satellite beam serving 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.

[0279] In the above process, after the first communication device determines the candidate M 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 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 candidate M satellite beams as the target satellite beam, so as to improve the communication quality of the subsequent communication of the first communication device based on the target satellite beam.

[0280] Optionally, the measurement result can be used to characterize the signal quality, for example, the measurement result can include one or more of reference signal receiving power (RSRP), reference signal receiving quality (RSRQ), signal and interference plus noise ratio (SINR), or other parameters.

[0281] In Figure 5 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.

[0282] Example A: the first communication device camps on a target satellite cell (or a target satellite network device) corresponding to the target satellite beam.

[0283] 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 obtain synchronization (e.g., downlink synchronization) based on the target satellite beam and then camp on the target satellite cell (or the target satellite network device) corresponding to the target satellite beam. 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.

[0284] 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.

[0285] As an example, as shown in Figure 6 compared to the method shown in Figure 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 Figure 6 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

[0286] In Example B, the first communication device can perform a RACH procedure through the target beam, so that the first terminal device can switch from a source network device to a 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, i.e., without initiating the RACH procedure.

[0287] Optionally, in Example B, the first communication device performing the RACH procedure through the target beam includes: the first communication device sending a RACH request message through the target beam.

[0288] 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 a source cell; accordingly, 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; accordingly, the first communication device can perform the process of Example B described above. Wherein, 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.

[0289] In a possible implementation of the example B, the receiving time or the sending time of the first information in the step S501 is located in a first time period (which can be any one of the K time periods). In addition, in the step F, the first communication device performs the RACH procedure through the target beam includes any one of the following:

[0290] the first communication device performs the RACH procedure through the target beam at the start time (or the start time point) of the next time period of the first time period; or,

[0291] the first communication device performs the RACH procedure through the target beam at the start time (or the start time point) of the next time period of the first time period after a first time length, the number of time units contained in the first time length is determined based on a random number, and the number of time units contained in the first time length is less than or equal to a threshold.

[0292] Specifically, the first communication device can perform the RACH procedure based on any one of the above to improve the flexibility of the implementation scheme. Moreover, in the case where the first communication device performs the RACH procedure based on the first time length, since the number of time units contained 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 situation that different terminal devices perform the RACH procedure at the same time, thereby improving the communication efficiency.

[0293] Correspondingly, the first information can include the threshold, that is, the first communication device obtains the threshold from the second communication device through a broadcast or a groupcast message, or the threshold can also be pre-configured in the first communication device, or the threshold can also be predefined through a standard / protocol.

[0294] In another possible implementation of the example B, as shown in Figure 6 the method further includes: Figure 5

[0295] 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. In addition, in the step F, the first communication device performs the RACH procedure through the target beam includes any one of the following:

[0296] the first communication device performs the RACH procedure through the target beam immediately after receiving the second information in the step A; or,

[0297] ​After receiving the second information in step A, the first communication device delays for a second duration before executing the RACH procedure through the target beam. The number of time units included in the second duration is determined based on random numbers, and the number of time units included in the second duration is less than or equal to a threshold. Accordingly, the second information may include the threshold, or the threshold may be pre-configured in the first communication device, or the threshold may be predefined by a standard / protocol.

[0298] Specifically, the first communication device can execute the RACH procedure based on any of the above-mentioned methods to improve the flexibility of the solution implementation. Furthermore, when the first communication device executes the RACH procedure based on the second duration, since the number of time units included in the second duration is determined based on random numbers, one or more terminal devices located in the same geographical area (e.g., the first geographical area) can execute the RACH procedure based on random numbers within the specified duration. This allows the one or more terminal devices to complete access within the specified duration and also avoids or reduces conflicts caused by different terminal devices executing the RACH procedure at the same time, thereby improving communication efficiency.

[0299] Optionally, the second information can be sent via broadcast or multicast. Accordingly, the second information is used to instruct one or more terminal devices (including the first terminal device) located in the same geographical area (e.g., the first geographical area) to switch the source satellite beam connected to them. In this way, the second information can realize batch switching instructions for one or more terminal devices in the same geographical area to reduce overhead.

[0300] In one possible implementation, the first communication device may also obtain the handover instruction based on other methods. For example, the first information received by the first communication device in step S501 may also be used to indicate switching the source satellite beam to which the first terminal device is connected. In other words, in addition to indicating information for N satellite beams, the first information may also be used to indicate switching the source satellite beam to which the first terminal device is connected, thus reusing the first information to indicate more information and reducing overhead.

[0301] Optionally, the first information is also used to instruct one or more terminal devices (including the first terminal device) located in the same geographical area (e.g., the first geographical area) to switch the source satellite beam connected to them. In this way, the first information can enable batch switching instructions for one or more terminal devices in the same geographical area to reduce overhead.

[0302] In one possible implementation, the satellite network equipment corresponding to the source satellite beam of the first terminal device is used as an example, such as the second communication device. Figure 6 As shown, Figure 5 The method shown also includes:

[0303] 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.

[0304] 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.

[0305] 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.

[0306] 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.

[0307] 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.

[0308] 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.

[0309] 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.

[0310] 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.

[0311] 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.

[0312] 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.

[0313] As shown in FIG. 6, the foregoing method further includes: Figure 6

[0314] 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.

[0315] 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.

[0316] As shown in FIG. 6, the foregoing method further includes: Figure 6

[0317] 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.

[0318] Step E. The fourth communication device sends the fourth information, and correspondingly, the third communication device receives the fourth information.

[0319] 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.

[0320] 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 further 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.

[0321] ​​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.

[0322] 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.

[0323] 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.

[0324] 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.

[0325] 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.

[0326] 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.

[0327] 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.

[0328] 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.

[0329] 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.

[0330] 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.

[0331] In order to facilitate the understanding of the foregoing Figure 5 and Figure 6 The following will be described in combination with more examples.

[0332] Please refer to Figure 7a Another schematic diagram of the communication method provided by the present application. In order to facilitate the following reference, Figure 7a The method shown in is recorded as Example One. In the example shown in Figure 7a In the example shown in, 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 a network device, which are a candidate satellite beam corresponding network device_1 (i.e., a network device corresponding to a beam 2) and a candidate satellite beam corresponding network device_2 (i.e., a network device corresponding to a beam 3)), one of which is the third communication device, and the first network element and the source satellite network device are different devices.

[0333] Step 1. The first network element sends first information to the source satellite network device. The description of the first information can be referred to FIG. S501.

[0334] The first information can also indicate the 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 geographic area corresponding to the first information overlaps with the coverage area of the beam 1 of the source satellite network device.

[0335] 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 in the K time periods, and the first information indicates the information (or auxiliary information) of N satellite beams, wherein the N satellite beams include at least one of the following:

[0336] information of a satellite beam covering a second geographical area, the second geographical area being a geographical area adjacent to the first geographical area, at a current time period;

[0337] a satellite beam covering the first geographical area at K-1 time periods after the current time period; or,

[0338] a satellite beam covering the second geographical area at K-1 time periods after the current time period.

[0339] wherein the information of any one of the N satellite beams comprises at least one of:

[0340] 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 (note that the 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 geographical area (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 comprises a satellite identifier and a satellite ephemeris, wherein the satellite ephemeris can include time, position coordinates of the satellite, and a moving speed of the satellite.

[0341] Step 2. The source satellite network device (i.e., the network device corresponding to the beam 1) sends the first information to the UE within its coverage. After receiving the first information in step 1, the source satellite network device sends the first information to the UE through the beam 1 corresponding to the first information.

[0342] It should be noted that step 2 is an example of the foregoing step S501, and the implementation processes of the two steps can be mutually referred.

[0343] Optionally, the source satellite network device (i.e., the network device corresponding to the beam 1) can send the first information to the UE in a broadcast manner, or in a multicast manner. For example, when the area served by the satellite beam is a ground fixed area (such as the scenario shown in FIG. 8A), the satellite beam can send the first information to the UE in a broadcast manner; when the geographical area served by the satellite beam is not fixed (such as the scenario shown in FIG. 8B), the satellite beam can send the first information to the UE in a multicast manner, Figure 3b Figure 3c

[0344] For example, as shown in FIG. 8A, when the area served by the satellite beam is a ground fixed area, the satellite beam can send the first information to the UE in a broadcast manner; as shown in FIG. 8B, when the geographical area served by the satellite beam is not fixed, the satellite beam can send the first information to the UE in a multicast manner, Figure 3c ​​In the illustrated scenario, in the next time period, the satellite beams covering the area covered by beam 1 (beam 1 in the figure) include beam 2, beam 3 and beam 4, accordingly, beam 1 can divide the UEs 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 a multicast manner, the first information received by the UE group in the area served 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 served 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 served 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 to send to different UE groups according to the first information. In order to reduce complexity, the first information can also be sent to all UEs in the coverage range of beam 1 in a broadcast manner in this scenario, and the target satellite beam is determined by the UE according to the beam coverage information in the first information.

[0345] It should be noted that even for the scenario of satellite covering a fixed ground (such as Figure 3b the illustrated scenario), in the next time period, the satellite covering the geographic area can also include one or more, that is, 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.

[0346] 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, for example, establish a non-access stratum (NAS) connection or establish an internet protocol (IP) connection, so that the first network element sends the first information to the UE. This scenario is not presented in Figure 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 UE in more time periods than the current time period and the next time period, which can reduce the frequency of the first network element sending the first information to the terminal and reduce the air interface overhead.

[0347] Step 3. The UE determines the time when beam 1 ends the service and the candidate satellite beam serving the location of the UE in the next time period according to the first information.

[0348] For example, the candidate satellite beam can be M satellite beams in N satellite beams, taking M=2 as an example, the M satellite beams can include Figure 7a beam 2 and beam 3 in the figure, beam 2 corresponds to network device_1 corresponding to the candidate satellite beam, and beam 3 corresponds to network device_2 corresponding to the candidate satellite beam.

[0349] 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 Figure 3b Figure 3c It is assumed here that the location of the UE is covered by two satellite beams in the next time period, i.e., beam 2 and beam 3.

[0350] Step 4a. The UE synchronizes with beam 2 and performs signal quality measurement to obtain a measurement result.

[0351] Step 4b. The UE synchronizes with beam 3 and performs signal quality measurement to obtain a measurement result.

[0352] 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.

[0353] 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 satellite can be aligned to obtain a stronger downlink signal.

[0354] As an example, the information of the satellite beam indicated by the first information includes the identity of the satellite cell, 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.

[0355] Step 5. The UE selects a target satellite beam and camps on the target satellite beam.

[0356] 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.

[0357] 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 the 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.

[0358] ​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 service 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 service time, and then select the target satellite beam according to the priority coefficient.

[0359] Step 6. The terminal camps on the target satellite beam (for example, beam 2).

[0360] Among them, 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.

[0361] Please refer to Figure 7b Another schematic diagram of the communication method provided for the application. In order to facilitate the reference hereinafter, Figure 7b The method shown is referred to as embodiment two. In Figure 7b In the example shown, the first communication device is a UE, the second communication device and the third communication device are located in the same network device (that is, 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.

[0362] 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. The flow 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).

[0363] 1. Refer to step 1 of embodiment one.

[0364] 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.

[0365] 3. The UE and the satellite network device wait for the next time period according to the first information.

[0366] 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).

[0367] 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.

[0368] 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.

[0369] 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.

[0370] 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 location of the UE in the next time period.

[0371] Step 5. The UE measures the candidate satellite beam and determines the target satellite beam.

[0372] 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.

[0373] 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.

[0374] 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 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.

[0375] 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.

[0376] Step 6. Satellite network equipment begins to cache downlink packets.

[0377] For example, after the satellite network device sends a handover instruction, or when the next time period is about to arrive or arrives, the satellite network device begins to cache downlink packets.

[0378] Optionally, the satellite network equipment can continue to send cached messages through beam 1, which can reduce handover latency.

[0379] Optional, in Figure 7b In the scenario shown, since the target satellite beam and the source satellite beam belong to the same satellite network device, there is no need to forward data packets.

[0380] Step 7. Synchronize the UE with the target satellite beam.

[0381] For example, the UE can disconnect the source beam and perform uplink synchronization with the target satellite beam.

[0382] For example, a UE can initiate a RACH procedure for uplink synchronization. Optionally, to avoid process conflicts caused by multiple UEs simultaneously initiating RACH procedures within the source beam coverage area, a UE can wait for a random duration less than the maximum waiting time before initiating the RACH procedure. This maximum waiting time can be set through pre-configuration or configuration, for example, by including an indication of the maximum waiting time in the handover indication message / signaling / information in step 4 or in the first information in step 2.

[0383] Step 8. The satellite network equipment begins sending cached data to the UE via the target beam.

[0384] Optionally, after the UE synchronizes with the target beam, the satellite network device can send the data cached in step 6 to the UE.

[0385] Step 9. The terminal and satellite network equipment transmit and receive data via the target beam.

[0386] Please see Figure 7c This is another schematic diagram illustrating the communication method provided in this application. For ease of later reference, Figure 7c The method shown is referred to as Example 3. Figure 7c In the example shown, the first communication device is the UE, the second communication device is satellite network device 1 (i.e., the network device corresponding to the source beam or the source satellite network device), and the third communication device is satellite network device 2 (i.e., the network device corresponding to the target beam or the target satellite network device). The first network element and the source satellite network device are different devices, and the core network equipment includes the second and third network elements. The second network element can be a core network control plane network element, and the third network element can be a core network user plane network element.

[0387] It should be understood that Embodiment 3 addresses cross-beam handover of the UE caused by the movement of satellite network equipment, and the target beam and the source beam belong to different satellite network equipment. Furthermore, in Embodiment 3, the source satellite network equipment and the target satellite network equipment may not have a direct communication interface; their control plane messages can be forwarded through a second network element, and their user plane messages (such as cached data) can be forwarded through a third network element.

[0388] Step 1. Same as Step 1 in Example 2.

[0389] Step 2. Same as Step 2 in Example 2.

[0390] Step 3. Same as step 3 in Example 2.

[0391] Step 4. Same as step 4 in Example 2.

[0392] Step 5. Satellite network device 1 sends the UE context to the second network element.

[0393] It should be noted that step 5 is an example of an implementation of step D mentioned above, and the implementation processes of these steps can be referenced from each other.

[0394] In this configuration, satellite network device 1 can determine candidate target beams for each UE and send the UE's context and the corresponding satellite identifier of the candidate target beam to a second network element, so that the second network element can send the UE's context to the candidate target satellite. Optionally, the message may also include information about the candidate target beam corresponding to the UE, such as the identifier of the candidate target beam.

[0395] As an example, the UE context sent by satellite network device 1 in step 5 may include the context of a batch of UEs (or all UEs) covered by the source beam.

[0396] by Figure 3b Taking the scenario shown as an example, UEs under one beam may correspond to the same candidate target beam. In this case, satellite network device 1 sends the context of all UEs under that beam to the candidate target satellite corresponding to the candidate target beam. When sending messages, since there may be no transmission link between satellite network device 1 and the candidate target satellite (e.g., satellite network device 2), satellite network device 1 can first send the context of all UEs under the source beam, along with the identification information of the candidate target satellites and the identification information of the candidate target beams corresponding to these UEs, to the second network element. The second network element then sends the UE uplink messages to the candidate target satellites.

[0397] by Figure 3cAs an example of the scenario shown, the UEs under the coverage of a 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. When sending the messages, the satellite network device 1 can send the contexts of the UEs corresponding to the same candidate target beam to the candidate target satellite corresponding to the candidate target beam together. 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 the contexts of a group of UEs 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 uplink of the group of UEs to the candidate target satellite corresponding to the group of UEs.

[0398] 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.

[0399] Step 6. The second network element sends the UE context to the satellite corresponding to the target beam.

[0400] 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.

[0401] 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 identification of the candidate target satellite in step 5.

[0402] 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.

[0403] 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 establish a forwarding tunnel to the third network element, the third network element responds to the message, and sends the allocated tunnel information to the second network element.

[0404] 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.

[0405] Step 7. The second network element receives the response message of the candidate target satellite.

[0406] Optionally, if a forwarding tunnel needs to be established, the response message can include tunnel information of the candidate target satellite.

[0407] Step 8. The second network element informs the third network element to establish a tunnel.

[0408] 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 and sent to the candidate target 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 (corresponding to the address of the candidate target satellite) of the data packet, and forward the data packet to the candidate target satellite (satellite network device 2 in FIG. 1) according to the inner destination address. Figure 7c

[0409] Table 4

[0410]

[0411] In Table 4, GTP-U represents general packet radio system (GPRS) tunneling protocol-user plane (GTP-U).

[0412] 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 to be sent 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.

[0413] Step 9. The second network element sends a response message to the source satellite network device (i.e., satellite network device 1).

[0414] Optionally, if a forwarding tunnel needs to be established, the response message can include tunnel information of the candidate target satellite.

[0415] Step 10. The source satellite network device starts to forward data to the third network element.

[0416] ​Optionally, the source satellite network equipment forwards data to the third network element based on the tunnel established in the previous steps.

[0417] Optionally, there may be multiple candidate target satellites. In this case, multiple forwarding tunnels are established in steps 5-9. The source satellite network device copies the data and forwards the data through the forwarding tunnels corresponding to these multiple candidate target satellites.

[0418] Optionally, in addition to forwarding downlink data to candidate target satellites, the source satellite network device can also continue to send this 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 data.

[0419] Step 11. The third network element sends data to the candidate target satellite network equipment according to the tunnel established in step 9.

[0420] 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 steps 5-9.

[0421] Step 12. The candidate target satellite network equipment caches the received forwarded data.

[0422] Step 13. See Step 5 of Example 2.

[0423] Step 14. See Step 7 of Example 2.

[0424] Step 15. After determining that the terminal has accessed the target satellite beam, the target satellite network equipment sends a user plane path update request to the second network element.

[0425] For example, a user plane path update is used to request a third network element to subsequently send downlink data to the target satellite network device. This message carries downlink tunnel information of the target satellite network device, which is used to receive downlink data from the terminal.

[0426] Optionally, this step is a UE-level message, meaning the message can be targeted at only one UE.

[0427] Step 16. The second network element sends the tunnel information of the target satellite network device to the third network element to update the downlink path.

[0428] 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.

[0429] 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.

[0430] 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.

[0431] Please refer to Figure 7d Another schematic diagram of the communication method provided in the present application is shown. For ease of reference hereinafter, Figure 7d The method shown is referred to as embodiment four. In Figure 7d In the example shown, 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. The second network element can be a core network control plane network element, and the third network element can be a core network user plane network element

[0432] 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 target satellite beam and the source satellite beam belonging to different satellite network devices as an example.

[0433] Step 1. Same as step 1 of embodiment one.

[0434] Step 2. Same as step 2 of embodiment one.

[0435] Step 3. The UE detects that it will soon leave the coverage area of the source beam.

[0436] 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 immediately at the junction time of the two time periods.

[0437] Step 4. The UE determines a candidate target beam and performs measurement on the candidate target beam.

[0438] 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.

[0439] 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.

[0440] 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.

[0441] Step 5. The UE sends a handover request to the source satellite network device, indicating handover to the target beam.

[0442] 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.

[0443] 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.

[0444] Step 6. Handover flow. For example, step 6 can refer to a conventional handover flow (e.g., a cross-base station handover flow).

[0445] 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.

[0446] Please refer to Figure 8 The embodiment of the application provides a communication device 800, which comprises a transceiver unit 802 and a processing unit 801.

[0447] 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.

[0448] 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.

[0449] 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.

[0450] 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.

[0451] 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.

[0452] 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 of the foregoing embodiments of the present application, and will not be described here.

[0453] Please refer to Figure 9 Another schematic structural diagram of a communication apparatus 900 provided in the present application is shown in FIG. 9, which comprises at least an input / output interface 901. The communication apparatus 900 can be a chip or an integrated circuit.

[0454] Optionally, the communication apparatus further comprises a logic circuit 902.

[0455] In the communication apparatus 900, 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; 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 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 contained in the N satellite beams. Figure 8 The transceiver 802 can be a communication interface, which can be an input / output interface 901 in the communication apparatus 900, 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. Figure 9 The transceiver 802 can be a communication interface, which can be an input / output interface 901 in the communication apparatus 900, 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.

[0456] 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; 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 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 contained in the N satellite beams.

[0457] Optionally, the logic circuit 902 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 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 is included in the N satellite beams; and the input and output interface 901 is configured to send the first information.

[0458] 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 a 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.

[0459] 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; wherein 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.

[0460] 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 here.

[0461] In a possible implementation manner, Figure 8 The processing unit 801 shown can be Figure 9 The logic circuit 902 in the processing unit 801.

[0462] Optionally, the logic circuit 902 can be a processing device, and the functions of the processing device can be partially or entirely implemented by software.

[0463] Optionally, the processing device can include a memory and a processor, wherein 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.

[0464] 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.

[0465] 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), microcontroller units (MCU), programmable logic devices (PLD) or other integrated chips, or any combination of the above chips or processors, etc.

[0466] Please refer to Figure 10 The communication device 1000 involved in the above embodiments provided for the embodiments of the present application, which can be specifically the communication device in the above embodiments as a terminal device.

[0467] 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.

[0468] 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.

[0469] In addition, 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. It can implement or execute the various exemplary logical blocks, modules and circuits described in connection with the disclosure. The processor can also be a combination of computing functions, such as a combination of one or more microprocessors, a combination of a digital signal processor and a microprocessor, and the like. Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be described here.

[0470] It should be noted that, Figure 10 The communication device 1000 shown 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, Figure 10 The specific implementation of the communication device can refer to the description in the foregoing method embodiments, which will not be described one by one here.

[0471] Please refer to Figure 11 The above-mentioned communication device structure diagram provided by the embodiments of the present application is related to the communication device in the foregoing embodiments, which can be specifically a network device, and the structure of the communication device can refer to Figure 11 The structure shown.

[0472] The communication device includes at least one processor 1111 and at least one network interface 1114.

[0473] Optionally, the communication device 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, which can include various interfaces, transmission lines or buses in the embodiments of the present application, which are not limited in the embodiments. The antenna 1115 is connected to the transceiver 1113. The network interface 1114 is used for the communication device to communicate with other communication devices through a communication link. For example, the network interface 1114 can include the network interface between the communication device and the core network device, such as the S1 interface, and the network interface can include the network interface between the communication device and other communication devices (such as other network devices or core network devices), such as the X2 or Xn interface.

[0474] The processor 1111 is mainly used for processing communication protocols and communication data, and 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 and a central processor, the baseband processor is mainly used for processing communication protocols and communication data, and the central processor is mainly used for controlling the whole terminal device, executing software programs, and processing data of the software programs. Figure 11 The processor 1111 in the terminal device 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.

[0475] 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.

[0476] Figure 11 Only one memory and one processor are shown. In actual terminal devices, multiple processors and multiple memories can exist. 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, i.e. an on-chip storage element, or an independent storage element, and the embodiments of the present application do not limit this.

[0477] 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, 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 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.

[0478] 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 a receiving unit and a 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.

[0479] It should be noted that, Figure 11 The communication device shown can be specifically configured to implement the steps implemented by the network device in the foregoing method embodiment, and achieve the corresponding technical effects of the network device, Figure 11 The specific implementation of the communication device shown can be referred to the description in the foregoing method embodiments, which will not be repeated here.

[0480] 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.

[0481] 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.

[0482] 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.

[0483] 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.

[0484] 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.

[0485] 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.

[0486] 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.

[0487] The units described as separate components can or can not be physically separated, 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.

[0488] 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.

[0489] 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 in that, include: Receive first information, the first information being used to indicate information about N satellite beams; within each of K time periods, the signal coverage area of ​​at least one of the N satellite beams includes a first geographical region; wherein, the K time periods are consecutive time periods of equal duration, and K and N are positive integers; when receiving the first information, the terminal device located in the first geographical region includes a first terminal device; The target satellite beam for communication with the first terminal device is determined based on the information of the N satellite beams, and the target satellite beam is included in the N satellite beams.

2. The method according to claim 1, characterized in that, Within each of the K time periods, the signal coverage area of ​​at least one of the N satellite beams includes a second geographic region, and the first geographic region is adjacent to the second geographic region.

3. The method according to claim 1 or 2, characterized in that, The step of determining the target satellite beam for communication with the first terminal device based on the information of the N satellite beams includes: Based on the information from the N satellite beams, M satellite beams are determined from the N satellite beams. The M satellite beams are used to determine the target satellite beam. The signal coverage area of ​​any one of the M satellite beams includes the geographical area where the first terminal device is currently located. The geographical area where the first terminal device is currently located is included in the first geographical area or the second geographical area. M is less than or equal to N.

4. The method according to claim 3, characterized in that, The method further includes: Receive at least one signal from some or all of the M satellite beams, and the measurement result of the at least one signal is used to determine the target satellite beam among 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 includes at least one of the following: Information about the 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.

6. The method according to any one of claims 1 to 5, characterized in that, The method further includes: The first terminal device receives a first signal from the target satellite beam, the first signal being used for synchronization; wherein the first terminal device is registered in the target satellite cell or target satellite network equipment corresponding to the target satellite beam; or... The Random Access Channel (RACH) procedure is executed through the target beam.

7. The method according to claim 6, characterized in that, The reception or transmission time of the first information falls within a first time period; the execution of the RACH procedure through the target beam includes any one of the following: The RACH procedure is performed through the target beam at the start of the next time period following the first time period; or, The RACH procedure is performed through the target beam after a first delay from the start time of the next time period after the first time period. The number of time units contained in the first time period is determined based on random numbers, and the number of time units contained in the first time period is less than or equal to a threshold.

8. The method according to claim 6, characterized in that, The method further includes: Receive second information, the second information being used to instruct the switching of the source satellite beam connected to the first terminal device; The RACH procedure performed via the target beam includes any of the following: Upon receiving the second information, immediately execute the RACH procedure through the target beam; or... After receiving the second information, the RACH procedure is executed through the target beam after a second delay. The number of time units contained in the second delay is determined based on random numbers, and the number of time units contained in the second delay is less than or equal to a threshold.

9. The method according to any one of claims 1 to 6, characterized in that, The method further includes: Send a third message, the third message being used to request that the first terminal device be switched from the 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 in that, include: First information is obtained, which indicates information about N satellite beams. Within each of K time periods, the signal coverage area of ​​at least one of the N satellite beams includes a first geographical region. The K time periods are consecutive time periods of equal length, and K and N are positive integers. When receiving the first information, a terminal device located in the first geographical region includes a first terminal device. The information about the N satellite beams is used to determine a target satellite beam for communication with the first terminal device, and the target satellite beam is included in the N satellite beams. Send the first message.

13. The method according to claim 12, characterized in that, The N satellite beams correspond to one or more satellite network devices, and the information of the N satellite beams is determined by the ephemeris information and / or the topology information of the one or more satellite network devices.

14. The method according to claim 12 or 13, characterized in that, The acquisition of the first information includes: Receive the first information.

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

16. The method according to any one of claims 12 to 15, characterized in that, The method further includes: Receive third information, the third information being used to request that the first terminal device be switched from the 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: From the N satellite beams, determine P candidate satellite beams, where P is less than or equal to N; Send 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 geographical region.

18. The method according to claim 17, characterized in that, The method further includes: Receive first tunnel information, which is used to receive data packets from one or more terminal devices located in the first geographical area forwarded by the source satellite network device corresponding to the source satellite beam; Based on the first tunnel information, forward data packets of one or more terminal devices located in the first geographical area, and / or send 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 includes second tunnel information allocated by the source satellite network device. The second tunnel information is used to determine the radio bearer and / or session of the one or more terminal devices corresponding to the received downlink data packets. The radio bearer and / or session is used to transmit the downlink data packets of the one or more terminal devices.

20. A communication method, characterized in that, include: Receive fourth information, the fourth information including context information of one or more terminal devices located in the first geographical region, the one or more terminal devices including the first terminal device; The system 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 the target satellite beam.

21. The method according to claim 20, characterized in that, The method further includes: Send first tunnel information, which is used to receive data packets from one or more terminal devices located in the first geographical area, forwarded by the source satellite network device; Based on the first tunnel information, data packets are received from one or more terminal devices located in the first geographical area.

22. The method according to claim 20 or 21, characterized in that, The data packets forwarded by the source satellite network device from one or more terminal devices located in the first geographical area include data packets from the first terminal device, and the method further includes: After confirming that the first terminal device has successfully executed the RACH procedure, the data packet of the first terminal device is sent to the first terminal device.

23. The method according to claim 22, characterized in that, 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 radio bearer or session of the first terminal device is determined based on the second tunnel information and the packet header forwarded by the source satellite network device. The radio bearer or session is used to transmit the data packets of the first terminal device.

24. A communication method, characterized in that, include: A first message is received from a source satellite network device, the first message including fourth information and an identifier of a target satellite network device, the fourth information including 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 fourth information is sent to the target satellite network device.

25. The method according to claim 24, characterized in that, The method further includes: The system receives fifth information from the target satellite network device, the fifth information indicating the 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 forwarded data from the one or more terminal devices; Based on the tunnel information of the target satellite network device, a tunnel is established between the target satellite network device corresponding to the target satellite beam and the source satellite network device.

26. A communication device, characterized in that, It includes at least one processor; the at least one processor is coupled to at least one memory; the at least one processor is used to perform the method as described in any one of claims 1 to 25.

27. A chip or chip system, characterized in that, It includes at least one processor, said 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 in that, The storage medium stores a computer program or instructions, which, when executed by a communication device, implement the method as described in any one of claims 1 to 25.

29. A computer program product, characterized in that, It includes a computer program or instructions that, when executed by a communication device, implement the method as described in any one of claims 1 to 25.

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