Communication method and apparatus, and terminal, network device and storage medium

Abstract

Disclosed in the present application are a communication method and apparatus, and a terminal, a network device and a storage medium. The method comprises: sending first information to a terminal during the process of executing satellite service link switching without changing a PCI, wherein the terminal is located in an overlapping coverage region between a first satellite and a switched second satellite; and the first information is used for determining an SSB of the second satellite, and at least comprises a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite.

Description

Communication method, device, terminal, network equipment and storage medium

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application with application number 202311002112.6 and application date August 9, 2023, and claims the priority of the above-mentioned Chinese patent application. The entire content of the above-mentioned Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0003] The present application relates to the field of communication technology, and in particular to a communication method, apparatus, terminal, network equipment and storage medium. Background Art

[0004] In the related art, in the scenario where the physical cell identifier (PCI) is not changed, for the soft switching of the satellite service link, there is a situation in which the service coverage of the current satellite and the next satellite overlap for a period of time during the switching process. During this period, the terminal at the same geographical location can observe the two satellites and receive the synchronization signal blocks (SSB) from the two satellites. Since the PCI remains unchanged, the SSBs of the two satellites may be the same, and the terminal may be able to reconnect to the original satellite after measurement.

[0005] Summary of the Invention

[0006] To solve related technical problems, the embodiments of the present application provide a communication method, apparatus, terminal, network equipment and storage medium.

[0007] The technical solution of the embodiment of the present application is implemented as follows:

[0008] An embodiment of the present application provides a communication method, applied to a network device, the method comprising:

[0009] Sending first information to the terminal without changing the PCI and performing the satellite service link switching;

[0010] The terminal is located in an overlapping coverage area of ​​the first satellite and the switched second satellite; the first information is used to determine the SSB of the second satellite, and at least includes a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite.

[0011] The present application also provides a communication method, which is applied to a terminal. The method includes:

[0012] receiving first information sent by a network device while performing satellite service link switching without changing the PCI; wherein the terminal is located in an overlapping coverage area of ​​the first satellite and a second satellite after the switching; and the first information includes at least a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite;

[0013] Based on the first information, the SSB of the second satellite is detected.

[0014] The present application also provides a communication device, including:

[0015] The first sending unit is configured to send first information to the terminal without changing the PCI and performing the satellite service link switching process; wherein,

[0016] The terminal is located in an overlapping coverage area of ​​a first satellite and a second satellite after switching; the first information is used to determine the SSB of the second satellite, and includes at least a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite.

[0017] The present application also provides a communication device, including:

[0018] The first receiving unit is configured to receive first information sent by a network device during a process of performing a satellite service link handover without changing a PCI; wherein the terminal is located in an overlapping coverage area of ​​the first satellite and a second satellite after the handover; and the first information includes at least a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite;

[0019] A detection unit is configured to detect the SSB of the second satellite based on the first information.

[0020] The embodiment of the present application further provides a network device, including a first processor and a first communication interface, wherein:

[0021] The first communication interface is configured to send first information to the terminal without changing the PCI and performing the satellite service link switching process; wherein,

[0022] The terminal is located in an overlapping coverage area of ​​a first satellite and a second satellite after switching; the first information is used to determine the SSB of the second satellite, and includes at least a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite.

[0023] The embodiment of the present application further provides a terminal, including a second processor and a second communication interface, wherein:

[0024] The second communication interface is configured to receive first information sent by a network device during a process of performing a satellite service link handover without changing a PCI; wherein the terminal is located in an overlapping coverage area of ​​the first satellite and a second satellite after the handover; and the first information includes at least a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite;

[0025] The second processor is configured to detect the SSB of the second satellite based on the first information.

[0026] An embodiment of the present application further provides a network device, comprising a first processor and a first memory configured to store a computer program that can be run on the first processor.

[0027] The first processor is configured to execute the steps of any method on the network device side when running the computer program.

[0028] An embodiment of the present application further provides a terminal, comprising a second processor and a second memory configured to store a computer program that can be run on the second processor.

[0029] The second processor is configured to execute the steps of any method on the terminal side when running the computer program.

[0030] An embodiment of the present application also provides a storage medium on which a computer program is stored. When the computer program is executed by a processor, the computer program implements the steps of any method on the network device side, or implements the steps of any method on the terminal side.

[0031] In the communication method, apparatus, terminal, network device, and storage medium provided in embodiments of the present application, while performing a satellite service link handover without changing PCI, the network device sends first information to the terminal; wherein the terminal is located in an overlapping coverage area between a first satellite and a second satellite after the handover; the first information is used to determine the SSB of the second satellite and includes at least a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite; while performing a satellite service link handover without changing PCI, the terminal receives the first information sent by the network device and detects the SSB of the second satellite based on the first information. In the above solution, the network device sends the first information to the terminal to indicate the second SSB index corresponding to the second satellite, enabling the terminal to determine the SSB of the second satellite based on the second SSB index corresponding to the second satellite, thereby accurately detecting the SSB of the second satellite, connecting to the second satellite, and completing downlink synchronization. This not only prevents the terminal from repeatedly accessing the first satellite due to a small RSRP difference between the two satellites, but also avoids introducing Layer 3 handover and modifying the network device configuration, saving additional signaling overhead and reducing power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 is an example diagram of non-terrestrial network communication in the related art without changing the PCI scenario;

[0033] FIG2 is a schematic diagram of a communication method implementation flow in accordance with an embodiment of the present application;

[0034] FIG3 is a schematic diagram of a communication method implementation flow in accordance with an embodiment of the present application;

[0035] FIG4 is a schematic diagram of an interaction flow of a communication method according to an embodiment of the present application;

[0036] FIG5 is a schematic diagram of an interaction flow of a communication method according to an embodiment of the present application;

[0037] FIG6 is a schematic diagram of the structure of a communication device according to an embodiment of the present application;

[0038] FIG7 is a schematic diagram of the structure of a communication device according to an embodiment of the present application;

[0039] FIG8 is a schematic diagram of the network device structure according to an embodiment of the present application;

[0040] FIG9 is a schematic diagram of the terminal structure of an embodiment of the present application. DETAILED DESCRIPTION

[0041] Current non-terrestrial network (NTN) communications support three types of satellite service links based on the motion of the satellite service cell: Earth-fixed, Quasi-Earth-fixed, and Earth-moving. These links differ in whether the service cell moves with the satellite. In the Quasi-Earth-fixed scenario, beams are adjusted so that the same beam maintains coverage of the same geographic area for a limited period of time. During this period, the beam's coverage remains unchanged by satellite movement, while it can cover a different geographic area during another period.

[0042] Taking low-orbit satellites as an example, due to the high-speed movement of satellites, the geographical location of the cell covered by a single satellite changes. For terminals in the same geographical area, if the current satellite cannot provide service, they will switch to the next satellite that can provide service, which is called satellite service link handover. For Quasi-Earth-fixed cells, when a satellite service link handover occurs, because the current satellite and the upcoming satellite are connected to the same base station, an unchanged PCI (unchanged PCI) scenario is proposed. As shown in Figure 1, for the same area covered by two satellites in succession, there is no need to change the PCI. In other words, after connecting to the new satellite, terminals in the same coverage area can reuse most of the high-level protocol stack and high-level / physical layer configurations, thus avoiding additional signaling overhead and power consumption.

[0043] Depending on the satellite deployment, service link switching may occur in the following two situations:

[0044] 1. Hard handover of service link: For terminals in the same geographical area, when the coverage of the current satellite completely disappears, they switch to the next satellite service link. That is, the coverage areas of the two satellites will not overlap at the same time.

[0045] 2. Service link soft handover: During satellite handover, the beams of the two satellite service links will overlap and cover the same area for a period of time. For terminals in the same geographical area, they may observe two satellites and receive synchronization signal blocks (SSBs) from both satellites for a period of time.

[0046] Currently, the system information block (SIB) 19 is configured with satellite auxiliary information related to non-terrestrial network communications, including the relevant configuration of the current serving cell and neighboring cells. The NTN configuration (ntn-Config) includes satellite ephemeris information and other information related to uplink synchronization, such as the common time advance (TA), uplink synchronization validity period, timing relationship offset (K_offset) and other parameters.

[0047] In the unchanged PCI scenario, for a hard handover of a satellite's service link, the moment the current satellite stops serving is different from the moment the next satellite covers the same geographical area. There is a short time interval between the two. The terminal can obtain new satellite ephemeris information and time / frequency domain offset-related information based on the network configuration, thereby synchronizing with the new satellite and performing data transmission.

[0048] For the soft switching of the satellite service link, the service coverage of the current satellite and the next satellite may overlap for a period of time during the switching process. During this period, the terminal at the same geographical location can observe the two satellites and receive SSBs from the two satellites. Since the service cell remains unchanged (PCI remains unchanged), the SSBs of the two satellites may be the same.

[0049] In a soft handover scenario involving a satellite service link, the current terminal cannot distinguish between the SSBs from two satellites. Considering the characteristics of NTN cells, the difference in Reference Signal Received Power (RSRP) or Reference Signal Received Quality (RSRQ) of the service link observed by the terminal at the cell center and cell edge is small. When the coverage of the current satellite service link disappears or changes, the terminal may still measure a strong RSRP or RSRQ. Therefore, during the period when the service areas of two satellites overlap, if the terminal measures similar RSRP or RSRQ strengths for the SSBs from the two satellites, and the satellite service link is selected based solely on the RSRP or RSRQ measurement results, the terminal may reconnect to the original satellite after the measurement.

[0050] In addition, the base station covers the entire cell's service range by sending a single SSB burst. This SSB burst repeats at a certain period. However, the current protocol stipulates that each SSB burst should be sent within 5ms. That is, the base station sends the SSBs of two satellites within 5ms, and the terminal's SSB measurement window lasts for a maximum of 5ms. However, due to the different positions of the two satellites and the extremely long propagation distance, the communication delays between the two satellites and terminals in the same service cell may vary, and the delay difference may be quite large. Therefore, there will be a large time difference between the SSBs of the two satellites tracked by the terminal, making it difficult for the terminal to detect the SSB of the other satellite within 5ms.

[0051] In summary, in the scenario of soft handover of the satellite's service link, the terminal cannot distinguish the SSBs from the two satellites, the terminal may not be able to detect the SSB of the next satellite providing service, or the terminal may reconnect to the original satellite after measurement.

[0052] Based on this, in various embodiments of the present application, while performing a satellite service link handover without changing the PCI, a network device sends first information to a terminal; wherein the terminal is located in an overlapping coverage area between a first satellite and a second satellite after the handover; the first information is used to determine the SSB of the second satellite, and includes at least a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite; while performing a satellite service link handover without changing the PCI, the terminal receives the first information sent by the network device and detects the SSB of the second satellite based on the first information. In the above solution, the network device sends the first information to the terminal to indicate the second SSB index corresponding to the second satellite, enabling the terminal to determine the SSB of the second satellite based on the second SSB index corresponding to the second satellite, thereby accurately detecting the SSB of the second satellite, connecting to the second satellite, and completing downlink synchronization. This not only prevents the terminal from repeatedly accessing the first satellite due to a small RSRP difference between the two satellites, but also avoids introducing Layer 3 handover and modifying the network device configuration, saving additional signaling overhead and reducing power consumption.

[0053] The present application will be described in further detail below with reference to the accompanying drawings and embodiments.

[0054] An embodiment of the present application provides a communication method, which is applied to a network device. The network device can communicate with a satellite without changing the PCI. The network device includes a ground base station in an NTN architecture without changing the PCI. As shown in FIG2 , the method includes:

[0055] Step 201: Sending first information to a terminal while not changing the PCI and performing satellite service link switching.

[0056] The terminal is located in an overlapping coverage area of ​​the first satellite and the switched second satellite; the first information is used to determine the SSB of the second satellite, and at least includes a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite.

[0057] Here, while performing a satellite service link handover without changing the PCI, the network device determines first information and sends the first information to the terminal. The first information may include a correspondence between satellites and SSB indexes, including at least the identifier of the first satellite and its corresponding first SSB index, and the identifier of the second satellite and its corresponding second SSB index. The first satellite is the satellite covering the cell corresponding to the PCI before the satellite service link handover, and the second satellite is the satellite covering the cell corresponding to the PCI after the satellite service link handover. During the satellite service link handover, the coverage areas of the first and second satellites overlap for a period of time. The service link handover can be understood as a soft handover of the service link. The first SSB index and the second SSB index are different and are used to distinguish SSBs from different satellites. The first SSB index generally refers to the SSB index corresponding to the first satellite, and the second SSB index generally refers to the SSB index corresponding to the second satellite. There is at least one first SSB index and there is also at least one second SSB index. The first SSB index and the second SSB index can correspond to the same SSB or different SSBs. In other words, the same SSB can correspond to different SSB indexes, and / or one SSB can correspond to one SSB index.

[0058] For example, without changing the PCI and establishing a communication connection between the first satellite and the terminal in the cell corresponding to the PCI, the network device determines the SSB required to cover the cell corresponding to the PCI; in the process of executing the satellite service link switching, the network device uses different SSB indexes (first SSB index, second SSB index) to associate the SSB required to cover the cell corresponding to the PCI to the first satellite and the second satellite respectively, and sends the first information to the terminal.

[0059] Specifically, for a group of SSBs that may contain one or more SSBs (for example, M SSBs, where M is a positive integer), the network device can configure a different SSB index for each SSB; when the cell corresponding to the coverage PCI only requires a single SSB, the network device selects one of the group of SSBs, and associates the first SSB index and the second SSB index of the SSB to the first satellite and the second satellite, and indicates to the terminal the correspondence between the two satellites and the SSB indexes; when the cell corresponding to the coverage PCI requires multiple SSBs, for example, the number is N (N≤M), and N is a positive integer, the network device selects N SSBs from a group of SSBs, associates the first SSB index and the second SSB index of each SSB in the N SSBs to the first satellite and the second satellite, and indicates to the terminal the correspondence between the two satellites and the different SSB indexes of each SSB in the N SSBs.

[0060] It should be noted that since the coverage areas of the first satellite and the second satellite will overlap for a period of time during the satellite service link switching process, the terminal connected to the first satellite needs to detect the SSB of the first satellite before the second satellite starts to provide services. Therefore, the first information includes the first SSB index corresponding to the first satellite; when the second satellite starts to provide services, the terminal connected to the second satellite needs to detect the SSB corresponding to the second SSB index based on the second SSB index corresponding to the second satellite contained in the first information.

[0061] Considering that the communication distance in the NTN scenario is very large and the positions of the first satellite and the second satellite are different, it is very likely that the time delay difference between the two satellites (the first satellite and the second satellite) and the terminal is large, so it is difficult to always receive the SSB according to the duration of the SMTC measurement window (for example, 5 milliseconds). Based on this, in order to ensure that the terminal can detect the SSB of the second satellite and avoid frequently compensating for time offsets through network devices, in one embodiment, the first information also includes a time offset; wherein,

[0062] The time offset represents the time offset of the system frame number (SFN) of the first frame relative to the SFN of the second frame. The first frame represents the frame where the SSB corresponding to the second SSB index is located, and the second frame represents the frame where the SSB corresponding to the first SSB index is located.

[0063] Here, the time offset is used for the terminal to determine the time for detecting the SSB of the second satellite. The time for detecting the SSB of the second satellite can also be understood as the reception time of the SSB of the second satellite.

[0064] The time offset is also called an offset parameter. The time offset can be described by the number of subframes or time slots of the offset. For example, the time offset can be the number of subframes or time slots by which the SFN of the first frame is offset relative to the SFN of the second frame.

[0065] In order to ensure that the terminal can detect the SSB of the second satellite and avoid the terminal failing to detect the SSB of the second satellite due to different satellite positions and satellite movement, in one embodiment, the time offset is a fixed time offset, or the time offset is determined based on the transmission delay difference; wherein,

[0066] The transmission delay difference represents the time difference between the delay of transmitting the first SSB to the terminal via the first satellite and the delay of transmitting the second SSB to the terminal via the second satellite.

[0067] Here, the network device can dynamically determine the time offset based on the transmission delay difference; the network device can also configure a fixed time offset in a semi-static manner. It should be noted that when the network device is configured with the time offset, there is no need to restrict the terminal from receiving the SSBs of two satellites within the duration of the same SSB measurement timing configuration (SMTC) measurement window. In other words, the terminal can detect the SSB of the first satellite within the duration of one SMTC measurement window and then detect the SSB of the second satellite within the duration of another new SMTC measurement window.

[0068] When the time offset included in the first information is a fixed time offset, each time the satellite service link switches, the terminal determines the reception time of the SSB of the second satellite based on the fixed time offset and detects the SSB of the second satellite at the determined reception time. If the actual transmission delay difference varies each time the satellite service link switches, the network device needs to perform time domain compensation on the feeder link based on the actual transmission delay difference to avoid errors in the time when the terminal detects the SSB of the second satellite, thereby ensuring that the terminal can detect the SSB of the second satellite within the configured SSB reception time. Time domain compensation can include the network device pre-adjusting the transmission time of the SSB of the second satellite or adjusting the time when the second satellite forwards the SSB before sending the SSB of the second satellite to compensate for the error caused by the fixed time offset based on the actual transmission delay difference.

[0069] In actual application, when the transmission delay difference is greater than or equal to the duration of an SMTC measurement window, the network device determines the time offset based on the transmission delay difference and indicates the time offset to the terminal. For example, the network device indicates to the terminal the number of subframes or time slots by which the SFN of the first frame is offset from the SFN of the second frame. The first frame represents the frame in which the SSB corresponding to the second SSB index is located, and the second frame represents the frame in which the SSB corresponding to the first SSB index is located. Considering the mobility of the satellite, the time offset can be indicated in the following two ways:

[0070] Method 1: When the network device indicates the second SSB index corresponding to the second satellite to the terminal, the corresponding signaling or message also carries the time offset corresponding to the second SSB index. Since satellites are constantly moving and the position of the same satellite is different at different times, the corresponding time offset needs to be configured according to the transmission delay difference during each satellite service link switching process. If the signaling received by the terminal carries both the second SSB index corresponding to the second satellite and the time offset corresponding to the second SSB index, including the second SSB index corresponding to the second satellite, then the terminal detects or receives the SSB of the second satellite at a time when the SFN of the second frame is offset backward by the time offset (SFN of the second frame + offset).

[0071] Method 2: The network device semi-statically configures a fixed time offset for the cell corresponding to the PCI, that is, during each satellite service link switching process, the terminal determines the reception time of the SSB of the second satellite based on the fixed time offset, and detects or receives the SSB of the second satellite at the determined reception time; if the transmission delay difference changes during each satellite service link switching process, the network device needs to perform time domain compensation in the feeder link according to the actual transmission delay difference to avoid errors in the time when the terminal detects the SSB of the second satellite, thereby ensuring that the terminal can detect the SSB of the second satellite within the configured SSB reception time.

[0072] Through the above method, when the satellite service link switching occurs in the same half of the static service cell, the terminal can be instructed to start detecting the offset time of the SSB of the second satellite relative to the SSB of the first satellite through signaling containing the time offset, thereby avoiding the terminal being unable to detect the SSB of the second satellite due to different satellite positions and satellite movements, so that the terminal located in the overlapping coverage area can accurately connect to the second satellite and complete uplink and downlink synchronization.

[0073] In the case where it is necessary to limit the terminal to detecting the SSBs of two satellites within the duration of the same SMTC measurement window, if the transmission delay difference is too large, for example, exceeding 5 milliseconds, it will not be possible to ensure that the terminal can detect the SSBs of the two satellites within the duration of the same SMTC measurement window. Based on this, in order to ensure that the terminal can detect the SSBs of the two satellites within the duration of the same SMTC measurement window, in one embodiment, the method further includes:

[0074] When the transmission delay difference is greater than or equal to the first threshold, time domain compensation is performed on the feeder link based on the transmission delay difference; wherein,

[0075] The transmission delay difference represents the time difference between the delay of the first SSB being transmitted to the terminal via the first satellite and the delay of the second SSB being transmitted to the terminal via the second satellite; the first threshold represents the duration of the SMTC measurement window.

[0076] Here, if the transmission delay difference is greater than or equal to the first threshold, if it is necessary to limit the terminal from detecting the SSBs of two satellites within the duration of the same SMTC measurement window, then the network device performs time domain compensation on the feeder link based on the transmission delay difference before sending the SSB of the second satellite. For example, the transmission time of the SSB of the second satellite is pre-adjusted, or the time when the second satellite forwards the SSB is adjusted. Time domain compensation can also be understood as time domain pre-compensation.

[0077] Considering that the terminal connected to the second satellite needs to use the auxiliary information of the second satellite during uplink synchronization, in order to enable the terminal connected to the second satellite to achieve uplink synchronization, the network device also needs to send the auxiliary information of the second satellite to the terminal. Based on this, in one embodiment, the method further includes:

[0078] Sending a first message to the terminal via the service link of the first satellite; wherein,

[0079] The first message carries assistance information of the second satellite.

[0080] Here, before the first satellite ends its service, the network device sends a first message to the terminal through the service link of the first satellite.

[0081] The first message may be a system message, for example, a System Information Block (SIB) 19 message. The auxiliary information may also be referred to as satellite auxiliary information; the auxiliary information primarily includes satellite ephemeris information, common TA parameters, K_offset, and other parameters used for NTN uplink synchronization. The auxiliary information may be configured in the NTN-specific parameters indicated by SIB 19.

[0082] It should be noted that in the embodiment of the present application, the network device directly indicates the correspondence between the satellite and the SSB index to the terminal through the first information, and sends the auxiliary information of the second satellite to the terminal through different SIB19 messages, as well as the auxiliary information of the first satellite. In other words, the SSB index of an SSB or a group of SSBs associated with the two satellites will correspond to different SIB19 contents, so that after the terminal detects the SSB of the second satellite, it can establish uplink synchronization with the second satellite through a new SIB19 message. In addition, the auxiliary information of the first satellite does not need to be associated with the first SSB index, and the auxiliary information of the second satellite does not need to be associated with the second SSB index, so there is no need to change the format of the SIB19 message.

[0083] Before the network device sends the SSB of the second satellite, it is also necessary to indicate to the terminal relevant information about the start of service of the second satellite. Based on this, in one embodiment, the first information is carried in the first signaling, and the first signaling also carries the time information of the start of service of the second satellite, or carries the time interval relative to the time when the first satellite starts service.

[0084] Here, the time interval relative to the time when the first satellite starts serving refers to a time interval shifted backward from the time when the first satellite starts serving.

[0085] In the embodiment of the present application, signaling overhead can be saved by carrying the first information through the first signaling.

[0086] In order to save signaling overhead, the network device can carry the first information and the auxiliary information of the two satellites through the same SIB19 message. Based on this, in one embodiment, the first information is carried in the second message, wherein,

[0087] The second message is sent through the service link of the first satellite, and the second message also carries the auxiliary information of the first satellite and the auxiliary information of the second satellite.

[0088] Here, before the first satellite ends its service, the network device sends a second message to the terminal via the service link of the first satellite. The second message may be a system message, for example, including a SIB19 message, where the SIB19 message is a new SIB19 message. In the second message, the assistance information of the first satellite may be associated with the first SSB index, and the assistance information of the second satellite may be associated with the second SSB index.

[0089] When the first information and the assistance information of two satellites are carried in the same SIB19 message, the network device needs to indicate the remaining service time of the first satellite to the terminal. Based on this, in one embodiment, the method further includes:

[0090] A third message is sent to the terminal, where the third message is used to indicate a remaining service time of the first satellite.

[0091] Here, before the first satellite ends its service, the network device may further send a third message to the terminal through the service link of the first satellite.

[0092] The third message may be the same as or different from the second message. For example, the third message may be the second message, that is, the first information, the assistance information of the two satellites, and the remaining service time of the first satellite are carried in the same system message (such as a SIB19 message). For another example, the third message may be another system message, such as another SIB19 message; the message format of the SIB19 message does not need to be changed; for example, t-service-r17 under the configuration parameters for the first satellite in the SIB19 message is used to indicate the remaining service time of the first satellite, so that after receiving the SIB19 message carrying the first information and the assistance information of the two satellites, the terminal also re-acquires the SIB19 message carrying the remaining service time of the first satellite, so as to connect to the second satellite before the first satellite ends its service.

[0093] Correspondingly, an embodiment of the present application further provides a communication method, which is applied to a terminal. As shown in FIG3 , the method includes:

[0094] Step 301: Receive first information sent by a network device while the PCI is not changed and a satellite service link switch is executed.

[0095] The terminal is located in an overlapping coverage area of ​​the first satellite and the switched second satellite; the first information at least includes a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite.

[0096] Step 302: Detect the SSB of the second satellite based on the first information.

[0097] Here, the terminal detects the SSB of the second satellite based on the second SSB index included in the first information to achieve downlink synchronization.

[0098] In order to ensure that the terminal can detect the SSB of the second satellite and avoid the terminal failing to detect the SSB of the second satellite due to different satellite positions and satellite movement, in one embodiment, the first information further includes a time offset; wherein,

[0099] The time offset represents the time offset of the SFN of the first frame relative to the SFN of the second frame. The first frame represents the frame where the SSB corresponding to the second SSB index is located, and the second frame represents the frame where the SSB corresponding to the first SSB index is located.

[0100] Here, the terminal determines the reception time of the SSB of the second satellite according to the time offset, and detects the SSB of the second satellite at the determined reception time.

[0101] In order to ensure that the terminal can detect the SSB of the second satellite, in one embodiment, the time offset is a fixed time offset, or the time offset is determined based on the transmission delay difference; wherein,

[0102] The transmission delay difference represents the time difference between the delay of transmitting the first SSB to the terminal via the first satellite and the delay of transmitting the second SSB to the terminal via the second satellite.

[0103] Considering that the terminal connected to the second satellite needs to use the auxiliary information of the second satellite during uplink synchronization, in order to enable the terminal connected to the second satellite to achieve uplink synchronization, the network device also needs to send the auxiliary information of the second satellite to the terminal. Based on this, in one embodiment, the method further includes:

[0104] receiving a first message sent by the network device; wherein,

[0105] The first message carries assistance information of the second satellite.

[0106] Here, the first message is sent by the network device through the service link of the first satellite.

[0107] Before the network device sends the SSB of the second satellite, it is also necessary to indicate to the terminal information related to the time when the second satellite starts service. In order to save signaling overhead, in one embodiment, the first information is carried in the first signaling, and the first signaling also carries the time information when the second satellite starts service, or carries the time interval relative to the time when the first satellite starts service.

[0108] Here, when the terminal receives the first signaling, it determines the time when the second satellite starts service and the second SSB index corresponding to the second satellite by decoding the first signaling, and detects the SSB associated with the satellite service link of the second satellite based on the second SSB index corresponding to the second satellite; after successfully decoding the SSB of the second satellite, it obtains downlink synchronization, re-obtains the SIB19 message, obtains the auxiliary information of the second satellite contained in the SIB19 message, and establishes uplink synchronization with the second satellite based on the auxiliary information of the second satellite.

[0109] In order to save signaling overhead, the network device may indicate the correspondence between the satellite and the SSB index and the satellite's auxiliary information to the terminal through a second message. Based on this, in one embodiment, the first information is carried in the second message, wherein:

[0110] The second message is sent through the service link of the first satellite; the second message also carries the auxiliary information of the first satellite and the auxiliary information of the second satellite.

[0111] Here, the terminal receives a second message sent by the network device through the service link of the first satellite, and the second message may include a SIB19 message; obtains the first SSB index corresponding to the first satellite, the second SSB index corresponding to the second satellite, the auxiliary information associated with the first SSB index, and the auxiliary information associated with the second SSB index carried in the second message; before the second satellite starts to provide service, the terminal detects the SSB of the first satellite according to the first SSB index to achieve downlink synchronization, and establishes uplink synchronization with the first satellite according to the auxiliary information associated with the first SSB index; when the second satellite starts to provide service, the terminal connects to the second satellite, detects the SSB of the second satellite according to the second SSB index to achieve downlink synchronization, and establishes uplink synchronization with the second satellite according to the auxiliary information associated with the second SSB index.

[0112] In order to enable the terminal to know the remaining service time of the first satellite and thus determine the time when the second satellite starts service, after the network device sends the second message to the terminal, it also indicates the remaining service time of the first satellite to the terminal. Based on this, in one embodiment, the method further includes:

[0113] A third message sent by the network device is received, where the third message is used to indicate a remaining service time of the first satellite.

[0114] The following further illustrates the embodiment of the present application with reference to the interactive flow diagram.

[0115] Application scenario 1: Indicating the first information and the time when the second satellite starts service through the first signaling

[0116] The communication shown in Figure 4 includes:

[0117] Step 1: In a process of performing satellite service link switching without changing PCI, the network device sends a first signaling to the terminal, and the terminal receives the first signaling.

[0118] The terminal is located in the overlapping coverage area of ​​the first satellite and the second satellite after switching; the first signaling carries first information; the first signaling also carries time information when the second satellite starts service, or carries the time interval relative to the time when the first satellite starts service; the first information is used to determine the SSB of the second satellite, including at least the first satellite and the corresponding first SSB index, and the second satellite and the corresponding second SSB index.

[0119] In one embodiment, the first information also includes a time offset; wherein,

[0120] The time offset represents the time offset of the SFN of the first frame relative to the SFN of the second frame. The first frame represents the frame where the SSB corresponding to the second SSB index is located, and the second frame represents the frame where the SSB corresponding to the first SSB index is located.

[0121] In one embodiment, the time offset is a fixed time offset, or the time offset is determined based on a transmission delay difference; wherein,

[0122] The transmission delay difference represents the time difference between the delay of transmitting the first SSB to the terminal via the first satellite and the delay of transmitting the second SSB to the terminal via the second satellite.

[0123] Step 2: The network device sends a first message to the terminal through the service link of the first satellite, and the terminal receives the first message.

[0124] The first message carries auxiliary information for the second satellite. The auxiliary information primarily includes satellite ephemeris information, common TA parameters, K_offset, and other parameters used for NTN uplink synchronization. The auxiliary information can be configured in the NTN-specific parameters indicated by SIB19.

[0125] It should be noted that step 1 and step 2 can be performed in parallel or partially in sequence.

[0126] Step 3: The terminal determines the SSB corresponding to the second SSB index according to the second SSB index included in the first information, and obtains the SSB of the second satellite.

[0127] Step 4: The network device determines whether the terminal is required to detect the SSBs of two satellites within the duration of the same SMTC measurement window.

[0128] Among them, when the terminal is required to detect the SSBs of two satellites within the duration of the same SMTC measurement window, execute steps 5 to 8; when the terminal is not required to detect the SSBs of two satellites within the duration of the same SMTC measurement window, execute steps 6 to 8.

[0129] Step 5: When the transmission delay difference is greater than or equal to the first threshold, the network device performs time domain compensation on the feeder link based on the transmission delay difference.

[0130] The transmission delay difference represents the time difference between the delay of the first SSB being transmitted to the terminal via the first satellite and the delay of the second SSB being transmitted to the terminal via the second satellite; the first threshold represents the duration of the SMTC measurement window.

[0131] Among them, time domain compensation can be that the network device pre-adjusts the sending time of the SSB of the second satellite before sending the SSB of the second satellite, or adjusts the time when the second satellite forwards the SSB, so that the terminal can detect the SSBs of the two satellites within the duration of the same SMTC measurement window.

[0132] Step 6: The network device sends the SSB of the second satellite.

[0133] Step 7: The terminal receives the SSB corresponding to the second SSB index.

[0134] In the case where the first information also includes a time offset, the terminal further determines a reception time of the SSB of the second satellite according to the time offset, and receives the SSB corresponding to the second SSB index at the determined reception time.

[0135] It should be noted that, when the terminal is not required to detect the SSBs of two satellites within the duration of the same SMTC measurement window, the terminal can receive the SSB corresponding to the second SSB index within the duration of a new SMTC measurement window based on the time offset.

[0136] Step 8: The terminal establishes uplink synchronization with the second satellite according to the auxiliary information of the second satellite carried in the first message.

[0137] Application scenario 2: Indicating the first information and auxiliary information through the second message

[0138] The communication shown in Figure 5 includes:

[0139] Step 1: Without changing the PCI and in the process of performing satellite service link switching, the network device sends a second message to the terminal through the service link of the first satellite, and the terminal receives the second message.

[0140] The terminal is located in an overlapping coverage area of ​​the first satellite and the switched second satellite; the second message carries the first information; the second message carries at least the first information, and also carries auxiliary information of the first satellite and auxiliary information of the second satellite; the first information is used to determine the SSB of the second satellite, and includes at least the first satellite and the corresponding first SSB index, and the second satellite and the corresponding second SSB index.

[0141] The auxiliary information mainly includes satellite ephemeris information, common TA parameters, K_offset and other parameters used for NTN uplink synchronization. The auxiliary information can be configured in the NTN-specific parameters indicated by SIB19.

[0142] In one embodiment, the first information also includes a time offset; wherein the time offset represents the time offset of the SFN of the first frame relative to the SFN of the second frame, the first frame represents the frame where the SSB corresponding to the second SSB index is located, and the second frame represents the frame where the SSB corresponding to the first SSB index is located.

[0143] In one embodiment, the time offset is a fixed time offset, or the time offset is determined based on a transmission delay difference; wherein the transmission delay difference represents the time difference between the delay of the first SSB being transmitted to the terminal via the first satellite and the delay of the second SSB being transmitted to the terminal via the second satellite.

[0144] Step 2: The network device sends a third message to the terminal through the service link of the first satellite, and the terminal receives the third message.

[0145] The third message is used to indicate the remaining service time of the first satellite.

[0146] Step 3: The terminal determines the SSB of the second satellite according to the second SSB index included in the first information.

[0147] Step 4: The network device determines whether the terminal is required to detect the SSBs of two satellites within the duration of the same SMTC measurement window.

[0148] Among them, when the terminal is required to detect the SSBs of two satellites within the duration of the same SMTC measurement window, execute steps 5 to 8; when the terminal is not required to detect the SSBs of two satellites within the duration of the same SMTC measurement window, execute steps 6 to 8.

[0149] Step 5: When the transmission delay difference is greater than or equal to the first threshold, the network device performs time domain compensation on the feeder link based on the transmission delay difference.

[0150] The transmission delay difference represents the time difference between the delay of the first SSB being transmitted to the terminal via the first satellite and the delay of the second SSB being transmitted to the terminal via the second satellite; the first threshold represents the duration of the SMTC measurement window.

[0151] Step 6: The network device sends the SSB of the second satellite.

[0152] Step 7: The terminal receives the SSB corresponding to the second SSB index.

[0153] In the case where the first information also includes a time offset, the terminal further determines a reception time of the SSB of the second satellite according to the time offset, and receives the SSB corresponding to the second SSB index at the determined reception time.

[0154] It should be noted that, when the terminal is not required to detect the SSBs of two satellites within the duration of the same SMTC measurement window, the terminal can receive the SSB corresponding to the second SSB index within the duration of a new SMTC measurement window based on the time offset.

[0155] Step 8: The terminal establishes uplink synchronization with the second satellite according to the auxiliary information of the second satellite carried in the second message.

[0156] The present application is described in further detail below with reference to application examples.

[0157] Application Example 1

[0158] For a terminal located in the same geographic area, the currently serving first satellite (satellite #1) and the upcoming second satellite (satellite #2) are connected to the same network device. Assuming the network device has configured the same single SSB for both satellites covering the current serving cell, the network device may configure the first SSB index of the first satellite to 0, associating SSB index 0 with the first satellite; and configure the second SSB index of the second satellite to 1, associating SSB index 1 with the second satellite. Before the service link communication of the first satellite is interrupted, the network device sends a first signaling to the terminal. The first signaling carries first information and information about the time when the second satellite begins service. The first information includes at least satellite #1 and its corresponding SSB index 0, as well as satellite #2 and its corresponding SSB index 1.

[0159] The network device configures auxiliary information related to satellite #2 in the SIB19 message. The auxiliary information includes parameters such as ephemeris information, common TA, and K_offset.

[0160] The terminal receives the first signaling sent by the network device, determines that the SSB index required to connect to the second satellite (satellite #2) is 1, finds the SSB corresponding to SSB index 1, and obtains the auxiliary information of the second satellite through the SIB19 message; the terminal successfully decodes the SSB and then establishes downlink synchronization with the second satellite, and establishes uplink synchronization based on the auxiliary information of the second satellite.

[0161] Furthermore, to ensure that the terminal can detect the second satellite's SSB within 5 milliseconds, if the reception time difference between SSB#0 and SSB#1 exceeds 5 ms due to satellite position change and movement, the network equipment must pre-compensate for the transmission delay difference in the feeder link. This ensures that the terminal can receive the second satellite's SSB within the configured SMTC measurement window. In practice, an SMTC measurement window lasts 5 ms.

[0162] Application Example 2:

[0163] For terminals in the same geographic area, the currently serving first satellite (satellite #1) and the upcoming second satellite (satellite #2) are connected to the same network device. Assuming the network device has configured the same single SSB for both satellites covering the current serving cell, the network device can configure the first SSB index of the first satellite to 0, associating SSB index 0 with the first satellite; and configure the second SSB index of the second satellite to 1, associating SSB index 1 with the second satellite. Before the service link communication of the first satellite is interrupted, the network device configures auxiliary information for the first satellite and the second satellite, respectively, and configures a new SIB19 message (second message). The new SIB19 message carries auxiliary information associated with satellite #1 and its corresponding SSB index 0 and SSB index 0, and auxiliary information associated with satellite #2 and its corresponding SSB index 1 and SSB index 1. The auxiliary information includes parameters such as ephemeris information, common TA, and K_offset.

[0164] The terminal obtains a new SIB19 message, determines in the new SIB19 message that the SSB index associated with satellite #2 is 1, and determines the auxiliary information associated with SSB index 1; the terminal receives the SSB corresponding to SSB index 1, successfully decodes the SSB, and then establishes downlink synchronization with the second satellite, and establishes uplink synchronization with the second satellite based on the auxiliary information associated with SSB index 1.

[0165] To ensure that the terminal can detect the second satellite's SSB within 5ms, if the reception time difference between SSB#0 and SSB#1 exceeds 5ms due to satellite position change and movement, the network equipment must pre-compensate for the transmission delay difference on the feeder link. This ensures that the terminal can receive the second satellite's SSB within the configured SMTC measurement window. In practice, an SMTC measurement window lasts 5ms.

[0166] Considering that the communication distance in the NTN scenario is very large and the positions of the first satellite and the second satellite are different, it is very likely that the time delay difference between the first satellite and the second satellite and the terminal is large. Therefore, it is difficult to always receive SSB according to the duration of the 5ms SMTC measurement window. For this problem, in order to avoid frequently compensating for time offsets through the network device side, the network device can detect the SSB of the second satellite by applying the solution of Example 3.

[0167] Application Example 3

[0168] For terminals in the same geographical area, the currently serving first satellite (satellite #1) and the upcoming second satellite (satellite #2) are connected to the same network device. Assuming that the network device configures the same SSB for the two satellites covering the current serving cell, the network device can configure the first SSB index of the first satellite to 0 and associate SSB index 0 with the first satellite; configure the second SSB index of the second satellite to 1 and associate SSB index 1 with the second satellite.

[0169] Before the service link communication of the first satellite is interrupted, the network device sends a first signaling message to the terminal. The first signaling message carries the first information, the time information when the second satellite starts service, and the time offset. The first information includes at least satellite #1 and its corresponding SSB index 0, and satellite #2 and its corresponding SSB index 1. The time offset, denoted as SSB1_offset, represents the time offset of the SFN of the frame containing SSB1 relative to the SFN of the frame containing SSB0. SSB0 is the SSB of the first satellite, and SSB1 is the SSB of the second satellite.

[0170] The network device configures the auxiliary information of the second satellite in the SIB19 message. The auxiliary information includes parameters related to uplink synchronization, such as ephemeris information, common TA, and K_offset.

[0171] The terminal receives the first signaling sent by the network device and obtains the first information and time offset carried in the first signaling; determines the SSB index 1 corresponding to the second satellite in the first information; determines the reception time of the SSB of the second satellite based on the time offset, for example, the reception time is the time domain position of (SFN of the frame where SSB0 is located + SSB1_offset); the terminal starts receiving the SSB corresponding to SSB index 1 at the time domain position of (SFN of the frame where SSB0 is located + SSB1_offset), and obtains the auxiliary information of the second satellite through the SIB19 message; the terminal successfully decodes the SSB and then establishes downlink synchronization with the second satellite, and establishes uplink synchronization with the second satellite based on the auxiliary information of the second satellite. As a result, the terminal can receive the SSB of the second satellite within the duration of the new SMTC measurement window. In actual application, the duration of an SMTC measurement window is 5ms.

[0172] In the above solution, the terminal determines the SSB of the second satellite based on the second SSB index corresponding to the second satellite, thereby accurately detecting the SSB of the second satellite to connect to the second satellite and complete downlink synchronization. This can not only prevent the terminal from repeatedly accessing the first satellite due to a small RSRP difference between the two satellites, but also avoid introducing layer 3 switching and modifying the configuration of network devices, saving additional signaling overhead and reducing power consumption.

[0173] In order to implement the communication method of the embodiment of the present application, the embodiment of the present application further provides a communication device, which is provided on a network device. As shown in FIG6 , the device includes:

[0174] The first sending unit 601 is configured to send first information to a terminal without changing the PCI and performing a satellite service link switch; wherein the terminal is located in an overlapping coverage area of ​​the first satellite and the second satellite after the switch; the first information is used to determine the SSB of the second satellite, and at least includes a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite.

[0175] In one embodiment, the first information also includes a time offset; wherein the time offset represents the time offset of the SFN of the first frame relative to the SFN of the second frame, the first frame represents the frame where the SSB corresponding to the second SSB index is located, and the second frame represents the frame where the SSB corresponding to the first SSB index is located.

[0176] In one embodiment, the time offset is a fixed time offset, or the time offset is determined based on a transmission delay difference; wherein the transmission delay difference represents the time difference between the delay of the first SSB being transmitted to the terminal via the first satellite and the delay of the second SSB being transmitted to the terminal via the second satellite.

[0177] In one embodiment, the apparatus further comprises:

[0178] A compensation unit is configured to perform time domain compensation in the feeder link based on the transmission delay difference when the transmission delay difference is greater than or equal to a first threshold; wherein the transmission delay difference represents the time difference between the delay of the first SSB transmitted to the terminal via the first satellite and the delay of the second SSB transmitted to the terminal via the second satellite; and the first threshold represents the duration of the SMTC measurement window.

[0179] In one embodiment, the apparatus further comprises:

[0180] The second sending unit is configured to send a first message to the terminal through the service link of the first satellite; wherein the first message carries the auxiliary information of the second satellite.

[0181] In one embodiment, the first information is carried in a first signaling, and the first signaling further carries time information when the second satellite starts serving, or carries a time interval relative to the time when the first satellite starts serving.

[0182] In one embodiment, the first information is carried in a second message, wherein the second message is sent via a service link of the first satellite, and the second message further carries auxiliary information of the first satellite and auxiliary information of the second satellite.

[0183] In one embodiment, the apparatus further comprises:

[0184] The third sending unit is configured to send a third message to the terminal, where the third message is used to indicate the remaining service time of the first satellite.

[0185] In actual application, the first sending unit 601, the second sending unit and the third sending unit can be implemented by a processor in the communication device in combination with a communication interface, and the compensation unit can be implemented by a processor in the communication device.

[0186] In order to implement the communication method of the embodiment of the present application, the embodiment of the present application further provides a communication device, which is provided on a terminal, as shown in FIG7 , and includes:

[0187] The first receiving unit 701 is configured to receive first information sent by a network device during a process of performing a satellite service link handover without changing a PCI; wherein the terminal is located in an overlapping coverage area of ​​a first satellite and a second satellite after the handover; and the first information includes at least a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite;

[0188] The detection unit 702 is configured to detect the SSB of the second satellite based on the first information.

[0189] In one embodiment, the first information also includes a time offset; wherein the time offset represents the time offset of the SFN of the first frame relative to the SFN of the second frame, the first frame represents the frame where the SSB corresponding to the second SSB index is located, and the second frame represents the frame where the SSB corresponding to the first SSB index is located.

[0190] In one embodiment, the time offset is a fixed time offset, or the time offset is determined based on a transmission delay difference; wherein the transmission delay difference represents the time difference between the delay of the first SSB being transmitted to the terminal via the first satellite and the delay of the second SSB being transmitted to the terminal via the second satellite.

[0191] In one embodiment, the apparatus further comprises:

[0192] The second receiving unit is configured to receive a first message sent by the network device; wherein the first message carries the auxiliary information of the second satellite.

[0193] In one embodiment, the first information is carried in a first signaling, and the first signaling further carries time information when the second satellite starts serving, or carries a time interval relative to the time when the first satellite starts serving.

[0194] In one embodiment, the first information is carried in a second message, wherein:

[0195] The second message is sent through the service link of the first satellite; the second message also carries the auxiliary information of the first satellite and the auxiliary information of the second satellite.

[0196] In one embodiment, the apparatus further comprises:

[0197] The third receiving unit is configured to receive a third message sent by the network device, where the third message is used to indicate the remaining service time of the first satellite.

[0198] In actual application, the first receiving unit 701, the second receiving unit and the third receiving unit can be implemented by a processor in the communication device in combination with a communication interface, and the detection unit 702 can be implemented by a processor in the communication device.

[0199] It should be noted that the fault prediction device provided in the above embodiment uses the division of the aforementioned program modules as an example only for fault prediction purposes. In actual applications, the aforementioned processes can be assigned to different program modules as needed, i.e., the internal structure of the device can be divided into different program modules to complete all or part of the aforementioned processes. Furthermore, the fault prediction device provided in the above embodiment and the fault prediction method embodiment are based on the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0200] Based on the hardware implementation of the above program modules, and in order to implement the method on the network device side of the embodiment of the present application, the embodiment of the present application further provides a network device, as shown in FIG8 , where the network device 800 includes:

[0201] The first communication interface 801 is capable of exchanging information with other network nodes;

[0202] The first processor 802 is connected to the first communication interface 801 to implement information exchange with other network nodes and is used to execute the methods provided by one or more technical solutions on the network device side when running a computer program. The computer program is stored in the first memory 803.

[0203] Specifically, the first communication interface 801 is configured to send first information to the terminal without changing the PCI and performing the satellite service link switching process; wherein,

[0204] The terminal is located in an overlapping coverage area of ​​a first satellite and a second satellite after switching; the first information is used to determine the SSB of the second satellite, and includes at least a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite.

[0205] In one embodiment, the first information also includes a time offset; wherein,

[0206] The time offset represents the time offset of the SFN of the first frame relative to the SFN of the second frame. The first frame represents the frame where the SSB corresponding to the second SSB index is located, and the second frame represents the frame where the SSB corresponding to the first SSB index is located.

[0207] In one embodiment, the time offset is a fixed time offset, or the time offset is determined based on a transmission delay difference; wherein,

[0208] The transmission delay difference represents the time difference between the delay of transmitting the first SSB to the terminal via the first satellite and the delay of transmitting the second SSB to the terminal via the second satellite.

[0209] In one embodiment, the first processor 802 is configured to perform time domain compensation on the feeder link based on the transmission delay difference when the transmission delay difference is greater than or equal to the first threshold; wherein,

[0210] The transmission delay difference represents the time difference between the delay of the first SSB being transmitted to the terminal via the first satellite and the delay of the second SSB being transmitted to the terminal via the second satellite; the first threshold represents the duration of the SMTC measurement window.

[0211] In one embodiment, the first communication interface 801 is further configured to send a first message to the terminal via a service link of the first satellite; wherein the first message carries auxiliary information of the second satellite.

[0212] In one embodiment, the first information is carried in a first signaling, and the first signaling further carries time information when the second satellite starts serving, or carries a time interval relative to the time when the first satellite starts serving.

[0213] In one embodiment, the first information is carried in a second message, wherein:

[0214] The second message is sent through the service link of the first satellite, and the second message also carries the auxiliary information of the first satellite and the auxiliary information of the second satellite.

[0215] In one embodiment, the first communication interface 801 is further configured to send a third message to the terminal, where the third message is used to indicate the remaining service time of the first satellite.

[0216] It should be noted that the specific processing process of the first processor 802 and the first communication interface 801 can be understood by referring to the above method.

[0217] Of course, in actual use, the various components in network device 800 are coupled together via bus system 804. It will be appreciated that bus system 804 is configured to enable communication between these components. In addition to a data bus, bus system 804 also includes a power bus, a control bus, and a status signal bus. However, for clarity, in FIG8 , all of these buses are labeled as bus system 804.

[0218] The first memory 803 in the embodiment of the present application is configured to store various types of data to support the operation of the network device 800. Examples of such data include: any computer program for operating on the network device 800.

[0219] The methods disclosed in the above embodiments of the present application can be applied to the first processor 802 or implemented by the first processor 802. The first processor 802 may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method can be completed by hardware integrated logic circuits or software instructions in the first processor 802. The above first processor 802 may be a general-purpose processor, a digital signal processor (DSP), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The first processor 802 can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present application. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of the present application can be directly implemented as being executed by a hardware decoding processor, or can be executed by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium located in the first memory 803. The first processor 802 reads the information in the first memory 803 and completes the steps of the above method in combination with its hardware.

[0220] In an exemplary embodiment, the network device 800 can be implemented by one or more application-specific integrated circuits (ASICs), DSPs, programmable logic devices (PLDs), complex programmable logic devices (CPLDs), field-programmable gate arrays (FPGAs), general-purpose processors, controllers, microcontrollers (MCUs), microprocessors, or other electronic components to perform the aforementioned method.

[0221] Based on the hardware implementation of the above program modules, and in order to implement the method on the terminal side of the embodiment of the present application, the embodiment of the present application further provides a terminal, as shown in FIG9 , the terminal 900 includes:

[0222] The second communication interface 901 is capable of exchanging information with other network nodes;

[0223] The second processor 902 is connected to the second communication interface 901 to implement information exchange with other network nodes and is used to execute the methods provided by one or more technical solutions on the second electronic device side when running a computer program. The computer program is stored in the second memory 903.

[0224] Specifically, the second communication interface 901 is configured to receive first information sent by a network device during a process of performing a satellite service link handover without changing a PCI; wherein the terminal is located in an overlapping coverage area of ​​the first satellite and a second satellite after the handover; and the first information includes at least a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite.

[0225] The second processor 902 is configured to detect the SSB of the second satellite based on the first information.

[0226] In one embodiment, the first information also includes a time offset; wherein,

[0227] The time offset represents the time offset of the SFN of the first frame relative to the SFN of the second frame. The first frame represents the frame where the SSB corresponding to the second SSB index is located, and the second frame represents the frame where the SSB corresponding to the first SSB index is located.

[0228] In one embodiment, the time offset is a fixed time offset, or the time offset is determined based on a transmission delay difference; wherein,

[0229] The transmission delay difference represents the time difference between the delay of transmitting the first SSB to the terminal via the first satellite and the delay of transmitting the second SSB to the terminal via the second satellite.

[0230] In one embodiment, the second communication interface 901 is further configured to receive a first message sent by the network device; wherein the first message carries the auxiliary information of the second satellite.

[0231] In one embodiment, the first information is carried in a first signaling, and the first signaling further carries time information when the second satellite starts serving, or carries a time interval relative to the time when the first satellite starts serving.

[0232] In one embodiment, the first information is carried in a second message, wherein:

[0233] The second message is sent through the service link of the first satellite; the second message also carries the auxiliary information of the first satellite and the auxiliary information of the second satellite.

[0234] In one embodiment, the second communication interface 901 is further configured to receive a third message sent by the network device, where the third message is used to indicate the remaining service time of the first satellite.

[0235] It should be noted that the specific processing process of the second processor 902 and the second communication interface 901 can be understood by referring to the above method.

[0236] Of course, in actual use, the various components in terminal 900 are coupled together via bus system 904. It will be appreciated that bus system 904 is configured to enable communication between these components. In addition to a data bus, bus system 904 also includes a power bus, a control bus, and a status signal bus. However, for clarity, in FIG9 , all of these buses are labeled as bus system 904.

[0237] The second memory 903 in the embodiment of the present application is configured to store various types of data to support the operation of the terminal 900. Examples of such data include: any computer program for operating on the terminal 900.

[0238] The methods disclosed in the above embodiments of the present application can be applied to or implemented by the second processor 902. The second processor 902 may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method can be completed by hardware integrated logic circuits or software instructions in the second processor 902. The above second processor 902 may be a general-purpose processor, a DSP, or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, etc. The second processor 902 can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present application. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of the present application can be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module may be located in a storage medium located in the second memory 903. The second processor 902 reads the information in the second memory 903 and, in conjunction with its hardware, completes the steps of the above method.

[0239] In an exemplary embodiment, the terminal 900 may be implemented by one or more ASICs, DSPs, PLDs, CPLDs, FPGAs, general-purpose processors, controllers, MCUs, Microprocessors, or other electronic components to perform the aforementioned methods.

[0240] It can be understood that the memory (first memory 803, second memory 903) of the embodiment of the present application can be a volatile memory or a non-volatile memory, and can also include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a magnetic random access memory (FRAM), a flash memory, a magnetic surface memory, an optical disc, or a compact disc read-only memory (CD-ROM); the magnetic surface memory can be a magnetic disk memory or a tape memory. The volatile memory can be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static random access memory (SRAM), synchronous static random access memory (SSRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct rambus random access memory (DRRAM).The memories described in the embodiments of this application are intended to include, but are not limited to, these and any other suitable types of memories.

[0241] In an exemplary embodiment, the present application also provides a storage medium, namely, a computer storage medium, specifically, a computer-readable storage medium, which, for example, includes a first memory 803 storing a computer program. The computer program can be executed by the first processor 802 of the network device 800 to complete the steps of the aforementioned network device-side method. For another example, the present application also provides a second memory 903 storing a computer program. The computer program can be executed by the second processor 902 of the terminal 900 to complete the steps of the aforementioned terminal-side method. The computer-readable storage medium can be a memory such as FRAM, ROM, PROM, EPROM, EEPROM, Flash Memory, magnetic surface storage, optical disk, or CD-ROM.

[0242] It should be noted that: "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0243] The term "and / or" herein simply describes an association relationship between associated objects, indicating that three relationships can exist. For example, "A and / or B" can represent the existence of A alone, the simultaneous existence of A and B, and the existence of B alone. Furthermore, the term "at least one" herein refers to any combination of at least two of any one or more of a plurality of items. For example, "at least one of A, B, and C" can represent any one or more elements selected from the set consisting of A, B, and C.

[0244] In addition, the technical solutions described in the embodiments of the present application can be arbitrarily combined without conflict.

[0245] The above description is merely a preferred embodiment of the present application and is not intended to limit the scope of protection of the present application.

Claims

1. A communication method, applied to a network device, comprising: In the process of not changing the physical cell identifier PCI and performing the satellite service link switching, first information is sent to the terminal; wherein, The terminal is located in the overlapping coverage area of ​​the first satellite and the switched second satellite; the first information is used to determine the synchronization signal block SSB of the second satellite, including at least a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite.

2. The method according to claim 1, wherein: The first information also includes a time offset; wherein, The time offset represents the time offset of the system frame number SFN of the first frame relative to the SFN of the second frame. The first frame represents the frame where the SSB corresponding to the second SSB index is located, and the second frame represents the frame where the SSB corresponding to the first SSB index is located.

3. The method according to claim 2, wherein: The time offset is a fixed time offset, or the time offset is determined based on a transmission delay difference; wherein, The transmission delay difference represents the time difference between the delay of transmitting the first SSB to the terminal via the first satellite and the delay of transmitting the second SSB to the terminal via the second satellite.

4. The method according to any one of claims 1 to 3, wherein: The method further comprises: When the transmission delay difference is greater than or equal to the first threshold, time domain compensation is performed in the feeder link based on the transmission delay difference; wherein, The transmission delay difference represents the time difference between the delay of the first SSB being transmitted to the terminal via the first satellite and the delay of the second SSB being transmitted to the terminal via the second satellite; the first threshold represents the duration of the SMTC measurement window of the SSB measurement timing configuration.

5. The method according to any one of claims 1 to 3, wherein: The method further comprises: Sending a first message to the terminal via the service link of the first satellite; wherein, The first message carries assistance information of the second satellite.

6. The method according to claim 5, wherein: The first information is carried in a first signaling, and the first signaling also carries time information when the second satellite starts to provide service, or carries a time interval relative to the time when the first satellite starts to provide service.

7. The method according to any one of claims 1 to 3, wherein: The first information is carried in a second message, wherein: The second message is sent through the service link of the first satellite, and the second message also carries the auxiliary information of the first satellite and the auxiliary information of the second satellite.

8. The method according to claim 7, wherein: The method further comprises: A third message is sent to the terminal, where the third message is used to indicate a remaining service time of the first satellite.

9. A communication method, applied to a terminal, the method comprising: In a process of performing satellite service link switching without changing the PCI, receiving first information sent by a network device; wherein the terminal is located in an overlapping coverage area of ​​the first satellite and the second satellite after switching; and the first information at least includes a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite; Based on the first information, the SSB of the second satellite is detected.

10. The method according to claim 9, wherein: The first information also includes a time offset; in, The time offset represents the time offset of the SFN of the first frame relative to the SFN of the second frame. The first frame represents the frame where the SSB corresponding to the second SSB index is located, and the second frame represents the frame where the SSB corresponding to the first SSB index is located.

11. The method according to claim 10, wherein: The time offset is a fixed time offset, or the time offset is determined based on a transmission delay difference; wherein, The transmission delay difference represents the time difference between the delay of transmitting the first SSB to the terminal via the first satellite and the delay of transmitting the second SSB to the terminal via the second satellite.

12. The method according to any one of claims 9 to 11, wherein: The method further comprises: receiving a first message sent by the network device; wherein, The first message carries assistance information of the second satellite.

13. The method according to claim 12, wherein: The first information is carried in a first signaling, and the first signaling also carries time information when the second satellite starts to provide service, or carries a time interval relative to the time when the first satellite starts to provide service.

14. The method according to any one of claims 9 to 11, wherein: The first information is carried in a second message, wherein: The second message is sent through the service link of the first satellite; the second message also carries the auxiliary information of the first satellite and the auxiliary information of the second satellite.

15. The method according to claim 14, wherein: The method further comprises: A third message sent by the network device is received, where the third message is used to indicate a remaining service time of the first satellite.

16. A communication device, comprising: The first sending unit is configured to send first information to the terminal without changing the PCI and performing the satellite service link switching process; wherein, The terminal is located in an overlapping coverage area of ​​a first satellite and a second satellite after switching; the first information is used to determine the SSB of the second satellite, and at least includes a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite.

17. A communication device, comprising: The first receiving unit is configured to receive first information sent by a network device without changing the PCI and performing a satellite service link switching process; wherein the terminal is located in an overlapping coverage area of ​​the first satellite and the second satellite after the switching; and the first information at least includes a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite; A detection unit is configured to detect the SSB of the second satellite based on the first information.

18. A network device comprising a first processor and a first communication interface, wherein: The first communication interface is configured to send first information to the terminal without changing the PCI and performing the satellite service link switching process; wherein, The terminal is located in an overlapping coverage area of ​​a first satellite and a second satellite after switching; the first information is used to determine the SSB of the second satellite, and at least includes a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite.

19. A terminal comprising a second processor and a second communication interface, wherein: The second communication interface is configured to receive first information sent by a network device without changing the PCI and performing a satellite service link switching process; wherein the terminal is located in an overlapping coverage area of ​​the first satellite and the second satellite after the switching; and the first information at least includes a first SSB index corresponding to the first satellite and a second SSB index corresponding to the second satellite; The second processor is configured to detect the SSB of the second satellite based on the first information.

20. A network device comprising a first processor and a first memory configured to store a computer program executable on the first processor, in, The first processor is configured to execute the steps of the method according to any one of claims 1 to 8 when running the computer program.

21. A terminal comprising a second processor and a second memory configured to store a computer program that can be run on the second processor, in, The second processor is configured to execute the steps of the method according to any one of claims 9 to 15 when running the computer program.

22. A storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the computer program implements the steps of the method according to any one of claims 1 to 8, or implements the steps of the method according to any one of claims 9 to 15.

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