A synchronization method and apparatus in a satellite network

Abstract

The application discloses a synchronization method and device in a satellite network, which is used for providing an uplink and downlink synchronization update scheme of a terminal when a cell identifier does not change while a satellite providing beam coverage for a region to which the terminal belongs changes, and providing an uplink and downlink synchronization update scheme of the terminal for the terminal uplink and downlink out-of-sync problem caused by the change of the satellite position. The method provided by the application comprises the following steps: determining that the cell identifiers of a first satellite cell and a second satellite cell are the same, wherein the first satellite cell is a cell currently serving a terminal; and performing a synchronization process of the terminal and the second satellite cell according to a time difference of a signal transmitted through the first satellite and the second satellite between the terminal and a base station, or according to a propagation time delay difference of the signal between the terminal and the first satellite and the second satellite.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a synchronization method and apparatus in a satellite network. Background Technology

[0002] Due to their unique geographical location, satellites offer advantages such as wide coverage, ease of deployment, and stable channels, which can compensate for the shortcomings of terrestrial networks. The integration of terrestrial and satellite networks has garnered widespread attention. Within satellite networks, low-Earth orbit (LEO) satellites, with their lower propagation latency and greater deployable resources, are currently a key research focus.

[0003] Based on the high-speed movement of low-Earth orbit satellites, two cell types were planned: quasi-earth fixed cells and earth-moving cells. A quasi-earth fixed cell refers to a satellite whose antenna angle is adjusted to project a fixed beam onto a specific area of ​​the ground for a period of time. For example... Figure 1 As shown, satellite a and satellite b fix the coverage areas 1 and 2 respectively before time t1 (t1-), and change the coverage areas 2 and 3 respectively at time t1 (t1+). Summary of the Invention

[0004] This application provides a synchronization method and apparatus in a satellite network, which provides a terminal uplink and downlink synchronization update scheme to address the problem of terminal uplink and downlink synchronization loss caused by changes in satellite location when the satellite providing beam coverage to the area to which the terminal belongs changes but the cell identifier does not change.

[0005] On the terminal side, an embodiment of this application provides a synchronization method in a satellite network, including:

[0006] It is determined that the cell identifiers of the first satellite cell and the second satellite cell are the same; wherein, the first satellite cell is the cell of the current serving terminal;

[0007] Based on the time difference between the signals transmitted between the terminal and the base station via the first satellite and the second satellite, or based on the propagation delay difference between the terminal and the first satellite and the second satellite, the synchronization process between the terminal and the second satellite cell is performed.

[0008] This method, when the cell identifiers of the first satellite cell and the second satellite cell are the same, wherein the first satellite cell is the cell of the currently serving terminal, performs a synchronization process between the terminal and the second satellite cell based on the time difference of the signals transmitted between the terminal and the base station through the first satellite and the second satellite, or based on the propagation delay difference of the signals between the terminal and the first satellite and the second satellite. Thus, when the satellite providing beam coverage for the area to which the terminal belongs changes from the first satellite to the second satellite but the cell identifier does not change (the first satellite cell and the second satellite cell are the same cell), this method provides a solution for the uplink and downlink synchronization update of the terminal caused by the change of the position of the second satellite that is now providing beam coverage, so that the terminal can synchronize with the second satellite cell.

[0009] In some implementations, the time difference between the terminal and the base station via the signals transmitted through the first satellite and the second satellite is determined by one or more of the following methods:

[0010] The terminal determines the reception time difference when it receives the same downlink signal transmitted by the base station through the first satellite and the second satellite, respectively.

[0011] The terminal subtracts the transmission time difference of the base station from the reception time difference of the different downlink signals received by the terminal from the base station through the first satellite and the second satellite respectively.

[0012] The terminal receives the reception time difference of the same uplink signal transmitted by the terminal through the first satellite and the second satellite, respectively, as detected by the base station.

[0013] The terminal receives the reception time difference of the different uplink signals transmitted by the terminal through the first satellite and the second satellite, respectively, detected by the base station, and subtracts the transmission time difference of the different uplink signals from the reception time difference.

[0014] In some implementations, the propagation delay difference of the signal between the terminal and the first and second satellites is determined by one or more of the following methods:

[0015] The terminal determines the time difference between receiving the same downlink signal sent by the first satellite and the second satellite;

[0016] The terminal determines the time difference between receiving different downlink signals sent by the first satellite and the second satellite, and subtracts the transmission time difference between the first satellite and the second satellite from the time difference.

[0017] The terminal receives a first reception time when the first satellite detects the uplink signal sent by the terminal, and a second reception time when the second satellite detects the same uplink signal sent by the terminal, and calculates the difference between the first reception time and the second reception time.

[0018] The terminal receives a first reception time when the first satellite detects an uplink signal sent by the terminal, and a second reception time when the second satellite detects different uplink signals sent by the terminal. The terminal calculates the difference between the first reception time and the second reception time, and subtracts the transmission time difference of the different uplink signals sent by the terminal from the difference.

[0019] In some implementations, prior to performing the synchronization process with the second satellite cell, the method further includes acquiring one or a combination of the following information:

[0020] The community signage remains unchanged;

[0021] The second satellite begins beam coverage of the area to which the terminal belongs;

[0022] Information on the time when the first satellite ceases beam coverage of the area to which the terminal belongs;

[0023] The time information or indication information for the terminal to begin the synchronization process with the second satellite cell;

[0024] Instructions to begin synchronizing with the second satellite cell;

[0025] The ephemeris information of the second satellite;

[0026] The common timing advance value information of the second satellite;

[0027] Downlink signal configuration information;

[0028] Uplink signal configuration information;

[0029] The base station transmits downlink signals via the first satellite and the second satellite respectively, using the transmission time difference information.

[0030] In some implementations, when one or a combination of the information is received, it is determined that a synchronization process between the terminal and the second satellite cell needs to be performed.

[0031] In some embodiments, the method further includes:

[0032] According to the network configuration, synchronization with the second satellite cell begins;

[0033] Alternatively, after the terminal obtains the updated timing advance value, it immediately begins to synchronize with the second satellite cell;

[0034] Alternatively, upon receiving an instruction from the network side, synchronization with the second satellite cell can begin.

[0035] On the network side, the synchronization method in a satellite network provided in this application includes:

[0036] It is determined that the cell identifiers of the first satellite cell and the second satellite cell are the same; wherein, the first satellite cell is the cell of the current serving terminal;

[0037] Signals are transmitted to the terminal via the first satellite and the second satellite, respectively, so that the terminal can obtain and perform a synchronization process with the second satellite cell based on the time difference between the signals transmitted between the terminal and the base station via the first satellite and the second satellite, or the propagation delay difference between the signal and the first satellite and the second satellite.

[0038] In some implementations, signal transmission to the terminal is performed via the first satellite and the second satellite, respectively, so that the terminal obtains the time difference between the signals transmitted through the first satellite and the second satellite between the terminal and the base station, including:

[0039] The same downlink signal is transmitted to the terminal via the first satellite and the second satellite respectively, so that the terminal determines the reception time difference of the same downlink signal transmitted via the first satellite and the second satellite respectively;

[0040] Different downlink signals are transmitted to the terminal via the first satellite and the second satellite respectively, and the transmission time difference of the different downlink signals is notified to the terminal, so that the terminal will subtract the transmission time difference of the different downlink signals from the reception time difference of the different downlink signals transmitted via the first satellite and the second satellite respectively.

[0041] The terminal receives the same uplink signal transmitted through the first satellite and the second satellite respectively, detects the reception time difference of the same uplink signal, and sends the reception time difference to the terminal.

[0042] The terminal receives different uplink signals transmitted through the first satellite and the second satellite, respectively, detects the reception time difference of the different uplink signals, and sends the reception time difference to the terminal.

[0043] In some implementations, signal transmission is performed with the terminal via the first satellite and the second satellite, respectively, so that the terminal obtains the propagation delay difference of the signal between the terminal and the first satellite and the second satellite, including:

[0044] The terminal can determine the time difference between receiving the same downlink signal from the first satellite and the second satellite by sending the same downlink signal to the terminal via the first satellite and the second satellite.

[0045] Different downlink signals and their transmission times are sent to the terminal via the first satellite and the second satellite, so that the terminal determines the time difference between receiving the different downlink signals sent by the first satellite and the second satellite, and subtracts the transmission time difference between the first satellite and the second satellite from the time difference.

[0046] The terminal receives the same uplink signal sent by the terminal through the first satellite and the second satellite, and sends the first reception time of the same uplink signal to the terminal through the first satellite, and sends the second reception time of the same uplink signal to the terminal through the second satellite, so that the terminal calculates the difference between the first reception time and the second reception time.

[0047] The terminal receives different uplink signals sent by the first satellite and the second satellite, and sends the first reception time of the uplink signal to the terminal via the first satellite and the second reception time of the uplink signal to the terminal via the second satellite. The terminal calculates the difference between the first reception time and the second reception time, and subtracts the transmission time difference of the different uplink signals sent by the terminal from the difference.

[0048] In some embodiments, the method further includes sending one or a combination of the following information to the terminal:

[0049] The community signage remains unchanged;

[0050] The second satellite begins beam coverage of the area to which the terminal belongs;

[0051] Information on the time when the first satellite ceases beam coverage of the area to which the terminal belongs;

[0052] The time information or indication information for the terminal to begin the synchronization process with the second satellite cell;

[0053] Instructions to begin synchronizing with the second satellite cell;

[0054] The ephemeris information of the second satellite;

[0055] The common timing advance value information of the second satellite;

[0056] Downlink signal configuration information;

[0057] Uplink signal configuration information;

[0058] The base station transmits downlink signals via the first satellite and the second satellite respectively, using the transmission time difference information.

[0059] On the terminal side, an embodiment of this application provides a synchronization device in a satellite network, including a memory, a transceiver, and a processor.

[0060] A memory for storing computer programs; a transceiver for sending and receiving data under the control of the processor; and a processor for reading the computer programs from the memory and performing the following operations:

[0061] It is determined that the cell identifiers of the first satellite cell and the second satellite cell are the same; wherein, the first satellite cell is the cell of the current serving terminal;

[0062] Based on the time difference between the signals transmitted between the terminal and the base station via the first satellite and the second satellite, or based on the propagation delay difference between the terminal and the first satellite and the second satellite, the synchronization process between the terminal and the second satellite cell is performed.

[0063] In some implementations, the time difference between the terminal and the base station via the signals transmitted through the first satellite and the second satellite is determined by one or more of the following methods:

[0064] The terminal determines the reception time difference when it receives the same downlink signal transmitted by the base station through the first satellite and the second satellite, respectively.

[0065] The terminal subtracts the transmission time difference of the base station from the reception time difference of the different downlink signals received by the terminal from the base station through the first satellite and the second satellite respectively.

[0066] The terminal receives the reception time difference of the same uplink signal transmitted by the terminal through the first satellite and the second satellite, respectively, as detected by the base station.

[0067] The terminal receives the reception time difference of the different uplink signals transmitted by the terminal through the first satellite and the second satellite, respectively, detected by the base station, and subtracts the transmission time difference of the different uplink signals from the reception time difference.

[0068] In some implementations, the propagation delay difference of the signal between the terminal and the first and second satellites is determined by one or more of the following methods:

[0069] The terminal determines the time difference between receiving the same downlink signal sent by the first satellite and the second satellite;

[0070] The terminal determines the time difference between receiving different downlink signals sent by the first satellite and the second satellite, and subtracts the transmission time difference between the first satellite and the second satellite from the time difference.

[0071] The terminal receives a first reception time when the first satellite detects the uplink signal sent by the terminal, and a second reception time when the second satellite detects the same uplink signal sent by the terminal, and calculates the difference between the first reception time and the second reception time.

[0072] The terminal receives a first reception time when the first satellite detects an uplink signal sent by the terminal, and a second reception time when the second satellite detects different uplink signals sent by the terminal. The terminal calculates the difference between the first reception time and the second reception time, and subtracts the transmission time difference of the different uplink signals sent by the terminal from the difference.

[0073] In some implementations, prior to performing the synchronization process with the second satellite cell, the processor is further configured to read the computer program in the memory and obtain one or a combination of the following information:

[0074] The community signage remains unchanged;

[0075] The second satellite begins beam coverage of the area to which the terminal belongs;

[0076] Information on the time when the first satellite ceases beam coverage of the area to which the terminal belongs;

[0077] The time information or indication information for the terminal to begin the synchronization process with the second satellite cell;

[0078] Instructions to begin synchronizing with the second satellite cell;

[0079] The ephemeris information of the second satellite;

[0080] The common timing advance value information of the second satellite;

[0081] Downlink signal configuration information;

[0082] Uplink signal configuration information;

[0083] The base station transmits downlink signals via the first satellite and the second satellite respectively, using the transmission time difference information.

[0084] In some implementations, when one or a combination of the information is received, the processor determines that a synchronization process between the terminal and the second satellite cell needs to be performed.

[0085] In some embodiments, the processor is further configured to read a computer program from the memory and perform the following operations:

[0086] According to the network configuration, synchronization with the second satellite cell begins;

[0087] Alternatively, after the terminal obtains the updated timing advance value, it immediately begins to synchronize with the second satellite cell;

[0088] Alternatively, upon receiving an instruction from the network side, synchronization with the second satellite cell can begin.

[0089] On the network side, this application provides a synchronization device in a satellite network, including a memory, a transceiver, and a processor.

[0090] A memory for storing computer programs; a transceiver for sending and receiving data under the control of the processor; and a processor for reading the computer programs from the memory and performing the following operations:

[0091] It is determined that the cell identifiers of the first satellite cell and the second satellite cell are the same; wherein, the first satellite cell is the cell of the current serving terminal;

[0092] Signals are transmitted to the terminal via the first satellite and the second satellite, respectively, so that the terminal can obtain and perform a synchronization process with the second satellite cell based on the time difference between the signals transmitted between the terminal and the base station via the first satellite and the second satellite, or the propagation delay difference between the signal and the first satellite and the second satellite.

[0093] In some implementations, signal transmission to the terminal is performed via the first satellite and the second satellite, respectively, so that the terminal obtains the time difference between the signals transmitted through the first satellite and the second satellite between the terminal and the base station, including:

[0094] The same downlink signal is transmitted to the terminal via the first satellite and the second satellite respectively, so that the terminal determines the reception time difference of the same downlink signal transmitted via the first satellite and the second satellite respectively;

[0095] Different downlink signals are transmitted to the terminal via the first satellite and the second satellite respectively, and the transmission time difference of the different downlink signals is notified to the terminal, so that the terminal will subtract the transmission time difference of the different downlink signals from the reception time difference of the different downlink signals transmitted via the first satellite and the second satellite respectively.

[0096] The terminal receives the same uplink signal transmitted through the first satellite and the second satellite respectively, detects the reception time difference of the same uplink signal, and sends the reception time difference to the terminal.

[0097] The terminal receives different uplink signals transmitted through the first satellite and the second satellite, respectively, detects the reception time difference of the different uplink signals, and sends the reception time difference to the terminal.

[0098] In some implementations, signal transmission is performed with the terminal via the first satellite and the second satellite, respectively, so that the terminal obtains the propagation delay difference of the signal between the terminal and the first satellite and the second satellite, including:

[0099] The terminal can determine the time difference between receiving the same downlink signal from the first satellite and the second satellite by sending the same downlink signal to the terminal via the first satellite and the second satellite.

[0100] Different downlink signals and their transmission times are sent to the terminal via the first satellite and the second satellite, so that the terminal determines the time difference between receiving the different downlink signals sent by the first satellite and the second satellite, and subtracts the transmission time difference between the first satellite and the second satellite from the time difference.

[0101] The terminal receives the same uplink signal sent by the terminal through the first satellite and the second satellite, and sends the first reception time of the same uplink signal to the terminal through the first satellite, and sends the second reception time of the same uplink signal to the terminal through the second satellite, so that the terminal calculates the difference between the first reception time and the second reception time.

[0102] The terminal receives different uplink signals sent by the first satellite and the second satellite, and sends the first reception time of the uplink signal to the terminal via the first satellite and the second reception time of the uplink signal to the terminal via the second satellite. The terminal calculates the difference between the first reception time and the second reception time, and subtracts the transmission time difference of the different uplink signals sent by the terminal from the difference.

[0103] In some embodiments, the processor is further configured to read a computer program from the memory and send one or a combination of the following information to the terminal:

[0104] The community signage remains unchanged;

[0105] The second satellite begins beam coverage of the area to which the terminal belongs;

[0106] Information on the time when the first satellite ceases beam coverage of the area to which the terminal belongs;

[0107] The time information or indication information for the terminal to begin the synchronization process with the second satellite cell;

[0108] Instructions to begin synchronizing with the second satellite cell;

[0109] The ephemeris information of the second satellite;

[0110] The common timing advance value information of the second satellite;

[0111] Downlink signal configuration information;

[0112] Uplink signal configuration information;

[0113] The base station transmits downlink signals via the first satellite and the second satellite respectively, using the transmission time difference information.

[0114] On the terminal side, another synchronization device in a satellite network provided in this application embodiment includes:

[0115] A determining unit is used to determine that the cell identifiers of the first satellite cell and the second satellite cell are the same; wherein, the first satellite cell is the cell of the current serving terminal;

[0116] The synchronization unit is used to perform a synchronization process between the terminal and the second satellite cell based on the time difference between the signals transmitted between the terminal and the base station through the first satellite and the second satellite, or based on the propagation delay difference between the signal and the first satellite and the second satellite.

[0117] On the network side, another synchronization device in a satellite network provided in this application embodiment includes:

[0118] The first unit is used to determine that the cell identifiers of the first satellite cell and the second satellite cell are the same; wherein, the first satellite cell is the cell of the current serving terminal;

[0119] The second unit is used to transmit signals to the terminal via the first satellite and the second satellite respectively, so that the terminal obtains and performs a synchronization process with the second satellite cell based on the time difference between the signals transmitted through the first satellite and the second satellite between the terminal and the base station, or the propagation delay difference between the signal and the first satellite and the second satellite.

[0120] Another embodiment of this application provides a processor-readable storage medium storing a computer program for causing the processor to perform any of the methods described above. Attached Figure Description

[0121] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0122] Figure 1 This is a schematic diagram of a quasi-surface fixed cell in the prior art;

[0123] Figure 2 This is a schematic diagram illustrating how gNB1 provides services to region A via a first satellite at time T1, and then continues to provide services to region A via a second satellite at time T2, as provided in this embodiment of the application.

[0124] Figure 3 This is a schematic diagram provided for an embodiment of the present application, showing that if there is a common coverage area A between a first satellite and a second satellite, for a period of time, both satellites are connected to gNB1 and provide the same cell coverage for area A;

[0125] Figure 4 A flowchart illustrating the synchronization method between the terminal and the network side in Embodiment 1 provided for the present application;

[0126] Figure 5 A flowchart illustrating the synchronization method between the terminal and the network side in Embodiment 2 provided for the present application;

[0127] Figure 6 A flowchart illustrating the synchronization method between the terminal and the network side in Embodiment 3 provided for the present application;

[0128] Figure 7 A schematic flowchart illustrating a synchronization method in a satellite network on the terminal side provided in an embodiment of this application;

[0129] Figure 8A schematic flowchart illustrating a synchronization method in a satellite network provided in an embodiment of this application;

[0130] Figure 9 A schematic diagram of the structure of a synchronization device in a satellite network on the terminal side provided in an embodiment of this application;

[0131] Figure 10 A schematic diagram of the structure of a synchronization device in a satellite network provided in an embodiment of this application;

[0132] Figure 11 A schematic diagram of the structure of a synchronization device in another satellite network on the terminal side provided in an embodiment of this application;

[0133] Figure 12 This is a schematic diagram of the structure of a synchronization device in another satellite network provided in an embodiment of this application. Detailed Implementation

[0134] In this embodiment of the invention, the term "and / or" describes the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following associated objects have an "or" relationship.

[0135] In the embodiments of this application, the term "multiple" refers to two or more, and other quantifiers are similar.

[0136] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0137] This application provides a synchronization method and apparatus in a satellite network, which provides an uplink and downlink synchronization update scheme for the terminal when the satellite providing beam coverage for the area to which the terminal belongs changes but the cell identifier does not change, in order to address the problem of uplink and downlink synchronization loss of the terminal caused by the change of satellite position.

[0138] The method and apparatus are based on the same concept of the application. Since the methods and apparatus solve problems in similar ways, the implementation of the apparatus and methods can refer to each other, and the repeated parts will not be described again.

[0139] The terms "first," "second," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0140] The following examples and embodiments are to be understood as illustrative only. While this specification may refer to "a," "an," or "some" examples or embodiments in several places, this does not mean that every such reference relates to the same example or embodiment, nor does it mean that the feature applies only to a single example or embodiment. Individual features of different embodiments may also be combined to provide other embodiments. Furthermore, terms such as "comprising" and "including" should be understood not to limit the described embodiments to consisting only of those features mentioned; such examples and embodiments may also include features, structures, units, modules, etc., not specifically mentioned.

[0141] The technical solutions provided in this application can be applied to various systems, especially 5G systems. For example, applicable systems include Global System for Mobile communication (GSM), Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (WCDMA) General Packet Radio Service (GPRS), Long Term Evolution (LTE), LTE Frequency Division Duplex (FDD), LTE Time Division Duplex (TDD), Long Term Evolution Advanced (LTE-A), Universal Mobile Telecommunication System (UMTS), Worldwide Interoperability for Microwave Access (WiMAX), and 5G New Radio (NR). All of these systems include terminal equipment and network equipment. The system may also include a core network component, such as the Evolved Packet System (EPS) or the 5G system (5GS).

[0142] The terminal devices involved in the embodiments of this application can be devices that provide voice and / or data connectivity to users, handheld devices with wireless connectivity, or other processing devices connected to a wireless modem. The names of the terminal devices may differ in different systems; for example, in a 5G system, a terminal device can be called User Equipment (UE). Wireless terminal devices can communicate with one or more core networks (CNs) via the RAN. Wireless terminal devices can be mobile terminal devices, such as mobile phones (or "cellular" phones) and computers with mobile terminal devices, for example, portable, pocket-sized, handheld, computer-embedded, or vehicle-mounted mobile devices that exchange voice and / or data with the radio access network. Examples include Personal Communication Service (PCS) phones, cordless phones, Session Initiated Protocol (SIP) phones, Wireless Local Loop (WLL) stations, Personal Digital Assistants (PDAs), and other devices. Wireless terminal equipment can also be referred to as a system, subscriber unit, subscriber station, mobile station, mobile station, remote station, access point, remote terminal, access terminal, user terminal, user agent, or user device, but is not limited to these terms in the embodiments of this application.

[0143] The network device involved in this application embodiment can be a base station, which may include multiple cells. Depending on the specific application, a base station may also be called an access point, or it may refer to a device in the access network that communicates with a wireless terminal device through one or more sectors on the air interface, or other names. The network device can be used to convert received air frames to and from Internet Protocol (IP) packets, and act as a router between the wireless terminal device and the rest of the access network, where the rest of the access network may include an Internet Protocol (IP) communication network. The network device can also coordinate the attribute management of the air interface. For example, the network equipment involved in the embodiments of this application can be a base transceiver station (BTS) in a Global System for Mobile Communications (GSM) or Code Division Multiple Access (CDMA), a node B in a bandwidth code division multiple access (WCDMA), an evolved Node B (eNB or e-NodeB) in a Long Term Evolution (LTE) system, a 5G base station in a 5G network architecture (next generation system), a Home evolved Node B (HeNB), a relay node, a femto, a pico, etc., and is not limited in the embodiments of this application. In some network structures, the network equipment may include centralized unit (CU) nodes and distributed unit (DU) nodes, and the centralized unit and distributed unit may also be geographically separated.

[0144] Network devices and terminal devices can each use one or more antennas for multiple-input multiple-output (MIMO) transmission. MIMO transmission can be single-user MIMO (SU-MIMO) or multiple-user MIMO (MU-MIMO). Depending on the configuration and number of antenna combinations, MIMO transmission can be 2D-MIMO, 3D-MIMO, FD-MIMO, or massive-MIMO, and can also be diversity transmission, precoding transmission, or beamforming transmission, etc.

[0145] The various embodiments of this application will now be described in detail with reference to the accompanying drawings. It should be noted that the order in which the embodiments are presented in this application represents only a chronological order and does not represent the superiority or inferiority of the technical solutions provided by the embodiments.

[0146] In earth-fixed scenarios, when a current cell is about to be moved due to satellite movement, and coverage is provided by another satellite, a large number of UEs need to hand over within a short period of time, leading to random access resource shortages and signaling storms. In actual network deployments, it can be designed so that for the same area, the coverage provided by the next satellite has the same Physical Cell Identifier (PCI) and frequency as the coverage provided by the previous satellite. In this case, although the satellite covering a certain area changes, the cell serving that area remains unchanged, theoretically eliminating the handover process. However, even if the PCI and frequency of the two cells do not change, the latency for UEs to access the gNB via the satellite changes due to the change in satellite position, requiring UEs to update uplink and downlink synchronization. Therefore, this application provides a terminal uplink and downlink synchronization update scheme, including how to trigger and complete the uplink and downlink synchronization update in the aforementioned scenario, and when to apply the new uplink and downlink synchronization information. The application of new uplink and downlink synchronization information, i.e., starting synchronization to the new satellite cell, actually involves applying the downlink reference time and TA value of the new satellite cell.

[0147] First, regarding uplink and downlink synchronization, the following is an introduction:

[0148] Downlink synchronization: The UE reads the Synchronization Signal / PBCH Block (SSB) and obtains information such as the system frame number contained in the Master Information Block (MIB) through decoding, thereby completing the downlink synchronization process. At this point, the UE can read downlink messages according to the system frame.

[0149] Uplink Synchronization: To ensure orthogonality of uplink transmission, the gNB requires that UE signals from different frequency domain resources within the same subframe arrive at the gNB at approximately the same time. Therefore, the UE needs to perform timing advance, meaning that the system frame from which the UE transmits uplink data must arrive a certain time earlier than the corresponding downlink frame. During initial uplink synchronization, the UE triggers a random access procedure. The gNB determines the Timing Advance (TA) value based on the received preamble and informs the UE of the timing advance amount through the random access response. Subsequently, when the UE is in connected state, the gNB adjusts the timing advance amount for the UE through the Timing Advance Command (TAC) in the Media Access Control Unit (MAC CE) to maintain uplink synchronization.

[0150] In the 3rd Generation Partnership Project (3GPP) Release 17 (R17) / Release 18 (R18) studies, satellites act as transparent relay units, connecting to ground base stations via gateway stations. The cell coverage provided by the satellites depends on the configuration of the base stations. For quasi-terrestrial fixed cells, through network architecture design and deployment, it is possible to achieve the effect of satellite changes covering a certain area without changes to the cells themselves; that is, the PCI and frequency of the cells serving that area remain unchanged. (See below.) Figure 2 As shown, at time T1, gNB1 provides services to area A through the first satellite. At time T2, gNB1 continues to provide services to area A through the second satellite. gNB1 can be configured so that the PCI (PCI1) and frequency (F1) of the cells in area A served by the first and second satellites are the same. Then, the UE in area A will think that the cell has not changed and does not need to perform handover, conditional handover or cell reselection.

[0151] In actual network deployments, it's possible that the second satellite begins providing coverage at the same time the first satellite ceases coverage of area A, or that the first and second satellites share coverage of area A for a period of time, meaning the second satellite begins coverage before the first satellite ceases service. See also Figure 3 If there is a shared coverage area A between the first satellite and the second satellite for a period of time, during which both satellites are connected to gNB1 and provide coverage for area A with the same PCI and frequency, then the first satellite cell and the second satellite cell are the same cell. The technical solution provided in this application embodiment achieves uplink and downlink synchronization when the UE accesses the cell through the second satellite in the above scenario.

[0152] In this embodiment, the terminal obtains the TA value TAsat2 of the second satellite access cell by using the time difference between the signals transmitted through the first satellite and the second satellite between the terminal and the base station (i.e., the signal transmission time difference from the terminal to the satellite and then to the base station) or the propagation delay difference between the signal between the terminal and the first satellite and the second satellite (i.e., the signal transmission time difference from the terminal to the satellite), and the TA value TAsat1 of the UE accessing the cell through the first satellite, and starts synchronizing to the second satellite cell as instructed.

[0153] In some implementations, the UE obtains the time difference of the signals transmitted through the first satellite and the second satellite in at least one of the following ways:

[0154] The time difference between the reception of the UE and the gNB of the same downlink signal transmitted through the first and second satellites respectively;

[0155] The UE receives the reception time difference of different downlink signals transmitted by the gNB through the first satellite and the second satellite, and subtracts the transmission time difference of the downlink signals (i.e., the difference between the time when the gNB transmits the downlink signal through the first satellite and the time when the gNB transmits another downlink signal through the second satellite).

[0156] The base station will send the detected UE to the UE through the time difference of receiving the same uplink signal transmitted by the first satellite and the second satellite respectively;

[0157] The base station sends the received time difference of the different uplink signals transmitted by the first satellite and the second satellite to the UE. The UE then subtracts the transmission time difference of the uplink signals (i.e., the difference between the time when the UE transmits the uplink signal through the first satellite and the time when the UE transmits another uplink signal through the second satellite) from this time.

[0158] In some implementations, the UE obtains the propagation delay difference (i.e., the propagation delay difference from the UE to the first and second satellites) of the service link between the UE and the first and second satellites (the service link refers to the transmission link between the UE and the satellites) in at least one of the following ways:

[0159] The time difference between when the UE receives the same downlink signal transmitted by the first and second satellites;

[0160] The time difference between the reception of the different downlink signals sent by the first satellite and the second satellite by the UE minus the time difference between the transmission of the downlink signals by the first satellite and the second satellite;

[0161] The first and second satellites will send the reception times of the same uplink signal sent by the UE to the UE respectively. The UE will calculate the difference between the time when the first satellite receives the uplink signal and the time when the second satellite receives the uplink signal.

[0162] The first and second satellites will send the reception times of the different uplink signals sent by the UE to the UE respectively. The UE will calculate the difference between the time when the first satellite receives the uplink signal and the time when the second satellite receives the different uplink signals, and make calculations based on this difference and the transmission time difference of the two different uplink signals.

[0163] In other words, in this embodiment of the application, if the satellite has a certain ability to transmit and detect signals, then the satellite can detect the uplink signal transmitted by the UE, or the satellite can directly transmit the downlink signal to the UE.

[0164] This allows us to calculate the service link delay difference between the UE and the two satellites. The delay difference in the feeder link between the two satellites and the base station can be compensated by the network or calculated using parameters such as the common TA. In this case, the gNB can provide uplink and downlink signal configuration information to the satellites.

[0165] In some implementations, the gNB sends at least one of the following information to the first and second satellites:

[0166] Downlink signal configuration information: time, frequency, period, index, etc.;

[0167] Uplink signal configuration information: time, frequency, period, index, etc.;

[0168] For example, the downlink signal could be:

[0169] Cell Defined SSB (CD-SSB);

[0170] Non-Cell Defined Synchronization Signal Block (NCD-SSB);

[0171] Other downlink signals include, for example, Channel State Information-Reference Signal (CSI-RS) and Positioning Reference Signal (PRS).

[0172] For example, the uplink signal can be:

[0173] Uplink data or signaling in normal business processes;

[0174] Configure uplink signals with dedicated time and frequency resources, such as uplink sounding reference signals (SRS).

[0175] In some implementations, the TA value for the UE to access the cell via the second satellite can be:

[0176] With reference to the downlink frame of the second satellite, the UE accesses the cell's TA via the second satellite;

[0177] With reference to the downlink frame of the first satellite, the UE accesses the cell's TA via the second satellite;

[0178] In some implementations, the network provides the UE with at least one of the following:

[0179] The community signage remains unchanged;

[0180] The indication of when the second satellite begins coverage or the Coordinated Universal Time (UTC) time at which coverage begins;

[0181] The time when the first satellite ceases coverage;

[0182] The time or indication at which the UE begins uplink and downlink synchronization via the second satellite access cell;

[0183] The time at which synchronization with the second satellite cell begins, or an indication of how long after synchronization with the second satellite cell will begin.

[0184] Ephemeris information of the second satellite;

[0185] Common TA related parameters of the second satellite;

[0186] The relevant configuration information of the downlink signal includes: time, frequency, period, index, etc.

[0187] The relevant configuration information of the uplink signal includes: time, frequency, period, index, and effective time.

[0188] The transmission time difference is calculated by transmitting different downlink signals via the first satellite and the second satellite, respectively. This transmission time difference is the difference between the time the gNB transmits the downlink signal via the first satellite and the time the gNB transmits the downlink signal via the second satellite. If the difference is 0, it indicates that the downlink signals are transmitted simultaneously, and therefore the downlink signals transmitted by the gNB via the first satellite and the downlink signals transmitted via the second satellite are considered to be the same downlink signal; otherwise, they are considered to be different downlink signals.

[0189] In some implementations, after the terminal obtains one or more of the above information, it is determined that the terminal will face uplink and downlink synchronization failure, and needs to obtain new uplink and downlink synchronization in advance, and start the application according to the instructions (i.e. start synchronizing to the new satellite cell).

[0190] In some implementations, the network provides the above information to the UE in one or more of the following ways:

[0191] Broadcasting, for example, can include one or more of the above information in a system message and broadcast it to all UEs;

[0192] Specialized signaling, such as Radio Resource Control (RRC) reconfiguration messages;

[0193] Pre-configuration: When using this method, you can also specify the effective time of the pre-configuration message, or activate it via signaling.

[0194] In some implementations, the time at which the terminal begins synchronizing with the second satellite cell can be:

[0195] The network configures a time to start synchronizing to the second satellite cell. This time may be the same for all UEs, that is, all UEs' connections switch from the first satellite to the second satellite at the same time. This time may also be different for each UE. Each UE starts synchronizing to the second satellite cell according to the time it receives from the network configuration.

[0196] After the UE obtains the updated TA value, it immediately begins to synchronize with the second satellite cell;

[0197] The network sends an instruction to the UE to begin synchronizing with the second satellite cell. This instruction can be sent to the UE via dedicated signaling per UE or broadcast to all UEs.

[0198] Example 1: Synchronization is calculated using downlink signals.

[0199] See Figure 4 The specific synchronization process includes:

[0200] S401. The UE accesses cell A through the first satellite for uplink and downlink transmission. Starting from time t1, the second satellite begins to provide coverage. The second satellite begins to broadcast the synchronization signal block (SSB) according to the configuration.

[0201] S402, gNB sends a message to UE through the first satellite to inform UE that the second satellite has started to provide coverage. At the same time, it can provide the ephemeris of the second satellite, common TA, the time when synchronization with the second satellite cell begins, and downlink signal related information used for synchronization (e.g., gNB broadcasts the time and frequency location of SSB through the second satellite).

[0202] S403. The UE reads the synchronization signal block SSB broadcast by the second satellite and completes downlink synchronization for accessing cell A via the second satellite, but this downlink synchronization is not applied at this time. The UE receives the synchronization signal block forwarded by the first and second satellites at times Tssb1 and Tssb2, respectively, and obtains the reception time difference ΔTssb, where ΔTssb = Tssb2 - Tssb1. If the base station transmits the synchronization signal block via the first and second satellites at times Ts1 and Ts2, respectively, and there is a transmission time difference ΔToffset = Ts2 - Ts1, then ΔToffset must be removed when calculating the TA value TAsat2 for accessing the cell via the second satellite.

[0203] Based on the above information, the UE calculates the TA value TAsat2 of the second satellite to access the cell through the TA value TAsat1 of the first satellite access cell.

[0204] For example, TAsat2 = TAsat1 + (ΔTssb - ΔToffset) * 2.

[0205] S404. The UE begins synchronizing with the second satellite cell based on the start time received in step S402. This start time can be per cell or per UE. For example, the network can set the start time for all UEs within a cell to be the moment the first satellite stops providing coverage. When this moment arrives, all UEs simultaneously begin synchronizing with the second satellite cell and perform uplink and downlink transmissions via the second satellite. Alternatively, the network can set the start time for each UE to synchronize with the second satellite cell to be different.

[0206] Example 2: Calculate synchronization using uplink signals.

[0207] See Figure 5 The specific synchronization process includes:

[0208] S501, the UE accesses cell A through the first satellite for uplink and downlink transmission. Starting from time t1, the second satellite begins to provide coverage for cell A and listens for uplink messages sent by the UE.

[0209] S502 and gNB calculate the times when they receive the uplink signal from the UE via the first and second satellites, respectively, as Tue1 and Tue2, and calculate the reception delay difference as ΔT. UL =Tue2-Tue1.

[0210] If the UE transmits uplink signals via the first satellite and the second satellite at times Ts1 and Ts2 respectively, and there is a transmission time difference ΔToffset = Ts2 - Ts1, then ΔToffset should be removed when calculating the TA adjustment amount.

[0211] S503 and gNB transmit the acquired delay difference ΔT to the UE via the first satellite. UL ;

[0212] S504, The UE adjusts ΔT based on the original timing advance value TAsat1. UL -ΔToffset yields the updated timing advance value TAsat2, for example, TAsat2 = TAsat1 + ΔT UL -ΔToffset.

[0213] If there is no transmission time difference when the UE sends the uplink signal, then ΔToffset is 0, for example, TAsat2=TAsat1+ΔT UL .

[0214] At this time, the UE's TA is based on the downlink frame of the first satellite and the uplink timing advance of the second satellite.

[0215] S505. After the first satellite stops providing coverage, the gNB sends an SSB through the second satellite. The UE performs downlink synchronization based on the received SSB and readjusts the TA again with reference to the new downlink frame (i.e., the downlink frame sent by the base station through the second satellite). The adjustment amount is the time difference ΔTssb between the downlink frames of the first and second satellites. At this point, the UE has completed the uplink and downlink synchronization of the second satellite.

[0216] In other words, in this embodiment, the UE obtains the delay difference ΔT UL Immediately afterwards, the TA is adjusted, i.e., TAsat2 is determined. However, the UE does not need to know that this TA is the uplink synchronization adjustment value of the cell accessed through the second satellite. At this time, uplink data between the UE and gNB is transmitted transparently through the second satellite, and downlink data is transmitted transparently through the first satellite. When the first satellite stops service and the second satellite begins broadcasting the synchronization signal block, the UE re-synchronizes downlink and adjusts the TA value according to the time difference between the previous and subsequent downlink synchronizations.

[0217] It should be noted that regarding the statement in step S504 that "at this time, the UE's TA is based on the downlink frame of the first satellite and the uplink timing advance of the second satellite," this means that before this step, the UE cannot read the SSB of the second satellite and has not yet performed downlink synchronization through the second satellite to access the cell. Therefore, downlink synchronization can only be performed based on the downlink frame of the first satellite. Furthermore, in step S505, when the gNB sends the SSB to the terminal through the second satellite, the terminal adjusts the TA again with reference to the new downlink frame (the downlink frame transparently transmitted by the second satellite). That is, TAsat2' is obtained from TAsat2 calculated in step S504. The specific adjustment amount is the time difference ΔT between the downlink frames transparently transmitted by the first and second satellites, for example, TAsat2' = TAsat2 - ΔT.

[0218] Example 3:

[0219] Unlike step S504 in the above embodiments, in this embodiment, after the UE obtains the adjustment amount of TA, it does not apply it immediately (i.e., it does not synchronize with the second satellite cell for the time being), but instead starts synchronizing with the second satellite cell at a certain configured time. This time point can be the time when the first satellite stops service, or a time configured for the UE by the network. This time point can be configured separately for each UE, or it can be configured to be the same time for all UEs.

[0220] The specific synchronization process in this embodiment is similar to that in Embodiment 2. (See [link to Embodiment 2]) Figure 6Steps S601 to S605 are the same as steps S501 to S505 in the above embodiment 2, and will not be described in detail again. The difference is that in this embodiment, after step S604, the updated TA is not applied immediately, but the uplink and downlink data transmission is continued using the first satellite. After step S605, synchronization with the second satellite cell is started, and the uplink and downlink data and signaling transmission is carried out using the second satellite.

[0221] As can be seen from the above solutions, on the terminal side, see... Figure 7 This application provides a synchronization method in a satellite network, comprising:

[0222] S101. Determine that the cell identifiers (such as PCI or Cell Global Identity, CGI, etc.) of the first and second satellite cells of the current serving terminal are the same.

[0223] For example:

[0224] The first satellite cell refers to the cell through which the UE is accessing the network via the first satellite;

[0225] The second satellite cell refers to the cell through which the UE will access the network via a second satellite;

[0226] If the cell identifiers of the first and second satellite cells are the same or unchanged, it means that both satellites are connected to the same base station, which provides coverage for the same area and / or the same cell identifier and / or the same frequency point through the two satellites. The first and second satellite cells may have overlapping coverage periods; that is, the second satellite cell begins coverage before the first satellite cell ceases service. Alternatively, the first and second satellite cells may seamlessly succeed each other, with the second satellite cell starting service as soon as the first satellite cell leaves.

[0227] S102. Based on the time difference between the signals transmitted between the terminal and the base station through the first satellite and the second satellite, or based on the propagation delay difference between the terminal and the first satellite and the second satellite, perform the synchronization process between the terminal and the second satellite cell.

[0228] In some implementations, the time difference between the terminal and the base station via the signals transmitted through the first satellite and the second satellite is determined by one or more of the following methods:

[0229] The terminal determines the reception time difference when it receives the same downlink signal transmitted by the base station through the first satellite and the second satellite, respectively.

[0230] The terminal subtracts the transmission time difference of the base station from the reception time difference of the different downlink signals received by the terminal from the base station through the first satellite and the second satellite respectively.

[0231] The terminal receives the reception time difference of the same uplink signal transmitted by the terminal through the first satellite and the second satellite, respectively, as detected by the base station.

[0232] The terminal receives the reception time difference of the different uplink signals transmitted by the terminal through the first satellite and the second satellite, respectively, detected by the base station, and subtracts the transmission time difference of the different uplink signals from the reception time difference.

[0233] In some implementations, the propagation delay difference of the signal between the terminal and the first and second satellites is determined by one or more of the following methods:

[0234] The terminal determines the time difference between receiving the same downlink signal sent by the first satellite and the second satellite;

[0235] The terminal determines the time difference between receiving different downlink signals sent by the first satellite and the second satellite, and subtracts the transmission time difference between the first satellite and the second satellite from the time difference.

[0236] The terminal receives a first reception time when the first satellite detects the uplink signal sent by the terminal, and a second reception time when the second satellite detects the same uplink signal sent by the terminal, and calculates the difference between the first reception time and the second reception time.

[0237] The terminal receives a first reception time when the first satellite detects an uplink signal sent by the terminal, and a second reception time when the second satellite detects different uplink signals sent by the terminal. The terminal calculates the difference between the first reception time and the second reception time, and subtracts the transmission time difference of the different uplink signals sent by the terminal from the difference.

[0238] In some implementations, prior to performing the synchronization process with the second satellite cell, the method further includes acquiring one or a combination of the following information:

[0239] The community signage remains unchanged;

[0240] The second satellite begins beam coverage of the area to which the terminal belongs;

[0241] Information on the time when the first satellite ceases beam coverage of the area to which the terminal belongs;

[0242] The time information or indication information for the terminal to begin the synchronization process with the second satellite cell;

[0243] Indication information to start synchronization with the second satellite cell, such as the time to start synchronization with the second satellite cell or an indication of how long after synchronization with the second satellite cell will begin;

[0244] The ephemeris information of the second satellite;

[0245] The common timing advance information (common TA related parameters) of the second satellite;

[0246] Configuration information for downlink signals, such as transmission time, frequency, period, and index of downlink signals;

[0247] Uplink signal configuration information, such as uplink signal transmission time, frequency, period, index, etc.;

[0248] The base station transmits downlink signals via the first satellite and the second satellite respectively, using the transmission time difference information.

[0249] In some implementations, when one or a combination of the information is received, it is assumed that the cell identifiers of the first satellite cell and the second satellite cell are the same, that is, it is determined that the synchronization process between the terminal and the second satellite cell needs to be performed.

[0250] In some embodiments, the method further includes:

[0251] According to the network-side configuration, synchronization with the second satellite cell begins; for example, it can be a specific time, and this time may be the same for all UEs, that is, all UEs' connections switch from the first satellite to the second satellite at the same time; this time may also be different for each UE, and each UE executes new uplink and downlink synchronization parameters according to the time it receives;

[0252] Alternatively, after the terminal obtains the updated timing advance value, it immediately begins to synchronize with the second satellite cell;

[0253] Alternatively, upon receiving a network-side instruction, synchronization with the second satellite cell can begin. This network-side instruction can be sent to each UE via dedicated signaling or broadcast to all UEs.

[0254] In some implementations, during the synchronization process between the terminal and the second satellite, uplink and downlink synchronization between the terminal and the first satellite cell is maintained, thereby ensuring the continuity of the terminal's services. In scenarios where two satellites do not provide simultaneous coverage, the UE needs to pause data transmission during the handover process between different satellite cells until the UE successfully switches to the new satellite cell. However, in the technical solution provided in this application embodiment, the UE can maintain data service transmission without interruption.

[0255] Additionally, it should be noted that in this embodiment, during the synchronization process between the UE and the second satellite cell, the transmission of data and signaling between the UE and the base station can be simultaneously transmitted through the first and second satellites, or only through one of them; alternatively, normal data and signaling transmission can be performed through one of the satellites (the first satellite), while monitoring the signal transmitted through the other satellite (the second satellite). If the monitored signal is successfully decoded, the aforementioned transmission delay difference (i.e., the time difference between the signal transmitted between the terminal and the base station through the first and second satellites as described in step S102, or the propagation delay difference of the signal between the terminal and the first and second satellites) is obtained. If decoding fails, monitoring continues until successful decoding is achieved, and the corresponding transmission delay difference is obtained. This application does not limit the specific implementation method.

[0256] Accordingly, on the network side, see Figure 8 The synchronization method in a satellite network provided in this application includes:

[0257] S201. Determine that the cell identifiers (e.g., PCI or Cell Global Identity, CGI, etc.) of the first and second satellite cells of the current serving terminal are the same.

[0258] S202. Signal transmission is performed between the terminal and the first satellite and the second satellite, respectively, so that the terminal obtains and performs a synchronization process with the second satellite cell based on the time difference between the signal transmitted through the first satellite and the second satellite between the terminal and the base station, or the propagation delay difference between the signal between the terminal and the first satellite and the second satellite.

[0259] In some implementations, signal transmission to the terminal is performed via the first satellite and the second satellite, respectively, so that the terminal obtains the time difference between the signals transmitted through the first satellite and the second satellite between the terminal and the base station, including:

[0260] The same downlink signal is transmitted to the terminal via the first satellite and the second satellite respectively, so that the terminal determines the reception time difference of the same downlink signal transmitted via the first satellite and the second satellite respectively;

[0261] Different downlink signals are transmitted to the terminal via the first satellite and the second satellite respectively, and the transmission time difference of the different downlink signals is notified to the terminal, so that the terminal will subtract the transmission time difference of the different downlink signals from the reception time difference of the different downlink signals transmitted via the first satellite and the second satellite respectively.

[0262] The terminal receives the same uplink signal transmitted through the first satellite and the second satellite respectively, detects the reception time difference of the same uplink signal, and sends the reception time difference to the terminal.

[0263] The terminal receives different uplink signals transmitted through the first satellite and the second satellite, respectively, detects the reception time difference of the different uplink signals, and sends the reception time difference to the terminal.

[0264] In some implementations, signal transmission is performed with the terminal via the first satellite and the second satellite, respectively, so that the terminal obtains the propagation delay difference of the signal between the terminal and the first satellite and the second satellite, including:

[0265] The terminal can determine the time difference between receiving the same downlink signal from the first satellite and the second satellite by sending the same downlink signal to the terminal via the first satellite and the second satellite.

[0266] Different downlink signals and their transmission times are sent to the terminal via the first satellite and the second satellite, so that the terminal determines the time difference between receiving the different downlink signals sent by the first satellite and the second satellite, and subtracts the transmission time difference between the first satellite and the second satellite from the time difference.

[0267] The terminal receives the same uplink signal sent by the terminal through the first satellite and the second satellite, and sends the first reception time of the same uplink signal to the terminal through the first satellite, and sends the second reception time of the same uplink signal to the terminal through the second satellite, so that the terminal calculates the difference between the first reception time and the second reception time.

[0268] The terminal receives different uplink signals sent by the first satellite and the second satellite, and sends the first reception time of the uplink signal to the terminal via the first satellite and the second reception time of the uplink signal to the terminal via the second satellite. The terminal calculates the difference between the first reception time and the second reception time, and subtracts the transmission time difference of the different uplink signals sent by the terminal from the difference.

[0269] In some embodiments, the method further includes sending one or a combination of the following information to the terminal:

[0270] The community signage remains unchanged;

[0271] The second satellite begins beam coverage of the area to which the terminal belongs;

[0272] Information on the time when the first satellite ceases beam coverage of the area to which the terminal belongs;

[0273] The time information or indication information for the terminal to begin the synchronization process with the second satellite cell;

[0274] Instructions to begin synchronizing with the second satellite cell;

[0275] The ephemeris information of the second satellite;

[0276] The common timing advance value information of the second satellite;

[0277] Downlink signal configuration information;

[0278] Uplink signal configuration information;

[0279] The base station transmits downlink signals via the first satellite and the second satellite respectively, using the transmission time difference information.

[0280] The following are some examples of specific embodiments.

[0281] Example 4:

[0282] Reference Figure 4 The UE is currently connected to cell A and performs uplink and downlink signaling and data transmission through sat1 (the first satellite). Starting from time t1, sat2 begins to provide coverage, and sat2 (the second satellite) broadcasts NCD-SSB according to the configuration.

[0283] The gNB sends a dedicated signaling message to the UE via sat1. This dedicated signaling message includes: a 1-bit indication that the cell identifier remains unchanged, a 1-bit indication that sat2 will begin providing coverage, and the time T for starting synchronization with sat2 cell. update The time-frequency information of the non-cell-defined synchronization signal block transmitted through sat2 is transmitted through the downlink signal transmission time difference ΔToffset transmitted through sat2 and sat1 respectively.

[0284] After receiving an indication that the cell identifier remains unchanged, the UE believes it will face uplink / downlink synchronization issues and needs to obtain new uplink / downlink synchronization in advance, and then... updateApplication timing. The UE first reads the NCD-SSB broadcast by sat2 to complete downlink synchronization for accessing cell A via sat2, but this is not applied at this time. The UE receives the reception time Tssb1 of the SSB forwarded via sat1 and the reception time Tssb2 of the corresponding NCD-SSB forwarded via sat2, and calculates ΔTssb = Tssb2 - Tssb1. The TA value of the UE currently accessing the cell via sat1 is TAsat1. The TA value TAsat2 of the UE accessing the cell via sat2 can be calculated using the formula TAsat2 = TAsat1 + (ΔTssb - ΔToffset) * 2, with TAsat2 referencing the downlink frame of sat2.

[0285] The UE starts synchronizing with the Sat2 cell from the time received. update Synchronization with the sat2 cell begins, and uplink and downlink data and signaling transmissions begin through sat2.

[0286] Example 5:

[0287] Reference Figure 4 The UE is currently connected to cell A and performs uplink and downlink signaling and data transmission through sat1. Starting from time t1, sat2 begins to provide coverage, and sat2 broadcasts SSB according to the configuration.

[0288] The gNB broadcasts via sat1: sat2 will begin providing the covered UTC time Tc and duration D, where D indicates how long after Tc it will begin synchronizing with the sat2 cell;

[0289] Based on the received information, the UE anticipates uplink and downlink synchronization issues at time Tc, requiring it to acquire new uplink and downlink synchronization in advance and apply it at time Tc+D. The UE first reads the SSB broadcast by sat2 to complete downlink synchronization for accessing cell A via sat2, but does not apply it at this time. The UE receives and calculates the times of the same SSB forwarded via sat1 and sat2 as Tssb1 and Tssb2, respectively, and calculates ΔTssb = Tssb2 - Tssb1. The TA value for the UE currently accessing the cell via sat1 is TAsat1. The TA value for the UE accessing the cell via sat2 can be calculated using the formula TAsat2 = TAsat1 + ΔTssb * 2, where TAsat2 is referenced to the downlink frame of sat2.

[0290] The UE starts synchronizing with the sat2 cell from Tc+D and begins uplink and downlink data and signaling transmission through sat2.

[0291] Example 6:

[0292] Reference Figure 5The UE is currently connected to cell A and transmits uplink and downlink signaling and data through sat1. Starting from time t1, sat2 begins to provide coverage and begins to receive uplink signals sent by the UE.

[0293] When the gNB detects the same uplink signal forwarded via sat1 and sat2 respectively, the reception times are T UL1 and T UL2 The receiving time difference ΔT is calculated. UL =T UL2 –T UL1 ;

[0294] gNB will calculate the received time difference ΔT UL Send to UE;

[0295] The UE uses the TA value TAsat1, which is currently used to access the cell via sat1, and calculates TAsat2 using the formula TAsat2 = TAsat1 + ΔT. UL The TA value TAsat2 for the UE accessing the cell via sat2 can be calculated, with TAsat2 referencing the downlink frame of sat1. After this, uplink data sent by the UE is forwarded to the gNB via sat2, and downlink data is sent to the UE via sat1; the UE is unaware of this process.

[0296] After Sat1 ceases coverage, the gNB begins broadcasting the SSB via Sat2. The UE performs downlink synchronization and adjusts the TA according to the difference ΔT before and after the downlink frame update. The adjusted TA is referenced to the downlink frame of Sat2. After this, the UE performs uplink and downlink data transmission and signaling transmission via Sat2.

[0297] Example 7:

[0298] Reference Figure 5 The UE is currently connected to cell A and performs uplink and downlink signaling and data transmission through sat1 transparent transmission. Coverage is provided from time t1 to sat2.

[0299] The gNB indicates the time and frequency resources of the downlink signals to be transmitted to sat1 and sat2, and sat1 and sat2 transmit downlink PRS signals according to the gNB's instructions.

[0300] The gNB indicates to the UE the time-frequency position of the downlink signal that needs to be monitored, and informs the UE of the transmission time difference ΔToffset of the downlink signal transmitted through sat2 and sat1 respectively, and optionally informs the UE of the method of TA adjustment based on the obtained information;

[0301] The UE detects that the reception times of the downlink signals transmitted through sat1 and sat2 are T respectively. DL1 and TDL2 The receiving time difference ΔT is calculated. DL =T DL2 –T DL1 ;

[0302] The UE uses the TA value TAsat1, which is currently used to access the cell via sat1, and calculates TAsat2 using the formula TAsat2 = TAsat1 + ΔT. DL -ΔToffset can be used to calculate the TA value TAsat2 for the UE to access the cell via sat2. TAsat2 is referenced to the downlink frame of sat1. After this, uplink data sent by the UE is forwarded to the gNB via sat2, and downlink data is sent to the UE via sat1. The UE is unaware of this process.

[0303] After SAT1 stops providing coverage, the gNB begins broadcasting the SSB via SAT2. The UE performs downlink synchronization updates and adjusts the TA according to the difference ΔT between the downlink frame before and after the update. The adjusted TA is referenced to the downlink frame of SAT2. After this, the UE performs uplink and downlink data transmission and signaling transmission via SAT2.

[0304] In summary, the technical solution provided in this application addresses the earth-fixed scenario where the satellite beam changes while the cell's PCI and frequency remain constant. Due to the change in satellite position, the UE's access latency to the gNB via satellite changes, requiring the UE to update uplink and downlink synchronization. In this scenario, there is still no effective solution for how to complete the uplink and downlink synchronization update and when to apply the new synchronization. This application considers utilizing the time difference between the same or different signals relayed by two satellites to calculate and perform the uplink and downlink synchronization update. Without requiring handover or obtaining a TA through random access, it smoothly completes the UE's transition from accessing the cell via two satellites, reducing the number of signaling messages and avoiding service interruptions.

[0305] The following describes the device or apparatus provided in the embodiments of this application, and the explanations or examples of the same or corresponding technical features as those described in the above methods will not be repeated hereafter.

[0306] On the terminal side, see Figure 9 This application provides a synchronization device in a satellite network, comprising:

[0307] Processor 600 is used to read the program from memory 620 and execute the following procedures:

[0308] It is determined that the cell identifiers of the first satellite cell and the second satellite cell are the same; wherein, the first satellite cell is the cell of the current serving terminal;

[0309] Based on the time difference between the signals transmitted between the terminal and the base station via the first satellite and the second satellite, or based on the propagation delay difference between the terminal and the first satellite and the second satellite, the synchronization process between the terminal and the second satellite cell is performed.

[0310] In some implementations, the time difference between the terminal and the base station via the signals transmitted through the first satellite and the second satellite is determined by one or more of the following methods:

[0311] The terminal determines the reception time difference when it receives the same downlink signal transmitted by the base station through the first satellite and the second satellite, respectively.

[0312] The terminal subtracts the transmission time difference of the base station from the reception time difference of the different downlink signals received by the terminal from the base station through the first satellite and the second satellite respectively.

[0313] The terminal receives the reception time difference of the same uplink signal transmitted by the terminal through the first satellite and the second satellite, respectively, as detected by the base station.

[0314] The terminal receives the reception time difference of the different uplink signals transmitted by the terminal through the first satellite and the second satellite, respectively, detected by the base station, and subtracts the transmission time difference of the different uplink signals from the reception time difference.

[0315] In some implementations, the propagation delay difference of the signal between the terminal and the first and second satellites is determined by one or more of the following methods:

[0316] The terminal determines the time difference between receiving the same downlink signal sent by the first satellite and the second satellite;

[0317] The terminal determines the time difference between receiving different downlink signals sent by the first satellite and the second satellite, and subtracts the transmission time difference between the first satellite and the second satellite from the time difference.

[0318] The terminal receives a first reception time when the first satellite detects the uplink signal sent by the terminal, and a second reception time when the second satellite detects the same uplink signal sent by the terminal, and calculates the difference between the first reception time and the second reception time.

[0319] The terminal receives a first reception time when the first satellite detects an uplink signal sent by the terminal, and a second reception time when the second satellite detects different uplink signals sent by the terminal. The terminal calculates the difference between the first reception time and the second reception time, and subtracts the transmission time difference of the different uplink signals sent by the terminal from the difference.

[0320] In some implementations, prior to performing the synchronization process with the second satellite cell, the processor is further configured to read the computer program in the memory and obtain one or a combination of the following information:

[0321] The community signage remains unchanged;

[0322] The second satellite begins beam coverage of the area to which the terminal belongs;

[0323] Information on the time when the first satellite ceases beam coverage of the area to which the terminal belongs;

[0324] The time information or indication information for the terminal to begin the synchronization process with the second satellite cell;

[0325] Instructions to begin synchronizing with the second satellite cell;

[0326] The ephemeris information of the second satellite;

[0327] The common timing advance value information of the second satellite;

[0328] Downlink signal configuration information;

[0329] Uplink signal configuration information;

[0330] The base station transmits downlink signals via the first satellite and the second satellite respectively, using the transmission time difference information.

[0331] In some implementations, when one or a combination of the information is received, the processor 600 determines that a synchronization process between the terminal and the second satellite cell needs to be performed.

[0332] In some embodiments, the processor 600 is further configured to read a computer program from the memory 620 and perform the following operations:

[0333] According to the network configuration, synchronization with the second satellite cell begins;

[0334] Alternatively, after the terminal obtains the updated timing advance value, it immediately begins to synchronize with the second satellite cell;

[0335] Alternatively, upon receiving an instruction from the network side, synchronization with the second satellite cell can begin.

[0336] Transceiver 610 is used to receive and send data under the control of processor 600.

[0337] Among them, Figure 9 In this context, the bus architecture can include any number of interconnected buses and bridges, specifically linking various circuits of one or more processors represented by processor 600 and memory represented by memory 620 together. The bus architecture can also link various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. The bus interface provides an interface. The transceiver 610 can be multiple components, including transmitters and receivers, providing a unit for communicating with various other devices over a transmission medium, including wireless channels, wired channels, optical fibers, etc. For different user equipment, the user interface 630 can also be an interface capable of connecting external or internal devices, including but not limited to keypads, displays, speakers, microphones, joysticks, etc.

[0338] The processor 600 is responsible for managing the bus architecture and general processing, while the memory 620 can store the data used by the processor 600 when performing operations.

[0339] In some implementations, the processor 600 may be a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a CPLD (Complex Programmable Logic Device), and the processor may also employ a multi-core architecture.

[0340] The processor executes any of the methods described in the embodiments of this application by invoking a computer program stored in memory, according to the obtained executable instructions. The processor and memory may also be physically separated.

[0341] On the network side, such as the base station side, see [link to relevant documentation]. Figure 10 This application provides a synchronization device (e.g., a base station itself) in a satellite network, comprising:

[0342] Processor 500 is used to read the program from memory 520 and execute the following procedures:

[0343] It is determined that the cell identifiers of the first satellite cell and the second satellite cell are the same; wherein, the first satellite cell is the cell of the current serving terminal;

[0344] Signals are transmitted to the terminal via the first satellite and the second satellite, respectively, so that the terminal can obtain and perform a synchronization process with the second satellite cell based on the time difference between the signals transmitted between the terminal and the base station via the first satellite and the second satellite, or the propagation delay difference between the signal and the first satellite and the second satellite.

[0345] In some implementations, signal transmission to the terminal is performed via the first satellite and the second satellite, respectively, so that the terminal obtains the time difference between the signals transmitted through the first satellite and the second satellite between the terminal and the base station, including:

[0346] The same downlink signal is transmitted to the terminal via the first satellite and the second satellite respectively, so that the terminal determines the reception time difference of the same downlink signal transmitted via the first satellite and the second satellite respectively;

[0347] Different downlink signals are transmitted to the terminal via the first satellite and the second satellite respectively, and the transmission time difference of the different downlink signals is notified to the terminal, so that the terminal will subtract the transmission time difference of the different downlink signals from the reception time difference of the different downlink signals transmitted via the first satellite and the second satellite respectively.

[0348] The terminal receives the same uplink signal transmitted through the first satellite and the second satellite respectively, detects the reception time difference of the same uplink signal, and sends the reception time difference to the terminal.

[0349] The terminal receives different uplink signals transmitted through the first satellite and the second satellite, respectively, detects the reception time difference of the different uplink signals, and sends the reception time difference to the terminal.

[0350] In some implementations, signal transmission is performed with the terminal via the first satellite and the second satellite, respectively, so that the terminal obtains the propagation delay difference of the signal between the terminal and the first satellite and the second satellite, including:

[0351] The terminal can determine the time difference between receiving the same downlink signal from the first satellite and the second satellite by sending the same downlink signal to the terminal via the first satellite and the second satellite.

[0352] Different downlink signals and their transmission times are sent to the terminal via the first satellite and the second satellite, so that the terminal determines the time difference between receiving the different downlink signals sent by the first satellite and the second satellite, and subtracts the transmission time difference between the first satellite and the second satellite from the time difference.

[0353] The terminal receives the same uplink signal sent by the terminal through the first satellite and the second satellite, and sends the first reception time of the same uplink signal to the terminal through the first satellite, and sends the second reception time of the same uplink signal to the terminal through the second satellite, so that the terminal calculates the difference between the first reception time and the second reception time.

[0354] The terminal receives different uplink signals sent by the first satellite and the second satellite, and sends the first reception time of the uplink signal to the terminal via the first satellite and the second reception time of the uplink signal to the terminal via the second satellite. The terminal calculates the difference between the first reception time and the second reception time, and subtracts the transmission time difference of the different uplink signals sent by the terminal from the difference.

[0355] In some embodiments, the processor 500 is further configured to read a computer program from the memory 520 and send one or a combination of the following information to the terminal:

[0356] The community signage remains unchanged;

[0357] The second satellite begins beam coverage of the area to which the terminal belongs;

[0358] Information on the time when the first satellite ceases beam coverage of the area to which the terminal belongs;

[0359] The time information or indication information for the terminal to begin the synchronization process with the second satellite cell;

[0360] Instructions to begin synchronizing with the second satellite cell;

[0361] The ephemeris information of the second satellite;

[0362] The common timing advance value information of the second satellite;

[0363] Downlink signal configuration information;

[0364] Uplink signal configuration information;

[0365] The base station transmits downlink signals via the first satellite and the second satellite respectively, using the transmission time difference information.

[0366] Transceiver 510 is used to receive and send data under the control of processor 500.

[0367] Among them, Figure 10 In this context, the bus architecture can include any number of interconnected buses and bridges, specifically linking various circuits together, represented by one or more processors (processor 500) and memory (memory 520). The bus architecture can also link various other circuits such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. The bus interface provides an interface. The transceiver 510 can be multiple elements, including transmitters and receivers, providing a unit for communicating with various other devices over transmission media, including wireless channels, wired channels, optical fibers, etc. The processor 500 is responsible for managing the bus architecture and general processing, and the memory 520 can store data used by the processor 500 during operation.

[0368] The processor 500 can be a central processing unit (CPU), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a complex programmable logic device (CPLD). The processor can also adopt a multi-core architecture.

[0369] It should be noted that the apparatus provided in this embodiment of the invention can implement all the method steps implemented in the above method embodiment and can achieve the same technical effect. Therefore, the parts and beneficial effects that are the same as those in the method embodiment will not be described in detail here.

[0370] On the terminal side, see Figure 11 Another synchronization device in a satellite network provided in this application embodiment includes:

[0371] The determining unit 111 is used to determine that the cell identifiers of the first satellite cell and the second satellite cell are the same; wherein, the first satellite cell is the cell of the current serving terminal;

[0372] Synchronization unit 112 is used to perform a synchronization process between the terminal and the second satellite cell based on the time difference between the signals transmitted between the terminal and the base station through the first satellite and the second satellite, or based on the propagation delay difference between the signal and the first satellite and the second satellite.

[0373] In some implementations, the time difference between the terminal and the base station via the signals transmitted through the first satellite and the second satellite is determined by the synchronization unit 112 in one or more of the following ways:

[0374] The synchronization unit 112 determines the reception time difference when the terminal receives the same downlink signal transmitted by the base station through the first satellite and the second satellite, respectively;

[0375] The synchronization unit 112 subtracts the transmission time difference of the base station from the reception time difference of the different downlink signals received by the terminal from the base station through the first satellite and the second satellite respectively.

[0376] The synchronization unit 112 receives the reception time difference of the same uplink signal transmitted by the terminal through the first satellite and the second satellite, respectively, as detected by the base station.

[0377] The synchronization unit 112 receives the reception time difference of the different uplink signals transmitted by the terminal through the first satellite and the second satellite respectively, which is detected by the base station, and subtracts the transmission time difference of the different uplink signals transmitted by the terminal from the reception time difference.

[0378] In some implementations, the propagation delay difference of the signal between the terminal and the first and second satellites is determined by the synchronization unit 112 in one or more of the following ways:

[0379] The synchronization unit 112 determines the time difference between receiving the same downlink signal sent by the first satellite and the second satellite;

[0380] The synchronization unit 112 determines the time difference between receiving different downlink signals sent by the first satellite and the second satellite, and subtracts the transmission time difference between the first satellite and the second satellite from the time difference between receiving the different downlink signals.

[0381] The synchronization unit 112 receives a first reception time when the first satellite detects the uplink signal sent by the terminal, and a second reception time when the second satellite detects the same uplink signal sent by the terminal, and calculates the difference between the first reception time and the second reception time.

[0382] The synchronization unit 112 receives a first reception time when the first satellite detects the uplink signal sent by the terminal, and a second reception time when the second satellite detects different uplink signals sent by the terminal, and calculates the difference between the first reception time and the second reception time, and subtracts the transmission time difference of the different uplink signals sent by the terminal from the difference.

[0383] In some implementations, prior to performing the synchronization process with the second satellite cell, the synchronization unit 112 is further configured to acquire one or a combination of the following information:

[0384] The community signage remains unchanged;

[0385] The second satellite begins beam coverage of the area to which the terminal belongs;

[0386] Information on the time when the first satellite ceases beam coverage of the area to which the terminal belongs;

[0387] The time information or indication information for the terminal to begin the synchronization process with the second satellite cell;

[0388] Instructions to begin synchronizing with the second satellite cell;

[0389] The ephemeris information of the second satellite;

[0390] The common timing advance value information of the second satellite;

[0391] Downlink signal configuration information;

[0392] Uplink signal configuration information;

[0393] The base station transmits downlink signals via the first satellite and the second satellite respectively, using the transmission time difference information.

[0394] In some implementations, when one or a combination of the information is received, the synchronization unit determining unit 111 determines that the synchronization process between the terminal and the second satellite cell needs to be performed.

[0395] In some embodiments, the synchronization unit 112 is further configured to:

[0396] According to the network configuration, synchronization with the second satellite cell begins;

[0397] Alternatively, after the terminal obtains the updated timing advance value, it immediately begins to synchronize with the second satellite cell;

[0398] Alternatively, upon receiving an instruction from the network side, synchronization with the second satellite cell can begin.

[0399] On the network side, see Figure 12 Another synchronization device in a satellite network provided in this application embodiment includes:

[0400] The first unit 121 is used to determine that the cell identifiers of the first satellite cell and the second satellite cell are the same; wherein, the first satellite cell is the cell of the current serving terminal;

[0401] The second unit 122 is used to transmit signals to the terminal via the first satellite and the second satellite respectively, so that the terminal obtains and performs a synchronization process with the second satellite cell based on the time difference between the signals transmitted through the first satellite and the second satellite between the terminal and the base station, or the propagation delay difference between the signal and the first satellite and the second satellite.

[0402] When the synchronization process between the terminal and the second satellite cell is performed based on the time difference between the signals transmitted through the first satellite and the second satellite between the terminal and the base station, the network-side synchronization device provided in the above-described embodiments of this application can be an access network device such as a base station; when the synchronization process between the terminal and the second satellite cell is performed based on the propagation delay difference between the signal and the first satellite and the second satellite, the network-side synchronization device provided in the above-described embodiments of this application can be a satellite device.

[0403] In some embodiments, the second unit 122 transmits signals to the terminal via the first satellite and the second satellite, respectively, enabling the terminal to obtain the time difference between the signals transmitted through the first satellite and the second satellite between the terminal and the base station, including:

[0404] The second unit 122 transmits the same downlink signal to the terminal through the first satellite and the second satellite respectively, so that the terminal determines the reception time difference of the same downlink signal transmitted through the first satellite and the second satellite respectively;

[0405] The second unit 122 transmits different downlink signals to the terminal through the first satellite and the second satellite respectively, and notifies the terminal of the transmission time difference of the different downlink signals, so that the terminal subtracts the transmission time difference of the different downlink signals from the reception time difference of the different downlink signals transmitted through the first satellite and the second satellite respectively.

[0406] The second unit 122 receives the same uplink signal transmitted by the terminal through the first satellite and the second satellite respectively, detects the reception time difference of the same uplink signal, and sends the reception time difference to the terminal.

[0407] The second unit 122 receives different uplink signals transmitted by the terminal through the first satellite and the second satellite respectively, detects the reception time difference of the different uplink signals, and sends the reception time difference to the terminal.

[0408] In some embodiments, the second unit 122 transmits signals to the terminal via the first satellite and the second satellite, respectively, enabling the terminal to obtain the propagation delay difference of the signal between the terminal and the first satellite and the second satellite, including:

[0409] The second unit 122 sends the same downlink signal to the terminal through the first satellite and the second satellite, so that the terminal determines the time difference of receiving the same downlink signal sent by the first satellite and the second satellite;

[0410] The second unit 122 sends different downlink signals and the transmission time of the downlink signals to the terminal through the first satellite and the second satellite, so that the terminal determines the time difference of receiving the different downlink signals sent by the first satellite and the second satellite, and subtracts the transmission time difference of the different downlink signals sent by the first satellite and the second satellite from the time difference.

[0411] The second unit 122 receives the same uplink signal sent by the terminal through the first satellite and the second satellite, and sends the first reception time of the same uplink signal to the terminal through the first satellite, and sends the second reception time of the same uplink signal to the terminal through the second satellite, so that the terminal calculates the difference between the first reception time and the second reception time.

[0412] The second unit 122 receives different uplink signals sent by the terminal through the first satellite and the second satellite, and sends the first reception time of the uplink signal to the terminal through the first satellite and the second reception time of the uplink signal to the terminal through the second satellite, so that the terminal calculates the difference between the first reception time and the second reception time, and subtracts the transmission time difference of the different uplink signals sent by the terminal from the difference.

[0413] In some embodiments, the second unit 122 is further configured to send one or a combination of the following information to the terminal:

[0414] The community signage remains unchanged;

[0415] The second satellite begins beam coverage of the area to which the terminal belongs;

[0416] Information on the time when the first satellite ceases beam coverage of the area to which the terminal belongs;

[0417] The time information or indication information for the terminal to begin the synchronization process with the second satellite cell;

[0418] Instructions to begin synchronizing with the second satellite cell;

[0419] The ephemeris information of the second satellite;

[0420] The common timing advance value information of the second satellite;

[0421] Downlink signal configuration information;

[0422] Uplink signal configuration information;

[0423] The base station transmits downlink signals via the first satellite and the second satellite respectively, using the transmission time difference information.

[0424] It should be noted that the division of units in the embodiments of this application is illustrative and only represents one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated units described above can be implemented in hardware or as software functional units.

[0425] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0426] It should be noted that the apparatus provided in this embodiment of the invention can implement all the method steps implemented in the above method embodiment and can achieve the same technical effect. Therefore, the parts and beneficial effects that are the same as those in the method embodiment will not be described in detail here.

[0427] This application provides a processor-readable storage medium storing a computer program that causes the processor to execute any of the methods provided in the above-described embodiments of this application.

[0428] The processor-readable storage medium can be any available medium or data storage device that the processor can access, including but not limited to magnetic memory (e.g., floppy disk, hard disk, magnetic tape, magneto-optical disk (MO)), optical memory (e.g., CD, DVD, BD, HVD), and semiconductor memory (e.g., ROM, EPROM, EEPROM, non-volatile memory (NAND FLASH), solid-state drive (SSD)).

[0429] This application also provides a computer program product or computer program that includes computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform any of the methods described in the above embodiments. The program product may employ any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof.

[0430] It should be understood that:

[0431] The access technology used by entities in a communication network to transmit traffic can be any suitable current or future technology, such as WLAN (Wireless Local Access Network), WiMAX (Microwave Access Global Interoperability), LTE, LTE-A, 5G, Bluetooth, infrared, etc.; in addition, embodiments may also apply wired technologies, such as IP-based access technologies, such as wired networks or fixed lines.

[0432] An embodiment suitable for implementation as software code or as part thereof and for operation using a processor or processing function is independent of the software code and can be specified using any known or future-developed programming language, such as high-level programming languages ​​such as Objective-C, C, C++, C#, Java, Python, Javascript, other scripting languages, etc., or low-level programming languages ​​such as machine language or assembler.

[0433] The implementation of the embodiments is hardware-independent and can be implemented using any known or future-developed hardware technology or any combination thereof, such as microprocessors or CPUs (central processing units), MOS (metal-oxide-semiconductor), CMOS (complementary MOS), BiMOS (bipolar MOS), BiCMOS (bipolar CMOS), ECL (emitter-coupled logic), and / or TTL (transistor-transistor logic).

[0434] The embodiments may be implemented as individual devices, apparatuses, units, components or functions, or in a distributed manner. For example, one or more processors or processing functions may be used or shared in the process, or one or more processing segments or processing portions may be used and shared in the process, wherein one or more physical processors may be used to implement one or more processing portions dedicated to a particular process as described.

[0435] The device can be implemented by a semiconductor chip, a chipset, or a (hardware) module that includes such a chip or chipset.

[0436] The implementation can also be implemented as any combination of hardware and software, such as ASIC (Application-Specific IC (Integrated Circuit)) components, FPGA (Field Programmable Gate Array) or CPLD (Complex Programmable Logic Device) components or DSP (Digital Signal Processor) components.

[0437] The embodiments can also be implemented as computer program products, including a computer-usable medium in which computer-readable program code is embodied, the computer-usable program code being adapted to perform the processes described in the embodiments, wherein the computer-usable medium may be a non-transitory medium.

[0438] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0439] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0440] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0441] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0442] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A synchronization method in a satellite network, characterized in that, When the satellites providing beam coverage for the area where the terminal is located change, but the cell remains unchanged, the method includes: The cell identifiers of the first satellite cell and the second satellite cell are determined to be the same; wherein, the first satellite cell is the cell of the currently serving terminal; and the first satellite cell and the second satellite cell are the same cell; Based on the time difference between the signals transmitted between the terminal and the base station via the first satellite and the second satellite, or based on the propagation delay difference between the terminal and the first satellite and the second satellite, the synchronization process between the terminal and the second satellite cell is performed.

2. The method according to claim 1, characterized in that, The time difference between the terminal and the base station through the signals transmitted via the first satellite and the second satellite is determined by one or more of the following methods: The terminal determines the reception time difference when it receives the same downlink signal transmitted by the base station through the first satellite and the second satellite, respectively. The terminal subtracts the transmission time difference of the base station from the reception time difference of the different downlink signals received by the terminal from the base station through the first satellite and the second satellite respectively. The terminal receives the reception time difference of the same uplink signal transmitted by the terminal through the first satellite and the second satellite, respectively, as detected by the base station. The terminal receives the reception time difference of the different uplink signals transmitted by the terminal through the first satellite and the second satellite, respectively, detected by the base station, and subtracts the transmission time difference of the different uplink signals from the reception time difference.

3. The method according to claim 1, characterized in that, The propagation delay difference of the signal between the terminal and the first and second satellites is determined by one or more of the following methods: The terminal determines the time difference between receiving the same downlink signal sent by the first satellite and the second satellite; The terminal determines the time difference between receiving different downlink signals sent by the first satellite and the second satellite, and subtracts the transmission time difference between the first satellite and the second satellite from the time difference. The terminal receives a first reception time when the first satellite detects the uplink signal sent by the terminal, and a second reception time when the second satellite detects the same uplink signal sent by the terminal, and calculates the difference between the first reception time and the second reception time. The terminal receives a first reception time when the first satellite detects an uplink signal sent by the terminal, and a second reception time when the second satellite detects different uplink signals sent by the terminal. The terminal calculates the difference between the first reception time and the second reception time, and subtracts the transmission time difference of the different uplink signals sent by the terminal from the difference.

4. The method according to claim 1, characterized in that, Before performing the synchronization process with the second satellite cell, the method further includes obtaining one or a combination of the following information: The community signage remains unchanged; The second satellite begins beam coverage of the area to which the terminal belongs; Information on the time when the first satellite ceases beam coverage of the area to which the terminal belongs; The time information or indication information for the terminal to begin the synchronization process with the second satellite cell; Instructions to begin synchronizing with the second satellite cell; The ephemeris information of the second satellite; The common timing advance value information of the second satellite; Downlink signal configuration information; Uplink signal configuration information; The base station transmits downlink signals via the first satellite and the second satellite respectively, using the transmission time difference information.

5. The method according to claim 4, characterized in that, When one or a combination of the information is received, it is determined that the synchronization process between the terminal and the second satellite cell needs to be performed.

6. The method according to claim 1, characterized in that, The method further includes: According to the network configuration, synchronization with the second satellite cell begins; Alternatively, after the terminal obtains the updated timing advance value, it immediately begins to synchronize with the second satellite cell; Alternatively, upon receiving an instruction from the network side, synchronization with the second satellite cell can begin.

7. A synchronization method in a satellite network, characterized in that, When the satellites providing beam coverage for the area where the terminal is located change, but the cell remains unchanged, the method includes: The cell identifiers of the first satellite cell and the second satellite cell are determined to be the same; wherein, the first satellite cell is the cell of the currently serving terminal; and the first satellite cell and the second satellite cell are the same cell; Signals are transmitted to the terminal via the first satellite and the second satellite, respectively, so that the terminal can obtain and perform a synchronization process with the second satellite cell based on the time difference between the signals transmitted between the terminal and the base station via the first satellite and the second satellite, or the propagation delay difference between the signal and the first satellite and the second satellite.

8. The method according to claim 7, characterized in that, Signal transmission to the terminal is performed via the first satellite and the second satellite, respectively, enabling the terminal to obtain the time difference between the signals transmitted through the first satellite and the second satellite between the terminal and the base station, including: The same downlink signal is transmitted to the terminal via the first satellite and the second satellite respectively, so that the terminal determines the reception time difference of the same downlink signal transmitted via the first satellite and the second satellite respectively; Different downlink signals are transmitted to the terminal via the first satellite and the second satellite respectively, and the transmission time difference of the different downlink signals is notified to the terminal, so that the terminal will subtract the transmission time difference of the different downlink signals from the reception time difference of the different downlink signals transmitted via the first satellite and the second satellite respectively. The terminal receives the same uplink signal transmitted through the first satellite and the second satellite respectively, detects the reception time difference of the same uplink signal, and sends the reception time difference to the terminal. The terminal receives different uplink signals transmitted through the first satellite and the second satellite, respectively, detects the reception time difference of the different uplink signals, and sends the reception time difference to the terminal.

9. The method according to claim 7, characterized in that, Signal transmission to the terminal is performed via the first satellite and the second satellite, respectively, enabling the terminal to acquire the propagation delay difference of the signal between the terminal and the first satellite and the second satellite, including: The terminal can determine the time difference between receiving the same downlink signal from the first satellite and the second satellite by sending the same downlink signal to the terminal via the first satellite and the second satellite. Different downlink signals and their transmission times are sent to the terminal via the first satellite and the second satellite, so that the terminal determines the time difference between receiving the different downlink signals sent by the first satellite and the second satellite, and subtracts the transmission time difference between the first satellite and the second satellite from the time difference. The terminal receives the same uplink signal sent by the terminal through the first satellite and the second satellite, and sends the first reception time of the same uplink signal to the terminal through the first satellite, and sends the second reception time of the same uplink signal to the terminal through the second satellite, so that the terminal calculates the difference between the first reception time and the second reception time. The terminal receives different uplink signals sent by the first satellite and the second satellite, and sends the first reception time of the uplink signal to the terminal via the first satellite and the second reception time of the uplink signal to the terminal via the second satellite. The terminal calculates the difference between the first reception time and the second reception time, and subtracts the transmission time difference of the different uplink signals sent by the terminal from the difference.

10. The method according to claim 7, characterized in that, The method further includes sending one or a combination of the following information to the terminal: The community signage remains unchanged; The second satellite begins beam coverage of the area to which the terminal belongs; Information on the time when the first satellite ceases beam coverage of the area to which the terminal belongs; The time information or indication information for the terminal to begin the synchronization process with the second satellite cell; Instructions to begin synchronizing with the second satellite cell; The ephemeris information of the second satellite; The common timing advance value information of the second satellite; Downlink signal configuration information; Uplink signal configuration information; The base station transmits downlink signals via the first satellite and the second satellite respectively, using the transmission time difference information.

11. A synchronization device in a satellite network, characterized in that, The device includes a memory, a transceiver, and a processor. A memory for storing computer programs; a transceiver for sending and receiving data under the control of the processor; and a processor for reading the computer programs from the memory and performing the following operations: When the satellite providing beam coverage for the area where the terminal is located changes, but the cell remains unchanged, it is determined that the cell identifiers of the first satellite cell and the second satellite cell are the same; wherein, the first satellite cell is the cell currently serving the terminal; the first satellite cell and the second satellite cell are the same cell; Based on the time difference between the signals transmitted between the terminal and the base station via the first satellite and the second satellite, or based on the propagation delay difference between the terminal and the first satellite and the second satellite, the synchronization process between the terminal and the second satellite cell is performed.

12. The apparatus according to claim 11, characterized in that, The time difference between the terminal and the base station through the signals transmitted via the first satellite and the second satellite is determined by one or more of the following methods: The terminal determines the reception time difference when it receives the same downlink signal transmitted by the base station through the first satellite and the second satellite, respectively. The terminal subtracts the transmission time difference of the base station from the reception time difference of the different downlink signals received by the terminal from the base station through the first satellite and the second satellite respectively. The terminal receives the reception time difference of the same uplink signal transmitted by the terminal through the first satellite and the second satellite, respectively, as detected by the base station. The terminal receives the reception time difference of the different uplink signals transmitted by the terminal through the first satellite and the second satellite, respectively, detected by the base station, and subtracts the transmission time difference of the different uplink signals from the reception time difference.

13. The apparatus according to claim 11, characterized in that, The propagation delay difference of the signal between the terminal and the first and second satellites is determined by one or more of the following methods: The terminal determines the time difference between receiving the same downlink signal sent by the first satellite and the second satellite; The terminal determines the time difference between receiving different downlink signals sent by the first satellite and the second satellite, and subtracts the transmission time difference between the first satellite and the second satellite from the time difference. The terminal receives a first reception time when the first satellite detects the uplink signal sent by the terminal, and a second reception time when the second satellite detects the same uplink signal sent by the terminal, and calculates the difference between the first reception time and the second reception time. The terminal receives a first reception time when the first satellite detects an uplink signal sent by the terminal, and a second reception time when the second satellite detects different uplink signals sent by the terminal. The terminal calculates the difference between the first reception time and the second reception time, and subtracts the transmission time difference of the different uplink signals sent by the terminal from the difference.

14. The apparatus according to claim 11, characterized in that, Before performing the synchronization process with the second satellite cell, the processor is further configured to read the computer program in the memory and obtain one or a combination of the following information: The community signage remains unchanged; The second satellite begins beam coverage of the area to which the terminal belongs; Information on the time when the first satellite ceases beam coverage of the area to which the terminal belongs; The time information or indication information for the terminal to begin the synchronization process with the second satellite cell; Instructions to begin synchronizing with the second satellite cell; The ephemeris information of the second satellite; The common timing advance value information of the second satellite; Downlink signal configuration information; Uplink signal configuration information; The base station transmits downlink signals via the first satellite and the second satellite respectively, using the transmission time difference information.

15. The apparatus according to claim 14, characterized in that, When one or a combination of the information is received, the processor determines that the synchronization process between the terminal and the second satellite cell needs to be performed.

16. The apparatus according to claim 11, characterized in that, The processor is also configured to read the computer program in the memory and perform the following operations: According to the network configuration, synchronization with the second satellite cell begins; Alternatively, after the terminal obtains the updated timing advance value, it immediately begins to synchronize with the second satellite cell; Alternatively, upon receiving an instruction from the network side, synchronization with the second satellite cell can begin.

17. A synchronization device in a satellite network, characterized in that, The device includes a memory, a transceiver, and a processor. A memory for storing computer programs; a transceiver for sending and receiving data under the control of the processor; and a processor for reading the computer programs from the memory and performing the following operations: When the satellite providing beam coverage for the area where the terminal is located changes, but the cell remains unchanged, it is determined that the cell identifiers of the first satellite cell and the second satellite cell are the same; wherein, the first satellite cell is the cell currently serving the terminal; the first satellite cell and the second satellite cell are the same cell; Signals are transmitted to the terminal via the first satellite and the second satellite, respectively, so that the terminal can obtain and perform a synchronization process with the second satellite cell based on the time difference between the signals transmitted between the terminal and the base station via the first satellite and the second satellite, or the propagation delay difference between the signal and the first satellite and the second satellite.

18. The apparatus according to claim 17, characterized in that, Signal transmission to the terminal is performed via the first satellite and the second satellite, respectively, enabling the terminal to obtain the time difference between the signals transmitted through the first satellite and the second satellite between the terminal and the base station, including: The same downlink signal is transmitted to the terminal via the first satellite and the second satellite respectively, so that the terminal determines the reception time difference of the same downlink signal transmitted via the first satellite and the second satellite respectively; Different downlink signals are transmitted to the terminal via the first satellite and the second satellite respectively, and the transmission time difference of the different downlink signals is notified to the terminal, so that the terminal will subtract the transmission time difference of the different downlink signals from the reception time difference of the different downlink signals transmitted via the first satellite and the second satellite respectively. The terminal receives the same uplink signal transmitted through the first satellite and the second satellite respectively, detects the reception time difference of the same uplink signal, and sends the reception time difference to the terminal. The terminal receives different uplink signals transmitted through the first satellite and the second satellite, respectively, detects the reception time difference of the different uplink signals, and sends the reception time difference to the terminal.

19. The apparatus according to claim 17, characterized in that, Signal transmission to the terminal is performed via the first satellite and the second satellite, respectively, enabling the terminal to acquire the propagation delay difference of the signal between the terminal and the first satellite and the second satellite, including: The terminal can determine the time difference between receiving the same downlink signal from the first satellite and the second satellite by sending the same downlink signal to the terminal via the first satellite and the second satellite. Different downlink signals and their transmission times are sent to the terminal via the first satellite and the second satellite, so that the terminal determines the time difference between receiving the different downlink signals sent by the first satellite and the second satellite, and subtracts the transmission time difference between the first satellite and the second satellite from the time difference. The terminal receives the same uplink signal sent by the terminal through the first satellite and the second satellite, and sends the first reception time of the same uplink signal to the terminal through the first satellite, and sends the second reception time of the same uplink signal to the terminal through the second satellite, so that the terminal calculates the difference between the first reception time and the second reception time. The terminal receives different uplink signals sent by the first satellite and the second satellite, and sends the first reception time of the uplink signal to the terminal via the first satellite and the second reception time of the uplink signal to the terminal via the second satellite. The terminal calculates the difference between the first reception time and the second reception time, and subtracts the transmission time difference of the different uplink signals sent by the terminal from the difference.

20. The apparatus according to claim 17, characterized in that, The processor is also configured to read the computer program in the memory and send one or a combination of the following information to the terminal: The community signage remains unchanged; The second satellite begins beam coverage of the area to which the terminal belongs; Information on the time when the first satellite ceases beam coverage of the area to which the terminal belongs; The time information or indication information for the terminal to begin the synchronization process with the second satellite cell; Instructions to begin synchronizing with the second satellite cell; The ephemeris information of the second satellite; The common timing advance value information of the second satellite; Downlink signal configuration information; Uplink signal configuration information; The base station transmits downlink signals via the first satellite and the second satellite respectively, using the transmission time difference information.

21. A synchronization device in a satellite network, characterized in that, The device includes: The determining unit is configured to determine that the cell identifiers of a first satellite cell and a second satellite cell are the same when the satellite providing beam coverage for the area to which the terminal belongs changes, but the cell remains unchanged; wherein the first satellite cell is the cell of the currently serving terminal; and the first satellite cell and the second satellite cell are the same cell; The synchronization unit is used to perform a synchronization process between the terminal and the second satellite cell based on the time difference between the signals transmitted between the terminal and the base station through the first satellite and the second satellite, or based on the propagation delay difference between the signal and the first satellite and the second satellite.

22. A synchronization device in a satellite network, characterized in that, The device includes: The first unit is used to determine that the cell identifiers of the first satellite cell and the second satellite cell are the same when the satellite providing beam coverage for the area to which the terminal belongs changes, but the cell does not change; wherein, the first satellite cell is the cell of the currently serving terminal; and the first satellite cell and the second satellite cell are the same cell; The second unit is used to transmit signals to the terminal via the first satellite and the second satellite respectively, so that the terminal obtains and performs a synchronization process with the second satellite cell based on the time difference between the signals transmitted through the first satellite and the second satellite between the terminal and the base station, or the propagation delay difference between the signal and the first satellite and the second satellite.

23. A processor-readable storage medium, characterized in that, The processor-readable storage medium stores a computer program for causing the processor to perform the method according to any one of claims 1 to 10.

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