Communication method and communication apparatus

Abstract

This application provides a communication method and a communication apparatus. The method includes a terminal device receiving indication information from a first network device, the terminal device being a terminal device accessed through a first cell of the first network device. The indication information instructs the terminal device to measure a reference signal transmitted from a second network device through the first cell. The terminal device receives the reference signal transmitted from the second network device through the first cell, measures the signal quality of the reference signal based on the indication information, and transmits the signal quality of the reference signal to the first network device. This approach can reduce the probability of wireless link failure due to handover operations by the terminal device.

Description

[0001] This application is a divisional application. The original application has the application number 202410078713.3 and the original application date is January 18, 2024. The entire contents of the original application are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and in particular to a communication method and communication device. Background Technology

[0003] Non-terrestrial networks (NTNs) are communication systems that utilize non-terrestrial network equipment. These include satellites, drones, and high-altitude platform station (HAPS) communication systems. NTNs offer advantages such as wide coverage, long communication distances, high reliability, high flexibility, and high throughput. They are unaffected by geographical environment, weather conditions, or natural disasters and have been widely applied in aviation, maritime, and military communications. Introducing NTNs into 5G mobile networks and subsequent evolutionary system architectures such as 6G can significantly improve user experience. On one hand, NTN networks can enhance communication reliability, providing more stable communication services for users in high-speed mobile scenarios such as trains and airplanes. On the other hand, NTN networks can provide wider coverage, such as providing communication services for users at sea or in deserts. Furthermore, NTN networks can provide more data transmission resources and support a larger number of connections. Therefore, the importance of NTNs will continue to rise in the future. When NTN is introduced into 5G mobile networks and subsequent system architectures, the switching technology for terminal devices needs further research. Summary of the Invention

[0004] This application provides a communication method and a communication device to reduce the probability of wireless link failure caused by terminal devices performing handover.

[0005] In a first aspect, embodiments of this application provide a communication method, which can be executed by a terminal device or a module (such as a chip) in the terminal device, wherein the terminal device is a terminal device accessing a first cell through a first network device. The method includes: receiving indication information from a first network device, the indication information instructing the terminal device to measure a reference signal transmitted from a second network device through the first cell, and receiving the reference signal from the second network device in the first cell. After receiving the reference signal, measuring the signal quality of the reference signal and sending the signal quality of the reference signal to the first network device. In this scheme, the terminal device accesses the first cell through the first network device, measures the quality of the reference signal transmitted from the second network device through the first cell according to the indication information from the first network device, and sends the reference signal quality to the network device. This avoids handover failure or reduced link quality after handover due to not knowing the signal quality of the second network device, thus reducing the probability of wireless link failure due to handover. Furthermore, according to the above scheme, after the network device receives the reference signal, it can determine the handover strategy of the terminal device based on the quality of the reference signal. For example, if a network device determines that the quality of the reference signal is poor, it can instruct the terminal device not to continue switching to access the first cell through the second network device, or it can instruct the terminal device to switch to another cell with a better signal, such as a neighboring cell of the first cell.

[0006] In one possible implementation, the terminal device receives a first time and a second time from the first network device, wherein the first time indicates the time when the first network device stops providing service to the first cell, and the second time indicates the time when the second network device starts providing service to the first cell, wherein the second time is less than or equal to the first time. Between the second time and the first time, the terminal device measures the signal quality of a reference signal. In this scheme, the terminal device can determine when to measure the reference signal of the first cell of the second network device using the received first and second times.

[0007] In one possible implementation, receiving indication information from the first network device includes: the terminal device receiving measurement configuration information from the first network device, the measurement configuration information including the aforementioned indication information, and the measurement configuration information being used to configure the terminal device to measure the reference signal. In this scheme, the terminal device can obtain the aforementioned indication information by receiving the measurement configuration information without requiring additional signaling, thereby saving system signaling overhead and reducing the complexity of terminal device processing.

[0008] In one possible implementation, the measurement configuration information further includes measurement object and report configuration information, wherein the measurement object is the measurement object corresponding to the first cell. In this scheme, the terminal device can explicitly specify that it should perform measurements according to the measurement object corresponding to the first cell.

[0009] In one possible implementation, the terminal device measures the signal quality of the reference signal based on the indication information, including: the terminal device receiving first SMTC information and second SMTC information from a first network device; the terminal device measuring the reference signal of a first cell and the reference signal of neighboring cells of the first cell based on the first SMTC information; and the terminal device measuring the reference signal of neighboring cells of the first cell based on the second SMTC information.

[0010] In one possible implementation, the terminal device measures the reference signal of the first cell and the reference signal of the neighboring cells of the first cell of the second network device based on the first SMTC information, including: between a second time and the first time, the terminal device measures the reference signal of the first cell and the reference signal of the neighboring cells of the first cell of the second network device based on the first SMTC information.

[0011] In one possible implementation, the terminal device measures the reference signal of the neighboring cell of the first cell based on the second SMTC information, including: the terminal device measures the reference signal of the neighboring cell of the first cell based on the second SMTC information before the second time moment or after the first time moment.

[0012] In one possible implementation, measuring the signal quality of the reference signal between the second time and the first time includes: the terminal device measuring the signal quality of a first cell from a second network device between the second time and the first time, and measuring the signal quality of a first cell from a first network device between the second time and the first time.

[0013] In one possible implementation, the terminal device maintains and measures the signal quality of the first cell of the second network device and the signal quality of the first cell of the first network device between the second time and the first time.

[0014] In one possible implementation, the terminal device receives first condition information from a first network device, the first condition information including radio resource configuration information of a first candidate cell and execution conditions for handover to the first candidate cell; the terminal device receives second condition information from the first network device, the second condition information being used to indicate that when the signal quality of the measured first cell reference signal of the second network device is lower than a first threshold, conditional handover to the first candidate cell is performed.

[0015] In one possible implementation, the terminal device switches from accessing the first cell via a first network device to accessing the first cell via a second network device at a third time point, which is between the second time point and the first time point.

[0016] Secondly, embodiments of this application provide a communication method that can be executed by a first network device or a module (such as a chip) within the first network device. The method includes: the network device sending indication information to a terminal device, the indication information instructing the terminal device to measure a reference signal from a first cell of a second network device, the first cell being the cell the terminal device accesses through the first network device; the network device also receiving the signal quality of the reference signal from the terminal device. Therefore, the first network device can assess whether to switch the terminal device to the second network device based on the signal quality. If the reference signal quality from the first cell of the second network device is poor, the terminal device can avoid continuing to switch to access the first cell through the second network device; for example, the terminal device can switch to another cell with better signal quality, reducing the probability of wireless link failure due to the terminal device performing a handover.

[0017] In one possible implementation, the first network device sends a first time and a second time to the terminal device. The first time indicates the time when the first network device stops providing services to the first cell, and the second time indicates the time when the second network device starts providing services to the first cell, wherein the second time is less than or equal to the first time.

[0018] In one possible implementation, the first network device sends indication information to the terminal device, including: the first network device sending measurement configuration information to the terminal device, the measurement configuration information including the indication information, the measurement configuration information being used to configure the terminal device's measurement reference signal, the measurement configuration information including the measurement object and report configuration information, wherein the measurement object is the measurement object corresponding to the first cell.

[0019] In one possible implementation, the first network device sends first SMTC information and second SMTC information to the terminal device. The first SMTC information is used to measure the reference signal of the first cell of the second network device and the reference signal of the neighboring cells of the first cell. The second SMTC configuration information is used to measure the reference signal of the neighboring cells of the first cell.

[0020] In one possible implementation, a first network device sends first condition information to a terminal device, the first condition information including radio resource configuration information of a first candidate cell and execution conditions for handover to the first candidate cell; the first network device sends second condition information to the terminal device, the second condition information being used to indicate that when the signal quality of the reference signal of the first cell of the second network device is lower than a first threshold, conditional handover to the first candidate cell is performed.

[0021] For the beneficial effects of various implementation methods of the first network device, please refer to the beneficial effects of various implementation methods of the terminal device in the first aspect, which will not be repeated here.

[0022] Thirdly, embodiments of this application provide a communication method, which can be executed by a terminal device or a module (such as a chip) in the terminal device. The method includes: the terminal device receiving a first time and a second time from a first network device, wherein the first time indicates when the first network device stops providing service to a first cell, and the second time indicates when a second network device starts providing service to the first cell, wherein the second time is less than or equal to the first time; the terminal device receiving second indication information; and the terminal device determining, based on the second indication information, not to access the first cell through the second network device between the second time and the first time. In this scheme, it can be ensured that terminal devices in the first cell between the second time and the first time access the first cell through the first network device, thereby avoiding interference between terminal devices within the same cell caused by some terminal devices accessing the first cell through the first network device and others through the second network device.

[0023] In one possible implementation, the terminal device receives the second indication information through a first network device; or, it receives the second indication information through a second network device.

[0024] In one possible implementation, the second indication information is used to instruct the terminal device not to access the first cell through the second network device between the second time and the first time.

[0025] In one possible implementation, the second indication information is used to indicate that the second network device is the target network device of the first cell.

[0026] Fourthly, embodiments of this application provide a communication method, which can be executed by a first network device or a module (such as a chip) in the first network device. The method includes: the first network device sending a first time and a second time to a terminal device, wherein the first time indicates the time at which the first network device stops providing service to a first cell, and the second time indicates the time at which a second network device begins providing service to the first cell, wherein the second time is less than or equal to the first time; and the first network device sending second indication information to the terminal device, the second indication information being used to determine that the terminal device will not access the first cell through the second network device between the second time and the first time.

[0027] In one possible implementation, the second indication information is used to indicate that the second network device is the target network device of the first cell.

[0028] The beneficial effects of various implementation methods for the first network device can be found in the beneficial effects of various implementation methods for the third terminal device, and will not be elaborated further.

[0029] Fifthly, embodiments of this application provide a communication device, which may be a terminal device or a module (such as a chip) within the terminal device. This device has the function of implementing any of the methods described in the first aspect. This function can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the aforementioned function.

[0030] Sixthly, embodiments of this application provide a communication device, which may be a first network device or a module (such as a chip) within the first network device. This device has the function of implementing any of the methods described in the second aspect above. This function can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the aforementioned function.

[0031] In a seventh aspect, embodiments of this application provide a communication apparatus, including units or means for performing various steps of any of the implementation methods in the first to fourth aspects described above.

[0032] Eighthly, embodiments of this application provide a communication device, including a processor and an interface circuit. The processor is configured to communicate with other devices via the interface circuit and execute any of the implementation methods described in the first to fourth aspects. The processor may include one or more devices.

[0033] Ninthly, embodiments of this application provide a communication device including a processor coupled to a memory, the processor being configured to invoke a program stored in the memory to execute any of the implementation methods described in the first to fourth aspects. The memory may be located within or outside the device. Furthermore, the processor may be one or more.

[0034] In a tenth aspect, embodiments of this application provide a communication device including a memory; the memory is used to store computer instructions, and when the computer instructions are executed, the device performs any of the implementation methods of the first to fourth aspects described above.

[0035] In one possible implementation, the communication device further includes a processor for executing computer instructions stored in the memory.

[0036] Eleventhly, embodiments of this application also provide a computer program product, which includes a computer program or instructions that, when executed by a communication device, cause any of the implementation methods in the first to fourth aspects to be executed.

[0037] In a twelfth aspect, embodiments of this application also provide a computer-readable storage medium storing instructions that, when executed on a communication device, cause any of the implementation methods in the first to fourth aspects described above to be performed.

[0038] In a thirteenth aspect, embodiments of this application also provide a chip system, including: a processor for executing any of the implementation methods in the first to fourth aspects described above.

[0039] In a fourteenth aspect, embodiments of this application also provide a communication system, including a terminal device for executing any implementation of the method of the first aspect, and a first network device for executing any implementation of the method of the fourth aspect. Attached Figure Description

[0040] Figure 1(a) is a schematic diagram of the architecture of the communication system used in the embodiments of this application;

[0041] Figure 1(b) shows a schematic diagram of a network device;

[0042] Figure 2(a) is a schematic diagram of the NTN-based communication system architecture used in the embodiments of this application;

[0043] Figure 2(b) is another schematic diagram of the NTN-based communication system architecture applied in the embodiments of this application;

[0044] Figure 2(c) is another schematic diagram of the NTN-based communication system architecture used in the embodiments of this application;

[0045] Figure 3 A flowchart illustrating the communication method provided in an embodiment of this application;

[0046] Figure 4(a) is another flowchart illustrating the communication method provided in an embodiment of this application;

[0047] Figure 4(b) is another flowchart illustrating the communication method provided in the embodiments of this application;

[0048] Figure 4(c) is a schematic diagram of orbital information represented in Kepler orbital format according to an embodiment of this application;

[0049] Figure 4(d) is a schematic diagram of orbit information represented by state vectors according to an embodiment of this application.

[0050] Figure 5This is a schematic diagram of the structure of the communication device provided in the embodiments of this application;

[0051] Figure 6 This is another schematic diagram of the communication device provided in the embodiments of this application. Detailed Implementation

[0052] Figure 1(a) is a schematic diagram of the architecture of the communication system applied in the embodiment of this application. The communication system 1000 shown in Figure 1(a) includes a wireless access network 100 and a core network 200. Optionally, the communication system 1000 also includes an Internet 300. The wireless access network 100 may include at least one network device (110a-110c in Figure 1(a)) and at least one terminal device (120a-120i in Figure 1(a)). The terminal device is connected to the network device wirelessly, and the network device is connected to the core network wirelessly or via a wired connection. The core network device and the network device may be independent and different physical devices, or the functions of the core network device and the logical functions of the network device may be integrated on the same physical device, or a single physical device may integrate some of the functions of the core network device and some of the functions of the network device. Terminal devices and network devices may be interconnected via wired or wireless connections. Figure 1(a) is only a schematic diagram. This communication system may also include other network devices, such as wireless relay devices and wireless backhaul devices, which are not shown in Figure 1(a).

[0053] Network equipment is an access device that allows terminal devices to connect to a communication system via wired or wireless means. Network equipment can be a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next-generation NodeB (gNB) in 5G mobile communication systems, a next-generation base station in 6G mobile communication systems, a base station in future mobile communication systems, or an access node in a wireless fidelity (WiFi) system; it can also be a module or unit that performs some of the functions of a base station, for example, it can be a central unit (CU) or a distributed unit (DU). The CU here performs the functions of the radio resource control protocol and packet data convergence protocol (PDCP) of the base station, and can also perform the functions of the service data adaptation protocol (SDAP). The DU performs the functions of the radio link control layer and medium access control (MAC) layer of the base station, and can also perform some or all of the physical layer functions. For specific descriptions of the above-mentioned protocol layers, please refer to the relevant technical specifications of the 3rd generation partnership project (3GPP). The network equipment can be a macro base station (110a in Figure 1(a)), a micro base station or an indoor station (110b in Figure 1(a)), a high-altitude platform, an aircraft or a satellite (110c in Figure 1(a)), a relay node or a donor node, etc. The embodiments of this application do not limit the specific technology or specific equipment form used in the network equipment.

[0054] A terminal device is a device with wireless transceiver capabilities, capable of sending signals to or receiving signals from network devices. Terminal devices include, but are not limited to, terminal equipment, user equipment (UE), mobile stations, and mobile terminals. Terminal devices can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), the Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, and smart cities. Specifically, a terminal device can be a mobile phone, tablet computer, computer with wireless transceiver capabilities, wearable device, vehicle, aircraft, ship, robot, robotic arm, smart home device, etc. The embodiments of this application do not limit the specific technologies or device forms used in the terminal devices.

[0055] In this embodiment of the invention, the terminal device can have multiple states. For example, the terminal device can be in a connected state, where it can transmit data. In the connected state, the terminal device can establish connections with both the network device and the core network. The terminal device can also be in a deactivated state, where it can quickly establish a connection with the network device when data needs to be transmitted. For example, when a terminal device in the activated state needs data transmission, the network device can send a paging message, and the terminal device can quickly establish a connection with the network device upon receiving the paging message. In the deactivated state, the terminal device may not establish a connection with the network device, but a connection may be established between the network device and the core network. The terminal device can also be in an idle state, where neither the terminal device nor the network device needs to establish a connection with the core network.

[0056] Network devices and terminal devices can be fixed in location or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can be deployed on aircraft, balloons, and artificial satellites. The embodiments of this application do not limit the application scenarios of the network devices and terminal devices.

[0057] The roles of network devices and terminal devices can be relative. For example, the aircraft or satellite 110c in Figure 1(a) can be configured as a mobile network device. For terminal devices 120i that access the wireless access network 100 via 110c, 110c is a network device. However, for network device 110a, 110c can also be a terminal device, meaning that 110a and 110c communicate via a wireless air interface protocol. Of course, 110a and 110c can also communicate via a network device-to-network device interface protocol. In this case, relative to 110a, 110c can also be a network device. Therefore, both network devices and terminal devices can be collectively referred to as communication devices. 110a-110c in Figure 1(a) can be called communication devices with network device functions, and 120a-120i in Figure 1(a) can be called communication devices with terminal device functions.

[0058] Communication between network devices and terminal devices, between network devices, and between terminal devices can be conducted using licensed spectrum, unlicensed spectrum, or both simultaneously. Communication can be conducted using spectrum below 6 GHz, spectrum above 6 GHz, or both simultaneously. The embodiments of this application do not limit the spectrum resources used for wireless communication.

[0059] In the embodiments of this application, the functions of the network device can be executed by modules (such as chips) within the network device, or by a control subsystem that includes network device functions. This control subsystem, including network device functions, can be a control center in the aforementioned application scenarios such as smart grids, industrial control, intelligent transportation, and smart cities. Similarly, the functions of the terminal device can be executed by modules (such as chips or modems) within the terminal device, or by a device that includes terminal device functions.

[0060] In this application, the network device sends downlink signals or downlink information to the terminal device, with the downlink information carried on the downlink channel; the terminal device sends uplink signals or uplink information to the network device, with the uplink information carried on the uplink channel. In order to communicate with the network device, the terminal device needs to establish a wireless connection with a cell controlled by the network device. The cell with which the terminal device has established a wireless connection is called the serving cell of that terminal device.

[0061] In this application, the numbering of terms is generally for the convenience of differentiation. The numbering does not mean that the terms have a difference in order or priority. For example, "first network device" and "second network device" are usually only used to distinguish between the two network devices and should not be construed as limiting the implementation process of the embodiments of this application.

[0062] Figure 1(b) shows a schematic diagram of a network device. As shown in Figure 1(b), the network device includes one or more CUs, one or more DUs, and one or more radio units (RUs). For clarity, only one CU, DU, and RU are shown in Figure 1(b). The CU is used to connect to the core network and one or more DUs. Optionally, the CU may have some of the core network's functions. The CU may include a CU-control plane (CP) and a CU-user plane (UP).

[0063] The CU and DU can be configured according to the protocol layer functions of the wireless network they implement: for example, the CU can be configured to implement the functions of the PDCP layer and above (such as the radio resource control (RRC) layer and / or SDAP layer); the DU can be configured to implement the functions of the protocol layers below the PDCP layer (such as the radio link control (RLC) layer, MAC layer, and / or physical (PHY) layer). Alternatively, the CU can be configured to implement the functions of the PDCP layer and above (such as the RRC layer and / or SDAP layer), and the DU can be configured to implement the functions of the PDCP layer and below (such as the RLC layer, MAC layer, and / or PHY layer).

[0064] The above CU and DU configurations are merely examples; the functions of the CU and DU can be configured as needed. For instance, the CU or DU can be configured to have more protocol layer functions, or only some protocol layer processing functions. For example, some RLC layer functions and protocol layer functions above the RLC layer can be placed in the CU, while the remaining RLC layer functions and protocol layer functions below the RLC layer can be placed in the DU. Furthermore, the functions of the CU or DU can be divided according to service type or other system requirements, such as by latency. Functions that require low latency can be placed in the DU, while functions that do not require low latency can be placed in the CU.

[0065] DU and RU can cooperate to implement the functions of the PHY layer. A DU can be connected to one or more RUs. The functions of DU and RU can be configured in various ways depending on the design. For example, a DU can be configured to implement baseband functions, and an RU can be configured to implement mid-RF functions. Another example is that a DU can be configured to implement higher-level functions in the PHY layer, and an RU can be configured to implement lower-level functions in the PHY layer, or to implement both lower-level and RF functions. Higher-level functions in the physical layer can include a portion of the physical layer's functions that are closer to the MAC layer, while lower-level functions in the physical layer can include another portion of the physical layer's functions that are closer to the mid-RF side.

[0066] As described in the background section, NTN is introduced into 5G systems and subsequent system architectures. This application describes embodiments using satellites as an example of non-terrestrial network equipment in NTN; it should be understood that non-terrestrial network equipment in NTN can be other non-terrestrial network equipment.

[0067] Generally, satellites can be categorized into high-Earth orbit (GEO) satellites and low-Earth orbit (LEO) satellites based on their orbital altitude. GSO satellites, also known as geosynchronous orbit (GSO) satellites, move at the same speed as the Earth's rotation, thus remaining stationary relative to the ground. Consequently, GSO satellite cells have a relatively large coverage area, typically with a cell diameter of 500 kilometers. LEO satellites, on the other hand, move faster relative to the ground, and therefore their service coverage area also shifts. Accordingly, the cells covered by LEO satellites can be divided into quasi-stationary cells and moving cells. A quasi-stationary cell is formed by a moving satellite adjusting its beam, and the resulting cell remains stationary on the ground for a certain period. A moving cell, however, is formed when the satellite does not dynamically adjust its beam direction, and the cell with smaller coverage area moves with the satellite's movement.

[0068] Based on their operating modes, satellites can generally be divided into two types. The first type is transparent mode, also known as relay mode. In this mode, the satellite relays cell information from terrestrial network equipment (such as base stations) or other satellites, primarily relaying signals. Its functions may include radio frequency filtering, frequency conversion, and / or signal amplification. In this mode, the satellite can also be considered a relay, regenerating and forwarding signals, which may involve regenerating and forwarding physical layer signals. The second type is regenerative mode. In this mode, the satellite possesses all or some of the processing functions of a base station.

[0069] Figure 2(a) shows a schematic diagram of an NTN-based communication system architecture provided in an embodiment of this application. In the system architecture shown in Figure 2(a), at least one satellite can operate in a transparent manner. For example, the communication system may include at least a first satellite 201, a second satellite 202, a first terminal device 211, and a first base station 221. Both the first satellite 201 and the second satellite 202 operate in a transparent manner, and both can maintain a connection with the first base station 221. The first terminal device 211 can communicate with the first base station 211 through the first satellite 201 for a certain period of time. The first satellite 201 may have a first cell covering the first terminal device 211. Within this first cell, the first terminal device 211 can receive signals from the first satellite 201. The first terminal device 211 establishes a connection with the first base station 211 through the first cell of the first satellite 201 for communication. This first cell can be the serving cell of the first terminal device, and can be referred to as the first cell of the first satellite 201. In this embodiment, as the first satellite 201 moves and can no longer cover the first cell, the second satellite 202 can provide the same first cell service to the first terminal device 211. The first terminal device 211 can switch from the first satellite 201 to the second satellite 202, that is, the first terminal device 211 can switch from communicating with the first base station 221 via the first satellite 201 to communicating with the first base station 221 via the second satellite 202. Similarly, the second satellite 202 can also act as a relay satellite. The fact that the first satellite 201 and the second satellite 202 have the same cell means that the first base station 221 corresponding to the first cell provided by the first satellite 201 and the first cell provided by the second satellite 202 has not changed. In this case, it can also be considered that the cell covered by the first satellite 201 and the second satellite 202 for the first terminal device 211 is the same cell, that is, the first cell has not changed. For the first terminal device 211, although the satellite providing communication services has changed, the cell covered has not changed. The statement that the cell remains unchanged, or that the same first cell provided by the first satellite 201 and the second satellite 202, can refer to the fact that the physical cell identifier (PCI) of the cell has not changed, and the PCI of the first cell provided by the first satellite 201 and the second satellite 202 remains unchanged. Furthermore, the frequency points of the synchronization signal and physical broadcast signal block (SSB) transmitted in this same cell can also remain unchanged.

[0070] When the second satellite 202 provides coverage of the first cell for the first terminal device 211, the first terminal device 211 communicates with the first base station 211 through the first cell of the second satellite 202. At this time, the first cell is still the serving cell of the first terminal device, and the first cell can also be referred to as the first cell of the second satellite 202. It should be understood that the "neighboring cell" or "neighboring cell of the first cell" in this embodiment refers to the neighboring cell of the serving cell of the terminal device, such as the second cell.

[0071] As shown in Figure 2(a), the communication system may further include a second base station 222 and a second terminal device 212. The second base station 222 provides a serving cell, i.e., a second cell, for the second terminal device 212. This second cell can be considered a neighboring cell of the first cell or a candidate cell for handover by the first terminal device 211. The PCI of the second cell is different from that of the first cell. The second base station 222 and the first base station 221 can be the same base station or different base stations. When the second base station 222 and the first base station 221 are two different base stations, the second base station 222 can communicate with the first base station 221. The second base station 222 can be a satellite or a terrestrial base station; no limitation is made here.

[0072] Figure 2(b) shows another NTN-based communication system architecture provided by an embodiment of this application. In this communication system, at least one satellite can operate in a regenerated form. Exemplarily, the communication system shown in Figure 2(b) includes a first satellite 203 and a second satellite 204, as well as a first terminal device 213. Both the first satellite 203 and the second satellite 204 operate in a regenerated form. Similar to the communication system shown in Figure 2(a), both the first satellite 203 and the second satellite 204 can provide a first cell covering the first terminal device 213. The relationship between the first satellite 203, the second satellite 204, and the first cell can be referred to the description of the relationship between the first satellite 201, the second satellite 202, and the first cell covering the first terminal device 213 in Figure 2(a). The first terminal device 213 communicates directly with either the first satellite 203 or the second satellite 204. Similarly, the first terminal device 213 can communicate with the first satellite 203 for a certain period of time. The first terminal device 213 accesses the first cell through the first satellite 203. This first cell can be called the serving cell of the first terminal device, and it can also be called the first cell of the first satellite 203. As the first satellite 203 moves, it will no longer be able to cover the first cell. At this time, the second satellite 204 can cover the first cell, and the first terminal device 213 can switch from the first satellite 203 to the second satellite 204. After the switch, the first terminal device 213 communicates with the second satellite 204. At this time, the first terminal device 213 accesses the first cell through the second satellite 204, and this first cell remains the serving cell of the first terminal device 213. This first cell can also be called the first cell of the second satellite 204. For the first cell, the PCI of the first cell does not need to change before and after the switch. Similarly, the communication system described in Figure 2(b) may also include a second terminal device 214, a second base station 223, a second cell, etc. The second cell can be considered as a neighboring cell of the first cell, or as a candidate cell for the first terminal device 213 to switch over. This will not be elaborated further here.

[0073] Figure 2(c) shows another NTN-based communication system architecture provided in this application embodiment. In this architecture, the first satellite 205 and the second satellite 206 have some of the processing functions of a base station, such as the DU function, and the first base station 224 deploys the CU function of a base station. The first terminal device 215 communicates with the first base station 224 through the first satellite 205 or the second satellite 206. Similarly, the communication system described in Figure 2(c) may also include a second terminal device 216 and a second base station 225, a first cell, a second cell, etc. The relationship between them can be found in the descriptions of the communication system architecture diagrams in Figures 2(a) and 2(b), which will not be repeated here. In the regeneration working mode, there are regeneration satellites without inter-satellite links, i.e., there is no inter-satellite link (ISL) between satellites; and regeneration satellites with inter-satellite links, i.e., there is an interface between satellites that can directly exchange data, wherein the inter-satellite link is an Xn port.

[0074] Terminal device handover can be divided into two types: hard handover and soft handover. In hard handover, the time periods during which the first and second satellites provide services to the first cell do not overlap. During handover, the first satellite first stops providing services to the terminal device through the first cell, and then the second satellite begins providing services through that first cell. For the terminal device, it first disconnects from the first satellite (e.g., at the moment the first satellite stops providing services), and then reconnects to the second satellite. Link interruptions may occur during the handover. In soft handover, the time periods during which the first and second satellites provide services to the first cell overlap. Before the first satellite stops providing services to the terminal device through the first cell, the second satellite begins providing services through the first cell. For the terminal device, it begins synchronizing with the second satellite before disconnecting from the first satellite, then maintains connections to the cell through both satellites, and finally disconnects from the first satellite. In both of these handover scenarios, when the satellite changes, the base station does not need to send a Layer 3 handover command to the terminal equipment in the first cell. The terminal equipment inherits the radio resource configuration previously configured for it by the base station. These two handover scenarios can also be referred to as satellite switch with re-sync.

[0075] Taking Figure 2(a) as an example, since the first satellite 201 and the second satellite 202 are located at different positions, when the first terminal device 211 soft-switches from the first satellite 201 to the second satellite 202, the signal quality received by the first terminal device 211 from the second satellite 202 may be poor. In this case, if the first terminal device 211 still switches to the second satellite 202, it may cause a wireless link failure between the first terminal device 211 and the second satellite 202. This application provides a communication method that can reduce the probability of wireless link failure caused by the terminal device performing a handover, thereby ensuring communication reliability.

[0076] Figure 3 This is a flowchart illustrating a communication method provided in an embodiment of this application. This embodiment can reduce the probability of wireless link failure due to handover by the terminal device. This embodiment is executed by a terminal device or a module (such as a chip) in the terminal device, a first network device or a module (such as a chip) in the first network device, and a module (such as a chip) in a second network device. The terminal device can correspond to the first terminal device in Figure 2(a), Figure 2(b), or Figure 2(c), the first network device can correspond to the first satellite in Figure 2(a), Figure 2(b), or Figure 2(c), and the second network device can correspond to the second satellite in Figure 2(a), Figure 2(b), or Figure 2(c). The following description uses the execution of this method by the terminal device, the first network device, and the second network device as an example.

[0077] Step 301: The terminal device receives instruction information from the first network device.

[0078] The current state of the terminal device is that it is connected to the first cell via the first network device, where the first cell is referred to as the serving cell of the terminal device. The first network device and the second network device can be the first satellite and the second satellite of the first cell during handover, respectively. That is, the first network device provides service to the first cell for a first period of time, and the second network device provides service to the first cell for a second period of time, with the first and second periods overlapping in time. The PCI of the first cell remains unchanged during the first and second periods of time.

[0079] At this time, the terminal device can receive indication information from the first network device. If the first network device is a transparent relay satellite, then the indication information is sent from the ground base station to the first network device, and then forwarded to the terminal device by the first network device; if the first network device is a regenerable satellite, then the indication information is sent directly to the terminal device by the first network device. It should be understood that this application does not limit the NTN communication architecture of the first network device, the second network device, and the terminal device.

[0080] This instruction information is used to instruct the terminal device to measure the reference signal from the first cell of the second network device.

[0081] Optionally, the first network device may also send an indication message #A to the terminal device, indicating support for a soft handover from the first network device accessing the first cell to the second network device accessing the first cell. For example, the first network device may broadcast an indication message to the terminal device that the first cell supports satellite handover requiring resynchronization, and broadcast a first time and a second time (e.g., before measuring the reference signal from the first cell of the second network device). The first time indicates when the first network device stops providing service to the first cell, and the second time indicates when the second network device begins providing service to the first cell, wherein the second time is less than or equal to the first time, or earlier than or equal to the first time. The terminal device may measure the signal quality of the reference signal between the second time and the first time. Thus, the terminal device can determine when to measure the reference signal of the first cell of the second network device using the received first and second times.

[0082] In one possible implementation of a terminal device receiving indication information from a first network device, the terminal device receives measurement configuration information from the first network device. This measurement configuration information includes the indication information and is used to configure the terminal device to measure a reference signal from a first cell of a second network device. The measurement configuration information also includes a measurement object, which is configured with frequency points and other information for the terminal device to monitor. In this way, the terminal device can obtain the aforementioned indication information by receiving the measurement configuration information without needing to add an additional signaling step, thus saving signaling.

[0083] Optionally, the measurement object can be a measurement object corresponding to the first cell (which, for the terminal device, can also be called a serving cell measurement object. The terminal device obtains the signal quality of the first cell based on this measurement object). The terminal device can measure the reference signal of the first cell from the second network device based on the measurement object corresponding to the first cell. The indication information can be added to the measurement object corresponding to the first cell to instruct the terminal device to measure the reference signal of the first cell from the second network device. Optionally, the measurement object can also be other measurement objects. The network device can add the indication information to other measurement objects to instruct the terminal device to measure the reference signal of the first cell from the second network device. These other measurement objects can be used only to measure the reference signal of the first cell received through the second network device, or they can be used to measure the reference signal of neighboring cells of the first cell. It should be understood that the reference signal of the first cell from the second network device is the same as the reference signal transmitted by the second network device through the first cell, and vice versa; only the expression is different.

[0084] Optionally, the measurement configuration information may include report configuration information, which indicates the criteria for triggering the reporting of measurement reports. Triggering reporting can be divided into event-triggered reporting and periodic-triggered reporting. Event-triggered reporting configuration includes various event categories, threshold values, the duration for which the trigger conditions are met, and the type of reference signal (such as SSB or Channel State Information Reference Signal (CSI-RS)). For example, an A4 event is defined as a neighboring cell's signal quality being better than a threshold value. Typically, the terminal device will not trigger a report immediately after entering the measurement reporting conditions; it must continuously meet the measurement reporting conditions for the specified duration before triggering a report. Periodic-triggered reporting configuration includes the reporting period, reference signal type, and a whitelist of cells. The report configuration information includes this indication information (for example, this indication information is included in the report configuration information for an A4 event, thus instructing the terminal device to consider the first cell from the second network device as a neighboring cell in the A4 event, i.e., to determine whether the signal quality of the first cell from the second network device meets the threshold value for the A4 event). For this reporting configuration, the terminal device will only evaluate whether the event is satisfied or reported in the second and first moments.

[0085] In another possible implementation of the terminal device receiving indication information from the first network device, the indication information may be event-triggered reporting information, which can be used to measure or evaluate the signal quality of the first cell from the second network device. The event-triggered reporting is specifically used to measure or evaluate the signal quality of the first cell specified from the second network device.

[0086] In another possible implementation of the terminal device receiving indication information from the first network device, the indication information can be existing event-triggered reporting information, such as events A1, A2, A3, A4, A5, or A6. When the terminal device performs event measurement or performs measurement reporting evaluation corresponding to the time-triggered reporting information, it considers the first cell of the second network device as a neighboring cell.

[0087] In another possible implementation of the terminal device receiving indication information from the first network device, the terminal device receives other configuration information, which includes the indication information. For example, the other configuration information may be an RRC message or a Medium Access Control (MAC) control element (CE). The indication information can be sent to the terminal device via an RRC message or a MAC CE.

[0088] Step 302: The terminal device receives a reference signal from the first cell of the second network device.

[0089] If the second network device is a transparent relay satellite, then the reference signal is sent from the ground base station to the second network device, and then forwarded by the second network device to the terminal device; if the second network device is a regenerable satellite, then the reference signal is sent directly to the terminal device by the second network device.

[0090] Step 303: The terminal device measures the reference signal from the first cell of the second network device.

[0091] After receiving an instruction from the first network device, the terminal device measures the reference signal of the first cell from the second network device according to the instruction. The terminal device can also measure the reference signal of the first cell from the second network device based on the measurement configuration information received from the first network device.

[0092] As described above, the measurement configuration information may include the measurement object, which includes the synchronization signal and physical broadcast signal block (SSB) frequency, SSB subcarrier spacing, SSB-based measurement timing configuration (SMTC), whitelisted cells, and blacklisted cells, etc. It should be noted that SSB and SMTC can be replaced with other names in this application, and this application is not limited to any particular name. For example, SSB can be referred to as the reference signal, and SMTC can be referred to as the reference signal measurement timing configuration.

[0093] Each cell periodically transmits multiple SSB beams in the time domain (i.e., SSB beam scanning). To ensure accurate measurement of all SSB beams within each cell, the base station, when issuing measurement configuration information, not only indicates the SSB frequencies to be measured but also the time domain location and duration for initiating SSB measurements. This is the time window for the terminal device to search for SSBs, which is configured via the SMTC. Configuring the SMTC effectively instructs the terminal device on the time window for SSB searching, reducing unnecessary measurement power consumption by the terminal device.

[0094] SMTC represents the timing configuration sent by the base station to the terminal device when the terminal device performs SSB-based measurements on the cell. It includes the SMTC period, SMTC duration, and SMTC offset. For example, the SMTC configuration is given by SMTC1, and the configuration information element corresponding to SMTC1 is SSB-MTC, which includes two sub-information elements: periodicityAndOffset and duration.

[0095] periodicityAndOffset represents the SMTC period (characterizing the repetition period of the measurement action, or the period of the SMTC measurement window) and the SMTC offset (used to determine the measurement window, for example, the starting subframe of the time window for the UE to search for the SSB within the period).

[0096] duration indicates the duration of SMTC (characterizing the length of time the measurement action should continue after the measurement action begins).

[0097] The UE typically uses the timing of the current serving cell as a reference to determine the window for the UE to search for the SSB of neighboring cells.

[0098] For example, the UE determines the system frame number (SFN) and subframe number of the current serving cell corresponding to the first subframe of the measurement window according to the following formula.

[0099] SFN mod T = (FLOOR(SMTC bias / 10))

[0100] If the SMTC period exceeds 5 subframes, then subframe = SMTC offset mod 10; otherwise, subframe = SMTC offset or (SMTC offset + 5).

[0101] Where T = CEIL(SMTC cycle / 10). CEIL() is rounded up.

[0102] Optionally, the measurement targets also include whitelisted and blacklisted cells. Network devices can configure specific lists of cells to be measured, namely whitelisted and blacklisted cell lists. For cells included in the blacklist, terminal devices will no longer perform event measurements or report measurements on those cells. Whitelisted cells are those for which terminal devices will perform event measurements and report measurements.

[0103] Optionally, the network device may assign a corresponding measurement object identifier, referred to as MeasObjectId, to each measurement object.

[0104] The terminal device can measure the reference signal according to the specific configuration of the object being measured.

[0105] Optionally, the measurement configuration information may also include measurement quantity configuration information. The measurement quantity configuration information is used to configure the measurement quantities, which may include:

[0106] Reference signal received power (RSRP) reflects the received strength of the reference signal.

[0107] The Received Signal Strength Indicator (RSSI) reflects the total signal strength of the current channel.

[0108] Reference signal received quality (RSRQ) reflects the signal-to-noise ratio and interference level of the current channel quality, and is approximately the ratio of RSRP to RSSI.

[0109] The signal-to-interference-plus-noise ratio (SINR) reflects the signal-to-interference ratio of the current channel and is an important indicator for evaluating terminal equipment.

[0110] Based on the aforementioned measurement configuration information, the terminal device can specify which specific measurement reference signals to measure, providing a foundation for subsequent handover strategies. Generally, the measurement quantities used in handover strategies primarily employ measurement-based RSRP, RSRQ, or SINR as trigger quantities. Specifically, the terminal device performs measurements according to the measurement configuration information. When the terminal device determines that a certain report configuration trigger reporting (including event-triggered reporting or periodic-triggered reporting) is satisfied, the terminal device reports a measurement report. The measurement report content includes at least one of the following: Measurement ID (MeasId), Serving Cell Measurement Result (measResultServingMOList), or Neighboring Cell Measurement Result (measResultNeighCells). The Serving Cell Measurement Result includes the physical cell identifier and cell-level measurement results, such as cell-level RSRP, RSRQ, or SINR measurements. The Serving Cell Measurement Result can also include beam-level measurement results, SSB index or CSI-RS index, and beam-level measurement results, such as beam-level RSRP, RSRQ, or SINR measurements. Neighbor cell measurements include physical cell identifiers, cell-level measurement results of neighboring cells, and may also include beam-level measurement results of neighboring cells.

[0111] When performing measurements, the terminal device can receive first SMTC information and second SMTC information from the first network device (e.g., before measuring the reference signal of the first cell from the second network device). The first SMTC information is used by the terminal device to measure the reference signal of the first cell from the second network device and the reference signal of neighboring cells. The second SMTC information is used to measure the reference signal of either neighboring cells or the reference signal of the first cell from the first network device. The terminal device can measure different reference signals based on the first and second SMTC information. That is, the terminal device can measure the reference signal of the first cell of the second network device and the reference signal of the neighboring cells of the first cell based on the first SMTC information; the terminal device can measure the reference signal of the neighboring cells of the first cell based on the second SMTC information.

[0112] The terminal device can also receive a first time and a second time from the first network device (e.g., before measuring the reference signal of the first cell from the second network device), wherein the first time indicates the time when the first network device stops providing service to the first cell, and the second time indicates the time when the second network device starts providing service to the first cell, wherein the second time is less than or equal to the first time, or the second time is earlier than or equal to the first time. The terminal device begins measuring the reference signal of the first cell from the second network device at some time between the second time and the first time.

[0113] The terminal device can also perform different measurements at different times based on the SMTC information. For example, before the second time point or after the first time point, the terminal device measures the reference signal of the neighboring cells of the first cell based on the second SMTC information; between the second time point and the first time point, the terminal device measures the reference signal of the first cell of the second network device and the reference signal of the neighboring cells of the first cell based on the first SMTC information. As another example, before the second time point, the terminal device measures the reference signal of the neighboring cells and the reference signal from the first cell of the first network device based on the second SMTC information; or before the second time point, the terminal device measures only the reference signal of the neighboring cells based on the second SMTC information. As yet another example, between the second time point and the first time point, the terminal device measures the reference signal of the first cell of the second network device and the reference signal of the neighboring cells based on the first SMTC information; or, between the second time point and the first time point, the terminal device measures the reference signal of the first cell of the second network device, the reference signal of the first cell of the first network device, and the reference signal of the neighboring cells based on the first SMTC information. It should be understood that between the second time and the first time, the terminal device may measure the reference signal from the first cell of the first network device based on the first SMTC information, or it may directly measure the reference signal from the first cell of the first network device without based on the first SMTC information.

[0114] Before measuring the reference signal of the first cell from the second network device, the terminal device may also receive a third SMTC from the first network device, wherein the third SMTC information is used by the terminal device to measure the reference signal of the first cell from the second network device. The terminal device measures only the reference signal of the first cell from the second network device based on the third SMTC information. It should be noted that the third SMTC may not appear simultaneously with the first SMTC. For example, the terminal device may receive both the second and third SMTCs from the first network device. The first network device can configure multiple SMTCs (referred to as SMTC set #1) for the terminal device (for example, four SMTCs can be configured. These four SMTCs have the same period and duration, but different SMTC biases), which are used to measure the reference signals of neighboring cells of the first cell or the reference signal of the first cell. Regarding the third SMTC, in one embodiment, the first network device sends multiple SMTC configurations to the terminal device in the measurement configuration. These multiple SMTC configurations include the second and third SMTCs. The first network device sends indication information #C in the measurement configuration information, indicating which SMTC in the multiple SMTC configurations is the third SMTC. For example, the indication information #C indicates which SMTC configuration among multiple SMTC configurations is the third SMTC. In another implementation, a new SMTC is added in the measurement configuration information for measuring the reference signal from the first cell of the second network device; this SMTC is the third SMTC. Optionally, when the first network device configures the third SMTC for the terminal device, the first network device configures a maximum of three SMTCs in SMTC set #1 for the terminal device to measure the reference signal of the neighboring cells of the first cell or the reference signal of the first cell. Optionally, the terminal device only uses the third SMTC between the second time point and the first time point. When the terminal device switches to the first cell of the second network device, the terminal device does not use the third SMTC to perform measurements.

[0115] Optionally, between the second time point and the first time point, when the terminal device measures the reference signal from the first cell of the second network device, the time deviation between the arrival time of the reference signal from the first cell of the first network device and the reference signal from the first cell of the second network device at the terminal device is dynamically changing due to the high-speed mobility of the first and second network devices. This may lead to an unreasonable SMTC configuration for measuring the reference signal from the first cell of the second network device. Therefore, the network device can configure the terminal device to measure the propagation delay difference between the terminal device and the first and second network devices (for example, the first network device configures the measurement of the propagation delay difference between the terminal device and the first and second network devices via RRC message #1). Further optionally, the network device (e.g., the first network device) notifies the terminal device to report the propagation delay difference between the terminal device and the first and second network devices after the second time point. For example, the first network device carries indication information #E in RRC message #1, instructing the terminal device to report the propagation delay difference between the terminal device and the first and second network devices after the second time point. After the terminal device reports the propagation delay deviation (e.g., propagation delay difference #1) between the terminal device and the first network device and the second network device to the first network device, when the terminal device detects that the latest propagation delay deviation (e.g., propagation delay difference #2) between the terminal device and the first network device and the second network device exceeds a certain threshold (e.g., the first network device configures this threshold in RRC message #1), the terminal device reports the latest propagation delay deviation (e.g., propagation delay difference #2) between the terminal device and the first network device and the second network device to the first network device.

[0116] Between the second and first time points, after obtaining the reference signal quality from the first cell of the second network device and the reference signal quality from the first cell of the first network device, the terminal device maintains the measured reference signal quality from the first cell of the second network device and the reference signal quality from the first cell of the first network device, respectively, between the second and first time points. For example, the reference signal measurement output is divided into beam-level measurement results (also called reference signal-level measurement results, such as the measurement results corresponding to SSB) and cell-level measurement results. After physical layer filtering, the beam-level measurement results are obtained and input to the radio resource control (RRC) layer for further processing. On one hand, the RRC layer performs beam combining to obtain cell-level measurement results, and then filters the cell-level measurement results to obtain the final reference signal quality used for reporting. On the other hand, after filtering, the RRC layer can perform beam selection and report the selected beam to the network. The terminal device maintains the measured reference signal quality from the first cell of the second network device and the reference signal quality from the first cell of the first network device, respectively, between the second and first time points. The terminal device performs physical layer filtering on the reference signal quality of the first cell from the first network device and the reference signal quality of the first cell from the second network device to obtain beam-level measurement results. Then, the beam-level reference signal quality of the first cell from the first network device and the reference signal quality of the first cell from the second network device are respectively input to the RRC layer for filtering and beam combining to obtain the cell-level reference signal quality of the first cell from the first network device and the reference signal quality of the first cell from the second network device. These cell-level reference signal quality data can be reported to the network. Optionally, the terminal device can also perform beam selection after filtering in the RRC layer, reporting the selected reference signal beam from the first cell of the second network device or the reference signal beam from the first cell of the first network device to the network.

[0117] Optionally, if the terminal device determines that the reference signal quality from the first cell of the second network device is relatively poor (for example, when the reference signal quality from the first cell of the second network device is below a first threshold), the terminal device will not perform a soft handover. That is, for the terminal device, it needs to wait for the handover configuration or handover command sent by the first network device, or wait for the execution conditions of the conditional handover sent by the first network device to be met before it will hand over to a neighboring cell (such as the second cell).

[0118] Optionally, when the terminal device determines that the reference signal quality of the first cell from the second network device is relatively good (for example, when the reference signal quality of the first cell from the second network device is higher than a first threshold), the terminal device performs a soft handover.

[0119] Step 304: The terminal device sends the reference signal quality of the first cell from the second network device to the first network device.

[0120] The terminal device can trigger a measurement report by sending measured reference signal quality data to the first network device, based on a standard. For example, measurement configuration information may include report configuration information, which specifies the standard for triggering the measurement report. Triggered reporting can be divided into event-triggered reporting and periodic-triggered reporting. Event-triggered reporting configuration includes various event categories, threshold values, the duration for which the trigger condition is met, and the type of reference signal (such as SSB or Channel State Information Reference Signal (CSI-RS)). Typically, the terminal device will not trigger a report immediately after entering the measurement reporting condition; it must continuously meet the reporting conditions for the specified duration before triggering the report. Periodic-triggered reporting configuration includes the reporting period, reference signal type, and a whitelist of cells. The terminal device will perform the corresponding measurements according to the configuration and send measurement reports according to the reporting period and interval. For each report configuration, the network device will assign a corresponding report configuration identifier (ReportConfigId).

[0121] The network side can configure multiple measurement configuration information. For example, the measurement configuration information also includes a measurement identifier (ID). The measurement ID is used to link the measurement object with the measurement configuration as a set, as shown below.

[0122]

[0123] The measurement ID (measId) links the measurement object identifier (MeasObjectId) and the measurement report configuration identifier (reportConfigId), thus linking the measurement object and the measurement report configuration. When a terminal device sends a measurement report to a network device, it indicates the measId to the network device. The network device can then use the measId to find the corresponding measObjectId and reportConfigId, and determine what event the received measurement report pertains to. The network device can also configure multiple measIds to link multiple measurement objects to the same measurement report configuration, or vice versa. For example, a measurement report sent by a terminal device to a first network device might carry measurements of the reference signal quality of a first cell from a second network device.

[0124] Optionally, the report configuration information of the measurement configuration information may include the indication information in step 301. The terminal device measures the reference signal received from the first cell from the second network device according to the measurement configuration corresponding to the measurement object associated with the report configuration, and reports the measurement results according to the report configuration information. After the terminal device reports the reference signal quality to the first network device, the first network device will perform subsequent processing according to the handover strategy. For example, the first network device can determine whether it needs to hand over the terminal device to a neighboring cell (such as the second cell) based on the quality of the reference signal received from the first cell of the second network device. If the reference signal quality from the first cell of the second network device is poor, for example, below a certain threshold, the first network device will configure a handover configuration or handover command for the terminal device to hand over to the neighboring cell (such as the second cell). If the reference signal quality from the first cell of the second network device is good, for example, not below a certain threshold, the first network device does not need to configure a handover configuration or handover command for the terminal device to hand over to the neighboring cell (such as the second cell), and the terminal device will hand over to access the first cell through the second network device (i.e., perform a soft handover from the first network device to the second network device).

[0125] The first network device can also send the reference signal quality received from the second network device's first cell to the third network device, which will then determine whether the terminal device needs to be handed over to a neighboring cell (such as the second cell). If the reference signal quality from the second network device's first cell is poor, for example, below a certain threshold, the third network device will configure a handover configuration or handover command for the terminal device to hand over to a neighboring cell (such as the second cell). If the reference signal quality from the second network device's first cell is good, for example, not below a certain threshold, the third network device does not need to configure a handover configuration or handover command for the terminal device to hand over to a neighboring cell (such as the second cell), and the terminal device will switch to accessing the first cell through the second network device (i.e., perform a soft handover from the first network device to the second network device).

[0126] Optionally, when the terminal device reports the measurement results according to the report configuration information, it may carry the reference signal quality of the first cell from the second network device in the neighbor cell measurement results (e.g., measResultNeighCells), or add an indication information #F to the reference signal quality of the first cell of the second network device in the protocol to indicate the reference signal quality of the first cell from the second network device.

[0127] Optionally, in step 305, the terminal device receives first condition information from the first network device.

[0128] The first condition information includes the radio resource configuration information of the first candidate cell (such as the second cell) and the execution conditions for handover to the first candidate cell.

[0129] The measurement configuration information corresponding to the first condition information can be found in the descriptions in steps 301 to 304.

[0130] Optionally, when the first conditional handover is time-based, the time range [T1, T2] in the time-based conditional handover can include the time range between the second time point and the first time point. For example, T1 is the same as the second time point, and T2 is the same as the first time point. The terminal device can measure the reference signal of the first cell received from the second network device within the time period [T1, T2]. Outside the time period [T1, T2], it is not necessary to measure the reference signal of the first cell received from the second network device.

[0131] Optionally, the [T1,T2] configured for different terminal devices can be different for the first network device or the third network device. For example, different terminal devices can access the first cell through the second network device at different time periods.

[0132] The terminal device evaluates whether the execution conditions for handing over to the first candidate cell are met. When the execution conditions are met, the terminal device performs the condition handover, that is, hands over to the first candidate cell (using the radio resource configuration information of the first candidate cell and accessing the first candidate cell).

[0133] Optionally, in step 306, the terminal device receives second condition information from the first network device.

[0134] The second condition information is used to instruct the terminal device to perform conditional handover of the first candidate cell according to the first condition information when the measured reference signal quality from the first cell of the second network device is lower than the first threshold.

[0135] Optionally, the second condition information may be included in the first condition information in step 305. For example, the second condition information may be that the serving cell signal quality is lower than a first threshold in the event reporting condition of the first condition information. The measurement configuration information corresponding to the execution condition or the first condition information may carry indication information #B, indicating that the event reporting condition in the first condition handover refers to the first cell signal quality received through the second network device being lower than the first threshold.

[0136] For example, the terminal device determines whether the reference signal quality of the first cell from the second network device is lower than a first threshold according to the instruction of the second condition information. When the reference signal quality of the first cell from the second network device is lower than the first threshold, the terminal device performs conditional handover of the first candidate cell according to the received first condition information. If the execution conditions of the first condition information are met, the terminal device switches to the first candidate cell.

[0137] It should be noted that this application does not limit the order in which the terminal device measures whether the reference signal quality of the first cell from the second network device is lower than a first threshold and whether the terminal device evaluates whether the execution conditions for handover to the first candidate cell are met. In one implementation, the terminal device only initiates the evaluation of whether the execution conditions for handover to the first candidate cell are met when the reference signal quality of the first cell from the second network device is lower than the first threshold. When the execution conditions for handover to the first candidate cell are met, the terminal device performs the conditional handover, i.e., handing over to the first candidate cell (using the radio resource configuration information of the first candidate cell and accessing the first candidate cell). In another implementation, the terminal device only initiates the evaluation of whether the reference signal quality of the first cell from the second network device is lower than the first threshold when the execution conditions of the first condition information are met. When the reference signal quality of the first cell from the second network device is lower than the first threshold, the terminal device performs the conditional handover, i.e., handing over to the first candidate cell (using the radio resource configuration information of the first candidate cell and accessing the first candidate cell). In another implementation, when the terminal device receives the first condition information, it initiates an evaluation to determine whether the execution conditions for handover to the first candidate cell are met. When the terminal device receives the second condition information, it evaluates whether the reference signal quality of the first cell from the second network device is lower than a first threshold. When both conditions are met, the terminal device performs the condition handover, that is, hands over to the first candidate cell (using the radio resource configuration information of the first candidate cell and accessing the first candidate cell).

[0138] Optionally, when performing steps 305 and 306, step 304 is optional.

[0139] In this embodiment of the application, based on Figure 3In the method of this embodiment, the terminal device measures the quality of the first cell reference signal from the second network device according to the indication information, and sends the reference signal quality to the network device. Based on the reference signal quality, the probability of radio link failure due to handover by the terminal device can be reduced. Furthermore, according to the above scheme, after receiving the reference signal, the network device can determine the handover strategy of the terminal device based on the quality of the reference signal. For example, if the network device determines that the quality of the reference signal is poor, it can instruct the terminal device not to continue handover to access the first cell through the second network device, or it can instruct the terminal device to handover to another cell with a better signal, such as a neighboring cell of the first cell (the second cell).

[0140] Figure 4(a) is a flowchart illustrating another communication method provided in an embodiment of this application. This embodiment is executed by a terminal device or a module (such as a chip) in the terminal device, and a first network device or a module (such as a chip) in the first network device. The following description uses the terminal device, the first network device, and the second network device executing the method as an example.

[0141] The method includes the following steps:

[0142] Step 401a: The terminal device receives the first time and the second time from the first network device.

[0143] The first timeframe indicates the time when the first network device stops providing service to the first cell, and the second timeframe indicates the time when the second network device begins providing service to the first cell, wherein the second timeframe is less than or equal to the first timeframe. The relationship between the first cell, the first network device, and the second network device can be found in [reference needed]. Figure 3 The description of the embodiments will not be repeated here.

[0144] and Figure 3 Unlike the previous embodiment, in this embodiment, the terminal device is a terminal device in the first cell that is in a deactivated or idle state, and the first network device and the second network device simultaneously provide coverage services for the first cell.

[0145] For a terminal device camped on the first cell via the first network device, it can initiate measurement of the reference signal transmitted via the second network device at some time between the second time and the first time. When the reference signal transmitted via the second network device is better than the second threshold, the terminal device can switch to camping on the first cell via the second network device. Optionally, the first network device can send the value of the second threshold to the terminal device via a broadcast message.

[0146] Step 402a: The terminal device receives the second instruction information.

[0147] Optionally, the second indication information is used to instruct the terminal device not to access or camp on the first cell through the second network device between the second time and the first time.

[0148] Optionally, the second indication information is used to indicate that the second network device is the target network device of the first cell. Between the second time and the first time, the terminal device does not access or camp on the first cell through the second network device.

[0149] The terminal device can receive the second indication information through the first network device. Optionally, when the terminal device is camped on the first cell through the first network device, the terminal device will not switch to camping on the first cell through the second network device between the second time and the first time, but will instead choose to access the first cell through the first network device. In this case, the terminal device can receive the first time and the second time through the first network device.

[0150] Optionally, the terminal device can also receive the second indication information through a second network device. The second network device can send the second indication information to the terminal device via broadcast. The second network device can also broadcast information from the first network device, such as the ephemeris information of the first network device, the reference signal configuration corresponding to the first network device (e.g., the index of the reference signal), etc. When the terminal device is powered on within the coverage area of ​​the first cell, and the terminal device receives the signal from the second network device, in this case, according to the second indication information, the terminal device will not access the first cell through the second network device between the second and first time points, but will instead choose to access the first cell through the first network device.

[0151] In one possible implementation, a third network device provides service to a second cell, which is a neighboring cell of the first cell. The third network device sends third indication information to terminal devices in the second cell. This third indication information indicates that the first cell will provide service through both the first and second network devices simultaneously between the second and first time points, or that both the first and second network devices will simultaneously provide service to the first cell between the second and first time points. The third indication information includes both the second and first time points. Terminal devices camped in the second cell will not camp on the first cell through the second network device between the second and first time points. Optionally, the third indication information is further used to indicate the ephemeris information and / or reference signal configuration (e.g., reference signal index) of the first cell corresponding to the first network device, or to indicate the ephemeris information and / or reference signal configuration (e.g., reference signal index) of the first cell corresponding to the second network device, so that the terminal device residing in the second cell can know which reference signals of the first cell are transmitted by the first network device and which reference signals of the first cell are transmitted by the second network device according to the reference signal configuration of the first cell corresponding to the first network device or the reference signal configuration of the first cell corresponding to the second network device, so that the terminal device residing in the second cell can know whether the reference signal of the first cell received is transmitted by the first network device.

[0152] Step 403a: Based on the second indication information, the terminal device determines that it will not access or camp on the first cell through the second network device between the second time and the first time.

[0153] Optionally, the terminal device in the first cell determines, based on the second indication information, to access the first cell through the first network device between the second time and the first time.

[0154] Optionally, for the idle or inactive terminal device in the second cell (the terminal device in the second cell can also be in a connected state), before the second time point, only the reference signal transmitted by the first cell through the first network device is measured; after the first time point, only the reference signal transmitted by the first cell through the second network device is measured; between the second time point and the first time point, both the reference signals transmitted by the first cell through the first network device and the reference signals transmitted by the first cell through the second network device are measured simultaneously; or between the second time point and the first time point, only the reference signal transmitted by the first cell through the first network device is measured. This ensures that when two network devices in the first cell are providing services simultaneously, the terminal device in the second cell measures the reference information of neighboring cells through the corresponding network devices at different time periods, thereby enabling more accurate neighboring cell measurements.

[0155] In this embodiment of the application, the method based on the embodiment of FIG4(a) can ensure that the terminal devices in the first cell between the second time and the first time are all accessed or camped in the first cell through the first network device, thereby avoiding interference between terminal devices in the same cell caused by some terminal devices accessing or camping in the first cell through the first network device and some terminal devices accessing or camping in the first cell through the second network device.

[0156] It is understood that, in order to achieve the functions in the above embodiments, the terminal device or the first network device includes hardware structures and / or software modules corresponding to perform each function. Those skilled in the art should readily recognize that, based on the units and method steps of the various examples described in conjunction with the embodiments disclosed in this application, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware depends on the specific application scenario and design constraints of the technical solution.

[0157] Figure 4(b) is a flowchart illustrating another communication method provided in an embodiment of this application. This embodiment is executed by a terminal device or a module (such as a chip) in the terminal device, a first network device or a module (such as a chip) in the first network device, and a second network device or a module (such as a chip) in the second network device. The following description uses the terminal device, the first network device, and the second network device executing the method as an example.

[0158] The method includes the following steps:

[0159] Step 401b: The terminal device receives the first moment from the first network device.

[0160] Optionally, the terminal device may also receive a second moment from the first network device.

[0161] The relationship between the first moment, the second moment, the first cell, the first network device, and the second network device can be found in [reference needed]. Figure 3 The description of the embodiments will not be repeated here. The terminal device may be in a connected state, a deactivated state, or an idle state; the state of the terminal device is not limited here.

[0162] Optionally, the first and second time points can be carried in the system information (e.g., system information 19) from the first network device. The terminal device receives the system information from the first network device to obtain the first and second time points. This system information may also carry auxiliary information corresponding to the second network device. The auxiliary information may include ephemeris information, the epoch time of the ephemeris information, the effective length of the ephemeris information, etc. Optionally, this system information may also carry indication information #D, indicating support for satellite handover requiring resynchronization (i.e., when the satellite changes but the cell's PCI remains unchanged, the first network device supports handover without sending a Layer 3 handover command to the terminal device in that first cell). Optionally, the indication information #D may also include auxiliary information corresponding to the second network device.

[0163] The epoch time of the ephemeris information corresponding to the second network device indicates the system frame number and subframe number. That is, the ephemeris information of the second network device refers to the location of the second network device at that epoch time. The terminal device can calculate the current location of the second network device based on the location of the second network device corresponding to that epoch time. The system frame number indicated in the epoch time indicates the current system frame or the next system frame when the terminal device receives the system information, or the system frame number indicated in the epoch time indicates the system frame most recent to the time when the terminal device receives the system information.

[0164] Optionally, the system information sent by the first network device may also include auxiliary information corresponding to the neighboring cells of the first cell of the second network device.

[0165] Ephemeris information, also known as orbit information, refers to the operational path information of non-terrestrial network devices associated with the cell, and can also be referred to as the ephemeris information of the non-terrestrial network devices associated with the cell. The determination of ephemeris information can be shown in Figure 4(c) or Figure 4(d), where Figure 4(c) is a schematic diagram of orbit information represented using Kepler orbit format according to an embodiment of this application, and Figure 4(d) is a schematic diagram of orbit information represented using state vectors according to an embodiment of this application.

[0166] The parameters shown in Figure 4(c) include orbital-level parameters, such as i0 being the inclination, Ω0 being the longitude of the ascending node, and ω being the perigee angular distance. These orbital-level parameters are used to determine the orbit. The parameters shown in Figure 4(d) include satellite-level parameters used to determine the satellite's position, such as M0 as the mean perigee angle at epoch time.

[0167] When orbital information is represented using a state vector, the velocity vector in the state vector, such as (v... x ,v y ,v zFor non-synchronous satellites, velocity and reference point information are required. The position coordinate system based on the state vector can be a latitude, longitude, and altitude coordinate system (λ, ψ, h) or a geocentric coordinate system (X, X, Z) as shown in Figure 4(d), etc. The embodiments of this application do not limit this.

[0168] Step 402b: The terminal device synchronizes with the first cell through the second network device.

[0169] For hard handover, the terminal device begins downlink synchronization with the first cell via the second network device at the first moment. For soft handover, the terminal device performs downlink synchronization with the first cell via the second network device between the second moment and the first moment (e.g., after any moment between the second moment and the first moment).

[0170] The terminal device starts a timer #1 at the subframe time indicated by the epoch time of the ephemeris information of the second network device received from the system information of the first network device. The length of the timer is the effective length of the ephemeris information of the second network device received from the system information of the first network device.

[0171] Step 403b: The terminal device receives system information from the second network device.

[0172] The terminal device acquires system information (e.g., system information 19) from the second network device. Optionally, the terminal device acquires the system information of the second network device after performing downlink synchronization with the first cell via the second network device. For example, the terminal device can acquire the system information of the second network device without waiting for timer #1 to time out after performing downlink synchronization with the first cell via the second network device, or the terminal device can acquire the system information of the second network device after performing downlink synchronization with the first cell via the second network device and waiting for timer #1 to time out. The system information sent by the second network device includes corresponding auxiliary information in the second network device. When the terminal device acquires the system information sent by the second network device, the terminal device starts or restarts timer #1 at the subframe time indicated by the epoch time of the ephemeris information of the second network device received from the system information of the second network device. The length of this timer is the effective length of the ephemeris information of the second network device received from the system information of the second network device.

[0173] The terminal device initiates a random access procedure in the first cell of the second network device, or the terminal device does not need to initiate a random access procedure in the first cell of the second network device and directly transmits data (i.e., the terminal device transmits and receives data according to the pre-configured authorization sent by the first network device or the terminal device listens to the downlink physical control channel sent by the second network device to obtain authorization to transmit and receive data).

[0174] Optionally, if the terminal device obtains the system information of the second network device in step 403b, the terminal device may use the auxiliary information corresponding to the neighboring cells of the first cell in the second network device obtained in step 401b to perform the measurement of the neighboring cells of the first cell.

[0175] It should be noted that this application does not limit the order in which uplink and downlink synchronization, starting the timer, and obtaining system information from the second network device are performed.

[0176] In this embodiment, the method based on the embodiment of Figure 4(b) ensures that after the terminal device synchronizes with the first cell through the second network device, it can promptly obtain the ephemeris information of the second network device sent by the second network device, thus guaranteeing the handover performance of the terminal device. Furthermore, the terminal device can promptly obtain the ephemeris information of the neighboring cells of the first cell of the second network device, thereby enabling timely measurement of the neighboring cells of the first cell and ensuring the handover performance of the terminal device. Additionally, by promptly obtaining the ephemeris information of the second network device, the terminal device can maintain the ephemeris information of the second network device using the system frame number and subframe number of the first cell in the second network device, reducing the complexity of the terminal device.

[0177] Figure 5 and Figure 6 The diagram illustrates the possible structures of communication devices provided in the embodiments of this application. These communication devices can be used to implement the functions of the terminal device or the first network device in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments. In the embodiments of this application, the communication device can be a terminal device or a first network device, or it can be a module (such as a chip) applied to the terminal device or the first network device.

[0178] Figure 5 The communication device 500 shown includes a processing unit 510 and a transceiver unit 520. The communication device 500 is used to implement the above-described... Figure 3 The functions of the terminal device or the first network device in the method embodiment shown in Figure 4(a) or Figure 4(b).

[0179] When the communication device is used to implement the functions of the terminal device in the above method embodiment, the transceiver unit 520 is used to receive indication information from the first network device, the terminal device accesses the first cell through the first network device, the indication information is used to instruct the terminal device to measure the reference signal of the first cell from the second network device, the transceiver unit 520 is also used to receive the reference signal of the first cell from the second network device, and send the signal quality of the reference signal of the first cell of the second network device to the first network device; the processing unit 510 is used to measure the reference signal of the first cell of the second network device.

[0180] In one possible implementation, the transceiver unit 520 is further configured to receive a first time and a second time from the first network device, wherein the first time indicates the time when the first network device stops providing services to the first cell, and the second time indicates the time when the second network device starts providing services to the first cell, wherein the second time is earlier than or equal to the first time; the processing unit 510 is further configured to switch from accessing the first cell through the first network device to accessing the first cell through the second network device at a third time, wherein the third time is between the second time and the first time.

[0181] In one possible implementation, the transceiver unit 520 is further configured to receive measurement configuration information from the first network device. The measurement configuration information includes the aforementioned indication information. The measurement configuration information is used to configure the measurement reference signal of the terminal device. The measurement configuration information includes the measurement object and report configuration information, wherein the measurement object is the measurement object corresponding to the first cell.

[0182] In one possible implementation, the transceiver unit 520 is further configured to receive first SMTC information and second SMTC information from the first network device, wherein the first SMTC information is used to measure the reference signal of the first cell of the second network device and the reference signal of the neighboring cells of the first cell, and the second SMTC information is used to measure the reference signal of the neighboring cells of the first cell.

[0183] In one possible implementation, the transceiver unit 520 is further configured to receive first condition information from the first network device, the first condition information including radio resource configuration information of the first candidate cell and execution conditions for handover to the first candidate cell; the transceiver unit 520 is further configured to receive second condition information from the first network device, the second condition information being used to indicate that when the signal quality of the reference signal of the first cell of the second network device is lower than a first threshold, condition handover of the first candidate cell is performed.

[0184] In one possible implementation, the processing unit 510 is further configured to measure the reference signal of the neighboring cells of the first cell based on the second SMTC information before the second time or after the first time; and to measure the reference signal of the first cell of the second network device and the reference signal of the neighboring cells of the first cell based on the first SMTC information between the second time and the first time.

[0185] In one possible implementation, the processing unit 510 is further configured to measure the signal quality of the first cell from the second network device between the second time and the first time, and to measure the signal quality of the first cell from the first network device between the second time and the first time.

[0186] In one possible implementation, the processing unit 510 is further configured to maintain the signal quality of the first cell of the second network device and the signal quality of the first cell of the first network device respectively between the second time and the first time.

[0187] When the communication device 500 is used to implement the function of the first network device in the above method embodiment, the transceiver unit 520 is used to send instruction information to the terminal device. The instruction information is used to instruct the terminal device to measure the reference signal from the first cell of the second network device. The first cell is the cell that the terminal device accesses through the first network device. The transceiver unit 520 is also used to receive the signal quality of the reference signal from the terminal device.

[0188] In one possible implementation, the transceiver unit 520 is further configured to send a first time and a second time to the terminal device. The first time indicates the time when the first network device stops providing services to the first cell, and the second time indicates the time when the second network device starts providing services to the first cell, wherein the second time is less than or equal to the first time; and a third time is between the second time and the first time, wherein the third time is the time when the terminal device switches from accessing the first cell through the first network device to accessing the first cell through the second network device.

[0189] In one possible implementation, the transceiver unit 520 is further configured to send measurement configuration information to the terminal device. The measurement configuration information includes indication information and is used to configure the measurement reference signal of the terminal device. The measurement configuration information includes a measurement object and report configuration information, wherein the measurement object is the measurement object corresponding to the first cell.

[0190] In one possible implementation, the transceiver unit 520 is further configured to send first SMTC information and second SMTC information to the terminal device, wherein the first SMTC information is used to measure the reference signal of the first cell of the second network device and the reference signal of the neighboring cell, and the second SMTC configuration information is used to measure the reference signal of the neighboring cell.

[0191] In one possible implementation, the transceiver unit 520 is further configured to send first condition information to the terminal device, the first condition information including radio resource configuration information of the first candidate cell and execution conditions for switching to the first candidate cell; the transceiver unit 520 is further configured to send second condition information to the terminal device, the second condition information being used to indicate that when the signal quality of the reference signal of the first cell of the second network device is lower than a first threshold, conditional switching of the first candidate cell is performed.

[0192] For a more detailed description of the processing unit 510 and the transceiver unit 520, please refer directly to the relevant descriptions in the above method embodiments, which will not be repeated here.

[0193] Figure 6 The communication device 600 shown includes a processor 610 and an interface circuit 620. The processor 610 and the interface circuit 620 are coupled to each other. It is understood that the interface circuit 620 can be a transceiver or an input / output interface. Optionally, the communication device 600 may also include a memory 630 for storing instructions executed by the processor 610, or storing input data required by the processor 610 to execute instructions, or storing data generated after the processor 610 executes instructions.

[0194] When the communication device 600 is used to implement the above method embodiment, the processor 610 is used to implement the function of the processing unit 510, and the interface circuit 620 is used to implement the function of the transceiver unit 520.

[0195] It is understood that the processor in the embodiments of this application may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor may be a microprocessor or any conventional processor.

[0196] The method steps in the embodiments of this application can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disks, portable hard disks, compact disc read-only memory (CD-ROM), or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Additionally, the ASIC can reside in a terminal device or network device. Alternatively, the processor and storage medium can exist as discrete components in an access network device or terminal.

[0197] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer programs or instructions. A computer program is a set of instructions that directs each step of an action of an electronic computer or other device with message processing capabilities. It is typically written in a programming language and runs on a target architecture. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are performed, in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center integrating one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video optical disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium can be volatile or non-volatile, or it can include both types of storage media.

[0198] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0199] In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates an "or" relationship between the preceding and following related objects; in the formulas of this application, the character " / " indicates a "division" relationship between the preceding and following related objects.

[0200] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply the order of execution; the execution order of each process should be determined by its function and internal logic.

Claims

1. A communication method, characterized in that, include: Receive a first moment and / or a second moment from a first network device, wherein the first moment indicates the moment when the first network device stops providing services to the first cell, and the second moment indicates the moment when the second network device starts providing services to the first cell; At the first moment, or between the second moment and the first moment, downlink synchronization is performed with the first cell via the second network device; After downlink synchronization with the first cell via the second network device, system information is received from the second network device; wherein, the system information includes indication information, which is used to indicate support for satellite handover that requires resynchronization; Start or restart the timer, wherein the length of the timer is the effective length of the ephemeris information in the system information received from the second network device; The start or restart timer includes: The timer is started or restarted from the first subframe time, which is indicated by the epoch time of the ephemeris information of the second network device, and the epoch time of the ephemeris information of the second network device is obtained from the system information of the second network device.

2. The method according to claim 1, characterized in that, The method further includes: The timer is started at the second subframe time, which is indicated by the epoch time of the ephemeris information of the second network device in the system information of the first network device. The length of the timer is the effective length of the ephemeris information of the second network device received from the system information received from the first network device.

3. The method according to claim 1 or 2, characterized in that, The first network device is a first satellite device, and the second network device is a second satellite device.

4. The method as described in claim 1 or 2, characterized in that, The system information includes system information 19.

5. A communication method, characterized in that, include: Send a first time and / or a second time to the terminal device, wherein the first time indicates the time when the first network device stops providing services to the first cell, and the second time indicates the time when the second network device starts providing services to the first cell; The first moment is used for the terminal device to perform downlink synchronization with the first cell through the second network device, and to obtain system information of the second network after the downlink synchronization; wherein, the system information includes indication information, which is used to indicate that satellite handover that requires resynchronization is supported; the system information is used for the terminal device to start or restart a timer, wherein the length of the timer is the effective length of the ephemeris information in the system information received from the second network device; The start or restart timer includes: starting or restarting the timer from the first subframe time, wherein the first subframe time is indicated by the epoch time of the ephemeris information of the second network device, and the epoch time of the ephemeris information of the second network device is obtained from the system information of the second network device; Before the first moment, provide services to the terminal devices in the first cell.

6. The method as described in claim 5, characterized in that, The system information includes system information 19.

7. The method as described in claim 5 or 6, characterized in that, The system information includes the effective length of the ephemeris information of the second network device.

8. The method according to claim 5 or 6, characterized in that, The first network device is a first satellite device, and the second network device is a second satellite device.

9. A communication device, characterized in that, Includes a module for performing the method of any one of claims 1 to 4, or the method of any one of claims 5 to 8.

10. A communication device, characterized in that, Includes a processor; when the communication device is in operation, the processor executes computer instructions to perform the method of any one of claims 1 to 4, or the method of any one of claims 5 to 8.

11. A communication device, characterized in that, It includes a processor and an interface circuit, the processor being configured to communicate with other devices via the interface circuit and to perform the method of any one of claims 1 to 4, or to perform the method of any one of claims 5 to 8.

12. A computer program product, characterized in that, The computer program product includes instructions that, when executed on a processor, cause the processor to perform the method of any one of claims 1 to 4, or the method of any one of claims 5 to 8.

13. A computer-readable storage medium, characterized in that, The storage medium stores a computer program or instructions, which, when executed by a communication device, implement the method described in any one of claims 1 to 4, or the method described in any one of claims 5 to 8.

14. A communication system, characterized in that, It includes a terminal device for performing the method of any one of claims 1 to 4, and a network device for performing the method of any one of claims 5 to 8.

Images