Communication method and communication device

Abstract

The invention provides a communication method and a communication device. The method comprises: a terminal device receiving indication information of a first network device, the terminal device being a terminal device accessed through a first cell of the first network device, the indication information being used for indicating the terminal device to measure a reference signal sent by a second network device through the first cell, and the terminal device receives a reference signal sent by the second network device through the first cell, and the terminal device measures the signal quality of the reference signal based on the indication information and sends the signal quality of the reference signal to the first network device. According to the scheme, the wireless link failure probability caused by switching execution of the terminal equipment can be reduced.

Description

Technical Field

[0001] This application relates to the field of communication technologies, and in particular, to a communication method and a communication device. Background Art

[0002] A non-terrestrial network (NTN) is a communication achieved by means of non-ground network devices. Non-ground network devices include aerial network devices such as satellites, unmanned aerial vehicles, and high altitude platform station (HAPS) communication systems. NTN has the advantages of wide coverage, long communication distance, high reliability, great flexibility, high throughput, etc., and is not affected by geographical environment, climate conditions, and natural disasters. It has been widely used in fields such as aviation communication, maritime communication, and military communication. Introducing NTN into the fifth generation (5G) mobile network and subsequent evolved system architectures such as the sixth generation (6G) system can greatly improve the user experience. On the one hand, the NTN network can enhance the reliability of communication, such as providing more stable communication services for users in high-speed mobile scenarios such as trains and airplanes; on the other hand, the NTN network can also provide a larger coverage area, such as providing communication services for users in the sea and desert; in addition, the NTN network can also provide more data transmission resources to support a larger number of connections. Therefore, the status of NTN will be further improved in the future.

[0003] After NTN is introduced into the 5G mobile network and subsequent evolved system architectures, the handover technology of terminal devices needs to be further studied. Summary of the Invention

[0004] Embodiments of this application provide a communication method and a communication device for reducing the probability of radio link failure caused by a terminal device performing a handover.

[0005] In a first aspect, an embodiment of the present application provides a communication method. This method can be executed by a terminal device or a module (such as a chip) in the terminal device. The terminal device is a terminal device accessing a first cell of a first network device. The method includes: receiving indication information from the first network device, where the indication information is used to instruct the terminal device to measure a reference signal sent by a second network device through the first cell, and receiving the reference signal of the first cell from the second network device. After receiving the reference signal, measure the signal quality of the reference signal and send the signal quality of the reference signal to the first network device. In this solution, the terminal device accesses the first cell through the first network device, measures the quality of the reference signal sent by the second network device through the first cell according to the indication information of the first network device, and sends the reference signal quality to the network device, so that it is possible to avoid handover failures or reduced link quality after handover caused by performing handover without knowing the signal quality of the second network device, and the probability of radio link failure caused by the terminal device performing handover can be reduced. Further, according to the above solution, after the network device receives the reference signal, it can determine the handover strategy of the terminal device according to 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 to handover to access the first cell through the second network device, or it can also instruct the terminal device to handover to other cells with good signals, such as neighboring cells of the first cell.

[0006] In a possible implementation method, the terminal device receives a first time and a second time from the first network device. The first time indicates the time when the first network device stops providing services for the first cell, and the second time indicates the time when the second network device starts providing services for the first cell, where the second time is less than or equal to the first time. The terminal device measures the signal quality of the reference signal between the second time and the first time. In this solution, the terminal device can determine when to measure the reference signal of the first cell of the second network device based on the received first time and second time.

[0007] In a possible implementation method, the receiving the indication information from the first network device includes: the terminal device receives measurement configuration information from the first network device. The measurement configuration information contains the above indication information, and the measurement configuration information is used to configure the terminal device to measure the reference signal. In this solution, the terminal device can obtain the above indication information by receiving the measurement configuration information without additional signaling to receive the indication information, thereby saving system signaling overhead and the complexity of terminal device processing.

[0008] In a possible implementation method, the measurement configuration information further includes a measurement object and reporting configuration information, where the measurement object is the measurement object corresponding to the first cell. In this solution, the terminal device can clearly perform measurements according to the measurement object corresponding to the first cell.

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

[0010] In a possible implementation method, 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, including: 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 between the second moment and the first moment.

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

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

[0013] In a possible implementation method, the terminal device respectively maintains 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 measured between the second moment and the first moment.

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

[0015] In a possible implementation method, the terminal device switches from accessing the first cell through the first network device to accessing the first cell through the second network device at a third moment, and the third moment is between the second moment and the first moment.

[0016] In a second aspect, an embodiment of the present application provides a communication method, which may be executed by a first network device or a module (such as a chip) in the first network device. The method includes: the network device sends indication information to the terminal device, and the indication information is used to instruct the terminal device to measure the reference signal of the first cell from the second network device, where the first cell is the cell accessed by the terminal device through the first network device; the network device also receives the signal quality of the reference signal from the terminal device. Therefore, the first network device can evaluate whether to hand over the terminal device to the second network device according to the signal quality. If the signal quality of the reference signal of the first cell from the second network device is poor, the terminal device can avoid continuing to switch to accessing the first cell through the second network device. For example, the terminal device can switch to other cells with good signal quality, reducing the probability of radio link failure caused by the terminal device performing the handover.

[0017] In a possible implementation method, the first network device sends a first moment and a second moment to the terminal device, where the first moment indicates the moment when the first network device stops providing services for the first cell, and the second moment indicates the moment when the second network device starts providing services for the first cell, where the second moment is less than or equal to the first moment.

[0018] In a possible implementation method, the first network device sending the indication information to the terminal device includes: the first network device sends measurement configuration information to the terminal device, the measurement configuration information includes the indication information, the measurement configuration information is used to configure the terminal device to measure the reference signal, the measurement configuration information includes a measurement object and reporting configuration information, where the measurement object is the measurement object corresponding to the first cell.

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

[0020] In a possible implementation method, the first network device sends first condition information to the terminal device, the first condition information includes the radio resource configuration information of the first candidate cell and the execution condition for switching to the first candidate cell; the first network device sends second condition information to the terminal device, and the second condition information is used to instruct to perform conditional handover to the first candidate cell when the signal quality of the reference signal of the first cell of the second network device measured is lower than a first threshold.

[0021] For the beneficial effects of various implementation methods of the first network device, reference can be made to the beneficial effects of the implementation methods of the terminal device in the first aspect, which will not be elaborated here.

[0022] In a third aspect, an embodiment of the present application provides 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 receives a first time and a second time from a first network device, where the first time indicates the time when the first network device stops providing services for a first cell, and the second time indicates the time when a second network device starts providing services for the first cell, and the second time is less than or equal to the first time; The terminal device receives second indication information; The terminal device determines, 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 solution, it can be ensured that the terminal devices in the first cell between the second time and the first time all access the first cell through the first network device, thereby avoiding interference between terminal devices in the same cell caused by some terminal devices accessing the first cell through the first network device and some terminal devices accessing the first cell through the second network device.

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

[0024] In a possible implementation method, the second indication information is used to indicate that the terminal device does not access the first cell through the second network device between the second time and the first time.

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

[0026] In a fourth aspect, an embodiment of the present application provides 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 sends a first time and a second time to the terminal device, where the first time indicates the time when the first network device stops providing services for a first cell, and the second time indicates the time when a second network device starts providing services for the first cell, and the second time is less than or the first time; The first network device sends second indication information to the terminal device, and the second indication information is used to determine that the terminal device does not access the first cell through the second network device between the second time and the first time.

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

[0028] For the beneficial effects of various implementation methods of the first network device, reference can be made to the beneficial effects of various implementation methods of the terminal device in the third aspect, which will not be elaborated herein.

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

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

[0031] In a seventh aspect, embodiments of the present application provide a communication device, including units or means for performing each step of any of the implementation methods in the first to fourth aspects above.

[0032] In an eighth aspect, embodiments of the present application provide a communication device, including a processor and an interface circuit. The processor is used to communicate with other devices through the interface circuit and execute any of the implementation methods in the first to fourth aspects above. The processor includes one or more.

[0033] In a ninth aspect, embodiments of the present application provide a communication device, including a processor coupled to a memory. The processor is used to call a program stored in the memory to execute any of the implementation methods in the first to fourth aspects above. The memory may be located inside or outside the device. And the processor may be one or more.

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

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

[0036] In the eleventh aspect, an embodiment of the present application further provides a computer program product, which includes a computer program or instructions. When the computer program or instructions are run by a communication device, any implementation method in the above first aspect to the fourth aspect is executed.

[0037] In the twelfth aspect, an embodiment of the present application further provides a computer-readable storage medium, in which instructions are stored. When they are run on a communication device, any implementation method in the above first aspect to the fourth aspect is executed.

[0038] In the thirteenth aspect, an embodiment of the present application further provides a chip system, including: a processor for executing any implementation method in the above first aspect to the fourth aspect.

[0039] In the fourteenth aspect, an embodiment of the present application further provides a communication system, including a terminal device for executing any implementation method in the first aspect and a first network device for executing any implementation method in the fourth aspect. Description of the Drawings

[0040] Fig. 1(a) is a schematic diagram of the architecture of the communication system applied in the embodiment of the present application;

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

[0042] Fig. 2(a) is a schematic diagram of the architecture of the NTN-based communication system applied in the embodiment of the present application;

[0043] Fig. 2(b) is another schematic diagram of the architecture of the NTN-based communication system applied in the embodiment of the present application;

[0044] Fig. 2(c) is another schematic diagram of the architecture of the NTN-based communication system applied in the embodiment of the present application;

[0045] Figure 3 is a schematic diagram of the flowchart of the communication method provided in the embodiment of the present application;

[0046] Fig. 4(a) is another schematic diagram of the flowchart of the communication method provided in the embodiment of the present application;

[0047] Fig. 4(b) is another schematic diagram of the flowchart of the communication method provided in the embodiment of the present application;

[0048] Fig. 4(c) is a schematic diagram of the orbital information represented in the Kepler orbit format provided in the embodiment of the present application;

[0049] Fig. 4(d) is a schematic diagram of the orbital information represented in the state vector provided in the embodiment of the present application.

[0050] Figure 5Schematic structural diagram of the communication device provided by the embodiment of the present application;

[0051] Figure 6 Another schematic structural diagram of the communication device provided by the embodiment of the present application. Detailed implementation manners

[0052] Fig. 1(a) is a schematic architecture diagram of the communication system applied in the embodiment of the present application. The communication system 1000 shown in Fig. 1(a) includes a radio access network 100 and a core network 200. Optionally, the communication system 1000 further includes the Internet 300. Among them, the radio access network 100 may include at least one network device (such as 110a - 110c in Fig. 1(a)), and may further include at least one terminal device (such as 120a - 120i in Fig. 1(a)). The terminal device is connected to the network device wirelessly, and the network device is connected to the core network wirelessly or wiredly. The core network device and the network device may be independent 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 the functions of part of the core network device and part of the network device may be integrated on a physical device. The terminal devices can be connected to each other, and the network devices can be connected to each other, either wiredly or wirelessly. Fig. 1(a) is only a schematic diagram, and the communication system may further include other network devices, such as wireless relay devices and wireless backhaul devices, which are not drawn in Fig. 1(a).

[0053] A network device is an access device through which a terminal device accesses a communication system in a wired or wireless manner. The network device can be a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next generation NodeB (gNB) in a 5th generation (5G) mobile communication system, a next generation NodeB in a 6th generation (6G) mobile communication system, a base station in a future mobile communication system, or an access node in a wireless fidelity (WiFi) system, etc.; it can also be a module or unit that completes some functions of the base station. For example, it can be a central unit (CU) or a distributed unit (DU). Here, the CU completes the functions of the radio resource control protocol and the packet data convergence protocol (PDCP) of the base station, and can also complete the function of the service data adaptation protocol (SDAP); the DU completes the functions of the radio link control layer and the medium access control (MAC) layer of the base station, and can also complete some or all of the functions of the physical layer. For specific descriptions of the above protocol layers, reference can be made to the relevant technical specifications of the 3rd generation partnership project (3GPP). The network device can be a macro base station (such as 110a in Figure 1(a)), a micro base station or an indoor station (such as 110b in Figure 1(a)), an aerial platform, an aircraft or a satellite (such as 110c in Figure 1(a)), or a relay node or a donor node, etc. Embodiments of the present application do not limit the specific technologies and specific device forms adopted by the network device.

[0054] A terminal device is a device with wireless transceiver capabilities that can send signals to a network device or receive signals from a network device. Terminal devices include, but are not limited to, terminal units, terminals, user equipment (UE), mobile stations, mobile terminals, etc. Terminal devices can be widely applied in various scenarios, such as device-to-device (D2D), vehicle to everything (V2X) communication, machine-type communication (MTC), internet of things (IOT), virtual reality, augmented reality, industrial control, autonomous driving, remote healthcare, smart grid, smart furniture, smart office, smart wearables, smart transportation, smart city, etc. Specifically, terminal devices can be mobile phones, tablet computers, computers with wireless transceiver capabilities, wearable devices, vehicles, airplanes, ships, robots, robotic arms, smart home devices, etc. Embodiments of this application do not limit the specific technologies and specific device forms adopted by terminal devices.

[0055] In embodiments of the present invention, a terminal device can have multiple states. For example, a terminal device can be in a connected state. A terminal device in the connected state can perform data transmission. For a terminal device in the connected state, connections can be established between it and the network device, as well as between the network device and the core network. A terminal device can also be in a deactivated state. Once a terminal device in the deactivated state has data to transmit, it can quickly establish a connection with the network device. For example, once a terminal device in the deactivated state has data to transmit, the network device can send a paging message, and after receiving the paging message, the terminal device can quickly establish a connection with the network device. Between a terminal device in the deactivated state and the network device, a connection may not be established, while a connection can be established between the network device and the core network for this terminal device. A terminal device can also be in an idle state. For a terminal device in the idle state, connections may not be established between it and the network device, nor between the network device and the core network.

[0056] The network device and the terminal device can be in fixed positions or movable. The network device and the terminal device can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; they can also be deployed on airplanes, balloons, and artificial satellites. Embodiments of this application do not limit the application scenarios of the network device and the terminal device.

[0057] The roles of network devices and terminal devices can be relative. For example, the aircraft or satellite 110c in Fig. 1(a) can be configured as a mobile network device. For the terminal devices 120i accessing the radio access network 100 through 110c, 110c is a network device; but for the network device 110a, 110c can also be a terminal device, that is, the communication between 110a and 110c is through the radio air interface protocol. Of course, the communication between 110a and 110c can also be through the interface protocol between network devices. At this time, relative to 110a, 110c can also be a network device. Therefore, network devices and terminal devices can both be uniformly referred to as communication devices. The 110a - 110c in Fig. 1(a) can be called communication devices with network device functions, and the 120a - 120i in Fig. 1(a) can be called communication devices with terminal device functions.

[0058] The communication between network devices and terminal devices, between network devices and network devices, and between terminal devices and terminal devices can be carried out through authorized spectrum, can also be carried out through unlicensed spectrum, or can be carried out through both authorized spectrum and unlicensed spectrum at the same time; it can communicate through the spectrum below 6 gigahertz (GHz), can also communicate through the spectrum above 6 GHz, or can also use the spectrum below 6 GHz and the spectrum above 6 GHz at the same time. 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 network devices can also be executed by modules (such as chips) in the network devices, or can be executed by a control subsystem including network device functions. The control subsystem including network device functions here can be the control center in application scenarios such as smart grid, industrial control, intelligent transportation, and smart city. The functions of terminal devices can also be executed by modules (such as chips or modems) in the terminal devices, or can be executed by a device including terminal device functions.

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

[0061] In this application, the numbering of terms is generally for the convenience of distinction. The numbering does not imply an order or priority difference among the terms. For example, for the "first network device" and the "second network device", the "first" and "second" are usually only used to distinguish these two network devices and should not limit 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 functions of the core network. 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 is configured to implement the functions of the PDCP layer and above protocol layers (such as the radio resource control (RRC) layer and / or the SDAP layer, etc.); the DU is configured to implement the functions of the protocol layers below the PDCP layer (such as the radio link control (RLC) layer, the MAC layer, and / or the physical (PHY) layer, etc.). Another example is that the CU is configured to implement the functions of the protocol layers above the PDCP layer (such as the RRC layer and / or the SDAP layer), and the DU is configured to implement the functions of the PDCP layer and below protocol layers (such as the RLC layer, the MAC layer, and / or the PHY layer, etc.).

[0064] The above configurations of the CU and DU are just examples, and the functions of the CU and DU can also be configured as needed. For example, the CU or DU can be configured to have the functions of more protocol layers, or the CU or DU can be configured to have partial processing functions of the protocol layers. For example, part of the functions of the RLC layer and the protocol layers above the RLC layer are set in the CU, and the remaining functions of the RLC layer and the protocol layers below the RLC layer are set in the DU. Another example is that the functions of the CU or DU can be divided according to the service type or other system requirements. For example, divided by latency, the functions that require a smaller latency for processing time are set in the DU, and the functions that do not require meeting this latency requirement are set in the CU.

[0065] The DU and the RU can cooperate to jointly implement the functions of the PHY layer. One DU can be connected to one or more RUs. The functions of the DU and the RU can be configured in multiple ways according to the design. For example, the DU is configured to implement baseband functions, and the RU is configured to implement mid-RF functions. Another example is that the DU is configured to implement the high-layer functions in the PHY layer, and the RU is configured to implement the low-layer functions in the PHY layer or implement the low-layer functions and RF functions. The high-layer functions in the physical layer can include a part of the functions of the physical layer, and this part of the functions is closer to the MAC layer. The low-layer functions in the physical layer can include another part of the functions of the physical layer, and this part of the functions is closer to the mid-RF side.

[0066] As described in the background art, NTN is introduced into the 5G system and the subsequent evolved system architecture. In the embodiments of the present application, the non-terrestrial network device in NTN is taken as a satellite for description. It should be understood that the non-terrestrial network device in NTN can be other non-terrestrial network devices.

[0067] Generally speaking, according to the orbital altitude of the satellite, the satellite can be divided into high-orbit satellites and medium-low-orbit satellites. Among them, high-orbit satellites are also called geosynchronous orbit (GSO) satellites. The movement speed of GSO satellites is the same as the earth's rotation system. Therefore, GSO satellites remain stationary relative to the ground. The corresponding coverage of GSO satellite cells is relatively large, and the general cell diameter is 500 kilometers. Among them, medium-low-orbit satellites move relatively fast relative to the ground. Therefore, the service coverage area provided by medium-low-orbit satellites also moves accordingly. Correspondingly, the cells provided by medium-low-orbit satellites for coverage can be divided into ground quasi-stationary cells and ground mobile cells. Among them, the ground quasi-stationary cell refers to the cell formed by the moving satellite by adjusting its beamforming, and the position of the cell on the ground is stationary within a certain period of time. The ground mobile cell refers to the cell with a small beam coverage of the satellite that moves with the movement of the satellite without dynamically adjusting its beam direction.

[0068] According to the working mode, satellites can generally be divided into two forms. The first form is the transparent form, also known as the forwarding form. In this form, the satellite forwards the cell information of ground network devices (such as base stations) or other satellites, mainly for forwarding signals. Its functions can be radio frequency filtering, frequency conversion, and / or signal amplification. In this form, the satellite can also be regarded as a relay to regenerate and forward the signal, which can be to regenerate and forward the physical layer signal. The second form is the regenerative form. In this form, the satellite has all the processing functions of the base station or part of the processing functions of the base station.

[0069] Schematic diagram of a communication system architecture based on NTN provided by an embodiment of the present application as shown in FIG. 2(a). Under the system architecture shown in FIG. 2(a), at least one satellite can operate in a transparent mode. For example, the communication system can at least include a first satellite 201, a second satellite 202, a first terminal device 211, and a first base station 221. Among them, both the first satellite 201 and the second satellite 202 operate in a transparent mode, and both the first satellite 201 and the second satellite 202 can be connected to the first base station 221. The first terminal device 211 can communicate with the first base station 211 through the first satellite 201 during a certain period. The first satellite 201 can have a first cell covering the first terminal device 211. In 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 this first cell can be called the first cell of the first satellite 201. In the method of this embodiment, as the first satellite 201 moves, the first cell cannot be covered. The second satellite 202 can provide the same first cell to serve 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 through the first satellite 201 to communicating with the first base station 221 through the second satellite 202. Similarly, the second satellite 202 can also be used 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 cells covering the first terminal device 211 by the first satellite 201 and the second satellite 202 are the same cell, that is, the first cell has not changed. For the first terminal device 211, although the satellite providing the communication service has changed, the covered cell has not changed. The so-called cell has not changed, or the same first cell provided by the first satellite 201 and the second satellite 202 can mean 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. In addition, the frequency points of the synchronization signal and the physical broadcast signal block (SSB) transmitted in this same cell can also remain unchanged.

[0070] When the second satellite 202 provides the first cell to cover 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 the embodiments of the present application refers to the neighboring cell of the serving cell of the terminal device, for example, it can be 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, that is, the second cell, for the second terminal device 212. The second cell can be considered as a neighboring cell of the first cell and can also be used as a candidate cell for the first terminal device 211 to switch to. 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, which is not limited here.

[0072] Another schematic diagram of a communication system architecture based on NTN provided by an embodiment of the present application as shown in FIG. 2(b). In this communication system, at least at least one satellite can operate in a regenerative form. Exemplarily, the communication system described in FIG. 2(b) includes a first satellite 203, a second satellite 204, and a first terminal device 213. Both the first satellite 203 and the second satellite 204 operate in a regenerative form. Similar to the communication system described in FIG. 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 refer to the description of the relationship between the first satellite 201, the second satellite 202, and the first cell covering the first terminal device 211 in FIG. 2(a) above. The first terminal device 213 communicates directly with the first satellite 203 or the second satellite 204. Similarly, the first terminal device 213 can communicate with the first satellite 203 during a certain period of time. The first terminal device 213 accesses the first cell through the first satellite 203. This first cell can be referred to as the serving cell of the first terminal device, and this first cell can also be referred to as the first cell of the first satellite 203. As the first satellite 203 moves, the first satellite 203 will no longer be able to cover the first cell. At this time, the second satellite 204 can cover the first cell. 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. This first cell is still the serving cell of the first terminal device 213, and this first cell can also be referred to as the first cell of the second satellite 204. For the first cell, the PCI corresponding to the first cell may not change before and after the switch. Similarly, the communication system described in FIG. 2(b) may also include a second terminal device 214, a second base station 223, a second cell, etc. This second cell can be considered as a neighboring cell of the first cell and can also be used as a candidate cell for the first terminal device 213 to switch. Details are not described here.

[0073] Another schematic diagram of a communication system architecture based on NTN provided by an embodiment of the present application as shown in Fig. 2(c). In this architecture, the first satellite 205 and the second satellite 206 have the processing functions of some base stations, such as the DU function, and the first base station 224 deploys the CU function of the 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 Fig. 2(c) may also include a second terminal device 216, a second base station 225, a first cell, a second cell, etc. The relationships between them can be referred to the descriptions of the schematic diagrams of the communication system architecture in Fig. 2(a) and Fig. 2(b) above, and will not be elaborated here. In the regenerative operating mode, it can be divided into regenerative satellites without inter-satellite links, that is, there is no inter-satellite link (ISL) between satellites; regenerative satellites with inter-satellite links, that is, there is an interface between satellites to directly interact data, where the inter-satellite link is the Xn interface.

[0074] The handover of the terminal device can be divided into two handover methods: hard handover and soft handover. In the hard handover method, the time periods during which the first satellite and the second satellite serve the first cell in the time dimension do not overlap. During handover, the first satellite first stops serving the terminal device through the first cell, and then the second satellite serves the terminal device through the first cell. For the terminal device, the terminal device first disconnects from the first satellite (for example, at the moment when the first satellite stops serving the terminal, the terminal device disconnects from the first satellite), and then connects to the second satellite. During the handover, the terminal device may experience a link interruption phenomenon. In the soft handover method, in the time dimension, the time periods during which the first satellite and the second satellite serve the first cell overlap. Before the first satellite stops serving the terminal device through the first cell, the second satellite has already started serving the terminal device through the first cell. For the terminal device, before disconnecting from the first satellite, the terminal device starts to synchronize with the second satellite, and then simultaneously maintains the connection with the cell through the first satellite and the second satellite, and then disconnects from the first satellite. In these two handover scenarios, when the satellite changes, the base station does not need to send a layer 3 handover command to the terminal device in the first cell, and the terminal device inherits the radio resource configuration previously configured by the base station for the terminal device. These two handovers can also be referred to as satellite switches with re-sync that require re-synchronization.

[0075] Taking Fig. 2(a) as an example, since the positions of the first satellite 201 and the second satellite 202 are different, for the first terminal device 211, 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 radio link failure between the first terminal device 211 and the second satellite 202. The embodiments of the present application provide a communication method, which can reduce the probability of radio link failure caused by the terminal device performing handover, thereby ensuring communication reliability.

[0076] Figure 3 It is a schematic flowchart of a communication method provided by an embodiment of the present application. This embodiment can reduce the probability of radio link failure caused by the terminal device performing handover. This embodiment is executed by a terminal device or a module in the terminal device (such as a chip), a first network device or a module in the first network device (such as a chip), and a module in the second network device (such as a chip). The terminal device can correspond to the first terminal device in Fig. 2(a), Fig. 2(b) or Fig. 2(c). The first network device can correspond to the first satellite in Fig. 2(a), Fig. 2(b) or Fig. 2(c). The second network device can correspond to the second satellite in Fig. 2(a), Fig. 2(b) or Fig. 2(c). Hereinafter, the case where the terminal device, the first network device and the second network device execute this method will be used as an example for description.

[0077] Step 301, the terminal device receives indication information from the first network device.

[0078] The current state of the terminal device is a terminal device accessing the first cell through the first network device. The first cell is called 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 services for the first cell during the first period of time, and the second network device provides services for the first cell during the second period of time, and the first period of time and the second period of time overlap in time. The PCI of the first cell remains unchanged during the first period of time and the second period of time.

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

[0080] The indication information is used to indicate that the terminal device measures the reference signal of the first cell from the second network device.

[0081] Optionally, the first network device may also send indication information #A to the terminal device, indicating support for soft handover from accessing the first cell by the first network device to accessing the first cell by the second network device. For example, the first network device sends, through a broadcast message, indication information on satellite handover that the first cell supports resynchronization to the terminal device, and sends, through the broadcast message, a first moment and a second moment (for example, before measuring the reference signal of the first cell from the second network device), where the first moment indicates the moment when the first network device stops providing services for the first cell, and the second moment indicates the moment when the second network device starts providing services for the first cell, where the second moment is less than or equal to the first moment, or the second moment is earlier than or equal to the first moment. The terminal device may measure the signal quality of the reference signal between the second moment and the first moment. In this way, the terminal device can determine when to measure the reference signal of the first cell of the second network device based on the received first moment and second moment.

[0082] In a possible implementation where the terminal device receives the indication information from the first network device, the terminal device receives measurement configuration information from the first network device, the measurement configuration information includes the indication information, the measurement configuration information is used to configure the terminal device to measure the reference signal of the first cell from the second network device, and the measurement configuration information further includes a measurement object, where the measurement object configures the frequency points and other information to be monitored by the terminal device. In this way, the terminal device can obtain the above indication information by receiving the measurement configuration information without the need to add an additional signaling to receive the indication information, thereby saving signaling.

[0083] Optionally, the measurement object may be a measurement object corresponding to the first cell (for a terminal device, it may also be referred to as a serving cell measurement object. The terminal device obtains the signal quality of the first cell based on this measurement object). The terminal device may measure the reference signal of the first cell from the second network device based on the measurement object corresponding to the first cell, and may add this indication information to the measurement object corresponding to the first cell to indicate that the terminal device measures the reference signal of the first cell from the second network device. Optionally, the measurement object may also be other measurement objects, and the network device may add this indication information to other measurement objects to indicate that the terminal device measures the reference signal of the first cell from the second network device. This other measurement object may be only used to measure the reference signal of the first cell received through the second network device, or may also be used to measure the reference signal of the 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 reference signal sent through the first cell by the second network device, and the reference signal of the first cell from the first network device is the reference signal sent through the first cell by the first network device, only with different expression forms.

[0084] Optionally, the measurement configuration information may include reporting configuration information, and the reporting configuration represents the criteria for triggering the reporting of measurement reports. Among them, triggering reporting can be divided into event-triggered reporting and periodic-triggered reporting. The configuration of event-triggered reporting includes various event categories, threshold values, the duration of meeting the triggering conditions, and the type of reference signal (such as SSB or channel state information reference signal (CSI-RS), etc.) (for example, event A4 is defined as the signal quality of a neighboring cell being better than a threshold value). Usually, after entering the measurement reporting condition, the terminal device will not immediately trigger reporting, and it needs to continuously meet the measurement reporting condition within the duration of meeting the triggering condition to trigger measurement reporting. Among them, the periodic-triggered reporting configuration includes the reporting period, the type of reference signal, and the white list cell list. The reporting configuration information contains this indication information (for example, this indication information is included in the reporting configuration information of event A4. Thus, it indicates that the terminal device takes the first cell from the second network device as a neighboring cell in this event A4. That is, it judges whether the signal quality of the first cell from the second network device meets the threshold value of this event A4). For this reporting configuration, the terminal device will evaluate whether the event is met or report only at the second moment and the first moment.

[0085] In another possible implementation for the terminal device to receive the 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. This event-triggered reporting is specifically used to measure or evaluate the signal quality of the first cell from the second network device as specified.

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

[0087] In another possible implementation for the terminal device to receive the 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), and the indication information can be sent to the terminal device through the RRC message or the MAC CE.

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

[0089] If the second network device is a satellite for transparent forwarding, then the reference signal is sent from the terrestrial 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 satellite in a regenerative form, then the reference signal is directly sent by the second network device to the terminal device.

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

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

[0092] As described above, the measurement configuration information may include measurement objects, which include synchronization signal and physical broadcast signal block (SSB) frequency, SSB subcarrier spacing, SSB-based measurement timing configuration (SMTC), whitelist cells, blacklist cells, etc. It should be noted that in this application, SSB and SMTC may also be replaced by other names, and this application does not limit them. For example, SSB may be referred to as a reference signal, and SMTC may be referred to as a 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 in each cell, when the base station sends down the measurement configuration information, in addition to indicating the SSB frequency points to be measured, it will also indicate the time domain position and duration for starting the SSB measurement. That is, it indicates to the terminal device the time window for searching for SSBs, and this time window is configured through SMTC. By configuring SMTC, the time window for the terminal device to search for SSBs can be effectively indicated, reducing unnecessary measurement power consumption of 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 measurement on a cell, including the SMTC period, SMTC duration, and SMTC offset. For example, the SMTC configuration is given by SMTC1, and the corresponding configuration cell for SMTC1 is SSB-MTC, which includes two sub-cells, 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, it can be the starting subframe of the time window for the UE to search for SSBs within the period).

[0096] duration represents the SMTC duration (characterizing the duration for which the measurement action should continue after the measurement action starts).

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

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

[0099] SFN mod T = (FLOOR(SMTC offset / 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 period / 10). CEIL() is rounding up.

[0102] Optionally, the measurement objects further include a whitelist cell and a blacklist cell. The network device may configure a specific list of cells to be measured, namely the whitelist cell list and the blacklist cell list. For the cells included in the blacklist, the terminal device no longer performs event measurement and measurement reporting on that cell. While the whitelist cell is the cell on which the terminal device will perform event measurement and measurement reporting.

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

[0104] The terminal device may measure the reference signal according to the specific configuration of the above measurement object.

[0105] Optionally, the measurement configuration information may further include measurement quantity configuration information. The measurement quantity configuration information is used to configure the measurement quantity, and the measurement quantity may include:

[0106] Reference signal received power (RSRP), which reflects the reception strength of the reference signal;

[0107] Received signal strength indicator (RSSI), which reflects the total signal strength of the current channel;

[0108] Reference signal received quality (RSRQ), which reflects the signal-to-noise ratio and interference level of the current channel quality, 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 measuring terminal devices.

[0110] Based on the above measurement quantity configuration information, the terminal device can determine which measurement quantities of the specific measurement reference signal, providing a basis for subsequent handover strategies. Generally, the measurement quantities used in handover strategies mainly use 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 the trigger report (including event-triggered reporting or periodic-triggered reporting) of a certain report configuration is satisfied, the terminal device reports a measurement report. The content of the measurement report includes at least one of the measurement ID MeasId, the serving cell measurement result measResultServingMOList, or the neighbor cell measurement result measResultNeighCells. Among them, the serving cell measurement result includes the physical cell identifier and the cell-level measurement results, such as the cell-level RSRP, RSRQ, or SINR measurement results. 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 measurement results. The neighbor cell measurement quantities include the physical cell identifier and the cell-level measurement results of the neighbor cell, and can also include the beam-level measurement results of the neighbor cell.

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

[0112] The terminal device may 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), where the first time indicates the time when the first network device stops providing services for the first cell, and the second time indicates the time when the second network device starts providing services for the first cell, where 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 starts measuring the reference signal of the first cell from the second network device at a certain time between the second time and the first time.

[0113] The terminal device may also perform different measurements at different times based on the SMTC information. For example, before the second time or after the first time, the terminal device measures the reference signal of the neighboring cell of the first cell based on the second SMTC information. Between the second time and the first time, the terminal device measures the reference signal of the first cell of the second network device and the reference signal of the neighboring cell of the first cell based on the first SMTC information. For another example, before the second time, the terminal device measures the reference signal of the neighboring cell and the reference signal of the first cell from the first network device based on the second SMTC information, or before the second time, the terminal device only measures the reference signal of the neighboring cell based on the second SMTC information. For another example, between the second time and the first time, the terminal device measures the reference signal of the first cell from the second network device and the reference signal of the neighboring cell based on the first SMTC information, or between the second time and the first time, the terminal device measures the reference signal of the first cell from the second network device, the reference signal of the first cell from the first network device, and the reference signal of the neighboring cell 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 of the first cell from the first network device based on the first SMTC information, or may directly measure the reference signal of the first cell from 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, where the third SMTC information is used for 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 and the first SMTC may not appear simultaneously. For example, the terminal device receives a second SMTC and a third SMTC from the first network device. The first network device may configure multiple SMTCs (abbreviated as SMTC set #1) for the terminal device (for example, 4 SMTCs can be configured. The periods and durations of these 4 SMTCs are the same, only the SMTC offsets are different), and these SMTCs are used to measure the reference signals of the neighboring cells of the first cell or the reference signal of the first cell. For the third SMTC, in one implementation, the first network device sends multiple SMTC configurations to the terminal device in the measurement configuration. The multiple SMTC configurations include the second SMTC and the third SMTC. The first network device sends indication information #C in the measurement configuration information to indicate which SMTC in the multiple SMTC configurations is the third SMTC. For example, the indication information #C indicates which SMTC configuration in the 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 of the first cell from the second network device, and 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 at most 3 SMTCs in the SMTC set #1 for the terminal device to measure the reference signals of the neighboring cells of the first cell or the reference signal of the first cell. Optionally, the terminal device uses the third SMTC only between the second moment and the first moment. 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 moment and the first moment, when the terminal device measures the reference signal of the first cell from the second network device, due to the high-speed mobility of the first network device and the second network device, the time deviation of the reference signal of the first cell from the first network device and the reference signal of the first cell from the second network device arriving at the terminal device changes dynamically. This may cause the previously configured SMTC configuration for measuring the reference signal of the first cell from the second network device to be unreasonable. Therefore, the network device may configure the terminal device to measure the propagation delay difference between the terminal device and the first network device and the second network device (for example, the first network device configures the measurement of the propagation delay difference between the terminal device and the first network device and the second network device for the terminal device through RRC message #1). Further optionally, the network device (such as the first network device) notifies the terminal device to report the propagation delay difference between the terminal device and the first network device and the second network device after the second moment. For example, the first network device carries indication information #E in RRC message #1 to indicate that the terminal device reports the propagation delay difference between the terminal device and the first network device and the second network device after the second moment. After the terminal device reports the propagation delay difference between the terminal device and the first network device and the second network device (such as propagation delay difference #1) to the first network device, when the terminal device detects that the latest propagation delay difference between the terminal device and the first network device and the second network device (such as propagation delay difference #2) exceeds a certain threshold compared with the previously reported propagation delay difference by the terminal device (such as propagation delay difference #1) (for example, the first network device configures this threshold in RRC message #1), the terminal device reports the latest propagation delay difference between the terminal device and the first network device and the second network device (such as propagation delay difference #2) to the first network device.

[0116] Between the second moment and the first moment, after the terminal device obtains the reference signal quality of the first cell from the second network device and the reference signal quality of the first cell from the first network device, it will respectively maintain the measured reference signal quality of the first cell from the second network device and the reference signal quality of the first cell from the first network device between the second moment and the first moment. Exemplarily, the measurement output of the reference signal is divided into beam-level measurement results (which can also be called measurement results at the reference signal level, such as the measurement results corresponding to SSB) and cell-level measurement results. After the physical layer filtering is completed, the beam-level measurement results are obtained, and the beam-level measurement results are input into the radio resource control (RRC) layer for further processing. On the one hand, the RRC layer performs beam combining to obtain the cell-level measurement results, and then filters the cell-level measurement results to obtain the reference signal quality finally used for reporting. On the other hand, after the RRC layer completes the filtering, it can perform beam selection and report the selected beam to the network. The terminal device respectively maintains the measured reference signal quality of the first cell from the second network device and the reference signal quality of the first cell from the first network device between the second moment and the first moment. The terminal device respectively 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 at the physical layer to obtain the beam-level measurement results. Then, the beam-level reference signal quality of the first cell of the first network device and the beam-level reference signal quality of the first cell of the second network device are respectively input into the RRC layer for filtering and beam combining to obtain the cell-level reference signal quality of the first cell of the first network device and the cell-level reference signal quality of the first cell of the second network device. The cell-level reference signal quality of the first cell of the first network device and the cell-level reference signal quality of the first cell of the second network device can be used for reporting to the network. Optionally, the terminal device can also perform beam selection after the RRC completes the filtering and report the selected reference signal beam of the first cell of the second network device or the reference signal beam of the first cell of the first network device to the network.

[0117] Optionally, when the terminal device determines that the reference signal quality of the first cell from the second network device is relatively poor (for example, when the reference signal quality of the first cell from the second network device is lower than the first threshold), the terminal device does not perform soft handover. That is, for the terminal device, the terminal device needs to wait for the handover configuration or handover command sent by the first network device or wait until the execution condition of the conditional handover sent by the first network device is met before switching to the 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 the first threshold), the terminal device performs a soft handover.

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

[0120] The terminal device can trigger the reporting of the measured reference signal quality to the first network device according to a standard for triggering the reporting of a measurement report. For example, the measurement configuration information can include reporting configuration information, and the reporting configuration represents the standard for triggering the reporting of a measurement report. Among them, the triggering of reporting can be divided into event-triggered reporting and periodic-triggered reporting. The configuration of event-triggered reporting includes various event categories, threshold values, the duration of meeting the triggering conditions, and the type of reference signal (such as SSB or channel state information reference signal (CSI-RS), etc.). Usually, after entering the measurement reporting condition, the terminal device will not immediately trigger the reporting, and it needs to continuously meet the measurement reporting condition within the duration of meeting the triggering condition to trigger the measurement reporting. Among them, the periodic-triggered reporting configuration includes the reporting period, the type of reference signal, and the whitelist cell list. The terminal device will perform corresponding measurements according to the configuration content and send measurement reports according to the reporting period and interval. For each reporting configuration information, the network device will assign a corresponding reporting configuration identifier (abbreviated as ReportConfigId).

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

[0122]

[0123] The measurement ID measId associates the measurement object identifier MeasObjectId with the measurement report configuration identifier reportConfigId, thereby associating the measurement object with the measurement report configuration. When the terminal device sends a measurement report to the network device, it indicates measId to the network device. The network device can find the corresponding measObjectId and reportConfigId based on measId, and then determine what event the received measurement report is for. The network device can also link multiple measurement objects to the same measurement report configuration by configuring multiple measIds, or link multiple measurement report configurations to the same measurement object. For example, the measurement report sent by the terminal device to the first network device carries the reference signal quality of the first cell from the second network device that is measured.

[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 of the first cell received from the second network device according to the measurement configuration corresponding to the measurement object associated with the report configuration, and reports the measurement result 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 policy. For example, the first network device can determine whether to hand over the terminal device to a neighboring cell (such as the second cell) based on the reference signal quality of the first cell received from the second network device. If the reference signal quality of the first cell from the second network device is poor, for example, below a certain threshold, the first network device configures a handover configuration or a handover command for the terminal device to hand over to a neighboring cell (such as the second cell). If the reference signal quality of the first cell from the second network device is good, for example, not lower than a certain threshold, the first network device does not need to configure a handover configuration or a handover command for the terminal device to hand over to a neighboring cell (such as the second cell), and the terminal device switches to access the first cell through the second network device (that is, performs 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 of the first cell received from the second network device to the third network device, and the third network device determines whether to hand over the terminal device to a neighboring cell (such as the second cell). If the reference signal quality of the first cell from the second network device is poor, for example, below a certain threshold, the third network device configures a handover configuration or a handover command for the terminal device to hand over to a neighboring cell (such as the second cell). If the reference signal quality of the first cell from the second network device is good, for example, not lower than a certain threshold, the third network device does not need to configure a handover configuration or a handover command for the terminal device to hand over to a neighboring cell (such as the second cell), and the terminal device switches to access the first cell through the second network device (that is, performs a soft handover from the first network device to the second network device).

[0126] Optionally, when the terminal device reports the measurement result according to the reporting configuration information, it may carry the reference signal quality of the first cell from the second network device in the neighbor cell measurement result (such as measResultNeighCells), or a new indication information #F for the reference signal quality of the first cell of the second network device is added 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 the 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 condition for switching to the first candidate cell.

[0129] The measurement configuration information corresponding to the first condition information may refer to the description in steps 301 to 304.

[0130] Optionally, when the first condition switch is a time-based condition switch, the time range [T1, T2] in the time-based condition switch may include the time range between the second moment and the first moment. For example, T1 is the same as the second moment, and T2 is the same as the first moment. The terminal device may measure the reference signal of the first cell received from the second network device within the time period [T1, T2], and outside the time period [T1, T2], there is no need to measure the reference signal of the first cell received from the second network device.

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

[0132] The terminal device evaluates whether the execution condition for switching to the first candidate cell is satisfied. When the execution condition is satisfied, the terminal device performs the condition switch, that is, switches to the first candidate cell (adopts the radio resource configuration information of the first candidate cell and accesses the first candidate cell).

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

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

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

[0136] Exemplarily, the terminal device determines, according to the indication of the second conditional information, whether the reference signal quality of the first cell from the second network device measured is lower than the first threshold. When the reference signal quality of the first cell from the second network device is lower than the first threshold, the terminal device performs a conditional handover to the first candidate cell according to the received first conditional information. If the execution condition of the first conditional information is satisfied, the terminal device hands over to the first candidate cell.

[0137] It should be noted that this application does not limit the sequence relationship between whether the terminal device measures whether the reference signal quality of the first cell from the second network device is lower than the first threshold and whether the terminal device evaluates whether the execution condition for handing over to the first candidate cell is satisfied. In one implementation, when the reference signal quality of the first cell from the second network device is lower than the first threshold, the terminal device starts to evaluate whether the execution condition for handing over to the first candidate cell is satisfied. When the execution condition for handing over to the first candidate cell is satisfied, the terminal device performs this conditional handover, that is, hands over to the first candidate cell (adopts the radio resource configuration information of the first candidate cell and accesses the first candidate cell). In another implementation, when the execution condition of the first conditional information is satisfied, the terminal device starts to evaluate whether the reference signal quality of the first cell from the second network device is lower than the first threshold. When the reference signal quality of the first cell from the second network device is lower than the first threshold, the terminal device performs this conditional handover, that is, hands over to the first candidate cell (adopts the radio resource configuration information of the first candidate cell and accesses the first candidate cell). In another implementation, when the terminal device receives the first conditional information, it starts to evaluate whether the execution condition for handing over to the first candidate cell is satisfied. When the terminal device receives the second conditional information, it evaluates whether the reference signal quality of the first cell from the second network device is lower than the first threshold. When both are satisfied, the terminal device performs this conditional handover, that is, hands over to the first candidate cell (adopts the radio resource configuration information of the first candidate cell and accesses the first candidate cell).

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

[0139] In the embodiments of this application, based on Figure 3In the method of the embodiment, the terminal device measures the reference signal quality of the first cell from the second network device according to the indication information, and sends the reference signal quality to the network device. Based on this reference signal quality, the probability of radio link failure caused by the terminal device performing handover can be reduced. Further, according to the above solution, after the network device receives this reference signal, it can determine the handover strategy of the terminal device according to the quality of this reference signal. For example, if the network device determines that the quality of this reference signal is poor, it can instruct the terminal device not to continue to handover to access the first cell through the second network device, or it can also instruct the terminal device to handover to other cells with good signals, such as the neighboring cell (the second cell) of the first cell.

[0140] FIG. 4(a) is a schematic flowchart of another communication method provided by an embodiment of the present 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. Hereinafter, an example in which the terminal device, the first network device, and the second network device execute this method will be used for illustration.

[0141] This method includes the following steps:

[0142] Step 401a, the terminal device receives a first moment and a second moment from the first network device.

[0143] The first moment indicates the moment when the first network device stops providing services for the first cell, and the second moment indicates the moment when the second network device starts providing services for the first cell, where the second moment is less than or equal to the first moment. Among them, the relationship between the first cell, the first network device, and the second network device can refer to the description of the embodiment in FIG. 4, which will not be elaborated here.

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

[0145] For the terminal device resident in the first cell through the first network device, it can start measuring the reference signal sent by the second network device at a certain moment between the second moment and the first moment. When the reference signal sent by the second network device is better than the second threshold, the terminal device can change to resident in the first cell through the second network device. Optionally, the first network device can send the value of the second threshold to the terminal device through a broadcast message.

[0146] Step 402a, the terminal device receives the second indication information.

[0147] Optionally, the second indication information is used to indicate that the terminal device does not access or camp on the first cell via the second network device between the second moment and the first moment.

[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 moment and the first moment, the terminal device does not access or camp on the first cell via the second network device.

[0149] The terminal device may receive the second indication information via the first network device. Optionally, when the terminal device camps on the first cell via the first network device, between the second moment and the first moment, the terminal device does not change to camping on the first cell via the second network device, but instead selects to access the first cell via the first network device. In this case, the terminal device may receive the first moment and the second moment via the first network device.

[0150] Optionally, the terminal device may also receive the second indication information via the second network device. The second network device may send the second indication information to the terminal device in a broadcast manner. The second network device may also broadcast information about 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 just powers on within the coverage area of the first cell and receives the signal of the second network device, in this case, according to the second indication information, between the second moment and the first moment, the terminal device does not access the first cell via the second network device, but instead selects to access the first cell via the first network device.

[0151] In a possible implementation, a third network device provides services for a second cell, which is a neighboring cell of a first cell. The third network device sends third indication information to a terminal device of the second cell, and the third indication information is used to indicate that the first cell will provide services through the first network device and the second network device at the same time between the second moment and the first moment, or indicate that the first cell will provide services for the first cell through the first network device and the second network device at the same time between the second moment and the first moment. The third indication information includes the second moment and the first moment. The terminal device residing in the second cell will not reside in the first cell through the second network device between the second moment and the first moment. Optionally, the third indication information is also used to indicate the ephemeris information and / or reference signal configuration (for example, the index of the reference signal) corresponding to the first cell in the first network device, or to indicate the ephemeris information and / or reference signal configuration (for example, the index of the reference signal) corresponding to the first cell in the second network device, so that the terminal device residing in the second cell can know which reference signals of the first cell are sent through the first network device and which reference signals of the first cell are sent through the second network device based on the reference signal configuration corresponding to the first cell in the first network device or the reference signal configuration corresponding to the second network device, so that the terminal device residing in the second cell can know whether the received reference signal of the first cell is sent through the first network device.

[0152] Step 403a: The terminal device determines not to access or reside in the first cell through the second network device between the second moment and the first moment based on the second indication information.

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

[0154] Optionally, for the terminal equipment in the idle state or inactive state of the second cell (the terminal equipment of the second cell may also be in the connected state), only the reference signal sent by the first cell through the first network device is measured before the second moment, and only the reference signal sent by the first cell through the second network device is measured after the first moment, and the reference signal sent by the first cell through the first network device and the reference signal sent by the first cell through the second network device are measured simultaneously between the second moment and the first moment, or only the reference signal sent by the first cell through the first network device is measured between the second moment and the first moment. In this way, it can be ensured that when there are two network devices in the first cell providing services at the same time, the terminal equipment of the second cell measures the reference information of the neighboring cell through the corresponding network device in different time periods, so that the neighboring cell measurement can be performed more accurately.

[0155] In the embodiments of the present application, based on the method of the embodiment shown in FIG. 4(a), it can be ensured that the terminal devices in the first cell between the second moment and the first moment all access or camp on the first cell through the first network device, thereby avoiding the situation where some terminal devices access or camp on the first cell through the first network device and some terminal devices access or camp on the first cell through the second network device, which may cause interference between the terminal devices in the same cell.

[0156] It can be understood that in order to implement the functions in the above embodiments, the terminal device or the first network device includes the corresponding hardware structure and / or software module for executing each function. Those skilled in the art should easily realize that, combining the units and method steps of each example described in the embodiments disclosed in the present application, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in the way of hardware or computer software driving hardware depends on the specific application scenario and design constraint conditions of the technical solution.

[0157] FIG. 4(b) is a schematic flowchart of another communication method provided by the embodiments of the present application. This embodiment is executed by the terminal device or a module (such as a chip) in the terminal device, the first network device or a module (such as a chip) in the first network device, and the second network device or a module (such as a chip) in the second network device. Hereinafter, an example in which the terminal device, the first network device, and the second network device execute this method will be used for illustration.

[0158] This 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 also receives the second moment from the first network device.

[0161] Among them, the relationship between the first moment, the second moment, the first cell, the first network device, and the second network device can be referred to Figure 3 the description of the embodiments, which will not be elaborated here. The terminal device can be in a connected state, a deactivated state, or an idle state, and the state of the terminal device is not limited here.

[0162] Optionally, the first moment and the second moment can be carried in the system information (such as System Information 19) from the first network device. The terminal device receives the system information from the first network device to obtain the first moment and the second moment. The system information may also carry the 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, the system information may also carry indication information #D indicating support for satellite handovers that require resynchronization (i.e., when the satellite changes but the PCI of the cell remains unchanged, the first network device supports not sending a layer 3 handover command to the terminal device in this first cell). Optionally, the indication information #D may also include the 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 position of the second network device corresponding to this epoch time. The terminal device can calculate the position of the second network device at the current moment based on the position of the second network device corresponding to this 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 this system information, or the system frame number indicated in the epoch time indicates the system frame closest to the system frame when the terminal device receives this system information.

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

[0165] Ephemeris information can also be referred to as orbital information, which refers to the operating path information of the non-terrestrial network device associated with this cell, and can also be referred to as the ephemeris information of the non-terrestrial network device associated with the cell. The determination method of ephemeris information can refer to Figure 4(c) or Figure 4(d). Figure 4(c) is a schematic diagram of orbital information represented in the Kepler orbit format provided by an embodiment of the present application, and Figure 4(d) is a schematic diagram of orbital information represented by state vectors provided by an embodiment of the present application.

[0166] The parameters shown in Figure 4(c) include orbital-level parameters. For example, i0 is the inclination angle, Ω0 is the longitude of the ascending node of the orbital plane, ω is the argument of perigee, etc. The above orbital-level parameters are used to determine the operating orbit. The parameters shown in Figure 4(d) include satellite-level parameters for determining the satellite position. For example, M0 is the mean anomaly at the epoch time.

[0167] When using orbital information represented by state vectors, the velocity vector in the state vector, such as (v x ,v y ,v z) etc., and rate and reference point information need to be provided for non-synchronous satellites. The position coordinate system based on in the state vector can be the geodetic coordinate system (λ, ψ, h) as shown in FIG. 4(d) or the Earth-centered Earth-fixed coordinate system (X, X, Z), etc., and the embodiments of the present 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 starts to perform downlink synchronization with the first cell through the second network device at the first moment. For soft handover, the terminal device performs downlink synchronization with the first cell through the second network device between the second moment and the first moment (for example, after any moment between the second moment and the first moment).

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

[0171] Step 403b, the terminal device receives the system information of the second network device.

[0172] The terminal device obtains the system information from the second network device (such as system information 19). Optionally, the terminal device obtains the system information of the second network device after performing downlink synchronization with the first cell through the second network device. For example, the terminal device can obtain the system information of the second network device without waiting for the timer #1 to time out after performing downlink synchronization with the first cell through the second network device, or the terminal device obtains the system information of the second network device after performing downlink synchronization with the first cell through the second network device and waiting for the timer #1 to time out. The system information sent by the second network device includes the corresponding auxiliary information in the second network device. When the terminal device obtains the system information sent by the second network device, the terminal device starts or restarts the timer #1 at the subframe moment indicated by the epoch time of the ephemeris information of the second network device received from the system information of the second network device, and the length of this timer is the effective length of the ephemeris information of the second network device received from the system information received from 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 performs data transmission (that is, the terminal device transmits and receives data according to the pre-configured authorization sent by the previous first network device or the terminal device listens to the downlink physical control channel sent by the second network device to obtain the authorization for transmitting and receiving data).

[0174] Optionally, if the system information of the second network device has not been obtained by the terminal device in step 403b, the terminal device may perform measurements on the neighboring cells of the first cell using the auxiliary information corresponding to the neighboring cells of the first cell in the second network device obtained in step 401b.

[0175] It should be noted that this application does not limit the sequence relationship of uplink and downlink synchronization, starting the timer, and obtaining the system information of the second network device.

[0176] In the embodiment of the present application, based on the method of the embodiment of FIG. 4(b), it can be ensured that after the terminal device synchronizes to the first cell through the second network device, the ephemeris information of the second network device sent by the second network device can be obtained in time, ensuring the handover performance of the terminal device. Further, the terminal device can obtain the ephemeris information of the neighboring cells of the first cell of the second network device in time, so that the neighboring cells of the first cell can be measured in time, ensuring the handover performance of the terminal device. In addition, by obtaining the ephemeris information of the second network device in time, the terminal device can maintain the ephemeris information of the second network device with the system frame number and sub-frame number of the first cell in the second network device, reducing the complexity of the terminal device.

[0177] Figure 5 and Figure 6 FIG. 12 is a schematic structural diagram of a possible communication device provided by an embodiment of the present 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 embodiment of the present application, the communication device may be a terminal device or a first network device, or may also 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 functions of the terminal device or the first network device in the method embodiments as described above Figure 3 , in FIG. 4(a) or FIG. 4(b).

[0179] When the communication device is used to implement the function of the terminal device in the above method embodiment, the transceiver unit 520 is configured to receive indication information from the first network device. The terminal device accesses the first cell through the first network device, and 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 further configured 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 configured to measure the reference signal of the first cell of the second network device.

[0180] In a possible implementation, the transceiver unit 520 is further configured to receive a first time and a second time from a first network device, where the first time indicates the time when the first network device stops providing services to a first cell, and the second time indicates the time when a second network device starts providing services to the first cell, where 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, where the third time is between the second time and the first time.

[0181] In a possible implementation, the transceiver unit 520 is further configured to receive measurement configuration information from the first network device, where the measurement configuration information includes the above-mentioned indication information, the measurement configuration information is used to configure the terminal device to measure a reference signal, and the measurement configuration information includes a measurement object and reporting configuration information, where the measurement object is the measurement object corresponding to the first cell.

[0182] In a possible implementation, the transceiver unit 520 is further configured to receive a first SMTC information and a second SMTC information from the first network device, where 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 a possible implementation, the transceiver unit 520 is further configured to receive first condition information from the first network device, where the first condition information includes radio resource configuration information of a first candidate cell and an execution condition for switching to the first candidate cell; the transceiver unit 520 is further configured to receive second condition information from the first network device, where the second condition information is used to indicate that when the signal quality of the reference signal of the first cell of the second network device measured is lower than a first threshold, perform a conditional handover to the first candidate cell.

[0184] In a 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; between the second time and the first time, 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.

[0185] In a 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 measure the signal quality of the first cell from the first network device between the second time and the first time.

[0186] In a possible implementation, the processing unit 510 is further configured to respectively 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 measured between the second moment and the first moment.

[0187] When the communication device 500 is used to implement the functions of the first network device in the above method embodiments, the transceiver unit 520 is configured to send indication information to the terminal device, where the indication information is used to instruct the terminal device to measure the reference signal of the first cell from the second network device, and the first cell is the cell to which the terminal device accesses through the first network device; the transceiver unit 520 is further configured to receive the signal quality of the reference signal from the terminal device.

[0188] In a possible implementation, the transceiver unit 520 is further configured to send the first moment and the second moment to the terminal device, where the first moment indicates the moment when the first network device stops providing services for the first cell, and the second moment indicates the moment when the second network device starts providing services for the first cell, where the second moment is less than or equal to the first moment; a third moment is between the second moment and the first moment, and the third moment is the moment 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 a possible implementation, the transceiver unit 520 is further configured to send measurement configuration information to the terminal device, where the measurement configuration information includes indication information, and the measurement configuration information is used to configure the terminal device to measure the reference signal. The measurement configuration information includes a measurement object and reporting configuration information, where the measurement object is the measurement object corresponding to the first cell.

[0190] In a possible implementation, the transceiver unit 520 is further configured to send the first SMTC information and the second SMTC information to the terminal device, where 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 a possible implementation, the transceiver unit 520 is further configured to send first condition information to the terminal device, where the first condition information includes the radio resource configuration information of the first candidate cell and the execution condition for switching to the first candidate cell; the transceiver unit 520 is further configured to send second condition information to the terminal device, where the second condition information is used to indicate that when the signal quality of the reference signal of the first cell of the second network device measured is lower than the first threshold, perform a conditional handover to the first candidate cell.

[0192] For a more detailed description of the above processing unit 510 and transceiver unit 520, reference can be directly made to the relevant descriptions in the above method embodiments and will not be elaborated 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 can be understood that the interface circuit 620 can be a transceiver or an input / output interface. Optionally, the communication device 600 may further include a memory 630 for storing instructions executed by the processor 610, or input data required for the processor 610 to execute instructions, or data generated after the processor 610 executes instructions.

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

[0195] It can be understood that the processor in the embodiments of the present application can 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. The general-purpose processor can be a microprocessor or any conventional processor.

[0196] The method steps in the embodiments of the present application can be implemented in a hardware manner or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, and the software modules can be stored in a 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, removable hard disks, compact disc read-only memories (CD-ROMs), or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC. Additionally, the ASIC can be located in a terminal device or a network device. Of course, the processor and the storage medium can also exist as discrete components in an access network device or a terminal.

[0197] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in the form of a computer program product in whole or in part. The computer program product includes one or more computer programs or instructions. A computer program (English: Computer Program) refers to a set of instructions that direct the actions of an electronic computer or other device with message processing capabilities at each step, usually written in a certain programming language and running on a certain target architecture. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are executed in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer program or instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer program or instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center in a wired or wireless manner. The computer-readable storage medium can be any available medium that can be accessed by a computer, or a data storage device such as a server or data center that integrates 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 disc; it can also be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium can be a volatile or non-volatile storage medium, or can include both volatile and non-volatile types of storage media.

[0198] In various embodiments of the present application, if there is no special description and logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other. The technical features in different embodiments can be combined to form new embodiments according to their internal logical relationships.

[0199] In the present application, "at least one" means one or more, and "a plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone, where A and B can be singular or plural. In the text description of the present application, the character " / " generally represents an "or" relationship between the associated objects before and after; in the formulas of the present application, the character " / " represents a "division" relationship between the associated objects before and after.

[0200] It should be understood that the various numerical numbers involved in the embodiments of the present application are only for the convenience of description and are not used to limit the scope of the embodiments of the present application. The magnitudes of the serial numbers of the above processes do not mean the sequence of execution, and the execution sequence of each process should be determined according to its function and internal logic.

Claims

1. A communication method, characterized in that, Executed by a terminal device or a chip for the terminal device, including: Receiving indication information from a first network device, where the terminal device is a terminal device accessing through a first cell of the first network device, and the indication information is used to instruct the terminal device to measure a reference signal sent by a second network device through the first cell; Receiving the reference signal sent by the second network device through the first cell; Measuring the signal quality of the reference signal based on the indication information; Sending the signal quality of the reference signal to the first network device.

2. The method according to claim 1, characterized in that, The measuring the signal quality of the reference signal based on the indication information includes: Receiving a first time and a second time from the first network device, where the first time indicates the time when the first network device stops providing services for the first cell, and the second time indicates the time when the second network device starts providing services for the first cell, and the second time is earlier than or equal to the first time; Measuring the signal quality of the reference signal between the second time and the first time.

3. The method according to claim 1 or 2, characterized in that, The receiving the indication information from the first network device includes: Receiving measurement configuration information from the first network device, where the measurement configuration information includes the indication information.

4. The method according to claim 3, wherein The measurement configuration information further includes a measurement object and reporting configuration information, where the measurement object is the measurement object corresponding to the first cell.

5. The method according to any one of claims 1 to 4, characterized in that, The measuring the signal quality of the reference signal based on the indication information includes: Receiving first Synchronization Signal and Physical Broadcast Signal Block SSB Measurement Timing Configuration SMTC information and second SMTC information from the first network device; Measuring 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; Measuring the reference signal of the neighboring cells of the first cell based on the second SMTC information.

6. The method according to claim 5, wherein The measuring 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 includes: Between the second time and the first time, measuring 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.

7. The method according to claim 5, wherein The measuring the reference signal of the neighboring cells of the first cell based on the second SMTC information includes: Before the second time or after the first time, measuring the reference signal of the neighboring cells of the first cell based on the second SMTC information.

8. The method according to any one of claims 2 to 6, characterized in that, The measuring the signal quality of the reference signal between the second time and the first time includes: Measuring the signal quality of the reference signal of the first cell of the second network device between the second time and the first time, and Measuring the signal quality of the reference signal of the first cell of the first network device between the second time and the first time.

9. The method according to claim 8, wherein The method further includes: Between the second moment and the first moment, the signal quality of the first cell reference signal of the second network device measured and the signal quality of the first cell reference signal of the first network device are respectively maintained.

10. The method according to any one of claims 1 to 9, characterized in that, The method further includes: Receiving first condition information from the first network device, where the first condition information includes radio resource configuration information of a first candidate cell and an execution condition for switching to the first candidate cell; Receiving second condition information from the first network device, where the second condition information is used to indicate that when the signal quality of the reference signal of the first cell of the second network device measured is lower than a first threshold, perform a conditional handover to the first candidate cell.

11. The method according to any one of claims 2 to 10, characterized in that, The method further includes: At a third moment, switching from accessing the first cell through the first network device to accessing the first cell through the second network device, where the third moment is between the second moment and the first moment.

12. A communication method, characterized in that, Executed by a first network device or a chip for the first network device, including: Sending indication information to a terminal device, where the indication information is used to instruct the terminal device to measure the reference signal of a first cell from a second network device, and the first cell is a cell accessed by the terminal device through the first network device; Receiving the signal quality of the reference signal from the terminal device.

13. The method according to claim 12, wherein The method further includes: Sending a first moment and a second moment to the terminal device, where the first moment indicates the moment when the first network device stops providing services for the first cell, and the second moment indicates the moment when the second network device starts providing services for the first cell, where the second moment is earlier than or equal to the first moment.

14. The method according to claim 12 or 13, characterized in that, The sending the indication information to the terminal device includes: Sending measurement configuration information to the terminal device, where the measurement configuration information includes the indication information.

15. The method according to claim 14, wherein The measurement configuration information further includes a measurement object and reporting configuration information, where the measurement object is the measurement object corresponding to the first cell.

16. The method according to any one of claims 12 to 15, characterized in that, The method further includes: Sending first SSB measurement timing configuration SMTC information and second SMTC information to the terminal device, where 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 configuration information is used to measure the reference signal of the neighboring cells of the first cell.

17. The method according to any one of claims 12 to 16, characterized in that, The method further includes: Sending first condition information to the terminal device, where the first condition information includes radio resource configuration information of a first candidate cell and an execution condition for switching to the first candidate cell; Sending second condition information to the terminal device, where the second condition information is used to indicate that when the signal quality of the reference signal of the first cell of the second network device measured is lower than a first threshold, perform a conditional handover to the first candidate cell.

18. A communication device, characterized in that, Including a module for executing the method according to any one of claims 1 to 11, or the method according to any one of claims 12 to 17.

19. A communication device, characterized in that, Comprising a processor; when the communication device is running, the processor executes computer instructions to perform the method according to any one of claims 1 to 11, or to perform the method according to any one of claims 12 to 17.

20. A communication device, characterized in that, Comprising a processor and an interface circuit, the processor is used to communicate with other devices through the interface circuit and perform the method according to any one of claims 1 to 11, or to perform the method according to any one of claims 12 to 17.

21. A computer program product, characterized in that, The computer program product comprises instructions which, when run on a processor, cause the processor to perform the method according to any one of claims 1 to 11, or to perform the method according to any one of claims 12 to 17.

22. A computer-readable storage medium, characterized in that, A computer program or instructions are stored in the storage medium, and when the computer program or instructions are executed by the communication device, the method according to any one of claims 1 to 11, or the method according to any one of claims 12 to 17 is implemented.

23. A communication system, characterized in that, Comprising a terminal device for performing the method according to any one of claims 1 to 11, and a network device for performing the method according to any one of claims 12 to 17.

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