Communication method and apparatus

Abstract

The application discloses a communication method and device, which are used for providing a CHO failure processing mechanism in a scenario where a CHO execution condition is based on location information and / or time information and / or signal quality information. When a terminal device has a radio link failure in a source cell before the CHO execution condition is met, or has an access or handover failure in a candidate cell after the CHO execution condition is met, or receives a first message from a source network device for indicating a traditional handover before the CHO execution condition is met, but the executed traditional handover fails, the terminal device can determine a cell for recovering a connection according to location, time, signal quality and CHO configuration information when the radio link failure occurs, so that the terminal device can perform reasonable processing after the radio link failure, the interruption delay caused by the radio link failure is reduced, and system performance is improved.

Description

TECHNICAL FIELD

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

[0002] A non terrestrial network (NTN) communication system deploys functions of an access network device or part of an access network device on a non terrestrial device such as a high-altitude platform or a satellite to provide seamless coverage for terminal devices, and the reliability of the NTN communication system is relatively high because the high-altitude platform or the satellite is located in the high sky and is less affected by natural disasters.

[0003] To improve the handover reliability, the network in the NTN communication system can configure a conditional handover (CHO) for a terminal device, and also has a corresponding failure handling mechanism when the CHO fails. However, in the prior art, a criterion for determining whether a CHO execution condition is met is usually adopted according to signal quality, and therefore the existing CHO failure handling mechanism is also implemented based on the CHO execution condition of the signal quality. When a CHO execution condition based on location information or time information is introduced, if the terminal device fails in the CHO, how to handle it at this time, there is currently no related solution. SUMMARY

[0004] The communication method and device in the embodiments of the present application are used to provide a CHO failure handling mechanism in a scenario of using a CHO execution condition based on location information and / or time information and / or signal quality information, so as to reduce the interruption delay caused by the CHO failure and improve the system performance.

[0005] In a first aspect, the embodiments of the present application provide a communication method, which can be executed by a terminal device or a component (such as a chip or a circuit) configured in the terminal device.

[0006] The method can include: receiving, by a terminal device, N conditional handover (CHO) configuration information from a source network device, each CHO configuration information indicating a CHO execution condition of a candidate cell corresponding to the CHO configuration information, the CHO execution condition being a CHO execution condition based on location information and / or time information and / or signal quality information, N being an integer greater than 1; before the CHO execution condition indicated by any CHO configuration information in the N CHO configuration information is met, a radio link failure occurs in a source cell; and determining, by the terminal device, a first cell to be accessed according to the N CHO configuration information, a current location and / or a current time and / or a current signal quality of the terminal device.

[0007] The technical solution provides a CHO failure processing mechanism when a terminal device has a radio link failure in a source cell before a CHO execution condition is met in a scenario where the CHO execution condition is based on location information and / or time information and / or signal quality information. The terminal device can determine a cell for recovering a connection according to a location, time, signal quality when the radio link failure occurs, and CHO configuration information, so that the terminal device can perform reasonable processing after the radio link failure occurs, reduce interruption delay caused by the radio link failure, and improve system performance.

[0008] In a possible design of the first aspect, if the current location and / or current time and / or current signal quality of the terminal device matches the first CHO configuration information in the N CHO configuration information, the terminal device can determine that the first cell is a first candidate cell corresponding to the first CHO configuration information, and then access the first cell according to the first CHO configuration information.

[0009] In a possible design of the first aspect, if the current location and / or current time and / or current signal quality of the terminal device does not match any of the N CHO configuration information, the terminal device can determine that the first cell is not a candidate cell, and the terminal device can perform re-establishment in the first cell.

[0010] In a possible design of the first aspect, after the terminal device has the radio link failure in the source cell, the method further includes: the terminal device generates a first report, and reports the first report to the first network device, where the first report includes one or more of the following information: cell information of an access failure cell, a connection failure type, cell information of the source cell, cell information of a cell for recovering a connection after the radio link failure, a C-RNTI allocated by the source cell to the terminal device, time information when the radio link failure occurs, time period information from the radio link failure to the connection recovery, time period information from the radio link failure to reporting the first report, time period information from the connection recovery to reporting the first report, location information of the terminal device when the radio link failure occurs, and signal quality of the source cell and / or each candidate cell.

[0011] In the second aspect, the embodiments of the present application provide a communication method, which can be executed by a terminal device, or by a component (for example, a chip or a circuit) configured in the terminal device.

[0012] The method can comprise: the terminal device receiving N conditional handover (CHO) configuration information from a source network device, each CHO configuration information indicating a CHO execution condition of a candidate cell corresponding to the CHO configuration information, the CHO execution condition being a CHO execution condition based on location information and / or time information and / or signal quality, N being an integer greater than 1; after the terminal device determines that the CHO execution condition indicated by the second CHO configuration information in the N CHO configuration information is met, the terminal device performing handover to a second candidate cell corresponding to the second CHO configuration information; and if the terminal device has access or handover failure in the second candidate cell, the terminal device determining a first cell to be accessed according to the N CHO configuration information, a current location of the terminal device, and / or a current time, and / or a current signal quality of the terminal device.

[0013] The above technical solution provides a CHO failure handling mechanism when the terminal device has access or handover failure in a candidate cell after the CHO execution condition is met in a scenario where the CHO execution condition is a CHO execution condition based on location information and / or time information and / or signal quality information. The terminal device can determine a cell to be accessed according to the location, time, signal quality, and CHO configuration information when the access or handover failure occurs, so that the terminal device can perform reasonable processing after the access or handover failure, reduce the interruption delay caused by the access or handover failure, and improve the system performance.

[0014] In a possible design of the second aspect, if the current location of the terminal device and / or the current time and / or the current signal quality of the terminal device match the first CHO configuration information in the N CHO configuration information, the terminal device can determine that the first cell is a first candidate cell corresponding to the first CHO configuration information, and then the terminal device can access the first cell, i.e., the first candidate cell, according to the first CHO configuration information.

[0015] In a possible design of the second aspect, if the current location of the terminal device and / or the current time and / or the current signal quality of the terminal device do not match the N CHO configuration information, and the current location of the terminal device is within the cell range of the source cell, the terminal device can determine that the first cell is the source cell, and then the terminal device can perform re-establishment in the source cell.

[0016] In a possible design of the second aspect, if the current location of the terminal device and / or the current time and / or the current signal quality of the terminal device do not match the N CHO configuration information, and the current location of the terminal device is not within the cell range of the source cell, the terminal device can determine that the first cell is neither a candidate cell nor the source cell, and then the terminal device can perform re-establishment in the determined first cell.

[0017] In a possible design of the second aspect, if the terminal device fails in access or handover in the second candidate cell, the method further includes: the terminal device generates a second report and reports the second report to the first network device, where the second report includes one or more of the following information: cell information of the cell in which the access fails, time period information from when the second CHO configuration information is received to when the handover trigger is received, time period information from when the handover trigger is received to when the access fails, time period information from when the access fails to when the connection recovers, time period information from when the connection recovers to when the second report is reported, time period information from when the access fails to when the second report is reported, time information when the access fails, location information of the terminal device when the access fails, and signal quality of the source cell and / or each candidate cell.

[0018] In a third aspect, an embodiment of the present application provides a communication method, which can be executed by a terminal device or a component (for example, a chip or a circuit) configured in the terminal device.

[0019] The method can include: receiving, by the terminal device, N conditional handover (CHO) configuration information from a source network device, where each CHO configuration information indicates a CHO execution condition of a candidate cell corresponding to the CHO configuration information, the CHO execution condition is a CHO execution condition based on location information and / or time information and / or signal quality, and N is an integer greater than 1; before the CHO execution condition indicated by any CHO configuration information in the N CHO configuration information is met, receiving, by the terminal device, a first message from the source network device, where the first message indicates to perform a traditional handover; and if the terminal device fails in performing the traditional handover, determining, by the terminal device, a first cell to be accessed according to the N CHO configuration information, a current location of the terminal device, and / or a current time, and / or a current signal quality.

[0020] The above technical solution provides a CHO failure processing mechanism when the terminal device receives a first message from the source network device indicating to perform a traditional handover before the CHO execution condition is met, but the traditional handover fails, in a scenario where the CHO execution condition is a CHO execution condition based on location information and / or time information and / or signal quality information. The terminal device can determine a cell to be accessed according to the location, time, signal quality when the traditional handover fails, and the CHO configuration information, so that the terminal device can perform reasonable processing after the traditional handover fails, reduce the interruption delay caused by the handover failure, and improve the system performance.

[0021] In a possible design of the third aspect, if the current location and / or the current time and / or the current signal quality of the terminal device matches one of the N CHO configuration information, the terminal device can determine that the first cell is a first candidate cell corresponding to the first CHO configuration information, and then access the first cell, i.e., the first candidate cell, according to the first CHO configuration information.

[0022] In a possible design of the third aspect, if the current location and / or the current time and / or the current signal quality of the terminal device does not match any of the N CHO configuration information, and the current location of the terminal device is within the cell range of the source cell, the terminal device can determine that the first cell is the source cell, and then perform re-establishment in the source cell.

[0023] In a possible design of the third aspect, if the current location and / or the current time and / or the current signal quality of the terminal device does not match any of the N CHO configuration information, and the current location of the terminal device is not within the cell range of the source cell, the terminal device can determine that the first cell is neither a candidate cell nor the source cell, and then perform re-establishment in the determined first cell.

[0024] In a possible design of the third aspect, if the conventional handover performed by the terminal device fails, the method further includes that the terminal device can generate a third report and report the third report to the first network device, where the third report includes one or more of the following information: time period information from receiving the CHO configuration information to receiving the first message, time period information from receiving the first message to the conventional handover failure, time period information from the conventional handover failure to connection recovery, time period information from the connection recovery to reporting the third report, time period information from the conventional handover failure to reporting the third report, time information at the conventional handover failure, location information of the terminal device at the conventional handover failure, and signal quality of the source cell and / or each candidate cell.

[0025] In a fourth aspect, an embodiment of the present application provides a communication apparatus, which has the functions of the terminal device in the first aspect or any possible design of the first aspect, or has the functions of the terminal device in the second aspect or any possible design of the second aspect, or has the functions of the terminal device in the third aspect or any possible design of the third aspect. The apparatus can be a terminal device or a chip included in a terminal device.

[0026] The functions of the communication apparatus described above can be implemented by hardware, or by hardware executing corresponding software, and the hardware or software includes one or more modules or units or means corresponding to the functions.

[0027] In one possible design, the apparatus includes a processing module and a transceiver module in its structure. The processing module is configured to support the apparatus to perform the corresponding functions of the terminal device in the first aspect or in any of the designs of the first aspect, or to perform the corresponding functions of the terminal device in the second aspect or in any of the designs of the second aspect, or to perform the corresponding functions of the terminal device in the third aspect or in any of the designs of the third aspect. The transceiver module is used to support the communication between the apparatus and other communication devices, e.g., the apparatus is a terminal device, and can receive the N CHO configuration information from the source network device. The apparatus can also include a storage module coupled with the processing module, which stores the necessary program instructions and data of the apparatus. As an example, the processing module can be a processor, the communication module can be a transceiver, and the storage module can be a memory, which can be integrated with the processor or can be separately arranged from the processor.

[0028] In another possible design, the apparatus includes a processor and can also include a memory. The processor is coupled with the memory and can be used to execute the computer program instructions stored in the memory, so as to enable the apparatus to perform the method in the first aspect or in any of the designs of the first aspect, or to perform the method in the second aspect or in any of the designs of the second aspect, or to perform the method in the third aspect or in any of the designs of the third aspect. Optionally, the apparatus also includes a communication interface, and the processor is coupled with the communication interface. When the apparatus is a terminal device, the communication interface can be a transceiver or an input / output interface; when the apparatus is a chip included in a terminal device, the communication interface can be an input / output interface of the chip. Optionally, the transceiver can be a transceiver circuit, and the input / output interface can be an input / output circuit.

[0029] In a fifth aspect, an embodiment of the present application provides a chip system, including: a processor, and a memory coupled with the processor, the memory being used to store a program or instructions, when the program or instructions are executed by the processor, enabling the chip system to implement the method in the first aspect or in any of the designs of the first aspect, or to implement the method in the second aspect or in any of the designs of the second aspect, or to implement the method in the third aspect or in any of the designs of the third aspect.

[0030] Optionally, the chip system also includes an interface circuit, which is used to interact code instructions to the processor.

[0031] Optionally, the processor in the chip system can be one or more, which can be implemented by hardware or software. When implemented by hardware, the processor can be a logic circuit, an integrated circuit, etc. When implemented by software, the processor can be a general-purpose processor, which is implemented by reading software code stored in a memory.

[0032] Optionally, the memory in the chip system can also be one or more. The memory can be integrated with the processor or arranged separately from the processor. For example, the memory can be a non-transient processor, such as a read-only memory (ROM), which can be integrated on the same chip as the processor or arranged on different chips respectively.

[0033] In a sixth aspect, an embodiment of the present application provides a computer readable storage medium, which stores a computer program or instructions, when the computer program or instructions are executed, causing a computer to execute the method in the first aspect or any possible design of the first aspect, or execute the method in the second aspect or any possible design of the second aspect, or execute the method in the third aspect or any possible design of the third aspect.

[0034] In a seventh aspect, an embodiment of the present application provides a computer program product, when a computer reads and executes the computer program product, causing the computer to execute the method in the first aspect or any possible design of the first aspect, or execute the method in the second aspect or any possible design of the second aspect, or execute the method in the third aspect or any possible design of the third aspect.

[0035] In an eighth aspect, an embodiment of the present application provides a communication system, which includes a source network device and a terminal device. Optionally, the communication system can further include at least one candidate target network device. Optionally, the communication system can further include a first network device, which can be the source network device or the target network device or a network device to which a reestablishment cell (i.e. a cell to which a connection is resumed) belongs or another network device. Optionally, the communication system can further include a core network device. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1a And Figure 1b A network architecture diagram of a satellite communication system suitable for an embodiment of the present application;

[0037] Figure 2 A diagram of a ground stationary cell formed by a mobile satellite;

[0038] Figure 3 A diagram of a ground mobile cell formed by a mobile satellite;

[0039] Figure 4 A schematic diagram of a handover procedure under a CHO mechanism is shown in FIG. 8.

[0040] Figure 5 A schematic diagram of a communication method provided by an embodiment of the present application is shown in FIG. 9.

[0041] Figure 6 A schematic diagram of a terminal device reporting a first report to a first network device in an embodiment of the present application is shown in FIG. 10.

[0042] Figure 7 A schematic diagram of another communication method provided by an embodiment of the present application is shown in FIG. 11.

[0043] Figure 8 A schematic diagram of another communication method provided by an embodiment of the present application is shown in FIG. 12.

[0044] Figure 9 A schematic diagram of a communication apparatus provided by an embodiment of the present application is shown in FIG. 13.

[0045] Figure 10 Another schematic diagram of a communication apparatus provided by an embodiment of the present application is shown in FIG. 14.

[0046] Figure 11 Another schematic diagram of a communication apparatus provided by an embodiment of the present application is shown in FIG. 15. DETAILED DESCRIPTION

[0047] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0048] The technical solutions of the embodiments of the present application can be applied to various communication systems, for example, a code division multiple access (CDMA) system, a wideband code division multiple access (WCDMA) system, a general packet radio service (GPRS), an LTE system, an LTE frequency division duplex (FDD) system, an LTE time division duplex (TDD), a universal mobile telecommunications system (UMTS), a 5th generation (5G) system or an NR system, or a future communication system or other similar communication system, etc.

[0049] The technical solutions provided by the embodiments of the present application can be applied to a non-terrestrial network (NTN) communication system, and can also be applied to a scenario in which an NTN and a terrestrial network (TN) are mixedly deployed. The NTN communication system can include a satellite communication system, a high altitude platform station (HAPS) communication system, or other non-ground communication systems.

[0050] The network architecture to which the present application is applied will be described in detail below taking the NTN communication system as a satellite communication system as an example.

[0051] Please refer to Figure 1a , a network architecture of a satellite communication system to which the embodiments of the present application are applicable, which includes a core network device 110, a radio access network device 120, a satellite 130, and at least one terminal device (such as a terminal device 140 shown in Figure 1a As an example, Figure 1a The core network device, the radio access network device, and the terminal device in

[0052] The radio access network device can communicate with the core network device through wireless or wired means. The core network device and the radio access network device can be independent and different physical devices, can be integrated into the same physical device with the functions of the core network device and the logical functions of the radio access network device, or can be a physical device integrated with part of the functions of the core network device and part of the functions of the radio access network device. It should be understood that the radio access network device mentioned in the embodiments of the present application can correspond to different devices in different communication systems, for example, in a 5G system, it corresponds to an access network device in 5G, such as gNB or ng-eNB, and in a 4G system, it corresponds to an access network device in 4G, such as eNB or en-gNB.

[0053] The communication between the radio access network device and the terminal device is through the satellite to forward signals, that is, the satellite can receive the signals of the radio access network device and forward the signals to the ground to form a satellite cell, thereby providing service coverage for the terminal devices on the ground. At this time, the satellite is equivalent to a relay node or a repeater, so this scenario can also be called a transparent form of satellite.

[0054] In the transparent forwarding form, the satellite cell can be ground-fixed (which can be denoted as "fixed cell") or can move on the ground along with the satellite (which can be denoted as "moving cell"). For the "fixed cell" scenario, the satellite cell is ground-fixed, which means that the coverage of the satellite cell on the ground is fixed, which can be fixed in a period of time or can be fixed permanently. For example, for a high-orbit satellite, since the satellite remains stationary relative to the ground, the satellite cell formed by the satellite is generally fixed relative to the ground. For a low-orbit satellite, since the satellite moves relative to the ground, the satellite can adjust the transmission angle of its antenna or other physical parameters to make the satellite cell formed by the satellite fixed relative to the ground.

[0055] For the "moving cell" scenario, the satellite cell moves along with the satellite, that is, when the satellite moves, the satellite cell also moves on the ground along with the satellite. Generally, the moving cell is caused because, along with the movement of the satellite, the satellite does not dynamically adjust the direction of the beam, thereby causing the projection of the beam generated by the satellite on the ground to move along with the movement of the satellite.

[0056] It should be noted that the embodiments of the present application do not specifically limit the existing scenario of the moving cell. When the satellite provides a service coverage area in the transparent forwarding form, a possible existing scenario of the moving cell can be that the satellite establishes a connection with an original radio access network device, along with the movement of the satellite, the cell under the original radio access network device forwarded by the satellite moves along with the satellite for a period of time, that is, the satellite maintains the connection with the original radio access network device for a period of time; at a certain moment, the connection between the satellite and the original radio access network device is disconnected due to a long distance, weak signal, or the like, the satellite is connected to a new radio access network device, and thereafter, the satellite starts to forward the signal of the new radio access network device to form a new satellite cell. It can be understood that although the satellite is running continuously, since the position of the radio access network device on the ground is unchanged, for the scenario of the moving cell, if the satellite forwards the signal of a certain radio access network device on the ground, the satellite cell formed by the satellite under the radio access network device will also move within a certain range along with the running of the satellite, but the moving range of the satellite cell is generally around the periphery of the radio access network device.

[0057] Reference is made to Figure 1b Another network architecture of the satellite communication system to which the embodiments of the present application are applicable is shown in FIG. 2, which includes a core network device 110, a satellite 130, and at least one terminal device (such as the terminal device 140 shown in FIG. 1). Figure 1b As an example, Figure 1b The core network device and the terminal device in FIG. 1 are located on the ground, and the satellite is located in the high sky.

[0058] As shown in FIG. 2, Figure 1aThe difference between the network architectures shown in FIGS. 1 and 2 is that Figure 1b In the network architecture shown in FIG. 2, a wireless access network device such as a base station can be deployed on the satellite. The satellite can generate a cell signal by itself and forward it to the ground to form a satellite cell, thereby providing a service coverage area for terminal devices on the ground. Therefore, this scenario can also be referred to as a regenerative form of satellite.

[0059] In the regenerative form, the satellite cell moves with the satellite, that is, when the satellite moves, the cell it generates also moves on the ground, and therefore can be referred to as a “moving cell”. Since the “moving cell” is generated by the satellite itself, the “moving cell” of the satellite can move on the ground along the orbit of the satellite. Generally, when a satellite moves away, a new satellite will move in to ensure continuous coverage as much as possible. The coverage area of the new satellite can be the same as or different from that of the previous satellite. It can be understood that due to the different running directions of the satellites, the directions of beam emission, and the beam emission capabilities, the ground coverage areas of two satellites can not necessarily be exactly the same.

[0060] Although Figure 1a and Figure 1b only one terminal device is shown in FIGS. 1 and 2, it should be understood that one wireless access network device or satellite or core network device can provide services for one or more terminal devices, and the number of core network devices, wireless access network devices, satellites, and terminal devices included in the satellite communication system is not limited in the embodiments of the present application. In addition, the terminal device can be fixed in position or movable, and the present application does not make any limitation.

[0061] The wireless access network device and the terminal device, and the terminal device and the terminal device, can communicate through licensed spectrum, unlicensed spectrum, or both licensed spectrum and unlicensed spectrum. The wireless access network device and the terminal device, and the terminal device and the terminal device, can communicate through spectrum below 6 gigahertz (GHz), spectrum above 6 GHz, or both spectrum below 6 GHz and spectrum above 6 GHz. The spectrum resources used between the wireless access network device and the terminal device are not limited in the embodiments of the present application.

[0062] As Figure 2The diagram illustrates a ground-stationary cell formed by a mobile satellite. It represents an ideal scenario where the ground cell is completely stationary, and when one satellite moves, another satellite completely covers the previous cell area. Ground-stationary cell mapping means that the cell's location on the ground remains fixed; mobile satellites can form these cells by adjusting their beams. It should be understood that when a satellite cell is a ground-stationary cell, the mobile satellite can provide service coverage through transparent relaying.

[0063] For example, at time T1: Cells 1 and 2 are covered by the beam of satellite 1, and cells 3 and 4 are covered by the beam of satellite 2. At time T2, although both satellites 1 and 2 have moved to the left, they can still adjust their beams to ensure coverage of cells 1, 2, 3, and 4. At time T3, compared to time T1, satellites 1 and 2 have moved a sufficient distance. Satellite 1 can no longer provide coverage for cell 2 by adjusting its beam, and satellite 2 can no longer provide coverage for cell 4 by adjusting its beam. At this point, satellite 2 can provide coverage for cell 2, and satellite 3 can provide coverage for cell 4.

[0064] like Figure 3 The diagram illustrates a ground mobile cell formed by a mobile satellite. In this example, the mapping method of the ground mobile cell means that the mobile satellite does not dynamically adjust its beam direction; the beam generated by the base station moves on the ground as the satellite / base station moves. It should be understood that when the satellite cell is a ground mobile cell, the mobile satellite can provide service coverage through transparent forwarding or regeneration.

[0065] For example, at time T1, an area is covered by cells 1 and 2 formed by satellite 1, and cells 3 and 4 formed by satellite 2. As cells 1, 2, 3, and 4 move with satellites 1 and 2, at time T3, this area becomes covered by cell 2 formed by satellite 1, cells 3 and 4 formed by satellite 2, and cell 5 formed by the newly moved satellite 3.

[0066] The network architecture and business scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of communication network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0067] The following explanations of some terms used in the embodiments of this application are provided to facilitate understanding by those skilled in the art.

[0068] 1) The terminal device involved in the embodiments of the present application is a device with wireless transceiving function, which can be deployed on land, including indoor or outdoor, handheld, wearable or vehicle-mounted; can also be deployed on water surface (such as ships, etc.); can also be deployed in the air (such as airplanes, balloons and satellites, etc. The terminal device can communicate with the core network through the radio access network (RAN), and exchange voice and / or data with the RAN. The terminal device can be a mobile phone, a tablet computer (Pad), a computer with wireless transceiving function, a mobile internet device (MID), a wearable device, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, etc. The embodiments of the present application do not limit the application scenarios. The terminal device can also be called user equipment (UE), mobile station and remote station, etc. The embodiments of the present application do not limit the specific technology, device form and name of the terminal device.

[0069] As an example but not limitation, in the embodiments of the present application, the terminal device can also be a wearable device. The wearable device can also be called a smart wearable device or a smart wearable device, etc. It is a general term of devices that are designed and developed by applying wearable technology to daily wear, such as glasses, gloves, watches, clothing and shoes, etc. Wearable device is a portable device that can be directly worn on the body or integrated into the user's clothes or accessories. Wearable device is not only a hardware device, but also a powerful function realized through software support and data interaction, cloud interaction. The general wearable smart device includes full function, large size, which can realize complete or partial function without relying on smart phone, such as smart watch or smart glasses, etc. And only focus on a certain application function, need to cooperate with other devices such as smart phone, such as various types of smart wristbands, smart helmets, smart jewelry, etc.

[0070] The terminal device in the embodiments of the present application can also be a vehicle-mounted module, a vehicle-mounted module group, a vehicle-mounted component, a vehicle-mounted chip or a vehicle-mounted unit built in a vehicle as one or more components or units, and the vehicle can implement the method of the present application through the built-in vehicle-mounted module, vehicle-mounted module group, vehicle-mounted component, vehicle-mounted chip or vehicle-mounted unit.

[0071] 2) The radio access network device involved in the embodiments of the present application is a device in a network for accessing a terminal device to a wireless network. The radio access network device can be a node in a radio access network, also referred to as a base station, and also referred to as a RAN node. In the present application, the radio access network device refers to a radio access network device deployed on the ground or a satellite, and in the following description, the radio access network device can be referred to as an access network device or a network device.

[0072] The access network device can include an evolved NodeB (NodeB or eNB or e-NodeB, evolutional Node B) in an LTE system or an evolved LTE system (LTE-Advanced, LTE-A), such as a conventional macro base station eNB and a micro base station eNB in a heterogeneous network scenario, or can include a next generation NodeB (gNB) in a 5G system or an NR system, or can include a radio network controller (RNC), a NodeB (NB), a base station controller (BSC), a base transceiver station (BTS), a transmission reception point (TRP), a home base station (for example, a home evolved NodeB, or a home NodeB, HNB), a baseband unit (BBU), a baseband pool BBU pool, or a wireless fidelity (WiFi) access point (AP), an integrated access and backhaul (IAB) node, or the like, or can include a centralized unit (CU) and / or a distributed unit (DU) in a cloud radio access network (CloudRAN) system, and the embodiments of the present application are not limited.

[0073] For example, in a network structure, a network device can be a CU node, or a DU node, or an access network device including a CU node and a DU node. Further, the CU node can be divided into a control plane (CU-CP) and a user plane (CU-UP), wherein the CU-CP is responsible for control plane functions, mainly including a radio resource control (RRC) and a packet data convergence protocol (PDCP)-C, and the PDCP-C is mainly responsible for encryption and decryption of control plane data, integrity protection, data transmission, etc. The CU-UP is responsible for user plane functions, mainly including an SDAP and a PDCP-U, the SDAP is mainly responsible for processing data of a core network and mapping a flow to a bearer, and the PDCP-U is mainly responsible for encryption and decryption of a data plane, integrity protection, header compression, sequence number maintenance, data transmission, etc. The CU-CP and the CU-UP can be connected through an E1 interface. The CU-CP represents the CU to connect with a core network through an Ng interface, and to connect with a DU through an F1-C (control plane). The CU-UP is connected with the DU through an F1-U (user plane). Of course, there is also a possible implementation that the PDCP-C is also in the CU-UP.

[0074] 3) The core network device involved in the embodiments of the present application refers to a device in a core network (CN) that provides service support for a terminal device. Currently, some examples of core network devices include: an access and mobility management function (AMF) entity, a session management function (SMF) entity, a user plane function (UPF) entity, etc. Among them, the AMF entity is used to be responsible for access management and mobility management of the terminal device; the SMF entity is used to be responsible for session management, such as session establishment of a user, etc.; and the UPF entity is a functional entity of a user plane, mainly used to be responsible for connecting an external network. It should be noted that the entity in the present application can also be referred to as a network element or a functional entity, that is, the AMF entity can also be referred to as an AMF network element or an AMF functional entity, and the SMF entity can also be referred to as an SMF network element or an SMF functional entity. In the following description of the present application, the core network device can refer to the AMF.

[0075] 4) The satellite referred to in the embodiments of the present application refers to a network device located on a satellite. For ease of description, the network device on the satellite can be referred to as a satellite. The satellite can be a low earth orbiting (LEO) satellite or a medium earth orbiting satellite or other network device located in high altitude and moving. Generally, according to the orbital height of the satellite, the satellites in the satellite communication system can be divided into three categories: geostationary earth orbiting (GEO) satellites, low earth orbiting (LEO) satellites, and medium earth orbiting satellites. Among them, the high orbit satellite can also be called the stationary satellite. The running speed of the high orbit satellite is the same as the rotation speed of the earth, so the high orbit satellite remains stationary relative to the ground. Correspondingly, the satellite cell formed by the high orbit satellite is also stationary. The low orbit satellite can also be called the near-earth orbit satellite. The low orbit satellite moves relatively fast relative to the ground, so the satellite cell formed by the low orbit satellite can move with the satellite. The medium orbit satellite refers to a satellite located between the high orbit satellite and the low orbit satellite.

[0076] 5) It should be noted that the terms "system" and "network" in the embodiments of the present application can be used interchangeably. "Multiple" means two or more. In view of this, "multiple" can also be understood as "at least two" in the embodiments of the present application. "At least one" can be understood as one or more, for example, as one, two or more. For example, including at least one means including one, two or more, and does not limit which ones are included. For example, including at least one of A, B and C means that A, B, C, A and B, A and C, B and C, or A and B and C can be included. Similarly, the understanding of "at least one" and the like is also similar. "And / or" describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases of A alone, A and B together, and B alone. In addition, the character " / ", unless otherwise specified, generally represents an "or" relationship between the associated objects before and after it.

[0077] Unless otherwise stated, the ordinal numbers "first", "second", and the like mentioned in the embodiments of the present application are used to distinguish a plurality of objects, and are not used to limit the order, time sequence, priority or importance of the plurality of objects, and the description of "first", "second" does not necessarily mean that the objects are different.

[0078] The cell referred to in the embodiments of the present application can be an NTN cell, for example, a satellite cell.

[0079] The embodiments of the present application can also be applied to a scenario of cell switching. The terminal device can be switched from a source network device to a target network device due to movement of a location, change of a service, change of network coverage, or other reasons. The source network device refers to a network device accessed by the terminal device before performing the switching, or a network device providing service for the terminal device before the switching. The target network device refers to a network device to which the terminal device needs to be switched, or a network device accessed by the terminal device after successfully performing the switching, or a network device providing service for the terminal device after the switching is successful. Correspondingly, the source cell refers to a cell accessed by the terminal device before performing the switching, the source cell is a cell covered by the source network device, or the source cell is a cell governed by the source network device, or the source cell belongs to the source network device. The target cell refers to a cell accessed by the terminal device after performing the switching, the target cell is a cell covered by the target network device, or the target cell is a cell governed by the target network device, or the target cell belongs to the target network device.

[0080] To effectively improve the switching reliability, the above cell switching can be CHO. In the CHO mechanism, the network (such as the source network device) can configure one or more candidate cells for the terminal device, and the candidate cell can also be referred to as a candidate target cell. If the network configures multiple candidate cells for the terminal device, the network can send CHO configuration information corresponding to the multiple candidate cells to the terminal device through one or more RRC messages. The above RRC message can be a newly defined message (such as CondRRCReconfiguration, or other naming / expressions, which are not limited) or reuse an existing RRC message (such as an RRC reconfiguration message).

[0081] The source network device can send an RRC message to the terminal device when the source link signal quality is good, and the RRC message can include CHO configuration information corresponding to at least one candidate cell. The CHO configuration information corresponding to one candidate cell can include CHO execution condition information and related information of the candidate cell.

[0082] The related information of the candidate cell can include one or more of the following information: a cell radio network temporary identifier (C-RNTI) allocated to the terminal device by the candidate cell, random access channel (RACH) resource information required to access the candidate cell, index information corresponding to the candidate cell (such as a measurement identifier measID corresponding to the cell and / or a CHO reconfiguration identifier CondReconfigId corresponding to the cell), a cell global identifier (CGI) of the candidate cell, a physical cell identifier (PCI) of the candidate cell, frequency information corresponding to the candidate cell, physical layer configuration parameters corresponding to the candidate cell, media access control (MAC) layer configuration parameters, radio link control (RLC) layer configuration parameters, packet data convergence (PDCP) layer configuration parameters, service data adaptation protocol (SDAP) layer configuration parameters, RRC layer configuration parameters, and the like. The frequency information of the candidate cell can include one or more of the following: an absolute frequency of a synchronization signal block (SSB) (such as absoluteFrequencySSB), an absolute frequency position of a reference resource module (common RB0) (such as absoluteFrequencyPointA), a frequency bandwidth list (such as frequencyBandList), a subcarrier spacing (SCS)-specific carrier list (such as scs-SpecificCarrierList).

[0083] The CHO execution condition information is used to indicate a CHO execution condition corresponding to the candidate cell, which can also be referred to as a CHO trigger condition. Taking a CHO execution condition based on the signal quality of a cell as an example (i.e., the trigger quantity in the CHO execution condition is the signal quality of a cell), the CHO execution condition information can include a CHO execution event type and a corresponding threshold value, and the CHO execution event type can include event A3, event A4, event A5, event B1, event B2, or other execution event types.

[0084] One candidate cell can be configured with one or more CHO execution conditions. For example, one candidate cell can be configured with one execution event type, but configured with at most two different trigger quantities, and at least two different threshold values for each trigger quantity, the trigger quantity can include one or more of reference signal received power (RSRP), reference signal received quality (RSRQ), signal to interference plus noise ratio (SINR), etc. Alternatively, one candidate cell can be configured with at least two different execution event types, and threshold values corresponding to each execution event type. The different candidate cells can correspond to the same or different execution event types and / or threshold values corresponding to the execution event types, which are not limited.

[0085] It can be understood that the source cell, the target cell or the candidate cell in the embodiments of the present application can be the NTN cell, such as the satellite cell, introduced above. Alternatively, the service coverage area of the source cell, the target cell or the candidate cell can be divided into multiple areas, and different areas can correspond to different PLMNs and / or different AMFs, forming different virtual cells.

[0086] Figure 4An example is shown to illustrate the handover procedure under CHO mechanism, in which the source base station configures two candidate cells for the UE, and the two candidate cells are managed by candidate target base station 1 and candidate target base station 2 respectively. The handover procedure can include: in step S401, the source base station issues a measurement configuration to the UE, and accordingly receives a measurement report reported by the UE in step S402. In steps S403-a and S404-a, the source base station performs CHO handover preparation with the candidate target base station 1, and can send a handover request message to the candidate target base station 1 and receive a handover request acknowledgement message from the candidate target base station 1, which can include CHO configuration information of the candidate target cell 1. In steps S403-b and S404-b, the source base station performs CHO handover preparation with the candidate target base station 2, and can send a handover request message to the candidate target base station 2 and receive a handover request acknowledgement message from the candidate target base station 2, which can include CHO configuration information of the candidate cell 2. In step S405, the source base station can send an RRC message to the UE, which includes CHO configuration information corresponding to the candidate cell 1 and the candidate cell 2 respectively. Further, in step S406, after receiving the RRC message, the UE can determine whether the CHO execution conditions of the candidate cell 1 and the candidate cell 2 are met according to the CHO configuration information of the candidate cell 1 and the candidate cell 2 respectively, and take the cell that meets the CHO execution condition as the target cell. Subsequently, the UE can initiate random access to the base station to which the target cell belongs, so as to access the target cell. Assuming that the UE determines the candidate cell 1 as the target cell, in step S407, the UE can perform a random access process with the candidate target base station 1 (i.e. the target base station), and after the random access process succeeds, in step S408, the UE can send an RRC reconfiguration completion message to the candidate target base station 1 (i.e. the target base station). It can be understood that after the UE determines the candidate cell 1 as the target cell, the candidate target base station can also be referred to as the target base station. It should be noted that Figure 4 The CHO procedure can have other variations, which are not limited in the present application. Figure 4 Each step in the above example can be optional, and the execution order between steps can be changed.

[0087] Specifically, the UE can determine whether the CHO execution condition is met according to the CHO configuration information. In one example, assuming that the CHO execution event type configured for the candidate cell 1 is an A3 event, the trigger quantity is the signal quality of the cell, and the corresponding threshold value is a first threshold value, when the cell signal quality of the candidate cell 1 is higher than the cell signal quality of the serving cell by the first threshold value, it can be considered that the candidate cell 1 meets the CHO execution condition, and the candidate cell 1 can be determined as the target cell. It should be noted that the signal quality can include one or more of RSRP, RSRQ and SINR, for example, the signal quality can include RSRP and RSRQ, or RSRP and SINR, or other parameters, and is not limited. When multiple parameters are included in the signal quality, each of them can be considered as a separate trigger quantity, for example, when the signal quality includes RSRP and RSRQ, RSRP can be considered as a trigger quantity and RSRQ as another trigger quantity. For different trigger quantities, the corresponding first threshold value can be the same or different, and is not limited. Specifically, for the candidate cell 1, the A3 event is configured, and two trigger quantities are configured, which are RSRP and RSRQ respectively, the first threshold value corresponding to the configured RSRP is E, and the first threshold value corresponding to the configured RSRQ is F, when the RSRP of the candidate cell 1 is higher than the RSRP of the serving cell by E, and the RSRQ of the candidate cell 1 is higher than the RSRQ of the serving cell by F, it can be considered that the candidate cell 1 meets the CHO execution condition, and the candidate cell 1 can be determined as the target cell.

[0088] In another example, assuming that the CHO execution event type configured for the candidate cell 1 is an A5 event, the trigger quantity is the signal quality of the cell, and the corresponding threshold value is a second threshold value and a third threshold value, when the cell signal quality of the candidate cell 1 is higher than the second threshold value, and the cell signal quality of the serving cell is lower than the third threshold value, it can be considered that the candidate cell 1 meets the CHO execution condition, and the candidate cell 1 can be determined as the target cell.

[0089] In another example, assuming that the CHO execution event type configured for the candidate cell 1 is an A3 event and an A5 event, the trigger quantity configured for the A3 event is RSRP, and the corresponding threshold value configured for the A3 event is a first threshold value; the trigger quantity configured for the A5 event is RSRQ, and the corresponding threshold value configured for the A5 event is a second threshold value and a third threshold value, when the RSRP of the candidate cell 1 is higher than the RSRP of the serving cell by the first threshold value, and when the RSRQ of the candidate cell 1 is higher than the second threshold value, and the RSRQ of the serving cell is lower than the third threshold value, it can be considered that the candidate cell 1 meets the CHO execution condition, and the candidate cell 1 can be determined as the target cell.

[0090] It should be noted that the above examples are only illustrative, and the embodiments of the present application are not limited thereto.

[0091] Considering that NTN communication has significant propagation delay, it is possible to cause handover failure, so the CHO mechanism has obvious gain in NTN communication system. In NTN communication system, since the moving track of satellite is regular, the network device can know the ephemeris diagram, for example, which cell / base station provides service for the terminal device at a specific geographic location, or which cell / base station provides service for the terminal device in a specific time period. Therefore, the CHO mechanism in NTN communication system can introduce a criterion for judging whether the CHO execution condition is met according to the location information and time information.

[0092] Specifically, the CHO mechanism in NTN communication system can have the following three CHO execution condition information:

[0093] 1) Based on signal quality. The CHO execution condition information can include CHO execution event type and corresponding threshold value. For details, please refer to the relevant introduction of CHO execution condition information in the foregoing.

[0094] 2) Based on location information. The CHO execution condition information can be geographic location information. For example, in an embodiment, the geographic location information can be the geographic location information of the terminal device on the ground, for example, the CHO execution condition information can include latitude and longitude values, which can be used to determine a certain area or a fixed point, when the geographic location of the terminal device meets the latitude and longitude requirement, such as when the terminal device moves to the area indicated by the latitude and longitude value or the fixed point position, the terminal device can perform handover. Or, in another embodiment, the geographic location information can be the distance between the terminal device and the satellite, for example, the CHO execution condition information can include a distance threshold value, when the distance between the terminal device and the satellite reaches the threshold value, the UE can perform handover. Or, in another embodiment, the geographic location information can be global positioning system (GPS) information or timing advance (TA) or other information, in this embodiment, one candidate cell can correspond to one or more CHO execution condition information, and the candidate cell has corresponding related information (i.e. the related information of the candidate cell), the CHO execution condition information corresponding to different candidate cells can be the same or different, which is not limited.

[0095] 3) Time / timer information. The CHO execution condition information can be time information. For example, in an embodiment, the CHO execution condition information can be an absolute time value, such as a specific time value (e.g., 12:00 of coordinated universal time (UTC)) or a specific time period value (e.g., UTC 12:00-UTC 13:00), i.e., when the absolute time arrives, the terminal device can perform handover. Alternatively, in another embodiment, the CHO execution condition information can be a relative time value, such as a valid duration of a timer, i.e., after the terminal device receives the RRC message containing the CHO configuration information, the terminal device starts the timer, and when the valid duration of the timer arrives, the terminal device can perform handover. In this embodiment, one candidate cell can correspond to one or more CHO execution condition information, and the candidate cell has corresponding related information (i.e., the related information of the candidate cell), and the CHO execution condition information corresponding to different candidate cells can be the same or different.

[0096] When the network performs CHO configuration, at least one of the above-mentioned three CHO execution condition information can be configured as the CHO execution condition information. For example, the CHO execution event type and the corresponding threshold value, and the absolute time value can be configured as the CHO execution condition information, and when the absolute time arrives and the signal quality of the corresponding candidate cell meets the condition, the terminal device can determine the candidate cell as the target cell and perform handover.

[0097] It can be understood that in the embodiments of the present application, the terminal device and / or the network device can perform part or all of the steps in the embodiments of the present application, and these steps or operations are only examples, and the embodiments of the present application can also perform other operations or various modifications of the operations. In addition, each step can be executed in a different order from the order presented in the embodiments of the present application, and it is possible that not all the operations in the embodiments of the present application are executed.

[0098] For reference Figure 5 A flowchart of a communication method according to an embodiment of the present application is provided, and the method comprises:

[0099] In step S501, the terminal device receives N CHO configuration information from the source network device, each CHO configuration information indicating the CHO execution condition of the candidate cell corresponding to the CHO configuration information, and the CHO execution condition is based on the location information and / or the time information and / or the signal quality information, and N is an integer greater than 1.

[0100] In the embodiments of the present application, the source network device can configure one or more candidate cells for the terminal device, and can provide one or more CHO configuration information corresponding to each candidate cell to the terminal device. For example, if a candidate cell is a cell covering a geographical area of a country or a service area of an operator, or if a candidate cell is a cell supporting one or more public land mobile networks (PLMNs) and / or AMFs, the candidate cell can correspond to one CHO configuration information. If a candidate cell is a cell covering a geographical area of multiple countries or a service area of multiple operators, or if a candidate cell is a cell supporting multiple PLMNs and / or AMFs, the candidate cell can correspond to multiple CHO configuration information, and further, different PLMNs and / or AMFs in the candidate cell can correspond to different CHO configuration information. Therefore, if the terminal device receives N CHO configuration information from the source network device, the number M of candidate cells configured by the source network device for the terminal device can be less than or equal to N, and M is a positive integer.

[0101] Specifically, each of the N CHO configuration information can include CHO execution condition information, which is used to indicate the CHO execution condition of the corresponding candidate cell. In the embodiments of the present application, the CHO execution condition is based on location information and / or time information and / or signal quality information, that is, the CHO execution condition information can include one or more of location information, time information or signal quality information.

[0102] Optionally, the source network device can send the N CHO configuration information to the terminal device through one or more RRC messages, which is not limited.

[0103] In step S502, the terminal device occurs radio link failure (RLF) in the source cell before the CHO execution condition indicated in any of the N CHO configuration information is satisfied.

[0104] In the embodiments of the present application, the CHO execution condition is satisfied, which can also be understood as the CHO execution condition is triggered. If the CHO condition of a certain candidate cell is triggered, it means that the candidate cell will be determined as a target cell, and the terminal device can try to access the candidate cell.

[0105] In this case, the step S502 can also mean that the terminal device determines that the RLF occurs in the source cell before the target cell is determined from the candidate cells corresponding to the N CHO configuration information. It can be understood that before the target cell is determined from the candidate cells corresponding to the N CHO configuration information, the CHO execution condition indicated by any one of the N CHO configuration information is not triggered, or the CHO execution condition of any one of the candidate cells is not triggered.

[0106] The step S503 includes determining, by the terminal device, a first cell to be accessed according to the N CHO configuration information, a current location of the terminal device, and / or a current time, and / or a current signal quality.

[0107] In this embodiment, the current location of the terminal device can be a location of the terminal device when the RLF occurs in the source cell. The current location of the terminal device can be a geographical location such as longitude and latitude values, or a relative location such as a distance between the terminal device and a satellite, and is not limited. Correspondingly, the current time can be a time point when the RLF occurs in the source cell. The current signal quality can be a signal quality of each of the candidate cells, the source cell, and one or more of other cells when the RLF occurs in the source cell.

[0108] Specifically, if the current location of the terminal device, and / or the current time, and / or the current signal quality match one of the N CHO configuration information, the terminal device can determine that the first cell is a first candidate cell corresponding to the matched first CHO configuration information. Further, the terminal device can access the first cell according to the first CHO configuration information.

[0109] If the current location of the terminal device, and / or the current time, and / or the current signal quality match a plurality of CHO configuration information of the N CHO configuration information, the terminal device can select one of the candidate cells corresponding to the matched plurality of CHO configuration information as the first cell, and then access the first cell according to the corresponding CHO configuration information. It should be noted that in this case, which candidate cell is selected by the terminal device as the first cell, or which candidate cell is accessed by the terminal device, can be based on the terminal device implementation, and is not limited by the present application. For example, the terminal device can determine a first CHO configuration information from the plurality of CHO configuration information according to a signal quality of the candidate cells corresponding to the plurality of CHO configuration information respectively. The first candidate cell corresponding to the first CHO configuration information can be one of the candidate cells corresponding to the N CHO configuration information with the best signal quality. The signal quality can include one or more of RSRP, RSRQ, and SINR, or can also include other parameters, and is not limited.

[0110] Optionally, the first CHO configuration information can comprise the related information of the first candidate cell, and the terminal device can access the first candidate cell by using the related information of the first candidate cell. The specific content of the related information of the candidate cell can refer to the description in the foregoing description, and will not be described here.

[0111] If the current location and / or the current time and / or the current signal quality of the terminal device does not match any of the N CHO configuration information, the terminal device can determine that the first cell is not a candidate cell. The terminal device can determine a cell other than the candidate cells corresponding to the N CHO configuration information as the first cell, and perform re-establishment in the first cell. The first cell can also be the source cell, or a cell other than the source cell and the candidate cell, and is not limited.

[0112] It should be noted that in the embodiments of the present application, the current location and / or the current time and / or the current signal quality of the terminal device matches one or more of the N CHO configuration information, which can also be understood as that the current location and / or the current time and / or the current signal quality of the terminal device meets one or more of the N CHO configuration information. Wherein, the current location of the terminal device matches a certain CHO configuration information specifically can mean that the current location of the terminal device is within the cell range of the candidate cell corresponding to the CHO configuration information. Optionally, if the CHO execution condition is a location-based CHO execution condition, the CHO execution condition information in the CHO configuration information can comprise location information, and the location information is used to indicate the cell range of the candidate cell corresponding to the CHO configuration information. The location information can be area information, which is used to indicate a geographical area on the ground, for example, represented by longitude and latitude values and a radius, so if the current location of the terminal device is within the range of the geographical area indicated by the area information, it can be represented that the current location of the terminal device matches the CHO configuration information. Alternatively, the location information can also be distance information, which is used to indicate the interval range or threshold value of the distance between the terminal device and the satellite, so if the current distance between the terminal device and the satellite is within the interval range of the distance indicated by the distance information, or reaches the threshold value of the distance indicated by the distance information, it can be represented that the current location of the terminal device matches the CHO configuration information. It can be understood that the current location of the terminal device does not match a certain CHO configuration information means that the current location of the terminal device is not within the cell range of the candidate cell corresponding to the CHO configuration information.

[0113] The current time matches a certain CHO configuration information specifically can mean that the current time is within the time range of the candidate cell corresponding to the CHO configuration information. Optionally, if the CHO execution condition is a time-based CHO execution condition, the CHO execution condition information in the CHO configuration information can include time information, which is used to indicate the time range of the candidate cell corresponding to the CHO configuration information. The time information can be time period information or time interval information, which can be represented by specific time values of the start time and end time of the time period, for example. Thus, if the current time is within the time range indicated by the time period information, it can be considered that the current time matches the CHO configuration information. Alternatively, the time information can also be timer information, which can be represented by the effective duration of the timer. The timer is started when the terminal device receives the CHO configuration information. Thus, if the timer indicated by the time information is triggered at the current time, i.e., reaches the effective duration, it can be considered that the current time matches the CHO configuration information.

[0114] The current signal quality matches a certain CHO configuration information specifically can mean that the current signal quality is within the signal quality range of the cell corresponding to the CHO configuration information. Optionally, if the CHO execution condition is a signal quality-based CHO execution condition, the CHO execution condition information in the CHO configuration information can include signal quality information, which is used to indicate the signal quality range of the candidate cell corresponding to the CHO configuration information. For example, the signal quality information can indicate a signal quality threshold. If the current signal quality of the terminal device is greater than the signal quality threshold indicated by the signal quality information, it can be considered that the current signal quality matches the CHO configuration information.

[0115] It should be noted that if the CHO execution condition is a CHO execution condition based on multiple information such as location information, time information, and signal quality information, the terminal device can respectively judge whether the current location of the terminal device matches the location information in the CHO configuration information, whether the current time matches the time information in the CHO configuration information, and whether the current signal quality matches the signal quality in the CHO configuration information when judging whether it matches a certain CHO configuration information. Moreover, the order of the judgment between the current location of the terminal device, the current time, and the current signal quality is not limited in the embodiments of the present application.

[0116] Exemplarily, if the CHO execution condition is a CHO execution condition based on location information and time information, in one possible implementation, if the current location of the terminal device matches the location information in the CHO configuration information, and the current time matches the time information in the CHO configuration information, it can be considered that the terminal device matches the CHO configuration information. In this implementation, it is referred to that the terminal device needs to determine which parameters are consistent with the CHO execution condition information, and the relationship between different parameters (i.e., the current location of the terminal device and the current time) is and. It can be understood that, since the CHO execution condition is based on location information and time information, it is necessary to determine whether the current location of the terminal device and the current time match the CHO configuration information. When the CHO execution condition is a CHO execution condition based on location information and signal quality information, or a CHO execution condition based on time information and signal quality information, or a CHO execution condition based on location information, time information and signal quality information, it is similar. Alternatively, in another possible implementation, if any of the current location of the terminal device and the current time matches the corresponding location information or time information in the CHO configuration information, it can be considered that the terminal device matches the CHO configuration information. In this implementation, it is referred to that the terminal device needs to determine which parameters are consistent with the CHO execution condition information, but the relationship between different parameters (i.e., the current location of the terminal device and the current time) is or.

[0117] According to the above content, in this embodiment, before the terminal device meets the CHO execution condition indicated by any of the N CHO configuration information, or before the terminal device determines the target cell to be switched according to the N CHO configuration information, when the radio link failure occurs in the source cell, the terminal device can select a cell to be accessed according to the N CHO configuration information, the current location and / or the current time and / or the signal quality information of the terminal device. The cell to be accessed can also be understood as a cell to be connected, or a cell to be re-established, etc. If the current location and / or the current time and / or the current signal quality of the terminal device match one or more of the N CHO configuration information, the terminal device can select a candidate cell configured by the source network device to access. Specifically, the terminal device can select a first candidate cell corresponding to a first CHO configuration information in the one or more CHO configuration information that matches the terminal device as a first cell, and access the first candidate cell according to the related information of the first candidate cell in the first CHO configuration information, such as the C-RNTI allocated to the terminal device by the first candidate cell, the RACH resource information required to access the first candidate cell, etc.

[0118] If the current location and / or current time and / or current signal quality of the terminal device does not match the N CHO configuration information, the terminal device can select other cell access instead of the candidate cell configured by the source network device. That is, in this case, the terminal device can determine other cell (i.e. non-candidate cell) as the first cell to be accessed, and perform re-establishment in the first cell.

[0119] Therefore, the above technical solution provides a CHO failure processing mechanism when the terminal device has a radio link failure in the source cell before the CHO execution condition is met in the scenario where the CHO execution condition is based on location information and / or time information and / or signal quality information. The terminal device can determine the cell to resume connection according to the location, time, signal quality when the radio link failure occurs and the CHO configuration information, so that the terminal device can perform reasonable processing after the radio link failure, reduce the interruption delay caused by the radio link failure, and improve the system performance.

[0120] In one specific example, the source network device can provide three CHO configuration information for the terminal device, which are CHO configuration information A, CHO configuration information B and CHO configuration information C. Specifically, the CHO configuration information A includes area information A and related information A, where the area information A is used to indicate the CHO execution condition of the candidate cell A corresponding to the CHO configuration information A, for example, the area information A can be {(longitude value 1, latitude value 1), radius 1 or diameter 1}, indicating that the corresponding CHO execution condition is satisfied when the terminal device is located within the cell range of the candidate cell A identified by {(longitude value 1, latitude value 1), radius 1 or diameter 1}, and the related information A is used to indicate the related information of the candidate cell A corresponding to the CHO configuration information A, such as the C-RNTI allocated by the candidate cell A to the terminal device, the RACH resource information required for accessing the candidate cell A, etc. The CHO configuration information B includes area information B and related information B, where the area information B is used to indicate the CHO execution condition of the candidate cell B corresponding to the CHO configuration information B, for example, the area information B can be {(longitude value 2, latitude value 2), radius 2 or diameter 2}, indicating that the corresponding CHO execution condition is satisfied when the terminal device is located within the cell range of the candidate cell B identified by {(longitude value 2, latitude value 2), radius 2 or diameter 2}, and the related information B is used to indicate the related information of the candidate cell B corresponding to the CHO configuration information B. The CHO configuration information C includes area information C and related information C, where the area information C is used to indicate the CHO execution condition of the candidate cell C corresponding to the CHO configuration information C, which can be represented as {(longitude value 3, latitude value 3), radius 3 or diameter 3}, indicating that the corresponding CHO execution condition is satisfied when the terminal device is located within the cell range of the candidate cell C identified by {(longitude value 3, latitude value 3), radius 3 or diameter 3}, and the related information C is used to indicate the related information of the candidate cell C corresponding to the CHO configuration information C. In this way, after the terminal device receives the above-mentioned CHO configuration information A, CHO configuration information B and CHO configuration information C, if the RLF occurs in the source cell before each CHO execution condition is satisfied, in this case, if the terminal device is located within the cell range of the candidate cell B indicated by the area information B at this time, the terminal device can access the candidate cell B using the related information B. If the terminal device is not located within the cell range of the candidate cell A indicated by the area information A, nor within the cell range of the candidate cell B indicated by the area information B, nor within the cell range of the candidate cell C indicated by the area information C, the terminal device can perform re-establishment in other cells.

[0121] Optionally, the terminal device can also record information related to the connection failure after the RLF occurs in the source cell, generate a first report, and report the first report to the first network device. The first report can include one or more of the following information:

[0122] 1) failedPcellID: cell information of a connection failure cell, or cell information of a cell in which the terminal device detects RLF.

[0123] The cell information can include a cell global identifier (CGI) and / or a physical cell identifier (PCI) and frequency information. The CGI can include a PLMN ID and a cell ID. Optionally, the cell information can further include at least one of a tracking area code (TAC) and a RAN area code (RANAC), which will not be described below.

[0124] 2) connectionFailureType: connection failure type, such as RLF.

[0125] 3) previousPCellId: cell information of a source cell.

[0126] 4) cell information of a cell in which the terminal device resumes connection after RLF of the source cell, or cell information of a cell accessed by the terminal device after RLF of the source cell.

[0127] 5) C-RNTI allocated to the terminal device by the source cell.

[0128] 6) timeconnFailure: time information when RLF of the source cell occurs, i.e., time when RLF of the source cell occurs, which can also be referred to as connection failure time. For example, it can be an absolute time value (such as UTC) when RLF of the source cell occurs, or a relative time value (such as a time period from the last time the terminal device receives an RRC reconfiguration message to when RLF of the source cell occurs).

[0129] 7) time period information from RLF of the source cell to connection recovery.

[0130] 8) time period information from RLF of the source cell to reporting of the first report, and / or time period information from connection recovery of the terminal device to reporting of the first report.

[0131] 9) location information of the terminal device when RLF of the source cell occurs. For example, it can be an absolute location (such as latitude and longitude values) of the terminal device, or a relative location (such as a distance between the terminal device and a satellite), which is not limited.

[0132] 10) signal quality of the source cell and / or each candidate cell. For example, the signal quality of the source cell and / or each candidate cell at one or more time nodes, such as when the terminal device receives the CHO configuration information, when the RLF of the source cell occurs, when the connection of the terminal device is recovered, when the terminal device reports the first report, and the like. The signal quality can include the signal quality of the cell and / or the signal quality of at least one beam belonging to the cell, and the signal quality can include one or more of RSRP, RSRQ, and SINR, or a measurement result obtained based on SSB and / or channel state information-reference signal (CSI-RS) radio resource management (RRM) measurement, which will not be described below.

[0133] It should be noted that the first network device can be a network device to which the source cell belongs (i.e., a source network device), a network device to which the candidate cell belongs (i.e., a candidate target network device), a network device to which the recovered cell or the re-established cell belongs (i.e., a network device to which the first cell belongs), or other network devices such as a network element of a core network, and is not limited.

[0134] Specifically, the process in which the terminal device reports the first report to the first network device can be as shown in Figure 6 In step S601, the terminal device can send first indication information to the first network device, where the first indication information indicates that the terminal device records the first report including the connection failure related information, or the first indication information can also be understood as indicating that the terminal device records / preserves the connection failure related information. The connection failure related information can be one or more of the information included in the first report listed above. Further, in step S602, the first network device can send a first request message to the terminal device, where the first request message is used to request the terminal device to report the first report. Optionally, the first request message can be a UE information request (UEinformationRequest) message. In step S603, the terminal device sends a first response message to the first network device, where the first response message includes the first report, and step S603 can also be understood as the terminal device sending the connection failure related information recorded by the terminal device to the first network device. Optionally, the first response message can be a UE information response (UEinformationResponse) message, and the UE information response message includes the connection failure related information recorded by the terminal device.

[0135] Optionally, if the first network device is not the source network device, the first network device can further send part or all of the information in the first report to the source network device after receiving the first report. Further, the source network device can perform adjustment of corresponding handover parameters according to part or all of the information in the first report received. Optionally, the source network device can further send part or all of the part or all of the information in the first report received to the candidate target network device or the re-establishment network device, and then the candidate target network device or the re-establishment network device can perform adjustment of corresponding handover parameters according to the information received. The candidate target network device can be one or more and is not limited.

[0136] Optionally, if the first network device is not the candidate target network device, the first network device can further send part or all of the information in the first report to the candidate target network device after receiving the first report. Further, the candidate target network device can perform adjustment of corresponding handover parameters according to part or all of the information in the first report received. Optionally, the candidate target network device can further send part or all of the part or all of the information in the first report received to the source network device or the re-establishment network device, and then the source network device or the re-establishment network device can perform adjustment of corresponding handover parameters according to the information received.

[0137] Please refer to Figure 7 Another flowchart of a communication method provided by the embodiment of the present application is shown in FIG. 7. The method comprises the following steps.

[0138] In step S701, the terminal device receives N CHO configuration information from the source network device, each CHO configuration information indicating a CHO execution condition of a candidate cell corresponding to the CHO configuration information, the CHO execution condition being a CHO execution condition based on location information and / or time information and / or signal quality information, and N being an integer greater than 1.

[0139] For the specific implementation of step S701, please refer to the related description of step S501 in the foregoing description, which will not be repeated. It should be noted that in this embodiment, the CHO execution condition specifically refers to a CHO execution condition based on location information and / or time information and / or signal quality information.

[0140] In step S702, the terminal device performs handover to a second candidate cell corresponding to a second CHO configuration information when the CHO execution condition indicated by the second CHO configuration information meets.

[0141] In step S703, if access or handover failure (HOF) occurs in the second candidate cell, the terminal device determines a first cell to access according to the N CHO configuration information, the current location of the terminal device, and / or the current time, and / or the current signal quality.

[0142] In the embodiments of the present application, the CHO execution condition is satisfied, which can also be understood as the CHO execution condition being triggered. Thus, in step S702, if the CHO execution condition indicated by the second CHO configuration information is triggered, it means that the terminal device determines the second candidate cell as the target cell and performs a corresponding handover process to attempt to access the second candidate cell.

[0143] In view of this, the access or handover failure of the terminal device in the second candidate cell in step S503 can mean that, after the terminal device determines the target cell from the N CHO configuration information corresponding to the candidate cells, the access or handover failure occurs in the target cell, or the terminal device fails to successfully access or handover to the determined target cell.

[0144] In this embodiment, the current location of the terminal device can be the location of the terminal device when the access or handover failure occurs in the second candidate cell. The current location of the terminal device can be a geographic location, such as latitude and longitude values, or a relative location, such as the distance between the terminal device and a satellite, and is not limited. Correspondingly, the current time can be the time when the access or handover failure occurs in the second candidate cell. The current signal quality can be the signal quality of one or more of the candidate cells, the source cell, and other cells when the access or handover failure occurs in the second candidate cell.

[0145] Specifically, if the current location of the terminal device, and / or the current time, and / or the current signal quality matches one of the N CHO configuration information, the terminal device can determine the first cell as the first candidate cell corresponding to the matched first CHO configuration information, and then the terminal device can access the first cell according to the first CHO configuration information.

[0146] If the current location and / or the current time and / or the current signal quality of the terminal device matches multiple CHO configuration information in the N CHO configuration information, the terminal device can select one candidate cell as the first cell from the candidate cells corresponding to the multiple CHO configuration information, and then access the first cell according to the corresponding CHO configuration information. It should be noted that in this case, which candidate cell the terminal device selects as the first cell, or which candidate cell the terminal device selects to access, can be based on the terminal device implementation, and the present application does not limit it. For example, the terminal device can determine the first CHO configuration information from the multiple CHO configuration information according to the signal quality of the candidate cells corresponding to the multiple CHO configuration information respectively, and the first candidate cell corresponding to the first CHO configuration information can be the candidate cell with the best signal quality among the candidate cells corresponding to the N CHO configuration information. The signal quality can be one or more of RSRP, RSRQ, SINR, or can include other parameters, and is not limited.

[0147] Optionally, the first CHO configuration information can include related information of the first candidate cell, and the terminal device can use the related information of the first candidate cell to access the first candidate cell. The specific content of the related information of the candidate cell can refer to the description in the above, and will not be repeated here.

[0148] If the current location and / or the current time and / or the current signal quality of the terminal device does not match the N CHO configuration information, but the current location of the terminal device is within the cell range of the source cell, the terminal device can determine the first cell as the source cell, and then perform re-establishment in the source cell, that is, in this case, the terminal device can fall back to the source cell.

[0149] If the current location and / or the current time and / or the current signal quality of the terminal device does not match the N CHO configuration information, and the current location of the terminal device is also not within the cell range of the source cell, the terminal device can determine that the first cell is neither a candidate cell nor a source cell. The terminal device can determine the candidate cells corresponding to the N CHO configuration information and other cells other than the source cell as the first cell, and perform re-establishment in the first cell.

[0150] The meaning of the current location and / or the current time and / or the current signal quality of the terminal device matching the CHO configuration information, and the way to determine whether the current location and / or the current time and / or the current signal quality of the terminal device matches a certain CHO configuration information can refer to the related description in the above, which will not be repeated here.

[0151] According to the above, in this embodiment, when the terminal device meets the CHO execution condition indicated by the second CHO configuration information among the N CHO configuration information, access failure or handover failure occurs in the second candidate cell corresponding to the second CHO configuration information, or when the terminal device determines the target cell according to the N CHO configuration information, but access failure or handover failure occurs in the target cell, the terminal device can select the cell to be accessed according to the N CHO configuration information, the current location and / or current time and / or current signal quality of the terminal device. The cell to be accessed can also be understood as the cell to be connected, or the cell to be re-established, etc. If the current location and / or current time and / or current signal quality of the terminal device matches one or more CHO configuration information among the N CHO configuration information, the terminal device can select a candidate cell configured by the source network device to access. Specifically, the terminal device can select a first candidate cell corresponding to the first CHO configuration information among the one or more CHO configuration information matching the terminal device as a first cell, and access the first candidate cell according to the related information of the first candidate cell in the first CHO configuration information, such as the C-RNTI allocated to the terminal device by the first candidate cell, the RACH resource information required to access the first candidate cell, etc. The way of selecting the first CHO configuration information or the first candidate cell is not limited in the present application.

[0152] If the current location and / or current time and / or current signal quality of the terminal device does not match the N CHO configuration information, but the current location of the terminal device is within the cell range of the source cell, the terminal device can fall back to the source cell and perform re-establishment in the source cell. That is, in this case, the first cell is the source cell, and the terminal device can select to access the source cell.

[0153] If the current location and / or current time and / or current signal quality of the terminal device does not match the N CHO configuration information, and the current location of the terminal device is not within the cell range of the source cell, in this case, the first cell is neither a candidate cell nor a source cell, and the terminal device can determine other cells (i.e. non-candidate cells, non-source cells) as the first cell to be accessed, and perform re-establishment in the first cell.

[0154] Therefore, the technical solution provides a CHO failure processing mechanism when a terminal device fails to access or hand over a candidate cell after the CHO execution condition is met in a scenario where the CHO execution condition is based on location information and / or time information and / or signal quality information. The terminal device can determine a cell to access according to the location, time, signal quality and CHO configuration information when the access or handover failure occurs, so that the terminal device can perform reasonable processing after the access or handover failure, reduce the interruption delay caused by the access or handover failure, and improve the system performance.

[0155] In one specific example, the source network device can provide three CHO configuration information for the terminal device, which are CHO configuration information A, CHO configuration information B and CHO configuration information C respectively. Specifically, the CHO configuration information A includes time period information A and related information A, wherein the time period information A is used to indicate the CHO execution condition of the candidate cell A corresponding to the CHO configuration information A, for example, the time period information A can be {UTC time1, UTC time2}, indicating that when the time reaches {UTC time1, UTC time2}, the CHO execution condition of the candidate cell A is satisfied; the related information A is used to indicate the related information of the candidate cell A corresponding to the CHO configuration information A, such as the C-RNTI allocated by the candidate cell A to the terminal device, the RACH resource information required for accessing the candidate cell A, etc. The CHO configuration information B includes time period information B and related information B, wherein the time period information B is used to indicate the CHO execution condition of the candidate cell B corresponding to the CHO configuration information B, for example, the time period information B can be {UTC time3, UTC time4}, indicating that when the time reaches {UTC time3, UTC time4}, the CHO execution condition of the candidate cell B is satisfied; the related information B is used to indicate the related information of the candidate cell B corresponding to the CHO configuration information B. The CHO configuration information C includes time period information C and related information C, wherein the time period information C is used to indicate the CHO execution condition of the candidate cell C corresponding to the CHO configuration information C, for example, the time period information C can be {UTC time5, UTC time6}, indicating that when the time reaches {UTC time5, UTC time6}, the CHO execution condition of the candidate cell C is satisfied; the related information C is used to indicate the related information of the candidate cell C corresponding to the CHO configuration information C. In this way, after the terminal device receives the above-mentioned CHO configuration information A, CHO configuration information B and CHO configuration information C, when the time reaches {UTC time1, UTC time2}, the CHO execution condition of the candidate cell A is satisfied, and the terminal device can perform handover to the candidate cell A. If the terminal device fails to access or handover in the candidate cell A, further, if the terminal device is located in the cell range of the candidate cell B at this time, the terminal device can access the candidate cell B using the related information B. If the terminal device is not located in the cell range of the candidate cell A, nor in the cell range of the candidate cell B, nor in the cell range of the candidate cell C, but in the cell range of the source cell at this time, the terminal device can fall back to the source cell. If the terminal device is not located in the cell range of the candidate cell A, nor in the cell range of the candidate cell B, nor in the cell range of the candidate cell C, and nor in the cell range of the source cell at this time, the terminal device can perform re-establishment in other cells.

[0156] In another specific example, the source network device can provide three CHO configuration information for the terminal device, which are CHO configuration information E, CHO configuration information F and CHO configuration information G respectively. Specifically, the CHO configuration information E includes timer information E and related information E, wherein the timer information E is used to indicate the CHO execution condition of the candidate cell E corresponding to the CHO configuration information E, for example, the timer information E can be the valid time length of timer E (i.e. timer1), which indicates that when the valid time length of the timer E arrives, the timer E is triggered, the CHO execution condition of the candidate cell E is satisfied, and the terminal device can attempt to access the candidate cell E; the related information E is used to indicate the related information of the candidate cell E corresponding to the CHO configuration information E, such as the C-RNTI allocated by the candidate cell E for the terminal device, the RACH resource information required for accessing the candidate cell E, etc. The CHO configuration information F includes timer information F and related information F, wherein the timer information F is used to indicate the CHO execution condition of the candidate cell F corresponding to the CHO configuration information F, for example, the timer information F can be the valid time length of timer F (timer2), which indicates that when the valid time length of the timer F arrives, the timer F is triggered, the CHO execution condition of the candidate cell F is satisfied, and the terminal device can attempt to access the candidate cell F; the related information F is used to indicate the related information of the candidate cell F corresponding to the CHO configuration information F. The CHO configuration information G includes timer information G and related information G, wherein the timer information G is used to indicate the CHO execution condition of the candidate cell G corresponding to the CHO configuration information G, for example, the timer information G can be the valid time length of timer G (i.e. timer3), which indicates that when the valid time length of the timer G arrives, the timer G is triggered, the CHO execution condition of the candidate cell G is satisfied, and the terminal device can attempt to access the candidate cell G; the related information G is used to indicate the related information of the candidate cell G corresponding to the CHO configuration information G. In this way, after the terminal device receives the above-mentioned CHO configuration information E, CHO configuration information F and CHO configuration information G, the terminal device can start the timer E, timer F and timer G. When the valid time length of the timer E arrives, the CHO execution condition of the candidate cell E is satisfied, and the terminal device can perform handover to the candidate cell E. If the terminal device fails to access or handover in the candidate cell E, further, if the terminal device is located in the cell range of the candidate cell F at this time, the terminal device can access the candidate cell F using the related information F. If the terminal device is not located in the cell range of the candidate cell E, nor in the cell range of the candidate cell F, nor in the cell range of the candidate cell G, but in the cell range of the source cell at this time, the terminal device can fall back to the source cell. If the terminal device is not located in the cell range of the candidate cell E, nor in the cell range of the candidate cell F, nor in the cell range of the candidate cell G, and nor in the cell range of the source cell at this time, the terminal device can perform re-establishment in other cells.

[0157] Optionally, the terminal device can also record the relevant information of the connection failure after the access or handover failure occurs in the second candidate cell, generate a second report, and report the second report to the first network device. The second report can include one or more of the following information:

[0158] 1) failedPcellID: cell information of the access failure cell, or cell information of the cell in which the terminal device fails to access or handover, i.e., cell information of the second candidate cell.

[0159] 2) connectionFailureType: connection failure type, such as HOF or conditional handover failure (CHOF).

[0160] 3) previousPCellId: cell information of the source cell.

[0161] 4) cell information of the cell in which the terminal device resumes connection after the access failure, i.e., cell information of the first cell accessed by the terminal device after the access or handover failure occurs in the second candidate cell.

[0162] 5) C-RNTI allocated to the terminal device by the source cell, and / or C-RNTI allocated to the terminal device by the access failure cell (i.e., the second candidate cell).

[0163] 6) time period information from when the terminal device receives the CHO configuration information to when the handover is triggered, or time period information from when the terminal device receives the CHO configuration information to when the terminal device performs handover with the second candidate cell. Optionally, when the CHO execution condition information is timer information, the information can be timer information of the second candidate cell, i.e., the effective duration of the timer corresponding to the second candidate cell.

[0164] 7) time period information from when the handover is triggered to when the access failure occurs.

[0165] 8) time period information from when the access failure occurs to when the connection is resumed.

[0166] 9) time period information from when the connection is resumed to when the second report is reported, and / or time period information from when the access failure occurs to when the second report is reported.

[0167] 10) time information at the time of the access failure, such as an absolute time value (e.g., UTC time) at the time of the access failure.

[0168] 11) location information of the terminal device at the time of the access failure. For example, it can be an absolute location of the terminal device (e.g., latitude and longitude values), or a relative location of the terminal device (e.g., distance between the terminal device and a satellite).

[0169] 12), the signal quality of the source cell and / or each candidate cell (including the candidate cell of access failure and other candidate cells). For example, the signal quality of the source cell and / or each candidate cell at one or more of the following time nodes can be included: when the terminal device receives the CHO configuration information, when the access fails, when the connection is recovered, when the terminal device reports the second report, etc.

[0170] It should be noted that the first network device can be a network device to which the source cell belongs (i.e., a source network device), a network device to which the connection failure cell belongs (i.e., a candidate target network device), a network device to which the connection recovery cell or the re-establishment cell or the successfully accessed cell belongs (i.e., a network device to which the first cell belongs), or other network devices, and is not limited.

[0171] Specifically, the process of the terminal device reporting the second report to the first network device and the process of the first network device after receiving the second report can refer to the related description of the first report above, and will not be repeated here.

[0172] Optionally, if the terminal device successfully accesses the second candidate cell, the terminal device can also record the related information of the successful access, generate a fourth report, and report the fourth report to the first network device. The fourth report can include one or more of the following information:

[0173] 1), successfulPcellID: cell information of the successfully accessed cell, or cell information of the cell to which the terminal device successfully accesses, i.e., cell information of the second candidate cell.

[0174] 2), connectionSuccessType: connection success type, such as CHO success.

[0175] 3), previousPCellId: cell information of the source cell.

[0176] 4), C-RNTI allocated by the source cell to the terminal device, and / or C-RNTI allocated by the successfully accessed cell (i.e., the second candidate cell) to the terminal device.

[0177] 5), time information at the time of successful access, such as absolute time value (e.g., UTC time) at the time of successful access, or relative time value (e.g., time period information from receiving the CHO configuration information to successful access).

[0178] 6), time period information from successful access to reporting the fourth report.

[0179] 7) the location information of the terminal device when the access is successful. For example, it can be the absolute position of the terminal device (such as longitude and latitude values), or it can be the relative position of the terminal device (such as the distance between the terminal device and the satellite).

[0180] Similarly, in this scenario, the first network device can be the network device to which the source cell belongs (i.e., the source network device), or the network device to which the access-successful cell belongs (i.e., the target network device), or it can also be another network device, and is not limited.

[0181] Specifically, the process in which the terminal device reports the fourth report to the first network device can refer to the related description of the first report and the second report in the foregoing, and will not be described again.

[0182] Optionally, if the first network device is not the source network device, after receiving the fourth report, the first network device can also send part or all of the information in the fourth report to the source network device. Further, after receiving part or all of the information in the fourth report, the source network device can adjust the corresponding handover parameters according to part or all of the received information in the fourth report. Optionally, the source network device can also send part or all of the received part or all of the information in the fourth report to the target network device, and then the target network device can adjust the corresponding handover parameters according to the received information after receiving the information.

[0183] Optionally, if the first network device is not the target network device, after receiving the fourth report, the first network device can also send part or all of the information in the fourth report to the target network device. Further, after receiving part or all of the information in the fourth report, the target network device can adjust the corresponding handover parameters according to part or all of the received information in the fourth report. Optionally, the target network device can also send part or all of the received part or all of the information in the fourth report to the source network device, and then the source network device can adjust the corresponding handover parameters according to the received information after receiving the information.

[0184] Please refer to Figure 8 Another flowchart of a communication method provided by the embodiment of the present application is shown in FIG. 8. The method comprises the following steps.

[0185] In step S801, the terminal device receives N CHO configuration information from the source network device, wherein each CHO configuration information indicates the CHO execution condition of the candidate cell corresponding to the CHO configuration information, and the CHO execution condition is a CHO execution condition based on location information and / or time information and / or signal quality, and N is an integer greater than 1.

[0186] For the implementation of step S801, refer to the description of step S501 and step S701 above. It should be noted that in this embodiment, the CHO execution condition specifically refers to a CHO execution condition based on location information and / or time information and / or signal quality information.

[0187] Step S802, before the CHO execution condition indicated in any of the N CHO configuration information is met, the terminal device receives a first message from the source network device, and the first message indicates the terminal device to perform a legacy handover.

[0188] In this embodiment, the source network device can maintain the RRC connection or data transmission with the terminal device until the terminal device determines a target cell from the N CHO configuration information, or until the terminal device successfully accesses / handovers to the target cell, where the target cell refers to a candidate cell that meets the corresponding CHO execution condition. In this way, after the source network device sends the RRC message including the N CHO configuration information to the terminal device, it can subsequently send another RRC message, i.e. the first message in step S802, to the terminal device, which is used to instruct the terminal device to perform a legacy handover. The first message can be a legacy handover message, a handover command message, an RRC reconfiguration message, or have other names, which are not limited. The first message can also indicate the target cell to which the terminal device is to handover. Subsequently, after receiving the first message, the terminal device can stop the CHO process, for example, stop the process of attempting to determine the target cell from the configured candidate cells, and perform a legacy handover to the target cell indicated in the first message according to the first message. The legacy handover can also be referred to as handover, ordinary handover, general handover, etc., or have other names, which are not limited.

[0189] Step S803, if the performed legacy handover fails, the terminal device determines a first cell to access according to the N CHO configuration information, the current location and / or current time and / or current signal quality of the terminal device.

[0190] In this embodiment, the current location of the terminal device can refer to the location of the terminal device when the conventional handover performed by the terminal device fails, or when the terminal device fails to access or hand over to the target cell of the conventional handover, and can be a geographical location such as longitude and latitude values, or a relative location such as the distance between the terminal device and a satellite, and is not limited. Correspondingly, the current time can refer to the time when the conventional handover performed by the terminal device fails, or when the terminal device fails to access or hand over to the target cell of the conventional handover. The current signal quality can refer to the signal quality of one or more of the candidate cells, the source cell and other cells when the conventional handover performed by the terminal device fails, or when the terminal device fails to access or hand over to the target cell of the conventional handover.

[0191] Specifically, if the current location of the terminal device and / or the current time and / or the current signal quality match one of the N CHO configuration information, the terminal device can determine that the first cell is the first candidate cell corresponding to the matched first CHO configuration information, and then the terminal device can access the first cell according to the first CHO configuration information.

[0192] If the current location of the terminal device and / or the current time and / or the current signal quality match multiple CHO configuration information of the N CHO configuration information, the terminal device can select one of the candidate cells corresponding to the matched multiple CHO configuration information as the first cell, and then access the first cell according to the corresponding CHO configuration information. It should be noted that in this case, which candidate cell the terminal device selects as the first cell, or which candidate cell the terminal device selects to access, can be based on the implementation of the terminal device, and the present application does not limit it. For example, the terminal device can determine the first CHO configuration information from the multiple CHO configuration information according to the signal quality of the candidate cells corresponding to the multiple CHO configuration information respectively, and determine the first candidate cell corresponding to the first CHO configuration information as the first cell, and then access the first cell according to the first CHO configuration information. Optionally, the first candidate cell corresponding to the first CHO configuration information can be one of the candidate cells corresponding to the N CHO configuration information with the best signal quality, and the signal quality can be one or more of RSRP, RSRQ, SINR, or can include other parameters, and is not limited.

[0193] Optionally, the first CHO configuration information can include related information of the first candidate cell, and the terminal device can use the related information of the first candidate cell to access the first candidate cell. The specific content of the related information of the candidate cell can be referred to the description in the above, and will not be repeated here.

[0194] If the current location of the terminal device and / or the current time and / or the current signal quality do not match the N CHO configuration information, but the current location of the terminal device is within the cell range of the source cell, the terminal device can determine that the first cell is the source cell, and then perform re-establishment in the source cell, that is, in this case, the terminal device can fall back to the source cell.

[0195] If the current location of the terminal device and / or the current time and / or the current signal quality do not match the N CHO configuration information, and the current location of the terminal device is also not within the cell range of the source cell, the terminal device can determine that the first cell is neither a candidate cell nor a source cell. The terminal device can determine other cells in addition to the candidate cells corresponding to the N CHO configuration information and the source cell as the first cell, and perform re-establishment in the first cell.

[0196] The meaning of the current location of the terminal device and / or the current time and / or the current signal quality matching the CHO configuration information, and the manner of determining whether the current location of the terminal device and / or the current time and / or the current signal quality matches a certain CHO configuration information can refer to the related description in the foregoing, which will not be repeated here.

[0197] According to the foregoing, in this embodiment, when the terminal device receives a first message indicating traditional switching from the source network device before the CHO execution condition indicated by the N CHO configuration information is met, but the traditional switching performed fails, or in other words, access or switching to the target cell indicated in the first message fails, the terminal device can select a cell to access according to the N CHO configuration information, the current location of the terminal device and / or the current time and / or the current signal quality. The cell to access can also be understood as a cell to resume connection, or a cell to re-establish, etc. If the current location of the terminal device and / or the current time and / or the current signal quality matches one or more CHO configuration information in the N CHO configuration information, the terminal device can select a certain candidate cell configured by the source network device to access. Specifically, the terminal device can select a first candidate cell corresponding to a first CHO configuration information in the one or more CHO configuration information matching the terminal device as a first cell, and access the first candidate cell according to the related information of the first candidate cell in the first CHO configuration information, such as the C-RNTI allocated to the terminal device by the first candidate cell, the RACH resource information required to access the first candidate cell, etc. The manner of selecting the first CHO configuration information or the first candidate cell is not specifically limited in the present application.

[0198] If the current location of the terminal device and / or the current time and / or the current signal quality do not match the N CHO configuration information, but the current location of the terminal device is within the cell range of the source cell, the terminal device can fall back to the source cell and perform re-establishment in the source cell. That is, in this case, the first cell is the source cell, and the terminal device can select to access the source cell.

[0199] If the current location of the terminal device and / or the current time and / or the current signal quality do not match the N CHO configuration information, and the current location of the terminal device is also not within the cell range of the source cell, in this case, the first cell is neither a candidate cell nor a source cell, and the terminal device can determine other cells (i.e., non-candidate cells, non-source cells) as the first cell to be accessed and perform re-establishment in the first cell.

[0200] Therefore, the above technical solution provides a CHO failure processing mechanism when the terminal device receives a first message from the source network device indicating to perform traditional switching before the CHO execution condition is met, but the traditional switching fails. The terminal device can determine the cell to be accessed according to the location, time, signal quality when the traditional switching fails, and the CHO configuration information, so that the terminal device can perform reasonable processing after the traditional switching fails, reduce the interruption delay caused by the switching failure, and improve the system performance.

[0201] In one specific example, the source network device can provide three CHO configuration information for the terminal device, which are CHO configuration information E, CHO configuration information F and CHO configuration information G respectively. Specifically, the CHO configuration information E includes timer information E and related information E, wherein the timer information E is used to indicate the CHO execution condition of the candidate cell E corresponding to the CHO configuration information E, for example, the timer information E can be the valid time length of timer E (i.e. timer1), which indicates that when the valid time length of the timer E arrives, the timer E is triggered, the CHO execution condition of the candidate cell E is met, and the terminal device can attempt to access the candidate cell E; the related information E is used to indicate the related information of the candidate cell E corresponding to the CHO configuration information E, such as the C-RNTI allocated by the candidate cell E for the terminal device, the RACH resource information required for accessing the candidate cell E, etc. The CHO configuration information F includes timer information F and related information F, wherein the timer information F is used to indicate the CHO execution condition of the candidate cell F corresponding to the CHO configuration information F, for example, the timer information F can be the valid time length of timer F (timer2), which indicates that when the valid time length of the timer F arrives, the timer F is triggered, the CHO execution condition of the candidate cell F is met, and the terminal device can attempt to access the candidate cell F; the related information F is used to indicate the related information of the candidate cell F corresponding to the CHO configuration information F. The CHO configuration information G includes timer information G and related information G, wherein the timer information G is used to indicate the CHO execution condition of the candidate cell G corresponding to the CHO configuration information G, for example, the timer information G can be the valid time length of timer G (i.e. timer3), which indicates that when the valid time length of the timer G arrives, the timer G is triggered, the CHO execution condition of the candidate cell G is met, and the terminal device can attempt to access the candidate cell G; the related information G is used to indicate the related information of the candidate cell G corresponding to the CHO configuration information G. In this way, after receiving the above-mentioned CHO configuration information E, CHO configuration information F and CHO configuration information G, the terminal device can start the timer E, timer F and timer G. When the valid time lengths of the timer E, timer F and timer G have not arrived, if the terminal device receives a traditional handover message from the source network device indicating that the terminal device is handed over to another cell H, the terminal device can stop the CHO process and perform traditional handover to the cell H. If the traditional handover performed by the terminal device to the cell H fails, further if the terminal device is located in the cell range of the candidate cell F at this time, the terminal device can access the candidate cell F using the related information F. If the terminal device is not located in the cell range of the candidate cell E, not in the cell range of the candidate cell F, and not in the cell range of the candidate cell G, but in the cell range of the source cell at this time, the terminal device can fall back to the source cell.If the terminal device is not in the cell range of the candidate cell E, not in the cell range of the candidate cell F, not in the cell range of the candidate cell G, and not in the cell range of the source cell, the terminal device can perform re-establishment in other cells.

[0202] Optionally, the terminal device can also record the information related to the failure of the conventional handover, generate a third report, and report the third report to the first network device. The third report can include one or more of the following information:

[0203] 1) failedPcellID: cell information of the access failure cell, or cell information of the cell in which the terminal device fails to access or handover, i.e., cell information of the target cell of the conventional handover.

[0204] 2) connectionFailureType: connection failure type, such as HOF.

[0205] 3) previousPCellId: cell information of the source cell.

[0206] 4) cell information of the first cell in which the terminal device resumes connection after the access failure, i.e., cell information of the first cell in which the terminal device accesses after the failure of the conventional handover performed to the target cell.

[0207] 5) C-RNTI allocated to the terminal device by the source cell, and / or C-RNTI allocated to the terminal device by the access failure cell, i.e., the target cell of the conventional handover.

[0208] 6) timer information and / or signal quality threshold. Optionally, the CHO execution condition information can include timer information and / or channel quality information. When the CHO execution condition information includes timer information, the timer information specifically refers to one or more of the timer information of each candidate cell included in the N CHO configuration information, i.e., the valid time length of the timer corresponding to each candidate cell. When the CHO execution condition information includes signal quality information, the signal quality threshold specifically refers to the threshold corresponding to the CHO execution event of each candidate cell included in the N CHO configuration information.

[0209] 7) time period information from receiving the CHO configuration information to receiving the first message (i.e., the conventional handover message).

[0210] 8) time period information from receiving the first message (i.e., the conventional handover message) to the failure of the conventional handover.

[0211] 9) time period information from the failure of the conventional handover to the connection recovery.

[0212] 9) time period information from connection resuming to reporting the third report, and / or time period information from traditional handover failure to reporting the third report.

[0213] 10) time information at the time of access failure, such as an absolute time value (e.g. UTC time) at the time of traditional handover failure.

[0214] 11) position information of the terminal device at the time of access failure, which can be an absolute position (e.g. longitude and latitude values) of the terminal device at the time of traditional handover failure, or a relative position (e.g. distance between the terminal device and a satellite).

[0215] 12) signal quality of the source cell and / or the access failure cell (i.e. target cell of traditional handover) and / or each candidate cell, which can be the signal quality of the source cell and / or the access failure cell and / or each candidate cell when the terminal device receives the CHO configuration information, and / or when the terminal device receives the first message, and / or when the terminal device performs traditional handover, and / or when the performed traditional handover fails, and / or when the connection resumes, and / or when the third report is reported.

[0216] It should be noted that the first network device can be a network device to which the source cell belongs (i.e. source network device), a network device to which the connection failure cell belongs (i.e. target network device of traditional handover), a network device to which the cell for resuming connection or the reestablishment cell or the successfully accessed cell belongs (i.e. network device to which the first cell belongs), or other network devices, and is not limited.

[0217] Specifically, the process of the terminal device reporting the third report to the first network device can refer to the related description of the first report and the second report in the foregoing, and will not be described herein again.

[0218] Optionally, if the first network device is not the source network device, the first network device can further send part or all of the information in the third report to the source network device after receiving the third report. Further, the source network device can adjust the corresponding handover parameters according to part or all of the information in the third report received by the source network device. Optionally, the source network device can further send part or all of the part or all of the information in the third report received by the source network device to the target network device of traditional handover or the reestablishment network device, and then the target network device or the reestablishment network device can adjust the corresponding handover parameters according to the received information.

[0219] Optionally, if the first network device is not the target network device of the legacy handover, the first network device can further send part or all of the information in the first report to the target network device after receiving the first report. Further, the target network device can adjust the corresponding handover parameters according to part or all of the information in the first report after receiving part or all of the information in the first report. Optionally, the target network device can further send part or all of the part or all of the information in the first report to the source network device or the re-establishment network device, and then the source network device or the re-establishment network device can adjust the corresponding handover parameters according to the received information after receiving the information.

[0220] Optionally, if the legacy handover performed by the terminal device is successful, i.e., the terminal device successfully accesses the target cell of the legacy handover, the terminal device can further record the information related to the successful handover, generate a fifth report, and report the fifth report to the first network device. The fifth report can include one or more of the following information:

[0221] 1) successfulPcellID: cell information of the successfully accessed cell, or cell information of the cell successfully accessed by the terminal device, i.e., cell information of the target cell of the legacy handover.

[0222] 2) connectionSuccessType: connection success type, such as HO success.

[0223] 3) previousPCellId: cell information of the source cell.

[0224] 4) C-RNTI allocated to the terminal device by the source cell, and / or C-RNTI allocated to the terminal device by the successfully accessed cell (i.e., the target cell of the legacy handover).

[0225] 5) time information at the time of successful access, such as absolute time value (e.g., UTC time) at the time of successful access, or relative time value (e.g., time period information from receiving the first message to successful access).

[0226] 6) time period information from receiving the CHO configuration information to receiving the first message.

[0227] 7) time period information from successful access to reporting the fifth report.

[0228] 8) location information of the terminal device at the time of successful access. For example, it can be absolute location (e.g., latitude and longitude values) of the terminal device, or relative location (e.g., distance between the terminal device and a satellite).

[0229] Similarly, in this scenario, the first network device can be a network device to which the source cell belongs (i.e., a source network device), can be a network device to which the access successful cell belongs (i.e., a target network device of traditional handover), or can be another network device, and is not limited.

[0230] Specifically, the process in which the terminal device reports the fifth report to the first network device can refer to the related descriptions of the first report, the second report, the third report, and the fourth report in the foregoing, and will not be described herein again.

[0231] Optionally, if the first network device is not the source network device, the first network device can further send part or all of the information in the fifth report to the source network device after receiving the fifth report. Further, the source network device can perform adjustment of corresponding handover parameters according to part or all of the information in the fifth report received. Optionally, the source network device can further send part or all of the part or all of the information in the fifth report received to the target network device, and then the target network device can perform adjustment of corresponding handover parameters according to the information received.

[0232] Optionally, if the first network device is not the target network device, the first network device can further send part or all of the information in the fifth report to the target network device after receiving the fifth report. Further, the target network device can perform adjustment of corresponding handover parameters according to part or all of the information in the fifth report received. Optionally, the target network device can further send part or all of the part or all of the information in the first report received to the source network device, and then the source network device can perform adjustment of corresponding handover parameters according to the information received.

[0233] The communication method provided by the embodiments of the present application is respectively applicable to three different handover failure scenarios. The three handover failure scenarios are: wireless link failure with the source cell before the CHO execution condition is met, access or handover failure with the candidate cell after the CHO execution condition is met, and receiving a traditional handover message before the CHO execution condition is met but failure of the executed traditional handover.

[0234] For the above various handover failure scenarios, after the first network device receives the information reported by the terminal device (for the sake of description, it is assumed that the terminal device sends the RLF report to the first network device), it can forward part or all of the information received from the terminal device to the source network device or the target network device or the network device to which the candidate cell belongs. When there is a direct connection communication interface (such as X2 / Xn interface) between the first network device and the source network device or the target network device or the network device to which the candidate cell belongs, the information can be forwarded through the X2 / Xn interface. When there is no direct connection communication interface between the first network device and the source network device or the target network device or the network device to which the candidate cell belongs, the information can be forwarded through the core network device (such as AMF). That is, the first network device can send the RLF report or part or all of the information contained in the RLF report to the core network device through the communication interface between the core network device.

[0235] Specifically, the first network device sends the RLF report or part or all of the information contained in the RLF report to the core network device through the S1 or NG interface, and the core network device forwards the information received from the first network device to the source network device or the target network device or the network device to which the candidate cell belongs. An example, the first network device can send the RLF report or part or all of the information contained in the RLF report to the source network device or the target network device or the network device to which the candidate cell belongs through at least one of the following messages on the S1 / NG interface: uplink RAN configuration transmission (UPLINK RAN CONFIGURATION TRANSFER) message, downlink RAN configuration transmission (DOWNLINK RAN CONFIGURATION TRANSFER) message, base station configuration transmission (eNB CONFIGURATION TRANSFER or gNB CONFIGURATION TRANSFER) message, core network device configuration transmission (MME CONFIGURATION TRANSFER or AMF CONFIGURATION TRANSFER) message or other messages.

[0236] In addition, in the embodiments of the present application, when the source network device and the target network device, or the source network device and the network device to which the candidate cell belongs, or the target network device and the network device to which the candidate cell belongs, cannot directly communicate through the X2 / Xn interface, information can also be transmitted through the core network device. For example, the target network device can send, through an interface (such as an S1 or NG interface) between the target network device and the core network device, part or all of the information received by the target network device from the first network device to the core network device, and then the core network device forwards part or all of the information received from the target network device to the source network device through the S1 or NG interface.

[0237] If the terminal device / first network device / source network device / target network device / network device to which the candidate cell belongs is in a split form including a CU node and a DU node, the CU node as the receiver of the message / information can send part or all of the received information to the DU node. Optionally, if the CU node can be further divided into a control plane (CU-CP) and a user plane (CU-UP), the CU-CP node as the receiver of the message / information can send part or all of the received information to the CU-UP node. The CU node, the DU node, the CU-CP node, and the CU-UP node can correspond to the terminal device, the first network device, the source network device, the target network device, or the network device to which the candidate cell belongs.

[0238] It should be noted that the transmission process between the nodes described above can be applied to any CHO failure scenario in the embodiments of the present application. For example, taking the terminal device sending an RLF report to the first network device as an example, if the first network device is in a split form including a CU node and a DU node, the CU node of the first network device can receive the RLF report from the terminal device. Optionally, the CU node can also send part or all of the information included in the received RLF report to the DU node. Optionally, if the CU node can be divided into a control plane (CU-CP) and a user plane (CU-UP), the CU-CP node can further send part or all of the information included in the received RLF report to the CU-UP node.

[0239] The embodiments of the present application also provide a communication device, which refers to Figure 9 A structural schematic diagram of a communication device provided in the embodiments of the present application is shown in FIG. 9. The communication device 900 includes a transceiver module 910 and a processing module 920.

[0240] In an embodiment, the communication apparatus can be configured to implement the functions of a terminal device involved in any of the above method embodiments. For example, the communication apparatus can be a terminal device, such as a handheld terminal device or a vehicle-mounted terminal device; the communication apparatus can also be a chip or circuit included in a terminal device, or an apparatus including a terminal device, such as a vehicle of various types, etc.

[0241] For example, when the communication apparatus performs the operations or steps of a terminal device in any of the method embodiments shown in the above embodiments, the transceiver 910 is configured to receive N conditional handover (CHO) configuration information from a source network device, each CHO configuration information indicating a CHO execution condition of a candidate cell corresponding to the CHO configuration information, the CHO execution condition being a CHO execution condition based on location information and / or time information and / or signal quality information, N being an integer greater than 1; the processing module 920 is configured to determine a first cell to access before a radio link failure occurs in a source cell, if the CHO execution condition indicated by any of the N CHO configuration information is met; and the processing module 920 is further configured to determine the first cell to access according to the N CHO configuration information, a current location and / or a current time and / or a current signal quality of the terminal device. Figure 5

[0242] In a possible design, the processing module 920 is specifically configured to, if the current location and / or the current time and / or the current signal quality of the terminal device matches a first CHO configuration information of the N CHO configuration information, determine that the first cell is a first candidate cell corresponding to the first CHO configuration information, and then access the first cell according to the first CHO configuration information.

[0243] In a possible design, the processing module 920 is specifically configured to, if the current location and / or the current time and / or the current signal quality of the terminal device does not match any of the N CHO configuration information, determine that the first cell is not a candidate cell, and then perform a re-establishment in the first cell.

[0244] ​In a possible design, the processing module 920 is further configured to generate a first report after a radio link failure occurs in the source cell, and the transceiver 910 is configured to report the first report to the first network device; where the first report includes one or more of the following information: cell information of the cell where the access failure occurs, a connection failure type, cell information of the source cell, cell information of a cell where the connection is recovered after the radio link failure, a C-RNTI allocated by the source cell to the terminal device, time information when the radio link failure occurs, time period information from the radio link failure to the connection recovery, time period information from the radio link failure to reporting the first report, time period information from the connection recovery to reporting the first report, location information of the terminal device when the radio link failure occurs, and signal quality of the source cell and / or each candidate cell.

[0245] When the communication apparatus performs operations or steps corresponding to the terminal device in the method embodiments shown in Figure 7 The transceiver 910 is configured to receive N conditional handover (CHO) configuration information from the source network device, where each CHO configuration information indicates a CHO execution condition of a candidate cell corresponding to the CHO configuration information, the CHO execution condition is a CHO execution condition based on location information and / or time information and / or signal quality, and N is an integer greater than 1; the processing module 920 is configured to perform handover to a second candidate cell corresponding to a second CHO configuration information in the N CHO configuration information when the CHO execution condition indicated by the second CHO configuration information is met; and the processing module 920 is further configured to determine a first cell to be accessed according to the N CHO configuration information, current location and / or current time and / or current signal quality of the terminal device if access or handover failure occurs in the second candidate cell.

[0246] In a possible design, the processing module 920 is specifically configured to determine the first cell as a first candidate cell corresponding to a first CHO configuration information in the N CHO configuration information if the current location and / or current time and / or current signal quality of the terminal device matches the first CHO configuration information, and then access the first cell, i.e., the first candidate cell, according to the first CHO configuration information.

[0247] In a possible design, the processing module 920 is specifically configured to determine the first cell as the source cell if the current location and / or current time and / or current signal quality of the terminal device does not match any of the N CHO configuration information and the current location of the terminal device is within the cell range of the source cell, and then perform re-establishment in the source cell.

[0248] In a possible design, the processing module 920 is specifically configured to: if the current location of the terminal device and / or the current time and / or the current signal quality do not match any of the N CHO configuration information, and the current location of the terminal device is not within the cell range of the source cell, determine that the first cell is neither a candidate cell nor the source cell, and then perform re-establishment at the determined first cell.

[0249] In a possible design, the processing module 920 is further configured to: if the terminal device fails in access or handover at the second candidate cell, generate a second report; and the transceiver 910 is further configured to: report the second report to the first network device, where the second report includes one or more of the following information: cell information of the cell where the access fails, time period information from when the second CHO configuration information is received to when the handover is triggered, time period information from when the handover is triggered to when the access fails, time period information from when the access fails to when the connection is recovered, time period information from when the connection is recovered to when the second report is reported, time period information from when the access fails to when the second report is reported, time information when the access fails, location information of the terminal device when the access fails, and signal quality of the source cell and / or each candidate cell.

[0250] When the communication apparatus performs the operations or steps of the method embodiments shown in Figure 8 In a possible design, the transceiver 910 is configured to: receive N conditional handover (CHO) configuration information from a source network device, where each CHO configuration information indicates a CHO execution condition of a candidate cell corresponding to the CHO configuration information, the CHO execution condition is a CHO execution condition based on location information and / or time information and / or signal quality, and N is an integer greater than 1; and the transceiver 910 is configured to: before the CHO execution condition indicated by any of the N CHO configuration information is met, receive a first message from the source network device, where the first message indicates to perform a traditional handover; and the processing module 920 is configured to: if the performed traditional handover fails, determine a first cell to be accessed according to the N CHO configuration information, a current location of the terminal device, and / or a current time and / or a current signal quality.

[0251] In a possible design, the processing module 920 is further configured to: if the current location of the terminal device and / or the current time and / or the current signal quality match one of the N CHO configuration information, determine that the first cell is a first candidate cell corresponding to the first CHO configuration information; and then access the first cell, i.e., the first candidate cell, according to the first CHO configuration information.

[0252] In a possible design, the processing module 920 is further configured to: if the current location of the terminal device and / or the current time and / or the current signal quality do not match the N CHO configuration information, and the current location of the terminal device is within the cell range of the source cell, determining that the first cell is the source cell, and then performing re-establishment in the source cell.

[0253] In a possible design, the processing module 920 is further configured to: if the current location of the terminal device and / or the current time and / or the current signal quality do not match the N CHO configuration information, and the current location of the terminal device is not within the cell range of the source cell, determining that the first cell is neither a candidate cell nor the source cell, and then performing re-establishment in the determined first cell.

[0254] In a possible design, the processing module 920 is further configured to: if the conventional handover performed by the terminal device fails, generating a third report, and the transceiver module 910 is further configured to: reporting the third report to the first network device, where the third report includes one or more of the following information: time period information from receiving the CHO configuration information to receiving the first message, time period information from receiving the first message to the conventional handover failure, time period information from the conventional handover failure to connection recovery, time period information from the connection recovery to reporting the third report, time period information from the conventional handover failure to reporting the third report, time information at the conventional handover failure, location information of the terminal device at the conventional handover failure, and signal quality of the source cell and / or each candidate cell.

[0255] The processing module 920 involved in the communication apparatus can be implemented by at least one processor or processor-related circuit component, and the transceiver module 910 can be implemented by at least one transceiver or transceiver-related circuit component or a communication interface. The operations and / or functions of each module in the communication apparatus are respectively used to implement the corresponding procedures of the methods shown in Figure 5 、 Figure 6 、 Figure 7 or Figure 8 , for brevity, details are not repeated here. Optionally, the communication apparatus can further include a storage module, which can be used to store data and / or instructions, and the transceiver module 910 and / or the processing module 920 can read and access the data and / or instructions in the storage module, so that the communication apparatus implements the corresponding method. The storage module can be implemented by at least one memory, for example.

[0256] The above-mentioned storage module, processing module and transceiver module can exist separately, or all or part of the modules can be integrated, for example, the storage module and the processing module are integrated, or the processing module and the transceiver module are integrated, etc.

[0257] Please refer to Figure 10Fig. 6 shows another structural diagram of a communication apparatus provided in the embodiments of the present application. The communication apparatus can be used to implement the functions of the terminal device in the method embodiments, for example, can be a terminal device or an apparatus capable of supporting the terminal device to implement the corresponding functions in the method embodiments.

[0258] The communication apparatus can include a processor 1001, a communication interface 1002, and a memory 1003. The communication interface 1002 is configured to communicate with other devices through a transmission medium, and can be a transceiver or an interface circuit such as a transceiving circuit, a transceiving chip, etc. The memory 1003 is configured to store program instructions and / or data, and the processor 1001 is configured to execute the program instructions stored in the memory 1003, thereby implementing the methods in the method embodiments. Optionally, the memory 1003 and the processor 1001 are coupled, and the coupling is indirect coupling or communication connection between apparatuses, units or modules, which can be electrical, mechanical or other forms, and is used for information interaction between apparatuses, units or modules.

[0259] In one embodiment, the communication interface 1002 can be specifically configured to perform the actions of the transceiver module 910, and the processor 1001 can be specifically configured to perform the actions of the processing module 920, which will not be described herein again.

[0260] The specific connection medium between the communication interface 1002, the processor 1001 and the memory 1003 is not limited in the embodiments of the present application. In the embodiments of the present application, Figure 10 the memory 1003, the processor 1001 and the communication interface 1002 are connected through a bus 1004, and the bus is represented by a thick line in Figure 10 , and the connection mode between other components is only schematically illustrated and is not limited. The bus can be divided into an address bus, a data bus, a control bus, etc. For convenience of representation, Figure 10 only one thick line is used in to represent that there is only one bus or one type of bus.

[0261] Please refer to Figure 11 , which shows a simplified structural diagram of a communication apparatus, which can be specifically a terminal device, and is used to implement the functions of the terminal device in any of the method embodiments. For the convenience of understanding and illustration, in Figure 11 , the terminal device is taken as a mobile phone as an example. As Figure 11As shown, the terminal device includes a processor, and can further include a memory, and of course, can further include a radio frequency circuit, an antenna, and an input and output device, etc. The processor is mainly used for processing communication protocols and communication data, and controlling the terminal device, executing software programs, processing data of the software programs, etc. The memory is mainly used for storing software programs and data. The radio frequency circuit is mainly used for conversion between a baseband signal and a radio frequency signal, and processing of the radio frequency signal. The antenna is mainly used for receiving and transmitting a radio frequency signal in the form of an electromagnetic wave. The input and output device, such as a touch screen, a display screen, a keyboard, etc., is mainly used for receiving data input by a user and outputting data to the user. It should be noted that some types of terminal devices can not have an input and output device.

[0262] When data needs to be sent, the processor performs baseband processing on the data to be sent, and outputs a baseband signal to the radio frequency circuit. The radio frequency circuit performs radio frequency processing on the baseband signal, and transmits a radio frequency signal in the form of an electromagnetic wave through the antenna. When data is sent to the terminal device, the radio frequency circuit receives a radio frequency signal through the antenna, converts the radio frequency signal into a baseband signal, and outputs the baseband signal to the processor. The processor converts the baseband signal into data and processes the data. For the sake of illustration, Figure 11 In the embodiment of the present application, only one memory and one processor are shown. In actual terminal device products, there can be one or more processors and one or more memories. The memory can also be referred to as a storage medium or a storage device, etc. The memory can be independent of the processor, or can be integrated with the processor. The embodiments of the present application do not limit this.

[0263] In the embodiments of the present application, the antenna and the radio frequency circuit with transceiving functions can be regarded as a transceiving unit of the terminal device, and the processor with processing functions can be regarded as a processing unit of the terminal device. As shown in the figure, Figure 11 As shown, the terminal device includes a transceiving unit 1110 and a processing unit 1120. The transceiving unit can also be referred to as a transceiver, a transceiver, a transceiving device, etc. The processing unit can also be referred to as a processor, a processing board, a processing module, a processing device, etc. Optionally, the devices in the transceiving unit 1110 for implementing the receiving function can be regarded as a receiving unit, and the devices in the transceiving unit 1110 for implementing the sending function can be regarded as a sending unit, that is, the transceiving unit 1110 includes a receiving unit and a sending unit. The transceiving unit can also be referred to as a transceiver, a transceiver, or a transceiving circuit, etc. The receiving unit can also be referred to as a receiver, a receiver, or a receiving circuit, etc. The sending unit can also be referred to as a transmitter, a transmitter, or a transmitting circuit, etc. It should be understood that the transceiving unit 1110 is used to perform the sending operation and the receiving operation of the terminal device in the above method embodiments, and the processing unit 1120 is used to perform other operations of the terminal device in addition to the transceiving operation in the above method embodiments.

[0264] The chip system further includes a processor coupled with the memory, and the memory is configured to store programs or instructions, and the programs or instructions, when executed by the processor, cause the chip system to implement the method of the corresponding terminal device or the method of the corresponding network device (e.g., the source network device or the target network device) in any of the above method embodiments.

[0265] Optionally, the processor in the chip system can be one or more. The processor can be implemented by hardware or software. When implemented by hardware, the processor can be a logic circuit, an integrated circuit, or the like. When implemented by software, the processor can be a general-purpose processor, and the implementation is achieved by reading software codes stored in the memory.

[0266] Optionally, the memory in the chip system can also be one or more. The memory can be integrated with the processor or arranged separately from the processor, and the application does not make any specific limitation. For example, the memory can be a non-transient processor, such as a read-only memory (ROM), which can be integrated on the same chip as the processor or arranged on different chips respectively, and the application does not make any specific limitation on the type of the memory or the arrangement of the memory and the processor.

[0267] For example, the chip system can be a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a system on chip (SoC), a central processor unit (CPU), a network processor (NP), a digital signal processor (DSP), a micro controller unit (MCU), a programmable logic device (PLD), or other integrated chips.

[0268] It should be understood that each step in the above method embodiments can be completed by the integrated logic circuit of the hardware in the processor or the instructions in the form of software. The method steps disclosed in the embodiments of the application can be directly embodied as hardware processor execution or executed by the combination of hardware and software modules in the processor.

[0269] The embodiment of the present application further provides a computer readable storage medium, wherein computer readable instructions are stored in the computer readable storage medium, and when the computer readable instructions are read and executed by a computer, the computer is caused to execute the method in any of the method embodiments.

[0270] The embodiment of the present application further provides a computer program product, when the computer program product is read and executed by a computer, the computer is caused to execute the method in any of the method embodiments.

[0271] The embodiment of the present application further provides a communication system, which comprises a source network device and a terminal device. Optionally, the communication system can further comprise at least one candidate target network device. Optionally, the communication system can further comprise a first network device, which can be the source network device or a target network device or a network device to which a reestablishment cell (i.e. a cell to which a connection is recovered) belongs or another network device. Optionally, the communication system can further comprise a core network device.

[0272] It should be understood that the processor mentioned in the embodiment of the present application can be a CPU, and can also be other general-purpose processors, DSPs, ASICs, FPGAs or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0273] It should also be understood that the memory referred to in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically EPROM (EEPROM) or a flash memory. The volatile memory can be a random access memory (RAM) used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM) and direct rambus RAM (DR RAM).

[0274] It should be noted that when the processor is a general processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, the memory (storage module) is integrated in the processor.

[0275] It should be noted that the memory described herein is intended to include, but not limited to, these and any other suitable types of memory.

[0276] It should be understood that the various numerical numbers involved in the various embodiments of the present application are only for the convenience of differentiation, and the size of the serial numbers of the above processes or steps does not mean the order of execution, the execution order of the processes or steps should be determined by its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0277] Those skilled in the art can clearly understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0278] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

[0279] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the above-described device embodiments are only schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms.

[0280] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0281] In addition, each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically independently, or two or more units can be integrated into one unit.

[0282] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application essentially or the parts that contribute to the prior art or parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a ROM, a RAM, a magnetic disk or an optical disk, and various media that can store program codes.

[0283] In the various embodiments of the present application, the terms and / or descriptions of different embodiments are consistent and can be mutually referred to if there is no special description and logical conflict. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationship.

Claims

1. A communication method characterized by comprising: The method is applied to a satellite communication system, and the method comprises: receiving N conditional handover (CHO) configuration information from a source network device, each CHO configuration information indicating a CHO execution condition of a candidate cell corresponding to the CHO configuration information, the CHO execution condition being a CHO execution condition based on location information and / or time information, N being an integer greater than 1, and the candidate cell being a satellite cell; before the CHO execution condition indicated by any CHO configuration information in the N CHO configuration information is satisfied, a radio link failure occurs in a source cell; determining a first cell to be accessed according to the N CHO configuration information, a current location of a terminal device, and / or a current time.

2. The method of claim 1, wherein, The determining of the first cell to be accessed according to the N CHO configuration information, the current location of the terminal device, and / or the current time comprises: if the current location of the terminal device and / or the current time match the first CHO configuration information in the N CHO configuration information, determining that the first cell is a first candidate cell corresponding to the first CHO configuration information; the method further comprises accessing the first cell according to the first CHO configuration information.

3. The method of claim 1, wherein, if the current location of the terminal device and / or the current time do not match any CHO configuration information in the N CHO configuration information, determining that the first cell is not a candidate cell; the method further comprises performing a re-establishment in the first cell.

4. The method according to any one of claims 1 to 3, characterized in that, After the radio link failure occurs in the source cell, the method further comprises: generating a first report, the first report comprising one or more of the following information: cell information of a cell in which access fails, a connection failure type, cell information of the source cell, cell information of a cell in which connection is recovered after the radio link failure, a C-RNTI allocated to the terminal device by the source cell, time information when the radio link failure occurs, time period information from the radio link failure to the connection recovery, time period information from the radio link failure to the reporting of the first report, time period information from the connection recovery to the reporting of the first report, location information of the terminal device when the radio link failure occurs, and signal quality of the source cell and / or each candidate cell; reporting the first report to the first network device.

5. The method of claim 4, wherein, The time information when the radio link failure occurs is an absolute time value when the radio link failure occurs in the source cell.

6. The method of claim 4, wherein, The location information of the terminal device when the radio link failure occurs is a relative location of the terminal device.

7. A communication method characterized by comprising: The method is applied to a satellite communication system, and the method comprises: receiving N conditional handover (CHO) configuration information from a source network device, each CHO configuration information indicating a CHO execution condition of a candidate cell corresponding to the CHO configuration information, the CHO execution condition being a CHO execution condition based on location information and / or time information, N being an integer greater than 1, and the candidate cell being a satellite cell; after the CHO execution condition indicated by a second CHO configuration information in the N CHO configuration information is satisfied, performing handover to a second candidate cell corresponding to the second CHO configuration information; If an access or handover failure occurs in the second candidate cell, a first cell to be accessed is determined according to the N CHO configuration information, a current location of the terminal device, and / or a current time.

8. The method of claim 7, wherein, The determining the first cell to be accessed according to the N CHO configuration information, the current location of the terminal device, and / or the current time comprises: If the current location of the terminal device and / or the current time matches first CHO configuration information in the N CHO configuration information, the first cell is determined as a first candidate cell corresponding to the first CHO configuration information. The method further comprises: accessing the first cell according to the first CHO configuration information.

9. The method of claim 7, wherein, The determining the first cell to be accessed according to the N CHO configuration information, the current location of the terminal device, and / or the current time comprises: If the current location of the terminal device and / or the current time does not match the N CHO configuration information, and the current location of the terminal device is within a cell range of a source cell, the first cell is determined as the source cell. The method further comprises: performing re-establishment in the source cell.

10. The method according to any one of claims 7 to 9, characterized in that, The determining the first cell to be accessed according to the N CHO configuration information, the current location of the terminal device, and / or the current time comprises: If the current location of the terminal device and / or the current time does not match the N CHO configuration information, and the current location of the terminal device is not within the cell range of the source cell, the first cell is determined as neither a candidate cell nor the source cell. The method further comprises: performing re-establishment in the first cell.

11. The method according to any one of claims 7 to 9, characterized in that, If the access or handover failure occurs in the second candidate cell, the method further comprises: generating a second report, wherein the second report comprises one or more of the following information: cell information of an access failure cell, a time period information from receiving the second CHO configuration information to a handover trigger, a time period information from the handover trigger to the access failure, a time period information from the access failure to a connection recovery, a time period information from the connection recovery to reporting the second report, a time period information from the access failure to reporting the second report, time information at the access failure, location information of the terminal device at the access failure, signal quality of the source cell and / or each candidate cell; reporting the second report to the first network device.

12. A communications device, characterized by The apparatus comprises units for performing each step of the method of any one of claims 1 to 6, or units for performing each step of the method of any one of claims 7 to 11.

13. A communications device, characterized by The apparatus comprises at least one processor coupled to at least one memory: The at least one processor is configured to execute a computer program or instructions stored in the at least one memory, so that the apparatus performs the method of any one of claims 1 to 6, or so that the apparatus performs the method of any one of claims 7 to 11.

14. A computer-readable storage medium, characterized in that, A computer program product for storing instructions that, when executed by a computer, cause the computer to implement the method of any one of claims 1 to 6, or cause the computer to implement the method of any one of claims 7 to 11.

15. A communications device, characterized by comprising a processor and an interface circuit; the interface circuit for interfacing code instructions to the processor; the processor for running the code instructions to perform the method of any one of claims 1 to 6, or the processor for running the code instructions to perform the method of any one of claims 7 to 11.

16. A computer program product, characterised in that, when a computer reads and executes the computer program product, the computer is caused to perform the method of any one of claims 1 to 6, or the method of any one of claims 7 to 11.

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