Switching method and device based on TTT, communication system and storage medium

Abstract

The invention provides a TTT-based switching method and device, a communication system and a storage medium. The method can be applied to the technical field of wireless communication. In the scheme, the terminal equipment can obtain the moving speed measured by the L1 layer and the adjacent region load and the business service quality requirement measured by the L3 layer, and reports the data to the source base station, so that the source base station can dynamically adjust the TTT according to the data, and the network adaptability is improved. For example, in a high-speed moving scene, the switching delay is reduced by shortening the TTT; when the load is low, the TTT is prolonged, so that the signaling overhead can be reduced, and resource waste caused by static configuration is avoided. Besides, the terminal equipment can predict future resource requirements based on historical data and trigger the target base station to perform dynamic resource pre-allocation on the terminal equipment in advance, so that the reserved resource access cell is directly used, the traditional random access process is skipped, the negotiation time during switching is reduced, and seamless switching is realized.

Description

Technical Field

[0001] This application relates to the field of wireless communication technologies, and in particular, to a handover method, apparatus, communication system, and storage medium based on time to trigger (TTT). Background Art

[0002] With the development of high-speed mobile terminals such as high-speed trains and in-vehicle devices, optimizing handover robustness becomes particularly important. In high-speed mobile scenarios, when the channel quality of the source cell drops sharply, if the traditional handover (HO) method is used to trigger the handover by the source base station, handover may occur too late, resulting in handover failure.

[0003] Related technologies have proposed a Layer1 / Layer2 triggered mobility (LTM) mechanism aimed at reducing handover latency. In the LTM mechanism, the target beam or target cell can be quickly selected through event evaluation (such as LTM3 / LTM5). To avoid overly frequent event-triggered reports, TTT can be applied during LTM event evaluation. After the timing duration of the timer reaches TTT, the terminal device sends a measurement report to the source base station. However, if TTT is statically configured by the network device, it may lead to inaccurate handover decisions. For example, in high-speed mobile scenarios, a fixed TTT may cause handover to occur too early or too late, resulting in ping-pong effects or service interruptions. Summary of the Invention

[0004] This application provides a handover method, apparatus, communication system, and storage medium based on TTT to solve the technical problem that a fixed TTT leads to inaccurate handover decisions, resulting in ping-pong effects or service interruptions.

[0005] To achieve the above object, this application adopts the following technical solutions: In a first aspect, a handover method based on TTT is provided. This method can be executed, for example, by a terminal device, or by a component (such as a circuit, chip, or chip system, etc.) configured in the terminal device, or by a logic module or software that can implement all or part of the functions of the terminal device. The following description is given by taking the terminal device as an example.

[0006] The method may include: the terminal device sending a MAC CE to the source base station, where the MAC CE includes a first field indicating the moving speed of the terminal device, a second field indicating the load of the neighboring cell, and a third field indicating the service quality of service requirement. The first field, the second field, and the third field are used to determine the TTT; the terminal device receiving a first TTT from the source base station; and when the measurement result at L1 meets the event condition and the timing duration of the timer reaches the first TTT, the terminal device sending a measurement report to the source base station, where the measurement report may be used to trigger a cell handover.

[0007] Among the beneficial effects of the above solution, the terminal device can obtain the moving speed measured at L1 layer, the load of the neighboring cell measured at L3 layer, and the service quality of service requirement, and report these data to the source base station. Thus, the source base station can dynamically adjust the TTT according to these data, so that the terminal device can trigger a handover decision based on the LTM event and the optimized value of the TTT. For example, in a high-speed moving scenario, by shortening the TTT, the handover delay can be reduced; in a low-load situation, by extending the TTT, the signaling overhead can be reduced, and the resource waste caused by static configuration can be avoided.

[0008] In a possible implementation, the moving speed of the terminal device is determined by L1 measurement; the load of the neighboring cell is determined by L3 measurement; the service quality of service requirement is determined by L3 measurement. It can be understood that by fusing the L1 measurement data and the L3 measurement data, the data diversity can be increased, making the optimized value of the TTT more accurate.

[0009] In a possible implementation, when the first field is set to different coding values, it represents different moving speeds; when the second field is set to different coding values, it represents different loads of the neighboring cells; when the third field is set to different coding values, it represents different service quality of service requirements. It can be understood that in the MAC CE, the corresponding coding values can be set according to the specific numerical values or types of the data indicated by each field, so that the source base station can parse the corresponding information based on the coding values of each field, and then dynamically adjust the TTT.

[0010] In a possible implementation, the first field, the second field, and the third field are consecutive fields, and the data lengths of the first field, the second field, and the third field are all 2 bits. It can be understood that after classifying the moving speed, the load of the neighboring cell, and the service requirement, the number of bits required for each type of information is relatively small. For example, 2 bits can meet the data coding requirements. In this way, one byte can be used to transmit these three types of data, and the signaling overhead is small.

[0011] In a possible implementation, the MAC CE may further include: a fourth field indicating the C-RNTI of the cell where the terminal device is located; a fifth field indicating the number of resource blocks predicted to be allocated to the terminal device; and a sixth field indicating the HARQ status. It can be understood that the terminal device cannot directly communicate with the candidate base station, and resource allocation can be coordinated by the source base station. By carrying the C-RNTI of the cell where the terminal device is located, the number of resource blocks predicted to be allocated to the terminal device, and the HARQ status in the MAC CE, it is convenient for the target cell to reserve resources for the terminal device in advance.

[0012] In a possible implementation, the fourth field, the fifth field, and the sixth field are consecutive fields. The data length of the fourth field is 2 bytes, the data length of the fifth field is 1 byte, and the data length of the sixth field is 2 bits. It can be understood that by combining and transmitting the data indicated by the first field to the fourth field through one MAC CE, the signaling overhead in the air interface can be reduced, and the additional delay introduced by multiple signaling interactions can be avoided.

[0013] In a possible implementation, the method may further include: the terminal device predicting the number of resource blocks to be allocated to the terminal device based on the historical data of the terminal device. It can be understood that the traditional CSI measurement and handover decision mechanism may be outdated, resulting in a lag in handover decisions and redundant resource reservation. The historical data of the terminal device can assist in judging the number of resource blocks required in the future. Therefore, the terminal device can predict the number of resource blocks required in the future through historical data.

[0014] In a possible implementation, receiving the first TTT from the source base station may include: the terminal device receiving an RRC message from the source base station. The RRC message may include the first TTT and pre-configuration information of at least one candidate cell. The pre-configuration information may be used to indicate the resources allocated to the terminal device. For example, the pre-configuration information includes: the coded frequency points of the CSI-RS, the coded period of the CSI-RS, the port number of the CSI-RS, and the synchronization signal block index. It can be understood that the terminal device cannot directly communicate with the candidate base station, and resource allocation can be coordinated by the source base station. Therefore, the candidate base station can return the pre-configuration information to the terminal device through the source base station, enabling the terminal device to directly use the reserved resources to access the cell, skipping the traditional random access process, achieving seamless handover, and improving the access success rate.

[0015] In a possible implementation, the pre-configuration information of at least one candidate cell includes the pre-configuration information of the target cell. After sending the measurement report to the source base station, the method may further include: the terminal device receiving a cell handover instruction from the source base station; and the terminal device accessing the target cell using the pre-configuration information of the target cell in response to the cell handover instruction.

[0016] In a second aspect, a handover method based on TTT is provided. This method can be executed, for example, by a source base station, or by components (such as circuits, chips, or chip systems, etc.) configured in the source base station, or can also be implemented by a logic module or software that can implement all or part of the functions of the source base station. The following description is made with the source base station as an example.

[0017] The method may include: the source base station receives a MAC CE from a terminal device. The MAC CE may include a first field indicating the moving speed of the terminal device, a second field indicating the load of a neighboring cell, and a third field indicating the service quality requirement of the service; the source base station determines a first TTT based on the first field, the second field, and the third field; the source base station sends the first TTT to the terminal device, and the first TTT is used to determine the transmission timing of a measurement report; the source base station receives a measurement report from the terminal device; the source base station selects a target cell for the terminal device based on the measurement report.

[0018] Among the beneficial effects of the above solution, since the terminal device reports the moving speed, the neighboring cell load, and the service quality requirement of the service, the source base station can dynamically adjust the TTT according to these data, so that the terminal device can determine the transmission timing of the measurement report based on the optimized value of the TTT. By dynamically adjusting the TTT, the network adaptability can be improved. For example, in a high-speed moving scenario, by shortening the TTT, the handover delay can be reduced; in a low-load situation, by extending the TTT, the signaling overhead can be reduced, and the resource waste caused by static configuration can be avoided.

[0019] In a possible implementation manner, determining the first TTT based on the first field, the second field, and the third field may include: correcting a second TTT based on the first field, the second field, and the third field to obtain the first TTT, where the second TTT is a pre-configured fixed value. It can be understood that compared with the traditional TTT being a fixed value, by correcting the TTT, the network adaptability can be improved.

[0020] In a possible implementation manner, when the first field is set to different coding values, it represents different moving speeds; when the second field is set to different coding values, it represents different neighboring cell loads; when the third field is set to different coding values, it represents different service quality requirements of the service.

[0021] In a possible implementation manner, the first field, the second field, and the third field are consecutive fields, and the data lengths of the first field, the second field, and the third field are all 2 bits.

[0022] In a possible implementation, the MAC CE may further include: a fourth field indicating the C-RNTI of the cell where the terminal device is located; a fifth field indicating the number of resource blocks predicted to be allocated to the terminal device; and a sixth field indicating the HARQ status.

[0023] In a possible implementation, the fourth field, the fifth field, and the sixth field are consecutive fields. The data length of the fourth field is 2 bytes, the data length of the fifth field is 1 byte, and the data length of the sixth field is 2 bits.

[0024] In a possible implementation, the method may include: the source base station sending a request message to the target base station, where the request message may include the C-RNTI of the cell where the terminal device is located, the number of resource blocks predicted to be allocated to the terminal device, and the HARQ status; the source base station receiving a response message from the target base station, where the response message may include pre-configuration information of at least one candidate cell corresponding to at least one candidate base station, and the pre-configuration information is used to indicate the resources allocated to the terminal device. For example, the pre-configuration information may include: the coded frequency points of the CSI-RS, the coded period of the CSI-RS, the port number of the CSI-RS, and the synchronization signal block index.

[0025] In a possible implementation, the method may include: the source base station sending an RRC message to the terminal device, where the RRC message may include the first TTT and the pre-configuration information of at least one candidate cell. The pre-configuration information of at least one candidate cell includes the pre-configuration information of the target cell to be accessed.

[0026] In a possible implementation, after selecting a target cell for the terminal device, the method may further include: the source base station sending a cell handover instruction to the terminal device, where the cell handover instruction is used to indicate handover to the target cell.

[0027] The second aspect is the implementation on the source base station side corresponding to the first aspect. The explanations, supplements, and descriptions of the beneficial effects regarding the first aspect also apply to the second aspect and will not be elaborated here.

[0028] In a third aspect, a handover method based on TTT is provided. For example, this method may be executed by at least one candidate base station, or may also be executed by components (such as circuits, chips, or chip systems, etc.) configured in at least one candidate base station, and may also be implemented by a logic module or software that can implement all or part of the functions of the target base station. At least one candidate base station includes the target base station to which the terminal device is to be connected. The following describes it with one candidate base station as an example.

[0029] The method may include: a candidate base station receiving a request message from a source base station, where the request message may include the C-RNTI of the cell where the terminal device is located, the number of resource blocks predicted to be allocated to the terminal device, and the HARQ status; the candidate base station sending a response message to the source base station, where the response message includes pre-configuration information of a candidate cell corresponding to the candidate base station. For example, the coded frequency points of CSI-RS, the coding period of CSI-RS, the port number of CSI-RS, and the synchronization signal block index.

[0030] In the beneficial effects of the above solution, the terminal device cannot directly communicate with the target base station, and resource allocation can be coordinated by the source base station. The candidate base station can return the pre-configuration information to the terminal device through the source base station, so that the terminal device can directly use the reserved resources to access the cell, skip the traditional random access process, achieve seamless handover, and improve the access success rate.

[0031] In a fourth aspect, an electronic device is provided, which includes a transceiver module. The transceiver module is configured to: send a MAC CE to a source base station, where the MAC CE includes a first field indicating the moving speed of the terminal device, a second field indicating the load of the neighboring cell, and a third field indicating the quality of service requirement of the service, and the first field, the second field, and the third field are used to determine the TTT; receive a first TTT from the source base station; and send a measurement report to the source base station after the measurement result at L1 satisfies the event condition and the timing duration of the timer reaches the first TTT, where the measurement report can be used to trigger cell handover through event evaluation.

[0032] In a fifth aspect, an electronic device is provided, which includes a transceiver module and a processing module. The transceiver module is configured to: receive a MAC CE from a terminal device, where the MAC CE may include a first field indicating the moving speed of the terminal device, a second field indicating the load of the neighboring cell, and a third field indicating the quality of service requirement of the service. The processing module is configured to: determine a first TTT based on the first field, the second field, and the third field. The transceiver module is further configured to: send the first TTT to the terminal device, where the first TTT is used to determine the sending timing of the measurement report, and receive a measurement report from the terminal device. The processing module is further configured to: perform event evaluation based on the measurement report and select a target cell for the terminal device.

[0033] In a sixth aspect, an electronic device is provided, which includes a transceiver module. The transceiver module is configured to: receive a request message from a source base station, where the request message may include the C-RNTI of the cell where the terminal device is located, the number of resource blocks predicted to be allocated to the terminal device, and the HARQ status; and send a response message to the source base station, where the response message includes pre-configuration information of a candidate cell corresponding to a target base station. For example, the pre-configuration information may include: the coded frequency points of the CSI-RS, the coded period of the CSI-RS, the port number of the CSI-RS, and the synchronization signal block index.

[0034] The fourth, fifth, and sixth aspects are device-side implementations corresponding to the first, second, and third aspects. The explanations, supplements, and beneficial effects described for the first, second, and third aspects also apply to the fourth, fifth, and sixth aspects, and will not be elaborated here.

[0035] In a seventh aspect, a communication device is provided, which includes a processor. The processor is coupled to a memory and is configured to execute instructions or data in the memory to implement the method in any possible implementation manner of the first aspect. Optionally, the communication device further includes a memory. Optionally, the communication device further includes a communication interface, and the processor is coupled to the communication interface.

[0036] In an eighth aspect, a communication device is provided, which includes a processor. The processor is coupled to a memory and is configured to execute instructions or data in the memory to implement the method in any possible implementation manner of the second aspect. Optionally, the communication device further includes a memory. Optionally, the communication device further includes a communication interface, and the processor is coupled to the communication interface.

[0037] In a ninth aspect, a communication device is provided, which includes a processor. The processor is coupled to a memory and is configured to execute instructions or data in the memory to implement the method in any possible implementation manner of the third aspect. Optionally, the communication device further includes a memory. Optionally, the communication device further includes a communication interface, and the processor is coupled to the communication interface.

[0038] In a tenth aspect, a processor is provided, which includes: an input circuit, an output circuit, and a processing circuit. The processing circuit is configured to receive a signal through the input circuit and transmit the signal through the output circuit, so that the processor executes the method in any possible implementation manner of any aspect.

[0039] In the specific implementation process, the above-mentioned processor can be one or more chips, the input circuit can be an input pin, the output circuit can be an output pin, and the processing circuit can be transistors, gate circuits, flip-flops, and various logic circuits, etc. The input signal received by the input circuit can be received and input by, for example, but not limited to, a receiver. The signal output by the output circuit can be output to, for example, but not limited to, a transmitter and transmitted by the transmitter. Moreover, the input circuit and the output circuit can be the same circuit, and this circuit is respectively used as the input circuit and the output circuit at different times. The embodiments of the present application do not limit the specific implementation manners of the processor and various circuits.

[0040] In the eleventh aspect, a computer program product is provided. The computer program product includes: a computer program (which can also be referred to as code, or instruction). When the computer program is run, it causes the computer to execute the method in any one of the possible implementation manners in any of the above aspects.

[0041] In the twelfth aspect, a computer-readable storage medium is provided. The computer-readable storage medium stores a computer program (which can also be referred to as code, or instruction). When it runs on a computer, it causes the computer to execute the method in any one of the possible implementation manners in any of the above aspects.

[0042] In the thirteenth aspect, an embodiment of the present application provides a chip system. The chip system includes one or more processors, which are used to call and run the instructions stored in the memory from the memory, so that the methods in any of the above aspects or any of the possible implementation manners in any of the above aspects are executed. The chip system can be composed of chips, or can include chips and other discrete devices. Among them, the chip system can include an input circuit or interface for sending information or data, and an output circuit or interface for receiving information or data.

[0043] In the fourteenth aspect, a communication system is provided, which includes a terminal device, a source base station, and at least one candidate base station. The at least one candidate base station can include a target base station to which the terminal device is to be connected. In a possible implementation manner, the communication system can further include other devices for communicating with the terminal device, the source base station, and the target base station, such as LMF or AMF, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of a communication system provided by an embodiment of the present application; Figure 2 It is a schematic diagram of a communication system applicable to LTM handover provided by an embodiment of the present application; Figure 3 It is a schematic diagram of the process of L3 handover provided by an embodiment of the present application; Figure 4Schematic diagram of the LTM switching process provided by the embodiments of the present application; Figure 5 Two timing schemes based on TTT provided by the embodiments of the present application; Figure 6 Schematic diagram of the switching method based on dynamic TTT provided by the embodiments of the present application; Figure 7 Schematic diagram of the switching method based on channel prediction provided by the embodiments of the present application; Figure 8 Schematic diagram of the switching method based on dynamic TTT and channel prediction provided by the embodiments of the present application; Figure 9 Schematic block diagram of the electronic device provided by the embodiments of the present application; Figure 10 Schematic block diagram of the communication device provided by the embodiments of the present application. Detailed implementation manners

[0045] Terms such as "first" and "second" in the specification and drawings of the present application are used to distinguish different objects or different processes for the same object, rather than to describe a specific order of the objects. In addition, the terms "including" and "having" and any variations thereof mentioned in the description of the present application are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally further include other unlisted steps or units, or may optionally further include other steps or units inherent to these processes, methods, products or devices. In the embodiments of the present application, "a plurality of" includes two or more. In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. In addition, the network architecture and service scenarios described in the embodiments of the present application are for more clearly illustrating the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those of ordinary skill in the art know that with the evolution of the network architecture and the emergence of new service scenarios, the technical solutions provided by the embodiments of the present application are equally applicable to similar technical problems.

[0046] The technical solutions provided by the embodiments of this application can be applied to various communication systems, such as: Global System for Mobile Communications (GSM) system, General Packet Radio Service (GPRS), Wireless Local Area Network (WLAN), Long Term Evolution (LTE) system, LTE Frequency Division Duplex (FDD) system, LTE Time Division Duplex (TDD), Sidelink communication system, Universal Mobile Telecommunication System (UMTS), Worldwide Interoperability for Microwave Access (WiMAX) communication system, Non-Terrestrial Network (NTN) communication system, 5th Generation (5G) mobile communication system or NR system, etc. Among them, the 5G mobile communication system can include Non-Standalone (NSA) and / or Standalone (SA). The technical solutions provided by the embodiments of this application can also be applied to future communication systems, and the embodiments of this application do not limit this.

[0047] Figure 1 FIG. is a schematic diagram of a communication system 100 provided by an embodiment of this application.

[0048] The communication system 100 may include a network device, such as Figure 1 the network device 110 shown. The communication system 100 may also include a terminal device, such as Figure 1 the terminal device 120 shown. The network device 110 and the terminal device 120 may communicate through a wireless link.

[0049] Figure 1 Exemplarily, one network device 110 and one terminal device 120 are shown. In a possible implementation, the communication system 100 may also include multiple network devices and / or multiple terminal devices.

[0050] The network device in the embodiments of the present application may be a device on the network side such as an access network device or a core network device. The access network device is sometimes also referred to as an access node. The access network device has a wireless transceiver function and is used to communicate with the terminal device. The access network device includes, but is not limited to, the base station (base station), evolved Node B (eNodeB), transmit / receive Point (TRP) in the above communication system, the NR Node B (gNB) in the 5G mobile communication system, the next generation eNodeB (ng-eNB) in the 5G mobile communication system, the access network device or module of the open RAN (ORAN) system, the satellite in the non-terrestrial network (NTN) communication system, the base station in the future mobile communication system, or the access node in the wireless fidelity (Wi-Fi) system, etc. The access network device may also be a module or unit capable of implementing some functions of the base station. The access network device may be a macro base station, a micro base station or an indoor station, a relay node or a donor node, or a wireless controller in the cloud radio access network (CRAN) scenario. The access network device may also be a server, a wearable device or a vehicle-mounted device, etc. Multiple access network devices in the communication system may be of the same type of base station or different types of base stations. The base station may communicate directly with the terminal device or communicate with the terminal device through a relay station. The terminal device may communicate with multiple base stations in different access technologies. The embodiments of the present application do not limit the specific technologies and specific device forms adopted by the access network device.

[0051] In the embodiments of the present application, the device for implementing the functions of the network device may be the network device or a device capable of supporting the network device to implement the functions, such as a processor, a circuit, a chip or a chip system, etc. The device may be installed in the network device or used in connection with the network device.

[0052] The terminal device in the embodiments of the present application may be a wireless terminal device capable of receiving scheduling and indication information from a network device. The wireless terminal device may be a device that provides voice and / or data connectivity to a user, or a handheld device with wireless connection capabilities, or other processing devices connected to a wireless modem. For example, the terminal device may communicate with one or more core networks or the Internet via a radio access network (RAN). The terminal device may also be referred to as a terminal, user equipment (UE), mobile station, mobile terminal, etc. The terminal device can be widely used in various scenarios, such as device-to-device (D2D), vehicle to everything (V2X) communication, machine-type communication (MTC), Internet of Things (IOT), ultra-reliable low-latency communication (URLLC), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grid, smart furniture, smart office, smart wearables, smart transportation, smart city, or satellite communication, etc. The terminal device may be a mobile phone, a tablet computer, a computer with wireless transceiver functions, a wearable device, a vehicle, an aircraft (such as a drone, a helicopter, an airplane), a hot air balloon, a ship, a robot, a robotic arm, or a smart home device, etc. The embodiments of the present application do not limit the form of the terminal device.

[0053] In the embodiments of the present application, the device for implementing the functions of the terminal device may be the terminal device itself, or a device capable of supporting the terminal device to implement such functions, such as a processor, a circuit, a chip, or a chip system, etc. This device may be installed in the terminal device or used in connection with the terminal device.

[0054] The access network device and / or the terminal device may be fixed or movable. The access network device and / or the terminal device may be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; may also be deployed on the water surface; or may be deployed on airplanes, balloons, and artificial satellites in the air. The embodiments of the present application do not limit the application scenarios of the access network device and the terminal device. The access network device and the terminal device may be deployed in the same scenario or different scenarios. For example, the access network device and the terminal device are both deployed on land; or the access network device is deployed on land and the terminal device is deployed on the water surface, etc., and will not be enumerated one by one.

[0055] Figure 2 It is a schematic diagram of a communication system applicable to LTM handover provided by the embodiments of the present application.

[0056] A communication system may include functional entities such as terminal devices, access network devices, and core network devices. Communication occurs between the respective functional entities through corresponding interfaces. For example, terminal devices may communicate through the proximity-based services communication 5 (PC5) interface, and a terminal device may be connected to an access network device via a gNB through the NR-Uu interface.

[0057] An access network device is a device in the access network, mainly used to implement functions such as resource scheduling, radio resource management, and radio resource control for terminal devices. For example, the access network may be a next generation radio access network (NG-RAN). The NG-RAN may include one or more access network devices, such as a gNB. A gNB is a node that provides NR user plane and control plane protocols to terminal devices. For example, a gNB may be a TRP or a transmission measurement function (TMF), etc. The access network device may communicate with the core network device in a wired or wireless manner, such as being connected to the core network through the NG-C interface. The access network device is capable of sending a positioning reference signal (PRS), receiving a sounding reference signal (SRS), and obtaining relevant measurement information.

[0058] such as Figure 2As shown, in the 5G NR system, the gNB is split into a Centralized Unit (CU) and a Distributed Unit (DU). The CU and the DU are connected via the F1 interface. The CU and the DU can be set separately, or they can also be included in the same network element, such as in a Baseband Unit (BBU). The CU is connected to one or more DUs. For example, gNB1-CU is connected to gNB1-DU1 and gNB1-DU2, and gNB2-CU is connected to gNB2-DU. A DU can cover one or more cells. For example, gNB1-DU1 covers Cell1 and Cell2, gNB1-DU2 covers Cell3 and Cell4, and gNB2-DU covers Cell5, Cell6, and Cell7. The terminal device can camp on one of the cells and be in the connected state. The terminal device can be switched from the connected state to the inactive state, i.e., the non-connected state, through the Radio Resource Control (RRC) release process. The terminal device in the non-connected state can camp on the original cell and perform uplink transmission and / or downlink transmission with the access network device in the original cell according to the transmission parameters of the terminal device in the original cell. The terminal device in the non-connected state can also move to a new cell and perform uplink transmission and / or downlink transmission with the access network device in the new cell according to the transmission parameters of the terminal device in the new cell.

[0059] In the LTM handover, the CU pre-configures candidate target cells for the terminal device in advance, and the DU sends an LTM handover command to the terminal device. The terminal device switches to the target cell based on the indication of the LTM handover command and the RRC pre-configuration. The LTM mechanism can be executed between different cells of the same base station, such as between gNB1-DU1 and gNB1-DU2; it can also be executed between different base stations, such as between gNB1-DU2 and gNB2-DU.

[0060] The core network device is mainly used for network management, control, and data transmission. The core network device can include functional entities or network elements such as Figure 2 the Access and Mobility Management Function (AMF) and the Location Management Function (LMF) as shown.

[0061] The AMF can receive location service requests related to the terminal device from the location service (LCS) entity or other network elements of the 5G core network (5G core, 5GC). Alternatively, the AMF itself can also initiate some location services on behalf of a specific terminal device and forward the location service requests to the LMF.

[0062] The LMF is responsible for supporting different types of location services related to the terminal device, completing the calculation and feedback of location information in the network, and providing functions such as positioning process management, terminal capability acquisition, auxiliary data provision, and terminal location estimation. Specifically, it provides the following functions: supporting the location calculation of the terminal device, obtaining the downlink location measurement or location estimation from the terminal device, and obtaining the uplink location measurement from the NG-RAN. The control plane and user plane of the LMF are the enhanced serving mobile location center (E-SMLC) and the secure user plane locator platform (SLP), respectively. The LMF can interact with the NG-RAN and the terminal device through signals. For example, the LMF and the gNB or ng-eNB exchange information through new radio positioning protocol annex (NRPPa) messages, such as obtaining the configuration information of PRS and SRS, cell timing, cell location information, etc. Another example is that the LMF and the terminal device exchange terminal device capability information, auxiliary information, and measurement information through LTE positioning protocol (LPP) messages.

[0063] It should be noted that Figure 2 is only an exemplary framework diagram, Figure 2 the number of nodes, the number of cells, and the state of the terminal device included are not restricted. Except Figure 2 the functional nodes shown, other nodes such as gateway devices, application servers, etc. can also be included.

[0064] For ease of understanding the embodiments of the present application, the following briefly explains the terms involved in the embodiments of the present application. Optionally, the explanations of some terms can also refer to the explanations in the 3rd generation partnership project (3GPP) standard protocol. It should be understood that the technical terms in the embodiments of the present application are only examples and not limitations. For example, with the evolution of technology, technical terms will also change, and other technical terms should also apply to the present application in the case of the same technical meaning.

[0065] In a mobile communication network, when a terminal device is in the RRC connected state, if the terminal device moves from one base station coverage area to another base station coverage area, or the call quality deteriorates due to external interference, it is necessary to switch from the original channel to another idle channel, and this process is called handover. Currently, there are various handover implementation methods, such as Layer 3 (L3) handover, conditional handover (CHO), LTM handover, etc.

[0066] Exemplarily, Figure 3 FIG. is a schematic flow diagram of L3 handover provided by an embodiment of the present application.

[0067] Step 1, the source gNodeB sends a measurement control message to the UE through an RRC reconfiguration (RRCReconfiguration) message, such as including measurement objects (same frequency / different frequency), measurement report configuration, and measurement gap configuration, etc.

[0068] Step 2, the UE sends an RRC reconfiguration complete (RRCReconfigurationComplete) message to the source gNodeB.

[0069] Step 3, the UE performs measurements according to the received measurement control message. After the UE measures and determines that the event condition is met, it reports a measurement report to the source gNodeB. Correspondingly, the source gNodeB makes a handover strategy and target cell / frequency point decision according to the measurement result.

[0070] Step 4, the source gNodeB sends a handover request (HandoverRequest) to the gNodeB where the selected target cell is located (i.e., the target gNodeB). Correspondingly, after receiving the handover request, the target gNodeB performs admission control and allocates UE instances and transmission resources after allowing admission.

[0071] Step 5, the target gNodeB sends a handover request response (HandoverRequestAcknowledge) to the source gNodeB, allowing handover access. If some PDU Session handover access fails, the message needs to carry a list of failed protocol data unit (PDU) sessions.

[0072] Step 6, the source gNodeB sends an RRC reconfiguration (RRCReconfiguration) message to the UE, requiring the UE to perform a handover to the target cell.

[0073] Step 7, the source gNodeB sends the Packet Data Convergence Protocol (PDCP) sequence number (SN) to the target gNodeB through SN Status Transfer.

[0074] Step 8, the UE sends an RRCReconfigurationComplete message to the target gNodeB, and the air interface handover of the UE to the target cell is completed.

[0075] Step 9, the target gNodeB sends a path switch request message to the AMF to notify that the UE has changed cells. This message contains the target cell identifier and the list of transferred PDU Sessions. After receiving the message, the AMF updates the GPRS tunneling protocol user plane (GTPU) and modifies the GTPU address on the radio access network (RAN) side to the target gNodeB.

[0076] Step 10, the AMF sends a PathSwitchRequesttAcknowledge message to the target gNodeB. If the AMF indicates in the path switch request response message that the AMF fails to establish a PDU Session, the gNodeB deletes the PDU Session that fails to be established.

[0077] Step 11, the target gNodeB sends a UE Context Release message to the source gNodeB, and the source gNodeB releases the handovered user.

[0078] Step 12, after switching to the target cell, the target gNodeB sends a measurement control message to the UE through an RRCReconfiguration message.

[0079] Step 13, after receiving the RRCReconfiguration message (measurement control) sent by the target gNodeB, the UE sends an RRCReconfigurationComplete message to the target gNodeB.

[0080] In the L3 handover process, the terminal device continuously transmits measurement reports from the device itself to the source gNodeB according to the RRC protocol. The source gNodeB conducts evaluations based on these measurement reports to determine whether a handover is required and sends a handover request to the target gNodeB when a handover is needed. The source gNodeB sequentially evaluates all the measurement reports reported by each terminal device, which is a passive process and suffers from problems such as heavy evaluation burden and prone to failure of the link.

[0081] With the continuous development of 5G / 5G-A technology and the continuous enhancement of service requirements, the deployment of future networks will continuously evolve towards high frequencies. The coverage range of high-frequency cells is small, and users will face more frequent mobility processes such as cell selection, reselection, and handover. To improve the network mobility performance, mobility enhancement has become a hot topic. Related technologies have proposed the LTM mechanism, aiming to shorten the handover delay. In the LTM scenario, L1 measurement reports triggered by events (such as LTM3 / LTM5) are supported, and LTM needs to quickly select the target beam or target cell through event evaluation.

[0082] Exemplarily, Figure 4 It is a schematic diagram of the LTM handover process provided by the embodiments of the present application.

[0083] The terminal device in the RRC connected state sends a measurement report to the source gNodeB.

[0084] When the terminal device supports LTM, the source gNodeB sends an LTM cell handover request to at least one candidate gNodeB. At least one candidate gNodeB returns an LTM cell handover request response to the source gNodeB, and the LTM cell handover request response includes the configuration information of the candidate gNodeB.

[0085] The source gNodeB sends RRC reconfiguration information to the terminal device. The RRC reconfiguration information carries the configuration information of the candidate gNodeB. After the terminal device receives the configuration information of at least one candidate gNodeB, the terminal device sends an RRC reconfiguration complete message to the source gNodeB.

[0086] The terminal device performs downlink synchronization and uplink synchronization for each candidate gNodeB. During the process of performing uplink synchronization for each candidate gNodeB, if the RRC reconfiguration information indicates that the terminal device itself measures the timing advance (TA), then the terminal device can measure the timing advance of the source gNodeB and determine the timing advance of the candidate gNodeB according to the reception time difference between the source gNodeB and the candidate gNodeB; or, the source gNodeB triggers contention free random access (CFRA) through the order of the physical downlink control channel (PDCCH) to obtain the timing advance of the candidate gNodeB. The terminal device initiates CFRA to the candidate gNodeB to obtain the timing advance of the candidate gNodeB, and then the source gNodeB determines the validity of the timing advance.

[0087] After the downlink synchronization and uplink synchronization are completed, the terminal device performs L1 measurements on the source gNodeB and the candidate gNodeB to obtain L1 measurement results. When the measurement results of the L1 measurement meet the event conditions, the terminal device reports the L1 measurement report to the source gNodeB. After the terminal device reports the L1 measurement report to the source gNodeB, the source gNodeB can select a target beam or a target cell for the terminal device according to the L1 measurement report. The source gNodeB sends an LTM handover instruction to the terminal device, and the LTM handover instruction is used to indicate the handover to the target cell.

[0088] The terminal device disconnects the connection with the source gNodeB and initiates a random access channel (RACH) to the target gNodeB corresponding to the target cell, thereby completing the LTM cell handover.

[0089] In the above LTM handover, in order to avoid overly frequent event-triggered reports, TTT can be applied during the LTM event evaluation. After the timing duration of the timer reaches TTT, the terminal device sends a measurement report to the source base station.

[0090] Exemplarily, Figure 5 Two TTT-based timing schemes provided by this application.

[0091] As Figure 5 shown in (a) of [], the L1 layer directly monitors the event conditions (such as LTM3) and sends an L1 event indication to the MAC layer when the event conditions are met. The MAC layer starts the TTT timer based on the indication and generates a measurement report after the timer expires.

[0092] As Figure 5As shown in (b) therein, the L1 layer provides the measurement results of the candidate beam and the serving beam to the MAC layer. The MAC layer determines the triggering condition based on the configured event criteria and starts the TTT timer. The MAC layer continuously observes whether the triggering condition is met during the TTT timing. If it is met, a measurement report is generated after the timer expires.

[0093] However, in the above TTT-based timing scheme, the TTT of the timer is usually a fixed value statically configured by the network device, which may lead to inaccurate handover decisions. For example, in a high-speed mobile scenario, a fixed TTT may cause the handover to be too early or too late, resulting in ping-pong effects or service interruptions.

[0094] In view of this, the present application provides a handover method. This method can be applied to the communication system provided in the above embodiments, such as Figure 1 or Figure 2 the communication system shown. In this method, the terminal device can obtain the moving speed measured by the L1 layer, as well as the neighbor cell load and service quality of service requirements measured by the L3 layer, and report this data to the source base station. Thus, the source base station can dynamically adjust the TTT according to this data, improving network adaptability. For example, in a high-speed mobile scenario, by shortening the TTT, the handover delay can be reduced; in a low-load situation, by extending the TTT, the signaling overhead can be reduced, avoiding resource waste caused by static configuration. In addition, the terminal device can predict future resource requirements based on historical data and trigger the target base station to perform dynamic resource pre-allocation for the terminal device in advance, so as to directly use the reserved resources to access the cell, skip the traditional random access process, reduce the negotiation time during handover, reduce the handover delay, and achieve seamless handover.

[0095] The solution provided in the embodiments of the present application will be described in detail below with reference to the corresponding flowcharts. It can be understood that in the interaction flowcharts provided in the embodiments of the present application, the message or signaling interaction involved can use the messages or signaling in the standard, or can be newly introduced messages or signaling. The embodiments of the present application do not make specific limitations on this.

[0096] A unified description is made here. In the interaction process of the embodiments of the present application, the message or signaling interaction involved can use the messages or signaling in the standard, or can be newly introduced messages or signaling. The embodiments of the present application do not make specific limitations on this.

[0097] Figure 6 is a schematic flowchart of a handover method based on dynamic TTT according to an embodiment of the present application. It can be understood that Figure 6The terminal device in [[ ]] can be a terminal device or a device in the terminal device (such as a processor, a chip, or a chip system, etc.); Figure 6 The source base station in [[ ]] can be a source base station, such as a gNB, a TRP, a CU, a DU, or a device in the source base station (such as a processor, a chip, or a chip system, etc.).

[0098] Such as Figure 6 As shown, the method may include the following S101 to S108.

[0099] S101, the terminal device collects L1 layer measurement data and L3 layer measurement data.

[0100] In the embodiments of the present application, the terminal device may collect L1 layer measurement data and L3 layer measurement data in real time. The L1 layer measurement data may include Doppler frequency shift, and the Doppler frequency shift may be used to calculate the moving speed of the terminal device. The L3 layer measurement data may include the load of the neighboring cell and the quality of service (QoS) requirements of the service. The load of the neighboring cell is also referred to as the load of the adjacent cell and is used to evaluate the resource availability of the cell, and the service QoS requirements are used to determine the priority of handover. That is, the moving speed of the terminal device is determined by L1 measurement, the load of the neighboring cell is determined by L3 measurement, and the service QoS requirements are determined by L3 measurement.

[0101] The terminal device may aggregate the L1 layer measurement data and the L3 layer measurement data and map them to a dynamic identification code. In some embodiments, the medium access control (MAC) control element (CE) may be extended and designed, and a new logical channel ID (LCID) may be added to indicate the "MAC CE indicated by the dynamic handover policy". The newly added LCID may be selected within the reserved range standardized by 3GPP.

[0102] In some embodiments, the above-mentioned dynamic identification code may include a first field, a second field, and a third field.

[0103] The first field may be used to indicate the moving speed of the terminal device.

[0104] The second field may be used to indicate the load of the neighboring cell.

[0105] The third field may be used to indicate the service QoS requirements.

[0106] When the first field is set to different coding values, it represents different moving speeds.

[0107] When the second field is set to different coding values, it represents different loads of the neighboring cell.

[0108] When the third field is set to different coding values, it represents different service quality of service requirements.

[0109] Exemplarily, the extended design of the MAC CE is shown in Table 1. The first field, the second field, and the third field are consecutive fields in one byte. The data lengths of the first field, the second field, and the third field are all 2 bits. For example, the corresponding bit positions of the first field are Bit0-1, the corresponding bit positions of the second field are Bit2-3, and the corresponding bit positions of the third field are Bit4-5.

[0110] Table 1

[0111] The terminal device can classify the moving speed of the terminal device obtained based on the Doppler shift. For example, if the moving speed of the terminal device is less than or equal to the first speed threshold, it is classified as low speed, and the coding value of Bit0-1 is 00; if the moving speed of the terminal device is greater than the first speed threshold and less than or equal to the second speed threshold, it is classified as medium speed, and the coding value of Bit0-1 is 01; if the moving speed of the terminal device is greater than the second speed threshold, it is classified as high speed, and the coding value of Bit0-1 is 10.

[0112] The terminal device can classify the neighbor cell load. For example, if the neighbor cell load is less than or equal to the first load threshold, it is classified as low load, and the coding value of Bit2-3 is 00; if the neighbor cell load is greater than the first load threshold and less than or equal to the second load threshold, it is classified as medium load, and the coding value of Bit2-3 is 01; if the neighbor cell load is greater than the second load threshold, it is classified as high load, and the coding value of Bit2-3 is 10.

[0113] The terminal device can classify the service QoS requirements. For example, if the service QoS requirement is enhanced mobile broadband (eMBB), the coding value of Bit4-5 is 01; if the service QoS requirement is URLLC, the coding value of Bit4-5 is 10; if the service QoS requirement is other services, the coding value of Bit4-5 is 00.

[0114] After receiving the MAC CE from the terminal device, the source base station can parse the MAC CE, extract the dynamic identification code and map it to the predefined policy library on the source gNB side, and the predefined policy library is used for the source gNB side to understand the content sent by the terminal device. For example, in the dynamic identification code, the coding value of Bit0-1 being 10 indicates that the speed of the terminal device is high speed, the coding value of Bit2-3 being 00 indicates that the neighbor cell load is low load, and the coding value of Bit4-5 being 01 indicates that the service QoS requirement is eMBB.

[0115] S102, the terminal device sends a MAC CE to the source base station.

[0116] Correspondingly, the source base station receives the MAC CE from the terminal device.

[0117] The above MAC CE may include a first field for indicating the moving speed of the terminal device, a second field for indicating the load of the neighboring cell, and a third field for indicating the service QoS requirement. The first field, the second field, and the third field are used to determine the TTT.

[0118] S103, the source base station determines a first TTT based on the first field, the second field, and the third field.

[0119] The above first TTT can be used to determine the transmission timing of the measurement report.

[0120] After receiving the MAC CE from the terminal device, the source base station may parse the MAC CE and generate a dynamic TTT according to the parsed content. Taking the TTT pre-configured by the network device as the second TTT as an example, the source base station may correct the second TTT based on the first field, the second field, and the third field to obtain the first TTT.

[0121] Exemplarily, the source base station may calculate the first TTT through the following relational expression: .

[0122] Where, represents the first TTT, that is, the optimized TTT.

[0123] represents the second TTT, that is, the TTT before optimization.

[0124] is the speed factor, which is divided according to the speed. Such as high-speed scenario , medium-speed scenario , low-speed scenario . It can be understood that the faster the speed of the terminal device, the smaller the value of the speed factor. By shortening the TTT, the delay can be reduced and the handover success rate can be improved.

[0125] is the load factor. Such as the neighboring cell load is low load, ; the neighboring cell load is medium load, ; the neighboring cell load is high load, . It can be understood that the smaller the neighboring cell load, the smaller the value of the load factor. By shortening the TTT, the delay can be reduced and the handover success rate can be improved.

[0126] is the service priority weight. For example, for the URLLC service, ; for the eMBB service, ; for other services, . It can be understood that for high-priority services, by reducing the value, the latency can be reduced and the handover success rate can be improved.

[0127] S104, the source base station sends an RRC message to the terminal device, and the RRC message includes the first TTT.

[0128] Correspondingly, the terminal device receives the RRC message from the source base station.

[0129] Exemplarily, a TTT-ScalingFactors IE can be added to the RRCReconfiguration message sent from the source base station to the terminal device. The TTT-ScalingFactors IE is embedded in the existing RRC reconfiguration message structure through the Critical Extensions mechanism to ensure backward compatibility. The source base station stores the calculated optimized TTT value data in the TTT-ScalingFactors IE and sends it to the terminal device through the RRCReconfiguration message carrying the added TTT-ScalingFactors IE.

[0130] S105, when the measurement result at L1 meets the event condition (also known as the trigger condition) and the timing duration of the timer reaches the first TTT, the terminal device sends a measurement report to the source base station.

[0131] Correspondingly, the source base station receives the measurement report from the terminal device.

[0132] In some embodiments, the above event condition is pre-configured by the network device or the terminal device.

[0133] Exemplarily, the event condition may include at least one of the following: Event LTM2: The beam quality of the serving cell is lower than the absolute threshold; Event LTM3: The offset of the candidate cell beam is better than the offset of the serving cell beam; Event LTM4: The beam quality of the candidate cell is higher than the absolute threshold; Event LTM5: The beam quality of the serving cell is lower than the first absolute threshold and the beam quality of the candidate cell is higher than the second absolute threshold.

[0134] The terminal device can perform L1 measurements on the serving beam (i.e., the beam of the source base station) and at least one candidate beam (i.e., the beams of at least one candidate cell), and obtain the L1 measurement results. Among them, the L1 measurement can be a measurement of the reference signal received power (RSRP), the channel state information reference signal (CSI-RS), and / or the synchronization signal block (SSB) quality.

[0135] In a possible implementation, as shown in (a) of Figure 5 After obtaining the L1 measurement results (such as RS-1, RS-2, RS-3... RS-k), the L1 layer of the terminal device directly monitors the event conditions, and when the event conditions are met, sends an L1 event indication to the MAC layer of the terminal device, such as the L1 event indication of RS-x. Based on the L1 event indication, the MAC layer starts a timer and generates a measurement report after the timing duration of the timer reaches the first TTT. This measurement report can be used to trigger cell handover.

[0136] In a possible implementation, as shown in (b) of Figure 5 After obtaining the L1 measurement results (such as RS-1, RS-2, RS-3... RS-k), the L1 layer of the terminal device provides the L1 measurement results to the MAC layer. The MAC layer determines whether the L1 measurement results meet the pre-configured event conditions and starts a timer. The MAC layer continuously observes whether the event conditions are met during the timing. If they are met, a measurement report is generated after the timing duration of the timer reaches the first TTT. This measurement report can be used to trigger cell handover.

[0137] S106, The source base station selects a target cell for the terminal device based on the measurement report.

[0138] If the beam measurement results of one or more candidate cells among the at least one candidate cell meet the event conditions, then the measurement report sent by the terminal device to the source base station carries the one or more candidate cells, so that the source base station can use a certain candidate cell among the one or more candidate cells as the target cell.

[0139] S107, The source base station sends a cell handover instruction to the terminal device, and this cell handover instruction is used to indicate the handover to the target cell.

[0140] Correspondingly, the terminal device receives the cell handover instruction from the source base station.

[0141] In some embodiments, the cell handover instruction may be a MAC CE. The MAC CE may include the following information: timing advance (TA), transmission configuration indication state (TCI State) sequence number, resource information of CFRA, and configuration information identifier of the target cell.

[0142] S108, the terminal device executes a cell handover in response to the cell handover instruction.

[0143] In response to the cell handover instruction, the terminal device may disconnect from the source cell and access the target cell.

[0144] Regarding the problem that LTM mainly relies on L1 layer measurement data, the TTT parameter is statically configured by the network device, lacking the dynamic response ability to L3 layer measurement data, resulting in inaccurate handover decisions, the present application proposes the above-mentioned handover method based on dynamic TTT. In this method, based on the triggering mechanism of LTM events, the terminal device obtains L1 layer measurement data in real time, combines L3 layer measurement data to generate multi-dimensional decision inputs, and maps them into dynamic identification codes. The MAC layer of the source base station analyzes the received MAC CE, extracts the dynamic identification, calculates the optimized value of dynamic TTT, and sends down the optimized value of TTT through RRC signaling. In this way, the network adaptability is improved, the handover delay in high-speed scenarios is reduced, the risk of service interruption in low-speed scenarios is reduced, and the reliability is enhanced. In addition, when the load is low, by extending TTT, the signaling overhead can be reduced, and the resource waste caused by static configuration can be avoided.

[0145] The traditional channel state information (CSI) measurement and handover decision mechanism may be outdated. For example, when the terminal device is moving at a high speed (such as speed ≥ 120 km / h), the L1 layer measurement data may become invalid when reported to the MAC layer, resulting in misalignment between the precoding matrix indicator (PMI) and the resource block (RB) allocation, thus leading to lagging handover decisions and redundant resource reservation. Frequent handovers cause the target cell to perform resource reservation and release multiple times, increasing the control plane signaling overhead and resource fragmentation. To solve this problem, the present application also proposes a handover method based on channel prediction as Figure 7 shown.

[0146] It can be understood that Figure 7The terminal device in [ ] can be a terminal device or a device in the terminal device (such as a processor, a chip, or a chip system, etc.); Figure 7 The source base station in [ ] can be a source base station, such as a gNB, a TRP, a CU, a DU, or a device in the source base station (such as a processor, a chip, or a chip system, etc.); Figure 7 The candidate base station in [ ] can be a candidate base station or a device in the candidate base station (such as a processor, a chip, or a chip system, etc.).

[0147] As Figure 7 shown, the method may include the following S201 to S208.

[0148] S201, the terminal device predicts the future channel state based on historical data.

[0149] The above prediction of the future channel state may be to predict the number of resource blocks to be allocated for the terminal device in the future.

[0150] In some embodiments, the MAC CE may be extended and designed, and a new LCID is added to indicate the "MAC CE for predicting the number of resource blocks to be allocated for the terminal device in the future". The newly added LCID may be selected within the reserved range standardized by 3GPP.

[0151] In some embodiments, the above MAC CE may include a fourth field, a fifth field, and a sixth field.

[0152] The fourth field may be used to indicate the cell radio network temporary identifier (C-RNTI) of the cell where the terminal device is located. The C-RNTI is used for resource binding in the target cell.

[0153] The fifth field may be used to indicate the number of resource blocks predicted to be allocated for the terminal device.

[0154] The sixth field may be used to indicate the hybrid automatic repeat request (HARQ) status, and the HARQ status is used to implement fast retransmission. For example, the HARQ status is an acknowledgement (ACK) or a negative acknowledgement (NACK).

[0155] Exemplarily, the extended design of the MAC CE is shown in Table 2. The MAC CE includes a fourth field, a fifth field, and a sixth field. The fourth field, the fifth field, and the sixth field are consecutive fields. The data length of the fourth field is 2 bytes, the data length of the fifth field is 1 byte, and the data length of the sixth field is 2 bits.

[0156] Table 2

[0157] S202, the terminal device sends the MAC CE to the source base station.

[0158] The above MAC CE may include a fourth field for indicating the C-RNTI of the cell where the terminal device is located, a fifth field for indicating the number of resource blocks predicted to be allocated to the terminal device, and a sixth field for indicating the HARQ status.

[0159] Correspondingly, the source base station receives the MAC CE from the terminal device.

[0160] S203, the source base station parses the MAC CE and triggers a policy decision.

[0161] After the source base station receives the MAC CE from the terminal device, the source base station may parse the MAC CE to obtain the C-RNTI of the cell where the terminal device is located, the number of resource blocks predicted to be allocated to the terminal device, and the HARQ status.

[0162] If the HARQ status is ACK, it indicates that the data is correct and continued transmission is allowed. The source base station executes S204 below.

[0163] If the HARQ status is NACK, it indicates that the data is incorrect. The source base station sends an instruction to the terminal device, and this instruction is used to instruct the terminal device to retransmit the MAC CE carrying the fourth field, the fifth field, and the sixth field, that is, to execute S202 again.

[0164] S204, the source base station sends a request message to at least one candidate base station.

[0165] Correspondingly, at least one candidate base station receives the request message from the source base station.

[0166] The above request message may include the C-RNTI of the cell where the terminal device is located, the number of resource blocks predicted to be allocated to the terminal device, and the HARQ status. This request message can be used to request pre-allocation of resources for the terminal device.

[0167] In some embodiments, the source base station may send a request message through the newly added Xn interface ResourcePreAllocationRequest, including the C-RNTI of the cell where the terminal device is located, the number of resource blocks predicted to be allocated to the terminal device, and the HARQ status.

[0168] S205, at least one candidate base station triggers resource block reservation and HARQ buffer synchronization.

[0169] The number of resource blocks reserved by at least one candidate base station is determined according to the number of resource blocks predicted to be allocated to the terminal device in the request message. For example, the number of resource blocks reserved is equal to the number of resource blocks predicted to be allocated to the terminal device.

[0170] S206, at least one candidate base station sends a response message to the source base station.

[0171] Correspondingly, the source base station receives the response message from at least one candidate base station.

[0172] The above response message may include pre-configuration information of at least one candidate cell corresponding to at least one candidate base station, and the pre-configuration information may be used to indicate the resources allocated to the terminal device. For example, the pre-configuration information may include: the coded frequency point of CSI-RS, the coded period of CSI-RS, the port number of CSI-RS, and the SSB index. Among them, the coded frequency point of CSI-RS is used to represent the frequency domain position of the candidate base station CSI-RS.

[0173] In some embodiments, the source base station may return a response message through the newly added Xn interface ResourcePreAllocationRequest, including the pre-configuration information of at least one candidate cell corresponding to at least one candidate base station.

[0174] S207, the source base station sends an RRC message to the terminal device.

[0175] Correspondingly, the terminal device receives the RRC reconfiguration message from the source base station.

[0176] The above RRC message may include the pre-configuration information of at least one candidate cell.

[0177] In some embodiments, a targetCell-CSI-RS-Config field is newly added to the RRC reconfiguration message RRCReconfiguration, and the targetCell-CSI-RS-Config field contains pre-configuration information, such as the coded frequency point of CSI-RS, the coded period of CSI-RS, the port number of CSI-RS, and the SSB index.

[0178] S208, the terminal device uses the pre-configuration information of the target cell to access the target cell.

[0179] The above-mentioned target cell is one of at least one candidate cell, and the pre-configuration information of the at least one candidate cell includes the pre-configuration information of the target cell.

[0180] Different from the LTM handover process shown in Figure 4 , in S208, the terminal device can directly use the pre-configuration information of the target cell to access the target cell, skipping the traditional random access process to achieve seamless handover.

[0181] Regarding the problem in LTM that due to the invalidation of L1 layer measurement data when reported to the MAC layer, the PMI and resource block allocation are inaccurate, resulting in delayed handover decision and redundant resource reservation, the present application proposes the above-mentioned handover method based on channel prediction. In this method, the terminal device and the target base station cannot communicate directly, and resource allocation can be coordinated by the source base station. On the one hand, the terminal device can predict future resource requirements based on historical data, and by carrying the C-RNTI of the cell where the terminal device is located, the number of resource blocks predicted to be allocated to the terminal device, and the HARQ status in the MAC CE, it can facilitate the target cell to perform dynamic resource pre-allocation for the terminal device in advance. On the other hand, the candidate base station can return the pre-configuration information to the terminal device through the source base station, so that the terminal device can directly use the reserved resources to access the cell, skipping the traditional random access process, reducing the negotiation time during handover, reducing handover delay, and achieving seamless handover. The L1 layer measurement data quickly feedbacks the signal quality, the MAC layer allocates resources in advance, enhancing real-time performance, combined with advance prediction, reducing redundant resource occupancy and reducing transmission signaling overhead.

[0182] The above-mentioned embodiments respectively introduce Figure 6 the handover method based on dynamic TTT, and introduce Figure 7 the handover method based on channel prediction. These two methods are both solutions proposed for the problems existing in LTM, and have the following common points: 1. The MAC CE is extended and designed, and the MAC CE is sent to the source base station; 2. The source base station sends an RRC message to the terminal device. Based on this, the present application also proposes a handover method after combining these two methods.

[0183] As Figure 8 shown, this method may include the following S301 to S312.

[0184] S301, the terminal device collects L1 layer measurement data and L3 layer measurement data, and predicts the future channel state based on historical data.

[0185] The above-mentioned "L1 layer measurement data" may include Doppler frequency shift, which can be used to calculate the moving speed of the terminal device; the "L3 layer measurement data" may include the load of neighboring cells and service QoS requirements; the "prediction of future channel state" may be the prediction of the number of resource blocks to be allocated to the terminal device in the future.

[0186] In some embodiments, the MAC CE can be extended and designed, and a new LCID is added to indicate the MAC CE. The MAC CE may include a first field, a second field, a third field, a fourth field, a fifth field, and a sixth field.

[0187] The first field can be used to indicate the moving speed of the terminal device.

[0188] The second field can be used to indicate the load of neighboring cells.

[0189] The third field can be used to indicate the service QoS requirements.

[0190] The fourth field can be used to indicate the C-RNTI of the cell where the terminal device is located.

[0191] The fifth field can be used to indicate the number of resource blocks predicted to be allocated to the terminal device.

[0192] The sixth field can be used to indicate the HARQ status.

[0193] Exemplarily, the extended design of the MAC CE is shown in Table 3. The MAC CE includes two parts: a dynamic identifier for calculating TTT and resource pre-allocation. The dynamic identifier can be 1 byte and at least includes a first field, a second field, and a third field, and the data lengths of the first field, the second field, and the third field are all 2 bits. The resource pre-allocation may include a fourth field, a fifth field, and a sixth field. The data length of the fourth field is 2 bytes, the data length of the fifth field is 1 byte, and the data length of the sixth field is 2 bits.

[0194] Table 3

[0195] For the specific implementation manner of S301, reference can be made to the descriptions of S101 and S201 in the above embodiments, which will not be elaborated here.

[0196] S302, the terminal device sends the MAC CE to the source base station.

[0197] Correspondingly, the source base station receives the MAC CE from the terminal device.

[0198] The above MAC CE may include: a first field for indicating the moving speed of the terminal device, a second field for indicating the load of the neighboring cell, a third field for indicating the service QoS requirement, a fourth field for indicating the C-RNTI of the cell where the terminal device is located, a fifth field for indicating the number of resource blocks predicted to be allocated to the terminal device, and a sixth field for indicating the HARQ status. It can be understood that by combining the transmission of the dynamic identifier and resource pre-allocation through one MAC CE, the signaling overhead of the air interface can be reduced, and the additional delay introduced by multiple signaling interactions can be avoided.

[0199] It should be noted that the above embodiments are described by taking the transmission of the dynamic identifier and resource pre-allocation through the MAC CE as an example. Compared with L3, the MAC CE is closer to the physical layer, has high real-time performance, and can reduce the signaling overhead. In other embodiments, the dynamic identifier and resource pre-allocation can also be sent through the RRC signaling of L3.

[0200] S303, the source base station parses the MAC CE, determines the first TTT based on the parsing result, and triggers the policy decision.

[0201] On the one hand, the source base station can calculate the first TTT based on the parsing results of the first field, the second field, and the third field. Reference can be made to the description of S103 in the above embodiments, and details are not repeated here.

[0202] On the other hand, the source base station can trigger the policy decision based on the parsing results of the fourth field, the fifth field, and the sixth field. Reference can be made to the description of S203 in the above embodiments, and details are not repeated here.

[0203] S304, the source base station sends a request message to at least one candidate base station.

[0204] Correspondingly, at least one candidate base station receives the request message from the source base station.

[0205] The above request message may include the C-RNTI of the cell where the terminal device is located, the number of resource blocks predicted to be allocated to the terminal device, and the HARQ status. This request message can be used to request resource pre-allocation for the terminal device.

[0206] S305, at least one candidate base station triggers resource block reservation and HARQ buffer synchronization.

[0207] S306, at least one candidate base station sends a response message to the source base station.

[0208] Correspondingly, the source base station receives the response message from at least one candidate base station.

[0209] The above response message may include pre-configuration information of at least one candidate cell corresponding to at least one candidate base station, and the pre-configuration information may be used to indicate the resources allocated to the terminal device. For example, the pre-configuration information may include: the coded frequency points of CSI-RS, the coded period of CSI-RS, the port number of CSI-RS, and the SSB index. Among them, the coded frequency points of CSI-RS are used to represent the frequency domain position of the CSI-RS of the candidate base station.

[0210] For the specific implementation manners of S304 to S306, reference may be made to the descriptions of S204 to S206 in the above embodiments, which will not be elaborated here.

[0211] S307, the source base station sends an RRC reconfiguration message to the terminal device.

[0212] Correspondingly, the terminal device receives the RRC reconfiguration message from the source base station.

[0213] The above RRC reconfiguration message may include the first TTT obtained through S303, and the pre-configuration information of at least one candidate cell obtained through S303 to S306. It can be understood that by combining and sending the first TTT and the pre-configuration information of at least one candidate cell through one RRC reconfiguration message, the signaling overhead of the air interface can be reduced, and the additional delay introduced by multiple signaling interactions can be avoided.

[0214] For the specific implementation manner of S307, reference may be made to the descriptions of S104 and S207 in the above embodiments, which will not be elaborated here.

[0215] S308, the terminal device sends an RRC reconfiguration complete message to the source base station.

[0216] Correspondingly, the source base station receives the RRC reconfiguration complete message from the terminal device.

[0217] The above RRC reconfiguration complete message is used to indicate that the RRC reconfiguration is completed.

[0218] S309, when the measurement result at L1 meets the event condition and the timing duration of the timer reaches the first TTT, the terminal device sends a measurement report to the source base station.

[0219] Correspondingly, the source base station receives the measurement report from the terminal device.

[0220] For the specific implementation manner of S309, reference may be made to the description of S105 in the above embodiments, which will not be elaborated here.

[0221] S310, the source base station selects a target cell for the terminal device based on the measurement report.

[0222] If the beam measurement results of one or more candidate cells in at least one candidate cell meet the event condition, the measurement report sent by the terminal device to the source base station carries the one or more candidate cells, so that the source base station can use a certain candidate cell among the one or more candidate cells as the target cell.

[0223] For the specific implementation manner of S310, reference may be made to the description of S106 in the foregoing embodiments, which will not be elaborated here.

[0224] S311, the source base station sends a cell handover instruction to the terminal device, and the cell handover instruction is used to indicate handover to the target cell.

[0225] Correspondingly, the terminal device receives the cell handover instruction from the source base station.

[0226] For the specific implementation manner of S311, reference may be made to the description of S107 in the foregoing embodiments, which will not be elaborated here.

[0227] S312, the terminal device uses the preconfigured information of the target cell to access the target cell.

[0228] The foregoing target cell is one cell among at least one candidate cell, and the preconfigured information of the at least one candidate cell includes the preconfigured information of the target cell.

[0229] In the foregoing method provided in this application, the terminal device cannot directly communicate with the target base station, and resource allocation can be coordinated by the source base station. On the one hand, by carrying the C-RNTI of the cell where the terminal device is located, the number of resource blocks predicted to be allocated to the terminal device, and the HARQ status in the MAC CE, it is convenient for the target cell to reserve resources for the terminal device in advance. On the other hand, the candidate base station can return the preconfigured information to the terminal device through the source base station, so that the terminal device can directly use the reserved resources to access the cell, skip the traditional random access process, achieve seamless handover, and improve the access success rate.

[0230] It should be understood that Figures 1 to 8 The flowchart or scenario diagram shown is only for easy understanding and does not intend to limit the embodiments of this application to the examples shown in the diagram. In fact, those skilled in the art can perform equivalent transformations based on Figures 1 to 8 the examples in, and obtain more implementation manners.

[0231] As described above in conjunction with Figures 1 to 8 , the handover method provided by the embodiments of this application has been described in detail. Next, the device embodiments of this application will be described in detail in conjunction with Figures 9 to 10 It should be understood that the communication device in the embodiments of this application can execute various handover methods in the foregoing embodiments of this application, that is, the specific working processes of the following various products can refer to the corresponding processes in the foregoing method embodiments.

[0232] In the foregoing embodiments, the terminal device may execute some or all of the steps in the embodiments; the base station may execute some or all of the steps in the embodiments. These steps or operations are merely examples, and the embodiments of the present application may also execute other operations or various deformations of the operations. In addition, each step may be executed in a different order presented in the embodiments, and it is possible that not all the operations in the embodiments of the present application are to be executed. Moreover, the magnitude of the serial numbers of the steps does not mean the sequence of execution. The execution sequence of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0233] Figure 9 is a schematic block diagram of an electronic device provided by an embodiment of the present application. As Figure 9 shown, the electronic device 900 may include a transceiver module 910. The transceiver module 910 may implement corresponding communication functions, and the communication functions may be internal communication functions of the electronic device 900 or communication functions between the electronic device 900 and other devices. Optionally, the transceiver module 910 may also be referred to as a communication interface or a transceiver module. Optionally, the electronic device 900 further includes a processing module 920. The processing module 920 may implement corresponding processing functions.

[0234] Optionally, the electronic device 900 further includes a storage module, which may be used to store instructions and / or data; the processing module 920 may read the instructions and / or data in the storage module to enable the electronic device 900 to implement the foregoing method embodiments.

[0235] In a possible implementation manner, the electronic device 900 may correspond to the terminal device in the foregoing method embodiments, or be a component (such as a circuit, a chip, or a chip system, etc.) configured in the terminal device. The electronic device 900 may be used to execute the steps or processes executed by the terminal device in any of the foregoing method embodiments.

[0236] Exemplarily, the transceiver module 910 may be used to: send a MAC CE to a source base station, where the MAC CE includes a first field indicating the moving speed of the terminal device, a second field indicating the load of a neighboring cell, and a third field indicating the service quality requirement of a service, and the first field, the second field, and the third field are used to determine the TTT; receive a first TTT from the source base station; and, after the measurement result at L1 meets the event condition and the timing duration of a timer reaches the first TTT, send a measurement report to the source base station, and the measurement report may be used to trigger a cell handover through event evaluation.

[0237] The above is only an example, and the detailed steps or processes may refer to the description of the foregoing embodiments.

[0238] In another possible implementation, the electronic device 900 may correspond to the source base station in the above method embodiment, or be a component (such as a circuit, a chip, or a chip system, etc.) configured in the source base station. The electronic device 900 can be used to execute the steps or processes performed by the source base station in any of the above method embodiments.

[0239] Exemplarily, the transceiver module 910 can be used to: receive a MAC CE from a terminal device, where the MAC CE may include a first field indicating the moving speed of the terminal device, a second field indicating the load of a neighboring cell, and a third field indicating the service quality of service requirement. The processing module 920 can be used to: determine a first TTT based on the first field, the second field, and the third field. The transceiver module 910 can also be used to: send the first TTT to the terminal device, where the first TTT is used to determine the transmission timing of a measurement report, and receive a measurement report from the terminal device. The processing module 920 can also be used to: perform event evaluation based on the measurement report and select a target cell for the terminal device.

[0240] In another possible implementation, the electronic device 900 may correspond to the candidate base station in the above method embodiment, or be a component (such as a circuit, a chip, or a chip system, etc.) configured in the candidate base station. The electronic device 900 can be used to execute the steps or processes performed by the candidate base station in any of the above method embodiments.

[0241] Exemplarily, the transceiver module 910 can be used to: receive a request message from a source base station, where the request message may include the C-RNTI of the cell where the terminal device is located, the number of resource blocks predicted to be allocated to the terminal device, and the HARQ status; and, send a response message to the source base station, where the response message includes pre-configuration information of a candidate cell corresponding to the target base station. For example, the pre-configuration information may include: the coded frequency point of the CSI-RS, the coded period of the CSI-RS, the port number of the CSI-RS, and the synchronization signal block index.

[0242] The above are only examples, and for detailed steps or processes, reference may be made to the descriptions in the foregoing embodiments.

[0243] Figure 10 It is a schematic block diagram of a communication device 1000 provided by an embodiment of the present application. The communication device 1000 may be a terminal device, a source base station, or a chip, a chip system, or a processor, etc. that implements the above method. The communication device 1000 can be used to implement the method described in the above method embodiment, and for details, reference may be made to the descriptions in the above method embodiment.

[0244] Such as Figure 10As shown, the communication device 1000 may include one or more processors 1010, which may also be referred to as a processing unit or a processing module, and can implement certain control functions. The processor 1010 may be a general-purpose processor or a dedicated processor, etc. For example, it may be a baseband processor or a central processing unit. The baseband processor can be used to process communication protocols and communication data, and the central processing unit can be used to control the communication device 1000 (such as a base station, a baseband chip, a user, a user chip), execute software programs, and process data of software programs.

[0245] In a possible implementation, the processor 1010 may also store instructions and / or data, and the instructions and / or data can be run by the processor 1010, so that the communication device 1000 executes the methods described in the above method embodiments.

[0246] In another possible implementation, the communication device 1000 may include a communication interface 1020 for implementing receiving and sending functions. For example, the communication interface 1020 may be a transceiver circuit, an interface, an interface circuit, or a transceiver, etc. The transceiver circuit, interface, interface circuit, or transceiver for implementing receiving and sending functions may be separate or integrated together. The above transceiver circuit, interface, interface circuit, or transceiver can be used for reading and writing codes / data, or the above transceiver circuit, interface, interface circuit, or transceiver can be used for transmitting or delivering signals.

[0247] Optionally, the communication device 1000 may include one or more memories 1030, on which instructions may be stored, and the instructions can be run on the processor 1010, so that the communication device 1000 executes the methods described in the above method embodiments. Optionally, data may also be stored in the memory 1030. Optionally, instructions and / or data may also be stored in the processor 1010. The processor 1010 and the memory 1030 may be provided separately or integrated together.

[0248] It should be understood that in a possible implementation, the steps in the method embodiments provided in this application can be completed by the integrated logic circuit in the hardware of the processor or instructions in software form. The steps of the method disclosed in combination with the embodiments of this application can be directly embodied as being executed and completed by the hardware processor, or executed and completed by a combination of the hardware and software modules in the processor. The software module may be located in a mature storage medium in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. This storage medium is located in the memory, and the processor reads the information in the memory and combines its hardware to complete the steps of the above method. To avoid repetition, it will not be described in detail here.

[0249] An implementation mode. The communication device 1000 may correspond to the terminal device in the above method embodiment and may be used to execute each step and / or process executed by the terminal device in the above method embodiment. The processor 1010 may be used to execute the instructions stored in the memory 1030, and when the processor 1010 executes the instructions stored in the memory, the processor 1010 is used to execute each step and / or process of the above method embodiment corresponding to the terminal device.

[0250] Another implementation mode. The communication device 1000 may correspond to the source base station in the above method embodiment and may be used to execute each step and / or process executed by the source base station in the above method embodiment. The processor 1010 may be used to execute the instructions stored in the memory 1030, and when the processor 1010 executes the instructions stored in the memory, the processor 1010 is used to execute each step and / or process of the above method embodiment corresponding to the source base station.

[0251] Another implementation mode. The communication device 1000 may correspond to the candidate base station in the above method embodiment and may be used to execute each step and / or process executed by the candidate base station in the above method embodiment. The processor 1010 may be used to execute the instructions stored in the memory 1030, and when the processor 1010 executes the instructions stored in the memory, the processor 1010 is used to execute each step and / or process of the above method embodiment corresponding to the candidate base station.

[0252] It should be understood that the above processing device may be one or more chips. For example, the processing device may be a field programmable gate array (FPGA), may be an application specific integrated circuit (ASIC), may also be a system on chip (SoC), may also be a central processor unit (CPU), may also be a network processor (NP), may also be a digital signal processing circuit (DSP), may also be a micro controller unit (MCU), may also be a programmable logic device (PLD) or other integrated chips.

[0253] It can be understood that the memory 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 erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory can be a random access memory (RAM), which is 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 SDRAM (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchlink DRAM (SLDRAM), and directrambus RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0254] According to the method provided by the embodiments of the present application, the present application further provides a chip system, which includes one or more processors for calling and running instructions stored in the memory from the memory, so that the method of the above embodiments of the present application is executed. The chip system can be composed of chips or can include chips and other discrete devices. Among them, the chip system can include an input circuit or interface for sending information or data, and an output circuit or interface for receiving information or data.

[0255] According to the method provided by the embodiments of the present application, the present application further provides a communication system, which includes the foregoing terminal device, source base station, and at least one candidate base station. The at least one candidate base station includes a target base station to which the terminal device is to be connected.

[0256] According to the method provided by the embodiments of the present application, the present application further provides a computer program product, which includes: computer program code. When the computer program code runs on a computer, it causes the computer to execute each step or process performed by the terminal device, the source base station, and at least one candidate base station in any of the foregoing method embodiments.

[0257] According to the method provided by the embodiments of the present application, the present application further provides a computer-readable storage medium, which stores program code. When the program code runs on a computer, it causes the computer to execute each step or process performed by the terminal device, the source base station, and at least one candidate base station in any of the foregoing method embodiments. The computer-readable storage medium may be the above-mentioned volatile memory or non-volatile memory, or may include both volatile memory and non-volatile memory at the same time.

[0258] In the embodiments of the present application, the terms and English abbreviations are all exemplary examples given for convenience of description, and should not constitute any limitation to the present application. The present application does not exclude the possibility of defining other terms that can achieve the same or similar functions in existing or future protocols.

[0259] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, the processes or functions according to the embodiments of the present application are generated in whole or in part.

[0260] In several embodiments provided by the present application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of units is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces, and the indirect couplings or communication connections of devices or units can be in electrical, mechanical, or other forms.

[0261] It should be understood that in various embodiments of the present application, the magnitudes of the serial numbers of the processes do not mean the order of execution, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0262] In summary, the above are only the preferred embodiments of the technical solution of this application, and are not intended to limit the protection scope of this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the protection scope of this application.

Claims

1. A TTT-based handover method, characterized in that, The method includes: Sending a Media Access Control Control Element (MAC CE) to a source base station, where the MAC CE includes a first field indicating the moving speed of a terminal device, a second field indicating the load of a neighboring cell, and a third field indicating the quality of service (QoS) requirements of services. The first field, the second field, and the third field are used to determine the Time To Trigger (TTT). Receiving a first TTT from the source base station. When the measurement result at layer 1 meets the event condition and the timing duration of a timer reaches the first TTT, sending a measurement report to the source base station, where the measurement report is used to trigger cell handover.

2. The method according to claim 1, wherein: The moving speed of the terminal device is determined by layer 1 measurement. The load of the neighboring cell is determined by layer 3 measurement. The QoS requirements of services are determined by layer 3 measurement.

3. The method according to claim 1, wherein: When the first field is set to different coding values, it represents different moving speeds. When the second field is set to different coding values, it represents different loads of neighboring cells. When the third field is set to different coding values, it represents different QoS requirements of services.

4. The method according to claim 1, characterized in that, The first field, the second field, and the third field are consecutive fields, and the data lengths of the first field, the second field, and the third field are all 2 bits.

5. The method according to any one of claims 1 to 4, characterized in that, The MAC CE further includes: A fourth field indicating the Cell Radio Network Temporary Identifier (C-RNTI) of the cell where the terminal device is located. A fifth field indicating the number of resource blocks predicted to be allocated to the terminal device; and A sixth field indicating the Hybrid Automatic Repeat reQuest (HARQ) status.

6. The method according to claim 5, characterized in that The fourth field, the fifth field, and the sixth field are consecutive fields. The data length of the fourth field is 2 bytes, the data length of the fifth field is 1 byte, and the data length of the sixth field is 2 bits.

7. The method according to claim 5, wherein The method further includes: Predicting the number of resource blocks to be allocated to the terminal device based on the historical data of the terminal device.

8. The method according to claim 5, characterized in that The receiving the first TTT from the source base station includes: Receiving a Radio Resource Control (RRC) message from the source base station, where the RRC message includes the first TTT and pre-configuration information of at least one candidate cell, and the pre-configuration information is used to indicate the resources allocated to the terminal device.

9. The method according to claim 8, characterized in that, The pre-configuration information includes: the coded frequency points of the Channel State Information Reference Signal (CSI-RS), the coding period of the CSI-RS, the port number of the CSI-RS, and the Synchronization Signal Block (SSB) index.

10. The method according to claim 8, characterized in that, The pre-configuration information of the at least one candidate cell includes the pre-configuration information of the target cell. After sending the measurement report to the source base station, the method further includes: Receiving a cell handover instruction from the source base station. In response to the cell handover instruction, accessing the target cell using the pre-configuration information of the target cell.

11. A switching method based on TTT, characterized in that, The method includes: Receive a MAC CE from a terminal device, where the MAC CE includes a first field indicating the moving speed of the terminal device, a second field indicating the load of a neighboring cell, and a third field indicating the quality of service requirement for services; Determine a first TTT based on the first field, the second field, and the third field; Send the first TTT to the terminal device, where the first TTT is used to determine the transmission timing of a measurement report; Receive the measurement report from the terminal device; Select a target cell for the terminal device based on the measurement report.

12. The method according to claim 11, wherein The determining the first TTT based on the first field, the second field, and the third field includes: Modifying a second TTT based on the first field, the second field, and the third field to obtain the first TTT, where the second TTT is a pre-configured fixed value.

13. The method according to claim 11, wherein, When the first field is set to different coding values, it represents different moving speeds; When the second field is set to different coding values, it represents different loads of neighboring cells; When the third field is set to different coding values, it represents different quality of service requirements for services.

14. The method according to claim 11, wherein The first field, the second field, and the third field are consecutive fields, and the data lengths of the first field, the second field, and the third field are all 2 bits.

15. The method according to claim 11, wherein The MAC CE further includes: A fourth field indicating the C-RNTI of the cell where the terminal device is located; A fifth field indicating the number of resource blocks predicted to be allocated to the terminal device; and, A sixth field indicating the HARQ status.

16. The method according to claim 15, characterized in that The fourth field, the fifth field, and the sixth field are consecutive fields, the data length of the fourth field is 2 bytes, the data length of the fifth field is 1 byte, and the data length of the sixth field is 2 bits.

17. The method according to claim 15, wherein The method includes: Send a request message to at least one candidate base station, where the request message includes the C-RNTI of the cell where the terminal device is located, the number of resource blocks predicted to be allocated to the terminal device, and the HARQ status; Receive a response message from the at least one candidate base station, where the response message includes pre-configuration information of at least one candidate cell corresponding to the at least one candidate base station, and the pre-configuration information is used to indicate the resources allocated to the terminal device.

18. The method according to claim 17, characterized in that, The pre-configuration information includes: the coded frequency point of CSI-RS, the coded period of CSI-RS, the port number of CSI-RS, and the synchronization signal block index.

19. The method according to claim 17, characterized in that, The method includes: Send an RRC message to the terminal device, where the RRC message includes the first TTT and the pre-configuration information of the at least one candidate cell, and the pre-configuration information of the at least one candidate cell includes the pre-configuration information of the target cell to be accessed.

20. The method according to any one of claims 11 to 19, characterized in that After selecting the target cell for the terminal device, the method further includes: Send a cell handover instruction to the terminal device, where the cell handover instruction is used to indicate handover to the target cell.

21. A communication device ， Characterized in that the device comprises at least one processor, the at least one processor is coupled to a memory, the memory stores programs or instructions, and the processor executes the programs or instructions such that the device is configured to perform the method according to any one of claims 1 to 10, or perform the method according to any one of claims 11 to 20.

22. A communication system, characterized in that, The communication system includes a terminal device, a source base station, and at least one candidate base station; wherein, the terminal device is configured to execute the method according to any one of claims 1 to 10, and the source base station is configured to execute the method according to any one of claims 11 to 20.

23. A computer-readable storage medium, characterized in that, A computer program or instruction is stored on the computer-readable storage medium, and when the computer program or instruction is executed, it causes the computer to execute the method according to any one of claims 1 to 10, or execute the method according to any one of claims 11 to 20.

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