Handover method and apparatus

Abstract

The application provides a switching method and device. The switching method comprises: receiving configuration information, the configuration information being used for configuring a target cell, the configuration information comprising random access configuration information, the random access configuration information being used for performing an uplink synchronization process with the target cell; receiving a switching command, the switching command being used for instructing switching to the target cell; and performing an access process to the target cell according to the switching command, the access process being completed through a random access free process. Before receiving the switching command, the terminal device can receive the random access configuration information of the target cell, so as to facilitate the terminal device to perform the uplink synchronization process with the target cell. In this way, after receiving the switching command, the terminal device can complete the access to the target cell through the random access free process, and does not need to perform the uplink synchronization process after receiving the switching command, thereby reducing the interruption time of the terminal device in the switching process.

Description

Technical Field

[0001] This application relates to the field of communications, and particularly to handover methods and apparatus in the field of communications. Background Technology

[0002] In wireless communication, traditional cell handover primarily relies on reactive handover. In this mechanism, the terminal device measures the serving cell and / or neighboring cells based on the measurement configuration sent by the base station and reports the measurement results to the base station. The base station then makes a handover decision based on these results and issues a handover command to the terminal device, triggering the handover. This handover mechanism is suitable for scenarios with macro cells and slow-moving terminal devices. However, in certain scenarios, such as high-moving terminal devices, densely deployed cells, or latency-sensitive services, this handover mechanism may lead to poor handover performance, such as premature / late handover or the ping-pong effect.

[0003] Artificial intelligence (AI)-based handover mechanisms can effectively improve handover performance and reduce measurement overhead. The main principle of AI-based handover mechanisms is to predict other measurement results based on one or more of the following: historical measurement results, the terminal device's movement trajectory, movement speed, big data, or communication maps. The network can then make handover decisions based on these predicted results. In this AI-based handover mechanism, the base station can pre-determine the handover time based on the predicted measurement results, but the terminal device only begins the handover process after the handover time arrives. During the handover process, the terminal device may disconnect from the source base station, and the time from disconnection to re-establishment of connection with the target base station (which can be called handover latency or interruption duration) remains unchanged. Summary of the Invention

[0004] This application provides a handover method and apparatus to reduce the downtime of terminal devices during the handover process.

[0005] Firstly, this application provides a switching method, which can be executed by a first communication device. The first communication device can be a terminal device, or a circuit or chip applicable to the terminal device (such as a modem chip, also known as a baseband chip, or a system-on-chip (SoC) chip or system-in-package (SIP) chip containing a modem core), and this application does not limit it in this regard.

[0006] For example, the method includes: receiving configuration information for configuring a target cell, the configuration information including random access configuration information for performing an uplink synchronization process with the target cell; receiving a handover command for instructing a handover to the target cell; and performing an access process to the target cell according to the handover command, the access process being completed through a non-random access procedure.

[0007] In the above scheme, the terminal device can receive the random access configuration information of the target cell before receiving the handover command, so as to perform the uplink synchronization process with the target cell. In this way, after receiving the handover command, the terminal device can complete the access to the target cell without the random access process, without having to perform the uplink synchronization process after receiving the handover command, thereby reducing the interruption time of the terminal device during the handover process.

[0008] In conjunction with the first aspect, in some possible implementations of the first aspect, before receiving the above configuration information, first information is sent, which is used to indicate at least one of the following: a predicted measurement result of a first cell, the first cell including the above target cell; or a predicted measurement event related to the first cell, the first cell including the above target cell.

[0009] Optionally, the aforementioned first community may also include a service community.

[0010] By reporting the predicted measurement results and / or related measurement events of the first cell from the terminal equipment, the access network equipment can make handover decisions based on this information. This not only reduces measurement overhead but also effectively improves handover performance, such as reducing premature / late handovers and minimizing ping-pong handovers between cells.

[0011] In conjunction with the first aspect, in some possible implementations of the first aspect, the above configuration information may also include random access-free configuration information, or the above switching command may include random access-free configuration information, which may include configured grant (CG) configuration information and / or dynamic grant (DG) configuration information.

[0012] In the above scheme, after receiving the handover command, the terminal device can execute the no-random access procedure to the target cell. The no-random access configuration information used for the no-random access procedure can be carried in / carried in the handover command, or it can be carried in the configuration information before the handover command. This allows the terminal device to obtain the configuration information used in the no-random access procedure in advance, and at the same time, it helps to improve the flexibility of the access network device in issuing no-random access configuration information.

[0013] In conjunction with the first aspect, in some possible implementations of the first aspect, the above method further includes: sending a preamble based on random access configuration information before performing the access procedure to the target cell according to the handover command.

[0014] In other words, before the terminal device performs the access process to the target cell, it performs uplink synchronization with the target cell. This saves the time that the terminal device spends performing the uplink synchronization process during the handover, which helps to reduce the interruption time during the handover process.

[0015] In conjunction with the first aspect, in some possible implementations of the first aspect, the above method further includes: receiving a first message, which is used to respond to the above preamble, the first message carrying a timing advance (TA).

[0016] Optionally, the first message received by the terminal device comes from the access network equipment to which the target cell belongs.

[0017] In conjunction with the first aspect, in some possible implementations of the first aspect, the aforementioned switching command includes TA.

[0018] The TA can be carried in the handover command, so that the terminal device can receive the TA from the access network device to which the source cell belongs, thus eliminating the need to wait for a random access response from the access network device to which the target cell belongs, and reducing the interruption time between the terminal device and the access network device to which the source cell belongs.

[0019] Secondly, this application provides a switching method that can be executed by a second communication device. The second communication device can be an access network device, or a circuit or chip applicable to the access network device (such as a modem chip, also known as a baseband chip, or a SoC chip or SIP chip containing a modem core), and this application does not limit it in this regard.

[0020] For example, the method includes: sending configuration information for configuring a target cell, the configuration information including random access configuration information for performing an uplink synchronization process with the target cell; and sending a handover command for instructing a handover to the target cell.

[0021] In the above scheme, the access network device can send the random access configuration information of the target cell before sending the handover command, so that the terminal device can perform the uplink synchronization process with the target cell in advance. For example, the uplink synchronization process with the target cell can be performed before receiving the handover command or before performing the access process to the target cell. This helps to reduce the interruption time of the terminal device during the handover process.

[0022] In conjunction with the second aspect, in some possible implementations of the second aspect, the method further includes: receiving first information before sending configuration information, the first information indicating at least one of the following: a predicted measurement result of a first cell, the first cell including the target cell; or a predicted measurement event related to the first cell, the first cell including the target cell.

[0023] In conjunction with the second aspect, in some possible implementations of the second aspect, the above method further includes: determining the above configuration information based on the first information.

[0024] In conjunction with the second aspect, in some possible implementations of the second aspect, the above configuration information may also include random access-free configuration information, or the above switching command may include random access-free configuration information, which may include CG configuration information and / or DG configuration information.

[0025] In conjunction with the second aspect, in some possible implementations of the second aspect, the aforementioned switching command includes TA.

[0026] It should be understood that the second aspect of this application corresponds to the technical solution of the first aspect of this application, and the possible implementations of the second aspect and the possible implementations of the first aspect achieve similar beneficial effects, which will not be repeated here.

[0027] Thirdly, this application provides another switching method, which can be executed by a first communication device. The first communication device can be a terminal device, or a circuit or chip applicable to a terminal device (such as a modem chip, also known as a baseband chip, or a SoC chip or SIP chip containing a modem core), and this application does not limit it.

[0028] For example, the method includes: receiving a handover command, the handover command instructing a terminal device to handover to a target cell, the handover command including random access configuration information and second information, the second information being used to indicate a first time; before the first time, performing an uplink synchronization process with the target cell according to the random access configuration information; and performing an access process to the target cell according to the second information at the first time.

[0029] Optionally, the handover command may also include reference signal configuration information of the target cell, which is used to perform the downlink synchronization process with the target cell.

[0030] In the above scheme, the terminal device can perform the uplink synchronization process and / or downlink synchronization process with the target cell before the first moment indicated by the access network device (i.e. the moment of handover), which helps to reduce the interruption time in the subsequent handover process (such as the time required for the uplink / downlink synchronization process).

[0031] In conjunction with the third aspect, in some possible implementations of the third aspect, the method further includes: before receiving the handover command, sending first information, the first information indicating at least one of the following: a predicted measurement result of a first cell, the first cell including the target cell; or a predicted measurement event related to the first cell, the first cell including the target cell.

[0032] By reporting the predicted measurement results and / or related measurement events of the first cell by the terminal equipment, the access network equipment can make handover decisions based on this information. This not only reduces measurement overhead but also effectively improves handover performance, such as reducing premature / late handovers and reducing ping-pong handovers between cells.

[0033] In conjunction with the third aspect, in some possible implementations of the third aspect, the aforementioned handover command also includes random access-free configuration information of the target cell, which includes CG configuration information and / or DG configuration information.

[0034] The aforementioned random access-free configuration information can be used by the terminal device to perform the random access-free process with the target cell at the first moment. In this way, after the first moment, the time for the terminal device to perform the random access process is saved, which helps to reduce the interruption time during the handover process.

[0035] In conjunction with the third aspect, in some possible implementations of the third aspect, the above-mentioned execution of the access procedure to the target cell at a first moment based on the second information includes: executing the access to the target cell at a first moment based on the second information through a random access procedure.

[0036] Access to the target cell is performed without a random access procedure at the first moment. This saves the time that the terminal device needs to perform a random access procedure after the first moment, which helps to reduce the interruption time during the handover process.

[0037] In conjunction with the third aspect, in some possible implementations of the third aspect, the aforementioned uplink synchronization process with the target cell before the first moment, based on the random access configuration information, includes: sending a preamble before the first moment, based on the random access configuration information.

[0038] In conjunction with the third aspect, in some possible implementations of the third aspect, the above method further includes: receiving a first message, which is used to respond to the above preamble, the first message carrying a TA.

[0039] In conjunction with the third aspect, in some possible implementations of the third aspect, the aforementioned second information is used to indicate timer information used to determine the first moment.

[0040] In conjunction with the third aspect, in some possible implementations of the third aspect, the above method also includes: starting a timer after receiving the above switching command.

[0041] By starting and timing out timers, the terminal device and the access network device can align to the first moment, so that the terminal device can perform the handover process at the first moment, and the access network device can also sense the departure of the terminal device at the first moment, and thus perform corresponding actions (such as stopping the scheduling of the terminal device or releasing the context information of the terminal device).

[0042] Fourthly, this application provides another switching method, which can be executed by a second communication device. The second communication device can be an access network device, or a circuit or chip applicable to the access network device (such as a modem chip, also known as a baseband chip, or a SoC chip or SIP chip containing a modem core), and this application does not limit it in this regard.

[0043] For example, the method includes: sending a handover command to instruct a terminal device to hand over to a target cell, the handover command including random access configuration information and second information, the second information indicating a first moment, the random access configuration information being used to perform an uplink synchronization process with the target cell.

[0044] Optionally, the handover command may also include reference signal configuration information of the target cell, which is used to perform the downlink synchronization process with the target cell.

[0045] In the above scheme, the access network device sends out random access configuration information before the first moment, which makes it easier for the terminal device to perform the uplink synchronization process and / or downlink synchronization process with the target cell before the first moment indicated by the access network device (i.e. the moment of handover). This helps to reduce the interruption time in the subsequent handover process (such as the time required for the uplink / downlink synchronization process).

[0046] In conjunction with the fourth aspect, in some possible implementations of the fourth aspect, the method further includes: receiving first information before sending a handover command, the first information indicating at least one of the following: a predicted measurement result of a first cell, the first cell including the target cell; or a predicted measurement event related to the first cell, the first cell including the target cell.

[0047] In conjunction with the fourth aspect, in some possible implementations of the fourth aspect, the above method further includes: determining the switching command based on the first information.

[0048] In conjunction with the fourth aspect, in some possible implementations of the fourth aspect, the above handover command may also include: random access-free configuration information of the target cell, which includes CG configuration information and / or DG configuration information.

[0049] In conjunction with the fourth aspect, in some possible implementations of the fourth aspect, the aforementioned second information is used to indicate timer information used to determine the first moment.

[0050] It should be understood that the fourth aspect of this application corresponds to the technical solution of the third aspect of this application, and the possible implementations of the fourth aspect and the possible implementations of the third aspect have similar beneficial effects, which will not be repeated here.

[0051] Fifthly, this application provides yet another switching method, which can be executed by a first communication device. The first communication device can be a terminal device, or a circuit or chip applicable to a terminal device (such as a modem chip, also known as a baseband chip, or a SoC chip or SIP chip containing a modem core), and this application does not limit it in this regard.

[0052] For example, the method includes: sending first information, the first information indicating at least one of the following: a predicted measurement result of a first cell, the first cell including a target cell; or a predicted measurement event related to the first cell, the first cell including the target cell; receiving configuration information for configuring the target cell; accessing the target cell according to the configuration information; and transmitting data with the target cell and the source cell.

[0053] In the above scheme, the terminal device reports the predicted measurement results and / or related measurement events of the first cell, which enables the access network device to predict the handover time and / or the target cell for handover. This allows the access network device to send the aforementioned configuration information of the target cell before the predicted handover time. Furthermore, the terminal device can maintain its connection with the source cell and access the target cell, transmitting data with both the source and target cells, thus essentially achieving zero-interruption time for the terminal device.

[0054] In conjunction with the fifth aspect, in some possible implementations of the fifth aspect, the above-mentioned data transmission with the target cell and the source cell includes: sending a first data packet to the target cell; and sending a second data packet to the source cell, wherein the first data packet and the second data packet are identical.

[0055] In the above scheme, for the same data packet, the terminal device can send it to both the source cell and the target cell, which helps to ensure robustness, improve reliability, and reduce the reception latency of the data packet.

[0056] In conjunction with the fifth aspect, in some possible implementations of the fifth aspect, the above method further includes: receiving third information for instructing the release of the connection with the source access network device, which is a device providing services to the source cell.

[0057] In certain scenarios (such as when the signal quality of the source cell is below a threshold), the access network device can instruct the terminal device to release the connection with the source access network device, thereby reducing the power consumption of the terminal device.

[0058] Sixthly, this application provides yet another switching method, which can be executed by a second communication device. The second communication device can be an access network device, or a circuit or chip applicable to the access network device (such as a modem chip, also known as a baseband chip, or a SoC chip or SIP chip containing a modem core), and this application does not limit it in this regard.

[0059] For example, the method includes: receiving first information for indicating at least one of the following: a predicted measurement result of a first cell, the first cell including a target cell; or a predicted measurement event related to the first cell, the first cell including the target cell; and sending configuration information based on the first information for configuring the target cell.

[0060] In the above scheme, the terminal device reports the predicted measurement results and / or related measurement events of the first cell, which enables the access network device to predict the handover time and / or the target cell for handover. This allows the access network device to send the aforementioned configuration information of the target cell before the predicted handover time. Furthermore, the terminal device can maintain its connection with the source cell and access the target cell, transmitting data with both the source and target cells, thus essentially achieving zero-interruption time for the terminal device.

[0061] In conjunction with the sixth aspect, in some possible implementations of the sixth aspect, the above method further includes: receiving downlink data from a core network device and sending downlink data to a target access network device, wherein the target access network device provides services to the target cell.

[0062] In conjunction with the sixth aspect, in some possible implementations of the sixth aspect, the above method further includes: sending third information to the terminal device, the third information being used to indicate the release of the connection with the source access network device, the source access network device providing services to the source cell.

[0063] In conjunction with the sixth aspect, in some possible implementations of the sixth aspect, the above method further includes: sending a fourth message to the core network device, the fourth message being used to indicate the release of the connection with the source access network device, the source access network device providing services to the source cell.

[0064] It should be understood that the sixth aspect of this application corresponds to the technical solution of the fifth aspect of this application, and the beneficial effects achieved by the possible implementations of the sixth aspect and the possible implementations of the fifth aspect are similar, and will not be repeated here.

[0065] In a seventh aspect, this application provides a communication apparatus for performing the methods in the first to sixth aspects and any possible implementations of the first to sixth aspects described above. Specifically, the communication apparatus includes a module for performing the methods in any possible implementations of the first to sixth aspects described above.

[0066] Eighthly, this application provides another communication device, including a processor coupled to a memory, which can be used to execute instructions in the memory to implement the methods in the first to sixth aspects and any possible implementations of the first to sixth aspects. Optionally, the communication device further includes a memory. Optionally, the communication device further includes a communication interface, to which the processor is coupled.

[0067] In one implementation, the communication device is a terminal device or a network device. When the communication device is a terminal device or a network device, the communication interface can be a transceiver or an input / output interface.

[0068] In another implementation, the communication device is a chip applicable to terminal equipment or access network equipment. When the communication device is a chip applicable to terminal equipment or access network equipment, the aforementioned communication interface can be an input / output interface.

[0069] Ninthly, this application provides a processor, including: an input circuit, an output circuit, and a processing circuit. The processing circuit is configured to receive signals through the input circuit and transmit signals through the output circuit, causing the processor to execute the methods described in the first to sixth aspects and any possible implementation thereof.

[0070] In the specific implementation process, the processor can be a chip, the input circuit can be an input pin, the output circuit can be an output pin, and the processing circuit can be a transistor, gate circuit, flip-flop, and various logic circuits. The input signal received by the input circuit can be received and input by, for example, but not limited to, a receiver, and the signal output by the output circuit can be, for example, but not limited to, output to a transmitter and transmitted by the transmitter. Furthermore, the input circuit and the output circuit can be the same circuit, which is used as the input circuit and the output circuit at different times. This application does not limit the specific implementation method of the processor and various circuits.

[0071] In a tenth aspect, this application provides a communication device including a processor and a memory. The processor is used to read instructions stored in the memory, receive signals via a receiver, and transmit signals via a transmitter to execute the methods in the first to sixth aspects and any possible implementations of the first to sixth aspects described above.

[0072] Optionally, the processor may be one or more, and the memory may be one or more.

[0073] Optionally, the memory may be integrated with the processor, or the memory may be separated from the processor.

[0074] In the specific implementation process, the memory can be a non-transitory memory, such as read-only memory (ROM), which can be integrated with the processor on the same chip or set on different chips. This application does not limit the type of memory or the way the memory and processor are set.

[0075] It should be understood that related data interaction processes, such as sending configuration information, can be a process of outputting configuration information from the processor, and receiving configuration information can be a process of the processor receiving input configuration information. Specifically, the processed output data can be output to the transmitter, and the input data received by the processor can come from the receiver. Here, the transmitter and receiver can be collectively referred to as a transceiver.

[0076] The communication device in the tenth aspect above can be a chip. The processor can be implemented in hardware or software. When implemented in hardware, the processor can be a logic circuit, integrated circuit, etc. When implemented in software, the processor can be a general-purpose processor that reads software code stored in a memory. The memory can be integrated into the processor or located outside the processor and exist independently.

[0077] In one aspect, this application provides a computer program product comprising: a computer program (also referred to as code or instructions) that, when run, causes a computer to perform the methods described in the first to sixth aspects and any possible implementation thereof.

[0078] In a twelfth aspect, this application provides a computer-readable storage medium storing a computer program (also referred to as code or instructions) that, when run on a computer, causes the computer to perform the methods described in the first to sixth aspects and any possible implementation thereof.

[0079] It should be understood that aspects seven to twelfth of this application correspond to the technical solutions of aspects one to six of this application, and the beneficial effects achieved by each aspect and the corresponding possible implementation are similar, and will not be repeated here. Attached Figure Description

[0080] Figure 1 This is a schematic diagram of the architecture of a communication system applicable to the methods provided in the embodiments of this application;

[0081] Figure 2 This is a schematic diagram of the architecture of the core network and the radio access network provided in the embodiments of this application;

[0082] Figure 3 This is a flowchart illustrating a cell handover method;

[0083] Figure 4 This is a schematic diagram illustrating the composition of the interruption time provided in the embodiments of this application;

[0084] Figure 5 This is a schematic diagram of AI-based prediction provided in an embodiment of this application;

[0085] Figure 6 This is a schematic diagram of the AI-based switching mechanism provided in an embodiment of this application;

[0086] Figure 7 This is a flowchart illustrating the switching method provided in an embodiment of this application;

[0087] Figure 8 This is a detailed flowchart illustrating the switching method provided in the embodiments of this application;

[0088] Figure 9 This is a flowchart illustrating another switching method provided in an embodiment of this application;

[0089] Figure 10 This is a detailed flowchart illustrating another switching method provided in an embodiment of this application;

[0090] Figure 11 This is a flowchart illustrating yet another switching method provided in an embodiment of this application;

[0091] Figure 12 This is a detailed flowchart illustrating yet another switching method provided in an embodiment of this application;

[0092] Figure 13 This is a schematic block diagram of a communication device provided in an embodiment of this application;

[0093] Figure 14 This is a schematic block diagram of another communication device provided in the embodiments of this application;

[0094] Figure 15It is a schematic block diagram of the network element function division and protocol layer structure diagram of the O-RAN device provided by the embodiment of the present application. Detailed implementation manners

[0095] To facilitate the understanding of the embodiments of the present application, the following points are first explained:

[0096] First, in the embodiments of the present application, terms such as "first" and "second" are used to distinguish identical or similar items with basically the same functions and roles. For example, the first communication device and the second communication device are only used to distinguish different communication devices, and do not limit their sequence. Those skilled in the art can understand that terms such as "first" and "second" do not limit the quantity and execution order, and terms such as "first" and "second" do not necessarily limit being different.

[0097] It should be noted that in the embodiments of the present application, words such as "exemplarily" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplarily" or "for example" in the present application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Exactly speaking, using words such as "exemplarily" or "for example" aims to present related concepts in a specific manner.

[0098] In the embodiments of the present application, "at least one" means one or more, and "multiple" means two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone, where A and B can be singular or plural. The character " / " generally represents that the associated objects before and after are in an "or" relationship. "At least one (item)" or its similar expression refers to any combination of these items, including any combination of single item (item) or plural items (items). For example, at least one (item) of a, b, or c can represent: a, b, c, a - b, a - c, b - c, or a - b - c, where a, b, c can be single or multiple.

[0099] Second, "send" and "receive" in the embodiments of the present application represent the direction of signal transmission. For example, "send information to the second device" can be understood as the destination of the information is the second device, which can include directly sending through the air interface, and also include indirectly sending through the air interface by other units or modules. "Receive information from the second device" can be understood as the source of the information is the second device, which can include directly receiving from the second device through the air interface, and can also include indirectly receiving from the second device through the air interface from other units or modules. "Send" can also be understood as the "output" of the chip interface, and "receive" can also be understood as the "input" of the chip interface.

[0100] In other words, sending and receiving can be done between devices, such as between a second device and a first device; or it can be done within a device, such as between components, modules, chips, software modules, or hardware modules within a device via a bus, wiring, or interface.

[0101] It is understandable that information may undergo necessary processing, such as encoding and modulation, before being sent from the source to the destination. Similarly, the destination, upon receiving information from the source, can also perform corresponding processing, such as decoding and demodulation, to interpret the valid information from the source. Similar expressions in this application can be understood in a similar way and will not be elaborated further.

[0102] Third, in the embodiments of this application, "instruction" can include direct instruction and indirect instruction, as well as explicit instruction and implicit instruction. The information indicated by a certain piece of information (as described below, the instruction information) is called the information to be instructed. In the specific implementation process, there are many ways to instruct the information to be instructed, such as, but not limited to, directly instructing the information to be instructed, such as the information to be instructed itself or its index. It can also indirectly instruct the information to be instructed by instructing other information, where there is a correlation between the other information and the information to be instructed; or it can only instruct a part of the information to be instructed, while the other parts of the information to be instructed are known or pre-agreed upon. For example, the instruction of specific information can be achieved by using a pre-agreed (e.g., protocol predefined) arrangement order of various pieces of information, thereby reducing instruction overhead to a certain extent. This application does not limit the specific method of instruction.

[0103] It is understandable that, for the sender of the instruction information, the instruction information can be used to indicate the information to be indicated, and for the receiver of the instruction information, the instruction information can be used to determine the information to be indicated.

[0104] Fourth, in the embodiments of this application, descriptions such as "when," "under the circumstances," "if," and "if" all refer to the fact that the device (e.g., access network device or terminal device) will make corresponding processing under certain objective circumstances. They are not time limits, nor do they require the device (e.g., access network device or terminal device) to make a judgment action when implementing it, nor do they imply any other limitations.

[0105] Fifth, the predefined terms in this application can be understood as: definition, pre-defined, storage, pre-storage, pre-negotiation, pre-configuration, solidification, or pre-firing.

[0106] Sixth, in the embodiments of this application, both the source cell and the serving cell refer to the cell that provides services to the terminal device. This can also be understood as the cell that provides services to the terminal device before the terminal device switches cells. The source cell and the serving cell can be interchanged, and the possibility of using other names in future protocols is not excluded. Correspondingly, the device corresponding to the source cell can be called the source access network device, the serving access network device, etc., and this application does not limit this. Similarly, the target cell refers to the cell that the terminal device wants to switch to, or it can also be understood as the cell that provides services to the terminal device after the terminal device switches cells. The device corresponding to the target cell can be called the target access network device, and this application does not exclude the possibility of using other names for the target cell and the target access network device.

[0107] Seventh, the technical solutions of the embodiments of this application can be applied to various communication systems, such as: Long Term Evolution (LTE) system, LTE Frequency Division Duplex (FDD) system, LTE Time Division Duplex (TDD) system, 5th Generation (5G) system or New Radio (NR) system, future communication systems, etc.

[0108] The terminal equipment in this application embodiment can also be referred to as: user equipment (UE), mobile station (MS), mobile terminal (MT), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication equipment, user agent, or user device, etc.

[0109] Terminal devices can be devices that provide voice / data connectivity to users, such as handheld devices with wireless connectivity, in-vehicle devices, etc. Currently, examples of terminal devices include: mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), point-of-sale (POS) machines, customer-premises equipment (CPEs), light user equipment (UEs), reduced capability UEs (REDCAP UEs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving vehicles, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, and personal digital assistants (PDAs). This application does not limit the scope to include devices such as personal assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, in-vehicle devices, wearable devices, terminal devices in 5G networks, or terminal devices in future evolved public land mobile networks (PLMNs).

[0110] By way of example and not limitation, in this application, the terminal device can be a terminal device in an Internet of Things (IoT) system. The Internet of Things is an important component of future information technology development. Its main technical characteristic is connecting objects to networks through communication technologies, thereby realizing an intelligent network of human-machine interconnection and object-to-object interconnection. Exemplarily, the terminal device in the embodiments of this application can be a wearable device. Wearable devices, also known as wearable smart devices, are a general term for devices that apply wearable technology to intelligently design and develop everyday wearables, such as glasses, gloves, watches, clothing, and shoes. Wearable devices are portable devices that can be worn directly on the body or integrated into a user's clothing or accessories. Wearable devices are not merely hardware devices; they can also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly defined, wearable smart devices include those with comprehensive functions, large size, and the ability to achieve complete or partial functions without relying on a smartphone, such as smartwatches or smart glasses, as well as those focused on a specific application function and requiring the use of other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

[0111] By way of example and not limitation, in the embodiments of this application, the terminal device can also be a terminal device in machine-type communication (MTC). Furthermore, the terminal device can also be an on-board module, on-board component, on-board chip, or on-board unit, etc., built into a vehicle as one or more components or units. The vehicle can implement the methods provided in this application through the built-in on-board module, on-board component, on-board chip, or on-board unit, etc. Therefore, the embodiments of this application can also be applied to vehicle networking, such as vehicle-to-everything (V2X), long-term evolution-vehicle (LTE-V) technology, and vehicle-to-vehicle (V2V) technology.

[0112] Access network equipment, also known as radio access network (RAN) equipment, is a device that communicates with terminal devices and has wireless transceiver capabilities. RAN equipment provides wireless communication services, allowing terminals to access the wireless network. RAN equipment can be a node in the radio access network, often referred to as a RAN node.

[0113] In one possible scenario, a RAN node can be a base station (BS), an evolved NodeB (eNodeB), a transmission reception point (TRP), a home evolved NodeB (or home Node B, HNB), an access point (AP) for wireless fidelity (Wi-Fi), a mobile switching center, a next-generation NodeB (gNB) in a 5G mobile communication system, a next-generation base station in a future mobile communication system, or a base station in a future mobile communication system. A RAN node can also be a device that performs base station functions in device-to-device (D2D) communication systems, V2X communication systems, machine-to-machine (M2M) communication systems, and IoT communication systems. A RAN node can also be a RAN node in a non-terrestrial network (NTN), meaning that a RAN node can be deployed on a high-altitude platform or a satellite. RAN nodes can be macro base stations, micro base stations, indoor stations, relay nodes, donor nodes, etc., or radio controllers in cloud radio access network (CRAN) scenarios, or nodes in open radio access network (O-RAN or ORAN) scenarios. Optionally, RAN nodes can also be servers, wearable devices, vehicles, or in-vehicle equipment. For example, in V2X technology, RAN nodes can be roadside units (RSUs). Of course, RAN nodes can also be nodes in the core network.

[0114] In another possible scenario, multiple RAN nodes collaborate to assist the terminal in achieving wireless access, with different RAN nodes each implementing a portion of the base station's functions. For example, RAN nodes can be central units (CUs), distributed units (DUs), CU-control plane (CPs), CU-user plane (UPs), or radio units (RUs), etc. CUs and DUs can be set up separately or included in the same network element, such as a baseband unit (BBU). RUs can be included in radio frequency equipment or radio frequency units, such as remote radio units (RRUs), active antenna units (AAUs), or remote radio heads (RRHs).

[0115] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an open RAN (ORAN / O-RAN) system, CU can also be called open CU (O-CU), DU can also be called open DU (O-DU), CU-CP can also be called open CU-CP (O-CU-CP), CU-UP can also be called open CU-UP (O-CU-UP), and RU can also be called open RU (O-RU).

[0116] Any one of the CU (or CU-CP, CU-UP), DU, and RU units can be implemented through software modules, hardware modules, or a combination of software and hardware modules. That is, the wireless access network device in this application can be a virtualized device, for example, implemented through general-purpose hardware and instantiated virtualization functions, or dedicated hardware and instantiated virtualization functions. The general-purpose hardware can be a server, such as a cloud server.

[0117] To facilitate understanding of the embodiments of this application, firstly, in conjunction with Figure 1 The communication system applicable to the embodiments of this application will be described in detail.

[0118] Figure 1 This is a schematic diagram of the architecture of a communication system 10 applicable to the methods provided in the embodiments of this application. For example... Figure 1 As shown, the communication system 10 includes a wireless access network 100 and a core network 200. Optionally, the communication system 10 may also include an Internet 30.

[0119] The wireless access network 100 may include at least one access network device (such as...) Figure 1 110a and 110b in the above), may also include at least one terminal device (such as Figure 1 (120a-120j in the middle).

[0120] Terminal devices can connect to access network devices wirelessly, while access network devices can connect to the core network wirelessly or via wired connections. Core network devices and access network devices can be independent, separate physical devices, or they can integrate the functions of core network devices and the logical functions of access network devices onto the same physical device. Alternatively, a single physical device can integrate some core network device functions and some access network device functions. Terminal devices and access network devices can connect to each other via wired or wireless connections.

[0121] It should be understood that the connection between devices can also be understood as the ability of devices to communicate with each other. For example, the connection between access network devices means that access network devices can communicate with each other.

[0122] Wireless access network devices and terminal devices, as well as access network devices and terminal devices, can communicate using licensed spectrum, unlicensed spectrum, or both simultaneously. Communication can occur using spectrum below 6 GHz, spectrum above 6 GHz, or both simultaneously. The embodiments of this application do not limit the spectrum resources used for wireless communication.

[0123] Among them, the wireless access network equipment can be a base station deployed in the air, such as a satellite base station 110a; or it can be a base station deployed indoors, such as a micro base station or an indoor station 110b.

[0124] The terminal device can be a terminal device deployed in the air, such as... Figure 1 The 120i can be a helicopter or drone; it can also be a terminal device deployed on the ground, such as... Figure 1 The mobile phones 120a, 120e, 120f, 120j, the vehicle 120b, and the printer 120h are among them.

[0125] Access network equipment and terminal equipment can be fixed in location or mobile. For example, access network equipment and terminal equipment can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can also be deployed in the air on airplanes, balloons, and artificial satellites.

[0126] The roles of access network equipment and terminal equipment can be relative. For example, Figure 1 In this context, the helicopter or drone 100i can be configured as a mobile base station. For those 120j accessing the wireless access network 100 via 120i, 120i is a base station; however, for 110a, 120i is a terminal device, meaning that 110a and 120i communicate via a wireless air interface protocol. Alternatively, 110a and 120i can also communicate via an interface protocol between access network devices; in this case, 120i is also a base station relative to 110a. Therefore, both wireless access network devices and terminal devices can be collectively referred to as communication devices. Figure 1 The 110a, 110b, and 120a-120j in the text can be referred to as communication devices with their respective corresponding functions, such as communication devices with base station functions or communication devices with terminal functions.

[0127] It should be understood that Figure 1 This is just an illustration; the communication system may also include other devices, such as wireless repeaters and wireless backhaul devices. Figure 1 Not shown in the figure. This application does not limit this aspect in its embodiments.

[0128] The aforementioned communication devices, such as Figure 1 Access network devices or terminal devices can be configured with multiple antennas. These multiple antennas may include at least one transmitting antenna for transmitting signals and at least one receiving antenna for receiving signals. Additionally, each communication device also includes a transmitter chain and a receiver chain, which, as will be understood by those skilled in the art, may include multiple components related to signal transmission and reception (e.g., processors, modulators, multiplexers, demodulators, demultiplexers, or antennas). Therefore, access network devices and terminal devices can communicate via multi-antenna technology.

[0129] Optionally, the communication system 10 may also include other network entities such as a network controller and a mobility management entity, but the embodiments of this application are not limited thereto.

[0130] It should also be understood that the method provided in the embodiments of this application can be applied to a variety of communication systems, including 5G New Radio systems. Communication system 10 is only an example. This application does not limit the specific architecture of the applicable system, nor does it limit the number and form of various devices contained in each communication system.

[0131] Figure 2 This is a schematic diagram of the architecture of the core network and the wireless access network provided in the embodiments of this application. Figure 2 The diagram illustrates the connection between the core network and the radio access network.

[0132] like Figure 2As shown, the system includes a 5G core network (5GC) and a radio access network (such as NG-RAN). The 5GC includes core network equipment 210 and 220, which may be, for example, access and mobility management (AMF) network elements / user plane function (UPF) network elements. The NG-RAN includes access network equipment 230 to 260, which may be gNBs and / or eNBs. For example, access network equipment 230 and 240 are gNBs, and access network equipment 250 and 260 are eNBs. Multiple access network equipment can be interconnected via the Xn interface. These multiple access network equipment can be connected to the 5GC via the NG interface, more specifically, connected to AMF network elements via the N2 interface, and connected to UPF network elements via the N3 interface.

[0133] It should be understood that Figure 2 The example shown is merely illustrative, depicting two core network devices and four access network devices, but this should not constitute any limitation on this application. Each device can be one or more. There can be one or more access network devices connected to the same core network.

[0134] It should also be understood that, although Figure 2 Not shown, but each access network device can connect to one or more terminal devices, and the terminal devices can establish communication connections with the access network devices.

[0135] Currently, to meet business requirements, terminal devices can access the network. For example, during the process of a terminal device accessing the network, the following steps can be taken in sequence: cell search and selection, random access, radio resource control (RRC) connection establishment, initial context establishment, and session establishment.

[0136] Through the cell search and selection process, the terminal device can choose a suitable cell to connect to, such as a cell with better signal quality. Better signal quality can mean that the signal quality is above a certain threshold; or it can mean that the signal quality is relatively good, such as choosing the cell with the best signal quality among several cells.

[0137] Random access can be a four-step random access procedure or a two-step random access procedure. Through the random access procedure, the terminal device can establish an initial connection with the access network device.

[0138] The RRC connection establishment process can occur after the random access procedure. During the RRC connection establishment process, the terminal device can send an RRC connection establishment request to the access network device; correspondingly, the access network device receives the RRC connection establishment request from the terminal device. Furthermore, the access network device can allocate radio resources to the terminal device based on the RRC connection establishment request, enabling higher-level communication between the terminal device and the access network device, allowing the terminal device to perform data transmission and signal reception.

[0139] In addition, in order to communicate with the core network side and realize various services, the initial context establishment and session establishment process can also be performed.

[0140] Initial context establishment can be understood as the process of establishing an initial communication context between a terminal device and core network equipment. Initial context establishment typically occurs when a terminal device first accesses or re-accesses the network. Through initial context establishment, a management entity can be created for the terminal device within the network for subsequent communication and resource management. Initial context establishment can be achieved, for example, but not limited to, through one or more of the following processes: the terminal device exchanging non-access stratum (NAS) messages (for authentication, registration, and context establishment), security context establishment, and context acknowledgment with the core network equipment.

[0141] Session establishment, such as protocol data unit (PDU) session establishment, refers to the process of establishing a data transmission channel between a terminal device and a data network (such as the Internet). In 5G networks, PDU sessions can be used to manage and transmit user data.

[0142] Through initial context establishment and PDU session establishment, terminal devices can register and authenticate in the network and establish a reliable communication channel with the data network, enabling terminal devices to transmit data efficiently and securely, thus meeting the communication needs of terminal devices.

[0143] During communication between terminal devices, the UE context involved may include, but is not limited to, the following information:

[0144] 1. UE capabilities. For example, the functions supported by the terminal device, encryption algorithms, and slicing capabilities.

[0145] 2. Authentication Information. Authentication information can be used to verify the identity and permissions of terminal devices.

[0146] 3. Information used to indicate access network devices. For example, the ID of an access network device can be used to indicate the access network device that establishes a connection with the terminal device.

[0147] 4. Quality of Service Class Identifier (QCI). This can be used to determine the service quality and priority of different services.

[0148] 5. Security parameters. Such as encryption keys and integrity protection algorithms.

[0149] 6. Network configuration. This includes, for example, access layer configuration and bearer context.

[0150] After a terminal device connects to the network, mobility management can be implemented to provide it with good network conditions. For example, when an event such as A3 or A5 is triggered, a cell handover procedure can be initiated so that the terminal device can switch to a cell with better network conditions.

[0151] An A3 event can be triggered when the signal quality of a neighboring cell exceeds the signal quality of the serving cell plus an offset. This offset can be positive or negative. When an A3 event is triggered, the terminal device can report a measurement report to the access network equipment. This measurement report can include the terminal device's measurement results of the neighboring cell and / or the serving cell.

[0152] An A5 event can be triggered when the signal quality of the serving cell is below a certain threshold and the signal quality of a neighboring cell is above a certain threshold. When an A5 event is triggered, the terminal device can report a measurement report to the access network equipment. This measurement report may include the terminal device's measurement results of the neighboring cell and / or the serving cell.

[0153] Alternatively, the signal quality of a cell can be characterized by any of the following: reference signal received power (RSRP), reference signal received quality (RSRQ), signal to interference plus noise ratio (SINR), or received signal strength indication (RSSI).

[0154] The following is combined with Figure 3 The cell handover process is explained in detail.

[0155] Figure 3This is a flowchart illustrating a cell handover method 300. Method 300 shows the process of a terminal device handing over from a source access network device to a target access network device. Method 300 can be applied, for example, to a communication system 10. Method 300 includes the following steps:

[0156] S301. The source access network device sends measurement configuration information to the terminal device to control the measurement behavior of the terminal device. This measurement configuration information may be included in an RRC reconfiguration message. Correspondingly, the terminal device receives the measurement configuration information from the source access network device and performs measurements according to the measurement configuration information.

[0157] Measurement configuration information can also be understood as measurement control information, which may include, for example, measurement object configuration, measurement report configuration, and measurement gap configuration.

[0158] The measurement object can be, for example, a same-frequency measurement, that is, a signal measurement of other cells that have the same frequency as the current serving cell; or, a different-frequency measurement, that is, a signal measurement of other cells that have a different frequency than the current serving cell.

[0159] Measurement report configuration can specify the content to be included in the measurement report reported by the terminal device, the measurement reporting cycle, or the measurement event configuration, etc.

[0160] S302. The terminal device sends an RRC reconfiguration complete message to the source access network device. Correspondingly, the source access network device receives the RRC reconfiguration complete message from the terminal device.

[0161] The RRC reconfiguration completion message can be understood as a response to the RRC reconfiguration message, such as indicating that the RRC reconfiguration message was successfully received.

[0162] S303. The terminal device performs measurements based on the measurement configuration information configured by the source access network device. The terminal device then performs measurement reporting based on the obtained measurement results, such as sending a measurement report. Correspondingly, the source access network device receives the measurement report from the terminal device.

[0163] Optionally, the terminal device may send measurement reports periodically; or the terminal device may send a measurement report to the source access network device after determining that the event triggering conditions are met based on the measurement results.

[0164] The event can be, for example, an A3 event or an A5 event, or other events; this application does not limit the specific events.

[0165] S304. Source access network devices make switching decisions based on measurement reports.

[0166] In other words, the source access network device can determine whether to perform a handover, or determine the handover strategy and target cell (or frequency point), based on the measurement results indicated in the measurement report. The target cell can be understood as the cell that the terminal device determines to handover to, as determined by the source access network device.

[0167] For example, the source access network device can determine, based on the measurement results of the target cell indicated in the measurement report, that the target cell has high signal quality, such as exceeding a certain threshold or that the target cell has the best signal quality in the measurement report. And / or, the source access network device can also determine, based on the measurement results of the serving cell indicated in the measurement report, that the serving cell has poor signal quality, such as below a certain threshold. Therefore, in order to provide better network conditions for the terminal device, the source access network device can determine (or decide) to have the terminal device switch to the target cell.

[0168] S305. The source access network device sends a handover request to the target access network device where the target cell is located; correspondingly, the target access network device receives the handover request from the source access network device. This handover request can be understood as a message requesting that the terminal device hand over from the serving cell (source access network device) to the target cell (target access network device).

[0169] The aforementioned handover request may include, but is not limited to, one or more of the following: the identifier of the target cell, the key, the identifier of the terminal device in the source cell, or the access layer configuration.

[0170] S306. The target access network equipment performs admission control.

[0171] Admission control is the process by which a target access network device determines, based on its current resource status, whether it can establish a connection with a new terminal device. The target access network device can determine its available radio resources, transmission resources, and other network resources to ascertain whether the resources it can provide can support the new connection request without affecting the quality of service for existing users.

[0172] If the target access network device determines that it does not have sufficient resources to support a new terminal device connection, the target access network device may send a handover rejection message to the source access network device to indicate to the source access network device that it is not allowed to hand over the terminal device to the target access network device.

[0173] If the target access network device determines that it has sufficient resources to support a new terminal device connection, it can create a new UE context instance for the terminal device and allocate transmission resources for it. The target access network device can then execute S307.

[0174] S307. The target access network device sends a handover request acknowledgment to the source access network device. Correspondingly, the source access network device receives the handover request acknowledgment from the target access network device. The handover request acknowledgment can be understood as a response to the handover request, and it can be used to indicate permission for the terminal device to hand over to the target access network device. The handover command sent to the terminal device is included in the handover request acknowledgment in the form of an RRC container.

[0175] S308. The source access network device sends an RRC reconfiguration message to the terminal device. This RRC reconfiguration message instructs the terminal device to hand over to the target cell. Correspondingly, the terminal device receives the RRC reconfiguration message from the source access network device.

[0176] The aforementioned RRC reconfiguration message, also known as a handover command, is used to instruct the terminal device to hand over to the target cell. The handover command is generated by the target access network device and transparently transmitted through the source access network device. The source access network device performs necessary encryption and integrity protection on this command. The handover command contains configuration information of the target cell, including but not limited to one or more of the following: the identifier of the target cell, the identifier of the terminal device in the target cell, the security algorithm identifier of the target access network device, or the random access channel (RACH) configuration information of the target cell. The RACH configuration information is used to configure random access resources.

[0177] S309. The source access network device sends a sequence number (SN) status transfer to the target access network device. Correspondingly, the target access network device receives the SN status information from the source access network device.

[0178] SN status transmissions can carry uplink Packet Data Convergence Protocol (PDCP) SN receive status and downlink PDCP SN transmit status. The uplink PDCP SN receive status indicates the PDCP SN of the first lost uplink PDCP service data unit (SDU), and can also indicate the PDCP SN of an out-of-order uplink PDCP SDU that needs to be retransmitted by the terminal equipment to the target cell. The downlink PDCP SN transmit status indicates the next PDCP SN that the target cell should assign to a new PDCP SDU (which does not yet have a PDCP SN).

[0179] Optionally, the source access network device can also perform data forwarding to the destination access network device. The data packets forwarded by the source access network device to the destination access network device may include data packets that have been assigned a PDCP SN by the source access network device, and may also include data packets that have not yet been assigned a PDCP SN.

[0180] S310, The terminal device performs the synchronization process with the target access network device.

[0181] After receiving the handover command, the terminal device executes a synchronization process with the target access network device, which is used for communication with the target access network device after a successful handover. Alternatively, the terminal device can execute a synchronization process with the target cell. This synchronization process can include downlink synchronization and uplink synchronization.

[0182] S311. The target access network device sends a random access response (RAR) to the terminal device. Correspondingly, the terminal device receives the aforementioned RAR.

[0183] The RAR file mentioned above can contain configuration information for TA and uplink resources.

[0184] S312. The terminal device sends an RRC reconfiguration complete message to the target access network device. This RRC reconfiguration complete message indicates that the handover is complete, meaning the terminal device has switched to the target cell. Correspondingly, the target access network device receives the RRC reconfiguration complete message from the terminal device. At this point, data transmission can occur between the target access network device and the terminal device.

[0185] S313. The target access network device sends a path switch request message to the AMF network element. The path switch request message indicates that the terminal device has switched to the target cell. The path switch request message may include the target cell identifier and the list of PDU sessions transferred (indicating the PDU sessions established by the target access network device for the terminal device), etc. Correspondingly, the AMF network element can receive the path switch request message from the target access network device.

[0186] This triggers the core network to switch the downlink data path to the target access network device and establish an NG-control plane (C) interface with the target access network device. At this point, the air interface handover is complete.

[0187] S314. The AMF network element sends a user plane (UP) update request to the UPF network element. Correspondingly, the UPF network element receives the UP update request.

[0188] S315 and UPF network elements convert downlink data paths.

[0189] UPF network elements switch the downlink data path to the target access network device.

[0190] S316. The core network device sends a path switch request acknowledgement message to the target access network device. Correspondingly, the target access network device receives the path switch request acknowledgement message from the core network device. The path switch request acknowledgement message can be understood as a response to the path switch request and can be used to indicate that the path switch was successful.

[0191] S317. The target access network device sends a UE context release message to the source access network device. Correspondingly, the source access network device receives the UE context release message from the target access network device and can release resources and UE context related to the switched terminal device based on the message.

[0192] S318, Source access network equipment releases resources.

[0193] Upon receiving a UE context release message, the source access network device can release the radio bearer and resources associated with the UE context. If data forwarding is not yet complete, the source access network device may continue data forwarding without releasing the relevant resources until the data forwarding is complete, at which point the relevant resources will be released.

[0194] It is understandable that not all steps in the above process need to be performed; that is, only some steps may need to be performed.

[0195] exist Figure 3In the illustrated process, when the terminal device receives a handover command, it can disconnect from the source access network device and execute downlink and uplink synchronization procedures with the target cell. Once the terminal device successfully establishes a connection with the target access network device (e.g., when the terminal device completes the random access procedure, or when the target access network device receives the RRC reconfiguration completion message), data transmission can occur between the terminal device and the target access network device. The time from when the terminal device disconnects from the source access network device to when it establishes a connection with the target access network device can be called the interruption time (or handover delay). The following will combine... Figure 4 The composition of the aforementioned interruption time will be explained in detail.

[0196] Figure 4 This is a schematic diagram illustrating the composition of the interruption time provided in the embodiments of this application.

[0197] like Figure 4 As shown, the interruption time can include the following components:

[0198] 1. Terminal device reconfiguration phase:

[0199] RRC reconfiguration message processing: The time required for the terminal device to process the handover command (RRC reconfiguration message);

[0200] UE processing: The terminal device uses the target cell's configuration, and the timing of physical layer / data link layer changes.

[0201] 2. Downlink synchronization process

[0202] The terminal device detects the first available synchronization signal block (SSB) and thus obtains the time required for downlink timing;

[0203] The time required for the terminal device to process the SSB.

[0204] 3. Uplink synchronization process

[0205] The time required for the terminal device to acquire the first uplink transmission (i.e., the RACH timing);

[0206] The time the terminal device waits for RAR.

[0207] 4. Time required from receiving the RAR on the terminal device to completing the handover.

[0208] For example, the time required from when the terminal device receives the RAR to when the terminal device successfully sends the RRC reconfiguration complete message.

[0209] Traditional handover mechanisms rely on measurement results obtained from actual measurements taken by the terminal device to make handover decisions. Figure 3 In the S303 shown, the measurement report reported by the terminal device to the source access network device is based on actual measurements. In some scenarios, such as when the terminal device moves at a high speed, the cell deployment is dense, or the terminal device's services are sensitive to latency, the above handover mechanism may result in poor handover performance, such as handover too early / too late, or the ping-pong effect.

[0210] Therefore, an AI-based handover mechanism can be used. The main principle of an AI-based handover mechanism is to predict other measurement results (such as time-domain prediction and frequency-domain prediction) based on one or more of the following: historical measurement results, the movement trajectory of the terminal device, movement speed, big data, or communication maps. The network can then make handover decisions based on the predicted measurement results.

[0211] Figure 5 This is a schematic diagram of AI-based prediction provided in an embodiment of this application.

[0212] like Figure 5 As shown in a), time-domain prediction refers to predicting the measurement results of cell A at future times based on the measurement results obtained from the measurement of cell A.

[0213] like Figure 5 As shown in b), frequency domain prediction refers to predicting the measurement results of cell B at another frequency point 2 based on the measurement results of cell A at frequency point 1.

[0214] In the aforementioned AI-based handover mechanism, the source access network device can make handover decisions based on predicted measurement results, such as when to handover and which target cell to handover to. However, the terminal device still only begins the handover process after the handover time arrives.

[0215] Figure 6 This is a schematic diagram of the AI-based switching mechanism provided in the embodiments of this application.

[0216] like Figure 6 As shown, assuming the source access network device predicts, based on the predicted measurement results at time t1, that the neighboring cell will satisfy event A3 at time t2, or in other words, it predicts at time t1 that the terminal device needs to hand over the cell at time t2, then the access network device will issue a handover command after time t2. After receiving the handover command, the terminal device disconnects from the source access network device and executes the handover process, such as performing a random access procedure to the target cell. Therefore, the length of the interruption time (hereinafter referred to as interruption duration) during the handover process of the terminal device is not reduced. The components of the interruption time are as follows... Figure 4 As shown.

[0217] In view of this, this application provides a handover method in which the access network device can send the random access configuration information of the target cell before sending the handover command. In this way, the terminal device can perform the uplink synchronization process with the target cell in advance based on this information, such as performing the uplink synchronization process with the target cell before receiving the handover command or before performing the access process to the target cell. This helps to reduce the interruption time of the terminal device during the handover process.

[0218] For example, such as Figure 6 As shown, the source access network device can send the random access configuration information of the target cell before time t2, and send a handover command at time t2 to instruct the terminal device to hand over to the target cell. Correspondingly, the terminal device receives the random access configuration information of the target cell before time t2, so as to perform the uplink synchronization process with the target cell in advance, such as performing the uplink synchronization process with the target cell before receiving the handover command at time t2. In this way, after receiving the handover command, the terminal device can complete the access to the target cell without a random access process, without having to perform the uplink synchronization process after receiving the handover command, thereby reducing the interruption time of the terminal device during the handover process. For example, in the above scheme, the time required for the uplink synchronization process is omitted from the composition of the interruption time.

[0219] The handover method of this application will be described in detail below. The embodiments shown in this application illustrate the handover method provided by this application from the perspective of device interaction. The specific form and number of each device shown are merely examples and should not constitute any limitation on the implementation of the method provided by this application. Below, taking terminal devices and source access network devices as the execution subjects, the handover method of the embodiments of this application will be described in detail.

[0220] It should be understood that the source access network device can be the source access network device itself, or it can be replaced by a chip, chip system or processor that supports the handover method, or it can be replaced by a logic module or software that can implement all or part of the functions of the source access network device; the terminal device can be the terminal device itself, or it can be replaced by a chip, chip system or processor that supports the handover method, or it can be replaced by a logic module or software that implements all or part of the functions of the terminal device. This application does not make any specific limitations in this regard.

[0221] Figure 7 This is a flowchart illustrating the switching method 700 provided in an embodiment of this application. Method 700 is applicable to... Figure 1 The communication system 10 shown or Figure 2 The communication system shown, method 700 includes the following steps:

[0222] S701. The source access network device sends configuration information to the terminal device. This configuration information is used to configure the target cell and includes random access configuration information. Correspondingly, the terminal device receives the above configuration information.

[0223] The aforementioned random access configuration information is used to perform the uplink synchronization process with the target cell, or in other words, to perform the random access process to the target cell. This random access configuration information includes, but is not limited to, RACH common configuration, contention-free random access (CFRA) configuration, or gap configuration. Specifically, the RACH common configuration configures one or more of the following: preamble, random access timing, time-domain resources (such as time slots and subframes) for which the terminal device can attempt random access, and frequency-domain resources for which the terminal device can attempt random access. The CFRA configuration configures a dedicated preamble and / or time-frequency resources for the terminal device. The gap configuration configures the time period for the terminal device to perform the synchronization process.

[0224] Optionally, the configuration information may also include downlink synchronization configuration information for the downlink synchronization process between the terminal device and the target cell. For example, the downlink synchronization configuration information may include reference signal configuration information of the target cell, such as the period of the SSB or channel state information reference signal (CSI-RS).

[0225] It is understandable that the above configuration information may be generated by the target access network device and forwarded to the terminal device by the source access network device.

[0226] In possible implementation A, prior to S701, the source access network device may send a handover request to the target access network device, requesting a handover of the terminal device from the serving cell (source access network device) to the target cell (target access network device). Correspondingly, the target access network device receives the handover request from the source access network device. If the target access network device agrees to the handover request, it may send a handover request confirmation to the source access network device, which may carry the random access configuration information of the target cell. Correspondingly, the source access network device receives the handover request confirmation and forwards the random access configuration information to the terminal device.

[0227] Optionally, in the above possible implementation A, the handover request may carry / bear the predicted measurement results of the first cell and / or the predicted measurement events related to the first cell, so as to facilitate the target access network equipment in making handover decisions and resource scheduling decisions. The first cell mentioned above includes the target cell. It is understood that the first cell may include one or more neighboring cells. In one possible design, the first cell may also include the serving cell (source cell).

[0228] The aforementioned source access network device sends configuration information to the terminal device. In one possible implementation, the source access network device sends the configuration information before instructing the terminal device to handover to the target cell. Correspondingly, the terminal device receives the configuration information from the source access network device before receiving the instruction to handover to the target cell.

[0229] As an example, if the source access network device needs to instruct the terminal device to hand over to the target cell at a specific moment, the source access network device can send the aforementioned configuration information before that moment. Correspondingly, the terminal device receives the configuration information from the source access network device before that moment. The first moment can be a predicted handover time, or it can be a predicted time for instructing the terminal device to hand over to the target cell, or it can be the time when the handover command is issued based on predicted measurement results.

[0230] S702. The source access network device sends a handover command to the terminal device, which indicates the handover to the target cell. Correspondingly, the terminal device receives the handover command.

[0231] The handover command described above can be carried in an RRC reconfiguration message. The handover command may include, but is not limited to, one or more of the following: the identifier of the target cell, the identifier of the terminal device in the target cell, or the security algorithm identifier of the target access network device.

[0232] In one possible implementation, after the source access network device sends the aforementioned configuration information to the terminal device, it can send a handover command to the terminal device to instruct the terminal device to hand over to the target cell. Correspondingly, the terminal device receives the handover command. After receiving the handover command, the terminal device disconnects from the source access network device (source cell / serving cell).

[0233] Understandably, when the predicted measurement results change, the source access network device may choose not to send a handover command, or may change the target cell in the handover command. The source access network device may send a release indication to the target access network device, such as instructing it to release reserved random access configuration information and / or non-random access configuration information.

[0234] S703. The terminal device executes the access procedure to the target cell according to the above handover command. This access procedure is completed through a random access-free procedure.

[0235] The aforementioned "random access-free process" refers to a terminal device establishing a connection with the access network device without undergoing a random access procedure. During this process, the terminal device can send uplink signaling to the access network device based on pre-configuration information (hereinafter referred to as "random access-free configuration information"). This uplink signaling could be an RRC reconfiguration completion message or a media access control (MAC) control element (CE). This uplink signaling indicates to the access network device that the access procedure is complete. Correspondingly, the access network device receives this uplink signaling. Optionally, the access network device can also send a response message to the terminal device, such as a MAC CE acknowledgment.

[0236] In one possible implementation, the configuration information sent by the source access network device in S701 to the terminal device also includes non-random access configuration information. After receiving the handover command, the terminal device can perform a non-random access procedure to the target cell based on the non-random access configuration information.

[0237] In another possible implementation, the handover command sent by the source access network device to the terminal device includes non-random access configuration information. After receiving the handover command, the terminal device can perform a non-random access procedure to the target cell based on the non-random access configuration information.

[0238] The aforementioned random access-free configuration information includes CG configuration information and / or DG configuration information. CG refers to the uplink resources pre-configured by the access network equipment for the terminal equipment. DG refers to the uplink resources dynamically allocated by the access network equipment for the terminal equipment.

[0239] It is understood that the aforementioned random access-free configuration information can be generated by the target access network device and forwarded to the terminal device by the source access network device. For example, prior to S701, the source access network device could send a handover request to the target access network device, requesting a handover of the terminal device from the serving cell (source access network device) to the target cell (target access network device). Correspondingly, the target access network device receives the handover request from the source access network device. If the target access network device agrees to the handover request, it can send a handover request confirmation to the source access network device, which may carry the random access-free configuration information of the target cell. Correspondingly, the source access network device receives the handover request confirmation and forwards the random access-free configuration information to the terminal device.

[0240] Optionally, the terminal device may also perform a downlink synchronization process with the target cell before performing the uplink synchronization process with the target cell.

[0241] In one possible implementation, after receiving configuration information (including downlink synchronization configuration information), the terminal device executes the downlink synchronization process of the target access network device according to the downlink synchronization configuration information. This eliminates the need for the terminal device to execute the downlink synchronization process of the target cell again after receiving a handover command. For example, the terminal device receives the reference signal of the target cell based on the downlink synchronization configuration information to obtain the downlink timing information of the target cell. This eliminates the time required for the downlink synchronization process during the interruption, thus shortening the interruption duration. Optionally, the downlink synchronization process may include a coarse synchronization process and / or a fine synchronization process.

[0242] It is understandable that S703 can also be replaced by: the terminal device executing the access procedure to the target cell according to the above handover command, which is completed through a random access procedure. That is, if the terminal device only performed the downlink synchronization procedure of the target cell before step S702, the terminal device still accesses the target cell through a random access procedure, and the reduced interruption time is the time saved by performing downlink synchronization in advance.

[0243] Optionally, Figure 7 The method 700 shown further includes: before the terminal device performs the access procedure to the target cell according to the handover command, it sends a preamble according to the random access configuration information.

[0244] In one possible implementation, after receiving configuration information (including random access configuration information), the terminal device sends a preamble to the target access network device according to the random access configuration information. This enables the terminal device to perform a non-random access procedure to the target cell after receiving a handover command. In this way, the time required for the uplink synchronization process is eliminated from the interruption time, which helps to shorten the interruption duration.

[0245] After the terminal device sends the preamble, it can obtain the TA using any of the following methods:

[0246] Method 1: The terminal device receives a first message (such as RAR), which is used to respond to the aforementioned preamble and carries a TA. Optionally, this first message is sent to the terminal device by the target access network device.

[0247] In Method 1, after sending the preamble to the target access network device, the terminal device continues to monitor the RAR from the target access network device in the RAR window, thereby obtaining the TA from the RAR as soon as possible.

[0248] Method 2: The TA (Transmission Aspect) is carried in the handover command; in other words, the handover command includes the TA. As one possible implementation, after receiving the preamble, the target access network device sends the TA to the source access network device. The source access network device then sends a handover command to the terminal device, indicating a handover to the target cell; this handover command includes the TA.

[0249] In method two, after sending the preamble to the target access network device, the terminal device returns to the source access network device to continue data transmission, instead of continuing to monitor the RAR from the target access network device. This reduces data interruption time between the terminal device and the source access network device, preventing a degraded service experience.

[0250] As can be seen from the above scheme, before the terminal device receives the handover command to disconnect from the source access network device, it can receive the random access configuration information and / or downlink synchronization configuration information of the target cell. This allows the terminal device to perform the uplink and / or downlink synchronization process with the target cell in advance. For example, it can perform the uplink and / or downlink synchronization process with the target cell before receiving the handover command, or it can perform the uplink and / or downlink synchronization process with the target cell before performing the access process to the target cell based on the handover command. In this way, after the terminal device receives the handover command to disconnect from the source access network device, it does not need to perform the uplink and / or downlink synchronization process with the target cell, thereby helping to reduce the interruption time. For example, see... Figure 4 The interrupt time composition eliminates the time required for the uplink and / or downlink synchronization process after the terminal device receives the handover command, thus shortening the length of the interrupt time.

[0251] Figure 7 The method shown in 700 and Figure 3 The difference between the existing methods 300 shown is that in method 300, the handover command includes random access configuration information, and the terminal device performs uplink and / or downlink synchronization with the target cell after receiving the handover command. In method 700, the source access network device sends the random access configuration information and / or downlink synchronization configuration information before sending the handover command. This allows the terminal device to perform the uplink and / or downlink synchronization with the target cell in advance (e.g., before receiving the handover command), so that the terminal device does not need to perform the uplink and / or downlink synchronization with the target cell after receiving the handover command, thereby reducing the interruption time.

[0252] In one possible implementation, Figure 7The method 700 further includes: before receiving configuration information, the terminal device sending first information, the first information indicating at least one of the following: a predicted measurement result of a first cell, the first cell including a target cell; or a predicted measurement event related to the first cell, the first cell including the target cell. Optionally, the first cell also includes a serving cell (source cell). The first cell includes one or more neighboring cells.

[0253] The measurement results described above can be at the cell level or at the beam level, and this application does not limit them. The measurement events described above can be, for example, the A3 event, the A5 event, or other events mentioned above, and this application does not limit them.

[0254] In one possible implementation, the terminal device reports the predicted measurement results of neighboring cells and serving cells to the source access network device, whereby the neighboring cells include the aforementioned target cell. Correspondingly, the source access network device receives the predicted measurement results of neighboring cells and serving cells and, based on these results, makes a handover decision, such as which cell to hand over to and when to trigger the handover. The measurement results may include measurements such as the received signal strength indicator (RSSI), reference signal received power (RSRP), reference signal received quality (RSRQ), signal-to-noise ratio (SNR), or signal-to-interference-plus-noise ratio (SINR) of a reference signal such as SSB or CSI-RS.

[0255] In another possible implementation, the terminal device reports predicted measurement events related to neighboring cells and the serving cell to the source access network device, whereby the neighboring cells include the target cell mentioned above. Correspondingly, the source access network device receives the predicted measurement events related to neighboring cells and the serving cell, and based on these events, makes a handover decision, such as which cell to hand over to and when to trigger the handover. For example, the terminal device reports predicted A3 events or A5 events to the source access network device.

[0256] Optionally, the terminal device may also report a predicted radio link failure (RLF) event to the source access network device to trigger a handover decision. The predicted RLF event reported by the terminal device may be a prediction of an RLF occurring at a future point in time, or a prediction of the probability of an RLF occurring at a future point in time or within a time period.

[0257] It should be understood that the events / measurement results reported by the terminal devices above as triggering the access network devices to make handover decisions are merely examples and should not constitute any limitation on this application.

[0258] It should also be understood that the above-described terminal device's prediction and reporting of measurement results / events is merely an example and should not constitute any limitation on this application. The prediction can also be performed by the source access network device. In one possible implementation, the source access network device can predict the measurement results of the first cell and / or measurement events related to the first cell.

[0259] After receiving the first information reported by the terminal device, or after the source access network device predicts the measurement results of the first cell and / or the measurement events related to the first cell, the source access network device can determine the configuration information based on the measurement results of the first cell and / or the measurement events related to the first cell.

[0260] In one possible implementation, the source access network device can determine the target cell based on the measurement results and / or related measurement events of the first cell, and send a handover request to the target access network device, which then receives the handover request. When the target access network device agrees to the handover request, it can send a handover request confirmation to the source access network device. This confirmation carries the configuration information of the target cell, which may include random access configuration information and / or non-random access configuration information. The source access network device then receives this configuration information. Subsequently, the source access network device can forward this configuration information to the terminal device, thereby allowing the terminal device to obtain the configuration information of the target cell.

[0261] The following will combine Figure 8 right Figure 7 The detailed process of method 700 shown is described below.

[0262] Figure 8 This is a detailed flowchart illustrating the switching method provided in the embodiments of this application.

[0263] The terminal device or the source access network device can predict the measurement results of the first cell and / or measurement events related to the first cell, such as when the terminal device performs S801a or the source access network device performs S801b.

[0264] S801a, The terminal device predicts the measurement results of the first cell and / or measurement events related to the first cell.

[0265] S801b, the source access network equipment predicts the measurement results of the first cell and / or measurement events related to the first cell.

[0266] The first residential community mentioned above includes the target residential community. Optionally, the first residential community mentioned above also includes the serving residential community.

[0267] When the terminal device executes S801a, it also executes S802: the terminal device sends first information to the source access network device, the first information indicating at least one of the following: the predicted measurement result of the first cell; or, the predicted measurement event related to the first cell. When the source access network device executes S801b, the terminal device may not execute S802. For a detailed explanation of S802, please refer to [link to relevant documentation]. Figure 7 The relevant descriptions will not be repeated here.

[0268] S801a, S801b, and S802 are optional.

[0269] S803. The source access network device sends configuration information to the terminal device. This configuration information is used to configure the target cell and includes random access configuration information. Correspondingly, the terminal device receives the above configuration information.

[0270] Optionally, the above configuration information may also include random access-free configuration information. When the above configuration information does not include random access-free configuration information, the handover command described below may include random access-free configuration information.

[0271] It is understood that the aforementioned configuration information can be sent from the target access network device to the source access network device, and then forwarded by the source access network device to the terminal device. For example, the source access network device can determine the target cell based on the first information and send a handover request to the target access network device. This handover request may include the measurement results of the first cell and / or measurement events related to the first cell. Correspondingly, the target access network device receives the handover request. When the target access network device agrees to the handover request, it can send a handover request confirmation to the source access network device. This confirmation carries the configuration information of the target cell. Correspondingly, the source access network device receives the configuration information and forwards it to the terminal device, thereby allowing the terminal device to obtain the configuration information of the target cell.

[0272] For a detailed explanation of S803, please refer to [link / reference]. Figure 7 The relevant descriptions will not be repeated here.

[0273] Optionally, the above configuration information includes downlink synchronization configuration information, and the terminal device performs the downlink synchronization process according to the downlink synchronization configuration information.

[0274] It is understood that if the above configuration information only includes downlink synchronization configuration information, then the handover command described below may include uplink synchronization configuration information. After receiving the handover command, the terminal device can perform a random access procedure based on the uplink synchronization configuration information, and the reduced interruption time is the time saved by the downlink synchronization performed in advance. If the above configuration information includes both uplink synchronization configuration information and downlink synchronization configuration information, then after receiving the handover command, the terminal device can perform a random access procedure without random access, and the reduced interruption time is the time saved by the downlink and uplink synchronization performed in advance.

[0275] S804. The terminal device sends a preamble to the target access network device. Correspondingly, the target access network device receives the preamble.

[0276] After receiving the above configuration information, the terminal device performs an uplink synchronization process to the target cell based on the random access configuration information. For example, the terminal device sends a preamble to the target access network device based on the above random access configuration information, and the target access network device receives the preamble from the terminal device.

[0277] After receiving the preamble, the target access network device instructs the terminal device to send a TA. One possible implementation is that the target access network device executes step S805. In step S805, the target access network device sends a RAR (Real-Agent Record) to the terminal device, which carries the TA. Correspondingly, the terminal device receives the aforementioned RAR.

[0278] Another possible implementation is that the target access network device executes S806. In S806, the target access network device indicates the TA to the source access network device, and correspondingly, the source access network device receives the TA. After receiving the TA, the source access network device can indicate the aforementioned TA to the terminal device, as included in the handover command described below.

[0279] In summary, S805 / S806 are optional.

[0280] S807. The source access network device sends a handover command to the terminal device, which indicates the handover to the target cell. Correspondingly, the terminal device receives the handover command.

[0281] S808, The terminal device executes a non-random access procedure to the target cell.

[0282] For example, the terminal device sends uplink signaling, such as an RRC reconfiguration completion message or a MAC CE, to the target access network device based on the random access-free configuration information. This uplink signaling is used to indicate to the access network device that the access process is complete. Correspondingly, the access network device receives the aforementioned uplink signaling. Optionally, the access network device may also send a response message to the terminal device, such as sending a MAC CE acknowledgment.

[0283] This application also provides a handover method. The source access network device sends random access configuration information and a first-time indication before a first-time interval. Correspondingly, after receiving the random access configuration information, the terminal device performs an uplink synchronization process with the target cell before the first-time interval, and disconnects from the source access network device at the first-time interval to perform an access process to the target cell. This helps reduce the interruption time during the handover process (such as the time required for the uplink synchronization process). Optionally, the source access network device can also send downlink synchronization configuration information before the first-time interval so that the terminal can perform a downlink synchronization process with the target cell before the first-time interval. Thus, the reduced interruption time includes the time required for the downlink synchronization process.

[0284] Figure 9 This is a flowchart illustrating another switching method 900 provided in an embodiment of this application. Method 900 is applicable to... Figure 1 The communication system 10 shown or Figure 2 The communication system shown, method 900 includes the following steps:

[0285] S901. The source access network device sends a handover command to the terminal device. This handover command indicates the handover to the target cell and includes random access configuration information and second information, the second information indicating the first moment. Correspondingly, the terminal device receives the handover command.

[0286] The aforementioned "first moment" can be understood as the moment that triggers the switch, such as... Figure 6 The time shown is t2.

[0287] Understandably, in Figure 9In the illustrated embodiment, the terminal device does not execute the access procedure to the target cell after receiving the aforementioned handover command, but rather executes the access procedure to the target cell at the first moment. That is, the terminal device receives the handover command before executing the access procedure to the target cell. This handover command includes random access configuration information, so that the terminal device can execute the uplink synchronization procedure with the target cell before the first moment, based on the random access configuration information. Optionally, the handover command may also include downlink synchronization configuration information for the downlink synchronization procedure between the terminal device and the target cell. For example, the downlink synchronization configuration information includes the target cell's reference signal configuration information, such as the period of the SSB or CSI-RS.

[0288] The aforementioned second information is used to indicate the first moment. In one possible implementation, the second information is used to indicate timer information (e.g., the duration of the timer), which is used to determine the first moment. After receiving the aforementioned handover command, the terminal device can start the timer so that when the timer expires / timeouts, it can perform the access process to the target cell.

[0289] Another possible implementation is that the second information mentioned above may include absolute time, such as one or more of the frame number, subframe number, time slot, or symbol.

[0290] For an explanation of random access configuration information, please refer to [link / reference]. Figure 7 This will not be elaborated upon here.

[0291] S902. Before the first moment, the terminal device performs an uplink synchronization process with the target cell based on the random access configuration information. Alternatively, before the first moment, the terminal device performs a downlink synchronization process with the target cell based on the downlink synchronization configuration information. In this case, when the first moment arrives, the terminal performs an uplink synchronization process with the target cell.

[0292] In one possible implementation, the terminal device sends a preamble based on random access configuration information before the first moment. Correspondingly, the target access network device receives the preamble. Further, the target access network device can send a first message to the terminal device, which is used to respond to the preamble and carries a TA (Transactional Acquisition).

[0293] In another possible implementation, the terminal device receives the reference signal of the target cell based on the downlink synchronization configuration information before the first moment, and obtains the downlink timing information of the target cell. Optionally, the downlink synchronization process may include a coarse synchronization process and / or a fine synchronization process.

[0294] S903. Based on the aforementioned second information, the terminal device executes the access process to the target cell at the first moment.

[0295] The terminal device immediately initiates the access process to the target cell. The terminal device immediately disconnects from the source access device.

[0296] Optionally, the handover command may also include the target cell's no-random-access configuration information, which includes CG configuration information and / or DG configuration information. For a detailed explanation of the no-random-access process and the no-random-access configuration information, please refer to [link to relevant documentation]. Figure 7 This will not be elaborated upon here.

[0297] At the first moment, the terminal device, based on the aforementioned random access-free configuration information, performs access to the target cell through a random access-free procedure. For example, based on the random access-free configuration information, the terminal device sends uplink signaling, such as an RRC reconfiguration completion message or a MAC CE, to the target access network device. This uplink signaling is used to indicate to the network device that the access procedure is complete. Correspondingly, the access network device receives the aforementioned uplink signaling. Optionally, the access network device may also send a response message to the terminal device, such as sending a MAC CE confirmation.

[0298] It is understandable that the terminal device can also access the target cell through a random access procedure at the first moment, based on the aforementioned random access-free configuration information. That is, if the terminal device only performs the downlink synchronization procedure of the target cell before step S903, the terminal device will still access the target cell through the random access procedure, and the reduced interruption time is the time saved by performing downlink synchronization in advance.

[0299] In one possible implementation, Figure 9 The method 900 further includes, before receiving a handover command, the terminal device sending first information indicating at least one of the following: a predicted measurement result of a first cell, the first cell including a target cell; or a predicted measurement event related to the first cell, the first cell including the target cell. Optionally, the first cell also includes a serving cell (source cell). The first cell includes one or more neighboring cells.

[0300] The measurement results described above can be at the cell level or at the beam level, and this application does not limit them. The measurement events described above can be, for example, the A3 event, the A5 event, or other events mentioned above, and this application does not limit them.

[0301] In one possible implementation, the terminal device reports predicted measurement results of neighboring and serving cells, including the target cell, to the source access network device. Correspondingly, the source access network device receives the predicted measurement results of neighboring and serving cells and, based on these results, makes a handover decision, such as which cell to hand over to and when to trigger the handover. The measurement results may include measurements such as RSRP / RSRQ / SNR / SINR of reference signals like SSB or CSI-RS.

[0302] In another possible implementation, the terminal device reports predicted measurement events related to neighboring cells and the serving cell to the source access network device, whereby the neighboring cells include the target cell mentioned above. Correspondingly, the source access network device receives the predicted measurement events related to neighboring cells and the serving cell, and based on these events, makes a handover decision, such as which cell to hand over to and when to trigger the handover. For example, the terminal device reports predicted A3 events or A5 events to the source access network device.

[0303] Optionally, the terminal device may also report predicted RLF events to the source access network device to trigger a handover decision. The predicted RLF event reported by the terminal device may be a prediction of an RLF occurring at a future point in time, or a prediction of the probability of an RLF occurring at a future point in time or within a time period.

[0304] It should be understood that the events / measurement results reported by the terminal devices above as triggering the access network devices to make handover decisions are merely examples and should not constitute any limitation on this application.

[0305] It should also be understood that the above-described terminal device's prediction and reporting of measurement results / events is merely an example and should not constitute any limitation on this application. The prediction can also be performed by the source access network device. In one possible implementation, the source access network device can predict the measurement results of the first cell and / or measurement events related to the first cell.

[0306] After receiving the first information reported by the terminal device, or after the source access network device predicts the measurement results of the first cell and / or the measurement events related to the first cell, the source access network device can determine the handover command based on the measurement results of the first cell and / or the measurement events related to the first cell.

[0307] In one possible implementation, the source access network device can determine the target cell based on the measurement results and / or related measurement events of the first cell, and send a handover request to the target access network device. This handover request may include the measurement results and / or related measurement events of the first cell. The target access network device receives the handover request. When the target access network device agrees to the handover request, it can send a handover request confirmation to the source access network device. This confirmation carries the configuration information of the target cell, which may include random access configuration information and / or non-random access configuration information. The source access network device receives this configuration information. Subsequently, the source access network device can forward this configuration information to the terminal device, thereby allowing the terminal device to obtain the configuration information of the target cell.

[0308] In one possible implementation, the handover command further includes downlink synchronization configuration for the target cell. This downlink synchronization configuration includes one or more of the following: SSB, CSI-RS configuration, or gap configuration. Optionally, Figure 9 The method 900 shown further includes: the terminal device performing a downlink synchronization process with the target cell before the first moment.

[0309] Figure 9 The method shown is 900 and Figure 3 The difference between the existing methods 300 shown is that in method 300, the terminal device disconnects from the source access network device after receiving the handover command at the first moment and performs a random access procedure to the target cell. In method 900, the terminal device receives the handover command before the first moment, and after receiving the handover command, the terminal device performs an uplink synchronization procedure and / or a downlink synchronization procedure with the target cell before the first moment. The connection with the source access network device is disconnected only at the first moment, and access to the target cell is performed. Therefore, there is no need to perform a random access procedure after the first moment, and the time required for the uplink / downlink synchronization procedure is omitted from the composition of the interruption time, which helps to shorten the interruption duration.

[0310] The following will combine Figure 10 right Figure 9 The detailed process of method 900 shown is described below.

[0311] Figure 10 This is a detailed flowchart illustrating another switching method provided in an embodiment of this application.

[0312] The terminal device or the source access network device can predict the measurement results of the first cell and / or measurement events related to the first cell, such as when the terminal device performs S1001a or the source access network device performs S1001b.

[0313] S1001a, The terminal equipment predicts the measurement results of the first cell and / or measurement events related to the first cell.

[0314] S1001b, The source access network equipment predicts the measurement results of the first cell and / or measurement events related to the first cell.

[0315] The first residential community mentioned above includes the target residential community. Optionally, the first residential community mentioned above also includes the serving residential community.

[0316] When the terminal device executes S1001a, it also executes S1002: the terminal device sends first information to the source access network device, the first information indicating at least one of the following: the predicted measurement result of the first cell; or, the predicted measurement event related to the first cell. When the source access network device executes S1001b, the terminal device may not execute S1002. For a detailed explanation of S1002, please refer to [link to relevant documentation]. Figure 7 The relevant descriptions will not be repeated here.

[0317] S1001a, S1001b, and S1002 are optional.

[0318] S1003. The source access network device sends a handover command to the terminal device. This handover command indicates the handover to the target cell and includes random access configuration information, downlink synchronization configuration, and second information, whereby the second information indicates the first moment. Correspondingly, the terminal device receives the aforementioned handover command.

[0319] It is understood that the aforementioned random access configuration information and downlink synchronization configuration can be sent from the target access network device to the source access network device, and then forwarded by the source access network device to the terminal device. For example, the source access network device can determine the target cell based on the first information and send a handover request to the target access network device. This handover request may include the measurement results of the first cell and / or measurement events related to the first cell. Correspondingly, the target access network device receives the handover request. When the target access network device agrees to the handover request, it can send a handover request confirmation to the source access network device. This confirmation carries the random access configuration information and downlink synchronization configuration of the target cell. Correspondingly, the source access network device receives the random access configuration information and downlink synchronization configuration and forwards them to the terminal device, thereby allowing the terminal device to obtain the random access configuration information and downlink synchronization configuration of the target cell.

[0320] In one possible implementation, the aforementioned second information is used to indicate timer information, which is used to determine the first moment. After receiving the aforementioned handover command, i.e., at moment t1 as shown in the figure, the terminal device can start a timer (the timer duration is T) so that when the timer expires / timeouts (i.e., at moment t2), the access process to the target cell can be executed.

[0321] S1004. The terminal device performs the downlink synchronization process with the target cell.

[0322] For example, the terminal device performs a downlink synchronization process with the target cell based on the downlink synchronization configuration described above.

[0323] For example, the terminal device searches for synchronization signals, such as the primary synchronization signal (PSS) and secondary synchronization signal (SSS), on the frequency band of the target cell. By decoding the PSS and SSS, the terminal device can determine the physical cell ID (PCI) of the target cell. After synchronization, the terminal device needs to decode the physical broadcast channel (PBCH), which contains basic system information of the cell, such as the system frame number (SFN) and cell bandwidth. Further, the terminal device reads the system information block (SIB).

[0324] For example, the terminal device receives CSI-RS in the target cell to obtain the downlink timing information of the target cell. S1005, the terminal device sends a preamble to the target access network device. Correspondingly, the target access network device receives the aforementioned preamble.

[0325] Based on the random access configuration information, the terminal device performs an uplink synchronization process to the target cell. For example, based on the aforementioned random access configuration information, the terminal device sends a preamble to the target access network device, and correspondingly, the target access network device receives the preamble from the terminal device.

[0326] S1006. The target access network device sends a RAR to the terminal device, which carries a TA. Correspondingly, the terminal device receives the aforementioned RAR.

[0327] S1005 and S1006 are optional. If the terminal device only performs the downlink synchronization process before the first moment, then after the first moment arrives, the terminal device can perform the uplink synchronization process. In this case, the reduced interruption time is the time saved by performing the downlink synchronization earlier. S1007: At the first moment, the terminal device performs a random-free access procedure to the target cell.

[0328] For example, the terminal device sends an access request to the target access network device based on the random access-free configuration information, and the access network device receives the access request and sends an access response to the terminal device.

[0329] This application also provides a handover method in which the source access network device can send the configuration information of the target cell in advance (e.g., before the handover time), and the terminal device can maintain the connection with the source cell and access the target cell to transmit data with both the target cell and the source cell, thereby basically achieving zero-interruption time for the terminal device.

[0330] Figure 11 This is a flowchart illustrating another switching method 1100 provided in an embodiment of this application. Method 1100 is applicable to... Figure 1 The communication system 10 shown or Figure 2 The communication system shown, method 1100 includes the following steps:

[0331] S1101, the terminal device sends first information to the source access network device, the first information indicating at least one of the following: a predicted measurement result of the first cell; or a predicted measurement event related to the first cell. Correspondingly, the source access network device receives the aforementioned first information.

[0332] The first cell mentioned above includes the target cell. Optionally, the first cell also includes a serving cell. The first cell includes one or more neighboring cells, which in turn include the target cell.

[0333] The measurement results described above can be at the cell level or at the beam level, and this application does not limit them. The measurement events described above can be, for example, the A3 event, the A5 event, or other events mentioned above, and this application does not limit them.

[0334] In one possible implementation, the terminal device reports predicted measurement results of neighboring and serving cells, including the target cell, to the source access network device. Correspondingly, the source access network device receives the predicted measurement results of neighboring and serving cells and, based on these results, makes a handover decision, such as which cell to hand over to and when to trigger the handover. The measurement results may include measurements such as RSRP / RSRQ / SNR / SINR of reference signals like SSB or CSI-RS.

[0335] In another possible implementation, the terminal device reports predicted measurement events related to neighboring cells and the serving cell to the source access network device, whereby the neighboring cells include the target cell mentioned above. Correspondingly, the source access network device receives the predicted measurement events related to neighboring cells and the serving cell, and based on these events, makes a handover decision, such as which cell to hand over to and when to trigger the handover. For example, the terminal device reports predicted A3 events or A5 events to the source access network device.

[0336] Optionally, the terminal device may also report predicted RLF events to the source access network device to trigger a handover decision. The predicted RLF event reported by the terminal device may be a prediction of an RLF occurring at a future point in time, or a prediction of the probability of an RLF occurring at a future point in time or within a time period.

[0337] It should be understood that the events / measurement results reported by the terminal devices above as triggering the access network devices to make handover decisions are merely examples and should not constitute any limitation on this application.

[0338] It should also be understood that the above-described terminal device's prediction and reporting of measurement results / events is merely an example and should not constitute any limitation on this application. The prediction can also be performed by the source access network device. In one possible implementation, the source access network device can predict the measurement results of the first cell and / or measurement events related to the first cell.

[0339] The source access network device can determine configuration information based on the aforementioned first information. This configuration information is used to configure the target cell. The configuration information includes the random access configuration information and downlink synchronization configuration of the target cell. In one possible implementation, the source access network device can determine the target cell based on the first information and send a handover request to the target access network device. Correspondingly, the target access network device receives the handover request. When the target access network device agrees to the handover request, it can send a handover request confirmation to the source access network device. This confirmation carries the configuration information of the target cell, which may include random access configuration information and / or downlink synchronization configuration. Correspondingly, the source access network device receives this configuration information.

[0340] S1102. The source access network device sends configuration information to the terminal device, which is used to configure the target cell. Correspondingly, the terminal device receives the above configuration information.

[0341] The configuration information mentioned above may include downlink synchronization configuration and random access configuration information. For a detailed explanation of downlink synchronization configuration and random access configuration information, please refer to the above text, which will not be repeated here.

[0342] In one possible implementation, the source access network device sends configuration information to the terminal device before a first moment. This configuration information is used to configure the target cell and includes downlink synchronization configuration and random access configuration information. The first moment can be a predicted handover time, or a predicted time instructing the terminal device to handover to the target cell, or a time when a handover command is issued based on predicted measurement results. Correspondingly, the terminal device receives the aforementioned configuration information before the first moment.

[0343] S1103. The terminal device accesses the target cell according to the above configuration information.

[0344] For example, the terminal device performs a downlink synchronization process with the target cell based on the downlink synchronization configuration, and performs an uplink synchronization process with the target cell based on the random access configuration information.

[0345] S1104. The terminal device transmits data with the target cell and the source cell.

[0346] The aforementioned data transmission includes uplink data transmission and / or downlink data transmission.

[0347] For example, a terminal device transmits uplink data to a target cell and a source cell. For instance, the terminal device sends a first data packet to the target cell and a second data packet to the source cell, where the first and second data packets are identical; for example, the second data packet may be a copy of the first data packet. The source cell or the target cell can uniformly sort the data packets. For example, the access network device of the source cell forwards the data packets received from the terminal device to the access network device of the target cell, where the access network device of the target cell uniformly sorts the data packets; or the access network device of the target cell forwards the data packets received from the terminal device to the access network device of the source cell, where the access network device of the source cell uniformly sorts the data packets.

[0348] For example, the terminal device transmits downlink data with both the target cell and the source cell. For instance, the core network device can send new / later downlink data to the target cell, and the target access network device sends it to the terminal device. The core network device can also send earlier downlink data to the source cell, and the source access network device sends it to the terminal device. Here, the new / later downlink data can be downlink data occurring after a certain point in time.

[0349] It is understandable that when the signal quality of the source cell deteriorates to a certain level, such as below a threshold, the terminal device can disconnect from the source cell (source access network device). One possible implementation is that the source access network device sends a third message to the terminal device, indicating the release of the connection with the source access network device. The source access network device can also send a fourth message to the core network device, indicating the release of the connection with the source access network device.

[0350] Another possible implementation is that the source access network device sends a third message to the terminal device, which indicates the release of the connection with the source access network device, and sends a fifth message to the target access network device, which indicates the release of the connection with the source access network device. The target access network device then forwards the fifth message to the core network device.

[0351] Another possible implementation is that the target access network device sends a sixth message to the terminal device, which indicates the release of the connection with the source access network device, and sends a fifth message to the core network device, which also indicates the release of the connection with the source access network device.

[0352] Optionally, before the terminal device accesses the target cell, the source access network device can forward the downlink data received from the core network device to the target access network device.

[0353] The following will combine Figure 12 right Figure 11 The detailed process of method 1100 shown is described below.

[0354] Figure 12 This is a detailed flowchart illustrating another switching method provided in the embodiments of this application.

[0355] The terminal device or the source access network device can predict the measurement results of the first cell and / or measurement events related to the first cell, such as when the terminal device performs S1201a or the source access network device performs S1201b.

[0356] S1201a, The terminal equipment predicts the measurement results of the first cell and / or measurement events related to the first cell.

[0357] S1201b, The source access network equipment predicts the measurement results of the first cell and / or measurement events related to the first cell.

[0358] The first residential community mentioned above includes the target residential community. Optionally, the first residential community mentioned above also includes the serving residential community.

[0359] When the terminal device executes S1201a, it also executes S1202: the terminal device sends first information to the source access network device, the first information indicating at least one of the following: the predicted measurement result of the first cell; or, the predicted measurement event related to the first cell. When the source access network device executes S1201b, the terminal device may not execute S1202. For a detailed explanation of S1202, please refer to [link to relevant documentation]. Figure 7 The relevant descriptions will not be repeated here.

[0360] S1201a, S1201b and S1202 are optional.

[0361] S1203. The terminal equipment and the target cell perform the handover preparation process.

[0362] For example, the terminal device sends a handover request to the target access network device, and the target access network device receives the handover request. When the target access network device agrees to the handover request, it can send a handover request confirmation to the source access network device. This confirmation carries the configuration information of the target cell, and the source access network device receives the confirmation. The configuration information of the target cell includes downlink synchronization configuration and / or random access configuration information.

[0363] S1204. The source access network device sends configuration information to the terminal device, which is used to configure the target cell. Correspondingly, the terminal device receives the above configuration.

[0364] The aforementioned configuration information includes downlink synchronization configuration and / or random access configuration information. For example, the source access network device may send configuration information to the terminal device before a first moment, and correspondingly, the terminal device receives the aforementioned configuration information before the first moment, which is a handover time determined based on the predicted measurement results / measurement events of the first cell.

[0365] S1205. The core network equipment sends downlink data to the source access network equipment. Correspondingly, the source access network equipment receives downlink data from the core network equipment.

[0366] S1206. The source access network device forwards downlink data to the target access network device.

[0367] Before a terminal device accesses the target cell, the source access network device can forward downlink data from the core network device to the target access network device.

[0368] S1207. The terminal device performs the downlink synchronization process with the target cell.

[0369] For example, the terminal device performs a downlink synchronization process with the target cell based on the downlink synchronization configuration of the target cell.

[0370] S1208. The terminal device sends a preamble to the target access network device. Correspondingly, the target access network device receives the preamble.

[0371] The terminal device sends a preamble to the target access network device based on random access configuration information. Correspondingly, the target access network device receives the preamble.

[0372] S1209. The target access network device sends a RAR to the terminal device. Correspondingly, the terminal device receives the aforementioned RAR.

[0373] S1210, The target access network device indicates a path switch to the core network device.

[0374] For example, the target access network device sends a path handover request message to the AMF network element. This message indicates that the terminal device has established a connection with the target cell. The path handover request message may include the target cell identifier and a list of PDU sessions to be switched (indicating the PDU sessions established by the target access network device for the terminal device). Correspondingly, the AMF network element can receive the path handover request message from the target access network device and send a path handover response message to it.

[0375] This path switching message can instruct core network elements that the terminal device can communicate with the target access network device while communicating with the source access network device.

[0376] S1211. The terminal device transmits data with the target access network device and the source access network device.

[0377] For example, the terminal device performs uplink data transmission with both the target cell and the source cell. For instance, the terminal device sends a first data packet to the target cell and a second data packet to the source cell, wherein the first and second data packets are identical, such as the second data packet being a copy of the first data packet. The source and target cells can uniformly sort the data packets.

[0378] For example, the terminal device performs downlink data transmission with both the target cell and the source cell. For instance, the core network device can send later downlink data to the target cell, which in turn sends it to the terminal device; conversely, the core network device can send earlier downlink data to the source cell, which in turn sends it to the terminal device.

[0379] It is understandable that when the signal quality of the source cell deteriorates to a certain level, such as when the signal quality falls below a threshold, the terminal device can disconnect from the source cell (source access network device). For example, the terminal device, the target access network device, and the source access network device execute S1212.

[0380] S1212, the source access network device sends a third message to the terminal device, the third message indicating the release of the connection with the source access network device, and the source access network device sends a fourth message to the core network device, the fourth message indicating the release of the connection with the source access network device.

[0381] The above instructions for releasing the connection with the source access network device are merely examples; more methods can be found by referring to [the documentation / reference]. Figure 11 The relevant descriptions will not be repeated here.

[0382] S1213. The terminal equipment transmits data with the target access network equipment.

[0383] It should be noted that the order of the methods listed above does not imply the order of execution. The execution order of each process should be determined by its function and internal logic.

[0384] Additionally, the embodiments shown above (such as...) Figures 7 to 12 The embodiments shown can be used individually or in combination, and the steps between the various embodiments can also be partially combined; this application does not limit this. For example, Figure 7 The illustrated embodiments and Figure 11 When the embodiments shown are used in combination, after the terminal device executes S702, that is, after receiving the handover command, it can maintain the connection with the source cell and access the target cell through the random access-free procedure.

[0385] The switching method of the embodiments of this application has been described in detail above. The communication device of the embodiments of this application will be described in detail below. The communication device includes modules or units for executing each part of the above embodiments. The modules or units can be software, hardware, or a combination of software and hardware. The following only provides a brief illustrative example of the communication device. For details of the implementation, please refer to the description of the foregoing method embodiments; further details will not be repeated below.

[0386] Figure 13 This is a schematic block diagram of a communication device 1300 provided in an embodiment of this application. Figure 13 As shown, the communication device 1300 includes a transceiver module 1301 and a processing module 1302.

[0387] In one possible implementation, the communication device 1300 is used to implement the steps corresponding to the terminal device (an example of the first communication device) in the method 700 described above.

[0388] The transceiver module 1301 is used to receive configuration information, which is used to configure the target cell. The configuration information includes random access configuration information, which is used to perform the uplink synchronization process with the target cell. The transceiver module 1301 is also used to receive a handover command, which is used to indicate handover to the target cell. The processing module 1302 is used to perform the access process to the target cell according to the handover command. The access process is completed through a random access-free process.

[0389] Optionally, the transceiver module 1301 is further configured to send first information before receiving configuration information, the first information being used to indicate at least one of the following: a predicted measurement result of a first cell, the first cell including the target cell; or a predicted measurement event related to the first cell, the first cell including the target cell.

[0390] Optionally, the above configuration information may also include random access-free configuration information, or the above handover command may include random access-free configuration information, which may include CG configuration information and / or DG configuration information.

[0391] Optionally, the transceiver module 1301 is also configured to send a preamble based on random access configuration information before performing the access procedure to the target cell according to the handover command.

[0392] Optionally, the transceiver module 1301 is also configured to receive a first message, which is used to respond to a preamble and carries a TA.

[0393] Optionally, the switching command mentioned above includes TA.

[0394] In another possible implementation, the communication device 1300 is used to implement the steps corresponding to the source access network device (an example of the second communication device) in the method 700 described above.

[0395] The transceiver module 1301 is used to send configuration information, which is used to configure the target cell. The configuration information includes random access configuration information, which is used to perform the uplink synchronization process with the target cell. The transceiver module 1301 sends a handover command, which is used to indicate handover to the target cell.

[0396] Optionally, the transceiver module 1301 is further configured to receive first information before sending configuration information, the first information being used to indicate at least one of the following: a predicted measurement result of a first cell, the first cell including a target cell; or a predicted measurement event related to a first cell, the first cell including a target cell.

[0397] Optionally, the processing module 1302 is used to determine configuration information based on the first information.

[0398] Optionally, the above configuration information may also include random access-free configuration information, or the above handover command may include random access-free configuration information, which may include CG configuration information and / or DG configuration information.

[0399] Optionally, the switching command mentioned above includes TA.

[0400] In one possible implementation, the communication device 1300 is used to implement the steps corresponding to the terminal device (an example of the first communication device) in the method 900 described above.

[0401] The transceiver module 1301 is used to receive a handover command, which instructs the terminal device to hand over to the target cell. The handover command includes random access configuration information and second information, which instructs the terminal device to hand over to the target cell at a first moment. The processing module 1302 is used to perform an uplink synchronization process with the target cell before the first moment, based on the random access configuration information. The processing module 1302 is also used to perform an access process to the target cell at the first moment, based on the second information.

[0402] Optionally, the transceiver module 1301 is further configured to send first information before receiving a handover command, the first information being used to indicate at least one of the following: a predicted measurement result of a first cell, the first cell including the target cell; or a predicted measurement event related to the first cell, the first cell including the target cell.

[0403] Optionally, the handover command may also include random access-free configuration information of the target cell, which includes CG configuration information and / or DG configuration information.

[0404] Optionally, the processing module 1302 is specifically used to perform access to the target cell through a random access-free procedure at a first moment, based on the second information.

[0405] Optionally, the processing module 1302 is specifically used to send a preamble according to the random access configuration information before the first moment.

[0406] Optionally, the transceiver module 1301 is also configured to receive a first message, which is used to respond to a preamble and carries a TA.

[0407] Optionally, the second information mentioned above is used to indicate timer information, which is used to determine the first moment.

[0408] Optionally, the processing module 1302 is also configured to start a timer after receiving a switching command.

[0409] In another possible implementation, the communication device 1300 is used to implement the steps corresponding to the source access network device (an example of the second communication device) in the method 900 described above.

[0410] The transceiver module 1301 is used to send a handover command, which instructs the terminal device to hand over to the target cell. The handover command includes random access configuration information and second information. The second information is used to indicate a first moment. The random access configuration information is used to perform the uplink synchronization process with the target cell.

[0411] Optionally, the transceiver module 1301 is further configured to receive first information before sending a handover command, the first information indicating at least one of the following: a predicted measurement result of a first cell, the first cell including the target cell; or a predicted measurement event related to the first cell, the first cell including the target cell.

[0412] Optionally, the processing module 1302 is used to determine the switching command based on the first information.

[0413] Optionally, the above handover command may also include: random access-free configuration information of the target cell, which includes CG configuration information and / or DG configuration information.

[0414] Optionally, the second information mentioned above is used to indicate timer information, which is used to determine the first moment.

[0415] In one possible implementation, the communication device 1300 is used to implement the steps corresponding to the terminal device (an example of the first communication device) in the method 1100 described above.

[0416] The transceiver module 1301 is used to send first information, which indicates at least one of the following: a predicted measurement result of a first cell, the first cell including a target cell; or a predicted measurement event related to the first cell, the first cell including a target cell; the transceiver module 1301 is also used to receive configuration information, which is used to configure the target cell; the processing module 1302 is used to access the target cell according to the configuration information; the transceiver module 1301 is also used to transmit data with the target cell and the source cell.

[0417] Optionally, the transceiver module 1301 is specifically used to send a first data packet to the target cell and a second data packet to the source cell, wherein the first data packet and the second data packet are the same.

[0418] Optionally, the transceiver module 1301 is also configured to receive third information, which is used to indicate the release of the connection with the source access network device, the source access network device being the device that provides services to the source cell.

[0419] In one possible implementation, the communication device 1300 is used to implement the steps corresponding to the source access network device (an example of the second communication device) in the method 1100 described above.

[0420] The transceiver module 1301 is configured to receive first information, which indicates at least one of the following: a predicted measurement result of a first cell, the first cell including a target cell; or a predicted measurement event related to the first cell, the first cell including a target cell; the transceiver module 1301 is also configured to send configuration information according to the first information, which is used to configure the target cell.

[0421] Optionally, the transceiver module 1301 is also used to receive downlink data from the core network equipment and send the downlink data to the target access network equipment, which provides services to the target cell.

[0422] Optionally, the transceiver module 1301 is also used to send third information to the terminal device, which is used to indicate the release of the connection with the source access network device, the source access network device providing services to the source cell.

[0423] Optionally, the transceiver module 1301 is also configured to send a fourth message to the core network device, the fourth message being used to indicate the release of the connection with the source access network device, which provides services to the source cell.

[0424] It should be understood that the communication device 1300 here is embodied in the form of a functional module. The term "module" here can refer to application-specific integrated circuits (ASICs), electronic circuits, processors (e.g., shared processors, proprietary processors, or group processors, etc.) and memories for executing one or more software or firmware programs, combined logic circuits, and / or other suitable components supporting the described functions. In an alternative example, those skilled in the art will understand that the communication device 1300 can be specifically a terminal device or access network device (such as a source access network device) in the above embodiments. The communication device 1300 can be used to execute the various processes and / or steps corresponding to the terminal device or access network device in the above method embodiments; to avoid repetition, these will not be described again here.

[0425] The aforementioned communication device 1300 has the function of implementing the corresponding steps performed by the terminal device or access network device in the above method; the above functions can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. In the embodiments of this application, Figure 13 The communication device 1300 in the text can also be a chip, such as a SoC.

[0426] It should be understood that the module division in the embodiments of this application is illustrative and only represents a logical functional division. In actual implementation, there may be other division methods. Furthermore, the functional modules in the various embodiments of this application can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0427] Figure 14 This is a schematic block diagram of another communication device 1400 provided in the embodiments of this application.

[0428] The communication device 1400 can be a chip system, or it can be an apparatus configured with a chip system to implement the methods described in the above-described method embodiments. In the embodiments of this application, the chip system can be composed of chips, or it can include chips and other discrete devices.

[0429] like Figure 14 As shown, the communication device 1400 may include a processor 1410, which can be used to execute computer programs or instructions stored in memory to achieve... Figures 7 to 12 The steps performed by the terminal device or the source access network device in any of the embodiments shown.

[0430] The communication device 1400 also includes a communication interface 1420. The communication interface 1420 can be used to communicate with other devices via a transmission medium, thereby enabling the communication device 1400 to communicate with other devices. The communication interface 1420 can be, for example, a transceiver, interface, pin, bus, circuit, or a device capable of transmitting and receiving functions. The processor 1410 can utilize the communication interface 1420 to input and output data and to implement... Figures 7 to 12 The steps performed by the source access network device or terminal device in any of the embodiments shown.

[0431] In one possible implementation, the communication device 1400 further includes at least one memory 1430 for storing program instructions and / or data. The memory 1430 is coupled to the processor 1410. The coupling in this embodiment is an indirect coupling or communication connection between devices, units, or modules, and can be electrical, mechanical, or other forms, used for information exchange between devices, units, or modules. The processor 1410 may operate in conjunction with the memory 1430. The processor 1410 may execute program instructions stored in the memory 1430. At least one of the at least one memory may be included in the processor.

[0432] It should be understood that the coupling in the embodiments of this application is an indirect coupling or communication connection between devices, units, or modules, which can be electrical, mechanical, or other forms, used for information interaction between devices, units, or modules. The processor 1410 may operate in conjunction with the memory 1430. The embodiments of this application do not limit the specific connection medium between the processor 1410, communication interface 1420, and memory 1430. Optionally, the processor 1410, communication interface 1420, and memory 1430 are connected via a bus 1440. The bus 1440 is... Figure 14 The connections between other components are shown in bold lines only and are not intended to be limiting. The bus can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, Figure 14 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0433] Figure 15 This is a schematic block diagram illustrating the network element function division and protocol layer structure of the O-RAN device provided in the embodiments of this application.

[0434] In some examples, the control unit (CU) is a logical node that carries the Radio Resource Control (RRC) layer, Service Data Adaptation Protocol (SDAP) layer, Packet Data Convergence Protocol (PDCP) layer, and other control functions of the access network equipment. The CU connects to network nodes such as core network equipment through interfaces, which may be E2 interfaces, etc. Optionally, the CU may possess some of the functions of the core network equipment. The CU (e.g., the PDCP layer and higher layers) connects to distributed units (DUs) (e.g., the Radio Link Control (RLC) layer and lower layers) through interfaces, which may be F1 interfaces, etc. In some examples, these interfaces (e.g., the F1 interface) can provide control plane (CP) and user plane (UP) functions, such as interface management, system information management, UE context management, and RRC message transmission. F1AP is the application protocol of the F1 interface, defining the F1 signaling procedures in some examples. The F1 interface supports control plane F1-C and user plane F1-U.

[0435] In some examples, the CU can be split into CU-CP (control unit-control plane) and CU-UP (control unit-user plane). CU-CP is a logical node carrying the Radio Resource Control (RRC) layer and the PDCP-C (control plane part of PDCP) layer, used to implement the CU's control plane functions. CU-CP can interact with network elements in the core network used to implement control plane functions. These network elements in the core network can be Access and Mobility Function (AMF) network elements, such as the AMF network element in a 5G system. AMF network elements are responsible for mobility management in the mobile network, such as terminal device location updates, terminal device registration with the network, and terminal device handover. CU-UP is a logical node carrying the SDAP layer and the PDCP-U (user plane part of PDCP) layer, used to implement the CU's user plane functions. CU-UP can interact with network elements in the core network used to implement user plane functions. These network elements in the core network, such as the UPF network element in a 5G system, are responsible for data forwarding and receiving in terminal devices. The above CU and DU configurations are merely examples; the functions of the CU and DU can be configured as needed. For instance, the CU or DU can be configured to have more protocol layer functions, or only some protocol layer processing functions. For example, some RLC layer functions and protocol layer functions above the RLC layer can be placed in the CU, while the remaining RLC layer functions and protocol layer functions below the RLC layer can be placed in the DU. Furthermore, the functions of the CU or DU can be divided according to service type or other system requirements, such as by latency. Functions that require low latency can be placed in the DU, while functions that do not require low latency can be placed in the CU.

[0436] In some examples, a DU is a logical node that carries the RLC layer, MAC layer, higher physical layer (higher PHY) layer, and other functions. In some examples, a DU can control at least one RU. The DU connects to the RU through interfaces, which can be fronthaul interfaces. In some examples, the higher PHY layer includes the PHY layer processing components, such as forward error correction (FEC) encoding and decoding, scrambling, modulation, and demodulation.

[0437] In some examples, the RU is a logical node carrying both lower physical layer (PHY) and radio frequency (RF) processing, also known as RF chain. In some examples, the RU can be a 3rd generation partnership project (3GPP) transmission reception point (TRP), a remote radio head (RRH), or other similar entities. In some examples, the low-PHY includes PHY processing functions such as fast Fourier transform (FFT), IFFT, digital beamforming, and filtering. The RU communicates with one or more UEs via a radio link.

[0438] The DU and RU may or may not be co-located. The DU and RU exchange control plane and user plane information via a lower-layer split-control, user, and synchronization (LLS-CUS) interface through a fronthaul link. LLS-CUS may include LLS-C and LLS-U interfaces, respectively providing the control plane and user plane. In some examples, the control plane refers to real-time control between the DU and RU. The DU and RU exchange management information via an LLS-M interface on the fronthaul link; the management plane (M-plane) refers to non-real-time management operations between the DU and RU.

[0439] DU and RU can cooperate to implement the functions of the PHY layer. A DU can be connected to one or more RUs. The functions of DU and RU can be configured in various ways depending on the design. For example, a DU can be configured to implement baseband functions, and an RU can be configured to implement mid-RF functions. Another example is that a DU can be configured to implement higher-level functions in the PHY layer, and an RU can be configured to implement lower-level functions in the PHY layer, or to implement both lower-level and RF functions. Higher-level functions in the physical layer can include a portion of the physical layer's functions that are closer to the MAC layer, while lower-level functions in the physical layer can include another portion of the physical layer's functions that are closer to the mid-RF side.

[0440] exist Figure 7 In the illustrated embodiment, S701 can be specifically implemented as follows: the DU corresponding to the access network device sends configuration information through the RU. In the O-RAN system, S701 can be specifically implemented as follows: the O-DU corresponding to the access network device sends the aforementioned configuration information through the O-RU.

[0441] In a specific implementation of S702, the DU corresponding to the access network device sends a handover command through the RU. In the O-RAN system, the specific implementation of S702 can be that the O-DU corresponding to the access network device sends a handover command through the O-RU.

[0442] exist Figure 9 In the illustrated embodiment, S901 can be specifically implemented as follows: the DU corresponding to the access network device sends a handover command through the RU. In the O-RAN system, S901 can be specifically implemented as follows: the O-DU corresponding to the access network device sends a handover command through the O-RU.

[0443] exist Figure 11 In the illustrated embodiment, S1101 can be specifically implemented as follows: the DU corresponding to the access network device sends the first information through the RU. In the O-RAN system, S1101 can be specifically implemented as follows: the O-DU corresponding to the access network device sends the first information through the O-RU.

[0444] In a specific implementation, S1102 can be implemented as follows: the DU corresponding to the access network device sends configuration information through the RU. In the O-RAN system, S1102 can be implemented as follows: the O-DU corresponding to the access network device sends configuration information through the O-RU.

[0445] This application also provides a computer program product, which includes: a computer program (also referred to as code or instructions), which, when run, can achieve... Figures 7 to 12 The steps performed by the source access network device or terminal device in any of the embodiments shown.

[0446] This application also provides a computer-readable storage medium storing a computer program (also referred to as code or instructions). When the computer program is executed, it can achieve... Figures 7 to 12 The steps performed by the source access network device or terminal device in any of the embodiments shown.

[0447] It should be understood that the processor in the embodiments of this application can be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method embodiments can be completed by the integrated logic circuits in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a microprocessor unit (MPU), a microcontroller unit (MCU), a graphics processing unit (GPU), an artificial intelligence processor (AI processor) or a neural processing unit (NPU), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or a combination of one or more discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software module can reside in a mature storage medium in the field, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method.

[0448] It should also be understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be ROM, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be a cache, 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 synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory used in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0449] The terms "unit," "module," etc., used in this specification can be used to refer to computer-related entities, hardware, firmware, combinations of hardware and software, software, or software in execution. In the embodiments of this application, "unit" and "module" have the same meaning and can be used interchangeably.

[0450] Those skilled in the art will recognize that the various illustrative logical blocks and steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application. In the several embodiments provided in this application, it should be understood that the disclosed apparatus, devices, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the shown or discussed mutual couplings or direct couplings or communication connections may be through some interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0451] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0452] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0453] In the above embodiments, the functions of each functional unit can be implemented entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions (programs). When the computer program instructions (programs) are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital video discs, DVDs), or semiconductor media (e.g., solid-state drives, SSDs), etc.

[0454] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the technology, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0455] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A switching method, characterized in that, include: Receive configuration information, the configuration information being used to configure a target cell, the configuration information including random access configuration information, the random access configuration information being used to execute an uplink synchronization process with the target cell; Receive a handover command, the handover command being used to instruct handover to the target cell; The handover command is used to execute an access procedure to the target cell, which is completed through a random access procedure.

2. The method as described in claim 1, characterized in that, The method further includes: Before receiving the configuration information, first information is sent, the first information indicating at least one of the following: The predicted measurement results for the first cell, which includes the target cell; or Predicted measurement events related to a first cell, which includes the target cell.

3. The method as described in claim 1 or 2, characterized in that, The configuration information also includes random access-free configuration information, or the switching command includes the random access-free configuration information, which includes configuration authorization CG configuration information and / or dynamic authorization DG configuration information.

4. The method according to any one of claims 1 to 3, characterized in that, The method further includes: Before executing the access procedure to the target cell according to the handover command, a preamble is sent according to the random access configuration information.

5. The method as described in claim 4, characterized in that, The method further includes: Receive a first message, which is used to respond to the preamble, and the first message carries a timing advance amount TA.

6. The method according to any one of claims 1 to 4, characterized in that, The switching command includes TA.

7. A switching method, characterized in that, include: Send configuration information, which is used to configure the target cell. The configuration information includes random access configuration information, which is used to perform the uplink synchronization process with the target cell. Send a handover command, which indicates that the user should hand over to the target cell.

8. The method as described in claim 7, characterized in that, The method further includes: Before sending the configuration information, first information is received, the first information indicating at least one of the following: The predicted measurement results for the first cell, which includes the target cell; or Predicted measurement events related to a first cell, which includes the target cell.

9. The method as described in claim 8, characterized in that, The method further includes: Based on the first information, the configuration information is determined.

10. The method according to any one of claims 7 to 9, characterized in that, The configuration information also includes random access-free configuration information, or the switching command includes the random access-free configuration information, which includes configuration authorization CG configuration information and / or dynamic authorization DG configuration information.

11. The method according to any one of claims 7 to 10, characterized in that, The switching command includes a timing advance measure (TA).

12. A switching method, characterized in that, include: A handover command is received, which instructs the terminal device to hand over to the target cell. The handover command includes random access configuration information and second information, the second information being used to indicate a first moment. Before the first moment, an uplink synchronization process with the target cell is performed according to the random access configuration information; Based on the second information, at the first moment, an access procedure to the target cell is executed.

13. The method as described in claim 12, characterized in that, The method further includes: Before receiving the switching command, first information is sent, the first information indicating at least one of the following: The predicted measurement results for the first cell, which includes the target cell; or Predicted measurement events related to a first cell, which includes the target cell.

14. The method as described in claim 12 or 13, characterized in that, The handover command also includes the random access-free configuration information of the target cell, which includes configuration authorization (CG) configuration information and / or dynamic authorization (DG) configuration information.

15. The method as described in claim 14, characterized in that, Based on the second information, at the first moment, an access procedure to the target cell is executed, including: Based on the second information, at the first moment, access to the target cell is performed through a random access procedure.

16. The method as described in claim 14 or 15, characterized in that, Before the first moment, the uplink synchronization process with the target cell is performed according to the random access configuration information, including: Before the first moment, a preamble is sent according to the random access configuration information.

17. The method as described in claim 16, characterized in that, The method further includes: Receive a first message, which is used to respond to the preamble, and the first message carries a timing advance amount TA.

18. The method according to any one of claims 12 to 17, characterized in that, The second information is used to indicate timer information, which is used to determine the first time.

19. The method according to any one of claims 12 to 18, characterized in that, The method further includes: Upon receiving the switching command, a timer is started.

20. A switching method, characterized in that, include: A handover command is sent, which instructs the terminal device to hand over to the target cell. The handover command includes random access configuration information and second information. The second information is used to indicate a first moment. The random access configuration information is used to perform an uplink synchronization process with the target cell.

21. The method as described in claim 20, characterized in that, The method further includes: Before sending the switching command, first information is received, the first information indicating at least one of the following: The predicted measurement results for the first cell, which includes the target cell; or Predicted measurement events related to a first cell, which includes the target cell.

22. The method as described in claim 21, characterized in that, The method further includes: Based on the first information, the switching command is determined.

23. The method according to any one of claims 20 to 22, characterized in that, The handover command also includes: the random access-free configuration information of the target cell, which includes configuration authorization CG configuration information and / or dynamic authorization DG configuration information.

24. The method according to any one of claims 20 to 23, characterized in that, The second information is used to indicate timer information, which is used to determine the first time.

25. A communication device, characterized in that, include: Includes a module for performing the method as described in any one of claims 1 to 24.

26. A communication device, characterized in that, include: A processor, when invoked from a computer program in memory, causes the apparatus to perform the method as described in any one of claims 1 to 24.

27. A communication device, characterized in that, The device includes a processor and a transceiver, the transceiver being used to receive information from other communication devices besides the communication device and to output information to other communication devices besides the communication device, and the processor calling a computer program stored in memory to execute the method as described in any one of claims 1 to 24.

28. A computer-readable storage medium, characterized in that, Used to store a computer program, the computer program including instructions for implementing the method as described in any one of claims 1 to 24.

29. A computer program product, the computer program product comprising instructions, characterized in that, When the instructions are executed on a computer, the computer causes the computer to perform the method as described in any one of claims 1 to 24.

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