Wireless communication method, terminal device, and network device

Abstract

Provided are a wireless communication method, a terminal device, and a network device. The method comprises: a terminal device starts one or more first timers, wherein the first timer is used to indicate one or more of the following: a duration for which the terminal device waits to receive a first timing advance (TA) corresponding to one or more target network devices, the first TA being used by the terminal device for conditional handover; and a duration for which the terminal device waits to receive response information sent by a source network device, the response information being used by the source network device to respond to a measurement report sent by the terminal device. The terminal device starts the first timer, which helps to increase the probability of the terminal device receiving the TA of a target cell, thereby increasing the success rate of conditional handover.

Description

Wireless communication methods, terminal equipment and network equipment Technical Field

[0001] This application relates to the field of communication technology, and more specifically, to a wireless communication method, terminal device, and network device. Background Technology

[0002] In communication systems, terminal devices can obtain the timing advance (TA) of the target cell before performing conditional handover. However, there may be situations where the terminal device cannot obtain the TA of the target cell in time, affecting the conditional handover of the terminal device. Summary of the Invention

[0003] This application provides a wireless communication method, terminal device, and network device. The various aspects covered by this application are described below.

[0004] In a first aspect, a wireless communication method is provided, comprising: a terminal device activating one or more first timers, the first timers indicating one or more of the following: the duration for which the terminal device waits to receive a first timing advance (TA) corresponding to one or more target network devices, the first TA being used by the terminal device to perform condition switching; and the duration for which the terminal device waits to receive response information sent by a source network device, the response information being used by the source network device to respond to a measurement report sent by the terminal device.

[0005] In a second aspect, a wireless communication method is provided, comprising: a source network device receiving first information sent by a terminal device, the first information being used to indicate a measurement report; wherein, the sending of the first information is used to trigger the terminal device to start one or more first timers, the first timers being used to indicate one or more of the following: the duration for which the terminal device waits to receive a first timing advance (TA) corresponding to one or more target network devices, the first TA being used by the terminal device to perform a conditional switch; and the duration for which the terminal device waits to receive response information sent by the source network device, the response information being used by the source network device to respond to the measurement report sent by the terminal device.

[0006] Thirdly, a wireless communication method is provided, comprising: a target network device receiving second information sent by a terminal device, the second information being used to indicate a preamble; wherein, sending the second information is used to trigger the terminal device to start one or more first timers, the first timers being used to indicate the duration for which the terminal device waits to receive one or more first timing advances (TAs) corresponding to the target network device, the first TAs being used by the terminal device to perform condition switching.

[0007] Fourthly, a terminal device is provided, the terminal device comprising: a startup unit for starting one or more first timers, the first timers being used to indicate one or more of the following: the duration for which the terminal device waits to receive a first timing advance (TA) corresponding to one or more target network devices, the first TA being used by the terminal device to perform condition switching; the duration for which the terminal device waits to receive response information sent by a source network device, the response information being used by the source network device to respond to a measurement report sent by the terminal device.

[0008] Fifthly, a network device is provided, the network device being a source network device, the network device comprising: a receiving unit, configured to receive first information sent by a terminal device, the first information being used to indicate a measurement report; wherein, the sending of the first information is used to trigger the terminal device to start one or more first timers, the first timers being used to indicate one or more of the following: the duration for which the terminal device waits to receive a first timing advance (TA) corresponding to one or more target network devices, the first TA being used by the terminal device to perform condition switching; the duration for which the terminal device waits to receive response information sent by the source network device, the response information being used by the source network device to respond to the measurement report sent by the terminal device.

[0009] In a sixth aspect, a network device is provided, the network device being a target network device, the network device comprising: a receiving unit, configured to receive second information sent by a terminal device, the second information being used to indicate a preamble; wherein, the sending of the second information is used to trigger the terminal device to start one or more first timers, the first timers being used to indicate the duration for which the terminal device waits to receive one or more first timing advances (TAs) corresponding to the target network device, the first TAs being used by the terminal device to perform condition switching.

[0010] In a seventh aspect, a terminal device is provided, including a processor, a memory, and a communication interface, wherein the memory is used to store one or more computer programs, and the processor is used to invoke the computer programs in the memory to cause the terminal device to perform some or all of the steps in the method of the first aspect.

[0011] Eighthly, a network device is provided, including a processor, a memory, and a transceiver, wherein the memory is used to store one or more computer programs, and the processor is used to invoke the computer programs in the memory to cause the network device to perform some or all of the steps in the method of the second aspect.

[0012] A ninth aspect provides a network device including a processor, a memory, and a transceiver, wherein the memory is used to store one or more computer programs, and the processor is used to invoke the computer programs in the memory to cause the network device to perform some or all of the steps of the method of the third aspect.

[0013] Tenthly, embodiments of this application provide a communication system including the aforementioned terminal device and / or network device. In another possible design, the system may further include other devices that interact with the terminal device or network device as described in the embodiments of this application.

[0014] Eleventhly, embodiments of this application provide a computer-readable storage medium storing a computer program that causes a communication device (e.g., a terminal device or a network device) to perform some or all of the steps in the methods described above.

[0015] In a twelfth aspect, embodiments of this application provide a computer program product, wherein the computer program product includes a non-transitory computer-readable storage medium storing a computer program operable to cause a communication device (e.g., a terminal device or a network device) to perform some or all of the steps of the methods described in the foregoing aspects. In some implementations, the computer program product may be a software installation package.

[0016] In a thirteenth aspect, embodiments of this application provide a chip including a memory and a processor, the processor being able to call and run a computer program from the memory to implement some or all of the steps described in the methods of the foregoing aspects.

[0017] In this application, the terminal device starts one or more first timers. The first timers indicate the duration for which the terminal device waits to receive a first TA (Transmission Terminal) from one or more target network devices for conditional handover, and / or the duration for which the terminal device waits to receive a response to the measurement report from the source network device. Starting the first timers helps increase the probability of the terminal device receiving the TA from the target cell, thereby improving the success rate of conditional handover. Attached Figure Description

[0018] Figure 1 shows the wireless communication system 100 used in an embodiment of this application.

[0019] Figure 2 is a schematic diagram of a network architecture applicable to embodiments of this application.

[0020] Figures 3A and 3B are schematic diagrams of wireless protocol stack structures applicable to embodiments of this application.

[0021] Figure 4 is a schematic diagram of the condition switching process based on layer 1.

[0022] Figure 5 is an exemplary flowchart of how a terminal device obtains a TA in advance before the execution condition switch.

[0023] Figure 6 is a schematic flowchart of a wireless communication method according to an embodiment of this application.

[0024] Figure 7 is a schematic diagram of a terminal device according to an embodiment of this application.

[0025] Figure 8 is a schematic diagram of a network device according to an embodiment of this application.

[0026] Figure 9 is a schematic diagram of another network device according to an embodiment of this application.

[0027] Figure 10 is a schematic structural diagram of a communication device according to an embodiment of this application. Detailed Implementation

[0028] Communication system architecture

[0029] Figure 1 is a system architecture example diagram of a wireless communication system 100 to which embodiments of this application can be applied. The wireless communication system 100 may include a network device 110 and a terminal device 120. The network device 110 may be a device that communicates with the terminal device 120. The network device 110 may provide communication coverage for a specific geographical area and may communicate with the terminal device 120 located within that coverage area.

[0030] Figure 1 exemplarily illustrates a network device and multiple terminal devices, such as terminal devices 120a to 120j in Figure 1. Optionally, the wireless communication system 100 may include multiple network devices, and each network device may include other numbers of terminal devices within its coverage area; this application embodiment does not limit this.

[0031] Optionally, the wireless communication system 100 may also include other network entities such as a network controller and a mobility management entity, which is not limited in this embodiment.

[0032] It should be understood that the technical solutions of the embodiments of this application can be applied to various communication systems, such as: 5th-generation (5G) systems or new radio (NR) systems, long-term evolution (LTE) systems, LTE frequency division duplex (FDD) systems, LTE time division duplex (TDD) systems, advanced long-term evolution (LTE-A) systems, enhanced 5G (5G advanced) systems, etc. The technical solutions provided in this application can also be applied to future communication systems, such as 6th-generation (6G) mobile communication systems, satellite communication systems, etc.

[0033] The terminal device in this application embodiment can also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station (MS), mobile terminal (MT), remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user device. The terminal device in this application embodiment can be a device that provides voice and / or data connectivity to a user, and can be used to connect people, objects, and machines, such as a handheld device with wireless connectivity, vehicle-mounted device, etc. The terminal device in the embodiments of this application may be a mobile phone, tablet computer, laptop computer, handheld computer, camera equipment, mobile internet device (MID), wearable device, virtual reality (VR) device, augmented reality (AR) device, wireless terminal in industrial control, wireless terminal in self-driving, wireless terminal in remote medical surgery, wireless terminal in smart grid, wireless terminal in transportation safety, wireless terminal in smart city, wireless terminal in smart home, etc. Optionally, the terminal device may be used to act as a base station. For example, the terminal device may act as a scheduling entity, providing sidelink signals between UEs in vehicle-to-everything (V2X) or device-to-device (D2D) connections. For example, cellular phones and cars communicate with each other using sidelink signals. Cellular phones and smart home devices can communicate without relaying communication signals through base stations.

[0034] The network device in this application embodiment can be a device for communicating with terminal devices. This network device can also be called an access network device or a radio access network device, such as a base station (BS). In this application embodiment, the network device can refer to a radio access network (RAN) node or a next-generation RAN (NG-RAN) node (or device) that connects user equipment to a wireless network. A base station can broadly encompass, or be replaced by, various names including: NodeB, evolved NodeB (eNB), next-generation NodeB (gNB), relay station, transmitting and receiving point (TRP), transmitting point (TP), master station (MeNB), secondary station (SeNB), multi-mode radio (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (DU), positioning node, etc. A base station can be a macro base station, micro base station, relay node, donor node, or similar entities, or combinations thereof. A base station can also refer to a communication module, modem, or chip installed within the aforementioned equipment or apparatus. Base stations can also be mobile switching centers, devices that perform base station functions in D2D, V2X, and machine-to-machine (M2M) communications, network-side devices in 6G networks, and devices that perform base station functions in future communication systems. Base stations can support networks using the same or different access technologies. The embodiments of this application do not limit the specific technologies or device forms used in the network equipment.

[0035] Base stations can be fixed or mobile. For example, a helicopter or drone can be configured to act as a mobile base station, and one or more cells can move depending on the location of the mobile base station. In other examples, a helicopter or drone can be configured as a device to communicate with another base station.

[0036] In some deployments, the network device in this application embodiment may refer to a CU or a DU, or the network device may include both a CU and a DU. The gNB may also include an AAU.

[0037] Network devices and terminal devices 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 satellites. This application does not limit the scenario in which the network devices and terminal devices are located.

[0038] It should be understood that all or part of the functions of the communication device in this application can also be implemented by software functions running on hardware, or by virtualization functions instantiated on a platform (e.g., a cloud platform).

[0039] Figure 2 illustrates a schematic diagram of a network architecture 200 according to an embodiment of this application. This network architecture 200 describes the network architecture of a 5G NR / LTE / LTE-A system, which can also be referred to as a 5G system (5GS) / evolved packet system (EPS) network architecture. The network architecture 200 includes at least one of the following: network device 110, terminal device 120, 5G core network (5GC) / evolved packet core (EPC) 210, home subscriber server (HSS) / unified data management (UDM) 220, and Internet service 230. The network device and terminal device in Figure 2 are illustrated using RAN and UE as examples, respectively.

[0040] As shown in Figure 2, network device 110 provides user plane and control plane protocol termination to terminal device 120. Network device 110 is connected to 5GC / EPC 210 via an S1 / NG interface. 5GC / EPC 210 includes a mobility management entity (MME) / authentication management field (AMF) / session management function (SMF) 211, other MMEs / AMFs / SMFs 214, a service gateway (S-GW) / user plane function (UPF) 212, and a packet data network gateway (P-GW) / UPF 213. MME / AMF / SMF 211 is the control node that handles signaling between terminal device 120 and 5GC / EPC 210. Generally, MME / AMF / SMF 211 provides bearer and connection management. All user Internet Protocol (IP) packets are transmitted through the S-GW / UPF212, which is itself connected to the P-GW / UPF213. The P-GW provides UE IP address allocation and other functions. The P-GW / UPF213 is connected to Internet service 230. Internet service 230 includes operator-compliant Internet Protocol services, specifically including the Internet, intranet, IP multimedia subsystem (IMS), and packet-switched streaming services. It is evident that network architecture 200 provides packet-switched services; however, those skilled in the art will readily understand that the various concepts presented herein can be extended to networks providing circuit-switched services or other cellular networks.

[0041] Figures 3A and 3B respectively illustrate a schematic diagram of a wireless protocol stack structure according to an embodiment of this application. Figures 3A and 3B use a 5G wireless protocol stack as an example for illustration. The 5G wireless protocol stack is divided into two planes: the user plane (UP) protocol stack and the control plane (CP) protocol stack. The user plane protocol stack is the protocol suite used for user data transmission, and the control plane protocol stack is the protocol suite used for control signaling transmission in the 5G system. The specific names of each protocol stack layer are as follows:

[0042] As shown in Figure 3A, the user plane protocol stack includes, from top to bottom, the following layers: Service Data Adaptation Protocol (SDAP) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, and Physical (PHY) layer.

[0043] As shown in Figure 3B, the control plane protocol stack includes, from top to bottom: non-access stratum (NAS); radio resource control (RRC) layer, PDCP layer, RLC layer, MAC layer, and PHY layer.

[0044] It should be understood that the different layers in the above protocol stack have different functions, and they work together through inter-layer interaction to achieve communication between terminal devices and network devices. With the development of artificial intelligence technology, AI-assisted computing has permeated the processing implementation methods of the above protocol stack. For example, the scheduling algorithm of the MAC layer and the encoding / decoding algorithm of the PHY layer can apply artificial intelligence algorithms to improve the performance of communication algorithms.

[0045] As an example, the wireless protocol architecture shown in Figures 3A and 3B is applicable to the terminal device in this application.

[0046] As an example, the wireless protocol architecture shown in Figures 3A and 3B is applicable to the network device in this application.

[0047] It should be understood that the interpretation of the terminology in the embodiments of this application may refer to the TS36, TS37 and TS38 series of specifications of the 3rd generation partnership project (3GPP), but may also refer to the specifications of the Institute of Electrical and Electronics Engineers (IEEE).

[0048] Condition switching

[0049] To reduce handover latency, 3GPP introduced conditional handover. Initially, Layer 3-based conditional handover was introduced, where the terminal device (e.g., UE) determines whether a candidate cell meets pre-configured handover conditions based on Layer 3 measurements. If so, it initiates a handover automatically. However, because Layer 3 measurements require the terminal device to smooth the measured radio channel quality, and for high-frequency channels like frequency range (FR)2 where signal fluctuations are frequent, this smoothing process takes a considerable amount of time to initiate a Layer 3-based conditional handover. Therefore, 3GPP also introduced Layer 1-based conditional handover, where the terminal device initiates a handover automatically as long as the Layer 1 measurements of the candidate cell meet the pre-configured handover conditions.

[0050] For example, Figure 4 is a schematic diagram of the condition switching process based on Layer 1. The following describes the process of the terminal device performing condition switching based on the measurement results of Layer 1 with reference to Figure 4. Figure 4 includes steps S410 to S440.

[0051] In step S410, the source cell sends a Layer 1 conditional handover configuration to the terminal device.

[0052] Layer 1 conditional handover configuration includes the conditions for conditional handover and candidate cells (such as cell A).

[0053] In step S420, cell A sends a reference signal to the terminal device.

[0054] The terminal device receives the reference signal sent by cell A and performs layer 1 measurement.

[0055] In step S430, the terminal device determines whether the measurement result of layer 1 meets the conditions for condition switching.

[0056] Based on the Layer 1 measurement results obtained in step S420, the terminal device determines whether the conditions for conditional handover are met. If the terminal device determines that the Layer 1 measurement results corresponding to cell A meet the conditions for conditional handover, it proceeds to step S440.

[0057] In step S440, the terminal device accesses cell A.

[0058] In step S440 of Figure 4, the terminal device needs an uplink TA corresponding to cell A to access cell A. If not, the terminal device needs to initiate random access to cell A to obtain an uplink TA. Random access will consume some time and increase handover latency.

[0059] To address the aforementioned issues and further reduce handover latency, 3GPP introduced a procedure whereby the terminal device obtains its uplink TA in cell A before accessing cell A.

[0060] Since the uplink TA is only valid for a limited time, to ensure that the uplink TA is valid when the terminal device accesses cell A, the best approach is to acquire the TA a short period before the handover conditions are met. If the TA is acquired too early, the uplink TA will have already expired by the time the terminal device performs the handover.

[0061] For example, the source cell can configure pre-reporting conditions for the terminal device, such as a "pre-reporting channel condition threshold." If this condition is met, the terminal device reports a measurement report to the source cell. Upon receiving the report, the source cell instructs the terminal device to send a preamble to cell A, and simultaneously provides a non-contention preamble to the terminal device. After sending the preamble to cell A, the terminal device immediately returns to the source cell to transmit data. Upon receiving the preamble, cell A measures the TA and notifies the source cell. The source cell then notifies the terminal device of the TA through a medium access control element (MAC CE). Upon receiving this MAC CE, the terminal device starts a timer T1. Before timer T1 expires, the terminal device considers the TA valid. Subsequently, if the conditions for switching conditions are met, the terminal device uses this TA to access cell A without initiating random access.

[0062] The following describes an exemplary flowchart of how a terminal device obtains TA in advance, with reference to Figure 5, which includes steps S510 to S590.

[0063] In step S510, the source cell sends a Layer 1 conditional handover configuration to the terminal device.

[0064] Layer 1 conditional handover configuration includes the conditions for conditional handover, pre-reporting conditions, and candidate cells (such as cell A).

[0065] In step S520, cell A sends a reference signal to the terminal device.

[0066] The terminal device receives the reference signal sent by cell A and performs layer 1 measurement.

[0067] In step S530, the terminal device determines whether the measurement results of layer 1 meet the pre-reporting conditions.

[0068] Based on the Layer 1 measurement results obtained in step S520, the terminal device determines whether the pre-reporting conditions are met. If the terminal device determines that the Layer 1 measurement results meet the pre-reporting conditions, it proceeds to step S240.

[0069] In step S540, the terminal device sends a measurement report to the source cell.

[0070] The measurement report sent by the terminal device is determined based on the Layer 1 measurement results obtained in step S520. The measurement report indicates the channel quality of the source cell and / or candidate cell.

[0071] In step S550, the source cell instructs the terminal device to "send a preamble to cell A".

[0072] Once the source cell receives the measurement report, it sends an instruction message to the terminal device, instructing the terminal device to send a preamble to the cell.

[0073] In step S560, the terminal device sends a preamble to cell A.

[0074] After receiving the preamble, the terminal device sends the preamble to cell A.

[0075] In step S570, cell A sends a TA to the source cell.

[0076] After receiving the preamble from the terminal device, cell A measures the TA and sends the measured TA to the source cell.

[0077] In step S571, the source cell sends the TA corresponding to cell A to the terminal device.

[0078] The source cell receives the TA sent by cell A and forwards it to the terminal device via MAC CE. The terminal device receives the TA corresponding to cell A from the source cell and starts timer T1. Timer T1 is used to determine the validity period of the TA corresponding to cell A.

[0079] In step S580, the terminal device determines whether the layer 1 measurement result meets the conditions for condition switching.

[0080] During the operation of timer T1, the terminal device continues to perform layer 1 measurements and determines whether the layer 1 measurement results meet the conditions for condition switching. If the layer 1 measurement results meet the conditions for condition switching, then proceed to step S590.

[0081] In step S590, the terminal device accesses cell A.

[0082] It should be noted that in Figures 4 and 5 above, there is only one candidate cell, "Cell A". However, in the actual process, there can be multiple candidate cells for conditional handover. In some scenarios, the candidate cell is also referred to as the "target cell".

[0083] As discussed above, in a communication system, a terminal device can obtain the target cell's TA (Transmission Address) in advance before performing a conditional handover. However, there may be situations where the terminal device fails to obtain the target cell's TA in a timely manner, affecting the conditional handover process.

[0084] Taking the target cell's TA (Transmission Target) carried via MAC CE as an example, the target cell's TA can be transmitted from the source cell to the terminal device via MAC CE. However, since there is no feedback from the MAC CE, if the MAC CE fails to transmit over the air interface, the terminal device cannot obtain the target cell's TA in a timely manner. When the terminal device determines that the Layer 1 measurement result of the target cell meets the conditions for conditional handover, but has not obtained the target cell's TA, it cannot use the TA when accessing the target cell, which may lead to access failure.

[0085] To address the aforementioned issues, embodiments of this application provide a wireless communication method in which a terminal device initiates one or more first timers. These first timers indicate the duration for which the terminal device waits to receive a first TA (Transmission Terminal) from one or more target network devices for conditional handover, and / or the duration for which the terminal device waits to receive response information regarding a measurement report from a source network device. Initiating the first timers helps increase the probability of the terminal device receiving the TA from the target cell, thereby improving the success rate of conditional handover.

[0086] The wireless communication method of this application embodiment is described below with reference to FIG6. FIG6 is a schematic flowchart of the wireless communication method of this application embodiment. The method shown in FIG6 includes step S610.

[0087] In step S610, the terminal device starts one or more first timers.

[0088] The following section describes a scheme for a terminal device to start one or more first timers, in conjunction with Example 1.

[0089] Example 1: The terminal device starts one or more first timers.

[0090] In some implementations, the first timer is used to indicate the duration for which the terminal device waits to receive the first TA corresponding to one or more target network devices, and / or the duration for which the terminal device waits to receive the response information sent by the source network device. That is to say, during the operation of the first timer, the terminal device can receive the first TA corresponding to one or more target network devices, and / or the response information sent by the source network device.

[0091] In some implementations, the target network device can be understood as the network device of the target cell of the terminal device, or the network device of the candidate cell of the terminal device, or the network device of the alternative cell of the terminal device. For example, the target network device is the network device of cell A mentioned above. Another example is the base station corresponding to cell A mentioned above.

[0092] In some implementations, the source network device is the network device of the source cell of the terminal device. For example, the source network device can be the base station corresponding to the source cell of the terminal device.

[0093] In some implementations, the target cell for the terminal device is configured by the source network device. For example, the source network device indicates the target cell for the terminal device when sending conditional handover configuration.

[0094] In some implementations, the first TA is used for conditional handover by the terminal device, or in other words, the first TA is used for the terminal device to access the target cell corresponding to the first TA based on the conditional handover configuration.

[0095] For ease of description, the third information will be used below to indicate the first TA corresponding to one or more target network devices.

[0096] In some implementations, the third information is carried by the MAC CE.

[0097] In some implementations, the third information is carried on an existing MAC CE.

[0098] In some implementations, the third information is carried on a new MAC CE.

[0099] In some implementations, the new MAC CE uses a new logical channel identification (LCID) or a new (extended logical channel identification, eLCID) identifier.

[0100] In some implementations, due to sufficient downlink power, a new eLCID can be used to identify the MAC CE carrying third-party information instead of a new LCID.

[0101] In some implementations, a MAC CE carrying third-party information includes a first TA corresponding to a target cell network device.

[0102] In some implementations, a MAC CE carrying third-party information includes the first TA corresponding to the network devices of multiple target cells.

[0103] In some implementations, the MAC CE carrying the third information may not include the target cell information. For example, referring to Figure 5, in step S540, when the terminal device reports a measurement report of only one target cell to the network device of the source cell at a time, the terminal device assumes that the TA indicated by the third information sent by the source network device corresponds to this unique target cell.

[0104] In some implementations, the target cell information can be one or more of the following: the target cell's identity identifier (ID); the target cell's index; or the target cell's index carried in the conditional handover configuration.

[0105] In some implementations, the MAC CE carrying third information may include information about the target cell. For example, referring to Figure 5, in step S540, when the terminal device reports measurement reports of multiple target cells to the network device of the source cell, after receiving the MAC CE carrying third information from the source network device, since a MAC CE contains only the first TA corresponding to the network device of the target cell and information about the target cell, if the target cell information included in the MAC CE indicates that the target cell is the target cell associated with the measurement report reported by the terminal device itself, the terminal device considers the first TA included in the MAC CE to be the first TA of one of the multiple target cells it requested. For another example, the target cell information is the index of the target cell. Suppose that the terminal device reports measurement reports of cell A (index 00) and cell B (index 01) in step S540, and cell A and cell B are the target cells of the terminal device. Later, the terminal device receives a MAC CE carrying the third cell, and the MAC CE indicates the candidate cell with index 01, with the corresponding first TA being XXX. Then, the terminal device considers the TA it can use to access cell B to be XXX.

[0106] In some implementations, if a MAC CE carrying third-party information includes the first TA corresponding to the network devices of multiple target cells, then the MAC CE needs to include information about each target cell. For example, if the target cells of the terminal device include cell A, cell B, and cell C, and the MAC CE carrying third-party information includes the first TA corresponding to the network devices of cell A, cell B, and cell C, then the MAC CE needs to include the indexes of cell A, cell B, and cell C, or the IDs of cell A, cell B, and cell C.

[0107] In some implementations, the response information is used by the source network device to respond to the measurement report sent by the terminal device.

[0108] In some implementations, the measurement report can be a measurement report from radio resource management (RRM) measurements.

[0109] In this application embodiment, the method of obtaining the measurement report is not limited. In some implementations, the measurement report is the measurement result of Layer 1 measurement. In other implementations, the measurement report is the measurement result of Layer 3 measurement.

[0110] For ease of description, the first information will be used to indicate the measurement report, and the fourth information will be used to indicate the response information.

[0111] In some implementations, the reporting of the first information can be triggered based on a first condition. That is, after the terminal device determines that the measurement result meets the first condition, the terminal device reports the first information, which indicates that the measurement report meets the first condition.

[0112] In some implementations, the first condition is the pre-reporting condition mentioned above. The terminal device determines whether the measurement result meets the pre-reporting condition. If the pre-reporting condition is met, the terminal device reports the first information to the source network device. For example, referring to Figure 5, if the first condition is the pre-reporting condition carried in the Layer 1 condition handover configuration sent by the source cell to the terminal device in step S510, then in step S530, the terminal device determines whether the Layer 1 measurement result meets the pre-reporting condition. If it does, it proceeds to step S540 and sends the first information to the source cell. The first information indicates a measurement report that meets the pre-reporting condition.

[0113] In some implementations, the measurement report indicated by the first information corresponds to the measurement results of one or more target cells. Accordingly, after receiving the first information, the source network device assumes that one or more target cells corresponding to the measurement report need to obtain the first TA.

[0114] In some implementations, the measurement report indicated by the first information corresponds to the measurement result of the source cell. Accordingly, after receiving the first information, the source network device assumes that all target cells of the terminal device need to obtain the first TA.

[0115] In some implementations, the measurement report indicated by the first information does not correspond to the measurement results of any target cell, or corresponds to the measurement results of a target cell that has been configured. Accordingly, after receiving the first information, the source network device assumes that all target cells of the terminal device need to obtain the first TA.

[0116] In some implementations, the first information is carried in one or more of the following: physical uplink control channel (PUCCH); MAC CE; RRC message.

[0117] In some implementations, if the first information is carried on a PUCCH, then the resources of the PUCCH can be configured by the source network device.

[0118] In some implementations, the first information is also used to indicate the cell information to which one or more target network devices belong.

[0119] In some implementations, the information of the cell to which the target network device belongs can be understood as the information of the target cell.

[0120] In some implementations, the target cell information can be one or more of the following: the target cell's identity identifier (ID); the target cell's index; or the target cell's index carried in the conditional handover configuration.

[0121] In some implementations, if the measurement report indicates the measurement result of a target cell, the first information can indicate the cell information to which a target network device belongs. For example, if cell A is the target cell of the terminal device, and the first information indicates the measurement result of cell A, the first information can also indicate the index of cell A.

[0122] In some implementations, if the measurement report indicates measurement results for multiple target cells, the first information can indicate the cell information to which the multiple target network devices belong. For example, if cell A and cell B are target cells for the terminal device, and the first information indicates the measurement results for cell A and cell B, the first information can also indicate the indices of cell A and cell B.

[0123] In some implementations, if the first information is carried in a MAC CE, then the first information is carried in an existing MAC CE.

[0124] In some implementations, if the first information is carried in the MAC CE, then the first information is carried in the new MAC CE.

[0125] In some implementations, the new MAC CE uses a new LCID or a new eLCID identifier.

[0126] In some implementations, due to uplink power limitations, eLCID incurs additional overhead, so a new LCID can be used to identify the MAC CE carrying the first information.

[0127] In some implementations, if the first information is triggered based on pre-reporting conditions, the fourth information is used to instruct the terminal device to send a preamble to one or more target network devices.

[0128] In some implementations, the fourth information is also used to indicate the preamble that the terminal device sends to the target network device. For example, referring to Figure 5, in step S450, the source cell sends the fourth information to the terminal device (i.e., instructs the terminal device to send a preamble to cell A). The fourth information is also used to indicate the preamble, which is the preamble that the terminal device sends to the target network device of cell A in step S560.

[0129] In some implementations, the preamble indicated by the fourth information can be a non-contending preamble.

[0130] In some implementations, after the terminal device receives the fourth information, it sends second information to the target network device. The second information is used to indicate the preamble. For example, referring to Figure 5, in step S450, the source cell sends the fourth information to the terminal device (i.e., instructs the terminal device to send the preamble to cell A). The fourth information is also used to indicate the preamble. In step S560, the terminal device sends the second information to the target network device of cell A. The preamble indicated by the second information is the one indicated by the fourth information.

[0131] In some implementations, the fourth information is sent from the source network device to the terminal device before the terminal device receives the third information.

[0132] In some implementations, after receiving the fourth information, the terminal device sends the second information to the target network device. Upon receiving the second information, the target network device measures the first TA and sends the first TA back to the source network device. After receiving the first TA, the source network device sends the third information to the terminal device, indicating the first TA corresponding to the target network device. For example, referring to Figure 5, in step S450, the source cell sends the fourth information to the terminal device (i.e., instructing the terminal device to send a preamble to cell A). The fourth information also indicates the preamble. In step S560, the terminal device sends the second information to the target network device of cell A. The preamble indicated by the second information is the one indicated by the fourth information. In step S570, the network device of cell A sends its measured first TA to the source network device. After receiving the first TA, the network device of the source cell sends the third information to the terminal device via MAC CE in step S571. The third information indicates the first TA corresponding to the network device of cell A.

[0133] In some implementations, the first timer is used to indicate the duration for which the terminal device waits to receive the third information, and / or the duration for which the terminal device waits to receive the fourth information sent by the source network device. That is to say, during the operation of the first timer, the terminal device can receive the first TA corresponding to one or more target network devices, and receive the response information for the measurement report sent by the source network device.

[0134] In some implementations, the terminal device sends first information to the source network device before starting the first timer; that is, the terminal device starts the first timer after sending the first information to the source network device. For example, referring to Figure 5, in step S540, the terminal device sends first information to the source network device. The first information is used to indicate a measurement report. After completing step S540, the terminal device starts the first timer.

[0135] In some implementations, if the first timer is started after the terminal device sends the first information, then the first timer is used to indicate the duration for which the terminal device waits to receive the fourth information sent by the source network device. Correspondingly, after sending the fourth information, the source network device needs to ensure that the third information is successfully received by the terminal device. For example, referring to Figure 5, in step S540, the terminal device sends the first information to the source network device. The first information is used to indicate a measurement report. After completing step S540, the terminal device starts the first timer. The first timer is used to indicate that the terminal device waits to receive the fourth information in step S550, that is, to instruct the terminal device to send a preamble to cell A. Afterwards, the source network device ensures that the third information is successfully received by the terminal device.

[0136] In some implementations, if the first timer is started after the terminal device sends the first information, the first timer is used to indicate the duration for which the terminal device waits to receive the fourth information sent by the source network device, and / or the duration for which the terminal device waits to receive the third information. For example, referring to Figure 5, in step S540, the terminal device sends the first information to the source network device. The first information is used to indicate a measurement report. After completing step S540, the terminal device starts the first timer. The first timer is used to indicate the duration for which the terminal device waits to receive the fourth information in step S550 (such as instructing the terminal device to send a preamble to cell A) and the third information in step S571 (such as the duration for the TA corresponding to cell A).

[0137] In some implementations, before the terminal device starts the first timer, the terminal device sends second information to the target network device. The second information is used to indicate the preamble. That is, after the terminal device sends the second information to the target network device, the terminal device starts the first timer. For example, referring to Figure 5, in step S560, the terminal device sends a preamble to the source cell. After sending the preamble, the terminal device starts the first timer.

[0138] In some implementations, if the first timer is started after the terminal device sends the second information, then the first timer is used to indicate the duration for which the terminal device waits to receive the third information. For example, referring to Figure 5, in step S560, the terminal device sends a preamble to the target cell. After sending the preamble, the terminal device starts the first timer, which is used to indicate the duration for which the terminal device waits to receive the third information (such as the TA corresponding to cell A) in step S571.

[0139] In this embodiment of the application, the number of first timers started by the terminal device is not limited.

[0140] In some implementations, the terminal device starts a first timer for all target cells; this first timer can be called a common first timer. For example, if the terminal device has two target cells, cell A and cell B, then the terminal device can start a first timer to indicate the duration for which the terminal device waits to receive the first TA (Transmission Time) corresponding to the network devices in cell A and cell B.

[0141] In some implementations, the terminal device can start a first timer for each target cell, meaning that the first timer corresponds one-to-one with the target cell. For example, if the terminal device has two target cells, cell A and cell B, then the terminal device can start two first timers. The two first timers are used to indicate the duration for the terminal device to wait for the first TA corresponding to the network device in cell A, and the duration for the terminal device to wait for the first TA corresponding to the network device in cell B.

[0142] In some implementations, the target cells of the terminal device can be grouped, and a first timer can be started for each group. For example, if the terminal device has four target cells, namely cell A, cell B, cell C, and cell D, cell A and cell B constitute the first group, and cell C and cell D constitute the second group, the terminal device can start two first timers for the first group and the second group respectively.

[0143] In some implementations, target cells can be grouped based on the frequency band they belong to. For example, target cells of FR1 form the first group, and target cells of FR2 form the second group.

[0144] In some implementations, the target cells can be grouped based on the CU to which they belong. For example, the terminal device has four target cells, namely cell A, cell B, cell C, and cell D. Cell A and cell B belong to the first CU, cell C belongs to the second CU, and cell D belongs to the third group. The terminal device starts three first timers for the first CU, the second CU, and the third CU, respectively.

[0145] In some implementations, grouping can be based on whether the target cell and the source cell belong to the same CU. For example, if the source cell belongs to the first CU, and the terminal device has four target cells, namely cell A, cell B, cell C, and cell D, where cell A and cell B belong to the same CU as the source cell, and cell C and cell D do not belong to the same CU as the source cell, then the terminal device starts a first timer for cell A and cell B, and starts a timer for cell C and cell D.

[0146] In some implementations, the source network device can configure the target cell's packets.

[0147] In some implementations, the source network device configures the packet strategy for the target cell in a custom way.

[0148] In some implementations, the duration of the first timer is predefined or configured by the source network device. For example, the protocol defines the duration of the first timer. Alternatively, the source network device configures the duration of the first timer.

[0149] In some implementations, the duration of the first timer is carried in the conditional handover configuration sent by the source network device to the terminal device. For example, referring to Figure 5, in step S510, the source cell sends a conditional handover configuration to the terminal device. The conditional handover configuration may carry the duration of the first timer corresponding to multiple target cells, or the duration of the common first timer corresponding to multiple target cells.

[0150] In some implementations, the duration of the first timer varies. For example, if the terminal device targets 3 cells, it starts a timer for each target cell, resulting in a total of 3 first timers, each with a different duration.

[0151] In some implementations, the duration of different first timers can be the same. For example, if the terminal device targets 3 cells, it starts a first timer for each target cell, that is, it starts a total of 3 first timers, and the duration of the 3 first timers is the same.

[0152] In some implementations, the duration of the first timer corresponding to target cells belonging to the same frequency band is the same, while the duration of the first timer corresponding to target cells belonging to different frequency bands is different. For example, the duration of the first timer corresponding to a target cell belonging to FR1 is a first value, and the duration of the first timer corresponding to a target cell belonging to FR2 is a second value; the first value and the second value are different. As another example, the target cells of the terminal device include cell A, cell B, and cell C. Cells A and B belong to FR1, and cell C belongs to FR2. The terminal device starts one first timer for each of the three target cells, that is, it starts three first timers in total. The duration of the two first timers corresponding to cells A and B is the first value, and the duration of the first timer corresponding to cell C is the second value; the first value and the second value are different.

[0153] In some implementations, if the terminal device receives third information sent by the source network device during the first timer's operation, the terminal device stops the first timer.

[0154] In some implementations, if the terminal device starts multiple first timers, each corresponding to a target cell, and the first timer indicates the duration for which the terminal device waits to receive third information sent by the source network device, then during the operation of the first timer, if the terminal device receives third information sent by the source network device, and this third information is associated with one or more of the target cells corresponding to the multiple first timers, the terminal device stops all first timers. For example, if cell A and cell B are the target cells of the terminal device, first timer A is started by the terminal device for cell A, and first timer B is started by the terminal device for cell B, and both first timers A and B indicate the duration for which the terminal device waits to receive third information, then during the operation of both first timers, if the terminal device receives third information sent by the source network device, and this third information indicates the first TA corresponding to the network device of cell A, and the cell A associated with this third information is the same as the cell A corresponding to first timer A, then the terminal device stops first timers A and first timer B.

[0155] In some implementations, if the terminal device starts multiple first timers, each corresponding to a target cell, and the first timer indicates the duration for which the terminal device waits to receive third information sent by the source network device, then during the operation of the first timer, if the terminal device receives third information sent by the source network device, and the target cell associated with the third information is the same as the target cell corresponding to one of the multiple first timers, then the terminal device stops the first timer corresponding to the target cell associated with the third information. For example, if cell A and cell B are the target cells of the terminal device, first timer A is started by the terminal device for cell A, and first timer B is started by the terminal device for cell B, and both first timers A and B indicate the duration for which the terminal device waits to receive third information, then during the operation of the two first timers, if the terminal device receives third information sent by the source network device, and the third information indicates the first TA corresponding to the network device of cell A, and the cell A associated with the third information is the same as the cell A corresponding to first timer A, then the terminal device stops first timer A.

[0156] In some implementations, if the terminal device starts multiple first timers, each corresponding to a group of target cells, and the first timer indicates the duration for which the terminal device waits to receive third information sent by the source network device, then during the operation of the first timer, if the terminal device receives third information sent by the source network device, and this third information is associated with one or more of the target cells corresponding to the multiple first timers, the terminal device stops all first timers. For example, cells A, B, and C are the target cells of the terminal device, cells A and B form the first group, and cell C forms the second group. First timer A is started by the terminal device for the first group, and first timer B is started by the terminal device for the second group. Both first timers A and B indicate the duration for which the terminal device waits to receive third information. Then, during the operation of both first timers, if the terminal device receives third information sent by the source network device, and this third information indicates the first TA corresponding to the network device of cell A, and the cell A associated with this third information is one of the target cells corresponding to first timer A, then the terminal device stops both first timers A and first timer B.

[0157] In some implementations, if the terminal device starts multiple first timers, each corresponding to a group of target cells, and the first timer indicates the duration for which the terminal device waits to receive third information sent by the source network device, then during the operation of the first timer, if the terminal device receives third information sent by the source network device, and the target cell associated with the third information is part of a group of target cells corresponding to one of the multiple first timers, then the terminal device stops the first timer corresponding to the target cell associated with the third information. For example, cells A, B, and C are the target cells of the terminal device, cells A and B are the first group, and cell C is the second group. First timer A is started by the terminal device for the first group, and first timer B is started by the terminal device for the second group. Both first timers A and B are used to indicate the duration for which the terminal device waits to receive third information. Then, during the operation of the two first timers, if the terminal device receives third information sent by the source network device, and the third information indicates the first TA corresponding to the network device of cell A, and cell A associated with the third information is one of the target cells corresponding to first timer A, then the terminal device stops first timer A.

[0158] In some implementations, if the terminal device starts multiple first timers, each corresponding to a group of target cells, and the first timer indicates the duration for which the terminal device waits to receive third information sent by the source network device, then during the operation of the first timer, if the terminal device receives third information sent by the source network device, and the target cells associated with the third information are all in the group of target cells corresponding to one of the multiple first timers, then the terminal device stops the first timer corresponding to the target cells associated with the third information. For example, cells A, B, and C are the target cells of the terminal device, cells A and B are the first group, and cell C is the second group. First timer A is started by the terminal device for the first group, and first timer B is started by the terminal device for the second group. Both first timers A and B are used to indicate the duration for which the terminal device waits to receive third information. Then, during the operation of the two first timers, if the terminal device receives third information sent by the source network device, and the third information indicates the first TA corresponding to the network devices of cells A and B, and the cells A and B associated with the third information are all in the first group corresponding to first timer A, then the terminal device stops first timer A.

[0159] In some implementations, if the first timer is used to indicate the duration for which the terminal device waits to receive third information sent by the source network device, and the target cell associated with the third information received by the terminal device is all of the target cells in a group corresponding to one of the multiple first timers, the third information can be received by the terminal device at once. For example, cell A, cell B, and cell C are the target cells of the terminal device, cell A and cell B are the first group, cell C is the second group, first timer A is started by the terminal device for the first group, and first timer B is started by the terminal device for the second group. Both first timer A and first timer B are used to indicate the duration for which the terminal device waits to receive third information. Then, during the operation of the two first timers, if the terminal device receives a third information sent by the source network device, and the third information indicates the first TA corresponding to the network devices of cell A and cell B, and the cells A and B associated with the third information are all of the first group corresponding to first timer A, then the terminal device stops first timer A.

[0160] In some implementations, if the first timer is used to indicate the duration for which the terminal device waits to receive third information sent by the source network device, and the target cell associated with the third information received by the terminal device is all of the target cells in a group corresponding to one of the multiple first timers, the third information can be received by the terminal device in multiple sessions. For example, cell A, cell B, and cell C are the target cells of the terminal device, cell A and cell B are the first group, cell C is the second group, first timer A is started by the terminal device for the first group, and first timer B is started by the terminal device for the second group. Both first timer A and first timer B are used to indicate the duration for which the terminal device waits to receive third information. Then, during the operation of the two first timers, if the terminal device receives two pieces of third information sent by the source network device, the first piece of third information indicates the first TA corresponding to the network device of cell A, and the second piece of third information indicates the first TA corresponding to the network device of cell B, and the cells A and B associated with the two pieces of third information are all of the first group corresponding to first timer A, then the terminal device stops first timer A when it receives the second and third information.

[0161] In some implementations, if a terminal device starts a first timer, which corresponds to multiple target cells, and the first timer indicates the duration for which the terminal device waits to receive third information sent by the source network device, then during the operation of the first timer, if the terminal device receives third information sent by the source network device, and the target cell associated with the third information is one of the target cells corresponding to the first timer, then the terminal device stops the first timer. For example, if cell A and cell B are the target cells of the terminal device, and the first timer is started by the terminal device for cells A and B, and the first timer indicates the duration for which the terminal device waits to receive third information, then during the operation of the first timer, if the terminal device receives third information sent by the source network device, and the third information indicates the first TA corresponding to the network device of cell A, and cell A associated with the third information is one of the target network devices corresponding to the first timer, then the terminal device stops the first timer.

[0162] In some implementations, if a terminal device starts a first timer, which corresponds to multiple target cells, and the first timer indicates the duration for which the terminal device waits to receive third information sent by the source network device, then during the operation of the first timer, if the terminal device receives third information sent by the source network device, and the target cells associated with the third information include all target network devices corresponding to the first timer, then the terminal device stops the first timer. For example, if cell A and cell B are the target cells of the terminal device, and the first timer is started by the terminal device for cells A and B, and the first timer indicates the duration for which the terminal device waits to receive third information, then during the operation of the first timer, if the terminal device receives third information sent by the source network device, and the third information indicates the first TA corresponding to the network devices of cells A and B, and the cells A and B associated with the third information include all target network devices corresponding to the first timer, then the terminal device stops the first timer.

[0163] In some implementations, if the first timer is used to indicate the duration for which the terminal device waits to receive third information sent by the source network device, and the target cell associated with the third information received by the terminal device includes all target network devices corresponding to the first timer, the third information can be received by the terminal device at once. For example, if cell A and cell B are the target cells of the terminal device, and the first timer is started by the terminal device for cells A and B, and the first timer is used to indicate the duration for which the terminal device waits to receive third information, then during the operation of the first timer, if the terminal device receives a third message sent by the source network device, and the third message indicates the first TA corresponding to the network devices of cells A and B, and cells A and B associated with the third message are all target network devices corresponding to the first timer, then the terminal device stops the first timer.

[0164] In some implementations, if the first timer is used to indicate the duration for which the terminal device waits to receive third information sent by the source network device, and the target cells associated with the third information received by the terminal device include all target network devices corresponding to the first timer, the third information can be received by the terminal device in multiple sessions. For example, if cell A and cell B are the target cells of the terminal device, and the first timer is started by the terminal device for cells A and B, and the first timer is used to indicate the duration for which the terminal device waits to receive third information, then during the operation of the first timer, if the terminal device receives two pieces of third information sent by the source network device, the first piece of third information indicating the first TA corresponding to the network device of cell A, and the second piece of third information indicating the first TA corresponding to the network device of cell B, and cells A and B associated with the two pieces of third information are all target network devices corresponding to the first timer, then the terminal device stops the first timer.

[0165] In some implementations, if the terminal device receives the fourth information sent by the source network device during the first timer's operation, the terminal device stops the first timer.

[0166] In some implementations, if the terminal device starts multiple first timers, each corresponding to a target cell, and the first timers indicate the duration for which the terminal device waits to receive fourth information, then during the operation of the first timers, if the terminal device receives fourth information that is associated with one or more of the target cells corresponding to the multiple first timers, the terminal device stops all first timers. For example, if cell A and cell B are the target cells of the terminal device, first timer A is started by the terminal device for cell A, and first timer B is started by the terminal device for cell B, and both first timers A and B indicate the duration for which the terminal device waits to receive fourth information, then during the operation of the two first timers, if the terminal device receives fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cell A, and the cell A associated with the fourth information is the same as the cell A corresponding to first timer A, then the terminal device stops first timers A and first timer B.

[0167] In some implementations, if the terminal device starts multiple first timers, each corresponding to a target cell, and the first timer indicates the duration for which the terminal device waits to receive fourth information, then during the operation of the first timer, if the terminal device receives fourth information sent by the source network device, and the target cell associated with the fourth information is the same as the target cell corresponding to one of the multiple first timers, then the terminal device stops the first timer corresponding to the target cell associated with the fourth information. For example, if cell A and cell B are the target cells of the terminal device, first timer A is started by the terminal device for cell A, and first timer B is started by the terminal device for cell B, and both first timers A and B indicate the duration for which the terminal device waits to receive fourth information, then during the operation of the two first timers, if the terminal device receives fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cell A, and the cell A associated with the fourth information is the same as the cell A corresponding to first timer A, then the terminal device stops first timer A.

[0168] In some implementations, if the terminal device starts multiple first timers, each corresponding to a group of target cells, and the first timer indicates the duration for which the terminal device waits to receive fourth information sent by the source network device, then during the operation of the first timer, if the terminal device receives fourth information sent by the source network device, and the fourth information is associated with one or more of the target cells corresponding to the multiple first timers, the terminal device stops all first timers. For example, cells A, B, and C are the target cells of the terminal device, cells A and B are the first group, and cell C is the second group. First timer A is started by the terminal device for the first group, and first timer B is started by the terminal device for the second group. Both first timers A and B indicate the duration for which the terminal device waits to receive fourth information. Then, during the operation of the two first timers, if the terminal device receives fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cell A, and cell A associated with the fourth information is one of the target cells corresponding to first timer A, then the terminal device stops first timers A and first timer B.

[0169] In some implementations, if the terminal device starts multiple first timers, each corresponding to a group of target cells, and the first timer indicates the duration for which the terminal device waits to receive fourth information sent by the source network device, then during the operation of the first timer, if the terminal device receives fourth information sent by the source network device, and the target cell associated with the fourth information is part of a group of target cells corresponding to one of the multiple first timers, then the terminal device stops the first timer corresponding to the target cell associated with the fourth information. For example, cells A, B, and C are the target cells of the terminal device, cells A and B are the first group, and cell C is the second group. First timer A is started by the terminal device for the first group, and first timer B is started by the terminal device for the second group. Both first timers A and B indicate the duration for which the terminal device waits to receive fourth information. Then, during the operation of the two first timers, if the terminal device receives fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cell A, and cell A associated with the fourth information is one of the target cells corresponding to first timer A, then the terminal device stops first timer A.

[0170] In some implementations, if the terminal device starts multiple first timers, each corresponding to a group of target cells, and the first timer indicates the duration for which the terminal device waits to receive fourth information sent by the source network device, then during the operation of the first timer, if the terminal device receives fourth information sent by the source network device, and the target cells associated with the fourth information are all in the group of target cells corresponding to one of the multiple first timers, then the terminal device stops the first timer corresponding to the target cells associated with the fourth information. For example, cells A, B, and C are the target cells of the terminal device, cells A and B are the first group, and cell C is the second group. First timer A is started by the terminal device for the first group, and first timer B is started by the terminal device for the second group. Both first timers A and B indicate the duration for which the terminal device waits to receive fourth information. Then, during the operation of the two first timers, if the terminal device receives fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cells A and B, and the cells A and B associated with the fourth information are all in the first group corresponding to first timer A, then the terminal device stops first timer A.

[0171] In some implementations, if the first timer is used to indicate the duration for which the terminal device waits to receive the fourth information sent by the source network device, and the target cells associated with the fourth information received by the terminal device are all of the target cells in a group corresponding to one of the multiple first timers, the fourth information can be received by the terminal device at once. For example, cells A, B, and C are the target cells of the terminal device, cells A and B are the first group, and cell C is the second group. The first timer A is started by the terminal device for the first group, and the first timer B is started by the terminal device for the second group. Both the first timer A and the first timer B are used to indicate the duration for which the terminal device waits to receive the fourth information. Then, during the operation of the two first timers, if the terminal device receives a fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cells A and B, and the cells A and B associated with the fourth information are all of the first group corresponding to the first timer A, then the terminal device stops the first timer A.

[0172] In some implementations, if the first timer is used to indicate the duration for which the terminal device waits to receive the fourth information sent by the source network device, and the target cells associated with the fourth information received by the terminal device are all of the target cells in a group corresponding to one of the multiple first timers, the fourth information can be received by the terminal device in multiple sessions. For example, cells A, B, and C are the target cells of the terminal device, cells A and B are the first group, and cell C is the second group. The first timer A is started by the terminal device for the first group, and the first timer B is started by the terminal device for the second group. Both the first timer A and the first timer B are used to indicate the duration for which the terminal device waits to receive the fourth information. Then, during the operation of the two first timers, if the terminal device receives two fourth messages sent by the source network device, the first fourth message instructs the terminal device to send a preamble to cell A, and the second fourth message instructs the terminal device to send a preamble to cell B. The cells A and B associated with the two fourth messages are all of the first group corresponding to the first timer A. Then, when the terminal device receives the second fourth message, the terminal device stops the first timer A.

[0173] In some implementations, if a terminal device starts a first timer, which corresponds to multiple target cells and indicates the duration for which the terminal device waits to receive fourth information, then during the operation of the first timer, if the terminal device receives fourth information sent by the source network device, and the target cell associated with the fourth information is one of the target cells corresponding to the first timer, then the terminal device stops the first timer. For example, if cell A and cell B are the target cells of the terminal device, and the first timer is started by the terminal device for cells A and B, and the first timer indicates the duration for which the terminal device waits to receive fourth information, then during the operation of the first timer, if the terminal device receives fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cell A, and cell A associated with the fourth information is one of the target network devices corresponding to the first timer, then the terminal device stops the first timer.

[0174] In some implementations, if a terminal device starts a first timer, which corresponds to multiple target cells and indicates the duration for which the terminal device waits to receive fourth information, then during the operation of the first timer, if the terminal device receives fourth information sent by the source network device, and the target cells associated with the fourth information include all the target cells corresponding to the first timer, then the terminal device stops the first timer. For example, if cell A and cell B are the target cells of the terminal device, and the first timer is started by the terminal device for cells A and B, and the first timer indicates the duration for which the terminal device waits to receive fourth information, then during the operation of the first timer, if the terminal device receives fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cells A and B, and the cells A and B associated with the fourth information include all the target cells corresponding to the first timer, then the terminal device stops the first timer.

[0175] In some implementations, if the first timer is used to indicate the duration for which the terminal device waits to receive the fourth information sent by the source network device, and the target cells associated with the fourth information received by the terminal device include all target cells corresponding to the first timer, the fourth information can be received by the terminal device at once. For example, if cell A and cell B are the target cells of the terminal device, and the first timer is started by the terminal device for cell A and cell B, and the first timer is used to indicate the duration for which the terminal device waits to receive the fourth information, then during the operation of the first timer, if the terminal device receives a fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cell A and cell B, and cell A and cell B associated with the fourth information are all target network devices corresponding to the first timer, then the terminal device stops the first timer.

[0176] In some implementations, if the first timer is used to indicate the duration for which the terminal device waits to receive the fourth information sent by the source network device, and the target cells associated with the fourth information received by the terminal device include all target network devices corresponding to the first timer, the fourth information can be received by the terminal device in multiple installments. For example, if cell A and cell B are the target cells of the terminal device, and the first timer is started by the terminal device for cells A and B, and the first timer is used to indicate the duration for which the terminal device waits to receive the fourth information, then during the operation of the first timer, if the terminal device receives two fourth messages sent by the source network device, the first fourth message instructing the terminal device to send a preamble to cell A, and the second fourth message instructing the terminal device to send a preamble to cell B, and cells A and B associated with the two fourth messages are all target network devices corresponding to the first timer, then the terminal device stops the first timer.

[0177] In some implementations, if the first timer is used to indicate the duration for which the terminal device waits to receive the third and fourth information, then during the operation of the first timer, if the terminal device receives the third information sent by the source network device, the terminal device stops the first timer.

[0178] In some implementations, if the terminal device starts multiple first timers, each corresponding to a target cell, and the first timers indicate the duration for which the terminal device waits to receive third and fourth information, then during the operation of the first timers, if the terminal device receives third information that is associated with one or more of the target cells corresponding to the multiple first timers, the terminal device stops all first timers. For example, if cell A and cell B are the target cells of the terminal device, first timer A is started by the terminal device for cell A, and first timer B is started by the terminal device for cell B, and both first timers A and B indicate the duration for which the terminal device waits to receive third and fourth information, then during the operation of first timers A and B, if the terminal device first receives fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cell A, and after receiving the fourth information and sending the preamble to the target network device of cell A, and then receives third information sent by the source network device, and the third information indicates the first TA corresponding to the network device of cell A, and the cell A associated with the third information is the same as the cell A corresponding to first timer A, then the terminal device stops first timers A and first timer B.

[0179] In some implementations, if the terminal device starts multiple first timers, each corresponding to a target cell, and the first timers indicate the duration for which the terminal device waits to receive third and fourth information, then during the operation of the first timers, if the terminal device receives third information sent by the source network device, and the target cell associated with the third information is one of the target cells corresponding to the multiple first timers, then the terminal device stops the first timer corresponding to the target cell associated with the third information. For example, if cell A and cell B are the target cells of the terminal device, first timer A is started by the terminal device for cell A, and first timer B is started by the terminal device for cell B, and both first timers A and B indicate the duration for which the terminal device waits to receive third and fourth information, then during the operation of first timers A and B, if the terminal device first receives fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cell A, and after the terminal device sends the preamble to the target network device of cell A, it receives third information sent by the source network device, and the third information indicates the first TA corresponding to the network device of cell A, and the cell A associated with the third information is the same as the cell A corresponding to first timer A, then the terminal device stops first timer A.

[0180] In some implementations, if the terminal device starts multiple first timers, each first timer corresponds to a set of target cells, and the first timer is used to indicate the duration for the terminal device to wait to receive the third and fourth information sent by the source network device, during the operation of the first timer, if the terminal device receives the third information sent by the source network device, and the third information is associated with one or more of the target cells corresponding to the multiple first timers, then the terminal device stops all first timers. For example, cells A, B, and C are the target cells of the terminal device. Cells A and B are in the first group, and cell C is in the second group. The first timer A is started by the terminal device for the first group, and the first timer B is started by the terminal device for the second group. Both the first timer A and the first timer B are used to indicate the duration for the terminal device to wait to receive the third and fourth information. During the operation of the two first timers, if the terminal device receives the fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cell A, and after the terminal device sends the preamble to the network device of cell A, it receives the third information sent by the source network device. The third information instructs the first TA corresponding to the network device of cell A, and the cell A associated with the third information is one of the target cells corresponding to the first timer A, then the terminal device stops the first timer A and the first timer B.

[0181] In some implementations, if the terminal device starts multiple first timers, each first timer corresponding to a set of target cells, and the first timer is used to indicate the duration for the terminal device to wait to receive the third and fourth information sent by the source network device, then during the operation of the first timer, if the terminal device receives the third information sent by the source network device, and the target cell associated with the third information is part of a set of target cells corresponding to one of the multiple first timers, then the terminal device stops the first timer corresponding to the target cell associated with the third information. For example, cells A, B, and C are the target cells of the terminal device. Cells A and B are the first group, and cell C is the second group. The first timer A is started by the terminal device for the first group, and the first timer B is started by the terminal device for the second group. Both the first timer A and the first timer B are used to indicate the duration for the terminal device to wait to receive the fourth information. During the operation of the two first timers, if the terminal device receives the fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cell A, and after the terminal device sends the preamble to the network device of cell A, it receives the third information sent by the source network device. The third information instructs the first TA corresponding to the network device of cell A, and the cell A associated with the third information is one of the target cells corresponding to the first timer A, then the terminal device stops the first timer A.

[0182] In some implementations, if the terminal device starts multiple first timers, each first timer corresponding to a set of target cells, and the first timer is used to indicate the duration for the terminal device to wait to receive the third and fourth information sent by the source network device, then during the operation of the first timer, if the terminal device receives the third information sent by the source network device, and the target cell associated with the third information is all of the target cells in the set of target cells corresponding to one of the multiple first timers, then the terminal device stops the first timer corresponding to the target cell associated with the third information. For example, cells A, B, and C are the target cells of the terminal device. Cells A and B are in the first group, and cell C is in the second group. The first timer A is started by the terminal device for the first group, and the first timer B is started by the terminal device for the second group. Both the first timer A and the first timer B are used to indicate the duration for the terminal device to wait to receive the fourth information. During the operation of the two first timers, if the terminal device receives the fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cells A and B, and after the terminal device sends the preamble to the network devices of cells A and B, it receives the third information sent by the source network device. The third information instructs the first TA corresponding to the network devices of cells A and B, and the cells A and B associated with the third information are all in the first group corresponding to the first timer A, then the terminal device stops the first timer A.

[0183] In some implementations, if the first timer is used to indicate the duration for which the terminal device waits to receive the third and fourth information sent by the source network device, and the target cells associated with the third information received by the terminal device are all of the target cells in a group corresponding to one of the multiple first timers, then the third information can be received by the terminal device at once. For example, cells A, B, and C are the target cells of the terminal device, cells A and B are the first group, and cell C is the second group. The first timer A is started by the terminal device for the first group, and the first timer B is started by the terminal device for the second group. Both the first timer A and the first timer B are used to indicate the duration for which the terminal device waits to receive the fourth information. Then, during the operation of the two first timers, if the terminal device receives the fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cells A and B, and after the terminal device sends the preamble to the network devices of cells A and B, it receives a third information sent by the source network device. The third information instructs the first TA corresponding to the network devices of cells A and B, and the cells A and B associated with the third information are all of the first group corresponding to the first timer A, then the terminal device stops the first timer A.

[0184] In some implementations, if the first timer is used to indicate the duration for which the terminal device waits to receive the third and fourth information sent by the source network device, and the target cell associated with the third information received by the terminal device is all of the target cells in a group corresponding to one of the multiple first timers, then the third information can be received by the terminal device in multiple sessions. For example, cells A, B, and C are the target cells of the terminal device. Cells A and B are in the first group, and cell C is in the second group. The first timer A is started by the terminal device for the first group, and the first timer B is started by the terminal device for the second group. Both the first timer A and the first timer B are used to indicate the duration for the terminal device to wait to receive the fourth information. During the operation of the two first timers, if the terminal device receives the fourth information sent by the source network device, the fourth information instructs the terminal device to send a preamble to cells A and B. After the terminal device sends the preamble to the network devices of cells A and B, it receives two third information sent by the source network device. The first third information indicates the first TA corresponding to the network device of cell A, and the second third information indicates the first TA corresponding to the network device of cell B. The cells A and B associated with the two third information are all in the first group corresponding to the first timer A. When the second third information is received, the terminal device stops the first timer A.

[0185] In some implementations, if a terminal device starts a first timer, which corresponds to multiple target cells, and the first timer indicates the duration for which the terminal device waits to receive third and fourth information, then during the operation of the first timer, if the terminal device receives third information sent by the source network device, and the target cell associated with the third information is part of the target cells corresponding to the first timer, then the terminal device stops the first timer. For example, if cell A and cell B are the target cells of the terminal device, and the first timer is started by the terminal device for cells A and B, and the first timer indicates the duration for which the terminal device waits to receive third and fourth information, then during the operation of the first timer, if the terminal device first receives fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cell A, and after the terminal device sends the preamble to the network device of cell A, it then receives third information sent by the source network device, and the third information instructs the first TA corresponding to the network device of cell A, and cell A associated with the third information is part of the target cells corresponding to the first timer, then the terminal device stops the first timer.

[0186] In some implementations, if a terminal device starts a first timer, which corresponds to multiple target cells and indicates the duration for which the terminal device waits to receive third and fourth information, then during the operation of the first timer, if the terminal device receives third information sent by the source network device, and the target cells associated with the third information include all target cells corresponding to the first timer, then the terminal device stops the first timer. For example, if cell A and cell B are the target cells of the terminal device, and the first timer is started by the terminal device for cells A and B, and indicates the duration for which the terminal device waits to receive third and fourth information, then during the operation of the first timer, if the terminal device first receives fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cells A and B, and after the terminal device sends the preamble to the network devices of cells A and B, it then receives third information sent by the source network device, and the third information instructs the first TA (Target A) of the network devices of cells A and B, and the cells A and B associated with the third information include all target cells corresponding to the first timer, then the terminal device stops the first timer.

[0187] In some implementations, if the first timer is used to indicate the duration for which the terminal device waits to receive the third and fourth information sent by the source network device, and the target cells associated with the third information received by the terminal device include all target cells corresponding to the first timer, then the terminal device stops the first timer, and the third information can be received by the terminal device in one go. For example, if cell A and cell B are the target cells of the terminal device, and the first timer is started by the terminal device for cell A and cell B, and the first timer is used to indicate the duration for which the terminal device waits to receive the third and fourth information, then during the operation of the first timer, if the terminal device first receives the fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cell A and cell B, and after the terminal device sends the preamble to the network devices of cell A and cell B, it receives a third information sent by the source network device, and the third information instructs the first TA corresponding to the network devices of cell A and cell B, and the cells A and B associated with the third information include all target cells corresponding to the first timer, then the terminal device stops the first timer.

[0188] In some implementations, if the first timer is used to indicate the duration for which the terminal device waits to receive the third and fourth information sent by the source network device, and the target cells associated with the third information received by the terminal device are all of the target cells in a group corresponding to one of the multiple first timers, then the third information can be received by the terminal device in multiple sessions. For example, if cell A and cell B are the target cells of the terminal device, and the first timer is started by the terminal device for cell A and cell B, and the first timer is used to indicate the duration for which the terminal device waits to receive the third and fourth information, then during the operation of the first timer, if the terminal device first receives the fourth information sent by the source network device, and the fourth information instructs the terminal device to send a preamble to cell A and cell B, and after the terminal device sends the preamble to the network devices of cell A and cell B, it then receives two third messages sent by the source network device. The first third message indicates the first TA corresponding to the network device of cell A, and the second third message indicates the first TA corresponding to the network device of cell B. Furthermore, the cells A and B associated with the two third messages include all the target cells corresponding to the first timer. Therefore, when the second third message is received, the terminal device stops the first timer.

[0189] In some implementations, if the first timer expires, the terminal device sends the first information to the source network device, or requests again to obtain the TA between itself and the target cell.

[0190] In some implementations, if the first timer is used to indicate the duration for which the terminal device waits to receive third information sent by the source network device, a timeout of the first timer can be understood as the terminal device not receiving the third information during the first timer's operation, or the target cell associated with the received third information not meeting the aforementioned conditions for stopping the first timer. For example, cell A and cell B are the target cells of the terminal device, and the first timer is started by the terminal device for cells A and B. The condition for stopping the first timer is: during the first timer's operation, if the target cells associated with the third information received by the terminal device include all target cells corresponding to the first timer. If, during the first timer's operation, the third information received by the terminal device only indicates the first TA corresponding to the network device of cell A, then the first timer times out.

[0191] In some implementations, if the first timer is used to indicate the duration for which the terminal device waits to receive the fourth information sent by the source network device, a timeout of the first timer can be understood as the terminal device not receiving the fourth information during the first timer's operation, or the target cell associated with the received fourth information not meeting the aforementioned conditions for stopping the first timer. For example, cell A and cell B are the target cells of the terminal device, and the first timer is started by the terminal device for cells A and B. The condition for stopping the first timer is: during the first timer's operation, if the target cells associated with the fourth information received by the terminal device include all target cells corresponding to the first timer. If, during the first timer's operation, the fourth information received by the terminal device only indicates that the terminal device sends a preamble to cell A, then the first timer times out.

[0192] In some implementations, if the first timer is used to indicate the duration for which the terminal device waits to receive the third and fourth information sent by the source network device, a timeout of the first timer can be understood as the terminal device not receiving the third and fourth information during the first timer's operation, or the target cell associated with the received third information not meeting the aforementioned conditions for stopping the first timer. For example, cell A and cell B are the target cells of the terminal device, and the first timer is started by the terminal device for cell A and cell B. The condition for stopping the first timer is: during the first timer's operation, if the target cells associated with the third information received by the terminal device include all target cells corresponding to the first timer. If, during the first timer's operation, the fourth information received by the terminal device instructs the terminal device to send a preamble to cell A and cell B, and the terminal device sends the preamble to the network devices of cell A and cell B respectively, but only receives the first TA corresponding to the network device of cell A, then the first timer times out.

[0193] In some implementations, the measurement report indicated by the first information sent after the first timer expires can be a measurement report obtained before the first timer starts, or a measurement report obtained by the terminal device after the first timer expires.

[0194] In some implementations, the first timer corresponds to a target cell. After the first timer expires, the measurement report indicated by the first information sent by the terminal device to the source network device is associated with the target cell corresponding to the first timer. For example, if cell A is the target cell of the terminal device, the terminal device starts the first timer for cell A. If the first timer expires, the measurement report indicated by the first information sent by the terminal device to the source network device is associated with cell A.

[0195] In some implementations, the first timer corresponds to multiple target cells or a group of target cells. After the first timer expires, the measurement report indicated by the first information sent by the terminal device to the source network device is associated with all or part of the multiple target cells or a group of target cells corresponding to the first timer.

[0196] In some implementations, if the terminal device does not receive the third and / or fourth information during the first timer's operation, then after the first timer expires, the target cell associated with the measurement report indicated by the first information sent by the terminal device to the source network device can be any of the multiple target cells or a group of target cells corresponding to the first timer.

[0197] In some implementations, if the terminal device receives third and / or fourth information during the first timer's operation, the target cell associated with the measurement report indicated by the first information sent by the terminal device to the source network device after the first timer expires can be a target cell not associated with the third and / or fourth information received by the terminal device among multiple target cells or a group of target cells corresponding to the first timer during the first timer's operation. For example, if the first timer corresponds to cell A and cell B, the terminal device will stop the first timer after receiving the first TA corresponding to the network device of either cell A or cell B. Assuming that the terminal device does not receive the first TA corresponding to the network device of cell A or cell B during the first timer's operation, the measurement report indicated by the first information sent by the terminal device to the source network device after the first timer expires will be associated with both cell A and cell B. As another example, if the first timer corresponds to cell A and cell B, the terminal device will stop the first timer after receiving the first TA corresponding to the network devices of both cell A and cell B. Assuming that the terminal device received the first TA corresponding to the network device of cell A during the first timer's operation, the measurement report indicated by the first information sent by the terminal device to the source network device after the first timer expires can be associated only with cell B.

[0198] In some implementations, if the first timer expires and the first condition is met, the terminal device sends the first information to the source network device, or requests again to obtain the TA between itself and the target cell. That is to say, if the first timer expires and the result measured by the terminal device still meets the first condition, the terminal device sends the first information to the source network device, or requests again to obtain the TA between itself and the target cell.

[0199] In some implementations, the first timer corresponds to a target cell. After the first timer expires, the terminal device measures the target cell corresponding to the first timer. If the measurement result meets the first condition, the terminal device sends the first information to the source network device. The measurement report indicated by the first information is associated with the target cell corresponding to the first timer.

[0200] In some implementations, the first timer corresponds to multiple target cells or a group of target cells. After the first timer expires, the terminal device measures all or part of the multiple target cells or a group of target cells corresponding to the first timer. If all or part of them meet the first condition, the terminal device sends the first information to the source network device. The measurement report indicated by the first information is associated with the target cells whose measurement results meet the first condition.

[0201] In some implementations, if the terminal device does not receive the third and / or fourth information during the first timer's operation, then after the first timer expires, the target cell measured by the terminal device can be any of the multiple target cells or a group of target cells corresponding to the first timer.

[0202] In some implementations, if the terminal device receives third and / or fourth information during the first timer's operation, the target cell measured by the terminal device after the first timer expires can be a target cell among the multiple target cells or a group of target cells corresponding to the first timer during its operation, but not associated with the third and / or fourth information received by the terminal device. For example, if the first timer corresponds to cells A and B, the terminal device will stop the first timer after receiving the first TA corresponding to the network device of either cell A or cell B. If, during the first timer's operation, the terminal device does not receive the first TA corresponding to the network device of cell A or cell B, then after the first timer expires, the terminal device can measure both cells A and B. As another example, if the first timer corresponds to cells A and B, the terminal device will stop the first timer after receiving the first TA corresponding to the network devices of both cells A and B. If, during the first timer's operation, the terminal device only receives the first TA corresponding to the network device of cell A, then after the first timer expires, the terminal device can measure only cell B.

[0203] In some implementations, after the first timer expires, the target cell associated with the measurement report sent by the terminal device can be a target cell among the target cells that meets the first condition. For example, the first timer corresponds to cells A and B. After receiving the first TA corresponding to the network device of either cell A or cell B, the terminal device will stop the first timer. Assuming that the terminal device does not receive the first TA corresponding to the network device of cell A or cell B during the operation of the first timer, the terminal device can measure cells A and B after the first timer expires. If the measurement results of cells A and / or cell B meet the first condition, the terminal device will send first information to the source network device. The measurement report indicated by the first information is associated with cells A and / or cell B. As another example, the first timer corresponds to cells A and B. After receiving the first TA corresponding to the network devices of cells A and B, the terminal device will stop the first timer. Assuming that the terminal device receives the first TA corresponding to the network device of cell A during the operation of the first timer, the terminal device can measure only cell B after the first timer expires. If the measurement result of cell B meets the first condition, the terminal device will send first information to the source network device. The measurement report indicated by the first information is associated with cell B.

[0204] In some implementations, if the first timer times out and the first condition is not met, the terminal device does not send the first information to the source network device. That is to say, if the first timer times out and the result measured by the terminal device no longer meets the first condition, the terminal device does not send the first information to the source network device.

[0205] In some implementations, the first timer corresponds to a target cell. After the first timer expires, the terminal device measures the target cell corresponding to the first timer. If the measurement result does not meet the first condition, the terminal device does not send the first information to the source network device.

[0206] In some implementations, the first timer corresponds to multiple target cells or a group of target cells. After the first timer expires, the terminal device measures all or part of the multiple target cells or the group of target cells corresponding to the first timer. If all or part of the measured target cells meet a first condition, the terminal device sends first information to the source network device. For example, the first timer corresponds to all target cells of the terminal device, including cell A, cell B, and cell C. After receiving the first TA corresponding to the network device of any one of cells A, B, and C, the terminal device stops the first timer. Assuming that during the operation of the first timer, the terminal device does not receive the first TA corresponding to the network device of any one of the three cells, after the first timer expires, the terminal device can measure cells A, B, and C. If the measurement results of cells A and B do not meet the first condition, but the measurement result of cell C meets the first condition, the terminal device sends the first information to the source network device. The measurement report indicated by the first information is associated with cell C. As another example, the first timer corresponds to a group of target cells of the terminal device, including cells A, B, and C. After receiving the first TA corresponding to the network devices of cells A, B, and C, the terminal device stops the first timer. Assuming that during the first timer operation, the terminal device only receives the first TA corresponding to the network device of cell A, then after the first timer expires, the terminal device can measure cells B and C. If the measurement results of cells B and C both meet the first condition, the terminal device sends the first information to the source network device. The measurement report indicated by the first information is associated with cells B and C.

[0207] In some implementations, the first timer corresponds to multiple target cells or a group of target cells. After the first timer expires, the terminal device measures all or part of the multiple target cells or the group of target cells corresponding to the first timer. If all the measured target cells do not meet the first condition, the terminal device does not send the first information to the source network device. For example, if the first timer corresponds to cell A and cell B, the terminal device will stop the first timer after receiving the first TA corresponding to the network device of either cell A or cell B. Assuming that the terminal device does not receive the first TA corresponding to the network device of cell A or cell B during the operation of the first timer, the terminal device can measure cell A and cell B after the first timer expires. If the measurement results of cell A and cell B do not meet the first condition, the terminal device will not send the first information to the source network device. For example, the first timer corresponds to cell A and cell B. After the terminal device receives the first TA corresponding to the network device of cell A and cell B, it will stop the first timer. Assuming that the terminal device receives the first TA corresponding to the network device of cell A during the operation of the first timer, the terminal device can measure only cell B after the first timer expires. If the measurement result of cell B does not meet the first condition, the terminal device will not send the first information to the source network device.

[0208] In some implementations, if the terminal device sends the first information to the source network device after the first timer expires, the terminal device can start the first timer. The target cell corresponding to the newly started first timer is the same as the target cell corresponding to the first information. The first timer is used to indicate the duration for which the terminal device waits to receive the fourth information, or the duration for which it waits to receive the third and fourth information.

[0209] In some implementations, if the terminal device sends the first information to the source network device after the first timer expires, and after receiving the fourth information in response to the first information, the terminal device can start the first timer. The target cell corresponding to the newly started first timer is the same as the target cell corresponding to the first information. The first timer is used to indicate the duration for which the terminal device waits to receive the third information.

[0210] As can be seen from the above, the transmission of the first information can be triggered based on the first condition. In some scenarios, the first condition is carried in the condition switching configuration sent from the source network device to the terminal device. How to reduce the resources for transmitting the first condition is an urgent problem to be solved.

[0211] To address this issue, embodiments of this application also provide a wireless communication method in which a first condition for triggering the transmission of first information is associated with a condition switching configuration and / or a first offset value of the terminal device. Therefore, the source network device does not need to send the first condition to the terminal device; it only needs to send the condition switching configuration and / or information indicating the first offset value. The terminal device can then determine the first condition, which helps reduce transmission overhead.

[0212] The following example, exemplified by Example 2, illustrates the relationship between the first condition and the condition switching configuration of the terminal device.

[0213] Example 2: Conditional switching configuration and / or first offset value of the first condition associated terminal device.

[0214] In some implementations, the conditional handover configuration of the terminal device indicates the conditions for conditional handover. For example, the conditional handover configuration indicates that the condition for conditional handover is "the difference between the measurement signal quality of the target cell and the measurement signal quality of the source cell is higher than the relative threshold A".

[0215] In some implementations, the first offset value is used to indicate the offset between the trigger threshold of the measurement report and the conditional handover threshold indicated by the conditional handover configuration. Therefore, the trigger threshold of the measurement report can be determined based on the conditional handover threshold indicated by the conditional handover configuration and the first offset value. For example, if the conditional handover condition indicated by the conditional handover configuration is "the difference between the measurement signal quality of the target cell and the measurement signal quality of the source cell is higher than the relative threshold A", and the conditional handover threshold is the relative threshold A, then the trigger threshold of the measurement report, i.e., the trigger threshold of the first information, can be determined based on the relative threshold A and the first offset value.

[0216] In some implementations, the first condition is associated with the conditional handover configuration and the first offset value. This can be understood as the first condition being associated with the conditional handover threshold and the first offset value. Therefore, the first condition can be used to indicate that the channel quality measured by the terminal device satisfies "the threshold in the conditional handover condition + the first offset value". For example, if the conditional handover condition is "the difference between the measured signal quality of the target cell and the measured signal quality of the source cell is higher than the relative threshold A", then the first condition is associated with the relative threshold A and the first offset value. This first condition can be used to indicate that "the difference between the measured signal quality of the target cell and the measured signal quality of the source cell is higher than the sum of the relative threshold A and the first offset value". In other words, if the difference between the measured signal quality of the target cell and the measured signal quality of the source cell measured by the terminal device is higher than the sum of the relative threshold A and the first offset value, then the terminal device can send first information to the source network device.

[0217] It should be noted that the above only lists one condition for condition switching. In practice, a condition switching configuration can indicate one or more conditions for condition switching, and therefore there can be one or more first conditions, and thus one or more first offset values.

[0218] In some implementations, a first condition can correspond to one or more first offset values. For example, the condition for the terminal device to switch the first condition is "the difference between the measurement signal quality of the target cell and the measurement signal quality of the source cell is higher than the relative threshold A", and the condition for the terminal device to switch the second condition is "the measurement signal quality of the target cell is higher than the absolute threshold B, and the measurement signal quality of the source cell is lower than the absolute threshold C". There can be two first conditions, which are respectively associated with the conditions for switching the first condition and the conditions for switching the second condition. The two first conditions are associated with one or two first offset values. For example, the first condition 1 associated with the first condition handover can be associated with a first offset value 1, that is, the first condition 1 is "the difference between the measurement signal quality of the target cell and the measurement signal quality of the source cell is higher than the sum of the relative threshold A and the first offset value 1"; the first condition 2 associated with the second condition handover can be associated with a first offset value 2, that is, the first condition 2 is "the measurement signal quality of the target cell is higher than the sum of the absolute threshold B and the first offset value 2, and the measurement signal quality of the source cell is lower than the sum of the absolute threshold C and the first offset value 2", or the second condition 2 can be associated with a first offset value 2 and a second offset value 3, that is, the second condition 2 is "the measurement signal quality of the target cell is higher than the sum of the absolute threshold B and the first offset value 2, and the measurement signal quality of the source cell is lower than the sum of the absolute threshold C and the first offset value 3".

[0219] In some implementations, multiple first conditions can correspond to a single offset value. For example, the first condition switching condition of the terminal device is "the difference between the measurement signal quality of the target cell and the measurement signal quality of the source cell is higher than the relative threshold A," and the second condition switching condition of the terminal device is "the measurement signal quality of the target cell is higher than the absolute threshold B, and the measurement signal quality of the source cell is lower than the absolute threshold C." There can be two first conditions, which are respectively associated with the first condition switching condition and the second condition switching condition. The two first conditions are associated with one first offset value. For example, the first condition 1 associated with the first condition switching condition can be associated with a first offset value 1, that is, the first condition 1 is "the difference between the measurement signal quality of the target cell and the measurement signal quality of the source cell is higher than the sum of the relative threshold A and the first offset value 1"; the first condition 2 associated with the second condition switching condition can also be associated with a first offset value 1, that is, the first condition 2 is "the measurement signal quality of the target cell is higher than the sum of the absolute threshold B and the first offset value 1, and the measurement signal quality of the source cell is lower than the sum of the absolute threshold C and the first offset value 1."

[0220] In some implementations, the first offset value for the first condition is the same for multiple target cells, meaning that multiple target cells share the same first offset value for the same first condition. For example, regardless of whether the target cell belongs to FR1 or FR2, the same first offset value is used for the same first condition, or regardless of the CU to which the target cell belongs, the same first offset value is used for the same first condition.

[0221] In some other implementations, the first offset value associated with the first condition for target cells belonging to the same group is the same, while the first offset value associated with the first condition for target cells belonging to different groups is different.

[0222] In some implementations, target cells can be grouped according to the CU to which they belong. That is, the first offset value can be determined based on the CU to which the target network device belongs. For example, target cells belonging to the first CU are in the first group, and target cells belonging to the second CU are in the second group. All target cells in the first group are associated with the same first condition and the first offset value 1. All target cells in the second group are associated with the same first condition and the first offset value 2. The first offset value 1 and the second offset value 2 are different.

[0223] In some implementations, target cells can be grouped according to the frequency band to which they belong. That is, the first offset value can be determined based on the frequency band corresponding to the target network device. For example, the target cells of FR1 are in the first group, and the target cells of FR2 are in the second group. All target cells in the first group are associated with the same first condition and the first offset value 1. All target cells in the second group are associated with the same first condition and the first offset value 2. The first offset value 1 and the second offset value 2 are different.

[0224] In some implementations, the first offset value can be determined based on whether the CU to which the source network device belongs is the same as the CU to which the target network device belongs. In other words, the first offset value can be determined based on whether the source cell and the target cell belong to the same CU.

[0225] In some implementations, if the CU to which the source network device belongs is the same as the CU to which the target network device belongs, the first offset value of the first condition associated with the target cell to which the target network device belongs is set to a smaller value; otherwise, the first offset value of the first condition associated with the target cell to which the target network device belongs is set to a larger value. For example, if the target cell and the source cell are in the same CU, within the same CU, the target cell can quickly notify the source cell after measuring the TA. Therefore, for the source cell, TA acquisition is relatively fast, and the first offset value can be set relatively small. In this way, the terminal device will notify the source cell when the actual handover occurs very close to the time when the conditional handover occurs, thereby obtaining the TA value of the terminal device in the target cell, which can improve the accuracy of the TA value. If the target cell and the source cell are in different CUs, the time taken for the target cell to notify the source cell after measuring the TA is relatively long between different CUs. Therefore, for the source cell, TA acquisition is relatively slow, and the first offset value can be set relatively large. In this way, the terminal device will notify the source cell when the actual handover occurs relatively far from the time when the conditional handover occurs, thereby obtaining the TA value of the terminal device in the target cell, which can ensure that the TA value can be obtained before the actual handover occurs.

[0226] In some implementations, the first offset value can be predefined and / or configured by the source network device. For example, the first offset value may be specified by the protocol. Or, for example, if the source network device is a base station, the first offset value may be configured by the base station.

[0227] In some implementations, the first offset value can be configured by the source network device via an RRC message.

[0228] In some implementations, before the terminal device sends the first information, the network device sends a sixth piece of information to the terminal device. The sixth piece of information is used to indicate the conditional switching configuration of the terminal device; a first offset value; a target network device belonging to the same CU as the source network device; and a target network device not belonging to the same CU as the source network device.

[0229] In some implementations, the sixth information indicates the first offset value. For example, referring to Figure 5, before step 520, the network device sends the sixth information to the terminal device, which indicates the first offset value, so that the terminal device can determine in S530 whether the Layer 1 measurement result meets the first condition. Accordingly, upon receiving the sixth information, the terminal device can determine the first offset value associated with the first condition corresponding to the target cell.

[0230] In some implementations, the sixth information displays the condition switching configuration and the first offset value of the terminal device. For example, referring to Figure 5, the sixth information is the message carrying the condition switching configuration in step S510, and the sixth information may also indicate the first offset value. Using the first offset value instead of indicating the first condition in the message carrying the condition switching configuration helps reduce the overhead of the message carrying the condition switching configuration.

[0231] In some implementations, if the first offset value is determined based on whether the CU to which the source network device belongs is the same as the CU to which the target network device belongs, then the terminal device, upon receiving the sixth information, can determine whether the target cell and the source cell belong to the same CU or different CUs based on the first offset value.

[0232] In some implementations, the sixth information implicitly indicates the first offset value. This can be understood as indicating a target network device belonging to the same CU as the source network device, and / or a target network device not belonging to the same CU as the source network device. Accordingly, upon receiving the sixth information, the terminal device can determine the first offset value associated with the first condition corresponding to the target cell based on predefined information.

[0233] In some implementations, the target network device belonging to the same CU as the source network device can be referred to as the "network device of the target cell within the CU (intra-CU)".

[0234] In some implementations, target network devices that do not belong to the same CU as the source network device can be referred to as "inter-CU target cell network devices".

[0235] In some implementations, if the sixth information indicates a target network device belonging to the same CU as the source network device, and a target network device not belonging to the same CU as the source network device, the terminal device receives the sixth information and determines the first offset value of the first condition association corresponding to the target network device based on whether the network device of the target cell belongs to "target network devices belonging to the same CU as the source network device" or "target network devices not belonging to the same CU as the source network device," and predefined information. For example, the target cells of the terminal device include cell A and cell B. The sixth information sent by the source network device to the terminal device indicates that the network device of cell A belongs to the same CU as the network device of the source cell, and the network device of cell B belongs to a different CU than the network device of the source cell. That is, cell A is an intra-CU cell, and cell B is an inter-CU cell. The predefined information indicates that the first offset value of the first condition association corresponding to the intra-CU cell is offset_A, and the first offset value of the first condition association corresponding to the inter-CU cell is offset_B. Upon receiving the sixth information, the terminal device can determine that cell A is an intra-CU cell and cell B is an inter-CU cell. Based on predefined information, it then determines that the first offset value for the first condition corresponding to cell A is offset_A, and the first offset value for the first condition corresponding to cell B is offset_B. The condition switching threshold is the absolute threshold A. Therefore, the first condition for cell A can be "measuring channel quality satisfies the absolute threshold A + offset_A". If the first condition is met, the terminal device sends the first information to the source network device to request the TA of cell A. Similarly, the first condition for cell B can be "measuring channel quality satisfies the absolute threshold A + offset_B". Therefore, if the first condition is met, the terminal device sends the first information to the source network device to request the TA of cell B.

[0236] As mentioned above, before the conditional handover, the terminal device can obtain the first TA corresponding to the target cell, but there may be a situation where the first TA is invalid and the terminal device has not yet completed the conditional handover.

[0237] To address this issue, this application also provides a wireless communication method in which a terminal device, after receiving a first TA corresponding to a network device in a target cell, starts one or more second timers. The second timers are used to record the validity period of the first TA, which helps to increase the probability that the terminal device completes conditional handover within the validity period of the first TA.

[0238] The following example, Example 3, describes a scheme for starting a second timer on a terminal device.

[0239] Example 3: The terminal device starts the second timer.

[0240] In some implementations, in response to receiving a first TA corresponding to one or more target network devices, the terminal device starts one or more second timers. The second timers are used to record the validity period of the first TA. Alternatively, in response to receiving third information, the terminal device starts one or more second timers.

[0241] In some implementations, the second timer is the timer T1 mentioned above.

[0242] In some implementations, the third information is also used to indicate the index of the target cell. For example, the third information received by the terminal device indicates the first TA corresponding to the network devices of cell A and cell B. In order to distinguish the first TA corresponding to different cells, the third information can also indicate the index of cell A and cell B, so that the cells correspond one-to-one with the first TA.

[0243] In some implementations, the index of the target cell can be carried by the sixth information mentioned above. For example, the sixth information is carried in an RRC reconfiguration message, which also carries a list of target cells for the terminal device, and the indexes in this list correspond to the indexes of the target cells indicated by the third information.

[0244] In this embodiment of the application, the number of second timers started by the terminal device is not limited.

[0245] In some implementations, the terminal device can start a second timer for all target cells associated with the third information; this second timer can be called a common second timer. For example, if the third information is used to indicate the first TA corresponding to the network devices in cell A and cell B, the terminal device can start a second timer to indicate the valid time corresponding to the network devices in cell A and cell B.

[0246] In some implementations, the terminal device can start a second timer for each target cell associated with the third information. That is, the second timer corresponds one-to-one with the target cell associated with the third information. For example, if the third information is used to indicate the first TA corresponding to the network devices of cell A and cell B, the terminal device can start two second timers. The two second timers are used to indicate the validity period of the first TA corresponding to the network device of cell A and the validity period of the first TA corresponding to the network device of cell B, respectively.

[0247] In some implementations, the target cells associated with the third information can be grouped, and a second timer can be started for each group. For example, the third information is used to indicate the first TA corresponding to the network devices of cells A, B, C, and D. Cells A and B constitute the first group, and cells C and D constitute the second group. The terminal device starts two second timers for the first group and the second group respectively. The two second timers are used to indicate the validity period of the first TA corresponding to the network devices of cells A and B, and the validity period of the first TA corresponding to the network devices of cells C and D, respectively.

[0248] In some implementations, target cells associated with the third information can be grouped based on the frequency band to which they belong. For example, target cells associated with the third information of FR1 constitute the first group, and target cells associated with the third information of FR2 constitute the second group.

[0249] In some implementations, the target cell can be grouped based on the CU to which it belongs, associated with the third information. For example, the third information is used to indicate the first TA corresponding to the network devices of cells A, B, C, and D. Cells A and B belong to the first CU, cell C belongs to the second CU, and cell D belongs to the third CU. The terminal device starts three second timers for the first CU, the second CU, and the third CU, respectively. The three second timers indicate the validity period of the first TA corresponding to the network devices of cells A and B, the first TA corresponding to the network devices of cell C, and the first TA corresponding to the network devices of cell D.

[0250] In some implementations, the duration of the second timer is predefined or configured by the source network device. For example, the protocol specifies the duration of the second timer. Alternatively, the source network device configures the duration of the second timer.

[0251] In some implementations, the duration of the second timer is carried in the conditional handover configuration sent by the source network device to the terminal device. For example, referring to Figure 5, in step S510, the source cell sends a conditional handover configuration to the terminal device. The conditional handover configuration may carry the duration of the second timer corresponding to multiple target cells, or the duration of the common second timer corresponding to multiple target cells.

[0252] In some implementations, the duration of the different second timers varies. For example, the third information is used to indicate the first TA corresponding to the network devices in cells A, B, and C. The terminal device starts a second timer for each target cell, that is, a total of 3 second timers are started, and the duration of the 3 second timers is different.

[0253] In some implementations, the durations of different second timers can be the same. For example, the third information is used to indicate the first TA corresponding to the network devices in cells A, B, and C. The terminal device starts a second timer for each target cell, that is, a total of 3 second timers are started, and the durations of the 3 second timers are all the same.

[0254] In some implementations, among the target cells associated with the third information, the duration of the second timer corresponding to target cells belonging to the same frequency band is the same, while the duration of the second timer corresponding to target cells belonging to different frequency bands is different. For example, among the target cells associated with the third information, the duration of the second timer corresponding to the target cell belonging to FR1 is the first value, and the duration of the second timer corresponding to the target cell belonging to FR2 is the second value; the first value and the second value are different. As another example, the third information is used to indicate the first TA corresponding to the network devices of cells A, B, and C. Cells A and B belong to FR1, and cell C belongs to FR2. The terminal device starts one second timer for each target cell, that is, a total of three second timers are started. The duration of the two second timers corresponding to cells A and B is the first value, and the duration of the second timer corresponding to cell C is the second value; the first value and the second value are different.

[0255] In some implementations, if the terminal device receives a fifth message from the source network device during the operation of the second timer, the terminal device restarts the second timer. The fifth message is used to indicate the second TA corresponding to the target network device associated with the second timer. The newly started second timer is used to record the validity period of the second TA. That is to say, if the source network device updates the TA corresponding to the target network device associated with the second timer during the operation of the second timer, the terminal device restarts the second timer. The restarted second timer is used to record the validity period of the updated TA.

[0256] In some implementations, restarting the second timer can be understood as stopping the already started second timer and starting a new second timer for the target cell corresponding to the old second timer.

[0257] In some implementations, if the second timer corresponds to a target cell, and the fifth information received by the terminal device indicates the second TA of the network device in that target cell, then the terminal device restarts the second timer. The second timer is used to record the validity period of the second TA. For example, if the second timer is started by the terminal device for cell A associated with the third information, then during the operation of the second timer, if the fifth information received by the terminal device indicates the second TA corresponding to the network device of cell A, and the second TA is different from the first TA, then the terminal device stops the already started second timer corresponding to cell A and starts a new second timer for cell A.

[0258] In some implementations, if the second timer corresponds to multiple target cells or a group of target cells, and the fifth information received by the terminal device indicates the second TA corresponding to the network device of some of the multiple target cells or the group of target cells, then the terminal device restarts the second timer. The second timer is used to record the validity period of the second TA corresponding to the network device of some of the multiple target cells or the group of target cells. For example, if the second timer is started by the terminal device for cells A and B associated with the third information, then during the operation of the second timer, if the fifth information received by the terminal device indicates the second TA corresponding to the network device of cell A, then the terminal device stops the already started second timer for cells A and B, and starts a new second timer for cells A and B. The new second timer is used to record the validity period of the second TA corresponding to cell A.

[0259] In some implementations, if the second timer corresponds to multiple target cells or a group of target cells, the fifth information received by the terminal device indicates the second TA corresponding to the network devices of all target cells in the multiple target cells or group of target cells corresponding to the second timer. The terminal device then restarts the second timer, which is used to record the validity period of the second TA corresponding to the multiple target cells or group of target cells. For example, if the second timer is started by the terminal device for cells A and B associated with the third information, then during the operation of the second timer, if the fifth information received by the terminal device indicates the second TA corresponding to the network devices of cells A and B, the terminal device stops the already started second timer for cells A and B and starts a new second timer for cells A and B. The new second timer is used to record the validity period of the second TA corresponding to cells A and B.

[0260] In some implementations, during the operation of the second timer, the terminal device selects a first target network device from one or more target network devices associated with the second timer for switching based on the first rule and condition switching configuration.

[0261] In some implementations, during the second timer's operation, the terminal device selects a first target network device for handover from one or more target network devices associated with the second timer, based on the first rule and conditional handover configuration. This can be understood as follows: during the second timer's operation, the terminal device performs measurements; among the one or more target network devices associated with the second timer, it determines target cells whose measurement results meet the conditions for conditional handover based on the conditional handover configuration; and from the network devices of target cells meeting the conditional handover conditions, it selects the first target network device for handover based on the first rule. For example, if the second timer is started by the terminal device for cells A, B, and C, and the terminal device determines that the measurement results of cells A and C meet the conditions for conditional handover based on the conditional handover configuration, then the terminal device selects the network device of the cell to be handed over from the network devices of cells A and C based on the first rule.

[0262] In some implementations, the first rule is used to instruct the terminal device on the priority of selecting the target network device.

[0263] In some implementations, the first rule includes one or more of the following: prioritizing target network devices belonging to the same CU as the source network device; prioritizing target network devices with valid TA.

[0264] In some implementations, the first rule is used to instruct the terminal device to select the priority of the target network device for conditional handover from multiple target network devices that meet the conditions for conditional handover.

[0265] In some implementations, the first rule is used to instruct the terminal device on the priority of selecting a target network device for conditional handover from multiple target network devices that meet the handover conditions. The first rule includes prioritizing target network devices belonging to the same CU as the source network device. This can be understood as follows: if network devices in both intra-CU and inter-CU target cells simultaneously meet the handover conditions, the first rule instructs that the network device in the intra-CU target cell be prioritized for handover. For example, if the target network devices meeting the handover conditions include network devices in cell A and cell B, where cell A is an intra-CU cell and cell B is an inter-CU cell, then based on the first rule, the terminal device can select the network device in cell A as the first target network device for handover.

[0266] In some implementations, if multiple intra-CU target cell network devices meet the conditions for conditional handover, the terminal device will automatically select one network device as the target network device and perform the handover.

[0267] In some implementations, the first rule is used to instruct the terminal device on the priority of selecting a target network device for conditional handover from multiple target network devices that meet the handover conditions. The first rule includes prioritizing target network devices with valid TAs. This can be understood as follows: if network devices in a target cell with both valid and invalid TAs simultaneously meet the handover conditions, the first rule instructs that the network device in the target cell with valid TAs be prioritized for handover. For example, if the target network devices meeting the handover conditions include network devices in cell A and cell B, where cell A has a valid TA and cell B has an invalid TA, then based on the first rule, the terminal device can select the network device in cell A as the first target network device for handover.

[0268] In some implementations, the first rule is used to instruct the terminal device to select a target network device for conditional handover from multiple target network devices that meet the handover conditions. The first rule includes prioritizing target network devices belonging to the same CU as the source network device and prioritizing target network devices with valid TAs. This can be understood as follows: if network devices in cells with valid intra-CUs, valid inter-CUs, invalid intra-CUs, and invalid inter-CUs simultaneously meet the handover conditions, the first rule indicates the priority for selecting the first target network device from these four types of target network devices. For example, referring to Table 1, the first rule indicates that network devices in cells with valid intra-CUs have the highest priority, network devices in cells with valid inter-CUs have the second highest priority, network devices in cells with invalid intra-CUs have the lowest priority, and network devices in cells with invalid inter-CUs have the lowest priority.

[0269] Table 1

[0270] In some implementations, if the two target network devices indicated by the first rule have the same priority, a target network device with a higher priority can be predefined or configured by the source network device. For example, referring to Table 1, the first rule indicates that the network device in a cell with a valid intra-CU has the highest priority, the network device in a cell with a valid inter-CU has the second highest priority, the network device in a cell with an invalid intra-CU has the lowest priority, and the network device in a cell with an invalid inter-CU has the lowest priority. For the two target network devices with the second priority, the protocol can specify which target network device has a higher priority, or the source network device can configure which target network device has a higher priority.

[0271] In some implementations, if the second timer times out and the terminal device fails to select the first target network device from one or more target network devices associated with the second timer, the terminal device sends the first information to the source network device if the first condition is met. That is, if the TA of the target network device associated with the second timer fails, if the terminal device has not yet performed condition switching, and the current measurement result of the terminal device meets the first condition, the terminal device sends the first information to the source network device to request the TA of the target network device again.

[0272] The preceding sections, through Examples 1, 2, and 3, respectively introduced the relevant schemes for a terminal device to start one or more first timers, configure the switching of first condition association conditions, and start a second timer. In some scenarios, the three schemes can be used independently. In other scenarios, the three schemes can be used in combination.

[0273] The method embodiments of this application have been described in detail above with reference to Figures 1 to 6. The apparatus embodiments of this application will be described in detail below with reference to Figures 7 to 10. It should be understood that the descriptions of the method embodiments correspond to the descriptions of the apparatus embodiments; therefore, any parts not described in detail can be referred to the preceding method embodiments.

[0274] Figure 7 is a schematic diagram of a terminal device according to an embodiment of this application. The terminal device 700 shown in Figure 7 includes: a startup unit 710.

[0275] The startup unit 710 is configured to start one or more first timers, the first timers being configured to indicate one or more of the following: the duration for which the terminal device waits to receive a first timing advance (TA) corresponding to one or more target network devices, the first TA being used by the terminal device to perform condition switching; the duration for which the terminal device waits to receive response information sent by the source network device, the response information being used by the source network device to respond to a measurement report sent by the terminal device.

[0276] In some implementations, before the terminal device starts the first timer, the terminal device further includes: a sending unit, configured to send first information to the source network device, the first information being used to indicate a measurement report; or configured to send second information to the target network device, the second information being used to indicate a preamble.

[0277] In some implementations, the terminal device further includes a stop unit, which stops the first timer if the terminal device receives third information sent by the source network device during the operation of the first timer; wherein the third information is used to indicate a first TA corresponding to one or more of the target network devices.

[0278] In some implementations, the terminal device further includes a stop unit, which stops the first timer if the terminal device receives fourth information sent by the source network device during the operation of the first timer; wherein the fourth information is used to instruct the terminal device to send a preamble to one or more of the target network devices.

[0279] In some implementations, if the first timer times out, the terminal device further includes: a sending unit, configured to send first information to the source network device; or if a first condition is met, configured to send first information to the source network device.

[0280] In some implementations, the terminal device further includes: in response to receiving a first TA corresponding to one or more of the target network devices, the startup unit 710 is further configured to start one or more second timers, the second timers being configured to record the validity period of the first TA.

[0281] In some implementations, the terminal device further includes: during the operation of the second timer, if the terminal device receives fifth information sent by the source network device, the startup unit 710 is further used to restart the second timer; wherein the fifth information is used to indicate the second TA corresponding to the target network device associated with the second timer, and the newly started second timer is used to record the validity period of the second TA.

[0282] In some implementations, the terminal device further includes a selection unit, which, during the operation of the second timer, is configured to select a first target network device for switching from one or more target network devices associated with the second timer based on a first rule and / or conditional switching configuration; wherein the first rule is used to indicate the priority of the terminal device in selecting the target network device.

[0283] In some implementations, the first rule includes one or more of the following: preferentially selecting target network devices that belong to the same central unit (CU) as the source network device; preferentially selecting target network devices with valid TAs.

[0284] In some implementations, if the second timer times out and the terminal device fails to select a first target network device from one or more target network devices associated with the second timer, the terminal device further includes a sending unit, which, if a first condition is met, is used to send first information to the source network device.

[0285] In some implementations, the transmission of the first information is triggered based on a first condition, which is associated with one or more of the following: the condition switching configuration of the terminal device; and a first offset value, which indicates the offset between the trigger threshold of the measurement report and the condition switching threshold indicated by the condition switching configuration.

[0286] In some implementations, the first offset value is determined based on one or more of the following: the CU to which the target network device belongs; whether the CU to which the source network device belongs is the same as the CU to which the target network device belongs; and the frequency band corresponding to the target network device.

[0287] In some implementations, before the terminal device sends the first information, the terminal device further includes: a receiving unit, configured to receive sixth information sent by the source network device, the sixth information indicating one or more of the following: the conditional switching configuration of the terminal device; a first offset value, the first offset value indicating the offset value between the trigger threshold of the measurement report and the conditional switching threshold indicated by the conditional switching configuration; a target network device belonging to the same CU as the source network device; and a target network device not belonging to the same CU as the source network device.

[0288] In some implementations, the duration of the first timer and / or the second timer is predefined or configured by the source network device.

[0289] In some implementations, the durations of the first timer and / or the second timer are different; or the durations of the first timer and / or the second timer are the same.

[0290] In some implementations, the first information is carried in one or more of the following: Physical Uplink Control Channel (PUCCH); Media Access Control Element (MAC CE); Radio Resource Control (RRC) message.

[0291] In some implementations, if the first information is carried in a MAC CE, the first information is also used to indicate the cell information to which one or more of the target network devices belong.

[0292] Figure 8 is a schematic diagram of a network device according to an embodiment of this application. The network device 800 shown in Figure 8 can be a source network device. The network device 800 includes a receiving unit 810.

[0293] The receiving unit 810 is configured to receive first information sent by the terminal device, wherein the first information is used to indicate a measurement report; wherein, sending the first information is used to trigger the terminal device to start one or more first timers, the first timers being used to indicate one or more of the following: the duration for which the terminal device waits to receive a first timing advance (TA) corresponding to one or more target network devices, the first TA being used by the terminal device to perform condition switching; the duration for which the terminal device waits to receive response information sent by the source network device, the response information being used by the source network device to respond to the measurement report sent by the terminal device.

[0294] In some implementations, the network device further includes: a sending unit, configured to send third information to the terminal device; wherein the third information is used to indicate a first TA corresponding to one or more of the target network devices.

[0295] In some implementations, before the source network device sends the three pieces of information, the network device further includes: the sending unit is also configured to send a fourth piece of information to the terminal device; wherein the fourth piece of information is used to instruct the terminal device to send a preamble to one or more of the target network devices.

[0296] In some implementations, the third and / or fourth information is used to trigger the terminal device to stop the first timer.

[0297] In some implementations, the network device further includes: the receiving unit 810 is also configured to receive first information sent by the terminal device, the first information being sent after the first timer expires.

[0298] In some implementations, the third information is used to trigger the terminal device to start one or more second timers, which are used to record the validity period of the first TA.

[0299] In some implementations, the network device further includes: the sending unit is further configured to send fifth information to the terminal device, the fifth information being used to trigger the terminal device to restart the second timer; wherein, the fifth information is used to indicate the second TA corresponding to the target network device associated with the second timer, and the newly started second timer is used to record the validity period of the second TA.

[0300] In some implementations, the network device further includes: the receiving unit 810 is also configured to receive first information sent by the terminal device, wherein the first information is sent based on a first condition when the second timer expires and the terminal device does not perform a condition switch.

[0301] In some implementations, the transmission of the first information is triggered based on a first condition, which is associated with one or more of the following: the condition switching configuration of the terminal device; and a first offset value, which indicates the offset between the trigger threshold of the measurement report and the condition switching threshold indicated by the condition switching configuration.

[0302] In some implementations, the first offset value is determined based on one or more of the following: the CU to which the target network device belongs; whether the CU to which the source network device belongs is the same as the CU to which the target network device belongs; and the frequency band corresponding to the target network device.

[0303] In some implementations, before the terminal device sends the first information, the network device further includes: a sending unit, configured to send sixth information to the terminal device, the sixth information indicating one or more of the following: the conditional switching configuration of the terminal device; a first offset value, the first offset value indicating the offset value between the trigger threshold of the measurement report and the conditional switching threshold indicated by the conditional switching configuration; a target network device belonging to the same CU as the source network device; and a target network device not belonging to the same CU as the source network device.

[0304] In some implementations, the duration of the first timer and / or the second timer is predefined or configured by the source network device.

[0305] In some implementations, the durations of the first timer and / or the second timer are different; or the durations of the first timer and / or the second timer are the same.

[0306] In some implementations, the first information is carried in one or more of the following: Physical Uplink Control Channel (PUCCH); Media Access Control Element (MAC CE); Radio Resource Control (RRC) message.

[0307] In some implementations, if the first information is carried in a MAC CE, the first information is also used to indicate the cell information to which one or more of the target network devices belong.

[0308] Figure 9 is a schematic diagram of a network device according to an embodiment of this application. The network device 900 shown in Figure 9 can be a target network device. The network device 900 includes: a receiving unit 910.

[0309] The receiving unit 910 is used to receive second information sent by the terminal device, the second information being used to indicate a preamble; wherein, the sending of the second information is used to trigger the terminal device to start one or more first timers, the first timers being used to indicate the duration for which the terminal device waits to receive a first timing advance TA corresponding to one or more of the target network devices, the first TA being used by the terminal device to perform condition switching.

[0310] In some implementations, the network device further includes a sending unit for sending a first TA corresponding to the target network device to the source network device.

[0311] In some implementations, the network device further includes: the sending unit is also configured to send a second TA corresponding to the target network device to the source network device.

[0312] In an optional embodiment, the startup unit 710 may be a processor 1010. The terminal device 700 may also include a transceiver 1030 and a memory 1020, as shown in FIG10.

[0313] In an optional embodiment, the receiving unit 810 may be a transceiver 1030. The network device 800 may also include a processor 1010 and a memory 1020, as shown in FIG10.

[0314] In an optional embodiment, the receiving unit 910 may be a transceiver 1030, and the network device 900 may also include a processor 1010 and a memory 1020, as shown in FIG10.

[0315] Figure 10 is a schematic structural diagram of a communication device according to an embodiment of this application. The dashed lines in Figure 10 indicate that the unit or module is optional. This device 1000 can be used to implement the methods described in the above method embodiments. The device 1000 can be a chip, a terminal device, or a network device.

[0316] Apparatus 1000 may include one or more processors 1010. The processor 1010 may support apparatus 1000 in implementing the methods described in the preceding method embodiments. The processor 1010 may be a general-purpose processor or a special-purpose processor. For example, the processor may be a central processing unit (CPU). Alternatively, the processor may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0317] The apparatus 1000 may further include one or more memories 1020. The memories 1020 store a program that can be executed by the processor 1010, causing the processor 1010 to perform the methods described in the preceding method embodiments. The memories 1020 may be independent of the processor 1010 or integrated within the processor 1010.

[0318] The device 1000 may also include a transceiver 1030. The processor 1010 can communicate with other devices or chips via the transceiver 1030. For example, the processor 1010 can send and receive data with other devices or chips via the transceiver 1030.

[0319] This application also provides a computer-readable storage medium for storing a program. This computer-readable storage medium can be applied to a terminal or network device provided in this application, and the program causes a computer to execute the methods performed by the terminal or network device in various embodiments of this application.

[0320] This application also provides a computer program product. The computer program product includes a program. The computer program product can be applied to a terminal or network device provided in this application embodiment, and the program causes a computer to execute the methods performed by the terminal or network device in various embodiments of this application.

[0321] This application also provides a computer program. This computer program can be applied to the terminal or network device provided in this application, and the computer program causes the computer to execute the methods performed by the terminal or network device in various embodiments of this application.

[0322] It should be understood that the terms "system" and "network" in this application can be used interchangeably. Furthermore, the terminology used in this application is only for explaining specific embodiments of the application and is not intended to limit the application. The terms "first," "second," "third," and "fourth," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. In addition, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0323] In the embodiments of this application, the term "instruction" can be a direct instruction, an indirect instruction, or an indication of a relationship. For example, A instructing B can mean that A directly instructs B, such as B being able to obtain information through A; it can also mean that A indirectly instructs B, such as A instructing C, so B can obtain information through C; or it can mean that there is a relationship between A and B.

[0324] In the embodiments of this application, the term "correspondence" can indicate a direct or indirect correspondence between two things, or an association between two things, or a relationship such as instruction and being instructed, configuration and being configured.

[0325] In this application embodiment, "predefined" or "preconfigured" can be implemented by pre-storing corresponding codes, tables, or other means that can be used to indicate relevant information in the device (e.g., including terminal devices and network devices). This application does not limit the specific implementation method. For example, predefined can refer to what is defined in the protocol.

[0326] In this application embodiment, the "protocol" may refer to a standard protocol in the field of communication, such as the LTE protocol, the NR protocol, and related protocols applied to future communication systems. This application does not limit this.

[0327] In the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0328] In the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0329] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, 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 coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0330] 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.

[0331] 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.

[0332] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions 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, fiber optic, 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 read 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 disks, SSDs), etc.

[0333] 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 method for wireless communication, characterized in that, include: The terminal device starts one or more first timers, the first timers being used to indicate one or more of the following: The duration for which the terminal device waits to receive a first timing advance (TA) corresponding to one or more target network devices, the first TA being used by the terminal device to perform condition switching; The duration for which the terminal device waits to receive response information sent by the source network device, wherein the response information is used by the source network device to respond to the measurement report sent by the terminal device.

2. The method as described in claim 1, characterized in that, Before the terminal device starts the first timer, the method further includes: The terminal device sends first information to the source network device, the first information being used to indicate a measurement report; or The terminal device sends a second message to the target network device, the second message being used to indicate a preamble.

3. The method as described in claim 1 or 2, characterized in that, The method further includes: If the terminal device receives third information sent by the source network device during the operation of the first timer, the terminal device stops the first timer. The third information is used to indicate the first TA corresponding to one or more of the target network devices.

4. The method as described in claim 1 or 2, characterized in that, The method further includes: If the terminal device receives the fourth information sent by the source network device during the operation of the first timer, the terminal device stops the first timer. The fourth piece of information is used to instruct the terminal device to send a preamble to one or more of the target network devices.

5. The method as described in claim 3, characterized in that, If the first timer times out, the method further includes: The terminal device sends first information to the source network device; or If the first condition is met, the terminal device sends the first information to the source network device.

6. The method according to any one of claims 3-5, characterized in that, The method further includes: In response to receiving a first TA corresponding to one or more of the target network devices, the terminal device starts one or more second timers, which are used to record the validity period of the first TA.

7. The method as described in claim 6, characterized in that, The method further includes: If the terminal device receives the fifth information sent by the source network device during the operation of the second timer, the terminal device restarts the second timer. The fifth piece of information is used to indicate the second TA corresponding to the target network device associated with the second timer, and the newly started second timer is used to record the validity period of the second TA.

8. The method as described in claim 6 or 7, characterized in that, The method further includes: During the operation of the second timer, the terminal device selects a first target network device from one or more target network devices associated with the second timer for switching based on the first rule and / or condition switching configuration; The first rule is used to instruct the terminal device to select the priority of the target network device.

9. The method as described in claim 8, characterized in that, The first rule includes one or more of the following: Prioritize selecting target network devices that belong to the same central unit (CU) as the source network device; Prioritize selecting target network devices that are valid for TA.

10. The method according to any one of claims 7-9, characterized in that, If the second timer times out and the terminal device fails to select the first target network device from one or more target network devices associated with the second timer, the method further includes: If the first condition is met, the terminal device sends the first information to the source network device.

11. The method as described in claim 2, characterized in that, The sending of the first information is triggered based on a first condition, which is associated with one or more of the following: The conditional switching configuration of the terminal device; A first offset value is used to indicate the offset between the trigger threshold of the measurement report and the condition switching threshold indicated by the condition switching configuration.

12. The method as described in claim 11, characterized in that, The first offset value is determined based on one or more of the following: The target network device belongs to the CU; Whether the CU to which the source network device belongs is the same as the CU to which the target network device belongs; The frequency band corresponding to the target network device.

13. The method as described in claim 2, characterized in that, Before the terminal device sends the first information, the method further includes: The terminal device receives a sixth message sent by the source network device, the sixth message indicating one or more of the following: The conditional switching configuration of the terminal device; A first offset value, which indicates the offset between the trigger threshold of the measurement report and the condition switching threshold indicated by the condition switching configuration; The target network device belongs to the same CU as the source network device; The target network device is not part of the same CU as the source network device.

14. The method according to any one of claims 6-13, characterized in that, The duration of the first timer and / or the second timer is predefined or configured by the source network device.

15. The method according to any one of claims 6-14, characterized in that, The durations of the first timer and / or the second timer are different; or The durations of the first timer and / or the second timer are the same.

16. The method as described in claim 2, characterized in that, The first information is carried in one or more of the following: Physical Uplink Control Channel (PUCCH); Media Access Control (MAC) CE; Radio Resource Control (RRC) message.

17. The method as described in claim 16, characterized in that, If the first information is carried in a MAC CE, the first information is also used to indicate the cell information to which one or more of the target network devices belong.

18. A method for wireless communication, characterized in that, include: The source network device receives first information sent by the terminal device, the first information being used to indicate a measurement report; The sending of the first information is used to trigger the terminal device to start one or more first timers, wherein the first timers are used to indicate one or more of the following: The duration for which the terminal device waits to receive a first timing advance (TA) corresponding to one or more target network devices, the first TA being used by the terminal device to perform condition switching; The duration for which the terminal device waits to receive response information sent by the source network device, wherein the response information is used by the source network device to respond to the measurement report sent by the terminal device.

19. The method as described in claim 18, characterized in that, The method further includes: The source network device sends third information to the terminal device; The third information is used to indicate the first TA corresponding to one or more of the target network devices.

20. The method as described in claim 19, characterized in that, Before the source network device sends the three pieces of information, the method further includes: The source network device sends fourth information to the terminal device; The fourth piece of information is used to instruct the terminal device to send a preamble to one or more of the target network devices.

21. The method as described in claim 20, characterized in that, The third and / or fourth information is used to trigger the terminal device to stop the first timer.

22. The method according to any one of claims 18-21, characterized in that, The method further includes: The source network device receives first information sent by the terminal device, which is sent after the first timer expires.

23. The method according to any one of claims 20-22, characterized in that, The third information is used to trigger the terminal device to start one or more second timers, the second timers being used to record the effective time of the first TA.

24. The method as described in claim 23, characterized in that, The method further includes: The source network device sends a fifth message to the terminal device, the fifth message being used to trigger the terminal device to restart the second timer; The fifth piece of information is used to indicate the second TA corresponding to the target network device associated with the second timer, and the newly started second timer is used to record the validity period of the second TA.

25. The method as described in claim 23 or 24, characterized in that, The method further includes: The source network device receives first information sent by the terminal device. The first information is sent based on a first condition when the second timer expires and the terminal device does not perform a condition switch.

26. The method as described in claim 18, characterized in that, The sending of the first information is triggered based on a first condition, which is associated with one or more of the following: The conditional switching configuration of the terminal device; A first offset value is used to indicate the offset between the trigger threshold of the measurement report and the condition switching threshold indicated by the condition switching configuration.

27. The method as described in claim 26, characterized in that, The first offset value is determined based on one or more of the following: The target network device belongs to the central unit (CU); Whether the CU to which the source network device belongs is the same as the CU to which the target network device belongs; The frequency band corresponding to the target network device.

28. The method as described in claim 18, characterized in that, Before the terminal device sends the first information, the method further includes: The source network device sends a sixth message to the terminal device, the sixth message indicating one or more of the following: The conditional switching configuration of the terminal device; A first offset value, which indicates the offset between the trigger threshold of the measurement report and the condition switching threshold indicated by the condition switching configuration; The target network device belongs to the same CU as the source network device; The target network device is not part of the same CU as the source network device.

29. The method according to any one of claims 23-28, characterized in that, The duration of the first timer and / or the second timer is predefined or configured by the source network device.

30. The method according to any one of claims 23-29, characterized in that, The durations of the first timer and / or the second timer are different; or The durations of the first timer and / or the second timer are the same.

31. The method according to any one of claims 18-30, characterized in that, The first information is carried in one or more of the following: Physical Uplink Control Channel (PUCCH); Media Access Control (MAC) CE; Radio Resource Control (RRC) message.

32. The method as described in claim 31, characterized in that, If the first information is carried in a MAC CE, the first information is also used to indicate the cell information to which one or more of the target network devices belong.

33. A method for wireless communication, characterized in that, include: The target network device receives second information sent by the terminal device, the second information being used to indicate a preamble; The sending of the second information is used to trigger the terminal device to start one or more first timers. The first timers are used to indicate the duration for which the terminal device waits to receive the first timing advance (TA) corresponding to one or more target network devices. The first TA is used by the terminal device to perform condition switching.

34. The method as described in claim 33, characterized in that, The method further includes: The target network device sends the first TA corresponding to the target network device to the source network device.

35. The method as described in claim 34, characterized in that, The method further includes: The target network device sends the second TA corresponding to the target network device to the source network device.

36. A terminal device, characterized in that, The terminal device includes: A startup unit is configured to start one or more first timers, the first timers being configured to indicate one or more of the following: The terminal device waits for the duration of the first advance timing (TA) corresponding to one or more target network devices, and the first TA is used by the terminal device to perform condition switching. The duration for which the terminal device waits to receive response information sent by the source network device, wherein the response information is used by the source network device to respond to the measurement report sent by the terminal device.

37. The terminal device as described in claim 36, characterized in that, Before the terminal device starts the first timer, the terminal device further includes: A sending unit is configured to send first information to the source network device, the first information being used to indicate a measurement report; or Used to send a second message to the target network device, the second message being used to indicate a preamble.

38. The terminal device as described in claim 36 or 37, characterized in that, The terminal device also includes: The stop unit is used to stop the first timer if the terminal device receives third information sent by the source network device during the operation of the first timer. The third information is used to indicate the first TA corresponding to one or more of the target network devices.

39. The terminal device as described in claim 36 or 37, characterized in that, The terminal device also includes: The stop unit is used to stop the first timer if the terminal device receives the fourth information sent by the source network device during the operation of the first timer. The fourth piece of information is used to instruct the terminal device to send a preamble to one or more of the target network devices.

40. The terminal device as described in claim 38, characterized in that, If the first timer times out, the terminal device further includes: The sending unit is configured to send first information to the source network device; or If the first condition is met, the first information is sent to the source network device.

41. The terminal device as described in any one of claims 38-40, characterized in that, The terminal device also includes: In response to receiving a first TA corresponding to one or more of the target network devices, the startup unit is further configured to start one or more second timers, the second timers being used to record the validity period of the first TA.

42. The terminal device as described in claim 41, characterized in that, The terminal device also includes: During the operation of the second timer, if the terminal device receives the fifth information sent by the source network device, the startup unit is also used to restart the second timer; The fifth piece of information is used to indicate the second TA corresponding to the target network device associated with the second timer, and the newly started second timer is used to record the validity period of the second TA.

43. The terminal device as described in claim 41 or 42, characterized in that, The terminal device also includes: During the operation of the second timer, the selection unit is used to select a first target network device for switching from one or more target network devices associated with the second timer based on a first rule and / or conditional switching configuration; The first rule is used to instruct the terminal device to select the priority of the target network device.

44. The terminal device as described in claim 43, characterized in that, The first rule includes one or more of the following: Prioritize selecting target network devices that belong to the same central unit (CU) as the source network device; Prioritize selecting target network devices that are valid for TA.

45. The terminal device as described in any one of claims 42-44, characterized in that, If the second timer times out, and the terminal device fails to select a first target network device from one or more target network devices associated with the second timer, the terminal device further includes: If the first condition is met, the sending unit is used to send first information to the source network device.

46. ​​The terminal device as described in claim 37, characterized in that, The sending of the first information is triggered based on a first condition, which is associated with one or more of the following: The conditional switching configuration of the terminal device; A first offset value is used to indicate the offset between the trigger threshold of the measurement report and the condition switching threshold indicated by the condition switching configuration.

47. The terminal device as described in claim 46, characterized in that, The first offset value is determined based on one or more of the following: The target network device belongs to the CU; Whether the CU to which the source network device belongs is the same as the CU to which the target network device belongs; The frequency band corresponding to the target network device.

48. The terminal device as described in claim 37, characterized in that, Before the terminal device sends the first information, the terminal device further includes: A receiving unit is configured to receive sixth information sent by the source network device, the sixth information indicating one or more of the following: The conditional switching configuration of the terminal device; A first offset value, which indicates the offset between the trigger threshold of the measurement report and the condition switching threshold indicated by the condition switching configuration; The target network device belongs to the same CU as the source network device; The target network device is not part of the same CU as the source network device.

49. The terminal device as described in any one of claims 42-48, characterized in that, The duration of the first timer and / or the second timer is predefined or configured by the source network device.

50. The terminal device as described in any one of claims 42-49, characterized in that, The durations of the first timer and / or the second timer are different; or The durations of the first timer and / or the second timer are the same.

51. The terminal device as described in claim 37, characterized in that, The first information is carried in one or more of the following: Physical Uplink Control Channel (PUCCH); Media Access Control (MAC) CE; Radio Resource Control (RRC) message.

52. The terminal device as described in claim 51, characterized in that, If the first information is carried in a MAC CE, the first information is also used to indicate the cell information to which one or more of the target network devices belong.

53. A network device, characterized in that, The network device is a source network device, and the network device includes: A receiving unit is configured to receive first information sent by a terminal device, wherein the first information is used to indicate a measurement report. The sending of the first information is used to trigger the terminal device to start one or more first timers, wherein the first timers are used to indicate one or more of the following: The duration for which the terminal device waits to receive a first timing advance (TA) corresponding to one or more target network devices, the first TA being used by the terminal device to perform condition switching; The duration for which the terminal device waits to receive response information sent by the source network device, wherein the response information is used by the source network device to respond to the measurement report sent by the terminal device.

54. The network device as described in claim 53, characterized in that, The network device also includes: A sending unit is used to send third information to the terminal device; The third information is used to indicate the first TA corresponding to one or more of the target network devices.

55. The network device as described in claim 54, characterized in that, Before the source network device sends the three pieces of information, the network device further includes: The sending unit is also used to send fourth information to the terminal device; The fourth piece of information is used to instruct the terminal device to send a preamble to one or more of the target network devices.

56. The network device as described in claim 55, characterized in that, The third and / or fourth information is used to trigger the terminal device to stop the first timer.

57. The network device as described in any one of claims 53-56, characterized in that, The network device also includes: The receiving unit is also used to receive first information sent by the terminal device, the first information being sent after the first timer expires.

58. The network device as described in any one of claims 55-57, characterized in that, The third information is used to trigger the terminal device to start one or more second timers, the second timers being used to record the effective time of the first TA.

59. The network device as described in claim 58, characterized in that, The network device also includes: The sending unit is further configured to send fifth information to the terminal device, the fifth information being used to trigger the terminal device to restart the second timer; The fifth piece of information is used to indicate the second TA corresponding to the target network device associated with the second timer, and the newly started second timer is used to record the validity period of the second TA.

60. The network device as described in claim 58 or 59, characterized in that, The network device also includes: The receiving unit is further configured to receive first information sent by the terminal device, wherein the first information is sent based on a first condition when the second timer expires and the terminal device does not perform a condition switch.

61. The network device as described in claim 53, characterized in that, The sending of the first information is triggered based on a first condition, which is associated with one or more of the following: The conditional switching configuration of the terminal device; A first offset value is used to indicate the offset between the trigger threshold of the measurement report and the condition switching threshold indicated by the condition switching configuration.

62. The network device as described in claim 61, characterized in that, The first offset value is determined based on one or more of the following: The target network device belongs to the central unit (CU); Whether the CU to which the source network device belongs is the same as the CU to which the target network device belongs; The frequency band corresponding to the target network device.

63. The network device as described in claim 53, characterized in that, Before the terminal device sends the first information, the network device further includes: The sending unit is configured to send sixth information to the terminal device, the sixth information indicating one or more of the following: The conditional switching configuration of the terminal device; A first offset value, which indicates the offset between the trigger threshold of the measurement report and the condition switching threshold indicated by the condition switching configuration; The target network device belongs to the same CU as the source network device; The target network device is not part of the same CU as the source network device.

64. The network device as described in any one of claims 58-63, characterized in that, The duration of the first timer and / or the second timer is predefined or configured by the source network device.

65. The network device as described in any one of claims 58-64, characterized in that, The durations of the first timer and / or the second timer are different; or The durations of the first timer and / or the second timer are the same.

66. The network device as described in any one of claims 53-65, characterized in that, The first information is carried in one or more of the following: Physical Uplink Control Channel (PUCCH); Media Access Control (MAC) CE; Radio Resource Control (RRC) message.

67. The network device as described in claim 66, characterized in that, If the first information is carried in a MAC CE, the first information is also used to indicate the cell information to which one or more of the target network devices belong.

68. A network device, characterized in that, The network device is the target network device, and the network device includes: A receiving unit is configured to receive second information sent by a terminal device, wherein the second information is used to indicate a preamble. The sending of the second information is used to trigger the terminal device to start one or more first timers. The first timers are used to indicate the duration for which the terminal device waits to receive the first timing advance (TA) corresponding to one or more target network devices. The first TA is used by the terminal device to perform condition switching.

69. The network device as described in claim 68, characterized in that, The network device also includes: The sending unit is used to send the first TA corresponding to the target network device to the source network device.

70. The network device as described in claim 69, characterized in that, The network device also includes: The sending unit is also used to send the second TA corresponding to the target network device to the source network device.

71. A terminal device, characterized in that, The device includes a transceiver, a memory, and a processor. The memory is used to store a program, and the processor is used to invoke the program in the memory and control the transceiver to receive or send signals so that the terminal performs the method as described in any one of claims 1-17.

72. A network device, characterized in that, The device includes a transceiver, a memory, and a processor. The memory stores a program, and the processor invokes the program in the memory and controls the transceiver to receive or transmit signals so that the network device performs the method as described in any one of claims 18-32.

73. A network device, characterized in that, The device includes a transceiver, a memory, and a processor. The memory stores a program, and the processor invokes the program in the memory and controls the transceiver to receive or transmit signals so that the network device performs the method as described in any one of claims 33-35.

74. An apparatus, characterized in that, Includes a processor for calling a program from memory to cause the device to perform the method as described in any one of claims 1-35.

75. A chip, characterized in that, Includes a processor for calling a program from memory, causing a device on which the chip is mounted to perform the method as described in any one of claims 1-35.

76. A computer-readable storage medium, characterized in that, It contains a program that causes a computer to perform the method as described in any one of claims 1-35.

77. A computer program product, characterized in that, Includes a program that causes a computer to perform the method as described in any one of claims 1-35.

78. A computer program, characterized in that, The computer program causes the computer to perform the method as described in any one of claims 1-35.

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