Communication method and terminal device

Abstract

A communication method and a terminal device are provided. The method comprises: on the basis of a target TRP, a terminal device performs a handover to a target cell, wherein the target cell comprises a first TRP and a second TRP, the second TRP is a TRP associated with an early sync process, the first TRP is a TRP associated with a cell handover execution process, and the target TRP comprises the first TRP and / or the second TRP. The first TRP acquired by the terminal device in the early sync process may be different from the second TRP acquired by the terminal device in the cell handover process. In this case, the terminal device determines the target TRP from among the first TRP and the second TRP, and performs a handover to the target cell on the basis of a resource associated with the target TRP, thereby achieving a cell handover in a multi-TRP scenario.

Description

Communication methods and terminal equipment Technical Field

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

[0002] L1 / L2-triggered mobility (LTM) can be triggered by network devices. This involves the terminal device reporting the Layer 1 (L1) measurement results of candidate cells to the network device. Based on the received L1 measurement results, the network device triggers early synchronization, determines the target cell, and sends a cell handover command to the terminal device. To further enhance the robustness of the LTM process, terminal-triggered LTM, also known as conditional LTM (CLTM), can also be considered. CLTM may require the terminal device to autonomously trigger early synchronization, and handover execution may also be autonomously triggered by the terminal device. To enhance uplink coverage and transmission reliability, the aforementioned candidate cells may support multiple TRPs (mTRP). In this case, how to implement cell handover in multi-TRP scenarios becomes a problem that needs to be solved. Summary of the Invention

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

[0004] In a first aspect, a communication method is provided, comprising: a terminal device switching to a target cell based on a target TRP, wherein the target cell includes a first TRP and a second TRP, the second TRP being a TRP associated with an advance synchronization process, the first TRP being a TRP associated with a cell handover execution process, and the target TRP including the first TRP and / or the second TRP.

[0005] In a second aspect, a terminal device is provided, comprising: a transceiver unit, configured to hand over to a target cell based on a target TRP, wherein the target cell includes a first TRP and a second TRP, the second TRP being a TRP associated with an advance synchronization process, the first TRP being a TRP associated with a cell handover execution process, and the target TRP including the first TRP and / or the second TRP.

[0006] Thirdly, a terminal device is provided, including a transceiver, a memory, and a processor, wherein the memory is used to store a program, and the processor is used to call the program in the memory and control the transceiver to receive or send signals so that the terminal device performs the method as described in the first aspect.

[0007] Fourthly, an apparatus is provided, including a processor for calling a program from a memory to cause the apparatus to perform the method as described in the first aspect.

[0008] Fifthly, a chip is provided, including a processor for calling a program from memory, causing a device having the chip mounted to perform the method as described in the first aspect.

[0009] A sixth aspect provides a computer-readable storage medium having a program stored thereon that causes a computer to perform the method as described in the first aspect.

[0010] A seventh aspect provides a computer program product, including a program that causes a computer to perform the method as described in the first aspect.

[0011] Eighthly, a computer program is provided that causes a computer to perform the method as described in the first aspect.

[0012] In this embodiment of the application, the first TRP obtained by the terminal device during the advance synchronization process may be different from the second TRP obtained during the cell handover process. In this case, the terminal device determines the target TRP from the first TRP and the second TRP, and hands over to the target cell based on the resources associated with the target TRP, so that cell handover in the multi-TRP scenario can be realized. Attached Figure Description

[0013] Figure 1 is a system architecture example diagram of a wireless communication system applicable to embodiments of this application.

[0014] Figure 2 is a schematic diagram of the cell handover process across base stations.

[0015] Figure 3 is a schematic diagram of the condition switching process.

[0016] Figure 4 is a schematic diagram of LTM.

[0017] Figure 5 is a schematic diagram of the relevant fields involved in the LTM process execution phase in LTM.

[0018] Figure 6 is a flowchart illustrating the wireless communication method according to an embodiment of this application.

[0019] Figure 7 is a schematic diagram of the structure of the terminal device according to an embodiment of this application.

[0020] Figure 8 is a schematic diagram of a communication apparatus according to an embodiment of this application. Detailed Implementation

[0021] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0022] Wireless communication system

[0023] Figure 1 is an example diagram of the system architecture 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 can provide network coverage for a specific geographical area and can communicate with the terminal device 120 located within that coverage area. The terminal device 120 can access a network, such as a wireless network, through the network device 110. Optionally, the wireless communication system 100 may also include other network entities such as a network controller and a mobility management entity; this embodiment of the application does not limit this.

[0024] It should be understood that the technical solutions of the embodiments of this application can be applied to various communication systems, such as: fifth generation (5G) systems, new radio (NR), long term evolution (LTE) systems, LTE frequency division duplex (FDD) systems, LTE time division duplex (TDD) systems, etc. The technical solutions provided in this application can also be applied to future communication systems, such as sixth generation mobile communication systems, satellite communication systems, etc.

[0025] In this application embodiment, the terminal device may 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 apparatus. 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. Terminal devices can also be mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, self-driving, remote medical surgery, smart grids, transportation safety, smart cities, and smart homes. Optionally, terminal devices can act as base stations. For example, a terminal device can act as a dispatching entity, providing sidelink signals between terminal devices in vehicle-to-everything (V2X) or device-to-device (D2D) systems. For instance, cellular phones and cars communicate with each other using sidelink signals. Cellular phones and smart home devices communicate without relaying communication signals through base stations.

[0026] In this embodiment, the network device can be a device used to communicate with a terminal device. The network device can be an access network device or a wireless access network device. For example, the network device can be a base station. The term "base station" can broadly encompass various names as follows, or can be replaced by names such as: 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 entity, or a combination thereof. A base station can also refer to a communication module, modem, or chip installed within the aforementioned equipment or apparatus. A base station can also be a mobile switching center, or an entity that performs base station functions in device-to-device (D2D), vehicle-to-everything (V2X), and machine-to-machine (M2M) communications, a network-side device in a 6G network, or an entity that performs base station functions in future communication systems. A base station 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. A base station 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.

[0027] Furthermore, 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. In some deployments, network equipment can refer to a CU or DU; or, network equipment can include both CU and DU. Optionally, the base station may also include an AAU.

[0028] 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.

[0029] 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 such as a cloud platform.

[0030] Traditional switching process

[0031] Similar to LTE systems, NR systems support handover processes for connected terminal devices. When a terminal device using network services moves from one cell to another, or when issues such as adjustments to radio transmission service load, activation maintenance, or equipment failure occur, the system needs to transfer the communication link between the terminal device and the original cell to the new cell to ensure communication continuity and service quality; this is called a handover process.

[0032] As an example, Figure 2 shows a schematic diagram of the cell handover process across base stations, which generally includes some or all of the following steps.

[0033] In step 210, the serving base station or source base station (gNB) triggers handover based on the L3 measurement results reported by the terminal device and sends a handover request message to the target base station (gNB) through the Xn interface.

[0034] In step 220, the target base station receives a handover request message from the source base station and performs admission control.

[0035] In step 230, if the target base station decides to allow the terminal device to handover, the target base station sends a handover request acknowledge message to the source base station.

[0036] The target base station can provide its radio resource control (RRC) configuration and send it back to the source base station as part of the handover request confirmation message.

[0037] In step 240, the source base station sends an RRC reconfiguration message to the terminal device, instructing the terminal device to initiate a handover process and providing RRC configuration information for accessing the target base station.

[0038] In step 250, the terminal device performs a handover to the target base station.

[0039] In step 260, the terminal device connects to the target base station and sends an RRC reconfiguration complete message to the target base station.

[0040] In order to establish uplink synchronization between the terminal device and the target base station, the terminal device needs to initiate a random access procedure to the target base station.

[0041] The target base station mentioned above can also be replaced with the target cell, and the source base station mentioned above can also be replaced with the source cell.

[0042] Conditional handover (CHO)

[0043] The primary goal of conditional handover is to improve the reliability and robustness of user handover, addressing issues such as delayed handover due to excessive preparation time or handover failure caused by a sharp decline in source cell channel quality during the handover process. The core idea of ​​conditional handover is to pre-configure the handover command to the terminal device. When specific conditions are met, the terminal device can autonomously execute the configuration in the handover command and directly initiate handover access to the target cell that meets the conditions. Since the terminal device no longer triggers measurement reporting when the handover conditions are met, and the terminal device has already obtained the configuration in the handover command, the problems of measurement reporting and incorrect reception of the handover command are solved. Conditional handover can significantly improve the handover success rate, especially in high-speed mobile scenarios or scenarios where signal fading occurs rapidly in the handover zone. As an example, the basic process of conditional handover is shown in Figure 3.

[0044] Typically, the handover process can be divided into three stages: handover preparation, handover execution, and handover completion. The process shown in Figure 2 can be executed by the terminal equipment, the source gNB (the base station corresponding to the source cell), the target gNB (the base station corresponding to the target cell), other potential target gNBs, the access and mobility management function (AMF), and the user plane function (UPF) (UPF(s)). For example, the source gNB can be the source gNB.

[0045] Phase 1: Switchover Preparation (Steps 1-7)

[0046] In step 1, measurement control and reporting are performed between the source base station and the terminal device. Specifically, the source base station triggers the terminal device to perform neighbor cell measurements, and the terminal device can measure the neighbor cells and report the measurement results to the source base station.

[0047] Before step 1, user data can be transmitted between the terminal device and the source base station, and user data can be transmitted between the source base station and the UPF.

[0048] As shown in Figure 3, the first stage may also include step 0 before step 1. In step 0, the AMF provides mobility control information.

[0049] In step 2, the source base station evaluates the measurement results reported by the terminal device and decides whether to trigger a handover (CHO decision).

[0050] In step 3, if the source base station decides to trigger a handover, it sends a handover request message to the target base station and other alternative target base stations.

[0051] In step 4, after the target base station and other alternative target base stations receive the handover request message sent by the source base station, they can start admission control based on the service information carried by the source base station.

[0052] In step 5, if the target base station decides to allow the terminal device to handover, the target base station sends a handover request acknowledgement message to the source base station. Similarly, other alternative target base stations may also send handover request acknowledgement messages to the source base station.

[0053] In step 6, the source base station sends an RRC reconfiguration message for the alternative target base station to the terminal device.

[0054] In step 7, the terminal device sends an RRC reconfiguration complete message to the source base station.

[0055] Phase Two: Switching Execution (Steps 7a-8)

[0056] After step 7, the terminal device can evaluate the CHO conditions.

[0057] In step 7a, the terminal device sends an early status transfer message to other candidate target base stations based on the evaluation results.

[0058] After step 7a, the terminal device detaches from the old cell and synchronizes with the new cell.

[0059] In step 8, the conditional handover is completed.

[0060] Phase 3: Switching Completed (Steps 8a to 8c)

[0061] In step 8a, the target base station sends a handover success message to the source base station.

[0062] In step 8b, the source base station can forward buffered data, in-transmission data packets, and data sequence numbers (SN) to the target base station via SN status transfer messages.

[0063] After step 8b, user data can be transmitted between the terminal device and the target base station.

[0064] In step 8c, the source base station may also send a handover cancel message to the target base station and other alternative target base stations.

[0065] LTM process

[0066] The handover process is typically triggered by Layer 3 (L3) signaling, such as RRC Reconfiguration messages. To further reduce the latency of L3 handover, the NR R18 Mobility Project proposed L1 / L2-triggered cell handover, or LTM. As an example, Figure 4 illustrates the basic LTM process, which includes some or all of the following steps.

[0067] As shown in Figure 4, the LTM process can include the LTM preparation phase, the LTM execution phase, and the LTM completion phase.

[0068] Steps 410 and 430 in Figure 4 belong to the LTM preparation stage.

[0069] The terminal device processes the RRC connection state. At this time, the terminal device can perform measurements.

[0070] In step 410, the terminal device reports the measurement results to the network device. These measurement results may be, for example, L3 measurement results. The network device can then determine whether to initiate an LTM procedure and trigger candidate cell preparation based on the measurement results reported by the terminal device.

[0071] In step 420, the network device sends an RRC message to the terminal device that includes the LTM candidate cell configuration (or LTM candidate configuration, LTM configuration). For example, the network device may send an RRC reconfiguration message to the terminal device to indicate the LTM candidate cell configuration.

[0072] The LTM candidate cell configuration sent by the network device to the terminal device may include configuration information for one or more candidate cells, such as configuration information for one or more primary cells, and configuration information for one or more primary-secondary cells or one or more secondary cells. This configuration information is used by the terminal device to perform early synchronization processes, such as early uplink synchronization and / or early downlink synchronization.

[0073] In step 430, after receiving the LTM candidate cell configuration, the terminal device stores the LTM candidate cell configuration and sends an RRC reconfiguration complete message to the network device.

[0074] Before receiving an LTM cell handover command, the terminal device can perform synchronization with the candidate cell in advance to shorten the interruption latency during the handover process. This process can be regarded as an advance synchronization phase, or an early synchronization phase. Here, the synchronization may include downlink synchronization (see step 440a) and / or uplink synchronization (see step 440b).

[0075] As an example, the process of a terminal device performing uplink synchronization for a candidate cell in advance can include the following two methods: 1) The terminal device calculates the timing advance (TA) value of the candidate cell based on the TA value of the current serving cell. For example, it estimates the TA value of the candidate cell based on the difference between the downlink reference signal delays of the serving cell and the candidate cell; 2) The serving cell triggers the terminal device to send a preamble to the candidate cell via a physical downlink control channel (PDCCH) order. The candidate cell receives the preamble sent by the terminal device, calculates the TA value of the terminal device in that cell, and informs the serving cell of the TA value and the identification information (TAG ID) of its associated timing advance group (TAG), so that the serving cell can include it in the cell handover command. If the advance synchronization process is successfully executed, step 470 below can be skipped. Therefore, this process can also be called RACH-less LTM. If the early synchronization process fails due to reasons such as the location of the terminal device moving or signal delay, and the terminal device does not obtain the TA value of the target cell, then step 470 below needs to be executed.

[0076] Steps 450, 460 and 470 in Figure 4 belong to the LTM execution phase, with step 470 being optional.

[0077] In step 450, the terminal device performs L1 measurement on each candidate cell and reports the L1 measurement results to the network device.

[0078] After receiving the L1 measurement results reported by the terminal device, the network device can determine the target cell based on the L1 measurement results.

[0079] In step 460, the network device sends a cell switch command to the terminal device to instruct the terminal device to switch to the target cell. For example, the cell switch command can be carried in the medium access control element (MAC CE), that is, the cell switch command is LTM cell switch MAC CE.

[0080] After receiving the cell handover command, the terminal device detaches from the source cell and applies the target cell's configuration, i.e., the target configuration. In R18 LTM, candidate cells can also support dual TAs (Multiple Input Multiple Output, MIMO), i.e., MIMO 2TA. In this scenario, the terminal device needs to determine which TAG ID corresponds to the TA in the cell handover command. This information is determined by the tag identifier (tag ID) associated with the transmission configuration indication (TCI) state ID and the time to trigger for PSCell release, i.e., tag-Id-tpr. For example, relevant fields can be found in Figure 5, including target config ID, timing advance command, TCI state ID, uplink TCI state ID, random access preamble index, synchronization signal block / physical broadcast channel block (SS / PBCH block, SSB) index, physical random access channel mask index, and repetition number.

[0081] The terminal device determines whether to perform RACH-less LTM (if the target cell's TA value is available) or RACH-based LTM (if the target cell's TA value is unavailable) based on whether the target cell's TA value is available. The target cell's TA value can be calculated by the terminal device or obtained by receiving a cell handover command; that is, the TA value carried in the cell handover command is not FFF.

[0082] If the terminal device does not have a valid TA for the target cell, the terminal device executes step 470 during the LTM execution phase. In step 470, the terminal device executes the random access channel (RACH) procedure to initiate random access to the target cell.

[0083] Step 480 in Figure 4 belongs to the LTM completion stage.

[0084] In step 480, the terminal device indicates to the network device that LTM is complete.

[0085] Multi-TRP (mTRP)

[0086] Release 17 MIMO supports repetition of the physical uplink control channel (PUCCH) / physical uplink shared channel (PUSCH) based on the mTRP, aiming to enhance uplink coverage and transmission reliability. Terminal equipment needs to send PUCCH / PUSCH carrying the same content to different TRPs. During this process, the terminal equipment uses the same TA value to send uplink data to different TRPs. Release 18 MIMO defines a mechanism for multiple antenna panels of a terminal equipment to simultaneously transmit PUCCH / PUSCH to multiple TRPs, and supports TRP-specific TA acquisition and indication. That is, when the serving cell of a terminal equipment includes two TRPs, it can be assigned two TAGs, with each TAG corresponding to one TRP.

[0087] The R18 mobility topic mainly discusses LTM triggered by the network side, in which the terminal device reports the L1 measurement results of candidate cells (or beams) to the network, the network device triggers the advance synchronization process based on the received L1 measurement results, determines the target cell, and sends a cell handover command to the terminal device through, for example, MAC CE.

[0088] To further enhance the robustness of the LTM process, the R19 study considered terminal device-triggered LTM, i.e., CLTM. R18 LTM supports early uplink synchronization between the terminal device and the candidate cell. This early uplink synchronization process is triggered by a PDCCH order sent by the source base station. The terminal device sends a preamble to the candidate cell based on a Physical Downlink Control Channel (PDCCH) order. Unlike the traditional random access procedure, the terminal device does not need to listen for the random access response (RAR) after sending the preamble. During the LTM execution phase, the network device sends the target cell's TA information (e.g., TA value and corresponding TAG ID) to the terminal device via an LTM cell handover command. From the terminal device's perspective, it does not need to know which TAG under the candidate cell it is sending a preamble to during the early synchronization process. The CLTM process may require the terminal device to autonomously trigger early synchronization and support RAR reception; the execution of LTM is also autonomously triggered by the terminal device. Furthermore, LTM's cell switch command also supports instructing Contention-Free Random Access (CFRA) resources for terminal devices to quickly perform the handover process.

[0089] When a candidate cell supports mTRP, since the resources involved in the LTM process (e.g., TA indication, TCI state, RACH resources, etc.) are configured for each TRP, if the resources selected by the terminal device are associated with different TRPs than the resources indicated by the network device, the terminal device needs to align the TRPs selected in different processes (e.g., advance synchronization (including uplink synchronization and / or downlink synchronization) and handover execution). For example, if the TAG / TCI state selected by the terminal device is associated with a different TRP than the CFRA resource indicated by the network device, TRP alignment is required; similarly, if the TCI / CFRA resources / TA determined during the advance uplink synchronization process are associated with different TRPs than those determined during the handover execution process, TRP alignment is required; and similarly, if the TCI / CFRA resources determined during the advance downlink synchronization process are associated with different TRPs than those determined during the handover execution process, TRP alignment is required. The process of aligning TRPs refers, for example, to the process by which the terminal device determines which TRP to perform cell handover on.

[0090] Therefore, this application provides a communication method in which the TRP (hereinafter referred to as the first TRP) obtained by the terminal device during the advance synchronization process may be different from the TRP (hereinafter referred to as the second TRP) obtained during the cell handover process. In this case, the terminal device determines the target TRP from the first TRP and the second TRP, and hands over to the target cell based on the resources associated with the target TRP, so that cell handover in the multi-TRP scenario can be realized.

[0091] The cell handover in this application embodiment may include one or more of the following: LTM handover, CHO, CLTM (including MCG LTM and / or SCG LTM), conditional primary / secondary cell addition (CPA), conditional primary / secondary cell change (CPC), and subsequent primary / secondary cell addition / change (SCPAC). Furthermore, the technical solutions in this application embodiment can support inter-CU and / or intra-CU scenarios.

[0092] The embodiments of this application will be described in detail below with reference to Figure 6.

[0093] Figure 6 is a flowchart illustrating a wireless communication method provided in an embodiment of this application. The method 600 shown in Figure 6 can be executed by a terminal device. The terminal device can be, for example, the terminal device 120 shown in Figure 1.

[0094] Referring to Figure 6, in step 610, the terminal device switches to the target cell based on the target TRP.

[0095] The target cell includes a first TRP and a second TRP. The second TRP is the TRP associated with the pre-synchronization process, and the first TRP is the TRP associated with the cell handover execution process. The target TRP determined by the terminal device can be the first TRP, or the target TRP can be the second TRP, or the target TRP can include both the first and second TRPs.

[0096] The TRP associated with the advance synchronization process refers to, for example, the TRP selected during the advance synchronization process, or the TRP associated with the resources acquired during the advance synchronization process. The TRP associated with the advance synchronization process can be determined based on instructions from the network device or determined autonomously by the terminal device. Similarly, the TRP associated with the cell handover execution process refers to, for example, the TRP selected during the cell handover execution process, or the TRP associated with the resources acquired during the cell handover execution process. The TRP associated with the cell handover execution process can be determined based on information carried in the cell handover command sent by the network device or determined by the terminal device based on conditional selection.

[0097] Taking Figure 4 as an example, the advance synchronization process can be the advance synchronization phase shown in Figure 4, and the cell handover execution process can be the LTM execution phase shown in Figure 4. The second TRP associated with the advance synchronization phase may be determined by the network device or the terminal device; the first TRP associated with the cell handover execution process may be determined by the network device or the terminal device.

[0098] It should be noted that the number of TRPs associated with the cell handover execution process or the advance synchronization process can be one or more. Among them, the first TRP is the TRP associated with the cell handover execution process, but it is not excluded that the cell handover execution process may also be associated with a second TRP and / or other TRPs; the second TRP is the TRP associated with the advance synchronization process, but it is not excluded that the advance synchronization process may also be associated with the first TRP and / or other TRPs.

[0099] In this embodiment of the application, the advance synchronization process includes an uplink synchronization process and / or a downlink synchronization process. For example, the uplink synchronization process includes obtaining the TA; and the downlink synchronization process may include obtaining downlink synchronization information (or downlink timing) and / or activating the TCI state.

[0100] When the target cell supports multiple TRPs, the first and second TRPs selected at different stages may be different. Therefore, the terminal device needs to specify which TRP associated with the resource should be used to switch to the target cell during the cell handover process.

[0101] After determining the target TRP, the terminal device can hand over to the target cell based on the target TRP. For example, the handover of the terminal device to the target cell based on the target TRP may include the handover of the terminal device to the target cell based on the resources associated with the target TRP. The resources associated with the TRP (e.g., the target TRP, the first TRP, the second TRP) in the embodiments of this application may include one or more of the following: beam, SSB, TCI status, sounding reference signal (SRS), tracking reference signal (TRS), channel state information-reference signal (CSI-RS), SSB relative index (SSBRI), channel state information relative index (CSIRI), control resource set (CORESET) pool information (e.g., CORESET pool index), physical cell identity (PCI), additional PCI, TA information (e.g., TAG ID), and RACH resources.

[0102] As an example, a terminal device can send an RRC reconfiguration complete message to the target TRP to hand over to the target cell; for another example, the terminal device can perform a random access procedure based on the RACH resources associated with the target TRP to hand over to the target cell; for yet another example, the terminal device can hand over to the target cell based on the beam (e.g., SSB and / or TCI status) associated with the target TRP; or for yet another example, the terminal device can hand over to the target cell based on the synchronization information (e.g., TCI status and / or TA information) associated with the target TRP. The handover process may include one or more steps, such as initiating access to the target cell, synchronizing with the target cell, etc.; or, when synchronization and access operations are not required, the terminal device can directly send an RRC reconfiguration complete message to the target TRP to complete the handover to the target cell. It should be noted that handover to the target cell based on the target TRP can mean that the terminal device handovers to the target cell solely based on the target TRP, or it can mean that the terminal device prioritizes handover to the target cell based on the target TRP. For example, if a terminal device identifies a target TRP as the first TRP, it will prioritize initiating access or synchronization with the first TRP. However, it may subsequently initiate access or synchronization with the second TRP.

[0103] In this application embodiment, the following four scenarios may be involved: 1) the advance synchronization process is triggered by the terminal device and the cell handover process is triggered by the network device; 2) the advance synchronization process is triggered by the terminal device and the cell handover process is triggered by the terminal device; 3) the advance synchronization process is triggered by the network device and the cell handover process is triggered by the terminal device; 4) the advance synchronization process is triggered by the network device and the cell handover process is triggered by the network device.

[0104] The pre-synchronization process, triggered by the terminal device, can be implemented in various ways. For example, the pre-synchronization process may be triggered by the terminal device based on its internal implementation, or in other words, it may be triggered autonomously by the terminal device; another example is that the pre-synchronization process may be triggered by the terminal device based on predetermined conditions. These predetermined conditions can be configured or pre-configured by the network device. Optionally, these predetermined conditions may be associated with one or more of the following: L1 measurement-related conditions; L3 measurement-related conditions; conditions related to the measurement results of the serving cell (or serving beam); and conditions related to the measurement results of candidate cells (or candidate beams). For example, based on whether the measurement results of the serving beam and / or candidate beams meet the configured conditions, the terminal device determines which candidate cell to initiate the pre-uplink synchronization and / or pre-downlink synchronization process to. For instance, the terminal device may initiate the pre-uplink synchronization and / or pre-downlink synchronization process to the candidate cell with the best measurement results.

[0105] The advance synchronization process, triggered by the network device, can be implemented in several ways. For example, it can be triggered by the network device sending a PDCCH order; another example is that it can be triggered by the network device sending a MAC CE; yet another example is that it can be triggered by an indication message sent by the network device, which can instruct the terminal device to perform advance synchronization based on its internal implementation.

[0106] In a cell handover process triggered by a network device, the network device sends a cell handover command to the terminal device, instructing the terminal device to perform a cell handover. Upon receiving the cell handover command, the terminal device performs a handover to the target cell. Optionally, the handover command may carry related resources, such as TA information, TCI status, CFRA resources, etc.

[0107] For the cell handover process triggered by the terminal device, the terminal device can determine to hand over to the target cell based on conditions. Here, the conditions may refer to, for example, L1 measurement conditions, L3 measurement conditions, conditions involved in CHO, etc., and this application embodiment does not limit them.

[0108] The terminal device selects a second TRP during the advance synchronization process. For example, the second TRP may be indicated by the network device, such as the network device explicitly instructing the terminal device to perform the advance synchronization process on the second TRP; or the second TRP may be the default TRP requiring advance synchronization; or the second TRP may be determined based on priority information, such as the second TRP having a higher priority than the first TRP, in which case the advance synchronization process is performed on the second TRP; or the second TRP may be determined based on the terminal device's measurement results, such as the second TRP being the candidate beam association TRP with the best measurement results; or the second TRP may be a pre-agreed TRP requiring advance synchronization; or the second TRP may be a TRP determined by the terminal device based on its internal implementation.

[0109] It should be noted that the terminal device may perform the advance synchronization process only to the second TRP, or the terminal device may perform the advance synchronization process to multiple or all TRPs of the candidate cell. Specifically, performing the advance synchronization process to the second TRP may refer to the terminal device performing the advance synchronization process based on the resources associated with the second TRP.

[0110] In one implementation, the terminal device may determine the target TRP based on one or more of the following information: a second TRP associated with an advance synchronization process executed by the terminal device (e.g., an advance synchronization process triggered by a network device); a second TRP associated with an advance synchronization process triggered by the terminal device; a second TRP associated with the TCI status and / or TA information indicated in the synchronization message during the advance synchronization process; a second TRP associated with the TCI status activated and / or the TA information acquired during the advance synchronization process triggered by the terminal device; a TRP associated with a cell handover command during the cell handover execution process; a second TRP associated with the TCI status and / or TA information indicated in the cell handover command; a TRP associated with CFRA resources in the cell handover command; identification information of the target cell; and priority information of the TRP.

[0111] The following describes how a terminal device determines a target TRP, taking as examples situations where the terminal device has an available TA, available CFRA resources, and an activated TCI state. This application does not limit the method of obtaining available resources (e.g., available TA, available CFRA resources, activated TCI state). For example, available resources (e.g., acquired resources) can be determined by the terminal device (e.g., determined by the terminal device based on measurement results during advance synchronization), or sent by the network device (e.g., the network device displays and indicates this to the terminal device through advance synchronization messages such as TCI state activation / deactivation of MAC CE, TA indicating MAC CE), or carried in cell handover commands, candidate cell configurations, or LTM configurations.

[0112] Terminal devices have available TAs

[0113] In one implementation, the target TRP is the first TRP. That is, when the pre-synchronization process and the cell handover execution process are associated with different TRPs, the terminal device hands over to the target cell based on the first TRP associated with the cell handover execution process. For example, the terminal device hands over to the target cell based on the first TRP associated with the resources indicated in the cell handover command (e.g., TA information, TCI status, or CFRA resources).

[0114] In one implementation, the target TRP is the second TRP. That is, when the advance synchronization process and the cell handover execution process are associated with different TRPs, the terminal device hands over to the target cell based on the second TRP associated with the advance synchronization process. For example, the terminal device hands over to the target cell based on the second TRP associated with resources (e.g., TA information, TCI status, or CFRA resources) acquired during the advance synchronization process.

[0115] In one implementation, the target TRP may include a first TRP and a second TRP. In this case, the terminal device may first synchronize with the first TRP based on the resources associated with the first TRP, and then synchronize with the second TRP based on the resources associated with the second TRP; or, the terminal device may first synchronize with the second TRP based on the resources associated with the second TRP, and then synchronize with the first TRP based on the resources associated with the first TRP.

[0116] In one implementation, the target TRP is the TRP associated with an available TA in either the first or second TRP. For example, if the cell handover command during the handover process includes the TA associated with the first TRP, and the terminal device has obtained the TA associated with the second TRP during the pre-synchronization process, the terminal device can handover to the target cell based on either the first or second TRP. Alternatively, if the cell handover command during the handover process includes the TA associated with the first TRP, and the terminal device has not obtained the TA associated with the second TRP during the pre-synchronization process, the terminal device can handover to the target cell based on the first TRP. Or, if the cell handover command during the handover process does not include the TA associated with the first TRP, but the terminal device has obtained the TA associated with the second TRP during the pre-synchronization process, the terminal device can handover to the target cell based on the second TRP.

[0117] In one implementation, the target TRP is the TRP with the same PCI as the target cell that is part of the first TRP and the second TRP. For example, when the advance synchronization process and the cell handover execution process are associated with different TRPs, if the PCI corresponding to the first TRP is different from the PCI of the target cell, and the PCI corresponding to the second TRP is the same as the PCI of the target cell, the terminal device can handover to the target cell based on the second TRP. As another example, when the advance synchronization process and the cell handover execution process are associated with different TRPs, if the PCI corresponding to the first TRP is the same as the PCI of the target cell, and the PCI corresponding to the second TRP is different from the PCI of the target cell, the terminal device can handover to the target cell based on the first TRP.

[0118] In one implementation, the target TRP is the higher-priority TRP between the first and second TRPs. Priorities can be configured for different TRPs. When different TRPs are associated during the pre-synchronization process and the cell handover execution process, the terminal device can handover to the target cell based on the higher-priority TRP. For example, if the first TRP has a higher priority than the second TRP, the terminal device handovers to the target cell based on the first TRP; if the second TRP has a higher priority than the first TRP, the terminal device handovers to the target cell based on the second TRP.

[0119] In one implementation, the target TRP is the TRP associated with an activated TCI state in either the first TRP or the second TRP. For example, during cell handover execution, a cell handover command indicates the TCI state associated with the first TRP, and the terminal device acquires the TA associated with the second TRP during the pre-synchronization process. The terminal device can then handover to the target cell based on the first TRP. Alternatively, during cell handover execution, a cell handover command indicates the TA associated with the first TRP, and the terminal device activates the TCI state associated with the second TRP during the pre-synchronization process. The terminal device can then handover to the target cell based on the second TRP. Again, during cell handover execution, a cell handover command indicates the TCI state associated with the first TRP, and the terminal device activates the TCI state associated with the second TRP during the pre-synchronization process. The terminal device can then handover to the target cell based on the second TRP.

[0120] In one implementation, the target TRP is the TRP among the first TRP and the second TRP that satisfies the cell handover conditions. For example, when the pre-synchronization process and the cell handover execution process are associated with different TRPs, if the measurement results of the beam associated with the first TRP (e.g., RSRP, RSRQ, SINR) satisfy the cell handover conditions, and the measurement results of the beam associated with the second TRP (e.g., RSRP, RSRQ, SINR) do not satisfy the cell handover conditions, the terminal device hands over to the target cell based on the first TRP. As another example, when the pre-synchronization process and the cell handover execution process are associated with different TRPs, if the measurement results of the beam associated with the first TRP do not satisfy the cell handover conditions, but the measurement results of the beam associated with the second TRP do satisfy the cell handover conditions, the terminal device hands over to the target cell based on the second TRP.

[0121] The terminal device has available CFRA resources.

[0122] In one implementation, the target TRP is the first TRP. That is, when the pre-synchronization process and the cell handover execution process are associated with different TRPs, the terminal device hands over to the target cell based on the first TRP associated with the cell handover execution process. For example, the terminal device hands over to the target cell based on the first TRP associated with the resources indicated in the cell handover command (e.g., TA information, TCI status, or CFRA resources).

[0123] In one implementation, the target TRP is the second TRP. That is, when the advance synchronization process and the cell handover execution process are associated with different TRPs, the terminal device hands over to the target cell based on the second TRP associated with the advance synchronization process. For example, the terminal device hands over to the target cell based on the second TRP associated with resources (e.g., TA information, TCI status, or CFRA resources) acquired during the advance synchronization process.

[0124] In one implementation, the target TRP is the TRP associated with available CFRA resources in the first and second TRPs. For example, if the cell handover command during the cell handover process includes the CFRA resources associated with the first TRP, and the terminal device activates the TCI state associated with the second TRP during the advance synchronization process, the terminal device can handover to the target cell based on the first TRP. As another example, if the cell handover command during the cell handover process includes the CFRA resources associated with the first TRP, and the terminal device does not acquire the TA associated with the second TRP during the advance synchronization process, the terminal device can handover to the target cell based on the first TRP. Yet another example, if the cell handover command during the cell handover process includes the TCI state associated with the first TRP, and the candidate cell configuration includes the CFRA resources associated with the second TRP, the terminal device can handover to the target cell based on the second TRP.

[0125] In one implementation, the target TRP is the TRP with the same PCI as the target cell that is part of the first TRP and the second TRP. For example, when the advance synchronization process and the cell handover execution process are associated with different TRPs, if the PCI corresponding to the first TRP is different from the PCI of the target cell, and the PCI corresponding to the second TRP is the same as the PCI of the target cell, the terminal device can handover to the target cell based on the second TRP. As another example, when the advance synchronization process and the cell handover execution process are associated with different TRPs, if the PCI corresponding to the first TRP is the same as the PCI of the target cell, and the PCI corresponding to the second TRP is different from the PCI of the target cell, the terminal device can handover to the target cell based on the first TRP.

[0126] In one implementation, the target TRP is the higher-priority TRP between the first and second TRPs. Priorities can be configured for different TRPs. When different TRPs are associated during the pre-synchronization process and the cell handover execution process, the terminal device can handover to the target cell based on the higher-priority TRP. For example, if the first TRP has a higher priority than the second TRP, the terminal device handovers to the target cell based on the first TRP; if the second TRP has a higher priority than the first TRP, the terminal device handovers to the target cell based on the second TRP.

[0127] In one implementation, the target TRP is the TRP associated with an activated TCI state in either the first or second TRP. For example, during cell handover execution, a cell handover command indicates the TCI state associated with the first TRP, and the terminal device obtains the TA associated with the second TRP during the pre-synchronization process. The terminal device can then handover to the target cell based on the first TRP. As another example, during cell handover execution, a cell handover command indicates the CFRA resource associated with the first TRP, and the terminal device obtains the TCI state associated with the second TRP during the pre-synchronization process. The terminal device can then handover to the target cell based on the second TRP.

[0128] In one implementation, the target TRP is the TRP among the first TRP and the second TRP that satisfies the cell handover conditions. For example, when the pre-synchronization process and the cell handover execution process are associated with different TRPs, if the measurement results of the beam associated with the first TRP (e.g., RSRP, RSRQ, SINR) satisfy the cell handover conditions, and the measurement results of the beam associated with the second TRP (e.g., RSRP, RSRQ, SINR) do not satisfy the cell handover conditions, the terminal device hands over to the target cell based on the first TRP. As another example, when the pre-synchronization process and the cell handover execution process are associated with different TRPs, if the measurement results of the beam associated with the first TRP do not satisfy the cell handover conditions, but the measurement results of the beam associated with the second TRP do satisfy the cell handover conditions, the terminal device hands over to the target cell based on the second TRP.

[0129] The terminal device has an activated TCI status.

[0130] In one implementation, the target TRP is the first TRP. That is, when the pre-synchronization process and the cell handover execution process are associated with different TRPs, the terminal device hands over to the target cell based on the first TRP associated with the cell handover execution process. For example, the terminal device hands over to the target cell based on the first TRP associated with the resources indicated in the cell handover command (e.g., TA information, TCI status, or CFRA resources).

[0131] In one implementation, the target TRP is the second TRP. That is, when the advance synchronization process and the cell handover execution process are associated with different TRPs, the terminal device hands over to the target cell based on the second TRP associated with the advance synchronization process. For example, the terminal device hands over to the target cell based on the second TRP associated with resources (e.g., TA information, TCI status, or CFRA resources) acquired during the advance synchronization process.

[0132] In one implementation, the target TRP may include a first TRP and a second TRP. In this case, the terminal device may first synchronize with the first TRP based on the resources associated with the first TRP, and then synchronize with the second TRP based on the resources associated with the second TRP; or the terminal device may first synchronize with the second TRP based on the resources associated with the second TRP, and then synchronize with the first TRP based on the resources associated with the first TRP.

[0133] In one implementation, the target TRP is the TRP associated with an activated TCI state in either the first or second TRP. For example, if a cell handover command during the handover process activates the TCI state associated with the first TRP, and the terminal device did not acquire the TA associated with the second TRP during the pre-synchronization process, the terminal device can handover to the target cell based on the first TRP. Alternatively, if a cell handover command during the handover process does not indicate the TA associated with the first TRP, and the terminal device activated the TCI state associated with the second TRP during the pre-synchronization process, the terminal device can handover to the target cell based on the second TRP.

[0134] In one implementation, the target TRP is the TRP among the first TRP and the second TRP that satisfies the cell handover conditions. For example, when the pre-synchronization process and the cell handover execution process are associated with different TRPs, if the measurement results of the beam associated with the first TRP (e.g., RSRP, RSRQ, SINR) satisfy the cell handover conditions, and the measurement results of the beam associated with the second TRP (e.g., RSRP, RSRQ, SINR) do not satisfy the cell handover conditions, the terminal device hands over to the target cell based on the first TRP. As another example, when the pre-synchronization process and the cell handover execution process are associated with different TRPs, if the measurement results of the beam associated with the first TRP do not satisfy the cell handover conditions, but the measurement results of the beam associated with the second TRP do satisfy the cell handover conditions, the terminal device hands over to the target cell based on the second TRP.

[0135] In one implementation, the target TRP is the higher-priority TRP between the first and second TRPs. Priorities can be configured for different TRPs. When different TRPs are associated during the pre-synchronization process and the cell handover execution process, the terminal device can handover to the target cell based on the higher-priority TRP. For example, if the first TRP has a higher priority than the second TRP, the terminal device handovers to the target cell based on the first TRP; if the second TRP has a higher priority than the first TRP, the terminal device handovers to the target cell based on the second TRP.

[0136] Optionally, priorities can be set for the various methods used to determine the target TRP, so that the target TRP is determined in order of priority. For example, if the target TRP cannot be determined based on a higher priority method (e.g., both the first TRP and the second TRP meet the requirements and the target TRP is not allowed to include both the first TRP and the second TRP), the target TRP can be determined using a method with the next lower priority.

[0137] It should be noted that the target TEP determined using the above method may include a first TRP and a second TRP. For example, when determining the target TRP based on available TAs, both the first TRP and the second TRP are associated with TAs; or when determining the target TRP based on available TCIs, both the first TRP and the second TRP are associated with TCI states; or when determining the target TRP based on the target cell's PCI, the PCIs corresponding to both the first TRP and the second TRP are the same as the target cell's PCI. In this case, the terminal device can initiate access or synchronization to the first TRP and the second TRP respectively. For example, the terminal device first initiates access or synchronization to the first TRP based on the resources associated with the first TRP, and then initiates access or synchronization to the second TRP based on the resources associated with the second TRP; or, for example, the terminal device first initiates access or synchronization to the second TRP based on the resources associated with the second TRP, and then initiates access or synchronization to the first TRP based on the resources associated with the first TRP.

[0138] In other implementations, if the cell handover command includes resources associated with different TRPs, or if the terminal device autonomously acquires (e.g., during pre-synchronization) resources associated with different TRPs, and all the resources in each TRP satisfy the conditions that the target TRP should meet, then the terminal device can initiate access or synchronization to different TRPs sequentially. For example, if the cell handover command during the cell handover process includes two TAs, the terminal device can initiate access or synchronization to the TRP associated with one of the TAs, or the terminal device can sequentially initiate access or synchronization to different TRPs associated with the two TAs. As another example, if the terminal device autonomously acquires two TAs, the terminal device can initiate access or synchronization to the TRP associated with one of the TAs, or the terminal device can sequentially initiate access or synchronization to different TRPs associated with the two TAs.

[0139] In one implementation, if the target TRP is the first TRP, the terminal device can also send second information. This second information includes the TA and / or TCI status associated with the second TRP. This second information is used for subsequent access or synchronization between the terminal device and the second TRP. By sending the second information to the network (e.g., the first TRP and / or the second TRP), the terminal device informs the network that the other TRP has an acquired TA and / or an activated TCI status, thereby avoiding redundant procedures. If the other TRP does not have an acquired TA and an activated TCI status, the network can trigger a synchronization process to acquire the corresponding TA or activate the TCI status.

[0140] The embodiments of this application are described in more detail below with reference to specific examples, such as Embodiment 1, Embodiment 2, and Embodiment 3. It is understood that Embodiments 1, 2, and 3 are merely for the purpose of assisting those skilled in the art in understanding the embodiments of this application, and are not intended to limit the embodiments of this application to the specific numbers or scenarios illustrated. Those skilled in the art can obviously make various equivalent modifications or variations based on Embodiments 1, 2, and 3, and such modifications or variations also fall within the scope of the embodiments of this application.

[0141] Example 1: The terminal device triggers the advance synchronization process, and the network device triggers the cell handover execution process.

[0142] The terminal device receives configuration information sent by the network device. This configuration information includes candidate cell configuration, which is used by the terminal device to perform cell handover subsequently. Furthermore, this configuration information also includes advance synchronization configuration, which is used by the terminal device to perform the advance synchronization process.

[0143] The terminal device performs an advance synchronization process based on the advance synchronization configuration. This advance synchronization process includes advance uplink synchronization and / or advance downlink synchronization. Advance uplink synchronization includes, for example, obtaining uplink TA, and advance downlink synchronization includes, for example, obtaining downlink timing and / or activating TCI status.

[0144] The early synchronization process is triggered by the terminal device. In one implementation, the terminal device can trigger it based on conditions, which can be configured by the network device. For example, these conditions could be L1 measurement-related conditions, L3 measurement-related conditions, conditions related to the measurement results of the serving cell (or serving beam), or conditions related to the measurement results of a candidate cell (or candidate beam). The terminal device can determine which candidate cell or candidate beam to initiate the early uplink synchronization process and / or early downlink synchronization process based on whether the measurement results of the serving beam and / or candidate beam meet the requirements. Alternatively, the terminal device can initiate the early uplink synchronization process and / or early downlink synchronization process based on the currently optimal candidate cell or candidate beam. In another implementation, the terminal device autonomously triggers TA measurements based on its internal implementation, where the autonomous triggering of TA measurements by the terminal device can be indicated, for example, by the network device.

[0145] The terminal device determines the second TRP in one or more of the following ways during the advance synchronization process:

[0146] a) Based on the network device configuration, for example, the network device indicates which TRP the advance synchronization process is initiated to;

[0147] b) Based on the priority or TRP defined by the standard, for example, determining to initiate early synchronization to the second TRP based on priority information, or by default initiating early synchronization only to the second TRP or at least to the second TRP;

[0148] c) Determined based on measurement results, for example, the second TRP is the TRP that the terminal device selects as the optimal candidate beam association based on the measurement results;

[0149] d) Determined based on the internal implementation of the terminal device;

[0150] e) The terminal device performs an advance synchronization process with two or all TRPs of the candidate cell.

[0151] After the terminal device determines the second TRP, it performs an advance synchronization process based on the resources associated with the second TRP, such as the TA and / or TCI status associated with the second TRP.

[0152] The cell handover process is triggered by network devices. The network device sends a cell handover command to the terminal device, which then receives the command and executes the cell handover. The process of the terminal device executing the cell handover may include, for example:

[0153] a) The cell handover command includes a TA, and the TA is associated with the first TRP.

[0154] The terminal device performs cell handover based on the first TRP; or,

[0155] The terminal device performs cell handover based on the second TRP (there is an available TA); or,

[0156] The terminal device determines whether to perform cell handover based on the first TRP or the second TRP based on the PCI of the target cell. For example, if the PCI associated with the first TRP is different from the PCI of the target cell, but the PCI associated with the second TRP is the same as the PCI of the target cell, the terminal device performs cell handover based on the second TRP; or...

[0157] If the TA in the cell handover command is associated with the second TRP, that is, the second TRP is the same as the first TRP, the terminal device performs cell handover based on the first TRP; or,

[0158] If the TA in the cell handover command is associated with two TRPs, for example, the cell handover command includes the TA associated with the first TRP and the TA associated with the second TRP, in one implementation, the terminal device performs cell handover based on the first TRP; in another implementation, the terminal device performs cell handover based on the second TRP; in yet another implementation, the terminal device initiates access to both TRPs.

[0159] b) The terminal device has the acquired TA

[0160] The terminal device performs cell handover based on the acquired TA-associated TRP; or,

[0161] If the acquired TA is associated with two TRPs, for example, the terminal device autonomously acquires the TA associated with the first TRP and the TA associated with the second TRP, in one implementation, the terminal device performs cell handover based on the first TRP; in another implementation, the terminal device performs cell handover based on the second TRP (where an available TA exists); in yet another implementation, the terminal device initiates access to both TRPs; or...

[0162] If the acquired TA is associated with the second TRP, and the cell handover command indicates the TCI state associated with the first TRP, in one implementation, the terminal device performs cell handover based on the first TRP (which has an active TCI state); in another implementation, the terminal device performs cell handover based on the second TRP (which has an available TA).

[0163] c) The cell handover command includes CFRA resources (for RACH-based systems).

[0164] The terminal device performs cell handover based on the first TRP associated with the CFRA resource in the cell handover command; or...

[0165] The terminal device performs cell handover based on the second TRP; or,

[0166] The terminal device determines whether to perform cell handover based on the first TRP or the second TRP based on the PCI of the target cell. For example, if the PCI associated with the first TRP of the CFRA resource is different from the PCI of the target cell, but the PCI associated with the second TRP is the same as the PCI of the target cell, the terminal device performs cell handover based on the second TRP.

[0167] The terminal device performs a cell handover, which may include sending an RRC reconfiguration message to the network and / or triggering a random access procedure. For example, the terminal device handing over to a target TRP includes: the terminal device initiating access to the target TRP based on the RACH resources associated with the target TRP; and / or, the terminal device initiating access to the target TRP based on the beam (e.g., SSB and / or TCI state) associated with the target TRP; and / or, the terminal device initiating access to the target TRP based on the synchronization information (e.g., TCI state and / or TA) associated with the target TRP.

[0168] Optionally, when the target cell is associated with two TRPs, after initiating access based on one of the TRPs, the terminal device can also send information such as the TA and / or TCI status associated with the other TRP to the network. Additionally, optionally, if the target TRP is different from the TRP associated with an already acquired resource (e.g., TA, TCI status, and CFRA resource), the terminal device can subsequently initiate access to a non-target TRP associated with that resource based on that resource.

[0169] Example 2: The terminal device triggers the advance synchronization process, and the terminal device triggers the cell handover execution process.

[0170] The terminal device receives configuration information sent by the network device. This configuration information includes candidate cell configuration, which is used by the terminal device to perform cell handover subsequently. Furthermore, this configuration information also includes advance synchronization configuration, which is used by the terminal device to perform the advance synchronization process.

[0171] The terminal device performs an advance synchronization process based on the advance synchronization configuration. This advance synchronization process includes advance uplink synchronization and / or advance downlink synchronization. Advance uplink synchronization includes, for example, obtaining uplink TA, and advance downlink synchronization includes, for example, obtaining downlink timing and / or activating TCI status.

[0172] The early synchronization process is triggered by the terminal device. In one implementation, the terminal device can trigger it based on conditions, which can be configured by the network device. For example, these conditions could be L1 measurement-related conditions, L3 measurement-related conditions, conditions related to the measurement results of the serving cell (or serving beam), or conditions related to the measurement results of a candidate cell (or candidate beam). The terminal device can determine which candidate cell or candidate beam to initiate the early uplink synchronization process and / or early downlink synchronization process based on whether the measurement results of the serving beam and / or candidate beam meet the requirements. Alternatively, the terminal device can initiate the early uplink synchronization process and / or early downlink synchronization process based on the currently optimal candidate cell or candidate beam. In another implementation, the terminal device autonomously triggers TA measurements based on its internal implementation, where the autonomous triggering of TA measurements by the terminal device can be indicated, for example, by the network device.

[0173] The terminal device determines the second TRP in one or more of the following ways during the advance synchronization process:

[0174] a) Based on the network device configuration, for example, the network device indicates which TRP the advance synchronization process is initiated to;

[0175] b) Based on the priority or TRP defined by the standard, for example, determining to initiate early synchronization to the second TRP based on priority information, or by default initiating early synchronization only to the second TRP or at least to the second TRP;

[0176] c) Determined based on measurement results, for example, the second TRP is the TRP that the terminal device selects as the optimal candidate beam association based on the measurement results;

[0177] d) Determined based on the internal implementation of the terminal device;

[0178] e) The terminal device performs an advance synchronization process with two or all TRPs of the candidate cell.

[0179] After the terminal device determines the second TRP, it performs an advance synchronization process based on the resources associated with the second TRP, such as the TA and / or TCI status associated with the second TRP.

[0180] The cell handover process is triggered by the terminal device. The terminal device can determine the target cell based on conditions (e.g., L1 measurement conditions, L3 measurement conditions, CHO conditions) and perform cell handover.

[0181] The process of a terminal device performing cell handover may include, for example:

[0182] a) The terminal device has acquired the TA.

[0183] The terminal device performs cell handover based on the first TRP; or,

[0184] The terminal device performs cell handover based on the second TRP (there is an available TA); or,

[0185] The terminal device determines whether to perform cell handover based on the first TRP or the second TRP based on the PCI of the target cell. For example, if the PCI associated with the first TRP is the same as the PCI of the target cell, and the PCI associated with the second TRP is different from the PCI of the target cell, the terminal device performs cell handover based on the first TRP; or...

[0186] If the acquired TA is associated with two TRPs, for example, the terminal device autonomously acquires the TA associated with the first TRP and the TA associated with the second TRP, in one implementation, the terminal device performs cell handover based on the first TRP; in another implementation, the terminal device performs cell handover based on the second TRP; in yet another implementation, the terminal device initiates access to both TRPs; or...

[0187] If the acquired TA is associated with the second TRP, and the TCI state activated in the downlink synchronization is associated with the first TRP, in one implementation, the terminal device performs cell handover based on the first TRP (with an activated TCI state); in another implementation, the terminal device performs cell handover based on the second TRP (with an available TA).

[0188] b) The candidate cell configuration associated with the target cell includes CFRA resources (for RACH-based)

[0189] The terminal device performs cell handover based on a second TRP associated with the CFRA resources included in the candidate cell configuration; or,

[0190] The terminal device performs cell handover based on the first TRP; or,

[0191] The terminal device determines whether to perform cell handover based on the first TRP or the second TRP based on the PCI of the target cell. For example, if the PCI associated with the second TRP is different from the PCI of the target cell, and the PCI associated with the first TRP is the same as the PCI of the target cell, the terminal device performs cell handover based on the first TRP.

[0192] c) The terminal device has an activated TCI status.

[0193] The terminal device performs cell handover based on the TRP associated with the activated TCI state.

[0194] d) The terminal device determines whether to perform cell handover based on the first TRP or the second TRP based on the cell handover conditions.

[0195] For example, if the beam under the first TRP meets the cell handover conditions, but the beam under the second TRP does not meet the cell handover conditions, the terminal device performs cell handover based on the first TRP.

[0196] The terminal device performs a cell handover, which may include sending an RRC reconfiguration message to the network and / or triggering a random access procedure. For example, the terminal device handing over to a target TRP includes: the terminal device initiating access to the target TRP based on the RACH resources associated with the target TRP; and / or, the terminal device initiating access to the target TRP based on the beam (e.g., SSB and / or TCI state) associated with the target TRP; and / or, the terminal device initiating access to the target TRP based on the synchronization information (e.g., TCI state and / or TA) associated with the target TRP.

[0197] Optionally, when the target cell is associated with two TRPs, after the terminal device initiates access based on one of the TRPs, it can also send information such as the TA and / or TCI status associated with the other TRP to the network.

[0198] Example 3: The network device triggers the advance synchronization process, and the terminal device triggers the cell handover execution process.

[0199] The terminal device receives configuration information sent by the network device. This configuration information includes candidate cell configuration, which is used by the terminal device to perform cell handover subsequently. Furthermore, this configuration information also includes advance synchronization configuration, which is used by the terminal device to perform the advance synchronization process.

[0200] The terminal device performs an advance synchronization process based on the advance synchronization configuration. This advance synchronization process includes advance uplink synchronization and / or advance downlink synchronization. Advance uplink synchronization includes, for example, obtaining uplink TA, and advance downlink synchronization includes, for example, obtaining downlink timing and / or activating TCI status.

[0201] The early synchronization process is triggered by the terminal device. In one implementation, the terminal device can trigger it based on conditions, which can be configured by the network device. For example, these conditions could be L1 measurement-related conditions, L3 measurement-related conditions, conditions related to the measurement results of the serving cell (or serving beam), or conditions related to the measurement results of a candidate cell (or candidate beam). The terminal device can determine which candidate cell or candidate beam to initiate the early uplink synchronization process and / or early downlink synchronization process based on whether the measurement results of the serving beam and / or candidate beam meet the requirements. Alternatively, the terminal device can initiate the early uplink synchronization process and / or early downlink synchronization process based on the currently optimal candidate cell or candidate beam. In another implementation, the terminal device autonomously triggers TA measurements based on its internal implementation, where the autonomous triggering of TA measurements by the terminal device can be indicated, for example, by the network device.

[0202] The terminal device determines the second TRP in one or more of the following ways during the advance synchronization process:

[0203] a) Based on the network device configuration, for example, the network device indicates which TRP the advance synchronization process is initiated to;

[0204] b) Based on the priority or TRP defined by the standard, for example, determining to initiate early synchronization to the second TRP based on priority information, or by default initiating early synchronization only to the second TRP or at least to the second TRP;

[0205] c) Determined based on measurement results, for example, the second TRP is the TRP that the terminal device selects as the optimal candidate beam association based on the measurement results;

[0206] d) Determined based on the internal implementation of the terminal device;

[0207] e) The terminal device performs an advance synchronization process with two or all TRPs of the candidate cell.

[0208] After the terminal device determines the second TRP, it performs an advance synchronization process based on the resources associated with the second TRP, such as the TA and / or TCI status associated with the second TRP.

[0209] The cell handover process is triggered by the terminal device. The terminal device can determine the target cell based on conditions (e.g., L1 measurement conditions, L3 measurement conditions, CHO conditions) and perform cell handover.

[0210] The process of a terminal device performing cell handover may include, for example:

[0211] a) The terminal device has acquired the TA.

[0212] The terminal device performs cell handover based on the first TRP; or,

[0213] The terminal device performs cell handover based on the second TRP (there is an available TA); or,

[0214] The terminal device determines whether to perform cell handover based on the first TRP or the second TRP based on the PCI of the target cell. For example, if the PCI associated with the first TRP is the same as the PCI of the target cell, and the PCI associated with the second TRP is different from the PCI of the target cell, the terminal device performs cell handover based on the first TRP; or...

[0215] If the acquired TA is associated with two TRPs, for example, the terminal device autonomously acquires the TA associated with the first TRP and the TA associated with the second TRP, in one implementation, the terminal device performs cell handover based on the first TRP; in another implementation, the terminal device performs cell handover based on the second TRP; in yet another implementation, the terminal device initiates access to both TRPs; or...

[0216] If the acquired TA is associated with the second TRP, and the TCI state activated in the downlink synchronization is associated with the first TRP, in one implementation, the terminal device performs cell handover based on the first TRP (with an activated TCI state); in another implementation, the terminal device performs cell handover based on the second TRP (with an available TA).

[0217] b) The candidate cell configuration associated with the target cell includes CFRA resources (for RACH-based)

[0218] The terminal device performs cell handover based on a second TRP associated with the CFRA resources included in the candidate cell configuration; or,

[0219] The terminal device performs cell handover based on the first TRP; or,

[0220] The terminal device determines whether to perform cell handover based on the first TRP or the second TRP based on the PCI of the target cell. For example, if the PCI associated with the second TRP is different from the PCI of the target cell, and the PCI associated with the first TRP is the same as the PCI of the target cell, the terminal device performs cell handover based on the first TRP.

[0221] c) The terminal device has an activated TCI status.

[0222] The terminal device performs cell handover based on the TRP associated with the activated TCI state.

[0223] d) The terminal device determines whether to perform cell handover based on the first TRP or the second TRP based on the cell handover conditions. For example, if the beam under the first TRP meets the cell handover conditions, but the beam under the second TRP does not meet the cell handover conditions, the terminal device performs cell handover based on the first TRP.

[0224] The terminal device performs a cell handover, which may include sending an RRC reconfiguration message to the network and / or triggering a random access procedure. For example, the terminal device handing over to a target TRP includes: the terminal device initiating access to the target TRP based on the RACH resources associated with the target TRP; and / or, the terminal device initiating access to the target TRP based on the beam (e.g., SSB and / or TCI state) associated with the target TRP; and / or, the terminal device initiating access to the target TRP based on the synchronization information (e.g., TCI state and / or TA) associated with the target TRP.

[0225] Optionally, when the target cell is associated with two TRPs, after the terminal device initiates access based on one of the TRPs, it can also send information such as the TA and / or TCI status associated with the other TRP to the network.

[0226] The technical solution of this application addresses the problem of aligning TRPs between the advance synchronization process and the cell handover execution process. For example, for the LTM procedure triggered by the network device, additional indication is required; for CLTM, separate condition configuration is needed. If the TA and / or TCI states obtained during the LTM execution phase are inconsistent with the TA and / or TCI states obtained during the advance synchronization phase, the terminal device can, for example, trigger the RACH procedure by selecting the currently serving TRP (e.g., the first TRP), or select another TRP (e.g., the second TRP) to execute LTM. Furthermore, the terminal device can also send uplink messages to the unselected TRPs.

[0227] This application also provides corresponding technical solutions to address the problem of how to handle unselected TRPs. For example, when a TA is available, the terminal device can send an uplink message to the network device to indicate the availability of a TA, or rely on network scheduling to synchronize or access the unselected TRP; alternatively, it can trigger a RACH procedure; or, the RACH procedure triggered by the PDCCH command can be ignored.

[0228] In addition, the conditions for the completion of the LTM execution phase can be, for example, completion of access on both TRPs, completion of access only on the TRP currently being served, or completion of access on another TRP.

[0229] 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 and 8. 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.

[0230] Figure 7 is a schematic diagram of the structure of a terminal device provided in an embodiment of this application. The terminal device 700 shown in Figure 7 may include a transceiver unit 710. The transceiver unit 710 is used to hand over to a target cell based on a target TRP, wherein the target cell includes a first TRP and a second TRP, the second TRP is a TRP associated with an advance synchronization process, the first TRP is a TRP associated with a cell handover execution process, and the target TRP includes the first TRP and / or the second TRP.

[0231] In one implementation, the advance synchronization process is triggered by the terminal device, and the cell handover process is triggered by the network device; or, the advance synchronization process is triggered by the terminal device, and the cell handover process is triggered by the terminal device; or, the advance synchronization process is triggered by the network device, and the cell handover process is triggered by the terminal device; or, the advance synchronization process is triggered by the network device, and the cell handover process is triggered by the network device.

[0232] In one implementation, the advance synchronization process is triggered by the terminal device, including: the advance synchronization process is triggered by the terminal device based on predetermined conditions; or, the advance synchronization process is triggered by the terminal device based on its internal implementation.

[0233] In one implementation, the predetermined conditions are associated with one or more of the following: conditions related to Layer 1 measurements; conditions related to Layer 3 measurements; conditions related to the measurement results of the serving cell; and conditions related to the measurement results of the candidate cell.

[0234] In one implementation, the advance synchronization process is triggered by a network device, including: the advance synchronization process being triggered by the network device sending a PDCCH command; and / or, the advance synchronization process being triggered by the network device sending a MAC CE; and / or, the advance synchronization process being triggered by an indication message sent by the network device, the indication message being used to instruct the terminal device to perform advance synchronization based on its internal implementation.

[0235] In one implementation, the terminal device switches to the target cell based on the target TRP, which includes: the terminal device switches to the target cell based on the resources associated with the target TRP.

[0236] In one implementation, the resources associated with the target TRP include one or more of the following: Synchronization Signal Broadcast Channel Block (SSB), Transmission Configuration Indicator (TCI) status, Probe Reference Signal (SRS), Tracking Reference Signal (TRS), Channel State Information Reference Signal (CSI-RS), SSB Relative Identifier (SSBRI), Channel State Information Relative Identifier (CSIRI), Control Resource Set Pool, Physical Cell Identifier (PCI), Timing Advance Group Identifier (TAG ID), and Random Access Channel (RACH) resources.

[0237] In one implementation, the second TRP is indicated by the network device; or, the second TRP is determined based on priority information; or, the second TRP is determined based on the measurement results of the terminal device; or, the second TRP is a pre-agreed TRP that requires advance synchronization; or, the second TRP is a TRP determined by the terminal device based on its internal implementation.

[0238] In one implementation, the terminal device has an available TA, and the target TRP is the first TRP; or, the target TRP is the second TRP; or, the target TRP is the TRP associated with an available TA among the first TRP and the second TRP; or, the target TRP is the TRP with the same PCI as the target cell among the first TRP and the second TRP; or, the target TRP is the TRP with higher priority among the first TRP and the second TRP; or, the target TRP is the TRP associated with an activated TCI state among the first TRP and the second TRP; or, the target TRP is the TRP that meets the cell handover conditions among the first TRP and the second TRP; or, the target TRP includes both the first TRP and the second TRP.

[0239] In one implementation, the terminal device has available CFRA resources, and the target TRP is the first TRP; or, the target TRP is the second TRP; or, the target TRP is one of the first TRP and the second TRP associated with available CFRA resources; or, the target TRP is one of the first TRP and the second TRP that has the same PCI as the target cell; or, the target TRP is one of the first TRP and the second TRP associated with an activated TCI state; or, the target TRP is one of the first TRP and the second TRP that meets the cell handover conditions; or, the target TRP is the TRP with higher priority among the first TRP and the second TRP.

[0240] In one implementation, the terminal device has an activated TCI state, and the target TRP is the first TRP; or, the target TRP is the second TRP; or, the target TRP is the TRP associated with the activated TCI state among the first TRP and the second TRP; or, the target TRP is the TRP that meets the cell handover conditions among the first TRP and the second TRP; or, the target TRP is the TRP with higher priority among the first TRP and the second TRP.

[0241] In one implementation, the transceiver unit 710 is specifically configured to: send a Radio Resource Control (RRC) reconfiguration complete message to the target TRP; and / or, the terminal device switches to the target cell based on the RACH resources associated with the target TRP; and / or, the terminal device switches to the target cell based on the beam associated with the target TRP; and / or, the terminal device switches to the target cell based on the synchronization information associated with the target TRP.

[0242] In one implementation, the advance synchronization process includes an uplink synchronization process and / or a downlink synchronization process. The uplink synchronization process includes acquiring a TA (Translation Acquisition Target), and the downlink synchronization process includes acquiring downlink synchronization information and / or activating the TCI (Translation Controlled Interchange) state.

[0243] In one implementation, the target TRP is the first TRP, and the transceiver unit 710 is further configured to: send second information, the second information including an indication of the TA and / or TCI status associated with the second TRP, the second information being used for synchronization between the terminal device and the second TRP.

[0244] In one implementation, the cell handover of the terminal device includes one or more of the following: LTM, CHO, CLTM, CPA, CPC, and SCPAC.

[0245] It is understood that the transceiver unit 710 may be, for example, a transceiver 830. Additionally, the terminal device 700 may optionally include a processor 810 and a memory 820, as shown in Figure 8.

[0246] Figure 8 is a schematic structural diagram of a communication apparatus according to an embodiment of this application. The dashed lines in Figure 8 indicate that the unit or module is optional. The apparatus 800 can be used to implement the methods described in the above method embodiments. The apparatus 800 may be, for example, a chip, a terminal device, or a network device.

[0247] The apparatus 800 may include one or more processors 810. The processors 810 may support the apparatus 800 in implementing the methods described in the foregoing method embodiments. The processor 810 may be a general-purpose processor or a special-purpose processor. For example, the processor 810 may be a central processing unit (CPU). Alternatively, the processor 810 may also 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. A general-purpose processor may be a microprocessor or any conventional processor.

[0248] The apparatus 800 may further include one or more memories 820. The memories 820 store programs that can be executed by the processor 810, causing the processor 810 to perform the methods described in the above method embodiments. The memories 820 may be independent of the processor 810, or they may be integrated into the processor 810.

[0249] The device 800 may also include a transceiver 830. The processor 810 can communicate with other devices or chips via the transceiver 830. For example, the processor 810 can send and receive data with other devices or chips via the transceiver 830.

[0250] This application also provides a communication system. The communication system includes the terminal device and network device described above. In one implementation, the system further includes other devices that interact with the terminal device and network device.

[0251] This application also provides a computer-readable storage medium for storing a program. This computer-readable storage medium can be applied to a terminal device or network device provided in this application, and the program causes a computer to execute the methods performed by the terminal device or network device in various embodiments of this application.

[0252] This application also provides a computer program product. The computer program product includes a program. This computer program product can be applied to a terminal device or network device provided in this application embodiment, and the program causes a computer to execute the methods performed by the terminal device or network device in the various embodiments of this application.

[0253] This application also provides a computer program. This computer program can be applied to the terminal device or network device provided in this application, and the computer program causes the computer to execute the methods performed by the terminal device or network device in the various embodiments of this application.

[0254] It should be understood that the terms "system" and "network" in the embodiments of this application can be used interchangeably. Furthermore, the terminology used in this application is only for explaining specific embodiments of this application and is not intended to limit this 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.

[0255] 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.

[0256] In the embodiments of this application, "B corresponding to A" means that B is associated with A, and B can be determined based on A. However, it should also be understood that determining B based on A does not mean that B is determined solely based on A; B can also be determined based on A and / or other information.

[0257] 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.

[0258] 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.

[0259] 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.

[0260] 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.

[0261] 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.

[0262] 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.

[0263] 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 the embodiments of this application, depending on actual needs.

[0264] 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.

[0265] 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)).

[0266] 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 communication method, characterized in that, include: The terminal device switches to a target cell based on the target transmission and reception point (TRP). The target cell includes a first TRP and a second TRP. The second TRP is a TRP associated with the advance synchronization process, and the first TRP is a TRP associated with the cell handover execution process. The target TRP includes the first TRP and / or the second TRP.

2. The method according to claim 1, characterized in that, The advance synchronization process is triggered by the terminal device, and the cell handover process is triggered by the network device; or... The advance synchronization process is triggered by the terminal device, and the cell handover process is triggered by the terminal device. or, The advance synchronization process is triggered by the network device, and the cell handover process is triggered by the terminal device. or, The advance synchronization process is triggered by the network device, and the cell handover process is triggered by the network device.

3. The method according to claim 2, characterized in that, The advance synchronization process is triggered by the terminal device and includes: The advance synchronization process is triggered by the terminal device based on predetermined conditions; or... The advance synchronization process is triggered by the terminal device based on its internal implementation.

4. The method according to claim 3, characterized in that, The predetermined conditions are associated with one or more of the following: Conditions related to layer 1 measurement; Conditions related to layer 3 measurement; Conditions related to the measurement results of the service cell; Conditions related to the measurement results of the candidate cells.

5. The method according to any one of claims 2 to 4, characterized in that, The advance synchronization process is triggered by the network device and includes: The advance synchronization process is triggered by the network device sending a Physical Downlink Control (PDCCH) command; and / or, The advance synchronization process is triggered by a Media Access Control (MAC) control element (CE) sent by the network device; and / or, The advance synchronization process is triggered by an indication message sent by the network device, which instructs the terminal device to perform advance synchronization based on its internal implementation.

6. The method according to any one of claims 1 to 5, characterized in that, The terminal device switches to the target cell based on the target TRP, including: The terminal device switches to the target cell based on the resources associated with the target TRP.

7. The method according to claim 6, characterized in that, The resources associated with the target TRP include one or more of the following: Synchronization Signal Broadcast Channel Block (SSB), Transmission Configuration Indicator (TCI) status, Probe Reference Signal (SRS), Tracking Reference Signal (TRS), Channel State Information Reference Signal (CSI-RS), SSB Relative Identifier (SSBRI), Channel State Information Relative Identifier (CSIRI), Control Resource Set Pool, Physical Cell Identifier (PCI), Timing Advance Group Identifier (TAG ID), and Random Access Channel (RACH) resources.

8. The method according to any one of claims 1 to 7, characterized in that, The second TRP is indicated by the network device; or, The second TRP is determined based on priority information; or, The second TRP is determined based on the measurement results of the terminal device; or, The second TRP is a pre-agreed TRP that requires advance synchronization; or, The second TRP is the TRP determined by the terminal device based on its internal implementation.

9. The method according to any one of claims 1 to 8, characterized in that, The terminal device has a usable TA. The target TRP is the first TRP; or... The target TRP is the second TRP; or... The target TRP is the TRP associated with an available TA in the first TRP and the second TRP; or, The target TRP is the TRP that has the same PCI as the target cell among the first TRP and the second TRP; or, The target TRP is the TRP with higher priority between the first TRP and the second TRP; or... The target TRP is the TRP associated with the activated TCI state in the first TRP and the second TRP; or, The target TRP is the TRP that satisfies the cell handover conditions between the first TRP and the second TRP; or... The target TRP includes the first TRP and the second TRP.

10. The method according to any one of claims 1 to 9, characterized in that, The terminal device has available CFRA resources. The target TRP is the first TRP; or... The target TRP is the second TRP; or... The target TRP is the TRP associated with available CFRA resources in the first TRP and the second TRP; or, The target TRP is the TRP that has the same PCI as the target cell among the first TRP and the second TRP; or, The target TRP is the TRP associated with the activated TCI state in the first TRP and the second TRP; or, The target TRP is the TRP that satisfies the cell handover conditions between the first TRP and the second TRP; or... The target TRP is the TRP with higher priority between the first TRP and the second TRP.

11. The method according to any one of claims 1 to 10, characterized in that, The terminal device has an activated TCI state. The target TRP is the first TRP; or... The target TRP is the second TRP; or... The target TRP is the TRP associated with the activated TCI state in the first TRP and the second TRP; or, The target TRP is the TRP that satisfies the cell handover conditions between the first TRP and the second TRP; or... The target TRP is the TRP with higher priority between the first TRP and the second TRP.

12. The method according to any one of claims 1 to 11, characterized in that, The terminal device switches to the target cell based on the target TRP, including: The terminal device sends a Radio Resource Control (RRC) reconfiguration complete message to the target TRP; and / or The terminal device switches to the target cell based on the RACH resources associated with the target TRP; and / or, The terminal device switches to the target cell based on the beam associated with the target TRP; and / or, The terminal device switches to the target cell based on the synchronization information associated with the target TRP.

13. The method according to any one of claims 1 to 12, characterized in that, The advance synchronization process includes an uplink synchronization process and / or a downlink synchronization process. The uplink synchronization process includes obtaining the timing advance amount (TA), and the downlink synchronization process includes obtaining downlink synchronization information and / or activating the TCI state.

14. The method according to any one of claims 1 to 13, characterized in that, The target TRP is the first TRP, and the method further includes: The terminal device sends a second message, which includes an indication of the TA and / or TCI status associated with the second TRP. The second message is used for synchronization between the terminal device and the second TRP.

15. The method according to any one of claims 1 to 14, characterized in that, The cell handover of the terminal equipment includes one or more of the following: Low Protocol Layer Triggered Mobility TM, Conditional Handover Choreography (CHO), Conditional LTM, Conditional Primary / Secondary Cell Addition (CPA), Conditional Primary / Secondary Cell Change (CPC), and Subsequent Primary / Secondary Cell Addition / Change (SCPAC).

16. A terminal device, characterized in that, include: A transceiver unit is used to switch to a target cell based on a target transmission receiving point (TRP), wherein the target cell includes a first TRP and a second TRP, the second TRP is a TRP associated with an advance synchronization process, the first TRP is a TRP associated with a cell handover execution process, and the target TRP includes the first TRP and / or the second TRP.

17. The terminal device according to claim 16, characterized in that, The advance synchronization process is triggered by the terminal device, and the cell handover process is triggered by the network device; or... The advance synchronization process is triggered by the terminal device, and the cell handover process is triggered by the terminal device. or, The advance synchronization process is triggered by the network device, and the cell handover process is triggered by the terminal device. or, The advance synchronization process is triggered by the network device, and the cell handover process is triggered by the network device.

18. The terminal device according to claim 17, characterized in that, The advance synchronization process is triggered by the terminal device and includes: The advance synchronization process is triggered by the terminal device based on predetermined conditions; or... The advance synchronization process is triggered by the terminal device based on its internal implementation.

19. The terminal device according to claim 18, characterized in that, The predetermined conditions are associated with one or more of the following: Conditions related to layer 1 measurement; Conditions related to layer 3 measurement; Conditions related to the measurement results of the service cell; Conditions related to the measurement results of the candidate cells.

20. The terminal device according to any one of claims 17 to 19, characterized in that, The advance synchronization process is triggered by the network device and includes: The advance synchronization process is triggered by the network device sending a Physical Downlink Control (PDCCH) command; and / or, The advance synchronization process is triggered by a Media Access Control (MAC) control element (CE) sent by the network device; and / or, The advance synchronization process is triggered by an indication message sent by the network device, which instructs the terminal device to perform advance synchronization based on its internal implementation.

21. The terminal device according to any one of claims 16 to 20, characterized in that, The terminal device switches to the target cell based on the target TRP, including: The terminal device switches to the target cell based on the resources associated with the target TRP.

22. The terminal device according to claim 21, characterized in that, The resources associated with the target TRP include one or more of the following: Synchronization Signal Broadcast Channel Block (SSB), Transmission Configuration Indicator (TCI) status, Probe Reference Signal (SRS), Tracking Reference Signal (TRS), Channel State Information Reference Signal (CSI-RS), SSB Relative Identifier (SSBRI), Channel State Information Relative Identifier (CSIRI), Control Resource Set Pool, Physical Cell Identifier (PCI), Timing Advance Group Identifier (TAG ID), and Random Access Channel (RACH) resources.

23. The terminal device according to any one of claims 16 to 22, characterized in that, The second TRP is indicated by the network device; or, The second TRP is determined based on priority information; or, The second TRP is determined based on the measurement results of the terminal device; or, The second TRP is a pre-agreed TRP that requires advance synchronization; or, The second TRP is the TRP determined by the terminal device based on its internal implementation.

24. The terminal device according to any one of claims 16 to 23, characterized in that, The terminal device has a usable TA. The target TRP is the first TRP; or... The target TRP is the second TRP; or... The target TRP is the TRP associated with an available TA in the first TRP and the second TRP; or, The target TRP is the TRP that has the same PCI as the target cell among the first TRP and the second TRP; or, The target TRP is the TRP with higher priority between the first TRP and the second TRP; or... The target TRP is the TRP associated with the activated TCI state in the first TRP and the second TRP; or, The target TRP is the TRP that satisfies the cell handover conditions between the first TRP and the second TRP; or... The target TRP includes the first TRP and the second TRP.

25. The terminal device according to any one of claims 16 to 24, characterized in that, The terminal device has available CFRA resources. The target TRP is the first TRP; or... The target TRP is the second TRP; or... The target TRP is the TRP associated with available CFRA resources in the first TRP and the second TRP; or, The target TRP is the TRP that has the same PCI as the target cell among the first TRP and the second TRP; or, The target TRP is the TRP associated with the activated TCI state in the first TRP and the second TRP; or, The target TRP is the TRP that satisfies the cell handover conditions between the first TRP and the second TRP; or... The target TRP is the TRP with higher priority between the first TRP and the second TRP.

26. The terminal device according to any one of claims 16 to 25, characterized in that, The terminal device has an activated TCI state. The target TRP is the first TRP; or... The target TRP is the second TRP; or... The target TRP is the TRP associated with the activated TCI state in the first TRP and the second TRP; or, The target TRP is the TRP that satisfies the cell handover conditions between the first TRP and the second TRP; or... The target TRP is the TRP with higher priority between the first TRP and the second TRP.

27. The terminal device according to any one of claims 16 to 26, characterized in that, The transceiver unit is specifically used for: The terminal device sends a Radio Resource Control (RRC) reconfiguration complete message to the target TRP; and / or The terminal device switches to the target cell based on the RACH resources associated with the target TRP; and / or, The terminal device switches to the target cell based on the beam associated with the target TRP; and / or, The terminal device switches to the target cell based on the synchronization information associated with the target TRP.

28. The terminal device according to any one of claims 16 to 27, characterized in that, The advance synchronization process includes an uplink synchronization process and / or a downlink synchronization process. The uplink synchronization process includes obtaining the timing advance amount (TA), and the downlink synchronization process includes obtaining downlink synchronization information and / or activating the TCI state.

29. The terminal device according to any one of claims 16 to 28, characterized in that, The target TRP is the first TRP, and the transceiver unit is further configured to: Send a second message, the second message including an indication of the TA and / or TCI status associated with the second TRP, the second message being used for synchronization between the terminal device and the second TRP.

30. The terminal device according to any one of claims 16 to 29, characterized in that, The cell handover of the terminal equipment includes one or more of the following: Low Protocol Layer Triggered Mobility TM, Conditional Handover Choreography (CHO), Conditional LTM, Conditional Primary / Secondary Cell Addition (CPA), Conditional Primary / Secondary Cell Change (CPC), and Subsequent Primary / Secondary Cell Addition / Change (SCPAC).

31. A terminal 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 send signals so that the terminal device performs the method according to any one of claims 1 to 15.

32. An apparatus, characterized in that, Includes a processor for calling a program from memory to cause the apparatus to perform the method according to any one of claims 1 to 15.

33. 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 according to any one of claims 1 to 15.

34. A computer-readable storage medium, characterized in that, It contains a program that causes a computer to perform the method according to any one of claims 1 to 15.

35. A computer program product, characterized in that, Includes a program that causes a computer to perform the method according to any one of claims 1 to 15.

36. A computer program, characterized in that, The computer program causes the computer to perform the method according to any one of claims 1 to 15.

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