Method and apparatus for configuring and applying candidate cells

Abstract

Embodiments of the present application provide a method and device for configuring and applying candidate cells, the method comprising: receiving, by a terminal device, configuration information for configuring candidate cells sent by a network device; wherein one cell is not configured as a conditional handover (CHO) candidate cell and a layer 1 / layer 2 triggered mobility (LTM) candidate cell at the same time.

Description

Method and device for configuring and applying candidate cells Technical Field

[0001] The embodiments of the present application relate to the field of communication technologies. Background Art

[0002] Network-controlled mobility applies to connected devices and can be divided into two types of mobility: cell-level mobility and beam-level mobility. Cell-level mobility requires explicit Radio Resource Control (RRC) signaling, i.e., RRC-triggered handover.

[0003] The RRC-triggered handover mechanism requires the terminal device to at least reset the Media Access Control (MAC) entity and re-establish the Radio Link Control (RLC). RRC-managed handover with and without the Packet Data Convergence Protocol (PDCP) entity re-establishment is supported.

[0004] For Data Radio Bearers (DRBs) using RLC AM mode, PDCP can either re-establish with a security key update or initiate a data recovery procedure without a key update. For DRBs using RLC UM mode, PDCP can either re-establish with a security key update or remain unchanged without a key update. For Signalling Radio Bearers (SRBs), PDCP can remain unchanged without a key update, discard stored PDCP PDUs / SDUs, or re-establish with a security key update.

[0005] Changing the serving cell can be accomplished through Layer 1 (L1) / Layer 2 (L2) signaling. Figure 1 illustrates an example scenario for inter-cell mobility based on L1 / L2. As shown in Figure 1, when a terminal device moves from one cell's coverage area to another, a serving cell change is required at some point.

[0006] Currently, serving cell changes are triggered by Layer 3 (L3) measurements and completed by RRC signaling, with the addition of synchronization reconfiguration for PCell and PSCell changes, and the release of SCells when applicable. All cases involve a full L2 (and L1) reset, resulting in longer latency, greater overhead, and longer disruption than beam switching mobility.

[0007] The goal of L1 / L2 mobility enhancements is to ensure that serving cell changes through L1 / L2 signaling can reduce latency, overhead, and interruption time. To reduce mobility latency, L1 / L2-based inter-cell mobility mechanisms and processes may include: configuration and maintenance of multiple candidate cells to allow rapid application of candidate cell configurations; dynamic switching mechanisms between candidate serving cells (including special cells and secondary cells) based on L1 / L2 signaling for potentially applicable scenarios; L1 enhancements to inter-cell beam management, including L1 measurement and reporting, and beam indication; Timing Advance (TA) management; and CU-DU interface signaling to support L1 / L2 mobility.

[0008] It should be noted that the above introduction to the technical background is merely intended to provide a clear and complete description of the technical solutions of this application and facilitate understanding by those skilled in the art. Simply because these solutions are described in the background technology section of this application, it should not be assumed that the above technical solutions are well known to those skilled in the art.

[0009] Summary of the Invention

[0010] The inventors discovered that currently, network devices can configure CHO candidate cells or LTM candidate cells for terminal devices to support conditional handover (CHO) or L1 / L2 triggered mobility (LTM) operations. However, when a cell is configured as both a CHO candidate and an LTM candidate, the terminal device cannot determine whether to attempt CHO or LTM. As a result, the terminal device may not be able to apply fast failure recovery, resulting in longer outages.

[0011] To address at least one of the above problems, embodiments of the present application provide a method and apparatus for configuring and applying candidate cells.

[0012] According to one aspect of an embodiment of the present application, a method for configuring a candidate cell is provided, including:

[0013] The terminal device receives configuration information of the candidate cell sent by the network device;

[0014] Among them, a cell is not configured as a conditional handover (CHO) candidate cell and a layer 1 / layer 2 triggered mobility (LTM) candidate cell of the terminal device at the same time.

[0015] According to another aspect of an embodiment of the present application, there is provided an apparatus for configuring a candidate cell, including:

[0016] a receiving unit configured to receive configuration information of a candidate cell sent by a network device;

[0017] Among them, a cell is not configured as a conditional handover (CHO) candidate cell and a layer 1 / layer 2 triggered mobility (LTM) candidate cell of the terminal equipment at the same time.

[0018] According to another aspect of an embodiment of the present application, a method for applying a candidate cell is provided, including:

[0019] The terminal device receives configuration information of the candidate cell sent by the network device; and

[0020] The terminal device attempts to execute CHO or attempts to execute LTM according to regulations or based on the implementation of the terminal device or according to the configuration of the network device.

[0021] According to another aspect of an embodiment of the present application, a device for applying a candidate cell is provided, including:

[0022] a receiving unit configured to receive configuration information of a candidate cell sent by a network device; and

[0023] A processing unit that attempts to execute CHO or attempts to execute LTM according to regulations or based on the implementation of the terminal device or according to the configuration of the network device.

[0024] According to another aspect of an embodiment of the present application, a method for configuring a candidate cell is provided, including:

[0025] The network device sends configuration information of the candidate cell to the terminal device;

[0026] In which, a cell is not configured as a conditional handover (CHO) candidate cell and a layer 1 / layer 2 triggered mobility (LTM) candidate cell of the terminal device at the same time, or the terminal device attempts to perform CHO or attempts to perform LTM according to the configuration of the network device.

[0027] According to another aspect of an embodiment of the present application, there is provided an apparatus for configuring a candidate cell, including:

[0028] a sending unit, configured to send configuration information of a candidate cell to a terminal device;

[0029] In which, a cell is not configured as a conditional handover (CHO) candidate cell and a layer 1 / layer 2 triggered mobility (LTM) candidate cell of the terminal device at the same time, or the terminal device attempts to perform CHO or attempts to perform LTM according to the configuration of the network device.

[0030] One of the beneficial effects of the embodiments of the present application is that the terminal device can determine whether to attempt a CHO execution or an LTM execution, so that the terminal device can apply fast failure recovery when the handover fails, the wireless link fails, or the LTM fails, thereby reducing the interruption time.

[0031] With reference to the following description and accompanying drawings, specific embodiments of the present application are disclosed in detail, indicating the manner in which the principles of the present application can be employed. It should be understood that the embodiments of the present application are not limited in scope. Within the spirit and scope of the appended claims, the embodiments of the present application include many variations, modifications and equivalents.

[0032] Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0033] It should be emphasized that the term "include / comprising" when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The elements and features described in one figure or one embodiment of the present application can be combined with the elements and features shown in one or more other figures or embodiments. In addition, in the accompanying drawings, similar reference numerals represent corresponding parts in several figures and can be used to indicate corresponding parts used in more than one embodiment.

[0035] FIG1 is a diagram illustrating an example scenario of inter-cell mobility based on L1 / L2;

[0036] FIG2 is a schematic diagram of a communication system according to an embodiment of the present application;

[0037] FIG3 is a schematic diagram of the signaling process of LTM;

[0038] FIG4 is a schematic diagram of a failure recovery process;

[0039] FIG5 is a schematic diagram of a method for configuring candidate cells according to an embodiment of the present application;

[0040] FIG6 is a schematic diagram of a method for applying candidate cells according to an embodiment of the present application;

[0041] FIG7 is a schematic diagram of failure recovery according to an embodiment of the present application;

[0042] FIG8 is a schematic diagram of a method for configuring candidate cells according to an embodiment of the present application;

[0043] FIG9 is a schematic diagram of an apparatus for configuring or applying candidate cells according to an embodiment of the present application;

[0044] FIG10 is a schematic diagram of an apparatus for configuring candidate cells according to an embodiment of the present application;

[0045] FIG11 is a schematic diagram of a network device according to an embodiment of the present application;

[0046] FIG12 is a schematic diagram of a terminal device according to an embodiment of the present application. DETAILED DESCRIPTION

[0047] The above and other features of the present application will become apparent through the following description with reference to the accompanying drawings. In the description and the accompanying drawings, specific embodiments of the present application are disclosed in detail, which illustrate some embodiments in which the principles of the present application can be adopted. It should be understood that the present application is not limited to the described embodiments. On the contrary, the present application includes all modifications, variations and equivalents that fall within the scope of the appended claims.

[0048] In the embodiments of the present application, the terms "first", "second", etc. are used to distinguish different elements from the name, but do not indicate the spatial arrangement or temporal order of these elements, and these elements should not be limited by these terms. The term "and / or" includes any one and all combinations of one or more of the associated listed terms. The terms "comprising", "including", "having", etc. refer to the presence of the stated features, elements, components or components, but do not exclude the presence or addition of one or more other features, elements, components or components.

[0049] In the embodiments of this application, the singular forms "a," "the," etc. include plural forms and should be broadly understood to mean "a" or "a type" rather than being limited to "one." Furthermore, the term "said" should be understood to include both singular and plural forms, unless the context clearly indicates otherwise. Furthermore, the term "according to" should be understood to mean "at least in part based on...", and the term "based on" should be understood to mean "at least in part based on...", unless the context clearly indicates otherwise.

[0050] In the embodiments of the present application, the term "communication network" or "wireless communication network" may refer to a network that complies with any of the following communication standards, such as Long Term Evolution (LTE), enhanced Long Term Evolution (LTE-A, LTE-Advanced), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), etc.

[0051] Furthermore, communication between devices in the communication system may be carried out according to communication protocols of any stage, for example, including but not limited to the following communication protocols: 1G (generation), 2G, 2.5G, 2.75G, 3G, 4G, 4.5G and 5G, New Radio (NR), future 6G, etc., and / or other communication protocols currently known or to be developed in the future.

[0052] In the embodiments of the present application, the term "network device" refers to, for example, a device in a communication system that connects a terminal device to the communication network and provides services to the terminal device. Network devices may include, but are not limited to, the following devices: base station (BS), access point (AP), transmission reception point (TRP), broadcast transmitter, mobile management entity (MME), gateway, server, radio network controller (RNC), base station controller (BSC), etc.

[0053] Among them, base stations may include but are not limited to: NodeB (NodeB or NB), evolved NodeB (eNodeB or eNB) and 5G base station (gNB), IAB host, etc., and may also include remote radio head (RRH, Remote Radio Head), remote radio unit (RRU, Remote Radio Unit), relay (relay) or low-power node (such as femeto, pico, etc.). The term "base station" can include some or all of their functions. Each base station can provide communication coverage for a specific geographical area. The term "cell" can refer to a base station and / or its coverage area, depending on the context in which the term is used.

[0054] In the embodiments of the present application, the term "user equipment" (UE) or "terminal equipment" (TE) refers to, for example, a device that accesses a communication network through a network device and receives network services. A terminal device can be fixed or mobile and may also be referred to as a mobile station (MS), a terminal, a subscriber station (SS), an access terminal (AT), a station, and so on.

[0055] Among them, terminal devices may include but are not limited to the following devices: cellular phones, personal digital assistants (PDAs), wireless modems, wireless communication devices, handheld devices, machine-type communication devices, laptop computers, cordless phones, smart phones, smart watches, digital cameras, etc.

[0056] For another example, in scenarios such as the Internet of Things (IoT), the terminal device can also be a machine or device for monitoring or measurement, including but not limited to: machine type communication (MTC) terminal, vehicle-mounted communication terminal, device-to-device (D2D) terminal, machine-to-machine (M2M) terminal, and so on.

[0057] In addition, the term "network side" or "network device side" refers to one side of the network, which can be a base station or one or more network devices as described above. The term "user side" or "terminal side" or "terminal device side" refers to the user or terminal side, which can be a UE or one or more terminal devices as described above. Unless otherwise specified herein, "device" can refer to either network equipment or terminal equipment.

[0058] The following describes the scenarios of the embodiments of the present application through examples, but the present application is not limited thereto.

[0059] FIG2 is a schematic diagram of a communication system according to an embodiment of the present application, schematically illustrating a situation using a terminal device and a network device as an example. As shown in FIG2 , a communication system 100 may include a network device 101 and terminal devices 102 and 103. For simplicity, FIG2 illustrates only two terminal devices and one network device as an example, but the embodiments of the present application are not limited thereto.

[0060] In the embodiment of the present application, existing services or future services can be transmitted between the network device 101 and the terminal devices 102 and 103. For example, these services may include but are not limited to: enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable and low-latency communication (URLLC), etc.

[0061] It is worth noting that FIG2 shows that both terminal devices 102 and 103 are within the coverage range of network device 101, but the present application is not limited thereto. Both terminal devices 102 and 103 may not be within the coverage range of network device 101, or one terminal device 102 may be within the coverage range of network device 101 while the other terminal device 103 is outside the coverage range of network device 101.

[0062] The terminal device can perform conditional handover (CHO), where the network device (e.g., the source gNB) can perform CHO configuration for the terminal device via RRC, such as configuring CHO candidate cells. For more information about the CHO process, please refer to the relevant technology.

[0063] The terminal device may also perform an LTM process, in which a network device (e.g., a gNB) receives an L1 measurement report from the terminal device, and based on the L1 measurement report, the network device may change the serving cell of the terminal device via a cell switch command issued by a MAC CE.

[0064] For example, after an LTM cell handover, the terminal device does not update its security keys; subsequent LTM is supported. LTM supports intra-gNB-DU mobility and inter-gNB-DU mobility within a gNB-CU. LTM supports both intra-frequency and inter-frequency mobility, including mobility to an inter-frequency cell other than the current serving cell. LTM can support the following scenarios: PCell changes in non-CA and non-DC scenarios; PCell changes in CA scenarios; dual connectivity scenarios, MCG PCell changes, and SCG PSCell changes not involving the mobile node (i.e., intra-SN PSCell changes).

[0065] Figure 3 is a schematic diagram of the LTM signaling process. As shown in Figure 3, the LTM process may include:

[0066] Step 1: The UE sends a MeasurementReport message to the gNB. The gNB decides to configure LTM and initiates candidate cell configuration.

[0067] Step 2: The gNB sends an RRCReconfiguration message to the UE, including the LTM candidate cell configuration of one or more candidate cells.

[0068] Step 3: The UE stores the LTM candidate cell configuration and sends an RRCReconfigurationComplete message to the gNB.

[0069] Step 4: Before receiving the cell change command, the UE performs DL synchronization of the candidate cell;

[0070] When UE-based TA measurement is configured, the UE obtains the TA value of the candidate cell through measurement. Otherwise, before receiving a cell change command, if the network requests that the UE perform early TA acquisition of the candidate cell, this can be accomplished by triggering a CFRA from the PDCCH order of the source cell and then sending a preamble to the indicated candidate cell. To minimize data interruption in the source cell caused by the CFRA to the candidate cell, the UE does not receive a random access response from the network to obtain the TA value. The TA value of the candidate cell is indicated in the cell handover command. The UE does not maintain a TA timer for the candidate cell and relies on the network to ensure TA validity.

[0071] Step 5: The UE performs L1 measurements on the configured candidate cells and sends an L1 measurement report to the gNB. L1 measurements should be performed whenever RRC reconfiguration (step 2) applies.

[0072] Step 6: The gNB decides to perform a cell change to the target cell and sends a MAC CE indicating a cell change with the candidate configuration index of the target cell. The UE switches to the target cell and applies the configuration indicated by the candidate configuration index.

[0073] Step 7: If the UE does not have a valid TA for the target cell, the UE performs a random access procedure to the target cell. If the LTM cell change command MAC CE includes CFRA information, the UE performs CFRA;

[0074] Step 8: The UE completes the LTM cell change procedure by sending an RRCReconfigurationComplete message to the target cell. If the UE has performed a random access procedure in step 7, the UE considers that the LTM cell change has been successfully completed when the random access procedure is successfully completed; for RACH-less LTM, the UE considers that the LTM cell change has been successfully completed when the UE determines that the network has successfully received its first UL data. The UE determines the successful reception of its first UL data by receiving a newly transmitted PDCCH addressed by the UE's C-RNTI in the target cell and after scheduling the first UL data. The PDCCH carries a DL assignment or a UL grant of the same HARQ process as the first UL data.

[0075] The candidate LTM is determined by repeating the steps of early synchronization, LTM cell change execution, and LTM cell change completion. After each LTM cell change is completed, the other LTM candidate cell configurations are not released. That is, using the LTM candidate cell configuration provided in step 2, steps 4-8 can be performed multiple times.

[0076] The above schematically illustrates CHO and LTM. The following further illustrates recovery from handover failure and recovery from radio link failure.

[0077] For handover failure recovery, NR supports a timer-based Handover Failure (HOF) procedure. The RRC connection reestablishment procedure is used for handover failure recovery, except in certain CHO or DAPS handover scenarios:

[0078] -When DAPS handover fails, if the source link has not been released, the UE falls back to the source cell configuration, restores the connection with the source cell, and reports the DAPS handover failure through the source, without triggering RRC connection re-establishment;

[0079] - When the initial CHO execution attempt fails or the HO handover fails, the UE performs cell selection and if the selected cell is a CHO candidate and if the network has configured the UE to attempt CHO after handover / CHO failure, then the UE attempts CHO execution once, otherwise it performs re-establishment.

[0080] For radio link failure recovery, after RLF is declared, the UE:

[0081] - Maintain RRC_CONNECTED;

[0082] - In the case of a DAPS handover, for RLF in the source cell: all data transmission or reception over the source link is stopped and the source link is released, but the source RRC configuration is maintained; if a handover failure is subsequently detected in the target cell, the UE: selects a suitable cell and initiates RRC re-establishment; if no suitable cell is found within a certain period of time after declaring handover failure, it enters RRC_IDLE;

[0083] - In case of CHO, for RLF in the source cell: select a suitable cell and if the selected cell is a CHO candidate and if the network has configured CHO after RLF, the UE attempts CHO once, otherwise performs re-establishment; if no suitable cell is found within a certain time after declaring handover failure, enter RRC_IDLE;

[0084] - In case of LTM (L1 / L2 Triggered Mobility), for RLF in the source cell: select a suitable cell and if the selected cell is an LTM candidate and if the network has configured LTM after RLF, the UE attempts LTM once, otherwise performs re-establishment; if no suitable cell is found within a certain period of time after declaring handover failure, enter RRC_IDLE;

[0085] - Otherwise, for RLF in the serving cell or in the target cell before releasing the source cell in case of DAPS handover: select a suitable cell and initiate RRC re-establishment; if no suitable cell is found within a certain period of time after declaring RLF, enter RRC_IDLE.

[0086] Figure 4 illustrates a failure recovery process. As shown in Figure 4, when a radio link failure or handover failure occurs, the terminal device initiates the RRC connection reestablishment process, which involves first selecting a cell. If the selected cell is a CHO candidate, the terminal device attempts a CHO. Otherwise, the RRC connection reestablishment process continues, sending an RRC reestablishment request message.

[0087] In addition, when a wireless link failure or an LTM cell change failure occurs, the terminal device initiates the RRC connection reconstruction process, that is, it first selects a cell; if the selected cell is an LTM candidate cell, the terminal device attempts LTM execution once; otherwise, it continues the RRC connection reconstruction process, that is, it sends an RRC reconstruction request message.

[0088] According to the above mechanism, when a radio link failure occurs, if the selected cell is an LTM candidate or a CHO candidate, the UE attempts either LTM or CHO. However, if a cell is configured as both a CHO candidate and an LTM candidate, the UE cannot determine whether to attempt CHO or LTM. Consequently, the UE may be unable to apply fast failure recovery, resulting in longer outages.

[0089] Embodiments of the first aspect

[0090] The embodiment of the present application provides a method for configuring candidate cells. FIG5 is a schematic diagram of the method for configuring candidate cells according to the embodiment of the present application. As shown in FIG5 , the method includes:

[0091] 501. The terminal device receives configuration information of a candidate cell sent by a network device; wherein a cell is not configured as a conditional handover (CHO) candidate cell and a layer 1 / layer 2 triggered mobility (LTM) candidate cell of the terminal device at the same time.

[0092] It is worth noting that FIG5 above is merely a schematic illustration of an embodiment of the present application, and the present application is not limited thereto. For example, the execution order of the various operations may be appropriately adjusted, and other operations may be added or some operations may be reduced. Those skilled in the art may make appropriate modifications based on the above description, and are not limited to the description of FIG5 above.

[0093] In some embodiments, the terminal device does not support CHO and LTM simultaneously.

[0094] For example, if the terminal device (MCG) is configured with CHO or conditional reconfiguration (ConditionalReconfig) of the MCG, it is not configured with LTM, LTM-Config, or LTM-Candidate.

[0095] For another example, if the terminal device (MCG) is configured with LTM, LTM-Config, or LTM-Candidate, it is not configured with CHO or Conditional Reconfiguration of MCG.

[0096] In some embodiments, the terminal device supports CHO and LTM simultaneously; the first cell of the terminal device is a CHO candidate cell, the second cell is an LTM candidate cell, and the first cell and the second cell are different cells.

[0097] In some embodiments, the first cell is not configured as an LTM candidate cell by the network device, and the second cell is not configured as a CHO candidate cell by the network device. For example, the network device is a gNB, or a gNB-CU of a serving cell, or a gNB-CU of a source cell, or a gNB-DU of a candidate cell.

[0098] For example, the CU ensures that the first cell is not configured as an LTM candidate cell and the second cell is not configured as a CHO candidate cell.

[0099] In some embodiments, the first cell is also configured by the network device as an LTM candidate cell, or the second cell is also configured by the network device as a CHO candidate cell, then the terminal device releases the LTM configuration or CHO configuration when switching is performed or when a radio link failure is triggered or when switching fails or when an RRC connection reconstruction process is initiated.

[0100] For example, the terminal device releases the LTM configuration when at least one of the following events occurs: handover (L3HO / CHO / LTM) execution (e.g., T304 start / run), radio link failure triggering and / or handover failure (e.g., T304 timeout), RRC connection reestablishment process initiation (e.g., T311 start / run).

[0101] For another example, the terminal device releases the CHO configuration when at least one of the following events occurs: handover (L3HO / CHO / LTM) execution, radio link failure triggering and / or handover failure (T304 timeout), RRC connection reestablishment process initiation.

[0102] In some embodiments, the handover failure includes a timer T304 or a first timer expiring, the first timer being different from the timer T304. For example, the timer T304 is started when the LTM cell change is executed; or the first timer is started when the LTM cell change is executed.

[0103] In some embodiments, the timer T304 or the first timer is configured with a first value, which is applicable to LTM based on random access and LTM based on non-random access; or, the timer T304 or the first timer is configured with a second value and a third value, the second value is applicable to LTM based on random access, and the third value is applicable to LTM based on non-random access.

[0104] In some embodiments, the terminal device initiates RRC connection reconstruction after the wireless link fails; wherein, if the cell selected in the cell selection is a CHO candidate cell, the terminal device attempts to perform CHO; if the cell selected in the cell selection is an LTM candidate cell, the terminal device attempts to perform LTM.

[0105] The radio link failure includes: RLF of the source cell when CHO is configured, or RLF when LTM is configured, or RLF of the source cell when LTM is configured, or RLF of the target cell when LTM is configured.

[0106] For example, if RRC connection reestablishment is initiated due to radio link failure, if the cell selected in cell selection is a CHO candidate cell, the UE attempts CHO execution once; if the cell selected in cell selection is an LTM candidate cell, the UE attempts LTM execution once.

[0107] The CHO candidate cell may be a CHO candidate cell of an MCG or a CHO candidate cell of an SCG; or, the CHO candidate cell of an MCG may be a CHO candidate cell of an MCG not configured with an SCG, or may be a CHO candidate cell of an MCG configured with an SCG.

[0108] In some embodiments, the terminal device initiates RRC connection reconstruction after LTM fails; wherein, if the cell selected in the cell selection is a CHO candidate cell, the terminal device attempts to perform CHO; if the cell selected in the cell selection is an LTM candidate cell, the terminal device attempts to perform LTM.

[0109] For example, if RRC connection reestablishment is initiated due to LTM failure, if the cell selected in the cell selection is a CHO candidate cell, the UE attempts CHO execution once; (otherwise,) if the cell selected in the cell selection is an LTM candidate cell, the UE attempts LTM execution once; otherwise, the terminal device sends an RRC reestablishment request.

[0110] In some embodiments, the terminal device initiates RRC connection reestablishment after LTM fails; wherein, if the cell selected in the cell selection is an LTM candidate cell, the terminal device attempts to perform LTM; otherwise, the terminal device sends an RRC reestablishment request.

[0111] For example, if RRC connection reestablishment is initiated due to LTM failure, if the cell selected in cell selection is an LTM candidate cell, the UE attempts LTM execution once; otherwise (for example, the cell selected in cell selection is a CHO candidate cell), the UE sends an RRC reestablishment request.

[0112] In some embodiments, the terminal device initiates RRC connection reconstruction after a handover failure, wherein, if the cell selected in the cell selection is a CHO candidate cell, the terminal device attempts to perform CHO; if the cell selected in the cell selection is an LTM candidate cell, the terminal device attempts to perform LTM.

[0113] The switching may include at least one of the following: reconfiguration with synchronization; L3 synchronization reconfiguration; network-triggered L3 synchronization reconfiguration of MCG; conditional synchronization reconfiguration of MCG; conditional synchronization reconfiguration of MCG including conditional synchronization reconfiguration of SCG; L1 / L2 triggered mobility (LTM) of MCG.

[0114] For example, if the RRC connection reconstruction is initiated due to the failure of synchronous reconfiguration (reconfiguration with sync), if the cell selected in the cell selection is a CHO candidate cell, the UE attempts a CHO execution; (otherwise,) if the cell selected in the cell selection is an LTM candidate cell, the UE attempts a LTM execution; otherwise, the terminal device sends an RRC reconstruction request.

[0115] In some embodiments, the terminal device initiates RRC connection reestablishment after a handover failure, wherein, if the cell selected in the cell selection is a CHO candidate cell, the terminal device attempts to perform CHO; otherwise, the terminal device sends an RRC reestablishment request.

[0116] For example, if the RRC connection reestablishment is initiated due to a failure of synchronous reconfiguration (reconfiguration with sync), if the cell selected in the cell selection is a CHO candidate cell, the UE attempts a CHO execution; otherwise (the cell selected in the cell selection is an LTM candidate cell), the UE sends an RRC reestablishment request.

[0117] The above is a schematic description of the embodiments of the present application, but the present application is not limited thereto and will be further described below with examples.

[0118] Table 1-1 and Table 1-2 illustrate an example, but the present application is not limited thereto.

[0119] Table 1-1

[0120] or,

[0121] Table 1-2

[0122] In the above example, “cannot” can be replaced by shall not / will not etc.

[0123] As shown in Table 1, if the UE is not configured with LTM / CHO at the same time, a cell is not configured as a CHO candidate cell and an LTM candidate cell of the UE at the same time.

[0124] Table 2 illustrates another example, but the present application is not limited thereto.

[0125] Table 2

[0126] Table 3 illustrates another example, but the present application is not limited thereto.

[0127] Table 3

[0128] The above embodiments are merely exemplary of the present invention, but the present invention is not limited thereto. Appropriate modifications may be made based on the above embodiments. For example, the above embodiments may be used individually, or one or more of the above embodiments may be combined.

[0129] It can be seen from the above embodiments that, through the embodiments of the present application, a cell is not configured as a CHO candidate cell and an LTM candidate cell at the same time, so that the cell selected in the rapid recovery cell selection cannot be both a CHO candidate cell and an LTM candidate cell. The terminal device can perform rapid failure recovery, thereby reducing service interruption time and improving user experience.

[0130] Embodiments of the second aspect

[0131] The embodiment of the present application provides a method for applying candidate cells. FIG6 is a schematic diagram of the method for applying candidate cells according to the embodiment of the present application. As shown in FIG6 , the method includes:

[0132] 601, the terminal device receives configuration information of candidate cells sent by the network device; and

[0133] 602 : The terminal device attempts to execute CHO or attempts to execute LTM according to regulations, based on implementation of the terminal device, or according to configuration of the network device.

[0134] It is worth noting that FIG6 above is merely a schematic illustration of an embodiment of the present application, and the present application is not limited thereto. For example, the execution order of the various operations may be appropriately adjusted, and other operations may be added or some operations may be reduced. Those skilled in the art may make appropriate modifications based on the above description, and are not limited to the description of FIG6 above.

[0135] In some embodiments, the terminal device initiates RRC connection reconstruction after a wireless link failure or a handover failure; the terminal device performs cell selection; according to the selected cell, the terminal device attempts to execute CHO or attempts to execute LTM in accordance with regulations or based on the implementation of the terminal device or in accordance with the configuration of the network device.

[0136] In some embodiments, the radio link failure includes: RLF of the source cell when CHO is configured, or RLF when LTM is configured, or RLF of the source cell when LTM is configured, or RLF of the target cell when LTM is configured.

[0137] In some embodiments, the switching includes at least one of the following: synchronous reconfiguration; L3 synchronous reconfiguration; network-triggered L3 synchronous reconfiguration of MCG; conditional synchronous reconfiguration of MCG; conditional synchronous reconfiguration of MCG including conditional synchronous reconfiguration of SCG; L1 / L2 triggered mobility (LTM) of MCG.

[0138] In some embodiments, the terminal device attempts to perform CHO or attempts to perform LTM as specified.

[0139] For example, if the cell selected in the cell selection is an LTM candidate cell, the terminal device attempts to perform LTM; otherwise, if the cell selected in the cell selection is a CHO candidate cell, the terminal device attempts to perform CHO; otherwise, the terminal device sends an RRC reestablishment request.

[0140] Figure 7 is a schematic diagram of failure recovery in an embodiment of the present application. As shown in Figure 7, when a radio link failure or handover failure occurs, the terminal device initiates the RRC connection reestablishment process, i.e., first performs cell selection; if the selected cell is an LTM candidate cell, the terminal device attempts an LTM execution; otherwise, if the selected cell is a CHO candidate cell, the terminal device attempts a CHO execution; otherwise, the terminal device continues the RRC connection reestablishment process, i.e., sends an RRC reestablishment request message.

[0141] Table 4 illustrates another example, but the present application is not limited thereto.

[0142] Table 4

[0143] Table 5 illustrates another example, but the present application is not limited thereto.

[0144] Table 5

[0145] Table 6 illustrates another example, but the present application is not limited thereto.

[0146] Table 6

[0147] Therefore, when a cell is both an LTM candidate and a CHO candidate, LTM execution is prioritized. This allows terminal devices to quickly recover from failures, reducing service interruption and improving user experience. Furthermore, while removing restrictions on network configuration allows for greater network flexibility, terminal behavior is defined, reducing the amount of terminal device testing and, consequently, lowering terminal device costs.

[0148] In some embodiments, LTM is attempted or CHO is attempted based on the implementation of the terminal device.

[0149] For example, if the cell selected in the cell selection is an LTM candidate cell, the terminal device attempts to perform LTM; otherwise, the terminal device sends an RRC re-establishment request. Alternatively, if the cell selected in the cell selection is a CHO candidate cell, the terminal device attempts to perform CHO; otherwise, the terminal device sends an RRC re-establishment request. Alternatively, if the cell selected in the cell selection is both a CHO candidate cell and an LTM candidate cell, the terminal device attempts to perform CHO or attempts to perform LTM.

[0150] For another example, LTM execution does not include RLC reconstruction and / or PDCP data recovery, then the terminal device attempts to execute LTM; and / or, LTM configuration includes non-contention random access (CFRA) configuration, then the terminal device attempts to execute LTM.

[0151] For another example, if LTM execution includes RLC reestablishment and / or PDCP data recovery, the terminal device attempts to perform CHO; and / or if LTM configuration does not include non-contention random access (CFRA) configuration, the terminal device attempts to perform CHO.

[0152] In some embodiments, CHO is attempted or LTM is attempted depending on the configuration of the network device.

[0153] For example, the terminal device attempts to perform CHO according to the configuration of the network device in the following cases: CHO is prioritized by the network device configuration; and / or the network device configures attemptCondReconfig but does not configure attemptLTM-Switch; and / or the LTM configuration is released by the network device.

[0154] For another example, the terminal device attempts to execute LTM according to the configuration of the network device in the following cases: LTM is configured with priority by the network device; and / or the network device is configured with attemptLTM-Switch but not attemptCondReconfig; and / or the CHO configuration is released by the network device.

[0155] Table 7 illustrates another example, but the present application is not limited thereto.

[0156] Table 7

[0157] As shown in Table 7, the network can configure CHO first, and the terminal device attempts CHO execution based on the network configuration.

[0158] Table 8 illustrates another example, but the present application is not limited thereto.

[0159] Table 8

[0160] As shown in Table 8, the network can be configured with LTM first, and the terminal device attempts LTM execution based on the network configuration.

[0161] Table 9 illustrates another example, but the present application is not limited thereto.

[0162] Table 9

[0163] As shown in Table 9, the network can prioritize CHO after configuration failure, and the terminal device attempts CHO execution based on the network configuration.

[0164] Table 10 illustrates another example, but the present application is not limited thereto.

[0165] Table 10

[0166] As shown in Table 10, the network can prioritize LTM after configuration failure, and the terminal device attempts LTM execution based on the network configuration.

[0167] Table 11 shows another example, but the present application is not limited thereto. For example, "upon CHO execution is performed" can be replaced by triggering RLF, T304 timeout, RRC re-establishment initiation, etc.

[0168] Table 11

[0169] As shown in Table 11, the network can be configured to release the LTM configuration, and the terminal device attempts CHO execution based on the network configuration.

[0170] Table 12 shows another example, but the present application is not limited thereto. For example, "upon CHO execution is performed" can be replaced by triggering RLF, T304 timeout, RRC re-establishment initiation, etc.

[0171] Table 12

[0172] As shown in Table 12, the network can be configured to release the CHO configuration, and the terminal device attempts LTM execution based on the network configuration.

[0173] Therefore, when a cell is both an LTM candidate and a CHO candidate, LTM or CHO execution is attempted based on the network device configuration, allowing the terminal device to quickly recover from failures, thereby reducing service interruption and improving user experience. Furthermore, terminal behavior is deterministic and controlled by the network, reducing the amount of terminal device testing compared to terminal-based solutions, thereby reducing terminal device costs.

[0174] The above embodiments are merely exemplary of the present invention, but the present invention is not limited thereto. Appropriate modifications may be made based on the above embodiments. For example, the above embodiments may be used alone, or one or more of the above embodiments may be combined.

[0175] It can be seen from the above embodiments that through the embodiments of the present application, by attempting to execute CHO or attempting to execute LTM in accordance with regulations or based on the implementation of the terminal device or according to the configuration of the network device, the terminal device can perform rapid failure recovery, thereby reducing business interruption time and improving user experience.

[0176] Embodiments of the third aspect

[0177] The embodiment of the present application provides a method for configuring candidate cells, which is described from the perspective of a network device. The embodiment of the third aspect can be combined with the embodiments of the first and second aspects, and the same contents as the embodiments of the first and second aspects will not be repeated.

[0178] FIG8 is a schematic diagram of a method for configuring candidate cells according to an embodiment of the present application. As shown in FIG8 , the method includes:

[0179] 801, the network device sends configuration information of candidate cells to the terminal device;

[0180] In which, a cell is not configured as a conditional handover (CHO) candidate cell and a layer 1 / layer 2 triggered mobility (LTM) candidate cell of the terminal device at the same time, or the terminal device attempts to perform CHO or attempts to perform LTM according to the configuration of the network device.

[0181] It is worth noting that FIG8 above is merely a schematic illustration of an embodiment of the present application, and the present application is not limited thereto. For example, the execution order of the various operations may be appropriately adjusted, and other operations may be added or some operations may be reduced. Those skilled in the art may make appropriate modifications based on the above description, and are not limited to the description of FIG8 above.

[0182] In some embodiments, the terminal device does not support CHO and LTM simultaneously.

[0183] The network device receives a measurement report message from the terminal device and decides to initiate LTM configuration.

[0184] Alternatively, the network device receives a measurement report message from a terminal device, and if the terminal device is configured with conditional reconfiguration, the network device decides not to initiate LTM configuration. Alternatively, the network device releases conditional reconfiguration and decides to initiate LTM configuration.

[0185] When the network device decides to initiate LTM configuration, the network device sends the LTM configuration to the terminal device.

[0186] For example, the network device is a gNB.

[0187] For example, in a CU-DU split scenario, the gNB-CU decides to initiate LTM configuration. The gNB-CU sends a UE CONTEXT MODIFICATION REQUEST message including the target candidate cell ID to the gNB-DU (the serving / source / serving cell of the UE). If the gNB-DU accepts the LTM configuration request, it responds with a UE CONTEXT MODIFICATION RESPONSE message including the generated low-layer RRC configuration of the accepted target candidate cell. The gNB-CU sends a DL RRC MESSAGE TRANSFER message to the gNB-DU, including the generated RRCReconfiguration message carrying the LTM configuration. The gNB-DU forwards the received RRCReconfiguration message to the UE.

[0188] Alternatively, the gNB-CU sends a UE CONTEXT SETUP REQUEST message including the ID of the target candidate cell to the (candidate) gNB-DU. If the (candidate) gNB-DU accepts the LTM configuration request, the (candidate) gNB-DU responds with a UE CONTEXT SETUP RESPONSE message including the generated low-layer RRC configuration and RS configuration of the accepted target candidate cell. The gNB-CU sends a UE CONTEXT MODIFICATION REQUEST message including the RS configuration, TCI state configuration, and RACH configuration of the collected acceptable target candidate cells from other gNB-DUs to the (source / serving) gNB-DU where the terminal device's serving cell is located. The source gNB-DU responds with a UE CONTEXT MODIFICATION RESPONSE message. The gNB-CU sends a UE CONTEXT SETUP REQUEST message including the cell ID of the prepared candidate cell and the associated RS configuration of each candidate cell from the other candidate gNB-DUs to the (candidate) gNB-DU. The (candidate) gNB-DU responds with a UE CONTEXT MODIFICATION RESPONSE message including the updated low-layer RRC configuration. The gNB-CU sends a DL RRC MESSAGE TRANSFER message to the source gNB-DU, including the generated RRCReconfiguration message carrying the LTM configuration. The source gNB-DU forwards the received RRCReconfiguration message to the UE.

[0189] In some embodiments, the terminal device does not support CHO and LTM simultaneously.

[0190] The network device receives a measurement report message from the terminal device, and sends a CHO configuration to the terminal device.

[0191] Alternatively, when the network device receives a measurement report message from the terminal device, if the terminal device is configured with LTM, the network device does not send the CHO configuration to the terminal device. Alternatively, the network device releases the LTM configuration and sends the CHO configuration to the terminal device.

[0192] For example, the network device is a gNB.

[0193] For example, in a CU-DU split scenario, the gNB-CU decides to initiate CHO configuration. The gNB-CU sends a UE CONTEXT SETUP REQUEST message to the candidate gNB-DU to create a UE uplink context and establish one or more data bearers. The candidate gNB-DU responds with a UE CONTEXT SETUP RESPONSE message that includes the target cell ID requested by the gNB-CU. The gNB-CU sends a DL RRC MESSAGE TRANSFER message to the source gNB-DU, including the generated RRCReconfiguration message. The source gNB-DU forwards the received RRCReconfiguration message to the UE.

[0194] In some embodiments, the network device configures the conditional reconfiguration (ConditionalReconfig) of CHO or MCG for the terminal device, but does not configure LTM or LTM-Config or LTM-Candidate; and / or, the network device configures LTM or LTM-Config or LTM-Candidate for the terminal device, but does not configure the conditional reconfiguration (ConditionalReconfig) of CHO or MCG.

[0195] In some embodiments, the terminal device supports both CHO and LTM; the network device configures a first cell as a CHO candidate cell and a second cell as an LTM candidate cell for the terminal device, and the first cell and the second cell are different cells.

[0196] In some embodiments, the network device does not configure the first cell as an LTM candidate cell, and the network device does not configure the second cell as a CHO candidate cell.

[0197] In some embodiments, the network device is a gNB, or a gNB-CU of a serving cell, or a gNB-CU of a source cell, or a gNB-DU of a candidate cell.

[0198] In some embodiments, the network device configures a first value for the timer T304 or the first timer, the first value being applicable to both the LTM based on random access and the LTM based on non-random access;

[0199] or,

[0200] The network device configures a second value and a third value for the timer T304 or the first timer, wherein the second value is applicable to LTM based on random access, and the third value is applicable to LTM based on non-random access.

[0201] In some embodiments, the configuration of the network device includes: configuring CHO priority on the network device; and / or configuring attemptCondReconfig on the network device but not configuring attemptLTM-Switch; and / or configuring the network device to release LTM configuration.

[0202] In some embodiments, the configuration of the network device includes: configuring LTM priority on the network device; and / or configuring attemptLTM-Switch but not configuring attemptCondReconfig on the network device; and / or configuring releasing CHO configuration on the network device.

[0203] The above embodiments are merely exemplary of the present invention, but the present invention is not limited thereto. Appropriate modifications may be made based on the above embodiments. For example, the above embodiments may be used alone, or one or more of the above embodiments may be combined.

[0204] It can be seen from the above embodiments that, through the embodiments of the present application, a cell is not configured as a CHO candidate cell and an LTM candidate cell at the same time, or, according to the configuration of the network device, attempts to execute CHO or attempts to execute LTM, and the terminal device can perform rapid failure recovery, thereby reducing service interruption time and improving user experience.

[0205] Embodiments of the fourth aspect

[0206] The embodiment of the present application provides a configuration method, which is described from the perspective of a network device. The embodiment of the fourth aspect can be performed independently or combined with the embodiments of the first to third aspects. The same contents as the embodiments of the first to third aspects will not be repeated.

[0207] In some embodiments, the network device configures a first value for the timer T304 or the first timer, where the first value is applicable to both the LTM based on random access and the LTM based on non-random access.

[0208] In some embodiments, the network device configures a second value and a third value for the timer T304 or the first timer, wherein the second value is applicable to LTM based on random access, and the third value is applicable to LTM based on non-random access.

[0209] In some embodiments, the first timer may be a timer different from timer T304. The first timer may be configured independently of T304, for example, if the first timer is configured with a first value, T304 may also be configured with the first value; or if the first timer is configured with a first value, T304 may be configured with a second value or a third value, etc.

[0210] In some embodiments, the first timer can be configured in association with T304, for example, if the first timer is configured with a first value, then T304 is also configured with the first value; or if the first timer is configured with a second value, then T304 is configured with a third value, and so on.

[0211] For example, the terminal device releases the LTM configuration when at least one of the following events occurs: handover (L3HO / CHO / LTM) execution (e.g., T304 start / run), radio link failure triggering and / or handover failure (e.g., T304 timeout), RRC connection reestablishment process initiation (e.g., T311 start / run).

[0212] For another example, the terminal device releases the CHO configuration when at least one of the following events occurs: handover (L3HO / CHO / LTM) execution, radio link failure triggering and / or handover failure (T304 timeout), RRC connection reestablishment process initiation.

[0213] In some embodiments, when the LTM cell change is executed, the timer T304 is started; or when the LTM cell change is executed, the first timer is started.

[0214] In some embodiments, when the timer T304 or the first timer times out, the handover is considered to have failed.

[0215] The above embodiments are merely exemplary of the present invention, but the present invention is not limited thereto. Appropriate modifications may be made based on the above embodiments. For example, the above embodiments may be used individually, or one or more of the above embodiments may be combined.

[0216] Embodiments of the fifth aspect

[0217] The embodiments of the present application provide an apparatus for configuring a candidate cell or an apparatus for applying a candidate cell. The apparatus may be, for example, a terminal device, or one or more components or assemblies configured in the terminal device, and the contents identical to those in the first to third aspects of the embodiments are not repeated here.

[0218] FIG9 is a schematic diagram of an apparatus for configuring or applying a candidate cell according to an embodiment of the present application. As shown in FIG9 , an apparatus 900 for configuring or applying a candidate cell includes: a receiving unit 901 and a processing unit 902 .

[0219] In some embodiments, the receiving unit 901 receives configuration information of a configured candidate cell sent by a network device; wherein a cell is not simultaneously configured as a conditional handover (CHO) candidate cell and a layer 1 / layer 2 triggered mobility (LTM) candidate cell of the terminal device.

[0220] In some embodiments, the terminal device does not support CHO and LTM simultaneously;

[0221] The terminal device is configured with CHO or MCG conditional reconfiguration (ConditionalReconfig), but is not configured with LTM or LTM-Config or LTM-Candidate; and / or

[0222] If the terminal device is configured with LTM, LTM-Config, or LTM-Candidate, it is not configured with the conditional reconfiguration (ConditionalReconfig) of CHO or MCG.

[0223] In some embodiments, the terminal device supports both CHO and LTM;

[0224] The first cell of the terminal device is a CHO candidate cell, the second cell is an LTM candidate cell, and the first cell and the second cell are different cells.

[0225] In some embodiments, the first cell is not configured as an LTM candidate cell by the network device, and the second cell is not configured as a CHO candidate cell by the network device.

[0226] In some embodiments, the network device is a gNB, or a gNB-CU of a serving cell, or a gNB-CU of a source cell, or a gNB-DU of a candidate cell.

[0227] In some embodiments, the first cell is also configured by the network device as an LTM candidate cell, or the second cell is also configured by the network device as a CHO candidate cell, then the terminal device releases the LTM configuration or CHO configuration when switching is performed or when a radio link failure is triggered or when switching fails or when an RRC connection reconstruction process is initiated.

[0228] In some embodiments, the handover failure includes timer T304 or a first timer timing out, the first timer being different from the timer T304;

[0229] When the LTM cell change is executed, the timer T304 is started; or when the LTM cell change is executed, the first timer is started.

[0230] In some embodiments, the timer T304 or the first timer is configured with a first value, applicable to LTM based on random access and LTM based on non-random access; or

[0231] The timer T304 or the first timer is configured with a second value and a third value, the second value is applicable to LTM based on random access, and the third value is applicable to LTM based on non-random access.

[0232] In some embodiments, the processing unit 902 initiates RRC connection reestablishment after a radio link failure; wherein,

[0233] If the cell selected in the cell selection is a CHO candidate cell, the terminal device attempts to perform CHO; if the cell selected in the cell selection is an LTM candidate cell, the terminal device attempts to perform LTM;

[0234] The radio link failure includes: RLF of the source cell when CHO is configured, or RLF when LTM is configured, or RLF of the source cell when LTM is configured, or RLF of the target cell when LTM is configured.

[0235] In some embodiments, the processing unit 902 initiates RRC connection reestablishment after LTM failure; wherein,

[0236] If the cell selected in the cell selection is a CHO candidate cell, the terminal device attempts to perform CHO; if the cell selected in the cell selection is an LTM candidate cell, the terminal device attempts to perform LTM;

[0237] Alternatively, if the cell selected in the cell selection is an LTM candidate cell, the terminal device attempts to perform LTM; otherwise, the terminal device sends an RRC re-establishment request.

[0238] In some embodiments, the processing unit 902 initiates RRC connection reestablishment after a handover failure, wherein:

[0239] If the cell selected in the cell selection is a CHO candidate cell, the terminal device attempts to perform CHO; if the cell selected in the cell selection is an LTM candidate cell, the terminal device attempts to perform LTM;

[0240] Alternatively, if the cell selected in the cell selection is a CHO candidate cell, the terminal device attempts to perform CHO; otherwise, the terminal device sends an RRC re-establishment request;

[0241] In some embodiments, the switching includes at least one of the following:

[0242] reconfiguration with synchronization;

[0243] L3 synchronous reconfiguration;

[0244] Network-triggered L3 synchronous reconfiguration of MCG;

[0245] Conditional synchronous reconfiguration of MCG;

[0246] Conditional synchronous reconfiguration of MCG including conditional synchronous reconfiguration of SCG;

[0247] L1 / L2 Triggered Mobility (LTM) for MCG.

[0248] In some embodiments, the receiving unit 901 receives configuration information of candidate cells sent by the network device; and the processing unit 902 attempts to perform CHO or LTM according to regulations or based on the implementation of the terminal device or according to the configuration of the network device.

[0249] In some embodiments, the processing unit 902 is also used to: initiate RRC connection reconstruction after a wireless link failure or a handover failure; perform cell selection; and according to the selected cell, attempt to perform CHO or attempt to perform LTM in accordance with regulations or based on the implementation of the terminal device or according to the configuration of the network device.

[0250] In some embodiments, the radio link failure includes: RLF of the source cell when CHO is configured, or RLF when LTM is configured, or RLF of the source cell when LTM is configured, or RLF of the target cell when LTM is configured;

[0251] The switching includes at least one of the following:

[0252] reconfiguration with synchronization;

[0253] L3 synchronous reconfiguration;

[0254] Network-triggered L3 synchronous reconfiguration of MCG;

[0255] Conditional synchronous reconfiguration of MCG;

[0256] Conditional synchronous reconfiguration of MCG including conditional synchronous reconfiguration of SCG;

[0257] L1 / L2 Triggered Mobility (LTM) for MCG.

[0258] In some embodiments, the processing unit 902 attempts to execute CHO or attempts to execute LTM in accordance with regulations, including: if the cell selected in the cell selection is an LTM candidate cell, the terminal device attempts to execute LTM; otherwise, if the cell selected in the cell selection is a CHO candidate cell, the terminal device attempts to execute CHO; otherwise, the terminal device sends an RRC reconstruction request.

[0259] In some embodiments, the processing unit 902 attempts to perform LTM based on the implementation of the terminal device, including: LTM execution does not include RLC reconstruction and / or PDCP data recovery, then attempting to perform LTM; and / or, LTM configuration includes non-contention random access (CFRA) configuration, then attempting to perform LTM.

[0260] In some embodiments, the processing unit 902 attempts to perform CHO based on the implementation of the terminal device, including: LTM execution includes RLC reconstruction and / or PDCP data recovery, then attempting to perform CHO; and / or, LTM configuration does not include non-contention random access (CFRA) configuration, then attempting to perform CHO.

[0261] In some embodiments, the processing unit 902 attempts to perform CHO according to the configuration of the network device, and CHO is prioritized by the network device configuration; and / or, the network device configures attemptCondReconfig but not attemptLTM-Switch; and / or, the LTM configuration is released by the network device.

[0262] In some embodiments, the processing unit 902 attempts to execute LTM according to the configuration of the network device, and LTM is prioritized by the network device configuration; and / or, the network device configures attemptLTM-Switch but does not configure attemptCondReconfig; and / or, the CHO configuration is released by the network device.

[0263] It is worth noting that the above only describes the components or modules related to the present application, but the present application is not limited thereto. The apparatus 900 for configuring or applying a candidate cell may also include other components or modules. For the specific contents of these components or modules, reference may be made to the relevant art.

[0264] In addition, for the sake of simplicity, FIG9 only illustrates the connection relationship or signal direction between various components or modules. However, it should be clear to those skilled in the art that various related technologies such as bus connection can be used. The above-mentioned components or modules can be implemented by hardware facilities such as processors, memories, transmitters, and receivers; the implementation of this application is not limited to this.

[0265] Through the embodiments of the present application, a cell is not configured as a CHO candidate cell and an LTM candidate cell at the same time, or attempts to execute CHO or attempts to execute LTM according to the configuration of the network device. The terminal device can perform rapid failure recovery, thereby reducing service interruption time and improving user experience.

[0266] Embodiments of the sixth aspect

[0267] The embodiment of the present application provides an apparatus for configuring candidate cells. The apparatus may be, for example, a network device, or one or more components or assemblies configured on the network device. The contents that are the same as those in the first to fourth aspects of the embodiment are not repeated here.

[0268] FIG10 is a schematic diagram of an apparatus for configuring candidate cells according to an embodiment of the present application. As shown in FIG10 , the apparatus 1000 for configuring candidate cells includes:

[0269] A sending unit 1001, which sends configuration information of configuring candidate cells to a terminal device;

[0270] In which, a cell is not configured as a conditional handover (CHO) candidate cell and a layer 1 / layer 2 triggered mobility (LTM) candidate cell of the terminal device at the same time, or the terminal device attempts to perform CHO or attempts to perform LTM according to the configuration of the network device.

[0271] In some embodiments, the terminal device does not support CHO and LTM simultaneously;

[0272] The network device configures the conditional reconfiguration (ConditionalReconfig) of CHO or MCG for the terminal device, but does not configure LTM or LTM-Config or LTM-Candidate; and / or

[0273] The network device configures LTM or LTM-Config or LTM-Candidate for the terminal device, but does not configure the conditional reconfiguration (ConditionalReconfig) of CHO or MCG.

[0274] In some embodiments, the terminal device supports both CHO and LTM;

[0275] The network device configures a first cell as a CHO candidate cell and a second cell as an LTM candidate cell for the terminal device, where the first cell and the second cell are different cells;

[0276] The network device does not configure the first cell as an LTM candidate cell, and the network device does not configure the second cell as a CHO candidate cell.

[0277] In some embodiments, the network device is a gNB, or a gNB-CU of a serving cell, or a gNB-CU of a source cell, or a gNB-DU of a candidate cell.

[0278] In some embodiments, the network device configures a first value for the timer T304 or the first timer, the first value being applicable to both the LTM based on random access and the LTM based on non-random access;

[0279] or,

[0280] The network device configures a second value and a third value for the timer T304 or the first timer, wherein the second value is applicable to LTM based on random access, and the third value is applicable to LTM based on non-random access.

[0281] In some embodiments, the configuration of the network device includes:

[0282] The network device is configured with CHO priority; and / or, the network device is configured with attemptCondReconfig but not attemptLTM-Switch; and / or, the network device is configured to release LTM configuration.

[0283] In some embodiments, the configuration of the network device includes:

[0284] The network device is configured with LTM priority; and / or, the network device is configured with attemptLTM-Switch but not attemptCondReconfig; and / or, the network device is configured to release CHO configuration.

[0285] It is worth noting that the above only describes the components or modules related to the present application, but the present application is not limited thereto. The apparatus 1000 for configuring candidate cells may also include other components or modules, and for the specific contents of these components or modules, reference may be made to the relevant art.

[0286] In addition, for the sake of simplicity, FIG10 only illustrates the connection relationship or signal direction between various components or modules. However, it should be clear to those skilled in the art that various related technologies such as bus connection can be used. The above-mentioned components or modules can be implemented by hardware facilities such as processors, memories, transmitters, and receivers; the implementation of this application is not limited to this.

[0287] Through the embodiments of the present application, a cell is not configured as a CHO candidate cell and an LTM candidate cell at the same time, or attempts to execute CHO or attempts to execute LTM according to the configuration of the network device. The terminal device can perform rapid failure recovery, thereby reducing service interruption time and improving user experience.

[0288] Embodiments of the seventh aspect

[0289] An embodiment of the present application also provides a communication system, and reference may be made to FIG2 . The contents identical to those in the first to sixth aspects of the embodiments will not be repeated.

[0290] In some embodiments, the communication system 100 may include at least:

[0291] A network device that sends configuration information for configuring candidate cells to a terminal device;

[0292] A terminal device that receives the configuration information; wherein a cell is not configured as a conditional handover (CHO) candidate cell and a layer 1 / layer 2 triggered mobility (LTM) candidate cell of the terminal device at the same time, or the terminal device attempts to perform CHO or attempts to perform LTM according to the configuration of the network device.

[0293] An embodiment of the present application further provides a network device, which may be, for example, a base station, but the present application is not limited thereto and may also be other network devices.

[0294] Figure 11 is a schematic diagram illustrating the structure of a network device according to an embodiment of the present application. As shown in Figure 11 , network device 1100 may include a processor 1110 (e.g., a central processing unit (CPU)) and a memory 1120 ; the memory 1120 is coupled to the processor 1110 . The memory 1120 may store various data and may also store an information processing program 1130 , which is executed under the control of the processor 1110 .

[0295] For example, the processor 1110 may be configured to execute a program to implement the method for configuring a candidate cell as described in the embodiment of the third aspect. For example, the processor 1110 may be configured to perform the following control: sending configuration information for configuring a candidate cell to a terminal device; wherein a cell is not simultaneously configured as a conditional handover (CHO) candidate cell and a layer 1 / layer 2 triggered mobility (LTM) candidate cell for the terminal device, or the terminal device attempts to perform CHO or attempts to perform LTM according to the configuration of the network device.

[0296] In addition, as shown in FIG11 , the network device 1100 may further include: a transceiver 1140 and an antenna 1150, etc.; wherein, the functions of the above components are similar to those in the prior art and are not described in detail here. It is worth noting that the network device 1100 does not necessarily include all the components shown in FIG11 ; in addition, the network device 1100 may also include components not shown in FIG11 , and reference may be made to the prior art for details.

[0297] The embodiment of the present application also provides a terminal device, but the present application is not limited thereto and may also be other devices.

[0298] Figure 12 is a schematic diagram of a terminal device according to an embodiment of the present application. As shown in Figure 12 , terminal device 1200 may include a processor 1210 and a memory 1220. Memory 1220 stores data and programs and is coupled to processor 1210. It should be noted that this diagram is exemplary; other types of structures may be used to supplement or replace this structure to implement telecommunication or other functions.

[0299] For example, the processor 1210 may be configured to execute a program to implement the method for configuring a candidate cell as described in the embodiment of the first aspect. For example, the processor 1210 may be configured to perform the following control: receiving configuration information for configuring a candidate cell sent by a network device; wherein a cell is not simultaneously configured as a conditional handover (CHO) candidate cell and a layer 1 / layer 2 triggered mobility (LTM) candidate cell for the terminal device.

[0300] For another example, the processor 1210 may be configured to execute a program to implement the method for applying candidate cells as described in the embodiment of the second aspect. For example, the processor 1210 may be configured to perform the following control: receiving configuration information for configuring candidate cells sent by a network device; and attempting to perform CHO or attempting to perform LTM according to regulations, based on implementation of the terminal device, or according to the configuration of the network device.

[0301] As shown in Figure 12 , the terminal device 1200 may further include: a communication module 1230, an input unit 1240, a display 1250, and a power supply 1260. The functions of these components are similar to those in the prior art and are not described in detail here. It is worth noting that the terminal device 1200 does not necessarily include all of the components shown in Figure 12 , and these components are not essential. Furthermore, the terminal device 1200 may also include components not shown in Figure 12 , for which reference may be made to the prior art.

[0302] An embodiment of the present application also provides a computer program, wherein when the program is executed in a terminal device, the program enables the terminal device to execute the method for configuring candidate cells described in the embodiment of the first aspect or the method for applying candidate cells described in the embodiment of the second aspect.

[0303] An embodiment of the present application also provides a storage medium storing a computer program, wherein the computer program enables a terminal device to execute the method for configuring a candidate cell as described in the embodiment of the first aspect or the method for applying a candidate cell as described in the embodiment of the second aspect.

[0304] An embodiment of the present application also provides a computer program, wherein when the program is executed in a network device, the program enables the terminal device to execute the method for configuring candidate cells described in the embodiment of the third aspect.

[0305] An embodiment of the present application further provides a storage medium storing a computer program, wherein the computer program enables a network device to execute the method for configuring candidate cells described in the embodiment of the third aspect.

[0306] The above devices and methods of the present application can be implemented by hardware or by a combination of hardware and software. The present application relates to such a computer-readable program that, when executed by a logic component, enables the logic component to implement the devices or components described above, or enables the logic component to implement the various methods or steps described above. The present application also relates to a storage medium for storing the above program, such as a hard disk, a magnetic disk, an optical disk, a DVD, a flash memory, etc.

[0307] The method / device described in conjunction with the embodiments of the present application can be directly embodied as hardware, a software module executed by a processor, or a combination of the two. For example, one or more of the functional block diagrams shown in the figure and / or one or more combinations of functional block diagrams can correspond to various software modules of the computer program flow or to various hardware modules. These software modules can respectively correspond to the various steps shown in the figure. These hardware modules can be implemented by solidifying these software modules, for example, using a field programmable gate array (FPGA).

[0308] The software module may be located in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. A storage medium may be coupled to a processor so that the processor can read information from the storage medium and write information to the storage medium; or the storage medium may be an integral part of the processor. The processor and the storage medium may be located in an ASIC. The software module may be stored in the memory of the mobile terminal or in a memory card that can be inserted into the mobile terminal. For example, if the device (such as a mobile terminal) uses a large-capacity MEGA-SIM card or a large-capacity flash memory device, the software module may be stored in the MEGA-SIM card or the large-capacity flash memory device.

[0309] One or more of the functional blocks and / or one or more combinations of functional blocks described in the accompanying drawings may be implemented as a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or any appropriate combination thereof for performing the functions described in this application. One or more of the functional blocks and / or one or more combinations of functional blocks described in the accompanying drawings may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in communication with a DSP, or any other such configuration.

[0310] The present application has been described above in conjunction with specific embodiments. However, those skilled in the art should understand that these descriptions are merely illustrative and are not intended to limit the scope of protection of the present application. Those skilled in the art may make various modifications and variations to the present application based on the spirit and principles of the present application, and such modifications and variations are also within the scope of the present application.

[0311] Regarding the implementation methods including the above embodiments, the following additional notes are also disclosed:

[0312] 1. A method for configuring candidate cells, comprising:

[0313] The terminal device receives configuration information of the candidate cell sent by the network device;

[0314] Among them, a cell is not configured as a conditional handover (CHO) candidate cell and a layer 1 / layer 2 triggered mobility (LTM) candidate cell of the terminal device at the same time.

[0315] 2. A method for applying candidate cells, comprising:

[0316] The terminal device receives configuration information of the candidate cell sent by the network device; and

[0317] The terminal device attempts to execute CHO or attempts to execute LTM according to regulations or based on the implementation of the terminal device or according to the configuration of the network device.

[0318] 3. The method according to Supplementary Note 2, wherein the method further comprises:

[0319] Initiate RRC connection reestablishment after radio link failure or handover failure;

[0320] Performing cell selection; and

[0321] Depending on the selected cell, an attempt is made to perform CHO or an attempt is made to perform LTM according to regulations, based on the implementation of the terminal device, or based on the configuration of the network device.

[0322] 4. The method according to Note 3, wherein the radio link failure comprises: RLF of the source cell when CHO is configured, or RLF when LTM is configured, or RLF of the source cell when LTM is configured, or RLF of the target cell when LTM is configured;

[0323] The switching includes at least one of the following:

[0324] reconfiguration with synchronization;

[0325] L3 synchronous reconfiguration;

[0326] Network-triggered L3 synchronous reconfiguration of MCG;

[0327] Conditional synchronous reconfiguration of MCG;

[0328] Conditional synchronous reconfiguration of MCG including conditional synchronous reconfiguration of SCG;

[0329] L1 / L2 Triggered Mobility (LTM) for MCG.

[0330] 5. The method according to Supplementary Note 2, wherein the terminal device attempts to perform CHO or attempts to perform LTM according to regulations, comprising:

[0331] If the cell selected in the cell selection is an LTM candidate cell, the terminal device attempts to perform LTM;

[0332] Otherwise, if the cell selected in the cell selection is a CHO candidate cell, the terminal device attempts to perform CHO;

[0333] Otherwise, the terminal device sends an RRC re-establishment request.

[0334] 6. The method according to note 2, wherein the terminal device attempts to perform LTM based on an implementation of the terminal device, comprising:

[0335] If LTM execution does not include RLC re-establishment and / or PDCP data recovery, LTM execution is attempted; and / or if LTM configuration includes non-contention random access (CFRA) configuration, LTM execution is attempted.

[0336] 7. The method according to the supplementary note, wherein the terminal device attempts to perform CHO based on an implementation of the terminal device, comprising:

[0337] If the LTM execution includes RLC re-establishment and / or PDCP data recovery, then CHO is attempted; and / or if the LTM configuration does not include non-contention random access (CFRA) configuration, then CHO is attempted.

[0338] 8. The method according to note 2, wherein the terminal device attempts to perform CHO according to the configuration of the network device, and CHO is prioritized by the network device configuration; and / or the network device is configured with attemptCondReconfig but not attemptLTM-Switch; and / or the LTM configuration is released by the network device;

[0339] Alternatively, the terminal device attempts to execute LTM according to the configuration of the network device, and LTM is prioritized by the network device configuration; and / or, the network device is configured with attemptLTM-Switch but not attemptCondReconfig; and / or, the CHO configuration is released by the network device.

[0340] 9. A method for configuring a candidate cell, comprising:

[0341] The network device sends configuration information of the candidate cell to the terminal device;

[0342] In which, a cell is not configured as a conditional handover (CHO) candidate cell and a layer 1 / layer 2 triggered mobility (LTM) candidate cell of the terminal device at the same time, or the terminal device attempts to perform CHO or attempts to perform LTM according to the configuration of the network device.

[0343] 10. A communication system comprising:

[0344] A network device that sends configuration information for configuring candidate cells to a terminal device;

[0345] A terminal device that receives the configuration information; wherein a cell is not configured as a conditional handover (CHO) candidate cell and a layer 1 / layer 2 triggered mobility (LTM) candidate cell at the same time, or the terminal device attempts to perform CHO or attempts to perform LTM according to the configuration of the network device.

Claims

1. A device for configuring a candidate cell, comprising: A receiving unit, configured to receive configuration information of a candidate cell sent by a network device; Among them, a cell is not configured as a CHO candidate cell and an LTM candidate cell of the terminal device at the same time.

2. The device according to claim 1, wherein: The terminal device does not support CHO and LTM at the same time; The terminal device is configured with CHO or MCG conditional reconfiguration, but is not configured with LTM or LTM-Config or LTM-Candidate; and / or The terminal device is configured with LTM or LTM-Config or LTM-Candidate, and is not configured with conditional reconfiguration of CHO or MCG.

3. The device according to claim 1, wherein: The terminal device supports both CHO and LTM; The first cell of the terminal device is a CHO candidate cell, the second cell is an LTM candidate cell, and the first cell and the second cell are different cells.

4. The device according to claim 3, wherein: The first cell is not configured as an LTM candidate cell by the network device, and the second cell is not configured as a CHO candidate cell by the network device; The network device is a gNB, or a gNB-CU of a serving cell, or a gNB-CU of a source cell, or a gNB-DU of a candidate cell.

5. The device according to claim 3, wherein: The first cell is also configured as an LTM candidate cell by the network device, or the second cell is also configured as a CHO candidate cell by the network device, then the terminal device releases the LTM configuration or CHO configuration when switching is performed or when a wireless link failure is triggered or when switching fails or when an RRC connection reconstruction process is initiated.

6. The device according to claim 5, wherein: The handover failure includes timeout of timer T304 or a first timer, where the first timer is different from the timer T304; When the LTM cell change is executed, the timer T304 is started; or when the LTM cell change is executed, the first timer is started.

7. The device according to claim 6, wherein: The timer T304 or the first timer is configured with a first value, which is applicable to LTM based on random access and LTM based on non-random access; or The timer T304 or the first timer is configured with a second value and a third value, wherein the second value is applicable to LTM based on random access, and the third value is applicable to LTM based on non-random access.

8. The device according to claim 3, wherein: The device also includes: A processing unit, which initiates radio resource control connection reestablishment after a radio link fails; wherein, If the cell selected in the cell selection is a CHO candidate cell, the terminal device attempts to perform CHO; if the cell selected in the cell selection is an LTM candidate cell, the terminal device attempts to perform LTM; The radio link failure includes: radio link failure of the source cell when CHO is configured, or radio link failure when LTM is configured, or radio link failure of the source cell when LTM is configured, or radio link failure of the target cell when LTM is configured.

9. The device according to claim 3, wherein: The device also includes: A processing unit that initiates a radio resource control connection reestablishment after an LTM failure; wherein, If the cell selected in the cell selection is a CHO candidate cell, the terminal device attempts to perform CHO; if the cell selected in the cell selection is an LTM candidate cell, the terminal device attempts to perform LTM; Alternatively, if the cell selected in the cell selection is an LTM candidate cell, the terminal device attempts to execute LTM; otherwise, the terminal device sends a radio resource control reestablishment request.

10. The device according to claim 3, wherein: The device also includes: A processing unit, which initiates a radio resource control connection reestablishment after a handover failure, wherein: If the cell selected in the cell selection is a CHO candidate cell, the terminal device attempts to perform CHO; if the cell selected in the cell selection is an LTM candidate cell, the terminal device attempts to perform LTM; Alternatively, if the cell selected in the cell selection is a CHO candidate cell, the terminal device attempts to perform CHO; otherwise, the terminal device sends an RRC reestablishment request.

11. The device according to claim 10, wherein: The switching includes at least one of the following: Synchronous reconfiguration; L3 synchronous reconfiguration; Network-triggered L3 synchronous reconfiguration of MCG; Conditional synchronous reconfiguration of MCG; Conditional synchronous reconfiguration of MCG including conditional synchronous reconfiguration of SCG; L1 / L2 triggered mobility for MCG.

12. A device for applying a candidate cell, comprising: A receiving unit, configured to receive configuration information of a candidate cell sent by a network device; as well as A processing unit which attempts to execute CHO or attempts to execute LTM according to regulations or based on the implementation of the terminal device or according to the configuration of the network device.

13. An apparatus for configuring a candidate cell, comprising: A sending unit, which sends configuration information of configuring a candidate cell to a terminal device; A cell is not configured as a CHO candidate cell and an LTM candidate cell of the terminal device at the same time, or the terminal device attempts to execute CHO or attempts to execute LTM according to the configuration of the network device.

14. The device according to claim 13, wherein: The terminal device does not support CHO and LTM at the same time; The network device configures the conditional reconfiguration of CHO or MCG for the terminal device, but does not configure LTM or LTM-Config or LTM-Candidate; and / or The network device configures LTM or LTM-Config or LTM-Candidate for the terminal device, and does not configure the conditional reconfiguration of CHO or MCG.

15. The device according to claim 13, wherein: The terminal device supports both CHO and LTM; The network device configures a first cell as a CHO candidate cell and a second cell as an LTM candidate cell for the terminal device, and the first cell and the second cell are different cells.

16. The device according to claim 15, wherein: The network device does not configure the first cell as an LTM candidate cell, and the network device does not configure the second cell as a CHO candidate cell.

17. The device according to claim 13, wherein: The network device is a gNB, or a gNB-CU of a serving cell, or a gNB-CU of a source cell, or a gNB-DU of a candidate cell.

18. The device according to claim 13, wherein: The network device configures a first value for the timer T304 or the first timer, wherein the first value is applicable to the LTM based on random access and the LTM based on non-random access; or, The network device configures a second value and a third value for the timer T304 or the first timer, wherein the second value is applicable to LTM based on random access, and the third value is applicable to LTM based on non-random access.

19. The device according to claim 13, wherein: The configuration of the network device includes: The network device is configured with CHO priority; and / or, the network device is configured with attemptCondReconfig but not attemptLTM-Switch; and / or, the network device is configured to release the LTM configuration.

20. The device according to claim 13, wherein: The configuration of the network device includes: The network device is configured with LTM priority; and / or, the network device is configured with attemptLTM-Switch but not attemptCondReconfig; and / or, the network device is configured with release CHO configuration.

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