Low layer mobility

Abstract

Example embodiments of the present disclosure relate to devices, methods, apparatuses, and computer readable storage media for low level mobility (LLM). The method comprises: at a terminal device, sending a capability indication of recovering a source cell configuration based on a compatibility check of a target cell configuration to a first network device providing a source cell for the terminal device; receiving at least one target cell configuration for the LLM from the first network device; performing compatibility check on the at least one target cell configuration based on the configuration state of the terminal device; and resuming the data transmission based on the resumed source cell configuration in accordance with a determination that the compatibility check fails. In this manner, the LLM process may support reconfiguration failure handling, and may reduce service interruption and signaling overhead.

Description

Technical Field

[0001] Embodiments of the present disclosure relate generally to the field of telecommunications, and in particular, to devices, methods, apparatuses, and computer-readable storage media for low layer mobility (LLM). Background Art

[0002] Low Layer Mobility (LLM) aims to improve the overall robustness and performance of 5G New Radio (NR) systems. In the LLM scenario, handover from a source cell to a target cell is controlled by the network (e.g., a low-layer entity such as a distributed unit (DU)) using configuration changes. Compared to traditional scenarios including classic and conditional handover procedures, handover decisions for LLM are based on instantaneous layer 1 (i.e., L1) measurements rather than layer 3 (i.e., L3) measurements, so LLM is also called L1-centric mobility. Since time-triggered (TTT) or L3 filtering is not used, handover back to the source cell or handover between a set of serving cells can be supported during the LLM process. Summary of the invention

[0003] In general, example embodiments of the present disclosure provide a solution for reconfiguration failure handling of an LLM process.

[0004] In a first aspect, a terminal device is provided. The terminal device comprises: at least one processor; and at least one memory comprising computer program code; the at least one memory and the computer program code are configured to, together with the at least one processor, enable the terminal device to at least: send a capability indication to a first network device providing a source cell for the terminal device to restore a source cell configuration based on a compatibility check of a target cell configuration for a low layer mobility LLM process; receive at least one target cell configuration for the LLM process from the first network device; perform a compatibility check on at least one target cell configuration based on a configuration state of the terminal device; and resume data transmission based on a determination of a compatibility check failure based on the restored source cell configuration.

[0005] In a second aspect, a first network device is provided. The first network device includes: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code are configured to, together with the at least one processor, enable the first network device to at least: receive a capability indication for restoring a source cell configuration based on a compatibility check for a target cell configuration for a low layer mobility LLM process from a terminal device, the terminal device being in a source cell provided by the first network device; send a capability indication to a second network device that manages the first network device; and send at least one target cell configuration for the LLM process to the terminal device based on a determination that the LLM will be triggered, the at least one target cell configuration being acquired from the second network device.

[0006] In a third aspect, a second network device is provided. The second network device includes: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code are configured to, together with the at least one processor, enable the second network device to at least: receive a capability indication of recovering a source cell based on a compatibility check of a target cell configuration for a low layer mobility LLM process from one of a first network device or a terminal device, the first network device being managed by the second network device and providing the source cell for the terminal device; determine at least one target cell configuration for the LLM process based on the capability indication according to a determination that the LLM will be triggered for the terminal device; and send at least one target cell configuration to the first network device.

[0007] In a fourth aspect, a method is provided. The method comprises: at a terminal device, sending a capability indication to restore a source cell configuration based on a compatibility check of a target cell configuration for a low layer mobility (LLM) procedure to a first network device that provides a source cell for the terminal device; receiving at least one target cell configuration for the LLM procedure from the first network device; performing a compatibility check on the at least one target cell configuration based on a configuration state of the terminal device; and resuming data transmission based on a determination of a compatibility check failure, based on the restored source cell configuration.

[0008] In a fifth aspect, a method is provided. The method comprises: receiving, at a first network device, a capability indication for recovering a source cell configuration based on a compatibility check of a target cell configuration for a low layer mobility LLM procedure from a terminal device, the terminal device being in a source cell provided by the first network device; sending the capability indication to a second network device that manages the first network device; and sending, based on a determination that LLM will be triggered for the terminal device, at least one target cell configuration for the LLM procedure to the terminal device, the at least one target cell configuration being acquired from the second network device.

[0009] In a sixth aspect, a method is provided. The method comprises: receiving, at a second network device, a capability indication for recovering a source cell based on a compatibility check of a target cell configuration for a low layer mobility LLM procedure from one of a first network device or a terminal device, the first network device being managed by the second network device and providing a source cell for the terminal device; determining, based on a determination that LLM will be triggered for the terminal device, at least one target cell configuration for the LLM procedure based on the capability indication; and sending the at least one target cell configuration to the first network device.

[0010] In a seventh aspect, a first device is provided. The first device includes: a component for sending a capability indication to a second device that provides a source cell for the first device based on a compatibility check of a target cell configuration for a low layer mobility (LLM) process to restore a source cell configuration; a component for receiving at least one target cell configuration for the LLM process from the second device; a component for performing a compatibility check on at least one target cell configuration based on a configuration state of the first device; and a component for resuming data transmission based on a restored source cell configuration according to a determination of a compatibility check failure.

[0011] In an eighth aspect, a second device is provided. The second device includes: a component for receiving a capability indication for recovering a source cell configuration based on a compatibility check of a target cell configuration for a low layer mobility LLM process from a first device, the first device being in a source cell provided by the second device; a component for sending the capability indication to a third device that manages the second device; and a component for sending at least one target cell configuration for the LLM process to the first device based on a determination that the LLM will be triggered for the first device, the at least one target cell configuration being acquired from the third device.

[0012] In a ninth aspect, a third device is provided. The third device includes: a component for receiving a capability indication of a source cell based on a compatibility check of a target cell configuration for a low layer mobility LLM process from one of a first device or a second device, the second device being managed by the third device and providing a source cell for the first device; a component for determining at least one target cell configuration for the LLM process based on the capability indication according to a determination that the LLM will be triggered for the first device; and a component for sending at least one target cell configuration to the second device.

[0013] In a tenth aspect, there is provided a computer readable medium having stored thereon a computer program which, when executed by at least one processor of a device, causes the device to perform the method according to the fourth aspect.

[0014] In an eleventh aspect, there is provided a computer readable medium having stored thereon a computer program which, when executed by at least one processor of a device, causes the device to perform the method according to the fifth aspect.

[0015] In a twelfth aspect, there is provided a computer readable medium having stored thereon a computer program which, when executed by at least one processor of a device, causes the device to perform the method according to the sixth aspect.

[0016] Other features and advantages of the embodiments of the present disclosure will also be apparent from the following description of specific embodiments when read in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the embodiments of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Embodiments of the present disclosure are presented below in the form of examples and their advantages are explained in more detail with reference to the accompanying drawings, in which:

[0018] Figure 1 An example network system is shown in which example embodiments of the present disclosure may be implemented;

[0019] Figure 2 shows a signaling diagram illustrating an example LLM procedure according to some example embodiments of the present disclosure;

[0020] Figure 3A shows a signaling diagram illustrating another example LLM process according to some example embodiments of the present disclosure;

[0021] Figure 3B shows a signaling diagram illustrating another example LLM process according to some example embodiments of the present disclosure;

[0022] Figure 4 A flowchart illustrating an example method according to some example embodiments of the present disclosure;

[0023] Figure 5 A flowchart illustrating an example method according to some example embodiments of the present disclosure;

[0024] Figure 6 A flowchart illustrating an example method according to some example embodiments of the present disclosure;

[0025] Figure 7 shows a simplified block diagram of a device suitable for implementing an example embodiment of the present disclosure; and

[0026] Figure 8 A block diagram of an example computer-readable medium is shown in accordance with some embodiments of the present disclosure.

[0027] Throughout the drawings, the same or similar reference numerals refer to the same or similar elements. DETAILED DESCRIPTION

[0028] The principles of the present disclosure will now be described with reference to some example embodiments. It should be understood that these embodiments are described only for illustrative purposes, and help those skilled in the art to understand and implement the present disclosure without proposing any limitation to the scope of the present disclosure. The present disclosure described herein can be implemented in various ways except for the way described below.

[0029] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0030] References in this disclosure to "one embodiment," "an embodiment," "an example embodiment," etc. indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes the particular feature, structure, or characteristic. Furthermore, these phrases do not necessarily refer to the same embodiment. In addition, when a particular feature, structure, or characteristic is described in conjunction with an example embodiment, it is recognized by those skilled in the art that, whether or not explicitly described, it is within the knowledge of those skilled in the art to affect such feature, structure, or characteristic in conjunction with other embodiments.

[0031] It should be understood that although the terms "first" and "second" etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish the functionality of the various elements. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0032] The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the exemplary embodiments. As used herein, the singular forms "a", "an", and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include", "comprise", "have", "have", "include" and / or "comprising" when used herein specify the presence of the features, elements, and / or components, etc., but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0033] As used in this application, the term "circuitry" may refer to one or more or all of the following:

[0034] (a) hardware circuit implementation only (such as implementation in analog and / or digital circuitry only), and

[0035] (b) a combination of hardware circuitry and software such as (where applicable):

[0036] (i) a combination of analog and / or digital hardware circuits and software / firmware, and

[0037] (ii) any portion of a hardware processor(s) with software (including

[0038] digital signal processor(s), software, and memory(s) that work together to enable a device (such as a mobile phone or server) to perform various functions), and

[0039] (c) Hardware circuit(s) and / or processor(s), such as microprocessor(s) or portion(s) of microprocessor(s), that require software (e.g., firmware) to operate, but which may not be present when the software is not required for operation.

[0040] This definition of circuitry applies to all uses of the term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of only a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its accompanying software and / or firmware. For example, if applicable to a particular claim element, the term circuitry also covers a baseband integrated circuit or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, cellular network device, or other computing or network device.

[0041] As used herein, the term "communication network" refers to a network that complies with any suitable communication standard, such as a fifth generation (5G) system, long term evolution (LTE), advanced LTE (LTE-A), wideband code division multiple access (WCDMA), high speed packet access (HSPA), narrowband Internet of Things (NB-IoT), etc. In addition, the communication between the terminal device and the network device in the communication network can be performed according to any suitable generation of communication protocol, including but not limited to the first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G) new radio (NR) communication protocol, and / or any other protocol currently known or to be developed in the future. The embodiments of the present disclosure can be applied to various communication systems. In view of the rapid development of communication, there will certainly be future types of communication technologies and systems that can be used to implement the present disclosure. The scope of the present disclosure should not be limited to the above-mentioned system.

[0042] As used herein, the term "network device" refers to a node in a communication network through which a terminal device accesses the network and receives services from the network. A network device may refer to a base station (BS) or an access point (AP), for example, a NodeB (NodeB or NB), an evolved NodeB (eNodeB or eNB), a NR next generation NodeB (gNB), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), an integrated access and backhaul (IAB) node, a relay, a low power node (such as a femto, pico), etc., depending on the terminology and technology applied. A network device is allowed to be defined as part of a gNB, for example in a CU / DU split, in which case the network device is defined as a gNB-CU or a gNB-DU.

[0043] The term "terminal device" refers to any terminal device capable of wireless communication. As an example and not limitation, the terminal device may also be referred to as a communication device, a user equipment (UE), a subscriber station (SS), a portable subscriber station, a mobile station (MS), or an access terminal (AT). The terminal device may include, but is not limited to, a mobile phone, a cellular phone, a smart phone, a voice over IP (VoIP) phone, a wireless local loop phone, a tablet computer, a wearable terminal device, a personal digital assistant (PDA), a portable computer, a desktop computer, an image capture terminal device (such as a digital camera), a game terminal device, a music storage and playback appliance, a vehicle-mounted wireless terminal device, a wireless endpoint, a mobile station, a notebook embedded device (LEE), a notebook mounted device (LME), a USB dongle, a smart device, a wireless client device (CPE), an Internet of Things (IoT) device, a watch or other wearable device, a head mounted display (HMD), a vehicle, a drone, medical equipment and applications (e.g., remote surgery), industrial equipment and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated processing chain environments), consumer electronic devices, equipment operating in commercial and / or industrial wireless networks, etc. The terminal device may also correspond to the mobile terminal (MT) part of an integrated access and backhaul (IAB) node (also known as a relay node). In the following description, the terms "terminal device", "communication device", "terminal", "user equipment" and "UE" may be used interchangeably.

[0044] Although in various example embodiments, the functions described herein may be performed in fixed and / or wireless network nodes, in other example embodiments, the functions may be implemented in a user equipment device (such as a mobile phone, or a tablet, or a laptop, or a desktop computer, or a mobile IoT device, or a fixed IoT device). The user equipment device may, for example, be equipped with corresponding capabilities (as described) associated with (multiple) fixed and / or wireless network nodes as required. The user equipment device may be a user device and / or a control device, such as a chipset or a processor, which is configured to control the user device when installed in the user device. Examples of such functions include boot server functions and / or home user servers, which may be implemented in the user equipment device by providing a user equipment device having software configured to cause the user equipment device to execute from the perspective of these functions / nodes.

[0045] Whether it is L3 mobility or LLM, during handover, if the UE applies a new configuration in its internal modules, this may cause failures for certain internal operations, because the internal state may have been transferred to some "unstable" state due to the new configuration, so it cannot be restored to the original state. In this case, reconfiguration failure may occur.

[0046] In order to restore the radio link, the UE will usually perform a reestablishment procedure. Specifically, the UE can use the stored configuration to start the reestablishment procedure and release all configurations except the security and signaling radio bearer (SRB) configurations. Therefore, during the reestablishment procedure, a new target cell is selected based on the security and SRB configurations without user plane communication. After the network device sends a radio resource control (RRC) reconfiguration, the user plane and data transmission can be restored.

[0047] Obviously, the reestablishment process for reconfiguration failure will bring a lot of service interruption time and signaling overhead to the UE. In addition, the reestablishment process may cause the UE to select the previous cell (ie, the source cell).

[0048] However, in the LLM scenario, the re-establishment process may be unnecessary for reconfiguration failure. This is because the LLM process is usually triggered in the early stage when the current cell (i.e., the source cell) is in stable and good coverage conditions. If a reconfiguration failure occurs, falling back to the source cell is more desirable than the re-establishment process in terms of minimizing service interruption time and signaling overhead. Therefore, it is necessary to improve the ability to handle reconfiguration failure for LLM.

[0049] To address the above and other potential problems, embodiments of the present disclosure provide a mechanism for handling reconfiguration failures during an LLM process. According to the mechanism, the UE is enhanced with the ability to perform compliance checks on the configuration of a potential target cell before switching. By verifying the suitability for the current state of the device, the UE can revert to the original configuration in the event of a reconfiguration failure and avoid performing a reconstruction process. Therefore, the service interruption time caused by the reconfiguration failure is reduced, while improving the performance and robustness of the communication system.

[0050] Figure 1 An example network system 100 is shown in which example embodiments of the present disclosure may be implemented. Figure 1 As shown, the communication network 100 may include: a terminal device 110 , a first network device 120 , a second network device 130 , and a third network device 122 .

[0051] The second network device 130 acts as a centralized unit (CU), and the first and third network devices 120 and 122 act as DUs managed by the CU. In the context of the present disclosure, the terminal device 110, the first network device 120, the second network device 130, and the third network device 122 may also be referred to as UE 110, DU 120, CU 130, and DU 122, respectively.

[0052] Terminal device 110 may operate in a current configuration state, including but not limited to a multiple-input multiple-output (MIMO) configuration. Figure 1As shown, the terminal device 110 is located within the coverage of the cell 102 provided by the first network device 120 and is served by the first network device 120. In addition, the third network device 122 provides a cell 104. Hereinafter, the cell 102 may also be referred to as a source cell or a serving cell 102, and the cell 104 may also be referred to as a target cell 104 or a potential target cell 104.

[0053] The first network device 120 and the second network device 130 may communicate with the terminal device 110. As described above, the LLM from the source cell 102 to the potential target cell 104 may be controlled by the network, for example, by the first network device 120 and the second network device 130.

[0054] In the case where LLM is to be triggered, L1 / L2 mobility preparation may be implemented. For example, at least one target cell configuration is determined for the LLM process. In some embodiments, before switching to the target cell 104, the terminal device 110 may pre-check the compatibility of the target cell configuration with the current configuration state, which will be discussed in detail below.

[0055] It should be understood that Figure 1 The number of network devices and terminal devices shown in FIG. 1 is given for illustrative purposes and does not represent any limitation. Communication network 100 may include any suitable number of network devices and terminal devices.

[0056] According to the communication technology, the communication network 100 can be: code division multiple access (CDMA) network, time division multiple access (TDMA) network, frequency division multiple access (FDMA) network, orthogonal frequency division multiple access (OFDMA) network, single carrier frequency division multiple access (SC-FDMA) network or any other network. The communication discussed in the network 100 can meet any suitable standard, including but not limited to: new radio access (NR), long term evolution (LTE), evolved LTE, advanced LTE (LTE-A), wideband code division multiple access (WCDMA), code division multiple access (CDMA), cdma2000, and global mobile communication system (GSM), etc. In addition, the communication can be performed according to any generation of communication protocols currently known or developed in the future. Examples of communication protocols include but are not limited to: first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G) communication protocols. The technology described herein can be used for the above-mentioned wireless network and radio technology, as well as other wireless networks and radio technologies. For clarity, certain aspects of the techniques are described below for LTE, and LTE terminology is used in much of the description below.

[0057] The following will refer to Figures 2 to 6The principles and implementations of the present disclosure are described in detail. Figure 2 A signaling diagram illustrating an example LLM process 200 according to some example embodiments of the present disclosure is shown. The process 200 may involve Figure 1 The terminal device 110, the first network device 120, the second network device 130, and the third network device 122 are shown. For discussion, reference will be made to Figure 1 The process 200 is described below.

[0058] In process 200, before triggering the LLM process, a compatibility check for at least one target cell configuration of the LLM process is performed. Specifically, the terminal device 110 sends 202 to the first network device 120 a capability indication for restoring the source cell configuration based on the compatibility check for the target cell configuration of the LLM process.

[0059] In some example embodiments, the capability indication may indicate that the terminal device 110 is able to perform a pre-check by applying the target cell configuration without switching to the target cell. In other words, the terminal device 110 may verify suitability for the current state of the device before switching to the target cell 104. Thus, in the event of a reconfiguration failure, the terminal device 110 may revert to the original configuration as part of the compatibility check.

[0060] In some embodiments, the capability indication may be sent as part of the UE capability indication in an RRC message. For example, the RRC message may be an RRC connection setup complete message. In response to receiving the capability indication, the first network device 120 sends 204 the capability indication to the second network device 130.

[0061] In some cases, the network may instruct the UE to verify the configuration compatibility of the potential target cell 104 as part of the RRC configuration to activate the pre-check function. Thus, in some embodiments, the terminal device 110 may receive an instruction from one of the first network device 120 and the second network device 130 to verify the compatibility of the target cell configuration for the LLM procedure.

[0062] Based on the L1 measurements, the network may determine that LLM from source cell 102 to potential target cell 104 will be triggered for terminal device 110. In this case, first network device 120, second network device 130, and third network device 122 may prepare 206 for LLM.

[0063] In an embodiment of determining to trigger LLM, second network device 130 determines at least one target cell configuration for the LLM process based on the capability indication. For example, the at least one target cell configuration may correspond to target cell 104 provided by third network device 130. Second network device 130 sends 208 the at least one target cell configuration to first network device 120.

[0064] After receiving the at least one target cell configuration, the first network device 120 sends 210 the at least one target cell configuration to the terminal device 110. In some embodiments, the at least one target cell configuration may be sent in an RRC reconfiguration message. As an example, an example format of the RRC reconfiguration message may be "L1 / L2 config, FastRecovery=ALLOWED".

[0065] The terminal device 110 performs 212 a compatibility check on at least one target cell configuration based on a configuration state of the terminal device 110. The configuration state of the terminal device 110 may include, but is not limited to, a MIMO configuration of the terminal device 110.

[0066] In some example embodiments, the terminal device 110 may apply at least one target cell configuration and retain the source cell configuration based on the configuration state of the terminal device 110 .

[0067] In some embodiments, if the compatibility check fails, the terminal device 110 may send 214 a first message to the first network device 120. The first message may be, for example, a compliance check report sent in an RRC reconfiguration complete message. The first network device 120 may then send 216 a fourth message to the second network device 130 indicating that the compatibility check failed.

[0068] Since the configuration of the potential target cell 104 is incompatible, and the source cell configuration is preserved, the terminal device 110 may quickly fall back to the source cell 102 without having to perform a re-establishment procedure. In some example embodiments, the terminal device 110 resumes 218 data transmission based on the restored source cell configuration.

[0069] Furthermore, in some example embodiments, the terminal device 110 may suspend 220 potential target cells 104 that failed the compatibility check.

[0070] Based on the first message, the network is aware that the reconfiguration for LLM preparation has failed. Therefore, the network can update or remove the target cell configuration that failed the compatibility check. In some embodiments, the second network device 130 can send 222 a fifth message for modifying or releasing at least one target cell configuration.

[0071] After receiving the fifth message, the first network device 120 may send 224 a third message for modifying or releasing at least one target cell configuration. The terminal device 110 may obtain 226 an updated target cell configuration based on the third message. The updated target cell configuration may correspond to at least one updated target cell.

[0072] In some embodiments, the first network device 120 may send 228 a second message for triggering LLM from the source cell 102 to the updated target cell. The second message may be a MAC CE for triggering a target cell handover. Thus, the terminal device 110 may perform an LLM procedure based on the updated target cell configuration.

[0073] Figure 3A A signaling diagram illustrating another example LLM process 301 according to some example embodiments of the present disclosure is shown. The process 301 may involve Figure 1 The terminal device 110, the first network device 120, the second network device 130, and the third network device 122 are shown. For discussion purposes, reference will be made to Figure 1 To describe process 301.

[0074] In process 301, during an LLM process, a compatibility check is performed for at least one target cell configuration of the LLM process. Specifically, the network determines 302 that LLM is to be triggered for the terminal device 110. For example, the determination may be based on L1 measurements from the terminal device 110.

[0075] The terminal device 110 sends 304 a capability indication to restore the source cell configuration based on a compatibility check of the target cell configuration for the LLM procedure.

[0076] After receiving the capability indication, first network device 120 sends 306 the capability indication to second network device 130. In embodiments where LLM is to be triggered, second network device 130 may determine at least one target cell configuration for the LLM procedure based on the capability indication.

[0077] The second network device 130 sends 308 at least one target cell configuration to the first network device 120. The first network device 120 sends 310 at least one target cell configuration to the terminal device 110. In some embodiments, the at least one target cell configuration may be sent in an RRC reconfiguration message. As an example, an example format of the RRC reconfiguration message may be "L1 / L2config, FastRecovery=ALLOWED".

[0078] The terminal device 110 may send 312 an L1 measurement report to the first network device 120. Based on the L1 measurement, the first network device 120 sends 314 a second message for triggering LLM. The second message may be a MAC CE for triggering a target cell handover.

[0079] After receiving the second message, the terminal device 110 performs 316 a compatibility check on at least one target cell configuration based on the configuration state of the terminal device 110. In some example embodiments, the terminal device 110 may apply at least one target cell configuration based on the configuration state of the terminal device 110 while retaining the source cell configuration.

[0080] If the compatibility check fails, the terminal device 110 may resume 318 data transmission based on the source cell configuration. In this way, the terminal device 110 may quickly fall back to the source cell 102 without having to perform a re-establishment procedure.

[0081] Additionally or alternatively, in process 301, the terminal device 110 may send 320 a first message indicating a compatibility check failure to the first network device 120. The first message may be, for example, an L1 report including an indication of a compatibility check failure. The first network device 120 may then send 322 a fourth message indicating a compatibility check failure to the second network device 130. In this case, the UE notifies the DU of a reconfiguration failure for LLM preparation, and then the DU notifies the CU of the reconfiguration failure.

[0082] Alternatively, as another example of process 301, the terminal device 110 may send a first message to the second network device 130, and then the second network device 130 may send a sixth message indicating that the compatibility check failed to the first network device 120. In this case, the UE notifies the CU of the failure of the reconfiguration prepared for the LLM, and then the CU notifies the DU of the reconfiguration failure. Alternatively, the UE may separately notify the CU and the DU of the failure of the reconfiguration prepared for the LLM, which will be combined with Figure 3B Let's discuss.

[0083] Reference Figure 3A , the second network device 130 may send 324 a fifth message for modifying or releasing at least one target cell configuration to the first network device 120. After receiving the fifth message, the first network device 120 may send 326 a third message for modifying or releasing at least one target cell configuration to the terminal device 110, so that the updated target cell configuration is acquired at the terminal device 110. Therefore, the terminal device 110 may perform the LLM process based on the updated target cell configuration.

[0084] Figure 3BA signaling diagram illustrating another example LLM process 302 according to some example embodiments of the present disclosure is shown. The process 302 may involve Figure 1 The terminal device 110, the first network device 120, the second network device 130, and the third network device 122 are shown. For discussion purposes, reference will be made to Figure 1 To describe process 301.

[0085] In process 302, a compatibility check for at least one target cell configuration of the LLM process is performed during the LLM process. Specifically, the network determines 330 that LLM for the terminal device 110 will be triggered.

[0086] The terminal device 110 sends 332 to the second network device 130 a capability indication of restoring the source cell configuration based on a compatibility check of the target cell configuration for the LLM procedure.

[0087] The first network device 120 sends 334 at least one target cell configuration to the terminal device 110. In some embodiments, the at least one target cell configuration may be sent in an RRC reconfiguration message. In response to the RRC reconfiguration message, the terminal device 110 sends 336 an RRC reconfiguration complete message to the first network device 120. After receiving the RRC reconfiguration message, the first network device 120 sends 338 an uplink RRC transfer message to the second network device 130.

[0088] In some example embodiments, the terminal device 110 performs 340 a compatibility check on at least one target cell configuration before sending the L1 report to the first network device 120. Furthermore, the terminal device 110 retains 342 a current configuration state for potential recovery.

[0089] In some example embodiments, the terminal device 110 performs a compatibility check by applying 334 at least one target cell configuration. If the compatibility check fails, the terminal device 110 restores 346 the complete source cell configuration. In this way, data transmission and service is resumed with reduced interruption.

[0090] In some example embodiments, the terminal device 110 sends 348 an L1 report including an indication that the compatibility check failed to the first network device 120. As an example, an example format of the indication may be "Target-cell: Config fail".

[0091] After receiving the L1 report, the first network device 120 stops 350 changing a transmission configuration indication (TCI) state for at least one target cell.

[0092] In some example embodiments, the terminal device 110 sends 352 failure information to the second network device 130, the failure information including an indication of LLM failure and at least one identifier of at least one target cell. For illustrative purposes, an example format of the failure information may be "FailureInfoLLM (configFailure), Config-Id". It should be understood that any other information format and content are also applicable to the implementation of the present disclosure. In this case, the UE notifies the CU and DU of the compatibility check results respectively.

[0093] In some example embodiments, the terminal device 110 receives 354 an RRC reconfiguration message for modifying or releasing at least one target cell configuration from the second network device 130. Accordingly, the terminal device 110 may perform an LLM procedure based on the target cell configuration.

[0094] According to an example embodiment of the present disclosure, a reconfiguration failure handling mechanism is supported for the LLM process. This mechanism enhances the ability of the UE to perform compliance checks on the potential target cell configuration before switching to the target cell. In the case where the potential target cell configuration is not applicable to the configuration state of the UE, the UE can fall back to the source cell configuration and notify the CU and DU of the reconfiguration failure. Therefore, the network can update the target cell configuration without triggering the cell selection process. Therefore, service interruption and signaling overhead are reduced, and system performance is improved.

[0095] Figure 4 4 is a flowchart of an example method 400 according to some example embodiments of the present disclosure. The method 400 may be implemented at a terminal device, for example, referring to Figure 1 For discussion purposes, reference will be made to the terminal device 110. Figure 1 Method 400 is described.

[0096] At 410, the terminal device 110 sends a capability indication of restoring the source cell configuration based on the compatibility check of the target cell configuration for the LLM process to the first network device 120 providing the source cell 102 for the terminal device 110. LLM may include: L1 center mobility or L1 / L2 mobility.

[0097] In some example embodiments, the capability indication (e.g., UE capability indication) may be sent in an RRC message. For example, the RRC message may be a connection establishment complete message. In other words, the capability indication may be sent during the RRC connection establishment process.

[0098] At 420 , the terminal device 110 receives at least one target cell configuration for the LLM process from the first network device 120 . For example, the at least one target cell configuration may correspond to the target cell 104 provided by the third network device 122 .

[0099] In some example embodiments, the at least one target cell configuration may be received in an RRC reconfiguration message from first network device 120. As an example, an example format of the RRC reconfiguration message may be "L1 / L2 config, FastRecovery=ALLOWED".

[0100] At 430 , the terminal device 110 performs a compatibility check on at least one target cell configuration based on the configuration state of the terminal device 110 . The configuration state of the terminal device 110 may include, but is not limited to, a MIMO configuration of the terminal device 110 .

[0101] In some cases, the network may instruct the UE to verify the configuration compatibility of the potential target cell 104 as part of the RRC configuration to activate the pre-check function. Thus, in some embodiments, the terminal device 110 may receive an instruction from one of the first network device 120 and the second network device 130 to verify the compatibility of the target cell configuration for the LLM procedure.

[0102] In some example embodiments, the terminal device 110 may apply at least one target cell configuration based on the configuration state of the terminal device 110 while retaining the source cell configuration.

[0103] At 440, the terminal device 110 determines whether the compatibility check fails. As an example, if at least one target cell configuration is incompatible with the current configuration state, the terminal device 110 may determine that the compatibility check fails. Otherwise, the compatibility check passes.

[0104] If the compatibility check fails, the terminal device 110 resumes data transmission based on the restored source cell configuration at 450. Since the source cell configuration is preserved, the terminal device 110 can fall back to the source cell 102 using the source cell configuration. In addition, the terminal device 110 can suspend the potential target cell 104 that failed the compatibility check. In this way, data transmission can be resumed without performing a reestablishment process, thereby reducing service interruption and signaling overhead.

[0105] In some example embodiments, the terminal device 110 sends a first message indicating a compatibility check failure to at least one of the first network device 120 or the second network device 130 that manages the first network device.

[0106] The terminal device 110 may perform a compatibility check immediately after receiving the configuration of the potential target cell, or alternatively wait until a MAC CE for triggering a target cell handover is received. In some example embodiments, the compatibility check may be performed before sending a layer 1 measurement report for at least one target cell, and the first message may include an RRC reconfiguration complete message.

[0107] In an embodiment in which a compatibility check is performed before the LLM process is triggered by the network, the terminal device 110 may receive a third message from the first network device 120 for modifying or releasing at least one target cell configuration. Therefore, the terminal device 110 may obtain an updated target cell configuration based on the third message. The updated target cell configuration may correspond to a set of updated target cells. Then, the terminal device 110 may wait for a second message from the first network device 120 for switching to one or more updated target cells. The second message may be, for example, a MAC CE for triggering LLM. In response to receiving the second message, the terminal device 110 may perform the LLM process based on the updated target cell configuration.

[0108] Alternatively, the terminal device 110 may not check the configuration compatibility of the potential target cell until the LLM is triggered by the network. In some example embodiments, the terminal device 110 may receive a second message for triggering the LLM from the first network device 120. The terminal device 110 may perform a compatibility check during the LLM process.

[0109] In an embodiment where a compatibility check is performed during the LLM process, the terminal device 110 may send a layer 1 report including an indication of a compatibility check failure to the first network device 120. In addition, the terminal device 110 may send failure information to the second network device 130, the failure information including an indication of an LLM failure and at least one identifier of at least one target cell. For illustrative purposes, an example format of the failure information may be "FailureInfoLLM (configFailure), Config-Id". It should be understood that any other information formats and contents are also applicable to implementations of the present disclosure.

[0110] In the above embodiment, the terminal device 110 may receive an RRC reconfiguration message for releasing or modifying at least one target cell configuration from the second network device 130. Then, the terminal device 110 may wait for a second message from the first network device 120. In response to receiving the second message, the terminal device 110 may perform an LLM process based on the RRC reconfiguration message.

[0111] According to an exemplary embodiment of the present disclosure, the UE is enhanced with the ability to perform compliance checks on potential target cell configurations before switching to the target cell. In this way, the UE is able to verify its suitability for the current state of the device and, potentially, revert to the original configuration as part of this pre-check process. In the case where the UE is configured with multiple target cell configurations for low-layer mobility, this capability can be used to verify configuration compatibility and identify problems in advance so that the re-establishment process can be avoided.

[0112] Figure 5 1 shows a flow chart of an example method 500 according to some example embodiments of the present disclosure. The method 500 may be implemented at a distributed unit (DU), for example, with reference to Figure 1 For discussion purposes, reference will be made to the first network device 120. Figure 1 Method 500 is described.

[0113] At 510, the first network device 120 receives a capability indication to restore the source cell configuration based on the compatibility check of the target cell configuration for the LLM process from the terminal device 110 in the source cell 102 provided by the first network device 120. LLM may include: layer 1 center mobility, or layer 1 / layer 2 mobility.

[0114] In some example embodiments, the capability indication (e.g., UE capability indication) may be received in an RRC message. For example, the RRC message may be a connection setup complete message. In other words, the indication of the recovery capability may be sent during the RRC connection setup process.

[0115] At 520, the first network device 120 sends a capability indication to the second network device 130 that manages the first network device 120. For example, the first network device 120 and the third network device 122 act as DUs, and the second network device 130 acts as a CU.

[0116] In the case of LLM, the handover from the source cell 102 to the target cell 104 is controlled by the network. At 530, the first network device 120 determines whether to trigger LLM. For example, the determination may be based on L1 measurements from the terminal device 110.

[0117] If LLM is to be triggered, then at 540, the first network device 120 sends at least one target cell configuration for the LLM process to the terminal device 110. The at least one target cell configuration may be obtained from the second network device 130. Figure 1 In the example shown, the at least one target cell configuration may correspond to the target cell 104 provided by the third network device 122 .

[0118] In some cases, the network may also instruct the UE to verify the configuration compatibility of the potential target cell 104 as part of the RRC configuration to activate the pre-check function. In some example embodiments, the first network device 120 may send an indication to the terminal device 110 to verify the compatibility of the target cell configuration for the LLM procedure.

[0119] In some example embodiments, the first network device 120 may receive a first message indicating a compatibility check failure for at least one target cell configuration from the terminal device 110. As an example, the compatibility check may fail if the target cell configuration is incompatible with a current configuration state of the terminal device 110 (e.g., the target cell configuration is not applicable to a MIMO configuration).

[0120] In some example embodiments, a first message may be received from the terminal device 110 prior to receiving a layer 1 measurement report for at least one target cell, and the first message may include an RRC reconfiguration complete message. As an example, at least one target cell configuration may be sent in an RRC reconfiguration message, and the first message may include an RRC reconfiguration complete message received from the terminal device 110. As an illustration, an example format of the RRC reconfiguration message may be "L1 / L2 config, FastRecovery=ALLOWED".

[0121] In these embodiments, a compatibility check is performed before the LLM process is triggered by the network. After receiving the first message, the first network device 120 may send a fourth message indicating that the compatibility check failed to the second network device 130. The first network device 120 may receive a fifth message for modifying or releasing at least one target cell configuration from the second network device 130. The first network device 120 may send a third message for modifying or releasing at least one target cell configuration to the terminal device 110, so that the updated target cell configuration is acquired at the terminal device 110. The first network device 120 may send a second message to the terminal device 110, the second message being used to trigger an LLM based on the updated target cell configuration. The second message may be, for example, a MAC CE for switching to the updated target cell.

[0122] In some embodiments, the compatibility check is performed during the LLM process.In these embodiments, the first network device 120 may receive the first message after sending the second message for triggering the LLM, and the first message may include a layer 1 report.

[0123] Additionally or alternatively, in response to the first message, the first network device 120 may send a fourth message indicating a compatibility check failure to the second network device 130. In this case, the UE notifies the DU of a reconfiguration failure for LLM preparation, and then the DU notifies the CU of the reconfiguration failure. The first network device 120 may receive a fifth message for modifying or releasing at least one target cell configuration from the second network device 130. The first network device 120 may send a third message for modifying or releasing at least one target cell configuration to the terminal device 110, so that the updated target cell configuration is acquired at the terminal device 110. The first network device 120 may send a second message to the terminal device 110, the second message being used to trigger an LLM based on the updated target cell configuration.

[0124] Alternatively, in an embodiment in which a compatibility check is performed during the LLM process, the first network device 120 may receive a sixth message indicating a compatibility check failure on at least one target cell configuration from the second network device 130 instead of receiving the first message. In this case, the UE notifies the CU that the reconfiguration prepared for the LLM has failed, and then the CU notifies the DU of the reconfiguration failure. In addition, the first network device 120 may receive a fifth message for releasing or modifying at least one target cell configuration from the second network device 130. The first network device 120 may send a third message for modifying or releasing at least one target cell configuration to the terminal device 110, so that the updated target cell configuration is acquired at the terminal device 110.

[0125] Alternatively, in an embodiment in which a compatibility check is performed during the LLM process, in response to a layer 1 report including an indication of a compatibility check failure, the first network device 120 may stop changing the TCI state of at least one target cell 104. In addition, the terminal device 110 may send failure information to the second network device 130, the failure information including an indication of the LLM failure and at least one identifier of the at least one target cell. In this case, the UE may notify the CU and DU, respectively, of the failure of the reconfiguration prepared for the LLM. In addition, the second network device 130 may then send an RRC reconfiguration message to the terminal device 110 for modifying or releasing the configuration of at least one target cell.

[0126] According to an example embodiment, a pre-check of the configuration compatibility of at least one potential target cell is supported for the LLM process. The UE can apply the target cell configuration before switching from the source cell to the target cell while retaining the source cell configuration. In the event of a reconfiguration failure, the UE can fall back to the source cell and resume service without performing a reestablishment process. In this way, the service interruption time can be reduced. In addition, the overall robustness and performance of the communication system can be improved.

[0127] Figure 6 600 according to some example embodiments of the present disclosure. The method 600 may be implemented at a centralized unit (CU), for example, Figure 1 For discussion purposes, reference will be made to the second network device 130. Figure 1 Method 600 is described.

[0128] At 610, second network device 130 receives a capability indication of restoring the source cell based on a compatibility check of the target cell configuration for the LLM procedure from one of first network device 120 or terminal device 110. First network device 120 is managed by second network device 130 and provides source cell 102 for terminal device 110.

[0129] In some example embodiments, LLM may include: layer 1 centric mobility, or layer 1 / layer 2 mobility.

[0130] In some example embodiments, the indication of the recovery capability may be received during the RRC connection establishment process. For example, the indication of the recovery capability may be received in an RRC connection establishment complete message.

[0131] At 620, the second network device 130 determines whether to trigger LLM for the terminal device 110. In the case of LLM, the handover from the source cell 102 to the target cell 104 is controlled by the network. For example, the determination may be based on L1 measurements from the terminal device 110.

[0132] If LLM is to be triggered, then at 630, the second network device 130 determines at least one target cell configuration for the LLM process based on the capability indication. For example, the at least one target cell configuration may correspond to the target cell 104 provided by the third network device 122. Figure 1 In the example shown, the first network device 120 and the third network device 122 act as DUs, and the second network device 130 acts as a CU.

[0133] At 640 , second network device 130 sends at least one target cell configuration to first network device 120 .

[0134] In some example embodiments, the second network device 130 may send an indication to one of the first network device 120 or the terminal device 110 for verifying the compatibility of the target cell configuration for the LLM procedure.

[0135] The compatibility check may be performed immediately after receiving the configuration of the potential target cell, or may not be performed until the LLM is triggered. In an embodiment where the compatibility check is performed before the LLM is triggered, the second network device 130 may receive a fourth message indicating a compatibility check failure from the first network device 120. In response to receiving the fourth message, the second network device 130 may send a fifth message to the first network device 120 for modifying or releasing at least one target cell configuration.

[0136] In an embodiment in which a compatibility check is performed during the LLM process, the second network device 130 may receive failure information from the terminal device 110, the failure information including an indication of the LLM failure and at least one identifier of at least one target cell. For illustrative purposes, an example format of the failure information may be "FailureInfoLLM (configFailure), Config-Id". It should be understood that any other information format and content are also applicable to the implementation of the present disclosure.

[0137] In addition, in response to receiving the failure information, the second network device 130 may send an RRC reconfiguration message for modifying or releasing at least one target cell configuration to the terminal device 110. In some example embodiments, the second network device 130 may send a sixth message indicating the compatibility check failure to the first network device 120. In this case, the UE notifies the CU of the failure of the reconfiguration prepared for the LLM, and then the CU notifies the DU of the reconfiguration failure.

[0138] Alternatively, in an embodiment in which a compatibility check is performed during the LLM process, the second network device 130 may receive a fourth message indicating a compatibility check failure from the first network device 120. In this case, the UE notifies the DU of a reconfiguration failure for LLM preparation, and then the DU notifies the CU of the reconfiguration failure. In response to receiving the fourth message, the second network device 130 may send a fifth message to the first network device 120 for modifying or releasing at least one target cell configuration.

[0139] According to an example embodiment of the present disclosure, a reconfiguration failure handling mechanism is supported for the LLM process. This mechanism enhances the ability of the UE to perform compliance checks on the potential target cell configuration before switching to the target cell. In the case where the potential target cell configuration is not applicable to the configuration state of the UE, the UE can fall back to the source cell configuration and notify the CU and DU of the reconfiguration failure. Therefore, the network can update the target cell configuration without triggering the cell selection process. Therefore, service interruption and signaling overhead are reduced, and system performance is improved.

[0140] In some example embodiments, the first device (e.g., terminal device 110) capable of executing method 400 may include: a component for executing each step of method 400. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit system or a software module. In some embodiments, the component may include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to cause the execution of the first device together with the at least one processor.

[0141] In some example embodiments, a first device includes: a component for sending a capability indication for recovering a source cell configuration based on a compatibility check of a target cell configuration for a low-layer mobility (LLM) process to a second device that provides a source cell for the first device; a component for receiving at least one target cell configuration for the LLM process from the second device; a component for performing a compatibility check on at least one target cell configuration based on a configuration state of the first device; and a component for recovering data transmission based on a recovered source cell configuration in accordance with a determination of a compatibility check failure.

[0142] In some example embodiments, the capability indication is sent in a Radio Resource Control, RRC, message.

[0143] In some example embodiments, the first apparatus further comprises means for receiving an indication to verify compatibility of the target cell configuration for the LLM procedure from one of the second apparatus or a third apparatus that manages the second apparatus.

[0144] In some example embodiments, the first device further includes means for sending a first message indicating a compatibility check failure to at least one of the second device or a third device that manages the second device.

[0145] In some example embodiments, prior to sending the layer 1 measurement report for the at least one target cell, a compatibility check is performed and the first message comprises a Radio Resource Control, RRC Reconfiguration Complete message.

[0146] In some example embodiments, the first device further includes: a component for receiving a third message from the second device for modifying or releasing at least one target cell configuration; a component for acquiring an updated target cell configuration based on the third message; and a component for performing an LLM process based on the updated target cell configuration in response to receiving the second message.

[0147] In some example embodiments, means for performing the compatibility check includes means for receiving a second message for triggering the LLM from the second device; and means for performing the compatibility check during the LLM process.

[0148] In some example embodiments, means for sending the first message comprises means for sending a layer 1 report including an indication that the compatibility check failed to the second apparatus.

[0149] In some example embodiments, the means for sending the first message includes means for sending failure information to the third apparatus, the failure information including an indication of LLM failure and at least one identification of at least one target cell.

[0150] In some example embodiments, the first device further comprises means for: receiving a radio resource control, RRC, reconfiguration message for releasing or modifying at least one target cell configuration from a third device; and in response to receiving the second message, performing an LLM process based on the RRC reconfiguration message.

[0151] In some example embodiments, the means for performing the compatibility check includes means for applying at least one target cell configuration while retaining the source cell configuration based on a configuration state of the first apparatus.

[0152] In some example embodiments, the LLM includes layer 1 centric mobility.

[0153] In some example embodiments, the second device (e.g., the first network device 120) capable of performing the method 500 may include a component for performing the various steps of the method 500. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit system or a software module. In some embodiments, the component may include at least one processor and at least one memory including a computer program code. The at least one memory and the computer program code are configured to, together with the at least one processor, cause the execution of the second device.

[0154] In some example embodiments, the second device includes: a component for receiving a capability indication for recovering a source cell configuration based on a compatibility check of a target cell configuration for a low-layer mobility LLM process from a first device, the first device being in a source cell provided by the second device; a component for sending the capability indication to a third device that manages the second device; and a component for sending at least one target cell configuration for the LLM process to the first device based on a determination that the LLM will be triggered for the first device, the at least one target cell configuration being obtained from the third device.

[0155] In some example embodiments, the capability indication is received in a Radio Resource Control, RRC, message.

[0156] In some example embodiments, the second apparatus further comprises means for sending an indication to the first apparatus to verify compatibility of the target cell configuration for the LLM procedure.

[0157] In some example embodiments, the second apparatus further comprises means for receiving a first message from the first apparatus indicating that a compatibility check of at least one target cell configuration has failed.

[0158] In some example embodiments, prior to receiving the layer 1 measurement report for the at least one target cell, a first message is received from the first device, and the first message comprises an RRC reconfiguration complete message.

[0159] In some example embodiments, the second device receives the first message after sending the second message for triggering the LLM, and the first message includes a layer 1 report.

[0160] In some example embodiments, the second device further includes: a component for sending a fourth message indicating a compatibility check failure to a third device in response to receiving the first message; a component for receiving a fifth message for modifying or releasing at least one target cell configuration from the third device; a component for sending a third message for modifying or releasing at least one target cell configuration to the first device, so that the updated target cell configuration is acquired at the first device; and a component for sending a second message to the first device for triggering an LLM based on the updated target cell configuration.

[0161] In some example embodiments, the second apparatus further comprises means for stopping changing a transmission configuration indication (TCI) state for at least one target cell in response to a layer 1 report comprising an indication of a compatibility check failure.

[0162] In some example embodiments, a third device (e.g., second network device 130) capable of executing method 600 may include a component for executing the various steps of method 600. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit system or a software module. In some embodiments, the component may include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to cause the execution of the third device together with the at least one processor.

[0163] In some example embodiments, the third device includes: a component for receiving a capability indication of recovering a source cell based on a compatibility check of a target cell configuration for a low-layer mobility LLM process from one of the first device or the second device, the second device being managed by the third device and providing the source cell for the first device; a component for determining at least one target cell configuration for the LLM process based on the capability indication according to a determination that the LLM will be triggered for the first device; and a component for sending the at least one target cell configuration to the second device.

[0164] In some example embodiments, the capability indication is received in a Radio Resource Control, RRC, message.

[0165] In some example embodiments, the third apparatus further comprises means for sending an indication to one of the second apparatus or the first apparatus for verifying compatibility of the target cell configuration for the LLM procedure.

[0166] In some example embodiments, the third device further includes: a component for receiving failure information from the first device before triggering the LLM, the failure information including an indication of the LLM failure and at least one identifier of at least one target cell; and a component for sending a radio resource control RRC reconfiguration message to the first device for modifying or releasing the configuration of at least one target cell in response to receiving the failure information.

[0167] In some example embodiments, the third apparatus further comprises: means for receiving a first message indicating a compatibility check failure from the first apparatus; and means for sending a sixth message indicating a compatibility check failure to the second apparatus in response to the first message.

[0168] In some example embodiments, the first message is received before the LLM is triggered.

[0169] In some example embodiments, the first message is received during a LLM process.

[0170] In some example embodiments, the third apparatus further comprises means for receiving a fourth message from the second apparatus indicating that the compatibility check has failed.

[0171] In some example embodiments, the third apparatus further comprises means for sending a fifth message for modifying or releasing at least one target cell configuration to the second apparatus.

[0172] In some example embodiments, the fourth message is received before the LLM process is triggered.

[0173] In some example embodiments, the fourth message is received during the LLM process.

[0174] Figure 7 is a simplified block diagram of a device 700 suitable for implementing embodiments of the present disclosure. The device 700 may be provided to implement a communication device, such as Figure 1 The terminal device 110, the first network device 120, and the second network device 130 are shown. As shown in the figure, the device 700 includes one or more processors 710, one or more memories 740 coupled to the processor 710, and one or more transmitters and / or receivers (TX / RX) 740 coupled to the processor 710.

[0175] TX / RX 740 is used for bidirectional communication. TX / RX 740 has at least one antenna to facilitate communication. The communication interface may represent any interface required for communicating with other network elements.

[0176] Processor 710 may be of any type suitable for the local technology network, and may include, as non-limiting examples, one or more of: a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. Device 700 may have multiple processors, such as application specific integrated circuit chips, which are time-slaved to a clock synchronized with a main processor.

[0177] The memory 720 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read-only memory (ROM) 724, electrically programmable read-only memory (EPROM), flash memory, hard disk, compact disk (CD), digital video disk (DVD), and other magnetic storage devices and / or optical storage devices. Examples of volatile memories include, but are not limited to, random access memory (RAM) 722, and other volatile memories that do not persist during power outages.

[0178] The computer program 730 includes computer executable instructions that are executed by the associated processor 710. The program 730 may be stored in the ROM 724. The processor 710 may perform any suitable actions and processes by loading the program 730 into the RAM 722.

[0179] The embodiments of the present disclosure may be implemented by a program 730, so that the device 700 may execute the Figures 4 to 6 Any process of the present disclosure discussed. The embodiments of the present disclosure may also be implemented by hardware, or by a combination of software and hardware.

[0180] In some embodiments, the program 730 may be tangibly embodied in a computer-readable medium that may be included in the device 700 (e.g., in the memory 720) or in other storage devices accessible by the device 700. The device 700 may load the program 730 from the computer-readable medium to the RAM 722 for execution. The computer-readable medium may include any type of tangible non-volatile memory, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc. Figure 8 An example of a computer readable medium 800 in the form of a CD or DVD is shown. The computer readable medium has a program 730 stored thereon.

[0181] Generally, various embodiments of the present disclosure may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of the present disclosure are illustrated and described as block diagrams, flow charts, or using some other graphical representations, it should be understood that, as non-limiting examples, the boxes, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general hardware or controllers or other computing devices, or some combination thereof.

[0182] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer executable instructions, such as instructions included in a program module, which are executed in a device on a target physical or virtual processor to perform the above referenced Figures 4 to 5 Method 400, 500 or 600 described herein. Typically, a program module includes a routine, program, library, object, class, component, data structure, etc. that performs a specific task or implements a specific abstract data type. In various embodiments, the functions of the program modules can be combined or split between program modules as needed. Machine executable instructions for program modules can be executed in local or distributed devices. In distributed devices, program modules can be located in both local and remote storage media.

[0183] The program code for executing the method of the present disclosure can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer or other programmable data processing device so that the program code, when executed by the processor or controller, enables the function / operation specified in the flow chart and / or block diagram to be realized. The program code can be executed completely on the machine, partially on the machine, as an independent software package, partially on the machine and partially on a remote machine, or completely on a remote machine or server.

[0184] In the context of the present disclosure, computer program codes or related data may be carried by any suitable carrier to enable a device, apparatus or processor to perform various processes and operations as described above. Examples of carriers include signals, computer readable media, etc.

[0185] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. The computer readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or means, or any suitable combination of the foregoing. More specific examples of computer readable storage media would include: an electrical connection with one or more wires, a portable computer floppy disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0186] In addition, although the operations are described in a particular order, this should not be understood as requiring such operations to be performed in the particular order shown or in order, or performing all the operations shown, to obtain the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details are included in the above discussion, these should not be interpreted as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to a particular embodiment. Certain features described in the context of a separate embodiment may also be implemented in combination in a single embodiment. On the contrary, the various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable sub-combination.

[0187] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it should be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Instead, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A terminal device, comprising: at least one processor; as well as at least one memory including computer program code; The at least one memory and the computer program code are configured to, together with the at least one processor, cause the terminal device to at least: Sending, to a first network device providing a source cell for the terminal device, a capability indication for restoring a source cell configuration based on a compatibility check of a target cell configuration for a low layer mobility LLM procedure; receiving at least one target cell configuration for the LLM process from the first network device; Based on the configuration state of the terminal device, perform the compatibility check on the at least one target cell configuration; as well as Based on the determination that the compatibility check has failed, data transmission is resumed based on the restored configuration of the source cell.

2. The terminal device according to claim 1, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, further cause the terminal device to: An indication is received from one of the first network device and the second network device to verify compatibility of a target cell configuration for the LLM procedure.

3. The terminal device according to claim 1, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, further cause the terminal device to at least: A first message indicating that the compatibility check has failed is sent to at least one of the first network device or a second network device that manages the first network device.

4. The terminal device according to claim 3, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, further cause the terminal device to: receiving, from the first network device, a third message for modifying or releasing the at least one target cell configuration; Based on the third message, acquiring an updated target cell configuration; and In response to receiving a second message for triggering the LLM, the LLM process is performed based on the updated target cell configuration.

5. The terminal device according to claim 3, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, enable the terminal device to perform the compatibility check by: receiving a second message for triggering the LLM from the first network device; and The compatibility check is performed during the LLM process.

6. The terminal device according to claim 5, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the terminal device to send the first message by: A layer 1 report is sent to the first network device, the layer 1 report including an indication that the compatibility check failed.

7. The terminal device according to claim 5, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the terminal device to send the first message by: Sending failure information to the second network device, the failure information including: An indication of the LLM failure, and at least one identification of the at least one target cell.

8. A first network device, comprising: at least one processor; as well as at least one memory including computer program code; The at least one memory and the computer program code are configured to, together with the at least one processor, cause the first network device to at least: receiving, from a terminal device, a capability indication for restoring a source cell configuration based on a compatibility check of a target cell configuration for a low layer mobility (LLM) procedure, the terminal device being in a source cell provided by the first network device; Sending the capability indication to a second network device that manages the first network device; as well as Based on the determination that the LLM is to be triggered, at least one target cell configuration for the LLM process is sent to the terminal device, the at least one target cell configuration being acquired from the second network device.

9. The first network device of claim 8, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, further cause the first network device to: An indication is sent to the terminal device to verify the compatibility of the target cell configuration for the LLM process.

10. The first network device of claim 8, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, further cause the first network device to: A first message is received from the terminal device, the first message indicating that a compatibility check of the at least one target cell configuration has failed.

11. The first network device according to claim 10, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, further cause the first network device to: In response to receiving the first message, sending a fourth message to the second network device indicating that the compatibility check failed; receiving, from the second network device, a fifth message for modifying or releasing the at least one target cell configuration; Sending a third message for modifying or releasing the at least one target cell configuration to the terminal device, so that the updated target cell configuration is acquired at the terminal device; as well as A second message is sent to the terminal device, where the second message is used to trigger the LLM based on the updated target cell configuration.

12. A second network device, comprising: at least one processor; as well as at least one memory including computer program code; The at least one memory and the computer program code are configured to, together with the at least one processor, cause the second network device to at least: receiving, from one of a first network device or a terminal device, a capability indication of restoring a source cell based on a compatibility check of a target cell configuration for a low layer mobility (LLM) procedure, the first network device being managed by the second network device and providing the source cell for the terminal device; in accordance with a determination that the LLM is to be triggered for the terminal device, determining at least one target cell configuration for the LLM procedure based on the capability indication; as well as The at least one target cell configuration is sent to the first network device.

13. The second network device according to claim 12, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, further cause the second network device to: An indication is sent to one of the first network device or the terminal device for verifying compatibility of a target cell configuration for the LLM procedure.

14. The second network device of claim 12, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, further cause the second network device to: Receive failure information from the terminal device, the failure information comprising: an indication of the LLM failure, and at least one identification of the at least one target cell; as well as In response to receiving the failure information, a radio resource control RRC reconfiguration message for modifying or releasing the at least one target cell configuration is sent to the terminal device.

15. The second network device of claim 14, wherein the failure information is received during the LLM process.

16. The second network device of claim 14, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, further cause the second network device to: In response to receiving the failure information, a sixth message indicating that the compatibility check has failed is sent to the first network device.

17. The second network device of claim 12, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, further cause the second network device to: A fourth message is received from the first network device indicating that the compatibility check failed.

18. A method comprising: At the terminal device, sending a capability indication for restoring the source cell configuration based on a compatibility check of the target cell configuration for the low layer mobility LLM procedure to a first network device providing the source cell for the terminal device; receiving at least one target cell configuration for the LLM process from the first network device; Based on the configuration state of the terminal device, perform the compatibility check on the at least one target cell configuration; as well as Based on the determination that the compatibility check has failed, data transmission is resumed based on the restored configuration of the source cell.

19. A method comprising: At a first network device, receiving a capability indication for restoring a source cell configuration based on a compatibility check of a target cell configuration for a low layer mobility (LLM) procedure from a terminal device, the terminal device being in a source cell provided by the first network device; Sending the capability indication to a second network device that manages the first network device; as well as Based on the determination that the LLM is to be triggered for the terminal device, at least one target cell configuration for the LLM process is sent to the terminal device, the at least one target cell configuration being obtained from the second network device.

20. A method comprising: At the second network device, receiving a capability indication of restoring a source cell based on a compatibility check of a target cell configuration for a low layer mobility (LLM) procedure from one of a first network device or a terminal device, the first network device being managed by the second network device and providing a source cell for the terminal device; in accordance with a determination that the LLM is to be triggered for the terminal device, determining at least one target cell configuration for the LLM procedure based on the capability indication; as well as The at least one target cell configuration is sent to the first network device.

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