Inter-node ltm

Abstract

Embodiments of the present disclosure relate to inter-node LTM In an aspect, a terminal device receives, from a first network device, a LTM configuration for one or more candidate cells of candidate network devices. The LTM configuration comprises an indication indicating an association between L1 measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device and a second network device. The terminal device determines, an L1 measurement configuration for a candidate cell among the one or more candidate cells based on the indication and the LTM configuration. The terminal device performs L1 measurement for the candidate cell based on the L1 measurement configuration. In this way, the configuration for inter-node LTM is provided, and the measurement can be performed based on the configuration for inter-node LTM, thereby improving communication performance related to inter-node LTM.

Description

INTER NODE LTMFIELD

[0001] Various example embodiments relate to the field of communication and in particular, to methods, devices, apparatuses and a computer readable storage medium for inter-node Layer 1 / Lay er2 Triggered Mobility LTM.BACKGROUND

[0002] A communication network can be seen as a facility that enables communications between two or more communication devices, or provides communication devices access to a data network. A mobile or wireless communication network is one example of a communication network.

[0003] Such communication networks operate in accordance with standards, such as those promulgated by 3GPP (Third Generation Partnership Project) or ETSI (European Telecommunications Standards Institute). Examples of such standards include the so-called 5G (5th Generation) standard or other standards promulgated by 3GPP.SUMMARY

[0004] In general, example embodiments of the present disclosure provide a solution for inter-node LTM. With this solution, the configuration for inter-node LTM is provided, and the measurement can be performed based on the configuration for inter-node LTM, thereby improving communication performance related to inter-node LTM.

[0005] In a first aspect, there is provided a terminal device. The terminal device comprises at least one processor and at least one memory storing instructions. The instructions, when executed by the at least one processor, cause the terminal device at least to receive, from a first network device, a LTM configuration for one or more candidate cells of candidate network devices. The LTM configuration comprises an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device and a second network device. The terminal device is further caused to determine, an LI measurement configuration for a candidate cell among the one or more candidate cells based on the indication and the LTM configuration. The terminal device is further caused to perform,LI measurement for the candidate cell based on the LI measurement configuration.

[0006] In a second aspect, there is provided a first network device. The first network device comprises at least one processor and at least one memory storing instructions. The instructions, when executed by the at least one processor, cause the first network device at least to transmit, to a second network device, a handover request for LTM. The first network device is further caused to receive, from the second network device, a handover response for the LTM. The handover response comprises a first LTM configuration for one or more candidate cells of candidate network devices. The first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device and the second network device. The first network device is further caused to transmit, to a terminal device, a second LTM configuration for candidate cells of the candidate network devices. The second LTM configuration comprises an indication indicating the association between the LI measurement configuration for the candidate cells and the candidate network devices.

[0007] In a third aspect, there is provided a second network device. The second network device comprises at least one processor and at least one memory storing instructions. The instructions, when executed by the at least one processor, cause the second network device at least to receive, from a first network device, a handover request for LTM. In addition, the second network device is further caused to transmit, to the first network device, a handover response for the LTM. The handover response comprises a first LTM configuration for one or more candidate cells of candidate network device. The first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating the association between the LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device and the second network device.

[0008] In a fourth aspect, there is provided a method implemented at a terminal device. The method comprises receiving, from a first network device, a LTM configuration for one or more candidate cells of candidate network devices. The LTM configuration comprises an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device and a second network device. The method furthercomprises determining, an LI measurement configuration for a candidate cell among the one or more candidate cells based on the indication and the LTM configuration. The method further comprises performing, LI measurement for the candidate cell based on the LI measurement configuration.

[0009] In a fifth aspect, there is provided a method implemented at a first network device. The method comprises transmitting, to a second network device, a handover request for LTM. The method further comprises receiving, from the second network device, a handover response for the LTM. The handover response comprises a first LTM configuration for one or more candidate cells of candidate network devices. The first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices, and the candidate network devices comprise the first network device and the second network device. The method further comprises transmitting, to a terminal device, a second LTM configuration for candidate cells of the candidate network devices. The second LTM configuration comprises an indication indicating the association between the LI measurement configuration for the candidate cells and the candidate network devices.

[0010] In a sixth aspect, there is provided a method implemented at a second network device. The method comprises receiving, from a first network device, a handover request for LTM. The method further comprises transmitting, to the first network device, a handover response for the LTM. The handover response comprises a first LTM configuration for one or more candidate cells of candidate network device. The first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating the association between the LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device and the second network device.

[0011] In a seventh aspect, there is provided an apparatus. The apparatus comprises means for receiving, from a first network device, a LTM configuration for one or more candidate cells of candidate network devices. The LTM configuration comprises an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device and a second network device. The apparatus further comprises means for determining, an LI measurement configuration for a candidate cell among the one ormore candidate cells based on the indication and the LTM configuration. The apparatus further comprises means for performing, LI measurement for the candidate cell based on the LI measurement configuration.

[0012] In an eighth aspect, there is provided an apparatus. The apparatus comprises means for transmitting, to a second network device, a handover request for LTM. The apparatus further comprises means for receiving, from the second network device, a handover response for the LTM. The handover response comprises a first LTM configuration for one or more candidate cells of candidate network devices. The first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device and the second network device. The apparatus further comprises means for transmitting, to a terminal device, a second LTM configuration for candidate cells of the candidate network devices. The second LTM configuration comprises an indication indicating the association between the LI measurement configuration for the candidate cells and the candidate network devices.

[0013] In a ninth aspect, there is provided an apparatus. The apparatus comprises means for receiving, from a first network device, a handover request for LTM. The apparatus further comprises means for transmitting, to the first network device, a handover response for the LTM. The handover response comprises a first LTM configuration for one or more candidate cells of candidate network device. The first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating the association between the LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device and the second network device.

[0014] In a tenth aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to any one of the above fourth to sixth aspects.

[0015] In an eleventh aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus to perform at least the method according to any one of the above fourth to sixth aspects.

[0016] In a twelfth aspect, there is provided a terminal device. The terminal devicecomprises receiving circuitry configured to receive, from a first network device, a LTM configuration for one or more candidate cells of candidate network devices. The LTM configuration comprises an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device and a second network device. The terminal device further comprises determining circuitry configured to determine an LI measurement configuration for a candidate cell among the one or more candidate cells based on the indication and the LTM configuration. The terminal device further comprises performing circuitry configured to perform, LI measurement for the candidate cell based on the LI measurement configuration.

[0017] In a thirteenth aspect, there is provided a first network device. The first network device comprises first transmitting circuitry configured to transmit, to a second network device, a handover request for LTM. The first network device further comprises receiving circuitry configured to receive, from the second network device, a handover response for the LTM. The handover response comprises a first LTM configuration for one or more candidate cells of candidate network devices. The first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device and the second network device. The first network device further comprises second transmitting circuitry configured to transmit, to a terminal device, a second LTM configuration for candidate cells of the candidate network devices. The second LTM configuration comprises an indication indicating the association between the LI measurement configuration for the candidate cells and the candidate network devices.

[0018] In a fourteenth aspect, there is provided a second network device. The second network device comprises receiving circuitry configured to receive, from a first network device, a handover request for LTM. In addition, the second network device further comprises transmitting circuitry configured to transmit, to the first network device, a handover response for the LTM. The handover response comprises a first LTM configuration for one or more candidate cells of candidate network device. The first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating the association between the LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the firstnetwork device and the second network device.

[0019] It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0021] FIG. 1 illustrates an example communication network in which embodiments of the present disclosure may be implemented;

[0022] FIG. 2 illustrates a flowchart illustrating an example of process for inter-node LTM according to some embodiments of the present disclosure;

[0023] FIG. 3 A illustrates a flowchart illustrating another example of process for inter-node LTM according to some embodiments of the present disclosure;

[0024] FIG. 3B illustrates an example of RRC structure for inter-node LTM according to some embodiments of the present disclosure;

[0025] FIG. 4 A illustrates a flowchart illustrating another example of process for inter-node LTM according to some embodiments of the present disclosure;

[0026] FIG. 4B illustrates an example of determining the second LTM configuration based on the first LTM configuration according to some embodiments of the present disclosure;

[0027] FIG. 4C illustrates another example of RRC structure for inter-node LTM according to some embodiments of the present disclosure;

[0028] FIG. 5 illustrates an example of overall solutions for inter-node LTM according to some embodiments of the present disclosure;

[0029] FIG. 6 illustrates a flowchart of a method implemented at a terminal device according to some embodiments of the present disclosure;

[0030] FIG. 7 illustrates a flowchart of a method implemented at a first network device according to some other embodiments of the present disclosure;

[0031] FIG. 8 illustrates a flowchart of a method implemented at a second network deviceaccording to some other embodiments of the present disclosure;

[0032] FIG. 9 illustrates a simplified block diagram of an apparatus that is suitable for implementing embodiments of the present disclosure; and

[0033] FIG. 10 illustrates a block diagram of an example computer readable medium in accordance with some embodiments of the present disclosure.

[0034] Throughout the drawings, the same or similar reference numerals represent the same or similar element.DETAILED DESCRIPTION

[0035] Principles of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

[0036] 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 skills in the art to which this disclosure belongs.

[0037] References in the present disclosure to “one embodiment,” “an embodiment,” “an example embodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0038] It shall 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 one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.

[0039] The terminology used herein is for describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “has”, “having”, “includes” and / or “including”, when used herein, specify the presence of stated features, elements, and / or components etc., but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof. As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0040] As used in this application, the term “circuitry” may refer to one or more or all of the following:(a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and(b) combinations of hardware circuits and software, such as (as applicable):(i) a combination of analog and / or digital hardware circuit(s) with software / firmware and(ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and(c) hardware circuit(s) and or processor(s), such as a microprocessor s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0041] This definition of circuitry applies to all uses of this 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 merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0042] As used herein, the term “communication network” refers to a network following any suitable communication standards, such as Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed Packet Access (HSPA), Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the future fifth generation (5G) communication protocols, and / or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

[0043] As used herein, the term “network device” and “access network device” refer to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a NR NB (also referred to as a gNB), a Remote Radio Unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology. The gNB may be further comprises the centralized unit CU and distributed unit DU.

[0044] The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, 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 not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things(loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. In the following description, the terms “terminal device”, “communication device”, “terminal”, “user equipment” and “UE” may be used interchangeably.

[0045] LTM is a cell switch procedure, where user equipment’s serving cell (primary cell PCell or primary secondary cell PSCell) is switched by the network by sending an LTM cell switch command. An LTM switch command is currently delivered by medium access control MAC signaling using a MAC control element CE. Hence, not using radio resource control RRC signaling as a L3 based handover which is one of the current methods for changing between cells. LTM cell switch decision is based on LI measurements that are performed and reported using LI measurement reports by the UE. Measurements and reporting are based on LTM candidate cell configuration provided by the network for one or more LTM candidate cells. An LTM candidate cell may be neighboring cells or a UE’s current serving secondary cells (e.g. SCells).

[0046] In third generation partnership project 3 GPP release- 18, LTM measurements on a neighboring candidate cell are performed using synchronization signal blocks SSBs transmitted by the candidate cell for which the SSB configuration is provided to the UE. Before the cell switch, network may optionally activate one or more transmission configuration indicator TCI state(s) for one or more candidate cells. Once a candidate cell TCI state is activated the UE may start tracking the time / frequency synchronization using the reference signals associated with the activated TCI state(s). The UE may also perform early UL synchronization before the cell switch if this is requested by the network.

[0047] In Rel-18, the decision on list of candidate cells and the preparation of LTM CSI Resource Configuration containing the resource set for LTM measurements on candidate cells are both decided by the serving CU. This is further provided to all the DUs (serving and candidate DUs). DU generate LTM Report-config mapping to the re source- sets.

[0048] Further, LTM needs to be supported for Inter-gNB (or inter-CU) scenarios where the UE may have candidate cells (DUs) belonging to different candidate CUs. Subsequent cell switch execution conditions and candidate cells for execution are typically determined by thesource CU. Therefore, in case of inter-CU scenarios, the decision on list of candidate cells and its reference signals (e.g., beams) to be used for LTM measurements and report should be decided separately by each CU.

[0049] In other words, it is expected that each candidate CU (and the serving CU) would determine the LTM resource sets (each resource set containing the SSBs indices from one or more candidate cells) applicable for all of its DUs for LTM measurement and reporting. Therefore, the LTM resource sets that were prepared by a one CU (serving CU) for all its DUs will not be applicable for the DUs belonging to other CUs.

[0050] For seamless subsequent cell switches, coordination and consolidation of resourcesets across gNBs are needed. Signalling efficient mean to communicate the combined resource sets for all candidates is preferred. Additionally, in case of different sets of resource sets for each CU, mechanisms for the UE to indicate which resource sets to be referred are needed.

[0051] According to some embodiments of the present disclosure, there is provided a solution for determining the configuration for inter-node LTM. Principles and embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0052] FIG. 1 illustrates a schematic diagram of an example communication network 100 in which some embodiments of the present disclosure can be implemented. As shown in FIG. 1, the communication network 100 may include terminal device 110, a first network device 121, and a second network device 122.

[0053] It is to be understood that the number of network devices and terminal devices is only for the purpose of illustration without suggesting any limitations. The system 100 may include any suitable number of network devices and terminal devices adapted for implementing embodiments of the present disclosure.

[0054] Communications in the communication system 100 may be implemented according to any proper communication protocol(s), comprising, but not limited to, cellular communication protocols of the first generation (1G), the second generation (2G), the third generation (3G), the fourth generation (4G) and the fifth generation (5G) and on the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any properwireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and / or any other technologies currently known or to be developed in the future.

[0055] FIG. 2 illustrates a flowchart illustrating an example of process for inter-node LTM according to some embodiments of the present disclosure. For the purpose of discussion, the process 200 will be described with reference to FIG. 1. The process 200 may involve the terminal device 110, the first network device 121 and the second network device 122 as illustrated in FIG. 1. It would be appreciated that although the process 200 for link has been described in the communication system 100 of FIG. 1, this process may be likewise applied to other communication scenarios where different network devices are jointly deployed to provide respective serving cells.

[0056] In some embodiments, as shown in FIG. 2, the first network device 121 transmits 201 to the second network device 122 a handover request 202 for LTM. The first network device 121 then receives 206 from the second network device 122 a handover response 205 for the LTM. The handover response 205 comprises a first LTM configuration for one or more candidate cells of candidate network devices. The first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device 121 and the second network device 122.

[0057] In some embodiments, the first network device 121 transmits 207 to the terminal device 110 a second LTM configuration for candidate cells of the candidate network devices. The second LTM configuration comprises an indication which can indicate the association between the LI measurement configuration for the candidate cells and the candidate network devices.

[0058] In some embodiments, the terminal device 110 receives 209 from the first network device 121 the LTM configuration 208 for one or more candidate cells of candidate network devices. The LTM configuration comprises an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate networkdevices. The candidate network devices comprise the first network device 121 and a second network device 122. The terminal device 110 determines 210 an LI measurement configuration for a candidate cell among the one or more candidate cells based on the indication and the LTM configuration. The terminal device 110 performs 211 LI measurement for the candidate cell based on the LI measurement configuration.

[0059] With the solution of the process, the LI -measurement configuration preparation across nodes can be realized. In addition, the inter-node coordination and creation of multiple instances of LI -measurement objects based on the coordination towards the terminal device 110 is achieved.

[0060] FIG. 3 A illustrates a flowchart illustrating another example of process for inter-node LTM according to some embodiments of the present disclosure. In FIG. 3 A, there is detailed signaling workflow to support above-mentioned solution. For the purpose of discussion, the process 300 will be described with reference to FIG. 1. The process 300 may involve the terminal device 110, the first network device 121 and the second network device 122 as illustrated in FIG. 1. It would be appreciated that although the process 300 has been described in the communication system 100 of FIG. 1, this process may be likewise applied to other communication scenarios where different network devices are jointly deployed to provide respective serving cells.

[0061] In some embodiments, as shown in FIG. 3A, the first network device 121 comprises a source CU 382 and a source DU 381 for the LTM, and the second network device 122 comprises a target CU 383 and a target DU 384 for the LTM. In addition, the number of CU and DU is just example, the CU may be associated with multiple DUs. The CU may corresponds to the gNB, and the DU may corresponds to the cell.

[0062] In some embodiments, the terminal device 110 sends 301 L3 measurement report 302 to source DU 381. The source DU 381 sends 304 ULRRC message transfer 305 which comprises the L3 measurement report. The source CU 382 performs the LTM Candidate preparation 307.

[0063] The source CU 382 sends 308 LTM handover HO request 309 to target CU 383. The LTM HO request comprises the list of candidate cells and beam level measurements for each candidate from L3 -measurement-report. The handover request message includes the L3 measurement report to enable candidate CU to identify its target cells for subsequent LTM. Optionally, the first network device 121 transmits to the second network device 122, theidentifier identifying the candidate network device. Specifically, the HO request may also comprises the LTM-ResourceConfig-Group-ID for identifying the candidate network device.

[0064] In some embodiments, the second network device 122 transmit to the first network device 121 a handover response for the LTM. The handover response comprises a first LTM configuration for one or more candidate cells of candidate network device. The first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating the association between the LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device 121 and the second network device 122. The indication comprises an identifier identifying the candidate network device.

[0065] Specifically, as shown in FIG. 3, the target CU 383 perform 311 LTM admission control. The target CU 383 prepare 312 single resource set for all candidate cells of CU and one resource-set mapped to multiple report-config of different candidate cells. The target CU 383 sends 313 UE context setup request 314 to target DU 384. The UE context setup request comprises common LTM-CSI-RS-Resource-config. The target DU 384 sends LTM-CSI- Report-config which pointing LTM-CSI-RS-Resource-config prepared by the target CU 383. The target CU 383 sends LTM HO response 320 to the source CU 382. The LTM HO response comprises LTM-CSI-Resource-set-for-Group and LTM-Candidate-Config. The LTM-CSL Resource-set-for-Group is the resource set per candidate network device, such as the second network device 122. Therefore, each candidate-gNB (such as network device 122) provides ‘LTM-ResourceConfig-Group-ID’ for its resource configurations. The LTM-Resource- Config-Group-ID is used to link the LTM CSI resource configurations to its respective gNB uniquely. Separate LTM CSI resource configurations (i.e., LTM-CSI-ResourceConfigs) are prepared by each candidate gNB based on the indication from source gNB for LTM Handover request.

[0066] In some embodiments, the source CU 382 sends 322 the UE context modification request 323 to the source DU 381. The UE context modification request comprises the LTM- CSLResource-set. In addition, the source DU 381 sends 326 the UE context modification response to the source CU 382. The UE context modification response comprises the LTM- CSI-Report-config pointing to LTM-CSI-Resource-config.

[0067] In some embodiments, the first network device 121 determines the second LTM configuration based on the first LTM configuration. Specifically, as shown in FIG. 3, thesource CU 382 generates 328 the RRC Reconfiguration containing the LTM-CSI-Resource- Config-List and LTM-Candidate-List. The LTM-CSI-Resource-Config-List comprises the Resource-set-Group-ID which is unique-ID for each candidate CU and LTM-CSI-Resource- Configuration. The LTM-Candidate-List comprises the Resource-set-Group-ID. The source CU 382 sends 329 the DL RRC message transfer 330 which comprises RRC message to the source DU 381. The source DU 381 sends 332 RRC Reconfiguration 333 to the terminal device 110. Therefore, the source gNB (such as the first network device 121) provides the RRC Configuration containing list of LTM CSI resource configurations towards UE along with binding to respective gNB. Each candidate cell is also configured with ‘LTM-Resource- Config-Group-ID’. Final configuration will have N LTM CSI resource configurations where N -> number of gNBs involved.

[0068] In some embodiments, the terminal device 110 sends 335 the RRC Reconfiguration Complete 336 to the source DU 381. The source DU 381 sends 338 the UL RRC message transfer 339 to the source CU 382. The DL synchronization with candidate cells 341 is performed. The source DU 381 sends 342 the PDCCH Order 343 to the terminal device 110. The terminal device 110 send 345 RA 346 to the target DU 384. In addition, the target DU 384 sends the TA 349 for the terminal device 110 to the source DU 381.

[0069] In some embodiments, the indication in the LTM configuration is a parameter of a report configuration in each candidate configuration for LTM, and the indication is for identifying a resource in the LI measurement configuration. Specifically, as shown in FIG.3, the terminal device 110 perform 351 the LI measurement refer to LTM-CSI-RS-Config of the Resource-set-Group-ID of serving cell. The Resource-set-Group-ID is for identifying the LTM-CSI-RS-Config. Therefore, the terminal device 110 uses the LTM CSI resource configurations corresponds to the LTM-Resource-Config-Group-ID of current serving cell for LI measurements.

[0070] In some embodiments, the terminal device 110 sends 352 the LI measurement report 353 to the source DU 381. In addition, the source DU 381 determines 355 the decision of serving cell change. The source DU 381 sends 356 MAC CE trigger cell change 357. The MAC CE contains the TA for target cell. The terminal device 110 performs 360 the Random access process with target DU 384. In addition, the terminal device 110 sends 362 RRC Reconfiguration Complete 363 to the target DU 384. The target DU 384 sends 365 the UL RRC message transfer 366 to the target CU 383. The target DU 384 sends 368 the access notification 369 to the target CU 383. The target CU 383 sends 371 the LTM HO complete372 to the source CU 382. The source CU 382 sends 374 the UE context release command 375 to the source DU 381. The source DU 381 sends 377 the UE context release complete 379 to the source CU 382. Then the Path switch is performed 379.

[0071] FIG. 3B illustrates an example of RRC structure for inter-node LTM according to some embodiments of the present disclosure. As shown in FIG. 3B, the block 390 is the structure of LTM-Configuration. In addition, the LTM-Configuration comprises the LTM- Candidate-List for the configuration of candidate cells for LTM. The block 391 is the structure of the LTM-Candidate-List. In addition, the new parameter of LTM-Resource- Group-ID is included. The block 390 also comprises the LTM-CSI-Resource-Config_List for the resource configuration of measurement for LTM. The LTM-CSI-Resource-Config_List comprises multiple LTM-CSI-Resource-Config. In addition, each CSI-Resource-Config associated with a LTM-Resource-Group-ID. Each CSI-Resource-Config comprises multiple of RRC structure of block 392, which comprises the detail SSB resource configuration and the associated candidate cells. At block 391, the LTM-Candidate-Config(RRC) comprises the CSI-Meas-Config, which is shown as block 393. In addition, the CSI-Meas-Config comprises the LTM-CSI-Report-Config-List for the configuration of CSI measurement report for LTM. The LTM-CSI-Report-Config-List comprises multiple LTM-CSI-Report-Configs which comprises the LTM-Resource-For-Channel-measurement. According to the RRC structure, the terminal device 110 can get the related LTM-CSI-Resource-Config by the LTM- Resource-Group-ID.

[0072] FIG. 4 A illustrates a flowchart illustrating another example of process for inter-node LTM according to some embodiments of the present disclosure. In FIG. 4A, there is detailed signaling workflow to support above-mentioned solution. For the purpose of discussion, the process 400 will be described with reference to FIG. 1. The process 400 may involve the terminal device 110, the first network device 121 and the second network device 122 as illustrated in FIG. 1. It would be appreciated that although the process 400 has been described in the communication system 100 of FIG. 1, this process may be likewise applied to other communication scenarios where different network devices are jointly deployed to provide respective serving cells.

[0073] In some embodiments, as shown in FIG. 4 A, the first network device 121 comprises a source CU 492 and a source DU 491 for the LTM, and the second network device 122 comprises a target CU 493 and a target DU 494 for the LTM. In addition, the number of CU and DU is just example, the CU may be associated with multiple DUs. The CU maycorresponds to the gNB, and the DU may corresponds to the cell.

[0074] In some embodiments, the terminal device 110 sends 401 L3 measurement report 402 to source DU 491. The source DU 491 sends 404 UL RRC message transfer 405 which comprises the L3 measurement report. The source CU 492 performs the LTM Candidate preparation 407.

[0075] In some embodiments, the first network device 121 transmit to the second network device 122 the identifier identifying the candidate network device. Specifically, as shown in FIG. 4A, the source CU 492 sends 408 LTM HO request 409 to target CU 493. The LTM HO request comprises the list of candidate cells and beam level measurements for each candidate from L3 -measurement-report and Resource-Set-Group-ID. The Resource-Set-Group-ID is for identifying the candidate network device. The handover request message includes the L3 measurement report to enable candidate CU to identify its target cells for subsequent LTM.

[0076] In some embodiments, the second network device 122 transmit, to the first network device 121, a handover response for the LTM. The handover response comprises a first LTM configuration for one or more candidate cells of candidate network device. The first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating the association between the LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device 121 and the second network device 122. The indication comprises an identifier identifying the candidate network device. In addition, the indication comprises a first identifier identifying the candidate network device and a second identifier associated with reference signal resource configuration for the LI measurement.

[0077] Specifically, as shown in FIG. 4A, the target CU 493 perform LTM admission control 411. The target CU 493 prepare single resource set for all candidate cells of CU and one resource-set mapped to multiple report-config of different candidate cells 412. The target CU 493 sends 413 UE context setup request 414 to target DU 494. The UE context setup request comprises Resource-Set-Group-ID using for resource-Ref. The target DU 494 sends UE context setup response 417. The UE context setup response comprises the LTM-CSL Report-config with Resource-Set-Ref, which comprises Resource-Set-Group-ID and Resource-set-ID. The Resource-Set-Group-ID is for identifying the candidate network device. The Resource-set-ID is associated with reference signal resource configuration for the LI measurement. The target CU 493 sends 419 LTM HO response 420 to the source CU 492.The LTM HO response comprises Resource-set-Ref for each resource and the LTM- Candidate-Config.

[0078] In some embodiments, the source CU 492 sends 422 the UE context modification request 423 to the source DU 491. The UE context modification request comprises the LTM- CSI-Resource-set. In addition, the source DU 491 381 sends 326 the UE context modification response to the source CU 492. The UE context modification response comprises the LTM- CSI-Report-config with Resource-Set-Ref, which comprises Resource-Set-Group-ID and Resource-set-ID.

[0079] Therefore, separate LTM CSI resource configurations are prepared by each candidate gNB (such as the second network device 122 and the first network device 121), containing multiple resource-sets, each with a resource-set-index. When each candidate gNB prepares its candidate cell (DU) for report-configuration, the report-configuration includes ‘report-reference’ (also denoted as Resource-set-Ref herein) that consists of LTM-Resource- group-ID and the resource-set-index. The LTM-Resource-Group-ID is assigned uniquely across the candidate gNBs involved in the LTM.

[0080] In some embodiments, the first network device 121 determines the second LTM configuration based on the first LTM configuration. The duplicates of the LI measurement configurations in the first LTM configuration are removed, and the first identifier and the second identifier for each of the LI measurement configuration are added. And , each of the LI measurement configuration is associated with one or more combinations of the first identifier and the second identifier. Specifically, as shown in FIG. 4A, the source CU 492 consolidate 428 all LTM-C Si-Resource entries by removing duplicates across candidate gNB. In addition, each entry will have list of Resource-set-Ref for single entry.

[0081] FIG. 4B illustrates an example of preparing the second LTM configuration based on the first LTM configuration. As shown in FIG. 4B, there are two CUs, Cl and C2. The LTM CSI resource configuration of Cl has four sets. Each set has four items of SSB resources with four items of corresponding cells. The four sets have the associated Resource-set-Ref (Ref 1- Ref 4) respectively. The LTM CSI resource configuration of C2 also has four sets. Each set has four items of SSB resources with four corresponding cells. The four sets have the associated Resource-set-Ref (Ref 5-Ref 8) respectively.

[0082] As shown in FIG. 4B, the LTM-Resource-set configurations from different gNBs (such as Cl and C2) having same resource sets. In this example, the set with Ref=4 of Clconfiguration and the set with Ref=7 of C2 configuration have same resource to measure (all the SSBs of C3, that is, C3-S1, C3-S2, C3-S3, C3-S4). When source gNB (such as the first network device 121) receives these entries, it removes the duplicate entries and create final list containing only 7 entries (Setl-Set7) towards UE. At each index the Report-ref-list (list of Resource-set-Ref) is including that is used in report-configuration (report-configuration points to a Resource-set-Ref). For the 4th index there will be two references (See Set- Mapping, Ref 4 and Ref 7). Ref 4 is from Cl and Ref 7 is from C2. For LTM measurements, terminal device 110 finds the resource set based on report-reference (Resource-set-Ref). For the index 4 there will be two report-references. This allows the terminal device 110 to measure C3 by the one entry of S4 with 2 references. So the measurement can be from Cl and also from C2 but without duplicating the entries.

[0083] Therefore, the serving gNB (such as the first network device 121) consolidates the multiple instances of LTM CSI Resource configuration into single container by removing duplicate entries across the sets. When such duplicate entries are removed, the container includes the report-reference pointed by each gNB in each index as ‘report-reference-list’ (list of Resource-set-Ref).

[0084] In some embodiments, as shown in FIG. 4A, the source CU 492 generate 429 the RRC Reconfiguration containing the LTM-CSI-Resource-Config which comprises each entry with list of Resource-set-ref. The RRC Reconfiguration also contains the LTM candidate config with RRC-Configuration. The RRC-Configuration comprises the LTM- CSLResource-config and Resource-set-ref. The source CU 492 sends 430 the DL RRC message transfer 431 which comprises RRC message to the source DU 491. The source DU 491 sends 433 RRC Reconfiguration 434 to the terminal device 110. Therefore, the terminal device 110 receives single LTM-CSI-Resource-configuration containing multiple resourcesets with each resource-set including report-reference-list (list of Resource-set-Ref) that consists of Resource-set-Ref used by candidate cells for the resource-set.

[0085] In addition, the terminal device 110 sends 436 the RRC Reconfiguration Complete 437 to the source DU 491. The source DU 491 sends 439 the UL RRC message transfer 440 to the source CU 492. The DL synchronization with candidate cells is performed 442. The source DU 491 sends 443 the PDCCH Order 444 to the terminal device 110. The terminal device 110 send 446 RA 447 to the target DU 494. In addition, the target DU 494 sends the TA 450 for the terminal device 110 to the source DU 491.

[0086] In some embodiments, the first identifier and second identifier are parameters of a report configuration in each candidate configuration for LTM, and the first identifier and the second identifier are for identifying a resource in the LI measurement configuration. Specifically, as shown in FIG.4A, at 452, the resource set within LTM-CSI-RS-Config is identified as index matching to the Resource-set-Ref. The Resource-set-Ref comprises Resource-Set-Group-ID and Resource-set-ID. Therefore, for starting LI measurement report for the LTM Report, the terminal device 110 identify the resource-set within the LTM-CSI- Resource-configuration container by searching its ‘report-reference’ (Resource-set-Ref) in the entry.

[0087] In some embodiments, the terminal device 110 sends 453 the LI measurement report 454 to the source DU 491. In addition, the source DU 491 determines 456 the decision of serving cell change. The source DU 491 sends 457 MAC CE trigger cell change 458. The MAC CE contains the TA for target cell. The terminal device 110 performs 461 the Random access process with target DU 494. In addition, the terminal device 110 sends 463 RRC Reconfiguration Complete 464 to the target DU 494. The target DU 494 sends 466 the UL RRC message transfer 467 to the target CU 493. The target DU 494 sends 469 the access notification 470 to the target CU 493. The target CU 493 sends 472 the LTM HO complete 473 to the source CU 492. The source CU 492 sends 475 the UE context release command 476 to the source DU 491. The source DU 491 sends 478 the UE context release complete 479 to the source CU 492. Then the Path switch is performed 481.

[0088] FIG. 4C illustrates an example of another RRC structure for inter node LTM according to some embodiments of the present disclosure. As shown in FIG. 4C, the block 496-Ais the structure of LTM-Configuration. In addition, the LTM-Configuration comprises the LTM-Candidate-List for the configuration of candidate cells for LTM. The block 496-B is the structure of the LTM-Candidate-List. The block 496-A also comprises the LTM-CSL Resource-Config List for the resource configuration of measurement for LTM. The LTM- CSLResource-Config List comprises multiple LTM-CSI-Resource-Config. Each CSL Resource-Config comprises RRC structure of block 496-C, which comprises the detail SSB resource configuration and the associated candidate cells, and the List-of Resource-set-Ref. At block 396-B, the LTM-Candidate-Config(RRC) comprises the CSI-Meas-Config, which is shown as block 496-D. In addition, the CSI-Meas-Config comprises the LTM-CSI-Report- Config-List for the configuration of CSI measurement report for LTM. The LTM-CSL Report-Config-List comprises multiple LTM-CSI-Report-Configs, which comprises theLTM-Resource-For-Channel-measurement and Resource-set-Ref. According to the RRC structure, terminal device 110 can find the resource-set in the LTM-CSI-Resource-Set based on Resource-set-Ref.

[0089] FIG. 5 illustrates the overall of solutions for inter node LTM according to some embodiments of the present disclosure. As shown in FIG. 5, the solution shown in FIGS. 3 A- 3B is that each gNB can decide on the LI measurement objects for its candidate-cells. So multiple-sets needed for each involved GNB. In addition, there can be duplicate entries across resource sets. The resource-sets (the circles for RS) indicates set of <candidate-cell and SSB> to be mapped to one or more report-configurations within same gNB. It is possible that same resource-set (the circle for RS in the figure) can be configured at different gNB. Because the target cells / beams for measurements can be same across candidate cells for some subset. So repetition of similar information across multiple instances may exist. In addition, for the solution shown in FIGs 4A-4C, all resource-sets of gNB consolidated to single Set. Indirect mapping to resource via reference to avoid the mapping issues with consolidation.

[0090] In view of the above description of the various embodiments of the present disclosure, these embodiments of the present disclosure take the advantages that a framework for resource configuration for inter-gNB LTM is provide, and an efficient resource configuration for reporting of LTM HO measurements for the UE in inter-gNB scenario is also provided.

[0091] FIG. 6 shows a flowchart of an example method 600 implemented at a terminal device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 600 will be described from the perspective of the terminal device 110 with reference to FIG. 1.

[0092] At block 610, the terminal device receives, from a first network device, a LTM configuration for one or more candidate cells of candidate network devices. The LTM configuration comprises an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device and a second network device. At block 620, the terminal device determines, an LI measurement configuration for a candidate cell among the one or more candidate cells based on the indication and the LTM configuration. At block 630, the terminal device performs, LI measurement for the candidate cell based on the LI measurement configuration.

[0093] In some embodiments, the indication comprises an identifier identifying the candidate network device.

[0094] In some embodiments, the indication is a parameter of a report configuration in each candidate configuration for LTM, and the indication is for identifying a resource in the LI measurement configuration.

[0095] In some embodiments, the indication comprises a first identifier identifying the candidate network device and a second identifier associated with a reference signal resource configuration for the LI measurement.

[0096] In some embodiments, the first identifier and second identifier are parameters of a report configuration in each candidate configuration for LTM, and the first identifier and the second identifier are for identifying a resource in the LI measurement configuration.

[0097] In some embodiments, the first network device comprises a source centralized unit (CU) and a source distributed unit (DU) for the LTM, and the second network device comprises a target CU and a target DU for the LTM.

[0098] FIG. 7 shows a flowchart of an example method 700 implemented at a first network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 700 will be described from the perspective of the first network device 121 with reference to FIG. 1.

[0099] At block 710, the first network device transmits, to a second network device, a handover request for LTM. At block 720, the first network device receives, from the second network device, a handover response for the LTM. The handover response comprises a first LTM configuration for one or more candidate cells of candidate network devices. The first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device and the second network device. At block 730, the first network device transmits, to a terminal device, a second LTM configuration for candidate cells of the candidate network devices. The second LTM configuration comprises an indication indicating the association between the LI measurement configuration for the candidate cells and the candidate network devices.

[0100] In some embodiments, the indication comprises an identifier identifying the candidate network device.

[0101] In some embodiments, the indication is a parameter of a report configuration in each candidate configuration for LTM, and the indication is for identifying a resource in the LI measurement configuration.

[0102] In some embodiments, the indication comprises a first identifier identifying the candidate network device and a second identifier associated with reference signal resource configuration for the LI measurement.

[0103] In some embodiments, the first identifier and second identifier are parameters of a report configuration in each candidate configuration for LTM, and the first identifier and the second identifier are for identifying a resource in the LI measurement configuration.

[0104] In some embodiments, the first network device transmits, to the second network device, the identifier identifying the candidate network device.

[0105] In some embodiments, the first network device determines the second LTM configuration based on the first LTM configuration.

[0106] In some embodiments, the first network device determining the second LTM configuration based on the first LTM configuration by removing duplicates of the LI measurement configurations and adding the first identifier and the second identifier for each of the LI measurement configuration. And each of the LI measurement configuration is associated with one or more combinations of the first identifier and the second identifier.

[0107] In some embodiments, the first network device comprises a source U and a source DU for the LTM, and the second network device comprises a target CU and a target DU for the LTM.

[0108] FIG. 8 shows a flowchart of an example method 800 implemented at a second network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 800 will be described from the perspective of the second network device 122 with reference to FIG. 1.

[0109] At block 810, receive, the second network device receives from a first network device, a handover request for LTM. At block 820, the second network device transmits, to the first network device, a handover response for the LTM. The handover response comprises a first LTM configuration for one or more candidate cells of candidate network device. The first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating the association between the LI measurementconfigurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device and the second network device.

[0110] In some embodiments, the indication comprises an identifier identifying the candidate network device.

[0111] In some embodiments, the indication is a parameter of a report configuration in each candidate configuration for LTM, and the indication is for identifying a resource in the LI measurement configuration.

[0112] In some embodiments, the indication comprises an identifier identifying the candidate network device and an identifier associated with reference signal resource configuration for the LI measurement.

[0113] In some embodiments, the first identifier and second identifier are parameters of a report configuration in each candidate configuration for LTM, and the first identifier and the second identifier are for identifying a resource in the LI measurement configuration.

[0114] In some embodiments, the first network device receives, from the first network device, the identifier identifying the candidate network device.

[0115] In some embodiments, the second network device comprises a target CU and a target DU for the LTM, and the second network device transmits, from the target CU, the LI measurement configuration to the target DU after receiving the handover request from the first network device. The LI measurement configuration comprises the identifier identifying the candidate device.

[0116] In some embodiments, the second network device receives, from the DU, a LI measurement report configuration. The LI measurement report configuration comprises an indication indicating the association between the LI measurement configurations for the one or more candidate cells and the candidate network device, the LI measurement configuration is associated with the LI measurement report.

[0117] In some embodiments, an apparatus capable of performing any of the method 600 (for example, the terminal device 110) may comprise means for performing the respective steps of the method 600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0118] In some embodiments, the apparatus comprises means for receiving, from a first network device, a LTM configuration for one or more candidate cells of candidate networkdevices. The LTM configuration comprises an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device and a second network device. The apparatus comprises means for determining, an LI measurement configuration for a candidate cell among the one or more candidate cells based on the indication and the LTM configuration. The apparatus comprises means for performing, LI measurement for the candidate cell based on the LI measurement configuration.

[0119] In some embodiments, the indication comprises an identifier identifying the candidate network device.

[0120] In some embodiments, the indication is a parameter of a report configuration in each candidate configuration for LTM, and the indication is for identifying a resource in the LI measurement configuration.

[0121] In some embodiments, the indication comprises a first identifier identifying the candidate network device and a second identifier associated with a reference signal resource configuration for the LI measurement.

[0122] In some embodiments, the first identifier and second identifier are parameters of a report configuration in each candidate configuration for LTM, and the first identifier and the second identifier are for identifying a resource in the LI measurement configuration.

[0123] In some embodiments, the first network device comprises a source centralized unit (CU) and a source distributed unit (DU) for the LTM, and the second network device comprises a target CU and a target DU for the LTM.

[0124] In some embodiments, an apparatus capable of performing any of the method 700 (for example, the network device 121) may comprise means for performing the respective steps of the method 700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0125] In some embodiments, the apparatus comprises means for transmitting, to a second network device, a handover request for LTM. The apparatus comprises means for receiving, from the second network device, a handover response for the LTM. The handover response comprises a first LTM configuration for one or more candidate cells of candidate network devices. The first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate networkdevices. The candidate network devices comprise the first network device and the second network device. The apparatus comprises means for transmitting, to a terminal device, a second LTM configuration for candidate cells of the candidate network devices. The second LTM configuration comprises an indication indicating the association between the LI measurement configuration for the candidate cells and the candidate network devices.

[0126] In some embodiments, the indication comprises an identifier identifying the candidate network device.

[0127] In some embodiments, the indication is a parameter of a report configuration in each candidate configuration for LTM, and the indication is for identifying a resource in the LI measurement configuration.

[0128] In some embodiments, the indication comprises a first identifier identifying the candidate network device and a second identifier associated with reference signal resource configuration for the LI measurement.

[0129] In some embodiments, the first identifier and second identifier are parameters of a report configuration in each candidate configuration for LTM, and the first identifier and the second identifier are for identifying a resource in the LI measurement configuration.

[0130] In some embodiments, the apparatus comprises means for transmitting, to the second network device, the identifier identifying the candidate network device.

[0131] The apparatus comprises means for determining the second LTM configuration based on the first LTM configuration.

[0132] In some embodiments, the apparatus comprises means for determining the second LTM configuration based on the first LTM configuration by removing duplicates of the LI measurement configurations and adding the first identifier and the second identifier for each of the LI measurement configuration. And each of the LI measurement configuration is associated with one or more combinations of the first identifier and the second identifier.

[0133] In some embodiments, the first network device comprises a source CU and a source DU for the LTM, and the second network device comprises a target CU and a target DU for the LTM.

[0134] In some embodiments, an apparatus capable of performing any of the method 800 (for example, the network device 122) may comprise means for performing the respective steps of the method 800. The means may be implemented in any suitable form. For example,the means may be implemented in a circuitry or software module.

[0135] In some embodiments, the apparatus comprises means for receiving from a first network device, a handover request for LTM. The apparatus comprises means for transmitting, to the first network device, a handover response for the LTM. The handover response comprises a first LTM configuration for one or more candidate cells of candidate network device. The first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating the association between the LI measurement configurations for the one or more candidate cells and the candidate network devices. The candidate network devices comprise the first network device and the second network device.

[0136] In some embodiments, the indication comprises an identifier identifying the candidate network device.

[0137] In some embodiments, the indication is a parameter of a report configuration in each candidate configuration for LTM, and the indication is for identifying a resource in the LI measurement configuration.

[0138] In some embodiments, the indication comprises an identifier identifying the candidate network device and an identifier associated with reference signal resource configuration for the LI measurement.

[0139] In some embodiments, the first identifier and second identifier are parameters of a report configuration in each candidate configuration for LTM, and the first identifier and the second identifier are for identifying a resource in the LI measurement configuration.

[0140] In some embodiments, the first network device receives, from the first network device, the identifier identifying the candidate network device.

[0141] In some embodiments, the second network device comprises a target CU and a target DU for the LTM, and the second network device transmits, from the target CU, the LI measurement configuration to the target DU after receiving the handover request from the first network device. The LI measurement configuration comprises the identifier identifying the candidate device.

[0142] In some embodiments, the second network device receives, from the DU, a LI measurement report configuration. The LI measurement report configuration comprises an indication indicating the association between the LI measurement configurations for the oneor more candidate cells and the candidate network device, the LI measurement configuration is associated with the LI measurement report.

[0143] FIG. 9 is a simplified block diagram of a device 900 that is suitable for implementing embodiments of the present disclosure. The device 900 may be provided to implement the communication device, for example the terminal device 110, the network device 121, and the network device 122 as shown in FIG. 1. As shown, the device 900 includes one or more processors 910, one or more memories 920 coupled to the processor 910, and one or more communication modules 940 coupled to the processor 910.

[0144] The communication module 940 is for bidirectional communications. The communication module 940 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

[0145] The processor 910 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 900 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

[0146] The memory 920 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 924, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), and other magnetic storage and / or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 922 and other volatile memories that will not last in the power-down duration.

[0147] A computer program 930 includes computer executable instructions that are executed by the associated processor 910. The program 930 may be stored in the ROM 920. The processor 910 may perform any suitable actions and processing by loading the program 930 into the RAM 922.

[0148] The embodiments of the present disclosure may be implemented by means of the program 930 so that the device 900 may perform any process of the disclosure as discussed with reference to FIGS. 2 to 8. The embodiments of the present disclosure may also beimplemented by hardware or by a combination of software and hardware.

[0149] In some embodiments, the program 930 may be tangibly contained in a computer readable medium which may be included in the device 900 (such as in the memory 920) or other storage devices that are accessible by the device 900. The device 900 may load the program 930 from the computer readable medium to the RAM 922 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. FIG. 10 shows an example of the computer readable medium 1000 in form of CD or DVD. The computer readable medium has the program 830 stored thereon.

[0150] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0151] 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 those included in program modules, being executed in a device on a target real or virtual processor, to carry out the methods 600-800 as described above with reference to FIGS. 6-8. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[0152] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may beprovided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[0153] In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

[0154] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, 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 disc read-only memory (CD- ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).

[0155] Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

[0156] Although the present disclosure has been described in languages specific to structural features and / or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

WHAT IS CLAIMED IS:

1. A terminal device comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to: receive, from a first network device, a layer 1 (Ll) / layer 2 (L2) triggered mobility (LTM) configuration for one or more candidate cells of candidate network devices, wherein the LTM configuration comprises an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices, and the candidate network devices comprise the first network device and a second network device; determine, an LI measurement configuration for a candidate cell among the one or more candidate cells based on the indication and the LTM configuration; and perform, LI measurement for the candidate cell based on the LI measurement configuration.

2. The terminal device of claim 1, wherein the indication comprises an identifier identifying the candidate network device.

3. The terminal device of claim 1 or 2, wherein the indication is a parameter of a report configuration in each candidate configuration for LTM, and the indication is for identifying a resource in the LI measurement configuration.

4. The terminal device of claim 1, wherein the indication comprises a first identifier identifying the candidate network device and a second identifier associated with a reference signal resource configuration for the LI measurement.

5. The terminal device of claim 4, wherein the first identifier and second identifier are parameters of a report configuration in each candidate configuration for LTM, and the first identifier and the second identifier are for identifying a resource in the LI measurement configuration.

6. The terminal device of any of claims 1-5, wherein the first network devicecomprises a source centralized unit (CU) and a source distributed unit (DU) for the LTM, and the second network device comprises a target CU and a target DU for the LTM.

7. A first network device comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first network device at least to: transmit, to a second network device, a handover request for layer 1 (Ll) / layer 2 (L2) triggered mobility (LTM); receive, from the second network device, a handover response for the LTM, wherein the handover response comprises a first LTM configuration for one or more candidate cells of candidate network devices, the first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices, and the candidate network devices comprise the first network device and the second network device; and transmit, to a terminal device, a second LTM configuration for candidate cells of the candidate network devices, wherein the second LTM configuration comprises an indication indicating the association between the LI measurement configuration for the candidate cells and the candidate network devices.

8. The first network device of claim 7, wherein the indication comprises an identifier identifying the candidate network device.

9. The first network device of claim 7 or 8, wherein the indication is a parameter of a report configuration in each candidate configuration for LTM, and the indication is for identifying a resource in the LI measurement configuration.

10. The first network device of claim 7, wherein the indication comprises a first identifier identifying the candidate network device and a second identifier associated with reference signal resource configuration for the LI measurement.

11. The first network device of claim 10, wherein the first identifier and second identifier are parameters of a report configuration in each candidate configuration for LTM,and the first identifier and the second identifier are for identifying a resource in the LI measurement configuration.

12. The first network device of any of claims 7-11, wherein the first network device is further caused to: transmit, to the second network device, the identifier identifying the candidate network device.

13. The first network device of any of claims 7-12, wherein the first network device is further caused to: determine the second LTM configuration based on the first LTM configuration.

14. The first network device of claim 13, wherein determining the second LTM configuration based on the first LTM configuration comprises: removing duplicates of the LI measurement configurations; and adding the first identifier and the second identifier for each of the LI measurement configuration, each of the LI measurement configuration is associated with one or more combinations of the first identifier and the second identifier.

15. The first network device of any of claims 7-14, wherein the first network device comprises a source centralized unit (CU) and a source distributed unit (DU) for the LTM, and the second network device comprises a target CU and a target DU for the LTM.

16. A second network device comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second network device at least to: receive, from a first network device, a handover request for layer 1 (Ll) / layer 2 (L2) triggered mobility (LTM); transmit, to the first network device, a handover response for the LTM, wherein the handover response comprises a first LTM configuration for one or more candidate cells of candidate network device, the first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating the association between the LI measurement configurations for the one or more candidatecells and the candidate network devices, the candidate network devices comprise the first network device and the second network device.

17. The second network device of claim 16, wherein the indication comprises an identifier identifying the candidate network device.

18. The second network device of claim 16 or 17, wherein the indication is a parameter of a report configuration in each candidate configuration for LTM, and the indication is for identifying a resource in the LI measurement configuration.

19. The second network device of claim 16, wherein the indication comprises an identifier identifying the candidate network device and an identifier associated with reference signal resource configuration for the LI measurement.

20. The second network device of claim 19, wherein the first identifier and second identifier are parameters of a report configuration in each candidate configuration for LTM, and the first identifier and the second identifier are for identifying a resource in the LI measurement configuration.

21. The second network device of any of claims 17-20, wherein the first network device is further caused to: receive, from the first network device, the identifier identifying the candidate network device.

22. The second network device of any of claims 16-21, wherein the second network device comprises a target centralized unit (CU) and a target distributed unit (DU) for the LTM, and the second network device is further caused to: transmit, from the target CU, the LI measurement configuration to the target DU after receiving the handover request from the first network device, wherein the LI measurement configuration comprises the identifier identifying the candidate device.

23. The second network device of claim 22, wherein the second network device is further caused to: receive, from the DU, a LI measurement report configuration, wherein the LImeasurement report configuration comprises an indication indicating the association between the LI measurement configurations for the one or more candidate cells and the candidate network device, the LI measurement configuration is associated with the LI measurement report.

24. A method comprising: receiving, from a first network device, a layer 1 (Ll) / layer 2 (L2) triggered mobility (LTM) configuration for one or more candidate cells of candidate network devices, wherein the LTM configuration comprises an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices, and the candidate network devices comprise the first network device and a second network device; determining, an LI measurement configuration for a candidate cell among the one or more candidate cells based on the indication and the LTM configuration; and performing, LI measurement for the candidate cell based on the LI measurement configuration.

25. A method comprising: transmitting, to a second network device, a handover request for layer 1 (Ll) / layer 2 (L2) triggered mobility (LTM); receiving, from the second network device, a handover response for the LTM, wherein the handover response comprises a first LTM configuration for one or more candidate cells of candidate network devices, the first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices, and the candidate network devices comprise the first network device and the second network device; and transmitting, to a terminal device, a second LTM configuration for candidate cells of the candidate network devices, wherein the second LTM configuration comprises an indication indicating the association between the LI measurement configuration for the candidate cells and the candidate network devices.

26. A method comprising: receiving, from a first network device, a handover request for layer 1 (Ll) / layer 2 (L2)triggered mobility (LTM); transmitting, to the first network device, a handover response for the LTM, wherein the handover response comprises a first LTM configuration for one or more candidate cells of candidate network device, the first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating the association between the LI measurement configurations for the one or more candidate cells and the candidate network devices, the candidate network devices comprise the first network device and the second network device.

27. An apparatus comprising: means for receiving, from a first network device, a layer 1 (Ll) / layer 2 (L2) triggered mobility (LTM) configuration for one or more candidate cells of candidate network devices, wherein the LTM configuration comprises an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices, and the candidate network devices comprise the first network device and a second network device; means for determining, an LI measurement configuration for a candidate cell among the one or more candidate cells based on the indication and the LTM configuration; and means for performing, LI measurement for the candidate cell based on the LI measurement configuration.

28. An apparatus comprising: means for transmitting, to a second network device, a handover request for layer 1 (Ll) / layer 2 (L2) triggered mobility (LTM); means for receiving, from the second network device, a handover response for the LTM, wherein the handover response comprises a first LTM configuration for one or more candidate cells of candidate network devices, the first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating an association between LI measurement configurations for the one or more candidate cells and the candidate network devices, and the candidate network devices comprise the first network device and the second network device; and means for transmitting, to a terminal device, a second LTM configuration for candidate cells of the candidate network devices, wherein the second LTM configuration comprises an indication indicating the association between the LI measurementconfiguration for the candidate cells and the candidate network devices.

29. An apparatus comprising: means for receiving, from a first network device, a handover request for layer 1 (Ll) / layer 2 (L2) triggered mobility (LTM); means for transmitting, to the first network device, a handover response for the LTM, wherein the handover response comprises a first LTM configuration for one or more candidate cells of candidate network device, the first LTM configuration comprises an LI measurement configuration for the one or more candidate cells and an indication indicating the association between the LI measurement configurations for the one or more candidate cells and the candidate network devices, the candidate network devices comprise the first network device and the second network device.

30. A non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the method of any of claims 24-26.

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