Device, method and medium for communication

Abstract

Embodiments of the present disclosure relate to devices and methods for supporting Layer 1 or Layer 2 triggered mobility based on Layer 1 measurements. A first network device obtains a set of channel state information (CSI) resources associated with one or more candidate cells for at least one Layer 1 (L1) measurement, wherein the set of CSI resources is to be used by a terminal device to perform the at least one L1 measurement; and transmitting, via the transceiver, information indicating the set of CSI resources to a second network device serving the terminal device. In this way, the L1 measurement report supports LTM based on L1 measurements.

Description

Technical Field

[0001] Various embodiments of the present disclosure generally relate to the field of communications, and more particularly, to a network device, a terminal device, a method, and a non-transitory computer-readable medium for communications. Background Art

[0002] When a user equipment (UE) moves from one cell to another, at some point a serving cell change needs to be performed. Traditionally, serving cell changes are done through explicit radio resource control (RRC) reconfiguration signaling to trigger synchronization of the target cell based on L3 measurement reports. This results in longer latency, greater overhead, and longer outage times compared to beam-level mobility. Therefore, in 3GPP Release 18, a new work item, Further New Radio (NR) Mobility Enhancements called Layer 1 (L1) / Layer 2 (L2) Triggered Mobility (LTM), was approved to implement serving cell changes via L1 / L2 signaling in order to reduce latency, overhead, and outage times.

[0003] However, conventional L1 measurement reports (e.g., synchronization signal / physical broadcast channel block (SSB)-based measurements or channel state information reference signal (CSI-RS)-based measurements) do not support LTM. Therefore, a solution for supporting L1 measurements for LTM is needed. Summary of the Invention

[0004] Generally speaking, embodiments of the present disclosure provide a solution for communication, and in particular, a solution for supporting LTM based on L1 measurements.

[0005] In a first aspect, a first network device is provided. The first network device includes a processor and a transceiver coupled to the processor. The processor is configured to: obtain a set of channel state information (CSI) resources associated with one or more candidate cells for at least one L1 measurement, wherein the set of CSI resources is to be used by a terminal device to perform the at least one L1 measurement; and send, via the transceiver, information indicating the set of CSI resources to a second network device serving the terminal device.

[0006] In a second aspect, a second network device is provided. The second network device includes a processor and a transceiver coupled to the processor. The processor is configured to: obtain a set of CSI resources associated with one or more candidate cells for at least one L1 measurement, wherein the CSI resource set is to be used by a terminal device to perform the at least one L1 measurement; send information indicating the CSI resource set to the terminal device; and obtain at least one L1 measurement report.

[0007] In a third aspect, a terminal device is provided. The terminal device includes a processor and a transceiver coupled to the processor. The processor is configured to: receive, from a second network device serving the terminal device, information indicating a set of CSI resources associated with one or more candidate cells for at least one L1 measurement; perform at least one L1 measurement for the set of CSI resources; and send at least one L1 measurement report.

[0008] In a fourth aspect, a method performed by a first network device is provided, the method comprising: obtaining a set of CSI resources associated with one or more candidate cells for at least one L1 measurement, wherein the set of CSI resources is to be used by a terminal device to perform the at least one L1 measurement; and sending, via a transceiver, information indicating the set of CSI resources to a second network device serving the terminal device.

[0009] In a fifth aspect, a method performed by a second network device is provided, the method comprising: obtaining a set of CSI resources associated with one or more candidate cells for at least one L1 measurement, wherein the set of CSI resources is to be used by a terminal device to perform the at least one L1 measurement; sending information indicating the set of CSI resources to the terminal device; and obtaining at least one L1 measurement report.

[0010] In a sixth aspect, a method performed by a terminal network device is provided, the method comprising: receiving, from a second network device serving the terminal device, information indicating a set of CSI resources associated with one or more candidate cells for at least one L1 measurement; performing at least one L1 measurement for the set of CSI resources; and sending at least one L1 measurement report.

[0011] In a seventh aspect, a non-transitory computer-readable medium is provided. The non-transitory computer-readable medium has program instructions stored thereon. When executed by an apparatus, the program instructions cause the apparatus to at least: obtain a set of CSI resources associated with one or more candidate cells for at least one L1 measurement, wherein the CSI resource set is to be used by a terminal device to perform the at least one L1 measurement; and transmit, via a transceiver, information indicating the set of CSI resources to a second network device serving the terminal device.

[0012] In an eighth aspect, a non-transitory computer-readable medium is provided. The non-transitory computer-readable medium has program instructions stored thereon. When executed by an apparatus, the program instructions cause the apparatus to at least: obtain a set of CSI resources associated with one or more candidate cells for at least one L1 measurement, wherein the CSI resource set is to be used by a terminal device to perform the at least one L1 measurement; send information indicating the CSI resource set to the terminal device; and obtain at least one L1 measurement report.

[0013] In a ninth aspect, a non-transitory computer-readable medium is provided. The non-transitory computer-readable medium has program instructions stored thereon. When executed by an apparatus, these program instructions cause the apparatus to at least: receive, from a second network device serving a terminal device, information indicating a set of CSI resources associated with one or more candidate cells for at least one L1 measurement; perform at least one L1 measurement for the set of CSI resources; and transmit at least one L1 measurement report.

[0014] It should be understood that the invention summary is neither intended to identify the key features or essential features of the 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 readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Some embodiments will now be described with reference to the accompanying drawings, in which:

[0016] Figure 1A A schematic diagram illustrating a communication environment in which lower layer mobility within a distributed unit (DU) may be implemented;

[0017] Figure 1B A schematic diagram illustrating a communication environment in which lower layer mobility between DUs within a central unit (CU) can be implemented is shown;

[0018] Figure 1C A schematic diagram illustrating a communication environment in which some embodiments of the present disclosure may be implemented;

[0019] Figure 2A illustrates a signaling diagram illustrating a communication process according to some example embodiments of the present disclosure;

[0020] Figure 2B illustrates example CSI resource configurations according to some example embodiments of the present disclosure;

[0021] Figure 3 illustrates a message flow of a communication process according to some example embodiments of the present disclosure;

[0022] Figure 4A illustrates another message flow of a communication process according to some example embodiments of the present disclosure;

[0023] Figure 4B illustrates example CSI resource configurations according to some example embodiments of the present disclosure;

[0024] Figure 4C illustrates example CSI resource configurations according to some example embodiments of the present disclosure;

[0025] Figure 5Aillustrates yet another message flow of a communication process according to some example embodiments of the present disclosure;

[0026] Figure 5B illustrates an example CSI-measurement configuration according to some example embodiments of the present disclosure;

[0027] Figure 6 illustrates yet another message flow of a communication process according to some example embodiments of the present disclosure;

[0028] Figure 7 illustrates a flow chart of an example method implemented at a central unit or a first network device according to some embodiments of the present disclosure;

[0029] Figure 8 illustrates a flow chart of an example method implemented at a source unit or a second network device according to some embodiments of the present disclosure;

[0030] Figure 9 A flowchart illustrating an example method implemented at a terminal device according to some embodiments of the present disclosure; and

[0031] Figure 10 A simplified block diagram of an apparatus suitable for implementing various embodiments of the present disclosure is shown.

[0032] Throughout the drawings, the same or similar reference numerals denote the same or similar elements. DETAILED DESCRIPTION

[0033] The principles of the present disclosure are described with reference to some embodiments. It should be understood that these embodiments are described for illustrative purposes only and to help those skilled in the art understand and implement the present disclosure, and do not imply any limitation on the scope of the present disclosure. The disclosure described herein can be implemented in various ways different from those described below.

[0034] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0035] References in this disclosure to "some embodiments," "example embodiments," "an embodiment," "some embodiments," etc., indicate that the described embodiment(s) may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes the particular feature, structure, or characteristic. Moreover, these phrases are not necessarily referring to the same embodiment(s). Further, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, it should be understood that it is within the knowledge of those skilled in the art to implement such feature, structure, or characteristic in conjunction with other embodiments (whether or not explicitly described).

[0036] It should be understood that although the terms "first" and "second" etc. may be used to describe various elements in this article, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the embodiments, a first element may also be referred to as a second element, and similarly, a second element may also be referred to as a first element. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0037] The terms used herein are used only for the purpose of describing specific embodiments and are not intended to limit the example embodiments. As used herein, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are also intended to include the plural forms. It should also be understood that the terms "comprises", "comprising", "has", "having", "includes", and / or "including" when used herein specify the presence of the features, elements, and / or components, etc., but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0038] As used herein, the term "communication network" refers to a network that complies with any suitable communication standard, such as fifth generation (5G) NR, long term evolution (LTE), advanced LTE (LTE-A), wideband code division multiple access (WCDMA), high speed packet access (HSPA), narrowband Internet of Things (NB-IoT), etc. Further, the communication between the terminal equipment and the network equipment in the communication network can be performed according to any suitable generation communication protocol, including but not limited to first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, 5G communication protocols and / or any other protocols currently known or to be developed in the future. The various embodiments of the present disclosure can be applied to various communication systems. In view of the rapid development of communications, there will also be future types of communication technologies and systems in which the present disclosure can be embodied. The scope of the present invention should not be considered to be limited to the aforementioned systems.

[0039] As used herein, the term "network device" generally refers to a node in a communication network via which a terminal device can access the communication network and receive services therefrom. Depending on the terminology and technology applied, a network device may refer to a base station (BS) or an access point (AP), for example, a Node B (Node B or NB), a radio access network (RAN) node, an evolved Node B (eNodeB or eNB), a NR NB (also known as a gNB), a remote radio unit (RRU), a radio head (RH), infrastructure equipment for V2X (vehicle-to-everything) communication, a transmit receive point (TRP), a receive point (RP), a remote radio head (RRH), a relay, an integrated access backhaul (IAB) node, a low-power node (such as a femto BS, a pico BS, etc.).

[0040] As used herein, the term "terminal device" generally refers to any end device capable of wireless communication. By way of example and not limitation, a terminal device may also be referred to as a communication device, user equipment (UE), end user equipment, subscriber station (SS), unmanned aerial vehicle (UAV), portable subscriber station, mobile station (MS), or access terminal (AT). The terminal device may include, but is not limited to, a mobile phone, a cellular phone, a smart phone, a voice over IP (VoIP) phone, a wireless local loop phone, a tablet computer, a wearable terminal device, a personal digital assistant (PDA), a portable computer, a desktop computer, an image capture terminal device such as a digital camera, a game terminal device, a music storage and playback appliance, an in-vehicle wireless terminal device, a wireless endpoint, a mobile station, a laptop embedded device (LEE), a laptop mounted device (LME), a USB software dongle, a smart device, a wireless customer premises equipment (CPE), an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, a medical device (e.g., a remote surgical device), an industrial device (e.g., a robot and / or other wireless device operating in an industrial process chain context and / or an automated process chain context), a consumer electronic device, a device operating on a commercial wireless network and / or an industrial wireless network, etc. In the following description, the terms “terminal device,” “communication device,” “terminal,” “user equipment,” and “UE” may be used interchangeably.

[0041] As used herein, the terms "resource," "transmission resource," "resource block," "physical resource block," "uplink resource," "downlink resource," or "sidelink resource" may refer to any resource used to perform communication between a terminal device and a network device or between terminal devices, such as resources in the time domain, resources in the frequency domain, resources in the spatial domain, resources in the code domain, or any other resource that enables communication. Hereinafter, resources in both the frequency domain and the time domain will be used as examples of transmission resources for describing some embodiments of the present disclosure. It should be noted that the various embodiments of the present disclosure are equally applicable to other resources in other domains.

[0042] As mentioned above, when a UE moves from one cell to another, at some point, a serving cell change needs to be performed. Traditionally, serving cell changes are accomplished through explicit RRC reconfiguration signaling to trigger synchronization of the target cell based on L3 measurement reports. This results in longer latency, greater overhead, and longer outages compared to bundle-level mobility.

[0043] Therefore, in 3GPP Release 18, a new work item on further NR mobility enhancements (called LTM) was approved to implement serving cell changes via L1 / L2 signaling in order to reduce latency, overhead, and interruption time. Potential application scenarios of LTM include: Figure 1A The intra-CU and intra-DU mobility shown in Figure 1B Intra-CU inter-DU mobility is shown.

[0044] As for the intra-CU and intra-DU mobility scenarios, such as Figure 1A As shown, the UE moves between different cells within the same DU. In short, this situation is called intra-DU mobility. In this scenario, the UE moves among cells belonging to the same DU, and the DU is able to know the target cell within the candidate cells managed by the DU through the index of the candidate cell. For this scenario, candidate cells such as cell A and cell B are provided by the DU. Using LTM, the UE obtains multiple candidate cell (such as cell A and cell B) configurations via RRC reconfiguration before cell switching. Based on the L1 measurement report from the UE, the source DU selects one of the candidate cells (such as cell A and cell B) as the target cell, and triggers LTM cell switching by sending the index of the candidate cell configuration to the UE via the medium access control-control element (MAC CE). Each index is used to identify a candidate cell configuration for the UE. From the UE's perspective, the index indicates which candidate cell configuration the UE should apply / use / activate when the UE receives the LTM cell switching command (e.g., MAC CE).

[0045] However, in this scenario, Figure 1BAs shown in Figure 1, when a UE moves between different cells belonging to different DUs within the same CU. In short, this scenario is called inter-DU mobility. Figure 1B As shown, cell 1 belongs to DU1 as the source DU, cell 2 belongs to DU2 as the candidate DU, the UE moves from cell 1 to cell 2, and both DU1 and DU2 are in the same CU.

[0046] In this scenario, since cell 2 belongs to another DU 2, when receiving the L1 measurement report from the UE, the source DU 1 does not know the target cell (e.g., cell 2) through the index of cell 2. Therefore, in this scenario, the L1 measurement report does not support LTM based on L1 measurements.

[0047] In light of the foregoing discussion, various embodiments of the present disclosure provide a solution for supporting LTM based on L1 measurements. In one aspect of the solution disclosed herein, a first network device obtains a set of CSI resources associated with one or more candidate cells for at least one L1 measurement, where the CSI resource set is to be used by a terminal device to perform the at least one L1 measurement; and transmits information indicating the CSI resource set to a second network device serving the terminal device via a transceiver. Through this proposed solution, L1 measurement reporting can support LTM based on L1 measurements.

[0048] The principles and implementations of various embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0049] Sample computing environment

[0050] Figure 1C 1 illustrates a schematic diagram of a communication environment 100 in which some embodiments of the present disclosure may be implemented. Figure 1C As shown, the communication environment 100, which may also be referred to as a communication network 100 or a communication system 100, includes a CU 130 (which is sometimes also referred to as a first network device), a service or source DU 110 (which is sometimes also referred to as a second network device), and multiple candidate DUs 140 (which are sometimes also referred to as a third network device) and a terminal device 120. The gNB or network device may include a CU and a DU, and the CU and the DU are divided according to the real-time requirements of different protocol layers. Under this principle, the physical upper layer, medium access control, and radio link control (RLC) layers that require high real-time performance are placed in the DU for processing, while the packet data convergence protocol (PDCP) and RRC layers that do not require high real-time performance are placed in the CU for processing. The candidate DU 140 may manage multiple cells, for example, cells 141 to 144, and it should be noted that the number of candidate cells is for illustrative purposes only. The source DU 110 also manages multiple cells and serves the terminal device 120; however, as shown in FIG. Figure 1CAs shown, only one cell 111 out of multiple cells is shown. To send data and / or control information, the terminal device 120 may perform communication with the source DU 110. It should be noted that the candidate cell is within the source DU. That is to say, the candidate DU and the source DU are the same. For example, cells 141 to 144 and cell 111 are within the same DU (e.g., the source DU), and the candidate DU 140 and the source DU 110 are the same.

[0051] In traditional L1 measurement reporting, for SSB-based measurements, the UE shall report the SSB resource indicator (SSBRI), where SSBRIk (k≥[0]) corresponds to the (k + 1)-th configured entry in the relevant CSI-SSB-resource list within the corresponding CSI-SSB-resource set. For CSI-RS-based measurements, the UE shall report the CSI-RS resource indicator (CRI), where CRI k (k≥0) corresponds to the (k + 1)-th configured entry of the relevant NZP (non-zero power)-CSI-RS resource within the corresponding NZP-CSI-RS-resource set for channel measurement. The L1 measurement report may include multiple instances, where each instance is a <CRI, L1 measurement result> or <SSBRI, L1 measurement result> pair.

[0052] It can be seen that the traditional L1 measurement report includes a resource indicator. For traditional SSB-based measurements obtained from the candidate DU 140, SSBRI k corresponds to the (k + 1)-t-th entry in the configured SSB resource list. That is to say, the indicator only indicates the order of the measurement in the resource list of the SSB resource set configured by the candidate DU 140, but may not indicate the specific cell ID of the candidate DU 140. Therefore, based on the traditional L-1 measurement report obtained from the candidate DU 140, the source DU 110 cannot determine the target cell. That is to say, when the source DU 110 selects a target cell for LTM cell handover, since the traditional L1 measurement report does not include the cell identity (ID), the source DU 110 does not know how to select a target cell from the candidate cells provided by another DU (other than the source DU 110). That is to say, in particular, for the inter-DU scenario, the source DU 110 cannot select a target cell based on the traditional L1 measurement framework.

[0053] Although the network devices 110, 130, and 140 and the terminal device 120 are described in the communication environment 100 Figure 1C but the embodiments of the present disclosure can equally be applied to any other suitable communication devices that communicate with each other. That is to say, the embodiments of the present disclosure are not limited to Figure 1C the exemplary scenarios of Figure 1CIn the embodiment, network devices 110, 130, and 140 are schematically depicted as different parts of a base station, and terminal device 120 is schematically depicted as a mobile phone, but it should be understood that these depictions are exemplary in nature and do not imply any limitation. In other embodiments, network devices 110, 130, and 140 and terminal device 120 may be any other communication devices, for example, any other wireless communication device.

[0054] It should be understood that Figure 1C The specific number of various communication devices, the specific number of various communication links, the specific number of other elements, and the specific shape of the cells shown are for illustrative purposes only and do not imply any limitation. The communication environment 100 can include any suitable number of communication devices, any suitable number of communication links, any suitable number of other elements, and any suitable shape of cells suitable for implementing the embodiments of the present disclosure. In addition, it should be understood that various wireless communications and wired communications (if necessary) may exist between all communication devices.

[0055] Communications in the communication environment 100 may be implemented according to any suitable communication protocol(s), including but not limited to first generation (1G), second generation (2G), third generation (3G), fourth generation (4G), and fifth generation (5G) cellular communication protocols, NR-U, etc., wireless local area network communication protocols such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, etc., and / or any other protocols currently known or to be developed in the future. Moreover, such communications may utilize any suitable wireless communication technology, including 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 multiplexing (OFDM), discrete Fourier transform spread OFDM (DFT-s_OFDM), and / or any other technology currently known or to be developed in the future.

[0056] It should be understood that Figure 1C The number of devices (ie, network devices 110, 130, and 140 and terminal device 120) shown and their connection relationships and types are for illustrative purposes and do not imply any limitation. The system 100 may include any suitable number of devices suitable for implementing various embodiments of the present disclosure.

[0057] Example signaling diagram

[0058] Further, refer to Figure 2A , Figure 2A A signaling diagram illustrating a communication process 200 according to some example embodiments of the present disclosure is illustrated. For the purpose of discussion, reference will be made to Figure 1CProcess 200 is described, which may involve first network device 130, second network device 110, and terminal device 120. Hereinafter, network device 130 may also be referred to as a CU, and second network device 110 may also be referred to as a source DU 110 for serving terminal device 120.

[0059] The first network device 130 (e.g., a CU) obtains 205 a set of CSI resources associated with one or more candidate cells for L1 measurement. The set of CSI resources can be obtained from one or more candidate cells 141 to 144 by receiving the set of CSI resources configured by the candidate DU 140 or multiple candidate DUs 140. The first network device 130 then sends 210 information 201 indicating the set of CSI resources to the second network device 110 (e.g., the source DU 110 serving the terminal device 120). The second network device 110 then receives 215 the information 201 indicating the set of CSI resources. Although FIG2 shows the second network device 110 receiving 215 the information 201 from the first network device 130, it should be appreciated that the second network device 110 can obtain the information 201 in any other suitable manner. For example, instead of sending information indicating the CSI resources to source DU 110, first network device or CU 130 may transmit CSI resources obtained from candidate DU 140 to second network device or source DU 110, and then second network device or source DU 110 may obtain a set of CSI resources associated with one or more candidate cells.

[0060] In some embodiments, first network device 130 sends the obtained CSI resource set to second network device 110 , and second network device 110 determines or summarizes a set of CSI resource configurations for the CSI resource set associated with candidate cells 141 to 144 or any other cell from other candidate DUs 140 .

[0061] That is, since the CSI resource set is associated with one or more candidate cells, the CSI resource may include the identity of each candidate cell. When obtaining the CSI resource set from the CU 130, the source DU 110 obtains the CSI-resource and the corresponding cell ID of the candidate cell (in short, the candidate cell ID) from the CU 130. Thereafter, the source DU 110 summarizes the CSI-resource configuration (ResourceConfig), which includes the CSI-resource of the candidate cell and the corresponding candidate cell ID. The cell ID can be any of the following: a physical cell identity (PCI), a cell global identity (CGI), or a candidate configuration index, where each index is used to identify a candidate cell configuration.

[0062] CSI resources may be NZP-CSI-RS-resources and CSI-SSB-resources. For CSI-resource configuration, it can define a set of one or more NZP-CSI-RS-resource sets and / or CSI-SSB-resource sets. NZP-CSI-RS-resource sets may be NZP-CSI-RS resources, where each NZP-CSI-RS resource is configured to be measured by the UE. CSI-SSB-resource sets can be used to configure an SSB resource set, which includes one or more CSI-SSB-resource lists. Each CSI-SSB-resource list includes one or more SSB indexes.

[0063] In the above embodiment, the CSI resource configuration determined by the source DU 110 may be as follows: Figure 2B As shown. Figure 2B As shown, CSI-resource #0 is a CSI resource for the serving cell (e.g., cell 111 with PCI #0), CSI-resource #1 is a CSI resource for the candidate cell (e.g., cell 141 with PCI #1), CSI-resource #2 is a CSI resource for the candidate cell (e.g., cell 142 with PCI #2), and CSI-resource #3 is a CSI resource for the candidate cell (e.g., cell 143 with PCI #3).

[0064] In another embodiment, after receiving the CSI resource set from the candidate DU 140, the first network device 130 generates or determines a CSI resource configuration set for the CSI resource set associated with the candidate cell, and then sends the configuration set to the second network device 110. That is, the CU 130 obtains the CSI-resource and the corresponding candidate cell ID from the candidate DU 140 and summarizes the CSI-resource configuration. The CU 130 then sends the CSI-resource configuration to the UE 120, with the source DU 110 acting as a relay, so that the UE 120 can perform L1 measurements on the CSI resources configured in the CSI-resource configuration. The CU 130 also sends the CSI-resource configuration to the source DU 110 so that when the source DU 110 receives a CSI measurement report from the UE 120, the source DU 110 can know which candidate cell a particular measurement is associated with.

[0065] like Figure 2AAs shown, the second network device 110 sends 220 information 201 indicating a CSI resource set to the terminal device 120. In some embodiments, if the CSI resource configuration is determined by the first network device 130 itself, the first network device 130 directly sends information 201 to the second network device 110, where the information 201 includes the generated RRC reconfiguration message (e.g., via a DL RRC message transfer message). The RRC reconfiguration includes information 201. The source DU 110 then sends the RRC reconfiguration message to the terminal device 120. At the same time, since the second network device 110 needs to know the CSI resource set, the DL RRC message transfer message may also include the CSI-resource configuration for the candidate cell to the source DU 110, which will be used by the source DU 110 when determining the target cell.

[0066] However, in another embodiment, if the CSI resource configuration set is determined by the source DU 110, the source DU 110 sends the CSI resource configuration to the CU 130, and the CU 130 can then send a DL RRC messaging message to the source DU 110, which includes the generated RRC reconfiguration message. The RRC reconfiguration message includes the CSI-resource configuration for the serving cell (e.g., cell 111) and one or more candidate cells (e.g., cells 141 to 144). It should be noted that the CU 130 can also send the RRC reconfiguration message to the source DU 110 via other messages (e.g., a UE CONTEXT MODIFICATION REQUEST message). The source DU 110 then sends 220 information 201 indicating the CSI resource set to the terminal device 120 via, for example, the above-mentioned RRC reconfiguration message. The terminal device 120 receives 225 the information 201.

[0067] After receiving the information indicating the CSI resource set configured for the candidate cell, the terminal device 120 performs 230 at least one L1 measurement on the CSI resource set. After the measurement, the terminal device 120 sends 235 an L1 measurement report to the source DU 110. The source DU 110 receives the L1 measurement report from the terminal device 120. In another example, the terminal device 120 may also send the L1 measurement report to the candidate DU 140, which then sends the L1 measurement report to the CU 130, which in turn sends the L1 measurement report to the source DU 110. After receiving the L1 measurement report, the source DU 110 may select a target cell from the candidate cells.

[0068] Therefore, through process 200, source DU 110 can obtain the CSI-resources and corresponding candidate cell IDs for the candidate cells from the CU, and summarize the CSI-resource configuration including the CSI-resources of the candidate cells and the corresponding candidate cell IDs. Alternatively, CU 130 can obtain the CSI-resources of the candidate cells from candidate DU 140, and summarize the CSI-resource configuration including the CSI-resources of the candidate cells and the corresponding candidate cell IDs. Then, source DU 110 obtains the CSI-resource configuration of the candidate cells and the corresponding candidate cell IDs from CU 130.

[0069] By configuring CSI resources associated with candidate cells, since each CSI resource in the CSI resource configuration corresponds to a corresponding candidate cell and source DU 110 is aware of the CSI resource configuration, when source DU 110 receives a CSI resource measurement report, source DU 110 can determine the measurement for the corresponding CSI resource to associate with a specific candidate cell. In other words, source DU 110 can determine the target cell ID based on the L1 measurement report. Therefore, L1 measurements for CSI resource sets can support LTM based on L1 measurements, and source DU 110 can determine the target cell from the candidate cells based on the CRI or SSBRI in the L1 measurement report.

[0070] A scenario in which the CSI resource configuration is summarized by the candidate DU 140 will be described below.

[0071] When first network device 130 obtains the CSI resource set, first network device 130 may also obtain the CSI resource configuration set from candidate DU 140, and then send information 201 to second network device 110, and then send the information to terminal device 120. Since the L1 measurement is reported to source DU 110 rather than candidate DU 140, a reporting configuration for the candidate cell may be required so that source DU 110 can receive L1 measurements for the CSI resource set configured by candidate DU 140 from UE 120, and so that source DU 110 can also learn the specific cell identity with which the measurement is associated.

[0072] Therefore, in some embodiments, the CSI resource sets associated with candidate cells 141 to 144 may be included in a candidate cell configuration set, and each candidate cell configuration may include a CSI resource configuration set for one or more candidate cells and a CSI report configuration set for one or more candidate cells.

[0073] A candidate cell configuration is a configuration for each candidate cell 141, 142, 143, or 144 at a candidate DU 140 for LTM, and includes the cell ID of the candidate cell. Each candidate cell has one candidate cell configuration. One or more candidate cell configurations may exist at the same candidate DU 140 for UE 120, or multiple candidate cell configurations may exist at different candidate DUs 140 for UE 120. Each candidate cell configuration is identified by an index, which is referred to as a candidate cell configuration index, candidate configuration index, or other names.

[0074] The CSI-reporting configuration (ReportConfig) can be used to configure L1 measurement reports sent on the Physical Uplink Control Channel (PUCCH) on the cell in which the CSI-reporting configuration is included, or to configure L1 measurement reports sent on the Physical Uplink Shared Channel (PUSCH) on the cell in which the CSI-reporting configuration is included. The CSI-reporting configuration includes the CSI-resource used for channel measurement, the report number indicating the CSI-related quantity to be reported (e.g., CRI-RSRP, SSB-index-RSRP), the PUCCH for sending the L1 measurement report, etc.

[0075] For example, the candidate DU 140 summarizes the CSI-measurement configuration (MeasConfig) for each candidate cell, where the CSI-measurement configuration includes the CSI-resource configuration and the CSI-reporting configuration. In one example, the CSI-measurement configuration for the candidate cell is provided under the cell group configuration (CellGroupConfig) of the candidate cell. The CU 130 sends the CSI-reporting configuration of the serving cell to the candidate DU 140, based on which the candidate DU 140 summarizes the CSI-resource configuration of the candidate cell. For example, the L1 measurement report sent by the UE includes a candidate cell ID, which indicates the target cell to which the L1 measurement instance is related. For example, the candidate cell ID will be a PCI or a candidate configuration index, where each index is used to identify a candidate cell configuration.

[0076] In these embodiments, by configuring the reporting configuration for the candidate DU 140, even if the CSI resource set is configured by the candidate DU 140, the source DU 110 can receive a measurement report from the UE 120 via the PUCCH or PUSCH indicated or configured by the reporting configuration for the candidate DU 140. Further, since the measurement report sent by the UE 120 includes the candidate cell ID and the candidate cell ID can indicate the target cell to which the L1 measurement instance is related, based on the L1 measurement report, the source DU 110 can learn the specific target cell ID based on the L1 measurement report.

[0077] Therefore, when a configuration for L1 measurement reference signals is provided under the cell group configuration (CellGroupConfig) of each candidate cell, to support L1 measurement, candidate DU 140 summarizes the CSI-measurement configuration for each candidate cell, where the CSI-measurement configuration includes a CSI-resource configuration and a CSI-reporting configuration (i.e., the CSI-measurement configuration for each candidate cell is provided by candidate DU 140). CU 130 sends the CSI-reporting configuration of the serving cell to candidate DU 140, based on which candidate DU 140 summarizes the CSI-resource configuration of the candidate cell. Furthermore, the L1 measurement report sent by the UE includes a candidate cell identity, which indicates the target cell to which the L1 measurement instance relates.

[0078] The following describes how the candidate DU 140 determines CSI resources that are compatible with the UE capability of LTM L1 measurement.

[0079] The CSI resources for the candidate cells are provided by the candidate DU 140. The candidate cells may be within the same candidate DU 140 or different candidate DUs 140. If the candidate DU 140 provides CSI resources for each candidate cell and the number is unlimited, the CSI resource configuration for the UE will be too complex and the signaling overhead will be too large. For example, following the traditional CSI reporting framework, the maximum number of CSI resource sets per CSI resource configuration is 16, and the maximum number of CSI resources per CSI resource set is 64, resulting in a maximum number of CSI resources per cell of 1024. Considering LTM, if there are 8 candidate cells, the final number of CSI resources for the UE will be 8192.

[0080] For example, to reduce signaling overhead, CU 130 may determine a maximum number of CSI-resources to be provided for each candidate cell or each candidate DU 140, and send the maximum number to the candidate DU 140. Alternatively or additionally, CU 130 may determine a number of CSI-resources to be provided for each candidate cell or each candidate DU 140, and send the number to the candidate DU 140.

[0081] For example, if the candidate DU 140 receives the maximum number of CSI-resources to be provided for each candidate cell from the CU 130 , the candidate DU 140 thus prepares no more than the maximum number of CSI-resources for each candidate cell.

[0082] For example, if the candidate DU 140 receives the maximum number of CSI-resources to be provided for each candidate DU 140 (i.e., the maximum number of CSI-resources is for all candidate cells within the same candidate DU 140), the candidate DU 140 will determine the maximum number of CSI-resources for each candidate cell.

[0083] For example, CU 130 may first obtain the UE capabilities of LTM L1 measurement, and then CU 130 may determine the above-mentioned number or other parameters for CSI resources and send these parameters to candidate DU 140, which may then configure CSI resources for each candidate cell based on these parameters.

[0084] The UE capability may include at least one of the following: (1) an indicator indicating whether the UE supports CSI-RS-based L1 measurement of the candidate cell; (2) an indicator indicating whether the UE supports SSB-based L1 measurement of the candidate cell; (3) an indicator indicating whether the UE supports: a configuration of providing L1 measurement reference signals for the candidate cell under a serving cell configuration (ServingCellConfig) for the serving cell (that is, under the serving cell configuration for the serving cell, the CSI-resource configuration includes CSI-resources of both the serving cell and the candidate cell); (4) an indicator indicating whether the UE supports: a configuration of providing L1 measurement reference signals for the candidate cell independently of the serving cell configuration for the serving cell and the cell group configuration for the candidate cell; (5) an indicator indicating whether the UE supports: a configuration of providing L1 measurement reference signals for the candidate cell under a cell group configuration for the candidate cell, where each candidate cell has its own cell group configuration; (6) an indicator indicating whether the UE supports: a configuration of providing L1 measurement reference signals for the candidate cell under a cell group configuration for the candidate cell, where each candidate cell has its own cell group configuration; For example, to measure L1-RSRP (reference signal received power), the maximum total number of configured CSI-RS (e.g., NZP (non-zero power)-CSI-RS) resources and SSBs supported by the UE, where the maximum total number of configured CSI-RS and SSBs is used for the set of candidate cells, for each candidate cell, or for the group consisting of the serving cell and the candidate cells; (7) to perform L1 measurements (e.g., to measure L1-RSRP), the maximum total number of configured CSI-RS (e.g., NZP-CSI-RS) resources supported by the UE, where the maximum total number of configured CSI-RS resources is used for the set of candidate cells, for each candidate cell, or for the group consisting of the serving cell and the candidate cells; (8) the maximum number of periodic, aperiodic, or semi-persistent CSI report settings per BWP (bandwidth part) for CSI reporting or beam reporting; or (9) the number of CSI reports of reference signals that the UE can measure and process simultaneously (CSI reports include periodic, aperiodic, and semi-persistent CSI). CSI reports include bundle reports and CSI reports).

[0085] It should be noted that the parameters listed above are merely exemplary embodiments of UE capabilities, and the present disclosure is not limited thereto in any way.

[0086] By first obtaining the UE capabilities, the CU 130 can determine appropriate parameters for the candidate DUs 140 to configure CSI resources for L1 measurements, thereby reducing signaling overhead.

[0087] Therefore, to reduce signaling overhead and UE capabilities, the number of CSI-resources used for candidate cells should be limited. For example, CU 130 may obtain the UE capability for performing LTM L1 measurements; then, based at least on the UE capability, CU 130 may determine the maximum number of CSI-resources to be provided for each candidate cell or each candidate DU 140 and send this number to the candidate DU 140.

[0088] Example message flow

[0089] The following references Figure 3 A message flow 300 of a communication process according to some example embodiments of the present disclosure is described. In this embodiment, source DU 110 obtains CSI resources and corresponding candidate cell IDs from CU 130. Thereafter, source DU 110 summarizes a CSI resource configuration including CSI resources and corresponding candidate cell IDs for candidate cells 141 to 144, wherein the CSI resource configuration is transmitted to UE 120 via CU 130.

[0090] like Figure 3 As shown, at step 1 , when the CU 130 needs UE L1 measurement capability information, the CU 130 sends a UE capability query to the source DU 110 .

[0091] In one example, the UE capability query includes an indicator indicating the UE L1 measurement capability. The UE L1 measurement capability is the UE capability of L1 measurement on the candidate cell. The UE L1 measurement capability is named UE LTM L1 measurement capability, UE LTM capability, etc.

[0092] In another example, the UE L1 measurement capability may further include an L1 measurement capability filter. The L1 measurement capability filter is information that the CU 130 requests the UE 120 to filter UE capabilities. The L1 measurement capability filter includes at least one of the following: (a) a measurement type indicating the L1 measurement type, e.g., CSI-RS-based L1 measurement, SSB-based L1 measurement; (b) a configuration type indicating the configuration type of the L1 measurement reference signal for the candidate cell, e.g., under the serving cell configuration for the serving cell, independent of the serving cell configuration for the serving cell and the cell group configuration for the candidate cell, under the cell group configuration for the candidate cell; (c) the maximum total number of configured CSI-RS resources and SSBs supported by the UE for performing L1 measurement; (d) the maximum total number of configured CSI-RS resources supported by the UE for performing L1 measurement; (e) the maximum number of periodic, aperiodic, or semi-persistent CSI report settings per BWP for CSI reporting or beam reporting; and (f) the number of CSI reports for which the UE can simultaneously measure and process reference signals. CSI reports include periodic, aperiodic, and semi-persistent CSI. CSI reports include beam reports and CSI reports.

[0093] In another example, the UE capability query is included in the DL RRC messaging message.

[0094] like Figure 3 As shown, at step 2, the source DU 110 forwards the received UE capability query to the UE 120. At step 3, the UE 120 sends UE capability information to the source DU 110 to report the UE L1 measurement capability information.

[0095] In one example, the UE L1 measurement capability is included in the L1 measurement capability filter. The UE L1 measurement capability includes the following information: 1) an indicator indicating whether the UE supports CSI-RS-based L1 measurement of the candidate cell; 2) an indicator indicating whether the UE supports SSB-based L1 measurement of the candidate cell; 3) an indicator indicating whether the UE supports: providing a configuration of an L1 measurement reference signal for the candidate cell under the serving cell configuration for the serving cell (that is, under the serving cell configuration of the serving cell, the final CSI-resource configuration includes CSI-resources for both the serving cell and the candidate cell); 4) an indicator indicating whether the UE supports: independent of the serving cell configuration for the serving cell and the cell group configuration for the candidate cell , providing the configuration of the L1 measurement reference signal for the candidate cell; 5) an indicator indicating whether the UE supports: providing the configuration of the L1 measurement reference signal for the candidate cell under the cell group configuration for the candidate cell; 6) the maximum total number of configured CSI-RS resources and SSBs supported by the UE for performing L1 measurements; 7) the maximum total number of configured CSI-RS resources supported by the UE for performing L1 measurements; 8) the maximum number of periodic, aperiodic or semi-persistent CSI report settings per BWP for CSI reporting or beam reporting; and 9) the number of CSI reports that the UE can measure and process reference signals simultaneously. CSI reports include periodic, aperiodic and semi-persistent CSI. CSI reports include periodic, aperiodic and semi-persistent CSI. CSI reports include beam reports and CSI reports.

[0096] In another example, if the received UE capability query does not include an L1 measurement capability filter, the UE L1 measurement capability information includes one or more of the above information (1) to (9). In another example, the UE L1 measurement capability information includes one or more of the above information (1) to (9) corresponding to the L1 measurement capability filter included in the received UE capability query. For example, if the configuration type is included in the L1 measurement capability filter, the UE 120 reports the configuration type of the L1 measurement reference signal for the candidate cell supported by the UE, for example, under the serving cell configuration for the serving cell. In another example, the UE capability query is included in the DL RRC messaging message.

[0097] like Figure 3 As shown, at step 4, source DU 110 forwards the received UE capability query to CU 130. It should be noted that steps 1 to 4 are optional. If CU 130 has UE L1 measurement capability information, steps 1 to 4 are not required.

[0098] like Figure 3As shown, at step 5, the CU 130 determines the number of CSI-resources to be provided for each candidate cell or each candidate DU 140 or the maximum number of CSI resources.

[0099] In one example, CU 130 determines the number of CSI-resources for each candidate cell (e.g., cell 141, 142, 143, or 144). Thus, candidate DU 140 should prepare CSI-resources for candidate cell 141, 142, 143, or 144. It should be noted that the number of CSI-resources for one candidate cell may be different from the number of CSI-resources for another candidate cell.

[0100] In another example, CU 130 determines the maximum number of CSI-resources for each candidate cell. Thus, candidate DU 140 should prepare CSI-resources for no more than the maximum number of candidate cells. It should be noted that the maximum number of CSI-resources for one candidate cell may be different from the maximum number of CSI-resources for another candidate cell.

[0101] In another example, CU 130 determines the number of CSI-resources for each candidate cell DU 140. Thus, candidate DU 140 should prepare CSI-resources for each candidate cell (e.g., cell 141, 142, 143, or 144) belonging to candidate DU 140, and the total number of CSI-resources for the candidate cells belonging to the candidate DU should be equal to the number of CSI-resources for the candidate DU. It should be noted that the number of CSI-resources for one candidate cell DU may be different from the number of CSI-resources for another candidate DU.

[0102] In another example, CU 130 determines the maximum number of CSI resources for each candidate DU 140. Thus, candidate DU 140 should prepare CSI resources for each candidate cell belonging to candidate DU 140, and the total number of CSI resources for candidate cells belonging to the candidate DU should not exceed the maximum number. It should be noted that the maximum number of CSI resources for one candidate cell DU may be different from the maximum number of CSI resources for another candidate DU.

[0103] In another example, based on the UE L1 measurement capability information, the CU 130 determines the number of CSI-resources to be provided for each candidate cell or each candidate DU 140, or the maximum number of CSI-resources. In another example, the number of CSI-resources to be provided for each candidate cell or each candidate DU 140, or the maximum number of CSI-resources, depends on the implementation of the CU, for example, based on historical L1 measurement results.

[0104] like Figure 3 As shown, at step 6, by sending a UE context setup request (CONTEXT SETUP REQUEST) message including the candidate cell IDs to the candidate DU(s) 140, the CU 130 requests the preparation of the candidate cells in the candidate DU(s) 140 to create a UE context and establish one or more data bearers. It should be noted that the candidate cells belong to the same candidate DU or different candidate DUs. The candidate cell ID may be the PCI and / or CGI of the candidate cell. The UE context setup request message may also include the number of CSI-resources or the maximum number of CSI-resources to be provided for each candidate cell or each candidate DU. In one example, the number of CSI-resources or the maximum number of CSI-resources to be provided for each candidate cell or each candidate DU is included in the CU to DU RRC information IE in the UE context setup request message.

[0105] In another example, a UE context setup request message is sent for each candidate cell. That is, CU 130 sends multiple UE context setup request messages, where each UE context setup request message includes a candidate cell ID. The UE context setup request message may also include the number of CSI resources to be provided for the candidate cell, or the maximum number of CSI resources.

[0106] In another example, the UE context setup request message includes multiple candidate cell IDs (e.g., a list of candidate cell IDs) to the candidate DU, where the multiple candidate cells are within the same candidate DU. The UE context setup request message may also include the number of CSI-resources to be provided for each candidate cell or candidate DU, or the maximum number of CSI-resources.

[0107] like Figure 3 As shown, at step 7, if the preparation request is accepted, the candidate DU 140 responds to the CU 130 using a UE context setup response (CONTEXT SETUP RESPONSE) message. The UE context setup response message includes the candidate cell ID(s) requested from the CU and the candidate cell configuration. In one example, the candidate cell configuration includes lower layer configurations for the candidate cells, such as a cell group configuration, which includes a MAC entity, a logical channel set with an associated RLC entity, a primary cell, and one or more secondary cells.

[0108] The UE Context Setup Response message also includes the CSI-resources for the candidate cells. The number of CSI-resources for the candidate cells shall be equal to the number of CSI-resources for the candidate cells received in the UE Context Setup Request message, or not greater than the maximum number of CSI-resources for the candidate cells received in the UE Context Setup Request message. If the number of CSI-resources or the maximum number of CSI-resources is used for the candidate DU received in the UE Context Setup Request message, the total number of CSI-resources for all candidate cells within the candidate DU shall be equal to the number of CSI-resources for the candidate DU, or not greater than the maximum number of CSI-resources for the candidate DU.

[0109] In one example, the CSI-resource for the candidate cell is included in the DU to CU RRC Information IE in the UE Context Setup Response message. In another example, a UE Context Setup Response message is sent for each requested candidate cell. In another example, the UE Context Setup Response message includes multiple candidate cell configurations, where each candidate cell configuration is for a candidate cell.

[0110] like Figure 3 As shown, at step 8, CU 130 sends a UE context modification request (CONTEXT MODIFICATION REQUEST) message including the candidate cell configuration to source DU 110 to modify the UE context. The UE context modification request message includes the CSI-resources for the candidate cell received in step 7. Each CSI-resource should be associated with a candidate cell ID, which indicates which candidate cell the CSI-resource is for. The candidate cell ID can be a PCI, CGI, or candidate configuration index, where each index is also used to identify the candidate cell configuration.

[0111] In one example, the CSI-resources for the candidate cells are included in the CU to DU RRC Information IE in the UE Context Modification Request message. In another example, a UE Context Modification Request message is sent for each candidate cell. In another example, the UE Context Modification Request message includes CSI-resources for multiple candidate cells.

[0112] like Figure 3As shown, at step 9, if the request is accepted, the source DU 110 responds to the CU 130 using a CONTEXT MODIFICATION RESPONSE message. The UE CONTEXT MODIFICATION RESPONSE message also includes the CSI-resource configuration for L1 measurement. The source DU 110 summarizes the CSI resource configuration, which includes the CSI-resources of the candidate cells (e.g., under the serving cell configuration for the serving cell). The CSI-resource configuration includes the CSI-resources for the serving cell and the CSI-resources for the candidate cells. Each CSI-resource should be associated with a serving cell ID or a candidate cell ID. For example, Figure 2B As shown, the CSI-resource configuration method is provided.

[0113] like Figure 2B As shown, CSI-resource #0 is a CSI resource for the serving cell (e.g., cell 111 with PCI #0), CSI-resource #1 is a CSI resource for a candidate cell (e.g., cell 141 with PCI #1), CSI-resource #2 is a CSI resource for a candidate cell (e.g., cell 142 with PCI #2), and CSI-resource #3 is a CSI resource for a candidate cell (e.g., cell 143 with PCI #3). Since each CSI resource in the CSI resource configuration corresponds to a corresponding candidate cell and the source DU 110 is aware of the CSI resource configuration, when the source DU 110 receives a CSI resource measurement report, the source DU 110 can determine the measurement for the corresponding CSI resource to be associated with a specific candidate cell. That is, the source DU 110 can determine the target cell ID based on the L1 measurement report.

[0114] In one example, the CSI-resource configuration is included in the DU to CU RRC Information IE in the UE Context Modification Response message. In another example, a UE Context Modification Response message is sent for each requested candidate cell. In another example, the UE Context Modification Response message includes the CSI-resource configuration for the serving cell and multiple candidate cells.

[0115] like Figure 3As shown, at step 10, CU 130 sends a DL RRC message transfer message to source DU 110, and the DL RRC message transfer message includes the generated RRC reconfiguration message. The RRC reconfiguration message includes the CSI-resource configuration for the serving cell and one or more candidate cells. The RRC reconfiguration message may also include an indicator that instructs UE 120 to maintain the CSI-resource configuration for the serving cell and one or more candidate cells after cell switching. It should be noted that CU 130 can send the RRC reconfiguration message to source DU 110 via other messages (e.g., UE context modification request message). It should be noted that CU 130 can send the CSI-resource configuration for the serving cell and one or more candidate cells to candidate DU 140 via UE context modification request message or other messages, wherein the message may also include an indicator that instructs candidate DU 140 to maintain the CSI-resource configuration for one or more candidate cells after cell switching.

[0116] like Figure 3 As shown, at step 11, the source DU 110 forwards the RRC reconfiguration message to the UE 120. Figure 3 As shown, at step 12, UE 120 responds to source DU 110 using an RRC Reconfiguration Complete message. Figure 3 As shown, at step 13, source DU 110 forwards the RRC reconfiguration complete message to CU 130 via UL RRC messaging. It should be noted that CU 110 may forward the RRC reconfiguration complete message to CU 130 via other messages (eg, UE context modification request message).

[0117] like Figure 3 As shown, at step 14, UE 120 starts reporting L1 measurements of candidate cells to source DU 110. Figure 3 As shown, at step 15, the source DU 110 determines that an LTM cell handover to a candidate cell is required.

[0118] The L1 measurement report includes SSBRI#k corresponding to the (k+1)th entry in the corresponding CSI-SSB-resource list in the corresponding CSI-SSB-resource set, or CRI#k corresponding to the (k+1)th configured entry of the corresponding NZP-CSI-RS resource in the corresponding NZP-CSI-RS-resource list. Based on the CSI-resource configuration in step 9, the source DU 110 determines a candidate cell corresponding to SSBRI#k or CRI#k.

[0119] like Figure 3As shown, at step 16, the source DU 110 sends an LTM cell switching command (e.g., MACCE) to the UE 120 to trigger the UE 120 to change from the current serving cell to the selected candidate cell. The LTM cell switching command (e.g., MACCE) may also include an indicator that instructs the UE 120 to maintain the CSI-resource configuration for the serving cell and one or more candidate cells after the cell switching. Figure 3 As shown, at step 17, an access procedure is performed between the UE 120 and the candidate DU 140.

[0120] The following references Figure 4A A message flow 400 of a communication process according to some example embodiments of the present disclosure is described. In this embodiment, CU 130 obtains CSI resources and corresponding candidate cell IDs from candidate DU 140 and summarizes the CSI resource configuration. CU 130 then sends the final CSI resource configuration to UE 120. CU 130 also sends the CSI resource configuration to source DU 110. The CSI resource configuration includes the CSI resources of the candidate cells and the corresponding candidate cell IDs.

[0121] like Figure 4A As shown, steps 1 to 7 are the same as those in the reference Figure 3 Steps 1 to 7 described are essentially the same, so for the sake of brevity, they will be omitted. Figure 4A It should be noted that steps 1 to 4 are optional. If the CU 130 has the UE L1 measurement capability information, steps 1 to 4 are not required.

[0122] like Figure 4A As shown, at step 8, CU 130 summarizes the CSI-resource configuration including the CSI-resources of the candidate cells, e.g., independently of the serving cell configuration for the serving cell and the cell group configuration for the candidate cells. Each CSI-resource for a candidate cell should be associated with a candidate cell ID (e.g., PCI, CGI, or candidate configuration index).

[0123] In one example, if Figure 4B As shown, the CSI-resource configuration method is provided. In another example, as Figure 4C As shown, the CSI-resource configuration method is provided. Figure 4B In the example shown, there are no CSI resources for the serving cell, but Figure 4C In the example shown, there are CSI resources for the serving cell, so that UE 120 can perform measurements on the CSI resources configured for the serving cell. Figure 4B and Figure 4CIn the CSI resource configuration shown, CSI resources are configured for multiple candidate DUs, even for the serving cell of the source DU 110.

[0124] like Figure 4A As shown, at step 9, CU 130 sends a DL RRC messaging message to source DU 110. The DL RRC messaging message includes the generated RRC reconfiguration message. The RRC reconfiguration message includes the CSI-resource configuration for one or more candidate cells. The RRC reconfiguration message may also include an indicator that instructs the UE to maintain the CSI-resource configuration for one or more candidate cells after cell switching. The DL RRC messaging message also includes the CSI-resource configuration for one or more candidate cells, which is to be used by the source DU 110. The DL RRC messaging message may also include an indicator that instructs the source DU 110 to maintain the CSI-resource configuration for one or more candidate cells after cell switching. It should be noted that CU 130 can send the RRC reconfiguration message and the CSI-resource configuration for the candidate cell to the source DU 110 via other messages (e.g., a UE context modification request message). It should be noted that CU 130 may send the CSI-resource configuration for one or more candidate cells to candidate DU 140 via a UE context modification request message or other message, wherein the message may also include an indicator instructing candidate DU 140 to maintain the CSI-resource configuration for one or more candidate cells after cell switching.

[0125] like Figure 4A As shown, at step 10 , the source DU 110 stores the CSI-resource configuration for the candidate cell and forwards the CSI-reconfiguration message to the UE 120 .

[0126] like Figure 4A As shown, steps 11 to 16 are the same as those in the reference Figure 3 Steps 12 to 17 described are essentially the same, so for the sake of brevity, they will be omitted. Figure 4A A description of steps 11 to 16.

[0127] The following references Figure 5A A message flow 500 of a communication process according to some example embodiments of the present disclosure is described. For example, the candidate DU 140 summarizes the CSI-measurement configuration for each candidate cell, where the CSI-measurement configuration includes a CSI-resource configuration and a CSI-reporting configuration.

[0128] like Figure 5A As shown, steps 1 to 5 are the same as those in the reference Figure 3 Steps 1 to 5 described are essentially the same, so for the sake of brevity, they will be omitted. Figure 5A It should be noted that steps 1 to 4 are optional. If the CU 130 has the UE L1 measurement capability information, steps 1 to 4 are not required.

[0129] like Figure 5A As shown, at step 6, CU 130 sends a UE context setup request message including a candidate cell ID to candidate DU(s) 140, requesting the preparation of candidate cells in the candidate DU(s) 140 to create a UE context and establish one or more data bearers. It should be noted that the candidate cells may be in the same candidate DU or in different candidate DUs. The candidate cell ID may be the PCI and / or CGI of the candidate cell.

[0130] The UE context setup request message also includes the CSI-report configuration for the candidate cell. The CSI-report configuration may include at least one of the following: (1) Report quantity: indicating the CSI-related quantity to be reported, such as CRI-RSRP, SSB-index-RSRP; and (2) PUCCH-CSI-resource: indicating the resource to send the L1 measurement report when sending the L1 measurement report on the serving cell.

[0131] The UE context setup request message may also include the number of CSI-resources to be provided for each candidate cell or each candidate DU or the maximum number of CSI resources. In one example, the number of CSI-resources to be provided for each candidate cell or each candidate DU or the maximum number of CSI-resources is included in the CU to DU RRC Information IE in the UE context setup request message.

[0132] In another example, a UE context setup request message is sent for each candidate cell. That is, CU 130 sends multiple UE context setup request messages, where each UE context setup request message includes a candidate cell ID. The UE context setup request message may also include the number of CSI resources to be provided for the candidate cell, or the maximum number of CSI resources.

[0133] In another example, the UE context setup request message includes multiple candidate cell IDs (e.g., a list of candidate cell IDs) to the candidate DU, where the multiple candidate cells are within the same candidate DU. The UE context setup request message may also include the number of CSI-resources to be provided for each candidate cell or candidate DU, or the maximum number of CSI-resources.

[0134] like Figure 5AAs shown, at step 7, if the preparation request is accepted, the candidate DU responds to the CU using a UE context setup response message. The UE context setup response message includes the (multiple) candidate cell IDs requested from the CU, and the candidate cell configuration. The candidate cell configuration includes a lower layer configuration for the candidate cell, for example, a cell group configuration, which contains a MAC entity, a logical channel set with an associated RLC (radio link control) entity, a primary cell, and one or more secondary cells. The UE context setup response message also includes a CSI-measurement configuration for the candidate cell. The CSI-measurement configuration includes a CSI-resource configuration and a CSI-report configuration for the candidate cell, wherein the CSI-report configuration is received in step 6.

[0135] The number of CSI-resources for candidate cells shall be equal to the number of CSI-resources for candidate cells received in the UE CONTEXT SETUP REQUEST message, or not greater than the maximum number of CSI-resources for candidate cells received in the UE CONTEXT SETUP REQUEST message. If the number of CSI-resources or the maximum number of CSI-resources is used for a candidate DU received in the UE CONTEXT SETUP REQUEST message, the total number of CSI-resources for all candidate cells within the candidate DU shall be equal to the number of CSI-resources for the candidate DU, or not greater than the maximum number of CSI-resources for the candidate DU.

[0136] For example, Figure 5B As shown, the CSI-resource configuration method is provided. Figure 5B As shown, CSI resources are configured for each candidate cell within candidate DU 1 (e.g., candidate DU 140). CSI resources are not configured for another candidate DU. In other words, CSI resources are configured for the cell group in one candidate DU.

[0137] In one example, if Figure 5B As shown, under the cell group configuration of the candidate cells, a CSI-measurement configuration for the candidate cells is provided. In another example, a UE context setup request message is sent for each requested candidate cell. In another example, a UE context setup response message includes multiple candidate cell configurations, where each candidate cell configuration is for a candidate cell.

[0138] like Figure 5AAs shown, at step 8, CU 130 sends a DL RRC message transfer message to source DU 110, which includes the generated RRC reconfiguration message. The RRC reconfiguration message includes the CSI-measurement configuration for (multiple) candidate cells. The RRC reconfiguration message may also include an indicator that instructs the UE to maintain the CSI-resource configuration for one or more candidate cells after cell switching. It should be noted that CU 130 can send the RRC reconfiguration message to source DU 110 via other messages (e.g., UE context modification request message).

[0139] like Figure 5A As shown, steps 9 to 11, 14 and 15 are the same as those in reference Figure 3 The steps 11 to 13, 16 and 17 described are essentially the same, so for the sake of brevity, they will be omitted. Figure 5A Description of steps 9 to 11, 14, and 15.

[0140] like Figure 5A As shown, at step 12, UE 120 begins reporting L1 measurements of candidate cells to source DU 110. The L1 measurement report sent by the UE includes a candidate cell ID, which indicates the candidate cell to which the L1 measurement instance relates. The candidate cell ID can be a PCI or a candidate configuration index, where each index is used to identify a candidate cell configuration.

[0141] like Figure 5A As shown, at step 13, the source DU 110 determines that an LTM cell handover to a candidate cell is required. Since the L1 measurement report sent by the UE includes the candidate cell ID, the source DU 110 determines which candidate cell should be selected as the target cell for the LTM cell handover based on the L1 measurement report.

[0142] The following references Figure 6 A message flow 600 of a communication process according to some example embodiments of the present disclosure is described. In this embodiment, the L1 measurement report sent by the UE includes a candidate cell ID, which indicates the candidate cell to which the L1 measurement instance relates. The candidate cell ID may be a PCI or a candidate configuration index, where each index is used to identify a candidate cell configuration.

[0143] like Figure 6 As shown, at step 1, CU 130 determines the CSI-measurement configuration for the candidate cell. In one example, the CU determines the CSI-measurement configuration for the candidate cell as shown in FIG. Figure 3The CSI-measurement configuration for the candidate cell is obtained in the manner shown. In this case, the CSI-measurement configuration includes CSI-resources for the serving cell and the candidate cell. Each CSI-resource for the candidate cell should be associated with the candidate cell ID. Each CSI-resource for the serving cell should be associated with the serving cell ID.

[0144] In another example, CU is Figure 4A The CSI-measurement configuration for a candidate cell is obtained in the manner shown. In this case, each CSI-resource for a candidate cell should be associated with a candidate cell ID.

[0145] In another example, CU is Figure 5A The CSI-measurement configuration for a candidate cell is obtained in the manner shown. In this case, each CSI-resource for a candidate cell should be associated with a candidate cell ID.

[0146] like Figure 6 As shown, at step 2, the CU 130 sends a DL RRC message transfer message to the source DU 110, and the DL RRC message transfer message includes the generated RRC reconfiguration message. The RRC reconfiguration message includes the CSI-measurement configuration for one or more candidate cells. The RRC reconfiguration message may also include an indicator that instructs the UE to maintain the CSI-resource configuration for one or more candidate cells after the cell switch. It should be noted that the CU can send the RRC reconfiguration message to the source DU 110 via other messages (e.g., a UE context modification request message). It should be noted that the CU 130 can send the CSI-resource configuration for one or more candidate cells to the candidate DU 140 via a UE context modification request message or other message, wherein the message may also include an indicator that instructs the candidate DU 140 to maintain the CSI-resource configuration for one or more candidate cells after the cell switch.

[0147] like Figure 6 As shown, at step 3, the source DU 110 forwards the RRC reconfiguration message to the UE. Figure 6 As shown, at step 4, UE 120 responds to source DU 110 with an RRC reconfiguration complete message. Figure 6 As shown, at step 5, the source DU 110 forwards the RRC Reconfiguration Complete message to the CU via a UL RRC Messaging message. It should be noted that the source DU 110 may forward the RRC Reconfiguration Complete message to the CU via other messages (eg, a UE Context Modification Response message).

[0148] like Figure 6As shown, at step 6, UE 120 begins reporting L1 measurements of candidate cells to source DU 110. The L1 measurement report sent by UE 120 includes a candidate cell ID, which indicates the candidate cell to which the L1 measurement instance relates. The candidate cell ID can be a PCI or a candidate configuration index, where each index is used to identify a candidate cell configuration.

[0149] like Figure 6 As shown, at step 7, the source DU 110 determines that an LTM cell handover to a candidate cell is required. Since the L1 measurement report sent by the UE includes the candidate cell ID, the source DU 110 determines which candidate cell should be selected as the target cell for the LTM cell handover based on the L1 measurement report.

[0150] like Figure 6 As shown, at step 8, the source DU 110 sends an LTM cell switching command to the UE 120 to trigger the UE 120 to change from the current serving cell to the selected candidate cell. The LTM cell switching command (e.g., MAC CE) may also include an indicator that instructs the UE 120 to maintain the CSI-resource configuration for one or more candidate cells after the cell switching. Figure 6 As shown, at step 9, an access procedure is performed between the UE 120 and the candidate DU 140.

[0151] Example Method

[0152] Figure 7 A flow chart of an example method 700 for communication according to some embodiments of the present disclosure is illustrated. In some embodiments, the method 700 may be performed on a device in a communication network (such as a first network device, such as a Figure 1C Additionally or alternatively, the method 700 may be implemented at the CU 130 shown. Figure 1C In some other embodiments, the method 700 may be implemented at other devices shown. Figure 1C Further, it should be understood that the method 700 may include additional blocks not shown and / or may omit some of the blocks shown, and the scope of the present disclosure is not limited in this regard. For discussion purposes, reference is made to Figure 1C Method 700 is described from the perspective of first network device 130 .

[0153] At block 710, the first network device 130 obtains a set of CSI resources associated with one or more candidate cells 141 to 144 for at least one L1 measurement, wherein the set of CSI resources is to be used by the terminal device 120 to perform the at least one L1 measurement. At block 720, the first network device 130 transmits information indicating the set of CSI resources to the second network device 110 serving the terminal device 120 via a transceiver.

[0154] In some embodiments, first network device 130 determines a CSI resource configuration set based on the obtained CSI resource set, the CSI resource configuration set including the CSI resource set and one or more corresponding identities of one or more candidate cells, and then sends the CSI resource configuration set indicating the CSI resource set to second network device 110. In some embodiments, first network device 130 receives a CSI resource configuration set from second network device 110, the CSI resource configuration set including the CSI resource set and one or more corresponding identities of one or more candidate cells, wherein the CSI resource configuration set is determined by second network device 110 based on the received CSI resource set.

[0155] In some embodiments, first network device 130 receives a candidate cell configuration set indicating CSI resource sets for one or more candidate cells provided by third network device 140. In some embodiments, the candidate cell configuration set includes a CSI resource configuration set for the one or more candidate cells and a CSI reporting configuration set for the one or more candidate cells. In some embodiments, first network device 130 further sends a CSI reporting configuration for a second network device to third network device 140, wherein the CSI reporting configuration set for the one or more candidate cells is determined based on the CSI reporting configuration for second network device 110. In some embodiments, the CSI reporting configuration of the CSI reporting configuration set for the one or more candidate cells includes one of: a report quantity indicating a CSI-related quantity to be reported, or an uplink transmit CSI resource indicating resources for transmitting an L1 measurement report to the second network device.

[0156] In some embodiments, the first network device 130 sends a CSI resource configuration set indicating a CSI resource set to the terminal device via the second network device. In some embodiments, the first network device 130 sends a CSI report configuration set for one or more candidate cells to the terminal device 120 via the second network device 110.

[0157] In some embodiments, the first network device 130 sends a CSI resource configuration set to the third network device, where the CSI resource configuration set includes a CSI resource set and one or more corresponding identities of one or more candidate cells.

[0158] In some embodiments, the first network device 130 determines a maximum number of CSI resources in a CSI resource set to be provided for a candidate cell, which is a candidate cell among one or more candidate cells provided by the third network device; and then sends, to the third network device, a maximum number of CSI resources used to determine a CSI resource set associated with the one or more candidate cells.

[0159] In some embodiments, the first network device 130 determines the number of CSI resources in a CSI resource set to be provided for a candidate cell, which is a candidate cell among one or more candidate cells provided by the third network device; and then sends a message to the third network device for determining the number of CSI resource sets associated with the one or more candidate cells.

[0160] In some embodiments, the first network device 130 determines an identity (ID) of one or more candidate cells; and sends the ID to the third network device for use in determining a set of CSI resources associated with the one or more candidate cells.

[0161] In some embodiments, the identity of the candidate cell comprises a PCI, a CGI, or a candidate configuration index, where the index is used to identify a candidate configuration for the candidate cell.

[0162] In some embodiments, the first network device 130 obtains the L1 measurement capability of the terminal device from the terminal device. In some embodiments, the L1 measurement capability of the terminal device includes one of the following: an indicator for indicating whether the terminal device supports CSI-RS-based L1 measurement of one of the one or more candidate cells; an indicator for indicating whether the terminal device supports SSB-based L1 measurement of one of the one or more candidate cells; an indicator for indicating whether the terminal device supports CSI resource configuration to be also associated with a second network device; an indicator for indicating whether the terminal device supports providing CSI resource configuration independently of the serving cell or the candidate cell; an indicator for indicating whether the terminal device supports CSI resource configuration to be associated with a group of one or more candidate cells; the maximum total number of configured CSI-RS resources and SSBs supported by the terminal device for performing L1 measurement; the maximum total number of configured CSI-RS resources supported by the terminal device for performing L1 measurement; the maximum number of periodic or non-periodic or semi-persistent CSI report settings per bandwidth part (BWP) for CSI reporting or beam reporting; or the number of CSI reports of reference signals that the terminal device can measure and process simultaneously.

[0163] In some embodiments, the first network device 130 sends one or more configurations indicating a CSI resource set to a third network device 140 that provides one of the one or more candidate cells. In some embodiments, the first network device 130 sends an indicator to the terminal device 120 via the second network device 120, instructing the terminal device to maintain the CSI resource configuration set after the cell handover, the CSI resource configuration set including the CSI resource set and one or more corresponding identities of the one or more candidate cells.

[0164] Figure 8 A flow chart of an example method 800 for communication according to some embodiments of the present disclosure is illustrated. In some embodiments, the method 800 may be performed on a device in a communication network (such as a second network device, such as a Figure 1C Additionally or alternatively, the method 800 may be implemented at the CU 110 shown. Figure 1C In some other embodiments, the method 800 may be implemented at other devices shown. Figure 1C Further, it should be understood that the method 800 may include additional blocks not shown and / or may omit some of the blocks shown, and the scope of the present disclosure is not limited in this regard. For discussion purposes, reference is made to Figure 1C The method 800 is described from the perspective of the second network device 110 .

[0165] At block 810, the second network device 110 obtains a set of CSI resources associated with one or more candidate cells for at least one L1 measurement, wherein the set of CSI resources is to be used by the terminal device to perform the at least one L1 measurement. At block 820, the second network device 110 sends information indicating the set of CSI resources to the terminal device. At block 830, the second network device 110 obtains at least one L1 measurement report.

[0166] In some embodiments, at least one L1 measurement report is obtained from the terminal device 120. In some embodiments, at least one L1 measurement report is obtained from the first network device 130.

[0167] In some embodiments, a CSI resource set is obtained from a first network device 130, which is used to obtain a CSI resource set from one or more candidate cells 141 to 144; the second network device 110 determines a CSI resource configuration set based on the obtained CSI resource set; and sends a CSI resource configuration set indicating the CSI resource set to the terminal device 120.

[0168] In some embodiments, the second network device 110 receives a CSI resource configuration set indicating a CSI resource set from the first network device 130 for obtaining a CSI resource set associated with one or more candidate cells; and sends the CSI resource configuration set indicating the CSI resource set to the terminal device 120.

[0169] In some embodiments, the second network device selects the target cell from the one or more candidate cells based on the at least one L1 measurement report.

[0170] Figure 9 A flow chart illustrating an example method 900 for communication according to some embodiments of the present disclosure is shown. In some embodiments, the method 900 may be performed by a device (such as a Figure 1C Additionally or alternatively, the method 900 may be implemented at a terminal device as shown. Figure 1C In some other embodiments, the method 900 may be implemented at other devices shown. Figure 1C Further, it should be understood that the method 900 may include additional blocks not shown and / or may omit some of the blocks shown, and the scope of the present disclosure is not limited in this regard. For discussion purposes, reference is made to Figure 1C The method 900 is described from the perspective of the terminal device 120 .

[0171] At block 910, the terminal device 120 receives information indicating a set of CSI resources associated with one or more candidate cells 141 to 144 for at least one L1 measurement from the second network device 110. At block 920, the terminal device 120 performs at least one L1 measurement on the set of CSI resources. At block 930, the terminal device 120 sends at least one L1 measurement report.

[0172] In some embodiments, the terminal device 120 receives a CSI resource configuration set indicating a CSI resource set from the second network device 110 ; and sends at least one L1 measurement result for one or more candidate cells to the second network device 110 .

[0173] In some embodiments, the terminal device 120 receives an indicator from the second network device 120, the indicator instructing the terminal device to maintain a CSI resource configuration set after cell switching, the CSI resource configuration set comprising a CSI resource set and one or more corresponding identities of one or more candidate cells.

[0174] In some embodiments, the terminal device 120 receives a CSI report configuration set for one or more candidate cells and a CSI resource configuration set indicating a CSI resource set for one or more candidate cells from the second network device 110, and sends at least one L1 measurement result for one or more candidate cells and at least one identity of the corresponding one or more candidate cells to the second network device.

[0175] In some embodiments, at least one L1 measurement report is sent to the third network device 140 providing one or more candidate cells.

[0176] Example device

[0177] Figure 10 A simplified block diagram of a device 1000 suitable for implementing various embodiments of the present disclosure is shown. The device 1000 can be considered as Figure 1C Another example implementation of the terminal device 120 and the network devices 110, 130, and 140 is shown. Thus, the device 1000 may be implemented at or as at least a portion of the terminal device 120 and the network devices 110, 130, and 140.

[0178] As shown, the device 1000 includes a processor 1010, a memory 1020 coupled to the processor 1010, a suitable transmitter (TX) and receiver (RX) 1040 coupled to the processor 1010, and a communication interface coupled to the TX / RX 1040. The memory 1010 stores at least a portion of a program 1030. The TX / RX 1040 is used for bidirectional communication. The TX / RX 1040 has at least one antenna to facilitate communication, but in practice, the access nodes mentioned in this disclosure may have several antennas. The communication interface may represent any interface required for communication with other network elements, such as an X2 interface for bidirectional communication between eNBs, an S1 interface for communication between a Mobility Management Entity (MME) / Serving Gateway (S-GW) and an eNB, a Un interface for communication between an eNB and a relay node (RN), or a Uu interface for communication between an eNB and a terminal device.

[0179] Assume that the program 1030 includes program instructions that, when executed by the associated processor 1010, enable the device 1000 to operate in accordance with various embodiments of the present disclosure, as described herein with reference to FIG. Figure 9 The embodiments herein may be implemented by computer software executable by the processor 1010 of the device 1000, or by hardware, or by a combination of software and hardware. The processor 1010 may be configured to implement various embodiments of the present invention. Furthermore, the combination of the processor 1010 and the memory 1020 may form a processing component 1050 adapted to implement various embodiments of the present disclosure.

[0180] Memory 1020 may be of any type suitable for the local technology network and may be implemented using any suitable data storage technology (such as, by way of non-limiting examples, non-transitory computer-readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory). Although only one memory 1020 is shown in device 1000, several physically distinct memory modules may be present in device 1000. Processor 1010 may be of any type suitable for the local technology network and may include, by way of non-limiting examples, one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. The device 1000 may have multiple processors, such as application-specific integrated circuit chips that are time-slave to a clock that synchronizes a master processor.

[0181] In some embodiments, an apparatus capable of executing method 700 (e.g., first network device 130), method 800 (e.g., second network device 110), and method 900 (e.g., terminal device 120) may include components for executing the corresponding steps of methods 700, 800, and 900. These components may be implemented in any suitable form. For example, these components may be implemented in a circuit system or a software module. In some embodiments, these components include at least one processor and at least one memory including computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, cause the execution of methods 700, 800, and 900.

[0182] These embodiments may also be described using the following terms:

[0183] Clause 1. A first network device comprising a processor and a transceiver, the transceiver being coupled to the processor, wherein the processor is configured to: obtain a set of channel state information (CSI) resources associated with one or more candidate cells for at least one layer 1 (L1) measurement, wherein the set of CSI resources is to be used by a terminal device to perform the at least one L1 measurement; and send, via the transceiver, information indicating the set of CSI resources to a second network device serving the terminal device.

[0184] Clause 2. A first network device according to clause 1, wherein the processor is further configured to: determine a CSI resource configuration set based on the obtained CSI resource set, the CSI resource configuration set including the CSI resource set and one or more corresponding identities of the one or more candidate cells, and wherein sending the information to the second network device includes: sending the CSI resource configuration set indicating the CSI resource set to the second network device.

[0185] Clause 3. A first network device according to clause 1, wherein the processor is further configured to: receive a CSI resource configuration set from the second network device, the CSI resource configuration set comprising the CSI resource set and one or more corresponding identities of the one or more candidate cells, wherein the CSI resource configuration set is determined by the second network device based on the received CSI resource set.

[0186] Clause 4. The first network device of clause 1, wherein obtaining the CSI resource set associated with the one or more candidate cells comprises: receiving, from the one or more candidate cells provided by a third network device, a candidate cell configuration set indicating the CSI resource set for the one or more candidate cells.

[0187] Clause 5. The first network device of Clause 4, wherein the candidate cell configuration set comprises: a CSI resource configuration set for the one or more candidate cells, and a CSI reporting configuration set for the one or more candidate cells.

[0188] Clause 6. A first network device according to clause 5, wherein the processor is further configured to: send a CSI reporting configuration for the second network device to the third network device, wherein the CSI reporting configuration set for the one or more candidate cells is determined based on the CSI reporting configuration for the second network device.

[0189] Clause 7. A first network device according to clause 5 or 6, wherein the CSI reporting configuration of the CSI reporting configuration set for the one or more candidate cells includes one of the following: a report number indicating a CSI-related number to be reported, or an uplink transmit CSI resource indicating resources for sending L1 measurement reports to the second network device.

[0190] Clause 8. The first network device of clause 2, 3 or 5, wherein the first network device is further configured to: send the CSI resource configuration set indicating the CSI resource set to the terminal device via the second network device.

[0191] Clause 9. The first network device of clause 5, wherein the processor is further configured to: send the CSI reporting configuration set for the one or more candidate cells to the terminal device via the second network device.

[0192] Clause 10. A first network device according to any one of clauses 1 to 9, wherein the processor is further configured to: determine a maximum number of the CSI resources in the CSI resource set to be provided for a candidate cell, the candidate cell being a candidate cell in the one or more candidate cells provided by the third network device; and then, send to the third network device a maximum number of the CSI resource sets used to determine the maximum number associated with the one or more candidate cells.

[0193] Clause 11. A first network device according to any one of clauses 1 to 9, wherein the processor is further configured to: determine the number of the CSI resources in the CSI resource set to be provided for a candidate cell, the candidate cell being a candidate cell among the one or more candidate cells provided by the third network device; and then, send to the third network device a number of the CSI resource sets used to determine the number of the CSI resource sets associated with the one or more candidate cells.

[0194] Clause 12. A first network device according to any one of clauses 1 to 11, wherein the processor is further configured to: determine the identity (ID) of the one or more candidate cells provided by the third network device; and then send the ID to the third network device for determining the CSI resource set associated with the one or more candidate cells.

[0195] Clause 13. The first network device of clause 12, wherein the identity of the candidate cell comprises a physical cell identity (PCI), a cell global identity (CGI), or a candidate configuration index, wherein the index is used to identify a candidate configuration for the candidate cell.

[0196] Clause 14. The first network device of any of clauses 1 to 13, wherein the processor is further configured to obtain, from the terminal device, the L1 measurement capability of the terminal device.

[0197] Clause 15. The first network device according to clause 12, wherein the L1 measurement capability of the terminal device comprises one of the following: an indicator for indicating whether the terminal device supports CSI-RS-based L1 measurement of one of the one or more candidate cells; an indicator for indicating whether the terminal device supports synchronization signal block (SSB)-based L1 measurement of one of the one or more candidate cells; an indicator for indicating whether the terminal device supports CSI resource configuration associated with the second network device ... A source configuration is provided independently of a serving cell or a candidate cell; an indicator indicating whether the terminal device supports the CSI resource configuration to be associated with the group of one or more candidate cells; the maximum total number of configured CSI-RS resources and SSBs supported by the terminal device to perform the L1 measurement; the maximum total number of configured CSI-RS resources supported by the terminal device to perform the L1 measurement; the maximum number of periodic, aperiodic or semi-persistent CSI report settings per bandwidth part (BWP) for CSI reporting or beam reporting; or the number of CSI reports of reference signals that the terminal device can measure and process simultaneously.

[0198] Clause 16. The first network device of any of clauses 1 to 15, wherein the processor is further configured to send one or more configurations indicating the set of CSI resources to a third network device providing one of the one or more candidate cells.

[0199] Clause 17. A first network device according to any one of clauses 1 to 16, wherein the first network device is further configured to: send an indicator to the terminal device via the second network device, the indicator instructing the terminal device to maintain a CSI resource configuration set after cell switching, the CSI resource configuration set comprising the CSI resource set and one or more corresponding identities of the one or more candidate cells.

[0200] Clause 18. A second network device comprising a processor and a transceiver, the transceiver being coupled to the processor, wherein the processor is configured to: obtain a set of channel state information (CSI) resources associated with one or more candidate cells for at least one layer 1 (L1) measurement, wherein the set of CSI resources is to be used by a terminal device to perform the at least one L1 measurement; send information indicating the set of CSI resources to the terminal device; and obtain at least one L1 measurement report.

[0201] Clause 19. The second network device of Clause 18, wherein the at least one L1 measurement report is obtained from the terminal device.

[0202] Clause 20. The second network device of Clause 18, wherein the at least one L1 measurement report is obtained from the first network device.

[0203] Clause 21. A second network device according to any one of clauses 18 to 20, wherein the CSI resource set is obtained from a first network device for obtaining the CSI resource set from the one or more candidate cells; and the second network device is further configured to: determine a CSI resource configuration set based on the obtained CSI resource set; wherein sending information indicating the CSI resource set to the terminal device includes: sending the CSI resource configuration set indicating the CSI resource set to the terminal device.

[0204] Clause 22. A second network device according to any one of clauses 18 to 20, wherein obtaining the CSI resource set comprises: receiving a CSI resource configuration set indicating the CSI resource set from a first network device for obtaining the CSI resource set associated with the one or more candidate cells; and wherein sending information indicating the CSI resource set to the terminal device comprises: sending the CSI resource configuration set indicating the CSI resource set to the terminal device.

[0205] Clause 23. The second network device of any of clauses 18 to 22, wherein the second network device is further configured to select a target cell from the one or more candidate cells based on the at least one L1 measurement report.

[0206] Clause 24. A terminal device comprising a processor and a transceiver, the transceiver being coupled to the processor, wherein the processor is configured to: receive information indicating a set of channel state information (CSI) resources associated with one or more candidate cells for at least one layer 1 (L1) measurement from a second network device serving the terminal device; perform at least one L1 measurement for the set of CSI resources; and send at least one L1 measurement report.

[0207] Clause 25. A terminal device according to clause 24, wherein receiving information indicating the CSI resource set from the second network device includes: receiving a CSI resource configuration set indicating the CSI resource set from the second network device; and wherein sending the at least one L1 measurement report includes: sending at least one L1 measurement result for the one or more candidate cells to the second network device.

[0208] Clause 26. A terminal device according to clause 24, wherein the terminal device is further configured to receive an indicator from the second network device, the indicator instructing the terminal device to maintain the CSI resource configuration set after cell switching, the CSI resource configuration set comprising the CSI resource set and one or more corresponding identities of the one or more candidate cells.

[0209] Clause 27. A terminal device according to clause 24, wherein receiving information indicating the CSI resource set from the second network device includes: receiving a CSI report configuration set for the one or more candidate cells and a CSI resource configuration set indicating the CSI resource set for the one or more candidate cells from the second network device, and wherein sending the at least one L1 measurement report includes: sending at least one L1 measurement result for the one or more candidate cells and at least one identity of the corresponding one or more candidate cells to the second network device.

[0210] Clause 28. The terminal device of clause 24, wherein the at least one L1 measurement report is sent to a third network device providing the one or more candidate cells.

[0211] In general, the various embodiments of the present disclosure may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software, which may be executed by a controller, microprocessor, or other computing device. Although various aspects of the various embodiments of the present disclosure are illustrated and described as block diagrams, flow charts, or illustrated and described using some other graphical representations, it should be appreciated that the blocks, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general-purpose hardware, or a controller or other computing device, or some combination thereof, as non-limiting examples.

[0212] 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 computer executable instructions included in program modules that are executed in a device on a target real or virtual processor to perform a process or method as described above. Generally speaking, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The functions of program modules can be combined or split between program modules as desired in various embodiments. The machine executable instructions for program modules can be executed in a local device or a distributed device. In a distributed device, the program modules can be located in both a local storage medium and a remote storage medium.

[0213] The program code for performing the disclosed method can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer or other programmable data processing device so that the program code, when executed by the processor or controller, enables the function / operation specified in the flow chart and / or block diagram to be realized. The program code can be executed completely on the machine, partially on the machine, as an independent software package, partially on the machine and partially on a remote machine, or completely on a remote machine or server.

[0214] The above program code can be embodied on a machine-readable medium, which can be any tangible medium that can contain or store a program for use by or in conjunction with an instruction execution system, device or apparatus. The machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. The machine-readable medium can include, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared or semiconductor system, device or apparatus, or any suitable combination of the foregoing. More specific examples of machine-readable storage media may include an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0215] Further, although operations are described in a particular order, this should not be understood as requiring that the operations be performed in the particular order shown or in a sequential order, or that all illustrated operations be performed to achieve a desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details have been included in the above discussion, these details should not be interpreted as limiting the scope of this disclosure, but rather as describing features that may be specific to a particular embodiment. Certain features described in the context of separate embodiments may also be implemented in combination in a single embodiment. On the contrary, the various features described in the context of a single embodiment may also be implemented separately in multiple embodiments or implemented in any suitable subcombination.

[0216] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it should be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Instead, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A first network device, comprising: processor, and a transceiver, coupled to the processor, wherein the processor is configured to: obtaining a set of channel state information (CSI) resources associated with one or more candidate cells for at least one layer 1 (L1) measurement, wherein the set of CSI resources is to be used by a terminal device to perform the at least one L1 measurement; and Sending, via the transceiver, information indicating the CSI resource set to a second network device serving the terminal device.

2. The first network device according to claim 1, wherein the processor is further configured to: determining a CSI resource configuration set based on the obtained CSI resource set, the CSI resource configuration set comprising the CSI resource set and one or more corresponding identities of the one or more candidate cells, and The sending of the information to the second network device includes: The CSI resource configuration set indicating the CSI resource set is sent to the second network device.

3. The first network device according to claim 1, wherein the processor is further configured to: A CSI resource configuration set is received from the second network device, the CSI resource configuration set comprising the CSI resource set and one or more corresponding identities of the one or more candidate cells, wherein the CSI resource configuration set is determined by the second network device based on the received CSI resource set.

4. The first network device according to claim 2 or 3, wherein the processor is further configured to: The CSI resource configuration set indicating the CSI resource set is sent to the terminal device via the second network device.

5. The first network device according to any one of claims 1 to 4, wherein the processor is further configured to: determining a number of the CSI resources in the set of CSI resources to be provided for a candidate cell, wherein the candidate cell is a candidate cell among the one or more candidate cells provided by a third network device; and Sending, to the third network device, the number used to determine the CSI resource sets associated with the one or more candidate cells.

6. The first network device according to any one of claims 1 to 5, wherein the processor is further configured to: determining identities (IDs) of the one or more candidate cells provided by a third network device; and The ID is sent to the third network device for determining the CSI resource set associated with the one or more candidate cells.

7. The first network device of clause 6, wherein the identity of the candidate cell comprises a physical cell identity (PCI), a cell global identity (CGI), or a candidate configuration index, wherein an index is used to identify a candidate cell configuration for the candidate cell.

8. The first network device according to any one of claims 1 to 7, wherein the processor is further configured to: An L1 measurement capability of the terminal device is obtained from the terminal device.

9. The first network device according to claim 8, wherein the L1 measurement capability of the terminal device comprises one of the following: An indicator, used to indicate whether the terminal device supports CSI-RS-based L1 measurement of one of the one or more candidate cells; an indicator, used to indicate whether the terminal device supports L1 measurement based on a synchronization signal block (SSB) for one of the one or more candidate cells; An indicator, used to indicate whether the terminal device supports CSI resource configuration and is also associated with the second network device; An indicator for indicating whether the terminal device supports the CSI resource configuration being provided independently of the serving cell or the candidate cell; an indicator, used to indicate whether the terminal device supports association of the CSI resource configuration with the group of one or more candidate cells; the maximum total number of configured CSI-RS resources and SSBs supported by the terminal device to perform the L1 measurement; the maximum total number of configured CSI-RS resources supported by the terminal device for performing the L1 measurement; Maximum number of periodic or aperiodic or semi-persistent CSI reporting settings per bandwidth part (BWP) for CSI reporting or beam reporting; or The terminal device is capable of simultaneously measuring and processing the number of CSI reports of the reference signal.

10. The first network device according to claim 1 or 9, wherein the first network device is further configured to: An indicator is sent to the terminal device via the second network device, the indicator instructing the terminal device to maintain a CSI resource configuration set after cell switching, the CSI resource configuration set comprising the CSI resource set and one or more corresponding identities of the one or more candidate cells.

11. A second network device, comprising: processor, and a transceiver, coupled to the processor, wherein the processor is configured to: A set of channel state information (CSI) resources associated with one or more candidate cells for at least one layer 1 (L1) measurement is obtained, wherein the set of CSI resources is to be used by a terminal device to perform the at least one L1 measurement. Sending information indicating the CSI resource set to the terminal device; as well as Obtain at least one L1 measurement report.

12. The second network device according to claim 11, wherein the CSI resource set is obtained from a first network device, and the first network device is configured to obtain the CSI resource set from the one or more candidate cells; and The second network device is further configured to: Determining a CSI resource configuration set based on the obtained CSI resource set; wherein sending information indicating the CSI resource set to the terminal device includes: Sending the CSI resource configuration set indicating the CSI resource set to the terminal device.

13. The second network device according to claim 11, wherein obtaining the CSI resource set comprises: receiving, from a first network device for obtaining the CSI resource set associated with the one or more candidate cells, a CSI resource configuration set indicating the CSI resource set; as well as The sending of information indicating the CSI resource set to the terminal device includes: Sending the CSI resource configuration set indicating the CSI resource set to the terminal device.

14. A terminal device comprising: processor, and a transceiver, coupled to the processor, wherein the processor is configured to: receiving, from a second network device serving the terminal device, information indicating a set of channel state information (CSI) resources associated with one or more candidate cells for at least one layer 1 (L1) measurement; performing the at least one L1 measurement on the CSI resource set; as well as Send at least one L1 measurement report.

15. The terminal device according to claim 14, wherein the terminal device is further configured to: An indicator is received from the second network device, instructing the terminal device to maintain a CSI resource configuration set after cell switching, the CSI resource configuration set comprising the CSI resource set and one or more corresponding identities of the one or more candidate cells.

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