L1 / L2 inter-cell mobility execution

Abstract

Embodiments include a method for a user equipment (UE) configured to communicate with a radio access network (RAN) node, the RAN node comprising a central unit (CU) and a distributed unit (DU) providing a serving cell for the UE. Such a method includes receiving, from a DU, a low-layer signaling message indicating that the UE should perform L1 / L2-based inter-cell mobility for a first candidate cell provided by a candidate DU. The low layer signaling message includes an indicator or identification of the first candidate cell, and an indication of a first TCI state to be used by the UE for communicating with the first candidate cell. Such a method includes performing an L1 / L2 mobility procedure with a first candidate cell and communicating in the first candidate cell based on a first TCI state. Other embodiments include complementary methods of candidate DUs for service, as well as UEs and DUs configured to perform such methods.

Description

Technical Field

[0001] The present application relates generally to the field of wireless networks, and more particularly to improving the mobility of a user equipment (UE) between multiple cells in a wireless network, in particular cells provided by different distributed units (DUs) that may be associated with a single centralized unit (CU). introduce

[0002] Currently, fifth generation (5G) cellular systems are being standardized within the 3rd Generation Partnership Project (3GPP). 5G is being developed for maximum flexibility to support multiple and very different use cases. These include enhanced mobile broadband (eMBB), machine type communications (MTC), ultra-reliable low latency communications (URLLC), sidelink device-to-device (D2D), and several other use cases.

[0003] Figure 1 A high-level view of an exemplary 5G network architecture consisting of a Next Generation Radio Access Network (NG-RAN, 199) and a 5G Core (5GC, 198) is shown. The NG-RAN may include one or more gNodeBs (gNBs) connected to the 5GC via one or more NG interfaces, such as gNBs (100, 150) connected via corresponding interfaces (102, 152). More specifically, the gNB may be connected to one or more access and mobility management functions (AMFs) in the 5GC via corresponding NG-C interfaces, and to one or more user plane functions (UPFs) in the 5GC via corresponding NG-U interfaces. The 5GC may include various other network functions (NFs), such as a session management function (SMF).

[0004] Although not shown, in some deployments, the 5GC may be replaced by an evolved packet core (EPC), which is typically already used with long term evolution (LTE) evolved UMTS RAN (E-UTRAN). In such deployments, gNBs (e.g., 100, 150) may be connected to one or more mobility management entities (MMEs) in the EPC 198 via corresponding S1-C interfaces. Similarly, the gNBs may be connected to one or more serving gateways (SGWs) in the EPC via corresponding NG-U interfaces.

[0005] In addition, the gNBs may be connected to each other via one or more Xn interfaces, such as an Xn interface (140) between gNBs (100, 150). The radio technology used for NG-RAN is generally referred to as "New Radio" (NR). With respect to the NR interface to the UE, each gNB may support frequency division duplex (FDD), time division duplex (TDD), or a combination thereof. Each gNB may serve a geographic coverage area comprising one or more cells, and in some cases, may also use various directional beams to provide coverage in the respective cells. In general, a DL "beam" is a coverage area of ​​a network sent reference signal (RS) that can be measured or monitored by a UE.

[0006] NG-RAN is layered into Radio Network Layer (RNL) and Transport Network Layer (TNL). The NG-RAN architecture, i.e., NG-RAN logical nodes and the interfaces between them, is defined as part of the RNL. For each NG-RAN interface (NG, Xn, F1), the relevant TNL protocols and functions are specified. TNL provides services for user plane transport and signaling transport.

[0007] Figure 1 The NG RAN logical nodes shown include a central unit (CU or gNB-CU, such as 110) and one or more distributed units (DU or gNB-DU, such as 120, 130). The CU is a logical node that hosts high-layer protocols and performs various gNB functions (such as controlling the operation of the DU). The DU is a decentralized logical node that hosts low-layer protocols and may include various subsets of gNB functions based on functional partitioning options. Therefore, each of the CU and DU may include various circuits required to perform its respective functions, including processing circuits, communication interface circuits (e.g., transceivers), and power supply circuits.

[0008] gNB-CU through the corresponding F1 logical interface (for example, Figure 1 122 and 132) shown in Figure 1 are connected to one or more gNB-DUs. However, a gNB-DU can be connected to only a single gNB-CU. The gNB-CU and its connected gNB-DUs are visible only to other gNBs and the 5GC as gNBs. In other words, the F1 interface is not visible outside the gNB-CU.

[0009] Figure 2An exemplary configuration of the NR user plane (UP) and control plane (CP) protocol stacks between the UE (210), gNB (220) and AMF (230) is shown. The physical (PHY) layer, medium access control (MAC) layer, radio link control (RLC) layer and packet data convergence protocol (PDCP) layer between the UE and gNB are common to the UP and CP. The PDCP layer provides encryption / decryption, integrity protection, sequence numbering, reordering and duplicate detection for the CP and UP. In addition, PDCP provides header compression and retransmission for UP data.

[0010] On the UP side, Internet Protocol (IP) packets arrive at the PDCP layer as Service Data Units (SDUs), and PDCP creates Protocol Data Units (PDUs) to deliver to the RLC. The Service Data Adaptation Protocol (SDAP) layer handles Quality of Service (QoS), including mapping between QoS flows and Data Radio Bearers (DRBs) and marking QoS Flow Identifiers (QFIs) in UL and DL packets. The RLC delivers the PDCP PDUs to the MAC over a logical channel (LCH). The RLC provides error detection / correction, concatenation, segmentation / reassembly, sequence numbering, reordering of data transmitted to / from upper layers. The MAC provides mapping between LCH and PHY transport channels, LCH prioritization, multiplexing to or demultiplexing from transport blocks (TBs), hybrid ARQ (HARQ) error correction, and dynamic scheduling (on the gNB side). The PHY provides transport channel services to the MAC and handles transmissions on the NR radio interface, for example, via modulation, coding, antenna mapping, and beamforming.

[0011] On the CP side, the non-access stratum (NAS) layer is between the UE and the AMF, and handles UE / gNB authentication, mobility management, and security control. The RRC is located below the NAS in the UE, but terminates at the gNB instead of the AMF. The RRC controls the communication between the UE and the gNB at the radio interface, as well as the mobility of the UE between cells in the NG-RAN. The RRC also broadcasts system information (SI) and performs the establishment, configuration, maintenance, and release of DRBs and signaling radio bearers (SRBs), which are used by the UE. In addition, the RRC controls the addition, modification, and release of carrier aggregation (CA) and dual connectivity (DC) configurations for the UE, and performs various security functions such as key management.

[0012] After the UE is powered on, it will be in the RRC_IDLE state until an RRC connection is established with the network, at which point the UE will transition to the RRC_CONNECTED state (e.g., where data delivery may occur). The UE must perform a Random Access (RA) procedure to move from RRC_IDLE to the RRC_CONNECTED state, where the cell serving the UE is known and an RRC context is established for the UE in the serving gNB so that the UE and gNB can communicate. As part of (or in conjunction with) the RA procedure, the UE also sends an RRCSetupRequest message to the serving gNB.

[0013] Long Term Evolution (LTE) Rel-10 introduced support for channel bandwidths greater than 20 MHz, which was carried over to NR. To maintain compatibility with legacy UEs from earlier releases (e.g., Rel-8), wideband LTE Rel-10 carriers appear as multiple component carriers (CCs), each with the structure of a Rel-8 carrier. Rel-10 UEs can receive multiple CCs based on carrier aggregation (CA). CCs can also be thought of as "cells", such that a UE in CA has one primary cell (PCell) and one or more secondary cells (SCells). These are collectively referred to as "cell groups". Starting from Rel-15, NR also supports CA.

[0014] As specified in 3GPP document RP-213565, NR Rel-18 includes work items on NR mobility enhancements, which are included in the technical area of ​​L1 / L2-based inter-cell mobility. When a UE moves between the coverage areas of two cells, a serving cell change needs to be made at some point. Currently, serving cell changes are triggered by layer 3 (L3, e.g., RRC) measurements and involve RRC signaling to change PCell and PSCell (e.g., when dual connectivity is configured) and release / add SCell (e.g., when CA is configured).

[0015] Currently, all inter-cell mobility involves a complete Layer 2 (L2) and Layer 1 (L1, i.e., PHY) reset, resulting in longer latency, greater signaling overhead, and longer outages than for intra-cell beam switching. Therefore, the goal of Rel-18 L1 / L2 mobility enhancements is to facilitate serving cell changes through L1 / L2 signaling to address these issues and / or difficulties. Summary of the invention

[0016] These Rel-18 L1 / L2 mobility enhancements must also take into account Figure 1The split CU / DU architecture shown in and discussed above, including for intra-DU and inter-DU / intra-CU cell changes, where the source cell and target cell of the UE are served by different source DUs and target DUs associated with a single CU. However, there are various problems, issues and / or difficulties.

[0017] For example, since one of the goals of L1 / L2 inter-cell mobility is to reduce the interruption time of UE data transmission, the UE needs to be ready to communicate with the target cell when (or shortly thereafter) the L1 / L2 signaling for mobility execution is received from the source cell. As a more specific example, the UE must be able to send UL data or scheduling requests (SRs) to the target cell and / or monitor DL ​​control channels (e.g., PDCCH) from the target cell. However, currently, the UE does not have the necessary information about the target cell configuration (e.g., TCI state) to initiate communication in a way that meaningfully reduces the interruption time.

[0018] It is an object of embodiments of the present disclosure to address these and related problems, issues and / or difficulties, thereby facilitating UE L1 / L2 mobility between cells in a RAN (e.g., NG-RAN).

[0019] Some embodiments of the present disclosure include methods (eg, procedures) for a UE configured to communicate with a RAN node including a CU and a DU providing a serving cell for the UE.

[0020] The exemplary methods include receiving a low layer signaling message from the DU indicating that the UE should perform L1 / L2 based inter-cell mobility for a first candidate cell provided by the candidate DU. The low layer signaling message includes an indicator or identification of the first candidate cell and an indication of a first TCI state to be used by the UE to communicate with the first candidate cell. The exemplary methods also include: performing an L1 / L2 mobility procedure to the first candidate cell, and communicating in the first candidate cell based on the first TCI state.

[0021] In some embodiments, the indication of the first TCI state is a TCI state identifier. In other embodiments, the indication of the first TCI state is an index of a first beam or reference signal (RS) sent in the first candidate cell.

[0022] In some of these embodiments, the exemplary methods further include receiving an RRCReconfiguration message from the CU via the DU, the RRCReconfiguration message including a configuration associated with one or more candidate cells for L1 / L2-based inter-cell mobility, the one or more candidate cells including a first candidate cell. Each candidate cell configuration includes a plurality of TCI state configurations, and each TCI state configuration includes an index of a beam or RS arranged as a quasi-co-location (QCL) source. In such embodiments, the exemplary methods further include selecting a TCI state configuration in the TCI state configuration that includes an index of a first beam or RS as a QCL source as the first TCI state.

[0023] Other embodiments include methods (eg, processes) for a DU of a RAN node that is coupled to a CU of the RAN node and configured to provide a serving cell for a UE.

[0024] The exemplary methods include selecting a first candidate cell provided by the candidate DU for L1 / L2-based inter-cell mobility of a UE served by the DU via a serving cell. The exemplary methods also include sending a low layer signaling message to the UE indicating that the UE should perform L1 / L2-based inter-cell mobility on the first candidate cell. The low layer signaling message includes an indicator or identification of the first candidate cell and an indication of a first TCI state to be used by the UE to communicate with the first candidate cell.

[0025] In some embodiments, these exemplary methods may further include receiving, from the UE, results of measurements performed by the UE on multiple beams or RSs transmitted in the first candidate cell. The measurement results include corresponding indexes of the multiple beams or RSs. In some of these embodiments, the multiple beams or RSs include one or more of the following: SSBs and CSI-RSs. In some of these embodiments, the first TCI state is associated with a first beam or RS having a measurement result (e.g., the highest SS-RSRP) that is most favorable for L1 / L2 mobility for the first candidate cell.

[0026] In some embodiments, the indication of the first TCI state is an index of the first beam or RS. In other of these embodiments, the indication of the first TCI state is a TCI state identifier. In some embodiments, the candidate DU is associated with a CU and / or is part of a RAN node.

[0027] Other embodiments include methods (eg, processes) for a candidate DU configured to communicate with a CU of a RAN node.

[0028] These exemplary methods include receiving a request to configure at least one candidate cell for L1 / L2-based inter-cell mobility to the UE from a CU or from a DU serving the UE via a serving cell. These exemplary methods also include sending a configuration for one or more candidate cells provided by the candidate DU to the CU or DU, the one or more candidate cells including a first candidate cell. These exemplary methods also include receiving a message from the DU indicating an L1 / L2 mobility process performed by the UE. The message includes an indicator or identifier of a first candidate cell for L1 / L2-based inter-cell mobility of the UE, and an indication of a first TCI state to be used by the UE to communicate with the first candidate cell. These exemplary methods also include communicating with the UE in the first candidate cell based on the first TCI state.

[0029] In some embodiments, the candidate DU is associated with the CU and / or is part of the RAN node. In some embodiments, the indicator or identification of the first candidate cell and the indication of the first TCI state are received in a copy or encapsulation of a low layer signaling message sent by the DU to the UE.

[0030] In some embodiments, the indication of the first TCI state is an index of the first beam or RS sent in the candidate cell. In such embodiments, these exemplary methods may also include determining the first TCI state or its identifier based on the index of the first beam or RS and a mapping between the TCI state identifier used in the first candidate cell and the index of the beam or RS sent in the first candidate cell. In other embodiments, the indication of the first TCI state is a TCI state identifier.

[0031] Other embodiments include UEs and DUs configured to perform operations corresponding to any of the exemplary methods described herein. Other embodiments also include a non-transitory computer-readable medium storing computer-executable instructions that, when executed by a processing circuit, configure such UEs and DUs to perform operations corresponding to any of the exemplary methods described herein.

[0032] These and other embodiments described herein can facilitate the execution of L1 / L2 inter-cell mobility much faster than existing L3-based inter-cell mobility because the execution phase is separated from the preparation phase, so that the timing of the low-layer signaling that triggers the execution of L1 / L2 inter-cell mobility depends on the judgment of the serving DU. The advantages are achieved by providing the UE with the TCI state ID or SSB index for the candidate cell in the low-layer signaling that triggers the execution of L1 / L2 inter-cell mobility, thereby facilitating timely communication between the UE and the candidate cell. In addition, by providing the UE with an indication of whether to perform a MAC reset in conjunction with L1 / L2 inter-cell mobility, the embodiments avoid data loss and excessive interruption when a MAC reset is unnecessary. At a high level, the embodiments improve UE mobility in the RAN.

[0033] These and other objects, features and advantages of the present disclosure will become apparent upon reading the following detailed description taken in conjunction with the accompanying drawings briefly described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A high-level view of an exemplary 5G network architecture is shown.

[0035] Figure 2 An exemplary configuration of the NR UP and CP protocol stacks is shown.

[0036] Figure 3 to Figure 4 Shown is the layout Figure 1 Logical architecture of gNB in ​​split CU / DU architecture shown.

[0037] Figure 5 The signaling flow for the inter-DU / intra-CU mobility procedure of a UE is shown.

[0038] Figure 6 includes 6A to 6F , which shows various ASN.1 data structures for configuring L1 / L2 inter-cell mobility candidates to a UE according to various embodiments of the present disclosure.

[0039] Figures 7 to 10 A signaling diagram of a process for configuring a UE for inter-DU L1 / L2 inter-cell mobility from a serving DU to a candidate DU according to various embodiments of the present disclosure is shown, wherein both the serving DU and the candidate DU are associated with the same CU.

[0040] Fig.11 Exemplary methods (eg, processes) for a UE according to various embodiments of the present disclosure are shown.

[0041] Fig.12 Exemplary methods (eg, processes) for serving DUs according to various embodiments of the present disclosure are illustrated.

[0042] Fig.13 Exemplary methods (eg, processes) for candidate DUs according to various embodiments of the present disclosure are shown.

[0043] Fig.14 A communication system according to various embodiments of the present disclosure is shown.

[0044] Fig.15 A UE according to various embodiments of the present disclosure is shown.

[0045] Fig.16 A network node according to various embodiments of the present disclosure is shown.

[0046] Fig.17A host computing system according to various embodiments of the present disclosure is shown.

[0047] Fig.18 is a block diagram of a virtualization environment in which functionality implemented by some embodiments of the present disclosure may be virtualized.

[0048] Fig.19 Communications between a host computing system, a network node, and a UE via multiple connections, at least one of which is a wireless connection, are shown according to various embodiments of the present disclosure. DETAILED DESCRIPTION

[0049] The embodiments briefly summarized above will now be described more fully with reference to the accompanying drawings. These descriptions are provided by way of example to explain the subject matter to those skilled in the art, and should not be construed as limiting the scope of the subject matter to only the embodiments described herein. More specifically, examples illustrating the operation of various embodiments according to the advantages discussed above are provided below.

[0050] Generally, unless clearly defined and / or implied different meanings from the context of use, all terms used herein will be interpreted to a person of ordinary skill in the relevant technical field according to their ordinary meanings. All references to elements, devices, assemblies, devices, steps, etc. will be openly interpreted as referring to at least one instance of elements, devices, assemblies, devices, steps, etc., unless otherwise clearly stated or clearly implied from the context of use. The operation of any method and / or process disclosed herein does not have to be performed in the exact order disclosed, unless the operation is explicitly described as after or before another operation and / or wherein the implicit operation must be after or before another operation. Any feature of any embodiment disclosed herein can be appropriately applied to any other disclosed embodiment. Similarly, any advantage of any embodiment described herein can be appropriately applied to any other disclosed embodiment.

[0051] Furthermore, the following terms are used throughout the description given below:

[0052] Radio access node: As used herein, a "radio access node" (or equivalently a "radio network node", "radio access network node" or "RAN node") may be any node in a radio access network (RAN) that operates to wirelessly send and / or receive signals. Some examples of radio access nodes include, but are not limited to, base stations (e.g., gNBs in 3GPP 5G / NR networks or enhanced or eNBs in 3GPP LTE networks), base station distributed components (e.g., CUs and DUs), high power or macro base stations, low power base stations (e.g., micro, pico, femto or home base stations, etc.), integrated access backhaul (IAB) nodes, transmission points (TPs), transmission reception points (TRPs), remote radio units (RRUs or RRHs), and relay nodes.

[0053] Core network node: As used herein, a "core network node" is any type of node in the core network. Some examples of core network nodes include, for example, mobility management entity (MME), serving gateway (SGW), PDN gateway (P-GW), policy and charging rules function (PCRF), access and mobility management function (AMF), session management function (SMF), user plane function (UPF), charging function (CHF), policy control function (PCF), authentication server function (AUSF), location management function (LMF), etc.

[0054] Wireless device: As used herein, a "wireless device" (or "WD" for short) is any type of device capable, configured, arranged and / or operable to communicate wirelessly with a network node and / or other wireless devices. Wireless communication may involve sending and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves and / or other types of signals suitable for transmitting information through the air. Unless otherwise specified, the term "wireless device" is used interchangeably herein with the term "user equipment" (or "UE" for short), where both terms have different meanings than the term "network node".

[0055] Radio node: As used herein, a "radio node" may be a "radio access node" (or equivalent terms) or a "wireless device".

[0056] Network Node: As used herein, a "network node" is any node that is part of a radio access network (e.g., a radio access node or equivalent term) or a core network (e.g., the core network node discussed above) of a cellular communication network. Functionally, a network node is a device that is capable, configured, arranged and / or operable to communicate directly or indirectly with a wireless device and / or with other network nodes or devices in a cellular communication network, to enable and / or provide wireless access to a wireless device and / or to perform other functions (e.g., management) in a cellular communication network.

[0057] Node: As used herein, the term "node" (without a prefix) may be any type of node that may be in or with a wireless network (including a RAN and / or a core network), including a radio access node (or equivalent terms), a core network node, or a wireless device. However, the term "node" may be limited to a specific type (e.g., a radio access node, an IAB node) based on its specific characteristics in any given context.

[0058] The above definitions are not meant to be exclusive. In other words, the same or similar terms may be used elsewhere in this disclosure to explain and / or describe various terms in the above terms. However, to the extent that such other explanations and / or descriptions conflict with the above definitions, the above definitions shall control.

[0059] Note that the description herein focuses on 3GPP cellular communication systems, and therefore, 3GPP terminology or terminology similar to 3GPP terminology is generally used. However, the concepts disclosed herein are not limited to 3GPP systems. Other wireless systems (including but not limited to Wideband Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB), and Global System for Mobile Communications (GSM)) may also benefit from the concepts, principles, and / or embodiments described herein. In addition, although the term "cell" is used herein, it should be understood that (particularly with respect to 5G NR) a beam may be used instead of a cell, and therefore, the concepts described herein are equally applicable to cells and beams.

[0060] Figure 3 A gNB (such as, Figure 1 The logical architecture of the gNB (100) in FIG. 1 is shown in FIG. 1 . The logical architecture divides the CU into CP and UP functions, referred to as CU-C and CU-U, respectively. In addition, each of the NG, Xn, and F1 interfaces is divided into a CP interface (e.g., NG-C) and a UP interface (e.g., NG-U). Note that Figure 3 The terms "central entity" and "distributed entity" in this document refer to physical network nodes.

[0061] Figure 4 Another exemplary gNB logical architecture is shown, which includes two gNB-DUs, a gNB-CU-CP, and multiple gNB-CU-UPs. The gNB-CU-CP can be connected to the gNB-DU via the F1-C interface, and the gNB-CU-UP can be connected to the gNB-DU via the F1-U interface and to the gNB-CU-CP via the E1 interface. Each gNB-DU can be connected to only one gNB-CU-CP, and each gNB-CU-UP can be connected to only one gNB-CU-CP. A gNB-DU can be connected to multiple gNB-CU-UPs under the control of the same gNB-CU-CP. Similarly, a gNB-CU-UP can be connected to multiple DUs under the control of the same gNB-CU-CP. When referring to operations performed by a "CU" in this document, it should be understood that unless otherwise specified, the operation can be performed by any entity within the CU (e.g., CU-CP, gNB-CU-CP).

[0062] When a UE moves between the coverage areas of two cells, a serving cell change needs to be performed at some point. Currently, serving cell changes are triggered by layer 3 (L3, e.g., RRC) measurements and involve signaling to change PCell and PSCell (e.g., when dual connectivity is configured) and release / add SCell (e.g., when CA is configured). Currently, all inter-cell mobility involves a complete layer 2 (L2) and layer 1 (L1, i.e., PHY) reset. This includes inter-DU / intra-CU cell changes, where the UE's source cell and target cell are served by different source DUs and target DUs associated with a single CU.

[0063] Figure 5 The signaling flow for the inter-DU / intra-CU mobility procedure for a UE (510) is shown, where the source DU (520) and the target DU (530) are associated with the same CU (540), i.e., part of a single RAN node (550), such as a gNB. Figure 5 The operations shown in are given numerical labels, but this is done to facilitate explanation and does not require or imply any order of operations unless explicitly stated otherwise.

[0064] In operation 1, the UE sends a MeasurementReport message to the source DU. In operation 2, the source DU sends a ULRRC message transfer message to the CU to convey the received MeasurementReport message. In operation 2a (which is optional), the CU may send a UE Context Modification Request message to the source DU to query the latest configuration. In operation 2b, the source DU responds with a UE Context Modification Response message including complete configuration information.

[0065] In operation 3, the CU sends a UE context establishment request message to the target DU to create a UE context and establish one or more data bearers. The UE context establishment request message includes HandoverPreparationInformation. In operation 4, the target DU responds to the CU with a UE context establishment response message.

[0066] In operation 5, the CU sends a UE context modification request message to the source DU, which includes the generated RRCReconfiguration message and instructs to stop data transmission for the UE. The source DU also sends a downlink data delivery status frame to notify the CU that the downlink data to the UE has not been successfully sent. In operation 6, the source DU forwards the received RRCReconfiguration message to the UE. In operation 7, the source DU responds to the CU with a UE context modification response message.

[0067] In operation 8, the UE performs a random access procedure at the target DU. The target DU sends a downlink data delivery status frame to notify the CU. Downlink packets that may include PDCP PDUs that were not successfully sent in the source DU are sent from the CU to the target DU. Whether to start sending DL user data to the DU before or after receiving the downlink data delivery status depends on the CU implementation.

[0068] In operation 9, the UE responds to the target DU with an RRCReconfigurationComplete message. In operation 10, the target DU sends an UL RRC Messaging message to the CU to convey the received RRCReconfigurationComplete message. Downlink packets are sent to the UE. In addition, uplink packets are sent from the UE, which are forwarded to the CU via the target DU. In operation 11, the CU sends a UE Context Release Command message to the source DU. In operation 12, the source DU releases the UE context.

[0069] As briefly mentioned above, NR Rel-18 includes work items on NR mobility enhancements, including the technical area of ​​L1 / L2-based inter-cell mobility. The goal of Rel-18 L1 / L2 mobility enhancements is to facilitate serving cell changes via L1 / L2 signaling instead of L3 (e.g., RRC) signaling. One area of ​​interest is inter-DU / intra-CU cell changes, as mentioned above. Figure 5 From the UE's perspective, Figure 5 The process shown may involve longer latency, more signaling overhead, and longer interruptions compared to intra-cell beam switching.

[0070] Therefore, the high-level goal of Rel-18 L1 / L2 mobility enhancement is to facilitate serving cell change via L1 / L2 signaling to address these issues and / or difficulties. Some more specific goals include: ·Configuring and maintaining multiple candidate cells to allow for rapid application of configurations for candidate cells; Dynamic switching mechanism between candidate serving cells (including SpCell and SCell) for potential applicable scenarios based on L1 / L2 signaling; L1 enhancements for inter-cell beam management, including L1 measurements and reporting, and beam indication; Timed advance management; and Support CU-DU interface signaling for L1 / L2 mobility if required.

[0071] These Rel-18 L1 / L2 mobility enhancements must also take into account Figure 1 and Figures 3 to 4The split CU / DU architecture shown in , includes for intra-DU and inter-DU / intra-CU cell changes. In the inter-DU / intra-CU scenario, the candidate cells for L1 / L2 inter-cell mobility are cells served by a neighbor DU of the (serving or source) DU of the PCell (or PSCell for SCG change in DC) currently providing the UE.

[0072] like Figure 5 As shown, the execution of L3 mobility is triggered by the source DU sending an RRCReconfiguration message (operation 6) to the UE, which is generated by the CU and received from the CU during the preparation phase. The message is based on the CU requesting the target DU to establish a UE context and provide the CU with the target cell configuration (e.g., CellGroupConfig). Therefore, when the target DU receives the UE context establishment request (operation 3), it knows that the UE will arrive at the target cell shortly after it receives the RRCReconfiguration from the CU via the source DU, and therefore will soon use any target cell resources reserved for the incoming UE.

[0073] Since one of the goals in L1 / L2 inter-cell mobility is to reduce the interruption time of UE data transmission, the UE needs to be ready to communicate with the target cell when (or shortly thereafter) receiving L1 / L2 signaling for mobility execution from the source cell. For example, the UE must be able to send UL data or scheduling requests (SRs) to the target cell and / or monitor DL ​​control channels (e.g., PDCCH) from the target cell. In other words, the UE needs to know the target cell it is moving to so that it can apply the corresponding configuration, including the correct transmission configuration indicator (TCI) state for the cell. Similarly, when the source DU sends L1 / L2 signaling for mobility execution, the target DU needs to be ready to schedule UL and DL transmissions for the UE in the target cell, as well as to receive scheduling requests (SRs) from the UE.

[0074] Each TCI state includes parameters for configuring a quasi co-location (QCL) relationship between one or more source DL reference signals (RS, e.g., SSB) and one or more other DL RSs (such as DM-RS ports of a physical DL shared channel (PDSCH) or a physical DL control channel (PDCCH) or a channel state information RS (CSI-RS) port of a DL CSI-RS resource). In general, different DL RSs in a base station transmitter may have a QCL relationship when their corresponding antenna ports satisfy the following conditions: the properties of the channel on which a symbol on one antenna port is transmitted can be inferred from the channel on which a symbol on another antenna port is transmitted.

[0075] However, currently, the UE does not have the necessary information about the target cell configuration (e.g., TCI state) to initiate communications in a manner that meaningfully reduces interruption time.

[0076] Embodiments of the present disclosure address these and other problems, difficulties and / or issues by providing a flexible and efficient signaling technique in which a UE receives low-layer signaling from a source DU of a source cell serving the UE to initiate execution of L1 / L2 inter-cell mobility for a target candidate cell configured for the UE. The low-layer signaling includes information about the TCI state of the target candidate cell. The target cell is served by a target DU associated with the same CU as the source DU.

[0077] In some embodiments, the information is a TCI state identifier (ID) from which the UE can directly determine the TCI state configuration of the target candidate cell to be used during L1 / L2 inter-cell mobility execution. In this case, the source DU has a mapping between the TCI state ID and the SSB index of the target cell (e.g., provided by the target DU serving the target cell via the CU), and receives a measurement report including the SSB index of the target cell from the UE. Based on this information, the source DU can select the SSB index for the target cell, determine the corresponding TCI state ID, and provide this information to the UE in low-layer signaling.

[0078] In other embodiments, the information is an SSB index identifying a source RS (i.e., SSB) for a QCL source for a TCI state. Based on the target cell configuration and the SSB index, the UE selects a TCI state for the target cell to be used during L1 / L2 inter-cell mobility execution. Specifically, the UE selects a TCI state configuration in which the indicated SSB index is configured as a QCL source.

[0079] In some embodiments, the low layer signaling may also include an indication of whether the UE should perform a MAC reset when performing the L1 / L2 inter-cell mobility procedure.

[0080] Embodiments may provide various benefits and / or advantages. For example, embodiments may facilitate execution of L1 / L2 inter-cell mobility that is much faster than existing L3-based inter-cell mobility because the execution phase is separated from the preparation phase, so that the timing of the low-layer signaling that triggers the execution of L1 / L2 inter-cell mobility is dependent on the judgment of the source DU. Advantages thereof are achieved by providing the UE with a TCI state ID or SSB index for a candidate cell in the low-layer signaling that triggers the execution of L1 / L2 inter-cell mobility, thereby facilitating timely communication between the UE and the candidate cell. In addition, by providing the UE with an indication of whether a MAC reset should be performed in conjunction with the L1 / L2 inter-cell mobility process, embodiments may avoid data loss and excessive interruption when a MAC reset is unnecessary. At a high level, embodiments improve mobility in a RAN (e.g., NG-RAN).

[0081] In the present disclosure, the following terms may be used interchangeably: "L1 / L2-based inter-cell mobility" (as used in 3GPP work items), "L1 / L2 mobility", "L1 mobility", "L1-based mobility", "L1 / L2-centric inter-cell mobility", "L1 / L2 inter-cell mobility", "inter-cell beam management", and "inter-DU L1 / L2-based inter-cell mobility". These terms refer to scenarios in which a UE receives low-layer (i.e., lower than RRC, such as MAC or PHY) signaling from a network that instructs the UE to change its serving cell (e.g., PCell) from a source cell to a target cell. Exemplary low-layer signaling includes L1 DL Control Information (DCI) and L2 MAC Control Elements (CEs). Compared to conventional RRC signaling, low-layer signaling reduces processing time and interruption time during mobility, and may also increase mobility robustness because the network can respond more quickly to changes in the UE's channel conditions.

[0082] In the present disclosure, the following terms may be used interchangeably with respect to L1 / L2 inter-cell mobility: “neighbor DU”, “non-serving DU”, “candidate DU”, and “target DU”. Similarly, the following terms may be used interchangeably with respect to L1 / L2 inter-cell mobility: “serving DU” and “source DU”.

[0083] Another relevant aspect in L1 / L2 inter-cell mobility is that a cell may be associated with multiple SSBs (or beams), where different SSBs are transmitted in different spatial directions during a half-frame, thereby spanning the coverage area of ​​the cell. A cell may also be associated with multiple CSI-RS resources, which may be transmitted in different spatial directions. Thus, in L1 / L2 inter-cell mobility, receiving low-layer signaling instructing the UE to change from one beam in its serving cell to another beam in a (candidate) neighbor cell also involves changing the serving cell.

[0084] The following description relates to the configuration of L1 / L2-based inter-cell mobility candidate cells (also referred to as "candidate cell configurations") generated by the candidate DU and encapsulated in the RRCReconfiguration message received by the UE when inter-DU L1 / L2 inter-cell mobility is configured. The RRCReconfiguration message may include one or more of these configurations for the corresponding one or more candidate cells served by the candidate DU. Each configuration includes parameters and / or settings that the UE needs to operate in the corresponding candidate cell when receiving low-layer signaling indicating L1 / L2-based inter-cell mobility for the corresponding candidate cell, which becomes the target cell for mobility at this time.

[0085] The configuration of L1 / L2 based inter-cell mobility candidate cells may include parameters of the serving cell (or serving cells), including one or more sets of parameters within the SpCellConfig information element (IE) (or SCellConfig IE in the case of SCell). These parameters may include any of the following: Cell index (e.g., encoded in fewer bits than the cell identifier of the L1 / L2 inter-cell mobility candidate cell). This can be the field 'servCellIndex' or 'candidateCellIndex' of the IE 'ServCellIndex' or IE 'CandidateCellIndex'. After this is configured, the index can be used later in low layer signaling to indicate to the UE that this is the candidate cell to which the UE needs to move in the L1 / L2 inter-cell mobility procedure, and / or to indicate some operation in this specific candidate cell in an RRC message. UE (e.g., UE-specific or UE-dedicated) cell configuration corresponding to the configuration of L1 / L2 based inter-cell mobility candidate cells, where parameters may be adjusted for the UE according to UE capabilities. The UE cell configuration may include parameters defined in the ServingCellConfig IE (defined in 3GPP TS38.331), such as DL and UL frequency configuration (including bandwidth parts), L1 control channels (such as PDCCH, CORESET, PUCCH), L1 data channels (such as PDSCH, PUSCH), etc. Common cell configuration corresponding to the configuration of L1 / L2 based inter-cell mobility candidate cells in ServingCellConfigCommon IE. This can be provided in ReconfigurationWithSync IE or separately. If necessary, the common cell configuration contains, for example, RA configuration for UE to access candidate cells. • Radio link failure configuration(s), such as the value of timer T310, counter N310, counter N311, timer N311. • At least one UE identifier identifying the UE in an L1 / L2 based inter-cell mobility candidate cell, such as a Cell Radio Network Temporary Identifier (C-RNTI).

[0086] In some embodiments, when the UE is configured with multiple L1 / L2 inter-cell mobility candidate cells provided by a neighbor DU, the neighbor DU generates and sends multiple sets of parameters in multiple SpCellConfig IEs to the CU. For example, the UE may receive a list of SpCellConfig IEs, one SpCellConfig IE for each L1 / L2 inter-cell mobility candidate.

[0087] In some embodiments, the configuration of the L1 / L2-based inter-cell mobility candidate cells of the neighbor DU may be a SpCell configuration provided as part of a cell group configuration (e.g., PCell for MCG), and may also include one or more SCell configurations and cell group specific configurations (e.g., cell group identifier, cell group PHY configuration, cell group MAC configuration, simultaneous TCI state configuration for the cell group, etc.). In these embodiments, the UE is configured with a cell group configuration for each neighbor DU candidate cell. An alternative is that the UE receives one configuration for each cell group, where the configuration of the L1 / L2-based inter-cell mobility candidate cells is the SpCell candidate configuration within the group. The low-layer signaling then instructs the UE to change to the configured cell group candidate, for example, from MCG configuration A to MCG configuration B.

[0088] In some embodiments, when the UE is configured with multiple L1 / L2 inter-cell mobility candidates, the neighbor DU generates and sends multiple cell group configurations to the CU, each cell group configuration being associated with a different candidate. For example, the neighbor DU may generate and send a list of CellGroupConfig IEs.

[0089] In some embodiments, the L1 / L2 inter-cell mobility candidate may be in the same frequency as the current PCell, or in a different frequency. In some embodiments, the L1 / L2 inter-cell mobility candidate may be a SCell candidate.

[0090] The RRC signaling implementation for configuration of candidate cells for inter-cell mobility based on L1 / L2 may be implemented in different ways corresponding to various embodiments. Some examples are described below.

[0091] Some embodiments may utilize one RRCReconfiguration message for each candidate cell. In this case, the UE receives multiple RRCReconfiguration messages (lists) within a single RRCReconfiguration message, such as Fig. 6A As shown. Each RRCReconfiguration message identifies and / or includes the configuration of an L1 / L2-based inter-cell mobility candidate cell, which is stored by the UE and applied / used / activated upon receiving low-layer signaling of the corresponding L1 / L2 inter-cell mobility procedure for the candidate cell. As in L3 reconfiguration, this model enables the target node to fully flexibly modify / release / maintain any parameters / fields (e.g., measurement configuration, bearer, etc.) in the existing RRCReconfiguration message.

[0092] As an example of these embodiments, the neighbor DU generates a CellGroupConfig IE for each candidate (including candidate SpCell and (multiple) SCells, if applicable), and the CU generates an RRCReconfiguration message for each candidate based on the corresponding CellGroupConfig IE. These messages are received and stored by the UE for application when the UE later receives an L1 / L2 inter-cell mobility command (e.g., MAC CE) indicating a specific cell in the candidate cells.

[0093] Other embodiments may utilize one CellGroupConfig IE for each candidate cell.With this model, the UE receives a list of CellGroupConfig IEs within the RRCReconfiguration message, where each IE identifies and / or includes the configuration of an L1 / L2 based inter-cell mobility candidate cell. Figure 6B Examples of these embodiments are shown. Each CellGroupConfig IE is stored by the UE and is applied / used / activated upon receipt of low layer signaling of the corresponding L1 / L2 inter-cell mobility procedure for that candidate cell. This model allows a neighbor DU to modify / release / keep any parameter / field that is part of the CellGroupConfig IE, while the rest of the RRCReconfiguration message (where the UE receives the CellGroupConfig IE) remains unchanged. This means that measurement configuration, bearers, security, etc. remain the same and are not changed by the target node.

[0094] As an example of these embodiments, the neighbor DU generates a CellGroupConfig IE for each target candidate (including the candidate SpCell and the associated SCell), and the CU generates an RRCReconfiguration message with a list of CellGroupConfig IEs. These are received and stored by the UE for application when the UE later receives an L1 / L2 inter-cell mobility command (e.g., MAC CE) indicating a specific cell in the candidate cells.

[0095] Other embodiments may provide multiple (K) SpCellConfig IEs and / or multiple (K) ServingCellConfigCommon IEs to the UE in the configuration of L1 / L2 based inter-cell mobility candidate cells. Since the neighbor DU can only modify / release / maintain cell-specific parameters (e.g., bandwidth part, DL / UL configuration) when generating the K SpCellConfig IEs and / or K ServingCellConfigCommon IEs to be provided to the UE, this solution only provides minimal flexibility for the neighbor DU. FIG. 6C to FIG. 6E Examples of these embodiments are shown.

[0096] Other embodiments may provide multiple (K) physical cell identifiers (PCIs) in the same PCell to the UE. Fig. 6F Examples of these embodiments are shown. With this model, multiple PCIs are configured for the same TCI state configuration, where each PCI identifies the configuration of an L1 / L2-based inter-cell mobility candidate cell. This method is not flexible because all parameters / fields for configuring the L1 / L2-based inter-cell mobility candidate cell configuration are fixed, and only PCI, scrambling Id and / or C-RNTI are allowed to be changed for neighbor DUs.

[0097] In various embodiments, the UE has received at least one configuration (or candidate cell configuration) for candidate cells for inter-cell mobility based on L1 / L2 via high-layer (e.g., RRC) signaling. The candidate cell configuration may be (or included in) a cell group configuration (e.g., in a CellGroupConfig IE) or a serving cell configuration (e.g., in a ServingCellConfig and / or ServingCellConfigCommon IE) of candidate cells for L1 / L2 inter-cell mobility. The UE may have received multiple configurations for candidate cells for inter-cell mobility based on L1 / L2 from multiple candidate DUs serving the corresponding candidate cells. In some cases, the serving DU may also be a candidate DU, but the candidate cell provided by the serving DU is a different cell from the UE.

[0098] In some embodiments, the serving (or source) DU determines triggering L1 / L2 inter-cell mobility for the UE to one of the candidate cells previously configured for UE L1 / L2 inter-cell mobility. The determination of the serving DU may be based on one or more reports received from the UE, such as CSI reports, measurement reports, etc. Such reports may include UE measurement information related to one or more configured candidate cells.

[0099] In some embodiments, the measurement information for the L1 / L2 inter-cell mobility candidate cell may include a synchronization signal (SS) reference signal received power (SS-RSRP) measurement for at least one configured / indicated SSB of the L1 / L2 inter-cell mobility candidate cell. The SS-RSRP is measured only between RSs including SSBs having the same SSB index and the same physical cell identifier (PCI) as the L1 / L2 inter-cell candidate cell.

[0100] In some embodiments, the SS-RSRP may be derived as a linear average of the power contributions (in [W]) of resource elements carrying the secondary synchronization signal (SSS) of the L1 / L2 inter-cell candidate cells. In some embodiments, the SS-RSRP determination may also be based on the demodulation reference signal (DMRS) of the physical broadcast channel (PBCH) for the L1 / L2 inter-cell candidate cells and (if indicated by higher layers) the CSI-RS of the L1 / L2 inter-cell candidate cells.

[0101] In one embodiment, the SS-RSRP indicates certain SSBs for performing SS-RSRP measurements, and then the SS-RSRP is measured only from the indicated set of SS / PBCH blocks. In some embodiments, the SS-RSRP is used for the L1-RSRP to be included in the CSI report.

[0102] In some embodiments, the measurement information for the L1 / L2 inter-cell mobility candidate cell may include one of the following: SS reference signal received quality (SS-RSRQ) measurement for at least one configured / indicated SSB of an L1 / L2 inter-cell mobility candidate cell; • SS signal-to-noise and interference ratio (SS-SINR) measurement for at least one configured / indicated SSB of the L1 / L2 inter-cell mobility candidate cell. CSI-RS Received Power (CSI-RSRP) measurement for at least one configured / indicated CSI-RS resource for the L1 / L2 inter-cell mobility candidate cell. In some embodiments, the CSI-RSRP measurement is a linear average over the power contribution (in [W]) of the resource elements of the antenna ports carrying the CSI-RS configured for RSRP measurement within the considered measurement frequency bandwidth in the configured CSI-RS opportunities. • CSI-RS Received Quality (CSI-RSRQ) measurement of at least one configured / indicated CSI-RS resource for L1 / L2 inter-cell mobility candidate cells. • CSI-RS signal-to-noise ratio (CSI-SINR) measurement of at least one configured / indicated CSI-RS resource for L1 / L2 inter-cell mobility candidate cells. - L1 reference signal received power (L1-RSRP) of at least one SSB of the candidate cell based on L1 / L2 inter-cell mobility. • L1 reference signal received power (L1-RSRP) based on at least one CSI-RS resource of the L1 / L2 inter-cell mobility candidate cell. • Layer 1 SINR (L1-SINR) of at least one SSB of the candidate cell based on L1 / L2 inter-cell mobility. • Layer 1 SINR (L1-SINR) based on at least one CSI-RS resource of the L1 / L2 inter-cell mobility candidate cell. • Channel Quality Indicator (CQI) is based on SSB and / or CSI-RS in the CSI resource configuration. Precoding Matrix Indicator (PMI) based on SSB and / or CSI-RS in the CSI resource configuration. • The CSI-RS Resource Indicator (CRI) is based on the SSB and / or CSI-RS in the CSI resource configuration. SS / PBCH Block Resource Indicator (SSBRI) based on SSB and / or CSI-RS in the CSI resource configuration. • Layer Indicator (LI) is based on SSB and / or CSI-RS in CSI resource configuration. • The rank indicator (RI) is based on the SSB and / or CSI-RS in the CSI resource configuration.

[0103] In some embodiments, the serving DU generates and sends to the UE low layer signaling (e.g., MAC CE, DCI, etc.) indicating that the UE should perform L1 / L2 inter-cell mobility to the target cell. The low layer signaling may include one or more of the following indications: Candidate cells for UE to perform L1 / L2 inter-cell mobility; The TCI state of the candidate cell, which the UE considers to be activated in the candidate cell of the UE.

[0104] In some embodiments, the indicated candidate cell may be one of the configured candidate cells for which the UE provides measurement reports to the serving DU, e.g., the UE indicates the candidate cell with the highest RSRP, RSRQ and / or SINR.

[0105] In some embodiments, the indication of the candidate cell may be an identifier comprising N1 (integer) bits, which is mapped to a cell identifier of a target candidate cell having N2>N1 bits. For example, a candidate cell configuration (e.g., previously received via RRC) may include an N1-bit identifier, such that when the UE receives lower layer signaling including an N1-bit identifier, it may match it with the corresponding candidate cell configuration.

[0106] In some embodiments, the indication of the TCI state is a TCI state identifier (ID) from which the UE can directly determine the TCI state configuration of the candidate cell to be used during L1 / L2 inter-cell mobility execution.

[0107] For example, the indicated TCI state may be a TCI state corresponding to the SSB index for which the UE reports the strongest measurement (e.g., SSBRSRP, SSB SINR, SSB RSRQ) for the candidate cell. The SSB index is configured as the QCL source for the indicated TCI state. In other words, the service DU receives SSB measurements for different SSB indexes of the candidate cell from the UE (e.g., SS-RSRP for SSB index = 1, 5, 7), and based on the mapping between the SSB index and the TCI state (or TCI state identifier), the service DU determines which TCI state (or TCI state identifier) ​​of the candidate cell to include in the low-layer signaling. The included TCI state is the TCI state that the UE should use when performing L1 / L2 inter-cell mobility execution.

[0108] Since the TCI state configuration of the candidate cell is generated by the candidate DU serving the cell, the serving DU needs to know the mapping between the SSB index and the TCI state (or identifier) ​​of the candidate cell. In one option, the candidate DU provides the mapping to the serving DU via the CU during the mobility preparation phase. In the preparation phase, the CU requests the candidate DU to configure L1 / L2 inter-cell mobility (for at least one candidate target cell) by sending a UECONTEXT SETUP REQUEST including an indication, which is a request for L1 / L2 inter-cell mobility. The candidate DU generates and sends a target candidate configuration to the CU, including a mapping between the SSB index (or other RS ​​index and / or beam identifier) ​​and the TCI state identifier, for example, in an RRC container or as part of the F1AP message content / payload. The CU provides the mapping to the serving DU so that when the serving DU receives a report with a measurement of the SSB index of the candidate cell, it can map the SSB index to the TCI state (or identifier) ​​of the candidate cell without having to know other details of the TCI state configuration.

[0109] As a more specific example, the candidate DU may provide the following mapping to the serving DU (via the CU): SSB index = 3 → TCI status ID = 4; SSB index = 2 → TCI status ID = 6; SSB index = 7 → TCI status ID = 2; If the serving DU receives a report indicating that SSB Index=7 is the SSB with the strongest RSRP, RSRQ and / or SINR of the candidate cell, it includes TCI State ID=2 in the low layer signaling based on the provided mapping.

[0110] Figure 7 The signaling flows for configuring a UE (710) for inter-DU L1 / L2 inter-cell mobility from a serving DU (720) to a candidate DU (730) according to these embodiments are shown, both of which are associated with the same CU (740). In other words, the serving DU, the candidate DU, and the CU are part of a single RAN node (750). Although Figure 7 The operations shown in the drawings are given numerical labels, but this is done to facilitate explanation and does not require or imply any particular order of operations unless otherwise explicitly stated.

[0111] In operation 1, the CU sends a UE context setup request message to the candidate DU, which includes a request to configure L1 / L2 inter-cell mobility to the UE. In operation 2, the candidate DU responds with a UE context setup response message, which includes the configuration of the candidate cell served by the candidate DU and the mapping between the TCI state ID and the SSB index for the candidate cell. In operation 3, the CU provides the same information to the UE serving the DU in a DL RRC messaging message. If the CU has collected other candidate cell configurations (e.g., from other candidate DUs), it can include them in this message.

[0112] In operations 4 to 5, the serving DU sends an RRCReconfiguration message including the configuration of the L1 / L2 inter-cell mobility candidate cells received from the CU to the UE, and the UE responds with an RRC Reconfiguration Complete message. In operation 6, the serving DU responds to the CU with a UL RRC Messaging message.

[0113] In operation 7, the UE sends one or more CSI reports with measurements of SSBs in the candidate cell to the serving DU, where the strongest measurement is for SSB index = X. The serving DU decides to trigger L1 / L2 inter-cell mobility of the UE to the candidate cell and maps SSB index = X to TCI state ID = Y based on the mapping received in operation 2. In operation 8, the serving DU sends low layer signaling including the candidate cell identity and TCI state ID = Y to the UE. In operation 9, the UE sends an UL message to the candidate DU in the candidate cell based on applying TCI state ID = Y for the candidate cell.

[0114] In other embodiments, the indication of the TCI state is the beam configuration of the candidate cell. For example, the beam configuration may correspond to the beam or RS index for which the UE reports the strongest measurement (e.g., SSB RSRP, SSB SINR, SSB RSRQ) of the candidate cell. More specifically, the beam or RS index is configured as the QCL source of the indicated beam configuration.

[0115] For example, the serving DU receives one or more measurements per RS ​​index of the target candidate cell from the UE (e.g., RSRP of RS index = 1, RSRP of RS index = 5, and RSRP of RS index = 7), and based on the mapping between the RS index and the beam configuration (or configuration identifier), the serving DU determines which beam configuration (or identifier) ​​of the candidate cell to include in the low layer signaling to the UE. The included beam configuration is the beam configuration that the UE should use when performing L1 / L2 inter-cell mobility execution.

[0116] Since the beam configuration of the candidate cell is generated by the candidate DU serving the cell, the serving DU needs to know the mapping between the beam or RS index and the beam configuration (or identifier) ​​of the candidate cell. This can be handled in a similar manner to the mapping between the SSB index and the TCI state (or identifier) ​​discussed above.

[0117] In other embodiments, the indication of the TCI state is a beam or RS index that identifies an RS (e.g., SSB) as a QCL source for the TCI state. Based on the previously received candidate cell configuration and the beam or RS index, the UE selects the TCI state of the candidate cell to use during L1 / L2 inter-cell mobility execution. Specifically, the UE selects a TCI state configuration in which the indicated beam or RS index is configured as a QCL source.

[0118] For example, the indicated beam or RS index can be the SSB index for which the UE reports the strongest measurement (e.g., SSBRSRP, SSB SINR, SSB RSRQ) for the candidate cell. The SSB index is configured as the QCL source for a particular TCI state of the candidate cell. In other words, the serving DU receives SSB measurements for different SSB indexes of the candidate cell from the UE (e.g., SS-RSRP for SSB index = 1, 5, 7), and selects the SSB index corresponding to the strongest measurement.

[0119] For example, the indicated TCI state may be a TCI state corresponding to the SSB index for which the UE reports the strongest measurement (e.g., SSBRSRP, SSB SINR, SSB RSRQ) for the candidate cell. The SSB index is configured as the QCL source for the indicated TCI state. In other words, the serving DU receives measurements of different SSB indexes for the candidate cell from the UE (e.g., SS-RSRP for SSB index = 1, SSB index = 5, SSB index = 7), determines that SSB index = 7 has the strongest measurement, and includes SSB index = 7 in the low layer signaling to the UE.

[0120] Note that in these embodiments, the serving DU does not perform any mapping between SSB index and TCI state. Instead, upon receiving the low layer signaling, the UE selects a TCI state in which SSB index = 7 is configured as the QCL source according to the previously received candidate cell configuration.

[0121] For example, the candidate cell configuration generated by the candidate DU and provided to the UE includes the following TCI state configuration: SSB index = 3 as QCL source (e.g., type D) TCI state ID = 4; SSB index = 2 as QCL source (e.g., type D) TCI state ID = 6; SSB index = 7 as QCL source (e.g., type D) TCI state ID = 2;

[0122] If the serving DU receives a UE report indicating that SSB index = 7 is the SSB with the strongest RSRP, RSRQ and / or SINR of the candidate cell, the serving DU includes SSB index = 7 in the low layer signaling based on the provided mapping. The UE determines based on the candidate cell configuration that it needs to use TCI state ID = 2 in the candidate cell, where SSB index = 7 is the QCL source.

[0123] As mentioned above, the serving DU does not need to know the mapping between the SSB index and TCI state identifier of the candidate cell. Figure 7 Unlike the illustrated embodiment, the candidate DU does not need to provide the mapping between the SSB index and the TCI state identifier of the candidate cell to the CU or serving DU during the preparation phase.

[0124] Figure 8 The signaling flow for configuring a UE (710) for inter-DU L1 / L2 inter-cell mobility from a serving DU (720) to a candidate DU (730) according to these embodiments is shown, where both the serving DU and the candidate DU are associated with the same CU (740). In other words, the serving DU, the candidate DU and the CU are part of a single RAN node (750). Although Figure 8 The operations shown in the drawings are given numerical labels, but this is done to facilitate explanation and does not require or imply any particular order of operations unless otherwise explicitly stated.

[0125] Operations 1 to 7 are similar to those above for Figure 7 The corresponding operations described above are as described above, except that the mapping between the TCI state ID and the SSB index is not included in the messages of operations 2 to 3. In operation 8, the serving DU sends a low layer signaling including an identifier of the candidate cell and SSB index = X to the UE. Based on the candidate cell configuration received in operation 4, the UE selects a TCI state (indicated by TCI state ID = Y) in which SSB index = X is configured as a QCL resource. In operation 9, based on applying TCI state ID = Y for the candidate cell, the UE sends a UL message to the candidate DU in the candidate cell.

[0126] In some embodiments, the serving DU may also include in the low layer signaling an indication of whether the UE should perform a random access (RA) procedure when performing L1 / L2 inter-cell mobility to a candidate cell. RA may not be required when the serving cell and the candidate cell overlap, are adjacent, or are close. As a specific example, the serving DU may determine to switch the UE's PCell to another cell served by the same DU (e.g., the current SCell for the UE). Other conditions that may cause the serving DU to indicate that RA is required in a candidate cell include: The candidate cell’s time alignment is different from the source cell’s time alignment; The candidate cell's time alignment timer has expired; and / or • The time alignment of the candidate cells is unknown.

[0127] In one example, the indication of whether the UE should perform RA can be explicit, such as a one-bit indication, where "1" indicates that RA is required and "0" indicates that RA is not required. In another example, the indication of whether the UE should perform RA can be an index to one of a set of pre-configured contention-free random access (CRFA) resources in the candidate cell configuration for L1 / L2 inter-cell mobility. The pre-configured resources can be RA preambles, RA opportunities, SSBs, or CSI-RS. In another example, the indication can explicitly indicate that contention-based random access (CBRA) should be used in the candidate cell in conjunction with L1 / L2 mobility.

[0128] In another example, the indication of whether the UE should perform RA may be an indication of whether the UE may maintain time alignment of the serving cell when performing L1 / L2 inter-cell mobility to the candidate cell. Note that the indication that the UE may maintain the same time alignment of the serving cell implicitly indicates that the UE does not need to perform RA in the candidate cell, which would involve obtaining time alignment. In some variants, the indication may also indicate whether the UE may maintain the same DL time alignment, the same UL time alignment, both, or neither.

[0129] In some embodiments, the UE may determine whether RA in conjunction with L1 / L2 inter-cell mobility is required in a candidate cell based on one or more of the following criteria (e.g., determined by the UE): · The time alignment of the candidate cell is different from the time alignment of the source cell; The candidate cell's time alignment timer has expired; and • The time alignment of the candidate cells is unknown.

[0130] In some embodiments, when the serving DU generates and sends to the UE low layer signaling (e.g., MAC CE, DCI) indicating that the UE should perform L1 / L2 inter-cell mobility to the candidate cell, the serving DU also sends to the CU and / or the candidate DU one or more of the following: An indication of the candidate cell selected by the serving DU for L1 / L2 inter-cell mobility of the UE, such as a cell identifier (e.g. PCI, CGI) or a configuration identifier; An indication of the TCI state (e.g., TCI state ID, SSB index, etc.) of the candidate cells to be used by the UE for L1 / L2 inter-cell mobility; and • A copy or encapsulation of the low layer signalling for L1 / L2 inter-cell mobility sent or to be sent by the serving DU to the UE, including an indication of the selected candidate cell and the TCI status.

[0131] Based on receiving such information, the candidate DU can determine that the incoming UE will use a specific TCI state in the candidate cell and communicate with the UE accordingly.

[0132] Fig. 9 The signaling of another exemplary process for the CU (740) to configure the UE (710) with L1 / L2 inter-cell mobility from the serving DU (720) to the candidate DU (730) according to some of these embodiments is shown, both the serving DU and the candidate DU are associated with the CU. In other words, the serving DU, the candidate DU and the CU are part of a single RAN node (750). Fig. 9 Shown with Figures 7 and 8 Many of the same operations are performed, so for brevity, the following will omit the Fig. 9 Descriptions of these operations in .

[0133] exist Fig. 9 In the low-layer signaling, the UE receives a target candidate cell indication and a TCI state ID. The serving DU generates the TCI state ID in the low-layer signaling based on a mapping between the SSB index of the candidate cell and the TCI state ID previously received from the candidate DU via the CU. More specifically, the serving DU determines the TCI state ID of the candidate cell based on measurement information of at least one SSB index of the candidate cell reported from the UE.

[0134] When the serving DU sends low layer signaling to the UE, it also sends an indication (including TCI state ID) to the CU, which sends it to the candidate DU. This not only updates the CU with the latest cell that the UE is connected to, but also indicates to the candidate DU that the incoming UE will use the TCI state in the candidate cell.

[0135] The serving DU may send an indication of L1 / L2 inter-cell mobility (including the TCI state ID) to the CU before or after it sends the low layer signaling to the UE (including after it has received an acknowledgement of the low layer signaling from the UE). Alternatively, the serving DU may wait a predetermined amount of time after it sends the low layer signaling before sending the TCI state ID to the CU.

[0136] Fig.10 The signaling of another exemplary process for the CU (740) to configure the UE (710) with L1 / L2 inter-cell mobility from the serving DU (720) to the candidate DU (730) according to other embodiments of these embodiments is shown, and both the serving DU and the candidate DU are associated with the CU. In other words, the serving DU, the candidate DU and the CU are part of a single RAN node (750). Fig.10 Shown with Figures 7 and 8 Many of the same operations are performed, so for brevity, the following will omit the Fig.10 Descriptions of these operations in .

[0137] exist Fig.10 In the embodiment, the UE receives low layer signaling including an indication of a candidate cell and an SSB index (operation 8). The UE determines the TCI state ID of the candidate cell in execution by activating a TCI state with a received SSB index configured as a QCL source (e.g., for QCL type D or other types associated with spatial directional correlation).

[0138] When the serving DU sends low-layer signaling to the UE, it also sends an indication (including the SSB index) to the CU, which forwards it to the candidate DU. This not only updates the CU with the latest cell to which the UE is connected, but also indicates to the candidate DU that the incoming UE will use the SSB index (or corresponding TCI state) in the candidate cell.

[0139] The serving DU may send an indication of L1 / L2 inter-cell mobility (including SSB index) to the CU before or after it sends low-layer signaling to the UE (including after it has received an acknowledgement of the low-layer signaling from the UE). Alternatively, the serving DU may wait a predetermined amount of time after it sends the low-layer signaling before sending the TCI state ID to the CU.

[0140] exist Figures 9 and 10In some variations of the illustrated embodiment, the UE does not send an UL message in the candidate cell upon receiving low-layer signaling (operation 9), but first monitors the PDCCH of the candidate cell according to the indication in the low-layer signaling (e.g., the TCI state ID or SSB index to be mapped to the TCI state by the UE). If the serving DU knows in advance that the UE is to first monitor the PDCCH of the candidate cell before sending the UL message in step 9, the serving DU triggers step 8a. Otherwise, if the serving DU knows that the UE sends directly in the UL (operation 9), it can skip operation 8a. In the case where low-layer signaling triggers the UE to perform random access, the UE selects a beam (e.g., an SSB index / CSI-RS resource identifier) ​​and sends a preamble associated with the selected beam so that the candidate DU knows the beam selected by the UE, and thus there is no need to indicate which TCI state ID and / or beam ID and / or SSB index in operation 8.

[0141] In some embodiments, upon receiving low layer signaling with an indication that a random access procedure is not required when performing L1 / L2 inter-cell mobility to a target candidate cell, the UE starts sending UL messages in the target candidate cell. In this case, the first UL message that the UE can send in the L1 / L2 inter-cell candidate cell is UL data or a scheduling request.

[0142] In some embodiments, an indication of L1 / L2 inter-cell mobility execution including candidate cells and possible TCI state IDs and / or SSB indices is provided from the serving DU to the CU in a UE context modification required message via F1AP (operation 8a). The CU provides this information to the candidate DU in a UE context modification request message via F1AP (operation 8b).

[0143] In some embodiments, the UE receives an indication of whether a MAC reset should be performed when the UE performs L1 / L2 inter-cell mobility to the candidate cell. In one example, the indication is provided in an indication of performing L1 / L2 inter-cell mobility to the candidate cell (e.g., Fig.10 In another example, the indication is provided in the configuration of one or more L1 / L2 inter-cell mobility candidate cells (e.g., Fig.10 In various embodiments, the MAC reset may include one or more of the following actions: Initialize state variables; Stop, start or restart the timer; · Setting the New Data Indicator (NDI) for the UL HARQ process to zero; Stop the ongoing MAC process; Cancel the triggered MAC process; Refresh the message buffer; Reset the counter; and Release the C-RNTI.

[0144] In some embodiments, the UE selectively performs a MAC reset when performing L1 / L2 inter-cell mobility to a candidate cell, such as by not performing any, some, or all of the actions listed above. For example, the selective action is based on an indication received from the serving DU, such as the type (e.g., DCI or MAC CE) or content of low-layer signaling indicating that L1 / L2 inter-cell mobility is to be performed. Alternatively, the indication may be part of a candidate cell configuration received via high-layer signaling.

[0145] In some embodiments, the serving DU receives an indication from the CU and / or from the candidate DU as to whether the UE needs to perform a MAC reset when performing L1 / L2 inter-cell mobility to one of the UE's configured L1 / L2 inter-cell mobility candidate cells.

[0146] In some embodiments, the serving DU sends an indication to the CU and / or candidate DUs as to whether the UE needs to perform a MAC reset when performing L1 / L2 inter-cell mobility to one of the UE's configured L1 / L2 inter-cell mobility candidate cells.

[0147] In some embodiments, the serving DU determines whether the UE needs to perform a MAC reset when performing L1 / L2 inter-cell mobility for a candidate cell, and sets the indication accordingly. In one example, the determination is based on an indication received from the CU and / or from the candidate DU. In another example, the determination is based on whether both the source and the candidate target cell are controlled by the same DU. For example, when both the source and the candidate target cell are controlled by the same DU, the indication indicates that the UE does not perform a MAC reset when performing L1 / L2 inter-cell mobility for the candidate cell. In another example, the determination is based on whether both the source and the candidate target cell are controlled by the same hardware or software unit.

[0148] In some embodiments, the CU sends an indication to the UE as to whether the UE needs to perform a MAC reset when performing L1 / L2 inter-cell mobility for a candidate cell. In one example, the indication is provided within the configuration of one or more L1 / L2 inter-cell mobility candidate cells to be applied.

[0149] In some embodiments, the CU receives an indication from the serving DU or the candidate DU as to whether the UE needs to perform a MAC reset when performing L1 / L2 inter-cell mobility to one of the configured L1 / L2 inter-cell mobility candidate cells of the UE.

[0150] In some embodiments, the CU sends an indication to the serving DU or the candidate DU as to whether the UE needs to perform a MAC reset when performing L1 / L2 inter-cell mobility to one of the UE's configured L1 / L2 inter-cell mobility candidate cells.

[0151] In some embodiments, the CU determines whether the UE needs to perform a MAC reset when performing L1 / L2 inter-cell mobility to a candidate cell, and sets the indication accordingly. In various embodiments, the determination is based on one or more of the following: Explicit indication from serving DU or candidate DU • Whether the source cell and the candidate cell are both controlled by the same DU (eg, the UE does not need to perform a MAC reset when the source cell and the candidate cell are both controlled by the same DU). • Whether both the source cell and the candidate target cell are controlled by the same hardware or software unit.

[0152] In some embodiments, the candidate DU receives an indication from the serving DU or CU as to whether the UE needs to perform a MAC reset when performing L1 / L2 inter-cell mobility to one of the UE's configured L1 / L2 inter-cell mobility candidate cells.

[0153] In some embodiments, the candidate DU sends an indication to the serving DU or CU as to whether the UE needs to perform a MAC reset when performing L1 / L2 inter-cell mobility to one of the UE's configured L1 / L2 inter-cell mobility candidate cells.

[0154] In some embodiments, the candidate DU determines whether the UE needs to perform a MAC reset when performing L1 / L2 inter-cell mobility to the candidate cell and sets the indication accordingly. In various embodiments, the determination is based on one or more of the following: Explicit indication from the serving DU or CU; • Whether the source cell and the candidate cell are both controlled by the same DU (eg, the UE does not need to perform a MAC reset when the source cell and the candidate cell are both controlled by the same DU). • Whether both the source cell and the candidate target cell are controlled by the same hardware or software unit.

[0155] You can refer to Figures 11 to 13 To further illustrate the above embodiment, Figures 11 to 13 Exemplary methods (eg, processes) for a UE, a serving DU, and a candidate DU are depicted, respectively. In other words, various features of the operations described below correspond to the various embodiments described above. Figures 11 to 13 The exemplary methods shown in the can be used in conjunction to provide benefits, advantages and / or solutions to the problems described herein. Figures 11 to 13The exemplary method is shown by specific blocks in a specific order, but the operations corresponding to the blocks can be performed in a different order than shown, and can be combined and / or divided into blocks and / or operations with different functions than shown. Optional blocks or operations are indicated by dotted lines.

[0156] More specifically, Fig.11 An exemplary method (eg, process) for a UE configured to communicate with a RAN node including a CU and a DU providing a serving cell for the UE according to various embodiments of the present disclosure is illustrated. Fig.11 The example methods shown in may be performed by a UE (eg, a wireless device) such as described elsewhere herein.

[0157] The exemplary method may include the operation of box 1150, wherein the UE may receive a low layer signaling message from the DU indicating that the UE should perform L1 / L2 based inter-cell mobility for a first candidate cell provided by the candidate DU. The low layer signaling message includes an indicator or identification of the first candidate cell and an indication of a first TCI state to be used by the UE to communicate with the first candidate cell. The exemplary method may also include the operation of box 1170, wherein the UE may perform an L1 / L2 mobility procedure to the first candidate cell and communicate in the first candidate cell based on the first TCI state.

[0158] In some embodiments, the indication of the first TCI state is a TCI state identifier or an index of a first beam or reference signal (RS) transmitted in a first candidate cell. In some embodiments of these embodiments, the exemplary method may further include operations of blocks 1110 and 1160. In block 1110, the UE may receive an RRCReconfiguration message from the CU via the DU, the RRCReconfiguration message including a configuration associated with one or more candidate cells for L1 / L2-based inter-cell mobility, the one or more candidate cells including a first candidate cell. Each candidate cell configuration includes a plurality of TCI state configurations, and each TCI state configuration includes an index of a beam or RS arranged as a quasi-co-location (QCL) source. In block 1160, the UE may select a TCI state configuration that includes an index of a first beam or RS as a QCL source in the TCI state configuration as the first TCI state.

[0159] In some of these embodiments, the exemplary method may further include the operation of block 1120, wherein the UE may send an RRCReconfigurationComplete message to the CU via the DU in response to the RRCReconfiguration message. In some of these embodiments, one of the following includes an indication of whether the UE should perform a MAC reset when performing L1 / L2 inter-cell mobility to the first candidate cell: configuration for the first candidate cell (e.g., in block 1110), or a message compatible with low layer signaling. In some variations of these embodiments, performing the L1 / L2 mobility procedure to the first candidate cell in block 1170 includes the operation of sub-block 1171, wherein the UE may selectively perform one or more of the following operations based on the indication of whether the UE should perform a MAC reset: Initialize MAC state variables; Stop, start or restart the MAC timer; Reset the New Data Indicator (NDI) for the uplink hybrid ARQ process to zero; Stop the ongoing MAC process; Cancel the triggered but not carried out MAC process; ·Flush the MAC message buffer; Reset the MAC counter; and Release the Radio Network Temporary Identifier (RNTI) allocated to the UE.

[0160] In some embodiments, the low layer signaling message also includes an indication of whether the UE should perform a random access (RA) procedure when performing L1 / L2 inter-cell mobility to the first candidate cell. In some of these embodiments, performing the L1 / L2 mobility procedure to the first candidate cell in block 1170 includes operations of subblock 1172, wherein the UE may selectively perform the RA procedure in the first candidate cell based on one or more of the following: An indication of whether the UE should perform a RA procedure; Whether the time alignment of the first candidate cell is different from the time alignment of the serving cell; Whether the time alignment timer of the first candidate cell has expired; and • Whether the time alignment of the first candidate cell is known or unknown.

[0161] In some embodiments, the exemplary method may further include operations of blocks 1130 to 1140, wherein the UE may perform measurements on multiple beams or RSs occurring in the first candidate cell and send the results of the measurements to the DU. In this case, the first TCI state corresponds to the index of the beam or RS having the measurement result that is most favorable for L1 / L2 mobility for the first candidate cell. In some of these embodiments, the multiple beams or RSs include one or more of: a synchronization signal / PBCH block (SSB) and a channel state information reference signal (CSI-RS).

[0162] In some embodiments, one or more of the following applies: the low layer signaling message is used for a protocol layer below the RRC protocol layer, and the low layer signaling message is one of the following: a MAC control element (CE) or a physical layer downlink control information (DCI). In some embodiments, the candidate DU is associated with a CU and / or is part of a RAN node.

[0163] In some embodiments, communicating in the first candidate cell based on the first TCI state in block 1170 includes one or more of the following operations, represented by corresponding sub-block numbers: (1173) monitoring a downlink control channel of a first candidate cell in a beam or spatial direction corresponding to a first TCI state; (1174) Sending uplink data or a scheduling request to the first candidate cell in a beam or spatial direction corresponding to the first TCI state.

[0164] in addition, Fig.12 An exemplary method (eg, process) for a DU of a RAN node, which is configured to communicate with a CU of the RAN node and provide a serving cell for a UE, is illustrated according to various embodiments of the present disclosure. Fig.12 The illustrated exemplary method may be performed by a service such as a DU as described elsewhere herein.

[0165] The exemplary method may include the operation of box 1250, where the DU may select a first candidate cell provided by the candidate DU for L1 / L2-based inter-cell mobility of the UE served by the DU via the serving cell. The exemplary method may also include the operation of box 1280, where the DU may send a low-layer signaling message to the UE indicating that the UE should perform L1 / L2-based inter-cell mobility on the first candidate cell. The low-layer signaling message includes an indicator or identification of the first candidate cell and an indication of a first TCI state to be used by the UE to communicate with the first candidate cell.

[0166] In some embodiments, the exemplary method may further include the operation of block 1240, wherein the DU may receive from the UE a result of a measurement performed by the UE on a plurality of beams or RSs transmitted in the first candidate cell. The measurement result includes a corresponding index of the plurality of beams or RSs. In some of these embodiments, the plurality of beams or RSs include one or more of: SSB and CSI-RS.

[0167] In some of these embodiments, the first TCI state is associated with a first beam or RS having a measurement result that is most favorable for L1 / L2 mobility for the first candidate cell (e.g., the highest SS-RSRP). In some variations of these embodiments, the indication of the first TCI state is one of: an index of the first beam or RS, or a TCI state identifier.

[0168] In some other variations of these embodiments, the exemplary method may also include the operation of block 1260, where the DU may determine a TCI state identifier for the first TCI state based on: an index of the first beam or RS, which is an indication of the first TCI state; and a mapping between the TCI state identifier used in the first candidate cell and the index of the beam or RS transmitted in the first candidate cell. In some further variations, the exemplary method may also include the operation of block 1205, where the DU may receive a mapping (e.g., used in block 1260) from a candidate DU or CU.

[0169] In some embodiments, the example method may also include the operation of block 1290, where the DU may send a message to the CU or the candidate DU including one or more of the following: An indicator or identity of a first candidate cell for L1 / L2 based inter-cell mobility of the UE; an indication of a first TCI state to be used by the UE to communicate with the first candidate cell; and • A copy or encapsulation of a low layer signaling message (eg, sent or to be sent to the UE in block 1280).

[0170] In some embodiments, the low-layer signaling message in block 1280 may also include one or more of the following: an indication of whether the UE should perform a RA procedure when performing L1 / L2 inter-cell mobility on the first candidate cell; and • An indication of whether the UE should perform a MAC reset when performing L1 / L2 inter-cell mobility to the first candidate cell.

[0171] In some of these embodiments, the exemplary method may further include the operation of block 1270, wherein the DU may determine whether the UE should perform a RA procedure when performing L1 / L2 inter-cell mobility for the first candidate cell as indicated in the lower layer signaling message based on one or more of the following: · Whether the time alignment of the first candidate cell is different from the time alignment of the serving cell; Whether the time alignment timer of the first candidate cell has timed out; and • Whether the time alignment of the first candidate cell is known or unknown.

[0172] In some embodiments, the low layer signaling message is for a protocol layer below the RRC protocol layer and / or the low layer signaling message is a MAC CE or a PHY DCI. Optionally, the candidate DU is associated with a CU and / or is part of a RAN node.

[0173] In some embodiments, the exemplary method may further include performing the following operations by the DU, which are marked with corresponding box numbers: (1210) Sending a request to the CU or candidate DU to configure at least one candidate cell for L1 / L2 based inter-cell mobility to the UE; (1220) receiving, from the CU or the candidate DU, configurations for one or more candidate cells provided by the candidate DU, the one or more candidate cells including a first candidate cell; and (1230) Send the configuration to the UE in an RRCReconfiguration message.

[0174] in addition, Fig.13 Exemplary methods (eg, processes) for candidate DUs of a RAN node according to various embodiments of the present disclosure are illustrated. Fig.13 The illustrated exemplary method may be performed by a candidate DU such as described elsewhere herein.

[0175] The exemplary method may include the operation of box 1320, wherein the candidate DU may receive a request to configure the UE for at least one candidate cell for L1 / L2-based inter-cell mobility from the CU or from the DU serving the UE via the serving cell. The exemplary method may also include the operation of box 1330, wherein the candidate DU may send a configuration for one or more candidate cells provided by the candidate DU to the CU or DU, the one or more candidate cells including a first candidate cell. The exemplary method may also include the operation of box 1340, wherein the candidate DU may receive a message from the DU indicating the L1 / L2 mobility process performed by the UE. The message includes an indicator or identification of a first candidate cell for L1 / L2-based inter-cell mobility of the UE, and an indication of a first TCI state to be used by the UE to communicate with the first candidate cell. The exemplary method may also include the operation of box 1360, wherein the candidate DU may communicate with the UE in the first candidate cell based on the first TCI state.

[0176] In some embodiments, the DU is associated with the CU and / or is part of the RAN node. In some embodiments, the indicator or identification of the first candidate cell and the indication of the first TCI state are received in a copy or encapsulation of a low layer signaling message sent by the DU to the UE.

[0177] In some embodiments, the indication of the first TCI state is an index of a first beam or RS transmitted in the candidate cell. In such an embodiment, the exemplary method may also include the operation of block 1350, where the candidate DU may determine the first TCI state or an identifier thereof based on the index of the first beam or RS, and a mapping between a TCI state identifier used in the first candidate cell and an index of a beam or RS transmitted in the first candidate cell.

[0178] In other embodiments, the indication of the first TCI state is a TCI state identifier, and the exemplary method also includes the operation of box 1310, wherein the candidate DU can send a mapping between the TCI state identifier used in the first candidate cell and the index of the beam or RS sent in the first candidate cell to the CU or DU.

[0179] In some embodiments, the configuration for the first candidate cell (eg, sent in block 1330) includes an indication of whether the UE should perform a MAC reset when performing L1 / L2 inter-cell mobility with the first candidate cell.

[0180] In some embodiments, communicating with the UE in the first candidate cell based on the first TCI state in block 1360 includes one or more of the following operations, represented by corresponding sub-block numbers: (1361) transmitting a downlink control channel of the first candidate cell in a beam or spatial direction corresponding to the first TCI state; and (1362) Receiving uplink data or a scheduling request from a UE in a first candidate cell in a beam or spatial direction corresponding to a first TCI state.

[0181] Although various embodiments are described above in terms of methods, techniques and / or processes, a person of ordinary skill will readily appreciate that such methods, techniques and / or processes may be embodied through various combinations of hardware and software in various systems, communication devices, computing devices, control devices, apparatuses, non-transitory computer-readable media, computer program products, and the like.

[0182] Fig.14 An example of a communication system 1400 according to some embodiments is shown. In this example, the communication system 1400 includes a telecommunications network 1402, which includes an access network 1404 (e.g., RAN) and a core network 1406, which includes one or more core network nodes 1408. The access network 1404 includes one or more access network nodes, such as network nodes 1410a-b (one or more of which may be generally referred to as network nodes 1410) or any other similar 3GPP access nodes or non-3GPP access points. The network nodes 1410 facilitate direct or indirect connection of UEs, such as by connecting UEs 1412a-d (one or more of which may be generally referred to as UEs 1412) to the core network 1406 over one or more wireless connections.

[0183] Example wireless communications over wireless connections include sending and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. In addition, in various embodiments, the communication system 1400 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals via a wired or wireless connection. The communication system 1400 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar types of systems.

[0184] UE 1412 may be any of a variety of communication devices, including wireless devices that are arranged, configured and / or operable to communicate wirelessly with network node 1410 and other communication devices. Similarly, network node 1410 is arranged, capable, configured and / or operable to communicate directly or indirectly with UE 1412 and / or with other network nodes or devices in telecommunication network 1402 to enable and / or provide network access, such as wireless network access, and / or perform other functions, such as management in telecommunication network 1402.

[0185] In the depicted example, the core network 1406 connects the network node 1410 to one or more hosts, such as the host 1416. These connections may be direct or indirect via one or more intermediate networks or devices. In other examples, the network node may be directly coupled to the host. The core network 1406 includes one or more core network nodes (e.g., 1408) constructed with hardware and software components. The features of these components may be substantially similar to those described with respect to the UE, network nodes, and / or hosts, so that their descriptions are generally applicable to the corresponding components of the core network node 1408. The example core network node includes a mobile switching center (MSC), a mobility management entity (MME), a home subscriber server (HSS), an access and mobility management function (AMF), a session management function (SMF), an authentication server function (AUSF), a subscription identifier de-hiding function (SIDF), a unified data management (UDM), a security edge protection agent (SEPP), a network open function (NEF), and / or a user plane function (UPF) One or more functions.

[0186] The host 1416 may be under the ownership or control of a service provider other than the operator or provider of the access network 1404 and / or the telecommunications network 1402, and may be operated by or on behalf of the service provider. The host 1416 may host various applications to provide one or more services. Examples of such applications include live and pre-recorded audio / video content, data collection services (such as retrieving and compiling data about various environmental conditions detected by multiple UEs), analysis functions, social media, functions for controlling or otherwise interacting with remote devices, functions for alarm and monitoring centers, or any other such functions performed by a server.

[0187] As a whole, Fig.14The communication system 1400 enables connections between UEs, network nodes, and hosts. In this sense, the communication system can be configured to operate according to predefined rules or procedures, such as specific standards, including but not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE) and / or other suitable 2G, 3G, 4G, 5G standards or any applicable next generation standards (e.g., 6G); Wireless Local Area Network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard (WiFi); and / or any other suitable wireless communication standards, such as Worldwide Interoperability for Microwave Access (Wi Max), Bluetooth, Z-wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any Low Power Wide Area Network (LPWAN) standards, such as LoRa and Sigfox.

[0188] In some examples, telecommunication network 1402 is a cellular network implementing 3GPP standardized features. Thus, telecommunication network 1402 can support network slicing to provide different logical networks to different devices connected to telecommunication network 1402. For example, telecommunication network 1402 can provide ultra-reliable low-latency communication (URLLC) services to some UEs, while providing enhanced mobile broadband (eMBB) services to other UEs, and / or provide massive machine type communication (mMTC) / massive IoT services to additional UEs.

[0189] In some examples, UE 1412 is configured to send and / or receive information without direct human interaction. For example, the UE can be designed to send information to access network 1404 with a predetermined schedule when triggered by an internal or external event, or in response to a request from access network 1404. In addition, the UE can be configured to operate in a single RAT or multi-RAT or multi-standard mode. For example, the UE can operate with any one or a combination of Wi-Fi, NR (New Radio), and LTE, i.e., be configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved UMTS Terrestrial Radio Access Network) New Radio Dual Connectivity (EN-DC).

[0190] In this example, the hub 1414 communicates with the access network 1404 to facilitate indirect communication between one or more UEs (e.g., UE 1412c and / or 1412d) and a network node (e.g., network node 1410b). In some examples, the hub 1414 can be a controller, a router, a content source and analysis, or any other communication device described herein about the UE. For example, the hub 1414 can be a broadband router that allows the UE to access the core network 1406. As another example, the hub 1414 can be a controller that sends commands or instructions to one or more actuators in the UE. Commands or instructions can be received from the UE, the network node 1410, or through executable code, scripts, processes, or other instructions in the hub 1414. As another example, the hub 1414 can be a data collector that acts as a temporary storage of UE data, and in some embodiments, analysis or other processing of the data can be performed. As another example, the hub 1414 can be a content source. For example, for a UE that is a VR headset, display, speaker, or other media delivery device, the hub 1414 can retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, and then the hub 1414 provides the media or data directly to the UE after performing local processing and / or after adding additional local content. In another example, the hub 1414 acts as a proxy server or coordinator for the UE, particularly when one or more UEs are low-energy IoT devices.

[0191] Hub 1414 can have constant / persistent or intermittent connection to network node 1410b. Hub 1414 can also allow different communication schemes and / or scheduling between hub 1414 and UE (e.g., UE 1412c and / or 1412d) and hub 1414 and core network 1406. In other examples, hub 1414 is connected to core network 1406 and / or one or more UE via wired connection. In addition, hub 1414 can be configured to be connected to M2M service provider and / or connected to another UE via direct connection through access network 1404. In some scenarios, UE can establish wireless connection with network node 1410, while still connected via hub 1414 via wired or wireless connection. In some embodiments, hub 1414 can be a dedicated hub, that is, its main function is to route communication from network node 1410b to UE / from UE to the hub of network node 1410b. In other embodiments, the hub 1414 may be a non-dedicated hub, ie, a device operable to route communications between UEs and the network node 1410b, but also operable as a communications origin and / or destination for certain data channels.

[0192] Fig.15UE 1500 according to some embodiments is shown. Examples of UE include, but are not limited to, smart phones, mobile phones, cellular phones, voice over IP (VoIP) phones, wireless local loop phones, desktop computers, personal digital assistants (PDAs), wireless cameras, game consoles or devices, music storage devices, rechargeable devices, wearable terminal devices, wireless endpoints, mobile stations, tablet computers, laptops, laptop embedded devices (LEEs), laptop mounted devices (LMEs), smart devices, wireless customer equipment (CPEs), in-vehicle or vehicle embedded / integrated wireless devices, etc. Other examples include any UE identified by the Third Generation Partnership Project (3GPP), including narrowband Internet of Things (NB-IoT) UEs, machine type communication (MTC) UEs, and / or enhanced MTC (eMTC) UEs.

[0193] The UE may support device-to-device (D2D) communications, such as by implementing 3GPP standards for sidelink communications, dedicated short-range communications (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the associated device. Instead, a UE may represent a device that is intended to be sold to or operated by a human user but may not be associated with a specific human user (e.g., a smart sprinkler controller) or may not initially be associated with a specific human user. Alternatively, a UE may represent a device that is not intended to be sold to or operated by an end user but may be associated with or operated for the benefit of a user (e.g., a smart meter).

[0194] UE 1500 includes a processing circuit 1502, which is operatively coupled to an input / output interface 1506, a power supply 1508, a memory 1510, a communication interface 1512, and / or any other components or any combination thereof via a bus 1504. Some UEs may utilize Fig.15 All or a subset of the components shown in . The level of integration between components may vary from one UE to another UE. In addition, some UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0195] The processing circuit 1502 is configured to process instructions and data, and may be configured to implement any sequential state machine operable to execute instructions stored in the memory 1510 as a machine-readable computer program. The processing circuit 1502 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors (such as microprocessors or digital signal processors (DSPs)) together with appropriate software; or any combination of the above. For example, the processing circuit 1502 may include multiple central processing units (CPUs).

[0196] In this example, the input / output interface 1506 can be configured to provide one or more interfaces to an input device, an output device, or one or more input and / or output devices. Examples of output devices include speakers, sound cards, video cards, displays, monitors, printers, actuators, transmitters, smart cards, another output device, or any combination thereof. An input device can allow a user to capture information into the UE 1500. Examples of input devices include touch-sensitive or presence-sensitive displays, cameras (e.g., digital cameras, digital video cameras, web cameras, etc.), microphones, sensors, mice, trackballs, direction pads, trackpads, scroll wheels, smart cards, etc. A presence-sensitive display can include a capacitive or resistive touch sensor to sense input from a user. The sensor can be, for example, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device can use an interface port of the same type as an input device. For example, a universal serial bus (USB) port can be used to provide input devices and output devices.

[0197] In some embodiments, the power supply 1508 is configured as a battery or a battery pack. Other types of power supplies may be used, such as an external power supply (e.g., a power outlet), a photovoltaic device, or a battery. The power supply 1508 may also include a power circuit for delivering power from the power supply 1508 itself and / or an external power supply to various parts of the UE 1500 via an input circuit or an interface such as a power cable. For example, the delivered power may be used to charge the power supply 1508. The power circuit may perform any formatting, conversion, or other modification to the power from the power supply 1508 so that the power is suitable for the corresponding components of the UE 1500 to which the power is supplied.

[0198] The memory 1510 may be or be configured to include a memory such as a random access memory (RAM), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a magnetic disk, an optical disk, a hard disk, a removable cartridge, a flash drive, etc. In one example, the memory 1510 includes one or more application programs 1514 (such as an operating system, a web browser application, a widget, a gadget engine, or other applications), and corresponding data 1516. The memory 1510 may store any of a variety of operating systems or a combination of operating systems for use by the UE 1500.

[0199] The memory 1510 may be configured to include a plurality of physical drive units, such as a redundant array of independent disks (RAID), a flash memory, a USB flash drive, an external hard drive, a thumb drive, a pen drive, a key drive, a high-density digital versatile disk (HD-DVD) optical drive, an internal hard drive, a Blu-ray optical drive, a holographic digital data storage (HDDS) optical drive, an external micro dual in-line memory module (DIMM), a synchronous dynamic random access memory (SDRAM), an external micro DIMM SDRAM, a smart card memory (such as a tamper-proof module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs) such as USIM and / or ISIM), other memories, or any combination thereof. The UICC may be, for example, an embedded UICC (eUICC), an integrated UICC (iUICC), or a removable UICC commonly referred to as a “SIM card”. The memory 1510 may allow the UE 1500 to access instructions, applications, etc. stored on a temporary or non-temporary memory medium, to offload data, or to upload data. An article of manufacture such as utilizing a communication system may be tangibly embodied as or in memory 1510 , which may be or include a device-readable storage medium.

[0200] The processing circuit 1502 may be configured to communicate with an access network or other network using a communication interface 1512. The communication interface 1512 may include one or more communication subsystems and may include or be communicatively coupled to an antenna 1522. The communication interface 1512 may include one or more transceivers for communication, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 1518 and / or a receiver 1520 suitable for providing network communications (e.g., optical, electrical, frequency allocation, etc.). In addition, the transmitter 1518 and the receiver 1520 may be coupled to one or more antennas (e.g., 1522) and may share circuit components, software, or firmware, or may be implemented separately instead.

[0201] In the illustrated embodiment, the communication functions of the communication interface 1512 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communication such as Bluetooth, near field communication, location-based communication such as using a global positioning system (GPS) to determine location, another similar communication function, or any combination thereof. The communication may be implemented according to one or more communication protocols and / or standards, such as IEEE 802.11, code division multiple access (CDMA), wideband code division multiple access (WCDMA), GSM, LTE, new radio (NR), UMTS, WiMax, Ethernet, transmission control protocol / Internet protocol (TCP / IP), synchronous optical networking (SONET), asynchronous transfer mode (ATM), QUIC, hypertext transfer protocol (HTTP), etc.

[0202] Regardless of the type of sensor, the UE may provide an output of the data captured by its sensor via a wireless connection to a network node through its communication interface 1512. The data captured by the UE's sensor may be transmitted to the network node via another UE over a wireless connection. The output may be periodic (e.g., once every 15 minutes if it reports a sensed temperature), random (e.g., to even out the load from reports from several sensors), in response to a trigger event (e.g., sending an alarm when moisture is detected), in response to a request (e.g., a user-initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0203] As another example, the UE includes an actuator, motor, or switch associated with a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input, the state of the actuator, motor, or switch can change. For example, the UE can include a motor that adjusts a control surface or rotor of a drone in flight based on the received input, or adjusts a robotic arm performing a medical procedure based on the received input.

[0204] When in the form of an Internet of Things (IoT) device, a UE may be a device for use in one or more application domains including, but not limited to, urban wearable technology, extended industrial applications, and healthcare. Non-limiting examples of such IoT devices are devices embedded in: a connected refrigerator or freezer, a TV, connected lighting, an electric meter, a robotic vacuum cleaner, a voice-controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system (such as a heat pump), an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for augmented reality (AR) or virtual reality (VR), a wearable device for tactile enhancement or sensory enhancement, a sprinkler, an animal or item tracking device, a sensor for monitoring plants or animals, an industrial robot, an unmanned aerial vehicle (UAV), and any kind of medical device (such as a heart rate monitor or a remotely controlled surgical robot). UEs in the form of IoT devices include, in addition to the following: Fig.15 The illustrated UE 1500 may include, among other components depicted, circuitry and / or software depending on the intended application of the IoT device.

[0205] As yet another specific example, in an IoT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements and transmits the results of such monitoring and / or measurements to another UE and / or a network node. In this case, the UE may be an M2M device, which may be referred to as an MTC device in the 3GPP context. As a specific example, a UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, bus, truck, ship, and airplane, or other equipment capable of monitoring and / or reporting its operating status or other functions associated with its operation.

[0206] In fact, any number of UEs may be used together with respect to a single use case. For example, a first UE may be a drone or integrated in a drone and provide speed information of the drone (obtained by a speed sensor) to a second UE that is a remote controller operating the drone. When a user makes a change from the remote controller, the first UE may adjust the throttle on the drone (e.g., by controlling an actuator) to increase or decrease the speed of the drone. The first and / or second UE may also include more than one of the above functions. For example, a UE may include a sensor and an actuator and handle data communications for both the speed sensor and the actuator.

[0207] Fig.16A network node 1600 according to some embodiments is shown. Examples of network nodes include, but are not limited to, access points (e.g., radio access points) and base stations (e.g., radio base stations, Node Bs, eNBs, and gNBs).

[0208] Base stations may be classified based on the amount of coverage they provide (or in other words, their transmit power level), and may therefore be referred to as femto base stations, pico base stations, micro base stations, or macro base stations, depending on the amount of coverage provided. A base station may be a relay node or a relay donor node that controls a relay. A network node may also include one or more (or all) parts of a distributed radio base station, such as a centralized digital unit and / or a remote radio unit (RRU), sometimes referred to as a remote radio head (RRH). Such a remote radio unit may or may not be integrated with an antenna as an antenna-integrated radio. Portions of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0209] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as an MSR BS, a network controller such as a radio network controller (RNC) or a base station controller (BSC), a base transceiver station (BTS), a transmission point, a transmission node, a multi-cell / multicast coordination entity (MCE), an operation and maintenance (O&M) node, an operation support system (OSS) node, a self-organizing network (SON) node, a positioning node (e.g., an evolved serving mobile location center (E-SLC)), and / or minimization of drive tests (MDT).

[0210] The network node 1600 includes a processing circuit 1602, a memory 1604, a communication interface 1606, and a power supply 1608. The network node 1600 may be composed of multiple physically separated components (e.g., a B node component and an RNC component, or a BTS component and a BSC component, etc.), each of which may have its own corresponding components. In certain scenarios where the network node 1600 includes multiple separate components (e.g., BTS and BSC components), one or more separate components may be shared between several network nodes. For example, a single RNC may control multiple B nodes. In such scenarios, each unique B node and RNC pair may be considered as a single separate network node in some instances. In some embodiments, the network node 1600 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memories 1604 for different RATs), and some components may be reused (e.g., the same antenna 1610 may be shared by different RATs). The network node 1600 may also include multiple sets of various illustrated components for different wireless technologies (e.g., GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, radio frequency identification (RFID), or Bluetooth wireless technologies) integrated into the network node 1600. These wireless technologies may be integrated into the same or different chips or chipsets and other components within the network node 1600.

[0211] The processing circuit 1602 may include a combination of one or more of a microprocessor, a controller, a microcontroller, a central processing unit, a digital signal processor, an application specific integrated circuit, a field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic that is operable to provide network node 1600 functionality alone or in conjunction with other network node 1600 components (such as memory 1604).

[0212] In some embodiments, processing circuitry 1602 includes a system on a chip (SOC). In some embodiments, processing circuitry 1602 includes one or more of radio frequency (RF) transceiver circuitry 1612 and baseband processing circuitry 1614. In some embodiments, RF transceiver circuitry 1612 and baseband processing circuitry 1614 may be on separate chips (or chipsets), boards, or units (such as a radio unit and a digital unit). In alternative embodiments, part or all of RF transceiver circuitry 1612 and baseband processing circuitry 1614 may be on the same chip or a set of chips, boards, or units.

[0213] The memory 1604 may include any form of volatile or non-volatile computer-readable memory, including but not limited to persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (e.g., hard disk), removable storage media (e.g., flash drive, compact disk (CD) or digital video disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computer-executable memory device that stores information, data and / or instructions that can be used by the processing circuit 1602. The memory 1604 may store any suitable instructions, data or information, including computer programs, software, applications including one or more of logic, rules, codes, tables and / or other instructions that can be executed by the processing circuit 1602 and utilized by the network node 1600 (collectively referred to as computer programs 1604a, which may be in the form of a computer program product). The memory 1604 may be used to store any calculations performed by the processing circuit 1602 and / or any data received via the communication interface 1606. In some embodiments, processing circuit 1602 and memory 1604 are integrated.

[0214] The communication interface 1606 is used for wired or wireless communication of signaling and / or data between network nodes, access networks and / or UEs. As shown in the figure, the communication interface 1606 includes a port / terminal 1616 for sending data to the network and receiving data from the network via a wired connection. The communication interface 1606 also includes a radio front-end circuit 1618, which can be coupled to an antenna 1610 or to a part of an antenna 1610 in some embodiments. The radio front-end circuit 1618 includes a filter 1620 and an amplifier 1622. The radio front-end circuit 1618 can be connected to the antenna 1610 and the processing circuit 1602. The radio front-end circuit can be configured to adjust the signal transmitted between the antenna 1610 and the processing circuit 1602. The radio front-end circuit 1618 can receive digital data to be sent to other network nodes or UEs via a wireless connection. The radio front-end circuit 1618 can use a combination of a filter 1620 and / or an amplifier 1622 to convert the digital data into a radio signal with appropriate channel and bandwidth parameters. The radio signal can then be sent via the antenna 1610. Similarly, when receiving data, antenna 1610 may collect radio signals, which are then converted into digital data by radio front end circuit 1618. The digital data may be passed to processing circuit 1602. In other embodiments, the communication interface may include different components and / or different combinations of components.

[0215] In certain alternative embodiments, the network node 1600 does not include a separate radio front end circuit 1618, but rather the processing circuit 1602 includes the radio front end circuit and is connected to the antenna 1610. Similarly, in some embodiments, all or some of the RF transceiver circuit 1612 is part of the communication interface 1606. In other embodiments, the communication interface 1606 includes one or more ports or terminals 1616, the radio front end circuit 1618, and the RF transceiver circuit 1612 as part of a radio unit (not shown), and the communication interface 1606 communicates with the baseband processing circuit 1614 as part of a digital unit (not shown).

[0216] Antenna 1610 may include one or more antennas or antenna arrays configured to send and / or receive wireless signals. Antenna 1610 may be coupled to radio front end circuit 1618 and may be any type of antenna capable of wirelessly sending and receiving data and / or signals. In some embodiments, antenna 1610 is separate from network node 1600 and may be connected to network node 1600 via an interface or port.

[0217] Antenna 1610, communication interface 1606 and / or processing circuit 1602 may be configured to perform any receiving operation and / or certain obtaining operations described herein as being performed by a network node. Any information, data and / or signal may be received from a UE, another network node and / or any other network device. Similarly, antenna 1610, communication interface 1606 and / or processing circuit 1602 may be configured to perform any sending operation described herein as being performed by a network node. Any information, data and / or signal may be sent to a UE, another network node and / or any other network device.

[0218] The power supply 1608 provides power to the various components of the network node 1600 in a form suitable for the respective components (e.g., at the voltage and current levels required by each respective component). The power supply 1608 may also include or be coupled to a power management circuit to provide power to the components of the network node 1600 to perform the functions described herein. For example, the network node 1600 may be connected to an external power source (e.g., an electrical grid, a power outlet) via an input circuit or interface such as a cable, whereby the external power source provides power to the power circuit of the power supply 1608. As another example, the power supply 1608 may include a power source in the form of a battery or battery pack that is connected to or integrated in the power circuit. If the external power source fails, the battery may provide backup power.

[0219] Embodiments of the network node 1600 may include, in addition to Fig.16Additional components beyond those shown are used to provide certain aspects of the functionality of the network node, including any functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 1600 may include a user interface device to allow information to be input into the network node 1600 and to allow information to be output from the network node 1600. This may allow a user to perform diagnostics, maintenance, repair, and other management functions of the network node 1600.

[0220] Fig.17 is a block diagram of a host 1700 according to various aspects described herein, which host 1700 may be Fig.14 1416 of the embodiment of the host. As used herein, the host 1700 can be or include various combinations of hardware and / or software, including processing resources in a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, a container, or a server cluster. The host 1700 can provide one or more services to one or more UEs.

[0221] Host 1700 includes processing circuitry 1702 operatively coupled to input / output interface 1706, network interface 1708, power supply 1710, and memory 1712 via bus 1704. Other components may be included in other embodiments. The features of these components may be substantially similar to those described with respect to previous figures (such as FIG. Fig.15 and 16 ) so that its description is generally applicable to corresponding components of host 1700.

[0222] Memory 1712 may include one or more computer programs, including one or more host applications 1714 and data 1716, which may include user data, such as data generated by the UE for the host 1700 or data generated by the host 1700 for the UE. An embodiment of the host 1700 may utilize only a subset or all of the components shown. The host application 1714 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), MPEG, VP9) and audio codecs (e.g., FLAC, Advanced Audio Coding (AAC), MPEG, G). 711)-including transcoding for multiple different categories, types or implementations of UE (e.g., mobile phones, desktop computers, wearable display systems, head-up display systems). The host application 1714 may also provide user authentication and license checks, and may periodically report health, routing, and content availability to a central node (such as a device in or on the edge of a core network). Thus, the host 1700 may select and / or indicate a different host for an over-the-top service for the UE. The host application 1714 may support various protocols, such as HTTP Live Streaming (HLS) protocol, Real-Time Messaging Protocol (RTMP), Real-Time Streaming Protocol (RTSP), HTTP Dynamic Adaptive Streaming (MPEG-DASH), etc.

[0223] Fig.18 It is a block diagram showing a virtualized environment 1800 in which the functions implemented by some embodiments can be virtualized. In this context, virtualization means creating a virtual version of a device or equipment, which may include a virtualized hardware platform, storage device, and network resources. As used herein, virtualization can be applied to any device described herein or its components, and relates to the implementation in which at least a portion of the functions are implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components performed by one or more virtual machines (VMs), which are implemented in one or more virtual environments 1800 hosted by one or more hardware nodes, such as hardware computing devices operated as network nodes, UEs, core network nodes, or hosts. In addition, in embodiments where the virtual node does not require a radio connection (e.g., a core network node or a host), the node may be fully virtualized.

[0224] Application 1802 (which may alternatively be referred to as a software instance, a virtual appliance, a network function, a virtual node, a virtual network function, etc.) runs in a virtualized environment 1800 to implement some features, functions and / or benefits of some embodiments disclosed herein.

[0225] The hardware 1804 includes processing circuitry, memory storing software and / or instructions (collectively referred to as computer program 1804a, which may be in the form of a computer program product) executable by the hardware processing circuitry, and / or other hardware devices as described herein, such as network interfaces, input / output interfaces, etc. The software may be executed by the processing circuitry to instantiate one or more virtualization layers 1806 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 1808a-b (one or more of which may be generally referred to as VMs 1808), and / or perform any of the functions, features, and / or benefits described with respect to some embodiments described herein. The virtualization layer 1806 may present a virtual operating platform that looks like networked hardware to the VMs 1808.

[0226] VM 1808 includes virtual processing, virtual memory, virtual networking or interfaces, and virtual storage, and may be run by a corresponding virtualization layer 1806. Different embodiments of virtual devices 1802 may be implemented on one or more VMs 1808, and may be implemented in different ways. Virtualization of hardware is referred to in some contexts as network function virtualization (NFV). NFV may be used to merge many network device types onto industry standard high-capacity server hardware, physical switches, and physical storage, which may be in data centers and customer premises equipment.

[0227] In the context of NFV, each VM 1808 can be a software implementation of a physical machine running programs, as if they were executed on a physical non-virtualized machine. Each VM 1808 and the portion of the hardware 1804 on which the VM is executed, i.e., the hardware dedicated to the VM and / or the hardware shared by the VM with other VMs, form a separate virtual network element. Still in the context of NFV, a virtual network function is responsible for handling a specific network function running in one or more VMs 1808 on top of the hardware 1804 and corresponding to an application 1802.

[0228] Hardware 1804 may be implemented in a standalone network node with general or specific components. Hardware 1804 may implement some functions via virtualization. Alternatively, hardware 1804 may be part of a larger hardware cluster (e.g., such as in a data center or CPE), where many hardware nodes work together and are managed via management and orchestration 1810, which in particular oversees the lifecycle management of application 1802. In some embodiments, hardware 1804 is coupled to one or more radio units, each of which includes one or more transmitters and one or more receivers that may be coupled to one or more antennas. The radio unit may communicate directly with other hardware nodes via one or more appropriate network interfaces, and may be used in combination with virtual components to provide a virtual node with radio capabilities, such as a radio access node or base station. In some embodiments, a control system 1812 may be used to provide some signaling, which may be used alternatively for communication between hardware nodes and radio units.

[0229] Fig.19 A communication diagram of a host 1902 communicating with a UE 1906 via a network node 1904 over a partially wireless connection according to some embodiments. Fig.19 Describes the UE discussed in the preceding paragraphs (such as Fig.14 UE 1412a and / or Fig.15 UE 1500), network nodes (such as Fig.14 The network node 1410a and / or Fig.16 network nodes 1600) and hosts (such as Fig.14 Host 1416 and / or Fig.17 An example implementation of host 1700).

[0230] Similar to the host 1700, an embodiment of the host 1902 includes hardware, such as a communication interface, a processing circuit, and a memory. The host 1902 also includes software stored in or accessible by the host 1902 and executable by the processing circuit. The software includes a host application operable to provide services to a remote user, such as a UE 1906 connected via an over-the-top (OTT) connection 1950 extending between the UE 1906 and the host 1902. When providing services to the remote user, the host application can provide user data sent using the OTT connection 1950.

[0231] The network node 1904 includes hardware that enables it to communicate with the host 1902 and the UE 1906. The connection 1960 can be direct or through a core network (such as Fig.14The core network 1406 of the present invention) and / or one or more other intermediate networks, such as one or more public, private or managed networks. For example, the intermediate network can be a backbone network or the Internet.

[0232] UE 1906 includes hardware and software, which is stored in UE 1906 or accessible by UE 1906 and can be executed by UE processing circuitry. The software includes a client application, such as a web browser or an operator-specific "app", which is operable to provide services to human or non-human users via UE 1906 with the support of host 1902. In host 1902, the execution host application can communicate with the execution client application via an OTT connection 1950 terminated at UE 1906 and host 1902. When providing services to the user, the client application of the UE can receive request data from the host application of the host and provide user data in response to the request data. The OTT connection 1950 can transmit both request data and user data. The client application of the UE can interact with the user to generate user data that it provides to the host application via the OTT connection 1950.

[0233] The OTT connection 1950 may extend via a connection 1960 between the host 1902 and the network node 1904 and via a wireless connection 1970 between the network node 1904 and the UE 1906 to provide a connection between the host 1902 and the UE 1906. The connection 1960 and the wireless connection 1970 through which the OTT connection 1950 may be provided have been drawn abstractly to illustrate communications between the host 1902 and the UE 1906 via the network node 1904 without explicit reference to any intermediate devices and the precise routing of messages via those devices.

[0234] As an example of transmitting data via OTT connection 1950, in step 1908, host 1902 provides user data, which can be performed by executing a host application. In some embodiments, the user data is associated with a specific human user interacting with UE 1906. In other embodiments, the user data is associated with UE 1906, and UE 1906 shares data with host 1902 without explicit human interaction. In step 1910, host 1902 initiates a transmission carrying user data to UE 1906. Host 1902 may initiate the transmission in response to a request sent by UE 1906. The request may be caused by human interaction with UE 1906 or by operation of a client application executed on UE 1906. According to the teachings of the embodiments described throughout the present disclosure, the transmission may be delivered via network node 1904. Therefore, according to the teachings of the embodiments described throughout the present disclosure, in step 1912, network node 1904 sends the user data carried in the transmission initiated by host 1902 to UE 1906. In step 1914 , UE 1906 receives the user data carried in the transmission, which may be performed by a client application executing on UE 1906 that is associated with a host application executed by host 1902 .

[0235] In some examples, UE 1906 executes a client application that provides user data to host 1902. The user data may be provided as a reaction or response to data received from host 1902. Thus, in step 1916, UE 1906 may provide the user data, which may be performed by executing the client application. In providing the user data, the client application may also take into account user input received from a user via an input / output interface of UE 1906. Regardless of the specific manner in which the user data is provided, UE 1906 initiates transmission of the user data to host 1902 via network node 1904 in step 1918. In step 1920, in accordance with the teachings of the embodiments described throughout the present disclosure, network node 1904 receives user data from UE 1906 and initiates transmission of the received user data toward host 1902. In step 1922, host 1902 receives the user data carried in the transmission initiated by UE 1906.

[0236] One or more of the various embodiments improve the performance of an OTT service provided to a UE 1906 using an OTT connection 1950, with a wireless connection 1970 forming the final segment. More specifically, since the execution phase is separated from the preparation phase, the embodiments described herein can facilitate the execution of L1 / L2 inter-cell mobility much faster than the existing L3-based inter-cell mobility, so that the timing of the low-layer signaling that triggers the execution of the L1 / L2 inter-cell mobility depends on the judgment of the source DU. The advantages are achieved by providing the UE with a TCI state ID or SSB index for a candidate cell in the low-layer signaling that triggers the execution of the L1 / L2 inter-cell mobility, which facilitates timely UE communication with the candidate cell. In addition, by providing the UE with an indication of whether the UE should perform a MAC reset in conjunction with the L1 / L2 inter-cell mobility, the embodiments avoid data loss and excessive interruption when the MAC reset is unnecessary. At a high level, the embodiments improve mobility in a RAN (e.g., NG-RAN). By improving the operation of the UE and the RAN in this way, the embodiments increase the value of the OTT services delivered to / from the UE via the RAN.

[0237] In an example scenario, plant status information may be collected and analyzed by host 1902. As another example, host 1902 may process audio and video data that may have been retrieved from a UE for use in creating a map. As another example, host 1902 may collect and analyze real-time data to help control vehicle congestion (e.g., control traffic lights). As another example, host 1902 may store surveillance videos uploaded by a UE. In another example, host 1902 may store or control access to media content (e.g., video, audio, VR, or AR that may be broadcast, multicast, or unicast to a UE). As other examples, host 1902 may be used for energy pricing, remote control of non-time-critical electrical loads to balance power generation demand, location services, presentation services (such as compiling maps of data collected from remote devices, etc.), or any other function for collecting, retrieving, storing, analyzing, and / or transmitting data.

[0238] In some examples, a measurement process may be provided for the purpose of monitoring data rates, delays, and other factors that are improved by one or more embodiments. In response to changes in the measurement results, there may also be an optional network function for reconfiguring the OTT connection 1950 between the host 1902 and the UE 1906. The measurement process and / or network function for reconfiguring the OTT connection may be implemented in the software and hardware of the host 1902 and / or the UE 1906. In some embodiments, sensors (not shown) may be deployed in or associated with other devices through which the OTT connection 1950 passes; the sensors may participate in the measurement process by providing the values ​​of the monitoring quantities exemplified above or providing the values ​​of other physical quantities from which the software can calculate or estimate the monitoring quantities. Reconfiguring the OTT connection 1950 may include message formats, retransmission settings, preferred routes, etc.; reconfiguration does not require direct changes to the operation of the network node 1904. Such processes and functions may be known and practiced in the art. In some embodiments, the measurement may involve proprietary UE signaling that facilitates the host 1902 to measure throughput, propagation time, latency, etc. Measurements can be made because the software enables sending messages, particularly empty or "dummy" messages, using the OTT connection 1950 while monitoring propagation times, errors, etc.

[0239] The above merely illustrates the principles of the present invention. Various modifications and changes to the described embodiments will be apparent to those skilled in the art with reference to the teachings herein. Therefore, it should be understood that those skilled in the art will be able to design many systems, arrangements, and processes that, although not explicitly shown or described herein, embody the principles of the present disclosure and therefore can be within the spirit and scope of the present disclosure. As will be appreciated by those of ordinary skill in the art, the various embodiments can be used together with each other, and can be used interchangeably therewith.

[0240] As used herein, the term unit may have a conventional meaning in the field of electronic devices, electrical equipment and / or electronic equipment, and may include, for example, electrical and / or electronic circuits, devices, modules, processors, memories, logical solid-state and / or discrete devices, computer programs or instructions for performing corresponding tasks, processes, calculations, output and / or display functions, etc., such as those described herein.

[0241] Any suitable steps, methods, features, functions or benefits disclosed herein can be performed by one or more functional units or modules of one or more virtual devices. Each virtual device may include a plurality of these functional units. These functional units may be implemented via a processing circuit, which may include one or more microprocessors or microcontrollers, and other digital hardware that may include a digital signal processor (DSP), dedicated digital logic, etc. The processing circuit may be configured to execute program codes stored in a memory, which may include one or more types of memory, such as a read-only memory (ROM), a random access memory (RAM), a cache memory, a flash memory device, an optical storage device, etc. The program code stored in the memory includes program instructions for executing one or more telecommunications and / or data communication protocols and instructions for executing one or more technologies described herein. In some embodiments, the processing circuit may be used to cause each functional unit to perform the corresponding functions according to one or more embodiments of the present disclosure.

[0242] As described herein, the device and / or apparatus may be represented by a semiconductor chip, a chipset, or a (hardware) module including such a chip or chipset; however, this does not exclude the possibility that the functions of the device or apparatus (rather than being implemented by hardware) are implemented as software modules such as computer programs or computer program products, which include executable software code portions for execution or operation on a processor. In addition, the functions of the device or apparatus may be implemented by any combination of hardware and software. The device or apparatus may also be viewed as a component of a plurality of devices and / or apparatuses, whether functionally cooperating with each other or independent. In addition, the device and apparatus may be implemented in a distributed manner throughout the system, as long as the functions of the device or apparatus are retained. Such and similar principles are considered to be known to the technician.

[0243] In addition, the functions described herein as being performed by a wireless device or network node may be distributed across multiple wireless devices and / or network nodes. In other words, it is contemplated that the functions of the network nodes and wireless devices described herein are not limited to the performance of a single physical device and may in fact be distributed across several physical devices.

[0244] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. It should also be understood that the terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art, and will not be interpreted in an idealized or overly formal sense unless explicitly defined as such herein.

[0245] In addition, certain terms used in this disclosure (including the specification and the drawings) may be used synonymously in certain circumstances (e.g., "data" and "information"). It should be understood that although these terms (and / or other terms that may be synonymous with each other) may be used synonymously herein, there may be circumstances where such words may not be intended to be used synonymously.

[0246] The techniques and devices described herein include, but are not limited to, the following examples:

[0247] A1. A method for a user equipment (UE), the UE being configured to communicate with a radio access network (RAN) node, the RAN node comprising a central unit (CU) and a distributed unit (DU) providing a serving cell for the UE, the method comprising: Receiving a low layer signaling message from the DU, the low layer signaling message indicating that the UE should perform L1 / L2 based inter-cell mobility on a first candidate cell provided by the candidate DU, wherein the low layer signaling message includes: an indicator or identification of the first candidate cell, and an indication of a first transmission configuration indicator (TCI) state to be used by the UE to communicate with the first candidate cell; An L1 / L2 mobility procedure is performed toward a first candidate cell, and communication is performed in the first candidate cell based on a first TCI state.

[0248] A2. The method of embodiment A1, wherein the indication of the first TCI state is a TCI state identifier.

[0249] A3. A method according to embodiment A1, wherein the indication of the first TCI state is an index of the first beam or reference signal (RS) sent in the first candidate cell.

[0250] A4. The method according to embodiment A3, further comprising: receiving, via the DU, from the CU an RRCReconfiguration message, the RRCReconfiguration message including a configuration associated with one or more candidate cells for L1 / L2 based inter-cell mobility, the one or more candidate cells including a first candidate cell, wherein: Each candidate cell configuration includes multiple TCI state configurations, and Each TCI state configuration includes an index of a beam or RS arranged as a quasi co-located (QCL) source; and A TCI state configuration including an index of a first beam or RS as a QCL source among the TCI state configurations is selected as a first TCI state.

[0251] A5. The method according to embodiment A4 further includes: in response to the RRCReconfiguration message, sending an RRCReconfigurationComplete message to the CU via the DU.

[0252] A5a. The method of any one of embodiments A4 to A5, wherein the configuration for the first candidate cell includes an indication of whether the UE should perform a medium access control (MAC) reset when performing L1 / L2 inter-cell mobility to the first candidate cell.

[0253] A6. The method according to any one of embodiments A1 to A5a, wherein the method further comprises: performing measurement on a plurality of beams or reference signals RS transmitted in a first candidate cell; and Send the measurement results to DU, The first TCI state corresponds to the index of the beam or RS having the measurement result that is most beneficial to the L1 / L2 mobility of the first candidate cell.

[0254] A6a. A method according to embodiment A6, wherein the multiple beams or RSs include one or more of the following: a synchronization signal / PBCH block (SSB) and a channel state information reference signal (CSI-RS).

[0255] A7. A method according to any one of embodiments A1 to A6, wherein the low-layer signaling message further includes one or more of the following: an indication of whether the UE should perform a random access (RA) procedure when performing L1 / L2 inter-cell mobility to the first candidate cell; and An indication of whether the UE should perform a Medium Access Control (MAC) reset when performing L1 / L2 inter-cell mobility to the first candidate cell.

[0256] A8. The method of embodiment A7, wherein performing the L1 / L2 mobility procedure to the first candidate cell comprises selectively performing one or more of the following operations based on an indication of whether the UE should perform a MAC reset: Initialize MAC state variables; Stop, start or restart the MAC timer; Resetting the New Data Indicator (NDI) for the uplink hybrid ARQ process to zero; Stop the ongoing MAC process; Cancel the MAC process that has been triggered but not carried out; Refresh MAC message buffer; Reset the MAC counter; and The radio network temporary identifier RNTI allocated to the UE is released.

[0257] A9. The method of any one of embodiments A7 to A8, wherein performing the L1 / L2 mobility procedure to the first candidate cell comprises selectively performing the RA procedure in the first candidate cell based on one or more of the following: An indication of whether the UE should perform the RA procedure; whether the time alignment of the first candidate cell is different from the time alignment of the serving cell; whether the time alignment timer of the first candidate cell has expired; and The time alignment of the first candidate cell is known or unknown.

[0258] A10. The method according to any one of embodiments A1 to A9, wherein one or more of the following apply: The low layer signaling messages are used for protocol layers below the radio resource control (RRC) protocol layer; and The low layer signaling message is one of the following: MAC CE or PHY DCI.

[0259] A11. The method according to any one of embodiments A1 to A10, wherein communicating in the first candidate cell based on the first TCI state comprises one or more of the following: Monitoring a downlink control channel of a first candidate cell in a beam or spatial direction corresponding to a first TCI state; and Send uplink data or a scheduling request to the first candidate cell in a beam or spatial direction corresponding to the first TCI state.

[0260] A12. The method of any one of embodiments A1 to A11, wherein the candidate DU is associated with a CU and / or is part of a RAN node.

[0261] B1. A method for a distributed unit (DU) of a radio access network (RAN) node, the DU being coupled to a central unit (CU) of the RAN node and being configured to provide a serving cell for a user equipment (UE), the method comprising: selecting a first candidate cell provided by the candidate DU for L1 / L2 based inter-cell mobility of the UE served by the DU via the serving cell; Sending a low layer signaling message to the UE indicating that the UE should perform L1 / L2 based inter-cell mobility on the first candidate cell, the low layer signaling message including: an indicator or identification of the first candidate cell, and An indication of a first transmission configuration indicator (TCI) state to be used by the UE to communicate with the first candidate cell.

[0262] B2. The method according to embodiments A1 to A5a further includes: receiving from the UE the results of measurements performed by the UE on multiple beams or reference signals (RS) sent in the first candidate cell, wherein the measurement results include corresponding indexes of the multiple beams or RSs.

[0263] B2a. A method according to embodiment B2, wherein the multiple beams or RSs include one or more of the following: a synchronization signal / PBCH block (SSB) and a channel state information reference signal (CSI-RS).

[0264] B3. A method according to any one of embodiments B2 to B2a, wherein the first TCI state is associated with a first beam or RS having a measurement result that is most favorable for L1 / L2 mobility for the first candidate cell.

[0265] B4. A method according to embodiment B3, wherein the indication of the first TCI state is an index of the first beam or RS.

[0266] B5. A method according to embodiment B3, wherein the indication of the first TCI state is a TCI state identifier.

[0267] B6. The method according to embodiment B5 also includes: determining a TCI state identifier for the first TCI state based on an index of the first beam or RS and a mapping between the TCI state identifier used in the first candidate cell and an index of the beam or RS sent in the first candidate cell.

[0268] B7. The method according to embodiment B6 also includes receiving a mapping from one of the following: a candidate DU or a CU.

[0269] B8. The method according to any one of embodiments B1 to B7, further comprising: sending a message including one or more of the following to the CU or to the candidate DU: An indicator or identification of a first candidate cell for L1 / L2 based inter-cell mobility of a UE; an indication of a first TCI state to be used by the UE to communicate with the first candidate cell; and A copy or encapsulation of a low-layer signaling message.

[0270] B9. The method according to any one of embodiments B1 to B8, wherein the low-layer signaling message further includes one or more of the following: an indication of whether the UE should perform a random access (RA) procedure when performing L1 / L2 inter-cell mobility to the first candidate cell; and An indication of whether the UE should perform a Medium Access Control (MAC) reset when performing L1 / L2 inter-cell mobility to the first candidate cell.

[0271] B10. The method according to embodiment B9 further includes: determining whether the UE should perform the RA procedure when performing L1 / L2 inter-cell mobility for the first candidate cell as indicated in the low layer signaling message based on one or more of the following: whether the time alignment of the first candidate cell is different from the time alignment of the serving cell; Whether the time alignment timer of the first candidate cell has expired; The time alignment of the first candidate cell is known or unknown.

[0272] B11. The method according to any one of embodiments B1 to B10, wherein one or more of the following apply: The low-layer signaling messages are used for protocol layers below the radio resource control (RRC) protocol layer; The low-layer signaling message is one of the following: MAC CE, PHY DCI.

[0273] B12. The method of any one of embodiments B1 to B11, wherein the candidate DU is associated with a CU and / or is part of a RAN node.

[0274] B13. The method according to any one of embodiments B1 to B12, further comprising: Sending a request to the CU or candidate DU to configure at least one candidate cell for L1 / L2 based inter-cell mobility to the UE; receiving, from the CU or the candidate DU, a configuration for one or more candidate cells provided by the candidate DU, the one or more candidate cells including a first candidate cell; and The configuration is sent to the UE in an RRCReconfiguration message.

[0275] C1. A method for a candidate distributed unit (DU) of a radio access network (RAN) node, the candidate DU being coupled to a central unit (CU) of the RAN node, the method comprising: receiving, from the CU or from the DU currently serving the UE via the serving cell, a request to configure, to the UE, at least one candidate cell for L1 / L2 based inter-cell mobility; sending, to the CU or DU, configurations for one or more candidate cells provided by the candidate DU, the one or more candidate cells including the first candidate cell; receiving a message from the DU indicating a L1 / L2 mobility procedure performed by the UE, wherein the message comprises: An indicator or identification of a first candidate cell for L1 / L2 based inter-cell mobility of a UE; an indication of a first transmission configuration indicator (TCI) state to be used by the UE to communicate with the first candidate cell; and Communicate with the UE in the first candidate cell based on the first TCI state.

[0276] C2. A method according to embodiment C1, wherein the indicator or identification of the first candidate cell and the indication of the first TCI state are received in a copy or encapsulation of a low-layer signaling message sent by the DU to the UE.

[0277] C3. A method according to any one of embodiments C1 to C2, wherein the indication of the first TCI state is an index of the first beam or reference signal (RS) sent in the candidate cell.

[0278] C4. The method according to embodiment C3 also includes: determining the first TCI state or its identifier based on the index of the first beam or RS and the mapping between the TCI state identifier used in the first candidate cell and the index of the beam or RS sent in the first candidate cell.

[0279] C5. The method according to any one of embodiments C1 to C2, wherein: The indication of the first TCI state is a TCI state identifier; and The method also includes: sending a mapping between a TCI state identifier used in the first candidate cell and an index of a beam or RS transmitted in the first candidate cell to the CU or DU.

[0280] C6. A method according to any one of embodiments C1 to C5, wherein the configuration for the first candidate cell includes an indication of whether the UE should perform a medium access control (MAC) reset when performing L1 / L2 inter-cell mobility for the first candidate cell.

[0281] C7. The method according to any one of embodiments C1 to C6, wherein communicating with a UE in a first candidate cell based on the first TCI state comprises one or more of the following: Sending a control channel of the first candidate cell in a beam or spatial direction corresponding to the first TCI; and In the beam or spatial direction corresponding to the first TCI state, uplink data or scheduling request is received from the UE in the first candidate cell.

[0282] C8. A method according to any one of embodiments C1 to C7, wherein the DU is associated with the CU and / or is part of a RAN node.

[0283] D1. A user equipment (UE) configured to communicate with a radio access network (RAN) node, the RAN node comprising a central unit (CU) and a distributed unit (DU) providing a serving cell for the UE, the UE comprising: a communication interface circuit configured to communicate with the CU and at least the DU; and The processing circuit is operably coupled to the communication interface circuit, wherein the processing circuit and the communication interface circuit are further configured to perform operations corresponding to the method of any one of embodiments A1 to A12.

[0284] D2. A user equipment (UE) configured to communicate with a radio access network (RAN) node, the RAN node comprising a central unit (CU) and a distributed unit (DU) providing a service cell for the UE, the UE being further configured to perform operations corresponding to the method of any one of embodiments A1 to A12.

[0285] D3. A non-temporary computer-readable medium storing computer-executable instructions which, when executed by a processing circuit of a user equipment (UE), configure the UE to perform operations corresponding to a method of any one of embodiments A1 to A12, wherein the UE is configured to communicate with a radio access network RAN ​​node, the RAN node comprising a central unit CU and a distributed unit DU providing a service cell for the UE.

[0286] D4. A computer program product comprising computer executable instructions which, when executed by a processing circuit of a user equipment (UE), configure the UE to perform operations corresponding to the method of any one of embodiments A1 to A12, wherein the UE is configured to communicate with a radio access network (RAN) node, the RAN node comprising a central unit (CU) and a distributed unit (DU) providing a service cell for the UE.

[0287] E1. A distributed unit (DU) of a radio access network (RAN) node, the DU coupled to a central unit (CU) of the RAN node and configured to provide a serving cell for a user equipment (UE), the DU comprising: A communication interface circuit configured to communicate with the CU and the UE; and The processing circuit is operably coupled to the communication interface circuit, so that the processing circuit and the communication interface circuit are configured to perform operations corresponding to the method of any one of embodiments B1 to B13.

[0288] E2. A distributed unit (DU) of a radio access network (RAN) node, the DU being coupled to a central unit (CU) of the RAN node and being configured to provide a service cell for a user equipment (UE), the DU being further configured to perform operations corresponding to the method of any one of embodiments B1 to B13.

[0289] E3. A non-transitory computer-readable medium storing computer-executable instructions which, when executed by a processing circuit of a distributed unit (DU), configure the DU to perform operations corresponding to the method of any one of embodiments B1 to B13, wherein the DU is coupled to a central unit (CU) of a radio access network (RAN) node and is configured to provide a service cell for a user equipment (UE).

[0290] E4. A computer program product comprising computer executable instructions which, when executed by a processing circuit of a distributed unit (DU), configure the DU to perform operations corresponding to the method of any one of embodiments B1 to B13, wherein the DU is coupled to a central unit (CU) of a radio access network (RAN) node and is configured to provide a service cell for a user equipment (UE).

[0291] F1. A candidate distributed unit (DU) of a radio access network (RAN) node, the candidate DU coupled to a central unit (CU) of the RAN node, the candidate DU comprising: a communication interface circuit configured to communicate with the CU and the UE via one or more cells provided by the candidate DU; and The processing circuit is operably coupled to the communication interface circuit, so that the processing circuit and the communication interface circuit are configured to perform operations corresponding to the method of any one of embodiments C1 to C8.

[0292] F2. A second distributed unit (DU) of a radio access network (RAN) node, the second DU being coupled to a centralized unit (CU) of the RAN node, the second DU being configured to perform operations corresponding to the method of any one of embodiments C1 to C8.

[0293] F3. A non-temporary computer-readable medium storing computer-executable instructions which, when executed by a processing circuit of a candidate distributed unit (DU) of a central unit (CU) coupled to a radio access network (RAN) node, configure the candidate DU to perform operations corresponding to the method of any one of embodiments C1 to C8.

[0294] F4. A computer program product comprising computer executable instructions which, when executed by a processing circuit of a candidate distributed unit (DU) of a central unit (CU) coupled to a radio access network (RAN) node, configure the candidate DU to perform operations corresponding to the method of any one of embodiments C1 to C8.

Claims

1. A method for a user equipment UE, the UE being configured to communicate with a radio access network RAN ​​node, the RAN node comprising a central unit CU and a distributed unit DU, the DU providing a serving cell for the UE, the method comprising: A low layer signaling message is received (1150) from the DU, the low layer signaling message indicating that the UE should perform L1 / L2 based inter-cell mobility on a first candidate cell provided by the candidate DU, wherein the low layer signaling message includes: an indicator or identification of the first candidate cell, and an indication of a first transmission configuration indicator (TCI) state to be used by the UE to communicate with the first candidate cell; An L1 / L2 mobility procedure is performed (1170) toward the first candidate cell, and communication is performed in the first candidate cell based on the first TCI state.

2. The method according to claim 1, wherein the indication of the first TCI state is one of the following: a TCI state identifier, or an index of a first beam or reference signal RS sent in the first candidate cell.

3. The method according to claim 2, further comprising: receiving (1110) an RRCReconfiguration message from the CU via the DU, the RRCReconfiguration message including a configuration associated with one or more candidate cells for L1 / L2 based inter-cell mobility, the one or more candidate cells including the first candidate cell, wherein: Each candidate cell configuration includes multiple TCI state configurations, and Each TCI state configuration includes an index of a beam or RS arranged as a quasi-co-located QCL source; and One of the TCI state configurations including the index of the first beam or RS as a QCL source is selected (1160) as the first TCI state.

4. The method of claim 3, further comprising sending (1120) an RRCReconfigurationComplete message to the CU via the DU in response to the RRCReconfiguration message.

5. The method according to any one of claims 3 to 4, wherein one of the following includes an indication of whether the UE should perform a medium access control (MAC) reset when performing the L1 / L2 inter-cell mobility for the first candidate cell: a configuration for the first candidate cell, or the low-layer signaling message.

6. The method of claim 5, wherein performing (1170) the L1 / L2 mobility procedure towards the first candidate cell comprises selectively performing (1171) one or more of the following operations based on the indication of whether the UE should perform a MAC reset: Initialize MAC state variables; Stop, start or restart the MAC timer; Resetting the new data indicator NDI for the uplink hybrid ARQ process to zero; Stop the ongoing MAC process; Cancel the MAC process that has been triggered but not carried out; Refresh MAC message buffer; Reset MAC counter; as well as The radio network temporary identifier RNTI allocated to the UE is released.

7. The method according to any one of claims 1 to 6, wherein the low layer signaling message further comprises an indication of whether the UE should perform a random access RA procedure when performing L1 / L2 inter-cell mobility on the first candidate cell.

8. The method of claim 7, wherein performing (1170) the L1 / L2 mobility procedure toward the first candidate cell comprises selectively performing (1172) a RA procedure in the first candidate cell based on one or more of: the indication of whether the UE should perform a RA procedure; whether the time alignment of the first candidate cell is different from the time alignment of the serving cell; whether the time alignment timer of the first candidate cell has expired; and Whether the time alignment of the first candidate cell is known or unknown.

9. The method according to any one of claims 1 to 8, wherein the method further comprises: Performing (1130) measurement on a plurality of beams or reference signals RS transmitted in the first candidate cell; as well as sending (1140) the measurement result to the DU, The first TCI state corresponds to the index of the beam or RS having the measurement result that is most beneficial to the L1 / L2 mobility of the first candidate cell.

10. The method according to claim 9, wherein the multiple beams or RSs include one or more of the following: synchronization signal / PBCH block SSB; and channel state information reference signal CSI-RS.

11. The method according to any one of claims 1 to 10, wherein one or more of the following apply: The low-layer signaling message is used for a protocol layer below the radio resource control RRC protocol layer; and The low-layer signaling message is one of the following: a medium access control MAC control element CE; or physical layer downlink control information DCI.

12. The method according to any one of claims 1 to 11, wherein communicating (1170) in the first candidate cell based on the first TCI state comprises one or more of: Monitoring (1173) a downlink control channel of the first candidate cell in a beam or spatial direction corresponding to the first TCI state; and Send (1174) uplink data or a scheduling request to the first candidate cell in a beam or spatial direction corresponding to the first TCI state.

13. The method according to any one of claims 1 to 12, wherein the candidate DU is associated with the CU and / or is part of the RAN node.

14. A method for a distributed unit DU of a radio access network RAN ​​node, the DU being configured to communicate with a central unit CU of the RAN node and to provide a serving cell for a user equipment UE, the method comprising: selecting (1250) a first candidate cell provided by the candidate DU for L1 / L2-based inter-cell mobility of a UE served by the DU via the serving cell; A low layer signaling message is sent (1280) to the UE indicating that the UE should perform L1 / L2 based inter-cell mobility for the first candidate cell, the low layer signaling message comprising: an indicator or identification of the first candidate cell, and An indication of a first transmission configuration indicator (TCI) state to be used by the UE to communicate with the first candidate cell.

15. The method according to claim 14, further comprising: A result of measurement performed by the UE on a plurality of beams or reference signals RS transmitted in the first candidate cell is received (1240) from the UE, wherein the measurement result includes corresponding indexes of the plurality of beams or RSs.

16. The method of claim 15, wherein the plurality of beams or RSs comprises one or more of: a synchronization signal / PBCH block SSB; and a channel state information reference signal CSI-RS.

17. The method according to any one of claims 15 to 16, wherein the first TCI state is associated with a first beam or RS having a measurement result that is most favorable for L1 / L2 mobility for the first candidate cell.

18. The method of claim 17, wherein the indication of the first TCI state is one of: the index of the first beam or RS, or a TCI state identifier.

19. The method according to claim 18, further comprising: The TCI state identifier for the first TCI state is determined (1260) based on: the index of the first beam or RS, which is the indication of the first TCI state; and A mapping between a TCI state identifier used in the first candidate cell and an index of a beam or RS sent in the first candidate cell.

20. The method according to claim 19, further comprising: The mapping is received (1205) from the candidate DU or the CU.

21. The method according to any one of claims 14 to 20, further comprising: Sending (1290) to the CU or the candidate DU a message including one or more of the following: the indicator or identity of the first candidate cell for L1 / L2 based inter-cell mobility of the UE; the indication of the first TCI state to be used by the UE to communicate with the first candidate cell; and A copy or encapsulation of the low-layer signaling message.

22. The method according to any one of claims 14 to 21, wherein the low-layer signaling message further comprises one or more of the following: an indication of whether the UE should perform a random access RA procedure when performing L1 / L2 inter-cell mobility for the first candidate cell; An indication of whether the UE should perform a medium access control (MAC) reset when performing L1 / L2 inter-cell mobility on the first candidate cell.

23. The method according to claim 22, further comprising: determining (1270) whether the UE should perform a RA procedure when performing L1 / L2 inter-cell mobility for the first candidate cell as indicated in the lower layer signaling message based on one or more of: whether the time alignment of the first candidate cell is different from the time alignment of the serving cell; whether the time alignment timer of the first candidate cell has expired; Whether the time alignment of the first candidate cell is known or unknown.

24. The method according to any one of claims 14 to 23, wherein one or more of the following apply: The low-layer signaling message is used for a protocol layer below the radio resource control RRC protocol layer; and The low-layer signaling message is one of the following: a medium access control MAC control element CE; or physical layer downlink control information DCI.

25. The method according to any one of claims 14 to 24, wherein the candidate DU is associated with the CU and / or is part of the RAN node.

26. The method according to any one of claims 14 to 25, further comprising: sending (1210) to the CU or the candidate DU a request to configure at least one candidate cell for L1 / L2 based inter-cell mobility to the UE; receiving (1220) from the CU or the candidate DU a configuration for one or more candidate cells provided by the candidate DU, the one or more candidate cells including the first candidate cell; and The configuration is sent (1230) to the UE in an RRCReconfiguration message.

27. A method for a candidate distributed unit DU of a radio access network RAN ​​node, the candidate DU being configured to communicate with a central unit CU of the RAN node, the method comprising: receiving (1320) a request to configure at least one candidate cell for L1 / L2 based inter-cell mobility to the UE from the CU or from a DU serving the UE via a serving cell; sending (1330) to the CU or the DU a configuration for one or more candidate cells provided by the candidate DU, the one or more candidate cells including a first candidate cell; receiving (1340) from the DU a message indicating a L1 / L2 mobility procedure performed by the UE, the message comprising: an indicator or identification of the first candidate cell for L1 / L2 based inter-cell mobility of the UE, and an indication of a first transmission configuration indicator (TCI) state to be used by the UE to communicate with the first candidate cell; as well as Communicate with the UE in the first candidate cell based on the first TCI state (1360).

28. The method of claim 27, wherein the indicator or identification of the first candidate cell and the indication of the first TCI state are received in a copy or encapsulation of a low layer signaling message sent by the DU to the UE.

29. A method according to any one of claims 27 to 28, wherein: The indication of the first TCI state is an index of a first beam or reference signal RS sent in the candidate cell; The method also includes determining (1350) the first TCI state or its identifier based on: an index of the first beam or RS, and a mapping between a TCI state identifier used in the first candidate cell and an index of a beam or RS sent in the first candidate cell.

30. The method according to any one of claims 27 to 28, wherein: The indication of the first TCI state is a TCI state identifier; and The method also includes sending (1310) to the CU or to the DU a mapping between a TCI state identifier used in the first candidate cell and an index of a beam or RS transmitted in the first candidate cell.

31. The method according to any one of claims 27 to 30, wherein the configuration for the first candidate cell comprises an indication of whether the UE should perform a Medium Access Control (MAC) reset when performing the L1 / L2 inter-cell mobility to the first candidate cell.

32. The method of any one of claims 27 to 31, wherein communicating (1360) with the UE in the first candidate cell based on the first TCI state comprises one or more of: Transmitting (1361) a control channel of the first candidate cell in a beam or spatial direction corresponding to the first TCI; and Uplink data or a scheduling request is received (1362) from the UE in the first candidate cell in a beam or spatial direction corresponding to the first TCI state.

33. The method according to any one of claims 27 to 32, wherein the DU is associated with the CU and / or is part of the RAN node.

34. A user equipment UE (510, 710, 1412, 1500, 1906) configured to communicate with a radio access network RAN ​​node (100, 550, 750, 1410, 1600, 1802, 1904), the RAN node comprising a central unit CU (110, 540, 740) and a distributed unit DU (120, 520, 720) providing a serving cell for the UE, the UE comprising: a communication interface circuit (1512) configured to communicate with the CU and at least the DU; as well as The processing circuit (1502) is operably coupled to the communication interface circuit, wherein the processing circuit and the communication interface circuit are configured to: A low layer signaling message is received from the DU, the low layer signaling message indicating that the UE should perform L1 / L2 based inter-cell mobility for a first candidate cell provided by the candidate DU, the low layer signaling message comprising: an indicator or identification of the first candidate cell, and an indication of a first transmission configuration indicator (TCI) state to be used by the UE to communicate with the first candidate cell; Performing an L1 / L2 mobility procedure toward the first candidate cell, and communicating in the first candidate cell based on the first TCI state.

35. The UE according to claim 34, wherein the processing circuit and the communication interface circuit are further configured to perform operations corresponding to the method according to any one of claims 2 to 13.

36. A user equipment UE (510, 710, 1412, 1500, 1906) configured to communicate with a radio access network RAN ​​node (100, 550, 750, 1410, 1600, 1802, 1904), the RAN node comprising a central unit CU (110, 540, 740) and a distributed unit DU (120, 520, 720) providing a serving cell for the UE, the UE being further configured to: receiving a low layer signaling message from the DU, the low layer signaling message indicating that the UE should perform L1 / L2 based inter-cell mobility on a first candidate cell provided by the candidate DU, wherein the low layer signaling message comprises: an indicator or identification of the first candidate cell, and an indication of a first transmission configuration indicator (TCI) state to be used by the UE to communicate with the first candidate cell; Performing an L1 / L2 mobility procedure toward the first candidate cell, and communicating in the first candidate cell based on the first TCI state.

37. The UE according to claim 36, further configured to perform operations corresponding to the method according to any one of claims 2 to 13.

38. A non-transitory computer-readable medium (1510) storing computer-executable instructions which, when executed by a processing circuit (1502) of a user equipment (UE) (510, 710, 1412, 1500, 1906), configure the UE to perform operations corresponding to the method according to any one of claims 1 to 13, wherein the UE (510, 710, 1412, 1500, 1906) is configured to communicate with a radio access network RAN ​​node (100, 550, 750, 1410, 1600, 1802, 1904), the RAN node (100, 550, 750, 1410, 1600, 1802, 1904) comprising a central unit CU (110, 540, 740) and a distributed unit DU (120, 520, 720) providing a serving cell for the UE.

39. A computer program product (1514) comprising computer executable instructions which, when executed by a processing circuit (1502) of a user equipment UE (510, 710, 1412, 1500, 1906), configure the UE to perform operations corresponding to the method according to any one of claims 1 to 13, wherein the UE (510, 710, 1412, 1500, 1906) is configured to communicate with a radio access network RAN ​​node (100, 550, 750, 1410, 1600, 1802, 1904), the RAN node (100, 550, 750, 1410, 1600, 1802, 1904) comprising a central unit CU (110, 540, 740) and a distributed unit DU (120, 520, 720) providing a serving cell for the UE.

40. A distributed unit DU (120, 520, 720) of a radio access network RAN ​​node (100, 550, 750, 1410, 1600, 1802, 1904), the DU being configured to communicate with a central unit CU (110, 540, 740) of the RAN node and to provide a serving cell for a user equipment UE (510, 710, 1412, 1500, 1906), the DU comprising: A communication interface circuit (1606, 1804), configured to communicate with the CU and the UE; as well as A processing circuit (1602, 1804) operably coupled to the communication interface circuit, whereby the processing circuit and the communication interface circuit are configured to: selecting a first candidate cell provided by a candidate DU (130, 530, 730) for L1 / L2 based inter-cell mobility of a UE served by the DU via the serving cell; Sending a low layer signaling message to the UE indicating that the UE should perform L1 / L2-based inter-cell mobility on the first candidate cell, the low layer signaling message comprising: an indicator or identification of the first candidate cell, and An indication of a first transmission configuration indicator (TCI) state to be used by the UE to communicate with the first candidate cell.

41. The DU of claim 40, wherein the processing circuit and the communication interface circuit are further configured to perform operations corresponding to the method of any one of claims 15 to 26.

42. A distributed unit DU (120, 520, 720) of a radio access network RAN ​​node (100, 550, 750, 1410, 1600, 1802, 1904), the DU being configured to communicate with a central unit CU (110, 540, 740) of the RAN node and to provide a serving cell for a user equipment UE (510, 710, 1412, 1500, 1906), the DU being further configured to: selecting a first candidate cell provided by a candidate DU (130, 530, 730) for L1 / L2 based inter-cell mobility of a UE served by the DU via the serving cell; Sending a low layer signaling message to the UE indicating that the UE should perform L1 / L2-based inter-cell mobility on the first candidate cell, the low layer signaling message comprising: an indicator or identification of the first candidate cell, and An indication of a first transmission configuration indicator (TCI) state to be used by the UE to communicate with the first candidate cell.

43. The DU of claim 42, further configured to perform operations corresponding to the method of any one of claims 15 to 26.

44. A non-transitory computer-readable medium (1604, 1804) storing computer-executable instructions which, when executed by a processing circuit (1402, 1604) of a distributed unit DU (120, 520, 720) of a radio access network RAN ​​node (100, 550, 750, 1410, 1600, 1802, 1904), configure the DU to perform operations corresponding to the method according to any one of claims 14 to 26.

45. A computer program product (1604a, 1804a) comprising computer executable instructions which, when executed by a processing circuit (1402, 1604) of a distributed unit DU (120, 520, 720) of a radio access network RAN ​​node (100, 550, 750, 1410, 1600, 1802, 1904), configure the DU to perform operations corresponding to the method according to any one of claims 14 to 26.

46. ​​A candidate distributed unit DU (130, 530, 730) of a radio access network RAN ​​node (100, 550, 750, 1410, 1600, 1802, 1904), the candidate DU being configured to communicate with a central unit CU (110, 540, 740) of the RAN node, the candidate DU comprising: A communication interface circuit (1606, 1804), configured to communicate with the CU and the user equipment UE (510, 710, 1412, 1500, 1906) via one or more cells provided by the candidate DU; as well as A processing circuit (1602, 1804) operably coupled to the communication interface circuit, whereby the processing circuit and the communication interface circuit are configured to: receiving, from the CU or from a DU (120, 520, 720) serving the UE via a serving cell, a request to configure at least one candidate cell for L1 / L2 based inter-cell mobility to the UE; Sending, to the CU or the DU, configurations for one or more candidate cells provided by the candidate DU, the one or more candidate cells including a first candidate cell; receiving, from the DU, a message indicating a L1 / L2 mobility procedure performed by the UE, the message comprising: an indicator or identification of the first candidate cell for L1 / L2 based inter-cell mobility of the UE, and an indication of a first transmission configuration indicator (TCI) state to be used by the UE to communicate with the first candidate cell; as well as and communicating with the UE in the first candidate cell based on the first TCI state.

47. The candidate DU of claim 46, wherein the processing circuit and the communication interface circuit are further configured to perform operations corresponding to the method of any one of claims 28 to 33.

48. A candidate distributed unit DU (130, 530, 730) of a radio access network RAN ​​node (100, 550, 750, 1410, 1600, 1802, 1904), the candidate DU being configured to communicate with a central unit CU (110, 540, 740) of the RAN node, the candidate DU being further configured to: receiving, from the CU or from a DU (120, 520, 720) serving a user equipment UE (510, 710, 1412, 1500, 1906) via a serving cell, a request to configure at least one candidate cell for L1 / L2 based inter-cell mobility to the UE; Sending, to the CU or the DU, configurations for one or more candidate cells provided by the candidate DU, the one or more candidate cells including a first candidate cell; receiving, from the DU, a message indicating a L1 / L2 mobility procedure performed by the UE, the message comprising: an indicator or identification of the first candidate cell for L1 / L2 based inter-cell mobility of the UE, and an indication of a first transmission configuration indicator (TCI) state to be used by the UE to communicate with the first candidate cell; as well as and communicating with the UE in the first candidate cell based on the first TCI state.

49. The candidate DU according to claim 48, further configured to perform operations corresponding to the method according to any one of claims 28 to 33.

50. A non-transitory computer-readable medium (1604, 1804) storing computer-executable instructions which, when executed by a processing circuit (1602, 1804) of a candidate distributed unit DU (130, 530, 730) of a radio access network RAN ​​node (100, 550, 750, 1410, 1600, 1802, 1904), configure the candidate DU to perform operations corresponding to the method according to any one of claims 27 to 33.

51. A computer program product (1604a, 1804a), comprising computer executable instructions, which, when executed by a processing circuit (1602, 1804) of a candidate distributed unit DU (130, 530, 730) of a radio access network RAN ​​node (100, 550, 750, 1410, 1600, 1802, 1904), configures the candidate DU to perform operations corresponding to the method according to any one of claims 27 to 33.

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