L1 / L2 inter-cell mobility execution with candidate du participation

Abstract

Embodiments include a method for a user equipment (UE) configured to communicate with a radio access network (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 the DUs, one or more low-layer signaling messages indicating that the UE should perform L1 / L2-based inter-cell mobility to 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 timing offset or adjustment to be used by the UE. Such a method includes performing an L1 / L2 mobility procedure towards the first candidate cell and communicating in the first candidate cell based on the timing offset or adjustment. Other embodiments include supplemental methods for the CU, the DU, and the candidate DU, as well as the UE, CU, and DU 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) across multiple cells in a wireless network, in particular cells provided by different distributed units (DUs) that may be associated with a single central unit (CU). Background Art

[0002] Currently, fifth generation (5G) cellular systems are being standardized within the 3rd Generation Partnership Project (3GPP). 5G is being developed to provide maximum flexibility to support a wide range of distinct use cases. These use cases 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 including 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 gNBs 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 used with a 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 corresponding cells. In general, a DL "beam" is a coverage area of ​​a network-transmitted 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 transmission and signaling transmission.

[0007] Figure 1 The NG RAN logical nodes shown in the figure 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-level protocols and performs various gNB functions (such as controlling the operation of the DU). The DU is a decentralized logical node that hosts low-level protocols and may include various subsets of gNB functions depending on the functional partitioning options. Therefore, each of the CU and DU may include various circuits required to perform their respective functions, including processing circuits, communication interface circuits (such as transceivers), and power supply circuits.

[0008] gNB-CU through the corresponding F1 logical interface (e.g. Figure 1 122 and 132) shown in Figure 1 are connected to one or more gNB-DUs. However, a gNB-DU may be connected to only a single gNB-CU. The gNB-CU and its connected gNB-DUs are visible only as gNBs to other gNBs and the 5GC. 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), medium access control (MAC), radio link control (RLC) and packet data convergence protocol (PDCP) layers 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 both 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) for delivery 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 of QoS Flow Identifiers (QFIs) in UL and DL packets. The RLC transmits the PDCP PDUs to the MAC over a logical channel (LCH). The RLC provides error detection / correction, concatenation, segmentation / reassembly, sequence numbering, and reordering of data transmitted to / from upper layers. The MAC provides mapping between LCH and PHY transport channels, LCH prioritization, multiplexing into 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) used by the UE. Additionally, 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, the UE 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 transmission can take place). 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 learned 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 continues to NR. To maintain compatibility with legacy UEs from earlier releases (such as Rel-8), wideband LTE Rel-10 carriers are displayed 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 viewed as "cells" so that a UE in CA has one primary cell (PCell) and one or more secondary cells (SCells). These cells are collectively referred to as a "cell group". Starting from Rel-15, NR also supports CA.

[0014] As specified in 3GPP document RP-213565, NRRel-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 performed at some point in time. Currently, serving cell changes are triggered by Layer 3 (L3, such as RRC) measurements and involve RRC signaling to change PCell and PSCell (for example, when dual connectivity is configured), as well as release / add SCell (for example, 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, more signaling overhead, and longer outages than intra-cell beam switching. Therefore, the goal of Rel-18 L1 / L2 mobility enhancements is to facilitate serving cell changes via 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 intra-DU and inter-DU / intra-CU cell changes, wherein the source cell and target cell of a UE are served by different source DUs and target DUs associated with a single CU. However, there are various challenges, problems and / or difficulties.

[0017] For example, because 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 after) 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. However, currently the UE does not have the necessary information about the target cell configuration to initiate communication in a way that effectively reduces the interruption time.

[0018] It is an object of embodiments of the present disclosure to address these and related challenges, problems 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, processes) for a UE configured to communicate with a RAN node including a CU and a DU providing a serving cell for the UE.

[0020] These exemplary methods include: receiving one or more low layer signaling messages from the DU, the one or more low layer signaling messages indicating that the UE should perform L1 / L2 based inter-cell mobility to a first candidate cell provided by the candidate DU. The one or more low layer signaling messages include: an indicator or identification of the first candidate cell, and an indication of a timing offset or adjustment to be used by the UE in the first candidate cell. In some embodiments, the candidate DU is associated with the CU and / or is part of the RAN node. These exemplary methods also include: performing an L1 / L2 mobility procedure towards the first candidate cell, and communicating in the first candidate cell based on the timing offset or adjustment.

[0021] In some embodiments, the one or more low layer signaling messages further include an indication of a first transmission configuration indicator (TCI) state to be used by the UE for communicating with the first candidate cell. In such an embodiment, communicating in the first candidate cell is further based on the first TCI state.

[0022] 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 transmitted in the first candidate cell.

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

[0024] The exemplary methods include selecting a first candidate cell provided by a candidate DU for L1 / L2-based inter-cell mobility of a UE served by the DU via the serving cell. The exemplary methods also include sending a request for L1 / L2-based inter-cell mobility of the UE to the CU. The request includes an indicator or identification of the first candidate cell and a request for a timing offset or adjustment to be used by the UE for communication with the first candidate cell. The exemplary methods also include receiving a response from the CU including the following information:

[0025] a message compatible with low layer signaling between the UE and the DU, wherein the message includes the indicator or identity of the first candidate cell; and

[0026] • An indication of a timing offset or adjustment to be used by the UE in the first candidate cell.

[0027] These exemplary methods also include sending one or more low layer signaling messages to the UE, the one or more low layer signaling messages indicating that the UE should perform L1 / L2 based inter-cell mobility to the first candidate cell. The one or more low layer signaling messages include the information received in the response (e.g., from the CU).

[0028] In some embodiments, the request further comprises a first indication of a first TCI state proposed for use by the UE to communicate with the first candidate cell, and the message compatible with low layer signaling comprises a second indication of the first TCI state.

[0029] In some of these embodiments, the first indication of the first TCI state is the index of the first beam or RS. In other of these embodiments, the first indication of the first TCI state is a TCI state identifier. In some embodiments, the second indication of the first TCI state (e.g., in the message compatible with low layer signaling) is a TCI state identifier.

[0030] Other embodiments include methods (eg, processes) for a candidate DU of a RAN node, the candidate DU being configured to communicate with a CU of the RAN node.

[0031] These exemplary methods may include receiving, from the CU, a request for L1 / L2 based inter-cell mobility for a UE served by the DU via a serving cell. The request includes an indicator or identification of the first candidate cell and a request for a timing offset or adjustment for the UE to communicate with the first candidate cell. In some embodiments, the DU is associated with the CU and / or is part of the RAN node. These exemplary methods may also include sending to the CU a response including the following information:

[0032] a message compatible with low layer signaling between the UE and the DU, wherein the message includes the indicator or identity of the first candidate cell; and

[0033] • An indication of a timing offset or adjustment to be used by the UE in the first candidate cell.

[0034] The example methods further include communicating with the UE in the first candidate cell based on the indicated timing offset or adjustment.

[0035] In some embodiments, the request also includes a first indication of a first TCI state recommended for use by the UE to communicate with the first candidate cell, the message compatible with low layer signaling includes a second indication of the first TCI state, and communicating with the UE in the first candidate cell is further based on the first TCI state.

[0036] In some of these embodiments, the first indication of the first TCI state is an index of a first beam or reference signal RS transmitted in the first candidate cell. In other of these embodiments, the first indication of the first TCI state is a TCI state identifier. In some of these embodiments, the second indication of the first TCI state (e.g., in the message compatible with low layer signaling) is a TCI state identifier.

[0037] Other embodiments include methods (eg, processes) for a CU of a RAN node, the CU being configured to communicate with a plurality of DUs of the RAN node.

[0038] These exemplary methods include receiving, from a DU serving a UE in a serving cell, a request for L1 / L2 based inter-cell mobility for the UE. The request includes:

[0039] An indicator or identity of a first candidate cell for L1 / L2 based inter-cell mobility of the UE, wherein the first candidate cell is served by the candidate DU; and

[0040] • A request for a timing offset or adjustment to be used by the UE for communicating with the first candidate cell.

[0041] The example methods further include forwarding the request to the candidate DU, and receiving a response from the candidate DU including:

[0042] a message compatible with low layer signaling between the UE and the DU, wherein the message includes the indicator or identity of the first candidate cell; and

[0043] • An indication of a timing offset or adjustment to be used by the UE in the first candidate cell.

[0044] The example methods may also include forwarding the response to the DU.

[0045] In some embodiments, the request further comprises a first indication of a first TCI state suggested for use by the UE to communicate with the first candidate cell, and the message compatible with low layer signaling comprises a second indication of the first TCI state.

[0046] In some of these embodiments, the first indication of the first TCI state is a TCI state identifier or an index of a first beam or RS transmitted in the first candidate cell. In some of these embodiments, the second indication of the first TC1 state is a TCI state identifier.

[0047] In some embodiments, the request further comprises results of measurements performed by the UE on a plurality of beams or reference signals RS transmitted in the first candidate cell.

[0048] Other embodiments include UEs, DUs, and CUs 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, DUs, and CUs to perform operations corresponding to any of the exemplary methods described herein.

[0049] These and other embodiments described herein can facilitate the execution of L1 / L2 inter-cell mobility more reliably because the execution phase is completed in coordination with the candidate DU and / or CU. Therefore, when the UE receives low-layer signaling indicating the execution of L1 / L2 inter-cell mobility, the signaling comes directly from the candidate DU of the candidate cell that the serving UE will enter. These advantages can be facilitated by providing the UE with a TA indication (e.g., a command) and TCI state information (e.g., a TCI state ID or SSB index) for the candidate cell in low-layer signaling that triggers the execution of L1 / L2 inter-cell mobility and 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 can avoid data loss and excessive interruptions when a MAC reset is unnecessary. At a high level, the embodiments improve mobility in a RAN (e.g., an NG-RAN).

[0050] These and other objects, features and advantages of the present disclosure will become apparent when the following detailed description is read in view of the accompanying drawings which are briefly described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A high-level view of an exemplary 5G network architecture is shown;

[0052] Figure 2 An exemplary configuration of the NR UP and CP protocol stacks is shown;

[0053] Figure 3-4 shows the Figure 1 Logical architecture of a gNB arranged in a split CU / DU architecture as shown;

[0054] Figure 5 The signaling flow for the inter-DU / intra-CU mobility procedure of the UE is shown;

[0055] Figure 6 (which includes Figures 6A-6F ) shows various ASN.1 data structures for configuring L1 / L2 inter-cell mobility candidates for a UE according to various embodiments of the present disclosure;

[0056] Figure 7 A signaling flow for configuring a UE for inter-DU L1 / L2 inter-cell mobility from a serving DU to a candidate DU (both DUs are associated with the same CU) according to various embodiments of the present disclosure is shown;

[0057] Figure 8 An exemplary method (e.g., process) for a UE according to various embodiments of the present disclosure is shown;

[0058] Fig. 9An exemplary method (e.g., process) for serving a DU according to various embodiments of the present disclosure is shown;

[0059] Fig.10 An exemplary method (e.g., process) for candidate DUs according to various embodiments of the present disclosure is shown;

[0060] Fig.11 An exemplary method (e.g., process) for a CU according to various embodiments of the present disclosure is shown;

[0061] Fig.12 A communication system according to various embodiments of the present disclosure is shown;

[0062] Fig.13 A UE according to various embodiments of the present disclosure is shown;

[0063] Fig.14 shows a network node according to various embodiments of the present disclosure;

[0064] Fig.15 A host computing system according to various embodiments of the present disclosure is shown;

[0065] Fig.16 is a block diagram of a virtualization environment in which the functions implemented by some embodiments of the present disclosure may be virtualized;

[0066] Fig.17 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

[0067] 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 these descriptions should not be construed as limiting the scope of the subject matter to only the embodiments described herein. More specifically, the examples provided below illustrate the operation of various embodiments according to the advantages discussed above.

[0068] In general, all terms used herein should be interpreted according to their common meaning to those of ordinary skill in the relevant technical field, unless different meanings are explicitly defined and / or different meanings are implied from the context of use. Unless explicitly stated or clearly implied from the context of use, all references to one / an / the element, device, assembly, part, step, etc. should be publicly interpreted as referring to at least one instance of the element, device, assembly, part, step, etc. The operation of any method and / or process disclosed herein does not have to be performed in the exact order disclosed, unless an operation is explicitly described as after or before another operation and / or it is implied that an operation must be after or before another operation. Where appropriate, any feature of any embodiment disclosed herein may be applied to any other disclosed embodiment. Similarly, where appropriate, any advantage of any embodiment described herein may be applicable to any other disclosed embodiment.

[0069] Furthermore, the following terms are used throughout the description given below:

[0070] 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 a radio access network (RAN) node.

[0071] Any node in a radio access node for wirelessly transmitting and / or receiving 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 base stations, pico base stations, femto base stations, 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.

[0072] Core network node: As used herein, a "core network node" is any type of node in a core network. Some examples of core network nodes include, for example, a mobility management entity (MME), a serving gateway (SGW), a PDN gateway (P-GW), a policy and charging rules function (PCRF), an access and mobility management function (AMF), a session management function (SMF), a user plane function (UPF), a charging function (CHF), a policy control function (PCF), an authentication server function (AUSF), a location management function (LMF), etc.

[0073] Wireless device: As used herein, a "wireless device" (or "WD" for short) is any type of device capable of, configured to, arranged to, and / or operable to wirelessly communicate 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 over the air. Unless otherwise specified, the term "wireless device" may be used interchangeably herein with the term "user equipment" (or "UE" for short), which terms have different meanings from the term "network node".

[0074] • Radio node: As used herein, a "radio node" may be a "radio access node" (or equivalent terms) or a "wireless device".

[0075] 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 of a cellular communication network (e.g., a core network node discussed above). Functionally, a network node is a device that is capable of, configured to, arranged to, and

[0076] and / or operable to communicate directly or indirectly with the wireless device and / or with other network nodes or devices in the cellular communication network to enable and / or provide wireless access to the wireless device, and / or to perform other functions (e.g., management) in the cellular communication network.

[0077] Node: As used herein, the term "node" (without a prefix) may be any type of node capable of being 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, based on the specific characteristics of the term "node" in any given context, it may be limited to a specific type (e.g., a radio access node, an IAB node).

[0078] The above definitions are not meant to be exclusive. In other words, the same or similar terms may be used to explain and / or describe the various terms in the above terms in other locations of the present disclosure. However, if such other explanations and / or descriptions conflict with the above definitions, the above definitions shall prevail.

[0079] 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 (particularly for 5G NR) that beams can be used instead of cells, and therefore, the concepts described herein are equally applicable to both cells and beams.

[0080] Figure 3 A gNB (e.g. Figure 1 The logical architecture of the gNB 100 in Figure 1 is shown in Figure 1. This 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.

[0081] Figure 4 Another exemplary gNB logical architecture is shown, which includes two gNB-DUs, one gNB-CU-CP, and multiple gNB-CU-UPs. The gNB-CU-CP may be connected to the gNB-DU via an F1-C interface, and the gNB-CU-UP may be connected to the gNB-DU via an F1-U interface and to the gNB-CU-CP via an E1 interface. Each gNB-DU may be connected to only one gNB-CU-CP, and each gNB-CU-UP may be connected to only one gNB-CU-CP. One gNB-DU may be connected to multiple gNB-CU-UPs under the control of the same gNB-CU-CP. In addition, one gNB-CU-UP may be connected to multiple DUs under the control of the same gNB-CU-CP. When reference is made herein to an operation performed by a "CU", it should be understood that, unless otherwise specified, the operation may be performed by any entity within the CU (e.g., CU-CP, gNB-CU-CP).

[0082] 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 RRC signaling to change PCell and PSCell (e.g., when dual connectivity is configured), as well as releasing / adding SCells (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 and target cells are served by different source and target DUs associated with a single CU.

[0083] Figure 5 The signaling flow of 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 for ease of explanation and is not intended to require or imply any particular order of operations unless explicitly stated otherwise.

[0084] In operation 1, the UE sends a MeasurementReport message to the source DU. In operation 2, the source DU sends a UL RRC MESSAGE TRANSFER message to the CU to transmit 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.

[0085] In operation 3, the CU sends a UE CONTEXT SETUP REQUEST message to the target DU to create a UE context and establish one or more data bearers. The UE CONTEXT SETUP REQUEST message includes HandoverPreparationInformation. In operation 4, the target DU responds to the CU with a UE CONTEXT SETUP RESPONSE message.

[0086] In operation 5, the CU sends a UE CONTEXT MODIFICATION REQUEST message to the source DU, which includes the generated RRCReconfiguration message and indicates to stop data transmission for the UE. The source DU also sends a downlink data transfer status frame to notify the CU that the downlink data transmission to the UE is unsuccessful. 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.

[0087] In operation 8, the UE performs a random access procedure performed at the target DU. The target DU sends a downlink data transfer status frame to notify the CU. Downlink packets (which 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 transfer status depends on the CU implementation.

[0088] In operation 9, the UE responds to the target DU with an RRCReconfigurationComplete message. In operation 10, the target DU sends an UL RRC MESSAGE TRANSFER message to the CU to transmit the received RRCReconfigurationComplete message. Downlink packets are sent to the UE. In addition, uplink packets are sent from the UE and they are forwarded to the CU via the target DU. In operation 11, the CU sends a UECONTEXT RELEASE COMMAND message to the source DU. In operation 12, the source DU releases the UE context.

[0089] As briefly mentioned above, NR Rel-18 includes a work item on NR mobility enhancements, which includes 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 rather than L3 (e.g., RRC) signaling. One area of ​​interest is inter-DU / intra-CU cell changes, such as the above Figure 5 From the UE's perspective, Figure 5 The process shown in may involve longer delays, more signaling overhead, and longer interruptions than intra-cell beam switching.

[0090] 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:

[0091] Configuration and maintenance of multiple candidate cells to allow rapid application of configurations for candidate cells;

[0092] Dynamic switching mechanism between candidate serving cells (including SpCell and SCell) for potential applicable scenarios based on L1 / L2 signaling;

[0093] L1 enhancements for inter-cell beam management (including L1 measurements and reporting) and beam indication;

[0094] Timed advance management; and

[0095] CU-DU interface signaling to support L1 / L2 mobility (if required).

[0096] These Rel-18 L1 / L2 mobility enhancements must also take into account Figure 1 and 3 -The split CU / DU architecture shown in 4, including 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 the neighbor DUs of the (serving or source) DU that currently provides the UE's PCell (or PSCell, for SCG changes in DC).

[0097] like Figure 5 As shown in , 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 target cell configuration (e.g., CellGroupConfig) to the CU. Therefore, when the target DU receives the UE CONTEXT SETUP REQUEST (operation 3), the target DU knows that the UE will arrive at the target cell shortly after the UE receives the RRCReconfiguration from the CU via the source DU, so that any target cell resources reserved for the incoming UE will be used soon.

[0098] Because 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) it receives 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 cell it is moving to so that the UE can apply the corresponding configuration, including the correct timing alignment and / or transmission configuration indicator (TCI) status of 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 and be ready to receive scheduling requests (SRs) from the UE.

[0099] Each TCI state includes parameters for configuring a quasi-co-location (QCL) relationship between one or more source DL reference signals (RS, such as 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 CSI-RS port of a DL channel state information RS (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 condition: the properties of the channel on which symbols on one antenna port are transmitted can be inferred from the channel on which symbols on another antenna port are transmitted.

[0100] However, currently the UE does not have the necessary information about the target cell configuration (eg, TCI state) to initiate communications in a manner that effectively reduces the interruption time.

[0101] Embodiments of the present disclosure address these and other challenges, difficulties and / or problems 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 candidate cell configured for the UE. The low layer signaling includes information about a candidate cell served by such a candidate DU: the candidate DU and the source DU are associated with the same CU.

[0102] In some embodiments, the information about the candidate cell may include 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 (for example, 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 of the target cell, determine the corresponding TCI state ID, and provide this information to the UE in low-layer signaling.

[0103] In other embodiments, the information about the candidate cell may include an SSB index that identifies the source RS (i.e., SSB) of the QCL source for the TCI state. Based on the target cell configuration and the SSB index, the UE selects the TCI state of the target cell to be used during L1 / L2 inter-cell mobility execution. In particular, the UE selects a TCI state configuration in which the indicated SSB index is configured as the QCL source.

[0104] In some embodiments, the information about the candidate cells may include an indication of a timing advance (TA) that the UE should apply in the candidate cells when performing the L1 / L2 inter-cell mobility procedure.

[0105] 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.

[0106] Embodiments may provide various benefits and / or advantages. For example, embodiments may facilitate the execution of L1 / L2 inter-cell mobility more reliably because the execution phase is completed in coordination with the candidate DU and / or CU. Therefore, when the UE receives low-layer signaling indicating the execution of L1 / L2 inter-cell mobility, the low-layer signaling comes directly from the candidate DU serving the candidate cell that the UE will enter. These advantages are achieved by providing the UE with a TA indication (e.g., a TA command) and TCI state information (e.g., a TCI state ID or SSB index) for the candidate cell in the low-layer signaling, which triggers the execution of 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 process, the embodiments avoid data loss and excessive interruptions when a MAC reset is not necessary. At a high level, the embodiments improve mobility in a RAN (e.g., an NG-RAN).

[0107] 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 the network instructing 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 improve mobility robustness because the network is able to respond more quickly to changes in the UE's channel conditions.

[0108] In the present disclosure, the following terms may be used interchangeably for L1 / L2 inter-cell mobility: "neighbor DU", "non-serving DU", "candidate DU" and "target DU". Similarly, the terms "serving DU" and "source DU" may be used interchangeably for L1 / L2 inter-cell mobility.

[0109] Another relevant aspect of L1 / L2 inter-cell mobility is that a cell can be associated with multiple SSBs (or beams), with different SSBs being transmitted in different spatial directions during a half-frame, thereby spanning the coverage area of ​​the cell. A cell can also be associated with multiple CSI-RS resources, which can be transmitted in different spatial directions. Therefore, 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.

[0110] 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 an RRCReconfiguration message received by the UE when configured with inter-DU L1 / L2 inter-cell mobility. 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 required for the UE to operate in the candidate cell upon receiving low-layer signaling indicating L1 / L2-based inter-cell mobility to the corresponding candidate cell, which becomes the target cell for mobility at this time.

[0111] The configuration of L1 / L2 based inter-cell mobility candidate cells may include parameters of a serving cell (or multiple 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:

[0112] Cell index (e.g. encoding 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, this index can then be used in low layer signaling to indicate to the UE that this is the candidate cell that the UE needs to move to in the L1 / L2 inter-cell mobility procedure, and / or in RRC messages indicating some kind of operation in this particular candidate cell.

[0113] UE (e.g., UE-specific or UE-dedicated) cell configuration, which corresponds 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 (which is defined in 3GPP TS 38.331), such as DL and UL frequency configuration (including bandwidth parts), L1 control channels (e.g., PDCCH, CORESET, PUCCH), L1 data channels (e.g., PDSCH, PUSCH), etc.

[0114] Common cell configuration, which corresponds to the configuration of L1 / L2 based inter-cell mobility candidate cells in the ServingCellConfigCommon IE. This can be provided in the ReconfigurationWithSync IE or provided separately. The common cell configuration contains, for example, RA configuration for the UE to access the candidate cell when necessary.

[0115] • Radio link failure configuration, such as the value of timer T310, counter N310, counter N311, timer T311.

[0116] • At least one UE identifier that identifies the UE in an L1 / L2 based inter-cell mobility candidate cell, such as a Cell Radio Network Temporary Identifier (C-RNTI).

[0117] 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.

[0118] 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 of an 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 of 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 for the UE to receive one configuration per 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.

[0119] 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.

[0120] In some embodiments, the L1 / L2 inter-cell mobility candidate may be at the same frequency as the current PCell, or at a different frequency. In some embodiments, the L1 / L2 inter-cell mobility candidate may be a SCell candidate.

[0121] The RRC signaling implementation for configuring L1 / L2 based inter-cell mobility candidate cells may be accomplished in different ways corresponding to various embodiments. Some examples are described below.

[0122] Some embodiments may utilize one RRCReconfiguration message per candidate cell. In this case, the UE receives multiple (a series of) RRCReconfiguration messages within a single RRCReconfiguration message, such as Fig. 6AAs shown in . 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 receipt of low layer signaling for the corresponding L1 / L2 inter-cell mobility procedure to the candidate cell. As in L3 reconfiguration, this model enables the target node to modify / release / maintain any parameters / fields (e.g., measurement configuration, bearer, etc.) in the existing RRCReconfiguration message with full flexibility.

[0123] As an example of these embodiments, the neighbor DU generates a CellGroupConfig IE for each candidate (including candidate SpCell and SCell, if applicable), and the CU generates an RRCReconfiguration message for each candidate based on the corresponding CellGroupConfig IE. These IEs and messages are received and stored by the UE to be applied when the UE subsequently receives an L1 / L2 inter-cell mobility command (e.g., MAC CE) indicating a specific cell in the candidate cells.

[0124] Other embodiments may utilize one CellGroupConfig IE per candidate cell.Using this model, the UE receives a list of CellGroupConfig IEs within the RRCReconfiguration message, each IE identifying and / or including the configuration of a candidate cell for L1 / L2 based inter-cell mobility. 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 for the corresponding L1 / L2 inter-cell mobility procedure to that candidate cell. This model allows a neighbor DU to modify / release / retain any parameter / field that is part of the CellGroupConfig IE, while the rest of the RRCReconfiguration message (in which the UE receives the CellGroupConfig IE) remains unchanged. This means that measurement configuration, bearers, security, etc. remain unchanged and are not changed by the target node.

[0125] As an example of these embodiments, the neighbor DU generates a CellGroupConfig IE for each target candidate (including associated candidate SpCells and SCells), and the CU generates an RRCReconfiguration message with a list of CellGroupConfig IEs. These IEs and messages are received and stored by the UE to be applied when the UE subsequently receives an L1 / L2 inter-cell mobility command (e.g., MAC CE) indicating a specific cell in the candidate cells.

[0126] 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. This solution provides only minimal flexibility for neighbor DUs, because when generating K SpCellConfig IEs and / or K ServingCellConfigCommon IEs to be provided to the UE, the neighbor DU can only modify / release / retain cell-specific parameters (e.g., bandwidth part, DL / UL configuration). Figure 6C-6E Examples of these embodiments are shown.

[0127] Other embodiments may provide multiple (K) physical cell identifiers (PCIs) to the UE in the same PCell. Fig. 6F Examples of these embodiments are shown. Using this model, multiple PCIs are configured for the same TCI state configuration, where each PCI identifies the configuration of L1 / L2 based inter-cell mobility candidate cells. This approach does not provide flexibility at all, because all parameters / fields for configuring L1 / L2 based inter-cell mobility candidate cells are fixed, and only changes to PCI, scrambling of ID and / or C-RNTI are allowed for neighbor DUs.

[0128] 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 by high-layer (e.g., RRC) signaling. The candidate cell configuration may be (or be 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 cell different from the serving cell of the UE.

[0129] In some embodiments, the serving (or source) DU determines the triggering of L1 / L2 inter-cell mobility of the UE to one of the candidate cells previously configured for L1 / L2 inter-cell mobility of the UE. 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.

[0130] 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.

[0131] In some embodiments, the SS-RSRP may be derived as a linear average over 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) of the L1 / L2 inter-cell candidate cells and (if indicated by higher layers) the CSI-RS of the L1 / L2 inter-cell candidate cells.

[0132] In one embodiment, the SS-RSRP indicates a specific SSB for performing SS-RSRP measurement, 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.

[0133] In some embodiments, the measurement information for the L1 / L2 inter-cell mobility candidate cell may include one of the following:

[0134] SS reference signal received quality (SS-RSRQ) measurement for at least one configured / indicated SSB of an L1 / L2 inter-cell mobility candidate cell;

[0135] SS signal to interference and noise ratio (SS-

[0136] SINR) measurement.

[0137] A CSI-RS received power (CSI-RSRP) measurement for at least one configured / indicated CSI-RS resource of 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 the RSRP measurement within the considered measurement frequency bandwidth in the configured CSI-RS opportunities.

[0138] • CSI-RS Received Quality (CSI-RSRQ) measurement of at least one configured / indicated CSI-RS resource for L1 / L2 inter-cell mobility candidate cells.

[0139] • CSI-RS Signal to Interference and Noise Ratio (CSI-SINR) measurement for at least one configured / indicated CSI-RS resource of the L1 / L2 inter-cell mobility candidate cell.

[0140] Based on the L1 / L2 inter-cell mobility candidate cell's L1 reference signal received power (L1-

[0141] RSRP).

[0142] • L1 reference signal received power (L1-RSRP) based on at least one CSI-RS resource of the L1 / L2 inter-cell mobility candidate cell.

[0143] • Layer 1 SINR (L1-SINR) based on at least one SSB of the L1 / L2 inter-cell mobility candidate cell.

[0144] • Layer 1 SINR (L1-SINR) based on at least one CSI-RS resource of the L1 / L2 inter-cell mobility candidate cell.

[0145] • Channel Quality Indicator (CQI) based on SSB and / or CSI-RS in the CSI resource configuration.

[0146] • Precoding matrix indicator (PMI) based on SSB and / or CSI-RS in the CSI resource configuration.

[0147] • CSI-RS Resource Indicator (CRI) based on the SSB and / or CSI-RS in the CSI resource configuration.

[0148] · SS / PBCH Block Resource Indicator (SSBRI) based on SSB and / or CSI-RS in the CSI resource configuration.

[0149] • Layer Indicator (LI) based on SSB and / or CSI-RS in the CSI resource configuration.

[0150] • Rank Indicator (RI) based on SSB and / or CSI-RS in the CSI resource configuration.

[0151] In some embodiments, after determining the need for L1 / L2 mobility of the UE, the source DU sends a request for L1 / L2 mobility execution to the candidate DU (directly or via the CU), the request including one or more of the following:

[0152] An indicator or identification of a candidate cell (served by the candidate DU) selected by the serving DU for UE L1 / L2 inter-cell mobility;

[0153] An indication of the TCI state selected or determined by the serving DU for the UE to use for communicating with the candidate cell;

[0154] • CSI (or other measurement) reports received from the UE (or relevant parts thereof) which have triggered the need for UE L1 / L2 inter-cell mobility towards a candidate cell.

[0155] • A request for a timing offset or adjustment for the UE to use to communicate with the candidate cell.

[0156] In some embodiments, the indicated candidate cell may be one of the configured candidate cells for which the UE provides measurement reports to the source DU, e.g., the candidate cell for which the UE indicates the highest RSRP, RSRQ and / or SINR.

[0157] After receiving the request from the serving DU, the recipient (i.e., the candidate DU or CU) generates a message compatible with the low-layer signaling between the UE and the serving DU for the UE, and sends the message to the serving DU in a response or confirmation to the request. The message compatible with the low-layer signaling includes one or more of the following items:

[0158] An indicator or identification of a candidate cell, which instructs the UE to perform L1 / L2 mobility to the candidate cell;

[0159] An indication of the TCI state, which the UE should use to communicate with the candidate cell; and

[0160] • An indication of a timing offset or adjustment (eg a TA command) which the UE will use to adjust its DL-UL timing offset before performing its initial UL transmission in the candidate cell.

[0161] In some embodiments, one or more of the items listed above may be included in a message compatible with low layer signaling, and one or more other items listed above may be sent to the serving DU along with the message compatible with low layer signaling.

[0162] For example, after receiving a request from a serving DU, the CU may forward the request to a candidate DU of the serving candidate cell. If the candidate DU accepts the parameters in the request, the candidate DU creates a message compatible with the low-layer signaling between the UE and the serving DU for the UE and forwards the message to the CU. The CU then forwards the message to the serving DU. All communications between the CU and the serving / candidate DU may be based on appropriate F1 interface signaling.

[0163] In some embodiments, the indication of the candidate cell (i.e., from the candidate DU) may be an identifier comprising N1 (integer) bits, which is mapped to a cell identifier of the target candidate cell having N2>N1 bits. For example, a candidate cell configuration (e.g., received from the UE via RRC) may include an N1-bit identifier, such that when the UE receives lower layer signaling including the N1-bit identifier, the UE may match the identifier with the corresponding candidate cell configuration.

[0164] In various embodiments, the indication of the timing offset or adjustment (e.g., from the candidate DU) may be one of:

[0165] A time offset that can be used by the UE to calculate the total time shift between DL and UL frames, which the serving DU must include in the lower layer signaling (e.g. MAC CE) for the UE;

[0166] The total time shift between DL and UL frames, which the serving DU must include in the lower layer signaling (e.g. MAC CE) for the UE; and

[0167] • A complete Timing Advance MAC CE, which the serving DU may send to the UE without modification.

[0168] In some embodiments, the indication of the TCI state (i.e., in the request from the serving DU and in the response from the candidate DU) can be 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.

[0169] 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., SS-RSRP, SS-SINR, SS-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 SSB measurements for different SSB indices for 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 serving DU determines which TCI state (or TCI state identifier) ​​the UE should use in the candidate cell during / after L1 / L2 inter-cell mobility execution. The serving DU includes the identifier of the TCI state in a request to the candidate DU (e.g., sent via the CU).

[0170] Because 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 of the candidate cell and the TCI state (or identifier). This mapping can be provided to the serving DU by the candidate DU or by the CU, in conjunction with or separately from the L1 / L2 mobility process for individual UEs.

[0171] As a more specific example, the candidate DU may provide the following mapping to the serving DU (via the CU):

[0172] SSB index = 3 → TCI status ID = 4;

[0173] SSB index = 2 → TCI status ID = 6;

[0174] SSB index = 7 → TCI status ID = 2;

[0175] If the serving DU receives a report indicating that the UE measured SSB index = 7 of the candidate cell with the strongest SS-RSRP, SS-RSRQ and / or SS-SINR, the serving DU selects TCI state ID = 2 based on the mapping and includes this information in the request to the candidate DU (e.g., via the CU).

[0176] In one option, during the mobility preparation phase of an individual UE, the candidate DU provides mapping to the serving DU via the CU. In the preparation phase, the CU requests the candidate DU to configure the L1 / L2 inter-cell mobility (for at least one candidate target cell) for the UE by sending a UE CONTEXT SETUP REQUEST including an indication that this is a request for L1 / L2 inter-cell mobility. The candidate DU generates and sends a target candidate configuration (including a mapping between an SSB index (or other RS ​​index and / or beam identifier) ​​and a TCI state identifier) ​​to the CU, 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 of a measurement with an SSB index of a candidate cell, the serving DU 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.

[0177] Figure 7 An exemplary 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) (both DUs are associated with the same CU (740)) according to these embodiments is shown. The serving DU, the candidate DU and the CU are physical and / or logical parts of a RAN node (750). Although Figure 7The operations shown in the drawings have numerical labels, but this is for ease of explanation and does not require or imply any particular order of operations unless otherwise explicitly stated.

[0178] 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 for the UE (which is in RRC_CONNECTED state). 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 of the candidate cell. In operation 3, the CU provides the same information to the serving DU of the UE in a DL RRC MESSAGE TRANSFER message. If the CU has collected other candidate cell configurations (e.g., from other candidate DUs), the CU can include these other candidate cell configurations in the message.

[0179] In operation 4-5, the serving DU sends an RRCReconfiguration message including the configuration of the candidate cells for L1 / L2 inter-cell mobility received from the CU to the UE, and the UE responds with an RRCReconfigurationComplete message. In operation 6, the serving DU responds to the CU with an UL RRC MESSAGE TRANSFER message.

[0180] In operation 7, the UE sends one or more CSI reports (or other types of measurement reports) to the serving DU, which have measurements of SSBs in the candidate cell and have the strongest measurement for SSB index = X. In operation 8, 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 (e.g., based on a mapping previously received from the candidate DU or CU, not shown). In operation 9, the serving DU sends a request to the CU for L1 / L2 mobility execution for the UE. The request includes the following information:

[0181] UE CSI report (or relevant parts);

[0182] Identification of candidate cells (i.e., proposed for L1 / L2 mobility execution);

[0183] A request for a TA command to be applied by the UE when accessing a candidate cell; and

[0184] • TCI state ID = Y, which suggests that the UE should perform the operation in the candidate cell.

[0185] In operation 10, the CU forwards the request to the candidate DU, which processes the request and responds in operation 11 with an indication (i.e., confirmation) for L1 / L2 mobility execution, which includes the following information:

[0186] Identification of candidate cells, i.e. for UE L1 / L2 mobility execution;

[0187] TA command applied by the UE when accessing a candidate cell; and

[0188] • TCI State ID = Y, which confirms that the UE should perform the operation in the candidate cell.

[0189] For example, the information may be encapsulated in a message compatible with low layer signaling between the UE and the serving DU. In operation 12, the CU forwards the received information to the serving DU.

[0190] In operations 13-14, the service DU creates low-layer signaling (e.g., MACCE, DCI) using the information received in operation 12 and sends it to the UE. If the received information is encapsulated in a message compatible with the low-layer signaling between the UE and the service DU, the service DU can directly send the message in operation 14. Various other options are discussed below.

[0191] In operation 15, the UE adjusts its UL synchronization and / or timing in the candidate cell based on the TA command (or other timing information) included in the low-layer signaling message. In operation 16, the UE sends an UL message (e.g., data or scheduling request) to the candidate DU in the candidate cell based on applying TCI state ID=Y for the candidate cell. For example, after receiving the low-layer signaling message from the serving DU, the UE adjusts its DL-UL timing offset in the candidate cell based on the TA command before performing its initial UL transmission in the candidate cell based on TCI state ID=7 (operation 16) (operation 15). In this way, the UE is aligned with the candidate cell in UL time and does not need to perform random access before the initial UL transmission.

[0192] In other embodiments, the indication of the TCI state (i.e., in the request from the serving DU and in the response from the candidate DU) 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., SS-RSRP, SS-SINR, SS-RSRQ) for the candidate cell. More specifically, the beam or RS index is configured as the QCL source for the indicated beam configuration.

[0193] For example, the source DU receives one or more measurements of each 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 source 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.

[0194] Because the beam configuration of the candidate cell is generated by the candidate DU serving the cell, the source DU needs to know the mapping between the beam or RS index of the candidate cell and the beam configuration (or identifier). This can be handled in a similar manner to the mapping between the SSB index and the TCI state (or identifier) ​​discussed above.

[0195] In other embodiments, the indication of the TCI state (i.e., in the request from the serving DU and in the response from the candidate DU) is a beam or RS index that identifies the RS (e.g., SSB) as the 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. In particular, the UE selects a TCI state configuration in which the indicated beam or RS index is configured as the QCL source.

[0196] For example, the indicated beam or RS index can be the SSB index for which the UE reports the strongest measurement (e.g., SS-RSRP, SS-SINR, SS-RSRQ) for the candidate cell. The SSB index is configured as the QCL source for a particular TCI state for the candidate cell. In other words, the serving DU receives SSB measurements for different SSB indices of the candidate cell from the UE (e.g., SS-RSRP with SSB index = 1, 5, 7), selects the SSB index corresponding to the strongest measurement, and includes the SSB index in the request for L1 / L2 inter-cell mobility sent to the candidate DU (e.g., via the CU).

[0197] Note that in these embodiments, the serving DU does not perform any mapping between beam or RS (e.g., SSB) indices and TCI states. Instead, the serving DU receives a beam or RS (e.g., SSB) index from the UE, selects the index based on some criteria, sends the selected index to the candidate DU (e.g., via the CU), receives the beam or RS index (which may be the same beam or RS index) in response, and forwards the beam or RS index to the UE in low-layer signaling. Upon receiving the low-layer signaling including the beam or RS index, the UE selects a TCI state in which the beam or RS index (e.g., SSB index) is configured as a QCL source based on the candidate cell configuration previously received by the UE (e.g., from the CU via the serving DU).

[0198] For example, the candidate cell configuration includes the following TCI state configuration for the candidate cell:

[0199] SSB index = 3 as QCL source (e.g. type D) → TCI state ID = 4;

[0200] SSB index = 2 as QCL source (e.g. type D) → TCI state ID = 6;

[0201] SSB index = 7 as QCL source (e.g. type D) → TCI state ID = 2;

[0202] If the serving DU receives a UE report indicating that SSB index = 7 is the SSB with the strongest RSRP, RSRQ and / or SINR for the candidate cell, the serving DU includes SSB index = 7 in a request to the candidate DU (e.g., via the CU), receives a low layer signaling message including SSB index = 7 in response, and forwards the low layer signaling message to the UE. The UE determines that it needs to use TCI state ID = 2 in the candidate cell based on the candidate cell configuration, and for TCI state ID = 2, SSB index = 7 is the QCL source.

[0203] As mentioned above, the serving DU does not need to know the mapping between the SSB index of the candidate cell and the TCI state identifier. Figure 7 Unlike the embodiment shown in , the candidate DU does not need to provide the mapping between the SSB index of the candidate cell and the TCI state identifier to the CU or the serving DU during the preparation phase.

[0204] In some embodiments, upon receiving an indication (e.g., a TA command) of a timing offset or adjustment to be used by the UE to adjust its DL-UL timing offset before performing its initial UL transmission in the candidate cell, the serving DU may use any of the following options (i.e., depending on the form of the lower layer signaling information provided by the candidate DU) when sending this information to the UE:

[0205] An indication of the received timing offset or adjustment is encapsulated in a new MAC CE and sent to the UE before sending a message compatible with lower layer signalling to the candidate cell (containing other parameters required by the UE for L1 / L2 mobility execution);

[0206] The indication of the received timing offset or adjustment is encapsulated in a new MAC CE and sent to the UE after sending a message compatible with lower layer signalling to the candidate cell (containing other parameters required by the UE for L1 / L2 mobility execution);

[0207] The indication of the timing offset or adjustment is received together with other parameters in a message compatible with lower layer signalling, which is forwarded to the UE; or

[0208] The indication of the timing offset and other parameters are in a separate message compatible with lower layer signaling (e.g. MAC CE and / or DCI)

[0209] These messages are forwarded individually to the UE in any of the orders mentioned above.

[0210] In some embodiments, the request for L1 / L2 inter-cell mobility execution sent by the serving DU (operation 9) and the CU (operation 10) may be a UE CONTEXT MODIFICATION REQUEST message on the F1AP. In addition, the indication for performing L1 / L2 inter-cell mobility sent by the candidate DU (operation 11) and the CU (operation 12) may be a UE CONTEXT MODIFICATION RESPONDE message on the F1AP.

[0211] In some embodiments, the UE receives an indication of whether the UE should perform a MAC reset when performing L1 / L2 inter-cell mobility to a candidate cell. In one example, the indication is provided within low layer signaling indicating that L1 / L2 inter-cell mobility to the candidate cell is performed (e.g., operation 14). In another example, the indication is provided within the configuration of one or more L1 / L2 inter-cell mobility candidate cells (e.g., operation 4). In various embodiments, performing a MAC reset may include one or more of the following actions:

[0212] Initialize state variables;

[0213] Stop, start or restart the timer;

[0214] · Setting the New Data Indicator (NDI) for the UL HARQ process to zero;

[0215] Stop the ongoing MAC process;

[0216] Cancel the triggered MAC process;

[0217] ·Flush the message buffer;

[0218] Reset the counter; and

[0219] Release the C-RNTI.

[0220] In some embodiments, the UE selectively performs a MAC reset when performing L1 / L2 inter-cell mobility to a candidate cell, for example, by not performing the actions listed above, performing some or all of the actions listed above. For example, the selective action is based on an indication received from a serving DU, such as the type (e.g., DCI or MAC CE) or content of low-layer signaling indicating the performance of L1 / L2 inter-cell mobility. Alternatively, the indication may be part of a candidate cell configuration received via high-layer signaling.

[0221] 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-configured L1 / L2 inter-cell mobility candidate cells.

[0222] 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-configured L1 / L2 inter-cell mobility candidate cells.

[0223] In some embodiments, the serving 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 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 cell and the candidate target cell are controlled by the same DU. For example, when both the source cell 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 to the candidate cell. In another example, the determination is based on whether both the source cell and the candidate target cell are controlled by the same hardware or software unit.

[0224] In some embodiments, the CU sends an indication to the UE whether the UE needs to perform a MAC reset when performing L1 / L2 inter-cell mobility to 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.

[0225] In some embodiments, the CU receives an indication from a serving DU or a candidate DU 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.

[0226] In some embodiments, the CU sends an indication to the serving DU or the candidate DU 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.

[0227] In some embodiments, the CU 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:

[0228] • Explicit indication from the serving DU or candidate DU.

[0229] • Whether both the source cell and the candidate target cell are controlled by the same DU (eg, when both the source cell and the candidate target cell are controlled by the same DU, the UE does not need to perform a MAC reset).

[0230] • Whether both the source cell and the candidate target cell are controlled by the same hardware or software unit.

[0231] 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.

[0232] 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.

[0233] 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:

[0234] Explicit indication from the serving DU or CU;

[0235] • Whether both the source cell and the candidate target cell are controlled by the same DU (eg, when both the source cell and the candidate target cell are controlled by the same DU, the UE does not need to perform a MAC reset).

[0236] • Whether both the source cell and the candidate target cell are controlled by the same hardware or software unit.

[0237] You can refer to Figure 8-11 To further illustrate the above described embodiments, Figure 8-11 Exemplary methods (eg, processes) for UE, serving DU, candidate DU, and CU are shown, respectively. In other words, various features of the operations described below correspond to the various embodiments described above. Figure 8-11 The exemplary methods shown in the can be used in conjunction to provide benefits, advantages and / or solutions to the problems described herein. Figure 8-11 These exemplary methods are shown by specific blocks in a specific order, but the operations corresponding to the blocks may be performed in a different order than shown, and may be combined and / or divided into operations having functions different from those shown. Optional blocks and / or operations are indicated by dotted lines.

[0238] More specifically, Figure 8 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. Figure 8 The example methods shown in may be performed by a UE (eg, a wireless device) such as described elsewhere herein.

[0239] The exemplary method may include the operation of box 850, wherein the UE may receive one or more low-layer signaling messages from the DU, the one or more low-layer signaling messages indicating that the UE should perform L1 / L2-based inter-cell mobility to a first candidate cell provided by the candidate DU. The one or more low-layer signaling messages include an indicator or identification of the first candidate cell, and an indication of a timing offset or adjustment to be used by the UE in the first candidate cell. In some embodiments, the candidate DU is associated with the CU and / or is part of the RAN node. The exemplary method may also include the operation of box 870, wherein the UE may perform an L1 / L2 mobility procedure toward the first candidate cell and communicate in the first candidate cell based on the timing offset or adjustment.

[0240] In some embodiments, the one or more low layer signaling messages also include an indication of a first transmission configuration indicator (TCI) state to be used by the UE to communicate with the first candidate cell. In such embodiments, communicating in the first candidate cell in block 870 is further based on the first TCI state.

[0241] In some of these embodiments, the indication of the first TCI state is a TCI state identifier. In other of these embodiments, the indication of the first TCI state is an index of a first beam or reference signal (RS) transmitted in the first candidate cell.

[0242] In some variations of these embodiments, the exemplary method may further include operations of blocks 810 and 860. In block 810, 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-located (QCL) source. In block 860, the UE may select 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.

[0243] In some other variations of these embodiments, the exemplary method may further include the operation of block 820, wherein the UE may send an RRCReconfigurationComplete message to the CU via the DU in response to the RRCReconfiguration message. In some other variations of these embodiments, the configuration of the first candidate cell includes an indication of whether the UE should perform a MAC reset when performing L1 / L2 inter-cell mobility to the first candidate cell.

[0244] In some embodiments of these embodiments, the exemplary method may also include operations of blocks 830-840, wherein the UE may perform measurements on multiple beams or RSs transmitted 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 conducive to L1 / L2 mobility to the first candidate cell. In some variations of these embodiments, the multiple beams or RSs (e.g., measured by the UE) include one or more of the following: synchronization signal / PBCH block (SSB), and channel state information reference signal (CSI-RS).

[0245] In some of these embodiments, the indication of the timing offset or adjustment to be used by the UE is one of:

[0246] A time offset that can be used by the UE to calculate the total time shift between the DL frame and the UL frame in the first candidate cell;

[0247] The total time shift between the DL frame and the UL frame in the first candidate cell; and

[0248] · Complete timing advance medium access control (MAC) control element (CE).

[0249] In various variations of these embodiments, the indication of the timing offset or adjustment is received in a first lower layer signaling message, and the indicator or identification of the first candidate cell and the indication of the first TCI state are received in a second lower layer signaling message. In other variations of these embodiments, the indication of the timing offset or adjustment, the indicator or identification of the first candidate cell, and the indication of the first TCI state are received in a single lower layer signaling message.

[0250] In some of these embodiments, communicating in the first candidate cell based on the first TCI state in block 870 includes the following operations (labeled using corresponding sub-block numbers):

[0251] (872) adjusting a downlink-uplink (DL-UL) timing offset for the UE of the first candidate cell based on the timing offset or adjustment; and

[0252] (873) Sending UL data or a scheduling request to the first candidate cell in a beam or spatial direction corresponding to the first TCI state based on the adjusted DL-UL timing offset.

[0253] In some embodiments, the low layer signaling message in block 850 may further include an indication of whether the UE should perform a MAC reset when performing L1 / L2 inter-cell mobility to the first candidate cell. In some of these embodiments, performing the L1 / L2 mobility procedure toward the first candidate cell in block 870 includes operations of sub-block 871, where 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:

[0254] Initialize MAC state variables;

[0255] Stop, start or restart the MAC timer;

[0256] Reset the New Data Indicator (NDI) for the uplink hybrid ARQ process to zero;

[0257] Stop the ongoing MAC process;

[0258] Cancel the MAC process that has been triggered but not in progress;

[0259] ·Flush the MAC message buffer;

[0260] Reset the MAC counter; and

[0261] • Release the Radio Network Temporary Identifier (RNTI) allocated to the UE.

[0262] In some embodiments, one or more of the following apply: each of the one or more low-layer signaling messages is part of a protocol layer below the RRC protocol layer, and each of the one or more low-layer signaling messages is one of the following: a MAC control element (MAC CE), or a PHY downlink control information (DCI). In some embodiments, the candidate DU is associated with a CU and / or is part of a RAN node.

[0263] also, Fig. 9 An exemplary method (eg, process) for a DU of a RAN node according to various embodiments of the present disclosure is shown, the DU being coupled to a CU of the RAN node and configured to provide a serving cell for a UE. Fig. 9 The exemplary methods shown in can be performed by a DU as described elsewhere in this document, for example.

[0264] The exemplary method may include the operation of box 950, where the DU may select a first candidate cell provided by the candidate DU for L1 / L2-based inter-cell mobility of the UE currently served by the DU via the serving cell. The exemplary method may also include the operation of box 970, where the DU may send a request for L1 / L2-based inter-cell mobility of the UE to the CU. The request includes an indicator or identification of the first candidate cell and a request for a timing offset or adjustment to be used by the UE for communication with the first candidate cell. The exemplary method may also include the operation of box 980, where the DU may receive a response from the CU including the following information:

[0265] a message compatible with low layer signaling between the UE and the DU, wherein the message includes an indicator or identity of the first candidate cell; and

[0266] • An indication of the timing offset or adjustment to be used by the UE in the first candidate cell.

[0267] The example method may also include the operation of block 990, where the DU may send one or more lower layer signaling messages to the UE, the one or more lower layer signaling messages indicating that the UE should perform L1 / L2 based inter-cell mobility to the first candidate cell. The one or more lower layer signaling messages include the information received in the response (e.g., in block 980).

[0268] In some embodiments, the request also includes a first indication of a first TCI state recommended for use by the UE to communicate with the first candidate cell, and the message compatible with the lower layer signaling includes a second indication of the first TCI state.

[0269] In some of these embodiments, the example method may further include the operation of block 940, where 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 such an embodiment, selecting the first candidate cell (e.g., in block 950) is based on the measurement result, and the request (e.g., in block 970) also includes at least a portion of the measurement result.

[0270] In some variations of these embodiments, the multiple beams or RSs include one or more of the following: SSBs and CSI-RSs. In some variations of these embodiments, the first TCI state is associated with the first beam or RS having a measurement result that is most favorable for L1 / L2 mobility to the first candidate cell (e.g., the highest SS-RSRP). Additionally, the first indication of the first TCI state is an index of the first beam or RS, or a TCI state identifier. In addition, the second indication of the first TCI state (e.g., in a message compatible with low-layer signaling) is a TCI state identifier.

[0271] In some other variations, the exemplary method may also include the operation of block 960, 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 the first indication; 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 other variations, the exemplary method may also include the operation of block 910, where the DU may receive a mapping from a candidate DU or CU (e.g., used in block 960).

[0272] In some embodiments, the indication of the timing offset or adjustment to be used by the UE (e.g., received in block 980) is one of:

[0273] A time offset that can be used by the UE to calculate the total time shift between the DL frame and the UL frame in the first candidate cell;

[0274] The total time shift between the DL frame and the UL frame in the first candidate cell; and

[0275] · Complete timing advance medium access control (MAC) control element (CE).

[0276] In some of these embodiments, the indication of the timing offset or adjustment is sent to the UE in a first low-layer signaling message, and the received message compatible with the low-layer signaling indicator is sent to the UE as a second low-layer signaling message. In other of these embodiments, the received message compatible with the low-layer signaling includes the indication of the timing offset or adjustment, and the received message is forwarded to the UE as a single low-layer signaling message.

[0277] In some embodiments, the message compatible with the lower layer signaling also includes an indication of whether the UE should perform a MAC reset when performing L1 / L2 inter-cell mobility to the first candidate cell.

[0278] In some embodiments, each of the one or more low-layer signaling messages is part of a protocol layer below the RRC protocol layer. In some embodiments, each of the one or more low-layer signaling messages is one of: a MAC CE, or a PHY DCI. In some embodiments, the candidate DU is associated with a CU and / or is part of a RAN node.

[0279] In some embodiments, the exemplary method may also include the operations of blocks 920-930, wherein the DU may receive from the CU a configuration of one or more candidate cells for L1 / L2-based inter-cell mobility for the UE, the one or more candidate cells including a first candidate cell; and send the configuration to the UE in an RRCReconfiguration message. In some of these embodiments, the configuration for the first candidate cell includes an indication of whether the UE should perform a MAC reset when performing L1 / L2 inter-cell mobility to the first candidate cell. In other embodiments of these embodiments, a message compatible with low layer signaling (e.g., in block 980) includes an indication of whether the UE should perform a MAC reset when performing L1 / L2 inter-cell mobility to the first candidate cell.

[0280] also, Fig.10 An exemplary method (eg, process) for candidate DUs of a RAN node according to various embodiments of the present disclosure is shown, the candidate DUs being coupled to a CU of the RAN node. Fig.10 The exemplary methods shown in can be performed by a DU as described elsewhere in this document, for example.

[0281] The exemplary method may include the operation of block 1040, wherein the candidate DU may receive from the CU a request for L1 / L2 based inter-cell mobility for a UE served by the DU via a serving cell. The request includes an indicator or identification of a first candidate cell and a request for a timing offset or adjustment to be used by the UE to communicate with the first candidate cell. In some embodiments, the DU is associated with the CU and / or is part of a RAN node. The exemplary method may also include the operation of block 1060, wherein the candidate DU may send a response to the CU including the following information:

[0282] a message compatible with low layer signaling between the UE and the DU, wherein the message includes an indicator or identity of the first candidate cell; and

[0283] • An indication of the timing offset or adjustment to be used by the UE in the first candidate cell.

[0284] The example method may also include the operations of block 1070, where the candidate DU may communicate with a UE in the first candidate cell based on the indicated timing offset or adjustment.

[0285] In some embodiments, the request also includes a first indication of a first TCI state recommended for the UE to use to communicate with the first candidate cell, the message compatible with the low layer signaling includes a second indication of the first TCI state, and communicating with the UE in the first candidate cell (e.g., in box 1070) is further based on the first TCI state.

[0286] In some of these embodiments, the first indication of the first TCI state is an index of a first beam or RS transmitted in the first candidate cell. In such embodiments, the exemplary method may also include the operation of block 1050, where the candidate DU may determine the first TCI state or an identifier of the first TCI state 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 transmitted in the first candidate cell.

[0287] In other embodiments of these embodiments, the first indication of the first TCI state is a TCI state identifier, and the exemplary method also includes the operation of box 1010, 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 transmitted in the first candidate cell to the CU or DU.

[0288] In some of these embodiments, the second indication of the first TCI state (eg, in a message compatible with lower layer signaling) is a TCI state identifier.

[0289] In some embodiments of these embodiments, communicating with a UE in a first candidate cell based on the indicated timing offset or adjustment and the first TCI state in box 1070 includes operation of sub-box 1071, wherein the candidate DU can receive uplink data or a scheduling request from the UE in the first candidate cell in a beam or spatial direction corresponding to the first TCI state and at a timing corresponding to the indicated timing offset or adjustment.

[0290] In some embodiments, the request (e.g., in block 1040) further includes results of measurements performed by the UE on a plurality of beams or RSs transmitted in the first candidate cell. In some embodiments, the indication of the timing offset or adjustment to be used by the UE (e.g., sent in block 1060) is one of:

[0291] A time offset that can be used by the UE to calculate the total time shift between the DL frame and the UL frame in the first candidate cell;

[0292] The total time shift between the DL frame and the UL frame in the first candidate cell; or

[0293] Full Timing Advance MAC CE.

[0294] In some of these embodiments, the indication of the timing offset or adjustment and the message compatible with the lower layer signaling are separate in block 1060. In other of these embodiments, in block 1060, the message compatible with the lower layer signaling includes the indication of the timing offset or adjustment.

[0295] In some embodiments, the exemplary method may further include operations of blocks 1020-1030, wherein the candidate DU may receive from the CU a request for configuring the UE with at least one candidate cell for L1 / L2-based inter-cell mobility, and send to the CU a configuration for one or more candidate cells provided by the candidate DU, the one or more candidate cells including a first candidate cell. In some of these embodiments, the configuration of the first candidate cell (e.g., sent in block 1030) includes an indication of whether the UE should perform a MAC reset when performing L1 / L2 inter-cell mobility to the first candidate cell. In other of these embodiments, the message compatible with the lower layer signaling (e.g., sent in block 1060) also includes an indication of whether the UE should perform a MAC reset when performing L1 / L2 inter-cell mobility to the first candidate cell.

[0296] In some embodiments, the message compatible with low layer signaling between the UE and the DU is one of: MAC CE, or PHY DCI.

[0297] also, Fig.11An exemplary method (eg, process) for a CU of a RAN node according to various embodiments of the present disclosure is shown, the CU being coupled to a plurality of DUs of the RAN node. Fig.11 The exemplary methods shown in can be performed by a CU as described elsewhere in this document, for example.

[0298] The exemplary method may include the operation of block 1130, where the CU may receive a request for L1 / L2-based inter-cell mobility for the UE from a DU serving the UE in a serving cell. The request may include the following items:

[0299] An indicator or identity of a first candidate cell for L1 / L2 based inter-cell mobility of the UE, wherein the first candidate cell is served by the candidate DU; and

[0300] a request for a timing offset or adjustment to be used by the UE for communicating with the first candidate cell;

[0301] The example method may also include the operations of blocks 1150-1160, where the CU may forward the request to the candidate DU and receive a response from the candidate DU including the following information:

[0302] a message compatible with low layer signaling between the UE and the DU, wherein the message includes an indicator or identity of the first candidate cell; and

[0303] • An indication of the timing offset or adjustment to be used by the UE in the first candidate cell.

[0304] The example method may also include the operation of block 1170, where the CU may forward the response to the DU.

[0305] In some embodiments, the exemplary method may further include: the CU performs the following operations (labeled with corresponding box numbers):

[0306] (1110) sending a request to the candidate DU for configuring at least one candidate cell for L1 / L2 based inter-cell mobility for the UE;

[0307] (1120) receiving, from 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

[0308] (1130) Send configurations for one or more candidate cells to the DU.

[0309] In some of these embodiments, the configuration for the first candidate cell (e.g., in blocks 1120-1130) includes an indication of whether the UE should perform a MAC reset when performing L1 / L2 inter-cell mobility to the first candidate cell. In other of these embodiments, the message compatible with the low layer signaling (e.g., in blocks 1160-1170) also includes an indication of whether the UE should perform a MAC reset when performing L1 / L2 inter-cell mobility to the first candidate cell.

[0310] In some embodiments, the request also includes a first indication of a first TCI state recommended for use by the UE to communicate with the first candidate cell, and the message compatible with the lower layer signaling includes a second indication of the first TCI state.

[0311] In some of these embodiments, the first indication of the first TCI state is a TCI state identifier or an index of a first beam or RS transmitted in the first candidate cell. In some of these embodiments, the second indication of the first TCI state is a TCI state identifier.

[0312] In some embodiments, the request also includes results of measurements performed by the UE on a plurality of beams or RSs transmitted in the first candidate cell. In some embodiments, the indication of the timing offset or adjustment to be used by the UE (e.g., received in block 1160) is one of:

[0313] A time offset that can be used by the UE to calculate the total time shift between the DL frame and the UL frame in the first candidate cell;

[0314] The total time shift between the DL frame and the UL frame in the first candidate cell; and

[0315] Full Timing Advance MAC CE.

[0316] In some of these embodiments, the indication of the timing offset or adjustment and the message compatible with the lower layer signaling are separate in block 1160. In other of these embodiments, in block 1160, the message compatible with the lower layer signaling includes the indication of the timing offset or adjustment.

[0317] In some embodiments, the message compatible with low layer signaling between the UE and the DU is one of: MAC CE or PHY DCI.

[0318] Although various embodiments are described above in terms of methods, techniques, and / or processes, those skilled in the art 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.

[0319] Fig.12 An example of a communication system 1200 according to some embodiments is shown. In this example, the communication system 1200 includes a telecommunications network 1202, which includes an access network 1204 (e.g., a RAN) and a core network 1206 (which includes one or more core network nodes 1208). The access network 1204 includes one or more access network nodes, such as network nodes 1210a-b (one or more of which may be generally referred to as network nodes 1210), or any other similar 3GPP access nodes or non-3GPP access points. The network nodes 1210 facilitate direct or indirect connection of UEs, such as connecting UEs 1212a-d (one or more of which may be generally referred to as UEs 1212) to the core network 1206 via one or more wireless connections.

[0320] 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 transmitting information without the use of wires, cables, or other material conductors. In addition, in different embodiments, the communication system 1200 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that can facilitate or participate in the communication of data and / or signals (whether via a wired connection or a wireless connection). The communication system 1200 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar types of systems.

[0321] UE 1212 may be any of a variety of communication devices, including wireless devices that are arranged, configured and / or operable to wirelessly communicate with network node 1210 and other communication devices. Similarly, network node 1210 is arranged, capable, configured and / or operable to communicate directly or indirectly with UE 1212 and / or other network nodes or devices in telecommunication network 1202 to enable and / or provide network access (e.g., wireless network access) and / or perform other functions (e.g., management) in telecommunication network 1202.

[0322] In the depicted example, the core network 1206 connects the network node 1210 to one or more hosts, such as the host 1216. These connections may be direct connections, or indirect connections via one or more intermediate networks or devices. In other examples, the network node may be directly coupled to the host. The core network 1206 includes one or more core network nodes (e.g., 1208) composed of hardware and software components. The features of these components may be substantially similar to those described for the UE, network nodes, and / or hosts, so that their descriptions are generally applicable to the corresponding components of the core network node 1208. The example core network node includes one or more functions of: 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).

[0323] The host 1216 may be under the ownership or control of a service provider other than the operator or provider of the access network 1204 and / or the telecommunications network 1202, and may be operated by or on behalf of the service provider. The host 1216 may host various applications to provide one or more services. Examples of such applications include real-time and pre-recorded audio / video content, data collection services (e.g., obtaining and compiling data of 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.

[0324] Overall, Fig.12 The communication system 1200 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 future 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 (WiMax), Bluetooth, Z-wave, Near Field Communication (NFC), ZigBee, LiFi, and / or any Low Power Wide Area Network (LPWAN) standards, such as LoRa and Sigfox.

[0325] In some examples, telecommunication network 1202 is a cellular network implementing 3GPP standardized features. Thus, telecommunication network 1202 may support network slicing to provide different logical networks to different devices connected to telecommunication network 1202. For example, telecommunication network 1202 may 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 other UEs.

[0326] In some examples, UE 1212 is configured to send and / or receive information without direct human interaction. For example, the UE may be designed to send information to access network 1204 on a predetermined schedule when triggered by an internal or external event or in response to a request from access network 1204. Additionally, the UE may be configured to operate in a single RAT or multi-RAT or multi-standard mode. For example, the UE may operate using any one or a combination of Wi-Fi, NR (New Radio), and LTE, i.e., configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved UMTS Terrestrial Radio Access Network) New Radio-Dual Connectivity (EN-DC).

[0327] In this example, the hub 1214 communicates with the access network 1204 to facilitate indirect communication between one or more UEs (e.g., UE 1212c and / or 1212d) and a network node (e.g., network node 1210b). In some examples, the hub 1214 may be a controller, a router, a content source and analysis, or any other communication device described herein with respect to the UE. For example, the hub 1214 may be a broadband router that enables the UE to access the core network 1206. As another example, the hub 1214 may be a controller that sends commands or instructions to one or more actuators in the UE. The commands or instructions may be received from the UE, the network node 1210, or received by an executable code, a script, a process, or other instructions in the hub 1214. As another example, the hub 1214 may be a data collector that acts as a temporary storage device for UE data, and in some embodiments, analysis or other processing of the data may be performed. As another example, the hub 1214 may be a content source. For example, for a UE that is a VR head-mounted device, display, speaker, or other media delivery device, the hub 1214 can obtain VR assets, video, audio, or other media or data related to the sensory information via the network node, and then the hub 1214 provides it to the UE directly, after performing local processing, and / or after adding additional local content. In another example, the hub 1214 acts as a proxy server or orchestrator for the UE, especially when one or more UEs are low-energy IoT devices.

[0328] Hub 1214 can have constant / persistent or intermittent connection with network node 1210b. Hub 1214 can also allow different communication schemes and / or scheduling between hub 1214 and UE (e.g., UE 1212c and / or 1212d) and hub 1214 and core network 1206. In other examples, hub 1214 is connected to core network 1206 and / or one or more UEs via a wired connection. In addition, hub 1214 can be configured to connect to M2M service provider and / or connect to another UE via direct connection through access network 1204. In some scenarios, UE can establish wireless connection with network node 1210 while still connected via hub 1214 through wired or wireless connection. In some embodiments, hub 1214 can be a dedicated hub, that is, a hub whose main function is to route communication from network node 1210b to UE / from UE to network node 1210b. In other embodiments, the hub 1214 may be a non-dedicated hub, that is, a device that is operable to route communications between UEs and the network node 1210b, but is also capable of operating as a communications origin and / or endpoint for a particular data channel.

[0329] Fig.13 A UE 1300 according to some embodiments is shown. Examples of UEs 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, playback devices, wearable terminal devices, wireless endpoints, mobile stations, tablet computers, laptop computers, laptop embedded equipment (LEE), laptop mounted equipment (LME), smart devices, wireless client equipment (CPE), in-vehicle or in-vehicle embedded / integrated wireless devices, etc. Other examples include any UE identified by 3GPP, including narrowband Internet of Things (NB-IoT) UEs, machine type communication (MTC) UEs, and / or enhanced MTC (eMTC) UEs.

[0330] The UE may support device-to-device (D2D) communications, for example, 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. Rather, a UE may represent a device that is intended to be sold to or operated by a human user but may not be, or may not initially be, associated with a particular human user (e.g., a smart sprinkler controller). 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 power meter).

[0331] UE 1300 includes processing circuitry 1302, which is operatively coupled to input / output interface 1306, power supply 1308, memory 1310, communication interface 1312, and / or any other components or any combination thereof via bus 1304. A particular UE may utilize Fig.13 All or a subset of the components shown in . The level of integration between components may vary from UE to UE. In addition, a particular UE may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0332] The processing circuit 1302 is configured to process instructions and data, and may be configured to implement any sequential state machine operable to execute instructions stored as a machine-readable computer program in the memory 1310. The processing circuit 1302 may be implemented as one or more hardware-implemented state machines (e.g., using discrete logic, field programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), etc.); programmable logic and appropriate firmware; one or more stored computer programs, general-purpose processors (e.g., microprocessors or digital signal processors (DSPs)) and appropriate software; or any combination of the above. For example, the processing circuit 1302 may include multiple central processing units (CPUs).

[0333] In this example, the input / output interface 1306 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 1300. Examples of input devices include touch-sensitive displays or presence-sensitive displays, cameras (e.g., digital cameras, digital video cameras, web cameras, etc.), microphones, sensors, mice, trackballs, direction pads, trackpads, rollers, smart cards, etc. The 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.

[0334] In some embodiments, the power supply 1308 is configured as a battery or 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 1308 may also include a power supply circuit for transmitting power from the power supply 1308 itself and / or an external power supply to various parts of the UE 1300 via an input circuit or interface (e.g., a power cord). The transmitted power may be used, for example, to charge the power supply 1308. The power supply circuit may perform any formatting, conversion, or other modification of the power from the power supply 1308 to make the power suitable for the corresponding components of the UE 1300 to which the power is provided.

[0335] The memory 1310 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 cassette, a flash drive, etc. In one example, the memory 1310 includes one or more application programs 1314 (e.g., an operating system, a web browser application, a widget, a widget engine, or other application) and corresponding data 1316. The memory 1310 may store any one of a variety of operating systems or a combination of operating systems for use by the UE 1300.

[0336] The memory 1310 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 disc (HD-DVD) optical drive, an internal hard drive, a Blu-ray optical drive, a holographic digital data storage (HDDS) optical drive, an external mini dual in-line memory module (DIMM), a synchronous dynamic random access memory (SDRAM), an external micro-DIMM SDRAM, a smart card memory (e.g., 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 1310 may allow the UE 1300 to access instructions, applications, etc. stored on a temporary or non-temporary storage medium to offload data or upload data. An article of manufacture, such as utilizing a communication system, may be tangibly embodied as or in memory 1310, which may be or include a device-readable storage medium.

[0337] The processing circuit 1302 may be configured to communicate with an access network or other network using a communication interface 1312. The communication interface 1312 may include one or more communication subsystems and may include an antenna 1322 or be communicatively coupled to the antenna 1322. The communication interface 1312 may include one or more transceivers for communication (e.g., 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 1318 and / or a receiver 1320 suitable for providing network communications (e.g., optical, electrical, frequency allocation, etc.). In addition, the transmitter 1318 and the receiver 1320 may be coupled to one or more antennas (e.g., 1322), and may share circuit components, software, or firmware, or may be implemented separately instead.

[0338] In the illustrated embodiment, the communication functionality of the communication interface 1312 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 functionality, or any combination thereof. 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 network (SONET), asynchronous transfer mode (ATM), QUIC, hypertext transfer protocol (HTTP), etc.

[0339] 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 1312. The data captured by the UE's sensor may be transmitted via another UE via a wireless connection to a network node. The output may be periodic (e.g., every 15 minutes if it reports the sensed temperature), random (e.g., to balance the reporting load from multiple sensors), in response to a trigger event (e.g., sending an alarm when humidity 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).

[0340] As another example, the UE includes an actuator, motor, or switch associated with a communication interface that is 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 controls a robotic arm performing a medical procedure based on the received input.

[0341] When in the form of an Internet of Things (IoT) device, a UE may be a device for one or more application areas including, but not limited to, urban wearable technology, extended industry applications, and healthcare. Non-limiting examples of such IoT devices are devices that are or are embedded in: a connected refrigerator or freezer, a television, 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 / humidity sensor, an electric 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 teleoperated surgical robot. A UE in the form of an IoT device includes circuits and / or software related to the intended application of the IoT device such as for Fig.13 Other components described for UE 1300 shown in .

[0342] 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 sends 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 (e.g., a car, bus, truck), a ship, and an airplane, or other device that is capable of monitoring and / or reporting its operating status or other functions associated with its operation.

[0343] In practice, any number of UEs may be used together for a single use case. For example, a first UE may be or be integrated into a drone and provide the drone's speed information (obtained via a speed sensor) to a second UE that is a remote controller for operating the drone. When the user makes changes 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 UE and / or the second UE may also include multiple of the functions described above. For example, a UE may include a sensor and an actuator and handle data communications for both the speed sensor and the actuator.

[0344] Fig.14 A network node 1400 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).

[0345] Base stations may be classified based on the amount of coverage they provide (or in other words, their transmit power class), 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 (e.g., 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).

[0346] Other examples of network nodes include a multi-transmission point (multi-TRP) 5G access node, a multi-standard radio MSR device (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 positioning center (E-SMLC)) and / or a minimization of drive tests (MDT).

[0347] The network node 1400 includes a processing circuit 1402, a memory 1404, a communication interface 1406, and a power supply 1408. The network node 1400 may include multiple physically separated components (e.g., a node B component and an RNC component, or a BTS component and a BSC component, etc.), each of which may have its own corresponding components. In a specific scenario where the network node 1400 includes multiple separate components (e.g., a BTS and a BSC component), one or more separate components may be shared between multiple network nodes. For example, a single RNC may control multiple node Bs. In such a scenario, in some cases, each unique node B and RNC pair may be considered as a single separate network node. In some embodiments, the network node 1400 may be configured to support multiple radio access technologies (RATs). In such an embodiment, some components may be repeated (e.g., separate memories 1404 for different RATs), while some components may be reused (e.g., the same antenna 1410 may be shared by different RATs). The network node 1400 may also include various sets of example components for different wireless technologies (e.g., GSM, WCDMA, LTE, NR, Wi-Fi, Zigbee, Z-wave, LoRaWAN, radio frequency identification (RFID), or Bluetooth wireless technologies) integrated into the network node 1400. These wireless technologies may be integrated into the same or different chips or chipsets and other components within the network node 1400.

[0348] The processing circuit 1402 may include a combination of one or more of the following operable to provide network node 1400 functionality, alone or in combination with other network node 1400 components (e.g., memory 1404): 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.

[0349] In some embodiments, processing circuitry 1402 includes a system on a chip (SOC). In some embodiments, processing circuitry 1402 includes one or more of radio frequency (RF) transceiver circuitry 1412 and baseband processing circuitry 1414. In some embodiments, RF transceiver circuitry 1412 and baseband processing circuitry 1414 may be on separate chips (or chipsets), boards, or units (e.g., a radio unit and a digital unit). In alternative embodiments, some or all of RF transceiver circuitry 1412 and baseband processing circuitry 1414 may be on the same chip or chipset, board, or unit.

[0350] The memory 1404 may include any form of volatile or non-volatile computer-readable memory, including but not limited to permanent 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 storage device that stores information, data and / or instructions that can be used by the processing circuit 1402. The memory 1404 may store any suitable instructions, data or information, including computer programs, software, applications (including one or more of logic, rules, codes, tables, etc.) and / or other instructions that can be executed by the processing circuit 1402 and utilized by the network node 1400 (collectively represented as computer program 1404a, which may take the form of a computer program product). The memory 1404 may be used to store any calculations performed by the processing circuit 1402 and / or any data received via the communication interface 1406. In some embodiments, processing circuit 1402 and memory 1404 are integrated.

[0351] The communication interface 1406 is used for the wired or wireless communication of signaling and / or data between network nodes, access networks and / or UEs. As shown, the communication interface 1406 includes a port / terminal 1416 to send and receive data to the network, for example, via a wired connection. The communication interface 1406 also includes a radio front-end circuit 1418 that can be coupled to an antenna 1410 or as a part of an antenna 1410 in a specific embodiment. The radio front-end circuit 1418 includes a filter 1420 and an amplifier 1422. The radio front-end circuit 1418 can be connected to the antenna 1410 and the processing circuit 1402. The radio front-end circuit 1418 can be configured to adjust the signal transmitted between the antenna 1410 and the processing circuit 1402. The radio front-end circuit 1418 can receive digital data that will be sent to other network nodes or UEs via a wireless connection. The radio front-end circuit 1418 can use a combination of a filter 1420 and / or an amplifier 1422 to convert digital data into a radio signal with appropriate channel and bandwidth parameters. The radio signal can then be transmitted via the antenna 1410. Similarly, when receiving data, antenna 1410 may collect radio signals, which may then be converted into digital data by radio front end circuitry 1418. The digital data may be passed to processing circuitry 1402. In other embodiments, the communication interface may include different components and / or different combinations of components.

[0352] In certain alternative embodiments, the network node 1400 does not include a separate radio front end circuit 1418, but rather, the processing circuit 1402 includes the radio front end circuit and is connected to the antenna 1410. Similarly, in some embodiments, all or part of the RF transceiver circuit 1412 is part of the communication interface 1406. In other embodiments, the communication interface 1406 includes one or more ports or terminals 1416, the radio front end circuit 1418, and the RF transceiver circuit 1412 as part of a radio unit (not shown), and the communication interface 1406 communicates with the baseband processing circuit 1414, which is part of the digital unit (not shown).

[0353] Antenna 1410 may include one or more antennas or antenna arrays configured to send and / or receive wireless signals. Antenna 1410 may be coupled to radio front end circuit 1418 and may be any type of antenna capable of wirelessly sending and receiving data and / or signals. In a particular embodiment, antenna 1410 is separate from network node 1400 and may be connected to network node 1400 via an interface or port.

[0354] Antenna 1410, communication interface 1406 and / or processing circuit 1402 may be configured to perform any receiving operation and / or specific obtaining operation 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 1410, communication interface 1406 and / or processing circuit 1402 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.

[0355] The power supply 1408 provides power to the various components of the network node 1400 in a form suitable for the respective components (e.g., at the voltage and current levels required by each respective component). The power supply 1408 may also include or be coupled to a power management circuit to provide power to the components of the network node 1400 for performing the functions described herein. For example, the network node 1400 may be connected to an external power source (e.g., a power grid, a power outlet) via an input circuit or interface (e.g., a cable), whereby the external power source provides power to the power circuit of the power supply 1408. As yet another example, the power supply 1408 may include a power source in the form of a battery or battery pack connected to or integrated into the power circuit. If the external power source fails, the battery may provide backup power.

[0356] An embodiment of the network node 1400 may include Fig.14Additional components beyond those shown that are used to provide specific 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 1400 may include a user interface device to allow information to be input into the network node 1400 and to allow information to be output from the network node 1400. This may allow a user to perform diagnostics, maintenance, repair, and other management functions for the network node 1400.

[0357] Fig.15 is a block diagram of a host 1500 according to various aspects described herein, and the host 1500 may be Fig.12 1216 of the embodiment of the host. As used herein, the host 1500 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 farm. The host 1500 can provide one or more services to one or more UEs.

[0358] Host 1500 includes processing circuitry 1502, which is operatively coupled to input / output interface 1506, network interface 1508, power supply 1510, and memory 1512 via bus 1504. 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 (e.g., Fig.13 and 14 ) so that its description is generally applicable to corresponding components of host 1500.

[0359] The memory 1512 may include one or more computer programs, including one or more host applications 1514 and data 1516, which may include user data, such as data generated by a UE for the host 1500 or data generated by the host 1500 for the UE. An embodiment of the host 1500 may utilize some or all of the components shown. The host application 1514 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 of multiple different classes, types, or implementations of UEs (e.g., mobile phones, desktop computers, wearable display systems, head-up display systems). The host application 1514 may also provide user authentication and authorization checks, and may periodically report health status, routing, and content availability to a central node (e.g., a device in a core network or on the edge). Thus, the host 1500 can select and / or indicate to the UE a different host for the over-the-top service. The host application 1514 can 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.

[0360] Fig.16 1600 is a block diagram showing a virtualized environment 1600 in which functions implemented by some embodiments can be virtualized. In the current context, virtualization means creating a virtual version of a device or equipment, which may include a virtualized hardware platform, storage device, and networking resources. As used herein, virtualization may be applied to any device or component thereof described herein, and relates to an 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 1600 hosted by one or more hardware nodes (e.g., hardware computing devices operating as network nodes, UEs, core network nodes, or hosts). In addition, in embodiments in which a virtual node does not require a radio connection (e.g., a core network node or host), the node may be fully virtualized.

[0361] Application 1602 (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 1600 to implement certain features, functions and / or benefits of some embodiments disclosed herein.

[0362] The hardware 1604 includes processing circuitry, memory storing software and / or instructions (collectively referred to as computer program product 1604a) 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 1606 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide virtual machines 1608a and 1608b (one or more of which may be generally referred to as virtual machines 1608), and / or perform any of the functions, features, and / or benefits described for some embodiments described herein. The virtualization layer 1606 may present a virtual operating platform that appears to be networked hardware to the virtual machine 1608.

[0363] The virtual machine 1608 includes virtual processing, virtual memory, virtual network or interface, and virtual storage, and can be run by a corresponding virtualization layer 1606. Different embodiments of instances of virtual devices 1602 can be implemented on one or more virtual machines 1608 and can be implemented in different ways. In some contexts, virtualization of hardware is referred to as network function virtualization (NFV). NFV can be used to integrate many network device types onto industry-standard high-volume server hardware, physical switches, and physical storage that can be located in data centers and client devices.

[0364] In the context of NFV, each virtual machine 1608 can be a software implementation of a physical machine that runs a program as if the program were executed on a physical, non-virtualized machine. Each virtual machine 1608 and the portion of the hardware 1604 that executes the virtual machine (hardware dedicated to the virtual machine and / or hardware shared by the virtual machine with other virtual machines) form a separate virtual network unit. Still in the context of NFV, a virtual network function is responsible for handling a specific network function running in one or more virtual machines 1608 on the hardware 1604 and corresponds to an application 1602.

[0365] Hardware 1604 can be implemented in a stand-alone network node with general or specific components. Hardware 1604 can implement some functions via virtualization. Alternatively, hardware 1604 can 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 1610, which, among other items, oversees the life cycle management of application 1602. In some embodiments, hardware 1604 is coupled to one or more radio units, each of which includes one or more transmitters and one or more receivers that can be coupled to one or more antennas. The radio unit can communicate directly with other hardware nodes via one or more appropriate network interfaces, and can 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 1612 can be used to provide some signaling, which can be used alternatively for communication between hardware nodes and radio units.

[0366] Fig.17 A communication diagram is shown in which a host 1702 communicates with a UE 1706 via a network node 1704 over a partially wireless connection according to some embodiments. Fig.17 To describe the UE (eg, Fig.12 UE 1212a and / or Fig.13 UE 1300), network node (e.g. Fig.12 The network node 1210a and / or Fig.14 network nodes 1400) and hosts (e.g. Fig.12 Host 1216 and / or Fig.15 An example implementation of host 1500).

[0367] Similar to the host 1500, an embodiment of the host 1702 includes hardware, such as a communication interface, a processing circuit, and a memory. The host 1702 also includes software that is stored in the host 1702 or accessible by the host 1702 and can be executed by the processing circuit. The software includes a host application that can operate to provide services to a remote user (e.g., a UE 1706 connected via an over-the-top (OTT) connection 1750 extending between the UE 1706 and the host 1702). When providing services to the remote user, the host application can provide user data sent using the OTT connection 1750.

[0368] The network node 1704 includes hardware that enables it to communicate with the host 1702 and the UE 1706. The connection 1760 can be direct or through a core network (such as Fig.12The core network 1206 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.

[0369] UE 1706 includes hardware and software, which is stored in UE 1706 or accessible by UE 1706 and can be executed by the processing circuit of UE. The software includes a client application, such as a web browser or an operator-specific "application", which is operable to provide services to human or non-human users via UE 1706 with the support of host 1702. In host 1702, the executing host application can communicate with the executing client application via an OTT connection 1750 terminated at UE 1706 and host 1702. When providing services to users, the client application of UE can receive request data from the host application of the host and provide user data in response to the request data. OTT connection 1750 can transmit both request data and user data. The client application of UE can interact with the user to generate user data provided to the host application via OTT connection 1750.

[0370] The OTT connection 1750 may extend via a connection 1760 between the host 1702 and the network node 1704 and via a wireless connection 1770 between the network node 1704 and the UE 1706 to provide connectivity between the host 1702 and the UE 1706. The connection 1760 and the wireless connection 1770 through which the OTT connection 1750 may be provided have been drawn abstractly to illustrate communications between the host 1702 and the UE 1706 via the network node 1704 without explicit reference to any intermediate devices and the precise routing of messages via those devices.

[0371] As an example of sending data via the OTT connection 1750, in step 1708, the host 1702 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 who interacts with the UE 1706. In other embodiments, the user data is associated with the UE 1706, and the UE 1706 shares data with the host 1702 without explicit human interaction. In step 1710, the host 1702 initiates a transmission carrying the user data toward the UE 1706. The host 1702 may initiate the transmission in response to a request sent by the UE 1706. The request may be caused by human interaction with the UE 1706 or by the operation of a client application executed on the UE 1706. According to the teachings of the embodiments described throughout the present disclosure, the transmission may be through the network node 1704. Therefore, in step 1712, according to the teachings of the embodiments described throughout the present disclosure, the network node 1704 sends the user data carried in the transmission initiated by the host 1702 to the UE 1706. In step 1714 , UE 1706 receives user data carried in the transmission, which may be performed by a client application executing on UE 1706 that is associated with a host application executed by host 1702 .

[0372] In some examples, UE 1706 executes a client application that provides user data to host 1702. The user data may be provided in response to data received from host 1702. Therefore, in step 1716, UE 1706 may provide user data, which may be performed by executing the client application. In providing the user data, the client application may further consider user input received from the user via the input / output interface of UE 1706. Regardless of the specific manner in which the user data is provided, UE 1706 initiates transmission of the user data toward host 1702 via network node 1704 in step 1718. In step 1720, in accordance with the teachings of the embodiments described throughout the present disclosure, network node 1704 receives user data from UE 1706 and initiates transmission of the received user data toward host 1702. In step 1722, host 1702 receives the user data carried in the transmission initiated by UE 1706.

[0373] One or more of the various embodiments improves the performance of OTT services provided to UE 1706 using OTT connection 1750 (wherein wireless connection 1770 forms the last segment). More precisely, the embodiments described herein can more reliably facilitate the execution of L1 / L2 inter-cell mobility because the execution phase is completed in coordination with the candidate DU and / or CU. Therefore, when the UE receives low-layer signaling indicating the execution of L1 / L2 inter-cell mobility, the signaling comes directly from the candidate DU of the candidate cell that the serving UE will enter. These advantages are achieved in the following manner: the UE is provided with a TA indication (e.g., a command) and TCI state information (e.g., a 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, 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 interruptions when the MAC reset is unnecessary. At a high level, the embodiments improve mobility in a RAN (e.g., an NG-RAN). By improving the operation of the UE and RAN in this way, embodiments increase the value of OTT services delivered to / from the UE via the RAN.

[0374] In an example scenario, host 1702 may collect and analyze plant status information. As another example, host 1702 may process audio and video data that may have been obtained from a UE for use in creating a map. As another example, host 1702 may collect and analyze real-time data to assist in controlling vehicle congestion (e.g., controlling traffic lights). As another example, host 1702 may store surveillance videos uploaded by a UE. As another example, host 1702 may store or control access to media content such as video, audio, VR, or AR, and host 1702 may broadcast, multicast, or unicast the media content to a UE. As other examples, host 1702 may be used for energy pricing, remote control of non-time-critical power loads to balance power generation demand, positioning services, presentation services (e.g., editing a map based on data collected from a remote device, etc.), or any other function for collecting, obtaining, storing, analyzing, and / or sending data.

[0375] In some examples, a measurement process may be provided for the purpose of monitoring data rates, delays, and other factors on which one or more embodiments are improved. In response to changes in the measurement results, there may also be an optional network function for reconfiguring the OTT connection 1750 between the host 1702 and the UE 1706. The measurement process and / or network function for reconfiguring the OTT connection may be implemented in the software and hardware of the host 1702 and / or the UE 1706. In some embodiments, sensors (not shown) may be deployed in other devices through which the OTT connection 1750 passes or associated with such other devices; the sensors may participate in the measurement process by providing the values ​​of the monitored quantities of the above examples or providing the values ​​of other physical quantities from which the software can calculate or estimate the monitored quantities. The reconfiguration of the OTT connection 1750 may include message formats, retransmission settings, preferred routes, etc.; the reconfiguration does not require direct changes to the operation of the network node 1704. Such processes and functions may be known and practiced in the art. In a particular embodiment, the measurement may involve proprietary UE signaling, which facilitates the host 1702 to measure throughput, propagation time, delay, etc. Measurement can be achieved because the software causes the OTT connection 1750 to be used to send messages, particularly empty or "dummy" messages, during which it monitors propagation times, errors, etc.

[0376] The above merely illustrates the principles of the present disclosure. In view of the teachings herein, various modifications and changes to the described embodiments will be apparent to those skilled in the art. It should therefore be understood that those skilled in the art will be able to design a variety of systems, arrangements, and processes that, although not explicitly shown or described herein, embody the principles of the present disclosure and are therefore within the spirit and scope of the present disclosure. As will be appreciated by those of ordinary skill in the art, the various embodiments may be used together with each other, and may be used interchangeably with each other.

[0377] The above merely illustrates the principles of the present disclosure. In view of the teachings herein, various modifications and changes to the described embodiments will be apparent to those skilled in the art. It should therefore be understood that those skilled in the art will be able to design a variety of systems, arrangements, and processes that, although not explicitly shown or described herein, embody the principles of the present disclosure and are therefore within the spirit and scope of the present disclosure. As will be appreciated by those of ordinary skill in the art, the various embodiments may be used together with each other, and may be used interchangeably with each other.

[0378] As used herein, the term "unit" may have its 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. as described herein.

[0379] Any appropriate steps, methods, features, functions or benefits disclosed herein may be performed by one or more functional units or modules of one or more virtual devices. Each virtual device may include multiple such 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 implementations, a processing circuit may be used to cause a corresponding functional unit to perform a corresponding function according to one or more embodiments of the present disclosure.

[0380] 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 function of the device or apparatus is not implemented by hardware but is implemented as a software module (e.g., a computer program or computer program product including an executable software code portion 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 an assembly of multiple devices and / or apparatuses, whether they are functionally cooperative or independent of each other. In addition, as long as the functions of the device or apparatus are retained, the device and apparatus may be implemented in a distributed manner throughout the system. Such and similar principles are considered to be known to those skilled in the art.

[0381] 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 being performed by a single physical device and may actually be distributed across multiple physical devices.

[0382] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by those of ordinary skill in the art to which the present disclosure belongs. It will be further 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 should not be interpreted as an idealized or overly formal meaning, unless explicitly defined as such herein.

[0383] In addition, certain terms used in this disclosure (including the specification and drawings) may be used synonymously in certain cases (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 situations where such words may not be intended to be used synonymously.

[0384] The techniques and devices described herein include, but are not limited to, the following examples:

[0385] A1. 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, the method comprising:

[0386] Receiving one or more low layer signaling messages from the DU, the one or more low layer signaling messages indicating that the UE should perform L1 / L2 based inter-cell mobility to a first candidate cell provided by the candidate DU, wherein the one or more low layer signaling messages include:

[0387] an indicator or identification of the first candidate cell, and

[0388] an indication of a timing offset or adjustment to be used by the UE in the first candidate cell;

[0389] An L1 / L2 mobility procedure is performed toward a first candidate cell, and communication is performed in the first candidate cell based on the timing offset or adjustment.

[0390] A1a. The method according to embodiment A1, wherein:

[0391] The one or more lower layer signaling messages further include an indication of a first transmission configuration indicator (TCI) state to be used by the UE for communicating with the first candidate cell; and

[0392] Communicating in the first candidate cell is further based on the first TCI state.

[0393] A2. The method of embodiment A1a, wherein the indication of the first TCI state is a TCI state identifier.

[0394] A3. A method according to embodiment A1a, wherein the indication of the first TCI state is an index of the first beam or reference signal RS transmitted in the first candidate cell.

[0395] A4. The method according to embodiment A3 further comprising:

[0396] 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, wherein:

[0397] Each candidate cell configuration includes multiple TCI state configurations, and

[0398] Each TCI state configuration includes an index of a beam or RS arranged as a quasi-co-located QCL source; and

[0399] 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.

[0400] 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.

[0401] A5a. A method according to any one of embodiments A4-A5, wherein the configuration for the first candidate cell includes an indication of whether the UE should perform a media access control (MAC) reset when performing L1 / L2 inter-cell mobility to the first candidate cell.

[0402] A6. The method according to any one of embodiments A1a-A5a, wherein the method further comprises:

[0403] performing measurement on a plurality of beams or reference signals RS transmitted in a first candidate cell; and

[0404] Send the measurement results to DU,

[0405] Among them, 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 to the first candidate cell.

[0406] A7. 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.

[0407] A8. The method of any one of embodiments A1a-A7, wherein the indication of the timing offset or adjustment to be used by the UE is one of:

[0408] a time offset that can be used by the UE to calculate a total time shift between a DL frame and a UL frame in a first candidate cell;

[0409] The total time shift between DL frames and UL frames in the first candidate cell; or

[0410] Complete timing advance medium access control MAC control element CE.

[0411] A9. The method of embodiment A8, wherein one of the following applies:

[0412] The indication of the timing offset or adjustment is received in a first lower layer signaling message, and the indicator or identification of the first candidate cell and the indication of the first TCI state are received in a second lower layer signaling message; or

[0413] The indication of the timing offset or adjustment, the indicator or identification of the first candidate cell, and the indication of the first TCI state are received in a single low layer signaling message.

[0414] A10. The method of any one of embodiments A1a-A9, wherein communicating in the first candidate cell based on the timing offset or adjustment indicated in the low layer signaling message and the first TCI state comprises:

[0415] adjusting a downlink-uplink DL-UL timing offset for UEs of the first candidate cell based on the timing offset or adjustment; and

[0416] Based on the adjusted DL-UL timing offset, UL data or a scheduling request is sent to the first candidate cell in a beam or spatial direction corresponding to the first TCI state.

[0417] A11. A method according to any one of embodiments A1-A10, wherein the low-layer signaling message also includes an indication of whether the UE should perform a media access control MAC reset when performing L1 / L2 inter-cell mobility to the first candidate cell.

[0418] A12. The method of embodiment A11, wherein performing the L1 / L2 mobility process toward 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:

[0419] Initialize MAC state variables;

[0420] Stop, start or restart the MAC timer;

[0421] Resetting the new data indicator NDI for the uplink hybrid ARQ process to zero;

[0422] Stop the ongoing MAC process;

[0423] Cancel the MAC process that has been triggered but not in progress;

[0424] Refresh the MAC message buffer;

[0425] Reset the MAC counter; and

[0426] The radio network temporary identifier RNTI allocated to the UE is released.

[0427] A13. The method of any one of embodiments A1-A12, wherein one or more of the following applies:

[0428] Each of the one or more low layer signaling messages is part of a protocol layer below a radio resource control, RRC, protocol layer; and

[0429] Each of the one or more low layer signaling messages is one of: a MAC control element CE; or a PHY downlink control information DCI.

[0430] A14. A method according to any one of embodiments A1-A13, wherein the candidate DU is associated with a CU and / or is part of a RAN node.

[0431] 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 configured to provide a serving cell for a user equipment UE, the method comprising:

[0432] 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; and

[0433] Sending a request for L1 / L2-based inter-cell mobility of the UE to the CU, wherein the request includes:

[0434] an indicator or identification of the first candidate cell, and

[0435] a request for a timing offset or adjustment to be used by the UE for communicating with the first candidate cell; and

[0436] Receive a response from the CU that includes the following information:

[0437] a message compatible with low layer signaling between the UE and the DU, wherein the message includes an indicator or an identification of the first candidate cell; and

[0438] an indication of a timing offset or adjustment to be used by the UE in the first candidate cell; and

[0439] One or more lower layer signaling messages are sent to the UE, the one or more lower layer signaling messages indicating that the UE should perform L1 / L2 based inter-cell mobility to the first candidate cell, wherein the one or more lower layer signaling messages include the information received in the response.

[0440] B1a. The method according to embodiment B1, wherein:

[0441] The request also includes a first indication of a first transmission configuration indicator (TCI) state proposed for use by the UE to communicate with the first candidate cell; and

[0442] The message compatible with the lower layer signaling includes a second indication of the first TCI state.

[0443] B2. The method according to embodiment B1a, wherein:

[0444] The method further includes: receiving, from the UE, a result of measurement performed by the UE on a plurality of beams or reference signals RS transmitted in the first candidate cell, wherein the measurement result includes corresponding indexes of the plurality of beams or RSs;

[0445] Selecting the first candidate cell is based on the measurement results; and

[0446] The request also includes at least a portion of the measurement results.

[0447] 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.

[0448] B3. According to the method described in any one of embodiments B2-B2a, the first TCI state is associated with the first beam or RS having a measurement result that is most favorable for L1 / L2 mobility to the first candidate cell.

[0449] B4. A method according to embodiment B3, wherein the first indication of the first TCI state is an index of the first beam or RS.

[0450] B5. A method according to embodiment B3, wherein the first indication of the first TCI state is a TCI state identifier.

[0451] B6. The method according to embodiment B5 also includes: determining a TCI state identifier of 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 the index of the beam or RS transmitted in the first candidate cell.

[0452] B7. The method according to embodiment B6 also includes: receiving a mapping from one of the following: a candidate DU, or a CU.

[0453] B7a. The method of any one of embodiments B1a-B7, wherein the second indication of the first TCI state is a TCI state identifier.

[0454] B8. The method of any one of embodiments B1-B7a, wherein the indication of the timing offset or adjustment to be used by the UE is one of:

[0455] a time offset that can be used by the UE to calculate a total time shift between a DL frame and a UL frame in a first candidate cell;

[0456] The total time shift between DL frames and UL frames in the first candidate cell; or

[0457] Complete timing advance medium access control MAC control element CE.

[0458] B9. The method of embodiment B8, wherein one of the following applies:

[0459] An indication of the timing offset or adjustment is sent to the UE in a first lower layer signaling message, and a received message compatible with the lower layer signaling indicator is sent to the UE as a second lower layer signaling message; or

[0460] The received message compatible with the lower layer signaling includes an indication of the timing offset or adjustment, and the received message is forwarded to the UE as a single lower layer signaling message.

[0461] B10. A method according to any one of embodiments B1-B9, wherein the message compatible with the low-layer signaling also includes an indication of whether the UE should perform a media access control (MAC) reset when performing L1 / L2 inter-cell mobility to the first candidate cell.

[0462] B11. The method of any one of embodiments B1-B10, wherein one or more of the following applies:

[0463] Each of the one or more low layer signaling messages is part of a protocol layer below a radio resource control, RRC, protocol layer; and

[0464] Each of the one or more low layer signaling messages is one of: a MAC control element CE; or a PHY downlink control information DCI.

[0465] B12. A method according to any one of embodiments B1-B11, wherein the candidate DU is associated with a CU and / or is part of a RAN node.

[0466] B13. The method according to any one of embodiments B1-B12, further comprising:

[0467] receiving, from the CU, configuration of one or more candidate cells for L1 / L2-based inter-cell mobility of the UE, the one or more candidate cells including a first candidate cell; and

[0468] The configuration is sent to the UE in the RRCReconfiguration message.

[0469] B14. A method according to embodiment B13, wherein the configuration of 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.

[0470] 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:

[0471] receiving, from the CU, a request for L1 / L2-based inter-cell mobility for a UE currently served by the DU via a serving cell, wherein the request comprises:

[0472] an indicator or identification of the first candidate cell, and

[0473] a request for a timing offset or adjustment for the UE to use for communicating with the first candidate cell;

[0474] Send a response to the CU including the following information:

[0475] a message compatible with low layer signaling between the UE and the DU, wherein the message includes an indicator or an identification of the first candidate cell; and

[0476] an indication of a timing offset or adjustment to be used by the UE in the first candidate cell; and

[0477] Based on the indicated timing offset or adjustment, communicating with the UE in the first candidate cell.

[0478] C2. The method according to embodiment C1, wherein:

[0479] The request also includes a first indication of a first transmission configuration indicator (TCI) state proposed for use by the UE to communicate with the first candidate cell;

[0480] The message compatible with the lower layer signaling includes a second indication of the first TCI state; and

[0481] Communicating with the UE in the first candidate cell is further based on the first TCI state.

[0482] C3. The method according to embodiment C2, wherein:

[0483] The first indication of the first TCI state is an index of a first beam or reference signal RS transmitted in a first candidate cell; and

[0484] The method also includes: determining a first TCI state or an identifier of the first TCI state based on the following items: an 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 transmitted in the first candidate cell.

[0485] C4. A method according to embodiment C2, wherein the first indication of the first TCI state is a TCI state identifier.

[0486] C5. The method according to embodiment C4 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.

[0487] C6. A method according to any one of embodiments C2-C5, wherein the second indication of the first TCI state is a TCI state identifier.

[0488] C6a. A method according to any one of embodiments C2-C6, wherein, based on the indicated timing offset or adjustment and the first TCI state, communicating with the UE in the first candidate cell includes: receiving uplink data or a scheduling request from the UE in the first candidate cell in a beam or spatial direction corresponding to the first TCI state and at a timing corresponding to the indicated timing offset or adjustment.

[0489] C7. A method according to any one of embodiments C1-C6a, wherein the request also includes results of measurements performed by the UE on multiple beams or reference signals RS transmitted in the first candidate cell.

[0490] C8. The method of any one of embodiments C1-C7, wherein the indication of the timing offset or adjustment to be used by the UE is one of:

[0491] a time offset that can be used by the UE to calculate a total time shift between a DL frame and a UL frame in a first candidate cell;

[0492] The total time shift between DL frames and UL frames in the first candidate cell; or

[0493] Complete timing advance medium access control MAC control element CE.

[0494] C9. The method of embodiment C8, wherein one of the following applies:

[0495] The indication of the timing offset or adjustment is separate from the message compatible with the lower layer signalling; or

[0496] Messages compatible with lower layer signaling include indications of timing offsets or adjustments.

[0497] C10. The method according to any one of embodiments C1-C9, further comprising:

[0498] receiving, from the CU, a request for configuring the UE with at least one candidate cell for L1 / L2-based inter-cell mobility; and

[0499] Configurations for one or more candidate cells provided by the candidate DU are sent to the CU, the one or more candidate cells including the first candidate cell.

[0500] C11. The method of embodiment C10, 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.

[0501] C12. The method according to embodiment C10, wherein the message compatible with the low layer signaling further 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.

[0502] C13. A method according to any one of embodiments C1-C12, wherein the message compatible with the low layer signaling between the UE and the DU is one of the following: a MAC control element CE; or PHY downlink control information DCI.

[0503] C14. A method according to any one of embodiments C1-C13, wherein the DU is associated with the CU and / or is part of the RAN node.

[0504] D1. A method for a central unit CU of a radio access network RAN ​​node, the CU being coupled to a plurality of distributed units DU of the RAN node, the method comprising:

[0505] Receiving, from a DU serving the UE in a serving cell, a request for L1 / L2 based inter-cell mobility for the UE, wherein the request comprises:

[0506] An indicator or identification of a first candidate cell for L1 / L2 based inter-cell mobility of the UE, wherein the first candidate cell is served by the candidate DU; and

[0507] a request for a timing offset or adjustment to be used by the UE for communicating with the first candidate cell;

[0508] Forward the request to the candidate DU;

[0509] Receive a response from the candidate DU that includes the following information:

[0510] a message compatible with low layer signaling between the UE and the DU, wherein the message includes an indicator or an identification of the first candidate cell; and

[0511] an indication of a timing offset or adjustment to be used by the UE in the first candidate cell; and

[0512] Forward the response to DU.

[0513] D2. The method according to embodiment D1, further comprising:

[0514] sending a request to the candidate DU for configuring the UE with at least one candidate cell for L1 / L2 based inter-cell mobility;

[0515] receiving, from 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

[0516] A configuration for one or more candidate cells is sent to the DU.

[0517] D3. A method according to embodiment D2, 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.

[0518] D4. A method according to embodiment D2, wherein the message compatible with the low layer signaling also includes an indication of whether the UE should perform a media access control MAC reset when performing L1 / L2 inter-cell mobility to the first candidate cell.

[0519] D5. The method of any one of embodiments D1-D4, wherein:

[0520] The request also includes a first indication of a first transmission configuration indicator (TCI) state proposed for use by the UE to communicate with the first candidate cell; and

[0521] The message compatible with the lower layer signaling includes a second indication of the first TCI state.

[0522] D6. The method of embodiment D5, wherein the first indication of the first TCI state is one of:

[0523] TCI status identifier; or

[0524] The index of the first beam or reference signal RS transmitted in the first candidate cell.

[0525] D7. A method according to any one of embodiments D5-D6, wherein the second indication of the first TCI state is a TCI state identifier.

[0526] D8. A method according to any one of embodiments D1-D7, wherein the request also includes results of measurements performed by the UE on multiple beams or reference signals RS transmitted in the first candidate cell.

[0527] D9. The method of any one of embodiments D1-D8, wherein the indication of the timing offset or adjustment to be used by the UE is one of:

[0528] a time offset that can be used by the UE to calculate a total time shift between a DL frame and a UL frame in a first candidate cell;

[0529] The total time shift between DL frames and UL frames in the first candidate cell; or

[0530] Complete timing advance medium access control MAC control element CE.

[0531] D10. The method of embodiment D9, wherein one of the following applies:

[0532] The indication of the timing offset or adjustment is separate from the message compatible with the lower layer signalling; or

[0533] Messages compatible with lower layer signaling include indications of timing offsets or adjustments.

[0534] D11. A method according to any one of embodiments D1-D10, wherein the message compatible with the low-layer signaling between the UE and the DU is one of the following: a MAC control element CE; or PHY downlink control information DCI.

[0535] E1. 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:

[0536] a communication interface circuit configured to communicate with the CU and at least the DU; and

[0537] A processing circuit is operatively coupled to a 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-A14.

[0538] E2. A user equipment UE is configured to communicate with a radio access network RAN ​​node, the RAN node includes a central unit CU and a distributed unit DU providing a serving cell for the UE, and the UE is also configured to perform operations corresponding to the method described in any one of embodiments A1-A14.

[0539] E3. A non-transitory computer-readable medium storing computer-executable instructions, which, when executed by a processing circuit of a user equipment UE, configures the UE to perform operations corresponding to the method described in any one of embodiments A1-A14, wherein the UE is configured to communicate with a radio access network RAN ​​node, the RAN node including a central unit CU and a distributed unit DU providing a service cell for the UE.

[0540] E4. A computer program product comprising computer executable instructions, which, when executed by a processing circuit of a user equipment UE, configures the UE to perform operations corresponding to the method described in any one of embodiments A1-A14, 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.

[0541] F1. 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 configured to provide a serving cell for a user equipment UE, the DU comprising:

[0542] a communication interface circuit configured to communicate with the CU and the UE; and

[0543] A processing circuit is operatively coupled to a communication interface circuit, whereby the processing circuit and the communication interface circuit are configured to perform operations corresponding to the method of any one of embodiments B1-B14.

[0544] F2. 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 DU being further configured to perform operations corresponding to the method described in any one of embodiments B1-B14.

[0545] F3. 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 described in any one of embodiments B1-B14, 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.

[0546] F4. 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 a method described in any one of embodiments B1-B14, 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.

[0547] G1. 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 candidate DU comprising:

[0548] a communication interface circuit configured to communicate with the CU and the UE via one or more cells provided by the candidate DU; and

[0549] A processing circuit is operatively coupled to the communication interface circuit, whereby the processing circuit and the communication interface circuit are configured to perform operations corresponding to the method of any one of embodiments C1-C14.

[0550] G2. A second distributed unit DU of a radio access network RAN ​​node, which is coupled to a central unit CU of the RAN node, and the second DU is configured to perform operations corresponding to the method described in any one of embodiments C1-C14.

[0551] G3. A non-transitory computer-readable medium storing computer-executable instructions, which, when executed by a processing circuit of a candidate distributed unit DU, configure the candidate DU to perform operations corresponding to the method described in any one of embodiments C1-C14, wherein the candidate DU is coupled to a central unit CU of a radio access network RAN ​​node.

[0552] G4. A computer program product comprising computer executable instructions which, when executed by a processing circuit of a candidate distributed unit DU, configure the candidate DU to perform operations corresponding to the method described in any one of embodiments C1-C14, wherein the candidate DU is coupled to a central unit CU of a radio access network RAN ​​node.

[0553] H1. A central unit CU of a radio access network RAN ​​node, which is coupled to a plurality of distributed units DU of the RAN node, the CU comprising:

[0554] a communication interface circuit configured to communicate with the DU and one or more UEs via a cell provided by the DU; and

[0555] A processing circuit is operatively coupled to the communication interface circuit, whereby the processing circuit and the communication interface circuit are configured to perform operations corresponding to the method of any one of embodiments D1-D11.

[0556] H2. A central unit CU of a radio access network RAN ​​node, which is coupled to multiple distributed units DU of the RAN node, and the CU is configured to perform operations corresponding to the method described in any one of embodiments D1-D11.

[0557] H3. A non-temporary computer-readable medium storing computer-executable instructions, which, when executed by a processing circuit of a central unit CU of a radio access network RAN ​​node, configure the CU to perform operations corresponding to a method described in any one of embodiments D1-D11, wherein the CU is coupled to multiple distributed units DU of the RAN node.

[0558] H4. A computer program product comprising computer executable instructions, which, when executed by a processing circuit of a central unit CU of a radio access network RAN ​​node, configure the CU to perform operations corresponding to the method described in any one of embodiments D1-D11, wherein the CU is coupled to multiple distributed units DU of the RAN node.

Claims

1. 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, the method comprising: Receiving (850) one or more low layer signaling messages from the DU, the one or more low layer signaling messages indicating that the UE should perform L1 / L2 based inter-cell mobility to a first candidate cell provided by the candidate DU, wherein the one or more low layer signaling messages include: an indicator or identification of the first candidate cell, and an indication of a timing offset or adjustment to be used by the UE in the first candidate cell; An L1 / L2 mobility procedure is performed (870) toward the first candidate cell, and communicating in the first candidate cell based on the timing offset or adjustment.

2. The method according to claim 1, wherein: The one or more low layer signaling messages further include an indication of a first transmission configuration indicator (TCI) state to be used by the UE for communicating with the first candidate cell; and Communicating (870) in the first candidate cell is further based on the first TCI state.

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

4. The method according to claim 3, further comprising: receiving (810) 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 A TCI state configuration including the index of the first beam or RS as a QCL source among the TCI state configurations is selected (860) as the first TCI state.

5. The method according to claim 4, further comprising: In response to the RRCReconfiguration message, an RRCReconfigurationComplete message is sent (820) to the CU via the DU.

6. The method according to any one of claims 4 to 5, wherein: The configuration associated with 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.

7. The method according to any one of claims 2 to 6, wherein: The method further comprises: performing (830) measurements on a plurality of beams or reference signals RS transmitted in the first candidate cell; and sending (840) 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 to the first candidate cell.

8. The method according to claim 7, 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.

9. The method according to any one of claims 2 to 8, wherein: The indication of the timing offset or adjustment to be used by the UE is one of: a time offset usable by the UE to calculate a total time shift between a downlink DL frame and an uplink UL frame in the first candidate cell; The total time shift between DL frames and UL frames in the first candidate cell; or Complete timing advance medium access control MAC control element CE.

10. The method according to claim 9, wherein: One of the following applies: said indication of a timing offset or adjustment is received in a first lower layer signaling message, and said indicator or identification of said first candidate cell and said indication of said first TCI state are received in a second lower layer signaling message; or The indication of the timing offset or adjustment, the indicator or identification of the first candidate cell, and the indication of the first TCI state are received in a single low layer signaling message.

11. The method according to any one of claims 2 to 10, wherein: Communicating in the first candidate cell based on the timing offset or adjustment indicated in the low layer signaling message and the first TCI state (870) includes: adjusting (872) a downlink-uplink DL-UL timing offset for the UE for the first candidate cell based on the timing offset or adjustment; and Based on the adjusted DL-UL timing offset, UL data or a scheduling request is sent (873) to the first candidate cell in a beam or spatial direction corresponding to the first TCI state.

12. The method according to any one of claims 1 to 11, wherein: The low layer signaling message also includes 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.

13. The method according to claim 12, wherein: Performing (870) the L1 / L2 mobility procedure towards the first candidate cell includes selectively performing (871) 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 in progress; Refresh the MAC message buffer; Reset the MAC counter; and A radio network temporary identifier RNTI allocated to the UE is released.

14. The method according to any one of claims 1 to 13, wherein: One or more of the following applies: Each of the one or more low layer signaling messages is part of a protocol layer below a radio resource control, RRC, protocol layer; as well as Each of the one or more low layer signaling messages is one of: a medium access control MAC control element CE; or physical layer downlink control information DCI.

15. The method according to any one of claims 1 to 14, wherein: The candidate DU is associated with the CU and / or is part of the RAN node.

16. 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 (950) 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; as well as sending (970) a request for L1 / L2-based inter-cell mobility of the UE to the CU, wherein the request includes: an indicator or identification of the first candidate cell, and a request for a timing offset or adjustment to be used by the UE for communicating with the first candidate cell; and receiving (980) a response from the CU including: a message compatible with low layer signaling between the UE and the DU, wherein the message includes the indicator or identification of the first candidate cell; and an indication of a timing offset or adjustment to be used by the UE in the first candidate cell; and Sending (990) one or more low layer signaling messages to the UE, the one or more low layer signaling messages indicating that the UE should perform L1 / L2 based inter-cell mobility to the first candidate cell, wherein the one or more low layer signaling messages include the information received in the response.

17. The method of claim 16, wherein: The request further includes a first indication of a first transmission configuration indicator (TCI) state proposed for use by the UE to communicate with the first candidate cell; and The message compatible with low layer signaling includes a second indication of the first TCI state.

18. The method of claim 17, wherein: The method further includes: receiving (940) from the UE a result of measurement performed by the UE on a plurality of beams or reference signals RS transmitted in the first candidate cell, wherein the measurement result includes respective indexes of the plurality of beams or RSs; Selecting (950) the first candidate cell is based on the measurement result; and The request also includes at least a portion of the measurement results.

19. The method according to claim 18, 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.

20. The method according to any one of claims 18-19, wherein: The first TCI state is associated with a first beam or RS having a measurement result most favorable for L1 / L2 mobility to the first candidate cell; The first indication of the first TCI state is one of: the index of the first beam or RS, or a TCI state identifier; and The second indication of the first TCI state is a TCI state identifier.

21. The method according to claim 20, further comprising: The TCI state identifier for the first TCI state is determined (960) based on: the index of the first beam or RS, which is the first indication; as well as 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.

22. The method according to claim 21, further comprising: The mapping is received (910) from the candidate DU or the CU.

23. The method according to any one of claims 16 to 22, wherein: The indication of the timing offset or adjustment to be used by the UE is one of: a time offset usable by the UE to calculate a total time shift between a downlink DL frame and an uplink UL frame in the first candidate cell; The total time shift between DL frames and UL frames in the first candidate cell; or Complete timing advance medium access control MAC control element CE.

24. The method according to claim 23, wherein: One of the following applies: said indication of a timing offset or adjustment is sent to said UE in a first lower layer signaling message, and said received message compatible with the lower layer signaling indicator is sent to said UE as a second lower layer signaling message; or The received message compatible with the lower layer signaling comprises said indication of the timing offset or adjustment and the received message is forwarded to said UE as a single lower layer signaling message.

25. The method according to any one of claims 16 to 24, wherein: One or more of the following applies: Each of the one or more low layer signaling messages is part of a protocol layer below a radio resource control, RRC, protocol layer; as well as Each of the one or more low layer signaling messages is one of: a medium access control MAC control element CE; or physical layer downlink control information DCI.

26. The method according to any one of claims 16 to 25, wherein: The candidate DU is associated with the CU and / or is part of the RAN node.

27. The method according to any one of claims 16 to 26, further comprising: receiving (920) from the CU a configuration of one or more candidate cells for L1 / L2 based inter-cell mobility for the UE, the one or more candidate cells including the first candidate cell; and The configuration is sent (930) to the UE in an RRCReconfiguration message.

28. The method according to claim 27, wherein: One of the following 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: the configuration for the first candidate cell, or the message compatible with low layer signaling.

29. 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: A request for L1 / L2 based inter-cell mobility for a user equipment UE served by the DU via a serving cell is received (1040) from the CU, wherein the request comprises: an indicator or identification of a first candidate cell for L1 / L2 based inter-cell mobility for the UE, and a request for a timing offset or adjustment for the UE to communicate with the first candidate cell; A response including the following information is sent (1060) to the CU: a message compatible with low layer signaling between the UE and the DU, wherein the message includes the indicator or identification of the first candidate cell; and an indication of a timing offset or adjustment to be used by the UE in the first candidate cell; and Based on the indicated timing offset or adjustment, communicate with the UE in the first candidate cell (1070).

30. The method of claim 29, wherein: The request further includes a first indication of a first transmission configuration indicator (TCI) state proposed for use by the UE to communicate with the first candidate cell; The message compatible with lower layer signaling includes a second indication of the first TCI state; and Communicating (1070) with the UE in the first candidate cell is further based on the first TCI state.

31. The method of claim 30, wherein: The first indication of the first TCI state is an index of a first beam or reference signal RS transmitted in the first candidate cell; as well as The method also includes: determining (1050) the first TCI state or an identifier of the first TCI state based on the following items: 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 transmitted in the first candidate cell.

32. The method of claim 30, wherein: The first indication of the first TCI state is a TCI state identifier; as well as The method also includes sending (1010) to the CU or 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.

33. The method according to any one of claims 30 to 32, wherein: The second indication of the first TCI state is a TCI state identifier.

34. The method according to any one of claims 30 to 33, wherein: Based on the indicated timing offset or adjustment and the first TCI state, communicating (1070) with the UE in the first candidate cell includes receiving (1071) uplink data or a scheduling request from the UE in the first candidate cell in a beam or spatial direction corresponding to the first TCI state and at a timing corresponding to the indicated timing offset or adjustment.

35. The method according to any one of claims 29 to 34, wherein: The request also includes results of measurements performed by the UE on a plurality of beams or reference signals RS transmitted in the first candidate cell.

36. The method according to any one of claims 29 to 35, wherein: The indication of the timing offset or adjustment to be used by the UE is one of: a time offset usable by the UE to calculate a total time shift between a downlink DL frame and an uplink UL frame in the first candidate cell; The total time shift between DL frames and UL frames in the first candidate cell; or Complete timing advance medium access control MAC control element CE.

37. The method of claim 36, wherein: One of the following applies: said indication of a timing offset or adjustment and said message compatible with lower layer signalling are separate; or Said message being compatible with lower layer signalling comprises said indication of a timing offset or adjustment.

38. The method according to any one of claims 29 to 37, further comprising: receiving (1020) from the CU a request for configuring the UE with at least one candidate cell for L1 / L2 based inter-cell mobility; as well as A configuration for one or more candidate cells provided by the candidate DU is sent (1030) to the CU, the one or more candidate cells including the first candidate cell.

39. The method of claim 38, wherein: One of the following 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: the configuration for the first candidate cell, or the message compatible with low layer signaling.

40. The method according to any one of claims 29 to 39, wherein: The message compatible with the low layer signaling between the UE and the DU is one of: a medium access control MAC control element CE; or physical layer downlink control information DCI.

41. The method according to any one of 29-40, wherein The DU is associated with the CU and / or is part of the RAN node.

42. A method for a central unit CU of a radio access network RAN ​​node, the CU being configured to communicate with a plurality of distributed units DU of the RAN node, the method comprising: A request for L1 / L2-based inter-cell mobility for a user equipment UE is received (1140) from a DU serving the UE in a serving cell, wherein the request includes: An indicator or identification of a first candidate cell for L1 / L2 based inter-cell mobility of the UE, wherein the first candidate cell is served by the candidate DU; and a request for a timing offset or adjustment to be used by the UE for communicating with the first candidate cell; forwarding (1150) the request to the candidate DU; A response is received (1160) from the candidate DU including the following information: a message compatible with low layer signaling between the UE and the DU, wherein the message includes the indicator or identification of the first candidate cell; and an indication of a timing offset or adjustment to be used by the UE in the first candidate cell; and The response is forwarded (1170) to the DU.

43. The method of claim 42, further comprising: sending (1110) to the candidate DU a request for configuring the UE with at least one candidate cell for L1 / L2 based inter-cell mobility; receiving (1120) from 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; as well as The configuration for the one or more candidate cells is sent (1130) to the DU.

44. The method of claim 43, wherein: One of the following 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: the configuration of the first candidate cell, or the message compatible with low layer signaling.

45. The method according to any one of claims 42 to 44, wherein: The request further includes a first indication of a first transmission configuration indicator (TCI) state proposed for use by the UE to communicate with the first candidate cell; and The message compatible with low layer signaling includes a second indication of the first TCI state.

46. ​​The method of claim 45, wherein: One or more of the following applies: The first indication of the first TCI state is one of: a TCI state identifier, or an index of a first beam or a reference signal RS transmitted in the first candidate cell; and The second indication of the first TCI state is a TCI state identifier.

47. The method according to any one of claims 42 to 46, wherein: The request also includes results of measurements performed by the UE on a plurality of beams or reference signals RS transmitted in the first candidate cell.

48. The method according to any one of claims 42 to 47, wherein: The indication of the timing offset or adjustment to be used by the UE is one of: a time offset usable by the UE to calculate a total time shift between a downlink DL frame and an uplink UL frame in the first candidate cell; The total time shift between DL frames and UL frames in the first candidate cell; or Complete timing advance medium access control MAC control element CE.

49. The method of claim 48, wherein: One of the following applies: said indication of a timing offset or adjustment and said message compatible with lower layer signalling are separate; or Said message being compatible with lower layer signalling comprises said indication of a timing offset or adjustment.

50. The method according to any one of claims 42 to 49, wherein: The message compatible with the low layer signaling between the UE and the DU is one of: a medium access control MAC control element CE; or physical layer downlink control information DCI.

51. A user equipment UE (510, 710, 1212, 1300, 1706) configured to communicate with a radio access network RAN ​​node (100, 550, 750, 1210, 1400, 1602, 1704), 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 (1312) configured to communicate with the CU and at least the DU; as well as A processing circuit (1302) operatively coupled to the communication interface circuit, wherein the processing circuit and the communication interface circuit are configured to: receiving one or more low layer signaling messages from the DU, the one or more low layer signaling messages indicating that the UE should perform L1 / L2 based inter-cell mobility to a first candidate cell provided by the candidate DU, wherein the one or more low layer signaling messages include: an indicator or identification of the first candidate cell, and an indication of a timing offset or adjustment to be used by the UE in the first candidate cell; An L1 / L2 mobility procedure is performed towards the first candidate cell, and communication is performed in the first candidate cell based on the timing offset or adjustment.

52. The UE according to claim 51, wherein: The processing circuit and the communication interface circuit are further configured to perform operations corresponding to the method of any one of claims 2-15.

53. A user equipment UE (510, 710, 1212, 1300, 1706), configured to communicate with a radio access network RAN ​​node (100, 550, 750, 1210, 1400, 1602, 1704), 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 one or more low layer signaling messages from the DU, the one or more low layer signaling messages indicating that the UE should perform L1 / L2 based inter-cell mobility to a first candidate cell provided by the candidate DU, wherein: The one or more low-layer signaling messages include: an indicator or identification of the first candidate cell, and an indication of a timing offset or adjustment to be used by the UE in the first candidate cell; An L1 / L2 mobility procedure is performed towards the first candidate cell, and communication is performed in the first candidate cell based on the timing offset or adjustment.

54. The UE according to claim 53 is further configured to perform operations corresponding to the method according to any one of claims 2-15.

55. A non-transitory computer-readable medium (1310) storing computer-executable instructions, which, when executed by a processing circuit (1302) of a user equipment UE (510, 710, 1212, 1300, 1706), configure the UE to perform operations corresponding to the method of any one of claims 1-15, wherein the UE is configured to communicate with a radio access network RAN ​​node (100, 550, 750, 1210, 1400, 1602, 1704), 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.

56. A computer program product (1314) comprising computer executable instructions, which, when executed by a processing circuit (1302) of a user equipment UE (510, 710, 1212, 1300, 1706), configure the UE to perform operations corresponding to the method of any one of claims 1-15, the UE being configured to communicate with a radio access network RAN ​​node (100, 550, 750, 1210, 1400, 1602, 1704), 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.

57. A distributed unit DU (120, 520, 720) of a radio access network RAN ​​node (100, 550, 750, 1210, 1400, 1602, 1704), 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, 1212, 1300, 1706), the DU comprising: a communication interface circuit (1406, 1604) configured to communicate with the CU and the UE; as well as a processing circuit (1402, 1604) operatively 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 for L1 / L2-based inter-cell mobility of a UE served by the DU via the serving cell; as well as Sending a request for L1 / L2-based inter-cell mobility for the UE to the CU, wherein the request includes: an indicator or identification of the first candidate cell, and a request for a timing offset or adjustment to be used by the UE to communicate with the first candidate cell; and A response is received from the CU including the following information: a message compatible with low layer signaling between the UE and the DU, wherein the message includes the indicator or identification of the first candidate cell; and an indication of a timing offset or adjustment to be used by the UE in the first candidate cell; and and sending one or more low layer signaling messages to the UE, the one or more low layer signaling messages indicating that the UE should perform L1 / L2 based inter-cell mobility to the first candidate cell, wherein the one or more low layer signaling messages include the information received in the response.

58. The DU of claim 57, wherein: The processing circuit and the communication interface circuit are further configured to perform operations corresponding to the method of any one of claims 17-28.

59. A distributed unit DU (120, 520, 720) of a radio access network RAN ​​node (100, 550, 750, 1210, 1400, 1602, 1704), 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, 1212, 1300, 1706), the DU being further configured to: selecting a first candidate cell provided by a candidate DU for L1 / L2-based inter-cell mobility of a UE served by the DU via the serving cell; as well as sending a request for L1 / L2-based inter-cell mobility for the UE to the CU, wherein: The request includes: an indicator or identification of the first candidate cell, and a request for a timing offset or adjustment to be used by the UE to communicate with the first candidate cell; and receiving a response from the CU including: a message compatible with low layer signaling between the UE and the DU, wherein the message includes the indicator or identification of the first candidate cell; and an indication of a timing offset or adjustment to be used by the UE in the first candidate cell; and and sending one or more low layer signaling messages to the UE, the one or more low layer signaling messages indicating that the UE should perform L1 / L2 based inter-cell mobility to the first candidate cell, wherein the one or more low layer signaling messages include the information received in the response.

60. The DU of claim 59, further configured to perform operations corresponding to the method of any one of claims 17-28.

61. A non-transitory computer-readable medium (1404, 1604) 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, 1210, 1400, 1602, 1704), configure the DU to perform operations corresponding to the method of any one of claims 16-28.

62. A computer program product (1404a, 1604a) 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, 1210, 1400, 1602, 1704), configure the DU to perform operations corresponding to the method of any one of claims 16-28.

63. A candidate distributed unit DU (130, 530, 730) of a radio access network RAN ​​node (100, 550, 750, 1210, 1400, 1602, 1704), 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 (1406, 1604) configured to communicate with the CU and with a user equipment UE (510, 710, 1212, 1300, 1706) via one or more cells provided by the candidate DU; as well as a processing circuit (1402, 1604) operatively coupled to the communication interface circuit, whereby the processing circuit and the communication interface circuit are configured to: receiving, from the CU, a request for L1 / L2-based inter-cell mobility for a UE served by a DU (120, 520, 720) via a serving cell, wherein the request comprises: an indicator or identification of a first candidate cell for L1 / L2 based inter-cell mobility of the UE, and a request for a timing offset or adjustment for the UE to communicate with the first candidate cell; Send a response to the CU including the following information: a message compatible with low layer signaling between the UE and the DU, wherein the message includes the indicator or identification of the first candidate cell; and an indication of a timing offset or adjustment to be used by the UE in the first candidate cell; and Communicate with the UE in the first candidate cell based on the indicated timing offset or adjustment.

64. The candidate DU according to claim 63, wherein: The processing circuit and the communication interface circuit are further configured to perform operations corresponding to the method of any one of claims 30-41.

65. A candidate distributed unit DU (130, 530, 730) of a radio access network RAN ​​node (100, 550, 750, 1210, 1400, 1602, 1704), 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: A request for L1 / L2-based inter-cell mobility for a user equipment UE (510, 710, 1212, 1300, 1706) served by a DU (120, 520, 720) via a serving cell is received from the CU, wherein: The request includes: an indicator or identification of a first candidate cell for L1 / L2 based inter-cell mobility of the UE, and a request for a timing offset or adjustment for the UE to communicate with the first candidate cell; Send a response to the CU including the following information: a message compatible with low layer signaling between the UE and the DU, wherein the message includes the indicator or identification of the first candidate cell; and an indication of a timing offset or adjustment to be used by the UE in the first candidate cell; and Communicate with the UE in the first candidate cell based on the indicated timing offset or adjustment.

66. The candidate DU according to claim 65 is further configured to perform operations corresponding to the method of any one of claims 30-41.

67. A non-transitory computer-readable medium (1404, 1604) storing computer-executable instructions, which, when executed by a processing circuit (1402, 1604) of a candidate distributed unit DU (130, 530, 730) of a radio access network RAN ​​node (100, 550, 750, 1210, 1400, 1602, 1704), configure the candidate DU to perform operations corresponding to the method of any one of claims 29-41.

68. A computer program product (1404a, 1604a) comprising computer executable instructions, which, when executed by a processing circuit (1402, 1604) of a candidate distributed unit DU (130, 530, 730) of a radio access network RAN ​​node (100, 550, 750, 1210, 1400, 1602, 1704), configure the candidate DU to perform operations corresponding to the method of any one of claims 29-41.

69. A central unit CU (110, 540, 740) of a radio access network RAN ​​node (100, 550, 750, 1210, 1400, 1602, 1704), the CU being configured to communicate with a plurality of distributed units DU (120, 130, 520, 530, 720, 730) of the RAN node, the CU comprising: a communication interface circuit (1406, 1604) configured to communicate with the DU and with one or more user equipments UE (510, 710, 1212, 1300, 1706) via a cell provided by the DU; as well as a processing circuit (1402, 1604) operatively coupled to the communication interface circuit, whereby the processing circuit and the communication interface circuit are configured to: receiving, from a DU serving a UE in a serving cell, a request for L1 / L2-based inter-cell mobility for the UE, wherein the request comprises: An indicator or identification of a first candidate cell for UE inter-cell mobility based on L1 / L2, wherein: The first candidate cell is served by a candidate DU; and a request for a timing offset or adjustment to be used by the UE for communicating with the first candidate cell; forwarding the request to the candidate DU; A response is received from the candidate DU including the following information: a message compatible with low layer signaling between the UE and the DU, wherein the message includes the indicator or identification of the first candidate cell; and an indication of a timing offset or adjustment to be used by the UE in the first candidate cell; and The response is forwarded to the DU.

70. The CU of claim 69, wherein: The processing circuit and the communication interface circuit are further configured to perform operations corresponding to the method of any one of claims 43-50.

71. A central unit CU (110, 540, 740) of a radio access network RAN ​​node (100, 550, 750, 1210, 1400, 1602, 1704), the CU being configured to communicate with a plurality of distributed units DU (120, 130, 520, 530, 720, 730) of the RAN node, the CU being further configured to: A request for L1 / L2-based inter-cell mobility for a user equipment UE (510, 710, 1212, 1300, 1706) is received from a DU serving the UE in a serving cell, wherein: The request includes: An indicator or identification of a first candidate cell for L1 / L2 based inter-cell mobility of the UE, wherein the first candidate cell is served by the candidate DU; and a request for a timing offset or adjustment to be used by the UE for communicating with the first candidate cell; forwarding the request to the candidate DU; A response is received from the candidate DU including the following information: a message compatible with low layer signaling between the UE and the DU, wherein the message includes the indicator or identification of the first candidate cell; and an indication of a timing offset or adjustment to be used by the UE in the first candidate cell; and The response is forwarded to the DU.

72. The CU according to claim 71 is further configured to perform operations corresponding to the method of any one of claims 43-50.

73. A non-transitory computer-readable medium (1404, 1604) storing computer-executable instructions, which, when executed by a processing circuit (1402, 1604) of a central unit CU (110, 540, 740) of a radio access network RAN ​​node (100, 550, 750, 1210, 1400, 1602, 1704), configure the CU to perform operations corresponding to the method of any one of claims 42-50.

74. A computer program product (1404a, 1604a) comprising computer executable instructions, which, when executed by a processing circuit (1402, 1604) of a central unit CU (110, 540, 740) of a radio access network RAN ​​node (100, 550, 750, 1210, 1400, 1602, 1704), configure the CU to perform operations corresponding to the method of any one of claims 42-50.

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