TCI state operation for L1L2 triggered mobility

Abstract

The present invention relates to a user equipment, UE, including the following. A transceiver of a UE receives configuration information for configuring a set of beam indicators, the set of beam indicators comprising at least one first beam indicator and at least one second beam indicator, the at least one first beam indicator indicates one or more beams available for signal transmission and / or signal reception in a serving cell serving the UE, and wherein the at least one first beam indicator indicates one or more beams available for signal transmission and / or signal reception in a serving cell serving the UE, the at least one second beam indicator indicates one or more candidate beams available for signaling and / or signal reception after handover from the serving cell to a target candidate cell, the target candidate cell being one of the one or more candidate cells participating in mobility of the UE. Processing circuitry of the UE configures a set of beam indicators obtained from the configuration information.

Description

Technical Field

[0001] This disclosure relates to methods, apparatus and articles of manufacture in communication systems such as 3GPP communication systems. Background Technology

[0002] Currently, the 3rd Generation Partnership Project (3GPP) is working on the technical specifications of new radio access technology – 5G NR (New Radio) (also known as fifth generation (5G) or NR, and the terms are used interchangeably in this document).

[0003] One goal is to provide a single technology framework (see, for example, Section 6 of 3GPP TR 38.913, version 16.0.0 or 17.0.0) that addresses all use cases, requirements, and deployment scenarios, including at least enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine-type communication (mMTC). For example, eMBB deployment scenarios could include indoor hotspots, dense urban areas, rural areas, urban macros, and highways; URLLC deployment scenarios could include industrial control systems, mobile healthcare (remote monitoring, diagnosis, and treatment), real-time vehicle control, and wide-area monitoring and control systems for smart grids; and mMTC deployment scenarios could include scenarios with a large number of devices transmitting non-time-critical data, such as smart wearables and sensor networks. Serving eMBB and URLLC is similar because they both require very wide bandwidth; however, they are also different because URLLC services may preferably require ultra-low latency.

[0004] The second goal is to achieve forward compatibility, which facilitates entirely new system designs and / or the introduction of novel features. Summary of the Invention

[0005] A non-limiting and exemplary embodiment helps the central unit of a base station perform an improved mobility process.

[0006] A non-limiting and exemplary embodiment helps a UE perform an improved mobility process. In one embodiment, the technology disclosed herein is characterized by a user equipment (UE) comprising the following: The UE's transceiver receives configuration information for configuring a set of beam indicators, wherein the set of beam indicators includes at least one first beam indicator and at least one second beam indicator, wherein the at least one first beam indicator indicates one or more beams capable of signal transmission and / or signal reception in a serving cell serving the UE, and wherein the at least one second beam indicator indicates one or more candidate beams capable of signal transmission and / or signal reception after a handover from the serving cell to a target candidate cell, the target candidate cell being one of one or more candidate cells participating in the UE's mobility. The UE's processing circuitry configures the set of beam indicators obtained from the configuration information.

[0007] In another embodiment, the technology disclosed herein is characterized by a base station comprising the following: The base station's processing circuitry generates configuration information for configuring a set of beam indicators, wherein the set of beam indicators includes at least one first beam indicator and at least one second beam indicator, wherein the at least one first beam indicator indicates one or more beams capable of signal transmission and / or signal reception in a serving cell serving a UE, and wherein the at least one second beam indicator indicates one or more candidate beams capable of signal transmission and / or signal reception after a cell handover from the serving cell to a target candidate cell, the target candidate cell being one of one or more candidates participating in the UE's mobility. The base station's transmitter transmits the configuration information.

[0008] Additional benefits and advantages of the disclosed embodiments and different implementations will be apparent from the specification and drawings. Benefits and / or advantages may be obtained individually from the various embodiments and features in the specification and drawings, without the need to provide all embodiments and features to obtain one or more such benefits and / or advantages. Attached Figure Description

[0009] In the following description, exemplary embodiments are described in more detail with reference to the accompanying drawings.

[0010] Figure 1 An exemplary architecture of a 3GPP NR system to which the improved process of this disclosure can be applied is shown;

[0011] Figure 2 This is a schematic diagram illustrating the functional division between the NG Radio Access Network (NG-RAN) and the 5G Core Network (5GC). The improved process of this disclosure can be applied to this functional division.

[0012] Figure 3This is a sequence diagram of a Radio Resource Control (RRC) connection establishment / reconfiguration process that can be implemented using the improved process disclosed herein.

[0013] Figure 4 This is a schematic diagram illustrating use cases for eMBB, mMTC, and URLLC where the improved processes of this disclosure can be applied.

[0014] Figure 5 This is a block diagram illustrating an exemplary 3GPP NR system architecture for non-roaming scenarios.

[0015] Figure 6 The diagram illustrates a split gNB architecture, where the gNB is divided into a central gNB unit and one or more distributed gNB units.

[0016] Figure 7 The diagram illustrates a simplified signaling scheme for handover of lower-level cells within a DU.

[0017] Figure 8 The diagram illustrates several beams and their corresponding SSB indices SSB1-SSB8, as well as how the gNB transmits beams in a beam-scanning manner.

[0018] Figure 9 The illustration shows an exemplary TCI state operation.

[0019] Figure 10 The illustration shows an exemplary MAC-CE message used to activate a subset of the TCI state.

[0020] Figure 11 Another exemplary TCI state operation is illustrated.

[0021] Figure 12 The diagram illustrates an exemplary simplified structure of the UE and gNB.

[0022] Figure 13 The diagram illustrates the structure of a UE according to an exemplary embodiment of the first scheme.

[0023] Figure 14 The diagram illustrates the structure of a gNB according to an exemplary embodiment of the first solution.

[0024] Figure 15 The diagram illustrates a flowchart of UE behavior and base station behavior according to an exemplary implementation of the first scheme.

[0025] Figure 16 The diagram illustrates a flowchart of UE behavior and base station behavior according to an exemplary implementation of the second scheme.

[0026] Figure 17 The illustration shows a first exemplary implementation of the improved beam indicator configuration operation and the improved beam indicator activation operation.

[0027] Figure 18 A second exemplary implementation of the improved beam indicator configuration operation and the improved beam indicator activation operation is illustrated.

[0028] Figure 19 A third exemplary embodiment of the improved beam indicator configuration operation and the improved beam indicator activation operation is illustrated.

[0029] Figure 20 The illustration shows a fourth exemplary implementation of the improved beam indicator configuration and beam indicator activation operations.

[0030] Figure 21 The illustration shows a first exemplary implementation of a MAC-CE message for activating a subset of beam indicators according to the second scheme.

[0031] Figure 22 The illustration shows a second exemplary implementation of a MAC-CE message for activating a subset of beam indicators according to the second scheme.

[0032] Figure 23 The illustration shows a third exemplary implementation of the MAC-CE message for activating a subset of beam indicators according to the second scheme.

[0033] Figure 24 The diagram illustrates a flowchart of UE behavior and base station behavior according to an exemplary implementation of the third scheme.

[0034] Figure 25 The illustration shows a process diagram of an exemplary implementation of the improved beam pointing operation;

[0035] Figure 26 The illustration shows a first exemplary implementation of a beam indicator for reallocating activation after cell handover, and

[0036] Figure 27 A second exemplary implementation for reassigning an active beam indicator after a cell handover is illustrated. Detailed Implementation

[0037] 5G NR System Architecture and Protocol Stack

[0038] 3GPP has been working on the next version of fifth-generation cellular technology (5G), including developing new radio access technologies operating in frequency ranges up to 100 GHz. The first version of the 5G standard was completed at the end of 2017, which allowed for continued 5G NR standard-compliant trials and commercial deployment of smartphones.

[0039] Among other things, the overall system architecture assumes the inclusion of NG-RAN (Next Generation Radio Access Network) for gNBs, thereby providing UEs with NG radio access user plane (SDAP / PDCP / RLC / MAC / PHY) and control plane (RRC) protocol termination. gNBs interconnect with each other via Xn interfaces. gNBs also connect to the 5GC via Next Generation (NG) interfaces, more specifically, via NG-C interfaces to the AMF (Access and Mobility Management Functions) (e.g., specific core entities performing the AMF), and via NG-U interfaces to the UPF (User Plane Functions) (e.g., specific core entities performing the UPF). The NG-RAN architecture in... Figure 1 See the illustration (e.g., 3GPP TS 38.300, v17.2.0, Section 4).

[0040] The NR user plane protocol stack (see, for example, 3GPP TS 38.300, Section 4.4.1) includes PDCP (Packet Data Convergence Protocol, see 3GPP TS 38.300, Section 6.4), RLC (Radio Link Control, see TS 38.300, Section 6.3), and MAC (Media Access Control, see TS 38.300, Section 6.2) sublayers, which terminate in the gNB on the network side. Additionally, a new Access stratum (AS) sublayer (SDAP, Service Data Adaptation Protocol) is introduced above PDCP (see, for example, TS 38.300, Sub-clause 6.5). A control plane protocol stack is also defined for NR (see, for example, TS 38.300, Section 4.4.2). An overview of Layer 2 functions is given in TS 38.300, Sub-clause 6. The functions of the RRC layer are listed in TS 38.300, Sub-clause 7.

[0041] For example, the media access control layer handles logical channel multiplexing and scheduling and scheduling-related functions, including handling different parameter sets.

[0042] The Physical Layer (PHY) is responsible for tasks such as encoding / decoding, PHY HARQ processing, modulation, multi-antenna processing, and mapping signals to appropriate physical time-frequency resources. It also handles the mapping from transport channels to physical channels. The Physical Layer provides services to the MAC Layer in the form of transport channels. A physical channel corresponds to a set of time-frequency resources used for transmission on a specific transport channel, and each transport channel is mapped to a corresponding physical channel. For example, physical channels are PRACH (Physical Random Access Channel), PUSCH (Physical Uplink Shared Channel), and PUCCH (Physical Uplink Control Channel) for uplink, and PDSCH (Physical Downlink Shared Channel), PDCCH (Physical Downlink Control Channel), and PBCH (Physical Broadcast Channel) for downlink.

[0043] NR use cases / deployment scenarios can include enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine-type communication (mMTC), each with different requirements in terms of data rate, latency, and coverage. For example, eMBB is expected to support approximately three times the user experience and peak data rate (20Gbps downlink and 10Gbps uplink) offered by IMT evolution. On the other hand, for URLLC, ultra-low latency (0.5 ms for both UL and DL) and high reliability (1-10 ms within 1 ms) are crucial. -5 This places more stringent requirements on mMTC. Finally, mMTC may preferably require high connection density (1,000,000 devices / km in urban environments). 2 ), extensive coverage in harsh environments, and extremely long-life batteries (15 years) for low-cost devices.

[0044] Therefore, an OFDM parameter set suitable for one use case (e.g., subcarrier spacing, OFDM symbol duration, cyclic prefix (CP) duration, number of symbols per scheduling interval) may not be well suited for another use case. For example, low-latency services may preferably require fewer symbols and / or shorter symbol durations (and therefore larger subcarrier spacings) per scheduling interval (aka TTI) compared to mMTC services. Furthermore, deployment scenarios with large channel delay spreads may preferably require longer CP durations than scenarios with short delay spreads. Subcarrier spacing should be optimized accordingly to maintain similar CP overhead. NR can support more than one value for subcarrier spacing. Accordingly, subcarrier spacings of 15kHz, 30kHz, 60kHz… are currently being considered. Symbol duration T u The subcarrier spacing Δf is obtained through the formula Δf=1 / T uDirectly related. In a manner similar to that in LTE systems, the term "resource element" can be used to represent the smallest resource unit consisting of a subcarrier of one OFDM / SC-FDMA symbol length.

[0045] In the new 5G-NR radio system, for each parameter set and carrier, resource grids for subcarriers and OFDM symbols are defined for both uplink and downlink. Each element in the resource grid is called a resource element and is identified based on its frequency index in the frequency domain and its symbol position in the time domain (see 3GPP TS 38.211, e.g., v17.4.0, e.g., Section 4). For example, downlink and uplink transmissions are organized into frames with a duration of 10 ms, each frame consisting of ten subframes with a duration of 1 ms each. In the 5G NR implementation, the number of consecutive OFDM symbols in each subframe depends on the subcarrier spacing configuration. For example, for a 15 kHz subcarrier spacing, the subframe has 14 OFDM symbols (similar to the LTE-compliant implementation, assuming a normal cyclic prefix). On the other hand, for a 30 kHz subcarrier spacing, the subframe has two slots, each containing 14 OFDM symbols.

[0046] 5G NR Function Division between NG-RAN and 5GC

[0047] Figure 2 The diagram illustrates the functional division between NG-RAN and 5GC. NG-RAN logical nodes are either gNBs or ng-eNBs. 5GC has logical nodes AMF, UPF, and SMF.

[0048] Specifically, gNB and ng-eNB host the following main functions:

[0049] - Functions for radio resource management, such as radio bearer control, radio access control, connection mobility control, and dynamic allocation (scheduling) of resources to the UE in both uplink and downlink.

[0050] - IP header compression, encryption, and data integrity protection;

[0051] - When the route to the AMF cannot be determined based on the information provided by the UE, the AMF is selected when the UE is attached;

[0052] - Routing user plane data to (one or more) UPFs;

[0053] - Routing control plane information to AMF;

[0054] - Connection establishment and release;

[0055] - Scheduling and transmission of paging messages;

[0056] - Scheduling and transmission of system broadcast information (originating from AMF or OAM);

[0057] - Configuration for measurement and measurement reporting for mobility and scheduling;

[0058] - Transport level packet markers in the uplink;

[0059] - Session management;

[0060] - Supports network slicing;

[0061] - QoS flow management and mapping to data radio bearers;

[0062] - Supports UEs in the RRC_INACTIVE state;

[0063] - NAS message distribution functionality;

[0064] - Shared radio access network;

[0065] - Dual connectivity;

[0066] - Close interworking between NR and E-UTRA.

[0067] The Access and Mobility Management Function (AMF) hosts the following key functions:

[0068] - Non-access stratum NAS signaling termination;

[0069] - NAS signaling security;

[0070] - Access layer AS security control;

[0071] - Core network (CN) inter-node signaling for mobility between 3GPP access networks;

[0072] - Idle mode UE reachability (including paging retransmission control and execution);

[0073] - Registration area management;

[0074] - Supports mobility within and between systems;

[0075] - Access authentication;

[0076] - Access authorization, including roaming permission checks;

[0077] - Mobility management controls (subscriptions and policies);

[0078] - Supports network slicing;

[0079] - Session management function SMF selection.

[0080] In addition, the User Plane Function UPF hosts the following main functions:

[0081] - Anchor points for movement within / between RATs (when applicable);

[0082] - External PDU session points interconnected with the data network;

[0083] - Packet routing and forwarding;

[0084] - Group inspection of policy rule enforcement and user plane aspects;

[0085] - Business usage report;

[0086] - Supports uplink classifiers that route service flows to the data network;

[0087] - Supports branching points in multi-homed PDU sessions;

[0088] - QoS processing in the user plane, such as packet filtering, gating, and UL / DL rate implementation;

[0089] - Uplink service verification (SDF to QoS flow mapping);

[0090] - Downlink packet buffering and downlink data notification triggering.

[0091] Finally, the session management function SMF hosts the following main functions:

[0092] - Session management;

[0093] - UE IP address allocation and management;

[0094] - Selection and control of the UP function;

[0095] - Configure service redirection at the User Plane Function (UPF) to route services to the appropriate destination;

[0096] - Policy enforcement and QoS control;

[0097] - Downlink data notification.

[0098] RRC connection establishment and reconfiguration process

[0099] Figure 3The diagram illustrates some interactions between the UE, gNB, and AMF (5GC entity) in the context of the UE transitioning from RRC_IDLE to RRC_CONNECTED for the NAS portion (see 3GPP TS 38.300).

[0100] RRC is a higher-layer signaling (protocol) used for UE and gNB configuration. Specifically, this transition may involve the AMF preparing UE context data (including, for example, PDU session context, security keys, UE radio capabilities, and UE security capabilities) and sending it to the gNB along with an INITIAL CONTEXT SETUP REQUEST. The gNB then activates AS security with the UE, which is performed by the gNB sending a SecurityModeCommand message to the UE and by the UE responding to the gNB with a SecurityModeComplete message. Afterward, the gNB performs reconfiguration to establish Signaling Radio Bearer 2 (SRB2) and (one or more) Data Radio Bearers (DRBs) by sending an RRCReconfiguration message to the UE and receiving an RRCReconfigurationComplete message from the UE in response. For signaling-only connections, the steps related to RRCReconfiguration are skipped because SRB2 and DRBs are not established. Finally, gNB notifies the AMF setup process that it is complete by using INITIAL CONTEXT SETUP RESPONSE.

[0101] Therefore, this disclosure provides an entity for the 5GC (e.g., AMF, SMF, etc.), comprising: a circuit that establishes a next-generation (NG) connection with the gNodeB; and a transmitter that sends an initial context establishment message to the gNodeB via the NG connection to establish a signaling radio bearer between the gNodeB and the user equipment (UE). Specifically, the gNodeB sends RRC signaling containing a resource allocation configuration information element (IE) to the UE via the signaling radio bearer. The UE then performs uplink transmission or downlink reception based on the resource allocation configuration.

[0102] IMT use cases in 2020 and beyond

[0103] Figure 4The diagram illustrates some use cases for 5G NR. In the 3rd Generation Partnership Project New Radio (3GPP NR), three use cases already envisioned by IMT-2020 to support a wide variety of services and applications are being considered. Phase 1 specifications for Enhanced Mobile Broadband (eMBB) have been completed. In addition to further expanding eMBB support, current and future work will involve the standardization of Ultra Reliable and Low Latency Communication (URLLC) and Massive Machine-Type Communication. Figure 4 The illustrations show some examples of envisioned use cases for IMT in 2020 and beyond (see, for example, ITU-R M.20183). Figure 2 ).

[0104] URLLC use cases have stringent requirements for capabilities such as throughput, latency, and availability, and have been envisioned as one of the enablers for future vertical applications, such as wireless control of industrial manufacturing or production processes, telemedicine surgery, distribution automation in smart grids, and transportation security. The ultra-reliability of URLLC will be supported by identifying technologies that meet the requirements set forth in 3GPP TR38.913. For NR URLLC in Release 15, key requirements include a target user plane latency of 0.5 ms for UL (uplink) and 0.5 ms for DL ​​(downlink). The general URLLC requirements for a single packet transmission are a 32-byte packet size, a 1 ms user plane latency, and a BLER (Block Error Rate) of 1E-5.

[0105] From a physical layer perspective, reliability can be improved in a variety of ways. Current approaches to improving reliability involve defining a separate CQI table for URLLC, a more compact DCI format, PDCCH repetition, and more. However, as NR becomes more stable and evolves (regarding NR URLLC key requirements), the scope for achieving ultra-reliability may broaden. Specific use cases for NR URLLC in Rel. 15 include Augmented Reality / Virtual Reality (AR / VR), eHealth, eSafety, and mission-critical applications.

[0106] Furthermore, the technical enhancements targeted by NR URLLC focus on latency and reliability improvements. Enhancements for latency improvement include configurable parameter sets, non-slot-based scheduling with flexible mapping, unlicensed (configurable licensed) uplinks, slot-level repetition for data channels, and downlink preemption. Preemption means stopping a transmission for which resources have already been allocated, and using those resources for another transmission that is subsequently requested but has lower latency / higher priority requirements. Thus, an already licensed transmission is preempted by a subsequent transmission. Preemption can be applied independently of a specific service type. For example, a transmission intended for service type A (URLLC) can be preempted for a transmission intended for service type B (such as eMBB). Technical enhancements for reliability improvement include a dedicated CQI / MCS table for the target BLER of 1E-5.

[0107] The use cases for mMTC (massive machine-type communication) are characterized by a very large number of connected devices typically sending relatively small amounts of non-latency-sensitive data. Devices are required to be low-cost and have very long battery life. From an NR (Radio Frequency Identification) perspective, utilizing a very narrow bandwidth is one possible solution for saving power and achieving long battery life from the UE's (User Equipment) perspective.

[0108] As mentioned above, the range of reliability expected in NR is broad. A key requirement in all cases (especially necessary for URLLC and mMTC) is high or ultra-high reliability. Several mechanisms can be considered to improve reliability from both radio and network perspectives. Generally, there are several key potential aspects that can help improve reliability. These include compact control channel information, data / control channel repetition, and diversity in the frequency, time, and / or spatial domains. These aspects can generally be applied to reliability regardless of the specific communication scenario.

[0109] For NR URLLC, other use cases with more stringent requirements have been identified, such as factory automation, the transportation industry, and power distribution. The more stringent requirement is higher reliability (up to 10). 6 (Level), higher availability, packet size up to 256 bytes, time synchronization in the order of a few μs (where the value can be one or a few μs depending on the frequency range), and short latency of about 0.5 to 1 ms (especially 0.5 ms target user plane latency), depending on the use case.

[0110] In addition, several technical enhancements from a physical layer perspective have been identified for NR URLLC. These include PDCCH (Physical Downlink Control Channel) enhancements related to compact DCI, PDCCH repetition, and increased PDCCH monitoring. Furthermore, UCI (Uplink Control Information) enhancements are associated with enhanced HARQ (Hybrid Automatic Repeat Request) and CSI feedback enhancements. Additionally, PUSCH enhancements related to micro-slot level hopping and repeat / repetition enhancements have also been identified. The term "micro-slot" refers to a transmission time interval (TTI) comprising fewer symbols than a time slot (a time slot consisting of fourteen symbols).

[0111] QoS control

[0112] The 5G QoS (Quality of Service) model is based on QoS flows and supports both QoS flows that require guaranteed flow bit rate (GBR QoS flows) and QoS flows that do not require guaranteed flow bit rate (non-GBR QoS flows). At the NAS level, QoS flows are therefore the finest granularity for QoS differentiation within a PDU session. QoS flows are identified within a PDU session through the QoS Flow ID (QFI) carried in the encapsulation header on the NG-U interface.

[0113] For each UE, 5GC establishes one or more PDU sessions. For each UE, NG-RAN establishes at least one data radio bearer (DRB) along with the PDU session, and subsequently can configure one or more additional DRBs for the QoS flows(s)(s) of that PDU session (depending on when NG-RAN does this), for example, as referenced above. Figure 3 As shown, NG-RAN maps packets belonging to different PDU sessions to different DRBs. NAS-level packet filters in the UE and 5GC associate UL and DL packets with QoS flows, while AS-level mapping rules in the UE and NG-RAN associate UL and DL QoS flows with DRBs.

[0114] Figure 5 The diagram illustrates a 5G NR non-roaming reference architecture (see, for example, 3GPP TS 23.501, e.g., v16.9.0, section 4.2.3, and also v17.5.0 or v18.0.0). Figure 4The application functions (AFs) exemplarily described herein (e.g., external application servers hosting 5G services) interact with the 3GPP core network to provide services, such as supporting application-driven traffic routing, accessing network exposure functions (NEFs), or interacting with policy frameworks used for policy control (e.g., QoS control) (see Policy Control Function, PCF). Based on operator deployment, application functions deemed trusted by the operator may be allowed to interact directly with the relevant network functions. Application functions that the operator does not allow to directly access network functions may interact with the relevant network functions via the NEF using an external exposure framework.

[0115] Figure 5 Other functional units of the 5G architecture are illustrated, namely the Network Slice Selection Function (NSSF), Network Repository Function (NRF), Unified Data Management (UDM), Authentication Server Function (AUSF), Access and Mobility Management Function (AMF), Session Management Function (SMF), and Data Network (DN), such as carrier services, internet access, or third-party services. All or part of the core network functions and application services can be deployed and run on a cloud computing environment.

[0116] Therefore, this disclosure provides an application server (e.g., an AF for a 5G architecture) comprising: a transmitter that sends a request containing QoS requirements of at least one of URLLC, eMBB, and mMTC services to at least one of 5GC functions (e.g., NEF, AMF, SMF, PCF, UPF, etc.) to establish a PDU session including radio bearers between a gNodeB and a UE according to the QoS requirements; and a circuit that uses the established PDU session to perform services.

[0117] Split gNB architecture

[0118] In the 3GPP standard, a gNB can be divided into a gNB-CU (Central Unit) and one or more gNB-DUs (Distributed Units). This is in Figure 6 As shown in the image.

[0119] The gNB-CU is a logical node that provides support for higher layers of the protocol stack, such as SDAP, PDCP, and RRC. Conversely, the gNB-DU is a logical node that provides support for lower layers of the protocol stack, such as RLC, MAC, and the physical layer. Furthermore, note that if the CU is connected to the 4G core network, the SDAP layer will not be present, as a 5G core network is required to support SDAP.

[0120] Therefore, the PHY and MAC layers terminate at gNB-DU, while layer 3 (RRC) terminates at gNB-CU.

[0121] For each gNB, there is a single CU, meaning one gNB-DU connects to only one gNB-CU. Alternatively, for reliability, a gNB-DU can connect to multiple gNB-CUs. One gNB-CU can control multiple gNB-DUs; for example, more than 100 gNB-DUs can connect to one gNB-CU. Each gNB-DU can support one or more cells, so unlike 4G BTS, one gNB can control hundreds of cells. A cell is supported by only one gNB-DU.

[0122] Additionally, note that the interface between the CU and DU is named F1, and according to 3GPP, it should be an open interface. For NG-RAN, the NG and Xn-C interface of a gNB consisting of gNB-CU and gNB-DU terminates in the gNB-CU. For EN-DC, the S1-U and X2-C interface of a gNB consisting of gNB-CU and gNB-DU terminates in the gNB-CU. The gNB-CU and the connected gNB-DU are only visible to other gNBs and the 5GC acting as a gNB.

[0123] The gNB-CU / DU architecture is specified in more detail in, for example, 3GPP TS 38.401 v17.3.0 (e.g., Section 6.1). The F1 interface is specified in more detail in, for example, 3GPP TS 38.473 v17.3.0.

[0124] Layer-1-Layer-2-triggered mobility (LTM)

[0125] When a UE moves from the coverage area of ​​one cell to another, a serving cell change needs to be performed at some point. One possibility is that the serving cell change is triggered by L3 measurements and accomplished via a reconfiguration triggered by RRC signaling, where synchronization is used for changes to the PCell and PSCell, and the release or addition of SCells where applicable. Such a process may involve a complete L2 (and L1) reset, resulting in longer latency, greater overhead, and longer downtime compared to beam switching mobility.

[0126] One of the topics in the ongoing 3GPP Rel.18 work on mobility enhancement is supporting Layer 1-Layer 2 (also known as lower layers) triggered mobility (LTM). The UE is first configured with a set of candidate cells by the RRC (L3). Then, a handover of the UE's serving cell between candidate cells is triggered using L1 or L2 signaling (e.g., MAC CE (and / or possibly DCI)) without requiring RRC reconfiguration. In other words, to facilitate sequential cell handover, cell handover should be prepared in such a way that regardless of which candidate cell becomes the new serving cell, no RRC reconfiguration is required for the UE after the handover. The goal is to reduce the latency, overhead, and downtime of serving cell changes. Intra-DU and intra-CU / inter-DU cell handovers are both within the scope of Rel.18. Figure 6 The diagram illustrates intra-DU handover between two cells with the same gNB-DU and inter-DU handover between two cells with different gNB-DUs.

[0127] Figure 7 This is a simplified exemplary message exchange for lower-level cell handover within a DU, based on the ongoing 3GPP Rel.18 work. Accordingly, it is exemplarily assumed that the gNB-DU controls multiple cells, including the UE's current serving cell. The gNB-DU is connected to the gNB-CU.

[0128] It is evident that cell handover decisions are based on lower-layer (e.g., Layer 1 RSRP) measurements performed at the UE and reported to the gNB-DU. More specifically, the UE measures reference signals from one or more candidate cells from the gNB-DU and reports the results to the gNB-DU. The gNB-DU can use the received measurement results to determine whether to perform LTM on a candidate target cell. A lower-layer cell handover trigger is sent to the UE, allowing the UE to perform a handover from the current cell to another cell of the gNB-DU.

[0129] The benefit of having measurements and reports performed by Layer 1 is low latency.

[0130] Synchronization signal blocks - PSS / SSS, PBCH

[0131] NR has introduced so-called synchronization signal blocks, SS blocks (SSBs), which include the Primary Synchronization Signal (PSS), the Secondary Synchronization Signal (SSS), and the Physical Broadcast Channel (PBCH) (actually PBCH DMRS and PBCH data). UEs can use the PSS and SSS to discover, synchronize, and identify the network. The PBCH carries a minimal amount of system information, including an indication of where to send the remaining broadcast system information.

[0132] In LTE, these three signals, PSS, SSS, and PBCH, are also used, although not as part of a single SSB. The three SSB components are always transmitted together in NR; for example, they have the same period. A given SSB can be repeated within an SS burst set, which can potentially be used for gNB beam scanning transmission. SS burst sets can be limited to specific time periods, such as a 5ms window (half a frame). For initial cell selection, the UE can assume a default SS burst set period of 20ms.

[0133] 5G NR PSS is a Physical Layer Specific Signal used to identify radio frame boundaries and is of type m-sequence. 5G NRSSS is also a Physical Layer Specific Signal used to identify subframe boundaries and is also an m-sequence. PSS / SSS sequences consist of complex values ​​used for each element / sample of the sequence. Information regarding current exemplary 5G implementations of PSS and SSS is available in Sections 7.4.2.2 and 7.4.2.3 of 3GPP TS38.211 v17.4.0, including the corresponding sequence generation and mapping to physical resources.

[0134] The time-frequency structure of the SSB is described in Section 7.4.3.1 of TS 38.211. In such an exemplary 5G implementation, in the time domain, the SSB consists of four OFDM symbols, numbered in ascending order from 0 to 3. The distribution of the PSS, SSS, and PBCH signals within the SSB is defined by Table 7.4.3.1-1.

[0135] In the frequency domain, the SSB consists of 240 consecutive subcarriers, indexed from 0 to 239. The exact subcarriers to be used for each PSS, SSS, and PBCH signal within the SSB are also defined by Table 7.4.3.1-1.

[0136] The gNB informs the UE of the SSB pattern, for example, which SSBs were actually sent and which were not. This can be done, for example, by the gNB sending an SSB bit map that defines the SSB pattern, where each bit of the SSB bit map is associated with an SSB and identifies whether that SSB was sent. The length of the SSB bit map depends on the set of SSBs that can be applied, such as 4, 8, or 64 bits.

[0137] All SSBs can be transmitted using all beams in the system. Alternatively, SSBs can be transmitted in different beams, for example, when SSB beamforming is enabled. In this case, each SSB transmits on a different spatial beam, such as... Figure 8 As illustrated in the diagram, there are 8 SSBs (0-7) that can be transmitted in different beams, each in a different beam direction. Therefore, beam-scanning transmission of the SSBs is achieved; in other words, the scanning transmission of beams (and SSBs) is time-division multiplexed and occurs at different times. Two UEs (UE1 and UE2) will receive different SSBs at different times. Each beam has a beam index, for example, where the beam index corresponds to the index of the SSB transmitted via said beam.

[0138] UEs use SSB in different mechanisms, especially SSB signals (e.g., PSS, SSS, PBCH), such as for serving cell measurements, time / frequency synchronization, etc.

[0139] Beam management

[0140] Beam management (BM) is a collection of Layer 1 (PHY) and Layer 2 (MAC) processes used to establish and retain optimal beam pairs for good connectivity. A beam pair, for example, consists of a transmit beam and a corresponding receive beam in one link direction.

[0141] Before a UE can communicate with the network, it must perform a cell search and selection process and obtain initial cell synchronization and system information. The first step in this process is to obtain frame synchronization, identify the cell identifier, and decode the MIB and SIB1.

[0142] In the case of a multi-antenna system that transmits multiple beams, detecting the beam from the gNB is also part of the initial process (e.g., where the UE typically detects all beams in the search space).

[0143] Beam management can be divided into three main processes:

[0144] Initial beam establishment,

[0145] Beam adjustment (also known as beam tracking and refinement), and

[0146] Beam fault recovery.

[0147] Transmission Configuration Indicator (TCI) Status

[0148] Beam management in 5G Nr has consistently employed a so-called Transmission Configuration Indication (TCI) signaling framework. This means that a specific TCI state can be used by the UE to indicate from the GNB to the UE the beam used for a target channel (such as PDCH, PDCCH) or a target reference signal (such as a Channel State Information Reference Signal (Csi-Rs)). This specific TCI state will be used by the UE to receive the target channel or target signal. The TCI state defines parameters used to configure the quasi-co-location (Qcl) relationship between the source reference signal (Rs) and the target channel or target signal. Therefore, by measuring the source Rs, the UE can set the receive coefficients (e.g., spatial filters) and / or tune the receive antenna for receiving the target channel / signal.

[0149] For example, such as Figure 9 and Figure 11 The TCI state operation, illustrated in a simplified form, includes the following three steps:

[0150] Step 1: The UE is configured by higher-layer signaling (especially RRC signaling) received from the gNB, which, depending on the UE's capabilities, includes a list of up to M TCI states.

[0151] Step 2: The UE receives an Access Control (MAC) Control Element (CE) message from the gNB to activate a subset of pre-configured TCI states, typically up to eight TCI states. Each activated TCI state is mapped by the UE to a code point in the DCI field "Transmission Configuration Indication".

[0152] Step 3: The UE receives the DCI, which indicates one of the code points in the "Transmission Configuration Indication" field of the DCI, and applies the indicated code point to the target channel or target signal.

[0153] Although the TCI state operation described above and below will primarily refer to TCI states applied to downlink target channels or downlink target reference signals, a unified TCI framework has been introduced, particularly in Release 17, allowing TCI states to be applied to multiple channels / signals, including target uplink channels (such as PUSCH or PUCCH) or target uplink reference signals (such as Sounding Reference Signal (SRS)) (see Section 11.1 “Rel-17 Work Item Summary” of 3GPP TR 21.917 V17.0.1).

[0154] TCI status configuration (TCI configuration)

[0155] According to 3GPP TS 38.214, v.17.6.0 (June 2023), the UE can be configured with a list of up to M TCI state configurations within the higher-layer parameter PDSCH-Config via higher-layer signaling (especially RRC signaling) (see example). Figure 9 and Figure 11 (Listed on the left), to decode the PDSCH based on the detected PDCCH with DCI for the UE and a given serving cell. The number M of configured TCI states depends on the UE capability, and for example, there can be up to 128 TCI states for the PDSCH and up to 64 TCI states for the PDCCH. Each TCI-State contains parameters for configuring a quasi-co-address relationship between one or two downlink reference signals and the DM-RS port of the PDSCH, the DM-RS port of the PDCCH, or the CSI-RS port of the CSI-RS resource.

[0156] If the properties of the channel in which symbols are transmitted at one antenna port can be inferred from the properties of the channel in which symbols are transmitted at the other antenna port, then the two antenna ports are called quasi-co-located.

[0157] In 5G NR systems, the Transmission Configuration Indicator (TCI) state is used to establish a quasi-co-located (QCL) connection between the Target Reference Signal (RS) and the Source RS. The antenna port QCL type is defined as follows:

[0158] Type Description

[0159] QCL-A type Doppler frequency shift, Doppler spread, average delay, delay spread

[0160] QCL-B type Doppler frequency shift and Doppler spread

[0161] QCL-C type Doppler frequency shift, average delay

[0162] QCL-D type space Rx parameters

[0163] Configure the TCI state for the PDCCH, PDSCH, and Channel State Information Reference Signal (CSI-RS) to transmit the QCL indication for the corresponding RS. In frequency range 1 (FR1, below 7.125 GHz), QCL type AC is applicable, and in frequency range 2 (FR2, above 24.250 GHz), QCL type AD is applicable. For FR2, QCL type D indicates that the PDCCH / PDSCH / CSI-RS is transmitted with the same spatial filter as the reference signal associated with that TCI. In FR2, the network can indicate a change in the transmit beam of the PDSCH or PDCCH by switching the TCI state.

[0164] As described in Section 6.3.2 of 3GPP TS38.331, v.17.5.0 (June 2023), the IE TCI-State associates one or two DL reference signals with the corresponding quasi-co-address (QCL) type, as follows:

[0165] TCI-State Information Element

[0166]

[0167] Therefore, each TCI state can include a TCI state identifier, a TCI state ID, and a set of RSs or one or more individual RSs for QCL reference. Each RS within a TCI state can be associated with a set of one or more Tx (transmit) and / or Rx (receive) beams. In current 3GPP 5G systems, TCI states are defined for two types of reference signals: SSB (SS block) and CSI-RS (Channel State Information Reference Signal).

[0168] Activation of the TCI state (TCI activation)

[0169] The UE receives activation commands via MAC CE messages, as described in Clause 6.1.3.14 of 3GPP TS 38.321, v17.6.0 (June 23) for UE-specific PDSCH TCI state activation / deactivation, or as described in Clause 6.1.3.47 of 3GPP TS 38.321, v17.6.0 (June 23) for unified TCI state activation / deactivation. Figure 10 As shown in the image.

[0170] Specifically, in such Figure 10In the MAC CE shown, the Serving Cell ID field indicates the ID of the serving cell to which the MAC CE is applied, the DL BWP ID field and the UL BWP IB field indicate the DL or UL bandwidth portion (BWP) to which the MAC CE is applied, respectively, and the P field... i The field indicates whether the i-th TCI code point has multiple TCI states or a single TCI state. The D / U field indicates whether the TCI state ID in the same octet is used for the combined / downlink or uplink TCI state, and the TCI state ID field indicates the identified (to be activated) TCI state.

[0171] Based on the received MAC CE message, the UE activates a subset and / or pairs of up to eight TCI states, one TCI state for the DL channel / signaling, and / or one TCI state for the UL channel / signaling, and maps the activated TCI states to code points in the DCI field "Transmission Configuration Indication". An example mapping / association between activated TCI states and code points is shown in... Figure 9 and Figure 11 The table on the right shows the corresponding subset of activated TCI states.

[0172] For each active TCI state in the subset, the UE needs to perform tracking (see, for example, parameter “tci-StatePDSCH” in TS 38.306, V17.5.0 (July 2023)). This essentially means that the UE performs measurements of the reference signal (e.g., SSB or CSI-RS) associated with the corresponding active TCI state and updates its receive and / or transmit coefficients corresponding to the active TCI state. In other words, the UE prepares the necessary receive and / or transmit parameters corresponding to the active TCI state so that the application time of that beam (or TCI state) is shortened once the beam (or TCI state) is selected by the gNB for transmission / reception. Depending on the measurement and reporting configuration, the UE can report these measurements to the network (e.g., the serving gNB or serving gNB-DU). Based on the received measurements, the network can then, for example, determine the appropriate downlink Tx beam to the UE and / or the appropriate uplink Tx beam from the UE.

[0173] Measurement and reporting can be based, for example, on a CSI reporting framework, which can generally be considered to involve two parts: one for configuration and the other for triggering CSI reporting. Measurement and reporting can be performed on a periodic, semi-periodic, or non-periodic basis.

[0174] Version 17 supports two types of beam management: intra-cell beam management (such as...) Figure 9 (as shown) and inter-cell beam management (such as Figure 11As shown). For intra-cell BM, all active TCI states are in the serving cell of the serving UE (e.g., Figure 9 Cell A in the context has a source RS. For inter-cell BM, the active TCI state can also have a non-serving cell (e.g., cell A) that does not serve the UE. Figure 11 The TCI state associated with the source RS in cell B (e.g., Figure 11 The TCI states are TCI4, TCI5, and TCI6. Therefore, inter-cell BM allows the UE to apply parameters of the TCI state associated with the source RS of the non-serving cell (or in other words, use the beam indicated by the TCI state) to receive or transmit a target channel from or to a non-serving cell without changing the serving cell (performing a cell handover). To support inter-cell BM, the parameter "ServingAdditionalPCIIndex-r17" in the aforementioned IE TCI-State provides the non-serving cell ID to the SSB associated with the configured TCI state. Details can be found in TS 38.331.

[0175] Indication of TCI status (TCI indicator)

[0176] In DCI format 1-1 (section 7.3.1.2.2 of 3GPP TS 38.212 V17.5.0 (March 2023)) and DCI format 1-2 (section 7.3.1.2.3 of 3GPP TS 38.212 V17.5.0 (March 2023)) used for PDSCH scheduling, there is a field called "Transmission Configuration Indication (TCI)," which is used to indicate one of eight active TCI states (if configured) using 3 bits. It is worth noting that DCI format 1-1 or 1-2 used to indicate the TCI can also be sent without scheduling any PDSCH. Procedurally, the UE applies the parameters of the indicated TCI state to the reception of downlink data, for example, as... Figure 10 As shown, when the TCI field has a value of 010, the parameters of TCI state 65 are applied. In other words, the UE uses a beam associated with one or more reference signals of the indicated TCI state to receive the downlink target channel (and / or transmit the uplink target channel). For example, in Figure 9 In the case where TCI state 65 is indicated by DCI with code point 010, the UE applies the parameters of TCI state 65 and transmits (or receives) the target channel using the same spatial filter as the reference signal CSI-RS 1 (of serving cell A), which is associated with TCI 65. Similarly, in Figure 11In this context, TCI state 4 is indicated by DCI with code point 010. The UE applies the parameters of TCI state 4 and transmits (or receives) the target channel using the same spatial filter as the reference signal SSB1 (for non-serving cell B), which is associated with TCI 4.

[0177] Further improvements

[0178] As mentioned above, in Rel.18, to support mobility enhancement, Layer 1-Layer 2 (also known as lower layers) triggered mobility (LTM) has been introduced, where L1 or L2 signaling (such as MAC CE (and / or possibly DCI)) is used to trigger the UE’s serving cell to hand over between candidate cells without requiring RRC reconfiguration.

[0179] To further reduce cell handover latency by performing LTM, it has been agreed that a list of TCI states with source RSs in candidate cells can be configured for the UE by higher-layer signaling (e.g., RRC signaling). Before performing a handover from the current serving cell to the target candidate cell, the MAC CE can activate the configured TCI states with source RSs in the candidate cells, allowing the UE to use the activated TCI states to perform pre-synchronization with the target candidate cell. The cell handover command can indicate a combined or a pair of UL and DL unified TCI states from a subset of activated TCI states for the UE to use in the target cell after performing the handover.

[0180] Typically, the TCI state configured for inter-cell BM can be selected as the TCI state for LTM candidate cells. However, to reduce UE complexity and power consumption when activating the TCI state for inter-cell BM, the TCI state for inter-cell BM is defined only in the same frequency band as the TCI state for intra-cell BM (i.e., BM within the serving cell). Furthermore, under the current mechanism, inter-cell BM can only be configured for adjacent cells with the same gNB-DU.

[0181] On the other hand, the newly introduced mechanism for L1-L2 triggered mobility (LTM) should also allow handover between candidate cells of different gNB-DUs and should not be restricted to the same frequency band, such as the same bandwidth portion (BWP).

[0182] Accordingly, at least for L1-L2 triggered mobility (LTM) between different gNB-DUs, i.e. for inter-DU LTM and for L1-L2 triggered mobility (LTM) between cells with different frequency bands, it is unclear how to configure the TCI state or any other beam indicator for the UE that indicates the beam the UE will use to transmit and / or receive in the candidate cell after a cell handover is performed, because the currently defined TCI state does not include parameters related to such operation.

[0183] Therefore, the inventors identified the possibility of defining improved beam pointing operation to avoid one or more of the aforementioned disadvantages. The present invention relates to different schemes and variations for such improved beam pointing operation.

[0184] Example

[0185] The following describes UEs, base stations, and corresponding processes for new radio access technologies envisioned for 5G mobile communication systems, which meet these requirements; however, they can also be used in previous LTE-based mobile communication systems or future (e.g., 6G) mobile communication systems. Different implementation methods and variations will also be explained. The following disclosure was facilitated by the discussion and findings described above, and may be based, for example, at least in part.

[0186] Generally, it should be noted that many assumptions have been made herein in order to explain the basic principles of this disclosure in a clear, concise, and understandable manner. However, these assumptions are to be understood merely as examples made herein for illustrative purposes and are not necessarily essential to the invention, and therefore should not limit the scope of this disclosure. Those skilled in the art will recognize that the principles set forth in the following disclosure and claims can be applied to different scenarios and in ways not explicitly described herein.

[0187] Furthermore, some terms used below, such as process, entity, and layer, are closely related to those used in LTE / LTE-A systems or current 3GPP 5G standards, even though specific terms used in the context of new radio access technologies for next-generation communication systems have not been fully determined or may eventually change. Therefore, terminology may change in the future without affecting the functionality of the corresponding features and schemes. Thus, those skilled in the art will understand that, due to the lack of updated or ultimately agreed-upon terminology, this scheme and its scope of protection should not be limited to the specific terms used exemplarily herein, but should be understood more broadly based on the functional and conceptual aspects of the schemes explained in this disclosure.

[0188] For example, a mobile station, mobile node, user terminal, or user equipment (UE) is a physical entity (physical node) within a communication network. A node can have several functional entities. A functional entity refers to a software or hardware module that implements and / or provides a predetermined set of functions to the same or another functional entity in the same or another network. A node can have one or more interfaces that allow the node to be attached to a communication facility or medium through which it can communicate. Similarly, a network entity can have logical interfaces that allow functional entities to be attached to a communication facility or medium through which it can communicate with other functional entities or communication nodes.

[0189] The term "base station" or "radio base station" here refers to a physical entity within a communication network. Like a mobile station, a base station can have several functional entities. A functional entity refers to a software or hardware module that implements and / or provides a predetermined set of functions to other functional entities in the same or another node or network. The physical entity performs some control tasks regarding the communication equipment, including one or more of scheduling and configuration. Note that base station functions and communication equipment functions can also be integrated within a single device. For example, a mobile terminal can also implement base station functions for other terminals. The term used in LTE is eNB (or eNodeB), while the current term used for 5G NR is gNB. Furthermore, a base station can also be a gNB in ​​a Non-Terrestrial Network (NTN) NR system.

[0190] Communication between the UE and the base station is usually standardized and can be defined by different layers, such as PHY, MAC, RRC, etc. (see the background discussion above).

[0191] Figure 12 The diagram illustrates a simplified exemplary block diagram of a user equipment (also known as a communication device) and a scheduling device (here, it is exemplarily assumed to be located in a base station, such as an LTE eNB (alternately referred to as an ng-eNB) or a gNB in ​​5G NR). The UE and the eNB / gNB communicate with each other via (wireless) physical channels using transceivers.

[0192] Communication equipment may include transceivers and processing circuitry. A transceiver may further include and / or function as both a receiver and a transmitter. Processing circuitry may be one or more pieces of hardware, such as one or more processors or any LSI. Input / output points (or nodes) exist between the transceiver and processing circuitry, through which the processing circuitry can control the transceiver, i.e., control the receiver and / or transmitter, and exchange received / transmitted data. The transceiver, acting as both a transmitter and receiver, may include an RF (radio frequency) front end, comprising one or more antennas, amplifiers, RF modulators / demodulators, etc. Processing circuitry may perform control tasks, such as controlling the transceiver to transmit user data and control data provided by the processing circuitry and / or to receive user data and control data further processed by the processing circuitry. Processing circuitry may also be responsible for performing other processes, such as determination, decision-making, calculation, and measurement. The transmitter may be responsible for performing the transmission process and other related processes. The receiver may be responsible for performing the reception process and other related processes, such as monitoring the channel.

[0193] The present invention relates to different schemes (and corresponding variations) of improved beam indication operation for layer 1-layer 2 triggered mobility.

[0194] Combining these approaches, an improved UE, an improved base station, and an improved integrated circuit are proposed, which participate individually or together in improved beam indication operation. A mapping method for UE behavior and base station behavior is also provided. The integrated circuit can correspond to both the UE and the base station, and respectively to their behaviors.

[0195] As an overview, according to the first scheme, an improved beam indicator configuration operation is implemented, which either introduces a new type of beam indicator specifically for LTM or extends the existing type of beam indicator (also referred to as a beam indicator for BM), which has been presented in the example above as a beam indicator in the TCI state to define a beam indicator specific to LTM.

[0196] In addition, the second approach provides an improved beam indicator activation operation, which introduces the possibility of unifying the activation operation of LTM beam indicators with the existing activation operation of BM beam indicators.

[0197] The third approach involves an improved beam indicator selection operation and introduces a specific new mechanism for selecting beam indicators for LTM from a subset of beam indicators, which may include beam indicators for LTM and (conventional) beam indicators for BM, as well as parameters for applying the beam indicators indicated by the beam indicators for LTM.

[0198] Finally, the fourth approach introduces a mechanism to directly reuse the actual active subset of beam indicators after cell handover, in order to improve UE process efficiency and potential energy savings.

[0199] It should be noted that each of the first to fourth schemes provides an independent scheme for specific operational steps of existing beam indication operations, such that the first to fourth schemes (especially in combination, but also individually) contribute to providing improved beam indication operations for Layer 1–Layer 2 triggered mobility. In other words, improved beam indication operations of LTM are achieved when at least one of the first to fourth schemes described below or any possible combination of the first to fourth schemes is implemented.

[0200] The following schemes may be based on some or a combination of the different mechanisms described above in the context of the exemplary 3GPP 5G-NR implementation, including, for example, using a TCI operation mechanism to indicate the beam used for the BM (e.g., using information elements of the TCI state), as currently defined in 3GPP. Furthermore, while in the following schemes the TCI state indicator is used as an exemplary implementation of a beam indicator used to indicate to the UE the beam that can be used by the UE, it should be remembered that, alternatively or additionally, the Synchronization Signal Block Identifier (SSB ID) and / or Reference Signal Resource Identifier (RS ID) may be used as the beam indicators described below.

[0201] Option 1 - Beam Indicator Configuration

[0202] Figure 13 A simplified exemplary UE structure is shown according to a basic implementation of the first scheme presented in more detail below. In one example, the UE structure may be based on a combination of Figure 12 The explanation is based on the general UE architecture. Figure 13 The various structural elements of the UE shown can be interconnected with each other, for example, using corresponding input / output nodes (not shown), to exchange control and user data and other signals. Although not shown for illustrative purposes, the UE may include other structural elements.

[0203] As from Figure 13 As is apparent from the following disclosure, the UE may include beam indicator configuration circuitry, which in turn is capable of configuring a set of beam indicators obtained from received configuration information. In this example, as will be apparent from the following disclosure, the configuration information may include at least one second beam indicator that the UE may use for signal transmission and / or signal reception after a cell handover from the serving cell to a target candidate cell, which is one of one or more candidate cells participating in the UE's mobility.

[0204] In this example, as is apparent from the following disclosure, the UE can therefore be configured, by way of example, to use the newly introduced beam indicator type, namely the second beam indicator, which continues the UE’s beam management operations directly after the cell handover indicated by the LTM.

[0205] An exemplary process, as will be disclosed in further detail below, is implemented by a UE comprising the following: The UE's transceiver receives configuration information for configuring a set of beam indicators, wherein the set of beam indicators includes at least one first beam indicator and at least one second beam indicator. The at least one first beam indicator indicates one or more beams capable of being used for signal transmission and / or signal reception in the serving cell serving the UE, and the at least one second beam indicator indicates one or more candidate beams capable of being used for signal transmission and / or signal reception after a cell handover from the serving cell to a target candidate cell, which is one of one or more candidate cells participating in the UE's mobility. The UE's processing circuitry configures the set of beam indicators obtained from the configuration information.

[0206] The UE's processing circuitry can implement more functions than the above-described configuration of the beam indicator set, because it can, for example, further control the transceiver to send or receive control signaling and / or receive or send data by using the configured beam and / or the selected one of the candidate beams.

[0207] The corresponding exemplary method includes the following steps performed by the UE:

[0208] The system receives configuration information for configuring a beam indicator set, wherein the beam indicator set includes at least one first beam indicator and at least one second beam indicator, wherein the at least one first beam indicator indicates one or more beams that can be used for signal transmission and / or signal reception in the serving cell of the UE, and wherein the at least one second beam indicator indicates one or more candidate beams that can be used for signal transmission and / or signal reception after a cell handover from the serving cell to a target candidate cell, the target candidate cell being one of one or more candidate cells participating in the UE's mobility, and configures the beam indicator set obtained from the configuration information.

[0209] exist Figure 15 The left side presents a sequence diagram of exemplary UE behaviors consistent with the UE and UE methods described above.

[0210] Therefore, the improved method described above achieves this objective and overcomes some of the aforementioned drawbacks. Specifically, the improved beam indicator configuration operation allows configuring at least one second beam indicator for the UE. This at least one second beam indicator is a novel beam indicator that indicates a beam that can be used by the UE in the target candidate cell after performing an LTM cell handover. Specifically, at least one second beam indicator can be associated with one or more beams in the target candidate cell, regardless of whether the serving cell and the target candidate cell are cells with the same gNB-DU or different gNB-DUs, and regardless of the frequency domain of the target candidate cell.

[0211] Some exemplary implementations of the improved beam pointing operation also involve improved base stations. Accordingly, the improved beam pointing operation also provides improved base stations participating therein, as will be explained below.

[0212] Figure 14 The illustration shows a simplified exemplary base station structure based on an exemplary implementation of improved beam indication operation, which can be based on a combination of Figure 12 This is implemented using a general base station structure as explained. Figure 14 The various structural elements of the base station shown can be interconnected with each other, for example, using corresponding input / output nodes (not shown), to exchange control and user data and other signals. Although not shown for illustrative purposes, the base station may include other structural elements.

[0213] It is evident from this that the base station includes a beam indicator configuration information generation circuit.

[0214] In this example, as will be apparent from the following disclosure, the base station's processing circuitry can therefore exemplarily generate configuration information for configuring a set of beam indicators, wherein the set of beam indicators includes at least one second beam indicator, wherein the at least one second beam indicator indicates one or more candidate beams capable of being used for signal transmission and / or signal reception after a cell handover from the serving cell to a target candidate cell, the target candidate cell being one of one or more candidates participating in the UE's mobility, etc.

[0215] In this example, as will be apparent from the following disclosure, the base station's transmitter can therefore exemplarily transmit configuration information to the UE, etc.

[0216] An exemplary process, disclosed in further detail below, is implemented by a base station comprising the following: The base station's processing circuitry generates configuration information for configuring a set of beam indicator symbols, wherein the set of beam indicator symbols includes at least one first beam indicator and at least one second beam indicator. The at least one first beam indicator indicates one or more beams capable of being used for signal transmission and / or signal reception in the serving cell of the UE, and the at least one second beam indicator indicates one or more candidate beams capable of being used for signal transmission and / or signal reception after a cell handover from the serving cell to a target candidate cell, which is one of one or more candidates participating in the UE's mobility. The base station's transmitter transmits the configuration information.

[0217] The base station's processing circuitry can implement more functions than the above-described configuration of the beam indicator set, because it can, for example, further control the transceiver to send or receive control signaling and / or receive or send data from the UE, which uses the configured beam and / or a selected one of the candidate beams.

[0218] The corresponding method includes the following steps performed by the base station:

[0219] Configuration information for configuring a set of beam indicators, wherein the set of beam indicators includes at least one first beam indicator and at least one second beam indicator, wherein the at least one first beam indicator indicates one or more beams that can be used for signal transmission and / or signal reception in the serving cell of the UE, and wherein the at least one second beam indicator indicates one or more candidate beams that can be used for signal transmission and / or signal reception after handover from the serving cell to a target candidate cell, the target candidate cell being one of one or more candidates participating in the UE's mobility, and transmission configuration information.

[0220] exist Figure 15 The right side of the diagram illustrates a sequence diagram of exemplary base station behavior according to the aforementioned base station and corresponding method. This sequence diagram illustrates an exemplary simplified implementation of the aforementioned base station method.

[0221] In order to configure at least one beam indicator as a novel beam indicator for LTM, the inventors of the present invention have found two possible solutions: configuring a separate ID space for the beam indicator for LTM from that for BM, as described in Example 1-1 below; or configuring the beam indicator for LTM by reusing the ID space of the beam indicator, as described in Example 1-2 below.

[0222] Example 1-1 - Separate Beam Indicator ID Space

[0223] According to an exemplary implementation of the improved beam indicator configuration operation, at least one first beam indicator is configured separately from at least one second beam indicator.

[0224] In the exemplary implementation of Example 1-1, a candidate TCI state for LTM can be configured for the UE by introducing an IE Candidate-TCI-State, which associates one or more source reference signals from candidate cells for LTM with a candidate-TCI-state ID (identifier). Therefore, in this implementation of Example 1-1, the candidate TCI state ID acts as a second beam indicator by identifying the beam associated with one or more source reference signals of the candidate cell according to the IE Candidate-TCI-State.

[0225] To configure the TCI state for the BM for the UE, the IE TCI-State described above can be reused. In the IE TCI-State, the TCI-State ID acts as the first beam indicator by associating the beam with the source reference signal of the serving cell based on the IE TCI-State identifier.

[0226] For example, the IE Candidate-TCI-State can define the relationship between the candidate-TCI-state ID and one or more source reference signals from candidate cells from LTM as follows:

[0227]

[0228] In this example, the IE Candidate-TCI-State includes additional frequency domain information that is not included in the IE TCI-State (as described above) and allows the configuration of a TCI state for LTM for the UE, which has a frequency band different from the frequency band of the UE's serving cell (e.g., BWP) (so-called "inter-frequency LTM"). In the example above, the frequency band of the candidate cell is indicated by using the parameter ARFCN-ValueNR, which is defined, for example, in 3GPP TS 38.104, V18.2 (June 2023). Alternatively, the frequency band of the candidate cell can also be indicated by using one or more of the following parameters:

[0229] Candidate cell index, which identifies candidate cells in the pre-configured set of candidate cells used for LTM.

[0230] The physical cell ID (PCI) of the candidate cell, or

[0231] If the candidate cell is one of the serving cells in carrier aggregation, the Carrier Indicator Field (CIF) value or ServCellIndex is used.

[0232] In addition to indicating the frequency domain of the candidate cell in the IE Candidate-TCI-State, in another exemplary implementation of the first example, when sending configuration information from the base station to the UE, the frequency domain of the candidate cell can also be individually indicated by sending additional frequency information including one or more of the aforementioned parameters for each Candidate-TCI-State. Figure 15 (In steps S1520 and S1530).

[0233] In Example 1-1 of the first scheme, both the base station and the UE can distinguish at least one first beam indicator and at least one second beam indicator by different identifiers. Specifically, in an exemplary embodiment, the UE and the base station identify the beam indicator as the first beam indicator by using a TCI state ID that identifies the TCI state for BM, and identify the beam indicator as the second beam indicator by using a candidate TCI state ID that identifies the candidate TCI state for LTM.

[0234] In another exemplary embodiment of Example 1-1 of the first scheme, the UE's processing circuitry is configured to list a first list including at least one first beam indicator in the configured beam indicator set, and separately configured to list a second list including at least one second beam indicator in the configured beam indicator set. In other words, the UE's processing circuitry configures separate lists for the beam indicators of the BM (i.e., beam management within the serving cell) and the beam indicators of the LTM (i.e., beam management after LTM cell handover). Figure 17 and Figure 18 The left side of the diagram illustrates an example of such separate lists, showing two lists of configured TCI states. In both diagrams, the upper list of configured TCI states contains the TCI states configured for BM, identified by TCI state IDs (e.g., TCI 1, TCI 2, TCI 3…), serving as an example of a first beam indicator. The lower list of configured TCI states contains the TCI states configured for LTM, identified by candidate TCI state IDs (e.g., candidate TCI 1, candidate TCI 2, candidate TCI 3…), serving as an example of a second beam indicator. Notably, the TCI states for LTM in the second list can include the TCI states of one or more candidate cells from the pre-configured candidate cell set of LTM.

[0235] Example 1-1 of the first scheme has the advantage of allowing the UE and base station to configure the TCI state for BM and the candidate TCI state for LTM independently, respectively. In this way, it is also possible to simply reconfigure either the TCI state for BM or the TCI state for LTM without affecting the other. For example, if the candidate cell set for LTM is reconfigured, the TCI state for LTM can also be reconfigured without potentially affecting the TCI state configured for BM.

[0236] Example 1-2 - Shared Beam Indicator ID Space

[0237] According to another exemplary implementation of the improved beam indicator configuration operation, at least one first beam indicator and at least one second beam indicator are jointly configured.

[0238] In the exemplary implementation of Examples 1-2 of the first scheme, the TCI state for LTM can be configured for the UE using the aforementioned IE TCI-State, allowing joint configuration of the TCI state for BM and the TCI state for LTM using a shared TCI state ID space. Therefore, in this implementation of Examples 1-2, when identifying a beam associated with one or more source reference signals of a candidate cell according to the IE TCI-State, the TCI state ID acts as a second beam indicator. Similarly, when identifying a beam associated with a source reference signal of the serving cell according to the IE TCI-State, the TCI state ID also acts as a first beam indicator. In other words, in the exemplary implementation according to Examples 1-2, both types of TCI states use the same TCI state identifier.

[0239] Since the IE TCI-State does not include a field for indicating frequency domain information, the frequency band of the candidate cell defining the TCI state for LTM can be indirectly provided to the UE through the configuration of the source reference signal, which is associated with the corresponding TCI state for LTM. In alternative or additional implementations, the frequency location of the TCI state for LTM can also be notified to the UE by sending additional frequency information (in...) from the base station to the UE along with the configuration information. Figure 15 (In steps S1520 and S1530). For example, frequency information can be used to indicate the frequency band for the TCI state of LTM by using one or more of the following parameters:

[0240] The ARFCN-ValueNR value, for example, is defined in 3GPP TS 38.104, V18.2 (June 2023).

[0241] The candidate cell index identifies the candidate cell for which a TCI state for LTM is defined within the pre-configured candidate cell set used for LTM.

[0242] It defines the Physical Cell ID (PCI) of candidate cells for the TCI state of LTM, or

[0243] The Carrier Indicator Field (CIF) value, or ServCellIndex, is used when the candidate cell for which the TCI state for LTM is defined is one of the serving cells in carrier aggregation.

[0244] In Examples 1-2 of the first scheme, it is impossible to distinguish at least one first beam indicator and at least one second beam indicator by means of an identifier, because a common identifier is used as both the first and second beam identifiers. Therefore, to distinguish the first and second beam identifiers, according to the exemplary implementation of Examples 1-2, at least one first beam indicator is identified by an index indication in a first value range, and at least one second beam indicator is identified by an index indication in a second value range. In other words, the TCI status identifier, as the first beam identifier corresponding to the TCI status used for BM, can take a value within a first range (e.g., IDs from 1-64), while the second beam identifier corresponding to the TCI status used for LTM can take a value within a second range (e.g., IDs from 65-128) different from the first range. Accordingly, the UE and the base station identify the beam indicator as a first beam indicator by using the value of the TCI state ID in the first range that identifies the TCI state for BM, and identify the beam indicator as a second beam indicator by using the value of the TCI state ID in the second range that identifies the TCI state for LTM.

[0245] In another exemplary embodiment of Examples 1-2 of the first scheme, the UE's processing circuitry configures a common list for listing at least one first beam indicator and at least one second beam indicator contained in the beam indicator set. In other words, the UE's processing circuitry configures a common list for beam indicators used for BM (i.e., beam management within the serving cell) and for LTM (i.e., beam management after LTM cell handover). Figure 19 and Figure 20 The left side of the diagram illustrates an example of such a separate list, showing a public list of configured TCI states. In both diagrams, the public list of configured TCI states includes TCI states configured for BM (e.g., TCI 1, TCI 2, TCI 3…, TCI 64), identified by TCI state IDs with values ​​from 1 to 64, serving as an example of a first beam indicator. Additionally, the public list includes TCI states configured for LTM (e.g., TCI 65, TCI 66, TCI 67…, TCI 128), identified by TCI state IDs with values ​​from 65 to 128, serving as an example of a second beam indicator. It is noteworthy that the TCI states for LTM in the public list can include the TCI states of one or more candidate cells from the pre-configured candidate cell set of the LTM.

[0246] By allowing the same TCI state ID to be used to configure the TCI state for BM and the candidate TCI state for LTM for the UE, no new configuration IE needs to be introduced. Accordingly, Examples 1-2 of the first scheme have the advantage that they allow the UE and the base station to configure the TCI state for BM and the TCI state for LTM for the UE in the same configuration operation. In this way, by utilizing the exemplary implementation of Examples 1-2 of the first scheme, the beam indicator configuration operation can remain simple and the processing workload can be kept small, even when the beam management process is extended to the TCI state for LTM.

[0247] Second option - Beam indicator activation

[0248] As described above, the second approach aims to provide improved beam indicator activation operations, which introduces the possibility of unifying the activation operations of LTM beam indicators with the existing activation operations of BM beam indicators. Most advantageously, the second approach provides a beam indicator activation mechanism for the configured TCI state, configured according to different exemplary implementations of the improved beam indicator configuration operations according to the first approach. However, it should also be noted that the second approach can provide independent improved beam indicator activation operations, even if at least one first beam indicator and at least one second beam indicator are configured in a manner different from that described for the first approach.

[0249] Figure 16 A simplified exemplary sequence diagram illustrating exemplary UE behavior (left) and exemplary base station behavior (right) for a second scheme operating according to improved beam indication is shown. Figure 16 As shown, the beam indicator activation method performed by the base station includes the step (S1610) performed by the base station's processing circuitry: generating activation information for activating one or more beam indicators in a (pre)configured beam indicator set, wherein the one or more beam indicators include at least one second beam indicator to be activated. Thus, the beam indicator set is preferably configured to the UE through one of the exemplary embodiments of the first scheme; however, this is not a necessary condition for performing the beam indicator activation method, as long as the pre-configured beam indicator list includes at least one second beam indicator, which can be used by the UE for transmission or reception after cell handover. After generating the activation information, the beam indicator activation method performed by the base station includes the step (S1620) performed by the base station's transmitter or transceiver: sending the activation information to the UE.

[0250] A beam indicator activation method performed by a UE includes the step (S1630) performed by a receiver or transceiver of the UE: receiving activation information (using activation information (of the UE's transceiver or receiver) for activating one or more beam indicators in a (pre)configured beam indicator set, wherein the one or more beam indicators include at least one second beam indicator to be activated. After receiving the activation information, the beam indicator activation method performed by the UE includes the step (S1640) performed by a processing circuit of the UE: generating an active beam indicator subset including the one or more beam indicators indicated in the activation information. Therefore, the term "generating a beam indicator subset" should be broadly understood to include not only generating the subset from beam indicators specified only in the activation information. Rather, it should include newly generating an active beam indicator subset based on the activation information, updating the existing subset of active beam indicators by including newly activated beam indicators from the activation information into the existing subset, and, if necessary, ultimately deactivating some (but not all) of the previously activated beam indicators.

[0251] In a general exemplary implementation of the second scheme, the activated subset of beam indicators includes at least one beam indicator for BM, particularly at least one TCI state for BM, as a first beam indicator, and at least one beam indicator for LTM, particularly at least one TCI state for LTM, as a second beam indicator, to allow the base station and UE to perform improved beam management for LTM while benefiting from the beam management process already established in the serving cell. However, strictly speaking, to realize the benefits of the improved beam indicator activation operation according to the second scheme, activating the first beam indicator is not necessary, but only at least one of the configured second beam indicators should be activated.

[0252] For each beam indicator included in the subset of active beam indicators, the processing circuitry prepares the beam and / or candidate beam indicated by the active beam indicator for selection for signal transmission and / or signal reception, in order to reduce the processing time required to apply the parameters of the indicated beam after selecting one of the active beams. As described above, this means that for each active TCI state in the subset, the UE needs to perform tracking by performing measurements of the reference signal (e.g., SSB or CSI-RS) associated with the corresponding active beam indicator (e.g., associated with the TCI state) and updating its receive coefficients and / or transmit coefficients corresponding to the active beam indicator (e.g., associated with the TCI state).

[0253] Therefore, the greater the processing complexity and power consumption of the UE, the more active beam indicators (TCI states) there are, especially since active LTM beam indicators require the UE to measure reference signals for candidate cells (different from the serving cell), possibly in a frequency band different from the serving cell. Accordingly, it is conceivable to specify the maximum number of active beam indicators as a UE capability so that the maximum number of active beams is limited depending on the UE capability. Therefore, in a first exemplary embodiment, the maximum number of active beam indicators (indicated by the active TCI state) can be specified individually for each of the intra-cell BM beam indicators (TCI states), inter-cell BM beam indicators (TCI states), and LTM beam indicators (TCI states). Additionally or alternatively, the total number of active beam indicators (TCI states) may also be defined as a UE capability, which includes the sum of beam indicators (TCI states) for intra-cell BMs, beam indicators (TCI states) for inter-cell BMs, and beam indicators (TCI states) for LTM.

[0254] To unify the activation operations of beam indicators (for LTM TCI states) and beam indicators (for BM TCI states), the base station can send activation information to the UE in one or more Media Access Control (MAC) Control Element (CE) messages, causing the UE to receive the activation information in one or more MAC CE messages (and...). Figure 16 (Comparison of steps S1620 and S1630).

[0255] Similar to the improved beam indicator configuration operation of the first scheme, the improved beam indicator activation operation of the second scheme can also be performed independently for the beam indicator (TCI state) of the BM and the beam indicator (TCI state) of the LTM, or in a joint activation operation to activate the configured beam.

[0256] In the first aspect of the improved beam activation operation according to the second scheme, the UE's processing circuitry generates a first subset of beam indicators including all activated first beam indicators, and separately generates a second subset of beam indicators including all activated second beam indicators.

[0257] As described below, in a first alternative embodiment of the first aspect of the second scheme, the processing circuit associates each active first beam indicator contained in the first subset with a code point for selecting the corresponding first beam indicator, and associates each active second beam indicator contained in the second subset with a code point for selecting the corresponding second beam indicator. For example, each active first beam indicator may be mapped by the UE to a code point in a DCI field, such as the DCI field "Transmission Configuration Indication". Similarly, each active second beam indicator may be mapped by the UE to a code point in another DCI field, such as the newly introduced DCI field "Candidate Transmission Configuration Indication". With this implementation, a single DCI can be used to select (indicate) both the first and second beam indicators.

[0258] In an alternative implementation, the same DCI field as the "Transmission Configuration Indication" can be used to map either the active first beam indicator or the active second beam indicator (but not both). The DCI may include a 1-bit field to indicate whether the "Transmission Configuration Indication" field is applied to the active first beam indicator or the active second beam indicator. In this alternative implementation, the DCI is smaller. However, to select both the first and second beam indicators, two DCIs need to be sent.

[0259] For the first aspect of the second scheme, a particularly advantageous option is to implement: the activation information is received by the UE in a first activation message and a second activation message (or sent by the base station), the first activation message specifying at least one first beam indicator to be activated, and the second activation message, separate from the first activation message, specifying at least one second beam indicator to be activated.

[0260] The first aspect of the second approach divides beam indicator activation into separate operations for the first beam indicator and the second beam indicator, which has the particular advantage that the activation of the beam indicator for BM can be performed independently of the activation of the beam indicator for LTM. In this way, one of the subsets of beam indicators for BM activation and the subsets for LTM activation can be modified with new activation information without affecting the other subset.

[0261] Alternatively, in a second exemplary aspect of the improved beam activation operation according to the second scheme, the processing circuit generates a joint subset of beam indicators, which includes all activated first beam indicators and all activated second beam indicators.

[0262] As described below, in an advantageous alternative implementation of the second aspect of the second scheme, the processing circuitry associates each active beam indicator in the joint subset with a code point for selecting the corresponding beam indicator. For example, in an advantageous alternative implementation, each active beam indicator (including a first beam indicator and a second beam indicator) is mapped by the UE to a code point in a DCI field (such as the DCI field "Transmission Configuration Indication").

[0263] For a second aspect of the joint activation operation for the two types of beam indicators, it is also possible to specifically select an implementation: receiving activation information in a single activation message that specifies at least one first beam indicator to be activated and at least one second beam indicator to be activated.

[0264] The second aspect of the second scheme, which uses joint beam indicator activation for the first and second beam indicators, has particular advantages: it reduces the overhead of control information received by the UE because beam indicator activation for both the beam indicator for BM and the beam indicator for LTM can be performed using a single MACCE message. Furthermore, TCI indicators already defined for selecting the TCI state for BM in the serving cell can be reused, as can TCI states for selecting candidate cells in LTM.

[0265] By applying the individual beam indicator activation of the first aspect of the second scheme or the joint beam indicator activation of the second aspect of the second scheme to Example 1-1 (individual beam indicator configuration) or Example 1-2 (shared beam indicator configuration) of the first scheme, there are four possible exemplary implementations, which will be described below as Examples 2-1 to 2-4 of the second scheme.

[0266] Example 2-1 - Individual beam indicator activation for a separate beam indicator ID space

[0267] Figure 17 An exemplary implementation combining individual beam indicator activation with individual beam indicator configuration is shown. As described with respect to Example 1-1, in Figure 17In an exemplary implementation, the UE has been configured with two separate lists of configured TCI states. The upper list of configured TCI states contains TCI states configured for BM, identified by TCI state IDs (e.g., TCI 1, TCI 2, TCI 3…), serving as an example of a first beam indicator. The lower list of configured TCI states contains TCI states configured for LTM, identified by candidate TCI state IDs (e.g., candidate TCI 1, candidate TCI 2, candidate TCI 3…), serving as an example of a second beam indicator. To activate a TCI state from each of the configured TCI state lists, the UE receives separate activation information for the TCI states for BM and for LTM, and accordingly generates a first subset of activated TCI states for BM (e.g.,…). Figure 17 The eight “TCI” states in the upper right list), and independently generate a second subset of active TCI states for LTM (e.g., Figure 17 The eight “candidate TCI” states are listed in the bottom right corner.

[0268] In a preferred embodiment of Example 2-1, the UE receives activation information for activating the TCI state for BM in one or more first MAC CE messages, and the UE receives activation information for activating the TCI state for LTM separately in one or more second MAC CE messages.

[0269] In the first embodiment of Example 2-1, the same design for the MAC CE can be used to activate both the TCI state for BM and the TCI state for LTM separately. For this purpose, a 1-bit flag can be used to indicate whether the MAC CE carries activation information for the TCI state for BM or for LTM. Figure 21 The example document illustrates a newly defined exemplary MAC CE that can be activated for the TCI state of the first implementation of Example 2-1. The exemplary MAC CE of the first implementation of Example 2-1 includes the following fields:

[0270] The field "S", a 1-bit flag, indicates which TCI state in the RRC configuration list the MAC CE applies to. If "S" = 1, it applies to the TCI state of the BM, i.e., the TCI state identified by the TCI state ID. If "S" = 0, it applies to the candidate TCI state identified by the candidate TCI state ID.

[0271] The field "Serving Cell or LTM Candidate Cell ID" indicates the identifier of the serving cell or LTM candidate cell to which MAC CE is applied.

[0272] The “Pi” field, which is related to Figure 10 The "traditional" MAC CE is similarly defined and indicates whether each TCI code point has multiple TCI states or a single TCI state. If the "Pi" field is set to 1, the i-th TCI code point includes both DL TCI and UL TCI states. If the "Pi" field is set to 0, the i-th TCI code point includes only DL / joint TCI states or UL TCI states. The code point mapped to a TCI state is determined by its ordinal position in all TCI state ID fields.

[0273] The “D / U” field, which is related to Figure 10 The "traditional" MAC CE is similarly defined and indicates whether the TCI state ID or candidate TCI state ID in the same octet is used for the joint / downlink or uplink TCI state. If this field is set to 1, the (candidate) TCI state ID in the same octet is used for the joint / downlink. If this field is set to 0, the (candidate) TCI state ID in the same octet is used for the uplink, and...

[0274] The field “(Candidate) TCI State ID” indicates the TCI state identified by the TCI State ID if “Si”=1. If “Si”=0, this field indicates the candidate TCI state identified by the candidate TCI State ID.

[0275] In addition, although not required for the improved TCI state activation operation, the same “DL BWP ID” and “UL BWP ID” as the “traditional” MAC CE can be provided. If S="1", these fields indicate the DL BWP and UL BWP applied to the MAC CE, or if S="0", these two fields can be ignored, along with the reserved bit “R”.

[0276] In an alternative implementation of Example 2-1, different types of MAC CEs can be used to activate the TCI state for BM and the TCI state for LTM. For example, to activate the TCI state for BM, one could use... Figure 10 The existing MAC CE shown is because, in Example 2-1, the activation of the TCI state for BM is independent of the activation of the newly introduced TCI state for LTM. Figure 22 The diagram illustrates an exemplary MAC CE that can activate a newly defined MAC CE for an alternative implementation of the TCI state in Example 2-1. The exemplary MAC CE of the alternative implementation includes the following fields:

[0277] The "Candidate Cell ID" field indicates the identifier of the LTM candidate cell to which the MAC CE is applied. For example, 5 bits are used for this field, but depending on the application scenario, another number of bits is also possible.

[0278] The “Pi” and “D / U” fields are defined for use with “traditional” MAC CE (such as...). Figure 10 (as shown) and the exemplary MAC CE defined for the first implementation of Example 2-1 (such as Figure 21 (as shown)

[0279] The “Candidate TCI State ID” field indicates the candidate TCI state identified by the Candidate TCI State ID.

[0280] In addition, if needed, the exemplary MAC CE of the alternative implementation may also include a reserved bit "R".

[0281] By combining separate beam indicator activation with separate beam indicator configuration, Example 2-1 of the second scheme has the advantage that beam indicator operations for BM and for LTM can be operated independently in terms of configuration and activation, such that, for example, LTM-related beam indicators that are configured and / or activated can be released without affecting beam indicators that are configured and / or activated for BM, and vice versa.

[0282] Example 2-2 - Combined beam indicator activation for individual beam indicator ID spaces

[0283] Figure 18 An exemplary implementation combining joint beam indicator activation with individual beam indicator configurations is shown. As described with respect to Example 1-1, in Figure 18 In an exemplary implementation, the UE has been configured with two separate lists of configured TCI states. The upper list of configured TCI states contains TCI states configured for BM, identified by TCI state IDs (e.g., TCI 1, TCI 2, TCI 3…), serving as an example of a first beam indicator. The lower list of configured TCI states contains TCI states configured for LTM, identified by candidate TCI state IDs (e.g., candidate TCI 1, candidate TCI 2, candidate TCI 3), serving as an example of a second beam indicator. To activate a TCI state from the configuration list, the UE receives joint activation information for the TCI states for BM and LTM, and accordingly generates an activated TCI state for BM (e.g.,…). Figure 18 The list of four “TCI” states in the active TCI state list) and the active TCI state for LTM (e.g., Figure 18 A combined (or common) subset of the four “candidate TCI” states in the list of active TCI states.

[0284] In the first implementation of Example 2-2, activation information for activating the TCI state for BM is received by the UE in one or more joint activation messages, which can specify both the TCI state to be activated for BM and the TCI state to be activated for LTM in a single activation message. Therefore, in the first implementation of Example 2-2, a single MAC CE can be used to send the activation information, which allows the UE to generate... Figure 18 A combined list of active TCI states. For this purpose, an 8-bit field in the MAC CE can be used to indicate whether each active TCI state is for BM or LTM. Figure 23 The diagram illustrates an exemplary MAC CE that can be activated for the TCI state of the first implementation of Example 2-2. The exemplary MAC CE defined for the first implementation includes the following fields:

[0285] The “Si” field is a reference list indicating the TCI state for each code point. If “Si”=1, it refers to the TCI state identified by the TCI state ID. If “Si”=0, it refers to the candidate TCI state identified by the candidate TCI state ID.

[0286] The fields “Serving Cell ID” and “LTM Candidate Cell ID” indicate the identifiers of the serving cell and LTM candidate cell to which MAC CE is applied.

[0287] The fields “DL BWP ID” and “UL BWP ID” indicate the DLBWP and UL BWP to which the TCI status applies, identified by the TCI status ID.

[0288] The “Pi” and “D / U” fields are defined as used in “traditional” MAC CE (e.g., ...). Figure 10 The exemplary MAC CE (as shown) and the first implementation of Example 2-1 are defined as follows: Figure 21 (as shown), and

[0289] The field "(Candidate) TCI State ID" indicates the TCI state identified by the TCI State ID if "Si"=1. If "Si"=0, the field indicates the candidate TCI state identified by the candidate TCI State ID.

[0290] Furthermore, if desired, the exemplary MAC CE of the first implementation of Example 2-2 may also include a reserved bit "R".

[0291] In the second implementation of Example 2-2, as an alternative to the first implementation, similar to Example 2-1, the UE receives activation information for activating the TCI state for BM in one or more first MAC CE messages, and the UE receives activation information for activating the TCI state for LTM separately in one or more second MAC CE messages. Therefore, for example, the two implementations described in Example 2-1 can be used. Activated TCI states and candidate TCI states can be mapped to code points in the DCI, as described in the following two options. In Option 1, the subset of code points indicated by the (candidate) TCI state in the first received MAC CE in chronological order, starting from "000", is activated, and then the remaining code points are activated by the (candidate) TCI state indicated by the second received MAC CE in chronological order. In Option 2, an 8-bit bitmap in the MAC CE is used to indicate which code points(s) the (candidate) TCI state(s) indicated in the MAC CE are mapped to. For example, the bitmap “11100000” indicating the last 3 code points (101, 110, 111) will be modified by the (candidate) TCI state indicated in MAC CE.

[0292] By combining joint beam indicator activation with individual beam indicator configurations, Example 2-2 of the second approach offers the following advantages: beam indicator configurations for BM and LTM can operate independently, while beam indicator activation operations can be unified. Simultaneously, control information overhead can be reduced because a single MAC CE message can be used to activate beam indicators for both BM and LTM. Furthermore, the joint subset allows the use of DCI indicators already defined for the BM beam indicator.

[0293] Example 2-3 - Separate beam indicator activation for sharing beam indicator ID space

[0294] Figure 19 An exemplary implementation combining individual beam indicator activation with a combined beam indicator configuration is shown. As described with respect to Examples 1-2, in Figure 19In an exemplary implementation, the UE has been configured with a public list of configured TCI states. The public list of configured TCI states includes TCI states configured for BM (e.g., TCI 1, TCI 2, TCI 3…, TCI 64), identified by TCI state IDs with values ​​from 1 to 64, as an example of a first beam indicator. Additionally, the public list includes TCI states configured for LTM (e.g., TCI 65, TCI 66, TCI 67…, TCI 128), identified by TCI state IDs with values ​​from 65 to 128, as an example of a second beam indicator. Similar to the exemplary implementation of Example 2-1, in order to activate TCI states from the public list of configured TCI states, in Example 2-3, the UE receives separate activation information for TCI states for BM and TCI states for LTM, and accordingly generates a first subset of activated TCI states for BM (e.g.,…). Figure 19 The eight “TCI” states in the upper right list), and independently generate a second subset of active TCI states for LTM (e.g., Figure 19 The eight “candidate TCI” states are listed in the bottom right section.

[0295] In the preferred embodiments of Examples 2-3, similar to the first embodiment of Example 21, the UE receives activation information for activating the TCI state for BM in one or more first MAC CE messages, and the UE receives activation information for activating the TCI state for LTM separately in one or more second MAC CE messages. Similarly, in the first embodiment of Examples 2-3, referring to... Figure 21 The exemplary MAC CE described with reference to the first embodiment of Example 2-1 can be used to activate the TCI state for BM and to activate the TCI state for LTM. Since the TCI state ID is used as a common identifier for both the TCI state for BM and the TCI state for LTM in Example 2-3, the processing circuitry of the UE in the exemplary embodiment of Example 2-3 distinguishes between the TCI state for BM and the TCI state for LTM based on the value of the TCI state ID. Therefore, if the value of the TCI state ID is in a first range (within... Figure 19 In the example of index 1-64, the corresponding TCI state is identified as the TCI state for BM, and if the value of the TCI state ID is in the second range (in the example of index 1-64), .... Figure 19 Within the examples of indices 65-128, the corresponding TCI state is identified as the TCI state used for LTM. Therefore, due to the use of a shared TCI state ID space in Examples 2-3, information about the type of TCI state is implicitly present in the field "TCI state ID," which replaces the TCI state ID in the first exemplary implementation of Examples 2-3. Figure 21 The MAC CE shown includes the field "(Candidate) TCI State ID". Therefore, it is not necessary to set a 1-bit flag in the MAC CE to distinguish the type of TCI state, and this can be omitted in the first exemplary implementation of Examples 2-3. Figure 21 The “S” field of the MAC CE shown. Accordingly, the MAC CE used in the first embodiment of Examples 2-3 then substantially corresponds to Figure 10 In the traditional MAC CE, only field A, "Serving Cell ID," has been replaced by field "Serving Cell or LTM Candidate Cell ID."

[0296] In the alternative implementations of Examples 2-3, different types of MAC CEs can be used to activate the TCI state for BM and the TCI state for LTM. For example, to activate the TCI state for BM, one could use... Figure 10 The existing MAC CE shown in Example 2-3 is different because the activation of the TCI state for BM is independent of the activation of the newly introduced TCI state for LTM. Then, to activate the TCI state for LTM, for example, one could use... Figure 22 The same MAC CE shown and described for the alternative implementation of Example 2-1.

[0297] By combining individual beam indicator activation with a shared beam indicator configuration, Example 2-3 of the second approach offers the following advantages: beam indicator activation operations for BM and for LTM can be performed independently, allowing, for example, the activation of an LTM-related beam indicator to be released without affecting the activation of the beam indicator for BM in the serving cell, and vice versa. Furthermore, due to the use of a shared beam indicator configuration, it is possible to reuse a traditional MAC CE for the beam indicator activation operation in Example 2-3.

[0298] Example 2-4 - Beam indicator activation for combinations of shared beam indicator ID spaces

[0299] Figure 20 An exemplary implementation combining joint beam indicator activation with joint beam indicator configuration is shown. As described with respect to Examples 1-2, in Figure 20In an exemplary implementation, the UE has been configured with a public list of configured TCI states. The public list of configured TCI states includes TCI states configured for BM (e.g., TCI 1, TCI 2, TCI 3…, TCI 64), identified by TCI state IDs with values ​​from 1 to 64, serving as an example of a first beam indicator. Additionally, the public list includes TCI states configured for LTM (e.g., TCI 65, TCI 66, TCI 67…, TCI 128), identified by TCI state IDs with values ​​from 65 to 128, serving as an example of a second beam indicator. Similar to the exemplary implementation of Example 2-2, to activate a TCI state from the public list of configured TCI states, the UE receives joint activation information for the TCI states for BM and the TCI states for LTM in Example 2-4, and accordingly generates an activation TCI state for BM (e.g.,…). Figure 18 The four “TCI” states in the list of active TCI states) and the active TCI states used for LTM (e.g., Figure 18 A combined (or common) subset of the four “candidate TCI” states in the list of active TCI states.

[0300] In the exemplary implementations of Examples 2-4, activation information for activating the TCI state for BM is received by the UE in one or more joint activation messages, which can specify both the TCI state to be activated for BM and the TCI state to be activated for LTM in a single activation message. For this purpose, in the exemplary implementations of Examples 2-4, a single MACCE can be used to send the activation information, which allows the UE to generate... Figure 20 A combined list of active TCI states. Similarly, in the exemplary implementations of Examples 2-4, refer to... Figure 23 The exemplary MAC CE described with respect to the first embodiment of Example 2-2 can be used to activate the TCI state for BM and to activate the TCI state for LTM.

[0301] Since in Examples 2-4, the TCI State ID is used as a common identifier for both the TCI state for BM and the TCI state for LTM, the processing circuitry of the UE in the exemplary implementation of Examples 2-4 distinguishes between the TCI state for BM and the TCI state for LTM using the same TCI State ID value as described in Examples 2-3. Accordingly, due to the use of a shared TCI State ID space in Examples 2-4, information about the TCI state type is implicitly present in the field "TCI State ID," which replaces the TCI State ID field in the exemplary implementation of Examples 2-4. Figure 23The MAC CE shown includes the field "(Candidate) TCI State ID". Therefore, the MAC CE does not need an 8-bit field to indicate whether each active TCI state is for BM or LTM, and can be omitted in the exemplary implementations of Examples 2-4. Figure 23 The “Si” field of the MAC CE shown. Accordingly, the MAC CE used in the exemplary embodiments of Examples 2-4 substantially corresponds to Figure 10 The traditional MAC CE, with only the "candidate cell ID" field added.

[0302] By combining joint beam indicator activation with shared beam indicator configuration, Example 2-4 of the second scheme offers the following advantages: Beam indicator activation operations for BM and LTM can be unified. This allows for reduced control information overhead, as a single MAC CE message can be used to activate beam indicators for both BM and LTM. Furthermore, the joint subset of activated beam indicators enables the use of DCI indicators already defined for the BM beam indicator.

[0303] Up to this point, for the public lists of configured TCI states in Examples 2-3 and 2-4 (and Example 1-2) and the joint subset of active beam indicators in Examples 2-2 and 2-4, it has been assumed that BM and LTM support the same number of TCI states, e.g., 64+64 configured TCI states and 4+4 active TCI states. In other words, it has been assumed that the ranges of the configured first beam indicator and the configured second beam indicator, as well as the ranges of the active first beam indicator and the active second beam indicator, are the same. However, these figures are given only as examples. Alternatively, the number of TCI states for BM and the number of TCI states for LTM can be divided according to the number of LTM candidate cells. For example, the number of pre-configured TCI states and / or active TCI states for LTM can be configured such that the higher the number, the more LTM candidate cells there are, and vice versa. The number of supported TCI states for BM (for configuration and activation) and / or the number of supported TCI states for LTM (for configuration and activation) can be fixed values ​​defined for all UEs supporting LTM. Alternatively, one or both of these numbers can be configured semi-statically by the network, for example via Operation, Administration and Maintenance (OAM) functions, or dynamically managed via CU / DU inter-signaling, meaning the gNB-CU can determine the allocation of the numbers and notify the connected gNB-DUs accordingly.

[0304] Third option - Beam indicator selection

[0305] As described above, the third approach aims to provide improved beam indicator selection operation, which introduces the possibility of selecting an active beam indicator for LTM while the UE is still connected to the serving cell, so that the UE is ready to use a beam that can be used in the target candidate cell before performing a cell handover from the serving cell to the target candidate cell.

[0306] Most advantageously, the second scheme provides beam indicator selection mechanisms for activating the TCI state, which are activated according to different exemplary implementations of the improved beam indicator activation operation of the second scheme, particularly according to Examples 2-1 to 2-4 of the second scheme. However, it should also be noted that the third scheme can provide independent improved beam indicator selection operation, even if one or more second beam indicators are activated in a manner different from that described for the second scheme.

[0307] Figure 24 A simplified exemplary sequence diagram illustrating exemplary UE behavior (left) and exemplary base station behavior (right) under a third scheme of operation based on improved beam indication is shown. Figure 24 As shown, the beam indicator selection method performed by the base station includes the step (S2410) performed by the base station's processing circuitry: generating selection information for selecting a second beam indicator from the active (second) beam indicator subset. For this purpose, the beam indicator subset is preferably generated by the UE according to one of the exemplary embodiments of the second scheme; however, this is not a necessary condition for performing the beam indicator selection method, as long as the active beam indicator subset or list includes at least one second beam indicator, which can be used by the UE for transmission or reception after cell handover. After generating the selection information, the beam indicator selection method performed by the base station includes the step (S2420) performed using the base station's transceiver or transmitter: sending the selection information to the UE.

[0308] The beam indicator selection method performed by the UE includes the step (S2430) performed by the UE's transceiver or receiver: receiving selection information for selecting a second beam indicator among active beam indicators. After receiving the selection information, the beam indicator selection method performed by the UE includes the step (S2440) performed by the UE's processing circuitry: preparing to use a selected second beam indicator indicated by the selection information for signal transmission and / or signal reception after a cell handover from the serving cell to the target candidate cell. For this purpose, preparation for using a selected beam indicator includes, for example, the processing circuitry adjusting the settings of the UE's hardware components to prepare for the use of the beam indicated by the selected beam indicator directly in the target candidate cell after the cell handover. For example, the UE's processing circuitry may tune the UE's antenna or adjust the beam pattern to be used for the beam indicated by the selected beam indicator.

[0309] Selection information for choosing one of the second beam indicators can be sent from the base station to the UE via DCI (i.e., received by the UE in step S2430), or in other words, by including the selection information in the DCI message. For example, the DCI field "Transmission Configuration Indication (TCI)" previously described in the TCI Status Indication (TCI Indication) section can be reused to indicate a code point mapped to the selected beam indicator in the list of active beam indicators.

[0310] When the UE performs a separate beam activation operation, as in Examples 2-1 and 2-3 of the second scheme, and the UE has stored a first subset consisting only of active first beam indicators (e.g., TCI states for BM) and a second subset consisting only of active second beam indicators (e.g., TCI states for LTM), the DCI message may, for example, include a 1-bit field indicating which subset (or list) the selection information included in the DCI is applied to. For example, if the 1-bit field is set to "1", this might mean that the selection information included in the DCI is applied to the list of active second beam indicators (e.g., TCI states for LTM), such that the selection information included in the DCI (e.g., in the DCI field "Transmission Configuration Indicator (TCI)") selects code points from the list of active second beam indicators. Similarly, if a 1-bit field is set to "0", this could mean that the selection information included in the DCI is applied to the list of active first beam indicators, such that the selection information included in the DCI (e.g., in the DCI field "Transmission Configuration Indicator (TCI)") selects code points from the list of active first beam indicators.

[0311] Alternatively, one of the first beam indicators (e.g., the TCI state for the BM) can be selected using only a DCI (or DCI message) including the DCI field "Transmission Configuration Indication (TCI)", similar to the description of the TCI state selection operation for the TCI state for the BM in the preceding TCI State Indication (TCI Indication) section. The selection information for selecting one of the second beam indicators can then be transmitted from the base station to the UE, for example, by using a MAC CE message, thus avoiding the need to include a 1-bit field in the DCI message or redefine the DCI field to introduce the option to select the active second beam indicator.

[0312] When the beam indicator activation operation uses a combined beam activation operation, as in Examples 2-2 and 2-4 of the second scheme, and the UE has stored a combined subset of beam indicators that includes all active first beam indicators and all active second beam indicators, the DCI message can be the same as described previously in the TCI state indication (TCI indication) section. However, if it becomes beneficial to introduce more than 8 active TCI states, for example, to combine TCI states for LTM used for multiple candidate cells and / or frequency bands, the number of bits allocated to the DCI field "Transmission Configuration Indication (TCI)" can be increased.

[0313] Figure 25 A process diagram illustrating an exemplary implementation of the improved beam selection process according to the third scheme is shown. Figure 25 In the example shown, the UE is initially served by serving cell A. This means the UE connects to the gNB-DU supporting cell A and receives control information from the gNB-DU supporting cell A, such as the configuration information, activation information, and selection information mentioned above. As long as the UE is served by cell A, the UE performs beam management in serving cell A by using the beam indicated in the TCI state for BM to signal transmission and reception, because the TCI state for BM includes TCI states for intra-cell beam management and inter-cell beam management.

[0314] Then, as Figure 25 As shown by the arrow at the bottom of the timeline, the UE receives cell handover trigger information from serving cell A. This information indicates that cell B is the target candidate cell for LTM cell handover, and cell B becomes the new serving cell for the UE after the LTM cell handover. Therefore, after the LTM cell handover, the previous target candidate cell B is the new serving cell for the UE. This means that after the LTM cell handover, the UE connects to the gNB-DU supporting cell B and receives control information from it, such as the configuration information, activation information, and selection information mentioned above. The gNB-DU supporting cell B can be the same as or different from the gNB-DU supporting cell A.

[0315] like Figure 25 As shown, in step S2510, the UE is configured by receiving RRC signaling with a set of beam indicator symbols, including TCI states for BM (in cell A), particularly intra-cell BM and inter-cell BM, and TCI states for LTM. TCI state operation is preferably performed according to one of the exemplary embodiments of the first scheme. In step S2520, the UE receives one or more MAC CEs for activating at least one of the TCI states for BM and one of the TCI states for LTM, and activates the corresponding TCI states accordingly. Next, the UE may receive selection information indicating the selection of one of the TCI states to be activated for BM (step S2530), and / or selection information indicating the selection of one of the TCI states to be activated for LTM (step S2550). If a TCI state for BM is indicated, the UE applies the indicated TCI state when it is in the current serving cell (step S2540). This means that after the processing time has elapsed, the UE will directly use the BM beam indicated by the selected TCI state to transmit and / or receive signals in the serving cell, which is necessary for the UE to prepare its hardware to use the indicated beam.

[0316] If a TCI state for LTM is selected, the operation differs, and the UE applies the indicated TCI state for LTM only after the UE switches to the target candidate cell associated with the selected TCI state for LTM (step S2560). In other words, even after the processing time for preparing to use the beam has elapsed, the UE does not use the beam indicated by the selected TCI state for LTM to transmit and / or receive signals in the serving cell, but only after the cell switches to the candidate cell associated with the selected TCI state for LTM. Therefore, the selected TCI state for LTM is applied only when the candidate cell associated with the selected TCI state for LTM becomes the new serving cell after the LTM cell handover. This means that the UE only uses the beam indicated in the TCI state for LTM to transmit and / or receive signals in the new serving cell (corresponding to the previous target candidate cell), not before the LTM cell handover.

[0317] It is worth noting that, in Figure 25In the exemplary illustration, the selection information (S2530) including the TCI indication for BM is received by the UE (or sent by the base station) before the TCI selection information (S2550) including the LTM indication. This should be understood as an example, not a limitation. Specifically, the above description also applies to scenarios where the TCI indication for LTM is received (sent) earlier than the TCI indication for BM, or scenarios where the TCI indication and the TCI indication for BM are received (sent) simultaneously. Furthermore, the above description also applies to scenarios where multiple TCI indications (S2530) for BM (or multiple TCI indications for LTM) are received before cell handover.

[0318] In a preferred embodiment of the third scheme, the transceiver of the UE receives cell handover trigger information from the serving cell. The cell handover trigger information indicates that one of the candidate cells in a pre-configured set of candidate cells is the target for cell handover among a plurality of pre-configured candidate cells. The UE's processing circuit controls the cell handover from the serving cell to the target candidate cell according to the cell handover trigger information. After the cell handover, the transceiver uses a selected second beam indicator to transmit and / or receive signals in the target candidate cell.

[0319] Therefore, as a first option, the selection information is provided before the cell handover trigger information, i.e., while the UE is still in its original serving cell. This allows the necessary processing for using the beam indicated in the selected second beam to be completed while the UE is in its original serving cell (see [link to relevant documentation]). Figure 25 The processing time in the process allows the beam to be ready to be used once a cell handover is indicated, which can further reduce the delay of L1 / L2 triggered mobility procedures.

[0320] As a second option, the selection information can be received as part of the cell handover trigger information, or as a third option, the selection information can be received after the cell handover trigger information. While these schemes still require a delay due to processing time to prepare the beam for use, they still reduce the delay in completing the necessary processing (see...). Figure 25 The processing time (in the process) is because the selected beam indicator has already been activated in the original serving cell, so that the beam indicated by the selected beam indicator has been pre-synchronized.

[0321] Fourth Option - Beam Indication After Cell Handover

[0322] After the UE has performed an LTE cell handover, the target candidate cell becomes the new serving cell. Because the new serving cell can be supported by a different gNB-DU than the original cell, and for the original cell, the first beam indicator (e.g., the TCI state for BM) and the second beam indicator (e.g., the TCI state for LTM) have already been activated, it is unclear how to handle the previously activated beam indicators after the cell handover. However, even if the original cell and the new serving cell are associated with the same gNB-DU, from the UE's perspective, it remains unclear how the UE should act based on the previously activated beam indicators. A fourth scheme for improved beam indicator operation provides several examples that offer different solutions to this problem.

[0323] Example 4-1 – Do not retain beam indicator

[0324] According to Example 4-1 of the fourth scheme, after an LTM cell handover has been performed, the UE's processing circuitry deactivates all first beam indicators except for the second beam indicator currently used for signal transmission and / or signal reception in the target candidate cell, and all second beam indicators included in the subset of activated beam indicators.

[0325] For example, the UE's processing circuitry deactivates all active TCI states for BM and active TCI states for LTM, except for the TCI state for LTM, which were activated in the original serving cell before the cell handover. The TCI state for LTM was selected before the cell handover and indicates the beam used in the new serving cell (i.e., the previous target candidate cell) after the LTM cell handover. Additionally, the UE waits to receive new activation information from the gNB-DU supporting the new serving cell, such as beam indicators sent in one or more MAC CE messages, for activating the new serving cell.

[0326] By releasing or deactivating all beam indicators except the one indicating the currently used beam, the capability requirements on the UE can be reduced, because the UE does not need to continue tracking beam indicators that were already active in the old serving cell after a cell handover.

[0327] Example 4-2 - Retain the second beam indicator associated with the target cell

[0328] According to Example 4-2 of the fourth scheme, after LTM cell handover has been performed, the UE's processing circuitry deactivates all first beam indicators and all second beam indicators included in the active beam indicator subset, which can be used for signal transmission and / or signal reception in another candidate cell different from the target candidate cell.

[0329] For example, in addition to the active TCI states for LTM associated with the new serving cell (i.e., the previous target candidate cell) after LTM cell handover, the UE's processing circuitry deactivates all active TCI states for BM and active TCI states for LTM that were already active in the original serving cell before the cell handover. In other words, after cell handover, the UE's processing circuitry can retain only the active TCI states for LTM associated with the new serving cell, because these TCI states can be used to perform beam management in the new serving cell, especially intra-cell BM. The retained active TCI states can, for example, remain active until the UE receives new activation information from the gNB-DU supporting the new serving cell, for example, sent in one or more MACCE messages, for activating the beam indicator for the new serving cell.

[0330] In the scheme of Example 4-2, the capability requirements for the UE are slightly increased compared to the scheme of Example 4-1. However, because the UE retains all active beam indicators associated with the new serving cell, the UE can perform beam management directly in the new serving cell after cell handover without waiting for the new beam indicator to activate. Therefore, by implementing Example 4-2, the latency of LTM operation is further reduced.

[0331] Example 4-3 - Retaining a second beam indicator not associated with the target cell

[0332] According to Example 4-3 of the fourth scheme, after performing LTM cell handover, the UE's processing circuitry deactivates all first beam indicators and all second beam indicators included in the subset of activated beam indicators, except for the second beam indicator currently used for signal transmission and / or signal reception in the target candidate cell and the second beam indicator associated with candidate cells other than the target candidate cell.

[0333] For example, the UE's processing circuitry deactivates all active TCI states for BM and active TCI states for LTM associated with the new serving cell, except for the TCI states for LTM selected before the cell handover and indicating the beams to be used in the new serving cell (i.e., the previous target candidate cell) after the LTM cell handover. In other words, after the cell handover, the UE's processing circuitry may retain only the active TCI states for LTM associated with candidate cells other than the new serving cell, because these TCI states can be used to perform subsequent cell handovers from the new serving cell to the new target candidate cell. The retained active TCI states may, for example, remain active until the UE receives new activation information from the gNB-DU supporting the new serving cell, for example, sent in one or more MAC CE messages, for activating the beam indicator for the new serving cell.

[0334] In the scheme of Example 4-3, the capability requirements for the UE may be slightly increased compared to the scheme of Example 4-1. However, since the UE retains all active beam indicators associated with candidate cells other than the new serving cell, the beam indicator can be directly indicated to the UE after the first cell handover for subsequent LTM cell handovers in the new serving cell, without waiting for a new beam indicator to be activated. Therefore, by implementing Example 4-3, the latency of LTM operation is further reduced.

[0335] Example 4-4 - Retaining the Second Beam Indicator

[0336] Example 4-4 provides a solution that combines the advantages of the solutions in Embodiments 4-2 and 4-3. Specifically, according to Example 4-4, the UE's processing circuitry deactivates all first beam indicators included in the subset of activated beam indicators after LTM cell handover.

[0337] For example, the UE's processing circuitry deactivates all active TCI states of the BM (Brightness Management Center) and retains all active TCI states of the LTM (Light Module). Because the processing circuitry retains all active LTM TCI states, beam management can be performed directly in the new serving cell after a cell handover using the LTM TCI states associated with the new serving cell, particularly intra-cell BM, or subsequent cell handovers can be performed from the new serving cell to a new candidate target cell using the LTM TCI states associated with candidate cells other than the target candidate cell, without waiting for new TCI states to activate. The retained active TCI states can, for example, remain active until the UE receives new activation information from the gNB-DU supporting the new serving cell, such as a beam indicator sent in one or more MAC CE messages, for activating the new serving cell.

[0338] In the solution of Example 4-4, the capability requirements for the UE may be slightly increased compared to the solutions of Examples 4-1, 4-2, and 4-3. However, because the UE retains all active beam indicators used for LTM, the UE can perform beam management and / or indicate subsequent LTM cell handovers directly in the new serving cell after the first cell handover using beam indicators, without waiting for new beam indicators to activate. Therefore, by implementing Example 4-4, the latency of LTM operation is further reduced.

[0339] Example 4-5 - Retain the first beam indicator

[0340] Example 4-5 provides a scheme that can be implemented not only as an alternative to the schemes described in Examples 4-1 to 4-4, but also in combination with one of the schemes described in Examples 4-1 to 4-4.

[0341] According to Examples 4-5, the UE's processing circuitry retains the first beam indicator in a subset of the active beam indicators. Alternatively, at least one of the retained first beam indicators can be selected for use in transmitting signals to and / or receiving signals from the serving cell, which becomes a candidate for UE mobility participation after LTM cell handover.

[0342] For example, after an LTM cell handover, the UE's processing circuitry retains all TCI states used for the BM (meaning the BM in the original serving cell). However, as... Figure 26 and Figure 27 As exemplarily illustrated, the TCI for the BM configured and activated by the original serving cell can include TCI states for intra-cell BMs, such as TCI states TCI 1 and TCI 3 in cell A, which have a source reference signal in cell A, and TCI states for inter-cell BMs, such as TCI states TCI 4 and TCI 6 in cell A, which have a source reference signal in cell B. Now, after an LTM cell handover from cell A to cell B, once cell B becomes the new serving cell, the TCI states of the intra-cell BMs in cell A become the TCI states of the inter-cell BMs in cell B, because these states have a source reference signal in cell A, such as... Figure 26 and Figure 27 The TCI states are TCI 1 and TCI 3. Similarly, after an LTM cell handover from cell A to cell B, once cell B becomes the new serving cell, the TCI state of the inter-cell BM of cell A with the source reference signal in cell B will change to the TCI state of the intra-cell BM in cell B. As with Examples 4-1 to 4-4, after an LTM cell handover, the retained active TCI state for the BM can remain active, for example, until the UE receives new activation information from the gNB-DU supporting the new serving cell, for example, sent in one or more MAC CE messages, for activating the beam indicator of the new serving cell.

[0343] Therefore, Example 4-5 allows for the continued use of the first beam indicator to perform inter-cell BM and intra-cell BM immediately after LTM cell handover, without waiting for a new beam indicator to be activated.

[0344] In a first alternative implementation of Examples 4-5, after cell handover, the association between each active beam indicator and the code point used to select the corresponding first beam indicator is maintained. This is, for example, in... Figure 26As shown, the mapping of the active TCI state for the BM to a specific code point remains unchanged, while the type of the TCI state for the BM is exchanged between intra-cell BMs and inter-cell BMs, and vice versa, as described above. Therefore, in this example cell A, the TCI state of the intra-cell BM is mapped to code points 000 and 001, while the TCI state of the inter-cell BM is mapped to code points 010 and 011. After an LTM cell handover in cell B, the TCI state of the intra-cell BM is mapped to code points 010 and 011, while the TCI state of the inter-cell BM is mapped to code points 000 and 001. This has the advantage that the UE does not need to provide further processing after an LTM cell handover.

[0345] In a second alternative implementation of Examples 4-5, after cell handover, the association between each active beam indicator and the code point used to select the corresponding beam indicator is changed. This is, for example, in... Figure 27 The diagram illustrates how the mapping of the active TCI state for the BM to a specific code point changes based on the TCI state type for the BM in the new serving cell B. Therefore, in this example, within cells A and B, the intra-cell TCI state of the BM is mapped to code points 000 and 001, while the inter-cell TCI state of the BM is mapped to code points 010 and 011. The advantage of this approach is that the order of the internal and external TCI state types can be maintained after an LTM cell handover.

[0346] Implementations 4-1 to 4-5 of the fourth scheme have now been described. Therefore, it should be noted that for each of Examples 4-2, 4-3, 4-4, and 4-5, in cases where the target gNB-DU supporting the new serving cell after LTM cell handover is different from the source gNB-DU supporting the original serving cell, the source gNB-DU, which had configured the UE's active TCI states before the LTM cell handover, should notify the target gNB-DU which active TCI states the UE retains after the LTM cell handover. Since no direct interface is defined between the source gNB-DU and the target gNB-DU in 5GNR, the source gNB-DU should communicate this information to the target gNB-DU via the gNB-CU to which both gNB-DUs are connected (see, for example...). Figure 6 (The separate gNB architecture).

[0347] Whether a particular example from Examples 4-1 to 4-5, or a combination thereof, is supported can depend on UE capabilities. For example, before performing LTM operation, a UE can generate a capability report that includes information about its ability to support retained active beam indicators after an LTM cell handover. The UE can send the capability report to the network (e.g., serving gNB-CU or serving gNB-DU), and the network can then follow the mode reported by the UE. In cases where the UE report supports various combinations of Examples 4-1 to 4-5, the network should select a mode that allows support for the highest number of retained TCI states reported by the UE after an LTM cell handover. Alternatively, depending on one of Examples 4-1 to 4-5, or a combination thereof, a defined mode for retained TCI states may exist that needs to be applied by all LTM-enabled UEs.

[0348] Other aspects

[0349] According to a first aspect, a user equipment (UE) is provided, comprising: a transceiver receiving configuration information for configuring a beam indicator set, wherein the beam indicator set includes at least one first beam indicator and at least one second beam indicator, wherein the at least one first beam indicator indicates one or more beams in a serving cell capable of serving the UE for signal transmission and / or signal reception, and wherein the at least one second beam indicator indicates one or more candidate beams capable of signal transmission and / or signal reception after a cell handover from the serving cell to a target candidate cell, the target candidate cell being one of one or more candidate cells participating in the mobility of the UE; and processing circuitry of the UE configuring the beam indicator set obtained from the configuration information.

[0350] According to the second aspect provided in addition to the first aspect, at least one first beam indicator and at least one second beam indicator are configured separately. In an alternative embodiment of the second aspect, the at least one first beam indicator and the at least one second beam indicator are identified by different identifiers, and / or the processing circuitry configures a first list and separately configures a second list, the first list listing at least one first beam indicator included in the beam indicator set, and the second list listing at least one second beam indicator included in the beam indicator set.

[0351] According to a third aspect provided in addition to the first aspect, at least one first beam indicator and at least one second beam indicator are jointly configured. In an alternative embodiment of the third aspect, the at least one first beam indicator is identified by being indicated by an index in a first value range, and the at least one second beam indicator is identified by being indicated by an index in a second value range, and / or the processing circuitry configures a common list for storing the at least one first beam indicator and the at least one second beam indicator included in the beam indicator set.

[0352] According to a fourth aspect provided in addition to one of the first to third aspects, the transceiver receives activation information for activating one or more beam indicators in a configuration beam indicator set, wherein the one or more beam indicators include at least one second beam indicator to be activated. Processing circuitry generates an activated subset of beam indicators including the one or more beam indicators indicated in the activation information, and prepares beams and candidate beams to be selected for signal transmission and / or signal reception, indicated by the activated beam indicators. In an alternative implementation of the fourth aspect, if the activation information is received in one or more Media Access Control (MAC) Control Element (CE) messages, and / or if the one or more beam indicators further include at least one first beam indicator to be activated, then the activation information is received in a first activation message and a second activation message separate from the first activation message, the first activation message specifying at least one first beam indicator to be activated, the second activation message specifying at least one second beam indicator to be activated, and / or if the one or more beam indicators further include at least one first beam indicator to be activated, then the activation information is received in a single activation message specifying at least one first beam indicator to be activated and at least one second beam indicator to be activated.

[0353] According to the fifth aspect provided in addition to the fourth aspect, the processing circuit generates a first subset of beam indicators and separately generates a second subset of beam indicators, the first subset including all active first beam indicators and the second subset including all active second beam indicators. In an alternative embodiment of the fifth aspect, the processing circuit associates each active first beam indicator included in the first subset with a code point for selecting the corresponding first beam indicator, and separately associates each active second beam indicator included in the second subset with a code point for selecting the corresponding second beam indicator.

[0354] According to the sixth aspect provided in addition to the fourth aspect, the processing circuit generates a joint subset of beam indicators, the joint subset including all active first beam indicators and all active second beam indicators. In an alternative embodiment of the sixth aspect, the processing circuit associates each active beam indicator included in the joint subset with a code point for selecting the corresponding beam indicator.

[0355] According to a seventh aspect provided in addition to one of the fourth to sixth aspects, the transceiver selection information is used to select a second beam indicator among the active beam indicators. After a cell handover from the serving cell to the target candidate cell, the processing circuitry prepares to use the selected second beam indicator indicated by the selection information for signal transmission and / or signal reception. In an alternative embodiment of the seventh aspect, the selection information is received in a downlink control information (DCI) message, or the selection information is received in one or more media access control (MAC) control element (CE) messages.

[0356] According to the eighth aspect, in addition to the seventh aspect, the transceiver receives cell handover triggering information from the serving cell, the cell handover triggering information indicating a candidate cell from a pre-configured set of candidate cells as the target for cell handover among a plurality of pre-configured candidate cells. The processing circuitry controls the cell handover from the serving cell to the target candidate cell based on the cell handover triggering information. The transceiver uses a selected second beam indicator for signal transmission and / or signal reception in the target candidate cell. In an optional embodiment of the eighth aspect, the transceiver receives the selection information before the cell handover triggering information, or the transceiver receives the selection information as part of the cell handover triggering information, or the transceiver receives the selection information after the cell handover triggering information.

[0357] According to a ninth aspect provided in addition to any of the fourth to eighth aspects, after a handover from the serving cell to the target candidate cell, the processing circuitry deactivates all second beam indicators included in the activated beam indicator subset that can be used for signal transmission and / or signal reception in another candidate cell different from the target candidate cell. As an alternative or addition to the ninth aspect, after a cell handover from the serving cell to the target candidate cell, the processing circuitry deactivates all second beam indicators included in the activated beam indicator subset that can be used for signal transmission and / or signal reception in the target candidate cell, except for the second beam indicators currently used for signal transmission and / or signal reception in the target candidate cell.

[0358] According to a tenth aspect provided in addition to one of the fourth to ninth aspects, the processing circuit deactivates all first beam indicators included in the activated beam indicator subset after switching from the serving cell to the target candidate cell.

[0359] According to the eleventh aspect, in addition to any one of the fourth to ninth aspects, after a cell handover from the serving cell to the target candidate cell, at least one second beam indicator included in the active subset of beam indicators can be selected in the target candidate cell for signal transmission and / or signal reception, the target candidate cell serving the UE after the cell handover. As an alternative or addition to the eleventh aspect, if at least one of the first beam indicators is included in the active subset of beam indicators, after a cell handover from the serving cell to the target candidate cell, at least one first beam indicator included in the active subset of beam indicators can be selected for transmitting signals to and / or receiving signals from the serving cell, the serving cell becoming a candidate for UE mobility after the cell handover.

[0360] In an alternative embodiment of the eleventh aspect, after the cell handover, the association between each active beam indicator and the code point used to select the corresponding beam indicator is changed. In an alternative embodiment of the eleventh aspect, after the cell handover, the association between each active beam indicator and the code point used to select the corresponding beam indicator is changed.

[0361] According to the twelfth aspect provided in addition to one of the first to eleventh aspects, each beam indicator is a Transmission Configuration Indicator (TCI) status identifier, a Synchronization Signal Block Identifier (SSB ID), and / or a Reference Signal Resource Identifier (RS ID).

[0362] According to a thirteenth aspect, a base station is provided, comprising: a processing circuit of the base station for generating configuration information for configuring a set of beam indicators, wherein the set of beam indicators includes at least one first beam indicator and at least one second beam indicator, wherein the at least one first beam indicator indicates one or more beams capable of signal transmission and / or signal reception in a serving cell serving a UE, and wherein the at least one second beam indicator indicates one or more candidate beams capable of signal transmission and / or signal reception after a cell handover from the serving cell to a target candidate cell, the target candidate cell being one of one or more candidates participating in the mobility of the UE; and a transmitter of the base station for transmitting the configuration information.

[0363] According to the fourteenth aspect, a method is provided that includes the following steps performed by a user equipment (UE):

[0364] Receive configuration information for configuring the beam indicator set.

[0365] The beam indicator set includes at least one first beam indicator and at least one second beam indicator.

[0366] Wherein, the at least one first beam indicator indicates one or more beams capable of signal transmission and / or signal reception in the serving cell serving the UE, and

[0367] Wherein, at least one second beam indicator indicates one or more candidate beams, which can be used for signal transmission and / or signal reception after a cell handover from the serving cell to a target candidate cell, the target candidate cell being one of one or more candidates participating in the UE's mobility; and

[0368] Configure the set of beam indicators obtained from the configuration information.

[0369] According to the fifteenth aspect, an integrated circuit (which can be deployed in a communication system, particularly in a user equipment (UE)) is provided. This integrated circuit controls the processing of the communication device during operation, the processing including the steps of the method according to the fourteenth aspect.

[0370] According to the sixteenth aspect, a method is provided that includes the following steps performed by a base station (BS):

[0371] Generate configuration information for configuring the beam indicator set.

[0372] The beam indicator set includes at least one first beam indicator and at least one second beam indicator.

[0373] Wherein, the at least one first beam indicator indicates one or more beams capable of signal transmission and / or signal reception in the serving cell serving the UE, and

[0374] Wherein, the at least one second beam indicator indicates one or more candidate beams that can be used for signal transmission and / or signal reception after a cell handover from the serving cell to a target candidate cell, the target candidate cell being one of one or more candidates participating in the mobility of the UE; and

[0375] Send the configuration information.

[0376] According to the seventeenth aspect, an integrated circuit (which can be deployed in a communication system, particularly in a base station) is provided. The integrated circuit controls a process for communication equipment, the process including the steps of the method according to the sixteenth aspect.

[0377] Other variations including hardware and software implementations of this disclosure

[0378] This disclosure can be implemented in software, hardware, or software cooperating with hardware. Each functional block used in the description of each of the above embodiments can be implemented in part or in whole by an LSI such as an integrated circuit, and each process described in each embodiment can be controlled in part or in whole by the same LSI or a combination of LSIs. An LSI can be formed as a separate chip, or it can be formed as a single chip to include part or all of the functional blocks. An LSI can include data inputs and outputs coupled thereto. Depending on the level of integration, the LSI herein can be referred to as an IC (integrated circuit), a system LSI, a super LSI, or an ultra-LSI. However, the technology for implementing an integrated circuit is not limited to LSIs and can be implemented using dedicated circuitry, general-purpose processors, or special-purpose processors. Furthermore, an FPGA (Field-Programmable Gate Array) that can be programmed after the LSI is manufactured, or a reconfigurable processor that can reconfigure the connections and settings of the circuit cells arranged within the LSI, can be used. This disclosure can be implemented as digital or analog processing. If future integrated circuit technology replaces the LSI as a result of advancements in semiconductor technology or other derivative technologies, the functional blocks can be integrated using future integrated circuit technology. Biotechnology can also be applied.

[0379] This disclosure can be implemented by any kind of device, apparatus or system having communication functions, referred to as a communication device.

[0380] Communication devices may include transceivers and processing / control circuitry. A transceiver may include and / or function as both a receiver and a transmitter. As a transmitter and receiver, a transceiver may include an RF (radio frequency) module and one or more antennas; the RF module may include amplifiers, RF modulators / demodulators, etc.

[0381] Some non-limiting examples of such communication devices include telephones (e.g., cellular phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, netbooks), cameras (e.g., digital still / video cameras), digital players (digital audio / video players), wearable devices (e.g., wearable cameras, smartwatches, tracking devices), game consoles, digital book readers, telemedicine / telehealth (remote health and medical) devices, and vehicles that provide communication capabilities (e.g., cars, airplanes, ships), and various combinations thereof.

[0382] Communication devices are not limited to portable or mobile devices, but may also include any kind of non-portable or fixed devices, equipment or systems, such as smart home devices (e.g., appliances, lighting, smart meters, control panels), vending machines, and any other “things” in a network of the Internet of Things (IoT).

[0383] Communication can include exchanging data through, for example, cellular systems, wireless LAN systems, satellite systems, and various combinations thereof.

[0384] The communication device may include devices such as controllers or sensors coupled to a communication device that performs the communication functions described in this disclosure. For example, the communication device may include a controller or sensor that generates control signals or data signals used by the communication device performing the communication functions of the communication device.

[0385] Communication devices may also include infrastructure such as base stations, access points, and any other devices, equipment, or systems that communicate with or control such devices as those in the non-limiting examples above.

[0386] (Control signal)

[0387] In this disclosure, the downlink control signals (information) associated with this disclosure may be signals (information) transmitted via the physical layer PDCCH, or signals (information) transmitted via a higher-layer MAC control element (CE) or RRC. Downlink control signals may be predefined signals (information).

[0388] The uplink control signals (information) related to this disclosure may be signals (information) transmitted via the physical layer PUCCH, or signals (information) transmitted via a higher-layer MAC CE or RRC. Furthermore, the uplink control signals may be predefined signals (information). The uplink control signals may be replaced by uplink control information (UCI), first-stage side uplink control information (SCI), or second-stage SCI.

[0389] (Base station)

[0390] In this disclosure, a base station can be, for example, a Transmitter Receiver Point (TRP), a trunking head, an access point, a Remote Radio Header (RRH), an eNodeB (eNB), a gNodeB (gNB), a Base Station (BS), a Base Transceiver Station (BTS), a Base Station Unit, or a gateway. Furthermore, in sidelink communication, a terminal may be used instead of a base station. A base station can be a relay device that relays communication between higher nodes and terminals. A base station can also be a roadside unit.

[0391] (Uplink / Downlink / Sidelink)

[0392] This disclosure can be applied to any of the uplink, downlink, and sidelink.

[0393] This disclosure can be applied to, for example, uplink channels (such as PUSCH, PUCCH and PRACH), downlink channels (such as PDSCH, PDCCH and PBCH), and sidelink channels (such as physical sidelink shared channel (PSSCH), physical sidelink control channel (PSCCH) and physical sidelink broadcast channel (PSBCH)).

[0394] PDCCH, PDSCH, PUSCH, and PUCCH are examples of downlink control channel, downlink data channel, uplink data channel, and uplink control channel, respectively. PSCCH and PSSCH are examples of sidelink control channel and sidelink data channel, respectively. PBCH and PSBCH are examples of broadcast channels, and PRACH is an example of a random access channel.

[0395] (Data channel / Control channel)

[0396] This disclosure can be applied to either a data channel or a control channel. The channels in this disclosure can be replaced by data channels including PDSCH, PUSCH, and PSSCH and / or control channels including PDCCH, PUCCH, PBCH, PSCCH, and PSBCH.

[0397] (Reference signal)

[0398] In this disclosure, the reference signal is a signal known to both the base station and the mobile station, and each reference signal may be referred to as a reference signal (RS) or sometimes as a pilot signal. The reference signal may be any one of DMRS, Channel State Information Reference Signal (CSI-RS), Tracking Reference Signal (TRS), Phase Tracking Reference Signal (PTRS), Cell Specific Reference Signal (CRS), and Sounding Reference Signal (SRS).

[0399] (Time interval)

[0400] In this disclosure, a time resource element is not limited to one or a combination of a time slot and a symbol, and can be a time resource element such as a frame, superframe, subframe, time slot, time slot sub-time slot, micro-time slot, or a time resource element such as a symbol, Orthogonal Frequency Division Multiplexing (OFDM) symbol, Single Carrier-Frequency Division Multiplexing Access (SC-FDMA) symbol, or other time resource elements. The number of symbols included in a time slot is not limited to any number of symbols exemplified in the above embodiments, but can be other numbers of symbols.

[0401] (frequency band)

[0402] This disclosure can be applied to either licensed or unlicensed frequency bands.

[0403] (communication)

[0404] This disclosure can be applied to any of the following: communication between a base station and a terminal (Uu link communication), communication between terminals (side link communication), and vehicle to everything (V2X) communication. The channels in this disclosure can be replaced by PSCCH, PSSCH, Physical Side Link Feedback Channel (PSFCH), PSBCH, PDCCH, PUCCH, PDSCH, PUSCH, and PBCH.

[0405] Furthermore, this disclosure can be applied to any of terrestrial networks using satellites or High Altitude PseudoSatellites (HAPS), or networks other than terrestrial networks (NTN: non-terrestrial networks). Additionally, this disclosure can be applied to networks with large cell sizes, and to terrestrial networks with large delays compared to symbol lengths or time slot lengths, such as ultra-wideband transmission networks.

[0406] (Antenna port)

[0407] An antenna port refers to a logical antenna (antenna array) formed by one or more physical antennas. That is, an antenna port does not necessarily refer to a single physical antenna; sometimes it refers to an array of antennas, such as multiple antennas. For example, instead of defining how many physical antennas form an antenna port, an antenna port is defined as the smallest unit through which a terminal can transmit a reference signal. An antenna port can also be defined as the smallest unit used for weighted multiplication in precoding vectors.

[0408] Furthermore, various embodiments can also be implemented using software modules executed by a processor or directly in the hardware. Combinations of software modules and hardware implementations are also possible. Software modules can be stored on any type of computer-readable storage medium, such as RAM, EPROM, EEPROM, flash memory, registers, hard disks, CD-ROMs, DVDs, etc. It should also be noted that various features of different embodiments can individually or in any combination form the subject matter of another embodiment.

[0409] Those skilled in the art will understand that various changes and / or modifications can be made to this disclosure as illustrated in the specific embodiments. Therefore, this embodiment is to be considered illustrative rather than restrictive in all respects.

Claims

1. A user equipment (UE), comprising: Transceiver, the transceiver: Receive configuration information for configuring the beam indicator set. The beam indicator set includes at least one first beam indicator and at least one second beam indicator. Wherein, the at least one first beam indicator indicates one or more beams capable of being used for signal transmission and / or signal reception in the serving cell serving the UE, and Wherein, the at least one second beam indicator indicates one or more candidate beams that can be used for signal transmission and / or signal reception after a cell handover from the serving cell to a target candidate cell, the target candidate cell being one of one or more candidates participating in the UE's mobility; and Processing circuit, the processing circuit: Configure the set of beam indicators obtained from the configuration information.

2. The UE according to claim 1, wherein, The at least one first beam indicator and the at least one second beam indicator are configured separately. Optionally, the at least one first beam indicator and the at least one second beam indicator are identified by different identifiers; and / or Optionally, the processing circuit configures a first list and separately configures a second list, the first list listing at least one first beam indicator included in the beam indicator set, and the second list listing at least one second beam indicator included in the beam indicator set.

3. The UE according to claim 1, wherein, The at least one first beam indicator and the at least one second beam indicator are configured together. Optionally, the at least one first beam indicator is identified by an index in a first value range, and the at least one second beam indicator is identified by an index in a second value range; and / or Optionally, the processing circuitry is configured with a common list for storing the at least one first beam indicator and the at least one second beam indicator included in the beam indicator set.

4. The UE according to any one of claims 1 to 3, wherein, The transceiver: Receive activation information for activating one or more beam indicators in the configured beam indicator set, wherein the one or more beam indicators include at least one second beam indicator to be activated; and The processing circuit: Generate an active subset of beam indicators, including the one or more beam indicators indicated in the activation information; and Prepare the beam and candidate beams to be selected for signal transmission and / or signal reception, as indicated by the activated beam indicator; Optionally, the activation information is received in one or more Media Access Control (MAC) control element (CE) messages; Optionally, where, in the case that the one or more beam indicators further include at least one first beam indicator to be activated, the activation information is received in a first activation message and a second activation message separate from the first activation message, the first activation message specifying at least one first beam indicator to be activated, and the second activation message specifying at least one second beam indicator to be activated; and / or Optionally, where, if the one or more beam indicators further include at least one first beam indicator to be activated, the activation information is received in a single activation message specifying at least one first beam indicator to be activated and at least one second beam indicator to be activated.

5. The UE according to claim 4, wherein, The processing circuit: A first subset of beam indicators is generated, and a second subset of beam indicators is generated separately. The first subset includes all active first beam indicators, and the second subset includes all active second beam indicators. Optionally, the processing circuit associates each active first beam indicator included in the first subset with a code point for selecting the corresponding first beam indicator, and separately associates each active second beam indicator included in the second subset with a code point for selecting the corresponding second beam indicator.

6. The UE according to claim 4, wherein, The processing circuit generates a joint subset of beam indicators, the joint subset including all active first beam indicators and all active second beam indicators. Optionally, the processing circuitry associates each active beam indicator in the joint subset with a code point for selecting the corresponding beam indicator.

7. The UE according to any one of claims 4 to 6, wherein, The transceiver: Receive selection information, the selection information being used to select a second beam indicator from the active beam indicators; and The processing circuit: After a cell handover from the serving cell to the target candidate cell, preparations are made to use a selected second beam indicator indicated by the selection information for signal transmission and / or signal reception. Optionally, the selection information is received in a downlink control information (DCI) message; or Optionally, the selection information is received in one or more Media Access Control (MAC) control element (CE) messages.

8. The UE according to claim 7, wherein, The transceiver receives cell handover triggering information from the serving cell, the cell handover triggering information indicating one candidate cell from a pre-configured set of candidate cells as the target for cell handover among multiple pre-configured candidate cells, and The processing circuit controls the cell handover from the serving cell to the target candidate cell based on the cell handover trigger information; and The transceiver will select a second beam indicator for signal transmission and / or signal reception in the target candidate cell; Optionally, the transceiver receives the selection information before the cell handover trigger information; Wherein, the transceiver receives the selection information as part of the cell handover trigger information; or The transceiver receives the selection information after the cell handover trigger information.

9. The UE according to any one of claims 4 to 8, wherein, Following a cell handover from the serving cell to the target candidate cell, the processing circuit deactivates all second beam indicators included in the activated beam indicator subset that are capable of signal transmission and / or signal reception in another candidate cell different from the target candidate cell, and / or Wherein, after a cell handover from the serving cell to the target candidate cell, the processing circuit deactivates all second beam indicators included in the activated beam indicator subset that can be used for signal transmission and / or signal reception in the target candidate cell, except for the second beam indicator currently used for signal transmission and / or signal reception in the target candidate cell.

10. The UE according to any one of claims 4 to 9, wherein, After a cell handover from the serving cell to the target candidate cell, the processing circuit deactivates all first beam indicators included in the activated beam indicator subset.

11. The UE according to any one of claims 4 to 9, wherein, Following a cell handover from the serving cell to the target candidate cell, at least one second beam indicator, included in the subset of activated beam indicators, can be selected in the target candidate cell for signal transmission and / or signal reception, the target candidate cell serving the UE after the cell handover, and / or When at least one of the first beam indicators is included in the active subset of beam indicators, after a cell handover from the serving cell to the target candidate cell, the at least one first beam indicator included in the active subset of beam indicators can be selected for sending signals to and / or receiving signals from the serving cell, which becomes a candidate for participating in the mobility of the UE after the cell handover. Optionally, after the cell handover, the association between each activated beam indicator and the code point used to select the corresponding first beam indicator is maintained, or Optionally, after the cell handover, the association between each active beam indicator and the code point used to select the corresponding beam indicator is changed.

12. The UE according to any one of claims 1 to 11, wherein, Each beam indicator is a Transmission Configuration Indicator (TCI) Status Identifier, a Synchronization Signal Block Identifier (SSB ID), and / or a Reference Signal Resource Identifier (RS ID).

13. A base station, comprising: Processing circuit, the processing circuit: Generate configuration information for configuring the beam indicator set. The beam indicator set includes at least one first beam indicator and at least one second beam indicator. Wherein, the at least one first beam indicator indicates one or more beams that can be used for signal transmission and / or signal reception in the serving cell of the serving UE, and Wherein, the at least one second beam indicator indicates one or more candidate beams that can be used for signal transmission and / or signal reception after a cell handover from the serving cell to a target candidate cell, the target candidate cell being one of one or more candidates participating in the UE's mobility; and Transmitter: Send the configuration information.

14. A method comprising the following steps performed by a user equipment (UE): Receive configuration information for configuring the beam indicator set. in, The beam indicator set includes at least one first beam indicator and at least one second beam indicator. Wherein, the at least one first beam indicator indicates one or more beams capable of signal transmission and / or signal reception in the serving cell serving the UE, and Wherein, the at least one second beam indicator indicates one or more candidate beams that can be used for signal transmission and / or signal reception after a cell handover from the serving cell to a target candidate cell, the target candidate cell being one of one or more candidates participating in the mobility of the UE; and Configure the set of beam indicators obtained from the configuration information.

15. An integrated circuit for controlling a process of a user equipment (UE), the process comprising: Receive configuration information for configuring the beam indicator set. The beam indicator set includes at least one first beam indicator and at least one second beam indicator. Wherein, the at least one first beam indicator indicates one or more beams capable of signal transmission and / or signal reception in the serving cell serving the UE, and Wherein, the at least one second beam indicator indicates one or more candidate beams capable of being used for signal transmission and / or signal reception after a cell handover from the serving cell to a target candidate cell, the target candidate cell being one of one or more candidates participating in the mobility of the UE; and Configure the set of beam indicators obtained from the configuration information.

16. A method comprising the following steps performed by a base station (BS): Generate configuration information for configuring the beam indicator set. in, The beam indicator set includes at least one first beam indicator and at least one second beam indicator. Wherein, the at least one first beam indicator indicates one or more beams that can be used for signal transmission and / or signal reception in the serving cell of the serving UE, and Wherein, the at least one second beam indicator indicates one or more candidate beams capable of being used for signal transmission and / or signal reception after a cell handover from the serving cell to a target candidate cell, the target candidate cell being one of one or more candidates participating in the mobility of the UE; and Send the configuration information.

17. An integrated circuit for controlling a process of a base station, the process comprising: Generate configuration information for configuring the beam indicator set. The beam indicator set includes at least one first beam indicator and at least one second beam indicator. Wherein, the at least one first beam indicator indicates one or more beams that can be used for signal transmission and / or signal reception in the serving cell of the serving UE, and Wherein, the at least one second beam indicator indicates one or more candidate beams capable of being used for signal transmission and / or signal reception after a cell handover from the serving cell to a target candidate cell, the target candidate cell being one of one or more candidates participating in the UE's mobility; and Send the configuration information.

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