TCI and pathloss reference signal pre-configuration for candidate cells

Abstract

In one embodiment, an apparatus can be a UE configured to receive, from a network node, a handover indication for the UE to handover from being served by a first cell to being served by a second cell. The apparatus can also be configured to receive a transmit configuration indication (TCI) status indication, the transmit configuration indication (TCI) status indication indicating a TCI status for use by the UE with the second cell, wherein a first time period between the handover indication and the TCI status indication is based on a relationship of the TCI status and one or more reference signals measured by the UE prior to receiving the handover indication. The apparatus can also be configured to communicate with the network node via the second cell and using the TCI state.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit and priority of U.S. Provisional Application Serial No. 63 / 381,548, filed on October 28, 2022, entitled "TCI AND PATH LOSS REFERENCE SIGNAL PRE - CONFIGURATION FOR CANDIDATE CELLS", and U.S. Non - Provisional Patent Application Serial No. 18 / 464,802, filed on September 11, 2023, entitled "TCI AND PATH LOSS REFERENCE SIGNAL PRE - CONFIGURATION FOR CANDIDATE CELLS", the entire disclosures of which are hereby incorporated by reference in their entireties. Technical Field

[0003] The present disclosure generally relates to communication systems and, more particularly, to layer 1 and / or layer 2 mediated cell mobility. Background Art

[0004] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasting. A typical wireless communication system may employ a multiple access technology that is capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple access technologies include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single - Carrier Frequency Division Multiple Access (SC - FDMA) systems, and Time - Division Synchronous Code Division Multiple Access (TD - SCDMA) systems.

[0005] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at the urban, national, regional, or even global level. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of the continuous mobile broadband evolution promulgated by the 3rd Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., related to the Internet of Things (IoT)), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine - type communication (mMTC), and ultra - reliable low - latency communication (URLLC). Some aspects of 5G NR may be based on the 4G Long - Term Evolution (LTE) standard. Further improvements to 5G NR technology are needed. In addition, these improvements may also be applicable to other multiple access technologies and telecommunication standards that employ these technologies. Summary of the Invention

[0006] A simplified summary of one or more aspects is presented below to provide a basic understanding of these aspects. This Summary of the Invention is not an extensive overview of all contemplated aspects. The Summary of the Invention neither identifies key or critical elements of all aspects nor describes the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0007] In one aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be configured to receive, from a network node, a handover indication for a UE to hand over from being served by a first cell to being served by a second cell. The apparatus may also be configured to receive a transmit configuration indication (TCI) state indication that indicates a TCI state for use by the UE with the second cell, wherein a first time period between the handover indication and the TCI state indication is based on a relationship between the TCI state and one or more reference signals measured by the UE before receiving the handover indication. The apparatus may also be configured to communicate with the network node via the second cell and using the TCI state.

[0008] In one aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be configured to indicate, via a handover indication, that a UE hands over from being served by a first cell to being served by a second cell. The apparatus may also be configured to indicate, via a TCI state indication, a TCI state for use by the UE with the second cell, wherein a first time period between the handover indication and the TCI state indication is based on a relationship between the TCI state and one or more reference signals measured by the UE before the handover to the second cell. The apparatus may also be configured to communicate with the UE via the second cell and using the TCI state.

[0009] To achieve the foregoing and related purposes, one or more aspects include the features described in full below and particularly pointed out in the claims. The following description and the drawings set forth in detail some illustrative features of one or more aspects. However, these features are indicative of only some of the various ways in which the principles of the various aspects may be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network.

[0011] Figure 2A is a diagram illustrating an example of a first frame in accordance with various aspects of the present disclosure.

[0012] Figure 2BIs a diagram illustrating an example of a downlink (DL) channel within a subframe according to various aspects of the present disclosure.

[0013] Figure 2C Is a diagram illustrating an example of a second frame according to various aspects of the present disclosure.

[0014] Figure 2D Is a diagram illustrating an example of an uplink (UL) channel within a subframe according to various aspects of the present disclosure.

[0015] Figure 3 Is a diagram illustrating an example of a base station and a user equipment (UE) in an access network.

[0016] Figure 4A Is a diagram illustrating aspects of a timeline associated with the activation of a TCI state.

[0017] Figure 4B Is a diagram illustrating aspects of a timeline associated with the activation of a TCI state.

[0018] Figure 5 Is a diagram illustrating that a UE experiences a mobility event (e.g., a handover or a handoff) due to moving from a first location to a second location according to some aspects of the present disclosure.

[0019] Figure 6 Is a call flow diagram illustrating a wireless communication method for reducing latency during a handover of a UE from being served by a first cell to being served by a second cell in a cell group associated with a network node according to some aspects of the present disclosure.

[0020] Figure 7 Is a call flow diagram illustrating a wireless communication method for reducing latency during a handover of a UE from being served by a first cell to being served by a second cell in a cell group associated with a network node according to some aspects of the present disclosure.

[0021] Figure 8 Is a diagram illustrating the mapping of a reference signal to a TCI state associated with different cells.

[0022] Figure 9 Is a flowchart of a wireless communication method.

[0023] Figure 10 Is a flowchart of a wireless communication method.

[0024] Figure 11 Is a flowchart of a wireless communication method.

[0025] Figure 12 Is a flowchart of a wireless communication method.

[0026] Figure 13A diagram illustrating examples of hardware implementations for a device.

[0027] Figure 14 A diagram illustrating examples of hardware implementations for a network entity. Detailed Description

[0028] In some aspects of wireless communication (e.g., 5G NR), a UE in motion may experience multiple inter-cell handovers during which the UE served by a first cell switches to being served by a second cell. In some aspects, the UE may be configured to communicate with multiple candidate cells such that if the communication quality with the current serving cell (e.g., the primary cell or PCell) is below a threshold quality, the UE may switch to being served by a second cell (e.g., a secondary cell or SCell in a set of candidate SCells) among the multiple cells. In some aspects, during a handover operation, the UE may perform additional beam training and / or management operations associated with a set of TCI states selected from a pool of TCI states associated with the second cell. In some aspects, the additional beam training and / or management operations may be based on a reference signal received after an indication for activating the set of TCI states. Thus, communication via the second cell may involve additional latency associated with waiting for the next instance of the reference signal associated with the activated TCI state. The additional latency may be associated with the periodicity of the associated reference signal (e.g., 20 ms for a Synchronization Signal Block (SSB)). A method and apparatus for reducing latency associated with switching from being served by a first cell to being served by a second cell are provided.

[0029] The detailed description set forth below in connection with the appended drawings is a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. For the purpose of providing a thorough understanding of the various concepts, the detailed description includes specific details. However, the concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

[0030] Certain aspects of a telecommunications system are presented with reference to various devices and methods. These devices and methods are described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using either electronic hardware, computer software, or any combination thereof. Whether an element is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

[0031] By way of example, an element, or any portion of an element, or any combination of elements can be implemented as a "processing system" that includes one or more processors. When multiple processors are implemented, the multiple processors can perform functions individually or in combination. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on a chip (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic components, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout this disclosure. One or more processors in the processing system can execute software. Software should be broadly construed to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, or any combination thereof, regardless of whether it is referred to as software, firmware, middleware, microcode, hardware description language, or other terms.

[0032] Thus, in one or more example aspects, embodiments, and / or use cases, the described functionality can be implemented in hardware, software, or any combination thereof. If implemented in software, the functionality can be stored or encoded on a computer-readable medium as one or more instructions or code. Computer-readable media includes computer storage media. Storage media can be any available medium that can be accessed by a computer. By way of example, such computer-readable media can include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of these types of computer-readable media, or any other medium that can be used to store computer-executable code in the form of instructions or data structures that can be accessed by a computer.

[0033] While aspects, embodiments, and / or use cases are described herein by way of illustration of some examples, additional or different aspects, embodiments, and / or use cases may arise in many different arrangements and scenarios. The aspects, embodiments, and / or use cases described herein may be implemented across many different platform types, devices, systems, shapes, sizes, and packaging arrangements. For example, aspects, embodiments, and / or use cases may be embodied via integrated chips and other non-module-component-based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail / purchase devices, medical devices, artificial intelligence (AI)-enabled devices, etc.). While some examples may or may not be specifically targeted at a use case or application, the examples described may have broad applicability. Aspects, embodiments, and / or use cases may range from chip-level or modular components to non-modular, non-chip-level embodiments, and further to aggregated, distributed, or original equipment manufacturer (OEM) devices or systems incorporating one or more of the techniques herein. In some practical settings, devices incorporating the aspects and features described herein may also include additional components and features for implementing and practicing the claimed and described aspects. For example, the transmission and reception of wireless signals necessarily includes multiple components for analog and digital purposes (e.g., hardware components including antennas, RF chains, power amplifiers, modulators, buffers, processors, interleavers, adders / summers, etc.). The techniques described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, aggregated components, or disaggregated components, end-user devices, etc., of various sizes, shapes, and configurations.

[0034] The deployment of a communication system (such as a 5G NR system) can be arranged with various components or constituent parts in a variety of ways. In a 5G NR system or network, network nodes, network entities, mobility elements of the network, radio access network (RAN) nodes, core network nodes, network elements, or network equipment (such as a base station (BS)) or one or more units (or one or more components) performing base station functionality may be implemented in an aggregated or disaggregated architecture. For example, a BS (such as a Node B (NB), evolved NB (eNB), NR BS, 5G NB, access point (AP), transmit receive point (TRP), or cell, etc.) may be implemented as an aggregated base station (also referred to as a stand-alone BS or monolithic BS) or a disaggregated base station.

[0035] A centralized base station can be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node. A split base station can be configured to utilize a protocol stack that is physically or logically distributed across two or more units, such as one or more central or centralized units (CUs), one or more distributed units (DUs), or one or more radio units (RUs). In some aspects, a CU can be implemented within a RAN node, and one or more DUs can be co-located with the CU, or alternatively, can be geographically or virtually distributed across one or more other RAN nodes. A DU can be implemented to communicate with one or more RUs. Each of the CU, DU, and RU can be implemented as a virtual unit, i.e., a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU).

[0036] Base station operation or network design can consider the aggregation characteristics of base station functionality. For example, split base stations can be used in an integrated access backhaul (IAB) network, an open radio access network (O-RAN, such as a network configuration advocated by the O-RAN Alliance), or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN)). Splitting can include distributing functionality across two or more units at various physical locations, as well as virtually distributing the functionality of at least one unit, which can achieve flexibility in network design. The various units of a split base station or a split RAN architecture can be configured for wired or wireless communication with at least one other unit.

[0037] Figure 1 FIG. 100 is a diagram illustrating an example of a wireless communication system and an access network. The illustrated wireless communication system includes a split base station architecture. The split base station architecture can include one or more CUs 110, which can communicate directly with the core network 120 via a backhaul link, or indirectly with the core network 120 through one or more split base station units, such as a near real-time (near RT) RAN intelligent controller (RIC) 125 via an E2 link, or a non-real-time (non RT) RIC 115 associated with a service management and orchestration (SMO) framework 105, or both. The CU 110 can communicate with one or more DUs 130 via a respective midhaul link, such as an F1 interface. The DU 130 can communicate with one or more RUs 140 via a respective fronthaul link. The RU 140 can communicate with a respective UE 104 via one or more radio frequency (RF) access links. In some embodiments, the UE 104 can be served simultaneously by multiple RUs 140.

[0038] Each unit (i.e., CU 110, DU 130, RU 140, and the near RT RIC 125, non-RT RIC 115, and SMO framework 105) may include one or more interfaces or be coupled to one or more interfaces that are configured to receive or transmit signals, data, or information (collectively referred to as signals) via a wired or wireless transmission medium. Each of the units or the associated processor or controller that provides instructions to the communication interfaces of these units may be configured to communicate with one or more of the other units via the transmission medium. For example, the units may include a wired interface that is configured to receive signals or transmit signals to one or more of the other units via a wired transmission medium. Additionally, the units may include a wireless interface that may include a receiver, transmitter, or transceiver (such as an RF transceiver) that is configured to receive and / or transmit signals to one or more of the other units via a wireless transmission medium.

[0039] In some aspects, CU 110 may host one or more higher layer control functions. Such control functions may include Radio Resource Control (RRC), Packet Data Convergence Protocol (PDCP), Service Data Adaptation Protocol (SDAP), etc. Each control function may utilize an interface that is configured to communicate signals with other control functions hosted by CU 110. CU 110 may be configured to handle user plane functionality (i.e., Central Unit → User Plane (CU-UP)), control plane functionality (i.e., Central Unit → Control Plane (CU-CP)), or a combination thereof. In some embodiments, CU 110 may be logically split into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP units may communicate bidirectionally with the CU-CP units via an interface (such as an E1 interface). As needed, CU 110 may be implemented to communicate with DU 130 for network control and signaling.

[0040] DU 130 may correspond to a logical unit that includes one or more base station functions for controlling the operation of one or more RUs 140. In some aspects, DU 130 may host one or more of the Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, and one or more high Physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation, and demodulation, etc.) at least partially according to a functional split (such as those defined by 3GPP). In some aspects, DU 130 may further host one or more low PHY layers. Each layer (or module) may utilize an interface that is configured to communicate signals with other layers (and modules) hosted by DU 130 or with the control functions hosted by CU 110.

[0041] The lower layer functionality can be implemented by one or more RUs 140. In some deployments, the RUs 140 controlled by the DU 130 can correspond to logical nodes that host RF processing functions or low PHY layer functions (such as performing fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, etc.) or both, at least in part based on function splitting (such as lower layer function splitting). In such an architecture, the RU 140 can be implemented to handle over-the-air (OTA) communication with one or more UEs 104. In some embodiments, the real-time and non-real-time aspects of communicating with the control plane and user plane of the RU 140 can be controlled by the corresponding DU 130. In some scenarios, this configuration enables the implementation of the DU 130 and CU 110 in a cloud-based RAN architecture (such as a vRAN architecture).

[0042] The SMO framework 105 can be configured to support the deployment and orchestration of RAN for both non-virtualized network elements and virtualized network elements. For non-virtualized network elements, the SMO framework 105 can be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which can be managed via an operation and maintenance interface (such as the O1 interface). For virtualized network elements, the SMO framework 105 can be configured to interact with a cloud computing platform (such as the Open Cloud (O-Cloud) 190) to perform network element lifecycle management (such as instantiating virtualized network elements) via a cloud computing platform interface (such as the O2 interface). Such virtualized network elements can include, but are not limited to, the CU 110, DU 130, RU 140, and near RT RIC 125. In some embodiments, the SMO framework 105 can communicate with the hardware aspects of the 4G RAN (such as the Open eNB (O-eNB) 111) via the O1 interface. Additionally, in some embodiments, the SMO framework 105 can communicate directly with one or more RUs 140 via the O1 interface. The SMO framework 105 can also include a non-RT RIC 115 configured to support the functionality of the SMO framework 105.

[0043] The non-RT RIC 115 can be configured to include logic functions that enable non-real-time control and optimization of RAN elements and resources, artificial intelligence (AI) / machine learning (ML) (AI / ML) workflows including model training and update, or policy-based guidance of applications / features in the near-RT RIC 125. The non-RT RIC 115 can be coupled to or communicate with the near-RT RIC 125 (such as via the A1 interface). The near-RT RIC 125 can be configured to include logic functions that enable near-real-time control and optimization of RAN elements and resources via data collection and actions through an interface (such as via the E2 interface), which connects one or more CUs 110, one or more DUs 130, or both, and the O-eNB to the near-RT RIC 125.

[0044] In some specific implementations, to generate an AI / ML model to be deployed in the near-RT RIC 125, the non-RT RIC 115 can receive parameters or external enrichment information from an external server. Such information can be utilized by the near-RT RIC 125 and can be received from non-network data sources or from network functions at the SMO framework 105 or the non-RT RIC 115. In some examples, the non-RT RIC 115 or the near-RT RIC 125 can be configured to regulate RAN behavior or performance. For example, the non-RT RIC 115 can monitor long-term trends and patterns of performance and employ an AI / ML model to perform corrective actions through the SMO framework 105 (such as reconfiguration via O1) or via creating RAN management policies (such as A1 policies).

[0045] At least one of CU 110, DU 130, and RU 140 may be referred to as base station 102. Thus, base station 102 may include one or more of CU 110, DU 130, and RU 140 (each component is indicated by a dashed line to indicate that each component may or may not be included in base station 102). Base station 102 provides an access point to core network 120 for UE 104. Base station 102 may include macro cells (high-power cellular base stations) and / or small cells (low-power cellular base stations). Small cells include femto cells, pico cells, and micro cells. A network including both small cells and macro cells may be referred to as a heterogeneous network. The heterogeneous network may also include a home evolved Node B (eNB) (HeNB), which may provide services to a restricted group referred to as a closed subscriber group (CSG). The communication link between RU 140 and UE 104 may include an uplink (UL) (also referred to as a reverse link) transmission from UE 104 to RU 140 and / or a downlink (DL) (also referred to as a forward link) transmission from RU 140 to UE 104. The communication link may use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link may pass through one or more carriers. For each carrier allocated in carrier aggregation with a total of up to Yx MHz (x component carriers) for transmission in each direction, base station 102 / UE 104 may use a spectrum with a bandwidth of up to Y MHz (e.g., 5 MHz, 10 MHz, 15 MHz, 20 MHz, 100 MHz, 400 MHz, etc.). These carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL compared to UL). Component carriers may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell) and the secondary component carriers may be referred to as secondary cells (SCells).

[0046] Some UEs 104 may use device-to-device (D2D) communication link 158 to communicate with each other. D2D communication link 158 may use DL / UL wireless wide area network (WWAN) spectrum. D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). D2D communication may be carried out through various wireless D2D communication systems, such as for example Bluetooth TM (Bluetooth is a trademark of the Bluetooth Special Interest Group (SIG)), Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard TM (Wi-Fi is a trademark of the Wi-Fi Alliance), LTE, or NR.

[0047] The wireless communication system may also include a Wi-Fi AP 150 that communicates with the UE 104 (also referred to as a Wi-Fi station (STA)) via a communication link 154, for example, in the 5 GHz unlicensed spectrum, etc. When communicating in the unlicensed spectrum, the UE 104 / AP 150 may perform a Clear Channel Assessment (CCA) before communication to determine whether the channel is available.

[0048] The electromagnetic spectrum is generally subdivided into various categories, frequency bands, channels, etc. based on frequency / wavelength. In 5G NR, two initial operating frequency bands have been identified as Frequency Range Designation FR1 (410 MHz → 7.125 GHz) and FR2 (24.25 GHz - 52.6 GHz). Although a part of FR1 is greater than 6 GHz, in various documents and articles, FR1 is generally (interchangeably) referred to as the "sub-6 GHz" band. Regarding FR2, a similar naming issue sometimes occurs, which is generally (interchangeably) referred to as the "millimeter wave" band in documents and articles, although it is different from the Extremely High Frequency (EHF) band (30 GHz - 300 GHz) identified by the International Telecommunication Union (ITU) as the "millimeter wave" band.

[0049] The frequencies between FR1 and FR2 are generally referred to as mid-band frequencies. Recent 5G NR research has identified the operating frequency bands for these mid-band frequencies as Frequency Range Designation FR3 (7.125 GHz - 24.25 GHz). The frequency bands falling within FR3 may inherit FR1 characteristics and / or FR2 characteristics, and thus can effectively extend the features of FR1 and / or FR2 to the mid-band frequencies. In addition, higher frequency bands are currently being explored to extend 5G NR operations beyond 52.6 GHz. For example, three higher operating frequency bands have been identified as Frequency Range Designation FR2-2 (52.6 GHz - 71 GHz), FR4 (71 GHz → 114.25 GHz), and FR5 (114.25 GHz - 300 GHz). Each of these higher frequency bands falls within the EHF band.

[0050] Considering the above aspects, unless otherwise specifically stated, if the term "sub-6 GHz" etc. is used in this document, it may broadly represent frequencies that can be less than 6 GHz, can be within FR1, or can include mid-band frequencies. In addition, unless otherwise specifically stated, if the term "millimeter wave" etc. is used in this document, it may broadly represent frequencies that can include mid-band frequencies, can be within FR2, FR4, FR2-2, and / or FR5, or can be within the EHF band.

[0051] Base station 102 and UE 104 may each include multiple antennas (such as antenna elements, antenna panels, and / or antenna arrays) to facilitate beamforming. Base station 102 may transmit beamformed signal 182 to UE 104 in one or more transmission directions. UE 104 may receive the beamformed signal from base station 102 in one or more reception directions. UE 104 may also transmit beamformed signal 184 to base station 102 in one or more transmission directions. Base station 102 may receive the beamformed signal from UE 104 in one or more reception directions. Base station 102 / UE 104 may perform beam training to determine the optimal reception direction and transmission direction for each of base station 102 / UE 104. The transmission direction and reception direction of base station 102 may be the same or may not be the same. The transmission direction and reception direction of UE 104 may be the same or may not be the same.

[0052] Base station 102 may include and / or be referred to as gNB, Node B, eNB, access point, transceiver base station, radio base station, radio transceiver, transceiver function, basic service set (BSS), extended service set (ESS), TRP, network node, network entity, network equipment, or some other suitable term. Base station 102 may be implemented as an integrated access and backhaul (IAB) node, a relay node, a sidelink node, an aggregated (monolithic) base station with a baseband unit (BBU) (including CU and DU) and RU, or may be implemented as a disaggregated base station including one or more of CU, DU, and / or RU. A set of base stations that may include disaggregated base stations and / or aggregated base stations may be referred to as a next generation (NG) RAN (NG-RAN).

[0053] The core network 120 may include an Access and Mobility Management Function (AMF) 161, a Session Management Function (SMF) 162, a User Plane Function (UPF) 163, a Unified Data Management (UDM) 164, one or more Location Servers 168, and other functional entities. The AMF 161 is a control node that processes signaling between the UE 104 and the core network 120. The AMF 161 supports registration management, connection management, mobility management, and other functions. The SMF 162 supports session management and other functions. The UPF 163 supports packet routing, packet forwarding, and other functions. The UDM 164 supports the generation of Authentication and Key Agreement (AKA) credentials, user identity handling, access authorization, and subscription management. One or more Location Servers 168 are illustrated as including a Gateway Mobile Location Center (GMLC) 165 and a Location Management Function (LMF) 166. However, generally speaking, one or more Location Servers 168 may include one or more location / locationing servers, which may include one or more of the GMLC 165, LMF 166, a Position Determination Entity (PDE), a Serving Mobile Location Center (SMLC), a Mobile Positioning Center (MPC), etc. The GMLC 165 and LMF 166 support UE location services. The GMLC 165 provides an interface for clients / applications (e.g., emergency services) to access UE location information. The LMF 166 receives measurements and assistance information from the NG-RAN and the UE 104 via the AMF 161 to calculate the location of the UE 104. The NG-RAN may utilize one or more location methods to determine the location of the UE 104. Locating the UE 104 may involve signal measurements, location estimation, and optional speed calculations based on these measurements. The signal measurements may be performed by the UE 104 and / or the base station 102 serving the UE 104. The measured signals may be based on a Satellite Positioning System (SPS) 170 (e.g., a Global Navigation Satellite System (GNSS), a Global Positioning System (GPS), a Non-Terrestrial Network (NTN), or one or more of other satellite positioning / location systems), an LTE signal, a Wireless Local Area Network (WLAN) signal, a Bluetooth signal, a Terrestrial Beacon System (TBS), sensor-based information (e.g., an atmospheric pressure sensor, a motion sensor), an NR Enhanced Cell ID (NR E-CID) method, an NR signal (e.g., multi-round-trip time (multi-RTT), DL Angle of Departure (DL-AoD), DL Time Difference of Arrival (DL-TDOA), UL Time Difference of Arrival (UL-TDOA), and UL Angle of Arrival (UL-AoA) positioning), and / or one or more of other systems / signals / sensors.

[0054] Examples of the UE 104 include cellular phones, smart phones, Session Initiation Protocol (SIP) phones, laptop computers, personal digital assistants (PDAs), satellite radios, global positioning systems, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, tablet computers, smart devices, wearable devices, transportation vehicles, electricity meters, air pumps, large or small kitchen appliances, healthcare devices, implants, sensors / actuators, displays, or any other device with similar functionality. Some of the UEs in the UE 104 may be referred to as IoT devices (e.g., parking meters, air pumps, toasters, transportation vehicles, heart monitors, etc.). The UE 104 may also be referred to as a station, mobile station, subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, cell phone, user agent, mobile client, client, or some other suitable term. In some scenarios, the term UE may also apply to one or more companion devices, such as in a device cluster arrangement. One or more of these devices may access the network jointly and / or access the network individually.

[0055] Referring again to Figure 1 , in certain aspects, the UE 104 may include an inter-cell TCI RS measurement (ITRM) component 198, which may be configured to receive from a network node a first indication for the UE to hand over from being served by a first cell to being served by a second cell. The ITRM component 198 may also be configured to receive a second indication for the UE to use a TCI state, where the second indication is received at a timing after the first indication based on the relationship between the TCI state and one or more reference signals measured by the UE before receiving the first indication for the handover to the second cell. The ITRM component 198 may also be configured to communicate with the network node via the second cell and using the TCI state. In certain aspects, the base station 102 may include an inter-cell TCI RS configuration (ITRC) component 199, which may be configured to indicate to the UE to hand over from being served by a first cell to being served by a second cell. The ITRC component 199 may also be configured to indicate the TCI state for the UE to use with the second cell, where the indication is performed at a timing based on the relationship between the TCI state and one or more reference signals measured by the UE before the handover to the second cell. The ITRC component 199 may also be configured to communicate with the UE via the second cell and using the TCI state. Although the following description may focus on 5G NR, the concepts described herein may be applicable to other similar fields, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0056] Figure 2AFIG. 200 is an illustration example of a first subframe within a 5G NR frame structure. Figure 2B FIG. 230 is an illustration example of a DL channel within a 5G NR subframe. Figure 2C FIG. 250 is an illustration example of a second subframe within a 5G NR frame structure. Figure 2D FIG. 280 is an illustration example of a UL channel within a 5G NR subframe. The 5G NR frame structure can be frequency division duplexing (FDD) (wherein for a specific set of subcarriers (carrier system bandwidth), the subframes within that set of subcarriers are dedicated to DL or UL), or can be time division duplexing (TDD) (wherein for a specific set of subcarriers (carrier system bandwidth), the subframes within that set of subcarriers are dedicated to both DL and UL). In Figure 2A , Figure 2C the example provided, the 5G NR frame structure is assumed to be TDD, where subframe 4 is configured with slot format 28 (where most are DL), where D is DL, U is UL, and F is flexibly usable between DL / UL, and subframe 3 is configured with slot format 1 (where all are UL). Although subframes 3, 4 are shown as having slot formats 1, 28 respectively, any particular subframe can be configured with any of the various available slot formats 0 - 61. Slot formats 0, 1 are full DL, full UL respectively. The other slot formats 2 - 61 include a mixture of DL, UL, and flexible symbols. The UE is configured with the slot format by receiving a slot format indicator (SFI) (configured dynamically by DL control information (DCI) or semi-statically / statically by radio resource control (RRC) signaling). Note that the following description also applies to the 5G NR frame structure as TDD.

[0057] Figures 2A to 2DThe frame structure is illustrated, and aspects of the present disclosure may be applicable to other wireless communication technologies that may have different frame structures and / or different channels. A frame (10 ms) may be divided into 10 equal-sized subframes (1 ms). Each subframe may include one or more time slots. The subframe may also include mini-slots, which may include 7, 4, or 2 symbols. Each time slot may include 14 or 12 symbols, depending on whether the cyclic prefix (CP) is normal or extended. For normal CP, each time slot may include 14 symbols, and for extended CP, each time slot may include 12 symbols. The symbols on the DL may be CP orthogonal frequency division multiplexing (OFDM) (CP-OFDM) symbols. The symbols on the UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (for power-constrained scenarios; limited to single-stream transmission). The number of time slots within a subframe is based on the CP and the parameter set. The parameter set defines the subcarrier spacing (SCS) (see Table 1). The symbol length / duration may be scaled with 1 / SCS.

[0058]

[0059] Table 1: Parameter Sets, SCS, and CP

[0060] For normal CP (14 symbols / slot), different parameter sets μ 0 to 4 allow 1, 2, 4, 8, and 16 time slots per subframe, respectively. For extended CP, parameter set 2 allows 4 time slots per subframe. Thus, for normal CP and parameter set μ, there are 14 symbols / slot and 2μ time slots / subframe. The subcarrier spacing may be equal to 2μ * 15 kHz, where μ is parameter set 0 to 4. Thus, the subcarrier spacing for parameter set μ = 0 is 15 kHz, and the subcarrier spacing for parameter set μ = 4 is 240 kHz. The symbol length / duration is negatively correlated with the subcarrier spacing. Figures 2A to 2D An example is provided with normal CP having 14 symbols per time slot and parameter set μ = 2 having 4 time slots per subframe. The time slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs. Within a frame set, there may be one or more different bandwidth parts (BWPs) that are frequency division multiplexed (see Figure 2B ). Each BWP may have a specific parameter set and CP (normal or extended).

[0061] A resource grid may be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as a physical RB (PRB)) that extends 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0062] AsFigure 2A As illustrated, some of the REs in the RE carry reference (pilot) signals (RS) for the UE. The RS may include demodulation RS (DM-RS) (designated as R for a particular configuration, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RS) for channel estimation at the UE. The RS may also include beam measurement RS (BRS), beam refinement RS (BRRS), and phase tracking RS (PT-RS).

[0063] Figure 2B Examples of various DL channels within a subframe of a frame are illustrated. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) (e.g., 1, 2, 4, 8, or 16 CCEs), each CCE including six resource element groups (REGs), each REG including 12 consecutive RES in the OFDM symbols of an RB. The PDCCH within a BWP may be referred to as a control resource set (CORESET). The UE is configured to monitor PDCCH candidates in the PDCCH search space (e.g., common search space, UE-specific search space) during PDCCH monitoring occasions on the CORESET, where the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs may be located at higher and / or lower frequencies on the channel bandwidth. The primary synchronization signal (PSS) may be in symbol 2 of a particular subframe of a frame. The PSS is used by the UE 104 to determine subframe / symbol timing and the physical layer identity. The secondary synchronization signal (SSS) may be in symbol 4 of a particular subframe of a frame. The SSS is used by the UE to determine the physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE may determine the physical cell identifier (PCI). Based on the PCI, the UE may determine the location of the DM-RS. The physical broadcast channel (PBCH) carrying the master information block (MIB) may be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block (also referred to as an SS block (SSB)). The MIB provides the system frame number (SFN) and the number of RBs in the system bandwidth. The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted via the PBCH (such as system information blocks (SIBs)), and paging messages.

[0064] As Figure 2CAs illustrated, some of the REs in the RE carry DM-RS (indicated as R for a specific configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE can transmit the DM-RS of the physical uplink control channel (PUCCH) and the DM-RS of the physical uplink shared channel (PUSCH). The PUSCH DM-RS can be transmitted in the previous one or two symbols of the PUSCH. Depending on whether a short PUCCH or a long PUCCH is transmitted and depending on the specific PUCCH format used, the PUCCH DM-RS can be transmitted in different configurations. The UE can transmit a sounding reference signal (SRS). The SRS can be transmitted in the last symbol of the subframe. The SRS can have a comb structure, and the UE can transmit the SRS on one of the teeth of the comb. The SRS can be used by the base station for channel quality estimation to enable frequency-dependent scheduling of the UL.

[0065] Figure 2D Examples of various UL channels within a subframe of a frame are illustrated. The PUCCH can be located at the position indicated in one configuration. The PUCCH carries uplink control information (UCI), such as a scheduling request, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and a hybrid automatic repeat request (HARQ) acknowledgment (ACK) (HARQ-ACK) feedback (i.e., one or more HARQ ACK bits indicating one or more ACKs and / or negative ACKs (NACKs)). The PUSCH carries data and can additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0066] Figure 3It is a block diagram of the communication between the base station 310 and the UE 350 in the access network. In the DL, Internet Protocol (IP) packets can be provided to the controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes the Radio Resource Control (RRC) layer, and layer 2 includes the Service Data Adaptation Protocol (SDAP) layer, the Packet Data Convergence Protocol (PDCP) layer, the Radio Link Control (RLC) layer, and the Medium Access Control (MAC) layer. The controller / processor 375 provides RRC layer functionality associated with the broadcast of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs), error correction via ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; and MAC layer functionality associated with the mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0067] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1, which includes the physical (PHY) layer, may include error detection on the transport channel, forward error correction (FEC) encoding / decoding of the transport channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 handles the mapping to signal constellations based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase phase shift keying (M-PSK), M-order quadrature amplitude modulation (M-QAM)). The encoded and modulated symbols may then be split into parallel streams. Subsequently, each stream may be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., a pilot) in the time domain and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time-domain OFDM symbol stream. The OFDM stream is precoded in space to generate multiple spatial streams. Channel estimates from the channel estimator 374 may be used to determine the encoding and modulation schemes, as well as for spatial processing. The channel estimates may be derived from reference signals transmitted by the UE 350 and / or channel state feedback. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318Tx. Each transmitter 318Tx may modulate a radio frequency (RF) carrier with the corresponding spatial stream for transmission.

[0068] At the UE 350, each receiver 354Rx receives signals via its corresponding antenna 352. Each receiver 354Rx recovers the information modulated onto the RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they may be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then uses a fast Fourier transform (FFT) to convert the OFDM symbol stream from the time domain to the frequency domain. The frequency-domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols and reference signals on each subcarrier are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. These soft decisions may be based on the channel estimates computed by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted by the base station 310 on the physical channel. The data and control signals are then provided to the controller / processor 359, which implements layer 3 and layer 2 functionality.

[0069] The controller / processor 359 may be associated with at least one memory 360 that stores program code and data. The at least one memory 360 may be referred to as a computer-readable medium. In the UL, the controller / processor 359 provides demultiplexing between the transport channel and the logical channel, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets. The controller / processor 359 is also responsible for error detection using the ACK and / or NACK protocols to support HARQ operations.

[0070] Similar to the functionality described in connection with DL transmissions performed by the base station 310, the controller / processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functionality associated with header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functionality associated with the transfer of upper layer PDUs, error correction via ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; and MAC layer functionality associated with the mapping between the logical channel and the transport channel, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0071] Channel estimates derived by the channel estimator 358 based on reference signals or feedback transmitted by the base station 310 may be used by the TX processor 368 to select appropriate decoding and modulation schemes and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via a separate transmitter 354Tx. Each transmitter 354Tx modulates an RF carrier with the corresponding spatial stream for transmission.

[0072] UL transmissions are processed at the base station 310 in a manner similar to that described in connection with the receiver functionality at the UE 350. Each receiver 318Rx receives signals via its corresponding antenna 320. Each receiver 318Rx recovers the information modulated onto the RF carrier and provides the information to the RX processor 370.

[0073] The controller / processor 375 may be associated with at least one memory 376 that stores program code and data. The at least one memory 376 may be referred to as a computer-readable medium. In the UL, the controller / processor 375 provides demultiplexing between the transport channel and the logical channel, packet reassembly, decryption, header decompression, control signal processing to recover IP packets. The controller / processor 375 is also responsible for error detection using the ACK and / or NACK protocols to support HARQ operations.

[0074] At least one of TX processor 368, RX processor 356, and controller / processor 359 may be configured to perform aspects related to Figure 1 the ITRM component 198.

[0075] At least one of TX processor 316, RX processor 370, and controller / processor 375 may be configured to perform aspects related to Figure 1 the ITRC component 199.

[0076] The network may communicate with the UE based on one or more beams (spatial filters). For example, a base station of the network may send beamformed signals to the UE in one or more directions corresponding to one or more beams. The base station and the UE may perform beam training to determine the optimal receive and transmit directions of the base station and the UE.

[0077] Beams may be switched in response to different conditions. For example, a transmission configuration indication (TCI) state change may be sent by the base station so that the UE may switch to a new beam for the TCI state. This TCI state change may enable the UE to find the best UE receive beam corresponding to the TCI state from the base station and switch to such a beam. Switching beams may allow for enhanced or improved connection between the UE and the base station by ensuring that the transmitter and receiver communicate using the same configured set of beams. The TCI state may include quasi-co-location (QCL) information, which the UE may use to derive timing / frequency errors and / or transmit / receive spatial filtering for transmitting / receiving signals.

[0078] The different procedures for managing and controlling beams for wireless communication may be collectively referred to as "beam management". The process of selecting a beam to switch to for a data channel or a control channel may be referred to as "beam selection".

[0079] As an example, the UE may encounter two types of mobility → cell-level mobility and beam-level mobility (which may be beam-based mobility). For cell-level mobility, the UE may experience an inter-cell handover. In some wireless communication systems, for beam-level mobility, as previously explained, the switching of beams may occur within the same cell.

[0080] For example, inter-cell beam management based on beam-based mobility may be facilitated by L1 and / or L2 signaling, such as UE-specific channels / RSs, which may be associated with a TRP having a different PCI according to a unified TCI update based on downlink control information (DCI) or medium access control (MAC) control element (MAC-CE). As used herein, such mobility may be referred to as L1 / L2 mobility.

[0081] In some aspects, the network may configure a set of cells for L1 / L2 mobility. This set of cells for L1 / L2 mobility may be referred to as the L1 / L2 mobility configured cell set. A subset of the L1 / L2 mobility configured cell set may be activated (e.g., using L1 or L2 control signaling) and may be referred to as the L1 / L2 mobility activated cell set (which may also be referred to as the L1 / L2 activated mobility cell set). A subset of cells in the L1 / L2 mobility configured cell set that are not activated or are indicated to be deactivated may be referred to as the L1 / L2 mobility deactivated cell set or the deactivated L1 / L2 mobility cell set. The L1 / L2 mobility activated cell set may be a set of cells in the L1 / L2 mobility configured cell set that are activated and can be readily used for data and control transfer. The L1 / L2 mobility deactivated cell set (which may be the L1 / L2 mobility candidate cell set) may be a set of cells in the configured set that are configured for a UE that has not been deactivated (e.g., not used for data / control transfer before activation) and can be activated by L1 / L2 signaling. Once activated, the deactivated cells can be used for data and control transfer between the UE and the base station. L1 / L2 inter-cell mobility can reduce mobility latency. The configuration and maintenance of multiple candidate cells may allow for a faster application of the configuration for the candidate cells, and the activated cell set may provide dynamic switching between candidate serving cells (e.g., including SpCell and SCell) based on L1 or L2 signaling.

[0082] The procedures for L1 / L2-based inter-cell mobility apply to many scenarios. These scenarios may include, but are not limited to, the stand-alone CA and NR-DC cases where the serving cell changes within a CG, the in-DU case, and the inter-DU case within the CU (applicable to both stand-alone and CA where a new RAN interface is not desired), the intra-frequency and inter-frequency cases, and the FR1 and FR2 cases. In these scenarios, the source cell and the target cell may be synchronous or asynchronous.

[0083] For mobility management of the active cell set, L1 / L2 signaling can be used to activate / deactivate cells in the L1 / L2 mobility configured cell set and select a beam within the active cells (of the active cell set). As the UE moves, cells from the L1 / L2 mobility configured cell set can be deactivated and activated by L1 / L2 signaling based on signal quality (e.g., based on measurements), load, etc. Example measurements can include cell coverage measurements represented by radio signal received power (RSRP) and quality represented by radio signal received quality (RSRQ), or other measurements performed by the UE on signals from the base station. In some aspects, these measurements can be L1 measurements, such as one or more of RSRP, RSRQ, received signal strength indicator (RSSI), or signal-to-noise interference ratio (SINR) measurements of various signals (such as SSB, PSS, SSS, broadcast channel (BCH), DM-RS, CSI-RS, etc.).

[0084] In some aspects of wireless communication (e.g., 5G NR), a UE in motion can experience multiple inter-cell handovers during which the UE served by a first cell switches to being served by a second cell. In some aspects, the UE can be configured to communicate with multiple candidate cells such that if the communication quality with the current serving cell (e.g., the primary cell or PCell) among the multiple candidate cells is below a threshold quality, the UE can switch to being served by a second cell (e.g., a secondary cell or SCell in the candidate SCell set) among the multiple cells. In some aspects, the configuration of the multiple candidate cells can be via layer 3 (L3) signaling such as RRC signaling. In some aspects, the indication for switching between being served by the first cell and being served by the second cell can be associated with layer 2 (L2) or layer 1 (L1) signaling. For example, an indication for switching between the first cell and the second cell can be received via one or more L2 signals (e.g., one or more MAC-CEs).

[0085] In some aspects, during a handover operation, the UE may perform additional beam training and / or management (BM) operations associated with a set of TCI states before communicating via a second cell using the TCI states in the set of TCI states, which is selected from a pool of TCI states associated with the second cell. The set of TCI states may be indicated from a network node (e.g., a base station) via a MAC-CE (or other L2 signaling). In some aspects, the additional BM operations may be based on reference signals received after an indication for activating the set of TCI states. Thus, communication via the second cell may involve additional latency associated with waiting for the next instance of a reference signal associated with the activated TCI state before transmitting an indication for communicating using the TCI state (e.g., via DCI or other L1 signaling). The additional latency may be associated with the periodicity of the associated reference signal (e.g., 20 ms for a Synchronization Signal Block (SSB)). A method and apparatus for reducing latency associated with handover from serving by a first cell to serving by a second cell are provided.

[0086] In some aspects, the method and apparatus may utilize reference signals measured when the UE is served by a first cell (e.g., reference signals measured by the UE before receiving an indication to handover to a second cell). In some aspects, the method or apparatus may instruct the UE to maintain measurement information regarding one or more reference signals measured when served by the first cell. In some aspects, the method or apparatus may maintain mapping information regarding the relationship between reference signals and TCI states associated with the second cell to identify newly activated TCI states for which reference signals (e.g., CSI-RS or SSB) have been measured, thereby reducing additional latency introduced by waiting for reference signal transmissions.

[0087] Figure 4A FIG. 400 illustrates aspects of a timeline associated with TCI state activation. Figure 4A Illustrative DL TCI state activation 402 may occur at time t 0 sent by a network node and received by the UE. The UE may transmit a HARQ-ACK 404 at time t 1 The TCI state activation 402 may be processed before time t 2 which, in some aspects, may be the earliest time at which the UE can implement the TCI state (e.g., the earliest time at which the UE may start monitoring and / or measuring the RS associated with the TCI state). To be able to communicate using the TCI, in some aspects, the UE measures at least one RS associated with the TCI state (e.g., at t 3at SSB 408), to derive timing / frequency error for transmitting / receiving signals using the TCI state and / or transmit / receive spatial filtering. In some aspects, the at least one RS may be received within a window as long as the period of the at least one RS, which in some cases may result in an impractical delay (e.g., a delay so long that the TCI state is no longer useful at time t when the UE has completed RS processing). 4 No longer useful).

[0088] Figure 4B FIG. 450 is a diagram illustrating aspects of a timeline associated with TCI state activation. Figure 4B Illustrative UL TCI state activation 452 may be sent by a network node and received by a UE. The UE may send a HARQ-ACK 454 at time t. 0 The TCI state activation 452 may be processed before time t, which in some aspects may be the earliest time at which the UE can implement the TCI state (e.g., the earliest time at which the UE may start monitoring and / or measuring the RS associated with the TCI state). To be able to communicate using the TCI, in some aspects, the UE measures a set of reference signals associated with the TCI state (e.g., the PL reference signal 458 ending at time t), to derive timing / frequency error for transmitting / receiving signals using the TCI state and / or transmit / receive spatial filtering. In some aspects, the set of reference signals may be received within a window as long as a multiple of the period of the RS, based on the number of instances and / or repetitions of the measured RS, which in some cases may result in an impractical delay (e.g., a delay so long that the TCI state is no longer useful at time t when the UE has completed processing the set of reference signals). 1 The TCI state activation 452 may be processed before time t, which in some aspects may be the earliest time at which the UE can implement the TCI state (e.g., the earliest time at which the UE may start monitoring and / or measuring the RS associated with the TCI state). To be able to communicate using the TCI, in some aspects, the UE measures a set of reference signals associated with the TCI state (e.g., the PL reference signal 458 ending at time t), to derive timing / frequency error for transmitting / receiving signals using the TCI state and / or transmit / receive spatial filtering. In some aspects, the set of reference signals may be received within a window as long as a multiple of the period of the RS, based on the number of instances and / or repetitions of the measured RS, which in some cases may result in an impractical delay (e.g., a delay so long that the TCI state is no longer useful at time t when the UE has completed processing the set of reference signals). 2 before. In some aspects, this time may be the earliest time at which the UE can implement the TCI state (e.g., the earliest time at which the UE may start monitoring and / or measuring the RS associated with the TCI state). To be able to communicate using the TCI, in some aspects, the UE measures a set of reference signals associated with the TCI state (e.g., the PL reference signal 458 ending at time t), to derive timing / frequency error for transmitting / receiving signals using the TCI state and / or transmit / receive spatial filtering. In some aspects, the set of reference signals may be received within a window as long as a multiple of the period of the RS, based on the number of instances and / or repetitions of the measured RS, which in some cases may result in an impractical delay (e.g., a delay so long that the TCI state is no longer useful at time t when the UE has completed processing the set of reference signals). 3 ending). 4 No longer useful).

[0089] Figure 5 FIG. 500 is a diagram illustrating that a UE 504 experiences a mobility event (e.g., a handover or a handoff) due to moving from a first location to a second location, according to some aspects of the present disclosure. The UE 504 may be configured to communicate with a cell 508a as a primary (or serving) cell before the movement, and may be configured to communicate with a cell 508d as a primary (or serving) cell after the movement. In some aspects, a cell group including the cells 508a, 508b, 508c, and 508d may be configured for carrier aggregation (CA) or dual connectivity (DC), while in other aspects, it may be a preconfigured PCell candidate in the absence of CA or DC.

[0090] Figure 6FIG. 600 is a call flow diagram illustrating a wireless communication method for reducing latency during a handover of a UE 602 from being served by a first cell 606 to being served by a second cell 608 in a cell group associated with a network node 604, in accordance with some aspects of the present disclosure. In some aspects, the UE 602 may send a UE capability indication 610, and the first cell 606 may receive the UE capability indication. The first cell 606 may be a primary cell for communicating control messages between the UE 602 and a network (or network node) associated with the cell group associated with the network node 604. In some aspects, the UE capability indication 610 may be related to the buffer and / or memory size of the UE for storing RS measurements and / or information. Thus, in some aspects, the UE capability indication 610 indicates the capacity of the UE to store RS measurements. For example, the UE capability indication 610 may indicate (1) the total number of reference signals; or (2) the number of cells for which measurements can be maintained and the number of reference signals per cell, along with an indication of how long the information can be maintained. RS measurement information that exceeds the indicated capability (e.g., for RS measurements outside the indicated time period or for RS measurements exceeding the indicated total number) may be assumed to be erased in a first-in-first-out (FIFO) manner to capture new RS measurement information. In some aspects, the UE capability indication 610 may be included in an initial (or L3) configuration action set. The network node may then indicate parameters for RS measurement maintenance, such as the number of RS measurements to be maintained and / or the time period for maintaining the RS measurements. In some aspects, the parameters for RS measurement maintenance may be known parameters based on the capacity indicated in the UE capability indication 610.

[0091] In some aspects, the first cell 606 may send an indication 612 of a set of reference signals to be monitored and / or TCI states to be activated, and the UE 602 may receive the indication. In some aspects, the indication 612 may include an indication for maintaining associated RS measurement information and parameters such as the number of RS measurements to be maintained or the time period for keeping the RS measurements. In some aspects, the indication 612 may be received via a MAC-CE. In some aspects, the activated TCI state is selected from a TCI state pool associated with the serving cell (e.g., the first cell 606). The TCI states in the TCI state pool may be associated with corresponding reference signals, e.g., may be quasi-co-located (QCLed) with them. In some aspects, the QCL between a TCI state and a corresponding RS may indicate that one or more of the frequency offset, timing offset, or spatial characteristics associated with the corresponding reference signal may be applied to the communication associated with the TCI state. In some aspects, the indication 612 may include a set of reference signals and / or TCI states associated with the second cell 608 and / or additional candidate cells (not shown), where the additional candidate cells are associated with a cell group associated with the network node 604. The set of reference signals associated with other cells in the cell group may be configured as the same set of reference signals independent of the identity of the serving cell. To be able to indicate the reference signals or TCI states associated with the second cell 608, in some aspects, a PCI field may be associated with the TCI states in the TCI state pool or may be used to identify the activated TCI state. In some aspects, the indication 612 may include an indication of a set of TCI states associated with UL transmission, and the associated reference signals may include a set of multiple reference signals (or multiple instances of the same RS) for measuring the path loss (PL) associated with the TCI state.

[0092] Based on the indication 612 of the reference signals and / or TCI states to be activated, the UE 602 may measure the set of reference signals indicated in the indication 612 at 622. The set of reference signals measured at 622 may include one or more of a first RS 614 sent by the first cell 606, a second RS 616 sent by the first cell 606, a third RS 618 sent by the second cell 608, and a fourth RS 620 sent by the second cell 608. In some aspects, the set of reference signals measured at 622 may include additional reference signals (e.g., PL reference signals) sent by the first cell 606, the second cell 608, or other cells in the cell group associated with the network node 604, which are not depicted for clarity.

[0093] The first cell 606 may send an indication 624 for the UE 602 to handover from being served by the first cell 606 to being served by the second cell 608, and the UE 602 may receive the indication. Based on the indication 624, the UE 602 may then handover from being served by the first cell 606 to the second cell 608 at 626 while maintaining the RS measurements made when being served by the first cell 606. In some aspects, the network node 604 may identify at 628 a TCI state associated with, related to, or corresponding to a reference signal in the set of reference signals measured by the UE 602 at 622. At 628, the identification may be based on mapping information regarding the relationship between the reference signal and the TCI states associated with a plurality of associated cells (including the first cell 606 and the second cell 608 maintained by the network node 604).

[0094] The second cell 608 may then send an indication 630 for the UE 602 to activate the first TCI state, and the UE 602 may receive the indication. The sending of the indication 630 may be used to define a time t 0 , which defines a timeline associated with the activation and / or use of the first TCI state. The UE 602 may send a HARQ-ACK 632 at time t 1 , and the second cell 608 may receive the HARQ-ACK at this time. The HARQ-ACK may be processed by the second cell 608 at time t 2 before. In some aspects, the time between t 0 and t 2 represents the minimum delay between the activation of the TCI state and the indication for using the TCI state for communication in a situation where the timing, frequency, and spatial characteristics (e.g., QCL information) associated with the TCI state are known. In some aspects, the time between t 2 and t 3 may represent the periodicity of the RS associated with the first TCI state, while the time between t 3 and t 4 may represent the time for processing the RS. Therefore, the time between t 0 and t 4 represents the maximum (or worst-case) delay before an indication for using the first TCI state can be sent after the indication for activating the first TCI state. In some aspects, the minimum delay represented by the time between t 0 and t 2 may be much smaller (e.g., ~5 ms) than the maximum delay (e.g., ~25 ms) represented by the time between t 0 and t 4 .

[0095] In some aspects, for the first TCI state, network node 604 may identify at 628 that the first TCI state is related to the RS measurements stored by the UE (e.g., the RS indicated in 612). Based on identifying at 628 that the first TCI state is related to the RS measurements stored by the UE, before the next RS 638 associated with the first TCI state is transmitted by the second cell 608, network node 604 may transmit (as early as time t 2 ) an indication 634 for using the first TCI state to communicate with the second cell 608, and UE 602 may receive the indication. Based on the indication 634 for using the first TCI state, the second cell 608 may use the first TCI to transmit a communication 636, and UE 602 may use the first TCI to receive the communication. If the first TCI state is the UL TCI state, UE 602 may use the first TCI to transmit a communication 636, and the second cell 608 may use the first TCI to receive the communication.

[0096] If UE 602 does not maintain RS measurements for a specific activated TCI state, network node 604 may not indicate the use of the specific TCI state until after the next RS associated with the specific TCI state is transmitted by the second cell 608 and received by UE 602. For example, for the second TCI state, the second cell 608 may transmit an indication 640 for activating the second TCI state, and UE 602 may receive the indication. Before or after transmitting the indication 640, network node 604 may identify and / or determine at 628 that the measurements for the RS associated with the second TCI state are not maintained by UE 602. Therefore, the second cell 608 may wait to transmit an indication 644 for using the second TCI state until after transmitting the next RS 642 associated with the second TCI state and waiting for the processing time at UE 602. Once the next RS 642 associated with the second TCI state has been transmitted and the processing time at UE 602 has expired, the second cell 608 may transmit an indication 644 for using the second TCI state to communicate with the second cell 608, and UE 602 may receive the indication. Based on the indication 644 for using the second TCI state, the second cell 608 may use the second TCI state to transmit a communication 646, and UE602 may use the second TCI state to receive the communication.

[0097] Figure 7Call flow diagram 700 illustrates a wireless communication method for reducing latency during a handover of a UE 702 from being served by a first cell 706 to being served by a second cell 708 in a cell group associated with a network node 704, in accordance with some aspects of the present disclosure. In some aspects, the UE 702 may send a UE capability indication 710, and the first cell 706 may receive the UE capability indication. The first cell 706 may be a primary cell for communicating control messages between the UE 702 and a network (or network node) associated with the cell group associated with the network node 704. In some aspects, the UE capability indication 710 may be related to the buffer and / or memory size of the UE for storing RS measurements and / or information. Thus, in some aspects, the UE capability indication 710 indicates the capacity of the UE to store RS measurements. For example, the UE capability indication 710 may indicate (1) the total number of reference signals; or (2) the number of cells for which measurements can be maintained and the number of reference signals per cell, along with an indication of how long the information can be maintained. RS measurement information that exceeds the indicated capacity (e.g., for RS measurements outside the indicated time period or for RS measurements exceeding the indicated total number) may be assumed to be erased in a first-in, first-out (FIFO) manner to capture new RS measurement information. In some aspects, the UE capability indication 710 may be included in an initial (or L3) configuration action set. The network node may then indicate parameters for RS measurement maintenance, such as the number of RS measurements to be maintained and / or the time period for maintaining the RS measurements. In some aspects, the parameters for RS measurement maintenance may be known parameters based on the capacity indicated in the UE capability indication 710.

[0098] In some aspects, the first cell 706 may send an indication 712 of a set of reference signals to be monitored and / or TCI states to be activated, and the UE 702 may receive the indication. In some aspects, the indication 712 may include an indication for maintaining associated RS measurement information and parameters such as the number of RS measurements to be maintained or the time period for holding RS measurements. In some aspects, the indication 712 may be received via a MAC-CE. In some aspects, the activated TCI state is selected from a TCI state pool associated with the serving cell (e.g., the first cell 706). The TCI states in the TCI state pool may be associated with corresponding reference signals, e.g., may be QCLed therewith. In some aspects, the QCL between a TCI state and a corresponding RS may indicate that one or more of the frequency offset, timing offset, or spatial characteristics associated with the corresponding reference signal may be applied to the communication associated with the TCI state. In some aspects, the indication 712 may include a set of reference signals and / or TCI states associated with the second cell 708 and / or additional candidate cells (not shown), the additional candidate cells being associated with a cell group associated with the network node 704. To be able to indicate a reference signal or TCI state associated with the second cell 708, in some aspects, a PCI field may be associated with the TCI states in the TCI state pool or may be used to identify the activated TCI state.

[0099] Based on the indication 712 of the reference signals and / or TCI states to be activated, the UE 702 may measure the set of reference signals indicated in the indication 712 at 722. The set of reference signals measured at 722 may include one or more of a first RS 714 sent by the first cell 706, a second RS 716 sent by the first cell 706, a third RS 718 sent by the second cell 708, and a fourth RS 720 sent by the second cell 708. In some aspects, the set of reference signals measured at 722 may include additional reference signals sent by the first cell 706, the second cell 708, or other cells in the cell group associated with the network node 704, which are not depicted for clarity. The UE 702 may send an RS report 723 indicating the set of reference signals measured by the UE 702 at 722, and the first cell 706 may receive the RS report.

[0100] The first cell 706 may send an indication 724 for the UE 702 to handover from being served by the first cell 706 to being served by the second cell 708, and the UE 702 may receive the indication. Based on the indication 724, the UE 702 may then handover from being served by the first cell 706 to the second cell 708 at 726 while maintaining the RS measurements made while being served by the first cell 706. In some aspects, the network node 704 may identify, at 728, a TCI state associated with, related to, or corresponding to a reference signal in the set of reference signals measured by the UE 702 at 722. At 728, the identification may be based on mapping information regarding the relationship between the reference signal and the TCI states associated with a plurality of associated cells, including the first cell 706 and the second cell 708 maintained by the network node 704.

[0101] In some aspects where a first TCI state associated with the second cell 708 is indicated in the indication 712, the second cell 708 may send an indication 734 for using the first TCI state to communicate with the second cell 708 before the next RS associated with the first TCI state is sent by the second cell 708, and the UE 702 may receive the indication. In some aspects, for the first TCI state, the network node 704 may identify, at 728, that the first TCI state is related to the RS measurements stored by the UE (e.g., the RS indicated in the indication 712). In some aspects, the indication 734 is sent based on identifying at 728 that the first TCI state is related to the RS measurements stored by the UE. Based on the indication 734 for using the first TCI state, the second cell 708 may send a communication 736 using the first TCI, and the UE 702 may receive the communication using the first TCI.

[0102] If the UE 702 does not maintain RS measurements for a specific activated TCI state, the network node 704 may not indicate the use of the specific TCI state until after the next RS associated with that specific TCI state is transmitted by the second cell 708 and received by the UE 702. However, to avoid the latency associated with waiting for the next transmission of the RS associated with a specific TCI state, the second cell 708 may send an indication of an aperiodic (AP) CSI-RS at a time that may be before the next RS transmission associated with the specific TCI state. For example, for the second TCI state, the second cell 708 may send an indication 738 of the AP CSI-RS and an indication 740 for activating the second TCI state, and the UE 702 may receive these indications. The second cell 708 may send the AP CSI-RS 742, and the UE 702 may receive the AP CSI-RS. Based on the AP CSI-RS measurements, the UE 702 may obtain the frequency, timing, and / or spatial characteristics associated with the second TCI state. Once the next AP CSI-RS 742 associated with the second TCI state has been transmitted and the processing time at the UE 702 has expired, the second cell 708 may send an indication 744 for using the second TCI state to communicate with the second cell 708, and the UE 702 may receive the indication. Based on the indication 744 for using the second TCI state, the second cell 708 may send a communication 746 using the second TCI state, and the UE 702 may receive the communication using the second TCI state. By scheduling the AP CSI-RS 742, the second cell 708 may avoid at least a portion of the additional latency between TCI state activation and TCI state use associated with waiting for an RS transmission after TCI state activation.

[0103] Figure 8 FIG. 800 is a diagram illustrating the mapping of reference signals to TCI states associated with different cells. Each cell may be associated with a pool of TCI states that can be activated (e.g., a pool of TCI states 810 associated with the first cell and a pool of TCI states 830 associated with the second cell). For the first active cell, a set of TCI states 820 may be activated by a network node from the pool of TCI states 810. As described above, the set of activated TCI states 820 may include TCI states from the pool of TCI states 830, but are not illustrated for clarity.

[0104] Each TCI state in the set of activated TCI states 820 can be associated with at least one RS (e.g., at least one of SSB_0 to SSB_N or CSI-RS_0 to CSI-RS_M). The network node and / or the UE can maintain an RS-to-TCI state mapping 840. The RS-to-TCI state mapping 840 can indicate the set of TCI states associated with each reference signal in the reference signal set and the cell associated with the TCI state (e.g., using the TCI ID, PCI pair). After the UE switches from being served by a first cell to being served by a second cell, the RS-to-TCI state mapping 840 can be used by the network node to identify and / or determine whether the UE maintains a measurement RS associated with the activated TCI state. The UE can use the RS-to-TCI state mapping 840 to identify RS measurements for deriving information related to the activated TCI state.

[0105] In some aspects, one or more TCI states can be associated with multiple TRPs that may be capable of participating in a Coherent Joint Transmission (CJT) operation in which joint pre-coding can be applied across the TRPs. In some aspects, each TRP can be associated with a TCI state, and certain channels (e.g., PDSCH) can be associated with the CJT operation, e.g., can be CJT-enabled, while other channels (e.g., PDCCH) can have non-coherent transmissions from multiple TRPs. In some aspects, the UE can indicate the capacity to apply more than one TCI state for each channel (e.g., PDSCH-CJT). In some aspects, a UE in a CJT operation can select a single TCI state from multiple TCI states for multiple TRPs to apply to one or more channels associated with the CJT operation. In some aspects, a single TCI state can be signaled to the UE based on an indication that the UE does not have the capacity to apply more than one TCI state for each channel or when the UE is configured to provide a multi-TRP (mTRP) CJT CSI report. In some aspects, the TCI state can be signaled or indicated for each TRP. The UE can select a specific TCI state for each channel from multiple TCI states for each channel (or at least for channels where CJT can be applied, e.g., CJT-enabled channels) based on an implicit indication or an explicit indication. The TCI state can be implicitly indicated by sorting the TCI states associated with multiple TRPs such that the first (or second) TCI state in the sorted list is identified as the unified or joint TCI state for at least CJT-enabled channels (e.g., PDSCH). Alternatively, the explicit indication can be provided by the network node via one or more of RRC signaling, MAC-CE, or DCI. For example, the sTRP / mTRP one-shot handover field can be reused to dynamically indicate which TCI is applied to the PDSCH.

[0106] In some aspects, different types of QCL schemes (e.g., PDSCH-CJT_SchemeA, PDSCH-CJT_SchemeB, PDSCH-CJT_SchemeC, or PDSCH-CJT_SchemeD) can be defined for multiple TCI states applied to the CJT-enabled (or active) channel. As described above, each TRP associated with CJT operation can be associated with a TCI state and can identify a specific QCL scheme to determine what information from each TCI state can be used for the channel (e.g., PDSCH) associated with the CJT operation. For example, schemeA can indicate that all QCL information associated with each state can be used, while schemeB (or schemeC) can indicate ignoring QCL-typeB (or typeC) information for all TCI states except one TCI state associated with multiple TRPs, because coherent transmissions from mTRP should share the timing and frequency characteristics indicated in TypeB and typeC QCL information.

[0107] In some aspects, the mTRP PUSCH can use up to two TCI states and 2 power control (PC) parameter settings. The PUSCH transmission can be scheduled and / or activated by DCI format 01 or 0_2 to follow the spatial domain transmission filter for the associated SRS resource indicated in DCI format 01 or 0_2. The PC parameter associated with the PUSCH can be a PC parameter based on the TCI state associated with the SRS or a PC parameter based on an independent TCI state (e.g., if the corresponding SRI is the first SRI or the second SRI, the PUSCH PC parameter can be associated with the first indicated TCI or the second indicated TCI). Alternatively, one TCI state can be defined as the default TCI state for the PC parameter, for example, based on the corresponding SRI order index. In some aspects, when the TCI state does not include a PC parameter, a default set of PC parameters can be defined and / or provided (e.g., configured in BWP-UplinkDedicated), and the UE can apply a set of default PC parameters based on one of the rules in the rule or based on signaling (e.g., using a bitmap in RRC signaling). For example, the indicated TCI of CORESET pool0 can apply the first default set of PC parameters, the TCI of CORESET pool1 can apply the second default set of PC parameters, or the kth indicator TCI (without specifying a PC parameter) can apply the kth default set of PC parameters.

[0108] In some aspects, system frame number (SFN) alignment or SSB-based measurement timing configuration (SMTC) can be useful when performing inter-cell RS measurements. The UE and / or network node may determine whether to perform SFN alignment or SMTC. Factors for determining whether to perform SFN alignment or SMTC may include the type of DL RS used (e.g., SSB or CSI-RS), whether the DL RS is configured in the serving cell or in the measured candidate cell, the measurement type (e.g., intra-frequency or inter-frequency), and whether the serving cell and the measured candidate cell are synchronized during the training operation for DL transmission (e.g., whether deriveSSB_IndexFromCell is enabled and / or whether the reception timing difference is greater than the time of the CP). In some aspects, SFN alignment may include configuring an sfn offset (e.g., an offset time associated with the system frame number) or an sfn-ssb offset (e.g., an offset time associated with the SSB and the system frame number).

[0109] Figure 9 is a flowchart 900 of a wireless communication method. The method may be performed by a UE (e.g., UE 104, 602, or 702; apparatus 1304). At 906, the UE may receive, from a network node, a first indication (e.g., a handover indication) for the UE to hand over from being served by a first cell to being served by a second cell. For example, 906 may be performed by Figure 13 the application processor 1306, the cellular baseband processor 1324, the transceiver 1322, the antenna 1380, and / or the ITRM component 198. In some aspects, the UE may have previously sent an indication of its ability to support storing measurement information regarding reference signals (e.g., a UE capability indication). The UE may receive an indication to measure at least one reference signal associated with the second cell or an indication to measure a set of reference signals associated with the activated TCI state of the first cell while being served by the first cell. The UE may have additionally received an indication to maintain a specific number of RS measurements or to maintain RS measurements for a specific amount of time (e.g., a time period indication that may be included in a maintenance indication), such as a maintenance indication, based on the indication of its ability to support storing measurement information regarding RS measurements. The UE may also send a report of one or more reference signals measured by the UE. For example, referring Figure 6 and Figure 7 to, UE 602 or 702 may receive indication 624 or 724 and may have previously sent UE capability indication 610 or may have previously received indication 612.

[0110] Before or after the first indication received at 906, the UE may receive a third indication (e.g., TCI state activation indication) for the UE to activate the TCI state associated with the second cell. Based on the indication for the UE to activate the TCI state, at 918, the UE may receive a second indication (e.g., TCI state indication) for the UE to use the TCI state (e.g., the TCI state indication may be preceded by the corresponding TCI state activation indication). For example, 918 may be performed by Figure 13 the application processor 1306, the cellular baseband processor 1324, the transceiver 1322, the antenna 1380, and / or the ITRM component 198. In some aspects, the first time period between the handover indication and the TCI state indication may be based on the relationship between the TCI state and one or more reference signals measured by the UE before receiving the first indication to hand over to the second cell. In some aspects, the minimum delay between receiving the third indication and receiving the second indication at 914 may be based on the relationship between the TCI state and one or more reference signals. In some aspects, the first time period is independent of the time of receiving the reference signal associated with the TCI state after receiving the second indication. In some aspects, the first time period may be based on the report of the measured reference signal. For example, referring to Figure 6 and Figure 7 , the UE 602 or 702 may receive the TCI indication 634 or 734 based on the previous TCI state activation indicated in the indication 630 or 712.

[0111] In some aspects, the UE may maintain mapping information regarding the relationship between the reference signal and the TCI state associated with the second cell. In some aspects, the mapping information regarding the relationship between the reference signal and the TCI state associated with the second cell includes information regarding the quasi - co - location of at least one reference signal and at least one TCI state associated with the second cell. In some aspects, the UE may use the mapping information to determine the first time period.

[0112] At 920, the UE may communicate with the network node via the second cell and using the TCI state. For example, 920 may be performed by Figure 13 the application processor 1306, the cellular baseband processor 1324, the transceiver 1322, the antenna 1380, and / or the ITRM component 198. In some aspects, the communication may be UL communication or DL communication, and the RS may be measured multiple times to evaluate the PL associated with the TCI state and / or may be measured at least once to derive the timing / frequency error for sending / receiving signals and / or the transmit / receive spatial filtering. For example, referring to Figure 6 and Figure 7 , the UE 602 or 702 may send and / or receive the communication 636 and / or 736.

[0113] In some aspects, a UE may receive a fourth indication (second TCI state activation indication) for the UE to activate an additional (or second) TCI state, measure a reference signal associated with the additional TCI state to obtain timing and frequency information of the additional TCI state, and receive a fifth indication (second TCI state indication) for the UE to use the additional TCI state. In some aspects, the fifth indication may be received during a second time period between the second TCI state activation indication and the second TCI state indication, and the second time period may be based on a third timing associated with receiving the reference signal associated with the additional TCI state. In some aspects, the reference signal associated with the additional TCI state is aperiodic, and the UE may receive a sixth indication (e.g., AP RS timing indication) of the third timing of the reference signal associated with the additional TCI state. For example, refer to Figure 6 and Figure 7 , before receiving the indication for using the second TCI state at 644 or 744 and starting to communicate with the second cell using the second TCI state at 646 or 746, the UE 702 may receive an indication 738, and the UE 602 or 702 may receive an indication 640 or 740 for activating the TCI state and measure the next RS 642 or the next AP CSI-RS 742.

[0114] Figure 10 is a flowchart 1000 of a wireless communication method. The method may be performed by a UE (e.g., UE 104, 602, or 702; device 1304). At 1002, the UE may send a UE capability indication that indicates support for the ability to store measurement information of measurements of reference signals at the UE. For example, 1002 may be performed by Figure 13 the application processor 1306, the cellular baseband processor 1324, the transceiver 1322, the antenna 1380, and / or the ITRM component 198. Refer to Figure 6 and Figure 7 , for example, the UE602 or 702 may send a UE capability indication 610 or 710.

[0115] At 1004, when being served by a first cell, the UE may receive an indication for measuring at least one reference signal associated with a second cell. For example, 1004 may be performed by Figure 13Performed by the application processor 1306, cellular baseband processor 1324, transceiver 1322, antenna 1380, and / or ITRM component 198. In some aspects, the indication for measuring at least one reference signal associated with a second cell can, in some aspects, be an indication for measuring a set of reference signals associated with the activated TCI state of a first cell when served by the first cell. The UE can additionally receive an indication for maintaining a specific number of RS measurements or maintaining RS measurements for a specific amount of time (e.g., a time period indication that can be included in the maintenance indication), such as a maintenance indication, based on an indication of the ability to support storing measurement information regarding RS measurements at the UE. Refer to Figure 6 and Figure 7 , for example, UE 602 or 702 can receive indication 612 or 712.

[0116] At 1006, the UE can receive a first indication (e.g., a handover indication) from a network node for the UE to handover from being served by a first cell to being served by a second cell. For example, 1006 can be performed by Figure 13 the application processor 1306, cellular baseband processor 1324, transceiver 1322, antenna 1380, and / or ITRM component 198. The UE can also send a report of one or more reference signals measured by the UE. For example, refer to Figure 6 and Figure 7 , UE 602 or 702 can receive indication 624 or 724.

[0117] Before or after the first indication received at 1006, at 1008, the UE can receive a third indication (e.g., a TCI state activation indication) for the UE to activate a TCI state associated with the second cell. For example, 1008 can be performed by Figure 13 the application processor 1306, cellular baseband processor 1324, transceiver 1322, antenna 1380, and / or ITRM component 198. For example, refer to Figure 6 and Figure 7 , UE 602 or 702 can receive indication 612 or 712.

[0118] At 1010, the UE can measure a reference signal associated with the activated TCI state (e.g., the TCI state activated by the indication received at 1008) to obtain timing and frequency information of the activated TCI state. In some aspects, the measured reference signal associated with the activated TCI state can be an AP RS, and measuring the reference signal at 1010 can include: receiving, at 1011, an AP RS timing indication of the timing of the reference signal associated with the activated TCI state. For example, 1010 and 1011 can be performed by Figure 13performed by the application processor 1306, the cellular baseband processor 1324, the transceiver 1322, the antenna 1380, and / or the ITRM component 198. In some aspects, the activated TCI state may be a TCI state associated with the first cell and / or the second cell. For example, referring to Figure 6 and Figure 7 , the UE 602 or 702 may measure one or more reference signals associated with at least one activated TCI state at 622 or 722, or similarly measure the AP CSI-RS based on the indication 738 of the AP CSI-RS (e.g., the timing of the AP CSI-RS).

[0119] At 1012, the UE may maintain mapping information regarding the relationship between the reference signal and the TCI state associated with the second cell. In some aspects, the mapping information regarding the relationship between the reference signal and the TCI state associated with the second cell includes information regarding the quasi-co-location of at least one reference signal and at least one TCI state associated with the second cell. For example, 1012 may be performed by Figure 13 the application processor 1306, the cellular baseband processor 1324, and / or the ITRM component 198. In some aspects, the mapping may additionally or alternatively include a mapping between one or more TCI states associated with the first cell and one or more TCI states associated with the second cell. Although described herein, information regarding the relationship between the reference signal and the TCI state associated with the second cell may be maintained throughout the operations described in Figure 10 . For example, referring to Figures 6 to 8 , the UE 602 or 702 may maintain the RS to TCI state mapping 840.

[0120] At 1014, the UE may maintain measurement information regarding one or more reference signals. For example, 1014 may be performed by Figure 13 the application processor 1306, the cellular baseband processor 1324, and / or the ITRM component 198. In some aspects, the measurement information may be maintained based on a known measurement configuration or a maintenance indication for maintaining measurement information regarding one or more reference signals. In some aspects, the UE may maintain the measurement information for a certain period of time based on one or more of the following: a known period configuration; or a maintenance period indication. For example, referring to Figures 6 to 8 , the UE 602 or 702 may maintain the RS to TCI state mapping 840.

[0121] At 1016, the UE may send a report indicating that one or more reference signals are measured by the UE. For example, 1016 may be performed by Figure 13executed by the application processor 1306, the cellular baseband processor 1324, the transceiver 1322, the antenna 1380, and / or the ITRM component 198. Refer to Figure 7 , for example, the UE 702 may transmit an RS report 723.

[0122] Based on the indication for the UE to activate the TCI state, at 1018, the UE may receive a second indication (e.g., TCI state indication) for the UE to use the TCI state (e.g., the TCI state indication may be preceded by a corresponding TCI state activation indication). For example, 1018 may be Figure 13 executed by the application processor 1306, the cellular baseband processor 1324, the transceiver 1322, the antenna 1380, and / or the ITRM component 198. In some aspects, the first time period between the handover indication and the TCI state indication may be based on the relationship between the TCI state and one or more reference signals measured by the UE before receiving the first indication to handover to the second cell. In some aspects, the minimum delay between receiving the TCI state activation indication and receiving the TCI state indication at 1018 may be based on the relationship between the TCI state and one or more reference signals. In some aspects, the first time period is independent of the time of receiving the reference signal associated with the TCI state after receiving the TCI state indication. In some aspects, the UE may use the mapping information to determine the first time period. In some aspects, the first time period may be based on the report of the measured reference signal transmitted at 1016. For example, refer to Figure 6 and Figure 7 , the UE 602 or 702 may receive the TCI indication 634 or 734 based on the previous TCI state activation indicated in the indication 630 or 712.

[0123] At 1020, the UE may communicate with the network node via the second cell and use the TCI state. For example, 1020 may be Figure 13 executed by the application processor 1306, the cellular baseband processor 1324, the transceiver 1322, the antenna 1380, and / or the ITRM component 198. In some aspects, the communication may be UL communication or DL communication, and the RS may be measured multiple times to evaluate the PL associated with the TCI state and / or may be measured at least once to derive the timing / frequency error for transmitting / receiving signals and / or the transmit / receive spatial filtering. For example, refer to Figure 6 and Figure 7 , the UE 602 or 702 may transmit and / or receive the communication 636 and / or 736.

[0124] In some aspects, the UE may return to 1008 to receive a fourth indication (second TCI state activation indication) for the UE to activate an additional (or second) TCI state, measure a reference signal associated with the additional TCI state to obtain timing and frequency information of the additional TCI state, and receive a fifth indication (second TCI state indication) for the UE to use the additional TCI state. In some aspects, the fifth indication may be received during a second time period between the second TCI state activation indication and the second TCI state indication, and the second time period may be based on a third timing associated with receiving the reference signal associated with the additional TCI state. In some aspects, the reference signal associated with the additional TCI state is an aperiodic reference signal, and the UE may receive a sixth indication (e.g., AP RS timing indication) of the third timing of the reference signal associated with the additional TCI state. For example, refer to Figure 6 and Figure 7 , before receiving the indication to use the second TCI state at 644 or 744 and starting to communicate with the second cell using the second TCI state at 646 or 746, the UE 702 may receive an indication 738, and the UE 602 or 702 may receive an indication 640 or 740 to activate the TCI state and measure the next RS 642 or the next AP CSI-RS 742.

[0125] Figure 11 is a flowchart 1100 of a wireless communication method. The method may be performed by a base station (e.g., base station 102; cell 606, 608, 706, or 708; network entity 1402). At 1114, the base station may instruct the UE to switch from being served by a first cell to being served by a second cell. For example, 1114 may be performed by Figure 14 the CU processor 1412, DU processor 1432, RU processor 1442, transceiver 1446, antenna 1480, and / or ITRC component 199. In some aspects, the instruction may be performed via at least one of MAC-CE or DCI. In some aspects, the base station may have previously received an indication of the ability to support storing measurement information regarding measurements of reference signals at the UE. The base station may send an indication to measure at least one reference signal associated with the second cell or an indication to measure a set of reference signals associated with the activated TCI state of the first cell when being served by the first cell. The base station may have additionally sent an indication to maintain a specific number of RS measurements or maintain RS measurements for a specific amount of time based on the indication of the ability to support storing measurement information regarding RS measurements at the UE. The base station may also receive a report of one or more reference signals measured by the UE. For example, refer to Figure 6 and Figure 7, the network node 604 or 704 (via cell 606 or 608) may send an indication 624 or 724, and may have previously received a UE capability indication 610 or may have previously sent an indication 612.

[0126] Before or after the first indication sent at 1114, the base station may send a third indication for the UE to activate the TCI state associated with the second cell. Based on the indication for the UE to activate the TCI state, at 1116, the base station may instruct the UE to use the TCI state. For example, 1116 may be performed by Figure 14 the CU processor 1412, DU processor 1432, RU processor 1442, transceiver 1446, antenna 1480, and / or ITRC component 199. In some aspects, the indication to use the TCI state may be performed via DCI. In some aspects, based on the relationship between the TCI state and one or more reference signals measured by the UE before receiving the first indication to switch to the second cell, the second indication may be sent at a timing after the first indication. In some aspects, the minimum delay between receiving the third indication and receiving the second indication at 1116 may be based on the relationship between the TCI state and one or more reference signals. In some aspects, the timing is independent of the time to send the reference signal associated with the TCI state after sending the second indication. In some aspects, the timing may be based on the report of the measured reference signal. For example, refer to Figure 6 and Figure 7 , the network node 604 or 704 may send a TCI indication 634 or 734 via the second cell 608 based on the activation of the previous TCI state indicated in the indication 630 or 712.

[0127] In some aspects, the base station may maintain mapping information regarding the relationship between the reference signal and the TCI state associated with the second cell. In some aspects, the mapping information regarding the relationship between the reference signal and the TCI state associated with the second cell includes information about the quasi - co - location of at least one reference signal and at least one TCI state associated with the second cell. In some aspects, the base station may use the mapping information to determine the timing after the first indication.

[0128] At 1118, the UE may communicate with the network node via the second cell and using the TCI state. For example, 1118 may be performed by Figure 14 the CU processor 1412, DU processor 1432, RU processor 1442, transceiver 1446, antenna 1480, and / or ITRC component 199. In some aspects, the communication may be UL communication or DL communication, and the RS may be measured multiple times to evaluate the PL associated with the TCI state and / or may be measured at least once to derive the timing / frequency error for sending / receiving signals and / or the sending / receiving spatial filtering. For example, refer toFigure 6 and Figure 7 ,the network node 604 or 704 may send and / or receive communications 636 and / or 736 via the cell 608 or 708.

[0129] In some aspects, the base station may send a fourth indication for the UE to activate an additional TCI state, measure a reference signal associated with the additional TCI state to obtain timing and frequency information of the additional TCI state, and send a fifth indication for the UE to use the additional TCI state. In some aspects, the fifth indication may be sent at a second timing based on a third timing associated with receiving the reference signal associated with the additional TCI state. In some aspects, the reference signal associated with the additional TCI state is an aperiodic reference signal, and the UE may receive a sixth indication of the third timing of the reference signal associated with the additional TCI state. For example, refer Figure 6 and Figure 7 ,before receiving the indication for using the second TCI state at 644 or 744 and starting to communicate 646 or 746 with the second cell using the second TCI state, the network node 704 may send an indication 738 via the second cell 708, and the network node 704 may send an indication 640 or 740 for activating the TCI state via the second cell 708 and measure the next RS 642 or the next AP CSI-RS 742.

[0130] Figure 12 is a flowchart 1200 of a wireless communication method. The method may be performed by a base station (e.g., base station 102; cell 606, 608, 706 or 708; network entity 1402). At 1202, the base station may receive a UE capability indication that indicates the capability to maintain measurement information regarding measurements of one or more reference signals at the UE. For example, 1202 may be performed by Figure 14 the CU processor 1412, DU processor 1432, RU processor 1442, transceiver 1446, antenna 1480 and / or ITRC component 199. Refer Figure 6 and Figure 7 ,for example, the network node 604 or 704 (via the cell 606 or 608) may receive a UE capability indication 610 or 710.

[0131] At 1204, the base station may indicate to the UE to activate the TCI state via a TCI state activation indication. For example, 1204 may be performed by Figure 14The CU processor 1412, DU processor 1432, RU processor 1442, transceiver 1446, antenna 1480, and / or ITRC component 199 execute. In some aspects, the TCI state activation indication may be for a TCI state associated with a second cell. In some aspects, a TCI state activation indication may be sent to prepare for a potential handover from the current (first) serving cell to the second cell. For example, referring to Figure 6 and Figure 7 , the network node 604 or 704 (via cell 606 or 608) may send an indication 612 or 712 and / or an indication 630 or 740 for the UE to activate the TCI state.

[0132] At 1206, when the UE is served by the first cell, the base station may indicate to the UE to measure at least one reference signal associated with the second cell. For example, 1206 may be executed by Figure 14 the CU processor 1412, DU processor 1432, RU processor 1442, transceiver 1446, antenna 1480, and / or ITRC component 199. In some aspects, the indication to measure at least one reference signal associated with the second cell may, in some aspects, be an indication to measure a set of reference signals associated with the activated TCI state of the first cell and / or the second cell when served by the first cell. In some aspects, the indication for the UE to measure at least one reference signal associated with the second cell may be included (or implied) by the activation of the TCI state indicated at 1204. For example, referring to Figure 6 and Figure 7 , the network node 604 or 704 (via cell 606 or 608) may send an indication 612 or 712.

[0133] Associated with indicating to the UE to measure at least one reference signal at 1206, in some aspects, the base station may additionally indicate to the UE at 1207 to maintain measurement information regarding one or more reference signals measured by the UE before switching to the second cell, and / or indicate at 1208 a maintenance period for the UE to maintain the measurement information. For example, 1207 and / or 1208 may be executed by Figure 14 the CU processor 1412, DU processor 1432, RU processor 1442, transceiver 1446, antenna 1480, and / or ITRC component 199. In some aspects, parameters such as the number of RS measurements to be maintained or the period for holding the RS measurements may be used to indicate the maintenance period. In some aspects, an indication associated with indicating to the UE to measure at least one reference signal associated with the second cell at 1206 may be received via MAC-CE. Referring to Figure 6 and Figure 7, for example, network node 604 or 704 (via cell 606 or 608) may send indication 612 or 712.

[0134] At 1210, the base station may receive a report of one or more reference signals measured by the UE. For example, 1210 may be performed by Figure 14 the CU processor 1412, DU processor 1432, RU processor 1442, transceiver 1446, antenna 1480, and / or ITRC component 199. In some aspects, the report may indicate that measurements have been made (or equivalent measurements have been stored) and / or the report of the measurements (e.g., one or more reported / measured powers). For example, referring to Figure 6 and Figure 7 , network node 604 or 704 (via cell 606 or 608) may receive report 723.

[0135] At 1212, the base station may maintain mapping information regarding the relationship between the reference signal and the TCI state associated with the second cell. In some aspects, the mapping information regarding the relationship between the reference signal and the TCI state associated with the second cell includes information on the quasi - co - location of at least one reference signal and at least one TCI state associated with the second cell. For example, 1212 may be performed by Figure 14 the CU processor 1412, DU processor 1432, RU processor 1442, and / or ITRC component 199. In some aspects, the mapping may additionally or alternatively include a mapping between one or more TCI states associated with the first cell and one or more TCI states associated with the second cell. Although described herein, information regarding the relationship between the reference signal and the TCI state associated with the second cell may be maintained throughout the operations described in Figure 12 . For example, referring to Figures 6 to 8 , network node 604 or 704 may maintain an RS - to - TCI state mapping 840.

[0136] At 1214, the base station may instruct the UE to hand over from being served by the first cell to being served by the second cell. For example, 1214 may be performed by Figure 14 the CU processor 1412, DU processor 1432, RU processor 1442, transceiver 1446, antenna 1480, and / or ITRC component 199. In some aspects, the instruction may be performed via at least one of MAC - CE or DCI. For example, referring to Figure 6 and Figure 7 , network node 604 or 704 (via cell 606 or 608) may send indication 624 or 724.

[0137] At 1216, the base station may instruct the UE to use the TCI state. For example, 1216 may be performed byFigure 14 is performed by the CU processor 1412, DU processor 1432, RU processor 1442, transceiver 1446, antenna 1480, and / or ITRC component 199. In some aspects, the indication for the UE to use the TCI state can be performed via DCI. In some aspects, based on the relationship between the TCI state and one or more reference signals measured by the UE before receiving the indication to switch to the second cell, it can be used for the timing after the indication for the UE to switch from being served by the first cell to being served by the second cell to send the indication. In some aspects, the minimum delay between receiving the third indication and receiving the indication at 1216 can be based on the relationship between the TCI state and one or more reference signals. In some aspects, the timing is independent of the time of sending the reference signal associated with the TCI state after sending the second indication. In some aspects, the timing can be based on the report of the measured reference signal. In some aspects, the base station can use the mapping information maintained at 1212 to determine the timing after the first indication. For example, refer to Figure 6 and Figure 7 , the network node 604 or 704 can send the TCI indication 634 or 734 based on the activation of the previous TCI state indicated in the indication 630 or 712 via the second cell 608.

[0138] At 1218, the UE can communicate with the network node via the second cell and use the TCI state. For example, 1218 can be performed by Figure 14 the CU processor 1412, DU processor 1432, RU processor 1442, transceiver 1446, antenna 1480, and / or ITRC component 199. In some aspects, the communication can be UL communication or DL communication, and the RS can be measured multiple times to evaluate the PL associated with the TCI state and / or can be measured at least once to derive the timing / frequency error for sending / receiving signals and / or the transmit / receive spatial filtering. For example, refer to Figure 6 and Figure 7 , the network node 604 or 704 can send and / or receive the communication 636 and / or 736 via the cell 608 or 708.

[0139] In some aspects, the base station can return to 1204 to indicate (e.g., via the fourth indication) for the UE to activate an additional TCI state, measure the reference signal associated with the additional TCI state to obtain the timing and frequency information of the additional TCI state, and send the fifth indication for the UE to use the additional TCI state. In some aspects, the fifth indication can be sent at the second timing based on the third timing associated with receiving the reference signal associated with the additional TCI state. In some aspects, the reference signal associated with the additional TCI state is an aperiodic reference signal, and the UE can receive the sixth indication of the third timing of the reference signal associated with the additional TCI state. For example, refer toFigure 6 and Figure 7 , before receiving an indication to use a second TCI state at 644 or 744 and starting to communicate with the second cell using the second TCI state at 646 or 746, the network node 704 may send an indication 738 via the second cell 708, and the network node 704 may send an indication 640 or 740 for activating a TCI state via the second cell 708 and measure the next RS 642 or the next AP CSI-RS 742.

[0140] Figure 13FIG. 1300 is a diagram illustrating an example of a hardware implementation for apparatus 1304. Apparatus 1304 may be a UE, a component of a UE, or may implement UE functionality. In some aspects, apparatus 1304 may include at least one cellular baseband processor 1324 (also referred to as a modem) coupled to one or more transceivers 1322 (e.g., cellular RF transceivers). The cellular baseband processor 1324 may include at least one on-chip memory 1324'. In some aspects, apparatus 1304 may also include one or more subscriber identity module (SIM) cards 1320 and at least one application processor 1306 coupled to a secure digital (SD) card 1308 and a screen 1310. The application processor 1306 may include on-chip memory 1306'. In some aspects, apparatus 1304 may also include a Bluetooth module 1312, a WLAN module 1314, an SPS module 1316 (e.g., GNSS module), one or more sensor modules 1318 (e.g., an atmospheric pressure sensor / altimeter; motion sensors such as an inertial measurement unit (IMU), gyroscope, and / or accelerometer; light detection and ranging (LIDAR), radio assisted detection and ranging (RADAR), sound navigation and ranging (SONAR), magnetometer, audio, and / or other technologies for positioning), additional memory modules 1326, a power source 1330, and / or a camera 1332. The Bluetooth module 1312, the WLAN module 1314, and the SPS module 1316 may include on-chip transceivers (TRX) (or in some cases, only receivers (RX)). The Bluetooth module 1312, the WLAN module 1314, and the SPS module 1316 may include their own dedicated antennas and / or communicate using one or more antennas 1380. The cellular baseband processor 1324 communicates with the UE 104 and / or with the RU associated with the network entity 1302 via the transceiver 1322 through one or more antennas 1380. The cellular baseband processor 1324 and the application processor 1306 may each separately include computer-readable media / memory 1324', 1306'. The additional memory module 1326 may also be considered computer-readable media / memory. Each computer-readable media / memory 1324', 1306', 1326 may be non-transitory. The cellular baseband processor 1324 and the application processor 1306 are each responsible for general processing, including the execution of software stored on the computer-readable media / memory. The software, when executed by the cellular baseband processor 1324 / application processor 1306, causes the cellular baseband processor 1324 / application processor 1306 to perform the various functions described above. The computer-readable media / memory may also be used to store data manipulated by the cellular baseband processor 1324 / application processor 1306 when executing the software.The cellular baseband processor 1324 / application processor 1306 can be a component of the UE 350 and can include at least one memory 360 and / or at least one of the TX processor 368, the RX processor 356, and the controller / processor 359. In one configuration, the device 1304 can be at least one processor chip (modem and / or application) and include only the cellular baseband processor 1324 and / or the application processor 1306, while in another configuration, the device 1304 can be the entire UE (e.g., see. Figure 3 the UE 350) and include additional modules of the device 1304.

[0141] As discussed above, the ITRM component 198 is configured to receive, from a network node, a first indication for a UE to handover from being served by a first cell to being served by a second cell. The ITRM component 198 may also be configured to receive a second indication for the UE to use a TCI state, where the second indication is received at a timing after the first indication, based on a relationship between the TCI state and one or more reference signals measured by the UE before receiving the first indication for handover to the second cell. The ITRM component 198 may also be configured to communicate with the network node via the second cell and using the TCI state. The ITRM component 198 may be within the cellular baseband processor 1324, the application processor 1306, or both the cellular baseband processor 1324 and the application processor 1306. The ITRM component 198 may be one or more hardware components specifically configured to perform the processes / algorithms, implemented by one or more processors configured to perform the processes / algorithms, stored in a computer-readable medium for implementation by one or more processors, or some combination of the above. When multiple processors are implemented, the multiple processors may perform the stated processes / algorithms individually or in combination. As shown, the apparatus 1304 may include various components configured for various functions. In one configuration, the apparatus 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) includes means for receiving, from a network node, a first indication for a UE to handover from being served by a first cell to being served by a second cell. The apparatus 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) may include means for receiving a second indication for the UE to use a TCI state. The apparatus 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) may include means for communicating with the network node via the second cell and using the TCI state. The apparatus 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) may include means for receiving a third indication for the UE to activate the TCI state. The apparatus 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) may include means for receiving a fourth indication for the UE to activate an additional TCI state. The apparatus 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) may include means for measuring a reference signal associated with the additional TCI state to obtain timing and frequency information of the additional TCI state. The apparatus 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) may include means for receiving a fifth indication for the UE to use the additional TCI state.The apparatus 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) may include components for receiving a sixth indication of a third timing of a reference signal associated with an additional TCI state. The apparatus 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) may include components for maintaining mapping information regarding the relationship between a reference signal and a TCI state associated with a second cell. The apparatus 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) may include components for maintaining measurement information regarding one or more reference signals based on at least one of: a known measurement configuration; or receiving an indication for maintaining the measurement information. The apparatus 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) may include components for maintaining the measurement information for a certain period of time, the period of time being based on one or more of: a known period configuration; or receiving an indication of the period of time. The apparatus 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) may include components for sending an indication of the ability to support storing measurement information regarding a reference signal at the UE. The apparatus 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) may include components for receiving, when served by a first cell, an indication for measuring at least one reference signal associated with a second cell. The apparatus 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) may include components for sending a third indication that one or more reference signals are measured by the UE, wherein the timing is also based on sending the third indication. The components may be ITRM components 198 of the apparatus 1304 configured to perform the functions described above and recited by the components. As described above, the apparatus 1304 may include a TX processor 368, an RX processor 356, and a controller / processor 359. Thus, in one configuration, the components may be the TX processor 368, the RX processor 356, and / or the controller / processor 359 configured to perform the functions recited by the components or as described regarding Figure 9 and described above. Figure 9 and Figure 10 the functions of the TX processor 368, the RX processor 356, and / or the controller / processor 359.

[0142] Figure 14FIG. 1400 is a diagram illustrating an example of a hardware implementation for network entity 1402. Network entity 1402 may be a BS, a component of a BS, or may implement BS functionality. Network entity 1402 may include at least one of CU 1410, DU 1430, or RU 1440. For example, depending on the layer functionality handled by ITRC component 199, network entity 1402 may include CU 1410; both CU 1410 and DU 1430; each of CU 1410, DU 1430, and RU 1440; DU 1430; both DU 1430 and RU 1440; or RU 1440. CU 1410 may include at least one CU processor 1412. CU processor 1412 may include on-chip memory 1412'. In some aspects, CU 1410 may also include additional memory modules 1414 and communication interface 1418. CU 1410 communicates with DU 1430 via a midhaul link, such as the F1 interface. DU 1430 may include at least one DU processor 1432. DU processor 1432 may include on-chip memory 1432'. In some aspects, DU 1430 may also include additional memory modules 1434 and communication interface 1438. DU 1430 communicates with RU 1440 via a fronthaul link. RU 1440 may include at least one RU processor 1442. RU processor 1442 may include on-chip memory 1442'. In some aspects, RU 1440 may also include additional memory modules 1444, one or more transceivers 1446, one or more antennas 1480, and communication interface 1448. RU 1440 communicates with UE 104. On-chip memories 1412', 1432', 1442' and additional memory modules 1414, 1434, 1444 may each be considered computer-readable media / memory. Each computer-readable media / memory may be non-transitory. Each of processors 1412, 1432, 1442 is responsible for general processing, including executing software stored on the computer-readable media / memory. The software, when executed by the corresponding processor, causes the processor to perform the various functions described above. The computer-readable media / memory may also be used to store data manipulated by the processor when executing the software.

[0143] As discussed above, the ITRC component 199 is configured to instruct the UE to handover from being served by a first cell to being served by a second cell. The ITRC component 199 may also be configured to indicate a TCI state for use by the UE with the second cell, wherein the indication is performed at a timing based on the relationship between the TCI state and one or more reference signals measured by the UE prior to the handover to the second cell. The ITRC component 199 may also be configured to communicate with the UE via the second cell and using the TCI state. The ITRC component 199 may be within one or more processors of one or more of the CU 1410, DU 1430, and RU 1440. The ITRC component 199 may be one or more hardware components specifically configured to perform the processes / algorithms, implemented by one or more processors configured to perform the processes / algorithms, stored in a computer-readable medium for implementation by one or more processors, or some combination of the above. When multiple processors are implemented, the multiple processors may perform the stated processes / algorithms individually or in combination. The network entity 1402 may include various components configured for various functions. In one configuration, the network entity 1402 includes components for instructing the UE to handover from being served by a first cell to being served by a second cell. In some aspects, the network entity 1402 includes components for indicating a transmit configuration indication (TCI) state for use by the UE with the second cell. In some aspects, the network entity 1402 includes components for communicating with the UE via the second cell and using the TCI state. In some aspects, the network entity 1402 includes components for indicating a TCI state activation for use by the UE to activate the TCI state. In some aspects, the network entity 1402 includes components for indicating a second TCI state activation for use by the UE to activate a second TCI state. In some aspects, the network entity 1402 includes components for indicating a second TCI state for use by the UE with the second cell. In some aspects, the network entity 1402 includes components for indicating a third timing of a reference signal associated with the second TCI state. In some aspects, the network entity 1402 includes components for maintaining mapping information regarding the relationship between the reference signal and the TCI state associated with the second cell. In some aspects, the network entity 1402 includes components for instructing the UE to maintain measurement information regarding one or more reference signals measured by the UE prior to the handover to the second cell. In some aspects, the network entity 1402 includes components for indicating a time period for use by the UE to maintain the measurement information. In some aspects, the network entity 1402 includes components for receiving an indication of the ability to maintain measurement information regarding the measurement of the reference signal at the UE. In some aspects, the network entity 1402 includes components for instructing the UE to measure at least one reference signal associated with the second cell when the UE is being served by the first cell.In some aspects, network entity 1402 includes components for receiving reports of measurements of one or more reference signals by the UE, where the timing is also based on receipt of the report. The components can be ITRC components 199 of network entity 1402 configured to perform functions described and documented by the components. As described above, network entity 1402 can include a TX processor 316, an RX processor 370, and a controller / processor 375. Thus, in one configuration, the components can be the TX processor 316, the RX processor 370, and / or the controller / processor 375 configured to perform functions described by the components or as described with respect to Figure 10 and Figure 11 and Figure 12 the functions described.

[0144] In some aspects, during a handover operation, the UE can perform additional beam training and / or management (BM) operations associated with a set of TCI states before communicating via a second cell using a TCI state from the set of TCI states, which is selected from a pool of TCI states associated with the second cell. The set of TCI states can be indicated from a network node (e.g., a base station) via a MAC-CE (or other L2 signaling). In some aspects, the additional BM operations can be based on reference signals received after an indication for activating the set of TCI states. Thus, communication via the second cell can involve additional latency associated with waiting for the next instance of a reference signal associated with the activated TCI state before transmitting an indication for communicating using the TCI state (e.g., via DCI or other L1 signaling). The additional latency can be associated with the periodicity of the associated reference signal (e.g., 20 ms for a Synchronization Signal Block (SSB)). A method and apparatus for reducing latency associated with handover from serving by a first cell to serving by a second cell are provided.

[0145] In some aspects, the method and apparatus can utilize reference signals measured when the UE is served by a first cell (e.g., reference signals measured by the UE before receiving an indication to hand over to a second cell). In some aspects, the method or apparatus can instruct the UE to maintain measurement information regarding one or more reference signals measured when served by the first cell. In some aspects, the method or apparatus can maintain mapping information regarding the relationship between reference signals and TCI states associated with the second cell to identify newly activated TCI states for which reference signals (e.g., CSI-RS or SSB) have been measured, thereby reducing the additional latency introduced by waiting for reference signal transmissions.

[0146] It should be understood that the specific order or hierarchy of the boxes in the disclosed process / flowchart is merely illustrative of the exemplary method. It should be understood that, based on design preferences, the specific order or hierarchy of the boxes in the process / flowchart can be rearranged. Further, some boxes can be combined or omitted. The appended method claims present the elements of the various boxes in a sample order, but are not limited to the specific order or hierarchy presented.

[0147] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Thus, the claims are not limited to the aspects described herein, but are to be accorded the full scope consistent with the language of the claims, and the singular forms of elements are not intended to mean "one and only one" but "one or more" unless specifically stated otherwise. Terms such as "if," "when," and "while" do not imply a direct temporal relationship or reaction. That is, these phrases, such as "when...," do not imply an immediate action in response to or during the occurrence of an action, but simply imply that the action will occur if the condition is met, without requiring a specific or immediate time limit for the occurrence of the action. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or having an advantage over other aspects. Unless specifically stated otherwise, the term "some" means one or more. Combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "any combination of A, B, C, or any of them," including any combination of A, B, and / or C, may include multiple A's, multiple B's, or multiple C's. Specifically, combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "any combination of A, B, C, or any of them" can be only A, only B, only C, A and B, A and C, B and C, or A and B and C, where any such combination may contain one or more members of A, B, or C. A set should be construed as a collection of elements, where the number of elements is one or more. Thus, for a set of X, X will include one or more elements. When at least one processor is configured to perform a set of functions, the at least one processor is configured to perform the set of functions individually or in any combination. Thus, each processor in the at least one processor may be configured to perform a particular subset of the set of functions, where the subset is the complete set, a proper subset of the set, or an empty subset of the set. If a first device receives data from or sends data to a second device, the data may be received / sent directly between the first device and the second device, or indirectly between the first device and the second device through a collection of devices. A device configured to "output" data (such as a transmission, signal, or message) may (e.g.) transmit the data with a transceiver, or may convey the data to a device that transmits the data. A device configured to "obtain" data (such as a transmission, signal, or message) may (e.g.) receive the data with a transceiver, or may obtain the data from a device that receives the data.The information stored in the memory includes instructions and / or data. All structural and functional equivalents of the elements described throughout the aspects of the present disclosure that are known or will later be known to those of ordinary skill in the art are expressly incorporated herein by reference and are covered by the claims. In addition, nothing disclosed herein is intended to be dedicated to the public, whether or not such disclosure is expressly recited in the claims. The words "module", "mechanism", "element", "device", etc. shall not be used as a substitute for the word "component". Accordingly, no claim element shall be construed as a means-plus-function unless the element is expressly recited using the phrase "means for...".

[0148] As used herein, the phrase "based on" should not be construed to refer to a closed set of information, one or more conditions, one or more factors, etc. In other words, the phrase "based on A" (where "A" can be information, a condition, a factor, etc.) should be construed as "at least based on A", unless stated otherwise specifically.

[0149] The following aspects are merely illustrative and can be combined with other aspects or teachings described herein without limitation.

[0150] Aspect 1 is a method for wireless communication at a UE, the method comprising: receiving, from a network node, a handover indication for the UE to hand over from being served by a first cell to being served by a second cell; receiving a TCI state indication that indicates a TCI state for the UE to use with the second cell, wherein a first time period between the handover indication and the TCI state indication is based on a relationship between the TCI state and one or more reference signals measured by the UE before receiving the handover indication; and communicating with the network node via the second cell and using the TCI state.

[0151] Aspect 2 is the method according to aspect 1, wherein time and frequency related information associated with the TCI state for communicating with the network node via the second cell is based on the one or more reference signals measured by the UE.

[0152] Aspect 3 is the method according to any one of aspects 1 and 2, the method further comprising: receiving a TCI state activation indication for the UE to activate the TCI state, wherein the TCI state activation indication is received either before the TCI state indication and either before or after the handover indication, and wherein a minimum delay between the TCI state activation indication and the TCI state indication is based on the relationship between the TCI state and the one or more reference signals.

[0153] Aspect 4 is the method according to aspect 3, wherein the first time period is independent of the time of receiving a reference signal associated with the TCI state after receiving the TCI state indication.

[0154] Aspect 5 is the method according to aspect 4, the method further comprising: receiving a second additional TCI state activation indication for the UE to activate a second additional TCI state; measuring a second additional reference signal associated with the second TCI state to obtain timing and frequency information of the second TCI state; and receiving a second additional TCI state indication for the UE to use the second TCI state with the second cell, wherein a second time period between the second TCI state indication and the second TCI state activation indication is based on a third timing associated with the reference signal associated with the second TCI state.

[0155] Aspect 6 is the method according to aspect 5, wherein the reference signal associated with the additional TCI state is an AP RS, the method further comprising: receiving an AP RS timing indication of the third timing of the reference signal associated with the additional TCI state.

[0156] Aspect 7 is the method according to any one of aspects 1 to 6, the method further comprising: maintaining mapping information about the relationship between a reference signal and a TCI state associated with the second cell.

[0157] Aspect 8 is the method according to aspect 7, wherein the mapping information about the relationship between the reference signal and the TCI state associated with the second cell includes information about quasi - co - location of at least one reference signal and at least one TCI state associated with the second cell.

[0158] Aspect 9 is the method according to any one of aspects 7 or 8, the method further comprising: maintaining measurement information about the one or more reference signals based on at least one of the following: a known measurement configuration; or receiving a maintenance indication for maintaining the measurement information.

[0159] Aspect 10 is the method according to aspect 9, the method further comprising: maintaining the measurement information for a certain time period, the time period being based on one or more of the following: a known time period configuration; or receiving a maintenance time period indication.

[0160] Aspect 11 is the method according to any one of aspects 1 to 10, the method further comprising: sending a UE capability indication, the UE capability indication indicating support for the ability to store measurement information about measurements of reference signals at the UE.

[0161] Aspect 12 is the method according to any one of Aspects 1 to 11, wherein the one or more reference signals are path loss reference signals, and wherein the information related to path loss associated with the TCI state used for communicating with the network node via the second cell is based on the one or more reference signals measured by the UE.

[0162] Aspect 13 is the method according to any one of Aspects 1 to 12, wherein the one or more reference signals include at least one reference signal associated with the second cell, and the method further includes: when served by the first cell, receiving an indication for measuring the at least one reference signal associated with the second cell.

[0163] Aspect 14 is the method according to any one of Aspects 1 to 13, and the method further includes: sending a report indicating that the one or more reference signals are measured by the UE, wherein the first time period is further based on the sending of the report.

[0164] Aspect 15 is a method for wireless communication at a network node, indicating to a UE to switch from being served by a first cell to being served by a second cell via a handover indication; indicating a TCI state for use by the UE with the second cell via a TCI state indication, wherein a first time period between the handover indication and the TCI state indication is based on a relationship between the TCI state and one or more reference signals measured by the UE before performing the handover to the second cell; and communicating with the UE via the second cell and using the TCI state.

[0165] Aspect 16 is the method according to Aspect 15, wherein the handover indication is included in at least one of MAC-CE or DCI.

[0166] Aspect 17 is the method according to any one of Aspects 15 and 16, wherein the TCI state indication is included in DCI.

[0167] Aspect 18 is the method according to any one of Aspects 15 to 17, and the method further includes: indicating to the UE to activate the TCI state via a TCI state activation indication, wherein the TCI state activation indication is in one of a case before the TCI state indication and a case before or after the handover indication, and wherein a minimum delay between the TCI state activation indication and the TCI state indication is based on the relationship between the TCI state and the one or more reference signals.

[0168] Aspect 19 is the method according to aspect 18, wherein the first time period is independent of the time of transmitting the reference signal associated with the TCI state after indicating the activation of the TCI state.

[0169] Aspect 20 is the method according to aspect 19, wherein the TCI state is a first TCI state, and the method further includes: indicating to the UE to activate a second TCI state via a second TCI state activation indication; indicating a second TCI state for the UE to use with the second cell via a second TCI state indication, wherein a second time period between the second TCI state activation indication and the second TCI state indication is based on a third timing associated with the transmission of a second reference signal associated with the second TCI state.

[0170] Aspect 21 is the method according to aspect 20, wherein the reference signal associated with the second TCI state is an aperiodic reference signal, and the method further includes: indicating the third timing of the reference signal associated with the second TCI state.

[0171] Aspect 22 is the method according to any one of aspects 15 to 21, and the method further includes: maintaining mapping information regarding the relationship between the reference signal and the TCI state associated with the second cell.

[0172] Aspect 23 is the method according to aspect 22, wherein the mapping information regarding the relationship between the reference signal and the TCI state associated with the second cell includes information on the quasi - co - location of at least one reference signal and at least one TCI state associated with the second cell.

[0173] Aspect 24 is the method according to any one of aspects 22 or 23, and the method further includes: indicating to the UE to maintain measurement information regarding the one or more reference signals measured by the UE before the handover to the second cell via a maintenance indication.

[0174] Aspect 25 is the method according to aspect 24, and the method further includes: indicating a time period for the UE to maintain the measurement information via a maintenance time period indication.

[0175] Aspect 26 is the method according to aspect 25, and the method further includes: receiving a UE capability indication, the UE capability indication indicating the capability of maintaining the measurement information regarding the measurement of the one or more reference signals at the UE, wherein at least one of the maintenance indication or the maintenance time period indication is based on the UE capability indication.

[0176] Aspect 27 is the method according to any one of aspects 15 to 26, wherein the one or more reference signals are path loss reference signals, and wherein the path loss related information associated with the TCI state used for communicating with the network node via the second cell is based on the one or more reference signals measured by the UE.

[0177] Aspect 28 is the method according to any one of aspects 15 to 27, wherein the one or more reference signals include at least one reference signal associated with the second cell, and the method further includes: when the UE is served by the first cell, instructing the UE to measure the at least one reference signal associated with the second cell.

[0178] Aspect 29 is the method according to any one of aspects 15 to 28, the method further includes: receiving a report of the one or more reference signals measured by the UE, wherein the first time period is further based on the reception of the report.

[0179] Aspect 30 is an apparatus for wireless communication at a device, the apparatus includes a memory and at least one processor, the at least one processor is coupled to the memory, and at least partially based on the information stored in the memory, the at least one processor is configured to implement any one of aspects 1 to 29.

[0180] Aspect 31 is the apparatus according to aspect 30, the apparatus further includes a transceiver or an antenna coupled to the at least one processor.

[0181] Aspect 32 is an apparatus for wireless communication at a device, the apparatus includes components for implementing any one of aspects 1 to 29.

[0182] Aspect 33 is a computer-readable medium (e.g., a non-transitory computer-readable medium) storing computer-executable code, wherein the code, when executed by a processor, causes the processor to implement any one of aspects 1 to 29.

Claims

1. An apparatus for wireless communication at a user equipment (UE), the apparatus comprising: at least one memory; and at least one processor, the at least one processor coupled to the at least one memory, and at least partially based on stored information stored in the at least one memory, the at least one processor is configured, alone or in any combination, to: receive a handover indication from a network node for the UE to hand over from being served by a first cell to being served by a second cell; receive a transmission configuration indication (TCI) state indication that indicates a TCI state for the UE to use with the second cell, wherein a first time period between the handover indication and the TCI state indication is based on a relationship between the TCI state and one or more reference signals measured by the UE before receiving the handover indication; and communicate with the network node via the second cell using the TCI state.

2. The apparatus according to claim 1, wherein time and frequency related information associated with the TCI state for communicating with the network node via the second cell is based on the one or more reference signals measured by the UE.

3. The apparatus according to claim 1, wherein the at least one processor is further configured, alone or in any combination, to: receive a TCI state activation indication for the UE to activate the TCI state, wherein the at least one processor is configured to receive the TCI state activation indication either before the TCI state indication and either before or after the handover indication, and wherein a minimum delay between the TCI state activation indication and the TCI state indication is based on the relationship between the TCI state and the one or more reference signals.

4. The apparatus according to claim 3, wherein the first time period is independent of a time of receiving a reference signal associated with the TCI state after receiving the TCI state indication.

5. The apparatus according to claim 4, wherein the at least one processor is further configured, alone or in any combination, to: receive a second TCI state activation indication for the UE to activate a second TCI state; measure a second reference signal associated with the second TCI state to obtain timing and frequency information of the second TCI state; and receive a second TCI state indication for the UE to use the second TCI state with the second cell, wherein a second time period between the second TCI state indication and the TCI state activation indication is based on a third timing associated with the reference signal associated with the second TCI state.

6. The apparatus according to claim 5, wherein the reference signal associated with the second TCI state is an aperiodic (AP) reference signal (RS), wherein the at least one processor is further configured, alone or in any combination, to: Receive an AP RS timing indication for the third timing of the reference signal associated with the second TCI state.

7. The apparatus according to claim 1, wherein the at least one processor is further configured, alone or in any combination, to: Maintain mapping information regarding the relationship between a reference signal and a TCI state associated with the second cell.

8. The apparatus according to claim 7, wherein the mapping information regarding the relationship between the reference signal and the TCI state associated with the second cell includes information on quasi - co - location of at least one reference signal and at least one TCI state associated with the second cell.

9. The apparatus according to claim 7, wherein the at least one processor is further configured, alone or in any combination, to maintain measurement information regarding the one or more reference signals based on at least one of the following: A known measurement configuration; or A maintenance indication for maintaining the measurement information.

10. The apparatus according to claim 9, wherein the at least one processor is configured, alone or in any combination, to maintain the measurement information for a certain period of time, the period of time being based on one or more of the following: A known period configuration; or A maintenance period indication.

11. The apparatus according to claim 1, wherein the at least one processor is further configured, alone or in any combination, to: Transmit a UE capability indication indicating support for the ability to store measurement information of measurements of a reference signal at the UE.

12. The apparatus according to claim 1, wherein the one or more reference signals are path - loss reference signals, and wherein information related to path - loss associated with the TCI state used for communicating with the network node via the second cell is based on the one or more reference signals measured by the UE.

13. The apparatus according to claim 1, wherein the one or more reference signals include at least one reference signal associated with the second cell, and wherein the at least one processor is further configured, alone or in any combination, to: When served by the first cell, receive an indication for measuring the at least one reference signal associated with the second cell.

14. The apparatus according to claim 1, wherein the at least one processor is further configured, alone or in any combination, to: Transmit a report indicating that the one or more reference signals are measured by the UE, wherein the first period of time is further based on the transmission of the report.

15. An apparatus for wireless communication at a network node, the apparatus comprises: At least one memory; and At least one processor, the at least one processor being coupled to the at least one memory and being configured, at least in part based on stored information stored in the at least one memory, alone or in any combination, to: Indicate, via a handover indication, that a user equipment (UE) performs a handover from being served by a first cell to being served by a second cell; Indicating, via a transmission configuration indication (TCI) state indication, a TCI state for use by the UE with the second cell, wherein a first time period between the handover indication and the TCI state indication is based on a relationship between the TCI state and one or more reference signals measured by the UE before performing the handover to the second cell; and communicating with the UE via the second cell using the TCI state.

16. The apparatus according to claim 15, wherein the at least one processor is further configured, alone or in any combination, to include the handover indication in at least one of a media access control (MAC) control element (MAC-CE) or downlink control information (DCI).

17. The apparatus according to claim 15, wherein the at least one processor is further configured, alone or in any combination, to include the TCI state indication in downlink control information (DCI).

18. The apparatus according to claim 15, wherein the at least one processor is further configured, alone or in any combination, to: indicate, via a TCI state activation indication, that the UE activates the TCI state, wherein the at least one processor is configured, alone or in any combination, to indicate the TCI state activation indication either before the TCI state indication and either before or after the handover indication, and wherein a minimum delay between the TCI state activation indication and the TCI state indication is based on the relationship between the TCI state and the one or more reference signals.

19. The apparatus according to claim 18, wherein the first time period is independent of a time of transmitting a reference signal associated with the TCI state after the TCI state activation indication.

20. The apparatus according to claim 19, wherein the TCI state is a first TCI state, wherein the at least one processor is further configured, alone or in any combination, to: indicate, via a second TCI state activation indication, that the UE activates a second TCI state; and indicate, via a second TCI state indication, the second TCI state for use by the UE with the second cell, wherein a second time period between the second TCI state activation indication and the second TCI state indication is based on a third timing associated with transmission of a second reference signal associated with the second TCI state.

21. The apparatus according to claim 20, wherein the reference signal associated with the second TCI state is an aperiodic reference signal, wherein the at least one processor is further configured, alone or in any combination, to: indicate the third timing of the reference signal associated with the second TCI state.

22. The apparatus according to claim 15, wherein the at least one processor is further configured, alone or in any combination, to: maintain mapping information regarding a relationship between a reference signal and a TCI state associated with the second cell.

23. The apparatus according to claim 22, wherein the mapping information regarding the relationship between the reference signal and the TCI state associated with the second cell includes information on quasi - co - location of at least one reference signal and at least one TCI state associated with the second cell.

24. The apparatus according to claim 22, wherein the at least one processor is further configured, alone or in any combination, to: indicate to the UE to maintain measurement information on the one or more reference signals measured by the UE before the handover to the second cell; and indicate a maintenance period for the UE to maintain the measurement information.

25. The apparatus according to claim 24, wherein the at least one processor is further configured, alone or in any combination, to: receive a UE capability indication that indicates the capability of the UE to maintain the measurement information on the measurement of the one or more reference signals, and at least one of (1) indicating to the UE to maintain the measurement information or (2) indicating the maintenance period based on the UE capability indication.

26. The apparatus according to claim 15, wherein the one or more reference signals are path - loss reference signals, and wherein the information related to path - loss associated with the TCI state used for communicating with the network node via the second cell is based on the one or more reference signals measured by the UE.

27. The apparatus according to claim 15, wherein the one or more reference signals include at least one reference signal associated with the second cell, and wherein the at least one processor is further configured, alone or in any combination, to: indicate to the UE to measure the at least one reference signal associated with the second cell when the UE is served by the first cell.

28. The apparatus according to claim 15, wherein the at least one processor is further configured, alone or in any combination, to: receive a report that the one or more reference signals are measured by the UE, and wherein the first period is further based on the reception of the report.

29. A method for wireless communication at a user equipment (UE), the method comprises: receiving, from a network node, a handover indication for the UE to hand over from being served by a first cell to being served by a second cell; receiving a transmit configuration indication (TCI) state indication that indicates a TCI state for the UE to use with the second cell, wherein a first period between the handover indication and the TCI state indication is based on the relationship between the TCI state and one or more reference signals measured by the UE before receiving the handover indication; and communicating with the network node via the second cell and using the TCI state.

30. A method for wireless communication at a network node, the method comprises: indicating to the UE, via a handover indication, to perform a handover from being served by a first cell to being served by a second cell; Indicating a transmission configuration indication (TCI) state for use by the UE with the second cell, wherein a first time period between the handover indication and the TCI state indication is based on a relationship between the TCI state and one or more reference signals measured by the UE prior to the handover to the second cell; And Communicating with the UE via the second cell and using the TCI state.

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