Ue-based TA updates for candidate cells

Abstract

An apparatus, a method, and a computer program product for wireless communication are provided. One example method may include transmitting capability information to a network entity, the capability information indicating support for UE-based timing advance (TA) updates between a serving cell associated with the network entity and a candidate cell associated with the network entity for Layer 1 (L1) or Layer 2 (L2) mobility. The example method may also include receiving, from the network entity, a configuration for the UE-based TA update. The example method may also include communicating, with the candidate cell, an uplink transmission or a downlink transmission based on the derived TA of the candidate cell and a reception timing difference associated with the serving cell and the candidate cell, the derived TA of the candidate cell being based on the TA of the serving cell.

Description

Technical Field

[0001] This disclosure relates in general to communication systems, and more specifically to wireless communication systems with user equipment (UE)-based advance timing (TA) updates for candidate cells for Layer 1 (L1) or Layer 2 (L2) mobility. Background Technology

[0002] Wireless communication systems are widely deployed to provide a variety of telecommunications services, such as telephone, video, data, messaging, and broadcasting. Typical wireless communication systems employ multiple access technologies that enable 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.

[0003] These multiple access technologies have been adopted in various telecommunications standards to provide a common protocol that enables different wireless devices to communicate at the city, country, region, and even global levels. An example telecommunications standard is 5G New Radio (NR). 5G NR is part of the Continuous Evolution of Mobile Broadband (CEM) program issued by the 3rd Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the Internet of Things (IoT)), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine-type communications (mMTC), and ultra-reliable low-latency communications (URLLC). Some aspects of 5G NR can be based on the 4G Long Term Evolution (LTE) standard. Further improvements to 5G NR technology are needed. These improvements can also be applied to other multiple access technologies and telecommunications standards that adopt these technologies. Summary of the Invention

[0004] The following is a simplified overview of one or more aspects to provide a basic understanding of these aspects. This invention is not a comprehensive overview of all conceived aspects. It neither identifies key or essential 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 descriptions that follow.

[0005] In one aspect of this disclosure, methods, computer-readable media, and apparatus are provided at a user equipment (UE). The apparatus may include: a memory; and at least one processor coupled to the memory. Based at least in part on information stored in the memory, the at least one processor is configured to cause the apparatus to: transmit capability information to a network entity, the capability information indicating support for UE-based TA updates between a serving cell associated with the network entity and a candidate cell associated with the network entity for L1 or L2 mobility. Based at least in part on the information stored in the memory, the at least one processor is configured to cause the apparatus to: receive configuration for the UE-based TA update from the network entity. Based at least in part on the information stored in the memory, the at least one processor is configured to cause the apparatus to: communicate uplink or downlink transmissions using the candidate cell based on a derived TA of the candidate cell and a receive timing difference associated with the serving cell and the candidate cell, the derived TA of the candidate cell being based on the TA of the serving cell.

[0006] In another aspect of this disclosure, methods, computer-readable media, and apparatus at a network entity are provided. The apparatus may include: a memory; and at least one processor coupled to the memory. Based at least in part on information stored in the memory, the at least one processor is configured to cause the apparatus to: obtain capability information associated with a UE, the capability information indicating support for UE-based TA updates between a serving cell associated with the network entity and a candidate cell associated with the network entity for L1 or L2 mobility. Based at least in part on the information stored in the memory, the at least one processor is configured to cause the apparatus to: transmit a configuration for the UE-based TA update for the UE. Based at least in part on the information stored in the memory, the at least one processor is configured to cause the apparatus to: transmit an uplink or downlink transmission via the candidate cell based on a derived TA of the candidate cell and a receive timing difference associated with the serving cell and the candidate cell, the derived TA of the candidate cell being based on the TA of the serving cell.

[0007] To achieve the foregoing and related objectives, one or more aspects include the features fully described below and specifically pointed out in the claims. The following description and drawings illustrate some exemplary features of one or more aspects in detail. However, these features indicate only a few of the various ways in which the principles of the various aspects may be employed. Attached Figure Description

[0008] Figure 1 This is a diagram illustrating an example of a wireless communication system and an access network.

[0009] Figure 2A This is an illustration of an example of the first frame according to various aspects of this disclosure.

[0010] Figure 2B This is a diagram illustrating examples of downlink (DL) channels within a subframe according to various aspects of this disclosure.

[0011] Figure 2C This is an illustration of an example of a second frame according to various aspects of this disclosure.

[0012] Figure 2D This is a diagram illustrating examples of uplink (UL) channels within a subframe according to various aspects of this disclosure.

[0013] Figure 3 This is a diagram illustrating examples of base stations and user equipment (UEs) in an access network.

[0014] Figure 4 This is a diagram illustrating the example of timing advance (TA).

[0015] Figure 5A This is a diagram illustrating example beam management.

[0016] Figure 5B This is a diagram illustrating an example of inter-cell beam management.

[0017] Figure 6 This is a diagram illustrating an example of a UE's mobile and special cell (SpCell) associated handover based on a set of candidate SpCells.

[0018] Figure 7 This is a diagram illustrating the configuration of an example cell.

[0019] Figure 8 This is a diagram illustrating example communication between a network entity and a UE.

[0020] Figure 9 This is a diagram illustrating example reference times and processing times associated with UE-based TA updates.

[0021] Figure 10A This is a diagram illustrating example uplink and downlink timing used in a base station.

[0022] Figure 10B This is a diagram illustrating example uplink and downlink timing for a UE.

[0023] Figure 11 This is a flowchart of a wireless communication method.

[0024] Figure 12 This is a flowchart of a wireless communication method.

[0025] Figure 13 This is a flowchart of a wireless communication method.

[0026] Figure 14 This is a flowchart of a wireless communication method.

[0027] Figure 15 These are illustrations illustrating specific hardware implementations used for example devices and / or network entities.

[0028] Figure 16 This is a diagram illustrating an example of a hardware implementation used for an example network entity. Detailed Implementation

[0029] In some wireless communication systems, UE-based TA updates (also referred to as "UE-based TA measurement" or "UE-based TA acquisition") can be used, where the UE determines the TA based on the Rx timing difference between the current serving cell (also referred to as the "current active serving cell") and candidate cells, and the TA value of the current serving cell. The UE may indicate its capability for UE-based TA updates (e.g., support) in capability information signaled to the network. For a UE indicating support for UE-based TA updates, the network may configure the UE to perform such updates (e.g., by sending configuration for UE-based TA updates). In addition to UE-based TA updates, PDCCH instruction-based TA updates can also be used. PDCCH instructions may include signaling for triggering a random access procedure at the UE. The aspects provided herein enable the provision of timing instances for UE-based TA updates, which facilitates more efficient UE-based TA updates, thereby enabling more efficient wireless communication processing.

[0030] The detailed descriptions described below, in conjunction with the accompanying drawings, are descriptions of various configurations and do not represent the only configurations in which the concepts described herein can be practiced. To provide a thorough understanding of the various concepts, the detailed descriptions include specific details. However, these concepts can be practiced without these specific details. In some cases, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

[0031] Various apparatuses and methods are described below, and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements can be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the system as a whole.

[0032] As an example, an element, or any part of an element, or any combination of elements, may be implemented as a "processing system" comprising one or more processors. 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, system-on-a-chip (SoCs), baseband processors, field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic components, discrete hardware circuitry, and other suitable hardware configured to perform the various functionalities described throughout this disclosure. One or more processors in the processing system can execute software. Whether referred to as software, firmware, middleware, microcode, hardware description language, or other terms, software should be broadly interpreted as instructions, instruction sets, code, code segments, program code, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, or any combination thereof.

[0033] Therefore, in one or more example aspects, specific implementations, and / or use cases, the described functionality may be implemented in hardware, software, or any combination thereof. If implemented in software, the functionality may be stored or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media can be any available medium that can be accessed by a computer. As examples, such computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disc storage devices, magnetic disk storage devices, 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.

[0034] While aspects, implementations, and / or use cases are described herein by way of example, additional or different aspects, implementations, and / or use cases may arise in many different arrangements and scenarios. The aspects, implementations, and / or use cases described herein can be implemented across many different platform types, devices, systems, shapes, sizes, and package arrangements. For example, aspects, implementations, and / or use cases may arise via integrated chip implementations and other devices based on non-modular components (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail / purchasing devices, medical devices, AI-enabled devices, etc.). While some examples may or may not be specific to a use case or application, the described examples may exhibit broad applicability. Aspects, implementations, and / or use cases can range from chip-level or modular components to non-modular, non-chip-level implementations, and further to aggregated, distributed, or original equipment manufacturer (OEM) devices or systems incorporating one or more of the technologies described herein. In some practical settings, devices incorporating the described aspects and features 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 involve 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 can be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, aggregated or decomposed components, end-user equipment, etc., of various sizes, shapes, and configurations.

[0035] The deployment of communication systems such as 5G NR systems can be arranged in a variety of ways using various components or parts. In a 5G NR system or network, network nodes, network entities, network mobility elements, radio access network (RAN) nodes, core network nodes, network elements or network equipment (such as base stations (BS)) or one or more units (or components) performing base station functions can be implemented in aggregated or decomposed architectures. For example, BSs (such as Node B (NB), evolved NB (eNB), NR BS, 5G NB, access point (AP), transmit / receive point (TRP), or cell, etc.) can be implemented as aggregated base stations (also known as standalone BS or monolithic BS) or decomposed base stations.

[0036] Aggregated base stations can be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node. Decentralized base stations 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, the CU may be implemented within a RAN node, and one or more DUs may co-located with the CU, or alternatively, may be geographically or virtually distributed across one or more other RAN nodes. DUs may be implemented to communicate with one or more RUs. Each of the CU, DU, and RU may be implemented as a virtual unit, namely a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU).

[0037] Base station operation or network design can take into account the aggregation characteristics of base station functionality. For example, decomposed base stations can be utilized in Integrated Access Backhaul (IAB) networks, Open Radio Access Networks (O-RAN (such as network configurations advocated by the O-RAN Alliance)), or Virtualized Radio Access Networks (vRAN, also known as Cloud Radio Access Networks (C-RAN)). Decomposition can include distributing functionality across two or more units in various physical locations, as well as virtually distributing the functionality of at least one unit, which enables flexibility in network design. The various units of a decomposed base station or decomposed RAN architecture can be configured to communicate with at least one other unit via wired or wireless communication.

[0038] Figure 1 Figure 100 illustrates an example of a wireless communication system and access network. The illustrated wireless communication system includes a decomposed base station architecture. The decomposed base station architecture may include one or more CUs 110, which may communicate directly with the core network 120 via a backhaul link, or indirectly with the core network 120 via one or more decomposed 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. CUs 110 may communicate with one or more DUs 130 via a corresponding midhaul link (such as an F1 interface). DUs 130 may communicate with one or more RUs 140 via a corresponding fronthaul link. RUs 140 may communicate with a corresponding UE 104 via one or more radio frequency (RF) access links. In some implementations, a UE 104 may be served simultaneously by multiple RUs 140.

[0039] Each of the units (i.e., CU 110, DU 130, RU 140, and near-RT RIC 125, non-RT RIC 115, and SMO frame 105) may include or be coupled to one or more interfaces configured to receive or transmit signals, data, or information (collectively, signals) via wired or wireless transmission media. Each of the units, or an associated processor or controller providing instructions to the communication interfaces of these units, may be configured to communicate with one or more other units via transmission media. For example, these units may include wired interfaces configured to receive signals or transmit signals to one or more other units via wired transmission media. Additionally, these units may include wireless interfaces that may include receivers, transmitters, or transceivers (such as RF transceivers) configured to receive and / or transmit signals to one or more other units via wireless transmission media.

[0040] In some aspects, the CU 110 can host one or more higher-level control functions. Such control functions may include Radio Resource Control (RRC), Packet Data Convergence Protocol (PDCP), Serving Data Adaptation Protocol (SDAP), etc. Each control function can be implemented using an interface configured to signal to other control functions hosted by the CU 110. The CU 110 can 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 specific implementations, the CU 110 can be logically divided 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 can communicate bidirectionally with the CU-CP units via an interface such as an E1 interface. The CU 110 can be implemented to communicate with the DU 130 for network control and signaling purposes, as needed.

[0041] DU 130 may correspond to a logic unit that includes one or more base station functions for controlling the operation of one or more RU 140s. In some aspects, DU 130 may host one or more of the Radio Link Control (RLC) layer, the Media 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, or demodulation) according to functional splits (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 be implemented using an interface configured to communicate signals with other layers (and modules) hosted by DU 130 or with control functions hosted by CU 110.

[0042] Lower-layer functionality can be implemented by one or more RU 140s. In some deployments, an RU140 controlled by a DU 130 may correspond to a logical node that hosts 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, or both) based on functional decomposition (such as lower-layer functional decomposition). In such architectures, the RU 140 may be implemented to handle over-the-air (OTA) communications with one or more UEs 104. In some specific implementations, the real-time and non-real-time aspects of control plane and user plane communications with the RU140 may be controlled by the corresponding DU 130. In some scenarios, this configuration enables the implementation of the DU 130 and CU 110 in cloud-based RAN architectures (such as vRAN architectures).

[0043] SMO framework 105 can be configured to support RAN deployment and provisioning of both non-virtualized and virtualized network elements. For non-virtualized network elements, SMO framework 105 can be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which can be managed via operation and maintenance interfaces such as the O1 interface. For virtualized network elements, SMO framework 105 can be configured to interact with a cloud computing platform such as 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 may include, but are not limited to, CU 110, DU 130, RU 140, and near-RT RIC 125. In some implementations, SMO framework 105 can communicate with the hardware aspects of the 4G RAN (such as Open eNB (O-eNB) 111) via the O1 interface. Additionally, in some implementations, SMO framework 105 can communicate directly with one or more RU 140s via the O1 interface. SMO framework 105 may also include a non-RT RIC 115 configured to support the functionality of SMO framework 105.

[0044] The non-RT RIC 115 can be configured to include logical functions enabling non-real-time control and optimization of RAN elements and resources, including artificial intelligence (AI) / machine learning (ML) workflows for model training and updates, or policy-based guidance for 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 an A1 interface. The near-RT RIC 125 can be configured to include logical functions enabling near real-time control and optimization of RAN elements and resources via an interface (such as via an E2 interface) through data collection and action, connecting one or more CU 110s, one or more DU 130s, or both, and O-eNBs to the near-RT RIC 125.

[0045] In some implementations, to generate AI / ML models to be deployed in the near-RT RIC 125, the non-RT RIC 115 may receive parameters or external enrichment information from an external server. This information can be utilized by the near-RT RIC 125 and can be received from non-network data sources or 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 may be configured to tune RAN behavior or performance. For example, the non-RT RIC 115 may monitor long-term trends and patterns in performance and employ AI / ML models to perform corrective actions via the SMO framework 105 (such as reconfiguration via O1) or via the creation of RAN management policies (such as A1 policies).

[0046] At least one of CU 110, DU 130, and RU 140 may be referred to as base station 102. Therefore, 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 UE 104 with an access point to core network 120. Base station 102 may include macro cells (high-power cellular base stations) and / or small cells (low-power cellular base stations). Small cells include femtocells, picocells, and microcells. A network that includes both small cells and macro cells may be referred to as a heterogeneous network. A heterogeneous network may also include evolved home node B (eNB) (HeNB), which can provide service to a restricted group referred to as a closed subscriber group (CSG). The communication link between RU 140 and UE 104 may include uplink (UL) transmission (also known as reverse link) from UE 104 to RU 140 and / or downlink (DL) transmission (also known as forward link) transmission from RU 140 to UE 104. The communication link may utilize multiple-input multiple-output (MIMO) antenna techniques, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link may use one or more carriers. For each carrier allocated in 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., 5MHz, 10MHz, 15MHz, 20MHz, 100MHz, 400MHz, etc.). These carriers may or may not be adjacent to each other. Carrier allocation may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated to DL compared to UL). Component carriers may include primary component carriers and one or more secondary component carriers. The primary component carrier can be referred to as the primary cell (PCell), and the secondary component carrier can be referred to as the secondary cell (SCell).

[0047] Some UEs 104 may communicate with each other using device-to-device (D2D) communication link 158. 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 Physical Sidelink Broadcast Channel (PSBCH), Physical Sidelink Discovery Channel (PSDCH), Physical Sidelink Shared Channel (PSSCH), and Physical Sidelink Control Channel (PSCCH). D2D communication may be conducted through various wireless D2D communication systems, such as Bluetooth, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

[0048] The wireless communication system may also include a Wi-Fi AP 150, which communicates with the UE 104 (also referred to as a Wi-Fi station (STA)) via a communication link 154, for example, in an unlicensed spectrum such as 5 GHz. When communicating in unlicensed spectrum, the UE 104 / AP 150 may perform a free channel assessment (CCA) to determine whether the channel is available before communication.

[0049] The electromagnetic spectrum is typically subdivided into various categories, bands, channels, etc., based on frequency / wavelength. In 5G NR, two initial operating bands have been designated as frequency ranges FR1 (410MHz-7.125GHz) and FR2 (24.25GHz-52.6GHz). Although a portion of FR1 is greater than 6GHz, it is often (interchangeably) referred to as the "sub-6GHz" band in various documents and articles. Similar naming issues sometimes occur with FR2, which is often (interchangeably) referred to as the "millimeter wave" band in documents and articles, although this is distinct from the Extremely High Frequency (EHF) band (30GHz-300GHz) designated as "millimeter wave" by the International Telecommunication Union (ITU).

[0050] The frequencies between FR1 and FR2 are generally referred to as intermediate frequency (IF) bands. Recent 5G NR studies have designated the operating bands for these IF bands as the frequency range designation FR3 (7.125GHz-24.25GHz). Bands falling within FR3 can inherit FR1 and / or FR2 characteristics, thus effectively extending the features of FR1 and / or FR2 to IF band frequencies. Furthermore, higher frequency bands are currently being explored to extend 5G NR operation beyond 52.6GHz. For example, three higher operating bands have been designated as the frequency range designations FR2.2 (52.6GHz-71GHz), FR4 (71GHz-114.25GHz), and FR5 (114.25GHz-300GHz). Each of these higher frequency bands falls within the EHF band.

[0051] In view of the above, unless otherwise specified, the use of the term "below 6 GHz" or similar terms herein can broadly refer to frequencies less than 6 GHz, within FR1, or including intermediate frequency band frequencies. Furthermore, unless otherwise specified, the use of the term "millimeter wave" or similar terms herein can broadly refer to frequencies that can include intermediate frequency band frequencies, within FR2, FR4, FR2-2 and / or FR5, or within the EHF band.

[0052] 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 signals 182 to UE 104 in one or more transmit directions. UE 104 may receive beamformed signals from base station 102 in one or more receive directions. UE 104 may also transmit beamformed signals 184 to base station 102 in one or more transmit directions. Base station 102 may receive beamformed signals from UE 104 in one or more receive directions. Base station 102 / UE 104 may perform beamforming training to determine the optimal receive and transmit directions for each of base station 102 / UE 104. The transmit and receive directions of base station 102 may be the same or different. The transmit and receive directions of UE 104 may be the same or different.

[0053] Base station 102 may include and / or be referred to as gNB, Node B, eNB, access point, base transceiver, 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 terminology. Base station 102 may be implemented as an integrated access and backhaul (IAB) node, relay node, sidelink node, aggregated (monolithic) base station with baseband units (BBU) (including CU and DU) and RU, or may be implemented as a decomposed base station including one or more of CU, DU, and / or RU.

[0054] The core network 120 may include Access and Mobility Management Function (AMF) 161, Session Management Function (SMF) 162, User Plane Function (UPF) 163, Unified Data Management (UDM) 164, one or more location servers 168, and other functional entities. AMF 161 is the control node that processes signaling between UE 104 and the core network 120. AMF 161 supports registration management, connection management, mobility management, and other functions. SMF 162 supports session management and other functions. UPF 163 supports packet routing, packet forwarding, and other functions. UDM 164 supports authentication and key agreement (AKA) credential generation, user identity processing, access authorization, and subscription management. One or more location servers 168 are exemplified as including Gateway Mobile Location Center (GMLC) 165 and Location Management Function (LMF) 166. However, generally, one or more location servers 168 may include one or more location / positioning servers, which may include one or more of GMLC 165, LMF 166, a location determination entity (PDE), a serving mobile location center (SMLC), a mobile location center (MPC), etc. GMLC 165 and LMF 166 support UE location services. GMLC 165 provides an interface for clients / applications (e.g., emergency services) to access UE location information. LMF 166 receives measurement and auxiliary information from NG-RAN and UE 104 via AMF 161 to calculate the location of UE 104. NG-RAN may use one or more positioning methods to determine the location of UE 104. Positioning UE 104 may involve signal measurement, location estimation, and optional speed calculation based on these measurements. Signal measurement may be performed by UE 104 and / or serving base station 102. The measured signals may be based on one or more of the following systems / signals / sensors: Satellite Positioning System (SPS) 170 (e.g., one or more of Global Navigation Satellite System (GNSS), Global Positioning System (GPS), Non-Terrestrial Network (NTN) or other satellite positioning / location systems), LTE signals, Wireless Local Area Network (WLAN) signals, Bluetooth signals, Terrestrial Beacon System (TBS), sensor-based information (e.g., barometric pressure sensor, motion sensor), NR Enhanced Cell ID (NR E-CID) method, NR signals (e.g., multiple round-trip time (multiple RTT), DL departure angle (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 other systems / signals / sensors.

[0055] Examples of UE 104 include cellular phones, smartphones, Session Initiation Protocol (SIP) phones, laptops, personal digital assistants (PDAs), satellite radios, GPS devices, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, tablets, smart devices, wearable devices, vehicles, electricity meters, air pumps, large or small kitchen appliances, healthcare devices, implants, sensors / actuators, displays, or any other similarly functional device. Some UEs in UE 104 may be referred to as IoT devices (e.g., parking timers, air pumps, toasters, vehicles, heart monitors, etc.). 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, mobile phone, user agent, mobile client, client, or some other suitable term. In some scenarios, the term UE may also be used for one or more companion devices, such as in a device constellation arrangement. One or more of these devices can access the network together and / or individually.

[0056] Refer again Figure 1 In some aspects, UE 104 may include a TA component 198. In some aspects, TA component 198 may be configured to send capability information to a network entity indicating support for UE-based TA updates between a serving cell associated with the network entity and a candidate cell associated with the network entity for L1 or L2 mobility. In some aspects, TA component 198 may be further configured to receive configuration for UE-based TA updates from the network entity. In some aspects, TA component 198 may be further configured to utilize the candidate cell to convey uplink or downlink transmissions based on the candidate cell's derived TA and a receive timing difference associated with the serving cell and the candidate cell, the derived TA of the candidate cell being based on the serving cell's TA.

[0057] In some aspects, base station 102 may include TA component 199. In some aspects, TA component 199 may be configured to obtain capability information associated with a UE, indicating support for UE-based TA updates between a serving cell associated with a network entity and a candidate cell associated with a network entity for L1 or L2 mobility. In some aspects, TA component 199 may be further configured to transmit configuration for UE-based TA updates to the UE. In some aspects, TA component 199 may be further configured to transmit uplink or downlink transmissions via a candidate cell based on a derived TA of the candidate cell and a receive timing difference associated with the serving cell and the candidate cell, the derived TA of the candidate cell being based on the TA of the serving cell.

[0058] While the following description may focus on 5G NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0059] As described herein, a node (which may be referred to as a node, network node, network entity, or wireless node) may include, may be included in, or may be a component of: a base station (e.g., any base station described herein), a UE (e.g., any UE described herein), a network controller, apparatus, device, computing system, integrated access and backhaul (IAB) node, distributed unit (DU), central unit (CU), remote / radio unit (RU) (which may also be referred to as a remote radio unit (RRU)), and / or another processing entity configured to perform any of the techniques described herein. For example, a network node may be a UE. As another example, a network node may be a base station or a network entity. As yet another example, a first network node may be configured to communicate with a second or third network node. In one aspect of this example, the first network node may be a UE, the second network node may be a base station, and the third network node may be a UE. In another aspect of this example, the first network node may be a UE, the second network node may be a base station, and the third network node may be a base station. In yet another aspect of this example, the first network node, the second network node, and the third network node may be different from these examples. Similarly, references to UE, base station, device, equipment, computing system, etc., may include disclosures of UE, base station, device, equipment, computing system, etc., as network nodes. For example, a disclosure of a UE being configured to receive information from a base station also discloses that a first network node is configured to receive information from a second network node. Consistent with this disclosure, once a particular example is extended according to this disclosure (e.g., a disclosure of a UE being configured to receive information from a base station also discloses that a first network node is configured to receive information from a second network node), a broader example of a narrower example may be interpreted in reverse, but in a broad, open-ended manner. In the above example where a UE is configured to receive information from a base station and a first network node is configured to receive information from a second network node, the first network node may refer to a first UE, a first base station, a first device, a first equipment, a first computing system, a first set of one or more components, or a first processing entity, etc., configured to receive information; and the second network node may refer to a second UE, a second base station, a second device, a second equipment, a second computing system, a second set of one or more components, or a second processing entity, etc.

[0060] As described herein, different terms may be used in various contexts to describe the transmission of information (e.g., any information, signal, etc.). Disclosure of one communication term includes disclosure of other communication terms. For example, a first network node may be described as being configured to send information to a second network node. In this example and consistent with this disclosure, disclosure that a first network node is configured to send information to a second network node includes disclosure that the first network node is configured to provide, transmit, output, communicate, or send information to the second network node. Similarly, in this example and consistent with this disclosure, disclosure that a first network node is configured to send information to a second network node includes disclosure that the second network node is configured to receive, obtain, or decode information provided, transmitted, output, communicate, or sent by the first network node.

[0061] Figure 2A Figure 200 illustrates an example of the first subframe within a 5G NR frame structure. Figure 2B Figure 230 illustrates an example of a DL channel within a 5G NR subframe. Figure 2C Figure 250 illustrates an example of the second subframe within a 5G NR frame structure. Figure 2D Figure 280 illustrates an example of a UL channel within a 5G NR subframe. The 5G NR frame structure can be Frequency Division Duplex (FDD) (where subframes within a specific set of subcarriers (carrier system bandwidth) are dedicated to either DL or UL) or Time Division Duplex (TDD) (where subframes within a specific set of subcarriers (carrier system bandwidth) are dedicated to both DL and UL). Figure 2A , Figure 2C In the provided example, the 5G NR frame structure is assumed to be TDD, where subframe 4 is configured with slot format 28 (most of which are DL), where D is DL, U is UL, and F is flexible and can be used between DL / UL, and subframe 3 is configured with slot format 1 (all of which are UL). Although subframes 3 and 4 are shown as having slot formats 1 and 28 respectively, any particular subframe can be configured with any of the various available slot formats 0-61. Slot formats 0 and 1 are all DL and all UL, respectively. Other slot formats 2-61 include a mixture of DL, UL, and flexible symbols. The UE is configured using the slot format via the received Slot Format Indicator (SFI) (dynamically configured via DL Control Information (DCI) or semi-statically / statically configured via Radio Resource Control (RRC) signaling).

[0062] Figures 2A to 2DThe frame structure is illustrated, and aspects of this disclosure are applicable to other wireless communication technologies that may have different frame structures and / or different channels. A frame (10 ms) can be divided into 10 equally sized subframes (1 ms). Each subframe may include one or more time slots. Subframes may also include mini-time 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. Symbols on the DL can be CP Orthogonal Frequency Division Multiplexing (OFDM) (CP-OFDM) symbols. Symbols on the UL can be CP-OFDM symbols (for high-throughput scenarios) or Discrete Fourier Transform (DFT) Extended OFDM (DFT-s-OFDM) symbols (also known as Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols) (for power-constrained scenarios; limited to single-stream transmission). The number of time slots within a subframe is based on the CP and parameter set. The parameter set defines the subcarrier spacing (SCS) and effectively defines the symbol length / duration, which is equal to 1 / SCS.

[0063]

[0064] Table 1: Parameter Set, SCS, and CP

[0065] For a normal CP (14 symbols / slot), different parameter sets μ 0 to 4 allow 1, 2, 4, 8, and 16 slots per subframe, respectively. For an extended CP, parameter set 2 allows 4 slots per subframe. Therefore, for a normal CP and parameter set μ, there are 14 symbols / slots and 2μ slots / subframes. The subcarrier spacing can be equal to 2μ * 15kHz, where μ is from parameter set 0 to 4. Therefore, the subcarrier spacing is 15kHz for parameter set μ = 0, and 240kHz for parameter set μ = 4. The symbol length / duration is negatively correlated with the subcarrier spacing. Figures 2A to 2D Examples are provided for a normal CP with 14 symbols per time slot and a parameter set μ=2 with 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 the frame set, there may be one or more different bandwidth portions (BWPs) of frequency division multiplexing (see [link to relevant documentation]). Figure 2B Each BWP can have a specific set of parameters and CP (normal or extended).

[0066] A resource grid can be used to represent the frame structure. Each time slot consists of a resource block (RB) extending for 12 consecutive subcarriers (also known as a physical RB (PRB)). The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0067] like Figure 2A As illustrated, some of the REs carry reference (pilot) signals (RS) for the UE. RS may include demodulation RS (DM-RS) (indicated 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. RS may also include beam measurement RS (BRS), beam refinement RS (BRRS), and phase tracking RS (PT-RS).

[0068] Figure 2B Examples of various DL channels within a subframe of a frame are illustrated. The Physical Downlink Control Channel (PDCCH) carries the DCI within one or more Control Channel Elements (CCEs) (e.g., 1, 2, 4, 8, or 16 CCEs), each CCE comprising six RE Groups (REGs), each REG comprising 12 consecutive REs in the OFDM symbols of an RB. A PDCCH within a BWP may be referred to as a Control Resource Set (CORESET). The UE is configured to monitor PDCCH candidates in a PDCCH search space (e.g., a common search space, a UE-specific search space) during PDCCH monitoring timing 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 in the channel bandwidth. The Primary Synchronization Signal (PSS) may be located within symbol 2 of a specific subframe of the frame. The PSS is used by the UE 104 to determine subframe / symbol timing and physical layer identification. The Secondary Synchronization Signal (SSS) may be located within symbol 4 of a specific subframe of the frame. The SSS is used by the UE to determine the Physical Layer Cell Identifier Group Number and radio frame timing. Based on the Physical Layer Identifier and the Physical Layer Cell Identifier Group Number, the UE can determine the Physical Cell Identifier (PCI). Based on the PCI, the UE can determine the location of the DM-RS. The Physical Broadcast Channel (PBCH), carrying the Master Information Block (MIB), can be logically grouped with the PSS and SSS to form a Synchronization Signal (SS) / PBCH block (also known as an SS block (SSB)). The MIB provides the System Frame Number (SFN) and the number of Restricted Blocks (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.

[0069] like Figure 2CAs illustrated, some REs in the REs carry DM-RS (indicated as R for one particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE can transmit DM-RS for the Physical Uplink Control Channel (PUCCH) and the Physical Uplink Shared Channel (PUSCH). The PUSCH DM-RS can be transmitted in the first or second symbol of the PUSCH. Depending on whether a short or 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 a subframe. The SRS can have a comb structure, and the UE can transmit the SRS on one of the comb structures within that comb structure. The SRS can be used by the base station for channel quality estimation to enable frequency-dependent scheduling of the UL.

[0070] Figure 2D Examples of various UL channels within a subframe of a frame are illustrated. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicators (CQI), pre-decoding matrix indicators (PMI), rank indicators (RI), and hybrid automatic repeat request (HARQ) acknowledgment (ACK) feedback (i.e., one or more HARQ ACK bits indicating one or more ACKs and / or negative ACKs (NACKs)). The PUCCH carries data and may additionally be used to carry buffer status reports (BSR), power clearance reports (PHR), and / or UCIs.

[0071] Figure 3This is a block diagram illustrating communication between base station 310 and UE 350 in the access network. In the DL (Data Link Module), Internet Protocol (IP) packets can be provided to controller / processor 375. 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, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, and Media Access Control (MAC) layer. The controller / processor 375 provides RRC layer functionality associated with broadcasting 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 upper-layer packet data unit (PDU) delivery, error correction via ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs), resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with 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 priority ordering.

[0072] Transmit (TX) processor 316 and 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) decoding / decoding of the transport channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. TX processor 316 processes the mapping to the signal constellation based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-order phase shift keying (M-PSK), M-order quadrature amplitude modulation (M-QAM)). The decoded and modulated symbols can then be divided into parallel streams. Each stream can then be mapped to OFDM subcarriers, multiplexed with a reference signal (e.g., a pilot) in the time and / or frequency domains, and then combined using inverse fast Fourier transform (IFFT) to produce a physical channel carrying a stream of time-domain OFDM symbols. The OFDM stream is spatially pre-decoded to generate multiple spatial streams. Channel estimates from channel estimator 374 are used to determine the decoding and modulation scheme, as well as for spatial processing. Channel estimates can be derived from reference signals and / or channel condition feedback transmitted by UE 350. Each spatial stream can then be provided to a different antenna 320 via a separate transmitter 318Tx. Each transmitter 318Tx can use the corresponding spatial stream to modulate a radio frequency (RF) carrier for transmission.

[0073] At 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 that information to the receive (RX) processor 356. The TX processor 368 and RX processor 356 implement Layer 1 functionality associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial stream destined for UE 350. If multiple spatial streams are destined for UE 350, they can 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 transform the OFDM symbol stream from the time domain to the frequency domain. The frequency domain signal consists of a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, along with the reference signal, are recovered and demodulated by determining the most probable signal constellation points transmitted by base station 310. These soft decisions can be based on channel estimates calculated by channel estimator 358. The soft decision is then decoded and deinterleaved to recover the data and control signals originally transmitted by base station 310 on the physical channel. The data and control signals are then provided to controller / processor 359, which implements layer 3 and layer 2 functionality.

[0074] The controller / processor 359 may be associated with a memory 360 that stores program code and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller / processor 359 provides demultiplexing, packet reassembly, decryption, header decompression, and control signal processing between transport and logical channels to recover IP packets. The controller / processor 359 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operation.

[0075] Similar to the functionality described in conjunction with DL transmission performed by base station 310, controller / processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIB) acquisition, RRC connectivity, and measurement reporting; PDCP layer functionality associated with header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functionality associated with upper-layer PDU delivery, error correction via ARQ, concatenation, segmentation, and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs to TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel priority ordering.

[0076] The channel estimate derived by the channel estimator 358 from the reference signal or feedback transmitted by the base station 310 can be used by the TX processor 368 to select an appropriate decoding and modulation scheme and facilitate spatial processing. The spatial stream generated by the TX processor 368 can be provided to different antennas 352 via individual transmitters 354Tx. Each transmitter 354Tx can use the corresponding spatial stream to modulate an RF carrier for transmission.

[0077] UL transmission is processed at base station 310 in a manner similar to that described in conjunction with the receiver function at 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 that information to RX processor 370.

[0078] The controller / processor 375 may be associated with a memory 376 that stores program code and data. The memory 376 may be referred to as a computer-readable medium. In UL, the controller / processor 375 provides demultiplexing, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets between transport and logical channels. The controller / processor 375 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operation.

[0079] At least one of the TX processor 368, RX processor 356, and controller / processor 359 can be configured to combine Figure 1 The TA component 198 is used to perform various aspects.

[0080] At least one of the TX processor 316, RX processor 370, and controller / processor 375 can be configured to combine Figure 1 The TA component 199 is used to perform various aspects.

[0081] The UE may transmit a UL signal to a base station or TRP. The UL signal may take a period of time to reach its destination base station or TRP because the signal may travel from the UE to the destination base station or TRP over a period of time. Therefore, in order to meet the arrival time defined in the wireless communication system (e.g., based on a time slot or other unit definition), the UE in the wireless communication system may transmit the UL signal based on the TA. As an example, the UE may transmit the UL signal based on a period of time before the defined arrival time of the TA (e.g., to compensate for delays caused by the distance between the UE and the TRP). Figure 4 This is an example illustration of timing advance (TA) diagram 400. For example... Figure 4 As illustrated, DL frame 452 of frame number i and its associated UL frame 454 of frame number i can be transmitted on the RF carrier. UL frame 454 of frame number i may begin TA 456 before DL frame 452 of frame number i, where TA may be equal to (N... TA +N TA,offset )T c Parameter T c It can represent a basic unit of time, such as a period (e.g., approximately 3.69 microseconds). Parameter N TA,offset It can represent a frequency band-based TA. Parameter N TA It can represent a TA that can be defined or signaled based on the location of the UE and TRP or base station.

[0082] As an example, in some wireless communication systems, the TA can be a value between 0 and 63, where each step between 0 and 63 represents an advance of one period (e.g., approximately 3.69 microseconds). In the case where the signal (radio wave) travels at approximately 300,000,000 meters per second (i.e., 300 meters per microsecond), one TA step represents a change of approximately 1,100 meters in the round-trip distance (twice the propagation range). Therefore, in such an example, the TA could change for every 550 meters of change in the distance between the UE and the TRP / base station.

[0083] A TAG may include one or more serving cells that share the same uplink TA and the same downlink timing reference cell. Each TAG may be associated with at least one serving cell that has a configured uplink, and the mapping from each serving cell to a TAG may be configured by Radio Resource Control (RRC). As an example, a TAG may be associated with a PCell and one or more secondary cells. In such an example, the UE may use the PCell as a timing reference. As another example, a TAG may be associated with one or more secondary cells and may not include a PCell. In such an example, the UE may use one of the active SCells associated with the TAG as a timing reference.

[0084] The network can communicate with the UE based on one or more beams (spatial filters). For example, the network's base station can transmit beam-shaped signals to the UE in one or more directions corresponding to one or more beams. The base station and the UE can perform beam training to determine the optimal receiving and transmitting directions for the base station and the UE.

[0085] Beam switching can be performed in response to different conditions. For example, a Transmit Configuration Indicator (TCI) state change can be transmitted by the base station, allowing the UE to switch to a new beam for the TCI state. This TCI state change enables the UE to find the optimal UE receive beam corresponding to that TCI state from the base station and switch to such a beam. Beam switching allows for enhanced or improved connectivity between the UE and the base station by ensuring that the transmitter and receiver communicate using the same configured beam set. The TCI state may include quasi-co-location (QCL) information, which the UE can use to derive timing / frequency errors and / or transmit / receive spatial filtering for transmit / receive signals.

[0086] The various processes used to manage and control beams used in wireless communication are collectively referred to as "beam management." The process of selecting the beam to switch to for a data channel or control channel is called "beam selection." In some wireless communication systems, beam selection for data or control channels can be performed on beams within the same Physical Cell Identifier (PCI). The PCI may be associated with the TRP (Transmission Restriction Point). Figure 5A This is an example diagram 500 illustrating beam management. For example... Figure 5A As illustrated, for UE 502, beam selection 506 can be used for the beam within PCI 504A, and the beams associated with PCI 504B and PCI 504C may not be used. For example, each of PCI 504A, PCI 504B, and PCI 504C can be associated with a different TRP.

[0087] As an example, a UE may encounter two types of mobility—cell-level mobility and beam-level mobility (which can be beam-based mobility). For cell-level mobility, the UE may experience inter-base station handover. In some wireless communication systems, for beam-level mobility, as previously explained, beam switching can occur within the same base station.

[0088] In some wireless communication systems, inter-cell beam management can be based on beam-based mobility, where the indicated beam can come from a TRP with different PCIs for the serving cell. Benefits of beam-based mobility-based inter-cell beam management can include greater robustness against obstruction, more opportunities to achieve higher rank subscriber data management (SDM) across different cells, and generally more efficient communication between the UE and the network. Figure 5B This is an example illustration of inter-cell beam management, shown in Figure 550. Figure 5B As illustrated, for UE 552, beam selection 556 can be based on the beam within PCI 554A and the beams associated with PCI 554B and PCI 554C. For example, each of PCI 554A, PCI 554B, and PCI 554C can be associated with a different TRP.

[0089] For example, inter-cell beam management based on beam-based mobility can be facilitated by L1 and / or L2 signaling, such as UE-dedicated channels / RS, which can be associated with handover to TRPs with different PCIs based on a unified TCI update based on downlink control information (DCI) or medium access control (MAC) control element (MAC-CE). As used herein, this mobility can be referred to as L1 / L2 mobility.

[0090] In some aspects, the network can configure a set of cells for L1 / L2 mobility. This set of cells for L1 / L2 mobility can be referred to as the L1 / L2 mobility configuration cell set. A subset of the L1 / L2 mobility configuration cell set can be activated (e.g., using L1 or L2 control signaling) and can be referred to as the L1 / L2 mobility active cell set (which may also be called the L1 / L2 active mobility cell set). A subset of cells in the L1 / L2 mobility configuration cell set that are not activated or are indicated to be deactivated can be referred to as the L1 / L2 mobility deactivated cell set or the deactivated L1 / L2 mobility cell set. The L1 / L2 mobility active cell set can be a set of cells in the L1 / L2 mobility configuration cell set that are activated and readily available for data and control transmission. The L1 / L2 mobility deactivated cell set (which may be an L1 / L2 mobility candidate cell set) can be a group of cells in a configured set that are configured for UEs that are not yet deactivated (e.g., not used for data / control transfers before activation) and can be activated by L1 / L2 signaling. Once activated, the deactivated cells can be used for data and control transfers between the UE and the base station. L1 / L2 inter-cell mobility can reduce mobility latency. The configuration and maintenance of multiple candidate cells allows for faster application of the configuration for candidate cells, and the activated cell set provides a basis for dynamic handover between candidate serving cells (e.g., including SpCell and SCell) based on L1 or L2 signaling.

[0091] The L1 / L2-based inter-cell mobility procedures are applicable to many scenarios. These scenarios can include independent CA and NR-DC cases where the serving cell changes within a CG, intra-DU and intra-CU inter-DU cases (applicable to independent and CA cases where a new RAN interface is not expected), intra-frequency and inter-frequency cases, and FR1 and FR2 cases. In these scenarios, the source and destination cells can be synchronous or asynchronous.

[0092] For mobility management of an active cell set, L1 / L2 signaling can be used to activate / deactivate cells in the L1 / L2 mobility configuration cell set and select beams within the active cells (of the active cell set). When the UE moves, cells from the L1 / L2 mobility configuration cell set can be deactivated and activated by L1 / L2 signaling based on signal quality (e.g., based on measurements), load, etc. Example measurements may include cell coverage measurements represented by Radio Signal Received Power (RSRP) and quality measurements 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 may be L1 measurements, such as 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.).

[0093] In some respects, all cells in the L1 / L2 mobility configuration cell set can belong to the same DU, and these cells can operate on the same or different carrier frequencies. Cells in the L1 / L2 mobility configuration cell set can cover mobility areas.

[0094] When the UE moves, the PCell can be reselected or updated from a set of configured candidate PCells based on the UE's measurements of the candidate cells (e.g., L1 measurements such as Reference Received Power (RSRP), Reference Received Quality (RSRQ), Received Signal Strength Indicator (RSSI), etc.). Figure 6 Figure 600 illustrates an example of the associated handover between the UE's mobility and the primary cell (PCell). For example... Figure 6As illustrated, when UE 602 moves, UE 602 can update the PCell from the old PCell 604A to one of the candidate PCells including candidate PCell 604B, candidate PCell 604C, and candidate PCell 604D. A candidate PCell can be activated before being selected as the new PCell (e.g., the UE can receive a TAG activation from the network), or it can be deactivated before being selected as the new PCell. In some aspects, each of candidate PCell 604B, candidate PCell 604C, and candidate PCell 604D can be associated with a different TAG. For example, candidate PCell 604B can be associated with TAG 1, candidate PCell 604C can be associated with TAG 2, and candidate PCell 604D can be associated with TAG 3. In some aspects, the old PCell 604A can be configured with TAG 0. In some aspects, each of TAG 0, TAG 1, TAG 2, and TAG 3 may be pre-configured for UE 602 (e.g., before UE movement). In some aspects, when a TAG is assigned to each deactivated candidate PCell, other cells may share the same TAG. For example, if candidate PCell 604B is deactivated before being selected as the new PCell, other cells may share TAG 1 with candidate PCell 604B. For example, other cells sharing TAG 1 with candidate PCell 604B may include candidate PCells and SCells in the candidate cell group associated with the physical cell site of candidate PCell 604B. In some aspects, candidate PCells and SCells in the candidate cell group associated with the physical cell site of candidate PCell 604B may not be activated before candidate PCell 604B is activated and selected as the new PCell. In some wireless communication systems, the UE may support up to four TAGs. In some aspects, the UE may support more than four TAGs.

[0095] Figure 7 This is illustration 700, showing an example cell configuration. For example... Figure 7As illustrated, CU 702 (which may correspond to a component of a base station such as a gNB) may be associated with a first DU 704 (and other DUs). An L1 / L2 mobility configuration cell set 706 may be associated with the first DU 704 and may include an L1 / L2 mobility active cell set 708 and an L1 / L2 mobility deactivated cell set 710. The L1 / L2 mobility configuration cell set 706 may also include one or more cells that are not currently in the L1 / L2 mobility active cell set 708 or the current L1 / L2 mobility deactivated cell set 710. For example, at a given time, the L1 / L2 mobility active cell set 708 may include a first subset of cells in the L1 / L2 mobility configuration cell set, and the L1 / L2 mobility deactivated cell set 710 may include a second non-overlapping subset of cells in the L1 / L2 mobility configuration cell set. One or more cells in the L1 / L2 mobility configuration cell set can be retained, which are not in a first subset (e.g., active) or a second subset (e.g., deactivated). UE 712 can use cells in the L1 / L2 mobility active cell set 708 for data channel communication and control channel communication.

[0096] A UE can be configured with a set of cells for L1 / L2 mobility within a carrier aggregation (CA) framework. This set of cells for L1 / L2 mobility can be configured using RRC and can include a single PCell and multiple SCells at a given time. An SCell can be updated to a PCell (e.g., changed to a PCell configuration or activated as a PCell) using L1 / L2 signaling, and a PCell can be updated to (e.g., changed to) an SCell using L1 / L2 signaling. For example, a cell can handover between the PCell and SCell acting as the UE.

[0097] The UE can be configured with a set of cells (C1, ..., C6) for L1 / L2 mobility. This set of cells (e.g., for L1 / L2 inter-cell mobility) can be configured via RRC signaling. Cells in the configuration set (including cells configured to act as PCells and cells configured to act as SCells) can be further characterized into two groups: active cells and deactivated cells. Active cells can be the currently active serving cell and are used for data and control communication between the network and the UE. Deactivated cells are cells that are currently deactivated (and therefore do not have active data or control communication with the UE) but can be quickly activated via L1 / L2 signaling from the network to the UE. The UE can exchange data and control communications or monitor data and control communications with the base station on active cells, and the UE can perform L1 measurements on all cells in the L1 / L2 configured cell set (including both active and deactivated cells).

[0098] In CA, SCell can be activated by MAC-CE. PCell can be changed using L3 signaling. This disclosure presents joint cell activation / deactivation messages for SCell and PCell updates in L1 / L2 mobility. Joint cell activation / deactivation facilitates fast and efficient L1 / L2 mobility and can potentially include additional configuration options for activated SCell and PCell. Additionally, this disclosure also presents several options for joint MAC-CE and / or DCI designs.

[0099] In some aspects of this disclosure, cells in the L1 / L2 mobility configuration set can be controlled (e.g., activated and deactivated) by L1 / L2 mobility signaling that communicates cell activation / deactivation and PCell activation / deactivation (in a single joint message). Joint L1 / L2 signaling containing SCell activation / deactivation and PCell activation / deactivation commands allows simultaneous cell activation and designation as a PCell, as well as simultaneous cell deactivation and PCell reassignment. If no PCell change exists and only SCell activation / deactivation is indicated, a MAC-CE for SCell activation / deactivation can be sent. As presented herein, the MAC-CE can include an indication in the joint message that no PCell change exists. Joint L1 / L2 signaling can be implemented in either a DCI format or a MAC-CE format. The DCI or MAC-CE format can include a logical channel ID (LCID) or eLCID for L1 / L2 mobility cell activation / deactivation that includes both SCell and PCell activation. The MAC-CE or DCI format may include one or more of the following: a pointer to the cell ID that is activated / deactivated or a bit in the setting bitmap corresponding to the cell ID; a field indicating whether the cell is activated as a new PCell; a pointer to the parameter spCellConfig (PCell configuration) to be activated if multiple configurations are available for the cell, or a bit in the setting bitmap corresponding to one of the available PCell configurations; the TCI state to be activated for each active cell; the RS for beamfinding; and the RS ID for L1 reporting when the cell is deactivated (which may be provided during cell handover or may always be provided). Cells not configured for L1 / L2 mobility may be controlled by the CA activation / deactivation MAC-CE, for example, instead of by the L1 / L2 mobility MAC-CE.

[0100] In some wireless communication systems, UE-based TA updates (also referred to as "UE-based TA measurement" or "UE-based TA acquisition") can be used, where the UE determines the TA based on the Rx timing difference between the current serving cell (also referred to as the "current active serving cell") and candidate cells, and the TA value of the current serving cell. The UE may indicate its capability for UE-based TA updates (e.g., support) in capability information signaled to the network. For a UE indicating support for UE-based TA updates, the network may configure the UE to perform such updates (e.g., by sending configuration for UE-based TA updates). In addition to UE-based TA updates, PDCCH instruction-based TA updates can also be used. PDCCH instructions may include signaling for triggering a random access procedure at the UE. The aspects provided herein enable the provision of timing instances for UE-based TA updates, which facilitates more efficient UE-based TA updates, thereby enabling more efficient wireless communication processing.

[0101] Figure 8 Figure 800 illustrates example communication between network entity 804 and UE 802. Network entity 804 can be a network node. A network node can be implemented as a converged base station, a decomposed base station, an integrated access and backhaul (IAB) node, a relay node, a sidelink node, etc. The network entity can be implemented in a converged or monolithic base station architecture, or alternatively in a decomposed base station architecture, and may include one or more of a CU, DU, RU, near real-time (near RT) RAN intelligent controller (RIC), or non-real-time (non-RT) RIC. In some aspects, such as Figure 8 As illustrated, UE 802 may send capability information 806 indicating support for UE-based TA updates. As used herein, the term "capability information" can be information indicating UE capabilities that can be carried in signaling.

[0102] Based on capability information 806 indicating support for UE-based TA updates for UE 802, network entity 804 may send configuration 808 for UE-based TA updates for candidate cells to UE 802. In some aspects, for UE-based TA updates, the time instance for updating the TA for UE 802 may be determined based on instructions from network entity 804 (e.g., in configuration 808) or based on a configuration without signaling from network entity 804. For example, configuration 808 or the configuration without signaling from network entity 804 may include periodicity, DL RS timing, time, or other information indicating the time instance for UE-based TA updates. At 810, UE 802 may perform a UE-based TA update based on the determined time instance. In some aspects, at 810, UE 802 may perform an update for candidate cells (e.g., as in conjunction with) a change in environment (which may be referred to as "the occurrence of a condition"). Figures 6 to 7 The term "environmental change" refers to a UE-related change that can trigger a TA update without signaling from the network. For example, an environmental change may occur when the UE has not updated its TA for a duration longer than a threshold. An environmental change may also occur when RSRP, location, Doppler information, angle, or other location-related or signaling-related aspects change at least a configured threshold. In some aspects, environmental changes may be configured by network entities (e.g., in the configuration used for UE-based TA updates). In some aspects, environmental changes may be configured without signaling from network entities. The inputs associated with the environmental change may change compared to the last time of the UE-based TA update. For example, at least one of the following parameters may be changed: the timing of the serving or candidate cell RS to be measured, the TA of the serving cell, the DL Tx timing difference between the serving cell and the candidate cell, or other parameters.

[0103] In some aspects, for UE-based TA updates, network entity 804 may (e.g., in configuration 808) indicate a periodic reference time instance at which UE 802 may begin updating the TA of a candidate cell based on the latest measurement results. Such a reference time instance may be represented by a slot start time. In some aspects, the minimum periodicity of the reference time instance may be based on the UE capabilities indicated in capability information 806. In some aspects, the processing time used to determine the TA after each reference time instance may be based on the UE capabilities indicated in capability information 806.

[0104] Figure 9 This is diagram 900 illustrating example reference times and processing times associated with UE-based TA updates. (See diagram 900.) Figure 9As illustrated, there may be a first reference time 910A, a second reference time 910B, and a third reference time 910C. The periodicity of the reference times may be periodicity 912. The network entity may instruct the UE to update the TA starting from the third reference time 910C. After processing time 914, the UE may update the TA at 916.

[0105] In some aspects, network entity 804 may (e.g., in configuration 808) provide UE 802 with information for determining the TA (e.g., at 810) of candidate cells. In some aspects, the information provided may include the cell ID, measurement RS ID, and corresponding measurement timing for each of the measured serving cell and candidate cells. In some aspects, the information provided may include the difference between the UL Rx timing and DL Tx timing at the serving cell (which may be the serving cell TA). In some aspects, the information provided may include the DL Tx timing difference (dT) between the two measurement RS IDs.

[0106] Figure 10A This is an example diagram 1000 illustrating uplink and downlink timing used in a base station. For example... Figure 10A As illustrated, there may be a candidate cell's UL timing 1012A and a candidate cell's DL timing 1012B, with the candidate cell's DL timing starting dT later than the candidate cell's UL timing 1012A. There may also be a serving cell's UL timing 1014A and a serving cell's DL timing 1014B.

[0107] Figure 10B This is an example illustration of uplink and downlink timing used in a UE, shown in Figure 1050. Figure 10A As illustrated, there may be a candidate cell's UL timing 1052A and a candidate cell's DL timing 1052B. The candidate cell's DL timing may start d_TA later than the candidate cell's UL timing 1052A, and d_TA may be determined based on dT and dR (referencing TA). When there may be a serving cell's UL timing 1054A and a serving cell's DL timing 1054B, the serving cell's DL timing may start TA1 later than the serving cell's UL timing 1054A, and TA1 may be equal to the serving cell's indication TA.

[0108] Return to reference Figure 8In some aspects, network entity 804 may send a cell handover command 812 to UE 802, enabling UE 802 to hand over to a candidate cell to communicate with network entity 804 (e.g., communication 816). In some aspects, for UE-based TA acquisition, after receiving the cell handover command, at 815, UE 802 may apply the determined TA (e.g., determined at TA update 810) to the initial UL transmission on a new cell having the same TAG as the candidate cell associated with the determined TA. In some aspects, UE 802 may receive a PDCCH instruction 814 from network entity 804 (e.g., to facilitate a random access procedure associated with the new cell). In some aspects, the PDCCH instruction 814 may be associated with a PDCCH instruction-based TA update. In some aspects, a TA based on a PDCCH instruction-based TA update according to PDCCH instruction 814 or a UE-based TA update at 810 may be used. In some aspects, both the TA updated based on the TA based on the PDCCH instruction 814 and the TA updated based on the UE-based TA at 810 can be used. For example, the most recently acquired TA can be used, either the TA updated based on the PDCCH instruction 814 or the TA updated based on the UE-based TA at 810. In some aspects, the cell handover command 812 can (e.g., based on an explicit indicator) indicate which TA can be used, either the TA updated based on the PDCCH instruction 814 or the TA updated based on the UE-based TA at 810. In some aspects, the cell handover command 812 can implicitly indicate which TA can be used, either the TA updated based on the PDCCH instruction 814 or the TA updated based on the UE-based TA at 810. For example, when the PDCCH instruction 814 is associated with a valid TA, the TA updated based on the PDCCH instruction 814 can be used. If PDCCH instruction 814 is not associated with a valid TA, the TA updated based on the UE-based TA at 810 can be used.

[0109] Figure 11 This is a flowchart 1100 of a wireless communication method. The method can be performed by a UE (e.g., UE 104, UE 802; device 1504).

[0110] At 1102, the UE may send capability information to a network entity indicating support for UE-based TA updates between the serving cell associated with the network entity and candidate cells associated with the network entity for L1 or L2 mobility. For example, UE 802 may send capability information 806 to network entity 804, indicating support for UE-based TA updates between the serving cell associated with the network entity and candidate cells associated with the network entity for L1 or L2 mobility. In some aspects, 1102 may be performed by TA component 198.

[0111] At 1104, the UE may receive configuration 808 for UE-based TA updates from network entity 804. For example, UE 802 may receive configuration for UE-based TA updates from the network entity. In some aspects, 1104 may be performed by TA component 198. In some aspects, the configuration indicates a time instance, a DL RS associated with the time instance, or a periodicity associated with the time instance for the UE-based TA update. In some aspects, the UE may (e.g., in the configuration) receive a reference time associated with the time instance from the network entity. In some aspects, the reference time is represented by the slot start time. In some aspects, the reference time is associated with a periodicity, and the periodicity is based on capability information. In some aspects, the time difference between the reference time and the time instance is based on capability information. In some aspects, the time instance for UE-based TA updates is based on the occurrence of a condition associated with the UE, wherein the condition is based on at least one of the following: the difference between the current time and the time of the last update associated with a previously derived TA, RSRP, location, Doppler information, or angle information. In some aspects, the UE may (e.g., in configuration) receive from a network entity a corresponding cell identifier associated with the serving cell and a candidate cell, a corresponding measurement reference signal ID, and a corresponding associated measurement reference signal timing, as well as a time difference (TA). In some aspects, the UE may (e.g., in configuration) receive from a network entity information about the time difference between a first measurement reference signal ID associated with the serving cell and a second measurement reference signal ID associated with the candidate cell for determining the derived TA.

[0112] At 1106, the UE can utilize a candidate cell to transmit uplink or downlink transmissions based on the candidate cell's derived TA and the receive timing difference associated with the serving cell and the candidate cell, wherein the derived TA of the candidate cell is based on the serving cell's TA. For example, UE 802 can utilize a candidate cell to transmit uplink or downlink transmissions based on the candidate cell's derived TA and the receive timing difference associated with the serving cell and the candidate cell (e.g., 816), wherein the derived TA of the candidate cell is based on the serving cell's TA. In some aspects, 1106 can be performed by TA component 198.

[0113] Figure 12 This is a flowchart 1200 of a wireless communication method. The method can be performed by a UE (e.g., UE 104, UE 802; device 1504).

[0114] At 1202, the UE may send capability information to a network entity indicating support for UE-based TA updates between the serving cell associated with the network entity and candidate cells associated with the network entity for L1 or L2 mobility. For example, UE 802 may send capability information 806 to network entity 804, indicating support for UE-based TA updates between the serving cell associated with the network entity and candidate cells associated with the network entity for L1 or L2 mobility. In some aspects, 1202 may be performed by TA component 198.

[0115] At 1204, the UE may receive configuration 808 for UE-based TA updates from network entity 804. For example, UE 802 may receive configuration for UE-based TA updates from the network entity. In some aspects, 1204 may be performed by TA component 198. In some aspects, the configuration indicates a time instance, a DL RS associated with the time instance, or a periodicity associated with the time instance for the UE-based TA update. In some aspects, the UE may (e.g., in the configuration) receive a reference time associated with the time instance from the network entity. In some aspects, the reference time is represented by the slot start time. In some aspects, the reference time is associated with a periodicity, and the periodicity is based on capability information. In some aspects, the time difference between the reference time and the time instance is based on capability information. In some aspects, the time instance for UE-based TA updates is based on the occurrence of a condition associated with the UE, wherein the condition is based on at least one of the following: the difference between the current time and the time of the last update associated with a previously derived TA, RSRP, position, Doppler information, or angle information. In some aspects, the UE may (e.g., in configuration) receive from a network entity a corresponding cell identifier associated with the serving cell and a candidate cell, a corresponding measurement reference signal ID, and a corresponding associated measurement reference signal timing, as well as a time difference (TA). In some aspects, the UE may (e.g., in configuration) receive from a network entity information about the time difference between a first measurement reference signal ID associated with the serving cell and a second measurement reference signal ID associated with the candidate cell for determining the derived TA.

[0116] At 1212, the UE may receive a cell handover command from a network entity indicating a handover to a candidate cell. For example, UE 802 may receive a cell handover command 812 indicating a handover to a candidate cell from a network entity. In some aspects, 1212 may be executed by TA component 198.

[0117] At 1214, the UE may receive a PDCCH instruction associated with a candidate cell from a network entity, wherein the PDCCH instruction is associated with a second TA. For example, UE 802 may receive a PDCCH instruction 814 associated with a candidate cell from a network entity, wherein the PDCCH instruction is associated with a second TA. In some aspects, 1214 may be executed by TA component 198.

[0118] At 1216, the UE may apply a TA. For example, UE 802 may apply the TA at 810. In some aspects, 1216 may be performed by TA component 198. In some aspects, the UE may apply a derived TA or a second TA. In some aspects, the UE may apply the most recently acquired TA from either the derived TA or the second TA. In some aspects, the cell handover command indicates the derived TA or the second TA, and the UE may apply the derived TA or the second TA based on the cell handover command. In some aspects, the cell handover command indicates the derived TA or the second TA, and the UE may apply the second TA if it is valid, and apply the derived TA if no valid TA is associated with the PDCCH instruction.

[0119] At 1206, the UE can utilize a candidate cell to communicate uplink or downlink transmissions based on the derived TA of the candidate cell and the receive timing difference associated with the serving cell and the candidate cell, wherein the derived TA of the candidate cell is based on the TA of the serving cell. For example, UE 802 can utilize a candidate cell to communicate uplink or downlink transmissions based on the derived TA of the candidate cell and the receive timing difference associated with the serving cell and the candidate cell (e.g., 816), wherein the derived TA of the candidate cell is based on the TA of the serving cell. In some aspects, 1206 can be performed by TA component 198.

[0120] Figure 13 This is a flowchart 1300 of a wireless communication method. The method can be performed by network entities (e.g., base station 102, network entity 804, network entity 1502, network entity 1602).

[0121] At 1302, the network entity can obtain capability information associated with the UE, which indicates support for UE-based TA updates between the serving cell associated with the network entity and candidate cells associated with the network entity for L1 or L2 mobility. For example, network entity 804 can obtain capability information 806 associated with the UE 802, which indicates support for UE-based TA updates between the serving cell associated with the network entity and candidate cells associated with the network entity for L1 or L2 mobility. In some aspects, 1302 can be performed by TA component 199.

[0122] At 1304, the network entity may send a configuration for a UE-based TA update to the UE. For example, network entity 804 may send a configuration 808 for a UE-based TA update to the UE 802. In some aspects, 1304 may be performed by TA component 199. In some aspects, the configuration indicates a time instance, a DLRS associated with the time instance, or a periodicity associated with the time instance for the UE-based TA update. In some aspects, the network entity may send a reference time associated with the time instance to the UE (e.g., in the configuration). In some aspects, the reference time is represented by the slot start time. In some aspects, the reference time is associated with a periodicity, and the periodicity is based on capability information. In some aspects, the time difference between the reference time and the time instance is based on capability information. In some aspects, the time instance for the UE-based TA update is based on the occurrence of a condition associated with the UE, wherein the condition is based on at least one of the following: the difference between the current time and the time of the last update associated with the previously derived TA, RSRP, location, Doppler information, or angle information. In some aspects, network entities may transmit to the UE (e.g., in configuration) the corresponding cell identifier associated with the serving cell and the candidate cell, the corresponding measurement reference signal ID, and the corresponding associated measurement reference signal timing, as well as the time difference (TA). In some aspects, network entities may transmit to the UE (e.g., in configuration) information about the time difference between a first measurement reference signal ID associated with the serving cell and a second measurement reference signal ID associated with the candidate cell for determining the derived TA.

[0123] At 1306, a network entity may transmit uplink or downlink transmissions via a candidate cell based on the candidate cell's derived TA and the receive timing difference associated with the serving cell and the candidate cell, wherein the candidate cell's derived TA is based on the serving cell's TA. For example, network entity 804 may transmit uplink or downlink transmissions via a candidate cell based on the candidate cell's derived TA and the receive timing difference associated with the serving cell and the candidate cell (e.g., 816), wherein the candidate cell's derived TA is based on the serving cell's TA. In some aspects, 1306 may be performed by TA component 199.

[0124] Figure 14 This is a flowchart 1400 of a wireless communication method. The method can be performed by network entities (e.g., base station 102, network entity 804, network entity 1502, network entity 1602).

[0125] At 1402, the network entity can obtain capability information associated with the UE, which indicates support for UE-based TA updates between the serving cell associated with the network entity and candidate cells associated with the network entity for L1 or L2 mobility. For example, network entity 804 can obtain capability information 806 associated with the UE 802, which indicates support for UE-based TA updates between the serving cell associated with the network entity and candidate cells associated with the network entity for L1 or L2 mobility. In some aspects, 1402 can be performed by TA component 199.

[0126] At 1404, a network entity may send a configuration for a UE-based TA update to a UE. For example, network entity 804 may send a configuration 808 for a UE-based TA update to a UE 802. In some aspects, 1404 may be performed by TA component 199. In some aspects, the configuration indicates a time instance, a DLRS associated with the time instance, or a periodicity associated with the time instance for the UE-based TA update. In some aspects, the network entity may send a reference time associated with the time instance to the UE (e.g., in the configuration). In some aspects, the reference time is represented by the slot start time. In some aspects, the reference time is associated with a periodicity, and the periodicity is based on capability information. In some aspects, the time difference between the reference time and the time instance is based on capability information. In some aspects, the time instance for the UE-based TA update is based on the occurrence of a condition associated with the UE, wherein the condition is based on at least one of the following: the difference between the current time and the time of the last update associated with a previously derived TA, RSRP, location, Doppler information, or angle information. In some aspects, network entities may transmit to the UE (e.g., in configuration) the corresponding cell identifier associated with the serving cell and the candidate cell, the corresponding measurement reference signal ID, and the corresponding associated measurement reference signal timing, as well as the time difference (TA). In some aspects, network entities may transmit to the UE (e.g., in configuration) information about the time difference between a first measurement reference signal ID associated with the serving cell and a second measurement reference signal ID associated with the candidate cell for determining the derived TA.

[0127] At 1412, the network entity may send a cell handover command to the UE indicating a handover to a candidate cell. For example, network entity 804 may send a cell handover command 812 to the UE indicating a handover to a candidate cell. In some aspects, 1402 may be performed by TA component 199.

[0128] At 1414, the network entity may send a PDCCH instruction associated with a candidate cell to the UE, wherein the PDCCH instruction is associated with a second TA. For example, network entity 804 may send a PDCCH instruction 814 associated with a candidate cell to the UE, wherein the PDCCH instruction is associated with a second TA. In some aspects, 1404 may be performed by TA component 199.

[0129] At 1406, a network entity may transmit uplink or downlink transmissions via a candidate cell based on the candidate cell's derived TA and the receive timing difference associated with the serving cell and the candidate cell, wherein the candidate cell's derived TA is based on the serving cell's TA. For example, network entity 804 may transmit uplink or downlink transmissions via a candidate cell based on the candidate cell's derived TA and the receive timing difference associated with the serving cell and the candidate cell (e.g., 816), wherein the candidate cell's derived TA is based on the serving cell's TA. In some aspects, 1406 may be performed by TA component 199.

[0130] Figure 15Figure 1500 illustrates an example of a hardware implementation for device 1504. Device 1504 may be a UE, a component of a UE, or implement UE functionality. In some aspects, device 1504 may include a cellular baseband processor 1524 (also referred to as a modem) coupled to one or more transceivers 1522 (e.g., cellular RF transceivers). Cellular baseband processor 1524 may include on-chip memory 1524'. In some aspects, device 1504 may also include one or more Subscriber Identity Module (SIM) cards 1520 and an application processor 1506 coupled to a Secure Digital Card (SD) card 1508 and a screen 1510. Application processor 1506 may include on-chip memory 1506'. In some aspects, device 1504 may also include a Bluetooth module 1512, a WLAN module 1514, a satellite system module 1516 (e.g., a GNSS module), one or more sensor modules 1518 (e.g., a barometric pressure sensor / altimeter; motion sensors such as an inertial management 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), an additional memory module 1526, a power source 1530, and / or a camera 1532. Bluetooth module 1512, WLAN module 1514, and satellite system module 1516 may include an on-chip transceiver (TRX) / receiver (RX). Cellular baseband processor 1524 communicates with UE 104 and / or RUs associated with the same network entity 1502 via transceiver 1522 through one or more antennas 1580. Cellular baseband processor 1524 and application processor 1506 may each include computer-readable media / memory 1524', 1506' respectively. Additional memory module 1526 may also be considered a computer-readable media / memory. Each computer-readable media / memory 1524', 1506', 1526 may be non-transitory. Cellular baseband processor 1524 and application processor 1506 are each responsible for general processing, including executing software stored on the computer-readable media / memory. This software, when executed by cellular baseband processor 1524 / application processor 1506, causes cellular baseband processor 1524 / application processor 1506 to perform the various functions described herein. The computer-readable media / memory may also be used to store data manipulated by cellular baseband processor 1524 / application processor 1506 during software execution. Cellular baseband processor 1524 / application processor 1506 may be a component of UE 350 and may include memory 360 and / or at least one of TX processor 368, RX processor 356, and controller / processor 359.In one configuration, device 1504 may be a processor chip (modem and / or application) and includes only cellular baseband processor 1524 and / or application processor 1506, while in another configuration, device 1504 may be the entire UE (see, for example). Figure 3 (350) and includes an additional module of device 1504.

[0131] As discussed herein, TA component 198 may be configured to send capability information to a network entity indicating support for UE-based TA updates between a serving cell associated with the network entity and a candidate cell associated with the network entity for L1 or L2 mobility. In some aspects, TA component 198 may be further configured to receive configuration for UE-based TA updates from the network entity. In some aspects, TA component 198 may be further configured to utilize the candidate cell to convey uplink or downlink transmissions based on the candidate cell's derived TA and the reception timing difference associated with the serving cell and the candidate cell, the derived TA of the candidate cell being based on the serving cell's TA. TA component 198 may be within cellular baseband processor 1524, application processor 1506, or both cellular baseband processor 1524 and application processor 1506. TA component 198 may be one or more hardware components specifically configured to execute the process / algorithm, implemented by one or more processors configured to execute the process / algorithm, stored in a computer-readable medium for implementation by one or more processors, or some combination thereof. As shown in the figure, apparatus 1504 may include various components configured for various functions. In one configuration, apparatus 1504, and particularly cellular baseband processor 1524 and / or application processor 1506, includes components for transmitting capability information to a network entity, the capability information indicating support for UE-based TA updates between a serving cell associated with the network entity and a candidate cell associated with the network entity for L1 or L2 mobility. In some aspects, apparatus 1504 may also include components for receiving configurations for UE-based TA updates from the network entity. In some aspects, apparatus 1504 may also include components for communicating uplink or downlink transmissions using the candidate cell based on a derived TA of the candidate cell and a receive timing difference associated with the serving cell and the candidate cell, the derived TA of the candidate cell being based on the TA of the serving cell. In some aspects, apparatus 1504 may also include components for receiving a reference time associated with a time instance from the network entity. In some aspects, the apparatus 1504 may further include components for receiving from a network entity a corresponding cell identifier, a corresponding measurement reference signal ID, and a corresponding associated measurement reference signal timing, as well as a time transition (TA), associated with the serving cell and the candidate cell. In some aspects, the apparatus 1504 may further include components for receiving from a network entity information regarding the time difference between a first measurement reference signal ID associated with the serving cell and a second measurement reference signal ID associated with the candidate cell, for determining a derived TA. In some aspects, the apparatus 1504 may further include components for receiving from a network entity a cell handover command indicating a handover to the candidate cell.In some aspects, apparatus 1504 may further include components for receiving a Physical Downlink Control Channel (PDCCH) instruction associated with a candidate cell from a network entity, wherein the PDCCH instruction is associated with a second TA. In some aspects, apparatus 1504 may further include components for applying a derived TA or a second TA. In some aspects, apparatus 1504 may further include components for applying the most recently acquired TA among the derived TA and the second TA. In some aspects, apparatus 1504 may further include components for applying a derived TA or a second TA based on a cell handover command. In some aspects, apparatus 1504 may further include components for applying the second TA if it is valid, and applying the derived TA if no valid TA is associated with the PDCCH instruction. The component may be a TA component 198 of apparatus 1504 configured to perform the functions described herein. As described herein, apparatus 1504 may include a TX processor 368, an RX processor 356, and a controller / processor 359. Therefore, in one configuration, the component may be a TX processor 368, an RX processor 356, and / or a controller / processor 359 configured to perform the functions described therein.

[0132] Figure 16Figure 1600 illustrates an example of a hardware implementation for network entity 1602. Network entity 1602 may be a BS, a component of a BS, or implement BS functionality. Network entity 1602 may include at least one of CU 1610, DU 1630, or RU 1640. For example, depending on the layer functionality handled by component 199, network entity 1602 may include CU 1610; both CU 1610 and DU 1630; each of CU 1610, DU 1630, and RU 1640; DU 1630; both DU 1630 and RU 1640; or RU 1640. CU 1610 may include CU processor 1612. CU processor 1612 may include on-chip memory 1612'. In some aspects, CU 1610 may also include an additional memory module 1614 and a communication interface 1618. CU 1610 communicates with DU 1630 via a midhaul link, such as an F1 interface. DU 1630 may include a DU processor 1632. DU processor 1632 may include on-chip memory 1632'. In some aspects, DU 1630 may also include an additional memory module 1634 and a communication interface 1638. DU 1630 communicates with RU 1640 via a fronthaul link. RU 1640 may include an RU processor 1642. RU processor 1642 may include on-chip memory 1642'. In some aspects, RU 1640 may also include an additional memory module 1644, one or more transceivers 1646, an antenna 1680, and a communication interface 1648. RU 1640 communicates with UE 104. On-chip memories 1612', 1632', 1642' and additional memory modules 1614, 1634, 1644 may each be considered as computer-readable media / memory. Each computer-readable medium / memory can be non-transitory. Each of processors 1612, 1632, and 1642 is responsible for general processing, including executing software stored on the computer-readable medium / memory. When executed by the corresponding processor, the software causes the processor to perform the various functions described herein. The computer-readable medium / memory can also be used to store data manipulated by the processor while executing the software.

[0133] As discussed herein, TA component 199 may be configured to obtain capability information associated with a UE, indicating support for UE-based TA updates between a serving cell associated with a network entity and a candidate cell associated with a network entity for L1 or L2 mobility. In some aspects, TA component 199 may be further configured to transmit configurations for UE-based TA updates to a UE. In some aspects, TA component 199 may be further configured to transmit uplink or downlink transmissions via a candidate cell based on a derived TA of the candidate cell and a receive timing difference associated with the serving cell and the candidate cell, the derived TA of the candidate cell being based on the TA of the serving cell. TA component 199 may be located within one or more processors of one or more of CU 1610, DU 1630, and RU 1640. TA component 199 may be one or more hardware components specifically configured to perform the process / algorithm, implemented by one or more processors configured to perform the process / algorithm, stored in a computer-readable medium for implementation by one or more processors, or some combination thereof. Network entity 1602 may include a variety of components configured for various functions. In one configuration, network entity 1602 includes components for obtaining capability information associated with a UE, indicating support for UE-based TA updates between a serving cell associated with the network entity and a candidate cell associated with the network entity for L1 or L2 mobility. In some aspects, network entity 1602 may also include components for transmitting a configuration for UE-based TA updates to the UE. In some aspects, network entity 1602 may also include components for transmitting uplink or downlink transmissions via a candidate cell based on a derived TA from the candidate cell and a receive timing difference associated with the serving cell and the candidate cell, the derived TA from the candidate cell being based on the TA of the serving cell. In some aspects, network entity 1602 may also include components for transmitting a reference time associated with a time instance to the UE. In some aspects, network entity 1602 may also include components for transmitting to the UE a corresponding cell identifier associated with the serving cell and the candidate cell, a corresponding measurement reference signal ID, a corresponding associated measurement reference signal timing, and a TA. In some aspects, network entity 1602 may further include components for transmitting information to the UE regarding the time difference between a first measurement reference signal ID associated with the serving cell and a second measurement reference signal ID associated with the candidate cell to determine a derived TA. In some aspects, network entity 1602 may further include components for transmitting a cell handover command to the UE indicating a handover to the candidate cell. In some aspects, network entity 1602 may further include components for transmitting a physical downlink control channel (PDCCH) instruction associated with the candidate cell to the UE, wherein the PDCCH instruction is associated with the second TA.The component may be a TA component 199 of network entity 1602 configured to perform the functions described herein. As described herein, network entity 1602 may include a TX processor 316, an RX processor 370, and a controller / processor 375. Therefore, in one configuration, the component may be the TX processor 316, the RX processor 370, and / or the controller / processor 375 configured to perform the functions described herein.

[0134] It should be understood that the specific order or hierarchy of the boxes in the disclosed process / flowcharts is merely an example of the exemplary method. It should be understood that the specific order or hierarchy of the boxes in the process / flowcharts may be rearranged based on design preferences. Furthermore, some boxes may be combined or omitted. The appended method claims present the elements of various boxes in a sample order, but are not limited to the given specific order or hierarchy.

[0135] 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 apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not limited to the aspects described herein but should be given the full scope consistent with the language of the claims. Unless specifically stated otherwise, references to elements in the singular form do not mean "one and only one," but rather "one or more." Terms such as "if," "when," and "simultaneously" 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 the occurrence of an action or during the occurrence of an action, but simply suggest that if the condition is met, then the action will occur, but 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 superior to other aspects. Unless specifically stated otherwise, the term "some" refers to 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 "A, B, C, or any combination thereof" include any combination of A, B, and / or C, which may include multiple A, multiple B, or multiple C. 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 "A, B, C, or any combination thereof" 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 interpreted as a collection of elements, where the number of elements is one or more. Therefore, for a set of X, X will include one or more elements. If the first device receives data from or sends data to the second device, data can be received / sent directly between the first and second devices, or indirectly between the first and second devices via a set of devices. All structural and functional equivalents of the elements throughout the various aspects described herein that are known to or will later be known to those skilled in the art are expressly incorporated herein by reference and are covered by the claims. Furthermore, nothing disclosed herein is intended to be offered to the public, whether or not such disclosure is explicitly recited in the claims. The words “module,” “mechanism,” “element,” “device,” etc., cannot replace the word “component.” Therefore, no claim element will be construed as a component plus function unless the element is explicitly recited using the phrase “component for…”.

[0136] As used in this article, the phrase “based on” should not be interpreted as referring 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, conditions, factors, etc.) should be interpreted as “based on at least A”, unless otherwise stated differently.

[0137] The following aspects are merely illustrative and may be combined with other aspects or teachings described herein without limitation.

[0138] Aspect 1 is a method for wireless communication at a user equipment (UE), the method comprising: sending capability information to a network entity, the capability information indicating support for a UE-based TA update between a serving cell associated with the network entity and a candidate cell associated with the network entity for L1 or L2 mobility; receiving configuration for the UE-based TA update from the network entity; and using the candidate cell to convey uplink or downlink transmission based on a derived TA of the candidate cell and a reception timing difference associated with the serving cell and the candidate cell, the derived TA of the candidate cell being based on the TA of the serving cell.

[0139] Aspect 2 is the method according to aspect 1, wherein the configuration indicates a time instance for the UE-based TA update, a DL RS associated with the time instance, or a periodicity associated with the time instance.

[0140] Aspect 3 is the method according to aspect 2, the method further comprising: receiving a reference time associated with the time instance from the network entity.

[0141] Aspect 4 is the method according to aspect 3, wherein the reference time is represented by the time slot start time.

[0142] Aspect 5 is the method according to aspect 4, wherein the reference time is associated with the periodicity, and wherein the periodicity is based on the capability information.

[0143] Aspect 6 is the method according to any one of Aspects 4 to 5, wherein the time difference between the reference time and the time instance is based on the capability information.

[0144] Aspect 7 is the method according to any one of Aspects 1 to 6, wherein the time instance for the UE-based TA update is based on the occurrence of a condition associated with the UE, wherein the condition is based on at least one of the following: the difference between the current time and the time of the last update associated with the previously derived TA, the reference signal received power (RSRP), the location, Doppler information, or the angle information.

[0145] Aspect 8 is a method according to any one of Aspects 1 to 7, the method further comprising: receiving from the network entity a corresponding cell identifier associated with the serving cell and the candidate cell, a corresponding measurement reference signal ID and a corresponding associated measurement reference signal timing, and the TA.

[0146] Aspect 9 is a method according to any one of Aspects 1 to 8, the method further comprising: receiving from the network entity information about the time difference between a first measurement reference signal ID associated with the serving cell and a second measurement reference signal ID associated with the candidate cell for determining the derived TA.

[0147] Aspect 10 is a method according to any one of aspects 1 to 9, the method further comprising: receiving from the network entity a cell handover command indicating a handover to the candidate cell, and receiving from the network entity a physical downlink control channel (PDCCH) instruction associated with the candidate cell, wherein the PDCCH instruction is associated with a second TA.

[0148] Aspect 11 is the method according to aspect 10, the method further comprising: applying the derived TA or the second TA.

[0149] Aspect 12 is the method according to aspect 10, the method further comprising: applying the derived TA or the latest acquired TA from the second TA.

[0150] Aspect 13 is the method according to aspect 10, wherein the cell handover command indicates the derived TA or the second TA, and the method further includes: applying the derived TA or the second TA based on the cell handover command.

[0151] Aspect 14 is the method according to aspect 10, wherein the cell handover command indicates the derived TA or the second TA, and the method further includes: applying the second TA if the second TA is valid, and applying the derived TA if no valid TA is associated with the PDCCH command.

[0152] Aspect 15 is a method for wireless communication at a network entity, the method comprising: obtaining capability information associated with a UE, the capability information indicating support for a UE-based TA update between a serving cell associated with the network entity and a candidate cell associated with the network entity for L1 or L2 mobility; transmitting configuration for the UE-based TA update for the UE; and transmitting uplink or downlink transmissions via the candidate cell based on a derived TA of the candidate cell and a reception timing difference associated with the serving cell and the candidate cell, the derived TA of the candidate cell being based on the TA of the serving cell.

[0153] Aspect 16 is the method according to aspect 15, wherein the configuration indicates a time instance for the UE-based TA update, a downlink reference signal (DL RS) associated with the time instance, or a periodicity associated with the time instance.

[0154] Aspect 17 is the method according to aspect 16, the method further comprising: transmitting a reference time associated with the time instance for the UE.

[0155] Aspect 18 is the method according to aspect 17, wherein the reference time is represented by the time slot start time.

[0156] Aspect 19 is the method according to aspect 18, wherein the reference time is associated with the periodicity, and wherein the periodicity is based on the capability information.

[0157] Aspect 20 is the method according to any one of aspects 18 to 19, wherein the time difference between the reference time and the time instance is based on the capability information.

[0158] Aspect 21 is a method according to any one of aspects 15 to 20, wherein the time instance for the UE-based TA update is based on the occurrence of a condition associated with the UE, wherein the condition is based on at least one of the following: the difference between the current time and the time of the last update associated with the previously derived TA, the reference signal received power (RSRP), the location, Doppler information, or the angle information.

[0159] Aspect 22 is a method according to any one of aspects 15 to 21, the method further comprising: transmitting to the UE a corresponding cell identifier associated with the serving cell and the candidate cell, a corresponding measurement reference signal ID and a corresponding associated measurement reference signal timing, and the TA.

[0160] Aspect 23 is a method according to any one of aspects 15 to 22, the method further comprising: sending information to the UE about the time difference between a first measurement reference signal ID associated with the serving cell and a second measurement reference signal ID associated with the candidate cell for determining the derived TA.

[0161] Aspect 24 is a method according to any one of aspects 15 to 23, the method further comprising: sending a cell handover command to the UE indicating a handover to the candidate cell, and sending a physical downlink control channel (PDCCH) instruction associated with the candidate cell to the UE, wherein the PDCCH instruction is associated with a second TA.

[0162] Aspect 25 is an apparatus for wireless communication at a device, the apparatus including a memory and at least one processor coupled to the memory and based at least in part on information stored in the memory, the at least one processor being configured to implement any one of aspects 1 to 14.

[0163] Aspect 26 is the apparatus according to aspect 25, the apparatus further comprising a transceiver or antenna coupled to the at least one processor.

[0164] Aspect 27 is an apparatus for wireless communication at a device, the apparatus including components for implementing any one of aspects 1 to 14.

[0165] Aspect 28 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 14.

[0166] Aspect 29 is an apparatus for wireless communication at a device, the apparatus including a memory and at least one processor coupled to the memory and based at least in part on information stored in the memory, the at least one processor being configured to implement any one of aspects 15 to 25.

[0167] Aspect 30 is the apparatus according to aspect 29, the apparatus further comprising a transceiver or antenna coupled to the at least one processor.

[0168] Aspect 31 is an apparatus for wireless communication at a device, the apparatus including components for implementing any one of aspects 15 to 24.

[0169] Aspect 32 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 15 to 24.

Claims

1. An apparatus for wireless communication at a user equipment (UE), the apparatus comprising: Memory; and At least one processor, coupled to the memory, and configured, based at least in part on information stored in the memory, to cause the device to: Send capability information to a network entity, the capability information indicating support for UE-based advance timing (TA) updates between the serving cell associated with the network entity and the candidate cell associated with the network entity for Layer 1 (L1) or Layer 2 (L2) mobility; Receive configuration for the UE-based TA update from the network entity; as well as The candidate cell is used to transmit uplink or downlink transmissions based on the derived TA of the candidate cell and the receive timing difference associated with the serving cell and the candidate cell, wherein the derived TA of the candidate cell is based on the TA of the serving cell.

2. The apparatus of claim 1, wherein the configuration indicates a time instance for the UE-based TA update, a downlink reference signal (DLRS) associated with the time instance, or a periodicity associated with the time instance.

3. The apparatus of claim 2, wherein the at least one processor is further configured to cause the apparatus to: Receive the reference time associated with the time instance from the network entity.

4. The apparatus of claim 3, wherein the reference time is represented by the time slot start time.

5. The apparatus of claim 4, wherein the reference time is associated with the periodicity, and wherein the periodicity is based on the capability information.

6. The apparatus of claim 4, wherein the time difference between the reference time and the time instance is based on the capability information.

7. The apparatus of claim 1, wherein the time instance for the UE-based TA update is based on the occurrence of a condition associated with the UE, wherein the condition is based on at least one of the following: the difference between the current time and the time of the last update associated with the previously derived TA, the reference signal received power (RSRP), the location, Doppler information, or the angle information.

8. The apparatus of claim 1, wherein the at least one processor is further configured to cause the apparatus to: The network entity receives the corresponding cell identifier, the corresponding measurement reference signal identifier (ID), and the corresponding associated measurement reference signal timing, as well as the TA, associated with the serving cell and the candidate cell.

9. The apparatus of claim 1, wherein the at least one processor is further configured to cause the apparatus to: Information about the time difference between a first measurement reference signal ID associated with the serving cell and a second measurement reference signal ID associated with the candidate cell is received from the network entity to determine the derived TA.

10. The apparatus of claim 1, wherein the at least one processor is further configured to cause the apparatus to: The network entity receives a cell handover command indicating a handover to the candidate cell, and The network entity receives a Physical Downlink Control Channel (PDCCH) instruction associated with the candidate cell, wherein the PDCCH instruction is associated with a second TA.

11. The apparatus of claim 10, wherein the at least one processor is further configured to cause the apparatus to: Apply the derived TA or the second TA.

12. The apparatus of claim 10, wherein the at least one processor is further configured to cause the apparatus to: Apply the exported TA or the latest obtained TA from the second TA.

13. The apparatus of claim 10, wherein the cell handover command indicates the derived TA or the second TA, and wherein the at least one processor is further configured to cause the apparatus to: The derived TA or the second TA is applied based on the cell handover command.

14. The apparatus of claim 10, wherein the cell handover command indicates the derived TA or the second TA, and wherein the at least one processor is further configured to cause the apparatus to: If the second TA is valid, the second TA is applied; if no valid TA is associated with the PDCCH instruction, the derived TA is applied.

15. An apparatus for wireless communication at a network entity, the apparatus comprising: Memory; and At least one processor, coupled to the memory, and configured, based at least in part on information stored in the memory, to cause the device to: Obtain capability information associated with the user equipment (UE), the capability information indicating support for UE-based advance timing (TA) updates between the serving cell associated with the network entity and the candidate cell associated with the network entity for Layer 1 (L1) or Layer 2 (L2) mobility; Send configuration for the UE-based TA update to the UE; And to transmit uplink or downlink transmissions via the candidate cell based on the derived TA of the candidate cell and the receive timing difference associated with the serving cell and the candidate cell, wherein the derived TA of the candidate cell is based on the TA of the serving cell.

16. The apparatus of claim 15, wherein the configuration indicates a time instance for the UE-based TA update, a downlink reference signal (DL RS) associated with the time instance, or a periodicity associated with the time instance.

17. The apparatus of claim 16, wherein the at least one processor is further configured to cause the apparatus to: The reference time associated with the time instance is sent to the UE.

18. The apparatus of claim 17, wherein the reference time is represented by the time slot start time.

19. The apparatus of claim 18, wherein the reference time is associated with the periodicity, and wherein the periodicity is based on the capability information.

20. The apparatus of claim 18, wherein the time difference between the reference time and the time instance is based on the capability information.

21. The apparatus of claim 15, wherein the time instance for the UE-based TA update is based on the occurrence of a condition associated with the UE, wherein the condition is based on at least one of the following: the difference between the current time and the time of the last update associated with the previously derived TA, the reference signal received power (RSRP), the location, Doppler information, or the angle information.

22. The apparatus of claim 15, wherein the at least one processor is further configured to cause the apparatus to: The UE transmits the corresponding cell identifier, the corresponding measurement reference signal identifier (ID), and the corresponding associated measurement reference signal timing, as well as the TA, associated with the serving cell and the candidate cell.

23. The apparatus of claim 15, wherein the at least one processor is further configured to cause the apparatus to: The UE sends information about the time difference between a first measurement reference signal ID associated with the serving cell and a second measurement reference signal ID associated with the candidate cell to determine the derived TA.

24. The apparatus of claim 15, wherein the at least one processor is further configured to cause the apparatus to: The UE sends a cell handover command instructing the candidate cell to initiate a handover, and The UE sends a Physical Downlink Control Channel (PDCCH) instruction associated with the candidate cell, wherein the PDCCH instruction is associated with a second TA.

25. A method for wireless communication performed by a user equipment (UE), the method comprising: Send capability information to a network entity, the capability information indicating support for UE-based advance timing (TA) updates between the serving cell associated with the network entity and the candidate cell associated with the network entity for Layer 1 (L1) or Layer 2 (L2) mobility; Receive configuration for the UE-based TA update from the network entity; And to use the candidate cell to convey uplink or downlink transmissions based on the derived TA of the candidate cell and the receive timing difference associated with the serving cell and the candidate cell, wherein the derived TA of the candidate cell is based on the TA of the serving cell.

26. The method of claim 25, wherein the configuration indicates a time instance for the UE-based TA update, a downlink reference signal (DL RS) associated with the time instance, or a periodicity associated with the time instance.

27. The method according to claim 26, further comprising: Receive the reference time associated with the time instance from the network entity.

28. The method of claim 27, wherein the reference time is represented by the time slot start time.

29. The method of claim 28, wherein the reference time is associated with the periodicity, and wherein the periodicity is based on the capability information.

30. A method for performing wireless communication by a network entity, the method comprising: Obtain capability information associated with the user equipment (UE), the capability information indicating support for UE-based advance timing (TA) updates between the serving cell associated with the network entity and the candidate cell associated with the network entity for Layer 1 (L1) or Layer 2 (L2) mobility; Send configuration for the UE-based TA update to the UE; And to transmit uplink or downlink transmissions via the candidate cell based on the derived TA of the candidate cell and the receive timing difference associated with the serving cell and the candidate cell, wherein the derived TA of the candidate cell is based on the TA of the serving cell.

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