Timing advance in implicitly updating L1 / L2 mobility

Abstract

Aspects presented herein may improve latency and efficiency of inter-cell mobility L1 / L2 by providing improved TA management for UEs. In one aspect, a UE derives a TA for a set of deactivated cells based on an Rx time difference between an active cell and the set of deactivated cells. The UE maintains the TA for the set of deactivated cells prior to activation of the set of deactivated cells. The UE applies the TA to the set of deactivated cells or to an initial Tx destined for the set of deactivated cells in response to the activation of the set of deactivated cells. The set of deactivated cells may correspond to a deactivated cell or a deactivated TAG that includes a plurality of deactivated cells.

Description

Technical Field

[0001] The present disclosure relates generally to communication systems, and more particularly to wireless communications with respect to timing advance (TA). Background Art

[0002] Wireless communication systems are widely deployed to provide a variety of telecommunication services, such as telephony, video, data, messaging, and broadcast. Typical wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

[0003] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at a city, country, region, or even global level. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of the continued mobile broadband evolution promulgated by the Third 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). Certain aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. Further improvements to 5G NR technology are needed. In addition, these improvements may also be applicable to other multiple access technologies and telecommunication standards that employ these technologies. Summary of the invention

[0004] A simplified summary of one or more aspects is presented below to provide a basic understanding of these aspects. This summary is not an extensive review of all contemplated aspects. This summary is neither intended to identify key or important elements of all aspects, nor to describe 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 a more detailed description presented later.

[0005] In one aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus derives a timing advance (TA) of a set of deactivated cells based on a receive (Rx) time difference between an active cell and a set of deactivated cells. The apparatus maintains the TA of the set of deactivated cells before activation of the set of deactivated cells. The apparatus applies the TA to the set of deactivated cells or to an initial transmission (Tx) to the set of deactivated cells in response to the activation of the set of deactivated cells.

[0006] To achieve the aforementioned and related purposes, one or more aspects include the features fully described below and particularly pointed out in the claims. The following description and the accompanying drawings set forth in detail some exemplary features of one or more aspects. However, these features are only indicative of only some of the various ways in which the principles of the various aspects can be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network.

[0008] Figure 2A is a diagram illustrating an example of a first frame according to various aspects of the present disclosure.

[0009] Figure 2B is a diagram illustrating an example of downlink (DL) channels within a subframe according to various aspects of the present disclosure.

[0010] Figure 2C is a diagram illustrating an example of a second frame according to various aspects of the present disclosure.

[0011] Figure 2D is a diagram illustrating an example of uplink (UL) channels within a subframe according to various aspects of the present disclosure.

[0012] Figure 3 is a diagram illustrating an example of a base station and a user equipment (UE) in an access network.

[0013] Figure 4 is a diagram illustrating example inter-cell mobility of a UE according to various aspects of the present disclosure.

[0014] Figure 5 is a diagram illustrating example inter-cell mobility of a UE according to various aspects of the present disclosure.

[0015] Figure 6 is a diagram illustrating an example of a UE handing over from one primary cell (PCell) to another candidate PCell in a pre-configured set of candidate PCells according to various aspects of the present disclosure.

[0016] Figure 7 is a diagram illustrating an example of a UE deriving and maintaining a timing advance (TA) of a deactivated cell based on a receive (Rx) time difference measurement according to various aspects of the present disclosure.

[0017] Figure 8 is a diagram illustrating an example of calculating a TA of a second cell based on a TA from a first cell according to various aspects of the present disclosure.

[0018] Fig. 9is a diagram illustrating an example in which a UE according to various aspects of the present disclosure maintains ideal / target metric values ​​for TA and / or UL transmit timing of a set of deactivated cells to ensure that the quality and / or accuracy of the TA and / or UL transmit timing derived for the set of deactivated cells is accurate within a threshold.

[0019] Fig.10 is a flow chart of a method of wireless communication.

[0020] Fig.11 is a flow chart of a method of wireless communication.

[0021] Fig.12 are diagrams illustrating examples of hardware implementations of example devices and / or network entities. DETAILED DESCRIPTION

[0022] Various aspects presented herein can improve the latency and efficiency of L1 / L2 inter-cell mobility by providing improved timing advance (TA) management for UE. In one aspect of the present disclosure, in order to save or reduce the latency of new PCell activation, the UE can be configured to maintain the TA on the deactivated cell or deactivated TAG (which may include multiple deactivated cells), so that the UE can apply the TA associated with the deactivated cell or the deactivated TAG before or when the deactivated cell or deactivated TAG is activated. This can enable the UE to skip requesting / receiving TA updates / commands for the new PCell after the deactivated candidate PCell is selected as the new PCell, thereby improving the latency and efficiency of L1 / L2 inter-cell mobility. For example, the UE can be configured to maintain the TA of a set of deactivated cells (e.g., a deactivated cell or a group of deactivated cells) without specifying any reports and / or TA updates / commands from the serving base station, wherein the UE can derive the TA of the set of deactivated cells based on the receive (Rx) timing difference between the active cell and the set of deactivated cells. Then, once the set of deactivated cells is activated, the UE may autonomously apply the TA derived for the set of deactivated cells. Since the process of maintaining the TA of the set of deactivated cells does not specify additional signaling or reporting between the UE and the base station, the process of maintaining or updating the TA may also be referred to as "reportless TA update".

[0023] The detailed description set forth below in conjunction with the accompanying drawings is a description of various configurations and does not represent the only configurations with which the concepts described herein can be practiced. In order to provide a thorough understanding of the various concepts, the specific embodiments include specific details. However, these concepts can be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid blurring these concepts.

[0024] Several aspects of the telecommunication system are also presented with reference to various apparatus and methods. These apparatus and methods are described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0025] As an example, an element, or any part of an element, or any combination of elements can be implemented as a "processing system", which includes 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, systems on chip (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gate logic components, discrete hardware circuits, and other suitable hardware configured to perform various functionalities described throughout the present disclosure. One or more processors in a 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 meaning instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, processes, functions, or any combination thereof.

[0026] Therefore, in one or more example aspects, specific implementations and / or use cases, the described functions may be implemented with hardware, software, or any combination thereof. If implemented with software, the functions may be stored or encoded as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media. Storage media may be any available medium that can be accessed by a computer. By way of example, such computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of these types of computer-readable media, or any other medium that can be used to store computer-executable code in the form of instructions or data structures that can be accessed by a computer.

[0027] Although various aspects, specific implementations and / or use cases are described in this application by the illustration of some examples, additional or different aspects, specific implementations and use cases may be generated in many different arrangements and scenarios. The various aspects, specific implementations and / or use cases described herein can be implemented across many different platform types, devices, systems, shapes, sizes and packaging arrangements. For example, aspects, specific implementations and / or use cases can be generated via integrated chip specific implementations and other devices based on non-module components (e.g., end-user devices, vehicles, communication equipment, computing equipment, industrial equipment, retail / purchase equipment, medical equipment, artificial intelligence (AI) enabled devices, etc.). Although some examples may be specifically for use cases or applications, or may not be specifically for use cases or applications, the described examples may have a wide range of applicability. Aspects, specific implementations and / or use cases may be in the range from chip-level or modular components to non-modular, non-chip-level specific implementations, and further to the range of aggregated, distributed or original equipment manufacturer (OEM) devices or systems in conjunction with one or more technologies herein. In some practical environments, the equipment in conjunction with the various aspects and features described may also include additional components and features for implementing and practicing the various aspects claimed and described. For example, the transmission and reception of wireless signals necessarily include multiple components for analog and digital purposes (e.g., hardware components including antennas, RF chains, power amplifiers, modulators, buffers, processors, interleavers, adders / accumulators, etc.) The techniques described herein can be practiced in a wide variety of devices of various sizes, shapes, and configurations, chip-level components, systems, distributed arrangements, aggregated or disaggregated components, end-user devices, etc.

[0028] The deployment of a communication system (such as a 5G NR system) can be arranged with various components or constituent parts in a variety of ways. In a 5G NR system or network, a network node, a network entity, a mobility element of a network, a radio access network (RAN) node, a core network node, a network element or a network equipment (such as a base station (BS), or one or more units (or one or more components) that perform base station functionality can be implemented in an aggregated architecture or a decomposed architecture. For example, a BS (such as a Node B (NB), an evolved NB (eNB), an NR BS, a 5G NB, an access point (AP), a transmit receive point (TRP) or a cell, etc.) can be implemented as an aggregated base station (also referred to as an independent BS or a monolithic BS) or a decomposed base station.

[0029] A converged base station may be configured to utilize a radio protocol stack physically or logically integrated within a single RAN node. A decomposed base station may be configured to utilize a protocol stack physically or logically distributed between two or more units, such as one or more central or centralized units (CUs), one or more distributed units (DUs), or one or more radio units (RUs). In some aspects, a CU may be implemented within a RAN node, and one or more DUs may be co-located with the CU, or alternatively, may be geographically or virtually distributed in one or more other RAN nodes. A DU may be implemented to communicate with one or more RUs. Each of a CU, a DU, and a RU may be implemented as a virtual unit, i.e., a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU).

[0030] Base station operation or network design may take into account the aggregated nature of base station functionality. For example, a disaggregated base station may be used in an integrated access backhaul (IAB) network, an open radio access network (O-RAN (network configuration such as that initiated by the O-RAN Alliance)), or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN)). Decomposition may include distributing functionality across two or more units at various physical locations, as well as virtually distributing functionality of at least one unit, which may enable flexibility in network design. Individual units of a disaggregated base station or disaggregated RAN architecture may be configured for wired or wireless communication with at least one other unit.

[0031] Figure 1 1 is a diagram 100 illustrating an example of a wireless communication system and an access network. The illustrated wireless communication system includes a disaggregated base station architecture. The disaggregated base station architecture may include one or more CUs 110 that may communicate directly with a core network 120 via a backhaul link, or indirectly with the core network 120 through one or more disaggregated base station units, such as a near real-time (near RT) RAN intelligent controller (RIC) 125 via an E2 link, or a non-real-time (non-RT) RIC 115 associated with a service management and orchestration (SMO) framework 105, or both. The CU 110 may communicate with one or more DUs 130 via corresponding midhaul links, such as an F1 interface. The DU 130 may communicate with one or more RUs 140 via corresponding fronthaul links. The RU 140 may communicate with corresponding UEs 104 via one or more radio frequency (RF) access links. In some implementations, a UE 104 may be served simultaneously by multiple RUs 140.

[0032] Each of the units (i.e., CU 110, DU 130, RU 140, and near-RT RIC 125, non-RT RIC 115, and SMO framework 105) may include or be coupled to one or more interfaces configured to receive or send signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of these units or an associated processor or controller that provides instructions to the communication interface of these units may be configured to communicate with one or more of the other units via a transmission medium. For example, these units may include a wired interface configured to receive or send signals to one or more of the other units on a wired transmission medium. Additionally, these units may include a wireless interface that may include a receiver, transmitter, or transceiver (such as an RF transceiver) configured to receive or send signals, or both, to one or more of the other units on a wireless transmission medium.

[0033] In some aspects, CU 110 may host one or more higher layer control functions. Such control functions may include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), etc. Each control function may be implemented using an interface that is configured to communicate signals with other control functions hosted by CU 110. CU 110 may be configured to handle user plane functionality (i.e., central unit-user plane (CU-UP)), control plane functionality (i.e., central unit-control plane (CU-CP)), or a combination thereof. In some specific implementations, CU 110 may be logically split into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP unit may communicate bidirectionally with the CU-CP unit via an interface (such as an E1 interface). As needed, CU 110 may be implemented to communicate with DU 130 for network control and signaling.

[0034] DU 130 may correspond to a logical unit that includes one or more base station functions for controlling the operation of one or more RUs 140. In some aspects, DU 130 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, etc.) depending at least in part on a functional split such as that defined by 3GPP. In some aspects, DU 130 may also host one or more low PHY layers. Each layer (or module) may be implemented using an interface that is configured to communicate signals with other layers (and modules) hosted by DU 130 or with control functions hosted by CU 110.

[0035] The lower layer functionality may be implemented by one or more RUs 140. In some deployments, the RU 140 controlled by the 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, etc.), or both, based at least in part on functional splitting (such as lower layer functional splitting). In such an architecture, the RU 140 may be implemented to handle over-the-air (OTA) communications with one or more UEs 104. In some implementations, real-time and non-real-time aspects of control plane and user plane communications with the RU 140 may be controlled by the corresponding DU 130. In some scenarios, this configuration may enable the implementation of the DU 130 and the CU 110 in a cloud-based RAN architecture (such as a vRAN architecture).

[0036] The SMO framework 105 may be configured to support RAN deployment and provisioning of non-virtualized network elements and virtualized network elements. For non-virtualized network elements, the SMO framework 105 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which may be managed via an operation and maintenance interface (such as an O1 interface). For virtualized network elements, the SMO framework 105 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 190) to perform network element lifecycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an 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 specific implementations, the SMO framework 105 may communicate with hardware aspects of the 4G RAN (such as an open eNB (O-eNB) 111) via the O1 interface. Additionally, in some specific implementations, the SMO framework 105 may communicate directly with one or more RUs 140 via the O1 interface. The SMO framework 105 may also include a non-RT RIC 115 configured to support the functionality of the SMO framework 105 .

[0037] The non-RT RIC 115 may be configured to include logic functions that enable non-real-time control and optimization of RAN elements and resources, artificial intelligence (AI) / machine learning (ML) (AI / ML) workflows including model training and updating, or policy-based guidance of applications / features in the near-RT RIC 125. The non-RT RIC 115 may be coupled to or in communication with the near-RT RIC 125 (such as via an A1 interface). The near-RT RIC 125 may be configured to include logic functions that enable near-real-time control and optimization of RAN elements and resources via data collection and actions through an interface (such as via an E2 interface) that connects one or more CUs 110, one or more DUs 130, or both, and O-eNBs with the near-RT RIC 125.

[0038] In some implementations, in order to generate an AI / ML model 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. Such information may be utilized by the near-RT RIC 125 and may be received from a non-network data source or from a network function 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 of performance and employ AI / ML models to perform corrective actions through the SMO framework 105 (such as via reconfiguration of O1) or via the creation of RAN management policies (such as A1 policies).

[0039] At least one of the CU 110, the DU 130, and the RU 140 may be referred to as a base station 102. Therefore, the base station 102 may include one or more of the CU 110, the DU 130, and the RU 140 (each component is indicated by a dotted line to indicate that each component may be included in the base station 102, or may not be included in the base station). The base station 102 provides an access point to the core network 120 for the UE 104. The base station 102 may include a macro cell (a high-power cellular base station) and / or a small cell (a low-power cellular base station). Small cells include femto cells, pico cells, and micro cells. A network including both small cells and macro cells may be referred to as a heterogeneous network. A heterogeneous network may also include a home evolved Node B (eNB) (HeNB), which may provide services to a restricted group referred to as a closed subscriber group (CSG). The communication link between RU 140 and UE 104 may include uplink (UL) (also known as reverse link) transmission from UE 104 to RU 140 and / or downlink (DL) (also known as forward link) transmission from RU 140 to UE 104. The communication link may use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming and / or transmit diversity. The communication link may be through one or more carriers. For each carrier allocated in a carrier aggregation of up to Yx MHz (x component carriers) for transmission in each direction, the base station 102 / UE 104 may use a spectrum of up to Y MHz (e.g., 5MHz, 10MHz, 15MHz, 20MHz, 100MHz, 400MHz, etc.) bandwidth. The carriers may be adjacent to each other or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL ​​compared to UL). The component carrier may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell) and the secondary component carrier may be referred to as a secondary cell (SCell).

[0040] Some UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use DL / UL wireless wide area network (WWAN) spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). The D2D communication may be through a variety of wireless D2D communication systems, such as, for example, Bluetooth, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

[0041] The wireless communication system may also include a Wi-Fi AP 150 that communicates with a UE 104 (also referred to as a Wi-Fi station (STA)) via a communication link 154, for example, in a 5 GHz unlicensed spectrum, etc. When communicating in an unlicensed spectrum, the UE 104 / AP 150 may perform a clear channel assessment (CCA) to determine whether a channel is available prior to communication.

[0042] 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 identified as frequency range designations FR1 (410 MHz-7.125 GHz) and FR2 (24.25 GHz-52.6 GHz). Although a portion of FR1 is greater than 6 GHz, FR1 is often (interchangeably) referred to as the "sub-6 GHz" band in various documents and articles. A similar naming issue sometimes occurs with respect to FR2, which is often (interchangeably) referred to as the "millimeter wave" band in documents and articles, although different from the extremely high frequency (EHF) band (30 GHz-300 GHz) identified as the "millimeter wave" band by the International Telecommunication Union (ITU).

[0043] Frequencies between FR1 and FR2 are generally referred to as mid-band frequencies. Recent 5G NR research has identified the operating bands for these mid-band frequencies as frequency range designation FR3 (7.125GHz-24.25GHz). The bands falling within FR3 can inherit FR1 characteristics and / or FR2 characteristics, so the features of FR1 and / or FR2 can be effectively extended to mid-band frequencies. In addition, higher frequency bands are currently being explored to extend 5G NR operations to more than 52.6GHz. For example, three higher operating bands have been identified as 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.

[0044] In view of the above, unless otherwise specified, if the term "6 GHz or less" is used in this document, it can broadly refer to frequencies that may be less than 6 GHz, may be within FR1, or may include mid-band frequencies. In addition, unless otherwise specified, if the term "millimeter wave" is used in this document, it can broadly refer to frequencies that may include mid-band frequencies, may be within FR2, FR4, FR2-2 and / or FR5, or may be within the EHF band.

[0045] The base station 102 and the UE 104 may each include multiple antennas (such as antenna elements, antenna panels, and / or antenna arrays) to facilitate beamforming. The base station 102 may send a beamformed signal 182 to the UE 104 in one or more transmit directions. The UE 104 may receive the beamformed signal from the base station 102 in one or more receive directions. The UE 104 may also send a beamformed signal 184 to the base station 102 in one or more transmit directions. The base station 102 may receive the beamformed signal from the UE 104 in one or more receive directions. The base station 102 / UE 104 may perform beam training to determine the best receive direction and transmit direction for each of the base station 102 / UE 104. The transmit direction and receive direction of the base station 102 may be the same or different. The transmit direction and receive direction of the UE 104 may be the same or different.

[0046] The base station 102 may include and / or be referred to as a gNB, a Node B, an eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit receive point (TRP), a network node, a network entity, a network equipment, or some other suitable term. The base station 102 may be implemented as an integrated access backhaul (IAB) node, a relay node, a sidelink node, an aggregated (monolithic) base station with a baseband unit (BBU) (including a CU and a DU) and a RU, or as a disaggregated base station including one or more of a CU, a DU, and / or a RU. A set of base stations that may include disaggregated base stations and / or aggregated base stations may be referred to as a next generation (NG) RAN (NG-RAN).

[0047] The core network 120 may include an access and mobility management function (AMF) 161, a session management function (SMF) 162, a user plane function (UPF) 163, a unified data management (UDM) 164, one or more location servers 168, and other functional entities. AMF 161 is a control node that handles signaling between UE 104 and 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 the generation of authentication and key agreement (AKA) credentials, user identity handling, access authorization, and subscription management. One or more location servers 168 are illustrated as including a gateway mobile location center (GMLC) 165 and a location management function (LMF) 166. However, in general, the one or more location servers 168 may include one or more location / positioning servers, which may include one or more of the GMLC 165, the LMF 166, the positioning determination entity (PDE), the serving mobile location center (SMLC), the mobile positioning center (MPC), etc. The GMLC 165 and the LMF 166 support UE location services. The GMLC 165 provides an interface for clients / applications (e.g., emergency services) to access UE positioning information. The LMF 166 receives measurement results and assistance information from the NG-RAN and the UE 104 via the AMF 161 to calculate the positioning of the UE 104. The NG-RAN may determine the positioning of the UE 104 using one or more positioning methods. Positioning the UE 104 may involve signal measurements, positioning estimates, and optional speed calculations based on these measurements. Signal measurements may be performed by the UE 104 and / or the serving base station 102. The measured signals may be based on a satellite positioning system (SPS) 170 (e.g., one or more of a global navigation satellite system (GNSS), a global positioning system (GPS), a non-terrestrial network (NTN), or other satellite positioning / location systems), LTE signals, wireless local area network (WLAN) signals, Bluetooth signals, a terrestrial beacon system (TBS), sensor-based information (e.g., an atmospheric pressure sensor, a motion sensor), an NR enhanced cell ID (NR E-CID) method, NR signals (e.g., multi-round trip time (multi-RTT), DL angle of departure (DL-AoD), DL time difference of arrival (DL-TDOA), UL time difference of arrival (UL-TDOA), and UL angle of arrival (UL-AoA) positioning), and / or one or more of other systems / signals / sensors.

[0048] Examples of UE 104 include cellular phones, smart phones, session initiation protocol (SIP) phones, laptops, personal digital assistants (PDAs), satellite radios, global positioning systems, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, tablet computers, smart devices, wearable devices, vehicles, electric meters, gas pumps, large or small kitchen appliances, healthcare equipment, implants, sensors / actuators, displays, or any other similarly functional devices. Some of the UEs 104 may be referred to as IoT devices (e.g., parking meters, gas pumps, toasters, vehicles, heart monitors, etc.). UE 104 may also be referred to as stations, mobile stations, subscriber stations, mobile units, subscriber units, wireless units, remote units, mobile devices, wireless devices, wireless communication devices, remote devices, mobile subscriber stations, access terminals, mobile terminals, wireless terminals, remote terminals, mobile phones, user agents, mobile clients, clients, or some other suitable terminology. In some scenarios, the term UE may also be applied to one or more supporting devices, such as in a device cluster arrangement. One or more of these devices may access the network collectively and / or individually.

[0049] See again Figure 1 In certain aspects, the UE 104 may be configured to derive a TA for a set of deactivated cells based on an Rx time difference between an active cell and the set of deactivated cells; maintain the TA for the set of deactivated cells prior to activation of the set of deactivated cells; and apply the TA to the set of deactivated cells or to an initial Tx to the set of deactivated cells in response to the activation of the set of deactivated cells (e.g., via the TA derivation component 198).

[0050] Figure 2A FIG200 is a diagram illustrating an example of a first subframe within a 5G NR frame structure. Figure 2B FIG230 is a diagram illustrating an example of DL channels within a 5G NR subframe. Figure 2C FIG250 is a diagram illustrating an example of a second subframe within a 5G NR frame structure. Figure 2D FIG280 is a diagram illustrating an example of UL channels within a 5G NR subframe. The 5G NR frame structure may be frequency division duplex (FDD), where for a particular set of subcarriers (carrier system bandwidth), subframes within that subcarrier set are dedicated to either DL or UL, or may be time division duplex (TDD), where for a particular set of subcarriers (carrier system bandwidth), subframes within that subcarrier set are dedicated to both DL and UL. Figure 2A , Figure 2CIn the example provided, 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 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 may be configured with any of the various available slot formats 0 to 61. Slot formats 0 and 1 are both DL and both UL, respectively. Other slot formats 2-61 include a mix of DL, UL, and flexible symbols. The slot format is configured for the UE via a received slot format indicator (SFI) (dynamically configured via DL control information (DCI) or semi-statically / statically configured via radio resource control (RRC) signaling). Note that the following description also applies to the 5G NR frame structure as TDD.

[0051] FIG. 2A to FIG. 2D The frame structure is illustrated, and various aspects of the present disclosure may be applicable to other wireless communication technologies that may have different frame structures and / or different channels. A frame (10ms) may be divided into 10 subframes of the same size (1ms). Each subframe may include one or more time slots. A subframe may also include a microslot, 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 conventional or extended. For a conventional CP, each time slot may include 14 symbols, and for an extended CP, each time slot may include 12 symbols. The symbol on the DL may be a CP orthogonal frequency division multiplexing (OFDM) (CP-OFDM) symbol. The symbol on the UL may be a CP-OFDM symbol (for high throughput scenarios) or a discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbol (also known as a single carrier frequency division multiple access (SC-FDMA) symbol) (for power-limited scenarios; limited to single-stream transmission). The number of time slots within a subframe is based on the CP and parameter set. The numerology defines the subcarrier spacing (SCS) (see Table 1). The symbol length / duration can be scaled with 1 / SCS.

[0052]

[0053] Table 1: Parameter set, SCS and CP

[0054] For normal CP (14 symbols / slot), different parameter sets μ0 to 4 allow 1, 2, 4, 8, and 16 slots per subframe, respectively. For extended CP, parameter set 2 allows 4 slots per subframe. Accordingly, for normal CP and parameter set μ, there are 14 symbols / slot and 2 μ timeslots / subframe. The subcarrier spacing can be equal to 2 μ*15kHz, where μ is parameter set 0 to 4. Therefore, the subcarrier spacing for parameter set μ=0 is 15kHz, and the subcarrier spacing for parameter set μ=4 is 240kHz. The symbol length / duration is inversely related to the subcarrier spacing. FIG. 2A to FIG. 2D An example of a parameter set μ=2 with a normal CP of 14 symbols per slot and 4 slots per subframe is provided. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is about 16.67 μs. Within a frame set, there may be one or more different bandwidth parts (BWPs) that are frequency-division multiplexed (see Figure 2B ). Each BWP may have a specific parameter set and CP (normal or extended).

[0055] A resource grid may be used to represent the frame structure. Each slot includes a resource block (RB) (also referred to as a physical RB (PRB)) extending over 12 consecutive subcarriers. The resource grid is divided into a number of resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0056] like Figure 2A As illustrated, some of the REs carry reference (pilot) signals (RS) for the UE. The RS may include a demodulation RS (DM-RS) (indicated as R for a particular configuration, but other DM-RS configurations are possible) and a channel state information reference signal (CSI-RS) for channel estimation at the UE. The RS may also include a beam measurement RS (BRS), a beam refinement RS (BRRS), and a phase tracking RS (PT-RS).

[0057] Figure 2BExamples of various DL channels within a subframe of a frame are illustrated. A physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) (e.g., 1, 2, 4, 8, or 16 CCEs), each CCE including six RE groups (REGs), each REG including 12 consecutive REs in an OFDM symbol 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 a PDCCH monitoring opportunity on a CORESET, wherein the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs may be located at higher and / or lower frequencies on the channel bandwidth. A primary synchronization signal (PSS) may be within symbol 2 of a particular subframe of a frame. The PSS is used by UE 104 to determine subframe / symbol timing and physical layer identification. A secondary synchronization signal (SSS) may be within symbol 4 of a particular subframe of a frame. The SSS is used by the UE to determine the physical layer cell identity group number and the radio frame timing. Based on the physical layer identity and the physical layer cell identity 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 referred to as an SS block (SSB)). The MIB provides the system frame number (SFN) and the number of RBs in the system bandwidth. The physical downlink shared channel (PDSCH) carries user data, broadcast system information such as system information blocks (SIBs) that are not sent via the PBCH, and paging messages.

[0058] like Figure 2C As illustrated, some of the REs carry DM-RS (indicated as R for a particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE may send a DM-RS for a physical uplink control channel (PUCCH) and a DM-RS for a physical uplink shared channel (PUSCH). The PUSCH DM-RS may be sent in the first or first two symbols of the PUSCH. Depending on whether a short PUCCH or a long PUCCH is sent and depending on the specific PUCCH format used, different configurations may be used to send the PUCCH DM-RS. The UE may send a sounding reference signal (SRS). The SRS may be sent in the last symbol of a subframe. The SRS may have a comb structure, and the UE may send the SRS on one of the teeth of the comb. The SRS may be used by the base station for channel quality estimation to achieve frequency-dependent scheduling of the UL.

[0059] Figure 2DExamples of various UL channels within a subframe of a frame are illustrated. The PUCCH may be located at a position as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicators (CQI), precoding matrix indicators (PMI), rank indicators (RI), and hybrid automatic repeat request (HARQ) acknowledgement (ACK) (HARQ-ACK) feedback (i.e., one or more HARQ ACK bits indicating one or more ACKs and / or negative ACKs (NACKs)). The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0060] Figure 3 3 is a block diagram of a base station 310 communicating with a UE 350 in an access network. In the DL, Internet Protocol (IP) packets may be provided to a controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller / processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with delivery of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation and reassembly of RLC service data units (SDUs), re-segmentation 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 through HARQ, priority handling, and logical channel prioritization.

[0061] The 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) coding / decoding of the transport channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 handles the mapping to 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. Subsequently, each stream can be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., a pilot) in the time domain and / or frequency domain, and then combined using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to generate multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation schemes, as well as for spatial processing. Channel estimates may be derived from reference signals and / or channel state feedback sent by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318Tx. Each transmitter 318Tx may modulate a radio frequency (RF) carrier with a corresponding spatial stream for transmission.

[0062] At the UE 350, each receiver 354Rx receives a signal through its corresponding antenna 352. Each receiver 354Rx recovers the information modulated onto the RF carrier and provides the information to a receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they can be merged into a single OFDM symbol stream by the RX processor 356. The RX processor 356 then converts the OFDM symbol stream from the time domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier and the reference signal are recovered and demodulated by determining the most likely signal constellation point sent by the base station 310. These soft decisions can be based on channel estimates calculated by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally sent on the physical channel by the base station 310. The data and control signals are then provided to the controller / processor 359, which implements layer 3 and layer 2 functionality.

[0063] The controller / processor 359 may be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport channels and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets. The controller / processor 359 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operations.

[0064] Similar to the functions described in conjunction with DL transmissions performed by the base station 310, the controller / processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functionality associated with header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functionality associated with delivery of upper layer PDUs, error correction through 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 onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0065] The TX processor 368 may use channel estimates derived by the channel estimator 358 from a reference signal or feedback sent by the base station 310 to select appropriate coding and modulation schemes and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via corresponding transmitters 354Tx. Each transmitter 354Tx may modulate an RF carrier with a corresponding spatial stream for transmission.

[0066] UL transmissions are processed at the base station 310 in a manner similar to that described in conjunction with the receiver functionality at the UE 350. Each receiver 318Rx receives a signal through its corresponding antenna 320. Each receiver 318Rx recovers information modulated onto an RF carrier and provides the information to the RX processor 370.

[0067] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport channels and logical channels, packet reassembly, decryption, header decompression, control signal processing to recover IP packets. The controller / processor 375 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operations.

[0068] At least one of the TX processor 368, the RX processor 356, and the controller / processor 359 may be configured to perform operations related to Figure 1 The TA derivation component 198 combines various aspects.

[0069] Figure 4 4 is a diagram illustrating example inter-cell mobility of a UE according to various aspects of the present disclosure. When a UE 402 moves from one location to another, the UE 402 may be configured to perform inter-cell mobility based on layer 1 (L1) (e.g., physical layer) and / or layer 2 (L2) (e.g., medium access control (MAC) layer) (which may also be referred to as "L1 / L2 mobility" hereinafter). Under inter-cell mobility, the UE 402 may be connected to a base station 404 (e.g., via a distributed unit (DU) of the base station 404), and the UE 402 may be handed over from one cell (or a group of cells) to another cell (or another group of cells) without implementing a radio resource control (RRC) anchor change (e.g., the UE 402 maintains its connection with the base station 404).

[0070] As shown at 406, in order to enable UE 402 to perform L1 / L2 mobility, base station 404 may configure a set of cells (e.g., cells 1 to 7) for UE 402 via RRC configuration, and the set of cells may be referred to as an L1 / L2 mobility configured cell set (or simply a configured cell set). Each cell having a configured cell set may be referred to as a configured cell. The L1 / L2 mobility configured cell set may also include an L1 / L2 mobility activated cell set (or simply an activated cell set) and an L1 / L2 mobility deactivated cell set (or simply a deactivated cell set). As shown at 408, the activated cell set may refer to a group of cells (e.g., activated cells 2 and 4) in the configured cell set that are activated and can be immediately used for data and control transfer between UE 402 and base station 404. On the other hand, as shown at 410, the deactivated cell set may refer to a group of cells (e.g., deactivated cells 1, 4, 5, 6, and 7) in the configured cell set that are deactivated and may be immediately activated (e.g., become part of the activated cell set) via L1 / L2 signaling (but may not be immediately available for data and control transfer before being activated). The cells in both the activated cell set and the deactivated cell set may be considered as serving cells under L1 / L2 mobility, and each cell may include multiple component carriers (CCs). The cells in the configured cell set may belong to the same DU or different DUs. The base station 404 may continue to actively configure a new cell set for the UE 402 via RRC signaling based on the mobility of the UE 402 (e.g., by adding cells to the configured cell list and / or removing cells from the configured cell list).

[0071] To facilitate seamless mobility within cells in the activated cell set (which may be referred to as activated cells), L1 / L2 signaling may be used between UE 402 and base station 404 to activate / deactivate cells in the configured cell set and select beams within the activated cells. In other words, mobility management of the activated cell set and the deactivated cell set may be based on L1 / L2 signaling rather than layer 3 (L3) (e.g., network layer, i.e., RRC) signaling, because L1 / L2 signaling generally requires less time to execute than L3 signaling. Therefore, when UE 402 moves, cells from the configured cell set may be deactivated and activated via L1 / L2 signaling. For example, as Figure 5 As shown in diagram 500 , after UE 402 moves to another location, cell 4 may be activated via L1 / L2 signaling between UE 402 and base station 404 and cell 2 may be deactivated via the signaling.

[0072] In some examples, inter-cell mobility can be based on signal quality (e.g., measurements such as reference signal received power (RSRP), signal to interference plus noise ratio (SINR), etc.) and / or based on the load of the cell. In some configurations, the cells in the L1 / L2 mobility configured cell set can belong to the same DU, which can be similar to carrier aggregation (CA), but these cells can be located on the same carrier frequency. In most implementations, the configured cell set configured for the UE 402 is large enough to cover a meaningful mobility area.

[0073] A subset of deactivated cells (which may be referred to as a candidate cell set) may be provided to UE 402, which UE 402 may autonomously select to add to the activated cell set, such as based on measured channel quality, load information, etc. Figure 4 As shown in the diagram 400 of FIG. 4 , a deactivated cell set including deactivated cells 1, 4, 5, 6, and 7 may be provided to UE 402. Then, as shown in FIG. Figure 5 As shown in diagram 500 of , when UE 402 moves, UE 402 can measure and determine that the channel quality of activated cell 2 has dropped below the signal threshold or has a high traffic load (e.g., the number of connected users exceeds the traffic threshold). In response, UE 402 can autonomously add deactivated cell 4 to the activated cell set. In some examples, this can be similar to conditional handover to quickly and efficiently add prepared cells.

[0074] Re-reference Figure 4 , as shown at 412, a RU (e.g., in conjunction with a DU) connected to the base station 404 Figure 1 Each RU in the described RU 140 may have multi-carrier (eg, N CC) support, where each CC is a cell. Therefore, activation / deactivation of cells may be performed based on carrier (eg, cell) groups.

[0075] To manage the primary cell (PCell), the UE 402 and the base station 404 may also use L1 / L2 signaling to set the PCell from one or more pre-configured options within the set of activated cells. For some networks, when the new PCell is not from the set of activated cells for L1 / L2 mobility, L3 mobility (e.g., L3 signaling) may be used for PCell changes (e.g., L3 handovers), where RRC signaling may be used to update the set of cells for L1 / L2 mobility at the time of L3 handovers. For purposes of this disclosure, a special cell (SpCell / spCell / sPCell) may include a PCell or a primary secondary cell (PSCell) (e.g., SpCell=PCell or PSCell). In addition, an activated cell may also be referred to as an active cell.

[0076] Figure 6 600 is a diagram illustrating an example of a UE handing over from one PCell to another candidate PCell in a pre-configured set of candidate PCells according to various aspects of the present disclosure. The UE 602 may be configured with a set of candidate PCells by a base station, such as in conjunction with Figure 4 and Figure 5 Described. In some examples, each PCell in the set of candidate PCells may also be associated with a timing advance group (TAG). For the purposes of the present disclosure, a TAG may include one or more serving cells having the same uplink TA and the same downlink timing reference cell. Each TAG may include at least one serving cell with a configured uplink, and the mapping of each serving cell to the TAG may be configured by the base station via RRC. In addition, a deactivated TAG may refer to a TAG that includes only deactivated cells (e.g., no activated / active cells), and an active TAG or activated TAG may refer to a TAG that includes at least one activated / active cell.

[0077] When UE 602 moves, the base station may hand over UE 602 from the current PCell 604 (which may be associated with a first TAG (e.g., TAG0) or a first TA) to a new PCell 606 in a set of deactivated candidate PCells, where the new PCell 606 may be associated with a second TAG (e.g., TAG 1) or a second TA. For example, the base station may request UE 602 to measure the set of deactivated candidate PCells and report the measurements to the base station (e.g., via a CSI report). Based on the measurements, the base station may determine which deactivated candidate PCell to hand over UE 602. In other words, for L1 / L2 mobility, when the UE moves, the PCell may be reselected / updated in a set of pre-configured deactivated candidate PCells for the UE based on the UE's L1 measurements of those deactivated candidate PCells.

[0078] Therefore, before one of the candidate deactivated PCells is selected as the new PCell, these candidate deactivated PCells may not be activated. For example, before being selected as the new PCell, the new PCell 606 may not be activated. In some examples, where a TAG is assigned to each deactivated candidate PCell, there may be other cells sharing the same TAG. For example, the candidate cells in a candidate cell group (e.g., PCells and SCells) may be associated with a physical cell site, where all candidate cells in the same TAG may have been previously deactivated (e.g., all candidate cells sharing TAG 1 with the new PCell 606 were not activated before handover).

[0079] Various aspects presented herein can improve the latency and efficiency of L1 / L2 inter-cell mobility by providing improved timing advance (TA) management for UEs. In one aspect, when a UE is handed over from an activated PCell to a deactivated candidate PCell, it may be beneficial for the UE to maintain the TA on the deactivated candidate PCell to save or reduce the latency of new PCell activation. For example, after the deactivated candidate PCell is selected as the new PCell, the UE may skip requesting a TA update. For the purposes of this disclosure, TA may refer to an offset or time value that a UE can apply to its uplink transmission so that the uplink transmission can be synchronized with another transmission (e.g., a downlink transmission). For example, a UE may receive a TA command from a base station, wherein the TA command may request the UE to adjust its uplink transmission so that the UE transmits uplink symbols (e.g., for transmitting PUSCH, PUCCH and / or SRS transmissions, etc.) in advance according to the TA command. In other words, the TA command may notify the UE of the amount of time it will advance its uplink transmission.

[0080] In some network implementations, the UE may be configured not to send PRACH, Sounding Reference Signal (SRS), and Physical Uplink Control Channel (PUCCH) on a deactivated PSCell / SCell, not to receive Physical Downlink Control Channel (PDCCH) on or for a deactivated PCell / SCell, and / or not to report CSI for a deactivated PCell / SCell. As a result, the UE may not be aware of the TA associated with the deactivated PSCell / SCell until the deactivated PSCell / SCell is activated. For example, referring back to Figure 6, before the UE 602 is connected to the new PCell 606 or before the UE 602 receives a TA update / command for the new PCell 606 from the base station, the UE 602 may not know the TA associated with the new PCell 606. Therefore, after the new PCell 606 is activated for the UE 602, it may take some time for the UE 602 to receive and apply the TA associated with the new PCell 606.

[0081] In one aspect of the present disclosure, in order to save or reduce the latency of activating a new PCell, the UE may be configured to maintain the TA on a deactivated cell or a deactivated TAG (which may include multiple deactivated cells), so that the UE may apply the TA associated with the deactivated cell or the deactivated TAG before or when the deactivated cell or the deactivated TAG is activated. This may enable the UE to skip requesting / receiving a TA update / command for the new PCell after the deactivated candidate PCell is selected as the new PCell, thereby improving the latency and efficiency of L1 / L2 inter-cell mobility. For example, the UE may be configured to maintain the TA of a set of deactivated cells (e.g., a deactivated cell or a group of deactivated cells) without specifying any reports and / or TA updates / commands from a serving base station, wherein the UE may derive the TA of the set of deactivated cells based on the receive (Rx) timing difference between the active cell and the set of deactivated cells. Then, once the set of deactivated cells is activated, the UE may autonomously apply the TA derived for the set of deactivated cells. Since the process of maintaining the TA of the set of deactivated cells does not specify additional signaling or reporting between the UE and the base station, the process of maintaining or updating the TA may also be referred to as "report-free TA update". For the purposes of this disclosure, the Rx timing difference may refer to the time difference between receiving a signal from a first wireless device (e.g., from a first cell) and receiving a signal from a second wireless device (e.g., from a second cell).

[0082] In another example, the UE may be configured to report the Rx timing difference between different cells to the base station, and the base station may derive at least the TA of the deactivated cell and indicate the derived TA to the UE for UE application. In other words, the TA may be calculated by the base station based on the UE report of the Rx timing difference. In the context of L1 / L2 mobility, the UE may report the Rx timing difference between the active cell and the deactivated cell, and the base station may calculate the TA of the deactivated cell and signal the calculated TA to the UE once the cell is activated. This process of maintaining or updating the TA may be referred to as "report-based TA update".

[0083] In one aspect, the reportless TA update for deactivated cells may include the following differences compared to the report-based TA update. In one example, there may be no dynamic signaling, or the amount of signaling may be reduced for the reportless TA update (e.g., no UL reports and TA commands, etc.). For example, it is possible to update the TA of a cell without any resource and / or reporting configuration. In another example, the base station may only provide semi-static information to the UE for the UE to derive the actual TA, such as the transmit (Tx) timing difference between two cells, the UL to DL timing difference at each cell (e.g., the time difference between an uplink radio frame and a corresponding downlink radio frame), etc. In another example, a set of rules may be specified at the UE to adjust the UE TA update period, wherein the set of rules may ensure that the TA is updated frequently enough at the UE in the absence of reports. In another example, one or more formats for the stored TA and / or the applied implicit update TA may be defined or configured at the UE. For example, when a TA is stored for a deactivated cell / TAG and applied upon activation, a unit of TA may be specified for the UE.

[0084] Figure 7 700 is a diagram illustrating an example of a UE deriving and maintaining a TA of a deactivated cell based on Rx time difference measurement (which may be referred to as "implicit TA update") according to various aspects of the present disclosure. In one example, when a physical random access channel (PRACH) is not transmitted on a deactivated cell or deactivated TAG, the UE may derive the TA based on receiving a TA command from a reference active cell and calculating the Rx timing difference between the reference active cell and a set of deactivated cells in a pair of active and deactivated TAGs, respectively, thereby maintaining the corresponding TA of the deactivated cell or deactivated TAG.

[0085] For example, in order to enable UE 702 to perform L1 / L2 mobility, serving base station 704 may configure an L1 / L2 mobility configuration cell set for UE 702, wherein the L1 / L2 mobility configuration cell set may include at least an activated cell set (which may include active cell 706) and a deactivated cell set (which may include a set of deactivated cells 708), such as in combination with Figure 4 and Figure 5As described. The activated cell set may refer to a group of cells that are activated in the L1 / L2 mobility configuration cell set and can be immediately used for data and control transfer between the UE 702 and the base station 704. On the other hand, the deactivated cell set may refer to a group of cells that are deactivated in the L1 / L2 mobility configuration cell set and can be immediately activated (e.g., become part of the active cell set) through L1 / L2 signaling (but may not be immediately used for data and control transfer before being activated). The cells in both the activated cell set and the deactivated cell set can be regarded as serving cells under L1 / L2 mobility, and each cell may include multiple CCs.

[0086] In one aspect, as shown at 714, the UE 702 may be configured to derive a TA 710 for the set of deactivated cells 708 based on an Rx time difference between the active cells 706 and the set of deactivated cells 708. For example, the UE 702 may receive a synchronization signal block (SSB) or a reference signal (RS) transmitted from the set of deactivated cells 708 and / or the active cells 706, and the UE 702 may derive the TA for the set of deactivated cells 708 based at least in part on the DL Rx timing and the DL Tx timing of the active cells 706 and the set of deactivated cells 708. The UE 702 may then maintain the derived TA 710 for the set of deactivated cells 708 prior to activation of the set of deactivated cells 708, and the UE 702 may apply the TA 710 to the set of deactivated cells 708 (when the set of deactivated cells 708 is not activated) and / or to initial transmissions to the set of deactivated cells 708 (after the set of deactivated cells 708 is activated) (discussed in detail below). For purposes of the present disclosure, the set of deactivated cells 708 may include only one deactivated cell or multiple deactivated cells (e.g., a deactivated TAG).

[0087] Figure 8 8 is a diagram illustrating an example of calculating a TA for a second cell (eg, a set of deactivated cells 708) based on a TA from a first cell (eg, an active cell 706) in accordance with various aspects of the present disclosure. Figure 7 712, UE 702 may receive a TA associated with active cell 706 from active cell 706, such as via a TA command. For purposes of illustration, the TA associated with active cell 706 may be referred to as T1, and the TA 710 derived for the set of deactivated cells 708 may be referred to as T2.

[0088] In one aspect, referring to Figure 8 , UE 702 may calculate TA 710 (eg, T2) based on the following equation:

[0089] T2=T1–2*(R1-R2)+[2*(S1-S2)-(Q1-Q2)],

[0090] Wherein, T1 corresponds to the TA of the UE 702 for the active cell 706 (eg, which may be signaled by the active cell 706, such as Figure 7 712 of the UE 702), R1 corresponds to the DL Rx timing of the active cell 706, R2 corresponds to the DL Rx timing of the set of deactivated cells 708, S1 corresponds to the DL Tx timing of the active cell 706, S2 corresponds to the DL Tx timing of the set of deactivated cells 708, Q1 corresponds to the UL and DL timing difference of the active cell 706, and Q2 corresponds to the UL and DL timing difference of the set of deactivated cells 708. In addition, the UL transmission timing of the UE 702 for the active cell 706 (which may be indicated as U1) and the UL transmission timing of the UE 702 for the set of deactivated cells 708 (which may be indicated as U2) may be defined as:

[0091] U1=R1–T1,

[0092] U2=R2–T2, and

[0093] U2=R2–T1+2*(R1–R2)-[2*(S1-S2)-(Q1-Q2)].

[0094] In another aspect of the present disclosure, in order to ensure the quality and / or accuracy of the TA 710 derived by the UE 702 for the set of out-of-cells 708 (i.e., implicitly updating the TA quality), a set of specifications may be defined for the UE 702 and applied by the UE. For example, the specifications may be defined at the UE 702 so that the metrics applied by the UE 702 can achieve a certain accuracy or accuracy threshold compared to the ideal value metric. The applied metrics related to the UE 702 applying the TA 710 (i.e., implicit TA update) may include the following cases.

[0095] In the first case (e.g., case 1), the UE 702 may derive and maintain the TA 710 (e.g., T2) or UL transmission timing (e.g., U2) of the set of deactivated cells 708 before activation of the set of deactivated cells 708, so that once the set of deactivated cells 708 is activated, the UE 702 may apply the TA 710 to UL Tx to the set of deactivated cells 708. In other words, the TA or UL transmission timing is applied to the deactivated cell / TAG to prepare for UL Tx after the deactivated cell / TAG is activated. In this case, although UL Tx does not occur, the UE 702 may still adjust the UL Tx timing.

[0096] In the second case (e.g., case 2), the UE 702 may derive, maintain, and apply a TA 710 (e.g., T2) or UL transmit timing (e.g., U2) to the initial UL Tx to the set of deactivated cells 708 after the set of deactivated cells 708 is activated. In other words, the TA or UL transmit timing is applied to the initial UL Tx on the newly activated cell / TAG. The initial UL Tx to the set of deactivated cells 708 may include at least those cells to which the TA may be applied. In one example, the UE 702 may be configured to derive the TA 710 or UL transmit timing and apply it to the initial UL Tx (e.g., to apply case 2) when at least one SSB is available at the UE 702 during a defined period, such as during the last X ms (e.g., X=160). In other words, if the UE 702 is able to receive at least one SSB from the set of deactivated cells 708 before a defined period (e.g., X ms), the UE 702 may derive the TA 710 or UL transmission timing (e.g., U2) after the set of deactivated cells 708 is activated and apply it to the initial UL Tx to the set of deactivated cells 708. Compared to Case 1, this may reduce TA processing and maintenance at the UE 702.

[0097] Fig. 9 Schematic diagram 900 illustrating an example in which a UE according to various aspects of the present disclosure maintains ideal / target metric values ​​for TA and / or UL transmit timing for a set of deactivated cells (e.g., a set of deactivated cells 708) to ensure that the quality and / or accuracy of the TA (e.g., TA 710) and / or UL transmit timing derived for the set of deactivated cells is accurate within a threshold.

[0098] For example, as shown at 902, the UE 702 may be configured to maintain or calculate an ideal or target metric value for a TA (e.g., T2) and / or UL transmit timing (e.g., U2) for a set of deactivated cells 708, such as based on the following equation:

[0099] T2 = T1 – 2*(R1-R2) + [2*(S1-S2)-(Q1-Q2)], and

[0100] U2=R2–T1+2*(R1–R2)-[2*(S1-S2)-(Q1-Q2)].

[0101] Then, if the TA 710 or UL transmit timing (represented by T2' and U2', respectively, for this example) derived by the UE 702 for the set of deactivated cells 708 exceeds a defined threshold or timing accuracy specification (e.g., exceeds a UL Tx timing error defined for the set of deactivated cells 708 as shown at 904), the UE 702 may be prevented from applying the derived TA 710 (T2') or UL transmit timing (U2') to the set of deactivated cells 708.

[0102] In one aspect, the timing accuracy specification (e.g., a defined threshold) to be met by the UE 702 (so that the UE 702 applies the maintained TA 710) can be expressed in the form of plus or minus (±) X*64*Tc, where X can be fixed or depend on one or more factors, and Tc can be a time unit (e.g., Tc=0.509 nanoseconds (ns)). For example, the one or more factors can include a frequency range in which the UE 702 will communicate with the base station 704, where if the UE 702 will communicate in the frequency range FR1, a first value can be assigned to X, if the UE 702 will communicate in the frequency range FR2-1, a second value can be assigned to X, and if the UE 702 will communicate in the frequency range FR2-2, a third value can be assigned to X, and so on.

[0103] In another example, the one or more factors may include a DL RS configured for the UE 702 or a DL SCS of a DL active / configured BWP. If the UE 702 is configured to maintain the TA 710 of the set of deactivated cells 708 before activation of the set of deactivated cells 708 (e.g., case 1 is applied), the DL SCS may include the SCS of the DL RS of one or both of the active cells 706 and the set of deactivated cells 708 used by the UE 702 for DL ​​Tx timing difference measurement. On the other hand, if the UE 702 is configured to derive the TA 710 after the set of deactivated cells 708 is activated and apply it to the initial UL Tx to the set of deactivated cells 708 (e.g., case 2 is applied), the DL SCS may be the SSB of the set of deactivated cells 708 (i.e., the newly activated cell / TAG) after activation or the SCS of the active DL BWP.

[0104] In another example, the one or more factors may include a UL channel / RS or a UL SCS of an UL active / configured BWP configured for the UE 702. If the UE 702 is configured to maintain the TA 710 of the set of deactivated cells 708 before activation of the set of deactivated cells 708 (e.g., case 1 is applied), the UL SCS may be the maximum SCS of all configured UL BWPs in the cells to which the TA 710 is applied. On the other hand, if the UE 702 is configured to derive the TA 710 after the set of deactivated cells 708 is activated and apply it to the initial UL Tx to the set of deactivated cells 708 (e.g., case 2 is applied), the UL SCS may be the SCS of the initial UL Tx to the set of deactivated cells 708 (e.g., to the newly activated cell / TAG).

[0105] In another example, the one or more factors may include a link quality (e.g., L1-RSRP and / or SINR) between the UE 702 and the cell. If the UE 702 is configured to maintain the TA 710 of the set of deactivated cells 708 before activation of the set of deactivated cells 708 (e.g., case 1 is applied), the link quality may include the quality of the DL RS of one or both of the active cells 706 and the set of deactivated cells 708 used by the UE 702 for DL ​​Tx timing difference measurement. On the other hand, if the UE 702 is configured to derive the TA 710 after the set of deactivated cells 708 is activated and apply it to the initial UL Tx to the set of deactivated cells 708 (e.g., case 2 is applied), the link quality may include the quality of the SSB of the set of deactivated cells 708 (e.g., to the newly activated cell / TAG).

[0106] In another aspect of the present disclosure, if the TA 710 derived / maintained by the UE 702 cannot meet or comply with the timing accuracy specification (e.g., a defined threshold), in one example, the UE 702 may be configured to gradually adjust the applied TA 710 or UL Tx timing until the timing accuracy specification is met / complied. In addition, the gradual adjustment may have the following parameters (whose values ​​may also depend on the frequency range and / or UL SCS): the maximum amount of timing change amplitude in one adjustment (e.g., 1 ms, 2 ms, etc.), the minimum aggregate adjustment rate per second, the maximum aggregate adjustment rate for a defined period (e.g., every X ms), or a combination thereof. In another example, the UE 702 may be configured to perform a one-time adjustment of the TA 710 to comply with the timing accuracy specification (e.g., a defined threshold), wherein the UE 702 may skip applying the TA 710 to the set of deactivated cells 708. In some examples, such a one-time adjustment may be affected by the capabilities of the UE 702, the frequency range in which the UE 702 is communicating, and / or the power class of the UE 702, etc.

[0107] Fig.10 1000 is a flow chart of a method of wireless communication. The method may be performed by a UE (eg, UE 104, 402, 602, 702; device 1204). The method may enable the UE to maintain a TA on a set of deactivated candidate PCells to save or reduce new PCell activation delay.

[0108] At 1002, the UE may receive a TA command from an active cell, wherein the TA command indicates a second TA of the active cell, and the UE may calculate an Rx time difference between the active cell and a set of deactivated cells based on the second TA, such as in combination with Figure 7 and 8 For example, at 712, UE 702 may receive a TA command including a TA of active cell 706 from active cell 706, and UE 702 may calculate an Rx time difference between active cell 706 and a set of deactivated cells 708 based on the TA of active cell 706. Receipt of a TA command and / or calculation of an Rx time difference may be performed by, for example Fig.12 The TA derivation component 198, the cellular baseband processor 1224 and / or the transceiver 1222 of the device 1204 are executed.

[0109] In one example, the TA of the set of deactivated cells is derived based on the following equation: T2=T1-2*(R1-R2)+[2*(S1-S2)-(Q1-Q2)], where T2 corresponds to the TA, T1 corresponds to the second TA, R1 corresponds to the first downlink (DL) Rx timing of the active cell, R2 corresponds to the second DL Rx timing of the set of deactivated cells, S1 corresponds to the first DL Tx timing of the active cell, S2 corresponds to the second DL Tx timing of the set of deactivated cells, Q1 corresponds to the first UL and DL timing difference of the active cell, and Q2 corresponds to the second UL and DL timing difference of the set of deactivated cells. In such an example, the first UL transmit timing (U1) of the active cell is determined based on the following equation: U1=R1-T1. In such examples, the second UL transmission timing (U2) of the set of deactivated cells is determined based on the following equation: U2=R2-T2; or U2=R2-T1+2*(R1-R2)-[2*(S1-S2)-(Q1-Q2)].

[0110] At 1004, the UE may derive the TA of the set of deactivated cells based on the Rx time difference between the active cell and the set of deactivated cells, such as in combination with Figure 7 and 8 For example, at 714, UE 702 may derive TA 710 for the set of deactivated cells 708 based on the Rx time difference between active cell 706 and the set of deactivated cells 708. The derivation of the TA for the set of deactivated cells may be performed by, for example Fig.12 The TA derivation component 198, the cellular baseband processor 1224 and / or the transceiver 1222 of the device 1204 are executed.

[0111] In an example, the set of deactivated cells corresponds to one deactivated cell or a deactivated TAG including a plurality of deactivated cells.

[0112] In another example, the UE may receive at least one of a Tx timing difference between the active cell and the set of deactivated cells or a UL-to-DL timing difference of each of the active cell and the set of deactivated cells from the network node, wherein the TA of the set of deactivated cells is further derived based on the Tx timing difference or the UL-to-DL timing difference.

[0113] At 1006, the UE may maintain the TA of the set of deactivated cells prior to activation of the set of deactivated cells, such as in conjunction with Figure 7 and Figure 8 For example, UE 702 may maintain TA 710 for the set of deactivated cells 708 prior to activation of the set of deactivated cells 708. The maintenance of the TA may be performed by, for example Fig.12The TA derivation component 198, the cellular baseband processor 1224 and / or the transceiver 1222 of the device 1204 are executed.

[0114] At 1008, the UE may apply the TA to the set of deactivated cells or to initial Tx to the set of deactivated cells in response to the activation of the set of deactivated cells, such as in conjunction with Figure 7 and Figure 8 For example, UE 702 may apply TA 710 to the set of deactivated cells 708 or to initial Tx to the set of deactivated cells 708 in response to the activation of the set of deactivated cells 708. Applying the TA to the set of deactivated cells or to initial Tx to the set of deactivated cells may be performed by, for example Fig.12 The TA derivation component 198, the cellular baseband processor 1224 and / or the transceiver 1222 of the device 1204 are executed.

[0115] In one example, at 1010, the UE may determine whether the derived TA is within a timing accuracy threshold, wherein based on the derived TA satisfying the timing accuracy threshold, the TA is applied to the set of deactivated cells or to the initial Tx to the set of deactivated cells, such as in conjunction with Figures 7 to 9 For example, UE 702 may determine whether the derived TA 710 is within a timing accuracy threshold, and if TA 710 satisfies the timing accuracy threshold, UE 702 may apply TA 710 to the set of deactivated cells 708 or to the initial Tx to the set of deactivated cells 708. The determination of whether the derived TA is within the timing accuracy threshold may be performed by, for example Fig.12 The TA derivation component 198, the cellular baseband processor 1224 and / or the transceiver 1222 of the device 1204 in the example are performed. In such examples, the value of the timing accuracy threshold is determined based on at least one of the following: a frequency range used for communicating with the active cell or the set of deactivated cells after the activation, a DL RS or a DL active or DL ​​SCS configured with a BWP for the active cell or the set of deactivated cells after the activation, a UL channel or a UL RS or a UL active or UL SCS configured with a BWP for communicating with the active cell or the set of deactivated cells after the activation, or a link quality associated with the active cell, the set of deactivated cells before the activation, or the set of deactivated cells after the activation.

[0116] At 1012, if the derived TA is not within the timing accuracy threshold, the UE may avoid applying the TA to the set of deactivated cells or to the initial Tx to the set of deactivated cells, such as in conjunction with Figures 7 to 9For example, if the derived TA 710 is not within the timing accuracy threshold, the UE 702 may avoid applying the TA 710 to the set of deactivated cells 708 or to the initial Tx to the set of deactivated cells 708. Avoiding applying the TA may be accomplished by, for example Fig.12 The TA derivation component 198, the cellular baseband processor 1224 and / or the transceiver 1222 of the device 1204 are executed.

[0117] At 1014, the UE may adjust the derived TA or UL Tx timing to meet the timing accuracy threshold, such as in conjunction with Figures 7 to 9 For example, UE 702 may adjust the derived TA 710 or UL Tx timing (gradually or all at once) to meet the timing accuracy threshold. The adjustment of the derived TA or UL Tx timing may be performed by, for example Fig.12 The TA derivation component 198, the cellular baseband processor 1224 and / or the transceiver 1222 of the device 1204 are executed.

[0118] In one example, the derived TA is gradually adjusted until the timing accuracy threshold is met. In such examples, the derived TA is gradually adjusted based on at least one of: a maximum amount of timing change in one adjustment, a minimum aggregate adjustment rate per second, or a maximum aggregate adjustment rate over a defined period.

[0119] In another example, the derived TA is adjusted once to meet the timing accuracy threshold. In such examples, the derived TA is adjusted based on at least one of the following: the capabilities of the UE, the frequency range used to communicate with the active cell or the set of deactivated cells after the activation, or a power class associated with the UE.

[0120] Fig.11 1100 is a flow chart of a method of wireless communication. The method may be performed by a UE (eg, UE 104, 402, 602, 702; device 1204). The method may enable the UE to maintain a TA on a set of deactivated candidate PCells to save or reduce new PCell activation delay.

[0121] At 1104, the UE may derive the TA of the set of deactivated cells based on the Rx time difference between the active cell and the set of deactivated cells, such as in combination with Figure 7 and 8 For example, at 714, UE 702 may derive TA 710 for the set of deactivated cells 708 based on the Rx time difference between active cell 706 and the set of deactivated cells 708. The derivation of the TA for the set of deactivated cells may be performed by, for example Fig.12The TA derivation component 198, the cellular baseband processor 1224 and / or the transceiver 1222 of the device 1204 are executed.

[0122] In an example, the set of deactivated cells corresponds to one deactivated cell or a deactivated TAG including a plurality of deactivated cells.

[0123] In another example, the UE may receive at least one of a Tx timing difference between the active cell and the set of deactivated cells or a UL-to-DL timing difference of each of the active cell and the set of deactivated cells from the network node, wherein the TA of the set of deactivated cells is further derived based on the Tx timing difference or the UL-to-DL timing difference.

[0124] In another example, the UE may receive a TA command from an active cell, wherein the TA command indicates a second TA of the active cell, and the UE may calculate the Rx time difference between the active cell and the set of deactivated cells based on the second TA, such as in combination with Figure 7 and 8 For example, at 712, UE 702 may receive a TA command including a TA of active cell 706 from active cell 706, and UE 702 may calculate an Rx time difference between active cell 706 and a set of deactivated cells 708 based on the TA of active cell 706. Receipt of a TA command and / or calculation of an Rx time difference may be performed by, for example Fig.12 1204, the TA derivation component 198, the cellular baseband processor 1224, and / or the transceiver 1222 of the device 1204 in the embodiment of the present invention are performed. In such examples, the TA of the set of deactivated cells is derived based on the following equation: T2=T1-2*(R1-R2)+[2*(S1-S2)-(Q1-Q2)], where T2 corresponds to the TA, T1 corresponds to the second TA, R1 corresponds to the first downlink (DL) Rx timing of the active cell, R2 corresponds to the second DL Rx timing of the set of deactivated cells, S1 corresponds to the first DL Tx timing of the active cell, S2 corresponds to the second DL Tx timing of the set of deactivated cells, Q1 corresponds to the first UL and DL timing difference of the active cell, and Q2 corresponds to the second UL and DL timing difference of the set of deactivated cells. In such examples, the first UL transmit timing (U1) of the active cell is determined based on the following equation: U1=R1-T1. In such examples, the second UL transmission timing (U2) of the set of deactivated cells is determined based on the following equation: U2=R2-T2; or U2=R2-T1+2*(R1-R2)-[2*(S1-S2)-(Q1-Q2)].

[0125] At 1106, the UE may maintain the TA of the set of deactivated cells prior to activation of the set of deactivated cells, such as in conjunction with Figure 7 and Figure 8 For example, UE 702 may maintain TA 710 for the set of deactivated cells 708 prior to activation of the set of deactivated cells 708. The maintenance of the TA may be performed by, for example Fig.12 The TA derivation component 198, the cellular baseband processor 1224 and / or the transceiver 1222 of the device 1204 are executed.

[0126] At 1108, the UE may apply the TA to the set of deactivated cells or to initial Tx to the set of deactivated cells in response to the activation of the set of deactivated cells, such as in conjunction with Figure 7 and Figure 8 For example, UE 702 may apply TA 710 to the set of deactivated cells 708 or to initial Tx to the set of deactivated cells 708 in response to the activation of the set of deactivated cells 708. Applying the TA to the set of deactivated cells or to initial Tx to the set of deactivated cells may be performed by, for example Fig.12 The TA derivation component 198, the cellular baseband processor 1224 and / or the transceiver 1222 of the device 1204 are executed.

[0127] In one example, the UE may determine whether the derived TA is within a timing accuracy threshold, wherein based on the derived TA satisfying the timing accuracy threshold, the TA is applied to the set of deactivated cells or to the initial Tx to the set of deactivated cells, such as in conjunction with Figures 7 to 9 For example, UE 702 may determine whether the derived TA 710 is within a timing accuracy threshold, and if TA 710 satisfies the timing accuracy threshold, UE 702 may apply TA 710 to the set of deactivated cells 708 or to the initial Tx to the set of deactivated cells 708. The determination of whether the derived TA is within the timing accuracy threshold may be performed by, for example Fig.12The TA derivation component 198, the cellular baseband processor 1224 and / or the transceiver 1222 of the device 1204 in the example are performed. In such examples, the value of the timing accuracy threshold is determined based on at least one of the following: a frequency range used for communicating with the active cell or the set of deactivated cells after the activation, a DL RS or a DL active or DL ​​SCS configured with a BWP for the active cell or the set of deactivated cells after the activation, a UL channel or a UL RS or a UL active or UL SCS configured with a BWP for communicating with the active cell or the set of deactivated cells after the activation, or a link quality associated with the active cell, the set of deactivated cells before the activation, or the set of deactivated cells after the activation.

[0128] In another example, if the derived TA is not within the timing accuracy threshold, the UE may avoid applying the TA to the set of deactivated cells or to the initial Tx to the set of deactivated cells, such as in conjunction with Figures 7 to 9 For example, if the derived TA 710 is not within the timing accuracy threshold, the UE 702 may avoid applying the TA 710 to the set of deactivated cells 708 or to the initial Tx to the set of deactivated cells 708. Avoiding applying the TA may be accomplished by, for example Fig.12 The TA derivation component 198, the cellular baseband processor 1224 and / or the transceiver 1222 of the device 1204 are executed.

[0129] In another example, the UE may adjust the derived TA or UL Tx timing to meet the timing accuracy threshold, such as in conjunction with Figures 7 to 9 For example, UE 702 may adjust the derived TA 710 or UL Tx timing (gradually or all at once) to meet the timing accuracy threshold. The adjustment of the derived TA or UL Tx timing may be performed by, for example Fig.12 The TA derivation component 198, the cellular baseband processor 1224 and / or the transceiver 1222 of the device 1204 in the embodiment of the present invention is performed. In one example, the derived TA is gradually adjusted until the timing accuracy threshold is met. In such examples, the derived TA is gradually adjusted based on at least one of the following: the maximum amount of timing change amplitude in one adjustment, the minimum aggregation adjustment rate per second, or the maximum aggregation adjustment rate for a defined time period. In another example, the derived TA is adjusted once to meet the timing accuracy threshold. In such examples, the derived TA is adjusted based on at least one of the following: the capabilities of the UE, the frequency range used to communicate with the active cell or the set of deactivated cells after the activation, or the power class associated with the UE.

[0130] Fig.121200 is an example of a hardware implementation of an example device 1204. The device 1204 may be a UE, a component of a UE, or may implement UE functionality. In some aspects, the device 1204 may include a cellular baseband processor 1224 (also referred to as a modem) coupled to one or more transceivers 1222 (e.g., a cellular RF transceiver). The cellular baseband processor 1224 may include on-chip memory 1224'. In some aspects, the device 1204 may also include one or more subscriber identity module (SIM) cards 1220 and an application processor 1206 coupled to a secure digital (SD) card 1208 and a screen 1210. The application processor 1206 may include on-chip memory 1206'. In some aspects, the device 1204 may also include a Bluetooth module 1212, a WLAN module 1214, an SPS module 1216 (e.g., a GNSS module), one or more sensor modules 1218 (e.g., an atmospheric pressure sensor / altimeter; a motion sensor such as an inertial measurement unit (IMU), a gyroscope, and / or an accelerometer; light detection and ranging (LIDAR), radio-aided detection and ranging (RADAR), sound navigation and ranging (SONAR), a magnetometer, audio, and / or other technologies for positioning), an additional memory module 1226, a power source 1230, and / or a camera 1232. The Bluetooth module 1212, the WLAN module 1214, and the SPS module 1216 may include an on-chip transceiver (TRX) (or in some cases, only a receiver (RX)). The Bluetooth module 1212, the WLAN module 1214, and the SPS module 1216 may include their own dedicated antennas and / or communicate using an antenna 1280. The cellular baseband processor 1224 communicates with the UE 104 and / or with the RU associated with the network entity 1202 through the transceiver 1222 via one or more antennas 1280. The cellular baseband processor 1224 and the application processor 1206 may each include a computer-readable medium / memory 1224', 1206', respectively. The additional memory module 1226 may also be considered a computer-readable medium / memory. Each computer-readable medium / memory 1224', 1206', 1226 may be non-transitory. The cellular baseband processor 1224 and the application processor 1206 are each responsible for general processing, including executing software stored on a computer-readable medium / memory. The software, when executed by the cellular baseband processor 1224 / application processor 1206, enables the cellular baseband processor 1224 / application processor 1206 to perform the various functions described above. The computer-readable medium / memory may also be used to store data manipulated by the cellular baseband processor 1224 / application processor 1206 when executing the software.The cellular baseband processor 1224 / application processor 1206 may be a component of the UE 350 and may include the memory 360 and / or at least one of the TX processor 368, the RX processor 356, and the controller / processor 359. In one configuration, the device 1204 may be a processor chip (modem and / or application) and include only the cellular baseband processor 1224 and / or the application processor 1206, while in another configuration, the device 1204 may be the entire UE (e.g., see. Figure 3 350) and includes additional modules of device 1204.

[0131] As discussed above, the TA derivation component 198 is configured to derive the TA of the set of deactivated cells based on the Rx time difference between the active cell and the set of deactivated cells. The TA derivation component 198 may also be configured to maintain the TA of the set of deactivated cells before the activation of the set of deactivated cells. The TA derivation component 198 may also be configured to apply the TA to the set of deactivated cells or to the initial Tx to the set of deactivated cells in response to the activation of the set of deactivated cells. The TA derivation component 198 may be in the cellular baseband processor 1224, the application processor 1206, or in both the cellular baseband processor 1224 and the application processor 1206. The TA derivation component 198 may be one or more hardware components, which are 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 so as to be implemented by one or more processors, or some combination thereof. As shown, the device 1204 may include a variety of components configured for various functions. In one configuration, the device 1204 (particularly the cellular baseband processor 1224 and / or the application processor 1206) includes: a component for deriving a TA of a set of deactivated cells based on an Rx time difference between an active cell and a set of deactivated cells. The device 1204 may also include: a component for maintaining the TA of the set of deactivated cells before activation of the set of deactivated cells. The device 1204 may also include: a component for applying the TA to the set of deactivated cells or to an initial Tx to the set of deactivated cells in response to the activation of the set of deactivated cells.

[0132] In one configuration, the set of deactivated cells corresponds to one deactivated cell or a deactivated TAG including a plurality of deactivated cells.

[0133] In another configuration, the device 1204 may also include: a component for receiving at least one of the Tx timing difference between the active cell and the set of deactivated cells or the UL-to-DL timing difference of each of the active cell and the set of deactivated cells from a network node, wherein the TA of the set of deactivated cells is further derived based on the Tx timing difference or the UL-to-DL timing difference.

[0134] In another configuration, the device 1204 may also include: a component for receiving a TA command from an active cell, wherein the TA command indicates a second TA of the active cell; and a component for calculating the Rx time difference between the active cell and the set of deactivated cells based on the second TA. In such a configuration, the TA of the set of deactivated cells is derived based on the following equation: T2=T1-2*(R1-R2)+[2*(S1-S2)-(Q1-Q2)], wherein T2 corresponds to the TA, T1 corresponds to the second TA, R1 corresponds to a first downlink (DL) Rx timing of the active cell, R2 corresponds to a second DL Rx timing of the set of deactivated cells, S1 corresponds to a first DL Tx timing of the active cell, S2 corresponds to a second DL Tx timing of the set of deactivated cells, Q1 corresponds to a first UL and DL timing difference of the active cell, and Q2 corresponds to a second UL and DL timing difference of the set of deactivated cells. In such a configuration, the first UL transmission timing (U1) of the active cell is determined based on the following equation: U1 = R1-T1. In such a configuration, the second UL transmission timing (U2) of the set of deactivated cells is determined based on the following equation: U2 = R2-T2; or U2 = R2-T1+2*(R1-R2)-[2*(S1-S2)-(Q1-Q2)].

[0135] In another configuration, the device 1204 may also include: a component for determining whether the derived TA is within a timing accuracy threshold, wherein based on the derived TA satisfying the timing accuracy threshold, the TA is applied to the set of deactivated cells or to the initial Tx to the set of deactivated cells. In such a configuration, the value of the timing accuracy threshold is determined based on at least one of the following: a frequency range used for communication with the active cell or the set of deactivated cells after the activation, a DL RS or a DL active or DL ​​SCS configured with a BWP for the active cell or the set of deactivated cells after the activation, a UL channel or a UL RS or a UL active or UL SCS configured with a BWP for communication with the active cell or the set of deactivated cells after the activation, or a link quality associated with the active cell, the set of deactivated cells before the activation, or the set of deactivated cells after the activation.

[0136] In another configuration, the apparatus 1204 may further include means for avoiding applying the TA to the set of deactivated cells or to the initial Tx to the set of deactivated cells if the derived TA is not within the timing accuracy threshold.

[0137] In another configuration, the apparatus 1204 may further include: a component for adjusting the derived TA or UL Tx timing to meet the timing accuracy threshold. In one configuration, the derived TA is gradually adjusted until the timing accuracy threshold is met. In such a configuration, the derived TA is gradually adjusted based on at least one of the following: the maximum amount of timing change amplitude in one adjustment, the minimum aggregate adjustment rate per second, or the maximum aggregate adjustment rate for a defined time period. In another configuration, the derived TA is adjusted once to meet the timing accuracy threshold. In such a configuration, the derived TA is adjusted based on at least one of the following: the capabilities of the UE, the frequency range used to communicate with the active cell or the set of deactivated cells after the activation, or the power class associated with the UE.

[0138] The means may be the TA derivation component 198 of the apparatus 1204 configured to perform the functions recited by the means. As described above, the apparatus 1204 may include the TX processor 368, the RX processor 356, and the controller / processor 359. Thus, in one configuration, the means may be the TX processor 368, the RX processor 356, and / or the controller / processor 359 configured to perform the functions recited by the means.

[0139] It should be understood that the specific order or hierarchy of the blocks in the disclosed process / flowchart is only an illustration of the exemplary method. It should be understood that the specific order or hierarchy of the blocks in the process / flowchart can be rearranged based on design preferences. In addition, some blocks can be combined or omitted. The attached method claims provide the elements of each block in a sample order, but are not limited to the specific order or hierarchy provided.

[0140] 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 various aspects described herein, but should be given the full scope consistent with the language claims. Unless otherwise specified, reference to an element in the singular form does not mean "one and only one", but "one or more". Terms such as "if", "when ..." and "at ..." do not mean a direct temporal relationship or reaction. That is, these phrases, such as "when ...", do not mean an instant action in response to the occurrence of an action or during the occurrence of an action, but only mean that if the condition is met, the action will occur without a specific or instantaneous time constraint to cause the action to occur. The word "exemplary" is used herein to mean "used as an example, instance, or illustration". Any aspect described as "exemplary" herein is not necessarily interpreted as being preferred or having an advantage over other aspects. Unless otherwise specified, 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, and 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" may 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 set of elements, where the number of elements is one or more. Thus, for a set of X, X will include one or more elements. If the first device receives data from the second device or sends data to the second device, data may be directly received / sent between the first device and the second device, or indirectly received / sent between the first device and the second device through a collection of devices. All structural and functional equivalents of the elements throughout the various aspects described in this disclosure that are known or will later be known to a person of ordinary skill in the art are expressly incorporated herein by reference and are covered by the claims. In addition, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly stated in the claims. Words such as "module", "mechanism", "element", "device", etc. cannot replace the word "component". Therefore, no claim element will be understood as a component plus function unless the element is explicitly stated using the phrase "component for..."

[0141] As used herein, 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, a condition, a factor, etc.) should be interpreted as "based at least on A" unless specifically stated differently.

[0142] The following aspects are merely illustrative and may be combined with other aspects or teachings described herein without limitation.

[0143] Aspect 1 is a method for performing wireless communication at a UE, the method comprising: deriving a TA of a set of deactivated cells based on an Rx time difference between an active cell and a set of deactivated cells; maintaining the TA of the set of deactivated cells before activation of the set of deactivated cells; and applying the TA to the set of deactivated cells or to an initial Tx to the set of deactivated cells in response to the activation of the set of deactivated cells.

[0144] Aspect 2 is a method according to aspect 1, wherein the set of deactivated cells corresponds to one deactivated cell or a deactivated TAG including a plurality of deactivated cells.

[0145] Aspect 3 is a method according to any one of Aspects 1 or 2, the method further comprising: receiving at least one of the Tx timing difference between the active cell and the set of deactivated cells or the uplink UL to DL timing difference of each of the active cell and the set of deactivated cells from a network node, wherein the TA of the set of deactivated cells is further derived based on the Tx timing difference or the UL to DL timing difference.

[0146] Aspect 4 is a method according to any one of Aspects 1 to 3, the method further comprising: receiving a TA command from the active cell, wherein the TA command indicates a second TA of the active cell; and calculating the Rx time difference between the active cell and the set of deactivated cells based on the second TA.

[0147] Aspect 5 is a method according to Aspect 4, wherein the TA of the set of deactivated cells is derived based on the following equation: T2=T1-2*(R1-R2)+[2*(S1-S2)-(Q1-Q2)], wherein T2 corresponds to the TA, T1 corresponds to the second TA, R1 corresponds to the first downlink (DL) Rx timing of the active cell, R2 corresponds to the second DL Rx timing of the set of deactivated cells, S1 corresponds to the first DL Tx timing of the active cell, S2 corresponds to the second DL Tx timing of the set of deactivated cells, Q1 corresponds to the first UL and DL timing difference of the active cell, and Q2 corresponds to the second UL and DL timing difference of the set of deactivated cells.

[0148] Aspect 6 is a method according to aspect 5, wherein the first UL transmission timing (U1) of the active cell is determined based on the following equation: U1=R1-T1.

[0149] Aspect 7 is a method according to Aspect 6, wherein the second UL transmission timing (U2) of the set of deactivated cells is determined based on the following equation: U2 = R2-T2; or U2 = R2-T1+2*(R1-R2)-[2*(S1-S2)-(Q1-Q2)].

[0150] Aspect 8 is a method according to any one of Aspects 1 to 7, the method further comprising: determining whether the derived TA is within a timing accuracy threshold, wherein based on the derived TA satisfying the timing accuracy threshold, the TA is applied to the set of deactivated cells or to the initial Tx to the set of deactivated cells.

[0151] Aspect 9 is a method according to Aspect 8, wherein the value of the timing accuracy threshold is determined based on at least one of the following: a frequency range used for communicating with the active cell or the set of deactivated cells after the activation, a DL RS or DL ​​active or DL ​​SCS configured with BWP for the active cell or the set of deactivated cells after the activation, a UL channel or UL RS or UL active or UL SCS configured with BWP for communicating with the active cell or the set of deactivated cells after the activation, or a link quality associated with the active cell, the set of deactivated cells before the activation, or the set of deactivated cells after the activation.

[0152] Aspect 10 is a method according to aspect 8, the method further comprising: when the derived TA is not within the timing accuracy threshold, avoiding applying the TA to the set of deactivated cells or to the initial Tx to the set of deactivated cells.

[0153] Aspect 11 is a method according to aspect 10, the method further comprising: adjusting the derived TA or UL Tx timing to meet the timing accuracy threshold.

[0154] Aspect 12 is a method according to aspect 11, wherein the derived TA is gradually adjusted until the timing accuracy threshold is met.

[0155] Aspect 13 is a method according to aspect 12, wherein the derived TA is gradually adjusted based on at least one of the following: a maximum amount of timing change amplitude in one adjustment, a minimum aggregate adjustment rate per second, or a maximum aggregate adjustment rate for a defined period.

[0156] Aspect 14 is a method according to aspect 11, wherein the derived TA is adjusted once to meet the timing accuracy threshold.

[0157] Aspect 15 is a method according to aspect 14, wherein the derived TA is adjusted based on at least one of the following: the capability of the UE, the frequency range used for communicating with the active cell or the set of deactivated cells after the activation, or a power class associated with the UE.

[0158] Aspect 16 is an apparatus for performing wireless communications at a UE, the apparatus comprising: a memory; and at least one processor, the at least one processor being coupled to the memory and being configured to implement any one of Aspects 1 to 15 based at least in part on information stored in the memory.

[0159] Aspect 17 is the apparatus of aspect 16, the apparatus further comprising at least one of a transceiver or an antenna coupled to the at least one processor.

[0160] Aspect 18 is an apparatus for wireless communication, the apparatus comprising means for implementing any one of aspects 1 to 15.

[0161] Aspect 19 is a computer-readable medium (eg, 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 15.

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 based at least in part on the information stored in the memory, the at least one processor configured to: deriving a timing advance (TA) of the set of deactivated cells based on a receive (Rx) time difference between the active cell and the set of deactivated cells; maintaining the TA of the set of deactivated cells before activation of the set of deactivated cells; as well as The TA is applied to the set of deactivated cells or to an initial transmission (Tx) to the set of deactivated cells in response to the activation of the set of deactivated cells. 2 . The apparatus according to claim 1 , wherein the set of deactivated cells corresponds to one deactivated cell or a deactivated timing advance group (TAG) including a plurality of deactivated cells.

3. The apparatus of claim 1 , wherein the at least one processor is further configured to: Receiving at least one of a Tx timing difference between the active cell and the set of deactivated cells or an uplink (UL) to (DL) timing difference of each of the active cell and the set of deactivated cells from a network node, wherein the TA of the set of deactivated cells is further derived based on the Tx timing difference or the UL to DL timing difference.

4. The apparatus of claim 1 , wherein the at least one processor is further configured to: receiving a TA command from the active cell, wherein the TA command indicates a second TA of the active cell; and The Rx time difference between the active cell and the set of deactivated cells is calculated based on the second TA.

5. The apparatus of claim 4, wherein the TA of the set of deactivated cells is derived based on the following equation: T2=T1-2*(R1-R2)+[2*(S1-S2)-(Q1-Q2)], wherein T2 corresponds to the TA, T1 corresponds to the second TA, R1 corresponds to a first downlink (DL) Rx timing of the active cell, R2 corresponds to a second DL Rx timing of the set of deactivated cells, S1 corresponds to a first DL Tx timing of the active cell, S2 corresponds to a second DL Tx timing of the set of deactivated cells, Q1 corresponds to a first UL and DL timing difference of the active cell, and Q2 corresponds to a second UL and DL timing difference of the set of deactivated cells.

6. The apparatus according to claim 5, wherein the first UL transmission timing (U1) of the active cell is determined based on the following equation: U1 = R1 - T1.

7. The apparatus according to claim 6, wherein the second UL transmission timing (U2) of the set of deactivated cells is determined based on the following equation: U2 = R2 - T2; or U2 = R2 - T1 + 2*(R1 - R2) - [2*(S1 - S2) - (Q1 - Q2)].

8. The apparatus of claim 1, wherein the at least one processor is further configured to: Determining whether the derived TA is within a timing accuracy threshold, wherein based on the derived TA satisfying the timing accuracy threshold, applying the TA to the set of deactivated cells or to the initial Tx to the set of deactivated cells.

9. The apparatus of claim 8, wherein the value of the timing accuracy threshold is determined based on at least one of the following: a frequency range used for communicating with the active cell or the set of deactivated cells after the activation, a downlink (DL) subcarrier spacing (SCS) of a DL reference signal (RS) or a DL active or configured bandwidth part (BWP) for the active cell or the set of deactivated cells after the activation, A UL channel or UL RS or an uplink (UL) SCS of a UL active or configured BWP for communicating with the active cell or the set of deactivated cells after the activation, or A link quality associated with the active cell, the set of deactivated cells before the activation, or the set of deactivated cells after the activation.

10. The apparatus of claim 8, wherein the at least one processor is further configured to: In case the derived TA is not within the timing accuracy threshold, applying the TA to the set of deactivated cells or to the initial Tx to the set of deactivated cells is avoided.

11. The apparatus of claim 10, wherein the at least one processor is further configured to: The derived TA or uplink (UL) Tx timing is adjusted to meet the timing accuracy threshold.

12. The apparatus of claim 11, wherein the derived TA is gradually adjusted until the timing accuracy threshold is met.

13. The apparatus of claim 12, wherein the derived TA is gradually adjusted based on at least one of: The maximum amount of timing change in one adjustment. The minimum aggregate adjustment rate per second, or Defines the maximum aggregate adjustment rate for the period. The apparatus of claim 11 , wherein the derived TA is adjusted once to meet the timing accuracy threshold.

15. The apparatus of claim 14, wherein the derived TA is adjusted based on at least one of: The capabilities of the UE, a frequency range used for communicating with the active cell or the set of deactivated cells after the activation, or a power class associated with the UE.

16. A method of wireless communication at a user equipment (UE), the method comprising: deriving a timing advance (TA) of the set of deactivated cells based on a receive (Rx) time difference between the active cell and the set of deactivated cells; maintaining the TA of the set of deactivated cells before activation of the set of deactivated cells; as well as The TA is applied to the set of deactivated cells or to an initial transmission (Tx) to the set of deactivated cells in response to the activation of the set of deactivated cells. 17 . The method according to claim 16 , wherein the set of deactivated cells corresponds to one deactivated cell or a deactivated timing advance group (TAG) including a plurality of deactivated cells.

18. The method according to claim 16, further comprising: Receiving at least one of a Tx timing difference between the active cell and the set of deactivated cells or an uplink (UL) to (DL) timing difference of each of the active cell and the set of deactivated cells from a network node, wherein the TA of the set of deactivated cells is further derived based on the Tx timing difference or the UL to DL timing difference.

19. The method according to claim 16, further comprising: receiving a TA command from the active cell, wherein the TA command indicates a second TA of the active cell; as well as The Rx time difference between the active cell and the set of deactivated cells is calculated based on the second TA.

20. The method of claim 19, wherein the TA of the set of deactivated cells is derived based on the following equation: T2 = T1-2*(R1-R2)+[2*(S1-S2)-(Q1-Q2)], wherein T2 corresponds to the TA, T1 corresponds to the second TA, R1 corresponds to a first downlink (DL) Rx timing of the active cell, R2 corresponds to a second DL Rx timing of the set of deactivated cells, S1 corresponds to a first DL Tx timing of the active cell, S2 corresponds to a second DL Tx timing of the set of deactivated cells, Q1 corresponds to a first UL and DL timing difference of the active cell, and Q2 corresponds to a second UL and DL timing difference of the set of deactivated cells.

21. The method according to claim 20, wherein the first UL transmission timing (U1) of the active cell is determined based on the following equation: U1=R1-T1; and the second UL transmission timing (U2) of the set of deactivated cells is determined based on the following equation: U2=R2-T2; or U2=R2-T1+2*(R1-R2)-[2*(S1-S2)-(Q1-Q2)].

22. The method according to claim 16, further comprising: Determining whether the derived TA is within a timing accuracy threshold, wherein based on the derived TA satisfying the timing accuracy threshold, applying the TA to the set of deactivated cells or to the initial Tx to the set of deactivated cells.

23. The method of claim 22, wherein the value of the timing accuracy threshold is determined based on at least one of: a frequency range used for communicating with the active cell or the set of deactivated cells after the activation, a downlink (DL) subcarrier spacing (SCS) of a DL reference signal (RS) or a DL active or configured bandwidth part (BWP) for the active cell or the set of deactivated cells after the activation, A UL channel or UL RS or an uplink (UL) SCS of a UL active or configured BWP for communicating with the active cell or the set of deactivated cells after the activation, or A link quality associated with the active cell, the set of deactivated cells before the activation, or the set of deactivated cells after the activation.

24. The method according to claim 22, further comprising: In case the derived TA is not within the timing accuracy threshold, applying the TA to the set of deactivated cells or to the initial Tx to the set of deactivated cells is avoided.

25. The method according to claim 24, further comprising: The derived TA or uplink (UL) Tx timing is adjusted to meet the timing accuracy threshold.

26. The method of claim 25, wherein the derived TA is adjusted gradually until the timing accuracy threshold is met, or the derived TA is adjusted once to meet the timing accuracy threshold.

27. The method of claim 26, wherein the derived TA is gradually adjusted based on at least one of: The maximum amount of timing change in one adjustment. The minimum aggregate adjustment rate per second, or Defines the maximum aggregate adjustment rate for the period.

28. The method of claim 26, wherein the derived TA is adjusted based on at least one of: The capabilities of the UE, a frequency range used for communicating with the active cell or the set of deactivated cells after the activation, or a power class associated with the UE.

29. An apparatus for wireless communication at a user equipment (UE), the apparatus comprising: means for deriving a timing advance (TA) of the set of deactivated cells based on a receive (Rx) time difference between the active cell and the set of deactivated cells; means for maintaining the TA of the set of deactivated cells prior to activation of the set of deactivated cells; and Means for applying the TA to the set of deactivated cells or to an initial transmission (Tx) to the set of deactivated cells in response to the activation of the set of deactivated cells.

30. A computer readable medium storing computer executable code at a user equipment (UE) which, when executed by a processor, causes the processor to: deriving a timing advance (TA) of the set of deactivated cells based on a receive (Rx) time difference between the active cell and the set of deactivated cells; maintaining the TA of the set of deactivated cells prior to activation of the set of deactivated cells; and The TA is applied to the set of deactivated cells or to an initial transmission (Tx) to the set of deactivated cells in response to the activation of the set of deactivated cells.

Images