Conditional handover including target MCG and target SCG

Abstract

The UE receives a conditional handover configuration for handover to one of a plurality of candidate target PCells, the conditional handover configuration including a plurality of candidate target PSCells associated with each of the candidate target PCells in the conditional handover configuration; in response to a conditional handover execution condition being satisfied, performing a conditional handover from the source PCell to a target PCell from the plurality of candidate target PCells; selecting, on the basis of a PSCell selection execution condition, a PSCell from among the plurality of candidate target PSCell configured in the conditional handover configuration for the target PCell; and performing communication with a network on the target PCell and the selected PSCell.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of and priority to U.S. Provisional Application Serial No. 63 / 377,949, filed on September 30, 2022, entitled “CONDITIONAL HANDOVER INCLUDINGTARGET MCG AND TARGET SCGS,” and U.S. Non-Provisional Patent Application Serial No. 18 / 477,301, filed on September 28, 2023, entitled “CONDITIONAL HANDOVER INCLUDING TARGET MCG AND TARGET SCGS,” the entire texts of which are expressly incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to communication systems, and more particularly to wireless communications including handovers between network nodes. Background Art

[0004] 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.

[0005] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at a city, country, region, and even global level. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of the continuous mobile broadband evolution promulgated by the 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. 5GNR includes services associated with enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable low latency communication (URLLC). Certain aspects of 5G NR may be based on 4G Long Term Evolution (LTE) standards. It is necessary to further improve 5G NR technology. In addition, these improvements may also be applicable to other multiple access technologies and telecommunication standards that employ these technologies. Summary of the invention

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

[0007] In one aspect of the present disclosure, a method, a computer-readable medium, and an apparatus for wireless communication at a user equipment (UE) are provided. The apparatus receives a conditional handover configuration for handing over to one of a plurality of candidate target primary cells (PCells), the conditional handover configuration comprising a plurality of candidate target primary and secondary cells (PSCells) associated with each candidate target PCell in the conditional handover configuration. In response to the conditional handover execution condition being met, the apparatus performs a conditional handover from a source PCell to a target PCell from a plurality of candidate target PCells, and selects a PSCell from a plurality of candidate target PSCells configured in the conditional handover configuration for the target PCell based on the PSCell selection execution condition. The apparatus communicates with a network on the target PCell and the selected PSCell.

[0008] In one aspect of the present disclosure, a method, a computer-readable medium, and an apparatus for communicating at a source master node (MN) are provided. The apparatus provides a request for conditional handover including UE measurement information to at least one target MN, and receives a response indicating multiple candidate target PSCells associated with the candidate target PCell from each of the at least one target MN. The apparatus configures a conditional handover configuration for the UE to hand over to one of the multiple candidate target PCells, and includes multiple candidate target PSCells associated with each candidate target PCell in the configuration.

[0009] In one aspect of the present disclosure, a method, computer readable medium, and apparatus for communicating at a target MN are provided. The apparatus receives a request associated with a conditional handover from a source MN, the request identifying a candidate target PCell and including UE measurement information; and indicates to the source MN a plurality of candidate target PSCells associated with the candidate target PCell for the conditional handover.

[0010] In one aspect of the present disclosure, a method, computer readable medium, and apparatus for communicating at a target secondary node (SN) are provided. The apparatus receives an attach request associated with a conditional handover for a user equipment from a target MN; and sends a response to the target MN indicating a plurality of candidate target PSCells associated with the conditional handover to the target MN.

[0011] 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 indicate only some of the various ways in which the principles of the various aspects can be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network.

[0013] Figure 2A is a diagram illustrating an example of a first frame according to various aspects of the present disclosure.

[0014] Figure 2B is a diagram illustrating an example of downlink (DL) channels within a subframe according to various aspects of the present disclosure.

[0015] Figure 2C is a diagram illustrating an example of a second frame according to various aspects of the present disclosure.

[0016] Figure 2D is a diagram illustrating an example of uplink (UL) channels within a subframe according to various aspects of the present disclosure.

[0017] Figure 3 is a diagram illustrating an example of a base station and a user equipment (UE) in an access network.

[0018] Figure 4 A communication flow diagram illustrating a conditional handover according to various aspects of the present disclosure.

[0019] Figure 5 is a flow chart of a method of wireless communication at a UE according to various aspects of the present disclosure.

[0020] Figure 6 is a flow chart of a method of wireless communication at a source MN according to various aspects of the present disclosure.

[0021] Fig. 7A and Figure 7B is a flow chart of a method of wireless communication at a target MN according to various aspects of the present disclosure.

[0022] Figure 8 is a flow chart of a method of performing wireless communication at a target SN according to various aspects of the present disclosure.

[0023] Fig. 9 is a diagram illustrating an example of a hardware implementation for an example apparatus and / or UE.

[0024] Fig.10 is a diagram illustrating an example of a hardware implementation for an example network entity. DETAILED DESCRIPTION

[0025] Aspects presented in the present application help to extend support for conditional handover (CHO) using a multi-radio dual connection (MR-DC) configuration, in which multiple candidate SCGs can be configured. The radio link quality of the target PSCell in a CHO with an MR-DC configuration may be poor when the CHO is performed. If multiple candidate PSCells are configured, the UE is more likely to be able to access a candidate PSCell with good radio link quality when the CHO is performed. Therefore, the aspects presented in the present application help to improve mobility for the UE. By increasing the likelihood that the UE will be able to access a candidate PSCell with good radio link quality when performing CHO, the various aspects presented herein help to provide continuity of service and improve communication between the UE and the network.

[0026] The specific embodiments described below in conjunction with the accompanying drawings are descriptions of various configurations and do not represent the only configurations in which the concepts described herein can be practiced. 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 cases, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

[0027] Several aspects of telecommunication systems are 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 such elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0028] 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. When multiple processors are implemented, the multiple processors can perform functions individually or in combination. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on chip (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gating logic, 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, procedures, functions, or any combination thereof.

[0029] Thus, in one or more example aspects, specific implementations and / or use cases, the described functionality may be implemented in hardware, software, or any combination thereof. If implemented in software, the functionality may be stored or encoded as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media. Storage media may be any available media 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 media that can be used to store computer-executable code in the form of instructions or data structures that can be accessed by a computer.

[0030] 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 / or 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, various 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, devices that enable artificial intelligence (AI), etc.). Although some examples may or may not be specifically for use cases or applications, the described examples may have a wide range of applicability. Various 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 actual settings, the equipment combined with the various aspects and features described may also include additional components and features for implementing and practicing the claimed and described aspects. For example, the transmission and reception of wireless signals necessarily include multiple components for analog and digital purposes (e.g., hardware components including antennas, RF chains, power amplifiers, modulators, buffers, processors, interleavers, adders / summers, etc.) The various 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.

[0031] 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 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 or 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.

[0032] 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).

[0033] 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. Various units of a disaggregated base station or disaggregated RAN architecture may be configured for wired or wireless communication with at least one other unit.

[0034] 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.

[0035] 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 referred to as signals) via a wired or wireless transmission medium. Each of the 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 that is configured to receive signals or send signals to one or more of the other units via 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 and / or send signals to one or more of the other units via a wireless transmission medium.

[0036] 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 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.

[0037] 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.) at least in part according to a functional split such as those 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.

[0038] 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 specific 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).

[0039] 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. In addition, 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 .

[0040] 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 communicate 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 the O-eNB with the near-RT RIC 125.

[0041] 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 creation of RAN management policies (such as A1 policies).

[0042] 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 with a bandwidth of up to Y MHz (e.g., 5MHz, 10MHz, 15MHz, 20MHz, 100MHz, 400MHz, etc.). These carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL ​​compared to UL). Component carriers may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell) and the secondary component carrier may be referred to as a secondary cell (SCell).

[0043] 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). D2D communication may be performed via various wireless D2D communication systems, such as, for example, TM (Bluetooth is a trademark of the Bluetooth Special Interest Group (SIG)), Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard TM (Wi-Fi is a trademark of the Wi-Fi Alliance), LTE or NR.

[0044] 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.

[0045] 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 referred to (interchangeably) 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 it is different from the extremely high frequency (EHF) band (30 GHz–300 GHz) that is identified as the "millimeter wave" band by the International Telecommunication Union (ITU).

[0046] 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, and thus 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.

[0047] In view of the above, unless otherwise specified, if the term "6 GHz or less" is used herein, it may 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 herein, it may 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.

[0048] 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 may not be the same. The transmit direction and receive direction of the UE 104 may be the same or may not be the same.

[0049] 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 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 and 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 decomposed base station including one or more of a CU, a DU, and / or a RU. A set of base stations that may include decomposed base stations and / or aggregated base stations may be referred to as a next generation (NG) RAN (NG-RAN).

[0050] 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 the core network 120. AMF 161 supports registration management, connection management, mobility management, and other functions. SMF 162 supports session management and other functions. UPF 163 supports packet routing, packet forwarding, and other functions. UDM 164 supports 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, LMF 166, position determination entity (PDE), service mobile location center (SMLC), mobile positioning center (MPC), etc. GMLC 165 and LMF 166 support UE location services. GMLC 165 provides an interface for clients / applications (e.g., emergency services) to access UE positioning information. LMF 166 receives measurement and assistance information from NG-RAN and UE 104 via AMF 161 to calculate the location of UE 104. NG-RAN may determine the location of UE 104 using one or more positioning methods. Positioning UE 104 may involve signal measurements, position estimation, and optional speed calculation based on these measurements. Signal measurements may be performed by UE 104 and / or base station 102 serving UE 104. 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 / positioning 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.

[0051] 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.

[0052] Refer again Figure 1 In certain aspects, the UE 104 may include a CHO component 198 configured to receive a conditional handover configuration for handover to one of a plurality of candidate target PCells, the conditional handover configuration including a plurality of candidate target PSCells associated with each candidate target PCell in the conditional handover configuration; in response to satisfying a conditional handover execution condition, perform a conditional handover from a source PCell to a target PCell from the plurality of candidate target PCells; and based on the PSCell selection execution condition, select a PSCell from the plurality of candidate target PSCells configured in the conditional handover configuration for the target PCell. The UE 104 may also be configured to communicate with the network on the target PCell and the selected PSCell after performing the handover and the PSCell change.

[0053] In certain aspects, the base station 102 may include a CHO component 199. In some aspects, such as when the base station 102 is a source MN, the CHO component 199 may be configured to provide a request for conditional handover including UE measurement information to at least one target MN; receive a response indicating multiple candidate target PSCells associated with the candidate target PCell from each of the at least one target MN; and configure a conditional handover configuration for the UE to hand over to one of the multiple candidate target PCells, and include multiple candidate target PSCells associated with each candidate target PCell in the configuration. In some aspects, such as when the base station 102 is a target MN, the CHO component 199 may be configured to receive a request associated with conditional handover from a source MN, the request identifying the candidate target PCell and including UE measurement information; and indicate to the source MN multiple candidate target PSCells associated with the candidate target PCell for conditional handover. In some aspects, such as when base station 102 is a target SN, CHO component 199 may be configured to receive an additional request associated with a conditional handover for a user equipment from a target MN; and send a response to the target MN indicating a plurality of candidate target PSCells associated with the conditional handover. (199). Although the following description may focus on 5G NR, the concepts described herein may be applicable to other similar fields, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0054] 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 0-61. Slot formats 0 and 1 are full DL and full UL, respectively. Other slot formats 2-61 include a mix of DL, UL and flexible symbols. The UE is configured with the slot format through the received slot format indicator (SFI) (dynamically configured through DL control information (DCI) or semi-statically / statically configured through radio resource control (RRC) signaling). Note that the following description also applies to the 5G NR frame structure as TDD.

[0055] 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 equally sized subframes (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 normal or extended. For a normal 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) extended OFDM (DFT-s-OFDM) symbol (for power-constrained scenarios; limited to single-stream transmission). The number of time slots within a subframe is based on the CP and parameter set. The numerology defines the subcarrier spacing (SCS) (see Table 1). The symbol length / duration can be scaled with 1 / SCS.

[0056]

[0057] Table 1: Parameter set, SCS and CP

[0058] 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. Thus, 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 is provided for a normal CP with 14 symbols per slot and a parameter set μ=2 with 4 slots per subframe. 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).

[0059] 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.

[0060] 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 one 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).

[0061] 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 not sent over the PBCH (such as the system information block (SIB)), and paging messages.

[0062] 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, the PUCCH DM-RS may be sent in different configurations. 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 comb structures in the comb structure. The SRS may be used by the base station for channel quality estimation to achieve frequency-dependent scheduling of the UL.

[0063] 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.

[0064] Figure 3 375. The Controller / Processor 375 is a block diagram of a base station 310 in an access network communicating with a UE 350. 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 transfer 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.

[0065] 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 coded and modulated symbols may then be separated into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially pre-coded 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 for transmission using a corresponding spatial stream.

[0066] 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 stream destined for the UE 350. If multiple spatial streams are destined for the UE 350, they can be combined 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 base station 310. The data and control signals are then provided to controller / processor 359, which implements layer 3 and layer 2 functionality.

[0067] The controller / processor 359 may be associated with at least one memory 360 that stores program codes and data. The at least one memory 360 may be referred to as a computer-readable medium. In the UL, the controller / processor 359 provides demultiplexing between 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.

[0068] Similar to the functionality 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.

[0069] Channel estimates derived by the channel estimator 358 based on a reference signal or feedback sent by the base station 310 may be used by the TX processor 368 to select the 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 separate transmitters 354Tx. Each transmitter 354Tx may modulate an RF carrier with a corresponding spatial stream for transmission.

[0070] 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 respective antenna 320. Each receiver 318Rx recovers information modulated onto an RF carrier and provides the information to the RX processor 370.

[0071] The controller / processor 375 may be associated with at least one memory 360 that stores program codes and data. The at least one memory 376 may be referred to as a computer-readable medium. In the UL, the controller / processor 375 provides demultiplexing between 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.

[0072] 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 CHO component 198 combines various aspects.

[0073] At least one of the TX processor 316, the RX processor 370, and the controller / processor 375 may be configured to perform operations related to Figure 1 The CHO component 199 combines various aspects.

[0074] Aspects presented herein help extend support for conditional handover CHO with a multi-radio dual connectivity (MR-DC) configuration in which multiple candidate SCGs may be configured. The radio link quality of a target PSCell in a CHO with an MR-DC configuration may be poor when the CHO is performed. If multiple candidate PSCells are configured, the UE is more likely to be able to access a candidate PSCell with good radio link quality when the CHO is performed.

[0075] Figure 4 An example signaling flow 400 between various entities for a CHO procedure is illustrated. As shown at 410, a UE 402 provides a measurement report to a source MN 404 (e.g., a current serving MN). The MN may be referred to herein as a master node. In some aspects, the MN may be referred to as a master node. The MN may be associated with a primary cell group (e.g., which may be referred to as a primary cell group (MCG)). The MCG may include a PCell. The SN may be associated with a secondary cell group (SCG) and may include a PSCell. The UE may be configured to communicate with a MN 404 and a SN 405 (e.g., a source SN).

[0076] At 412, the source MN 404 initiates a CHO procedure and sends a handover request to the target MN 406. The handover request message may include the source SN UE XnAP ID (e.g., which is used as a reference to the UE context in the SN), the target PCell ID, a CHO indicator (e.g., indicating that the CHO procedure has been initiated), UE measurement results (e.g., based on the measurements reported at 410), and / or any of the source MCG and SCG configurations. The source MN 404 may determine an execution condition for the CHO configuration (e.g., which may be referred to as a conditional handover execution condition). Although Figure 4 Only a request transmitted to a single target MN 406 is illustrated, but the source MN 404 may transmit such a request to multiple target MNs.

[0077] Upon receiving the handover request (e.g., 412), the target MN 406 may decide to release the SN (e.g., SN 405), change the SN (e.g., change to an SN different from 405), or keep the SN (e.g., SN 405). If the target MN 406 decides to change the SN or keep the SN, and further decides to request a set of target SNs to prepare multiple candidate PSCells, the target MN sends an SN add request to each of the one or more target SNs. Figure 4 An example request 414 to a single target SN 408 is illustrated to illustrate the concept. Similar requests (eg, 414) may be transmitted to multiple target SNs.

[0078] The target MN 406 may determine a list of candidate PSCells to be proposed to the target SN using the UE measurement result information provided by the source MN 404 in the handover request 412. The source MN 404 may indicate to the target MN 406 the maximum number of candidate target PSCells that the target MN may propose to be configured to the target SN.

[0079] Based on the UE measurement results received from the source MN 404, the target MN 406 may transmit an SN add request 414 to one or more target SNs 408. The SN add request may include any combination of: a set of recommendations for PSCells to be considered for configuration by the target SN, UE measurement results (e.g., as received by the target MN from the source MN), a conditional PSCell change (CPC) indicator (e.g., indicating that the request is a conditional evaluation of the PSCell), a CHO indicator (e.g., indicating to the target SN that a procedure for configuring multiple candidate PSCells is part of a CHO procedure), a source SN UE XnAP ID, and / or a source SCG configuration.

[0080] In response to the add request 414, the target SN 408 may prepare a set of PSCells for confirmation to the target MN 406. As an example, the target SN may prepare a subset of the proposed PSCells indicated by the target MN 406 and may respond with an SN add request confirmation message 416 (e.g., which may also be referred to as an SN add response message).

[0081] The target SN prepares a subset of the proposed set of PSCells indicated by the target MN and responds with an SN Add Request Confirmation message, which may include any combination of the set of prepared (candidate target) PSCells (which may be a subset of the proposed set indicated in the SN Add Request 414), the target SCG configuration associated with each candidate target PSCell, and / or the data forwarding addresses of the bearers to be moved to the SN (e.g., 408).

[0082] The target MN 406 sends a handover request confirmation message 418, which includes the candidate target PCell and the candidate target PSCell provided by the target SN (e.g., one or more target SNs 408) with which the target MN 406 initiated the SN addition procedure (e.g., through request 414). The handover request confirmation message 418 may include the data forwarding addresses of the bearers to be moved to the target MN and the target SN as a result of the conditional handover.

[0083] In some aspects, upon receiving the handover request confirmation message 418, the source MN 404 may immediately send an Xn-U address indication message 420 notifying the CHO to the source SN 405. The source MN 404 may provide a data forwarding address including its own address and the address received by the source MN 404 in the handover request confirmation message 418 in the Xn-U address indication message 420. The source SN 405 may initiate early data forwarding upon receiving the Xn-U address indication. In some aspects, a separate Xn-U address indication procedure may be invoked to provide a different forwarding address for a prepared conditional handover.

[0084] Although the example is illustrated for a single Pcell for explaining the concept, multiple candidate target PCells may be prepared in the CHO procedure initiated by the source MN 404, and each of the candidate target PCells may have an associated set of prepared candidate target PSCells.

[0085] Upon receiving the handover request confirmation message 418 from the target MN 406, the source MN 404 knows that, for example, information about the candidate target PCell and candidate target PSCell prepared by the target MN 406 and the target SN 408 has been received from the target MN, for example, as shown at 412, 414, 416, 418 and 420.

[0086] The source MN 404 may determine at 422 an execution condition (e.g., which may be referred to as a PSCell selection execution condition, a PSCell change execution condition, CPC, etc.) for accessing multiple candidate target PSCells prepared in the procedure (e.g., as shown at 412, 414, 416, 418, and 420).

[0087] The source MN 404 sends an RRC reconfiguration message 424 (e.g., which may be referred to as an "RRCReconfiguration" message) including any combination of candidate target PCells for CHO; execution conditions for the candidate target PCells (e.g., conditional handover execution conditions); for each candidate target PCell, a set of candidate target PSCells considered for conditional evaluation; and execution conditions associated with the candidate target PSCells (e.g., PSCell selection execution conditions), and / or target MCG and SCG configurations associated with the candidate target PCell and the candidate target PSCell. In some aspects, the execution conditions may be referred to as PSCell selection execution conditions.

[0088] The RRC reconfiguration message 424 may include measurement configuration performed by the source MN 404, including configuration of measurement candidate target PCell and / or candidate target PSCell for the UE. The corresponding execution condition may be indicated using measurement identification information (such as measID) associated with the measurement configuration provided by the source MN.

[0089] UE 402 may send a reply to RRC reconfiguration message 424 (eg, RRC reconfiguration complete message 426) to source MN 404 to confirm the provided configuration.

[0090] As shown at 428, the UE may evaluate conditional configuration conditions (e.g., conditional handover execution conditions for CHO to a new PCell and / or PSCell selection execution conditions (which may also be referred to as PSCell change execution conditions or CPCs) to select a PSCell associated with the PCell in conjunction with the CHO). There are various options for UE processing of conditional configuration evaluations (e.g., as shown at 428 and 430). In some aspects, the UE 402 may simultaneously initiate conditional evaluations of CHO (e.g., evaluating whether the CHO execution conditions are satisfied) and CPC (e.g., evaluating whether the PSCell selection execution conditions are satisfied). In other aspects, the UE may initiate a conditional evaluation of CHO (e.g., evaluating whether the CHO execution conditions are satisfied) before initiating an evaluation of CPC (e.g., evaluating whether the PSCell selection execution conditions are satisfied).

[0091] If the CHO evaluation is triggered simultaneously with CPC for a candidate target PCell and an associated candidate target PSCell, the UE 402 may access these cells (eg, the PCell and the associated PSCell) simultaneously.

[0092] If CHO is triggered before CPC (e.g., evaluation of PSCell selection execution condition), UE 402 may access the candidate target PCell before the candidate target PSCell and may continue to evaluate CPC corresponding to the cell (e.g., target PCell). Then, when CPC is triggered later (e.g., PSCell selection execution condition is met), UE 402 may access the candidate target PSCell.

[0093] If the UE is performing simultaneous evaluations, and CPC evaluation (e.g., PSCell selection execution conditions are satisfied) is triggered before CHO is triggered (e.g., conditional handover execution conditions are satisfied), the UE 402 may not access the candidate target PSCell because the UE 402 first performs a PCell change. In this case, the UE may continue CPC evaluation (e.g., evaluation of execution conditions for the candidate target PSCell) and CHO evaluation (e.g., evaluation of execution conditions for CHO to the candidate target PCell). The UE waits for CHO of the PCell to be triggered before making a change based on CPC (e.g., PSCell evaluation).

[0094] If the UE 402 initiates CPC evaluation after initiating CHO evaluation (e.g., for a PSCell), in some aspects, the UE may initiate CPC evaluation after a portion of a time to trigger (TTT) for CHO evaluation has completed. The TTT corresponds to a continuous time period during which an execution condition will be satisfied, after which CHO is triggered. The portion of the TTT during which the UE initiates CPC evaluation may be network configured.

[0095] Figure 4 As illustrated at 430, the execution conditions for the candidate target PCell and the candidate target PSCell are met, and at 432, the UE 402 performs a RACH procedure with the target MN 406 and the target SN 408, after which the UE can provide an RRC reconfiguration complete message 434 to the target MN 406, and the target MN 406 can provide an indication to the target SN 408.

[0096] Figure 5 5 is a flow chart of a wireless communication method. The method may be performed by a UE (e.g., UE 104, 350, 402; device 904). The method may help improve the mobility of the UE by configuring multiple candidate PSCells for the UE, which increases the likelihood that the UE will be able to access a candidate PSCell with good radio link quality when performing CHO. Therefore, the method may help provide continuity of service and improve communication between the UE and the network.

[0097] At 502, the UE receives a conditional handover configuration for handover to one of a plurality of candidate target PCells, the conditional handover configuration comprising a plurality of candidate target PSCells associated with each candidate target PCell in the conditional handover configuration. Figure 4 Various aspects of conditional handover for user equipment (UE) are illustrated. For example, the reception may be performed by component 198, transceiver 922 and / or antenna 980. The conditional handover configuration may be included in a radio resource control message and indicate one or more of: a plurality of candidate target PCells, a corresponding conditional handover execution condition for each of the plurality of candidate target PCells, a set of a plurality of candidate target PSCells for each of the plurality of candidate target PCells, a corresponding PSCell selection execution condition for each of the plurality of candidate target PSCells, a target configuration of MCG and SCG for each combination of candidate target PCell and candidate target PSCell, or a combination thereof. The conditional handover configuration may also include a measurement configuration from a source MN, wherein each corresponding PSCell selection execution condition is indicated using a measurement identifier (ID) associated with the measurement configuration from the source MN.

[0098] At 504, in response to satisfying the conditional handover execution condition, a conditional handover is performed from the source PCell to the target PCell from the plurality of candidate target PCells. For example, in response to satisfying the previously configured condition, and in the absence of additional network signaling instructing the UE to perform the handover, such as in the absence of a handover command to the target PCell, the UE performs the CHO. The conditional handover may be performed, for example, by component 198.

[0099] At 506, the UE selects a PSCell from a plurality of candidate target PSCells configured in the conditional handover configuration for the target PCell based on the PSCell selection execution condition. For example, the selection may be performed by component 198.

[0100] At 508, the UE communicates with the network on the target PCell and the selected PSCell. For example, the communication may be performed by component 198, transceiver 922, and / or antenna 980. For example, after a conditional handover, the UE may send and / or receive communications (e.g., data transmissions) with the target PCell and / or the target PSCell.

[0101] In some aspects, the UE may simultaneously initiate evaluation of a conditional handover execution condition (e.g., performing a conditional handover at 504) and a PSCell selection execution condition (e.g., selecting a PSCell at 506). In response to the conditional handover execution condition being satisfied simultaneously with the PSCell selection execution condition, the UE may simultaneously access the target PCell and the selected PSCell. In response to the conditional handover execution condition being satisfied, the UE may access the target PCell while continuing to evaluate the PSCell selection execution condition for a candidate target PSCell associated with the target PCell. After the PSCell selection execution condition is satisfied, the UE may remain on the first PCell until the conditional handover execution condition is satisfied.

[0102] In some aspects, the UE may initiate a conditional handover execution condition evaluation prior to a PSCell selection execution condition evaluation. The UE may initiate a PSCell selection execution condition evaluation in response to completion of a portion of a trigger time (TTT) corresponding to a continuous time period during which the conditional handover execution condition will be satisfied for the conditional handover to occur. In some aspects, the conditional handover configuration may indicate a portion of the TTT. In some aspects, the portion of the TTT may be selected by the UE.

[0103] Figure 6 600 is a flow chart of a wireless communication method. The method may be performed by a source MN (e.g., base station 102, 310; source MN 404; network entity 1002). The method may help improve the mobility of a UE served by a wireless network by configuring multiple candidate PSCells for the UE, which increases the likelihood that the UE will be able to access a candidate PSCell with good radio link quality when performing CHO. Therefore, the method may help provide continuity of service and improve communication between the UE and the network.

[0104] At 602, the source MN provides a request for conditional handover including UE measurement information to at least one target MN. In some aspects, the request from the source MN indicates a maximum number of candidate target PSCells for each of the at least one target MN. Figure 4 Various aspects of an example conditional handover for a UE are illustrated. The provision of the request may be performed, for example, by component 199, transceiver 1046, and / or antenna 1080.

[0105] At 604, the source MN receives a response from each of the at least one target MN indicating a plurality of candidate target PSCells associated with the candidate target PCell. The receiving may be performed by component 199, transceiver 1046, and / or antenna 1080, for example.

[0106] At 606, the source MN configures a conditional handover configuration for the UE to hand over to one of the multiple candidate target PCells, and includes multiple candidate target PSCells associated with each candidate target PCell in the configuration. For example, the configuration may be performed by component 199, transceiver 1046, and / or antenna 1080. The conditional handover configuration may be included in a radio resource control message and indicate one or more of: multiple candidate target PCells, corresponding conditional handover execution conditions for each of the multiple candidate target PCells, a set of multiple candidate target PSCells for each of the multiple candidate target PCells, corresponding PSCell selection execution conditions for each of the multiple candidate target PSCells, or a target configuration of a primary cell group (MCG) and a secondary cell group (SCG) for each combination of a candidate target PCell and a candidate target PSCell. The conditional handover configuration may also include a measurement configuration from a source master node (MN), wherein each corresponding PSCell selection execution condition is indicated using a measurement identifier (ID) associated with the measurement configuration from the source MN.

[0107] Fig. 7A 700 is a flowchart of a method of wireless communication. The method may be performed by a network node (e.g., base station 102, 310; target MN 406; network entity 1002). The method may help improve the mobility of a UE served by a wireless network by configuring a plurality of candidate PSCells for the UE, which increases the likelihood that the UE will be able to access a candidate PSCell with good radio link quality when performing CHO. Therefore, the method may help provide continuity of service and improve communication between the UE and the network.

[0108] At 702, the target MN receives a request associated with a conditional handover from a source MN, the request identifying a candidate target PCell and including UE measurement information. In some aspects, the request from the source MN may indicate to the target MN a maximum number of candidate target PSCells. In some aspects, the request for conditional handover indicates one or more of: a suggested set of PSCells based on UE measurement information provided by the source MN in the request for conditional handover, a source secondary node identifier, or a source SCG configuration. Figure 4 An example of a conditional handover is illustrated. For example, the receiving may be performed by component 199, transceiver 1046, and / or antenna 1080.

[0109] At 704, the target MN indicates to the source MN a plurality of candidate target PSCells associated with the candidate target PCell for conditional handover. The indicating may be performed by component 199, transceiver 1046, and / or antenna 1080, for example.

[0110] Figure 7B 750 is a flow chart of a method of wireless communication. The method may be performed by a network node (eg, base station 102, 310; target MN 406; network entity 1002). Fig. 7A Similar aspects are illustrated with the same reference numerals. Figure 7B In some aspects, the target MN may also send additional requests associated with the conditional handover to one or more candidate target secondary nodes at 701. For example, the sending may be performed by component 199, transceiver 1046, and / or antenna 1080. In some aspects, the request for conditional handover may indicate one or more of: a suggested set of PSCells based on UE measurement information provided by the source MN in the request for conditional handover, a source secondary node identifier, or a source SCG configuration.

[0111] At 703, the target MN may receive a response from at least one of the one or more candidate target secondary nodes. At 704, the multiple candidate target PSCells indicated to the source MN may be based on a response from at least one of the one or more candidate target secondary nodes. In some aspects, the response may include one or more of the following: a set of candidate target PSCells associated with the target MN, or a target secondary cell group (SCG) configuration associated with each PSCell in the set of candidate target PSCells. For example, the reception may be performed by component 199, transceiver 1046, and / or antenna 1080. In some aspects, the response may include one or more of the following: a set of candidate target PSCells associated with the target MN, or a target SCG configuration associated with each PSCell in the set of candidate target PSCells.

[0112] Figure 8 800 is a flow chart of a wireless communication method. The method may be performed by a network node (e.g., base station 102, 310; target SN 408; network entity 1002). The method may help improve the mobility of a UE served by a wireless network by configuring multiple candidate PSCells for the UE, which increases the likelihood that the UE will be able to access a candidate PSCell with good radio link quality when performing CHO. Therefore, the method may help provide continuity of service and improve communication between the UE and the network.

[0113] At 802, the target SN receives an attach request associated with a conditional handover for a user equipment from a target MN. In some aspects, the request indicates one or more of: a suggested set of PSCells, a source secondary node identifier, or a source SCG configuration. Figure 4 Various aspects associated with conditional handover are illustrated. For example, the receiving can be performed by component 199, transceiver 1046, and / or antenna 1080.

[0114] At 804, the target SN sends a response to the target MN indicating a plurality of candidate target PSCells associated with a conditional handover to the target MN. In some aspects, the response includes one or more of: a set of candidate target PSCells associated with the target MN, or a target SCG configuration associated with each PSCell in the set of candidate target PSCells. For example, the sending may be performed by component 199, transceiver 1046, and / or antenna 1080.

[0115] Fig. 9900 is a diagram illustrating an example of a hardware implementation for an apparatus 904. The apparatus 904 may be a UE, a component of a UE, or may implement UE functionality. In some aspects, the apparatus 904 may include at least one cellular baseband processor 924 (or processor circuit) (also referred to as a modem) coupled to one or more transceivers 922 (e.g., a cellular RF transceiver). The RU processor 924 may include at least one cellular baseband processor 924' (or memory circuit). In some aspects, the apparatus 904 may also include one or more subscriber identity module (SIM) cards 920 and at least one application processor 906 (or processor circuit) coupled to a secure digital (SD) card 908 and a screen 910. The application processor 906 may include on-chip memory 906' (or memory circuit). In some aspects, the device 904 may also include a Bluetooth module 912, a WLAN module 914, an SPS module 916 (e.g., a GNSS module), one or more sensor modules 918 (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 926, a power source 930, and / or a camera 932. The Bluetooth module 912, the WLAN module 914, and the SPS module 916 may include an on-chip transceiver (TRX) (or in some cases, only a receiver (RX)). The Bluetooth module 912, the WLAN module 914, and the SPS module 916 may include their own dedicated antennas and / or communicate using an antenna 980. The cellular baseband processor 924 communicates with the UE 104 and / or with the RU associated with the network entity 902 through the transceiver 922 via one or more antennas 980. The cellular baseband processor 924 and the application processor 906 may each include a computer-readable medium / memory 924', 906', respectively. The additional memory module 926 may also be considered as a computer-readable medium / memory. Each computer-readable medium / memory 924', 906', 926 may be non-transitory. The cellular baseband processor 924 and the application processor 906 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 924 / application processor 906, enables the cellular baseband processor 924 / application processor 906 to perform the various functions described above. The cellular baseband processor 924 and the application processor 906 are configured to perform the various functions described above based at least in part on the information stored in the memory.That is, the cellular baseband processor 924 and the application processor 906 may be configured to perform a first subset of the various functions described above without information stored in the memory, and may be configured to perform a second subset of the various functions described above based on the information stored in the memory. The computer-readable medium / memory may also be used to store data manipulated by the cellular baseband processor 924 / application processor 906 when executing software. The cellular baseband processor 924 / application processor 906 may be a component of the UE 350 and may include at least one of the memory 360 and / or the TX processor 368, the RX processor 356, and the controller / processor 359. In one configuration, the device 904 may be a processor chip (modem and / or application) and includes only the cellular baseband processor 924 and / or the application processor 906, and in another configuration, the device 904 may be the entire UE (e.g., see. Figure 3 350) and includes additional modules of device 904.

[0116] As discussed above, the CHO component 198 is configured to receive a conditional handover configuration for handover to one of a plurality of candidate target PCells, the conditional handover configuration including a plurality of candidate target PSCells associated with each candidate target PCell in the conditional handover configuration; in response to satisfying a conditional handover execution condition, perform a conditional handover from a source PCell to a target PCell from the plurality of candidate target PCells; based on a PSCell selection execution condition, select a PSCell from the plurality of candidate target PSCells configured in the conditional handover configuration for the target PCell; and communicate with the network on the target PCell and the selected PSCell. The CHO component 198 may be configured to perform a combination of Figure 5 Any of the aspects described and / or Figure 4Any of the various aspects performed by the UE in the . Component 198 may be within the cellular baseband processor 924, the application processor 906, or both the cellular baseband processor 924 and the application processor 906. Component 198 may be one or more hardware components that are specifically configured to perform the stated process / algorithm, implemented by one or more processors configured to perform the stated process / algorithm, stored in a computer-readable medium for implementation by one or more processors, or some combination of the above. When multiple processors are implemented, the multiple processors may execute the stated process / algorithm individually or in combination. As shown, the device 904 may include multiple components configured for various functions. In one configuration, the device 904 (particularly the cellular baseband processor 924 and / or the application processor 906) includes a component for receiving a conditional handover configuration for handover to one of a plurality of candidate target PCells and including a plurality of candidate target PSCells associated with each candidate target PCell in the conditional handover configuration; a component for performing a conditional handover from a source PCell to a target PCell from a plurality of candidate target PCells in response to satisfying a conditional handover execution condition; a component for selecting a PSCell from a plurality of candidate target PSCells configured in the conditional handover configuration for the target PCell based on a PSCell selection execution condition; and a component for communicating with the network on the target PCell and the selected PSCell. The device 904 may also include a component for performing a combined handover. Figure 5 Any of the aspects described and / or Figure 4 Components of any of the aspects performed by the UE in the apparatus 904. The components may be components 198 of the apparatus 904 configured to perform the functions recited by the components. As described above, the apparatus 904 may include a TX processor 368, an RX processor 356, and a controller / processor 359. Therefore, in one configuration, the components may be the TX processor 368, the RX processor 356, and / or the controller / processor 359 configured to perform the functions recited by the components.

[0117] Fig.101000 is a diagram illustrating an example of a hardware implementation for a network entity 1002. The network entity 1002 may be a BS, a component of a BS, or may implement BS functionality. The network entity 1002 may include at least one of a CU 1010, a DU 1030, or a RU 1040. For example, depending on the layer functionality handled by the component 199, the network entity 1002 may include a CU 1010; both a CU 1010 and a DU 1030; each of the CU 1010, the DU 1030, and the RU 1040; the DU 1030; both a DU 1030 and a RU 1040; or the RU 1040. The CU 1010 may include at least one CU processor 1012 (or processor circuit). The CU processor 1012 may include at least one on-chip memory 1012' (or memory circuit). In some aspects, the CU 1010 may also include an additional memory module 1014 and a communication interface 1018. CU 1010 communicates with DU 1030 via a midhaul link (such as an F1 interface). DU 1030 may include at least one DU processor 1032 (or processor circuit). DU processor 1032 may include on-chip memory 1032' (or memory circuit). In some aspects, DU 1030 may also include additional memory modules 1034 and communication interfaces 1038. DU 1030 communicates with RU 1040 via a fronthaul link. RU 1040 may include at least one RU processor 1042 (or processor circuit). RU processor 1042 may include at least one on-chip memory 1042' (or memory circuit). In some aspects, RU 1040 may also include additional memory modules 1044, one or more transceivers 1046, antennas 1080, and communication interfaces 1048. RU 1040 communicates with UE 104. On-chip memory 1012 ', 1032 ', 1042 ' and additional memory modules 1014, 1034, 1044 can each be considered a computer readable medium / memory. Each computer readable medium / memory can be non-transitory. Each of the processors 1012, 1032, 1042 is responsible for general processing, including executing software stored on the computer readable medium / memory. The software, when executed by the corresponding processor, enables the processor to perform the various functions described above. The computer readable medium / memory can also be used to store data manipulated by the processor when executing the software.

[0118] As discussed above, the CHO component 199 can be configured to, for example, provide a request for conditional handover including UE measurement information to at least one target MN when the network entity is operating at the source MN; receive a response indicating multiple candidate target PSCells associated with the candidate target PCell from each of the at least one target MN; and configure a conditional handover configuration for the UE to hand over to one of the multiple candidate target PCells, and include multiple candidate target PSCells associated with each candidate target PCell in the configuration. The CHO component 199 can also be configured to perform a combination of Figure 6 The various aspects described by the flowcharts in and / or by Figure 4 The CHO component may be configured to, for example, when the network entity operates as a target MN, receive a request associated with a conditional handover from the source MN, the request identifying a candidate target PCell and including UE measurement information; and indicate to the source MN a plurality of candidate target PSCells associated with the candidate target PCell for the conditional handover. The CHO component may also be configured to perform a combined Fig. 7A or Figure 7B The aspects described and / or Figure 4 The CHO component 199 may be configured to, for example, when the network entity operates as a target SN, receive an additional request associated with a conditional handover for a user equipment from a target MN; and send a response to the target MN indicating a plurality of candidate target PSCells associated with the conditional handover. The CHO component may also be configured to perform a combination of Figure 8 The aspects described and / or Figure 4 Any of the aspects performed by the target SN in the network. Component 199 may be within one or more processors of one or more of CU 1010, DU 1030, and RU 1040. Component 199 may be one or more hardware components that are specifically configured to perform the stated process / algorithm, implemented by one or more processors configured to perform the stated process / algorithm, stored in a computer-readable medium for implementation by one or more processors, or some combination of the above. When multiple processors are implemented, the multiple processors may perform the stated process / algorithm individually or in combination. Network entity 1002 may include multiple components configured for various functions. In one configuration, network entity 1002 includes a processor for performing a combination of Figure 6 , Figure 7 and / or Figure 8 The flowcharts described and / or combined Figure 4Components of any of the aspects described in the source MN, target MN and / or target SN in the embodiment of the present invention. Sometimes, the network entity can operate as a source MN. At other times, the network entity can operate as a target MN. At other times, the network entity can operate as a target SN. For example, if the network entity operates as a source MN, and can include a component for providing a request for conditional handover including UE measurement information to at least one target MN; a component for receiving a response indicating multiple candidate target PSCells associated with the candidate target PCell from each target MN in the at least one target MN; and a component for configuring a conditional handover configuration for the UE to hand over to one of the multiple candidate target PCells, and including multiple candidate target PSCells associated with each candidate target PCell in the configuration. In some aspects, the network entity can operate as a target MN, and can include a component for receiving a request associated with conditional handover from a source MN, the request identifying the candidate target PCell and including UE measurement information; and a component for indicating to the source MN multiple candidate target PSCells associated with the candidate target PCell for conditional handover. In some aspects, the network entity may also include a component for sending an additional request associated with the conditional handover to one or more candidate target secondary nodes; and a component for receiving a response from at least one of the one or more candidate target secondary nodes, the multiple candidate target PSCells indicated to the source MN are based on the response from at least one of the one or more candidate target secondary nodes. In some aspects, the network entity may operate as a target secondary node and may include a component for receiving an additional request associated with a conditional handover for a user equipment from a target MN; and a component for sending a response indicating multiple candidate target PSCells associated with the conditional handover to the target MN. The component may be a component 199 of the network entity 1002 configured to perform the functions recorded by the component. As described above, the network entity 1002 may include a TX processor 316, an RX processor 370, and a controller / processor 375. Therefore, in one configuration, the component may be a TX processor 316, an RX processor 370, and / or a controller / processor 375 configured to perform the functions recorded by the component.

[0119] It should be understood that the specific order or hierarchy of the blocks in the disclosed process / flowchart is merely an illustration of the exemplary method. It should be understood that the specific order or hierarchy of the blocks in the process / flowchart may be rearranged based on design preferences. Further, some blocks may be combined or omitted. The attached method claims provide the elements of the various blocks in a sample order, but are not limited to the specific order or hierarchy provided.

[0120] 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 can 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 "while" do not mean a direct temporal relationship or reaction. That is, these phrases, such as "when ......", do not mean an immediate action in response to the occurrence of an action or during the occurrence of an action, but simply imply that if the conditions are met, the action will occur, but no specific or immediate time limit is required for the occurrence of the action. 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 advantages 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, which may include multiple A, multiple B, or multiple C. Specifically, combinations such as "at least one of A, B, or C", "one or more of A, B, or C", "at least one of A, B, and C", "one or more of A, B, and C", and "A, B, C, or any combination thereof" 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. When at least one processor is configured to perform a set of functions, the at least one processor is configured to perform the set of functions individually or in any combination. Thus, each of the at least one processor may be configured to perform a specific subset of the set of functions, where the subset is a complete set, a proper subset of the set, or an empty subset of the set. If a first device receives data from a second device or sends data to a second device, the data may be received / sent directly between the first device and the second device, or indirectly between the first device and the second device through a collection of devices. A device configured to "output" or "provide" data (such as, transmit, signal, or message) may, for example, send the data using a transceiver, or may transmit the data to a device that sends the data.A device configured to "obtain" data (such as, transmit, signal or message) may, for example, receive data with a transceiver, or may obtain the data from a device that receives the data. The information stored in the memory includes instructions and / or data. All structural and functional equivalents of the elements of the various aspects described throughout the present 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" 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..."

[0121] 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.

[0122] The following aspects are merely illustrative and may be combined with other aspects or teachings described herein without limitation.

[0123] Aspect 1 is a method for performing wireless communication at a UE, the method comprising: receiving a conditional handover configuration for handover to one candidate target PCell among multiple candidate target PCells, the conditional handover configuration comprising multiple candidate target PSCells associated with each candidate target PCell in the conditional handover configuration; in response to satisfying a conditional handover execution condition, performing a conditional handover from a source PCell to a target PCell from the multiple candidate target PCells; based on a PSCell selection execution condition, selecting a PSCell from the multiple candidate target PSCells configured in the conditional handover configuration for the target PCell; and communicating with a network on the target PCell and the selected PSCell.

[0124] In aspect 2, the method according to aspect 1 also includes the conditional handover configuration being included in a radio resource control message and indicating one or more of the following: the multiple candidate target PCells, the corresponding conditional handover execution conditions for each of the multiple candidate target PCells, the set of the multiple candidate target PSCells for each of the multiple candidate target PCells, the corresponding PSCell selection execution conditions for each of the multiple candidate target PSCells, the target configuration of MCG and SCG for each combination of candidate target PCell and candidate target PSCell, or a combination thereof.

[0125] In aspect 3, the method according to aspect 2 further comprises the conditional handover configuration comprising: a measurement configuration from a source MN, wherein each corresponding PSCell selection execution condition is indicated using a measurement ID associated with the measurement configuration from the source MN.

[0126] In aspect 4, the method according to any one of aspects 1 to 3 further comprises initiating evaluation of the conditional handover execution condition and the PSCell selection execution condition simultaneously.

[0127] In aspect 5, the method according to aspect 4 also includes simultaneously accessing the target PCell and the selected PSCell in response to the conditional handover execution condition being satisfied simultaneously with the PSCell selection execution condition; accessing the target PCell while continuing to evaluate the PSCell selection execution condition for the candidate target PSCell associated with the target PCell in response to the conditional handover execution condition being satisfied; or, after the PSCell selection execution condition is satisfied, remaining on the source PCell until the conditional handover execution condition is satisfied.

[0128] In aspect 6, the method according to any one of aspects 1 to 3 further comprises initiating a conditional handover execution condition evaluation before the PSCell selection execution condition evaluation.

[0129] In aspect 7, the method according to aspect 6 further comprises initiating the PSCell selection execution condition evaluation in response to completion of a portion of the TTT corresponding to a continuous time period, during which the conditional handover execution condition will be satisfied for the conditional handover to occur.

[0130] In aspect 8, the method according to aspect 7 further comprises the conditional handover configuration indicating the portion of the TTT.

[0131] In aspect 9, the method according to aspect 7 further comprises the portion of the TTT being selected by the UE.

[0132] Aspect 10 is an apparatus for performing wireless communications at a UE, the apparatus comprising: at least one memory; and at least one processor, the at least one processor being coupled to the at least one memory and being configured, alone or in any combination, to cause the UE to perform a method according to any one of Aspects 1 to 9 based at least in part on information stored in the at least one memory.

[0133] Aspect 11 is an apparatus for wireless communication at a user equipment, the apparatus comprising means for performing each step in the method according to any one of aspects 1 to 9.

[0134] Aspect 12 is the apparatus of any one of Aspects 10 to 11, further comprising a transceiver configured to receive or transmit in association with the method of any one of Aspects 1 to 9.

[0135] Aspect 13 is a computer-readable medium storing computer-executable code at a UE, which, when executed by at least one processor, causes the UE to perform the method of any one of aspects 1 to 9.

[0136] Aspect 14 is a method for performing wireless communication at a source MN, the method comprising: providing a request for conditional handover including UE measurement information to at least one target MN; receiving a response indicating multiple candidate target PSCells associated with the candidate target PCell from each of the at least one target MN; and configuring a conditional handover configuration for the UE for handover to one of the multiple candidate target PCells, and including the multiple candidate target PSCells associated with each candidate target PCell in the conditional handover configuration.

[0137] In aspect 15, the method according to aspect 14 also includes the conditional handover configuration being included in the RRC message and indicating one or more of the following: the multiple candidate target PCells, the corresponding conditional handover execution conditions for each of the multiple candidate target PCells, the set of the multiple candidate target PSCells for each of the multiple candidate target PCells, the corresponding PSCell selection execution conditions for each of the multiple candidate target PSCells, the target configuration of MCG and SCG for each combination of candidate target PCell and candidate target PSCell, or a combination thereof.

[0138] In aspect 16, the method according to aspect 15 further comprises the conditional handover configuration comprising: a measurement configuration from the source MN, wherein each corresponding PSCell selection execution condition is indicated using a measurement ID associated with the measurement configuration from the source MN.

[0139] In aspect 17, the method according to any one of aspects 14 to 16 further comprises the request from the source MN further indicating a maximum number of candidate target PSCells for each of the at least one target MN.

[0140] Aspect 18 is an apparatus for performing wireless communication at a source MN, the apparatus comprising: at least one memory; and at least one processor, the at least one processor being coupled to the at least one memory and being configured, alone or in any combination, to cause the source MN to perform a method according to any one of Aspects 14 to 17 based at least in part on information stored in the at least one memory.

[0141] Aspect 19 is an apparatus for wireless communication at a source MN, the apparatus comprising means for performing each step in the method of any one of aspects 14 to 17.

[0142] Aspect 20 is the apparatus of any one of aspects 18 or 19, further comprising a transceiver configured to receive or transmit in association with the method of any one of aspects 14 to 17.

[0143] Aspect 21 is a computer-readable medium storing computer executable codes at a source MN, which, when executed by at least one processor, causes the source MN to perform the method of any one of aspects 14 to 17.

[0144] Aspect 22 is a method for performing wireless communication at a target MN, the method comprising: receiving a request associated with a conditional handover from a source MN, the request identifying a candidate target PCell and including UE measurement information; and indicating to the source MN a plurality of candidate target PSCells associated with the candidate target PCell for the conditional handover.

[0145] In aspect 23, the method according to aspect 22 further comprises the request from the source MN indicating to the target MN a maximum number of candidate target PSCells.

[0146] In aspect 24, the method according to aspect 22 or 23 also includes sending an additional request associated with the conditional handover to one or more candidate target secondary nodes; and receiving a response from at least one of the one or more candidate target secondary nodes, and the multiple candidate target PSCells indicated to the source MN are based on the response from the at least one of the one or more candidate target secondary nodes.

[0147] In aspect 25, the method according to aspect 24 also includes indicating, in the request for the conditional handover, one or more of: a recommended set of PSCells based on the UE measurement information provided by the source MN in the request for the conditional handover, a source secondary node identifier, or a source SCG configuration.

[0148] In aspect 26, the method according to aspect 24 or 25 also includes the response comprising one or more of the following: a set of candidate target PSCells associated with the target MN, or a target SCG configuration associated with each PSCell in the set of candidate target PSCells.

[0149] Aspect 27 is an apparatus for performing wireless communication at a target MN, the apparatus comprising: at least one memory; and at least one processor, the at least one processor being coupled to the at least one memory and being configured, alone or in any combination, to cause the target MN to perform a method according to any one of Aspects 22 to 26 based at least in part on information stored in the at least one memory.

[0150] Aspect 28 is an apparatus for wireless communication at a target MN, the apparatus comprising means for performing each step in the method of any one of aspects 22 to 26.

[0151] Aspect 29 is the apparatus of any one of Aspects 27 or 28, further comprising a transceiver configured to receive or transmit in association with the method of any one of Aspects 22 to 26.

[0152] Aspect 30 is a computer-readable medium storing computer-executable code at a target MN, which, when executed by at least one processor, causes the target MN to perform the method of any one of aspects 22 to 26.

[0153] Aspect 31 is a method of wireless communication at a target SN, the method comprising: receiving an attach request associated with a conditional handover for a user equipment from a target MN; and sending a response to the target MN indicating a plurality of candidate target PSCells associated with the conditional handover.

[0154] In aspect 32, the method according to aspect 30 further comprises the request indicating one or more of: a suggested set of PSCells, a source secondary node identifier, or a source SCG configuration.

[0155] In aspect 33, the method according to aspect 30 or 31 also includes the response including one or more of the following: a set of candidate target PSCells associated with the target MN, or a target SCG configuration associated with each PSCell in the set of candidate target PSCells.

[0156] Aspect 34 is an apparatus for performing wireless communication at a target SN, the apparatus comprising: at least one memory; and at least one processor, the at least one processor being coupled to the at least one memory and being configured, alone or in any combination, to cause the target SN to perform a method according to any one of Aspects 31 to 33 based at least in part on information stored in the at least one memory.

[0157] Aspect 35 is an apparatus for wireless communication at a target SN, the apparatus comprising means for performing each step in the method of any one of Aspects 31 to 33.

[0158] Aspect 36 is an apparatus according to any one of Aspects 34 or 35, the apparatus further comprising a transceiver configured to receive or transmit in association with the method according to any one of Aspects 31 to 33.

[0159] Aspect 37 is a computer-readable medium (e.g., a non-transitory computer-readable medium) storing computer-executable code at a target SN, which, when executed by at least one processor, causes the target SN to perform the method of any one of Aspects 31 to 33.

Claims

1. An apparatus for wireless communication at a user equipment (UE), the apparatus comprising: at least one memory; as well as at least one processor, the at least one processor being coupled to the at least one memory and, based at least in part on the information stored in the at least one memory, the at least one processor being configured, alone or in any combination, to cause the UE to: Receiving a conditional handover configuration for handover to a candidate target primary cell (PCell) among a plurality of candidate target PCells, the conditional handover configuration comprising a plurality of candidate target primary secondary cells (PSCells) associated with each candidate target PCell in the conditional handover configuration; In response to satisfying a conditional handover execution condition, performing a conditional handover from the source PCell to a target PCell from the plurality of candidate target PCells; selecting a PSCell from the plurality of candidate target PSCells configured in the conditional handover configuration for the target PCell based on a PSCell selection execution condition; as well as Communicate with a network on the target PCell and the selected PSCell.

2. The device according to claim 1, further comprising: at least one transceiver coupled to the at least one processor, wherein the conditional handover configuration is included in a radio resource control message and indicates one or more of: The multiple candidate target PCells, A corresponding conditional handover execution condition for each candidate target PCell in the plurality of candidate target PCells, a set of the plurality of candidate target PSCells for each candidate target PCell in the plurality of candidate target PCells, selecting an execution condition for a corresponding PSCell of each candidate target PSCell in the plurality of candidate target PSCells, target configuration of a primary cell group (MCG) and a secondary cell group (SCG) for each combination of a candidate target PCell and a candidate target PSCell, or A combination of them.

3. The apparatus according to claim 2, wherein the conditional handover configuration comprises: A measurement configuration from a source master node (MN), wherein each corresponding PSCell selection execution condition is indicated using a measurement identifier (ID) associated with the measurement configuration from the source MN.

4. The apparatus of claim 1 , wherein the at least one processor is further configured to cause the UE to: At the same time, the evaluation of conditional handover execution conditions and PSCell selection execution conditions is initiated.

5. The apparatus of claim 4, wherein the at least one processor is further configured to cause the UE to perform one of the following: In response to the conditional handover execution condition being satisfied simultaneously with the PSCell selection execution condition, accessing the target PCell and the selected PSCell simultaneously; In response to satisfying the conditional handover execution condition, accessing the target PCell while continuing to evaluate the PSCell selection execution condition for a candidate target PSCell associated with the target PCell; or After the PSCell selection execution condition is met, the PSCell remains on the source PCell until the conditional handover execution condition is met.

6. The apparatus of claim 1, wherein the at least one processor is further configured to cause the UE to: A conditional handover execution condition evaluation is initiated before the PSCell selects an execution condition evaluation.

7. The apparatus of claim 6, wherein the at least one processor is further configured to cause the UE to: The PSCell selection execution condition evaluation is initiated in response to completion of a portion of a time to trigger (TTT) corresponding to a continuous time period during which the conditional handover execution condition is to be satisfied for the conditional handover to occur. The apparatus of claim 7 , wherein the conditional handover configuration indicates the portion of the TTT.

9. The apparatus of claim 7, wherein the portion of the TTT is selected by the UE.

10. The apparatus of claim 1, further comprising at least one transceiver coupled to the at least one processor, wherein the at least one processor is configured to cause the UE to transmit or receive via the at least one transceiver.

11. An apparatus for wireless communication at a source master node (MN), the apparatus comprising: at least one memory; as well as at least one processor coupled to the at least one memory and, based at least in part on information stored in the at least one memory, configured, alone or in any combination, to cause the source MN to: providing a request for conditional handover including UE measurement information to at least one target MN; Receiving from each of the at least one target MN an indication and a candidate target primary cell (PCell) Responses of multiple candidate target primary and secondary cells (PSCells) associated with the target cell; as well as A conditional handover configuration for handover to one of a plurality of candidate target PCells is configured for a user equipment (UE), and the plurality of candidate target PSCells associated with each candidate target PCell are included in the conditional handover configuration.

12. The device according to claim 11, further comprising: at least one transceiver coupled to the at least one processor, wherein the conditional handover configuration is included in a radio resource control (RRC) message and indicates one or more of: The multiple candidate target PCells, A corresponding conditional handover execution condition for each candidate target PCell in the plurality of candidate target PCells, a set of the plurality of candidate target PSCells for each candidate target PCell in the plurality of candidate target PCells, selecting an execution condition for a corresponding PSCell of each candidate target PSCell in the plurality of candidate target PSCells, target configuration of a primary cell group (MCG) and a secondary cell group (SCG) for each combination of a candidate target PCell and a candidate target PSCell, or A combination of them.

13. The apparatus of claim 12, wherein the conditional handover configuration comprises: A measurement configuration from the source MN, wherein each corresponding PSCell selection execution condition is indicated using a measurement identifier (ID) associated with the measurement configuration from the source MN.

14. The apparatus of claim 11, wherein the request from the source MN further indicates a maximum number of candidate target PSCells for each of the at least one target MN.

15. The apparatus of claim 11, further comprising at least one transceiver coupled to the at least one processor, wherein the at least one processor is configured to cause the source master node to transmit or receive via the at least one transceiver.

16. An apparatus for wireless communication at a target master node (MN), the apparatus comprising: at least one memory; as well as at least one processor coupled to the at least one memory and, based at least in part on information stored in the at least one memory, the at least one processor configured, alone or in any combination, to cause the target MN to: receiving a request associated with a conditional handover from a source MN, the request identifying a candidate target primary cell (PCell) and including UE measurement information; as well as A plurality of candidate target primary and secondary cells (PSCells) associated with the candidate target PCell for the conditional handover are indicated to the source MN.

17. The apparatus of claim 16, wherein the request from the source MN indicates a maximum number of candidate target PSCells to the target MN.

18. The apparatus according to claim 16, further comprising: at least one transceiver coupled to the at least one processor, wherein the at least one processor is further configured to cause the target MN to: sending an additional request associated with the conditional handover to one or more candidate target secondary nodes; and A response is received from at least one of the one or more candidate target secondary nodes, the plurality of candidate target PSCells indicated to the source MN being based on the response from the at least one of the one or more candidate target secondary nodes.

19. The apparatus of claim 18, wherein the request for the conditional handover indicates one or more of: a suggested set of PSCells, the suggested set of PSCells being based on the UE measurement information provided by the source MN in the request for the conditional handover, The source slave node identifier, or Source Secondary Cell Group (SCG) configuration.

20. The apparatus of claim 19, wherein the response comprises one or more of: a set of candidate target PSCells, the set of candidate target PSCells being associated with the target MN, or A target secondary cell group (SCG) configuration is associated with each PSCell in the set of candidate target PSCells.

21. The apparatus of claim 16, further comprising at least one transceiver coupled to the at least one processor, wherein the at least one processor is configured to cause the target host node to transmit or receive via the at least one transceiver.

22. An apparatus for wireless communication at a target secondary node (SN), the apparatus comprising: at least one memory; as well as at least one processor coupled to the at least one memory and, based at least in part on information stored in the at least one memory, the at least one processor, alone or in any combination, configured to cause the SN to: receiving an attach request associated with a conditional handover for a user equipment from a target master node (MN); and A response is sent to the target MN indicating a plurality of candidate target primary and secondary cells (PSCells) associated with the conditional handover.

23. The apparatus according to claim 22, further comprising: at least one transceiver coupled to the at least one processor, wherein the additional request indicates one or more of: PSCell's collection of suggestions, The source secondary node identifier, or Source Secondary Cell Group (SCG) configuration.

24. The apparatus of claim 23, wherein the response comprises one or more of: a set of candidate target PSCells, the set of candidate target PSCells being associated with the target MN, or A target secondary cell group (SCG) configuration is associated with each PSCell in the set of candidate target PSCells.

25. The apparatus of claim 22, further comprising at least one transceiver coupled to the at least one processor, wherein the at least one processor is configured to cause the target secondary node to transmit or receive via the at least one transceiver.

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