Radio link management for sidelink carrier aggregation component carriers

Abstract

The first UE may establish a sidelink connection with the at least one second UE via the first PCC. The first PCC and a first set of SCCs may be associated with a first transmission of the first UE. The sidelink connection with the at least one second UE may be associated with carrier aggregation. The first UE may detect at least one of (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) the first set of SCCs is capable of maintaining the sidelink connection, and send a first indication of the at least one. The first UE may receive, based on the first indication, a second indication of a handover of the sidelink connection from the first PCC to a first SCC of a first set of SCCs.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. patent application serial number 17 / 805,416, filed on June 3, 2022, entitled “RADIO LINK MANAGEMENT FOR SIDELINK CARRIER AGGREGATION COMPONENT CARRIERS,” which is expressly incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates generally to communication systems, and more particularly to sidelink radio link management (RLM) systems. 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 city, country, region, and even global levels. 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] The following presents a summary of one or more aspects in order to provide a basic understanding of these aspects. This summary is not an extensive review of all contemplated aspects. This summary is neither intended to identify the key or important elements of all aspects, nor to describe the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to a more detailed description presented later.

[0007] In one aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may have a memory and at least one processor coupled to the memory at a first user equipment (UE). Based at least in part on information stored in the memory, the at least one processor may be configured to: establish a sidelink connection with at least one second UE via a first primary component carrier (PCC). The first PCC and a first set of secondary component carriers (SCCs) may be associated with a first transmission of the first UE. The sidelink connection with the at least one second UE may be associated with carrier aggregation (CA). Based at least in part on information stored in the memory, the at least one processor may be configured to: detect at least one of the following: (i) the sidelink connection is associated with an RLF value within an RLF threshold of a radio link failure (RLF) limit, or (ii) at least one SCC in the first set of SCCs is capable of maintaining the sidelink connection. Based at least in part on the information stored in the memory, the at least one processor may be configured to: send a first indication of at least one of: (i) the sidelink connection is associated with the RLF value within the RLF threshold of the RLF limit, or (ii) the at least one SCC in the first set of SCCs is capable of maintaining the sidelink connection. Based at least in part on the information stored in the memory, the at least one processor may be configured to: receive a second indication of a handover of the sidelink connection from the first PCC to the first SCC in the first set of SCCs based on the first indication.

[0008] In another aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may have a memory and at least one processor coupled to the memory at a first UE. Based at least in part on the information stored in the memory, the at least one processor may be configured to: establish a sidelink connection with at least one second UE via at least one second PCC. The at least one second PCC and at least one second set of SCCs may be associated with a second transmission of the at least one second UE. The sidelink connection with the at least one second UE may be associated with carrier aggregation. Based at least in part on the information stored in the memory, the at least one processor may be configured to: detect at least one of the following: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) at least one SCC in at least one second set of SCCs is capable of maintaining the sidelink connection. Based at least in part on the information stored in the memory, the at least one processor may be configured to: send a first indication of at least one of: (i) the sidelink connection is associated with the RLF value within the RLF threshold of the RLF limit, or (ii) the at least one SCC in the at least one second set of SCCs is capable of maintaining the sidelink connection. Based at least in part on the information stored in the memory, the at least one processor may be configured to: receive a second indication of a handover of the sidelink connection from the second PCC to at least a second SCC in the at least one second set of SCCs based on the first indication.

[0009] In another aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may include a memory and at least one processor coupled to the memory at a second UE. Based at least in part on the information stored in the memory, the at least one processor may be configured to establish a sidelink connection with at least one first UE via at least one first PCC. The at least one first PCC and at least one first set of SCCs may be associated with a first transmission of the first UE. The sidelink connection with the at least one first UE may be associated with carrier aggregation. Based at least in part on the information stored in the memory, the at least one processor may be configured to receive a first indication of at least one of the following: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) at least one first set of SCCs is capable of maintaining the sidelink connection. Based at least in part on the information stored in the memory, the at least one processor may be configured to switch the sidelink connection from the at least one first PCC to at least a first SCC in the first set of SCCs based on the first indication. Based at least in part on the information stored in the memory, the at least one processor may be configured to send a second indication of the switching of the sidelink connection from the at least one first PCC to the at least first SCC in the first set of SCCs.

[0010] In another aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may include a memory and at least one processor coupled to the memory at a second UE. Based at least in part on the information stored in the memory, the at least one processor may be configured to establish a sidelink connection with at least one first UE via a second PCC. The second PCC and the second set of SCCs may be associated with a second transmission of the second UE. The sidelink connection with the at least one first UE may be associated with carrier aggregation. Based at least in part on the information stored in the memory, the at least one processor may be configured to receive a first indication of at least one of the following: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) at least one SCC in the second set of SCCs is capable of maintaining the sidelink connection. Based at least in part on the information stored in the memory, the at least one processor may be configured to switch the sidelink connection from the second PCC to a second SCC in the second set of SCCs based on the first indication. Based at least in part on the information stored in the memory, the at least one processor may be configured to send a second indication of the switching of the sidelink connection from the second PCC to the second SCC in the second set of SCCs.

[0011] To achieve the aforementioned and related purposes, one or more aspects include the features fully described below and specifically pointed out in the claims. The following description and the accompanying drawings set forth in detail some exemplary features of one or more aspects. However, these features are only indicative of only some of the various ways in which the principles of the various aspects can be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[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 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 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 is a diagram illustrating example aspects of a time slot structure that may be used for sidelink communications.

[0019] Figure 5 is a diagram illustrating an example of a UE configured with a directional sidelink PCC for transmission between UEs.

[0020] Figure 6 is another diagram illustrating an example of a UE configured with a directional sidelink PCC for transmission between UEs.

[0021] Figure 7 is a connection flow diagram illustrating a radio link management system between two UEs communicating via a D2D communication link.

[0022] Figure 8 is another connection flow diagram illustrating a radio link management system between two UEs communicating via a D2D communication link.

[0023] Fig. 9 is a flow chart of a method of wireless communication.

[0024] Fig.10is another flow chart of a method of wireless communication.

[0025] Fig.11 are diagrams illustrating examples of hardware implementations for example apparatuses and / or network entities. DETAILED DESCRIPTION

[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 blurring such concepts.

[0027] Several aspects of the telecommunication system are also presented with reference to various apparatuses and methods. These apparatuses and methods are described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[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. 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. For example, such computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of these types of computer-readable media, or any other medium that can be used to store computer-executable code in the form of instructions or data structures that can be accessed by a computer.

[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 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, artificial intelligence (AI) enabled devices, 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 can 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) equipment 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 several 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, chip-level components, systems, distributed arrangements, aggregated or disaggregated components, end-user devices, etc., of various sizes, shapes, and configurations.

[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 a network equipment (such as a base station (BS), or one or more units (or one or more components) that perform base station functionality can be implemented in an aggregated 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 clustered 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 (such as a network configuration sponsored by the O-RAN Alliance)), or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN)). Decomposition may include distributing functionality across two or more units at various physical locations, as well as virtually distributing functionality of at least one unit, which may enable flexibility in network design. Individual units of a disaggregated base station or disaggregated RAN architecture may be configured for wired or wireless communication with at least one other unit.

[0034] Figure 11 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, signals) via a wired or wireless transmission medium. Each of the units or an associated processor or controller that provides instructions to the communication interfaces of these units may be configured to communicate with one or more of the other units via 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 that is configured to communicate signals with other control functions hosted by CU 110. CU 110 may be configured to handle user plane functionality (i.e., central unit-user plane (CU-UP)), control plane functionality (i.e., central unit-control plane (CU-CP)), or a combination thereof. In some specific implementations, CU 110 may be logically split into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP unit may communicate bidirectionally with the CU-CP unit via an interface (such as an E1 interface). As needed, CU 110 may be implemented to communicate with DU 130 for network control and signaling.

[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 further 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 and user plane communications with the RU 140 may be controlled by the corresponding DU 130. In some scenarios, this configuration may enable the DU 130 and CU 110 to be implemented in a cloud-based RAN architecture such as a vRAN architecture.

[0039] The SMO framework 105 may be configured to support RAN deployment and configuration 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 instantiating virtualized network elements) via a cloud computing platform interface (such as an O2 interface). Such virtualized network elements may include, but are not limited to, CU 110, DU 130, RU 140, and near-RT RIC 125. In some specific implementations, the SMO framework 105 may communicate with hardware aspects of the 4G RAN such as an open eNB (O-eNB) 111 via the O1 interface. Additionally, in some specific implementations, the SMO framework 105 may communicate directly with one or more RUs 140 via the O1 interface. The SMO framework 105 may also include a non-RT RIC 115 configured to support the functionality of the SMO framework 105 .

[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 in communication with the near-RT RIC 125 (such as via an A1 interface). The near-RT RIC 125 may be configured to include logic functions that enable near-real-time control and optimization of RAN elements and resources via data collection and actions through an interface (such as via an E2 interface) that connects one or more CUs 110, one or more DUs 130, or both, and 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 for 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 pass through one or more carriers. For each carrier allocated in a carrier aggregation of up to YxMHz (x component carriers) for transmission in each direction, the base station 102 / UE 104 may use a spectrum of up to YMHz (e.g., 5MHz, 10MHz, 15MHz, 20MHz, 100MHz, 400MHz, etc.) bandwidth. The 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 to DL compared to UL). The component carrier may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell) and the secondary component carrier may be referred to as a secondary cell (SCell).

[0043] Some UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158, or with other devices such as a roadside unit (RSU) 107 that are configured to communicate using the 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 side link channels, such as a physical side link broadcast channel (PSBCH), a physical side link discovery channel (PSDCH), a physical side link shared channel (PSCCH), and a physical side link control channel (PSCCH). The D2D communication may be through a variety of wireless D2D communication systems, such as, for example, Bluetooth, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

[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 (interchangeably) referred to as the "sub-6 GHz" band in various documents and articles. A similar naming issue sometimes occurs with respect to FR2, which is often (interchangeably) referred to as the "millimeter wave" band in documents and articles, although different from the extremely high frequency (EHF) band (30 GHz-300 GHz) identified as the "millimeter wave" band by the International Telecommunication Union (ITU).

[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 therefore 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 different. The transmit direction and receive direction of the UE 104 may be the same or different.

[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 transmit receive point (TRP), a network node, a network entity, a network equipment, or some other suitable term. The base station 102 may be implemented as an integrated access and backhaul (IAB) node, a relay node, a sidelink node, a clustered (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 processes signaling between UE 104 and the core network 120. AMF 161 supports registration management, connection management, mobility management, and other functions. SMF 162 supports session management and other functions. UPF 163 supports packet routing, packet forwarding, and other functions. UDM 164 supports the generation of authentication and key agreement (AKA) credentials, user identity processing, access authorization, and subscription management. One or more location servers 168 are illustrated as including a gateway mobile location center (GMLC) 165 and a location management function (LMF) 166. However, in general, the one or more location servers 168 may include one or more location / positioning servers, which may include one or more of the GMLC 165, the LMF 166, the position determination entity (PDE), the serving mobile location center (SMLC), the mobile positioning center (MPC), etc. The GMLC 165 and the LMF 166 support UE location services. The GMLC 165 provides an interface for clients / applications (e.g., emergency services) to access UE positioning information. The LMF 166 receives measurements and assistance information from the NG-RAN and the UE 104 via the AMF 161 to calculate the location of the UE 104. The NG-RAN may determine the location of the UE 104 using one or more positioning methods. Positioning the UE 104 may involve signal measurements, position estimation, and optional speed calculations based on these measurements. Signal measurements may be performed by the UE 104 and / or the serving base station 102. The measured signal can 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, an NR signal (e.g., multi-round trip time (multi-RTT), DL angle of departure (DL-AoD), DL time difference of arrival (DL-TDOA), UL time difference of arrival (UL-TDOA), and UL angle of arrival (UL-AoA) positioning) and / or one or more of other systems / signals / sensors.

[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] Reference again Figure 1 In certain aspects, the UE 104 may include a sidelink (SL) carrier aggregation (CA) transmission component 198, which may be configured to establish a sidelink connection with at least one second UE via a first PCC or at least one second PCC. The first PCC and a first set of SCCs may be associated with a first transmission of the SL CA transmission component 198. At least one second PCC and at least one second set of SCCs may be associated with a second transmission of the at least one second UE. The sidelink connection with the at least one second UE may be associated with carrier aggregation. The SL CA transmission component 198 may be further configured to detect at least one of the following: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) at least one SCC in the first set of SCCs or at least one SCC in the at least one second set of SCCs is capable of maintaining the sidelink connection. The SL CA sending component 198 may be further configured to send a first indication of at least one of: (i) the side link connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) at least one SCC in the first set of SCCs or at least one SCC in the at least one second set of SCCs is capable of maintaining the side link connection. The SL CA sending component 198 may be further configured to receive a second indication of a switching of the side link connection from the first PCC to the first SCC in the first set of SCCs or from the at least one second PCC to at least a second SCC in the at least one second set of SCCs based on the first indication.

[0053] In certain aspects, the UE 104 may be configured to include an SL CA receiving component 199, which may be configured to establish a sidelink connection with at least one first UE via a first PCC or a second PCC. The at least one first PCC and at least one first set of SCCs may be associated with a first transmission of the at least one first UE. The second PCC and the second set of SCCs may be associated with a second transmission of the SL CA receiving component 199. The sidelink connection with the at least one first UE may be associated with carrier aggregation. The SL CA receiving component 199 may be further configured to receive a first indication of at least one of: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) at least one SCC in at least one first set of SCCs or at least one SCC in the second set of SCCs is capable of maintaining the sidelink connection. The SL CA receiving component 199 may be further configured to switch the sidelink connection from the at least one first PCC to at least a first SCC in the first set of SCCs, or from the second PCC to a second SCC in the second set of SCCs based on the first indication. The SL CA receiving component 199 may be further configured to send a second indication of a handover of the sidelink connection from at least one first PCC to at least a first SCC in the first set of SCCs or from a second PCC to a second SCC in the second set of SCCs. Although the following description may focus on a radio link management system for a sidelink carrier aggregation component carrier, the concepts described herein may be applicable to radio link management systems for other D2D communication links such as, for example, Bluetooth, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

[0054] Each UE 104 may be configured with a SL CA sending component 198 , a SL CA receiving component 199 , or both a SL CA sending component 198 and a SL CA receiving component 199 .

[0055] 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 2DFIG280 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 2C In 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 slot format is configured for the UE via a received slot format indicator (SFI) (dynamically configured via DL control information (DCI) or semi-statically / statically configured via radio resource control (RRC) signaling). Note that the following description also applies to the 5G NR frame structure as TDD.

[0056] FIG. 2A to FIG. 2D The frame structure is illustrated, and various aspects of the present disclosure may be applicable to other wireless communication technologies that may have different frame structures and / or different channels. A frame (10ms) may be divided into 10 subframes of equal size (1ms). Each subframe may include one or more time slots. A subframe may also include a microslot, which may include 7, 4, or 2 symbols. Each time slot may include 14 or 12 symbols, depending on whether the cyclic prefix (CP) is 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 (also known as a single carrier frequency division multiple access (SC-FDMA) symbol) (for power-limited scenarios; limited to single-stream transmission). The number of slots within a subframe is based on the CP and the parameter set. The parameter set defines the subcarrier spacing (SCS) and effectively defines the symbol length / duration, which is equal to 1 / SCS.

[0057]

[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 of a parameter set μ=2 with a normal CP of 14 symbols per slot and 4 slots per subframe is provided. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is about 16.67 μs. Within a frame set, there may be one or more different bandwidth parts (BWPs) that are frequency-division multiplexed (see Figure 2B ). Each BWP may have a specific parameter set and CP (normal or extended).

[0059] A resource grid may be used to represent the frame structure. Each slot includes a resource block (RB) (also called 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 number of RBs in the system bandwidth and the system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not sent via the PBCH (such as a 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 combs in the comb. 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 buffer status reports (BSRs), power headroom reports (PHRs), and / or UCI.

[0064] Figure 3 300 is a block diagram of a first wireless communication device 310 communicating with a second wireless communication device 350 based on a side link. In some examples, the devices 310 and 350 may communicate based on V2X or other D2D communications. The communication may be based on a side link using a PC5 interface. The devices 310 and 350 may include UEs, RSUs, base stations, etc. Packets may be provided to a controller / processor 375 that implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer.

[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 diagram based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols can then be divided into parallel streams. Each stream can then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., a 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 channel estimator 374 can be used to determine the coding and modulation schemes, as well as for spatial processing. Channel estimates can be derived from reference signals and / or channel condition feedback sent by device 350. Each spatial stream can then be provided to a different antenna 320 via a separate transmitter 318Tx. Each transmitter 318Tx can modulate an RF carrier with a corresponding spatial stream for transmission.

[0066] At the device 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 device 350. If multiple spatial streams are destined for the device 350, the Rx processor 356 can combine them into a single OFDM symbol stream. 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 device 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 device 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 a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer-readable medium. The controller / processor 359 may provide demultiplexing, packet reassembly, decryption, header decompression, and control signal processing between transport channels and logical channels. The controller / processor 359 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operations.

[0068] Similar to the functions described in conjunction with the transmission performed by the device 310, the controller / processor 359 may provide 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 from a reference signal or feedback sent by the device 310 may be used by the Tx processor 368 to select appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the Tx processor 368 may be provided to different antennas 352 via separate transmitters 354Tx. Each transmitter 354Tx may modulate an RF carrier with a corresponding spatial stream for transmission.

[0070] The transmission is processed at device 310 in a manner similar to that described in conjunction with the receiver functionality at device 350. Each receiver 318Rx receives the signal through its corresponding antenna 320. Each receiver 318Rx recovers the information modulated onto the RF carrier and provides the information to an Rx processor 370.

[0071] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer-readable medium. The controller / processor 375 provides demultiplexing between transport channels and logical channels, packet reassembly, decryption, header decompression, control signal processing. 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 Figure 1 The SL CA sending component 198 combines various aspects.

[0073] At least one of the Tx processor 368, the Rx processor 356, and the controller / processor 359 may be configured to perform Figure 1 The SL CA receiving component 199 combines various aspects.

[0074] At least one of the Tx processor 316, the Rx processor 370, and the controller / processor 375 may be configured to perform Figure 1 The SL CA sending component 198 combines various aspects.

[0075] At least one of the Tx processor 316, the Rx processor 370, and the controller / processor 375 may be configured to perform Figure 1 The SL CA receiving component 199 combines various aspects.

[0076] Figure 4 Included are diagrams 400 and 410 illustrating example aspects of a slot structure that may be used for sidelink communications (e.g., between UE 104, RSU 107, etc.). In some examples, the slot structure may be within a 5G / NR frame structure. In other examples, the slot structure may be within an LTE frame structure. Although the following description may focus on 5G NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies. Figure 4The example time slot structure in is only an example, and other side link communications may have different frame structures and / or different channels for side link communications. 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 micro time slot, which may include 7, 4 or 2 symbols. Each time slot may contain 7 or 14 symbols, depending on the time slot configuration. For time slot configuration 0, each time slot may include 14 symbols, and for time slot configuration 1, each time slot may include 7 symbols. Schematic diagram 400 illustrates a single resource block transmitted in a single time slot corresponding to a 0.5ms transmission time interval (TTI). The physical side link control channel may be configured to occupy multiple physical resource blocks (PRBs), for example, 10, 12, 15, 20 or 25 PRBs. PSCCH may be limited to a single subchannel. For example, the PSCCH duration may be configured to be 2 symbols or 3 symbols. For example, a subchannel may include 10, 15, 20, 25, 50, 75, or 100 PRBs. Resources for sidelink transmissions may be selected from a resource pool including one or more subchannels. As a non-limiting example, a resource pool may include between 1 and 27 subchannels. A PSCCH size may be established for a resource pool, for example, between 10%-100% of a subchannel within a duration of 2 symbols or 3 symbols. Figure 4 Diagram 410 in illustrates an example in which the PSCCH occupies approximately 50% of a subchannel as an example to illustrate the concept of the PSCCH occupying a portion of a subchannel. The physical sidelink shared channel (PSCCH) occupies at least one subchannel. In some examples, the PSCCH may include a first portion of sidelink control information (SCI), and the PSCCH may include a second portion of the SCI.

[0077] A resource grid may be used to represent the frame structure. Each time slot may include a resource block (RB) (also called 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. Figure 4 As shown, some of the REs may include control information in the PSCCH and some of the REs may include a demodulation RS (DMRS). At least one symbol may be used for feedback. Figure 4An example is illustrated having two symbols for a physical sidelink feedback channel (PSFCH) with adjacent gap symbols. Symbols before and / or after the feedback may be used for a transition between reception of data and transmission of feedback. The gap enables the device to switch from operating as a transmitting device to preparing to operate as a receiving device, e.g., in a subsequent time slot. As illustrated, data may be sent in the remaining REs. The data may include data messages as described herein. The location of any of the data, DMRS, SCI, feedback, gap symbols, and / or LBT symbols may be different from Figure 4 Illustrated example. In some aspects, multiple time slots can be aggregated together.

[0078] Some examples of sidelink communications may include communications that may be from vehicle to vehicle (V2V), vehicle to infrastructure (V2I) (e.g., from a vehicle-based communication device to a road infrastructure node such as a roadside unit (RSU)), vehicle to network (V2N) (e.g., from a vehicle-based communication device to one or more network nodes such as a base station), vehicle to pedestrian (V2P), cellular vehicle-to-everything (C-V2X), and / or combinations thereof, and / or vehicle-based communication devices communicating with other devices, which may be collectively referred to as vehicle-to-everything (V2X) communications. Sidelink communications may be based on V2X or other D2D communications, such as proximity services (ProSe), etc. In addition to the UE, sidelink communications may also be sent and received by other transmitting devices and receiving devices such as a roadside unit (RSU) 107, etc. The PC5 interface may be used to exchange sidelink communications, such as in conjunction with Figure 4 Although the examples in Figure 4 The following description of an example time slot structure may provide examples for sidelink communications related to 5G NR, but the concepts described herein may be applicable to other similar areas such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0079] Figure 5 An example 500 of sidelink communication between UE 502, UE 504, and UE 506 is illustrated. Each of UE 502, UE 504, and UE 506 may be configured to communicate with other devices using a D2D connection, such as devices configured to communicate with each other using a D2D communication link 158. Figure 1 The communication may be based on a combination of UE 104 or RSU 107. Figure 4The time slot structure of each aspect described. For example, UE 502 may send a sidelink transmission that can be received by UE 504 or UE 506, and the sidelink transmission includes, for example, a control channel (e.g., PSCCH) and / or a corresponding data channel (e.g., PSCCH). The control channel may include information for decoding the data channel (e.g., sidelink control information (SCI)), which includes reservation information, such as information about time and / or frequency resources reserved for data channel transmission. For example, SCI may indicate the TTI and the number of RBs that will be occupied by the data transmission. SCI can also be used by a receiving device to avoid interference by avoiding transmission on reserved resources. In addition to sidelink reception, UE 502, UE 504, and UE 506 may each be capable of sidelink transmission.

[0080] UE 502 and UE 504 may be configured to communicate using a PC5 RRC link 510 having a PCC 512 and a set of SCCs 514 from UE 502 to UE 504. The set of SCCs 514 may be a set of one or more SCCs. UE 502 and UE 504 may also be configured to communicate using a PC5 RRC link 515 having a PCC 516 and a set of SCCs 518 from UE 504 to UE 502. The set of SCCs 518 may be a set of one or more SCCs. Each of the PC5 RRC links 510, 515 may be a sidelink connection having a PCC and one or more SCCs in a given direction. As shown, UE 502 and UE 504 may be configured to have two separate unidirectional D2D links that allow UE 502 to send sidelink transmissions to UE 504 via PC5 RRC link 510 and allow UE 504 to send sidelink transmissions to UE 502 via PC5 RRC link 515. The resources used for PCC 512 may not overlap with the resources used for PCC 516, thereby allowing simultaneous bidirectional transmissions to occur between UE 502 and UE 504 without interfering with each other.

[0081] Similarly, UE 502 and 506 may be configured to communicate using a PC5 RRC link 520 having a PCC 522 and a SCC set 524 from UE 502 to UE 504. The SCC set 524 may be a set of one or more SCCs. UE 502 and 506 may be configured to communicate using a PC5 RRC link 525 having a PCC 526 and a SCC set 528 from UE 506 to UE 502. The SCC set 528 may be a set of one or more SCCs. Each of the PC5 RRC links 520, 525 may be a side link connection having a PCC and one or more SCCs in a given direction. These transmissions may be unicast, broadcast, or multicast to nearby devices. For example, UE 502 may transmit a broadcast intended to be received by UE 504 and UE 506 within range 501 of UE 502 via PCC 512 and PCC 522. The resources used for PCC 522 may not overlap with the resources used for PCC 526, thereby allowing simultaneous bidirectional transmissions to occur between UE 502 and UE 506 without interfering with each other.

[0082] Figure 6 An example 600 of sidelink communication between UE 602, UE 604, and UE 606 within range 601 is illustrated. Each of UE 602, UE 604, and UE 606 may be similar to UE 502, UE 504, and UE 506, wherein UE 602 and UE 604 may be configured to communicate using a PC5 RRC link 610 having a PCC 612 and a set of SCCs 614 from UE 602 to UE 604. UE 602 and UE 604 may also be configured to communicate using a PC5 RRC link 615 having a PCC 616 and a set of SCCs 618 from UE 604 to UE 602. In other words, UE 602 and 604 may be configured to have two separate unidirectional D2D links, which allow UE 602 to send sidelink transmissions to UE 604 via PC5 RRC link 610 and allow UE 604 to send sidelink transmissions to UE 602 via PC5 RRC link 615. However, the resources used for PCC 612 may overlap with the resources used for PCC 616. In other words, PCC 612 and PCC 616 may share the same CC and / or physical resources. UE 602 and UE 604 may be configured not to schedule simultaneous transmissions using PCC 612 and PCC 616 to minimize the possibility of interference between transmissions. However, since PCC 612 and PCC 616 may share resources (e.g., completely overlapping frequencies), the measurement of PCC 612 may be applied to the configuration of PCC 616, and vice versa.

[0083] Similarly, UE 602 and 606 may be configured to communicate using a PC5 RRC link 620 having a PCC 622 and a set of SCCs 624 from UE 602 to UE 604. UE 602 and 606 may be configured to communicate using a PC5 RRC link 625 having a PCC 626 and a set of SCCs 628 from UE 606 to UE 602. Resources for PCC 622 may also overlap with resources for PCC 626. In other words, PCC 622 and PCC 626 may share the same CC and / or physical resources. Resources for PCC 622 may not overlap with resources for PCC 612.

[0084] Sidelink connections such as Figure 5 PC5 RRC link 510, 515, 520 or 525 or Figure 6 The PC5 RRC links 610, 615, 620, or 625 in the embodiment of the present invention may be associated with carrier aggregation by aggregating a set of carriers into component carriers (CCs) to increase the bandwidth of transmission in one direction. CCs may be intra-band contiguous, intra-band non-contiguous, or inter-band non-contiguous. A sidelink connection may be configured using a PCC configuration that designates one of multiple CCs used for a sidelink connection as a PCC or primary carrier for the sidelink connection, and designates the remaining CCs in the CC as a set of SCCs or alternative carriers for the sidelink connection. A transmitting UE configured to transmit transmissions using a sidelink connection may transmit using an aggregated carrier associated with a PCC. The UE may perform a handover from a PCC identified as CC1 to an SCC identified as CC2 by deactivating CC1 from the PCC of the sidelink connection to the SCC, and then activating CC2 from the SCC of the sidelink connection to the PCC. In some aspects, a sidelink PCC may be configured per UE, per link, or per link per direction.

[0085] In one aspect, the side link PCC may be configured per UE. The coordinating UE may configure one CC as the PCC for all side link links established and / or participated in by the coordinating UE. In order to establish a new side link link to a new UE, the coordinating UE may negotiate with the new UE to ensure that the configured PCC can still act as the PCC for the new link (there is no conflicting side link transmission using the same resources as the PCC for the new link). In some aspects, the coordinating UE may negotiate with the base station or a third UE (e.g., an anchor and / or hub node in a star topology) to ensure that the configured PCC can still act as the PCC for the new link. The coordinating UE may be a transmitting UE (e.g., UE 502 for PC5RRC link 510 and UE 504 for PC5 RRC link 515).

[0086] In another aspect, the sidelink PCC may be configured per link. When a sidelink link is established between a first UE and a second UE, a specific CC may be designated as the primary CC for the link. The base station or anchor UE (i.e., a third UE) may designate the CC as the PCC for the link, or the first UE and the second UE may negotiate the CC as the PCC for the link to establish the link. The designated CC may be a different SL link (e.g., Figure 5 PCC 512 in may not have overlapping resources with PCC 516 and may not have overlapping resources with PCC 522), or may be the same (e.g., Figure 6 The PCC 612 in the UE may have the same resources as the PCC 616), and may be different for unicast links and multicast links. For the purpose of establishing the PCC, the coordination device may treat the multicast link as multiple unicasts. Each UE may have a different set of other CCs in addition to the PCC, for example, Figure 5 UE 502 in the example may have a PCC 512 designated for transmissions to UE 502, while UE 504 may have a different PCC 516 designated for transmissions to UE 504. Each UE may also index its CC in a different manner. For example, UE 502 may index PCC 512 as CC0, while UE 504 may index PCC 512 as CC16. When referring to PCCs, the UEs may be configured to agree on common indexing and / or reference terminology so that they can understand the indication of a common PCC.

[0087] On the other hand, a sidelink PCC may be configured per link per direction. For example, each link may get two sidelink PCCs, one for forward communication and the other for reverse communication. For example, for UE 502, PC5 RRC link 510 may have PCC 512 for forward communication from UE 504 to UE 502, and may be PCC 516 for reverse communication from UE 502 to UE 504. Different PCCs may be distinguished in any suitable manner. In one aspect, the PCC may be configured with a bidirectional forward detection (BFD) reference signal (RS). With bidirectional BFR, the BFD RS from UE 502 to UE 504 may be on PCC 512, and the BFD RS from UE 504 to UE 502 may be on PCC 516. On the other hand, the PCC may carry PSFCH. In other words, PCC 512 may carry the PSFCH from UE 504 to UE 502 , and PCC 516 may carry the PSFCH from UE 502 to UE 504 .

[0088] Although each of the PC5 RRC links 510, 515, 520, and 525 are shown as including a set of SCCs with shared resources, in some aspects, the PC5 RRC link may include a set of SCCs that may have different configurations of resources, thereby allowing the UE to select from multiple potential SCCs with different resources when assigning an SCC in the set of SCCs as a new PCC for a sidelink connection. Although SCCs may be added, removed, activated, and deactivated, special procedures may be defined to appropriately configure a D2D link such as a PC5 RRC link to activate an SCC as a PCC because a sidelink UE may not have a centralized network or base station that can manage and coordinate sidelink transmissions. The PCC configuration may include a series of instructions for deactivating a PCC as an SCC and activating a PCC as an SCC.

[0089] When PCC is configured for sidelink transmission, the sidelink PCC can be centered on the transmitting UE. The sidelink PCC can be defined for each transmitting UE per sidelink, for example. In other words, two independent PC5 RRC connections each on an independent PCC can be established between a pair of UEs. For example, PCC 512 can be defined as a transmission link from UE 502 to UE 504, and PCC 516 can be defined as a transmission link from UE 504 to UE 502. When PCC is defined for each sidelink per transmitting UE, a radio link management system or a radio link failure system can be defined to manage and coordinate the sidelink transmission using CA CC. If the PCC of the sidelink connection is associated with an RLF value (e.g., the number of RLC retransmissions, a timer indicating the time that has elapsed since the sidelink RRC reconfiguration for the sidelink connection was sent, the number of continuous hybrid automatic repeat requests (HARQ) discontinuous transmissions (DTX) for the destination of the sidelink connection) that meets or exceeds the RLF limit threshold, the UE can detect that the PCC RLF has occurred. A UE that detects that a PCC RLF has occurred may deactivate the PCC of the sidelink connection and activate an SCC in the SCC set that is capable of maintaining the sidelink connection (eg, the SCC having a measured RSRP value that meets or exceeds an RSRP threshold).

[0090] The first UE may be configured to establish a sidelink connection with at least one second UE via a first PCC or at least one second PCC. The first PCC and the first set of SCCs may be associated with a first transmission of the first UE. At least one second PCC and at least one second set of SCCs may be associated with a second transmission of at least one second UE. The sidelink connection with at least one second UE may be associated with carrier aggregation. The first UE may be further configured to detect at least one of the following: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) at least one SCC in the first set of SCCs or at least one SCC in at least one second set of SCCs is capable of maintaining the sidelink connection. The first UE may be further configured to send a first indication of at least one of the following: (i) the sidelink connection is associated with an RLF value within the RLF threshold of the RLF limit, or (ii) at least one SCC in the first set of SCCs or at least one SCC in at least one second set of SCCs is capable of maintaining the sidelink connection. The first UE may be further configured to receive a second indication of switching of the sidelink connection from the first PCC to a first SCC in the first set of SCCs or from at least one second PCC to at least a second SCC in at least one second set of SCCs based on the first indication.

[0091] The second UE may be configured to establish a sidelink connection with at least one first UE via a first PCC or a second PCC. At least one first PCC and at least one first set of SCCs may be associated with a first transmission of at least one first UE. A second PCC and a second set of SCCs may be associated with a second transmission of the second UE. The sidelink connection with at least one first UE may be associated with carrier aggregation. The second UE may be further configured to receive a first indication of at least one of: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) at least one SCC in at least one first set of SCCs or at least one SCC in a second set of SCCs is able to maintain the sidelink connection. The second UE may be further configured to: switch the sidelink connection from at least one first PCC to at least a first SCC in a first set of SCCs, or from a second PCC to a second SCC in a second set of SCCs based on the first indication. The second UE may be further configured to send a second indication of switching of the sidelink connection from at least one first PCC to at least a first SCC in a first set of SCCs or from a second PCC to a second SCC in a second set of SCCs.

[0092] Random Access Channel (RACH) measurements may be performed by the UE in each direction on the PCC. Figure 5, UE 502 may measure RACH and / or RSRP on PCC 516 and PCC 526, UE 504 may measure RACH and / or RSRP on PCC 512, and UE 506 may measure RACH and / or RSRP on PCC 522. Similarly, in Figure 6 In the example, UE 602 may measure RACH and / or RSRP on PCC 616 and PCC 626, UE 604 may measure RACH and / or RSRP on PCC 612, and UE 606 may measure RACH and / or RSRP on PCC 622. The measurement report may be returned to the sending UE via the side link. RLM and / or RLF may be declared on the PCC in each direction. The UE may announce its PCC information in the synchronization signal block (SSB) system information block (SIB). For example, in Figure 5 , UE 502 may announce the PCC information of PCC 512 in the SSB SIB as a notification to UE 504, UE 502 may announce the PCC information of PCC 522 in the SSB SIB as a notification to UE 506, UE 504 may announce the PCC information of PCC 516 in the SSB SIB as a notification to UE 502, and UE 506 may announce the PCC information of PCC 526 in the SSB SIB as a notification to UE 502. Similarly, in Figure 6 In the present invention, UE 602 may announce the PCC information of PCC 612 in the SSB SIB as a notification to UE 604, UE 602 may announce the PCC information of PCC 622 in the SSB SIB as a notification to UE 606, UE 604 may announce the PCC information of PCC 616 in the SSB SIB as a notification to UE 602, and UE 606 may announce the PCC information of PCC 626 in the SSB SIB as a notification to UE 602.

[0093] The UE may be configured to update the PCC configuration of the sidelink link by sending an update to the PCC configuration to another UE participating in the sidelink link. For example, UE 502 may be configured to send an update to the PCC configuration for PC5 RRC link 510 to UE 504 to designate an SCC in SCC set 514 as a new PCC for PC5 RRC link 510. In response, UE 504 may switch the sidelink connection from PCC 512 to the designated SCC of SCC set 514 in the update, or may fail to switch the sidelink connection from PCC 512 to the designated SCC of SCC set 514 in the update. UE 504 may then send an indication of a successful handover to UE 502, or may send an indication of an RLF of a handover sidelink connection failure. In another aspect, UE 502 may be configured to send an update of the PCC configuration for PC5 RRC link 515 to UE 504 to designate an SCC in SCC set 518 as a new PCC for PC5 RRC link 515. In response, UE 504 may switch the sidelink connection from PCC 516 to the designated SCC of SCC set 518 in the update, or may fail to switch the sidelink connection from PCC 516 to the designated SCC of SCC set 518 in the update. UE 504 may then send an indication of a successful handover to UE 502, or may send an indication of an RLF of a handover sidelink connection failure. Such updates and handovers may also be configured to be sent in the opposite direction. In some aspects, the receiving UE may not be authorized to initiate a handover, but may be authorized to send an update as a request to the sending UE to perform a handover.

[0094] Figure 7 A connection flow diagram 700 is illustrated, which illustrates a UE 702 and a UE 704, such as Figure 5 UE 502 and UE 504 or Figure 6 The radio link management system between UE 602 and UE 604 in FIG. UE 702 and 704 may be configured to exchange side link transmissions with each other using a D2D communication link 706 via a configured PCC. Figure 5Among them, the UE 502 can use the PC5 RRC link 510 to exchange sidelink transmissions with the UE 504. The PC5 RRC link has a PCC 512 for sending sidelink transmissions from the UE 502 to the UE 504 and a PCC 516 for sending sidelink transmissions from the UE 504 to the UE 502. The CC can be configured by the UE502 and the UE 504 in any suitable manner, such as per link per direction. The UE 702 can be configured to send a notification associated with the PCC related to the UE702, and the UE 704 can be configured to send a notification associated with the PCC related to the UE 704. The notification can be sent in a set of synchronization signal blocks (SSBs) and system information blocks (SIBs) in either direction.

[0095] At 708, the UE 702 can detect that a PCC RLF is about to occur by detecting whether the sidelink connection is associated with an RLF value within the RLF threshold restricted by the RLF. If the sidelink connection is associated with an RLF value that meets or exceeds the RLF restriction, the UE 702 can detect that a PCC RLF has occurred. The RLF value can be, for example, the number of RLC retransmissions, a timer indicating the time elapsed since the sidelink RRC reconfiguration for the sidelink connection was sent, or the number of consecutive hybrid automatic repeat request (HARQ) discontinuous transmissions (DTX) for the destination of the sidelink connection. The UE 702 can be configured to detect that an RLF is about to occur on the PCC from the UE 702 to the UE 704 or on the PCC from the UE 704 to the UE 702.

[0096] For example, the UE 702 can detect that the PCC is approaching the maximum number of RLC retransmissions (e.g., Nmax) by detecting that the number of RLC retransmissions is within a threshold number of the maximum number of RLC retransmissions (e.g., within 5 retransmissions or within 10 retransmissions). In one aspect, the UE 702 can be configured to detect the nth percentile of the maximum configured RLC retransmission value, where n can be configured by RRC (e.g., 90% of Nmax). In another implementation, the UE 702 can have a defined threshold Nmax1 that triggers an upcoming PCC RLF condition where a PCC RLF is about to occur, where Nmax1 < Nmax, and Nmax is the maximum number of RLC transmissions.

[0097] In another embodiment, UE 702 may detect that the PCC is approaching the expiration of the sidelink T400 timer (e.g., T400_Max). For example, UE 702 may start the timer after having transmitted or received a transmission of a sidelink RRC reconfiguration for sidelink transmission, may have an expiration time corresponding to the RRC reconfiguration, and may detect that the timer is within a threshold number of the expiration of the sidelink T400 timer (e.g., within 5 seconds or within 10 seconds). UE 702 may be configured to detect the nth percentile of the maximum configured value of the T400 time (e.g., 90% of T400_Max), where n may be configured by RRC. When the timer reaches such a threshold without receiving / sending an indicator of success or failure of an RRC reconfiguration for sidelink transmission, UE 702 may trigger an impending PCC RLF condition.

[0098] In another embodiment, UE 702 may detect that the PCC is approaching the maximum number of consecutive HARQ DTXs for a particular destination (e.g., the H_Dtx_Max value) by detecting that the number of consecutive HARQ DTXs is within a threshold number of the maximum number (e.g., within 5 consecutive HARQ DTXs of the H_Dtx_Max value). UE 702 may be configured to detect the nth percentile of H_Dtx_Max (e.g., 90% of H_Dtx_Max), where n may be configured by RRC. In another embodiment, UE 702 may have a defined threshold H_Dtx_Max1 that triggers an impending PCC RLF condition where the PCC RLF is impending, where H_Dtx_Max1 < H_Dtx_Max, and H_Dtx_Max is the maximum number of consecutive HARQ DTXs.

[0099] UE 702 may be configured to send an indication 710 of the impending PCC RLF to UE704, for example, by sending a measured RLF value that is approaching the RLF limit, by sending an indication that the RLF value of the PCC may be approaching the RLF limit, by sending an indication that the RLF value has reached the RLF threshold of the RLF limit, or by sending an update of the PCC configuration for the D2D communication link 706 for the SCC set used for the D2D communication link 706. The update may include selecting a suitable or advantageous SCC from the SCC set to designate as the new PCC.

[0100] In some aspects, if there are multiple D2D communication links between a pair of UEs on the same CC and / or physical resource, an impending RLF detected on one PCC may trigger an impending RLF detected on another PCC. For example, in Figure 6In the case where PC5 RRC link 610 has PCC 612 using the same CC as PC5 RRC link 615, an impending RLF detected on PCC 612 may trigger an impending RLF detected on PCC 616, or an impending RLF detected on PCC 616 may trigger an impending RLF detected on PCC 612. In other words, in Figure 6 In the embodiment, between UE 602 and UE 604, when RLF is detected on PC5 RRC link 610 and / or PC5 RRC link 615, based on channel reciprocity, measurements associated with relay reselection and / or PCC change procedures may be performed on one of PC5 RRC link 610 or PC5 RRC link 615, and the measurements may be shared to the other PC5 RRC link. Such measurements may be applied to any suitable RLF value, such as the number of RLC retransmissions, the time since the transmission of a sidelink RRC reconfiguration for a sidelink connection, or the number of consecutive HARQ DTXs for a destination of a sidelink connection. If the sidelink links share resources, one or more measurements of one sidelink link between UE 702 and UE 704 may be correlated or synchronized with one or more measurements of another sidelink link between UE 702 and UE 704 in the opposite direction. If the RLF value is the time since the transmission of a sidelink RRC reconfiguration for a sidelink connection, the timers for each UE may operate in a correlated or synchronized manner relative to each other. For example, when a timer in one direction has started, a timer in the opposite direction may be activated and incremented.

[0101] In some aspects, UE 702 may be configured to send an indication 710 of an upcoming PCC RLF to UE 704 for both PCCs of a D2D communication link between UE 702 and UE 704 rather than just one PCC, or UE 704 may interpret an indication 710 of an upcoming PCC RLF to the UE as two upcoming PCC RLFs for one PCC of the D2D communication link, with the two upcoming PCC RLFs being used for each PCC that is related to each other (e.g., the PCCs share the same resources).

[0102] At 712, in response, UE 704 may be configured to switch the sidelink connection from the PCC to the SCC. Figure 5In response to UE 504 receiving from UE 502 an indication that PCC 512 has an RLF value that has reached an RLF threshold for an RLF limit, UE 504 may switch PC5 RRC link 510 from PCC 512 to an SCC in SCC set 514. On the other hand, in response to UE 504 receiving from UE 502 an indication that PCC 516 has an RLF value that has reached an RLF threshold for an RLF limit, UE 504 may switch PC5 RRC link 515 from PCC 516 to an SCC in SCC set 518.

[0103] UE 704 may send an indication 714 of a switch from the PCC to the SCC to UE 702. The triggering from UE 704 to UE 702 to activate the pre-configured SCC as the PCC may be accomplished using a MAC-CE or SCI2 level indication. In other words, the indication 714 may be sent in a MAC-CE transmission or an SCI transmission. The indication 714 may include an update of the PCC configuration for the D2D communication link 706 for the set of SCCs used for the D2D communication link 706. The update may include a selection of an SCC in the set of SCCs that the UE 704 has designated as the new PCC at 712. At 716, in response to receiving the indication 714 of a switch from the PCC to the SCC, the UE 702 may switch the sidelink connection from the PCC to the SCC. For example, at Figure 5 In the embodiment, in response to UE 502 receiving an indication from UE 704 that PC5 RRC link 510 has been switched from PCC 512 to an SCC in SCC set 514, UE 502 may switch from PCC 512 to an SCC in SCC set 514. On the other hand, in response to UE 502 receiving an indication from UE 704 that PC5 RRC link 515 has been switched from PCC 516 to an SCC in SCC set 518, UE 502 may switch from PCC 516 to an SCC in SCC set 518.

[0104] UE 702 may send an indication 718 of the success or failure of its handover from the PCC to the SCC to UE 704. If a PCC change is not possible, UE 702 may declare RLF of the PCC. The PCC may carry joint control information (e.g., SCI2 for both the PCC and the SCC), and thus, the sidelink connection may not survive without the PCC. Subsequently, UE 704 may determine that the sidelink connection has failed, thereby indicating that a new sidelink connection is to be initialized before UE 702 and UE 704 can communicate with each other using the D2D communication link.

[0105] In response to UE 704 receiving an indication of success 718 from UE 702, UE 704 may determine that the sidelink switch from the PCC to the SCC has been successful, and UE 702 and UE 704 may exchange sidelink transmissions with each other using a D2D communication link 720 via the newly configured PCC.

[0106] Figure 8 A connection flow diagram 800 is illustrated, which illustrates a UE 802 and a UE 804 such as Figure 5 UE 502 and UE 504 or Figure 6 802 and 804 may be configured to exchange sidelink transmissions with each other using a D2D communication link 806 via a configured PCC. Figure 5 5, UE 502 may exchange sidelink transmissions with UE 504 using PC5 RRC link 510 having PCC 512 for transmitting sidelink transmissions from UE 502 to UE 504 and PCC 516 for transmitting sidelink transmissions from UE 504 to UE 502. The CCs may be configured by UE 502 and UE 504 in any suitable manner, such as per link per direction. UE 802 may be configured to send a notification that the PCC is associated with UE 802, and UE 804 may be configured to send a notification that the PCC is associated with UE 804. The notification may be sent in a set of synchronization signal blocks (SSBs) system information blocks (SIBs).

[0107] At 807, UE 802 may detect that a PCC RLF is about to occur by detecting whether the side link connection is associated with an RLF value within an RLF threshold of an RLF limit. If the side link connection is associated with an RLF value that meets or exceeds the RLF limit, UE 802 may detect that a PCC RLF has occurred. The RLF value may be, for example, the number of RLC retransmissions, a timer indicating the time that has elapsed since a side link RRC reconfiguration for the side link connection was sent, or the number of consecutive hybrid automatic repeat request (HARQ) discontinuous transmissions (DTX) for the destination of the side link connection. UE 802 may be configured to detect that an RLF is about to occur on a PCC from UE 802 to UE 804 or on a PCC from UE 804 to UE 802.

[0108] For example, the UE 802 can detect that the PCC is approaching the maximum number of RLC retransmissions by detecting that the number of RLC retransmissions is within a threshold number of the maximum number of RLC retransmissions (e.g., within 5 retransmissions or within 10 retransmissions). In one aspect, the UE 802 can be configured to detect the nth percentile of the maximum configured RLC retransmission value, where n can be configured by RRC (e.g., 90% of Nmax). In another embodiment, the UE 802 can have a defined threshold Nmax1 that triggers an impending PCC RLF condition indicating that the PCC RLF is about to occur, where Nmax1 < Nmax, and Nmax is the maximum number of RLC transmissions.

[0109] In another embodiment, the UE 802 can detect that the PCC is approaching the expiration of the sidelink T400 timer (e.g., T400_Max). For example, the UE 802 can start the timer after transmitting or receiving a transmission of a sidelink RRC reconfiguration for sidelink transmission, can have an expiration time corresponding to the RRC reconfiguration, and can detect that the timer is within a threshold of the expiration of the sidelink T400 timer (e.g., within 5 seconds or within 10 seconds). The UE 802 can be configured to detect the nth percentile of the maximum configured value of the T400 time (e.g., 90% of T400_Max), where n can be configured by RRC. When the timer reaches such a threshold without receiving / sending an indicator of success or failure of the RRC reconfiguration for sidelink transmission, the UE 802 can trigger an impending PCC RLF condition.

[0110] In another embodiment, the UE 802 can detect that the PCC is approaching the maximum number of consecutive HARQ DTXs for a specific destination by detecting that the number of consecutive HARQ DTXs is within a threshold number of the maximum number (e.g., within 5 consecutive HARQ DTXs of the H_Dtx_Max value). The UE 802 can be configured to detect the nth percentile of H_Dtx_Max (e.g., 90% of H_Dtx_Max), where n can be configured by RRC. In another embodiment, the UE 802 can have a defined threshold H_Dtx_Max1 that triggers an impending PCC RLF condition indicating that the PCC RLF is about to occur, where H_Dtx_Max1 < H_Dtx_Max, and H_Dtx_Max is the maximum number of consecutive HARQ DTXs.

[0111] In some aspects, if there are multiple D2D communication links between a pair of UEs on the same CC and / or physical resources, an impending RLF detected on one PCC may trigger an impending RLF detected on another PCC. Figure 6 In the case where PC5 RRC link 610 has PCC 612 using the same CC as PC5 RRC link 615, an impending RLF detected on PCC 612 may trigger an impending RLF detected on PCC 616, or an impending RLF detected on PCC 616 may trigger an impending RLF detected on PCC 612. In other words, in Figure 6 In the embodiment, between UE 602 and UE 604, when RLF is detected on PC5 RRC link 610 and / or PC5 RRC link 615, based on channel reciprocity, measurements associated with relay reselection and / or PCC change procedures may be performed on one of PC5 RRC link 610 or PC5 RRC link 615, and the measurements may be shared to the other PC5 RRC link. Such measurements may be applied to any suitable RLF value, such as the number of RLC retransmissions, the time since the transmission of a sidelink RRC reconfiguration for a sidelink connection, or the number of consecutive HARQ DTXs for a destination of a sidelink connection. If the sidelink links share resources, one or more measurements of one sidelink link between UE 802 and UE 804 may be correlated or synchronized with one or more measurements of another sidelink link between UE 802 and UE 804 in the opposite direction. If the RLF value is the time since the transmission of a sidelink RRC reconfiguration for a sidelink connection, the timers for each UE may operate in a correlated or synchronized manner relative to each other. For example, when a timer in one direction has started, a timer in the opposite direction may be activated and incremented.

[0112] At 808, UE 802 may detect that the SCC is able to maintain the sidelink connection by detecting whether a reference signal received quality (RSRP) value of the SCC meets or exceeds a threshold. The threshold may be configured by RRC. UE 802 may use a PC5-RRC reconfiguration message to preemptively provide a PCC configuration for the selected SCC as the PCC, but keep the selected SCC inactive. For example, in Figure 58, the UE 802 may measure the RSRP values ​​of the SCC set 514 to determine whether they meet or exceed a threshold. In response to determining that one or more RSRP values ​​of the SCC 514 meet or exceed the threshold, the UE 802 may send an indication 810 to the UE 804 that a subset of the SCC set 514 is capable of maintaining a sidelink connection. In some aspects, the indication 810 may include a PCC configuration for the selected SCC. In some aspects, the UE 802 may monitor multiple SCCs and may select an SCC for a PCC change based on channel quality (e.g., selecting an SCC with a highest measured RSRP value).

[0113] In another aspect, the UE 802 may measure the RSRP values ​​of the SCC set 518 to determine whether they meet or exceed a threshold. In response to determining that one or more RSRP values ​​of the SCC set 518 meet or exceed a threshold, the UE 802 may send an indication 810 to the UE 804 that a subset of the SCC set 518 is capable of maintaining a sidelink connection. In some aspects, the indication 810 may include an update of a PCC configuration for the D2D communication link 806 for the SCC set used for the D2D communication link 806. The update may include selecting a suitable, advantageous, and / or selected SCC from the SCC set to designate as a new PCC. In some aspects, the UE 802 may monitor multiple SCCs and may select an SCC for a PCC change based on channel quality (e.g., selecting an SCC with a highest measured RSRP value).

[0114] At 812, UE 804 may switch the sidelink connection from the PCC to the SCC. In some aspects, UE 804 may respond to a received indication such as Figure 7 804 may switch the sidelink connection from the PCC to the SCC in response to detecting a triggering condition, such as by detecting that one or more RSRP values ​​of the PCC meet or fall below an RSRP threshold. In response to detecting that one or more RSRP values ​​of the PCC meet or fall below an RSRP threshold, the UE 804 may switch the sidelink connection from the PCC to the SCC by initiating a PCC change procedure at 812. For example, in Figure 5In response to UE 504 detecting that one or more RSRP values ​​of PCC 512 meet or fall below the RSRP threshold, UE 504 may switch the sidelink connection from PCC 512 to an SCC in SCC set 514. An update to the PCC configuration for SCC set 514 may have been provided by UE 504 to UE 502 as an indication 810 that the SCC is capable of maintaining the sidelink connection. On the other hand, in response to UE 504 detecting that one or more RSRP values ​​of PCC 516 meet or fall below the RSRP threshold, UE 504 may switch the sidelink connection from PCC 516 to an SCC in SCC set 518. The PCC configuration for PCC 516 may have been provided by UE 504 to UE 502 as an indication 810 that the SCC is capable of maintaining the sidelink connection.

[0115] UE 804 may send an indication 814 of a switch from the PCC to the SCC to UE 802. The triggering from UE 804 to UE 802 to activate the pre-configured SCC as the PCC may be accomplished using a MAC-CE or SCI2 level indication. In other words, the indication 814 may be sent in a MAC-CE transmission or an SCI transmission. The indication 814 may include an update of the PCC configuration for the D2D communication link 806 for the SCC set for the D2D communication link 806. The update may include a selection of an SCC in the SCC set that the UE 804 has designated as the new PCC at 812.

[0116] At 816, in response to receiving the indication 814 of switching from the PCC to the SCC, the UE 802 may switch the sidelink connection from the PCC to the SCC. Figure 5 In the embodiment, in response to UE 502 receiving an indication from UE 804 that PC5 RRC link 510 has been switched from PCC 512 to an SCC in SCC set 514, UE 502 may switch from PCC 512 to an SCC in SCC set 514. On the other hand, in response to UE 502 receiving an indication from UE 804 that PC5 RRC link 515 has been switched from PCC 516 to an SCC in SCC set 518, UE 502 may switch from PCC 516 to an SCC in SCC set 518.

[0117] UE 802 may send an indication 818 of the success or failure of its handover from the PCC to the SCC to UE 804. If a PCC change is not possible, UE 802 may declare RLF of the PCC. The PCC may carry joint control information (e.g., SCI2 for both the PCC and the SCC), and thus, the sidelink connection may not survive without the PCC. Subsequently, UE 804 may determine that the sidelink connection has failed, thereby indicating that a new sidelink connection is to be initialized before UE 802 and UE 804 can communicate with each other using the D2D communication link.

[0118] In response to UE 804 receiving an indication of success 818 from UE 802, UE 804 may determine that the sidelink switch from the PCC to the SCC has been successful, and UE 802 and UE 804 may exchange sidelink transmissions with each other using a D2D communication link 820 via the newly configured PCC.

[0119] Fig. 9 900 is a flowchart of a method of wireless communication. The method may be performed by a UE (e.g., UE 104, UE 502, UE 504, UE 506, UE 602, UE 604, UE 606, UE 702, UE 704, UE 802, UE 804; wireless communication device 310, wireless communication device 350; apparatus 1104). At 902, the UE may establish a sidelink connection with at least one second UE via a first PCC or at least one second PCC. A first set of a first PCC and an SCC may be associated with a first transmission of the first UE. At least one second set of at least one second PCC and an SCC may be associated with a second transmission of at least one second UE. The sidelink connection with at least one second UE may be associated with carrier aggregation. For example, 902 may be performed by Figure 5 514. The UE 502 in FIG. 9 may establish a PC5 RRC link 510 with the UE 504 via the PCC 512, or may establish a PC5 RRC link 515 with the UE 504 via the PCC 516. The PCC 512 and the SCC set 514 may be associated with transmissions transmitted from the UE 502 to the UE 504, because the transmissions may be transmitted from the UE 504 to the UE 502 using the PCC 512 or the SCC set 514. The PCC 516 and the SCC set 518 may be associated with transmissions from the UE 504 to the UE 502, because the transmissions may be transmitted to the UE 502 via the PCC 516 or the SCC set 518. The PC5 RRC link 510 may be associated with carrier aggregation of the PCC 512 and the SCC set 514. The RRC link 515 may be associated with carrier aggregation of the PCC 516 and the SCC set 518. In addition, 902 may be associated with Fig.11 Component 198 in is executed.

[0120] At 904, the UE may detect at least one of: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) at least one SCC in the first set of SCCs or at least one SCC in the at least one second set of SCCs is capable of maintaining the sidelink connection. For example, 904 may be performed by Figure 5 514. The UE 502 may perform a method for determining whether the PCC 512 of the PC5 RRC link 510 is associated with an RLF value within an RLF threshold of an RLF limit, such as the number of RLC retransmissions, a timer indicating the time that has elapsed since a sidelink RRC reconfiguration of the sidelink connection was sent, or the number of consecutive HARQ DTXs for a destination of the sidelink connection. The UE 502 may also detect that the PCC 516 of the PC5 RRC link 515 is associated with an RLF value within an RLF threshold of an RLF limit. The UE 502 may also determine whether at least one SCC in the SCC set 514 is capable of maintaining the PC5 RRC link 510. The UE 502 may also determine whether at least one SCC in the SCC set 518 is capable of maintaining the PC5 RRC link 515. In addition, 904 may be performed by Fig.11 Component 198 in is executed.

[0121] At 906, the UE may send a first indication of at least one of: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) at least one SCC in the first set of SCCs or at least one SCC in at least one second set of SCCs is able to maintain the sidelink connection. For example, 906 may be Figure 5 502 in the embodiment of the present invention may send an indication that the PCC 512 of the PC5 RRC link 510 is associated with an RLF value within an RLF threshold of the RLF limit. The UE 502 may also send an indication that the PCC 516 of the PC5 RRC link 515 is associated with an RLF value within the RLF threshold of the RLF limit. The UE 502 may also send an indication that a subset of the SCCs in the SCC set 514 is capable of maintaining the PC5 RRC link 510. The UE 502 may also send an indication that a subset of the SCCs in the SCC set 518 is capable of maintaining the PC5 RRC link 515. In addition, 906 may be performed by Fig.11 Component 198 in is executed.

[0122] Finally, at 908, the UE may receive a second indication of switching of the sidelink connection from the first PCC to a first SCC in the first set of SCCs or from at least one second PCC to at least a second SCC in at least one second set of SCCs based on the first indication. For example, 908 may be Figure 5514. The UE 502 may receive an indication of switching the PC5 RRC link 510 from the PCC 512 to the SCC in the SCC set 514 based on the first indication. The UE 502 may also receive an indication of switching the PC5 RRC link 515 from the PCC 516 to the SCC in the SCC set 518 based on the first indication. In addition, 908 may be performed by Fig.11 Component 198 in is executed.

[0123] Fig.10 1000 is a flowchart of a method of wireless communication. The method may be performed by a UE (e.g., UE 104, UE 502, UE 504, UE 506, UE 602, UE 604, UE 606, UE 702, UE 704, UE 802, UE 804; wireless communication device 310, wireless communication device 350; apparatus 1104). At 1002, the UE may establish a sidelink connection with at least one first UE via at least one first PCC or a second PCC. At least one first set of at least one first PCC and SCC may be associated with a first transmission of the at least one first UE. A second set of a second PCC and SCC may be associated with a second transmission of a second UE. The sidelink connection with the at least one first UE may be associated with carrier aggregation. For example, 1002 may be performed by Figure 5 514. The UE 504 in FIG. 100 may establish a PC5 RRC link 510 with the UE 502 via the PCC 512. The UE 504 may establish a PC5 RRC link 515 with the UE 502 via the PCC 516. The PCC 512 and the SCC set 514 may be associated with transmissions transmitted from the UE 502 to the UE 504, because the transmissions may be transmitted from the UE 504 to the UE 502 using the PCC 512 or the SCC set 514. The PCC 516 and the SCC set 518 may be associated with transmissions from the UE 504 to the UE 502, because the transmissions may be transmitted to the UE 502 via the PCC 516 or the SCC set 518. The PC5 RRC link 510 may be associated with carrier aggregation of the PCC 512 and the SCC set 514. The RRC link 515 may be associated with carrier aggregation of the PCC 516 and the SCC set 518. In addition, the UE 1002 may be associated with the PCC 512 and the SCC set 514. Fig.11 Component 199 in is executed.

[0124] At 1004, the UE may receive a first indication of at least one of: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) at least one SCC in at least one first set of SCCs or at least one SCC in the second set of SCCs is able to maintain the sidelink connection. For example, 1004 may be Figure 5502 may receive an indication that a PCC 512 of a PC5 RRC link 510 is associated with an RLF value within an RLF threshold of an RLF limit, such as a number of RLC retransmissions, a timer indicating a time that has elapsed since a sidelink RRC reconfiguration of a sidelink connection was sent, or a number of consecutive HARQ DTXs for a destination of the sidelink connection. The UE 504 may also receive an indication that a PCC 516 of a PC5 RRC link 515 is associated with an RLF value within an RLF threshold of an RLF limit. The UE 504 may also receive an indication that a subset of the SCC set 514 is capable of maintaining the PC5 RRC link 510. The UE 502 may also receive an indication that a subset of the SCC set 518 is capable of maintaining the PC5 RRC link 515. In addition, 1004 may be Fig.11 Component 199 in is executed.

[0125] At 1006, the UE may switch the sidelink connection from at least one first PCC to at least a first SCC in at least one first set of SCCs, or from a second PCC to a second set of SCCs based on the first indication. For example, 1006 may be performed by UE 504, which may switch PC5 RRC link 510 from PCC 512 to an SCC in SCC set 514 based on the first indication. UE 504 may switch PC5 RRC link 515 from PCC 516 to an SCC in SCC set 518 based on the first indication. In addition, 1006 may be performed by Fig.11 Component 199 in is executed.

[0126] Finally, at 1008, the UE may send a second indication of switching of the sidelink connection from at least one first PCC to at least a first SCC in the first set of SCCs or from a second PCC to a second SCC in the second set of SCCs. For example, 1008 may be Figure 5 1008 may be performed by UE 504 in the embodiment, which may send a second indication of switching of PC5 RRC link 510 from PCC 512 to an SCC in SCC set 514. UE 504 may also send a second indication of switching of PC5 RRC link 515 from PCC 516 to an SCC in SCC set 518. In addition, 1008 may be performed by UE 504 in the embodiment, which may send a second indication of switching of PC5 RRC link 510 from PCC 512 to an SCC in SCC set 514. Fig.11 Component 199 in is executed.

[0127] Fig.111100 is a diagram illustrating an example of a hardware implementation for an apparatus 1104. The apparatus 1104 may be a UE, a component of a UE, or may implement UE functionality. In some aspects, the apparatus 1104 may include a cellular baseband processor 1124 (also referred to as a modem) coupled to one or more transceivers 1122 (e.g., a cellular RF transceiver). The cellular baseband processor 1124 may include on-chip memory 1124'. In some aspects, the apparatus 1104 may also include one or more subscriber identity module (SIM) cards 1120 and an application processor 1106 coupled to a secure digital (SD) card 1108 and a screen 1110. The application processor 1106 may include on-chip memory 1106'. In some aspects, the device 1104 may also include a Bluetooth module 1112, a WLAN module 1114, an SPS module 1116 (e.g., a GNSS module), one or more sensor modules 1118 (e.g., an atmospheric pressure sensor / altimeter; a motion sensor such as an inertial management 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 1126, a power source 1130, and / or a camera 1132. The Bluetooth module 1112, the WLAN module 1114, and the SPS module 1116 may include an on-chip transceiver (TR X ) (or in some cases, only the receiver (R X)). The Bluetooth module 1112, the WLAN module 1114, and the SPS module 1116 may include their own dedicated antennas and / or communicate using antennas 1180. The cellular baseband processor 1124 communicates with the UE 104 and / or with the RU associated with the network entity 1102 via one or more antennas 1180 through the transceiver 1122. The cellular baseband processor 1124 and the application processor 1106 may each include a computer-readable medium / memory 1124', 1106', respectively. The additional memory module 1126 may also be considered as a computer-readable medium / memory. Each computer-readable medium / memory 1124', 1106', 1126 may be non-transitory. The cellular baseband processor 1124 and the application processor 1106 are each responsible for general processing, including executing software stored on a computer-readable medium / memory. When executed by the cellular baseband processor 1124 / application processor 1106, the software enables the cellular baseband processor 1124 / application processor 1106 to perform the various functions described above. The computer-readable medium / memory may also be used to store data manipulated by the cellular baseband processor 1124 / application processor 1106 when executing software. The cellular baseband processor 1124 / application processor 1106 may be a component of the wireless communication device 350 and may include the memory 360 and / or at least one of the Tx processor 368, the Rx processor 356, and the controller / processor 359. In one configuration, the device 1104 may be a processor chip (modem and / or application) and only include the cellular baseband processor 1124 and / or the application processor 1106, and in another configuration, the device 1104 may be the entire UE (e.g., see Figure 3 The wireless communication device 350) includes an additional module of the device 1104.

[0128] As discussed above, component 198 is configured to establish a sidelink connection with a first UE via a first PCC or at least one second PCC. The first PCC and the first SCC may be associated with a first transmission of the first UE. At least one second PCC and at least one second SCC may be associated with a second transmission of the second UE. The sidelink connection with the first UE may be associated with carrier aggregation. Component 198 may also be configured to detect at least one of the following: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) the first SCC or at least one second SCC is capable of maintaining the sidelink connection. Component 198 may also be configured to send a first indication of at least one of the following: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) the first SCC or at least one second SCC is capable of maintaining the sidelink connection. Component 198 may also be configured to receive a second indication of a switching of the sidelink connection from the first PCC to the first SCC or from at least one second PCC to at least one second SCC based on the first indication. Component 198 may be within the cellular baseband processor 1124, the application processor 1106, or both the cellular baseband processor 1124 and the application processor 1106. Component 198 may be one or more hardware components that are specifically configured to perform the process / algorithm, implemented by one or more processors configured to perform the process / algorithm, stored in a computer-readable medium for implementation by one or more processors, or some combination thereof. As shown, the device 1104 may include a variety of components configured for various functions. In one configuration, the device 1104, and specifically the cellular baseband processor 1124 and / or the application processor 1106, includes a component for establishing a sidelink connection with the first UE via a first PCC or at least one second PCC. The device 1104 may also include a component for detecting at least one of the following: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) the first SCC or at least one second SCC is able to maintain a sidelink connection. The apparatus 1104 may also include means for sending a first indication of at least one of: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) the first SCC or at least one second SCC is capable of maintaining the sidelink connection. The apparatus 1104 may also include means for receiving a second indication of a switching of the sidelink connection from the first PCC to the first SCC or from the at least one second PCC to the at least one second SCC based on the first indication. The apparatus 1104 may also include means for sending a first notification that the first PCC is associated with the first UE. The apparatus 1104 may also include means for receiving a second notification that the at least one second PCC is associated with the at least one second UE.The apparatus 1104 may also include: a component for sending at least a first transmission to at least one second UE via the first PCC. The apparatus 1104 may also include: a component for receiving at least a second transmission from at least one second UE via the at least one second PCC. The apparatus 1104 may also include: a component for detecting that the first SCC or at least one second SCC is capable of maintaining a sidelink connection in response to detecting that at least one RSRP value of the first SCC or at least one second SCC is greater than or equal to an RSRP threshold. The apparatus 1104 may also include: a component for sending a PCC configuration for the first SCC or at least one second SCC in response to detecting that the first SCC or at least one second SCC is capable of maintaining a sidelink connection. The apparatus 1104 may also include: a component for sending a PCC configuration for the first SCC in response to detecting that at least one RSRP value of the first SCC is greater than a first set of detected RSRP values ​​of other SCCs associated with the first transmission of the first UE. The device 1104 may also include: a component for sending a PCC configuration for at least one second SCC in response to detecting that at least one RSRP value of at least one second SCC is greater than a second set of detected RSRP values ​​of other SCCs associated with a second transmission of at least one second UE. The device 1104 may also include: a component for sending a third indication for switching the sidelink connection from the first PCC to the first SCC or from the at least one second PCC to the at least one second SCC in response to detecting that at least one RSRP value of the first PCC or the at least one second PCC is less than or equal to the RSRP threshold. The device 1104 may also include: a component for sending a third indication of RLF in response to a failure to switch the sidelink connection from the first PCC to the first SCC or from the at least one second PCC to the at least one second SCC. The device 1104 may also include: a component for activating a first timer for a third transmission of a first sidelink RRC reconfiguration of a first sidelink connection with at least one second UE via the first PCC after activating a second timer for a fourth transmission of a second sidelink RRC reconfiguration of a second sidelink connection with at least one second UE via the at least one second PCC. The means may be a component 198 of the device 1104 configured to perform the functions recited by the means. As described above, the device 1104 may include a Tx processor 368, an Rx processor 356, and a controller / processor 359. Thus, in one configuration, the means may be a Tx processor 368, an Rx processor 356, and a controller / processor 359 configured to perform the functions recited by the means.

[0129] As discussed above, component 199 is configured to establish a sidelink connection with at least one first UE via a first PCC or a second PCC. At least one first PCC and at least one first SCC may be associated with a first transmission of at least one first UE. The second PCC and the second SCC may be associated with a second transmission of the second UE. The sidelink connection with at least one first UE may be associated with carrier aggregation. Component 199 may be further configured to receive a first indication of at least one of the following: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) at least one first SCC or second SCC is capable of maintaining the sidelink connection. Component 199 may be further configured to switch the sidelink connection from at least one first PCC to at least one first SCC or from a second PCC to a second SCC based on the first indication. Component 199 may be further configured to send a second indication of switching of the sidelink connection from at least one first PCC to at least one first SCC or from a second PCC to a second SCC. Component 199 may be within the cellular baseband processor 1124, the application processor 1106, or both the cellular baseband processor 1124 and the application processor 1106. Component 199 may be one or more hardware components specifically configured to perform the process / algorithm, implemented by one or more processors configured to perform the process / algorithm, stored in a computer-readable medium for implementation by one or more processors, or some combination thereof. As shown, the device 1104 may include a variety of components configured for various functions. In one configuration, the device 1104, and specifically the cellular baseband processor 1124 and / or the application processor 1106, includes a component for establishing a sidelink connection with at least one first UE via a first PCC or a second PCC. The device 1104 may also include a component for receiving a first indication of at least one of the following: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) at least one first SCC or a second SCC is able to maintain a sidelink connection. The device 1104 may also include: a component for switching the side link connection from at least one first PCC to at least one first SCC or from a second PCC to a second SCC based on the first indication. The device 1104 may also include: a component for sending a second indication of switching the side link connection from at least one first PCC to at least one first SCC or from a second PCC to a second SCC. The device 1104 may also include: a component for receiving a first notification that at least one first PCC is associated with at least one first UE. The method may also include: sending a second notification that the second PCC is associated with the second UE. The device 1104 may also include: a component for receiving at least a first transmission from at least one first UE via at least one first PCC. The method may also include sending at least a second transmission to the first UE via the second PCC.The device 1104 may also include: a component for receiving a PCC configuration for at least one first SCC or a second SCC. The device 1104 may also include: a component for switching the side link connection from at least one first PCC to at least one first SCC in response to detecting that at least one RSRP value of at least one first PCC or a second PCC is less than or equal to an RSRP threshold. The device 1104 may also include: a component for receiving a third indication of RLF, the third indication indicating a failure of the side link connection to switch from at least one first PCC or a second PCC to at least one first SCC or a second SCC. The device 1104 may also include: a component for switching the first side link connection from at least one first PCC to at least one first SCC based on channel reciprocity between at least one first PCC and a second PCC in response to switching the second side link connection from the second PCC to the second SCC. The device 1104 may also include: a component for activating a first timer for a third transmission of a first side link RRC reconfiguration for a first side link connection with a first UE via at least one first PCC after activating a second timer for a fourth transmission of a second side link RRC reconfiguration for a second side link connection with at least one first UE via at least one first PCC. The component may be a component 199 of the device 1104 configured to perform the functions recorded by the component. As described above, the device 1104 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 a controller / processor 375 configured to perform the functions recorded by the component.

[0130] 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 each block in a sample order, but are not limited to the specific order or hierarchy provided.

[0131] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not limited to the various aspects described herein, but should be given the full scope consistent with the language claims. Unless otherwise specified, references to singular elements do not mean "one and only one", but "one or more". References to a "set" or "subset" of an element mean that the set or subset has at least one element or may have multiple elements, but a set or subset of elements may not have zero elements. 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 an advantage over other aspects. Unless otherwise specified, the term "some" refers to one or more. Combinations such as "at least one of A, B or C", "one or more of A, B or C", "at least one of A, B and C", "one or more of A, B and C", and "A, B, C or any combination thereof" include any combination of A, B and / or C, 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, wherein any such combination may contain one or more members of A, B or C. A set should be interpreted as a set of elements, wherein the number of elements is one or more. Therefore, for a set of X, X will include one or more elements. If the first device receives data from the second device or sends data to the 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. All structural and functional equivalents of the elements of the various aspects described throughout the present disclosure that are known or will later become 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.The words “module,” “mechanism,” “element,” “device,” etc. cannot replace the word “means.” Thus, no claim element will be construed as means-plus-function unless the element is explicitly recited using the phrase “means for….”

[0132] 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.

[0133] A device configured to "output" data (such as, transmit, signal or message) may, for example, transmit the data with a transceiver, or may transmit the data to a device that transmits the data. A device configured to "obtain" data (such as, transmit, signal or message) may, for example, receive the data with a transceiver, or may obtain the data from a device that receives the data.

[0134] The following aspects are merely illustrative and may be combined with other aspects or teachings described herein without limitation.

[0135] Aspect 1 is a method for wireless communication at a first UE, the method may include: establishing a sidelink connection with at least one second UE via a first PCC or at least one second PCC. The first PCC and a first set of SCCs may be associated with a first transmission of the first UE. The at least one second PCC and at least one second set of SCCs may be associated with a second transmission of the at least one second UE. The sidelink connection with the at least one second UE may be associated with carrier aggregation. The method may also include: detecting at least one of the following: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) at least one SCC in the first set of SCCs or at least one SCC in at least one second set of SCCs is capable of maintaining the sidelink connection. The method may also include: sending a first indication of at least one of the following: (i) the sidelink connection is associated with the RLF value within the RLF threshold of the RLF limit, or (ii) the at least one SCC in the first set of SCCs or the at least one SCC in at least one second set of SCCs is capable of maintaining the sidelink connection. The method may further include receiving, based on the first indication, a second indication of switching the sidelink connection from the first PCC to a first SCC in the first set of SCCs or from the at least one second PCC to at least a second SCC in at least one second set of SCCs.

[0136] Aspect 2 is a method according to aspect 1, wherein the method may further include: sending a first notification that the first PCC is associated with the first UE. The method may further include: receiving a second notification that the at least one second PCC is associated with the at least one second UE.

[0137] Aspect 3 is a method according to aspect 2, wherein the first notification can be sent in a first set of SSB SIBs, or the second notification can be received in a second set of SSB SIBs.

[0138] Aspect 4 is a method according to any one of aspects 1 to 3, wherein the method may further include: sending at least the first transmission to the at least one second UE via the first PCC. The method may further include: receiving at least the second transmission from the at least one second UE via the at least one second PCC.

[0139] Aspect 5 is a method according to any one of Aspects 1 to 4, wherein the RLF value may include at least one of the following: the number of RLC retransmissions of the side link connection, a timer indicating the transmission of a side link RRC reconfiguration for the side link connection, or the number of consecutive HARQ DTXs for the destination of the side link connection.

[0140] Aspect 6 is a method according to any one of Aspects 1 to 5, wherein the method may further include: in response to detecting that at least one RSRP value of at least one SCC in the first set of SCCs or at least one SCC in at least one second set of SCCs is greater than or equal to an RSRP threshold, detecting that at least one SCC in the first set of SCCs or at least one SCC in at least one second set of SCCs is able to maintain the side link connection.

[0141] Aspect 7 is a method according to any one of aspects 1 to 6, wherein the method may further include: sending a first update for a first PCC configuration for the first set of SCCs in response to detecting that at least one SCC in the first set of SCCs is capable of maintaining the sidelink connection. The method may further include: sending a second update for a second PCC configuration for the at least one SCC in the second set of SCCs in response to detecting that at least one SCC in the second set of SCCs is capable of maintaining the sidelink connection.

[0142] Aspect 8 is a method according to any one of aspects 1 to 7, wherein the method may further include: sending a first update for a first PCC configuration for a first set of SCCs in response to detecting that at least one first RSRP value of at least one SCC in the first set of SCCs is greater than a first set of detected RSRP values ​​of other SCCs associated with the first transmission of the first UE. The method may also include: sending a second update for a second PCC configuration for at least one second set of SCCs in response to detecting that at least one second RSRP value of at least one SCC in at least one second set of SCCs is greater than a second set of detected RSRP values ​​of other SCCs associated with the second transmission of the at least one second UE.

[0143] Aspect 9 is a method according to any one of aspects 1 to 8, wherein the method may further include: sending a first update for a first PCC configuration for a first set of SCCs in response to detecting that at least one first RSRP value of the first PCC is less than or equal to an RSRP threshold. The method may also include: sending a second update for a second PCC configuration for at least one second set of SCCs in response to detecting that at least one second RSRP value of the at least one second PCC is less than or equal to the RSRP threshold.

[0144] Aspect 10 is a method according to aspect 9, wherein the first update for the first PCC configuration may be sent in a MAC-CE or SCI transmission.

[0145] Aspect 11 is a method according to any one of aspects 1 to 10, wherein the method may further include: in response to a first failure of the side link connection to be switched from the first PCC to the first SCC in the first set of SCCs, sending a third indication of a first RLF. The method may further include: in response to a second failure of the side link connection to be switched from the at least one second PCC to the at least second SCC in the at least one second set of SCCs, sending a fourth indication of a second RLF.

[0146] Aspect 12 is a method according to any one of aspects 1 to 11, wherein the first PCC and the at least one second PCC may have overlapping resources. In response to detecting that the first PCC is associated with the RLF value within the RLF threshold of the RLF limit, the first indication may include an indication that the at least one second PCC is associated with the RLF value within the RLF threshold of the RLF limit.

[0147] Aspect 13 is a method according to any one of aspects 1 to 12, wherein the first PCC and the at least one second PCC may have overlapping resources. The method may also include: synchronizing a first timer with a second timer. The first timer may be associated with a first sidelink RRC reconfiguration for a first sidelink connection with the at least one second UE via the first PCC. The second timer may be associated with a second sidelink RRC reconfiguration for a second sidelink connection with the at least one second UE via the at least one second PCC.

[0148] Aspect 14 is a method for wireless communication at a second UE, the method may include: establishing a sidelink connection with at least one first UE via a first PCC or a second PCC. The at least one first PCC and at least one first set of SCCs may be associated with a first transmission of the at least one first UE. The second PCC and the second set of SCCs may be associated with a second transmission of the second UE. The sidelink connection with the at least one first UE may be associated with carrier aggregation. The method may also include: receiving a first indication of at least one of the following: (i) the sidelink connection is associated with an RLF value within an RLF threshold of an RLF limit, or (ii) at least one SCC in at least one first set of SCCs or at least one SCC in the second set of SCCs is capable of maintaining the sidelink connection. The method may also include: switching the sidelink connection from the at least one first PCC to at least a first SCC in at least one first set of SCCs, or from the second PCC to a second SCC in the second set of SCCs based on the first indication. The method may further include sending a second indication of the switching of the sidelink connection from the at least one first PCC to the at least first SCC of the first set of SCCs or from the second PCC to the second SCC of the second set of SCCs.

[0149] Aspect 15 is a method according to aspect 14, wherein the method may further include: receiving a first notification that the at least one first PCC is associated with the at least one first UE. The method may further include: sending a second notification that the second PCC is associated with the second UE.

[0150] Aspect 16 is a method according to aspect 15, wherein the first notification may be received in a first set of SSB SIBs or the second notification may be sent in a second set of SSB SIBs.

[0151] Aspect 17 is a method according to any one of aspects 14 to 16, wherein the method may further include: receiving at least the first transmission from the at least one first UE via the at least one first PCC. The method may further include: sending at least the second transmission to the at least one first UE via the second PCC.

[0152] Aspect 18 is a method according to any one of Aspects 14 to 17, wherein the RLF value may include at least one of the following: the number of RLC retransmissions of the side link connection, a timer indicating the transmission of a side link RRC reconfiguration for the side link connection, or the number of consecutive HARQ DTXs for the destination of the side link connection.

[0153] Aspect 19 is a method according to any one of Aspects 14 to 18, wherein the first indication that at least one first set of the SCCs or the second set of the SCCs is capable of maintaining the side link connection may include: at least one RSRP value of at least one first set of the SCCs or the second set of the SCCs is greater than or equal to an RSRP threshold.

[0154] Aspect 20 is a method according to any one of aspects 14 to 19, wherein the method may further include: receiving an update for a PCC configuration for at least one first set of SCCs or the second set of SCCs.

[0155] Aspect 21 is a method according to any one of aspects 14 to 20, wherein the at least first SCC in the first set of SCCs may have at least one first RSRP value greater than a first set of detected RSRP values ​​of a first set of other SCCs associated with the first transmission of the at least one first UE. The second SCC in the second set of SCCs may have at least one second RSRP value greater than a second set of detected RSRP values ​​of a second set of other SCCs associated with the second transmission of the second UE.

[0156] Aspect 22 is a method according to any one of aspects 14 to 21, wherein the method may further include: in response to detecting that at least one first RSRP value of the at least one first PCC is less than or equal to an RSRP threshold, switching the side link connection from the at least one first PCC to the at least first SCC in the first set of SCCs. The method may also include: in response to detecting that at least one second RSRP value of the second PCC is less than or equal to the RSRP threshold, switching the side link connection from the second PCC to the second SCC in the second set of SCCs.

[0157] Aspect 23 is a method according to any one of Aspects 14 to 22, wherein the method may further include: receiving a third indication of RLF, the third indication indicating a switching failure of the side link connection from the at least one first PCC to the at least first SCC in the first set of SCCs or from the second PCC to the second SCC in the second set of SCCs.

[0158] Aspect 24 is a method according to aspect 23, wherein the third indication may be received in a MAC-CE or SCI transmission.

[0159] Aspect 25 is a method according to any one of Aspects 14 to 24, wherein the method may also include: in response to switching the second side link connection from the second PCC to the second SCC, switching the first side link connection from at least one first PCC to the at least one first SCC based on channel reciprocity between the at least one first PCC and the second PCC.

[0160] Aspect 26 is a method according to any one of aspects 14 to 25, wherein the at least one first PCC and the second PCC may have overlapping resources. The method may also include: after activating a second timer for a fourth transmission of a second sidelink RRC reconfiguration for a second sidelink connection with the at least one first UE via the second PCC, activating a first timer for a third transmission of a first sidelink RRC reconfiguration for a first sidelink connection with the first UE via the at least one first PCC.

[0161] Aspect 27 is an apparatus for performing wireless communications at a UE, comprising: a memory; and at least one processor, the at least one processor being coupled to the memory and being configured to implement any one of Aspects 1 to 26 based at least in part on information stored in the memory.

[0162] Aspect 28 is the apparatus of aspect 27, the apparatus further comprising: at least one of an antenna or a transceiver coupled to the at least one processor.

[0163] Aspect 29 is an apparatus for wireless communication, comprising means for implementing any one of aspects 1 to 26.

[0164] Aspect 30 is a computer-readable medium (eg, a non-transitory computer-readable medium) storing computer-executable code, wherein the code, when executed by a processor, causes the processor to implement any one of aspects 1 to 26.

Claims

1. An apparatus for wireless communication at a first user equipment (UE), comprising: Memory; and at least one processor coupled to the memory and based at least in part on the information stored in the memory, the at least one processor configured to: establishing a sidelink connection with at least one second UE via a first primary component carrier (PCC) or at least one second PCC, wherein the first PCC and a first set of secondary component carriers (SCCs) are associated with a first transmission of the first UE, wherein the at least one second PCC and at least one second set of SCCs are associated with a second transmission of the at least one second UE, and wherein the sidelink connection with the at least one second UE is associated with carrier aggregation (CA); detecting at least one of: (i) the sidelink connection is associated with a radio link failure (RLF) value within an RLF threshold of an RLF limit, or (ii) at least one SCC in the first set of SCCs or at least one SCC in at least one second set of SCCs is capable of maintaining the sidelink connection; sending a first indication of at least one of: (i) the sidelink connection is associated with the RLF value within the RLF threshold of the RLF limit, or (ii) the at least one SCC in the first set of SCCs or the at least one SCC in at least one second set of SCCs is capable of maintaining the sidelink connection; as well as A second indication of switching of the sidelink connection from the first PCC to a first SCC in the first set of SCCs or from the at least one second PCC to at least a second SCC in at least one second set of SCCs is received based on the first indication.

2. The apparatus according to claim 1, further comprising: a transceiver coupled to the at least one processor, wherein the at least one processor is further configured to: Sending, using the transceiver, a first notification that the first PCC is associated with the first UE; or A second notification is received using the transceiver that the at least one second PCC is associated with the at least one second UE.

3. The apparatus of claim 2, wherein the first notification is sent in a first set of synchronization signal blocks (SSBs) system information blocks (SIBs), or the second notification is received in a second set of SSB SIBs.

4. The apparatus of claim 1 , wherein the at least one processor is further configured to: Send at least the first transmission to the at least one second UE via the first PCC; or At least the second transmission is received from the at least one second UE via the at least one second PCC.

5. The apparatus of claim 1 , wherein the RLF value comprises at least one of: a number of radio link control (RLC) retransmissions for the sidelink connection, a timer indicating a transmission of a sidelink radio resource control (RRC) reconfiguration for the sidelink connection, or a number of consecutive hybrid automatic repeat request (HARQ) discontinuous transmissions (DTX) for a destination of the sidelink connection.

6. The apparatus according to claim 1, wherein the at least one processor is further configured to: detect that the at least one SCC in the first set of SCCs or the at least one SCC in the at least one second set of SCCs is able to maintain the sidelink connection in response to detecting that at least one reference signal received power (RSRP) value of the at least one SCC in the first set of SCCs or the at least one SCC in the at least one second set of SCCs is greater than or equal to an RSRP threshold.

7. The apparatus of claim 1, wherein the at least one processor is further configured to: sending a first update for a first PCC configuration for the first set of SCCs in response to detecting that at least one SCC in the first set of SCCs is capable of maintaining the sidelink connection; or A second update for a second PCC configuration for the at least one SCC in the second set of SCCs is sent in response to detecting that the at least one SCC in the second set of SCCs is capable of maintaining the sidelink connection.

8. The apparatus of claim 1, wherein the at least one processor is further configured to: transmitting a first update for a first PCC configuration for the first set of SCCs in response to detecting that at least one first RSRP value of the at least one SCC in the first set of SCCs is greater than a first set of detected RSRP values ​​of other SCCs associated with the first transmission of the first UE; or In response to detecting that at least one second RSRP value of at least one SCC in at least one second set of the SCCs is greater than the detected RSRP values ​​of a second set of other SCCs associated with the second transmission of the at least one second UE, a second update for a second PCC configuration for at least one second set of the SCCs is sent.

9. The apparatus of claim 1 , wherein the at least one processor is further configured to: sending a first update for a first PCC configuration for a first set of SCCs in response to detecting that at least one first RSRP value of the first PCC is less than or equal to an RSRP threshold; or A second update for a second PCC configuration for at least one second set of SCCs is sent in response to detecting that at least one second RSRP value of the at least one second PCC is less than or equal to the RSRP threshold.

10. The apparatus of claim 9, wherein the first update for the first PCC configuration is sent in a Medium Access Control (MAC) Control Element (MAC-CE) or Sidelink Control Information (SCI) transmission.

11. The apparatus of claim 1 , wherein the at least one processor is further configured to: sending a third indication of a first RLF in response to a first failure of switching the sidelink connection from the first PCC to the first SCC in the first set of SCCs; or A fourth indication of a second RLF is sent in response to a second failure of switching the sidelink connection from the at least one second PCC to the at least second SCC of the at least one second set of SCCs.

12. The apparatus of claim 1 , wherein the first PCC and the at least one second PCC have overlapping resources, and wherein in response to detecting that the first PCC is associated with the RLF value within the RLF threshold of the RLF limit, the first indication comprises an indication that the at least one second PCC is associated with the RLF value within the RLF threshold of the RLF limit.

13. An apparatus according to claim 1, wherein the first PCC and the at least one second PCC have overlapping resources, and wherein the at least one processor is further configured to synchronize a first timer with a second timer, wherein the first timer is associated with a first sidelink RRC reconfiguration for a first sidelink connection with the at least one second UE via the first PCC, and wherein the second timer is associated with a second sidelink RRC reconfiguration for a second sidelink connection with the at least one second UE via the at least one second PCC.

14. An apparatus for wireless communication at a second user equipment (UE), comprising: Memory; and at least one processor coupled to the memory and based at least in part on the information stored in the memory, the at least one processor configured to: establishing a sidelink connection with at least one first UE via at least one first primary component carrier (PCC) or a second PCC, wherein the at least one first PCC and at least one first set of secondary component carriers (SCCs) are associated with a first transmission of the at least one first UE, wherein the second PCC and a second set of SCCs are associated with a second transmission of the second UE, and wherein the sidelink connection with the at least one first UE is associated with carrier aggregation (CA); receiving a first indication of at least one of: (i) the sidelink connection is associated with a radio link failure (RLF) value within an RLF threshold of an RLF limit, or (ii) at least one SCC in at least one first set of SCCs or at least one SCC in the second set of SCCs is able to maintain the sidelink connection; switching the sidelink connection from the at least one first PCC to at least a first SCC in at least one first set of SCCs, or from the second PCC to a second SCC in the second set of SCCs based on the first indication; as well as A second indication of the switching of the sidelink connection from the at least one first PCC to the at least first SCC of the first set of SCCs or from the second PCC to the second SCC of the second set of SCCs is sent.

15. The apparatus according to claim 14, further comprising: a transceiver coupled to the at least one processor, wherein the at least one processor is further configured to: receiving, using the transceiver, a first notification that the at least one first PCC is associated with the at least one first UE; or A second notification is sent using the transceiver that the second PCC is associated with the second UE.

16. The apparatus of claim 15, wherein the first notification is received in a first set of synchronization signal blocks (SSBs) system information blocks (SIBs), or the second notification is sent in a second set of SSB SIBs.

17. The apparatus of claim 14, wherein the at least one processor is further configured to: receiving at least the first transmission from the at least one first UE via the at least one first PCC; or At least the second transmission is sent to the at least one first UE via the second PCC.

18. The apparatus of claim 14, wherein the RLF value comprises at least one of: a number of radio link control (RLC) retransmissions for the sidelink connection, a timer indicating a transmission of a sidelink radio resource control (RRC) reconfiguration for the sidelink connection, or a number of consecutive hybrid automatic repeat request (HARQ) discontinuous transmissions (DTX) for a destination of the sidelink connection.

19. The apparatus of claim 14, wherein the first indication that at least one first set of the SCCs or the second set of the SCCs is capable of maintaining the sidelink connection comprises at least one reference signal received power (RSRP) value of at least one first set of the SCCs or the second set of the SCCs being greater than or equal to an RSRP threshold.

20. The apparatus of claim 14, wherein the at least one processor is further configured to: An update to a PCC configuration for at least one of the first set of SCCs or the second set of SCCs is received.

21. The apparatus of claim 14, wherein the at least the first SCC in the first set of SCCs has at least one first RSRP value of a first set that is greater than detected RSRP values ​​of a first set of other SCCs associated with the first transmission of the at least one first UE, or wherein the second SCC in the second set of SCCs has at least one second RSRP value of a second set that is greater than detected RSRP values ​​of a second set of other SCCs associated with the second transmission of the second UE.

22. The apparatus of claim 14, wherein the at least one processor is further configured to: switching the sidelink connection from the at least one first PCC to the at least first SCC in the first set of SCCs in response to detecting that at least one first RSRP value of the at least one first PCC is less than or equal to an RSRP threshold; or The sidelink connection is switched from the second PCC to the second SCC in the second set of SCCs in response to detecting that at least one second RSRP value of the second PCC is less than or equal to the RSRP threshold.

23. The apparatus of claim 14, wherein the at least one processor is further configured to: A third indication of RLF is received, the third indication indicating a handover failure of the sidelink connection from the at least one first PCC to the at least the first SCC in the first set of SCCs or from the second PCC to the second SCC in the second set of SCCs.

24. The apparatus of claim 23, wherein the third indication is received in a Medium Access Control (MAC) Control Element (MAC-CE) or a Sidelink Control Information (SCI) transmission.

25. The apparatus of claim 14, wherein the at least one processor is further configured to: In response to switching the second side link connection from the second PCC to the second SCC in the second set of SCCs, switching the first side link connection from the at least one first PCC to the at least first SCC in the first set of SCCs based on channel reciprocity between the at least one first PCC and the second PCC.

26. An apparatus according to claim 14, wherein the at least one first PCC and the second PCC have overlapping resources, and wherein the at least one processor is further configured to associate a second timer with a first timer, wherein the first timer is associated with a first side link RRC reconfiguration for a first side link connection with the at least one first UE via the at least one first PCC, and wherein the second timer is associated with a second side link RRC reconfiguration for a second side link connection with the at least one first UE via the second PCC.

27. A method of wireless communication at a first user equipment (UE), comprising: establishing a sidelink connection with at least one second UE via a first primary component carrier (PCC) or at least one second PCC, wherein the first PCC and a first set of secondary component carriers (SCCs) are associated with a first transmission of the first UE, wherein the at least one second PCC and at least one second set of SCCs are associated with a second transmission of the at least one second UE, and wherein the sidelink connection with the at least one second UE is associated with carrier aggregation (CA); detecting at least one of: (i) the sidelink connection is associated with a radio link failure (RLF) value within an RLF threshold of an RLF limit, or (ii) at least one SCC in the first set of SCCs or at least one SCC in at least one second set of SCCs is capable of maintaining the sidelink connection; sending a first indication of at least one of: (i) the sidelink connection is associated with the RLF value within the RLF threshold of the RLF limit, or (ii) the at least one SCC in the first set of SCCs or the at least one SCC in at least one second set of SCCs is capable of maintaining the sidelink connection; as well as A second indication of switching of the sidelink connection from the first PCC to a first SCC in the first set of SCCs or from the at least one second PCC to at least a second SCC in at least one second set of SCCs is received based on the first indication.

28. The method according to claim 27, further comprising: Sending a first notification that the first PCC is associated with the first UE; or A second notification is received that the at least one second PCC is associated with the at least one second UE.

29. A method of wireless communication at a second user equipment (UE), comprising: establishing a sidelink connection with at least one first UE via at least one first primary component carrier (PCC) or a second PCC, wherein at least one set of the at least one first PCC and a first secondary component carrier (SCC) is associated with a first transmission of the at least one first UE, and a second set of the second PCC and the SCC is associated with a second transmission of the second UE, and wherein the sidelink connection with the at least one first UE is associated with carrier aggregation (CA); receiving a first indication of at least one of: (i) the sidelink connection is associated with a radio link failure (RLF) value within an RLF threshold of an RLF limit, or (ii) at least one of the first set of SCCs or the second set of SCCs is capable of maintaining the sidelink connection; switching the sidelink connection from the at least one first PCC to at least a first SCC in the first set of SCCs, or from the second PCC to a second SCC in the second set of SCCs based on the first indication; as well as A second indication of the switching of the sidelink connection from the at least one first PCC to the at least first SCC of the first set of SCCs or from the second PCC to the second SCC of the second set of SCCs is sent.

30. The method of claim 29, further comprising: receiving a first notification that the at least one first PCC is associated with the at least one first UE; or Send a second notification that the second PCC is associated with the second UE.

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