CN116724520A - Rapid SCELL activation - Google Patents

Abstract

The UE may receive an activation indication for the SCell from the serving cell, receive a first reference signal from the SCell, the first reference signal including at least one temporary reference signal, identify whether a second reference signal is received after processing the activation indication and before expiration of an SCell activation time, and, upon identifying that the second reference signal is received, activate the SCell based on one or more reference signals including at least one of the first reference signal or the second reference signal. The UE may activate the SCell no later than in time slot n+k, and K may be determined based at least in part on the SCell activation time.

Description

Rapid SCELL activation

Cross Reference to Related Applications

The present application claims priority and the benefit of U.S. provisional application Ser. No. 63/135,472 and 2021, filed on 1/8 and titled "METHOD AND APPARATUS FOR FAST SCELL ACTIVATION", and U.S. patent application Ser. No. 17/546,941, titled "FAST SCELL ACTIVATION", both of which are expressly incorporated herein by reference in their entirety.

Technical Field

The present disclosure relates generally to communication systems, and more particularly, to methods of wireless communication that include fast secondary cell (SCell) activation using a temporary Reference Signal (RS).

Background

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcast. A typical wireless communication system may employ multiple-access techniques capable of supporting communication with multiple users by sharing the available system resources. Examples of such multiple-access techniques 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.

These multiple access techniques have been adopted in a variety of telecommunications standards to provide a universal protocol that enables different wireless devices to communicate at the urban, national, regional, or even global level. An example telecommunications standard is 5G New Radio (NR). The 5G NR is part of the continuous mobile broadband evolution promulgated by the third generation partnership project (3 GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the internet of things (IoT)), and other requirements. The 5G NR includes services associated with enhanced mobile broadband (emmbb), large-scale machine type communication (emtc), and ultra-reliable low latency communication (URLLC). Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. There is a need for further improvements in 5G NR technology. These improvements may also be applicable to other multiple access techniques and communication standards employing these techniques.

Disclosure of Invention

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

In one aspect of the disclosure, methods, computer-readable media, and apparatuses are provided. An apparatus may be a User Equipment (UE), may receive an activation indication for an SCell from a serving cell, receive a first reference signal from the SCell, the first reference signal including at least one temporary reference signal, identify whether a second reference signal is received after processing the activation indication and before expiration of an SCell activation time, and, upon identifying that the second reference signal is received, activate the SCell based on one or more reference signals including at least one of the first reference signal or the second reference signal. The UE may activate the SCell no later than in time slot n+k, and K may be determined based at least in part on the SCell activation time.

The UE may send an Acknowledgement (ACK) to the serving cell for receipt of an activation indication, wherein the activation indication is processed for a first duration after sending the ACK to the serving cell. The UE may send a Channel State Information (CSI) report based on which the UE activates one of the first reference signal or the second reference signal of the SCell.

The UE may activate the SCell no later than in time slot n+k, and K may be determined based at least in part on the SCell activation time. In one aspect, the activation indication may be received via one of a Medium Access Control (MAC) Control Element (CE) (MAC-CE) or Downlink Control Information (DCI), and the at least one temporary reference signal includes an aperiodic tracking reference signal, and the activation indication indicates an aperiodic tracking reference signal transmitted by the SCell. The SCell activation time may be an SCell activation time between transmission of the ACK of the activation indication and a second duration after receiving the at least one temporary reference signal.

In another aspect, the activation indication may be received via Radio Resource Control (RRC) signaling and the at least one temporary reference signal includes a periodic tracking reference signal, and the activation indication indicates the periodic tracking reference signal transmitted by the SCell. The SCell activation time may be an SCell activation time between transmission of an ACK of the activation indication and a second duration after receiving a last one of the one or more reference signals based on which the UE activates the SCell. The activation indication may indicate that a plurality of scells are activated simultaneously, and the plurality of scells may be in the same frequency band, in adjacent carriers in the same frequency band, or in a frequency range.

The UE may receive an activation indication for the SCell from the serving cell based on the first reference signal, the activation indication indicating transmission of the first reference signal for activating the SCell, identify whether the first reference signal is transmitted as indicated, and activate the SCell based on one or more reference signals including the first reference signal or the second reference signal when the first reference signal is identified as being transmitted as indicated. The UE may send an ACK to the serving cell for receiving an activation indication, wherein the activation indication is processed for a first duration after sending the ACK to the serving cell.

The first reference signal may include at least one of a periodic tracking reference signal or an aperiodic tracking reference signal. The UE may identify whether the first reference signal is transmitted as indicated by the activation indication by performing a clear channel assessment to determine whether the channel measurement is greater than a threshold, and in response to determining that the channel measurement is greater than the threshold, identify that the first reference signal is not transmitted as indicated by the activation indication.

The UE may receive an instruction to cancel transmission of the first reference signal from the serving cell, wherein the UE identifies that the first reference signal is not transmitted in response to receiving the instruction to cancel the first reference signal, and wherein the instruction to cancel the activation indication for the SCell based on the first reference signal is indicated by one of MAC-CE or DCI.

The UE may receive a second reference signal from the SCell when it is identified that the first reference signal is not being transmitted as indicated, and activate the SCell based on the second reference signal received from the SCell when it is identified that the first reference signal is not being transmitted as indicated. The SCell activation time may be an SCell activation time between transmission of the ACK of the activation indication and a second duration after receiving the second reference signal.

The UE may receive a new activation indication indicating transmission of a second reference signal for activating the SCell, wherein upon receiving the new activation indication, the UE identifies that the first reference signal was not transmitted as indicated.

The activation indication may indicate that a plurality of scells are activated simultaneously, and the plurality of scells may be in the same frequency band, in adjacent carriers in the same frequency band, or in a frequency range.

To the accomplishment of the foregoing and related ends, one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed and the present specification is intended to include all such aspects and their equivalents.

Drawings

Fig. 1 is a schematic diagram illustrating an example of a wireless communication system and an access network.

Fig. 2A is a schematic diagram illustrating an example of a first frame in accordance with aspects of the present disclosure.

Fig. 2B is a schematic diagram illustrating an example of DL channels within a subframe in accordance with aspects of the present disclosure.

Fig. 2C is a schematic diagram illustrating an example of a second frame in accordance with aspects of the present disclosure.

Fig. 2D illustrates a schematic diagram of an example of UL channels within a subframe in accordance with various aspects of the present disclosure.

Fig. 3 is a schematic diagram showing an example of a base station and a User Equipment (UE) in an access network.

Fig. 4 illustrates an example of SCell activation for wireless communication.

Fig. 5 illustrates an example of SCell activation for wireless communication.

Fig. 6 illustrates an example of SCell activation for wireless communication.

Fig. 7 shows a call flow diagram for wireless communication.

Fig. 8 is a flow chart of a method of wireless communication.

Fig. 9 is a flow chart of a method of wireless communication.

Fig. 10 illustrates an example of SCell activation for wireless communication.

Fig. 11 illustrates an example of SCell activation for wireless communication.

Fig. 12 shows a call flow diagram for wireless communication.

Fig. 13 is a flow chart of a method of wireless communication.

Fig. 14 is a flow chart of a method of wireless communication.

Fig. 15 is a schematic diagram illustrating an example of a hardware implementation for an example apparatus.

Detailed Description

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be implemented. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. It will be apparent, however, to one skilled in the art that the concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

Aspects of a telecommunications system are now presented with reference to various apparatus and methods. These devices and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, and the like (collectively, "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

By way of example, an element, or any portion of an element, or any combination of elements, may be implemented as a "processing system" comprising one or more processors. Examples of processors include microprocessors, microcontrollers, graphics Processing Units (GPUs), central Processing Units (CPUs), application processors, digital Signal Processors (DSPs), reduced Instruction Set Computing (RISC) processors, system-on-chip (SoC), baseband processors, field Programmable Gate Arrays (FPGAs), programmable Logic Devices (PLDs), state machines, gate logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout this disclosure. One or more processors in the processing system may execute the software. Software should be construed broadly to mean instructions, instruction sets, code segments, program code, programs, subroutines, software components, applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, and the like, whether referred to as software, firmware, middleware, microcode, hardware description language, or other terminology.

Thus, in one or more example embodiments, the functions described may be implemented in hardware, software, or any combination thereof. When implemented in software, the functions may be stored or encoded on a computer-readable medium as one or more instructions or code. Computer readable media includes computer storage media. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise 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 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 and that can be accessed by a computer.

While aspects and implementations of the application are described by way of illustration of some examples, those skilled in the art will appreciate that additional implementations and use cases may occur in many different arrangements and scenarios. The innovations described herein may be implemented across many different platform types, devices, systems, shapes, sizes, and/or packaging arrangements. For example, implementations and/or use cases may be implemented via integrated chip implementations or other non-module component based devices (e.g., end user devices, vehicles, communication devices, computing devices, industrial devices, retail/purchase devices, medical devices, artificial Intelligence (AI) enabled devices, etc.). While some examples may or may not be specific to use cases or applications, the innovations described may present a wide variety of applicability. Implementations may range from chip-level or modular components to non-modular, non-chip-level implementations, and further to aggregate, distributed, or Original Equipment Manufacturer (OEM) devices or systems that incorporate one or more aspects of the described innovations. In some practical arrangements, devices incorporating the described aspects and features may also include other components and features for implementing and practicing the claimed and described aspects. For example, the transmission and reception of wireless signals must include a number of components for analog and digital purposes (e.g., hardware components including antennas, RF chains, power amplifiers, modulators, buffers, processors, interleavers, adders/accumulators, etc.). It is contemplated that the innovations described herein may be practiced in a wide variety of devices, chip-scale components, systems, distributed arrangements, aggregated or disaggregated components, end-user devices, etc., having different sizes, shapes, and configurations.

Fig. 1 is a schematic diagram illustrating an example of a wireless communication system and an access network 100. A wireless communication system, also referred to as a Wireless Wide Area Network (WWAN), includes a base station 102, a UE 104, an Evolved Packet Core (EPC) 160, and another core network 190 (e.g., a 5G core (5 GC)). Base station 102 may include a macrocell (high power cellular base station) and/or a small cell (low power cellular base station). The macrocell includes a base station. Small cells include femto cells, pico cells, and micro cells.

A base station 102 configured for 4G LTE, collectively referred to as an evolved Universal Mobile Telecommunications System (UMTS) terrestrial radio access network (E-UTRAN), may interface with the EPC 160 over a first backhaul link 132 (e.g., an S1 interface). A base station 102 configured for 5G NR (collectively referred to as a next generation RAN (NG-RAN)) may interface with the core network 190 over a second backhaul link 184. Among other functions, the base station 102 may perform one or more of the following functions: transmission of user data, wireless channel encryption and decryption, integrity protection, header compression, mobile control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio Access Network (RAN) sharing, multimedia Broadcast Multicast Services (MBMS), user and device tracking, RAN Information Management (RIM), paging, positioning, and delivery of alert messages. The base stations 102 may communicate with each other directly or indirectly (e.g., through the EPC 160 or the core network 190) over a third backhaul link 134 (e.g., an X2 interface). The first backhaul link 132, the second backhaul link 184, and the third backhaul link 134 may be wired or wireless.

The base station 102 may communicate wirelessly with the UE 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, the small cell 102 'may have a coverage area 110' that overlaps with the coverage area 110 of one or more macro base stations 102. A network comprising both small cells and macro cells may be referred to as a heterogeneous network. The heterogeneous network may also include home evolved node B (eNB) (HeNB) and the HeNB may provide services to a restricted group called a Closed Subscriber Group (CSG). The communication link 120 between the base station 102 and the UE 104 may include Uplink (UL) (also referred to as a reverse link) transmissions from the UE 104 to the base station 102 and/or Downlink (DL) (also referred to as a forward link) transmissions from the base station 102 to the UE 104. Communication link 120 may use multiple-input multiple-output (MIMO) antenna techniques including spatial multiplexing, beamforming, and/or transmit diversity. The communication link may be through one or more carriers. The base station 102/UE 104 may be a spectrum of up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc., MHz) per carrier allocated for carrier aggregation of up to yxmhz (x component carriers) in total for transmission in each direction. These carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL than UL). The component carriers may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell) and the secondary component carrier may be referred to as a secondary cell (SCell).

Some UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use the DL/UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels such as a Physical Sidelink Broadcast Channel (PSBCH), a Physical Sidelink Discovery Channel (PSDCH), a Physical Sidelink Shared Channel (PSSCH), and a Physical Sidelink Control Channel (PSCCH). The D2D communication may be through various wireless D2D communication systems, such as WiMedia, bluetooth, zigBee, wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

The wireless communication system may also include a Wi-Fi Access Point (AP) 150, the AP 150 communicating with Wi-Fi Stations (STAs) 152 via a communication link 154, e.g., in a 5GHz unlicensed spectrum or the like. When communicating in the unlicensed spectrum, STA 152/AP 150 may perform Clear Channel Assessment (CCA) prior to the communication to determine whether a channel is available.

The small cell 102' may operate in licensed and/or unlicensed spectrum. When operating in unlicensed spectrum, the small cell 102' may employ NR and use the same unlicensed spectrum (e.g., 5GHz, etc.) as used by the Wi-Fi AP 150. Small cells 102' employing NRs in unlicensed spectrum may improve coverage and/or increase access network capacity.

Typically, the electromagnetic spectrum is subdivided into various categories, bands, channels, etc., based on frequency/wavelength. In 5G NR, two initial operating bands have been identified as frequency range names FR1 (410 MHz-7.125 GHz) and FR2 (24.25 GHz-52.6 GHz). Although a portion of FR1 is greater than 6GHz, FR1 is often (interchangeably) referred to as the "below 6GHz" band in various documents and literature. Similar naming problems sometimes occur with respect to FR2, which is commonly (interchangeably) referred to as the "millimeter wave" band in various documents and literature, although it is different from the Extremely High Frequency (EHF) band (30 GHz-300 GHz) identified by the International Telecommunications Union (ITU) as the "millimeter wave" band.

The frequency between FR1 and FR2 is commonly referred to as the mid-band frequency. Recent 5G NR studies have identified the operating band for these mid-band frequencies as frequency range designation FR3 (7.125 GHz-24.25 GHz). The frequency band falling within FR3 may inherit FR1 characteristics and/or FR2 characteristics and may therefore effectively extend the characteristics of FR1 and/or FR2 to mid-band frequencies. In addition, higher frequency bands are currently being explored to extend 5G NR operation above 52.6 GHz. For example, three higher operating bands have been identified as frequency range names FR2-2 (52.6 GHz-71 GHz), FR4 (71 GHz-114.25 GHz) and FR5 (114.25 GHz-300 GHz). Each of these higher frequency bands falls within the EHF frequency band.

In view of the above, unless explicitly stated otherwise, it should be understood that the term "below 6GHz" and the like (if used herein) may broadly represent frequencies less than 6GHz, may be within FR1, or may include mid-band frequencies. Furthermore, unless explicitly stated otherwise, it should be understood that the term "millimeter wave" or the like (if used herein) may broadly refer to frequencies including mid-band frequencies, may be within FR2, FR4, FR2-2 and/or FR5, or may be within the EHF band.

Base station 102, whether small cell 102' or a large cell (e.g., macro base station), may include and/or be referred to as an eNB, a gndeb (gNB), or another type of base station. Some base stations (such as the gNB 180) may operate in the traditional frequency spectrum below 6GHz, in millimeter wave frequencies, and/or in near millimeter wave frequencies to communicate with the UE 104. When the gNB 180 operates in millimeter wave or near millimeter wave frequencies, the gNB 180 may be referred to as a millimeter wave base station. Millimeter-wave base station 180 may utilize beamforming 182 with UE 104 to compensate for path loss and short distance. The base station 180 and the UE 104 may each include multiple antennas (e.g., antenna elements, antenna panels, and/or antenna arrays) to facilitate beamforming.

The base station 180 may transmit the beamformed signals to the UE 104 in one or more transmit directions 182'. The UE 104 may receive the beamformed signals from the base station 180 in one or more receive directions 182 ". The UE 104 may also transmit the beamformed signals to the base station 180 in one or more transmit directions. The base station 180 may receive beamformed signals from the UEs 104 in one or more receive directions. The base station 180/UE 104 may perform beam training to determine the best reception and transmission direction for each of the base station 180/UE 104. The transmit and receive directions for base station 180 may or may not be the same. The transmit and receive directions for the UE 104 may or may not be the same.

EPC 160 may include a Mobile Management Entity (MME) 162, other MMEs 164, a serving gateway 166, a Multimedia Broadcast Multicast Service (MBMS) gateway 168, a broadcast multicast service center (BM-SC) 170, and a Packet Data Network (PDN) gateway 172.MME 162 may communicate with a Home Subscriber Server (HSS) 174. The MME 162 is a control node that handles signaling between the UE 104 and the EPC 160. In general, MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are communicated through the serving gateway 166, which serving gateway 166 itself is connected to the PDN gateway 172. The PDN gateway 172 provides UE IP address allocation as well as other functions. The PDN gateway 172 and BM-SC 170 are connected to an IP service 176.IP services 176 may include the internet, intranets, IP Multimedia Subsystem (IMS), and PS streaming services and/or other IP services. The BM-SC 170 may provide functionality for MBMS user service provisioning and delivery. The BM-SC 170 may act as an entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services in a Public Land Mobile Network (PLMN), and may be used to schedule MBMS transmissions. The MBMS gateway 168 may be used to distribute MBMS traffic to base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and collecting charging information related to eMBMS.

The core network 190 may include access and mobility management functions (AMFs) 192, other AMFs 193, session Management Functions (SMFs) 194, and User Plane Functions (UPFs) 195. The AMF 192 may communicate with a Unified Data Management (UDM) 196. The AMF 192 is a control node that handles signaling between the UE 104 and the core network 190. In general, AMF 192 provides QoS flows and session management. All user Internet Protocol (IP) packets are transmitted through UPF 195. The UPF 195 provides UE IP address assignment as well as other functions. The UPF 195 is connected to an IP service 197.IP services 197 may include internet, intranet, IP Multimedia Subsystem (IMS), packet Switched (PS) streaming (PSs) services, and/or other IP services.

A base station may include and/or be referred to as a gNB, a node B, eNB, an access point, a base station transceiver, 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), or some other suitable terminology. The base station 102 provides an access point for the UE 104 to the EPC 160 or core network 190. Examples of UEs 104 include a cellular telephone, a smart phone, a Session Initiation Protocol (SIP) phone, a laptop, a Personal Digital Assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electricity meter, an air pump, a large or small kitchen appliance, a medical device, an implant, a sensor/actuator, a display, or any other similar functional device. Some of the UEs 104 may be referred to as IoT devices (e.g., parking meters, air pumps, toasters, vehicles, heart monitors, etc.). The UE 104 may also be referred to as a station, mobile station, subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, or some other suitable terminology. In some scenarios, the term UE may also apply to one or more companion devices, such as in a device constellation arrangement. One or more of these devices may access the network in common and/or individually.

Referring again to fig. 1, in certain aspects, the UE 104 may include an SCell activation component 198, the SCell activation component 198 configured to: an activation indication for an SCell is received from a serving cell, a first reference signal is received from the SCell, the first reference signal including at least one temporary reference signal, whether a second reference signal is received after processing the activation indication and before expiration of an SCell activation time is identified, and the SCell is activated based on one or more reference signals including at least one of the first reference signal or the second reference signal when the second reference signal is identified as received. Although the following description focuses on 5G NR, the concepts described herein may be applied to other similar fields, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

Fig. 2A is a diagram 200 illustrating an example of a first subframe within a 5G NR frame structure. Fig. 2B is a diagram 230 illustrating an example of DL channels within a 5G NR subframe. Fig. 2C is a diagram 250 illustrating an example of a second subframe within a 5G NR frame structure. Fig. 2D is a diagram 280 illustrating an example of UL channels within a 5G NR subframe. The 5G NR frame structure may be Frequency Division Duplex (FDD) where subframes within a set of subcarriers are dedicated to DL or UL for a particular set of subcarriers (carrier system bandwidth) or Time Division Duplex (TDD) where subframes within a set of subcarriers are dedicated to both DL and UL for a particular set of subcarriers (carrier system bandwidth). In the example provided by fig. 2A, 2C, it is assumed that the 5G NR frame structure is TDD, with subframe 4 configured with slot format 28 (mainly DL), where D is DL, U is UL, and F is flexibly used between DL/UL, and subframe 3 is configured with slot format 1 (all UL). Although subframes 3, 4 are shown as having slot formats 1, 28, respectively, any particular subframe may be configured with any of the various available slot formats 0-61. The slot formats 0, 1 are full DL, full UL, respectively. Other slot formats 2-61 include a mix of DL, UL and flexible symbols. The UE is configured with a slot format (dynamically configured by DL Control Information (DCI) or semi-statically/statically configured by Radio Resource Control (RRC) signaling) through a received Slot Format Indicator (SFI). Note that the following description also applies to the 5G NR frame structure of TDD.

Fig. 2A-2D illustrate frame structures, and aspects of the present disclosure may be applicable to other wireless communication technologies that may have different frame structures and/or different channels. A frame (10 ms) may be divided into 10 subframes (1 ms) of the same size. Each subframe may include one or more slots. The subframe may also include a minislot, which may include 7, 4, or 2 symbols. Each slot may include 14 or 12 symbols depending on whether the Cyclic Prefix (CP) is normal or extended. For a normal CP, each slot may include 14 symbols, and for an extended CP, each slot may include 12 symbols. The symbols on DL may be CP Orthogonal Frequency Division Multiplexing (OFDM) (CP-OFDM) symbols. The symbols on the UL may be CP-OFDM symbols (for high throughput scenarios) or Discrete Fourier Transform (DFT) -spread OFDM (DFT-s-OFDM) symbols (also known as single carrier frequency division multiple access (SC-FDMA) symbols) (for power limited scenarios; limited to single stream transmission). The number of slots within a subframe is based on CP and digital scheme (numerology). The digital scheme defines a subcarrier spacing (SCS) and effectively defines a symbol length/duration (which is equal to 1/SCS).

For a normal CP (14 symbols/slot), different digital schemes μ0 to 4 allow 1, 2, 4, 8 and 16 slots, respectively, per subframe. For extended CP, digital scheme 2 allows 4 slots per subframe. Thus, for the normal CP and digital scheme μ, there are 14 symbols/slot and 2 ^μ Each slot/subframe. The subcarrier spacing may be equal to 2 ^μ *15kHz, where μ is the digital schemes 0 through 4. As such, the digital scheme μ=0 has a subcarrier spacing of 15kHz, and the digital scheme μ=4 has a subcarrier spacing of 240 kHz. The symbol length/duration is inversely related to the subcarrier spacing. Figures 2A-2D provide a normal CP with 14 symbols per slot and a per subframeThere is an example of a digital scheme μ=2 of 4 slots. The slot duration is 0.25ms, the subcarrier spacing is 60kHz, and the symbol duration is approximately 16.67 mus. Within a group of frames, there may be one or more different bandwidth portions (BWP) of the frequency division multiplexing (see fig. 2B). Each BWP may have a specific digital scheme and CP (normal or extended).

The resource grid may be used to represent a frame structure. Each slot includes Resource Blocks (RBs) (also referred to as Physical RBs (PRBs)) containing 12 consecutive subcarriers. The resource grid is divided into a plurality of Resource Elements (REs). The number of bits carried by each RE depends on the modulation scheme.

As shown in fig. 2A, some of the REs carry a reference (pilot) signal (RS) for the UE. The RSs may include demodulation RSs (DM-RSs) for channel estimation at the UE (for one particular configuration, indicated as R, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RSs). The RSs may also include beam measurement RSs (BRSs), beam refinement (BRRSs), and phase tracking RSs (PT-RSs).

Fig. 2B shows an example of various DL channels within a subframe of a frame. A Physical Downlink Control Channel (PDCCH) carries DCI in 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. The PDCCH within one 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., common search space, UE-specific search space) on CORESET during a PDCCH monitoring occasion, wherein the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWP may be located at higher and/or lower frequencies across the channel bandwidth. The Primary Synchronization Signal (PSS) may be within symbol 2 of a particular subframe of a frame. PSS is used by the UE 104 to determine subframe/symbol timing and physical layer identity. The Secondary Synchronization Signal (SSS) may be located within symbol 4 of a particular subframe of a frame. The SSS is used by the UE to determine the physical layer cell identification group number and the radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE may determine a Physical Cell Identifier (PCI). Based on the PCI, the UE can determine the location of the DM-RS. A Physical Broadcast Channel (PBCH) carrying a Master Information Block (MIB) may be logically grouped with 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 a System Frame Number (SFN). The Physical Downlink Shared Channel (PDSCH) carries user data, broadcast system information, such as System Information Blocks (SIBs), which are not transmitted over the PBCH, and paging messages.

As shown in fig. 2C, some of the REs carry DM-RS for channel estimation at the base station (indicated as R for one particular configuration, but other DMRS configurations are possible). The UE may transmit DM-RS for a Physical Uplink Control Channel (PUCCH) and DM-RS for a Physical Uplink Shared Channel (PUSCH). The PUSCH DM-RS may be transmitted in the previous or two symbols of the PUSCH. The PUCCH DM-RS may be transmitted in different configurations depending on whether a short or long PUCCH is transmitted and depending on the specific PUCCH format used. The UE may transmit a Sounding Reference Signal (SRS). The SRS may be transmitted in the last symbol of the subframe. The SRS may have a comb structure, and the UE may transmit the SRS on one of the combs. The SRS may be used by the base station for channel quality estimation to enable frequency dependent scheduling on the UL.

Fig. 2D shows examples of various UL channels within a subframe of a frame. The PUCCH may be located as indicated in one configuration. The PUCCH carries Uplink Control Information (UCI) such as a scheduling request, a Channel Quality Index (CQI), a Precoding Matrix Indicator (PMI), a Rank Indicator (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)). PUSCH carries data and may additionally be used to carry Buffer Status Reports (BSR), power Headroom Reports (PHR), and/or UCI.

Fig. 3 is a block diagram of a base station 310 in communication with a UE 350 in an access network. In DL, IP packets from EPC 160 may be provided to controller/processor 375. Controller/processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a Radio Resource Control (RRC) layer, and layer 2 includes a Service Data Adaptation Protocol (SDAP) layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, and a Medium Access Control (MAC) layer. Controller/processor 375 provides RRC layer functions associated with: broadcast of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), movement between Radio Access Technologies (RATs), and measurement configuration for UE measurement reporting; PDCP layer functions associated with: header compression/decompression, security (encryption, decryption, integrity protection, integrity verification) and handover support functions; RLC layer functions associated with: transmission of upper layer Packet Data Units (PDUs), error correction by ARQ, concatenation, segmentation and reassembly of RLC Service Data Units (SDUs), re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; MAC layer functions associated with: mapping between logical channels and transport channels, multiplexing of MAC SDUs onto Transport Blocks (TBs), de-multiplexing of TB-to-MAC SDUs, scheduling information reporting, error correction by HARQ, priority handling, and logical channel prioritization.

Transmit (TX) processor 316 and Receive (RX) processor 370 implement layer 1 functions associated with various signal processing functions. Layer 1, including the Physical (PHY) layer, may include: error detection on a transmission channel, forward Error Correction (FEC) encoding/decoding of the transmission channel, interleaving, rate matching, mapping to physical channels, modulation/demodulation of the physical channels, and MIMO antenna processing. TX processor 316 processes the mapping for the signal constellation 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 encoded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to OFDM subcarriers, multiplexed with reference signals (e.g., pilots) in the time and/or frequency domain, and then combined together using an inverse fourier transform (IFFT) to produce a physical channel carrying the time domain OFDM symbol stream. The OFDM streams are spatially precoded to produce a plurality of spatial streams. The channel estimates from the channel estimator 374 may be used to determine the coding and modulation scheme and for spatial processing. The channel estimate may be derived from reference signals and/or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318 TX. Each transmitter 318TX may modulate a Radio Frequency (RF) carrier with a respective spatial stream for transmission.

At the UE 350, each receiver 354RX receives a signal through its respective antenna 352. Each receiver 354RX recovers information modulated onto an RF carrier and provides the information to the Receive (RX) processor 356.TX processor 368 and RX processor 356 implement layer 1 functions associated with various signal processing functions. RX processor 356 can perform spatial processing on the information to recover any spatial streams destined for UE 350. If multiple spatial streams are destined for the UE 350, they may be combined into a single OFDM symbol stream by the RX processor 356. The RX processor 356 then transforms 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 OFDMA symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, as well as the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. These soft decisions may be based on channel estimates computed by channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the base station 310 on the physical channel. The data and control signals are then provided to a controller/processor 359 that implements layer 3 and layer 2 functions.

The controller/processor 359 can be associated with a memory 360 that stores program codes and data. Memory 360 may be referred to as a computer-readable medium. In the UL, controller/processor 359 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from EPC 160. The controller/processor 359 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

Similar to the functionality described in connection with DL transmissions by the base station 310, the controller/processor 359 provides RRC layer functions associated with: system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement report; PDCP layer functions associated with: header compression/decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functions associated with: transmission of upper layer PDUs, error correction by ARQ, concatenation, segmentation and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; MAC layer functions 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 by HARQ, priority handling, and logical channel prioritization.

Channel estimates, derived by channel estimator 358 from reference signals or feedback transmitted by base station 310, may be used by TX processor 368 to select appropriate coding and modulation schemes and facilitate spatial processing. The spatial streams generated by TX processor 368 may be provided to different antenna 352 via separate transmitters 354 TX. Each transmitter 354TX may modulate an RF carrier with a respective spatial stream for transmission.

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

The controller/processor 375 may be associated with a memory 376 that stores program codes and data. Memory 376 may be referred to as a computer-readable medium. In the UL, controller/processor 375 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from UE 350. IP packets from controller/processor 375 may be provided to EPC 160. Controller/processor 375 is also responsible for error detection using ACK and/or NACK protocols to support HARQ operations.

At least one of TX processor 368, RX processor 356, and controller/processor 359 may be configured to perform aspects related to 198 of fig. 1.

In some aspects of wireless communication, one or more active serving cells may instruct a UE to activate deactivated scells for carrier aggregation. The one or more active serving cells may include a PCell connected to the UE or another active serving SCell. The UE may receive SCell activation commands or indications from one or more active serving cells and, upon receiving the SCell activation indications, the UE may receive Synchronization Signal Blocks (SSBs) from the deactivated scells and activate the deactivated scells. To activate the deactivated SCell, the UE may perform at least one procedure including SSB detection, fine time/frequency tracking, or Automatic Gain Control (AGC) setting to activate the SCell.

The UE may be no later than in slot n when receiving the SCell activation indication in slot nIn sending a valid CSI report and applying an action related to an activation indication for the SCell being activated, wherein T is in milliseconds (ms) _HARQ Is the period of time between DL data transmission of the SCell activation indication and Acknowledgement (ACK) of the transmission activation indication, T _{activation_time} SCell activation delay in ms and T _{CSI_reporting} Is the delay uncertainty in acquiring one or more first available CSI reporting resources. For example, the ACK may be a hybrid automatic repeat request (HARQ) ACK 424.

In some aspects, T may be determined based on a time slot in which SSB is received from the SCell and at least one procedure performed by the UE to activate the SCell _{activation_time} . In one aspect, when the UE is known to the SCell and the SCell measurement period is less than or equal to 160ms, the UE may perform fine time/frequency tracking to activate the SCell. That is, if the UE knows the SCell and the SCell measurement period is less than or equal to 160ms, the UE may perform fine time/frequency tracking using one (1) SSBs to activate the SCell. Accordingly, T _{activation_time} May be T _FirstSSB +T _FirstDelay +T _SecondDelay Wherein T is _FirstDelay Can be used forIs the processing time of the SCell activation indication received after sending the ACK of the activation indication, T _FirstSSB May be the time between processing the activation indication and the transmission of the first complete SSB burst, and T _SecondDelay May be the processing time of the first full SSB burst received after the transmission of the first full SSB burst. For example T _FirstDelay May be 3ms, and T _SecondDelay May be 2ms. In such a case, T _{activation_time} May be T _FirstSSB +5ms, and T _FirstSSB May be in time slotAnd then to the end of the first complete SSB burst.

In one aspect, when the UE is known to the SCell and the SCell measurement period is greater than 160ms, the UE may perform fine time/frequency tracking and AGC settings to activate the SCell. That is, if the UE knows the SCell and the SCell measurement period is greater than 160ms, the UE may perform fine time/frequency tracking and AGC setting using two (2) SSBs to activate the SCell. Accordingly, T _{activation_time} May be T _{FirstSSB_MAX} +T _rs +T _FirstDelay +T _SecondDelay Wherein T is _FirstDelay Is the processing time of the SCell activation indication received after sending the ACK of the activation indication, T _{FirstSSB_MAX} Is the time between processing the activation indication and the transmission of the first complete SSB burst, T _rs Is based on the RRM measurement timing configuration (SMTC) period or the measured object period or SSB frequency of SSB, and T _SecondDelay Is the processing time of the first full SSB burst received after the transmission of the first full SSB burst. For example T _FirstDelay May be 3ms, and T _SecondDelay May be 2ms. In such a case, T _{activation_time} May be T _{FirstSSB_MAX} +T _rs +5ms, and T _{FirstSSB_MAX} May be at the time slotThe time of the end of the following first complete SSB burst.

In one aspect, when the SCell is unknown to the UE, the UE may perform fine time/frequency tracking, AGC setting, and SSB detection to activate the SCell. That is, if the SCell is unknown to the UE, the UE may perform fine time/frequency tracking, AGC setting, and SSB detection using four (4) SSBs to activate the SCell. Accordingly, T _{activation_time} May be T _{FirstSSB_MAX} +T _{SMTC_MAX} +2T _rs +T _FirstDelay +T _SecondDelay Wherein T is _FirstDelay Is the processing time of the SCell activation indication received after sending the ACK of the activation indication, T _{FirstSSB_MAX} Is the time between processing the activation indication and the transmission of the first complete SSB burst, T _rs Is the SMTC period or the measured object period or SSB frequency, T _{SMTC_MAX} Is a longer SMTC period between the active serving cell and SCell activated, and T _SecondDelay Is the processing time of the first full SSB burst received after the transmission of the first full SSB burst. For example T _FirstDelay May be 3ms, and T _SecondDelay May be 2ms. In such a case, T _{activation_time} May be T _{FirstSSB_MAX} +T _{SMTC_MAX} +2T _rs +5ms, and T _{FirstSSB_MAX} May be at the time slot The time of the end of the following first complete SSB burst.

In some aspects, one or more temporary RSs may be provided to accelerate the SCell activation procedure. In particular, the PCell may configure one or more temporary RSs for the SCell and the UE, and the SCell may transmit the temporary RSs to the UE. The UE may reduce latency in activating scells for carrier aggregation by activating scells based on one or more temporary RSs and thus speed up the SCell activation procedure for efficient SCell activation for both FR1 and FR 2. The UE may be during the SCell activation procedure based on the temporary RS received from the SCell AGC setting and time/frequency tracking are performed. The UE may measure the temporary RS received from the SCell and generate and transmit CSI reports. The UE may also perform cell search for the SCell based on the received temporary RS. That is, the UE may reduce T by activating the SCell based at least in part on one or more temporary RSs _{activation_Time} 。

The temporary RSs may include one or more aperiodic tracking RSs and/or periodic tracking RSs including, but not limited to, aperiodic CSI-RSs, periodic/semi-persistent CSI-RSs, PSS-or SSS-based SRS and RSs. The aperiodic tracking RS may be triggered by DCI or MAC-CE, and the periodic tracking RS may be triggered by RRC signal. Aspects of the present disclosure may be applicable to FR1 and may be extended to FR2.

Fig. 4 illustrates an example of SCell activation 400 for wireless communication. Examples of SCell activation 400 include SCell 410 and PCell 420. Here, PCell 420 is one or more active serving cells from which UE and SCell 410 may receive SCell activation indication 422. The SCell may transmit SSB 412 in SSB periods, and the SCell may transmit temporary RS 418 based on SCell activation indication 422 received from PCell 420. Fig. 4 shows that the temporary RS 418 is an aperiodic tracking RS, but aspects of the present disclosure are not limited thereto, and the temporary RS 418 may be a periodic tracking RS.

The UE may receive an SCell activation indication 422 from the PCell 420, the SCell activation indication 422 indicating that the UE activates the deactivated SCell 410 based on the temporary RS 418 received from the SCell 410. Upon receiving the SCell activation indication 422, the UE may send an ACK and process the received SCell activation indication 422. For example, the ACK may be a HARQ ACK 424 transmitted in response to the received SCell activation indication. The UE may receive the temporary RS 418 from the SCell 410 and activate the SCell 410 based on the temporary RS 418. To activate the SCell 410, the ue may perform at least one procedure including SSB detection, fine time/frequency tracking, or AGC setting to activate the SCell based on the temporary RS 418 received from the PCell 420.

The UE may be no later than in slot n when SCell activation indication 422 is received in slot nIn which a valid CSI report is sent and actions related to the activation indication 422 are applied for the SCell being activated, where T is in milliseconds (ms) _HARQ Is the period between DL data transmission of the SCell activation indication 422 and the HARQ ACK 424 sending the activation indication, T _{activation_time} Is SCell activation delay in ms, and T _{CSI_reporting} Is the delay uncertainty in acquiring one or more first available CSI reporting resources.

In some aspects, T may be determined based on a slot in which the temporary RS is received from SCell 410 and at least one procedure that the UE performs to activate SCell 410 _{activation_time} . In one aspect, when the UE knows the SCell 410 and the SCell measurement period is less than or equal to 160ms, the UE may perform fine time/frequency tracking to activate the SCell 410. That is, if the UE knows the SCell 410 and the SCell measurement period is less than or equal to 160ms, the UE may perform fine time/frequency tracking using one (1) RSs including temporary RSs to activate the SCell 410. Accordingly, T _{activation_time} May be T _{Temp_RS} +T _FirstDelay +T _SecondDelay Wherein T is _FirstDelay Is the processing time for the received SCell activation indication 422 after sending the HARQ ACK 424 for the SCell activation indication 422, and T _SecondDelay Is the processing time of the received first temporary RS 418 after the transmission of the first temporary RS 418. T (T) _{temp RS} May be T after transmission of HARQ ACK 424, at the time between processing the activation indication and transmission of the first temporary RS 418 _firstDelay Time between transmission with the first temporary RS 418. For example T _FirstDelay May be 3ms, and T _SecondDelay May be 2ms. In such a case, T _{activation_time} May be T _{Temp_RS} +5ms, and T _{Temp_RS} May be at the time slotThe time of the end of the following first complete RS burst. / >

Fig. 4 shows that the first temporary RS 418 can satisfy T _{activation_time} And the UE may activate SCell 410 based on the first temporary RS 418. However, aspects of the present disclosure are not limited thereto, and the UE may use a power signal capable of satisfying T _{activation_time} Is not present in the RS. The SCell activation indication may be transmitted through a MAC-CE, DCI, or RRC signal. That is, upon SCell addition/handover/RRC recovery, RRC-based direct SCell activation is possible. Furthermore, SSBs and/or periodic tracking RSs configured by RRC signaling may not be triggered/cancelled by MAC-CE/DCI on the SCell to be activated. That is, the RRC signal may configure the periodic tracking RS for the SCell and the UE directly at the SCell addition/handover/RRC recovery, and the periodic tracking RS may not be triggered or cancelled by the MAC-CE or DCI. The MAC-CE of the DCI may also configure the aperiodic tracking RS.

The UE may use one or more RSs from the set of RSs for SCell activation in the same or different serving cells, subject to the SCell activation delay being met. That is, a deactivated SCell or other SCell may transmit one or more RSs for SCell activation, and the UE may use any of the RSs in the RS set (including all or a subset of SSBs, periodically tracked RSs, or aperiodically tracked RSs) as long as the SCell activation delay is satisfied. That is, as long as one or more RSs for SCell activation satisfy T _{activation_time} The UE may use at least one of the one or more RSs for SCell activation.

Fig. 5 illustrates an example of SCell activation 500 for wireless communication. Examples of SCell activation 500 include SCell 510 and PCell 520. The example of SCell activation 500 for wireless communication shows that SCell 510 may be activated using a first temporary RS 518 and T may follow transmission of HARQ ACK 524 _firstDelay And T _{activation_time} Between expiration, SSB 512 is received. The first temporary RS 518 may be an aperiodic tracking RS triggered by DCI or MAC-CE.

Referring to fig. 5, if UE processing of SCell activation indication 522 received via DCI or MAC-CE is completed before 't=ack time+3 ms', SSB 512 received after 't=ack time+3 ms' may be available. Thus, the UE may activate SCell 510 using SSB 512. The UE may use one or more RSs (including SSBs, periodic tracking RSs, and/or indicated aperiodic tracking RSs) for AGC settings, or fine time/frequency tracking for SCell activation. That is, the timing of the first temporary RS 518 for T may be determined based on the trigger _{activation timie} And the UE may utilize any RS (including SSB/periodically tracking RS/aperiodically tracking RS) as long as the necessary procedures can be performed within the window.

The UE may not be later than in slot n when SCell activation indication 522 is received in slot nIn which a valid CSI report is sent and actions related to SCell activation indication 522 are applied for the SCell being activated, where T is in milliseconds (ms) _HARQ Is the period between DL data transmission of the SCell activation indication 522 and the HARQ ACK 524 sending the activation indication, T _{activation_time} Is SCell activation delay in ms, and T _{CSI_reporting} Is the delay uncertainty in acquiring one or more first available CSI reporting resources.

In some aspects, T may be determined based on a slot in which a temporary RS is received from SCell510 and at least one procedure performed by the UE to activate SCell510 _{activation_time} . In one aspect, when the UE is aware of the SCell510 and the SCell measurement period is less than or equal to 160ms, the UE may perform fine time/frequency tracking to activate the SCell 510. That is, if the UE knows the SCell510 and the SCell measurement period is less than or equal to 160ms, the UE may perform fine time/frequency tracking using one (1) temporary RSs to activate the SCell 510. Accordingly, T _{activation_time} May be T _{Temp_RS} +T _FirstDelay +T _SecondDelay Wherein T is _FirstDelay Is the processing time of the SCell activation indication 522 received after the HARQ ACK 524 of the SCell activation indication 522 is sent, while T _SecondDelay Is the processing time of the first temporary RS 518 received after the transmission of the first temporary RS 518. If the first is next toWhen RS is triggered for SCell activation, T is no matter whether UE actually uses the first temporary RS to activate SCell _{temp RS} Can be all from' T _HARQ The duration of +3ms' starting to the end of the last OFDM symbol or last slot of the first temporary RS. That is, T _{temp RS} May be T after transmission of HARQ ACK 524, at the time between processing the activation indication and transmission of the first temporary RS 518 _firstDelay Time between transmission with the first temporary RS 518. For example T _FirstDelay May be 3ms, and T _SecondDelay May be 2ms. In such a case, T _{activation_time} May be T _{Temp_RS} +5ms, and T _{Temp_RS} May be at the time slotThe time after the end of the first complete RS burst.

For other cases (e.g., unknown cells), T _{activation time} The values of (2) may be different but the principle is the same. In one aspect, when the UE is known to the SCell and the SCell measurement period is greater than 160ms, the UE may perform fine time/frequency tracking and AGC settings to activate the SCell510. That is, if the UE knows the SCell and the SCell measurement period is greater than 160ms, the UE may perform fine time/frequency tracking and AGC setting using two (2) RSs including the first temporary RS 518 to activate the SCell510. Here, the UE may activate the SCell510 using the SSB 512 and the first temporary RS 518 as two (2) RSs including the first temporary RS 518. Accordingly, referring to FIG. 4, T may be taken as _{activation_time} Reduced to T _{Temp_RS} +T _FirstDelay +T _SecondDelay Wherein T is _FirstDelay Is the processing time of the SCell activation indication 522 received after the HARQ ACK 524 of the SCell activation indication 522 is sent, and T _SecondDelay Is the processing time of the first temporary RS 518 received after the transmission of the first temporary RS 518. T (T) _{Temp_RS} May be T after transmission of HARQ ACK 524, at the time between processing the activation indication and transmission of the first temporary RS 518 _firstDelay Time between transmission with the first temporary RS 518.For example T _FirstDelay May be 3ms, and T _SecondDelay May be 2ms. In such a case, T _{activation_time} May be T _{Temp_RS} +5ms, and T _{Temp_RS} May be at the time slotThe time after which the first complete SSB burst ends.

In one aspect, when the SCell is unknown to the UE and belongs to FR1, the UE may perform fine time/frequency tracking, AGC setting, and SSB detection to activate the SCell. That is, if the SCell is unknown to the UE, the UE may perform fine time/frequency tracking, AGC setting, and SSB detection using four (4) RSs including the first temporary RS 518 to activate the SCell. Here, the UE may use SSBs 512, 514, and 516 and a first temporary RS 518. Thus, referring to FIG. 4, T may be taken as _{activation_time} Reduced to T _FirstSSB +2T _rs +T _FirstDelay +T _SecondDelay Wherein T is _FirstDelay Is the processing time of the SCell activation indication received after sending the ACK of the activation indication, T _FirstSSB Is the time between processing the activation indication and transmitting the first complete SSB burst, T _rs Is SSB frequency, T _SecondDelay Is the processing time of the first full SSB burst received after transmission of the first full SSB burst. For example T _FirstDelay May be 3ms, T _SecondDelay May be 2ms. In this case T _{activation_time} May be T _FirstSSB +2T _rs +5ms, and T _{FirstSSB_MAX} May be at the time slotThe time of the end of the first complete SSB burst thereafter.

Thus, by using the first temporary RS 518, T can be reduced _{activation_time} And may accelerate SCell 510 activation. Further, if the periodic tracking RS is configured on a carrier that can be used for AGC or fine time/frequency tracking, and the periodic tracking RS falls intoIn the time period, the periodic tracking RS may be used as one or more RSs for use by the UE in place of or with the triggered first temporary RS. Referring to FIG. 5, for example, if the first temporary RS 518 is a non-zero power (NZP) CSI-RS (NZP-CSI-RS) with trs-Info' (where l e {4,8} for FR 1), then T _{temp RS} May be a duration of 1 slot +9 OFDM symbols (if the duration ends at the last OFDM symbol) and may be a duration of 2 slots (if the duration ends at the last slot).

Fig. 6 illustrates an example of SCell activation 600 for wireless communication. Examples of SCell activation 600 include SCell 610 and PCell 620. An example of SCell activation 500 for wireless communication shows that T after transmission of HARQ ACK 624 may be used _firstDelay And at T _{activation_time} The second temporary RS 619 received between before expiration activates the SCell 610. The second temporary RS 619 may be a periodic tracking RS and may not be triggered by DCI or MAC-CE, and an example of SCell activation 600 may be RRC-based direct SCell activation. That is, the SCell activation indication 622 may be an RRC signal. The UE may use one or more RSs, including SSBs and/or periodic tracking RSs, for AGC setting and/or fine time/frequency tracking for SCell activation. Here, T for a known cell with SCell measurement period less than or equal to 160ms _{activation time} May be T _RS +5ms where T _RS The timing of the SSB or periodically tracking the transmission of the RS is based on the first reception. That is, referring to fig. 6, if the second temporary RS 619 is T after transmission of the HARQ ACK 524 _firstDelay Later received, T _{activation_time} T possibly after transmission of the second temporary RS 619 _SecondDelay And expire. If SSB 612 is T after transmission of HARQ ACK 624 prior to second temporary RS 619 _firstDelay Later received, T _{activation_time} T which may follow the transmission of SSB 612 _SecondDelay And expire.

For other cases (e.g., unknown cells), T _{activation time} The values of (2) may be different but the principle is the same. Can be based on SSBOr periodically tracking the timing in the RS (based on the previous receipt) to determine the timing for T _{activation_time} And can be used for T as long as necessary _{activation time} The UE may utilize SSB and/or P-TRS. Thus T _{activation_time} May be T _FirstDelay +T _RS +T _SecondDelay Wherein T is _RS Is from' T _HARQ +3ms' starts until the UE determines the duration of the end of the last OFDM symbol or last slot of one or more RSs for SCell activation.

One or more of the RSs may be SSB or periodically tracking RS to at T _HARQ Earlier received after +3 ms. In one aspect, when the UE knows SCell 610 and the SCell measurement period is greater than 160ms, the UE may perform fine time/frequency tracking and AGC settings to activate SCell 610. That is, if the UE knows the SCell and the SCell measurement period is greater than 160ms, the UE may perform fine time/frequency tracking and AGC setting using two (2) RSs including SSB 612 and/or second temporary RS 619 to activate SCell 610. Thus T _{activation_time} May be T _FirstDelay +T _RS +T _SecondDelay Wherein T is _RS Is from' T _HARQ The +3ms' starts until the UE determines the duration of the end of the last OFDM symbol or the last slot of the second RS for SCell activation.

In one aspect, when SCell 610 is unknown to the UE and belongs to FR1, the UE may perform fine time/frequency tracking, AGC setting, and SSB detection to activate the SCell. That is, if the SCell is unknown to the UE, the UE may perform fine time/frequency tracking, AGC setting, and SSB detection using four (4) RSs including the second temporary RS 619 to activate the SCell 610. Thus T _{activation_time} May be T _FirstDelay +T _RS +T _SecondDelay Wherein T is _RS Is from' T _HARQ The +3ms' starts until the UE determines the duration of the end of the last OFDM symbol or the last slot of the fourth RS for SCell activation.

In some aspects, referring again to fig. 5 and 6, multiple scells may be activated simultaneously. The UE may activate multiple scells using SSBs and/or temporary RSs (including periodic or aperiodic tracking RSs transmitted in a serving cell different from the SCell to be activated). For example, if there is an active serving cell in the same frequency band as that used for the SCell to be activated, a temporary RS in the active serving cell may be used to activate the SCell. That is, in one aspect, when the SCell activation indication provides a plurality of scells to be activated simultaneously, the active serving cell may transmit a temporary RS on one of the plurality of scells to be activated, and the UE may activate the plurality of scells using the temporary RS transmitted on the one of the plurality of scells based on the SCell activation indication received from the active serving cell.

In some aspects, referring again to fig. 5 and 6, there may be multiple RSs including SSBs or temporary RSs including periodic tracking RSs and/or aperiodic tracking RSs associated with different TCI states/QCL hypotheses. That is, in the case of a beam scanning operation, multiple RSs provided on different beams may be associated with different TCI states/QCL hypotheses. Thus, the UE may use one or more RSs from SSBs or temporary RSs (including periodic tracking RSs or aperiodic tracking RSs associated with the same TCI state or QCL assumption). That is, the UE may use one or more RSs transmitted on the same beam and associated with the same TCI state/QCL assumption. Thus, the UE may assume that SSBs and/or temporary RSs (including periodic tracking RSs and aperiodic tracking RSs that can be used for AGC settings and/or fine time/frequency tracking) may be quasi co-sited. The network may also configure the TCI state of the RSs so that they should be quasi co-sited from the UE's point of view.

In some aspects, a temporary RS may be used to activate multiple scells of various configurations. In one aspect, multiple scells to be activated may be in the same frequency band. In another aspect, the plurality of scells to be activated may be adjacent carriers in the same frequency band. In another aspect, the plurality of scells to be activated may be in FR 2.

In some aspects, various configured temporary RSs may be used to activate the SCell. In one aspect, the UE may use an SSB received from an SCell of the plurality of scells to be activated or an earliest received RS of temporary RSs (including periodically tracked RSs or aperiodically tracked RSs). In another aspect, the UE may use earliest timing of received RSs of SSBs or temporary RSs (including periodically tracking RSs or aperiodically tracking RSs) transmitted on all of the plurality of scells to be activated. In another aspect, the UE may use the latest received RS of SSBs or temporary RSs (including periodic tracking RS or aperiodic tracking RS) transmitted on scells of the plurality of scells to be activated.

As indicated in fig. 5 and 6, the UE may perform a procedure other than fine time/frequency tracking to activate one or more scells. For example, the SCell may be unknown, or the SCell may be known, with a measurement period greater than 160ms. A temporary RS including a periodic tracking RS and/or an aperiodic tracking RS may refer to one or more temporary RS sets including a periodic tracking RS and/or an aperiodic tracking RS. Thus, one or more temporary RS sets including periodic tracking RS and/or aperiodic tracking RS received from an SCell to be activated after the first SSB or SSB burst may be considered as active RSs, and the UE may perform at least one procedure including SSB detection, fine time/frequency tracking, or Automatic Gain Control (AGC) setting to activate the SCell based on the SSB and/or the one or more temporary RS sets including periodic tracking RS and/or aperiodic tracking RS. The structure of the periodic/aperiodic tracking RS (including symbol position, number of slots, and/or number of resource sets) may be dynamically indicated and/or determined according to the state of the SCell to be activated. For example, the SCell may be a known or unknown SCell, and the SCell measurement period may be less than or equal to 160ms or greater than 160ms, and the structure of temporary RSs (including periodic tracking RSs or aperiodic tracking RSs) for activating the SCell may be dynamically configured to reduce latency in activating the SCell for carrier aggregation.

Fig. 7 illustrates a call flow diagram 700 for wireless communication. The call flow diagram 700 may include a UE 702, a serving cell 704, and an SCell 706 to be activated by the UE 702. The UE 702 may receive SCell activation commands or indications from one or more active serving cells (e.g., serving cell 704). One or more temporary RSs may be provided to accelerate the SCell activation procedure, and the UE 702 may accelerate the SCell activation procedure using the one or more temporary RSs received from the SCell 706.UE 702 may activate SCell 706 no later than in time slot n+k, and K may be determined based at least in part on the SCell activation time.

At 710, the UE 702 may receive an activation indication from the serving cell 704 to activate the SCell 706. The activation indication may be received via one of a MAC-CE, DCI or RRC signal. The activation indication may indicate that multiple scells 706 are activated simultaneously, the multiple scells 706 including a first SCell and a second SCell. The first SCell and the second SCell may be in the same frequency band, in adjacent carriers in the same frequency band, or in a frequency range. At 711, the serving cell 704 may configure the SCell 706 to transmit one or more RSs, including the first reference signal and/or the second reference signal.

At 712, the UE 702 may send an ACK to the serving cell 704 for receipt of an activation indication, wherein the activation indication is processed for a first duration after sending the ACK to the serving cell 704.

At 714, the UE 702 may process the activation indication received from the serving cell 704. The UE 702 may receive the first reference signal and/or the second reference signal based on the processed activation indication.

At 716, the UE 702 may receive a first reference signal from the SCell 706, the first reference signal comprising at least one temporary reference signal. The first reference signal may be a temporary RS including an aperiodic tracking RS indicated by a MAC-CE or DCI or a periodic tracking RS indicated by an RRC signal. Here, the first reference signal may be received from the active serving cell 704.

At 718, the UE 702 may receive a second reference signal from the SCell 706, the second reference signal comprising at least one temporary reference signal. The second reference signal may be an SSB or a temporary RS including an aperiodic tracking RS indicated by a MAC-CE or DCI or a periodic tracking RS indicated by an RRC signal. Here, the second reference signal may be received from the active serving cell 704. It may be assumed that the first reference signal and the second reference signal are quasi co-located with each other.

At 720, the UE 702 may identify whether a second reference signal is received after processing the activation indication and before expiration of the SCell activation time.

At 722, the UE 702 may generate a CSI report based on which the UE 702 activates one of the first reference signal or the second reference signal of the SCell 706.

At 724, the UE 702 may send a CSI report based on which the UE 702 activates one of the first reference signal or the second reference signal of the SCell 706.

At 726, the UE 702 may activate the SCell 706 based on one or more reference signals comprising at least one of the received first reference signal and/or second reference signal. The UE 702 may activate the SCell 706 based on one or more reference signals (including at least one of the first reference signal or the second reference signal) upon identifying receipt of the second reference signal. The UE 702 may receive the activation indication in time slot n and may activate SCell 706 no later than in time slot n+k, where K is determined based on at least one of: a time period between receiving an activation indication from a serving cell and sending an Acknowledgement (ACK) of the activation indication to the serving cell, an SCell activation time, and a delay uncertainty in acquiring one or more first available CSI reporting resources. For example, UE 702 may receive an activation indication in slot n and may be no later than in slot The SCell706 is activated. T (T) _{activation_time} May be an SCell activation time and determined based on one or more reference signals including at least one of the first reference signal or the second reference signal. In one aspect, the SCell activation time may be between transmission of an ACK of the activation indication and a second duration after receiving the at least one temporary reference signal. In another aspect, the SCell activation time may be after transmission of an ACK of the activation indication and a last reference signal of the one or more reference signals based on which the UE activated the SCellBetween the second durations. In another aspect, the SCell activation time may be between transmission of an ACK of the activation indication and a second duration after receiving two or four reference signals including one of the first reference signal or the second reference signal.

The UE 702 may simultaneously activate the plurality of scells 706 based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, whichever is received earliest from the plurality of scells 706. The UE 702 may activate the plurality of scells 706 based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, subject to receipt within an earliest activation time for the plurality of scells 706. The UE 702 may activate the plurality of scells 706 based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, subject to being received latest from among the plurality of scells 706.

Fig. 8 is a flow chart 800 of a method of wireless communication. The method may be performed by a UE (e.g., UE 104, 702; apparatus 1502). The UE may receive SCell activation commands or indications from one or more active serving cells (e.g., serving cells). One or more temporary RSs may be provided to accelerate the SCell activation procedure, and the UE may accelerate the SCell activation procedure using the one or more temporary RSs received from the SCell. The UE may activate the SCell no later than in time slot n+k, where K may be determined based at least in part on the SCell activation time.

At 802, the UE may receive an activation indication from a serving cell for activating an SCell. The activation indication may be received via one of a MAC-CE, DCI or RRC signal. The activation indication may indicate that multiple scells are activated simultaneously, the multiple scells including a first SCell and a second SCell. For example, at 710, the UE 702 may receive an activation indication from the serving cell 704 to activate the SCell 706. Further, 802 may be performed by SCell activation component 1540.

At 804, the UE may send an ACK to the serving cell for receiving an activation indication, wherein the activation indication is processed for a first duration after sending the ACK to the serving cell. For example, at 712, the UE 702 may send an ACK to the serving cell 704 for receipt of an activation indication, wherein the activation indication is processed for a first duration after sending the ACK to the serving cell 704. Further, 804 can be performed by ACK component 1542.

At 806, the UE may process the activation indication received from the serving cell. The UE may receive the first reference signal and/or the second reference signal based on the processed activation indication. For example, at 714, the UE 702 may process the activation indication received from the serving cell 704. Further, 806 may be performed by SCell activation component 1540.

At 808, the UE may receive a first reference signal from the SCell, the first reference signal comprising at least one temporary reference signal (i.e., as at 716). The first reference signal may be a temporary RS including an aperiodic tracking RS indicated by a MAC-CE or DCI or a periodic tracking RS indicated by an RRC signal. Here, the first reference signal may be received from an active serving cell. For example, at 716, the UE 702 may receive a first reference signal from the SCell706, the first reference signal comprising at least one temporary reference signal. Further, 808 may be performed by SCell activation component 1540.

At 810, the UE may receive a second reference signal from the SCell, the second reference signal comprising at least one temporary reference signal (i.e., as at 718). The second reference signal may be an SSB or a temporary RS including an aperiodic tracking RS indicated by a MAC-CE or DCI or a periodic tracking RS indicated by an RRC signal. Here, the second reference signal may be received from an active serving cell. It may be assumed that the first reference signal and the second reference signal are quasi co-located with each other. For example, at 718, the UE 702 may receive a second reference signal from the SCell706, the second reference signal comprising at least one temporary reference signal. Furthermore, 810 may be performed by SCell activation component 1540.

At 812, the UE may identify whether a second reference signal is received after processing the activation indication and before expiration of the SCell activation time (i.e., as at 720). For example, at 720, the UE 702 may identify whether a second reference signal is received after processing the activation indication and before expiration of the SCell activation time. Further, 812 may be performed by SCell activation component 1540.

At 814, the UE may generate a CSI report based on which the UE activates one of the first reference signal or the second reference signal of the SCell (i.e., as at 722). For example, at 722, the UE 702 may generate a CSI report based on which the UE 702 activates one of the first reference signal or the second reference signal of the SCell 706. Further, 814 may be performed by CSI component 1544.

At 816, the UE may send a CSI report based on which the UE activates one of the first reference signal or the second reference signal of the SCell (i.e., as at 724). For example, at 724, the UE 702 may send a CSI report based on which the UE 702 activates one of the first reference signal or the second reference signal of the SCell 706. Further, 816 may be performed by CSI component 1544.

At 818, the UE may activate the SCell based on one or more reference signals including at least one of the received first reference signal and/or second reference signal (i.e., as at 726). The UE may activate the SCell based on one or more reference signals (including at least one of the first reference signal or the second reference signal) upon identifying receipt of the second reference signal. The UE may receive the activation indication in time slot n and may activate the SCell no later than in time slot n+k, where K is determined based on at least one of: a time period between receiving an activation indication from a serving cell and sending an Acknowledgement (ACK) of the activation indication to the serving cell, an SCell activation time, and a delay uncertainty in acquiring one or more first available CSI reporting resources. For example, the UE may receive the activation indication in slot n and may be no later than in slot The SCell is activated. May be based on including at least one of the first reference signal or the second reference signalOne or more reference signals of an item to determine T _{activation_time} . In one aspect, the SCell activation time may be between transmission of the ACK of the activation indication and a second duration after receiving the at least one temporary reference signal. In another aspect, the SCell activation time may be between transmission of an ACK of the activation indication and a second duration after receiving a last one of the one or more reference signals based on which the UE activates the SCell. In another aspect, the SCell activation time may be between transmission of an ACK of the activation indication and a second duration after receiving two or four reference signals including one of the first reference signal or the second reference signal. The UE may simultaneously activate a plurality of scells based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, whichever is received earliest from the plurality of scells. The UE may activate the plurality of scells based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, based on receipt within an earliest activation time for the plurality of scells. The UE may activate the plurality of scells based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, based on latest reception from the plurality of scells. For example, at 726, the UE 702 may activate the SCell 706 based on one or more reference signals including at least one of the received first reference signal and/or second reference signal. Further, 818 may be performed by SCell activation component 1540.

Fig. 9 is a flow chart 900 of a method of wireless communication. The method may be performed by a UE (e.g., UE 104, 702; apparatus 1502). The UE may receive SCell activation commands or indications from one or more active serving cells (e.g., serving cells). One or more temporary RSs may be provided to accelerate the SCell activation procedure, and the UE may accelerate the SCell activation procedure using the one or more temporary RSs received from the SCell. The UE may activate the SCell no later than in time slot n+k, where K may be determined based at least in part on the SCell activation time.

At 902, the UE may receive an activation indication from a serving cell to activate an SCell. The activation indication may be received via one of a MAC-CE, DCI or RRC signal. The activation indication may indicate that multiple scells are activated simultaneously, the multiple scells including a first SCell and a second SCell. For example, at 710, the UE 702 may receive an activation indication from the serving cell 704 to activate the SCell 706. Further, 902 may be performed by SCell activation component 1540.

At 908, the UE may receive a first reference signal from the SCell, the first reference signal comprising at least one temporary reference signal (i.e., as at 716). The first reference signal may be a temporary RS including an aperiodic tracking RS indicated by a MAC-CE or DCI or a periodic tracking RS indicated by an RRC signal. Here, the first reference signal may be received from an active serving cell. For example, at 716, the UE 702 may receive a first reference signal from the SCell 706, the first reference signal comprising at least one temporary reference signal. Further, 908 may be performed by SCell activation component 1540.

At 912, the UE may identify whether a second reference signal is received after processing the activation indication and before expiration of the SCell activation time (i.e., as at 720). For example, at 720, the UE 702 may identify whether a second reference signal is received after processing the activation indication and before expiration of the SCell activation time. Further, 912 may be performed by SCell activation component 1540.

At 918, the UE may activate the SCell based on one or more reference signals including at least one of the received first reference signal and/or second reference signal (i.e., as at 726). The UE may activate the SCell based on one or more reference signals (including at least one of the first reference signal or the second reference signal) upon identifying receipt of the second reference signal. The UE may receive the activation indication in time slot n and may activate the SCell no later than in time slot n+k, where K is determined based on at least one of: upon receiving an activation indication from a serving cellThe serving cell transmits an Acknowledgement (ACK) of the activation indication, a SCell activation time, and a delay uncertainty in acquiring one or more first available CSI report resources. For example, the UE may receive the activation indication in slot n and may be no later than in slot The SCell is activated. T may be determined based on one or more reference signals including at least one of the first reference signal or the second reference signal _{activation_time} . In one aspect, the SCell activation time may be between transmission of an ACK of the activation indication and a second duration after receiving the at least one temporary reference signal. In another aspect, the SCell activation time may be between transmission of an ACK of the activation indication and a second duration after receiving a last one of the one or more reference signals based on which the UE activates the SCell. In another aspect, the SCell activation time may be between transmission of an ACK of the activation indication and a second duration after receiving two or four reference signals including one of the first reference signal or the second reference signal. The UE may simultaneously activate a plurality of scells based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, whichever is received earliest from the plurality of scells. The UE may activate the plurality of scells based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, based on receipt within an earliest activation time for the plurality of scells. The UE may activate the plurality of scells based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, based on latest reception from the plurality of scells. For example, at 726, the UE 702 may activate SCe based on one or more reference signals including at least one of the received first reference signal and/or second reference signal And ll 706. Further, 918 can be performed by SCell activation component 1540.

Fig. 10 shows an example of SCell activation 1000 for wireless communication. Examples of SCell activation 1000 include SCell 1010 and PCell1020. An example of SCell activation 1000 for wireless communication shows that SCell 1010 may transmit a first temporary RS 1018, a second temporary RS1019, and SSB 1012. The first temporary RS 1018 may be an aperiodic tracking RS triggered by DCI or MAC-CE, and the second temporary RS1019 may be a periodic tracking RS triggered by RRC signals. The UE may generate and send an ACK 1024 to PCell1020. For scells in the unlicensed band (or shared spectrum), one or more RSs 1018 and 1019 (SSBs or temporary RSs including periodically or aperiodically tracking RSs) may not be transmitted due to LBT failure. That is, the UE may determine whether the SCell activation indication 1022 is implicitly canceled based on transmission of the temporary RS including the first temporary RS 1018 or the second temporary RS 1019. The UE may perform a clear channel assessment to determine whether a channel measurement of received power is greater than a threshold. If the UE determines that the channel measurement of the received power is greater than the threshold, the UE may determine a T for based on one or more RSs 1018 and 1019 _{activation_time} Is actually used for data transmission, and a temporary RS including the first or second temporary RS 1018 or 1019 is not transmitted as indicated by the SCell activation indication 1022.

Aspects of the present disclosure are not limited to scells 1010 in an unlicensed band (or shared spectrum) upon LBT failure. In some aspects, the same procedure may be applied when/if one or more RSs 1018 and 1019 are not transmitted due to overlapping UL transmissions or DL receptions, cancellation/preemption of DL reception of another signal/channel. That is, the UE may receive DCI or MAC-CE indicating UL transmission, DL reception, cancellation, or preemption, which may indicate that the UE does not use one or more RSs 1018 and 1019 that may not be transmitted as indicated by the SCell activation indication.

Fig. 11 illustrates an example of SCell activation 1100 for wireless communication. Examples of SCell activation 1100 include SCell 1110 and PCell1120. An example of SCell activation 1100 for wireless communication shows that SCell 1110 may transmit a first temporary RS 1118, a second temporary RS 1118Temporary RS1119 and SSB 1112. The first and second temporary RSs 1118 and 1119 may be aperiodic tracking RSs triggered by DCI or MAC-CE. The UE may generate and send an ACK 1124 to PCell1120. The network may update the temporary RS resources and eventually cancel/preempt the temporary RS. For such a case, the network or BS may indicate a new temporary RS resource through DCI or MAC-CE. That is, the UE may receive a new SCell activation indication 1122, the new SCell activation indication 1122 indicating that the UE uses a new temporary RS1119 to activate SCell 1110. In response to determining that the RS resources are updated from the first temporary RS 1118 to the second temporary RS1119, the ue may determine that the original SCell activation indication is no longer valid and the first temporary RS 1118 may not transmit as indicated in the original SCell activation indication. Thus, for T _{activation_time} May be based on new RS resources associated with the second temporary RS 1119. The network may indicate cancellation/preemption via DCI or MAC-CE. The DCI may be DCI transmitted to trigger cancellation or offset of the temporary RS or may be scheduling DCI for UL/DL Tx/Rx overlapping with the initial a-TRS. The MAC-CE may trigger cancellation or offset of the temporary RS directly or may be the same as the MAC-CE used to trigger another temporary RS on that carrier or other carriers. The MAC-CE may also be used to trigger SCell activation on other carriers.

In some aspects, an SCell to be activated for wideband operation in an unlicensed band (or shared spectrum) may include multiple LBT subbands (e.g., 20MHz each), and the temporary RS and/or the periodic tracking RS may be subject to LBT per multiple LBT subbands. That is, partial transmission of the temporary RS and/or the periodic tracking RS for activation of the SCell in the frequency domain due to LBT failure in at least a portion of the LBT subband may not be considered as valid transmission of the temporary RS for the purpose of the activation procedure.

Fig. 12 shows a call flow diagram 1200 of wireless communication. The call flow diagram 1200 may include a UE 1202, a serving cell 1204, and an SCell 1206 to be activated by the UE 1202. The UE 1202 may receive SCell activation commands or indications from one or more active serving cells (e.g., serving cell 1204). One or more temporary RSs may be provided to accelerate the SCell activation procedure, and the UE 1202 may accelerate the SCell activation procedure using the one or more temporary RSs received from the SCell 1206. The UE 1202 may activate the SCell 1206 in n+k no later than the slot and K may be determined based at least in part on the SCell activation time.

At 1210, the UE 1202 may receive an activation indication from the serving cell 1204 for activating the SCell 1206. The activation indication may be received via one of a MAC-CE, DCI or RRC signal. The activation indication may indicate that multiple scells 1206 are activated simultaneously, the multiple scells 1206 comprising a first SCell and a second SCell. The first SCell and the second SCell may be in the same frequency band, in adjacent carriers in the same frequency band, or in a frequency range. At 1211, the serving cell 1204 may configure the SCell 1206 to transmit one or more RSs comprising the first reference signal and/or the second reference signal.

At 1212, UE 1202 may send an ACK to serving cell 1204 for receiving an activation indication, wherein the activation indication is processed for a first duration after sending the ACK to serving cell 1204.

At 1214, UE 1202 may process the activation indication received from serving cell 1204. The UE 1202 may receive the first reference signal and/or the second reference signal based on the processed activation indication.

At 1216, the UE 1202 may receive a first reference signal from the SCell 1206, the first reference signal comprising at least one temporary reference signal, as indicated by the activation indication at 1210. The first reference signal may be a temporary RS including an aperiodic tracking RS indicated by a MAC-CE or DCI or a periodic tracking RS indicated by an RRC signal. Here, the first reference signal may be received from the active serving cell 1204.

At 1218, the UE 1202 may receive a new activation indication from the serving cell 1204 for activating the SCell 1206. The activation indication may be received via one of a MAC-CE or DCI. The activation indication may indicate that multiple scells 1206 are activated simultaneously, the multiple scells 1206 comprising a first SCell and a second SCell. The first SCell and the second SCell may be in the same frequency band, in adjacent carriers in the same frequency band, or in a frequency range. At 1219, the serving cell 1204 may configure the SCell 1206 to transmit one or more RSs comprising the first reference signal and/or the second reference signal.

At 1220, the UE 1202 may send an ACK to the serving cell 1204 for receiving a new activation indication, wherein the activation indication is processed for a first duration after sending the ACK to the serving cell 1204.

At 1222, UE 1202 may perform a clear channel assessment to determine whether the channel measurement is greater than a threshold.

At 1224, the UE 1202 may identify whether the first reference signal is transmitted as indicated by the activation indication at 1210. In response to determining that the channel measurement is greater than the threshold at 1222, the UE 1202 may identify that the first reference signal was not transmitted as indicated by the activation indication. The UE 1202 may also receive an instruction to cancel transmission of the first reference signal from the serving cell, wherein the UE identifies that the first reference signal is not transmitted in response to receiving the instruction to cancel the transmitted first reference signal, the instruction to cancel the activation indication for the SCell based on the first reference signal being indicated by one of MAC-CE or DCI. The SCell may include a plurality of subbands and the UE 1202 may perform a clear channel assessment to determine whether a channel measurement is greater than a threshold for at least one of the plurality of subbands and upon determining that the channel measurement for the at least one of the plurality of subbands is greater than the threshold, identify that the first reference signal is not being transmitted as indicated.

At 1226, the UE 1202 may receive a second reference signal from the SCell 1206, the first reference signal comprising at least one temporary reference signal as indicated by the new activation indication at 1218. The first reference signal may be a temporary RS including an aperiodic tracking RS indicated by a MAC-CE or DCI or a periodic tracking RS indicated by an RRC signal. Here, the first reference signal may be received from the active serving cell 1204.

At 1228, the UE 1202 may generate a CSI report based on which the UE 1202 activates one of the first reference signal or the second reference signal of the SCell 1206.

At 1230, the UE 1202 may transmit a CSI report based on which the UE 1202 activates one of the first reference signal or the second reference signal of the SCell 1206.

At 1232, the UE 1202 may activate the SCell 1206 based on one or more reference signals comprising at least one of the received first reference signal and/or second reference signal. The UE 1202 may activate SCell based on one or more reference signals including the first reference signal or the second reference signal upon identifying that the first reference signal is not being transmitted as indicated. The UE 1202 may receive the activation indication in time slot n and may activate SCell 1206 no later than in time slot n+k, where K is determined based on at least one of: a time period between receiving an activation indication from a serving cell and sending an Acknowledgement (ACK) of the activation indication to the serving cell, an SCell activation time, and a delay uncertainty in acquiring one or more first available CSI reporting resources. For example, UE 1202 may receive the activation indication in slot n and may be no later than in slot The SCell 1206.T (T) _{activation_time} May be an SCell activation time and determined based on one or more reference signals including at least one of the first reference signal or the second reference signal. In one aspect, the SCell activation time may be between transmission of an ACK of the activation indication and a second duration after receiving the second reference signal. In another aspect, the SCell activation time may be between transmission of the ACK of the activation indication and a second duration after receiving the second reference signal.

The UE 1202 may simultaneously activate the plurality of scells 1206 based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, whichever is received earliest from the plurality of scells 1206. The UE 1202 may activate the plurality of scells 1206 based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, whichever is received within an earliest activation time for the plurality of scells 1206. The UE 1202 may activate the plurality of scells 1206 based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, whichever is received latest from the plurality of scells 1206.

Fig. 13 is a flow chart 1300 of a method of wireless communication. The method may be performed by a UE (e.g., UE 104, 1202; apparatus 1502). The UE may receive SCell activation commands or indications from one or more active serving cells (e.g., serving cells). One or more temporary RSs may be provided to accelerate the SCell activation procedure, and the UE may accelerate the SCell activation procedure using the one or more temporary RSs received from the SCell. The UE may activate the SCell no later than in time slot n+k, where K may be determined based at least in part on the SCell activation time.

At 1302, the UE 1302 may receive an activation indication from a serving cell to activate an SCell. The activation indication may be received via one of a MAC-CE, DCI or RRC signal. The activation indication may indicate that multiple scells are activated simultaneously, the multiple scells including a first SCell and a second SCell. The first SCell and the second SCell may be in the same frequency band, in adjacent carriers in the same frequency band, or in a frequency range. For example, at 1210, the UE 1202 may receive an activation indication from the serving cell 1204 for activating the SCell 1206. Further, 1302 can be performed by SCell activation component 1540.

At 1304, the UE may send an ACK to the serving cell for receipt of an activation indication, wherein the activation indication is processed for a first duration after sending the ACK to the serving cell. For example, at 1212, UE 1202 may send an ACK to serving cell 1204 for receipt of an activation indication, where the activation indication is processed for a first duration after sending the ACK to serving cell 1204. Further, 1304 can be performed by ACK component 1542.

At 1306, the UE may process the activation indication received from the serving cell. The UE may receive the first reference signal and/or the second reference signal based on the processed activation indication. For example, at 1214, UE 1202 may process the activation indication received from serving cell 1204. Further, 1306 may be performed by SCell activation component 1540.

At 1308, the UE may receive a first reference signal from the SCell, the first reference signal comprising at least one temporary reference signal, as indicated by the activation indication at 1302. The first reference signal may be a temporary RS including an aperiodic tracking RS indicated by MAC-CE or DCI or a periodic tracking RS indicated by an RRC signal. Here, the first reference signal may be received from an active serving cell. For example, at 1216, the UE 1202 may receive a first reference signal from the SCell 1206, the first reference signal including at least one temporary reference signal, as indicated by the activation indication at 1210. Further, 1308 may be performed by SCell activation component 1540.

At 1310, the UE may receive a new activation indication from the serving cell for activating the SCell (i.e., as at 1118). The activation indication may be received via one of a MAC-CE or DCI. The activation indication may indicate that multiple scells are activated simultaneously, the multiple scells including a first SCell and a second SCell. The first SCell and the second SCell may be in the same frequency band, in adjacent carriers in the same frequency band, or in a frequency range. For example, at 1218, the UE 1202 may receive a new activation indication from the serving cell 1204 to activate the SCell 1206. Further, 1310 may be performed by SCell activation component 1540.

At 1312, the UE may send an ACK to the serving cell for receipt of a new activation indication, wherein the activation indication is processed for a first duration after sending the ACK to the serving cell. For example, at 1220, UE 1202 may send an ACK to serving cell 1204 for receiving a new activation indication, where the activation indication is processed for a first duration after sending the ACK to serving cell 1204. Further, 1312 may be performed by ACK component 1542.

At 1314, the UE may perform a clear channel assessment to determine whether the channel measurement is greater than a threshold. For example, at 1222, UE 1202 may perform a clear channel assessment to determine whether the channel measurement is greater than a threshold. Further, 1314 may be performed by LBT component 1546.

At 1316, the UE may identify whether the first reference signal is transmitted as indicated by the activation indication at 1302. In response to determining that the channel measurement is greater than the threshold at 1314, the UE may identify that the first reference signal is not being transmitted as indicated by the activation indication. The UE may also receive an instruction to cancel transmission of the first reference signal from the serving cell, wherein the UE identifies that the first reference signal is not transmitted in response to receiving the instruction to cancel the transmitted first reference signal, the instruction to cancel the activation indication for the SCell based on the first reference signal being indicated by one of MAC-CE or DCI. The SCell may include a plurality of subbands and the UE may perform a clear channel assessment to determine whether the channel measurement is greater than a threshold for at least one of the plurality of subbands and upon determining that the channel measurement for the at least one of the plurality of subbands is greater than the threshold, identify that the first reference signal is not being transmitted as indicated. For example, at 1224, the UE 1202 may identify whether the first reference signal is transmitted as indicated by the activation indication at 1210. Further, 1316 may be performed by SCell activation component 1540.

At 1318, the UE may receive a second reference signal from SCell 1206, the second reference signal comprising at least one temporary reference signal, as indicated by the new activation indication received at 1312. The second reference signal may be a temporary RS including an aperiodic tracking RS indicated through MAC-CE or DCI. Here, the second reference signal may be received from an active serving cell. For example, at 1226, the UE 1202 may receive a second reference signal from the SCell 1206, the first reference signal comprising at least one temporary reference signal, as indicated by the new activation indication at 1218. Further, 1318 may be performed by SCell activation component 1540.

At 1320, the UE may generate a CSI report based on which the UE activates one of the first reference signal or the second reference signal of the SCell. For example, at 1228, the UE 1202 may generate a CSI report based on which the UE 1202 activates one of the first reference signal or the second reference signal of the SCell 1206. Further, 1320 may be performed by CSI component 1544.

At 1322, the UE may send a CSI report based on which the UE activates one of the first reference signal or the second reference signal of the SCell. For example, at 1230, the UE may transmit a CSI report based on which the UE 1202 activates one of the first reference signal or the second reference signal of the SCell 1206. Further, 1322 may be performed by CSI component 1544.

At 1324, the UE may activate the SCell based on one or more reference signals comprising at least one of the received first reference signal and/or second reference signal. The UE may activate the SCell based on one or more reference signals including the first reference signal or the second reference signal upon identifying that the first reference signal is transmitted as indicated. The UE may receive the activation indication in time slot n and may activate the SCell no later than in time slot n+k, where K is determined based on at least one of: a time period between receiving an activation indication from a serving cell and sending an Acknowledgement (ACK) of the activation indication to the serving cell, an SCell activation time, and a delay uncertainty in acquiring one or more first available CSI reporting resources. For example, the UE may receive the activation indication in slot n and may be no later than in slotThe SCell is activated. T (T) _{activation_time} May be an SCell activation time and determined based on one or more reference signals including at least one of the first reference signal or the second reference signal. In one aspect, the SCell activation time may be between transmission of an ACK of the activation indication and a second duration after receiving the second reference signal. In another aspect, the SCell activation time may be between transmission of the ACK of the activation indication and a second duration after receiving the second reference signal. The UE may simultaneously activate multiple scells based on one or more reference signals including at least one temporary reference signal including an aperiodic tracking reference signal or a periodic tracking reference signal to The earliest received from multiple scells. The UE may activate the plurality of scells based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, based on receipt within an earliest activation time for the plurality of scells. The UE may activate the plurality of scells based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, based on a latest reception from the plurality of scells. For example, at 1232, the UE 1202 may activate the SCell1206 based on one or more reference signals including at least one of the received first reference signal and/or second reference signal. Further, 1324 may be performed by SCell activation component 1540.

Fig. 14 is a flow chart 1400 of a method of wireless communication. The method may be performed by a UE (e.g., UE 104, 1202; apparatus 1502). The UE may receive SCell activation commands or indications from one or more active serving cells (e.g., serving cells). One or more temporary RSs may be provided to accelerate the SCell activation procedure, and the UE may accelerate the SCell activation procedure using the one or more temporary RSs received from the SCell. The UE may activate the SCell no later than in time slot n+k, where K may be determined based at least in part on the SCell activation time.

At 1402, the UE may receive an activation indication from a serving cell for activating an SCell. The activation indication may be received via one of a MAC-CE, DCI or RRC signal. The activation indication may indicate that multiple scells are activated simultaneously, the multiple scells including a first SCell and a second SCell. The first SCell and the second SCell may be in the same frequency band, in adjacent carriers in the same frequency band, or in a frequency range. For example, at 1210, the UE 1202 may receive an activation indication from the serving cell 1204 for activating the SCell 1206. Further, 1402 can be performed by SCell activation component 1540.

At 1416, the UE may identify whether the first reference signal is transmitted as indicated by the activation indication at 1402. In response to determining that the channel measurement is greater than the threshold, the UE may identify that the first reference signal is not being transmitted as indicated by the activation indication. The UE may also receive an instruction to cancel transmission of the first reference signal from the serving cell, wherein the UE identifies that the first reference signal is not transmitted in response to receiving the instruction to cancel the transmitted first reference signal, the instruction to cancel the activation indication for the SCell based on the first reference signal being indicated by one of MAC-CE or DCI. The SCell may include a plurality of subbands and the UE may perform a clear channel assessment to determine whether the channel measurement is greater than a threshold for at least one of the plurality of subbands and, upon determining that the channel measurement for the at least one of the plurality of subbands is greater than the threshold, determine that the first reference signal is not transmitted as indicated. For example, at 1224, the UE 1202 may identify whether the first reference signal is transmitted as indicated by the activation indication at 1210. Further, 1416 may be performed by SCell activation component 1540.

At 1424, the UE may activate the SCell based on one or more reference signals including at least one of the received first reference signal and/or second reference signal. The UE may activate the SCell based on one or more reference signals including the first reference signal or the second reference signal upon identifying that the first reference signal is transmitted as indicated. The UE may receive the activation indication in time slot n and may activate the SCell no later than in time slot n+k, where K is determined based on at least one of: a time period between receiving an activation indication from a serving cell and sending an Acknowledgement (ACK) of the activation indication to the serving cell, an SCell activation time, and a delay uncertainty in acquiring one or more first available CSI reporting resources. For example, the UE may receive the activation indication in slot n and may be no later than in slotThe SCell is activated. T (T) _{activation_time} May be an SCell activation time and determined based on one or more reference signals including at least one of the first reference signal or the second reference signal. In one aspect, SCell activationThe time may be between transmission of the ACK of the activation indication and a second duration after receiving the second reference signal. In another aspect, the SCell activation time may be between transmission of the ACK of the activation indication and a second duration after receiving the second reference signal. The UE may simultaneously activate a plurality of scells based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, whichever is received earliest from the plurality of scells. The UE may activate the plurality of scells based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, based on receipt within an earliest activation time for the plurality of scells. The UE may activate the plurality of scells based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, based on a latest reception from the plurality of scells. For example, at 1232, the UE 1202 may activate the SCell 1206 based on one or more reference signals including at least one of the received first reference signal and/or second reference signal. Furthermore, 1424 may be performed by SCell activation component 1540.

Fig. 15 is a schematic diagram 1500 illustrating an example of a hardware implementation for an apparatus 1502. The apparatus 1502 may be a UE, a component of a UE, or may implement UE functionality. In some aspects, the apparatus 1502 may include a cellular baseband processor 1504 (also referred to as a modem) coupled to a cellular RF transceiver 1522. In some aspects, the apparatus 1502 may also include one or more Subscriber Identity Module (SIM) cards 1520, an application processor 1506 coupled to a Secure Digital (SD) card 1508 and a screen 1510, a bluetooth module 1512, a Wireless Local Area Network (WLAN) module 1514, a Global Positioning System (GPS) module 1516, or a power supply 1518. The cellular baseband processor 1504 communicates with the UE 104 and/or BS 102/180 via a cellular RF transceiver 1522. The cellular baseband processor 1504 may include a computer readable medium/memory. The computer readable medium/memory may be non-transitory. The cellular baseband processor 1504 is responsible for general processing, including the execution of software stored on the computer-readable medium/memory. The software, when executed by the cellular baseband processor 1504, causes the cellular baseband processor 1504 to perform the various functions described supra. The computer readable medium/memory can also be used for storing data that is manipulated by the cellular baseband processor 1504 when executing software. The cellular baseband processor 1504 also includes a receive component 1530, a communication manager 1532, and a transmit component 1534. The communication manager 1532 includes one or more of the illustrated components. Components within the communication manager 1532 may be stored in a computer readable medium/memory and/or configured as hardware within the cellular baseband processor 1504. The cellular baseband processor 1504 may be a component of the UE 350 and may include at least one of a TX processor 368, an RX processor 356, and a controller/processor 359, and/or a memory 360. In one configuration, the apparatus 1502 may be a modem chip and include only the baseband processor 1504, while in another configuration, the apparatus 1502 may be an entire UE (see, e.g., 350 of fig. 3) and include additional modules of the apparatus 1502.

The communication manager 1532 includes an SCell activation component 1540, the SCell activation component 1540 configured to: the method includes receiving an activation indication from a serving cell for activating an SCell, processing the received activation indication, receiving a first reference signal and/or a second reference signal, identifying whether the second reference signal is received after processing the activation indication and before expiration of an SCell activation time, identifying whether the first reference signal is transmitted as indicated by the activation indication, and activating the SCell based on one or more reference signals including at least one of the received first reference signal and/or second reference signal, e.g., as described in connection with 802, 806, 808, 810, 812, 818, 902, 908, 912, 918, 1302, 1306, 1308, 1310, 1316, 1318, 1324, 1402, 1416, and 1424. Communication manager 1532 also includes ACK component 1542, ACK component 1542 configured to: an ACK is sent to the serving cell for receipt of the activation indication, e.g., as described in connection with 804, 1304, and 1312. The communication manager 1532 further includes a CSI component 1544, the CSI component 1544 configured to generate a CSI report based on which the UE activates one of the first reference signal or the second reference signal of the SCell, and to transmit CSI, e.g., as described in connection with 814, 816, 1320, and 1322. The communication manager 1532 also includes an LBT component 1546, the LBT component 1546 configured to perform a clear channel assessment to determine if the channel measurement is greater than a threshold, e.g., as described in connection with 1314.

The apparatus may include additional components for each of the blocks executing the algorithms in the flowcharts of fig. 7, 8, 9, 12, 13 and 14. Thus, each block in the flowcharts of fig. 7, 8, 9, 12, 13, and 14 may be performed by components, and an apparatus may include one or more of these components. The components may be one or more hardware components specifically configured to perform the recited processes/algorithms, may be implemented by a processor configured to perform the recited processes/algorithms, may be stored within a computer-readable medium for implementation by a processor, or some combination thereof.

As shown, the apparatus 1502 may include various components configured for various functions. In one configuration, the apparatus 1502 (and in particular the cellular baseband processor 1504) includes: means for receiving an activation indication for an SCell from a serving cell; means for receiving a first reference signal from an SCell, the first reference signal comprising at least one temporary reference signal; means for identifying whether a second reference signal is received after processing the activation indication and before expiration of the SCell activation time; and means for activating the SCell based on one or more reference signals comprising at least one of the first reference signal or the second reference signal upon identifying receipt of the second reference signal. The apparatus 1502 includes: means for sending an ACK to the serving cell for receiving an activation indication, wherein the activation indication is processed for a first duration after sending the ACK to the serving cell; and means for transmitting a CSI report based on which the UE activates one of the first reference signal or the second reference signal of the SCell. The apparatus 1502 includes: the apparatus includes means for identifying whether to receive a second reference signal from an active serving cell. The apparatus 1502 includes: means for receiving an activation indication for the SCell from the serving cell based on the first reference signal, the activation indication indicating transmission of the first reference signal for activating the SCell; a transmitting unit for identifying whether the first reference signal is transmitted as indicated; and means for activating the SCell based on one or more reference signals comprising the first reference signal or the second reference signal upon identifying that the first reference signal is transmitted as indicated. The apparatus 1502 includes means for sending an ACK to a serving cell for receiving an activation indication, wherein the activation indication is processed for a first duration after sending the ACK to the serving cell; and means for receiving a new activation indication indicating transmission of a second reference signal for activating the SCell. The apparatus 1502 includes: means for performing a clear channel assessment to determine whether the channel measurement is greater than a threshold for at least one of the plurality of subbands; and upon determining that the channel measurement for at least one of the plurality of subbands is greater than a threshold, identifying that the first reference signal is not being transmitted as indicated. The elements may be one or more of the components of apparatus 1502 configured to perform the functions recited by the elements. As described above, the apparatus 1502 may include a TX processor 368, an RX processor 356, and a controller/processor 359. Thus, in one configuration, the elements may be TX processor 368, RX processor 356, and controller/processor 359 configured to perform the functions recited by the preceding claims.

The UE may receive an activation indication for the SCell from the serving cell, receive a first reference signal from the SCell, the first reference signal including at least one temporary reference signal, identify whether a second reference signal is received after processing the activation indication and before expiration of an SCell activation time, and, upon identifying that the second reference signal is received, activate the SCell based on one or more reference signals including at least one of the first reference signal or the second reference signal.

The UE may send an ACK to the serving cell for receiving an activation indication, wherein the activation indication is processed for a first duration after sending the ACK to the serving cell. The UE may send a CSI report based on which the UE activates one of the first reference signal or the second reference signal of the SCell.

The UE may activate the SCell no later than in time slot n+k, where K may be determined based at least in part on the SCell activation time. In one aspect, the activation indication may be received via one of a MAC-CE or DCI, and the at least one temporary reference signal includes an aperiodic tracking reference signal, and the activation indication indicates an aperiodic tracking reference signal transmitted by the SCell. The SCell activation time may be an SCell activation time between transmission of the ACK of the activation indication and a second duration after receiving the at least one temporary reference signal.

In another aspect, the activation indication may be received via RRC signaling and the at least one temporary reference signal includes a periodic tracking reference signal, and the activation indication indicates the periodic tracking reference signal transmitted by the SCell. The SCell activation time may be an SCell activation time between transmission of an ACK of the activation indication and a second duration after receiving a last one of the one or more reference signals based on which the UE activates the SCell. The activation indication may indicate that a plurality of scells are activated simultaneously, and the plurality of scells may be in the same frequency band, in adjacent carriers in the same frequency band, or in a frequency range.

The UE may receive an activation indication for the SCell from the serving cell based on the first reference signal, the activation indication indicating transmission of the first reference signal for activating the SCell, identify whether the first reference signal is transmitted as indicated, and activate the SCell based on one or more reference signals including the first reference signal or the second reference signal when the first reference signal is identified as being transmitted as indicated. The UE may send an ACK to the serving cell for receiving the activation indication, wherein the activation indication is processed for a first duration after sending the ACK to the serving cell.

The first reference signal may include at least one of a periodic tracking reference signal or an aperiodic tracking reference signal. The UE may identify whether the first reference signal is transmitted as indicated by performing a clear channel assessment to determine whether the channel measurement is greater than a threshold; and in response to determining that the channel measurement is greater than the threshold, identifying that the first reference signal is not being transmitted as indicated by the activation indication.

The UE may receive an instruction to cancel transmission of the first reference signal from the serving cell, wherein the UE identifies that the first reference signal is not transmitted in response to receiving the instruction to cancel the transmitted first reference signal, and wherein the instruction to cancel the activation indication for the SCell based on the first reference signal is indicated by one of MAC-CE or DCI.

The UE may receive a second reference signal from the SCell when it is identified that the first reference signal is not being transmitted as indicated, and activate the SCell based on the second reference signal received from the SCell when it is identified that the first reference signal is not being transmitted as indicated. The SCell activation time may be an SCell activation time between transmission of the ACK of the activation indication and a second duration after receiving the second reference signal.

The UE may receive a new activation indication indicating transmission of a second reference signal for activating the SCell, wherein upon receiving the new activation indication, the UE identifies that the first reference signal is not transmitted as indicated.

It is to be understood that the specific order or hierarchy of blocks in the processes/flow diagrams disclosed herein is an illustration of example approaches. It will be appreciated that the particular order or hierarchy of blocks in the process/flow diagram may be rearranged based on design preferences. In addition, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to a singular element is not intended to mean "one and only one" unless specifically so stated, but rather "one or more". Terms such as "if", "when …" and "when …" should be interpreted to mean "under … conditions" rather than implying an immediate time relationship or reaction. That is, these phrases (e.g., "when …") do not imply an immediate action in response to the occurrence of the action or at the occurrence of the action, but rather simply mean that the action will occur if a certain condition is met, but do not require a specific or immediate time limit for the action to occur. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration. Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects. The term "some" refers to one or more unless specifically stated otherwise. Combinations such as "at least one of A, B or C", "one or more of A, B or C", "at least one of A, B and C", "one or more of A, B and C", and "A, B, C or any combination thereof", include any combination of A, B and/or C, and may include multiples of a, multiples of B, or multiples of C. In particular, 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 a alone, B alone, C, A and B, A and C, B and C or a and B and C, wherein any such combination may comprise one or more members of A, B or C. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Furthermore, the disclosures herein are not intended to be dedicated to the public, regardless of whether such disclosures are explicitly recited in the claims. The words "module," means, "" element, "" device, "etc., may not be substitutes for the word" unit. Thus, no claim element is to be construed as a functional unit unless the element is explicitly recited using the element for … ….

The following aspects are merely illustrative and may be combined with other aspects or teachings described herein, but are not limited thereto.

Aspect 1 is a method of wireless communication for a UE, the method comprising: receiving an activation indication for the SCell from the serving cell; receiving a first reference signal from the SCell, the first reference signal comprising at least one temporary reference signal; identifying whether a second reference signal is received after processing the activation indication and before expiration of the SCell activation time; and upon identifying receipt of the second reference signal, activating the SCell based on one or more reference signals including at least one of the first reference signal or the second reference signal.

Aspect 2 is the method of aspect 1, further comprising: an ACK is sent to the serving cell for receipt of an activation indication, wherein the activation indication is processed for a first duration after sending the ACK to the serving cell.

Aspect 3 is the method of any of aspects 1 and 2, further comprising: the CSI report of one of the first reference signal or the second reference signal on which the UE activates the SCell is transmitted.

Aspect 4 is the method according to any of aspects 1 to 3, wherein the activation indication is received via one of a MAC-CE or DCI.

Aspect 5 is the method of aspect 4, wherein the at least one temporary reference signal comprises an aperiodic tracking reference signal, and the activation indication indicates the aperiodic tracking reference signal transmitted by the SCell.

Aspect 6 is the method of aspect 5, wherein the UE is not later than in the slotAn SCell, wherein the activation indication is received in slot n, T _HARQ Is an acknowledgement of the reception of an activation indication from and the transmission of an activation indication to a serving cellTime period between (ACKs), T _{activation_time} SCell activation time between transmission of ACK of activation indication and second duration after receiving at least one temporary reference signal, and T _{CSI_reporting} Is the delay uncertainty in acquiring one or more first available CSI reporting resources.

Aspect 7 is the method of any of aspects 1 to 3, wherein the activation indication is received via RRC signaling.

Aspect 8 is the method of aspect 7, wherein the at least one temporary reference signal comprises a periodic tracking reference signal, and the activation indication indicates the periodic tracking reference signal transmitted by the SCell.

Aspect 9 is the method of aspect 8, wherein the UE is not later than in the slot An SCell, wherein the activation indication is received in slot n, T _HARQ Is the period of time between receiving an activation indication from the serving cell and sending an ACK for the activation indication to the serving cell, T _{activation_time} Is an SCell activation time between transmission of an ACK of the activation indication and a second duration after receiving a last one of one or more reference signals based on which the UE activates the SCell, and T _{CSI_reporting} Is the delay uncertainty in acquiring one or more first available CSI reporting resources.

Aspect 10 is the method according to any of aspects 1 to 9, wherein the first reference signal is received from an active serving cell, and wherein the UE identifies whether the second reference signal is received from the active serving cell.

Aspect 11 is the method according to any of aspects 1 to 10, wherein the first reference signal and the second reference signal are assumed to be quasi co-located with each other.

Aspect 12 is the method according to any of aspects 1 to 11, wherein the activation indication indicates that multiple scells are activated simultaneously, the multiple scells comprising a first SCell and a second SCell.

Aspect 13 is the method of aspect 12, wherein the first SCell and the second SCell are in the same frequency band, in adjacent carriers in the same frequency band, or in a frequency range.

Aspect 14 is the method according to any of aspects 12 and 13, wherein the UE activates the plurality of scells based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, whichever is received earliest from the plurality of scells.

Aspect 15 is the method according to any of aspects 12 to 14, wherein the UE activates the plurality of scells based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, whichever is received within an earliest activation time for the plurality of scells.

Aspect 16 is the method according to any of aspects 12 to 15, wherein the UE activates the plurality of scells based on one or more reference signals comprising at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, whichever is received last from the plurality of scells.

Aspect 17 is the method of any of aspects 1 to 5, 7, 8, 10 to 16, wherein the UE is not later than in a slot An SCell, wherein the activation indication is received in slot n, T _HARQ Is the period of time between receiving an activation indication from the serving cell and sending an ACK for the activation indication to the serving cell, T _{activation_time} SCell activation time between transmission of ACK of activation indication and second duration after receiving two reference signals including one of first reference signal or second reference signal, and T _{CSI_reporting} Is the delay uncertainty in acquiring one or more first available CSI reporting resources.

Aspect 18 is the method of any of aspects 1 to 5, 7, 8, 10 to 16, wherein the UE is not later than in a slotAn SCell, wherein the activation indication is received in slot n, T _HARQ Is the period of time between receiving an activation indication from the serving cell and sending an ACK for the activation indication to the serving cell, T _{activation_time} SCell activation time between transmission of ACK of activation indication and second duration after receiving four reference signals including one of first reference signal or second reference signal, and T _{CSI_reporting} Is the delay uncertainty in acquiring one or more first available CSI reporting resources.

Aspect 19 is an apparatus for wireless communication, the apparatus comprising at least one processor coupled to a memory and configured to implement the method as recited in any of aspects 1-18.

Aspect 20 is an apparatus for wireless communication, the apparatus comprising means for implementing a method as described in any of aspects 1 to 18.

Aspect 21 is a computer-readable medium storing computer-executable code, wherein the code, when executed by a processor, causes the processor to implement a method as described in any of aspects 1 to 18.

Aspect 22 is a method of wireless communication for a UE, the method comprising: receiving an activation indication for a secondary cell (SCell) from a serving cell based on a first reference signal, the activation indication indicating transmission of the first reference signal for activating the SCell; identifying whether the first reference signal is transmitted as indicated; and upon identifying that the first reference signal is transmitted as indicated, activating the SCell based on one or more reference signals including the first reference signal or the second reference signal.

Aspect 23 is the method of aspect 22, further comprising: an Acknowledgement (ACK) is sent to the serving cell regarding receipt of an activation indication, wherein the activation indication is processed for a first duration after sending the ACK to the serving cell.

Aspect 24 is the method of any of aspects 22 and 23, wherein the first reference signal comprises at least one of a periodic tracking reference signal or an aperiodic tracking reference signal.

Aspect 25 is the method of any of aspects 22-24, wherein identifying whether the first reference signal is transmitted as indicated comprises: performing a clear channel assessment to determine whether the channel measurement is greater than a threshold; and in response to determining that the channel measurement is greater than the threshold, identifying that the first reference signal is not being transmitted as indicated by the activation indication.

Aspect 26 is the method of any of aspects 22-25, further comprising: an instruction to cancel transmission of the first reference signal is received from the serving cell, wherein the UE identifies that the first reference signal is not transmitted in response to receiving the instruction to cancel the transmitted first reference signal, and wherein the instruction to cancel the activation indication for the SCell based on the first reference signal is indicated by one of MAC-CE or DCI.

Aspect 27 is the method of any of aspects 22-26, further comprising: upon identifying that the first reference signal is not being transmitted as indicated, receiving a second reference signal from the SCell; and upon identifying that the first reference signal is not being transmitted as indicated, activating the SCell based on the second reference signal received from the SCell.

Aspect 28 is the method of aspect 27, wherein the UE is not later than in the slotAn SCell, wherein the activation indication is received in slot n, T _HARQ Is the period of time between receiving an activation indication from the serving cell and sending an ACK for the activation indication to the serving cell, T _{activation_time} SCell activation time between transmission of ACK of activation indication and second duration after receiving second reference signal, and T _{CSI_reporting} Is to obtain one or more first availableDelay uncertainty in CSI reporting resources.

Aspect 29 is the method of any of aspects 22-26, further comprising: and receiving a new activation indication indicating transmission of a second reference signal for activating the SCell, wherein upon receiving the new activation indication, the UE recognizes that the first reference signal is not transmitted as indicated.

Aspect 30 is the method of aspect 29, wherein the UE is not later than in the slotAn SCell, wherein the activation indication is received in slot n, T _HARQ Is the period of time between receiving an activation indication from the serving cell and sending an ACK for the activation indication to the serving cell, T _{activation_time} SCell activation time between transmission of ACK of activation indication and second duration after receiving second reference signal, and T _{CSI_reporting} Is the delay uncertainty in acquiring one or more first available CSI reporting resources.

Aspect 31 is the method according to any of aspects 22-30, wherein the SCell comprises a plurality of subbands, and wherein identifying whether the first reference signal is transmitted as indicated comprises: performing a clear channel assessment to determine whether the channel measurement is greater than a threshold for at least one of the plurality of subbands; and upon determining that the channel measurement for at least one of the plurality of subbands is greater than the threshold, identifying that the first reference signal is not being transmitted as indicated.

Aspect 32 is an apparatus for wireless communication, the apparatus comprising at least one processor coupled to a memory and configured to implement a method as described in any of aspects 22 to 31.

Aspect 33 is an apparatus for wireless communication, the apparatus comprising means for implementing a method as described in any of aspects 22 to 31.

Aspect 34 is a computer-readable medium storing computer-executable code, wherein the code, when executed by a processor, causes the processor to implement a method as described in any of aspects 22 to 31.

Claims (30)

1. An apparatus for wireless communication at a User Equipment (UE), comprising:

a memory; and

at least one processor coupled to the memory and configured to:

receiving an activation indication for a secondary cell (SCell) from a serving cell;

receiving a first reference signal from the SCell, the first reference signal comprising at least one temporary reference signal;

identifying whether a second reference signal is received after processing the activation indication and before expiration of an SCell activation time; and

upon identifying receipt of the second reference signal, the SCell is activated based on one or more reference signals comprising at least one of the first reference signal or the second reference signal.

2. The apparatus of claim 1, wherein the at least one processor is further configured to:

an Acknowledgement (ACK) is sent to the serving cell regarding receipt of the activation indication, wherein the activation indication is processed for a first duration after the ACK is sent to the serving cell.

3. The apparatus of claim 1, wherein the at least one processor is further configured to:

a Channel State Information (CSI) report is transmitted based on which the UE activates one of the first reference signal or the second reference signal of the SCell.

4. The apparatus of claim 1, wherein the at least one temporary reference signal comprises an aperiodic tracking reference signal and the activation indication indicates the aperiodic tracking reference signal transmitted by the SCell, and

wherein the activation indication is received via one of a Medium Access Control (MAC) Control Element (CE) (MAC-CE) or Downlink Control Information (DCI).

5. The apparatus of claim 4, wherein the SCell is activated no later than in time slot n+k, wherein the activation indication is received in time slot n, and K is determined based on at least one of: a time period between receiving the activation indication from the serving cell and sending an Acknowledgement (ACK) of the activation indication to the serving cell, the SCell activation time between transmission of the ACK of the activation indication and a second duration after receiving the at least one temporary reference signal, and a delay uncertainty in acquiring one or more first available CSI reporting resources.

6. The apparatus of claim 1, wherein the at least one temporary reference signal comprises a periodic tracking reference signal, and the activation indication indicates the periodic tracking reference signal transmitted by the SCell, and

Wherein the activation indication is received via Radio Resource Control (RRC) signaling.

7. The apparatus of claim 6, wherein the SCell is activated no later than in time slot n+k, wherein the activation indication is received in time slot n, and K is determined based on at least one of: a time period between receiving the activation indication from the serving cell and sending an Acknowledgement (ACK) of the activation indication to the serving cell, the SCell activation time between transmission of the ACK of the activation indication and a second duration after receiving a last one of the one or more reference signals based on which the UE activates the SCell, and a delay uncertainty in acquiring one or more first available CSI reporting resources.

8. The apparatus of claim 6, wherein the activation indication is received via Radio Resource Control (RRC) signaling.

9. The apparatus of claim 1, wherein the first reference signal is received from an active serving cell, and

wherein the at least one processor is further configured to identify whether the second reference signal is received from the active serving cell.

10. The apparatus of claim 1, wherein the first reference signal and the second reference signal are assumed to be quasi co-located with each other.

11. The apparatus of claim 1, wherein the activation indication indicates that multiple scells are activated simultaneously, the multiple scells comprising a first SCell and a second SCell.

12. The apparatus of claim 11, wherein the first SCell and the second SCell are in a same frequency band, in adjacent carriers in the same frequency band, or in a frequency range.

13. The apparatus of claim 11, wherein the plurality of scells are activated based on the one or more reference signals comprising the at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal based on earliest received from the plurality of scells.

14. The apparatus of claim 11, wherein the plurality of scells are activated based on the one or more reference signals comprising the at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, whichever is received within an earliest activation time for the plurality of scells.

15. The apparatus of claim 11, wherein the plurality of scells are activated based on the one or more reference signals comprising the at least one temporary reference signal comprising an aperiodic tracking reference signal or a periodic tracking reference signal, whichever is received last from the plurality of scells.

16. The apparatus of claim 1, wherein the SCell is activated no later than in time slot n+k, wherein: the activation indication is received in time slot n, and K is determined based on at least one of: the method may include receiving, from the serving cell, the activation indication, a time period between the reception of the activation indication and an Acknowledgement (ACK) of the activation indication to the serving cell, the SCell activation time between transmission of the ACK of the activation indication and a second duration after receiving two or four reference signals including one of the first reference signal or the second reference signal, and a delay uncertainty in acquiring one or more first available CSI reporting resources.

17. An apparatus for wireless communication at a User Equipment (UE), comprising:

A memory; and

at least one processor coupled to the memory and configured to:

receiving an activation indication for a secondary cell (SCell) from a serving cell based on a first reference signal, the activation indication indicating transmission of the first reference signal for activating the SCell;

identifying whether the first reference signal is transmitted as indicated; and

upon identifying that the first reference signal is transmitted as indicated, the SCell is activated based on one or more reference signals including the first reference signal or a second reference signal.

18. The apparatus of claim 17, in which the at least one processor is further configured:

an Acknowledgement (ACK) is sent to the serving cell regarding receipt of the activation indication, wherein the activation indication is processed for a first duration after the ACK is sent to the serving cell.

19. The apparatus of claim 17, wherein the first reference signal comprises at least one of a periodic tracking reference signal or an aperiodic tracking reference signal.

20. The apparatus of claim 17, wherein to identify whether the first reference signal is transmitted as indicated, the at least one processor is configured to:

Performing a clear channel assessment to determine whether the channel measurement is greater than a threshold; and

in response to determining that the channel measurement is greater than the threshold, it is identified that the first reference signal is not being transmitted as indicated by the activation indication.

21. The apparatus of claim 17, wherein the at least one processor is configured to:

receiving an instruction from the serving cell to cancel the transmission of the first reference signal, wherein the UE identifies that the first reference signal is not transmitted in response to receiving the instruction to cancel the first reference signal,

wherein the instruction to cancel the activation indication for the SCell based on the first reference signal is indicated by one of a Medium Access Control (MAC) Control Element (CE) (MAC-CE) or Downlink Control Information (DCI).

22. The apparatus of claim 17, wherein the at least one processor is configured to:

upon identifying that the first reference signal is not being transmitted as indicated, receiving the second reference signal from the SCell; and

upon identifying that the first reference signal is not being transmitted as indicated, the SCell is activated based on the second reference signal received from the SCell.

23. The apparatus of claim 22, wherein the SCell is activated no later than in time slot n+k, wherein the activation indication is received in time slot n, and K is determined based on at least one of: a time period between receiving the activation indication from the serving cell and sending an Acknowledgement (ACK) of the activation indication to the serving cell, an SCell activation time between the transmission of the ACK of the activation indication and a second duration after receiving the second reference signal, and a delay uncertainty in acquiring one or more first available CSI reporting resources.

24. The apparatus of claim 17, in which the at least one processor is further configured:

receiving a new activation indication, the new activation indication indicating a transmission of the second reference signal for activating the SCell,

wherein upon receiving the new activation indication, the UE recognizes that the first reference signal is not transmitted as indicated.

25. The apparatus of claim 24, wherein the SCell is activated no later than in time slot n+k, wherein the activation indication is received in time slot n, and K is determined based on at least one of: a time period between receiving the activation indication from the serving cell and sending an Acknowledgement (ACK) of the activation indication to the serving cell, an SCell activation time between the transmission of the ACK of the activation indication and a second duration after receiving the second reference signal, and a delay uncertainty in acquiring one or more first available CSI reporting resources.

26. The apparatus of claim 17, wherein the SCell comprises a plurality of subbands, and

wherein, to identify whether the first reference signal is transmitted as indicated, the at least one processor is configured to:

performing a clear channel assessment to determine whether a channel measurement is greater than a threshold for at least one of the plurality of subbands; and

upon determining that the channel measurement for at least one of the plurality of subbands is greater than the threshold, it is identified that the first reference signal is not being transmitted as indicated.

27. A method of wireless communication at a User Equipment (UE), comprising:

receiving an activation indication for a secondary cell (SCell) from a serving cell;

receiving a first reference signal from the SCell, the first reference signal comprising at least one temporary reference signal;

identifying whether a second reference signal is received after processing the activation indication and before expiration of an SCell activation time; and

upon identifying receipt of the second reference signal, the SCell is activated based on one or more reference signals comprising at least one of the first reference signal or the second reference signal.

28. The method of claim 27, wherein the SCell is activated no later than in time slot n+k, wherein the activation indication is received in time slot n, and K is determined based on at least one of: a time period between receiving the activation indication from the serving cell and sending an Acknowledgement (ACK) of the activation indication to the serving cell, the SCell activation time between transmission of the ACK of the activation indication and a second duration after receiving the at least one temporary reference signal, and a delay uncertainty in acquiring one or more first available CSI reporting resources.

29. A method of wireless communication at a User Equipment (UE), comprising:

receiving an activation indication for a secondary cell (SCell) from a serving cell based on a first reference signal, the activation indication indicating transmission of the first reference signal for activating the SCell;

identifying whether the first reference signal is transmitted as indicated; and

upon identifying that the first reference signal is transmitted as indicated, the SCell is activated based on one or more reference signals including the first reference signal or a second reference signal.

30. The method of claim 29, wherein the SCell is activated no later than in time slot n+k, wherein the activation indication is received in time slot n, and K is determined based on at least one of: a time period between receiving the activation indication from the serving cell and sending an Acknowledgement (ACK) of the activation indication to the serving cell, an SCell activation time between the transmission of the ACK of the activation indication and a second duration after receiving the second reference signal, and a delay uncertainty in acquiring one or more first available CSI reporting resources.