Method and apparatus related to beam recovery in a secondary cell

Abstract

Various aspects and features described herein relate to a method for beam failure recovery in an SCell with the assistance of a PCell. In one aspect, a device (e.g., a UE) may detect an SCell beam failure and, in response to detecting the SCell beam failure, send a scheduling request to a base station via the PCell. The UE may receive a first message from the base station via the PCell, the first message including one of an uplink grant or a trigger for an UL report. The UE may send a second message via the PCell, the second message indicating the SCell beam failure and a preferred candidate beam associated with the SCell. The UE may receive a CORESET TCI state activation from the base station via the PCell, and determine a control channel associated with the preferred candidate beam based on the CORESET TCI state activation signal.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 700,216, filed on July 18, 2018, entitled “METHODS AND APPARATUS RELATED TO BEAM RECOVERY IN THE SECONDARY CELL,” U.S. Provisional Patent Application No. 62 / 700,308, filed on July 18, 2018, entitled “METHODS AND APPARATUS RELATED TO BEAM RECOVERY IN THE SECONDARY CELL,” and U.S. Patent Application No. 16 / 415,133, filed on May 17, 2019, entitled “METHODS AND APPARATUS RELATED TO BEAM RECOVERY IN THE SECONDARY CELL,” the entire contents of which are hereby expressly incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to communication systems, and more particularly to methods and apparatus related to beam recovery. Background Art

[0004] Wireless communication systems are widely deployed to provide various telecommunication services, such as telephony, video, data, messaging, broadcast, etc. Typical wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

[0005] These multiple access technologies have been used in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at municipal, national, regional, and even global levels. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of the continued mobile broadband evolution promulgated by the Third Generation Partnership Project (3GPP) and is designed to meet new requirements related to latency, reliability, security, scalability (e.g., with the Internet of Things (IoT)), and other requirements. 5G NR includes services related to enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low latency communications (URLLC). Certain aspects of 5G NR may be built on the 4G Long Term Evolution (LTE) standard. Further improvements to 5G NR technology are needed. These improvements may also apply to other multiple access technologies and the telecommunication standards that adopt these technologies. Summary of the invention

[0006] A brief summary of one or more aspects is presented below to provide a basic understanding of these aspects. The present disclosure is not an exhaustive overview of all conceivable aspects, and is neither intended to identify the key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its only purpose is to present some concepts of one or more aspects in a simplified form as a prelude to a more detailed description presented later.

[0007] The various aspects and features described herein relate to a method for beam failure recovery in an SCell with the assistance of a PCell in a communication system that supports PCell and SCell carrier aggregation operations. In one aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a user equipment (UE). The apparatus may be configured to detect an SCell beam failure. The apparatus may also be configured to send a scheduling request (SR) to a base station via the PCell in response to detecting an SCell beam failure. The apparatus may also be configured to receive a first message from a base station via the PCell, the first message including one of an uplink (UL) authorization or a trigger for a UL report. The apparatus may also be configured to send a second message to the base station via the PCell, the second message including information indicating an SCell beam failure.

[0008] In another aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE configured to detect an SCell beam failure. The apparatus may also be configured to send an SR to a base station via a PCell, the SR including information indicating an SCell beam failure. The apparatus may also be configured to receive a physical downlink control channel (PDCCH) command indicating a resource set associated with the SCell from the base station via the PCell in response to the SR.

[0009] In another aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a base station. The apparatus may be configured to receive a scheduling request (SR) from a user equipment (UE) via a primary cell (PCell) based on detecting a secondary cell (SCell) beam failure at the UE. The apparatus may also be configured to send a first message from the PCell to the UE, the first message including one of an uplink (UL) grant or a trigger for a UL report. The apparatus may also be configured to receive a second message from the UE at the PCell, the second message including information indicating an SCell beam failure.

[0010] In another aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a base station. The apparatus may be configured to receive a scheduling request (SR) from a user equipment (UE) via a primary cell (PCell), the SR including information indicating a secondary cell (SCell) beam failure. The apparatus may also be configured to send a physical downlink control channel (PDCCH) command indicating a resource set associated with the SCell from the PCell in response to the SR.

[0011] To accomplish the foregoing and related ends, one or more aspects include features hereinafter fully described and particularly pointed out in the claims. The following description and the accompanying drawings set forth in detail certain illustrative features of one or more aspects. However, these features are indicative of only some of the various ways in which the principles of the various aspects may be employed, and this description is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0013] Figure 2A , Figure 2B , Figure 2C and Figure 2D Diagrams showing examples of a first 5G / NR frame, a DL channel within a 5G / NR subframe, a second 5G / NR frame, and a UL channel within a 5G / NR subframe, respectively.

[0014] Figure 3 is a diagram showing an example of a base station and a user equipment (UE) in an access network.

[0015] Figure 4 is a diagram showing a base station communicating with a UE.

[0016] Figure 5 An example of an independent SCell beam recovery process according to one aspect is shown.

[0017] Figure 6 An example of an SCell beam recovery process with PCell assistance with beam correspondence according to an aspect is shown.

[0018] Figure 7 An example of an SCell beam recovery process with PCell assistance but without hypothesized beam correspondence is shown according to one aspect.

[0019] Figure 8 Another example of an SCell beam recovery process with PCell assistance according to an aspect is shown.

[0020] Fig. 9 Yet another example of an SCell beam recovery procedure with PCell assistance according to an aspect is shown.

[0021] Figures 10 to 12 is a flow chart of an example method of wireless communication.

[0022] Fig.13 is a conceptual data flow diagram illustrating the flow of data between different parts / components in an example apparatus.

[0023] Fig.14 is a diagram showing an example of a hardware implementation for an apparatus employing a processing system.

[0024] Fig.15 and Fig.16 is a flow chart of an example method of wireless communication.

[0025] Fig.17 is a conceptual data flow diagram illustrating the flow of data between different parts / components in an example apparatus.

[0026] Fig.18 is a diagram showing an example of a hardware implementation for an apparatus employing a processing system. DETAILED DESCRIPTION

[0027] The detailed description set forth below in conjunction with the accompanying 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. In order to provide a thorough understanding of each concept, the detailed description includes specific details. However, it will be apparent to those skilled in the art that these concepts may be implemented without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid blurring such concepts.

[0028] Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements") and illustrated in the accompanying drawings. These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0029] For example, an element, or any part of an element, or any combination of elements can be implemented as a "processing system", which includes one or more processors. Examples of processors include: microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set operations (RISC) processors, systems on chip (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform various functions described throughout the present disclosure. One or more processors in a processing system can execute software. Whether referred to as software, firmware, middleware, microcode, hardware description language, or other names, software should be broadly interpreted as meaning instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, processes, functions, etc.

[0030] Accordingly, in one or more example embodiments, the described functions can be implemented with hardware, software, or any combination thereof. If implemented with software, the functions can be stored on a computer-readable medium or encoded as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media. Storage media can be any available media that can be accessed by a computer. By way of example and not limitation, such computer-readable media can include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, a combination of computer-readable media of the above types, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

[0031] As used herein, the term "computer-readable medium" is expressly defined to include any type of computer-readable storage devices and / or storage disks, and to exclude propagating signals and transmission media. As used herein, "computer-readable medium," "machine-readable medium," "computer-readable memory," and "machine-readable memory" are used interchangeably.

[0032] Figure 1 1 is a diagram showing an example of a wireless communication system and access network 100. The 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 (5GC)). The base station 102 may include a macro cell (a high-power cellular base station) and / or a small cell (a low-power cellular base station). A macro cell includes a base station. A small cell includes a femto cell, a pico cell, and a micro cell.

[0033] Base stations 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with EPC 160 via a backhaul link 132 (e.g., an S1 interface). Base stations 102 configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN)) may interface with core network 190 via a backhaul link 184. Base stations 102 may perform one or more of the following functions, among other functions: transmission of user data, radio channel encryption and decryption, integrity protection, header compression, mobility 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 service (MBMS), subscriber and device tracking, RAN information management (RIM), paging, positioning, and transmission of warning messages. Base stations 102 may communicate with each other via backhaul links 134 (eg, X2 interfaces) directly or indirectly (eg, via EPC 160 or core network 190). Backhaul links 134 may be wired or wireless.

[0034] Base station 102 can communicate with UE 104 wirelessly. Each base station in base station 102 can provide communication coverage for a corresponding geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, small cell 102' can have a coverage area 110' that overlaps with the coverage area 110 of one or more macro base stations 102. A network including both small cells and macro cells can be referred to as a heterogeneous network. A heterogeneous network can also include a home evolved Node B (eNB) (HeNB), which can provide services to a restricted group called a closed subscriber group (CSG). The communication link 120 between base station 102 and UE 104 can include an uplink (UL) (also referred to as a reverse link) transmission from UE 104 to base station 102 and / or a downlink (DL) (also referred to as a forward link) transmission from base station 102 to UE 104. The communication link 120 can use multiple input multiple output (MIMO) antenna technology, which includes spatial multiplexing, beamforming and / or transmit diversity. The communication link can be through one or more carriers. The base station 102 / UE 104 may use spectrum of up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in carrier aggregation of up to a total of Yx MHz (x component carriers) for transmission in each direction. The carriers may be adjacent to each other or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL ​​than for UL). The component carrier may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell) and the secondary component carrier may be referred to as a secondary cell (SCell).

[0035] Certain UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use DL / UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). The D2D communication may be through a variety of wireless D2D communication systems, such as FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on IEEE 802.11 standards, LTE, or NR.

[0036] The wireless communication system may also include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 via a communication link 154 in the 5 GHz unlicensed frequency spectrum. When communicating in the unlicensed frequency spectrum, the STA 152 / AP 150 may perform a clear channel assessment (CCA) before communicating to determine whether the channel is available.

[0037] The small cell 102' may operate in licensed and / or unlicensed frequency spectrum. When operating in unlicensed frequency spectrum, the small cell 102' may employ NR and use the same 5 GHz unlicensed frequency spectrum as the 5 GHz unlicensed spectrum used by the Wi-Fi AP 150. The small cell 102' employing NR in the unlicensed frequency spectrum may improve coverage and / or increase capacity of the access network.

[0038] The base station 102 (whether a small cell 102' or a large cell (e.g., a macro base station)) may include an eNB, a gNodeB (gNB), or other types of base stations. Some base stations (e.g., gNB 180) may operate in the traditional sub-6 GHz spectrum, in millimeter wave (mmW) frequencies, and / or near mmW frequencies to communicate with the UE 104. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as a mmW base station. Extremely high frequency (EHF) is a portion of RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and has a wavelength between 1 mm and 10 mm. Radio waves in this band may be referred to as millimeter waves. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 mm. The super high frequency (SHF) band extends between 3 GHz and 30 GHz and is also referred to as centimeter waves. Communications using the mmW / near mmW radio frequency bands (e.g., 3 GHz to 300 GHz) have extremely high path losses and short distances. The mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short range.

[0039] The base station 180 may transmit beamformed signals in one or more transmit directions 182' to the UE 104. The UE 104 may receive beamformed signals from the base station 180 in one or more receive directions 182". The UE 104 may also transmit beamformed signals to the base station 180 in one or more transmit directions. The base station 180 may receive beamformed signals from the UE 104 in one or more receive directions. The base station 180 / UE 104 may perform beam training to determine the best receive direction and transmit direction for each of the base station 180 / UE 104. The transmit direction and receive direction of the base station 180 may be the same or may be different. The transmit direction and receive direction of the UE 104 may be the same or may be different.

[0040] The EPC 160 may include a mobility 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. The 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. Typically, the MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are transmitted through the serving gateway 166, which itself is connected to the PDN gateway 172. The PDN gateway 172 provides UE IP address allocation and other functions. The PDN gateway 172 and the BM-SC 170 are connected to IP services 176. The IP services 176 may include the Internet, an intranet, an IP multimedia subsystem (IMS), a PS streaming service, and / or other IP services. The BM-SC 170 may provide functionality for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services within a public land mobile network (PLMN), and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS services to base stations 102 belonging to a multicast broadcast single frequency network (MBSFN) area that broadcasts a specific service, and may be responsible for session management (start / stop) and collecting eMBMS-related billing information.

[0041] The core network 190 may include an access and mobility management function unit (AMF) 192, other AMFs 193, a session management function unit (SMF) 194, and a user plane function unit (UPF) 195. The AMF 192 may communicate with a unified data management unit (UDM) 196. The AMF 192 is a control node that handles signaling between the UE 104 and the core network 190. Typically, the AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are transmitted through the UPF 195. The UPF 195 provides UE IP address allocation and other functions. The UPF 195 is connected to an IP service 197. The IP service 197 may include the Internet, an intranet, an IP multimedia subsystem (IMS), a PS streaming service, and / or other IP services.

[0042] A base station may also be referred to as a gNB, a Node B, an evolved Node B (eNB), an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit receive point (TRP), or some other appropriate term. Base station 102 provides an access point to EPC 160 or core network 190 for UE 104. Examples of UE 104 include a cellular phone, a smart phone, a Session Initiation Protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio unit, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., an MP3 player), a camera, a game console, a tablet device, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor / actuator, a display, or any other similarly functional device. Some of UE 104 may be referred to as IoT devices (e.g., a parking meter, a gas pump, a toaster, a vehicle, a heart monitor, etc.). UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

[0043] Refer again Figure 1In certain aspects, the UE 104 and / or the base station 102 / 180 may be configured to manage one or more aspects of wireless communication via performing beam failure recovery processing in the SCell with the assistance of the PCell. For example, the UE 104 may include a UE SCell beam recovery component 198 configured to: detect a secondary cell (SCell) beam failure; in response to detecting the SCell beam failure, send a scheduling request (SR) to the base station via a primary cell (PCell); receive a first message from the base station via the PCell, the first message including one of an uplink (UL) grant or a trigger for a UL report; and send a second message to the base station via the PCell, the second message including information indicating the SCell beam failure. The base station 102 / 180 may include a base station SCell beam recovery component 199 configured to: receive an SR from the UE via the SCell and send a message including a UL grant trigger or a trigger for a UL report.

[0044] Although the following description may provide an example based on downlink communication, it should be understood that the concepts described herein may be applicable to uplink communication and / or sidelink communication. In addition, although the following description may focus on the 5G NR field, the concepts described herein may be applicable to other similar fields, such as LTE, LTE-A, CDMA, GSM, and / or other wireless technologies, where WUS resources may conflict with dedicated resources associated with a UE or system resources (e.g., shared resources) associated with multiple UEs.

[0045] Figure 2A FIG200 is a diagram showing an example of a first subframe within a 5G / NR frame structure. Figure 2B FIG230 is a diagram showing an example of DL channels within a 5G / NR subframe. Figure 2C Figure 250 shows an example of a second subframe within a 5G / NR frame structure. Figure 2D FIG280 is a diagram showing an example of UL channels within a 5G / NR subframe. The 5G / NR frame structure can be FDD (wherein, for a particular set of subcarriers (carrier system bandwidth), subframes within that subcarrier set are dedicated to either DL or UL), or can be TDD (wherein, for a particular set of subcarriers (carrier system bandwidth), subframes within that subcarrier set are dedicated to both DL and UL). Figure 2A , Figure 2CIn the example provided, the 5G / NR frame structure is assumed to be TDD, where subframe 4 is configured in slot format 28 (mostly DL), where D is DL, U is UL, and X is flexible between DL / UL, and subframe 3 is configured in slot format 34 (mostly UL). Although subframes 3 and 4 are shown in slot formats 34 and 28, respectively, any particular subframe can be configured in any of the various available slot formats 0-61. Slot formats 0 and 1 are full DL and full UL, respectively. Other slot formats 2-61 include a mix of DL, UL and flexible symbols. The UE is configured in the slot format (dynamically configured through DL control information (DCI), or semi-statically / statically configured through radio resource control (RRC) signaling) through the received slot format indicator (SFI). It should be noted that the following description also applies to the 5G / NR frame structure as TDD.

[0046] Other wireless communication technologies may have different frame structures and / or different channels. A frame (10ms) may be divided into 10 equally sized subframes (1ms). Each subframe may include one or more time slots. A subframe may also include a microslot, which may include 7, 4, or 2 symbols. Depending on the slot configuration, each time slot may include 7 or 14 symbols. For slot configuration 0, each time slot may include 14 symbols, and for slot configuration 1, each time slot may include 7 symbols. The symbol on the DL may be a cyclic prefix (CP) OFDM (CP-OFDM) symbol. The symbol on the UL may be a CP-OFDM symbol (for high throughput scenarios) or a discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbol (also known as a single carrier frequency division multiple access (SC-FDMA) symbol) (for power-limited scenarios; limited to single stream transmission). The number of slots within a subframe may be based on the slot configuration and the parameter set (numerology). For slot configuration 0, different parameter sets μ0 to 5 allow 1, 2, 4, 8, 16 and 32 slots per subframe, respectively. For slot configuration 1, different parameter sets 0 to 2 allow 2, 4 and 8 slots per subframe, respectively. Accordingly, for slot configuration 0 and parameter set μ, there are 14 symbols / slot and 2μ slots / subframe. The subcarrier spacing and symbol length / duration are functions of the parameter set. The subcarrier spacing can be equal to, where μ is parameter set 0 to 5. Therefore, parameter set μ=0 has a subcarrier spacing of 15kHz, and parameter set μ=5 has a subcarrier spacing of 480kHz. The symbol length / duration is inversely proportional to the subcarrier spacing. FIG. 2A to FIG. 2D An example is provided for slot configuration 0 with 14 symbols per slot and parameter set μ=0 with 1 slot per subframe. The subcarrier spacing is 15 kHz and the symbol duration is approximately 66.7 μs.

[0047] The resource grid can be used to represent the frame structure. Each time slot includes a resource block (RB) (also called a physical RB (PRB)), which extends over 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0048] like Figure 2A As shown in , some of the REs carry reference (pilot) signals (RS) for the UE. The RS may include a demodulation RS (DM-RS) for channel estimation at the UE (indicated as Rx for a specific configuration, where 100x is the port number, but other DM-RS configurations are also possible) and a channel state information reference signal (CSI-RS). The RS may also include a beam measurement RS (BRS), a beam refinement RS (BRRS), and a phase tracking RS (PT-RS).

[0049] Figure 2B Examples of various DL channels within a subframe of a frame are shown. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs), each CCE including nine RE groups (REGs), each REG including four consecutive REs in one OFDM symbol. The primary synchronization signal (PSS) may be within symbol 2 of a particular subframe of a frame. The PSS is used by UE104 to determine the subframe / symbol timing and the physical layer identity. The secondary synchronization signal (SSS) may be within symbol 4 of a particular subframe of a frame. The SSS is used by the UE to determine the physical layer cell identity group number and the radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE may determine the physical cell identifier (PCI). Based on the PCI, the UE may determine the location of the above-mentioned DM-RS. The physical broadcast channel (PBCH), which carries the master information block (MIB), may be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block. The MIB provides the number of RBs in the system bandwidth and the system frame number (SFN). The Physical Downlink Shared Channel (PDSCH) carries user data, broadcast system information (eg, System Information Block (SIB)) that is not transmitted through the PBCH, and paging messages.

[0050] like Figure 2CAs shown in , some of the REs carry DM-RS for channel estimation at the base station (indicated as R for one specific configuration, but other DM-RS configurations are also possible). The UE can send DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH). The PUSCH DM-RS can be sent in the first or first two symbols of the PUSCH. Depending on whether a short PUCCH or a long PUCCH is sent and depending on the specific PUCCH format used, the PUCCH DM-RS can be sent in different configurations. Although not shown, the UE can send a sounding reference signal (SRS). The SRS can be used by the base station for channel quality estimation to achieve frequency-dependent scheduling on the UL.

[0051] Figure 2D Examples of various UL channels within a subframe of a frame are shown. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), and HARQ ACK / NACK feedback. The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0052] Figure 33 is a block diagram of a base station 310 communicating with a UE 350 in an access network. In the DL, IP packets from the EPC 160 may be provided to a controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functions. Layer 3 includes a radio resource control (RRC) layer, while layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller / processor 375 provides RRC layer functions associated with broadcasting of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functions associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and switching support functions; RLC layer functions associated with transmission of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0053] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functions associated with various signal processing functions. Layer 1 (which includes the physical (PHY) layer) may include error detection on the transmission channel, forward error correction (FEC) encoding / decoding of the transmission channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 processes the mapping to the signal constellation diagram based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols can then be split into parallel streams. Each stream can then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time domain and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to generate multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine coding and modulation schemes, as well as for spatial processing. Channel estimates may be derived based on reference signals and / or channel condition feedback sent by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0054] At the UE 350, each receiver 354RX receives a signal through its respective antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to a receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functions associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial stream destined for the UE 350. If multiple spatial streams are destined for the UE 350, they can be merged 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 OFDM symbol stream for each subcarrier of the OFDM signal. The symbols and reference signals on each subcarrier are recovered and demodulated by determining the most likely signal constellation point sent by the base station 310. These soft decisions can be based on channel estimates calculated by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally sent on the physical channel by the base station 310. The data and control signals are then provided to the controller / processor 359, which implements layer 3 and layer 2 functions.

[0055] The controller / processor 359 may be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error correction using an ACK and / or NACK protocol to support HARQ operations.

[0056] Similar to the functions described for DL ​​transmission performed in conjunction with the base station 310, the controller / processor 359 provides RRC layer functions associated with system information (e.g., MIB, SIB) capture, RRC connection, and measurement reporting; 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 through ARQ, concatenation, segmentation and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and 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 through HARQ, priority handling, and logical channel prioritization.

[0057] The TX processor 368 may select an appropriate coding and modulation scheme and facilitate spatial processing using channel estimates derived by the channel estimator 358 from a reference signal or feedback transmitted by the base station 310. The spatial streams generated by the TX processor 368 may be provided via separate transmitters 354TX to different antennas 352. Each transmitter 354TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0058] At the base station 310, the UL transmission is processed in a manner similar to that described in conjunction with the receiver functionality at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers the information modulated onto the RF carrier and provides the information to the RX processor 370.

[0059] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport channels and logical channels, packet reassembly, decryption, header decompression, control signal processing to recover IP packets from the UE 350. The IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error correction using ACK and / or NACK protocols to support HARQ operations.

[0060] At least one of the TX processor 316, the RX processor 370, and / or the controller / processor 375 of the base station 310 may be configured to perform a combined Figure 1 Various aspects are described for the base station SCell beam recovery component 199.

[0061] At least one of the RX processor 356, the TX processor 368, and / or the controller / processor 359 of the UE 350 may be configured to perform a combined Figure 1 Various aspects described herein with respect to the UE SCell beam recovery component 198.

[0062] Figure 4 4 is a diagram 400 showing a base station 402 communicating with a UE 404. Figure 4 , the base station 402 may send a beamformed signal to the UE 404 in one or more of directions 402a, 402b, 402c, 402d, 402e, 402f, 402g, 402h. The UE 404 may receive the beamformed signal from the base station 402 in one or more receive directions 404a, 404b, 404c, 404d. The UE 404 may also send a beamformed signal to the base station 402 in one or more of directions 404a-404d. The base station 402 may receive the beamformed signal from the UE 404 in one or more of receive directions 402a-402h. The base station 402 / UE 404 may perform beam training to determine the best receive direction and transmit direction for each of the base station 402 / UE 404. The transmit direction and receive direction of the base station 402 may be the same or may be different. The transmit direction and receive direction of the UE 404 may be the same or may be different.

[0063] Some wireless networks, such as 5th generation cellular networks, may employ millimeter wave (mmWave or mmW) frequencies to increase network capacity. The use of mmWave frequencies may be in addition to microwave frequencies (e.g., in sub-6 GHz bands), which may also be supported for communications, such as when utilizing carrier aggregation. However, communications at high millimeter wave frequencies may require directionality (e.g., communication via directional beams) to compensate for higher propagation losses. The base station and / or UE may need to align their beams during initial access and data transmission to ensure maximum gain. The base station and / or UE may determine the best beam for communicating with each other, and subsequent communications between the base station and the UE may be via the selected beam. However, due to UE mobility / movement, beam reconfiguration at the base station, and / or other factors, sometimes a downlink beam (e.g., including a downlink control link) at the UE (which may have been the preferred active beam until recently) may not be detected, or the signal quality may become below a threshold, causing the UE to view it as a beam / link failure.

[0064] A beam recovery process may be employed to recover from a control link failure. A control link failure may refer to, for example, a failure to detect a strong (e.g., signal power greater than a threshold) active beam corresponding to a control channel that transmits control information from the network. In certain aspects, to facilitate beam failure detection, the UE may be preconfigured with beam IDs of a first set of beams to be monitored (also referred to as setq_0), a monitoring period, a reference signal received power (RSRP) threshold, etc. For example, recovery may be triggered when the RSRP (detected by the UE) associated with one or more monitored beams drops below a threshold. The recovery process may include the UE identifying a new beam, for example, from a second set of possible beams (corresponding to which beam IDs may be included in a second set referred to as setq_1), and performing a RACH process using preconfigured time and frequency resources corresponding to the new preferred beam. Beam IDs corresponding to beams in the second set of beams (setq_1) may be preconfigured in the UE for beam failure recovery purposes. For example, the UE may monitor downlink beams (based on beam IDs and resources identified in the second set), perform measurements, and determine (e.g., based on the measurements) which beam among all received and measured beams from the UE's perspective may be the best for reception at the UE. If beam correspondence is assumed (e.g., the best receive beam direction is also considered the best transmit beam direction), the UE may assume the same beam configuration for reception and transmission. In other cases where beam correspondence is not assumed (e.g., deemed inappropriate in a given scenario or for other reasons), the UE may perform a RACH procedure (e.g., using preconfigured time and frequency resources indicated in the second set) to identify the uplink beam. Performing the RACH procedure using the preconfigured time and frequency resources may include, for example, sending a RACH preamble on one or more beams (corresponding to beam IDs in the second set) on allocated RACH resources corresponding to the one or more beams. Based on the RACH procedure, the UE may be able to determine and confirm with the base station which uplink direction may be the best beam direction for an uplink channel (e.g., PUCCH). In this way, the uplink and downlink beams can be reestablished and beam recovery can be completed.

[0065] In certain aspects, carrier aggregation may be utilized where communications between a base station and a UE may be supported via multiple carrier components (e.g., PCell and SCell). For example, the PCell may correspond to a microwave band and / or other relatively lower frequency bands lower than the mmW band, and the SCell may correspond to the mmW band. On the one hand, when the communication system supports PCell and SCell operations, the assistance of the PCell may be utilized to enhance the SCell recovery process. In other words, if a beam / link failure occurs in an SCell, the assistance of the PCell may be utilized to facilitate the SCell beam recovery process. Such an approach may reduce delays and wait times associated with the beam recovery process, and / or may allow faster recovery of failed links in the SCell.

[0066] Various techniques and aspects for SCell recovery assisted by PCell are described herein. For example, consider FR1(PCell)+FR2(SCell) operation as shown in the various figures and discussed below, where FR1 may correspond to a sub-6 GHz band and FR2 may correspond to a mmWave band. Figures 5 to 9 In the examples shown and discussed below, for simplicity, the PCell and SCell are shown as being associated with base station 502 (e.g., hardware / circuitry for implementing the PCell and SCell may be collocated at base station 502). However, in some other configurations, the PCell and SCell may be associated with different base stations that may be synchronized.

[0067] Figure 5 5 is a diagram illustrating an example of an independent SCell beam recovery process according to one aspect. Figure 5 The beam recovery process shown in the example of can be considered as a baseline standalone beam recovery process, where beam recovery is performed without the assistance of PCell.

[0068] At 510, UE 504 may detect an SCell beam failure. For example, UE 504 may detect an SCell beam failure when one or more preferred beams (in the SCell / FR2 band) via which UE 504 may communicate with base station 502 cannot be detected at UE 504 and / or a quality metric associated with a signal received via one or more beams is below a threshold. For example, when the RSRP associated with one or more monitored beams in the SCell drops below a threshold (e.g., a preconfigured threshold), UE 504 may consider this to be an SCell beam failure. In one aspect, a beam recovery procedure may be triggered after UE 504 detects an SCell beam failure.

[0069] At 512, the UE 504 may perform a RACH procedure on the candidate beams. As discussed above, a beam ID corresponding to a set of candidate beams may be pre-configured at the UE 504, and the UE 504 may perform a RACH procedure on one or more candidate beams from the set of candidate beams. Performing the RACH procedure may include the UE 504 sending a RACH preamble (which may be pre-stored or provided to the UE 504 by the base station 502) on one or more candidate beams on pre-configured RACH resources corresponding to the one or more candidate beams. The pre-configured RACH resources may correspond to an SCell (e.g., in a mmW frequency band). The base station 502 may receive a PRACH preamble sent by the UE 504 via the candidate beams.

[0070] At 514, the base station 502 may send a response with a cell-radio network temporary identifier (C-RNTI) to the UE 504 via a PDCCH associated with the SCell. For example, the response may include cyclic redundancy check (CRC) bits scrambled by the C-RNTI. The response with the C-RNTI sent via the SCell PDCCH may be a RACH response, which may be sent specifically in response to a RACH preamble transmission from the UE 504 for beam failure recovery.

[0071] At 516, the UE 504 may receive a response with a C-RNTI from the base station 502 via the SCell PDCCH. After processing the received response and having determined that the received PDCCH is addressed to the C-RNTI, the UE 504 may determine that a beam failure recovery (BFR) procedure has been completed. According to one aspect, the C-RNTI may be mapped to a base station that determines the best beam direction for an uplink channel (e.g., PUCCH) for the UE 504. Thus, upon receiving a response with a C-RNTI from the base station 502, at 516, the UE 504 may be able to determine the best uplink beam that may be most suitable for the uplink channel. Once the UE 504 detects the C-RNTI PDCCH, the UE 504 may continue to monitor the PDCCH candidates in the search space until the UE 504 receives a MAC control element (MAC-CE) activation command for a transmission configuration indicator (TCI) state.

[0072] At 518, the base station 502 may send an activation command for the TCI state, which is shown as an arrow indicating "RECONFIGURE TCI STATUS FOR CORESET / PUCCH".

[0073] At 520, UE 504 may receive a Reconfigure TCI State Command for CORESET / PUCCH. The command may confirm to UE 504 that the beam direction of the PUCCH and the PUCCH have been recovered.

[0074] exist Figure 5 In the example, the SCell beam recovery process is completed without the assistance of the PCell. Although this method can be used in some example configurations, the method may have some unfavorable characteristics. For example, in this method, dedicated RACH resources may be required on the SCell, associated additional overhead may be generated (e.g., caused by RACH messages and signaling), and / or additional (one or more) RACH priority rules may need to be defined to avoid conflicts between PCell and SCell random access (e.g., when both PCell and SCell are in-band). Although dedicated RACH resources can be used by UE 504 in the case of beam failure recovery, at other times, the dedicated resources are occupied for no reason and cannot be used for other purposes, which is an unfavorable effect. Therefore, it can be appreciated that it is advantageous to have a beam recovery process that can avoid such unfavorable effects.

[0075] Figure 6 600 is a diagram illustrating an example of an SCell beam recovery process with PCell assistance according to one aspect. Figure 6 For purposes of the examples, beam correspondence is assumed (eg, the best receive beam direction is also considered the best transmit beam direction).

[0076] At 610, UE 504 may detect an SCell beam failure. The conditions for determining whether a beam failure has occurred are discussed above and may be used in conjunction with the above. Figure 5 The determination at 610 may be performed in a similar manner as discussed in block 510 of . Upon detection of an SCell beam failure, a beam recovery process may be triggered according to features of the methods described herein.

[0077] At 612, UE 504 may send a scheduling request (SR) to a base station via the PCell (eg, via FR1 corresponding to a sub-6 GHz frequency band), the SR indicating, for example, an upcoming UL transmission.

[0078] After receiving the SR from the UE 504 , at 614 , the base station 502 may send a UL grant to the UE over the PCell for uplink transmission from the UE 504 in response to the SR.

[0079] At 616, the UE 504 may send a message (e.g., MAC-CE) reporting the detected SCell beam / link failure, for example based on the UL grant. In some configurations, the message reporting the detected SCell beam / link failure may further include preferred candidate beam identification information (e.g., beam ID of the preferred beam in the SCell). For example, the UE 504 may be pre-configured with beam IDs for beams monitored for beam recovery purposes, and may periodically monitor downlink beams (e.g., synchronization signal blocks (SSBs) transmitted from the base station 502 via the SCell). Based on measurements of the monitored beams, the UE 504 may identify the preferred candidate beam that is most suitable for reception at the UE 504. In such an example, the UE 504 that has identified the preferred beam candidate may send the beam ID for the preferred beam candidate to the base station 502 via the PCell (e.g., in a MAC-CE).

[0080] The base station 502 may receive a message from the UE 504 through the PCell and may activate an uplink / downlink channel for communicating with the UE 504 through the SCell. The uplink / downlink channel may be associated with the direction of the preferred candidate beam.

[0081] At 618, the base station 502 may send a SCell control resource set (CORESET) TCI state activation signal to the UE 504. The CORESET TCI state activation signal may indicate resources that have been activated by the base station for a control channel associated with the preferred candidate beam.

[0082] At 620, UE 504 may receive a CORESET TCI state activation signal and determine based on the CORESET TCI state activation signal that a control channel associated with a preferred candidate beam in the SCell has been configured and resources for the control channel have been activated. Therefore, UE 504 may consider that a control channel / link in the preferred beam direction has been established (as shown in 621), and thus the beam recovery process has been successfully completed. Figure 6 The example processing shown assumes beam correspondence, so the beam direction on which the UE 504 receives downlink transmissions through the SCell can be used for uplink transmissions through the SCell. In one aspect, the established SCell control channel can be used as a downlink channel as well as an uplink channel (e.g., at different points in time).

[0083] In one example configuration, as an alternative to the operations discussed at 614, the UL report can be triggered via DCI from the base station instead of the UL grant. For example, in response to the SR from the UE 504, the base station 502 can send a DCI, where the DCI can request to send an uplink report (e.g., L1 report) via the PCell. In such an example, at 616, the UE 504 can send an uplink report via the PCell instead of a MAC-CE.

[0084] Figure 7 FIG. 700 is a diagram illustrating an example of an SCell beam recovery process with PCell assistance but without assuming any beam correspondence according to one aspect. Figure 7 The initial processing shown in the example is Figure 6 The initial processing is similar to that shown in , but there is some additional signaling later in the recovery process. Figure 7 In the example beam recovery process of , it is considered that the beam recovery CORESET (the control resource set for beam recovery in the SCell) may not be activated unless there is a need for it, and therefore, the beam recovery resources may not be blocked from being used for other purposes by the base station 502. Therefore, as discussed below, Figure 7 The example beam recovery procedure may help to activate RACH resources for SCell on demand via PCell.

[0085] At 710, UE 504 may detect SCell beam failure. Upon detecting SCell beam failure, a beam recovery procedure may be triggered according to features of the methods described herein.

[0086] At 712, the UE 504 may send a SR to the base station via the PCell (eg, via FR1 corresponding to a sub-6 GHz frequency band), the SR indicating, for example, an upcoming UL transmission.

[0087] After receiving the SR from the UE 504 , at 714 , the base station 502 may send a UL grant to the UE over the PCell for uplink transmission from the UE 504 in response to the SR.

[0088] At 716, UE 504 may send a message (e.g., MAC-CE) over PCell, for example using UL grant, reporting the detected SCell beam / link failure. Base station 502 may receive the message over PCell and may activate beam restoration resources corresponding to SCell for beam restoration.

[0089] At 718, the base station 502 may send a SCell CORESET TCI state activation signal to the UE 504, indicating that the control channel resources (associated with the SCell) for beam recovery have been activated. In some configurations, the SCell CORESET TCI state activation signal may indicate a beam ID and corresponding resources for monitoring a beam from the base station 502 via the SCell, for example, for beam failure recovery operations. In various configurations, based on the beam ID and corresponding resources, the UE 504 may monitor downlink signals (e.g., SSBs and / or other reference signals) via a downlink beam and perform measurements to identify the best downlink beam direction. Based on the measurements, the UE 504 may identify a preferred downlink beam (or beam set) for a directional downlink channel (e.g., PDCCH). In some configurations, the UE 504 may send an indication of the selected / identified preferred downlink beam to the base station 502 via the PCell so that the base station 502 may configure the PDCCH for the UE 504 in the SCell in the preferred downlink beam direction. In some configurations, after the SCell CORESET is activated, the downlink channel(s) associated with the SCell may be considered to have been restored, as shown at block 720 .

[0090] According to an aspect, at 722, the base station 502 may send a PDCCH order on the SCell. The PDCCH order may be defined as a mechanism by which the base station 502 may force (eg, instruct / command) the UE 504 to initiate a RACH procedure. Figure 7 In the given example of , the base station 502 can send a PDCCH command to the UE 504 to initiate a RACH for beam failure recovery. In some configurations, the PDCCH command can include information indicating the following: a resource set associated with the SCell for performing RACH, one or more RACH preamble indexes, one or more beam IDs corresponding to candidate beams for sending RACH preambles, etc. The resource set associated with the SCell may include resources for sending RACH preambles via different candidate beams.

[0091] At 724, the UE 504 may initiate a RACH procedure. For example, initiating the RACH procedure may include the UE 504 sending a RACH preamble on corresponding resources (e.g., time-frequency resources indicated in the PDCCH order) in the SCell via respective candidate beams. In one example, the candidate beams via which the RACH preamble is sent may include respective beams identified by beam IDs indicated in the PDCCH order. In one example, the candidate beams via which the RACH preamble is sent may include one or more beams that may have been identified as preferred candidate beams by the UE 504 based on downlink signal measurements corresponding to signals (e.g., SSBs) received via these beams at an earlier point in time.

[0092] At 726, the base station 502 may send a RACH response (eg, Msg2) to the UE 504 via the SCell. In some configurations, the RACH response may include a timing advance value and / or other additional information for the UE 504 to perform uplink synchronization.

[0093] The RACH response at 726 may be sent in response to a RACH preamble that is sent in a beam direction that may be most suitable for the base station 502 for the purpose of uplink reception. For example, the base station 502 may receive a RACH preamble sent by the UE 504 on their corresponding resources in the SCell via five beams. Of the five beams, the base station 502 may determine which beam is the best beam for the uplink from the perspective of the base station 502. The base station 502 may establish an uplink channel (e.g., PUCCH) on the resources corresponding to the determined best beam (corresponding to the SCell) (it should be understood that there is a one-to-one mapping between the beam direction and the resources on which the beam is sent). As shown in box 727, this is shown as recovery of the uplink channel (e.g., PUCCH) in the SCell.

[0094] At 728, the base station 502 may send a command to reconfigure the TCI state for the PUCCH through the SCell. The command to reconfigure the TCI state may confirm to the UE 504 that the PUCCH has been restored.

[0095] Although not explicitly shown in diagram 700 , the RACH process may involve other signaling between UE 504 and base station 502 (eg, Msg3 and Msg4 ).

[0096] Figure 8 is a diagram 800 illustrating another example of an SCell beam recovery process with PCell assistance according to an aspect. Figure 8 The example beam recovery process shown follows Figure 7The example shown handles a similar mechanism, but in Figure 8 In the example processing of , no UL authorization, MAC-CE signaling, etc. are required. Figure 8 As shown in the example process of , according to one aspect, the base station 502 can issue a special PDCCH order to trigger the initiation of a RACH process for beam recovery, as described below.

[0097] At 810, UE 504 may detect SCell beam failure. Upon detecting SCell beam failure, a beam recovery procedure may be triggered.

[0098] At 812, UE 504 may send a special SR to base station 502 via PCell (e.g., via FR1 corresponding to the sub-6 GHz frequency band). In this example, the scheduling request is referred to as a special SR because the SR is specifically configured for the SCell beam failure recovery process. The special SR may indicate that an SCell beam failure has occurred.

[0099] At 814, in response to receiving the special SR, the base station 502 may send a special PDCCH command, e.g., a specially configured message sent via the PCell, for triggering a RACH process on the SCell for beam failure recovery. In some configurations, the special PDCCH command may include, for example, information indicating: a resource set associated with the SCell for performing RACH, one or more RACH preamble indices, one or more beam IDs corresponding to candidate beams for sending RACH preambles, etc. The resource set associated with the SCell beam recovery may include resources for sending RACH preambles via respective candidate beams (e.g., in a frequency band corresponding to the SCell / FR2).

[0100] In various configurations, based on the beam ID and the corresponding resources, the UE 504 may monitor downlink signals (e.g., SSBs and / or other reference signals) via the downlink beam and perform measurements to identify the best downlink beam direction. Based on the measurements, the UE 504 may identify a preferred downlink beam (or beam set) for a directional downlink channel (e.g., PDCCH). In some configurations, the UE 504 may send an indication of the selected / identified preferred downlink beam to the base station 502 via the PCell so that the base station 502 may configure the PDCCH for the UE 504 in the SCell in the preferred downlink beam direction.

[0101] At 816, the UE 504 may initiate a RACH procedure. For example, initiating the RACH procedure may include the UE 504 sending (through the SCell) a RACH preamble via each candidate beam on corresponding resources (e.g., time-frequency resources indicated in the PDCCH order). In one example, the candidate beams via which the RACH preamble is sent may include each beam identified by a beam ID indicated in the PDCCH order. In one example, the candidate beams via which the RACH preamble is sent may include one or more beams that may have been identified by the UE 504 as preferred candidate beams based on downlink signal measurements corresponding to signals (e.g., SSBs) received via these beams at an earlier point in time.

[0102] The base station 502 may receive a RACH preamble sent by the UE 504 via various candidate beams on their corresponding resources in the SCell. Among these beams, the base station 502 may determine which beam is the best beam for the uplink from the perspective of the base station 502. After determining the best uplink beam for the UE 504, at 818, the base station 502 may send a PDCCH (in the SCell) with a C-RNTI to the UE 504. The response with the C-RNTI sent via the SCell PDCCH may be a RACH response, which may be sent specifically in response to a RACH preamble transmission for beam failure recovery from the UE 504. According to an aspect, the C-RNTI may be mapped to the best beam determined for the UE 504 for an uplink channel (e.g., PUCCH). Therefore, after receiving the response with the C-RNTI from the base station 502, at 819, the UE 504 may be able to determine the best uplink beam that may be most suitable for the uplink channel.

[0103] The base station 502 may establish an uplink channel (e.g., PUCCH) on the resources corresponding to the determined best beam (corresponding to the SCell). As shown in block 820, this is shown as recovery of the uplink channel (e.g., PUCCH) in the SCell. Based on the resource information received earlier in the PDCCH command, the UE 504 may already know the resources corresponding to the best uplink beam, and may therefore know the uplink channel (PUCCH) that the UE 504 will use to send uplink control information.

[0104] After detecting the C-RNTI PDCCH (at 819), the UE 504 may continue to monitor the PDCCH candidates in the search space until the UE 504 may detect a MAC control element (MAC-CE) activation command for a transmission configuration indicator (TCI) state. At 822, the base station 504 may send an activation command for the TCI state, which is shown as an arrow indicating "Reconfigure TCI state PDCCH / PUCCH".

[0105] At 824, the UE 504 may receive a reconfigure TCI state command for PDCCH / PUCCH from the base station 502. The command to reconfigure TCI state may confirm to the UE 504 the preferred / optimal beams for downlink and uplink, and also confirm that the PDCCH / PUCCH has been recovered.

[0106] Fig. 9 is a diagram 900 illustrating yet another example of an SCell beam recovery process with PCell assistance according to an aspect.

[0107] At 910, UE 504 may detect SCell beam failure. Upon detecting SCell beam failure, a beam recovery procedure may be triggered.

[0108] Combined with the above Figure 8 Similar to the example processing discussed in step 812 of , at 912, UE 504 may send a special SR to base station 502 via PCell (e.g., via FR1 corresponding to the sub-6 GHz frequency band). The scheduling request may be an SR specifically configured for the SCell beam failure recovery process, and may provide an indication to the base station via PCell that an SCell beam failure has occurred.

[0109] At 914, in response to receiving the special SR, the base station 502 may send a special PDCCH command, for example, a specially configured message sent via the PCell, to trigger a RACH procedure on the SCell for beam failure recovery. Figure 8 Similar to the special PDCCH command discussed in the example processing of , the special PDCCH command may include, for example, information indicating: a resource set associated with an SCell for performing RACH, one or more RACH preamble indexes, one or more beam IDs corresponding to candidate beams for sending RACH preambles, etc. However, in addition to the above parameters, Fig. 9 The special PDCCH command in the example processing also includes a request for an L1-RSRP report for the SCell downlink beam and / or a request to report a beam ID corresponding to the preferred downlink beam determined by the UE 504.

[0110] In response to the request for the L1-RSRP report for the SCell downlink beam and based on the information related to the beam ID and the corresponding resources, the UE 504 can monitor the downlink signals (e.g., SSB and / or other reference signals) transmitted via the downlink beam and perform measurements to identify the best / preferred downlink beam direction. The UE 504 can generate the L1-RSRP report for the downlink beam based on the measurements. In addition, based on the measurements, the UE 504 can identify the preferred downlink beam (or beam set) for directional downlink channels (e.g., PDCCH).

[0111] At 916, the UE 504 may send a L1-RSRP report of the downlink beam and / or a beam ID corresponding to the determined preferred downlink beam to the base station 502, for example, via the PUCCH in the PCell. In one example, if the UE 504 sends an L1-RSRP report of the downlink beam indicating the RSRP of each of the candidate downlink beams for which measurements are performed, the base station 502 may identify / select the preferred downlink beam based on the received report. In another example, if the UE 504 sends a beam ID corresponding to the preferred downlink beam determined by the UE, the base station 502 may consider the preferred downlink beam determined by the UE as the best downlink beam. In either case, based on the report received via the PUCCH in the PCell, the base station 502 may configure a downlink channel (e.g., PDCCH) corresponding to the preferred downlink beam for the UE 504 in the SCell, as indicated at 918.

[0112] Next, at 920, the UE 504 may perform a RACH procedure by sending (through the SCell) a RACH preamble corresponding to the determined beam (e.g., a preamble ID corresponding to or associated with the beam ID of the determined preferred beam) on a corresponding resource (e.g., a time-frequency resource corresponding to the beam ID of the preferred beam indicated in the PDCCH command). In this case, the UE 504 does not need to send a RACH preamble on all candidate beams, and the base station 502 does not need to monitor / search all such RACH preamble transmissions in different beams to determine the best uplink beam. Instead, since the beam ID of the preferred beam is known to the base station 502, the base station 502 can monitor only the given preferred beam.

[0113] At 922, the base station 502 may send a PDCCH (in the SCell) with a C-RNTI to the UE 504. As previously described, the response with the C-RNTI sent via the SCell PDCCH may be a RACH response, which may be specifically sent in response to a RACH preamble transmission from the UE 504 for beam failure recovery. The C-RNTI in the DCCH may be mapped to the beam ID of the preferred beam. Thus, by using the C-RNTI in the PDCCH, the base station 502 may indicate to the UE 504 the preferred beam for downlink and / or uplink transmission. For example, based on the received C-RNTI in the PDCCH (at 924), the UE 504 may determine the beam ID corresponding to / mapped to the C-RNTI, thereby clarifying the preferred beam for uplink / downlink.

[0114] The base station 502 may establish downlink and uplink channels (PDCCH / PUCCH) on resources corresponding to the determined best beam (corresponding to the SCell). As shown in block 925, this is shown as restoration of downlink / uplink channels in the SCell.

[0115] At 926, the base station 504 may send (in the SCell) an activation command for the TCI state, which is shown as an arrow indicating "RECONFIGURE TCI STATUS PDCCH / PUCCH".

[0116] At 928, the UE 504 may receive a reconfigure TCI state command for PDCCH / PUCCH from the base station 502. The command to reconfigure the TCI state may confirm the preferred / optimal beam to the UE 504 and also confirm that the PDCCH / PUCCH has been recovered.

[0117] Although respectively Figure 8 and Fig. 9 Not explicitly shown in Figures 800 and 900 , however, the RACH process may involve other signaling (eg, Msg2, Msg3, and Msg4) between the UE 504 and the base station 502.

[0118] Fig.101000 is a flow chart of an example method of wireless communication related to SCell beam failure recovery with PCell assistance, wherein beam correspondence is assumed. The method can be performed by a UE (e.g., UE 104, 350, 404, 504, 1302 / 1302', 1750; UE SCell beam recovery component 198; processing system 1414, which can include memory 360 and can be the entire UE 350 or a component of UE 350, such as RC processor 356, TX processor 368 and / or controller / processor 359). The method can improve the beam recovery process. Optional aspects are shown in dashed lines.

[0119] At 1002, the UE may detect a secondary cell (SCell) beam failure. For example, as discussed above (e.g., in conjunction with Figure 6 and elsewhere), the UE 504 may determine that the RSRP corresponding to one or more beams of the SCell falls below a threshold. In some configurations, such a determination may be considered an SCell beam failure. For example, the beam failure determination component 1306 of the apparatus 1302 may detect an SCell beam failure.

[0120] At 1004, the UE may send an SR to the base station via the primary cell (PCell) in response to detecting an SCell beam failure. Figure 6 As discussed, detection of an SCell beam failure may trigger beam failure recovery processing, and a UE (e.g., UE 504) may send an SR to base station 502, as described in connection with 612. For example, SR component 1308 of apparatus 1302 may trigger transmission of an SR in response to detection of an SCell beam failure.

[0121] At 1006, the UE may receive a first message from the base station via the PCell, the first message including one of a UL grant or a trigger for a UL report. Figure 6 In some embodiments, the UE 504 may receive a UL grant from the base station 502 in response to the transmitted SR. Alternatively, in some configurations, the UE 504 may instead receive a DCI requesting an L1 beam report (e.g., a beam report indicating an RSRP of a downlink beam) from the UE 504. For example, the trigger component 1312 of the apparatus 1302 may receive (one or more) signals via the PCell, the signal including a first message including a UL grant or a trigger for a UL report.

[0122] At 1008, the UE may send a second message to the base station via the PCell, the second message including information indicating a SCell beam failure. Figure 6In the example process of , in response to the uplink grant, the UE 504 can send a MAC-CE reporting the SCell beam failure to the base station 502. In another example, the UE 504 can send the requested L1 report to the base station 502. For example, the beam failure reporting component 1314 of the device 1302 can cause the device 1302 to send a message including information indicating the SCell beam failure.

[0123] In one configuration, the second message further identifies a preferred candidate beam associated with the SCell. Figure 6 As discussed elsewhere, in some configurations, the UE 504 may indicate to the base station 502 the identified optimal downlink beam that is most suitable (from the UE's perspective) for downlink reception. Given that the second message identifies the preferred candidate beam associated with the SCell, at 1010, the UE may receive a SCell CORESET TCI state activation signal from the base station via the PCell, the signal corresponding to the preferred candidate beam associated with the SCell. For example, referring to Figure 6 , the UE 504 may receive (at 620) a SCell CORESET TCI state activation signal from the base station 502, indicating that a control channel corresponding to the preferred beam has been activated on resources corresponding to the preferred beam. The resources corresponding to the preferred beam may be pre-configured and known to the UE 504, or otherwise communicated to the UE 504 from the base station 502. For example, the CORESET component 1316 of the apparatus 1302 may receive the SCell CORESET TCI state activation signal.

[0124] At 1012, based on the CORESET TCI state activation signal, the UE may determine a control channel associated with a preferred candidate beam for communicating with the base station. Figure 6 In the case of the example process shown and discussed above), the same control channel and preferred beam can be used for uplink and downlink control links. For example, the beam determination component 1318 of the device 1302 can determine the control channel associated with the preferred candidate beam.

[0125] Fig.111100 is a flowchart of another example method of wireless communication related to SCell beam failure recovery with PCell assistance, in which no beam correspondence is assumed. The method can be performed by a UE (e.g., UE 104, 350, 404, 504, 1302 / 1302', 1750; UE SCell beam recovery component 198; processing system 1414, which can include memory 360 and can be the entire UE 350 or a component of UE 350, such as RC processor 356, TX processor 368 and / or controller / processor 359). The method can improve the beam recovery process. Optional aspects are shown in dashed lines.

[0126] At 1102, the UE may detect a secondary cell (SCell) beam failure. For example, as discussed above (e.g., in conjunction with Figure 7 and elsewhere), the UE 504 may determine that the RSRP corresponding to one or more beams of the SCell falls below a threshold. In some configurations, such a determination may be considered an SCell beam failure. For example, the beam failure determination component 1306 of the apparatus 1302 may detect an SCell beam failure.

[0127] At 1104, the UE may send an SR to the base station via the primary cell (PCell) in response to detecting an SCell beam failure. Figure 7 As discussed, detection of an SCell beam failure may trigger beam failure recovery processing, and a UE (e.g., UE 504) may send an SR to base station 502, as described in connection with 712. For example, SR component 1308 of apparatus 1302 may trigger transmission of an SR in response to detection of an SCell beam failure.

[0128] At 1106, the UE may receive a first message from the base station via the PCell, the first message including one of a UL grant or a trigger for a UL report. Figure 7 In response to the transmitted SR, UE 504 may receive a UL grant from base station 502. For example, trigger component 1312 of apparatus 1302 may receive (one or more) signals via PCell, the signals including a first message including a UL grant or a trigger for UL reporting.

[0129] At 1108, the UE may send a second message to the base station via the PCell, the second message including information indicating a SCell beam failure. Figure 7In the example process of , in response to the uplink grant, the UE 504 can send a MAC-CE reporting the SCell beam failure to the base station 502. For example, the beam failure reporting component 1314 of the device 1302 can cause the device 1302 to send a message including information indicating the SCell beam failure.

[0130] At 1110, the UE may receive a CORSET TCI state activation signal from the base station via the PCell, the signal indicating activation of a resource set associated with the SCell. Figure 7 , the UE 504 may receive (at 719) a SCell CORESET TCI state activation signal from the base station 502, which indicates activation of a resource set associated with the SCell. The CORESET TCI state activation signal may indicate a resource set associated with the SCell that may be used to monitor / search for a downlink beam from the base station 502, a beam ID of a candidate beam that may be searched / monitored, a monitoring period, etc. For example, the CORESET component 1316 of the apparatus 1302 may receive the SCell CORESET TCI state activation signal.

[0131] Based on the SCell CORESET TCI state activation signal, the UE may perform downlink beam measurements and identify a preferred beam (or preferred beam set) based on the measurements (e.g., the beam with the highest RSRP). At 1112, the UE may determine a downlink channel corresponding to the identified preferred downlink beam based on a mapping of corresponding resources. For example, the beam determination component 1318 of the device 1302 may determine a downlink channel associated with a preferred candidate beam.

[0132] At 1114, the UE may receive a PDCCH command from the base station, which triggers a RACH procedure, for example, for beam failure recovery, such as in conjunction with Figure 7 discussed at 722. As discussed above, the PDCCH order can indicate a preamble ID for the RACH, resources for sending the RACH preamble, corresponding beam IDs via which the RACH preamble can be sent, etc. For example, the PDCCH component 1320 of the apparatus 1302 can receive the PDCCH order.

[0133] At 1116, the UE may perform a RACH procedure based on the PDCCH order. Figure 7 , the UE 504 may send (at 724) a RACH preamble via the candidate beam, thereby initiating a RACH procedure. The UE 504 may send the RACH preamble via each beam based on the PDCCH command. For example, the RACH component 1322 of the apparatus 1302 may perform the RACH procedure.

[0134] As discussed above, the base station 502 can search for beam transmissions carrying RACH preambles from the UE 504 and identify the best uplink beam. The base station can then send a message (e.g., a RACH response) to the UE 504 that includes information indicating the identified best beam (e.g., as a C-RNTI PDCCH in the SCell).

[0135] At 1118, the UE may determine the uplink beam associated with the SCell based on the RACH process. Figure 7 , UE 504 can determine the optimal uplink beam associated with the SCell based on the RACH response from base station 502. For example, beam determination component 1318 can determine the uplink beam.

[0136] Fig.12 1200 is a flowchart of another example method of wireless communication related to SCell beam failure recovery with PCell assistance. The method can be performed by a UE (e.g., UE 104, 350, 404, 504, 1302 / 1302', 1750; UE SCell beam recovery component 198; processing system 1414, which can include memory 360 and can be the entire UE 350 or a component of UE 350, such as RC processor 356, TX processor 368 and / or controller / processor 359). The method can improve the beam recovery process. Optional aspects are shown in dashed lines.

[0137] At 1202, the UE may detect a secondary cell (SCell) beam failure. For example, as discussed above (e.g., in conjunction with Figure 8 and elsewhere), the UE 504 may determine that the RSRP corresponding to one or more beams of the SCell has dropped below a threshold and may regard this condition as an SCell beam failure. For example, the beam failure determination component 1306 of the device 1302 may detect an SCell beam failure.

[0138] At 1204, the UE may send a special SR including information indicating a SCell beam failure to the base station via the primary cell (PCell). Figure 8 As discussed, detection of an SCell beam failure may trigger beam failure recovery processing, and a UE (e.g., UE 504) may send a specially configured SR to the base station 502 to indicate the SCell beam failure, as described in conjunction with 812. For example, the SR component 1308 of the apparatus 1302 may trigger the sending of a special SR in response to detection of an SCell beam failure.

[0139] At 1206, the UE may receive a physical downlink control channel (PDCCH) command via the PCell and in response to the special SR, the PDCCH command indicating a resource set associated with the SCell. Figure 8 In response to the transmitted special SR, the UE 504 may receive a special PDCCH command from the base station 502 through the PCell. The PDCCH command may include one or more of the following: a beam identifier (ID) corresponding to a beam set, a preamble index for a RACH process, and information indicating a resource set (e.g., for monitoring / searching each downlink beam, for sending a PRACh, etc.). For example, the PDCCH component 1320 of the apparatus 1302 may receive the PDCCH command.

[0140] At 1208, the UE may determine a downlink beam corresponding to a downlink control channel associated with the SCell based on the information received in the PDCCH order. Figure 8 In an example process of , UE 504 can monitor downlink beams, perform measurements to determine quality metrics (e.g., RSSRP / RSRQ / SINR, etc.) of the monitored beams, and identify one or more downlink beams that are most suitable for downlink reception (e.g., based on the measurements). For example, beam determination component 1318 of device 1302 can determine the downlink beams.

[0141] At 1210, the UE may perform a RACH process in response to a PDCCH command based on a resource set associated with the SCell, wherein performing the RACH process may include sending a first message via each beam in the beam set, the first message including a RACH preamble indicated in the PDCCH command. Thus, in some configurations, the UE 504 may send a RACH preamble via each beam based on the PDCCH command. In some configurations, the UE 504 may send a RACH preamble via one or more beams that have been identified at an earlier time as corresponding to the best reception direction. For example, the UE 504 may send a first message via the same beam that has been identified as a preferred downlink beam. For example, the RACH component 1322 of the device 1302 may perform a RACH process.

[0142] At 1212, the UE may receive a second message including a C-RNTI via a PDCCH associated with the SCell in response to the first message, wherein the C-RNTI may correspond to a beam in the beam set. For example, the C-RNTI in the received PDCCH may be mapped to a beam ID corresponding to a beam via which the UE 504 earlier sent a RACH preamble. For example, the PDCCH component 1320 may receive the second message including the C-RNTI.

[0143] At 1214, the UE may determine an uplink beam corresponding to an uplink control channel associated with the SCell based on the second message. Figure 8 , UE 504 can determine the optimal uplink beam associated with the SCell based on the PDCCH with C-RNTI from base station 502. For example, beam determination component 1318 can determine the uplink beam.

[0144] Fig.13 1300 is a conceptual data flow diagram illustrating data flow between different parts / components in an example apparatus 1302 in communication with a device 1350. The apparatus may be a UE. The apparatus may perform the methods of flowcharts 1000, 1100, and / or 1200. In one configuration, the apparatus 1302 may include a receiving component 1304, a beam failure detection component 1306, an SR component 1308, a transmitting component 1310, a triggering component 1312, a beam failure reporting component 1314, a CORESET component 1316, a beam determination component 1318, a PDCCH component 1320, and a RACH component 1322. The apparatus 1302 may include a method that may perform the above in combination with Figures 5 to 12 The apparatus 1350 (eg, a base station) may include the same components as those shown with respect to the apparatus 1302 and in conjunction with the following. Fig.17 and / or Fig.18 The components discussed are the same or similar components. It should be understood that in other examples, the apparatus 1302 may be a base station and the device 1350 may be a UE.

[0145] Receiving component 1304 may be configured to receive various types of signals / messages and / or other information from other devices including device 1350. Messages / information may be received via receiving component 1304 and provided to one or more components of apparatus 1302 for further processing and use in performing various operations.

[0146] The beam failure detection component 1306 can be configured to determine an SCell beam failure and trigger a beam failure recovery mechanism (eg, as described in conjunction with any of 1002 , 1102 , and / or 1202 ).

[0147] The SR component 1308 can be configured to trigger the transmission of the SR in response to detecting an SCell beam failure (eg, as described in connection with any of 1004 , 1104 , and / or 1204 ).

[0148] According to various aspects described herein, the sending component 1310 can be configured to send signals to one or more external devices, including, for example, the device 1350. In various configurations, the signals and / or information can be transmitted by the sending component 1310 according to the methods discussed above (including Figures 10 to 12 Flowchart method) to send.

[0149] The triggering component 1312 may be configured to receive, via the PCell, signal(s) comprising a first message comprising a UL grant or a trigger for UL reporting (eg, as described in connection with any of 1006 and / or 1106).

[0150] The beam failure reporting component 1314 can be configured to cause the sending of a message that includes information indicating an SCell beam failure (e.g., as described in conjunction with any of 1008 and / or 1108).

[0151] The CORESET component 1316 may be configured to receive and process CORESET signals such as the SCell CORESET TCI state activation signal (eg, as described in connection with any of 1010 and / or 1110 ).

[0152] The beam determination component 1318 can be configured to determine a preferred candidate beam, a control channel associated with a preferred candidate beam, a downlink channel associated with a preferred candidate beam, an uplink beam associated with an SCell, a downlink beam corresponding to a downlink control channel associated with the SCell, and / or an uplink beam corresponding to an uplink control channel associated with the SCell (e.g., as described in conjunction with any one of 1012, 1112, 1118, 1208 and / or 1214).

[0153] The PDCCH component 1320 can be configured to receive a PDCCH command and / or a C-RNTI (eg, as described in connection with any of 1114, 1206, and / or 1212).

[0154] RACH component 1322 can be configured to perform RACH procedures (e.g., as described in connection with any of 1116 and / or 1210).

[0155] The device may include performing the above Figures 10 to 12The flowchart of each block of the algorithm is appended. Figures 10 to 12 Each block in the flowchart of can be performed by a component, and the apparatus may include one or more of those components. These components may be one or more hardware components that are specifically configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium to be implemented by a processor, or some combination thereof.

[0156] Fig.14 1400 is a diagram illustrating an example of a hardware implementation for an apparatus 1302' employing a processing system 1414. The processing system 1414 may be implemented with a bus architecture, which is generally represented by a bus 1424. The bus 1424 may include any number of interconnecting buses and bridges, depending on the specific application and overall design constraints of the processing system 1414. The bus 1424 links together various circuits including one or more processors and / or hardware components (represented by the processor 1404, components 1304, 1306, 1308, 1310, 1312, 1314, 1316, 1318, 1320, 1322, and computer readable medium / memory 1406). The bus 1424 may also link various other circuits, such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art and are not described in detail.

[0157] The processing system 1414 may be coupled to the transceiver 1410. The transceiver 1410 is coupled to one or more antennas 1420. The transceiver 1410 provides components for communicating with various other devices over a transmission medium. The transceiver 1410 receives signals from the one or more antennas 1420, extracts information from the received signals, and provides the extracted information to the processing system 1414, in particular the receiving component 1304. In addition, the transceiver 1410 receives information from the processing system 1414 (in particular the transmitting component 1310), and based on the received information, generates a signal to be applied to the one or more antennas 1420. The processing system 1414 includes a processor 1404 coupled to a computer-readable medium / memory 1406. The processor 1404 is responsible for general processing, including executing software stored on the computer-readable medium / memory 1406. When executed by the processor 1404, the software causes the processing system 1414 to perform the various functions described above for any particular device. The computer-readable medium / memory 1406 may also be used to store data that is manipulated by the processor 1404 when executing software. The processing system 1414 also includes at least one of the components 1304, 1306, 1308, 1310, 1312, 1314, 1316, 1318, 1320, 1322. The component may be a software component that runs in the processor 1404 and resides / stored in the computer-readable medium / memory 1406, one or more hardware components coupled to the processor 1404, or some combination thereof. The processing system 1414 may be a component of the UE 350 and may include the memory 360, and / or at least one of the TX processor 368, the RX processor 356, and the controller / processor 359. Alternatively, the processing system 1414 may be the entire UE (e.g., see Figure 3 of 350).

[0158] In one configuration, an apparatus 1302 / 1302' for wireless communication includes a component for detecting a secondary cell (SCell) beam failure; a component for sending a scheduling request (SR) to a base station via a primary cell (PCell) in response to detecting the SCell beam failure; a component for receiving a first message from the base station via the PCell, the first message including one of an uplink (UL) grant or a trigger for an UL report; a component for sending a second message to the base station via the PCell, the second message including information indicating the SCell beam failure; a component for receiving a control resource set (CORESET) transmission configuration indicator (TCI) state activation signal for a preferred candidate beam associated with the SCell from the base station via the PCell; and a component for transmitting a control resource set (CORESET) transmission configuration indicator (TCI) state activation signal based on the CORESET A component for determining a control channel associated with a preferred candidate beam for communicating with a base station by transmitting a TCI state activation signal; a component for receiving a control resource set (CORESET) transmission configuration indicator (TCI) state activation signal from a base station via a PCell, the signal indicating activation of a resource set associated with an SCell; a component for determining a downlink beam associated with an SCell based on the resource set associated with the SCell; a component for receiving a physical downlink control channel (PDCCH) command via a downlink control channel associated with the SCell; a component for performing a random access channel (RACH) procedure in response to a PDCCH command; a component for determining an uplink beam associated with an SCell based on the RACH procedure; a component for performing a RACH procedure based on the resource set associated with the SCell; a component for determining an uplink beam associated with an SCell based on a confirmation message from a base station; a component for communicating with a PCell using a frequency band below 6 GHz; a component for communicating with an SCell using a millimeter wave (mmW) frequency band; a component for detecting a secondary cell (SCell) beam failure; a component for sending a scheduling request (SR) to a base station via a primary cell (PCell), the SR including information indicating a SCell beam failure; a component for receiving, in response to the SR, a physical downlink control channel (PDCCH) command from a base station via the PCell indicating a resource set associated with the SCell; a component for determining a downlink beam corresponding to a downlink control channel associated with the SCell based on the PDCCH command; a component for performing a RACH process in response to the PDCCH command based on the resource set associated with the SCell, wherein performing the RACH process includes sending a first message via each beam in the beam set, the first message including a RACH preamble indicated in the PDCCH command;A component for receiving, in response to a first message, a second message from a base station via a PDCCH associated with the SCell, the second message including a cell-radio network temporary identifier (C-RNTI), wherein the C-RNTI corresponds to a beam in a beam set; and a component for determining, based on the second message, an uplink beam corresponding to an uplink control channel associated with the SCell. The aforementioned components may be one or more of the aforementioned components of the processing system 1414 of the device 1302 and / or the device 1302', which are configured to perform the functions described by the aforementioned components. As described above, the processing system 1414 may include a TX processor 368, an RX processor 356 and / or a controller / processor 359. Thus, in one configuration, the aforementioned components may be a TX processor 368, an RX processor 356 and / or a controller / processor 359, which are configured to perform the functions described by the aforementioned components. Alternatively, the processing system 1414 may be the entire UE (e.g., see; Figure 3 of 350).

[0159] Fig.15 1500 is a method of wireless communication. The method may be performed by a base station (e.g., base station 102, 180, 310, 402, 502, 1702 / 1702', 1350; base station SCell beam recovery component 199; processing system 1414, which may include memory 376 and may be the entire base station 310 or a component of the base station 310, such as TX processor 316, RX processor 370 and / or controller / processor 375). The method may improve the beam recovery process. Optional aspects are shown in dashed lines.

[0160] In 1502, the base station receives an SR from the UE via the PCell based on detecting an SCell beam failure at the UE. For example, the SR component 1706 of the apparatus 1702 may receive the SR from the UE.

[0161] In 1504, the base station sends a first message from the PCell to the UE, the first message including one of an uplink grant or a trigger for UL reporting. For example, the trigger component 1708 of the device 1702 can cause the device 1702 to send the first message including one of an uplink grant or a trigger for UL reporting.

[0162] In 1506, the base station receives a second message from the UE at the PCell, the second message including information indicating a SCell beam failure. The second message may include one of a MAC-CE or a UL report. The second message may also identify a preferred candidate beam associated with the SCell. For example, the beam failure reporting component 1710 of the device 1702 may receive a message including information indicating a SCell beam failure. In this example, in 1508, the base station may send a CORESET TCI state activation signal for the preferred candidate beam associated with the SCell from the PCell. The CORESET TCI state activation signal may indicate that resources for a control channel associated with the preferred candidate beam have been activated by the base station. The control channel may be used for both uplink control transmissions and downlink control transmissions. For example, the CORESET component 1712 of the device 1702 may cause the device 1702 to send a CORESET TCI state activation signal for the preferred candidate beam associated with the SCell.

[0163] As shown in 1510, the base station may send a CORSET TCI state activation signal from the PCell indicating activation of a resource set associated with the SCell. The CORESET TCI state activation signal may indicate a resource set associated with the SCell. For example, the CORESET component 1712 of the apparatus 1702 may cause the apparatus 1702 to send a CORESET TCI state activation signal indicating activation of a resource set associated with the SCell.

[0164] In an example in which the SCell is provided at a base station, the base station may also send a PDCCH command via a downlink control channel associated with the SCell. For example, the PDCCH component 1714 of the device 1702 may cause the device 1702 to send a PDCCH command. The base station may receive a RACH message via the SCell in response to the PDCCH command, wherein the uplink beam associated with the SCell is determined by the UE based on the RACH process with the SCell. In other examples, the SCell may be at different base stations, and such transmission and reception via the SCell may occur from different base stations. The RACH process may be performed based on a resource set associated with the SCell. For example, the RACH component 1716 of the device 1702 may perform the RACH process. The base station may send a confirmation message to the UE, wherein the uplink beam associated with the SCell is determined by the UE based on a confirmation message from the base station. For example, the confirmation component 1718 of the device 1702 may cause the device 1702 to send a confirmation message.

[0165] PCell can communicate with UE using sub-6 GHz frequency bands, while SCell can communicate with UE using mmW frequency bands.

[0166] Fig.16 1600 is a method of wireless communication. The method may be performed by a base station (e.g., base station 102, 180, 310, 402, 502, 1702 / 1702', 1350; base station SCell beam recovery component 199; processing system 1414, which may include memory 376 and may be the entire base station 310 or a component of the base station 310, such as TX processor 316, RX processor 370 and / or controller / processor 375). The method may improve the beam recovery process. Optional aspects are shown in dashed lines.

[0167] In 1602, the base station receives an SR including information indicating SCell beam failure from a UE via a PCell. For example, an SR component 1706 of the apparatus 1702 may receive the SR from the UE.

[0168] In 1604, the base station sends a PDCCH command from the PCell indicating a resource set associated with the SCell in response to the SR. The PDCCH command may include one or more of the following: a beam identifier (ID) corresponding to the beam set, a preamble index for the RACH process, and information indicating the resource set. The PDCCH command may enable the UE to determine a downlink beam corresponding to a downlink control channel associated with the SCell based on the PDCCH command. For example, the PDCCH component 1714 of the device 1702 may enable the device 1702 to send the PDCCH command.

[0169] In 1606, the base station may receive a first message from the UE at the SCell via each of the beam sets in response to the PDCCH command based on the resource set associated with the SCell, the first message including the RACH preamble indicated in the PDCCH command. For example, the RACH component 1716 of the device 1702 may receive the RACH preamble.

[0170] In 1608, the base station may, in response to the first message, send a second message including a C-RNTI via a PDCCH associated with the SCell, wherein the C-RNTI corresponds to a beam in the beam set, wherein the UE determines an uplink beam corresponding to an uplink control channel associated with the SCell based on the second message. For example, the PDCCH component 1714 may cause the device 1702 to send the C-RNTI via a PDCCH associated with the SCell. In an example where the SCell and the PCell are provided by different base stations, the execution of the PRACH and the sending of the PDCCH in 1606, 1608 may be performed by different base stations.

[0171] Fig.17 1700 is a conceptual data flow diagram illustrating the data flow between different parts / components in an example apparatus 1702. The apparatus may be a base station. The apparatus includes a receiving component 1704, an SR component 1706, a triggering component 1708, a beam failure component 1710, a CORESET component 1712, a PDCCH component 1714, a RACH component 1716, and an acknowledgment component 1718. The apparatus 1702 may include a method for performing the above combined Fig.15 and / or Fig.16 The device 1750 (eg, UE) may include the additional components described with respect to the apparatus 1302 and in conjunction with the following. Figures 5 to 9 , Fig.17 and / or Fig.18 The components discussed are the same or similar components. It should be understood that in other examples, the apparatus 1702 may be a UE and the device 1750 may be a base station.

[0172] Receiving component 1704 may be configured to receive various types of signals / messages and / or other information from other devices including device 1750. Messages / information may be received via receiving component 1704 and provided to one or more components of apparatus 1702 for further processing and use in performing various operations.

[0173] The SR component 1706 can be configured to receive a SR (eg, as described in connection with 1502 and / or 1602) from a UE (eg, device 1750).

[0174] Triggering component 1708 can be configured to cause transmission of a first message including one of an uplink grant or a trigger for UL reporting (eg, as described in conjunction with 1504).

[0175] The beam failure component 1710 can be configured to receive a message including information indicating an SCell beam failure (eg, as described in conjunction with 1506).

[0176] The CORESET component 1712 can be configured to cause the transmission of a CORESET signal, such as a CORESET TCI state activation signal for a preferred candidate beam associated with the SCell and / or a CORESET TCI state activation signal indicating activation of a resource set associated with the SCell (e.g., as described in conjunction with 1508 and / or 1510).

[0177] The PDCCH component 1714 may be configured to cause transmission of a PDCCH command (eg, as described in connection with 1604).

[0178] RACH component 1716 can be configured to receive a RACH preamble and / or perform a RACH procedure (e.g., as described in connection with 1606 and / or 1608).

[0179] The confirmation component 1718 can be configured to cause the transmission of a confirmation message to the UE, wherein the uplink beam associated with the SCell is determined by the UE based on the confirmation message from the base station.

[0180] According to various aspects described herein, the sending component 1720 can be configured to send signals to one or more external devices, including, for example, the device 1750. In various configurations, the signals and / or information can be transmitted by the sending component 1720 according to the methods discussed above (including Fig.15 and / or Fig.16 Flowchart method) to send.

[0181] The device may include performing the above Fig.15 and / or Fig.16 The flowchart of each block of the algorithm is appended. Fig.15 and / or Fig.16 Each block in the flowchart of can be performed by a component, and the apparatus may include one or more of those components. These components may be one or more hardware components that are specifically configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium to be implemented by a processor, or some combination thereof.

[0182] Fig.181800 is a diagram illustrating an example of a hardware implementation for an apparatus 1702' employing a processing system 1814. The processing system 1814 may be implemented with a bus architecture, which is generally represented by a bus 1824. The bus 1824 may include any number of interconnecting buses and bridges, depending on the specific application and overall design constraints of the processing system 1814. The bus 1824 links together various circuits including one or more processors and / or hardware components (represented by the processor 1804, components 1704, 1706, 1708, 1710, 1712, 1714, 1716, 1718, 1720, and computer readable medium / memory 1806). The bus 1824 may also link various other circuits, such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art and are not described in detail.

[0183] The processing system 1814 may be coupled to the transceiver 1810. The transceiver 1810 is coupled to one or more antennas 1820. The transceiver 1810 provides a means for communicating with various other devices over a transmission medium. The transceiver 1810 receives signals from the one or more antennas 1820, extracts information from the received signals, and provides the extracted information to the processing system 1814, in particular the receiving component 1704. In addition, the transceiver 1810 receives information from the processing system 1814 (in particular the transmitting component 1720), and based on the received information, generates a signal to be applied to the one or more antennas 1820. The processing system 1814 includes a processor 1804 coupled to a computer-readable medium / memory 1806. The processor 1804 is responsible for general processing, including executing software stored on the computer-readable medium / memory 1806. When executed by the processor 1804, the software causes the processing system 1814 to perform the various functions described above for any particular device. The computer-readable medium / memory 1806 may also be used to store data that is manipulated by the processor 1804 when executing software. The processing system 1814 also includes at least one of the components 1704, 1706, 1708, 1710, 1712, 1714, 1716, 1718, 1720. The component may be a software component that runs in the processor 1804 and resides / stored in the computer-readable medium / memory 1806, one or more hardware components coupled to the processor 1804, or some combination thereof. The processing system 1814 may be a component of the base station 310, and may include the memory 376, and / or at least one of the TX processor 316, the RX processor 370, and the controller / processor 375. Alternatively, the processing system 1814 may be the entire base station (e.g., see Figure 3 310).

[0184] In one configuration, an apparatus 1702 / 1702′ for wireless communication includes a component for receiving a scheduling request (SR) from a user equipment (UE) via a primary cell (PCell) based on detecting a secondary cell (SCell) beam failure at the UE; a component for sending a first message from the PCell to the UE, the first message including one of an uplink (UL) grant or a trigger for an UL report; a component for receiving a second message from the UE at the PCell, the second message including information indicating the SCell beam failure; and a component for sending control information for a preferred candidate beam associated with the SCell from the PCell. A component for transmitting a control resource set (CORESET) transmission configuration indicator (TCI) state activation signal from a PCell; a component for transmitting a control resource set (CORESET) transmission configuration indicator (TCI) state activation signal from a PCell, the signal indicating activation of a resource set associated with an SCell; a component for transmitting a physical downlink control channel (PDCCH) command via a downlink control channel associated with the SCell; a component for receiving a random access channel (RACH) message via the SCell in response to the PDCCH command, wherein an uplink beam associated with the SCell is activated by the UE based on the SCell l RACH process determined by the SCell; a component for performing the RACH process based on the resource set associated with the SCell; a component for sending a confirmation message to the UE, wherein the uplink beam associated with the SCell is determined based on the confirmation message from the base station; a component for receiving a scheduling request (SR) from a user equipment (UE) via a primary cell (PCell), the SR including information indicating a secondary cell (SCell) beam failure; a component for sending a physical downlink control channel (PDCCH) command from the PCell in response to the SR, the PDCCH command indicating the resource set associated with the SCell ; a component for receiving a first message from a UE at a SCell via each of a beam set in response to a PDCCH command based on a resource set associated with the SCell, the first message including a RACH preamble indicated in the PDCCH command; and a component for sending a second message via a PDCCH associated with the SCell in response to the first message, the second message including a cell-radio network temporary identifier (C-RNTI), wherein the C-RNTI corresponds to a beam in the beam set, wherein the UE determines an uplink beam corresponding to an uplink control channel associated with the SCell based on the second message. The aforementioned components may be one or more of the aforementioned components of the processing system 1814 of the device 1702 and / or the device 1702', which are configured to perform the functions described by the aforementioned components. As described above, the processing system 1814 may include a TX processor 316, an RX processor 370, and a controller / processor 375.Thus, in one configuration, the aforementioned components may be the TX processor 316, the RX processor 370 and / or the controller / processor 375, which are configured to perform the functions recited by the aforementioned components. Alternatively, the processing system 1814 may be the entire base station (eg, see. Figure 3 Base station 310).

[0185] It should be understood that the specific order or hierarchy of the blocks in the disclosed process / flowchart is merely an illustration of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of the blocks in the process / flowchart can be rearranged. In addition, some blocks can be merged or omitted. The attached method claims provide the elements of each block in a sample order, but are not meant to be limited to the specific order or hierarchy provided.

[0186] The foregoing description is provided so that any person skilled in the art can implement the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein, but should be given the full scope consistent with the content expressed by the claims, wherein, unless explicitly stated so, the elements mentioned in the singular form are not intended to mean "one and only one", but "one or more". The word "exemplary" used herein means "as an example, instance or illustration". Any aspect described as "exemplary" herein need not be interpreted as being preferred to other aspects or having advantages over other aspects. Unless otherwise explicitly stated, the term "some" refers to one or more. Combinations such as "at least one of A, B or C", "one or more of A, B or C", "at least one of A, B and C", "one or more of A, B and C" and "A, B, C or any combination thereof" include any combination of A, B and / or C, and may include multiples of A, multiples of B or multiples of C. Specifically, combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof" may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, wherein any such combination may include one or more members or several members of A, B, or C. All structural and functional equivalents of the elements of the various aspects described throughout the present disclosure, which are known or later become known to a person of ordinary skill in the art, are expressly incorporated herein by reference and are intended to be included by the claims. In addition, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly stated in the claims. The words "module," "mechanism," "element," "device," and the like may not be substitutes for the word "component." Thus, no claim element will be interpreted as a component plus unit unless the element is explicitly stated using the phrase "component for..."

Claims

1. A method for wireless communication at a user equipment UE, comprising: Detecting SCell beam failure in the secondary cell; In response to detecting the SCell beam failure, sending a scheduling request SR to the base station via the primary cell PCell; receiving a first message from the base station via the PCell, the first message including one of an uplink (UL) grant or a trigger for UL reporting; Sending a second message to the base station via the PCell and based on the trigger, the second message including information indicating a beam failure of the SCell; and After receiving a downlink indication that control channel resources corresponding to the SCell are activated for beam recovery, a physical downlink control channel (PDCCH) order is received from the base station via the SCell.

2. The method according to claim 1, wherein: The second message includes one of a Medium Access Control-Control Element MAC-CE or the UL report.

3. The method according to claim 1, wherein: The second message further identifies a preferred candidate beam associated with the SCell, and the method further includes: receiving a control resource set CORESET transmission configuration indicator TCI state activation signal for the preferred candidate beam associated with the SCell from the base station via the PCell; and Based on the CORESET TCI state activation signal, a control channel associated with the preferred candidate beam for communicating with the base station is determined.

4. The method according to claim 3, wherein: The CORESET TCI state activation signal indicates that resources for the control channel associated with the preferred candidate beam have been activated by the base station.

5. The method according to claim 3, wherein: The control channel is used for both uplink control transmission and downlink control transmission.

6. The method according to claim 1, further comprising: receiving a control resource set CORESET transmission configuration indicator TCI state activation signal from the base station via the PCell, the signal indicating activation of a resource set associated with the SCell; and Based on the resource set associated with the SCell, a downlink beam associated with the SCell is determined.

7. The method according to claim 6, wherein: The CORESET TCI state activation signal indicates the resource set associated with the SCell.

8. The method according to claim 6, further comprising: Receiving a physical downlink control channel (PDCCH) command via a downlink control channel associated with the SCell; In response to the PDCCH command, performing a random access channel RACH process; and Based on the RACH process, an uplink beam associated with the SCell is determined.

9. The method according to claim 8, wherein: The RACH process is performed based on the resource set associated with the SCell; and The uplink beam associated with the SCell is determined based on a confirmation message from the base station.

10. The method according to claim 1, wherein: The UE communicates with the PCell using a frequency band below 6 GHz and communicates with the SCell using a millimeter wave (mmW) frequency band.

11. A method for wireless communication at a user equipment UE, comprising: Detecting SCell beam failure in the secondary cell; Sending a scheduling request SR to a base station via a primary cell PCell, where the SR includes information indicating a beam failure of the SCell; and In response to the SR, receiving a physical downlink control channel (PDCCH) order from the base station via the PCell indicating a resource set associated with the SCell, The physical downlink control channel command includes a request for an L1-RSRP report of the SCell downlink beam and / or a request for reporting a beam ID corresponding to a preferred downlink beam determined by the UE.

12. The method according to claim 11, further comprising: Based on the resource set associated with the SCell, performing a random access channel (RACH) procedure in response to the PDCCH command, wherein the performing the RACH procedure includes sending a first message via each beam in a beam set, the first message including a RACH preamble indicated in the PDCCH command; In response to the first message, receiving a second message from the base station via a PDCCH associated with the SCell, the second message including a cell-radio network temporary identifier (C-RNTI), wherein the C-RNTI corresponds to a beam in the beam set; and Based on the second message, an uplink beam corresponding to an uplink control channel associated with the SCell is determined.

13. A method of wireless communication at a base station, comprising: Based on detecting a beam failure of a secondary cell SCell at a user equipment UE, receiving a scheduling request SR from the UE via a primary cell PCell; Sending a first message from the PCell to the UE, the first message including one of an uplink UL grant or a trigger for UL reporting; receiving, at the PCell, from the UE, a second message including information indicating a beam failure of the SCell; and After sending a downlink indication that control channel resources corresponding to the SCell are activated for beam recovery, a physical downlink control channel (PDCCH) command is sent from the SCell.

14. The method according to claim 13, wherein: The second message further identifies a preferred candidate beam associated with the SCell, and the method further includes: A control resource set CORESET transmission configuration indicator TCI state activation signal for the preferred candidate beam associated with the SCell is sent from the PCell.

15. The method according to claim 14, wherein: The CORESET TCI state activation signal indicates that resources for a control channel associated with the preferred candidate beam have been activated by the base station.

16. The method according to claim 13, further comprising: A control resource set CORESET transmission configuration indicator TCI state activation signal is sent from the PCell, where the signal indicates activation of a resource set associated with the SCell.

17. The method according to claim 16, further comprising: Sending a physical downlink control channel (PDCCH) command via a downlink control channel associated with the SCell; and In response to the PDCCH command, a random access channel (RACH) message is received via the SCell, wherein an uplink beam associated with the SCell is determined by the UE based on a RACH procedure with the SCell.

18. The method according to claim 17, wherein: The RACH process is performed based on the resource set associated with the SCell, and the method further includes: A confirmation message is sent to the UE, wherein the uplink beam associated with the SCell is determined by the UE based on the confirmation message from the base station.

19. A method of wireless communication at a base station, comprising: receiving a scheduling request SR from a user equipment UE via a primary cell PCell, where the SR includes information indicating a beam failure of a secondary cell SCell; and In response to the SR, a physical downlink control channel (PDCCH) command is sent from the PCell, the PDCCH command indicating a resource set associated with the SCell, The physical downlink control channel command includes a request for an L1-RSRP report of the SCell downlink beam and / or a request for reporting a beam ID corresponding to a preferred downlink beam determined by the UE.

20. The method according to claim 19, wherein: The PDCCH command enables the UE to determine a downlink beam corresponding to a downlink control channel associated with the SCell based on the PDCCH command.

21. The method of claim 19, further comprising: Based on the resource set associated with the SCell, receiving a first message from the UE at the SCell via each of the beam sets in response to the PDCCH command, the first message including a random access channel RACH preamble indicated in the PDCCH command; and In response to the first message, a second message is sent via the PDCCH associated with the SCell, the second message including a cell-radio network temporary identifier C-RNTI, wherein the C-RNTI corresponds to a beam in the beam set, wherein the UE determines an uplink beam corresponding to an uplink control channel associated with the SCell based on the second message.

22. An apparatus for wireless communication, the apparatus comprising: Memory; as well as at least one processor coupled to the memory and configured to: Detecting SCell beam failure in the secondary cell; In response to detecting the SCell beam failure, sending a scheduling request SR to the base station via the primary cell PCell; receiving a first message from the base station via the PCell, the first message including one of an uplink (UL) grant or a trigger for UL reporting; Sending a second message to the base station via the PCell and based on the trigger, the second message including information indicating a beam failure of the SCell; and After receiving a downlink indication that control channel resources corresponding to the SCell are activated for beam recovery, a physical downlink control channel (PDCCH) order is received from the base station via the SCell.

23. The device according to claim 22, wherein: The second message further identifies a preferred candidate beam associated with the SCell, and wherein the at least one processor is further configured to: receiving a control resource set CORESET transmission configuration indicator TCI state activation signal for the preferred candidate beam associated with the SCell from the base station via the PCell; and Based on the CORESET TCI state activation signal, a control channel associated with the preferred candidate beam for communicating with the base station is determined.

24. The device according to claim 22, wherein: The at least one processor is further configured to: receiving a control resource set CORESET transmission configuration indicator TCI state activation signal from the base station via the PCell, the signal indicating activation of a resource set associated with the SCell; and Based on the resource set associated with the SCell, a downlink beam associated with the SCell is determined.

25. The device according to claim 24, wherein: The at least one processor is further configured to: Receiving a physical downlink control channel (PDCCH) command via a downlink control channel associated with the SCell; In response to the PDCCH command, performing a random access channel RACH process; and Based on the RACH process, an uplink beam associated with the SCell is determined.

26. An apparatus for wireless communication, the apparatus comprising: Memory; as well as at least one processor coupled to the memory and configured to: Detecting SCell beam failure in the secondary cell; Sending a scheduling request SR to a base station via a primary cell PCell, where the SR includes information indicating a beam failure of the SCell; and In response to the SR, receiving a physical downlink control channel (PDCCH) order from the base station via the PCell indicating a resource set associated with the SCell, The physical downlink control channel command includes a request for an L1-RSRP report of an SCell downlink beam and / or a request for reporting a beam ID corresponding to a preferred downlink beam determined by the apparatus for wireless communication.

27. The device according to claim 26, wherein The at least one processor is further configured to: Based on the resource set associated with the SCell, performing a random access channel (RACH) procedure in response to the PDCCH command, wherein the performing the RACH procedure includes sending a first message via each beam in a beam set, the first message including a RACH preamble indicated in the PDCCH command; In response to the first message, receiving a second message from the base station via a PDCCH associated with the SCell, the second message including a cell-radio network temporary identifier (C-RNTI), wherein the C-RNTI corresponds to a beam in the beam set; and Based on the second message, an uplink beam corresponding to an uplink control channel associated with the SCell is determined.

28. The device according to claim 26, wherein The at least one processor is further configured to: Based on the PDCCH command, a downlink beam corresponding to a downlink control channel associated with the SCell is determined.

29. An apparatus for wireless communication, the apparatus comprising: Memory; as well as at least one processor coupled to the memory and configured to: Based on detecting a beam failure of a secondary cell SCell at a user equipment UE, receiving a scheduling request SR from the UE via a primary cell PCell; Sending a first message from the PCell to the UE, the first message including one of an uplink UL grant or a trigger for UL reporting; receiving, at the PCell, from the UE, a second message including information indicating a beam failure of the SCell; and After sending a downlink indication that control channel resources corresponding to the SCell are activated for beam recovery, a physical downlink control channel (PDCCH) command is sent from the SCell.

30. The device according to claim 29, wherein: The second message further identifies a preferred candidate beam associated with the SCell, and wherein the at least one processor is further configured to: A control resource set CORESET transmission configuration indicator TCI state activation signal for the preferred candidate beam associated with the SCell is sent from the PCell.

31. The device according to claim 29, wherein: The at least one processor is further configured to: A control resource set CORESET transmission configuration indicator TCI state activation signal is sent from the PCell, where the signal indicates activation of a resource set associated with the SCell.

32. The device according to claim 31, wherein The at least one processor is further configured to: sending a physical downlink control channel (PDCCH) command via a downlink control channel associated with the SCell; and In response to the PDCCH command, a random access channel (RACH) message is received via the SCell, wherein an uplink beam associated with the SCell is determined by the UE based on a RACH procedure with the SCell.

33. The device according to claim 32, wherein: Based on the resource set associated with the SCell, the RACH procedure is performed, and wherein the at least one processor is further configured to: A confirmation message is sent to the UE, wherein the uplink beam associated with the SCell is determined by the UE based on the confirmation message from the base station.

34. An apparatus for wireless communication, the apparatus comprising: Memory; as well as at least one processor coupled to the memory and configured to: receiving a scheduling request SR from a user equipment UE via a primary cell PCell, the SR including information indicating a beam failure of a secondary cell SCell; and In response to the SR, a physical downlink control channel (PDCCH) command is sent from the PCell, the PDCCH command indicating a resource set associated with the SCell, The physical downlink control channel command includes a request for an L1-RSRP report of the SCell downlink beam and / or a request for reporting a beam ID corresponding to a preferred downlink beam determined by the UE.

35. The device according to claim 34, wherein The at least one processor is further configured to: receiving, based on the set of resources associated with the SCell, a first message from the UE at the SCell via each of the beam sets in response to the PDCCH order, the first message including a RACH preamble indicated in the PDCCH order; and In response to the first message, a second message is sent via the PDCCH associated with the SCell, the second message including a cell-radio network temporary identifier C-RNTI, wherein the C-RNTI corresponds to a beam in the beam set, wherein the UE determines an uplink beam corresponding to an uplink control channel associated with the SCell based on the second message.

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