Patent Publication Number: US-2023156845-A1

Title: Beam failure recovery for a multi-transmission/reception point in a primary cell

Description:
CROSS REFERENCE 
     The present application is a 371 national stage filing of International PCT Application No. PCT/CN2020/092325 by KHOSHNEVISAN et al. entitled “BEAM FAILURE RECOVERY FOR A MULTI-TRANSMISSION/RECEPTION POINT IN A PRIMARY CELL,” filed May 26, 2020, which is assigned to the assignee hereof, and which is expressly incorporated by reference in its entirety herein. 
    
    
     FIELD OF TECHNOLOGY 
     The following relates generally to wireless communications and more specifically to beam failure recovery for a multi-transmission/reception point in a primary cell. 
     BACKGROUND 
     Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple-access communications system may include one or more base stations or one or more network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE). 
     In some wireless communication systems, a UE and a base station may communicate over a communication link using a directional beam. Changes in the radio environment between the UE and the base station may degrade the quality of the beam used by the UE and the base station, which may result in communication failures between the UE and the base station. The UE may attempt to perform a beam failure recovery (BFR) procedure to re-establish connection with the base station. Additionally, in some wireless communication systems a UE may be in communication with more than one transmission-reception point (TRP) (e.g., in a multi-TRP configuration). Each of the more than one TRP may transmit downlink transmissions to the UE according to a beam configuration and the UE may decode the downlink transmissions from each of the more than one TRPs according to the beam configurations. Efficient BFR procedures in multi-TRP configurations may help enhance multi-TRP communications. 
     SUMMARY 
     The described techniques relate to improved methods, systems, devices, and apparatuses that support beam failure recovery (BFR) for a multi-transmission/reception point (TRP) in a primary cell (PCell), which may be an example of a PCell and/or a primary/secondary cell (P/SCell). Generally, the described techniques provide for per-TRP BFR procedures at a PCell that is configured with a component carrier (CC) associated with two control resource set (CORESET) pool index values (CORESETPoolIndex). Different CORESET pool index values are configured for a user equipment (UE), each of which being associated with correspondingly different TRPs of the PCell. The PCell (e.g., base station) may configure the UE with an indication of a set of candidate beams available for the BFR procedure, with the set of candidate beams including a first subset of candidate beams for a first CORESET pool index value/TRP and a second subset of candidate beams for a second CORESET pool index value/TRP. The UE may identify or otherwise detect a beam failure on the CC on a currently active beam of the PCell and select a new candidate beam from the set of candidate beams. For example, the UE may detect the beam failure based on a reference signal (e.g., a beam failure detection (BFD) reference signal) from a TRP failing to satisfy a threshold performance metric. The reference signal may be associated with the first CORESET pool index value or the second CORESET pool index value. Accordingly, the UE may know that the beam failure is associated with the corresponding first TRP or second TRP and select a new candidate beam from the respective first or second subset of candidate beams, respectively. For example, the UE may measure candidate beams in the associated subset of candidate beams to identify the best performing candidate beam. The UE may select the best performing candidate beam (or N best performing candidate beams) as the new candidate beam. The UE may transmit an access message (e.g., such as a random access channel (RACH) message, a link recovery request (LRR), and the like) that indicates the new candidate beam. The BFR procedure may establish the new candidate beam as the new active beam with the corresponding TRP. 
     A method for wireless communication at a UE is described. The method may include receiving a configuration for a carrier associated with a PCell, the carrier configured with a first CORESET pool index value and a second CORESET pool index value; receiving an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams comprising a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value; detecting a beam failure on the carrier on an active beam of the PCell that is associated with the first CORESET pool index value or the second CORESET pool index value; selecting a new candidate beam from the set of candidate beams based at least in part on monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam; and transmitting an access message indicating the new candidate beam during the BFR procedure. 
     An apparatus for wireless communication at a UE is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the processor to receive a configuration for a carrier associated with a PCell, the carrier configured with a first CORESET pool index value and a second CORESET pool index value; receive an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams comprising a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value; detect a beam failure on the carrier on an active beam of the PCell that is associated with the first CORESET pool index value or the second CORESET pool index value; select a new candidate beam from the set of candidate beams based at least in part on monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam; and transmit an access message indicating the new candidate beam during the BFR procedure. 
     Another apparatus for wireless communication at a UE is described. The apparatus may include means for receiving a configuration for a carrier associated with a PCell, the carrier configured with a first CORESET pool index value and a second CORESET pool index value; receiving an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams comprising a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value; detecting a beam failure on the carrier on an active beam of the PCell that is associated with the first CORESET pool index value or the second CORESET pool index value; selecting a new candidate beam from the set of candidate beams based at least in part on monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam; and transmitting an access message indicating the new candidate beam during the BFR procedure. 
     A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to receive a configuration for a carrier associated with a PCell, the carrier configured with a first CORESET pool index value and a second CORESET pool index value; receive an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams comprising a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value; detect a beam failure on the carrier on an active beam of the PCell that is associated with the first CORESET pool index value or the second CORESET pool index value; select a new candidate beam from the set of candidate beams based at least in part on monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam; and transmit an access message indicating the new candidate beam during the BFR procedure. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for identifying a first subset of random access resources associated with a first subset of candidate beam detection resources corresponding to the first subset of candidate beams and a second subset of random access resources associated with a second subset of candidate beam detection resources corresponding to the second subset of candidate beams, wherein the access message is transmitted based at least in part on the first set of random access resources or the second set of random access resources. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving an indication of a first set of random access resources associated with the first CORESET pool index value and a second set of random access resources associated with the second CORESET pool index value. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the new candidate beam is associated with the first subset of candidate beams; and selecting a random access resource from the first set of random access resources that corresponds to the new candidate beam to transmit the access message. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for configuring, based at least in part on the detected beam failure, the access message to indicate the first CORESET pool index value or the second CORESET pool index. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for configuring, based at least in part on the detected beam failure, the access message to indicate the beam failure was detected on the PCell; and transmitting the access message using a first set of random access resources associated with the first CORESET pool index value or a second set of random access resources associated with the second CORESET pool index value. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for monitoring for an access response message on a first recovery search space configured with a first CORESET that is associated with the first CORESET pool index value or on a second recovery search space configured with a second CORESET that is associated with the second CORESET pool index value. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the new candidate beam is associated with the first subset of candidate beams; and monitoring for the access response message on the first recovery search space. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a control channel signal in the first recovery search space; and determining that the BFR procedure is complete based at least in part on receiving the control channel signal in the first recovery search space. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for monitoring for an access response message on a first recovery search space associated with the first CORESET pool index value or on a second recovery search space associated with the second CORESET pool index value, the first recovery search space and the second recovery search space associated with a common CORESET. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the new candidate beam is associated with the first subset of candidate beams; and monitoring for the access response message in the first recovery search space. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a control channel signal in the first recovery search space; and determining that the BFR procedure is complete based at least in part on receiving the control channel signal in the first recovery search space. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the new candidate beam is associated with the first CORESET pool index value or the second CORESET pool index value; and updating, based at least in part on the determining, a CORESET pool index value of the common CORESET. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, updating the CORESET pool index value may include operations, features, means, or instructions for updating the CORESET pool index value of the common CORESET to correspond to the new candidate beam CORESET pool index value. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the new candidate beam is associated with the first CORESET pool index value; and updating, based at least in part on the determining, a quasi-location relationship for a CORESET with index 0, wherein the updated quasi-colocation relationship corresponds to a quasi-colocation configuration of the new candidate beam. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the new candidate beam is associated with the first CORESET pool index value or the second CORESET pool index value; and updating, based at least in part on the determining, a quasi-location relationship for each control resource associated with the first CORESET pool index value or the second CORESET pool index value, wherein the updated quasi-colocation relationship corresponds to a quasi-colocation configuration of the new candidate beam. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for updating an activated set of transmission configuration indicator states for a data channel to a transmission configuration indicator state of the new candidate beam. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first CORESET pool index value is associated with a physical cell identifier associated with the PCell and the second CORESET pool index value is associated with a radio resource control configured physical cell identifier. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the resource comprises a first set of candidate beam detection resources associated with the physical cell identifier and a second set of candidate beam detection resources associated with the radio resource control configured physical cell identifier. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the new candidate beam is associated with a synchronization signal block comprising an index of a second set of synchronization signal blocks. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for identifying a first set of random access resources associated with the physical cell identifier and a second set of random access resources associated with the radio resource control configured physical cell identifier, wherein the access message is transmitted on the first set of random access resources or the second set of random access resources. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the beam failure on the active beam of the PCell is associated with the first CORESET pool index value, wherein the BFR procedure comprises a PCell BFR procedure. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the beam failure on the active beam of the PCell is associated with the second CORESET pool index value, wherein the BFR procedure comprises a secondary cell BFR procedure. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the secondary cell BFR procedure may include operations, features, means, or instructions for transmitting a link recovery request message in an uplink control channel; receiving, based at least in part on the link recovery request message, a grant scheduling an uplink transmission for the UE; and transmitting the uplink transmission that comprises a medium access control (MAC) control element (CE) indicating the second CORESET pool index value of the PCell. 
     A method for wireless communication at a base station is described. The method may include transmitting, to a UE, a configuration for a carrier associated with a PCell associated with the base station, the carrier configured with a first CORESET pool index value and a second CORESET pool index value; transmitting an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams comprising a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value; and receiving, based at least in part on the UE detecting a beam failure on the carrier on an active beam of the PCell associated with the first CORESET pool index value or the second CORESET pool index value, an access message indicating a new candidate beam, the new candidate beam selected from the set of candidate beams based at least in part on the UE monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam. 
     An apparatus for wireless communication at a base station is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the processor to transmit, to a UE, a configuration for a carrier associated with a PCell associated with the base station, the carrier configured with a first CORESET pool index value and a second CORESET pool index value; transmit an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams comprising a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value; and receive, based at least in part on the UE detecting a beam failure on the carrier on an active beam of the PCell associated with the first CORESET pool index value or the second CORESET pool index value, an access message indicating a new candidate beam, the new candidate beam selected from the set of candidate beams based at least in part on the UE monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam. 
     Another apparatus for wireless communication at a base station is described. The apparatus may include means for transmitting, to a UE, a configuration for a carrier associated with a PCell associated with the base station, the carrier configured with a first CORESET pool index value and a second CORESET pool index value; transmitting an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams comprising a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value; and receiving, based at least in part on the UE detecting a beam failure on the carrier on an active beam of the PCell associated with the first CORESET pool index value or the second CORESET pool index value, an access message indicating a new candidate beam, the new candidate beam selected from the set of candidate beams based at least in part on the UE monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam. 
     A non-transitory computer-readable medium storing code for wireless communication at a base station is described. The code may include instructions executable by a processor to transmit, to a UE, a configuration for a carrier associated with a PCell associated with the base station, the carrier configured with a first CORESET pool index value and a second CORESET pool index value; transmit an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams comprising a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value; and receive, based at least in part on the UE detecting a beam failure on the carrier on an active beam of the PCell associated with the first CORESET pool index value or the second CORESET pool index value, an access message indicating a new candidate beam, the new candidate beam selected from the set of candidate beams based at least in part on the UE monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for identifying a first subset of random access resources associated with a first set of candidate beam detection resources corresponding to the first subset of candidate beams and a second subset of random access resources associated with the second set of candidate beam detection resources corresponding to the second subset of candidate beams, wherein the access message is received based at least in part on the first set of random access resources or the second set of random access resources. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the new candidate beam is associated with the first subset of candidate beams, wherein the access message is received on a random access resource selected from the first set of random access resources that corresponds to the new candidate beam. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting an indication of a first set of random access resources associated with the first CORESET pool index value and a second set of random access resources associated with the second CORESET pool index value. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the new candidate beam is associated with the first subset of candidate beams, wherein the access message is received on a random access resource selected from the first set of random access resources that corresponds to the new candidate beam. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the access message indicates the first CORESET pool index value or the second CORESET pool index. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving the access message using a first set of random access resources associated with the first CORESET pool index value or a second set of random access resources associated with the second CORESET pool index value, wherein the access message indicates the beam failure was detected on the PCell. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting an access response message on a first recovery search space configured with a first CORESET that is associated with the first CORESET pool index value or on a second recovery search space configured with a second CORESET that is associated with the second CORESET pool index value. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the new candidate beam is associated with the first subset of candidate beams; and transmitting the access response message on the first recovery search space. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting a control channel signal in the first recovery search space, wherein the BFR procedure is complete based at least in part on transmitting the control channel signal in the first recovery search space. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting an access response message on a first recovery search space associated with the first CORESET pool index value or on a second recovery search space associated with the second CORESET pool index value, the first recovery search space and the second recovery search space associated with a common CORESET. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the new candidate beam is associated with the first subset of candidate beams, wherein the access response message is transmitted in the first recovery search space. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting a control channel signal in the first recovery search space, wherein the BFR procedure is complete based at least in part on transmitting the control channel signal in the first recovery search space. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the new candidate beam is associated with the first CORESET pool index value or the second CORESET pool index value may include updating, based at least in part on the access message, a CORESET pool index value of the common CORESET. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, updating the CORESET pool index value may include may include operations, features, means, or instructions for updating the CORESET pool index value of the common CORESET to correspond to the new candidate beam CORESET pool index value. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the new candidate beam is associated with the first CORESET pool index value, may include operations, features, means, or instructions for updating, based at least in part on the access message, a quasi-location relationship for a CORESET with index 0, wherein the updated quasi-colocation relationship corresponds to a quasi-colocation configuration of the new candidate beam. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the new candidate beam is associated with the first CORESET pool index value or the second CORESET pool index value, may include operations, features, means, or instructions for updating, based at least in part on the access message, a quasi-location relationship for each control resource associated with the first CORESET pool index value or the second CORESET pool index value, wherein the updated quasi-colocation relationship corresponds to a quasi-colocation configuration of the new candidate beam. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for updating an activated set of transmission configuration indicator states for a data channel to a transmission configuration indicator state of the new candidate beam. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first CORESET pool index value is associated with a physical cell identifier associated with the PCell and the second CORESET pool index value is associated with a radio resource control configured physical cell identifier. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the resource comprises a first set of candidate beam detection resources associated with the physical cell identifier and a second set of candidate beam detection resources associated with the radio resource control configured physical cell identifier. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the new candidate beam is associated with a synchronization signal block comprising an index of a second set of synchronization signal blocks. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for configuring, for the UE, a first set of random access resources associated with the physical cell identifier and a second set of random access resources associated with the radio resource control configured physical cell identifier, wherein the access message is received on the first set of random access resources or the second set of random access resources. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the beam failure on the active beam of the PCell is associated with the first CORESET pool index value, wherein the BFR procedure comprises a PCell BFR procedure. 
     Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the beam failure on the active beam of the PCell is associated with the second CORESET pool index value, wherein the BFR procedure comprises a secondary cell BFR procedure. 
     In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the secondary cell BFR procedure may include operations, features, means, or instructions for receiving a link recovery request message in an uplink control channel; transmitting, based at least in part on the link recovery request message, a grant scheduling an uplink transmission for the UE; and receiving the uplink transmission that comprises a MAC CE indicating the second CORESET pool index value of the PCell. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates an example of a system for wireless communications that supports beam failure (BFR) recovery for a multi-transmission/reception point (TRP) in a primary cell (PCell) in accordance with aspects of the present disclosure. 
         FIG.  2    illustrates an example of a wireless communication system that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. 
         FIG.  3    illustrates an example of a process that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. 
         FIG.  4    illustrates an example of a process that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. 
         FIGS.  5  and  6    show block diagrams of devices that support BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. 
         FIG.  7    shows a block diagram of a communications manager that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. 
         FIG.  8    shows a diagram of a system including a device that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. 
         FIGS.  9  and  10    show block diagrams of devices that support BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. 
         FIG.  11    shows a block diagram of a communications manager that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. 
         FIG.  12    shows a diagram of a system including a device that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. 
         FIGS.  13  through  17    show flowcharts illustrating methods that support BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Wireless communication systems may operate in millimeter wave (mmW) frequency ranges, e.g., 28 GHz, 40 GHz, 60 GHz, etc. Wireless communications at these frequencies may be associated with increased signal attenuation (e.g., path loss), which may be influenced by various factors, such as temperature, barometric pressure, diffraction, etc. As a result, signal processing techniques, such as beamforming, may be used to coherently combine energy and overcome the path losses at these frequencies. Due to the increased amount of path loss in mmW communication systems, transmissions from the base station and/or the user equipment (UE) may be beamformed. Moreover, a receiving device may use beamforming techniques to configure antenna(s) and/or antenna array(s) such that transmissions are received in a directional manner. 
     Such beamforming techniques may be implemented in a multi-cell scenario where a primary cell (PCell), which may also include a primary/secondary cell (P/SCell), is associated with multiple transmission/reception points (TRPs). The PCell may configure a carrier for a UE that is associated with the TRPs, which transmit beamformed transmissions to the UE over the carrier. However, channel conditions may change (e.g., due to interference, UE mobility, etc.) such that the UE may experience a beam failure on the carrier. In some wireless communication systems, the UE would wait for the carrier to fail on each TRP before initiating a beam failure recovery (BFR) procedure to identify a new active beam to use for communications. However, this approach is inefficient and may result in a complete loss of communications between the UE and PCell. That is, it is inefficient for the UE to wait until the beam fails on each TRP before declaring a BFR for the carrier. Moreover, if the beam fails on each TRP, this may result in a complete link failure between the UE and PCell. 
     Aspects of the disclosure are initially described in the context of wireless communication systems. The described techniques relate to improved methods, systems, devices, and apparatuses that support beam failure recovery (BFR) for a multi-transmission/reception point (TRP) in a primary cell (PCell), which may be an example of a PCell and/or a primary/secondary cell (P/SCell). Generally, the described techniques provide for per-TRP BFR procedures at a PCell that is configured with a component carrier (CC) associated with two control resource set (CORESET) pool index values (CORESETPoolIndex). Different CORESET pool index values are configured for a user equipment (UE), each of which being associated with correspondingly different TRPs of the PCell. The PCell (e.g., base station) may configure the UE with an indication of a set of candidate beams available for the BFR procedure, with the set of candidate beams including a first subset of candidate beams for a first CORESET pool index value/TRP and a second subset of candidate beams for a second CORESET pool index value/TRP. The UE may identify or otherwise detect a beam failure on the CC on a currently active beam of the PCell and select a new candidate beam from the set of candidate beams. For example, the UE may detect the beam failure based on a reference signal (e.g., a beam failure detection (BFD) reference signal) from a TRP failing to satisfy a threshold performance metric. The reference signal may be associated with the first CORESET pool index value or the second CORESET pool index value. Accordingly, the UE may know that the beam failure is associated with the corresponding first TRP or second TRP and select a new candidate beam from the respective first or second subset of candidate beams, respectively. For example, the UE may measure candidate beams in the associated subset of candidate beams to identify the best performing candidate beam. The UE may select the best performing candidate beam (or N best performing candidate beams) as the new candidate beam. The UE may transmit an access message (e.g., such as a random access channel (RACH) message, a link recovery request (LRR), and the like) that indicates the new candidate beam. The BFR procedure may establish the new candidate beam as the new active beam with the corresponding TRP. 
     Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to BFR for a multi-TRP in a PCell. 
       FIG.  1    illustrates an example of a wireless communication system  100  that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. The wireless communication system  100  may include one or more base stations  105 , one or more UEs  115 , and a core network  130 . In some examples, the wireless communication system  100  may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communication system  100  may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, communications with low-cost and low-complexity devices, or any combination thereof. 
     The base stations  105  may be dispersed throughout a geographic area to form the wireless communication system  100  and may be devices in different forms or having different capabilities. The base stations  105  and the UEs  115  may wirelessly communicate via one or more communication links  125 . Each base station  105  may provide a coverage area  110  over which the UEs  115  and the base station  105  may establish one or more communication links  125 . The coverage area  110  may be an example of a geographic area over which a base station  105  and a UE  115  may support the communication of signals according to one or more radio access technologies. 
     The UEs  115  may be dispersed throughout a coverage area  110  of the wireless communication system  100 , and each UE  115  may be stationary, or mobile, or both at different times. The UEs  115  may be devices in different forms or having different capabilities. Some example UEs  115  are illustrated in  FIG.  1   . The UEs  115  described herein may be able to communicate with various types of devices, such as other UEs  115 , the base stations  105 , or network equipment (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment), as shown in  FIG.  1   . 
     The base stations  105  may communicate with the core network  130 , or with one another, or both. For example, the base stations  105  may interface with the core network  130  through one or more backhaul links  120  (e.g., via an S1, N2, N3, or other interface). The base stations  105  may communicate with one another over the backhaul links  120  (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations  105 ), or indirectly (e.g., via core network  130 ), or both. In some examples, the backhaul links  120  may be or include one or more wireless links. 
     One or more of the base stations  105  described herein may include or may be referred to by a person having ordinary skill in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB or a giga-NodeB (either of which may be referred to as a gNB), a Home NodeB, a Home eNodeB, or other suitable terminology. 
     A UE  115  may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client, among other examples. A UE  115  may also include or may be referred to as a personal electronic device such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, a UE  115  may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communications (MTC) device, among other examples, which may be implemented in various objects such as appliances, or vehicles, meters, among other examples. 
     The UEs  115  described herein may be able to communicate with various types of devices, such as other UEs  115  that may sometimes act as relays as well as the base stations  105  and the network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown in  FIG.  1   . 
     The UEs  115  and the base stations  105  may wirelessly communicate with one another via one or more communication links  125  over one or more carriers. The term “carrier” may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication links  125 . For example, a carrier used for a communication link  125  may include a portion of a radio frequency spectrum band (e.g., a bandwidth part (BWP)) that is operated according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling that coordinates operation for the carrier, user data, or other signaling. The wireless communication system  100  may support communication with a UE  115  using carrier aggregation or multi-carrier operation. A UE  115  may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both frequency division duplexing (FDD) and time division duplexing (TDD) component carriers. 
     In some examples (e.g., in a carrier aggregation configuration), a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers. A carrier may be associated with a frequency channel (e.g., an evolved universal mobile telecommunication system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN)) and may be positioned according to a channel raster for discovery by the UEs  115 . A carrier may be operated in a standalone mode where initial acquisition and connection may be conducted by the UEs  115  via the carrier, or the carrier may be operated in a non-standalone mode where a connection is anchored using a different carrier (e.g., of the same or a different radio access technology). 
     The communication links  125  shown in the wireless communication system  100  may include uplink transmissions from a UE  115  to a base station  105 , or downlink transmissions from a base station  105  to a UE  115 . Carriers may carry downlink or uplink communications (e.g., in an FDD mode) or may be configured to carry downlink and uplink communications (e.g., in a TDD mode). 
     A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth may be referred to as a “system bandwidth” of the carrier or the wireless communication system  100 . For example, the carrier bandwidth may be one of a number of determined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz)). Devices of the wireless communication system  100  (e.g., the base stations  105 , the UEs  115 , or both) may have hardware configurations that support communications over a particular carrier bandwidth or may be configurable to support communications over one of a set of carrier bandwidths. In some examples, the wireless communication system  100  may include base stations  105  or UEs  115  that support simultaneous communications via carriers associated with multiple carrier bandwidths. In some examples, each served UE  115  may be configured for operating over portions (e.g., a sub-band, a BWP) or all of a carrier bandwidth. 
     Signal waveforms transmitted over a carrier may be made up of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both). Thus, the more resource elements that a UE  115  receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE  115 . A wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers or beams), and the use of multiple spatial layers may further increase the data rate or data integrity for communications with a UE  115 . 
     One or more numerologies for a carrier may be supported, where a numerology may include a subcarrier spacing (Δf) and a cyclic prefix. A carrier may be divided into one or more BWPs having the same or different numerologies. In some examples, a UE  115  may be configured with multiple BWPs. In some examples, a single BWP for a carrier may be active at a given time and communications for the UE  115  may be restricted to one or more active BWPs. 
     The time intervals for the base stations  105  or the UEs  115  may be expressed in multiples of a basic time unit which may, for example, refer to a sampling period of T s =1/(Δf max ·N f ) seconds, where Δf max  may represent the maximum supported subcarrier spacing, and N f  may represent the maximum supported discrete Fourier transform (DFT) size. Time intervals of a communications resource may be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023). 
     Each frame may include multiple consecutively numbered subframes or slots, and each subframe or slot may have the same duration. In some examples, a frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into a number of slots. Alternatively, each frame may include a variable number of slots, and the number of slots may depend on subcarrier spacing. Each slot may include a number of symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period). In some wireless communication systems  100 , a slot may further be divided into multiple mini-slots containing one or more symbols. Excluding the cyclic prefix, each symbol period may contain one or more (e.g., N f ) sampling periods. The duration of a symbol period may depend on the subcarrier spacing or frequency band of operation. 
     A subframe, a slot, a mini-slot, or a symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communication system  100  and may be referred to as a transmission time interval (TTI). In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system  100  may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs)). 
     Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using one or more of time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. A control region (e.g., a CORESET) for a physical control channel may be defined by a number of symbol periods and may extend across the system bandwidth or a subset of the system bandwidth of the carrier. One or more control regions (e.g., CORESETs) may be configured for a set of the UEs  115 . For example, one or more of the UEs  115  may monitor or search control regions for control information according to one or more search space sets, and each search space set may include one or multiple control channel candidates in one or more aggregation levels arranged in a cascaded manner. An aggregation level for a control channel candidate may refer to a number of control channel resources (e.g., control channel elements (CCEs)) associated with encoded information for a control information format having a given payload size. Search space sets may include common search space sets configured for sending control information to multiple UEs  115  and UE-specific search space sets for sending control information to a specific UE  115 . 
     Each base station  105  may provide communication coverage via one or more cells, for example a macro cell, a small cell, a hot spot, or other types of cells, or any combination thereof. The term “cell” may refer to a logical communication entity used for communication with a base station  105  (e.g., over a carrier) and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID), or others). In some examples, a cell may also refer to a geographic coverage area  110  or a portion of a geographic coverage area  110  (e.g., a sector) over which the logical communication entity operates. Such cells may range from smaller areas (e.g., a structure, a subset of structure) to larger areas depending on various factors such as the capabilities of the base station  105 . For example, a cell may be or include a building, a subset of a building, or exterior spaces between or overlapping with geographic coverage areas  110 , among other examples. 
     A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by the UEs  115  with service subscriptions with the network provider supporting the macro cell. A small cell may be associated with a lower-powered base station  105 , as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells may provide unrestricted access to the UEs  115  with service subscriptions with the network provider or may provide restricted access to the UEs  115  having an association with the small cell (e.g., the UEs  115  in a closed subscriber group (CSG), the UEs  115  associated with users in a home or office). A base station  105  may support one or multiple cells and may also support communications over the one or more cells using one or multiple component carriers. 
     In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB)) that may provide access for different types of devices. 
     In some examples, a base station  105  may be movable and therefore provide communication coverage for a moving geographic coverage area  110 . In some examples, different geographic coverage areas  110  associated with different technologies may overlap, but the different geographic coverage areas  110  may be supported by the same base station  105 . In other examples, the overlapping geographic coverage areas  110  associated with different technologies may be supported by different base stations  105 . The wireless communication system  100  may include, for example, a heterogeneous network in which different types of the base stations  105  provide coverage for various geographic coverage areas  110  using the same or different radio access technologies. 
     The wireless communication system  100  may support synchronous or asynchronous operation. For synchronous operation, the base stations  105  may have similar frame timings, and transmissions from different base stations  105  may be approximately aligned in time. For asynchronous operation, the base stations  105  may have different frame timings, and transmissions from different base stations  105  may, in some examples, not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operations. 
     Some UEs  115 , such as MTC or IoT devices, may be low cost or low complexity devices and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication). M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station  105  without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay such information to a central server or application program that makes use of the information or presents the information to humans interacting with the application program. Some UEs  115  may be designed to collect information or enable automated behavior of machines or other devices. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging. 
     Some UEs  115  may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (e.g., a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously). In some examples, half-duplex communications may be performed at a reduced peak rate. Other power conservation techniques for the UEs  115  include entering a power saving deep sleep mode when not engaging in active communications, operating over a limited bandwidth (e.g., according to narrowband communications), or a combination of these techniques. For example, some UEs  115  may be configured for operation using a narrowband protocol type that is associated with a defined portion or range (e.g., set of subcarriers or resource blocks (RBs)) within a carrier, within a guard-band of a carrier, or outside of a carrier. 
     The wireless communication system  100  may be configured to support ultra-reliable communications or low-latency communications, or various combinations thereof. For example, the wireless communication system  100  may be configured to support ultra-reliable low-latency communications (URLLC) or mission critical communications. The UEs  115  may be designed to support ultra-reliable, low-latency, or critical functions (e.g., mission critical functions). Ultra-reliable communications may include private communication or group communication and may be supported by one or more mission critical services such as mission critical push-to-talk (MCPTT), mission critical video (MCVideo), or mission critical data (MCData). Support for mission critical functions may include prioritization of services, and mission critical services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission critical, and ultra-reliable low-latency may be used interchangeably herein. 
     In some examples, a UE  115  may also be able to communicate directly with other UEs  115  over a device-to-device (D2D) communication link  135  (e.g., using a peer-to-peer (P2P) or D2D protocol). One or more UEs  115  utilizing D2D communications may be within the geographic coverage area  110  of a base station  105 . Other UEs  115  in such a group may be outside the geographic coverage area  110  of a base station  105  or be otherwise unable to receive transmissions from a base station  105 . In some examples, groups of the UEs  115  communicating via D2D communications may utilize a one-to-many (1:M) system in which each UE  115  transmits to every other UE  115  in the group. In some examples, a base station  105  facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between the UEs  115  without the involvement of a base station  105 . 
     In some systems, the D2D communication link  135  may be an example of a communication channel, such as a sidelink communication channel, between vehicles (e.g., UEs  115 ). In some examples, vehicles may communicate using vehicle-to-everything (V2X) communications, vehicle-to-vehicle (V2V) communications, or some combination of these. A vehicle may signal information related to traffic conditions, signal scheduling, weather, safety, emergencies, or any other information relevant to a V2X system. In some examples, vehicles in a V2X system may communicate with roadside infrastructure, such as roadside units, or with the network via one or more network nodes (e.g., base stations  105 ) using vehicle-to-network (V2N) communications, or with both. 
     The core network  130  may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network  130  may be an evolved packet core (EPC) or 5G core (5GC), which may include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) and at least one user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW), a Packet Data Network (PDN) gateway (P-GW), or a user plane function (UPF)). The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for the UEs  115  served by the base stations  105  associated with the core network  130 . User IP packets may be transferred through the user plane entity, which may provide IP address allocation as well as other functions. The user plane entity may be connected to the network operators IP services  150 . The operators IP services  150  may include access to the Internet, Intranet(s), an IP Multimedia Subsystem (IMS), or a Packet-Switched Streaming Service. 
     Some of the network devices, such as a base station  105 , may include subcomponents such as an access network entity  140 , which may be an example of an access node controller (ANC). Each access network entity  140  may communicate with the UEs  115  through one or more other access network transmission entities  145 , which may be referred to as radio heads, smart radio heads, or transmission/reception points (TRPs). Each access network transmission entity  145  may include one or more antenna panels. In some configurations, various functions of each access network entity  140  or base station  105  may be distributed across various network devices (e.g., radio heads and ANCs) or consolidated into a single network device (e.g., a base station  105 ). 
     The wireless communication system  100  may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range from approximately one decimeter to one meter in length. The UHF waves may be blocked or redirected by buildings and environmental features, but the waves may penetrate structures sufficiently for a macro cell to provide service to the UEs  115  located indoors. The transmission of UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz. 
     The wireless communication system  100  may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band, or in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz), also known as the millimeter band. In some examples, the wireless communication system  100  may support millimeter wave (mmW) communications between the UEs  115  and the base stations  105 , and EHF antennas of the respective devices may be smaller and more closely spaced than UHF antennas. In some examples, this may facilitate use of antenna arrays within a device. The propagation of EHF transmissions, however, may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. The techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body. 
     The wireless communication system  100  may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system  100  may employ License Assisted Access (LAA), LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in unlicensed radio frequency spectrum bands, devices such as the base stations  105  and the UEs  115  may employ carrier sensing for collision detection and avoidance. In some examples, operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA). Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples. 
     A base station  105  or a UE  115  may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of a base station  105  or a UE  115  may be located within one or more antenna arrays or antenna panels, which may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, antennas or antenna arrays associated with a base station  105  may be located in diverse geographic locations. A base station  105  may have an antenna array with a number of rows and columns of antenna ports that the base station  105  may use to support beamforming of communications with a UE  115 . Likewise, a UE  115  may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, an antenna panel may support radio frequency beamforming for a signal transmitted via an antenna port. 
     The base stations  105  or the UEs  115  may use MIMO communications to exploit multipath signal propagation and increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such techniques may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO), where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO), where multiple spatial layers are transmitted to multiple devices. 
     Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station  105 , a UE  115 ) to shape or steer an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that some signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference. The adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying amplitude offsets, phase offsets, or both to signals carried via the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation). 
     A base station  105  or a UE  115  may use beam sweeping techniques as part of beam forming operations. For example, a base station  105  may use multiple antennas or antenna arrays (e.g., antenna panels) to conduct beamforming operations for directional communications with a UE  115 . Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by a base station  105  multiple times in different directions. For example, the base station  105  may transmit a signal according to different beamforming weight sets associated with different directions of transmission. Transmissions in different beam directions may be used to identify (e.g., by a transmitting device, such as a base station  105 , or by a receiving device, such as a UE  115 ) a beam direction for later transmission or reception by the base station  105 . 
     Some signals, such as data signals associated with a particular receiving device, may be transmitted by a base station  105  in a single beam direction (e.g., a direction associated with the receiving device, such as a UE  115 ). In some examples, the beam direction associated with transmissions along a single beam direction may be determined based on a signal that was transmitted in one or more beam directions. For example, a UE  115  may receive one or more of the signals transmitted by the base station  105  in different directions and may report to the base station  105  an indication of the signal that the UE  115  received with a highest signal quality or an otherwise acceptable signal quality. 
     In some examples, transmissions by a device (e.g., by a base station  105  or a UE  115 ) may be performed using multiple beam directions, and the device may use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from a base station  105  to a UE  115 ). The UE  115  may report feedback that indicates precoding weights for one or more beam directions, and the feedback may correspond to a configured number of beams across a system bandwidth or one or more sub-bands. The base station  105  may transmit a reference signal (e.g., a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS)), which may be precoded or unprecoded. The UE  115  may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook). Although these techniques are described with reference to signals transmitted in one or more directions by a base station  105 , a UE  115  may employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by the UE  115 ) or for transmitting a signal in a single direction (e.g., for transmitting data to a receiving device). 
     A receiving device (e.g., a UE  115 ) may try multiple receive configurations (e.g., directional listening) when receiving various signals from the base station  105 , such as synchronization signals, reference signals, beam selection signals, or other control signals. For example, a receiving device may try multiple receive directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different receive beamforming weight sets (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of an antenna array, or by processing received signals according to different receive beamforming weight sets applied to signals received at multiple antenna elements of an antenna array, any of which may be referred to as “listening” according to different receive configurations or receive directions. In some examples, a receiving device may use a single receive configuration to receive along a single beam direction (e.g., when receiving a data signal). The single receive configuration may be aligned in a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have a highest signal strength, highest signal-to-noise ratio (SNR), or otherwise acceptable signal quality based on listening according to multiple beam directions). 
     The wireless communication system  100  may be a packet-based network that operates according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use error detection techniques, error correction techniques, or both to support retransmissions at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE  115  and a base station  105  or a core network  130  supporting radio bearers for user plane data. At the physical layer, transport channels may be mapped to physical channels. 
     The UEs  115  and the base stations  105  may support retransmissions of data to increase the likelihood that data is received successfully. Hybrid automatic repeat request (HARQ) feedback is one technique for increasing the likelihood that data is received correctly over a communication link  125 . HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., low signal-to-noise conditions). In some examples, a device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval. 
     A UE  115  may receive a configuration for a carrier associated with a PCell, the carrier configured with a first CORESET pool index value and a second CORESET pool index value. The UE  115  may receive an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams comprising a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value. The UE  115  may detect a beam failure on the carrier on an active beam of the PCell that is associated with the first CORESET pool index value or the second CORESET pool index value. The UE  115  may select a new candidate beam from the set of candidate beams based at least in part on monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam. The UE  115  may transmit an access message indicating the new candidate beam during the BFR procedure. 
     A base station  105  may (e.g., when configured or otherwise acting as a PCell) transmit, to a UE  115 , a configuration for a carrier associated with a PCell associated with the base station, the carrier configured with a first CORESET pool index value and a second CORESET pool index value. The base station  105  may transmit an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams comprising a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value. The base station  105  may receive, based at least in part on the UE  115  detecting a beam failure on the carrier on an active beam of the PCell associated with the first CORESET pool index value or the second CORESET pool index value, an access message indicating a new candidate beam, the new candidate beam selected from the set of candidate beams based at least in part on the UE monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam. 
       FIG.  2    illustrates an example of a wireless communication system  200  that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. In some examples, wireless communication system  200  may implement aspects of wireless communication system  100 . Wireless communication system  200  may include a UE  205 , PCell  210 , and a number of TRPs  215  associated with PCell  210 , which may be examples of the corresponding devices described herein. TRPs  215  may, in this example, provide a multi-TRP PCell in which a first beam  220 - a  of a first TRP  215 - a  and a second beam  220 - b  of a second TRP  215 - b  provide communications with the UE  205 . 
     In some cases, the multi-TRP transmissions may be configured based on multiple downlink control information (DCI) communications, in which a first DCI (e.g., transmitted in PDCCH 1  from first TRP  215 - a ) schedules a downlink shared channel transmission (e.g., PDSCH 1  transmitted from first TRP  215 - a  via first beam  220 - a ), and a second DCI (e.g., transmitted in PDCCH 2  from second TRP  215 - b ) schedules a second downlink shared channel transmission (e.g., PDSCH 2  transmitted from second TRP  215 - b  via second beam  220 - b ). TRP  215  differentiation at the UE  205 , in some cases, may be based on a value of a CORESET pool index (e.g., CORESETPoolIndex), where each CORESET (e.g., up to a maximum of five CORESETs) can be configured with a value of CORESET pool index. In some cases, the value of CORESET pool index can be zero (0) or one (1), which groups the CORESETs into two groups, which may correspond to the different TRPs  215 . Only some CCs may be configured with two values of CORESET pool index, while other CCs may not be configured with two values of CORESET pool index and thus BFD/BFR for on a per-TRP  215  basis may be provided for CCs that are configured with two values of CORESET pool index. 
     In some cases, the UE  205  may be configured to provide per-TRP  215  BFR, which enables separate BFD and separate CBD for the beams corresponding to a TRP  215  in a CC that is configured with two values of CORESET pool index. In the absence of per-TRP  215  BFR, BFD and BCD may not be triggered until all beams in that CC become weak. With per-TRP  215  BFR, when beams for a given TRP become weak, beam recovery procedures can be performed and a best beam corresponding to that TRP  215  can be identified without having to wait for the beams of the other TRP  215  to also become weak, and thus reliability and communications efficiency can be enhanced. In the non-limiting example illustrated in  FIG.  2   , PCell  210  may be configured with two values of CORESET pool index, with one value associated with the first TRP  215 - a  and a second value associated with second TRP  215 - b . In this case, each TRP  215  may transmit one or more BFD reference signals that may be monitored by the UE  205 . In this example, the UE  205  may determine that the first beam  220 - a  of the first CORESET pool index value (e.g., CORESETPoolIndex=0) has a channel metric (e.g., a reference signal received power RSRP)) that is below a threshold value (e.g., when radio link quality is worse than a threshold Q out  for all the reference signals in BFD resources that are associated with the first CORESET pool index value). 
     Accordingly, UE  205  may be configured for a carrier (e.g., an individual CC, bandwidth part (BWP), and the like) associated with PCell  210  that is configured with the first CORESET pool index value (e.g., CORESETPoolIndex=0) and a second CORESET pool index value (e.g., CORESETPoolIndex=1). The first CORESET pool index value may be associated with the first TRP  215 - a  of PCell  210  and the second CORESET pool index value may be associated with the second TRP  215 - b  of PCell  210 . Each TRP  215  may transmit one or more BFD reference signals that are associated with their respective value of CORESET pool index. This may include two sets of BFD reference signals (e.g., failureDetectionResources) being configured, with each set corresponding to a different value of CORESET pool index. In another example this may include each reference signal (e.g., each resource within failureDetectionResources) being configured with a CORESET pool index value. If the resource is not configured with a CORESET pool index value, it may be considered associated with CORESET pool index value 0 (e.g., the first CORESET pool index value). Additionally, a resource may be configured with both values of CORESET pool indices. When the reference signals (e.g., failureDetectionResources) are not configured, the reference signal sets indicated in the active transmission configuration indicator (TCI) states of CORESETS configured with CORESET pool index value=0/1 (e.g., either CORESET pool index value) may determine the first/second set of resources, respectively. BFD for a value of CORESET pool index may be declared when the radio link quality is worse than Q_out for all the reference signals and the BFD resources that are associated with that CORESET pool index value. 
     UE  205  may also receive or otherwise identify an indication of a set of candidate beams available for a BFR procedure. The set of candidate beams may include a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value. In one example, this may include two lists of candidate beams (e.g., candidateBeamRSList) being configured, each corresponding to a CORESET pool index value. That is, UE  205  may be separately configured with the first subset of candidate beams associated with the first CORESET pool index value and the second subset of candidate beams associated with the second CORESET pool index value. 
     In another example, each reference signal of candidateBeamRSList may be configured with a CORESET pool index value. If a reference signal is not configured with a CORESET pool index value, that resource may be assumed to be associated with CORESET pool index value 0. In some examples, a reference signal may be configured with both values of CORESET pool index (e.g., the resource may be considered for both TRPs  215 ). 
     UE  205  may detect or otherwise determine that a beam failure has occurred (e.g., the RSRP on the active beam is less than Q_out) on the carrier of the active beam (e.g., either the first beam  220 - a  or the second beam  220 - b ) of PCell  210 . UE  205  may, based on the detected beam failure, select a new candidate beam from the set of candidate beams based on monitoring a resource (e.g., CBD resources) associated with the first CORESET pool index value or the second CORESET pool index value. When BFD is declared for a value of CORESET pool index, a new candidate beam (e.g., q_new) may be identified from within the candidate reference signals associated with the same value of CORESET pool index. Accordingly, UE  205  may select a new candidate beam from the set of candidate beams based on monitoring a resource (e.g., CBD resource(s)) associated with the first CORESET pool index value when the first beam  220 - a  experiences beam failure or the second CORESET pool index value when the second beam  220 - b  experiences beam failure. UE  205  may transmit or otherwise convey an access message to PCell  210  (e.g., via the first TRP  215 - a  if the conditions on the carrier permit and/or via the second TRP  215 - b ) indicating the new candidate beam during the BFR procedure. 
     In some aspects, UE  205  may receive or otherwise identify a first subset of random access resources (e.g., RACH resources/random access preamble indices) associated with the first subset of candidate beam detection (e.g., CBD) resources corresponding to the first subset of candidate beams and a second subset of random access resources associated with a second subset of CBD resources corresponding to the second subset of candidate beams. That is, dedicated RACH resources for BFR may also be associated with the value of the CORESET pool index. In some examples this may include an implicit indication based on an association of a RACH resource/random access preamble index with a candidate beam reference signal (e.g., as each candidate beam reference signal is already associated with a value of a CORESET pool index). The network (e.g., PCell  210 ) may determine which TRP/CORESET pool index value has experienced a beam failure (and the corresponding new beam q_new) in the PCell  210  based on the resource/random access preamble index of the received RACH (e.g., based on the random access resource used for transmitting the access message). 
     In some examples this may include two lists of RACH resources/random access preamble indices being configured, with each list of RACH resource/random access preamble index being associated with one of the CORESET pool index values. For example, UE  205  may receive an indication of a first set of random access resources associated with the first CORESET pool index value and a second set of random access resources associated with the second CORESET pool index value. Accordingly, UE  205  may determine that the new candidate beam is associated with the first subset of candidate beams and select a random access resource from the first set of random access resources corresponding to the new candidate beam to transmit the access message. In another example, UE  205  may determine that the new candidate beam is associated with the second subset of candidate beams and select a random access resource from the second set of random access resources corresponding to the new candidate beam to transmit the access message. 
     UE  205  may transmit or otherwise convey the access message utilizing the corresponding RACH resources/random access preamble to carry or otherwise convey an indication of the CORESET pool index value associated with the beam failure. UE  205  may reset the active beam associated with the TRP  215  experiencing the beam failure. 
     In some aspects, this may include updating various quasi-colocation (QCL) relationships. For example, UE  205  may determine that the new candidate beam is associated with the first CORESET pool index value and, therefore, update the QCL relationship for a CORESET with index 0 (e.g., the CORESET that is used for common search space procedures). The updated QCL relationship may correspond to the QCL configuration of the new candidate beam. That is, when the new candidate beam (e.g., q_new) corresponds to CORESET pool index value 0, the QCL assumptions for CORESET 0 may be updated (e.g., after 28 symbols after the last symbol carrying PDCCH). Accordingly, the updated QCL configuration may occur after a threshold time period. The QCL assumption (e.g., QCL configuration) for CORESET 0 may not be updated when the new candidate beam (e.g., q_new) corresponds to CORESET pool index value 1 (e.g., the second CORESET pool index value). In some aspects, this may be based on CORESET 0 being typically associated with CORESET pool index value 0. 
     In some aspects, this may include UE  205  determining that the new candidate beam is associated with the first or second CORESET pool index values. Accordingly, UE  205  may update the QCL relationship for each CORESET associated with the first CORESET pool index value or second CORESET pool index value, respectively. Again, the updated QCL relationship may correspond to the QCL configuration of the new candidate beam. That is, when the new candidate beam (e.g., q_new) corresponds to either CORESET pool index value, the QCL assumption for all CORESETS associated with the same value of CORESET pool index may be reset to the new candidate beam (e.g., 28 symbols after the last symbol carrying PDCCH). The set of activated TCI states for a PDSCH that correspond to the same value of CORESET pool index may be reset to the new candidate beam. Accordingly, UE  205  may update the activated set of TCI states for a data channel to a TCI state of the new candidate beam. 
     In some aspects, this may include UE  205  determining that the new candidate beam is associated with the first or second CORESET pool index value. UE  205  may update the CORESET pool index value of a common CORESET accordingly. For example, UE  205  may update the CORESET pool index value of the common CORESET to correspond to the CORESET pool index value of the new candidate beam. That is, when the new candidate beam corresponds to the first or second CORESET pool index value and one CORESET (e.g., the common CORESET) is configured for BFR, the CORESET pool index value of the CORESET that is associated with recovery search space ID(s) (e.g., recoverySearchSpaceId(s)) may be reset to the CORESET pool index value that the new candidate beam corresponds to. 
     In some aspects, the first CORESET pool index value may be associated with the PCI of PCell  210  and the second CORESET pool index value may be associated with an RRC configured PCI. That is, CORESET pool index value 0 may be associated with the serving cell&#39;s PCI (e.g., the PCI determined based on the primary synchronization signal/secondary synchronization signal (PSS)/(SSS) and the initial access procedure) while CORESET pool index value 1 may be associated with a different PCI that is RRC configured for UE  205 . In some examples, a secondary synchronization signal block (SSB) set may be configured for UE  205  that is associated with the RRC configured PCI, e.g., the new candidate beam may be associated with an SSB having an index of a second set of SSBs. Accordingly, in some examples the resource used to transmit the access message may correspond to a first set of CBD resources associated with the PCI of PCell  210  and a second set of CBD resources associated with the RRC configured PCI. 
     That is, two lists of reference signals (e.g., BFD RSs) may be configured for candidate beam reference signals (that are associated with the two values of CORESET pool index) that correspond to the two PCIs. Accordingly, UE  205  may identify a first set of random access resources associated with the PCI of PCell  210  and a second set of random access resources associated with the RRC configured PCI. If the candidate beam reference signal (e.g., for CBD) is an SSB and is associated with the second CORESET pool index value (e.g., CORESETPoolIndex=1), the corresponding SSB index may refer to the index from the second set of SSBs that are RRC configured (e.g., and therefore corresponding to the RRC configured PCI). In some aspects, the candidate SSB may be RRC configured with a set of random access occasions when the candidate SSB belongs to the second set of SSBs. Those random access occasions may be different than the random access occasions configured in the remaining minimum system information (RMSI) for the serving cell&#39;s PCI (e.g., the PCI of PCell  210 ). In some aspects, separate RACH parameters may be configured corresponding to the two sets of candidate reference signals associated with the two CORESET pool index values/two PCIs. 
     In some aspects, UE  205  may treat the second CORESET pool index value (e.g., CORESETPoolIndex=1) as an SCell for the BFR procedure. That is, UE  205  may determine that the beam failure on the active beam of PCell  210  is associated with the first CORESET pool index value (e.g., CORESETPoolIndex=0 and is associated with the first TRP  215 - a ) and, therefore, perform a PCell BFR procedure. When BFD is detected for the first CORESET pool index value (e.g., CORESETPoolIndex=0), the procedures corresponding to a PCell BFR procedure may be followed (e.g., RACH transmission, PDCCH reception in a recovery search ID, etc., as is generally described with reference to process  300 ). However, UE  205  may determine that the beam failure on the active beam of PCell  210  is associated with the second CORESET pool index value (e.g., CORESETPoolIndex=1 and is associated with the second TRP  215 - b ) and, therefore, perform a SCell BFR procedure. If BFD is detected for the second CORESET pool index value (e.g., CORESETPoolIndex=1) for PCell  210 , the procedures corresponding to an SCell BFR procedure may be followed. For example, a link recovery request (LRR) message may be transmitted in a configured PUCCH resource, and a grant scheduling an uplink transmission for UE  205  may be received in response. In this situation, the MAC CE beam failure response may convey an indication of an additional Ci field and corresponding AC/candidate reference signal ID fields (e.g., when Ci=1) associated with the CORESET pool index value 1 in the PCell  210 . The AC field may correspond to the candidate reference signal ID field. An example SCell BFR procedure, as may be modified according to the described techniques is generally described with reference to process  400 ). 
     Additional examples of beam failure declaration, candidate beam detection, beam recovery, and the like, are discussed with reference to process  300  of  FIG.  3    that generally illustrates a PCell BFR procedure and process  400  of  FIG.  4    that generally illustrates an SCell BFR procedure. 
       FIG.  3    illustrates an example of a process  300  that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. In some examples, process  300  may implement aspects of wireless communication systems  100  and/or  200 . Aspects of process  300  may be implemented by PCell  305  and/or UE  310 , which may be examples of corresponding devices described herein. In some aspects, PCell  305  may be associated with multiple TRPs. 
     Broadly, PCell  305  may configure UE  310  with a carrier that is configured with, or otherwise associated with, a first CORESET pool index value (e.g., CORESETPoolIndex=0) and a second CORESET pool index value (e.g., CORESETPoolIndex=1). PCell  305  may also configure UE  310  with the set of candidate beams available for a BFR procedure, the set of candidate beams including a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value. 
     At  315 , PCell  305  may transmit (and UE  310  may receive), a configuration for BFD reference signals (e.g., BFD-RS(s)). That is, BFD may be based on periodic CSI-RS resources configured by RRC (e.g., RRC parameter failureDetectionResoruces). Up to two single port reference signals may be configured. If not configured, the reference signal sets indicated by the active TCI states of CORESETs monitored by UE  310  may be used. For an active TCI state of a CORESET, there may be two reference signal indices, e.g., with QCL Type-D may be used. 
     At  320 , UE  310  may determine or otherwise declare a beam failure on an active beam of PCell  305  associated with the first CORESET pool index value or the second CORESET pool index value. In some aspects, the physical layer of UE  310  may assess the radio link quality according to the BFD set against a threshold (e.g., q_out). If the radio link quality is worse than q_out for all of the reference signals in the BFD resource set, the physical layer may provide an indication to higher layers (e.g., an indication that a beam failure has been detected). 
     At  325 , UE  310  may select a new candidate beam based on monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, e.g., perform CBD. In some aspects, CBD may be based on periodic CSI-RS/SSB configured by RRC (e.g., RRC parameter candidateBeamRSList). In some examples, up to 16 resources may be configured with the corresponding random access preamble index (e.g., for RACH). Upon request from higher layers, UE  310  may provide a reference signal index and RSRP among the lists that have equal or larger RSRP values than q_in (e.g., a configurable threshold). UE  305  may initiate RACH procedures (e.g., contention-free RACH procedures) based on the random access resource (e.g., random access preamble index) associated with a selected reference signal index with an RSRP value above the threshold (e.g., RS index q_new). Accordingly and at  330 , UE  310  may transmit (and PCell  305  may receive) a RACH message, e.g., the access message. 
     At  335 , PCell  305  may transmit (and UE  310  may receive) a BFR response. That is, UE  310  may monitor PDCCH in a search space set provided by a parameter recoverySearchSpaceID for detection of a DCI format that is CRC scramble by C-RNTI or MCS-C-RNTI starting from slot n+4. This may correspond to a random access response (e.g., BFR response in this case). If UE  310  receives the PDCCH within a window, the BFR procedure may be considered complete. In some aspects, the CORESET associated with the SSS provided by recoverySearchSpaceID may not be used for any other SSS. 
     Typically, various QCL assumptions may be adopted after RACH. For PDCCH monitoring and an SSS provided by recoverySearchSpaceID and for corresponding PDSCH receptions, UE  310  may assume the same QCL parameters as the ones associated with the reference signal index q_new (e.g., the QCL parameters of the new candidate beam) until UE  310  receives, e.g., by higher layers, an activation for a TCI state or any of the parameters TCI-StatesPDCCH-ToAddList and/or TCI-StatesPDCCH-ToReleaseList. After the 28th symbol from a last symbol of a first PDCCH reception and a SSS provided by recoverySearchSpaceID where UE  310  detects a DCI format with CRC scramble by C-RNTI or MCS-C-RNTI, UE  310  may assume the same QCL parameters as the ones associated with the reference signal index q_new for PDCCH monitoring in a CORESET with pool index value 0. 
     However, according to aspects of the described techniques ULE  310  may monitor for an access response message (e.g., the BFR response) on a first recovery search configured with a first CORESET that is associated with the first CORESET pool index value or on a second recovery search space configured with a second CORESET that is associated with the second CORESET pool index value. That is, two different CORESETS may be associated with two different recovery search spaces (e.g., two recoverySearchSpaceIDs can be configured). The two CORESETs may be configured with different CORESET pool index values. A recoverySearchSpaceID may be associated with a CORESET pool index value through the corresponding CORESET. Accordingly, UE  310  may determine that the new candidate beam is associated with the first subset of candidate beams and monitor for an access response message (e.g., the BFR response) on the first recovery search space. Similarly, UE  310  may determine that the new candidate beam is associated with the second subset of candidate beams and monitor for an access response message (e.g., the BFR response) on the second recovery search space. UE  310  may receive a control channel signal (e.g., PDCCH, which may include the access response message, or BFR response in this example) and the corresponding recovery search space and determine that the BFR procedure is complete based on receiving the control channel signal in the corresponding recovery search space. 
     In some aspects, only one CORESET may be used for BFR purposes. For example, UE  310  may monitor for the access response message (e.g., the BFR response) on a first recovery search associated with the first CORESET pool index value or on a second recovery search space associated with the second CORESET pool index value. In this example, the first and second recovery search spaces may be associated with a common CORESET (e.g., the single CORESET used for BFR purposes). In one aspect, this may include two recoverySearchSpaceIDs being configured, both associated with the same CORESET. The first recovery search space (e.g., the first recoverySearchSpaceId) may be associated with the first CORESET pool index value (e.g., CORESETPoolIndex=0) and the second recovery search space (e.g., the second recoverySearchSpaceID) may be associated with the second CORESET pool index value (e.g., CORESETPoolIndex=1). This association between the second recovery search space and the second CORESET pool index value may be a direct association (e.g., not through the CORESET). 
     If the RACH transmission at  330  in slot n is associated with a new candidate beam (e.g., q_new) that is associated with the value of CORESET pool index, UE  310  may monitor PDCCH in a search space set provided by recoverySearchSpaceID that is associated with the same value of CORESET pool index for detection of a DCI format with CRC scrambled by C-RNTI or MCS-C-RNTI starting from slot n+4. The BFR procedure for a CORESET pool index value may be completed when UE  310  receives PDCCH (e.g., the BFR response) in the corresponding recovery search space. PDCCH and corresponding PDSCH reception may use the same beam as q_new uses (e.g., the new candidate beam). 
     Accordingly, UE  310  may determine that the new candidate beam is associated with the first subset of candidate beams and monitor for an access response message (e.g., the BFR response) on the first recovery search space. Similarly, UE  310  may determine that the new candidate beam is associated with the second subset of candidate beams and monitor for an access response message (e.g., the BFR response) on the second recovery search space. UE  310  may receive a control channel signal (e.g., PDCCH, which may be an example of the access response message, or BFR response in this example) in the corresponding recovery search space and determine that the BFR procedure is complete based on receiving the control channel signal in the corresponding recovery search space. 
       FIG.  4    illustrates an example of a process  400  that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. In some examples, process  400  may implement aspects of wireless communication systems  100  and/or  200 , and/or process  300 . Aspects of process  400  may be implemented by PCell  405 , UE  410 , and/or SCell  415 , which may be examples of corresponding devices described herein. In some aspects, PCell  405  and/or SCell  415  may each be associated with multiple TRPs, respectively. Broadly, process  400  illustrates an example of an SCell BFR procedure that may be modified, at least in some aspects, according to the described techniques when a carrier on PCell  405  experiences beam failure. 
     Broadly, PCell  405  may configure UE  410  with a carrier that is configured with, or otherwise associated with, a first CORESET pool index value (e.g., CORESETPoolIndex=0) and a second CORESET pool index value (e.g., CORESETPoolIndex=1). PCell  405  may also configure UE  410  with the set of candidate beams available for a BFR procedure, the set of candidate beams including a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value. 
     As discussed above, aspects of the described techniques may include using a SCell BFR procedure when the beam failure on the active beam of PCell  405  is associated with the second CORESET pool index value (e.g., CORESETPoolIndex=1). Process  400  illustrates one non-limiting example of such a BFR procedure. 
     At  420 , SCell  415  may transmit (and UE  410  may receive) a configuration for BFD reference signals. That is, BFD may be based on periodic CSI-RS resources configured by RRC (e.g., RRC parameter failureDetectionResources). At  425 , UE  410  may determine or otherwise declare a beam failure on an active beam of SCell  415  associated with the first CORESET pool index value or the second CORESET pool index value. Although process  400  illustrates beam failure based on the reference signals and BFD based on SCell  415 , aspects of the described techniques may use the same process for BFD on PCell  405 . That is, although process  400  illustrates UE  410  detecting or otherwise declaring BFD on SCell  415 , it is to be understood that, in accordance with the described techniques, UE  410  may similarly detect or otherwise declare BFD on a carrier of PCell  405 . 
     At  430 , UE  410  may transmit (and PCell  405  may receive) a LRR message. The LRR message may be transmitted on PCell  405  (e.g., PUCCH-PCell and/or PUCCH-SCell) in which the PUCCH BFR is configured. The LRR message may be similar to a scheduling request (SR) and use PUCCH format 0 or 1. The LRR message may be transmitted in an uplink control channel. 
     At  435 , PCell  405  may transmit (and UE  410  may receive) an uplink grant. The uplink grant may include or use C-RNTI/MCS-C-RNTI and may serve as a response message to the LRR message. The uplink grant may schedule a PUSCH for UE  410  in which a BFR MAC CE may be transmitted. If UE  410  already has an uplink grant configured, the LRR message at  430  and the uplink grant  435  may be skipped. 
     At  440 , UE  410  may perform CBD. That is, before sending the BFR response indicating the MAC CE, UE  410  may identify the best new beam (e.g., select a new candidate beam) for the failed SCell  415  (or PCell  405  in this example). CBD may be similar to the description provided in process  300 . Up to 64 resources (e.g., candidateBeamRSSCellList, or candidateBeamRSPCellList in this example) may be configured in the set of candidate beams and they may be transmitted on the failed SCell  415  (or PCell  405  in this example) or on another CC in the same band. In some aspects, the BFR procedure illustrated in process  400  may not include a RACH process and, therefore, CBD resources may not be associated with a RACH resource. 
     At  445 , UE  410  may transmit (and PCell  405  may receive) a BFR MAC CE. In some aspects, the BFR MAC CE may carry or otherwise convey an indication of which cell the beam failure has occurred (e.g., a SCell index, or a PCell index in this example) and/or identify potential new candidate beams. For example, the BFR MAC CE may include a first row of C i  indications (e.g., up to eight C i  indications), with each C i  indication set to 1 to indicate that BFD has occurred in that CC. For each C i  indication set to 1, a subsequent row in the MAC CE may include an AC field set to 1 indicating that the candidate reference signal ID field is present. The remaining bits in the row may carry the candidate reference signal ID. The BFR MAC CE may be transmitted to PCell  405  and/or SCell  415  (e.g., may be transmitted to any cell, including the failed cell). 
     Accordingly, in some aspects UE  410  may configure the access message (e.g., BFR MAC CE) to indicate the CORESET pool index value associated with the detected beam failure. That is, the MAC CE may explicitly indicate the CORESET pool index value corresponding to the BFD. 
     In some aspects, UE  410  may configure the access message (e.g., BFR MAC CE) to indicate the beam failure was detected on the PCell  405 . In this example, UE  410  may transmit or otherwise convey the access message using a first set of random access resources associated with the first CORESET pool index value or using a second set of random access resources associated with the second CORESET pool index value. That is, the MAC CE may only indicate the BFD for PCell  405 , and the RACH resource/random access preamble index may implicitly determine (e.g., indicate) the CORESET pool index value associated with the BFD (e.g., and the q_new/new candidate beam for that CORESET pool index value). 
     At  450 , PCell  405  may transmit (and UE  410  may receive) a BFR response. In some aspects, the BFR response to the MAC CE may be an uplink grant scheduling a new transmission (e.g., with a toggled new data indicator (NDI)) for the same HARQ process as the PUSCH carrying the MAC CE. If the new candidate beam is reported in the BFR MAC CE, 28 symbols from the end of the BFR response (e.g., in the PDCCH), all CORESET beams on the failed cell (e.g., SCell  415 , or PCell  405  in this example), may be reset to the new candidate beam. If the failed cell is a PUCCH-SCell, the PUCCH-spatialRelationInfo may be configured. If the LLR is not transmitted on the failed cell, PUCCH beams on the failed cell may be reset to the new candidate beam. 
     In some aspects, this may include UE  410  monitoring for an access response message (e.g., the BFR response) on a first recovery search space configured with a first CORESET that is associated with the first CORESET pool index value or on a second recovery search space configured with a second CORESET that is associated with the second CORESET pool index value. That is, two different CORESETS may be associated with two different recovery search spaces (e.g., two recoverySearchSpaceIDs can be configured). The two CORESETs may be configured with different CORESET pool index values. A recoverySearchSpaceID may be associated with a CORESET pool index value through the corresponding CORESET. Accordingly, UE  410  may determine that the new candidate beam is associated with the first subset of candidate beams and monitor for an access response message (e.g., the BFR response) on the first recovery search space. Similarly, UE  410  may determine that the new candidate beam is associated with the second subset of candidate beams and monitor for an access response message (e.g., the BFR response) on the second recovery search space. UE  410  may receive a control channel signal (e.g., the access response message, or BFR response in this example) in the corresponding recovery search space and determine that the BFR procedure is complete based on receiving the control channel signal in the corresponding recovery search space. 
     In some aspects, only one CORESET may be used for BFR purposes. For example, UE  410  may monitor for the access response message (e.g., the BFR response) on a first recovery search space associated with the first CORESET pool index value or on a second recovery search space associated with the second CORESET pool index value. In this example, the first and second recovery search spaces may be associated with a common CORESET (e.g., the single CORESET used for BFR purposes). In one aspect, this may include two recoverySearchSpaceIDs being configured, both associated with the same CORESET. The first recovery search space (e.g., the first recoverySearchSpaceId) may be associated with the first CORESET pool index value (e.g., CORESETPoolIndex=0) and the second recovery search space (e.g., the second recoverySearchSpaceID) may be associated with the second CORESET pool index value (e.g., CORESETPoolIndex=1). This association between the second recovery search space and the second CORESET pool index value may be a direct association (e.g., not through the CORESET). 
       FIG.  5    shows a block diagram  500  of a device  505  that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. The device  505  may be an example of aspects of a UE  115  as described herein. The device  505  may include a receiver  510 , a communications manager  515 , and a transmitter  520 . The device  505  may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses). 
     The receiver  510  may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to BFR for a multi-TRP in a PCell, etc.). Information may be passed on to other components of the device  505 . The receiver  510  may be an example of aspects of the transceiver  820  described with reference to  FIG.  8   . The receiver  510  may utilize a single antenna or a set of antennas. 
     The communications manager  515  may receive a configuration for a carrier associated with a PCell, the carrier configured with a first CORESET pool index value and a second CORESET pool index value, receive an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams including a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value, select a new candidate beam from the set of candidate beams based on monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam, detect a beam failure on the carrier on an active beam of the PCell that is associated with the first CORESET pool index value or the second CORESET pool index value, and transmit an access message indicating the new candidate beam during the BFR procedure. The communications manager  515  may be an example of aspects of the communications manager  810  described herein. 
     The communications manager  515 , or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager  515 , or its sub-components may be executed by a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure. 
     The communications manager  515 , or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager  515 , or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager  515 , or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure. 
     The transmitter  520  may transmit signals generated by other components of the device  505 . In some examples, the transmitter  520  may be collocated with a receiver  510  in a transceiver module. For example, the transmitter  520  may be an example of aspects of the transceiver  820  described with reference to  FIG.  8   . The transmitter  520  may utilize a single antenna or a set of antennas. 
       FIG.  6    shows a block diagram  600  of a device  605  that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. The device  605  may be an example of aspects of a device  505 , or a UE  115  as described herein. The device  605  may include a receiver  610 , a communications manager  615 , and a transmitter  635 . The device  605  may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses). 
     The receiver  610  may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to BFR for a multi-TRP in a PCell, etc.). Information may be passed on to other components of the device  605 . The receiver  610  may be an example of aspects of the transceiver  820  described with reference to  FIG.  8   . The receiver  610  may utilize a single antenna or a set of antennas. 
     The communications manager  615  may be an example of aspects of the communications manager  515  as described herein. The communications manager  615  may include a CC configuration manager  620 , a candidate beam manager  625 , and a BFR manager  630 . The communications manager  615  may be an example of aspects of the communications manager  810  described herein. 
     The CC configuration manager  620  may receive a configuration for a carrier associated with a PCell, the carrier configured with a first CORESET pool index value and a second CORESET pool index value. 
     The candidate beam manager  625  may receive an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams including a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value and select a new candidate beam from the set of candidate beams based on monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam. 
     The BFR manager  630  may detect a beam failure on the carrier on an active beam of the PCell that is associated with the first CORESET pool index value or the second CORESET pool index value and transmit an access message indicating the new candidate beam during the BFR procedure. 
     The transmitter  635  may transmit signals generated by other components of the device  605 . In some examples, the transmitter  635  may be collocated with a receiver  610  in a transceiver module. For example, the transmitter  635  may be an example of aspects of the transceiver  820  described with reference to  FIG.  8   . The transmitter  635  may utilize a single antenna or a set of antennas. 
       FIG.  7    shows a block diagram  700  of a communications manager  705  that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. The communications manager  705  may be an example of aspects of a communications manager  515 , a communications manager  615 , or a communications manager  810  described herein. The communications manager  705  may include a CC configuration manager  710 , a candidate beam manager  715 , a BFR manager  720 , an access resource manager  725 , a BFR reporting manager  730 , a PCell BFR reporting manager  735 , a BFR response manager  740 , a QCL manager  745 , and a BFR procedure manager  750 . Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses). 
     The CC configuration manager  710  may receive a configuration for a carrier associated with a PCell, the carrier configured with a first CORESET pool index value and a second CORESET pool index value. In some examples, the CC configuration manager  710  may identify a first set of random access resources associated with the physical cell identifier and a second set of random access resources associated with the radio resource control configured physical cell identifier, where the access message is transmitted on the first set of random access resources or the second set of random access resources. 
     In some cases, the first CORESET pool index value is associated with a physical cell identifier associated with the PCell and the second CORESET pool index value is associated with a radio resource control configured physical cell identifier. In some cases, the resource includes a first set of candidate beam detection resources associated with the physical cell identifier and a second set of candidate beam detection resources associated with the radio resource control configured physical cell identifier. In some cases, the new candidate beam is associated with a synchronization signal block including an index of a second set of synchronization signal blocks. 
     The candidate beam manager  715  may receive an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams including a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value. In some examples, the candidate beam manager  715  may select a new candidate beam from the set of candidate beams based on monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam. 
     The BFR manager  720  may detect a beam failure on the carrier on an active beam of the PCell that is associated with the first CORESET pool index value or the second CORESET pool index value. In some examples, the BFR manager  720  may transmit an access message indicating the new candidate beam during the BFR procedure. 
     The access resource manager  725  may identify a first subset of random access resources associated with a first subset of candidate beam detection resources corresponding to the first subset of candidate beams and a second subset of random access resources associated with a second subset of candidate beam detection resources corresponding to the second subset of candidate beams, where the access message is transmitted based on the first set of random access resources or the second set of random access resources. 
     In some examples, the access resource manager  725  may receive an indication of a first set of random access resources associated with the first CORESET pool index value and a second set of random access resources associated with the second CORESET pool index value. In some examples, the access resource manager  725  may determine that the new candidate beam is associated with the first subset of candidate beams. In some examples, the access resource manager  725  may select a random access resource from the first set of random access resources that corresponds to the new candidate beam to transmit the access message. 
     The BFR reporting manager  730  may configure, based on the detected beam failure, the access message to indicate the first CORESET pool index value or the second CORESET pool index. 
     The PCell BFR reporting manager  735  may configure, based on the detected beam failure, the access message to indicate the beam failure was detected on the PCell. In some examples, the PCell BFR reporting manager  735  may transmit the access message using a first set of random access resources associated with the first CORESET pool index value or a second set of random access resources associated with the second CORESET pool index value. 
     The BFR response manager  740  may monitor for an access response message on a first recovery search space configured with a first CORESET that is associated with the first CORESET pool index value or on a second recovery search space configured with a second CORESET that is associated with the second CORESET pool index value. In some examples, the BFR response manager  740  may determine that the new candidate beam is associated with the first subset of candidate beams. In some examples, the BFR response manager  740  may monitor for the access response message on the first recovery search space. In some examples, the BFR response manager  740  may receive a control channel signal in the first recovery search space. In some examples, the BFR response manager  740  may determine that the BFR procedure is complete based on receiving the control channel signal in the first recovery search space. 
     In some examples, the BFR response manager  740  may monitor for an access response message on a first recovery search space associated with the first CORESET pool index value or on a second recovery search space associated with the second CORESET pool index value, the first recovery search space and the second recovery search space associated with a common CORESET. In some examples, the BFR response manager  740  may monitor for the access response message in the first recovery search space. In some examples, the BFR response manager  740  may determine that the new candidate beam is associated with the first CORESET pool index value or the second CORESET pool index value. 
     In some examples, the BFR response manager  740  may update, based on the determining, a CORESET pool index value of the common CORESET. In some examples, the BFR response manager  740  may update the CORESET pool index value of the common CORESET to correspond to the new candidate beam CORESET pool index value. 
     The QCL manager  745  may determine that the new candidate beam is associated with the first CORESET pool index value. In some examples, the QCL manager  745  may update, based on the determining, a quasi-location relationship for a CORESET with index 0, where the updated QCL relationship corresponds to a QCL configuration of the new candidate beam. In some examples, the QCL manager  745  may determine that the new candidate beam is associated with the first CORESET pool index value or the second CORESET pool index value. 
     In some examples, the QCL manager  745  may update, based on the determining, a quasi-location relationship for each control resource associated with the first CORESET pool index value or the second CORESET pool index value, where the updated QCL relationship corresponds to a QCL configuration of the new candidate beam. In some examples, the QCL manager  745  may update an activated set of transmission configuration indicator states for a data channel to a transmission configuration indicator state of the new candidate beam. 
     The BFR procedure manager  750  may determine that the beam failure on the active beam of the PCell is associated with the first CORESET pool index value, where the BFR procedure includes a PCell BFR procedure. In some examples, determining that the beam failure on the active beam of the PCell is associated with the second CORESET pool index value, where the BFR procedure includes a secondary cell BFR procedure. In some examples, the BFR procedure manager  750  may transmit a LRR message in an uplink control channel. In some examples, the BFR procedure manager  750  may receive, based on the LRR message, a grant scheduling an uplink transmission for the UE. In some examples, transmitting the uplink transmission that includes a MAC CE indicating the second CORESET pool index value of the PCell. 
       FIG.  8    shows a diagram of a system  800  including a device  805  that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. The device  805  may be an example of or include the components of device  505 , device  605 , or a UE  115  as described herein. The device  805  may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager  810 , an I/O controller  815 , a transceiver  820 , an antenna  825 , memory  830 , and a processor  840 . These components may be in electronic communication via one or more buses (e.g., bus  845 ). 
     The communications manager  810  may receive a configuration for a carrier associated with a PCell, the carrier configured with a first CORESET pool index value and a second CORESET pool index value, receive an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams including a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value, select a new candidate beam from the set of candidate beams based on monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam, detect a beam failure on the carrier on an active beam of the PCell that is associated with the first CORESET pool index value or the second CORESET pool index value, and transmit an access message indicating the new candidate beam during the BFR procedure. 
     The I/O controller  815  may manage input and output signals for the device  805 . The I/O controller  815  may also manage peripherals not integrated into the device  805 . In some cases, the I/O controller  815  may represent a physical connection or port to an external peripheral. In some cases, the I/O controller  815  may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operating system. In other cases, the I/O controller  815  may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller  815  may be implemented as part of a processor. In some cases, a user may interact with the device  805  via the I/O controller  815  or via hardware components controlled by the I/O controller  815 . 
     The transceiver  820  may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver  820  may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver  820  may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas. 
     In some cases, the wireless device may include a single antenna  825 . However, in some cases the device may have more than one antenna  825 , which may be capable of concurrently transmitting or receiving multiple wireless transmissions. 
     The memory  830  may include random access memory (RAM) and read-only memory (ROM). The memory  830  may store computer-readable, computer-executable code  835  including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory  830  may contain, among other things, a basic input/output system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices. 
     The processor  840  may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor  840  may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into the processor  840 . The processor  840  may be configured to execute computer-readable instructions stored in a memory (e.g., the memory  830 ) to cause the device  805  to perform various functions (e.g., functions or tasks supporting BFR for a multi-TRP in a PCell). 
     The code  835  may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code  835  may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code  835  may not be directly executable by the processor  840  but may cause a computer (e.g., when compiled and executed) to perform functions described herein. 
       FIG.  9    shows a block diagram  900  of a device  905  that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. The device  905  may be an example of aspects of a base station  105  as described herein. The device  905  may include a receiver  910 , a communications manager  915 , and a transmitter  920 . The device  905  may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses). 
     The receiver  910  may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to BFR for a multi-TRP in a PCell, etc.). Information may be passed on to other components of the device  905 . The receiver  910  may be an example of aspects of the transceiver  1220  described with reference to  FIG.  12   . The receiver  910  may utilize a single antenna or a set of antennas. 
     The communications manager  915  may transmit, to a UE, a configuration for a carrier associated with a PCell associated with the base station, the carrier configured with a first CORESET pool index value and a second CORESET pool index value, transmit an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams including a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value, and receive, based on the UE detecting a beam failure on the carrier on an active beam of the PCell associated with the first CORESET pool index value or the second CORESET pool index value, an access message indicating a new candidate beam, the new candidate beam selected from the set of candidate beams based on the UE monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam. The communications manager  915  may be an example of aspects of the communications manager  1210  described herein. 
     The communications manager  915 , or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager  915 , or its sub-components may be executed by a general-purpose processor, a DSP, an ASIC, a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure. 
     The communications manager  915 , or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager  915 , or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager  915 , or its sub-components, may be combined with one or more other hardware components, including but not limited to an I/O component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure. 
     The transmitter  920  may transmit signals generated by other components of the device  905 . In some examples, the transmitter  920  may be collocated with a receiver  910  in a transceiver module. For example, the transmitter  920  may be an example of aspects of the transceiver  1220  described with reference to  FIG.  12   . The transmitter  920  may utilize a single antenna or a set of antennas. 
       FIG.  10    shows a block diagram  1000  of a device  1005  that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. The device  1005  may be an example of aspects of a device  905 , or a base station  105  as described herein. The device  1005  may include a receiver  1010 , a communications manager  1015 , and a transmitter  1035 . The device  1005  may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses). 
     The receiver  1010  may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to BFR for a multi-TRP in a PCell, etc.). Information may be passed on to other components of the device  1005 . The receiver  1010  may be an example of aspects of the transceiver  1220  described with reference to  FIG.  12   . The receiver  1010  may utilize a single antenna or a set of antennas. 
     The communications manager  1015  may be an example of aspects of the communications manager  915  as described herein. The communications manager  1015  may include a CC configuration manager  1020 , a candidate beam manager  1025 , and a BFR manager  1030 . The communications manager  1015  may be an example of aspects of the communications manager  1210  described herein. 
     The CC configuration manager  1020  may transmit, to a UE, a configuration for a carrier associated with a PCell associated with the base station, the carrier configured with a first CORESET pool index value and a second CORESET pool index value. 
     The candidate beam manager  1025  may transmit an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams including a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value. 
     The BFR manager  1030  may receive, based on the UE detecting a beam failure on the carrier on an active beam of the PCell associated with the first CORESET pool index value or the second CORESET pool index value, an access message indicating a new candidate beam, the new candidate beam selected from the set of candidate beams based on the UE monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam. 
     The transmitter  1035  may transmit signals generated by other components of the device  1005 . In some examples, the transmitter  1035  may be collocated with a receiver  1010  in a transceiver module. For example, the transmitter  1035  may be an example of aspects of the transceiver  1220  described with reference to  FIG.  12   . The transmitter  1035  may utilize a single antenna or a set of antennas. 
       FIG.  11    shows a block diagram  1100  of a communications manager  1105  that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. The communications manager  1105  may be an example of aspects of a communications manager  915 , a communications manager  1015 , or a communications manager  1210  described herein. The communications manager  1105  may include a CC configuration manager  1110 , a candidate beam manager  1115 , a BFR manager  1120 , an access resource manager  1125 , a BFR response manager  1130 , a CORESET manager  1135 , a QCL manager  1140 , and a BFR procedure manager  1145 . Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses). 
     The CC configuration manager  1110  may transmit, to a UE, a configuration for a carrier associated with a PCell associated with the base station, the carrier configured with a first CORESET pool index value and a second CORESET pool index value. In some examples, the CC configuration manager  1110  may configure, for the UE, a first set of random access resources associated with the physical cell identifier and a second set of random access resources associated with the radio resource control configured physical cell identifier, where the access message is received on the first set of random access resources or the second set of random access resources. 
     In some cases, the first CORESET pool index value is associated with a physical cell identifier associated with the PCell and the second CORESET pool index value is associated with a radio resource control configured physical cell identifier. In some cases, the resource includes a first set of candidate beam detection resources associated with the physical cell identifier and a second set of candidate beam detection resources associated with the radio resource control configured physical cell identifier. In some cases, the new candidate beam is associated with a synchronization signal block including an index of a second set of synchronization signal blocks. 
     The candidate beam manager  1115  may transmit an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams including a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value. 
     The BFR manager  1120  may receive, based on the UE detecting a beam failure on the carrier on an active beam of the PCell associated with the first CORESET pool index value or the second CORESET pool index value, an access message indicating a new candidate beam, the new candidate beam selected from the set of candidate beams based on the UE monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam. In some examples, the BFR manager  1120  may receive the access message using a first set of random access resources associated with the first CORESET pool index value or a second set of random access resources associated with the second CORESET pool index value, where the access message indicates the beam failure was detected on the PCell. In some cases, the access message indicates the first CORESET pool index value or the second CORESET pool index. 
     The access resource manager  1125  may identify a first subset of random access resources associated with a first set of candidate beam detection resources corresponding to the first subset of candidate beams and a second subset of random access resources associated with the second set of candidate beam detection resources corresponding to the second subset of candidate beams, where the access message is received based on the first set of random access resources or the second set of random access resources. In some examples, the access resource manager  1125  may determine that the new candidate beam is associated with the first subset of candidate beams, where the access message is received on a random access resource selected from the first set of random access resources that corresponds to the new candidate beam. In some examples, the access resource manager  1125  may transmit an indication of a first set of random access resources associated with the first CORESET pool index value and a second set of random access resources associated with the second CORESET pool index value. 
     The BFR response manager  1130  may transmit an access response message on a first recovery search space configured with a first CORESET that is associated with the first CORESET pool index value or on a second recovery search space configured with a second CORESET that is associated with the second CORESET pool index value. In some examples, the BFR response manager  1130  may determine that the new candidate beam is associated with the first subset of candidate beams. In some examples, the BFR response manager  1130  may transmit the access response message on the first recovery search space. In some examples, the BFR response manager  1130  may transmit a control channel signal in the first recovery search space, where the BFR procedure is complete based on transmitting the control channel signal in the first recovery search space. 
     In some examples, the BFR response manager  1130  may transmit an access response message on a first recovery search space associated with the first CORESET pool index value or on a second recovery search space associated with the second CORESET pool index value, the first recovery search space and the second recovery search space associated with a common CORESET. In some examples, the BFR response manager  1130  may determine that the new candidate beam is associated with the first subset of candidate beams, where the access response message is transmitted in the first recovery search space. 
     The CORESET manager  1135  may update, based on the access message, a CORESET pool index value of the common CORESET. In some examples, the CORESET manager  1135  may update the CORESET pool index value of the common CORESET to correspond to the new candidate beam CORESET pool index value. 
     The QCL manager  1140  may update, based on the access message, a QCL relationship for a CORESET with index 0, where the updated QCL relationship corresponds to a QCL configuration of the new candidate beam. In some examples, the QCL manager  1140  may update, based on the access message, a quasi-location relationship for each control resource associated with the first CORESET pool index value or the second CORESET pool index value, where the updated QCL relationship corresponds to a QCL configuration of the new candidate beam. In some examples, the QCL manager  1140  may update an activated set of transmission configuration indicator states for a data channel to a transmission configuration indicator state of the new candidate beam. 
     The BFR procedure manager  1145  may determine that the beam failure on the active beam of the PCell is associated with the first CORESET pool index value, where the BFR procedure includes a PCell BFR procedure. In some examples, determining that the beam failure on the active beam of the PCell is associated with the second CORESET pool index value, where the BFR procedure includes a secondary cell BFR procedure. In some examples, the BFR procedure manager  1145  may receive a LRR message in an uplink control channel. In some examples, the BFR procedure manager  1145  may transmit, based on the LRR message, a grant scheduling an uplink transmission for the UE. In some examples, receiving the uplink transmission that includes a MAC CE indicating the second CORESET pool index value of the PCell. 
       FIG.  12    shows a diagram of a system  1200  including a device  1205  that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. The device  1205  may be an example of or include the components of device  905 , device  1005 , or a base station  105  as described herein. The device  1205  may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager  1210 , a network communications manager  1215 , a transceiver  1220 , an antenna  1225 , memory  1230 , a processor  1240 , and an inter-station communications manager  1245 . These components may be in electronic communication via one or more buses (e.g., bus  1250 ). 
     The communications manager  1210  may transmit, to a UE, a configuration for a carrier associated with a PCell associated with the base station, the carrier configured with a first CORESET pool index value and a second CORESET pool index value, transmit an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams including a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value, and receive, based on the UE detecting a beam failure on the carrier on an active beam of the PCell associated with the first CORESET pool index value or the second CORESET pool index value, an access message indicating a new candidate beam, the new candidate beam selected from the set of candidate beams based on the UE monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam. 
     The network communications manager  1215  may manage communications with the core network (e.g., via one or more wired backhaul links). For example, the network communications manager  1215  may manage the transfer of data communications for client devices, such as one or more UEs  115 . 
     The transceiver  1220  may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver  1220  may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver  1220  may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas. 
     In some cases, the wireless device may include a single antenna  1225 . However, in some cases the device may have more than one antenna  1225 , which may be capable of concurrently transmitting or receiving multiple wireless transmissions. 
     The memory  1230  may include RAM, ROM, or a combination thereof. The memory  1230  may store computer-readable code  1235  including instructions that, when executed by a processor (e.g., the processor  1240 ) cause the device to perform various functions described herein. In some cases, the memory  1230  may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices. 
     The processor  1240  may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor  1240  may be configured to operate a memory array using a memory controller. In some cases, a memory controller may be integrated into processor  1240 . The processor  1240  may be configured to execute computer-readable instructions stored in a memory (e.g., the memory  1230 ) to cause the device  1205  to perform various functions (e.g., functions or tasks supporting BFR for a multi-TRP in a PCell). 
     The inter-station communications manager  1245  may manage communications with other base station  105 , and may include a controller or scheduler for controlling communications with UEs  115  in cooperation with other base stations  105 . For example, the inter-station communications manager  1245  may coordinate scheduling for transmissions to UEs  115  for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communications manager  1245  may provide an X2 interface within an LTE/LTE-A wireless communication network technology to provide communication between base stations  105 . 
     The code  1235  may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code  1235  may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code  1235  may not be directly executable by the processor  1240  but may cause a computer (e.g., when compiled and executed) to perform functions described herein. 
       FIG.  13    shows a flowchart illustrating a method  1300  that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. The operations of method  1300  may be implemented by a UE  115  or its components as described herein. For example, the operations of method  1300  may be performed by a communications manager as described with reference to  FIGS.  5  through  8   . In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware. 
     At  1305 , the UE may receive a configuration for a carrier associated with a PCell, the carrier configured with a first CORESET pool index value and a second CORESET pool index value. The operations of  1305  may be performed according to the methods described herein. In some examples, aspects of the operations of  1305  may be performed by a CC configuration manager as described with reference to  FIGS.  5  through  8   . 
     At  1310 , the UE may receive an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams including a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value. The operations of  1310  may be performed according to the methods described herein. In some examples, aspects of the operations of  1310  may be performed by a candidate beam manager as described with reference to  FIGS.  5  through  8   . 
     At  1315 , the UE may detect a beam failure on the carrier on an active beam of the PCell that is associated with the first CORESET pool index value or the second CORESET pool index value. The operations of  1315  may be performed according to the methods described herein. In some examples, aspects of the operations of  1315  may be performed by a BFR manager as described with reference to  FIGS.  5  through  8   . 
     At  1320 , the UE may select a new candidate beam from the set of candidate beams based on monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam. The operations of  1320  may be performed according to the methods described herein. In some examples, aspects of the operations of  1320  may be performed by a candidate beam manager as described with reference to  FIGS.  5  through  8   . 
     At  1325 , the UE may transmit an access message indicating the new candidate beam during the BFR procedure. The operations of  1325  may be performed according to the methods described herein. In some examples, aspects of the operations of  1325  may be performed by a BFR manager as described with reference to  FIGS.  5  through  8   . 
       FIG.  14    shows a flowchart illustrating a method  1400  that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. The operations of method  1400  may be implemented by a UE  115  or its components as described herein. For example, the operations of method  1400  may be performed by a communications manager as described with reference to  FIGS.  5  through  8   . In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware. 
     At  1405 , the UE may receive a configuration for a carrier associated with a PCell, the carrier configured with a first CORESET pool index value and a second CORESET pool index value. The operations of  1405  may be performed according to the methods described herein. In some examples, aspects of the operations of  1405  may be performed by a CC configuration manager as described with reference to  FIGS.  5  through  8   . 
     At  1410 , the UE may receive an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams including a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value. The operations of  1410  may be performed according to the methods described herein. In some examples, aspects of the operations of  1410  may be performed by a candidate beam manager as described with reference to  FIGS.  5  through  8   . 
     At  1415 , the UE may detect a beam failure on the carrier on an active beam of the PCell that is associated with the first CORESET pool index value or the second CORESET pool index value. The operations of  1415  may be performed according to the methods described herein. In some examples, aspects of the operations of  1415  may be performed by a BFR manager as described with reference to  FIGS.  5  through  8   . 
     At  1420 , the UE may select a new candidate beam from the set of candidate beams based on monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam. The operations of  1420  may be performed according to the methods described herein. In some examples, aspects of the operations of  1420  may be performed by a candidate beam manager as described with reference to  FIGS.  5  through  8   . 
     At  1425 , the UE may identify a first subset of random access resources associated with a first subset of candidate beam detection resources corresponding to the first subset of candidate beams and a second subset of random access resources associated with a second subset of candidate beam detection resources corresponding to the second subset of candidate beams, where the access message is transmitted based on the first set of random access resources or the second set of random access resources. The operations of  1425  may be performed according to the methods described herein. In some examples, aspects of the operations of  1425  may be performed by an access resource manager as described with reference to  FIGS.  5  through  8   . 
     At  1430 , the UE may transmit an access message indicating the new candidate beam during the BFR procedure. The operations of  1430  may be performed according to the methods described herein. In some examples, aspects of the operations of  1430  may be performed by a BFR manager as described with reference to  FIGS.  5  through  8   . 
       FIG.  15    shows a flowchart illustrating a method  1500  that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. The operations of method  1500  may be implemented by a UE  115  or its components as described herein. For example, the operations of method  1500  may be performed by a communications manager as described with reference to  FIGS.  5  through  8   . In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware. 
     At  1505 , the UE may receive a configuration for a carrier associated with a PCell, the carrier configured with a first CORESET pool index value and a second CORESET pool index value. The operations of  1505  may be performed according to the methods described herein. In some examples, aspects of the operations of  1505  may be performed by a CC configuration manager as described with reference to  FIGS.  5  through  8   . 
     At  1510 , the UE may receive an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams including a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value. The operations of  1510  may be performed according to the methods described herein. In some examples, aspects of the operations of  1510  may be performed by a candidate beam manager as described with reference to  FIGS.  5  through  8   . 
     At  1515 , the UE may detect a beam failure on the carrier on an active beam of the PCell that is associated with the first CORESET pool index value or the second CORESET pool index value. The operations of  1515  may be performed according to the methods described herein. In some examples, aspects of the operations of  1515  may be performed by a BFR manager as described with reference to  FIGS.  5  through  8   . 
     At  1520 , the UE may select a new candidate beam from the set of candidate beams based on monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam. The operations of  1520  may be performed according to the methods described herein. In some examples, aspects of the operations of  1520  may be performed by a candidate beam manager as described with reference to  FIGS.  5  through  8   . 
     At  1525 , the UE may transmit an access message indicating the new candidate beam during the BFR procedure. The operations of  1525  may be performed according to the methods described herein. In some examples, aspects of the operations of  1525  may be performed by a BFR manager as described with reference to  FIGS.  5  through  8   . 
     At  1530 , the UE may monitor for an access response message on a first recovery search space configured with a first CORESET that is associated with the first CORESET pool index value or on a second recovery search space configured with a second CORESET that is associated with the second CORESET pool index value. The operations of  1530  may be performed according to the methods described herein. In some examples, aspects of the operations of  1530  may be performed by a BFR response manager as described with reference to  FIGS.  5  through  8   . 
       FIG.  16    shows a flowchart illustrating a method  1600  that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. The operations of method  1600  may be implemented by a base station  105  or its components as described herein. For example, the operations of method  1600  may be performed by a communications manager as described with reference to  FIGS.  9  through  12   . In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware. 
     At  1605 , the base station may transmit, to a UE, a configuration for a carrier associated with a PCell associated with the base station, the carrier configured with a first CORESET pool index value and a second CORESET pool index value. The operations of  1605  may be performed according to the methods described herein. In some examples, aspects of the operations of  1605  may be performed by a CC configuration manager as described with reference to  FIGS.  9  through  12   . 
     At  1610 , the base station may transmit an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams including a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value. The operations of  1610  may be performed according to the methods described herein. In some examples, aspects of the operations of  1610  may be performed by a candidate beam manager as described with reference to  FIGS.  9  through  12   . 
     At  1615 , the base station may receive, based on the UE detecting a beam failure on the carrier on an active beam of the PCell associated with the first CORESET pool index value or the second CORESET pool index value, an access message indicating a new candidate beam, the new candidate beam selected from the set of candidate beams based on the UE monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam. The operations of  1615  may be performed according to the methods described herein. In some examples, aspects of the operations of  1615  may be performed by a BFR manager as described with reference to  FIGS.  9  through  12   . 
       FIG.  17    shows a flowchart illustrating a method  1700  that supports BFR for a multi-TRP in a PCell in accordance with aspects of the present disclosure. The operations of method  1700  may be implemented by a base station  105  or its components as described herein. For example, the operations of method  1700  may be performed by a communications manager as described with reference to  FIGS.  9  through  12   . In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware. 
     At  1705 , the base station may transmit, to a UE, a configuration for a carrier associated with a PCell associated with the base station, the carrier configured with a first CORESET pool index value and a second CORESET pool index value. The operations of  1705  may be performed according to the methods described herein. In some examples, aspects of the operations of  1705  may be performed by a CC configuration manager as described with reference to  FIGS.  9  through  12   . 
     At  1710 , the base station may transmit an indication of a first set of random access resources associated with the first CORESET pool index value and a second set of random access resources associated with the second CORESET pool index value. The operations of  1710  may be performed according to the methods described herein. In some examples, aspects of the operations of  1710  may be performed by an access resource manager as described with reference to  FIGS.  9  through  12   . 
     At  1715 , the base station may transmit an indication of a set of candidate beams available for a BFR procedure, the set of candidate beams including a first subset of candidate beams associated with the first CORESET pool index value and a second subset of candidate beams associated with the second CORESET pool index value. The operations of  1715  may be performed according to the methods described herein. In some examples, aspects of the operations of  1715  may be performed by a candidate beam manager as described with reference to  FIGS.  9  through  12   . 
     At  1720 , the base station may receive, based on the UE detecting a beam failure on the carrier on an active beam of the PCell associated with the first CORESET pool index value or the second CORESET pool index value, an access message indicating a new candidate beam, the new candidate beam selected from the set of candidate beams based on the UE monitoring a resource associated with the first CORESET pool index value or the second CORESET pool index value, the resource mapped to the new candidate beam. The operations of  1720  may be performed according to the methods described herein. In some examples, aspects of the operations of  1720  may be performed by a BFR manager as described with reference to  FIGS.  9  through  12   . 
     It should be noted that the methods described herein describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined. 
     Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR networks. For example, the described techniques may be applicable to various other wireless communication systems such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, as well as other systems and radio technologies not explicitly mentioned herein. 
     Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. 
     The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration). 
     The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. 
     Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include random-access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media. 
     As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of”) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on.” 
     In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label. 
     The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “example” used herein means “serving as an example, instance, or illustration,” and not “preferred” or “advantageous over other examples.” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples. 
     The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.