Physical uplink control channel beam failure recovery configuration

Certain aspects of the present disclosure provide techniques for configuring beam failure recovery operations. A method includes performing beam failure detection of a beam pair link associated with a secondary cell, wherein a user equipment (UE) is configured with one or more uplink control channel groups, each of the one or more uplink control channel groups comprising a corresponding plurality of component carriers where one of the corresponding plurality of component carriers is designated for communication of an uplink control channel for the corresponding uplink control channel group; determining one or more cells on which to send a beam failure recovery request (BFRQ) message based on a number of uplink control channel groups the UE is configured with; sending the BFRQ on the one or more cells; and receiving a beam failure recovery response message on at least one of the one or more cells.

BACKGROUND

Field of the Disclosure

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for configuring beam failure recovery (BFR) operations for a physical uplink control channel (PUCCH) cell (PUCCH-Cell) of a PUCCH group.

Description of Related Art

SUMMARY

Certain aspects of the present disclosure provide a method for wireless communication by a user equipment (UE). The method generally includes performing beam failure detection (BFD) of a beam pair link (BPL) associated with a first secondary cell (SCell) in carrier aggregation (CA), wherein the UE is configured with one or more uplink control channel groups for communication, each of the one or more uplink control channel groups comprising a corresponding plurality of component carriers where one of the corresponding plurality of component carriers is designated for communication of an uplink control channel for the corresponding uplink control channel group; determining one or more cells on which to send a beam failure recovery request (BFRQ) message based on a number of uplink control channel groups the UE is configured with; sending the BFRQ on the one or more cells; and receiving a beam failure recovery response (BFRR) message on at least one of the one or more cells.

Certain aspects of the present disclosure provide a UE comprising a memory and a processor coupled to the memory. The processor and memory are configured to perform beam failure detection (BFD) of a beam pair link (BPL) associated with a first secondary cell (SCell) in carrier aggregation (CA), wherein the UE is configured with one or more uplink control channel groups for communication, each of the one or more uplink control channel groups comprising a corresponding plurality of component carriers where one of the corresponding plurality of component carriers is designated for communication of an uplink control channel for the corresponding uplink control channel group. The processor and memory are configured to determine one or more cells on which to send a beam failure recovery request (BFRQ) message based on a number of uplink control channel groups the UE is configured with. The processor and memory are configured to send the BFRQ on the one or more cells. The processor and memory are configured to receive a beam failure recovery response (BFRR) message on at least one of the one or more cells.

Certain aspects of the present disclosure provide a UE comprising means for performing beam failure detection (BFD) of a beam pair link (BPL) associated with a first secondary cell (SCell) in carrier aggregation (CA), wherein the UE is configured with one or more uplink control channel groups for communication, each of the one or more uplink control channel groups comprising a corresponding plurality of component carriers where one of the corresponding plurality of component carriers is designated for communication of an uplink control channel for the corresponding uplink control channel group. The UE further comprises means for determining one or more cells on which to send a beam failure recovery request (BFRQ) message based on a number of uplink control channel groups the UE is configured with. The UE further comprises means for sending the BFRQ on the one or more cells. The UE further comprises means for receiving a beam failure recovery response (BFRR) message on at least one of the one or more cells.

Certain aspects of the present disclosure provide a non-transitory computer-readable storage medium that stores instructions that when executed by a processor of a user equipment (UE) cause the UE to perform a method. The method generally includes performing beam failure detection (BFD) of a beam pair link (BPL) associated with a first secondary cell (SCell) in carrier aggregation (CA), wherein the UE is configured with one or more uplink control channel groups for communication, each of the one or more uplink control channel groups comprising a corresponding plurality of component carriers where one of the corresponding plurality of component carriers is designated for communication of an uplink control channel for the corresponding uplink control channel group; determining one or more cells on which to send a beam failure recovery request (BFRQ) message based on a number of uplink control channel groups the UE is configured with; sending the BFRQ on the one or more cells; and receiving a beam failure recovery response (BFRR) message on at least one of the one or more cells.

Aspects of the present disclosure provide means for, apparatus, processors, and computer-readable mediums for performing the methods described herein.

DETAILED DESCRIPTION

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for configuring beam failure recovery (BFR) operations for a physical uplink control channel (PUCCH) cell (PUCCH-Cell) of a PUCCH group. In some wireless communication systems (e.g., 5G NR), a UE may be configured to communicate with a base station via multiple cells (e.g., a primary cell (PCell) and at least one secondary cell (SCell)) served by multiple component carriers (CC), which may be referred to as carrier aggregation (CA). In certain cases, the UE may only receive downlink data transmissions via the SCell. For example, the UE may receive downlink control signaling from the PCell (e.g., scheduling resource grants, radio resource control (RRC) signaling, downlink control information (DCI)) on a control resource set (CORESET) of a physical downlink control channel (PDCCH) and receive only downlink data transmissions from the SCell (e.g., on a physical downlink shared channel (PDSCH)), which may be configured without a CORESET for which to receive control signaling. In other cases, the UE may communicate with the SCell on both an uplink and a downlink.

In some cases, a UE may be configured to transmit control information, such as, physical uplink control channels (PUCCHs), for a group of component carriers via a common component carrier. In these cases, the group of component carriers may be referred to as an uplink control channel group, or a PUCCH group, and the common component carrier may be referred to as an uplink control carrier or PUCCH-Cell for the associated PUCCH group.

In some cases, when a UE is configured with one PUCCH group, then the PUCCH-Cell may be required to be a PCell or a primary secondary cell (PSCell, i.e., the primary cell for a secondary cell group) for the UE. When a UE is configured with multiple (e.g., 2) PUCCH groups, the PUCCH-Cell of a first PUCCH group may be required to be a PCell or PSCell, while the PUCCH-Cell of a second PUCCH group may be an SCell.

In certain systems, beam failure recovery may be configured for one or more of the uplink SCells of a UE, depending on a number of uplink control channel groups that are configured on the UE.

The techniques described herein may be used for various wireless networks and radio technologies me. For clarity, while aspects may be described herein using terminology commonly associated with 3G, 4G, and/or new radio (e.g., 5G NR) wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems.

Certain wireless networks utilize orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system bandwidth. The system bandwidth may also be partitioned into subbands.

5G NR may utilize OFDM with a cyclic prefix (CP) on the uplink and downlink and include support for half-duplex operation using time division duplexing (TDD). A subframe can be 1 ms, but the basic transmission time interval (TTI) may be referred to as a slot. A subframe contains a variable number of slots (e.g., 1, 2, 4, 8, 16, . . . slots) depending on the subcarrier spacing (SCS). The NR resource block (RB) may be 12 consecutive frequency subcarriers. NR may support a base SCS of 15 KHz and other subcarrier spacing may be defined with respect to the base SCS, for example, 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc. The symbol and slot lengths scale with the SCS. The CP length also depends on the SCS. 5G NR may also support beamforming and beam direction may be dynamically configured. Multiple-input multiple-output (MIMO) transmissions with precoding may also be supported. In some examples, MIMO configurations in the DL may support up to 8 transmit antennas with multi-layer DL transmissions up to 8 streams and up to 2 streams per UE. In some examples, multi-layer transmissions with up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported with up to 8 serving cells.

FIG. 1illustrates an example wireless communication network100in which aspects of the present disclosure may be performed. For example, the wireless communication network100may be an NR system (e.g., a 5G NR network).

According to certain aspects, the UEs120may be configured for configuring PUCCH-BFR for a PUCCH-Cell of a PUCCH group. As shown inFIG. 1, the UE120aincludes a PUCCH BFR manager122. The PUCCH BFR manager122may be configured to perform beam failure detection (BFD) of a beam pair link (BPL) associated with a first secondary cell (SCell) in carrier aggregation (CA). The UE120ais configured with one or more uplink control channel groups for communication, each of the one or more uplink control channel groups comprising a corresponding plurality of component carriers where one of the corresponding plurality of component carriers is designated for communication of an uplink control channel for the corresponding uplink control channel group. The PUCCH BFR manager122is further configured to determine one or more cells to which to send a beam failure recovery request (BFRQ) message based on a number of uplink control channel groups the UE is configured with. The PUCCH BFR manager122is further configured to send the BFRQ to the one or more cells. The PUCCH BFR manager122is further configured to receive a beam failure recovery response (BFRR) message from at least one of the one or more cells, in accordance with aspects of the present disclosure.

Wireless communication network100may also include relay stations (e.g., relay station110r), also referred to as relays or the like, that receive a transmission of data and/or other information from an upstream station (e.g., a BS110aor a UE120r) and sends a transmission of the data and/or other information to a downstream station (e.g., a UE120or a BS110), or that relays transmissions between UEs120, to facilitate communication between devices.

A network controller130may couple to a set of BSs110and provide coordination and control for these BSs110. The network controller130may communicate with the BSs110via a backhaul. The BSs110may also communicate with one another (e.g., directly or indirectly) via wireless or wireline backhaul.

FIG. 2illustrates example components of BS110aand UE120a(e.g., in the wireless communication network100ofFIG. 1), which may be used to implement aspects of the present disclosure.

At the BS110a, a transmit processor220may receive data from a data source212and control information from a controller/processor240. The control information may be for the physical broadcast channel (PBCH), physical control format indicator channel (PCFICH), physical hybrid ARQ indicator channel (PHICH), physical downlink control channel (PDCCH), group common PDCCH (GC PDCCH), etc. The data may be for the physical downlink shared channel (PDSCH), etc. A medium access control (MAC)-control element (MAC-CE) is a MAC layer communication structure that may be used for control command exchange between wireless nodes. For example, a base station may transmit a MAC CE to a user-equipment (UE) to put the UE into a discontinuous reception (DRX) mode to reduce the UE' s power consumption. The MAC-CE may be carried in a shared channel such as a physical downlink shared channel (PDSCH), a physical uplink shared channel (PUSCH), or a physical sidelink shared channel. A MAC-CE may also be used to communicate information that facilitates communication, such as information regarding buffer status and available power headroom.

The memories242and282may store data and program codes for BS110aand UE120a, respectively. A scheduler244may schedule UEs for data transmission on the downlink and/or uplink.

The controller/processor280and/or other processors and modules at the UE120amay perform or direct the execution of processes for the techniques described herein. As shown inFIG. 2, the controller/processor280of the UE120ahas a PUCCH BFR manager281that may be configured for performing beam failure detection (BFD) of a beam pair link (BPL) associated with a first secondary cell (SCell) in carrier aggregation (CA). The UE120ais configured with one or more uplink control channel groups for communication, each of the one or more uplink control channel groups comprising a corresponding plurality of component carriers where one of the corresponding plurality of component carriers is designated for communication of an uplink control channel for the corresponding uplink control channel group. The PUCCH BFR manager281is further configured to determine one or more cells to which to send a beam failure recovery request (BFRQ) message based on a number of uplink control channel groups the UE is configured with. The PUCCH BFR manager281is further configured to send the BFRQ to the one or more cells. The PUCCH BFR manager281is further configured to receive a beam failure recovery response (BFRR) message from at least one of the one or more cells, in accordance with aspects of the present disclosure. Although shown at the controller/processor, other components of the UE120aand BS110amay be used to perform the operations described herein.

Certain systems, such as NR, support carrier aggregation (CA). With CA, the UE can use multiple carriers/cells to communicate with a BS (or multiple BSs). CA involves a primary cell (PCell) and at least one secondary cell (SCell). An SCell may configured for downlink only, or configured for both uplink and downlink. The PCell and SCell(s) can be in different frequency bands, such as a PCell in one frequency range (e.g., FR1, sub-6 GHz) and the SCell in another frequency range (FR2, 28 GHz). The PCell and SCell may use different tone spacing or subcarrier spacing (SCS), leading to different symbol lengths for the PCell and SCell(s). For example, in the F1 the symbols length for a 120 KHz SCS is eight times shorter than a symbol length for a 15 kHz SCS in FR1.

As mentioned above, aspects of the present disclosure relate to beam failure detection and recovery. In some systems, narrow-beam transmission and reception is useful for improving the link budget at millimeter-wave (mmW) frequencies but may be susceptible to beam failure. In mmW, directional beamforming is used between the UE and a BS, and the UE and BS communicate via a beam pair link (BPL) (e.g., a receive beam on the receiver side and a transmit beam on the transmitter side). A beam failure generally refers to a scenario in which the quality of a beam falls below a threshold, which may lead to radio link failure (RLF). NR supports a lower layer signaling to recover from beam failure, referred to as beam recovery. For example, instead of initiating a cell reselection when a beam quality becomes too low, a beam pair reselection within the cell may be performed.

FIG. 3is a call flow300of an example beam failure detection and recovery procedure, in accordance with certain aspects of the present disclosure. Beam failure may be detected by monitoring a beam failure detection (BFD) reference signal (RS) and assessing if a beam failure trigger condition has been met (e.g., measured strength/quality of the BFD RS is below a threshold). As shown inFIG. 3, the UE302(e.g., corresponding to UE120aofFIG. 1) monitors, at308, the BFD RS from the SCell304. In some examples, beam failure detection is triggered if an estimated block error rate (BLER) of reference signals associated with a configured control resource set (CORESET) is above a threshold (e.g., 10%). In some examples, the UE302detects beam failure when the reference signal receive power (RSRP) of a BPL is below a threshold.

To recover the SCell304, the UE302can send a beam failure request (BFRQ) message on the same or another cell. In certain aspects, the SCell304on which beam failure is detected by the UE on the downlink can also be used to send the BFRQ as the uplink may still be viable, even if the downlink has failed on the SCell304. In some examples, the BFRQ is sent on the PCell306, as shown inFIG. 3. In NR systems, a two-step BFRQ may be used. The BFRQ may request a new transmission. As shown inFIG. 3, after detecting beam failure, the UE302sends the first step (or first stage) of the BFRQ at310. The first step of the BFRQ message may include a scheduling request (SR) on the PCell306. The SR may be sent on dedicated SR resources. The SR may request scheduling for the second step (or second stage) of the BFRQ message. As shown inFIG. 3, at312, the UE302may receive a PDCCH from the PCell306, in response to the SR, scheduling the second set of the BFRQ message. The UE302then sends the scheduled second step of the BFRQ message at314on the PCell306. For example, the UE302sends a PUSCH including a MAC-CE, as shown inFIG. 3. The MAC-CE may include an index of the failed CC and a new recovery beam candidate beam. In some examples, to find candidate new beams, the UE may monitor a beam identification reference signal.

At316, the PCell306responds to the BFRQ by transmitting a beam failure recovery response (BFRR) message to the UE302, as shown inFIG. 3. The BFRR message may acknowledge the MAC-CE and include an uplink grant scheduling a new transmission. For example, the uplink grant may schedule a transmission for the same hybrid automatic repeat request (HARD) process as the PUSCH carrying the MAC-CE in the step two of the BFRQ. In some examples, the BFRR is sent over a CORESET (e.g., referred to as a CORESET-BFR) the UE302monitors for the response.

If the response is received successfully, the beam recovery is completed and a new BPL may be established. If the UE302cannot detect any response within a specific time period, the UE302may perform a retransmission of the request. If the UE302cannot detect any response after a specified number of retransmissions, then the UE302may notify higher layers, potentially leading to RLF and cell reselection.

After receiving the BFRR, at316, and before the new BPL is established, the UE302may communicate on the SCell304using a default beam.

As mentioned above, in some wireless communication systems (e.g., 5G NR), a UE may be configured to communicate with a base station via multiple cells (e.g., a primary cell (PCell) and at least one secondary cell (SCell)) served by multiple component carriers (CC), which may be referred to as carrier aggregation (CA). In certain cases, the UE may only receive downlink data transmissions via the SCell. For example, the UE may receive downlink control signaling from the PCell (e.g., scheduling resource grants, radio resource control (RRC) signaling, downlink control information (DCI)) on a control resource set (CORESET) of a PDCCH and receive only downlink data transmissions from the SCell, which may be configured without a CORESET for which to receive control signaling. In other cases, the UE may communicate with the SCell on both the uplink and downlink.

In some cases, a UE may be configured to transmit physical uplink control channels (PUCCHs) for a group of component carriers via a common component carrier. In these cases, the group of component carriers may be referred to as a PUCCH group, and the common component carrier may be referred to as a PUCCH-Cell for the associated PUCCH group.

In some cases, when a UE is configured with one PUCCH group, then the PUCCH-Cell may be required to be a PCell or a primary secondary cell (PSCell, i.e., the primary cell for a secondary cell group) for the UE. When a UE is configured with 2 PUCCH groups, the PUCCH-Cell of a first PUCCH group may be required to be a PCell or PSCell, while the PUCCH-Cell of a second PUCCH group may be an SCell.

Techniques and apparatus for the UE and BS (associated with the SCell) to determine when and how to configure beam failure recovery on PUCCH-Cells for PUCCH groups are desirable.

Example Physical Uplink Control Channel Beam Failure Recovery Configuration

According to some aspects of the present disclosure, when a UE is configured with multiple (e.g., 2) PUCCH groups, then PUCCH beam failure recovery (PUCCH-BFR) may be configurable on PUCCH-Cells for each of the PUCCH groups, but may not be configurable on other uplink cells (e.g., SCells) of the PUCCH groups. In certain such aspects, by limiting the cells on which PUCCH-BFR occurs to PUCCH-Cells, a BS does not need to process signals on other uplink cells for potential PUCCH-BFR, thereby reducing some processing complexity at the BS. Such aspects may also reduce bandwidth usage of such other uplink cells, leaving more bandwidth for use of such other uplink cells for other uplink communications.

In some aspects of the present disclosure, when a UE is configured with multiple (e.g., 2) PUCCH groups, then PUCCH-BFR may be configurable on PUCCH-Cells for each of the PUCCH groups and on other uplink SCells of the PUCCH groups. PUCCH-BFR may be configured on all or a subset of SCells of the PUCCH groups. In certain such aspects, this may decrease bandwidth usage of the PUCCH-Cells as PUCCH-BFR can be sent on a larger set of uplink cells, thereby leaving more bandwidth of the PUCCH-Cells available for use for communicating other uplink control information, such as for other UEs.

According to some aspects of the present disclosure, a total number of SCells that can be configured with PUCCH-BFR for a UE configured with multiple PUCCH groups may be a fixed number (e.g., 1). The fixed number may be pre-defined in a communications standard or network configuration.

In some aspects of the present disclosure, a total number of SCells that may be configured with PUCCH-BFR for a UE configured with multiple PUCCH groups may be a fixed number per frequency band used for communication on the uplink by the UE.

According to some aspects of the present disclosure, a total number of SCells that may be configured with PUCCH-BFR for a UE configured with multiple PUCCH groups may be any number up to a maximum capability for that UE.

In some aspects of the present disclosure, when a UE is configured with only one PUCCH group, then PUCCH-BFR may not be configured on any SCell of the UE. PUCCH-BFR may be configured on the PUCCH-Cell, which is a PCell or PSCell. In certain such aspects, by limiting the cell on which PUCCH-BFR occurs to the PUCCH-Cell, a BS does not need to process signals on other uplink cells for potential PUCCH-BFR, thereby reducing some processing complexity at the BS. Such aspects may also reduce bandwidth usage of such other uplink cells, leaving more bandwidth for use of such other uplink cells for other uplink communications.

According to some aspects of the present disclosure, when a UE is configured with only one PUCCH group, then PUCCH-BFR may be configured on the PUCCH-Cell and also on other SCells. The other SCells with PUCCH-BFR configured may be all SCells or a subset of SCells. In certain such aspects, this may decrease bandwidth usage of the PUCCH-Cells as PUCCH-BFR can be sent on a larger set of uplink cells, thereby leaving more bandwidth of the PUCCH-Cells available for use for communicating other uplink control information, such as for other UEs.

In some aspects of the present disclosure, a total number of SCells that may be configured with PUCCH-BFR for a UE configured with one PUCCH group may be a fixed number (e.g., 1). The fixed number may be pre-defined in a communications standard or network configuration.

According to some aspects of the present disclosure, a total number of SCells that may be configured with PUCCH-BFR for a UE configured with one PUCCH group may be a fixed number per frequency band used for communication on the uplink by the UE.

In some aspects of the present disclosure, a total number of SCells that may be configured with PUCCH-BFR for a UE configured with 1 PUCCH group may be any number up to a maximum capability for that UE.

FIG. 4is a call flow illustrating example operations400for configuring PUCCH-BFR for a PUCCH-Cell of a PUCCH group, in accordance with certain aspects of the present disclosure. As shown, at406, a UE120may optionally transmit on the PCell404, to a base station (e.g., the BS110a), an indication of a maximum number of SCells on which the UE120can have BFR configured. That is, the UE120may optionally provide the base station with the maximum number of SCells that the UE can monitor concurrently for beam failure. At408, the base station may transmit to the UE120on the PCell404a configuration of PUCCH-BFR for the SCell402, which may be designated for communication of an uplink control channel for an uplink control channel group.

At410, the UE120may determine one or more cells on which to send a beam failure recovery request (BFRQ) message based on a number of uplink control channel groups the UE is configured with.

At414, the UE120may receive data transmissions on the SCell402.

At420, the UE120may detect a beam failure. At422, the UE120sends the BFRQ on the one or more cells.

At424, the UE120receives a beam failure recovery response (BFRR) message on at least one of the one or more cells.

FIG. 5is a flow diagram illustrating example operations500for wireless communication, in accordance with certain aspects of the present disclosure. The operations500may be performed, for example, by UE (e.g., such as a UE120ain the wireless communication network100). Operations500may be implemented as software components that are executed and run on one or more processors (e.g., controller/processor280ofFIG. 2). Further, the transmission and reception of signals by the UE in operations500may be enabled, for example, by one or more antennas (e.g., antennas252ofFIG. 2). In certain aspects, the transmission and/or reception of signals by the UE may be implemented via a bus interface of one or more processors (e.g., controller/processor280) obtaining and/or outputting signals.

The operations500may begin, at505, by performing beam failure detection (BFD) of a beam pair link (BPL) associated with a first secondary cell (SCell) in carrier aggregation (CA), wherein the UE is configured with one or more uplink control channel groups (e.g., PUCCH groups) for communication, each of the one or more uplink control channel groups comprising a corresponding plurality of component carriers where one (e.g., PUCCH-Cell) of the corresponding plurality of component carriers is designated for communication of an uplink control channel (e.g., PUCCH) for the corresponding uplink control channel group (e.g., PUCCH group).

At510, the UE determines one or more cells on which to send a beam failure recovery request (BFRQ) message based on a number of uplink control channel groups the UE is configured with.

At515, the UE sends the BFRQ on the one or more cells.

At520, the UE receives a beam failure recovery response (BFRR) message on at least one of the one or more cells.

According to certain aspects, the BFRQ comprises a scheduling request on the at least one of the one or more cells.

In some examples, if the number of uplink control channel groups is one, the one (e.g., PUCCH-Cell) of the corresponding plurality of component carriers designated for communication of the uplink control channel is a primary cell of the UE. For example, when a UE is configured with only one PUCCH group, then the PUCCH-Cell may be required to be a PCell or a primary secondary cell (PSCell, i.e., the primary cell for a secondary cell group) for the UE. In some examples, if the number of uplink control channel groups is greater than one, the one (e.g., PUCCH-Cell) of the corresponding plurality of component carriers designated for communication of the uplink control channel is the primary cell for one of the one or more uplink control channel groups, and the one (e.g., PUCCH-Cell) of the corresponding plurality of component carriers designated for communication of the uplink control channel is the primary cell or a secondary cell for each of one or more remaining uplink control channel groups. For example, when a UE is configured with multiple PUCCH groups, the PUCCH-Cell of a first PUCCH group may be required to be a PCell or PSCell, while the PUCCH-Cell of a second PUCCH group may be an SCell.

According to certain aspects, the number of uplink control channel groups is one, and the one or more cells comprises one or more secondary cells of the UE based on the number being one. For example, when a UE is configured with only one PUCCH group, then PUCCH-BFR may be configured on the PUCCH-Cell and also on other SCells. The other SCells with PUCCH-BFR configured may be all SCells or a subset of SCells. In some examples, a number of the one or more secondary cells is fixed (e.g., 1). This may reduce signaling complexity. In some examples, a number of the one or more secondary cells is based on a number of frequency bands the UE is configured to communicate in. For example, the greater the number of frequency bands the UE is configured to communicate in, the greater the number of secondary cells there may be across such a greater number of frequency bands. For example, the number of the one or more secondary cells may equal or be a multiple of the number of frequency bands the UE is configured to communicate in. In some examples, a number of the one or more secondary cells is based on a UE capability of the UE, such how many SCells the UE is able to support.

According to certain aspects, the number of uplink control channel groups is greater than one, and the one or more cells consist of one or more of the ones (e.g., PUCCH-Cells) of the corresponding plurality of component carriers designated for communication of the uplink control channel based on the number being greater than one. For example, in the case where the UE is configured with multiple (e.g., 2) PUCCH groups, then PUCCH-BFR may be configurable on PUCCH-Cells for each of the PUCCH groups, but may not be configurable on other uplink cells (e.g., SCells) of the PUCCH groups.

According to certain aspects, the number of uplink control channel groups is greater than one, and the one or more cells comprises one or more secondary cells that are not the ones (e.g., PUCCH-Cells) of the corresponding plurality of component carriers designated for communication of the uplink control channel of the UE based on the number being greater than one. For example, when a UE is configured with multiple (e.g., 2) PUCCH groups, then PUCCH-BFR may be configurable on PUCCH-Cells for each of the PUCCH groups and on other uplink SCells of the PUCCH groups. PUCCH-BFR may be configured on all or a subset of SCells of the PUCCH groups. In some examples, a number of the one or more secondary cells is fixed (e.g., 1). This may reduce signaling complexity. In some examples, a number of the one or more secondary cells is based on a number of frequency bands the UE is configured to communicate in. For example, the greater the number of frequency bands the UE is configured to communicate in, the greater the number of secondary cells there may be across such a greater number of frequency bands. For example, the number of the one or more secondary cells may equal or be a multiple of the number of frequency bands the UE is configured to communicate in. In some examples, a number of the one or more secondary cells is based on a UE capability of the UE, such how many SCells the UE is able to support.

In aspects of the present disclosure, the one (e.g., PUCCH-Cell) of the corresponding plurality of component carriers that is designated for communication of the uplink control channel for the corresponding uplink control channel group is used for transmitting the uplink control channel for all purposes, such as for all types of uplink control information (e.g., channel state information (CSI) feedback, acknowledgement (ACK), and/or regular SR). This is in contrast to other aspects, where the component carrier used for communication of the uplink control channel is only used to transmit some types of uplink control information (e.g., CSI feedback) and not other types of uplink control information (e.g., ACK).

FIG. 6illustrates a communications device600that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated inFIG. 5. The communications device600includes a processing system602coupled to a transceiver608(e.g., a transmitter and/or a receiver). The transceiver608is configured to transmit and receive signals for the communications device600via an antenna610, such as the various signals as described herein. The processing system602may be configured to perform processing functions for the communications device600, including processing signals received and/or to be transmitted by the communications device600.

The processing system602includes a processor604coupled to a computer-readable medium/memory612via a bus606. In certain aspects, the computer-readable medium/memory612is configured to store instructions (e.g., computer-executable code) that when executed by the processor604, cause the processor604to perform the operations illustrated inFIG. 5, or other operations for performing the various techniques discussed herein for PUCCH-BFR configuration on an SCell. In certain aspects, computer-readable medium/memory612stores code614for performing beam failure detection (BFD) of a beam pair link (BPL) associated with a first secondary cell (SCell) in carrier aggregation (CA), wherein the UE is configured with one or more uplink control channel groups for communication, each of the one or more uplink control channel groups comprising a corresponding plurality of component carriers where one of the corresponding plurality of component carriers is designated for communication of an uplink control channel for the corresponding uplink control channel group; code616for determining one or more cells on which to send a beam failure recovery request (BFRQ) message based on a number of uplink control channel groups the UE is configured with; code618for sending the BFRQ on the one or more cells; and code620for receiving a beam failure recovery response (BFRR) message on at least one of the one or more cells, in accordance with aspects of the present disclosure. In certain aspects, the processor604has circuitry configured to implement the code stored in the computer-readable medium/memory612. The processor604includes circuitry622for performing beam failure detection (BFD) of a beam pair link (BPL) associated with a first secondary cell (SCell) in carrier aggregation (CA), wherein the UE is configured with one or more uplink control channel groups for communication, each of the one or more uplink control channel groups comprising a corresponding plurality of component carriers where one of the corresponding plurality of component carriers is designated for communication of an uplink control channel for the corresponding uplink control channel group; circuitry624for determining one or more cells on which to send a beam failure recovery request (BFRQ) message based on a number of uplink control channel groups the UE is configured with; circuitry626for sending the BFRQ on the one or more cells; and circuitry628for receiving a beam failure recovery response (BFRR) message on at least one of the one or more cells, in accordance with aspects of the present disclosure.