Abstract: This disclosure provides systems, methods, and apparatuses for determining whether a channel state information reference signal (CSI-RS) is to be transmitted, and a configuration for transmission of the CSI-RS on a wideband based on an outcome of a listen-before-talk (LBT) operation in multiple sub-bands of the wideband. In one aspect, a base station may transmit sub-band usage information indicating sub-band availability before the CSI-RS, thereby allowing a user equipment (UE) to determine whether the CSI-RS will be transmitted and, if so, on which sub-bands the CSI-RS will be transmitted. Furthermore, rate matching configurations are provided based on whether sub-band usage has been received, based on which sub-bands are available. Still further, power configurations and resource element selection criteria are provided for wideband CSI-RS and CSI feedback.

Abstract: Configurations for configured grant (CG) in new radio unlicensed (NR-U) systems is disclosed. CG configurations may, based on a periodicity, be provided either using a bitmap, shorter periodicity, or resource indicator value (RIV) signaling of start/end symbols, longer periodicity. Such CG configurations configure M sets of time division resource allocations. CG configuration may include common start/end symbols from for all contiguous allocations in one configuration. Common LBT starting points may be defined for all configured slots as indicated through a bitmap. The CG configuration allows for mini- and full slot configurations, in which the mini-slots are configured within the already configured CG slots. Repetition configurations include a type 1 for coverage and a type 2 for faster retransmission and reduced downlink feedback information (DFI) overhead. With multiple UEs, a UE identifier is added to the uplink control information (UCI). UEs may further ramp up power in the absence of DFI.

Abstract: Certain aspects of the present disclosure relate to a method and apparatus for receiving a medium occupation and a resource block group (RBG) size from a gNB, wherein the radio block group size is based on a bandwidth part (BWP) configuration. In one example, UEs with smaller BWP have finer granularity in RBG size in terms of PRBs, while UEs with larger BWP may have a coarser granularity in RBG size in terms of PRBs. An additional guard band may be used if the gNB reserves some channels such that not all of the BW is occupied. For example, if the gNB reserves the 20 MHz channel, it may perform better by adding additional guard band on each side of the 20 MHz bandwidth to accommodate an adjacent channel leakage-power ratio (ACLR). Another aspect of the present disclosure relates to assigning a UE an interlace with equally spaced PRBs.

Abstract: Methods, systems, and devices for wireless communications are described. A wireless communications system may support grants for uplink or downlink transmission over multiple transmission time intervals (TTIs). A multi-TTI grant may include a base grant and an extended grant that include separate information and may be transmitted simultaneously (e.g., within the same TTI) or separately. A grant type (e.g., whether a grant is a base grant or an extended grant) or an association between a base grant and an extended grant may be conveyed (e.g., via the multi-TTI grant). A downlink assignment index (DAI) may be included for one or more TTIs subject to the multi-TTI. For instance, DAI may be included for each TTI or for a subset of TTIs.

Abstract: Wireless communications systems and methods related to communicating a structure of a channel occupancy time (COT) are provided. A first wireless communication device communicates with a second wireless communication device, a first indicator indicating at least one of a subband configuration for a COT or a duration of the COT. The first wireless communication device communicates with the second wireless communication device during the COT, a first communication signal based on at least one of the subband configuration for the COT or the duration of the COT. The first wireless communication device communicates with the second wireless communication device during the COT, a second indicator indicating an update for at least one of the subband configuration for the COT or the duration of the COT. Additionally, the first wireless communication device communicates with the second wireless communication device during the COT, a second communication signal based on the update.

Abstract: Techniques and devices for wireless communications are described that provide for staggering sounding reference signal (SRS) transmissions in frequency across multiple orthogonal frequency division multiplexing (OFDM) symbols, which may allow multiple UEs to transmit SRS using a common listen-before-talk (LBT) gap for a LBT procedure. The techniques also provide for transmitting an SRS across multiple OFDM symbols using same frequency resources, and an orthogonal cover code (OCC) may be applied to the SRS transmission of each OFDM symbol, which may allow multiple UEs to transmit concurrent SRS using a common LBT gap.

Abstract: Techniques for defining a reference duration and one or more reference transmissions that are utilized for contention window update are provided to address these new features. An apparatus, such as a wireless device, determines a reference duration of a channel occupancy time (COT), the reference duration based at least in part on a subcarrier spacing (SCS) and based on reception of a physical downlink shared channel (PDSCH) transmission. The apparatus updates a contention window (CW) based at least in part on reception of the PDSCH transmission during the reference duration. For example, the apparatus may increase the CW when a negative acknowledgement (NACK) is received for the determined PDSCH in the COT and may assign CW with a predetermined minimum value (CW_min) when a positive acknowledgement (ACK) is received for the determined PDSCH.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a configuration that indicates a number of bits to be used in an indication of at least one of a listen-before-talk (LBT) category or a channel access priority class to be used for uplink communications. The UE may receive the indication of at least one of the LBT category or the channel access priority class to be used for a transmission starting point associated with one or more uplink communications, wherein the indication includes the number of bits indicated in the configuration. The UE may perform an LBT procedure for an uplink communication, of the one or more uplink communications, transmitted at the transmission starting point, according to the LBT category or the channel access priority class. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) and base station may communicate in on a wireless channel of an unlicensed radio frequency spectrum band. The base station may transmit synchronization signal blocks (SSBs) in a discovery reference signal (DRS) slot. The base station may multiplex a channel state information (CSI) reference signal (CSI-RS). The base station may multiplex an aperiodic CSI-RS or a periodic CSI-RS with the SSBs in the DRS slot. For an aperiodic CSI-RS, the base station may separately trigger the CSI-RS measurement and CSI-RS reporting. For periodic CSI-RS, the base station may transmit an indication of whether the periodic CSI-RS is present.

Abstract: Wireless communications systems and methods related to signaling transmission starting offsets for uplink transmissions in a frequency spectrum shared by multiple network operating entities are provided. A first wireless communication device communicates, with a second wireless communication device, a cyclic prefix (CP) extension length configuration for providing a gap duration for a listen-before-talk (LBT) associated with a first communication signal. The first wireless communication device communicates, with the second wireless communication device, the first communication signal including a CP extension having a length based on the CP extension length configuration.

Abstract: This disclosure provides systems, methods, and apparatuses for determining whether a channel state information reference signal (CSI-RS) is to be transmitted, and a configuration for transmission of the CSI-RS on a wideband based on an outcome of a listen-before-talk (LBT) operation in multiple sub-bands of the wideband. In one aspect, a base station may transmit sub-band usage information indicating sub-band availability before the CSI-RS, thereby allowing a user equipment (UE) to determine whether the CSI-RS will be transmitted and, if so, on which sub-bands the CSI-RS will be transmitted. Furthermore, rate matching configurations are provided based on whether sub-band usage has been received, based on which sub-bands are available. Still further, power configurations and resource element selection criteria are provided for wideband CSI-RS and CSI feedback.

Abstract: This disclosure provides systems, methods, and apparatus, including computer programs encoded on computer storage media, for group reference signal triggering for contention-based systems. The described techniques may enable a network node to trigger a group of one or more user equipments (UEs) to transmit a reference signal to the network node. The network node may transmit a group common control channel indicating timing information or configuration information corresponding to a set of resources for the transmission of the reference signal. The one or more UEs may transmit the reference signal according to the timing information or configuration information.

Abstract: Methods, systems, and devices for wireless communications are described that support group-based acknowledgment feedback techniques. Two or more different groups of downlink transmissions may each have an associated transport block (TB) level or code block group (CBG) level group-based acknowledgment feedback, and a base station may transmit downlink control information to a UE that indicates one or more parameters that are used to determine which downlink transmissions are to be reported in the group-based feedback at a TB level, CBG level, or combinations thereof. Based on the parameters in the downlink control information, the UE may determine the feedback to be reported, and a timing for when to transmit the feedback to the base station.

Abstract: Techniques are described herein for improved methods, systems, devices, and apparatuses that support procedures for configured grants. Generally, the described techniques may relate to restricting a number of retransmissions used during a hybrid automatic repeat request (HARQ) process or managing potential scheduling conflicts for the HARQ process from dynamic grants and configured grants. A device (e.g., a user equipment) may initiate a timer or a counter associated with a HARQ process for indicating that transmission attempts for the HARQ process are permitted. The device may identify a transmission occasion of a configured grant in an unlicensed frequency spectrum band that is associated with the HARQ process and may determine that the timer associated with the HARQ process is active. The device may perform a transmission attempt over the transmission occasion of the configured grant based on determining that the timer is active.

Abstract: A user equipment (UE) may receiving, from a base station, a synchronization signal block (SSB) of a set of quasi-collocated (QCL) SSBs, the SSB comprising an indication of a parameter indicating information associated with a plurality of downlink control channel locations corresponding to the set of QCL SSBs. The UE may determine, based at least in part on the parameter, the plurality of downlink control channel locations corresponding to the set of QCL SSBs. The UE may receive a downlink grant for a system information based at least in part on monitoring one or more downlink control channel locations of the plurality of downlink control channel locations. The UE may receive the system information based at least in part on the downlink grant. The UE may establish a connection with the base station based at least in part on the SSB and the received system information.

Abstract: Wireless communications systems and methods related to performing listen-before-talk (LBT) before a transmission after a link switch in a frequency spectrum shared by multiple network operating entities are provided. A first wireless communication device receives, from a second wireless communication device, a first communication signal. The first wireless communication device determines a first measurement period in a first portion of a gap duration between the first communication signal and a second communication signal, the first portion being adjacent to a start time of the second communication signal. The first wireless communication device performs an LBT based at least in part on a first channel measurement in the first measurement period. The first wireless communication device transmits, to the second wireless communication device, the second communication signal based on the LBT.

Abstract: Methods, systems, and devices for wireless communications are described for managing sounding reference signal (SRS) transmissions in shared radio frequency spectrum. Described techniques provide for increased occasions at which a SRS may be transmitted, enhance likelihood of a successful listen-before-talk (LBT) procedure, or any combinations thereof. Increased occasions for SRS may be provided through multiple transmission times that are available in the event of an earlier LBT failure. Enhanced likelihood of successful LBT may be provided through one or more timing offsets that may be randomly selected from a set of available timing offsets, selection of a cyclic prefix length for a SRS based on whether the SRS transmission is within or outside of a channel occupancy time of a base station, providing an initial SRS transmission time for an initial periodic time interval, triggering of an aperiodic SRS within the channel occupancy time, or any combinations thereof.

Abstract: Hybrid automatic repeat request (HARQ)-acknowledgement (ACK) feedback codebook enhancements are disclosed. A size of feedback codebook may be reduced explicitly or implicitly. For example, an indicator may be identified by a corresponding field of a downlink control message. In some aspects, the indicator may indicate that multiple Physical Downlink or Uplink Shared Channels (PDSCHs/PUSCHs) are actually scheduled during one or more slots of a window corresponding to the feedback codebook. Responsive to receiving the indicator, a device may refrain from reducing the size of the feedback codebook to exclude acknowledgement feedback for additional possible PDSCH/PUSCH occasions of the slots of the window. In some aspects, a device identifies possible PDSCH/PUSCH occasions that occur outside of one or more Channel Occupancy Times (COTs) of a window. The device may generate a reduced size feedback codebook by excluding the possible PDSCH/PUSCH occasions that occur outside of the COTs of the window.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) and base station may communicate in on a wireless channel of an unlicensed radio frequency spectrum band. The base station may transmit synchronization signal blocks (SSBs) in a discovery reference signal (DRS) slot. The base station may multiplex a channel state information (CSI) reference signal (CSI-RS). The base station may multiplex an aperiodic CSI-RS or a periodic CSI-RS with the SSBs in the DRS slot. For an aperiodic CSI-RS, the base station may separately trigger the CSI-RS measurement and CSI-RS reporting. For periodic CSI-RS, the base station may transmit an indication of whether the periodic CSI-RS is present.

Abstract: Methods, systems, and devices for wireless communication are described. Some wireless communications systems may support a determination of user equipment (UE) capabilities, such as a category or a coverage level for broadcast or multicast content. In some cases, a radio interface may be configured to account for an indicated capability of a target UE. For example, a base station may receive an indication of a capability of a particular targeted UE. The capability of the targeted UE may be specified by a service provider to deliver multicast or broadcast content, and subsequently associated with a radio interface between the base station and the target UE. The radio interface may then be configured based on the indicated capability of the target UE, for example, by configuring a transport block size or bandwidth. The base station may then transmit broadcast or multicast content to the UE using the configured radio interface.