Abstract: New radio (NR) shared spectrum (NR-SS) listen before talk (LBT) gap optimizations are disclosed in which an indication, such as the preemption indicator, may provide an indication of a communications gap, in which preemptive communications may occur, to a user equipment (UE) currently engaged in communications, whether the preemptive communications are to another UE or network node or through different signal channels. The gap and preemptive communication may be measured in full symbol lengths, sub-symbol lengths, or interlaces. The communication gap may provide sufficient resources for the preempting node to adequately obtain the shared channel via listen before talk (LBT) procedures, and for the original UE to resume communications after the gap. The communication gap may also be optimally configured in order to provide both the UE and preempting node as much communication resources as possible within the scheduled communication opportunities.

Abstract: Methods, systems, and devices for wireless communications are described in which a user equipment (UE) may be configured with one or more semi-persistent scheduling (SPS) configurations. A base station may transmit a first downlink control information (DCI) transmission to the UE that activates an SPS configuration, and the first DCI may indicate a non-numeric feedback timeline for reporting associated acknowledgment feedback. The base station may transmit a subsequent second DCI transmission that provides feedback resources, and the UE may receive the second DCI and identify timing and resources for SPS acknowledgment feedback based on the second DCI. The UE may then transmit the acknowledgment feedback for one or more SPS transmissions in the feedback resources that are indicated by the second DCI transmission.

Abstract: Wireless communications systems and methods related to unscheduled uplink hybrid automatic repeat request (HARQ) data transmissions in a shared radio frequency band are provided. A user equipment (UE) determine priorities for a plurality of transport blocks (TBs) associated with a plurality of hybrid automatic repeat request (HARQ) processes for transmission during configured transmission periods. The UE transmits, to a base station (BS), the plurality of TBs in a shared radio frequency band during the configured transmission periods based on the determined priorities.

Abstract: Methods, systems, and devices for wireless communications in unlicensed spectrum are described. In some wireless communications systems, a user equipment may identify a service parameter configured for the user equipment for a shared radio frequency channel, such as a subcarrier spacing or beam direction for a directional beam for communications with a base station. The base station may acquire a channel occupancy time for the shared radio frequency channel. The user equipment may monitor for and receive a control message for the channel occupancy time from the base station. The control message may include an indication of service associated with the service parameter and a remaining duration of the channel occupancy time. Based on the indications, the user equipment may adapt one or more receive parameters (e.g., a monitoring periodicity, monitoring time occasions, and whether to skip monitoring) for communicating with the base station during the channel occupancy time.

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: Wireless communications systems and methods related to communicating positioning reference signals (PRSs) for narrowband communication are provided. A first wireless communication device determines a time-frequency PRS pattern based at least in part on a narrowband communication frequency band configuration and a PRS subframe configuration mode associated with a set of subframes. The first wireless communication device communicates, with a second wireless communication device, a plurality of PRSs using the determined PRS time-frequency pattern in the set of subframes. The PRS subframe configuration mode can indicate a first configuration including a bitmap indicating a set of PRS subframes positioned within a group of contiguous subframes, a second configuration indicating a subset of the group of contiguous subframes that may carry the PRSs, or a combination thereof. The first configuration and/or the second configuration can be used to indicate the set of subframes.

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.