Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) and a base station may communicate in an unlicensed spectrum (e.g., a shared radio frequency spectrum band). As such, the UE may determine a codebook size for transmitting hybrid access request (HARQ) acknowledgement (ACK) feedback with respect to the unlicensed spectrum. Accordingly, the UE may base the HARQ ACK codebook size on a number of HARQ processes with which the UE has been configured. Additionally or alternatively, the UE may base the HARQ ACK codebook size on a number and/or duration of downlink channel monitoring occasions indicated by the base station. In some cases, the UE may base the HARQ ACK codebook size on a combination of the techniques described herein.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may indicate support of an extended cyclic prefix (ECP), where a duration of the ECP or transmitting the ECP is based on the indication. In some cases, the UE may receive an uplink grant to transmit an uplink message with an indication of the ECP, and the UE may transmit the ECP and uplink message according to a timeline based in part on the ECP. Additionally or alternatively, an uplink channel allocation indicated in the uplink grant may include a starting point for the ECP, where the UE transmits the ECP at the starting point. In some cases, the UE may multiplex uplink control information (UCI) in the uplink channel based on a timeline that is based in part on the ECP.

Abstract: Hybrid automatic repeat request (HARQ) acknowledgement (ACK) feedback enhancements are disclosed for new radio (NR) unlicensed (NR-U). In the downlink control channel, two sets of identifiers (IDs) may be explicitly or implicitly signaled. The two IDs identify a current set ID and an additional set ID. Where the two IDs match, then the ACK feedback transmitted in the current ACK message will reflect the current transmissions. Otherwise, where the two IDs are different, the additional set ID identifies any previous or different ACK information that should be transmitted for prior transmissions.

Abstract: Random access channel access and validity procedures are disclosed. In one aspect, the medium access control (MAC) indications multiple random access occasions (ROs) to user equipments (UEs) for random access transmissions. In such aspect, random access failure would only be declared if listen before talk (LBT) procedures for the random access transmission fail on all of the ROs indicated by the MAC layer. Similarly, in additional aspects, a UE will not apply a backoff value for any LBT failures for random access attempts that occur within an LBT time window. In further aspects, a UE may determine the validity of ROs that overlap with a discovery reference signal measurement timing configuration (DMTC) window. In such aspects, the UE may not use overlapping ROs or may determine a portion of the DMTC window that is not used for base station transmissions and declare the overlapping ROs with the unused portion valid.

Abstract: Methods, systems, and devices for wireless communications are described that enable efficient group-based acknowledgment feedback reporting. Techniques are provided for feedback for a number of different downlink transmissions to be reported by a user equipment (UE) using transport block level feedback, code block group level feedback, or combinations thereof. Acknowledgment feedback may be provided in one or more group-based or enhanced dynamic feedback reports, a one-shot feedback report, or any combinations thereof.

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 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. 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: This disclosure provides systems, methods and apparatus for a user equipment (UE), operating in a shared spectrum in a connected state or an idle state, to receive a channel occupancy time structure information (COT-SI) which includes one or more of a COT duration, a COT end symbol, and a COT pause indication, in addition to slot format indication for one or more slots. Some aspects described herein define a hierarchical approach to COT structure information (COT-SI) signaling. For example, a UE may be configured with a set of short COT tables using remaining minimum system information (RMSI) signaling and may receive concatenation of COT-SI signaling identifying index values in a control channel corresponding to one or more of the set of COT tables. Based on receiving COT-SI signaling, the UE may communicate in accordance with an occurrence of a COT.

Abstract: Wireless communications systems and methods are provided. A method of wireless communication may include performing a first listen-before-talk (LBT) procedure associated with a channel, wherein a channel occupancy time (COT) for the channel is acquired based on the first LBT being successful, communicating a first communication signal in a first link direction during the COT, switching from the first link direction to a second link direction different from the first link direction, and communicating after the switching, a second communication signal in the second link direction without performing a second LBT.

Abstract: This disclosure provides systems, methods, and apparatuses for the identification of a channel state information reference signal (CSI-RS) resource. In some aspects, a UE that receives the CSI-RS may determine CSI feedback based at least in part on the CSI-RS after detecting the CSI-RS resource that includes the CSI-RS. Signaling or techniques for when no CSI-RS is detected (such as when the base station fails a channel access operation for all available CSI-RS resources) are also provided. Furthermore, approaches for rate matching for a shared channel around CSI-RS resources or for CSI interference management (CSI-IM) resources are provided, as well as CSI reporting approaches for cases when the UE fails to transmit CSI feedback due to a failed channel access operation, such as a triggered or re-triggered CSI report.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may indicate support of an extended cyclic prefix (ECP), where a duration of the ECP or transmitting the ECP is based on the indication. In some cases, the UE may receive an uplink grant to transmit an uplink message with an indication of the ECP, and the UE may transmit the ECP and uplink message according to a timeline based in part on the ECP. Additionally or alternatively, an uplink channel allocation indicated in the uplink grant may include a starting point for the ECP, where the UE transmits the ECP at the starting point. In some cases, the UE may multiplex uplink control information (UCI) in the uplink channel based on a timeline that is based in part on the ECP.

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: Wireless communications systems and methods related to system information communications and decoding are provided. In one embodiment, a wireless communication device receives one or more known bits. The wireless communication device receives a first encoded information block. The wireless communication device decodes the first encoded information block to generate a first information block based on the one or more known bits. In one embodiment, a wireless communication device receives a first encoded information block including a first bit pattern. The wireless communication device receives a second encoded information block including a second bit pattern. The wireless communication device jointly decodes the first encoded information block and the second encoded information block based on an assumption that a difference between the first bit pattern and the second bit pattern is within a subset of a plurality of bit-change patterns.

Abstract: Wireless communications systems and methods related user multiplexing with discrete Fourier transform (DFT) precoded frequency interlaces are provided. A first wireless communication device identifies a first block-spreading code from a set of block-spreading codes associated with user multiplexing. The first wireless communication device communicates, with a second wireless communication device using a frequency interlace in a frequency spectrum, a first communication signal including a first block of information symbols spread across a set of resource blocks (RBs) within the frequency interlace based on the first block-spreading code. The first communication signal is generated by block-spreading the first block of information symbols based on the first block-spreading code to produce a first block of spread information symbols, performing a DFT on the first block of spread information symbols, and mapping the first block of spread information symbols to the set of RBs.

Abstract: Wireless communications systems and methods related to improving multiplexing capability in a frequency spectrum are provided. A first wireless communication device obtains a configuration for communicating a communication signal in a frequency spectrum. The configuration is based on at least a number of wireless communication devices scheduled to communicate in a time period. The configuration indicates resources in the frequency spectrum over the time period and a frequency distribution mode of the resources. The first wireless communication device communicates, with a second wireless communication device, the communication signal in the frequency spectrum during the time period based on the configuration.

Abstract: Wireless communications systems and methods related to downlink control channel communications in a wireless communication network are provided. A first wireless communication device communicates, with a second wireless communication device, a configuration indicating a first group of one or more search spaces and a second group of one or more search spaces, where at least one of the first group or the second group includes at least one search space not included in an other of the first group or the second group. The first wireless communication device communicates, with the second wireless communication device, a first downlink control information (DCI) message in a first search space of the first group of one or more search spaces. The first wireless communication device communicates, with the second wireless communication device, a second DCI message in a second search space of the second group of one or more search spaces.

Abstract: Coverage enhancements and coverage mode switching related optimizations are discussed for user equipments (UEs) that may switch between various coverage extension (CE) and non-CE modes of operation. In such enhancements, paging uncertainty and delays may be reduced by sending pages either simultaneously or using historical information over multiple coverage modes available to UEs. Random access procedures may be improved by providing CE mode random access procedures that are available when normal mode random access attempts fail and before declaring radio link failure. Additional aspects include improvements for more advanced UEs to improve coverage within normal mode operations by leveraging techniques used for narrowband CE mode operations, including transmission repetition and gapless transmission scheduling over hopped narrowband frequencies.

Abstract: Wireless communications systems and methods are provided. A method of wireless communication may include performing a first listen-before-talk (LBT) procedure associated with a channel, wherein a channel occupancy time (COT) for the channel is acquired based on the first LBT being successful, communicating a first communication signal in a first link direction during the COT, switching from the first link direction to a second link direction different from the first link direction, and communicating after the switching, a second communication signal in the second link direction without performing a second LBT.

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: Configured grant operations for new radio (NR) unlicensed spectrum (NR-U) carrier aggregation (CA) are disclosed. In an aspect, a method of wireless communication by a user equipment (UE) may include transmitting uplink (UL) data to a base station according to a configured grant configuration. The method may also include determining a carrier to receive feedback from the base station based on the configured grant configuration. The method may further include receiving feedback from the base station on the carrier in response to the transmitting of the UL data.

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 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. 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.