Abstract: Methods, systems, and devices for wireless communication are described. Data may be received during transmission time intervals (TTIs) that have a short duration relative to other TTIs. The short-duration TTIs may occur within or overlap a longer duration TTI, such as a subframe. Feedback responsive to the data may be generated and assigned for transmission during an uplink TTI according to a feedback timing or delay, which may be selected to reduce latency or balance the payload size of uplink messages sent during the assigned uplink TTI. Data and feedback assignments in short-duration TTIs may be configured based on a time division duplexing (TDD) configuration for some TTIs (e.g., subframes). TTIs that are a Long Term Evolution (LTE) subframe, an LTE slot, and a duration of two LTE symbol periods may be supported. Portions of special TTIs may be used for transmissions according to shorter-duration TTIs.

Abstract: Methods, systems, and devices for wireless communications are described. The described techniques generally support downlink transmissions. For example, a user equipment (UE) may receive a resource configuration for reception of a downlink transmission within a repetition window, the resource configuration including an indicator of a repetition window size for the downlink transmission. The UE may monitor, according to the resource configuration, one or more transmission time intervals (TTIs) of the repetition window for reception of the downlink transmission. In some cases, the downlink transmission may be a grant-free downlink transmission. Here, the UE may attempt to decode the grant-free downlink transmission during the one or more TTIs based at least in part on the repetition window size.

Abstract: Methods, systems, and devices for wireless communications are described. A frequency band configuration for a full-duplex slot may be indicated, where a frequency band configuration may include one or more downlink frequency bands and one or more uplink frequency bands. In some cases, a frequency band configuration may also include one or more guard bands. A user equipment (UE) may determine the frequency band configuration for a full-duplex slot based on a frequency configuration indication, which may include an index for a table of frequency band configurations, one or more bitmaps, or respective start and length indications for each frequency band. A frequency band configuration may apply to one slot or to multiple slots.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may interleave a signal, that is to be transmitted using discrete Fourier transform (DFT) spread orthogonal frequency-division multiplexing (DFT-s-OFDM), and a negative of the signal to obtain an interleaved signal prior to performing a DFT on the interleaved signal. The UE may transmit a DFT-s-OFDM signal that is based at least in part on the interleaved signal. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communications are described in which a base station may identify a null space matrix that lies within a null space of an effective channel matrix for communications between the base station and a user equipment (UE). An indication of the null space matrix may be provided to the UE, and the null space matrix used to determine modifications to a precoding matrix. The base station and UE may determine a redistribution matrix that provides a reduced variance of transmission powers for a number of transmission channels, where a product of the null space matrix and the redistribution matrix may be computed and added to the precoding matrix to generate a modified precoding matrix. The modified precoding matrix may be used to generate the communications from the base station and UE with reduced power variance across channels.

Abstract: Methods, systems, and devices for wireless communication are described. A user equipment (UE) may transmit uplink (UL) messages in unlicensed spectrum with a reduced UL timing delay. The UL timing delay may be reduced by using a shortened transmission time interval (TTI) (e.g., a TTI that is reduced in duration relative to other TTIs in the system or in a legacy system) or by reducing the number of TTIs between a grant and the corresponding UL message. The reduced UL timing delay may decrease the likelihood that the UE will wait for a subsequent transmit opportunity (TxOp) to transmit the UL message. In some cases, the reduced UL timing delay corresponds to a reduced hybrid automatic repeat request (HARM) processing delay. In some cases, a time difference (e.g., measured in TTIs) between a measurement reference TTI a corresponding channel state information (CSI) report may also be reduced.

Abstract: A base station is disclosed that includes two separated antenna arrays. In a TDD mode of operation, both arrays are used for either transmit or receive. In a sub-band full-duplex mode of operation, one array is used to transmit downlink symbols while the remaining array is used to receive uplink symbols.

Abstract: Methods, systems, and devices for wireless communications are described. A method for wireless communication may include receiving a single frequency networked composite reference signal (SFNed RS) at a first port of a user equipment (UE) and receiving a reference signal (RS) at a second port of the UE that is different than the first port of the UE. The method may also include performing channel estimation for at least one of the first port or the second port based at least in part on receiving the SFNed RS and the RS. A method for wireless communication may include transmitting a first portion of an SFNed RS from a first port of a first transmit/reception point to a UE and transmitting a downlink control information message to the UE that indicates at least one transmission configuration indicator state identifier that identifies the SFNed RS.

Abstract: Systems and methods in which one or more wireless communication stations implement duplex-mode remediation to facilitate the signal communication when an issue with respect to self-interference is identified are described. Duplex-mode remediation may be implemented for various communication scenarios, such as for random access phase communications, for communications having different priorities, etc.

Abstract: Methods, systems, and devices for wireless communication are described. A wireless device may identify an uplink/downlink (UL/DL) configuration that defines subframe configuration options for each subframe of a frame. For example, the UL/DL configuration may establish parameters for time division duplexing (TDD) operation between a base station and a user equipment (UE). The wireless device (e.g., the UE or base station) may determine a constraint for a subframe of the frame based on the UL/DL configuration and then determine an adaptive subframe configuration based on the constraint. The adaptive subframe configuration may include one or several downlink symbol periods and one or several uplink symbol periods.

Abstract: Methods, systems, and devices for wireless communication are described. A user equipment (UE) and a base station may use low latency communications to improve the throughput of a wireless link. To facilitate efficient low latency communication, the UE may send UE-initiated CSI reports in addition to periodic and base station-initiated reports. For example, the UE may, in various examples, send UE-initiated CSI reports using contention based spectrum, using a request-to-transmit, or using a CSI differential (i.e., an indicator of a change in channel conditions). The base station may schedule different UEs for uplink low latency communication by providing resources to each UE for CSI and scheduling requests (SRs) using coherent or non-coherent uplink transmissions. The CSI and SR may also be combined with uplink feedback.

Abstract: This disclosure provides systems, devices, apparatus and methods, including computer programs encoded on storage media, for channel measurement and reporting by a FD UE. A user equipment (UE) may be configured to transmit an uplink (UL) signal in a set of UL resources configured with a base station. The UE may be further configured to monitor a set of downlink (DL) resources configured with the base station, the set of DL resources being adjacent to or at least partially overlapping with the set of UL resources. The UE may be further configure to determine a channel quality associated with the set of DL resources based on the UL signal transmitted in the set of UL resources. The UE may be configured to then transmit, to the base station, information indicating channel state feedback (CSF) based on the determined channel quality.

Abstract: Aspects described herein relate to determining that a time division is for receiving a synchronization signal block (SSB) and for a random access occasion (RO) for transmitting a random access preamble in full duplex (FD) communications, and based on the determining, at least one of receiving the SSB or transmitting the random access preamble in the RO during the time division.

Abstract: Methods, systems, and devices for wireless communication are described. A base station may transmit an indication of first and second configurations for sounding reference signal (SRS) transmissions during first and second transmission time intervals (TTIs) having different durations. A user equipment (UE) may identify an SRS to be transmitted and determine a configuration for the SRS transmission based on the TTI duration and the received indication of the first and second configurations. The UE may then transmit the SRS based on the configuration. A base station may receive an SRS during a TTI and may determine a channel quality based at least in part on the SRS. Additionally, a device may identify data to transmit during a TTI, determine a number of resource elements available for transmission of the data during a TTI, and determine a transport block size (TBS) for the data transmission based on the available resource elements.

Abstract: Aspects described herein relate to determining whether full duplex (FD) communications are configured during resources for communicating one or more messages of a random access procedure, where the FD communications comprising uplink communications and downlink communications occurring in a same frequency band, and responsive to the determining whether the FD communications are configured during the resources, transmitting the one or more messages of the random access procedure using the resources.

Abstract: Methods, systems, and devices for wireless communications are described. The described techniques generally support downlink transmissions. For example, a user equipment (UE) may receive a resource configuration for reception of a downlink transmission within a repetition window, the resource configuration including an indicator of a repetition window size for the downlink transmission. The UE may monitor, according to the resource configuration, one or more transmission time intervals (TTIs) of the repetition window for reception of the downlink transmission. In some cases, the downlink transmission may be a grant-free downlink transmission. Here, the UE may attempt to decode the grant-free downlink transmission during the one or more TTIs based at least in part on the repetition window size.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may receive a resource allocation indicating a set of transmission tones comprising a set of data tones and a set of peak reduction tones (PRTs), wherein the resource allocation indicates locations for the set of data tones and locations for the set of PRTs within a particular bandwidth, wherein the locations for the set of PRTs are arranged relative to the locations for the set of data tones according to a PRT sequence, and wherein the PRT sequence comprises a plurality of contiguous PRTs arranged relative to a plurality of contiguous data tones or a pseudo-random pattern generated using a pseudo-random number generator; and transmit a data transmission using a waveform based at least in part on the resource allocation. Numerous other aspects are provided.

Abstract: This disclosure provides systems, devices, apparatus and methods, including computer programs encoded on storage media, for interference measurement and reporting by a UE. The interference measurement can be self-initiated by the UE or based on a request received from a BS. To measure the interference, the UE transmits a first signal in UL resources to a first BS concurrently with receiving a second signal in DL resources from one of the first BS or a second BS. The received second signal includes interference associated with the transmitted first signal. Based on the received second signal, the UE determines a level of the interference that is associated with the transmitted first signal. Information associated with the level of the interference is then transmitted to the first BS, such as an indication of a guard band that is to be incorporated between the UL resources and the DL resources.

Abstract: Aspects described herein relate to determining whether full duplex (FD) communications are configured during resources for communicating one or more messages of a random access procedure, where the FD communications comprising uplink communications and downlink communications occurring in a same frequency band, and responsive to the determining whether the FD communications are configured during the resources, transmitting the one or more messages of the random access procedure using the resources.

Abstract: Techniques provide for identifying uplink resources that are to be used for uplink transmissions using shortened transmission time intervals (sTTIs), such as low latency or high reliability transmissions. A reference signal (RS) configuration for a three-symbol sTTI, including locations of one or more RS symbols and one or more data symbols within the sTTI may be identified. The RS configuration, along with the allocation of uplink resources, may be provided to a user equipment (UE) which may transmit uplink communications using the allocated uplink resources.