Abstract: Aspects present herein relate to methods and devices for wireless communication including an apparatus, e.g., a UE and/or a base station. The apparatus may encode a plurality of bits associated with QAM, the plurality of bits corresponding to a circular buffer associated with at least one RV, the plurality of bits including a plurality of systematic bits. The apparatus may also transfer the plurality of bits from the circular buffer associated with the at least one RV to a first buffer and a second buffer. Additionally, the apparatus may map the plurality of bits from the first buffer and the second buffer to a plurality of modulation symbols.

Abstract: An apparatus may be configured to transmit (or receive) an indication of a first DMRS, where the first DMRS is identified based on at least two of a non-linearity of a power amplifier of the first device, a modulation and coding scheme (MCS) used for a data transmission associated with the first DMRS, or a channel type of a channel associated with the first DMRS; transmit (or receive), for a second device (or from a first device), the first DMRS for channel estimation at the second device; and transmit (or receive) the data transmission associated with the first DMRS.

Abstract: Certain aspects of the present disclosure provide techniques for using a guard interval in a delay-Doppler domain. A method of wireless communication includes converting information in a delay-Doppler domain to a time-frequency domain, wherein the information includes data and at least one guard interval (GI); mapping the converted information to time and frequency resources of an orthogonal frequency domain multiplexing (OFDM) resource grid in the time-frequency domain; generating a time-domain waveform based on the OFDM resource grid, wherein the time-domain waveform includes one or more GIs; and outputting the time-domain waveform for transmission to a node.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a mobile station may receive, based at least in part on a time-frequency domain resource block that is characterized at least by a frequency span and a time duration, a wireless signal that comprises: a first modulated portion located in a first partition of the time-frequency domain resource block, the first modulated portion being based at least in part on an orthogonal time frequency space (OTFS) modulation scheme, and a second modulated portion located in a second partition of the time-frequency domain resource block, the second modulated portion being based at least in part on a second modulation scheme. The mobile station may recover a channel state information reference signal (CSI-RS) from the first modulated portion or the second modulated portion. Numerous other aspects are described.

Abstract: Certain aspects of the present disclosure provide techniques for delay-Doppler processing in orthogonal frequency domain multiplexing (OFDM). A method of wireless communication includes obtaining an indication of a first resource allocation associated with a first signal; obtaining the first signal in an OFDM resource grid based at least in part on the first resource allocation; and processing the first signal in a delay-Doppler domain.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive first control signaling identifying a demodulation reference signal (DMRS) pattern that may be uniformly distributed in a time domain and a frequency domain. The DMRS pattern may include a first set of resource elements for the DMRS, a second set of resource elements for guard tones adjacent to and greater in frequency than the first set of resource elements, and a third set of resource elements for guard tones adjacent to and lower in frequency than the first set of resource elements. The UE may receive second control signaling that schedules a data signal to be communicated between the UE and a network node in a set of time-frequency resources. The UE may communicate the data signal according to the second control signaling and the DMRS according to the DMRS pattern.

Abstract: Disclosed are techniques for wireless communication. In an aspect, a wireless device maps data, a unique word (UW) sequence, and a suppression signal to a set of reserved time-domain resources based on a time-domain resource mapping and reservation rule to produce DFT input data. DFT processing is performed on the DFT input data to produce IFFT input data. IFFT processing is performed on the IFFT input data to produce the GI-based waveform with a data part (e.g., non-zero part) and a tail part (e.g., zero tail part). The wireless device may further transmit the GI-based waveform.

Abstract: Methods, systems, and devices for wireless communication are described to support guard interval (GI) configurations for multiple links. For example, a user equipment (UE) may determine a first GI duration for a first transmission reception point (TRP) and a second GI duration for a second TRP, when the UE is operating in a multi-TRP mode. The UE may determine the GI durations based on a difference in timing between signal reception from the first and second TRPs and may transmit a signal to one or both of the TRPs to indicate the GI durations. Based on the indicated GI durations, the first and second TRPs may transmit signaling to the UE that includes or implements the corresponding GI duration for each TRP. For example, the signaling may include a GI appended at the end of each symbol period that has a GI duration corresponding to the respective TRP.

Abstract: Methods, systems, and devices for wireless communications are described. A transmitting device, such as a network entity, may transmit an indication (e.g., via control signaling) to a receiving device, such as a user equipment (UE), indicating that a secure downlink message is scheduled for transmission to the UE. The UE may transmit a sounding reference signal (SRS) to the network entity in response to the control signaling, and the network entity may determine a channel estimate and construct interference based on the channel estimate. The network entity may encode the secure downlink message according to an orthogonal time frequency space (OTFS) precoding scheme and may add the interference to the encoded secure downlink message over a slot duration. The network entity may transmit the encoded secure downlink message, including the added interference, to the UE. The UE may decode the encoded secure downlink message based on the OTFS precoding scheme.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) or a base station may generate a discrete Fourier transform (DFT) waveform from separate DFT inputs of data content, a guard interval (GI) sequence, and tail suppression samples. The UE or the base station may generate a first communication with the DFT waveform using an inverse fast Fourier transform (IFFT) operation. The first communication may include, in a time domain, a data signal corresponding to the data content and a GI-based tail signal that corresponds to the GI sequence and that is suppressed with a tail suppression signal based at least in part on the tail suppression samples. The UE or the base station may transmit the first communication. Numerous other aspects are described.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, an integrated access and backhaul (IAB) node may receive, from a first wireless device, an uplink communication using a first guard interval. The IAB may receive, from a second wireless device, a downlink communication using a second guard interval, a second length of the second guard interval being different from a first length of the first guard interval. The IAB may process the uplink communication and the downlink communication in a same fast Fourier transform window. Numerous other aspects are described.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first network node may apply an orthogonal time frequency space (OTFS) precoding to a plurality of tracking reference signal (TRS) resource samples allocated in a delay-Doppler domain to obtain a plurality of TRS symbols with the OTFS precoding. The first network node may transmit, to a second network node, a TRS in which the plurality of TRS symbols with the OTFS precoding have a uniform spacing in a time domain. Numerous other aspects are described.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may precode a sounding reference signal (SRS) transmission using a delay-Doppler precoder. The UE may transmit, after precoding the SRS transmission using the delay-Doppler precoder, the SRS transmission in an SRS symbol in a slot. Numerous other aspects are described.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive first configuration information indicating a first guard interval associated with sidelink communications. The UE may transmit, to a base station and another UE, a first sidelink communication using the first guard interval. The UE may transmit, to the base station and using a second guard interval having a second length that is different from a first length of the first guard interval, an uplink communication. Numerous other aspects are described.

Abstract: Methods, systems, and devices for wireless communications are described. A wireless device may generate a orthogonal time frequency space (OTFS) waveform for transmission to a second wireless device. Generation of an OTFS waveform may include mapping information samples to a delay-Doppler resource grid having a set of delay values and a set of Doppler values. A channel estimation block may occupy one or more rows of the delay-Doppler grid. When mapping information samples to the delay-Doppler grid, the transmitting device may first map information samples in the delay dimension (e.g., first map all of the symbols in one column of the delay-Doppler grid before mapping information samples into a second column). Such a mapping scheme may reduce the distance from any given information sample to the channel estimation block.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may precode a sounding reference signal (SRS) transmission using a delay-Doppler precoder. The UE may transmit, after precoding the SRS transmission using the delay-Doppler precoder, the SRS transmission in an SRS symbol in a slot. Numerous other aspects are described.

Abstract: Methods, systems, and devices for wireless communications are described. For example, a wireless device may support physical broadcast channel (PBCH) precoding in high-doppler scenarios. In some cases, a base station may generate a synchronization signal block (SSB) including synchronization signals and PBCH signaling. The base station may transmit, to a UE, the PBCH signaling in accordance with an orthogonal time frequency space (OTFS) precoding and the synchronization signals in accordance with a non-OTFS precoding. The UE may monitor for the SSB and receive the PBCH signaling in accordance with the OTFS precoding and the synchronization signals in accordance with a non-OTFS precoding. The UE may establish or modify a connection with the base station according to the PBCH signaling.

Abstract: Certain aspects of the present disclosure provide techniques for hybrid modulation and demodulation, which may include multiplexing and demultiplexing different waveform types. An example method includes receiving a time-domain waveform from a transmitting entity and converting the time-domain waveform to a frequency domain. The method also includes identifying a first set of time and frequency resources associated with converted first information and a second set of time and frequency resources associated with second information in time and frequency resources of an orthogonal frequency domain multiplexing (OFDM) resource grid in a time-frequency domain. The method further includes decoding the first set of time and frequency resources to generate first information from the converted first information. For certain aspects, the first information may be precoded with an orthogonal time frequency space (OTFS) modulation.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may precode a physical sidelink control channel (PSCCH) communication using a first delay-Doppler precoder. The UE may precode a physical sidelink shared channel (PSSCH) communication using one or more second delay-Doppler precoders. The UE may transmit the PSCCH communication and the PSSCH communication in a slot after precoding the PSCCH communication and the PSSCH communication. Numerous other aspects are described.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a synchronization signal block (SSB) transmitted using a single carrier quadrature amplitude modulation (SC-QAM) waveform, wherein the SSB has a uniform bandwidth allocation for each of a primary synchronization signal (PSS) included in the SSB, a secondary synchronization signal (SSS) included in the SSB, and physical broadcast channel (PBCH) data included in the SSB. The UE may perform initial channel access based at least in part on the SSB. Numerous other aspects are described.