Abstract: Disclosed are techniques related to wireless communication system in which multi-level encoded modulation (MLCM) is applied to non-coherent communication. In the proposed techniques, a small fraction of differential phase rotations or bits participating in differential symbol coding are protected with strong codes while other complementary differential phase rotations or bits are protected with weaker codes. Compared to conventional non-coherent communication techniques in which a uniform protection is applied to any fraction of differential phase rotation or any bit of a differential symbol, the proposed MLCM approach enables more spectrally efficient scheme.

Abstract: The present disclosure involves determining base station (BS) beams for communicating between a UE and the BS. The BS may use sensor data or beam management reporting history to assist with determining one or more appropriate beams. The sensor data may include camera images, radar data, or lidar data, and be used to model the cell environment served by the BS. The BS may obtain reporting data from multiple UEs over time indicating the quality of beams received by the UEs at various locations in the cell environment and model the cell environment based on the reporting data. The BS may associate beams with possible UE locations within the cell environment and use the associations to determine beams for communicating with a UE after determining the UE's location.

Abstract: This disclosure provides systems, devices, apparatus and methods, including computer programs encoded on storage media, for a DPD training procedure. A base station may transmit, for a plurality of iterations, a signal to at least one UE through a plurality of transmit chains and with application of DPD. The signal transmitted for each iteration may be transmitted with a BW that extends over a plurality of subcarriers and includes pilots extending over a BW subset that increases in subcarrier size for each iteration. The base station may receive, for each iteration, feedback from the at least one UE based on the transmitted signal and apply DPD to each of the plurality of transmit chains based on the feedback. Accordingly, the base station may transmit to one or more UEs through the plurality of transmit chains and with application of the DPD pilot signals that extend over the entire BW.

Abstract: A method of wireless communications by a user equipment (UE) includes transmitting a wakeup message to awaken a base station from a sleep mode. The method also includes communicating with the base station after the base station awakens. A method of wireless communications by a base station includes entering a sleep mode when no user equipments (UEs) are connected to the base station. The method also includes receiving a signal from a UE to awaken from the sleep mode.

Abstract: Methods, systems, and devices for wireless communications are described that provide for adjustment of a frequency offset based on switching between uplink/downlink (UL/DL) transmission/reception beam pairs between a UE and a base station. A connection may be established via a first UL/DL transmission/reception beam pair and a frequency tracking loop may be established and maintained to correct for frequency error (e.g., due to Doppler shift) of received transmissions at a receiving device. In cases where a beam switch is performed, and the UE and base station switch from the first UL/DL transmission/reception beam pair to a second UL/DL transmission/reception beam pair, and a frequency offset difference between the first and second UL/DL transmission/reception beam pairs may be applied to the frequency tracking loop. The frequency offset difference may be obtained from a table of frequency offset measurements of multiple UL/DL beam pairs using associated reference signal transmissions.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit an indication that the UE supports communications having a first transport block applied to demodulation reference signals (DMRSs) and a second transport block applied to data symbols of a data channel. The UE may transmit an uplink communication or receiving a downlink communication having the first transport block applied to the DMRSs and the second transport block applied to the data symbols of the data channel. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communications are described. One method may include a user equipment (UE) receiving, in a first transmission time interval, a code block group including a set of code blocks associated with a set of codewords, each codeword being associated with one of a set of decoding levels introduced in communication scheme that uses multi-level coded modulation and multi-level sequential decoding. The UE may determine that a decoding procedure is unsuccessful, and transmit a feedback message including a first indicator that the decoding procedure was unsuccessful and a second indicator of a lowest decoding level for which the decoding procedure was unsuccessful. The UE may then receive, from the base station in a second transmission time interval, a retransmission of code blocks of the lowest failed decoding level coupled to a new data transmission for code blocks associated with all other decoding levels.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a base station may synchronize a beam switch of the base station with transmission of a reference signal for channel state feedback, and schedule a channel state feedback report to be transmitted after the transmission of the reference signal for channel state feedback. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communications are described. A base station may transmit, to a user equipment (UE), a first demodulation reference signal for each of one or more sub-bands and configured in accordance with a first one or more demodulation reference signal configurations. The UE may select a second demodulation reference signal configuration from a respective set of second demodulation reference signal configurations for each of the one or more sub-bands and may transmit an indication of the second demodulation reference signal configuration for each of the one or more sub-bands. The base station may receive the indication and may transmit, to the UE, a second demodulation reference signal for each of the one or more sub-bands and configured in accordance with the second demodulation reference signal configuration for each of the one or more sub-bands.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may transmit an indication of a capability of the UE to communicate one or more of uplink transmissions or downlink transmissions having amplitude-modulated phase tracking reference signals on at least a first layer of a multilayered communication link that includes the first layer and a second layer; and communicate an uplink transmission or a downlink transmission based at least in part on the indication. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communications are described. In some systems, a user equipment (UE) may determine a set of groups of layers relating to a set of transport blocks (TBs) or a set of code division multiplexing (CDM) groups. The UE may group the layers such that the layers in each group have a minimal difference in signal-to-interference-plus-noise ratio (SINR) between the layers. The UE may select a different demodulation reference signal (DMRS) configuration for each of the set of groups of layers based on maximizing a communication efficiency metric for each group of layers. The UE may transmit an indication of the selected DMRS configurations for each group of layers to a base station via a field in a report. The base station may accordingly determine a DMRS configuration for each group of layers based on the DMRS configurations indicated by the UE.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may transmit a request, for an uplink transmission or a downlink transmission, for amplitude modulated phase tracking reference signals; and communicate the uplink transmission or the downlink transmission based at least in part on the request. Numerous other aspects are provided.

Abstract: Various aspects of the present disclosure generally relate to wireless communication, reference signal configuration aspects, and dynamic and synchronous configuration signaling. In some aspects, a user equipment (UE) may transmit, to a base station (BS), an indication of a UE capability to support a reference signal configuration group of a plurality of reference signal configuration groups. The UE may receive, from the BS, an indication of a reference signal configuration from the reference signal configuration group. The indication if the reference signal configuration may be provided by the BS to dynamically configure a reference signal and can be provided by means of medium access control control element (MAC-CE) based activation or by means of activation of a subset of reference signal configurations with a complementary downlink control information (DCI) based selection of one of the activated reference signal configurations. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communications are described. A base station may transmit repetitions of a tracking reference signal to a user equipment (UE). The UE may determine a Doppler frequency for the downlink channel by measuring the repetitions of the tracking reference signal. The UE may transmit an indication of the downlink Doppler frequency to the base station. The base station may determine the uplink Doppler frequency based on the downlink Doppler frequency. The base station may use the uplink Doppler frequency to select an uplink demodulation reference signal (DMRS) configuration for the UE.

Abstract: A transmitting device may select frequency domain resources for an alert transmission based on a severity level of the alert transmission. The transmitting device may determine a severity level of an alert transmission to be transmitted on one or more available channels. The transmitting device may determine a presence of one or more systems configured to transmit on one or more neighbor channels of the one or more available channels. The transmitting device may select, for the alert transmission, frequency domain resources within the one or more available channels based on the presence of the one or more systems and the severity level. The frequency domain resources for a highest severity level transmission are spaced further apart from the one or more neighbor channels in the frequency domain than resources for a lower severity level transmission. The transmitting device may transmit the alert transmission on the frequency domain resources.

Abstract: Methods, systems, and devices for wireless communications are described. A base station may determine the subcarrier spacing and carrier frequency used by a user equipment (UE) for communicating with the base station. The base station may select a sounding reference signal (SRS) configuration for the UE that is based on the subcarrier spacing and carrier frequency used by the UE. The SRS configuration may define the temporal spacing between repetitions of the SRS. The base station may indicate the SRS configuration to the UE so that the UE transmits repetitions of the SRS according to the SRS configuration. The base station may measure the SRS repetitions from the UE to determine the Doppler frequency for the uplink channel. The base station may use the uplink Doppler frequency to select a demodulation reference signal (DMRS) configuration for the UE.

Abstract: Methods, systems, and devices for wireless communications are described. A link quality characteristic may be determined for a channel having a set of channel characteristics. The determined link quality characteristic may be used to estimate the equivalent link quality characteristic for different demodulation reference signal configurations given the side information of the set of channel characteristics. A mapping defined per set of channel characteristics may be used to determine the estimated equivalent link quality characteristics from the determined link quality characteristic. A demodulation reference signal configuration may be selected based on the estimated equivalent link quality characteristics and a communication efficiency metric. The demodulation reference signal configuration that maximizes the communication efficiency metric may be selected. The selected demodulation reference signal may be signaled to a device that transmits demodulation reference signals.

Abstract: A phase tracking reference signal (PTRS) may be enhanced to carry data encoded with a relative low modulation and coding scheme (MCS). A receive device may receiving a data channel, the data channel including a transport block encoded using a first MCS. The receiving device may receiving a PTRS interleaved with the data channel. The PTRS is encoded with the second MCS that is lower than the first MCS. The receiving device may decode the PTRS to determine PTRS data. The receiving device may track phase noise using the PTRS data as a transmitted sequence of the PTRS. The receiving device may decode the transport block for the data channel based on the first MCS and the tracked phase noise.

Abstract: In one aspect, a method of wireless communication includes generating, by a user equipment (UE), a delta precoding value for a precoding matrix update, the delta precoding value relative to a previous precoding matrix. The method also includes generating, by the UE, a delta power loading value for the precoding matrix update, the delta power loading value relative to the previous precoding matrix. The method further includes transmitting, by the UE, a transmission indicating the delta precoding value and the delta power loading value. Other aspects and features are also claimed and described.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may transmit a request, for an uplink transmission or a downlink transmission, for data aided phase tracking reference signals (PT-RSs) on multiple layers of a communication link; and communicate the uplink transmission or the downlink transmission based at least in part on the request. Numerous other aspects are provided.