This application discloses a communication method and a communications apparatus. The method includes: determining, by a first device, a phase tracking reference signal PTRS pattern, where the PTRS pattern includes one or more PTRS chunks, and each PTRS chunk includes one or more PTRS samples; and mapping, by the first device, a PTRS to one or more symbols, and sending the one or more symbols to a second device.

A channel measurement method and a communications apparatus, the method including generating, by a terminal device, first indication information, where the first indication information indicates one or more component features of a time-varying feature, and further indicates a weighting coefficient of each component feature of the one or more component features, and the one or more component features and the weighting coefficient of each component feature represent the time-varying feature of a channel, and sending, by the terminal device, the first indication information to a network device.

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.

A method for minimizing a time domain mean square error (MSE) of channel estimation (CE) includes estimating, by a processor, a power delay profile (PDP) from a time domain observation of reference signal (RS) channels; estimating, by the processor, a noise variance of the RS channels; and determining, by the processor, a first arrival path (FAP) value and a delay spread estimation (DSE) value based on the estimated PDP and the estimated noise variance for minimizing the MSE of CE.

Methods for determining variability in a state of a medium, include monitoring the medium and determining the variability in the state of the medium based on the processing of the response over time based on the response detected at the at least one receive element over time. Monitoring the medium can include generating a transmit signal, transmitting it into the medium using a transmit element, and receiving a signal from the medium at a receive element. The transmit and receive elements can be decoupled from one another. The transmit and receive elements can have differing geometry. The determined variability in the state of the medium can be used to provide notifications and/or take automated actions.

Aspects herein describe increasing density of reference signal transmissions in wireless communications. A plurality of reference signal configurations, each indicating resource elements for one or more antenna ports over which reference signals for the one or more antenna ports are scheduled for transmission, can be received. An association configuration indicating an association between at least two antenna ports as having similar channel characteristics can also be received. A plurality of reference signals can be received in the resource elements corresponding to the at least two antenna ports as indicated in the at least two of the plurality of reference signal configurations, which can be used to perform a channel measurement of the similar channel characteristics of channels of the at least two antenna ports over at least a portion of the plurality of reference signals.

Architectures and techniques are presented that improve or enhance a network planning procedure such as interactively planning suitable locations for transceiver sites that communicate with one another. Map data indicative of a 3D depiction of a physical space can be presented to a user interface device. Input indicative of a first transceiver site and a second transceiver site can be received. A Fresnel zone between the first transceiver site and the second transceiver site can be determined based on the map data. An interactive representation of the Fresnel zone can be presented to the user interface device.

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); and communicate the uplink transmission or the downlink transmission based at least in part on the request. Numerous other aspects are provided.

A method for minimizing a time domain mean square error (MSE) of channel estimation (CE) includes estimating, by a processor, a power delay profile (PDP) from a time domain observation of reference signal (RS) channels; estimating, by the processor, a noise variance of the RS channels; and determining, by the processor, a first arrival path (FAP) value and a delay spread estimation (DSE) value based on the estimated PDP and the estimated noise variance for minimizing the MSE of CE.

A radio receiver includes a channel estimator processing circuit including: a feature extractor configured to extract one or more features from a received signal, the features including a channel correlation estimated based on a reference signal in a current slot, the estimated channel correlation indicating a rate of change of a wireless channel over time; and a Doppler spread estimator configured to estimate a Doppler spread of the wireless channel by supplying the features to one or more Doppler shift predictors trained on training data across a training signal-to-noise ratio (SNR) range and across a training Doppler shift range, each Doppler shift predictor being trained on a portion of the training data corresponding to a different portion of the training data.