Abstract: A method of motion compensation for a Doppler radar system includes receiving, for each transmitted pulse of a set of transmitted pulses, a respective set of echo signals returned from a plurality of distance ranges, performing Doppler Fourier transforms on the sets of echo signals for the set of transmitted pulses to generate outputs that include detected signals in a plurality of velocity bins, and applying a respective pre-determined compensation phase vector to the detected signals in each velocity bin of the plurality of velocity bins. The respective pre-determined compensation phase vector applied to the detected signals in each velocity bin includes at least one of a first component proportional to a velocity of the velocity bin or a second component for compensating a phase compensation error associated with Doppler velocity aliasing.

Abstract: Various aspects of the present disclosure generally relate to media systems. In some aspects, a media device may monitor, using a radio frequency (RF) sensor, an environment of the media device; determine, from a received RF signal obtained by the RF sensor, a user attribute of a user within the environment; and control an audio system, associated with the media device, to direct an audio beam toward or away from the user. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communication are described. Generally, the described techniques provide for efficiently reporting channel state feedback for a set of subbands. As an example, a user equipment (UE) may receive a set of reference signals on the set of subbands and determine a respective channel quality indicator (CQI) index for each of the set of subbands based on the reference signals. The UE may then transmit indications of CQI indices for different subbands of the set using variable length indications, such as indications that include different numbers of bits. Since, in some examples, a small length or number of bits may be allocated for reporting CQI indices with a high probability of being reported, overhead in a wireless communications system may be reduced.

Abstract: Disclosed are techniques for liveliness detection. In an aspect, a radar sensor of an electronic device transmits a radar frame comprising a plurality of bursts, each burst comprising a plurality of radar pulses, and receives a plurality of reflected radar pulses. The electronic device generates a radar image representing azimuth, elevation, range, and slow time measurements for the radar frame based on the plurality of reflected pulses, applies a Doppler FFT to the radar image to convert the radar image to represent azimuth, elevation, range, and velocity measurements for the radar frame, identifies at least one area of motion in the radar image based on velocity bins of the radar image, and detects a target dynamic object based on a CFAR detection applied over the range and azimuth measurements and a SNR threshold of the received plurality of reflected pulses associated with the at least one area of motion.

Abstract: Apparatus and methods are disclosed for determining, at a radar device, range and Doppler velocity based on reduced Doppler-induced radar range sidelobes, including generating code sequence pairs such that a sum of autocorrelations of each code sequence pair has substantially no sidelobes, transmitting a plurality of pulses in an emitted burst, where each pulse of the emitted burst comprises a code sequence pair different from at least one other pulse of the burst such that the autocorrelation sum of the code sequence pairs of the two different pulses has sidelobes, receiving pulses in a reflected burst, each pulse a reflected copy of a corresponding pulse of the emitted burst, generating an autocorrelation sum for each reflected pulse with its corresponding emitted pulse, and determining range and Doppler velocity based on autocorrelation sums, where the sidelobes autocorrelation sums combine incoherently at reduced power.

Abstract: A transmitter may be configured to generate a reference signal having a non-constant envelope for nonlinearity estimation by a receiver. The transmitter may transmit the reference signal. A receiver may be configured to receive, from the transmitter, the reference signal having the non-constant envelope. The receiver may estimate at least one nonlinearity characteristic based on the reference signal having the non-constant envelope. The receiver may transmit feedback based on the at least one nonlinearity characteristic and/or perform at least one digital post distortion (DPoD) operation based on the at least one nonlinearity characteristic.

Abstract: Techniques provided herein are directed toward enabling short-range proximity detection using radar sensors by reducing or eliminating OTA leakage. Embodiments generally include performing spatial cancellation by using a plurality of transmit/receive pairs of antenna elements to implement analog and/or digital leakage cancellation on the transmit and/or receive side. According to some embodiments null space projection cancellation, OTA leakage tracking, or adaptive minimum variance distortionless response (MVDR) beamforming may be performed to help preserve of the OTA leakage cancellation efficacy over time.

Abstract: Methods, systems, and devices for wireless communication are described. Generally, the described techniques provide for efficiently reporting channel state feedback for a set of subbands. As an example, a user equipment (UE) may receive a set of reference signals on the set of subbands and determine a respective channel quality indicator (CQI) index for each of the set of subbands based on the reference signals. The UE may then transmit indications of CQI indices for different subbands of the set using variable length indications, such as indications that include different numbers of bits. Since, in some examples, a small length or number of bits may be allocated for reporting CQI indices with a high probability of being reported, overhead in a wireless communications system may be reduced.

Abstract: Techniques for performing gesture recognition with an electronic device are disclosed where the electronic device has a wireless communications capability using beamforming techniques and includes a plurality of millimeter wave antenna modules, each antenna module including at least one transmit antenna and at least one receive antenna, the antennas being operable in one or more frequency ranges greater than 20 GHz. Performing gesture recognition includes: simultaneous operation of the at least one transmit antenna and the at least one receive antenna so as to provide a radar capability; and detecting a presence and motion of a reflective object by analyzing magnitude and phase of signals received by the at least one receive antenna and resulting from reflection of signals transmitted by the transmit antenna and reflected by the reflective object.

Abstract: Disclosed are techniques for liveliness detection. In an aspect, a radar sensor of an electronic device transmits a radar frame comprising a plurality of bursts, each burst comprising a plurality of radar pulses, and receives a plurality of reflected radar pulses. The electronic device generates a radar image representing azimuth, elevation, range, and slow time measurements for the radar frame based on the plurality of reflected pulses, applies a Doppler FFT to the radar image to convert the radar image to represent azimuth, elevation, range, and velocity measurements for the radar frame, identifies at least one area of motion in the radar image based on velocity bins of the radar image, and detects a target dynamic object based on a CFAR detection applied over the range and azimuth measurements and a SNR threshold of the received plurality of reflected pulses associated with the at least one area of motion.

Abstract: A transmitter may be configured to generate a reference signal having a non-constant envelope for nonlinearity estimation by a receiver. The transmitter may transmit the reference signal. A receiver may be configured to receive, from the transmitter, the reference signal having the non-constant envelope. The receiver may estimate at least one nonlinearity characteristic based on the reference signal having the non-constant envelope. The receiver may transmit feedback based on the at least one nonlinearity characteristic and/or perform at least one digital post distortion (DPoD) operation based on the at least one nonlinearity characteristic.

Abstract: Techniques provided herein are directed toward enabling short-range proximity detection using radar sensors by reducing or eliminating OTA leakage. Embodiments generally include performing spatial cancellation by using a plurality of transmit/receive pairs of antenna elements to implement analog and/or digital leakage cancellation on the transmit and/or receive side. According to some embodiments null space projection cancellation, OTA leakage tracking, or adaptive minimum variance distortionless response (MVDR) beamforming may be performed to help preserve of the OTA leakage cancellation efficacy over time.

Abstract: A transmitter may be configured to generate a reference signal having a non-constant envelope for nonlinearity estimation by a receiver. The transmitter may transmit the reference signal. A receiver may be configured to receive, from the transmitter, the reference signal having the non-constant envelope. The receiver may estimate at least one nonlinearity characteristic based on the reference signal having the non-constant envelope. The receiver may transmit feedback based on the at least one nonlinearity characteristic and/or perform at least one digital post distortion (DPoD) operation based on the at least one nonlinearity characteristic.

Abstract: Space-time-frequency multiplexing (STFM) schemes for radio frequency (RF) scanning are disclosed in which complementary pairs of sequences (or “Golay pairs”) are transmitted at different times using multiple frequencies. The transmission and reception of the sequences can occur over multiple transmit (Tx) and/or receive (Rx) radio sectors to scan an entire area for range, azimuth, elevation, and (optionally) velocity of objects therein.

Abstract: In certain aspects of the present disclosure, a method for wireless communication comprises predistorting a first signal based on a set of coefficients to generate a first predistorted signal, outputting the first predistorted signal for a first transmission to a receiving device, and receiving a first feedback signal from the receiving device, wherein the first feedback signal provides feedback of a first receive signal at the receiving device corresponding to the first transmission. The method also comprises determining whether to store the set of coefficients in a memory based on the received first feedback signal, and storing the set of coefficients in the memory based on the determination.

Abstract: A transmitter may be configured to generate a reference signal having a non-constant envelope for nonlinearity estimation by a receiver. The transmitter may transmit the reference signal. A receiver may be configured to receive, from the transmitter, the reference signal having the non-constant envelope. The receiver may estimate at least one nonlinearity characteristic based on the reference signal having the non-constant envelope. The receiver may transmit feedback based on the at least one nonlinearity characteristic and/or perform at least one digital post distortion (DPoD) operation based on the at least one nonlinearity characteristic.

Abstract: In certain aspects of the present disclosure, a method for wireless communication comprises predistorting a first signal based on a set of coefficients to generate a first predistorted signal, outputting the first predistored signal for a first transmission to a receiving device, and receiving a first feedback signal from the receiving device, wherein the first feedback signal provides feedback of a first receive signal at the receiving device corresponding to the first transmission. The method also comprises determining whether to store the set of coefficients in a memory based on the received first feedback signal, and storing the set of coefficients in the memory based on the determination.

Abstract: A transceiver in a wireless device supporting carrier aggregation may include a correction module to generate a correction signal to attenuate intermodulation distortion associated with a first transmitted communication signal. In one embodiment, the correction signal may be added to the first transmitted communication signal (a victim signal) to reduce the intermodulation distortion caused by a second transmitted communication signal (an aggressor signal). The correction signal may be generated based on the aggressor signal. In another embodiment, the correction signal may equalize or pre-distort the first transmitted communication signal.

Abstract: A transceiver in a wireless device supporting carrier aggregation may include a correction module to generate a correction signal to attenuate intermodulation distortion associated with a first transmitted communication signal. In one embodiment, the correction signal may be added to the first transmitted communication signal (a victim signal) to reduce the intermodulation distortion caused by a second transmitted communication signal (an aggressor signal). The correction signal may be generated based on the aggressor signal. In another embodiment, the correction signal may equalize or pre-distort the first transmitted communication signal.