This disclosure describes systems, methods, and devices related to receiver diversity for Wi-Fi sensing. A device may identify first packets received from a second device during a time period, the first packets received using a first communication link between the device and the second device, and may identify second packets received from a third device during the time period, the second packets received using a second communication link between the device and the third device. The device may determine, based on the first packets, a first value indicative of a first amount of channel state variance associated with the first communication link during the time period. The device may determine, based on the second packets, a second value indicative of a second amount of channel state variance associated with the second communication link during the time period. The device may send the first value and the second value.

Embodiments are presented herein of apparatuses, systems, and methods for a wireless device to perform improved channel estimates for sensing applications such as ranging. The wireless device may determine noise characteristics, e.g., a spectrum of the variance of noise on a channel and may use the noise characteristics to estimate a response of an analog front end of the wireless device. The wireless device may correct a channel estimate based on the estimated response of the analog front end.

The invention relates to a mixer circuit, which includes a transconductance stage circuit, a switch stage circuit and a load stage circuit which are electrically connected in sequence. The transconductance stage circuit is used to access a radio frequency voltage signal and convert the radio frequency voltage signal into a radio frequency current signal The switch-level circuit is used to access the local oscillator signal and the radio frequency current signal, and the switch-level transistor is turned on by using the local oscillator signal; the load-level circuit is used to convert the intermediate frequency current signal into a voltage signal for output. In the present invention, the transconductance stage circuit adopts a transistor superposition technology structure, which improves the conversion gain of the mixer; at the same time, it uses a source degenerate inductance structure, which further improves the conversion gain and linearity of the circuit.

Facilitating sparsity adaptive feedback in the delay doppler domain in advanced networks (e.g., 4G, 5G, 6G, and beyond) is provided herein. Operations of a method can comprise determining, by a first device comprising a processor, a channel covariance matrix in a time-frequency domain based on a channel estimation associated with reference signals received from a second device. The method also can comprise decomposing, by the first device, the channel covariance matrix into a group of component matrices. Further, the method can comprise transforming, by the first device, respective matrices of the group of component matrices into respective covariance matrices in a delay doppler domain. The method also can comprise determining, by the first device, channel state information feedback in the delay doppler domain.

Disclosed is a signal source estimation method and apparatus performing the same, the signal source estimation method including acquiring first reception signals received by first receivers, among signals radiated from signal sources, selecting second receivers receiving reception signals to be used to estimate the signal sources, from among the first receivers based on the first reception signals, and detecting the number of signal sources based on second reception signals received by the second receivers.

Embodiments are presented herein of apparatuses, systems, and methods for a wireless device to perform improved channel estimates for sensing applications such as ranging. The wireless device may determine noise characteristics, e.g., a spectrum of the variance of noise on a channel and may use the noise characteristics to estimate a response of an analog front end of the wireless device. The wireless device may correct a channel estimate based on the estimated response of the analog front end.

Various embodiments disclosed herein provide for a reciprocity based channel state information acquisition scheme for frequency division duplex wireless communications systems. By converting channel state information from a traditional frequency-time domain to a Delay-Doppler domain, the channel state information feedback overhead can be reduced since the multi-path of radio propagation is reciprocal in terms of each ray and each cluster of antenna elements. Since the surrounding objects create the same multipath fading for both uplink and downlink transmissions, modeling the channel state information in the Delay-Doppler domain, and adjusting the sign of the Doppler value (negative/positive) can account for the multipath characteristics in both uplink and downlink.

Complex transfer functions indicating characteristics of propagation between transmission antenna elements and N reception antenna elements are calculated from reception signals received by the N reception antenna elements during a predetermined period. Components affected by vital activity are extracted from the calculated complex transfer functions. A correlation matrix is calculated from changed components affected by vital activity. A steering vector for regions divided from a target region is calculated. A living-body signal intensity vector is estimated by performing compressed sensing for an unknown value that is the living-body signal intensity vector using a correlation matrix vector and an extended steering vector. The number of components constituting the living-body signal intensity vector and having a value of at least a predetermined threshold is estimated to be the number of living bodies, and positions of regions corresponding to the components are estimated to be estimated positions of the living bodies.

Various examples are provided for coherence diversity. In one example, a method includes receiving a product signal transmitted over a plurality of subcarriers, the product signal including a product superposition of a first baseband signal and a second baseband signal; estimating equivalent channel responses for the plurality of subcarriers based upon the pilot symbol in the number of time slots of the plurality of subcarriers; and decoding the second encoded message based at least in part upon the first baseband signal and the equivalent channel responses. The first baseband signal can include a pilot symbol in a number of time slots of at least a portion of the plurality of subcarriers and a first encoded message in a remaining number of time slots of the plurality of subcarriers, and the second baseband signal can include a second encoded message.

A method for selecting at least one parameter for downlink data transmission with a mobile user equipment. The method is executable by a wireless communication base station having multiple antennas configured to communicate wirelessly with the mobile user equipment. The method receives an uplink probing signal from the mobile user equipment. The method determines a plurality of angles of arrival for a corresponding plurality of paths between the mobile user equipment and the multiple antennas. The method transmits a plurality of downlink probing signals directionally toward corresponding angles of arrival in the plurality of angles of arrival. Each downlink probing signal is a virtual antenna port with respect to the mobile user equipment. The method receives channel state information. The method composes at least one of a rank indicator (RI), precoding matrix indicator (PMI), or modulating and coding scheme (MCS) for downlink data transmission to the mobile user equipment.