Abstract: 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.

Abstract: A method of pre-compensating for transmitter in-phase (I) and quadrature (Q) mismatch (IQMM) may include sending a signal through an up-converter of a transmit path to provide an up-converted signal, determining the up-converted signal, determining one or more IQMM parameters for the transmit path based on the determined up-converted signal, and determining one or more pre-compensation parameters for the transmit path based on the one or more IQMM parameters for the transmit path. In some embodiments, the up-converted signal may be determined through a receive feedback path. In some embodiments, the up-converted signal may be determined through an envelope detector.

Abstract: An in-phase and quadrature mismatch compensator for a quadrature transmitter includes a delay element, a complex-valued filter and an adder. The delay element receives an input transmit signal and outputs a delayed transmit signal. The complex-valued filter receives the input transmit signal and outputs a selected part of a filtered output transmit signal. The adder adds the delayed transmit signal and the selected part of the filtered output transmit signal and outputs a pre-compensated transmit signal. In one embodiment, the selected part of the filtered output transmit signal includes the real part of the complex-valued output transmit signal. In another embodiment, the selected part of the filtered output transmit signal includes the imaginary part of the complex-valued output transmit signal. Two transmit real-valued compensators are also disclosed that combine the in-phase and quadrature signals before being filtered.

Abstract: Compressive sensing (CS) channel recovery using history measurements. Both current and history measurements for AoAs estimation, and only use current measurement for coefficient estimation. The dominant angle of arrival (AoA) is estimated using history and current measurements. In Approach 1, the dominant AoA is invariant and the coefficients are uncorrelated. In Approach 2, the dominant AoA is invariant and the coefficients are fully correlated. The remaining AoAs are estimated. The coefficients corresponding to each estimated dominant AoA are estimated. And the channel is recovered.

Abstract: A wireless communication device includes: a processing circuit configured to: receive, from an antenna array during a previous period, a first directional electromagnetic signal including beam sweeping reference symbols of a previous beam sweeping period; compute an estimated combined channel; estimate a dominant angle-of-arrival (AoA) of the first directional electromagnetic signal based on the estimated combined channel and a previous beamforming codebook including two or more beamforming vectors corresponding to different AoAs; construct an updated beamforming codebook based on the estimated dominant AoA and one or more remaining AoAs spaced apart from the estimated dominant AoA; receive, at the antenna array during a current period, a second directional electromagnetic signal including data symbols; determine a beamforming vector for data reception of the second directional electromagnetic signal based on the updated beamforming codebook; and detect the data symbols in the second directional electromagnet

Abstract: A method of compensating for IQ mismatch (IQMM) in a transceiver may include sending first and second signals from a transmit path through a loopback path, using a phase shifter to introduce a phase shift in at least one of the first and second signals, to obtain first and second signals received by a receive path, using the first and second signals received by the receive path to obtain joint estimates of transmit and receive IQMM, at least in part, by estimating the phase shift, and compensating for IQMM using the estimates of IQMM. Using the first and second signals received by the receive path to obtain estimates of the IQMM may include processing the first and second signals received by the receive path as a function of one or more frequency-dependent IQMM parameters.

Abstract: Low-complexity methods of calculating a precoding matrix for use in MIMO transmission. In some embodiments, a method of calculating a precoding matrix includes (i) calculating a first portion of a first singular value decomposition, based on a first portion of a channel matrix; (ii) calculating a second portion of a second singular value decomposition, based on a second portion of the channel matrix; (iii) calculating an intermediate matrix, based on: the first portion of the first singular value decomposition and the second portion of the second singular value decomposition; and (iv) calculating a matrix of approximate right singular vectors. The calculating of the matrix of approximate right singular vectors may include calculating a product of factors, the factors including a first factor based on the conjugate transpose of the intermediate matrix, a second factor based on a unitary matrix, and a third factor based on a diagonal matrix.

Abstract: A method of optimizing at least one IQMC parameter value for an IQMC includes: generating a set of tested IQMC candidate parameter values by performing an iterative method including selecting a first IQMC candidate parameter value for the at least one parameter of the IQMC; determining, using the first IQMC candidate parameter value, a performance metric value that comprises at least one of (i) an image rejection ratio (IRR) value, (ii) a signal-to-interference-plus-noise ratio (SINR) value, or (iii) a signal-to-image ratio (SImR) value; and determining a second IQMC candidate parameter value that is an update to the first IQMC candidate parameter value. The method of optimizing at least one IQMC parameter value for an IQMC further includes determining an IQMC candidate parameter value of the set of tested IQMC candidate parameter values that optimizes the performance metric.

Abstract: According to one general aspect, an apparatus may include a pre-transmission circuit configured to encode a data signal for communication. The apparatus may include a peak-to-average-power ratio (PAPR) controlling circuit configured to set a power level for a level-adjusted data signal. In some embodiments, the PAPR circuit may be configured to set the power level by employing a multi-loop, multi-phase technique, wherein an inner loop employs multiple phases to constrain the PAPR and reduce at least one power-related error condition, and wherein an outer loop updates the power level. The apparatus may include a transmitter circuit configured to transmit the level-adjusted data signal.

Abstract: A method of pre-compensating for transmitter in-phase (I) and quadrature (Q) mismatch (IQMM) may include sending a signal through an up-converter of a transmit path to provide an up-converted signal, determining the up-converted signal, determining one or more IQMM parameters for the transmit path based on the determined up-converted signal, and determining one or more pre-compensation parameters for the transmit path based on the one or more IQMM parameters for the transmit path. In some embodiments, the up-converted signal may be determined through a receive feedback path. In some embodiments, the up-converted signal may be determined through an envelope detector.

Abstract: An in-phase and quadrature mismatch compensator for a quadrature transmitter includes a delay element, a complex-valued filter and an adder. The delay element receives an input transmit signal and outputs a delayed transmit signal. The complex-valued filter receives the input transmit signal and outputs a selected part of a filtered output transmit signal. The adder adds the delayed transmit signal and the selected part of the filtered output transmit signal and outputs a pre-compensated transmit signal. In one embodiment, the selected part of the filtered output transmit signal includes the real part of the complex-valued output transmit signal. In another embodiment, the selected part of the filtered output transmit signal includes the imaginary part of the complex-valued output transmit signal. Two transmit real-valued compensators are also disclosed that combine the in-phase and quadrature signals before being filtered.

Abstract: A method and system analog beamforming for a single-connected antenna array is herein disclosed. A method includes estimating analog channels on a per-antenna basis, calculating explicitly an analog beamforming matrix based on the estimated analog channels, and performing analog beamforming based on the calculated analog beamforming matrix.

Abstract: A wireless communication device includes: a processing circuit configured to: receive, from an antenna array during a previous period, a first directional electromagnetic signal including beam sweeping reference symbols of a previous beam sweeping period; compute an estimated combined channel; estimate a dominant angle-of-arrival (AoA) of the first directional electromagnetic signal based on the estimated combined channel and a previous beamforming codebook including two or more beamforming vectors corresponding to different AoAs; construct an updated beamforming codebook based on the estimated dominant AoA and one or more remaining AoAs spaced apart from the estimated dominant AoA; receive, at the antenna array during a current period, a second directional electromagnetic signal including data symbols; determine a beamforming vector for data reception of the second directional electromagnetic signal based on the updated beamforming codebook; and detect the data symbols in the second directional electromagnet

Abstract: 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.

Abstract: An apparatus and method for optimizing a physical layer parameter is provided. According to one embodiment, an apparatus includes a first neural network configured to receive a transmission environment and a block error rate (BLER) and generate a value of a physical layer parameter; a second neural network configured to receive the transmission environment and the BLER and generate a signal to noise ratio (SNR) value; and a processor connected to the first neural network and the second neural network and configured to receive the transmission environment, the generated physical layer parameter, and the generated SNR, and to generate the BLER.

Abstract: Compressive sensing (CS) channel recovery using history measurements. Both current and history measurements for AoAs estimation, and only use current measurement for coefficient estimation. The dominant angle of arrival (AoA) is estimated using history and current measurements. In Approach 1, the dominant AoA is invariant and the coefficients are uncorrelated. In Approach 2, the dominant AoA is invariant and the coefficients are fully correlated. The remaining AoAs are estimated. The coefficients corresponding to each estimated dominant AoA are estimated. And the channel is recovered.

Abstract: A method of gain step calibration by a user equipment (UE) includes selecting, a l th antenna path having a gain GT for a transmitter (Tx) of the UE and a corresponding m th antenna path having a gain GR for a receiver (Rx) of the UE; determining, a first loopback signal power for the l th antenna path having the gain GT for the transmitter (Tx) of the UE and the corresponding m th antenna path having the gain GR for the receiver (Rx) of the UE; determining, a second loopback signal power for the l th antenna path having a gain G?T for the transmitter (Tx) and the corresponding m th antenna path having the gain GR for the receiver (Rx); and determining, a transmitter gain step of the UE based on the first loopback signal power and the second loopback signal power.

Abstract: A method for providing nonlinear self-interference cancellation of a wireless communication device includes: receiving digital samples of an interfering signal having a first sampling rate and a corrupted victim signal having a second sampling rate; generating a kernel vector based on the interfering signal, wherein the kernel vector has terms of nonlinear self-interference; estimating the nonlinear self-interference of the corrupted victim signal using the terms of the nonlinear self-interference; and providing an estimation of a desired signal by cancelling the nonlinear self-interference from the corrupted victim signal.

Abstract: A first antenna array includes antenna panels including: first antenna panels arranged on a first circle having a first radius, each of the first antenna panels including antenna elements: and second antenna panels arranged on a second circle having a second radius, each of the second antenna panels including antenna elements, the second circle being concentric with the first circle at a center point, the second antenna panels being arranged at a first angle around the center point with respect to the first antenna panels, the first radius, the second radius, and the first angle being computed in accordance with wireless transmission conditions including: a line-of-sight distance to a second antenna array including third antenna panels arranged on two or more circles; and a carrier frequency of a line-of-sight wireless transmission between the first antenna array and the second antenna array.

Abstract: A receiver circuit for separating a plurality of layers multiplexed in an orthogonal frequency domain multiplexed (OFDM) signal includes: a descrambling sub-circuit configured to descramble a plurality of signals received on non-adjacent subcarriers of the OFDM signal to generate a plurality of descrambled signals; an inverse fast Fourier transform sub-circuit configured to transform the descrambled signals from a frequency domain to a received signal including a plurality of samples in a time domain; and a layer separation sub-circuit configured to separate the layers multiplexed in the received signal by: defining a first time domain sampling window and a second time domain sampling window in accordance with a size of the inverse fast Fourier transform; extracting one or more first layers from the samples in the first time domain sampling window; and extracting one or more second layers from the samples in the second time domain sampling window.