A channel estimation system and method thereof is provided. By utilizing the nature of the millimeter-wave channel with sparse path, the channel estimation problem is transformed from estimating the entire channel matrix to estimating independent parameters of the millimeter-wave channel. These parameters are angle of arrival (AoA) and angle of departure (AoD), and complex gain of the channel paths.

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.

An apparatus for deriving a submatrix {tilde over (G)}.sup.1 is described. The apparatus for deriving a submatrix {tilde over (G)}.sup.1 is configured to select an N-elements-column and an N-elements-row of an NN-Matrix G or G.sup.1. The apparatus for deriving a submatrix {tilde over (G)}.sup.1 is configured to rearrange the selected column to the rightest column and the selected row to the lowest row of G or G.sup.1 so as to generate a NN-matrix G.sub.p or G.sub.p.sup.1. The apparatus for deriving a submatrix {tilde over (G)}.sup.1 is configured to calculate a submatrix {tilde over (G)}.sup.1 by ${\tilde{G}}^{-1}=A-\frac{\mathrm{AbcA}}{d^{-1}+c^T\mathrm{Ab}},$
wherein the parameters (N1)(N1)-submatrix A, b, d, c are obtained from the G.sub.p or the G.sub.p.sup.1; wherein $G_p=\left[\begin{array}{cc}\tilde{G}& b\\ c^T& d\end{array}\right],G_p^{-1}=[\begin{array}{cc}A& \tilde{b}\\ {\tilde{c}}^{}\end{array}$

Certain aspects of the present disclosure relate to methods and apparatus for performing one or more over the air calibration procedures for reciprocity based uplink MIMO transmissions, for example, in new radio (NR).

Aspects of the present disclosure describe receiving, from an access point, an indication of at least one of a beamforming method for beamforming a RS or a normalization method for normalizing power for beamforming the RS. A channel covariance matrix corresponding to interference over a plurality of antenna ports can be generated, as well as a RS beamforming matrix based at least in part on modifying the channel covariance matrix and on the normalization method. The RS can be generated based on the RS beamforming matrix and the beamforming method. The RS can be transmitted to the access point based on the RS beamforming matrix.

A channel estimation circuit (100) includes an input interface (110). The input interface (110) is configured to receive a plurality of pilot symbols from a communication channel. Furthermore, the channel estimation circuit (100) includes processing circuitry (120). The processing circuitry (120) is configured to generate a channel autocorrelation matrix and at least one channel cross-correlation vector. The generating of the channel autocorrelation matrix and the channel cross-correlation vector can be based on predetermined statistical information on the communication channel. Additionally, the processing circuitry (120) is configured to generate a subspace mapping for a subspace transformation based on the channel autocorrelation matrix. Additionally, the processing circuitry (120) is configured to generate a subspace transformed channel autocorrelation matrix, at least one subspace trans-formed channel cross-correlation vector, and a plurality of subspace transformed pilot symbols, by applying the subspace mapping to the channel autocorrelation matrix, the channel cross-correlation vector, and to the plurality of pilot symbols. Additionally, the processing circuitry (120) is configured to generate a plurality of subspace channel estimation filter coefficients based on the subspace transformed channel autocorrelation matrix and the sub-space transformed channel cross-correlation vector. Additionally, the processing circuitry (120) is configured to generate an estimate of at least one channel coefficient of the communication channel based on the subspace transformed pilot symbols and the subspace channel estimation filter coefficients. Furthermore, the channel estimation circuit (100) includes an output interface (150) configured to provide the estimate of the at least one chan-nel coefficient.

A method, performed in a network node, for channel characteristics handling for an antenna array in a communication system. The antenna array has a plurality of antenna elements. The method includes obtaining geometrical relationships between any pair of antenna elements in a spatial layout of the antenna array. All pairs of antenna elements are classified into sets based on the obtained geometrical relationships, wherein all pairs of antenna elements in a set have substantially equal geometrical relationship in the spatial layout. The method includes determining a representation of channel characteristics as P(), wherein argument is a vector of elements, each element relating to a magnitude and/or phase of covariance between the antenna elements in the set, and P is a mapping function based on the classifying. Antenna characteristics are processed based on the representation P().

For example, a first wireless communication device may be configured to cluster a plurality of channel estimation measurements into a plurality of clusters based on a clustering criterion, the plurality of channel estimation measurements corresponding to a respective plurality of Physical Protocol Data Units (PPDUs) received from a second wireless communication device over a wireless communication channel; and, based on clustering of the plurality of channel estimation measurements into the plurality of clusters, selectively provide a clustered channel estimation measurement to be processed for detection of changes in an environment of the wireless communication channel, by providing the clustered channel estimation measurement together with one or more other clustered channel estimation measurements of a same cluster of the clustered channel estimation measurement to be processed for the detection of the changes in the environment.

A channel estimation method in multiple-input multiple-output (MIMO) communication systems using a temporal correlation and an apparatus therefor are provided. The method includes quantizing a receive signal received via each of MIMO antennas using an analog-to-digital converter (ADC) and reflecting a temporal correlation in the quantized receive signal and estimating a channel for the receive signal, received via each of the MIMO antennas, based on the receive signal in which the temporal correlation is reflected.

An apparatus, comprising at least one processor and at least one memory storing instructions, the at least one memory and the instructions configured to, with the at least one processor, cause a receiver to perform a correlation processing of a first signal received by the receiver and/or of a second signal which can be derived from the first signal, and to at least temporarily modify an output signal of the correlation processing using at least one neural network, wherein a modified output signal may be obtained.