For Type-II codebook compression, methods, apparatus, and systems are disclosed. One apparatus includes a transceiver that receives a reference signal and a processor that identifies a set of taps over a layer based on the reference signal, where the set of taps are selected from a set of Nsb indices, the value Nsb representing a number of sub-bands. The processor generates a combinatorial codeword representing the set of taps. The processor reports the combinatorial codeword for the set of taps as part of a CSI feedback report.

Certain aspects of the present disclosure provide techniques for reporting beam-strength related Type-II channel state information (CSI) coefficient feedback.

The embodiments herein relate to method performed by a radio network node, a network node, a method performed by a UE and a UE for reducing feedback overhead. The method performed by the UE comprises at least: decomposing each entry corresponding to a (i, j)-th combining coefficient of a precoder matrix into at least two coefficients; quantizing, separately, each of said at least two coefficients with a least one bit, and reporting information related to at least one phase value or at least one amplitude value or at least one phase value and an amplitude value of said quantized coefficient.

This application discloses a precoding matrix index (PMI) reporting method, and related communications apparatus and medium. The method includes: determining an rank indicator (RI) and a PMI, where the PMI is used to determine R precoding matrices W.sub.1, . . . , W.sub.R. An r.sup.th precoding matrix W.sub.r in the R precoding matrices satisfies W.sub.r=W.sub.1×W.sub.2,r, where an l.sup.th row of W.sub.2,r is obtained by performing DFT transform on an l.sup.th row of a matrix V.sub.2,r, and R is indicated by the RI. The PMI includes first indication information and second indication information. The first indication information includes location index information. The location index information is used to indicate K.sub.m,r element locations t.sub.r,m,1, . . . , ∈{1, . . . , T} on an m.sup.th row of V.sub.2,r. The second indication information is used to indicate K.sub.m,r complex coefficients at the element locations t.sub.r,m,1, . . . , on the m.sup.th row of V.sub.2,r. V.sub.2,r is determined based on the K.sub.m,r element locations and the K.sub.m,r complex coefficients.

Provided are a method and apparatus for transmitting and receiving channel state information, a communication node, and a storage medium. A CSI matrix H is decomposed to obtain a vector group, where the vector group comprises at least two vector matrices, element information of at least one vector matrix in the vector group is quantized, and the quantized element information is transmitted.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a base station may select a precoding matrix of orthogonal beams. The base station may precode a channel state information reference signal (CSI-RS) transmitted to a user equipment (UE) using the precoding matrix of orthogonal beams. The base station may receive, from the UE, one or more reports that indicate one or more beam indices selected from beam indices associated with the precoding matrix of orthogonal beams. Numerous other aspects are provided.

An approach is described that includes receiving a CSI report, where the CSI report includes a channel quality indicator (CQI), a rank indicator (RI), and a precoding matrix indicator (PMI). The approach further includes constructing a precoding matrix based on a linear combination of a plurality of mutually orthogonal digital Fourier transformation (DFT) spatial beams, and determining a number of bits for the PMI of the precoding matrix. The approach also includes determining a space frequency matrix based, at least in part, on the number of bits for the PMI and the precoding matrix, and compressing the space frequency matrix. Finally, the approach includes determining a compressed PMI based, at least in part, on the space frequency matrix.

An approach is described that includes receiving a CSI report, where the CSI report includes a channel quality indicator (CQI), a rank indicator (RI), and a precoding matrix indicator (PMI). The approach further includes constructing a precoding matrix based on a linear combination of a plurality of mutually orthogonal digital Fourier transformation (DFT) spatial beams, and determining a number of bits for the PMI of the precoding matrix. The approach also includes determining a space frequency matrix based, at least in part, on the number of bits for the PMI and the precoding matrix, and compressing the space frequency matrix. Finally, the approach includes determining a compressed PMI based, at least in part, on the space frequency matrix.

A method for transmitting channel state information performed by a User Equipment (UE) may include receiving, from a base station, a bitmap for configuring codebook subset restriction (CSR) and reporting, to the base station, Channel State Information (CSI), when a number of antenna ports is configured as 16 or more and a number of layers associated with a rank indicator (RI) in the CSI is 3 or 4, a unit of multiple bits in a bitmap for configuring the CSR is associated with each precoder, and a reporting of precoding matrix indicator (PMI) corresponding to the precoder associated with the multiple bits is restricted in the CSI, when the CSR is indicated in any one of the multiple bits, and each bit in the bitmap for configuring the CSR is associated with each precoder.

The invention relates to a method for decoding an RF signal bearing a sequence of transmitted symbols modulated by CPM. The method comprises, at the receiver (1): Estimating model parameters {h, ω, Φ.sub.0} among which h characterizes a modulation index, ω characterizes a carrier frequency offset and Φ.sub.0 characterizes an initial phase offset, and Detecting received symbols corresponding to said transmitted symbols of the sequence, wherein, at time nT where T is a symbol duration, the parameters {h, ω, Φ.sub.0} are estimated by solving a system of three linear equations whose: a. three unknowns {ĥ.sup.(n), {circumflex over (ω)}.sup.(n), {circumflex over (Φ)}.sub.0.sup.(n)}, are respectively function of said model parameters {h, ω, Φ.sub.0}, and b. coefficients {B.sup.(n), C.sup.(n), D.sup.(n), F.sup.(n), G.sup.(n), H.sup.(n), v.sub.1.sup.(n), v.sub.2.sup.(n), v.sub.3.sup.(n)} are computed in a recursive way in function of: iii. a sequence of symbols {â.sub.n} corresponding to the sequence of transmitted symbols up to time nT, and iv. measured phases {Ψ.sub.k} of samples {y.sub.k} of the RF signal received from time (n−1)T to time nT.