A method performed by a User Equipment, UE, the method comprising: - receiving from a network node, a radio signal via a Multiple Input Multiple Output, MIMO, channel, wherein the radio signal contains at least one DownLink, DL, reference signal according to a DL reference signal configuration; - estimating said MIMO channel based on said received at least one DL reference signal for configured resource blocks; - calculating a precoding matrix for a number of antenna ports of the network node and configured subbands; the precoding matrix being based on a first codebook and on a second codebook and a set of combination coefficients for complex scaling/combining one or more of vectors selected from the first codebook and the second codebook, wherein the first codebook contains one or more transmit-side spatial beam components/vectors of the precoding matrix and the second codebook contains one or more delay components/vectors of the precoding matrix; - receiving from said network node a higher layer configuration comprising indicating a subset of beam vectors from the first codebook and a maximum allowable average amplitude value per beam vector for restricting the average amplitude, or power, of the combining coefficients associated with the beam vector; and - reporting, to the network node, a Channel State Information, CSI, feedback and/or a Precoder matrix Indicator, PMI and/or a PMI/Rank Indicator, PMI/RI, used to indicate the precoding matrix for the configured antenna ports and subbands, wherein the report contains a bitmap for indicating at least selected delay vectors and spatial beam vectors associated with the non-zero combining coefficients of said set of combination coefficients. - receiving from a network node, a radio signal via a Multiple Input Multiple Output, MIMO, channel, wherein the radio signal contains at least one DownLink, DL, reference signal according to a DL reference signal configuration; - estimating said MIMO channel based on said received at least one DL reference signal for configured resource blocks; - calculating a precoding matrix for a number of antenna ports of the network node and configured subbands; the precoding matrix being based on a first codebook and on a second codebook and a set of combination coefficients for complex scaling/combining one or more of vectors selected from the first codebook and the second codebook, wherein the first codebook contains one or more transmit-side spatial beam components/vectors of the precoding matrix and the second codebook contains one or more delay components/vectors of the precoding matrix; - receiving from said network node a higher layer configuration comprising indicating a subset of beam vectors from the first codebook and a maximum allowable average amplitude value per beam vector for restricting the average amplitude, or power, of the combining coefficients associated with the beam vector; and - reporting, to the network node, a Channel State Information, CSI, feedback and/or a Precoder matrix Indicator, PMI and/or a PMI/Rank Indicator, PMI/RI, used to indicate the precoding matrix for the configured antenna ports and subbands, wherein the report contains a bitmap for indicating at least selected delay vectors and spatial beam vectors associated with the non-zero combining coefficients of said set of combination coefficients.