an be reported as a subband component. The design as such follows the LTE block diagonal structure containing the same 2D DFT beam(s) to the two polarizations: where B is composed of L oversampled 2D DFT beams B = [bob, - 6.12 5G MIMO and Beamforming Operation For ranks 1 and 2, the value of L is configurable as L = 1 and L = 4. When L = 1, beam selection is wideband, whereas further subband beam selection is possible when L 4. The corresponding rank-1 W2 matrices have the form in the case L = 1 and W2= in the case of L=4, where eja is a QPSK polarization co-phasing coefficient, and li is a size-L selection vector. For L = 4, several beam patterns are supported, similar to LTE Class A (Figure 6.43). Several 1D/2D antenna ports layouts (N , N2) and oversampling factors (O1, O2) are supported as listed in Table 6.14. Type | Multi-Panel Codebook The multi-panel codebook is supported for ranks 1 to 4. The codebook construction is based on the single-panel design by utilizing a co-phasing between the single-panel precoders: normalized where - p = 1, - 1 are the panels, with g being the number of panels r=0,1 are the two polarizations - l=0,1, ...) R - 1 are the number of layers, with R being the rank is taken from the single-panel codebook with L = 1 Cp,r,l is the co-phasing for panels and polarizations Figure 6.43 Beam patterns for Type I codebook. Left: 2D antenna port layout, right: 1D antenna port layout. Table 6.14 Antenna power layouts and oversampling factors. Number of CSI-RS ports (N,N2) (O1, O2) (2,1) (4,-) (2,2), (4,1) (4,4), (4,-) (3,2), (6,1) (4,4), (4,-) (4,2), (8,1) (4,4), (4,-) (6,2), (4,3), (12,1) (4,4), (4,-) (8,2), (4,4), (16,1) (4,4), (4,-) 6 5G Physical Layer Table 6.15 Antenna power layouts and oversampling factors. Number of CSI-RS ports (Ng,N1,N2) (01,02) (2,2,1) (4,-) (2,2,2), (2,4,1), (4,2,1) (4,4), (4,-) (2,4,2), (4,4,2), (2,8,1), (4,4,1) (4,4), (4,-) The inter-panel co-phasing could be configured in wideband mode for 2 or 4 panels or in subband mode for 2 panels. In subband mode, a maximum 