Method of type II CSI reporting for multiple spatial layers

A non-transitory computer readable medium having instructions stored thereon that, when executed by one or more processors of a user equipment (UE), cause the UE to perform operations comprising:

• determining a precoding matrix indicator (PMI) for a set of precoding matrixes, wherein the PMI is determined based on a combination of mutually orthogonal digital Fourier transformation (DFT) spatial domain (SD) vectors with DFT-based frequency-domain (FD) compression, wherein the mutually orthogonal DFT SD vectors are selected as N subsets of a plurality of oversampled DFT SD vectors and a total number of elements of the N subsets is fixed, where N is a positive number greater than 1;
• and
• transmitting the PMI to a base station.

A user equipment (UE) comprising:

• a processor configured to determine a precoding matrix indicator (PMI) for a set of precoding matrixes, wherein the PMI is determined based on a combination of mutually orthogonal digital Fourier transformation (DFT) spatial domain (SD) vectors with DFT-based frequency-domain (FD) compression, wherein the mutually orthogonal DFT SD vectors are selected as N subsets of a plurality of oversampled DFT SD vectors and a total number of elements of the N subsets is fixed, where N is a positive number greater than 1;
• and
• a radio frequency integrated circuit, coupled to the processor, configured to transmit the PMI to a base station.