Method and apparatus for high-resolution CSI reporting in advanced wireless communication systems

A base station (BS), the BS comprising:

• a processor;
• and
• a transceiver configured to
• transmit, to a user equipment (UE), configuration information including information for a channel state information (CSI) report, the configuration information indicating a codebook type, wherein an intermediate basis set including N′ basis vectors common to a plurality of layers is based on a full basis set including N basis vectors, wherein a basis subset including Ml basis vectors each specific to a layer l of the plurality of layers is based on the intermediate basis set, and
• receive, from the UE, the CSI report including a pre-coding matric indicator (PMI) regarding the basis vectors included in the intermediate basis set and the Ml basis vectors included in the basis subset, from the UE,
• wherein N, N′, and Ml are positive integers, N′<N, Ml<N′, and l is a value corresponding to a number of the one or more layers.

A method for operating a user equipment (UE), the method comprising:

• receiving configuration information including information for a channel state information (CSI) report, the configuration information indicating a codebook type;
• identifying an intermediate basis set including N′ basis vectors common to a plurality of layers, based on a full basis set including N basis vectors;
• identifying a basis subset including Ml basis vectors each specific to a layer l of the plurality of layers, based on the intermediate basis set;
• and
• transmitting the CSI report including a pre-coding matrix indicator (PMI) regarding the N′ basis vectors included in the intermediate basis set and the Ml basis vectors included in the basis subset, to a base station,
• wherein N, N′, and Ml are positive integers, N′<N, Ml<N′, and l is a value corresponding to a number of the one or more layers.