Patent ID: 8582627

Claim:
A method in a wireless communication transceiver, wherein another transceiver precodes transmissions to the transceiver based at least in part on the transceiver sending channel state information to the other transceiver that includes precoder information and wherein the method comprises: selecting entries from one or more codebooks as a selected conversion precoder and a selected tuning precoder, or as a selected overall precoder corresponding to a selected conversion precoder and a selected tuning precoder; and transmitting indications of the selected entries as said precoder information included in the channel state information; wherein the one or more codebooks include entries comprising N T Q different conversion precoders and entries comprising a number of corresponding tuning precoders, or include entries comprising a plurality of overall precoders, with each overall precoder comprises a product of a conversion precoder and a tuning precoder; and wherein each said conversion precoder out of said N T Q different entries comprises a block diagonal matrix in which each block comprises a Discrete Fourier Transform (DFT)-based antenna-subgroup precoder that corresponds to a subgroup of N T transmit antenna ports and provides N T Q different DFT based beams for the corresponding subgroup, where Q is an integer value and where the N T Q different conversion precoders, together with one or more of the tuning precoders, correspond to a set of N T Q different overall precoders, wherein each overall precoder represents a size-N T DFT-based beam over the N T transmit antenna ports.