PRECODER STRUCTURE FOR MIMO PRECODING

摘要

The teachings herein present a method and apparatus that implement and use a factorized precoder structure that is advantageous in terms of performance and efficiency. In particular, the teachings presented herein disclose an underlying precoder structure that allows for certain codebook reuse across different transmission scenarios, including for transmission from a single Uniform Linear Array (ULA) of transmit antennas and transmission from cross-polarized subgroups of such antennas. According to this structure, an overall precoder is constructed from a conversion precoder and a tuning precoder. The conversion precoder includes antenna-subgroup precoders of size NT/2, where NT represents the number of overall antenna ports considered. Correspondingly, the tuning precoder controls the offset of beam phases between the antenna-subgroup precoders, allowing the conversion precoder to be used with cross-polarized arrays of NT/2 antenna elements and with co-polarized arrays of NT antenna elements.

主权项

1. 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 NTQ 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 the product of a conversion precoder and a tuning precoder; and wherein each said conversion precoder out of said NTQ 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 NT transmit antenna ports and provides NTQ different DFT based beams for the corresponding subgroup, where Q is an integer value and where the NTQ different conversion precoders, together with one or more of the tuning precoders, correspond to a set of NTQ different overall precoders, wherein each overall precoder represents a size-NT DFT-based beam over the NT transmit antenna ports.