CODEBOOK FEEDBACK METHOD AND APPARATUS FOR MULTIPLE-ANTENNA CHANNEL IN MIMO SYSTEM

摘要

A codebook feedback method and apparatus for a multiple-antenna channel in a Multiple Input Multiple Output (MIMO) system are provided. In an embodiment, a method (20) includes: detecting (21) a downlink multiple-antenna channel; determining (22) a first codeword in a first level codebook corresponding to the rank of R, where any codeword in the first level codebook is four diagonal matrices, two same 2×C block matrices exist on a diagonal line, and C column vectors of the 2×C block matrix are selected from Q1 discrete Fourier transform (DFT) beam vectors; feeding back (23) an index of the first codeword; determining (24) a second codeword in a second level codebook corresponding to the rank of R, where any codeword in the second level codebook is a 2C×R matrix, each column of the 2C×R matrix is formed of one C×1 beam selection vector and one C×1 beam selection vector including phase offset information; and feeding back (25) an index of the second codeword. The foregoing solution introduces an orthogonal DFT beam selection in two-level codebook index feedback, and therefore becomes more suitable for an MIMO application of a cross-polarized configuration of four downlink transmit antennas.

主权项

1. A method of feedback for a 4-antenna downlink channel in a Multiple Input Multiple Output (MIMO) system, comprising:
detecting a downlink multiple-antenna channel; determining a first codeword in a first level codebook corresponding to the rank of R according to a long-term broadband channel characteristic estimated from a result of the detection, wherein any codeword in the first level codebook is four diagonal matrices, two same 2×C block matrices exist on a diagonal line, and C column vectors of the 2×C block matrix are selected from Q1 discrete Fourier transform (DFT) beam vectors; feeding back an index of the first codeword; determining a second codeword in a second level codebook corresponding to the rank of R according to a short-term channel characteristic estimated from the result of the detection and the first codeword, wherein any codeword in the second level codebook is a 2C×R matrix, and each column of the 2C×R matrix is formed of one C×1 beam selection vector and one C×1 beam selection vector comprising phase offset information; and feeding back an index of the second codeword.