METHOD FOR DETERMINING PRECODING MATRIX AND CORRESPONDING COMMUNICATION METHODS AND DEVICES

• US 20130170578A1
• Filed: 08/24/2011
• Published: 07/04/2013
• Est. Priority Date: 09/16/2010
• Status: Active Grant

• Current Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Original Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Inventors: Wu, Lu, Chen, Jinhui, Song, Yang, Yang, Hongwei, Lv, Di, Liu, Hao
• Granted Patent: US 8,861,639 B2
• Time in Patent Office: Days
• US Class Current: 375/295
• CPC Class Codes: H04B 7/0426 Power distribution
• CPC Class Codes: H04B 7/0456 Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
• CPC Class Codes: H04B 7/0469 taking special antenna structures, e.g. cross polarized antennas into account
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/065 Variable contents, e.g. long-term or short-short
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end

Abstract

A method for determining precoding matrix for the sub-band precoding in a transmitter, wherein the transmitter has M transmitting antennas, and the method comprises: a. determining an optimized first matrix W₁ according to wideband and/or long-term channel properties, with the first matrix W₁ corresponding to wideband and/or long-term channel properties; b. multiplying the optimized first matrix W₁, with each second matrix W₂, in a second codebook, so as to obtain a plurality of candidate precoding matrices, the second matrix W₂ corresponds to frequency-selective and/or short-term channel properties; c. selecting an optimized one from the plurality of candidate preceding matrices for precoding the data to be transmitted, according to a frequency selection and/or a short-term channel state information; characterized in that, the amount of DFT beams is increased to improve the spatial resolution; a diagonal matrix is involved in said first matrix W₁; and phrase adjustment is involved in said second matrix W₂, so as to guarantee the adjusted phrase is evenly distributed among the whole phrase space.

Claims

1. A method for determining precoding matrix for the sub-band precoding in a transmitter, wherein the transmitter has M transmitting antennas, and the method comprises:

determining an optimized first matrix W₁ according to wideband and/or long-term channel properties, with the first matrix W₁ corresponding to wideband and/or long-term channel properties;

multiplying the optimized first matrix W₁ with each second matrix W₂ in a second codebook, so as to obtain a plurality of candidate precoding matrices, with the second matrix W₂ corresponding to frequency-selective and/or short-term channel properties;

selecting an optimized one from the plurality of candidate precoding matrices for precoding the data to be transmitted, according to a frequency selection and/or a short-term channel state information;

wherein, the amount of DFT beams is increased to improve the spatial resolution;

a diagonal matrix is involved in said first matrix W₁; and

phrase adjustment is involved in said second matrix W₂, so as to guarantee the adjusted phrase is evenly distributed among the whole phrase space.

2. A method as claimed in claim 1, wherein the amount of DFT beams is increased to improve the spatial resolution,

the first matrix W₁ is selected from the following first codebook C₁:

3. A method as claimed in claim 2, wherein the value of a is 1 when the polarization manner of the antennas is uniform linear array.

4. A method as claimed in claim 2, wherein when the polarization manner of the antennas is cross polarized linear array or when the same codebook is used for various polarization manner of the antennas, a is selected from a set {e^jβ

¹, e<sup>jβ

2</sup>, . . . , e<sub>jβ

m</sub>}, wherein m is the amount of values of a, the values of β

₁, β

₂, . . . , β

_m are selected in a range of [0,2π

), generally selected as evenly distributed among [0,2π

) namely

5. A method as claimed in claim 2, wherein, when the transmitter has 8 antenna elements, for codebook C₁,

6. A method, in the user equipments, for feeding precoding matrix for sub-band precoding back to an eNodeB, comprising:

determining the optimized first matrix W₁ and the precoding matrix, by using a method as claimed in claim 1;

determining an optimized second matrix W₂ corresponding to said optimized precoding matrix;

providing, for the eNodeB, identifications of said optimized first matrix W₁ and said second matrix W₂.

7. A method, in eNodeBs, for precoding data, comprising:

receiving identifications of an optimized first matrix W₁ and an optimized second matrix W₂, fed back by user equipments;

determining, from the first codebook and the second code book in a method according to claim 1, the optimized first matrix W₁ and the optimized second matrix W₂, according to the identifications;

multiplying the optimized first matrix W₁ and the optimized second matrix W₂, and obtaining an optimized precoding matrix;

precoding the data to be transmitted, by using the optimized precoding matrix.

8. A device, in user equipments, for feeding precoding matrix for sub-band precoding back to an eNodeB, comprising:

a determining means, for determining the optimized first matrix W₁ and the precoding matrix, by using a method as claimed in claim 1, and for determining an optimized second matrix W₂ corresponding to said optimized precoding matrix;

a sender, for providing, for the eNodeB, identifications of said optimized first matrix W₁ and said second matrix W₂.

9. A device, in eNodeBs, for precoding data, comprising:

a receiver, for receiving identifications of an optimized first matrix W₁ and an optimized second matrix W₂, fed back by user equipments;

an inquiring means, for determining, from the first codebook and the second code book in a method according to claim 1, the optimized first matrix W₁ and the optimized second matrix W₂, from the identifications;

a calculating means, for multiplying the optimized first matrix W₁ and the optimized second matrix W₂, and obtaining an optimized precoding matrix for the sub-band precoding;

a precoder, for precoding the data to be transmitted, by using the optimized precoding matrix.