METHOD OF TRANSMITTING USING PHASE SHIFT-BASED PRECODING AND APPARATUS FOR IMPLEMENTING THE SAME IN A WIRELESS COMMUNICATION SYSTEM

• US 20080205533A1
• Filed: 09/19/2007
• Published: 08/28/2008
• Est. Priority Date: 09/19/2006
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Jae Wan, Park, Sung Ho, Ihm, Bin Chul, Lee, Moon Il, Lee, Wook Bong
• Granted Patent: US 7,881,395 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/1816 with retransmission of the same, encoded, message
• CPC Class Codes: H04L 2025/03414 Multicarrier
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A method of transmitting data using a plurality of subcarriers in a multi-antenna wireless communication system is disclosed. More specifically, the method includes receiving feedback information from a mobile station (MS), performing channel encoding and modulation independently on user data to be transmitted by each antenna using the received feedback information, determining a phase shift-based precoding matrix for increasing a phase angle of the user data by a fixed amount, and performing precoding using the determined phase shift-based precoding matrix on the user data.

Claims

1. A method of transmitting data using a plurality of subcarriers in a multi-antenna wireless communication system, the method comprising:

receiving feedback information from a mobile station (MS);

performing channel encoding and modulation independently on user data to be transmitted by each antenna using the received feedback information;

determining a phase shift-based precoding matrix for increasing a phase angle of the user data by a fixed amount; and

performing precoding using the determined phase shift-based precoding matrix on the user data.

2. The method of claim 1, wherein the phase shift-based precoding matrix determining step includes using a first matrix for phase shifting and multiplying a second matrix to the first matrix in order to make the first matrix into an unitary matrix.

3. The method of claim 2, wherein the first matrix is a diagonal matrix with uniformly increased phase angle in columns, and the second matrix is a phase shift-based precoding matrix which satisfies conditions of the unitary matrix.

4. The method of claim 3, wherein the second matrix is selected from a codebook, which includes a matrix having relatively lower spatial multiplexing rate, and is configured as a part of another matrix having relatively higher spatial multiplexing rate.

5. The method of claim 3, further comprising:

selecting from the second matrix a specified number of columns corresponding to spatial multiplexing rate; and

reconfiguring the second matrix with only the selected columns.

6. The method of claim 4, wherein is a product of multiplying the first matrix and the second matrix is

7. The method of claim 1, further comprising performing a codebook-based precoding for scheduling channel power for each transmit antenna.

8. The method of claim 1, wherein phase shift-based precoding matrix is

9. The method of claim 8, wherein the phase shift-based precoding matrix is derived by applying the phase shift-based precoding to an unitary matrix.

10. The method of claim 9, wherein phase shift-based precoding matrix satisfies two conditions, a first condition is

11. A transmitting and receiving device in a multi-user, multi-antenna communication system using a plurality of subcarriers, comprising:

a channel encoder and modulator configured to perform channel coding and modulation independently on user data for each antenna using feedback information from the receiving device; and

a first precoder configured to determine a phase shift-based precoding matrix and to perform precoding on the user data using the determined phase shift-based precoding matrix,

wherein the phase shift-based precoding matrix is determined based on increasing a phase angle of the user data for each antenna fixedly.

12. The device of claim 11, wherein the first precoder includes a matrix reconfiguration module for selecting a number of columns corresponding to the spatial multiplexing rate and reconfiguring the matrix using only the selected columns.

13. The device of claim 11, wherein the first precoder includes a precoding matrix determining module for determining the phase shift-based precoding matrix by multiplying a first matrix and a second matrix, the first matrix is associated with phase shifting and the second matrix is associated with converting the first matrix to an unitary matrix.

14. The device of claim 13, wherein the first matrix is a diagonal matrix in which phase angles are fixedly increased with respect to columns, and the second matrix is a matrix which satisfies conditions for an unitary matrix.

15. The device of claim 13, wherein is a product of multiplying the first matrix and the second matrix is

16. The device of claim 15, further comprising a matrix reconfiguration module for:

selecting from the second matrix a specified number of columns corresponding to spatial multiplexing rate; and

reconfiguring the second matrix with only the selected columns.

17. The device of claim 11, further comprising a second precoder for performing a codebook-based precoding for scheduling channel power for each transmit antenna.