Method and apparatus of using CDD like schemes with UE-RS based open loop beamforming

• US 8,934,560 B2
• Filed: 10/05/2011
• Issued: 01/13/2015
• Est. Priority Date: 10/07/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Bhattad, Kapil, Gaal, Peter
• Primary Examiner(s): Fan, Chieh
• Assistant Examiner(s): Garcia, Santiago
• Application Number:
  US13/253,747
• Publication Number:
  US 20120087401A1
• Time in Patent Office: 1,196 Days
• Field of Search: 375/267
• US Class Current: 375/267
• CPC Class Codes: H04B 7/0478 Special codebook structures directed to feedback optimisation
• CPC Class Codes: H04B 7/0486 taking channel rank into account
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• 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

Abstract

A method and apparatus of wireless communication are disclosed. The wireless communication performs pilot signal transmissions using a first precoding matrix for user equipment specific pilot signals, the pilot signal transmissions having a first transmission rank. The wireless communication also performs data transmissions using a second precoding matrix for data when the data transmissions have a second transmission rank less than the first transmission rank, in which the second precoding matrix includes a transformed version of the first precoding matrix. Alternatively, the wireless communication can perform data transmissions using at least two precoding matrices for data when the data transmissions have a second transmission rank less than or equal to the first transmission rank. Accordingly, the precoding matrix used for data is a transformed version of the precoding matrix used for user equipment specific pilot signals.

Claims

1. A wireless communication method, comprising:

performing pilot signal transmissions using a precoding matrix for user equipment specific pilot signals, the pilot signal transmissions having a first transmission rank; and

performing data transmissions using at least two precoding matrices for data, the data transmissions having a second transmission rank less than or equal to the first transmission rank,

wherein the at least two precoding matrices used for data includes a transformed version of the precoding matrix used for the user equipment specific pilot signals.

2. The method of claim 1, further including determining the first transmission rank and the second transmission rank based on user equipment feedback or uplink measurements.

3. The method of claim 1, further including providing the first transmission rank and the second transmission rank to a user equipment.

4. The method of claim 1, wherein the transformed version of the precoding matrix is performed as a function of at least an orthogonal frequency division multiplex (OFDM) symbol number, a subcarrier index, or parameters of a user equipment.

5. The method of claim 1, further including conveying information to a user equipment to transform channel estimates obtained from user equipment reference signals (UE-RS) in order to obtain channel estimates for demodulating the data.

6. A wireless communication apparatus, comprising:

means for performing pilot signal transmissions using a precoding matrix for user equipment specific pilot signals, the pilot signal transmissions having a first transmission rank; and

means for performing data transmissions using at least two precoding matrices for data, the data transmissions having a second transmission rank equal to the first transmission rank,

wherein the at least two precoding matrices used for data includes a transformed version of the precoding matrix used for the user equipment specific pilot signals.

7. The apparatus of claim 6, further including means for determining the first transmission rank and the second transmission rank based on user equipment feedback or uplink measurements.

8. The apparatus of claim 6, further including means for providing the first transmission rank and the second transmission rank to a user equipment.

9. The apparatus of claim 6, wherein the transformed version of the precoding matrix is performed as a function of at least an orthogonal frequency division multiplex (OFDM) symbol number, a subcarrier index, or parameters of a user equipment.

10. The apparatus of claim 6, further including means for conveying information to a user equipment to transform channel estimates obtained from user equipment reference signals (UE-RS) in order to obtain channel estimates for demodulating the data.

11. A wireless communication apparatus, comprising:

a memory for storing instructions to;

perform pilot signal transmissions using a precoding matrix for user equipment specific pilot signals, the pilot signal transmissions having a first transmission rank; and

perform data transmissions using at least two precoding matrices for data, the data transmissions having a second transmission rank equal to the first transmission rank,

wherein the at least two precoding matrices used for data includes a transformed version of the precoding matrix used for the user equipment specific pilot signals; and

a processor for executing the instructions.

12. A computer program product comprising a non-transitory computer readable medium storing instructions, the instructions comprising:

code for performing pilot signal transmissions using a precoding matrix for user equipment specific pilot signals, the pilot signal transmissions having a first transmission rank; and

code for performing data transmissions using at least two precoding matrices for data, the data transmissions having a second transmission rank equal to the first transmission rank,

wherein the at least two precoding matrices used for data includes a transformed version of the precoding matrix used for the user equipment specific pilot signals.

13. A wireless communication method, comprising:

receiving pilot signal transmissions using a precoding matrix for user equipment specific pilot signals, the pilot signal transmissions having a first transmission rank; and

receiving data transmissions using at least two precoding matrices for data, the data transmissions having a second transmission rank equal to the first transmission rank,

wherein the at least two precoding matrices used for data includes a transformed version of the precoding matrix used for user equipment specific pilot signals.

14. The method of claim 13, further including receiving values of the first transmission rank and the second transmission rank.

15. A wireless communication apparatus, comprising:

means for receiving pilot signal transmissions using a precoding matrix for user equipment specific pilot signals, the pilot signal transmissions having a first transmission rank; and

means for receiving data transmissions using at least two precoding matrices for data, the data transmissions having a second transmission rank equal to the first transmission rank,

wherein the at least two precoding matrices used for data is includes a transformed version of the precoding matrix used for user equipment specific pilot signals.

16. The apparatus of claim 15, further including means for receiving values of the first transmission rank and the second transmission rank.

17. A wireless communication apparatus, comprising:

a memory for storing instructions to;

receive pilot signal transmissions using a precoding matrix for user equipment specific pilot signals, the pilot signal transmissions having a first transmission rank; and

receive data transmissions using at least two precoding matrices for data, the data transmissions having a second transmission rank equal to the first transmission rank,

wherein the at least two precoding matrices used for data is includes a transformed version of the precoding matrix used for user equipment specific pilot signals; and

a processor for executing the instructions.

18. A computer program product comprising a non-transitory tangible computer readable medium storing instructions, the instructions comprising:

code for receiving pilot signal transmissions using a precoding matrix for user equipment specific pilot signals, the pilot signal transmissions having a first transmission rank; and

code for receiving data transmissions using at least two precoding matrices for data, the data transmissions having a second transmission rank equal to the first transmission rank,

wherein the at least two precoding matrices used for data is includes a transformed version of the precoding matrix used for user equipment specific pilot signals.