Method and apparatus for antenna diversity in multi-input multi-output communication systems

• US 9,860,033 B2
• Filed: 10/11/2011
• Issued: 01/02/2018
• Est. Priority Date: 08/22/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Kadous, Tamer, Khandekar, Aamod, Gore, Dhananjay Ashok, Gorokhov, Alexei
• Primary Examiner(s): TSE, YOUNG TOI
• Application Number:
  US13/271,113
• Publication Number:
  US 20120140838A1
• Time in Patent Office: 2,275 Days
• Field of Search: 375135, 375146, 375260, 375262, 375265, 375267, 375299, 370208, 455500, 455 69, 455101
• CPC Class Codes: H04B 7/0456 Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
• CPC Class Codes: H04B 7/061 using feedback from receiving side
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04B 7/0697 using spatial multiplexing
• CPC Class Codes: H04L 5/0023 Time-frequency-space

Abstract

Transmission schemes that can flexibly achieve the desired spatial multiplexing order, spatial diversity order, and channel estimation overhead order are described. For data transmission, the assigned subcarriers and spatial multiplexing order (M) for a receiver are determined, where M≧1. For each assigned subcarrier, M virtual antennas are selected from among V virtual antennas formed with V columns of an orthonormal matrix, where V≧M. V may be selected to achieve the desired spatial diversity order and channel estimation overhead order. Output symbols are mapped to the M virtual antennas selected for each assigned subcarrier by applying the orthonormal matrix. Pilot symbols are also mapped to the V virtual antennas. The mapped symbols are provided for transmission from T transmit antennas, where T≧V. Transmission symbols are generated for the mapped symbols, e.g., based on OFDM or SC-FDMA. Different cyclic delays may be applied for the T transmit antennas to improve diversity.

Claims

1. An apparatus, comprising:

at least one processor configured to;

receive a data vector;

receive feedback from a receiver;

select, based on the feedback, a plurality of virtual antennas representing antenna ports;

form a permutation matrix indicative of the plurality of virtual antennas selected;

apply the permutation matrix to the data vector to create output symbols; and

provide the output symbols to the antenna ports; and

a memory coupled to the at least one processor.

2. The apparatus of claim 1, wherein the at least one processor is further configured to use an orthonormal matrix to form the plurality of virtual antennas.

3. The apparatus of claim 2, wherein the at least one processor is further configured to select the orthonormal matrix from among a plurality of orthonormal matrices available to form the plurality of virtual antennas.

4. The apparatus of claim 3, wherein the at least one processor is further configured to select, based on the feedback, the orthonormal matrix from among the plurality of orthonormal matrices available to form the plurality of virtual antennas.

5. The apparatus of claim 1, further comprising at least one of a base station or a terminal, with which the at least one processor is integrated.

6. The apparatus of claim 1, wherein there are a quantity of V virtual transmit antennas in the plurality of virtual antennas, a quantity of T transmit antennas in a plurality of transmit antennas, the at least one processor is further configured to use an orthonormal T×

V matrix to form the quantity of V virtual transmit antennas, and the at least one processor is further configured to define the orthonormal T×

V matrix such that a sum of a squared magnitude of V entries in each row of the orthonormal T×

V matrix is equal to a constant value.

7. The apparatus of claim 1, wherein the feedback indicates specific virtual antennas in the plurality of virtual antennas to use for all assigned subcarriers.

8. The apparatus of claim 1, wherein the feedback indicates specific virtual antennas in the plurality of virtual antennas to use for each assigned subcarrier.

9. The apparatus of claim 1, wherein the at least one processor is further configured to:

estimate an uplink channel response based on a received pilot;

estimate a downlink channel response based on the uplink channel response estimate; and

use the downlink channel response estimate to select the plurality of virtual antennas.

10. A method, comprising:

receiving a data vector;

receiving feedback from a receiver;

selecting, based on the feedback, a plurality of virtual antennas representing antenna ports;

forming a permutation matrix indicative of the plurality of virtual antennas selected;

applying the permutation matrix to the data vector to create output symbols; and

providing the output symbols to the antenna ports.

11. The method of claim 10, further comprising using an orthonormal matrix to form the plurality of virtual antennas.

12. The method of claim 11, further comprising selecting the orthonormal matrix from among a plurality of orthonormal matrices available to form the plurality of virtual antennas.

13. The method of claim 12, further comprising selecting, based on the feedback, the orthonormal matrix from among the plurality of orthonormal matrices available to form the plurality of virtual antennas.

14. An apparatus, comprising:

means for receiving a data vector;

means for receiving feedback from a receiver;

means for selecting, based on the feedback, a plurality of virtual antennas representing antenna ports;

means for forming a permutation matrix indicative of the plurality of virtual antennas selected;

means for applying the permutation matrix to the data vector to create output symbols; and

means for providing the output symbols to the antenna ports.

15. The apparatus of claim 14, further comprising means for using an orthonormal matrix to form the plurality of virtual antennas.

16. The apparatus of claim 15, further comprising means for selecting the orthonormal matrix from among a plurality of orthonormal matrices available to form the plurality of virtual antennas.

17. The apparatus of claim 16, further comprising means for selecting, based on the feedback, the orthonormal matrix from among the plurality of orthonormal matrices available to form the plurality of virtual antennas.

18. The apparatus of claim 14, further comprising at least one of a base station or a terminal, with which the means for receiving the data vector is integrated.

19. A non-transitory computer-readable medium, comprising processor-executable instructions stored thereon that are configured to cause a processor to:

receive a data vector;

receive feedback from a receiver;

select, based on the feedback, a plurality of virtual antennas representing antenna ports;

form a permutation matrix indicative of the plurality of virtual antennas selected;

apply the permutation matrix to the data vector to create output symbols; and

provide the output symbols to the antenna ports.

20. The non-transitory computer-readable medium of claim 19, wherein the processor-executable instructions are further configured to cause the processor to use an orthonormal matrix to form the plurality of virtual antennas.

21. The non-transitory computer-readable medium of claim 20, wherein the processor-executable instructions are further configured to cause the processor to select the orthonormal matrix from among a plurality of orthonormal matrices available to form the plurality of virtual antennas.

22. The non-transitory computer-readable medium of claim 21, wherein the processor-executable instructions are further configured to cause the processor to select, based on the feedback, the orthonormal matrix from among the plurality of orthonormal matrices available to form the plurality of virtual antennas.

23. An apparatus, comprising:

a processor that is integrated with at least one of a base station or a terminal; and

a memory, comprising processor-executable instructions stored thereon that are configured to cause the processor to;

receive a data vector;

receive feedback from a receiver;

select, based on the feedback, a plurality of virtual antennas representing antenna ports;

form a permutation matrix indicative of the plurality of virtual antennas selected;

apply the permutation matrix to the data vector to create output symbols; and

provide the output symbols to the antenna ports.