METHOD AND APPARATUS FOR ANTENNA DIVERSITY IN MULTI-INPUT MULTI-OUTPUT COMMUNICATION SYSTEMS

• US 20120140798A1
• Filed: 10/11/2011
• Published: 06/07/2012
• Est. Priority Date: 08/22/2005
• Status: Abandoned Application

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Kadous, Tamer, Khandekar, Aamod, Gore, Dhananjay Ashok, Gorokhov, Alexei
• Application Number:
  US13/271,108
• Publication Number:
  US 20120140798A1
• Time in Patent Office: Days
• US Class Current: 375/219
• 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 27/26035 Maintenance of orthogonality, e.g. for signals exchanged between cells or users, or by using covering codes or sequences using different training sequence per antenna H04B7/0684; code allocation H04J13/16
• 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;

select a plurality of virtual antennas to use for transmission from among a plurality of virtual antennas;

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

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

apply different cyclic delays for each respective transmit antenna in a plurality of transmit antennas to the output symbols to create a transmit vector;

provide the transmit vector to the plurality of transmit antennas; and

a memory coupled to the at least one processor.

2. The apparatus of claim 1, wherein the cyclic delays are applied by circularly shifting a sequence of time-domain samples for each antenna in the plurality of transmit antennas.

3. The apparatus of claim 1, wherein the cyclic delays are applied by applying a phase ramp across subcarriers for each of the transmit antennas in the plurality of transmit antennas.

4. The apparatus of claim 1, wherein the processor is further configured to append a cyclic prefix to the transmit vector after applying the different cyclic delays.

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

14. The apparatus of claim 10, further comprising at least one of a base station and a terminal, with which the apparatus of claim 1 is integrated.

6. A method, comprising:

receiving a data vector;

selecting a plurality of virtual antennas to use for transmission from among a plurality of virtual antennas;

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

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

applying different cyclic delays for each respective transmit antenna in a plurality of transmit antennas to the output symbols to create a transmit vector; and

providing the transmit vector to the plurality of transmit antennas.

7. The method of claim 6, further comprising applying the cyclic delays by circularly shifting a sequence of time-domain samples for each antenna in the plurality of transmit antennas.

8. The method of claim 6, further comprising applying the cyclic delays by applying a phase ramp across subcarriers for each of the transmit antennas in the plurality of transmit antennas.

9. The method of claim 6, further comprising appending a cyclic prefix to the transmit vector after applying the different cyclic delays.

10. An apparatus, comprising:

means for receiving a data vector;

means for selecting a plurality of virtual antennas to use for transmission from among a plurality of virtual antennas;

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;

means for applying different cyclic delays for each respective transmit antenna in a plurality of transmit antennas to the output symbols to create a transmit vector; and

means for providing the transmit vector to the plurality of transmit antennas.

11. The apparatus of claim 10, wherein the cyclic delays are applied by circularly shifting a sequence of time-domain samples for each antenna in the plurality of transmit antennas.

12. The apparatus of claim 10, wherein the cyclic delays are applied by applying a phase ramp across subcarriers for each of the transmit antennas in the plurality of transmit antennas.

13. The apparatus of claim 10, further comprising means for appending a cyclic prefix to the transmit vector after applying the different cyclic delays.

15. A non-transitory computer-readable medium, comprising instructions stored thereon that, if executed by a processor, cause the processor to execute a method comprising:

receiving a data vector;

selecting a plurality of virtual antennas to use for transmission from among a plurality of virtual antennas;

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

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

applying different cyclic delays for each respective transmit antenna in a plurality of transmit antennas to the output symbols to create a transmit vector; and

providing the transmit vector to the plurality of transmit antennas.

16. The non-transitory computer-readable medium of claim 15, wherein the method further comprises applying the cyclic delays by circularly shifting a sequence of time-domain samples for each antenna in the plurality of transmit antennas.

17. The non-transitory computer-readable medium of claim 15, wherein the method further comprises applying the cyclic delays by applying a phase ramp across subcarriers for each of the transmit antennas in the plurality of transmit antennas.

18. The non-transitory computer-readable medium of claim 15, wherein the method further comprises appending a cyclic prefix to the transmit vector after applying the different cyclic delays.

19. The non-transitory computer-readable medium of claim 15, further comprising at least one of a base station and a terminal, with which the computer-readable medium of claim 15 is integrated.