Selective virtual antenna transmission

• US 20070041464A1
• Filed: 03/15/2006
• Published: 02/22/2007
• Est. Priority Date: 08/22/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Kim, Byoung-Hoon, Kadous, Tamer
• Granted Patent: US 8,073,068 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• 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: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 1/20 using signal quality detector
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

Techniques for transmitting data from virtual antennas instead of physical antennas are described. Each virtual antenna may be mapped to some or all physical antennas by a different mapping. The performance of different sets of at least one virtual antenna is evaluated based on one or more metrics such as signal quality, throughput, overall rate, and so on. The virtual antenna set with the best performance is selected for use. If the virtual antenna selection is performed by the receiver, then channel state information for the selected virtual antenna set may be sent to the transmitter. The channel state information may convey the selected virtual antenna(s), the signal quality or rate(s) for the selected virtual antenna(s), one or more preceding matrices used to form the selected virtual antenna(s), and so on. The transmitter and/or receiver use the selected virtual antenna(s) for data transmission.

Claims

1. An apparatus comprising:

at least one processor configured to select at least one virtual antenna from among multiple virtual antennas formed with multiple physical antennas and to provide an indication of use of the at least one selected virtual antenna for data transmission; and

a memory coupled to the at least one processor.

2. The apparatus of claim 1, wherein the at least one processor is configured to evaluate multiple hypotheses, each hypothesis corresponding to a different set of at least one virtual antenna, and to select a hypothesis from among the multiple hypotheses, wherein the at least one selected virtual antenna is for the selected hypothesis.

3. The apparatus of claim 2, wherein the at least one processor is configured to determine performance of each of the multiple hypotheses based on at least one metric, and to select a hypothesis with best performance.

4. The apparatus of claim 2, wherein the at least one processor is configured to determine signal quality for each of the multiple hypotheses, and to select a hypothesis with highest signal quality.

5. The apparatus of claim 2, wherein the at least one processor is configured to determine throughput for each of the multiple hypotheses, and to select a hypothesis with highest throughput.

6. The apparatus of claim 2, wherein the at least one processor is configured to determine an overall rate for each of the multiple hypotheses, and to select a hypothesis with highest overall rate.

7. The apparatus of claim 2, wherein the at least one processor is configured to distribute total transmit power uniformly across the at least one virtual antenna for each of the multiple hypotheses.

8. The apparatus of claim 2, wherein the at least one processor is configured to distribute total transmit power non-uniformly across the at least one virtual antenna for each of the multiple hypotheses.

9. The apparatus of claim 1, wherein the at least one processor is configured to select at least one rate for the at least one selected virtual antenna based on signal quality for the at least one selected virtual antenna.

10. The apparatus of claim 1, wherein the at least one processor is configured to instruct sending the data transmission via the at least one selected virtual antenna coupled with the processor to a receiver.

11. The apparatus of claim 1, wherein the at least one processor is configured to send channel state information for the at least one selected virtual antenna to a transmitter and to receive the data transmission from the transmitter via the at least one selected virtual antenna.

12. The apparatus of claim 11, wherein the channel state information identifies the at least one selected virtual antenna.

13. The apparatus of claim 11, wherein the channel state information indicates signal quality or at least one rate for the at least one selected virtual antenna.

14. The apparatus of claim 11, wherein the channel state information indicates a base signal quality and at least one delta signal quality, wherein the base signal quality is for one selected virtual antenna or one data stream, and wherein the at least one delta signal quality is for remaining selected virtual antennas or remaining data streams.

15. The apparatus of claim 11, wherein the channel state information indicates at least one matrix used to form the at least one selected virtual antenna.

16. The apparatus of claim 1, wherein the multiple virtual antennas are formed with at least one matrix that maps each virtual antenna to the multiple physical antennas.

17. A method comprising:

selecting at least one virtual antenna from among multiple virtual antennas formed with multiple physical antennas; and

providing an indication of the at least one selected virtual antenna for use for data transmission.

18. The method of claim 17, wherein the selecting the at least one virtual antenna comprises

evaluating multiple hypotheses, each hypothesis corresponding to a different set of at least one virtual antenna, and

selecting a hypothesis from among the multiple hypotheses, wherein the at least one selected virtual antenna is for the selected hypothesis.

19. The method of claim 18, wherein the evaluating the multiple hypotheses comprises determining performance of each of the multiple hypotheses based on at least one metric, and wherein the selecting the hypothesis comprises selecting the hypothesis with best performance.

20. The method of claim 19, wherein the evaluating the multiple hypotheses comprises distributing total transmit power uniformly across the at least one virtual antenna for each of the multiple hypotheses.

21. The method of claim 17, further comprising:

sending channel state information for the at least one selected virtual antenna to a transmitter; and

receiving the data transmission from the transmitter via the at least one selected virtual antenna.

22. An apparatus comprising:

means for selecting at least one virtual antenna from among multiple virtual antennas formed with multiple physical antennas; and

means for providing an indication of the at least one selected virtual antenna for use for data transmission.

23. The apparatus of claim 22, wherein the means for selecting the at least one virtual antenna comprises

means for evaluating multiple hypotheses, each hypothesis corresponding to a different set of at least one virtual antenna, and

means for selecting a hypothesis from among the multiple hypotheses, wherein the at least one selected virtual antenna is for the selected hypothesis.

24. The apparatus of claim 23, wherein the means for evaluating the multiple hypotheses comprises means for determining performance of each of the multiple hypotheses based on at least one metric, and wherein the means for selecting the hypothesis comprises means for selecting the hypothesis with best performance.

25. The apparatus of claim 22, further comprising:

means for sending channel state information for the at least one selected virtual antenna to a transmitter; and

means for receiving the data transmission from the transmitter via the at least one selected virtual antenna.

26. A processor readable media for storing instructions operable to:

select at least one virtual antenna from among multiple virtual antennas formed with multiple physical antennas; and

use the at least one selected virtual antenna for data transmission.

27. An apparatus comprising:

at least one processor configured to receive channel state information for at least one virtual antenna selected from among multiple virtual antennas formed with multiple physical antennas, and to send a data transmission via the at least one selected virtual antenna; and

a memory coupled to the at least one processor.

28. The apparatus of claim 27, wherein the at least one processor is configured to distribute total transmit power uniformly across the at least one selected virtual antenna.

29. The apparatus of claim 27, wherein the at least one processor is configured to select at least one rate for the at least one selected virtual antenna based on the channel state information, and to send the data transmission at the at least one selected rate.

30. The apparatus of claim 27, wherein the at least one processor is configured to send at least one data stream for the data transmission, and to map each data stream to all of the at least one selected virtual antenna.

31. The apparatus of claim 30, wherein the at least one processor is configured to map each data stream to all of the at least one selected virtual antenna based on a predetermined stream permutation.

32. The apparatus of claim 30, wherein the at least one processor is configured to map each data stream to all of the at least one selected virtual antenna by cycling through the at least one selected virtual antenna across multiple subcarriers.

33. The apparatus of claim 27, wherein the at least one processor is configured to send at least one data stream for the data transmission, and to map each data stream to a respective selected virtual antenna.

34. The apparatus of claim 27, wherein the at least one processor is configured to receive channel state information indicative of at least one matrix to use to form the at least one selected virtual antenna, and to process the data transmission with the at least one matrix.

35. The apparatus of claim 34, wherein the at least one processor is configured to send at least one data stream for the data transmission, and to map each data stream to all of the at least one selected virtual antenna.

36. A method comprising:

receiving channel state information for at least one virtual antenna selected from among multiple virtual antennas formed with multiple physical antennas; and

sending a data transmission via the at least one selected virtual antenna.

37. The method of claim 36, further comprising:

distributing total transmit power across the at least one selected virtual antenna.

38. The method of claim 36, wherein the sending the data transmission comprises

selecting at least one rate for the at least one selected virtual antenna based on the channel state information, and

sending the data transmission at the at least one selected rate.

39. An apparatus comprising:

means for receiving channel state information for at least one virtual antenna selected from among multiple virtual antennas formed with multiple physical antennas; and

means for sending a data transmission via the at least one selected virtual antenna.

40. The apparatus of claim 39, further comprising:

means for distributing total transmit power across the at least one selected virtual antenna.

41. The apparatus of claim 39, wherein the means for sending the data transmission comprises

means for selecting at least one rate for the at least one selected virtual antenna based on the channel state information, and

means for sending the data transmission at the at least one selected rate.

42. A processor readable media for storing instructions operable to:

receive channel state information for at least one virtual antenna selected from among multiple virtual antennas formed with multiple physical antennas; and

send a data transmission via the at least one selected virtual antenna.