ENABLING PHASE TRACKING FOR A COMMUNICATION DEVICE

• US 20110134899A1
• Filed: 12/06/2010
• Published: 06/09/2011
• Est. Priority Date: 12/07/2009
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Jones, Vincent Knowles IV, Sampath, Hemanth, Van Nee, Didier Johannes Richard
• Granted Patent: US 9,288,096 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04L 1/0618 Space-time coding
• CPC Class Codes: H04L 27/2657 Carrier synchronisation
• CPC Class Codes: H04L 27/2675 Pilot or known symbols
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver

Abstract

A communication device for enabling phase tracking is described. The communication device includes a processor and instructions stored in memory. The communication device generates a plurality of pilot symbols. The pilot symbols conform to a rank-deficient pilot mapping matrix. The communication device also transmits the plurality of pilot symbols.

Claims

1. A communication device for enabling phase tracking, comprising:

a processor;

memory in electronic communication with the processor;

instructions stored in the memory, the instructions being executable to;

generate a plurality of pilot symbols, wherein the pilot symbols conform to a rank-deficient pilot mapping matrix; and

transmit the plurality of pilot symbols.

2. The communication device of claim 1, wherein the instructions are further executable to transmit data or training symbols.

3. The communication device of claim 2, wherein the data or training symbols are Orthogonal Frequency-Division Multiplexing (OFDM) data or training symbols.

4. The communication device of claim 1, wherein the pilot symbols are Orthogonal Frequency-Division Multiplexing (OFDM) pilot symbols.

5. The communication device of claim 1, wherein the rank-deficient pilot mapping matrix comprises at least one pair of identical pilot symbols.

6. The communication device of claim 1, wherein the rank-deficient pilot mapping matrix is a rank-deficient pilot mapping matrix R, wherein each row corresponds to pilot symbols transmitted on a different spatial stream and each column corresponds to pilot symbols transmitted on different Orthogonal Frequency-Division Multiplexing (OFDM) symbols.

7. The communication device of claim 1, wherein the rank-deficient pilot mapping matrix for four spatial streams and four Orthogonal Frequency-Division Multiplexing (OFDM) symbols is

8. The communication device of claim 1, wherein the rank-deficient pilot mapping matrix for six spatial streams and six Orthogonal Frequency-Division Multiplexing (OFDM) symbols is

9. The communication device of claim 1, wherein the rank-deficient pilot mapping matrix for eight spatial streams and eight Orthogonal Frequency-Division Multiplexing (OFDM) symbols is

10. The communication device of claim 1, wherein the plurality of pilot symbols is transmitted during a training period.

11. The communication device of claim 10, wherein the training period comprises Very High Throughput-Long Training Field (VHT-LTF) symbols transmitted according to Institute of Electrical and Electronics Engineers (IEEE) 802.11ac specifications.

12. The communication device of claim 10, wherein the pilot symbols are transmitted on tones reserved for pilot tones in Very High Throughput-Long Training Fields (VHT-LTFs).

13. The communication device of claim 1, wherein the communication device is a wireless communication device.

14. A communication device for tracking phase, comprising:

a processor;

memory in electronic communication with the processor;

instructions stored in the memory, the instructions being executable to;

receive a plurality of pilot symbols from a sending communication device, wherein the pilot symbols conform to a rank-deficient pilot mapping matrix;

determine a phase estimate based on the pilot symbols;

estimate a channel based on the phase estimate and the pilot symbols; and

receive data from the sending communication device using the channel estimate.

15. The communication device of claim 14, wherein the pilot symbols are Orthogonal Frequency-Division Multiplexing (OFDM) pilot symbols.

16. The communication device of claim 14, wherein the rank-deficient pilot mapping matrix comprises at least one pair of identical pilot symbols.

17. The communication device of claim 14, wherein the rank-deficient pilot mapping matrix is a rank-deficient pilot mapping matrix R, wherein each row corresponds to pilot symbols transmitted on a different spatial stream and each column corresponds to pilot symbols transmitted on different Orthogonal Frequency-Division Multiplexing (OFDM) symbols.

18. The communication device of claim 14, wherein the phase estimate is determined based on identical pilot symbols transmitted on all spatial streams but across different Orthogonal Frequency-Division Multiplexing (OFDM) symbols.

19. The communication device of claim 16, wherein the instructions are further executable to determine the phase estimate based on the at least one pair of identical pilot symbols.

20. The communication device of claim 16, wherein the phase estimate is determined by computing a cross-correlation of the identical pilot symbols.

21. The communication device of claim 16, wherein the phase estimate is determined by computing a phase delta of the identical pilot symbols.

22. The communication device of claim 14, wherein the phase estimate is determined by computing a cross-correlation of identical pilot symbols transmitted on all spatial streams but across different Orthogonal Frequency-Division Multiplexing (OFDM) symbols.

23. The communication device of claim 14, wherein the phase estimate is determined by computing a phase delta of identical pilot symbols transmitted on all spatial streams but across different Orthogonal Frequency-Division Multiplexing (OFDM) symbols.

24. The communication device of claim 14, wherein the plurality of pilot symbols is received during a training period.

25. The communication device of claim 24, wherein the training period comprises Very High Throughput-Long Training Field (VHT-LTF) symbols transmitted according to Institute of Electrical and Electronics Engineers (IEEE) 802.11ac specifications.

26. The communication device of claim 14, wherein the phase estimate is determined during a training period.

27. The communication device of claim 26, wherein the training period comprises Very High Throughput-Long Training Field (VHT-LTF) symbols transmitted according to Institute of Electrical and Electronics Engineers (IEEE) 802.11ac specifications.

28. The communication device of claim 14, wherein the channel is estimated during a training period.

29. The communication device of claim 28, wherein the training period comprises Very High Throughput-Long Training Field (VHT-LTF) symbols transmitted according to Institute of Electrical and Electronics Engineers (IEEE) 802.11ac specifications.

30. The communication device of claim 14, wherein the communication device is a base station.

31. A method for enabling phase tracking, comprising:

generating, on a communication device, a plurality of pilot symbols, wherein the pilot symbols conform to a rank-deficient pilot mapping matrix; and

transmitting the plurality of pilot symbols.

32. The method of claim 31, further comprising transmitting data or training symbols.

33. The method of claim 32, wherein the data or training symbols are Orthogonal Frequency-Division Multiplexing (OFDM) data or training symbols.

34. The method of claim 31, wherein the pilot symbols are Orthogonal Frequency-Division Multiplexing (OFDM) pilot symbols.

35. The method of claim 31, wherein the rank-deficient pilot mapping matrix comprises at least one pair of identical pilot symbols.

36. The method of claim 31, wherein the rank-deficient pilot mapping matrix is a rank-deficient pilot mapping matrix R, wherein each row corresponds to pilot symbols transmitted on a different spatial stream and each column corresponds to pilot symbols transmitted on different Orthogonal Frequency-Division Multiplexing (OFDM) symbols.

37. The method of claim 31, wherein the rank-deficient pilot mapping matrix for four spatial streams and four Orthogonal Frequency-Division Multiplexing (OFDM) symbols is

38. The method of claim 31, wherein the rank-deficient pilot mapping matrix for six spatial streams and six Orthogonal Frequency-Division Multiplexing (OFDM) symbols is

39. The method of claim 31, wherein the rank-deficient pilot mapping matrix for eight spatial streams and eight Orthogonal Frequency-Division Multiplexing (OFDM) symbols is

40. The method of claim 31, wherein the plurality of pilot symbols is transmitted during a training period.

41. The method of claim 40, wherein the training period comprises Very High Throughput-Long Training Field (VHT-LTF) symbols transmitted according to Institute of Electrical and Electronics Engineers (IEEE) 802.11ac specifications.

42. The method of claim 40, wherein the pilot symbols are transmitted on tones reserved for pilot tones in Very High Throughput-Long Training Fields (VHT-LTFs).

43. The method of claim 31, wherein the communication device is a wireless communication device.

44. A method for tracking phase, comprising:

receiving, by a communication device, a plurality of pilot symbols from a sending communication device, wherein the pilot symbols conform to a rank-deficient pilot mapping matrix;

determining, by the communication device, a phase estimate based on the pilot symbols;

estimating a channel based on the phase estimate and the pilot symbols; and

receiving data from the sending communication device using the channel estimate.

45. The method of claim 44, wherein the pilot symbols are Orthogonal Frequency-Division Multiplexing (OFDM) pilot symbols.

46. The method of claim 44, wherein the rank-deficient pilot mapping matrix comprises at least one pair of identical pilot symbols.

47. The method of claim 44, wherein the rank-deficient pilot mapping matrix is a rank-deficient pilot mapping matrix R, wherein each row corresponds to pilot symbols transmitted on a different spatial stream and each column corresponds to pilot symbols transmitted on different Orthogonal Frequency-Division Multiplexing (OFDM) symbols.

48. The method of claim 44, wherein the phase estimate is determined based on identical pilot symbols transmitted on all spatial streams but across different Orthogonal Frequency-Division Multiplexing (OFDM) symbols.

49. The method of claim 46, further comprising determining the phase estimate based on the at least one pair of identical pilot symbols.

50. The method of claim 46, wherein the phase estimate is determined by computing a cross-correlation of the identical pilot symbols.

51. The method of claim 46, wherein the phase estimate is determined by computing a phase delta of the identical pilot symbols.

52. The method of claim 44, wherein the phase estimate is determined by computing a cross-correlation of identical pilot symbols transmitted on all spatial streams but across different Orthogonal Frequency-Division Multiplexing (OFDM) symbols.

53. The method of claim 44, wherein the phase estimate is determined by computing a phase delta of identical pilot symbols transmitted on all spatial streams but across different Orthogonal Frequency-Division Multiplexing (OFDM) symbols.

54. The method of claim 44, wherein the plurality of pilot symbols is received during a training period.

55. The method of claim 54, wherein the training period comprises Very High Throughput-Long Training Field (VHT-LTF) symbols transmitted according to Institute of Electrical and Electronics Engineers (IEEE) 802.11ac specifications.

56. The method of claim 44, wherein the phase estimate is determined during a training period.

57. The method of claim 56, wherein the training period comprises Very High Throughput-Long Training Field (VHT-LTF) symbols transmitted according to Institute of Electrical and Electronics Engineers (IEEE) 802.11ac specifications.

58. The method of claim 44, wherein the channel is estimated during a training period.

59. The method of claim 58, wherein the training period comprises Very High Throughput-Long Training Field (VHT-LTF) symbols transmitted according to Institute of Electrical and Electronics Engineers (IEEE) 802.11ac specifications.

60. The method of claim 44, wherein the communication device is a base station.

61. A computer-program product for enabling phase tracking comprising a non-transitory tangible computer-readable medium having instructions thereon, the instructions comprising:

code for causing a communication device to generate a plurality of pilot symbols, wherein the pilot symbols conform to a rank-deficient pilot mapping matrix; and

code for causing the communication device to transmit the plurality of pilot symbols.

62. The computer-program product of claim 61, wherein the plurality of pilot symbols is transmitted during a training period.

63. A computer-program product for tracking phase comprising a non-transitory tangible computer-readable medium having instructions thereon, the instructions comprising:

code for causing a communication device to receive a plurality of pilot symbols from a sending communication device, wherein the pilot symbols conform to a rank-deficient pilot mapping matrix;

code for causing the communication device to determine a phase estimate based on the pilot symbols;

code for causing the communication device to estimate a channel based on the phase estimate and the pilot symbols; and

code for causing the communication device to receive data from the sending communication device using the channel estimate.

64. The computer-program product of claim 63, wherein the phase estimate is determined during a training period.

65. An apparatus for enabling phase tracking, comprising:

means for generating a plurality of pilot symbols, wherein the pilot symbols conform to a rank-deficient pilot mapping matrix; and

means for transmitting the plurality of pilot symbols.

66. The apparatus of claim 65, wherein the plurality of pilot symbols is transmitted during a training period.

67. An apparatus for tracking phase, comprising:

means for receiving a plurality of pilot symbols from a sending communication device, wherein the pilot symbols conform to a rank-deficient pilot mapping matrix;

means for determining a phase estimate based on the pilot symbols;

means for estimating a channel based on the phase estimate and the pilot symbols; and

means for receiving data from the sending communication device using the channel estimate.

68. The apparatus of claim 67, wherein the phase estimate is determined during a training period.