EXTENSIONS TO ADAPTIVE BEAM-STEERING METHOD

• US 20080240031A1
• Filed: 03/25/2008
• Published: 10/02/2008
• Est. Priority Date: 03/26/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: SiBEAM, Inc. (Lattice Semiconductor Corporation)
• Inventors: Gilbert, Jeffrey M., Nassiri-Toussi, Karim
• Granted Patent: US 8,170,617 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0634 Antenna weights or vector/matrix coefficients
• CPC Class Codes: H04B 7/065 Variable contents, e.g. long-term or short-short
• CPC Class Codes: H04B 7/0848 Joint weighting
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04W 52/04 TPC

Abstract

A radio frequency (RF) transmitter is coupled to and controlled by a processor to transmit data. A physical layer circuit is coupled to the RF transmitter to encode and decode between a digital signal and a modulated analog signal. The physical layer circuit comprises a high rate physical layer circuit (HRP) and a low rate physical layer circuit (LRP). In a first embodiment, the LRP circuit generates a LRP packet comprising an LRP transmit power control feedback. In a second embodiment, the LRP and HRP circuit generate a packet comprising a beam-forming phase and magnitude feedback information. In a third embodiment, the LRP and HRP circuit supports up to 64 independent transmit antenna elements.

Claims

1. An apparatus comprising:

a transmitter having a first digital baseband processing unit coupled to a first phased array antenna system;

a receiver having a second digital baseband processing unit coupled to a second phased array antenna system, wherein the first and second digital baseband processing units cooperate to encode and decode between a digital signal and a modulated analog signal, the physical layer circuit comprising a high rate physical layer circuit and a low rate physical layer circuit; and

a feedback channel to feed back control information from the receiver to the transmitter, wherein the feedback channel physical layer comprises of a low rate physical circuit that is operable to produce data rates in the order of megabits per second, and to generate an LRP packet that includes transmit power control feedback information.

2. The apparatus of claim 1 wherein the high rate physical layer circuit is operable to produce data rates in the order of gigabits per second, wherein nominal transmission power step sizes of high rate channel are of 5 dB, and up to 4 steps.

3. The apparatus of claim 1 wherein the transmit power control information is fed back as part of the first beam-search LRP feedback.

4. The apparatus of claim 1 wherein the transmit power control information is coded into 4 codewords (0x0000, 0xFFC0, 0x03FF, 0xFC3F) with maximum Hamming distance.

5. An apparatus comprising:

a transmitter having a first digital baseband processing unit coupled to a first phased array antenna system;

a receiver having a second digital baseband processing unit coupled to a second phased array antenna system, wherein the first and second digital baseband processing units cooperate to encode and decode between a digital signal and a modulated analog signal, the physical layer circuit comprising a high rate physical layer circuit and a low rate physical layer circuit; and

a feedback channel to feed back control information from the receiver to the transmitter, wherein the feedback channel physical layer comprises of a low rate physical circuit that is operable to produce data rates in the order of megabits per second, and to generate a LRP packet that includes beam-forming phase and magnitude feedback information for transmit antennas.

6. The apparatus of claim 5 wherein the beam forming feedback for the high rate physical layer, which is operable to produce data rates in the order of gigabits per second, and the beam forming feedback for the low rate physical layer, which is operable to produce data rates in the order of megabits per second, includes a 72-bit transmit antenna weight vector.

7. The apparatus of claim 5 wherein the beam forming feedback for the high rate physical layer carries coarse phase information for higher number of transmit antennas, or fine phase information for lower number of transmit antennas, or phase and magnitude information for fewer number of transmit antennas.

8. The apparatus of claim 5 wherein the beam forming feedback for the high rate physical layer carries 2-bit phase information for 36 transmit antennas.

9. The apparatus of claim 5 wherein the beam forming feedback for the high rate physical layer carries 3-bit phase information for 24 transmit antennas.

10. The apparatus of claim 5 wherein the beam forming feedback for the high rate physical layer carries 4-bit phase information for 18 transmit antennas.

11. The apparatus of claim 5 wherein the beam forming feedback for the high rate physical layer carries 3-bit phase information and 3-bit magnitude information for 12 transmit antennas.

12. The apparatus of claim 5 wherein the beam forming feedback for the low rate physical layer carries 4-bit phase and 5-bit magnitude information for 8 transmit antennas.

13. The apparatus of claim 5 wherein the beam forming feedback for the high and low rate physical layers uses gray-coded mapping.

14. The apparatus of claim 5 wherein up to 12 antennas are used in a sectorized manner where the magnitude feedback information is used to select which one or more of the sectors to use.

15. An apparatus comprising:

a transmitter having a first digital baseband processing unit coupled to a first phased array antenna system;

a receiver having a second digital baseband processing unit coupled to a second phased array antenna system, wherein the first and second digital baseband processing units cooperate to encode and decode between a digital signal and a modulated analog signal, the physical layer circuit comprising a high rate physical layer circuit and a low rate physical layer circuit; and

a feedback channel to feed back control information from the receiver to the transmitter, wherein the feedback channel physical layer comprises of a low rate physical circuit that is operable to produce data rates in the order of megabits per second, and to generate LRP packet that includes beam steering feedback information, and wherein the high rate physical layer circuit is operable to support up to 64 transmit antenna elements coupled to the RF transmitter.

16. The apparatus of claim 15 wherein the high rate physical layer circuit is operable to produce data rates in the order of gigabits per second, and the low rate physical layer circuit is operable to produce data rates in the order of megabits per second.

17. The apparatus defined in claim 15 wherein the first and second digital baseband processing units cooperate to perform adaptive beam steering by

performing adaptive beam forming that includes a beam search process to identify a beam direction;

and

performing a beam tracking process to track the beam during a data transfer phase.

18. The apparatus defined in claim 15 wherein the receiver is operable to estimate a transmitter antenna-array weight vector and a receiver antenna-array weight vector.

19. The apparatus defined in claim 15 wherein the receiver is operable to set the receive weight vector while estimating the transmitter antenna-array weight vector and set the transmit weight vector while estimating the receiver antenna-array weight vector.

20. The apparatus defined in claim 15 wherein the first and second digital baseband processing units cooperate to perform beam search and adaptive beam steering by using a set of operations performed iteratively, the set of operations including

(a) the second digital baseband processing unit setting receive phase shifts for receive antennas of the second phased array antenna based on a first weight vector;

(b) the second digital baseband processing unit causing channel gains corresponding to each phase to be sequentially measured and forming a first set of channel gains;

(c) the second digital baseband processing unit calculating a second weight vector based on the first set of channel gains;

(d) the first digital baseband processing unit setting transmit phase shifts for transmit antennas of the first phased array antenna based on the second weight vector;

(e) the second digital baseband processing unit causing channel gains corresponding to each phase to be measured at the receiver and forming a second set of channel gains; and

(f) the second digital baseband processing unit calculating a third weight vector based on the second set of measured channel gains.

21. The apparatus defined in claim 20 wherein the second digital baseband processing unit estimates the transmitter antenna weight vector by estimating channel vector elements one at a time, wherein a number of sequential estimation slots is set to 64.

22. The apparatus defined in claim 20 wherein the second digital baseband processing unit estimates the transmitter antenna weight vector by using a 64-by-64 Hadamard-type matrix as a transfer matrix, such that transmit antenna weight vector is set to columns of the Hadamard-type matrix.

23. The apparatus defined in claim 20 wherein the set of operations further comprises the second digital baseband processing unit using the third weight vector in place of the first weight vector when setting receive phase shifts for the receive antennas for a next iteration, and then repeating operations (a) through (f).

24. The apparatus defined in claim 20 wherein the set of operations is performed for three iterations.

25. The apparatus defined in claim 15 wherein the first and second digital baseband processing units cooperate to perform timing recovery prior to iteratively performing the set of operations.

26. The apparatus defined in claim 20 wherein the first and second digital baseband processing units cooperate to perform delay estimation prior to iteratively performing the set of operations to determine the arrival time of the beam with maximum gain.

27. The apparatus defined in claim 15 wherein the first and second digital baseband processing units cooperate to perform delay estimation by:

the first digital baseband processing unit causing the first phased array antenna to transmit a known symbol sequence over the air; and

the second digital baseband processing unit causing the known symbol sequence to be matched at the receiver via a matched filter.

28. The apparatus defined in claim 15 wherein the beam tracking process comprises performing a single iteration of the pair of trainings defined in claim 20 in two operations for 64 transmit antennas, wherein the first 32 antennas are trained in a first operation, and the second 32 antennas are trained in a second operation.

29. The apparatus defined in claim 28 wherein the second digital baseband processing unit estimates the transmitter antenna weight vector by estimating channel vector elements one at a time, wherein a number of sequential estimation slots is set to 36.

30. The apparatus defined in claim 28 wherein the second digital baseband processing unit estimates the transmitter antenna weight vector by using a 36-by-36 Hadamard-type matrix as a transfer matrix, such that transmit antenna weight vector is set to columns of the Hadamard-type matrix.

31. The apparatus defined in claim 15 wherein the transmitter antenna weight vector that produces the strongest received signal at the receiver is repeated more than once during the sequential estimation of the transmitter antenna weight vector.

32. The apparatus defined in claim 15 wherein the second digital baseband processing unit sends an index of the transmit weight vector that produced the strongest received signal at the receiver during the sequential estimation of the transmitter antenna weight vector, from the receiver to the transmitter using the back channel.

60. The method of claim 47 further comprising performing a beam tracking process by performing a single iteration of the pair of trainings defined in claim 20 in two operations for 64 transmit antennas, wherein the first 32 antennas are trained in a first operation, and the second 32 antennas are trained in a second operation.

61. The method of claim 60 further comprising a second digital baseband processing unit estimating a transmitter antenna weight vector by estimating channel vector elements one at a time, wherein a number of sequential estimation slots is set to 36.

62. The method of claim 60 further comprising a second digital baseband processing unit estimating the transmitter antenna weight vector by using a 36-by-36 Hadamard-type matrix as a transfer matrix, such that transmit antenna weight vector is set to columns of the Hadamard-type matrix.

33. A method comprising:

generating a modulated analog signal to send, via a wireless communication channel, wherein generating the modulated analog signal further comprises

sending, on a feedback channel, control information as feedback from a receiver to a transmitter using a low rate physical circuit that is part of the feedback channel physical layer and is operable to produce data rates in the order of megabits per second, and to generate an LRP packet that includes transmit power control feedback information.

34. The method of claim 33 wherein the feedback channel comprises a high rate physical layer circuit operable to produce data rates in the order of gigabits per second, wherein nominal transmission power step sizes of high rate channel are of 5 dB, and up to 4 steps.

35. The method of claim 33 wherein the transmit power control information is fed back as part of the first beam-search LRP feedback.

36. The method of claim 33 wherein the transmit power control information is coded into 4 codewords (0x0000, 0xFFC0, 0x03FF, 0xFC3F) with maximum Hamming distance.

37. A method comprising:

generating a modulated analog signal to send, via a wireless communication channel, wherein generating the modulated analog signal further comprises

sending, on a feedback channel, control information as feedback from a receiver to a transmitter using a low rate physical circuit that is part of the feedback channel physical layer and is operable to produce data rates in the order of megabits per second, and to generate a LRP packet that includes beam-forming phase and magnitude feedback information for transmit antennas.

38. The method of claim 37 wherein the control information comprises beam forming feedback for a high rate physical layer, which is operable to produce data rates in the order of gigabits per second, and the beam forming feedback for the low rate physical layer, which is operable to produce data rates in the order of megabits per second, includes a 72-bit antenna weight vector.

39. The method of claim 37 wherein the control information comprises beam forming feedback for a high rate physical layer which comprises coarse phase information for higher number of transmit antennas, or fine phase information for lower number of transmit antennas, or phase and magnitude information for fewer number of transmit antennas.

40. The method of claim 37 wherein the control information comprises beam forming feedback for a high rate physical layer which comprises 2-bit phase information for 36 transmit antennas.

41. The method of claim 37 wherein the control information comprises beam forming feedback for a high rate physical layer which comprises 3-bit phase information for 24 transmit antennas.

42. The method of claim 37 wherein the control information comprises beam forming feedback for a high rate physical layer which comprises 4-bit phase information for 18 transmit antennas.

43. The method of claim 37 wherein the control information comprises beam forming feedback for a high rate physical layer which comprises 3-bit phase information and 3-bit magnitude information for 12 transmit antennas.

44. The method of claim 37 wherein the control information comprises beam forming feedback for a low rate physical layer which comprises 4-bit phase and 5-bit magnitude information for 8 transmit antennas.

45. The method of claim 37 wherein the control information comprises beam forming feedback for high and low rate physical layers that use gray-coded mapping.

46. The method of claim 37 wherein the 12 transmit antennas are sectorized antennas, and the magnitude feedback values are used to select one or more sectors to select.

47. A method comprising:

generating a modulated analog signal to send, via a wireless communication channel, wherein generating the modulated analog signal further comprises

using a high rate channel from a transmitter to a receiver in which a high rate physical layer circuit is operable to support up to 64 transmit antenna elements coupled to the RF transmitter.

48. The method of claim 47 wherein the high rate physical layer circuit is operable to produce data rates in the order of gigabits per second, and the low rate physical layer circuit is operable to produce data rates in the order of megabits per second.

49. The method of claim 47 further comprising first and second digital baseband processing units cooperating to perform adaptive beam steering by

performing adaptive beam forming that includes a beam search process to identify a beam direction;

and

performing a beam tracking process to track the beam during a data transfer phase.

50. The method of claim 47 further comprising estimating a transmitter antenna-array weight vector and a receiver antenna-array weight vector at the receiver.

51. The method of claim 47 further comprising setting the receive weight vector while estimating the transmitter antenna-array weight vector and setting the transmit weight vector while estimating the receiver antenna-array weight vector.

52. The method of claim 47 further comprising first and second digital baseband processing units cooperating to perform a beam search and adaptive beam steering by using a set of operations performed iteratively, the set of operations including

(a) the second digital baseband processing unit setting receive phase shifts for receive antennas of the second phased array antenna based on a first weight vector;

(b) the second digital baseband processing unit causing channel gains corresponding to each phase to be sequentially measured and forming a first set of channel gains;

(c) the second digital baseband processing unit calculating a second weight vector based on the first set of channel gains;

(d) the first digital baseband processing unit setting transmit phase shifts for transmit antennas of the first phased array antenna based on the second weight vector;

(e) the second digital baseband processing unit causing channel gains corresponding to each phase to be measured at the receiver and forming a second set of channel gains; and

(f) the second digital baseband processing unit calculating a third weight vector based on the second set of measured channel gains.

53. The method of claim 52 wherein the second digital baseband processing unit estimates the transmitter antenna weight vector by estimating channel vector elements one at a time, wherein a number of sequential estimation slots is set to 64.

54. The method of claim 52 wherein the second digital baseband processing unit estimates the transmitter antenna weight vector by using a 64-by-64 Hadamard-type matrix as a transfer matrix, such that transmit antenna weight vector is set to columns of the Hadamard-type matrix.

55. The method of claim 52 wherein the set of operations further comprises the second digital baseband processing unit using the third weight vector in place of the first weight vector when setting receive phase shifts for the receive antennas for a next iteration, and then repeating operations (a) through (f).

56. The method of claim 52 wherein the set of operations is performed for three iterations.

57. The method of claim 52 further comprising first and second digital baseband processing units cooperating to perform timing recovery prior to iteratively performing the set of operations.

58. The method of claim 52 further comprising first and second digital baseband processing units cooperating to perform delay estimation prior to iteratively performing the set of operations to determine an arrival time of a beam with maximum gain.

59. The method of claim 47 further comprising first and second digital baseband processing units cooperating to perform delay estimation by:

the first digital baseband processing unit causing the first phased array antenna to transmit a known symbol sequence over the air; and

the second digital baseband processing unit causing the known symbol sequence to be matched at the receiver via a matched filter.

63. The method of claim 47 further comprising repeating a transmitter antenna weight vector that produces the strongest received signal at the receiver more than once during the sequential estimation of the transmitter antenna weight vector.

64. The method of claim 47 further comprising a second digital baseband processing unit sending an index of the transmit weight vector that produced the strongest received signal at the receiver during the sequential estimation of the transmitter antenna weight vector, from the receiver to the transmitter using the back channel.