Construction of an interference matrix for a coded signal processing engine

• US 20040052305A1
• Filed: 11/15/2002
• Published: 03/18/2004
• Est. Priority Date: 11/16/2001
• Status: Active Grant

• Current Assignee: III Holdings 1, LLC (Intellectual Ventures LLC)
• Original Assignee: TensorComm, Inc. (Rambus Inc.)
• Inventors: Thomas, John K., Olson, Eric S.
• Granted Patent: US 7,200,183 B2
• Time in Patent Office: Days
• US Class Current: 375/148
• CPC Class Codes: H04B 1/7105 Joint detection techniques, e.g. linear detectors
• CPC Class Codes: H04B 1/7107 Subtractive interference cancellation
• CPC Class Codes: H04B 1/7117 Selection, re-selection, allocation or re-allocation of paths to fingers, e.g. timing offset control of allocated fingers

Abstract

A novel method for generating an interference matrix S is disclosed. The method comprises the following steps: A) Determining the number of active channels N in a transmitter; B) Selecting the transmitter to be canceled and assigning the transmitters sequentially to the variable t; C) Selecting the channel to be cancelled and assigning the channels sequentially to the variable n, where n is less than or equal to N; D) Determining if a multipath signal should be canceled and assigning the multipaths of interest to the respective variable M; E) Generating a sequence of column vectors V; F) Repeating steps B, C, D, E, F and G for each column vector of interest; and G) Defining the S matrix as S=[V₁ V₂ . . . V_c] wherein the index denotes the column index c. In addition, an apparatus for generating the interference matrix is also disclosed.

Claims

1. A method for generating an interference matrix S, the method comprising the steps of:

A. Determining the number of active channels N in a transmitter;

B. Selecting the transmitter to be canceled and assigning said transmitters sequentially to the variable t;

C. Selecting the channel to be cancelled and assigning said channels sequentially to the variable n, where n is less than or equal to N;

D. Determining if a multipath signal should be canceled and assigning the multipaths of interest to the respective variable M;

E. Generating a sequence of column vectors V;

F. Repeating steps B, C, D, E, F and G for each column vector of interest; and

G. Defining said S matrix as S=[V₁ V₂ . . . V_c] wherein the index denotes the column index c.

2. The method recited in claim 1, further comprising the steps of:

E1. Determining the relative amplitude of an interference signal (θ

); and

E2. Multiplying an interference vector s by θ

to produce the vector s_p;

where

$V=s_p<br><br>{\underset{t}{\overset{\text{\hspace{1em}<br><br>}}{\sum <br><br>}}}_{{\sum <br><br>}_n}^{\underset{M}{\sum <br><br>}}=\underset{t}{\overset{\text{\hspace{1em}<br><br>}}{\sum <br><br>}}<br><br>\underset{n}{\overset{\text{\hspace{1em}<br><br>}}{\sum <br><br>}}<br><br>\underset{M}{\overset{\text{\hspace{1em}<br><br>}}{\sum <br><br>}}<br><br>s_p<br><br>t_n^M$

where s_pt⁰ represents the line of sight (LOS) interference signal from said channel to be cancelled of said transmitter to be cancelled and M>

0 representing the multipaths interference signals of interest.

3. The method recited in claim 1, wherein said sequence of column vectors of the form V=s_bt_0-i^0-M produced over the indices corresponding to channel number (0-i), multipath number (0-M) and transmitter number t where s_bt_i⁰ represents the line of sight (LOS) interference signal from said channel to be cancelled of said transmitter to be cancelled where the knowledge of bits is known and M>

0 representing the multipaths interference signals of interest.

4. The method recited in claim 1, wherein said sequence of column vectors of the form V=st_0-n^0-M produced over the indices corresponding to channel number (0-n), multipath number (0-M) and transmitter number t where st⁰ represents the line of sight (LOS) interference signal from said channel to be cancelled of said transmitter to be cancelled and M>

0 representing the multipaths interference signals of interest.

5. The method recited in claim 1, wherein said determining step is conducted by pre-selecting a value for n.

6. The method recited in claim 1, wherein n is dynamically selected based upon a system criterion.

7. The method recited in claim 6, wherein said system criterion is a threshold criterion.

8. The method recited in claim 6, wherein said system criterion is a subset based upon a ranking procedure.

9. The method recited in claim 1, wherein said selecting the transmitter step is conducted by pre-selecting a value for t.

10. The method recited in claim 9, wherein t=1, which represents a single transmitter.

11. The method recited in claim 1, wherein said selecting the transmitter step is conducted by dynamically selecting a value for t.

12. The method recited in claim 1, wherein the number of columns c in said S matrix is predetermined.

13. The method recited in claim 1, wherein the number of columns c in said S matrix is less than or equal to the total number of active channels in all transmitters t, LOS and multipath signals M.

14. The method recited in claim 1, wherein M is dynamically selected based upon a system criterion.

15. The method recited in claim 14, wherein said system criterion is a threshold criterion.

16. The method recited in claim 14, wherein said system criterion is a subset based upon a ranking procedure.

17. The method recited in claim 1, wherein M is pre-selected.

18. The method recited in claim 3, further comprising the step of determining the sign of a transmitted symbol in data to determine whether said symbol is used in the construction of said S matrix or said symbol'"'"'s inverse is used.

19. The method recited in claim 18, wherein said sign of the symbol is determined dynamically for each channel at the symbol rate.

20. The method recited in claim 18, wherein said step of determining the sign of a symbol in a channel comprises the following steps:

A. Receiving a data signal y and producing a reference signal x₀ with the appropriate code offset, phase and/or frequency;

B. Correlating said data signal y with the code used for channelization;

C. Determining the sign of the symbol via the correlation step; and

D. Utilizing said sign information to determine whether symbol used in the correlation is used in the construction of said S matrix or said symbol'"'"'s inverse is used.

21. The method recited in claim 20, wherein said at least one code used for channelization is a pilot reference signal.

22. The method recited in claim 20, wherein said correlation is conducted by a Fast Hadamard Transform (FHT).

23. The method recited in claim 20, wherein said correlation is conducted by a Fast Walsh Transform (FWT).

24. The method recited in claim 18, further comprising the step of determining if the power of a channel exceeds a predetermined threshold in order to determine whether to use said symbol in the construction of said S matrix.

25. The method recited in claim 24 wherein said predetermined threshold is based upon the synchronization channel.

26. The method recited in claim 18, wherein a predetermined number of traffic channels are used in the construction of said S matrix.

27. The method recited in claim 2, wherein said step of determining the relative amplitude of a symbol in a channel comprises the following steps:

A. Receiving a data signal y and producing a reference signal x₀ with the appropriate code offset, phase and/or frequency;

B. Correlating said data signal y with the symbol used for channelization;

C. Determining the relative amplitude, including sign, of the symbol via the correlation step;

D. Scaling each symbol with said relative amplitude, including sign; and

E. Utilizing said relative amplitude information, including sign, to determine whether the symbol used in the correlation is used in the construction of said S matrix.

28. The method recited in claim 27, wherein said at least one symbol used for channelization is a pilot reference signal.

29. The method recited in claim 27, wherein said correlation is conducted by a Fast Hadamard Transform (FHT).

30. The method recited in claim 27, wherein said correlation is conducted by a Fast Walsh Transform (FWT).

31. The method recited in claim 27, further comprising the step of determining if the power of a channel exceeds a predetermined threshold in order to determine whether to use said symbol in the construction of said S matrix.

32. The method recited in claim 31 wherein said predetermined threshold is based upon the synchronization channel.

33. The method recited in claim 27, wherein a predetermined number of traffic channels are used in the construction of said S matrix.

34. An apparatus for generating an interference matrix S, said apparatus comprising:

means for determining the number of active channels N in a transmitter;

means for electing the transmitter to be canceled and assigning said transmitters sequentially to the variable t;

means for selecting the channel to be cancelled and assigning said channels sequentially to the variable n, where n is less than or equal to N;

means for determining if a multipath signal should be canceled and assigning the multipaths of interest to the respective variable M; and

means for generating a sequence of column vectors V;

wherein said S matrix is defined as S=[V₁ V₂ . . . V_c] and wherein the index denotes the column index c.

35. A method for generating an interference matrix S, the method comprising the steps of:

A. Determining the number of active channels N in a transmitter;

B. Selecting the transmitters to be canceled and assigning said transmitters sequentially to the variable t;

C. Selecting the channels to be cancelled and assigning said channels sequentially to the variable n, where n is less than or equal to N;

D. Determining if a multipath signal should be canceled and assigning the multipaths of interest to the respective variable M;

E. Generating a sequence of column vectors of the form V=st_0-n^0-M where st⁰ represents the line of sight (LOS) interference signal from said channel to be cancelled of said transmitter to be cancelled and M>

O representing the multipaths interference signals of interest;

F. Repeating steps B, C, D and E for each column vector of interest over the channel subscript from 0 to n, over the multipath superscript from 0 to M and over the transmitter variable t; and

G. Defining said S matrix as S=[V, V₂ VC] wherein the index denotes the column index c.

36. The method recited in claim 35, wherein said determining step is conducted by pre-selecting a value for n.

37. The method recited in claim 35, wherein n is dynamically selected based upon a system criterion.

38. The method recited in claim 37, wherein said system criterion is a threshold criterion.

39. The method recited in claim 37, wherein said system criterion is a subset based upon a ranking procedure.

40. The method recited in claim 35, wherein said selecting the transmitter step is conducted by pre-selecting a value for t.

41. The method recited in claim 38, wherein t=1, which represents a single transmitter.

42. The method recited in claim 35, wherein said selecting the transmitter step is conducted by dynamically selecting a value for t.

43. The method recited in claim 35, wherein the number of columns c in said S matrix is predetermined.

44. The method recited in claim 35, wherein the number of columns c in said S matrix is less than or equal to the total number of active channels in all transmitters t, LOS and multipath signals M.

45. The method recited in claim 35, wherein M is dynamically selected based upon a system criterion.

46. The method recited in claim 45, wherein said system criterion is a threshold criterion.

47. The method recited in claim 45, wherein said system criterion is a subset based upon a ranking procedure.

48. The method recited in claim 35, wherein M is pre-selected.

49. An apparatus for generating an interference matrix S, said apparatus comprising:

means for determining the number of active channels N in a transmitter;

means for electing the transmitters to be canceled and assigning said transmitters sequentially to the variable t;

means for electing the channels to be cancelled and assigning said channels sequentially to the variable n, where n is less than or equal to N;

means for determining if a multipath signal should be canceled and assigning the multipaths of interest to the respective variable M; and

means for generating a sequence of column vectors of the form V=st_0-n^0-M where st⁰ represents the line of sight (LOS) interference signal from said channel to be cancelled of said transmitter to be cancelled and M>

0 representing the multipaths interference signals of interest;

wherein said S matrix is defined as S=[V₁ V₂ . . . V_c] and wherein the index denotes the column index c.

50. A method for generating an interference matrix S, the method comprising the steps of:

A. Determining the number of active channels N in a transmitter;

B. Selecting the transmitters to be canceled and assigning said transmitters sequentially to the variable t;

C. Selecting the channel to be cancelled and assigning said channels sequentially to the variable n, where n is less than or equal to N;

D. Determining if a multipath signal should be canceled and assigning the multipaths of interest to the respective variable M;

E. Generating a sequence of column vectors of the form V=s_bt_0-i^0-M where s_bt_i⁰ represents the line of sight (LOS) interference signal from said channel to be cancelled of said transmitter to be cancelled where the knowledge of bits is known and M>

0 representing the multipaths interference signals of interest;

F. Repeating steps B, C, D and E for each column vector of interest over the channel subscript from 0 to i, over the multipath superscript from 0 to M and over the transmitter variable t; and

G. Defining said S matrix as S=[V₁ V₂ . . . V_c] wherein the index denotes the column index c.

51. The method recited in claim 50, wherein said determining step is conducted by pre-selecting a value for n.

52. The method recited in claim 50, wherein n is dynamically selected based upon a system criterion.

53. The method recited in claim 52, wherein said system criterion is a threshold criterion.

54. The method recited in claim 52, wherein said system criterion is a subset based upon a ranking procedure.

55. The method recited in claim 50, wherein said selecting the transmitter step is conducted by pre-selecting a value for t.

56. The method recited in claim 53, wherein t=1, which represents a single transmitter.

57. The method recited in claim 50, wherein said selecting the transmitter step is conducted by dynamically selecting a value for t.

58. The method recited in claim 50, wherein the number of columns c in said S matrix is predetermined.

59. The method recited in claim 50, wherein the number of columns c in said S matrix is less than or equal to the total number of active channels in all transmitters t, LOS and multipath signals M.

60. The method recited in claim 50, wherein M is dynamically selected based upon a system criterion.

61. The method recited in claim 60, wherein said system criterion is a threshold criterion.

62. The method recited in claim 60, wherein said system criterion is a subset based upon a ranking procedure.

63. The method recited in claim 50, wherein M is pre-selected.

64. The method recited in claim 50, further comprising the step of determining the sign of a transmitted symbol in data to determine whether said symbol is used in the construction of said S matrix or said symbol'"'"'s inverse is used.

65. The method recited in claim 64, wherein said sign of the symbol is determined dynamically for each channel at the symbol rate.

66. The method recited in claim 64, wherein said step of determining the sign of a symbol in a channel comprises the following steps:

A. Receiving a data signal y and producing a reference signal x₀ with the appropriate code offset, phase and/or frequency;

B. Correlating said data signal y with the code used for channelization;

C. Determining the sign of the symbol from the correlation step; and

D. Utilizing said sign information to determine whether symbol used in the correlation is used in the construction of said S matrix or said symbol'"'"'s inverse is used.

67. The method recited in claim 66, wherein said at least one code used for channelization is a pilot reference signal.

68. The method recited in claim 66, wherein said correlation is conducted by a Fast Hadamard Transform (FHT).

69. The method recited in claim 66, wherein said correlation is conducted by a Fast Walsh Transform (FWT).

70. The method recited in claim 64, further comprising the step of determining if the power of a channel exceeds a predetermined threshold in order to determine whether to use said symbol in the construction of said S matrix.

71. The method recited in claim 70, wherein said predetermined threshold is based upon the synchronization channel.

72. The method recited in claim 64, wherein a predetermined number of traffic channels are used in the construction of said S matrix.

73. An apparatus for generating an interference matrix S, said apparatus comprising:

means for determining the number of active channels N in a transmitter;

means for selecting the transmitters to be canceled and assigning said transmitters sequentially to the variable t;

means for selecting the channel to be cancelled and assigning said channels sequentially to the variable n, where n is less than or equal to N;

means for determining if a multipath signal should be canceled and assigning the multipaths of interest to the respective variable M; and

means for generating a sequence of column vectors of the form V=s_bt_0-i^0-M where s_bt_0-i^0-M represents the line of sight (LOS) interference signal from said channel to be cancelled of said transmitter to be cancelled where the knowledge of bits is known and M>

0 representing the multipaths interference signals of interest;

wherein said S matrix is defined as S=[V₁ V₂ . . . V_c] and wherein the index denotes the column index c.

74. A method for generating an interference matrix S, the method comprising the steps of:

A. Determining the number of active channels N in a transmitter;

B. Selecting the transmitters to be canceled and assigning said transmitters sequentially to the variable t;

C. Selecting the channels to be cancelled and assigning said channels sequentially to the variable n, where n is less than or equal to N;

D. Determining if a multipath signal should be canceled and assigning the multipaths of interest to the respective variable M;

E. Determining the relative amplitude of the interference signal (θ

) corresponding to the channel, transmitter and multipath of interest;

F. Multiplying an interference vector s by 0 to produce the vector SP

G. Generating a column vector

$V=s_p<br><br>{\underset{t}{\overset{\text{\hspace{1em}<br><br>}}{\sum <br><br>}}}_{{\sum <br><br>}_n}^{\underset{M}{\sum <br><br>}}=\underset{t}{\overset{\text{\hspace{1em}<br><br>}}{\sum <br><br>}}<br><br>\underset{n}{\overset{\text{\hspace{1em}<br><br>}}{\sum <br><br>}}<br><br>\underset{M}{\overset{\text{\hspace{1em}<br><br>}}{\sum <br><br>}}<br><br>s_p<br><br>t_n^M$

where s_pt⁰ represents the line of sight (LOS) interference signal from said channel to be cancelled of said transmitter to be cancelled and M>

0 representing the multipaths interference signals of interest;

H. Repeating steps B, C, D, E, F and G for each column vector of interest over the channel subscript n, over the multipath superscript M and the transmitter index t; and

I. Defining said S matrix as S=[V₁ V₂ V . . . V_c] wherein the index denotes the column index c.

75. The method recited in claim 74, wherein said determining step is conducted by pre-selecting a value for n.

76. The method recited in claim 74, wherein n is dynamically selected based upon a system criterion.

77. The method recited in claim 76, wherein said system criterion is a threshold criterion.

78. The method recited in claim 76, wherein said system criterion is a subset based upon a ranking procedure.

79. The method recited in claim 74, wherein said selecting the transmitter step is conducted by pre-selecting a value for t.

80. The method recited in claim 79, wherein t=1, which represents a single transmitter.

81. The method recited in claim 74, wherein said selecting the transmitter step is conducted by dynamically selecting a value for t.

82. The method recited in claim 74, wherein the number of columns c in said S matrix is predetermined.

83. The method recited in claim 74, wherein the number of columns c in said S matrix is equal to 1.

84. The method recited in claim 74, wherein the number of columns in said S matrix is less than or equal to the total number of active channels in all transmitters t, LOS and multipath signals M.

85. The method recited in claim 74, wherein M is dynamically selected based upon a system criterion.

86. The method recited in claim 85, wherein said system criterion is a threshold criterion.

87. The method recited in claim 85, wherein said system criterion is a subset based upon a ranking procedure.

88. The method recited in claim 74, wherein M is pre-selected.

89. The method recited in claim 74, wherein said step of determining the relative amplitude of a symbol in a channel comprises the following steps:

A. Receiving a data signal y and producing a reference signal x₀ with the appropriate code offset, phase and/or frequency;

B. Correlating said data signal y with the code used for channelization;

C. Determining the relative amplitude, including sign, of the symbol from the correlation step;

D. Scaling each symbol with said relative amplitude, including sign; and

E. Utilizing said amplitude information to determine whether the symbol used in the correlation is used in the construction of said S matrix.

90. The method recited in claim 89, wherein said at least one symbol used for channelization is a pilot reference signal.

91. The method recited in claim 89, wherein said correlation is conducted by a Fast Hadamard Transform (FHT).

92. The method recited in claim 89, wherein said correlation is conducted by a Fast Walsh Transform (FWT).

93. The method recited in claim 89, further comprising the step of determining if the power of a channel exceeds a predetermined threshold in order to determine whether to use said symbol in the construction of said S matrix.

94. The method recited in claim 93, wherein said predetermined threshold is based upon the synchronization channel.

95. The method recited in claim 89, wherein a predetermined number of traffic channels are used in the construction of said S matrix.

96. An apparatus for generating an interference matrix S, said apparatus comprising:

means for determining the number of active channels N in a transmitter;

means for selecting the transmitters to be canceled and assigning said transmitters sequentially to the variable t;

means for selecting the channels to be cancelled and assigning said channels sequentially to the variable n, where n is less than or equal to N;

means for determining if a multipath signal should be canceled and assigning the multipaths of interest to the respective variable M;

means for determining the relative amplitude of the interference signal (θ

) corresponding to the channel, transmitter and multipath of interest;

means for multiplying an interference vector s by θ

to produce the vector s_p; and

means for generating a column vector