Construction of an interference matrix for a coded signal processing engine

• US 7,200,183 B2
• Filed: 11/15/2002
• Issued: 04/03/2007
• Est. Priority Date: 11/16/2001
• Status: Active Grant

• Current Assignee: III Holdings 1, LLC
• Original Assignee: TensorComm, Inc. (Rambus Inc.)
• Inventors: Olson, Eric S., Thomas, John K.
• Primary Examiner(s): Tran, Khanh
• Assistant Examiner(s): Ahn, Sam K.
• Application Number:
  US10/294,834
• Publication Number:
  US 20040052305A1
• Time in Patent Office: 1,600 Days
• Field of Search: 375/285, 375/278, 375/346, 375/316, 375/216, 375/347, 375/229, 702/196, 705/520, 705/514, 455/63, 455/65, 370/342, 370/335, 370/320
• US Class Current: 375/285
• 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. Selecting at least one transmitter to be canceled and assigning said at least one transmitter to a variable t;

B. Selecting at least one channel to be cancelled and assigning said at least one channels to a variable n, where n is less than or equal to a number of active channels N;

C. Determining if a multipath signal should be canceled and assigning each of at least one multipath of interest to a variable M;

D. Generating a sequence of column vectors V;

E. Repeating steps C and D for each of the column vectors V;

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

G. Determining a relative amplitude of an interference signal (θ

); and

H. Multiplying an interference vector s by θ

to produce a vector s_p;

where

$V=s_p<br><br>{\underset{t}{\overset{}{\sum <br><br>}}}_{{\sum <br><br>}_n}^{\underset{M}{\sum <br><br>}}=\underset{t}{\overset{}{\sum <br><br>}}<br><br>\underset{n}{\overset{}{\sum <br><br>}}<br><br>\underset{M}{\overset{}{\sum <br><br>}}<br><br>s_p<br><br>t_n^M,$

 

s_pt⁰ represents a line of sight (LOS) interference signal from said at least one channel to be cancelled of said at least one transmitter to be cancelled, and M>

0 represents multipaths of interference signals of interest.

2. 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 at least one channel to be cancelled of said at least one transmitter to be cancelled wherein transmitted bit values are known, and M>

0 represents multipaths of interference signals of interest.

3. The method recited in claim 2, further comprising determining a sign of a transmitted symbol in data to determine whether said symbol is used in the construction of said interference matrix S or said symbol'"'"'s inverse is used.

4. The method recited in claim 3, wherein said sign of the symbol is determined dynamically for each channel at the symbol rate.

5. The method recited in claim 3, wherein said step of determining the sign of a symbol in a channel comprises the following steps:

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

Correlating said data signal y with a code used for channelization;

Determining the sign of the symbol via the correlating step; and

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

6. The method recited in claim 5, wherein said at least one code used for channelization is a pilot reference signal.

7. The method recited in claim 5, wherein said correlating is conducted by a Fast Hadamard Transform (FHT).

8. The method recited in claim 5, wherein said correlating is conducted by a Fast Walsh Transform (FWT).

9. The method recited in claim 5, wherein said step of determining the relative amplitude of a symbol in a channel comprises the following steps:

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

Correlating said data signal y with at least one code used for channelization;

Determining the relative amplitude, including sign, of the symbol via the correlating step;

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

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

10. The method recited in claim 9, wherein said at least one code used for channelization is a pilot reference signal.

11. The method recited in claim 9, wherein said correlating step is conducted by a Fast Hadamard Transform (FHT).

12. The method recited in claim 9, wherein said correlating step is conducted by a Fast Walsh Transform (FWT).

13. The method recited in claim 9, further comprising 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 interference matrix S.

14. The method recited in claim 13, wherein said predetermined threshold is based upon synchronization channel.

15. The method recited in claim 9, wherein a predetermined number of traffic channels are used in the construction of said interference matrix S.

16. The method recited in claim 3, further comprising 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 interference matrix S.

17. The method recited in claim 3, wherein a predetermined number of traffic channels are used in the construction of said interference matrix S.

18. The method recited in claim 16, wherein said predetermined threshold is based upon the synchronization channel.

19. 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.

20. The method recited in claim 1, further comprising pre-selecting a value for n.

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

22. The method recited in claim 21, wherein said system criterion is a threshold criterion.

23. The method recited in claim 21, wherein said system criterion is a subset based upon a ranking procedure.

24. The method recited in claim 1, wherein said selecting at least one transmitter is conducted by pre-selecting a value for t.

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

26. The method recited in claim 1, wherein said selecting at least one transmitter is conducted by dynamically selecting a value for t.

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

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

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

30. The method recited in claim 29, wherein said system criterion is a threshold criterion.

31. The method recited in claim 29, wherein said system criterion is a subset based upon a ranking procedure.

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

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

means for determining a number of active channels N in a transmitted signal;

means for selecting at least one transmitter to be canceled and assigning each of said at least one transmitter to a variable t;

means for selecting at least one channel to be cancelled and assigning each of said at least one channel to a variable n, where n is less than or equal to N;

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

means for generating a sequence of column vectors V;

wherein said interference matrix S is defined as S=[V₁ V₂ . . . V_c], and wherein the index denotes a column index c, means for determining a relative amplitude of an interference signal (θ

); and

means for multiplying an interference vector s by θ

to produce a vector s_p;

where

$V=s_p<br><br>{\underset{t}{\overset{}{\sum <br><br>}}}_{{\sum <br><br>}_n}^{\underset{M}{\sum <br><br>}}=\underset{t}{\overset{}{\sum <br><br>}}<br><br>\underset{n}{\overset{}{\sum <br><br>}}<br><br>\underset{M}{\overset{}{\sum <br><br>}}<br><br>s_p<br><br>t_n^M,$

 

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

0 represents multipaths of interference signals of interest.

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

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

B. Selecting at least one transmitter to be canceled and assigning each of said at least one transmitter to a variable t;

C. Selecting at least one channel to be cancelled and assigning each of said at least one channel to a variable n, where n is less than or equal to N;

D. Determining if a multipath signal should be canceled and assigning at least one multipath of interest to a variable M;

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

0 represents multipaths of interference signals of interest;

F. Repeating steps B, C, D and E for each column vector of interest over channels 0 to n, over multipaths 0 to M, and over the variable t; and

G. Defining said interference matrix S as S=[V₁ V₂ . . . V_c], wherein subscript 1 to denotes a column index.

35. The method recited in claim 34, wherein said determining the number of active channels further comprises pre-selecting a value for n.

36. The method recited in claim 34, wherein n is dynamically selected based upon a system criterion.

37. The method recited in claim 36, wherein said system criterion is a threshold criterion.

38. The method recited in claim 37, wherein t=1, which represents a single transmitter.

39. The method recited in claim 36, wherein said system criterion is a subset based upon a ranking procedure.

40. The method recited in claim 34, wherein said selecting the at least one transmitter is conducted by pre-selecting a value for t.

41. The method recited in claim 34, wherein said selecting the at least one transmitter is conducted by dynamically selecting a value for t.

42. The method recited in claim 34, wherein the number of columns c in said interference matrix S is predetermined.

43. The method recited in claim 34, wherein the number of columns c in said interference matrix S is less than or equal to a total of the number of active channels in all transmitters t, LOS and multipath signals M.

44. The method recited in claim 34, wherein M is dynamically selected based upon a system criterion.

45. The method recited in claim 44, wherein said system criterion is a threshold criterion.

46. The method recited in claim 44, wherein said system criterion is a subset based upon a ranking procedure.

47. The method recited in claim 34, wherein M is pre-selected.

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

means for determining a number of active channels N in a transmitted signal;

means for selecting at least one transmitter to be canceled and assigning each of said at least one transmitter to a variable t;

means for selecting at least one channel to be cancelled and assigning each of said at least one channel to a variable n, where n is less than or equal to N;

means for determining if a multipath signal should be canceled and assigning each of at least one multipath of interest to variable M; and

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

0 representing multipaths of interference signals of interest;

wherein said interference matrix S is defined as S=[V₁ V₂ . . . V_c] and wherein subscripts 1 to c denote a column index.

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

A. Determining a number of active channels N in a transmitted signal;

B. Selecting at least one transmitter to be canceled and assigning each of said at least one transmitter to a variable t;

C. Selecting at least one channel to be cancelled and assigning each of said at least one channel to a variable n, where n is less than or equal to N;

D. Determining if a multipath signal should be canceled and assigning each of at least one multipath of interest to a variable M;

E. Generating a sequence of column vectors of the form V=S_bt_0-i^0-M, where S_bt_i⁰ represents a line of sight (LOS) interference signal from said at least one channel to be cancelled of said at least one transmitter to be cancelled, where transmitted bit values are known and M>

0 represents multipaths of interference signals of interest;

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

G. Defining said interference matrix S as S=[V₁ V₂ . . . V_c] wherein subscript 1 to c denotes a column index.

50. The method recited in claim 49, wherein said determining the number of active channels further comprises pre-selecting a value for n.

51. The method recited in claim 49, wherein n is dynamically selected based upon a system criterion.

52. The method recited in claim 51, wherein said system criterion is a threshold criterion.

53. The method recited in claim 52, wherein t=1, which represents a single transmitter.

54. The method recited in claim 51 wherein said system criterion is a subset based upon a ranking procedure.

55. The method recited in claim 49, wherein said selecting the at least one transmitter further comprises pre-selecting a value for t.

56. The method recited in claim 49, wherein said selecting the transmitter at least one is conducted by dynamically selecting a value for t.

57. The method recited in claim 49, wherein the number of columns c in said interference matrix S is predetermined.

58. The method recited in claim 49, wherein the number of columns c in said interference matrix S is less than or equal to a total of the number of active channels in all transmitters t, LOS and multipath signals M.

59. The method recited in claim 49, wherein M is dynamically selected based upon a system criterion.

60. The method recited in claim 59, wherein said system criterion is a threshold criterion.

61. The method recited in claim 59, wherein said system criterion is a subset based upon a ranking procedure.

62. The method recited in claim 49, wherein M is pre-selected.

63. The method recited in claim 49, further comprising determining a sign of a transmitted symbol in data to determine whether said symbol is used in the construction of said interference matrix S or said symbol'"'"'s inverse is used.

64. The method recited in claim 63, wherein said sign is determined dynamically for each channel at the symbol rate.

65. The method recited in claim 63, wherein said step of determining the sign of a symbol in a channel comprises the following steps:

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

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

Determining the sign of the symbol from the correlating step; and

Utilizing said sign to determine whether symbols used in the correlating step are to be used for constructing said interference matrix S or said symbol'"'"'s inverse is used.

66. The method recited in claim 65, wherein said at least one code used for channelization is a pilot reference signal.

67. The method recited in claim 65, wherein said correlating is conducted by a Fast Hadamard Transform (FHT).

68. The method recited in claim 65, wherein said correlating is conducted by a Fast Walsh Transform (FWT).

69. The method recited in claim 63, further comprising determining if the power of a channel exceeds a predetermined threshold in order to determine whether to use said symbol for constructing said interference matrix S.

70. The method recited in claim 69, wherein said predetermined threshold is based upon the synchronization channel.

71. The method recited in claim 63, wherein a predetermined number of traffic channels are used in the construction of said interference matrix S.

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

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

means for selecting at least one transmitter to be canceled and assigning said each of said at least one transmitter to a variable t;

means for selecting at least one channel to be cancelled and assigning each of said at least one channel to a variable n, where n is less than or equal to N;

means for determining if a multipath signal should be canceled and assigning at least one multipaths of interest to a variable M; and

means for generating a sequence of column vectors of the form V=S_bt_0-i^0-M where S_bt_i⁰ represents a line of sight (LOS) interference signal from said at least one channel to be cancelled of said at least one transmitter to be cancelled where transmitted bit values are known and M>

0 represents multipaths of interference signals of interest;

wherein said interference matrix S is defined as S=[V₁ V₂ . . . V_c], and wherein each of subscripts 1 to c denotes a column index.

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

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

B. Selecting at least one transmitter to be canceled and assigning each of said at least one transmitter to a variable t;

C. Selecting at least one channel to be cancelled and assigning said at least one channel to a variable n, where n is less than or equal to N;

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

E. Determining a relative amplitude of an interference signal (θ

) corresponding to the at least one channel, the at least one transmitter, and one of the plurality of multipaths of interest;

F. Multiplying an interference vector s by θ

to produce a vector s_p

G. Generating a column vector

$V=s_p<br><br>{\underset{t}{\overset{}{\sum <br><br>}}}_{{\sum <br><br>}_n}^{\underset{M}{\sum <br><br>}}=\underset{t}{\overset{}{\sum <br><br>}}<br><br>\underset{n}{\overset{}{\sum <br><br>}}<br><br>\underset{M}{\overset{}{\sum <br><br>}}<br><br>s_p<br><br>t_n^M,$

 

where s_pt⁰ represents a line of sight (LOS) interference signal from said at least one channel to be cancelled of said at least one transmitter to be cancelled, and M>

0 represents multipaths of interference signals of interest;

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

I. Defining said interference matrix S as S=[V₁ V₂ . . . V_c], wherein each of subscripts 1 to c denotes a column index.

74. The method recited in claim 73, wherein determining a number of active channels further comprises pre-selecting a value for n.

75. The method recited in claim 73, wherein n is dynamically selected based upon a system criterion.

76. The method recited in claim 75, wherein said system criterion is a threshold criterion.

77. The method recited in claim 75, wherein said system criterion is a subset based upon a ranking procedure.

78. The method recited in claim 73, wherein said selecting the at least one transmitter is conducted by pre-selecting a value for t.

79. The method recited in claim 78, wherein t=1, which represents a single transmitter.

80. The method recited in claim 73, wherein said selecting the at least one transmitter is conducted by dynamically selecting a value for t.

81. The method recited in claim 73, wherein the number of columns c in said interference matrix S is predetermined.

82. The method recited in claim 73, wherein the number of columns c in said interference matrix S is equal to 1.

83. The method recited in claim 73, wherein the number of columns in said interference matrix S is less than or equal to the total number of active channels in all transmitters t, LOS and multipath signals M.

84. The method recited in claim 73. wherein M is dynamically selected based upon a system criterion.

85. The method recited in claim 84, wherein said system criterion is a threshold criterion.

86. The method recited in claim 84, wherein said system criterion is a subset based upon a ranking procedure.

87. The method recited in claim 73, wherein M is pre-selected.

88. The method recited in claim 73, wherein said step of determining the relative amplitude of a symbol in a channel comprises:

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

Correlating said data signal y with at least one code used for channelization;

Determining the relative amplitude, including sign, of the symbol from the correlating step;

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

Utilizing said relative amplitude to determine whether the symbol used in the correlating is used for constructing said interference matrix S.

89. The method recited in claim 88, wherein said at least one code used for channelization is a pilot reference signal.

90. The method recited in claim 88, wherein said correlating is conducted by a Fast Hadamard Transform (FHT).

91. The method recited in claim 88, wherein said correlating is conducted by a Fast Walsh Transform (FWT).

92. The method recited in claim 88, further comprising the step of determining if power of a channel exceeds a predetermined threshold in order to determine whether to use said symbol in the construction of said interference matrix S.

93. The method recited in claim 92, wherein said predetermined threshold is based upon the synchronization channel.

94. The method recited in claim 88, wherein a predetermined number of traffic channels are used in the construction of said interference matrix S.

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

means for determining a number of active channels N in a transmitted signal;

means for selecting at least one transmitter to be canceled and assigning said at least one transmitter to a variable t;

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

means for determining if a multipath signal should be canceled and assigning at least one multipath of interest to a variable M;

means for determining a relative amplitude of an interference signal (θ

) corresponding to at least one channel, transmitter and multipath of interest;

means for multiplying an interference vector s by θ

to produce a vector s_p; and

means for generating a column vector

$V=s_p<br><br>{\underset{t}{\sum <br><br>}}_{{\sum <br><br>}_n<br><br>}^{{\sum <br><br>}_M}=<br><br>\underset{i}{\sum <br><br>}<br><br><br><br>\underset{n}{\sum <br><br>}<br><br><br><br>\underset{M}{\sum <br><br>}<br><br><br><br>s_p<br><br>t_n^M$

 

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

0 representing multipaths of interference signals of interest;

wherein said interference matrix S is defined as S=[V₁ V₂ . . . V_c] and wherein each of subscripts 1 to c denotes a column index.