SIGNALING METHOD IN AN OFDM MULTIPLE ACCESS SYSTEM

• US 20100195484A1
• Filed: 04/13/2010
• Published: 08/05/2010
• Est. Priority Date: 09/13/2000
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Uppala, Sathyadev Venkata, Laroia, Rajiv, Li, Junyi
• Granted Patent: US 7,990,844 B2
• Time in Patent Office: Days
• US Class Current: 370/208
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/26025 Numerology, i.e. varying one or more of symbol duration, subcarrier spacing, Fourier transform size, sampling rate or down-clocking allocating sub-channels of the transmission path H04L5/003
• CPC Class Codes: H04L 27/2614 Peak power aspects
• CPC Class Codes: H04L 27/2636 with FFT or DFT modulators, e.g. standard single-carrier frequency-division multiple access [SC-FDMA] transmitter or DFT spread orthogonal frequency division multiplexing [DFT-SOFDM]
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601

Abstract

A method for reducing the peak-to-average ratio in an OFDM communication signal is provided. The method includes defining a constellation having a plurality of symbols, defining a symbol duration for the OFDM communication signal, and defining a plurality of time instants in the symbol duration. A plurality of tones are allocated to a particular communication device, and a discrete signal is constructed in the time domain by mapping symbols from the constellation to the time instants. A continuous signal is generated by applying an interpolation function to the discrete signal such that the continuous signal only includes sinusoids having frequencies which are equal to the allocated tones.

Claims

1. An apparatus for generating a vector of digital signal samples (S), the apparatus comprising:

hardware means for receiving a discrete signal of complex data symbols (C), calculate frequency responses (A₁, . . . A_M) corresponding to tones (f₍₁₎, . . . f_(M)), through an M-point DFT, and output a vector of length M;

means for expanding the output vector to a new vector of length N, and means for inserting zero-value symbols corresponding to tones other than tones allocated to a transmitter; and

means for performing an N-point inverse discrete Fourier transform operation on the new vector after zero insertion to obtain the vector of digital signal samples (S), and generating a low peak-to-average OFDM-based signal using the vector of digital signal samples (S) for transmission.

2. The apparatus of claim 1, wherein the tones (f₍₁₎, . . . f_(M)) are allocated tones available for transmission.

3. The apparatus of claim 1, wherein the allocated tones are contiguous.

4. The apparatus of claim 1, wherein the vector of length N is larger than the vector of length M.

5. The apparatus of claim 1, wherein the allocated tones are equally spaced.

6. The apparatus of claim 2, wherein the allocated tones are contiguous.

7. The apparatus of claim 2, wherein the vector of length N is larger than the vector of length M.

8. The apparatus of claim 2, wherein the allocated tones are equally spaced.

9. The apparatus of claim 5, wherein the allocated tones are contiguous.

10. The apparatus of claim 5, wherein the vector of length N is larger than the vector of length M.

11. The apparatus of claim 9, wherein the vector of length N is larger than the vector of length M.

12. The apparatus of claim 6, wherein the vector of length N is larger than the vector of length M.

13. The apparatus of claim 12, wherein the allocated tones are equally spaced.

14. The apparatus of claim 7, wherein the allocated tones are equally spaced.

15. The apparatus of claim 7, wherein the allocated tones are contiguous.

16. The apparatus of claim 8, wherein the allocated tones are contiguous.

17. An apparatus for generating a vector of digital signal samples (S), the apparatus comprising:

hardware means for receiving a discrete signal of complex data symbols (C), calculate frequency responses (A₁, . . . A_M) corresponding to tones (f₍₁₎, . . . f_(M)), through an M-point DFT, and output a vector of length M;

hardware means for expanding the output vector to a new vector of length N, and means for inserting zero-value symbols corresponding to tones other than tones allocated to a transmitter; and

means for performing an N-point inverse discrete Fourier transform operation on the new vector after zero insertion to obtain the vector of digital signal samples (S), and generating a low peak-to-average OFDM-based signal using the vector of digital signal samples (S) for transmission.

18. The apparatus of claim 17, wherein the tones (f₍₁₎, . . . f_(M)) are allocated tones available for transmission.

19. The apparatus of claim 17, wherein the allocated tones are contiguous.

20. The apparatus of claim 17, wherein the vector of length N is larger than the vector of length M.

21. The apparatus of claim 17, wherein the allocated tones are equally spaced.

22. The apparatus of claim 18, wherein the allocated tones are contiguous.

23. The apparatus of claim 18, wherein the vector of length N is larger than the vector of length M.

24. The apparatus of claim 18, wherein the allocated tones are equally spaced.

25. The apparatus of claim 21, wherein the allocated tones are contiguous.

26. The apparatus of claim 21, wherein the vector of length N is larger than the vector of length M.

27. The apparatus of claim 25, wherein the vector of length N is larger than the vector of length M.

28. The apparatus of claim 22, wherein the vector of length N is larger than the vector of length M.

29. The apparatus of claim 28, wherein the allocated tones are equally spaced.

30. The apparatus of claim 23, wherein the allocated tones are equally spaced.

31. The apparatus of claim 23, wherein the allocated tones are contiguous.

32. The apparatus of claim 24, wherein the allocated tones are contiguous.

33. An apparatus for generating a vector of digital signal samples (S), the apparatus comprising:

hardware means for receiving a discrete signal of complex data symbols (C), calculate frequency responses (A₁, . . . A_M) corresponding to tones (f₍₁₎, . . . f_(M)), through an M-point DFT, and output a vector of length M;

hardware means for expanding the output vector to a new vector of length N, and means for inserting zero-value symbols corresponding to tones other than tones allocated to a transmitter; and

hardware means for performing an N-point inverse discrete Fourier transform operation on the new vector after zero insertion to obtain the vector of digital signal samples (S), and generating a low peak-to-average OFDM-based signal using the vector of digital signal samples (S) for transmission.

34. The apparatus of claim 33, wherein the tones (f₍₁₎, . . . f_(M)) are allocated tones available for transmission.

35. The apparatus of claim 33, wherein the allocated tones are contiguous.

36. The apparatus of claim 33, wherein the vector of length N is larger than the vector of length M.

37. The apparatus of claim 33, wherein the allocated tones are equally spaced.

38. The apparatus of claim 34, wherein the allocated tones are contiguous.

39. The apparatus of claim 34, wherein the vector of length N is larger than the vector of length M.

40. The apparatus of claim 34, wherein the allocated tones are equally spaced.

41. The apparatus of claim 37, wherein the allocated tones are contiguous.

42. The apparatus of claim 37, wherein the vector of length N is larger than the vector of length M.

43. The apparatus of claim 41, wherein the vector of length N is larger than the vector of length M.

44. The apparatus of claim 38, wherein the vector of length N is larger than the vector of length M.

45. The apparatus of claim 44, wherein the allocated tones are equally spaced.

46. The apparatus of claim 39, wherein the allocated tones are equally spaced.

47. The apparatus of claim 39, wherein the allocated tones are contiguous.

48. The apparatus of claim 40, wherein the allocated tones are contiguous.

49. An apparatus for generating a vector of digital signal samples (S), the apparatus comprising:

hardware means for receiving a discrete signal of complex data symbols (C), calculate frequency responses (A₁, . . . A_M) corresponding to tones (f₍₁₎, . . . f_(M)), through an M-point DFT, and output a vector of length M;

means for expanding the output vector to a new vector of length N, and means for inserting zero-value symbols corresponding to tones other than tones allocated to a transmitter; and

hardware means for performing an N-point inverse discrete Fourier transform operation on the new vector after zero insertion to obtain the vector of digital signal samples (S), and generating a low peak-to-average OFDM-based signal using the vector of digital signal samples (S) for transmission.

50. The apparatus of claim 49, wherein the tones (f₍₁₎, . . . f_(M)) are allocated tones available for transmission.

51. The apparatus of claim 49, wherein the allocated tones are contiguous.

52. The apparatus of claim 49, wherein the vector of length N is larger than the vector of length M.

53. The apparatus of claim 49, wherein the allocated tones are equally spaced.

54. The apparatus of claim 50, wherein the allocated tones are contiguous.

55. The apparatus of claim 50, wherein the vector of length N is larger than the vector of length M.

56. The apparatus of claim 50, wherein the allocated tones are equally spaced.

57. The apparatus of claim 53, wherein the allocated tones are contiguous.

58. The apparatus of claim 53, wherein the vector of length N is larger than the vector of length M.

59. The apparatus of claim 57, wherein the vector of length N is larger than the vector of length M.

60. The apparatus of claim 54, wherein the vector of length N is larger than the vector of length M.

61. The apparatus of claim 60, wherein the allocated tones are equally spaced.

62. The apparatus of claim 55, wherein the allocated tones are equally spaced.

63. The apparatus of claim 55, wherein the allocated tones are contiguous.

64. The apparatus of claim 56, wherein the allocated tones are contiguous.

65. An apparatus for generating a vector of digital signal samples (S), the apparatus comprising:

means for receiving a discrete signal of complex data symbols (C), calculate frequency responses (A₁, . . . A_M) corresponding to tones (f₍₁₎, . . . f_(M)), through an M-point DFT, and output a vector of length M;

means for expanding the output vector to a new vector of length N, and means for inserting zero-value symbols corresponding to tones other than tones allocated to a transmitter; and

hardware means for performing an N-point inverse discrete Fourier transform operation on the new vector after zero insertion to obtain the vector of digital signal samples (S), and generating a low peak-to-average OFDM-based signal using the vector of digital signal samples (S) for transmission.

66. The apparatus of claim 65, wherein the tones (f₍₁₎, . . . f_(M)) are allocated tones available for transmission.

67. The apparatus of claim 65, wherein the allocated tones are contiguous.

68. The apparatus of claim 65, wherein the vector of length N is larger than the vector of length M.

69. The apparatus of claim 65, wherein the allocated tones are equally spaced.

70. The apparatus of claim 66, wherein the allocated tones are contiguous.

71. The apparatus of claim 66, wherein the vector of length N is larger than the vector of length M.

72. The apparatus of claim 66, wherein the allocated tones are equally spaced.

73. The apparatus of claim 69, wherein the allocated tones are contiguous.

74. The apparatus of claim 69, wherein the vector of length N is larger than the vector of length M.

75. The apparatus of claim 73, wherein the vector of length N is larger than the vector of length M.

76. The apparatus of claim 70, wherein the vector of length N is larger than the vector of length M.

77. The apparatus of claim 76, wherein the allocated tones are equally spaced.

78. The apparatus of claim 71, wherein the allocated tones are equally spaced.

79. The apparatus of claim 71, wherein the allocated tones are contiguous.

80. The apparatus of claim 72, wherein the allocated tones are contiguous.

81. An apparatus for generating a vector of digital signal samples (S), the apparatus comprising:

means for receiving a discrete signal of complex data symbols (C), calculate frequency responses (A₁, . . . A_M) corresponding to tones (f₍₁₎, . . . f_(M)), through an M-point DFT, and output a vector of length M;

hardware means for expanding the output vector to a new vector of length N, and means for inserting zero-value symbols corresponding to tones other than tones allocated to a transmitter; and

hardware means for performing an N-point inverse discrete Fourier transform operation on the new vector after zero insertion to obtain the vector of digital signal samples (S), and generating a low peak-to-average OFDM-based signal using the vector of digital signal samples (S) for transmission.

82. The apparatus of claim 81, wherein the tones (f₍₁₎, . . . f_(M)) are allocated tones available for transmission.

83. The apparatus of claim 81, wherein the allocated tones are contiguous.

84. The apparatus of claim 81, wherein the vector of length N is larger than the vector of length M.

85. The apparatus of claim 81, wherein the allocated tones are equally spaced.

86. The apparatus of claim 82, wherein the allocated tones are contiguous.

87. The apparatus of claim 82, wherein the vector of length N is larger than the vector of length M.

88. The apparatus of claim 82, wherein the allocated tones are equally spaced.

89. The apparatus of claim 85, wherein the allocated tones are contiguous.

90. The apparatus of claim 85, wherein the vector of length N is larger than the vector of length M.

91. The apparatus of claim 89, wherein the vector of length N is larger than the vector of length M.

92. The apparatus of claim 86, wherein the vector of length N is larger than the vector of length M.

93. The apparatus of claim 92, wherein the allocated tones are equally spaced.

94. The apparatus of claim 87, wherein the allocated tones are equally spaced.

95. The apparatus of claim 87, wherein the allocated tones are contiguous.

96. The apparatus of claim 88, wherein the allocated tones are contiguous.

97. An apparatus for generating a vector of digital signal samples (S), the apparatus comprising:

means for receiving a discrete signal of complex data symbols (C), calculate frequency responses (A₁, . . . A_M) corresponding to tones (f₍₁₎, . . . f_(M)), through an M-point DFT, and output a vector of length M;

hardware means for expanding the output vector to a new vector of length N, and means for inserting zero-value symbols corresponding to tones other than tones allocated to a transmitter; and

means for performing an N-point inverse discrete Fourier transform operation on the new vector after zero insertion to obtain the vector of digital signal samples (S), and generating a low peak-to-average OFDM-based signal using the vector of digital signal samples (S) for transmission.

98. The apparatus of claim 97, wherein the tones (f₍₁₎, . . . f_(M)) are allocated tones available for transmission.

99. The apparatus of claim 97, wherein the allocated tones are contiguous.

100. The apparatus of claim 97, wherein the vector of length N is larger than the vector of length M.

101. The apparatus of claim 97, wherein the allocated tones are equally spaced.

102. The apparatus of claim 98, wherein the allocated tones are contiguous.

103. The apparatus of claim 98, wherein the vector of length N is larger than the vector of length M.

104. The apparatus of claim 98, wherein the allocated tones are equally spaced.

105. The apparatus of claim 101, wherein the allocated tones are contiguous.

106. The apparatus of claim 101, wherein the vector of length N is larger than the vector of length M.

107. The apparatus of claim 105, wherein the vector of length N is larger than the vector of length M.

108. The apparatus of claim 102, wherein the vector of length N is larger than the vector of length M.

109. The apparatus of claim 108, wherein the allocated tones are equally spaced.

110. The apparatus of claim 103, wherein the allocated tones are equally spaced.

111. The apparatus of claim 103, wherein the allocated tones are contiguous.

112. The apparatus of claim 104, wherein the allocated tones are contiguous.

113. A method for generating a vector of digital signal samples (S), the method comprising:

receiving a discrete signal of complex data symbols (C), calculate frequency responses (A₁, . . . A_M) corresponding to tones (f₍₁₎, . . . f_(M)), through an M-point DFT, and output a vector [A₁, . . . A_M] of length M;

expanding the vector to a new vector of length N, and inserting zero-value symbols corresponding to tones other than tones allocated to a transmitter; and

performing an N-point inverse discrete Fourier transform operation on the new vector after zero insertion to obtain the vector of digital signal samples (S), and generating a low peak-to-average OFDM-based signal using the vector of digital signal samples (S) for transmission.

114. The method of claim 113, wherein expanding the vector comprises allocating the tones (f₍₁₎, . . . f_(M)) as tones available for transmission.

115. The method of claim 113, wherein allocating the tones comprises allocating tones contiguously.

116. The method of claim 113, wherein expanding the vector comprises expanding the vector of length N such that the vector of length N is larger than the vector of length M.

117. The method of claim 113, wherein allocating the tones comprises allocating tones that are equally spaced.

118. The method of claim 114, wherein allocating the tones comprises allocating tones contiguously.

119. The method of claim 114, wherein expanding the vector comprises expanding the vector of length N such that the vector of length N is larger than the vector of length M.

120. The method of claim 114, wherein allocating the tones comprises allocating tones that are equally spaced.

121. The method of claim 117, wherein allocating the tones comprises allocating tones contiguously.

122. The method of claim 117, wherein expanding the vector comprises expanding the vector of length N such that the vector of length N is larger than the vector of length M.

123. The method of claim 121, wherein expanding the vector comprises expanding the vector of length N such that the vector of length N is larger than the vector of length M.

124. The method of claim 118, wherein expanding the vector comprises expanding the vector of length N such that the vector of length N is larger than the vector of length M.

125. The method of claim 124, wherein allocating the tones comprises allocating tones that are equally spaced.

126. The method of claim 119, wherein allocating the tones comprises allocating tones that are equally spaced.

127. The method of claim 119, wherein allocating the tones comprises allocating tones contiguously.

128. The method of claim 120, wherein allocating the tones comprises allocating tones contiguously.