Process and system for transferring vector signal with precoding for signal power reduction

• US 6,104,758 A
• Filed: 09/09/1997
• Issued: 08/15/2000
• Est. Priority Date: 04/01/1994
• Status: Expired due to Term

• Current Assignee: Conexant Systems Incorporated (Synaptics Incorporated)
• Original Assignee: Fujitsu Limited
• Inventors: Miyazawa, Hideo, Kaku, Takashi, Hirao, Kyoko
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): GHAYOUR, MOHAMMAD H
• Application Number:
  US08/925,181
• Time in Patent Office: 1,071 Days
• Field of Search: 375/265, 704/222, 704/256, 348/414, 348/417, 348/418
• US Class Current: 375/265
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 25/4975 Correlative coding using Tomlinson precoding, Harashima precoding, Trellis precoding or GPRS
• CPC Class Codes: H04L 27/34 Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
• CPC Class Codes: H04L 27/3411 reducing the peak to average power ratio or the mean power of the constellation; Arrangements for increasing the shape gain of a signal set

Abstract

A transfer process in which, an original vector signal is precoded to an intermediately-precoded vector signal, and the extended modulo operation is performed when the intermediately-precoded vector signal is located outside a predetermined extended-modulo limit area, and the precoded vector signal is transferred through a system having a predetermined filtering characteristic. From the transferred vector signal, the original vector signal is detected, based on a relationship between the vector components of the original vector signal and the transferred vector signal.

Claims

1. A transfer process comprising:

a plural-vector-signal generating step for generating a plurality of first vector signals in a vector space corresponding to an input vector signal, where each of said plurality of fist vector signals has first vector components and said input vector signal has second vector components;

an optimum vector signal selecting step for selecting an optimum one of the first vector signals;

a preceding step for precoding said optimum one of the first vector signals to generate a precoded vector signal;

a signal transferring step for transferring said precoded vector signal through a signal transferring system having a predetermined filtering characteristic which transforms said precoded vector signal into a transferred vector signal; and

a transferred vector signal determining step for receiving said transferred vector signal, and detecting said second vector components of said input vector signal from vector components of said transferred vector signal, based on a relationship between said vector components of said first vector signals and said vector components of said transferred vector signal.

2. A transfer process according to claim 1, wherein said signal transferring step comprises a filtering step for filtering said precoded vector signal before transferring said precoded-vector signal based on said predetermined filtering characteristic to transform said precoded vector signal into a filtered vector signal having substantially the same vector components of said transferred vector signal.

3. A transfer process according to claim 1, wherein said plurality of first vector signals corresponding to said input vector signal are said input vector signal and at least one additional vector signal located around a predetermined area in which said input vector signal is located.

4. A transfer process according to claim 3, wherein said at least one additional vector signal is located relatively far from the predetermined area when said input vector signal is located relatively far from the origin of the vector space, and said at least one additional vector signal is located relatively near the predetermined area when said input vector signal is located relatively near the origin of the vector space.

5. A transfer process according to claim 3, wherein said at least one additional vector signal is located relatively far from the predetermined area when said input vector signal is located relatively near the origin of the vector space, and said at least one additional vector signal is located relatively near the predetermined area when said input vector signal is located relatively far from the origin of the vector space.

6. A transfer process according to claim 1, wherein said plurality of first vector signals corresponding to the input vector signal are arranged uniformly spaced in the phase direction in the vector space.

7. A transfer process according to claim 1, wherein said optimum vector signal selecting step selects one of the first vector signals as said optimum one when it is determined that said one of the first vector signals is precoded to a precoded vector signal having smaller power than the powers of signals produced by precoding the other of said plurality of first vector signals.

8. A transfer process according to claim 1, further comprising, before said plural-vector-signals generating step, a control step for performing determination which one of said optimum one of the first vector signals and said input vector signal is to be precoded.

9. A transfer process according to claim 8, wherein said control step comprises a tentative preceding step for tentatively precoding said input vector signal to obtain a tentatively-precoded vector signal, a power obtaining step for tentatively obtaining the power of the tentatively-precoded vector signal, and a determining step for determining that said optimum one of the first vector signals is to be precoded to generate said precoded vector signal when the power of the tentatively-precoded vector signal exceeds a predetermined value, and determining that said input vector signal, instead of the optimum one of the first vector signals, is to be precoded to generate said precoded vector signal when the power of the tentatively-precoded vector signal does not exceed said predetermined value.

10. A transfer process according to claim 8, wherein said control step comprises a tentative precoded step for tentatively precoding said input vector signal to obtain a tentatively-precoded vector signal, a precoder tap power obtaining step for tentatively obtaining the power of the tentatively-precoded vector signal, an original power obtaining step for obtaining the power of the input vector signal, and a determining step for determining which one of said optimum one of the first vector signals and said input vector signal is to be precoded, based on the powers of the tentatively-precoded vector signal and the input vector signal.

11. A transfer process according to claim 1, wherein said signal transferring step contains a recording step for recording information represented by said precoded vector signal in a recording medium, and a reading step for reading the information recorded in the recording medium.

12. A transfer system comprising:

a plural-vector-signal generating unit for generating a plurality of first vector signals in a vector space corresponding to an input vector signal, where each of said plurality of first vector signals has first vector components and said input vector signal has second vector components;

an optimum vector signal selecting unit for selecting an optimum one of the first vector signals;

a precoding unit for precoding said optimum one of the first vector signals to generate a precoded vector signal;

a signal transferring system for transferring said precoded vector signal therethrough with a predetermined filtering characteristic which transforms said precoded vector signal into a transferred vector signal; and

a transferred vector signal determining unit for receiving said transferred vector signal, and detecting said second vector components of said input vector signal, based on a relationship between said vector components of said first vector signals and said vector components of said transferred vector signal.

13. A transfer system according to claim 12, wherein said signal transferring system comprises a filtering unit for filtering said precoded vector signal before transferring said precoded vector signal based on said predetermined filtering characteristic to transform said precoded vector signal into a filtered vector signal having substantially the same vector components of said transferred vector signal.

14. A transfer system according to claim 12, wherein said plurality of first vector signals corresponding to said input vector signal are said input vector signal and least one additional vector signal located around a predetermined area in which said input vector signal is located.

15. A transfer system according to claim 14, wherein said at least one additional vector signal is located relatively far from the predetermined area when said input vector signal is located relatively far from the origin of the vector space, and said at least one additional vector signal is located relatively near the predetermined area when said input vector signal is located relatively near the origin the vector space.

16. A transfer system according to claim 14, wherein said at least one additional vector signal is located relatively far from the predetermined area when said input vector signal is located relatively near the origin of the vector space, and said at least one additional vector signal is located relatively near the predetermined area when said input vector signal is located relatively far from the origin of the vector space.

17. A transfer system according to claim 12, wherein said plurality of first vector signals corresponding to the input vector signal are arranged uniformly spaced in the phase direction in the vector space.

18. A transfer system according to claim 12, wherein said optimum vector signal selecting unit selects one of the first vector signals as said optimum one when it is determined that said one of the first vector signals is precoded to a precoded vector signal having smaller power than the powers of signals produced by precoding the other of said plurality of first vector signals.

19. A transfer system according to claim 12, further comprising a control unit for performing determination which one of said optimum one of the optional vector signals and said input vector signal is to be precoded.

20. A transfer system according to claim 19, wherein said control unit comprises a tentative preceding unit for tentatively precoding said input vector signal to obtain a tentatively-precoded vector signal, a power obtaining unit for tentatively obtaining the power of the tentatively-precoded vector signal, and determining unit for determining that said optimum one of the first vector signals is to be precoded to generate said precoded vector signal when the power of the tentatively-precoded vector signal exceeds a predetermined value, and determining that said input vector signal, instead of the optimum one of the first vector signals, is to be precoded to generate said precoded vector signal when the power of the tentatively-precoded vector signal does not exceed said predetermined value.

21. A transfer system according to claim 19, wherein said control unit comprises a tentative precoding unit for tentatively preceding said input vector signal to obtain a tentatively-precoded vector signal, a precoder tap power obtaining unit for tentatively obtaining the power of the tentatively-precoded vector signal, an original power obtaining unit for obtaining the power of the input vector signal, and a determining unit for determining which one of said optimum one of the first vector signals and said input vector signal is to be precoded, based on the power of the tentatively-precoded vector signal and the input vector signal.

22. A transfer system according to claim 12, wherein said signal transferring system contains a signal recording medium, a vector signal recording mechanism for recording information represented by said precoded vector signal in the recording medium, and a signal reading mechanism for reading the information recorded in the recording medium.

23. A circuit comprising:

a plural-vector-signal generating unit for generating a plurality of first vector signals in a vector space corresponding to an input vector signal, where each of said plurality of first vector signals has first vector components and said input vector signal has second vector components;

an optimum vector signal selecting unit for selecting an optimum one of the first vector signals; and

a preceding unit for precoding said optimum one of the first vector signals to generate a precoded vector signal.

24. A circuit according to claim 23, further comprising a filtering unit for filtering said precoded vector signal based on said predetermined filtering characteristic to transform said preceded vector signal into a filtered vector signal having substantially the same vector components of said transferred vector signal.

25. A circuit according to claim 23, wherein said plurality of first vector signals corresponding to said input vector signal are said input vector signal and at least one additional vector signal located around a predetermined area in which said input vector signal is located.

26. A circuit according to claim 25, wherein said at least one additional vector signal is located relatively far from the predetermined area when said input vector signal is located relatively far from the origin of the vector space, and said at least one additional vector signal is located relatively near the predetermined area when said input vector signals is located relatively near the origin of the vector space.

27. A circuit according to claim 25, wherein said at least one additional vector signal is located relatively far from the predetermined area when said input vector signal is located relatively near the origin of the vector space, and said at least one additional vector signal is located relatively near the predetermined area when said input vector signal is located relatively far from the origin of the vector space.

28. A circuit according to claim 23, wherein said plurality of first vector signals corresponding to the input vector signal are arranged uniformly spaced in the phase direction in the vector space.

29. A circuit according to claim 23, further comprising a control unit for performing determination whether said preceding unit precodes said optimum one of the first vector signals or said input vector signal instead of the optimum one of the first vector signals, to generate said precoded vector signal, before performing the operation of said plural-vector-signal generating unit, and controlling the operation of the preceding unit in accordance with said determination.

30. A circuit according to claim 29, wherein said control unit comprises a tentative preceding unit for tentatively precoding said input vector signal to obtain a tentatively-precoded vector signal, a power obtaining unit for tentatively obtaining the power of the tentatively-precoded vector signal, and a determining unit for determining that said optimum one of the first vector signals is to be precoded to generate said precoded vector signal when the power of the tentatively-precoded vector signal exceeds a predetermined value, and determining that said input vector signal, instead of the optimum one of the first vector signals, is to be precoded to generate said precoded vector signal when the power of the tentatively-precoded vector signal does not exceed said predetermined value.

31. A circuit according to claim 29, wherein said control unit comprises a tentative precoding unit for tentatively precoding said input vector signal to obtain a tentatively-precoded vector signal, a precoder tap power obtaining unit for tentatively obtaining the power of the tentatively-precoded vector signal, an original power obtaining unit for obtaining the power of the input vector signal, and a determining unit for determining which one of said optimum one of the first vector signals and said input vector signal is to be precoded, based on the power of the tentatively-precoded vector signal and the input vector signal.

32. A data recording apparatus comprising:

a plural-vector-signal generating unit for generating a plurality of fist vector signals in a vector space corresponding to an input vector signal, where each of said plurality of first vector signals has first vector components and said input vector signal has second vector components;

an optimum vector signal selecting unit for selecting an optimum one of the first vector signals;

a preceding unit for preceding said optimum one of the fst vector signals to generate a precoded vector signal; and

a vector signal recording mechanism for recording information represented by said precoded vector signal in a recording medium.

33. A data recording apparatus according to claim 32, further comprising a filtering unit for filtering said precoded vector signal based on said predetermined filtering characteristic to transform said precoded vector signal into a filtered vector signal having substantially the same vector components of said transferred vector signal.

34. A data recording apparatus according to claim 32, wherein said plurality of first vector signals corresponding to said input vector signal are said input vector signal and at least one additional vector signal located around a predetermined area in which said input vector signal is located.

35. A data recording apparatus according to claim 34, wherein said at least one additional vector signal is located relatively far from the predetermined area when said input vector signal is located relatively far from the origin of the vector space, and said at least one additional vector signal is located relatively near the predetermined area when said input vector signal is located relatively near the origin of the vector space.

36. A data recording apparatus according to claim 34, wherein said at least one additional vector signal is located relatively far from the predetermined area when said input vector signal is located relatively near the origin of the vector space, and said at least one additional vector signal is located relatively near the predetermined area when said input vector signal is located relatively far from the origin of the vector space.

37. A data recording apparatus according to claim 32, wherein said plurality of first vector signals corresponding to the input vector signal are arranged uniformly spaced in the phase direction in the vector space.

38. A data recording apparatus according to claim 32, further comprising a control unit for performing determination which one of said optimum one of the first vector signals and said input vector signal is to be precoded.

39. A data recording apparatus according to claim 38, wherein said control unit comprises a tentative precoding unit for tentatively precoding said input vector signal to obtain a tentatively-precoded vector signal, a power obtaining unit for tentatively obtaining the power of the tentatively-precoded vector signal, and a determining unit for determining that said optimum one of the first vector signals is to be precoded to generate said precoded vector signal when the power of the tentatively-precoded vector signal exceeds a predetermined value, and determining that said preceding unit precodes input vector signal, instead of the optimum one of the first vector signals, is to be precoded to generate said precoded vector signal when the power of the tentatively-precoded vector signal does not exceed said predetermined value.

40. A data recording apparatus according to claim 38, wherein said control unit comprises a tentative precoding unit for tentatively precoding said input vector signal to obtain a tentatively-precoded vector signal, a precoder tap power obtaining unit for tentatively obtaining the power of the tentatively-precoded vector signal, an original power obtaining unit for obtaining the power of the input vector signal, and a determined unit for determining which one of said optimum one of the first vector signals and said input vector signal is to be precoded, based on the powers of the tentatively-precoded vector signal and the input vector signal.

41. A circuit comprising:

a transferred vector signal receiving unit for receiving a transferred vector signal having transferred vector components; and

an original vector signal determining unit for determining input vector components of an input vector signal from the transferred vector components of said transferred vector signal, based on a relationship between said transferred vector components of said transferred vector signal and the vector components of first vector signals, wherein

said relationship between the transferred vector components and the vector components of the first vector signals are predetermined to be equivalent to the relationship between the transferred vector components and the vector components of the first vector signals when the transferred vector components are generated from the input vector components through the following steps of,

(a) generating a plurality of first vector signals in a vector space corresponding to said input vector signal, where each of said plurality of first vector signals has first vector components,

(b) selecting an optimum one of the first vector signals,

(c) preceding said optimum one of the first vector signals to generate a precoded vector signal, and

(d) filtering said precoded vector signal based on a predetermined filtering characteristic to transform said precoded vector signal into said transferred vector signal.

42. A circuit according to claim 41, wherein said transferred vector receiving unit contains a vector signal reading mechanism for reading the information representing the first vector signal and being recorded in a recording medium.