Reduced interference through offset frequency partitioning

• US 5,430,761 A
• Filed: 05/27/1994
• Issued: 07/04/1995
• Est. Priority Date: 11/25/1991
• Status: Expired due to Term

• Current Assignee: Motorola Mobility, Inc. (Lenovo Group Ltd.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Kotzin, Michael D., Bruckert, Eugene J.
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US08/250,306
• Time in Patent Office: 403 Days
• Field of Search: 375/1, 380/34, 455/33.1, 455/34.1, 455/34.2, 455/54.1, 455/54.2, 455/50.1, 455/63, 455/67.3, 370/58.1, 370/60, 370/77, 370/91, 370/92, 370/93, 370/94.1, 370/95.1, 370/95.3
• US Class Current: 375/144
• CPC Class Codes: H04B 7/2643 using time-division multiple access [TDMA] H04B7/2615, H04B7/2618 take precedence
• CPC Class Codes: H04J 4/00 Combined time-division and frequency-division multiplex systems H04J13/00 takes precedence ; data transmission H04L5/26; telemetry G08C15/00
• CPC Class Codes: H04W 16/02 Resource partitioning among network components, e.g. reuse partitioning
• CPC Class Codes: H04W 16/12 Fixed resource partitioning

Abstract

A method of reducing interference within a cellular system (10) by partitioning a designated frequency spectrum within a service coverage area (.0.1, .0.2, or .0.3) into a first and at least second spectrum inclusive of the designated frequency spectrum, each with an associated power level, and offsetting the spectrums for each TDM frame under the control of an offset number unique to each TDM frame. Assignment of communication units to a spectrum and power level are based upon distance from the base site (as determined through signal strength measurements). The spectral content of spectrums in adjacent service coverage areas is adjusted to include non-coincidental frequencies.

Claims

1. A method of assigning communication resources within a cell of a cellular communication system, such method including the steps of:

A) grouping communication units based upon a signal metric indicative of distance from a base site of the cell;

B) assigning the grouped communication units to group subspectra that includes an at least one distal subspectrum reserved for distal communication units, which distal subspectrum is non-coincident with distal spectra of adjacent cells; and

, C) spectrally offsetting the group subspectra based, in part, upon an offset number.

2. The method as in claim 1 further including the step of measuring the signal characteristic.

3. The method as in claim 2 further including the step of determining the signal characteristic to be a signal quality factor.

4. The method as in claim 2 further including the step of determining the signal characteristic to be transmission delay.

5. The method as in claim 1 further including the step of defining the group subspectra to be mutually exclusive subspectra of an assigned frequency spectrum.

6. The method as in claim 1 wherein the step of spectrally offsetting the group spectra further includes the step of generating an offset number.

7. The method as in claim 6 wherein the step of generating an offset number further includes the step of multiplying an output of a means for generating an offset number by a ratio determined by comparison of an allocated wideband channel to an allocated narrowband channel.

8. The method as in claim 1 further including the step of randomizing, within a group spectrum, an allocated baseband channel for a signal source.

9. The method as in claim 8 wherein the step of randomizing an allocated baseband channel further includes the step of referencing a look-up table for a randomizing number.

10. The method as in claim 8 wherein the step of randomizing an allocated baseband channel further includes the step of generating an subspectrum offset number as a randomizing number.

11. The method as in claim 1 further including the step of handing over a communication unit from one group spectrum to another.

12. The method as in claim 11 wherein the step of handing over a communication unit from one group spectrum further includes the step of determining a need for a handover based upon comparison of a signal characteristic of the communication unit with a threshold.

13. The method as in claim 12 wherein the step of determining a need for a handover based upon comparison of a signal characteristic of the communication unit with a threshold further includes the step of measuring the signal characteristics of the communication unit.

14. An apparatus for assigning communication resources within a cell of a cellular communication system, such apparatus comprising:

A) means for grouping communication units based upon a signal metric indicative of distance from a base site of the cell;

B) means for assigning the grouped communication units to group subspectra that includes an at least one distal subspectrum reserved for distal communication units, which distal subspectrum is non-coincident with distal spectra of adjacent cells; and

, C) means for spectrally offsetting the group subspectra based, in part, upon an offset number.

15. The apparatus as in claim 14 further comprising means for measuring the signal characteristic.

16. The apparatus as in claim 15 wherein the means for measuring the signal characteristic further comprises means for determining a signal quality factor.

17. The apparatus as in claim 15 wherein the means for measuring the signal characteristic further comprises means for determining a transmission delay.

18. The apparatus of claim 14 wherein the means for spectrally offsetting the group of spectra further comprises means for generating an offset number.

19. The apparatus as in claim 18 wherein the means for generating an offset number further comprises means for multiplying an output of a means for generating an offset number by a ratio determined by comparison of an allocated wideband channel to an allocated narrowband channel.

20. The apparatus as in claim 14 further comprising means for randomizing, within a group spectrum, an allocated baseband channel for a signal source.

21. The apparatus as in claim 20 wherein the means for randomizing an allocated baseband channel further comprises means for referencing a look-up table for a randomizing number.

22. The apparatus as in claim 20 wherein the means for randomizing an allocated baseband channel further comprises means for generating an subspectrum offset number as a randomizing number.

23. The apparatus as in claim 14 further comprising means for handing over a communication unit from one group spectrum to another.

24. The apparatus as in claim 23 wherein the means for handing over a communication unit from one group spectrum further comprises means for determining a need for a handover based upon comparison of a signal characteristic of the communication unit with a threshold.

25. The apparatus as in claim 24 wherein the means for determining a need for a handover based upon comparison of a signal characteristic of the communication unit with a threshold further comprises means for measuring the signal characteristics of the communication unit.

26. A method of reducing interference within a cellular system, such method including the steps of:

A) in one region;

1) allocating channels to radiotelephones having characteristic properties,

2) allocating other channels to radiotelephones not having the characteristic properties,

3) offsetting the allocated channels based, in part, upon an offset number,

B) in another potentially interfering region;

1) allocating the other channels to radiotelephones having characteristic properties,

2) allocating the channels to radiotelephones not having the characteristic properties,

3) offsetting the allocated channels based, in part, upon an offset number.

27. The method as in claim 26 wherein the step of offsetting the allocated channels further includes the step of generating an offset number.

28. The method as in claim 27 wherein the step of generating an offset number further includes the step of multiplying an output of a means for generating an offset number by a ratio determined by comparison of an allocated wideband channel to an allocated narrowband channel.

29. An apparatus for reducing interference within a cellular system, such apparatus comprising;

A) in one region;

1) means for allocating channels to radiotelephones having characteristic properties,

2) means for allocating other channels to radiotelephones not having the characteristic properties,

3) means for offsetting allocated channels based, in part, upon an offset number,

B) in another potentially interfering region;

1) means for allocating the other channels to radiotelephones having the characteristic properties

2) means for allocating the channels to radiotelephones not having the characteristic properties,

3) means for-offsetting the channel allocation based, in part, upon an offset number.

30. The apparatus of claim 29 wherein the means for offsetting the allocated channels further includes means for generating an offset number.

31. The apparatus as in claim 30, wherein the means for generating an offset number further includes means for multiplying an output of a means for generating an offset number by a ratio determined by comparison of an allocated wideband channel to an allocated narrowband channel.

32. A method of reducing interference within a cellular communication system having a plurality of base station sites, each upon occasion, providing communication services within a designated frequency spectrum to user communication units within a service coverage area of the base station site, such method including the step of:

A) partitioning the designated frequency spectrum into a first and an at least second spectrum inclusive of the designated frequency spectrum at a base station site;

B) receiving at the base station site a service request from a communication unit and measuring a signal characteristic of the service request;

C) allocating, by the base station site, a communication resource within the first spectrum to the communication unit when the measured signal characteristic exceeds a threshold and within the at least second spectrum to a communication unit when the measured signal characteristic does not exceed the threshold, and;

D) spectrally offsetting allocated resources based, in part, upon an offset number.

33. The method as in claim 32 further including the step of;

partitioning the designated frequency spectrum for an at least second spectrum serving adjacent locations in adjacent service coverage areas to substantially non-coincidental frequencies of the designated frequency spectrum.

34. The method as in claim 32 further including the step of;

performing secondary signal measurements of communication unit, communication transactions and maintaining signal quality by adjusting transmission power within a spectrum power range.

35. The method as in claim 32 wherein the step of partitioning the designated frequency spectrum further includes the step of adjusting the partitioning of the designated frequency spectrum based upon base station site loading.

36. The method as in claim 35 wherein the step of adjusting the partitioning further includes the step of calculating system loading based upon data contained within memory.

37. The method as in claim 32 wherein the step of spectrally offsetting the first and an at least second spectrum further includes the step of generating an offset number.

38. The method as in claim 37 wherein the step of generating an offset number further includes the step of multiplying an output of a means for generating an offset number by a ratio determined by comparison of an allocated wideband channel to an allocated narrowband channel.

39. The method as in claim 32 further including the step of randomizing, within the first and an at least second spectrum, the allocated resource for the communication unit.

40. The method as in claim 39 wherein the step of randomizing an allocated baseband channel further includes the step of referencing a look-up table for a randomizing number.

41. The method as in claim 39 wherein the step of randomizing an allocated baseband channel further includes the step of generating an subspectrum offset number as a randomizing number.

42. The method as in claim 32 further including the step of handing over the communication unit among the first and an at least second spectrum.

43. The method as in claim 42 wherein the step of handing over a signal source from one group spectrum further includes the step of determining a need for a handover based upon comparison of a signal characteristic of the communication unit with a threshold.

44. The method as in claim 43 wherein the step of determining a need for a handover based upon comparison of a signal characteristic of the communication unit with a threshold further includes the step of measuring the signal characteristics of the communication unit.

45. A device for reducing interference within a cellular communication system having a plurality of base station sites, each upon occasion, providing communication services within a designated frequency spectrum to user communication units within a service coverage area of the base station site, such device comprising:

A) means for partitioning the designated frequency spectrum into a first and an at least second spectrum inclusive of the designated frequency spectrum at the base station site;

B) means for receiving at the base station site a service request from a communication unit and measuring a signal characteristic of the service request;

C) means for allocating, by the base station site, a communication resource within the first spectrum to the communication unit when the measured signal characteristic exceeds a threshold and within the at least second spectrum to a communication unit when the measured signal characteristic does not exceed the threshold, and;

D) means for spectrally offsetting communication resources based, in part, upon an offset number.

46. The device as in claim 45 further comprising;

means for performing secondary signal measurements of communication unit, communication transactions and maintaining signal quality by adjusting transmission power within a spectrum power range.

47. The device as in claim 45 wherein the means for partitioning the designated frequency spectrum further comprising;

means for adjusting the partitioning of the designated frequency spectrum based upon base station site loading.

48. The device as in claim 47 wherein the means for adjusting the partitioning further comprising;

means for calculating system loading based upon data contained within memory.

49. The device as in claim 45 wherein the means for offsetting the first and an at least second spectrum further includes means for generating an offset number.

50. The device as in claim 49 wherein the means for generating an offset number further includes means for multiplying an output of a means for generating an offset number by a ratio determined by comparison of an allocated wideband channel to an allocated narrowband channel.

51. The device as in claim 45 further including the means for randomizing, within the first and an at least second spectrum, the allocated resource for the communication unit.

52. The device as in claim 51 wherein the means for randomizing an allocated baseband channel further includes means for referencing a look-up table for a randomizing number.

53. The device as in claim 51 wherein the means for randomizing an allocated baseband channel further includes means for generating an subspectrum offset number as a randomizing number.

54. The device as in claim 45 further including means for handing over the communication unit among the first and an at least second spectrum.

55. The device as in claim 54 wherein the means for handing over a signal source from one group spectrum further includes means for determining a need for a handover based upon comparison of a signal characteristic of the communication unit with a threshold.

56. The device as in claim 55 wherein the step of determining a need for a handover based upon comparison of a signal characteristic of the communication unit with a threshold further includes the step of measuring the signal characteristics of the communication unit.

57. A method of reducing interference within a cellular communication system having a plurality of base station sites, each upon occasion, providing communication services within a designated frequency spectrum to user communication units within a service coverage area of the base station site, such method including the steps of:

A) partitioning the designated frequency spectrum into a first and an at least second spectrum inclusive of the designated frequency spectrum at a base station site;

B) receiving at the base station site a service request from a communication unit and measuring a signal characteristic of the service request, and;

C) comparing the measured signal characteristic with an at least first threshold;

D) allocating, by the base station site, to the communication unit, a communication resource within a spectrum of the first and at least second spectrum based upon the relative magnitude of the measured signal characteristic, and;

E) spectrally offsetting the group spectrums based, in part, upon an offset number.

58. The method as in claim 57 further including the step of;

partitioning the designated frequency spectrum for an at least second spectrum serving adjacent locations in adjacent service coverage areas to substantially non-coincidental frequencies of the designated frequency spectrum.

59. The method as in claim 57 further including the step of;

performing secondary signal measurements of communication unit, communication transactions and maintaining signal quality by adjusting transmission power within a spectrum power range.

60. The method as in claim 57 wherein the step of partitioning the designated frequency spectrum further includes the step of adjusting the partitioning of the designated frequency spectrum based upon base station site loading.

61. The method as in claim 60 wherein the step of adjusting the partitioning further includes the step of calculating system loading based upon data contained within memory.

62. The method as in claim 57 wherein the step of spectrally offsetting the first and an at least second spectrum further includes the step of generating an offset number.

63. The method as in claim 57 wherein the step of generating an offset number further includes the step of multiplying an output of a means for generating an offset number by a ratio determined by comparison of an allocated wideband channel to an allocated narrowband channel.

64. The method as in claim 57 further including the step of randomizing, within the first and an at least second spectrum, an allocated baseband channel for a communication unit.

65. The method as in claim 64 wherein the step of randomizing an allocated baseband channel further includes the step of referencing a look-up table for a randomizing number.

66. The method as in claim 64 wherein the step of randomizing an allocated baseband channel further includes the step of generating an subspectrum offset number as a randomizing number.

67. The method as in claim 57 further including the step of handing over the communication unit among the first and an at least second spectrum.

68. The method as in claim 67 wherein the step of handing over a communication unit from one group spectrum further includes the step of determining a need for a handover based upon comparison of a signal characteristic of the communication unit with a threshold.

69. The method as in claim 68 wherein the step of determining a need for a handover based upon comparison of a signal characteristic of the signal source with a threshold further includes the step of measuring the signal characteristics of the communication unit.

70. A device reducing interference within a cellular communication system having a plurality of base station sites, each upon occasion, providing communication services within a designated frequency spectrum to user communication units within a service coverage area of the base station site, such device comprising:

A) means for partitioning the designated frequency spectrum into a first and an at least second spectrum inclusive of the designated frequency spectrum at a base station site;

B) means for receiving at the base station site a service request from a communication unit and measuring a metric of the service request, and;

C) means for comparing the measured metric with an at least first threshold;

D) means for allocating, by the base station site, to the communication unit, a communication resource within a spectrum of the first and at least second spectrum based upon a relative magnitude of the measured metric, and;

E) means for offsetting communication resources based upon an offset number.

71. The device as in claim 70 further comprising;

means for partitioning the designated frequency spectrum for an at least second spectrum serving adjacent locations in adjacent service coverage areas to substantially non-coincidental frequencies of the designated frequency spectrum.

72. The device as in claim 70 further comprising;

means for performing secondary signal measurements of communication unit, communication transactions and maintaining signal quality by adjusting transmission power within a spectrum power range.

73. The device as in claim 70 wherein the means for partitioning the designated frequency spectrum further comprising;

means for adjusting the partitioning of the designated frequency spectrum based upon base station site loading.

74. The device as in claim 73 wherein means for adjusting the partitioning further comprising;

means for calculating system loading based upon data contained within memory.

75. The device as in claim 70 wherein the means for offsetting the first and an at least second spectrum for each TDM frame further includes means for generating an offset number for each TDM frame.

76. The device as in claim 75 wherein the means for generating an offset number further includes means for multiplying an output of a means for generating an offset number by a ratio determined by comparison of an allocated wideband channel to an allocated narrowband channel.

77. The device as in claim 70 further including the means for randomizing, within the first and an at least second spectrum, an allocated baseband channel for a communication unit.

78. The device as in claim 77 wherein the means for randomizing an allocated baseband channel further includes means for referencing a look-up table for a randomizing number.

79. The device as in claim 77 wherein the means for randomizing an allocated baseband channel further includes means for generating an subspectrum offset number as a randomizing number.

80. The device as in claim 70 further including means for handing over the communication unit among the first and an at least second spectrum.

81. The device as in claim 80 wherein the means for handing over a communication unit from one group spectrum further includes means for determining a need for a handover based upon comparison of a signal characteristic of the signal source with a threshold.

82. The device as in claim 81 wherein the step of determining a need for a handover based upon comparison of a signal characteristic of the communication unit with a threshold further includes the step of measuring the signal characteristics of the communication unit.