System and method for geograpically locating a cellular phone

• US 20060009233A1
• Filed: 07/09/2004
• Published: 01/12/2006
• Est. Priority Date: 07/09/2004
• Status: Active Grant

• Current Assignee: Inrix Incorporated
• Original Assignee: ITIS Global Services Limited
• Inventors: Lavee, Uri, Meltzer, Yochay, Feldman, Israel, Eshpar, Allon
• Granted Patent: US 7,620,402 B2
• Time in Patent Office: Days
• US Class Current: 455/456.100
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 36/322 by location data
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

According to an embodiment of the invention, there is disclosed a method for geographically locating a cellular phone. The method comprises: determining an effective cell-area for each of a first cell and a second cell in a cellular network; and determining a handover area within which the cellular phone is likely to be located when control of the cellular phone is transferred from the first cell to the second cell; wherein the determination of the handover area and the effective cell-area for each of the first cell and the second cell are made based on a topological relationship between the first cell and the second cell. Further related apparatus embodiments are also disclosed.

Claims

1. A method for geographically locating a cellular device, the method comprising:

determining an effective cell-area for each of a first cell and a second cell in a cellular network; and

determining a handover area within which the cellular device is likely to be located when control of the cellular device is transferred from the first cell to the second cell;

wherein the determination of the handover area and the effective cell-area for each of the first cell and the second cell are made based on a topological relationship between the first cell and the second cell.

2. A method according to claim 1, further comprising:

determining a penumbra area around a line of equal intensity of reception between the first cell and the second cell.

3. A method according to claim 1, wherein the cellular network comprises a first antenna for the first cell and a second antenna for the second cell, and wherein the topological relationship is determined from amongst a set of topological cases comprising:

a first topological case in which the first antenna and the second antenna are located at a common location;

a second topological case in which the first antenna and the second antenna are located at different locations, and in which the first cell and the second cell are oriented to face each other;

a third topological case in which the first antenna and the second antenna are located at different locations, and in which the first cell and the second cell do not overlap; and

a fourth topological case in which none of the first, second, and third topological cases are satisfied.

4. A method according to claim 3, further comprising, when the topological relationship is determined to be one of the first, second, or third topological cases, determining a penumbra area around a line of equal intensity of reception between the first cell and the second cell.

5. A method according to claim 2 or 4, further comprising:

determining a first cell potential handover area by intersecting the effective cell-area of the first cell with the penumbra area;

determining a second cell potential handover area by intersecting the effective cell-area of the second cell with the penumbra area; and

determining the handover area for transfer of control of the cellular device by forming the union of the first cell potential handover area and the second cell potential handover area.

6. A method according to claim 1, further comprising:

determining the handover area for transfer of control of the cellular device by intersecting the effective cell-area of the first cell with the effective cell-area of the second cell.

7. A method according to claim 3, further comprising, when the topological relationship is determined to be the fourth topological case, determining the handover area for transfer of control of the cellular device by intersecting the effective cell-area of the first cell with the effective cell-area of the second cell.

8. A method according to claim 1, wherein determining the effective cell-area comprises using cell identifier data.

9. A method according to claim 1, wherein determining the effective cell-area comprises using time advance data.

10. A method according to claim 1, wherein determining the effective cell-area comprises determining an effective radius of the first cell and the second cell.

11. A method according to claim 10, wherein, when a first antenna for the first cell and a second antenna for the second cell are located at a common location, the effective radius is determined as a radius of a sector-shaped cell.

12. A method according to claim 10, wherein, when a first antenna for the first cell and a second antenna for the second cell are not located at a common location, the effective radius is determined as the product of a distance between the first antenna and the second antenna and a constant factor based on the topological relationship between the first cell and the second cell.

13. A method according to claim 10, wherein determining the effective cell-area further comprises extending an edge of a sector-shaped cell.

14. A method according to claim 13, wherein extending the edge of the sector-shaped cell comprises, when a first antenna for the first cell is contained within the second cell, and when an angle β

formed by a line between the first antenna and a second antenna for the second cell and a sector limit line of the second cell, is less than a predetermined angle α

,

extending the second cell beyond the sector limit line.

15. A method according to claim 14, wherein the second cell is extended by a rectangular extension beyond the sector limit line.

16. A method according to claim 13, wherein extending the edge of the sector shaped cell comprises, when a first antenna, for the first cell, is outside the second cell, and when an inner angle formed between a sector limit line of the second cell and a line between the first antenna and a second antenna for the second cell, is greater than 180 degrees,

extending the second cell beyond the sector limit line.

17. A method according to claim 16, wherein the second cell is extended by a rectangular extension beyond the sector limit line.

18. A method according to claim 16, wherein the second cell is extended beyond two sector limit lines.

19. A method according to claim 18, wherein the second cell is extended by two rectangular extensions, and wherein the method further comprises extending the second cell by a triangular extension connecting the two rectangular extensions.

20. A method according to claim 2 or 4, wherein determining the penumbra area comprises:

determining the location of the line of equal intensity; and

determining a rectangular strip around the line of equal intensity.

21. A method according to claim 20, wherein determining the location of the line of equal intensity comprises, when a first antenna for the first cell and a second antenna for the second cell are located at a common location, determining the line of equal intensity as the bisector of an angle formed by a first azimuth for the first cell and a second azimuth for the second cell.

22. A method according to claim 20, wherein determining the line of equal intensity comprises forming a central perpendicular to a line connecting a first antenna for the first cell and a second antenna for the second cell.

23. A method according to claim 20, wherein the rectangular strip is of asymmetrical width about the line of equal intensity.

24. A method according to claim 23, wherein a width W₁ of a first rectangular strip between the line of equal intensity and a first strip limit proximal to a cell into which the cellular device is moving, is longer than a width W₂ of a second rectangular strip between the line of equal intensity and a second strip limit proximal to a cell out of which the cellular device is moving.

25. A method according to claim 1, further comprising:

generating vehicle traffic data based at least in part on the handover area.

26. A method according to claim 25, further comprising:

sampling data received from the cellular network to determine the handover area.

27. A method according to claim 26, further comprising:

sampling vehicle position data from a plurality of different mobile sensor sources to generate the vehicle traffic data.

28. A method according to claim 25, further comprising:

storing a pre-determined handover area for the first cell and the second cell in a database; and

consulting the database to determine the handover area when data is received from the cellular network relating to a handover between the first cell and the second cell.

29. A method according to claim 25, further comprising:

determining the handover area using an online sampler which responds to streaming data received from the cellular network.

30. A method for geographically locating a cellular device in a cellular network comprising a first antenna for a first cell and a second antenna for a second cell, the method comprising:

determining an effective radius R_i for each of a set of i different topological relationships between the first cell and the second cell;

determining an angle α

for which, when the first antenna is contained within the second cell, and when an angle β

formed by a line between the first antenna and the second antenna and a sector limit line of the second cell is less than the angle a, the second cell will be extended beyond the sector limit line;

determining a first extension width E₁ of a first rectangular extension added to a sector limit line of the second cell when the angle β

is less than the angle α

;

determining a second extension width E₂ of a second rectangular extension added to a sector limit line of the second cell when the first antenna is outside the second cell, and when an inner angle formed between a sector limit line of the second cell and a line between the first antenna and the second antenna, is greater than 180 degrees;

determining a first penumbra width W₁ of a first rectangular strip between a line of equal intensity of signal reception from the first antenna and the second antenna, and a first strip limit proximal to a cell into which the cellular device is moving;

determining a second penumbra width W₂ of a second rectangular strip between the line of equal intensity and a second strip limit proximal to a cell out of which the cellular device is moving; and

determining a handover area within which the cellular device is likely to be located when control of the cellular device is transferred from the first cell to the second cell, the determination of the handover area being based on at least a subset of the effective radii R_i, the angle α

, the first extension width E₁, the second extension width E₂, the first penumbra width W₁, and the second penumbra width W₂.

31. An apparatus for geographically locating a cellular device, the apparatus comprising:

an effective cell-area module for determining an effective cell-area for each of a first cell and a second cell in a cellular network; and

a handover area module for determining a handover area within which the cellular device is likely to be located when control of the cellular device is transferred from the first cell to the second cell;

wherein the determination of the handover area and the effective cell-area for each of the first cell and the second cell are made based on a topological relationship between the first cell and the second cell.

32. An apparatus according to claim 31, further comprising:

a penumbra area module for determining a penumbra area around a line of equal intensity of reception between the first cell and the second cell.

33. An apparatus according to claim 31, wherein the cellular network comprises a first antenna for the first cell and a second antenna for the second cell, and wherein the topological relationship is determined from amongst a set of topological cases comprising:

a first topological case in which the first antenna and the second antenna are located at a common location;

a second topological case in which the first antenna and the second antenna are located at different locations, and in which the first cell and the second cell are oriented to face each other;

a third topological case in which the first antenna and the second antenna are located at different locations, and in which the first cell and the second cell do not overlap; and

a fourth topological case in which none of the first, second, and third topological cases are satisfied.

34. An apparatus according to claim 33, wherein the penumbra area module comprises means for, when the topological relationship is determined to be one of the first, second, or third topological cases, determining a penumbra area around a line of equal intensity of reception between the first cell and the second cell.

35. An apparatus according to claim 32 or 34, wherein the handover area module comprises means for:

determining a first cell potential handover area by intersecting the effective cell-area of the first cell with the penumbra area;

determining a second cell potential handover area by intersecting the effective cell-area of the second cell with the penumbra area; and

determining the handover area for transfer of control of the cellular device by forming the union of the first cell potential handover area and the second cell potential handover area.

36. An apparatus according to claim 31, wherein the handover area module comprises means for determining the handover area for transfer of control of the cellular device by intersecting the effective cell-area of the first cell with the effective cell-area of the second cell.

37. An apparatus according to claim 33, wherein the handover area module comprises means for, when the topological relationship is determined to be the fourth topological case, determining the handover area for transfer of control of the cellular device by intersecting the effective cell-area of the first cell with the effective cell-area of the second cell.

38. An apparatus according to claim 31, wherein the effective cell-area module comprises means for using cell identifier data.

39. An apparatus according to claim 31, wherein the effective cell-area module comprises means for using time advance data.

40. An apparatus according to claim 31, wherein the effective cell-area module comprises means for determining an effective radius of the first cell and the second cell.

41. An apparatus according to claim 40, wherein the effective cell-area module comprises means for, when a first antenna for the first cell and a second antenna for the second cell are located at a common location, determining the effective radius as a radius of a sector-shaped cell.

42. An apparatus according to claim 40, wherein the effective cell-area module comprises means for, when a first antenna for the first cell and a second antenna for the second cell are not located at a common location, determining the effective radius as the product of a distance between the first antenna and the second antenna and a constant factor based on the topological relationship between the first cell and the second cell.

43. An apparatus according to claim 40, wherein the effective cell-area module comprises means for determining an extension of an edge of a sector-shaped cell.

44. An apparatus according to claim 43, wherein the effective cell-area module comprises means for determining an extension of an edge of a sector-shaped cell by:

determining whether a first antenna for the first cell is contained within the second cell, and whether an angle β

formed by a line between the first antenna and a second antenna for the second cell and a sector limit line of the second cell, is less than a predetermined angle α

; and

, if so,

extending the second cell beyond the sector limit line.

45. An apparatus according to claim 44, wherein the effective cell-area module comprises means for extending the second cell by a rectangular extension beyond the sector limit line.

46. An apparatus according to claim 43, wherein the effective cell-area module comprises means for determining an extension of an edge of a sector-shaped cell by:

determining whether a first antenna, for the first cell, is outside the second cell, and whether an inner angle formed between a sector limit line of the second cell and a line between the first antenna and a second antenna for the second cell, is greater than 180 degrees; and

, if so,

extending the second cell beyond the sector limit line.

47. An apparatus according to claim 46, wherein the effective cell-area module comprises means for extending the second cell by a rectangular extension beyond the sector limit line.

48. An apparatus according to claim 46, wherein the effective cell-area module comprises means for extending the second cell by rectangular extensions beyond two sector limit lines.

49. An apparatus according to claim 48, wherein the effective cell-area module comprises means for extending the second cell by a triangular extension connecting two rectangular extensions.

50. An apparatus according to claim 32 or 34, wherein the penumbra area module comprises means for:

determining the location of the line of equal intensity; and

determining a rectangular strip around the line of equal intensity.

51. An apparatus according to claim 50, wherein the means for determining the location of the line of equal intensity comprises means for, when a first antenna for the first cell and a second antenna for the second cell are located at a common location, determining the line of equal intensity as the bisector of an angle formed by a first azimuth for the first cell and a second azimuth for the second cell.

52. An apparatus according to claim 50, wherein the means for determining the line of equal intensity comprises means for forming a central perpendicular to a line connecting a first antenna for the first cell and a second antenna for the second cell.

53. An apparatus according to claim 50, wherein the rectangular strip is of asymmetrical width about the line of equal intensity.

54. An apparatus according to claim 53, wherein a width W₁ of a first rectangular strip between the line of equal intensity and a first strip limit proximal to a cell into which the cellular device is moving, is longer than a width W₂ of a second rectangular strip between the line of equal intensity and a second strip limit proximal to a cell out of which the cellular device is moving.

55. An apparatus according to claim 31, further comprising:

a sampler module of a vehicle traffic information system.

56. An apparatus according to claim 55, wherein the sampler module comprises a plurality of sampler sub-modules for sampling vehicle position data from a plurality of different mobile sensor sources.

57. An apparatus according to claim 55, further comprising:

a database for storing the handover area, wherein the handover area is pre-determined such that the database is capable of being consulted based on streaming data from the cellular network.

58. A method of geographically locating a cellular device by determining the area in which handover from a first cell to a second cell occurs, the method comprising:

modeling at least a portion of a cell reception area of said first cell and said second cell; and

defining a handover area comprising overlapping portions of said first and second cell areas.

59. A method according to claim 58, further comprising:

determining whether to extend the cell reception area based on predetermined criteria.

60. A method according to claim 59, wherein the predetermined criteria comprise criteria based on a relative orientation of the first cell and the second cell.

61. A method according to claim 59, wherein the predetermined criteria comprise criteria based on relative positions of the first cell and the second cell.

62. A method according to claim 58, wherein modeling the at least a portion of the cell reception area of the first cell and the second cell comprises using a pre-defined shape as an initial model of at least a portion of the cell reception area of at least one of the first cell and the second cell.

63. A method according to claim 62, wherein the pre-defined shape comprises a sector.

64. A method according to claim 62, wherein the pre-defined shape comprises a ring-sector.

65. A method according to claim 58, wherein defining the handover area comprises forming a polygon representing the handover area.

66. A method according to claim 58, wherein defining the handover area comprises forming a penumbra area shape around a line of equal intensity of reception between the first cell and the second cell.

67. A method according to claim 66, wherein the penumbra area shape comprises a polygon.

68. A method according to claim 67, wherein the penumbra area shape comprises a rectangle.

69. A method of monitoring traffic flow by determining successive locations of a plurality of cellular devices located in a plurality of vehicles, the method comprising:

repeatedly determining the location of at least some of the plurality of cellular devices; and

sampling the locations of the at least some of the cellular devices to determine a present picture of traffic flow;

wherein determining the location of a cellular device of the plurality comprises determining the area in which handover from a first cell to a second cell occurs, the handover determination being based on;

modeling at least a portion of a cell reception area of said first cell and said second cell; and

defining the handover area to comprise overlapping portions of said first and second cell areas.

70. A method according to claim 69, further comprising predicting future traffic conditions based on the present picture of traffic flow.

71. A method according to claim 69, wherein the handover determination is made by consulting a database of pre-determined handover areas for cell pairs, using handover data from a cellular network.

72. A method according to claim 69, wherein the handover determination is made online using streaming handover data from a cellular network.

73. A method according to claim 71 or 72, wherein the handover data comprises cell identifier data.

74. A method according to claim 71 or 72, wherein the handover data comprises time advance data.

75. An apparatus for geographically locating a cellular device by determining the area in which handover from a first cell to a second cell occurs, the apparatus comprising:

an effective cell-area module for modeling at least a portion of a cell reception area of said first cell and said second cell; and

a handover area module for defining a handover area comprising overlapping portions of said first and second cell areas.

76. An apparatus according to claim 75, wherein the effective cell-area module comprises means for determining whether to extend the cell reception area based on predetermined criteria.

77. An apparatus according to claim 76, wherein the predetermined criteria comprise criteria based on a relative orientation of the first cell and the second cell.

78. An apparatus according to claim 76, wherein the predetermined criteria comprise criteria based on relative positions of the first cell and the second cell.

79. An apparatus according to claim 75, wherein the effective cell-area module comprises means for modeling the at least a portion of the cell reception area of the first cell and the second cell using a pre-defined shape as an initial model of at least a portion of the cell reception area of at least one of the first cell and the second cell.

80. An apparatus according to claim 79, wherein the pre-defined shape comprises a sector.

81. An apparatus according to claim 79, wherein the pre-defined shape comprises a ring-sector.

82. An apparatus according to claim 75, wherein the handover area module comprises means for forming a polygon representing the handover area.

83. An apparatus according to claim 75, wherein the handover area module comprises means for forming a penumbra area shape around a line of equal intensity of reception between the first cell and the second cell.

84. An apparatus according to claim 83, wherein the penumbra area shape comprises a polygon.

85. An apparatus according to claim 84, wherein the penumbra area shape comprises a rectangle.

86. An apparatus for monitoring traffic flow by determining successive locations of a plurality of cellular devices located in a plurality of vehicles, the apparatus comprising:

a handover area module for defining a handover area comprising overlapping portions of a modeled cell reception area of at least a portion of each of a first cell and a second cell of a cellular network; and

a sampler module for sampling a set of repeated location determinations of at least some of the plurality of cellular devices, to determine a present picture of traffic flow, wherein each such location determination is based at least in part on the handover area defined by the handover area module for a given cellular device moving between a given first cell and second cell of the cellular network.

87. An apparatus according to claim 86, further comprising:

a predictor module for predicting future traffic conditions based on the present picture of traffic flow.

88. An apparatus according to claim 86, further comprising:

a handover area database comprising pre-determined handover areas for cell pairs.

89. An apparatus according to claim 88, wherein the handover area module is capable of consulting the handover area database using streaming handover data from the cellular network.

90. An apparatus according to claim 86, wherein the handover area module is capable of determining the handover area online based on streaming handover data from the cellular network.

91. An apparatus according to claim 89 or 90, wherein the handover data comprises cell identifier data.

92. An apparatus according to claim 89 or 90, wherein the handover data comprises time advance data.