Telecommunications – Radiotelephone system – Out-of-range indication
Patent
1997-09-15
2000-03-14
Chin, Wellington
Telecommunications
Radiotelephone system
Out-of-range indication
455440, 455441, 455457, 455517, 455566, 455575, H04Q 734
Patent
active
060384441
ABSTRACT:
Method and apparatus for tracking the location of, and for providing cellular telephone handoff for, a mobile cellphone user as the user moves from one cell to another. A boundary curve B12 between a first cell and an adjacent second cell is defined in an electronic map. First and second quasi-boundary curves QB1 and QB2, lying within the first and second cell, respectively, are defined, where each point on the curve QBi (i=1,2) lies at a selected distance from the boundary curve B12. A common region CR12 of points lying between the quasi-boundary curves QB1 and QB2 and including the boundary curve B12 is defined. The present cellphone location of the cellphone user is determined using a location determination system, such as GPS or GLONASS or a ground-based system. Cellular telephone service for the cellphone user is provided by a first cell site or by a second cell site, when the cellphone user is located within the first cell or the second cell, not including the overlap region CR12. When the cellphone user enters the region CR12 from within the first cell and proceeds toward the boundary curve B12, the user cellphone notifies at least one of the first and second cell sites that the cellphone user is about to leave the first cell and about to enter the second cell. The system advises the user if the cellphone is about to pass to another cell in which a cellular connection is likely to be dropped because no handoff cellular frequencies are available, or because the cellphone is about to enter a hole region where signal strength is less than an acceptable threshold value.
REFERENCES:
patent: 4463357 (1984-07-01), MacDoran
patent: 5432842 (1995-07-01), Kinoshita et al.
patent: 5471650 (1995-11-01), Vexler et al.
patent: 5483644 (1996-01-01), Moritz et al.
patent: 5546445 (1996-08-01), Dennison et al.
patent: 5551058 (1996-08-01), Hutcheson et al.
patent: 5551059 (1996-08-01), Hutcheson et al.
patent: 5557657 (1996-09-01), Barnett
patent: 5640676 (1997-06-01), Garncarz et al.
patent: 5809414 (1998-09-01), Coverdale et al.
Tom Logsdon, "The Navstar Global Positioning System," pp. 1-91, Van Nostrand Reinhold, 1992.
D.M. Balston and R.C.V. Macario, editors, "Cellular Radio Systems," chapters 1-2, and 6-7, pp. 3-72, and153-206, Artech House, 1993.
"Navstar GPS Space Segment/Navigation User Interfaces," Interface Control Document GPS(200), No. ICD-GPS-200, Rockwell International, Satellite Systems Division, Rev. B-PR, IRN-200B-PR-001, Apr. 16, 1993.
William C.Y. Lee, "Mobile Cellular Telecommunications Analog and Digital Systems," 2nd edition, pp. 53-71, McGraw-Hill, 1995.
Janky James M.
Najafi Hamid
Schipper John F.
Chin Wellington
Schipper John F.
Sobutka Philip J.
Trimble Navigation Limited
LandOfFree
Method and apparatus for advising cellphone users of possible ac does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for advising cellphone users of possible ac, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for advising cellphone users of possible ac will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-178190