Method and apparatus for advising cellphone users of possible actions to avoid dropped calls
First Claim
1. A method for providing information on an imminent cellular phone handoff between cells for a mobile cellphone user, the method comprising the steps of:
- determining a present location vector and a present velocity vector of a cellphone used by a cellphone user;
identifying a first cell on a cell map in which the cellphone is presently located;
identifying a second cell that is adjacent to the first cell, where the first and second cell are separated by a cell boundary, and the cellphone will pass into the second cell if the cellphone velocity vector is unchanged;
when the cellphone location vector is within the first cell and the cellphone is engaged in a cellular communication, estimating a remaining time Δ
t1 before the cellphone will pass into the second cell, if the cellphone velocity vector is unchanged;
advising the cellphone user of the remaining time when the remaining time lies in a selected range of times, determining whether an unused cellular frequency pair is available within said second cell to provide servicing of said cellular communication in which said cellphone user is engaged;
advising said cellphone user if an unused cellular frequency pair is not available within said second cell to provide servicing of said cellular communication in which said cellphone user is engaged; and
advising said cellphone user of at least one alternative action that may be taken to avoid passing into said second cell, when an unused cellular frequency pair is not available within said second cell.
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0 Petitions
Accused Products
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.
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Citations
18 Claims
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1. A method for providing information on an imminent cellular phone handoff between cells for a mobile cellphone user, the method comprising the steps of:
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determining a present location vector and a present velocity vector of a cellphone used by a cellphone user; identifying a first cell on a cell map in which the cellphone is presently located; identifying a second cell that is adjacent to the first cell, where the first and second cell are separated by a cell boundary, and the cellphone will pass into the second cell if the cellphone velocity vector is unchanged; when the cellphone location vector is within the first cell and the cellphone is engaged in a cellular communication, estimating a remaining time Δ
t1 before the cellphone will pass into the second cell, if the cellphone velocity vector is unchanged;advising the cellphone user of the remaining time when the remaining time lies in a selected range of times, determining whether an unused cellular frequency pair is available within said second cell to provide servicing of said cellular communication in which said cellphone user is engaged; advising said cellphone user if an unused cellular frequency pair is not available within said second cell to provide servicing of said cellular communication in which said cellphone user is engaged; and advising said cellphone user of at least one alternative action that may be taken to avoid passing into said second cell, when an unused cellular frequency pair is not available within said second cell. - View Dependent Claims (2, 3, 4)
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5. A method for minimizing loss of a cellular connection within a cellzone, the method comprising the steps of:
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determining a present location vector and a present velocity vector of a cellphone used by a cellphone user; identifying a cell on a cell map in which the cellphone is presently located;
identifying a signal strength hole region within the cell within which signal strength of a cellular connection is below a selected signal strength threshold;using information on the present location vector and present velocity vector of the cellphone to determine whether the cellphone is likely to pass into the signal strength hole region, if the cellphone velocity vector is unchanged; when the cellphone is determined to be likely to pass into the signal strength hole region, determining the time remaining before this likelihood occurs and advising the cellphone user of this likelihood and of the estimated time remaining before this likelihood occurs; and advising said cellphone user of at least one alternative action that may be taken to avoid passing into said signal strength hole region, when said cellphone is determined to be likely to pass into said signal strength hole region. - View Dependent Claims (6, 7, 8, 9)
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10. Apparatus for providing information on an imminent cellular phone handoff between cells for a mobile cellphone user, the apparatus comprising:
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a location determination (LD) system that receives LD signals and determines a present location vector and a present velocity vector of a cellphone used by a cellphone user; and a computer that communicates with the LD system and that is programmed; to identify a first cell on a cell map in which the cellphone is presently located; to identify a second cell that is adjacent to the first cell, where the first and second cell are separated by a cell boundary, and the cellphone will pass into the second cell if the cellphone velocity vector is unchanged; when the cellphone location vector is within the first cell and the cellphone is engaged in a cellular communication, to estimate a remaining time Dtl before the cellphone will pass into the second cell, if the cellphone velocity vector is unchanged; to advise the cellphone user of the remaining time when the remaining time lies in a selected range of times; to determine whether an unused cellular frequency pair is available within said second cell to provide servicing of said cellular communication in which said cellphone user is engaged; to advise said cellphone user if an unused cellular frequency pair is not available within said second cell to provide servicing of said cellular communication in which said cellphone user is engaged; and to advise said cellphone user of at least one alternative action that may be taken to avoid passing into said second cell, when an unused cellular frequency pair is not available within said second cell. - View Dependent Claims (11, 12, 13)
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14. Apparatus for minimizing loss of a cellular connection within a cellzone, the apparatus comprising:
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a location determination (LD) system that receives LD signals and determines a present location vector and a present velocity vector of a cellphone used by a cellphone user; and a computer that communicates with the LD system and that is programmed; to identify a cell on a cell map in which the cellphone is presently located; to identify a signal strength hole region within the cell within which signal strength of a cellular connection is below a selected signal strength threshold; to use information on the present location vector and present velocity vector of the cellphone to determine whether the cellphone is likely to pass into the signal strength hole region, if the cellphone velocity vector is unchanged; when the cellphone is determined to be likely to pass into the signal strength hole region, to determine the time remaining before this likelihood occurs and advising the cellphone user of this likelihood and of the estimated time remaining before this likelihood occurs; and to advise said cellphone user of at least one alternative action that may be taken to avoid passing into said signal strength hole region, when said cellphone is determined to be likely to pass into said signal strength hole region. - View Dependent Claims (15, 16, 17, 18)
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Specification