System of and method for using position, velocity, or direction of motion estimates to support handover decisions
First Claim
1. A method of supporting a handover decision in a wireless communication system comprising:
- obtaining at least four time of arrival measurements for a subscriber station from at least four transmitting sources, wherein the at least four transmitting sources comprise known locations;
calculating initial x1, y1 and z1 coordinates and network time t1 for the subscriber station;
calculating a next x2, y2 and z2 coordinates and network time t2 for the subscriber station;
obtaining a velocity vector for an x component by (x2−
x1)/(t2−
t1), a y component by (y2−
y1)/(t2−
t1) and a z component by (z2−
z1)/(t2−
t1);
obtaining a magnitude of the vector by √
{square root over (x2 y2 z2)};
obtaining an estimate of position of the subscriber stations from the next x2, y2 and z2 coordinates, velocity of the subscriber station from the obtained magnitude of the vector and direction of motion of the subscriber station from a direction of the vector; and
using the estimate, or information derived there-from, to support the handover decision.
1 Assignment
0 Petitions
Accused Products
Abstract
A method of and system for supporting a handover decision in a wireless communication system is described. An estimate of the position, velocity or direction of motion of a subscriber station is obtained. The estimate, or information derived there-from, is then used to support a handover decision. In one embodiment, an estimate of the velocity of the subscriber station is obtained if the handover rate experienced by the subscriber station exceeds a threshold while the subscriber station is within the coverage area of an umbrella cell. A decision is made to handover the subscriber station to the umbrella cell if the estimate of the velocity of the subscriber station exceeds a threshold. In a second embodiment, one or more estimates of the position, velocity, or direction of motion of the subscriber station are obtained responsive to the subscriber station experiencing a directed retry condition. A decision is made to handover the subscriber station from a serving cell to a target cell if the one or more estimates indicate that (1) the subscriber station is located closer to the target cell than the serving cell; or (2) the subscriber station is moving towards the target cell and away from the serving cell.
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Citations
18 Claims
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1. A method of supporting a handover decision in a wireless communication system comprising:
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obtaining at least four time of arrival measurements for a subscriber station from at least four transmitting sources, wherein the at least four transmitting sources comprise known locations; calculating initial x1, y1 and z1 coordinates and network time t1 for the subscriber station; calculating a next x2, y2 and z2 coordinates and network time t2 for the subscriber station; obtaining a velocity vector for an x component by (x2−
x1)/(t2−
t1), a y component by (y2−
y1)/(t2−
t1) and a z component by (z2−
z1)/(t2−
t1);obtaining a magnitude of the vector by √
{square root over (x2 y2 z2)};obtaining an estimate of position of the subscriber stations from the next x2, y2 and z2 coordinates, velocity of the subscriber station from the obtained magnitude of the vector and direction of motion of the subscriber station from a direction of the vector; and using the estimate, or information derived there-from, to support the handover decision. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for supporting a handover decision in a wireless communication system, the system comprising:
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at least four transmitting sources for obtaining at least four time of arrival measurements for a subscriber station, wherein the at least four transmitting sources comprise known locations; a means for calculating initial X1, y1 and z1 coordinates and network time t1 for the subscriber station; a means for calculating a next x2, y2 and z2 coordinates and network time t2 for the subscriber station; means for obtaining a velocity vector for an x component by (x2−
x1)/(t2−
t1), a y component by (y2−
y1)/(t2−
t1) and a z component by (z2−
z1)/(t2−
t1);means for obtaining a magnitude of the vector by √
{square root over (x2 y2 z2)};means for obtaining an estimate of position of the subscriber stations from the next x2, y2 and z2 coordinates, velocity of the subscriber station from the obtained magnitude of the vector and direction of motion of the subscriber station from a direction of the vector; and the system for supporting comprising one or more entities configured to obtain the estimate of position, velocity or direction of motion of a subscriber station; and
use the estimate, or information derived there-from, to support the handover decision. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification
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- Resources
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Current AssigneeQualcomm, Inc.
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Original AssigneeQualcomm, Inc.
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InventorsJha, Anjali
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Primary Examiner(s)Feild; Joseph
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Assistant Examiner(s)DOAN, KIET M
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Application NumberUS10/632,400Publication NumberTime in Patent Office1,461 DaysField of Search455/456.1, 455/441, 455/67.11, 455/437, 455/440, 455/436, 455/574, 455/456.5, 455/450, 455/517, 455/11.1, 340/992, 342/457, 342/418US Class Current455/441CPC Class CodesH04W 36/322 by location dataH04W 36/324 by mobility data, e.g. spee...H04W 36/326 by proximity to another entityH04W 64/00 Locating users or terminals...
