Best server selection in layered cellular radio system
First Claim
1. A method of performing server selection for a mobile station operating within a cellular radio system comprised of multiple levels of cells having different service areas, said method comprising the steps of:
- assigning to each cell according to cell level a category of preference for selection with respect to each other associated cell within the system having either a coextensive, adjacent, contiguous, or overlapping service area;
assigning to each associated cell a preselected signal strength threshold;
measuring the signal strength of communications between the mobile station and each base station serving the associated cells;
comparing the measured signal strengths to the preselected thresholds for each of the associated cells; and
selecting for the mobile station as server a base station serving a candidate one of the associated cells based upon whether the measured signal strength to the candidate associated cell is greater than the preselected signal strength threshold assigned to said cell and whether the candidate associated cell has a higher category of preference than a currently serving cell.
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Accused Products
Abstract
A multi-level layered cellular radio architecture serves mobile subscriber stations moving within the system. Best server selection is performed for the mobile stations by assigning within each cell a preference value to each other one of the cells with which is associated by proximity of service area. The strength of the radio signal received by the mobile from the serving cell as well as the radio channels of associated cells is measured. A decision as to the best serving cell for the mobile station is made based upon both the preference value of the associated cells and the signal strength of their respective radio channels.
128 Citations
30 Claims
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1. A method of performing server selection for a mobile station operating within a cellular radio system comprised of multiple levels of cells having different service areas, said method comprising the steps of:
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assigning to each cell according to cell level a category of preference for selection with respect to each other associated cell within the system having either a coextensive, adjacent, contiguous, or overlapping service area; assigning to each associated cell a preselected signal strength threshold; measuring the signal strength of communications between the mobile station and each base station serving the associated cells; comparing the measured signal strengths to the preselected thresholds for each of the associated cells; and selecting for the mobile station as server a base station serving a candidate one of the associated cells based upon whether the measured signal strength to the candidate associated cell is greater than the preselected signal strength threshold assigned to said cell and whether the candidate associated cell has a higher category of preference than a currently serving cell. - View Dependent Claims (2, 3, 4)
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5. A method of performing best server selection for a mobile station operating within a cellular radio system comprised of multiple levels of cells each having a specific service area, said method comprising the steps of:
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assigning to each cell a category of preference with respect to each of the other cells within the system having either a coextensive, adjacent, contiguous, or overlapping service area, said categories of preference comprising a category of preferred, a category of equal preference or a category of non-preferred, said category assignment based upon the size of the cell'"'"'s service area relative to that of other cells; measuring the signal strength of communications between the mobile station and a first base station for a first cell currently selected as best server, and between the mobile station and a second base station for a second cell in the system; identifying the assigned category of preference for the second cell; selecting the second base station as the best server in response to satisfaction of any one of the following conditions, (a) the second cell having a category of preference of preferred and the measured signal strength with the second base station being greater than a preselected signal strength threshold, or (b) the second cell having a category of preference of equal preference and the measured signal strength with the second base station being greater than the measured signal strength with the first base station, or (c) the second cell having a category of preference of non-preferred and the measured signal strength with the first base station being less than a preselected signal strength threshold and the measured signal strength with the second base station being greater than that with the first base station. - View Dependent Claims (6, 8)
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7. A method of performing best server selection as set forth in claim 7 further comprising the steps of:
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measuring the signal strength of communications between the mobile station and each of the base stations serving associated ones of the cells in the system having either a coextensive, adjacent, contiguous, or overlapping service area; identifying the assigned category of preference for each of the associated cells; selecting as the base station best serving the mobile station that particular base station for One Of the associated cells satisfying any one of the following conditions, (a) the particular base station being in a cell having a category of preference of preferred and having a measured signal strength with the mobile station greater than a preselected signal strength threshold, or (b) the particular base station being in a cell having a category of preference of equal preference and having a measured signal strength with the mobile station greater than the measured signal strength between the mobile station and the first base station, or (c) the particular base station being in a cell having a category of preference of non-preferred and having a measured signal strength with the mobile station greater than the measured signal strength between the mobile station and the first base station and wherein the measured signal strength between the mobile station and the first base station is less than a preselected signal strength threshold.
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9. A system for performing server selection for a mobile station operating within a cellular radio system comprised of multiple levels of cells having different service areas, each cell assigned according to cell level a category of preference for selection with respect to each other associated cell within the system having either a coextensive, adjacent, contiguous, or overlapping service area, and for assigning to each associated cell a preselected signal strength threshold, said system comprising;
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means for measuring the signal strength of communications between the mobile station and each base station serving the associated cells; means connected to the means for measuring for comparing the measured signal strengths to the preselected signal strength thresholds for the associated cells; and means connected to the means for comparing for selecting for the mobile station as server a base station serving a candidate one of the associated cells based upon whether the measured signal strength to the candidate associated cell is greater than the preselected signal strength threshold for said cell and whether the candidate associated cell has a higher category of preference than a currently serving cell. - View Dependent Claims (10, 11, 12)
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13. A system for performing best server selection for a mobile station operating within a cellular radio system comprised of multiple levels of cells each having a different service area, each cell assigned a category of preference with respect to each of the other cells within the system having either a coextensive, adjacent, contiguous, or overlapping service area, said categories of preference comprising a category of preferred, a category of equal preference or a category of non-preferred, said category assignment based upon the size of its service area relative to that of other cells, said system comprising;
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means for measuring the signal strength of communications between the mobile station and a first base station for a first cell currently selected as best server, and between the mobile station and a second base station for a second cell in the system; means connected to the means for measuring for identifying the assigned category of preference for the second cell; means connected to the means for identifying for selecting the second base station as the best server in response to satisfaction of any one of the following conditions, (a) the second cell having a category of preference of preferred and the measured signal strength with the second base station being greater than a preselected signal strength threshold, or (b) the second cell having a category of preference of equal preference and the measured signal strength with the second base station being greater than the measured signal strength with the first base station, or (c) the second cell having a category of preference of non-preferred and the measured signal strength with the first base station being less than a preselected signal strength threshold and the measured signal strength with the second base station being greater than that with the first base station. - View Dependent Claims (14, 15, 16)
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17. A cellular communications system including a plurality of cells arranged in multiple layers, comprising:
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a base station for each of the plurality of cells, each base station assigned a category of preference for server selection with respect to each neighboring cell in the plurality of cells having either a coextensive, adjacent, contiguous, or overlapping service area, each base station further assigned a signal strength threshold for mobile station communications within the cell; and a plurality of mobile stations moving through the plurality of cells and communicating with the plurality of base stations, each mobile station comprising; means for measuring the signal strength of communications between the mobile station and each of the base stations within communications range; and processing means connected to the means for measuring for making a server selection determination for the mobile station based on a comparison of the measured signal strength of communications with each candidate base station to the assigned signal strength threshold for those candidate base stations in conjunction with a comparison of the category of preference assigned to each candidate base station. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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24. In a cellular communications system including a plurality of cells arranged in multiple layers, wherein each cell includes a base station, and further including a plurality of mobile stations moving through the plurality of cells and communicating with the plurality of base stations, wherein each base station is assigned a category of preference for server selection with respect to each neighboring cell in the plurality of cells having either a coextensive, adjacent, contiguous, or overlapping service area, and each base station is assigned a signal strength threshold for mobile station communications within the cell, a method for determining mobile station server selection of a base station, comprising the steps of:
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measuring the signal strength of communications between each mobile station and each of the base stations within communications range thereof; comparing the measured signal strength of communications with each candidate base station to the assigned signal strength threshold for that candidate base station; comparing the category of preference for each candidate base station to the category of preference for the base stations currently serving each of the mobile stations; and responsive to the foregoing comparisons making the mobile station server selection determination for each mobile station. - View Dependent Claims (25, 26, 27, 28, 29)
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30. A cellular communications system including a plurality of cells, comprising:
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a base station for each of the plurality of cells, wherein each base station is assigned a category of preference for server selection with respect to each neighboring cell in the plurality of cells having either a coextensive, adjacent, contiguous, or overlapping service area, and wherein each base station is further assigned a signal strength threshold for mobile station communications within the cell; a plurality of mobile stations moving through the plurality of cells and communicating with the plurality of base stations; means for measuring the signal strength of communications between the mobile stations and base stations; processing means connected to the means for measuring, said processing means executing a predetermined procedure for selecting a base station to serve each of the mobile stations, the selected base station having both the highest assigned category of preference and a measured signal strength of mobile station communications that exceeds the assigned base station signal strength threshold, said predetermined procedure followed for each mobile station in selecting the base station both for camping-on to a server during an idle operating mode and for handing-off between servers during a call processing mode.
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Specification