Communication system employing spectrum reuse on a spherical surface
First Claim
1. A method of operating M antennas traveling around the earth substantially in N different orbits, where M and N are integer numbers, wherein each of said antennas projects a footprint earthward which is divided into a plurality of cells and each of said antennas is controlled by a transceiver corresponding thereto, said method comprising steps of:
- generating definitions comprising a multiplicity of momentary channel-to-cell assignment definitions, each of said definitions associating channels with said cells in accordance with a spectrum assignment plan that spaces co-channel cells at least a predetermined distance apart, said multiplicity of momentary channel-to-cell assignment definitions characterizing cell locations at a multiplicity of points in time succeeding one another;
evaluating said multiplicity of definitions to determine ones of said cells and corresponding points in time for which channel assignments change and to determine new channel assignments; and
controlling said transceivers to operate in accordance with said evaluating step.
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Accused Products
Abstract
Orbiting satellites (12) project footprints (30) on the earth. Each footprint (30) is divided into cells (28). Footprints (30) of nearby satellites (12) overlap one another, and the overlap increases as satellites (12) approach a pole from the equator. Positions of all cells (28) generated by all satellites (12) are simulated (36) at numerous points throughout an orbit. Channel sets are assigned to cells (28) within a reference footprint (30a). This assignment is propagated throughout all footprints (30) except for those footprints (30) residing adjacent one side of a seam (16) between orbits (14) where satellites (12) travel in opposing directions. The channel sets are assigned near the seam (16) in response to previously assigned channel sets. Each satellite (12) stores channel set assignments for its cells (28) at various points throughout its orbit. All satellites (12) switch their communication parameters simultaneously in response to the channel set assignments.
63 Citations
24 Claims
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1. A method of operating M antennas traveling around the earth substantially in N different orbits, where M and N are integer numbers, wherein each of said antennas projects a footprint earthward which is divided into a plurality of cells and each of said antennas is controlled by a transceiver corresponding thereto, said method comprising steps of:
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generating definitions comprising a multiplicity of momentary channel-to-cell assignment definitions, each of said definitions associating channels with said cells in accordance with a spectrum assignment plan that spaces co-channel cells at least a predetermined distance apart, said multiplicity of momentary channel-to-cell assignment definitions characterizing cell locations at a multiplicity of points in time succeeding one another; evaluating said multiplicity of definitions to determine ones of said cells and corresponding points in time for which channel assignments change and to determine new channel assignments; and controlling said transceivers to operate in accordance with said evaluating step. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of reusing spectrum at a plurality of antennas which move with respect to a surface, said method comprising steps of:
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(a) simulating locations at a point in time for a plurality of footprints projected toward said surface from said plurality of antennas, wherein each of said antennas'"'"' corresponding footprints is divided into a plurality of cells; (b) generating a momentary channel-to-cell assignment definition by associating channels of said spectrum with at least a portion of said cells simulated in said step (a), said channels being associated in accordance with a spectrum assignment plan that spaces co-channel cells a predetermined distance apart; (c) repeating said steps (a) and (b) for a plurality of succeeding points in time to simulate movement of said antennas and to generate a plurality of momentary channel-to-cell assignment definitions; and (d) communicating through said antennas in accordance with said plurality of momentary channel-to-cell assignment definitions. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A system for cellular communication which reuses spectrum, said spectrum comprising channels, throughout an area covered by the system and which occasionally changes allocations of said channels to cells, said system comprising:
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M satellites traveling around the earth substantially in N different orbits, where M an N are integer numbers, wherein each of said M satellites includes one or more antennas that project a footprint earthward, which footprint is divided into a plurality of said cells; and a control station in data communication with each of said M satellites and configured to; generate a multiplicity of definitions of momentary channel-to-cell assignment, each of said multiplicity of definitions associating channels with said cells in accordance with a spectrum assignment plan that spaces co-channel cells a predetermined distance apart, said multiplicity of definitions characterizing cell locations at a multiplicity of succeeding points in time, evaluate said multiplicity of definitions to determine ones of said cells and corresponding points in time at which channel assignments change and to determine new channel assignments associated therewith, and communicate identities for said ones of said cells, said corresponding points in time, and said new channel assignments to said M satellites. - View Dependent Claims (23)
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24. A method of operating antennas which are traveling orbitally, each of said antennas centripetally projecting a footprint comprising cells, each of said antennas controlled by a transceiver corresponding thereto, said method comprising steps of:
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generating a multiplicity of definitions assigning momentary channel-to-cell correspondences, each of said definitions associating channels with said cells in accordance with a spectrum assignment plan that spaces co-channel cells at least a predetermined distance apart, said definitions characterizing cell locations at a multiplicity of succeeding points in time; evaluating said definitions to determine ones of said cells and corresponding points in time for which channel assignments change and to determine new channel-to-cell assignments; and controlling said transceivers to operate in accordance with said evaluating step.
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Specification