Capacity maximization for a unicast spot beam satellite system
DCFirst Claim
1. A satellite comprising:
- a power source;
a plurality of amplifiers for generating a plurality of spot beams; and
an antenna for transmitting the plurality of spot beams to illuminate a corresponding plurality of regions on Earth, the plurality of spot beams including a spot beam illuminating a region at least partially overlapping with regions illuminated by one or more neighboring spot beams to result in interference;
wherein the spot beam services a first subscriber terminal located in a first area closer to the center of the region illuminated by spot beam and a second subscriber terminal located in a second area closer to the periphery of the region illuminated by the spot beam;
wherein the spot beam comprises a signal having a first portion sent with a first modcode destined for the first subscriber terminal located in the first area closer to the center of the illuminated region, the signal having a second portion sent with a second modcode destined for the second subscriber terminal located in the second area closer to the periphery of the illuminated region, wherein the first modcode corresponds to a higher data rate than the second modcode; and
wherein modcodes of signals sent to the first and second subscriber terminals are adjusted according to an adaptive modulation and coding (ACM) scheme based on link quality information collected from the first and second subscriber terminals, to mitigate effects of interference from the one or more neighboring spot beams.
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Accused Products
Abstract
Methods, systems, and apparatuses are presented for improved satellite communications. The satellite system may comprises at least one gateway, a satellite in orbit configured to communicate with the at least one gateway and provide a plurality of spot beams, and a plurality of subscriber terminals. The spot beams may include a first spot beam to illuminate a first region and a second spot beam to illuminate a second region adjacent to and overlapping with the first region. The first spot beam as sent to at least one subscriber terminal may be affected by (1) interference from other signal sources including the second spot beam at a signal-to-interference ratio C/I and (2) noise at a signal-to-noise ratio C/N. Reception of signals from the first spot beam by the at least one of the first plurality of subscriber terminals may be interference-dominated such that C/I is less than C/N.
25 Citations
21 Claims
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1. A satellite comprising:
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a power source; a plurality of amplifiers for generating a plurality of spot beams; and an antenna for transmitting the plurality of spot beams to illuminate a corresponding plurality of regions on Earth, the plurality of spot beams including a spot beam illuminating a region at least partially overlapping with regions illuminated by one or more neighboring spot beams to result in interference; wherein the spot beam services a first subscriber terminal located in a first area closer to the center of the region illuminated by spot beam and a second subscriber terminal located in a second area closer to the periphery of the region illuminated by the spot beam; wherein the spot beam comprises a signal having a first portion sent with a first modcode destined for the first subscriber terminal located in the first area closer to the center of the illuminated region, the signal having a second portion sent with a second modcode destined for the second subscriber terminal located in the second area closer to the periphery of the illuminated region, wherein the first modcode corresponds to a higher data rate than the second modcode; and wherein modcodes of signals sent to the first and second subscriber terminals are adjusted according to an adaptive modulation and coding (ACM) scheme based on link quality information collected from the first and second subscriber terminals, to mitigate effects of interference from the one or more neighboring spot beams. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A satellite system comprising:
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a gateway; a satellite for generating a plurality of spot beams based on signals originating from the gateway, the plurality of spot beams including a spot beam illuminating a region at least partially overlapping with regions illuminated by one or more neighboring spot beams; and a plurality of subscriber terminals serviced by the plurality of spot beams, including a first subscriber terminal located in a first area closer to the center of the region illuminated by the spot beam and a second subscriber terminal located in a second area closer to the periphery of the region illuminated by the spot beam; wherein the spot beam comprises a signal having a first portion sent with a first modcode destined for the first subscriber terminal located in the first area closer to the center of the illuminated region, the signal having a second portion sent with a second modcode destined for the second subscriber terminal located in the second area closer to the periphery of the illuminated region, wherein the first modcode corresponds to higher data rate than the second modcode; and wherein modcodes of signals sent to the first and second subscriber terminals are continually adjusted according to an adaptive modulation and coding (ACM) scheme based on link quality information collected from the first and second subscriber terminals, to mitigate effects of interference from the one or more neighboring spot beams.
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10. A method for configuring a satellite comprising:
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selecting a spot beam pattern comprising a plurality of spot beams arranged in a pattern to cover a geographic area, the spot beam pattern producing interference between spot beams; calculating different signal qualities at different subscriber terminals positioned at various locations within a spot beam belonging to the spot beam pattern; modeling an average capacity for the spot beam from location-specific capacities for the different subscriber terminals positioned at various locations within the spot beam, wherein the location-specific capacities are determined from the different signal qualities at the different subscriber terminals; and selecting at least one satellite system parameter of the satellite based at least in part on the average capacity for the spot beam. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification