Closed loop power control for low earth orbit satellite communications system
First Claim
1. A method for operating a satellite communication system having at least one satellite, at least one ground station, and at least one user terminal, comprising the steps of:
- measuring a quality of at least one reference signal received by the user terminal, the reference signal being transmitted by the ground station through the satellite;
transmitting the measured quality of the reference signal received by the user terminal to the ground station;
comparing the measured quality with a predetermined reference; and
adjusting a transmit power of the ground station in response to a difference between the predetermined reference and measured quality, wherein the transmit power of the ground station is adjusted so that a flux density of a downlink beam is substantially constant at the user terminal independent of the location of the user terminal in the beam.
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Accused Products
Abstract
A satellite communication system (10) includes at least one satellite communication signal repeater (12); at least one ground station (18) for transmitting a feeder link comprised of a plurality of communication signals to the at least one satellite communication signal repeater; and a plurality of user terminals (13) each receiving one of the communication signals over a user link from the at least one satellite communication signal repeater. A method includes steps of measuring a quality of at least one reference signal received by the user terminal, via the satellite; transmitting the measured quality of the reference signal received by the user terminal to the ground station; comparing the measured quality with a predetermined reference; and adjusting a transmit power of the ground station in response to a difference between the predetermined reference and measured quality. The transmit power of the ground station is adjusted so that a flux density of a downlink beam is substantially constant at the user terminal independent of the location of the user terminal in the beam.
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Citations
9 Claims
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1. A method for operating a satellite communication system having at least one satellite, at least one ground station, and at least one user terminal, comprising the steps of:
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measuring a quality of at least one reference signal received by the user terminal, the reference signal being transmitted by the ground station through the satellite;
transmitting the measured quality of the reference signal received by the user terminal to the ground station;
comparing the measured quality with a predetermined reference; and
adjusting a transmit power of the ground station in response to a difference between the predetermined reference and measured quality, wherein the transmit power of the ground station is adjusted so that a flux density of a downlink beam is substantially constant at the user terminal independent of the location of the user terminal in the beam. - View Dependent Claims (2, 3)
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4. A satellite communication system comprised of at least one satellite and at least one ground station, said satellite communication system further comprising:
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means for transmitting an uplink reference signal;
the satellite comprising a receiver for receiving the reference signal and further comprising a transmitter for transmitting the reference signal as a repeated downlink reference signal;
at least one user terminal with a receiver for receiving the reference signal repeated by the satellite, the user terminal having means for measuring a quality of the reference signal received by the user terminal, and having means for transmitting the measured quality; and
a processor coupled to the ground station for adjusting a transmit power of the ground station based on the measured quality transmitted by the user terminal, the processor being programmed to at least one of adjust the transmit power such that a flux density of a downlink beam from the satellite is substantially constant at the user terminal independent of the location of the user terminal in the beam or adjust the transmit power to compensate for predicted variation in satellite gain and maintain the flux density of the beam above a predetermined threshold at the location of the user terminal.
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5. A method for operating a satellite communication system having at least one satellite, at least one ground station, and a plurality of user terminals located in downlink beams of the satellite, the plurality of user terminals including a plurality of types of user terminals, the method comprising the steps of:
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measuring a quality of reference signals received by the user terminals, the reference signals being transmitted by the ground station through the satellite;
transmitting the measured quality of the reference signals received by the user terminals to the ground station;
comparing the measured quality with a predetermined reference; and
adjusting the transmit power of the ground station to at least one of provide a predetermined percentage of all user terminals in a given one of the downlink beams with downlink signal quality above a common predetermined threshold, or to provide a predetermined percentage of each type of user terminal in the beam with downlink signal quality above a corresponding predetermined threshold set independently for each type of user terminal. - View Dependent Claims (6, 7, 8, 9)
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Specification