Method and system for compensating for atmospheric fading in a communications system
First Claim
1. A method for compensating for atmospheric fading in a communication system wherein signals are sent from a first earth station to a second earth station via a repeater above the atmosphere, without increasing power of the signals in said repeater, the method comprising:
- determining, at one or both of said earth stations, at various times, signal power of a received signal and a signal-to-noise ratio of a received signal;
calculating the change in noise power spectral density at said earth station from that under clear sky conditions, wherein the difference in noise power spectral density is calculated using the signal power and signal-to-noise ratio at one of said earth stations and a constant, K, wherein K is calculated as the difference, in dB, between the received signal strength under clear sky conditions and a signal-to-noise ratio under clear sky conditions;
calculating a downlink attenuation;
calculating an uplink attenuation present at a sending one of said earth stations; and
commanding a sending one of said earth stations to increase its transmit power by an amount to compensate for the uplink attenuation.
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Abstract
A method and system for compensating for atmospheric fading is used in a communication system wherein communication signals are exchanged between first and second earth stations via a satellite link, without increasing power of the satellite link. The method includes determining, at one or both of the earth stations, the signal power of a received signal and a signal-to-noise ratio of the received signal; calculating the difference in noise power spectral density in the received signal from that under clear sky conditions; calculating the downlink attenuation; determining the uplink attenuation, and commanding the transmitting earth station to increase its transmit power by an amount to compensate for the uplink attenuation. A corresponding system carries out the method.
63 Citations
34 Claims
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1. A method for compensating for atmospheric fading in a communication system wherein signals are sent from a first earth station to a second earth station via a repeater above the atmosphere, without increasing power of the signals in said repeater, the method comprising:
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determining, at one or both of said earth stations, at various times, signal power of a received signal and a signal-to-noise ratio of a received signal;
calculating the change in noise power spectral density at said earth station from that under clear sky conditions, wherein the difference in noise power spectral density is calculated using the signal power and signal-to-noise ratio at one of said earth stations and a constant, K, wherein K is calculated as the difference, in dB, between the received signal strength under clear sky conditions and a signal-to-noise ratio under clear sky conditions;
calculating a downlink attenuation;
calculating an uplink attenuation present at a sending one of said earth stations; and
commanding a sending one of said earth stations to increase its transmit power by an amount to compensate for the uplink attenuation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A system for compensating for atmospheric fading in a communication system wherein communication signals are exchanged between first and second earth stations via a repeater above the atmosphere, without increasing power of the repeater, the system comprising:
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means for determining, at one or both of the earth stations, the signal power of a received signal and a signal-to-noise ratio of the received signal;
means for calculating the difference in noise power spectral density at the receiving earth station from that under clear sky conditions, wherein the difference in noise power spectral density is calculated using the signal power and signal-to-noise ratio determined at said one of said earth stations and a constant, K, wherein K is calculated as the difference between the received signal strength under clear sky conditions and a signal-to-noise ratio under clear sky conditions;
means for calculating the downlink attenuation;
means for calculating the uplink attenuation; and
means for commanding a sending one of the earth stations to increase its transmit power by an amount to compensate for the uplink attenuation. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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Specification