Uplink power control system for satellite communication system employing on-board satellite processing and fade estimation

• US 7,043,199 B2
• Filed: 06/06/2001
• Issued: 05/09/2006
• Est. Priority Date: 06/06/2001
• Status: Expired due to Term

• Current Assignee: Hughes Network Systems LLC (Echostar Corporation)
• Original Assignee: Hughes Network Systems LLC (Echostar Corporation)
• Inventors: Antia, Yezdi, Kay, Stan, Shi, Zhenliang, Khan, Anwer, Dai, Jerry, Zakaria, Gaguk
• Primary Examiner(s): Bui, Bing Q.
• Application Number:
  US09/875,607
• Publication Number:
  US 20030040274A1
• Time in Patent Office: 1,798 Days
• Field of Search: 455/427, 455/13.4, 455/12.1, 455/522, 455/134, 455/135, 455/136
• US Class Current: 455/13.4
• CPC Class Codes: H04B 7/18543 for adaptation of transmission parameters, e.g. power control for detecting or preventing errors in the information received H04L1/00

Abstract

An uplink power control system for terminals in a satellite communication system provides closed loop power control using feedback signals generated at a satellite. The satellite performs inter-beam routing of uplink signals from satellite terminals, and processing of uplink signals to generate terminal transmission-specific feedback information that is transmitted in downlink signals to the terminals. The satellite also generates a beacon signal. An uplink power control algorithm at each terminal uses the beacon signal and feedback data to adjust transmit power.

Claims

1. An uplink power control system for terminals in a satellite communication system comprising:

a satellite terminal operable to transmit uplink signals to and receive downlink signals from a satellite and comprising a programmable processing device, said downlink signals comprising feedback power data generated at said satellite in response to said uplink signals; and

a power control module operating with said processing device to adjust transmit power for said uplink signals in accordance with said feedback power data, wherein said power control module maintains and updates data relating to the uplink spectrum and adjusts said transmit power using said data;

wherein said downlink signals comprise a beacon signal, said power control module being operable to determine carrier to poise or C/N data using said beacon signal, to maintain and update fade data relating to estimated uplink fade using said C/N data, and wherein said spectrum data comprises the satellite terminal transmit spectrum and the satellite receive spectrum, said power control module adjusting said transmit power using said fade data and said spectrum data; and

wherein said downlink signal comprises an uplink power control status packet generated at said satellite for said terminal, said status packet comprising signal to noise ratio data corresponding to a frequency channel in said satellite communication channel on which said uplink signals are being transmitted, and further comprising a storage device for storing a plurality of filter tables for storing said fade data and said spectrum data, said power control module being operable to update said filter tables when said status packet is received.

2. A method for performing uplink power control for terminals in a satellite communication system comprising the steps of:

assigning a communication channel to a terminal for transmitting an uplink signal to a satellite, wherein said uplink signal includes data relating to the uplink spectrum;

processing said uplink signals at said satellite to obtain signal to noise data and spectrum data corresponding to said communication channel;

generating a feedback signal corresponding said processed uplink signal on said channel;

transmitting said feedback signal to said terminal; and

adjusting transmit power at said terminal in accordance with said feedback signal and updating spectrum data;

wherein said generating step comprises the steps of determining at least one of noise, signal-to-noise ratio and signal-to-noise and interference ratio of one of said uplink signals at said satellite, generating a status signal indicating at least one of noise, signal-to-noise ratio and signal-to-noise-interference ratio corresponding to said uplink signal, and transmitting said status signal to said terminal, said status signal being used by said terminal to determine said transmit power; and

wherein said terminal transmits said uplink signals at a selected data rate, and further comprising the step of determining whether said terminal should enter a fallback mode during which said terminal transmits said uplink signals at a lower data rate depending on said status signal.

3. A method for performing uplink power control for terminals in a satellite communication system comprising the steps of:

assigning a communication channel to a terminal for transmitting an uplink signal to a satellite, wherein said uplink signal includes data relating to the uplink spectrum;

processing said uplink signals at said satellite to obtain signal to noise data and spectrum data corresponding to said communication channel;

generating a feedback signal corresponding said processed uplink signal on said channel;

transmitting said feedback signal to said terminal; and

adjusting transmit power at said terminal in accordance with said feedback signal and updating spectrum data;

wherein said terminal transmits said uplink signals at a selected data rate, and further comprising the step of determining whether said terminal should enter a fallback mode during which said terminal transmits said uplink signals at a lower data rate when said feedback signal indicates excess attenuation due to rain.

4. A method as claimed in claim 3, wherein said terminal quits said fallback mode and resumes transmitting said uplink signals at a higher data rate than said lower data rate when said feedback signal no longer indicates said attenuation.