System and method for gain control of individual narrowband channels using a wideband power measurement

• US 20010026579A1
• Filed: 04/09/2001
• Published: 10/04/2001
• Est. Priority Date: 09/09/1998
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Thompson, James H., Mollenkopf, Steven
• Granted Patent: US 6,377,786 B2
• Time in Patent Office: Days
• US Class Current: 375/141
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04W 52/10 Open loop power control

Abstract

The present invention comprises a system and method for gain control of individual narrowband channels using a wideband power measurement. The present invention comprises a transmit power tracking loop which controls the power of the transmitted signal by controlling the gain applied to the signal. The function of the transmit power tracking loop is to measure power, accept commands for power adjustment, and adjust the power. Gain control is performed by producing an error signal using the comparison of measurements of a total of estimated powers of each narrowband signal and a measurement of the modulated wideband signal. In addition, open loop control is performed by accepting open loop commands generated by an algorithm.

Claims

1. A system for tracking power comprising:

a plurality of estimators;

a transmit power tracking loop coupled to each one of said plurality of estimators; and

an amplifier coupled to said transmit power tracking loop.

2. The system of

claim 1

, wherein said transmit power tracking loop comprises:

pre-amplification power estimation means for obtaining a power estimate prior to amplification by said amplifier;

post-amplification power estimation means for obtaining a power measurement after amplification by said amplifier; and

error signal determination means for determining the difference between said power estimate prior to amplification by said amplifier and said power measurement after amplification by said amplifier.

3. The system of

claim 1

, wherein said transmit power tracking loop comprises:

an estimator summer coupled to said plurality of estimators;

a logarithm converter coupled to said estimator summer;

a first transmit power tracking loop summer having one or more transmit power tracking loop summer inputs and a first transmit power summer output, wherein one or said one or more transmit power tracking loop summer inputs is coupled to said logarithm converter;

a wideband power meter coupled to a second of said one or more transmit power tracking loop summer inputs and to an antenna input;

an open loop command generator coupled to a third of said one or more transmit power tracking loop summer inputs;

a second transmit power tracking loop summer having one or more second transmit power tracking loop summer inputs and a second transmit power tracking loop summer output, wherein one of said second transmit power tracking loop summer inputs is coupled to said first transmit power tracking loop summer output and a second of said one or more inputs is coupled to said open loop command generator; and

a digital to analog converter coupled to said second transmit power tracking loop summer output and said amplifier.

4. The system of

claim 1

, wherein said transmit power tracking loop comprises:

an estimator summer coupled to said plurality of estimators;

a logarithm converter coupled to said estimator summer;

an estimate filter coupled to said logarithm converter;

a first transmit power tracking loop summer having one or more transmit power tracking loop summer inputs and a first transmit power summer output, wherein one or said one or more transmit power tracking loop summer inputs is coupled to said estimate filter;

an output power measurement digital filter applied coupled to a second one of said one or more first transmit power tracking loop summer inputs;

a wideband power meter coupled to said output power measurement digital filter and to an antenna input;

an open loop command generator coupled to a third of said one or more transmit power tracking loop summer inputs;

an error signal digital filter coupled to said first transmit power tracking loop summer output;

a second transmit power tracking loop summer having one or more second transmit power tracking loop summer inputs and a second transmit power tracking loop summer output, wherein one of said second transmit power tracking loop summer inputs is coupled to said error signal digital filter and a second of said one or more inputs is coupled to said open loop command generator; and

a digital to analog converter coupled to said second transmit power tracking loop summer output and said amplifier.

5. A system for modulating an information signal in a spread spectrum communication system, comprising:

a modulator having a modulator input and a modulator output;

an upconverter coupled to said modulator input;

a summer coupled to said upconverter;

an amplifier having an amplifier input and an amplifier output, wherein said amplifier input is coupled to said summer;

analog hardware having an analog hardware input and an analog hardware output, wherein said analog hardware input is coupled to said amplifier output;

an antenna having an antenna input and an antenna output, said antenna input being coupled to said analog hardware output; and

a transmit power tracking loop coupled to said modulator output, said amplifier input, and said analog hardware output.

6. The system of

claim 5

, wherein said transmit power tracking loop comprises:

pre-amplification power estimation means for obtaining a power estimate prior to amplification by said amplifier;

post-amplification power estimation means for obtaining a power measurement after amplification by said amplifier; and

error signal determination means for determining the difference between said power estimate prior to amplification by said amplifier and said power measurement after amplification by said amplifier.

7. The system of

claim 5

, wherein said transmit power tracking loop comprises:

an estimator summer coupled to said plurality of estimators;

a logarithm converter coupled to said estimator summer;

a first transmit power tracking loop summer having one or more transmit power tracking loop summer inputs and a first transmit power summer output, wherein one or said one or more transmit power tracking loop summer inputs is coupled to said logarithm converter;

a wideband power meter coupled to a second of said one or more transmit power tracking loop summer inputs and to an antenna input;

an open loop command generator coupled to a third of said one or more transmit power tracking loop summer inputs;

a second transmit power tracking loop summer having one or more second transmit power tracking loop summer inputs and a second transmit power tracking loop summer output, wherein one of said second transmit power tracking loop summer inputs is coupled to said first transmit power tracking loop summer output and a second of said one or more inputs is coupled to said open loop command generator; and

a digital to analog converter coupled to said second transmit power tracking loop summer output and said amplifier.

8. The system of

claim 5

, wherein said transmit power tracking loop comprises:

an estimator summer coupled to said plurality of estimators;

a logarithm converter coupled to said estimator summer;

an estimate filter coupled to said logarithm converter;

a first transmit power tracking loop summer having one or more transmit power tracking loop summer inputs and a first transmit power summer output, wherein one or said one or more transmit power tracking loop summer inputs is coupled to said estimate filter;

an output power measurement digital filter applied coupled to a second one of said one or more first transmit power tracking loop summer inputs;

a wideband power meter coupled to said output power measurement digital filter and to an antenna input;

an open loop command generator coupled to a third of said one or more transmit power tracking loop summer inputs;

an error signal digital filter coupled to said first transmit power tracking loop summer output;

a second transmit power tracking loop summer having one or more second transmit power tracking loop summer inputs and a second transmit power tracking loop summer output, wherein one of said second transmit power tracking loop summer inputs is coupled to said error signal digital filter and a second of said one or more inputs is coupled to said open loop command generator; and

a digital to analog converter coupled to said second transmit power tracking loop summer output and said amplifier.

9. A system for modulating an information signal in a spread spectrum communication system, comprising:

a plurality of modulators, wherein each one of said plurality of modulators has a modulator input and a modulator output;

a plurality of upconverters, wherein each one of said plurality of upconverters is coupled to a corresponding one of said modulator inputs;

a summer coupled to said upconverters;

an amplifier having an amplifier input and an amplifier output, wherein said amplifier input is coupled to said summer;

analog hardware having an analog hardware input and an analog hardware output, wherein said analog hardware input is coupled to said amplifier output;

an antenna coupled to said analog hardware output; and

a transmit power tracking loop coupled to each one of said modulator outputs, said amplifier input, and said analog hardware output.

10. In a system for modulating a plurality of narrowband information signals, a method for controlling a power of said narrowband information signals, comprising the steps of:

(a) receiving each one of said narrowband information signals from a corresponding one of a plurality of modulators into a corresponding one of a plurality of estimators;

(b) measuring an estimated power of said narrowband information signals;

(c) sending said estimate powers to an estimator summer;

(d) summing said estimated power of said narrowband information signals for a total estimated power of said narrowband information signals;

(e) receiving said total estimated power of said narrowband information signals by a transmit power tracking loop summer;

(f) measuring a wideband signal power of a wideband signal with a power meter;

wherein said wideband signal results from the modulation of said one or more narrowband information signals;

(g) receiving said wideband signal power from said power meter by said transmit power tracking loop summer;

(h) obtaining the difference of said total estimated power minus said wideband signal power;

(i) sending an error signal from said gain control unit to an amplifier; and

(j) amplifying said narrowband information signals according to said error signal.

11. A system for tracking power comprising:

means for determining an estimated power of a narrowband information signal;

means for summing one or more estimated powers of one or more narrowband information signals to produce a total estimated power;

means for measuring a wideband signal power of a wideband signal, wherein said wideband signal resulted from the modulation of said one or more narrowband information signals; and

means for controlling the gain of said one or more information signals using an error signal resulting from a comparison of said total estimated power and said wideband signal power.

12. A computer program product comprising a computer useable medium having computer program logic recorded thereon for enabling a processor in a computer system to track power, said computer logic comprising:

estimated power determining means for enabling a processor to determine an estimated power of a narrowband information signal;

estimated power summing means for enabling said processor to control summing one or more estimated powers of one or more narrowband information signals producing a total estimated power;

wideband signal power measurement means for enabling said processor to control measuring a wideband signal power of a wideband signal, wherein said wideband signal resulted from the modulation of said one or more narrowband information signals; and

gain controlling means for enabling said processor to control the gain of said one or more information signals using an error signal resulting from a comparison of said total estimated power and said wideband signal power.

13. A method of controlling gain of a modulator, comprising:

obtaining a transponder gain;

obtaining an antenna elevation;

calculating path gain using said antenna elevation;

calculating a modulator gain using said path gain and said transponder gain; and

adjusting the gain of the modulator.

14. A system for controlling gain of a modulator, comprising:

first obtaining means for obtaining a transponder gain;

second obtaining means for obtaining an antenna elevation;

first calculating means for calculating path gain using said antenna elevation;

second calculating means for calculating a modulator gain using said path gain and said transponder gain; and

adjusting means for adjusting the gain of the modulator.

15. A method of controlling gain input into an antenna, comprising:

obtaining an antenna elevation;

calculating path gain using said antenna elevation;

obtaining a transponder gain;

obtaining an antenna dish gain;

calculating a common gateway gain using said path gain, said transponder gain, and said antenna dish gain;

adjusting the gain of a variable gain amplifier.

16. A system of controlling gain input into an antenna, comprising:

first obtaining means for obtaining an antenna elevation;

first calculating means for calculating path gain using said antenna elevation;

second obtaining means for obtaining a transponder gain;

third obtaining means for obtaining an antenna dish gain;

second calculating means for calculating a common gateway gain using said path gain, said transponder gain, and said antenna dish gain;

adjusting means for adjusting the gain of a variable gain amplifier.