Communications adaptive automatic gain controller

• US 20090067556A1
• Filed: 09/11/2007
• Published: 03/12/2009
• Est. Priority Date: 09/11/2007
• Status: Active Grant

• Current Assignee: Aerospace Corporation
• Original Assignee: Aerospace Corporation
• Inventors: McDonald, Eric J., Grayver, Eugene
• Granted Patent: US 7,970,084 B2
• Time in Patent Office: Days
• US Class Current: 375/345
• CPC Class Codes: H03G 3/3052 in bandpass amplifiers (H.F. or I.F.) or in frequency-changers used in a (super)heterodyne receiver H03G3/32, H03G3/34 take precedence
• CPC Class Codes: H04L 27/08 Amplitude regulation arrangements
• CPC Class Codes: H04L 27/3411 reducing the peak to average power ratio or the mean power of the constellation; Arrangements for increasing the shape gain of a signal set
• CPC Class Codes: H04L 27/368 adaptive predistortion

Abstract

An adaptive scaling processor operates in combination with a conventional automatic gain control controller providing an amplification gain A to m-ary symbol-modulated communication signals, the scaling processor scaling by a scaling factor Z the m-ary communication signal for providing an over all gain of an (A)(Z) product minimizing the BER that is optimum for the communications channel for improved BER performance in communication systems.

Claims

1. A controller for providing an output signal from an input signal, the input signal and output signal are m-ary signals modulated within a constellation space defining communicated symbols communicated in the input signal, the controller comprising,

a gain controller for receiving the input signal and providing automatic gain control of the input signal for generating an adjusted input signal, the automatic gain control serving to align the adjusted input signal to the constellation space, and

a scaling processor for receiving the adjusted input signal and scaling the adjusted input signal into the output signal.

2. The controller of claim 1 wherein,

the output signal carries the symbols that are misaligned to the constellation space generating a bit error rate, and

the scaling factor is adjusted by the scaling processor to minimize the bit error rate.

3. The controller of claim 1 wherein the scaling processor comprises,

an adaptive processor receiving a parameter for generating the scaling factor, and

a multiplier for scaling the adjusted input into the output.

4. The controller of claim 1 wherein the scaling processor comprises,

an adaptive processor receiving a parameter for generating the scaling factor, the parameter indicating a bit error rate, and

a multiplier for scaling the adjusted input into the output,

wherein,

the output carries the symbols that are misaligned to the constellation space generating the bit error rate, and

the scaling factor is adjusted by the scaling processor to minimize the bit error rate.

5. The controller of claim 1 wherein, the scaling processor comprises,

an adaptive processor receiving a parameter for generating the scaling factor, the parameter indicating a bit error rate, and

a multiplier for scaling the adjusted input into the output,

wherein,

the output carries the symbols that are misaligned to the constellation space generating the bit error rate,

the scaling factor is adjusted by the scaling processor to minimize the bit error rate, and

the parameter is an input indicating a packet error rate.

6. The controller of claim 1 wherein, the scaling processor comprises,

an adaptive processor receiving a parameter for generating the scaling factor, the parameter indicating a bit error rate, and

a multiplier for scaling the adjusted input into the output,

wherein,

the output carries the symbols that are misaligned to the constellation space generating the bit error rate,

the scaling factor is adjusted by the scaling processor to minimize the bit error rate, and

the parameter is an input indicating an error correction code error rate.

7. The controller of claim 1 wherein the scaling processor comprises,

an adaptive processor receiving a parameter for generating the scaling factor, the parameter indicating a bit error rate,

a parameter estimator for estimating a parameter indicating the bit error rate, and

a multiplier for scaling the adjusted input into the output,

wherein,

the output carries the symbols that are misaligned to the constellation space generating the bit error rate, and

the scaling factor is adjusted by the scaling processor to minimize the bit error rate.

8. The controller of claim 1 wherein the scaling processor comprises,

an adaptive processor receiving a parameter for generating the scaling factor, the parameter indicating a bit error rate,

a parameter estimator for estimating a parameter indicating the bit error rate, and

a multiplier for scaling the adjusted input into the output,

wherein,

the output carries the symbols that are misaligned to the constellation space generating the bit error rate,

the scaling factor is adjusted by the scaling processor to minimize the bit error rate, and

the parameter is selected from a plurality of signal to noise ratio parameters precomputed prior to receiving the input signal.

9. A controller for providing an output signal from an input signal, the input signal and output signal are m-ary signals modulated within a constellation space defining communicated symbols communicated in the input signal, the controller comprising,

a gain controller for receiving the input signal and providing automatic gain control of the input signal for generating an adjusted input signal, the automatic gain control serving to align the adjusted input to the constellation space,

a multiplier for scaling the adjusted input by a scaling factor into the output, and

an adaptive processor for receiving the adjusted input signal and scaling the adjusted input signal into the output signal, the output signal indicates symbols that are misaligned to the constellation space generating the bit error rate, and the adaptive processor for receiving a parameter for generating the scaling factor, the parameter indicating a bit error rate.

10. The controller of claim 9 wherein,

the scaling factor is adjusted by the adaptive processor to minimize the bit error rate.

11. The controller of claim 9 wherein,

the controller receives as input the parameter.

12. The controller of claim 9 wherein,

the constellation space is a 16-ary constellation space.

13. The controller of claim 9 wherein the parameter is a signal to noise parameter, the controller further comprising,

a parameter generator for generating the signal to noise parameter, the adaptive processor providing the scaling factor from a look up table index to the signal to noise parameter.

14. The controller of claim 9 wherein the parameter is a bit error rate parameter, the controller further comprising,

a parameter generator for generating the bit error rate parameter, the adaptive processor for increasing and decreasing the scaling factor to minimize the bit error rate.