Outbound interference reduction in a broadband powerline system

Patent metadata

Field	Value
Publication number	US-9577706-B2
Application number	US-201414551582-A
Country	US
Kind code	B2
Filing date	Nov 24, 2014
Priority date	May 6, 2004
Publication date	Feb 21, 2017
Grant date	Feb 21, 2017

Abstract

Disclosed is a method and apparatus for reducing outbound interference in a broadband powerline communication system. Data is modulated on first and second carrier frequencies and is transmitted via respective first and second lines of the powerline system. A characteristic of at least one of the carrier signals (e.g., phase or amplitude) is adjusted in order to improve the electrical balance of the lines of the transmission system. This improvement in electrical balance reduces the radiated interference of the powerline system. Also disclosed is the use of a line balancing element on or more lines of the powerline system for altering the characteristics of at least one of the power lines in order to compensate for a known imbalance of the transmission system.

First claim

The invention claimed is:

1. A method for reducing interference radiated by a powerline transmission system, comprising:
transmitting first data via a modulated first carrier signal on a first line of the powerline transmission system;
transmitting second data via a modulated second carrier signal on a second line of the powerline transmission system; and
adjusting a characteristic of at least one of the modulated first carrier signal or the modulated second carrier signal based on a known imbalance between the first line and the second line to improve an electrical balance of the first and second lines of the powerline transmission system, wherein the characteristic is carrier signal magnitude.

2. The method of claim 1 , wherein the powerline transmission system is a frequency division multiplexed system transmitting data on a plurality of frequency channels.

3. The method of claim 2 , wherein adjusting is performed independently for each of the frequency channels.

4. The method of claim 1 , further comprising adjusting the characteristic of the at least one of the modulated first carrier signal or the modulated second carrier signal in response to a dynamic determination of an imbalance in the first and second lines.

5. The method of claim 1 , wherein the known imbalance is a predetermined characteristic of the first and second lines.

6. A transmitter for use in a powerline communication system having a first transmission line and a second transmission line, comprising:
at least one modulator for modulating first data onto a first carrier signal and for modulating second data onto a second carrier signal; and
a differential driver connected to the at least one modulator for adjusting a characteristic of at least one of the first “carrier signal or the second carrier signal to improve an electrical balance of the powerline communication system based on a known imbalance between the first transmission line and the second transmission line, wherein the characteristic is carrier signal magnitude.

7. The transmitter of claim 6 , wherein the powerline communication system is a frequency division multiplexed system transmitting data on a plurality of frequency channels.

8. The transmitter of claim 7 , wherein the differential driver performs the adjusting independently for each of the frequency channels.

9. The transmitter of claim 6 , wherein the differential driver adjusts the characteristic of the at least one of the first carrier signal or the second carrier signal in response to a dynamic determination of an imbalance in the first and second transmission lines.

10. The transmitter of claim 6 , wherein the known imbalance is a predetermined characteristic of the first and second lines.

11. A method for reducing interference radiated by a powerline transmission system, comprising:
transmitting data via a plurality of modulated carrier signals on respective ones of a plurality of lines of the powerline transmission system;
adjusting a characteristic of at least one of the plurality of modulated carrier signals based on a known imbalance between the plurality of lines to improve an electrical balance between the plurality of lines of the powerline transmission system, wherein the characteristic is carrier signal magnitude.

12. The method of claim 11 , wherein the powerline transmission system is a frequency division multiplexed system transmitting data on a plurality of frequency channels.

13. The method of claim 12 , wherein adjusting is performed independently for each of the frequency channels.

14. The method of claim 11 , further comprising adjusting the characteristic of the at least one of the plurality of modulated carrier signals in response to a dynamic determination of an imbalance in the plurality of lines.

15. The method of claim 11 , wherein the known imbalance is a predetermined characteristic of the plurality of lines.

Assignees

• At & T Ip Ii Lp

Inventors

• Henry Paul Shala

Classifications

• H04B3/542

  the information being in digital form · CPC title

• H04L25/10

  Compensating for variations in line balance · CPC title

• H04B2203/5416

  by adding signals to the wave form of the power source · CPC title

• H04B2203/5425

  improving S/N by matching impedance, noise reduction, gain control · CPC title

• H04B3/56

  Circuits for coupling, blocking, or by-passing of signals · CPC title