# US 10,312,965 B2 · Outbound interference reduction in a broadband powerline system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,312,965 B2 - Document ID: US10312965B2 - Status: Granted - Kind: B2 - Application number: 15/860,077 - Filed: 2018-01-02 - Published: 2018-05-03 - Granted: 2019-06-04 - Earliest claimed: 2004-05-06 - Assignees: AT&T Intellectual Property II, L.P. - Applicants: AT&T Intellectual Property II, L.P. - Inventors: Paul Shala Henry - Web page: https://patentgrep.com/patent/US10312965B2 ## CPC - H04B 3/30: Reducing interference caused by unbalanced currents in a normally balanced line - H04B 3/54: Systems for transmission via power distribution lines - H04B 3/542: {the information being in digital form} - H04B 3/56: Circuits for coupling, blocking, or by-passing of signals - H04J 1/08: Arrangements for combining channels {(branching filters H01P1/213, H03H7/46)} - H04L 5/0005: {Time-frequency} - H04L 25/028: {Arrangements specific to the transmitter end} - H04L 25/10: Compensating for variations in line balance - H04B 2203/5416: by adding signals to the wave form of the power source - H04B 2203/5425: improving S/N by matching impedance, noise reduction, gain control - H04B 2203/5483: using coupling circuits - H04B: TRANSMISSION - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## 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. ## Claims ### Claim 1 A method for reducing interference radiated by a powerline transmission system, the method 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 line and the second line of the powerline transmission system, wherein the powerline transmission system is a frequency division multiplexed system transmitting the first data and the second data on a plurality of frequency channels and the adjusting of the characteristic of the at least one of the modulated first carrier signal or the modulated second carrier signal is performed independently for each of the plurality of frequency channels. ### Claim 2 (depends on 1) The method of claim 1, wherein adjusting a characteristic of at least one of the modulated first carrier signal or the modulated second carrier signal based on the known imbalance between the first line and the second line to improve the electrical balance of the first line and the second line of the powerline transmission system comprises: adjusting a carrier signal phase of at least one of the modulated first carrier signal or the modulated second carrier signal based on the known imbalance between the first line and the second line to improve the electrical balance between the first and second lines of the powerline transmission system. ### Claim 3 (depends on 1) The method of claim 1, wherein adjusting a characteristic of at least one of the modulated first carrier signal or the modulated second carrier signal based on the known imbalance between the first line and the second line to improve the electrical balance of the first line and the second line of the powerline transmission system comprises: adjusting a carrier signal magnitude of at least one of the modulated first carrier signal or the modulated second carrier signal based on the known imbalance between the first line and the second line to improve the electrical balance between the first and second lines of the powerline transmission system. ### Claim 4 (depends on 1) The method of claim 1, wherein the known imbalance is a predetermined characteristic of the first and second lines. ### Claim 5 (depends on 1) 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 between the first line and the second line. ### Claim 6 (depends on 1) The method of claim 1, wherein adjusting a characteristic of at least one of the modulated first carrier signal or the modulated second carrier signal based on the known imbalance between the first line and the second line to improve the electrical balance of the first line and the second line of the powerline transmission system comprises: adjusting a phase independently for each of the frequency channels in the at least one of the modulated first carrier signal or the modulated second carrier signal. ### Claim 7 (depends on 1) The method of claim 1, wherein adjusting a characteristic of at least one of the modulated first carrier signal or the modulated second carrier signal based on the known imbalance between the first line and the second line to improve the electrical balance of the first line and the second line of the powerline transmission system comprises: adjusting an amplitude independently for each of the frequency channels in the at least one of the modulated first carrier signal or the modulated second carrier signal. ### Claim 8 A transmitter for use in a powerline communication system having a first transmission line and a second transmission line, the transmitter 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 powerline communication system is a frequency division multiplexed system transmitting the first data and the second data on a plurality of frequency channels and the differential driver performs the adjusting independently for each of the frequency channels. ### Claim 9 (depends on 8) The transmitter of claim 8, wherein the differential driver adjusts a carrier signal phase of at least one of the first carrier signal or the second carrier signal based on the known imbalance between the first transmission line and the second transmission line. ### Claim 10 (depends on 8) The transmitter of claim 8, wherein the differential driver adjusts a carrier signal phase of at least one of the first carrier signal or the second carrier signal based on the known imbalance between the first transmission line and the second transmission line. ### Claim 11 (depends on 8) The transmitter of claim 8, wherein the known imbalance is a predetermined characteristic of the first and second transmission lines. ### Claim 12 (depends on 8) The transmitter of claim 8, 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 between the first transmission line and the second transmission line. ### Claim 13 (depends on 8) The transmitter of claim 8, wherein the differential driver adjusts a phase independently for each of the frequency channels in the at least one of the first carrier signal or the second carrier signal. ### Claim 14 (depends on 8) The transmitter of claim 8, wherein the differential driver adjusts an amplitude independently for each of the frequency channels in the at least one of the first carrier signal or the second carrier signal. ### Claim 15 A method for reducing interference radiated by a powerline transmission system comprising: transmitting first and second data via respective modulated first and second carrier signals on respective first and second transmission lines of the powerline transmission system using differential excitation, wherein the powerline transmission system is a frequency division multiplexed system and the first and second data are transmitted via the respective modulated first and second carrier signals on a plurality of frequency channels; and generating the modulated first and second carrier signals having characteristics that are independently adjusted for each of the plurality of frequency channels to compensate for an imbalance between the first and second transmission lines of the powerline transmission system. ### Claim 16 (depends on 15) The method of claim 15, wherein generating the modulated first and second carrier signals having characteristics that are independently adjusted for each of the plurality of frequency channels to compensate for the imbalance between the first and second transmission lines of the powerline transmission system comprises: generating the modulated first and second carrier signals in which phases are adjusted independently for each of the plurality of frequency channels in the modulated first and second carrier signals to compensate for the imbalance between the first and second transmission lines of the powerline transmission system. ### Claim 17 (depends on 15) The method of claim 15, wherein generating the modulated first and second carrier signals having characteristics that are independently adjusted for each of the plurality of frequency channels to compensate for the imbalance between the first and second transmission lines of the powerline transmission system comprises: generating the modulated first and second carrier signals in which amplitudes are adjusted independently for each of the frequency channels in the modulated first and second carrier signals to compensate for the imbalance between the first and second transmission lines of the powerline transmission system. ### Claim 18 (depends on 15) The method of claim 15, wherein the imbalance is a predetermined characteristic of the first and second transmission lines. ### Claim 19 (depends on 15) The method of claim 15, wherein the imbalance is determined dynamically. ### Claim 20 (depends on 19) The method of claim 19, further comprising: dynamically adjusting a signal characteristic of at least one of the modulated first carrier signal or the modulated second carrier signal by independently adjusting the characteristics for each of the plurality of frequency channels in the at least one of the modulated first carrier signal or the modulated second carrier signal in response to a dynamically detected imbalance between the first and second transmission lines.