Echo cancellation in a bidirectional communication system for out of band signaling to a user device
First Claim
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1. A method comprising:
- receiving, by a computing device, at least one first signal for a user device at a first frequency in a downstream band, wherein the user device is operable to receive signals having frequencies within a frequency range allocated for an upstream band, and said first frequency is outside of said frequency range;
converting, by a converter in the computing device, the at least one first signal to at least one second signal at a second frequency, wherein said second frequency is within the frequency range allocated for the upstream band for receipt by the user device;
providing said at least one second signal output from the converter to a first coupler;
outputting, by the computing device, the at least one second signal at the second frequency in a downstream direction, the at least one second signal at the second frequency being sent in the upstream band in the downstream direction, wherein the output of said second signal in the downstream direction in the upstream band by the computer device causes reflections in an upstream direction towards the first coupler;
sampling an output of reflections, caused by the at least one second signal output in the downstream direction in the upstream band, from a second coupler in the upstream path that includes the first coupler, a return amplifier, and the second coupler;
in response to sampling the output of reflections from the second coupler in the upstream path, generating a cancellation signal for outputting to said first coupler in addition to one or more subsequent converted signals converted for the user device,whereby said cancellation signal is adjustable in amplitude and/or phase in response to the sampling of reflections output from the second coupler; and
outputting the cancellation signal in the upstream path for canceling reflections caused by transmission of the at least one second signal output in the downstream direction in the upstream band.
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Abstract
Disclosed herein are techniques for bidirectional communication in a network, such as a cable television (CATV) system, for return band with echo cancellation. The techniques result in a minimum loss of available return bandwidth to facilitate forward out of band (OOB) communication to a client device, e.g., set top box (STB), within the extended return band, such as a return band extended beyond a frequency previously used for OOB communications.
24 Citations
15 Claims
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1. A method comprising:
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receiving, by a computing device, at least one first signal for a user device at a first frequency in a downstream band, wherein the user device is operable to receive signals having frequencies within a frequency range allocated for an upstream band, and said first frequency is outside of said frequency range; converting, by a converter in the computing device, the at least one first signal to at least one second signal at a second frequency, wherein said second frequency is within the frequency range allocated for the upstream band for receipt by the user device; providing said at least one second signal output from the converter to a first coupler; outputting, by the computing device, the at least one second signal at the second frequency in a downstream direction, the at least one second signal at the second frequency being sent in the upstream band in the downstream direction, wherein the output of said second signal in the downstream direction in the upstream band by the computer device causes reflections in an upstream direction towards the first coupler; sampling an output of reflections, caused by the at least one second signal output in the downstream direction in the upstream band, from a second coupler in the upstream path that includes the first coupler, a return amplifier, and the second coupler; in response to sampling the output of reflections from the second coupler in the upstream path, generating a cancellation signal for outputting to said first coupler in addition to one or more subsequent converted signals converted for the user device, whereby said cancellation signal is adjustable in amplitude and/or phase in response to the sampling of reflections output from the second coupler; and outputting the cancellation signal in the upstream path for canceling reflections caused by transmission of the at least one second signal output in the downstream direction in the upstream band. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus comprising:
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a first coupler for receiving at least one first signal for a user device, at a first frequency in a downstream band, wherein the user device is operable to receive signals having frequencies within a frequency range allocated for an upstream band, and said first frequency is outside of said frequency range; and a converter for; converting the at least one first frequency of the first signal to at least one second signal at a second frequency, wherein said second frequency is within the frequency range allocated for the upstream band for receipt by the user device; sampling an output of reflections, caused by the at least one second signal output in the downstream direction in the upstream band, from a third coupler in the upstream path that includes a second coupler, a return amplifier, and the third coupler; in response to sampling the output of reflections from the third coupler in the upstream path, generating a cancellation signal for outputting to said second coupler in addition to one or more subsequent converted signals converted for the user device, whereby said cancellation signal is adjustable in amplitude and/or phase in response to the sampling of reflections output from the third coupler; and an output for; outputting, by the computing device, the at least one second signal at the second frequency in a downstream direction, the at least one second signal at the second frequency being sent in the upstream band in the downstream direction, wherein the output of said at least one second signal in the downstream direction in the upstream band by the computer device causes reflections in an upstream direction towards the third coupler; and outputting the cancellation signal in the upstream path for canceling reflections caused by transmission of the at least one second signal output in the downstream direction in the upstream band. - View Dependent Claims (11, 12, 13, 14, 15)
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Specification