Method and system for varying an echo canceller filter length based on data rate
First Claim
1. A method for adapting a filter length of an echo canceller filter based on data rate, the method comprising the steps of:
- measuring a plurality of approximate filter lengths at a plurality of data rates;
fitting a polynomial to a curve representing the approximate filter lengths at the plurality of data rates;
inputting a selected data rate to a function of the polynomial for generating an approximate number of filter taps for modeling an echo channel for the selected data rate; and
adjusting the number of filter taps based on the selected data rate;
wherein a mean square error associated with the echo canceller filter is reduced.
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Abstract
The present invention provides methods and systems for providing efficient use of available CPU cycles that may be achieved by reducing the length of the echo canceller filter. An echo canceller'"'"'s adaptive algorithm may be implemented to reach a lower mean squared error due to the increased training time allowed by cycle reduction. Total power consumption of a processor may be reduced by reducing the number of multiplications (and/or other operations) that may be performed by an echo canceller filter for each time iteration. This may be achieved by not performing multiplications on taps that are not being used. For higher rates, a shorter echo canceller filter may be implemented by transmitting less energy in low frequencies. As a result, the temporal length of the echo channel may be shortened thereby reducing the total number of taps needed to model the channel. The present invention may further enhance performance by reducing CPU cycles and allowing for more echo canceller training time.
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Citations
38 Claims
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1. A method for adapting a filter length of an echo canceller filter based on data rate, the method comprising the steps of:
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measuring a plurality of approximate filter lengths at a plurality of data rates;
fitting a polynomial to a curve representing the approximate filter lengths at the plurality of data rates;
inputting a selected data rate to a function of the polynomial for generating an approximate number of filter taps for modeling an echo channel for the selected data rate; and
adjusting the number of filter taps based on the selected data rate;
wherein a mean square error associated with the echo canceller filter is reduced. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. In a communication network having a first modem in communication with a second modem over a communication channel, a system for adapting a filter length of an echo canceller filter based on data rate, the system comprising:
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a measuring module for measuring a plurality of approximate filter lengths at a plurality of data rates;
a fitting module for fitting a polynomial to a curve representing the approximate filter lengths at the plurality of data rates;
an input module for inputting a selected data rate to a function of the polynomial for generating an approximate number of filter taps for modeling an echo channel for the selected data rate; and
an adjusting module for adjusting the number of filter taps based on the selected data rate;
wherein a mean square error associated with the echo canceller filter is reduced. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A method for adapting a filter length of an echo canceller filter based on data rate, the method comprising the steps of:
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initiating a line probe session;
performing an abbreviated echo canceller training during the line probe session for determining a length of an echo tail;
estimating a number of taps for the echo canceller filter based on the abbreviated echo canceller training; and
adjusting the number of taps;
wherein a mean square error associated with the echo canceller filter is reduced. - View Dependent Claims (34, 35)
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36. In a communication network having a first modem in communication with a second modem over a communication channel, a system for adapting a filter length of an echo canceller filter based on data rate, the system comprising:
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a line probe module for initiating a line probe session;
a training module for performing an abbreviated echo canceller training during the line probe session for determining a length of an echo tail;
an estimating module for estimating a number of taps for the echo canceller filter based on the abbreviated echo canceller training; and
an adjusting module for adjusting the number of taps;
wherein a mean square error associated with the echo canceller filter is reduced. - View Dependent Claims (37, 38)
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Specification