Noise analysis in a communication system
First Claim
1. A method of allocating channels in a broadband communications system, comprising:
- at a receiver, identifying a time period during which a proposed channel is carrying no active transmission;
periodically scanning an upstream band and applying a fast fourier transform FFT algorithm on only a part of the upstream band, to estimate noise in the upstream band;
generating, from a delayed first sample of a received input signal over the proposed channel, a prediction of highly correlated noise in the input signalby accumulating the products of predictor coefficients and delayed sample values of the input signal;
subtracting the prediction of highly correlated noise from a second sample of a received input signal to determine residual noise enemy;
updating the predictor coefficients responsive to results of the subtracting step; and
allocating the proposed channel responsive to the estimated noise in the upstream band and the residual noise energy.
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Accused Products
Abstract
A system is provided to automatically estimate performance of a receiver for receiving input signals, the input signals having a carrier frequency and a baud rate, from a channel in a communication system and the effect of highly correlated noise cancellation on performance of the receiver, while no active transmission is occurring on the channel, comprising: a digital front end in the receiver for receiving samples of the input signals; a predictor coupled to the digital front end for predicting highly correlated noise in a second sample of the input signal; and a subtraction unit coupled to the predictor for subtracting the predictor output from the second sample to determine residual noise in the second sample. Other systems and methods are disclosed.
51 Citations
20 Claims
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1. A method of allocating channels in a broadband communications system, comprising:
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at a receiver, identifying a time period during which a proposed channel is carrying no active transmission; periodically scanning an upstream band and applying a fast fourier transform FFT algorithm on only a part of the upstream band, to estimate noise in the upstream band; generating, from a delayed first sample of a received input signal over the proposed channel, a prediction of highly correlated noise in the input signal by accumulating the products of predictor coefficients and delayed sample values of the input signal; subtracting the prediction of highly correlated noise from a second sample of a received input signal to determine residual noise enemy; updating the predictor coefficients responsive to results of the subtracting step; and allocating the proposed channel responsive to the estimated noise in the upstream band and the residual noise energy. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for allocating a channel in a communication system, comprising:
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a dedicated digital front end dedicated to upstream channel measurement and analysis, performance estimation and for receiving samples of the input signals, wherein the dedicated digital front end further comprising a plurality of stages including a plurality of decimating filters, at least one matched filter, down conversion and signal processing blocks and wherein the dedicated digital front end provides for periodically scanning an upstream band and implementing a fast fourier transform FFT algorithm on only a part of the upstream band to estimate noise in the upstream band; a predictor coupled to the dedicated digital front end for predicting highly correlated ingress noise from a first sample of an input signal received over a proposed channel during a time in which the proposed channel is carrying no active transmission; and a subtraction unit coupled to the predictor for subtracting the predictor output from a second sample of the input signal received over the proposed channel, to determine residual noise; analyzer circuitry for allocating the proposed channel responsive to the estimated noise in the upstream band and the residual noise. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification