Method and apparatus for complementary cumulative distribution driven level convergence for spectrum sensing
First Claim
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1. A digital communications receiver comprising:
- at least one controllable amplifier stage operating based on a calculated error power; and
at least one analog-to-digital converter (ADC) for receiving a signal from the at least one controllable amplifier stage; and
at least one gain controller; and
wherein the at least one gain controller is configured to;
receive at least one input sample;
calculate a complementary cumulative distribution function (CCDF) for the input sample within a predetermined clipping level of the ADC;
calculate an error value, the error value being the difference between the calculated CCDF and a target CCDF; and
apply the error value to a multiplication function where it is multiplied with a value representing loop gain to generate a multiplication function output, the multiplication function output being input to a loop filter, the loop filter summing the multiplication function output and a previous value of a gain control value of the at least one gain controller thereby generating a control value as a function of the error value for adjusting the gain of the at least one controllable amplifier stage which in turn controls the ADC input signal power level to yield a desired probability of clipping without prior consideration of waveform characteristics.
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Abstract
A method for use in a digital communications receiver for controlling an input signal level (200) into an analog-to-digital converter (ADC) initially receives a sample sequence (201) where a threshold crossing rate is measured as a percentage samples of an input signal that exceed the threshold (203). The error between the measured threshold crossing rate and a desired reference threshold crossing rate is calculated (205) and an error signal is then utilized in a feedback loop to control the receiver gain such that the error is reduced (207).
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Citations
2 Claims
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1. A digital communications receiver comprising:
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at least one controllable amplifier stage operating based on a calculated error power; and at least one analog-to-digital converter (ADC) for receiving a signal from the at least one controllable amplifier stage; and at least one gain controller; and wherein the at least one gain controller is configured to; receive at least one input sample; calculate a complementary cumulative distribution function (CCDF) for the input sample within a predetermined clipping level of the ADC; calculate an error value, the error value being the difference between the calculated CCDF and a target CCDF; and apply the error value to a multiplication function where it is multiplied with a value representing loop gain to generate a multiplication function output, the multiplication function output being input to a loop filter, the loop filter summing the multiplication function output and a previous value of a gain control value of the at least one gain controller thereby generating a control value as a function of the error value for adjusting the gain of the at least one controllable amplifier stage which in turn controls the ADC input signal power level to yield a desired probability of clipping without prior consideration of waveform characteristics. - View Dependent Claims (2)
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Specification