Detecting presence/absence of an information signal
First Claim
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1. A method for detecting a presence of an information signal in a received signal, comprising:
- receiving an electrical signal;
correlating the received signal with a spreading code;
processing the correlated signal to produce a sequence of power values;
for a most recent power value, updating a mean power value over a plurality of power values in the sequence;
determining a range of mean power values defined by the updated mean power value bounded by a selected multiple of a variance of the plurality of mean power values according to a selected statistical distribution; and
comparing the range of mean power values with a signal threshold value;
wherein the presence of an information signal in the received signal is detected responsive to the comparing step indicating that the range of mean power values exceeds the signal threshold.
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Abstract
A method and apparatus for detecting the presence of an information signal in received inputs. Inputs are received and an expected variance of the received inputs is determined based on an assumed statistical distribution of power values. Using the determined expected variance of the received inputs, a first hypothesis is tested that the received inputs include an information signal to detect a presence of the information signal.
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Citations
17 Claims
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1. A method for detecting a presence of an information signal in a received signal, comprising:
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receiving an electrical signal; correlating the received signal with a spreading code; processing the correlated signal to produce a sequence of power values; for a most recent power value, updating a mean power value over a plurality of power values in the sequence; determining a range of mean power values defined by the updated mean power value bounded by a selected multiple of a variance of the plurality of mean power values according to a selected statistical distribution; and comparing the range of mean power values with a signal threshold value; wherein the presence of an information signal in the received signal is detected responsive to the comparing step indicating that the range of mean power values exceeds the signal threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 10, 11, 12)
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8. A method as claimed in 7, wherein the noise threshold is a constant.
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9. A method as claimed in 7, wherein the noise threshold is an expected mean of the inputs if there is no signal.
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13. An apparatus comprising:
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a power converter configured to receive input signal values, and process the received input signal values to provide a sequence of power values; and processing circuitry, for detecting presence of an information signal within a received signal corresponding to the input signal values, configured to for a most recent power value, update a mean power value over a plurality of power values in the sequence; determine a range of mean power values defined by the updated mean power value bounded by a selected multiple of a variance of the plurality of mean power values according to a selected statistical distribution; and compare the range of mean power values with a signal threshold value; wherein the presence of an information signal in the received signal is detected responsive to the range of mean power values exceeding the signal threshold. - View Dependent Claims (14, 15, 16, 17)
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Specification