Patent ID: 7831414

Claim:
An apparatus for detecting a presence of a signal in a communication channel, comprising: a processor configured to select one or more peak samples of two or more fields of a sampled signal, the processor further configured to determine one or more absolute values of the one or more peak samples of the two or more fields, the processor further configured to superimpose the one or more absolute values of the one or more peak samples of the two or more fields, the processor further configured to combine the one or more absolute values that fall within a predetermined window to produce a peak value, the processor further configured to compare the peak value with a threshold to determine a presence of a signal in the communication channel, the processor further configured to correlate a known pattern with the two or more fields of the sampled signal to provide the one or more peak samples and other samples that match the known pattern, wherein the processor comprises a correlator configured to correlate the known pattern with the two or more fields of the sampled signal to provide the one or more peak samples and the other samples, wherein an input and an output of the correlator have the following relationship: y ⁡ ( n ) = ∑ i = 0 N - 1 ⁢ r ⁡ ( n - i ) ⁢ x ⁡ ( i ) wherein y(n) represents an output of the correlator, r(n−i) represents an input of the correlator, the input being a digital signal, x(i) represents a value in the correlator, N is an integer, n is an integer, and i is an integer that varies from 0 to N−1.