Patent ID: 8149863

Claim:
A method of controlling access to a wireless communications medium, the method comprising: sampling radio frequency activity on the medium; autocorrelating samples to produce a first autocorrelation value via a first autocorrelator, wherein the first autocorrelation value is indicative of autocorrelation computed with a first delay matching periodicity of a signal of interest; monitoring the first autocorrelation value to determine whether the first autocorrelation value is indicative of the signal of interest; autocorrelating samples to produce a second autocorrelation value via a second autocorrelator, wherein the second autocorrelation value is indicative of autocorrelation computed with a second delay different from the first delay; monitoring the second autocorrelation value to determine whether the second autocorrelation value is indicative of an interferer signal, wherein the interferer signal is a noise signal; preventing transmission of a radio frequency transmit signal via radio frequency transmission control circuitry on the medium in response to the first autocorrelation value indicating activity on the medium includes the signal of interest when the second autocorrelation value indicates activity on the medium does not include an interferer signal, wherein the radio frequency transmission control circuitry comprises at least one of the first autocorrelator and the second autocorrelator: generating a correlation value via an accumulator circuit of one of the first autocorrelator and the second autocorrelator; generating a complex value based on the correlation value via a summation circuit of the one of the first autocorrelator and the second autocorrelator; determining a magnitude of the complex value via a magnitude computation circuit of the one of the first autocorrelator and the second autocorrelator; and generating one of the first autocorrelation value and the second autocorrelation value based on the magnitude via a filter of the one of the first autocorrelator and the second autocorrelator.