A method is provided for performing a clear channel assessment in a
wireless network. The method involves first listening for channel energy
on a wireless channel. Whatever channel energy is heard over the wireless
channel is demodulated into non-synchronized in-phase and
non-synchronized quadrature phase components. Each of the
non-synchronized in-phase and non-synchronized quadrature phase
components are squared, and then the non-synchronized in-phase component
is multiplied by the non-synchronized quadrature phase component to
produce an I-Q product. The sum of the squared non-synchronized in-phase
component, the inverse of the squared non-synchronized quadrature
component, and double the I-Q product is determined as a clear channel
assessment input value. A carrier signal detection function is then
performed on the clear channel assessment input value to produce a clear
channel assessment output value, which is used to determine whether a
signal is present in the wireless channel.