Patent ID: 6996373

Claim:
A modulation detection method for a base station receiver in a wireless communications system, comprising receiving, at a base station receiver, a signal from user equipment over an air interface, continuously estimating, on the basis of information derived from said receiver signal, channel status information representing a condition of a transmission channel between the user equipment and the base station receiver, adaptively controlling, on the basis of the estimated channel status information, a modulation detection limit to be employed in deciding whether or not the received signal is modulated, calculating a cross-correlation vector between the received signal and a reference signal, calculating a mean value of the cross-correlation vector, determining a peak value in the correlation vector, scaling the mean value with a scaling factor, comparing the scaled mean value with the peak value, deciding, on the basis of the difference between the scaled and mean value and the peak value, whether or not the signal is modulated, and adaptively adjusting, on the basis of the estimated channel status information, the scaling factor.