Patent ID: 7864884

Claim:
A method comprising: receiving a signal through a radio channel, the signal comprising digital samples, wherein a sampling rate of the digital samples is according to a bandwidth of the received signal; calculating a sample shift value according to a ratio between the known bandwidth of a desired signal being detected and the total bandwidth of the received signal, wherein the bandwidth of the desired signal is known to be lower than the bandwidth of the received signal; comparing the digital samples of the received signal with digital samples of a reference signal representing the desired signal, by applying different sample shifts between the two signals in the comparison so as to shift the two signals with respect to each other, the length of the sample shifts being defined by the calculated sample shift value to be higher than one sample when the bandwidth of the desired signal is lower than the bandwidth of the received signal, and by correlating the digital samples of the received signal with the digital samples of a reference signal with the different sample shifts; and determining, on the basis of whether or not at least one of the correlations results in a match between the received signal and the reference signal, whether or not the received radio signal comprises the desired signal.