Various communication systems may benefit from an accurate detection method. The method may include determining correlation values between a first sequence of samples and at least one pre-defined sequence, detecting whether at least one first peak exists by comparing the correlation values with at least one first detection threshold. If the at least one first peak exists, the method may further include performing summing of at least a subset of the correlation values and detecting whether at least one second peak exists by comparing the summed correlation values with a second detection threshold.