A network node of a wireless communication network comprises a receiver receiving an input signal from a remote transmitter of the wireless communication system via a transmission channel. A signal to noise ratio calculator is arranged to calculate a signal to noise ratio of the received input signal. A soft bit normalizer is arranged to determine a plurality of normalized soft bits using the input signal. A primary detector is arranged to detect a discontinuous transmission on the transmission channel using the plurality of the normalized soft bits and the signal to noise ratio, and if a discontinuous transmission on the transmission channel is detected, generate a DTX-decision or else trigger a refinement detector. The refinement detector is arranged to decode the normalized soft bits and to generate a further decision about whether the signal indicates a discontinuous transmission on the transmission channel using the decoded normalized soft bits.