A technique for performing a clear channel assessment (CCA) in an unlicensed radio frequency (RF) spectrum is described. The CCA is performed for transmitting data (420) according to a first radio access technology (RAT) in coexistence with a second RAT. As to a method aspect of the technique, signals (411) are received in the unlicensed RF spectrum. The received signals (411) are processed according to an operating state. The processing in a first operating state (402) causes a first delay that is greater than a second delay caused by the processing in a second operating state (404). The operating state depends on the presence of data (420) to be transmitted according to the first RAT in the unlicensed RF spectrum. The CCA is performed based on the processed signals.