A user equipment (UE) performs wireless communication by starting a scan of an absolute radio frequency channel number (ARFCN) configured for performing a narrowband communication. The UE determines, based on a spectral characteristic of a phase of a signal in the ARFCN, whether a cellular communication is deployed in the ARFCN. The UE may then terminate the scan of the ARFCN in response to the spectral characteristic of the phase of the signal in the ARFCN indicating that the cellular communication is deployed in the ARFCN. Alternatively, the UE may proceed with a synchronization signal search on the ARFCN in response to the spectral characteristic of the phase of the signal in the ARFCN indicating that the cellular communication is not deployed in the ARFCN.