In accordance with a first aspect of the present disclosure, a communication device is provided, comprising: a communication unit configured to execute a time-of-flight ranging session with an external communication counterpart; a clock offset measurement unit configured to measure a frequency offset of a device clock, wherein said device clock is configured to be used by the communication unit when said ranging session is executed; a processing unit configured to determine whether the measured frequency offset of the device clock has a predefined correlation with a frequency offset of a counterpart clock, wherein said counterpart clock is configured to be used by the external communication counterpart when said ranging session is executed. In accordance with a second aspect of the present disclosure, a corresponding method of operating a communication device is conceived. In accordance with a third aspect of the present disclosure, a corresponding computer program is provided.