A method for estimating relative time offset and relative clock skew between a first radio transceiver and a second radio transceiver, said method comprising: receiving coarse information of the relative time offset and relative clock skew; receiving and transmitting signals at sequences of frequencies by switching of frequencies by the first radio transceiver in synchronization with a switching of frequency by the second radio transceiver, wherein switching of frequencies is performed by coherent frequency switching, and wherein sequences of frequencies include sub-sequences of increasing frequency values and decreasing frequency values, respectively, performing phase measurements for each frequency; determining weighted average phase difference values between sequential frequency values; and determining a fine estimate of the relative time offset and relative clock skew based on the weighted average phase difference values.