Wireless communication device and method therein for time synchronization in a wireless communication network

A wireless communication device for time synchronization in a wireless communication network, wherein the wireless communication device is configured to:

• determine a first timing, tc, by being configured to perform a coarse time synchronization based on a synchronization signal received by the wireless communication device, wherein the received synchronization signal is sampled either in an original sampling rate or a reduced sampling rate;
• and
• determine a second timing, tf, by being configured to perform a fine time synchronization based on the determined first timing and the received synchronization signal, wherein
• the wireless communication device is configured to determine the first timing by performing steps comprising:
• selecting a number of timing offset, m, values with a granularity corresponding to or smaller than a length of the shortest cyclic-prefix supported by the synchronization signal;
• obtaining channel estimates by performing channel estimations on the received synchronization signal for each selected timing offset value in frequency domain;
• transforming the channel estimates in frequency domain to time domain;
• calculate channel powers, Pm, for each selected timing offset value based on its channel estimates in time domain;
• and
• determining the first timing based on the calculated channel powers.