System and method for synchronizing at least one small cell with at least one macro cell in a heterogeneous network. The method comprises the at least one small cell triggering an NB-IoT modem for a clock reference signal. The NB-IoT modem detects a first synchronization signal and a second synchronization signal, the first synchronization signal and the second synchronization signal being transmitted by at least one NB-IoT cell connected to the at least one macro cell. The NB-IoT modem synchronizes the at least one small cell with the at least one macro cell based on at least one of the first synchronization signal and the second synchronization signal.