Communication repeater and method for restoring synchronization thereof

A shared radio unit (RU) comprising:

• a receiver configured to receive a plurality of test signals from a plurality of external communication devices and then receive a plurality of downlink signals from the plurality of external communication devices;
• a digital signal processor configured to measure a delay time of each of the plurality of test signals, generate a reference signal based on the measured delay times of the plurality of test signals, and perform a delay synchronization process for the plurality of downlink signals based on the reference signal;
• and
• a transmitter configured to transmit the delay synchronized plurality of downlink signals,
• wherein the digital signal processor is configured to:
• determine whether the delay synchronized plurality of downlink signals have a synchronization error being not synchronized the same as the reference signal, and
• perform synchronization restoration for a downlink signal having the synchronization error among the delay synchronized plurality of downlink signals to be synchronized the same as the reference signal, based on a result of the determining.