A mobile communication base station system comprising: a donor unit connected to a baseband unit; a remote unit installed at a base station antenna side; and wherein the donor unit comprises a baseband signal processor including a digital signal processor adapted to process optical signals transmitted or received from the baseband unit, a wireless communication unit adapted to process a wireless communication signal between the baseband signal processor and the remote unit, and a synchronization and communication controller configured to generate a communication control signal and a synchronization signal according to a control command and a signal from the baseband unit, respectively, and wherein the remote unit comprises a service signal processor configured to process a Multiple Input Multiple Output,MIMO, signal transmitted or received from the base station antenna, a wireless communication unit configured to process a wireless communication signal between the service signal processor and the donor unit, and a synchronization and communication controller configured to process a synchronization signal and a communication control signal received from the donor unit, wherein the baseband signal processor of the donor unit is configured to receive a downlink signal from the baseband unit, configured to divide the downlink signal into a plurality of transmission channel signals, configured to convert the plurality of transmission channel signals into a plurality of predetermined Radio Frequency,RF, band signals, respectively, configured to shift frequencies of the predetermined RF band signals by a predetermined amount, and configured to output the resultant RF band signals, and the wireless communication unit of the donor unit is configured to synthesize signal output resultant from the baseband signal processor, configured to convert the signal into a predetermined frequency band, and configured to transmit the predetermined frequency band signal by wireless communication. a donor unit connected to a baseband unit; a remote unit installed at a base station antenna side; and wherein the donor unit comprises a baseband signal processor including a digital signal processor adapted to process optical signals transmitted or received from the baseband unit, a wireless communication unit adapted to process a wireless communication signal between the baseband signal processor and the remote unit, and a synchronization and communication controller configured to generate a communication control signal and a synchronization signal according to a control command and a signal from the baseband unit, respectively, and wherein the remote unit comprises a service signal processor configured to process a Multiple Input Multiple Output,MIMO, signal transmitted or received from the base station antenna, a wireless communication unit configured to process a wireless communication signal between the service signal processor and the donor unit, and a synchronization and communication controller configured to process a synchronization signal and a communication control signal received from the donor unit, wherein the baseband signal processor of the donor unit is configured to receive a downlink signal from the baseband unit, configured to divide the downlink signal into a plurality of transmission channel signals, configured to convert the plurality of transmission channel signals into a plurality of predetermined Radio Frequency,RF, band signals, respectively, configured to shift frequencies of the predetermined RF band signals by a predetermined amount, and configured to output the resultant RF band signals, and the wireless communication unit of the donor unit is configured to synthesize signal output resultant from the baseband signal processor, configured to convert the signal into a predetermined frequency band, and configured to transmit the predetermined frequency band signal by wireless communication.