With the development of mobile communication technology, more and more new communication technologies(such as 4G) are being used nowadays. As a result, telecom operators have to run multiple systems simultaneously and provide multi-system services(2G/3G/4G) in one coverage area, resulting in the difficulty of installation and transmission of equipments. For the above mentioned reasons, Multi-Band Active DAS is designed to solve the problems of weak mobile signal in the place that is far away from the Base Transceiver Station(BTS) and has fiber optic cable network underground. The system consists of two parts: Master Unit and Remote Unit. The Master unit captures the BTS signal via direct coupler closed to BTS, then converts it into optic signal and transmits the amplified signal to the Remote Unit via fiber optic cable. The Remote unit will reconvert the optic signal into RF signal and provide the signal to the areas where network coverage is inadequate. And the mobile signal is also amplified and retransmitted to the BTS via the opposite direction.
