Baseband refers to the original frequency range of a transmission signal before it is modulated. A baseband unit is a unit that processes the baseband signals in telecommunication systems. A base station is divided into two units as RRU ( remote radio unit) which is a RF processing unit and a baseband unit. RRU is connected to the BBU via optical fiber links. A BBU has a modular design , small size, low power consumption and it can be easily deployed.
A BBU comprises a digital signal processor to process forward voice signals for transmission to a mobile unit and reverse voice signals received from the mobile unit. The BBU acts as a centralized hub of the base station, it processes UL and Dl data traffic and controls the RRU functionality. BBU compliments 5G by providing more flexible load management, use cases optimization and flexibility. Control unit/data unit functions can also be moved closer to the radio unit for a number of use cases with high bandwidth demands and fixed user locations.