The DBS

The DBS stands for Distributed Base Stations. It consist of following Parts:

•    BBU (Base Band Unit)
•    RRU (Remote Carrier Unit)

BBU Functions
•    The BBU3900 is a baseband processing unit. It processes the baseband signals of the base station.
•    The BBU3900 performs the following functions:
•    Provides ports for communication between the base station and the BSC or RNC.
•    Provides CPRI ports for communication between the BBU and the RFUs.
•    Provides USB(1) ports. A USB flash drive that stores required software and configuration data can be inserted into the USB port to perform the automatic base station upgrade.
•    Provides an OM channel between the base station and the LMT or the M2000 to operate and maintain the base station.
•    Processes uplink and downlink data.
•    Manages the entire dual-mode system in terms of OM and signaling processing.
•    Provides the system clock.

RRU3936 (Remote Radio Unit)

•    RRU Functions:-
•    Receives downlink baseband data from the BBU and sends uplink baseband data to the BBU.
•    Receives RF signals from the antenna system, down-converts the signals to intermediate frequency (IF) signals, amplifies the IF signals, and performs analog-to-digital conversion. The transmit (TX) channel filters downlink signals, performs digital-to-analog conversion, and up-converts RF signals to the TX band.
•    Multiplexes receive (RX) and TX signals on the RF channel, which enables these signals to share the same antenna path. It also filters the RX and TX signals.
•    Provides a built-in Bias Tee (BT). The built-in BT couples RF signals and OOK signals and transmits them through the TX/RX port A. The built-in BT also supplies power to the tower mounted amplifier (TMA).
•    The RRU can be powered by the AC/DC power module. In this case, this RRU is called AC RRU