A module of the distributed base station. It performs IF processing (digital I/Q modulation/demodulation, frequency up-/down-conversion, and DA/AD conversion) of the signals, RF processing, and duplex.
The RRU performs the following 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).
Here's a figure that shows the RRU ports:
The RRU consists of the high-speed interface unit, signal processing unit, power amplifier, duplexer, extension ports, and power module.
