Introduction To Rf Modules; Btrm; Overview - Huawei Airbridge BTS3612A-1900 Technical Manual

Technical Manual
Airbridge BTS3612A CDMA Base Station
In forward link, it performs power adjustable up-conversion and linear power
amplification to the modulated transmission signals, filtering the transmission signals to
meet the corresponding air interface standard.
In reverse link, it filters the signals received by the BTS antenna to suppress out-band
interference, and then performs low-noise amplification, noise factor adjustable
frequency down-conversion, and channel selective filtering.

3.1.2 Introduction to RF Modules

The RF subsystem is composed of RF modules. Figure 8-3 shows the RF subsystem in
full configuration.
RF modules include:
BTRM: Complete the modulation/demodulation of baseband signal and up/down
conversion.
BHPA: Complete the high-power linear amplification of transmitting carrier signals.
DFU: Complete the wave filtering and duplex isolation of one main
transmitting/receiving signal, and the wave filtering of diversity receiving signal. It
is one of the RF front-end modules.
DDU: Complete the isolation and duplex filtering of two receiving/transmitting
signals. It is one of the RF front-end modules and is not equipped with the
combiner function.
CDU: Complete the combination and wave filtering of two transmitting signals,
duplex isolation of main transmitting and receiving signals, and the wave filtering
of diversity receiving signal. It is one of the RF front-end modules.
RLDU: Complete the low noise amplification and dividing of receiving signals.
Besides the above modules, the backplane of RF module and the RF fan module will
also be introduced in this chapter.

3.2 BTRM

3.2.1 Overview

In reverse link, the BTS Transceiver Module (BTRM) receives the main/diversity RF
signals from the RLDU, and then changes the RF signals into baseband signals
through down-conversion, wave filtering and multiplexing. Finally the BTRM sends the
baseband signals to the baseband subsystem through the BRDM.
In forward link, the BTRM receives the baseband signals from the BRDM, then
changes the baseband signals into RF signals through de-multiplexing, wave filtering
and up-conversion. Finally the BTRM sends the RF signals to the RF subsystem
through the RF front module such as CDU.
Chapter 3 Radio Frequency Subsystem
3-2
System Principle