Introduction to Base Transceiver Station (BTS) and Its Cards

LAB # 6

Engr. Mehran Mamonai

Appearance of BTS3012 Cabinet

Like a server cabinet

The BTS3012 cabinet is purple gray in color and vertical in appearance

Physical Structure of the BTS3012

The components are

1. Transmission subrack2. Common subrack3. DTRU subrack -04. Fan subrack5. DTRU subrack-16. DAFU subrack 7. Power distribution unit 8. Signal lightning protection subrack

Transmission sub-rack

located below the common sub-rack. Reserves space for the baseband unit

(BBU).› Such as SDH,› microwave transmission equipment

Common subrack

Common subrack The common subrack is installed below the

fan subrack. It holds the following parts:› DTMU › DEMU › DATU › DCSU › DCCU › DABB › DPTU

DTMU

Dual Transmission or Timing Management Unit

an entity for basic transmission and control in the BTS3012.

It works as a main controller. The DTMU is a mandatory module

inserted in slots 0 and 1 (from left to right)

DTMU (cont.)

DEMU

Dual Environment Monitoring Unit The DEMU performs the following

functions:› Monitors the environment information sent

from the smoke sensor, water sensor, temperature and humidity sensor, infrared sensor, and door control sensor

› Collects alarm information and reports it to the DTMU

DATU

Dual Antenna and TMA Control Unit

Controls the RET antenna Feeds power to the TMA

DCSU

Combined cabinet Signal connection Unit is placed in slot 5 of the common sub-rack

The DCSU is a mandatory board The DCSU performs the following functions:

› Transmits clock signals, data signals, and control signals between the main cabinet and the extension cabinet

› Transmits the clock signals, data signals, and control signals from the DTMU to the DTRU

DCCU

Cable Connection Unit is placed in slot 6.

The DCCU is a mandatory board. The DCCU performs the following

functions:› Transfers E1 signals › Transfers the control signals for the fans › Transfers the clock signals from the DAFU

subrack

DPTU

Packet transmission unit can be installed in slot 3 or 4

The DPTU is mandatory The DPTU performs the following

functions:› Provides the interface for Abis over IP › Provides the BTS with the convergence

function of a Hub › Provides the functionality of Clock Over IP

DTRU subrack

The DTRU subracks can hold up to nine DTRUs

DTRU

Double-Transceiver Unit (DTRU) is placed in the double-transceiver subsystem of the BTS.

One DTRU consists of two TRXs Baseband Processing Part

› The baseband processing part performs the following functions:

› Processing signaling, coding and decoding, interleaving and de-interleaving, modulation and demodulation

› Supports RF loop test and switchover of the faulty phase-locked loop

› Amplifying output power

DTRU (cont.)

RF Transmitting Part› The transmitting part of the RF signals performs the

following functions:› Modulates the baseband signals into RF signals and

performs up-conversion, filtering, and RF hopping › Amplifies and outputs the RF signals

RF Receiving Part› The receiving part of the RF signals performs the

following functions:› Demodulates the RF signals into baseband signals and

performs RF hopping › Divides the received RF signals and performs receive

diversity

Fan subrack

The fan subrack holds one fan box a fan monitoring board consists of four

fans. The fan monitoring board detects the

temperature at air inlets at bottom of the cabinet and automatically adjusts the fan speed

DAFU subrack

Antenna Front-end Unit The DAFU subrack can be configured

with› DDPU› DCOM› DFCU or DFCB.

DDPU

Dual-Duplexer Unit The DDPU performs the following

functions:› Provides lightning protection through the

ANT port › Detect VSWR alarms in the antenna system › Control the gains for the receive low noise

amplifier › Transmits multiple routes of RF signals

from the transmitter to the antenna

DCOM

Combining Unit The DCOM combines two routes of TX

signals from the DTRU, and then sends them to the DDPU

Power Distribution Unit

The power distribution unit consists of the › DC lightning arrester,› EMI filter,› PGND bar,› Busbar terminal socket (top)› Busbar (right)

Lightning protection subrack

The signal lightning protection subrack is installed on top of the cabinet. It is configured with the following boards:› DMLC › DELC › DSAC

DMLC

Monitor Signal Lightning-Protection Card The DMLC performs the following

functions:› Provides lightning protection for Boolean

input and output signals › Provides lightning protection for analog

signals that are transmitted from the smoke sensor, water sensor, door control sensor, infrared sensor, humidity and temperature sensor

DELC

E1 Signal Lightning-Protection Card The DELC performs the following

functions:› Provides lighting protection for E1 signals

DSAC

Signal Access Card

The DSAC performs the following functions:› Provides six Boolean alarm inputs › Provides lightning protection for BITS clock

signals