huawei gsm-r bts3900a hardware structure-20141204-issue4 0

2008-05

www.huawei.com

HUAWEI Confidential

Security Level: Internal Use

HUAWEI GSM-R BTS3900A

Hardware Structure

ISSUE4.0

Wireless Case and training

HUAWEI TECHNOLOGIES Co., Ltd. HUAWEI Confidential Page 2

The BTS3900A developed by Huawei is an outdoor macro

BTS that performs the same tasks as the BTS3900. The

BTS3900A mainly consists of the BBU and DRFUs. Compared

with traditional BTSs, the BTS3900A features simpler structure

and higher integration.


Know the functions and features of BTS3900A

Master the Hardware structure and function of BTS3900A

Master the Network topologies of BTS3900A


BTS3900A Product DescriptionV301R013)

BTS3900A Hardware DescriptionV301R013)

BTS3900A Installation GuideV301R013)

APM30 User Guide


Chapter 1 BTS3900A System Description

Chapter 2 BTS3900A Hardware Structure

Chapter 3 BTS3900A Network Topology


Location

MS

PSTN

ISDN PSPDN

Um Interface

BTS3900A

BTS3900A

BTS3900A

BTS

OMC

HLR/AUC/EIR

BSC

MSC/VLR

SMC/VM

A Interface

MAP

TUP,ISUP MS

MS

MS: Mobile Station BTS: Base Transceiver Station BSC: Base Station Controller

HLR: Home Location Register AUC: Authentication Center EIR: Equipment Identity Register

MSC: Mobile Switching Center VLR: Visitor Location Register SMC: Short Message Center

VM: Voice Mailbox OMC: Operation and Maintenance Center DBSDistributed Base Station




Chapter 3 BTS3900A Network Topology


Component

Board/

Module

Full Spelling Parts Configured in a Single Cabinet

Full Configuration Minimum Configuration

UEIU Universal Environment Interface Unit 1 0

GTMU GSM Transmission & Management Unit for

BBU

1 1

UELP Universal E1/T1 Lightning Protection unit 1 0

UBFA Universal BBU Fan unit type A (2U) 1 1

UPEU Universal Power and Environment

interface Unit

2 1

DRFU Double Radio Filter Unit 6 1

DCDU Direct Current Distribution Unit 2 2

FMUA Fan Environment Monitor 1 1

FAN Fan Module 2 2

- Door Status Sensor 1 1

- Smoke Sensor 1 1


Section 1 System Structure

Section 2 PD Cabinet Hardware Component

Section 3 RF Cabinet Hardware Component

HUAWEI TECHNOLOGIES Co., Ltd. HUAWEI Confidential

Outdoor BTS3900A Ver.D cabinet

Page 10

BTS3900A (AC) Ver,D BTS3900A (DC) Ver,D


Outdoor IBBS200D/IBBS200T Ver.D

cabinet

Page 11

IBBS200D Ver,D IBBS200T Ver,D


BTS3900A Local Structure





Section 4 DRFU Work Mode


Power Distribution Cabinet Hardware Components

BBU

Power Frame (AC/DC)

APMI

AFMU

PDU

Heater

Battery

Sensors


BBU Logical Structure


BBU Hardware Structure

The BBU is a small box with all the external ports on the front panel.

The BBU3900 boards consist of the UEIU, GTMU, and UELP; the BBU3900

modules consist of the UBFU and the UPEU.


BBU Board--GTMU

The GSM transmission, timing, and management unit for BBU (GTMU)

controls and manages the entire BTS. It provides interfaces related to

the reference clock, power supply, OM, and external alarm collection.

The GTMU performs the following functions: Controls, maintains, and operates the BTS.

Supports fault management, configuration management, performance

management, and security management.

Supports the monitoring of the fan module and power supply module.

Distributes and manages BTS3900 clock signals. Provides clock input for testing.

Provides port for terminal maintenance.

Supports four E1 inputs.

Provides CPRI ports for communication with the RF modules .


BBU Board--GTMU

Ports on the Panel

Port Type Description

CPRI0CPRI5

SFP

connector

Provides the input and output of optical and electrical transmission

signals

ETH RJ45

connector

Local maintenance and commissioning

FE0 RJ45

connector

A reserved port that performs the following function:

Connects the BBU to a routing device in the equipment room through

the Ethernet cable to transmit network information

FE1 DLC

connector


Connects the BBU to a routing device in the equipment room through

the optical cable to transmit network information

USB USB

connector


Automatically upgrades the software through the USB disk

TST USB

connector

Testing of the output clock signals by using a tester

E1/T1 DB26 male

connector

Provides the input and output of the four E1/T1 signals between the

GTMU and the UELP or between the GTMU and the BSC.


BBU Board--GTMU LEDs on the board

LED Color Status Description

RUN Green On The board is faulty.

Off There is no power supply or the board is

faulty.

Blinking once every two seconds The board is operational.

Blinking once every four seconds The OML link is abnormal.

Blinking four times per second The board is loading software.

ALM Red On A fault occurs in the running board.

Off An alarm is not generated.

ACT Green On The board is operational.

Off The board is faulty.

LIU0LIU3 Green On A local E1/T1 alarm is generated.

Blinking four times per second A remote E1/T1 alarm is generated.

Off This link is not used or the alarm is cleared.

CPRI0CPRI5

Green On The CPRI link is functional.

Red On The reception of the optical module is

abnormal and an alarm is generated.


BBU Board--GTMU

DIP Switch

DIP Switch DIP Status Description

1 2

SW1 ON ON The E1 impedance is set to 75 .

OFF ON The E1 impedance is set to 120 .

ON OFF The T1 impedance is set to 100 .


1 2 3 4

SW2 ON ON ON ON The E1 cable is grounded.

OFF OFF OFF OFF The E1 cable is not grounded.


BBU Board--GTMU

DIP Switch

DIP

Switch

DIP Status Description

1 2 3 4

SW4 ON ON ON ON The E1 link can be bypassed.

OFF OFF OFF OFF The E1 link cannot be bypassed.

DIP

Switch

DIP Status Description

1 2 3 4

SW5 ON ON ON ON The E1 link cannot be bypassed.

OFF ON ON OFF The E1 link of the Level 1 cascaded BTS can be bypassed.

ON OFF ON OFF The E1 link of the Level 2 cascaded BTS can be bypassed.

OFF OFF ON OFF The E1 link of the Level 3 cascaded BTS can be bypassed.

ON ON OFF OFF The E1 link of the Level 4 cascaded BTS can be bypassed.

OFF ON OFF OFF The E1 link of the Level 5 cascaded BTS can be bypassed.


BBU Module--UBFA

The universal BBU fan unit type A (2U) (UBFA) communicates with the

GTMU to regulate the temperature, adjust the fan speed, and report

alarms. The UBFA module is hot swappable.

LED Color Status Description

STATE Green Blinking twice

per second

The board is not securely

connected. An alarm is not

generated.

Red On An alarm is generated.

Green Blinking once

every two

seconds

The board operates normally.


BBU Module--UPEU

The universal power and environment interface unit type A/B ((UPEU)

supports the 48 V DC(UPEA)/+24V(UPEB) power input, supplies

power to the boards, modules, and fan in the BBU, and provides

access to multiple environment monitoring signals.

The UPEU performs the following functions:

Supplies power to the boards, modules, and fans.

Introduces environment monitoring signals to the BBU.

Reports fault signals, in-position signals, and version information

associated with the boards and modules.


BBU Module--UPEU

Ports on the Panel

Label Connector Description

PWR 3V3 +24 V/-48 V DC power input

EXT-ALM1 RJ45 Transmitting eight dry contact alarms

EXT-ALM0 RJ45

MON1 RJ45 Transmitting two RS485 environment monitoring signals

MON0 RJ45


BBU Board--UEIU

The universal environment interface unit (UEIU) supports multiple

environment monitoring signals. The UEIU supports eight Boolean

alarm signals and two RS485 environment monitoring signals.

The UEIU is optional. It is configured when the environment interfaces

are insufficient.


BBU ModuleUEIU

Ports on the Panel

Label Connector Description

EXT-ALM1 RJ45 Transmitting eight dry contact alarms

EXT-ALM0 RJ45

MON1 RJ45 Transmitting two RS485 environment monitoring signals

MON0 RJ45


BBU Board--UELP

The universal E1/T1 lightning protection unit (UELP) provides lightning

protection for four E1/T1 signals.

Port Type Cable Description

INSIDE DB25 male

connector

E1 transfer cable

of the BBU

Transfers the four E1/T1 signals between the UELP

and the GTMU

OUTSIDE DB26 male

connector

E1/T1 cables of

the BBU

Provides the input and output of the four E1/T1

signals between the BBU and the BSC

The UELP has one DIP switch, which is used to set the impedance on the

E1/T1 port. There are four DIP bits on the DIP switch.


1 2 3 4

S1 ON ON ON ON The E1 impedance is set to 75 ohms. The E1

is grounded (unbalanced mode).

OFF OFF OFF OFF Other modes


BBU Cable connection

The BBU3900 cables are classified into the PGND cable, -48VDC

power cable, E1/T1 cable, E1 transfer cable, environment monitoring

signal cable, CPRI signal cable between the BBU and the RRU, and

BBU monitoring signal cable.

The cable connection relations of the BBU are as follows:


BBU Cables

The cables figure of the BBU

-48VDC power cables E1 transfer cable

FE cable CPRI optical cable


BBU Cables

The cables figure of the BBU

(1)RJ45 Connector (2) Cord end terminal

Monitoring signal cable between the APM and the BBU


Power Subrack (AC/DC)

Power Subrack (AC/DC) connects with external 220VAC power input.

The 220VAC power is converted to -48VDC power and then connects

with DCDU module.

PMU (Power and Environment Monitoring Unit) module manages the power

supply and batteries. The DPMU is the core of the power monitoring system.

PSU (Power Supply Unit) module Converts the 220 V AC power into the -48 V

DC power.

Wiring unit is used to connect with 220VAC power input cable and connects the

cable from DCDU module.


Power Subrack (AC/DC)PMU Module The DPMU manages the power supply and batteries. The DPMU is

the core of the power monitoring system.

The DPMU performs the following functions:

Communicates with the central processing unit through the RS232/RS422

serial port.

Manages the power system and the battery charging and discharging.

Detects and reports water damage alarms, smoke alarms, door status

alarms, and standby Boolean value alarms; reports ambient humidity and

temperature, battery temperature, and standby analog values.

Detects power distribution and reports alarms, and also reports dry

contact alarms.

(1) LEDs (2) Power supply test ports

(3) RS232/RS422 ports (4) Battery control switch

(5) COM port - (1) Backplane port (2) DIP switch


Power Subrack (AC/DC)PMU Module Ports on the panel

Ports Function

RS232/RS422

port

Used in communication with the central processing unit.

Battery switch The battery switch has two control ports ON and OFF, which are used for

switching on and switching off the battery.

Press and hold the port ON for 5-10 seconds to switch on the battery.

Press and hold the port OFF for 5-10 seconds to switch off the battery.

Power supply

test port

Two power supply test holes -48V and 0V are available for measurement

through an ordinary multi-meter.

COM port Used in connection to the external signal transfer board.

Backplane

port

Used in connection to the backplane.


Power Subrack (AC/DC)PMU Module LED on the module

LED Color Status Meaning

RUN Green Blinking once every

two seconds

The module is functional, and the communication with

the central processing unit is normal.

Blinking four times

per second

The module is functional, but the communication with

the central processing unit fails.

Steady on/steady off The module is faulty (not in the power-on self-check

state).

ALM Red On The following alarms are generated:

Mains over-voltage or under-voltage alarm

Busbar over-voltage or unde-rvoltage alarm

Battery charging over-current alarm

Battery shutdown alarm

Batteries loop failure alarm

Ambient temperature alarm

Ambient humidity alarm

Water damage alarm

Smoke alarm

Power module alarm

Load shutdown alarm

Off No alarm is generated.


Power Subrack (AC/DC)PMU Module DIP Switch

Bit 3 Bit 2 Bit 1 Bit 0 Monitoring Address

0 0 0 0 0000

0 0 0 1 0001

0 0 1 0 0010

0 0 1 1 0011

0 1 0 0 0100

0 1 0 1 0101

0 1 1 0 0110

0 1 1 1 0111

1 0 0 0 1000

1 0 0 1 1001

1 0 1 0 1010

1 0 1 1 1011

1 1 0 0 1100

1 1 0 1 1101

1 1 1 0 1110

1 1 1 1 1111


Power Subrack (AC/DC)PSU Module The PSU (AC/DC) has the following functions:

Converts the 220 V AC power into the -48 V DC power

Monitors alarms related to module faults (such as output

overvoltage, no output, and fan faults), alarms related to

module protection (such as overtemperature protection,

and input overvoltage/undervoltage protection), and power

failure alarm

Monitors the charging and discharging of the batteries

LED Color Status Meaning

Power input

LED (top)

Green On Normal.

Off There is no AC power input or the fuse is damaged.

Power

protection

LED (middle)

Yellow Off Normal.

On Power protection for the PSU is being triggered, for example,

upon input undervoltage/overvoltage or overtemperature.

Power failure

LED

(bottom)

Red Off Normal.

On Irrecoverable fault occurs inside the PSU. For example, the

fault can be output overvoltage, no outputs, or fan fault.


Power Subrack (AC/DC)Wiring Unit The power subrack works in the following environment:

The wiring unit is connected to the external power supply through the terminals

L and N wires, and leads the power to the PSU (AC/DC) through the

backplane.

The PSU (AC/DC) converts the input AC power into the -48 V DC power.

The DPMU monitors the operating status of the PSU (AC/DC).

The wiring unit provides -48 V DC power outputs through LOAD1(-), LOAD2(-),

and RTN(+).

(1) PMU Module (2) PSU Module (AC/DC) (3) Wiring Unit


APMI Board The APMI board refers to APM Power Monitor unit Interface board. The

APMI board is located at the upper left corner of the APM30 cabinet,

and performs the following functions:

Transfers the APM30 serial port communication signals, Boolean

input/output signals, and EMI signals.

Protects the dry contact input/output signals and RS485 signals

(connected to the BBU/BTS)


APMI Board Port on the panel

Port Connector Type Quantity Function

RS422 RJ45 connector 1 Connecting the monitoring signal cable

between the PMU and the APMI

TX+, TX-,

RX+, RX-

2-pin molex connector 2 Connecting the monitoring signal cable

between the APMI and the BBU

IN1-IN3 2-pin molex connector 3 Connecting the dry contact alarm input cable

OUT1 2-pin molex connector 1 Connecting the optical coupling alarm output

cable


AFMU Board The AFMU board refers to APM Fan Monitor unit Interface Board. The

AFMU board is located at the upper right corner of the APM30 cabinet,

and performs the following functions:

Provides DC power supply to the APMI and AFMU boards through the DC

power port

Supplies DC power to the two fans at the top of the cabinet and reports the

alarms of the fans

Reports the alarms of the internal ambient temperature sensor, air inlet

temperature sensor, and air outlet temperature sensor

The alarm signals of the AFMU board is transported to the APMI board

through

the signal transfer cable and then is reported to the BBU.


AFMU Board Ports and LED on the Panel

SN Port Function

1 ALM Connecting the monitoring signal

cable between the AFMU and the

APMI

2 DC

INPUT

Connecting the DC power cable

of the AFMU

LED Silkscreen Color Status Description

Operation

LED

RUN Green ON steady About 1 minute after the AC or DC power-on

Blinking for 1s ON

and 1s OFF

The system is working properly.

Blinking for 0.125s

ON and 0.125s OFF

The serial port communication is disrupted.

The other communication is normal.

OFF steady The system is not powered on.

Alarm LED ALM Red ON steady An alarm is generated.

OFF steady No alarm is generated, or the system is not

powered on.


PDU Module The PDU (short for Power Distribution Unit) performs AC or DC power

distribution.

The AC distribution functions of the PDU are as follows:

Supplies two AC power outputs with the maximum current of 10 A to the heaters

of the power cabinet and the heating film of the battery cabinet.

Reports the surge protection alarms of the AC input power .

The DC distribution functions of the PDU are as follows:

Provides 10 DC power outputs to meet the DC power requirements of t

he distributed base station or the separated base station

Reports the surge protection alarms of the DC output power


PDU Module The port on the panel

SN Description

1 AC wiring terminals

For the 110 V dual-live-wire input, use L2

For the single-phase 220 V/three-phase 220 V input, use N1 and N2

2 AC wiring terminals

For the 110 V dual-live-wire input, use L1

For the single-phase 220 V/three-phase 220 V input, use L1, L2 and L3

3 AC output wiring terminals (Lout1, Lout2)

4 AC output wiring terminals (Nout1, Nout2)

5 AC input MCB

6 AC output MCB (controls the power supply to the heating film or heaters)

7 DC output MCBs (SW0-SW9)

8 DC output wiring terminals (LOAD0-LOAD9)


Heater

The heater functions in the low-temperature environment to provide

suitable working temperature for the batteries in the power cabinet or

transmission cabinet. When the working temperature is lower than the

temperature specification for the battery, the battery capacity declines.

So the heater is installed in the battery cabinet to provide the optimal

working temperature for the batteries.

The technical specifications of the heater are as follows:

A heater keeps the cabinet temperature higher than 10. When the internal

temperature of the cabinet is lower than 5, the heater starts to work; when

the internal temperature is higher than 15, the heater stops working.

The maximum power consumption of a 220 V heater is 300 W.


Battery

The power cabinet can house 1 to 3 groups of -48 V 12 AH batteries,

which can form the -48 V 12 AH battery group system, the -48 V 24 AH

system, or the -48 V 36 AH system. The details are as follows:

The -48 V 12 AH or -48 V 24 AH battery group is installed in the 3 U space

at the bottom, and the remaining 5 U space can be used to install the user

devices.

The -48 V 36 AH battery group is installed

in the 6 U space at the bottom, and the

remaining 2 U space can be used to install

the user devices.


Sensors Door Status Sensor

The door status sensor is made up of two parts, the magnet part and the switch part.


Sensors Temperature Sensor

The temperature sensors of the APM30 consist of the air inlet temperature

sensor, internal ambient temperature sensor, and the air outlet temperature sensor.





Section 4 DRFU Work Mode


RF Cabinet Hardware Components

DRFU

DCDU

FAN Unit

FMUA

Battery

Door Sensor


MRFUd Logical Structure

The MRFUd performs modulation and demodulation between baseband

signals and RF signals, processes data, and combines and divides

signals.

The MRFUd consists of the high-speed interface unit, signal processing

unit, power amplifier, and dual-duplexer.


Appearance and Interfaces

Page51

CPRI interface capacity item quota

CPRI interface quantity 2

CPRI interface rate 1.25Gbit/s or 2.5Gbit/s

supporting CPRI networking

mode

binary star mode

Interface type

Connectors type

quantity

instruction

RF interface

DIN

2

for connecting the antenna feeder system

RF receipt signal interconnection interface

QMA female

2

for RF module interconnection

CPRI interface

SFP female

2

for connecting to BBU3900

power interface

3V3

1

-48V power input

monitor interface

RJ45

1

monitor and maintenance


MRFUd Board

LEDs on the Board

LED Status Meaning

RUN On The power input is normal, but the BBU is faulty.

Off There is no power supply or the module is faulty.

Blinking once every two

seconds

The module is functional.

Blinking four times per second The module is loading software or is not started.

ALM On A fault alarm is generated.

Off No alarm is generated.

ACT On The module is functional and is correctly

connected to the BBU.

Off The connection with the BBU is not established.


seconds

The MRFUd is being tested on the Site

Maintenance Terminal.


MRFUd Board

LEDs on the Board

LED Status Meaning

VSWR Off (red) No VSWR alarm is detected.


seconds (red)

The VSWR alarm is generated on only the ANT2

port.

Blinking four times per second

(red)

The VSWR alarms are generated on the ANT1 and

ANT2 ports.

On (red) The VSWR alarm is generated on only the ANT1

port.

CPRI0 On (green) The CPRI link is functional.

On (red) The interface module fails to receive signals.


seconds (red)

The CPRI link has a loss-of-lock error.

CPRI1 On (green) The CPRI link is functional.

On (red) The interface module fails to receive signals.


seconds (red)

The CPRI link has a loss-of-lock error.


DCDU Module

The direction current distribution unit (DCDU) provides -48V DC

power of 10 outputs.

The functions of the DCDU are:

Receiving -48 V DC power input.

Distributing the -48 V DC power of 10 outputs for boards and modules in

the cabinet.

Providing surge protection of 10 kA in differential mode and 15 kA in

common mode and providing dry contact for surge protection failure.


DCDU Module

Panel of the DCDU (10 outputs)

Name Label Description

Power

input

terminal

NEG(-) DCDU low level input terminal

RTN(+) DCDU high level input terminal

Power

output port

SPARE2, SPARE1, BBU,

FAN, and RFU5-RFU0

Power ports supplying the 10 outputs of power

to the BBU, MRFUd, and fan box

Power

switch

SPARE2, SPARE1, BBU,

FAN, and RFU5-RFU0

Power switch controlling the 10 outputs for the

BBU, MRFUd, and fan box

Alarm

output port

SPD ALM Dry contact alarm output port


Fan Module The fan module performs the heat dissipation for the cabinet. One

fan module is installed with two fans.

The fan module performs the following functions:

Providing forced ventilation and dissipation for the cabinet

Reporting the temperature and rotation speed of the fans to the fan monitoring

board.

Interface

There is one interface on the panel. It is used to connect FMUA-FAN monitor

signal cable. The information of FAN temperature and speed will be sent to

FUMA with this interface. It also provide the power to FAN .


FMUA Board The FMUA (Fan Environment Monitor) is a fan environment monitoring

unit.

The FMUA performs the following functions: Leading -48 V DC power supply to the cabinet and supplying -48 V DC power supply

for the fan module.

Collecting environment alarm information in the cabinet. The environment alarm is

classified into temperature alarm, humidity alarm, smoke alarm, water immersion alarm,

and door status alarm.

Collecting surge protection alarm information of the DC power distribution unit.

Monitoring the operating status of fans. Supporting two modes of adjusting the rotation

speed of the fans: adjustment based on the temperature and adjustment controlled by

the main control unit.

Controlling the fan rotation. Stopping the rotation of the fans when the ambient

temperature is low.

Supporting the detection and reporting of the temperature.

Supporting the cascading and extension of RS485 ports. FMUAs can be cascaded.


FMUA Board LED on the board

LED Color Description Status Description

RUN Green Indicates the

running status of

the board

Blinking once every

two seconds

The board is running normally and the

communication with the BBU is normal.

Blinking four times

per second

There is power supply but the

communication with the BBU is

abnormal.

Off No power input is available.

ALA

RM

Red Indicates

whether there

are alarms

Blinking four times

per second

There are alarms from both the fans on

the left and right half subracks.

Blinking once every

two seconds

There is an alarm from the fan on the

right half subrack.

On There is a alarm from the fan on the left

half subrack

Blinking once every

four seconds

Other alarms

Off No power input is detected.


FMUA Board Ports on the panel

Type Ports Connector Description

Power port -48 V 7W2 power connector 48 V DC power input

RS485 port COM IN RJ45 connector Used in connection to the BBU or the

monitoring port on the upper-level FMUA

COM OUT RJ45 connector Used in connection to the lower-level FMUA

TEM RJ45 connector Cabinet temperature monitoring port

TEM_HUM

ARRESTER

RJ45 connector Used in connection to the surge protection

failure alarm port of the power distribution

unit

Fan port FAN0 4-pin connector Used in connection to the fan module on the

left half subrack FAN1

FAN2 4-pin connector Used in connection to the fan module on the

right half subrack FAN3

Boolean

port

The first group

(from left to right)

Dry contact connectors Extended Boolean ports

The second group Dry contact connectors

The third group Dry contact connectors Smoke sensor port, door status sensor port

The fourth group Dry contact connectors Water sensor ports


Batteries in the RF Cabinet

The batteries in the 3RFU cabinet serve as the power backup for the

BTS.

The -12 V 50 Ah battery or -12 V 92 Ah battery is allowed in the 3RFU

cabinet. The battery combination is as follows:

When the -12 V 50 Ah battery is used, four batteries in serial connection can

be configured to serve as the power backup of -48 V 50 Ah.

When the -12 V 92 Ah battery is used, four batteries in serial connection can

be configured to serve as the power backup of -48 V 92 Ah.

(1) -12 V 50 Ah battery (2) -12 V 92 Ah battery


Door Status Sensor in the RF Cabinet

The door status sensor detects the opening and closing of the cabinet door.




Chapter 3 BTS3900A network Topology


BTS3900A Topology BTS Topology

The topologies of the BTS are classified into star, chain, tree, and ring topologies.

E1/T1 cable can be used between BBU and BSC or transmission equipment,

Optical and LAN cable can be used between BBU and route equipment.

DRFU Topology

The BBU and MRFUd support multiple network topologies such as star, chain, and

ring topologies.

Only optical fiber can be used between MRFUd and BBU.


BTS Topology

The topologies of the BTS are classified into star, chain, tree, and ring

topologies.

Star mode Tree mode

Chain mode Ring mode


Summary

BTS3900A Function and Features

BTS3900A Hardware Structuresuch as BBU and MRFUd etc.

BTS3900A Network Topology

Thank You

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