Download - Huawei Bts3900 Hardware Structure Issue1.0

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HUAWEI BTS3900 Hardware Structure


Foreword

The BTS3900 developed by Huawei is an indoor macro BTS. The BTS3900 mainly consists of the BBU and DRFUs. Compared with traditional BTSs, the BTS3900 features simpler structure and higher integration.

In this slide, we’ll mainly introduce the hardware system structure, application scenarios, basic functions of modules, networking mode and typical configuration of the BTS3900


References

《 BTS3900 System Description 》《 BTS3900 Hardware Description 》


Objectives

Upon completion of this course, you will be able to:

Know the application scenarios of BTS3900

Grasp the hardware structure of BTS3900

Grasp the functions of the modules

Master typical configuration of BTS3900

Know the networking topology of BTS3900


Contents1. BTS3900 Overview

2. BTS3900 Hardware Components 2.1 BTS3900 basic structure

2.2 BBU hardware structure

2.3 Power supply system of BTS3900

2.4 Other boards and modules

2.5 Cables connection of the cabinet

3. Configurations of the BTS3900 3.1 Key parameters in BTS3900 configuration

3.2 Typical configuration

3.3 RF cable connection configuration

3.4 Topology configuration

3.5 Configuration principles


Contents

1. BTS3900 Overview

2. BTS3900 Hardware Components

3. Configurations of the BTS3900


Location of BTS3900

PSTN ISDN

PSPDN

Um Interface

BTS3900

BTS3900

BTS3900

BTS

OMC

HLR/AUC/EIR

BSC

MSC/VLR

SMC/VM

A Interface

MAPMAP

TUP,ISUPMS

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


Some Functions and Features It adopts the unified BTS platform developed by Huawei Wireless and

enables the smooth evolution from 2G to 3G. It supports the Abis IP/FE interface in hardware and enables Abis over

IP through software upgrade if required. It shares the BBU, which is the central processing unit, with the DBS39

00 to minimize the number of spare parts and reduce the cost. It can be flexibly installed in a small footprint and easily maintained w

ith low cost. It supports transmit diversity and PBT. It supports 2-antenna and 4-antenna receive diversity to improve the

uplink coverage. It supports the GPRS and EGPRS.


Some Functions and Features It supports the hierarchical cell, concentric cell, and micro cell. It supports multiple network topologies, such as star, tree, chain, r

ing, and hybrid topologies. It supports the A5/3, A5/2, and A5/1 encryption and decryption alg

orithms. It supports coexistence with the BTS3012. A single cabinet supports up to 12 carriers in the maximum cell co

nfiguration of S4/4/4. Multiple cabinets support up to 72 carriers in the maximum cell co

nfiguration of S24/24/24. Receiver sensitivity on TCH/FS is -113 dBm


Contents

1. BTS3900 Overview


3. Configuration of the BTS3900


Contents


2.1 BTS3900 basic structure






Structure of the BTS3900 Cabinet

-48V Cabinet-48V Cabinet

(1) Double radio filter unit(2) Fan box(3) GSM antenna and TMA control module(4) Baseband unit(5) Direct current distribution unit


Structure of the BTS3900 Cabinet

+24V or +220V Cabinet +24V or +220V Cabinet

(1) Double radio filter unit(2) Fan box(3) Baseband unit(4) Direct current distribution unit(5) Cable in/out unit (6) Power supply unit


Board/ module

Full Name Quantity

FullConfiguration

MinimumConfiguration

BSBC Universal BBU Subrack Backplane type C (2U) 1 1

UEIU Universal Environment Interface Unit 1 0

GTMU GSM Transmission and 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 1 1

GATM GSM Antenna and TMA Control Module 1 0

DPMU Power and Environment Monitoring Unit 1 0

PSU(AC/DC) Power Supply Unit (AC/DC) 3 0

PSU(DC/DC) Power Supply Unit (DC/DC) 4 0

Fan box Fan box 1 1

Abbreviations


Logical Structure and Signal Flow


Stack Mode

When two BTS3900 cabinets (-48

V) are stacked, the BBU is

installed only in the lower cabinet

and serves as the baseband

control unit for the two cabinets.


Stack Mode

When the BTS3900 cabinet (-48 V) is stacked on the BTS3900 cabinet (220 V or +24V), a maximum of nine DRFUs can be configured.

When two cabinets are stacked, the BBU is installed only in the lower cabinet and serves as the baseband control unit for the two cabinets.


Contents








BBU The typical power consumption of BBU is 35W

The weight of the BBU is 12 kg at most.

All the boards can be inserted from the front panel

The Permissible range of power input is –38.4 V DC to –57 V DC


Working Principles of the BBU


Boards and Modules in BBU

BSBC: The universal BBU subrack backplane type C GTMU: The GSM Transmission, Timing and Management Unit UBFA: The universal BBU fan unit type A UPEU: The universal power and environment interface unit UELP: The universal E1/T1 lightning protection unit UEIU: The universal environment interface unit


BSBC Board The BSBA provides slot 6 for the GTMU, slot 7 for a main control

board that supports 3G, and slots 0 to 5 as common slots. The GTMU is 1 U high. Therefore, from the view of the front panel, the GTMU is located in slots 5 and 6.

Provide backplane interfaces, communication channels, distribute clock signal and +12V power supply for the other boards


GTMU Controls, maintains, and operates the BTS

Supports fault management, configuration management, performance management, and security management

Monitors the fan module and the power supply module

Distributes and manages BTS clock signals

Provides clock input for testing

Provides the Ethernet port for terminal maintenance

Supports four E1 inputs

Provides the CPRI ports for communication with the DRFU


GTMU Ports

Port Type Corresponding cable Description

CPRI0 ～CPRI5

DLC Optical fiber between BBU and DRFU

Connected to DRFU for the optical signal transmission

ETH RJ45 Special Ethernet cable Terminal maintenance and commissioning

FE0 RJ45 Ethernet cable A reserved port that performs the

following function: Connects the BBU to

a routing device in the equipment room

through the Ethernet cable for

transmission

FE1 DLC Optical fiber

USB USB - A reserved port that performs the

following function: Automatically

upgrades the software through the USB

disk

TEST USB - Tests the output clock signals with a tester

E1/T1 DB26 male

BBU E1/T1 Provides the input and output of the four E1/T1 signals between the GTMU and the UELP or between the GTMU and the BSC


GTMU Indicators

Indicator

Color Status Description

RUN Green On Board has fault

Green Off Not power input or the board is faulty

Green Slow flash(1s on， 1s off) The board is operational.

Green Slow flash (2s on， 2s off) OML is abnormal

Green Fast flash (0.125s on, 0.125s off)

Board is loading software

ALM Red On A fault occurs in the running board.

Off No fault

ACT Green On The board is operational.

Off Board has fault

LIU0~LIU3

Green On E1/T1 local alarm

Fast flash (0.125s on, 0.125s off)

E1/T1 remote alarm

Off Not used or alarm has disappeared

CPRI0~CPRI5

Green On CPRI link is functional

Red On CPRI link is abnormal


GTMU Toggle Switch

Toggle switch

StatusDescription1 2

SW1 ON ON The E1 impedance is set to 75 Ω.

OFF ON The E1 impedance is set to 120 Ω.

ON OFF The T1 impedance is set to 100 Ω.

Toggle switch

Status

Description1 2 3 4

SW2 ON ON ON ON The E1 cable is grounded.

OFF OFF OFF OFF The E1 cable is not grounded.


GTMU toggle switch

Toggle switch

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.

Toggle

switch

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.


UBFA The universal BBU fan unit type A (2U) (UBFA) works with the air inlet box

of the cabinet to form a ventilation circuit, thus cooling the entire cabinet.

The UBFA module communicates with the GTMU to regulate the

temperature, adjust the fan speed, and report alarms. The UBFA module is

hot swappable. Indica

torColor Status Description

STATE Green Fast flash(0.25s on ， 0.25s off)

Can not communicate with the board and there is no alarm generated

Red On There is alarm

Green Slow flash(1s on， 1s off)

Runs normally


UPEU The universal power and environment interface unit type A (–48

V) (UPEU) supports the –48 V DC power input, supplies power to

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

multiple environment monitoring signals. Port Type Description

MON0

RJ45 Provides the input and output of the externally collected environment monitoring signals to the GTMU according to the RS485 communications protocol

MON1

RJ45 Reserved

EXT-ALM0

RJ45 Transmits the externally collected environment monitoring signals to the GTMU through communications protocol related to the dry contact

EXT-ALM1

RJ45 Reserved

PWR 3V3 -48V DC input


UEIU UEIU is the environment interface board of BBU ， it can support

multi-route monitoring signal input UEIU is optional and is only used when more ports are needed

Port Type Description

MON0

RJ45 Provides the input and output of the externally collected environment monitoring signals to the GTMU according to the RS485 communications protocol

MON1

RJ45 Reserved

EXT-ALM0

RJ45 Transmits the externally collected environment monitoring signals to the GTMU through communications protocol related to the dry contact

EXT-ALM1

RJ45 Reserved


UELP UELP is the E1/T1 signal lightening protection unit of BBU

and it can provide protection for 4 route E1/T1 signal

Port Type Relative cables

Description

INSIDE DB25 male

E1 transferring cable

Transfers the four E1/T1 signals between the UELP and the GTMU

OUTSIDE DB26 male

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


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DCDU Panel

a: Power switch b: Power output ports


Main Functions of DCDU 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


Ports and Switches of DCDU

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, DRFU, GATM, and fan box

Power switch SPARE2, SPARE1, BBU, FAN, and RFU5-RFU0

Power switch controlling the 10 outputs for the BBU, DRFU, GATM, and fan box

Alarm output port SPD ALM Dry contact alarm output port


DPMU and PSU The wiring unit is connected to the external power supply through

the terminals for L and N wires, and leads the power to the PSU

through the backplane.

The PSU converts the input power into the -48 V DC power.

The DPMU monitors the operating status of the PSU.

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

LOAD2(-), and RTN(+).

1) DPMU2) PSU 3) Wiring unit


Main Functions of PSU There are 2 kinds of Power Supply Unit (PSU), AC/DC and DC/DC. AC/

DC PSU converts 220V to -48V; DC/DC PSU converts +24V to -48V The AC/DC and DC/DC PSU monitor 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


LEDs of PSU

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.


Main Functions of PMU The power and environment monitoring unit (DPMU)

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


Ports of PMU

1. LEDs2. Power supply test ports 3. RS232/RS422 ports 4. Battery control switch 5. COM port

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 multimeter.

COM port Used in connection to the external signal transfer board

Backplane port Used in connection to the backplane


Power Distribution Mode 1 The BTS3900 cabinet can use three types of power inputs, namely, -

48 V DC, +24 V DC, and 220 V AC.

If the external -48 V DC power input is used, no additional power

system is required. The external -48 V DC power input is directly

connected to the power input terminals on the DCDU (10 outputs).

Then, the DCDU distributes the -48 V DC power to each module in

the cabinet.


Power Distribution Mode 2 When the external +24 V DC power or +220V AC power is used, PSUs an

d a cable in/out unit are configured in the cabinet. The PSUs convert the external power into the -48 V DC power and supply the -48 V DC power to the DCDU Then, the DCDU distributes the -48 V DC power to each module in the cabinet.


Power Distribution Mode 3 This is the power distribution when a -48 V DC cabinet is stacked on a

+24 V DC cabinet or +220V AC cabinet. The PSUs convert the external +24 V DC or +220VAC power into the -48 V DC power and supply -48 V DC power to the DCDUs in both cabinets. Then, the DCDUs distribute the -48 V DC power to the modules in both cabinets.


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Main Functions of GATM The GSM antenna and TMA control module (GATM) is a module

that controls the antenna and TMA. The GATM is optional.

Controls the RET antenna

Feeds power to the TMA

Reports the RET control alarm signals

Monitors the current from the feeder


Ports on the GATM Ports Connector Function

ANT0 SMA female Providing power for the RET antenna and transmitting control signals for the RET antenna

ANT1 SMA female Providing power for the antenna





COM1 RJ45 Used in connection to the BBU

COM2 RJ45 Providing the extended RS485 port to be cascaded with other devices

-48 V 7W2 Receiving the -48 V power input


LEDs on the GATM LED Color Description Status Meaning

RUN Green Indicator of the board running status

Blinking once every four seconds

There is power supply but the communication with the BBU is abnormal.

Blinking once every two seconds

The board is running normally and the communication with the BBU is normal.

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

ACT Green Indicator of the service running status

On The AISG link is normal.

Off The AISG link is abnormal.

Blinking frequently and irregularly

The AISG link is transmitting data.

ALM Red Alarm indicator

On An alarm is generated, such as an overcurrent alarm.

Off The module runs normally.


Features and Functions of Fan Box Provides forced ventilation and dissipation for the cabinet

Supports two modes of adjusting the rotation speed of the fans: adjustment based on the temperature and adjustment controlled by BBU

Detects the temperature

Communicates with BBU unit to report alarms and the adjusted rotation speed of the fans to BBU

Stops the rotation of the fans when the ambient temperature is low

A fan box is configured with one NFCB and four fans. The fans are configured in N+1 mode. When one fan fails, the other fans rotate at full speed.


Connectors and LEDs of Fan Box

Type Silk-Screen Connector Description

Power port -48 V 7W2 Used to introduce the -48 V DC power

Temperature sensor port

SENSOR RJ45 Used in connection to the external temperature sensor

Communication port

COM OUT RJ45 Used in connection to the lower-level cascaded fan box

COM IN RJ45 Used in communication with the central processing unit

LED Color Status Description

RUN Green Blinking four times per second

The communication with the central processing unit is not established but the module runs normally.


The communication with the central processing unit is established and the module runs normally.

Off There is no power input and the module is faulty.

ALM Red Blinking once every two seconds

An alarm is generated.

Off No alarm is generated.


Main Functions of DRFU One double radio filter unit (DRFU) provides two TRXs

The DRFU performs modulation and demodulation between

baseband signals and RF signals, processes data, and combines

and divides signals.


Working Principles of the DRFU

The DRFU consists of the high-speed interface unit,

signal processing unit, power amplifier, and dual-

duplexer.


DRFU Internal Structure 2 TRXs and 2 duplexers are integrated in DRFU module which can be connect

ed to antenna directly The RX_IN/OUT port of DRFU can support the receiving signal interconnecti

on between 2 DRFUs, so that it can support the diversity receiving between 2DRFUs

Interface Processing U

nit

DUP

DUP

CPRI-E

CPRI-W

ANTA

ANTB

RX-IN

RX_OUT


Ports of the DRFU Type Connector Ports Description

Port for transmitting and receiving RF signals

N female connector

ANT1 Used in connection to the antenna subsystem

ANT2

CPRI port SFP female connector

CPRI0 Used in connection to the BBU, or in connection to the upper-level cascaded DRFU

CPRI1 Used in connection to the lower-level cascaded DRFU

Port for transmitting RF signals between DRFUs

QMA female connector

RX1 in Input port for diversity signals in antenna channel 1

RX1 out Output port of diversity signals in antenna channel 1

RX2 in Input port for diversity signals in antenna channel 2

RX2 out Output port of diversity signals in antenna channel 2

Power port 7W2 power connector

PWR Receives power input


LEDs of the DRFU 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.


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.


The DRFU is being tested on the Site Maintenance Terminal.


LEDs of the DRFU VSWR Off (red) No VSWR alarm is detected.

Blinking once every two 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.


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.


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


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Cable Connection of -48V Cabinet

Cable Number

Cable Name Quantity

R1-R12 RF Jumpers 12

P1-P2 External Power Cables (-48 V) 2

P3-P8 Power Cables Between the DCDU and DRFUs 6

P9 Power Cable Between the DCDU and Fan Box 1

P10 Power Cable Between the DCDU and BBU 1

P11-P12 Reserved 2

S1-S6 CPRI Signal Cables Between the BBU and DRFU

6

S7 E1 Transfer Cable of the BBU 1

S8 Monitoring Signal Cables for the DCDU 1

S9 Monitoring Signal Cable for the Fan Box 1

S10 E1/T1 Cable of the BBU 1


Cable Connection of +24V Cabinet

Cable Name


P1–P2 Power Cables Between the PSU (DC/DC) and DCDU

2

P3-P8 Power Cables Between the DCDU and DRFUs 6

P9 Power Cable Between the DCDU and Fan Box 1

P10 Power Cable Between the DCDU and the BBU 1

P11-P12 Reserved 2

P13-P14 External Power Cables (+24 V) 4

S1-S6 CPRI Signal Cables Between the BBU and DRFU

6



S9 In-Position Signal Cable for the PSU (DC/DC) 1



Cable number

Quantity


Cable Connection of +220V CabinetCable

NumberCable Name Qua

ntity


P1–P2 Power Cables Between the PSU (AC/DC) and the DCDU

2

P3-P8 Power Cables Between the DCDU and the DRFUs 6

P9 Power Cable Between the DCDU and the Fan Box 1

P10 Power Cable Between the DCDU and the BBU 1

P11-P12 Reserved 2

P13-P14 External Power Cables (220 V) 2

S1-S6 CPRI Signal Cables Between the BBU and DRFU 6


S8 Monitoring Signal Cable for the DPMU 1





Contents

1. BTS3900 Overview




Contents


3.1 Key parameters in BTS3900 configuration






Antenna Modes Single antenna

The DRFU module has 1 working feeder so there is no receive diversity or transmit diversity

Single antenna, double receivers The DRFU module has 1 working TX/RX feeder and 2 way receive

diversity, one of the receiver is from the another DRFU

Double antennas The DRFU module has 2 working TX/RX feeders and 2 way receive

diversity

Double antennas, 4 receivers The DRFU has 2 working TX/RX feeders and 4 way receive diversity


DRFU Output Power in the BTS3900

Operating Frequency Band

Work Mode Output Power (GMSK/8PSK)

900 MHz Non-combination 45 W/30 W

900 MHz Combination 20 W/14 W

900 MHz PBT 71 W/47 W

1800 MHz Non-combination 40 W/26 W

1800 MHz Combination 18 W/12 W

1800 MHz PBT 63 W/42 W


DRFU Transmit Mode and Receive Mode DRFU transmit mode

Transmit independency or combining

PBT

Dynamic PBT

Transmit diversity

DRFU receive mode

Two way receive diversity

Four way receive diversity


Transmit Independency or Combining In transmit independency or combining mode, the system

decides which mode will work actually

In independency mode, TRX 0 occupies channel A while TRX1

occupies channel B

Interface P

rocessing Unit

DUP

DUP

CPRI-E

CPRI-W

ANTA

ANTB


Transmit Independency or Combining

Interface Processing

Unit DUP

DUP

CPRI-E

CPRI-W

ANTA

ANTB

In transmit independency or combining mode, the system decides which mode will work actually In transmit combining mode ，the two TRXs will be combined and transmitted through channel A


PBT In PBT mode, only the first TRX can work PBT mode can improve the transmitting power In PBT mode ， only channel A is used by downlink signal

Interface P

rocessing Unit

DUP

DUP

CPRI-E

CPRI-W

ANTA

ANTB


Dynamic PBT Dynamic PBT is a mode based on the operation of timeslots,

compared with static PBT, it brings the balance between capacity and coverage and does not cause the 50% decrease of capacity.

The subscriber occupies a TS under the detection of measure report. When the quality is lower than a threshold, the same No. of TS of the adjacent TRX will be used as the secondary TS by the subscriber to start PBT. (The former subscriber in the secondary TS will handover) When the quality is higher than a threshold, the PBT will be canceled and the secondary TS will be released.


Dynamic PBT

TimeslotsTimeslots TRXsTRXs

Good qualityGood quality

Poor qualityPoor quality

Signal qualitySignal quality

No signalNo signal


Transmit Diversity

In this mode, only the first TRX can work Transmit diversity mode improves the quality of downlink signal In this mode ， the signal from the first TRX is divided to 2 channels a

nd be transmitted through channel A and channel B

Interface P

rocessing Unit

DUP

DUP

CPRI-E

CPRI-W

ANTA

ANTB


Two Way Receive Diversity In this mode ， both of the 2 TRXs can work Each TRX receives the signal from 2 feeders In the following figure ， the TRX gets the receiving signal from channel

A and B of the single DRFU It is also possible for TRX to use the channel A receiver of another DRFU

Interface P

rocessing U

nit DUP

DUP

CPRI-E

CPRI-W

ANTA

ANTB

RX-IN

RX_OUT

From RX-in, TRX can also use the channel A of the other DRFU, so channel B of the two DRFUs are canceled


Four Way Receive Diversity In this mode, only the first TRX can work The working TRX gets the uplink signal from 4 feeders of 2 DRF

Us

Interface P

rocessing

DUP

CPRI-E

CPRI-W

ANTA

ANTB

RX-IN

RX_OUT

Interface P

rocessing

DUP

CPRI-E

CPRI-W

ANTA

ANTB

RX-IN

RX_OUT

2 channels from the

other DRFU


Contents








Typical Configuration 1


Contents








RF Cable Connection 1 One DRFU module

One dual-polarized antenna

Cell Type Supported

TRX Mode Antenna Mode

S1 (without transmit diversity)


Double Antenna

S1 (with transmit diversity)

Transmit Diversity

Double Antenna



Double Antenna


RF Cable Connection 2 (1) Two DRFU modules


Cell Type Supported


S2 (PBT) PBT Single Antenna

Double Receiver



Single Antenna

Double Receiver



Single Antenna

Double Receiver


RF Cable Connection 2 (2) Two DRFU modules


Cell Type Supported


S2 (with transmit diversity)

Transmit Diversity

Single Antenna

Double Receiver

S2 (4-way receive diversity)

4-Way Receive Diversity

Single Antenna

Double Receiver

S4 (transmit independency)


Single Antenna

Double Receiver


RF Cable Connection 3 Three DRFU modules

Two dual-polarized antennas

Cell Type Supported



DRFU0: Single Antenna

Double Receiver


Double Receiver

DRFU2: Double Antenna



Double Receiver


Double Receiver

DRFU2: Double Antenna




RF Cable Connection 4

Cell Type Supported

TRX Mode

Antenna Mode


Single Antenna Double

Receiver


Single Antenna Double

Receiver



Four DRFU modules

Two dual-polarized antennas


Contents








BTS3900 Topologies - Star The star topology applies to common

areas, especially densely populated areas, such as cities.

Advantages In the star topology, each site is directly

connected to the BSC. It has the following features:

Easy networking

Easy project implementation

Easy network maintenance

Easy network expansion

High network reliability

Disadvantages Compared with other topologies, the star

topology requires more transmission cables.


BTS3900 Topologies - Chain The chain topology applies to sparsely populated areas in strip-like terra

in, such as areas along highways and railway tracks. Advantages

The chain topology reduces cost in transmission equipment, construction, and transmission link lease.

Disadvantages As signals pass through many nodes, the transmission reliability in the chain topolo

gy is reduced. The faults in the upper-level BTSs may affect the lower-level BTSs. The number of levels in a chain network should not exceed five.


BTS3900 Topologies - Tree The tree topology applies to areas where network

structures, site distribution, and subscriber distribution are complicated, for example, an area where large-scale coverage overlaps hot spot or small-scale coverage.

Advantages The tree topology requires fewer transmission ca

bles compared with the star topology. Disadvantages

As signals pass through many nodes, the transmission reliability is reduced. This makes it difficult for maintenance and engineering.

The faults in the upper-level BTSs may affect the lower-level BTSs.

Capacity expansion is difficult. The number of levels in the tree should not excee

d five.


BTS3900 Topologies - Ring The ring topology applies to common scenarios. Due to its strong self-healin

g capability, the ring topology is preferred if permitted by the routing. Advantages

If there is a breaking point in the ring, the ring breaks into two chains at the breaking point automatically. In this way, the BTSs preceding and following the breaking point can work normally despite the breaking point; thus improving the robustness of the system.

Disadvantages In the ring topology, there is always a link section that does not transfer data.


DRFU Topologies Configuration

The DRFU supports

various network

topologies: star, chain,

and ring.


Contents








Basic Configuration Principles A single BTS3900/BTS3900A cabinet provides up to 12 carriers with th

e maximum cell configuration of S4/4/4, and supports the dual-band application.

Minimum cost Smooth upgrade of configuration Antenna configuration principles Minimum number of DRFUs Minimum number of BBUs Highest reliability Mode of configuring two TRXs in one sector


RF Configuration Principles A maximum of three levels of DRFUs can be connected to one BBU. For S4/4/4 cell configuration and lower configurations, the star topology is recom

mended between the BBU and the DRFU; for the configuration higher than the S4/4/4 cell configuration, the ring topology is recommended between the BBU and the DRFU.

Minimum number of antennas. Each sector of the BTS must be configured with the minimum number of antennas. For the 2-antenna receive diversity, each sector has two antenna channels; for the 4-antenna receive diversity, each sector has four antenna channels.

Non-combination in the transmit channel. The non-combination configuration is recommended for the DRFU to avoid the power loss in combination and to reduce the power consumption of the BTS. If combination is required, the cavity combiner must be configured outside the DRFU and one combination is recommended.


Configuration Principles of the BBU Minimum number of trunk cables. You can determine the numbe

r of trunk cables as required, and take the existing configuration for saving transmission resources into account in networking.

Minimum number of UPEUs. The configuration of a single UPEU is recommended. The redundancy backup mode can be configured if required.

One BBU supports six CPRI ports. The star topology is recommended between DRFUs.


Summary

BTS3900 functions and features

BTS3900 hardware structure and components

Working mode, typical configurations, RF cable

configurations, topology configurations,

configuration principles

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