bts3012a auxiliary system

7/27/2019 BTS3012A Auxiliary System

1/23

Technical Manual Auxiliary SystemM900/M1800 BTS3012A Base Transceiver Station Table of Contents

Huawei Technologies Proprietary

i

Table of Contents

Chapter 1 Introduction to Auxiliary System ...............................................................................1-11.1 Overview............................................................................................................................ 1-11.2 Introduction to Auxiliary System ........................................................................................ 1-1

Chapter 2 Power Supply System................................................................................................. 2-12.1 AC/DC Distribution Unit ..................................................................................................... 2-1

2.1.1 Overview ................................................................................................................. 2-12.1.2 AC Power Distribution Principle .............................................................................. 2-12.1.3 DC Power Distribution Principle.............................................................................. 2-4

2.2 TSU.................................................................................................................................... 2-62.3 Storage Batteries............................................................................................................... 2-7

2.3.1 Built-in Storage Battery Box.................................................................................... 2-72.3.2 Extended Storage Battery Cabinet.......................................................................... 2-7

Chapter 3 Environment Monitoring System ...............................................................................3-13.1 Overview............................................................................................................................ 3-13.2 TCU.................................................................................................................................... 3-2

3.2.1 Overview ................................................................................................................. 3-23.2.2 Architecture and Principle ....................................................................................... 3-3

3.3 EMUA................................................................................................................................. 3-43.3.1 Performance Index.................................................................................................. 3-43.3.2 Functions................................................................................................................. 3-5

Chapter 4 Temperature Adjustment System ..............................................................................4-14.1 Overview............................................................................................................................ 4-14.2 Air Conditioner ................................................................................................................... 4-14.3 Heat Exchanger ................................................................................................................. 4-1

Chapter 5 Transmission Mode..................................................................................................... 5-15.1 E1 Transmission ................................................................................................................ 5-15.2 SDH Transmission............................................................................................................. 5-3

5.2.1 Ring Networking...................................................................................................... 5-35.2.2 Chain Networking.................................................................................................... 5-4


2/23

Technical Manual Auxiliary SystemM900/M1800 BTS3012A Base Transceiver Station Chapter 1 Introduction to Auxiliary System


1-1

Chapter 1 Introduction to Auxiliary System

1.1 Overview

The auxiliary system refers to the equipment and devices in various working systems

that assist the normal operation of BTS. To help introduce the auxiliary system in this

manual, all the functional boards in BTS3012A are referred to as the main equipment,

and the other devices in the BTS3012A are referred to as the auxiliary equipment.

The principles of the all the boards in BTS3012A are described in M900/M1800

BTS3X Series Base Transceiver Station Technical Manual - System Principle. Thecomponents of the BTS3012A auxiliary system include power distribution system,

environment monitoring system and temperature adjustment system, as illustrated in

Figure 1-1.

Figure 1-1 Components of BTS3012A auxiliary system

In addition, this manual also describes the transmission equipment principle and

lightning protection.

1.2 Introduction to Auxiliary System

I. Power Distribution System

The power distribution system supplies power for the stable working of BTS main and

auxiliary equipment.

The BTS3012A power distribution system consists of three parts:

z AC/DC power distribution unit


3/23

Technical Manual Auxiliary SystemM900/M1800 BTS3012A Base Transceiver Station Chapter 1 Introduction to Auxiliary System


1-2

z Transmission power supply Unit (TSU)

z Storage batteries

II. Environemtn Monitoring System

The environment monitoring system accomplishes the monitoring of the environment

variables in the cabinet and the alarm processing functions to keep the cabinet in a

suitable temperature and humidity range and ensure safe and reliable operations of

the equipment.

TCU, EMUA and sensors are the major components of the environment monitoring

system.

III. Temperature Adjustment System

The temperature adjustment system can adjust the internal temperature of the

cabinet to get the main equipment to work reliably in a mild environment. The air-

conditioner and the heat exchanger are the major component of temperature

adjustment system.

IV. BTS Transmission Equipment

Many types of small transmission equipment can be embedded in BTS3012A to

support various transmission modes, including:

z E1 (75 ohm/120 ohm)z SDH

z Microwave

V. BTS Lightning Protection Grounding

As an outdoor macrocell BTS, BTS3012A is required to have higher lightning

protection performance. Therefore, all ports where lightning might be led to, including

AC power port, E1 port and antenna and feeder ports, have been designed with

comprehensive lightning protection techniques.

Note:Some of the above auxiliary equipment are optional. If no special note is given in the

following chapters, the equipment mentioned is mandatory.


4/23

Technical Manual Auxiliary SystemM900/M1800 BTS3012A Base Transceiver Station Chapter 2 Power Supply System


2-1

Chapter 2 Power Supply System

The power supply system of BTS3012A consists of the AC/DC distribution unit,

transmission power supply unit (TSU), and storage batteries.

2.1 AC/DC Distribution Unit

2.1.1 Overview

Functionally, the AC/DC distribution unit accomplishes two functions:

z AC distribution

z DC distribution

The AC distribution unit is further divided into two parts:

z AC distribution part supplying power to the main equipment

z AC distribution part supplying power to the auxiliary equipment

Figure 2-1 shows the AC/DC power distribution principle of BTS3012A.

PSU

subrack

220 V ACpower input

220V AC

Auxiliary

equipment

+24V DC

DC power distribution

part for main

equipment+24V DC

Batteries

Auxiliary

devices

Main

equipment

AC powerdistribution

unit

DC power distribution

unit for auxiliary

equipment

Figure 2-1 Principle of AC/DC distribution unit

2.1.2 AC Power Distribution Principle

The AC power distribution unit of BTS3012A supports:

z 220 V AC three-phase power distribution

z 220 V AC single-phase power distribution

z 110 V dual-live power distribution

I. 220 V AC Three-Phase Power Distribution

The three-phase 220 V AC power travels through the lightning protecting module and

the EMI filter, and then is accessed to the AC power distribution unit. The power is


5/23



2-2

further distributed to the TCU, air conditioner or heat exchanger, PSU and the

standby socket. The input end of each phase is protected by a miniature circuit

breaker (MCB). Refer to Figure 2-2 for the AC power distribution principle.

EMIfilter

TCU

Air conditioner or

heat exchanger

Contactor

Socket

PSU

subrack

L3

L2

L1

N

Arrester

Gounding barPMU

TCU switch

ACU/HX switch

L3

L2

L1

N BTS switch

AUX switch

L

N

L

N

L

N

L

N

AC power distribution unit

DC power

distributionunit

220V AC

input

Figure 2-2 Principle of AC power distribution unit (220V AC three-phase distribution

mode)

II. 220V AC Single-Phase Power Distribution

When the 220V AC single-phase power distribution is adopted, the single-phase

power distribution mode is converted to three-phase power distribution mode throughthe power engineering interface box. The power distribution principle in the cabinet is

the same as that of the 220 V AC three-phase power distribution mode as shown in

Figure 2-3.

EMI

filter

TCU

Air conditioner or

heat exchanger

Contactor

Socket

PSUsubrack

L3

L2

L1

N

Arrester

Grounding barPMU

TCU switch

ACU/HX switch

L3

L2L1

N BTS switch

AUX swtich

L

N

L

N

LN

L

N

220V AC

input

M

C

B

L

N


DC power

distribution unit

Figure 2-3 Principle of AC power distribution unit (220V AC single-phase distribution

mode)


6/23



2-3

III. 110V AC Dual-Live Power Distribution

When the 110V AC dual-live power distribution is adopted, the power input adopts the

method of 2-channel L and 1-channel N.as shown in Figure 2-4.

173220VAC

L1

L2

L3

L1

L2

N

100127VAC

100127VAC200254VAC

Phase voltage 100127VACLine voltage 173220VAC

173220VAC

Three phase star

four wiredearthed neutral

Single phasethree wired

earthed neutral

Phase voltage

Line voltage

Figure 2-4 Power input mode of 110V AC dual-live cable power supply

The principle of power distribution inside cabinet is the same as that of 220 V AC

three-phase power distribution. The power input connection is different. Figure 2-5

shows the principle.

EMIfilter

TCU

Air conditioner or

heat exchanger

Contactor

Socket

PSU

subrack

L1

L2

Arrester

Grounding barPMU

TCUswitch

ACU/HXswitch

L3

L2

L1

N BTS switch

AUX switch

L

N

L

N

L

N

L

N


DC power

distribution unit

L3

L2

L1

N

N

Figure 2-5 Principle of AC power distribution unit (110V AC dual-live distribution

mode)


7/23



2-4

2.1.3 DC Power Distribution Principle

The DC power distribution unit of BTS3012A is responsible for the distribution of +24

V DC output from the PSU. The AC/DC conversion is accomplished by the PSU. SeeFigure 2-6 for the principle of AC/DC conversion. The 220 V AC is output from the AC

power distribution unit to the 220 V AC input busbar on the backplane of the public

resource frame. Then it is converted to multiple channels of +24V DC by the PSU

(AC/DC) module on the backplane and is output to the output busbar.

AC input lightning protection power distribution unit A1441Z

PSU PMUPSU PSU

220 V AC input

+24 V DC output

Input bus bar

Output bus bar

DC ditribution copper bar

Figure 2-6 Principe of AC/DC conversion

DC distribution copper bar allocates the +24 V current output from PSU to two units:

z Power distribution unit for auxiliary equipment

z Power distribution unit for main equipment

I. DC Power Distribution for Auxiliary Equipment

The DC power distribution for auxiliary equipment outputs 6 channels of DC to the

following devices:

z TSU

z Backup switches

z Fans for auxiliary equipment

z Lights

z Storage batteries

z Storage battery cabinet

See Figure 2-7 for the principle of DC power distribution for the auxiliary equipment.


8/23



2-5

TSU switch

SPARE switch

Heat exchanger

switch

Fan of auxiliary

equipment switch

LAMP switch

Contactor Fuse

Batterycabinet

Battery

cabin

+24V DC

DC power distribution unit

for auxiliary equipment

TSU

Backup switch

Heat

exchanger

Fan of auxiliary

equipment

Lamp

Figure 2-7 DC power distribution for auxiliary equipment

II. DC Power Distribution Principle for Main Equipment

The DC power distribution unit outputs 14 channels of DC to the following devices:

z TRXs

z

CDUsz TMUs

z The fan for the main equipment

See Figure 2-8 for the principle of DC power distribution for the main equipment.


9/23



2-6

DC power distribution unit

for main equipment

+24V DC

2TRX

2TRX

2TRX

2TRX

2TRX

2TRX

CDU

CDU

CDU

CDU

CDU

CDU

TMU

Fan of mainequipment

Figure 2-8 DC power distribution for main equipment

2.2 TSU

Note:The TSU is an optional device.

BTS3012A provides three types of power supply for its built-in transmissionequipment:

z +24 V DC

z 220 V AC

z -48 V DC

The transmission power supply unit (TSU) is a DC/AC converter that converts +24 V

DC output power from the PSU to -48 V DC power that can be used by the built-in

transmission equipment. The TSU works in the 1+1 backup mode. Normally, the two

TSUs output equalized current. When one TSU gets faulty, the other TSU supplies

power to the transmission equipment and reports alarms.


10/23



2-7

2.3 Storage Batteries

Note:Storage batteries are optional.

When the mains supply is cut off, BTS3012A can continue its services with the power

supply from storage batteries. The built-in storage battery box and extended storage

battery cabinet are provided for BTS3012A.

2.3.1 Built-in Storage Battery Box

The built-in storage battery box is installed in the auxiliary equipment and

accommodates two 100 Ah storage batteries. It can sustain the service of three

BCCH carriers for above 30 minutes when the mains supply is cut off.

The technical indices of a common storage battery are listed below:

z Rated voltage: 12 V DC

z Rated capacity: 100 Ah

z Working temperature:-15C to +45C

z Floating voltage: 13.38 V (+25C)

z

Maximum charging current: 25 A

2.3.2 Extended Storage Battery Cabinet

The extended storage battery cabinet has more powerful power backup capacity. It

can accommodate twenty four storage batteries with rated voltage as 2 V to improve

the power supply duration after the mains supply is cut off. Under full configuration of

the BTS3012A, the power backup duration is more than 4 hours.

Technical indices of the extended storage battery cabinet are listed below:

z Rated voltage: 24 V DCz Rated capacity: Optional (400 Ah, 650 Ah)

z Working temperature: -20C to +50C

z Floating voltage: 26.8 V (+25C)

z Maximum charging current: 130 A


11/23

Technical Manual Auxiliary SystemM900/M1800 BTS3012A Base Transceiver Station Chapter 3 Environment Monitoring System


3-1

Chapter 3 Environment Monitoring System

3.1 Overview

As the core control system of BTS3012A, the environment monitoring system is

responsible for monitoring and controlling the environment in BTS3012A. The system

consists of the following parts:

z Sensors

z Temperature control unit (TCU)

z PMU

z TMUz EMUAThe specific functions of these parts are described as follows:

1) Sensors are embedded in the BTS3012A cabinet and the extended storage

battery cabinet. Environment variables are collected by PMU.

z The BTS3012A cabinet contains the temperature sensor, door control sensor,

water sensor and smog sensor.

z The extended storage battery cabinet contains the temperature sensor and door

control sensor.

2) TCU provides temperature protection for the main equipment. When the

temperature is too high or too low, TCU will cut off the 220 V AC input power and

the +24V DC output power from the storage batteries and switch off some of the

boards to prevent damage to the main equipment.

3) TMU collects the Boolean values of the alarm input of the TSU, AC lightning

protection unit, regulator and the air-conditioner through the temperature control

backplane (TCB).

4) EMUA is used for monitoring environment parameters and voltage of BTS3012A,

and for real-time detecting relevant electric amperage or non-electric amperage

when equipped with a sensor. Its functions includes 32 channel extended

Boolean value detection, 4 extended analog input, 6 channel relay output, and

basic environment parameter monitoring.


12/23



3-2

Sensor

AC lightning

protection

board

TMU

PMU

EMUA

Air conditioner/

Heat exchanger

TRX/CDU

Battery

TCU

Controlsignal

Alarm

signal

Temperature

WaterSmoke

Access control

Monitoring

subsystem

Control

signal

Controlsignal

Figure 3-1 BTS3012A environment monitoring system

Note:The detailed function description of PMU and TMU is given in M900/M1800

BTS3012A Base Transceiver Station Technical Manual - System Principle, so they will

not be repeated here.

3.2 TCU

3.2.1 Overview

The temperature control unit (TCU) has two functions:

z Monitoring the temperature in the cabinet in real-time. By controlling the power

distribution of the cabinet, it prevents over-high or over-low temperature from

damaging the equipment and components. In this way, the normal working of the

main equipment can be assured.

z Driving the cabinet combining clock.


13/23



3-3

3.2.2 Architecture and Principle

I. Principle of Temperature Monitoring

TCU controls the 220 V AC input from the external power supply, the +24 V DC output

of the storage batteries (excluding the power distribution of the air-conditioner) and

the power-on/off commands for some boards according to the temperature of the

cabinet. For the control logic of TCU, refer to Figure 3-2.

TCU

TRX/CDU

Storage battery

220V AC

controlsignals

Figure 3-2 TCU control logic

TCU takes different measures to protect the main equipment at different temperature

control points. Look at the following example.

If the cabinet operates at the initial temperature of -20C, the main equipment works

in protection state. The air conditioner/heat exchanger will be working, but some non-

BCCH carrier power amplifier will be closed. Specific number of power amplifiers to

be closed can be configured through BSC data configuration. In this case, no power

supply will be input for the PSU.

If the temperature control device is started and the temperature goes higher until -5C,

the main equipment will exit the protection state, the PSU will be powered on and

some non-BCCH carrier power amplifiers that have been closed will be re-started.

When the temperature rises to +60C, the main equipment will enter protection state

again and the system power supply will be cut off, including PSU and storage

batteries.

Similarly, when the temperature goes down to +50C, the main equipment will re-exit

the protection state. When the temperature goes down to -15 C, the main equipment

will enter the protection state again.


14/23



3-4

II. Principle of Driving Cabinet Combining Clock

TCU performs the driving distribution of the cabinet combining clock and the match

setting of the control signal CBUS1. Figure 3-3 shows the principle of driving the

cabinet combining clock.

TMU 1 2 3 4 TRB

5 6

When TCU is installed in main

cabinet, here outputs the second

clock source.When TCU is installed in extension

cabinet, here receives the clock

from main cabinet.

When TCU is installed in maincabinet, here outputs the first clock

source.TCU

Figure 3-3 Principle of driving cabinet combining clock

Warning:

When the TCU powers off or is replaced, all other boards power off and the servicesare interrupted.

3.3 EMUA

3.3.1 Performance Index

I. Compatible with 24 V, 48 V, and 60 V power input

z For 24 V power input, the voltage range shall be 18 V30 V;

z For 48 V power input, the voltage range shall be 42 V60 V;

For 60 V power input, the voltage range shall be 48 V72 V


15/23



3-5

II. Supporting Active/Standby RS422 Serial Port and RS232 Serial Port for

Debugging Purpose

Primary serial port 1 is connected to BTS according to BTS O&M Low-speed Link

Protocol or CDMA EMU (Environment Monitoring Unit) Protocol. RS232 serial port

share a common physical interface with standby RS485 serial port.

3.3.2 Functions

Main functions of EMUA are listed as follows:

I. Mornitoring Basic Enviornment Parameters of BTS

EMUA can collect the following data:

z The temperature and moisture

z Watering

z Access control

z Intrusion

z Smoke

The collection items can be enabled or disabled by DIP switch.

You can also use the DIP switch to select alarm level for watering, intrusion, smoke,

and extended Boolean value.

The threshold value of the temperature alarm is - 20C + 80C. The threshold value

of the moisture alarm is 0% 99%.

Note:Temperature alarm, moisture alarm, and watering alarm are immediate alarms. Anti-

theft alarm and smoke alarm are retainable alarms, and such alarms can only recover

after you manually delete them. Ensure all the alarms can be shielded from the

hardware.

II. Detecting Voltage of Power Supply

Range of detection: 18 V 72 V. Accuracy: 1%.

You can set the threshold of voltage alarm from MPU of BTS. If the MPU does not

deliver the threshold of voltage alarm, you can judge it from the detected voltage in

following criterion:


16/23



3-6

z If the detected voltage is not less than 36 V, then the power supply is regarded

as 48 V power input. In this case, the upper threshold is 57 V, and the lower is

42 V (defaulted in 48 V system).

z

If the detected voltage is less than 36 V, the power supply is regarded as 24 Vpower input. In this case, the upper threshold is 28 V, and the lower is 20 V

(defaulted in 24 V system).

III. Automatic Resetting when Communication Is Broken

EMUA automatically resets 1 minute after the normal communication between host

and EMUA is broken. If EMUA does not communicate with the host after power-on,

such resetting will not occur.

IV. Checking 32 Extended Boolean Values

1) You can access 8-channel extended Boolean value to passive main contact point

signals or DC active signals by selecting hardware. The rest 24-channel

extended Boolean value can only be accessed to passive main contact point

signals

2) Collectors (sensors) for external passive main contact points can be mutually

isolated or connected through common end.

3) EMUA can decide the level is high or low.

z If the amplitude of DC active signal is 5 V26 V, then the signal is a high

level;,

z If the amplitude of DC active signal is 0 V1 V, then the signal is a high

level;

z If the amplitude of DC active signal is 1 V5 V, then the signal can be

decided to either high level or low level

4) The output level of Boolean value extended interface must be clearly defined and

have definite identification. The 16 mandatory Boolean values include eight 12 V

extended Boolean value input channels (Channel 0Channel 7) and eight 24 V

extended Boolean value input channels (Channel 8Channel 15). Among the

12 V channels and 24 V channels, there are respectively two accessible positive

signals..5) The 16 optional Boolean values include eight 12 V extended Boolean value input

channels (Channel 16Channel 23) and eight 24 V extended Boolean value

input channels (Channel 24Channel 31). The channel identification is printed on

the silk screens inside the chassis.

V. Configuring Lightning Protection Panel with 32-channel Boolean Value to

Protect Inputted Signals from Lightning

Nominal discharging current of lightning protection panel is 15 KA (8/20s surge

current). An Outdoor Boolean value signal shall pass the lightning protection panel


17/23



3-7

before it accesses EMUA. In this way, alarm box can avoid the port damage or

incorrect alarm caused by surge current of outdoor signal because the lightning

protection panel can endure 15KA 8/20s of surge current for 10 times. EMUA has

EAC lightning protection panel. The protection level can reach 15 KA for commonmode and differential mode, residual voltage 75 V for the line-line and line-ground.

VI. Four Extended Analog Collection Channel

The input analog quantity can be current signals at 4 mA20 mA or voltage signal at 0

V5 V.

VII. Six Relay Output

The output of relay is conducted through telecommunication commands. The contact

point capacity of relay is 1A/ 30V DC. Every relay provides constantly open and

constantly closed contact points.


18/23

Technical Manual Auxiliary SystemM900/M1800 BTS3012A Base Transceiver Station Chapter 4 Temperature Adjustment System


4-1

Chapter 4 Temperature Adjustment System

4.1 Overview

The heat dissipation and heating under low temperature of outdoor BTS3012A are

accomplished by the temperature adjustment system. The temperature adjustment

system has high reliability performance and reports alarms when faults occur. The

temperature adjustment of BTS3012A is accomplished by the air-conditioner or heat

exchanger.

4.2 Air Conditioner

BTS3012A is a complete outdoor BTS with enclosed cabinet architecture. When the

cabinet works at a high temperature, the internal temperature of the cabinet will go up

quickly so that the cabinet cannot work normally, because the large amount of heat

generated by the cabinet itself cannot be dissipated due to the enclosed architecture.

To reduce the internal temperature of the cabinet, the air-conditioner is installed in the

front door of the cabinet to dissipate heat. The air-conditioner will form a temperature

close loop to monitor and control the cabinet internal temperature. When the air-conditioner detects low temperature in the cabinet, it will start its internal heating

boards and the inner circling fans to provide heating to the cabinet. When high

temperature is detected, the air-conditioner will start cooling function to keep the

working temperature in the cabinet within normal working range. In this way, the

cabinet can work reliably in both high and low temperatures.

The technical specifications of the air-conditioner are listed below:

z Rated voltage: 220 V AC ! 10%

z Rated frequency: 50/60 Hz ! 3 Hz

z Heating power: 2600 W

z Refrigerating power: 1600 W


4.3 Heat Exchanger

The heat exchanger is the other option to control the internal temperature. It

incorporates a simple design with a dry contact closure each for high temperature

alarm and low temperature alarm. The heat exchanger sets up a closed loop and

provide heat dissipation capacity when the maximum internal temperature is greater


19/23

Technical Manual Auxiliary SystemM900/M1800 BTS3012A Base Transceiver Station Chapter 4 Temperature Adjustment System


4-2

than the maximum external temperature, Compared with air conditioners, heat

exchangers typically use fewer, higher reliability components, and have a less

complicated design, all at a lower cost.

The technical indices of the heat exchanger are listed in the following:

z Rated voltage: 220 V AC ! 10%

z Rated frequency: 50 Hz ! 3 Hz

z Heat exchanging power: 500 W

z Heating power: 2700 W



20/23

Technical Manual Auxiliary SystemM900/M1800 BTS3012A Base Transceiver Station Chapter 5 Transmission Mode


5-1

Chapter 5 Transmission Mode

BTS3012A supports multiple embedded transmission modes as described below:

z Reserving a space with standard 5U high and 19-inch wide for installing the

transmission device.

z Providing 1-channel 24 V power supply or 1-channel 220 V power supply

z Providing 4-channel 48 V power supply when equipped with TSU

z Reserving cable outlets for embedded microwave and SDH

This chapter describes the E1 transmission and SDH transmission networking modes

for BTS3012A.

5.1 E1 Transmission

The E1 networking of BTS3012A supports star, tree and chain networking modes

according to the actual deployment of a site.

I. Star Networking

Star networking applies to common deployment. Each site can be connected to its

BSC directly via E1 links. Therefore, star connection mode enjoys simple networking,easy and convenient maintenance, engineering and capacity expansion. In star

networking mode, signals travel through fewer parts and the line reliability is high.

However, it requires greatest amount of transmission links among all the networking

modes. Therefore, star networking is usually applied to densely populated cities.

Figure 5-1 shows the star connection of BTS3012A, where each single line

represents one channel of E1 link.

BSC

BTS3012A

BTS3012A

BTS3012A

Figure 5-1 E1 star networking of BTS3012A


21/23



5-2

II. Tree Networking

In tree mode, the networking is rather complicated. Signals travel through more parts

and the line reliability is low. This makes engineering and maintenance more complex.

Faults in the upper level site might affect normal operations in the lower level site. Re-

constructing the whole network might be done for capacity expansion. However, it

requires less transmission links than star networking. Therefore, tree networking is

usually applied to large areas with low population density.

Note that the levels of site signals traveling from BSC are limited. Usually, the series

connection of sites cannot exceed 5, or we can say, the depth of the tree cannot

exceed 5, because the BTS clock generally takes the phase lock of its upper network

and each phase lock will bring along the degradation of clock quality.

Figure 5-2 shows the tree networking of BTS3012A, where, each single linerepresents one channel of E1.

BSC BTS3012A

BTS3012A

BTS3012A

Figure 5-2 E1 tree networking of BTS3012A

III. Chain Networking

In chain networking mode, signals travel longer and the line reliability is poor.

Therefore, chain networking can be applied to strip-shaped areas with low population

density, such as the area along railways and subways. In such areas, chain

networking can better meet users' requirement and greatly reduce the amount of

transmission equipment required. Similar to tree networking, the number of node

series connected under chain networking cannot exceed 5.

Figure 5-3 shows the BTS3012A chain networking, where each single line representsone or multiple channels of E1.

BSC BTS3012A BTS3012A

Figure 5-3 E1 chain networking of BTS3012A


22/23



5-3

IV. Ring Networking

In ring networking mode, the reliability of the site is high. When a BTS on the front

part of the transmission chain is power off or faulty, this networking mode ensures the

following BTSs works normally.

In normal status, the BTSs forms a common chain connection in the sequence as

BTS1, BTS2, BTS3 (ring direction). If any one of the nodes is broken, the networking

mode of the BTSs before this node remains the same. The ones after this node form

a new chain in the reversing sequence (anti-ring direction).

The advantage of ring networking over chain networking is that when one BTS is

down, the other BTSs can keep working normally by splitting the chain into two new

chains. This increases the reliability of the system.

BTS1 BTS2 BTS3

BSC

A B C D

Figure 5-4 BTS E1 ring networking

5.2 SDH Transmission

If SDH transmission equipment is installed, BTS3012A can support SDH transmission.

When deciding the chain connection or ring connection for SDH networking, you have

to take into consideration the actual distribution of network routes. Usually, ring

connection is adopted, because it has high self-healing capability as long as there is

appropriate route distribution. While for the areas along railways and subways, chain

connection is usually adopted.

5.2.1 Ring Networking

Ring networking has high self-repairing capability. When an optical fiber gets

damaged, ring network can repair itself into a chain network, and the service will not

be affected. Figure 5-5 shows the ring connection for SDH networking, where each

single line represents one or multiple channels of E1 and each pair of lines represent

one pair of optical fibers.


23/23



5-4

BSC BTS3012A BTS3012AOpticaltransceiver

Figure 5-5 SDH ring networking of BTS3012A

5.2.2 Chain Networking

Figure 5-6 shows the SDH chain networking, where each single line represents one

channel of E1 and each pair of lines represent one pair of optical fibers.

BTS3012A BTS3012ABSCOptical

transceiver

Figure 5-6 SDH chain connection of BTS3012A

bts3012a auxiliary system

Documents

auxiliary steam system in thermal power plant.ppt

system study: auxiliary feedwater 1998 2018

schematic diagram:safety system annunciator auxiliary

auxiliary feedwater system automatic initiation and …

8. yazd-system description for auxiliary steam...

auxiliary programs - energyplus documentation · auxiliary...

auxiliary system planning

ssaa power station-boiler auxiliary cooling water system

a rfid landmark navigation auxiliary system

auxiliary/emergency feedwater system reliability, … ·...

31040851-bts3012a installation manual-antenna feeder install

generator auxiliary system

section- 4 auxiliary power supply system - guvnl

hydraulic system components auxiliary products

functional relations in the english auxiliary system

ome201102 gsm bts3012a hardware structure issue1.0

31040851-bts3012a installation manual-antenna feeder...

auxiliary unit accounting system manual

section- 4 auxiliary power supply system

canadian coast guard auxiliary - pacific safety management...