OMF000004 Radio Frequency Parts and Antenna-Training-20060531-A-2.0

8/12/2019 OMF000004 Radio Frequency Parts and Antenna-Training-20060531-A-2.0

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HUAWEI TECHNOLOGIES CO., LTD. All rights reserved

www.huawei.com

Internal

OMF 000004

Radio Frequency Part and

Antenna

ISSUE 2.0


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HUAWEI TECHNOLOGIES CO., LTD. All rights reserved Page 1

RF components are widely used in

wireless system, and effectperformance of network


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Upon completion this course, you will be able to:

Understand the structure and features of

combination unit

Master the key specifications of antenna

Be able to choose the suitable type of RF

component


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Chapter 1 RF Part in BTS

Chapter 2 Antenna

Chapter 3 Feeder and TTA


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RF Device of BTSAntenna

TTA

Antennastand

Jumper betweenantenna and TTA

Jumper betweenTTA and feeder

Feeder

Lightening

arrester

Jumper betweenlightening arresterand cabinet

BTS312

cabinet

SWITCH BOX

FAN BOX

AIR BOX

P

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TDU

FAN BOX

AIR BOX

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Introduction

RF device in BTS includes two parts

Indoor: combiner and splitter unit

For example: CDU module, SCU module and EDU module

Outdoor: antenna, feeder, TTA (tower top amplifier), jumper and

lightning arrester


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Function of Combiner and Divider

Use one antenna to support multiple TX/RX

signals, decreases the amount of antenna and

feeder

Complete duplexer of TX/RX and combine TX

signal filter, amplify and split the RX signal

Provide power for TTA


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CDU (Combining and Divider Unit)

Tx1

Tx2

Tx_Comb

Tx_Dup

combiner duplexer

divider

divider

amplifier

filter

Rx1Rx2

Rx3Rx4

Rx5

Rx6

Rx7

Rx8

HL_out

HL_in

RxD_out

RxD

Tx/Rx_ANT


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SCU (Simple Combiner Unit)

TX1

TX2

TX3

TX4

TX -Comb

combiner

combiner

combiner


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EDU (Enhance Duplexer Unit)

Tx1 duplexer

divider

amplifier

Rx1

Rx2

Tx/Rx_ANT1

divider

amplifier

Rx1

Rx2

duplexerTx/Rx_ANT2Tx2


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Comparison among Different Combining Units

combine

mode

typical lossvalue of

TX(dB)

pricecomparison

(per TRX)

CDU

combine twoTX signal

one step 3dBcombiner

4.5 middle

SCUcombine fourTX signaltwo step 3dB

combiner

6.8 low

SCU+CDU

combine fourTX signal

two step 3dBcombiner

8 low

EDU no combinerdouble duplex 1 middle

Double CDU( with combiner)

no combinerdouble duplex

1 high

Double CDU( without combiner)

combine twoTX signal

double duplex4.5 middle


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Chapter 2 Antenna



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What is Antenna?

Radiate and receive radio wave ,convert high frequency current

to electromagnetic wave when transmitting, and convert

electromagnetic wave to high frequency current when receiving

Blahblahblah bl ah


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Classification

Classify by working band: UHF, VHF, microwave, etc.

Classify by radiate pattern: omni, directional

Classify by structure: line, pane, parabola feed

Classify by polarization: vertical and horizontal

Classify by outline: line and pane


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omni directiondirectional Antenna

Radiate Pattern


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Outline


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vertical polarization

Omni antenna

dual polarization

directional antenna

Polarization

vertical polarization

directional antenna


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Function

Convert high frequency current to electromagnetic wave when

transmitting

Convert electromagnetic wave to high frequency current when

receiving

Antenna can not amplify the transmission power, just concentrate

RF power to one direction

horizontal section Vertical section


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Radiate Pattern

Omni antenna

lobe

Direction

antenna lobe


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Radiate pattern


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Dipole and Isotropic

Dipole

1/4 wave length

1/4wave length

1/2wave length

Isotropic

Ideal radiator with same ability on all direction!


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Gain

The radiation ability of certain antenna overtop dipole or isotropic

Indicates the antenna feature of electromagnetic radiation in specific

directions

Unit: dBi/dBd

theory source

l/2 antenna

Direction antenna

dBd

dBi

dBi =dBd+2.15


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Forward to Back Ratio

The ratio of main lobe signal strength to back lobe

This value is within 1845dB. In urban, it is suggested to use

the antenna with high F/B ratio


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Down title

To control coverage

To decrease inter modulation

Realization: electron and mechanism


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mechanism

electron

Down title


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Effect of Electron Down title

No Down title Electron Down title


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Effect of Mechanism Downtitle

No Downtitle Electron Downtitle


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Effect of different methods

10(E) 10(M)6(E)+ 4(M)


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Polarization

The direction of electro - vector radiated by antenna. The

vertical polarization wave is vertical with the plane of ground,

and the horizontal polarization waves parallel with the plane of

ground

Single antenna has only one polarization direction.

Dual polarized antenna contains two single - polarized antenna

in one entity. Dual polarization antenna usually adopts +45/ 45

degree orthogonal polarization.

-


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Polarization

VERTICAL HORIAONTAL

+ 45 - 45


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Dual Polarization

V/H +/- 45


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Main to lower side

Main to upper side

Upper Side Lobe Suppression


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Coupling Between Antennas

main lobe

5 .. 10

Horizontal separation

Sufficient decoupling distance: 5-10

Antenna patterns become superimposed if

distance is too close

Vertical separation

Decoupling distance:1can provide better RX

/TX decoupling

Minimum coupling loss


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Installation Examples

Recommended decoupling

TX - TX: ~30dB

TX - RX: ~40dB

Horizontal decoupling distance

depends on

Antenna gain

Horizontal rad. pattern

Omni-directional antenna

Use vertical separation for RX and

TX

Use vertical separation (fork) for

RX and diversity RXVertical decoupling is much more effective

0,2m

Omni-directional.: 5 .. 20m

directional : 1 ... 3m


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Antenna Installation

Coupling loss (dB):

Lv=28+40log(k/) (vertical installation)

Lv=22+20log(d/)-(G1+G2)-(S1+S2) (horizontal installation)

: wave length

K: distance at vertical

D: distance at horizontal

G1G2: gain

S1S2: Relative gain at line connected twoantenna


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Distributed Antenna System

BTSBTSPower

splitterPowersplitter

Power

splitter

coupling

coupling

coupling

coupling

Small

antenna

Small

antenna

Small

antenna

Small

antenna

Small

antenna

Small

antenna

Small

antenna

coupling

Dual direction

amplifier

Dual direction amplifier


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Symmetry and Asymmetry Network

Tx /Rx

3

3

3

3

3

3

3

3

3

3

3

Tx /Rx

1.36

0.510

100.5


Dual direction

amplifier


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Optical Fiber Distributed Antenna

The optical fiber repeater is mainly adopted in the case

of wide coverage and long distance transmission

signal

Optical transceiver

Optical transceiver

transceiver

transceiver


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Leaky Cable

Coaxial cable with perforated leads

It is mainly adopted for tunnel, metro and with high cost of

equipment and installing

Tx/Rx

Matching load

Matching load



Power splitter


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Leaky cable

Coaxial cable with perforated leads

Produce constant field-strength along cable runs

Work at wide-band

Radiating loss become higher with high frequency

Very large bending radius

Formerly often used for tunnel coverage

Expensive


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Feature of Leaky Cable

Transmission loss per hundred meter

Typical value : 10~40 dB per 100m

Couple Loss at 1 meter distance

Typical value 55 dB (at 1m)

How to calculate strength with leaky cable?


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Comparison with Distributed Antenna

type leaking fiber coaxial fiber optical

design agility good good not good

cost high low high

Complexity ofinstalling

high low low

loss oftransmission

high high low

power supply not needed not needed needed

reliability high high low

applicability metro, tunnelhigh building,

commercialarea

far areacoverage


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Chapter 2 Antenna



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Tower Top Amplifier

Amplify uplink weak signal, then:

Balance uplink and downlink

Compensate loss of feeder

Simplex TTA duplex TTA triplex TTA


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Triplex Tower Top Amplifier

Low noise amplifier

TX filter

bypassBias TeeBTS

triplexTTA

antenna

DC

RX filterRX filter


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Data Configuration of CDU Turn on power of TTA in CDU before installation

TTA switch is in rear panel of CDU

Configuration alarm threshold of TTA current before installation

TTA current switch is in rear panel of CDU

Configuration attenuation factor of receive signal on consol

attenuation factor of receive signal

=TTA gainfeeder loss

Simplex TTA gain:14dB, triplex TTA gain:12dB

Don t use TTA if not necessary

For the convenience of installation

To get better lighting -proof effect


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Power Switch and Current Limit

Rear panel of KMW CDU

TTAM TTAD

OFF OFF

TTAM TTAD

1

2

3TTAM TTAD

OFF OFF

123

TTAM: power switch of main TTA switch

TTAD: power switch of diversity TTA

select currentlimitTTAM TTAD


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Power Switch and Current Limit

01

2 3

012

3

Note:

MAINmain TTA switch

DIVERSEdiversity TTA switch

Rear panel of COM DEV CDU

01 2

3

012

3

01 2

3

012

3


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Feeder

Feeder s election

Type : 1/27/85/4

Select 5/4 in the case of feeder length is more than 80 m

and otherwise select 7/8 in 900MHz

Select 5/4 in the case of feeder length is more than 50 m

and otherwise select 7/8 in 1800MHz

Feeder curvature should not be so big, outer conductor

should be connected to earth

LG0.251.156.74.47HFC22D -A(7/8 )

6090.31.156.465.874.03SYFY -50-22(7/8 )

ACOME0.221.156.64.3M1474A(7/8 )

ANDREW0.381.154.774.313.172.98LDF6 -50(5/4 )ANDREW0.251.156.465.874.34.03LDF5 -50A(7/8 )

2,0001,7001,000890manufacturerBend

Radius (m)VSWRLOSS dB/100m (MHz)TYPE


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In this course, we have learned:

CUD structure and loss

SCU structure and loss

Antenna type and feature

TTA

Summary


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Documents

OMF000004 Radio Frequency Parts and Antenna-Training-20060531-A-2.0