Training book－Communication Principle NEC Microwave Communication Principle & design

Ver.2.2

Training book－Communication Principle

NEC

Microwave CommunicationPrinciple & design

Training book－ NEC Copyrights

1. Application & construction

4. Multipath fading & countermeasure

5. Frequency plan

3. Path clearance requirement

7. Review & summary

6. Design flow chart

2. Microwave propagation character

CONTENTS


Terminal

Digital transmission system:

Promised information transmission

Reliability / Efficient / In time

Typical communication system

: Transmit / received the information & instruction

Exchange

Terminal

Exchange : Reroute the information

such as IP switch / PABX/ ATM switch

Exchange

Exchange

Exchange Exchange

Exchange

Exchange

Exchange

Terminal


Various transmission methods

Satellite

Fiber-optics cable

Radio link

Coaxial cable

Exchange Exchange


2MB SDH

[ Drop & Insert ][Repeater]

radio SDH SDH 2MB

SDH

[FOTS]

2MB

Various application

Case 1 Mix with FOTS

radioradio

SDH : SDH Multiplex Equipment

radio radio radio

radio : Microwave Radio Equipment FOTS : Fiber Optics Transmission System


SDH SDH2MB 2MB

[FOTS]

Various application

Case 2 Protection for the FOTS


radio : Microwave Radio Equipment FOTS : Fiber Optics Transmission System

radio radio radio radio radio radio


radio

radio

SDH

63x2 MB

STM-1 RING

radioSDHradio

Various application

Case 3 Ring protection

Same as above

Same as above


radio : Microwave Radio Equipment

3→11→3

W

W

3→11→3

P

P

SW

SW

3

2

1

4

3→11→3

3→11→3

SW

SW

Failure

3

2

1

4

Note: Microwave as transmission mediaSNCP Ring protection function realized in MUX.

STM-1STM-4 Ring


BTS

Cellular/UMTSNetwork

BTS

BTSBTS

BTS

BTS

BTS STMSTM--1 Ring1 Ring

STMSTM--0 / PDH Approach0 / PDH Approach

BTS

Application for cellular network


Main strongpoint of microwave

Overcome the topography difficulty such as mountain & river

Less Immune to natural disasters such as flooding & earthquakes

Avoid the trouble of accidental damage such as building and road construction works

Easier Single Point Security Protection such as against subversive terrorist


Main strongpoint of microwave

Faster in Service Implementation & Easy Maintenance

Compatible with the Existing Infrastructure（Site building, Tower etc.)

Radio grows with the network: Easily expandable and accommodates future relocation

Avoid the trouble to borrow the land from the private owner


Outlook of microwave room:

Concrete

Guy-support

Self-support

Microwave roomRoof mount


ODU

IF cable or waveguide

Tower

Cable clamp

Antenna bracket

DDF/LDF

LDF & DDF

Antenna

PBD

IDU

ETSI

Cable rack

Construction of micro room

Side view


Construction of micro room

Outdoor cable rack

Through wall hole

Groundingcable

Signal cable

Power cable Microwave

room170mm

170m

m

68.6mmWeight = 3kg

IDU

ODU

Top view


1

432

1

432

4E11

432

1

30

34,368 Mbit/s

8,448 Mbit/s

2,048 Mbit/s

64 kbit/s

8.448 Mbit/s E2

2/34 Mbit/s PDHADM155

155.520 Mbit/s STM-1

16E1

PCM2,048 Mbit/s E1

34.268 Mbit/s E3

139.264 Mbit/s E464E1PDH

Digital system hierarchy

SDH




5. Frequency plan


7. Review & summary



CONTENTS


Electromagnetic wave

E

H

Direction of propagationZ

Y

X

Electromagnetic wave & polarization

Narrow side

Wide side

Electric field distribution

Rectangular waveguide cross section

V (vertical) polarization

H (Horizontal) polarization


Radio frequency allocation

30 KHz 300 3MHz 30 300M 3GHz 30 300G 3 T Hz

10Km 1 100m 10 1 100mm 10 1 100μm

VLF

Very-long

LF

long

UHF

Ultra-high

VHF

very-high

MF

middle

HF

short

SHF

super-high

EHF

optical

Band

Wavelength

Sub-band

Mainapplication

voyage

Raido voyage

broadcast broadcast FMbroadcastT VT V

T V satellite

Micro-wave

repeater

Microwavespectrum


Features of microwave transmission

1. Line of sight propagation (LOS)

○ Select the station with high elevation

○ Add the repeater or shorten the distance


Features of microwave transmission

2. Reflection, refraction , diffraction and scattering etc.

Reflection

Refraction Diffraction

Scattering

○ Multi-path fading○ Raining & snow attenuation (Above 10G)




5. Frequency plan


7. Review & summary



CONTENTS


1st Fresnel radius ：F1

d1 d2

d

d

T R

P

2λ

+=+ dPRPT

22 λ+=+ dPRPT

N Fresnel radius：

Fresnel zone introduction

dfdd

ddd

F⋅⋅⋅

=⋅⋅

= 2121 3001

λ

dfddn

dddn

Fn⋅

⋅⋅⋅=

⋅⋅⋅= 2121 300λ

Earth

1st Fresnel radius

2ndt Fresnel radius

Direction wave

Reflection wave


Line of Sight

Line of sight

Near LoS

None LoS


Calculation of Path Clearance

： Actual Earth radius 6370Km( ) hskRddhh

ddhhc −−−−=

02212111 0R

hc

hs

2h

1h

1d 2dd


1.0 F1 at K=4/3

0.577 F1 at K＝2/3 (When flat terrain)

0 F1 at K＝2/3 (When obstacle is ridge)

0.3 F1 at K＝2/3 (When obstacle is not ridge)

Path clearance criteria

For main antenna For S/D antenna

0.6 F at K = 4/3

* F1 is the first Fresnel Region


Constructionheight

Example

? ? 11 08

NEC CORPORATION

LuwubeLatitude 00 45 51.20 NLongitude 032 33 12.60 EAzimuth 352.14�Elevation 1287 m ASLAntenna CL 35.0 m AGL

KalubangaLatitude 01 19 24.90 NLongitude 032 28 36.30 EAzimuth 172.14�Elevation 1161 m ASLAntenna CL 35.0 m AGL

Frequency (MHz) = 7425.0K = 1.33, 0.67

%F1 = 100.00, 60.00

Path length (62.44 km)0 5 10 15 20 25 30 35 40 45 50 55 60

Elev

atio

n (m

)

1040

1060

1080

1100

1120

1140

1160

1180

1200

1220

1240

1260

1280

1300

1320

1340

1360

K=4/3

K=2/3

100%Fresnel Zone

Hc K=4/3

Hc K=2/3

60%Fresnel Zone


Countermeasure for the insufficient LOS

By means of Google earth softwarecheck the construction condition especial in urban


Countermeasure for the insufficient LOS

Field survey the path along the linkconstruction height/site coordinate

Re-routeAvailable adjacent sitecoordinate/ tower height

Adding the microwave repeater stationnear the road/ with high elevation


Near field requirement for Antenna

D

1 m

1 m 20 °

20 °

10 D

17.1 D2 /λ

D：antenna diameter，m




5. Frequency plan


7. Review & summary



CONTENTS


Received level variation with time changing

What’s fading

fadingMulti-path


SD (Space Diversity)

H

○ More antenna installation○ Considered tower workload

Multi-path fading independent in space

Measure against Fading

Main path

SD path


1+1 Hot-standby

SD application


FD (Frequency Diversity)

F2 path

F1 path

Multi-path fading independent in enough frequency space

○ More frequency point needed

Example : 1+1 twin-path /N+1

Measure against Fading


1+1 Twin-path

FD application

2 single polarization antenna 1 dual polarization antenna


FD & SD Hybrid configuration

1+1 Hybrid Diversity




5. Frequency plan


7. Review & summary



CONTENTS


frequency plan shall be conformed with ITU - R

U4GHz Rec. ITU - R F. 382 - 74 GHz Rec. ITU - R F. 635 --4

5 GHz Rec. ITU - R F. 1099--2 L6 GHz Rec. ITU - R F. 383 - 5

U6 GHz Rec. ITU - R F. 384 - 6

L7 GHz Rec. ITU - R F. 385 - 6U7GHz Rec. ITU - R F. 385 - 6L8GHz Rec. ITU - R F. 386 - 511GHz Rec. ITU - R F. 387 - 713GHz Rec. ITU - R F. 497 - 515GHz Rec. ITU - R F. 636 - 318GHz Rec. ITU - R F. 595 - 3

Frequency recommendation


XS：Adjacent frequency separation on the same polarizationYS：Center gap frequency of the go and return channelsZS: Guard Band DS: TX/RX Duplexer Spacing

XSDS

YS

ZS

Frequency recommendation specification

Fo

Fo: Center frequency


Example

Site A Site B Site C Site DU7GHz band

ITU-R Rec.385-6 Annex 3(7,110 - 7,750 MHz)

7121

1'

7177

7233

7275

7317

7373

7429

1

2

3

4

5

f0

2'

3'

4'

5'

1V

3V

1'V

3'V

7149

7205

7345

7401

2H

2'H

2V

4V

2'V

4'V

1H

1'H

1H

1'H

3H

3'H

XS

YS

DS


85432 10 201 30 40 50

1.5

Public access network

Backbone transmission network

Regional & local transmission network

2G/3G

P-MP

Bluetooth

STM-1/XPIC

STM-1/ 16E1/4E1

3.6

GHz

11 GHz

Microwave frequency application sketch

high frequency band / abundant frequency point

P-P(SS)


Priority adopt the high frequency bandabundant frequency point available

Priority adopt the vertical polarizationless the raining attenuation affection

Avoid the same frequency band TX High & Lowviolation in the same station

Reduce the internal frequency interference Overreach interference & Front-back interference

Key factor for frequency allocation plan


Avoid TX High & Low violation

Tx: LowTx: HighTx:High & LowTx: Low


Example

Tx: LowTx: HighTx: LowTx: High


Internal frequency interference analysis

θ

D

U

TXcSite A

Site B

Site C

Ant.BTXa

○ Changing polarization every hop○ Changing frequency point○ Increasing the link angle

Front to back interference

H

V


TXa

45°

=45.3 – 53 =- 7.7 dB

=45.3 – 70 =-24.7 dB

Radiation Pattern Envelop of Antenna

Example: Antenna Gain: 45.3 dB (HPX10-77) H polarization H polarization

Antenna gain in this direction

H to H

Antenna gain in this direction


Internal frequency interference analysis

○ Changing polarization every 2 hops ○ Changing frequency point○ Increasing the link twist

Overreach interference

Site A

Site B

Site C

Site DD

U

θtθrAnt.A

Ant.D

H H

V


CH1 CH3

CH2

CH5 CH7

CH4 CH6 CH8

CH1’

Frequency point & polarization arrangement

interval channel co-polarization

Adjacent channel different polarization


CH1

Co-channel Cross-polarization

CH3 CH5 CH7

CH2 CH4 CH6 CH8

CH1’

Frequency point & polarization arrangement

Antenna: HXPD

Equipment: XPIC technology




5. Frequency plan


7. Review & summary



CONTENTS


Key design value: Flat Fade Margin (FFM)

Threshold

Designreceivedlevel

Flat Fading Margin


AntennaG1

Waveguide

Branching (filters + circulators)

Transmit power: Pt dBm Receive power: Prn dBm

G2

RxTx

Prn (dBm) = Pt (dBm) + G1 (dB) + G2 (dB) - F.S.L. (dB) - Losses (dB) (Waveguides + Branching)

D Km

Free Space Loss = 92.4 + 20log f (GHz) d (km) (dB)

Key design value: Flat Fade Margin (FFM)

FFM (dB) =Prn (dBm) - Threshold (dBm) FFM normal requirement > 35 dB


24 dPt

π

Power per unit area:

tP

d

Free Space Loss definition


G1 =

IF cable

Transmit power: Pt dBm

G2=

RxTx

Prn (dBm) = 25+41+41-138.2-0 = - 31.2 dB

15 Km

Free Space Loss = 92.4 + 20log f (GHz) d (km) (dB)

FFM (dB) =Prn (dBm) - Threshold (dBm) =31.2 – (-88.0) =56.8 dB

Example

Equipment type : 13G 4E1 1+0

Threshold : -88.0 dBm

41dBi

Cable & connect loss = 0

25dBm

20* log (13*15) = 45.8

F.S.L. (dB) = 92.4 +45.8 = 138.2 dB

41dBi


Enter Customer Data

Calculated clearance satisfy

specification?

Calculate SESR & unavailability

Performance meet customer’s requirement?

Station coordinate & Rain zone

& Available frequency

Adjust antenna height& Re-route

& Adding repeater stations

Modify antenna sizefrequency band, or re-routeEquipped with SD or FD

No

Yes

No

Yes

BOQ

Design software tools: Pathloss

Calculated clearance satisfy

specification?

Existing the F-B or overreach interference ?

Adjust frequency point/frequency band

/polarization

Yes

No


Example

Step 1 : Get the relative information Site nameCoordinateE1 requirementtower height

Step 2 : Input the information to Pathloss

Step 3 :Link the site to BSC


Example

Step 4 : Check each hop LOS

LOS is not OK


Example

? ? 06 08

NEC CORPORATION

Site 5Latitude 11 21 41.60 NLongitude 029 44 55.20 EAzimuth 143.72�Elevation 572 m ASLAntenna CL 50.0 m AGL

Site 9Latitude 11 00 04.89 NLongitude 030 00 58.19 EAzimuth 323.77�Elevation 529 m ASLAntenna CL 50.0 m AGL

Frequency (MHz) = 7425.0K = 1.33, 0.67

%F1 = 100.00, 30.00

Path length (49.41 km)0 5 10 15 20 25 30 35 40 45

Elev

atio

n (m

)

480

500

520

540

560

580

600

620

640

660

Site5—site 9 profile


Example

Step 5 : add the microwave repeater

Step 6 : Adjust the frequency allocation

Step 7 : Adjust antenna size & FD & SD


Review & summary

1, Microwave spectrum band300MHz-300GHz

2, Features of microwave transmissionLine of sight propagation (LOS)

Reflection, refraction , diffraction and scattering etc

3, Measure against Fading

4, Internal frequency interferenceDue to the Tx High / Low alternate configuration

5, Key design value: Flat Fade MarginFront to back interference / Overreach interference

FFM (dB) =Prn (dBm) - Threshold (dBm)

FD/SD/low frequency / short distance/ increase antenna size

Training book－Communication Principle NEC Microwave Communication Principle & design

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Transcript of Training book－Communication Principle NEC Microwave Communication Principle & design