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ONI WAY

UMTS Site Engineering Guidelines

R : AC.OW.020401.469: 1.00

: 02/04/01

Abstract / Comments

The present document aims at describing the principle radio rules to be applied whenperforming radio site engineering for ONI WAY project.

Author: Alexandre Bresson, Remi Cordon, Naveed Akbar

Documentalist: Documentalist

Approved by: Samuel Ramos

Quality manager: Quality Manager

This confidential document is the property of NORTEL NETWORKS and may not be copied or circulated without permissionCe document confidentiel est la propritde NORTEL NETWORKS et ne peut tre reproduit ou communiqusans autorisation


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AC.OW.020401.469

DOCUMENT AMENDMENTS

VERSION DATE COMMENTS AUTHOR

V01.00 02/04/01 Creation RCO


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UMTS Radio Site Engineering Guidelines Page 2 of 37

AC.OW.020401.469 V1.0 02/04/01

T A B L E O F C O N T E N T S

1 INTRODUCTION........................................................................................................................................ ......... 3

1.1 SCOPE.......................................................................................................................................................... 41 2 CHANGES...................................................................................................... ...................................................... 4

2 RELATED DOCUMENTS ................................................................................................................................ ......... 5

3 ABBREVIATIONS & DEFINITIONS ....................................................................................................................... 5

2 1 ABBREVIATIONS ...................................................................................................................................... ......... 52 2 DEFINITIONS....................................................................................................................... ............................... 5

4 RADIO SITE ENGINEERING ................................................................................................................... ......... 6

4.1 DESIGN SPECIFICATIONS .................................................................................................................................. 64 1 1 Antenna operating band......................................................................................................................... ......... 64 1 2 Antenna beamwidth ............................................................................................................................... ......... 64 1 3 Mechanical design & environmental durability................... ............................................................................ 74 1 4 Camouflage antenna................................................................................. ...................................................... 8

4 2 ANTENNA ORIENTATION ....................................................................................................................................... 104 3 ANTENNA DOWNTILT ............................................................................................................................................ 104 4 ANTENNA POSITIONING ......................................................................................................................................... 13

4 4 1 Antenna pattern distortion due to nearby obstacles ....................................................................................... 134 4 3 Roof top mounting ................................................................................................................................. ....... 134 4 4 Wall mounting ....................................................................................................................................... ....... 17

4 5 SECTOR ORIENTATION................................................................................................................................ 194 5 1 Sector Numbering................................................................................................................................... 194 5 2 MAGNETIC NORTH............ ...... ...... ..... ...... ...... ...... ..... ...... ...... ...... ..... ...... ...... ...... ..... ...... ...... ...... ..... ..... 19

5 MORPHOLOGICAL CONSIDERATIONS ............................................................................................................ 20

5.1 MORPHOLOGY CLASSIFICATION ............................................................................................................................ 205.2 LINK BETWEEN CLUTTERS AND MORPHOLOGIES ..................................................................................................... 21

6. PRACTICAL CO-SITING RULES.................................................................................................................. ....... 22

6.1 GENERAL RULES .................................................................................................................................................. 226.2 COSITING ............................................................................................................................................................. 226.3 COEXISTENCE RULES ............................................................................................................................................ 30

END OF DOCUMENT ..................................................................................................................................... 34


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1 INTRODUCTION

Radio site engineering is one of most important factor to ensure a goodcoverage and low interference of a site.

The present document aims at giving some basic rules and recommendationsfor doing UMTS radio site engineering. It is intended to use as a guideline forradio design engineers who are involved in the UMTS radio design of ONI WAYnetwork.

So, in the present document, the following points are treated:

o Antenna Information related to installation and selection is giventaking into account, antenna tilt, orientation and minimisingantenna pattern distortion due to near filed physical obstacleshave to be considered.

o RF cable, connector, jumper selection.

o TMA and diplexers / triplexers.

o Cositing rules


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1.1 SCOPE

The present document is about macrocell engineering. Microcell and indoorengineering will be considered in future release.It concerns only the UMTS FDD mode.

1 2 CHANGES

Guidelines given in the present document may be subject to changes in thefollowing weeks.

Readers will have to care about the versions


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2 RELATED DOCUMENTS

[R1] UMTS Site Engineering Guidelines -- Laetitia Moussay,

Wang Chunsheng

3 ABBREVIATIONS & DEFINITIONS

2 1 ABBREVIATIONS

ANSI : American National Standards InstituteEMR : Electromagnetic RadiationFCC : Federal Communications Commission

IEEE : Institute of Electrical and Electronics EngineersMPE : Maximum Permissible ExposureNCRP : National Council on Radiation Protection and MeasurementSAR : Specific Absorption Rate

ERP : Effective Radiated PowerEIRP : Effective Isotropic Radiated PowerRF : Radio FrequencyUMTS : Universal Mobile Telecommnication SystemGSM : Global System for MobileFDD : Frequency Division Duplex

TDD : Time Division DuplexBTS : Base StationiBTS : internet BTSTx : TransmitterRx : Receiver

3rd

IMP : 3rd

order intermodulationPIP : Passive intermodulation productVSWR : Voltage Standing Wave RatioTMA : Tower Mounted Amplifier

2 2 DEFINITIONS

N/A


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4 RADIO SITE ENGINEERING

4.1 DESIGN SPECIFICATIONS

4 1 1 ANTENNA OPERATING BAND

The most important factor when selecting antenna is the operating band.The following tables give the transmitting and receiving bands of GSM 900,GSM-R, GSM 1800 and UMTS:

GSM 900 GSM-R GSM 1800

Uplink (Rx-band) 890 915 MHz 876 915 MHz 1710 1785 MHzDownlink(Tx-band) 935 960 MHz 921 960 MHz 1805 1880 MHz

UMTS UTRA TDD UTRA FDD

Uplink (Rx-Band)1900 1920 MHz2010 2025 MHz

1920 1980 MHz

Downlink (Tx-Band)1900 1920 MHz2010 2025 MHz

2110 2170 MHz

UMTS single band antenna is actually working on 1900 MHz ~ 2170 MHz.

Frequencies assigned to Oniway are:

FDD ( uplink) Frequency block from 1950,1 to 1964,9 MHz with the firstcarrier centered in 1952,6 MHz and the last one in 1962,4 MHz. ( FDD 3)

FDD ( Downlink) Frequency block from 2140,1 to 2154,9 MHz with the first

carrier centered in 2142,6 MHz and the last one in 2152,4 MHz.

TDD Frequency block from 1905,1 to 1910,1 MHz with the centered carrier in1907,6 MHz. ( Block TDD2)

4 1 2 ANTENNA BEAMWIDTH

Two beamwidth parameters must be concerned.

Horizontal beamwidth: the degrees when horizontal radiation loss 3 dB.


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Vertical beamwidth: the degrees when vertical radiation loss 3 dB.

The two kinds of beamwidth are very important to the antenna radiation, so theyare also key parameters for the coverage and interference of BTS. RF engineermust be very carefully to select the antenna to fit the right situation.

4 1 3 Horizontal Beamwidth Engineering Rules:

Horizontal beamwidth typical used on GSM 900, GSM 1800 and UMTSsystems are 33o, 65o,85oand 90o.

For tri-sector site application, a horizontal beamwidth between 65o

and 90o

(atthe 3 dB points) is usually specified to provide the right overlap and coverage

area for the suburban and rural areas.For the dense urban, urban and inner city areas, an antenna horizontalbeamwidth of 65

ois considered to be the better choice. Indeed, the excessive

overlap between sectors can be reduced. This results in reducing soft handoff,channel element usage and system noise.

Bi-sector site with two antennas mounting back to back is normally deployedalong the highway in the rural areas. An antenna beamwidth of 65o is usuallyused for highway in the suburban area.

The usage of 65o horizontal beamwidth instead of 90obeamwidth can increase

the link budget by about 1.5 dB, as the antenna gain is better.

Vertical Beamwidth Engineering Rules:

A vertical beamwidth of 4o is as narrow as the antenna is hard to level

accurately. Moreover antenna with vertical beamwidth less than 4ois very easyto suffer from wind vibrations.

4 1 3 MECHANICAL DESIGN & ENVIRONMENTAL DURABILITY

Along with these electrical issues, mechanical issues are also important toconsider. The antenna shouldhave less cables and solder joint in the designsince the soldered joint is hard to control and may break down over long periodof time.

Another key mechanical issue is the antenna connector. The 7/16 Din femaleconnector should be used since it is durable and hard to have inner pin to bedamaged during the installation. If the inner pin is partial damaged, it can causepoor Tx power and create intermodulation.


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Antenna structure and downtilt clamps should be considered. Antenna musthold up to 125 mph wind and it must have the drain hole.

Environmental durability also needs to be considered. When selectingantennas, the environmental testing such as the IEC (International ElectroTechnical) testing must be obtained from the antenna manufacturers. Thefollowings are the minimal IEC testing a manufacturer needs to perform.

IEC Test Code Description

IEC68-2-1 Cold Test: 16 hours at 40o C

IEC68-2-2 Dry Heat Test: 16 hours at +70o C

IEC68-2-11 Salt Mist Test: 48 hours in salt tank @ 5% salt solution

IEC68-2-14 Change of Temperature Test: +70 o C to 40o C two cycles, 2

hours during well.IEC68-2-18 Rain Test: 10mm/hour at various angle.

ICE68-2-26 Vibration: Varied frequencies and multiple axes.

IEC-68-2-3 Humidity Test: 24 hours @ 55o C and 95 % humidity, six cycles.

4 1 4 CAMOUFLAGE ANTENNA

Sometimes, camouflage antenna shall be used to meet environment al

requirements. Camouflage antenna is commonly used when antennas arelocated on historical buildings, for microcells or when the owner of site requiresthem for aesthetic reasons.The camouflage antennas can be ordered individually in varied colours andshapes from Cellwave, Kathrein and other antenna vendors.

Hereafter are some camouflage solutions proposed by these manufacturers.

It is possible to paint the antenna:


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It is possible to integrate pylon and antenna inside a false tree:

It is also possible to include the antenna inside the environment:


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4 2 ANTENNA ORIENTATION

Orientation or the direction of antennas also plays an important role in thesystem RF design. Orientation is the direction of the main lobe of the horizontalantenna pattern and should be pointed in the direction of the main area ofcoverage for the sector under consideration. Therefore, in a built-up area, theantenna should be pointed at the main population (i.e. where the expectedmobile users are), clearing any near field obstructions (such as buildingsdirectly in front of up to 50m) to minimize unwanted reflections.

4 3 ANTENNA DOWNTILT

Downtilt BTS antenna is a key factor for designing and optimising the systemperformance. A BTS with antenna located in a high hill normally createscoverage holes where are closed to the BTS. One way to correct that is toapply mechanical downtilt.

Downtilt the main beam below the horizon can reduce RF signal propagatingbeyond the desired coverage or reduce the RF power blasting to adjacent sitesand to the second tier sites. As a result, system noise, unnecessary softhandoff, pilot pollution can be reduced or controlled.

Downtilt the antenna should be handle with care since very site has specific

height above the average terrain. An estimate value of downtilt can becalculated by using the following formula:


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Figure 3:Downtilt and radiated distance

Main beam distance = H / tan(DT)

Dmin= H / tan(DT + 0.5 * VBW)Dmax= H / tan(DT 0.5 * VBW)

where DT = downtilt angle and VBW = vertical beamwidth.

Three kinds of downtilt are commonly used.

Mechanical downtilt (particularly use in rural or suburban)

Electrical downtilt (particularly use in urban)

Both of mechanical and electrical downtilt

The antenna with fixed electrical downtilt is a good solution to optimise the highBTS located in urban area. It can provide a better performance: good coverageand low radiation distortion.

See the below example in figure 4, here the antenna height is 30m, comparingmechanical and electrical downtilt with 0o, 6 o, 8 oand 10o. The radiation of the

Height (H)

Downtilt angle (DT)

3dB vertical beamwidth(VBW)

Main

radiated

area

Dmin

Dmax


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antenna with electrical downtilt is not distorted whereas the antenna withoutelectrical downtilt is distorted when the mechanical downtilt is more than 8o.BTS which requires mechanical downtilt with more than 6

o should be verified

whether the bore side of the horizontal pattern is distorted.

Figure 4: Comparison between mechanical and electrical downtilt

Electrical downtilt can be used in conjunction with mechanical downtilt for betterresult since electrical downtilt only affects on the horizon but not the two sidesof the horizontal pattern. Therefore, if mechanical downtilt requires more than8o, it is suggested using both mechanical downtilt and electrical downtilttogether.


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4 4 ANTENNA POSITIONING

4 4 1 ANTENNA PATTERN DISTORTION DUE TO NEARBY OBSTACLES

These are the surrounding physical obstructions in the vicinity of an antennathat could affect the antenna pattern, which in turn would cause shadowing andreflections of the signal that is transmitted or received by the particular antenna.It is a common practice to clear the antenna pattern (main lobe) fromobstruction within 50 m (minimum of 30 m) and possibly more whereverapplicable.

A site should be chosen so that adjacent sites are of similar height 5m. Highsites amongst a number of low sites must be prohibited.

Besides antenna height should be at minimum 3 meters above surroundingclutter height (buildings, trees) and at maximum 10 meters above surroundingclutter in urban and dense urban environments. In case a candidate site is toohigh then it is recommended to consider the antennas implementation part waydown the building i.e. on the faades.

4 4 3 ROOF TOP MOUNTING

With roof top mounting, the major obstacle is the roof itself. There is a risk ofshadowing and antenna radiation pattern distortion if the antenna is mountedtoo closed to the roof top. Therefore, the antenna has to be installed at a certainheight above the roof or other obstructions, to clear the antenna pattern.Consequently, if the antennas are mounted on the roof top closed to the roofedge, less height is required to clear the shadowing effect. On the other hand,the antenna height above the roof top has to be increased if the antenna ismoved away from the edge.


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When antennas with downtilt are mounted on roof tops, extra clearance determined by thesum of the electrical and mechanical downtilt has to be kept in addition to the half verticalbeamwidth of the antenna main lobe to minimize shadowing due to the roof.

Forecasting the optimization phase, the RF engineer has to consider a margin in the actualdowntilt only to calculate the minimum mast height.

In order to meet the requirement of no distortion of main lobe, following values shall be used

verticalbeamwidthat 3dB

Figure 12: Beamwidth, downtilt and obstacle

1.01.2

1.31.5

1.7

1.92.1

2.32.5

2.72.9

3.23.4

3.63.8

4.04.2

4.44.6

4.9

1.01.2

1.41.7

2.02.2

2.5

2.83.0

3.33.6

3.84.1

4.44.6

4.95.2

5.45.7

6.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

D : Distance to buildding edge (m)

h:Minimumhe

ightofantenna'sbottom(

m)

Rural, Suburban Urban, Dense Urban

Extraclearance for

D

h


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For what concerns the horizontal beamwidth, it should be cleared from closedobstacles by 120 around the antenna azimuth for a H65 antenna.

Besides one should make sure that the main lobe is free of obstructions. Twotypes of obstacles have to be considered:

- Obstacles in the radiating near field. In this field obstacle may distort theantenna pattern

- Obstacles in the radiation Far Field: when the distance to the antenna exceeds

(2xd2/), obstacles do not distort antenna pattern but reduced the coverage area.

d : antenna length

: wave lengthwith d=1.3m we are in the radiating far field when the distance to antennaexceeds 22m. So radio planners should check if obstacles in the radiating farfield do not gravely reduce the coverage area.

120 horizontal clearance


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4 4 5 1 Recommend ed Down Ti l ts

As a general rule, during the nominal plan phase following electrical down tiltare recommended.

Table 53-1: Recommended Tilts

Morphology Down Tilt Values

Dense Urban 6

Urban 4

Suburban 2

Rural 2

Due to close intersite distance in dense urban environment and the criticalnature of high data rates services, a 6-degree electrical tilt is required. This ismainly to avoid potential pilot pollution problems in the network. However, down

tilts in above indicated environments will be further analyzed on case-by-casebasis during the nominal plan phase and network deployment.


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4 4 4 WALL MOUNTING

Directional antennas could be both roof top and wall mounted depending on the

specific requirement. In the case of wall mounting, the degree of distortion ofthe antenna pattern caused by the reflection of the back lobe will depend on thefront to back ratio of the antenna and the angle at which the back lobe hits thewall. For antennas with front to back ratios better than 25 dB, the risk of beamdistortion due to reflections is low.

Considerations are taken with respect to the direction of the antennas.

The ideal direction is when the antenna is perpendicular to the wall. See thefigure 13.

Figure 13:Wall mounted antenna

If the antenna has to be mounted in a non-perpendicular direction to the wall toachieve the desired orientation, it is important to clear at least half the 3dB

beamwidth of the antenna horizontal pattern on either side, to minimiseshadowing due to the wall. So, a safety margin of 15 should be added on bothsides of the sector borderlines, then having +/- 75 (for a standard 120cell)free, there is no risk for shadowing effects and beam distortion due toreflections (see figure 14).

Wall

antenna

Antenna direction


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Figure 14:Keep clear for radiation direction of wall mounted antenna

If antenna with narrower horizontal patterns (< 80) is used to cover 120sectors, an extra safety margin (>15) has to be allowed on either side.In the same way, if the antenna is closed to a corner of the wall and if antennais mounted at a certain distance from the wall, then more than 15 can beacceptable as long as the cell sector including the safety margin is free from thewall. See the figure 15.

Figure 15: Keep clear for radiation direction of wall mounted antenna with

downtilt

Wall

antenna

Antenna direction

Maximum 15

Radiation angle

=60

Wall

antenna

Antenna direction

Radiation

angle =60

More

than 15


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4 5 SECTOR ORIENTATION

The standard sector orientation to be adopted will be 0,120,240 degrees, usingnorth as reference. However, these sector orientation are can be furthermodified to meet specific coverage objectives and to avoid generation of pilotpollution.

4 5 1 SECTOR NUMBERING

When assigning sector numbering scheme. Following rule should

always be used. Site sectors should be numbered clockwise startingwith 0 Magnetic North for sector 1. Regardless of sector orientation andnumber of sectors, the sector numbering should always with 1. Evenwith two sectored sites, same rule should be used. For instance a twosector site with sector orientations 110 and 270, sector numbering willbe Sector 1oriented 110 and Sector 2 oriented 270.

4 5 2 MAGNETIC NORTH

Its agreed that the sector azimuths should be referenced to Magnetic North inall documentation (TSSs, SARs, SVRs, etc) and in all measurements on thefield.Only in Planet, all the sector azimuths should be updated with less 5(Cartographic North).


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5 MORPHOLOGICAL CONSIDERATIONS

When designing a wireless system, network layout and specific site placementshould consider in detail the local signal propagation environment. Formodeling purposes, it is important to classify different environments asmorphologies, for a propagation model to interpret. It is also important for thedesign engineer to understand the limitations of these classifications and to beable to make site-specific adjustments later in the design process asappropriate. This section presents the morphological type of site classifications.

5.1 MORPHOLOGY CLASSIFICATION

OverviewMorphology determination is based on the detailed UMTS network planninganalysis (UMTS service distribution) and associated link budget parameters.Indeed the maximum allowable path loss can be determined by:1- choosing the desired service2- determining the terrain morphology and therefore the allowable path loss.

This document categorizes the various morphology classifications to be usedfor design of ONIWAYs UMTS system. Each list prioritizes characteristicsdetermined to be indicators for that particular morphology class.Morphological characteristics of a given area were determined using the

following methods:1. Map studies2. Population density3. Visual observation4. Photography

Obviously, the classification of morphology can be somewhat objective. Theseguidelines should serve to eliminate most uncertainty in making classifications.

Dense Urban

Dense urban morphology is characterized as follows: Locat ion mostly core business district or downtown metropolitan area

Populat ion high business population; low residential population

Bui ld ings mostly skyscrapers and tall buildings (10 stories) in closeproximity; i.e., within a city block

Roadways narrow streets and alleys

Traff ic very high volume during peak hours

UrbanLight urban morphology is characterized as follows:


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Locat ion proximal to downtown area of larger cities

Populat ion medium to high business population; low to mediumresidential population

Bui ld ings

Roadways mostly narrow streets and alleys

Traff ic high volume, especially during peak hours

SuburbanSuburban morphology is characterized as follows:

Locat ion suburbs and outlying mid-sized cities

Bui ld ings mostly 1 3 story structures sparsely distributed; stripmalls; occasional high-rise

Populat ion medium to high residential population; lower businesspopulation

Roadways many wide streets

Traff ic low-medium volume; higher during rush hours

RuralRural morphology is characterized as follows:

Locat ion farmland, open area, isolated roadways, small towns

Bui ld ings mostly 1 2 story dwellings; sparsely located

Populat ion low residential population; almost non-existent businesspopulation

Roadwaysfreeways and long roadways

Traff ic low volume; higher at major highway intersections to and frommajor cities

5.2 LINK BETWEEN CLUTTERS AND MORPHOLOGIES

CLUTTER Morphology

Open Rural

Sea/Inland Water Rural

Old Dense Urban Dense Urban

Residential Suburban

Mean Urban UrbanDense Urban Dense Urban

Building Urban

Village Rural

Industrial Suburban

Open in Urban Rural

Forest Rural

Park Rural

Inland Water N.A.Mean urban Lisbon Urban


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Dense block building Dense Urban

Scattered Urban Urban

6. PRACTICAL CO-SITING RULES

6.1 GENERAL RULES

Oni Way antennas shall not be placed in front of the main lobe of any other operatorantennas, as well as there should be no GSM antennas in the main lobe of the Oniway

antennas. Always when possible Oni Way antennas shall be placed higher than the other operator

antennas, if that doesnt compromise the site in terms of interference issues

Always when possible Oni Way antennas shall be installed on buildings faade, if that doesntcompromise the site in terms of coverage

Never shall be installed antennas pointing to each others

The most constraining decoupling between antennas needed is 60dB. All the followingconsiderations will be based on this value. It has to be noticed that depending on the kind ofBTS present on the roof, this necessary decoupling can be drastically reduced.

For all configurations that are not included in the following rules, specific studies must be doneand cositing measurements performed if necessary.

There are two cases depending on the GSM/UMTS antennas distance :less than 20 m => cosi t ing ru lesmore than 20m (above the Fresnel area) => coexistence rules

6.2 COSITING

These rules are mostly used when GSM antennas are on the same rooftop/tower asthe UMTS one. The values are coming from measurements.

Vertical Antenna Decoupling

Vertical antenna decoupling shall, when physically possible, always be used, because its theeasiest and less problematic way to achieve better decoupling.

This decoupling method has the better immunity against normal changes on other operatorsantenna system.

This method is easiest applicable on tower sharing, if available height for antenna placementdoesnt compromise site objectives.

This method shall be applied also when antennas are positioned back to back

The separation between antennas (Bottom of the highest to the top of the lowest) depends onthe frequency bands :


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GSM 900

UMTS : H = 1mGSM 1800UMTS : H = 2m50

Dual Band

UMTS : H = 1mThese values are based on measurements with UMTS antenna

below GSM one, so we can considered H =1m50 for GSM1800

UMTSwhen UMTS antenna is above the GSM one ( and if GSM is not uptilted).

Note : When there is an azimuth divergence of 90 between the antenna,1m separation is enough also between GSM1800 and UMTS.separation is enough also between GSM1800 and UMTS.

GSM 900

Hmin = 1 m

For the bestdecoupling theUMTS antennashould be thehigher one

GSM 1800

Hmin = 2.5 m

1.5m if the UMTSantenna isabove the GSM

1m if theazimuth have adifference of 90

DUAL

Hmin

= 1 m

//

Vertical Antenna Minimum Height


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Horizontal Antenna Decoupling (Buildings)

This method to decouple antennas shall be used only when is not possible to use the Verticalone

Oni Way antennas shall be placed taking into account the other operators antennas azimuthand Horizontal beamwidth

The decoupling achieved with this kind of installation will depend on the other operatorantenna bearing changes. To avoid this problem an agreement with them on these rules shallbe done.

The separation between antennas (Side to Side) depends on the frequency bands :GSM 900UMTS : D = 1mGSM 1800UMTS : D = 1m50

Dual Band

UMTS : D = 3mNote : Mix decoupling (Horizontal & Vertical) provide the necessary isolation for GSM1800 and dual band antennas

When GSM antennas are 90H, 0.5m of margin had to be take.

See Annex1 for azimuth to be take for the different antenna, and Annex 2 to take in considerations the antennaspresent on the rooftop.


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Vertical & Horizontal Antenna Decoupling

GSM 900

Hmin = 0.5 mDmin = 1mH >= D/2

This value isobtained for amax verticalaperture of

20and amaximum tilt of12

GSM 1800


//

Dual Band


//D


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ANNEX1 GSM 900 60 dB of horizontal isolation chart

Area 1 is forbiddenArea 2 azimuths 0 to 180Area 3 azimuths 60 to 240Area 4 azimuths 90 to 270Area 5 : mix decoupling area (vertical + horizontal)

N.B. : The large circle represent the margin for H90 antennas; and thebold line the limit between area 2&5 for these antennas


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GSM 1800 60 dB of horizontal isolation chart




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Dual Band 60 dB of horizontal isolation chart




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ANNEX 2: Situation 1 :The other operator has separated poles, one foreach antenna

Situation - 2: The other operator has a single pole or tower with 3antennas

- Maximum azimuth rotationallowed to the left or to the right

- Other o erator 90H beamwith antennas GSM900 /

-

Examples: 2 = 90

=> = 45

Examples: 2 =

90 => = 45


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6.3 COEXISTENCE RULES

These rules are used when GSM antennas exist on another building close to thecandidate, or on another tower. At a distance higher than 20m, we can use the PathLoss formula to calculate the decoupling between the 2 antennas. Obviously, thesecalculations dont include possible obstacles that will increase the decoupling value.

To get the 60dB of decoupling, different parameters can be modified :

UMTS antenna azimuth

UMTS antenna height

Distance between antennas

Tilt

Relative Azimuth between the GSM and UMTS antennas.

UMTS antenna

GSM antenna

NORTH

Relative azimuth

UMTS azimuth

GSM azimuth

The coexistence.xls Excel spreadsheet is used to calculate the decoupling

Some examples are given below, starting with a basic configuration and changing one

parameter each time :


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Hypothesis:

GSM/UMTS Antenna Gain :18dBFeeder Losses : 3dB

Case 1 :

Existing GSM tower;Azimuths: 0,120,240Height: 30mTilt : 0

UMTS towerAzimuths : 0,120,240Height : 30mTilt : 0Distance from existing : 30mRelative Azimuth : 270

The main constraining sectors are 120 GSM vs 240 UMTS.

Decoupling value : 44,3 dB

To improve this value, we can change one by one the different parameters of theUMTS tower to reach the 60 dB.

Case 2 : Change in Height

With 2.5m more or 2.5m less on the UMTS antenna height (27,5m or 32,5m), thedecoupling is 67,1dB.

0

120240

0

120240

30m

GSM UMTS

27.5m

30m OR

32.5m

GSM

UMTS

30m


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Case 3 : Change in distanc e

60dB of decouplingcan be obtain only by spacing the towers with more than 183m !

Case 4 : Change in tilt

By keeping the GSM antenna tilt at 0, a 7 tilt on the UMTS antenna provide 61,3 dB ofdecoupling.

If the GSM antenna has a tilt of 5, 5 tilt on the UMTS is enough to provide 63dB of decoupling.

Case 5 : Change in azimu th

For 60dB of decoupling, the 240 azimuth needs to be change to 0 or to 175.This could imply a major change in the design, and therefore it is not recommended in this case.

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AC.OW.020401.469 V1.0 02/04/01

Case 6 : Change in relat ive azimu th

To reach 60 dB of decoupling, the relative azimuth has to be changed from 270 to 210 or335.

In this case there is no more problem between GSM 120 and UMTS 240, but a new one emergebetween GSM 0 and UMTS 240 or between GSM 120 and UMTS 0, so it is also notrecommended.

Conclus ion

In this example, the most efficient decoupling way is changing the height of the UMTS tower.

On the field, a mix between the different parameters will allow to reach the 60dB of decoupling.

Case 8 : Azimu ths facing each other.

Another interesting case in when GSM and UMTS sectors are facing each other.

The conditions are :GSM/UMTS antennas heights : 30mAzimuth : GSM : 270; UMTS : 90Relative Azimuth : 90Tilt GSM, UMTS: 4Distance : 30m

In this case, the decoupling is 48,8 dB.

To reach 60dB, the UMTS antenna height must be 4m above or below the GSM one.An other possibility is to put the UMTS antenna 2m below, with a distance of 45m and a 6 tilt.

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