PlanningGSM Rio Part2 New

7/29/2019 PlanningGSM Rio Part2 New

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Rio de Janeiro, 19-21 October 2005

FPLBRA1TIM

Introduct ion to GSM/EDGE Radio Planning

Part 2: GSM/EDGE radio planning


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2Michele Ludovico GSM/EDGE Radio Network Planning

FPLBRA1TIMRio de Janeiro,

19-21/10/2005

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Overview

Part 1: GSM/EDGE radio dimensioning:

Link Budget

Uplink/downlink dimensioning

C/I and cluster frequency planning

Erlang capacity estimation

Impact of EDGE deployment

Part 2: GSM/EDGE radio planning: Overview of planning process

Site positioning criteria

Geographic Data Base

Coverage Estimation (EM engines) Channel Dimensioning

Frequency planning

EDGE deployment

Hierarchical structures


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GSM/EDGE Planning ProcessSite Positioning

Site Positioning

Coverage Prediction

Coverage Prediction

Best Server Map

Building

Best Server Map

Building

Quality Analysis

Quality Analysis

Interference Table

Building

Interference Table

Building

Traffic Spreading

Traffic Spreading

Frequency Plan

Definition

Frequency Plan

Definition

Adjacences

Definition

Adjacences

DefinitionCells Dimensioning

Cells Dimensioning


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Outputs of the Planning ProcessOutputs of the Planning Process

How Many Cells?How Many Cells?

Coverage and

quality performance?

Coverage and

quality performance?

f1 f5 f9

f6f8

What ARFCNs

in each Cell?What ARFCNs

in each Cell?

3 Channels:

2 Channels:

How many channels

in each Cell?How many channels

in each Cell?


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GSM/EDGE Planning ProcessSite PositioningSite Positioning

Coverage PredictionCoverage Prediction

Best Server Map

BuildingBest Server Map

Building

Quality AnalysisQuality Analysis

Interference Table

BuildingInterference Table

Building

Traffic SpreadingTraffic Spreading

Frequency Plan

DefinitionFrequency Plan

Definition

Adjacences

DefinitionAdjacences

DefinitionCells DimensioningCells Dimensioning


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Site posit ioning criteria (1)

A regular layout maximizes spectral efficiency and guarantees a deepercontrol on network performance. This is often unfeasible, because of

Irregularity of terrain (orography, sea)

Dishomogenity of offered traffic (leading to

different site density requirements)


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A regular layout maximizes spectral efficiency and guarantees a deepercontrol on network performance. This is often unfeasible, because of

Regulatory constraints

(electromagnetic emission limits,

safety volumes)

Complexity of urban environments


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Besides constraints, theselection of optima sitepositions comes from trade off

between interference andcoverage characteristics.

In the first phases of networkroll-out, coverage is the

principal concern selectionof sites in dominant positions(umbrella sites)

In a mature network context the

presence of umbrella sitesleads to a worse frequencyreuse and, therefore, to a lowercapacity.

F1

F1

F1 F1 F1x x x


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Geographic database

Sources:

Resolution

Structure

Raster (matrix on pixel basis) Vectorial

satellite remote sensing aerial photography

scannerization of paper maps

territorial survey

BuildingDensity

Roads

Population

Density

DB


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Geographic database (raster data creation)

Typical Pixel Size (Resolution)

10 X 7.5 (~ 230 X 230 m)

4 X 3 (~100 X 100 m)

2 X 1.5 (~ 46 X 46 m)

1 X 0.75 (~ 23 X 23 m)

Land sampling and digitalization:


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Geographic database (raster layers)

Altitude (50m)

Building % (50m)


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Geographic data base (vectorials layers)

Buildings

profile

Roads


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Geographic data base

(vectorials layers creat ion)

From Aero Photo Survey To Digitalization


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Best Server Map


Building


Interference Table


Building


Frequency Plan


Definition

Adjacences




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Electromagnetic Engines

Allow the planner to estimate and visualize the coverage areaof each cell in the network

The coverage area is typically evaluated considering the

downlink and calculating the levels of received power (orelectromagnetic field) generated by a base station in the

surrounding area

A value of EM field is calculated for each pixel (coverage canbe represented as a raster layer)

Propagation models, cell parameters and geographic

databases represent the fundamental bricks of any cellularplanning process (for any system, for any generation)

An effective network planning requires reliabilty andaccuracy of data and models


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EM Engines: the idea l approach

Complete evaluation of EM fields usingfull 3D description of buildings andterrain (1m resolution.)

Tipically usedonly for evaluatethe conformity ofinstallations with

respect to exposure

limits for EM fields

Problem: computingtimes and storagerequirements


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Evaluat ion of Coverage AreaEvaluation of Coverage Area

PointPoint--toto--point field strength predictionpoint field strength prediction

Interpolation

Average

Coverage layer

RBS Angular step Linear step

Maximum distance


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Cell typology definit ionCell typology definit ion

Macro

Over close

obstacles

Up to 20-30 Km

Urban

Suburban

Rural

Small

Comparable to

close obstacles

Several Km

Urban

Suburban

Micro

Below close

obstacles

(3-6 m)

0.5-1 km

Urban

Pico

Wall mounted

inside buildings

Up to 100 m

Indoor applications

Height

Radius

Environment


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Electromagnetic Engines for RF PlanningElectromagnetic Engines for RF Planning

Macro cellMacro cellss

Small cellsSmall cells

Micro/pico cellMicro/pico cellss

Terrain profile

Obstacles like knife-edge

Building Percentage

Morphology25-250 m resolution

Diffraction

(Huygens-fresnel)

Ray tracing/launching

Vectorial data base of the building

plan

1-5 m resolution

Diffraction

Reflection

Terrain profile + buildings profile.

Obstacles like knife-edgeBuilding volumetric analysis

5-10 m resolution

Diffraction(Huygens-fresnel)


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Small Cell Environment


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TILAB propagation equation

)log(202.77][][]/[ fdBAdBmPmVdBE TOTTX ++=

d = distance from the source (km)

f = frequency of the radio link (MHz)

heff = effective height of the BTS (m)

Hmob= mobile terminal height (m)

B%

= building percentage (local effect)

[ ] )log()log()log()log()log()log(][

%765

4321

Bkdhkk

hkhkfkkdBA

eff

mobeffTOT

++++=

k1, k2, k3 factors are distinguished on a distance threshold at 8 Km

E = Electrical field (dBV/m)PTX = transmitted power (dBm)

The antenna gain of the MS is assumed to be 0 dBi


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Stretched String Method

1st group of

obstacles

2nd group of

obstacles

3rd group of

obstacles

distance

terrain

height

RBS

MOBILE

Used in macro/small cell models in order to individuate relevant obstacles.


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d

Tx h

Imaginary source

Rx

P

Basic Diffract ion Principle (Huyghens-Fresnel)

The effect of diffraction is taken into account by adding an extra

attenuation to the propagation equation


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Microcellular Environment

MobMob

BSBS

In a microcellular environment the effect of reflections cannot be neglected

Ray tracing/launching techniques are needed


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Coverage calculat ion examples (1)

Dense urban environment

1) Macro cell (h = 50m)


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2) Small cell (h = 30m)


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2) Small cell (h = 30m)

3) Micro cell (h = 6m)


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Best Server Map


Building


Interference Table


Building


Frequency Plan


Definition

Adjacences




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Cell C7 Field E7 E7>Emin

Cell C3 Field E3 < E7 E3 >Emin

Cell C2 Field E2 < E3 E2 >Emin

Cell C9 Field E9 < E2 E9 >Emin..

....

Best ServerMap: the best cell

takes the pixel (if the field is greater than Emin)

Definitions

Ei Field Strength belonging to the cell iEmin Minimum Field Strength for Terminal Access

Definitions

Ei Field Strength belonging to the cell iEmin Minimum Field Strength for Terminal Access

Best Server Maps Calculat ion

For each pixel the field levels of the

different cells are considered:


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Best Server Maps Analysis

With the Best Server Maps evaluationstep we can have the first look of the

set of cells included in the Planning

Process.

After this step each pixel on the

geographic area is exclusively assigned

to a cell.

Each pixel on the geographic area is

exclusively assigned to the cell with the strongest Field strength

among the field levels belonging to the other cells which satisfies

the system constraints (minimum field strength and the timing

advance limit)

Sometimes masks are used to define geographic areas that are not

relevant for the planning (e.g. the sea)


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LDL

E(x,y)

PBTS

Lfeeder

Antenna parameters:- Gain- Azimuth, Electrical/Mechanical tilt- H/V plane diagrams

Coverage levels

)log(202.77minmin

min

fCE

MSC DLMS

++=+=

Different margins (indoor, incar..) lead

to different field level requirements


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Best Server Field Map

For each pixel the electromagnetic field associated to the best serveris

shown (i.e. the best field)

Best server Field Map gives an estimation of the overall network

coverage


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Best Server Field Reference Levels

No margin Outdoor Incar Indoor

Total Margin [dB] 0 19 27 32

Minimum power [dBm] -102 -83 -75 -70

Minimum Field [dBuV/m] 34 53 61 66

Color

)log(202.77 fCELPC DLBTS ++==

Reference field levels (colors) are defined using the same approach ofthe link budget

Best Server Field (received power) is calculated using EM engines:

)log(202.77minminmin fCEMSC DLMS ++=+=

Reference evels are calculated from MS sensitivity, introducing

design margins :


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Netw ork Coverage Analysis

No margin Outdoor Incar Indoor Total Margin [dB] 0 19 27 32

Minimum power [dBm] -102 -83 -75 -70

Minimum Field [dBuV/m] 34 53 61 66

Color

Area with

indoor and

outdoor

coverage

problems

Coverage

borderAreas with

indoor

coverage

problems


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Dimensioning/planning results comparison

Radio Network

Dimensioning (RLB)

Estimated number of sites (N)

Target area

Coverage

evaluation (RLB)

Simulation of N sites

in the target area

(planning tool)

In the radio network dimensioning phase a

regular layout is assumed.

The more irregular is the real network

(morphology, orography, traffic, siteconstraints), the higher is the number of

coverage holes expected in the planning phase.

Each hole must be evaluated in detail.

Possible choices :1) Accept a lower coverage probability in

the critical zone

2) Optimize site positioning and

radioelectric parameters

3) Introduce extra sites, improving also

the capacity in the area. Microcells can

be considered if the critical area is

small.


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Best Server Map


Building


Interference Table


Building


Frequency Plan


Definition

Adjacences




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I .M. Building (1)

),(),(),(/yxEyxEyxIC

B

AAB =

In each pixel (x,y) of the best server area ofcell A, the C/I ratio is evaluated, for

interfering cell B, as: Cell A

EA

Cell B

EB


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I .M. Building (2)

0

5

10

15

20

1 3 5 7 9 11 13 15 17 19 21 23

N

umberofpixel

0

0.2

0.4

0.6

0.8

1

0 5 10 15 20 25

CD

F

Cell ACell B

MA,B is calculated as the 90th

percentile of the ratio EA/EB

%90Pr , =

> BA

B

A ME

E

0.9

MA,B

MA,B

EA/EB [dB]

EA/EB [dB]

90 %


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Interference Table (I.M.)

The Interference Table give us description of the interference between twocells included in the geographic area involved in the Planning Process, in

case ofco-channel assignment

Based on C/I computation on the pixels belonging to interfered cell (C)

B AF

E

D

H I

CG

MC,BMC,B

D

C

B

A

E

A B C D E

The lower the MC,B the greater the interference of cell B on the best server

of cell C in case of co-channel assignment


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Weighted interference table

0

5

10

1520

25

30

35

40

45

1 3 5 7 9 11

13

15

17

19

21

23

Ei/E dB

We

igth

0

0.2

0.4

0.6

0.8

1

0 5 10 15 20 25

Ei/Ej [dB]

CD

The contribution of each

pixel is multplied by a

weigth (e.g. related to

expected traffic)

0.9

MA,B

90 %

Traffic

probability

layer


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Best Server Map


Building


Interference Table


Building


Frequency Plan


Definition

Adjacences



NBR tNBR t


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NBR setsNBR sets

NetworkNBR

Computed

NBR

NBRSet for the

Frequency

Plan

FictitiousNBR

Drive tests

Handover counters

Cell planner experience

PLANNING TOOLPLANNING TOOL

Cell planner

experience

Network elements

Al ith d t t NBRAl ith d t t NBR


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Algorithms used to compute NBRAlgorithms used to compute NBR

Interference Criteria

Every cell pair (i,j) which has at least

one of the 2 elements in the

interference table (Mij or Mji) lower

than a given threshold are defined to

be NBR

Geometric Criteria

Every cell pair (i,j) which has a

common border length percentage(for i or j) greater than a given

threshold are defined to be NBR

Cell ACell B

Cell A

Cell C


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Best Server Map


Building


Interference Table


Building


Frequency Plan


Definition

Adjacences



T ffi S diTraffic Spreading (1)(1)


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Traffic SpreadingTraffic Spreading (1)(1)

Building

Density Roads

Population

Density

The Offered Traffic estimation is needed forCell Dimensioning in term ofnumber of frequency channel to assign to a given cell.

Traffic data (forecasts or measurements) are often referred to large areas.

Traffic spreading is used to define offered traffic on a pixel by pixel basis.

This is carried out by defining a traffic probability (or distribution) layer,

i.e. a raster layer derived by geographic data.

Traffic probability layer: (x,y)



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=

Areayx

Area

yx

yxTyxt

),(

),(

),(),(

AreaT

Traffic measurements(on cell basis)

Traffic forecasts(on area basis)

),( yx

Traffic probability layer

OfferedOffered traffictraffic

layer t(x,y)layer t(x,y)

Cell dimensioning (voice only)


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Cell dimensioning (voice only)

For a new cell:

- estimate offered traffic for thecell

- calulate number of TRX usingthe Erlang-B model

- review dimensioning ofneighbouring cells

-2

0

2

4

6

8

10

0 10 20 30 40 50 60

Offered Traffic [Erl]

NumberofTRXsneeded

0

2

4

6

8

10

12

BlockingProbability%

For an existiting cell:

- ifblocking probability (reportedby cell counters) is high: consider the activation of a new TRX

- iftime slots occupation (also reported by cell counters) is low: considerthe de-activation of an existing TRX (if more capacity is needed for

others cells in the network)

Target: determine the number of TRX needed for each cell

Traffic spreading (example)


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Traffic spreading (example)

In the existing network, offered traffic can be derived, on a cell basis,

from counters.

For each cell, the traffic can be spreaded over the best server area of the

cell. This leads to a traffic raster layer.

Est imat ing offered traffic for a new site


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Est imat ing offered traffic for a new site

When a new site is added to thenetwork, offered traffic can be

estimated considering the

previous traffic layerand the

fresh traffic contribution)()()(

)()()(

kiTiTiT

kiTkTkT

stolennew

istolenfreshnew

=

+=

GSM/EDGE Planning Process


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Site PositioningSite Positioning


Best Server Map


Building


Interference Table


Building


Frequency Plan


Definition

Adjacences



Frequency Plan (Problem Definit ion)


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Frequency Plan (Problem Definit ion)

A Frequency Plan gives an answer to the question:

Which RF Channels in each Cell?A Frequency Plan gives an answer to the question:

Which RF Channels in each Cell?

Targets Reach a good enough Quality Level in terms of interference criteria and

maximize system performances in terms of C/I

Take account of the whole set of frequency reuse constraints

Optimum Solution

Each carrier in each cell with C/I respecting the quality threshold:

9 dB for GSM

depending on Coding Scheme if GPRS/EDGE is used

Each assigned frequency respect the minimum reuse spacing for:

Cell constraint

Site constraint

Adjacencies constraint

Other project area or operator specific constraint in frequency reuse

Frequency Plan (Problem Complexity)


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Frequency Plan (Problem Complexity)

Computational problem class NP-hard.It is impossible to find the optimum by examinating

exaustively all the possible solutions

Computational problem class NP-hard.It iIt is impossibles impossible toto findfind the optimumthe optimum byby examinatingexaminating

exaustively all the possibleexaustively all the possible solutionssolutions

A Frequency Plan definition assign N carriers for each of the K cells in

the network selected from a set ofM frequencies in the available band

Example300 cells with 2 carriers

50 frequencies availiable

Example

300 cells with 2 carriers

50 frequencies availiable

No of solutions:

12252

50

N

M 300300k =

=

Frequency Plan (Theoretical Situat ion)


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Frequency Plan (Theoretical Situat ion)

radio-electrical features are the same for each cell all cells have the same shape and the same number of carriers the frequency assignment method is based on geometric considerations

radio-electrical features are the same for each cell all cells have the same shape and the same number of carriers the frequency assignment method is based on geometric considerations

It is very simple to use

but it does not take

the real situation

into account!

It is very simple to use

but it does not take

the real situation

into account!

Available frequency band

1 2 3 4 5 6 7

1

1

2

2

3

3

44

5

5

66

7

7

Cluster

Frequency Plan (Real Situation)


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Frequency Plan (Real Situation)

Available frequency band

1 2 3 4 5 6 7

1

12

2 3

3 4

4

5

5 6

7

The radio electrical features foreach cell are different because

altitude and building layers

are considered

The radio electrical features foreach cell are different because

altitude and building layers

are considered

Cells shape and extension

are differentCells shape and extension

are different

The cell equipment has to carry

the offered trafficThe cell equipment has to carry

the offered traffic

Each cell has assigned a

different number of carriersEach cell has assigned a

different number of carriers

Frequency Plan Optimization Tools (1)


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Frequency Plan Optimization Tools (1)

High number of CellsHigh number of Cells

Nature of Reuse

Constraints

Nature of Reuse

Constraints

High number of

possible solutionsHigh number of

possible solutions

High Computational

power needed

High Computational

power needed

Using Software Tools for Frequency Planning

allow to evaluate an high number of possible solutionstaking account of a complex set of interference data

and constraints not easy to manage in traditional ways.

Using Software Tools for Frequency Planning

allow to evaluate an high number of possible solutions

taking account of a complex set of interference data

and constraints not easy to manage in traditional ways.

Frequency Plan Optimisation Tools (2)


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q y p ( )

Interference

TableInterference

Table

Cells EquipmentsCells Equipments

Reuse Constraints

Set (including NBR)Reuse Constraints

Set (including NBR)

Handover and Traffic

measurementsHandover and Traffic

measurements

Interdicted or notusable frequency setInterdicted or not

usable frequency set

Available BandwidthAvailable Bandwidth

Inputs

Optimisation Engine

EURISTIC APPROACH

Cost Function FC

Output

Best solution

(optimum)

FP inputs: available bandw idth


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FP inputs: available bandw idth

f1

f2

f3

f4

f5

f6

f7

f8

f9 .

fN

Limited number

of available channels

Licensed bandwidth

Available bandwidth is defined by the identifying numbers and by thefrequency values of RF channels available for the frequency plan.

The number of channels available for each cell to be planned is furtherlylimited by interdicted frequencies due, for instance, to agreementsbetween operators at the country borders or to blocked sitesat theborder between different FP areas.

Interdicted frequencies

X X

FP inputs: IM and cell equipments


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p q p

Best Server Map


Building


Interference Table


Building


Frequency Plan


Definition

Adjacences



The Interference matrix gives the description of the interferencebetween two cells included in the geographic area involved in the

Planning Process, in case ofco-channel assignment

Cell dimensioning gives the number of needed RF channels foreach cell

FP inputs: reuse constraint set (1)


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FAFB

FF

FG

FC

FD

Site

Adjacency

Cell constraint: Minimum spacing between channels

assigned to the same cell: Nc

Nc = 3 600 kHz in GSM 900 MHzNc = 5 1000 kHz in GSM 1800 MHz

Site constraint: Minimum spacing between channels

assigned to cell belonging to the same site: NsNs = 2 400 kHz in GSM 900/1800 MHz

Adjacency constraint: Minimum spacing betweenchannels assigned to neighbouring cells: NA

NA = 1 200 kHz in GSM 900 MHzNA = 2 400 kHz in GSM 1800 MHz

p ( )

Reuse constraints affect the frequency assigment for each cell:

FP inputs: reuse constraint set (2)


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Cell and site constraints are due to technological limits of the

BTS apparates

Handover procedure requires the origin cell and destination cell notdo be assigned with common channels

Interference: when two cells (A,B) interefere to each other but the IMcoefficients (MAB and MBA) are high (e.g. because of simulation or

geographic data inaccuracies), it is possible to define a NBR in order

to avoid a co-channel assignment

Adjacency constaints are used for two different reasons:

FA,FB,FC

FD,FE

Cost funct ion


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COSTFUNCTION

COSTFUNCTION

Interference part

Reuse constraint part

Number of carriers under threshold

Minimum C/I of the FP

Average C/I of the FP

Cell constraints violationsSite constraints violations

Adj 200 kHz constraints violations

Adj 400 kHz constraints violations

Each solution (i.e. each alternative FP) generated by the optimizationengine is evaluated using a multi-dimesnional cost funcion taking

different parameters into account

vncC

intCC FFF +=

Cost funct ion (weights)


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Minimum C/Iof the FP

Average C/Iof the FP

Adj. 200 kHz constraints

violations

Site constraints

violations

Cell constraintsviolations

Number of carriersunder threshold

Interference Part Reuse constraints part

Weigths

vncC

intCC FFF +=

The importance of each term in the cost funcion is determined by a weigth

Adj. 400 kHz constraints

violations

Optimizat ion tool behaviour


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Move Type A

1 frequency

substitutionin 1 cell

Move Type A

1 frequency


2 Frequency Plans

are differentfor 1 assigment

Type A

Move Type B

1 frequency


Move Type B

1 frequency


2 Frequency Plans

are differentfor 2 assigment

Type B

Initial FP FP 2 FP 3 FP 4 FP 5 Final FP t

Fc

Each solution is generated by moves

Optimizat ion tool outputs


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For each Cell

List of assigned RF Channels

Channel Quality (Statistical C/I)

List of violated Reuse Constraints

Frequency Reuse Distribution

Global FP Quality Data

CO08D1 34 16 20 30 43 -1 -1 -1 -1

CO70D1 40 31 -1 -1 -1 -1 -1 -1 -1MI01D1 19 37 47 63 16 -1 -1 -1 -1

MI01D2 57 35 53 50 31 -1 -1 -1 -1

MI01D3 40 59 27 33 43 21 55 12 -1

MI02D1 66 21 33 59 -1 -1 -1 -1 -1

MI02D2 36 63 28 43 19 46 -1 -1 -1

CELL F1 CELL F2 Constr

MI11D1 24 MI11D2 25 SITE

MI11D1 24 MX78D2 24 ADJ 200



MI11D2 40 MY65D1 40 ADJ 200



MI11D3 29 MI11D3 28 CELL200

Best solution characteristics:

BCCH Frequency planning


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minimum number of reuse constraints violations

maximum C/I (used when two carriers assigned to the cellhave the same number of reuse constraints violations)

BCCH carrierof each cell can be chosen among the assigned

frequency channels (after FP). Two possible criteria:

An alternative solution is BCCH carriers segregation

(Two different FP are defined for BCCH carriers and for TCHcarriers)

BCCH Segregat ionBCCH Segregat ion (1)(1)


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Available Band

Sub-Band A

Configuration 1

Sub-Band B

Sub-Band A Sub-Band B

Configuration 2

Sub-Band BSub-Band A

Sub-Band A & B

Configuration 3

BCCH Segregat ionBCCH Segregat ion (2)(2)


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Main advantage: BCCH quality improvement in terms of C/I (mostly on non-fully

mature networks) and better control on potential interfering

sources

Main drawbacks:

The benefits of segregation decrease in high re-useenvironments.

Impacts on re-use constraints: sub-bands represent an extraconstraint in the frequency assignment process. This leads to

a higher constraints violation probability, particularly in mature

networks

It is seldom applicable in mature networks, unless a large

bandwidth is available.

Frequency planning advanced features


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The following nework features can be introcuced to reduceinterference and to provide a better frequency reuse:

DTX: downlink discontinuous transmission downlink consists in

switching off the BTS transmitter during pauses in speech or datatransmission.

Base Station Power Control: the output power of a Base TransceiverStation (BTS) can be controlled during a connection in order to

maintain a desired received signal strength and quality in the mobilestation (MS).

Frequency Hopping: consists in changing the transmitting frequency

(among the carriers assigned to the cell) for the voice/data burststhat have to be sent on the radio interface.

The expected gain provided by these features can be considered

during the assignment procedure

GSM/EDGE Planning Process


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Site PositioningSite Positioning


Best Server Map


Building


Interference Table


Building


Frequency Plan


Definition

Adjacences



Frequency plan quality analysis (1)


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The Quality Analysis of the defined Frequency Plan is performed via a C/Iper pixel computation (for each cell, for each carrier)

BTS(2): FA, FD

42

1

EE

E

I

C

AF

+=

BTS(1): FA, FB, FC

BTS(3): FE, FG

BTS(4): FA, FB

BTS(5): FD, FL, FH



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BCCH C/I Best C/I

Worst C/I AverageC/I



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Single carrier C/I and reuse analysis: examples

Carrier No. 8 Carrier No. 9



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Impact of dominant sites

on frequency reuse:

Frequencies assigned to

the dominant site (e.g. 40)cannot be reused in the

high traffic area

F1

Reuse analysis: carrier No. 40

Quality optimization example (1)


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Quality (C/I) can be locally improved by manually re-assign frequecies forselected cells in the network (paying attention also to reuse constraints)

Example: analysis ofcritical area forBCCH C/I

Quality optimization example (2)


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BCCH frequency is re-

assigned (54 33)BCCH quality in the

area is improved.

Manual optimization

can be assisted by theplanning tool

Serving cell in the critical area is individuated.


Site Positioning


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gSite Positioning


Best Server Map


Building


Interference Table


Building


Frequency Plan


Definition

Adjacences



EDGEEDGE

EDGEEDGE

Traffic spreading w ith data services


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With E-GPRS (or simply GPRS) introduction, GSM becomes a multi-service network. Each service has its own coverage and quality

requirements (e.g. defined in terms ofE orC/I thresholds)

Each service has a different traffic probability layer and, as aconsequence, a different traffic layer.

For circuit switched (CS) services: Erl

For packed switched (PS) services: Mbyte/h or ErlEq

Specific measurements/forecasts have to be carried out for eachservice (e.g. data and voice statistics)

Cell dimensioning (voice+data)

Dimensioning models have to evolve in order to consider traffic of data


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Dimensioning models have to evolve in order to consider traffic of dataservices (showing typically a variable bit rate)

When multi-service traffic is considered, the impact of RRM (RadioResource Management) on cell dimensioning must be considered (RRM

algorithms are vendor-dependent!)

Traffic and

RRM modelsOffered voice

(Erl) and data

(Mbyte) traffic

Number of GSM and

GSM/EDGE carriersRRM parametrs

Performace indicators:

-blocking prob. (voice)

- avg. throughput (data)

Adjust cell equipments

until target performance

is met

Dimensioning example (GIANUS Model)

Dimensioning of a GSM/GPRS/EDGE cell with full and half rate carried

EXTRA


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traffic and GPRS/EDGE offered traffic

Voice offered traffic: 30 Erlang

GPRS CS2: 10.5 kbps EDGE MCS6: 29.6 kbps

UL/DL GPRS Mbytes offered: 10/20 UL/DL EDGE Mbytes offered: 5/10

Dual Rate terminals percentage: 90% # of sign time slots: setting table

Number of dedicated time slots: 2 # of EDGE time slots: 4

DR Resources Activation Thr. : 70% Terminal Capability: 4+1

Ericsson: TBFULLIMIT,TBFDLLIMIT: 1

Required voice loss: 2% Required data loss: 1%

UL/DL required GPRS thr. : 10/20 kbps

UL/DL required EDGE thr. : 20/60 kbpsNumber of carriers: 4 Voice Loss: 0.11%

Number of traffic time slots: 30 UL/DL Data loss (%): 0.01,0.33%UL GPRS throughput: 10.33 kbps DL GPRS throughput: 25.06 kbps

DL EDGE throughput: 28.20 kbps DL EDGE throughput: 52.30 kbps

Frequency planning w ith EDGE


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Relevant input information:

Number of EDGE TRX per cell

EDGE on BCCH TRX? (depends on the impact of APD)

Possible approachs to FP:

Free band FP without specific weights for EDGE TRXs:EDGE Carriers may be chosen among cell ARFCNs after

FP (e.d.g. on the basis of maximum C/I criteria)

Band segregation for EDGE

Free band FP with specific weights for EDGE TRXs:

optimization is used in order to drive better quality onEDGE carriers (a degradation of average C/I for voice only

carriers is expected)

Frequency planning w ith EDGE (example)Case study: 2333 cells with a total of 8736 carriers. About 5% of blocked


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y

cells. Available bandwidth: 56 ARFCNs. EDGE on BCCH carrier

FP A: Free band planning (without specific weights)

FP B: Segregation (12 carriers dedicated to BCCH/EDGE)

FP C: Segregation (24 carriers dedicated to BCCH/EDGE)

FP D: Free band with specific weights for BCCH/EDGE carriers

Parameter FP A FP B FP C FP DC/I min BCCH/EDGE [dB] 8.58 5.27 9.91 11.92

C/I min TCH [dB] 7.06 5.25 0.81 5.81

C/I med BCCH/EDGE [dB] 18.61 14.74 21.07 21.81

C/I med TCH [dB] 15.39 16.32 12.85 13.23

BCCH/EDGE under threshold 2 61 0 0

TCH under threshold 39 23 514 267

Constraints violations (TCH only) 165 6 515 165

avg

avg

Band Segregation for EDGE


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Pros: Good radio conditions and guaranteed available resources

for EDGE.

Cons:

GSM voice quality could be affected Based on the expected demand growth in the future,

extending EDGE on other carriers beyond the first reserved

ones could be not easy

If it is not possible to find out EDGE suitable carriers (in termsof C/I) for all the cells, it could be advisable to use band

segregation to plan GSM and EDGE separately

EDGE on BCCH TRXEDGE on BCCH TRX (1)(1)


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8-PSK modulated TSs on the BCCH carrier, with the exceptionof TN7, may use a mean power which is at most 4 dB lower thanthe power used for GMSK modulated TSs.

If the Operator decides to allow 8-PSK modulation on the BCCHcarrier in certain cells, the cell re-selection and handoverprocedures involving these cells will be somewhat sub-optimal.

The extent of the performance degradation is dependent upon:

the measurement schedule in each particular MS

the used Average Power Decrease (APD)

the current 8-PSK load

the signal fluctuations resulting from8-PSK modulation

Additionally, in areas with very low cells overlap, some coverageloss effects may have to be taken into account by the Operator.

EDGE on BCCH TRX (2)


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Alternative 1:Alternative 1:Reducing the power of the GMSK modulated TS

to the 8-PSK modulated TS level

Pros:the BCCH carrier power is constant, not affecting themeasurement reports with signal fluctuations, apart fromthose resulting fromthe 8-PSK modulation characteristics

Cons:it causes a reduction of the coverage area of the cell

EDGE on BCCH TRX (3)


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Pros:the BCCH power is not reduced

Cons:cell re-selection and handover procedures will be sub-

optimal

Alternative 2:Alternative 2:Introducing the Average Power Decrease of the 8-PSK

modulated TSs with respect to the GMSK modulated TSs level

TXTX PowerPowerGMSK

8-PSK

TTNN00 GMSKGMSKGMSKGMSK GMSKGMSK GMSKGMSK88--PSKPSK 88--PSKPSK 88--PSKPSK

APD

tt


Site Positioning

EXTRA


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Best Server Map


Building


Interference Table


Building


Frequency Plan


Definition

Adjacences



HCSHCS

HCSHCS

HCSHCS

HCSHCS

Hierarchic structures

V i Di i i

EXTRA


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Voice Dimensioning:

Micro 900 MHzMicro 900 MHz

Macro 900Macro 900

MHzMHz

Macro 1800 MHzMacro 1800 MHz

Hierarchical Cell Structure

Traffic Overflow(Fredericks-Wilkinson) Micro 900Micro 900

Macro 1800Macro 1800

Macro 900Macro 900

System Loss

Total Offered Traffic

Traffic Overflow

Traffic Overflow

Targets and Constraints:

System Loss (%) --> 2 % Max TRX per Cell --> 8

First Server Definit ion

EXTRA


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Best Server

for

not Hierarchical

Networks

Best Server

for

not Hierarchical

Networks

Each pixel in the geographic area is exclusively assigned to

the cell with the strongest Field strength,

chosen among the cells which satisfythe system constraints

(minimum field strength and the timing advance limit)



chosen among the cells which satisfythe system constraints

(minimum field strength and the timing advance limit)

First Server

for

Hierarchical

Networks

First Server

for

Hierarchical

Networks



chosen among the cells which satisfy

the system constraints

(minimum field strength and the timing advance limit)taking the Hierarchical Cell Structure in account



chosen among the cells which satisfy

the system constraints

(minimum field strength and the timing advance limit)taking the Hierarchical Cell Structure in account

First Server Calculat ionFirst Server Calculat ion

E

E

XTRA


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Cell C3 Field E3 < E7 E3 >Smin

Cell C2 Field E2 < E3 E2 >Smin

Cell C9 Field E9 < E2 E9 >Smin..

..

..

Best ServerMap

the best cell

takes the pixel

Cell C4 (L1) Field E4 E4>Smin, S1

Cell C2 (L1) Field E2 < E4 E2>Smin, S1

Cell C8 (L2) Field E8 > E4, E2 E8>Smin, S2

Cell C5 (L2) Field E5 < E8 E5 >Smin, S2..

..

..

First ServerMap

the best cell takes the pixel

according to Hierarchical algorithm

Ei Field Strength belonging to the cell iSmin Minimum Field Strength for Terminal AccessLj Hierarchical Level j[1,5]Sj Hierarchical Threshold of Level j

Ei Field Strength belonging to the cell iSmin Minimum Field Strength for Terminal AccessLj Hierarchical Level j[1,5]Sj Hierarchical Threshold of Level j

Definitions:

First Server Example

E

XTRA


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900 only BTS

1800/900 BTS

1800 coverage

(with HCS)

900 coverage

Tow ards a hierachica l multi-access netw ork

A multi access network (GSM//EDGE/UMTS) can be considered as


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A multi access network (GSM//EDGE/UMTS) can be considered asa hierarchical cell structure

Service: e.g voicecalls on GSM layer,

videocalls on UMTS

layers, sharing ofdata calls

RRM algorithms determine the best layer for each user, considering :

GSM/EDGE GSM/EDGE GSM/EDGE GSM/EDGE

UMTSMacro F1

UMTSMacro F1

UMTSMacro F1

UMTSMicro F2

Soft HO

Soft HO

Hard HO

Inter-System HO


UMTSMacro F1

UMTSMacro F1

UMTSMacro F1

UMTSMicro F2


UMTSMacro F1

UMTSMacro F1

UMTSMacro F1

UMTSMicro F2

Soft HOSoft HO

Soft HOSoft HO

Hard HO

Inter-System HO

Mobility: e.g. Fast moving users on macro layers (GSM and UMTS), slowmoving users on micro layers (GSM and UMTS),

Quality: e.g quality based inter-system handover in critical areas

Load: different policies are feasible (overfolw. load balancing)

A first example: intersystem HO planning

GSM Handover


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UMTS

CPICH

Ec/Io

GSMBCCH

C/I

HandoverGSM to

UMTS

Handover

UMTS to

GSM

Bibliography


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3GPP TS 05.05, Technical Specification GroupGSM/EDGE, Radio Access Network; Radio

transmission and reception (Release 1999)

ETSI TR 101.362, Digital cellular telecommunicationssystem (Phase 2+); Radio network planning aspects

(GSM 03.30 version 8.3.0 Release 1999)

GSM, GPRS and EDGE Performance, Edited by T.Halonen, J. Romero and J. Melero, Wiley


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Thank you for the at tent ion!

[email protected]

PlanningGSM Rio Part2 New

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