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1

Radio network planningRadio network planning

andand engineringenginering

Sami TabbaneSami Tabbane

Damascus - Syria, 27-29 July 2009

ITU/BDT Arab Regional Workshop on

“ ICT Applications for Rural Communications”

2

CellularCellular

networksnetworksfundamentalsfundamentals



2

3

Cellular network fundamentalsCellular network fundamentals

• Main issue: How accommodate the maximum number of

mobile subscribers with a limited resource of bad quality

and out of control?

4

44 propagation basic phenomenaspropagation basic phenomenas

Réflexion Réfraction

Diffraction

DiffusionScattering

ReflectionRefraction

Diffraction



3

5

3D Rayleigh environment3D Rayleigh environment

6

Cellular architectureCellular architecture

• Frequency reuse:

- More capacity,

- More coverage.

.. < > ^ ... . . .

.. < > ^ ... . . .

.. < > ^ ... . . .

. . .

C I

1

I 2 I 3

f 1

f 1

f 1

f 1

.. < > ^ ... . . .



4

7

EngineeringEngineering

• Problem:

How to design /tune/optimise the network to:

1. Vehiculate the maximummaximum volume of

traffic,

2. To fullfil the QoS contraintes,3. While minimisingminimising the investments ?

8

Multiple access methodsMultiple access methods

• FDMA and TDMA: Concentration of the interference on

some channels.

• CDMA: interference is

spread over all the channels.

Fréquences

Temps

Codes/Puissance

f

t

f1

.

.

.

fi

f

t

f1

.

.

.

fj

1 2 3 4 5 6 1 2 3 4 5 Trame TDMA

Intervalle de temps ou time slot Time slot

Power/Code

Time slot

Time

Frequencies



5

9

Cellular systemsCellular systemsspecificitiesspecificities

• Subscribers mobility

management,

• Radio interface management.

10

Mobility managementMobility management

Active mobile (dedicated mode):

Handover

Inactive mobile (idle mode): twoprocesses

Cells selection/re-selection

Location management (roaming).



7

13

Frequency reuse (1)Frequency reuse (1) Definition: frequency reuse is the use of the same

radio channels to cover different areas separatedfrom each-others by distances high enough sothat the co-channel interference is not too high.

Mobile

Site C

Site B Site A

.. < > ^ ... . . .

C

I I’

f 1

f 1

f 1

14

Frequency reuseFrequency reuse (2)(2)

Channel

15

Channel

6

Channel

15

SNmin = 9 dB



8

15

ClusterCluster

1st case: R = 10 km with N = 7 frequencies. 7 simultaneous communications.

2nd case: r = 5 0 0 m

(R/r)2 = 400 therefore 400.1 = 400 simultaneouscommunications.

∆ f5

f1

∆ f2

∆f3∆ f7

∆ f4

Zone A Zone A

R

r

F∆

∆

∆ f6

F =∆ ∆ f1 +∆ f2 +∆ f3 +∆ f4 +∆ f5 + f6 + f7

Cluster

∆ ∆

16

Number of cells per cluster (1)Number of cells per cluster (1) Given a cluster of hexagonal shape.

N : cells number per cluster,

a ( A): cell area (whole cluster),

R: hexagon side.

Distance between two co-cells = D, Radius (side)of the cluster (supposed hexagonal) =(D/2)/cos(π /6) = D/

233

2 Ra =

3

A

D D

= =

°

3 31

23

2

22

230cos



9

17

Number of cells per clusterNumber of cells per cluster (2)(2)

Thus and: ,a

A N = N D

R=

2

23.

D

R N = 3

C1

(2)C

1

(3)

C1(1)

C1

(6)

C1

(5)

C1

(4) C 1

Cluster

Pôle

Cellule

18

Example: 4/12 and 3/9 size clustersExample: 4/12 and 3/9 size clusters

9 cells cluster: 3 BTSs with 3 sectors per BTS,

12 cells cluster: 4 BTSs with 3 sectors per BTS,

D1

D2D

3

A1

A2A

3

B1

B2B

3

C1

C2C3

A1

A2

A3

B1

B2B

3

C1

C2C

3

Motif 4/12

Motif 3/9



10

19

Reuse Partitioning Reuse Partitioning

12

34

1' 2'

3'4'

1' 2'

3'4'

1' 2'

3'4'

1' 2'

3'4'

1'

3'

4

5 41 2

1 2

3

7

6

6

6

57

57

3

3

1, 2, 3, 4, 5, 6, 7 : Cellules du motif à 7 (1)

1', 2', 3', 4' : Cellules du motif à 4 (2)

20

Reuse cluster: TDMA/FDMA andReuse cluster: TDMA/FDMA and

CDMACDMA

frequencyfrequencyfrequencyfrequency

TDMATDMA DSDS--CDMACDMA



11

21

CDMA reuse cluster: multipleCDMA reuse cluster: multiple

access interferenceaccess interference

TDMATDMA DSDS--CDMACDMA

Downlink Downlink

22

D/R and C/I relationshipD/R and C/I relationship

q = D/R: co-channel reuse ratio.

High q low potential interference level.

q co-channel interference .

D: function of K I

(nbr of co-channel cells in the

first ring) and of C/I .

with C proportional to R-γ and

I proportional to D-γ .

C

I

C

k k

I I K

=

=

∑1

( )

C

I

R

Dk k k

I K

k q I K

= =

−

−

=

−

=

∑ ∑

γ

γ γ

1 1

1



12

23

The cellThe cell

Geographic area which limits aredetermined by:

1. The transmitted power and the receiverssensibility,

2. C/I ratio fixed by the system,

3. Capacity to managed the maximumnumber of communications on theallocated are with the required QoS,

4. Integration of the cell in its environment

24

Relations between cellsRelations between cells

Service area

Cross-coverage

Co-channel interference



13

25

1. UMTS main1. UMTS main

proceduresprocedures

UMTS Radio Functionalities (1)UMTS Radio Functionalities (1)

The UE scans all RF channels in

WCDMA and searches for the

strongest cell signal on each

carrier.

The UE displays those PLMNs

that are allowed as well as those

that are not allowed based on the

strongest signal cell on each

frequency.

The user can select a PLMN

manually from the list

2. Manual mode

3.

1.

f1

f2

•

•

fn

Strongest cell

0 .2 0 .4 0 .6 0 .8 1 1 .2 1 .4 1 .6 1 .8x107

-40

-20

0

20

40

60

80

Frequency

P o w e r S p e c t r u m M a g n i t u d e ( d B )

PLMN APLMN BPLMN DPLMN E

2.

Idle mode: PLMN selection

26



14

Initiate Cell Synchronization

P-CCPCH

(PSC + SSC + BCH)

UE monitors Primary SCH code, detects peak in matched filter output

Slot Synchronization Determined ------>

UE monitors Secondary SCH code, detects SCG and frame start time offset

Frame Synchronization and Code Group Determined ------>

UE determines Scrambling Code by correlating all possible codes in group

Scrambling Code Determined ------>

UE monitors and decodes BCH data

BCH data, Super-frame synchronization determined ------>

UE adjusts transmit timing to match timing of BS + 1.5 Chips

Cell Synchronization complete

Idle mode: search process

Idle mode behavior: Cell search procedure27


Squal = Qqualmeas- qQualMin > 0

Srxlev = Qrxlevmeas – qRxLevMin – Pcompensation > 0

Where Pcompensation = max(maxTxPowerul – P;0)

qQualmin: sent in the broadcast information and indicates the

minimum required quality value. The UE measures the received

quality, “Qqualmeas”; on the CPICH (CPICH Ec/N0) and

calculates Squal.

qRxLevMin: sent in the system information and indicates the

minimum required signal strength. The UE measures the received

signal Code Power (CPICH RSCP) and obtains Srxlev

Cell selection process

28




15

• Qqualmeas

• Qrxlevmeas P-CCPCH

CPICH

• qQualmin

• qRxLevMin

• maxPowerul

maxTxPowerful: the maximum transmission power during

random access on the RACH. Value sent in the system

information.

P: the UE maximum output power according to its class

Cell selection process

Idle mode behavior: Cell selection process 29


S q u a l > 0 ( on l y W C D M A c e lls )

S rx le v > 0

In order to always camp on the best cell the UE performs the cell

reselection procedure in the following cases:

When the cell on which it is camping is no longer suitable.

When the UE, in “camped normally” state, has found a better

neighboring cell than the cell on which it is camping.

When the UE is in limited service state on an acceptable cell.

When the UE triggers a cell reselection evaluation process, it

performs ranking of cells that fulfill the following criteria:

Cell reselection process

30




16

Cells are ranked according to the R criteria:

R(serving) =Qmeas(s) + qHyst(s)

R(neighbor) = Qmeas(n) - qoffset(s,n)

Qmeas is the quality value of the received signal.

Qmeas may be derived from the averaged CPICH Ec/No or

CPICH RSCP for WCDMA cells.

Qmeas uses the averaged received signal level for GSM cells.

CPICH RSCP is always used as a measurement quantity when

WCDMA cells are compared with GSM cells. 31



Qmeas(n)

Qmeas(s)

qoffset(s)

qHyst(s)

R(s)

R(n)

treSelection

Cell reselection

time

Quality

Idle mode behavior: Cell reselection procedure

32





17

Cell reselection criteria are used for intra-frequency, inter-frequency

and inter-RAT cells.

Decision on when measurements on intra-frequencies should be

performed is made using the parameter sIntraSearch in relation to

Squal.

If Squal > sIntraSearch the UE does not need to perform

intrafrequency measurements.

If Squal ≤ sIntraSearch the UE performs intrafrequencymeasurements.

If the sIntraSearch is not sent to the serving cell, the UEperforms intrafrequency measurements.

33



The decision on when measurements on GSM frequencies should

be performed is made using the parameter sRATSearch.

If Squal > sRATSearch the UE does not need to performmeasurements on GSM cells.

If Squal ≤ sRATSearch the UE performs measurements onGSM cells.

If sRATSearch is not sent for the serving cell, the UE performsmeasurements on GSM cells.

34





18

The UE is also supposed to be able to measure on inter-

frequency cells. The decision on when measurements on inter-

frequencies should be performed is made using the parameter

sInterSearch in relation to Squal.

If Squal > sInterSearch the UE does not need to perform

interfrequency measurements.

If Squal ≤ sInterSearch the UE performs interfrequencymeasurements.

If the sInterSearch is not sent for the serving cell, the UE

performs interfrequency measurements.

35



Frame withPI Indicator

Associated

S-CCPCH frame• • •

• • • • • •

• • •

PICH

S-CCPCH

τPICH= 2ms = 3 TS

When the UE is in Idle mode, two different physical channels are

used in order to deliver proper information from the WCDMA

RAN to the UE: the PICH and the S-CCPCH (carries the PCH).

The PICH is used to indicate to the UE when it should read the S-

CCPCH and the PCH is used to carry the RRC message “pagingtype 1”, which contains the actual paging information

Idle mode: Paging

36




19

MasterInformation

Block

SystemInformation

Block 1

SystemInformation

Block 2

SystemInformation

Block 3

The System Information elements are broadcast in System

Information Blocks (SIBs). A SIB groups together System

Information elements related to the same kind of activity controls.

Different types of SIB exist, and each type contains a specific

collection of information.

A Master Information Block (MIB) gives reference to a number of

SIBs.

Idle mode behavior: system information grouping

System information

37


x

SIB12

x

x

SIB11

x

MIB

x

x

x

SIB1

x

SIB3

x

SIB5

Location and routingupdating

xPower Control oncommon channel

Timers and counters inIdle mode

Cell and commonchannel configuration

Measurementmanagement

Paging parameters

Cell selection andreselection parameters

PLMN Identity

SIB7Contents

Idle mode behavior: system information details 38

System information




20

39

RRM algorithms implementationRRM algorithms implementation

- Power control

- Quality measurements

- Measurement report

- Packet scheduling

- Load control

- Fast power control

- Rate adaptation

- H-ARQ, MIMO

- Admission control

- Load control- HO control

- Outer loop power

control

UEUE Node BNode B RNCRNC

4 types of HO:

Soft handover : between 2 (or more) cells in two

different sites

Softer handover : between 2 cells belonging to same site

Inter-frequency handover : between 2 WCDMA

frequencies

IRAT handover : GSM UMTS or UMTS GSM

40

Handover




21

SRNC CNGood block

Block in error

Decrease BLER = Increase the end user perceived throughput:

Rp = (1-BLER)*R

41

Soft Handover


RBS

Sector 2

Sector 1

Handover: softer handover

42

Softer Handover




22

Content Description

Measurement type Intra-frequency, inter-frequency or IRAT HO

Measurement Identity number To reference measurement reports in UL

Measurement command Setup, modify or release

Measurement objects Measured cells (GSM + UMTS)

Measurement quantity CPICH RSCP or Ec/N0

Measurement reporting criteriaThe triggering for measurement report (event

1a ….)

Measurement reporting mode Use acknowledge or unacknowledged mode

43

Softer Handover process


From the UE point of view, the WCDMA cells are divided into Active,

Monitored , and Detected Sets.

i. The Active Set : The radio links involved in the handover

ii. The Monitored Set : The neighbors of the Active Set cells, areexplicitly measured for handover (can contain both intra-frequency

and GSM neighboring cells).

iii. The Detected Set : The UE is also required to detect intra-frequency

cells that are not in the Active or Monitored Sets

The active set size is configured by operator using

“maxActiveSet” parameter (from 2 4 cells) 44





23

reportingRange1a

Measurement

quantity

time

P_CPICH best cell

Reportingevent 1b

reportingRange1b

Reportingevent 1a

P_CPICH 2

Soft HO procedure: Add / remove of radio link45



hysteresis1c/2

Measurementquantity

time

P_CPICH 1

Reportingevent 1c

P_CPICH 2

P_CPICH 3

P_CPICH 4

Soft HO procedure: replace of radio link 46





24

hysteresis1d/2

Measurement

quantity

time

P_CPICH 1

Reportingevent 1d

P_CPICH 2

P_CPICH 3

Soft HO procedure: change of the best cell 47



MeasurementQuantity

(Ec/No and RSSI)

UMTS Cell

GSM Cell

usedFreqTresh2f

usedFreqTresh2dhysteresis2d/2

hysteresis2f/2

hysteresis2d/2

utranTresh3a

gsmTresh3ahysteresis3a/2

hysteresis3a/2

Reporting

event 2d

Reporting

event 2dReporting

event 2f

Reporting

event 3a

Start measurement on

GSM cells

Stop measurement on

GSM cells

Perform HO to GSM

cell

IRAT handover: thresholds and hysteresis 48

IRAT Handover




25

1…………1

5

1 2 3 4 12 13 1………..1514 15Gap of 7 slots

Normal frame (SF =16) Normal frame (SF=16)Compressed frame (SF = 8)

UE performs measurement on other frequencies

(IF or IRAT handover) RBS Total

power

RNC CPU

load

38 dbm 41 dbm 38 dbm

60 % 65 % 60 %

Lost codes = 16 codes of SF = 256

IRAT handover: compressed mode algorithm

49

Compressed mode


UE RBS RNC MSC BSS

Measurement report

Compressed mode control

Measurement control

Measurement report

Evaluation of MR

Evaluation of MRRelocation required

Relocation command

GSM: HO request

GSM: HO ack Handover from UTRAN command

GSM: HO access + HO complete

GSM: HO completeIu connection release

RRC release

50

IRAT Handover process




26

IRAT HO: from WCDMA to GSM (CS mode)

IRAT CC : IRAT Cell Change is from WCDMA to GPRS (PS mode)

The only difference is that in IRAT HO, the RRC connection remains

between UE and WCDMA RAN (also Iu connection) until receiving

a successful HO message from BSS (to RNC)

In case of a HO failure (WCDMA GSM) UE may return to

WCDMA system.

However, in IRATCC, the Iu connection (also RRC) would be

released since the send of “Cell change order message “ from SRNC

(include GSM cell details)

UE will not be ever connected to WCDMA system51

IRAT HO Cell Change


UE RBS RNC MSC BSS

Measurement report

Compressed mode control

Measurement control

Measurement report

Evaluation of MR

Evaluation of MR

Cell change order from WCDMA RAN

GSM RA update

RRC release

Stop DL transmissionIu release command

Iu release complete

52

IRAT Handover process




27

Algorithm for IRATCC to WCDMA controlled by the network via

parameters FDDQMIN and FDDQOFF

MeasurementQuantity

FDDQMIN

FDDQOFF

CPICH Ec/No

GSM RLA

CPICH RSCP

t

5 seconds

IRATCC toWCDMA

CPICH Ec/No> FDDQMIN CPICH RSCP >

GSM RLA+ FDDQOFF

IRAT CC GPRS UMTS

IRAT Cell Change: GPRS to WCDMA53


o FDDQMIN is the minimum quality of a WCDMA cell for cell

reselection.

It provides a sufficient quality of the candidate WCDMA cell.

o FDDQOFF is the key parameter to control the behavior of the

IRATCC.

It defines an offset between signal quality of WCDMA and GSM

cells.

CPICH E c /N o > FDDQMIN

&

CPICH RSCP > RLA (serving +neighboring GSM cells) + FDDQOFF

(period time of 5 seconds)

RLA ( Received Level Average): average of the received signal levels

measured in dBm for all monitored GSM frequencies in the BA list

IRAT CC GPRS UMTS

54




28

o Percentage of idle TCH in the serving cell ≤ ISHOLEV

o CPICH Ec/No > MRSL

Filtering

Allocation reply

Inter System Handoveralgorithm

ISHOLEV = 20 %

Organizing the list

Urgency condition

Basic ranking

Radio Network functions

evaluations

Sending the list

WCDMA Cellmeasurement

Traffic load

TTTTSTB

% idle TS: 1/6 ≈ 16, 7%

Add WCDMA cell

to candidate list

% idle TS

≤ ISHOLEV

Ec/No

> MRSL

IRAT HO GSM UMTS

IRAT Handover: GSM to WCDMA55


RBS

1: Ensure that Eb>Ebmin

2: Modify Ebmin to ensure that BLER < BLERmaxRNC

UEPower control frequency = 1500 per second (at each TS)

Power Control

Power Control: Inner & Outer loop power control 56




29

Admission control: controls system load to maintain a sufficient

resources for urgent requirements and an acceptable service quality

for connected users .

It’s based on following inputs:

Downlink transmit carrier power

Air-interface Speech Equivalent (ASE) usage in uplink and

downlink Spreading Factor usage

Code tree usage

Number of Compressed Mode radio links

Admission Control

57


speech)factor(activity

link)radiofactor(activity

speech)link radio(maxrate

link)radio(maxrate⋅= ASE

ASE of a radio link = relative value, defined as the air-

interface load relative to a speech radio link (12.2kbps,

50% activity).

A radio link with an ASE of 3 in DL, is expected togenerate as much interference in downlink as 3 speech

radio links in the cell.

General method of estimating ASE value for a specific

service:

58

Admission Control




30

ASE value for AMR: not equal to one due to the control

signaling (3.4 kbps) which contributes with 0.6 ASE

Admission control: ASE for different RABs

59

Admission Control


DL transmit carrier power : to keep sufficient power for UE’s in

CM or experiencing a poor service quality due to fading

SF usage: Provides details about the number of codes of a certain

length that are in use. Limit the number of users of a certain SF. Code tree usage: Provides a measure for code tree usage in the

downlink. Monitoring of this dedicated resource based on the

tracking of the fraction on the downlink code tree in use

Compressed mode radio links: Indication of the processor load

that the Compressed mode radio links causes in the RBS. Important

due to hardware limitations in the RBS

60

Admission Control




31

Resource request Is admission blockedby Congestion Control?Is admission blocked

by Congestion Control?

Yes,thenblock

Check if the requestedASE UL + estimated ASE UL

>aseUlAdm

Check if the requestedASE UL + estimated ASE UL

>aseUlAdm

No

Yes,thenblock

Check if the requestedDL Pwr + estimated Pwr

>pwrAdm

Check if the requestedDL Pwr + estimated Pwr

>pwrAdm

No

Yes, then block

Check if the requested +estimated # compressed mode RL

>compModeAdm

Check if the requested +estimated # compressed mode RL

>compModeAdm

No

Yes,thenblock

No, thenaccept

Check if the requestedASE DL + estimated DL ASE

>aseDlAdm

Check if the requestedASE DL + estimated DL ASE

>aseDlAdm

No

Yes,thenblock

Yes,then

block

Check if the requestedcode usage + estimated code usage

>

dLCodeAdm

Check if the requestedcode usage + estimated code usage

>dLCodeAdm

No

No

Yes,thenblock

Check if the requestedDL SF + estimated DL SF

>sfXAdm *

Check if the requestedDL SF + estimated DL SF

>sfXAdm *

Only checked if

BE-service requests

* X = 8 or X = 32

Admission control workflow61

Admission Control


Main goal of the Congestion Control function = provide the ability to

solve overload situations.

Overloads occur due to a natural process caused by fluctuations in the

downlink power. Factors like fading, inter-cell interference, and

variations in the traffic on individual connections can cause thesefluctuations.

Congestion Control is triggered only in the case of (near) overload in

a cell

Congestion control based on 3 consecutive steps:

1. Restricts admission

2. Delay packet transmission, by reducing the packet bit rate

3. If this does not solve the congested situation, it releases radio links

until congestion ceases 62

Congestion Control




32

Time

DL Power

pwrAdm +pwrAdmOffset

= pwrHyst

75ms 100ms

= tmCongAction

StartreleaseAseDl

StartreleaseAseDl

100ms

= pwrHyst

pwrOffset

StoppreleaseAseDl

< pwrHyst

200ms

Congestion Congestionsolved

Congestion control handling 63

Congestion Control


Core Network

SRNC&

DRNC

Iu

Iur

over Iur:

SRNC

Iu

over Iu:

1. Best Effort users in HOBest Effort users

3. CS users in HOCS users

5. Speech users in HOSpeech users

2. Best Effort users in HOBest Effort users

4. CS users in HOCS users

6. Speech users in HOSpeech users

Congestion control: ASE release order 64

Congestion Control




33

2. UMTS2. UMTS

CHANNELSCHANNELS

65

66

Codes, physical and logical channels (1)Codes, physical and logical channels (1)

2 spreading codes used in UMTS:

– Channelisation codes: derived from the OVSF

(Orthogonal Variable Spreading Factor ) tree. Vary

the spreading factor to keep codes orthogonality.

In the same cell: OVSF codes can not be all used

together.

– Scrambling codes: each cell has its own code.

Allow to differentiate neighboring cells. Chosen

among 512 (reuse pattern = 512). For the mobiles:

224 different codes. Random allocation.



36

71

WCDMA systems specificities (1)WCDMA systems specificities (1)

• Main features and constraints:− Node B power: shared among the N connected mobiles,

− Noise maximum power: 10 dB,

− Transmission power: between 6 and 10 dB,

− Transmission power on each level: depends on propagationconditions and activated service,

− Mobiles distribution in the cell: if the mobiles are close to theNode B, capacity can be up to 10 times that of when the mobileare far from the Node B,

− Cell breathing: access management achieved by call admission

control based on the noise rise and load control,

− Power control is fundamental for the UL: outer loop to adjustthe target power according to the BER estimation and fast power control against fast fading. Fast power control continuoustransmission on the radio interface, packet transmission at layer 2.

72

Relation between power and service bitrate

Pr

Voice service

Pr

Email service

Pr Video service

Pe

Power

level of the

signals

received by

the mobiles

Power transmitted by

the Node B

WCDMA systems specificities (2)WCDMA systems specificities (2)



37

73

3. UMTS networks3. UMTS networks

planningplanning processprocess

74

UMTS planning processUMTS planning processMultiservice

offered traffic

Traffic analysis

WCDMA link budget

Cell number

Required channel number for theconsidered configuration

Maximum cell range

Number of carriers per cell



38

Nominal PlanningNominal PlanningNominal PlanningNominal Planning Based on the result of network dimension, preliminary design

present Information of theoretical sites including following:

Site coordinates.

Engineering parameters such as Antenna height, azimuths and tilts.

Radio parameters such as scrambling code ,transmit power of

different channels , etc.

75

• Simulation

– Unlike GSM network, in CDMA coverage and capacity are too inter-

related to be predicted accurately. Monte Carlo simulation is used to

evaluate the performance of a radio network.

– Monte Carlo is a static simulation

During Monte Carlo simulation, the performance of the network is analyzed over

various instances in time (snapshot), where UEs are in statistically determined

places with the given traffic model. The ability of each terminal to make its

connection to the network is calculated through an iterative process.

WCDMA simulationWCDMA simulation



39

SetupSetup

networknetwork

DesignDesign

Run PilotRun Pilot

FieldField

StrengthStrength

PredictionPrediction

PilotPilot

LevelLevel

OK?OK?

RunRun

UMTSUMTS

TrafficTraffic

simulationsimulation

Make predictionsMake predictions

(Services)(Services)

PerformancePerformance

RequirementsRequirements

Fulfilled?Fulfilled?

NeighborsNeighbors

planning&planning&

Scrambling codeScrambling code

allocationallocation

RNP Input &RNP Input &

EquipmentEquipment

configurationconfiguration

NeighborhoodNeighborhood

planning criteriaplanning criteria

Scrambling codeScrambling code

allocation criteriaallocation criteria

OutputOutput

parametersparameters

YESYES

NONO

YESYES

NONO

Traffic modelTraffic model

& forecast& forecast

Simulation flowSimulation flow--chartchart

77

Simulation outputSimulation output

• Simulation output：– Pilot coverage (Ec, Ec/Io) in the

target areas

– Best server plot

– Coverage probability distribution of each service

– Access failure distribution andstatistic of each service

– Continuous coverage areas of eachservice

– Cell load distribution of downlink and uplink

– Pilot pollution distribution

– Soft handover areas statistic of eachservice



40

• For each theoretical site, a physical site will be acquired in this phase

through following steps:

Define search areas

Site ranking

Identify candidate sites

Site acquisition

Site SurveySite Survey

A suitable physical site

Give adequate radio coverage.

Have connectivity into the transmission network.

Be politically acceptable to the local community.

Have power nearby, good access and a co-operative owner.

A3rd

D1st

C2nd B - Unsuitable

79

Verification by system simulationVerification by system simulation

• It is an iterative process to

verify the final design until all

the requirements are fulfilled

Coverage prediction

RNP

Planning

results

Are requirements

Fulfilled?

Traffic distributionSystem simulation

80



41

81

4. CDMA link4. CDMA link

budgetbudget

UL dimensioningUL dimensioning

Lpmax = PUE – SRBS – BIUL - Bpc - BLNF - LBL - LBPL - LJ + Ga

BIUL = 10*Log ( )1

1 - QUL

QUL = M ((for 1 cell) / Mpole

QUL = M / (3 *N *Mpole) N1 =3* Mpole * QUL

MCapacity

Lpmax = a + b*log(R)

Sc (cell area) = 9/8√3 * R2 N2 =

S (total area )

Sc (cell area)Coverage

82



42

DL dimensioningDL dimensioning

Lsa = Lpmax + Bpc + BLNF +LBL + LBPL + LJ - Ga

Ptot =

PCCH + H *

Lsa 1 - QDL

Lpmax = Ptot – SUE – BIDL - Bpc - BLNF - LBL - LBPL - LJ + Ga

Lsa = Ptot – SUE – BIDL

BIDL = 1 + K *Ptot

Lsa

1

2

3

4

1

3 4

2

?

83

84

Link budgetLink budget

First dimensioning realized according to

the coverage: compute cell size for the

most constraining services.

- Uplink : MAPL, cell size determination,

- Downlink : Link budget balancing to

determine the BS power. BS power shared

by all the channels (common and traffic).



43

85

NodeNode B transmission powerB transmission power

- 37 dBm (5 W): low capacity and extended

coverage,

- 40 dBm (10 W): good coverage and medium

capacity,

- 43 dBm (20 W): good coverage and large

capacity per carrier,

- 46 dBm (40 W): large capacity and wide

coverage.

86

Power classesPower classes

EIRP (dBm)

Node BUE Macro Micro Pico

[40, 43] [30, 43] [20, 43] [10, 33]



45

89

L p (dB) = Pt (dBm) + Gt (dBi) – Pr (dBm) + Gr (dBi)

= EIRP (dBm) – Pr (dBm) + Gr (dBi)

EIRP depends on the UL or DL.

UL/DL link budgetUL/DL link budget

Uplink (UL) Downlink (DL)

EIRP (dBm) =

PTx (dBm) – Lu (dB) + Gt (dBi)

EIRP (dBm) =

PTx (dBm) – Lc (dB) + Gt (dBi)

PTx: transmission power,

Gt : antenna gain, Lu: body loss (voice: [3, 10],

data: [0, 3]).

PTx: transmission power,

Gt : antenna gain, Lc: feeder losses.

90

Noise rise versus number of subscribers per cell

Link Budget parameters (3)Link Budget parameters (3)

0

2

4

6

8

10

12

0 10 20 30 40 50 60

Nombre d'abonnés / cellule

N o i s e R i s e

( d B )

Number of subscribers per cell



46

91

Planning/Dimensioning of thePlanning/Dimensioning of the

cell for the ULcell for the UL

RTraffic assumptions

Code/channel number required for the maximum estimated traffic

Noise rise value (statistical approach based on a mix traffic)

Link budget computation (Uplink)

MAPL computation

R’: Maximum radius of the cell determined with a propagation model

- If R’ > R and Noise Rise < Max( Noise Rise) => New iteration with R’’> R

- Otherwise, add capacity (new carrier or new station) and repeat with new configuration

92

DL analysis (1)DL analysis (1)

(a) Area of radius R.

(b) Traffic models Mean potential traffic in the area.

(c) Estimated traffic Compute the number of required

channels.

(d) For each user, estimate the required power for each link.(e) Distribution of users in the cell and soft handover or not

compute BS power transmission.

(f) Link budget established to determine the MAPL in the

cell.

(g) The process repeats in (a) until BS power value is lower

or equal to its maximum power.



47

93

Steps:− BS total power = summ of the powers of all the

established links taking into account the mobilessensitivities and propagation losses (estimated with apropagation model). Additional power for controlchannels. If no BS power is above its maximumpower, no link is deleted and the CIR value iscomputed for each mobile.

− After determination of total BS power: distributionof the power among the various channels (pilotchannel, synchronisation channel, traffic channel).

Simulations stop: Most used criterium: powerfluctuations.

DL analysis (2)DL analysis (2)

94

UL power budget (example for 144 kb/s data service)UL power budget (example for 144 kb/s data service)

Value Formula

Transmitter

P: MS Tx Power (dBm) 23

MAG: MS TxAntenna Gain (dBi) 0

BL: Body Loss (dB) 3

PIRE: MS EIRP (dBm) 20 EIRP= P+MAG-BL

Receiver

FM: Fade Margin (dB) 5,4 FM = 0,675*SD (RC=90%, SD=8dB)

IM: Interference Margin (dB) 3 IM = 10log(1/1-loading)

PL: Pathloss (dB) 0 Dense Urban = 20 dB

BAG: BTS Antenna Gain (dBi) 16

BCL: BTS Cable Loss (dB) 3

SHG: Soft HO Gain (dB) 2

TM: Total Margin (dB) -6,6 TM=FM+IM+PL-BAG+BCL-SHG

S: BTS Rx Sensitivity (dBm) -115

UL_PL: UpLink Path Loss (dB) 141,6 UP_PL = EIRP-TM-S



48

95

DLDL linklink budgetbudgetValue Formula

Transmitter

P: BTS Tx Power (dBm) 29 Power allocated to the pilot channel

BAG: BTS Tx Antenna Gain (dBi) 16

BCL: BTS Cable Loss (dB) 3

PIRE: BTS EIRP (dBm) 42 PIRE = P+BAG-BCL

Receiver

FM: Fade Margin (dB) 5,4 FM = 0,675*SD (RC=90%, SD=8dB)

IM: Interference Margin (dB) 3 IM = 10log(1/1-loading)

PL: penetration loss (dB) 0 Dense urban = 20 dB

MAG: MS Antenna Gain (dBi) 0

SHG: Soft HO Gain (dB) 2

TM: Total Margin (dB) 9,4 TM=FM+IM+PL-MAG+BL-SHG

S: MS Rx Sensitivity (dBm) -110

DL_PL: DownLink Path Loss (dB) 142,6 UP_PL = PIRE-TM-S

96

5.5. LoadLoad factor andfactor and

noise noise rise rise



49

Uplink limited capacity: uplink Mpole values

Uplink: M pole

97

Pole capacityPole capacity

Uplink: Noise Rise

Uplink interference degrade the RBS sensitivity with a

margin of BIUL ,calculated as following

Where Q is the system load: Q = + +M1

Mpole

M2

Mpole

Mn

Mpole

M1,…. Mn are the number of users on services 1 … n

98

Noise riseNoise rise



50

Uplink: Noise RiseUplink: Noise RiseRB S S e n s i t i vi t y

System load (Q)

100 %

99

Downlink: MDownlink: Mpolepole

γ : Downlink C/I targetε: C/I compensation term for fast fading

α: Non orthogonality factor

nAS: Typical size set

b: Number of active links

κ : Fraction of user in soft/softer handover

GSHO: Soft HO gain

GDTX: DTX gain 100



51

Downlink limited capacity: Downlink Mpole values

Downlink: MDownlink: Mpolepole

101

102

Load factor on the UL (1)Load factor on the UL (1)

W : chip rate (3,84 Mchip/second),

ρ i: E b /N 0 (QoS) required for service i (or for the correspondingservice of user j),

i = inter-cell interference/ inner-cell interference. i depends on theenvironment, the type of the cell (i = 55 % in case of omnidirectional cells) and the type antenna,

R j: user j rate, depends on the used service,

u j: user j activity factor at physical layer level (67 % for voice and100 % for data),

N s: number of sectors,

ζ: sectorization gain.

( )∑ +

+

=k

sk

k k

/ N .i1.u

R.W 1

1 ζ

ρ

η



52

103

Load factor on the UL (2)Load factor on the UL (2)

W : chip rate (3,84 Mchip/second),

R j: j user bitrate, depends on the service,

u j: user j activity factor at physical layer level (67 % for

voice and 100 % for data),

N : number of subscribers in each cell.

The higher the load, the lower the radius.

Cell breathing.

∑

++=

=

N

1 j j

j

j0

b

UL u.

R. N

E

W 11)i1(n

104

Noise RiseNoise Rise• Noise Rise = - 10log

10(1 – n

ul).

• Value used as interference margin in the calculationof the link budget. Increases with transmissionbitrate and the number of communications.

Capacity of the system defined by the pole capacity.

C orresponds to the case where nul reaches1.Pole capacity never reached as it assumes infinite

mobile transmission powers.

In practice: Maximum WCDMA cell load between40 and 70 %.

Example: Load between 20 and 50 % noise rise =2 dB.



53

Downlink: Noise Rise Downlink: Noise Rise

Downlink interference degrade the UE sensitivity

with a margin of BIDL ,calculated as following ;

Lsa

= Lpmax

+ Bpc

+ BLNF

+ LBL

+ LBPL

+ L j

– Ga

Nt: thermal noise power density (-174 dbm/Hz)

Nf : Noise figure

Where

105

Cell breathingCell breathing

Cell breathing phenomena

RBS

Q = Qmax = 60 %

Q = 0 % (no traffic)

106



54

107

Cell breathing phenomenaCell breathing phenomena

Case 1: 10 users Case 2: 20 users

-10 < C/I < -5 dB -15 < C/I < -10 dB

-15 < C/I < -50 dB cells

108

Capacity, cell radius andCapacity, cell radius and noise rise noise rise

R

Charge de la cellule = 20 % de

la capacité maximum

Niveau d’inter férence = y dB

RR’

Charge de la cellule = 50 % de

la capacité maximum

Noise Rise = 2 dB

Niveau d’inter férence = y + 2 dB

R

R et R’ sont les rayons descellules dans les deux

situations de charge

Cell load = 20% of the

maximum capacity

Interference level = y dB

R and R’: cellradiuses in the 2 load

conditions

Cell load = 50% of the

maximum capacity

Interference level = y + 2 dB



56

111

6. Coverage and6. Coverage and

servicesservices

112

Coverage and services (1)Coverage and services (1)Link budget Service throughput

Relation between coverage and service throughput

Yellow = 12.2 kbps – Orange = 64 kbps - Red= 384 kbps



57

113Blue = 144 kbps – Red = 384 kbps

Coverage and services (2)Coverage and services (2)

114

Traffic location and BS capacityTraffic location and BS capacity

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58

115

Benefits for locating the sites close toBenefits for locating the sites close to hot spots hot spots

− Minimises the power on downlink channels;

− Reduction in the number of mobiles in soft handover and increase in the BS averagecapacity;

− Reduction of the interference on the uplink ;

− Increase of BS capacity: terminals close to theBS require less power and thus minimise the DLinterference. Furthermore, mobiles connected toneighbour base stations de base being far fromcurrent one, inter-cell interference is low, andthus increasing the capacity of the neighbour BSon the UL.

116

Coverage/capacity versus distance (1)Coverage/capacity versus distance (1)− High bitrates = high power,

− High transmission bitrates only available close

to the base station.



59

117

Coverage/capacity versus distance (2)Coverage/capacity versus distance (2)

HSDPA capacity limitsHSDPA capacity limits

118

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