WCDMA Initial Tuning Introduction

8/11/2019 WCDMA Initial Tuning Introduction

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HUAWEI TECHNOLOGIES Co., Ltd. HUAWEI Confidential

WCDMA

Initial TuningIntroduction


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HUAWEI TECHNOLOGIES Co., Ltd. HUAWEI Confidential 1 Page 1

WCDMA Overview

WCDMA Capacity

WCDMA Physical Layer

WCDMA Handover

WCDMA RNO Principles and Procedures


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HUAWEI TECHNOLOGIES Co., Ltd. HUAWEI Confidential 2

Realize 11 frequency reuseThe capacity per WCDMA cell is soft for

it is related to environment and neighbor

cell interference.

Supports multiple services with differentspeed rate and QoS, and each service

has different coverage range.

Adopts cellular network structure andfrequency planning to guarantee

intra/inter-frequency interference

Users supported can be calculated from

carriers and timeslots if the interference

meets the requirements.

Provides voice service

Difference between WCDMA and GSMGSM WCDMA

64K 12.2K 144K 384K


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BSC6800 cabinet appearance

RNC & NodeB Appearance

BTS3900 cabinet appearance


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QoS TypeR e

al - t i m

e c a t e g or

y

Conversationa

l

It is necessary to maintain the time relationshipbetween the information entities in the stream. Small

time delay tolerance, requiring data rate symmetry

Voice service,videophone

Streaming

Typically unidirectional services, high requirements on

error tolerance, high requirements on data rate

Streaming

multimedia

N onr e

al - t i m

e c a t e g or y

Interactive

Request-response mode, data integrity must be

maintained. High requirements on error tolerance, low

requirements on time delay tolerance

Web page

browse,

network game

BackgroundData integrity should be maintained. Small delayrestriction, requiring correct transmission

Backgrounddownload of

Email


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WCDMA Overview

WCDMA Capacity


WCDMA Handover



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Capacity Restriction Factors

The WCDMA network capacity restriction factors in theradio network part include the following:

Downlink power

Downlink channel code resources (OVSF)

Channel element (CE)

Iub interface transmission resources


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Downlink Channel Code Resources

Following is an example of code resources allocation


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Channel Element (CE)The Channel element the quantitative data that measures the

resources logically occupied for service processing

The resource occupied by the service processing is mainly related

to the spreading factor of this service. The smaller the SF is, the

greater the data traffic will be, and more resources will be occupied

The SF of typical services are:

AMR12.2kbps SF=128

CS64kbps SF=32

PS64kbps SF=32

PS144kbps SF=16

PS384kbps SF=8


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Iub Interface Capacity

The contents transmitted on the Iubinterface include:

The user data encapsulated in the

AAL2 format (common channel and

dedicated channel)

Signaling data encapsulated in the

AAL5 format

BTS operation & maintenance data


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WCDMA Overview

WCDMA Capacity


WCDMA Handover



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UTRAN Protocol Structure

RNS

RNC

RNS

RNC

Core Network

NodeB NodeB NodeB NodeB

Iu Iu

Iur

Iub IubIub Iub

UTRAN:UMTS Terrestrial Radio Access Network


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Spreading TechnologySpreading consists of 2 steps

Channelization operation, which transforms data symbols into chips. Thusincreasing the bandwidth of the signal, The number of chips per datasymbol is called the Spreading Factor SF .The operation is done bymultiplying with OVSF code.Scrambling operation is applied to the spreading signal .

Data bit

OVSFcode

Scramblingcode

Chips afterspreading


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Scramblingcodes fordownlink

physicalchannels

Set 0

Set 1

Set 511

512 sets

Scrambling Code (SC)


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WCDMA radio interface has threekinds of channels

In terms of protocol layer, the WCDMA radio interface has threechannels: Physical channel, transport channel and logical channel.

Logical channel: Carrying user services directly. According to the typesof the carried services, it is divided into two types: Control channel andservice channel.

Transport channel: It is the interface of radio interface layer 2 and

physical layer, and is the service provided for MAC layer by thephysical layer. According to whether the information transported isdedicated information for a user or common information for all users, itis divided into dedicated channel and common channel.

Physical channel: It is the ultimate embodiment of all kinds ofinformation when they are transmitted on radio interfaces. Each kind of

channel which uses dedicated carrier frequency, code (spreading codeand scramble) and carrier phase (I or Q) can be regarded as adedicated channel.


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Control channel

Traffic channelDedicated traffic channel (DTCH)

Common traffic channel (CTCH)

Broadcast control channel (BCCH)

Paging control channel (PCCH)

Dedicate control channel (DCCH)

Common control channel (CCCH)

Logical Channel


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Dedicated Channel (DCH)

-DCH is an uplink or downlink channel

Broadcast channel (BCH)

Forward access channel (FACH)

Paging channel (PCH)

Random access channel (RACH)

High-speed downlink shared channel(HS-DSCH)

Common transportchannel

Dedicated transportchannel

Transport Channel


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Downlink Physical ChannelDownlink Dedicated Physical Channel

(Downlink DPCH)

Downlink Common Physical ChannelCommon Control Physical Channel (CCPCH)

Synchronization Channel (SCH)Paging Indicator Channel (PICH)

Acquisition Indicator Channel (AICH)Common Pilot Channel (CPICH)High-Speed Packet Downlink Shared

Channel (HS-PDSCH)High-Speed Shared Control Channel

(HS-SCCH)

DownlinkPhysical Channel


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Uplink Physical ChannelUplink Dedicated Physical Channel

Uplink Dedicated Physical DataChannel (Uplink DPDCH)Uplink Dedicated Physical ControlChannel (Uplink DPCCH)High-Speed Dedicated Physical

Channel (HS-DPCCH)

Uplink Common Physical Channel

Physical Random Access Channel

(PRACH)

Uplink PhysicalChannel


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Function of physical channel

Node B UE

P-CCPCH-Primary Common Control Physical ChannelSCH- Synchronisation Channel (Including P-SCH and S-SCH Channel)

P-CPICH-Primary Common Pilot ChannelS-CPICH-Secondary Common Pilot Channel

Cell b roadcast chann els

DPDCH-Dedicated Physical Data Channel

DPCCH-Dedicated Physical Control Channel

Dedicated channels

Paging channels

PICH-Paging Indicator Channel

S-CCPCH-Secondary Common Control Physical Channel

PRACH-Physical Random Access Channel

AICH-Acquisition Indicator Channel

Random access channels

HS-DPCCH-High Speed Dedicated Physical Control Channel

HS-SCCH-High Speed Share Control Channel

HS-PDSCH-High Speed Physical Downlink Share Channel

High speed downl ink share channels


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WCDMA Overview

WCDMA Capacity


WCDMA Handover



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HUAWEI TECHNOLOGIES Co., Ltd. HUAWEI Confidential 26 Page

Why mobile systems need handover?

Mobile systems are composed by cells

which the coverage is limited.

The mobility of the UE.

Providing the continuous service - the

basic element in QoS.


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Soft Handover (Connection before Disconnection)

RNCNodeB1 NodeB2


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Softer Handover (A Special Case of Soft Handover)

RNCNode B

Cell A Cell B


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Hard Handover- (Disconnection before Connection)

RNCNodeB1 NodeB2


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Basic Concepts about Handover

Active set

monitor set

Detection set

Event report

Event to periodic report

Periodic report

Radio link (RL)

Radio link set (RLS)

Maximum-ratio combining

Selective combining

Soft handover gain

Pilot channel (CPICH)


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E t R t


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Event Report


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Event Report


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Summary - Categories of Handover

According to the signaling characters

Soft handover (softer handover)

Hard handover

According to the properties of source cell and target cell:

Intra-frequency handover

Inter-frequency handover

Inter- RAT handover (UMTS GSM/GPRS)

According to the purpose of handover:

Based on Coverage

Based on Noncoverage


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Brief Introduction

Single Site Verification

Radio Frequency Optimization

Parameters Optimization

KPI Overview


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To enhance network performance

--- e.g. coverage/accessibility/mobility

To resolve specific issues

--- e.g. interference/coverage

To improve subscribers QoE

--- e.g. service quality/drop calls

To enhance network stability--- e.g. traffic increase/upgrade

Network Optimization Target

O i i i h h Lif C l


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Const ruc t ion phaseTroubleshooting

Boom i ng phasePotential Seeking

Mature phaseBalancing

Time

S u b s.N

um b er

RF plan review

Single site verification

Pre-launch optimization

KPI analysis ComplaintsDT & CQT

Customized anddifferentiated

services

Billing strategies

Drop call

CongestionPoor quality

Access failure

RF adjustment

Para. adjustment Maintenance and upgrade

Network expansion

.

InvestmentReturn

Commercia llaunch

Optimization throughout Life Cycle


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Network Optimization Phases

RF optimization

Y

N

N

Y

Single site verification

80 sites in thecluster ready?

Service test andparameter optimization

Routine drive test andstats. analysis

Acceptance criteria

satisfied?

New site integrated

Optimizationpreparation

Acceptance


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Brief Introduction




KPI Overview



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Site Verification TargetTo verify cell coverage

CPICH RSCP

To investigate interference

NodeB RTWP & CPICH Ec/Io

To verify site installation

e.g. PA/antenna/feeders issues

To check service functionCS call & PS attach/detach


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Site Verification Items Cell basic information confirm

Item: frequency, SC, LAC/RAC

Tool: engineering UE

Purpose: basic parameters check

Cell coverage verification Item: CPICH RSCP

Tool: engineering UE or scanner

Purpose: identify equipment issues

--- e.g. PA, antenna, feeder connection, etc


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Site Verification Items Cell interference investigation

Item: NodeB RTWP, CPICH Ec/Io

Tool: NodeB LMT, engineering UE or scanner

Purpose: UL/DL interference investigation

Service function verification Item: voice (MO/MT), VP (MO/MT)

PS attach/detach, PDP activation

Tool: engineering UE Purpose: CS/PS service function check


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An example Check list

Example: Site Verification Checklist

Single Site Verification Checklist

Site expanded from:Site migrated from RNC:

New site Expansion

Site Connected to RNC:

Idle mode

Note: If the item is OK, mark the " " before it by " " otherwise, mark the" " by " ". If the item is not check, mark the " " before it by "/".

HSDPA 10 Normal function to access HSDPA

Migration Others

New Site:Site Expansion:

Reminder

Mapinfo Update Data Base Update

To:To RNC:

Site Name:

Remarks

CPICH_RSCP > 75 dBm near site

Coverage DT 9 Check by DT whether the overall quality of service and cov

Connected mode

6

Mobile originated and terminated calls of VP service8 Connection of PS services

Mobile originated and terminated calls of voice services7

CPICH_EcIo > 8 dB near site

Site ID:

No. Activity/Process

Site MigrationOthers

3 LAC/RAC data configuration

1

4

2 Scramble configurationFrequency configuration

5

Remarks (further explanation):

2-Name/Designation: Signature: Date:

Reviewed by:1-Name/Designation: Signature: Date:

l d d


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Brief Introduction




KPI Overview



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RF Optimization Target

To optimize coverage

To minimize pilot pollution

To optimize cell dominance

To optimize neighbor cell list

To resolve RF-related drop calls

RF O i i i P d


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RF Optimization ProcedureDrive test

Identify RF issues

Identify candidatecells for changes

Identify nature ofrequired changes

Determine amountof changes

Implement changes

Repeat drive test

Finished

N

Problem resolved?Y

RF P O i i i


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RF Parameters Optimization

Engineering parameters adjustment

To adjust antenna down tilt

To adjust antenna azimuth

To adjust antenna location

To adjust antenna height

To replace antenna

To replace site

To add new cell

Radio part parameters adjustment To optimize neighbor cell list


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omni directiondirectional Antenna

Antenna


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Outline

A P


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Symmetric half-wave dipole PatternTop view

side view

directional antenna pattern omni antenna pattern

Antenna Pattern


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GainThe radiation ability of certain antenna overtop dipole or isotropic

Indicates the antenna feature of electromagnetic radiation in specific

directions

Unit: dBi/dBd

theory source

l/2 antenna Direction antenna

dBd

dBi

dBi =dBd+2.15

dB/dBm?


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Forward to Back Ratio

The ratio of main lobe signal strength to back lobeThis value is within 18 45dB. In urban, it is suggested to use the

antenna with high F/B ratio


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Beam Angle

HPBW: Half Power Beam WidthLobe angle between two points, the power of which reduce to

the half of that of the maximum radiate direction

Vertical HPBW and Horizontal HPBW

60

(eg) Peak

- 3dB

- 3dB

15

(eg) Peak

Peak - 3dB

Peak - 3dB

Horizontal sectionVertical section


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Down tilt

To control coverageRealization: electron and mechanism


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mechanism

electron

Down tilt


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Effect of Electron Down tilt

No Down tilt Electron Down tilt


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Effect of Mechanism Down tilt

No Down tilt Mechanism Down tilt


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Effect of different methods

10

(E) 10

(M)6

(E)+ 4

(M)


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Principle for Downtilt Mode SelectionCom parison betw een Mech anical Dow nti l t and Electr ic Down ti l t

CPICH Coverage Optimization


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CPICH Coverage Optimization

Ways to optimize:(1)Adjust ant. azimuth or tilt;(2)Increase ant. height;(3)Replace high-gain antenna;(4)Add new cells;

Ways to optimize:(1)Adjust ant. azimuth or tilt;(2)Decrease ant. height;(3)Adjust CPICH power

Ways to optimize:(1)UL or DL coverage limited?(2)Optimize UL or DL

interference

Poor coverage cells

Over shooting cells

UL & DL coverage imbalance

CPICH coverage analysis:

Poor Coverage: Example


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Poor Coverage: Example

Cell Dominance Optimization


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Cell Dominance Optimization

Cells with no dominance at allTo indicate the site not radiating

or to indicate antennas blocking

Cells with excessive or poor dominanceDue to non-optimum antenna tilts

or due to a high site

Areas of non-dominance Due to no a single clear dominant cell

Cell dominance analysis:

Site vis i tneeded

(1) Frequent soft HO

(2) Interference to adjacent

cel ls

Poor Cell Dominance: Example


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Poor Cell Dominance: Example

RF Analysis Approaches CPICH


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RF Analysis Approaches CPICHCoverage

Check areas of poor coverage, suggestion value as

below:

Good: RSCP -85 dBm

Fair: - 95 dBm RSCP < -85 dBm

Poor: RSCP < - 95 dBm

Examine the RSCP coverage on per cell bases in order

to highlight any cells that have too large a footprint.

RF Analysis Approaches


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RF Analysis Approaches InterferenceCPICH Ec/Io Plot

Good: Ec/Io -8 dB

Fair: - 14 dB Ec/Io < -8 dB

Poor: Ec/Io < - 14 dB

The -8 dB threshold takes into account the expected futureinterference

increase as a result of increased traffic.



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RF Analysis Approaches Interference

Because the RSCP Level isPOOR, the fundamental cause

of low Ec/Io isPOOR COVERAGE

-15.5

-104

-20

-19

-18

-17

-16

-15

-14

Ec/Io RSCP

-120

-115

-110

-105

-100

-95

-90

Whats the

problem?



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RSCP level is GOOD, this willimply strong SYSTEM

INTERFERENCE

-15.5

-63

-20

-19

-18

-17

-16

-15

-14

Ec/Io RSCP

-90

-85

-80

-75

-70

-65

-60 Whats theproblem?



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RF Analysis Approaches UL


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RF Analysis Approaches ULCoverage

Uplink Coverage (UE Tx Power)High UE Tx power means possible poor uplink coverage.

Areas of high Tx power should be compared to the CPICH

pilots to verify if the problem only exists on the uplink.

RF Analysis Approaches UL


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RF Analysis Approaches ULCoverage


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HUAWEI TECHNOLOGIES Co., Ltd. HUAWEI Confidential 73 73

Pilot pollution exists if all the following conditions are met:

The number of pilots that meet the following condition is more than ThNCPICH_RSCP > ThRSCP_Absolute

(CPICH_RSCP1st - CPICH_RSCP(ThN +1)th)< ThRSCP_Relative

Assume that ThRSCP_Absolute = 100 dBm, ThN = 3, and ThRSCP_Relative = 5 dB

Then pilot pollution exists if all the following conditions are met:More than three pilots meet the following condition CPICH_RSCP > 100 dBm.(CPICH_RSCP1st - CPICH_RSCP4th) < 5 dB

RF Analysis Approaches Pilot Pollution

RF A l i A h Pil t P ll ti


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RF Analysis Approaches Pilot Pollution

ThRSCP_Relative was set 5 dB here


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Neighbor Cell List Optimization


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e g bo Ce st Opt at o

Data collection: drive test

Data comparison: scanner, UE

How to optimize?

How to optimize neighbor cell List?(1)Compare coverage difference b/w

Scanner and UE(2) Add missing neighbor cells

(3) Remove useless neighbor cells

Neighbor list classification:Intra-freq. neighbor cell list

Inter-freq. neighbor cell list

Inter-RAT neighbor cell list

Neighbor cell list influences:

(1) Service Handover (drop call)(2) Cell Reselection

Drive test (service test):

Drop calls during moving

RF-related Drop Calls


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Poor coverage

High interference

Poor UL coverage

Poor dominance

Pilot pollution

Missing neighbors

Problems

Fas t change of RF condi t ions usu al lycaus es drop calls , e.g. turn ing a co rner.

Poor RSCP & Ec/Io

Poor Ec/Io or RTWP

UE max Tx power

many SHO events

many cells present

Appearance

RF Analysis Approaches Drop


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RF Analysis Approaches DropCall

Drop Call Analysis Example 1

Call Drop

RSCP & Ec/Io degradesBOTH for scanner and UE

Check for Coverage problems

RF Analysis Approaches Drop


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RF Analysis Approaches DropCall

Drop Call Analysis Example 2

Call Drop

Ec/Io (and RSCP) degrades for UE ONLYwhile scanner shows no degradation

UE camp on new cell immediatelyafter drop, and UE did not

measure this cell before Drop

Check the Neighbor


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WCDMA RNO P i i l d P d


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Brief Introduction


Radio Frequency OptimizationParameters Optimization

KPI Overview



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Parameters to be Optimized


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Parameters to be Optimized

CCCH power allocation para.

RL maximum power para.

Cell re-selection para.

Intra-freq. handover para.

Inter-RAT handover para.

Power control para.

Access power para.

Other related para.

The influence caused by the cell

parameters adjustment shouldbe analyzed carefully.

Seldom adjusted

An effective way toreduce drop calls



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Brief Introduction


Radio Frequency OptimizationParameters Optimization

KPI Overview


3G OSS KPI


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3G OSS KPI

KPI Analysis: RRC Connection setup SR


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KPI Analysis: RRC Connection setup SRMain reason s fo r fa i led RRC con nect ion s etups :

(1) po or co verage; (2) low FA CH po w er

KPI Analysis: CS RAB setup SR


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KPI Analysis: CS RAB setup SR

Poss ible reaso ns fo r RAB Setup fai lures :

(1) po or cov erage; (2) no enoug h resour ce


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KPI Analysis: Inter-RAT HO SR


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Data disc repancies b etween 3G netwo rk and 2Gnetwo rk h ave direct im pact o n in ter-RAT HO SR.

e.g. BSIC wro ngconf igured

in 3G network

3G DT KPI


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3G DT KPI

3G DT KPI


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3G DT KPI


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WCDMA Initial Tuning Introduction

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