MYCOM Practical WCDMA Course

Mycom Academy - Confidential - Ferri Tafreshi 1

Practical WCDMAPractical WCDMA


AgendaNetwork ArchitectureBasic WCDMA Concepts

Multiple Access MethodsWCDMA CharacteristicsWCDMA Receiver

Design Concepts Link Budget

Uplink DownlinkCPICH

Physical and Logical ChannelsLogical ChannelsTransport ChannelsPhysical Channels


AgendaRadio Resource Management

Power ControlHandover TypesCapacityAdmission Control

Monitoring and OptimizationDrive testingDrive testing results and optimization cases


Network ArchitectureNetwork Architecture


System Architecture

UTRANGGSN

HLR

GMSC

3G-SGSN

Node-B

Node-B

Node-B

Node-B

RNC

RNC

MSC/VLR

Iur

Iub

(optional)

PSTN/ISDN

IP networksIu

MS = Mobile Station (WCDMA)Node-B = Base Station (WCDMA)RNC = Radio Network ControllerSGSN = 3G Serving GPRS Support NodeGGSN = Gateway GPRS Support NodeHLR = Home Location RegisterMSC = Mobile Switching CentreGMSC = Gateway MSCUTRAN = UMTS Terrestrial Radio Access Network


System ArchitectureDue to high bit rate requirements WCDMA has a new air interface modulation compared to other technologies.UTRAN consists of Base Stations and Radio Network Controllers (RNC), which controls the Node-Bs. A base station in WCDMA is called for Node-B. New functionality has been implemented to manage the radio resources.RNC is controlling the Node-Bs. It manages the resource allocation and is responsible for mobility management. Node-B is managing the radio links and power control.


System ArchitectureNew interface has been introduced between RNCs, Iur. (3GPP TS 25.423)Core network elements are evolved from GSM.Subscriber management is based on SIM concept familiar from GSM.Security is based on GSM security principles and mechanisms and enhanced further.


Basic WCDMA ConceptsBasic WCDMA Concepts


Multiple Access Methods: Frequency Division Multiple Access

One user uses one frequency

Time Division Multiple AccessOne user’s channel belongs to himunder a fraction of time and on certainfrequency

Code Division Multiple AccessEvery user is using the same resource buteach user has a code that identifies its information

Frequency

Time

Power

FDMA

FrequencyTime

Power

TDMA

FrequencyTime

Power

CDMA

CODE


WCDMA Basic Characteristics: Wideband-Code Division Multiple AccessDuplex schemes:

Frequency Division Duplex (FDD)Time Division Duplex (TDD)

Channel Spacing: 5MHz on 200kHz rasterFrequency band:

FDD: UL:1920-1980 and DL: 2110-2170TDD: 1900-1920 and 2010-2025Available channels: 12 for FDD and 7 for TDD

User data rates: up to 2Mbit/sChip rate: 3.84McpsModulation:

Data modulation: QPSK (Downlink); BPSK (Uplink)Spreading modulation: QPSK


WCDMA Basic Characteristics: Frame length: 10msInter-BS synchronization:

FDD: AsynchronousTDD: Synchronous (GPS or common clock)

Soft HandoverPower versus Capacity

Capacity limited by interference rather than number of channels

Fast power control1500Hz power control. GSM’s power control rate is 2Hz. This in order to reduce the near-far effect.

Spread spectrum technique:Information is transmitted at a bandwidth much wider than the information rate


WCDMA Basic Characteristics: Users are separated by codes.

Signals from other users would be like noise (interference)WCDMA is interference limited (GSM is frequency limited)

Why would spreading the signal be good?For a given information rate, the wider the bandwidth for transmitting the information, the lower the required signal to noise ratio would be.

This means that the wider the bandwidth is, the quality of the channel can be lower. This would also mean that the system is tolerant to interference.Information can be transmitted even if the quality is below noise floor


WCDMA Basic Characteristics: Spreading the signal done in two phases:

Phase 1 by using spreading codes:In uplink to separate users and control dataIn downlink to separate common and dedicated channels in one cell

Phase 2 by using scrambling codesIn downlink it identifies the cellIn uplink is identifies the user (call)

The radio planner allocates the scrambling codes for the downlink partThe system allocates the spreading codes and the scrambling codes in uplink


WCDMA Basic Characteristics: Spread Spectrum

A signal is spread in the spectrum by artificially increasing the modulation rate (chip rate). By this technique the wider the bandwidth used for transmitting at a given information rate, the lower the required signal to noise ratio. This is the main advantage of spread spectrum techniques. The signal is later despread with the same spreading signal to retrieve the original signal.



A signal is spread in the spectrum by another signal

270 Kbit

GSM

200 KHz

W-CDMA

X Code

5 MHz3.84 Mcps



WBNB

A narrow band signal is spreadwith an orthogonal code.

Code

CodeThe signal is despread with the same spreading code.


WCDMA Basic Characteristics: Processing gain/Spreading Factor

Processing Gain (G) is defined as G )log(10RateServiceRateChip

⋅=

X Code (OVSF)

5 MHz

ProcessingGain

3.84 Mcps


WCDMA Basic Characteristics: Processing gain differ for different services

As can be seen the wider the signal, the lower the power intensity is. This is why the processing gain is lower

W

W

Packet Data user (384 kbps)

R

R

Voice user (12.2 kbps)

Spread wideband signal

Spread wideband signal

Pow

er D

ensi

ty (W

/Hz)

Pow

er D

ensi

ty (W

/Hz)

dBRWG 25)

102.121084.3log(10 3

6

=⋅⋅

⋅==

dBRWG 10)

103841084.3log(10 3

6

=⋅⋅

⋅==


WCDMA Basic Characteristics: Spreading Factor

Spreading factor for different rates are:Higher bit rates = the lower processing gainLower bit rates = the higher processing gain

For 384kbps data rate, the spreading factor is 4For 8kbps data rate, the spreading factor is 128

The higher the bit rate, the more power would be needed to meet the quality requirements

As can be seen from the processing gain calculations, for a high bit rate service, the power needs to be increased.


WCDMA ReceiverRake Receiver:

Due to multi-path environment, the original transmitted signal is reflected on obstacles such as buildings. This makes the signal to take different path to a mobileIf multi-path signals could be combined together in a constructive way, they can enhance the reception of the signal. Rake Receiver has several fingers which receive the different multi-path signals with different delaysEach finger de-spreads the signalAfter de-spreading the signals, they are combined.For uplink purposes the fingers are used for macro-diversity. This is done for soft handover. The output of one finger is not combined and is used for scanning the monitor sets. This finger is known as the “Search Finger”.


WCDMA ReceiverMobiles usually have four fingers. Three for active sets and one for scanning the monitor sets.Node-Bs could have more fingers. Some manufacturers implement 6 fingers in the Node-Bs.


Design ConceptsDesign Concepts


Design Concepts: RF design;

Basically there is no difference between 2G and 3G in terms of RF design methodology.Important to understand that in WCDMA each new site is effectively a new interferer.Important to pay attention how to control the propagation of the sites.Common shared resource in WCDMA is power. Therefore coverage is important. Trade off planning = coverage versus capacityTrade off planning means that if you give too much coverage you take away capacity as you have to use more power


Design Concepts: GSM

Radio channels are isolated from each other.

The power broadcast on one channel will not affect the power required to broadcast others.

The level transmitted by a channel is not so important and can be considered to be constant.

WCDMA Radio channels will interfere with each other.

The more power broadcast on one channel the more noise. The more noise, the more power is required to overcome that noise.The level transmitted on a channel is critical. Too little transmission results in signals not being received, too much transmission results in excessive noise on other channels.



A worst case broadcast can be considered and one can be confident that all other broadcasts will work (BCCH at max all the time).

The power level broadcast on the control channel is constant and isolated from other signals.

WCDMA One must consider all broadcasting channels together since each channel will affect each other.

The power level broadcast depends on the number of channels being broadcast. Each channel needs a certain amount of power to transmit and a certain amount more to cope with the noise from other channels.



Radio reception is considered in terms of the absolute signal level received.

The design need only to ensure that the level received from a channel is above an acceptable minimum level.

An engineer needs to plan the frequencies

WCDMA Radio reception is considered in terms of the received signal level against noise or interference.

The design must ensure that all data channels are received at an exact signal to noise level, no more and no less.

An engineer needs to plan the scrambling codes



Coverage does not vary with the number of channels being used nor on the location of the users of those channels. Service therefore does not vary with the traffic.

A mobile will only connect to one cell at one time. There is no benefit from combining the signal from several connections.

WCDMA Service levels depend on the number of channels present and the locations of users of those channels. Service therefore depends heavily on the traffic load.

A mobile can connect to several cells at the same time. The signal paths are combined to improve. This results in lower power to make the connections, hence less noise.


Design Concepts: Reuse of legacy sites (co-location)

Advantage: cheapDisadvantage: Inflexible design. Same mistakes as in the existing network can occur.Enough space must be available on pylons and floorAvailability of extra Power supply and E1Some high capacity design might not be possible (e.g. 6-sector design on a 3-sector GSM network).


Antenna Installations

DCS 1800

BTS

UMTS

Node-B

X-polar UMTS

antenna

Independent feeders / independent antennas

Shared feeders / Shared antenna

DCS 1800

BTS

UMTS

Node-B

Duplexer Duplexer

DuplexerDuplexer

X-polar Dual Bandantenna

Shared feeders / Independent antennas

Duplexer

Duplexer

DCS 1800

BTS

UMTS

Node-B

Duplexer

Duplexer


Design Concepts: Typical cell sizes

There is no difference from RF point of viewIn WCDMA the effective service area for a certain service shrinks when the load increases (the so called cell breathing). This happens for the shared channels. For common channels, there is no impact on the cell size.

Up to 400mPico cells

Up to 1kmMicro cells

0.5km to 4kmSmall macro cells

1km to 30kmMacro cells

Typical cell radiusCell type


Design Concepts: In GSM the desired signal must be strong enough to override interference. In WCDMA all the cells are transmitting on the same frequency band. The figure of quality is Eb/No and Ec/Io . Ec/Io is the case when other interferer are also taken into consideration. This is indicated by the letter “I”. Right at sector, Ec/Io is ratio of pilot power to total power radiated from that sector.Elsewhere, Ec/Io is ratio of power of particular pilot to total power received from all sources.

e.g. if two sectors have Ec/Io of -5dB, the measured Ec/Io of either of them at the “equal Ec/Io” boundary will be -8dB.


Design Concepts: Cell Breathing

The more load in the system, the more interference will be generated in the system. This will have the effect that the receiver noise floor is higher in a loaded system compared to an unloaded system. Each service requires a certain Ec/IoIn order to keep the Ec/Io requirement the best service area for each cell will be smaller as to this noise raise when the system carries more traffic.


Design Concepts: Different services have different cell sizes

Different data rates, have different Ec/Iorequirements.This means that for a given output power the cell sizes are different for different data ratesThe higher data rate the smaller the cell size is.


Design Concepts: Aim is to contain each sector to its intended coverage areaPoor coverage control leads to:

Access Failures“Slow Handoff” dropped callsReduced capacity

Key metric is Ec/Io (not absolute level)


Design Concepts: Power is the common resource in WCDMA.

Control channels and traffic channels share the same resource i.e. power. If more power is used for control channels, the portion for traffic channels is reduced. Thus capacity is reduced. The coverage for control channels must be higher than traffic channels so that mobiles can decode neighbouring cells before entering a soft handover zone. The broadcast channel containing the cell information has to be decoded before the mobiles enters the coverage area of the cell. This is why it is important to distribute the power in a correctway between the common channels.


Design Concepts: Common channels that need to share the power are:

Synchronization Channel (SCH)Primary Common Control Physical Channel (P-CCPCH)Secondary Common Control Physical Channel carrying the Paging Channel Secondary Common Control Physical Channel carrying the Forward Access ChannelCommon Pilot Channel (CPICH)Acquisition Indication Channel (AICH)Page Indication Channel (PICH)

Typically the CPICH power is defined and the other channels’ powers are set relative to CPICH power


Design Concepts: Rule of thumb:

CPICH power 5%-10% of the total power Usually 30dBm – 33dBm

-8dBAICH

-8dBPICH

-3dBS-SCH

-3dBP-SCH

0dBSCCPCH-2

0dBSCCPCH-1

-5dBPCCPCH

33dBmP-CPICH

Power SettingTransmitted Channel


Design Concepts: It is important to consider the percentage of maximum power of base station used for SCHSCH consists of

Primary SCH (P-SCH) used to find slot synchronizationSecondary SCH (S-SCH) used to find scrambling code and frame synchronization


Design Concepts:Scrambling code

Scrambling code planning in WCDMA is similar to frequency planning for BCCH in GSM. Each cell has its own scrambling code. Total 512 scrambling codes are available. These are in 64 groups (each group containing 8 codes)

CodeGroup 1

Group 0 1 2 … 630 8 16 5041 9 17 5052 10 18 5063 11 19 5074 12 20 5085 13 21 5096 14 22 5107 15 23 511


Design Concepts:Scrambling code need to be selected in optimum way because:

It has a great impact to the cell search algorithmThe call setup/HO performance depends on the reliability of the search procedure in the cell search setupsThere must be large enough separation between two cells using the same scrambling code. A recommended minimum reuse distance of 64 can be used.


Design Concepts:Scrambling code planning is independent for each carrier layer.

The same codes could be used for two carriers. Cell search time increases when the number of neighbours is high e.g. in Urban area where a lot of sites exist. This means that the size of the number of neighbours sets should be large enough to include all useful candidates but as small as possible to maintain fast synchronization process.


Link BudgetLink Budget


Link Budget:Link budget is needed for path loss and cell range calculations before planningThere are a few WCDMA specific parameters:

Processing GainLoad Margin (interference)Power Control headroomSoft Handover Gain

It is a must to consider both of the links when balancing the uplink and downlink service areas.


Uplink Link Budget

Mobiles with data capability might have a higher output power (3GPP TS 25.101)


Link Budget:Required Eb/No means that for some quality target (BLER) a certain average bit-energy over total noise+interference spectral density (Eb/No) is required. The value depends on the service and the MS speed for which the link budget is to be calculated.


Link Budget:The reason why Eb/No requirement is lower for higher bit rates is:

DPDCH and DPCCH are sent together. DPCCH includes the overhead information bits.When sending data, the DPDCH will require higher power. The amount of overhead information does not increase proportionally with information bit rate. As DPDCH will have higher power when sending with higher bit rates, DPCCH will enjoy higher power as well. Therefore lower quality requirement will be put on DPCCH channel. Thus lower Eb/No for higher data rates.


Downlink Link Budget


CPICH Link Budget


Physical, Logical and Transport ChannelsPhysical, Logical and Transport Channels


Logical Channels:

3GPP TS 25.2113GPP TS 25.211


Logical ChannelsBCH Broadcast Channel

Carries system and cell-specific information; always transmitted over the entire cell with a low fixed bit rate

PCH Paging ChannelFor messages to the mobiles in the paging area

FACH Forward Access ChannelCarries control information from base station to mobile in one cell when the system knows the location cell of the mobileMay also carry short user packetsMay be transmitted over whole cell or over a portion using lobe-forming antennas


Logical ChannelsRACH Random Access Channel

Uplink channel used to carry control information from the mobile stationMay also carry short user packetsAlways received from the entire cell

CPCH Common Packet ChannelCarries small and medium-sized packetsA contention-based, random access channel used for transmission of bursty data trafficAssociated with a dedicated channel on the downlink, which provides power control for the uplink CPCH


Logical ChannelsDCH Dedicated Channel

A downlink or uplink channel used to carry user or control information between the network and the UECorresponds to three channels:

DTCH Dedicated Traffic ChannelSDCCH Stand-Alone Dedicated Control ChannelACCH Associated Control Channel

Transmitted over the whole cell or only a part using lobe-forming antennasMay have fast rate changes (even every 10 ms), and fast power control


Transport Channels:Logical channels are mapped onto transport channels


Physical Channels:


Physical ChannelsDPCH - Dedicated Physical Channel

A downlink or uplink dedicated physical channel used to carry user or control information to User Equipment (UE) over an entire or cell or part of the cell that uses beamforming antennas

PRACH - Physical Random Access ChannelA common uplink physical channel used to carry control information or short user packets from the UE

PCPCH - Physical Common Packet ChannelA common uplink physical channel used to carry short and medium-sized user packets. It’s always associated with a downlink channel for power control


Physical ChannelsCPICH - Common Pilot Channel

A fixed-rate downlink physical channel that carries a predefined bit/symbol sequence

P-CCPCH Primary Common Control Physical ChannelA fixed-rate downlink channel used to broadcast system and cell-specific informationThe P-CCPCH is not transmitted during the first 256 chips of each slot (I.e., it maintains a 90% duty cycle)

S-CCPCH Secondary Common Control Physical ChannelA downlink physical channel used to carry the FACH and PCH transport channel


Physical ChannelsSCH Synchronization Channel

A downlink signal used for cell search. The SCH consists of two subchannels, the primary and secondary SCH, which are transmitted during the P-CCPCH idle period

PDSCHA downlink channel used to carry the DSCH transport channel

AICH Acquisition Indicator ChannelA fixed-rate downlink physical channel used to carry access preamble acquisition indicators for the random access procedure


Physical ChannelsAP-AICH Access Preamble Acquisition Indicator Channel

A fixed-rate downlink physical channel used to carry access preamble acquisition indicators of CPCH

PICH Paging Indicator ChannelA fixed-rate downlink physical channel used to carry the paging indicators which disclose the presence of a page message on the PCH

CSICH - CPCH Status Indicator ChannelA fixed-rate downlink channel used to carry CPCH status informationA CSICH is always associated with a physical channel used for transmission of CPCH AP-AICH, and uses the same channelization and scrambling codes


Physical ChannelsCD/CA-ICH Collision-detection/Channel-Assignment Indicator Channel

A fixed-rate common downlink physical channel used to carry CD indicator only if the CA is not active, or a CD/CA indicator at the same time if the CA is active

CDM Continuous Code Division Multiplex Pilot ChannelSimilar to the cdma2000 pilotTwo types of pilot channels are defined:Primary CPICH (P-CPICH)

Transmitted over the entire cellUsed as phase reference for SCH, P-CCPCH, AICH, PICH, and default reference for all other downlink physical channels

Secondary CPICH (S-CPICH)Can be transmitted over part of the cell, not entire cell. May be used as reference for the S-CCPCH and downlink DPCH, or inbeamforming antenna schemes


Radio Radio ResourceResource Management Management


Power ControlPower Control


Power ControlPower control is very important in WCDMA as users are interferer to each other.

Channel #i

Channel #i

User 1

User 2


Power ControlThe aim is to control the transmitted power from the mobiles so that interference is minimizedTwo different types of power control procedures for UL:

Open Loop; at call setupClosed Loop; during the connection

Open Loop power control (UL):The mobile (UE) estimates the access power level by sending a preamble message at an estimated power level. If the Node-B does not respond to the mobile, the mobile waits a certain period of time and retransmits at a higher power level. The mobile continues doing so until it receives a response from the Node-B.


Power ControlClosed Loop power control (UL):

When the connection is established, the power is controlled by the closed loop power control procedure. The RNC sets the target BLER level for the service. From this BLER, it derives a SIR target and sends it to Node-B. The Node-B estimates an UL SIR level and decides if the power of the mobile has to be increased or decreased (this part is called for Inner Loop). This power control is done 1500 times/second to achieve a minimum output power. The RNC calculates the SIR target once every 10ms (or more) and adjusts the SIR target (this part is also called Outer Loop).

DL power control is controlled by the mobile by sending messages to the Node-B (the RNC determining the target BLER and sending it to the mobile).


Power Control:

Open Loop At call setup

RNCRNC

Outer LoopQuality target

Inner LoopDuring a connection


HandoverHandover TypesTypes


Soft Handover (within WCDMA network)Mobile is connected to two cells or more cells from different Node-Bs.

RNCRNC


Softer Handover (within WCDMA network)Mobile is connected to two cells from the same Node-B.

RNCRNC


Hard Handover (within WCDMA network)Mobile makes a handover to another frequency. It is used usually when there is no network support of macro diversity (soft handover).It can also be used to change the mode between FDD and TDD.

RNCRNC


Inter-Radio Access Technology Handover (with other networks)

Handover from WCDMA to another radio system access system such as GSM.

WCDMAWCDMA

GSMGSM


CapacityCapacity


Capacity in WCDMACapacity is tuned mainly by powerCapacity is constrained by the number of active users in a cell and the power allocation strategies.

PBTS = Σ Pi

Pi is the power given to user I at a certain timePBTS is the maximum available power of the Node-B

How to reduce congestion?Could reduce power allocation to all users = power limiting

bad for quality for many usersnot recommended

Better approach: block at certain power threshold (before power limiting)


Capacity in WCDMACapacity is controlled by mainly three different features:

Admission Control which decides whether a connection should be allowed or not. Load Control which takes action when load is increased so that the interference is minimizedPacket Scheduling which controls the handling of the non-real time traffic so that the most optimized way of transferring packets is chosen.


Capacity enhancement6 sectored sites

More carriers than in 3 sectored siteCapacity gain is around 80% capacity (not 100% as inter-sector interference has a negative impact)

Additional CarriersDoubling the amount of carriers with power splitting gives around 60% increased capacity

Increasing powerMore power means more capacity as well

Other none-implemented features


Admission ControlAdmission Control


Admission ControlAdmission Control is a feature that decides whether a request to establish a Radio Resource Connection (RRC) or Radio Access Bearer (RAB) is admitted in the Radio Access Network (RAN) or not. It controls the load in the system. Admission Control is used to maintain stability and the traffic capacity of RAN. The Admission Control algorithm is executed when radio access bearer is setup or the bearer is modified. It takes all kind of handovers into account when calculating the impact.Both uplink and downlink is estimated separately. The inter-cell interference effect is estimated. Bearer is not admitted if the predicted load exceeds a certain thresholds either in uplink or in downlink.


Admission ControlThe traffic can be divided into two groups

Real Time (RT) or non-controllableNon-Real Time (NRT) or controllable

Some portions of capacity must be reserved for the real time traffic for mobility purposes all the time. The proportion between RT and NRT traffic varies all the time. Since it is not enough to divide the load to RT and NRT, one must take into account the interference coming from surrounding traffic. This gives that traffic is divided between controllable and non-controllable traffic.


Admission ControlNon-controllable traffic:

Real time traffic user Other-cell usersNoiseOther NRT users which operate minimum bit rate

Controllable traffic:NRT users

When is an RAB accepted?An RAB is accepted if the estimated non-controllable uplink and downlink load, measured in total received interference power and transmitted carrier power, is kept below the planned load target and the total load below the overload threshold.


Monitoring and Monitoring and OptimizationOptimization


Monitoring an WCDMA networkDrive testing

On street level signal strength and qualityOperational measurements from OMC

Per-sector attempts, blocks, failures, dropped calls etc.

Performance Data from Node-BsTransmit/receive powerUsage and handoff statisticsCarrier Equipment usage

Diagnostic Logs from RNC and Node-BsUse on “as needed” basis


Monitoring an WCDMA networkPre-Commercial; Initial Tuning

Drive Test based methodsPost Commercial; Optimization

Performance Monitoring (identify problem areas):Dropped calls, Access failures,Node-B Performance Data (poor capacity, high handoff)Congestion

Root Cause Analysis (identify solutions):RNC Diagnostic Log analysisDrive TestNode-B Diagnostic Log analysis


ToolsPlanning

Atoll, NetAct or Planet or etcDrive test data collection

TOM or TEMSDedicated phones (usually 2)Scanners

Post processing toolsNIMS PrOptimaACTIX

Performance monitoring toolsNIMS PrOptimaNetAct


Drive TestingWCDMA specific measures to look for:

RSCP for CPICH channel (RSCP = Received Signal Code Power)

Ec/IoScrambling codeNumber of Active SetsNumber of Monitor SetsBLERSignal to Interference ratio (SIR) levelTx power from the mobile (UE)


Initial tuning phasePerform a full network/cluster drive test in an unloaded network (RSCP and Ec/No)Perform dropped call and access failure analysis.Perform the RF coverage analysisOptimize pilot pollution by

Tilting the antennas

Azimuth changes

Change of antennas

Power parameter changes

Tune the neighbour lists


Initial tuning phaseCollect both continuous calls and short calls to get network statistics


Reporting examples:Scanner RSCP sample distribution.

RSCP = Received Signal Code Power = signal strength


Reporting examples :Scanner Ec/No sample distribution.


Reporting examples :Scanner RSCP versus Ec/No sample distribution:


Reporting examples :Problem area definition based on signal strength:

SC17-01

SC17-02

SC17-04

SC17-03

SC17-05 SC17-06

SC17-07

SC17-08

SC17-09


Reporting examples :Problem area definition based on quality:

SC17-01

SC17-02

SC17-04

SC17-03

SC17-05 SC17-06

SC17-07

SC17-08

SC17-09


Reporting examples :Drive test statistics:


Drive Drive TestingTesting Results and Optimisation Results and Optimisation CasesCases


Problem from live network: OvershootingNo antenna optimization possible due to co-location with GSM. Overshooting and dragging the call. Dropped due to bad Ec/No


Problem from live network: Network problem / Synchronization problemMeasurement Report being sent many times but no response from network. Dropped due to bad Ec/No.


Problem from live network: UE Problem.Good RSCP and Ec/Io. UE suddenly dropped the call and went into Idle Mode. After going into idle mode, Master Information Block was showing the PLMN was from another network.


Problem from live network: IMSI Detach from the network.Good RSCP and Ec/Io. Sudden “IMSI DETACH INDICATION” by the network and “RRC Connection Release Complete”.


Problem from live network: Missing neighbours 1/2

No external neighbours defined. 3

4

5 6


Problem from live network: Missing neighbours 2/2


Optimization experiencesInfluence network with RF Design and subsequent antenna changes

Parameter changes are mainly to suit needs of networkUnlike GSM, parameters are rarely used to influence system

everything is co-channel therefore, if signal is present, cannot choose whether to use it or not

Optimizing power allocation to the various channels is crucialPilot Pollution elimination is of great essentialTerminal problems


Optimization scenario in NIMS PrOptima


Optimization Process

MYCOM Practical WCDMA Course

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