Training on WCDMA Optimization Cases (Assistant Data Analysis)(2)

7/28/2019 Training on WCDMA Optimization Cases (Assistant Data Analysis)(2)

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Training on WCDMA Optimization Cases

(Assistant Data Analysis)


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Notes on Use of Training Cases

Thank you

1. This slide is for internal training use only.

2. For any technical problems, fill in theGCRMS problem sheet to modify the them

in time.


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Genex Assistant Introduction

Contents

Typical Cases Application


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Support the different types of data

source and import format. Genex Probe

Agilent E7476A

Agilent E6474A

Huawei RNC

EngineeringParameter

Table

Neighbor

configuration data

Support the combined analysis of

uplink and downlink dataAnalyze the signaling of both UE and RNC to

realize simultaneous analysis of uplink and

downlink data.

Assistant Technical Characteristics 1


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Support multiple types of data

display modes. Support Sheet/Map/Chart/Caky/

Histogram display modes.

Support the import of data

displayed in multiple types, such

as BMP/JPG/GIF/PNG images, txt

documents, and Excel.

Image window

Map window

Assistant Technical Characteristics2

Tab window


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Support the multi-window bidirectional data cooperation, such as

message, event, map, and diagram.

Provide the automatic

report on the UEs data

and Scanners data.

Assistant Technical Characteristics3


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Full layer 3 signaling analysisSupport NAS and layer 3 RRC signaling analysis and the query of signaling

contents.



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Support the soft handover event by using the SCANNER dataand support the parameter settings.



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Genex Assistant Introduction

Contents

Typical Cases Application


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Type Case 1-- Assistant Prompts Genex License Absence

Start the Assistant software. The system prompts no license.

Find that the hardware dongle is operational. Re-install the Assistant

software. The problem persists.

Check the installation program and find no Sentinel System Drive software. Install the

software or un-install the Genex Shared. The problem is cleared.

Installing Assistant


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Typical Case 2

Call Drop Because Soft Handover Algorithm Switch Is OFF

Call drop exists when the CSservices are verified. Check the

DTI scanning RSCP coverage

before and after call drop and the

Ec/Io distribution in the UE active

Strong coverage

Before call drop, the Ec/Io inthe active set is degraded.

missing neighbor

cells? Abnormal

interference?

Single site verification


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Typical Case 2 Call

Drop Because Soft Handover Algorithm Switch is OFF

Checking the neighbor

From the UE

measurement data

perspective, the

monitored set has

samesite 136 and 138

scrambles. The

neighbors are normal.

Choose View -> Properties

Bar-> WCDMA UE

Measurement Barto view the

scrambles in UE active

set/monitored set.


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Typical Case 2


Before the call drop, UE sends 1A

event with many 136 and 138

scrambles. Check themeasurement control message.

The intra-frequency measurement

cell includes 136 and 138

scramble cells.

Confirming L3 Message


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Typical Case 2


Cell update after

the call drop

The Ec/Io is good after the call is re-originated. The problem is not

caused by the external interference.

Good Ce/Ioafter the callis re-set up

Checking the external interference


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Typical Case 2

Call Drop Because Soft Handover Algorithm Switch is OFF

Lst

CORRMAL

GOSWITCH

The network side does notrespond to the 1A event reported

through the measurement report,

or the network problem settings

are incorrect.

If the soft handover switch is

off, open the switch and

perform the test verification.

The problem is cleared.

The soft handover switch is off. The problem may

be caused by normal reasons, but the problem

indicates that the test is not well prepared. The

communications with the related engineers are not

performed well before the test.

Problem location


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Typical Case 3 Coverage

Abnormal Caused by Inverse Connection of Antenna System

Automatically

label the data at

the diagram layer

After synchronizing the BTS color and labelingautomatically the data at the diagram layer

Within the coverage range of SC130, the

actual range is SC128.

Within the coverage of SC128, the actual

range is SC130.

The problems found during the single site verification are obvious

and easy to process. However, the engineers must be careful and

conform to the specifications during the test optimization.

Reverse connection of antenna system

Synchronize the

BTS color


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Typical Case 4Call Drop

Difference Caused by Different Versions of Assistant

Assistant 1.3

processing result

Assistant 1.2

processing version

Are the time, longitude, and latitude of call drop point inconsistent?

???

Call drop points compared by Assistant


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Typical Case 4Call Drop Difference Caused by Different

Versions of Assistant

Definition of Assistant 1.3 call drop point:

1. Receive a message of CC Disconnect, CC Release

Complete and CC Release and the release cause

value is neither Normal Clearing nor Normal

Unspecified.

2. Receive the RRC release message and the release

cause is neither Normal nor user inactivity. The

RRC release message is not received and the UE

is transited from connected state (CELL_FACH and

CELL_DCH) to idle state ( IDLE ).

3. UE receives the system information in the

connected state and does not receive RB Recfg,

Trch Recfg and PhyCH Recfg before receiving the

system information. The UE must be transited from

CELL_DCH to CELL_FACH. Within the specified

time T1, the UE does not originate the CELL

Update (re-setup). Within the specified time T1, the

UE originates CELL Update but fails for N times of

retransmissions.

Call drop point of Assistant 1.2

Call drop point of Assistant 1.3

With the Assistant 1.2 version, in the connected state, if

the UE receives the system information, it is regarded as

call drop. With Assistant 1.3 version, if the Cell Update

succeeds within T1, it is not regarded as call drop. If the

Cell Update fails, it is regarded as call drop.

Definition of Assistant 1.2 call drop point:

1. UE receives any system information in the

connected state.

2. Receive RRC Release message and the

release cause value is Not Normal.

3. Receive a messages of CC Disconnect,

CC Release Complete, and CC Release,

and the release cause value is Not Normal

Clearing or Not Normal Unspecified.

Comparison between the definitions of call drop pionts

Definition of

Assistant 1.2

Call drop point

Definition of

Assistant 1.3

Call drop

point

Comparison

between the

locations of call

drop points


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Typical Case 5Missing Neighbor Cell

On the way to Zhongkai, the call drop exists in the place from PSC=504 to PSC=485.

Analysis of call drop point

According to the diagram in the

left,

The signals in the test area

are good, the signal in the

place where the call drop

exists is about -70dBm.

UE_ActiveSet_Best SC is

inconsistent with DTI Best SC.

After the call drop, UE resides

on the new cell SC485.

DTI_RSCP

DTI_Best SC

UE_ActiveSe

t_Best SC

Before the call drop, the

UE does not hand over toSC485 cell in time, the call

drop is caused. Is the call

drop caused by the

missing neighbor cells?


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Typical Case 5 Missing Neighbor Cell

Checking neighbors

Neighbor check method 1 Neighbor check method 2

Check whether UE_ Monitor Set has the target cell.Check whether the intra-frequency

measurement cell of measurement

control message includes the target

cell before the call drop.


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Typical Case 5 Missing Neighbor Cell

Problem location and troubleshooting

Problem location

It is a typical case of call drop caused by the missing neighbor cell.

Call drop caused by missing neighbor cell is accompanied with two types of

phenomena:

1. Before the call drop, the best service cell measured by the SCANNER is inconsistent

with actual best cell measured by UE. The best service cell quality of SCANNER is

better than that of UE.2. After the call drop, the UE camps on the new cell.

Check the neighbor through the following two methods of Assistant:

1. Check whether the Monitor Set of UE includes the target cell.

2. Check the latest measurement control message before the call drop, and analyze

whether the intra-frequency measurement cell list includes the target cell.

Troubleshooting

Configure the SC504 cell and SC485 cell as neighbor

cell for each other.


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Typical Case 6 Handover Failure

Call

drop

areaCall

drop

area

At the call drop spot, the radio environmentis good. Through the DTI test, before and

after the call drop, Ec/Io is good and RSCP

is also good. In the call drop area, the call

drop occurs during each drive test and the

call drop spot is similar.

UE transmitpower is

increased beforecall drop.

SC192 Ec/IoSC176 Ec/Io

UE TxPWR



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Compare and analyze the test data imported to PROBE and RNC

Data alignment method 1: Define

the time offset of RNC data and

Probe data to align the data.

Data alignment method 2: Search the

time corresponding to the key

signaling to align the data.


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Process before and after call drop when PROBE collects L3 Message

The UE reports the event 1A of PSC176, and then RNC sends the active set update

message and adds PSC176 to active set. The UE reports the event 1D of PSC176 cell,

event 1B of PSC192 cell, and then RNC deletes the measurement control. The UE reports

the continuously two 1B of 192, and then the RNC delivers the active set update message

but deletes the PSC176 cell.


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RNC L3 Message process analysis


Call drop

Active set is updated. Adding the PSC176 cell is required

Active set is updated. Deleting the PSC176 cell is required.

Analyze the signaling between two ASs, and

find that the time difference between two ASs

is 11s. During the time difference, the UE does

not receive the RL Restore message.

According to the RNC configuration, if a radio

link is added, the UE does not receive the RL

Restore message reported by NodeB within 11

seconds, the uplink is synchronized. It is

required to delete the newly added radio link.

The link quality of cell 192 is degraded, and the

call drop occurs.


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The newly added radio link is not synchronized, and ASU is delivered to delete the scrambles of

cell 176 from the active set. The quality of scrambles in cell 192 is bad, so the call drop occurs.

The uplink asynchronization may be caused by the following:

Uplink interference --- check the RTWP of cell 176

Parameter setting problem - LST LOCELL


Through the RTWP tracing, the RTWP

of the cell is about105 dBm.

Check the cell handover radius and find

that the inner diameter of handover

radius is 5000. The configuration is

abnormal. It indicates that UE cannot

perform the handover within 5000 m.

The parameter is set to 0 m by default.


Troubleshooting

Change the handover radius to 0.

Re-perform the test and the call

drop disappears.


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Typical Case 7 Turning Corner Effect

Call drop point analysis

In the boundary of A and B, the call drop occurs. At the call drop point, the DTI test signal isgood but the signal of serving cell received by UE is degraded dramatically.

Active set quality is bad.

Monitor set quality is good

SC304

in AS

SC298

in MS

SC298

in AS


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L3 signaling analysis

UE_L3 signaling

RNC_L3 signaling

Before the call drop, the UE sends

the measurement report that includes

event 1a and 1d of SC298 cell. The

RNC receives the measurement

report and notifies the NodeB to

establish a link to complete the

preparations for 1a event. Then, theRNC sends a RRC ACTIVE SET

UPDAT message to the UE.

According to L3 message at UE side,

the UE does not receive correctly the

ACTIVE SET UPDATE message.

After five seconds, the RNC does not

receive the Active Set Update

Complete message of UE, the RNCthinks that the call drop occurs. Then,

the RNC sends a

RANAP_IU_RELEASE_REQUEST to

the CN to release the resources.

1a and 1d event of sc298 cell

Request for UE active set update


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Analysis of call drop reasons

When the call drop occurs at the corner of the road, due to the blocking of buildings, the

signal quality of original cell is degraded fast. The UE sends 1A event of SC298 cell, but theEc/Io of original cell is deteriorated, the UE does not receive the RRC ACTIVE SET UPDATE

message delivered by the RNC downlink. As a result, the soft handover cannot complete

normally and the call drop occurs.

Troubleshooting

If the turning corner effect causes the handover delay and the call drop occurs, the

characteristics are that the signals of original cell at the corner are degraded fast and the

handover process cannot complete normally. The optimization aims to start the handover in

advance or avoid the handover at the turning corner.

Adjust the CIO offset of target cell and improve the handover priority of target cell. Hand

over to the target cell in advance to avoid the handover failure. Adjust the antenna system so that a sector covers the corner to meet the coverage at the

corner and to eliminate the handover risks at the corner.

Adjust the 1a event threshold and hysteresis to ensure the 1a event occurs easier.


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On the XX road, the call drop occurs. At the call drop point, the signal is good.

Typical Case 8 Pinpoint Effect

Description of call drop point

Scramble distribution (UE) Ec/Io distribution (UE)

C ff


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Before the call drop, the UE

resides on the cell SC16

temporarily. After the call

drop, the UE camps on the

cell SC18.

From the perspective of Ec/Io

quality of UE active set

before and after the call drop,

before the call drop, the Ec/Io

is degraded fast. After the

call drop, the Ec/Io isrestored to normal operation.



Call drop location

Call drop

location


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Signaling retrospective before and after call drop


L3 signaling flow

Before the call drop, the UE sends 1a event

measurement reports of cells SC9, SC18 and

SC17. The RNC correctly receives the

measurement reports and notifies NodeB to

prepare for the resources. And then, the RNC

originates an Active Set Update message to the

UE. If the RNC does not receive Active Set

Update Complete message from the UE within

five seconds, release the IU. The call drop .


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Cause analysis

The rear lobe of cell SC16 forms the pinpoint effect. After the UE camps on the cell SC16, the

signal quality is degraded. As a result, the UE cannot receive the Active Set Update message

delivered by the RNC and the call drop occurs.

Measures

The down tilt of cell SC16 is adjusted from 4 to 9.

The pinpoint effect causes the call drop in the following conditions:

If the pinpoint duration is short and cannot meet the handover condition, and the call drop does

not occur. However, the QoS is degraded. For example, the downlink generates too high BLER.

If the pinpoint duration is short, and the handover conditions are strict, the result is that before

the handover occurs, the downlink signal is too bad and the signaling or service RB is reset. And

then, the call drop occurs.

If the target cell has the handover triggered, the signal of original cell may be too bad and the UE

cannot receive the Active Set Update message, and the call drop occurs.

If the target cell completes the handover and becomes the cell in the active set, the pinpoint

effect disappears within short time. The cell exits from the active set after a handover. This

process also may result in the call drop.

T i l C 9 UE I Ab l


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Typical Case 9 UE Is Abnormal


At the call drop point, DTI test signal is good. During the moving, the qualityof UE active set cell is degraded and the no handover events occur before

the call drop. Check the neighbor and settings of soft handover parameters.

Active

set

Monitor

set

UE can correct measure the signals

of serving cell and neighbor. The

signals in the Monitor Set are better

than that in the Active Set.

DTI

T i l C 9 UE I Ab l


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L3 signaling analysis


UE does not report and receive the

message for about 40 seconds.

T i l C 9 UE I Ab l


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Analysis of call drop reasons

UE originates calls in the cell SC369. During the moving, UE measures that the Ec/Io of

neighbor cell is better than that of active set cell SC369 and 1A event trigger conditions

of soft handover are met, but the UE does not send the measurement report normally.

The signals of cell SC369 are degraded continuously and the UE cannot demodulate

the downlink signals. The UE sends CELL UPDATE message but the network side does

not respond to the CELL UPDATE message. The call drop occurs.

Troubleshooting

This call drop occurs because the UE does not send the measurement report normally.

It is hard to locate the reason. In actual operations, we should avoid the test problems

caused by the abnormal UE. For example, replace the test UE.

T i l C 10 Pil t P ll ti


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On a bridge, the signals from the sites along the river are strong and the pilot pollution is serious.

As shown in the following diagram, the continuous pilot pollution points exist in the area.

Typical Case 10 Pilot Pollution

Check the WCDMA DTI

Coverage Bar and find nine

scramble cell coverage signals.

The signal strength ranges from

70 dBm to80 dBm. The pilotpollution is serious and the Ec/Io

is degraded dramatically.

Problem analysis



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Analysis process 1


According to the geographic distribution, judge preliminarily the primary coverage cells.

After the test, perform the site survey to determine the primary coverage cells.

Cell SC224 can continuously cover the

bridge but the far end signals are weak.

The site survey finds that the cells SC41 and

SC42 are blocked by the high buildings, so

the cells cannot effectively cover the bridge.



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Analysis process 2

Adjust the antenna to reduce the

impact on the bridge of overshooting

coverage.

Due to the impact of water

reflection, the cells in red circlecover a far distance and result in

the interference to the bridge.

Adjust the antenna azimuth and tilt

to optimize the cell coverage area.



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Adjustment and verification

Antenna adjustment:The antenna tilt of Huizhou sector A is adjusted from 10 to 7 .The antenna tilt of Xiti road sector A is adjusted from 9 to 11 .The antenna tilt of Xiti road sector C is adjusted from 7 to 10 .The antenna tilt of Shuidongjie sector C is adjusted from9 to 11 .The antenna tilt of Golden world sector C is adjustedfrom 5 to 9 .

Pilot

pollution of

Huizhou

Bridge after

the antenna

adjustment

Huizhou

sector 1

coverage

after theantenna

adjustment

Xiti road

sector 3

coverage

after the

antenna

adjustment


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T i l C 11 N i hb O ti i ti f Wh l N t k


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Statistics report Introduction :configuration page of DTI data parameters

Scanner Statistic: DTI collection data statistics

Scanner Result: analyze the neighbors according to DTI collection data

and parameter threshold.

Imported Config: imported neighbor configuration data

Scanner vs Config: comparison between DTI analysis data and the

neighbor configuration data

Typical Case 11 Neighbor Optimization of Whole Network

Neighbor optimization output of whole network through the Assistant


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Training on WCDMA Optimization Cases (Assistant Data Analysis)(2)

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