06 Training On Wcdma Optimization Cases(Assistant Data Analysis).Pdf

06 Training on WCDMA Optimization Cases\(Assistant Data Analysis\) 11 1 Training on WCDMA Optimization Cases (Assistant Data Analysis) 22 2 Genex Assistant Introduction Contents Typical Cases Applicat[.]

Training on WCDMA Optimization Cases

(Assistant Data Analysis)

Support the different types of data

source and import format.

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

Support the multi-window bidirectional data cooperation, such as

message, event, map, and diagram.

Provide the automatic

report on the UE’s data

and Scanner’s data

Full layer 3 signaling analysis

Support NAS and layer 3 RRC signaling analysis and the query of signaling contents.

Assistant Technical Characteristics 4

Support the soft handover event by using the SCANNER data

and support the parameter settings.

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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y61891, 2007-6-22

Call Drop Because Soft Handover Algorithm Switch Is OFF

Call drop exists when the CS

services 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 in

the active set is degraded

missing neighbor cells? Abnormal interference?

Single site verification

perspective, the monitored set has samesite 136 and 138

scrambles The neighbors are normal

Choose View -> Properties

Bar-> WCDMA UE

Measurement Bar to view the

scrambles in UE active

set/monitored set

Drop Because Soft Handover Algorithm Switch is OFF

Before the call drop, UE sends 1A event with many 136 and 138 scrambles Check the measurement control message

The intra-frequency measurement cell includes 136 and 138 scramble cells.

Confirming L3 Message

Typical Case 2 – Drop Because Soft Handover Algorithm Switch is OFF

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/Io after the call

is re-set up

Checking the external interference

Call Drop Because Soft Handover Algorithm Switch is OFF

Lst CORRMALG OSWITCH

The network side does not

respond 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

Problem location

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 labeling automatically 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

Difference Caused by Different Versions of Assistant

Typical Case 4 – Call 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 1.2Call 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

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

Analysis of call drop point

left,

are good, the signal in the place where the call drop exists is about -70dBm

inconsistent with DTI Best SC

on the new cell SC485

DTI_RSCP

Before the call drop, the

UE does not hand over to SC485 cell in time, the call drop is caused Is the call drop caused by the missing neighbor cells?

Typical Case 5 – Missing Neighbor Cell

Checking neighbors

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

control message includes the target

cell before the call drop

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

Typical Case 6 – Handover Failure

Call drop area drop Call

area

is 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

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

Typical Case 6 – Handover Failure

Process before and after call drop when PROBE collects L3 Message

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

RNC L3 Message process analysis

Active set is updated Adding the PSC176 cell is required

Active set is updated Deleting the PSC176 cell is required

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

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:

Typical Case 6 – Handover Failure

Through the RTWP tracing, the RTWP

of the cell is about –105 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

Problem location and troubleshooting

Troubleshooting

Change the handover radius to 0

Re-perform the test and the call

drop disappears

Call drop point analysis

is good but the signal of serving cell received by UE is degraded dramatically

Active set quality is bad

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, the

RNC 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 RNC

thinks 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

Problem location and troubleshooting

Analysis of call drop reasons

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

Ec/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

over to the target cell in advance to avoid the handover failure

corner and to eliminate the handover risks at the corner

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)

Before the call drop, the UE

resides on the cell SC16

temporarily After the call

drop, the UE camps on the

cell SC18

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 is

restored to normal operation

Analysis of call drop point

Call drop location

Call drop location

Signaling retrospective before and after call drop

Typical Case 8 – Pinpoint Effect

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

Problem location and troubleshooting

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 4º to 9º

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

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

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

Typical Case 9 – UE Is Abnormal

Analysis of call drop point

of 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

of serving cell and neighbor The signals in the Monitor Set are better than that in the Active Set

DTI

L3 signaling analysis

UE does not report and receive the message for about 40 seconds.

Problem location and troubleshooting

Typical Case 9 – UE Is Abnormal

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

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

Check the WCDMA DTI

Coverage Bar and find nine

scramble cell coverage signals

The signal strength ranges from

–70 dBm to –80 dBm The pilot

pollution is serious and the Ec/Io

is degraded dramatically

Problem analysis

Analysis process 1

Typical Case 10 – Pilot Pollution

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

Analysis process 2

impact on the bridge of overshooting

coverage

Due to the impact of water

reflection, the cells in red circle

cover a far distance and result in

the interference to the bridge

Adjust the antenna azimuth and tilt

to optimize the cell coverage area

Typical Case 10 – Pilot Pollution

Adjustment and verification

Huizhou sector 1 coverage after the antenna adjustment

Xiti road sector 3 coverage after the antenna adjustment

Assistant provides rich report statistics functions According to the data collected by the DTI,

Analysis According to the predefined RSCP and COUNT thresholds, analyze automatically the

neighbors based on the DIT test data In conjunction with the actual neighbor list, obtain the

possible missing neighbor cells

Only the previous two conditions are

met Assistant configures the neighbors

Neighbor optimization of whole network through Assistant