06 Training on WCDMA Optimization Cases(Assistant Data Analysis)

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Training on WCDMA Optimization Cases

(Assistant Data Analysis)

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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

� Engineering Parameter 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


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 UE’s data and Scanner’s data.


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� Full layer 3 signaling analysis

Support 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 data and 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 Absenc e

� 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 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

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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 Bar to view the scrambles in UE active set/monitored set.

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Typical Case 2 –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

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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

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

Lst CORRMALGOSWITCH

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 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 Sy stem

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

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Typical Case 4 – Call Drop Difference Caused by Different Versions of Assistan t

Assistant 1.3 processing result

Assistant 1.2 processing

version

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

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Call drop points compared by Assistant

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Typical Case 4 – Call Drop Difference Caused by Diffe rent 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 piont s

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 5 – Missing 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_ActiveSet_Best SC

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?

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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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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 area

Call drop area

� At the call drop spot, the radio environment 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.

UE transmit power is increased before

call drop.

SC192 Ec/IoSC176 Ec/Io

UE TxPWR


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Compare and analyze the test data imported to PROBE an d 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 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.

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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 is good 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, 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

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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 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.

� 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)

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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 is restored to normal operation.



Call drop location

Call drop location

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Signaling retrospective before and after call drop


� L3 signaling flowBefore 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 4º to 9º.

� The pinpoint effect causes the call drop in the fol lowing 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.

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Typical Case 9 – UE Is Abnormal


� At the call drop point, DTI test signal is good. During the moving, the quality 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

� 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

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L3 signaling analysis


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

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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.

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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 to –80 dBm. The pilot pollution 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 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.

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Adjustment and verification

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

Pilot pollution of Huizhou Bridge after the antenna adjustment

Huizhou sector 1 coverage after the antenna adjustment

Xiti road sector 3 coverage after the antenna adjustment

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Typical Case 11 – Neighbor Cell Optimization of Whol e Network

� Assistant provides rich report statistics functions. According to the data collected by the DTI, use the functions of Assistant （dataset）/Analyze Report/WCDMA Scanner NeighborCell 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.

� Neighbor Cell:

� RSCP Threshold� Count Threshold

Only the previous two conditions are met. Assistant configures the neighbors.

Neighbor optimization of whole network through Assista nt

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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 Net work

Neighbor optimization output of whole network through the Assistant

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06 Training on WCDMA Optimization Cases(Assistant Data Analysis)

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