UMTS Troubleshooting 18-10-03

11,60 2,20 7,002, 40 7,80

UMTS Trouble Shooting

18. October 2003

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1) Drop due to missing Neighbor

TEMS log shows that signal is going down. RSCP and Ec/No is weak, RSSI is high Mobile is changing to idle mode.

TEMS log and scanner information showing different SC. After Cell Reselection Ec/No situation is ok. See next pages for typical screen shot.

Add missing neighbor

Symptoms

Reason & Solution

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1) 1 Drop due to missing Neighbor - TEMS

Symptoms

1 bad Ec/No

2 transition to Idle

Mode

3 weak RSCP

4 strong RSSI

5 discrepancy

betw. Scan & Ue

6 low SIR

7 high BLER

8 strong Ec/No

after Cell

Reselection The call drops because the Ec/No is too weak, but after Cell Reselection, the Ec/No of a

different Pilot is very good drop like in GSM !

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2) Drop due to high RTWP

TEMS log shows that RF situation is good. No Pilot Pollution Low Ue Tx Power Call is dropped because RNC request Iu release with command

„IU release request – Utran generated reason“ RNC sendet an UE „RRConnction release-unspecified“ K1297 Iub traces shows in Common Measurement a high value

(>70) for RTWP.

The high RTWP values represents a very high cell load for the nodeB, thus the admission and congestion control are not accepting call setup or call is very likely to be dropped after HO.

Correction of Duamco Settings to right attenuation is solves problem.

Symptoms

Reason & Solution

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2) 1 Drop due to high RTWP (TEMS)

Symptoms

1 good Ec/No

2 good RSCP

3 no Pilot Pollution

4 low Ue TxPower

5 good SIR

6 low BLER

7 dl RRC Connection

Release

with Cause

„unspecified“

Note: there is a difference in time between TEMS Scanner and TEMS Ue

in measuring the Scrambling Codes of the Pilots

The Call drops because the RNC requests an Iu-Release due to „UTRAN generated reasons“

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2) 2 Drop due to high RTWP (K1297 Call Trace )

Long Time From 2. MSG 3. MSG 4. MSG Procedure Code 6. MSG radioNetwork14:39:40,684,298 RNC SD RL DT1 id-Iu-ReleaseRequest release-due-to-utran-generated-reason14:39:40,684,379 UMSC SD RL DT1 id-Iu-Release release-due-to-utran-generated-reason14:39:40,691,612 Node-B #3 (DCH #1 UL) FP DATA DCH14:39:40,691,612 Node-B #3 (DCH #1 UL) AM DATA DCH uplinkDirectTransfer IDRES14:39:40,724,197 UMSC SD RL DT1 id-DirectTransfer RELCMP14:39:40,741,844 RNC SD RL DT1 id-ErrorIndication14:39:40,792,770 Node-B #3 (DCH #1 DL) FP DATA DCH14:39:41,272,658 Node-B #3 (DCH #1 DL) FP DATA DCH14:39:41,272,658 Node-B #3 (DCH #1 DL) UM DATA DCH rrcConnectionRelease cause = unspecified14:39:41,491,366 Node-B #3 (DCH #1 UL) FP DATA DCH14:39:41,491,366 Node-B #3 (DCH #1 UL) UM DATA DCH rrcConnectionReleaseComplete14:39:41,574,742 NBAP UL SD initiatingMessage id-commonMeasurement14:39:41,582,126 NBAP UL SD initiatingMessage id-commonMeasurement14:39:41,637,598 NBAP DL SD initiatingMessage id-radioLinkDeletion14:39:41,669,244 NBAP UL SD succesfulOutcome id-radioLinkDeletion14:39:41,682,452 ALCAP DL SD REL14:39:41,691,502 ALCAP UL SD RLC14:39:42,221,836 RNC SD RL DT1 id-Iu-Release14:39:42,279,628 UMSC SD RL RLSD14:39:42,291,834 RNC SD RL RLC

14:39:44,950,269 C0 RACH UL FP DATA RACH14:39:44,950,269 C0 RACH UL TM DATA RACH rrcConnectionRequest14:39:44,964,028 NBAP UL SD initiatingMessage id-commonMeasurement14:39:44,971,650 NBAP UL SD initiatingMessage id-commonMeasurement14:39:44,993,878 C0 FACH1 DL FP DATA FACH14:39:44,993,878 C0 FACH1 DL UM DATA FACH rrcConnectionReject cause = congestion

DUAMCO-setting: TMAgain – FeederLoss – DUAMCOattenuation = 0dB

Page 7

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3) Call Rejection due to Congestion – high RTWP

TEMS log shows that RF situation is good. No Pilot Pollution Low Ue Tx Power Call is Rejected with reason „Congestion“. K1297 Iub traces show in Common Measurement a high value

(>70 > -105dBm) for RTWP.

The high RTWP values represent a very high cell load for the nodeB, thus the admission and congestion control are not accepting HO or call setup. Even worse, the existing call(s) will be terminated if set so in the RNC database

Correction of Duamco Settings to right attenuation.

Symptoms

Reason & Solution

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3) 1 Call Rejection due to Congestion (TEMS)

After the drop, a new call attempt is rejected by RNC with Cause „Congestion“

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3) 2 Call rejection due to Congestion (K1297 Trace )

New call is rejected by the RNC with cause Congestion. This irrational behavior of the RNC can

be explained by the Congestion Control Algorithm which kicks in when RTWP is high and that

is the case if the TMAgain is not compensated by the FeederLoss and Duamco.

Long Time From 2. MSG 3. MSG 4. MSG Procedure Code 6. MSG radioNetwork14:39:40,684,298 RNC SD RL DT1 id-Iu-ReleaseRequest release-due-to-utran-generated-reason14:39:40,684,379 UMSC SD RL DT1 id-Iu-Release release-due-to-utran-generated-reason14:39:40,691,612 Node-B #3 (DCH #1 UL) FP DATA DCH14:39:40,691,612 Node-B #3 (DCH #1 UL) AM DATA DCH uplinkDirectTransfer IDRES14:39:40,724,197 UMSC SD RL DT1 id-DirectTransfer RELCMP14:39:40,741,844 RNC SD RL DT1 id-ErrorIndication14:39:40,792,770 Node-B #3 (DCH #1 DL) FP DATA DCH14:39:41,272,658 Node-B #3 (DCH #1 DL) FP DATA DCH14:39:41,272,658 Node-B #3 (DCH #1 DL) UM DATA DCH rrcConnectionRelease cause = unspecified14:39:41,491,366 Node-B #3 (DCH #1 UL) FP DATA DCH14:39:41,491,366 Node-B #3 (DCH #1 UL) UM DATA DCH rrcConnectionReleaseComplete14:39:41,574,742 NBAP UL SD initiatingMessage id-commonMeasurement14:39:41,582,126 NBAP UL SD initiatingMessage id-commonMeasurement14:39:41,637,598 NBAP DL SD initiatingMessage id-radioLinkDeletion14:39:41,669,244 NBAP UL SD succesfulOutcome id-radioLinkDeletion14:39:41,682,452 ALCAP DL SD REL14:39:41,691,502 ALCAP UL SD RLC14:39:42,221,836 RNC SD RL DT1 id-Iu-Release14:39:42,279,628 UMSC SD RL RLSD14:39:42,291,834 RNC SD RL RLC

14:39:44,950,269 C0 RACH UL FP DATA RACH14:39:44,950,269 C0 RACH UL TM DATA RACH rrcConnectionRequest14:39:44,964,028 NBAP UL SD initiatingMessage id-commonMeasurement14:39:44,971,650 NBAP UL SD initiatingMessage id-commonMeasurement14:39:44,993,878 C0 FACH1 DL FP DATA FACH14:39:44,993,878 C0 FACH1 DL UM DATA FACH rrcConnectionReject cause = congestion

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4) Drop due to Mobile

TEMS log shows that RF situation is good. No Pilot Pollution Low Ue Tx Power No RRC Release command received from UTRAN See next pages for typical screen shot Mobile is changing to idle mode without any motivation.

Must be a problem from mobile. (Qualcomm) Since Motorola Mobiles are available for TEMS, those Qualcomm

problems shall not be considered any longer. (VDF Topphofen)

Symptoms

Reason & Solution

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4) 1 Drop due to Mobile – TEMS trace

The call drops although the RF-conditions are perferct – a second Ue

in parallel does not drop!

Symptoms

1 good or excellent RF

conditions

2 good SIR

3 low BLER

4 no Pilot Pollution

5 no dl RRC Connection

Release

6 transition to Idle Mode

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5) Missing Radio Bearer Setup

TEMS log shows that RF situation is good. No Pilot Pollution Ue Tx Power increased No RRC Connection Release command received. See next pages for typical screen shot Mobile is changing to idle mode without any motivation.

Possible reasons Downlink Layer 2 RLC errors or synchronisation problems on

Layer 1 Other UTRAN error (e.g. ALCAP Problem between MSC &

RNC). K1297 traces from Iub and Iu Interface necessary.

Symptoms

Reason & Solution

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5) Missing Radio Bearer Setup - Call Setup in TEMS

During Call Setup the Ue requests ActiveSet Update and goes into Soft-HO

Transition to

Idle Mode

Symptoms

1 Ue in SHO

2 Good Ec/Io

3 medium RSCP

4 Good SIR

Before Failure:

5 High TxPower

6 increased BLER

7 low SIR

Normal

Call

Setup

Page 14

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5) Missing Radio Bearer Setup L3 messages

Normal

Call Setup

Procedure

ActiveSet

Update

during call

setupTransition to Idle Mode

After ActiveSet Update Complete no Measurement Control can be received from

the UTRAN no Radio Bearer Setup

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5) Missing Radio Bearer Setup – CalI Setup IMSI trace

Mes

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Prim

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Scram

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Code

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16:00:39 R RRC DCCH MeasurementReport [e1a[0]] [372, 291, 155, 162, 291] 16:00:39 R RRC DCCH SecurityModeComplete

16:00:39 S RANAP SecurityModeComplete

16:00:40 S RNSAP RadioLinkSetupRequestFDD

16:00:40 R RANAP DirectTransfer [Identity Request]

16:00:40 S RRC DCCH DownlinkDirectTransfer [Identity Request]

16:00:40 R RNSAP RadioLinkSetupResponseFDD

16:00:40 S ALCAP ERQ - Establish Request

16:00:40 R ALCAP ECF - Establish Confirm

16:00:40 S RNSAP DedicatedMeasurementInitiationRequest

16:00:40 R RNSAP RadioLinkRestoreIndication

16:00:40 R RNSAP DedicatedMeasurementInitiationResponse

16:00:40 S RNSAP DedicatedMeasurementInitiationRequest

16:00:40 R RNSAP DedicatedMeasurementInitiationResponse

16:00:40 R RRC DCCH UplinkDirectTransfer [Setup]

16:00:40 S RANAP DirectTransfer [Setup]

16:00:40 R RRC DCCH UplinkDirectTransfer [Identity Response]

16:00:40 S RANAP DirectTransfer [Identity Response]

16:00:40 R RANAP DirectTransfer [Call Proceeding]

16:00:40 S RRC DCCH DownlinkDirectTransfer [Call Proceeding]

16:00:40 R RNSAP DedicatedMeasurementReport [55]

16:00:40 R RANAP DirectTransfer [Facility]

16:00:40 R RANAP RAB-AssignmentRequest

16:00:40 S RRC DCCH DownlinkDirectTransfer [Facility]

16:00:40 S RRC DCCH ActiveSetUpdate [291] 16:00:40 R RRC DCCH MeasurementReport [e1a[0]] [372, 291, 162, 155, 291] 16:00:40 R RRC DCCH ActiveSetUpdateComplete

16:00:40 S RRC DCCH MeasurementControl [459, 299] 16:00:40 S ALCAP ERQ - Establish Request

Ue requests ActiveSet Update and

goes into Soft Handover mode

while Radio Bearer Assignment

Page 16

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5 Missing Radio Bearer – Uplink Synchronisation error


16:00:41 S NBAP RadioLinkReconfigurationPrepareFDD

16:00:41 R NBAP RadioLinkReconfigurationReady

16:00:41 S RNSAP RadioLinkReconfigurationPrepareFDD

16:00:41 R RNSAP RadioLinkReconfigurationReadyFDD





16:00:41 S RNSAP RadioLinkReconfigurationCommit

16:00:41 S NBAP RadioLinkReconfigurationCommit

16:00:41 S RRC DCCH RadioBearerSetup

16:00:42 R NBAP DedicatedMeasurementReport [75]





16:00:45 R RNSAP RadioLinkFailureIndication [synchronisation-failure[11]]




16:00:53 R NBAP RadioLinkFailureIndication [synchronisation-failure[10]]

16:00:53 S RANAP RAB-AssignmentResponse [radio-connection-with-UE-Lost[46]]

16:00:53 S RRC DCCH RRCConnectionRelease [normalEvent[0]]

16:00:53 R RANAP Iu-ReleaseCommand

16:00:55 R ALCAP REL - Release Request

16:00:55 R ALCAP REL - Release Request

16:00:55 S ALCAP RLC - Release Confirm

16:00:55 S ALCAP RLC - Release Confirm





16:01:08 S RANAP ErrorIndication [message-not-compatible-with-receiver-state[99]]

Mes

sage

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Tim

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Proto

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SIRtra

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CodeP

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radio

Networ

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Cause

relea

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Cau

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Radio Bearer Setup is sent from RNC

to NodeB but cannot be received by

Ue

MSC sends Iu-Release Comand

SIR error increases to maximum Layer

1 problem on Uplink

Page 17

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5) Missing Radio Bearer – Protocol Errors 1


















16:01:39 S RRC DCCH SecurityModeCommand

16:01:39 S NBAP DedicatedMeasurementInitiationRequest

16:01:39 R NBAP DedicatedMeasurementInitiationResponse





16:01:39 R RRC DCCH SecurityModeComplete

16:01:39 S RANAP SecurityModeComplete

16:01:39 R RRC DCCH InitialDirectTransfer [Location Updating Request]

16:01:39 S RANAP Iu-ReleaseRequest [release-due-to-utran-generated-reason[15]]

16:01:39 R RANAP DirectTransfer [Routing area update accept]

16:01:39 S RRC DCCH DownlinkDirectTransfer [Routing area update accept]





16:01:40 R RRC DCCH MeasurementReport

16:01:40 R RRC DCCH UplinkDirectTransfer [Routing area update complete]

16:01:40 S RRC DCCH RRCConnectionRelease [normalEvent[0]]

16:01:40 R RRC DCCH RRCConnectionReleaseComplete

16:01:40 S NBAP RadioLinkDeletionRequest

16:01:40 R NBAP RadioLinkDeletionResponse

16:01:40 S ALCAP REL - Release Request

16:01:40 R ALCAP RLC - Release Confirm

16:01:41 S RANAP Iu-ReleaseComplete

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5) Missing Radio Bearer – Protocol Errors 2

Wed Sep 03 16:00:45 CEST 2003Receive RNSAP RadioLinkFailureIndication [synchronisation-failure[11]]Wed Sep 03 16:00:49 CEST 2003Receive NBAP DedicatedMeasurementReportWed Sep 03 16:00:49 CEST 2003Receive NBAP DedicatedMeasurementReportWed Sep 03 16:00:49 CEST 2003Receive NBAP DedicatedMeasurementReportWed Sep 03 16:00:53 CEST 2003Receive NBAP RadioLinkFailureIndication [synchronisation-failure[10]]Wed Sep 03 16:00:53 CEST 2003Send RANAP RAB-AssignmentResponse [radio-connection-with-UE-Lost[46]]Wed Sep 03 16:00:53 CEST 2003Send RRC DCCH RRCConnectionReleaseWed Sep 03 16:00:53 CEST 2003Receive RANAP Iu-ReleaseCommandWed Sep 03 16:00:55 CEST 2003Receive ALCAP REL - Release RequestWed Sep 03 16:00:55 CEST 2003Receive ALCAP REL - Release RequestWed Sep 03 16:00:55 CEST 2003Send ALCAP RLC - Release ConfirmWed Sep 03 16:00:55 CEST 2003Send ALCAP RLC - Release ConfirmWed Sep 03 16:00:59 CEST 2003Receive NBAP DedicatedMeasurementReportWed Sep 03 16:00:59 CEST 2003Receive NBAP DedicatedMeasurementReportWed Sep 03 16:00:59 CEST 2003Receive NBAP DedicatedMeasurementReportWed Sep 03 16:01:08 CEST 2003Receive RANAP Iu-ReleaseCommandWed Sep 03 16:01:08 CEST 2003Send RANAP ErrorIndication [message-not-compatible-with-receiver-state[99]]Wed Sep 03 16:01:09 CEST 2003Receive NBAP DedicatedMeasurementReportWed Sep 03 16:01:09 CEST 2003Receive NBAP DedicatedMeasurementReportWed Sep 03 16:01:09 CEST 2003Receive NBAP DedicatedMeasurementReportWed Sep 03 16:01:13 CEST 2003Receive NBAP RadioLinkFailureIndication [synchronisation-failure[10]]Wed Sep 03 16:01:19 CEST 2003Receive NBAP DedicatedMeasurementReportWed Sep 03 16:01:19 CEST 2003Receive NBAP DedicatedMeasurementReportWed Sep 03 16:01:19 CEST 2003Receive NBAP DedicatedMeasurementReportWed Sep 03 16:01:23 CEST 2003Receive RANAP Iu-ReleaseCommandWed Sep 03 16:01:23 CEST 2003Send RANAP ErrorIndication [message-not-compatible-with-receiver-state[99]]Wed Sep 03 16:01:29 CEST 2003Receive NBAP DedicatedMeasurementReportWed Sep 03 16:01:29 CEST 2003Receive NBAP DedicatedMeasurementReportWed Sep 03 16:01:29 CEST 2003Receive NBAP DedicatedMeasurementReportWed Sep 03 16:01:33 CEST 2003Receive NBAP RadioLinkFailureIndication [synchronisation-failure[10]]Wed Sep 03 16:01:38 CEST 2003Receive RANAP Iu-ReleaseCommandWed Sep 03 16:01:38 CEST 2003Send RANAP ErrorIndication [message-not-compatible-with-receiver-state[99]]Wed Sep 03 16:01:39 CEST 2003Send RRC DCCH SecurityModeCommand

Page 19

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5) IMSI Trace RANAP Protocol Error – continued

The NodeB/Cell detects an Radio Link problem with the Ue during Call Setup. The Ue was at

that time in Inter RNC softhandover. The first Radio Link Failure Indication was ignored by

the RNC as it came from the DRNC via RNSAP. Once the second cell, connected to the

SRNC, also reported an Radio Link Failure Indication, the RNC aborted the Radio Bearer

Setup and sent RAB Assignment Response „Radio Connection lost with Ue“ towards MSC.

In parallel the RNC sends RRC Connection Release to the Ue – The MSC answers with Iu-

Release Command message which seems to be wrong from the RNC protocol state as RNC

responses with Error Indication „message not comaptible with receiver state.

The biggest issue is that the RNC is not able to clear the RRC Resources, so the NodeB/Cell

continues to report Radio Link Failure Indication „synchronisation failure“. The MSC sends

in regular intervals Iu-Release Command and the RNC rejects always with Error Indication.

Note:Note: Protocol Error continues for about 1 minute, during that time possible Call Setups will

be rejected with „Requested Service Option not supported“

The Ue starts Call Setup and performs ActiveSet Update, however Measurement Control was

not received by the Ue anymore although IMSI-trace shows that RNC sent Measurement

Control towards NodeB. This indicates already downlink sychronisation problem. Then Ue

awaits Radio Bearer Setup from RNC.

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6) Interference / Pilot Pollution

TEMS log shows several strong server, but no dominant server situation.

Frequent link additions and deletions. See next page for typical screen shot.

Changes in RF situation required to establish dominant server. Change of downtilts. Increase tilts of far sites Change of azimuth.

Symptoms

Reason & Solution

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6) Interference / Pilot Pollution (TEMS)

Strong Signal shooting up from Donnersberger Brücke which is a far site!

Symptom

1 No dominant

server situation

causes frequent

Soft-HO

2 more than 3

Pilots are within

a 6dB RSCP-

window

3 Ec/Io is of

average quality

˜ -10dB

Page 22

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6) Interference / Pilot Pollution (Plot)

cell-id Scr_Code Hoehe_ Hoehe Azimuth Elek.DowntiltMXU7774C 130 525m 31.5m 310° 3°

Areas with more than 3 strong Pilots

occur quiteFrequently, because same Azimuths are

used inneighbor sites

cells having

the same

azimuth

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7) Call Rejection due to loss of RRC Release Complete message – Delayed Iu Release

After an RRC Connection Release (e.g. due to drop) it sometimes happens,

that the „RRC Connection Release Complete“ message is lost from the Ue.

In such cases the RNC is waiting a defined time period before it entirely

releases the resource on the Iu-interface.

This issue causes that the UMSC rejects a new call containing

CM_SERV_REQ with cause „Service Option not supportd“

Symptoms

Reason & Solution

It is not possible to establish two CS calls at the same time. Resources need

to be released before new connection can be established.

Decrease time the RNC waits until the resources are released.

Ue may perform Cell Update after drop according to 3GPP 25.331

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7) Call Rejection due to loss of RRC Release Complete message (TEMS)

The previous Call dropped due to bad coverage and Ue changes to Idle Mode

Symptoms

1 previous call

drops

abnormally

2 Ue changes to

Idle mode

3 New Call Setup

4 Good Ec/Io

5 Good RSCP

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7) Call Rejection due to loss of RRC Release Complete message (Iu-trace K1297)

Long Time From 2. MSG 3. MSG 4. MSG Procedure Code 5. MSG 6. MSG radioNetwork cause14:39:03,642,122 UMSC SD RL CC id-CommonID initiating..14:39:03,652,085 UMSC SD RL DT1 id-SecurityModeContr initiating..14:39:04,041,923 RNC SD RL DT1 id-SecurityModeContr successful..14:39:04,102,237 UMSC SD RL DT1 id-DirectTransfer initiating.. IDREQ14:39:04,401,936 RNC SD RL DT1 id-DirectTransfer initiating.. SETUP14:39:04,522,265 UMSC SD RL DT1 id-DirectTransfer initiating.. CPROC14:39:04,542,627 UMSC SD RL DT1 id-DirectTransfer initiating.. FACIL14:39:04,543,694 UMSC SD RL DT1 id-RAB-Assignment initiating..14:39:04,561,923 RNC SD RL DT1 id-DirectTransfer initiating.. IDRES14:39:06,791,932 RNC SD RL DT1 id-RAB-Assignment outcome14:39:07,527,879 UMSC SD RL DT1 id-DirectTransfer initiating.. PROGRES14:39:07,557,739 UMSC SD RL DT1 id-DirectTransfer initiating.. CONNECT14:39:07,921,920 RNC SD RL DT1 id-DirectTransfer initiating.. CONACK14:39:25,661,855 RNC SD RL DT1 id-Iu-ReleaseRequest initiating.. release-due-to-utran-generated-reason14:39:25,776,495 UMSC SD RL DT1 id-Iu-Release initiating.. release-due-to-utran-generated-reason14:39:32,826,903 RNC SD RL DT1 id-Iu-Release successful..14:39:32,872,642 UMSC SD RL RLSD14:39:32,886,910 RNC SD RL RLC

14:39:32,586,963 RNC SD RL CR id-InitialUE-Message initiating.. CMSREQ14:39:32,708,121 UMSC SD RL CREF id-DirectTransfer initiating.. CMSREJ Service Option not supported

The first call drops with „release due to utran generated reason, but the Iu-Release is

completed 7sec afterwards. In the meantime, the Ue tries to setup a new call which gets

rejected by MSC with cause „Service Option not supportd“ assumption: 2 outgoing

CS calls are not supported for one Ue at the same time.

Iu-trace extract – 1st call drops, 2nd call gets rejected right after CMSREQ

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7) Call Rejection due to loss of RRC Release Complete message (Iu + Iub trace K1297)

Long Time From 2. MSG 3. MSG 4. MSG Procedure Code 5. MSG radioNetwork14:39:25,661,855 RNC SD RL DT1 id-Iu-ReleaseRequest initiatingMess..release-due-to-utran-generated-reaso14:39:25,776,495 UMSC SD RL DT1 id-Iu-Release initiatingMess..release-due-to-utran-generated-reaso14:39:26,435,778 Node-B #3 (DCH #1 DL)FP DATA DCH14:39:26,435,778 Node-B #3 (DCH #1 DL)UM DATA DCHrrcConnectionRelease14:39:30,608,053 NBAP UL SD initiatingMessage id-commonMeasurement14:39:30,618,806 NBAP UL SD initiatingMessage id-commonMeasurement14:39:31,068,692 NBAP UL SD initiatingMessage id-radioLinkFailure synchronisation-failure14:39:32,826,903 RNC SD RL DT1 id-Iu-Release successfulOutc..14:39:32,872,642 UMSC SD RL RLSD14:39:32,886,910 RNC SD RL RLC

The Iu-resource gets released after about 7sec after the drop has been declared by RNC.

It seems that a Radio Link timer runs in NodeB to monitor the Ue‘s DCH. After the NodeB

(cell) has reported an Radio Link Failure towards RNC, the Iu resource is released (Iu-

Release successful Outcome).

Note: The Ue has notnot reported RRC Connection Complete

Iu Released

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8) Unclear Server Footprint

Often, but not always, together with pilot polution.

Tems log shows frequent active setupdates. Many 1a, 1b, 1c events

This causes signaling load in network.

Risk of link addition failure and drop is increased.

Mobile is always in SHO and ocupies more resources than necessary.

Symptoms

Reason & Solution

Establish clear best server.

Improve strong server and reduce not requested far server by changing

azimuth and downtilts.

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8) Unclear Server Footprint (TEMS)

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8) Unclear Server Footprint (Plot before)

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8) Unclear Server Footprint (plot improved)

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9) Data Upload Problem

Upload of large e-mails or ftp files is not possible. Download is not infected. Very unclear picture

Equipment settings Location

Possible Reasons Max. MTU for one equipment in the connection could be to

small or performs defragmentation. No all routers support 1500byte MTU.

With BlakHoleDetection the MTU is reduced to 536Byte. Upload is possible.

See special report.

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10) 3G to 2G HO - Ue lost after HCOM (K1297)

It can be seen that the HCOM is sent to the Ue, but after 15sec the UMSC sends a Iu-Release

because the InterRAT HO to GSM is not successful. If the InterRAT HO were successful a Iu-

Release with cause ‚successful Relocation‘ would be sent by UMSC. We know from the Ue

that the call dropped in our trace. It is also obvious that the RNC waits more than 15sec and

does not realize any problem during the handover. Here it is vital to check what is the setting

for the timer „T_RELOC_COMPLETE“ in RNC - if exist - as no handover failure with e.g.

„contact with Ue lost“ is reported by RNC.

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10) 3G to 2G HO - Ue lost after HCOM

1. What is the timer setting in RNC for InterRAT HO to guard the handover – in GSM it

would be BSSMAP T8. In UMTS there must be a so called T_RELOC_COMPLETE timer

to initiate a Iu-ReleaseRequest with cause e.g. „contact with Ue lost“

2. Possible protocol error. The RNC does not react upon the Release Command from

UMSC by releasing the resources. On the contrary the UMSC repeats after 15sec the Iu-

Release again.

3. The Node finally detects a Radio Link Failure cause „synchronisation failure“, but with

about 30sec after the Handover Command sent on RLC/MAC. Here it is important to get

the timer settings checked as we experience a big inbalance in detecting a drop

between Ue and UTRAN, means the Ue goes back to Idle mode much quicker than the

UTRAN detects it. This issue is also part of ticket: VTT00020680A

Open Question about 3G to 2G HO:

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10) 3G to 2G HO – Relocation Timer overview

In UMR2.0, the value of below mentioned timers cannot be changedThis is possible only from UMR3.0 onwards. Please find in brackets the adjustable ranges.

1. T-Relocation Preparation = 60s* (1-180)2. T-Relocation Overall = 60s* (1-1803. T-Relocation Cancel = 10s* (1- 60)

T-Relocation PREPARATION: on Iu between UL-DT1(Relocation Request) andDL-DT1(Relocation Command).

T-Relocation OVERALL: on Iu between DL-DT1(RelocationCommand=>RRC-HO-from-Utran-command) and DL Iu-Relase command

T-Relocation CANCEL: after RRC-HO-from-Utran-command failure, andbetween Iu-UL(Relocation Cancel) and DL-DT1(RelocationAcknowledge.

* UMR 2.7/2.5

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10) 3G to 2G HO – Relocation Flows [Normal]

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10) 3G to 2G HO – Relocation Flows [Error case]

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11) DL Radio Resources not available

Symptoms

Reason & Solution

Good RF condition – EcNo and RSCP are good

RRC Connection Release with cause “normal Event”

In case of call-setup no Radio Bearer Setup message is seen

RRC Connection Reject with cause “unspecified” is seen

Problem may occur in high load situation e.g. when a PO call was running

Problem may appear and disappear suddenly

Problem with Allocating the Spreading Factor in NodeB

NodeB Reset fixes the problem temporarily

New software in NodeB is a permanent solution

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11) DL Radio Resources not available (K12 Iu trace)

After RAB-Assignment, Iu-ALCAP tries to establish the terrestrial connection between

MSC and RNC for the User Plane.

RNC responds with RAB-Assignment „failure in the radio interface procedure because of

NBAP Failure „dl-radio-resources-not-available“. The reason for this behavior is because

the synchronised Radio Link Reconfiguration had an unsuccessful outcome.

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11) DL Radio Res. not available (K12 trace Iu+Iub)

unsuccessful outcome for synchronised Radio Link Reconfiguration Preparation

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11) DL Radio Resources not available (K1297 trace)

The RRC Connection Release has as a cause „normal Event“ so a problem in UTRAN is not

visible for the Drive-test personnel when looking at TEMS

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11) DL Radio Resources not available (K1297 trace)

It can be seen that the failure „dl-resources not available“ can also be the reason for

seeing RRC Connection Reject with cause „unspecified“

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12) Faulty RACH prevents Call Setup but SHO OK

Symptoms

Reason & Solution


Ue (TEMS) shows sending of RRC Connection Request on RACH TrCH up to

the max. number or retransmissions

Not any response from UTRAN – e.g. RRC Connection Setup is missing

K1297 shows RACH decoding error or CRC checksum error

SHOs into the affected cell and out of that cell work fine

Not available yet – however the indications point to problem on CCCH

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12) Faulty RACH prevents Call Setup but SHO OK –K1297 trace

Long Time From 2. MSG 3. MSG Procedure Code received total wide

band powertransmitted

carrier power16:53:26,974,189 NBAP UL SD initiatingMessage id-commonMeasurement 70 16:53:26,981,439 NBAP UL SD initiatingMessage id-commonMeasurement 1816:53:27,810,070 NBAP UL SD initiatingMessage id-commonMeasurement 70 16:53:27,820,814 NBAP UL SD initiatingMessage id-commonMeasurement 1816:53:29,404,938 NBAP UL SD initiatingMessage id-commonMeasurement 70 16:53:29,415,688 NBAP UL SD initiatingMessage id-commonMeasurement 1816:53:34,787,349 C2 RACH UL FP DATA .. 16:53:36,973,115 NBAP UL SD initiatingMessage id-commonMeasurement 70 16:53:36,983,998 NBAP UL SD initiatingMessage id-commonMeasurement 1816:53:37,812,246 NBAP UL SD initiatingMessage id-commonMeasurement 70 16:53:37,819,627 NBAP UL SD initiatingMessage id-commonMeasurement 1816:53:37,883,994 C2 RACH UL FP DATA .. 16:53:39,404,112 NBAP UL SD initiatingMessage id-commonMeasurement 70 16:53:39,414,616 NBAP UL SD initiatingMessage id-commonMeasurement 1816:53:40,977,379 C2 RACH UL FP DATA .. 16:53:46,972,043 NBAP UL SD initiatingMessage id-commonMeasurement 70 16:53:46,982,680 NBAP UL SD initiatingMessage id-commonMeasurement 1816:53:47,811,556 NBAP UL SD initiatingMessage id-commonMeasurement 70 16:53:47,822,054 NBAP UL SD initiatingMessage id-commonMeasurement 1816:53:49,406,412 NBAP UL SD initiatingMessage id-commonMeasurement 70

The „C2“ indicates the 3rd sector (C0 = 1st sector and C1=2nd sector)

After the RACH has been relayed to the RNC there is no response from the RNC. Reason

for that are decoding errors or wrong CRC-checksum inside the RACH.

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12) Iub shows RACH decoding errors or CRC checksum error – K1297 trace

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12 Iub shows RACH decoding errors or CRC checksum error – K1297 trace

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12) Iub Correct decoding RACH – Example trace

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12) Drive-test log - RRC Connection Request w/o response from UTRAN

Symptoms

1 Good Ec/No

2 Good RSCP

3 Ue sends max.

number of RRC

Connection

Requests without

any Ack or Nack

from UTRAN

4 Ue back in Idle

Mode

5 SHO into

„faulty“ are ok

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12) Drive-test log – SHO into faulty cell(s) are OK

The TEMS log

shows that

SHO into and

out of the

faulty cell are

fine – no

problem visible

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12) Summary

The faulty cell(s) behave normal – Pilot Channel can be decoded and soft-handover in and out of

the faulty cell(s) are possible.

Call-Setups in those faulty cells are prevented by decoding or CRC checksum error on the

RACH-transport channel. As the K1297 trace monitors the Iub-interface, it cannot be determined

if the error was introduced on the Air-interface or inside the NodeB.

From the drive-test it looks similar like a sleeping cell, however soft-handover are working which

prove that the RF-path and channels are okay. The cell is active on Uu but even after several

RACH‘s still no response from UTRAN.

This error points to some hardware problem on the CCCH, as DCH channels work fine.

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13) No Call Setup possible but SHO OK

Symptoms


Ue (TEMS) does not send any RRC Connection Request on RACH-TrCH

Not any response from UTRAN – e.g. RRC Connection Setup is missing

SHOs into the affected cell and out of that cell work fine

RNC database shows that neither Cell Barred nor Operator Barring is used,

but SYSINFO Type 3 indicates Operator Barring (TEMS)

Reason & Solution

Cell Barred for Access Flag is set

Cell Barred for Operator Use is set

Perform an Audit on that NodeB to align RNC and NodeB database

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13) No Call Setup possible – SysInfo 3 Operator Barring

System Info Type 3

Symptoms

1 Good Ec/No

2 Good RSCP

3 No RRC

Connection

Request from

Ue

Cellname/SC and UARFCN are ok

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13) System Info Type 3 – No Barring

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14) Ue bug – too high RTWP

Symptoms


Faulty Ue drops suddenly during or after Call-Setup for no obvious reason

Other Ue(s) in parallel also drop for no obvious reason

TEMS RRC Connection Release cause ‘unspecified’

K1297 CommonMeasurement indicates very high RTWP (values >150 15dB)

Trace on Iub with K1297 and test all Ue’s for unusual high RTWP

Throw away Ue’s causing high RTWP

Issue seen so far on Siemens/Motorola Ue (U10 or U830)

Reason & Solution

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Long Time 3. MSG 4. MSG Procedure Code 6. MSG received-total-wide-band-power radioNetwork releaseCause13:32:03,300,666 initiatingMessage id-commonMeasurement 13:32:11,963,035 initiatingMessage id-commonMeasurement 70 13:32:11,974,026 initiatingMessage id-commonMeasurement 13:32:12,859,539 initiatingMessage id-commonMeasurement 70 13:32:12,870,040 initiatingMessage id-commonMeasurement 13:32:13,292,675 initiatingMessage id-commonMeasurement 70 13:32:13,300,059 initiatingMessage id-commonMeasurement 13:32:22,862,047 initiatingMessage id-commonMeasurement 70 13:32:22,869,181 initiatingMessage id-commonMeasurement 13:32:23,291,660 initiatingMessage id-commonMeasurement 70 13:32:31,964,773 initiatingMessage id-commonMeasurement 149 13:32:31,972,148 initiatingMessage id-commonMeasurement 13:32:32,684,387 RL DT1 id-DirectTransfer SETUP 13:32:32,764,374 RL DT1 id-DirectTransfer IDRES 13:32:32,860,915 initiatingMessage id-commonMeasurement 224 13:32:32,871,659 initiatingMessage id-commonMeasurement

13:32:32,959,332 RL

DT1 id-RAB-Assignment failure-in-the-radio-interface-procedure

13:32:33,036,095 RL

DT1 id-Iu-Release

release-due-to-Utran generated reason

13:32:33,647,726 RRC Connection Release unspecified

13:32:33,863,641 RRC Connection Release Complete

13:32:33,290,510 initiatingMessage id-commonMeasurement 124 13:32:41,963,621 initiatingMessage id-commonMeasurement 70 13:32:41,970,863 initiatingMessage id-commonMeasurement 13:32:42,859,875 initiatingMessage id-commonMeasurement 70 13:32:42,870,625 initiatingMessage id-commonMeasurement 13:32:43,289,475 initiatingMessage id-commonMeasurement 70 13:32:43,300,474 initiatingMessage id-commonMeasurement 13:32:51,962,346 initiatingMessage id-commonMeasurement 70

14) Faulty Ue causes high RTWP with drop of Ue‘s

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14) Faulty Ue causes high RTWP with drop of Ue‘s

Long Time 3. MSG 4. MSG Procedure Code 6. MSG received-total-wide-band-power radioNetwork releaseCause13:32:43,300,474 initiatingMessage id-commonMeasurement 13:32:51,962,346 initiatingMessage id-commonMeasurement 70 13:32:51,973,337 initiatingMessage id-commonMeasurement 13:32:52,862,349 initiatingMessage id-commonMeasurement 70 13:32:58,303,387 initialDirectTransfer CMSREQ 13:32:59,383,284 uplinkDirectTransfer SETUP 13:33:01,961,562 initiatingMessage id-commonMeasurement 314

13:32:02,099,883 RL DT1 id-Iu-Release

release-due-to-Utran generated reason

13:33:02,767,047 RRC Connection Release unspecified

13:33:02,861,322 initiatingMessage id-commonMeasurement 249

13:33:02,983,573 RRC Connection Release Complete

13:33:03,290,895 initiatingMessage id-commonMeasurement 124

It can be seen that as soon as the faulty Ue makes a phone call (SETUP message), the RTWP

rises by more than 20dB. This leads to a drop and also other mobiles will drop in that Cell as

well.

The RRC release cause is „unspecified“

Reason for high RTWP is the high output power of the Ue. Such an Ue will not power down as

ordered by NodeB, therefore the high RTWP.

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15) TEMS bug – no Measurement Reporting

Symptoms

Initial Measurement Control is sent ( for MOC: right after CM SERV REQ)

Measurement Control contains Neighbor cells SC as specified in the Neighbor list

After Connect Ack the Ue stops sending any measurement report towards RNC

In most of the cases call drops if not aborted or Disconnected earlier

Reason & Solution

TEMS bug – not yet confirmed by TEMS Support

After Disconnect and new call Setup problem disappears

Issue seen so far on Qualcom Ue in conjunction with TEMS only

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15) TEMS bug – no Measurement Reporting

Symptoms

1 After ‚Connect Ack‘

no more messages

from Ue are sent to

RNC

2 Ue measures

neighbors but no

measurement reports

are sent to RNC

3 Ec/Io of Serving Cell

drops, Neighbor Ec/Io

are very good

4 Once a new call is

set up, problem

disappears

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16) No camping on cell – but SHO into that cell is ok

Symptoms

Problem seems only to affect the Siemens / Motorola Ue U10 / A830 model

If the Measurement Control message contains one or more repeated Scrambling

Code(s) (neighbor list in RNC-DB contains 2 times the same Scrambling Code) the Ue

sends Measurement Control Failure Message with cause ‘invalid configuration’

The Ue cannot camp on such cell(s) - only via SHO a call can be made on that cell(s)

The SysInfo Type 11 obtained in Idle Mode contains one or more repeated SC’s

Reason & Solution

Delete double neighbor entries in RNC-DB

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16) 1 No camping on cell – but SHO into that cell is ok

During a call,

the Ue can

perform SHO

with cell(s)

having an

erronomeous

Neighbor list

same SC is

defined twice

as neighbor.

The Meas

Control Failure

is ignored by

RNC.

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Textdokument

On the left there is an extract of a faulty neighbor-list.

Two neighbors are defined twice with the same Scrambling

Code.

The complete Measurement Control Message can be found in

the attached ‚Textdokument‘.

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SysInfo 11

The SysInfo 11

contains double

SC‘s which

cause the Ue to

change PLMN

After having read

SysInfo 11 the Ue

changes the

UARFCN ( try to

find another

PLMN). This is

shown on the next

slide.

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After the Ue

has received

the SysInfo

Type 11 with

the doubling

of Scrambling

Codes, the Ue

leaves the

HPLMN

Frequency and

searches for

different

network(s). It

goes into

‚limited

service state‘

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17) Blocked Call – CM Service Reject with cause ‘Network Failure’

Symptoms

Softhandover into the affected cell and out of the cell are ok

Ec/Io and RSCP are good

TEMS indicates ‘Blocked Call’

Layer 3 messages shows ‘ CM Service Reject with cause “Network Failure” ’

All Ues are affected

Reason & Solution

Cell(s) are not entered in (U)MSC database

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17) Blocked Call – CM Service Reject (TEMS)

Symptoms

1 Good RF situation

2 all CM Serice

Requests are

rejected with cause

‚Network failure‘

3 Soft-HO in and out

of affected cell(s)

is/are OK

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17) Blocked Call – RRC Connection Release ‘unspecified’

Symptoms

1 RNC aborts

the

connection

with RRC

Connection

Release

‚unspecified‘

Documents

UMTS Troubleshooting 18-10-03