Download - RrcReEstablishment UA6 KTS DR5
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Patrice Doulin TIS-ONE (Network Performance)
The 06th of July, 2009
UA6 RRC Re-Establishment CS and PS
Feature Assessment
UA6 KTS for DR5
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2 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
Agenda of UA6 CS and PS RRC Re-Establishment assessment
1. Feature overview
2. Activation strategy
3. Synchronisation loss detection
4. Performance Monitoring (FOA1, FOA2)
5. Optimization proposal (T313/ N313)
6. Conclusion
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3 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
1CS and PS RRC Re-Establishment
Feature overview
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4 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
UA6.0 CS and PS RRC Connection Re-establishment
Feature Overview
Objective: The feature RRC Re-establishment CS and PS (33821 and 34290) will reduce the PS
and CS call drop rates when the UE will temporarily loose his coverage.
End-user benefits:
When a user temporarily moves into an area of poor coverage, and moves back into
good coverage, the call will not be dropped. This is especially beneficial to users
on calls whilst traveling through tunnels etc, the call will not drop.
Activation flags:
The feature will be controlled through these three OAM parameters. 33821 & 34290: isPsRrcReestablishAllowed controls the PS support for RRC Re-
establishment
34290: isCsRrcReestablishAllowed controls the CS support for RRC Re-establishment .
34290: isPSRrcReestablishforICFailureAllowed controls the PS RRC Re-establishment when an invalid configuration response is received for a HSDPA call performing a UL rate
change procedure (Qualcomm bug).
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5 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
UA6.0 CS and PS RRC Connection Re-establishment
Feature Overview Principle
Note, there are some scenarios that RRC Connection re-establishment does not
support: Situations where cell reselection occurs to a cell that is not a neighbour of the cell where
the call started
Situations where CEM card pulls or TMU resets occur - i.e. hardware failures on the RNC or
BTS
Principles:
When a UE detects a Radio Link Failure (e.g. UE temporarily loosing radio coverage
when going into a tunnel) or an AM RLC unrecoverable error and timers T314 &
T315 are different from zero, the UE goes to CELL_FACH state, performs a cell
reselection and starts a CELL UPDATE procedure.
Either the RNC is informed of the failure and of the UE state change when it receives the
CELL UPDATE message with cause "Radio Link Failure" or "RLC unrecoverable error",
Or the RNC detects RLC unrecoverable error before a CELL UPDATE message is received, or
the Node B indicates a Radio Link Failure to the RNC before a CELL UPDATE message is
received.
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6 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
UA6.0 CS and PS RRC Connection Re-establishment
Principle
If the Cpich Ec/No is above the minimum threshold, as defined in the data parameter rrcReestablishCSThreshold or/and rrcReestablishPSThreshold. If the CpichEc/No is below the threshold, the call will be dropped, by sending an IuReleaseRequest to the Core Network with the cause value Radio Connection with UE Lost.
Two new parameters rrcReestPSMaxAllowedTimer and rrcReestCSMaxAllowedTimertimer is introduced in order to tells the RNC how long to wait for cell update from the UE to start doing re-establishment for the calls.
Multi-service caseIn the multi-service case, then the re-establishment will only proceed if the
Cpich_Ec/No is above the lower of the PS and CS threshold parameters: rrcReestablishCSThreshold for CS domain rrcReestablishPSThreshold for PS domain
The RNC Re-establishment timer applied is the shortest interval of rrcReestPSMaxAllowedTimer and rrcReestCSMaxAllowedTimer.
High Recommendation: If only PS RRC Re-establishment is activated and isCSReestablishmentAllowed =
false, it is needed to set timers T314 and rrcReestCSMaxAllowedTimer to a non-zero value.
If either of these timers is set to 0, when the CS re-establishment global flag is set to false - PS re-establishment will not work.
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7 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
UA6.0 CS and PS RRC Connection Re-establishment
Triggers conditions
Trigger condition for RLC Unrecoverable error
Trigger condition for Radio Link Failure
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8 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
2CS and PS RRC Re-Establishment
Activation strategy
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9 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
Activation Strategy
Strategy for CS and PS RRC Re-establishment activated
isCsRrcReestablishAllowed = True
isPsRrcReestablishAllowed = True
isPSRrcReestablishforICFailureAllowed = True
If QCT chipsets are present on the network, this flag need to be set to True.
rrcReestCSMaxAllowedTimer = t314_12S
rrcReestPSMaxAllowedTimer = t315_180S
rrcReestablishCSThreshold = -12.0 dB ( inferior to cpichEcNoThresholdUsedFreq2D
for CSspeech)
rrcReestablishPSThreshold = -12.0 dB ( inferior to cpichEcNoThresholdUsedFreq2D
for PS)
T314 = t314_8S
T315 = t315_180S
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10 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
3CS and PS RRC Re-Establishment
Synchronisation loss detection
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11 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
UA6.0 CS and PS RRC Connection Re-establishment
Drops due to bad radio conditions
A drop due to bad radio conditions is detected:
At Radio Link layer, after 2.5 seconds of UL or DL Radio Link
synchronization loss
At RLC layer, by a loss of RLC acknowledgements leading to a RLC
unrecoverable error (SRB RLC error is detected in 4,8 seconds)
DL Radio LinkSynchronization
DL Radio LinkSynchronization
UL RLC error detection
UL Radio LinkSynchronization
RNC
DL RLC error detection
UL Radio LinkSynchronization
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12 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
UA6.0 CS and PS RRC Connection Re-establishment
Radio drop at RLC layer
RLC Acknowledged Mode provides
Acknowledgement of RLC-PDU transmitted. A sequence number is present in
the RLC header, for incremental numbering of RLC PDUs
Error correction through retransmission mechanism. If no answer to polling
after pollingTimer, PDU is retransmitted up to maxDat times before the SDU is
discarded with a PDU reset. PDU reset can be retransmitted
maxNbrOfResetRetrans times (1 means no retransmission).
For SRB3.4, pollingTimer = 120 ms, maxDat = 40, maxNbrOfRetrans = 1 (FOA2
values)
RNC
UE
RLC (L2)PDU PDU PDU
If no answer after pollingTimer, PDU is resent
Up to maxDatretransmissions before RLC buffer
is discarded.
Call will drop after 4,8 seconds if no ACK is received.
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13 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
UA6.0 CS and PS RRC Connection Re-establishment
Radio drop at Radio Link layer
For the dedicated channels, synchronization primitives are used to indicate the
synchronization status of radio links, both in uplink and downlink.
Uplink Radio Link Synchronization is based on:
Synchronization check of all radio frames in Layer 1 of the NodeB, for all radio link
sets
In-sync / Out-of-sync status management
DPCCH quality estimation using the SIR measured every time slot and averaged over a
window of 10ms, and the BLER of the received frames
Detection of DL radio link failures is performed by the UE, using the following
algorithm:
In cell DCH state, after receiving N313 consecutive "out of sync" indications from layer
1 for the established DPCCH, the UE start timer T313 :
upon receiving N315 successive "in sync" indications from layer 1, the UE stops and
resets timer T313.
If T313 expires, radio Link Failure condition is fulfilled. UE sends a Cell Update
message with cause Radio Link failure
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14 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
RRE Call flow : UL Radio Link Failure detection case
UE NodeB RNC CN
NBAP Radio Link Failure Indication
RLC Unrecoverable Error or Radio Link Failure detected by RNC
Radio Link Deletion Request
Radio Link Deletion Response
Alcap Release
rrcReestPSMaxAllowedTime
r and rrcReestCSMaxAllowedTime
r timer started
waiting for Cell Update from UE
RRC Cell Update (Cause RL Failure or RLC)
Stop timer
The Ec/No threshold in the RRC Cell Update message should be checked
to ensure it is higher than the configured parameter
rrcReestablishCsThreshold/ rrcReestablishPsThreshold
Radio Link Setup Request
Radio Link Setup Response
Alcap & FP Synch
RRC Cell Update Confirm
Radio Bearer ReconfComplete
Loss of Uplink Synchro detection
UE Measurements
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15 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
RRE Call flow : DL Radio Link Failure detection case
UE NodeB RNC CN
UE Measurements
Radio Link Deletion Request
Radio Link Deletion Response
Alcap Release
RRC Cell Update (Cause RL Failure or RLC)
T314/T315 expired IE is set to FALSE in the message
The Ec/No threshold in the RRC Cell Update message should be checked
to ensure it is higher than the configured parameter
rrcReestablishCsThreshold/ rrcReestablishPsThreshold
Radio Link Setup Request
Radio Link Setup Response
Alcap & FP Synch
RRC Cell Update Confirm
Radio Bearer ReconfComplete
Loss of Downlink Synchro detectionStop
rrcReestPSMaxAllowedTimer and
rrcReestCSMaxAllowedTimer timer if running
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16 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
4UA6 RRC Re-Establishment Monitoring
Performance Monitoring (FOA1, FOA2)
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17 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
RRE_CS_Call_drop_overview_R - RNC : LYONTRIO2 (LYONTRIO2) - 06/01/2009 to 06/30/2009 (Working Zone: TRIO2 - Medium)
0
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E
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0.18%
0.28%
0.38%
0.48%
0.58%
0.68%
0.78%
0.88%
0.98%
%
IuAbnormalReleaseRequest_IU008_R_CsVoice(UIU008_R_CsVoice)CallDropRate_IU007_R_CsVoice(UIU007_R_CsVoice)
C S _ c a ll_ d ro p _ o v e rv ie w - 0 4 /2 2 /2 0 0 9 0 1 : 0 0 T o 0 5 /0 3 /2 0 0 9 0 9 :4 5 - V E R N C 0 2
0
5 00
1 0 00
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2 0 00
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3 5 00
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%
IuA b no rm a lR e le a s e R e q ue s t_ IU 0 0 8 _ C _ C s V o ice (U IU 0 0 8 _ C _ C sV o ic e )C a llD ro p R a te _ IU 0 0 6 _ C _ C s V o ic e (U IU 0 0 6 _ C _ C s V o ice )
CS Performance Monitoring - CS Call drop
The CS Call drop
rate has been
improved of 20%
on the FOA2
network after the
activation of RRC
Re-establishment
feature.
RRE activation on 22/04 at 23h09
RRE activation
FOA1
FOA2
Before RRE ActivationFrom 01/06 to 17/06
After RRE activationFrom 19/06 to 30/06
CallDropRate_IU007_R_CsVoice(UIU007_
R_CsVoice)(%) 0.57% 0.48%
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18 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
C S _ d r o p _ c a u s e s - 0 4 /0 1 /2 0 0 9 T o 0 5 /0 3 /2 0 0 9 - V E R N C 0 2
0
5 0 0 0
1 0 0 0 0
1 5 0 0 0
2 0 0 0 0
2 5 0 0 0
3 0 0 0 0
3 5 0 0 0
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V S _ Iu Re le a s e Re q C s _ A b n o r ma lCo n d itio n Time r Re lo c Ex p ir y ( U5 7 6 _ 5 ) V S _ Iu Re le a s e Re q C s _ Co n n e c tio n W ith N o d e B L o s t( U5 7 6 _ 1 0 )V S _ Iu Re le a s e Re q C s _ DlRL CErr S R B ( U5 7 6 _ 7 ) V S _ Iu Re le a s e Re q C s _ Fa ilu r e In T h e Ra d io In te r f a c e Pr o c e d u r e ( U5 7 6 _ 1 3 )V S _ Iu Re le a s e Re q C s _ No R e ma in in g RA B ( U5 7 6 _ 1 2 ) V S _ Iu Re le a s e Re q C s _ No R e s o u r c e A v a ila b le ( U5 7 6 _ 1 4 )V S _ Iu Re le a s e Re q C s _ O a mIn te r v e n tio n ( U5 7 6 _ 0 ) V S _ Iu Re le a s e Re q C s _ O th e r Ca u s e ( U5 7 6 _ 6 )V S _ Iu Re le a s e Re q C s _ Ra d io Co n n e c t io n W ith U e L o s t( U5 7 6 _ 4 ) V S _ Iu Re le a s e Re q C s _ Re le a s e D u e To U tr a n G e n e r a te d Re a s o n ( U5 7 6 _ 1 1 )V S _ Iu Re le a s e Re q C s _ Re p e a te d In te g r ity Ch e c kFa ilu r e ( U5 7 6 _ 2 ) V S _ Iu Re le a s e Re q C s _ T3 6 0 Ex p ir y ( U5 7 6 _ 9 )V S _ Iu Re le a s e Re q C s _ Ue G e n e r a te d S ig n a llin g Co n n e c tio n Re le a s e (U 5 7 6 _ 3 ) V S _ Iu Re le a s e Re q C s _ UlRL CErr S R B ( U5 7 6 _ 8 )V S _ Iu Re le a s e Re q C s _ Un s p e c if ie d Fa ilu r e ( U5 7 6 _ 1 )
CS Performance Monitoring - IU CS Release Causes
RRE activation on 22/04 at 23h09
Increase of Iu CS release Req pattern
error : UL_RLC_Err_SRB
FOA1
Following the introduction of the
feature a new scenario directly
linked to the feature will lead to
pegging the counters
IuRelReq.UlRlcErr.SRB
This scenario corresponds
basically to the case where the
cellUpdateConfirm to re-establish
the call is not correctly received
by the mobile.
This increase is not really a
drawback of the RRE feature as
this behaviour where expected
(due to the implementation) and
the global retainability KPI has
been improved.
Iu Release Req CS
02000400060008000
100001200014000160001800020000
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VS_IuReleaseReqCs_AbnormalConditionTimerRelocExpiry(U576_5) (Event) VS_IuReleaseReqCs_ConnectionWithNodeBLost(U576_10) (Event)VS_IuReleaseReqCs_DlRLCErrSRB(U576_7) (Event) VS_IuReleaseReqCs_FailureInTheRadioInterfaceProcedure(U576_13) (Event)VS_IuReleaseReqCs_NoRemainingRAB(U576_12) (Event) VS_IuReleaseReqCs_NoResourceAvailable(U576_14) (Event)VS_IuReleaseReqCs_OamIntervention(U576_0) (Event) VS_IuReleaseReqCs_OtherCause(U576_6) (Event)VS_IuReleaseReqCs_RadioConnectionWithUeLost(U576_4) (Event) VS_IuReleaseReqCs_ReleaseDueToUtranGeneratedReason(U576_11) (Event)VS_IuReleaseReqCs_RepeatedIntegrityCheckFailure(U576_2) (Event) VS_IuReleaseReqCs_T360Expiry(U576_9) (Event)VS_IuReleaseReqCs_UeGeneratedSignallingConnectionRelease(U576_3) (Event) VS_IuReleaseReqCs_UlRLCErrSRB(U576_8) (Event)VS_IuReleaseReqCs_UnspecifiedFailure(U576_1) (Event)
FOA2
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19 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
PS_call_drop_overview _cell - 04/01/2009 To 05/03/2009 - VERNC02
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.0%
2.0%
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10.0%
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18.0%
%
IuA bnormalReleaseReques t_IU008_C_HSUPA (UIU008_C_HSUPA ) IuA bnormalReleaseReques t_IU008_C_HSDPA (UIU008_C_HSDPA )IuA bnormalReleaseReques t_IU008_C_ULpsR99(UIU008_C_ULpsR99) CallDropRate_IU006_C_Ps(UIU006_C_Ps)HSDPA CallDropIndicator_HSDPA 032_CR(UHSDPA 032_CR)
PS Performance Monitoring
PS Call drop
A good improvement is
observed on the PS Call
drop rate , - 50% of
decrease for FOA2
customer
RRE activation on 22/04 at 23h09
Average before RRE Activation (From 01/04/09
to 22/04/09)
Average after RRE activation (From
23/03/09 to 03/05/09)CallDropRate_IU006_C_Ps(UIU006_C_Ps)(%) 11.23% 9.04%
FOA1
RRE_PS_Call_drop_overview_R - RNC: LYONTRIO2 ( LYONTRIO2 ) - 06/01/2009 To 06/30/2009 (Working Zone: TRIO2 - Medium)
.%
1.%
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IuAbnormalReleaseRequest_IU008_R_Ps(UIU008_R_Ps)(Event)CallDropRate_IU007_R_Ps(UIU007_R_Ps)(%)
RRE activation
B efo re R R E A c tivatio nF rom 0 1 /0 6 to 1 7 /0 6
A fter R R E a c tiva tio nF rom 1 9 /06 to 30 /0 6
C allD ro p R a te_ IU0 0 7 _R _ P s(U IU 0
0 7 _R _P s)(% )5 .3 7% 2.7 4 %
FOA2
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20 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
P S _ d r o p _ c a u s e s - 0 4 /0 1 /2 0 0 9 T o 0 5 /0 3 /2 0 0 9 - V E R N C 0 2
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5 0 0 0 0
1 0 0 0 0 0
1 5 0 0 0 0
2 0 0 0 0 0
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3 0 0 0 0 0
3 5 0 0 0 0
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t
V S _ Iu R e le a s e R e q P s _ A b n o rm a lC o n d it io n T im e rR e lo c E x p iry (U 5 9 9 _ 7 ) V S _ Iu R e le a s e R e q P s _ C e l lR e s e lF a il (U 5 9 9 _ 1 9 )V S _ Iu R e le a s e R e q P s _ C o n n e c t io n W it h N o d e B L o s t (U 5 9 9 _ 1 3 ) V S _ Iu R e le a s e R e q P s _ D lR L C E rrS R B (U 5 9 9 _ 8 )V S _ Iu R e le a s e R e q P s _ D lR L C E rrTR B (U 5 9 9 _ 1 0 ) V S _ Iu R e le a s e R e q P s _ F a ilu re In Th e R a d io In t e rfa c e P ro c e d u re (U 5 9 9 _ 1 6 )V S _ Iu R e le a s e R e q P s _ Iu U s e rP la n e F a ilu re (U 5 9 9 _ 1 ) V S _ Iu R e le a s e R e q P s _ N o R e m a in in g R A B (U 5 9 9 _ 1 5 )V S _ Iu R e le a s e R e q P s _ N o R e s o u rc e A va ila b le (U 5 9 9 _ 1 7 ) V S _ Iu R e le a s e R e q P s _ O a m In t e rve n t io n (U 5 9 9 _ 2 )V S _ Iu R e le a s e R e q P s _ O t h e rC a u s e (U 5 7 7 _ 8 ) V S _ Iu R e le a s e R e q P s _ P h y C h n R e e s t a b F a i l(U 5 9 9 _ 2 1 )V S _ Iu R e le a s e R e q P s _ R a d io C n x U e L o s t (U 5 9 9 _ 6 ) V S _ Iu R e le a s e R e q P s _ R e le a s e D u e To U t ra n G e n e ra t e d R e a s o n (U 5 9 9 _ 1 4 )V S _ Iu R e le a s e R e q P s _ R e p e a t e d In t e g rit y C h e c k F a ilu re (U 5 9 9 _ 4 ) V S _ Iu R e le a s e R e q P s _ T3 0 5 E x p iry (U 5 9 9 _ 1 8 )V S _ Iu R e le a s e R e q P s _ T3 6 0 E x p iry (U 5 9 9 _ 1 2 ) V S _ Iu R e le a s e R e q P s _ U e G e n e ra t e d S ig n a l lin g C o n n e c t io n R e le a s e (U 5 9 9 _ 5 )V S _ Iu R e le a s e R e q P s _ U lR L C E rrS R B (U 5 9 9 _ 9 ) V S _ Iu R e le a s e R e q P s _ U lR L C E rrTR B (U 5 9 9 _ 1 1 )V S _ Iu R e le a s e R e q P s _ U n s p e c i fie d F a i lu re (U 5 9 9 _ 3 ) V S _ Iu R e le a s e R e q P s _ U s e rIn a c t ivit y (U 5 9 9 _ 0 )V S _ Iu R e le a s e R e q P s _ U t ra n P a g e F a il (U 5 9 9 _ 2 0 )
PS Performance Monitoring
IU PS Release Causes
Signficant decrease of the
following IU Release Req PS
cause : DL_RLC_Err_SRB and
DL_RLC_Err_TRB after the
RRE feature activation
we can assume the RRE
feature save most of these
failures.
RRE activation on 22/04 at 23h09
The amount of IU Release
Request for the PS Rab
remains stable.
Significant decreased of the DL RLC Error on SRB
RRE_PS_drop_causes_CR - RNC: LYONTRIO2 ( LYONTRIO2 ) - 06/01/2009 To 06/30/2009 (Working Zone: TRIO2 - Medium)
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
06/01
/2009
06/02
/2009
06/03
/2009
06/04
/2009
06/05
/2009
06/06
/2009
06/07
/2009
06/08
/2009
06/09
/2009
06/10
/2009
06/11
/2009
06/12
/2009
06/13
/2009
06/14
/2009
06/15
/2009
06/16
/2009
06/17
/2009
06/18
/2009
06/19
/2009
06/20
/2009
06/21
/2009
06/22
/2009
06/23
/2009
06/24
/2009
06/25
/2009
06/26
/2009
06/27
/2009
06/28
/2009
06/29
/2009
06/30
/2009
E
v
e
n
t
VS_IuReleaseReqPs_AbnormalConditionTimerRelocExpiry(U599_7)(Event) VS_IuReleaseReqPs_CellReselFail(U599_19)(Event)VS_IuReleaseReqPs_ConnectionWithNodeBLost(U599_13)(Event) VS_IuReleaseReqPs_DlRLCErrSRB(U599_8)(Event)VS_IuReleaseReqPs_DlRLCErrTRB(U599_10)(Event) VS_IuReleaseReqPs_FailureInTheRadioInterfaceProcedure(U599_16)(Event)VS_IuReleaseReqPs_IuUserPlaneFailure(U599_1)(Event) VS_IuReleaseReqPs_NoRemainingRAB(U599_15)(Event)VS_IuReleaseReqPs_NoResourceAvailable(U599_17)(Event) VS_IuReleaseReqPs_OamIntervention(U599_2)(Event)VS_IuReleaseReqPs_OtherCause(U577_8)(Event) VS_IuReleaseReqPs_PhyChnReestabFail(U599_21)(Event)VS_IuReleaseReqPs_RadioCnxUeLost(U599_6)(Event) VS_IuReleaseReqPs_ReleaseDueToUtranGeneratedReason(U599_14)(Event)VS_IuReleaseReqPs_RepeatedIntegrityCheckFailure(U599_4)(Event) VS_IuReleaseReqPs_T305Expiry(U599_18)(Event)VS_IuReleaseReqPs_T360Expiry(U599_12)(Event) VS_IuReleaseReqPs_UlRLCErrSRB(U599_9)(Event)VS_IuReleaseReqPs_UlRLCErrTRB(U599_11)(Event) VS_IuReleaseReqPs_UnspecifiedFailure(U599_3)(Event)VS_IuReleaseReqPs_UtranPageFail(U599_20)(Event)
FOA1
FOA2
RRE activation
A new scenario directly linked to
the feature will lead to pegging
the counters IuRelReq.UlRlcErr.
This scenario corresponds
basically to the case where the
cellUpdateConfirm to re-
establish the call is not correctly
received by the mobile this
cause an increase which is not
really a drawback of the RRE
feature as this behaviour where
expected. (AR 1-2211670 closed)
Significant decreased of the DL RLC Error on TRB
Significant decreased of the DL RLC Error on SRB
Significant decreased of the Dl RLC Error on TRB
-
21 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
Increase of the IuReleaseReqPS_UeGeneratedSignallingConnectionRelease
After the RRE feature activation, the IuReleaseReqPS with cause
UeGeneratedSignallingConnectionRelease has abnormally increase.
Assumptions : it is assumes that this is spontaneous release of the UE during the
RRC Re-establishment phase.
more study needed
R R E _ P S _ d r o p _ c a u s e s _ C R - R N C :( L Y O N T R I O 2 ) - 0 5 / 0 1 / 2 0 0 9 T o 0 7 / 0 1 / 2 0 0 9
0
2 0 0 0 0
4 0 0 0 0
6 0 0 0 0
8 0 0 0 0
1 0 0 0 0 0
1 2 0 0 0 0
1 4 0 0 0 00
5
/
0
1
/
2
0
0
9
0
5
/
0
3
/
2
0
0
9
0
5
/
0
5
/
2
0
0
9
0
5
/
0
7
/
2
0
0
9
0
5
/
0
9
/
2
0
0
9
0
5
/
1
1
/
2
0
0
9
0
5
/
1
3
/
2
0
0
9
0
5
/
1
5
/
2
0
0
9
0
5
/
1
7
/
2
0
0
9
0
5
/
1
9
/
2
0
0
9
0
5
/
2
1
/
2
0
0
9
0
5
/
2
3
/
2
0
0
9
0
5
/
2
5
/
2
0
0
9
0
5
/
2
7
/
2
0
0
9
0
5
/
2
9
/
2
0
0
9
0
5
/
3
1
/
2
0
0
9
0
6
/
0
2
/
2
0
0
9
0
6
/
0
4
/
2
0
0
9
0
6
/
0
6
/
2
0
0
9
0
6
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/
2
0
0
9
0
6
/
1
0
/
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0
0
9
0
6
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1
2
/
2
0
0
9
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1
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2
0
0
9
0
6
/
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0
0
9
0
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8
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0
0
9
0
6
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2
0
/
2
0
0
9
0
6
/
2
2
/
2
0
0
9
0
6
/
2
4
/
2
0
0
9
0
6
/
2
6
/
2
0
0
9
0
6
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2
8
/
2
0
0
9
0
6
/
3
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2
0
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9
E
v
e
n
t
V S _ Iu R e le a s e R e q P s _ U e G e n e r a t e d S ig n a llin g C o n n ec t io n R e le a s e ( U 5 9 9 _ 5 ) ( E v e n t )
RRE activation
FOA2
-
22 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
Las tR adioL ink Dropped_R L007_C R_P s (UR L007_C R_P s ) (E vent)
0
5 0 0
1 0 0 0
1 5 0 0
2 0 0 0
2 5 0 0
3 0 0 0
3 5 0 0
06/01
/2009
06/03
/2009
06/05
/2009
06/07
/2009
06/09
/2009
06/11
/2009
06/13
/2009
06/15
/2009
06/17
/2009
06/19
/2009
06/21
/2009
06/23
/2009
06/25
/2009
06/27
/2009
06/29
/2009
Las tRad ioLink D ropped_R L007_CR_P s (URL007_CR_P s ) (E ven t)
Number of call dropped due to Last Radio Link in AS which failed (CS, PS)
VS.RadioLinkDroppedLastRadioLink is pegged only in case the RL drop occurs for the only RL present in the ActiveSet(the primary RL).
If a RL drop occurs for the primary RL and there is no other leg in the ActiveSet, both VS.RadioLinkFailureIndication and VS.RadioLinkDroppedLastRadioLinkare incremented
If a RL drop occurs for the primary RL and there is another leg in the ActiveSet, a new cell will be elected as Primary. In this case, only VS.RadioLinkFailureIndication is pegged
LastRadioLinkDropped_RL007_CR_CsVoice(URL007_CR_CsVoice) (Event)
0
100
200
300
400
500
600
700
800
06/01
/2009
06/03
/2009
06/05
/2009
06/07
/2009
06/09
/2009
06/11
/2009
06/13
/2009
06/15
/2009
06/17
/2009
06/19
/2009
06/21
/2009
06/23
/2009
06/25
/2009
06/27
/2009
06/29
/2009
LastRadioLinkDropped_RL007_CR_CsVoice(URL007_CR_CsVoice) (Event)
RRE activation
RRE activation
The RRE feature is efficient to
save the last Radio Link for CS and
PS service
VS.RadioLinkDroppedLastRadioLink :
Number of calls that have been dropped
because the last RL of the Active Set has
failed. Trigger on reception of a NBAP RL
Failure Indication while there was only this
RL in Active Set.
FOA2
FOA2
-
23 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
R ad io L ink Failu re D istribution
0
20000
40000
60000
80000
100000
120000
140000
160000
180000
200000
06/01
/2009
06/03
/2009
06/05
/2009
06/07
/2009
06/09
/2009
06/11
/2009
06/13
/2009
06/15
/2009
06/17
/2009
06/19
/2009
06/21
/2009
06/23
/2009
06/25
/2009
06/27
/2009
06/29
/2009
V S _R adioL ink F ailu re Indic a t ion_Trans portR es ourc es Unava ilab le(U 18_2) (E vent)V S _R adioL ink F ailu re Indic a t ion_S y nc hronis a t ionF ailure(U18_4) (E vent)V S _R adioL ink F ailu re Indic a t ion_O therC aus es (U18_8)(E vent)V S _R adioL ink F ailu re Indic a t ion_O am Intervent ion(U 18_0) (E vent)V S _R adioL ink F ailu re Indic a t ion_N otE noughR es ourc esF orC m (U18_6) (E vent)V S _R adioL ink F ailu re Indic a t ion_InvalidCm S ett ings (U 18_1) (E vent )V S _R adioL ink F ailu re Indic a t ion_Im aD efens e(U 18_7)(E vent)V S _R adioL ink F ailu re Indic a t ion_H ardw areF a ilu re(U 18_5) (E vent)V S _R adioL ink F ailu re Indic a t ion_C ontro lP roc es s ingO verload(U 18_3) (E vent )
NBAP Radio Link Failure distribution
RRE activation
The number of Radio Link Failure Indication remains stable.
The setting applied at the activation does not modified the Radio Link Failure
time detection.
Probably some tuning is needed for the UL loss synchronization detection.
-
24 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
Cell Update Success Rate vs Nbr_Cell_Update_Rejects
The Cell Update Success Rate is significantly degraded after the activation of RRC
Re-Establishment feature mainly due to the increase of Cell Update Reject with
cause Unknown URNTI
Cell Update Success Rate vs NbrCellUpdateRejects
65.00%
70.00%
75.00%
80.00%
85.00%
90.00%
95.00%
05/01
/2009
05/04
/2009
05/07
/2009
05/10
/2009
05/13
/2009
05/16
/2009
05/19
/2009
05/22
/2009
05/25
/2009
05/28
/2009
05/31
/2009
06/03
/2009
06/06
/2009
06/09
/2009
06/12
/2009
06/15
/2009
06/18
/2009
06/21
/2009
06/24
/2009
06/27
/2009
06/30
/2009
0
5000
10000
15000
20000
25000
VS _NbrCellUpdateRejec ts_A bortedByA NewerCellUpdate(U902_2) (E vent) V S _NbrCellUpdateRejec ts_FachCacFailure(U902_4) (E vent)VS _NbrCellUpdateRejec ts_Incorrec tM essage(U902_1) (E vent) V S _NbrCellUpdateRejec ts_Other(U902_3) (E vent)VS _NbrCellUpdateRejec ts_UnknownURNTI(U902_0) (E vent) CellUpdateS uccessRate_RL019_CR(URL019_CR) (% )
-
25 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
N b r C e l l U p d a te d is t r ib u t io n
0
2 0 0 0 0
4 0 0 0 0
6 0 0 0 0
8 0 0 0 0
1 0 0 0 0 0
1 2 0 0 0 0
1 4 0 0 0 00
6
/
0
1
/
2
0
0
9
0
6
/
0
2
/
2
0
0
9
0
6
/
0
3
/
2
0
0
9
0
6
/
0
4
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2
0
0
9
0
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2
0
0
9
0
6
/
0
6
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2
0
0
9
0
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0
7
/
2
0
0
9
0
6
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2
0
0
9
0
6
/
0
9
/
2
0
0
9
0
6
/
1
0
/
2
0
0
9
0
6
/
1
1
/
2
0
0
9
0
6
/
1
2
/
2
0
0
9
0
6
/
1
3
/
2
0
0
9
0
6
/
1
4
/
2
0
0
9
0
6
/
1
5
/
2
0
0
9
0
6
/
1
6
/
2
0
0
9
0
6
/
1
7
/
2
0
0
9
0
6
/
1
8
/
2
0
0
9
0
6
/
1
9
/
2
0
0
9
0
6
/
2
0
/
2
0
0
9
0
6
/
2
1
/
2
0
0
9
0
6
/
2
2
/
2
0
0
9
0
6
/
2
3
/
2
0
0
9
0
6
/
2
4
/
2
0
0
9
0
6
/
2
5
/
2
0
0
9
0
6
/
2
6
/
2
0
0
9
0
6
/
2
7
/
2
0
0
9
0
6
/
2
8
/
2
0
0
9
0
6
/
2
9
/
2
0
0
9
0
6
/
3
0
/
2
0
0
9
V S _ N b rC e llU p d a te s _ C e llR e s e le c tio n(U 9 0 1 _ 0 ) (E ve nt) V S _ N b rC e llU p d a te s _ P a g ing R e s p o ns e (U 9 0 1 _ 3 ) (E ve nt)V S _ N b rC e llU p d a te s _ P e rio d ic C e llU p d a te (U 9 0 1 _ 1 ) (E ve nt) V S _ N b rC e llU p d a te s _ R a d io L ink F a i lu re (U 9 0 1 _ 5 ) (E ve nt)V S _ N b rC e llU p d a te s _ R e e nte re d S e rvic e A re a (U 9 0 1 _ 4 ) (E ve nt) V S _ N b rC e llU p d a te s _ R lc U nre c o ve ra b le E rr(U 9 0 1 _ 6 ) (E ve nt)V S _ N b rC e llU p d a te s _ U p link D a ta T ra ns m is s io n(U 9 0 1 _ 2 ) (E ve nt)
Cell Update distribution
RRE activation
The RRC Re-establishment
introduce new scenario with
Cell Update RLFI and
RlcUnrecoverableError
Significant increase of the occurrence
handle by the RRE feature
C ell U p date (trigg er by R R E featu re)
0
5000
10000
15000
20000
25000
06/01
/2009
06/03
/2009
06/05
/2009
06/07
/2009
06/09
/2009
06/11
/2009
06/13
/2009
06/15
/2009
06/17
/2009
06/19
/2009
06/21
/2009
06/23
/2009
06/25
/2009
06/27
/2009
06/29
/2009
V S _NbrCellUpdates_RadioLinkFailure(U901_5) (E vent)V S _NbrCellUpdates_Rlc UnrecoverableE rr(U901_6) (E vent)
FOA2
FOA2
-
26 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
N b r C e l l U p d a t e R e j e c t d i s t r i b u t i o n
0
5 0 0 0
1 0 0 0 0
1 5 0 0 0
2 0 0 0 0
2 5 0 0 00
6
/
0
1
/
2
0
0
9
0
6
/
0
3
/
2
0
0
9
0
6
/
0
5
/
2
0
0
9
0
6
/
0
7
/
2
0
0
9
0
6
/
0
9
/
2
0
0
9
0
6
/
1
1
/
2
0
0
9
0
6
/
1
3
/
2
0
0
9
0
6
/
1
5
/
2
0
0
9
0
6
/
1
7
/
2
0
0
9
0
6
/
1
9
/
2
0
0
9
0
6
/
2
1
/
2
0
0
9
0
6
/
2
3
/
2
0
0
9
0
6
/
2
5
/
2
0
0
9
0
6
/
2
7
/
2
0
0
9
0
6
/
2
9
/
2
0
0
9
V S _ N b r C e llU p d a te R e je c ts _ U n k n o w n U RN T I( U 9 0 2 _ 0 ) ( E v e n t)V S _ N b r C e llU p d a te R e je c ts _ O th e r ( U 9 0 2_ 3 ) ( E v e n t)V S _ N b r C e llU p d a te R e je c ts _ In c o r r e c tM es s a g e ( U 9 0 2 _ 1 ) ( E v e n t)V S _ N b r C e llU p d a te R e je c ts _ F a c h C a c F a ilu r e ( U 9 0 2 _ 4 ) ( E v e n t)V S _ N b r C e llU p d a te R e je c ts _ A b o r te d B y AN e w e r C e llU p d a te ( U 9 0 2 _ 2 ) ( E v e n t)
Cell Update Reject distribution (1/2)
RRE activation
Significant increase of the Cell Update reject due to UnknownUrNTIand Other causes
RRE activation draws new scenario with the mobile sending much more cell
updates while t314/t315 is running.
Here are two new scenario which explain this increase:
Cellupdatrejects.UnknowURNTI=> Basically receipt of cell update after RNC has cleared the
call or UE arrive on a new UTRAN and his U-RNTI is unknown
Cellupdaterejects.Other => Basically receipt of cell Update in the middle of RNC clearing the
call.
A way of improvement could be to decrease the T315 timer
-
27 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
Cell Update Reject distribution (2/2)
The number of Cell Update
Reject due to Incorrect Message
increase significantly on the two
FOA network, it has not been
tracked by an AR.
This error occurs when there is
an integrity issue on the Cell
Update message received from
the mobile
VS_NbrCellUpdateRejects_IncorrectMessage(U902_1) (Event)
0
100
200
300
400
500
600
0
6
/
0
1
/
2
0
0
9
0
6
/
0
2
/
2
0
0
9
0
6
/
0
3
/
2
0
0
9
0
6
/
0
4
/
2
0
0
9
0
6
/
0
5
/
2
0
0
9
0
6
/
0
6
/
2
0
0
9
0
6
/
0
7
/
2
0
0
9
0
6
/
0
8
/
2
0
0
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/
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2
/
2
0
0
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3
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0
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4
/
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0
0
9
0
6
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5
/
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0
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9
0
6
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2
6
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0
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0
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9
VS_NbrCellUpdateRejects_IncorrectMessage(U902_1) (Event)
on (VERNC02) - from 04/01/2009 to 06/02/2009
0
200
400
600
800
1000
1200
1400
04/01
/2009
04/04
/2009
04/07
/2009
04/10
/2009
04/13
/2009
04/16
/2009
04/19
/2009
04/22
/2009
04/25
/2009
04/28
/2009
05/01
/2009
05/04
/2009
05/07
/2009
05/10
/2009
05/13
/2009
05/16
/2009
05/19
/2009
05/22
/2009
05/25
/2009
05/28
/2009
05/31
/2009
E
v
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VS_NbrCellUpdateRejects_IncorrectMessage(U902_1)
RRE activation
RRE activation
FOA2
FOA1
-
28 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
What are the impacts of the Cell Update success rate degradation?
The VS_RRC_RBReconfigSucc counter is incremented whenever the RNC receives :
either a RADIO BEARER RECONFIGURATION COMPLETE message
or a 'UTRAN Mobility Information Confirm' for Ues in Cell_FACH only -indicating successful cell reselection interrupting RB reconfiguration procedure from the UE in response to the RNC sending a RADIO_BEARER_RECONFIGURATION REQUEST message.
R adio B earer R econfigurations d istribution
0
200000
400000
600000
800000
1000000
1200000
05/01
/2009
05/04
/2009
05/07
/2009
05/10
/2009
05/13
/2009
05/16
/2009
05/19
/2009
05/22
/2009
05/25
/2009
05/28
/2009
05/31
/2009
06/03
/2009
06/06
/2009
06/09
/2009
06/12
/2009
06/15
/2009
06/18
/2009
06/21
/2009
06/24
/2009
06/27
/2009
06/30
/2009
V S_RRC_RB ReconfigA tt(U2672) (Event)V S_RRC_RB ReconfigSucc (U2674) (E vent)
Very small decrease of the daily RB_Reconf_Succ (-3%) but the number of attempts are also
decrease in the same proportion
The amount of successful RB
Reconfiguration remains stable
The Cell Update degradation due to, mainly, the increase of Cell Update Reject with cause
Unknown URNTI is not really a drawback as there is no other impact on the main KPI
FOA2
-
29 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
Improvement on the 3G 2G mobility
A small decrease of the number of call drop due to 3G to 2G is noted after the
RRE activation.
D r o p p e d _ d u e _ 3 G 2 G H H O _ C R - R N C : L Y O N T R IO 2 - 0 5 /0 1 /2 0 0 9 T o 0 7 /0 1 /2 0 0 9
9 0 . %
9 1 . %
9 2 . %
9 3 . %
9 4 . %
9 5 . %
9 6 . %
9 7 . %
9 8 . %
9 9 . %
1 0 0 . %
05/01
/2 009
05/04
/2 009
05/07
/2 009
05/10
/2 009
05/13
/2 009
05/16
/2 009
05/19
/2 009
05/22
/2 009
05/25
/2 009
05/28
/2 009
05/31
/2 009
06/03
/2 009
06/06
/2 009
06/09
/2 009
06/12
/2 009
06/15
/2 009
06/18
/2 009
06/21
/2 009
06/24
/2 009
06/27
/2 009
06/30
/2 009
E
v
e
n
t
0
5 0
1 0 0
1 5 0
2 0 0
2 5 0
3 0 0
3 5 0
4 0 0
4 5 0
N u m b e r O fC S C a l l s D r o p p e d D u e T o 3 G 2 G H H O _ H O 3 G 2 G 0 2 4 _ C _ C s ( U H O 3 G 2 G 0 2 4 _ C _ C s ) ( E ve n t )R a t e o f3 G 2 G D e t e c t i o n L e a d in g T o S u c c e s s fu lH H O _ IM C T A 0 0 6 _ C _ A la r m C s ( U IM C T A 0 0 6 _ C _ A l a r m C s ) ( % )
RRE activation
FOA2
-
30 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
5UA6 RRC Re-Establishment Monitoring
Optimization proposal (T313/ N313)
FOA2 customer
-
31 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
RLC (NodeB-RNC) - SRB DL/UL Step 1 Step 2MaxDat 40 40 40Polling Timer 120 120 120prohibitedStatus Timer unset unset unsetMinimum time to reset RLC DL/UL = MaxDat*PollingTimer (s) 4.8 s 4.8 s 4.8 sN313 (Maximum number of successive "out of sync" received from L1 each 10ms) 200 200 200T313 (starts when the UE detects consecutive N313 "out of sync" indication from L1) 3 2 1N315 (Maximum number of successive "in sync" received from L1 during T313 is activated) 1 1 1Minimum time to detect a loss of synchronisation in DL = 10ms*N313 + T313 (s) 5 s 4 s 3 sNoutsyncInd (frames) 256 256 256NinsyncInd (frames) 1 1 1Trlfailure (ms) 2500 2500 2500Minimum time to detect a loss of synchronisation in UL = 10ms*NoutsyncInd + Trlfailure (s) 5,06 s 5,06 s 5,06 sTimer_ASU (s) 7 7 7UE TimersT314 (for CS starts when the criteria for radio link failure are fulfilled) 8 s 8 s 8 sT315 (for PS starts when the criteria for radio link failure are fulfilled) 180 s 180 s 180 sRNC TimersrrcReestCSMaxAllowedTimer 8 s 8 s 8 srrcReestPSMaxAllowedTimer 180 s 180 s 180 s
RRE Optimization
Optimization proposal
The optimization will consist in detect more quickly a synchronisation failure in Downlink by decreasing the couple (N313, T313).
In fact, If the detection time is longer in UL than in DL, then the UE will detect the most of time the synchro issue. It is better if the UE detect firstly (DL detection) because the UE is alone to detect loss of synchronization whereas in UL detection case (in SHO case) 2 nodeBare able to detect a loss of synchro DL synchro detection is less robust than UL synchrodetection.
The time detection in UL can be higher than DL time detection.
rrcReestCSMaxAllowedTimer and rrcReestPSMaxAllowedTimer > Max (Time to lose UL
synchronisation ; Time to lose DL synchronisation)
-
32 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
RRE Optimization
CS call drop observation after T313 modifications
At this stage of the optimization, we cannot conclude on the efficiency of the
(T313, N313) proposal. A longer observation period is necessary to state on these
values.
The CS CDR stay at the level obtain after RRE feature activation
CS_Call_drop_overview : LYONTRIO2 - 05/01/2009 To 07/01/2009
0.%
0.1%
0.2%
0.3%
0.4%
0.5%
0.6%
0.7%
0.8%
0.9%
1.%0
5
/
0
1
/
2
0
0
9
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/
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0
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0
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1
1
/
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9
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0
9
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1
/
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0
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9
0
5
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/
2
0
0
9
0
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/
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/
2
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0
9
0
5
/
2
7
/
2
0
0
9
0
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2
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/
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0
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9
0
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1
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9
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/
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2
/
2
0
0
9
0
6
/
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4
/
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0
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9
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0
9
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0
9
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/
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0
9
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0
9
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9
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/
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0
0
9
0
6
/
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0
/
2
0
0
9
0
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/
2
2
/
2
0
0
9
0
6
/
2
4
/
2
0
0
9
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6
/
2
6
/
2
0
0
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0
6
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2
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/
2
0
0
9
0
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3
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2
0
0
9
E
v
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0
500
1000
1500
2000
2500IuAbnormalReleaseRequest_IU008_R_CsVoice(UIU008_R_CsVoice)(Event)CallDropRate_IU007_R_CsVoice(UIU007_R_CsVoice)(%)
RRE activationT313: 3 2
T313: 2 1
-
33 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
CS_drop_causes - RNC: LYONTRIO2 - 05/01/2009 To 07/01/2009
0
2000
4000
6000
8000
10000
05/01
/2009
05/03
/2009
05/05
/2009
05/07
/2009
05/09
/2009
05/11
/2009
05/13
/2009
05/15
/2009
05/17
/2009
05/19
/2009
05/21
/2009
05/23
/2009
05/25
/2009
05/27
/2009
05/29
/2009
05/31
/2009
06/02
/2009
06/04
/2009
06/06
/2009
06/08
/2009
06/10
/2009
06/12
/2009
06/14
/2009
06/16
/2009
06/18
/2009
06/20
/2009
06/22
/2009
06/24
/2009
06/26
/2009
06/28
/2009
06/30
/2009
E
v
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t
VS_IuReleaseReqCs_AbnormalConditionTimerRelocExpiry(U576_5)(Event) VS_IuReleaseReqCs_ConnectionWithNodeBLost(U576_10)(Event)VS_IuReleaseReqCs_DlRLCErrSRB(U576_7)(Event) VS_IuReleaseReqCs_FailureInTheRadioInterfaceProcedure(U576_13)(Event)VS_IuReleaseReqCs_NoRemainingRAB(U576_12)(Event) VS_IuReleaseReqCs_NoResourceAvailable(U576_14)(Event)VS_IuReleaseReqCs_OamIntervention(U576_0)(Event) VS_IuReleaseReqCs_OtherCause(U576_6)(Event)VS_IuReleaseReqCs_RadioConnectionWithUeLost(U576_4)(Event) VS_IuReleaseReqCs_ReleaseDueToUtranGeneratedReason(U576_11)(Event)VS_IuReleaseReqCs_RepeatedIntegrityCheckFailure(U576_2)(Event) VS_IuReleaseReqCs_T360Expiry(U576_9)(Event)VS_IuReleaseReqCs_UeGeneratedSignallingConnectionRelease(U576_3)(Event) VS_IuReleaseReqCs_UlRLCErrSRB(U576_8)(Event)VS_IuReleaseReqCs_UnspecifiedFailure(U576_1)(Event)
RRE Optimization
CS drop causes observation after T313 modifications
The main gain after the T313 modification is the decrease of the pattern Cs call
drop with cause DL_RLC_Err_SRB. More observation is needed.
RRE activationT313: 3 2
T313: 2
The gain after the T313 modification is the decrease of CS call drop with cause
DL_RLC_Err_SRB
-
34 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
Feature behaviour on CS trigger (DL/UL RL Failure, Other) after modification
R RE_C S_Performance_D lR lFailure - RN C: LYON TR IO2 - 05/01/2009 To 07/01/2009
0
20
40
60
80
100
120
140
05/01
/2009
05/04
/2009
05/07
/2009
05/10
/2009
05/13
/2009
05/16
/2009
05/19
/2009
05/22
/2009
05/25
/2009
05/28
/2009
05/31
/2009
06/03
/2009
06/06
/2009
06/09
/2009
06/12
/2009
06/15
/2009
06/18
/2009
06/21
/2009
06/24
/2009
06/27
/2009
06/30
/2009
E
v
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V S_RrcReEs tablishm entS uccess_CS DLRLFail(U58_8)(E vent)V S_RrcReEs tablishm entA ttempt_CS DLRLFail(U57_8)(E vent)
RRE_CS_Performance_Other- RNC: LYONTRIO2 - 05/01/2009 To 07/01/2009
0
5
10
15
20
25
30
35
40
45
50
05/01
/2009
05/04
/2009
05/07
/2009
05/10
/2009
05/13
/2009
05/16
/2009
05/19
/2009
05/22
/2009
05/25
/2009
05/28
/2009
05/31
/2009
06/03
/2009
06/06
/2009
06/09
/2009
06/12
/2009
06/15
/2009
06/18
/2009
06/21
/2009
06/24
/2009
06/27
/2009
06/30
/2009
E
v
e
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VS_RrcReEstablishmentSuccess_CS_Other(U58_6)(Event)VS_RrcReEstablishmentAttempt_CS_Other(U57_6)(Event)
RRE_CS_Performance_UlRlFailure- RNC: LYONTRIO2 - 05/01/2009 To 07/01/2009
0
50
100
150
200
250
300
350
400
450
500
05/01
/2009
05/04
/2009
05/07
/2009
05/10
/2009
05/13
/2009
05/16
/2009
05/19
/2009
05/22
/2009
05/25
/2009
05/28
/2009
05/31
/2009
06/03
/2009
06/06
/2009
06/09
/2009
06/12
/2009
06/15
/2009
06/18
/2009
06/21
/2009
06/24
/2009
06/27
/2009
06/30
/2009
E
v
e
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t
VS_RrcReEstablishmentSuccess_CSULRLFail(U58_7)(Event)VS_RrcReEstablishmentAttempt_CSULRLFail(U57_7)(Event)
These triggers (DLRlFailure and Other) are more detected
after the T313 modifications, we can expect some
improvement on the CS retainability KPI
This increase of DL attempted RRC re-
establishment is as expected
-
35 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
R R E_PS_C all_drop R N C : LYON TR IO2 - 05/01/2009 To 07/01/2009
.%
1.%
2.%
3.%
4.%
5.%
6.%
05/01
/2009
05/03
/2009
05/05
/2009
05/07
/2009
05/09
/2009
05/11
/2009
05/13
/2009
05/15
/2009
05/17
/2009
05/19
/2009
05/21
/2009
05/23
/2009
05/25
/2009
05/27
/2009
05/29
/2009
05/31
/2009
06/02
/2009
06/04
/2009
06/06
/2009
06/08
/2009
06/10
/2009
06/12
/2009
06/14
/2009
06/16
/2009
06/18
/2009
06/20
/2009
06/22
/2009
06/24
/2009
06/26
/2009
06/28
/2009
06/30
/2009
E
v
e
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t
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
IuA bnorm alReleaseRequest_IU008_R_P s(UIU008_R_Ps )(E vent)IuA bnorm alReleaseRequest_IU008_R_HSDP A(UIU008_R_HSDPA)(Event)CallDropRate_IU007_R_HSDP A(UIU007_R_HSDP A)(% )CallDropRate_IU007_R_P s(UIU007_R_Ps )(% )
RRE activationT313: 3 2
T313: 2 1
No improvement of the PS CDR after the T313 modification, the PS retainability
kpi follow his normal evolution.
RRE Optimization
PS drop rate observation after T313 modifications
-
36 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
RRE_PS_Performance_DlRlFailure_CR - RNC: LYONTRIO2 ( LYONTRIO2 ) - 05/01/2009 To 07/01/2009 (Working Zone: TRIO2 - Medium)
0
20
40
60
80
100
120
140
160
180
200
05/01
/2009
05/03
/2009
05/05
/2009
05/07
/2009
05/09
/2009
05/11
/2009
05/13
/2009
05/15
/2009
05/17
/2009
05/19
/2009
05/21
/2009
05/23
/2009
05/25
/2009
05/27
/2009
05/29
/2009
05/31
/2009
06/02
/2009
06/04
/2009
06/06
/2009
06/08
/2009
06/10
/2009
06/12
/2009
06/14
/2009
06/16
/2009
06/18
/2009
06/20
/2009
06/22
/2009
06/24
/2009
06/26
/2009
06/28
/2009
06/30
/2009
E
v
e
n
t
VS_RrcReEstablishmentSuccess_PSDLRLFail(U58_2)(Event)VS_RrcReEstablishmentAttempt_PSDLRLFail(U57_2)(Event)
RRE_PS_Performance_DlRlcUnrecoverError_CRv - RNC: LYONTRIO2 ( LYONTRIO2 ) - 05/01/2009 To 07/01/2009 (Working Zone: TRIO2 - Medium)
0
50
100
150
200
250
300
350
400
450
500
550
0
5
/
0
1
/
2
0
0
9
0
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/
0
3
/
2
0
0
9
0
5
/
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5
/
2
0
0
9
0
5
/
0
7
/
2
0
0
9
0
5
/
0
9
/
2
0
0
9
0
5
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1
1
/
2
0
0
9
0
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1
3
/
2
0
0
9
0
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1
5
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2
0
0
9
0
5
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1
7
/
2
0
0
9
0
5
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1
9
/
2
0
0
9
0
5
/
2
1
/
2
0
0
9
0
5
/
2
3
/
2
0
0
9
0
5
/
2
5
/
2
0
0
9
0
5
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2
7
/
2
0
0
9
0
5
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2
9
/
2
0
0
9
0
5
/
3
1
/
2
0
0
9
0
6
/
0
2
/
2
0
0
9
0
6
/
0
4
/
2
0
0
9
0
6
/
0
6
/
2
0
0
9
0
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0
8
/
2
0
0
9
0
6
/
1
0
/
2
0
0
9
0
6
/
1
2
/
2
0
0
9
0
6
/
1
4
/
2
0
0
9
0
6
/
1
6
/
2
0
0
9
0
6
/
1
8
/
2
0
0
9
0
6
/
2
0
/
2
0
0
9
0
6
/
2
2
/
2
0
0
9
0
6
/
2
4
/
2
0
0
9
0
6
/
2
6
/
2
0
0
9
0
6
/
2
8
/
2
0
0
9
0
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/
3
0
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0
0
9
E
v
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VS_RrcReEstablishmentSuccess_PSDLRlcUnrecoverErr(U58_4)(Event)VS_RrcReEstablishmentAttempt_PSDLRlcUnrecoverErr(U57_4)(Event)
R R E _P S _P e r fo rmance _O the r_C R - R N C : L Y O N T R IO 2 ( L Y O N T R IO 2 ) - 05 /01 /2009 T o 07/01/2009 (W o rkin g Zo n e : T R IO 2 - M e d iu m)
0
1 0 0
2 0 0
3 0 0
4 0 0
5 0 0
6 0 0
7 0 0
8 0 0
9 0 0
0
5
/
0
1
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VS _ R rc R e E s ta b l is h m e n tS u cc e s s _ P S _ O th e r(U 5 8 _ 0 )(E ve n t)VS _ R rc R e E s ta b l is h m e n tAtte m p t_ P S _ O th e r(U 5 7 _ 0 )(E ve n t)
R R E_PS_Performance_U lR lFailure_C R - R N C : LYON TR IO2 ( LYON TR IO2 ) - 05/01/2009 To 07/01/2009 (Working Zone: TR IO2 - Medium)
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VS_RrcReEstablishmentSuccess_PSULRLFail(U58_1)(Event)VS_RrcReEstablishmentA ttem pt_PSULRLFail(U57_1)(Event)
These triggers (DLRlFailure and Other) are more detected
after the T313 modifications, we can expect some
improvement on the CS retainability KPI
Feature behaviour on PS trigger (DL/UL RL Failure, Other) after modification
This increase of DL attempted RRC re-
establishment is as expected
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37 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
0
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/2009
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/2009
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VS_NbrCellUpdates_CellReselection(U901_0) (Event) VS_NbrCellUpdates_PagingResponse(U901_3) (Event)VS_NbrCellUpdates_PeriodicCellUpdate(U901_1) (Event) VS_NbrCellUpdates_RadioLinkFailure(U901_5) (Event)VS_NbrCellUpdates_ReenteredServiceArea(U901_4) (Event) VS_NbrCellUpdates_RlcUnrecoverableErr(U901_6) (Event)VS_NbrCellUpdates_UplinkDataTransmission(U901_2) (Event)
The activation of RRE feature has modified as expected the Cell Update
distribution.
The T313 decrease should allow to detect quicker DL failure synchronization and
then trigger more often Cell Update procedures
RRE activation
T313: 3 2
T313: 2 1Feature behaviour on Cell Update procedure after modification
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38 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
6UA6 CS and PS RRC Re-Establishment
Assessment
Conclusion
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39 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
Conclusion
The introduction of RRC Re-Establishment feature show significant improvement
on the CS call drop rate (-20%) and on the PS call drop rate (-50%).
An optimization campaign on the (N313, T313) parameters has been to improve
the DL loss synchronisation detection. The results and the observations obtained
until now do not allow to conclude yet on the proposal settings.
Some rooms of improvements still exist:
Improve the Cell Update success rate by decreasing the amount of Cell Update
Reject (mainly URNTI cause): this should be done with T315.
Explain and improve the increase the number of drop due to
UeGeneratedSignallingConnectionRelease appeared after RRC Re-establishment
feature
Improve the UL loss synchronization detection : (NInsync , NoutSync)
Feature can be activated on Live Network
-
40 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
www.alcatel-lucent.comwww.alcatel-lucent.com
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41 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
Backup
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42 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
UA6.0 CS and PS RRC Connection Re-establishment
UL Radio Link Failure
Uplink Radio Link monitoring is performed by the NodeB, using the following algorithm:
When the radio link set is in-sync:
- Node B starts timer T_RLFAILURE after receiving N_OUTSYNC_IND consecutive out-of-sync indications from the layer 1.
- Node B stops and reset timer T_RLFAILURE upon receiving successive N_INSYNC_IND in-sync indications from the layer 1.
- If T_RLFAILURE expires, Node B triggers the RL Failure procedure and indicates to the Controlling RNC which radio link set
is out-of-sync.
When the radio link set is out-of-sync:
- After receiving N_INSYNC_IND successive in-sync indications from the layer 1, Node B triggers the RL Restore procedure
and indicate which radio link set has re-established synchronisation.
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43 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
Reminder : RRE Optimization
UL Radio Link Failure
The following tables summarize the parameters
used in radio link synchronisation
tRlFailure = 2500 ms, nOutSyncInd = 256, nInSyncInd = 1
RL Failure is then detected after 2.5 seconds of UL synchronization loss (usually longer than RLC failure detection).
In DL, the UE has the same mechanism based on N313 and T313.
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44 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
Reminder : Loss of Uplink Synchronization detection
UE NodeB RNC CN
1. Detection that the RL is in Out-of- Sync State 2. Reception of NoutsyncInd=256 consecutive frame
Timer TRLFailureNode B = 2,5 sec is trigger
No
Timer expiredTRL Failure Node B
Reception of NinsyncInd = 1 trames In Sync
Link is synchronized => TimerTRLFailureNode B is reset+ RL Restore Indication procedure islaunched
Yes
tRlFailure = 2500 ms, nOutSyncInd = 256, nInSyncInd = 1
UL synchronization loss detection =
T_RLFAILURE+(N_OUT_OF_SYNC_INDx10)=2500+(256x10)= 5.06s
RRC Cell Update (Cause RL Failure or RLC)
See previous slide for the call flow continuation
-
45 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
RL Failure - Counters
When the RNC receives a NBAP RADIO_LINK_FAILURE from the nodeB, the counter
VS.RadioLinkFailureIndication is pegged in the cell where the failure occurred.
The possible causes are:
OamIntervention: when the cell becomes unavailable after OAM intervention
InvalidCmSettings: if several CM patterns are activated and if some CM gaps overlap or
more than one CM gap are present in radio frame
TransportResourcesUnavailable: Iub AAL2 CID already in use by another RL
ControlProcessingOverload: BTS DSP processing overload
SynchronisationFailure: loss of UL radio synchronization with UE
HardwareFailure: unexpected BBU/DSP error
NotEnoughResourcesForCm: lack of radio resource at CM activation, after RL reconf
commit
ImaDefense: RL deleted by the BTS to save Iub bandwidth in case of PCM loss
OtherCauses: all other causes
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46 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
Reminder : RRE Optimization
DL Radio Link Failure
Detection of DL radio link failures is performed by the UE, using the following algorithm:
In cell DCH state, after receiving N313 consecutive "out of sync" indications from layer 1 for the established DPCCH, the UE start timer T313 :
- upon receiving N315 successive "in sync" indications from layer 1, the UE stops and resets timer T313.
- If T313 expires, radio Link Failure condition is fulfilled. UE sends a Cell Update message with cause Radio Link failure
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47 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
Reminder : Loss of Downlink Synchronization detection
UE NodeB RNC CN
1. Out Sync state detection: 2. Reception of 200 trames N313 with bad quality: 200 *
10ms = 100 msec3. Dclenchement du Timer T313 (3 sec)
No
T313 Expires (5 sec)
If N315 frames is received successvely in Sync = 1*10 ms = 10 ms
Stop Timer T313 => No dropDL Link Synchronized
Yes
T313 = 3s, N313 = 200, N315 = 1
DL synchronization loss detection =
(N313 * 10) + T313 = (200 * 10 ms) + 3s = 5s
RRC Cell Update (Cause RL Failure or RLC)
See previous slide for the call flow continuation
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48 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
Counters for RLC Unrecoverable errors detection
The counter VS.RlcUnrecoverableError is pegged in case of DL RLC error
detection, at ReferenceCell level. It is screened by Granted Combined Maximum
Ul Dl Bit rate.
RabSrb is used for all types or Signaling Radio Bearers (standalone or associated
to a TRB)
RabCsConv are not used because Cs traffic uses RLC transparent mode and RLC
error of the associated Srb will peg VS.RlcUnrecoverableError.RabSrb
The counter VS.NbrCellUpdates.RlcUnrecoverableError (#901) is pegged when the
Ue has detected an UL RLC unrecoverable error and reported it to the RNC in a
RRC Cell Update message.
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49 | UA6 RRC Re-Establishment CS and PS | April 2009 Alcatel-Lucent 2008, d.r., XXXXX
RL Drop counters
VS.RadioLinkDroppedLastRadioLink is pegged only in case the RL drop occurs
for the only RL present in the ActiveSet (the primary RL). This counter is
available at ReferenceCell level and is screened by DlAsConfId.
If a RL drop occurs for the primary RL and there is no other leg in the
ActiveSet, both VS.RadioLinkFailureIndication and
VS.RadioLinkDroppedLastRadioLink are incremented
If a RL drop occurs for the primary RL and there is another leg in the
ActiveSet, a new cell will be elected as Primary. In this case, only
VS.RadioLinkFailureIndication is pegged
The counter VS.NbrCellUpdates.RadioLinkFailure is pegged when the Ue has
detected a DL RL synchronization failure and reported it to the RNC in a
RRC Cell Update message.
