Fast Return to LTE Improvement

KTS LR14.2W 170715 Fast Return to LTE improvement Sep 8th 2015

NEA/TIS – Jean-Noël CHARNEAU/Boubacar COULIBALY/Sophie PIEKAREC

1 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

1. Feature Description 2. Interactions with other features and Upgrade rules 3. Activation Strategy in ORF Network 4. Assessment – Fast Return Time 5. Assessment - Performance 6. Lessons learned from Call Trace 7. Limitations 8. Conclusion ANNEX – Tests ANNEX - AR1-5624148 analysis 2 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

1

Feature Description

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Feature Objectives  Avoid detecting CSFB when UE is redirected by eNodeB to UTRAN for another reason than CSFB o Radio problem (entering coverage alarm, below serving floor) o Offload reason (reactive load control, preventive load control)

 Detect CSFB when UE provides both “Pre-redirection Info” and “CSFB Indication” IE in RRC CONNECTION REQUEST

4 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

170715 is based on UA8.1 134661 • Purpose of UA8.1 PM134661 is to send UE back to LTE at CS call completion after RNC has detected that UE has connected for a CSFB reason • CSFB is detected by RNC if « Pre-redirection Info » is not present in RRC CONNECTION REQUEST 3GPP 9.4+ : UE shall not include « Pre-redirection Info » in RRC CONNECTION REQUEST if redirected by LTE CSFB detection is based on the absence of « Pre-Redirection info » IE at RRC connection If UE is LTE capable: CsfbDetection is set to TRUE

VS.CsfbDetectionInRrcConn++

Detection of fake CSFB If UE redirected by LTE for radio or load reason Side effect: UE Fast Returned to LTE if CS call is setup

5 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

170715 added value • CSFB is detected by RNC if optional « CSFB Indication » IE is present in RRC CONNECTION REQUEST 3GPP 9.11+: UE should include « CSFB Indication » in RRC CONNECTION REQUEST if redirected by LTE for CSFB UE CSFB detection is based on the presence of « CSFB Indication » IE at RRC connection

If UE is LTE capable:

Risk of non detection of true CSFB if UE not supporting « CSFB Indication »

CsfbDetection is set to TRUE

Side effect: UE not Fast Returned to LTE at CS call release VS.CsfbDetectionInRrcConn++

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Impact on CSFB Detection at RNC LTE -> 3G redirections

CSFB

Non-CSFB (radio, offload)

LTE 3G

No Pre-redirection

Pre-redirection Info

CSFB Indication

CSFB Indication (C)

No CSFB Indication (B)

No CSFB Indication

No Pre-redirection Info

Pre-redirection Info

CS Speech call (A) No CS Speech call

CSFB Detection based on

« Pre-redirection Info » not present

« CSFB Indication » present Call is not a CS fallback, and 134661 feature mistakenly fast returns the UE UE does not support“CSFB Indication”, and 170715 does not fast return the UE UE provides both “Pre-redirection Info” & “CSFB Indication”, and 170715 fast returns the UE where 134661 does not 7 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Feature Pros & Cons  

Gain

UE Types [1]

Pre134661 CSFB Redirectio (csfbDetectionM Indication n Info ethod= presence present CsfbDeduction)

1 Yes

2

170715 (csfbDetectionM Comments ethod= CsfbIndication)

No

Redirect

Redirect

Common CSFB scenario of R9 UE. Most of R8 UE performs also this CSFB scenario.

Yes

No Redirect

Redirect

Few cases observed for both R8 and R9 UE CSFB.

3 supports CSFB indication

No

Redirect

No Redirect

Not a CSFB scenario. Common scenario for non-CSFB redirections. Rare cases of speech call setup after a redirection from LTE has been performed for a non-CSFB cause (radio, ofload). Main improvement is regarding interpretation of CSFB detection counter.

Yes

No Redirect

No Redirect

Not a CSFB scenario. Speech call setup scenario for UE camping on 3G.

No 4 5

6

Pros

does not support CSFB indication

No

Redirect

No Redirect

Yes

No Redirect

No Redirect

No

Common scenario for non-CSFB redirections of R8 UE not supporting CSFB indication IE. Rare cases of R9 UE CSFB. Still observed for a significant part of R8 UE CSFB. Not a normal CSFB scenario. Speech call setup scenario for UE camping on 3G. Can correspond to a CSFB performed in poor radiio conditions.

Cons Gain is expected if feature is activated for R9 UE only (csfbDeductionAndIndication).

[1] Actual Support of “CSFB Indication” IE is not know by RNC since it is an Optional R9 IE. Field observation showed that some R9 UE don’t support it but also some R8 UE support it. 8 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Two steps activation of the feature • “CSFB Indication” optional IE has been introduced in R9 version 11 therefore lots of R8 UE currently on the field don’t support it • Feature is designed to be able to activate feature in two steps  for R9+ UE only in a 1st step (the only step assessed in ORF FA)  for any UE in a 2nd step (all UE supporting CSFB Indication IE) New parameter

1st step 2nd step

CSFB Detection at RNC R8 UE R9+ UE "Pre-redirection "Pre-redirection csfbDeduction Info" not present Info" not present csfbDeductionAndInd "Pre-redirection "CSFB Indication" ication Info" not present present "CSFB Indication" "CSFB Indication" csfbIndication present present csfbDetectionMethod

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2

Interactions with other features and Upgrade rules

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PM170715 interactions with other features UA8 134661 Fast Return to LTE at CS call completion Introduces the capability to redirect LTE capable UE at the end of a CSFB that was detected either as an RRCbased CSFB (at RRC CONNECTION without UE providing the Pre-redirection Info IE) or as a PS HO-based CSFB (at incoming 4G->3G RELOCATION REQUEST with Radio Network Layer Cause Extension IE = “CS Fallback triggered”). The PM170715 adds supplementary options on top of it.  Required Feature. Strong interaction. UA8 108661 LTE to UMTS PS HO and cell reselection enhancements Introduces the capability to detect an incoming PS HO-based CSFB call as a CS speech call that is setup in a TmaxDelayForCsCallEstablishment time period after an incoming 4G->3G RELOCATION REQUEST with Radio Network Layer Cause Extension IE = “CS Fallback triggered” has been successfully performed.  Recommended Feature. No interaction but gain of 170715 is less when 108661 is enabled as most of the CSFB scenario will be PS HO-based and 170715 brings improvement for RRC-based CSFB only. UA8 89858 iMCTA Enhanced - Redirection to LTE sub-feature Introduces the capability to trigger a redirection to LTE on AO downsize from DCH to FACH or xPCH.  Recommended Feature. No interaction but of interest if 134661 was not triggered due to non-detection of CSFB. UA8 89857 iMCRA Step 2 Introduces the capability to redirect to LTE an LTE capable UE at RRC CONNECTION with UE providing the Preredirection Info IE.  Recommended Feature for LTE capable UE camping on 3G and connecting from Idle mode for PS service. Interaction with 170715 in the sense that in LR14.2W RNC does not trigger redirection to LTE if UE provides 11 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED. CSFB Indication IE in RRC CONNECTION REQUEST

At upgrade to LR14.2W, the new parameter will get the following value : RadioAccessService::csfbDetectionMethod = CsfbDeduction

12 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

3

Activation Strategy in ORF Network

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The NodeB cluster included 13 sites upgraded in LR14.2W and 6 sites that were still in LR13.3W but feature was activated on these 19 sites as it is managed at RNC level. # 1 2 3 4 5 6 7 8 9

RNC ORLEANSV 1 ORLEANSV 1 ORLEANSV 1 ORLEANSV 1 ORLEANSV 1 ORLEANSV 1 ORLEANSV 1 ORLEANSV 1 ORLEANSV 1

eNodeB CHATEAUROUX_OMELON CHATEAUROUX_MADRON

Release LR14.2W LR14.2W

LR14.2W CHATEAUROUX_ZI_EST CHATEAUROUX_CHRISTOP LR14.2W HE CHATEAUROUX_ETATS_UNI LR14.2W S CHATEAUROUX_DEOLS MONTS_RIPAULT

LR14.2W LR14.2W

14 15 16 17 18 19

ORLEANSV1 CHATEAUROUX_CENTRE CHATEAUROUX_CITE_GD_CH ORLEANSV1 AMPS CHATEAUROUX_CITE_ST_JEA ORLEANSV1 N ORLEANSV1 CHATEAUROUX_FT ORLEANSV1 ISSOUDUN_BASQUE_SFR ORLEANSV1 ISSOUDUN_BEL_AIR

LR14.2W ISSOUDUN_HOPITAL CHATEAUROUX_PINGAUDIE LR14.2W 14 RE COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

LR13.3W LR13.3W LR13.3W LR13.3W LR13.3W LR13.3W

UA8 feature 134661 « Fast Return to LTE at CS call completion » was already activated at LR14.2W upgrade on the FA cluster. Activation of 170715 « Fast Return to LTE improvement » was performed by changing the csfbDetectionMethod RNC parameter Object RNC

FDDCell

Instance ORLEANSV1

Cluster cells

Parameter

Old value

New value

csfbDetectionMethod (class 3)

CsfbDeduction

CsfbDeductionAndIndi cation

isSib19Allowed true isReleaseAndRedirectionForCsFbAllowe true d sib19Enable true

Object

Instance

Parameter

FDDCell

Cluster cells

CellSelectionWithPriorityProfileId

true true true

CellSelectionWithPriorityProfiles/ eUtraTargetDlCarrierFrequencyArfcn 0 eUtraTargetFrequencyMeasurementBa EUtranFrequencyAndPriorityInfoL ndwidth EUtranFrequencyAndPriorityI ist/0 nfoList CellSelectionWithPriorityProfiles/ eUtraTargetDlCarrierFrequencyArfcn 15 0 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED. eUtraTargetFrequencyMeasurementBa

Old value CellProfiles/0 CellSelection WithPriorityPr ofile/0 3000

New value CellProfiles/0 CellSelection WithPriorityPr ofile/0 3000

100

100

6400

6400

4

Assessment – Fast Return Time

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Fast Return Time check (1/3) Live tests were performed in order to compute the 3G->LTE Fast Return Time and compare it to the value commited with ORF. Two kinds of tests were performed : • TC11:CSFB-Release-FR-To-LTE when csfbDetectionMethod = csfbDeductionAndIndication Start a CS call on 4G, UE will fallback to 3G, when releasing the CS the UE Fast Returns to LTE • TC14:CSFB-PS-Release-FR-To-LTE when csfbDetectionMethod=csfbDeductionAndIndication Start a CS call on 4G, UE will fallback to 3G, add a PS call on 3G, release CS, UE Fast Returns to LTE while PS traffic is ongoing on LTE

Two kinds of UE were used : −Samsung N4 : R9 supporting CSFB Indication IE −Samsung S3 : R8 not supporting CSFB Indication IE

Fast Return time were measured from two different perspectives:  User perspective, preferred by ORF, time between Disconnect message on 3G and Tracking Area Update Complete on LTE  Network perspective, preferred by ALU, time between last RRC Connection Release message on 3G and Tracking Are Update Request on LTE 17 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Fast Return Time check (2/3)

Fast Return Time ALU

Fast Return Time ORF

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Fast Return Time check (3/3) All tests were compliant with the commited ORF Fast Return Time of max 2s : Results

134661+ 170715 Activate d

FR Tests

UE

NodeB SW

Redirection FR Time ORANGE (s)

Redirection FR Time ALU(s)

TC11

Samsung N4

LR14.2W

1,341

0,253

TC14

Samsung N4

LR14.2W

1,422

0,302

TC11

Samsung N4

LR13.3W

1,351

0,332

TC14

Samsung N4

LR13.3W

1,410

0,319

TC11

Samsung S3

LR14.2W

1,425

0,208

TC14

Samsung S3

LR14.2W

1,417

0,240

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5

Assessment - Performance

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• Improvement of Fast Return rate thanks to the decrease of the difference between number of CSFB detected and number of Fast Return trigerred, because LTE->3G redirections of R9+ UE for non-CSFB causes are not anymore detected as CSFB by RNC

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• Fast Rate improvement is correlated with difference between CSFB Detected and Fast Return

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• New screenings of CSFB Detected from “CSFB Indication” IE are pegged (R9 UE CSFB)

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• New counters are pegged, CS Voice RAB Setup Success Rate is very good • No CS Voice RAB setup for CSFB in Relocation as PS HO LTE->3G is not activated

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• New counters are pegged, CS Voice RAB Drop Rate is very good • No CS Voice RAB drop for CSFB in Relocation as PS HO LTE->3G is not activated

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• First CS RRC Connection Success Rate globally stable with more variations after activation

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• CS Call Setup Success Rate globally stable with more variations after activation

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• First PS RRC Connection Success Rate globally stable with a temporary degradation on march 12-15 period

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• PS Call Setup Success Rate globally stable with less variations after activation

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• CS Call Drop globally stable with more variations after activation

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• PS Call Drop globally stable

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• DL PS Traffic globally stable the week after activation and increased after vacation (march 9)

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• UL PS Traffic globally stable the week after activation and increased after vacation (march 9)

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• HSDPA Throughput globally stable after activation with more stability and an increase after vacation time (march 10)

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• HSUPA Throughput globally stable

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7

Lessons learned from Call Trace

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RNC call trace  CTg trace on RNC ORLEANSV1 on Thursday 12th March evening (8pm)  CS Speech calls traced for any UE type  Focus on the 1346 LTE capable UE speech calls  Analysis of these calls based on the combination of o “Pre-redirection Info” IE o “CSFB Indication” IE

 Goals were to assess :  Distribution of R8/R9 LTE capable UE  Percentage of R9 UE not supporting « CSFB Indication » IE  Percentage of R9 UE calls where both IE are provided by UE  Percentage of R8 UE supporting « CSFB Indication » IE 37 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Distribution of R8/R9 LTE capable UE  From all LTE capable UE speech calls : 87% R9 - 13% R8 1168 R8 (86.78%)

R8 UE (86.78%)

178 R9 (13.22%)

R9 UE (13.22%)

1346 calls

Assumption for R8/R9 distribution of LTE->3G redirections 38 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Percentage of R9 UE not supporting « CSFB Indication » IE  2% of R9 UE not supporting « CSFB Indication » (2/92) • corresponding to 1.5% of CSFB detected (2/146)

1346 calls

R9 UE 178 calls 109 IMSI

CSFB Detection based on

Pre-redirection Info 146 calls 92 IMSI

« Pre-redirection Info » not present

CSFB Indication 144 calls 90 IMSI

CSFB Indication 2 calls 2 IMSI

-2

« CSFB Indication » present

 Non-detection of the 2 CSFB above is mitigated by the new detection of some other CSFB scenario (see next page) 39 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

R9 UE calls where both IE are provided by UE  4 calls observed with « Pre-redirection Info » and « CSFB Indication » IE provided by UE • these 4 calls mitigate the 2 non-CSFB detections 32 Pre-redirection Info 1346 calls « Pre-redirection Info » not present

R9 UE 178 calls 146 Pre-redirection Info

« CSFB Indication » present

4 CSFB Indication 28 CSFB Indication

+ 4

144 CSFB Indication 2 CSFB Indication

-2

 This call scenario is probably due to engaged CSFB as per UE perspective but for which the LTE->3G redirection is not properly completed • RRC CONNECTION RELEASE with « redirectedCarrierInfo » not received by UE 40 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

R8 UE supporting « CSFB Indication » IE  Lots of R8 UE do support R9 « CSFB Indication » IE : 75% of Detected CSFB • still 25% or R8 UE do not (243/990)

178 Pre-redirection Info 1346 calls « Pre-redirection Info » not present

R8 UE 1168 calls 990 Pre-redirection Info

« CSFB Indication » present

4 CSFB Indication

+ 4

174 CSFB Indication 747 CSFB Indication 243 CSFB Indication

- 243

 Network is not mature enough to activate 170715 feature for R8 UE as well 41 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

8

Limitations

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Feature limitations – Poor LTE coverage  In case of poor LTE coverage or LTE cells loaded, probability of a failure during the redirection to LTE may increase o 3G->LTE RRC redirection being triggered in blind mode (not measurement based) o If no suitable cell on indicated LTE frequency(ies) is found within 10s, an attempt to camp on any suitable cell on any other available LTE frequencies is applicable. o If no LTE coverage is available, UE can spend up to 20s searching for LTE, before coming back to 3G. For such areas, reselection should be preferred, avoiding a potential 20s period when UE cannot be paged nor perform traffic.

 A way to avoid this would be to deactivate the feature on 3G cells in areas with poor LTE coverage  « Redirection to LTE on AO Downsize » can also be disabled on those cells 43 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Feature limitations – Non global activation of Fast Return  In case Fast Return to LTE feature (134661) is not activated on the whole RNS, some UE, the ones having performed a CSFB, will not be redirected to LTE if CS call completion takes place after a Primary Cell Change to a cell where FRtoLTE is not activated  This will degrade the Fast Return Success Rate

 A way to avoid this would be to activate the feature on all 3G cells of same RNS for which we know that LTE coverage is good enough on the same serving area  As for LR13.3W, FRtoLTE is still not triggered after Iur mobility o Inter-RNS Primary Cell Change o SRNS relocation scenario These two scenarios will be covered by LR15.3W feature 179215 Fast Return to LTE Enhancements 44 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

9

Conclusion

45 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Conclusion UE traces have shown that feature behaves as expected New counters were pegged Feature Pros & Cons : + no CSFB detection for non-CSFB LTE->3G redirection => no Fast Return if subsequent non-CSFB CS call ends on 3G + Fast Return if both « Pre-redirection Info » & « CSFB Indication » are provided by UE

- CSFB not detected and Fast Return not triggered if UE does not provide « CSFB Indication » : • R8 UE : mitigated by choosing CsfbDeductionAndIndication instead of CsfbIndication • R9 UE : limited by the low quantity of such UE and availability of « Redirection to LTE on AO Downsize » feature 46 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

ANNEX – Tests

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Test Activities • Lab Tests at CEVENNES from 5th to 19th February 2015 • Live Tests at CHATEAUROUX from 2nd to 14th March 2015 • Three mobiles have been used o Two Pre-Rel9 UE  SAMSUNG S4 during Lab Tests  SAMSUNG S3 during Live Tests  Those UE are not supporting the optional « CSFB Indication » IE o One Rel9 UE  SAMSUNG Note4 during Lab/Live Tests  This UE is supporting the « CSFB Indication » IE • Note about the live tests number : o Tests 3, 7, 11, 14 and 16 have been executed 2 times  First time with LR14.2W NodeB sites  Second time with LR13.3W NodeB sites 48 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Test List (1/2)   Test1

Test Objective Verify that csfbDetectionMethod parameter can be set to different values via WO and online modification CSFB-Release-FR-To-LTE when csfbDetectionMethod = csfbDeduction -> Pre-Rel9 MS Test2 Start a CS call from 4g, UE will fallback to 3G, then when releasing CS call, UE Fast Returns to LTE CSFB-Release-FR-To-LTE when csfbDetectionMethod = csfbDeductionAndIndication -> Pre-Rel9 MS Test3 Start a CS call from 4g, UE will fallback to 3G, then when releasing CS call, UE Fast Returns to LTE Test4 Verify that Pre-REL9 UE does not FR to LTE after CSFB when csfbDetectionMethod=csfbIndication verify that all non-cSFBIndication UE can not be identified as CSFB and will not fast return to LTE CSFB Test5 when csfbDetectionMethod=csfbIndication and a PS call is added on UMTS verify that all non-cSFBIndication UE can not be identified as CSFB and will not fast return to LTE CSFB Test6 when csfbDetectionMethod=csfbIndication and PS relocation is performed. PS-then-CSFB-Release-FR-To-LTE when csfbDetectionMethod = csfbDeductionAndIndication -> Pre-Rel9 MS Start a PS call from 4G, add a CS call, UE will fallback to 3G, release CS call, UE Fast Returns to LTE while PS traffic is Test7 ongoing on LTE CSFB-PS-Release-FR-To-LTE when csfbDetectionMethod = csfbDeduction -> Pre-Rel9 MS Start a CS call from 4G, UE will fallback to 3G, start a PS call, release CS call, UE Fast Returns to LTE Test8 while PS traffic is ongoing on LTE CSFB-PS-Release-FR-To-LTE when csfbDetectionMethod = csfbDeductionAndIndication -> Rel9 MS Start a CS call from 4G, UE will fallback to 3G, start a PS call, release CS call, UE Fast Returns to LTE Test9 while PS traffic is ongoing on LTE CSFB-PS-Release-FR-To-LTE when csfbDetectionMethod = csfbDeductionAndIndication -> Pre-Rel9 MS Start a CS call from 4G, UE will fallback to 3G, start a PS call, release CS call, UE Fast Returns to LTE Test9 bis while PS traffic is ongoing on LTE Test10 Verify that Post-REL9 UE always redirects to LTE after CSFB when csfbDetectionMethod=csfbDeduction CSFB-Release-FR-To-LTE when csfbDetectionMethod = csfbDeductionAndIndication -> Rel9 MS Test11 Start a CS call on 4G, UE will fallback to 3G, when releasing the CS the UE Fast Returns to LTE 49 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

LAB OK

LIVE  

OK OK OK

OK  

OK

 

OK

 

OK

OK

OK

 

OK

OK

  OK

OK  

OK

OK

Test List (2/2)   Test12

Test Objective Verify that Post-REL9 UE always redirects to LTE after CSFB when csfbDetectionMethod=csfbIndication CSFB-PS-Release-FR-To-LTE when csfbDetectionMethod=csfbDeduction -> Rel9 MS Start a CS call on 4G, UE will fallback to 3G, add a PS call on 3G, release CS, UE Fast Returns to LTE Test13 while PS traffic is ongoing on LTE CSFB-PS-Release-FR-To-LTE when csfbDetectionMethod=csfbDeductionAndIndication -> Rel9 MS Start a CS call on 4G, UE will fallback to 3G, add a PS call on 3G, release CS, UE Fast Returns to LTE Test14 while PS traffic is ongoing on LTE CSFB-PS-Release-FR-To-LTE when csfbDetectionMethod=csfbIndication -> Rel9 MS Start a CS call on 4G, UE will fallback to 3G, add a PS call on 3G, release CS, UE Fast Returns to LTE Test15 while PS traffic is ongoing on LTE PS-CSFB-Release-FR-To-LTE when csfbDetectionMethod=csfbDeductionAndIndication -> Rel9 MS Start with a PS call on 4G, then make a CS call as well, UE will fallback to 3G, when releasing this CS, UE Fast Test16 Returns to LTE while PS traffic is ongoing on LTE PS-CSFB-Release-FR-To-LTE when csfbDetectionMethod=csfbIndication -> Rel9 MS Start with a PS call on 4G, then make a CS call as well, UE will fallback to 3G, when releasing this CS, UE Fast Test17 Returns to LTE while PS traffic is ongoing on LTE PS-CSFB-Release-FR-To-LTE when csfbDetectionMethod=csfbDeduction -> Rel9 MS Start with a PS call on 4G, then make a CS call as well, UE will fallback to 3G, when releasing this CS, UE Fast Test18 Returns to LTE while PS traffic is ongoing on LTE Verify that Post-REL9 UE does not FR to LTE when a PS call is redirected to 3G due to lost of Test19 radio contact with LTE cause and CS call is then made Verify that Pre-REL9 UE does not FR to LTE when a PS call is redirected to 3G due to lost of Test20 radio contact with LTE cause and CS call is then made FR_Time_C1 Compute the Fast Return To LTE Time: Repeat 7 times the test TC11 and do the test TC14 12 times SAMSUNG Note4 FR_Time_C2 Compute the Fast Return To LTE Time: Repeat 7 times the test TC11 and do the test TC14 12 times SAMSUNG S3 50 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

LAB OK

LIVE  

OK OK

OK

OK OK

OK

OK

 

OK OK

 

OK    

  OK OK

Test on Live Network • Live tests objectives were to o Execute some functional test cases on the live context o Compute the Fast Return Time

• The Fast Return Time Computation has been done with the following hypothesis: Test11 & 14 were repeated several times, UE logs collected and information on 3G-4G transition time was extracted

• Fast Return time were measured from two different perspectives:  User perspective, preferred by ORF, time between Disconnect message on 3G and Tracking Area Update Complete on LTE  Network perspective, preferred by ALU, time between last RRC Connection Release message on 3G and Tracking Are Update Request on LTE LR14.2W NodeB tests have been done on Chateauroux Christophe site LR13.3W NodeB tests have been done on Chateauroux FT site Several roaming drives have been done in Chateauroux with both Samsung N4 and S3 51 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Local Field Configuration Impacts •It has been observed on the FA area that some FRtoLTE were not triggered after CSFB in the following scenario :  LTE to 3G CSFB was performed on a 3G site A  CSFB was detected and counted as such on site A  UE moved to another site when connected to 3G  CS call was completed on a 3G site B where FRtoLTE was not triggered

•FRtoLTE was not triggered due to one of the following causes :  3G site B coverage was not overlapped by sufficient LTE coverage  Fast Return feature was not activated on 3G site B

•Consequence was a bigger difference at NodeB cluster level between o the number of CSFB detected o the number of Fast Return triggered 52 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

Fast Return Time Computation SAMSUNG Note4 on LR14.2W NodeB Sites (1/2) • Fast Return time ORF commitment of maximum 2 seconds has been met for each particular test case. Results

170715 Activate d

FR Tests

Time "Disconnect" Time"TAU Complete"

Redirection FR Time Time last "RRC Redirection FR Time Time"TAU Request" ORANGE (s) Connection Release" ALU(s)

TC11 - Try1

15:07:37:390

15:07:38:933

1.443

15:07:38:095

15:07:38:351

0.256

TC11- Try2

15:09:23:351

15:09:24:729

1.378

15:09:24:077

15:09:24:346

0.269

TC11- Try3

15:15:11:126

15:15:12:500

1.374

15:15:11:729

15:15:12:013

0.284

TC11- Try4

15:17:22:676

15:17:24:047

1.371

15:17:23:228

15:17:23:493

0.265

TC11- Try5

15:19:25:260

15:19:26:446

1.186

15:19:25:702

15:19:25:941

0.239

TC11- Try6

15:21:15:086

15:21:16:387

1.301

15:21:15:665

15:21:15:926

0.261

TC11- Try7

15:23:13:190

15:23:14:524

1.334

15:23:13:737

15:23:13:985

0.198

Moyenne TC11-7

1.341

53 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

0.253

Fast Return Time Computation SAMSUNG Note4 on LR14.2W NodeB Sites (2/2) Results

170715 Activat ed

FR Tests

Time "Disconnect"

Time"TAU Complete"

Time"TAU Request"

Redirection FR Time ALU(s)

TC14- Try1

15:34:00:076

15:34:01:832

1.756

15:34:00:921

15:34:01:148

0.227

TC14- Try2

15:34:29:261

15:34:30:510

1.249

15:34:29:868

15:34:30:100

0.232

TC14- Try3

15:35:33:961

15:35:35:711

1.75

15:35:34:599

15:35:35:269

0.67

TC14- Try4

15:37:28:125

15:37:29:390

1.265

15:37:28:696

15:37:28:975

0.279

TC14- Try5

15:38:22:327

15:38:23:774

1.447

15:38:22:913

15:38:23:292

0.379

TC14- Try6

15:38:57:903

15:38:59:294

1.391

15:38:58:424

15:38:58:750

0.326

TC14- Try7

15:39:32:045

15:39:34:114

2.069

15:39:33:444

15:39:33:730

0.286

TC14- Try8

15:40:15:007

15:40:16:151

1.144

15:40:15:491

15:40:15:723

0.232

TC14- Try9

15:40:46:342

15:40:47:688

1.346

15:40:46:970

15:40:47:244

0.274

TC14- Try10

15:41:30:649

15:41:31:783

1.134

15:41:31:139

15:41:31:350

0.211

TC14- Try11

15:42:23:426

15:42:24:592

1.166

15:42:23:996

15:42:24:227

0.231

TC14- Try12

15:43:47:443

15:43:48:794

1.351

15:43:47:993

15:43:48:264

0.271

Moyenne TC14-12

Redirection FR Time Time last "RRC ORANGE (s) Connection Release"

1.422 54 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

0.302

Fast Return Time Computation SAMSUNG Note4 on LR13.3W NodeB Sites Results

170715 Activat ed

FR Tests

Time "Disconnect"

Time"TAU Complete"

Time"TAU Request"

Redirection FR Time ALU(s)

TC11 - Try1

12:57:09:291

12:57:10:503

1.212

12:57:09:858

12:57:10:091

0.243

TC11- Try2

13:00:24:352

13:00:25:688

1.436

13:00:24:886

13:00:25:238

0.352

TC11- Try3

13:03:29:806

13:03:31:087

1.281

13:03:30:302

13:03:30:561

0.259

TC11- Try6

13:11:49:983

13:11:51:445

1.462

13:11:50:533

13:11:51:017

0.484

TC11- Try7

13:14:32:405

13:14:33:769

1.364

13:14:32:995

13:14:33:315

0.32

Moyenne TC11-5

Redirection FR Time Time last "RRC ORANGE (s) Connection Release"

1.351

0.332

TC14- Try1

13:18:37:336

13:18:38:593

1.157

13:18:37:935

13:18:38:168

0.235

TC14- Try8

13:26:45:856

13:26:47:589

1.733

13:26:46:358

13:26:46:833

0.475

TC14- Try9

13:27:10:283

13:27:11:696

1.413

13:27:10:966

13:27:11:286

0.32

TC14- Try10

13:27:42:534

13:27:43:871

1.337

13:27:43:219

13:27:43:465

0.246

Moyenne TC14-4

1.41

55 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

0.319

Fast Return Time Computation SAMSUNG S3 on LR14.2W NodeB Sites (1/2) Results

170715 Activate d

FR Tests

Time "Disconnect" Time"TAU Complete"

Redirection FR Time Time last "RRC Redirection FR Time Time"TAU Request" ORANGE (s) Connection Release" ALU(s)

TC11 - Try1

11:12:37:633

11:12:39:045

1.412

11:12:38:394

11:12:38:647

0.253

TC11- Try2

11:19:14:977

11:19:16:089

1.112

11:19:15:674

11:19:15:780

0.106

TC11- Try3

11:21:51:712

11:21:53:320

1.608

11:21:52:498

11:21:52:692

0.194

TC11- Try4

11:25:00:761

11:25:02:291

1.53

11:25:01:671

11:25:01:838

0.167

TC11- Try5

11:27:55:954

11:27:57:256

1.302

11:27:56:643

11:27:56:857

0.214

TC11- Try6

11:31:26:034

11:31:27:472

1.438

11:31:26:874

11:31:27:048

0.274

TC11- Try7

11:34:24:288

11:34:25:862

1.574

11:34:25:226

11:34:25:474

0.248

Moyenne TC11-7

1.425

56 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

0.208

Fast Return Time Computation SAMSUNG S3 on LR14.2W NodeB Sites (2/2) Results

170715 Activat ed

FR Tests

Time "Disconnect"

Time"TAU Complete"

Time"TAU Request"

Redirection FR Time ALU(s)

TC14- Try1

11:42:07:336

11:42:08:786

1.45

11:42:08:051

11:42:08:339

0.288

TC14- Try2

11:42:42:247

11:42:43:578

1.331

11:42:43:034

11:42:43:251

0.217

TC14- Try4

12:13:14:348

12:13:15:833

1.485

12:13:15:120

12:13:15:283

0.163

TC14- Try5

12:13:26:881

12:13:28:789

1.908

12:13:28:334

12:13:28:420

0.086

TC14- Try6

12:13:52:177

12:13:53:539

1.362

12:13:52:870

12:13:53:117

0.86

TC14- Try7

12:14:20:498

12:14:21:923

1.425

12:14:21:306

12:14:21:531

0.225

TC14- Try8

12:14:45:525

12:14:46:918

1.393

12:14:46:263

12:14:46:428

0.165

TC14- Try9

12:15:10:973

12:15:12:365

1.392

12:15:11:695

12:15:11:958

0.263

TC14- Try10

12:15:36:052

12:15:37:434

1.382

12:15:36:980

12:15:37:034

0.054

TC14- Try11

12:15:59:829

12:16:01:132

1.303

12:16:00:550

12:16:00:716

0.166

TC14- Try12

12:16:38:296

12:16:39:452

1.156

12:16:38:884

12:16:39:041

0.157

Moyenne TC14-12

Redirection FR Time Time last "RRC ORANGE (s) Connection Release"

1.417

57 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

0.24

TC14 Call Flow – QXDM trace in Lab (1/12) Using R9 UE SAMSUNG N4 supporting “CSFB Indication” IE

UE starts CSFB

58 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

TC14 Call Flow – QXDM trace in Lab (2/12) Using R9 UE SAMSUNG N4 supporting “CSFB Indication” IE

eNodeB redirects UE to 3G carrier 10786

59 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

TC14 Call Flow – QXDM trace in Lab (3/12) Using R9 UE SAMSUNG N4 supporting “CSFB Indication” IE

UE connects to 3G cell and provides « CSFB Indication » IE in RRC CONNECTION REQUEST

60 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

TC14 Call Flow – QXDM trace in Lab (4/12) Using R9 UE SAMSUNG N4 supporting “CSFB Indication” IE

UE sending CM Service Request for CS speech call setup 61 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

TC14 Call Flow – QXDM trace in Lab (5/12) Using R9 UE SAMSUNG N4 supporting “CSFB Indication” IE

End-to-end voice path is setup

62 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

TC14 Call Flow – QXDM trace in Lab (6/12) Using R9 UE SAMSUNG N4 supporting “CSFB Indication” IE

PDP Ctx activation request for PS call to be setup

63 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

TC14 Call Flow – QXDM trace in Lab (7/12) Using R9 UE SAMSUNG N4 supporting “CSFB Indication” IE

PDP Ctx activated

64 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

TC14 Call Flow – QXDM trace in Lab (8/12) Using R9 UE SAMSUNG N4 supporting “CSFB Indication” IE

UE releases the speech call

65 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

TC14 Call Flow – QXDM trace in Lab (9/12) Using R9 UE SAMSUNG N4 supporting “CSFB Indication” IE

UTRAN Fast Returns the UE to LTE through an RRC Redirection procedure

66 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

TC14 Call Flow – QXDM trace in Lab (10/12) Using R9 UE SAMSUNG N4 supporting “CSFB Indication” IE

UE registers at connection to LTE

67 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

TC14 Call Flow – QXDM trace in Lab (11/12) Using R9 UE SAMSUNG N4 supporting “CSFB Indication” IE

UE connects to LTE for Originating Call setup

68 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

TC14 Call Flow – QXDM trace in Lab (12/12) Using R9 UE SAMSUNG N4 supporting “CSFB Indication” IE

Resumption of suspended EPS bearers

69 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

ANNEX – AR1-5624148 analysis

70 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.

71 COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED.