Fast Return to LTE Improvement

(1)

KTS LR14.2W

170715 Fast Return to LTE improvement

Sep 8

th

2015

(2)

Agenda

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

(3)

Feature Description

(4)



_{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

(5)

• 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

170715 is based on UA8.1 134661

If UE is LTE capable: CsfbDetection is set to TRUE

CSFB detection is based on the absence

of

« Pre-Redirection info » IE at RRC

connection

Detection of fake CSFB

If UE redirected by LTE for radio or load

reason

3GPP 9.4+ : UE shall not include « Pre-redirection

Info »

in RRC CONNECTION REQUEST if redirected by LTE

Side effect:

UE Fast Returned to LTE if CS call is setup

(6)

• CSFB is detected by RNC if optional « CSFB Indication » IE is present in RRC

CONNECTION REQUEST

170715 added value

UE CSFB detection is based on the presence of

« CSFB Indication » IE at RRC connection

Risk of non detection of true CSFB

if UE not supporting « CSFB Indication »

3GPP 9.11+: UE should include « CSFB Indication »

in RRC CONNECTION REQUEST if redirected by LTE for

CSFB

Side effect:

UE not Fast Returned to LTE at CS call release

If UE is LTE capable: CsfbDetection is set to TRUE

(7)

Impact on CSFB Detection at RNC

_{LTE -> 3G redirections}

CSFB

Non-CSFB (radio, offload)

No Pre-redirection

Pre-redirection

Info

No Pre-redirection Info

Pre-redirection Info

CSFB Indication

No CSFB Indication

(B)

CSFB Indication

(C)

CSFB Detection based on

« Pre-redirection Info » not present

« CSFB Indication » present

LTE

3G

CS Speech call (A)

No CS Speech call

A- Call is not a CS fallback, and 134661 feature mistakenly fast returns the UE

B- UE does not support“CSFB Indication”, and 170715 does not fast return the UE

(8)

Gain

Feature Pros & Cons

[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.

UE Types [1] CSFB Indication presence Pre-Redirectio n Info present 134661 (csfbDetectionM ethod= CsfbDeduction) 170715 (csfbDetectionM ethod= CsfbIndication) Comments 1 supports CSFB indication

Yes No Redirect Redirect

Common CSFB scenario of R9 UE.

Most of R8 UE performs also this CSFB scenario.

2 _Yes _{No Redirect} _Redirect _{Few cases observed for both R8 and R9 UE CSFB.} 3

No

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.

4

Yes No Redirect No Redirect Not a CSFB scenario. _{Speech call setup scenario for UE camping on 3G.} 5

does not support CSFB indication No

No Redirect No Redirect

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.

6

Yes No Redirect No Redirect

Not a normal CSFB scenario.

Speech call setup scenario for UE camping on 3G. Can correspond to a CSFB performed in poor radiio conditions.

(9)

• “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 1}

st

_{step (the only step assessed in ORF FA)}



_{for any UE in a 2}

nd

_{step (all UE supporting CSFB Indication IE)}

Two steps activation of the feature

1st step

csfbDetectionMethod

CSFB Detection at RNC

R8 UE

R9+ UE

csfbDeduction

"Pre-redirection

Info" not present

"Pre-redirection

csfbDeductionAndInd

ication

Info" not present

"Pre-redirection

"CSFB Indication"

present

csfbIndication

"CSFB Indication"

present

"CSFB Indication"

present

2

nd

_step

(10)

Interactions with other features and Upgrade rules

(11)

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

RRC-based CSFB (at RRC CONNECTION without UE providing the Pre-redirection Info IE) or as a PS HO-RRC-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

Pre-redirection 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

CSFB Indication IE in RRC CONNECTION REQUEST

(12)

Upgrade rules

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

RadioAccessService::csfbDetectionMethod = CsfbDeduction

(13)

Activation Strategy in ORF Network

(14)

FA Cluster

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.

# RNC eNodeB Release 1 ORLEANSV₁ _{CHATEAUROUX_OMELON} LR14.2W 2 ORLEANSV₁ _{CHATEAUROUX_MADRON} LR14.2W 3 ORLEANSV₁ _{CHATEAUROUX_ZI_EST} LR14.2W 4 ORLEANSV₁ CHATEAUROUX_CHRISTOP_HE LR14.2W 5 ORLEANSV₁ CHATEAUROUX_ETATS_UNI_S LR14.2W 6 ORLEANSV₁ _{CHATEAUROUX_DEOLS} LR14.2W 7 ORLEANSV₁ _{MONTS_RIPAULT} LR14.2W 8 ORLEANSV₁ _{ISSOUDUN_HOPITAL} LR14.2W 9 ORLEANSV₁ CHATEAUROUX_PINGAUDIE_RE LR14.2W 10 ORLEANSV₁ _{ARGENTON_VERGER} LR14.2W 11 ORLEANSV₁ _CHEDIGNY LR14.2W 12 ORLEANSV₁ _PERRUSSON LR14.2W 13 ORLEANSV₁ _{ST_GAULTIER} LR14.2W 14 ORLEANSV1 CHATEAUROUX_CENTRE LR13.3W

15 ORLEANSV1CHATEAUROUX_CITE_GD_CH_AMPS LR13.3W

16 ORLEANSV1CHATEAUROUX_CITE_ST_JEA_N LR13.3W

17 ORLEANSV1 CHATEAUROUX_FT LR13.3W

18 ORLEANSV1 ISSOUDUN_BASQUE_SFR LR13.3W

(15)

Feature activation

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 Instance Parameter Old value New value

RNC ORLEANSV1

csfbDetectionMethod (class 3)

CsfbDeduction

CsfbDeductionAndIndi

cation

isSib19Allowed true true

FDDCell Cluster cells

isReleaseAndRedirectionForCsFbAllowe

d true true

sib19Enable true true

Object Instance Parameter Old value New value

FDDCell Cluster cells CellSelectionWithPriorityProfileId

CellProfiles/0 CellSelection WithPriorityPr ofile/0 CellProfiles/0 CellSelection WithPriorityPr ofile/0 EUtranFrequencyAndPriorityI nfoList CellSelectionWithPriorityProfiles/ 0 EUtranFrequencyAndPriorityInfoL ist/0 eUtraTargetDlCarrierFrequencyArfcn 3000 3000 eUtraTargetFrequencyMeasurementBa ndwidth 100 100 CellSelectionWithPriorityProfiles/ 0 EUtranFrequencyAndPriorityInfoL ist/0 eUtraTargetDlCarrierFrequencyArfcn 6400 6400 eUtraTargetFrequencyMeasurementBa ndwidth 50 50

(16)

Assessment – Fast Return Time

(17)

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

(18)

Fast Return Time check (2/3)

Fast Return Time ORF

Fast Return Time ALU

(19)

Fast Return Time check (3/3)

Results FR Tests UE NodeB SW _{Time ORANGE (s)}Redirection FR Redirection FR _{Time ALU(s)}

134661+ 170715 Activate d 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

(20)

Assessment - Performance

(21)

Fast Return performance (1/2)

• 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

(22)

Fast Return performance (2/2)

(23)

CSFB detected ratio Deduction vs Indication

(24)

CS Voice RAB Setup Success Rate on CSFB

• New counters are pegged, CS Voice RAB Setup Success Rate is very good

(25)

CS Voice RAB Drop Rate on CSFB

• New counters are pegged, CS Voice RAB Drop Rate is very good

(26)

Accessibility – CS (1/2)

(27)

Accessibility – CS (2/2)

(28)

Accessibility – PS (1/2)

• First PS RRC Connection Success Rate globally stable with a temporary degradation on

march 12-15 period

(29)

Accessibility – PS (2/2)

(30)

Retainability – CS

(31)

Retainability – PS

(32)

Traffic – PS DL

(33)

Traffic – PS UL

(34)

Quality – HSDPA Throughput

• HSDPA Throughput globally stable after activation with more stability and an increase after

vacation time (march 10)

(35)

Quality – HSUPA Throughput

(36)

Lessons learned from Call Trace

(37)



_{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}

(38)



_{From all LTE capable UE speech calls : 87% R9 - 13% R8}

Distribution of R8/R9 LTE capable UE

1346

calls

1168

R8

(86.78%)

Assumption for R8/R9 distribution of LTE->3G redirections

R8 UE

(86.78%)

R9 UE

(13.22%)

178 R9

(13.22%)

(39)



_{2% of R9 UE not supporting « CSFB Indication » (2/92)}

• corresponding to 1.5% of CSFB detected (2/146)



Non-detection of the 2 CSFB above is mitigated by the new detection of some

other CSFB scenario (see next page)

• also can be non-CSFB LTE->3G redirections followed by a CS speech call setup

Percentage of R9 UE not supporting « CSFB

Indication » IE

1346

calls

- 2

R9 UE

178 calls

109 IMSI

Pre-redirection

Info

146 calls

92 IMSI

CSFB Indication

144 calls

90 IMSI

CSFB Indication

2 calls

2 IMSI

CSFB Detection based on

« Pre-redirection Info » not present

« CSFB Indication » present

(40)



₄

_{calls observed with « Pre-redirection Info » and « CSFB Indication » IE}

provided by UE

• these

4 calls mitigate the

2 non-CSFB detections



_{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

• UE getting out of coverage during engaged CSFB

R9 UE calls where both IE are provided by UE

1346

calls

178 calls

R9 UE

« Pre-redirection Info » not present « CSFB Indication » present

4 CSFB Indication

28 CSFB Indication

144 CSFB Indication

2 CSFB Indication

32 Pre-redirection Info

146 Pre-redirection Info

- 2

+

4

(41)



_{Lots of R8 UE do support R9 « CSFB Indication » IE : 75% of Detected CSFB}

• still 25% or R8 UE do not (243/990)



_{Network is not mature enough to activate 170715 feature for R8 UE as well}

R8 UE supporting « CSFB Indication » IE

1346

calls

R8 UE

1168 calls

4 CSFB Indication

174 CSFB Indication

747 CSFB Indication

243 CSFB Indication

178 Pre-redirection Info

990 Pre-redirection Info

- 243

+

4

« Pre-redirection Info » not present « CSFB Indication » present

(42)

Limitations

(43)



_{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}

(44)



_{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

Feature limitations – Non global activation of

Fast Return

(45)

Conclusion

(46)



_{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

(47)

(48)

Test Activities

•Lab Tests at CEVENNES from 5

th

_{to 19}

th

_{February 2015}

•Live Tests at CHATEAUROUX from 2

nd

_{to 14}

th

_{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}

(49)

Test List (1/2)

Test Objective LAB LIVE

Test1 Verify that csfbDetectionMethod parameter can be set to different values via WO and online modification OK Test2 CSFB-Release-FR-To-LTE when csfbDetectionMethod = csfbDeduction -> Pre-Rel9 MSStart a CS call from 4g, UE will fallback to 3G, then when releasing CS call, UE Fast Returns to LTE OK

Test3

CSFB-Release-FR-To-LTE when csfbDetectionMethod = csfbDeductionAndIndication -> Pre-Rel9 MS

Start a CS call from 4g, UE will fallback to 3G, then when releasing CS call, UE Fast Returns to LTE OK OK Test4 Verify that Pre-REL9 UE does not FR to LTE after CSFB when csfbDetectionMethod=csfbIndication OK Test5

verify that all non-cSFBIndication UE can not be identified as CSFB and will not fast return to LTE CSFB

when csfbDetectionMethod=csfbIndication and a PS call is added on UMTS OK Test6 verify that all non-cSFBIndication UE can not be identified as CSFB and will not fast return to LTE CSFBwhen csfbDetectionMethod=csfbIndication and PS relocation is performed. OK

Test7

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

ongoing on LTE OK OK

Test8

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

while PS traffic is ongoing on LTE OK

Test9

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

while PS traffic is ongoing on LTE OK OK

Test9 bis

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

Test10 Verify that Post-REL9 UE always redirects to LTE after CSFB when csfbDetectionMethod=csfbDeduction OK

Test11

CSFB-Release-FR-To-LTE when csfbDetectionMethod = csfbDeductionAndIndication -> Rel9 MS

(50)

Test Objective LAB LIVE

Test12 Verify that Post-REL9 UE always redirects to LTE after CSFB when csfbDetectionMethod=csfbIndication OK

Test13

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

Test14

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

while PS traffic is ongoing on LTE OK OK Test15

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

Test16

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

Returns to LTE while PS traffic is ongoing on LTE OK OK

Test17

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

Returns to LTE while PS traffic is ongoing on LTE OK

Test18

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

Returns to LTE while PS traffic is ongoing on LTE OK

Test19

Verify that Post-REL9 UE does not FR to LTE when a PS call is redirected to 3G due to lost of

radio contact with LTE cause and CS call is then made OK

Test20 Verify that Pre-REL9 UE does not FR to LTE when a PS call is redirected to 3G due to lost of radio contact with LTE cause and CS call is then made OK 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 OK 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 OK

(51)

•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}

(52)

•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

(53)

Results FR Tests Time "Disconnect" Time"TAU Complete"Redirection FR Time _{ORANGE (s)} _{Connection Release"}Time last "RRC Time"TAU Request" Redirection FR Time _ALU(s)

170715 Activate d 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 0.253

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

(54)

Results FR Tests _"Disconnect"Time Time"TAU Complete" Redirection FR Time _{ORANGE (s)} _{Connection Release"}Time last "RRC Time"TAU _Request" Redirection FR _{Time ALU(s)}

170715 Activat ed 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 1.422 0.302

Fast Return Time Computation

(55)

170715 Activat ed 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 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 0.319

Fast Return Time Computation

(56)

Results FR Tests Time "Disconnect" Time"TAU Complete"Redirection FR Time _{ORANGE (s)} _{Connection Release"}Time last "RRC Time"TAU Request" Redirection FR Time _ALU(s)

170715 Activate d 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 0.208

Fast Return Time Computation

(57)

170715 Activat ed 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 1.417 0.24