Call Drop Improvement Case Study (1)

8/17/2019 Call Drop Improvement Case Study (1)

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Call drop Improvement Security Level: Internal

Call drop improvement case analysis

Summary: In country X, Project Y, during the bad cell KPI analysis, we find so many cells have high call drop rate !ustomer has

given target to improve call drop "#! level target was $%& for !S and !ell level call drop improvement target was $'%(& !S and

$'(& for PS

)larm: before analysis we must chec* current alarm and alarm history, in my case I don+t find any alarm

"-P: "-P chec*ed and I found few sites having high "-P but these sites have high traffic, "-P get poor during the high

utili.ation only

KPI analysis: / from the below KPI analysis, we can see that in my case mostly 0 counter is failed

%/ !all drop due to 12 synchroni.ation3/ !all drop due to 1u #o reply0/ !all drop due to S"4 reset

Solution: - !ell 2evel parameters

UL Syn. Solution: o solve this issue, we can change #I#SY#!I#5 and #61SY#!I#5 parameter 5escription is given

below:/

MML !ommand to change the Parameter MOD CELL

Script 7or 89ampleMOD UCELL: CELLID=XXXXX, NINSYNCIND=1, NOUTSYNCIND=100, TRLFAILURE=100;

NInsyncInd: eaning of this parameter, no of times successive in/sync indications re;uired for the #ode/4 to trigger the radio

lin* recovery process "adio lin* set remains in the initial state until it has received a certain number <the number is defined by

#InsyncInd= of successive in/sync indications from 2%, and then #ode/4 triggers the radio lin* recovery process, which indicates

that the radio lin* set has been synchroni.ed 6nce the radio lin* recovery process is triggered, the radio lin* set is considered to be

in the synchroni.ed state In the radio lin* maintenance process, #InsyncInd is used together with the successive out/of/sync

indication <#61SY#!I#5= counter

Meaning of Parameter: >igher the value is, the stricter the synchroni.ation process becomes, and the more

difficult the synchroni.ation occurs he lower the value is, the easier the synchroni.ation occurs If the lin* ;uality is poor,

a simple synchroni.ation re;uirement leads to waste of the 18 power and increase of uplin* interference5efault ?alue: (6ptimi.ed ?alue: %

NOutsyncInd: -hen the radio lin* set is in the synchroni.ed state, the #ode/4 starts the timer after it receives successive out/of/sync indications of the number defined by #6utsyncInd he #ode/4 shall stop and reset the timer after receiving successive in/

sync indications of the number defined by #InsyncInd -hen the timer e9pires, the #ode/4 triggers the radio lin* failure process,

and indicates which radio lin* set is out/of/sync

Meaning of Parameter: If the value is e9cessively high, the lin* out/of/sync decision is li*ely to happen If the

value is e9cessively low, out/of/sync is not li*ely to happen 4ut if the lin* ;uality is poor, it may result in a waste of the 18

power and increased uplin* interference.5efault ?alue: (@6ptimi.ed ?alue: %@@




!l"ailure: "adio lin* failure timer duration -hen the radio lin* set is in the synchroni.ed state, the #ode/4 starts the timer

after it receives successive out/of/sync indications of the number defined by #6utsyncInd he #ode/4 shall stop and reset the

timer after receiving successive in/sync indications of the number defined by #InsyncInd -hen the timer e9pires, the #ode/4

triggers the radio lin* failure process, and indicates which radio lin* set is out/of/sync

Meaning of parameter: If the value is e9cessively low, there are few chances for the radio lin* to get

synchroni.ed If the value is e9cessively high, the radio lin* failure process is probably delayed, and the downlin*

interference increases5efault ?alue: (@6ptimi.ed ?alue: %@@

Uu No reply:- his counter failed due to poor coverage, to improve this counter we can increase a9 52 "adio 2in* Power for

!S A PS service depend upon re;uirement and condition of cell !ommand to modify 52 "2 power is given below7or 89ample !S %33 call drop issueMOD CELLRLPWR: CELLID=XXXXX C!DOM"I!ID=CS#$OM%IN M"X#I$R"$E=%&&'' !LM%&$LP'!=('RLMI!DLPWR=)%&'*

Note:-"2 ma9 52 power can+t be smaller than "2 min 52 power, if value of this parameter is too much high then

downlin* transmit power on a single radio lin* is too high that means downlin* capacity will be affected If value of thisparameter is set to low value then coverage area of services is decreased that means call drop may increased

In my networ !"rrent #$%"e w$& RLMAXDL'(R=0, !)$n*e+ to RLMAXDL'(R=0, $-ter !)$n*e #$%"e, I &ee t)e

.m/ro#ement .n t)e -$.%"re +"e to U" F$.%e+ !o"nter

Solution: - R!C Level parameter+S!( reset: - 5uring the call drop analysis you will find many call drop reason due to S"4 reset or "4 reset

ainly S"4 reset happened due to poor coverage or issing #eighbor

%= issing #eighbor: if #eighbor cell not configured, from the I6S trace, we can see that it has the problem of #eighbor cell

not configured and drop call occurred easily

7rom the I6S race, the uplin* has been out of synchroni.ation, and from the ""!B8)SB"P", we can see that the downlin* of

cell XXXX is bad, and the 18 has reported the event of %), but from the "#! configuration file, we can+t find the neighbor cell XXXX

whose PS!")4!658 is XXX hen we need to configure the missing neighbors

3= 5ownlin* bad for the cell XXXX, it has many times of S"4C"4 reset and 11 #o reply, we have collected the logs to analy.e the

reason here are many call drop procedures as below: )fter the 18 goes to 7)!> then call drop occurred

-e can see that the 18 want to go to the 5!>, but 7rom the""!B8)SB"P" we can find the 8!C#6 is bad now which means t

hedownlin* is bad, and the 18 would not receive the message of ""!B"4B"8!7D hen the !all 5rop occurred

)nd from the ""!B8)SB"P", we can+t see any other cells that the 18 can detected




ostly 12 and 52 interference create problem and call drop

happened If our "S!P is greater than EF(d4m and )ctive set

8cIo is smaller than E%0 means call drop happened due to down

lin* interference 52 interference may be due to Pilot pollution,

when 0 cell+s meet the handover re;uirement in the coverage

area, the active set replaces the best or the best cell change due

to fluctuations of signals, when the comprehensive ;uality of

active set is bad <8cIo change around E%@ d4=, handover failure

usually casus due the S"4 reset or "4 reset In case of

handover delay the possibility "S!P might be good but 8cIo

might be wea* but "S!P of 8cIo cell in monitor set is good So

we need to ma*e sure there is no pilot pollution in highly call

drop cell area 7or 12 interference, we need to chec* "-P if

"-P is %@d4m greater than normal value E%@(Gd4m 12 interference increase 18 transmit power in connected mode, there over

high 428" cause S"4 reset or "4 reset 12 interference either internal or e9ternal, most of senior 12 interference you will find

due to e9ternal source

So%"t.on: o improve call drop due to S"4 reset we can modify the parameter #o5iscarda95) value 53( <default= to

5H@eaning of this parameter #o/5iscard P51 ma9 X, this parameter is applicable to only ) "2! entity, which is set to

#6B5IS!)"5, means ma9imum number of P51 transmission before "2! entity is rest, if mode is set to #6B5IS!)"5, the "2!

entity will be directly reset if the number of retransmission of P51 reach the value define by parameter -e can set this parameter at

larger value if 428" of transport channel is high o ma*e this parameter value effective ma*e sure parameter )"lc5iscardodeis set to #6B5IS!)"5 mode

'ro!e+"re to mo+.-y t)e /$r$meter :/ command used to change is parameter is /65 1YPS"4"2!: S"4I#58X'%, 26!>I#58X'%, 582)Y!2)SS'%, "!>YP8'"!>B5!>,

6PP6SI8"!>YP8'"!>B5!>, "2!658'), )"2!!7DP)")'85IBS8#58"BP)"),

AMRLCDISCARDMODE=NO2DISCARD, NODISCARDMAXDAT=D30, X-I#56-SI8'5JH, I8""S'50@@,

2)SXP51P622'"18, 2)S"8XP51P622'"18, I8"P622P"6>I4I'#61S85, I8"P622'53@@,

P622P51'#61S85, P622S51'5%, P622-I#56-'5(@, I8"P622P8"I65I!'#61S85,

!7DP622I#DP)")'"18, P622P5176"8#23'5H, P622S5176"8#23'5H

%not)er met)od is Call reesta*lis)ment Met)od to improve call drop:-

!all reestablishment is function by which radio lin*s are reestablished when service interruption or access failure occurs due to

bad "7 environment !all reestablishment can be initiated by 18 or ")# In case of 18, 18 send reestablishment re;uest to

networ* to restore service after detection a downlin* "2 failure or S"4 reset In case of ")#, ")# informs the 18 to start

reestablishment procedure -ith the help of this feature, user e9perience will be rich, because ")4 successes rate will be better

and call drop will get improved here are mainly H reasons for call reestablishment after service get interruption

%/ 52 "adio 2in* failure3/ 12 radio 2in* 7ailure0/ S"4C"4 resetH/ 18 S"4 reset




)s soon as ")# detects the service interruption or access failure, before release of "adio lin*s, call reestablishment get started if

this feature is activated

%/ 52 "adio 2in* 7ailure:/18 continue monitor 52 "2 ;uality, if 18 receives #0%0 #umber

of 61/SY#! indications, 18 start 0%0 timer and if 18 didn+t

receive #0%( number of I#/SY#! indications within timer 0%0So 18 will send !ell 1pdate message with cause value L"adio

2in* 7ailureM to "#! and get inter in the call reestablishment

procedure 6therwise 18 will not send !ell 1pdate message

to "#!Procedure:/#ow 18 will send !ell 1pdate essage with

cause value L"adio 2in* 7ailureM to "#! for call

reestablishment eanwhile 18 will start timer 0%H for !S

service and 0%( for PS service which is ma9imum allowed

time for 18 to try to send !ell 1pdate essage 18 can

resend !ell 1pdate essage to networ* every 0@3 time and

for ma9imum number #0@3 times if 18 didn+t get reply from

the #etwor* If 7aulty "adio 2in*s are restored before 0%H

<for !S=C0%( <for PS= timer gets e9pired, the call

reestablishment is successful, in this case services get

restored or 18 access succeeds If 7aulty "adio 2in*s are not

restored before 0%HC0%( timer get e9pired means service

are released or 18 access fails

3/ 12 "adio 2in* 7ailure:/#ode 4 monitors "2 lin* ;uality and receives

#61SY#!I#5 number of Lout NsyncM indications #ode/4

start the "I7ailure timer if #ode/4 didn+t receive

#I#SY#!I#5 Lin/syncM indication within timer "I7ailure,

#ode/4 stops and reset the timer then "#! activate the

synchroni.ation timer If #ode/4 does not detect 12 "2

Synchroni.ation before Synchroni.ation timer e9pires then

12 "2 call reestablishment triggeredProcedure: / "#! send "adio 2in* )ctivation command to

#ode/4 with Information 8lement LdeactivateM, #ode/4 stop

downlin* power transmission for 18+s "adio 2in* set #ow

"#! start timer for call reestablishment "S?5P)")3 timer

for !S service and "S?5P)")0 timer for PS service If

"#! receives !ell 1pdate essage from 18 before timer

"S?5P)")3C0 get e9pired, then "#! stop the timer and

start call reestablishment and I7 "#! receives !ell 1pdate

message after timer get e9pired then call drop and 18

access failure occurImplementation:/ )fter #ode stop downlin* power

transmission for a 18+s "adio lin*s, 18 will receive #0%0

number of 6ut/sync Indications, 18 will start timer 0%0

and If didn+t receive #0%( number I#/SY#! indication

within the timer get e9pire then 18 will transmit the !ell

1pdate essage with cause ?alue L"adio 2in* 7ailureM to "#! for call

reestablishment eantime 18 start 0%HC0%( timer which is ma9imumallowed time for 18 to send the !ell 1pdate essage to "#! 18 can

resend !ell 1pdate essage to "#! if 18 didn+t get the reply from #etwor*

<"#!= every 0@3 time for a9imum number for #0@3 times If 7aulty

"adio lin*s get restored before timer get e9pired 0%HC0%( then !all

reestablishment is successful otherwise service get released or 18 access

fails0/ S"4 rest: / as we Know in >uawei system, )"2!5IS!)"5658

parameter is set to #6B5IS!)"5, "#! send a signaling message in )< )c* ode= to 18 #ow "#! does not receive

the response from 18 before the number of S"4 "2! P51 retransmission reaches the value of #65IS!)"5)X5)




parameter "#! triggers an S"4 reset and sends the reset P51 message to 18 to reestablish "2! entities on both

sides S"4 reset call reestablishment procedure and implementation is same as 12 "2 failureH/ 18 S"4 "eset:/

"#! does not send "adio 2in* )ctivation command message containing the Information 8lement <I8= LdeactivationM to the

#ode/4 #ow #ode/4 does not stop downlin* power transmission for the 18+s "2 reset Instead, "#! start call

reestablishment after receiving cell update message from 18 Process and implementation is same as 12 "2 failure

Con-.*"r$t.on -or C$%% ree&t$4%.&)ment:

Switch parameters:/

!all reestablishment is controlled by service switch, Process switch and cause switch parameters 7irst we have to enable service

switch before enabling the process switch or cause switch

Parameter #ame >uawei

default

value

"ecommende

d value

"emar*

Service switch "S?54I%B4I3H 5isabled 8nabled Switch that controls call reestablishment for !S service <also for

combine !SOPS service=

"S?54I%B4I3( 5isabled 8nabled Switch that controls call reestablishment for PS service!ause switch "S?54I%B4I33 5isabled 8nabled Switch that controls call reestablishment triggered by S"4 reset

"S?54I%B4I30 5isabled 8nabled Switch that controls call reestablishment tr iggered by "2 failures

imer and counter parameters:/

Parameter name >1)-8I

default ?alue

"ecommende

d value

"emar*

#61SY#!I#5 (@ F imes of successive out/sync indications re;uired for starting the

radio lin* failure timer

#I#SY#!I#5 ( F imes of successive in/sync indications re;uired for the #ode/4

to trigger the radio lin* recovery process

"I7ailure ( sec 0 sec #ode/4 starts the timer after it receives successive out/of/sync

indications of the number defined by #6utsyncInd he #ode/4

shall stop and reset the timer after receiving successive in/syncindications of the number defined by #InsyncInd

rvsdpara%:"S?54I%B4I3

F

% @ Switch that controls Synchroni.ation imer for !S

reestablishment triggered, %:"l"strmr,@:0%0

"I"str mr %%@@@msec %%@@@msec ) timer to "#! wait for radio lin* restoration indication in the

radio lin* procedure

"vsdpara3 @msec %(@@@msec !S imer for 8nhanced !all "eestablishment, start after "#!

send the "2 )ctive !5 , stop after "#! receives cell update

message

"vsdpara0 @msec 0@@@@msec PS imer for 8nhanced !all "eestablishment, , start after "#!

send the "2 )ctive !5 , stop after "#! receives cell update




message

#0%0 (@ 3@ a9imum number of successive out of sync indications

received from 2%

#0%( % % a9imum number of successive in sync indications received

from 2% when 0%0 is activated

0%0 0 sec 0 sec 0%0 is started after the 18 detects consecutive #0%0 out of

syncLindications from 2% 0%0 is stopped after the 18 detectsconsecutive #0%( in sync indications from 2%

0%H @sec %3sec 0%H is started when the criteria for !S radio lin* failure are

fulfilled and only radio bearers associated with 0%H e9ist0%H

is stopped after the !ell 1pdate procedure has been completed

<must be greater than 0@3Q#0@3=

0%( @sec 0@sec 0%( is started when the criteria for PS radio lin* failure are

fulfilled, and only radio bearer associated with 0%( e9ists0%(

is stopped after the !ell 1pdate procedure has been completed

<must be greater than 0@3Q#0@3=

#0@3 0 0 a9imum number of retransmissions of !822 1P5)8C1")

1P5)8

0@3 3@@@msec %H@@msec !822 1P5)8C1") 1P5)8 will be resent upon e9piry of the

timer if ?0@3 less than or e;ual to #0@3

Note:

%/ If !all reestablishment feature already enabled in networ* then don+t change value #61SY#!I#5, #I#SY#!I#5 A

"Ifailure value as I have suggested at Page % A 3 for cell level call drop improvement3/ )fter !all reestablishment feature enabled in the networ* you will see more signaling traffic than before the call

reestablishment feature enabled, reason behind is number of cell update message will get increase for the due to call

reestablishment feature activation

S"**e&t.on: I suggest before implementing call reestablishment feature in the networ*, first we have to ma*e sure that access

failure or !all drop is really happening due to "2 failure or not 7or this purpose need to analysis one or two days !>"C" data

through 6S)" and you will get to *now how many 5rop call or access failure happening due to 12 "adio 2in* 7ailure, if this

value is much then suggest to Implement !all reestablishment feature otherwise #o need




Met)o+ o- $n$%y&.& !$%% +ro/ re$&on 4y OMSTAR:

7or call drop analysis through 6S)" tool we need 0 *inds of data %/ 8ngineering parameter, 3/ !onfiguration data, 0 N!>"C"

data You have to put latest configuration data and !>"C" data, you can ta*e % day or 3 day !>"C" data for call drop analysis

)fter analysis of !>"

logs, you will get result

li*e below:/

Dro/C$%%2D"eTo2ASU2T.meO"t:

7or call drop improvement due to )S1 <)ctive set 1pdate= time out, we can change timer value as per given below/

2 command Parameter name 5efault value "ecommended ?alue "emar*

S8 1S)8I8" >o)sumr (@@@ %@@@@ Improve the !5" due

to 5rop callB5ue

toB)S1Bime6ut

Parameter 1nderstanding: >6)sumr, >6 active set update response timer, ) timer to "#! wait for response to active set update

in soft handover procedure If in your networ* !5" 5ue to B)S1Bime6ut is more than you can increase value of this parameter as

per suggested

Dro/C$%%2D"eTo2U%2R$+.o%.n2F$.%"re:for this case we can implement !all reestablishment feature to Improve drop call rate,

complete study and procedure is given in the previous slides

Dro/C$%%2D"eTo2'5Y2C52RECF67RLCC82T.meO"t,

Dro/C$%%2D"eTo2'5Y2C52RECF6755O82T.meO"t :

o improve the call drop due to Physical channel reconfiguration timer out we can modify the parameter 5o')y!)Re!-*Tmr as per

given below




2 command Parameter name 5efault

value

"ecommended

?alue

"emar*

S8

1S)8I8"

>oPhych"ecfgmr (@@@ %@@@@ Improve the !5" due to

5rop!allB5ueoBP>YB!>B"8!7D<"2!!=Bime6ut

Parameter understanding: >oPhych"ecfgmr, >6 Physical !hannel reconfiguration timer, ) timer to "#! wait for response toPhysical channel reconfiguration in hard handover procedure If you found 5rop!allB5ueoBP>YB!>B"8!7D<"2!!=Bime6ut is

high then you can increase this timer value from (@@@ to %@@@@ and monitor the result if result is Ove then *eep the value same

otherwise revert it bac*

$ropCall#$ueo#!(#!+C",$CCC#imeOut/

$ropCall#$ueo#!(recfgPeriodic $!$#imeOut/ $ropCall#$ueo#!(!+L


S8 1S)8I8" "bSetup"spmr (@@@ %@@@@ Improve the !5"

5ueoB"4setupBime6ut

S8 1S)8I8" "b"ecfg"spmr (@@@ %@@@@ Improve the !5"

5ueoB"4recfgBime6ut

S8 1S)8I8" "b"el"spmr (@@@ %@@@@ Improve the !5"

5ueoB"4"82Bime6ut

Parameter understanding: %/ "bSetup"spmr, -ait "4 setup response timer, this is ) timer to "#! wait for the "4

setup response from 18 in the "4 procedure, 3/ "b"ecfg"spmr, -ait "4 reconfiguration response timer, this is ) timer used to

wait for the "4 reconfiguration response from 18 in the "4 procedure, 0/ "b"el"spmr, -ait "4 release response timer, this is )

timer to "#! wait for the "4 release response from 18 in the "4 procedure If you found call drop due to these 0 reasons in your

networ* you can change parameter value from (@@@ to %@@@@, hopefully call drop will get improve

$ropCall#$ueto#MeasCtrl#No#!eply : drop call due to measurement controlB#oBreply is under the case of poor

coverage 18 sends measurement to "#! but didn+t get reply from the "#! his case I have already discussed in the previous

slides, we can change the a9 "2 52 power to improve the drop call

Some ot)er /$r$meter or &w.t!)9& to .m/ro#e t)e +ro/ !$%% r$te

C-*Sw.t!):

!hannel !onfiguration Strategy Switch, CF62DL2LIND2DETECTION2S(ITC5,when the switch is on, the 52 blind transport

format detection function is used for single S"4 and )"OS"4 bearers #ote that the 18 is only re;uired to support the blind

transport format stipulated 4ut you may find some 18 which will not support 52 42I#5 detection 4ut still we can ma*e switch

enable to improve the drop call

2 command Parameter name 5efault

value

"ecommend

ed ?alue

"emar*

S8

1!6"")2D6S-I!>

!7DB52B42I#5B588!I6

#BS-I!>

6# Some 18 may not support 52 blind

detection

o improve these 0 counter we can modify the "4 setup

and reconfiguration timers, as per detail given below




Some /$r$meter -or 'S !$%% +ro/:

#eed to chec* below PS inactive timers and optimi.e as per the suggested value


S8 1PSI#)!I8" PSI#)!"76"!6

#

3@ %(

S8 1PSI#)!I8" PSI#)!"76"S" 3@ %(

S8 1PSI#)!I8" PSI#)!"76"I# 3@ %(

S8 1PSI#)!I8" PSI#)!"76"4)! 3@ %(

Parameter 1nderstanding:/

%/ PsInactmr7or!on:/ -hen detecting that the PsR !onversational 1ser had no data to transfer for a long time which longer

than this timer, the P5!P layer would re;uest the ""! layer to release this ")4 If this parameter value set to very small

value then "#! will release the 18 ")4 that stop processing service this will saves networ* resources 4ut this will lead

to fre;uent ")4 release and ")4 assignment re;uest, it will result as number of signaling message increase, !P1

loading increase If parameter value set to larger value, "#! will hold "adio 2in*s for that 18 till timer get e9pire his will

lead to waste networ* resources3/ PsInactmr7orStr :) -hen detecting that the PsR Streaming 1ser had no data to transfer for a long time which longer than

this timer, the P5!P layer would re;uest the ""! layer to release this "adio )ccess 4ear If this parameter value set tovery small value then "#! will release the 18 ")4 that stop processing service this will saves networ* resources 4ut

this will lead to fre;uent ")4 release and ")4 assignment re;uest, it will result as number of signaling message

increase, !P1 loading increase If parameter value set to larger value, "#! will hold "adio 2in*s for that 18 till timer get

e9pire his will lead to waste networ* resources0/ PsInactmr7orInt:/ -hen detecting that the PsR Interactive 1ser had no data to transfer for a long time which longer than

this timer, the P5!P layer would re;uest the ""! layer to release this "adio )ccess 4ear If this parameter value set to

very small value then "#! will release the 18 ")4 that stop processing service this will saves networ* resources 4ut



e9pire his will lead to waste networ* resourcesH/ PsInactmr7or4ac:/ -hen detecting that the PsR 4ac*ground 1ser had no data to transfer for a long time which longer

than this timer, the P5!P layer would re;uest the ""! layer to release this "adio )ccess 4ear If this parameter value set

to very small value then "#! will release the 18 ")4 that stop processing service this will saves networ* resources 4ut



e9pire his will lead to waste networ* resources

Suggestion:/ I have tried to describe the all the case which I faced during my project wor* I hope this document will help

you to solve the drop call issue I suggest , before change the parameter , ma*e proper !hange re;uest and ta*e

approval from echnical director , supervisor , customer etc also ma*e sure parameter change doesn+t no impact at live

networ* if have impact at live networ* then change only in night time during wee hours only

http://localhost:7890/pages/GEC0815J/02/GEC0815J/02/resources/EN/UMTS/BSC6910/MML/mbsc/m-para/upsinacttimer_psinacttmrforcon.html


http://localhost:7890/pages/GEC0815J/02/GEC0815J/02/resources/EN/UMTS/BSC6910/MML/mbsc/m-para/upsinacttimer_psinacttmrforstr.html

http://localhost:7890/pages/GEC0815J/02/GEC0815J/02/resources/EN/UMTS/BSC6910/MML/mbsc/m-para/upsinacttimer_psinacttmrforint.html

http://localhost:7890/pages/GEC0815J/02/GEC0815J/02/resources/EN/UMTS/BSC6910/MML/mbsc/m-para/upsinacttimer_psinacttmrforbac.html


http://localhost:7890/pages/GEC0815J/02/GEC0815J/02/resources/EN/UMTS/BSC6910/MML/mbsc/m-para/upsinacttimer_psinacttmrforstr.html

http://localhost:7890/pages/GEC0815J/02/GEC0815J/02/resources/EN/UMTS/BSC6910/MML/mbsc/m-para/upsinacttimer_psinacttmrforint.html



Call Drop Improvement Case Study (1)

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