3 WCDMA a en UMTS Handover Optimization 1 WORD 201005 59

8/17/2019 3 WCDMA a en UMTS Handover Optimization 1 WORD 201005 59

1/57

UMTS Handover Optimization

Version 1.00

ZTE CORPORATIONZTE Plaza, Keji Road South,Hi-Tech Industrial Par,Nanshan !istrict, Shenzhen,P" R" China#$%' Tel( )%*+ '## *''$&& %&&-%.&-%.&/a0( )%*+ '## *''.*1R2( htt3(44su33ort"zte"co5"cnE-5ail( doc6zte"co5"cn

http://support.zte.com.cn/http://support.zte.com.cn/mailto:[email protected]:[email protected]://support.zte.com.cn/


2/57

Contents

Chapter 1.................................................................1

Handover Performance Analysis and Optimization.......1

DT Optimization Analysis...................................................2

Causes for Intra-Frequency Handover Failures...........................2

Corner ffect......................................................................!2

Causes for Inter-Frequency Handover Failures.........................!"

Causes for Inter-#AT Handover Failures..................................!$

Optimization of t%e Traffic &tatistics..................................!$

Causes for &oft Handover Failure...........................................!'

Causes for Inter-Frequency Handover Failure...........................22

Analysis of t%e #eason for t%e Out(oin( C& Inter-#AT HandoverFailure............................................................................... 2)

Analysis of t%e #eason for t%e Out(oin( *& Inter-#AT Handover

Failure............................................................................... 2'

Chapter 2................................................................33

Cases of Handover Performance Optimization............33

Cases of Intra-#AT Handover Optimization.........................++

Handover Failure and Call Drop Caused ,y Corner ffect...........++

Handover Failure and Call Drop Caused ,y *inpoint ffect..........+"

Handover Failure and Call Drop Caused ,y Insufficient *&C #euse

Distance.............................................................................

Handover Failure and Call Drop Caused ,y /imited &ystem#esources.......................................................................... )

Inter-#AT Handover Cases..............................................."

Handover Failure Caused ,y Improper Intra-#AT Handover*arameter Confi(uration......................................................."

Handover Failure Caused ,y 0ron( Confi(uration of Intra-#AT1ei(%,orin( cells.................................................................)

Inter-#AT *& Domain Handover Failure Caused ,y 1o #outin(et3een &4&1s..................................................................)+


3/57

C h a p t e r 1

Handover Performance

Analysis and Optimization

Confidential and *roprietary Information of 5T CO#*O#ATIO1 1


4/57

67T& Handover Optimization

DT Optimization Analysis

Causes for Intra-Frequency

Hano!er Failures

F I U ! " 1 A #A$%SIS F $ O & F O ! I #T !A 'F !" ( U" #C% HA#)O * " ! F AI $ U!" S

2 Confidential and *roprietary Information of 5T CO#*O#ATIO1


5/57

C%apter ! Handover *erformance Analysis and Optimization

"issin# $ei#%&orin# cells

8ud(ment of missin( nei(%,orin( cells

1ei(%,orin( cells refer to cells t%at may enter t%e active set9 andcells t%at t%e 6 may reselect as t%e servin( cell or may ,e%anded over to. 0%en t%e 6 is at idle or FACH state9 it can readt%e nei(%,orin( cell information from t%e system information9and it 3ill measure t%ese cells 3%en t%e conditions are fulfilled.T%erefore9 missin( nei(%,orin( cells may cause t%at t%e cellreselection cannot ,e finis%ed in time9 3%ic% furt%er leads to call

setup failure. 0%en t%e 6 is at DCH state9 t%e #1C 3ill delivert%e nei(%,orin( cell information to t%e 6 t%rou(% t%e

measurement control command9 and instruct t%e 6 to measureall t%e nei(%,orin( cells t%at it may ,e %anded over to. In t%is

condition9 missin( nei(%,orin( cells may lead to call drops.

4enerally9 t%e follo3in( t%ree met%ods can ,e used to :ud(emissin( nei(%,orin( cells;

!. est &C of t%e 6 and est &C of t%e &canner

7issin( nei(%,orin( cells may lead to call drops. If ,ot% t%e6 and t%e &canner are used in t%e test9 3e can c%ec<3%et%er t%ere are any missin( nei(%,orin( cells ,ycomparin( t%e c=Io of t%e optimal servin( cell in t%e active

set of t%e 6 and t%e c=Io of t%e optimal servin( cellsmeasured ,y t%e &canner. If t%e c=Io of t%e optimal servin(

cell 3it%in t%e active set of t%e 6 is poor9 3%ile t%atmeasured ,y t%e &canner is (ood9 and t%e *&Cs of t%e

optimal servin( cell recorded ,y t%e &canner is not includedin t%e Measurement Control si(nalin( delivered ,y t%e#1C9 it is certain t%at t%e some nei(%,orin( cells aremissin(.

As s%o3n in t%e fi(ure ,elo39 on one road9 t%e Best C !y"c#$o measured ,y t%e 6 is poor9 lo3er t%an -!!d9 3%ilet%at recorded ,y t%e &canner is (ood9 %i(%er t%an -$ d. T%eoptimal servin( cell recorded ,y t%e &canner is !' and '93%ile t%at of t%e 6 is !>. T%rou(% t%e MeasurementControl si(nalin( received ,y t%e 69 3e find out t%at Cell!' and cell ' are not included in t%e nei(%,orin( cell list.From t%is9 it is safe to ascertain t%at some nei(%,orin( cells

are missin(.



6/57


F I U ! " + , U) I # M I S S I # #" I H-O !I # C" $ $ S - % - "S T SC O F T H" U"A# ) T H" SCA##" ! .1 /

F I U ! " 0 ,U) I # M I S S I # #" I H-O !I # C" $ $ S - % -" ST SC O F T H" U"A# ) T H" SCA##" ! .+ /

2. *ilot set of t%e 6

If only t%e 6 is used in t%e test9 3e can :ud(e 3%et%ert%ere are missin( nei(%,orin( cells ,y c%ec


7/57


2. T%e *&C of t%e cell t%at t%e 6 accesses after t%e call dropis different from t%e one t%at t%e 6 accessed ,efore t%e calldrop@ +. T%ere is no record a,out t%is cell in t%e lastMeasurement Control messa(e t%at t%e 6 received ,efore

t%e call drop.As s%o3n in t%e fi(ure ,elo39 Cell22" 3it% stron( pilotstren(t% is included in t%e detective set. After t%e call drop9t%e 6 accesses Cell22". Ho3ever9 Cell22" is e?cluded in t%enei(%,orin( cell list delivered ,y t%e last MeasurementControl messa(e. T%en9 3e can ascertain t%at Cell22" is t%emissin( nei(%,orin( cell.

F I U ! " P I $ O T S " T O F T H" U" -" F O !" T H " CA$ $ )!O P

F I U ! " 2 P I $ O T S " T O F T H" U" AF T " ! T H" CA$ $ )!O P

+. C1A pilot pollution analysis al(orit%m 2

C1A pilot pollution analysis al(orit%m 2 is used to c%ec< t%e

test data of t%e 6. *ilot pollution refers to t%e condition t%att%e pilots t%at e?ceed t%e pilot pollution t%res%old are not

included in t%e active set after certain la( time. 0%en t%e 6is used in t%e test9 t%e condition t%at t%e missin( nei(%,orin(cells t%at cannot :oin t%e active set in a s%ort period of timedeteriorates t%e c=Io of t%e servin( cell and (enerates e?trainterference. T%e pilot pollution analysis al(orit%m 2 can



8/57


speedily locate t%e potential area 3it% missin( nei(%,orin(cells. T%en9 t%e pilot set of t%e 6 can ,e used to c%ec<3%et%er t%e pro,lem e?ists.

As s%o3n in t%e fi(ure ,elo39 you can locate t%e pilot

pollution area ,y pilot pollution analysis al(orit%m 29 andt%en use t%e 6 to :ud(e 3%et%er t%e pilot pollution iscaused ,y missin( nei(%,orin( cells. From t%e pilot set of t%e69 3e can :ud(e t%at Cell!' is t%e missin( nei(%,orin(cell.

F I U ! " 3 US I # P I $ O T P O $ $ UT I O # A#A$%SIS A$ O !I T HM + T O CH" C4 F O ! M I S S I # #" I H-O !I # C" $ $ S

&olution for missin( nei(%,orin( cells

Once t%e missin( nei(%,orin( cells are detected9 you s%ould addt%e cells to t%e nei(%,orin( cell list in t%e O7C-#. 1ote t%atmore confi(ured nei(%,orin( cells does not necessarily represent

t%e net3or< performance is ,etter. It is t%e quality of t%enei(%,orin( cells t%at impacts t%e net3or< performance. If too

many nei(%,orin( cells are confi(ured9 t%e nei(%,orin( cell

searc%in( period 3ill ,e prolon(ed9 and t%en t%e equipmentperformance 3ill ,e impacted@ on t%e contrary9 if somenei(%,orin( cells are missin(9 unnecessary interference 3ille?ist9 and call drop may occur. At t%e initial sta(e of net3or<construction9 t%e net3or< en(ineers set t%e nei(%,orin( cellrelation ,ased on field inspection and distri,ution of t%e ,asestations. After t%e net3or< is put into commercial operation9 t%e

net3or< load is added 3it% t%e increase of su,scri,ers. In t%iscondition9 t%e en(ineer can optimize t%e nei(%,orin( cell

confi(uration ,y tracin( t%e detected set and 7#.



9/57


'ilot 'ollution

8ud(ment of pilot pollution

*ilot pollution is t%e most common pro,lem in 67T&. In plainterms9 it refers to t%e condition t%at t%e pilot si(nals receivedfrom different cells are similar eit%er stron( or 3ea


10/57


%ave e?ceeded t%e pilot pollution t%res%old9 and t%e num,er of t%e active set is set to +9 so t%e num,er of pilot pollution is . If t%e #&C* T%res%old is set to ,e lar(er t%an -!) dm9 and t%ec=Io T%res%old is set to ,e lar(er t%an -!$ d9 t%en four pilots

%ave e?ceeded t%e pilot pollution t%res%old. ecause t%e activeset is set to +9 t%e num,er of pilot pollution is !.

F I U ! " 6 " 7 AM P $ " O F P I $ O T P O $ $ UT I O # A#A$ % S I S A$ O !I T HM O # "

Al(orit%m t3o does not consider t%e num,er of pilots in t%e

active set9 and it is applica,le to t%e test data of t%e 6. *ilotpollution refers to t%e condition t%at t%e pilots t%at e?ceed t%epilot pollution t%res%old are not included in t%e active set aftercertain la( time. In al(orit%m t3o9 pilot pollution is defined asfollo3s; #&C* -') dm #&C* T%res%oldB9 and c=Io !+ dc=Io T%res%oldB. 1um,er of t%e pilot pollutions refers to t%e

pilots t%at %ave e?ceeded t%e pilot pollution t%res%old9 and arenot included in t%e active set after certain la( time.

0%en t%e parameters related to pilot pollution is set as s%o3n int%e fi(ure ,elo39 t%ree pilots %ave e?ceeded t%e pilot pollutiont%res%old. After ! s9 pilot 222 and pilot !2+ still are not includedin t%e active set9 so t%e num,er of pilot pollution is 2.

F I U ! " 8 " 7 AM P $ " O F P I $ O T P O $ $ UT I O # A#A$ % S I S A$ O !I T HM T &O

Al(orit%m t%ree9 defined ,y C%ina 6nicom9 is applica,le to t%etest data of t%e &canner and t%e 6. Here9 pilot pollution refers

to t%e num,er of pilots t%at %as e?ceeded t%e pilot pollution



11/57


t%res%old and t%e active set t%res%old. In al(orit%m t%ree9 pilotpollution is defined as follo3s; #&C* -! dm #&C*T%res%oldB9 and c=Io !est&ervin(Cell - )d c=IoT%res%oldB. 0e can (et t%e num,er of pilot pollutions ,y

su,tractin( + active setB from t%e total num,er of pilots t%at%as e?ceeded t%e pilot pollution t%res%old.

As s%o3n in t%e fi(ure ,elo39 3%en t%e parameters related topilot pollution is set as s%o3n in Fi(ure " 9 si? pilots %avee?ceeded t%e pilot pollution t%res%old. ecause t%e active set isset to +9 t%e num,er of pilot pollution is +.

F I U ! " 19 "7 AM P $ " O F P I $ O T P O $ $ UT I O # A#A$ % S I S A$ O !I T HM T H!" "

&ote'

T%e parameter settin(s of t%e t%ree al(orit%ms are different9so t%eir conclusions also may differ. *ilot pollution analysiscan %elp to locate t%e area 3it% possi,le pilot pollution

pro,lems. T%erefore t%ese t%ree al(orit%ms 3it% differentparameter settin(s can ,e used to analyze t%e condition of

t%e net3or< from different aspects. T%en9 3e can putfor3ard a more customized net3or< optimization solution.

For C%ina 6nicom pro:ects9 it is recommended to useal(orit%m t%ree to evaluate t%e pilot pollution level.

T%e follo3in( fi(ure s%o3s t%e analysis c%art of pilot pollution

al(orit%m t%ree. 9 !9 29 and + represent t%e num,er of pilotpollution.



12/57


F I U ! " 11 A#A$%SIS C H A ! T O F P I $ O T P O $ $ UT I O # A$ O !I T HM T H!" "

&olution for pilot pollution

To solve t%e pilot pollution pro,lem9 3e %ave to find one maincovera(e pilot 3it%in t%e pilot pollution area9 3%ic% can ,e

performed ,y t%e follo3in( steps;

!. Add ,ase stations.

If pilot pollution %appens in areas 3it% stron( covera(esi(nals9 reconstruct t%e am,ient ,ase stations to omni cellsor 2-sector ,ase stations to reduce t%e num,er of pilots@ if pilot pollution %appens in areas 3it% poor covera(e si(nals9add a ne3 ,ase station in t%e polluted area. It is common toadd ,ase stations in t%e pilot polluted areas. T%e 3or


13/57


14/57


%as little impact on system covera(e. It is recommended touse t%e plannin( soft3are 3it% advanced al(orit%ms and %i(%accuracy to do t%e simulation. Durin( t%e DT9 severalen(ineers can 3or< to(et%er to modify t%e parameters.

. #eplace t%e ori(inal antenna 3it% #emote lectrical Tilt#TB.

0%en t%e do3ntilt of mec%anical antennas is increased9 t%e

antenna ,eam 3ill ,e flattened9 and more si(nals cover t%eside lo,e. T%en covera(e of t%e side lo,e to ot%er cells 3ill

increase9 and t%e ne3 pilot pollution may occur. For t%e #T9t%is


15/57


F I U ! " 1+ C O !#" ! " F F " CT A#) S I #A$ CHA# " S

&olution;

From t%e a,ove analysis9 3e can see t%at corner effect is mainly

caused ,y a,rupt drop of t%e c=Io in t%e source cell andincrease of c=Io in t%e tar(et cell. To counter t%e corner effect9

you s%ould include t%e tar(et cell into t%e active set ,efore t%esi(nal of t%e source cell drops a,ruptly. T%e follo3in( met%ods

can ,e used to counter t%e corner effect.

!. Ad:ust cell CIO.

&et t%e CIO of t%e tar(et cell to a positive value9 so t%etar(et cell can report vent !A as soon as possi,le9 and t%enit can enter t%e active set ,efore t%e si(nal of t%e source celldrops a,ruptly. T%is settin( also ma


16/57


2. Ad:ust cell #!a #pt#an(eB9 H!a HysteresisB9 and Time toTri((er.

y increasin( #!a9 decreasin( H!a and Time to Tri((er of t%e

source cell9 its nei(%,orin( cells can report vent !A early9

and t%e tar(et cell also can enter t%e active set early.

Compared 3it% ad:ustin( t%e cell CIO9 ad:ustin( #!a9 H!a9and Time to Tri((er may influence t%e %andover ,et3een t%e

source cell and t%e nei(%,orin( cells.

+. Ad:ust t%e #F parameters.

y ad:ustin( t%e #F parameters9 t%e antenna of t%e tar(etcell can cover across t%e corner9 so t%e %andover %appens,efore t%e 6 reac%es t%e corner. Or9 you can ma


17/57


F I U ! " 10 P I #P O I #T " F F " CT A# ) S I #A$ CHA# " S

&olution;

From t%e a,ove analysis9 3e can see t%e pinpoint effect ismainly caused ,y a,rupt drop and t%e su,sequent arise of c=Ioin t%e source cell in a s%ort period of time.

ecause t%e si(nal quality in t%e source cell only drops in as%ort period of time9 to counter t%e corner effect9 you s%ouldensure t%at t%e source cell remains in t%e active set 3%en itssi(nals drop a,ruptly. T%e follo3in( met%ods can ,e used tocounter t%e pinpoint effect.

!. Ad:ust cell CIO.

&et t%e CIO of t%e tar(et cell to a positive value9 3%ic%ma


18/57


t%en it can remain in t%e active set 3%en its si(nals dropa,ruptly.

2. Ad:ust cell #!a #pt#an(eB9 H!a HysteresisB9 and Time to

Tri((er.

y increasin( #!a and Time to Tri((er and decreasin( H!a of

t%e tar(et cell9 you can ma


19/57


cenarios Causes

T%e 6 receives t%e Active et+pdate messa(e9 ,ut does notrespond.

T%e 6 is faulty.

T%e 6 sends t%e Active et+pdate Complete#-ailuremessa(e9 ,ut t%e #1C fails toreceive it.

T%e 6/ is faulty9 or t%e timer foractive set update e?pires9 and t%e

connection is released.

T%e %andover-tar(et 1ode

does not send t%e (adio )in*(estore $ndication messa(e

to t%e #1C.

T%e 6/ of t%e tar(et 1ode is notsync%ronized 3it% t%e 6.

Causes for Inter-Frequency

Hano!er Failures

Inter-frequency %andover mainly %appens amon( t%e inter-frequency nei(%,orin( cells. T%e place and condition of inter-frequency %andovers must ,e properly set. 4enerally9 if t%e

t%res%old for ena,lin( t%e compressed mode of t%e inter-frequency %andover is too %i(%9 t%e 6s frequently ena,les t%e

compressed modes 3%en t%ey are near t%e cell ed(e9 and t%enmuc% si(nalin( over%ead are 3asted9 and system interference is

(enerated. If t%e t%res%old is too lo39 t%e compressed mode

measurement is tri((ered too late and t%e %andover cannot ,eperformed timely. T%en9 call drops 3ill occur.

T%e main cause for t%e inter-frequency %andover failure is t%at

t%e %andover area is too narro39 so t%e 6 reac%es t%e cell ed(e :ust after it started t%e inter-frequency measurement. T%e

%andover measurement cannot ,e finis%ed.

Durin( t%e indoor=outdoor %andover9 if t%e indoor and

outdoor cells are at different frequencies9 t%e %andover successrate 3ill ,e lo3er t%an t%e soft %andover success rate. To solve

t%is pro,lem9 you can use t%e follo3in( met%ods;

!. Ad:ust t%e %andover parameters to control t%e indoor and

outdoor %andover area.

2. &et t%e %andover areas at places 3it% little traffic.

+. Construct a transitional cell in indoor area9 so t%e inter-frequency %andover can %appen indoors.

. Install t%e antenna in a proper location and control t%e po3erat t%e antenna port to ad:ust t%e area of %ard %andover.



20/57


Causes for Inter-AT Hano!er

Failures

T%e (eneral causes for inter-#AT %andover failures are asfollo3s;

!. T%e quality of 6/ is poor.

2. T%e t%res%old for vent 2D is set improperly.

+. T%e parameter for vent +A is set improperly.

. &ome 4&7 nei(%,orin( cells of t%e current 67T& cell aremissin(.

). Too many 4&7 nei(%,orin( cells are confi(ured for t%e 67T&

cell.

>. 1o radio resources are availa,le for t%e tar(et 4&7 cell.

T%e optimization of t%e %andover ,et3een 67T& and 4&7 is tooptimize t%e ,oundaries of t%e 67T& and 4&7 net3or


21/57


F I U ! " 1 H A#)O * " ! T !AF F I C STATISTIC A#A$ % S I S F $ O &

Causes for ,oft Hano!er Failure

T%e soft %andover failure can ,e analyzed from t%e follo3in(aspects; association data9 fore(round and ,ac


22/57


F I U ! " 12 SO F T HA#)O * " ! F AI $ U!" A#A$%SIS F $ O &

T%e %andover procedure contains t%ree sta(es; %andoverdecision sta(e9 %andover preparation sta(e9 and %andover on

t%e 6u interface.

Handover decision sta(e

T%e 6 reports vent !A9 !9 and !C9 and t%en t%e #1Cadmission control module determines 3%et%er to let t%e 6 to

,e %anded over to t%e tar(et cell ,ased on t%e current systemresources of t%e tar(et cell. If t%e tar(et cell can providesufficient resources9 t%e #1C tri((ers t%e %andover preparation.T%e #1C sends t%e (adio )in* etup (e,uest messa(e torequest t%e 1ode to ,uild t%e correspondin( #/@ if t%e tar(etcell cannot provide sufficient resources9 t%e #1C tri((ers t%e

con(estion control flo39 and postpones t%e %andlin( of t%eevents. ou can c%ec< 3%et%er t%e %andover failure is caused ,y

t%e con(ested tar(et cell ,y t%e %andover con(estion rate.

Handover preparation sta(e



23/57


T%e #1C receives t%e measurement report sent ,y t%e 69 andt%en instructs t%e tar(et 1ode to ,uild t%e correspondin( #/st%rou(% t%e (adio )in* etup (e,uest messa(e. After t%e #/sare successfully ,uilt9 t%e %andover on t%e 6u interface ,e(ins.

If t%e 1ode returns t%e (adio )in* etup -ailed messa(e9t%e %andover preparation fails. T%e causes t%at may lead to%andover preparation failure are included in t%e follo3in( ta,le.

TA-$ " + CAUS " S F O ! !$ A))I T I O # :S" T UP F AI $ U!" O # T H" I U- I#T " !F AC"

Causes for () Addition#etup -ailure on the $u! $nterface

T1A*ulsfnotsupported

T1A*dlsFnotsupported

T1A*cmnotsupported

T1A*transportresourceunavaila,le

T1A*requestedconfi(urationnotsupported

T1A*unspecified2

1o response

Handover on t%e 6u interface sta(e

After t%e tar(et 1ode finis%es ,uildin( t%e #/s9 t%e #1C

instructs t%e 6 to perform t%e %andover t%rou(% t%e Activeet +pdate si(nalin(. After t%e %andover is completed9 t%e 6

reports t%e Active et +pdate Complete messa(e. If t%e 6returns Active et +pdate -ailed or t%e #1C receives no

response from t%e 69 t%en t%e %andover on t%e 6u interfacealso fails. T%e causes t%at may lead to %andover failure on t%e6u interface are included in t%e follo3in( ta,le.

TA-$ " 0 " #" !A$ C AUS " S F O ! ACT I * " S" T UP)AT" F AI $ U!"

eneral Causes for Active et +pdate -ailure

Confi(uration unsupported

*%ysical c%annel failure

Incompati,le simultaneous reconfi(uration

Compressed mode runtime error

*rotocol error

Cell update occurred

1o response

Current t%e soft %andover success rate only refers to t%e%andover success rate on t%e 6u interface.



24/57


Causes for Inter-Frequency

Hano!er Failure

F I U ! " 13 I #T " ! ' F !" ( U" #C% HA#)O * " ! F AI $ U!" A#A$%SIS F $ O &

T%e inter-frequency %andover procedure contains t%ree sta(es;



25/57


%andover decision sta(e9 %andover preparation sta(e9 and%andover on t%e 6u interface.

T%e %andover decision sta(e is mainly to :ud(e 3%et%er t%e

inter-frequency cells can provide sufficient resources to ,uild t%e

ne3 services.

T%e inter-frequency %andover preparation sta(e is similar to t%atof t%e soft %andover.

For t%e %andover on t%e 6u interface9 t%e #1C adopts t%e (adioBearer (econfi/urationJ %ransport Channel(econfi/urationJ Physical Channel (econfi/urationmessa(es to instruct t%e 6 to perform t%e %ard %andover9 and

t%en t%e 6 reports t%e (adio Bearer (econfi/urationcompleteJ %ransport Channel (econfi/uration completeJ

Physical Channel (econfi/uration Complete messa(e aftert%e %ard %andover is completed. If t%e 6 returns (adio Bearer

(econfi/uration -ailedJ %ransport Channel (econfi/uration-ailedJ Physical Channel (econfi/uration -ailed or t%e #1Creceives no response from t%e 69 t%en t%e %andover on t%e 6uinterface also fails. T%e causes t%at may lead to %andover failureon t%e 6u interface are included in t%e follo3in( ta,le.

TA-$ " !" AS O #S F O ! UU I#T " !F AC" HA#)O * " ! FAI $ U!"

-ailure Course (eason for Active et +pdate -ailure

Confi(uration

unsupported

If t%e %ard %andover of t%e 6 to t%e tar(et cellis decided to ,e made9 t%e #1C 3ill send t%ereconfi(uration messa(e to t%e 6. T%e

reconfi(uration messa(e includes multiple


26/57


-ailure Course (eason for Active et +pdate -ailure

Incompati,le

simultaneousreconfi(uration

If t%e %ard %andover of t%e 6 to t%e tar(et cellis decided to ,e made9 t%e #1C 3ill send t%ereconfi(uration messa(e to t%e 6. If t%e 6 is

,usy 3it% dealin( t%e ot%er messa(es 3%enreceivin( t%is messa(e9 t%e 6 3ill send t%ereconfi(uration failure messa(e to t%e #1C9 andt%e reason is incompati!le simultaneousreconfi/uration.

Compressedmode runtimeerror

If t%e %ard %andover of t%e 6 to t%e tar(et cellis decided to ,e made9 t%e #1C 3ill send t%ereconfi(uration messa(e to t%e 6. If t%ereconfi(uration messa(e carries t%e compressedmode parameter9 and t%e multi activatedtransmission (ap pattern sequences create t%etransmission (aps in t%e same radio frame9 t%e6 3ill send t%e reconfi(uration failure messa(e

to t%e #1C9 and t%e reason is t%e compressionmode runtime error. One radio frame can onlyinclude t%e transmission (ap of one function.T%e transmission (ap is t%e time slot used fort%e inter-frequency=inter-#AT measurement inone radio frame.

*rotocol error

If t%e %ard %andover of t%e 6 to t%e tar(et cellis decided to ,e made9 t%e #1C 3ill send t%e

reconfi(uration messa(e to t%e 6. If someparameters in t%e reconfi(uration messa(e do

not conform to t%e protocol suc% as (rammarmista


27/57


Analysis of t%e eason for t%e

Out#oin# C, Inter-AT Hano!er

Failure

Out(oin( C& inter-#AT %andover includes t%e follo3in( t3op%ases; t%e out(oin( C& inter-#AT %andover preparation at t%elu interface and t%e out(oin( inter-#AT %andover request on t%e6u interface. T%e out(oin( C& inter-#AT %andover preparation att%e lu interface corresponds to t%e messa(e of relocation

preparation9 and t%e out(oin( inter-#AT %andover requirementon t%e 6u interface corresponds to t%e HA1DOK# -(OM

+%(A& COMMA&0 messa(e.

T%e out(oin( C& inter-#AT %andover preparation is t%erelocation process ,et3een t%e #1C and t%e &C. After t%e #1Creceives vent +A=+C reported ,y t%e 69 t%e #1C :ud(es

3%et%er t%e %andover from +4 to 24 is possi,le. If it is9 t%e #1C3ill send t%e (elocation (e,uired messa(e to t%e C1. T%en9

t%e C1 3ill send t%e %andover request to t%e &C. If t%e%andover is allo3ed9 t%e &C 3ill allocate t%e necessaryresources and returns t%e confirmin( messa(e to t%e C1. T%eC1 sends t%e #A1A* messa(e (elocation Command to t%eC9 and t%e %andover preparation is finis%ed. T%e relevantcounters in t%e out(oin( C& inter-#AT %andover preparationprocess are descri,ed in t%e follo3in( ta,le.

TA-$ " 2 !" $ " * A#T CO U#T " !S I # T H" O UT O I # CS I#T " ! '!AT H A#)O * " !P!"PA!ATIO# P!O C" S S

Counter 0escription

1um,er ofattemptedrelocation

preparation forout(oin( C&inter-#AT

%andovers9 time

critical relocation

T%e measurement o,:ect of t%e counter is t%ecell. T%e counter is used to count t%e num,er oft%e inter-#AT C& domain %andover out(oin(preparation requests and t%e request cause is %ime Critical (elocation. Time criticalindicates all emer(ent cases suc% as9transmission resources are ,loc


28/57


Counter 0escription

attemptedrelocation


%andovers9

relocationdesira,le for

radio reasons

cell. T%e counter is used to count t%e num,er oft%e inter-#AT C& domain %andover out(oin(

preparation requests and t%e request cause is

(elocation 0esira!le for (adio (easons. T%e6 is %anded over into different system ,ecauset%e quality of t%e radio lin< is not (ood at t%e

#1C side ,ut (ood in anot%er system.

At t%is time t%e reason of t%e accompaniedrelocation is t%e radio quality.


preparation forout(oin( C&

inter-#AT

%andovers9directed retry

T%e measurement o,:ect of t%e counter is t%ecell. T%e counter is used to count t%e num,er oft%e inter-#AT C& domain %andover out(oin(preparation requests and t%e request cause is0irected (etry.

T%e inter-#AT %andover occurs ,ecause t%e voice

service esta,lis%ment fails due to t%e resourcecon(estion at t%e C side.

1um,er of

attemptedrelocation


%andovers9reduce load inservin( cell

T%e measurement o,:ect of t%e counter is t%ecell. T%e counter

is used to count t%e num,er of t%e inter-#AT C&domain %andover out(oin( preparation requests

and t%e request cause is (educe )oad inervin/ Cell. T%e inter-#AT %andover occurs

,ecause t%e load at t%e C side is too %i(%.



%andovers9access restricted

due to s%ared

net3or


29/57


Counter 0escription

e?piry

to set t%e relocation preparation timer afterreceivin( t%e (")OCA%$O& COMMA&0 messa(e from t%e C19 t%e #1C stops t%e

relocation preparation timer. If t%e #1C fails toreceive t%e response from t%e C1 after t%erelocation preparation timer timeout9 t%e Ccancels t%e relocation flo3.

1um,er of failedrelocation

preparation for

out(oin( C&inter-#AT

%andovers9relocation failure

in tar(et C1=#1Cor tar(et system

T%e measurement o,:ect of t%e counter is t%ecell. T%e counter is used to count t%e num,er oft%e inter-#AT C& domain %andover out(oin(preparation failures and t%e failure cause is(elocation -ailure $n %ar/et C(&C Or%ar/et ystem.

After t%e C sends t%e (")OCA%$O&("+$("0 messa(e to t%e C1 and if t%erelocation fails due to t%e operation error at t%eC1 or 24 side9 t%e C1 sends t%e (")OCA%$O&P("PA(A%$O& -A$)+(" messa(e 3it% t%iscause value.



%andovers9

relocation notsupported in

tar(et

#1C or tar(et

system


is used to count t%e num,er of t%e inter-#AT C&domain %andover out(oin( preparation failuresand t%e failure cause is (elocation &otupported $n %ar/et (&C Or %ar/et ystem.

After t%e C sends t%e (")OCA%$O&("+$("0 messa(e to t%e C1 and if t%eincomin( relocation is not supported at t%e 24

side9 t%e C1 sends t%e (")OCA%$O&P("PA(A%$O& -A$)+(" messa(e 3it% t%iscause value.


preparation for

out(oin( C&inter-#AT

%andovers9relocation tar(et

not allo3ed

T%e measurement o,:ect of t%e counter is t%ecell. T%e counter is used to count t%e num,er oft%e inter-#AT C& domain %andover out(oin(preparation failures and t%e failure cause is(elocation %ar/et not alloed.

After t%e C sends t%e (")OCA%$O&("+$("0 messa(e to t%e C1 and if t%e D#1Cdoes not aut%orize t%e 6 to access t%e tar(etcell at t%e 24 side 9 t%e C1 sends t%e(")OCA%$O& P("PA(A%$O& -A$)+("

messa(e to t%e C 3it% t%is cause value.



inter-#AT

%andovers9 no

radio resourcesavaila,le in

tar(et cell


is used to count t%e num,er of t%e inter-#AT C&domain %andover out(oin( preparation failuresand t%e failure cause is &o (adio (esourcesAvaila!le in %ar/et Cell.

After t%e C sends t%e (")OCA%$O&("+$("0 messa(e to t%e C1 and if t%e D#1C

cannot allocate t%e radio resources due to %i(%load9 t%e C1 sends t%e (")OCA%$O&

P("PA(A%$O& -A$)+(" messa(e to t%e C

3it% t%is cause value.



30/57


Counter 0escription

1um,er of failed

relocationpreparation forout(oin( C&

inter-#AT

%andovers9 trafficload in t%e tar(etcell %i(%er

t%an in t%esource cell

T%e measurement o,:ect of t%e counter is t%ecell. T%e counter is used to count t%e num,er oft%e inter-#AT C& domain %andover out(oin(

preparation failures and t%e failure cause is%raffic )oad $n %he %ar/et Cell Hi/her %han$n %he ource Cell.

After t%e C sends t%e (")OCA%$O&("+$("0 messa(e to t%e C1 and if t%e load int%e tar(et cell is %i(%er t%an t%at in t%e sourcecell9 t%e 24 side re:ects t%e relocation requestand t%e C1 sends t%e (")OCA%$O&P("PA(A%$O&

-A$)+(" messa(e to t%e C 3it% t%is causevalue.



inter-#AT

%andovers9un


31/57


TA-$ " 3 !"$"*A#T C O U#T " !S ) U!I # T H" O UT O I # CS I #T " ! '!ATHA#)O * " ! O # T H" UU I#T " !F AC"

-ailure Course Course for Active et +pdate -ailure

Confi(urationunaccepta,le

If t%e %ard %andover of t%e 6 to t%e 24 cell is

decided to ,e made9 t%e #1C 3ill send t%e HA&0O4"( -(OM +%(A& COMMA&0 messa(e to t%e 69 and t%e messa(e includesmultiple


32/57


-ailure Course Course for Active et +pdate -ailure

+%(A& COMMA&0 messa(e to t%e 69 startt%e timer9 and 3ait for t%e $+ (")"A"COMMA&0 messa(e sent ,y t%e C1. If t%e

HA&0O4"( -(OM +%(A& COMMA&0messa(e or t%e response messa(e is lost durin(t%e transmission9 t%e timer at t%e #1C side 3ille?pire. And t%e #1C cannot receive t%e $+(")"A" COMMA&0 messa(e sent ,y t%e C19or t%e response a,out t%e failure from t%e 6.

Analysis of t%e eason for t%e

Out#oin# ', Inter-AT Hano!er

Failure

T%e out(oin( *& inter-#AT %andover does not %ave t%epreparation p%ase. T%e out(oin( *& %andover at t%e net3or<side is for t%e 6 in t%e C//DCH and C//FACH status9 and itinvolves out(oin( *& %andover process on t%e 6u interface andt%e conte?t information acquisition and transmission process att%e lu interface.

Out(oin( *& %andover on t%e 6u interface corresponds to t%eC")) CHA&" O(0"( -(OM +%(A& messa(e9 and t%e 6

starts t%e routin( area update flo3 to t%e 24 net3or< after itreceives t%e C")) CHA&" O(0"( -(OM +%(A& messa(e.T%en t%e &4&1 launc%es t%e conte?t information acquisition anddata transmission t%rou(% t%e lu interface. Conte?t Informationacquisition at t%e lu interface corresponds to t%e (&

CO&%"6% ("+"%# (&C CO&%"6% ("PO&" messa(e9and t%e data transmission process corresponds to t%e (&

0A%A -O(7A(0 COMMA&0 messa(e.

T%e follo3in( conditions indicate t%e out(oin( *& inter-#AT%andover failure.

!. T%e #1C receives t%e 6 C// CHA14 O#D# F#O7 6T#A1

FAI/ messa(e.2. If t%e out(oin( inter-#AT %andover is successful9 t%e cause

value of t%e $u (elease Command messa(e may ,euccessful (elocation or &ormal (elease. 0%en t%e #1Creceives t%e lu connection release command messa/e3it% cause value uccessful (elocation or &ormal(elease9 t%e out(oin( inter-#AT %andover is successful.

+. T%e inter-#AT %andover times out. If t%e 6 3ill ,e %anded

over to t%e 24 cell9 t%e #1C 3ill send t%e C")) CHA&"O(0"( -(OM +%(A& messa(e to t%e 69 start t%e timer9and 3ait for t%e (& CO&%"6% ("+"% messa(e sent,y t%e C1. If t%e C")) CHA&" O(0"( -(OM +%(A&



33/57


messa(e or t%e response messa(e is lost in t%e transmissionprocess9 t%e #1Cs 3aitin( 3ill time out9 and t%en t%e #1Ccannot receive t%e (& CO&%"6% ("+"% messa(edelivered ,y t%e C19 or t%e failure response from t%e 6.

TA-$ " 5 !" AS O #S F O ! T H" O UT O I # PS I #T " ! '!AT H A#)O * " ! FAI $ U!"

-ailure course Cause for Active et +pdate -ailure

Confi(uration

unaccepta,le

If t%e %ard %andover of t%e 6 to t%e 24 cell isdecided to ,e made9 t%e #1C 3ill send t%e C"))CHA&" O(0"( -(OM +%(A& messa(e tot%e 6. T%e messa(e includes multiple


34/57


-ailure course Cause for Active et +pdate -ailure

reason is not listed a,ove9 T%e content of t%efailure messa(e returned ,y t%e 6 isunspecified.

1o response

0%en t%e %andover of t%e 6 to t%e 24 cell isdecided to ,e made9 t%e #1C 3ill send t%e C"))CHA&" O(0"( -(OM +%(A& messa(e tot%e 69 and start t%e timer to 3ait t%e (&CO&%"6% ("+"% messa(e sent ,y t%e C1.If t%e C")) CHA&" O(0"( -(OM +%(A& messa(e or t%e response messa(e is lost durin(t%e transmission9 t%e 3aitin( at t%e #1C side3ill ,e timeout9 and t%e #1C 3ill receive neit%ert%e (& CO&%"6% ("+"% messa(e fromt%e C1 nor t%e failure response from t%e 6.



35/57

C h a p t e r +

Cases of Handover

Performance Optimization

Cases of Intra-AT

Hano!er Optimization

Hano!er Failure an Call DropCause &y Corner (ffect

*ro,lem Description

Accordin( to t%e CNT test9 t%e en(ineer finds t%e call drop 3%en

t%e elevator is opened or closed at some indoor distri,uted sites.

Analysis

T%e main reasons include t%at t%e nei(%,orin( cell relation,et3een t%e cells inside and outside of t%e elevator is improperly

set9 and t%e %andover is not processed in time. After t%erepeated continuous callin( test in t%e elevator 3%ere t%e calldrop %appens9 t%e en(ineer finds t%at t%e call drop %appens att%e moment of t%e elevator ,ein( closed. And t%e test s%o3st%at t%e nei(%,orin( cell relation ,et3een t%e cell inside andoutside t%e elevator is properly set9 so t%e reason of t%e call

drop may ,e t%e fact t%at t%e %andover is not processed in time.

T%e follo3in( fi(ure s%o3s t%e si(nalin( outside of t%e elevator93%ic% is mainly covered ,y t%e cell 3it% *&C +"$.



36/57

F I U ! " 15 S I #A$ I # O UT O F T H" "$"*ATO! -" F O !" O P T I M I ; AT I O #

T%e si(nalin( of t%e scram,lin( +>$ cell ,ecomes stron(er at t%emoment t%e 6 enters t%e elevator and its door is ,ein( closed9as s%o3n in t%e follo3in( fi(ure.

F I U ! " 16 S I #A$ I # I # T H" "$"*ATO! -" F O !" O P T I M I ; AT I O #

Accordin( to t%e test si(nalin(9 t%is $ cell is not includedt%e active set in time9 3%ic% causes t%e call drop.



37/57

C%apter 2 Cases of Handover *erformance Optimization

F I U ! " 18 A#A$%SIS O F T H" CA$ $ )!O P CAUS " ) -% CO !#" ! " F F " CT

Optimization *lan

ecause t%e area around t%e elevator is covered ,y t%e indoordistri,uted sites9 it is difficult to reconstruct t%e indoor antenna

and feeder system. &o t%e optimization can ,e done ,ymodifyin( t%e parameters. T%e (eneral optimization plan is t%at

t%e *&C+>$ cell s%ould report vent !A as soon as possi,le toenter t%e active set. In order to ma


38/57


39/57


Hano!er Failure an Call Drop

Cause &y 'inpoint (ffect

*ro,lem Description

In moment !9 t%e cell p%one moves alon( t%e route s%o3n ,yt%e red arro39 and t%e %andover failure and call drop of t%e

voice service %appen. T%e t3o related cells are GC6*&C$B and GCOO"6 *&C)+B. At t%e ,e(innin(9 t%e cell is in

t%e macro diversity status9 t%e main servin( cell is t%e t%ird cell*&C)+B of site GC"69 and t%e pilot quality c=Io is -'.$+d.

F I U ! " ++ H A#)O * " ! A# ) CA$ $ )!O P CAUS " ) -% P I #P O I #T " F F " CT .T H" M AI # S " !* I C" C" $ $ I S PSC20 I # M O M " #T 1 /

In moment 29 t%e main servin( cell of t%e 6 is c%an(ed to ,et%e t%ird cell *&C$B of GC69 and t%e pilot quality c=Io is

-!.+! d. T%e t%ird cell *&C)+B of GC"6 leaves t%e activeset and appears in t%e monitorin( set.



40/57


F I U ! " +0 H A#)O * " ! A# ) CA$ $ )!O P CAUS " ) -% P I #P O I #T " F F " CT .PSC20 C" $ $ $"A*"S T H " ACT I * " S " T I # M O M " #T + /

In moment +9 after one second9 t%e si(nal quality of t%e t%irdcell *&C)+B of GC"6 is stron(er t%an t%at of t%e t%ird cell*&C$B of GC69 and t%e c=Io is -2.+' d. And t%e t%ird

cell *&C)+B of GC"6 reports vent !A and tries to entert%e active set a(ain. Ho3ever9 as t%e main servin( cell9 t%e t%ird

cell *&C$B of GC6 %as poor pilot quality9 and t%e c=Io is-2!.) d. As s%o3n in t%e follo3in( fi(ure9 after t%e 6 reportsvent !A9 t%e do3nlin< cannot receive t%e %andover command9and finally t%e call drop %appens.

F I U ! " + H A#)O * " ! A# ) CA$ $ )!O P CAUS " ) -% P I #P O I #T " F F " CT .CA$ $ )!O P HAP P " #S -" CAUS " T H" PSC20 C" $ $ CA##O T ,O I # I # T H " ACT I * " S "T I #

M O M " #T

0 /

Analysis

T%is is t%e typical call drop caused ,y t%e *inpoint effect. T%esi(nal of *&C$ cell ,ecomes stron(er suddenly9 3%ic% ma


41/57


it %ard for *&C)+ cell to tri((er vent ! and leave t%e activeset.

F I U ! " +2 H A#)O * " ! A# ) CA$ $ )!O P CAUS " ) -% T I P " F F " CT

Optimization *lan

In order to prevent t%e situation t%at t%e call drop %appens,ecause it is difficult for t%e t%ird cell *&C)+B of GC"6 to

enter t%e active set a(ain after it leaves t%e active set9 t%eCellIndivOffset utranCellB of t%e t%ird cell *&C)+B of GC"6in t%e active set s%ould ,e modified from to + d9 so t%e cell3ill remain in t%e active set.

Optimization #esult

After modifyin( t%e parameter9 t%e en(ineer finds t%at t%e calldrop point disappears in t%e test. In t%e call %old status9 t%e 6

still moves alon( t%e arro3s direction9 and t%e main service cellis t%e t%ird cell *&C)+B of GC"6.

F I U ! " +3 MAI # S " !* I C" C" $ $ PSC20

/ater9 t%e si(nal quality of t%e t%ird cell *&C)+B of GC"6,ecomes poor9 and t%e c=Io is -!+.2+9 3ea


42/57


F I U ! " +5 MAI # S " !* I C" C" $ $ C H A # " ) T O - " PSC6

Finally9 *&C)+ cell is t%e main service cell a(ain9 as s%o3n in t%efollo3in( cell9 and t%e call drop disappears.

F I U ! " +6 MAI # S " !* I C" C" $ $ C H A # " ) T O - " PSC20


Cause &y Insufficient ',C euse

Distance

*ro,lem Description

In t%e 3%ole-net3or< optimization process near t%e ai&%ii in

8iu/on(*o district of C%on(Nin(9 call drop %appens in every test



43/57


on t%e road near i uan #estaurant. T%e specific locations ares%o3n in t%e follo3in( fi(ure.

F I U ! " +8 C A$ $ )!O P #" A! % I %U A# !" S T AU!A#T

Analysis

First9 c%ec< t%e si(nal covera(e in t%e area 3%ere t%e call drop%appens9 and t%e en(ineer finds t%at t%e si(nal covera(estren(t% and t%e si(nal quality are (ood in t%is area accordin( tot%e drive test. T%e si(nal stren(t% is around -") dm9 and t%esi(nal quality is a,out -> d. 0it% t%is


44/57


F I U ! " 09 ) I S T !I -UT I O # )I A !AM O F T H" #O ) "- A# ) S C!AM -$ I # #" A! % I %UA# ! " S T AU!A#T

From t%e a,ove fi(ure9 t%e en(ineer finds t%at t%e scram,lin( ati uan #estaurant is t%e same 3it% t%ose of t%e 1odes ateiDiiuan and 5ou7aTaoHua/in *&C"'B9 and t%e distance,et3een t3o sites is less t%an )


45/57


46/57


F I U ! " 0 ! " P O !T " ) "* " #T 1-

T%e call drop %appens ,efore t%e 6 deletes *&C"$ from t%eactive set. T%en9 t%e 6 sends t%e cell update messa(e9 and

t%e reason is radiolin* failure.

F I U ! " 02 C A$ $ )!O P CAUS " ) - % O UT O F S % #C O F T H" !A)I O $ I #4

C%ec< t%e recent t3o measure reports ,efore t%e call drop9 t%esi(nal quality of *&C"' is (ood.

mode&pecificInfo fdd ;

Q

primaryC*ICH-Info

Q

primary&cram,lin(Code "'

R9

cpic%-c-1 9



47/57


cpic%-#&C* 2$

R

mode&pecificInfo fdd ;

Q

primaryC*ICH-Info

Q

primary&cram,lin(Code "'

R9

cpic%-c-1 9

cpic%-#&C* ++

R

T%e reason of radio lin< failure is analyzed as follo3s; T%e 6reports vent !A after measurin( cell2>'!+ *&C"'B9 ,ut t%e

#1C esta,lis%es one #/ in cell2"22 *&C"'B accordin( to t%enei(%,orin( cell relations%ip. T%e 6 measures t%e FrameOffset

of cell2>'!+9 ,ut uses t%e FrameOffset in cell2"229 3%ic%causes t%e out of sync of t%e #/ node.

Optimization *lan

From t%e Fi(ure + 9 t%e en(ineer can vie3 t%at t%ere isscram,lin( reuse in t%e area 3%ere t%e call drop %appens.T%rou(% t%e su,sequent si(nalin( analysis9 t%e en(ineer


48/57



Cause &y imite ,ystem

esources

*ro,lem Description

T%e ,ac


49/57


50/57


F I U ! " 05 S IT " )I A !AM O F T AI $ AM T U##" $

*ro,lem Analysis and Optimization *lan

In t%is scenario9 t%e user enters t%e 24 covered area from t%e+4 covered area outside of t%e tunnel at a %i(% speed. T%e(eneral optimization plan is to let t%e users %andover from +4

net3or< to 24 net3or< ,ecome quic< enou(%. Durin( t%e periodof middle and late 7ay9 t%e en(ineer tried t%ree


51/57


52/57


$nde

Be/in%ime

"nd%ime

%imeranularity

CellCall0rop

(ate9C

&um!erOfCall0rop9C

&um!er Ofuccessful(AB"sta!lishment9C

(emar*

Tactic U !vent +Atri((erB+A6trancellU -')@

' 2'-)-!'

2'-)-2

2Hours

2.$W

)+ 22"+ For F!=F+cells2D=2F U-')=-$)@Hys2d=Hys2f U =@TTT2d=TTT2f U >ms=> ms@Inter-#ATHandoverTactic U !vent +Atri((erB

+A6trancellU -')@+AOt%er#atU -'@ HysU@ TTT+AU ! ms

!2'-)-2

2'-)-2!

2Hours

2.$'W

>> 2$!

!!2'-)-2!

2'-)-22

2Hours

2."W

)! 2!"

!22'-)-22

2'-)-2+

2Hours

2.>2W

>" 22+

!+2'-)-2+

2'-)-2

2Hours

2.!!W

>" 2">$

!2'-)-2

2'-)-2)

2Hours

2.>W

>+ 22')

!)2'-

)-2)

2'-

)-2>

2

Hours

).>

'W!') +!>)

T%e 3ron(

sequence oft%e imported

parametertemplate

causes t%efailure of t%e

%andoverfrom +4 to

24

!>2'-)-2>

'-)-2"

2Hours

$.!+W

+!> +''

!"2'-)-2"

2'-)-2$

2Hours

!.2)W

) +)+For F!=F+cells2D=2F U-'=-$@Hys2d=Hys2f U =@TTT2d=TTT2f U >ms=> ms@Inter-#ATHandover

Tactic U

!$'-)-2$

2'-)-2'

2Hours

.'!W

2" 2>2

!'2'-)-2'

2'-)-+

2Hours

!.+'W

)) +)+$

22'-

)-+

2'-

)-+!

2

Hours

!.

+W2 +>>$

2! 2'- 2'- 2 !.! + 2"+



53/57


$nde

Be/in%ime

"nd%ime

%imeranularity

CellCall0rop

(ate9C

&um!erOfCall0rop9C

&um!er Ofuccessful(AB"sta!lishment9C

(emar*

)-+! >-! Hours 2W

2vent +Ctri((erB+COt%er#atU -')@ Hys U

222'->-!

2'->-2

Hours

!.+$W

)> +)'!

2+2'->-2

2'->-+

2Hours

!.2W

)" +>+>

From t%e c%an(e of t%e G*I of t%e &6T call drop9 t%e en(ineercan 9 and t%e call drop rate is

!"WX!'W@ 2D=2FU-')=-$)9 and t%e call drop is 2WX+W@2D=2FU-'=-$9 and t%e call drop is !WX!.W. T%erefore9 t%e

settin( of parameter 2D=2FU-'=-$ is suita,le for t%e &6T int%e scenario of fast %andover from +4 to 24. If t%is suit of parameter uses vent +A tri((er9 t%e correspondin( t%res%olds%ould ,e ad:usted. T%e +C event tri((er can also ,e used.

Hano!er Failure Cause &y /ron#

Confi#uration of Intra-AT

$ei#%&orin# cells

*ro,lem Description

On a main road from nort% to sout%9 t%e inter-#AT %andoverfrom &C2" GHTG+B cell failed9 3%ic% caused t%e call drop9 ass%o3n in t%e follo3in( fi(ure.

F I U ! " 08 C A$ $ )!O P CAUS " ) - % T H " I #T " ! '!AT HA#)O * " ! F AI $ U!"

Analysis



54/57


T%e ,ac


55/57


F I U ! " 1 ACT UA$ SM C" $ $ I #F O !M AT I O # .-CCH


56/57


F I U ! " 0 - AC4 !O U#) S I #A$ I # 1

Analysis

From t%e ,ac


57/57


!. First9 t%e (outer +pdate (e,uest messa(e is not found att%e 2-&4&1 terminal9 &ut2 !iein# from t%e 3u interface2 t%een#ineer fins t%at t%e 3( sent t%is messa#e. Actually2 4-,,$terminal can only recor some simple si#nalin#2 &ut it cannot trace t%e

si#nalin#. T%erefore2 t%is p%enomenon oes not necessarilyrepresent t%at 4-,,$ i not recei!e t%e messa#e completely.

2. &uppose t%at 2-&4&1 received t%e (outer +pdate (e,uestmessa(e in t%e last step9 and t%en c%ec< 3%et%er t%e ne3 2-

&4&1 sent t%e & Contet (e,uest messa(e to t%e old+-&4&19 and 3%et%er t%e old +-&4&1 received t%is messa(e.

T%e result s%o3s t%at t%e ne3 2-&4&1 terminal does not %ast%e record of sendin( t%is messa(e9 and t%e reason is t%esame 3it% t%at demonstrated in t%e last step9 3it% not%in(ne3 in t%is. At t%e same time9 t%e old +-&4&1 terminal doesnot %ave t%e record of receivin( t%is messa(e9 ,ut t%isterminal can s%o3 t%e si(nalin( in detail. T%erefore9 t%is

pro,lem locates at t%e transmission of t%e & Contet(e,uest messa(e ,et3een 2-&4&1 and +-&4&1.

0%at is more9 :ud(in( from t%e reason 7& identity cannot,e derived ,y t%e net3or

Documents

3 WCDMA a en UMTS Handover Optimization 1 WORD 201005 59