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Handover Process
HO parameters and optimization reated toHO process in !"M net#or$
No$ia Net#or$s
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Handover Process 1/2
Hando'er decisions( made )* ++ Mana,ement in -"( are )ased on temeasurement resuts reported )* te M" / -T"( parameter sets 0or eacce and a,oritms. Tar,et ce e'auation is aso one part o0 teando'er process. Hando'ers are tri,,ered o )* tresod comparisonor )* periodic comparison.
Tar,et ce e'auation is made in ++ Mana,ement in -" and its purposeis to 2nd te )est ce 0or ando'er. Te e'auation on te pre0erred ist o0te tar,et ces is )ased on3
Te radio in$ measurements Tresod comparison
Te priorit* e'es o0 te nei,)ourin, ces
Te oad o0 te nei,)ourin, ces #ic )eon, to te same -" as teser'in, ce.
+4 e'e comparison 5 i0 it is needed
Te -T" sends te ist o0 )est candidates to te -". 6irst te -"de2nes and seects tose ces( #ic meet te re7uirements 0or teradio in$ properties. ++ Mana,ement can ande up to 8% )estcandidates 0or tar,et ce e'auation.
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Handover Process 2/2
-"
Eq. 1or
Eq. 1'
Adj1..Adj2.
Adj3.--------------------------------------------------------Adj32
Adj1Adj3------------------Adjn
Eq.2or
Eq.2'
Target Cell Evaluation
Cell ranked according to priority/load
Adj1Adj3-------Adji.
oad in!or"ation!ro" t#e $$"anage"ent
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HO&PC Diagram
%
1
2
3
&
(
)
-11% -1% -1%% -* -*% -+ -+% -) -)% -( -(% - -%
PcUpperThresholdQualUL/DL
HoThresholdQualUL/DL
Power decrease
Power increase
Noactionneeded
Interference HoQuality Ho
LevHo
PcLevUpperThresholdLevUL/DL
HoThresholdLevD
PcLowerThresholdLevUL/DL
HoThresholdInterferenceUL/DL
PcLowerThresholdQualUL/DL
HoThresholdLevUL (if diversity gain
!"Lev#in$ell(n
!"Lev%cc#in
Power increase
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Handover Priority
Hando'er priorit*
1. ;pin$ and do#nin$ Inter0erence%. ;pin$ 7uait*8. Do#nin$ 7uait*
9. ;pin$ e'e:. Do#nin$ e'e. "o# mo'in, M"?. -etter ce i.e. Periodic cec$ @Po#er -ud,et HO or ;m)rea H
1B. P3 Co#er 7uait*/e'e tresods @;C/DC11. P3 ;pper 7uait*/e'e tresods @;C/DC
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Handover Types 1/2
Intra e HO
Hando'er in same T+ )et#een dierent timesots ontroed )* -"
Intra "ite HO Hando'er )et#een dierent sectors in same site ontroed )* -"
Inter "ite HO Hando'er )et#een sectors o0 dierent sites ontroed )* -"
Inter -" HO Hando'er )et#een sectors o0 dierent sites and dierent -"s ontroed )* M"
Inter "*stem HO Hando'er )et#een t#o M"s ontroed )* M"
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Handover Types 2/2
target
MSC 1
MSC 2
MSC controlled
BSC 1
outgoing
intra
cell inter BSC source
BSC 2incoming
intercell
MSC controlled
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Handover Syncroni!ation
Site "
Site B
"*ncronised HO )et#een co-6 ces
Nons*ncronised HO )et#een dierent sites
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HO "lgorit#ms
$%uation 1AFG+CEFGNECC@n r'(evMinCell)n* Ma4 @B( AA J msT'P+rMa')n* P P J dependin, on M" assmar$
$%uation 2
P-!T #oMarginPB,T)n* #ere
P-!T J ))msT'P+rMa' msT'P+rMa')n**@AFG+CEFGDCGHO
AFG+CEFGNECC@n
@-tsT'P+rMa' -T"GTP+$%uation 2.@I0 ena-leHoMargin(evual J LP-!T #oMargin(ev/ual)n* #ereP-!T J @AFG+CEFGNECC@n AFG+CEFGDCGHO@-tsT'P+rMa'-T"GTP+AFG+CEFGNECC@n3 A'era,ed recei'in, e'es o0 adacent ces
AFG+CEFGDCGHO3 A'era,ed recei'in, e'e o0 ser'in, ce)tsT4P#rMa43 Transmittin, po#er e'e o0 ser'in, ce
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Po+er Budget Handover 1/2 Tri,,er
Periodic ec$ @ #oPeriodPB,T
andidate "eection E7uation 1 &% used Priorit* and Coad onsidered
T*pica* used )et#een ces o0 te same Ca*er
Parameters Faue HOPeriodPB,T 0 3 S"CCH periods ena-leP+rBudgetHandover 4 / 5 r'(evMinCell)n* 110 67 dBm msT'P+rMa')n* 0 30 dBm #oMarginPB,T)n* 0 3 dBm
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Po+er Budget Handovers 2/2
P-!T J @@msT'P+rMa' msT'P+rMa')n @AFG+CEFGDCGHOAFG+CEFGNEC
@-tsT'P+rMa' -T"GTP+
P-!T J @@8Bd-m8Bd-m@?B >B@9%d-m9%d-m J 1B d-
1B d- < d- OK
AFG+CEFGNECC@n r'(evMinCell)n* Ma4 @B( msT'P+rMa')n* msT'P+r
>B d-m ?? d-m @8B d-m 8B d-m J ?? d-m
1.
%.
AFG+CEFGDCGHO J ?B d-mmsT'P+rMa'J 8B d-m @J 1-tsT'P+rMa' J 9% d-m @J 1< -T"GTGP+ J 9% d-m J @1< #oMarginPB,T)n*J < d-
"er'in, e3 -est Adacent e3
AFG+CEFGNECC@n J >B d-mr'(evMinCell)n*J ?? d-mmsT'P+rMa')n*J 8B d-m @J 1-tsT'P+rMa'J 9% d-m @J 1<
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(evel Handover 1/2
Tri,,erTresod omparison @ #oT#res#olds(ev8(/D()p' n'
andidate "eection E7uation 1 used E7uation % used i0 ena-leHoMargin(evual J N E7uation % #it#oMargin(evused i0ena-leHoMargin(evual J L Priorit* and Coad onsidered #itin te same -"
Parameters HOT#res#old(ev8(/D( 110 67 dBm
p' 1 32 n' 1 32
r'(evMinCell)n* 110 67 dBm msT'P+rMa')n* 0 30 dBm
#oMargin(ev)n* 26 26 dB
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(evel Handover 2/2
E7uations 1 and % are used i0 parameter ena-leHoMargin(evual is set QLesR
% d-
#oMargin(evJ 9 d-
Tri,,er 0or Hando'er due to Ce'e
A
-
J e - is not seected as candidate 0orHO due to e'e since %d- S 9 d-
Tresod @Ce'?: d-m
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uality Handover 1/2
Tri,,erTresod omparison @ #oT#res#oldsual8(/D()p' n'
andidate "eection E7uation 1 used E7uation % used i0 ena-leHoMargin(evual J N E7uation % #it#oMarginualused i0ena-leHoMargin(evual J L Priorit* and Coad onsidered
Parameters Faue HOT#res#oldual8(/D( 0 7
p' 1 32 n' 1 32
r'(evMinCell)n* 100 67 dBm msT'P+rMa')n* 0 30 dBm
#oMarginual)n* 26 26 dB
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uality Handover 2/2
E7uations 1 and % are used i0 parameter ena-leHoMargin(evual is set QLesR
% d-
#oMarginualJ B d-
Tri,,er 0or Hando'er HO due to uait*
A
-
J e - is seected as potentia candidate 0or HO due to uait* since % d- B d-
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Signal uality in ,SM
+ uait* @+;AC parameter
+;AC casses B ... =,it error rate beforeall decoding/ correction
$0A ean E$ E$ range
cla 45 !ro"... to
% %61& 7 %6241 %62+ %62 ... %6& 4
2 %6) %6& ... %6+ 4
3 1613 %6+ ... 16( 4
& 262( 16( ... 362 4
&63 362 ... (6& 4
( *6% (6& ... 126+ 4) 1+61 8 126+ 4
ua,le ignal
unua,le
ignal
good
accepta,le
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Handover Due To 9nter:erence
Tri,,er 3 Tresod omparisonTresod omparison 0or uait* @ #oT#res#oldsual8(/D()p' n'*
Tresod omparison 0or Ce'e @ #oT#res#olds9nter:erence8(/D()p' n'* andidate "eection
Priorit* 0or Intere / Intrace HO seected at -" independent* 0or ;C / DC Priorit* Intere HO
uait* HO i0 an* candidate I0 not Intrae HO
Priorit* Intrae HO
Parameters Faue #oT#res#old9nter:erence8(/D( 110 67 dBm
p' 1 32 n' 1 32
ena-le9ntraHo9nter:8(/D( 4 / 5 #oPre:erenceOrder9nter:8(/D( 95T$; / 95T;"
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9mperative Handovers
Imperati'e Hando'ers Hando'er due to Distance Order to empt* ce( 0rom NM" Directed +etr* or ID+ +apid 6ied Drop
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Handover Due To Distance
Distance Process msDistanceBe#aviour@B(1..
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Directed ;etry
Directed +etr* Directed retr* is ando'er 0rom ser'in, ce "DH to an
adacent ce TH durin, ca setup ;sed #en TH con,estion is disa)in, TH assi,nment Ena)ed )* parameter dr9n8se
Parameters Faue dr9n8se 4 / 5
DrT#res#old 110 67 dBm
Handover Due To ;apid >ield
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Handover Due To ;apid >ieldDrop
Tri,,erTresod omparison @ HoT#res#old;apid(ev8l@p'
+4GCe'G;C @Not a'era,ed / On* ;C andidate "eection
On* ained adacent ce E7uation 1 on* / no priorit*
MutiCa*ered Net#or$
Parameters Faue
HOT#res#old(ev8(:or;apid>ieldDrop 110 67 HOT#res#old;apid(ev815 0 32 c#ained"d?acentCell 4 / 5
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HO Parameters 1/
9ntervalsmin9ntBet+eenHo;eg
Pre'ents repetiti'e ando'ers 0or te same M" #it a timer tat setste minimum inter'a )et#een ando'ers
Min9ntBet+een8nsuccHo"ttemptIndicates te minimum time tat M" must #ait a0ter ando'erattempt 0ais and )e0ore it can tr* a ando'er attempt a,ain
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HO Parameters 2/
;adio ;esource Parameters
-ts(oadT#res#oldec$s te oad tresod ratio o0 candidate ces
#o(evPriority
De2nes te priorit* e'e o0 an adacent ce to account 0or ocation
#o(oad>actor
De2nes o# muc te priorit* e'e #i )e decreased #en te oad
tresod is e4ceeded
msSpeedt#res#old5'/P'
ompares speed tresod 'aues
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HO Parameters 3/
Po+er Budget Parameters
Po+er -udget #andover procedure ensures t#at t#e MS is al+ays#anded over to t#e cell +it# t#e minimum pat# loss
e'en tou, te 7uait* and te e'e tresods ma* not a'e )eene4ceeded
$na-lePo+erBudgetHO
Indicates i0 po#er )ud,et is used as a criterion 0or a ando'er
HoPeriodPB,T
-" e'auates adacent ces tar,et ce 0or te ando'er at e'er*de2ned "AH inter'a
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HO Parameters 6/
uality (evel Parameters
HoT#res#oldsual8(/D(compares te a'era,ed 'aues o0 "@;A8"( or"@;A($@
;'ual is te tresod e'e 0or ando'er.
The range is 12.8% bit error rate
5'is te tota num)er o0 a'era,es to )e ta$en into account )e0oredecision is possi)e.
The range varies from 1 to 32P'is te num)er o0 a'era,es out o0 tota a'era,es tat a'e to )e,reater tan or e7ua to te tresod )e0ore a ando'er is possi)e.
The range varies from 1 to 32
O
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HO Parametrs =/
MS to BTS Distance
en distance is te reason 0or te ando'er re7uestmsDistanceBe#aviour contros te )ea'iour o0 te M"
Tere are tree aternati'es in #ic te Mo)ie #i act in te case o0 tisImperati'e Hando'er3
It #i reease te ca immediate*
Tr* a 1 to
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HO Parametrs /
S#aring t#e (oadT#e MSC may re%uest t#e BSC to per:orm a specied num-er o:
#andovers :rom one specied cell :or load s#aringIt is possi)e to ando'er to U#orse ces
T#e eld strengt# in t#e ad?acent cell #as to -e a-ove t+o parameterr'(evMinCelltr#oTarget(evel
The target cells are only ranked according to radio link roerties
riority levels are not !sedThe feat!re is disabled by setting the val!e to "not !sed"
5 t D t ; t
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5et+or Doctor ;eports
;se0u Hando'er Net#or$ Doctor reports 0or HO optimization andana*sis
1:B( es a'in, i, HO 0aiure ratio 1:8( Adacencies a'in, i, HO 0aiure ratio 1:9( Hando'er cause distri)ution 1:=( es a'in, i, HO att./ca ratio 1:>( Intra -"" ando'er o)ser'ation statistics
Oter ND reports 0or HO ana*sis&studies B
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Handover >lo+c#arts
Handover >ailure
New Channel, New Cell
H"5DO@$; CMD
"CT9@$ C"((
MS 5$TDO;E
H"5DO@$; >"9(
"CT9@$ C"((
Old C#annel< Old Cell
Old C#annel< Old Cell
Timer T3126 e'piry or;adio (in >ailure
S i d H d
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Syncroni!ed Handover
5e+ C#annel< 5e+ Cell
"CT9@$ C"((
H"5DO CMD
H"5DO "CCH"5DO "CC
H"5DO "CC
H"5DO "CC
H"5DO COM
"CT9@$ C"((
MS5$TO;E
Old C#annel< Old Cell
Serving BTS 5eig#-or BTS
)>"CCH*
)>"CCH*
)>"CCH*
)>"CCH*
)>"CCH*
)>"CCH*
5on S ncroni ed Hando er
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5onSyncroni!ed Handover
5e+ C#annel< 5e+ Cell
MS5$TO;E
"CT9@$ C"((
H"5DO CMD
H"5DO "CC F
H"5DO "CC
PH4S 95>O
PH4S 95>O
H"5DO COM
"CT9@$ C"((
Old C#annel< Old Cell
N*1
Serving BTS Serving BTS
T3126)in MS*
Handover "nalysis
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Handover "nalysis
ic$ ere to ,o HO ana*sis Vo#cart
ompare Net#or$ on2,uration a,ainst Net#or$ Desi,n
Adacencies to None4istin, es
Nons*mmetrica Adacencies
Adacent e #it same or adacent 6re7uenc*
"*ncronised HO Adacenc* Discrepancies
-T" De0aut Parameter Audit
Drive Test "nalysis 1/2
http://ho%20analysis%20chart.ppt/#Handover%20Priorityhttp://ho%20analysis%20chart.ppt/#Handover%20Priority7/23/2019 HO Process&Optimization
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Drive Test "nalysis 1/2
I0 dri'e test data a'aia)e 6ind a te HO6 0aiures usin, ana*sis toos "tud* reason 0or HO 0aiure usin,
!rapica data pro'ided )* ana*sis too Ca*er 8 messa,es pro'ided )* ana*sis too NM" data @ND reports
ommon reasons 0or HO 0aiures Hando'er e4ecuted too ate @source ce 7uait* or inter0erence aread* too
)ad
HOP-!T mar,in( HOCe'e( HO #indo# a'era,in, size Tar,et ce 7uait* )ad( cant ma$e HO sta*s at od canne 6re7uenc* pannin,( co'era,e/dominance area pannin,
No ,ood ce to ma$e HO o'era,e pannin,( ac$ o0 sites or azimut/tit/antenna optimization
Hard#are 0aiure HO timer e4pires -T"/T1 s*ncronization pro)em
Discrepancies in -T"/-" parameters ec$ a -T" parameters @I( -"I( CA( -"( 6re7.( Adacencies(
HO parameters #it ND reports/NM" comparin, to rea dri'e data.
Drive Test "nalysis 2/2
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Drive Test "nalysis 2/2
A0ter dri'e test data and NM" report ana*sis pan neededparameter can,es.
E4ecute can,e re7uests impementin, ne# parameter 'auesusin, NM".
Ma$e ne# dri'e test at same area a0ter parameter can,es or i0not possi)e stud* NM" data #it ND reports @needs rea traWc.
"tart ana*sis and stud* i0 more can,es are re7uired.
Hando'er 0aiure does not necessari* mean drop ca it can stista* at od canne and ma$e ne# HO attempt ater eiter tosame adacent ce or some oter adacent ce.
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