bsspar chapter 07 intelligent underlay overlay mo

8/14/2019 BSSPAR Chapter 07 Intelligent Underlay Overlay MO

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Nokia Networks Oy 1(25)


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Intelligent Underlay Overlay

The information in this docment is s!"ect to change withot notice and descri!es only the#rodct defined in the introdction of this docmentation$ This docment is intended for these of Nokia Networks% cstomers only for the #r#oses of the agreement nder which thedocment is s!mitted& and no #art of it may !e re#rodced or transmitted in any form ormeans withot the #rior written #ermission of Nokia Networks$ The docment has !een

#re#ared to !e sed !y #rofessional and #ro#erly trained #ersonnel& and the cstomerassmes fll res#onsi!ility when sing it$ Nokia Networks welcomes cstomer comments as#art of the #rocess of continos develo#ment and im#rovement of the docmentation$

The information or statements given in this docment concerning the sita!ility& ca#acity& or#erformance of the mentioned hardware or software #rodcts cannot !e considered !inding!t shall !e defined in the agreement made !etween Nokia Networks and the cstomer$'owever& Nokia Networks has made all reasona!le efforts to ensre that the instrctionscontained in the docment are adeate and free of material errors and omissions$ NokiaNetworks will& if necessary& e#lain isses which may not !e covered !y the docment$

Nokia Networks% lia!ility for any errors in the docment is limited to the docmentarycorrection of errors$ Nokia Networks *I++ NOT ,- .-/0ON/I,+- IN N -3-NT 4O.-..O./ IN T'I/ O6U7-NT O. 4O. N 78-/& IN6I-NT+ O.6ON/-9U-NTI+ (IN6+UIN8 7ON-T. +O//-/)& that might arise from the se of thisdocment or the information in it$

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6o#yright Nokia Networks Oy 2;;


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Contents

7 Intelligent Underla !"erla #

Nokia Networks Oy =(25)


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7 Intelligent Underla !"erla

7$% &odule !'ecti"es

t the end of the modle the #artici#ant will !e a!le to>

8ive an overview a!ot the organi?ation of an IUO network& and how

this is com!ined with the se of micro cells and freency ho##ing

-#lain& how IUO effects T6' allocation for call set #& directed retry

and conventional handover

emonstrate& how the 6@I ratio is estimated and whichmeasrements are reired for this

iscss IUO s#ecific handovers like IUO handover and direct access

7$2 Introduction

7$2$% Idea

Intelligent Underlay Overlay IUO is an optional N!I* specificfeatreto enhance the network ca#acity !y an increased freency rese$ The!asic idea is to divide the o#erating freency s#ectrm into twofreency sets& the regularand the super reusefreencies$ *hile forthe reglar freencies a conventional rese scheme is sed& the s#errese freencies are resed very intensively$

7$2$2 +egular and ,uper +euse -aer

ccording the two freency sets there are also two network layers& theo"erla network !ased on the reglar freencies& and the underlanetwork !ased on the s#er rese ones$

7$2$2$% ,imple &acro Cell Networ.

The overlay network consists of overla##ing cells& for which aconventional freency rese is sed& so that ad"acent and coAchannelinterference is ke#t low$ It #rovides the initial T6' after call set # and


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generally serves 7/s for which the 6@I conditions are !ad (e$g$ at thecell !ondaries)$ Ths the overlay network gives access to the IUOnetwork and #rovides continos coverage$ 0hysically it is reali?ed !ythe so called regularT.Bs$

The nderlay network is reali?ed !y so called super reuseT.Bs$ In acell& the s#er rese T.Bs se the same antennas and the sametransmission power le"els as the reglar T.Bs$ Ths the nderlaynetwork offers the same co"erage as the overlay network$ 4or thenderlay network& however& there is a much tighter fre/uenc reuse&and therefore a higher interference level$ /o after call set # the 7/ will!e handed over to the nderlay network& if the 6@I ratio is good enogh(e$g$ if the 7/ is close to the ,T/)$ If the 6@I ratio falls !elow a certainlimit& the 7/ is handed over !ack to the overlay network again (or a!etter s#er rese T.B)$ The 6@I ratio is determined !y the ,/6 on the!asis of the measrement re#ort& which is e#lained later in this cha#ter$

The modelling of IUO networks shows& that a sfficient 6@I can !eo!tained for most of the covered area$

s already mentioned& sally a cell is ei##ed !oth with reglar ands#er rese T.Bs$ This division is controlled !y the #arametertr01re/uencTpe (1+T)(T+)(3$$%4)(3)$ The defalt setting indicates areglar T.B$ Otherwise the s#er rese freency gro# of the s#errese T.B is indicated$ T.Bs !elonging to the same s#er resefreency gro# have the same sorce of interference$ In one cell& thes#er rese T.Bs may !elong to the same or different freencygro#s$ The !asic strctre of an IUO network is de#icted !y 4ig$ C A1&an eam#le for an interference model is given !y4ig$ C A2$

NOKIA BSSPAR / 10.05.2004

IntelligentUnderla!"erla

Regular / Super Reuse Layer(Simple Macro Cell Network)

Regular Layer(grey)

Normal freency rese/##orts call set #/erves 7/ nder !ad 6@I conditions (e$g$ cell !ondary)

Super Reuse Layer (green)

Tight freency rese/erves 7/ nder good 6@I conditions (e$g$ close to the,T/)

Control of T+ tpe

tr4reencyTy#e ;$$1D ; E reglar T.B1A1D E s#er resefreency gro# of T.B



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4ig$ CA1> .eglar @ s#er rese layer (sim#le macro cell network)

NOKIA BSSP AR / 10.05.2004

regular frequencies - c!erage la"er su#er reuse frequencies - ca#aci$" la"er

IntelligentUnderla!"erla Regular / Super Reuse Layer(Interference)

green% &ig& in$erference - '/I (12 )Bsu#er reuse la"er can *e use) fr +s$f $&e c!ere) area

4ig$ CA2> .eglar @ s#er rese layer (interference)

The ca#acity gain !y IUO can !e a!ot 1@=& as shown !y the followingeam#le (see 4ig$ C A=)$ 6onsider an ordinary network with =Dfreencies& rese E 12 and = T.Bs #er cell$ If we divide the =Dchannels into 2< reglar and 12 s#er rese ones& we can se < T.Bsfor each cell> 2 reglar ones (rese E 12l) and 2 s#er rese T.Bs(rese E D)$

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a!aila*le *an),i)$& .2 3 c&annels

normal network: IU network:

reuse 12 reuse 12 in regular la"er 24 c&annels

reuse in su#er la"er 12 c&annels

!"R#s/cell $ regular % $ super"R#s/cell & ' "R#/cell

Capacity gain of aout /!


Regular / Super Reuse Layer(Capacity *ain)

4ig$ CA=> .eglar @ s#er rese layer (ca#acity gain)

7$2$2$2 &acro and &icro Cell Networ.

The IUO conce#t can !e a##lied also to networks having a macro andmicro cell layer$ *hile the macro cells have to !e ei##ed !oth withreglar and s#er rese T.Bs as sal& the micro cells may !eei##ed with s#er rese T.Bs only$ /ch a micro cell is called a childcell& while the srronding ad"acent macro cells are called parentcells(see 4ig$ C A


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Regular / Super Reuse Layer(Macro an+ Micro Cell Network)

Macro Cells (,arent cells)

.eglar F s#er rese T.Bs

Micro Cells (C-il+ Cells)

7ay !e ei##ed with s#er rese T.Bs only AGcell,arred E N to avoid access dring call set #

acr cell area ser!e) *" regular 6R7

acr cell area ser!e) *" su#er reuse 6R7

'&il) cell

4ig$ CA .eglar @ /#er rese layer (macro and micro cell network)

7$2$: Intelligent 1re/uenc ;opping

IUO can !e a##lied simultaneouslwith freency ho##ing$ This iscalled intelligent freency ho##ing and im#roves frther the ca#acity ofthe network$

The two IUO layers ho# inde#endently from each other$ ,oth !ase !andand .4 ho##ing can !e sed$ It is not possi'le to perform 'oth .indsof hopping simultaneousl$

To s##ort an inde#endent freency ho##ing control for !oth IUOlayers& the following #arameters are sed for the nderlay network>

underla;opping&ode(U;!


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C A5& eam#les for !ase !and and .4 ho##ing are shown !y 4ig$ C ADand 4ig$ C AC$


Intelligent

Underla!"erla Intelligent .reuency 0opping(,arameters)

Intelligent Un+erlay 1erlay %.reuency 0opping

4reency ho##ing inde#endent for each layer,oth !ase !and and .4 ho##ing a##lica!le& !t not simltaneosly

Independent parameter settings for each laer

+egular laer ,uper reuse laer

!tsIs'o##ing nderlay'o##ing7ode ,,&.4&Nho##ing/eenceNm!er ho##ing/eenceNm!er ;$$D=sed7o!ilellocation nderlay7 ;$$255maioOffset nderlay7aioOffset ;$$D2

maio/te# nderlay7aio/te# ;$$D2

4ig$ CA5> Intelligent freency ho##ing (#arameters)



Intelligent .reuency 0opping(23ample for 4ase 4an+ 0opping)

"R#

"R# $

"R# !

5 6$ "imeslot

"R# '

4CC0

fr

fr$

fr!

fs

SN16i+esl$ 0 s !er 6R7s 2-3 nl"B'' )es n$ SN2

6i+esl$s 1- !er all 6R7s

"R# 7

"R# 8

fs$

fs!

SN6i+esl$s 0- !er all 6R7s

N B''

Regular6R7s

Su#er reuse 6R7s

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4ig$ CAD> Intelligent freency ho##ing (eam#le for !ase !and ho##ing)


IntelligentUnderla!"erla Intelligent .reuency 0opping(23ample for R. 0opping)

"R#

"R# $

"R# !

5 6$ "imeslot

"R# '

4CC0 fr1 8 n #ing

fr29 fr3... 8 #ing accr)ing A lis$

"R# 7

"R# 8

fs19fs2... 8 #ing accr)ingA lis$N B''

Regular6R7s

Su#er reuse 6R7s

4ig$ CAC> Intelligent freency ho##ing (eam#le for .4 ho##ing)

7$: TC; *llocation

7$:$% Call ,et Up

In a call set #& a T6' is allocated from a reglar T.B$ If no T6' isavaila!le on sch a T.B& the reest will !e re"ected& even if there are

free resorces on s#er rese T.Bs$ If directed retry is ena!led& thanthe following #rocesses are #ossi!le>

Inter cell handover from the /66' of the serving cell to a T6' on a

reglar T.B of an ad"acent cell$ This kind of directed retry has !eendiscssed already in cha#ter H'andover 6ontrol and d"acencies&section Im#erative 'andovers$

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Intra or inter cell handover from the /66' of the serving cell to a

T6' on a s#er rese T.B of the serving or a child cell$ This kind ofdirected retry is discssed now$

7$:$2 ?irected +etr to ,uper +euse T+

,oth kinds of directed retry mst !e ena!led individally$ s discssedalready& directed retry to a reglar T.B is ena!led !y setting the#arameter drinUse to 8$ irected retry to a s#er rese T.B isactivated !y the #arameter enaTch*ss,uperIU!(6T*)(;!C)(3$$:2)(3)$If it is set to a vale G ;& it indicates the time in /66' #eriods (from theT6' assignment reest)& dring which target cell evalation and thsdirected retry is not allowed$ /o this #arameter corres#onds to the timerminTime-imit?irected+etrsed for directed retry to a reglar T.B$ If

enaTchss/#erIUO is set to ;& directed retry to a s#er rese T.B isdisa!led$ The time dring which target cell evalation is allowed& iscontrolled !y the same #arameter ma0Time-imit?irected+etras fordirected retry to a reglar T.B$ The #arameters are smmari?ed !y 4ig$C AJ$



9irecte+ Retry(,arameters)

Call SetUp

T6' allocation to reglar T.B onlyNo resorces AG . to s#er rese T.B of serving or child cell or. to reglar T.B of ad"acent cell


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only& if 6@I is good enogh$ Ths it is a s#ecial case of IUO s#ecifichandover$ The estimation of 6@I and the target cell selection for IUOs#ecific handover are discssed later in this cha#ter$

If !oth kinds of directed retry are #ossi!le& that to a s#er rese T.B hashigher #riority$ If directed retry to a s#er rese T.B is not #ossi!le& the,/6 tries directed retry to a reglar T.B$ If this fails also& the call set #finally is cleared$ The #ractical handling of directed retry is de#icted !y4ig$ C AK$


Regular "R#

ueue (S9CC0)

C/I ratio goo+ enoug-;


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from a s#er layer to reglar layer $

handover attem#t to a reglar T.B can !e either an intra ,/6 (intercell or intra cell) or inter ,/6 handover$ The sorce T.B can !e either areglar or s#er rese T.B& the latter either in a #arent or child cell$ If noT6' is availa!le on the target& the handover reest is re"ected& even ifthere are still free resorces on s#er rese T.Bs (see 4ig$ C A1;)$

NOKIA BSSPAR/ 10.05.2004


Con1entional 0an+o1er(1er1iew)

0an+o1er to regular "R#Inter or intra ,/6Inter or intra cell4rom reglar or s#er rese T.B4rom #arent or child cell

O reques$ $ regular 6R7

T6' on reglarT.B availa!le L

No

'andover failre even if thereare free s#er rese T.Bs

es

'andoversccessfl

4ig$ CA1;> 'andover (overview)

7$# &easurement


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rese layer$ Therefore it is essential to measre the downlink receivelevel of the serving& reglar ad"acent and interfering cells$

7$#$% *"eraging

*ithin an IUO network& the measrement re#orts sent !y the 7/ are#rocessed !y the same way as within an ordinary one& i$e$ first these areaveraged !y the ,T/ (if desired) and afterwards !y the ,/6$ 4or thereceive level data of the interfering cells& the si?e of the ,/6 averagingwindow is controlled !y the #arameter intfCell*"gWindow,i@e(,IA6)(;!C)(%$$:2)(%3) which gives the nm!er of measrements #reA#rocessed !y the ,T/ as sal$ The maimm nm!er of ?ero resltswhich can !e ignored for the average #rocess& is set !y the #arameterintfCellN'r!fAero+esults(A6+!)(;!C)(3$$:%)(2)$

7/ s#eed detection can !e #erformed within an IUO network as well$ Ifthe 7/ is considered as a fast moving one& the #arameters controllingthe averaging of the interfering cell data can !e scaled as sal$ Theaveraging #arameters are smmari?ed !y4ig$ C A11$

7$#$2 oo. eeping

4or each s#er rese T.B (or s#er rese freency gro#) # to 1;interfering cells can !e defined$ 4or each call& the ,/6 can maintain #to =2 interfering cells$ /o the ,/6 is a!le to monitor several s#er rese

T.Bs simltaneosly$

n interfering cell can !e measred !y the 7/ only& if it is ad"acent tothe serving cell$ 4rthermore& the measrement re#ort incldes only thesi strongest ad"acent cells$ s interfering cells are often weak& sallythey are not indicated in every measrement re#ort& i$e$ a lot of ?eroreslts are o!tained$ ,ook kee#ing is smmari?ed !y 4ig$ C A11$

1


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Measurement ,rocessing(=1eraging)

C/I ratio key oser1ale of IU network ; 7easrement 0rocessing (averaging)

7$#$: CI 6stimation

The averaged receive levels of the interfering cells now are com#aredwith the receive level of the serving cell to determine the 6@I ratio$ Thereare two methods which can !e selected !y the #arametersuper+euse6st&ethod (&6T;)(;!C)(*B6=&*=IC6=N!N6)(N!N6)$If it is set to 3-& the a"eraging ta.ingmethod is sed& i$e$ the receivelevels of the interfering cells are averaged$ One can give each interferingcell an individal weight !y the #arameter ci6stWeight (W%>W5)(*?C)(3$$%3)(%)$ 6ells with weight ; are eclded from the calclation$ Ifs#er.ese-st7ethod is set to 7B& the ma0imum ta.ingmethod isa##lied& i$e$ the receive level of the strongest interfering cell is ado#ted

to !e the overall interference level$ If the #arameter is set to I6-& insteadof the IUO the for intelligent coverage enhancement (I6-) is switchedon$ This will !e discssed in cha#ter H6overage -nhancement 4eatres$*ith the setting NON- !oth IUO and I6- is disa!led$

The 6@I ratio is estimated not only for the serving cell& !t also for thead"acent child cells$ This is essential es#ecially for handover attem#ts$

One can average over all detected interfering cells& or only over thoseindicated among the D strongest ad"acent cells !y the last measrementreslt$ This is controlled !y sing the #arameter allInterfCell*"eraged



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(*B6+) (;!C)(8N)(N)$ If all detected interfering cells shall !econsidered& the #arameter mst !e set to8$

If the receive level of an interfering cell cannot !e measred directly& it

can !e estimated !y measrements of ad"acent cells which have asimilar .4 #rofile$ If the relation !etween the level of the interfering andthe measred cell is known in d, e$g$ !y test measrements& thisinformation can !e sed !y setting the #arameter le"el*dustment (-%>-5)(*?C)(>4:$$4:)(3)$ Then the ad"acent cell is sed as referencecellre#resenting the tre interference sorce$ To indicate a cell as areference one& the #arameter ci6stimationTpe (T%>T%3)(T+)(3=%)(3)mst !e set to %$ The vale ; indicates a cell which is a tre interferencesorce& i$e$ with directly measred receive level$ The 6@I estimation#arameters are smmari?ed !y 4ig$ C A12$ /everal cells can !e sed toestimate the 6@I level generated !y the interfering cell$ These referencecells can have different weights$



Measurement ,rocessing(C/I 2stimation)

2stimation met-o+

s#er.ese-st7ethod 3-&7B&I6-&NON- 3-> the receive level averaged over allinterfering cells is taken7B> the receive level of the strongestinterfering cell is taken

ci-st*eight ;$$1; weight of interfering cell& if average method issed

allInterf6ellveraged &N > The average method is a##lied to allknown interfering cellsN> The average method is a##lied only tointerfering cells indicated !y the last

measrement re#ort

+eference cells

6ells which are not tre interference sorces& !t have a similar signal #rofile as the serving cell

leveld"stment AD=$$D= d, ratio signal level @ interference level ado#tedfor reference cell

ci-stimationTy#e ;&1 ;> interference level of ad"acent cell measreddirectly1> ad"acent cell is reference cell

4ig$ CA12> 7easrement #rocessing (6@I estimation)

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7$5 IU! ,pecific ;ando"er

7$5$% Introduction

7$5$%$% IU! ,pecific ;ando"er Tpes

The main #r#ose of IUO is to increase the network ca#acity !y addinga layer with tight freency rese$ The ,/6 #ts and kee#s a 7/ in thislayer& if ever #ossi!le$ There are three kinds of handovers to achieve thisaim>

irected retry> ring call set #& the initial T6' mst !e from a

reglar T.B$ If sch one is not availa!le& directed retry is a##lied$ If

the 6@I ratio will !e good enogh& as target a s#er rese T.B istaken$ This has !een discssed already in section C$=$2$

IUO handover> ring an ongoing call& the ,/6 tries to handover the

7/ to a s#er rese T.B& if the 6@I ratio will !e good enogh$ Thiswill !e discssed in the following$

irect access #rocedre> If the received level will eceed a certain

threshold& the ,/6 tries handover to a s#er rese T.B withotchecking the 6@I ratio$ This will !e discssed in the following also$

Of corse handover can take #lace also !ecase one of the manyconventional reasons$ The rles which this handovers have to follow in

an IUO network& have !een discssed already in section C$=$=$

7$5$%$2 Triggering

+ike conventional handover& IUO handover is !ased on a continosmonitoring of measrement vales& es#ecially of the receive levels of theserving cell and the ad"acent reglar and interfering cells$ s shown insection C$%27$$%27)(%3)$ If at least


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rese T.Bs of the serving cell !elonging to another freency gro#than the serving T.B& and for the ad"acent child cells& the ,/6contines to com#are the 6@I ratio with s#er.ese8ood6iThreshold$

If the receive level for a s#er rese T.B is very high& a good 6@I ratio isgaranteed anyhow$ /ch a T.B can !e sed as handover targetimmediately& withot checking for the 6@I ratio$ This is controlled !y the#arameter direct*ccess-e"el (?*-)(T+)(>%39$$>#7=N)(N)$ 4or thecom#arison with this threshold only the lastaveraged receive level valeis considered& instead of a sam#le of N ones$ The nit of the #arameteris d,m$ If it is set to N& direct access is disa!led$ Triggering issmmari?ed !y4ig$ C A1=$


IU Specific 0an+o1er("riggering)

t-res-ol+

=ctual a1erage samples

N3samplesLess t-an ,3samples e3cee+ C/I t-res-ol+No IU -an+o1er triggere+

N3samples,3samples e3cee+ C/I t-res-ol+IU -an+o1er triggere+C/I ratio t-res-ol+s (IU -an+o1er)

s#er.ese8ood6iThreshold -12..12 )Bs#er.ese,ad6iThreshold -12..12 )B

Num'er of a"erage samplesN 1$$=20 1$$=2

Recei1e le1el t-res-ol+s (+irect access)directccess+evel A1;K$$A


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If a handover to a s#er rese T.B fails& a frther attem#t is not allowed&ntil minIntUnsuccIuo;o (&I!)(;!C)(3$$255)(23) (the nit is s)e#ires$ If the 6@I ratio !ecomes too !ad& a handover to a s#er reseT.B of the same freency gro# is not allowed dring

minIntIuo;o+e/E (&I+)(;!C)(3$$255)(%3)$ gain the nit is s$ Thetimers are smmari?ed !y 4ig$ C A1


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7$5$2$2 IU! ;ando"er

This is the key fnctionality of IUO$ There are two cases& for which thereali?ation is somewhat different> 'andover to a s#er rese T.B andhandover from a s#er rese T.B$ ,oth are !ased on the monitoring ofthe 6@I ratio for the s#er rese T.Bs of the serving cell and ad"acentchild cells$ IUO handover always is an intra ,Chandover$

;ando"er from a +egular to a ,uper +euse T+

This handover is triggered& if a s#er rese T.B offering a sfficient 6@Iratio is detected$ If !oth a good ad"acent child cell and a serving s#errese T.B are availa!le& the child cell has higher #riority$

If the criteria for .. handover or other handover for other reasons areflfilled these handover have a higher #riority than the 8ood 6@I

handover$ The handover #rocess is smmari?ed !y 4ig$ C A15& anmerical eam#le is given !y 4ig$ C A1D$



IU 0an+o1er(Regular "R# ;< Super Reuse "R#)

Su#er reuse 6R7 ,i$&

A; '/I ra$i s#er.ese8ood6iThreshold

6hild cellsavaila!le L

Noes

Inter cell handoverto cell with !est 6@I

Intra cell handoverto T.B with !est 6@I

4ig$ CA15> IUO handover (reglar T.B AG s#er rese T.B)

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Regular freuencyf'

Super reuse freuencyf

Regular freuencyf?

IN"2R.2R2NC2


IU 0an+o1er(Measurement 23ample)

Super reuse freuencyf@

f4 -105)B+

f1 -105)B+

f: -


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NOKIA BSSPAR/ 10.05.2004


IU 0an+o1er(.rom Super Reuse "R#)

A; '/I ra$i s#er.ese,ad6iThreshold

I/

'andover toreglar T.B

ena!leInter4rtIo'o

/U0 and !ad 6@I

,etter s#er resefre(ency gro#savaila!le L

Noes

'andover to it 'andover toreglar T.B

/U0 and other handover trigger or .-8

.eglar T.Bavaila!le L

Noes

'andover to it 'andover to s#errese fre(encygro#

4ig$ CA1C> IUO handover (from s#er rese T.B)

'andover from the s#er rese layer !ack to the reglar layer is either aintra cell handover or an inter cell handover from a child to an ad"acent#arent cell$

'andover from a s#er rese T.B to another one is either a intra cellhandover or an inter cell handover from a #arent or child cell to anad"acent child cell$ Inter cell handover to an ad"acent #arent cell is notallowed$ In case of intra cell handover one mst distingish frther!etween intra and inter s#er rese freency gro# handover$ Intrafreency gro# handover can !e triggered only !y interference andmst !e ena!led !y setting the #arameter ena'leIntra;oInterU-?-(6IC6I;)(;!C)(8N)(8) to 8$ If this handover fails& the ,/6 may try ahandover !ack to a reglar T.B$ The different handover ty#es aresmmari?ed !y4ig$ C A1J$

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Su#er 3

in$er-cell Paren$ >'&il) Su#er >Su#er 4

in$er-cell '&il) >'&il) Su#er >Su#er 5

in$er-cell '&il) >Paren$ Su#er>Regular


IU 0an+o1er(0an+o1er "ypes)

4ig$ CA1J> IUO handover (handover ty#es)

7$5$2$: ?irect *ccess

If the receive level is very high& a s#er rese T.B can !e accessedimmediately& withot checking for the 6@I ratio$ This may !e donealready dring call set #& or dring an ongoing call$

?irect *ccess during Call ,et Up

This is either an intra cell handover& from the reglar /66' to a s#errese T.B of the serving cell& or an inter cell handover from the reglar/66' to a s#er rese T.B of an ad"acent child cell$ The handover isallowed only& if !oth the #link and downlink signal ality on the/66' and the 7/ distance to the ,T/ do not eceed a handoverthreshold$

If there are several #ossi!le targets& in case of an intra cell handover theT.B with the highest receive level threshold is sed$ In case of an intercell handover the #ossi!le child cells are ranked like for a conventionalhandover& and the cell with highest rank is sed$ The whole #rocess issmmari?ed !y 4ig$ C A1K$

Nokia Networks Oy 2=(25)


24/25




9irect =ccess(9uring Call Set Up)

Su#er reuse 6R7 ,i$&

CurrentA; R@ le!el directccess+evel

6hild cellsavaila!le L

Noes

6onventional ranking

Inter cell handover tocell with highest rank

.anking according directccess+eve

Intra cell handover to s#er rese T.Bwith highest directccess+eve

4ig$ CA1K> irect access (dring call set #)

?irect *ccess during an !ngoing Call

This always is an inter cell handover& either from a reglar T.B to as#er rese T.B& or from a child cell to a #arent cell$ It is allowed onlyfor trn arond corner& fast @ slow moving 7/& #ower !dget andm!rella handover& i$e$ it is a conventional handover if the,uper+esuse 6st&ethod is set on for the target cell$ If the downlinkreceive level of the current T.B or the signal ality eceeds ahandover threshold& the corres#onding handovers are #erformed insteadof the direct access$

The #otential targets are ranked according the conventional scheme$ Ifthe target of highest rank does not have a s#er rese T.B& directaccess is not #ossi!le$

2


25/25




9irect =ccess(9uring ngoing Call)

Su#er reuse 6R7 ,i$& CurrentA; R@ le!el directccess+evel and$urn arun) crner handover triggered orfast @ slow moving 7/ or#ower !dget handover triggered orm!rella handover triggered

es

6onventionalhandover

,ad #link or downlink ality ortoo low downlink .B level L

No

6onventional ranking6ell with highest rank has s#er rese T.B L

Noes

Inter cellhandover

'andover not #ossi!le

4ig$ CA2;> irect access (dring ongoing call)

bsspar chapter 07 intelligent underlay overlay mo

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