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Agenda Item: 23.20

Tt!e: GS" and #"TS $e!!% n the %ame &o'tng a&ea

ate 19-APR-1999 (0.1)

So'&$e *oka

Re!ated To Amendment to #"TS "" %e$ton o+ 23.20

1. INTRODUCTION

The o%%!t to ha/e GS" and #"TS $e!!% n the %ame &o'tng a&ea % $'&&ent! n$!'ded n 23.20.oe/e&, the&e a&e 'n%o!/ed te$hn$a! &o!em% th th% $on$et. The%e a%e$t% a&e de%$&ed n th%$ont&'ton.

2. GENERAL

The neto&k $on+g'&aton n g'&e 1 ha% een &oo%ed n %tanda&d%aton. Th% a&oa$h $o&&e%ond% to andea o+ %$atte&ng 3G $e!!% among 2G $e!!% one--one. The&e+o&e, the 3G $e!!% o'!d not &o/de an

%gn+$ant $ontn'o'% $o/e&age, h$h mean% that an 3G $onne$ton m'%t a!a% e &ea&ed to +a!! a$k to2G ('%t !ke an S4S $onne$ton ma !oo%e t% hgh %eed $aa!te% n a hando/e& - e$a'%e o+ d++e&ent&ea%on%, tho'gh). Th% o'!d make the 3G %e&/$e% a ho%tage o+ &e%ent 2G $aa!te%, e%e$a!! hen a$ket %e&/$e % $on%de&ed. A% a &e%'!t, 3G '%e&% !! ha/e mnma! + an $on+den$e on a/a!a!t o+ 3G$aa!te%. The&e+o&e, ha/ng 3G $e!!% m5ed n the mdd!e o+ GS" $e!!% o++e& !tt!e ad/antage and doe% not%eem a&o&ate.

 

 A/Gb-interface   Iu-interface

RA

ove

CN

BSS UTRAN

GSM ce  UMTS ce

g'&e 1

An a!te&nat/e +o& the ao/e %$ena&o % !!'%t&ated e!o g'&e 2. In th% $a%e, the GS" and #"TS $e!!% e!ong to d++e&ent 6A7RA. A% a &e%'!t, n d!e mode the #87"S ha% to e&+o&m 6A7RA 'date hen $&o%%ngthe o&de& eteen GS" and #"TS. The ene+t% o& &atona!e +o& th% a&oa$h % de%$&ed e!o.

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 A/Gb-interface   Iu-interface

RA!

CN

BSS UTRAN

RA&

g'&e 2

The '&o%e o+ th% $ont&'ton % to %ho that a!te&nat/e de%$&ed n g'&e 1 % te$hn$a!! an 'na$$eta!eoton.

3. TECHNICAL ASPECTS TO BE CONSIDERED

3.1 Paging vs. Location u!ating "oa!

In $a%e o+ $ommon &o'tng a&ea +o& GS" and #"TS $e!!%, the don%e % %'otma! '%age o+ agng

$hanne! a% the #8 % a%%'med to e !%tenng on! to one %%tem at a tme. A% a &e%'!t, the agng /a the othe&%%tem the #87"S % not !%tenng to % a!a% e&+o&med n /an.

Conclusion: No optimization benefits foreseen.

3.2 Routing a#$a u!at$ #oc$!u#$

A &o$ed'&e %ho'!d e e&+o&med hen mo/ng eteen #"TS and GS" n o&de& to &enegotate the %e&/$e

a$$o&dng to the ne $aa!t o+ the %%tem. It %ho'!d a!%o e o%%!e to e&+o&m %e$'&t $he$k a% d'&ng a$hange eteen #"TS and GS" the a&e not e&+o&med the &ado. The e5%tng Ro'tng A&ea &o$ed'&e %$o/e&ng the%e to a%e$t%. The&e+o&e t %ho'!d e e&+o&med &ega&d!e%% + the RA &ead n the %%tem n+o %$hanged o& not hen mo/ng eteen #"TS and GS". The &ea%on +o& '%ng RA 'date n%tead o+ a neme%%age % to &ed'$e the ma$t on the e5%tng GPRS %%tem and a/od 'nne$e%%a& o&k.

When the Ro'tng a&ea &o$ed'&e % '%ed 'on #"TS-GS" $hange%, t % &a$t$a! to ha/e #"TS and GS"$e!! n d++e&ent Ro'tng a&ea n o&de& to:

- otm%e the agng

- ha/e a nat'&a! t&gge& o+ the Ro'tng A&ea 'date &o$ed'&e

3.3 S$cu#it%

The d'a! mode #8 ma ant to %ta&t neto&k a'thent$aton, on$e a 3G $e!! % %e!e$ted. A!%o, the SGS* maant to e&+o&m #"TS a'thent$aton a+te& the "S ha% made a$$e%% /a 3G. The %ame a!e% +o& $he&ng.In o&de& to ha/e #"TS %e$'&t at hand, the&e ha% to e #"TS $he&ng ke% a/a!a!e. o& e5am!e, + theRA a% made /a GS" $e!!, then on! GS" %e$'&t o'!d e a/a!a!e n 3G $e!!, th'% &e%'!tng n that on!GS" %e$'&t o'!d e a/a!a!e. To a/od that, t % ne$e%%a& to e&+o&m #"TS a'thent$aton on$e the 3G$e!! % $ho%en.

Conclusion: Putting 2G and 3G cells into same RA/LA ill result in !in practice" t#at t#e $%&' can onl( offer 

2G securit( in suc# an area. &o support $%&' securit() approapriate update is needed.

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3.& GS' on"% su(sc#i($# 

I+ the $e!!% e!ong to the %ame RA, the&e % a &o!em on nhtng (ant$ated) GS" on! %'%$&e&% to$am n 3G, e%e$a!! hen the&e % a GS" SI" n/o!/ed. o& e5am!e, n the $a%e o+ "T $onne$ton, the#8 o'!d &e$e/e agng /a 3G, 't then the a$$e%% o'!d e dened /a the %e&/ng $e!!. I+ the te&mna! hadon! %taed n GS", t o'!d ha/e &e$e/ed the %e&/$e mmedate! tho't an dena!%.

Conclusion: RA update is needed for !idle mode" access control.

3.) S$#vic$ not suo#t$! in GS'

The d&/e& +o& nt&od'$ng 3G % not to get a ne and +o& the %ame %e&/$e%, 't to nt&od'$e ne %e&/$e%.The&e+o&e, gong to GS", mean% !oo%ng g& o+ %'$h ne %e&/$e%. In d!e mode, e&+o&mng an a&o&ate"" 'date % the a to nd$ate to the 4* that the te&mna! % no !onge& %e&/ed an #"TS $e!!.

Conclusion: %% le*el update #en going from 3G to 2G is ala(s needed for ser*ice discrimation !idle mode

C%".

3.* T$#+ina" 2G vs. 3G caa(i"iti$s

o& e5am!e, t % o%%!e that the&e a&e te&mna!% ha/ng oth 4S and PS $aa!te% n 3G 't on! 4S n2G. The $a%e o+ ha/ng 2G and 3G $e!!% n the %ame RA &e%'!t% n that hen the "S7#8 % e&+o&mng 'date

t ha% to take nto a$$o'nt the $aa!te% n the othe& mode. In GPRS, the GPRS neto&k mode o+ oe&aton % &oad$a%t n a!! the RA n o&de& to n+o&m the "S on the agng hand!ng n the RA. The "S then e&+o&m%atta$h &o$ed'&e(%) a$$o&dng to t% $aa!t.

I+ #"TS and GPRS $e!!% a&e n the %ame RA, th% GPRS a&amete& %ho'!d e &oad$a%t n #"TS $e!! a% e!!.

Th% o'!d !mt the "S to t% GPRS $aa!te%, a% t % o%%!e that the&e a&e te&mna!% ha/ng oth 4S andPS $aa!te% n 3G 't on! 4S n 2G, +o& e5am!e.

Conclusion: &o +eep it simple t#e G'% and $%&' cells #a*e to belong to different RA!/LA".

&. CONCLUSION

The&e a&e no &ea! ene+t% o+ ha/ng oth GS" and #"TS $e!!% $onne$ted to %ame RA. The ene+t o+mnmng RA(76A) 'datng %gna!ng !oad % dmn't/e $oma&ed to the d%ad/antage% and added$om!e5t hen $oma&ed to the a&oa$h o+ ha/ng $e!!% e!ongng to d++e&ent RA(76A).

). PROPOSAL

It % &oo%ed that the te5t n 23.20 /.1..0 $hate& ;.3.10 Re