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TRN QUANG HUY3G DEPT Vietteltelecom

huytq@viettel.com.vn0983998282

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NI DUNG TRNH BY

Ti u vng ph (Coverage)

Tiu chun v RSCP v Ec/No m bo vng ph tti vi tng vng (DU, U, SU, RU).

Cch ti u vng ph theo RSCP v Ec/No. Cc bc thit lp bi o vng ph trong ch Idle.

Kim tra vic chn li cell ( Cell Reselection)

Kim tra cp nht v tr (LAU, RAU)

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I. Ti u vng ph:

1. Tiu chun vng ph tt:

RSCP: Receive signal code power

Ec/No: Energy per chip over total received power

spectral density Target ca RSCP v Ec/No i vi vng ph cho

dch v thoi (voice call v video call):

RSCP -105dBm trn 95% mu o

Ec/No -12dB trn 95% mu o

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Vi thc t suy hao gia Indoor v outdoor cho tng

vng nh sau:

Do tin hnh Driving Test khng s dng Antenngoi nn Target cn t c i vi tng vngnh sau (yu cu trn 95% mu o):

Area Densurban Urban Suburban Rural CarPenetration Loss(Outdoor/Indoor)

25dB 20dB 15dB 8dB 8dB

Area Densurban Urban Suburban RuralRSCP (dBm) -88 -93 -98 -105

Ec/No (dB) -12 -12 -12 -12

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GOOD COVERAGE

NO DOMINANT PILOT

POOR COVERAGE

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I. Ti u vng ph (tip):

2. Cch ti u vng ph:

Nguyn nhn RSCP thp:

Do che chn ca cc ta nh cao tng, cng trnh ,

Tilt ca anten ngng qu hoc cp qu. Sai Azimuth hoc sai loi anten.

H thng feeder anten b suy hao qu ln.

t sai cng sut knh CPICH Li phn cng NodeB

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Cch khc phc RSCP thp: iu chnh Azimuth

iu chnh Tilt

Thay loi anten ph hp

Kim tra li cng sut knh CPICH

Kim tra cc cnh bo ca NodeB

Kim tra cc u ni ti NodeB

o VSWR, kim tra feerder anten v cc u connectors

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Nguyn nhn Ec/No thp:

Pilot Pollution: c qu nhiu knh Pilot c RSCP tt ticng 1 v tr (vng ph chng ln nhiu).

Thiu Neighbour 3G, 1 cell mnh m khng c nh

ngha neighbour s tr thnh nhiu lm gim Ec/No. Vng ph km RSCP thp dn n Ec/No thp.

Cell selection/reselection chm hoc khng thc hinc dn n UE Camped on vo cell ti.

Ti ca cell cao cng dn n Ec/No thp.

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Cch khc phc Ec/No thp:

Gim Pilot Pollution: chn 1 cell tt nht lm serving,gim vng ph cc cell khc nhm gim chng ln(bng cch chnh Tilt, azimuth,)

Kim tra Neighbour 3G, nu thiu th khai thm. Nu Ec/No thp do RSCP yu l do vng ph km, x

l tng RSCP (bc trn).

Kim tra vic chn li cell (bc sau)

Trong trng hp ti ca cell cao => tm cch share ti.

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I. Ti u vng ph (tip):

3. Thit lp bi o:

Chun b b o gm: my tnh, MS, GPS,Dongle/License, xe t.

Kt ni my tnh vi b o, t ch Idle cho tontrnh o.

Lu li Log file, tn log file th hin cc thng tinngn gn, d gi nh ( theo ngy thng nm, aim o).

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Chn Route o: yu cu lp sn route t nh, phibo m route o chy qua bin ca tt c cc cellcn o.

Chiu di chuyn phi thng nht gia cc ln o.

Thi gian o: ti thiu l 1.5 ting cho mi clustergm 5 trm (15 cells).

Tc di chuyn: ty tng khu vc m tc dichuyn khc nhau (khu vc trm dy th di chuynchm, trm tha c th di chuyn nhanh hn nhng

ti a l 50km/h), phi bo m di chuyn u(khng c lc nhanh lc chm).

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II. La chn li cell (Cell Reselection):

1. Nhn bit: Cell serving suy yu (RSCP v Ec/No gim), ng

thi xut hin t nht 1 cell khc mnh hn (RSCPv Ec/No ln hn) nhng khng xy ra chn li cell

Khi cell serving suy yu hoc mt sng, UE campedon vo cell khc mnh hn rt nhiu => Reselectionchm hoc khng thc hin c.

2. Nguyn nhn:

Khai thiu neighbour, thiu hoc sai Outer Cell/LAI. Tham s la chn li cell t qu su.

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3. Khc phc:

Kim tra li khai bo Neighbour, Outer Cell/LAI. Kim tra tham s khai bo cho Cell Reselection trong

bn tin SIB3/SIB4, nu khai qu su th t li

Cc tham s khai cho Cell Reselection hin th trong bntin SIB3/SIB4 gm:

q-QualMin: mc yu cu ti thiu v cht lng cacell (Ec/No q-QualMin).

q-RxlevMin: mc yu cu ti thiu v mc thu ca cell(RSCP q-RxlevMin.

t-Reselection-S: thi gian chn li cell, nu t qu lus dn n Cell Reselection chm.

q-Hyst-l-S, q-Hyst-2-S: tr reselection ng vi RSCP,Ec/No.

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q-Offset-l-S,N; q-Offset-2-S,N: offset gia Serving

v Neighbour ng vi RSCP, Ec/No. Gi tr:

Parameter Allowed Range Recommended

q-QualMin (dB) -24 n 0 -16

q-RxlevMin (dBm) -115 n -25 (step 2) -113

t-Reselection-S (s) 0 n 31 1

q-Hyst-l-S (dB) 0 n 40 (step 2) 2

q-Hyst-2-S (dB) 0 n 40 (step 2) Defaults to q-Hyst-l-S

q-Offset-l-S,N (dB) -50 n 50 1 (cng site), 3 (khc site)

q-Offset-2-S,N (dB) -50 n 50 1 (cng site), 3 (khc site)

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III. Cp nht v tr (LAU, RAU): Khi tin hnh o, nu xy ra vic cp nht v tr

(LAU, RAU) th yu cu phi thnh cng 100%.

Nu xut hin LAU hoc RAU tht bi, yu cu htr t phng TKT khu vc kim tra v khcphc li.

Nguyn nhn: do khai bo LAC, RAC trn MSC vSGSN sai.

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NI DUNG CNG VIC CN LM:

1. Thit lp bi o trong ch Idle, o theo Route lp sn.

2. Trong qu trnh o, theo di v pht hin vng sngyu (RSCP thp) v vng Pilot Pollution (chng ln

nhiu, RSCP cao nhng Ec/No thp) => a binphp x l.

3. Trong qu trnh o, theo di vic la chn li cell,nu pht hin khng chn li c hoc chn li

chm => bin php x l.4. Trong qu trnh o, theo di qu trnh LAUv RAU,

nu pht hin False => bin php x l.

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THANK YOU