Toi Uu Vung Phu 7545
Transcript of Toi Uu Vung Phu 7545
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TRN QUANG HUY3G DEPT Vietteltelecom
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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