Tai lieu huong dan Drive Test.pdf

Ti liu hng dn Drive Test TEMS

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TNG QUAN GSM Trc tin cng im qua v cc nh ngha c bn trong GSM:

1. Cu trc mng GSM

1.1. Trm di ng (MS)

Trm di ng l giao din gia ngi s dng v mng, c cu thnh bi hai phn ring bit:

- Thit b hoc u cui di ng. - Module nhn dng thu bao (SIM)

1.2. Trm thu pht c s (BTS)

BTS hot ng nh l mt giao din gia MS v mng bng cch cung cp sng v tuyn t anten ph cho mt khu vc nht nh.

Chuyn ha cc tn hiu v tuyn GSM sang nh dng m BSC c th nhn. M ha khi s dng kha ciphering. M ha knh v chn. iu ch v gii iu ch. Ghi v chuyn n BSC cng tn hiu MS o c.


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1.3. Trm iu khin c s (BSC) BSC l nt trung tm trong mt BSS v c chc nng phi hp cc trm c s.

BSC iu khin mt phn quan trng trong mng v tuyn. Tnh ton vic chuyn giao. Tnh ton vic iu khin cng sut. Gim st mng truyn dn v hot ng ca tng BTS.

1.4. Trung tm chuyn mch (MSC) Thnh phn quan trng nht trong mng GSM l MSC. MSC iu khin cc cuc gi i v n ca cc MS. Cc chc nng chnh ca MSC bao gm:

Chuyn mch v nh tuyn cc cuc gi n hoc i ca MS. Tnh ph. Cung cp dch v. iu khin kt ni cc BSC. Truy cp trc tip cc dch v internet.

1.5. Trung tm chuyn mch cc dch v di ng Gateway (GMSC)

Gateway l mt node lin kt hai mng vi nhau. GMSC l giao din gia mng t ong di ng v PSTN. N c nhim v nh

tuyn cc cuc gi t cc mng c nh n ngi s dng GSM. GMSC thng c cng chc nng nh MSC.

1.6. B ghi nh v thng tr (HLR)

HLR l mt c s d liu mng tp trung cha v qun l cc ng k di ng thuc v mt nh mng c th.

HLR hot ng nh mt ni lu tr thng trc cc thng tin thu bao di ng cho n khi b hy.

1.7. B ghi nh v tm tr (VLR) Vai tr ca VLR trong GSM hot ng nh mt ni lu tr tm thi thng tin

thu bao cho MS ang trong khu vc ca mt MSC c th. Do s c mt VLR cho mi MSC v MSC s khng phi lin h vi HLR mi

khi thu bo s dng dch v hoc thay i trng thi. VLR lun c tch hp vi MSC.


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1.8. Trung tm nhn thc (AUC) B thanh ghi nhn thc c s dng cho mc ch bo mt, n cung cp cc thng s cn thit cho chc nng nhn thc. Cc thng s ny gip thm tra nhn dng ngi s dng.

1.9. B ghi nhn dng thit b (EIR) Do cc thu bao v thit b l ring bit trong GSM nn cn thit phi c mt qu

trnh xc thc ring bit cho tng thit b MS. Cc th tc nhn din thit b s dng chnh nhn dng IMEI ca cc thit b

m bo cc thit b u cui MS l hp l.

1.10. Trung tm vn hnh v bo dng (OMC) OMC c kt ni vi tt c cc thit b trong SS ( GMSC, cc MSC, HLR, VLR,

AUC, EIR v BSC). OMC c xem nh mt trung tm gim st m cc nhn vin c th theo di v

kim sot mng t xa.

2. Cu trc cc knh Logic ca h thng GSM

2.1. Knh lu lng Traffic Channels

Mang tn hiu thoi c m ha hoc d liu ngi dng trao i ln xung gia mt thit b di ng vi mt BTS.


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C hai loi knh lu lng vi tc truyn khc nhau l:

TCH/F: mt knh s chim 1 timeslot ca khung TDMA. Tc l 13kb/s cho thoi v 9.6kb/s cho data.

TCH/H: 2 knh s chim 1 TS nn tc gim i mt na nhng s lng 1 cell c th phc v li tng ln.

2.2. Knh bo hiu Control Channels

Nhm knh ny m bo cho cc bo hiu ca h thng nh: ng b, qung b, cp knh, thit lp cuc gi Chng c chia thnh ba nhm chnh nh sau:

Nhm knh qung b (BCH): L cc knh mt chiu theo ng xung, gm c: - FCCH: knh iu khin tn s gi ti MS, MS da vo hiu chnh tn s

pht. - SCH: knh ng b cho MS kh nng ng b vi trm BTS. - BCCH: gi cc thng tin c th v mng nh qun l ti nguyn v cc bn tin

iu khin. Nhm knh iu khin chung (CCCH): bao gm tt c cc knh ng xung ti

a im (mt BTS ti nhiu MS) v knh truy cp ngu nhin ng ln. - AGCH: c s dng n nh mt knh dnh ring (SDCCH) ti MS. - PCH: knh tm gi (pagging) gi tn hiu thng bo ti MS v mt cuc gi

n. - CBCH: l mt ty chn (c th c hoc khng) cho bn tin qung b SMS. - NCH: l mt ty chn (c th c hoc khng) dng cho dch v qung b

thoi. Nhm knh iu khin ring (DCCH): bao gm cc knh iu khin im im,

gm c hai hng (uplink/downlink). Cc nhm knh ny dng thit lp lin lc ring gia mt MS v h thng, qua h thng s lng nghe v thc hin cc yu cu hp l ca MS . - SDCCH: knh iu khin dnh ring c s dng cho thit lp cuc gi, LU

v SMS. - SACCH: knh iu khin lin kt chm c s dng cho bo co o v bo

hiu trong mt cuc gi. - FACCH: knh iu khin lin kt nhanh c s dng (khi cn) cho bo hiu

trong mt cuc gi, ch yu cho phn pht bn tin chuyn giao v cho hi bo khi TCH c gn.


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3. Cc loi trm BTS


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Gc ngng ca anten

Hng ca chm tia anten so vi phng thng ng. Gm ba loi nh hnh di:

Mt anten cu to gm c tilt c v tilt in:

Tilt c (M-Tilt): iu chnh bng cch thay i vt l bn ngoi anten. Tilt in (E-Tilt): iu chnh thay i b lng cc bn trong dn ti thay i

chm tia chnh.

Nn iu chnh M-Tilt hay E-Tilt ???

iu chnh M-Tilt c th gy ra nhiu do cc bp sng ngc tng v khng th iu chnh M-Tilt cho tng bng tn.

Ngc li c th iu chnh cho tng bng tn bng cch iu chnh E-Tilt m khng b nh hng can nhiu.


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V d: E-Tilt = 2

E- Tilt = 10


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4. Drive Test 4.1. Cc cng c cn chun b

1. Laptop 2. GPS 3. Phn mm TEMS 4. Dongle ( TEMS licence) 5. in thoi ( H tr TEMS) 6. Cp kt ni 7. Inverter

4.2. Cc thng s k thut 2G 4.2.1. GSM Serving + Neighbors

Cell name: Tn ca cell phc v v cell ln cn BSIC: M nhn dng trm gc

BSIC = NCC (m mng [0>7] + BCC (m trm [0>7]) ARFCN: Tn s v tuyn BCCH V d: Tn s 890.2 ---> ARFCN =1 Tn s 890.4 ---> ARFCN =2 RxLev: Mc thu tn hiu c o bi MS (dBm)


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4.2.2. GSM Current Channel

Time: Gi hin th trn my tnh Cell Name: Tn cell phc v ( hin th theo cellfile) CGI: m nhn din quc t

MCC: M quc gia MNC: M mng LAC: M vng CI: M cell

Cell GPRS support Band: bng tn. BCCH ARFCN: Tn s s dng cho c qung b v dch v. TCH ARFCN: Tn s s dng ring cho dch v. Mode: Idle/ Dedicated. BSIC: m nhn dng trm. Timeslot: knh cha TCH ca sng mang [0>7]. Channel type: TCH hoc BCCH. Channel mode: ch m ha knh (fullrate hoc halfrate).


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Channel codec: FR (fullrate), HR (halfrate), AMR (t l a thch nghi). Ciphering Algorithm: thut ton m ha. Sub channel number: SDCCH (c/khng ghi). Hopping Channel: c/khng cho mc cell. Hopping Frequencies: Tn s phn b trong cc nhm nhy tn. MAIO: Tn s m cuc gi bt u. Hopping Sequence Number: Trnh t m trong MS nhy tn trong cng TS.

4.2.3. Radio Parameter

RxLev: Mc thu tn hiu (-10 > -115) RxQual: Cht lng thoi (0 > 7) ph thuc vo BER ( t l li bit)


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FER: T l li khung BER actual: (s bit li/ s bite c truyn) SQI: ch s cht lng thoi

MS Power control level: iu khin cng sut (0 > 8) ph thuc vo thit k mng. DTX: Truyn khng lin tc. TA: Timing Advance (0 > 63).

4.2.4. GSM Hopping Channel

ARFCN RxLev C/I: T l nhiu trn sng mang.


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4.3. Cc thng s k thut 3G 4.3.1. WCDMA Serving/Active set + Neighbors

Type: SC Idle Mode, AS dedicated mode, MN Monitoring neighbor, DN Detected neighbor.

Cell Name: Tn cell (theo cellfile) SC: Scrambling Code UARFCN: Tn s s dng trong 3G CPICH Ec/No: t l nhn nng lng theo chip (Ec) trn nhiu (No) trong knh

pilot chnh.

CPICH RSCP: Mc thu knh pilot chnh


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4.3.2. HSPDA analysis

HS session: Active/No (Active khi c kt ni HSDPA) HS serving cell: SC ca cell phc v. CQI: Ch s cht lng knh

Lin quan gia CQI o bi UE, pilot Ec/Io v t l thng lng


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No: mc nhiu. Io: Nhiu do ting n (khng thc t) DSCH throughput: lu lng tnh bng kb/s.

4.3.3. Event


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4.3.4. Layer 3 messages Bao gm cc bn tin trao i ln xung gia MS v mng.


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4.4. Map

To bn dng Geosat

Ti bn dng Geosat

Ti Cellfile


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4.4.1. To Geosat map Theo cc bc t 1 n 9


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4.4.2. Ti Geosat map Theo cc bc t 10 n 12

Ngoi ra c th trc tip ti bn di nh dng .tab


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iu chnh cc lp hin th trn Map (Layer Control v Theme Setting)

Phn Layer Control la chn cc lp hin th (Visible).

Trong phn Theme Settings c th ty chn cc thng s hin th ca Coverage Layer,

Event Layer, Cell Layer theo mc ch.


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4.4.3. Ti Cellfile nh dng cell file

Configuration >>> General >>> Cell file load


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4.5. Cc bc thc hin trn TEMS 4.5.1. Kt ni thit b

Trc khi thit b kt ni. Thc hin thao tc kt ni tt c hoc kt ni tng thit b

Thit b kt ni thnh cng


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4.5.2. Ghi logfile


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4.5.3. c tnh thit b


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iu khin RAT (RAT control) Bnh thng

2G

3G


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iu khin bng tn (Band control) 900 900E 1800


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iu khin la chn cell GSM ( Idle mode control )

Kha cell theo BCCH ca cell cn kha


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iu khin chuyn giao GSM ( Dedicade mode control )


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iu khin chn cell WCDMA ( WCDMA cell selection control)


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4.5.4. Cch to sequence Control >>> Comand sequence >>> edit

iu chnh cc thit lp: thi gian cuc gi (call duration), khong cch gia hai cuc gi lin tip (wait), thit b (MS).


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5. Cc dng cng vic Drive Test 5.1. Cluster Bi o ny c thc hin kim tra kh nng truy nhp (Blocking) v kh nng duy tr (quality) ca h thng.

kim tra kh nng truy nhp: s dng bi o Short Call (vd: cuc gi 30s, khong cch gia hai cuc gi lin tip 10s)

kim tra kh nng duy tr: s dng bi o Long Call (vd: cuc gi 180s, khong cch gia hai cuc gi lin tip 10s)

V d cluster Marina


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5.2. Nghim thu cell mi 5.2.1. Th tc o DT nghim thu cell 2G Cc dng trm 2G:

3 cell E, F, G vi BCCH bng tn 900 v TCH bng tn 900. (Concentic GSM). 6 cell A, B, C vi BCCH v TCH bng tn 1800 v E, F, G vi BCCH v TCH

bng tn 900. (Dual BCCH).

ch idle, cc sector c kim tra nh sau:

Mi sector c vng phc v ph hp mc mong i.

Chn li cell t trm kim tra ti cc trm ln cn.

Chn li cell t cc trm ln cn ti trm kim tra.

Chn li cell gia cc sector theo chiu kim ng h v ngc chiu kim ng h.

ch dedicated, cc sector c kim tra nh sau:


Chuyn giao t cc trm ln cn ti trm kim tra.

Chuyn giao gia cc sector theo chiu kim ng h v ngc chiu kim ng h.

Mc chnh lch gia cc knh hopping khng vt qu 15dbm, nu c th cn kim tra v x l vn phn cng v TRX li.

Cc bi o c thc hin cho tng cell ca trm:

10 cuc gi thoi vi thi gian 10s

Phn tch cc cuc gi thit lp khng thnh cng v cc cuc gi ri.

1 tin nhn c gi v nhn

Kim tra dch v SMS

Kt ni internet

Kim tra PDP (Packet Data Protocol)

Vi cc trm dual BCCH th tc kim tra cc cell E, F, G tng t cc cell A, B, C.


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5.2.2. Th tc o DT nghim thu cell 3G ch idle, cc sector c kim tra nh sau:


Chn li cell t trm kim tra ti cc trm ln cn.

Chn li cell t cc trm ln cn ti trm kim tra.

ch dedicated, cc sector c kim tra nh sau:

Mi sector c vng ph RSCP v Ec/No ph hp.

Chuyn giao mm gia trm kim tra v cc trm ln cn.

Cc bi o c thc hin cho tng cell ca trm:

5 cuc gi thoi (60s - 30s) 2 cuc gi c nh.

3 cuc gi video.

1 tin nhn gi v nhn kim tra dch v SMS.

Kim tra IRAT (chuyn giao t 3G sang 2G) Chn li cell t 2G sang 3G

Kt ni internet

Kim tra PDP (3G-R99): thng lng trn 350 Kbit/s Kim tra 3.5G-HSDPA: thng lng trn 1 Mbit/s (vi u cui c h tr

HSDPA).


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5.3. o so snh (Benchmarking)


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5.4. Cc vn trm 2G 5.4.1. Cho sector v cho feeder 5.4.1.1. Cho sector


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Cho ton b sector (c GSM v DSC)


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Cho DSC

V d


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Mt trc S2 GSM, MS1 ch dedicated

Mt trc S3 GSM ch dedicated


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Mt trc S2 DSC, MS1 ch dedicated

Mt trc S3 DSC, MS1 ch dedicated


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Cho GSM




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Mt trc S2 kha vo DSC

Mt trc S3 kha vo DSC


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5.4.1.2. Cho feeder Cho feeder GSM


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Cho feeder DSC


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V d

Mt trc S2 DSC

Mt trc S3 DSC


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Mt trc S2 kha vo S3

Mt trc S3 kha vo S2

Cc trng hp cho sector v cho feeder trm 3G tng t trm 2G.


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5.4.2. Cht lng km Rx qual tng ng vi t l li bit BER (Bit Error Rate) nh hng bi can nhiu. C 2 loi can nhiu:

Can nhiu ng knh Can nhiu cc knh ln cn

Can nhiu xut hin trong ca s nhy tn (C/I) C/I: t s sng mang trn nhiu Nhiu cao >>> C/I thp >>> Rx qual km >>> SQI km Nu c tn s nhiu cn thay i bng tn s khc.

V d

Tn s 518 v 531 can nhiu (C/I thp) nn cht lng km. Khuyn ngh: thay i 2 tn s bng tn s khng b can nhiu


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5.4.3. DTRU li DTRU: Dual Transceiver Unit, b thu pht kp pht ra 2 tn s

V d

Gii php: thay th DTRU li.


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5.4.4. Over shooting Cell c vng ph qu xa chng ln ln vng ph cc cell khc.


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5.4.5. Vng ph km 5.4.6. Cuc gi ri Nguyn nhn c th do:

Cht lng km do can nhiu TRX li Vng ph km Vn truyn sng

5.4.7. Cuc gi b Block Nguyn nhn c th do:

Qu ti cell Cht lng km do can nhiu TRX li Vng ph km Vn truyn sng MS qu xa BTS ( MAX TA = 63)

5.4.8. Li chuyn giao MS khng th kt ni c vi cell mc tiu nguyn nhn do cht lng km hoc vng ph km hoc qu ti nn MS quay li bt vo cell c.


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5.5. Cc vn trm 3G 5.5.1. Cho sector Tng t cc trng hp ca trm 2G

5.5.2. Vng ph km 5.5.3. Pilot pollution Trng hp c nhiu pilot c mc tn hiu tng ng nhau ph cng mt khu vc m khng c pilot chnh dn n Eq/No km, c th gy ra rt cuc gi v lm gim dung lng.

Khuyn ngh:

Gim tilt cc anten ca cc trm xung quanh gim nhiu gy ra bi chng ti cell chnh.

Tng cng sut ca mt trong s cc pilot hoc gim cng sut ca cc cell xung quanh.

iu chnh hng anten (azimuth) 5.5.4. Thiu cell ln cn Hin tng pht hin cell c mc RSCP cao m khng c thm vo danh sch AS dn n Eq/No km.

5.5.5. Over shooting 5.5.6. Cuc gi ri Nguyn nhn c th do:

Nhiu pilot (pilot pollution) Vng ph km (RSCP thp) Cht lng km (Ec/No) Thiu cell ln cn Over shooting Nhiu ng xung Nhiu ng ln Vn truyn sng


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5.5.7. Cuc gi b Block Nguyn nhn c th do:

Cell qu ti Nhiu ng ln Ec/No km Li phn cng Vn truyn sng

5.5.8. Li IRAT (Chuyn giao t 3G sang 2G) RSCP gim di ngng IRAT nhng khng c th tc IRAT no c thc hin dn n cuc gi b ri.

Li IRAT xy ra do thiu cell 2G ln cn.

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Tai lieu huong dan Drive Test.pdf