Trao doi hgc thudt & Thdng tin Khoa hgc Cdng nghe
QUY HOACH VA TOI U U HOA MANG v 6 TUYEN IMT
TS. NGUYEN CANH MINH Ba mdn Ky thugt Vien thdng Khoa Biin - Bien tir
Trudng Bui hpc Giao thiing Van tdi
Tdm tat: Trong thong tin di dong vdn di quy hoach vd tdt uu hoa mgng vd tuyin Id phuc lap nhdt vd ddi hdi nhieu cong sue. Bdi bdo ddnh cho viec mo la phuang phdp. cdc cong doan vd quy trinh quy hogch mang vo tuyen co linh din dgc thii riing cua cdc giao dt^n vo tuyin IMT (quy hogch md ngau nhiin, tinh todn chuyin giao mim vd nhieu hen Irong hi Ihdng UMTS, cdc ddc diim quy hogch viing phti) Ddng thdi dua ra cdu tnic cdc thudt todn ca ban trin ca sd linh lodn quy dudng truyin
Summary: In mobile communications, wire less network planning and optimization issues are the most complex and require a lot of works The paper describes methodologies, processes and planning steps taking account on specific specifications of IMT wireless inlerfaces(pseudo random code planning, soft handover calculation and interference inside UMTS .system as well as coverage planning features). In the meanwhile, the basic algorithms are .slated basing on link budget calculation.
I. DAT VAN OE
Mgng vd tuyen dam bao truy nhip khdng diy diu cudi thue bao den tai nguyen mgng. Tinh phuc tgp ciia nd do mdt logt cac yeu td:
• Tinh ddng cua trgng thai giao dien vd tuyin cung nhu dp phirc tgp va dgc thii ciia viee quy hogch mgng vd tuyen bdi nhieu ndi he thdng ma mirc thay ddi ddng phu thupc vao tai hien thdi cua mgng vd tuyen;
• Dgc thil xac dinh va viec thuc hien dilu kien tuang thich trudng dien tii' do tinh dpng thay ddi nang lugng d giao dien vd tuyin;
• Sir can thiet sir dung hieu qui tii nguyen tan sd dupc cip phat;
• Sir can thiet va die thii phdi hpp dirdng bien (ranh gidi) ciia mang UMTS,
Ngoai ra giao dien vd tuyin d m6i giai dogn trong tien trinh phat trien cd nhung die diem rieng cin tinh den sir tuang thich khi danh-gia thich ting trudng dien tir.
IL NOI DUNG
1. Cac giai doan phat trien giao dien vo tuyen UMTS
Tiln trinh phat triln he thing IMT (Intemational Mobile Telecommunications) cd thi chia thanh ba chu trinh cdng nghe : GSM/EDGE, UMTS/HSPA va LTE.
194 Tap chi KHOA HQC GIAO THONG VAN TAI So 43 - 09/2013
Trao ddi hoc thudt & Thdng tin Khoa hgc Cdng nghe Cac giai doan hoan thien giao dien vd tuyin UMTS dugc xac djnh qua cac phien ban tuang ung die ta 3GPP va dugc md t i tren hinh I [ I ].
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Hinh 1. Cdc gtal dogn phdi tnin giao dien vo tuyin UMTS 2. Dac diem quy hoach mang vd tuyen phan chia kenh theo ma UMTS
a. Dgc diem quy hogch tdn sd mgng UMTS
Quy hoach tin sd mgng UMTS li qui trinh da chuan hda nhung khdng ddi hdi kbit khe nhu mgng GSM do chi sii dung mdt sd tan sd sdng mang Khac vdi GSM sir dung phuang phip logi bd nhieu ben trong he thdng, d UMTS la phan chia muc ddng dlu luu lugng thea mot sd kenh tin sd. Hinh 2 dua ra cac yeu cau quy hogch tan sd UMTS.
Hinh 2. Cdc yeu cdu quy hogch ldn so UMTS
Khi dii tii nguyen tin sd. d UMTS cd the sir dung cac so dd sir dung tan so lap lai cho phep giam "su can thiep'' ciia cic d lan can den gidi ban viing phuc vu nhu tren hinh 3 [1]. Hinh 3c dua ra sa dd su dung tan sd lap lgi tdi uu cho phep su dung mem hon cac tin sd,
Khi quy hogch tin sd d mang UMTS/HSDPA cd thi xet ba phuang an:
• Thilt lap mgng HSDPA d tan sd rieng biet;
• Dgt mgng HSDPA tren mgng Re!'99/Rer4 vdi tan sd chung;
• Thilt lap cac phin mgng HSDPA dtin sd rieng biet.
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Trao doi hgc thudt & Thdng tin Khoa hgc Cdng nghe
Hinh 3. Sa do sir dung Idn so lap lai trong UMTS ' b. Quy hogch ma ngau nhien hda a mgng UMTS
Quy hogch ma ngau nhien cdn gpi la quy hoach cac d lan can, Cd 512 ma ban diu sir dung khi quy hogch. Thuc te cac setor dugc phan chia bang cic mi nay. Khi quy hogch ma ngau nhien can xac dinh nguon du triJ ma cho cac d ben trong (micro-, pico-, femto-d) vi cic d bo xung mdi.
Cac tieu chi chinh khi quy hoach ma ngau nhien:
• Khoang each giira 2 d su dung tan sd lap Igi chinh cimg mdt ma d mdt tan sd sdng mang chung khdng nhd han 4 lin khoang each giira cac site;
• Chinh cung mpt mi ngiu nhien khong sir dung lgi d mdt setor (tdt ban ca), c. Dgc diem quy hogch vitng phii
Yeu td chinh de xic dinh viing phu d d UMTS la kenh vat ly danh rieng dudng xudng CPICH. Chit lugng CPICH cd thi do tr^rc tilp bing 2 tham sd CPICH RSCP (Received Signal Code Power) va CPICH EJl^ Khi quy hogch sir dung I s6 tieu chuin mi nhd dd tgo ra viing phii hpp Iy ciia d:
• Xic suit yeu ciu viing phu p theo tham sd CPICH EJU (CPICH E^Io coverage):
p{ CPICH Ec/Io >(CPICH Eyi„)rec|} >95%, {xac suit trung binh p ciia tham sd CPICH E,/Io khdng nhd ban gia trj yeu cau(CPICH E/Io) req}
• Xac suit yeu ciu vimg phu p theo tham sd CPICH RSCP(CPICH RSCP coverage):
p{CPICH RSCP> (CPICH RSCP)n,q} > 95%.
Quy hoach mgng theo tieu chuan nay khdng nhat thiet va cd the sir dung eho cac die tinh viing phii trong tda nhi (Indoor) do phit tram gdc phia ngoii.
• Ty sd tin hieu tren tgp am yeu cau Ei/No- rieng cho mdi logi djch vu vi cho mdi hudng len vi xudng DL/UL (DL and UL service coverage);
p{Ei/No>(Eb/No)re„}>95%, d day Eb - nang lugng bit, N,,- mat dp phd cdng suit tgp am gdm tgp im ben trong may thu va nhilu ben trong he thdng ciia ban than d vi tir cac d lin cgn, trir tin hieu huu dung.
196 Tgp chi KHOA HOC GIAO T H 6 N G VAN TAI So 43 - 09/2013
Trao ddi hgc thudt & Thdng tin Khoa hoc Cdng nghe Vdi cic tieu chuan dua ra d tren vimg phii can dugc quy hogch dl thuc hien can bing nang lupng giii-a cac kenh sau:
• Kenh CPICH & cac kenh vat ly luu Iuang(kenh du' lieu & kenh rieng phuc vu chiing).
• Cic kenh vat Iy dir lieu d dudng xudng & dudng len.
Trong quy hogch vimg phii d HSDPA, khi khdng gidi hgn bdi tinh tuang thich cua trudng dien tir, kich thudc cua nd dugc xic dinh bing tii nguyen nang lugng kenh UL, cdn dung krpng cua nd dugc xic dinh bing tii nguyen nang lugng kenh DL. Khi hgn chl do tinh tuang thich cua trudng dien tu, cin dilu ehinh vimg phu sdng theo ci hai kenh UL va DL.
v l phuong dien chuyln giao mem, khi quy hogch mang UMTS cin quan tam din tham sd hinh hpc G (Geometry) ctia d. Tham sd nay cho phep tdi uu hoa chl do hogt ddng mgng vo tuyin theo cic chi lieu chuyen giao mem, cung nhu theo ning lupng. Tham sd G dugc xac djnh bing cdng thirc [I]:
y^ RSCP,
g - I ° r _ ^ CPICH E^/IJ, ^IJ
r r CPICH E ^ / i , j ,
U,' mat dp phd cdng suit cac tin hieu CPICH nhgn tir mdi 6 AS;!,,^,- matdg pho cdng suit cua nhilu tir cac d khdng vao chpn tich cue; IQ - tdng cdng suit nhgn dugc d d; N^, - mat dp phd tgp am ben trong miy thu; RSCP, - cdng suat mi tin hieu baa tieu i.
Bieu thuc (I) cho phep tinh toan anh hudng kich thudc chpn tich cue ciia eae 6 den mirc nhieu trong he thdng vi vgy dap irng tii nguyen vd tuyen.
d. Quy hogch mgng khi tinh todn chuyen giao mem
Quy hogch mang vd tuyen hudng den dam bao thiet lap dimg cac tham sd chuyen giao mem va xac djnh viing phuc vu de xac suat chuyen giao mem khong vuot qui gii trj yeu cau.
Mdt trong cac nhiem vu quy hogch la hd trg mirc tdn hao djnh trudc khi chuyen giao mem. Dieu nay cd the dgt dugc bang each tdi uu hda tham sd G ciia d.
Ve chuyen giao mem d che do HSDPA nd thuc hien chi theo cac kenh "thong thudng"
UMTS(Rer99) do vgy viec quy hogch mang vo tuyen cd 1 sd die diem rieng, e. Sir cdn thiet tinh todn nhieu ben trong he thong
Tdn tgi nhieu trong he thdng la h? thdng rieng biet phan chia kenh theo ma, Muc nhieu niy lien quan tryc tilp vdi tai mang vi co the thay ddi thudng xuyen. Viec tinh toan trudc chiing khi quy hogch can cho viec tinh loan ning lugng dudng truyen yeu cau ddi d cac dieu kien hogt ddng khac nhau eua mang. Ngoii ra inh hudng nhieu trong he thdng d UMTS thudng dinh gia d dgng vugt mii-c tap am ben trong miy thu khi d tai luu lugng khic nhau.
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Trao ddi hoc thudt & Thdng tin Khoa hgc Cdng ngne
f. Tinh todn viec phdn phoi cdng sudt trgm gdc d chi do kit hgp Iruyen dir lieu (Rel'99&HSDPA)
Mgt sd dgc thu d quy hogch mang vd tuyen UMTS xuit hien trong trudng hgp khi tai nguyen trgm gdc sir dung kit hpp di truyen dir lieu d dgng Rer99 vi HSDPA. Trong trudng hpp bit ky quy hoach cin thuc hien rieng cho mdi chl dp truyln dir lieu (Rer99 & HSDPA) vdi viec tinh loan phan cdng suit danh cho nd. Bing ket qua quy hogch nhu vay can cin bang giiia 2 chl dp theo vimg phuc vu va tdi uu theo dung lugng ciia mdi chl dp.
in. CAC THUAT TOAN QUY HOACH \ .\ T6I U U H 6 \ MANG VO TU\ FN UMTS 2.1. Cdu trdc thudt todn quy hogch vd toi iru hoa mgng vd tuyen
Quy hogch mang cd the chia thanh 3 giai dogn: Quy hogch, tdi uu hda ban diu va tdi uu hoa thudng xuyen. Quy trinh quy hoach mang vd tuyen UMTS chia thanh 2 cdng dogn: quy hoach ban dau va quy hogch chi tiet. O giai doan tdi uu hda ban diu kiem tra tinh diing din ciia viec chpn cac tham sd dua ra ban dau, chinh xic cac dieu kien mdi trudng truyen dan va xac djnh cic dac tinh he thdng con vd tuyen. Trong qui trinh tdi hda thudng xuyen thuc hien viec nang cao tiep theo hieu nang mgng cd tinh den miic tang nhu cau.
Giai dogn dau cua viec quy hoach dua ra cic yeu cau diu vao vdi mgng vd tuyen, xac djnh cac nhiem vu ca ban cho viec thiet lap mgng va cac tham sd cu the ciia nd. Cau triic chung thuat toan quy hoach va tdi uu hda mang vo tuyen UMTS dua ra tren hinh 4.
Hinh 4. Cdc thudt todn chung cho quy hogch vd tdi uu hda mang vd tuyin UMTS Tren ca sd nghien ciru cac thugt toan chung va eac dac diem quy hogch mgng vd tuyen phan chia kenh theo ma da dua ra thuat toin cu thi tinh toin vimg phii theo kenh dudng len UL (hinh 5) cung nhu cac thugt toan khic [1]:
• Thugt toin^inh toan vimg phii theo kenh dudng xudng R99;
198 Tap chi KHOA HOC GIAO THONG VAN TAI So 43 - 09/2013
Trao ddi hoc thudt & Thdng tin Khoa hoc Cdng nghi
• Thugt toan tinh toin viing phu theo kenh CPICH;
• Thuit toin tinh toan cdng suit yeu theo kenh CPICH;
• Thugt toan tinh toan vimg phO theo kenh CPICH;
• Thuat toin tinh dung lugng d kenh HSDPA.
C o n g
(HS-DPCCH)
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tTinh 5. Thudt todn linh todn vimg phu iheo kenh dudng tin (UL) 2.2. Tinh phiic tgp ciia qud trinh quy hogch
Quy hogch mgng vd tuyen UMTS la mot qua trinh rat phirc tgp lien quan den nhieu ylu to va ddi hdi cin dua ra cac ca sd phuang phap luin eho phep tinh toin cic yeu td nay va trudc tien la danh gia cic chi tieu cin dgt dugc ciia mgng xay dung. Hien nay cd hang logt phuang phip dugc dua ra ciia cic nha cung cap thiet bj. Cac phuong phap nay cd mdt trinh tu co ban chung, tuy nhien cung cd I sd dgc dilm rieng. Tit ci cic phuong phip quy hogch dugc ghi nhgn deu dua tren tinh toin quy ning lupng dudng truyen,
III. KET LUAN
Vj^c nghien cuu quy trinh vi cac thuat toin co tinh den cac cac dac diem rieng ciia cic giao dien vd tuyin IMT/UMTS giup cho viec tim hilu va sir dung hieu qui bp cdng cu quy hogch vi toi uu hda mang trong thyc tl.
Tii li£u tham kh:io
[1]. B. F. CKpbiiiHUKoa, "PaiiHonoflCHCTeMbi UMTS/LTE", Vhn. 'TopjiHaa JIHHHH", 2012.
[2]. Nguyin Phgm Anh Dung, Hoc viSn Cong nghe BCVT: "Lo trinh phit Uiln thong tin di dong 3G ISn 4G", 12/2008*
Phin bi?n: TS. Tran Hoai Trung
Tgp chi KHOA HQC GIAO THONG VAN TAI S6 43 - 09/2013 199
