Chuyên đề tốt nghiệp: Nghiên cứu chất lượng dịch vụ trong Wimax

Chuyên đề Nghiên cứu chất lượng dịch vụ trong Wimax trình bày nội dung tổng quan về hệ thống WiMax, các kĩ thuật sử dụng trong WiMax, giải pháp công nghệ WiMax, ứng dụng công nghệ WiMax. Để biết rõ hơn về nội dung chi tiết, mời các bạn cùng tham khảo.

BQ MAO DIJC VA DAO TAO TRUUNG DAI HQC THANG LONG

—o0o

1 THANG LONG

UNIVERSITY

CHUYEN DE TOT NGHIEP

NGHIEN CITU CHAT LONG DICH vu

TRONG WIMAX

Gila vien hurting chin Sinh viers thyc hi§n

MA sink vien Chuyen nginh

:ThS Holing Tryng Minh :Phan Tien TAng

:A13162 :Tin vien thong

HA NQI - 2013

1.3.3 Clic bang tin duqc d8 nu& cho WiMAX tren the gitri 8 1.3.4 Citc bang tin Is Viet Nam co khe Ming dinh cho WiMAX 9

2.1.1 Su inh huong cua mai trubng den viec truyen dAn 17

2.13 CEng nghe OFDM yeti kha Wing km the nhieu 19

2.1.6 Khoing bio 4 (GUARD PERIOD) 22

4.1 M8 hinh triton khai WIMAX Oleic yen an tray 4p di Ong 57

4.2 M8 hinh triton khai WIMAX veti the yen can tray 4p c6 djnh 58

4.4 Xu hiftng can wimax trong that gian tot trait qui ma thi gi6i 67

DANH SACH HiNH YE

With 1.3 Bin kinh cell quan 110 Ai dilu chi thich nghi 11

With 2.4 So sinh song mang cia OFDM yeti cic hinh thirc Mg& thong 19

HInh 2.7 Gin dis IQ cos 16QAM khi dung mit Gray 22 Hinh 2.8 Chin lchoing thbi gian &to 4 cho m8i hieu 23

Hirsh 2.10 Ctiu frac Tulin thbi gian cial0 hieu OFDM 24

Mirth 2.13 So slip /cep theo hai chieu trong OFDMA 26

HInh 3.9 Hieu cmg kenh con hoe (sub channelization) 48 Hinh 3.10 Dieu chi thich nghi vi mi h6a dtra tren khoing each yeti BS 49 Hinh 3.11 Co che yeu au lap lai khi 16i xiy ra 51

Minh 4.3 Binh Si ye thiet bj tram g6c BS dugs lip On DSc nhl diem BDVHX 64 HInh 4.4 HInh inh thrc te thiet hi Out door phis Ichich hAng 65 Hirsh 4.5 Hinh inh nu& din Ti Van troy cep Internet 65

DANH SACH BANG BLEU

Bang 3.1 Cie loci khoi bao mot se dung tong IFFF 802.16-2004 42 Bang 3.2 MA sea 16i dbi yeti cac phuang then dieu chi 43

Bang 3.4 Cie phuang thee dieu chi vi MA has dtrqc he trq trong 802.16e 49

Bit error ratio

Base station network interface

Base station

Bandwidth

Broadband wireless access

code division multiple access

Certification authority

Cyclic Prefix

Customer Premise Equipment

Common part sublayer

Cyclic redundancy check

Convergence sublayer

Data encryption standard

Dynamic frequency selection

Discrete Fourier Transform

Dynamic host configuration

Fast Base Station Switching

Frequency Division Multiple

Access

Frequency division duplex

Forward error correction

Fast Fourier transform

Fixed satellite service

Fixed wireless access

Global positioning satellite

Half-duplex FDD

Hard Handoff

Information element

Internet Engineering Task Force

Inverse Discrete Fourier Transform

Inversion Fast Fourier transform

He th6ng anten thich nghi Khali cAp phep

C6 ging toi da

Ty le lei bit Giao dien gins tram g6c vi mong Tram g6c

Bang thong Truy nh$p khong day bang rung

Da truy nh$p chia Quyln chung thoc Tien t6 tan hob Thiet bj din cu6i thue bao Lap con plan chung

!Gem tra yang du Lap con hOi to Tieu chuin mat ma du lieu Loa chip tin se dung Bien al Fourier raj roc The toe du hinh the khang c6 dinh

Huang xuting Dieu khan m#t ma Bang mat ma then to M$t ma-m#t ma

Ma Ma se I8i throe Vien lieu chum ten thong Chau

Au Chuyen d6i tom g6c nhanh

Da truy nh$p phan chia tin se

Song cang chia tin se

Sea 181 huang di Bien dig Fourier nhanh Djch vo ye tinh c6 djnh Truy nh$p khang day c6 dinh

Ve tinh ctinh vj tan ciu FDD ben song cong Chuyen yang can Phiin to thong tin

TO chat Icy su that Ice Internet Bien doi Fourier rai roc ngtrqc Bien d6i Fourier nguqc nhanh

Key encryption key

Local area network

Local multipoint distriution service

Line of sight

Medium access control layer

Metropolitan area network

Macro Diversity Handover

Multi input Multi output

Multichannel multipoint

distribution service

Moving Picture Experts Group

Network configuration

Non line of sight

Non-real-time polling service

Orthogonal frequency division

multiplexing

Orthogonal frequency division

multiple access

Peak-to Average Power Ratio

Personal Computer Memory Card

International Association

Personal Digital Assistant

Plesiochronous digital hierarchy

Protocol data unit

Packet Error Rate

Security association identifier

Service access point

Thb tic Internet Hiep hOi viers th8ng Qu6c ti

Khoa met ma Ichoa mons 110i h0 Djch vv phan ph6i da diem nOi hitt

Tia live xa Lop (lieu khiin truy nhip m8i trubng

Mang khu Arc thanh phi Chuyin giao da clang rieng

Da dubng vim da dubng ra Djch vp phin ph6i da diim da kenh

Nhom chuyen gia nghien cuu WI gang

Ciu hinh mpg Tia kheng tnrc xa

Djch vµ tham db kheing thai gian thrc

Ghep kenh chia tin s6 trvc giao

Da truy nhep chia tin sea tnrc giao

Cong suit Wong d6i cvc dai Hiep hOi quOc to ye tim mach nher ala may tinh ca nhan That bi vv s6 ca nhin Phan cep s6 din ding b0 Don vi da lieu filo tic

Ty le 16i gei Lop vat lf Quin ly khoi rieng Diem da diem

Thb tic diem-diem Dieu chi bien dO au phuong Chit luong djch vi

Khoa djch pha ciu phuong Yeu ciu

Djch vi them db thbi gian thvc Thu

Tip hop bao met

BO nhin clang tap hop &to met Diem truy nh$p djch vi

Service Flow Identifier

Simple Network Management

Protocol

Signal-to-noise ratio

Subscriber Station

Space time coding

Time division duplex

Time division multiplex

Time division multiple access

Traffic encryption key

Transmission

Unsolicited grant service

Uplink

Dan vi dtt lieu djch Luang djch va

BO nh$n clang luang djch va Tha tac quan 15, mang dcm gian

TS, le tin hieu/tap am Tram thus bao

Ma thbi gian Idieng gian Song dog chia thbi gian Ghep kenh chia thbi gian

Da truy nhap Phan chia thin gian Khoi mat ma luu ltrong

Truyen dAn Djch va cap ph& tkr nguyen Huang len

Len NOI DAU

Ngaly nay nhu ciu th8ng tin lien lac chit con ngtrai ngay cling cao, nhit 11 d6i v6i cac thiet bj khang day t6c dO cao, bang thong Ong nhu dien thoai Ichong day, Internet kh8ng day de mqi ngueri c6 the lien lac vet nhau 6 mai 16c, mai non vh quasi tang hen la viec ma rOng din tri cho nguiri din 6 cac vung xa x8i heo 1>inh tren dit nuesc ta, nai mat ca se ha tang vier th8ng chua den duct Hien nay di c6 rat nhieu thong mang kh8ng day ra dal nhu la WiFi, bluetooth va met trong se d6 c6 the dap Ong

duqc nhu ciu tren IA WiMax WiMAX chat you cung cap djch vu intemet kh8ng day

vai gist thanh re, t6c dO truyin cao kit n6i den cac thiet bj diu cu6i trong mat Ichoang catch truyen 16n

Viec triers khai he thong con g#p nhieu kh6 khan do nhieu nguyen nhan khich quan cOng nhu chat quan VI vay, em chip de tIi "nghien cuts chat lucmg djch vµ trong WiMAX" Trong gi6i hen chuyen di nay, em di tim hieu kY thuot vI nhOng Ich6 khan cos cOng nghe WiMAX khi ap dung rang rill 6 nu& ta

Chuyen de g6m c6 b6n chuong:

Chuang 1: T6ng quan ve he th6ng WiMAX

Chuang 2: Cac ki thult stl dung trong WiMAX

Chuang 3: Gill phap c8ng nghe WiMAX

Chuang 4: Ling dung c8ng nghe WiMax

Do died gian cOng nhu trInh dO con Ilan chi, chuyen de khOng tranh khOi nhOng thieu sot, em rot mong nhan duqc y kien Nag g6p

Em xin chan thanh cam an they Hoang Trang Minh, ngtrei dit dinh huang, huang den vi tan tinh chi biro em hohn thanks chuyen de nay

Phan Tien Tking

CHIXYNG 1: TONG QUAN VE H$ THONG WiMAX

Mobile WiMAX (WiMAX di dung): dua tren fieu chuin IEEE 802.16e, h8 trq cho clang di dung, cung cep khi tiling chuyen yang - handoff vi chuyen mpg - roaming Tieu chuin nay sir dung phuong thirc da truy c$p ghip kenh chia tin so tnrc giao OFDMA (Orthogonnal Frequency Division Multiple Access) - li su ph6i hqp cc5a ky thuot ghep kenh va lcy thuit phan chia tin s6 c6 tinh chit Ulm giao, nit pht hqp voi m8i trutng truyen dAn da dubng nhim tang thong luqng ding nhu dung luong

tang dO linh hoot trong vies quin ly tii nguyen, liin dung tai da ph6 tin, chi thin khh Ming phh song yeti citc loci dja hinh da dung

WiMAX da ducc phat trien vi ;chic phuc duct nhitng nhuqc diem cult citc c8ng nghe truy c$p bang rang tru6c day, cu the:

Phan Tien Tking

Trang 2

TONG QUAN VE Ht THONG WiMAX

— Ciu true mem deo: WiMAX h6 trq clic ciu trim he thong bao g6m diem da diem, c8ng nghe lir& (mesh) vi phu sting khip mqi not Dieu lchien truy nh$p m8i twang - MAC, phut:mg tien truyen din h6 trq diem - da diem va dich vu rang khip b6i mOt khe thin gian cho m6i tram di dang (MS) Neu c6 duy nhit mOt MS trong ming, tram g6c (BS) sE lien lac v6i MS tren ca set diem - diem Mat BS trong mOt ciu hinh diem - diem c6 the sir ding anten chum hgp han a bao phu clic khoing each xa han

— Chit lueing djch vu QoS: WiMAX c6 the dirge t6i in dOng d6i yen h6n hqp

luu luqng sE duct mang CO 4 loci djch vu dirge h6 trq: djch vu tip phut to nguyen (UGS), djch vu hei Wong thbi gian thvc (rtPS), djch vu hal yang khOng thin gian thirc (nrtPS), n6 km tot nhit (BE)

— Tries kluti nhanh, chi phi thip: So sloth von trien khai care giii phap co day, WiMAX yeu eau it ho#c kh8ng eh bit rent sir xay dying thiet lop ben ngoli VI

du, duo h6 de Mo ranh cat dubng cap thi kh8ng yeu c$u Ngotli ra, doa ten clic chuin m6 cha WiMAX, se kh8ng c6 so dOc guy& ye lieu chain nay, din den viec chnh trash chit nhilu nha sin xuit, lam cho chi phi diu to mOt he thong gut= ding ke

— Djch vu da mat: Cach thirc not ma QoS dirge pha ► phtit n6i chung doa vac so thea thu$n mire djch vu (SLA - Service Level Agreement) gitta nha cung cap dich vu va ngubi sir ding cu6i can Chi flit han, mOt nha cung alp djch vu c6 the cung cap clic SLA khac nhau tai care thug bao ldiac nhau, thklm chi till nlittng ngubi dhng !chat nhau sir ding sung MS Cung cep truy nh$p bang rung co dinh tong Meng khu voe d8 thi va ngotti 8, not chit luqng cap deg thl kbm ho#c dim vao 16.6 khan, khlc phuc thiet bj s6 tong nhttng yang met

da thip not ml cat nhan t6 c8ng nghe vh kinh ti thyt hien phut trier bang rang rut thich thirc

— Tinh Wang thich: WiMAX duct )(Ay (long de tors thinh mOt chuin quOc te,

Mo ra so a ding d6i vdi ngubi dOng cu6i sung a truyen tai vi sir dyng MS chit hq 6 clic vi tri khitc nhau, hetet yeti cat nhti cung cap dich vu khac nhau Tinh tucmg thich bito ve so ditu to cua mOt nha van hash ban diu vi n6 c6 the chqn lira thiet bi ttr care nhi thiet

— Di ding: IEEE 802.16e b6 sung them tic dec diem chinh h6 trq khi !rang di dung Nhttng cii den lap vat ly OFDM (ghep kenh phin chia tin so titre giao)

va OFDMA (da truy nh$p pit chia tin s6 trot giao) de h6 trq cat thiet bi va the dich sit tong mOt m8i tnrbng di dung Nhttng cii lien nay, bao g6m Phan Tien Tang

OFDMA mit rung duqc, MEMO (Multi In Multi Out - nhieu diu vac nhieu diu ra), vi h8 thy del vat the dO idle/sleep vit handoff, se cho phep kha Wing

di dung (fly du 6 the dO tea 160 km/h Mang WiMAX di dung cho phep ngtriti sfr dung c6 the truy cop Internet khang day bang thong rung Ali bit cu dfu c6 phi sting WiMAX

— Hog dung NLOS: Khii tiling hog dung curt mang WiMAX ma Idling did hei tern nun thing gitta BS vi MS KM Wing My cos n6 gift') ac sin phim WiMAX phAn phit dii thong rung trong met mei truing NLOS

— Phu sting rung han: WiMAX h8 trq dung nhieu mire dieu chi, bao gem BPSK, QPSK, 16QAM, 64QAM Khi yeu au yeti bO khuich dg tong suit cao vi hog dung vol di& the mire thip (vi du BPSK ho(ic QPSK) Cac he thong WiMAX c6 the phi sang mOt yang dirt 13± rung !chi dutrng truyin gifts

BS vi MS kiting bj an frit Met rung pham vi bj giOi hp hien tai mitt WLAN ding cung (hotspot) den phi= vi rung (hotzone) O nhttng dieu kien tot nil&

ce the dot (bye phgn vi phi sting 50 km v6i toe dO dit lieu bj ha thip (mOt vii Mbit/s), pham vi phi sting dien hinhli gin 5 km v6i CPE (NLOS) trong nhi vit gin 15km vii mOt CPE duet not vii mOt anten ben ngoii (LOS)

— Dung lucmg cao: C6 the dot duce dung luqng 75 Mbit/s cho cac tram g6c yeti mOt kenh 20 MHz trong cac dieu kien truyin song tot nhit

— Tinh mei rung: Chuin 802.16 -2004 M trq cac dii th8ng kenh dui s6 v8 tuyen (RF) mem deo vi sfr dung loi the kenh tin s6 nay nhu la mOt each di tang dung luqng martg Chuin cftng djnh r8 h8 trq deli vai TPC (dieu khien c8ng suit phit) vh cic phep do chit luqng kenh nhu the Gang cu them vtio de h8 trq sa dung ph6 hieu quit Chuin dA dupe thiet Ice de 4t tt le len tai hang tram th#m chi hang nghin nguOi sa dung trong mOt kenh RF H8 trq nhieu kenh cho Step cac nhb the to thiet bj cung cap mOt phuang tien de chi trcmg vho phi= vi su dung ph6 vi nlang quy djnh cip phit duce mai r8 bid cac nhi v#n hinh trong the thj truing quac to thay deli !chic nhau

— Bin mkft: Bing each ma hOa the lien kit v8 tuyin gifta BS vi MS, su dung chuin ma hba tien tien AES, dim bao sv tan von ctia Ott lieu trao deli qua giao dien v6 tuyen Cung cip cho ac nha v#n Minh vii sv bito ve manh cheng lai nhftng hAnh vi dinh cip djch vu

Phan Tien Ting

Trang 4

TONG QUAN VE H$ THONG WiMAX

1.2 Cic chuAn chit WiMAX

1.2.1 Chan IEEE 802.16-2001

ChuAn IEEE 802.16-2001 duqc hoar) think vho thing 10/2001 vh duqc cemg 136

vho 4/2002, djnh nghia dac ti k9 thu$t giao din kitting gian WirelessMANni cho Mc ming vbng d8 thj

Dac diem chinh Ma IEEE 802.16-2001:

+ Giao dies !thong gian cho he thing truy nh$p khong day bang rung do djnh host dung 6 did tin 10 - 66 GHz, cAn th6a man tim thin thing

+ Lip vat 15, PHY: WirelessMAN-SC

+ T6c dO bit: 32 -134 Mbps yeti kenh 28 MHz

+ Dieu chi QPSK, 16 QAM vi 64 QAM

+ Cic dii thong kenh 20 MHz, 25 MHz, 28 MHz

+ Ban icinh cell: 2 - 5 Ian

+ Ket n6i c6 djnh hueng, MAC TDWIDMA, QoS, bin mot

1.2.2 Chan IEEE 802.16a

Vi nhong kith khan trong then khai chuin IEEE 802.16, hueng vho vies sir dung

tin s6 tir 10 - 66 GHz, mOt dv in sou d6i c6 ten IEEE 802.16a da duqc holn thhnh vho

thing 11/2002 vh duqc c6ng b6 via thing 4/2003 Chuim nay duqc me rung h6 trq

giao dien kh8ng gian cho nhemg ten s6 trong bang tin 2-11 GHz, bao g6m ci nhttng phi cup phap vh khong cep phip vi khemg cin that man dieu ;den tim nhin thing Dac diem chinh curt IEEE 802.16a nhu sau:

+ B6 sung 802.16, cic hieu chinh MAC vi cic dac diem PHY them vho cho 2-11 GHz (NLOS)

+ Tic dO bit: teri 75Mbps yeti kenh 20 MHz

+ Dieu chi OFDMA vOl 2048 sting mang, OFDM 256 sting mang, QPSK,

16 QAM, 64 QAM

+ Dii thong kenh c6 the thay d6i gilts 1,25MHz vi 20MHz

+ Ban lcinh cell: 6 - 9 lcm

+ Lop vat PHY: WirelessMAN-OFDM, OFDMA, SCa

+ Cic chile niing MAC them vtio: h6 trq PHY OFDM vi OFDMA, h8 trq cemg nghe Mesh, ARQ

Phan Tien Tang

1.2.3 Chula,: IEEE 802.16-2004

Tilling 7/2004, chuim IEEE 802.16 - 2004 hay IEEE 802.16d dupe chip nh$n

thOng qua, ket hap cuts cac chuk IEEE 802.16 - 2001, IEEE 802.16a, ling dung LOS 6

did tan s6 10- 66 GHz vi NLOS ti did 2- 11 GHz Khii Ming v8 tuyen b6 sung nhu lh

"beam forming" vi kenh con OFDM

1.2.4 Chuin IEEE 802.16e

Chan khong day bang thong rung 802.16e vai ten gqi Mobile WiMax cho phep tram g6c ket n6i tai nhitng thiet bj dang di chuyin Chum nay gap cho the thiet bj a cac nhe sin xuit ray cti the lam viec, tutmg thich t6t voi cac thiet bj tfc ciic nha san xuit khac 802.16e hqat dung 6 cac bang tin nhe han 6 GHz, t6c dg len teri 15 Mbps yen kenh 5 MHz, ban lcinh cell to 2 - 5 km

WiMAX 802.16e c6 h6 trq handoff vi roaming Su dung SOFDMA, mOt c8ng nghe dieu the da song mang Cac nhi cung cep dich vy tan khai 802.16e cling c6 the

su dung Truing d6 cung cup dich vp c6 djnh 802.16e h6 trq cho SOFDMA cho phip s6

song mang thay d6i, ngoii the m8 hinh OFDM vi OFDMA Sr phAn chia sting mang trong m8 hinh OFDMA dirge thiet ke d6 t6i thieu inh Wing cua nhigu phis thiet bj ngutti dOng yeti anten da hueng Cu the han, 802.16e dim ra h6 trq cii den h6 trq MIMO vi AAS, cling nhu cit handoff cimg vi mem NO cling cii tien cac khi nAng tilt kiem c8ng suit cho cfic thiet bj di dung vi cic dac diem bao mot linh hoot han

Phan Tien Tang

TONG QUAN 'VE HE THONG WiMAX

Bin Icinh cell 1.7-5km 5 tai 10Ian; toi da

50 km thy thuOc vao dieu kien truyen

1.7-5km

Bang 1.1 So seinh cac chain IEEE 802.16

Voi nhftng dtic diem va su phat den cult cac chuin IEEE802.16 n6i tree, to co the 'than thiy dtrqc sulchic nhau ca ban cang nhu firth ke thira caa cic chuin nay

IEEE yin dang nghien cuv va dui ra cac chuin 802.16 mai nhim hoen thien chuin nay Vi du nhu: IEEE 802.16f-2005, IF.F.E802.16g-2007 b6 sung cho thu tyc quitn lfr ke hooch vtl djch Ai, IEEE 802.16k-2007; IFFY 802.16-2009 cling c6 tieu chart IEEE 802,16-2.004, 802.16e-2005 vi 802.16-2004/Cor1-2005, 802.16f-2005,

vi 802.16g-2007, 802.16m

1.3 Phi WiMAX

WiMAX - thiet bi mem deo se dtrqc phep hoot ding tong ca hai dai duct ding Icfr va kh8ng ducm ding Icfr

1.3.1 Bang tin piing kj

Cfic giai phap clang k9 cung cep cac tru diem chit lucmg djch vu duct chi thien cao han cac giai phitp !thong clang k9, chip nh$n NLOS tot han a cac tin s6 thip, ne

co mOt nein quy deg suit dutmg xu6ng ring han va co the h6 trq cac anten trong nhtl t6t han Giai phip (tang kfr cho phep kiem so& qua cach sir dung ph6 vil Watt

Phan Tien Tang

a Bins tin 1111nz $ 2.5 GHz

DA dirge dip ph& trong phin 16u the gi6i, bao gem bile M9, my Latin, D8ng vu Tay Au va nhieu ming caa chau A - Thai Binh Duang nhu mOt bang tin dang 1c9 MOi qu6c gia thubng cep phit dal khic nhau, vi v$y ph6 dupe cup phit qua cac vang c6 the tfr 2,495 GHz den 2,690 GHz Tong ph6 kha dung 18 195 MHz, bao gtom cac did pheng

ye Nal cac kenh MDS, gba 2.495 GHz va 2.690 GHz HO trq FDD, TDD Ph6 tren tnoi dling k9 la 22.5 MHz, mOt block 16.5 MHz vtl mOt block 6 MHz, tong s6 8 clang 1E9

b Bins tin an Id 3.5 GHz

Chau Au, vien chuin vier th8ng Chau Au dA plan ph6i dal 3,5 GHz, bit diu dirge sir dung cho WPLL, cho cac gi8i phap WiMAX clang ky T6ng ph6 khi dung thay 461 then qu6c gia nhung ned chung khoing 200MHz gifts 3,4 GHz vi 3,8 GHz

HO trq FDD, TDD MOt vii qu6c gia chi sfr dung FDD trong khi cac qu6c gia khic cho s* dung FDD hokIc TDD Ph6 ben m61 slang Icy thay d6i ta 2x5MHz den 2x56 MHz

1.3.2 Bing tin khOng ding 45 56Hz

Phan 16n cac qu6c gia tom the gi6i dA stl dung ph6 5 GHz cho Mc bang ding kheng long k9 nhu: Wing 5,15 GHz va 5,85 GHz

Cac giiti phap kitting dling 1c9 cung cep mOt vii thu$n lqi chinh ham cac gi8i phap Clang k9, bao Om chi phi ban dL thip han, rut m nhanh han, vi mOt bang chung c6 the dirge su dung 6 phin 16n the gi6i Cac ici kb My dang thu but sir quan tam v8 c6 khi Ming cho sir chip nhen bang rung nhanh ch6ng

Tuy nhien mOt giai phap kh8ng clang 1c9 thi khi nAng nhiL cao han, va nhieu sv canh tranh desi tied Mc nha kinh doanh bit dung sin cho viec trim khai MOt gi8i phip kitting clang k9 se khang duqc xem nhu mOt sv thay the cho giai phip dang ky MOi giai phip cung cep mOt thi twang khic nhau dva vio str thoa hiep gifts chi phi vi QoS

1.3.3 Cdc being tin thtyc ii xuit cho WIMAX win thi gtdrt

Cac bang tan dirge Diln dart WiMax trong xem xdt va v$n dung ca quan quip

19 tan so cac nu6c phan b6 cho WiMax la:

— Bang tin 2,3-2,4GHz (2,3GHz Band): dirge de St sti dung cho Mobile WiMAX Tai Han Qu6c bang My dit dirge trien khai cho WBA (WiBro)

— Bang tin 2,4-2,4835GHz: duqc de xuit sfr dung cho WiMAX trong Wang lai

— Bang tin 2,5-2,69GHz (2,5GHz Band): duct de St sir dung cho WiMAX di dOng trong giai don diu

— Bang tin 3,3-3,4GHz (3,3GHz Band): dirge de xuit s6r Mpg cho WiMAX c6 djnh

Phan Tien Tang

TONG QUAN VE He THONG WiMAX

— Bang ten 3,4-3,6GHz (3,5GHz Band): &roc de xuit sfr dung cho WiMAX c6 djnh trong giai door du: FWA (Fixed Wireless Access)/WBA (WideBand Access)

— Bang ten 3,6-3,8GHz: dirge de 'cult so dung cho WiMAX c6 djnh (WBA) vil cap cho Chau Au Tuy nhien, bang 3,7-3,8 GHz dit dirge dung cho ve tinh vigil tilting Chau A, nen bang ten My khong dirge st• dung cho Wimax Chau A

— Bang tin 5,725-5,850GHz: dirge di xuat s* dung cho WiMAX c6 djnh trong giai clop du

— Ngoli ra, mOt s6 bang tin Ichic phitn b6 cho BWA cOng dirge mOt so nuoc xem xat cho BWA/WiMax la: bang tin 700-800MHz (< 1GHz), bang 4,9-5,1GHz

1.3.4 Cdc bang hiss it Viet Nam cd khd niing dank cho WiMAX

— Bang tin 2,3-2,4GHz: C6 the danh (loon bang tin My cho WiMAX Bang tin 2,3-2,4GHz thich hop cho ca WiMAX c6 djnh va di (tong

— Bang tan 2,5-2,69011z: Bang tin My hien nay dang dirge s* dung nhieu cho

vi ba vi MMDS Nip thing chti yeu 6 Hi nOi wit thinh ph6 H6 Chi Minh)

Ngotti ra, bang tan nay II mOt trong cac bang tan duce de )(at su dung cho

3a Bang tin nay loi li bang tan dirge dank gia la thich hop nit& cho WiMAX

di ding va da duce Dign din WiMAX )(sic nhen chinh thtic 11 bang tin

WiMAX MOt s6 nuke cOng d1 danh bang tin nay cho WiMAX nhu My,

Mehice, Brazil, Canada, Singapo VI v$y, de nghj danh bang tin 2,5-2,69GHz cho WiMAX

— Bang tan 3,3-3,4GHz: Theo Qui hooch ph6 tin s6 VTD qu6c gia, bang tin nay duce Olin b6 cho the nghiep At Ves tuyen djnh vi, c6 djnh ve ltru ding

Ve phis clan sir va quilt' su veil chua co he thong Mc, duqc trien khai tong bang tin my Do do, c6 the cho phep s* dung WiMAX trong bang ten 3,3 - 3,4GHz

— BAng tin 3,4-3,6GHz, 3,6-3,8GHz: D6i v6i Viet Nam, he thong 4 tinh VINASAT su dung mOt s6 doon bang tan trong bang C va Ku, trong d6 cal bang ten 3,4-3,7 GHz Ngohi ra, (loon bang tan 3,7-3,8 GHz m#c de chua su dung cho VINASAT nhung c6 the dupe s* dung cho cac from mit dat lien loc v6i the he thong ve tinh !chic VI v$y kheong nen tan khai WiMAX trong bang tin 3,4-3,8 GHz

— Bang tan 5,725-5,850GHz: Hien nay, bang tin My da dupe BO qui djnh dart cho WiFi Neu cho phdp tan khai WiMAX trong bang tan My thi cOng se

hp 64 bang tin dinh cho WiFi Bang tin nay c6 the thich hop cho the he Phan Tien 'fling

thong WiMAX b vang n8ng th8n, vbng Mu, vang xa, b d6 c6 the cho phep he

thong WiMAX phat veti deg suit cao han de giarn gig thanh then Mug he thong WiMAX VI voy, de nghj cho phep trier khai WiMAX trong bang tin 5,725-5,850GHz nhung WiMAX phiti clang chung bang tin vi phai bao ve cic he th6ng WiFi

Nhu vtly, vbi hien tang sil dvng bang tin tai Viet Nam nhu tren, cac bang tin c6 Icha Wing dinh cho WiMAX et Viet Nam la:

— Bang tin 2,3-2,4GHz vi 3,3-3,4GHz cho cic he thong truy c(ip kh8ng day bang rung, kg ea WiMAX

— Bang tin 5,725-5,850GHz cho cast he thOng truy cop kh8ng day bang rung, ke ca WiMAX nhung cic he th6ng nay phii clang chung bang tin yeti cic h>i thong

WiFi vOi dieu kien bao ve ctic he thong WiFi hog dOng trong bang tin nay

— Bang tin 2,5-2,690GHz cho cic he thong truy cop !thong day bang rung, kg

ca IMT-2000 va WiMAX

Chlnh phi da cep phep thu nghiem djch vp WiMAX di dOng tai bang tin 2,3-2,4 GHz vii bang tin 2,5-2,69 GHz (Theo deg van s6 55351VPCP-CN dm Van phemg Chinh phi)

1.4 Truyin song

Trong khi !lieu ding nghe hien dang tan tai cho !thong day bang rung chi c6 the

cung cep phi sang LOS, Gang nghe WiMAX ducrc toSi uu de cung cep phi sang

NLOS CEng nghe den den ctia WiMAX cung cap tat nhit cho ca hai Ca LOS vi

NLOS bj anh huong bei cic d#c tfnh dirbng truyen m8i tru&ng cis chimg, ten thit dutmg don, vi ngan guy' kit nhi v8 tuyen

Trong lien lac LOS, mOt tin hieu di qua mOt dirtmg Ulm tiep vi Ichong N tic nghen tir may phit din may thu MOt lien lac LOS yeu cau phin Ion mien Fresnel this nhAt thi kh8ng bj nein cim cis bit Id vet can nao, neu lieu chain nay ;thong thda man thi c6 sir thu nh6 ding ke cubng dO tin hien quan sit DO her Fresnel duct yeu ciu phu thuOc vao tin s6 hoM Ong vi Ichoing each gifts vi tri miy phit vi may thu

Trong lien lac NLOS, tin hieu den miy thu qua phin xa, tin xa, nhigu xa Cic tin hieu den may thu bao gam cac thanh phin hY dubng tnrc dip, cic dutmg duqc phim xp

nhieu lin, Wing luqng bj tin xa vi cic thrtmg truyen bj nhigu xa Cic tin hieu nay c6 Idioang trg khic nhau, suy hao, phan cvc vii dO on djnh quan hu vbi dubng truyen trim dip la nguyen nhan gay ra nhigu ISI vi mio tin hieu Dieu d6 !thong phai la van de deli ved LOS, nhung yeti NLOS thi Iai la van de chinh

Phan Tian Tang

Trang 10

TONG QUAN VE HE THONG WiMAX

C6 nhieu tru diem ma nhttng trier khai NLOS too ra ding khao !chit VI du, S yeu cau 1#p ke hooch chat the va giai Igut chiIu cao anten ma throng lcheong cho phdp anten duqc be trf cho LOS Vai nhOng Wen khai ti bao ke nhau phom vi rung, nai tin

s6 duce saf dtmg loi la tai hp, ha thip anten la thufm lqi de giim nhieu kenh chung girra tic vj trf cell lien ke Dieu nay thuang c6 tic dung fink day cic torn etc hoot dung trong cic dieu lden NLOS Cie he thong LOS khong the giam chi& cao anten

bai vi lam nhu vay se c6 tic dOng den throng quan sit Ulm tikp duqc yeu au tfr CPE

den tram geoc

Hinh 1.2 Minh hpa heat dong WiMAX

CEng nghe NLOS cfing giam phi ton cli at bang cich d#t dm% cic mai the that

bi CPE dimg nhu nguyen bin vl giant bat kh6 khan dinh vj tri cic dia diem at CPE thich hqp CEng nghe cang giam bat nhu ciu quan sit vj tri thiet bj phis truck vl cli

thien dt) chlnh xic ca a cic c8ng cu lop kg hooch NLOS

CEng nghe NLOS vl nhttng firth ning dupe Hang cao trong WiMAX to kha

nal% a* dung Net bj phis dau khich hang (CPE) trong nhl

1.4.1 Dien chi thich nghi

Dieu chi thich nghi cho phop he th6ng WiMAX dieu chinh so de diet' the tin

hieu phu thuOc Arlo diau kien SNR cart lien kit v8 tuyen Khi lien ket vo thy& chit

luqng cao, so de diets chi cao nhit duqc sfr dung, dua ra he thong dung luvng lan hon

BPSK SNR = 6dB, lbit/Hz QPSK

SNR = 9dB, 2bit/Hz 16QAM

SNR = 16 dB, 4 bit/Hz 64QAM

SNR = 22dB, 6 bit/Hz

Binh 1.3 B6n kinh cell quan hg vol dau chi thich nghi

Phan Tien Tang

Trang 11

Trong qua trinh suy gilun tin hieu, he thong WiMAX c6 the djch den mOt sa d6 dieu the thip han de duy tri chit lumg kot not vi On djnh lien ket Dac diem nay cho phep he thong !chic phuc fading Iva chqn than gian

1.4.2 Cling nghe spa 111

Cac c8ng nghe sat 161 di duqc hop nhit trong WiMAX de giant cac yeu ciu ti so

tin hieu ten tap am he thong Cac thuit Min FEC, ma has xoin vi chen duqc clang de phit hien vi sera cac lei cii thien thong lucmg Cac deg nghe suit 161 manh gulp khOi phuc cac khung bj lei ma c6 the bj mit do fading Iva chon tin so vi the lei cum Tv dung yeu ciu lap 1gi (ARQ) duce clang de sou lei mi Wong the duqc sou b61 FEC, gal

lei thong tin bj 161 Dieu nay c6 y nghia citi thien chit ltrqng tex de, 16i bit (BER) dei vii met mirc nguang nhu nhau

1.4.3 Dilu khan c8ng suit

Cic tit* toast dieu khien ding suit duqc dung do citi thief' chit luqng toan be he thong, no duqc thvc hien btri tram gic gni thong tin dieu ;chi& ding suit den mei CPE

de dieu chinh mtic c8ng suit truyin sao cho mire da Shen 6 train gic Oil 6 met mirc da xic djnh three Trong mei twang fading thay doi gong, mirc chi lieu da djnh truac nay c6 nghTa 11 CPE chi tuyen da ding suit they man yeu ciu ay Dieu khien deg suit gilun sv tieu thu Gong suit tong the cue CPE vi nhieu vii !tilting tram gee cling vi frt V6i LOS, c8ng suit truyin cos CPE gin timing ling vii khoang ctich mitt n6 den tram

g6c, vii NLOS, thy thuec nhieu vio dO ha vi vet can

1.4.4 Clic c8ng ngke v8 tuyin den din

a Ph& On thu va vhdt

Cic hrcrc de phan top duqc sir dung de lqi dung the tin hieu da duOng vi phitn xey ra trong cite mei twang NLOS Bing citch sir dung /fink Aug ten (truyen va/hoac nhon), fading, nhieu vi ten hao throng truyin c6 the duqc Mm giant Phan tap truyin sir dyng ma thin gian khung gian STC Doi vii phan tap nhan, cac citing nghe nhu kit hqp tjr le t6i da (MRC) mang 13i uu diem caa hai dtrimg thu rieng Wet Vi MISO (met diu ra nhieu diu vio) xem Error! Reference source not found.4

HIM 1.4 MISO

Phan Tien Tang

Trang 12

TONG QUAN VE He THONG WiMAX

M6 rung ten MIMO (xem Error! Reference source not found.5), sir clang MIMO cling se ning cao th8ng lucmg vl tang Mc throng tin hieu MIMO sti clang Wilk Ang ten thu vi/hoic phat cho ghep kenh theo kh8ng gian M61 Ang ten ce the truyen dtr lieu khac nhau ma sau de c6 the &roc gill ma 6 may thu Did v6i OFDMA, bed vi mai s6ng mang con la cac kenh bang hap Wong to, fading Iva chip tin s6 xuit hien nhu ll fading phing toi m6i s6ng mang Hieu (mg nay ce the sau d6 duqc m6 hlnh hOa nhuli mOt so khuech dpi thong d6i phtic hop vi c6 the don gian hes so thoc hien ctia met may thu MIMO cho OFDMA

HIM 1.5 MIMO

b Cdc he thane ant ten notch nig

AAS la met phi!' try chip Cie tram g6c c6 trung bj AAS c6 the tao ra cac chum

ml c6 the duqc Ili, tip trung Wing lucmg truyen de dat duqc pham vi lon hon Khi

nhin, cluing c6 the tip trung 6 liming co the mitt may thu Dieu nay gulp cho loci be nhiiu kh8ng mong mu& tt cite vi tri khlc

1.5 So slab WIMAX v6i WIFI vi 3G

Hien nay 6 Viet Nam cluing ta, WiFi vl 3G dang ll hai ding nghe kit nil kh8ng day phlt trien nhit nen ta c6 the so sanh chimg veri WiMAX

1.5.1 WiFi

WiFi - Wireless Fidelity la ten pi ml cite nhl san mit at cho mat chuin kit n6i khOng day(IFFE 802.11), cang nghe set dyng s6ng radio de thiet lip he thing kit n6i mang kh8ng day Day 11 deg nghe mang throe thuang mai h6a tien tier nhit hien nay WiFi vl WiMAX c6 cling mat nguyen hoot Ong 11 truy cep mpg qua tin hieu v8 tuyEn Kit nig WiFi nhanh nhit c6 the nu* duqc UM 54 Mbps trong cac dieu kien t6i uu WiMAX c6 the filly& len tell 70 Mbps, them chi khi bj chia tich gifta vai choc ding ty vl hang tram hO gia dinh ngubi dOng thi it Whit n6 se cung cip t6c dO tuang duang v6i t6c dO truyen con modem cap cho m61 ngubi dUng Nhtmg so Iduic nhau 16n

Whit gitra WiMAX vi WiFi khOng phii la tic dO truyin ma la ban lcinh phti song WiFi

Phan Tien Ting

c6 ban lcinh phu sling khan 30m con v6i WiMAX thl rung hen nhieu khoitng 50Km

Co ly tang la do tin so duqc stl dtmg vi cOng suit ctia may phat

Tuy vay, WiMAX duqc thiet ke khOng phiti de mau than voi WiFi ma de Gang

tin tai voi WiFi VOng plmi sang cua WiMAX duqc do theo 1Cm 2, trong khi yang pho song cua WiFi duqc do theo m2 Chuin WIMAX gee (IF.FE 802.16) de xuit vier su

chmg phi tin 10-66 GHz cho truyin din WIMAX, ma cao hen nhieu co ly WiFi (len tel tei da 5GHz) Nhung 802.16a da h6 trq them cho tin sto 2-11 GHz MOt tram glic WIMAX co the duqc truy cap btri han 60 ngatri su dung WIMAX ding c6 the cung

cap cac djch vu gang ba

Cac dile diem Id thuat WIMAX cOng cung cap the dieu kien thu$n lqi tot han nhieu so voi WiFi, cung cap dO rung bang tin cao han vi an ninh dit lieu cao bang cach sir dung cac ke hooch mil hOa tang cueng WIMAX cling co the cung cap djch vu theo ca hal dja diem LOS va NLOS, nhung co ly se thay doi cho phu hqp

WIMAX cho phep them nhap vac) dich vu bang ring Vol?, video, Ara truy cap internet ding thtri Ctic anten WIMAX c6 the "chia se" mOt thap cell ma khOng can den xep chirc niing cult the mang t6 ong dit ditch hqp

xu the hoti nhap filth mOt fieu chuin chung duy shit va phuc vu len den 2Mbps M#c

dh 3G duqc firth tam se la mOt chuin mang tinh town ciu nhung chi phi thy dung ca

so Ito tang cho he thong nay rat ton kern

b So stink WIMAX di &Ina viti 36

WCDMA duqc phitt trien de tang lchi niing dubng xuting voi phien bim truy nhlip goi throng xueng t6c du cao (HSDPA) va truy nh#p gel dubng len tec dO cao HSUPA Nhom phat trier 3G cOng can nhic phat hien khi niing truyen xa han cho WCDMA nhu la cung cap MEMO vOi HSPA

Tuang to nhu stay, CDMA 2000 ducat ph& train de tang Ichit rang truyen din se lieu tai phi& ban lx EVDO-Rev 0 Ara lx EVDO-Rev A MOt clang cao nits la phi& ban EVDO Rev B Qua vtio khit niing da song mang

Phan Tien Tang

Trang 14

Tieu chuin ca sec

32 Mbps, DL/UL=1 TOc du dinh UL 1,8 Mbps 5,8 Mbps 7 Mbps, DL/UL=1

4 Mb s s, DL/UL=3 H-ARQ

D c ng b0 4 kenh nhanh IR

TONG QUAN VE He THONG WiMAX

Do 1xEVDO va HSDPA/HSPA dupe phit then ter tieu chitin CDMA 3G de cung

cep djch vp s6 lieu thong qua mang ban diu duce thiet ke cho djch vu thoai di dung do

d6 no thus huOng ca nhftng uu diem va ca nhOng han the cult he thong 3G WiMAX

ban du dirge phit then cho truy nh$p v6 tuyin bang rang co djnh va ne dirge ten tru

cho truyen s6 lieu WiMAX di dung throe phit trien tren ca so cis WiMAX co djnh va

duce diet' chinh a phi\ hap cho yeu cau di dOng Viec so sinh gifta cic thuac tinh cis

WiMAX di dung vOi 3G tren ca so he thong lx EVDO va HSDPA/HDPA se cho to

they r5 cong nghe nao se dip Ong throe cic did hai cis mang djch vu s6 lieu bang rang

di dung Cac thuOc tfnh cu the dirge dua ra trong bang 1.2

Bang 1.2 So sdnh Ws:MAX di Ong vie 3G

Phan Tien Tang

Trang 15

1.6 Kit luen chuvng

Qua tim hieu nhDng phan trinh btly 6 tren glop to ce mOt cal !thin ten quan ye deg nghe Wimax, so sixth veri cac yang nghe 'thong day lchic, dua ra uu, nhuqc diem, Idia Ming (mg dung va filth hInh trim lchai caa n6 trong thqc 4 Tu d6 di bit diu di du han, tim hieu ye bin true mang truy cep WiMAX se duqc tr1nh bay 6 chuong tiep then

Phan Tien Tang

CAC KT THUAT Sir DUNG TRONG WiMAX

CHMING 2: CAC KT THUAT SlY DUNG TRONG WiMAX

2.1 Ky thuet OFDM

2.1.1 Sir dnh Mang cia nail truing din Wee tn(yIn den

Thir !that to phii khing djnh ring mai trueng truyin thong v8 tuyen 16 mOt m6i throng khic nghiet nhit trong truyen din th8ng tin N6 gay suy hao tin hieu ve bien dO cOng nhu suy hao lira chon tin s6 kern theo cgc hieu ting fading da throng

Sr suy hao tin hieu tang nhanh theo khoitng each vi 6 tin s6 cao, ngotli ra ser suy hao ding phv thuOc vtlo dia hlnh (khu vvc n8ng th8n, thinh thj, ding bing hay mien Hinh ve duck dAy mink hoa sty suy gum tin hieu theo khoing each vi tren cac loci dja hlnh veri cac dieu kien truyen din Ithic nhau ctia hai he thing ISM tin s6 2,4 GHz vi UNII tin s6 5,4 GHz

Hinh 2.1 Suy gitim tin hieu theo khodng catch

Ngoli ra trong m8i truong truyen din da duong, nhieu xuyen ky ter (ISI) gay Uri

tin hieu phin xa ce thee gian tre !chic nhau th cdc hueng lchic nhau ter nai phat teri nal thu 11 dieu Wing the tranh khOi Anh holing nay co the ibm bien ding tin hieu lchien ben thu kh8ng the kh8i phvc dtrqc tin hieu

2.1.2 Da song mang (Multicarrier)

Neu truyen tin hieu khong phii bang mOt song mang and bing nhieu sang mang,

m& song mang tai mOt phin &Et lieu c6 ich vi duqc triti deu tren cit bang thong thl khi chju Anh hutmg Au se chi c6 mOt phin dft lieu cat ich bj mkt, dva tren co set der lieu

ctla cac sting mang khac c6 the khei phvc lai de lieu c6 ich

Phan Tien TAng

Binh 2.2 Sy tgo ra tin hieu OFDM

Do vey, khi ding nhieu song mang c6 tdc dO bit thep, nhieu clit lieu g6c sE duqc thu chinh xic Di hei phuc der lieu di mit, ngubi to ding phuong phip sfra lgi FEC- Forward Error Correction t3 may thu m6i song mang duqc tech ra khi ding cic b0 loc th8ng thubng vtl gill dieu chi Tuy nhien di kh8ng c6 can nhigu gills cic sting mang (ICI) can phii co khoing ha° ye khi hieu qui 06 kern

11•1•411.1

A A

HIM : PDM thong etas vi CIPDM

Binh 2.3 FDM thong finding va OFDM

Gill phip lchic phuc viec hieu qui ph6 kern khi ce lchoing bio ve (GUARD PERIOD) la giant khoing cich cic song mang vi cho phep ph8 cis cic song mang canh nhau trUng nhau Su Ding lep nay 11 duvc phep nen khoing cach Watt cic sting mang dtroc chcm chinh xic Khoing cich nay thrqc chon ung vai trubng hop cic sting mang true giao vOi nhau DO 111 phuang phip ghep kenh theo tin so tnrc giao (OFDM) Cho tel nay dull tren nhttng thanh tuu cis c8ng nghe mach deb hop phuong phip nay dit duce thuc hien met cich d8 clang

Phan Tien Tang

CAC KT THUAT Sfi DUNG TRONG WiMAX

2.1.3 Cling nghe OFDM v61 lad ndng hon chi nhilu

WIMAX se dung c8ng nghe OFDM de Irwin du lieu 6 giao dien vo tuyin va

cho ph6p the thug bao troy nh$p kenh Cling c6 nhieu deg nghe ;chic 6 giao Bien nay

nhu FDM, CDMA Tuy nhien OFDM da chting to n6 co nhftng uu diem han rat nhiiu

va t6c dO truyen, tS, le 16i bit, ding nhu hieu qua se dung ph6 tin nen de duqc IFPF chqn lam Ong nghe truyin din cho truyen din vet tuyen bang rung trong chain IEEE.802.16

Cac ki thu#t se dung trii ph6 true tiep DS-CDMA nhu trong chain 802.11b rat d6 bi inh hu?mg Uri nhilu da dueing vi thbi gian tr6 c6 the vuqt qua kholing thtri gian ctia mOt Id tu OFDM se dung ki thult truyen song song 'Neu bang tin con nen kdo did th6i gian truyen ld to len nhiiu lin Ngoli ra OFDM can chen them mOt khan bao ve GI (Gaurd Interval) thu&ng 16n han tit gian tri t6i da cart kenh truyin gills 2

Id AT nen nit& ISI c6 the duqc loai bo hoan twin

Tren kenh truyen din MI Mau lea chqn tin s6 cling le mOt van de anh Ming len den chit luqng truyen thong tin hieu Tuy v$y OFDM ceng rat mem deo va linh hoot khi giiti guy& yin de nay OFDM as the khed phut lei kenh truyen thong qua tfn hieu din duang (Pilot) duqc truyin di cling yeti clang tin hieu th8ng tin Ngoli ra yeti cite kenh con suy gilun nghiem treing ye tin s6 thl OFDM can cob mOt Iva chip nett de giam tSr 1016i bit la gam bat s6 bit ma h6a cho mOt tin hieu dieu the tai kenh tin so d6

Binh 2.4 So sdnh song mang mkt OFDM vol ctic hinh that

truyin thing

1-11nh teen so sanh gifts hai hinh thee dilu che D6i yeti clic hinh thin truyin thong, mOt song mang dan veri bang th8ng rung se duqc truyen di, trong khi v6i OFDM bang thong rung nay duqc chia that:1h cac bang con, mil bang con se img vol Phan Tien T(Ing

mOt sing mang con, cic sing mang con trvc giao nhau Viec chia bang con niy se litm t6c dO tren mai bang con nay gitim di N lin, tuy nhien, chu Id cis mOt sang mang cling

se dii hon N lin Dieu niy giop cho viec ding b0 a ding hon, trinh nhigu da dubng cling tot hon Viec chia th8ng tin cang glop cho viec chong nhigu tat han, vi niu bj

nhigu, Ong chi bj nhigu ten cite cum don le, nen ce the khic phuc a ding han

Mai sting mang duqc gain luting dit lieu de truyin di Bien dO via pha cos sing mang duqc tinh toan dva tren phuang thin dieu the (thubng li QPSK, BPSK, QAM) Sau d6 ding bien doi IFFT (Inverse Fast Fourier Tranform) di bign tir mien tin s6 ve

mien thtri gian IFFT li mOt phucmg phip toles dhi hieu qui vi dim bio cho cic sing mang con trvc giao Tai b0 nhan, nortri to ding Bien doi FFT(Fast Fourier Tranform)

de bien d6i nguqc 13i tir mien thbi gian sang mien tan so

MOt van de quan tong trong truyen din li sv dbi hei !chit khe ve sv (long b0 vi

sv sai lech vi tin s6, Anti hulk% cult hieu (mg Doppler khi di chuyen vi lech pha se gay ra nhigu giao thoa tin so ICI (Intercarrier Interfrence) mi hau qui la phi be sv trvc giao gifts cic tin so sting mang vi lam tang anh huing tai he tilting cling nhu BER Tuy nhien OFDM cling c6 the giim bat sv phtic tap colt van de ding b0 thong qua khoing bio ve GI Viec su dung chu8i GI cho phep OFDM co the diet' chinh tin s6 thich hop mac di viec them GI cling ding nghia vai viec gian hieu qui so dung bang tin

Binh 2.5 OFDM phtit va thu

BO Serial to Para djnh d?ng luting der lieu, nhim cic bit l.i de gain cho cic sing mang (VI du se Whim 6 bit mOt nhim lieu li QAM64)

Phan Tien Tang

CAC KY THUAT SIT DUNG TRONG WiMAX

OFDM hi mOt ding nghe chia TIM bang tan thlnh de bang nhe hon.Trong WIMAX

then chuan 802.16d, dit ap dung ding nghe ntly VI v(ty WIMAX fixed c6 the host dOng

duqc trong m8i twang NLOS (Non Light of Sight) Trong WIMAX fixed dirge chia

dui& 256 sang mang con, 19811 danh cho de lieu, con lai dinh cho Hwang &to ve

2.1.4 Teo va thu OFDM

Tin hi./ OFDM bong g6c (basebend) D/A

RECEIVER

Hinh 2.6 Su lid kai can thiit bi delu culla

Phin may phat bien dui dtt lieu s6 din truyen, Anti vbo bien clO vb pha cult ck

tai phu Sau d6 n6 bien d6i bieu dien ph6 cua dtt lieu vbo trong mien thoi gian nha sfr

dung hien d6i fourier ran rac deo (inverse Discrecte Fourier Transform) Bien al

nhanh Fourier deo (Inverse Fast fourier Transform) thud hien cUng mOt thirst tofin Whir

IDTF, ngoai trfr ring n6 tlnh hieu qua hon nhieu vb do vay n6 dirge sir dung trong tit

eft cite he thong thud te De truyin tin hieu OFDM tin hieu mien thei gian doge tinh

toan phlich len tin s6 an thiet May thu thirc hien thirst tom nguqc lai vii may phat

Khi djch tin hieu RF xu6ng bang ca se de xi 1St, sau de sir dung bien d6i Fourier

nhanh de phan tich tin hieu tong mien tin s6 Sau de bien 40 vi pha cult et di phu

dirge chip ra vb doge bien d6i ngugc lai thanh dit lieu so

2.1.5 Clic se di min chi

Dtt lieu s6 dirge truyen tong kit nisi OFDM bang each dung so d6 dieu chi ten

mai tai phu Sa d6 dieu the lb sir Anti xu the clii lieu vbo chum sao thgc (d6ng pha) vb

phfrc (vuong pha), duqc biet nhu chum sao IQ (inphase Quadrature) SO bit c6 the

doge truyin khi dung mOt symbol tuong fmg vii log2(M) vii M lb s6 the diem trong

chom sao M6i to clit lieu dirge dnh n vbo mOt vi tri IQ duy Whit tong chom sao

Vecta phfrc hqp thanh I +jQ Wang fmg vii hien dO 4/2 vb pha argument (I+ jQ)

Vic tang s6 diem tong chum sao khong thay d6i dai thong truyen, do vity

vied dung so d6 dieu she yeti !Neu diem chom sao se cho phep citi thien hieu quit phis

(hose hieu suit bang thong) Tuy ninon, s6 diem tong gian d6 chem sao cang 16n bao

Phan Tien Tang

nhieu Oil viec gild guy& ch(mg 6 may thu cang kh6 bey nhieu D6 la vi !chi de cat vj td

IQ duqc tang gin nhau nen chi chn mOt gia tri nhe nhieu 11 c6 the gay ra 16i truyen

MA Gray:

Gifin d6 IQ cho so d8 (lieu the chi m vecta truyen cho tit ca cac lien hqp tCr dli lieu Mgi lien hqp tir dtt lieu phid duqc phis phei mOt vecta IQ duy Sits MA Gray la mOt phuong phi') cho su phiin phdi nay, sao cho cat diem conh nhau trong yam sao chi lank nhau mOt bit dan MA nay giup gam thieu d le l6i bit MA Gray ce the duqc

ml dung cho tit ca cat so d6 dieu the PSK (BPSK, QPSK, ) va QAM (16QAM, 64QAM, 256QAM )

Decimal Gray Coding

Phan Tien Tang

CAC K! THUAT STY DUNG TRONG WiMAX

C6 the giant tut huerng ISI tOi tin hieu OFDM bang cich them Arlo cic kho ing bio ve 6 truck cua m6i symbol Khoing bio ve tuly la bin copy tan hoin theo chu ky, lam ma rang chi& dii cua don sang symbol NO duqc tao ra bing cach lay plan cutSi

dm symbol OFDM de dua vac) pit du Do vay viec dua Arlo cic bin copy cult symbol noi duoi nhau tao thinh mOt tin hieu lien tac, Wog c6 stir elm (loan ey ch8 n6i Nhu vay viec sao chop du cuoi cua symbol di tao ra mat khoitng thiri gian symbol dii han va giii dieu the n6 mi Ichong c6

sYna 1

Kt lieu IN) N-1 Kt Mu Mar N Kt Wu the N•1

Binh 2.8 Chen khoong that gian bao Are cho mai ky hieu

2 L 7 Too cdc hiss OFDM

MOt 1E9 hieu OFDM bang tan g6c c6 the duqc tact ra trong mien so tru6c khi duce dieu the vac) cic sang mang con de truyen din De tao ra mat OFDM bang tan g6c, mOt luang dit lieu di duqc s6 has trutc tien duqc thiu the stY clang cic m8 hinh dieu the chung nhu PSK hottc QAM Sau do, nhing ky hieu dO lieu nay duqc chuyen n6i flap thanh song song truck khi that hieu dieu the cic sang mang con Cac sang mang con duqc lay mitt veri t6c da N/T„ veri N la s6 sang mang con Ara T, 11 Ichoting than gian ky hieu OFDM, khan); tan se gifts hai sang mang con Ice can la 2II/N Cu6i ding tilting matt tren m6i sang mang con duqc tang hqp lai thanh mOt miu OFDM Mat 1c9 hieu OFDM duqc tao ra b6i mat he thong OFDM c6 N song mang con gam N miu va miu tit* m cua mOt1c9 hieu OFDM

truyen den deu thu Trong mien tin s6, dip img niy II de chuyen du tit ci nhttng sang mang tir Wing tin g6c deng thiri len tin s6 sang mang Hinh 2.9 cho they mOt bO phit OFDM gem 4 song mang con vi qui trinh tao ra mOtIcS , hieu OFDM

Chu& bit

Binh 2.9 B6 phat OFDM 4 song mang 2.1.8 M8 td kfi hieu OFDM

a Man then plan

Sang OFDM duqc tao ra nho Bien &Si Fourier ngtrqc, Ichoing then gian niy dtrqc xem nhu IA Ichoing th&i gian co ich mkt icsr hieu Tb Bin sao cis chu Id k, hieu c6 ich cu6i citing Tg, ductc g9i lk den t6 min hoin CP, duce sfr dung de hieu qui han tong tip hqp da dutmg, trong khi yen duy tri tfnh trqc giao cia cic song mang con Hlnh 2.10 bieu clan du frac icsr hieu OFDM trong mien thin gian

Binh 2.11 M6 td tan so OFDM

Phan Tien Ting

rimpaa-

s gas

111.8011a adiermis 00101 Wet U tea

yob* rtheref01011101ale

CAC KT THUAT SLY DUNG TRONG WiMAX

LOp vet lg mks WirelessMAN-OFDM lit (km veto di& cho OFDM Dft lieu duqc gfri trong khung mia cic hieu OFDM MOt kg hieu OFDM duqc Mo ra ter cic song mang vi ce FFT duqc xic djnh bai s6 song mang CO 3 loci sting mang duqc se dung

6 clay:

— Cic song mang dit lieu (DC): cho fruyin din dft

— Cic song mang hoa tieu: cho cic raw dfch trot tinh Mac nhau

— Cic song mang khung gii trj (Null): khung truyen din tit ci, duqc dung cho cic dii bio ye vi cic sang mang DC

Muc dich cda cac dii bato ye la cho phtp tin hieu suy giitm vi tao clang "tubng gach" (Brick Wall) FFT NO ding g6p phin xoi be giao thoa gifts cic kenh

2.1.9 aunt khung

MOt khung duqc chia &AM cic khung nhe DL vi UL Nhfitg khung nhe DL vi

UL duqc bit dim voi 8 preamble (cho blot gioi han s6 song mang mkt symbol) de tim lai thong tin ve kenh truyen vi cho phip may thu tlm lai dip ting kenh O FCH vit DL MAP chira thong tin ye nOi dung khung (vi trf vi kieu dieu cho cOtt m8i burst) vi duqc dieu the - BPSK

Hinh 2.12 Cdu trek khung 802.16 OFDM

2.2 KT thu$t OFDMA cho mpg WIMAX

OFDM khai thic phin tip tin s6 caa kenh da duerng bei ma hod vi dan xen th8ng tin qua sting mang con truOc khi truyen din Dieu chi OFDM co the duqc that hien hieu qui vei bien tt61 Fourrier nguqc nhanh (IFFT), mil cho phop mOt s6 luqng 16n song mang con (len tai 2048) v6i dO phitc tap thip Trong mOt he th6ng OFDM, tili nguyen khit dung trong mien then gian la cic hieu OFDM vi trong mien tin s6 la cic sting mang con Cic tai nguyen thbi gian vil tin s6 c6 the duqc sip xep thrinh cic kenh con de oip phit cho tong nguei so dung Da truy nhip ghop kenh phan chia theo tin so trim giao (OFDMA) la mOt ke hoach ghip kenh da truy nh$p de cung cip hoar Phan Tien Ting

dOng ghdp kenh ens luting dtt lieu tir nhilu ngubi su dtmg tren cac kenh con throng xu6ng vi da truy nhip doting len Uri cac kenh con dutmg len Nhitu ngubi dung cling chia se met bang tin nin duqc goi IA OFDMA Mgi ngubi dung c6 the dtng met so sting mang con da djnh truck hoc thay del toy theo thong tin can truyen (str diiu khien nay phi thuOc vao lap MAC)

Cong nghe OFDMA cho phep nhang sang mang con duqc gin Ufa cac ngubi dung Ichac nhau VI dv cac sang mang con 1, 3 va 7 c6 the duqc gin cho ngubi dung 1,

va cac sting mang con 2, 5 va 9 cho ngubi dung 2 Nfring nhom sang mang con My c6 the duqc xem nhu cac kenh con OFDMA cho phep kich thuOc FFT nhe hcm de di thien chili luqng dhi yeti cac kenh c6 giai thong thip ham

Trong Wi-Fi thi tat ca cac tram deu truy nh$p met each ngiu nhien den diem truy cep AP, vi vey m8 khoang each khac nhau to mai nut den AP se lim giam thong luqng cua mang Nhung b 16p MAC ctla 802.16 thi qua trInh truy nhip cua mai thus bao la duqc djnh twat vi v(ty cac tram chi c6 duy nhit met len cash tranh kenh truyin din la thei diem m fillip mpg Sau mai thai diem de thi mai tram dirge tram goc gin cho met khe thbi gian, khe thin gian d6 c6 the me rOng hay co hgp lai trong qua trinh truyen din

4

frequency

User A • Uwe • Um C 1111 User D

Hinh 2.13 Sr sap xip theo hai chau trong OFDMA 2.2.2 Malin qc 111th vuvt

Uu diem ctia viec det sin lich trinh nay la viec truyen din van hoot ttOng met each

On djnh trong tnrtmg hqp qua tai vi s6 luqng thug bao ding IcSr vuqt qua cho phdp lam

Phan Tien Tang

CAC KT THUAT SIT DUNG TRONG WiMAX

tang kha !tang sir dung bang tin Ngoai ra, n6 con cho phdp tn;un g6c c6 the dieu Ichien

chit luong djch vµ (QoS) bang viec can bang nhu cau truyin thong gifts cric thud bao

Clic qua trinh de ducm thus hien bei viec raft hen va ditu the thich nghi AMC

(Adaptation Modulation and Coding) di ttoi uu h6a bang thong tujr thuOc vio dieu kien

cfmt kenh truyen Veri kenh truyin tot cc!) the dieu chi clang 64-QAM Veri kenh truyin

chit loong thip hon thl dung dieu chi QPSK

KT thu$t AMC la mat trong nhftng uu diem 16n ctia OFDM vi n6 cho phdp tai uu

Ma raw dilu chi tren m6i kenh con dva tit chit Wong ctia tin hieu (SNR) vi chat

ltrong cibt kenh truyin din Vii OFDMA n6 cho phdp viec phan chia tai nguyen cho

cgc thud bao thong qua viec truy nh$p vio eic sting mang phv khic nhau

EZE fl

OFDM

Hinh 2.14 Sit so stink OFDMva OFDM

Bang 2.2 Tam so vat 13, cua OFDM

a Phan hoa kink con

Trong wimax, clic user duqc clip clic khai sting mang con hon 11 cic song mang

con riling biet di giltm str phirc tap cho thu$t than cung clip sting mang con vi lrbn don

viec anh xa cfic ban tin Gilt sub rang mOt user k duce cap mat khoi 1.ek cic song

Phan Tien Tang

mang con, cac seng mang con nay c6 the duqc phlin b6 tren toin bang thong theo m8 hlnh sip zip song mang con phan ph6i, hoac cling met day ten se theo me hlnh sip xip seng mang con ke can U'u diem cult m8 hlnh sip xip s6ng mang con phan ph6i la tang firth da clang vi mph me ciut bang thong, uu diem cult m8 hinh sip xip song mang con ke dip la tang unit da dang cult nhieu user

b Sty ink xa cdc bin tin

De cho in6i MS Net la nhftng sang mang con nao duqc diet cho n6, BS phat quing ba thong tin nay trong cac ban tin DL MAP, cling nhu BS cho mei MS biet nhftng sang mang con nio cho n6 buy& ben tin UL MAP Ngoii viec cap cac song mang con taw& thong UL vi DL cho MS thi MS cling phai hieu cac burst profile duqc se dvng cho UL vi DL Burst profile dva tren viec do S1NR vi BLER cho ca hai dating vi nhan dang mirc dO thfch img cult sv ma hoa vi dieu cht

c Ste sin xiip

Khi in& MS xac djnh khoing each den BS, n6 guy& djnh sv deng bO Slc9 hieu

vi can bang mirc c8ng suit thu gift cac MS, qui trinh nay duqc gqi 11 sv sip xep Khi khoi diu, viec sip xep yeu au BS du doin dO mph cea kenh vi thbi gian den cos

MS Sv deng bO doing xuing thi khong cin thiet khi dutmg nay luon duqc clang bO trubc Nhung tong dutmg len, cac user can duqc deng be tii thieu tong met chu ky kholtng thin gian chin Neu !thong thi nhigu xuyen 1E9 tlr vi nhigu gifra cac song mang

se xiy ra Tucmg tv, thong qua dieu kid& dog suit duerng xuing duqc you ciu a

gilun sv can nhigu qua cell lchic Dieu khien c8ng suit dutmg len dg tang thbi gian seng cua pin vi giam xuyen nhigu gifts cac cell

Trong wimax gem c6 4 loci thu tvc sip xip: Wien um, khan chu kt, you citu bang thong vi chuyen giao Sip x6p duqc thvc hien tong 2 hoac 4 1c9 tv lien tvc mi lchong c6 sv kit hqp pha, dieu nay cho phi p BS biet mOt MS da mit &mg be, mat kit n6i djnh thbi rung hon so WA den t6 yang Neu the tvc sip zap thinh c8ng BS gfrl mOt bitn tin dap ling sip zip di chi thi MS (lieu chinh thin gian offset thich (mg, lam dung ten s6 offset vi duet lap c8ng suit Neu sip zip kh8ng thinh c8ng, MS se tang mac ding suit vi mOt bin tin sip xip mai de tiep tvc qua trinh nay den khi thinh dog

2.2.4 du true ki bleu OFDMA va phin kink con

Citu tree k9 hieu OFDMA g6m c6 3 loai song mang con nhu trong hlnh 2.15:

— Song mang con cat lieu de truyin din da

— Song mang con hoa tieu cho mvc dich &cc tinh vi deg be

Phan Tien Tang

0 0 0 0 0 0 0 0 0 0 0 0 0 0 Cie kl hiW chin

0

• 86ng arm mei Nu Sting wow eon ha Mu

CAC K1 THUAT Sti DUNG TRONG WiMAX

— Song mang con Null khong clang cho truyen din, m8 sir dung cho cac dii bao

ve va cac song mang DC

Cac song mang con tich cuc (de lieu vd hoa lieu) duqc nhOm thenh cac tap con goi la cac kenh con Lop vet 19 OFDMA 802.16e h6 trq kenh con trong ca DL vi UL Don vi tii nguyen thiri gian - tin s6 nheo nhit ctia pit kenh con la mOt lche bing 48 tone dO lieu (song mang con) CO hai loci holm vi song mang con phan cho kenh con, phan t$p Ara lien Ice Holm vi phin t$p duo cac song mang con gii ngiu nhien vio clong mOt kenh con NO cung cap phan t$p tin s6 vi trung blinh hob nit& gifts cric to brio Cac hoan vj phan t$p bao ghm DL FUSC (sting mang con duqc se dung hit tom),

DL PUSC (song mang con duqc se dung mOt phin), UL PUSC vi cac holm vj khong bit buOc

sent, mono hoar

t

t ttttt

Song ming S oon MD

ttftt

HIM 2.15 Chu truc song mang con OFDMA

V6i DL PUSC mai cap ky hieu OFDM, cdc song mang con !chit dung hoac thich hop duqc !them thanh cdc gun bao gam 14 sting mang con lien ke tren mOt chu ki ky hieu, ce cep phat hoa fieu vi de lieu 6 mai cum trong cac ky hieu le va chin duqc bieu di& nhu trong hinh 2.16

H'inh 2.16 Kenh con pht2n kip an se DL

Ke hooch sip xep isi duqc se dung de nhom cite cum sao cho mai nhom duqc ciu thinh t>Y cac cum duqc ph8n b6 lchip khong gian song mang con MOt kenh con trong mOt them g6m hai cum va ducrc cAu thbnh te 48 sting mang con de lieu, 8 sting mang con hoa lieu Cac song mang con de lieu trong mai !them duce holm vj di to m cac kenh con trong nhom VI wcsty, chi cac vi tri hoa fieu trong cum duqc bieu diin Phan Tien Tang

trong hinh 2.15 Cie s6ng mang con d& lieu trong cum dirge phin b6 cho nhieu kenh

con

Tuong tv vei ctiu true cum DL, mOt ciu frac tile duple djnh nghia cho UL PUSC

c6 clang nhu hlnh 2.17

Khong gian song mang con khi dung dugc chia thinh cic file vi 6 tile doge chern

qua thin bO ph6 bei ke hooch hoin vi/sip xep lei, dune nhem lai de hlnh thinh mOt Idle Khe gam c6 48 song mang con (Kt lieu vi 24 song mang con hoa lieu trong 3 Iccr hieu OFDM

Hoin vj lien ke nh6m mOt kh6i cic s6ng mang con lien ke de hlnh thinh mOt kenh con hoin vi lien ke bao g6m DL AMC, UL AMC vi c6 clu true tircmg to MOt bin g6m 9 s6ng mang con lien kb trong mOt kjr hieu, vOi 8 gin cho dtt lieu vi 1 grin

cho hoa tieu MOt khe trong AMC doge djnh nghia Mir mOt top hqp cic bin cria kieu

(NxM=6), trong de N 11 s6 bin lien ke vi M li s6 kjr hieu lien kg VI vay, cic t6 hqp doge phdp li [(6 bin, 1 kS, hieu), (3 bin, 2 14 hieu), (2 bin, 3 kjr hieu), (1 bin, 6 14 hieu)] Hoin vj AMC cho phdp phial t$p da ngtrai stl dung Mei Iva chein kenh con co dip Cmg tin s6 tot nhit

Song mono con 00 Ilfou

Hinh 2.17 Cciu Thic tile cho UL PUSC

Nhln Chung, phin t$p twin vj s6ng mang con thvc hien tot trong Mc ring dung di dung con hoin vj s6ng mang con lien kb phil hqp trong the m8i trutng cti djnh ho#c tinh di dOng thtip Cic sv lip cheen My cho phep nhi thiet Ice he thong can bang tinh di Ong cho thong luring

2.2.5 Clu trac khung TIMI

PHY 802.16e h6 trg TDD, host gong FDD song c8ng vi ban song Gang Tuy Mien, phien bin ban diu mkt 802.16e chi bao g6m TDD V6i the phien ban sau My, FDD duqc xem )(et ben dign din WiMAX bin vi cic co hOi thi trutmg d#c biet 11 cic yeu caw dieu chinh ph6 nOi hat hoac ngAn chOn TDD ho#c phA hgp cho viec tan khai FDD De chang lai nhigu, TDD yeu du (long bO toin he thong Tuy nhien, TDD II m8 hinh song Ong thich hgp hon vi cic If do sau ay:

Phan Tien T#ng