BO GIAO DI C VA DAC , TAO
TWANG 13$1 HQC THONG LONG
---o0o---
KHOA LUAN TOT NGHIEP
TIM HIEU VA NGHIEN °UV M4NG
KHONG DAY VVIMAX
Ciao vien hirerng chin : Mani Thanh Giang
Sinh vien thvc hien : Tan Thai Linh
: a13520
Ma sinh vien
: CONG NCH*. THONG TIN
Chuyen nghanh
HA NQI - 2013
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MUC LUC
CHUONG 1. GIOI THI$U CHUNG VE WiMAX
1
1.1. GIOI THI$U CHUONG
1
1.2. MAI NIEM
1
1.3. CAC CHUAN CUA WiMAX
4
1.3.1. Chuan IEEE 802.16 - 2001
4
1.3.2. Chan IEEE 802.16a
4
1.3.3. Chuin IEEE 802.16 - 2004
5
1.3.4. Chuan IEEE 802.16e
5
1.4. P116 WiMAX
7
1.4.1. Bang tat' ding k9
7
1.4.2. Bang tin khong dAng k9 5GHz
8
1.5. TRUYEN SONG
8
1.6. UV DIEM VA NHUM DIEM COA CONG NGHE WiMAX
10
1.7. TiNH HiNH TRIEN KHAI WiMAX
13
1.7.1. rmh hinh trien khai WiMAX tren the glen
13
1.7.2. Tinh hinh trien khai WiMAX this nghiem tai Viet Nam
13
1.8. KET LUAN CHUONG
14
CHUONG 2. CAC KV THUAT MAX SlY DUNG THONG WiMAX
15
2.1. GIOI TH1EU CHUONG
15
2.2. Kt THUAT OFDM
16
2.2.1. Khai niem
16
2.2.2. So dó khOi OFDM
17
2.2.3. ChuOi bao ye trong he thong OFDM
18
2.2.4. Nguyen tic giai dieu the OFDM
19
2.2.5. Cac uu vi nhtrqc diem cita ki thuit OFDM
19
2.3. Kt THUAT OFDMA
21
2.3.1. IChai niem
21
2.3.2. Dec diem
22
2.3.3. OFDMA nhay rim
23
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2.3.4. He thong OFDMA
25
2.4. Dieu the thich nghi
26
2.5. Cling nghe sin 16i
27
2.6. Dieu khien c8ng suit
27
2.7. Cac ding nghe anten tien tiAn
27
2.7.1. Phan tip thu va phit
27
2.7.2. Cic he thOng anten thich nghi
2.8. KET LUAN CHUONG
CHUONG 3. MEN TRIJC MANG TRUY CAP WIMAX
28
29
30
3.1. Gist THIEU CHUONG
30
3.2. MO HINH THAM CHIEU
30
3.3. LOP DIEU KHIEN TRUY NHAFIMOI TRUONG (MAC)
32
3.3.1. Ket not vi dja chi
32
3.3.2. Lop con hOi ta MAC
34
3.3.3. Lop con phin chung MAC
34
3.3.4. Ca the yeu au vi cap Oat bang th8ng
38
3.3.5. Co the
40
lich djch va vi chit Itrong djch v0 (QoS)
3.4. LOP VAT Lt
42
3.5. KET LUAN CHUONG
44
CHUONG 4. MO PHONG HO/ST HONG 14 THONG WiMAX
45
4.1. GO! THIEU CHUONG
45
4.2. MOI TRUONG MO PHONG
45
4.3. MO PHONG
47
4.3.1. Gia thuyet
47
4.3.2. Kjch bin mo phong
47
4.4. PHAN T1CH KET QUA MO PHONG
50
4.4.1. Holt dOng
50
4.4.2. Tinh lunng bring th8ng dirqc s* dung ten cic Node
51
4.5. NHAIsIXET
56
KET LUAN VA MANG PHAT TRIEN DE TAI
57
TAI LIEU THAM KHAO
58
Phv Ivc A: Gil trj truirng Type trong thong blo quin trj lop MAC
59
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MVC LUC HIM! VE
Hinh 1.1. Minh hos hoot dOng WiMAX [10]
9
Hinh 1.2. Truyen sling trong tnrang hop NLOS [10]
10
Hinh 2.1. So sanh gift FDMA va OFDM
16
Hinh 2.2. Sa d6 khoi he th6ng OFDM
17
Hinh 2.3. Khai niem ve chu6i bito vg.
18
Hinh 2.4. ISI va cyclic prefix
19
Hinh 3.1. MO hinh them chieu [5]
30
Hinh 3.2. Chile nang ck lap trong m8 hinh phan lop chart IEEE 802.16
31
Hinh 3.3. Luling der lieu qua each!,
31
Hinh 3.4. Djnh dung MAC PDU
35
Hinh 3.5. Djnh dung cua tieu de MAC PDU chung
36
Hinh 3.6. Djnh dung tieu de yeu cau diti thong
37
Filth 4.1. Module WiMAX trong kien true NS-2 [13]
46
Hinh 4.2. MO hinh mung m8 phong
48
Hinh 4.3. Lien ket giOn MS va cac BS
51
Hinh 4.4. Mac nang luong giera 2 cell
51
Hinh 4.5. Ck tratmg event trong file barn vet —.tr
52
Hinh 4.6. Ck trutmg trong Wireless Event
53
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MUC LVC BANG
Bang 1.1. Tom tit ck dac thing ca ban dm chutur WiMAX[6]
7
Bang 3.1. Cac trtdmg tier' de MAC chung
37
Bang 3.2. Cac trtrOng tieu de MAC you cau diti thong
38
Bang 3.3. Dac to vat!), char' IEEE 802.16
42
Bang 4.1. KM qua thei gian chuyen giao cita MS.
55
MVC LVC BIEU De)
Bleu 6 4.1. Thong Itrong SS khi MN di chuyen veri ttic dO 1 m/s
54
Bieu 6 4.2. Thong luong SS khi MN di chuyen vai t6c do 4.147 m/s
54
Bieu 6 4.3. Thong luong SS khi MN di chuyen v6i tin dO 8.3 m/s
55
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P HV LVC
Phu luc A: Gia tri trtrOng Type trong thong bio quitn try' lop MAC.
Phu luc B: Giao thin djnh tuyen DSDV.
Phu lye C: Cal rig NS-2 tren nen Ubuntu 12.04.
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Danh myc thy& ngti va cac tic viit tat
DA' MVC THUAT Nay VA cAc Te VIET TAT
AAS
Advanced Antenna Systems - Cac he then anten thich nghi
AES
Advanced Encryption Standard - Chitin ma hem nang cao
AK
Authentication Key - Khoa chimg thgc
ARQ
Automatic Repeat reQuest - Tis dOng lap lai yeu au
ATM
Asynchronous Transfer Mode
AWGN
Additive White Gaussian Noise - Nhieu Gaussian trang cong
BE
Best Effort
BER
Bit Error Rate - Ti le lei bit
BPSK
Binary Phase Shift Keying - dilu the pha nhj phan
BS
Base Station - Tram gee
CDMA
Code Division Multiple Access - Da truy cap phan chia theo ma
CID
Connection Identifier - Dinh danh ket not
CP
Cyclic Prefix - Tien
CPE
Customer Premise Equipment
CRC
Cyclic Redundancy Check - Kiem tra 18i du yang
DFS
Dynamic Frequency Selection — bra chgn tin se dOng
FDD
Frequency Division Duplex - Ghtp kenh phan chia theo tan se
FFT
Fast Fourier Transform - Chuyen dei Fourier nhanh
GSM
ICI
to Wong
Global System for Mobile communications - He thong thong tin
di dOng town cau
InterChannel Interference - Nhieu xuyen kenh
IDFT
Inverse Discrete Fourier Transform - Bien dei Fourirer tin rac
ngtrgc
IEEE
Institute of Electrical and Electronics Engineers cac Ky Su Dien va Dien Tar
HQC
Vien ciia
IFFT
Inverse Fast Fourier Transform - Bien del Fourier ngugc nhanh
ISI
Inter-Symbol Interference - Nhieu xuyen ky tir
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Danh myc thueit ngt7
KEK
LOS
MSHOREG
va cdc tit vdt tin
Key Encryption
Key
Line Of Sight - Tim nhin thing
Mobile Station Handover Request — yeu ciu chuyen giao tram
di dOng
MAC
Media Access Control - Dieu khien truy nhop m8i twang
MAN
Metropolitan Area Network — Mang do thj
MIMO
Multiple Input Multiple Output - Nhieu dau vao, nhieu dau ra
MISO
Multiple Input Single Output - Nhieu dau vio, mOt dau ra
MS
Mobile Station.
NLOS
Non—Line-Of-Sight - IChong tam nhin thing
nrtPS
non—real-time Polling Service
OFDM
Orthogonal Frequency Division Multiplexing - Ghop kenh phan
chia theo tan so trirc giao
OFDMA
Orthogonal Frequency Division Multiple Access - Da truy cip
ghep kenh chia tin se tray giao
PDU
Packet Data Unit - Don vj gOi der lieu
PKM
Privacy and Key Management - Quin ber sv rieng to va kh6a
QAM
Quadrature Amplitude Modulation - Dieu the bien dO true giao
QoS
Quality of Service - Chit Itrong djch vv
QPSK
Quadature Phase Shift Keying - dieu the pha trvc giao
RSSI
Receive Signal Strength Indicator — Cuong dO tin hieu nhin
duqc
so v8 tuyen
RF
Radio Frequency - Tin
rtPS
real-time Polling Service
SDU
Service Data Unit - Dun vj dtk lieu djch vtr
SLA
Service-Level Agreement - Theta thu$n mirc (Bch vv
SNR
Signal-to-Noise Ratio — Ti le tin hieu ten nhien
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Danh myc thuat ngu va ccic tit vilt tat
SS
Subscriber Station - Tram thue bao
TDM
Time Division Multiplexing — Ghep With phan chia theo thin
gian
TDMA
Time Division Multiplexing Access — Da truy cap phan chia
theo thin gian
TEK
Traffic Encryption Key - Khda ma h6a luu lucrng
UDP
User Datagram Protocol
UGS
Unsolicited Grant Services
UMTS
Universal Mobile Telephone System
WiFi
Wireless Fidelity
WiMAX
Worldwide interoperability for Microwave Access
WLAN
Wireless Local Area Network — Mang cuc khong day
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Mix dins
M O DA U
De dap ang nhu cau thuc to hien nay ve toe deo truyen da lieu cao, bang th8ng
Ong han, h6 trq nhieu mire djch vu (QoS), tinh di dOng nOi mang hay gifta cac
mang sir dung cong nghe khac nhau vit gifts cac nha cung cap djch v6i nhau. VI
vay xu huong phat trien mang the he sau di sau vio tinh chart h6a, cho phop xity
dtmg kieu mang kh8ng phi; dmijc vao cac duet bi sir dung no vi tuang tac giOra cac
kieu mpg khac nhau b mat dO cao. MOt cling ngh'e da vi dang duqc phat trien
nham dap (mg cac nhu au ke tren, duqc chuan hem beri t6 chic IEEE (Institute of
Electrical and Electronics Engineers) - cling nghe IEEE 802.16 hay con duqc gqi la
cong nghe WiMAX dinh cho ket not bang thong Ong khong day 6 khan cach
16n.
Cac cong nghe truy cap kh8ng day hien tai con han the ve tee dO truyen du
lieu, h6 trq mac dich vu chua linh hog, pham vi phi song hp. Do do cong nghe
WiMAX duqc phat trien luting t6i nave dich khAc phuc, hob thin vi fling cao cac
dac tinh manh me cita cong nghe mang khong day.
Luan van nay se tap thing vao viec nghien cfru cac 16p Dieu khien truy nhop
mei truang MAC trong cong nghe 802.16, qua do trinh bay nhOng van de co ban ve
cong nghe WiMAX ding nhu cac chart WiMAX, cac Id thug img dung trong
WiMAX, mo hinh phan 16p tong cong nghe WiMAX
Tiep theo, de lain re quy trinh lam viec cita he thong mang WiMAX, luan
van se gieri thieu mo phong hog dOng dui he thong WiMAX cling nhu phan m'em
ho trq m8 phong cac hog dOng nay.
Ulan van bao gem 4 clurcmg:
Chuang 1: Gi6i thieu chung ve WiMAX.
Chuang 2: Cac kg dwelt duqc sir dung trong WiMAX.
Chuang 3: Kien true mang truy cop WiMAX.
Chuang 4: Chuang trinh m8 phi:mg WiMAX.
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Chuang I: Gied thigu chung ve WiMAX
CHUCING 1. GI61 THItU CHUNG VE WiMAX
1.1. GIOI THItU CHIANG
WiMAX la mOt cong nghe cho phdp truy c#p bang Ong vo tuyen den du Si
nhu mOt phuong thirc thay the cho cap va dyeing day thue bao so DSL. WiMAX
cho phep ket n6i bang Ong vo tuyen c6 djnh, nomadic (nguOi sir dung co the di
dOng nhung c6 djnh trong 18c kat rthi), portable (ngutri sir dung co the di chuyen vOi
the do cham) vi cuOi ding la di dOng ma khong can a trong tam nhin thing LOS
(Line-Of-Sight) tri,rc trap vii tram g6c BS (Base Station). WiMAX khac phuc duce
cac nhuqc diem cita cac phuong phap truy nhip hien tai, cung cap mOt phuong tien
truy nhip Internet khong day ding hqp co the thay the cho ADSL vi WiFi. He thtong
WiMAX c6 kha nang cung cap duemg truyen co the dO len den 70Mbit/s vi yid ban
kinh phit song cita mOt tram anten phat len den 50Km. MO hinh phu song dm mang
WiMAX tuong tu nhu mang dien thoai to bao. Ben canh d6, WiMAX cling host
dOng mem deo nhu WiFi khi truy cip mang. m6i khi may tinh mu& truy nhip
mang no 0 ur Ong ket n6i den tram anten WiMAX gin nhat.
Trong chuong nay, chitng to se tim hien khai niem co ban ve WiMAX, cac chuan
WiMAX hien nay, cac bang tartco the sir dung cho WiMAX, cac uu diem va lqi ich
cua WiMAX mang lai, &mg thtd la tinh hinh trien khai WiMAX tren the gieri vi tai
Viet Nam
1.2. ICHAI NEN
WiMAX (Worldwide Interoperability of Microwave Access) la he thOng truy
nhip vi ba co tinh tuong thich toin cAu dua ten co so tieu chuan IEEE 802.16
WirelessMAN (Wireless Metropolitan Area Network). Hq 802.16 nay dua ra nhUng
lieu chuin, chi tieu ky thujt nhim tip trung giai quyet the van de trong mang vo
tuyAn bang Ong diem — da diem ve giao dien vo tuyen bao Lip dieu khien
truy cop mill trutmg (MAC) vi 16p v#t 1St (PHY).
WiMAX la mOt chuan khong day dang phat trien rat nhanh, hira hgn tao ra khi
nang ket not bang thong rung the dO cao cho ca mang c6 djnh Ian mang khong day
di dOng. Hai phien ban cua WiMAX duqc dua ra:
Fixed WiMAX (WiMAX co d(nh): Dva tren tieu chain IEEE 802.16-2004, duce
thiet ke cho loai truy nh#p c6 djnh va luu dOng. Trong phien ban nay sir dung ky
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Chuang 1: Gioi thieu chung v'J WiMAX
thuat ghep kenh phan chia theo tan s6 trvc giao OFDM (Orthogonnal Frequency
Division Multiple) host dOng trong ca m8i trutrng nhin thing — LOS (line-of-sight)
va kh8ng shin thing — NLOS (Non-line-of-sight). San pham dva tren tieu churn
nay hien tai da dopy cap chung chi va thuong mai hem.
Mobile WiMAX (WiMAX di dOng):
dva tren tieu chuan IEEE 802.16e, duqc thiet
ke cho loai truy cap xach tay vi di dOng. ve co bin, tieu chuan 802.16e duqc pith
trien tren co so seta doe tieu chuan IEEE 802.16-2004 de tOi uu cho cac kenh vo
tuy6n di dOng, cung cap kha nang chuyin yang — handoff vi chuyen mang —
roaming. Tieu chuan nay sir dung phucmg thirc da truy cap ghep kenh chia tan s6
tri,rc giao OFDMA (Orthogonnal Frequency Division Multiple Access) — 11 skr ph6i
hqp dm k9 thuat ghep kenh vi ky that phan chia tan s6 co tinh chit tri,rc giao, rat
phu hqp v6i moi toting truyen dan da &Ong nhim tang thong loqng cling nhu
dung loqng mang, tang dO linh host trong viec quin 19 tai nguyen, tan dung toi da
ph6 tan, cai thin kha nang phi song von ac loai dja hinh da
WiMAX da duqc phit trien va khic phuc duqc nh&ng nhirqc diem et' cac ding
nghe truy cap bang rung truck day, cu the:
Cau Vac mem deo: WiMAX h6 trq cac cau true he thOng bao gem diem — da
diem, cling nghe lutri (mesh) vi pha song khap nu:A nod. Dieu khien truy nhap mai
toting — MAC, phuong tien truyen din 1145 trq diem — da diem va djch vu rung khip
bed lap ljch mot khe thtri gian cho mOi tram di dOng (MS). Neu co duy nhat WA MS
trong mang, tram gOc (BS) se lien lac vori MS tren co sty diem — diem. Mot BS trong
mot eau hinh diem — diem co the sir dung anten chum hyp ham de bao phu cac
khoirtg cach xa han.
Chat hung djch vu QoS: WiMAX co the duqc t6i uu dOng d6i yea Mn hqp lou
lucmg se duqc mang. Co 4 loai djch vu doge h6 trq: djch vv cap phat to nguyen
(UGS), djch vu h6i wing thin gian thvc (rtPS), djch vo h6i Wong khong theri gian
thvc (nrtPS), no lye t6t 'that (BE).
Trien khai nhanh, chi phi thap: So sinh yeti trien khai cac giai phip co day,
WiMAX you cau it hoac kh8ng co bat cir sv xay dung thiet lop ben ngoii. Vi du,
dao he) de tao ranh cac dutmg cap thi khong you au. Ngoii ra, dva ten cac chuin
ma cua WiMAX, se khOng co sv dOc guy& v'e tieu chuan nay, dan den viec earth
tranh cua nhieu nha sin xuat, lam cho chi phi du to mot he thot ng giim ding ke.
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Chuang 1: Geri thieu chung ve WiMAX
Dich da mac: Cach thirc nai ma QoS duce phan phat not chung dva vao sv
them thuan mire dich vti (SLA - Service-Level Agreement) giui nha cung cap dich
vu va ngu&i sir dung cu6i cling. Chi tie[ hun, mOt nha cung cap djch vp c6 the cung
cap the SLA khic nhau tai cac thud bao !chic nhau, then chi tad nhang ngtrai dung
khac nhau sir dung cling MS. Cung cap troy nhap bang rang co djnh trong nheng
khu vrc do thi va ngoai o, nth chat Itrqng cap diing thi kern hoac dua vao kh6 khan,
khac phtic thiet bj s6 trong nheng viing mat do thap nai ma cac nhan M ding nghe
vi kinh to thvc hien phat trien bang rung rat thach that.
Tinh ttrcmg thich: WiMAX duqc xay dung de tra thanh mOt char' quok tot, tao ra
str de ding d6i vii nguai dimg cu6i cling de truyen tai vi sir dung MS cia hp o cac
vi tri khac nhau, hoac vii cac nha cung clip djch v4 khac nhau. Tinh ttrcmg thich bao
ve str dau to ctia mOt nha van hanh ban dau vi no c6 the chpn Iva thiet bj to cac nhi
dai ly thiet bj.
Di dOng: IEEE 802.16e ba sung them cac dac diem chinh h8 trq khi flan di
dOng. Nhftng cai tien lap vat ly OFDM (ghdp kenh phan chia tan sit') there giao) va
OFDMA (da truy nhap phan chia tan s6 Dix giao) de ha trq cac thiet bi vi cac djch
vu trong mOt moi truing di dOng. NhOng cai tien nay, bao g6m OFDMA ma ring
dtrqc, MIMO (Multi In Multi Out - nhieu dau vao nhieu dim ra), vi h8 trq d6i vii
che dO idle/sleep vi handoff, se cho phop khi thing di dOng day di 6 tic do ten 160
km/h. Mang WiMAX di dOng cho phdp ngtrai sir dung do the troy cap Internet
khong day bang thong rung tai bat ca tau co phi sang WiMAX.
Hoat dOng NLOS: Kha nang hpat dOng cia mang WiMAX ma khong del hei tam
nhin thing giaa BS va MS. Kha thing nay cia no &dip cac sin pham WiMAX phan
phat dai thong Ong trong mOt mei truemg NLOS.
Phi song rung han: WiMAX ho trq dung nhieu mire dieu che, bao gom BPSK,
QPSK, 16QAM, 64QAM. Khi yeu cau yeti bO khuech dai cling suit cao vi hoot
dOng vii dieu che mire thap (vi du BPSK hoac QPSK). Cac he th6'ng WiMAX co
the phi sang mOt yang dia ly Ong khi &rang truyen gigra BS va MS khong bi can
tra. Ma Ong pham vi bj giai han hien tai cia WLAN cling cling (hotspot) den pham
vi rung (hotzone). nhang dieu kien Mt nhat co the dat duqc pham vi phi song 50
km vii tic do da lieu bi ha thap (melt vii Mbit/s), pham vi phi song dien hinh la
gan 5 km veri CPE (NLOS) trong nha va gin 15km vii mOt CPE duqc n6i vii mOt
anten ben ngoai (LOS).
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Chuang 1:
Gieri thieu chung ve WiMAX
Dung liking cao: Co the dot dirge dung lugng 75 Mbit/s cho cac tram g6c vgi
met kenh 20 MHz trong cac dieu kiln truyen song tot nhit.
Tinh ma rOng: Chitin 802.16 -2004 h6 try cac dai thong kenh tin s6 ve tuyen
(RF) mem deo va sir dung 1a1 cac kenh tart .' so nay nhtr la mot cach de tang dung
lugng ming. Chuan ding dinh re h6 try &Si yeti TPC (dieu khien cong suit phat) vi
cac phop do chat lugng kenh nhu cac cong cu them vao de hO try sir dung ph6 hieu
qua. Chuan da dugc thiet ke de dat tS le len ten hang tram tham chi hang nghin
ngtkri sir dung trong mOt kenh RF. HO try nhieu kenh cho phdp cac nha the tao thiet
bi cung cap met phuong tin de chit trcing vao pham vi sir dung ph6 vi nhUng quy
dinh cap phat duck not re beri cac nha van hank trong cac thi twang quiic to thay
dei khac nhau.
1.3. CAC CHUAN CIA WiMAX
13.1. Chitin IEEE 802.16 - 2001
Chuin IEEE 802.16-2001 duck hoar .' thanh vao thing 10/2001 va dugc cong b6
vao 4/2002, dinh nghia dac to Icy thuot giao dien kh8ng gian WirelessMANTm cho
cac mang yang do thi. Dk diem chinh dm IEEE 802.16 — 2001:
Giao din khong gian cho hg thong truy Whip kung day bang rOng co dinh hgat
dOng o dai tin 10 — 66 GHz, can thoa man tint nhin thing.
Lop vat IS, PHY: WirelessMAN-SC.
T6c dO bit: 32 —134 Mbps vol kenh 28 MHz.
Dieu the QPSK, 16 QAM va 64 QAM.
Cac dai thong kenh 20 MHz, 25 MHz, 28 MHz.
Ban !anti cell: 2 — 5 km.
Ket n6i co dinh huOng, MAC TDM/TDMA, QoS, bao mat.
13.2. ChuAn IEEE 802.16a
Vi nhang kh6 khan trong then khai chart IEEE 802.16, Inking vao viec sir dtmg
tin so tir 10 — 66 GHz, mOt dy an sira &Si co ten IEEE 802.16a da dugc hoin thanh
vao thing 11/2002 va dugc cong b6 vao tang 4/2003. Chuan nay dugc ma king h6 .
s6 trong bang tan 2-11 GHz, bao g6m ca trygiaodnkh ctagn
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Chuang 1: Gioi thieu chung ve WiMAX
nhang ph6 cAp phep va khong cap phdp vi khong can thoa man dieu kien tam nhin
thing. Dac diem chinh ctia IEEE 802.16a:
B6 sung 802.16, cac hieu chinh MAC vi cac dac diem PHY them vao cho dal 2 —
11 GHz (NLOS).
T6c de bit: UM 75Mbps yeti kenh 20 MHz.
Dieu the OFDMA vai 2048 song mang, OFDM 256 song mang, QPSK, 16
QAM, 64 QAM.
Dai thong kenh co the thay deoi Ora 1,25MHz vi 20MHz.
Bin kinh cell: 6 — 9 km.
Lop It 13% PHY: WirelessMAN-OFDM, OFDMA, SCa.
Cac chirc nang MAC them vao: 116 trq PHY OFDM vi OFDMA, h6 trq ding
nghe Mesh, ARQ.
1.3.3. Chan IEEE 802.16 2004
-
Thing 7/2004, chitin IEEE 802.16 — 2004 hay IEEE 802.16d duqc chap thong
qua, kat hqp cua cic chitin IEEE 802.16 — 2001, IEEE 802.16a, img citing LOS 6
dai tan s6 10 - 66 GHz vit NLOS o dal 2 - 11 GHz. Kha Tian vo tuyen b6 sung nhir
la "beam forming" vi kenh con OFDM.
1.3.4. Chuin IEEE 802.16e
DAu nam 2005, chuan khong day bang thong rung 802.16e van ten gni Mobile
WiMAX da duqc phe chuan, cho phep tram gtic kAt n6i toi nhOng thiet bi dang di
chuyen. Chuan nay giup cho cac thitt bi tir cac nha sin xuat nay co the lam viec,
ttrong thich tot veci cic thiet bi tir cic nhil sin xuat khac. 802.16e hnat dOng 0 cac
bang tan nho ham 6 GHz, t6c dO len tai 15 Mbps veri kenh 5 MHz, ban kinh cell tir 2
— 5 km.
WiMAX 802.16e co hit trq handoff vi roaming. sa dung SOFDMA, mOt cling
nghe dieu the da sang mang. Cic nhl cung cap dich vu ma then khai 802.16e cling
co the sir dung mang del cung cAp dich vu c6 dinh. 802.16e h6 trq cho SOFDMA
cho phep s8 song mang thay d6i, ngoli cic m8 hinh OFDM vi OFDMA. Sr phan
chia song mang trong mo hinh OFDMA (kw thiet ke de tai thieu anh hueng cua
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Chuang 1: Giol thieu chung ve WiMAX
nhiOu phia thiet bj nguen clUng veri anten da huerng. Cu the ham, 802.16e dua ra hO
trq cai ties ho trq MIMO va AAS, cling nhtr cac handoff cling vi mem. NO cling cai
lien cac kha nang tiet kiem cling suet cho cac thiet bi di dOng va cac die diem bao
mat linh host hon.
802.16
Tinh
trang
Dii tin
(J'ng
dyng
802.16-2004
802.16-2005
Hoin thie'n vao
Holm thie'n vao thang
Hoan thin vao thing 12thing 12-2001
6-2004
2005
10-66 GHz
Co dinh, tam
nhin thing (LOS)
2-11 GHz
Co djnh, lchting nhin
thing (NLOS)
2-11 GHz cho c6 djnh;
2-6 GHz cho di dOng
C6 dinh vi di dOng,
khong nhin thing (NLOS)
Citu
Diem — da diem,
Diem — da diem, mang Diem — da diem, mang
true lop
mang luai
lueri
lucid
MAC
Mo hinh
A
truyen
song
Dieu chi
Ting
tin so
de lieu
Ghip
Werth
Don sang mang, 256
Don song mang, 256 OFDM hoac S-OFDM veri
Don song mang
OFDM, 2048 OFDM
128, 512, 1024, 2048 song
mang con.
QPSK, 16QAM,
QPSK, 16QAM,
64QAM
64QAM
32-134 Mbps
Khii
TDM/TDMA
QPSK, 16QAM, 64QAM
1-75 Mbps
1-75 Mbps
Kh6i
Kh6i
TDM/TDMA/OFDMA
TDM/TDMA/OFDMA
Song
cengs
TDD va FDD
TDD va FDD
TDD va FDD
DO rOn g
20, 25, 28
1.75, 3.5, 7, 14, 1.25,
1.75, 3.5, 7, 14, 1.25, 5,
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Chuang 1:
Glen thiOu chung 14. WiMAX
5, 10, 15, 8.75
kenh
truyan
(MHz)
Giao
then
kheng
gian
Xir 1f
WiMAX
10, 15, 8.75
WirelessMAN-SCa,
WirelessMAN-SCa,
WirelessMANWirelessMAN-OFDM, WirelessMAN-OFDM,
SC
WirelessMAN-OFDMA WirelessMAN-OFDMA
256-OFDM nhu 11
WiMAX co dish
Khong
Bang 1.1.
Tom
S-OFDMA nhu la
WiMAX di dOng
kit cac clOc trung ca ban czia churn WiMAX[6]
1.4. PH6 WiMAX
1.4.1. Bang tan ding ky
Cac giii phap dang ky cung cap cac uu diem chit ltrqng dich vu duqc cai thien
cao ham cac giii phap kh6ng dang ky, chap &tan NLOS Mt han a cac tan M thip,
no co mot ngan qiiy cong sulk clueing xu6ng rang han va co the ho trq cac anten
trong nhit tot han. Giai phap dang ky cho phep kient soit qua cach sir dung ph6 va
nhieu.
Bang tin Mug ky 2,5 GHz
DA duqc cAp phat trong phan lan cac ntrac tren the giai, bao g6m bitc My, My
Latin, (long va tay Au va nhiau vimg cila chin A - thai birth &rang. M6i quitoc gia
throng cap phat dai khac nhau, vi vay ph6 duqc cAp phitt qua cac vimg co the tir
2,495 GHz din 2,690 GHz. Tong ph6 kha dung la 195 MHz, bao g6m cac dai
ph6ng ve va cac kenh MDS, gtla 2.495 GHz va 2.690 GHz. H6 trq FDD, TDD. Phi;
tren moi dang ky la 22.5 MHz, met block 16.5 MHz va met block 6 MHz, tong s6 8
dang ky.
Bang tin dang ky 3,5 GHz.
chau Au, vien chitin vien thong chau au da phan ph6i dai 3,5 GHz, bit dau
duac sir dung cho WPLL, cho cac giii phip WiMAX dang ky. Ring ph6 kha dung,
thay del theo qu6c gia nhung nal chung khoang 200MHz giaa 3,4 GHz va 3,8 GHz.
HO trq ca FDD va TDD, met vai quac gia chi sir dung FDD trong khi cac quo tc gia
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Chuang 1: GUN thieu chung ve WiMAX
khac cho phdp sir dung FDD hoac TDD. Pho tren moi clang ky thay dei tir 2x5MHz
dEn 2x56 MHz.
1.4.2. BAng tan khOng clang k5T 5GHz
Phan 16n the quoc gia town the gieri da six dung phi). 5 GHz cho cac phircmg tin
lien lac kh8ng dang ky. Cac bang 5,15 GHz vi 5,85 GHz CIA duqc chi dinh nhu
khong dang Icy trong phap lent the gieri.
Cac gill phap kh8ng ding Icy cung cap melt vii thuitn lqi chinh ham cac giii phap
Bang ky, bao gem chi phi ban dAu thAp ham, rut ra nhanh han, vi mOt bang chung co
the duqc sir dung 6 phan torn the gi6i. Cac lqi ich nay dang thu hat sq quan tam vi
co khA nang cho su chap nhan bang rOng nhanh chung.
Tuy nhien met giai phip khong Clang ky thi khA nang nhieu cao han, vi nhiEu su
canh tranh dal v6i cac nha kink doanh bat dOng sin cho viec trien khai. Mot giii
phap khong clang Icy se khong duqc xem nhu mot su thay the cho giii phap clang Icy.
Moi giii phap cung cap mOt thi twang khac nhau dua vao su them hie]) gifra chi phi
va QoS.
1.5. TRUYEN SoNG
Hien tai nhieu cong nghe !thong day bang th8ng rong chi co the cung cAp phu
song clang LOS, cong nghe WiMAX duqc thi uu cung cAp ca Icha nang phi' song
LOS va NLOS. Mac dit vay, ca 2 clang phii song deu bi anh htrerng it nhieu bed cac
dac tinh cda moi trutmg truyen, cac Mn that Iron throng din vi tai nguyen het n6i v8
tuyen.
MOt tin hieu trong lien lac LOS la mOt tin hieu ma duqc phat ten 1 duting truyEn
true tiep, khong co vat can tir may phat den mot may thu hay tir may pith den may
thu IA thin shin thing. lien lac LOS you au phi') 16n mien Fresnel khong bi ngan
can bai SS vat nao, neu you cau nay khong duce th6a man thi co su giam thieu
Bang ke cueing dO tin hieu gift tram thu vi tram phat. DO her Fresnel dtrqc yeu eau
bed tin s6 hog dOng cila lien lac vi kiting each gifra may phat vi may thu.
Trong lien lac NLOS, tin hieu den may thu bi phin xa, tin xa vi nhieu xa do
dtrtmg truyen bi cac vat can gay ra. Cac tin hiEu den may thu bao gem cac tin hiEu
tir dyeing true tiep (tin bleu chink), cac tin hiEu bi phin xa nhiEu Ian, nang 1uqng bi
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Chuang 1: Glut thieu chung ve WiMAX
tan xa va cac duemg truyen bi nhieu xa. Cac tin hieu nay co khoang tre khac nhau,
suy hao, phan cuc,... DO chinh la nguyen lain gay ra nhieu ISI va meo tin hieu,
day kheing phai la yin de Ion del vol lien lac LOS, nhung veri LOS lai la van de
chinh.
Ngoai ra, hien tugng da duOng co the gay ra hieu tugng phan cuc. Khic phoc
tinh trang nay, viec sir dung lai tin s6 nhu la mot Bien phap manh me cilia LOS
nhung lai kho giii guy& trong ang clang NLOS.
MOt hg thing vo tuyen sir dung cac tin hieu da duemg hieu qua tao thuan Igi de
cung cap dich vu trong dieu kiln NLOS. MOt san phin chi don thuin tang cong suit
de xuyen qua cac vat can (doi khi ggi la "can tam nhin thing") thi kh8ng dugc coi la
cong nghe NLOS bed vi phucmg phap nay can dui vao duong truyEn true ti'ep du
manh chic khong sir dung cac !tang lugng sinh ra trong cac tin hieu gian dep.
NLOS tao ra cac uu diem Clang ke, vi du nhu cac yeu au lap lich ke hoach chat
the va gieri han chieu cao anten ma thutmg thi quy Binh chieu cao anten ciia LOS
kh6ng cho phep. Vic ha thap chiEu cao ciia anten la met thuan Igi dE giam nhieu
kenn chung gifra cac vi tri cell lien ke nai ma cac to bio tram g6c dugc then khai ke
nhau tren pham vi Ong kitten tar' s6 dugc sir dung co gieri hen.
INTERIMT
BACKBONE
MINAS 802.24
TRANSMITTER
LIRE OF SIGWI
WICKHAM
SIMM
T=ESTA
V trOMI
LIMAS YEA
RSTWOINI
Hinh 1.1. Minh hpa hpat 445ng WiMAX [1O]
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Chuang 1: Giai thieu chung ve WiMAX
Cong nghe NLOS cling giam phi ten cai dot bang each dat clued cac mai the thiet
bi CPE dung nhu nguyen ban va giam bat kh6 khan dinh vi tri cac dia diem dot CPE
thich hqp. C6ng nghe cling giam bat nhu eau quan sat vi tri thiet bi phia throe va cal
thien dO chinh xac cua cac cong cv lap ke hooch NLOS.
C6ng nghe NLOS va Meng tinh nang duce fling cao trong WiMAX too !chit
nang sir dung thiet bi phia dAu Ichach hang (CPE) trong nha. Dieu nay co hai kh6
khan chinh; dau tien la khic phvc nhOng ten hao xuyen qua tea nhA va thir hai, phi)
song cac khoang each hqp IST vii cong suit truyen va cac anten th'Ap hen ma &rang
duqc ket hap vii the CPE trong nha.
Trartattry Antense
Hinh 1.2. Truyin song trong Thremg hqp NLOS 1101
1.6. UV DIEM VA NHUQC DIEM CUA CONG NGHE WiMAX
Mvc tieu cua t6 chirc IEEE khi phat trien tieu chuAn 802.16:
a
Xay clung mot pham vi chuAn di
clang cho sv phat trien va phei hap gift cac
nha san xuAt, nha cung cap va ca ngtrai sir dung.
Thilc dAy qua Wirth chimg nhan ph6i hap hoot dOng va tuan chit cho cac he thring
truy nhap vo tuyen bang rOng tren toan cAu.
Nhu vay, voi mvc tieu de ra, cac tieu chuAn cho WiMAX co Iqi ich het sue to lan
doi voi cae nhA san xuat, cac nhi cung cap dich vv va ca ngtrai sir dung dich vv.
fled voi nhi sin ausit:
Tren ca s6 tieu chuAn chung, nhi sin xuAt co the nhanh cheng phat trien cac san
phini ma it phai chi phi cho viec nghien ciru, too thanh phAn va (Lich 91 mai.
MOt nha sin xuAt co the top trung vao mot linh we (ching han tram g6c hay
CPE) ma kh6ng can thvc hien day du giii phip tir du cued den dAu
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