de tai tim hieu cong nghe mang khong day va mobile wimax

7/31/2019 De Tai Tim Hieu Cong Nghe Mang Khong Day Va Mobile Wimax

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HC VIN CNG NGH BU CHNH VIN THNG--- oOo ---

TIU LUN

TI:TM HIU CNG NGH

MNG KHNG DY V MOBILE WiMAX

Ngi hng dn : TS.

Hc vin thc hin : HUNH TH HNG ANHLp :Nin kho :

H Ni, thng 09/2006


2/22

LI M UMng khng dy l mt trong nhng bc tin ln nht ca ngnh my tnh. Nm ngoi, hng

chc triu thit b Wi-Fi c tiu th v d bo nm nay s c khong 100 triu ngi s dng.Nhng ngi a thch Wi-Fi tin rng cng ngh ny s gt ra l ht nhng k thut kt ni khng

dy khc. V d, h cho rng cc im truy cp hotspot s cnh tranh vi cc mng in thoi di ng3G vn ha hn kh nng truyn pht d liu tc cao. Tuy nhin nhng suy lun nh trn bthi phng. Wi-Fi ch l mt cng ngh sng ngn v s khng bao gi c th cung cp c khnng bao trm rng nh mng di ng, nht l khi cc mng ny ang ngy mt pht trin mnh hn

v quy m nh nhng dch v chuyn vng (roaming) v cc tha thun tnh cc lin quc gia.Tuy nhin, ch trong mt vi nm na, th h mng u tin da trn cng ngh mi WiMAX, hay

gi theo tn k thut l 802.16, s ra i v tr nn ph dng. Nh chnh ci tn ca mng ny chothy, WiMAX chnh l phin bn ph sng din rng ca Wi-Fi vi thng lng ti a c th ln n70 Mb/giy v tm xa ln ti 50 km, so vi 50 m ca Wi-Fi hin nay. Ngoi ra, trong khi Wi-Fi chcho php truy cp nhng ni c nh c thit b hotspot (ging nh cc hp in thoi cng cng)th WiMAX c th bao trm c mt thnh ph hoc nhiu tnh thnh ging nh mng in thoi ding.

Tp tiu lun ny trnh by nhng nt tng quan nht cng ngh mng khng dy v gii thiu

tng quan v cng ngh WiMAX.Ti xin trn trng cm n Thy gio TS. tn tnh hng dn, truyn t nhng

kin thc qu gi, cung cp ti liu tham kho v ch bo cho ti phng php lm vic khoa hc.Xin chn thnh cm n cc anh ch v cc bn hc vin trong lp nhit tnh gip ti trong

vic tm kim ti liu thc hin tiu lun ny.Trong qu trnh lm tiu lun, tuy ht sc c gng song chc chn khng trnh khi nhng sai

st. Rt mong nhn c s gp ca Thy, cc anh ch v cc bn hc vin trong lp ni dungca tiu lun c hon chnh hn.

H Ni, ngy 30 thng 09 nm 2006

Ngi thc hin

Hunh Th Hng Anh

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1. Th no l khng dy?

Mng khng dy (Wireless Network) l mt h thng cc thit b c nhm li vinhau, c kh nng giao tip thng qua sng radio thay v cc ng truyn dn bng dy. Mngkhng dy thc s ang thay th cho mng my tnh c dy, cung cp kh nng x l linh ng hn

v t do hn cho cc hot ng kinh doanh. Ngi dng c th truy nhp vo mng Intranet ca nib cng ty, hoc mng Internet (WWW) t bt c a im no trong khun vin ca cng ty mkhng b rng buc bi cc kt ni vt l.

2. Khi nim Wi-Fi v WiMax ?

a. Wi-Fi:

Wi-Fi l tn vit tt ca cm t Wireless Fidelity - mt tp hp cc chun tng thch vi mngkhng dy ni b da trn c t IEEE 802.11 (802.11a, 802.11b, 802.11g). Wi-Fi cho php ccmy tnh hoc PDA (thit b c nhn k thut s) h tr kt ni khng dy c th truy cp vomng Interner trong phm vi ph sng ca im truy cp khng dy (hay cn gi l hotspot). Tc kt ni ca cc chun thuc Wi-Fi rt khc nhau, c th:

802.11: Dng cho mng khng dy, c tc truyn ti d liu t 1- 2Mbps.

802.11a: L phn m rng ca 802.11, p dng cho mng khng dy, c tc kt ni lnti 54 Mbps.

802.11b (cn gi l 802.11 High Rate hoc Wi-Fi): Cng l phn m rng ca 802.11dnh cho mng khng dy, c tc truyn d liu ti a mc 11 Mbps.

802.11g: S dng cho mng khng dy vi tc kt ni ti a trn 54 Mbps.

b. WiMax:

WiMAX l cng ngh kt ni khng dy bng rng (c t IEEE 802.16) vi phm vi phsng rng hn (ti 50km) so vi cng ngh Wi-Fi. WiMax kt ni cc im hotspot ca IEEE802.11(Wi-Fi) ti mng Internet, v cung cp kh nng truy cp bng rng cho ng cp vng DSL ti tn v tr cui cng (nhng vn nm trong phm vi 50km). WiMax cung cp khnng chia s d liu ln ti 70 Mbps, cho 60 doanh nghip s dng cng lc, v hn 1000 ngis dng kt ni DSL 1Mbps.

3. Ti sao li s dng mng khng dy?Nu thng tin c v nh l mch mu ca mi trng kinh doanh ngy nay th mng khngdy s l tri tim iu khin hot ng kinh doanh . Mng khng dy c th truyn thng tinv d liu ti cp lnh o v nhn vin trong mt cng ty m khng quan tm ti v tr ngi lmvic. C rt nhiu ngnh cng nghip pht hin ra li th ca mng khng dy, khng chtrong cng vic hng ngy m cn tc ng ti c cn cn doanh thu.

Kh nng ng dng rng ri trn phm vi rng, s pht trin nhanh chng ca Internet v dchv trc tuyn l li ch ca vic chia s d liu v ti nguyn. Vi mng khng dy, ngidng truy nhp vo thng tin chia s khng cn h thng dy kt ni, khng cn lp t hoc

di chuyn dy khi ngi qun tr mng thit lp m rng mng. So vi mng LAN truyn thng,Mng khng dy c cc u im ni tri v hiu sut, s tin li v chi ph xy dng.

Mng khng dy c th cho php ngi dng truy cp thng tin theo thi gian thc t bt

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c v tr no trong khun vin v phm vi cng ty m khng phi tm kim cc v tr c ktni mng qua Ethernet, do vy s tng c nng sut lao ng. Nh m t trong hnhdi y: mi vng trn tng trng cho mt vng bao ph ca mt AP (cho php ccmy tnh trong vng lin lc vi AP bt k v tr no). Khi mt my tnh di chuyn t bn tri sang bn phi th cc thit b mng khng dy AP s t ng chuyn vngqun l m bo cho kt ni vi mng.

Hnh 1: Cu hnh multicell in hnh s dng backbone LAN hu tuyn

S d dng v tc trin khai: mng khng dy khng yu cu qu trnh lp t cp tn kmv mt nhiu thi gian.

Ci t, cu hnh linh hot: cng ngh khng dy cho php mng kt ni n mi ni i vimng c dy l khng th. Vic ci t cu hnh thit b Aironet Accesspoint ca cc cng

hng sn xut hin nay u c th thc hin thng qua SNMP Manager, Telnet, FTP v WebBrowser, trong s dng WEB Browser c a thch hn v kh nng thun tin v ngin.

Hnh 2: Cc phng thc cu hnh Aironet Accesspoint

H thp chi ph trin khai: mc d u t ban u v phn cng c th cao hn mng c dy,tuy nhin xt chi ph tng th v chi ph theo tui th c th thp hn ng k. V lu di,Mng khng dy s em li li ch rt ln trong cc mi trng ng yu cu s di chuyn v

thay i nhiu. Kh nng m rng: h thng Mng khng dy c th cu hnh trong nhiu m hnh p ng

cc ng dng v cu hnh c th d dng thay i v phm vi t mng im - im xy dng

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cho s nh ngi dng n cc mng phi hp vi hng ngn ngi dng cho php chuynvng trn phm vi rng. Hn th na, i vi cc v tr xa, ngoi vng ph sng ca mt thit

b AP, c th s dng thm mt thit b AP, c cu hnh ng vai tr thit b chuyn tip(repeater) m rng vng lin lc ca mng khng dy.

Hnh 3: Cu hnh im AP lm chc nng repeater

Kh nng phn ti v dch chuyn tc truyn dn

Aironet Accesspoint h tr kh nng chia ti nu xy ra nghn mng ti mt thi im nhtnh trong mng

Hnh 4: AP thc hin chia ti (Load Balacing)

Aironet Accesspoint cn cung cp tnh nng t ng iu chnh tc truyn dn m botnh lin tc ca kt ni vi mng:

Hnh 5: Kh nng dch chuyn tc truyn dnm bo duy tr kt ni trong mng khng dy

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Cc tc ny c th thay i gia cc tc 1Mbps, 2Mbps, 5,5Mbps v 11Mbps. Trn cs c th to ra cc vng bao ph ca thit b mng Mng khng dycho cc tc yucu khc nhau, nh trong hnh trn.

Tnh nng lc gi, World Mode, d phng, phn ti v tnh nng qun l tin tin.

Hnh 6: Nhng tnh nng vt tri ca Aironet

4. Mng khng dy hot ng nh th no?

Trong mt m hnh mng khng dy in hnh, b chuyn i (hay cn gi l im truy cp) skt ni ti mng c dy t mt v tr c nh thng qua cp Ethernet chun. im truy cp nhn, lutr tm (buffer) v truyn d liu gia cc thnh phn (i tng) ca mng khng dy (my tnhxch tay, my in, thit b cm tay hoc bt c mt thit b khng dy no) vi kin trc mng cdy. Mt im truy cp n c th h tr mt nhm nh ngi dng, v c vng ph sngtrong khong chu vi t 10m n hn 100m. im truy cp c th c lp t ti bt c v tr

no trong cng ty min l ph sng phi c m bo. Cc thit b Access Point Aironet,ng vai tr mt thit b truy nhp mng LAN s dng v tuyn, cho php cc thit b mngnh PC, Laptop truy nhp vo mng nh mng LAN thng thng. Mi my tnh PC, Laptopc trang b mt Card mng c h tr truy nhp v tuyn s thc hin vic kt ni vi mngthng qua AP.

Hnh 7: Nguyn l hot ng ca Access Point

Ngi dng c trang b thit b cm tay hoc my tnh xch tay c th truyn d liu tiim truy cp khi ang trong vng ph sng ca thit b m khng cn s dng cc dy mng,

iu ny to nn nhng li th nht nh ca mng khng dy cho cc vn phng m c sthay i v tr thng xuyn ca ngi truy nhp, vic lp t h thng mng n gin hn. Ngoi ra,kh nng chy d phng ca cc thit b mng khng dy cho php cc my tnh c th va di

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chuyn va kt ni mng m khng nh hng n cht lng ca kt ni. Thit b khng dyc th giao tip vi h iu hnh mng thng qua cc card iu hp khng dy (thng l cardgiao din mng NIC), cng tng t nh trng hp s dng b iu hp ISA hoc PCI dnhcho my tnh bn.

Hnh 8: Microcell vi Access Point

5. i tng s dng mng khng dy l ai?

Theo cc nh phn tch ca hng In-Stat/MDR, ngnh cng nghip mng khng dy s t doanhthu 5,2 t USD trong nm nay (2005), v d kin s tng nhanh trong cc nm ti. S tng trngny c s ng gp rt ln t nhn thc v li ch ca mng khng dy t pha doanh nghip.Mng khng dy ang tr nn ph bin trong cc mi trng :

H thng thng tin doanh nghip: Cc nh qun l mng c th di chuyn nhn vin,

lp ra cc vn phng tm thi, hoc ci t my in v nhiu thit b khc m khng b nh hng bichi ph v tnh phc tp ca mng c dy. Cp lnh o c th truy cp vo h thng thng tin quantrng ca cng ty t phng hp thng qua cc thit b cm tay c ci t card khng dy .

Du lch: Khch sn v cc im du lch c th x l thng tin t phng, yu cu dch vhoc thng tin v hnh l ca khch hng.

Gio dc: Sinh vin v ging vin c th lin lc vi nhau t bt c v tr no trong khunvin i hc trao i hoc ti v cc bi ging c sn trn mng. Mng khng dy cn gim thiunhu cu s dng phng lab (phng thc hnh) my tnh ca sinh vin.

Thng tin sn phm: Cc nhn vin chu trch nhim v xut kho c th cp nht v trao icc thng tin quan trng ca sn phm.

Y t: Bc s, y t c th trao i cc thng tin v bnh nhn hoc liu php cha trv..v..

6. Chi ph u t cho mng khng dy :

Vic trin khai mng khng dy i hi cc doanh nghip phi u t cho thit b phn cng(im truy cp, b iu hp mng khng dy), phn mm, th tc ci t v mt s lng tngi kin thc v cng ngh thng tin. Qu trnh ci t v sa cha s khng phi tn qu nhiucng sc lao ng v khng dnh dng nhiu ti dy cp truyn d liu. Tng t, qu trnh di

chuyn, b sung v sa i i vi mng khng dy cng n gin hn, v do c th gim cgi thnh lao ng. Do tnh hiu qu lao ng c tnh cho kh nng linh ng ca nhn vin nncc doanh nghip u t v mng khng dy s nhanh chng thu li vn v sinh li.

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Hnh 9 : Bng chi ph u t WiFi

Hnh 10: Thit b Access Point

Hnh 11: Card mng h tr Mng khng dy s dng cho PC v Laptop

7. Cc tiu chun p dng cho mng khng dy :Gii php tng th cho mng khng dy ca cc cng ty mng trn th gii da trn cc tiu

chun quc t, c chun ho, cho php cc thit b ca cc cc hng khc nhau c th lm

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vic vi nhau. Tnh bo mt v kh nng lm vic c tnh ton khi thit k mng v trin khaimng.

Hnh 12: 802.11b l chun cho mng Mng Wi-Fi

V Vin K S in v in t (IEEE) a ra tiu chun u tin 802.11 nh ngha

cho mng LAN khng dy. Mc d t lu h thng truyn d liu khng dy c ng dng,nhng tiu chun 802.11 m ca cho cc doanh nghip trin khai v s dng mng LAN khngdy trong cc to nh v gia cc to nh c khong cch gn nhau. K t khi IEEE 802.11 u tina vo ng dng vo nm 1997, IEEE khng ngng pht trin 802.11. Hn 50 nh cungcp a ra hng trm sn phm tng thch thng s 802.11.

Ngoi IEEE, cc t chc khc cng a ra cc tiu chun truyn thng khng dy. Chu uv Nht bn, cc cng ty truyn thng cng a ra cc tiu chun ring ca mnh cho cc ngdng nht nh. V d, IEEE 802.16 cng a ra cc tiu chun i vi mng khng dy cc khusiu th. Tuy nhin, tiu chun c ng dng ch yu vn l IEEE 802.11, trung bnh mi

thng 1,5 triu my s dng card LAN 802.11.Hin nay c rt nhiu nhn hiu nh 802.11a, 802.11b ang c cc hng s dng nn d b

nhm vi tiu chun 802.11 gc. Tuy nhin, th t cc ch ci khng ph hp vi th t m snphm c gii thiu. V d, cc sn phm 802.11b c a ra th trng vo nm 2000 v2001, trong khi cc sn phm 802.11a c a ra vo u nm 2002.

8. Gii thiu v WIMAX :Cng ngh WiMAX, da trn c t IEEE 802.16-2004, bn thn nhanh chng chng minh l

cng ngh ng vai tr ch o trong mng th khng dy bng rng c nh. Mng WiMAX c

nh, da trn giao din khng gian (air interface) ca chun IEEE 802.16-2004 l mt la chnmang li hiu qu kinh t hn so vi cc dch v truy nhp bng cp v DSL. Thng 12 nm 2005,IEEE thng qua c t 802.16e l phn b sung ca 802.16. Phn b sung ny thm vo nhng ctrng v nhng thuc tnh cn thit h tr cho kh nng di ng. Hin nay, vic nh ngha cchot ng h thng, cc cu hnh thc hin, cng nh kin trc mng cn thit thit lp nn mtmng WiMAX end-to-end ang c thc hin, v cc c t v h thng WiMAX Release-1 dkin s c hon thin trong nm 2006.

WiMAX di ng l gii php khng dy bng rng cho php hi t my di ng v mng bngrng c nh thng qua mt cng ngh truy nhp v tuyn bng rng chung v kin trc mng linh

hot. Giao din v tuyn trong WiMAX di ng chn s dng k thut a truy nhp phn chia theotn s trc giao OFDMA (Orthogonal Frequency Division Multiple Access) nhm nng cao hiu nga ng trong mi trng che chn NLOS (non-line-of-sight). Trong phn b sung IEEE 802.16e

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gii thiu k thut SOFDMA (Scalable OFDMA) h tr cc bng thng knh truyn nhiu mc t1.25 MHz n 20 MHz. Nhm k thut di ng (Mobile Technical Group MTG), thuc din nWiMAX, hin ang pht trin cc m t h thng WiMAX di ng bao gm cc c tnh bt buccng nh cc c tnh ty chn din n WiMAX thng qua. Cc m t ny cho php cc h thngdi ng c cu hnh da vo mt tp hp cc c tnh c s chung, bi vy m bo ranh gii vmt chc nng gia cc thit b u cui vi trm gc BS (base station). Mt s phn t trong cu

hnh trm gc l ty chn tng thm tnh mm do trong trin khai h thng, c th hoc ti u vdung lng h thng hoc ti u v vng ph. Cc c t WiMAX di ng Release-1 s bao gm ccknh c bng thng l 5, 7, 8.75 v 10 MHz ti cc di tn c cp php l 2.3 GHz, 2.5 GHz v 3.5GHz.

Hnh 13. c t h thng WiMAX di ng Release-1

H thng WiMAX di ng m ra kh nng phn chia nhiu mc (scalability) trong c cng nghtruy nhp v tuyn v kin trc mng, v vy cho php linh hot trong vic ty chn khi trin khaimng, cng nh cc li ch v mt dch v. Sau y l mt s c tnh ni bt ca WiMAX di ng:

Tc thng tin cao (High Data Rate): Vic kt hp k thut anten MIMO, cng vi vic

phi hp sp xp cc knh con linh hot, iu ch v m ha nng cao cho php cng nghWiMAX di ng c th cung cp tc download d liu ln nht ln n 63 Mbps trn 1sector, v tc upload d liu ln nht ln n 28 Mbps trn 1 sector trong knh 10MHz.

Cht lng dch v QoS (Quality of Service): Tin c s ca kin trc MAC IEEE802.16 l cht lng dch v. N nh ngha cc lung dch v c th sp xp cc im mdch v phn bit (DiffServ code points) hoc cc nhn lung MPLS thc hin IP trn cs QoS t cui n cui.

Scalability: Nn kinh t ton cu ang tng trng nhanh, ti nguyn ph tn cho thng tinv tuyn bng rng trn ton th gii c phn b khc nhau. Bi vy, cng ngh WiMAX

di ng c thit k cho php phn chia cc knh hot ng t bng tn 1.25 MHz n 20MHz nhm tun theo nhng yu cu thng thay i ca th gii, nhiu n lc ang ctin hnh t c s cn i ph tn trong thi gian di hn. iu ny cng cho phpcc nn kinh t khc nhau nhn thc c cc li ch nhiu kha cnh ca cng nghWiMAX di ng i vi nhng yu cu v mt a l ring bit ca h, chng hn vic cungcp kh nng kt ni Internet vng nng thn hay vic nng nng cao dung lng truynhp bng rng di ng khu vc th v khu vc ngoi .

Tnh bo mt (Security): c tnh bo mt trong WiMAX di ng l tt nht vi vic nhnthc trn c s giao thc EAP (Extensible Authentication Protocol), mt m ha nhn thc

trn c s AES-CCM (Advanced Encryption Standard Counter with Cipher blockchaining Message authentication code), CMAC v HMAC da vo cc chin lc bo vthng ip iu khin (control message).

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Tnh di ng (Mobility): Mobile WiMAX cung cp cc s chuyn giao ti u vi trnh hn 50 ms cho cc ng dng thi gian thc chng hn nh VoIP m khng lm gimcht lng dch v. Cc s qun l mm do m bo duy tr tnh bo mt trong sut qutrnh chuyn giao.

Trong khi hot ng thit lp chun cho Mobile WiMAX ang c tin hnh th nhng nh cung

cp thit b cng tch cc pht trin cc thit b tun theo c t WiMAX 802.16e. Vi kh nng snsng thng mi ha ca cc thit b tun theo c t Mobile WiMAX ( c d on trong mttng lai rt gn) v s ra i ca cc dch v WiBro (cng da vo 802.16e) trong nm nay ti HnQuc, t ra mt cu hi rng: bng cch no cng ngh Mobile WiMAX c lin quan v nh hngn bc tin ca cng ngh t ong 3G ? tr li cu hi ny cn thit phi c nhng hiu bit v cs cng ngh ca Mobile WiMAX cng nh v l trnh nng cp c k hoch ca h thng thng tin ding 3G.

9. Cc ng dng ca WiMAX

Tiu chun WiMAX c pht trin phc v cho mt phm vi rng cc ng dng, c th ctm tt trong hnh 14 sau y.

Da vo cc c tnh k thut v phn lp dch v, WiMAX thch hp cho h tr s lng ln cckch bn thng dng (usage scenarios). Mt s cc kch bn ny c lit k trong hnh 15 sau y,hnh ny cng cho bit cc c tnh k thut no ca WiMAX l then cht cho hot ng thnh cngca cc kch bn.

Hnh 14. Phn lp cc dch v WiMAX

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Hnh 15. Cc kch bn c s dng cho WiMAX

Cng ngh WiMAX s cch mng ha cch thc lin lc ca chng ta, cung cp s t do honton cho nhng ngi thng xuyn di chuyn, cho php h gi c kt ni vi thoi, s liu v ccdch v video. WiMAX s cho php chng ta i t nh ra xe hi, sau i n vn phng hay i n

bt c ni u, khng c bin gii.

a. Cellular Backhaul:

Th trng cho cc dch v mng t ong ngy cng tr nn cnh tranh. tn ti trong kinhdoanh, cc nh cung cp dch v di ng chc chn phi tm cc bin php nhm gim chi ph vnhnh. Cc chi ph backhaulcho cc nh cung cp mng t ong chim mt phn tng i trong ccchi ph nh k ca h. WiMAX c th cung cp cc lin kt im n im ln n bn knh 30 dm(50 km), vi kh nng v tc d liu c th h tr nhiu ng T1/E1. Cc nh cung cp mng vvy c th s dng thit b WiMAX ko li (backhaul) lu lng trm gc n trung tm chuynmch v vn hnh mng.

Lu lng trong mng t ong bao gm thoi v s liu, i vi nhng dng lu lng ny cc ctnh sn c ca WiMAX rt ph hp. Vic thu cc tin nghi backhault cc cng ty in thoini ht c th rt t, trong khi vic trin khai mt gii php cp quang s va t v va tn nhiuthi gian, iu ny c th c tc ng tiu cc n vic gii thiu dch v mi. Gii php khng dycho cung cp cellularbackhault khi c hiu qu v gi thnh khu vc nng thn v ngoi , v huht cc phin bn ca DSL v cng ngh cp khng th a ra nhng bng thng theo yu cu, c

bit l khi tin ln mng 3G.

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Hnh 16. Cellular Backhaul

b. Wireless Service Provider BackhaulCc nh cung cp dch v khng dy (Wireless Service Providers WSPs) dng cc thit b

WiMAX ko li (backhaul) lu lng t trm gc trong mng ca h, nh minh ha trn hnh 17sau y:

Hnh 17. Wireless Service Provider Backhaul

Cc mng truy nhp c th da vo WiFi, WiMAX hay bt k mt cng ngh truy nhp khng dyc quyn no khc. Nu mng truy nhp s dng thit b WiFi, ton b mng ca nh cung cp dch

v khng dy (WSP) s c xem l mt Hot Zone. V cc nh cung cp dch v khng dy thngthng ch cho thoi, s liu v video, nn c im v QoS sn c ca cng ngh WiMAX s gip

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u tin v ti u lu lng c backhaul. Thit b WiMAX c th nhanh chng trin khai, thuntin cho vic gii thiu mt mng cung cp dch v khng dy mi.

c. Cc mng ngn hng (Banking Networks)Cc ngn hng ln c th kt ni cc chi nhnh v cc khu vc t my ATM n tr s chnh ca

h thng qua mt mng WiMAX ring mang thoi, s liu v video. Cc ngn hng ny thng tri

ra trn mt khu vc rng ln v cn bng thng rng cng nh bo mt cao c th m bo ccgiao dch v d liu ca h.

Hnh 18. WiMAX cho mng ngn hng

Vic mt m ha d liu trong WiMAX mang li nhng lin kt bo mt tuyt vi. Tuy nhin, ccngn hng s rt cn bo mt cui n cui (end-to-end), chng hn c cung cp bi SSL, bov khi nhng xm nhp khng mong mun v cc thao tc i vi d liu ngn hng nhy cm.Vng ph rng v dung lng ln cho php ngn hng trung tm c th kt ni n mt lng lncc chi nhnh v cc khu vc t my ATM. Mng WiMAX cng cung cp kh nng co dn cao

cc lu lng d liu tc thp gia cc trung tm v cc my ATM c th cng tn ti vi ccgiao dch yu cu tc cao gia cc chi nhnh v trung tm. iu ny c th thc hin c bicht lng dch v WiMAX (WiMAX QoS), c s dng dnh ring cho ting ni (thoi giacc chi nhnh), s liu (cc giao dch ti chnh, email, Internet v Intranet) v lu lng video (gimst, CCTV).

C rt nhiu l do cc ngn hng c c mng ring ca h. Bn cnh vic loi b nhng chiph phi tr cho cc cng ty in thoi hng thng, iu ny s gip cho ngn hng c kh nng nhanhchng trin khai li mng ca h nu mt my ATM hay mt chi nhnh tm thi phi di chuyn. Viclp t dch v DSL hay cp s khng th nhanh chng v s khng cung cp bng thng yu cu cho

thng tin gia cc chi nhnh v ngn hng trung tm.

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d. Cc mng gio dc (Education Networks)

Trong gio dc c th s dng mng WiMAX kt ni cc trng hc v cc vn phng bntrong mt khu vc. Mt vi yu cu quan trng ca h thng mng trng hc l NLOS (Non Line-Of-Sight), bng thng rng (>15 Mbps), vng ph rng, im n im v im n a im.

Hnh 19. Mng WiMAX trong gio dcCc mng gio dc da trn WiMAX, vi vic h tr QoS, c th phn phi y cc yu cu

truyn thng bao gm ting ni thoi, d liu ( nh kt qu hc tp ca hc sinh), email, Internet vIntranet, dy hc t xa. Chng hn trn hnh 19 m t mt camera t ti trng hc B ang thu nhnv truyn trc tip mt bi ging n trng hc A, cho php s lng ln sinh vin c th cng thamgia 1 mn hc ca cng mt chuyn gia ti cng mt thi im.

e. An ton cng cng (Public Safety)Cc c quan nh cnh st, cha chy, tm kim v cu nn c th s dng mng WiMAX h

tr trong nhng trng hp khn cp.

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Hnh 20. WiMAX trong an ton cng cng

f. Lin lc trn bin (Offshore Communications)Cc nh sn xut du m v kh t cng c th s dng cc thit b WiMAX thc hin lin lc

t cc phng tin trn t lin n cc dn khoan, h tr cc hot ng t xa, tnh bo mt, vcc lin lc thng thng khc.

Hnh 20. WiMAX trong lin lc trn bin

g. Kt ni campus (Campus Connectivity)

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Hnh 21. Campus Connectivity

Cc vn phng ca chnh ph, cc hng thng mi ln, cc khu vc cng nghip, cc trung tmgiao thng, cc trng i hc v cao ng, c th s dng mng WiMAX kt ni nhiu v tr, khuvc hay cc vn phng trong vng hot ng ca h. cc h thng campus i hi dung lng d liuln, tr thp, vng ph rng v tnh bo mt cao.

h. Cc mng truy nhp WSP (Wireless Service Provider Access Network)Cc nh cung cp dch v khng dy (WSP) s dng mng WiMAX cung cp cc kt ni choc cc khch hng dn s v cc doanh nghip, c th c minh ha nh hnh v sau y:

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19/22

Hnh 23. Xy dng WiMAX vng nng thn

10. Nhng vn cn quan tm v ph tn ca Mobile WiMAX

tn dng nhng u im v li ch ca h thng Mobile WiMAX, vic phn b ph tn theokhi ln thng c a chung hn c. iu ny cho php h thng c trin khai ch TDD

vi cc knh truyn bng thng rng, ti s dng tn s linh hot v gim thiu vic km hiu quph tn do cc khong bo v (guard bands), cho php cng tn ti cc nh khai thc cnh nhau. Mthot ng quan trng khc cho din n WiMAX l cng tc vi cc t chc tiu chun trn th gii xc tin vic cp pht ph tn bng tn thp (


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11. Kt lun

Tp bo co trnh by mt cch tng quan v cng ngh mng khng dy (Wireless Network)v Mobile WiMAX, cung cp cu hnh hot ng c s nh nht da vo cc c t h thngRelease-1 ca WiMAX Forum, trnh by mt s ng dng tiu biu ca WiMAX. Ta thy MobileWiMAX c th cung cp dung lng ca knh truyn ln n hng chc megabit t mi trm gc,

vi cu hnh c phn chia bin gii. Bn cnh , mt s c tnh tin tin khc chng hn nh hthng anten thch nghi ci tin hot ng ca h thng cha c trnh by y.

Vi thng lng d liu ln cho php vic ghp knh hiu qu v tr truyn thp. Vi cc c tnhca mnh, WiMAX cho php cung cp cc dch v d liu bng rng bao gm d liu, lung video vVoIP vi cht lng dch v cao. Cu trc c kh nng co dn (scalability), dung lng d liu lnv chi ph trin khai lp t thp gip cho Mobile WiMAX tr thnh mt gii php dn u cho ccdch v bng rng khng dy.

Vi cc c im v kh nng hot ng gip Mobile WiMAX tr thnh mt gii php y hpdn cho cc dch v khng dy bng rng hiu qu cao v chi ph thp. Mobile WiMAX hin ang

trn l trnh xc nh th trng ton cu thng qua cng ngh truy nhp v tuyn bng rng chung vkin trc mng linh hot. Cng ngh ny da vo cc giao din chun m c pht trin vi gn 400cng ty phn phi v iu chnh cc c t h thng t nn mng cho vic chp nhn ca thtrng ton cu.

Ti Vit Nam, B Bu chnh Vin thng va trao giy php cung cp th nghim dch v WiMaxc nh cho 4 doanh nghip trong nc gm: Viettel, VTC, VNPT v FPT Telecom. Sau 12 thng,B s la chn 3 nh cung cp chnh thc mng bng rng khng dy. Cc doanh nghip s c cpdi tn t 3,3 GHz n 3,4 GHz dnh cho dch v WiMAX c nh, vi tiu chun c t chcchuyn ngnh ca Lin Hp Quc v lnh vc vin thng l ITU thng qua nm 2004 (802.16

version D).Hin ti Vit Nam ch c th tin hnh th nghim dch v WiMax c nh v cng ngh di ng

cn rt mi (k c trn th gii) nn cha c cc thit b cho loi hnh ny. Khi thi gian th nghimkt thc, da vo cc tiu ch nh cht lng dch v, ti chnh ca mnh, 4 doanh nghip trn s phiu thu gii tn c th c tr thnh nh cung cp dch v chnh thc. iu ny nhm chun bcho vic gia nhp WTO v khi Vit Nam gia nhp WTO chng ta cn phi bnh ng vi th gii bnngoi, hn na gii tn WiMax l mt ti nguyn quc gia.

--- oOo ---

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DANH MC CC HNH V

Hnh 1: Cu hnh multicell in hnh s dng backbone LAN hu tuyn...............................................4

Hnh 2: Cc phng thc cu hnh Aironet Accesspoint.........................................................................4

Hnh 3: Cu hnh im AP lm chc nng repeater.................................................................................5

Hnh 4: AP thc hin chia ti (Load Balacing).........................................................................................5Hnh 5: Kh nng dch chuyn tc truyn dn ...................................................................................5

m bo duy tr kt ni trong mng khng dy........................................................................................5

Hnh 6: Nhng tnh nng vt tri ca Aironet.......................................................................................6

Hnh 7: Nguyn l hot ng ca Access Point.......................................................................................6

Hnh 8: Microcell vi Access Point..........................................................................................................7

Hnh 9 : Bng chi ph u t WiFi............................................................................................................8

Hnh 10: Thit b Access Point.................................................................................................................8Hnh 11: Card mng h tr Mng khng dy s dng cho PC v Laptop..............................................8

Hnh 12: 802.11b l chun cho mng Mng Wi-Fi..................................................................................9

Hnh 13. c t h thng WiMAX di ng Release-1...........................................................................10

Hnh 14. Phn lp cc dch v WiMAX.................................................................................................11

Hnh 15. Cc kch bn c s dng cho WiMAX................................................................................12

Hnh 16. Cellular Backhaul.....................................................................................................................13

Hnh 17. Wireless Service Provider Backhaul........................................................................................13

Hnh 18. WiMAX cho mng ngn hng.................................................................................................14

Hnh 19. Mng WiMAX trong gio dc.................................................................................................15

Hnh 20. WiMAX trong an ton cng cng............................................................................................16

Hnh 20. WiMAX trong lin lc trn bin..............................................................................................16

Hnh 21. Campus Connectivity...............................................................................................................17

Hnh 22. Mng truy nhp ca cc nh cung cp dch v khng dy......................................................18

Hnh 23. Xy dng WiMAX vng nng thn.....................................................................................19

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MC LC

1. Th no l khng dy?...........................................................................................................................3

2. Khi nim Wi-Fi v WiMax ?...............................................................................................................3

3. Ti sao li s dng mng khng dy?...................................................................................................3

4. Mng khng dy hot ng nh th no?............................................................................................65. i tng s dng mng khng dy l ai?...........................................................................................7

6. Chi ph u t cho mng khng dy :...................................................................................................7

7. Cc tiu chun p dng cho mng khng dy :....................................................................................8

8. Gii thiu v WIMAX :........................................................................................................................9

9. Cc ng dng ca WiMAX.................................................................................................................11

10. Nhng vn cn quan tm v ph tn ca Mobile WiMAX.........................................................19

11. Kt lun..............................................................................................................................................20

de tai tim hieu cong nghe mang khong day va mobile wimax

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