Luận văn truyền thông tin và những ứng dụng của mạng vanet

Nhu co the thiy tfr danh sich 6 tan etc ring twig, ky thuat vi vie khia cunh kink to xi hOi, linh Arc mg dung xe vi cic Ong nghe lien mpg dua tren ding nghe tren mOt no lirc lien nginh

BO GIAO DVC DAO TAO TRIAING DAI HQC THANG LONG

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CHUYEN BE TOT NGHIVI

TRUYEN THONG TIN VA NIIING irNG

D1VNG CUA MANG VANET

GM() vial' huirng din : ThS HOANG TRQNG MINH Sinh vien air hit'n : NGUYEN VAN CONG

HA NO! - 2013

MVC LTC

2.2.2 Ccic hf that' Ig dinhvi nhtf Li mOt nguiejn thong tin 19

3.2.2 Kit not 46

3.5.2 Cc c ban phcir thcio cho kip h9p dir lieu trong VANET 58

DANH MIJC IliNH ANH, BANG BIEU

Wnh 1.3 Vi dy h§ thing the nghi§m tgi Michigan (2008) 12 Bing 1.1 I3in di ctia VSC-A eng dgng an town vi kich bin cic vy tai ngn

Hinh 2.3 Tang him tOc (10 alit xe teen mlii phan dogn trong SOTIS 33

Ifinh 2.7 Thivi gian di Tour Eiffel den Arc de Triomphe 42 Hinh 2.8 M§t mting luid duirng phan clip trail tilting 43

Hinh 3.2 Phi bien de lieu bing cich se dyng cic chuii vi xe di dOng 48 Hinh 3.3 Anh hir&ng cult cic don vi ben ii throng 49 Hinh 3.4 Phan phiSi cic thiet bi ngang hing teen mOi phin doin duirng 54 Hinh 3.5 The h§ vie how nhit cis tip hip phic thio FM 58

CHUONG 1 Tang quan vi he tilting mang Vanet

Ltla MO DAU Ngay nay voi xu the ph& trien mph me ve tong nghe thong tin, dien tai van thong ket hqp v6i sq da clang va phong phd ye phuong tien k3 thuai da tao nen nhung hinh thai phat trien mai nham phuc vu cho den song con ngu6i Thong tin lien lac duqc m6 rung v6i nhitng rinh vqc mai hira hen nhieu sq phat trien Mang di dung thy bien trong xe hai cling la mOt rinh vqc dang duqc cac nu6c phat trien nghien ciru va dua vao sir dung nhi ► dua lei nhfang hieu qui, nhlang diem nhin m6i trong bu6c phat then

cua xe hai Be c6 the hieu has ve sir ph& trien, nhung buem tien cilia rinh vqc nay tOi mu6n giai thieu t6ng quan ye nhung khai niem, t6ng quan ve m8 hinh by thong cling nhu la ntang cong nghe duqc sir ch,mg trong m8 hinh mpg trong mpg di dOng thy bien cho xe hai (VANET) VANET (Vehicular Ad-hoc Network) la mOt (rug dung mang nhu the 1)6 11 mOt he thong mpg s(r dung cac giao tiip khOng day phan tan gift nhieu diem truy c#p Ichic nhau ma khemg can ten bit dr mOt cc; s6 ha ding c6 djnh lac) Bit cu thiet bj cam tay vii co djnh nio nhu dien thoai di dOng, laptop, may nhin tin, cac tram v8 tuyen ca so deu c6 the la mOt kenh thong tin trong mang VANET tao thimh mpg town ciu, rung khip mqi nai Cic thiet bj nay c6 the tich hqp vao cac d6i tuqng di chuyen (xe cu, tau thuyen, ) ho#c tl#t co djnh o cac diem khien cho viec truyen thong ce the dies ra o mqi lfic, mqi nai M8i phuang den tham gia giao thong (duqc tich hqp mOt thiet bj c6 khi Wing kit n6i day) lit( thinh mOt nut ciia mpg

Bao cio bao gam ba chirong:

Chuang 1: Glen thieu chung ve he thong Vanet va cac nguyen tic ca ban va

thich thirc ctla VANET, trinh bay mOt ljch sir ngin gun cac hog dOng cilia VANET Chuang 2: M8 to cac phuong phap de ph6 Wen thong tin va t#p Nip trong VANET can thiet de h8 trq cac img dung hieu qui va tien lqi

Chuang 3: Duqc xay dqng tree chuang 2 va tip trung vao cac img dung "Meng

an tan" do d6 muc tieu chi yeti la hieu qui va tien lgi

MOc lqc nghien ciru de hall thanh chuyen de cim minh, nhung do !den thirc va th&i gian con hp chi nen trong chuyen de t8i khang tranh kh6i nhfkng thieu set Toi rat mong nhon duqc cac d6ng g6p, nh#n xet tir phia flay co va cac ban

CuOi cling t8i xin chfin thimh cam an sir huong din va taco dieu kien ctla thiy Holing Trong Minh trong su6t qua trinh t8i lam bito c.ao nay!

CHUONG 1 Ting quan ver ha th6ng mang Vanet

CHU•ONG 1 TONG QUAN Vt HE THONG MANG VANET

1.1 GIO1 THIEU CHUNG Vt MANG VANET

1.1.1 Khdi niflm

VANET (VEHICULAR AD-HOC NETWORKS) li mpg trong da cic xe

(vehicule) se duqc trang bj thiet bj thu/phit, chang se ter thinh cic node nhu trong

mpg ad-hoc Cic xe se lien lac vai nhau (Car-to-Car Communication), hay M2M

(machine-to-machine communication) de chia se thong tin lin nhau ThOng tin ye

traffic, ye tinh trang kit xe, thong tin ye tai not giao thong, nguy hiem can trinh M0

chile xe ding c6 the trb thinh mOt Relay Node a chuyen tii th8ng tin cho xe

khic VANET sfr chum chuin Wifi 802.11

1.1.2 Tgi sao eó h? thong Vanet?

— Cong nghiap xe ngiy ding phit trier

—S6 vu tai non giao thong, On tic ngiy tang tang

—Cic phuang flan thiet bj phut vu cho giao thong chtra tai uu

1.2 NGUYEN TAC CO BAN VA MACH Marc

Khii niem co bin cda VANET la khang phi= tap: thuc thi tram deg nghe

WLAN dian rang vi khong qui dit, tart li ket n6i giva cic may tinh vii nhau hoot vii

intemet, vi vai nhieu cii lien no duqc ip dung len xe cO Diu lien, thong to xem x&

den co hOi Neu cic phuong den c6 the truyen thong tnrc tap vii nhau vi v6i co so ha

Ling, meo hinh hob toin moi cho nheng (mg clang an toin cba phuang den 06 the se

duqc hinh thinh Thtl hai, nheng thich thac mad da thrqc too ra Uri phuong tian tee do)

cao vi mad trubng tic dOng llrc lan Thir ba, nheng yeu ciu can phii c6 Ye an loin d6i

yeti cic frog dung mad, bao gim nheng 10 vqng mad cho phin phii gei tin cao vi

dO trg gei tin thip Han naa, phin (mg mb flint cM khich hang vi su gin sit caa ha

thing giim sit dem lei 10 vqng cao ye an ninh vi sir rieng tut

Them chi ngiy nay, chiec xe too ra vi phial tick luqng bfm de lieu, mac thl de

lieu nay thubng china trong mOt chi& xe duy nhit ce VANET, dim nhin (kha

Whig nh$n biet xung quanh) cue cic phuang tian giao thong vi cue lii ACC duqc tang

len ding Ice Truyen thong VANET c6 the thuc hian true till) gala cic xe nhu Owen

th8ng "mOt buoc", hoot phuang tian ce the truyen lai bin tin, do da cho phdp truyen

thong "da Woe De tang yang phtl sang hoc dO ben yang cult truyen thong, chuyen

tie') lc ben thrtmg c6 the duqc trien khai Co so ha tang ben throng clang c6 the duvc sfr

dung nhu mOt deg vio internet vi do da de lieu vi th8ng tin net cinh c6 the duqc

thu thap, luu Ire vi "6 mqi nor, vi du ca so ha ling mang cue coag nghe ditat

town dim may sip tad

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CHISONG 1 Tang quan ve he thong mung Vanet

N6 dim bao ring mpg lien kit gift cic xe se thfic diy manh me b6i su phong phi caa cic Ung dung co the dugs kich hoot Truoc het, cic ting dt,mg an toan chb

dOng, tirc la cic ting dung phong ch6ng tai nun se duqc hiding lqi mOt cich true dip tfr

truyin thong Thir hai, bang cich thu thilp dtt lieu twig thii giao &Ong ter mOt yang rung han, luu luqng giao thong c6 the dirge cal thief', thstri gian di chuyin c6 the duqc giim cling nhtr nheng lchi thii hY cic phuang lien Nhu n6 di duqc ghi chinh xic nhu

cic nguyen 1 cult he th6ng giao th8ng thong minh (Intelligent Transportation System World Congress) nam 2008: Tiet kiem th6i gian

Cic 16p (mg dung "an tan" vi "hien qui" c6 the duqc sfr dung de phan loci cdc

Ung dung dlra tren mix dich chinh cia chimg Tuy nhien, cic khia can't an toile vi hieu qui khong the quan niem nhu cic tinh Wing tech r6i hoiln town R8 tang, tai min

xe c6 the din den tic nghen giao thong MOt bin tin th8ng bio mOt vu tai non ce the duqc xem nhu la mOt thong bio an town * diem quan sit caa xe gin d6 Ban tin Wang

tu c6 the duqc nhin cic phuong lien 8 xa han nhu mOt diu veto de tinh toin mOt 10 trinh thay the trong mOt (mg dung hieu qui giao thong

Ifinh 1.1 Bilu (IS minh has cdc cdnh bdo nguy hiim

Trong khii niem don giin, thiet ke vi tan khai cic VANET la met luc kq

diy thich thirc ve ky thust va kinh to Mich thirc chinh ve ky thuUt bao g6m cic vin

de sau:

— Cie Sc il dam c6 ham cda kenh v8 twin dien Cic kich ban hien nay mia VANET vbi nhieu die diem khong thu0n lqi cho vies phit trien truyen th8ng khong diy, vi du: nhieu doi tuqng phin inh co the lam suy giam dO mph vi chit luqng ctia song tin hieu nhen duqc Ngoai ra, do tinh di dOns cia cic dii

CHISONG 1 TOng quan ve hg thong mong Vanet

trung xung quash ho#c chting tv gfri vi tv nkftn, hilt' Ong mb din phii duqc dua vio sv tinh toin

—Thies mOt sv quin trung trvc tory& vi don vj phOi bqp Vilc sir dtmg ding bing vi hilu qui bang thong mkt kenh lchang day li mOt nhilm vp

kh6 khan trong mOt mong ur t6 chrrc vi phan cep hoin toin Vi$c thieu mOt thvc the c6 khi Wing ding bO h6a vi quip cic sv ki/n truyen tid cara cic of khic nhau co the din den sir dung kenh kern hilu qui vi din den s6 hrqng lon cic vv va ch?m g6i tin

—Mb di ding cao, yen khi Ring mfr ring, vi sw da ding cast Min kiln mdi trnimg Nheng thich th(rc cia mOt mong tg t6 clac plan cep duqc die bilt nhin manh den t6c dO cao Tinh di dOng cao li mOt thich thirc cho cic thuig toin t6i uu 1#p nhim s6r dung tot ban bang thong kenh hoc sb dung cic tuyen dutmg duqc dinh nghTa tru6c de chuyen tiep thong tin

—An ninh vi nhu cis rieng hr vi cfc m6i plan tam C6 mOt thich thirc ve can d6i gifts nhu ciu ve bio m#t vi tinh rieng tu MOt mkit, ben nh(in mu6n dim bio ring c6 the tin liking ngu6n thong tin Wit khic, sir tin luting d6 c6 the mau than voi cic yeu ciu rieng to cfia ben gtli

—Tien chain boa so limb ding C6 mOt nhu ceu cho truyin thong tieu chuin cho phep VANET lim vile qua cic kieu khic nhau vi cic chuin caa OEM Tuy nhien, chic chin ring OEM se mu6n too ra vii sv kbic hilt v6i cling nghl VANET Nhung raw tieu niy li c6 ye se khi kh6 khan

Mich thfrc chink ye mat klub ti xi

—Phan tich vi xic dish &Nov cic lqi ich cult VANET cho an toils giao thong

vi hien qua vin tii Cho den nay, rit it vile da duqc thvc hi¢n de dinh gia tic dung c6a VANET nhu mOt ngu6n thong tin ve hinh vi lii xe Re ring, nhung thich thirc lien quan trong vile giii quyet vin de dinh gii tic ding li m8 hinh c6a cic khia conh lien quan den yeti t6 con ngutri

—Phan tich vi xic dinh thrqc dic m6i (plan he chi phi - lqi lick adia VANET

Do thieu cic nghien ciru ye lqi ich c6a VANET, v#y plan tich chi phi - lqi ich kh6 ce the duqc thvc hiOn Chien luqc trien khai thiet ke cho load hinh VANET li kitting dra tren mOt cc s6 141 tong hoc mOt nhtt cung cop dich vp

nio Vile thiet bj VANET ce dirge hay kh8ng con phv thuOc vio cic d6i tic

truyen thong, cic hi thong mong hiln thOi c6 the h8 trq duqc hay khOng

—Nhing VANET trong kJ& trac hi thong giao thing thing minh VANET

0 la mOt phlin cua mOt hi thong giao thong thong minh noi mi Wing yes t6

CHUt5NG 1 TOng quan ve he thong mpg Vanet

hieu khic nhau COng nhu vay, giao thong ci nhan vi Ong cling phii duac nim trong tii khoin trong mOt kiln cich chung Bei vay, he thing hqp tic Nit sir cin duqc phit triin

Nhu co the thiy tfr danh sich 6 tan etc ring (twig, ky thuat vi vie khia cunh kink

to xi hOi, linh Arc (mg dung xe vi cic Ong nghe lien mpg dua tren ding nghe tren mOt no lirc lien nginh trong truyin thong vi mang, thiet bj dien ter tong xe, quin vi van hinh throng b0, cling cep cic th8ng tin vi dick vv Do de VANET ce the duqc

xem nhu li mOt phin quan tong cia he thing giao th8ng dieing minh (Intelligent Transportation Systems) (ITS)

Trong 'chi nhiiu du in khic nhau da thio luan chi& luqc tan lchai oho VANET, cic nghien c(ru chi yeti giii quyit nhitng thich thee ky thuat Hien nay, mOt sir thay

dii to rich dip can "ter dm% led" co dien Bing cich tap can "te tren xuong" Ly tueng nhit, ci hai phuang phip tiip can cutii ring se gap nhau• nhang gi duqc goi li mOt yeu ciu cho viec tan khai mang lui lqi ich co the duqc hi trq bOi nhing tier b0 cong nghe

1.3 LOCH sir VA skr PHAT MIEN CUA VANET

Lich sir cea viec sir dung song v8 tuyin vi hing ngoai cho truyin thong gifts xe vei xe vi xe vei ben dueng gin lien vei sir phit trim ctia 14 thing giao thong th8ng

minh Nhu them khio trong Shladover vi tong Lasky vi Ravani, cic khii niem ca

ban oda tu dung Ma dueng b0 nhu viec se dung the ky thuat truyin %Ong vi dieu Ichien di giao thong duting b0 an tan, hieu qui vi than thien vei mOi truing

Sau de, vac cam' nheng am 1960, he thing tu dOng hes dating b0 dva tren song v8 tuyin duqc phit triin vi cheng minh Ki hY do, co rat nhiiu de lieu dugs quan sit: Chi di chinh li an tan, hieu qui vi than thien voi mOi trubng, tong tam lien tuc thay doi theo thin gian Vi du, trong thei gian diu he thing hueng din tuyin dueng da

duqc dieu tra Sau do, he thing thu phi, nghien ciru lii xe tu dOng tre nen ph6 ban Nghien ciru vi phit trier o khu vuc khic nhau, chi yiu 6 my, Nhat Bin, vi Chau Au,

mi can o cic nai khic tren the giOi cing co anh huong l>e tii de duqc dinh diu bei sir tap trong 'chic nhau cia 8 t8 vi cic cling ding giao thong van tii

MOt chi di nhit quin theo thei gian li "ngan sich - ai se tri phi?" MOt mat, nginh cong nghiep 8 to vi dien ter nghi ng6 cic ca se hu tang dog rung cho he thing dueng cao tic thong minh (Intelligent Vehicle - Highway Systems) (IVHS) se khong bao gib thich hien thuc Mat khic, cic dan vi chi quin dueng cao tic nghi nge lieu tong nghe IVHS se cung cep giii phip thuc ti cho cic vin di dueng cao tic thqc sir Trong phin du& day, se di cap din cic hoot dung buec tien quan tang lien quan din VANET

CHISONG 1 Ting quan ve hg th6ng mane Vanet

1.3.1 TIr &iu din giea nhihog nano 1990

O My, mot ho thing hutmg din &Ong dien to (Electronic Route-Guidance System) (ERGS) d8 duqc de xuit trong Rosen: "He thing djnh hutmg diem den Ngutri dieu khien xe nhap vito mOt mA, dal dien cho dja chi dich c0a minh vao thiit bj xe Sau d6 khi phuang tien tien den mil diem giao ma dich duqc chuyin den atic tram ben dtrong tai de n6 duqc giai ma, theo mOt chtrong trinh ltru tat, va mOt chi din dinh tuyen duqc truyen lai cho chiec xe."

He thing truyen thong sbr dung tin só 170 kHz clOng Ang-ten yang duqc lip d*t tai nut giao %Ong va gin vao phia sau caa xe Tic dO truyin catlieu bao cao la 2000 bit/gialy Nhung nhang n8 luc ERGS bj chim dirt do cac ca so hu tang ben duong dit tien

Tai Nh.t Ban, he thing dieu lchien giao thong 8 te tan dien (CACS) duqc thuc hien 1973-1979 do ca quan deg nghiep Khoa hac va C8ng nghe dui BO Thucmg mai

va C8ng nghiep Quic ti (MITI) Muc lieu cua CACS duqc trinh bay trong Kawashima vin con hien luc sau han 30 Min:

—Giant un tic giao thong dubng Xi;

—Giam khi thai gay ra bbd su tic nghen giao thong;

—Phong ngta tai non;

—Nang cao vai fro cling ding va xa hOi cila 8 t6

Be flat duqc muc lieu nay, bin muc tieu thuat di duqc de ra:

— Huang din lai xe di then cac tuyin chgmg thich hqp nhit de tranh On tic va 8 nhiim khOng khi;

— Cung cep th8ng tin lieu ich de hi trq lai xe an town;

—Uu tien cac xe ding cling hotic truing hap khan cep;

—Cung cap thong tin kip thin cho ngutri lai trong throng hqp khin cap

Cac du an CACS ding duqc thuc hien thi diem vei 98 thin bi ben dtrong A 330

xe tht? nghiem (Nakahara vi Yumoto) Dii vai truyen thong ben throng thi xe, cac tram ben dubng str dung Ang ten Ong con cac phucmg tien giao thong sa dung Ang-ten 101 cho tic dO truyen tai ctia bao cao la 4.8 kbps

Tai chat' Au, de an Prometheus (chuang trinh giao &Mg chAu Au vai gia cao nhit chua mang lui hien qua vi an tan) ichoi xutmg vao nom 1986 va ra mit nom

1988 c6 * nghlit kich thick host ding nghien dru va phat tan trong rah vuc deg nghe th6ng tin va twin th8ng di dung cho xe c6 ding ca va nhang con duOng Prometheus di drat hi trq boi 19 quic gia chau Au vb cac Oy ban cling ding Chau

CHYONG 1 Ten quan ye he thOng mpg Vanet

Au (Walker nam 1992; Williams 1988) Nhu vi du neu trong Gillan, Prometheus di duqc t6 chi= tai cac he thong khhc nhau, bao g6m:

— PRO-CAR: lai xe trq bb i he thong dien tb;

— PRO-NET: truyen thong gitta xe yeti xe;

— PRO-ROAD: truyen thong gifts xe va m8i trutmg

Trong Prometheus, truyin th8ng gitta xe va xe (long met vai Ire n6i b#1: bao cao cat' Dabbous va Huitema vin c6 the duqc chu Sr cep nh#t trong nhieu khia canh Dabbous va Huitema phan Lich cac yeu ciu truyen thong Ara tren ldch ban dien hhih, vi

du cho chin ttp that' &Si lin &Ong Gii sfr mOt chain luqc quing ba dinh kjr va you ciu

dO chinh xAc khoing cach va chum, ho chi ra ring met danh gin th#n tong t6c de truyin ban tin tang thai cda mii xe se djnh ki gfri 20 phien truyen tren mil giay ciut m6i Dabbous va Huitema cang cho thiy cac neu gam di you clu ve de chink xlic khoang cach va chum va gioi thieu cac phuang phap du dam 05 the lam Ohm ding ke s6 lin you ceu truyen tai DA duqc tip trung tren clic he thong hog ding 6 bang tin 60 GHz

Su quan tam trong truyin thong gifts xe v6i xe tilp top 6 Nh#t Bin va my cuoc khao sit trong Kawashima trich din hai bin bio cao thu#t cis JSK hiep hOi cling nghe dien tfr cho lai xe va 8 to (Association of Electronic Technology for Automobile Traffic and Driving) duqc xuit ban Nilo nam 1986 va 1988, Wong Ong, lc& qua thil nghiem truyen th8ng gitta xe vai xe 6 My, nhu duqc nett trong Shladover, mOt trinh dieu khien chinh xuit hien de to ding lai xe va nhieu phuong den Trong Sachs va Varaiya, cac you cau va thong se ky thuit de truyin th8ng giita xe v6i xe vi gitta xe yeti thiet bi ben diking de cho xe to gong duqc trinh biy Tong kit du in hoot gag cha thtri ki nay tai My, Chau Au, va NIgit Ban cling nhu nhin ve twang lai doi vai he

thong throng truyen cao tec th8ng minh (Intelligent Vehicle-Highway Systems) &gm

dua ra beri Jurgen

1.3.2 Tw min nhang nans 1990 din nay

Nth sau cha nhiang nam 1990 la cet mec quan tong ghi lai met su thay doi 16n Kit qua An ttrong ye trinh dieu khien hqp tic dOc 1#p duqc chimg minh tai San Diego, bin gioi thieu cOa cac dei tac California cho nang cao vfn tIi va doting cao tec

(Advanced Transit and Highways) (PATH) vho nam 1997, giai dap 2 giai thieu ye nang cao tinh an town phucmg den (Advanced Safety Vehicle) (ASV) vho Mtn 2000 tai

thanh phi Tsukuba, Nh#t Bin, va trong du in PROMOTE CHAUFFEUR European TOp trung sau de chuyen tfr lai xe kit hop to quan sang he thong trq trinh dieu

khien hqp tic Ti My cac sang kill phucmg tien thong minh (Intelligent Vehicle Initiative) (NI) trong nhiang atm 1998-2005 (Hartman va Strasser ) t#p trung vao an

tohn hieu qui hqp tac Tai chau Au, cac du in CarTalk vi FleetNet cba Franz nghien

CHUONG 1 Tong quan ye he thong mong Vanet

ciru ding nghe va cac (mg dung he trq hqp tic Idi xe T31 NhUt Ban, giai don 3 caa dg

an tiring cep an tan phuang lien cling th6a then vai tr6 cult truyin thong lien phucmg tien de he trq hqp tic lai xe

Sq thay del tin 96: 5.9 GHz DSRC

IChai niem ve VANET di bi inh huong bei nhtIng lien b0 trong Ong nghe va tieu chuitt hea ke tfr gitta nhting nam 1990 Nim 1999 la mOt "sir thay dei tan se" xay ra khi 1:Jy ban Truyin thong lien bang my phis be bang thong 75 MHz cua did 5,9 GHz cho truyin thong tam ngin chuyen dung (Dedicated Short-Range Communication)

(DSRC).Thuet net truyin th8ng tam ngin chuyen dung (Dedicated Short-Range Communication) di duqc sir dung nhu mOt tht4t net tuang 14p ve Ong nghe cho =yen thong khong day tam ngin gifts cac xe va ca s8 ho ting

MOt rim sau, ASTM International thinh lep met nh6m lam viec de ghat trien cac yeu caw ve tieu chum DSRC tuang (mg Trong nim 2001, Uy ban tieu chuin 17.51 cut ASTM chcm IEEE 802.11a la c8ng nghe v8 tuyen nen tang cho DSRC Cac lieu chitin Wang ting di duqc dua ra trong nam 2002 vi sM di vac nam 2003 (ASTM E2213-03 2003) Cac ap lqc phai sir dung kenh duqc giao va tinh kha thi ¢ua cac deg nghe Ara chuin IEEE 802.11a thi lam tang ding ke cac hoot dung nghien cuu va phat tan DUc biet, cling deng mong di dOng quan tam den chili de caa ming luoi xe di duqc hei sink Nim 2004, IEEE bit ttiu deg viec stla 661802.11p va tieu chuin truy cUp lchong day trong m8i tramg xe CO (Wireless Access in Vehicular Environments)

(WAVE) dqa tren cac lieu chitin ASTM (Jiang va Delgrossi) Dir an truyin thong an town phucmg On (Vehicle Safety Communications) (VSC) duqc he trq ben to ch(rc do luting an town va ch?m (Crash Avoidance Metrics Partnership) (CAMP), cuc quan trj

duting cao tec lien bang My (US Federal Highway Administration) (FHWA), va ban quart ly an town giao th8ng dtrong bO My (US National Highway D•ajjic Safety Administration) (NHTSA) khao sat ccIng nghe DSRC 5.9 GHz dang n6i trong nhUng nam 2002 den flint 2004 va ket luin ring phuang phalp dip clura tren chuin IFFF,

802.11a se c6 the M trq hiu hit cac (mg dung an town ma VSC di chcm Cac bao cao cu6i cling mkt VSC (VSC 2006), cOng dun ra met ckh rO rang nhttng thach &tic cna truyen th8ng c6 dO trg thep vi if& sin sing cao colt cac kenh vo tuyen cling nhu cac yin de lien quan den Icha fling caa kenh nei chung Nam 2004, HOi thao qu6c to ACM diu lien ve mong xe CO bit djnh (Vehicular Ad Hoc Networks) di din ra Philadelphia, sau de thuUt net "VANET" di duqc det ra

Cac dy in Mtn tai vi host dung

Trong phin nay, di cep mOt cai nhin teng quan kh8ng day du ye cac dir an VANET dang dign ra va cac hoot dung 6 chau Au, Nht Ban, va Hoa Ky Met cal nhin

CHISONG 1 'fling quan ve he thong mung Vanet

t6ng quan cho they mirc dO hoot dung cao trong linh vvc nghien cuu vi phit tan VANET vi de chirng minh li cic deg nghe truyin thong khong day duqc bio dim li

ca so cua lieu het cic hout Ong cila VANET tren toin the gioi (hinh 1.2)

Trong chuang trinh khung se 6 cua EU, ben dv in duqc bit dau trong cic linh Arc ce lien quan den VANET: COOPERS, CVIS, PReVENT, vi SAFESPOT Dv in

he thong hqp tic cho an toil) duOng b0 th8ng minh (Intelligent Road Safety)

(COOPERS, 2006-10) t#p trung vio img dung vin thong tien tier cho quin hqp tic giao th8ng Tir gee go truyin thong, th8ng tin ch6 yeu lit truyin thong gitta xe vi cic from ben throng vi s>3r dung lieu chain CALM nhu giao dien truyin thong hung ngoui CALM CALM li ISO TC 204 (ITS) Working Group 16 (Communication) trong "giao dien kheong day lien tic cho khoing cich tittnmg binh den" CALM nham muc dich trq truyin th8ng lien tic cho xe bang cich sfr dung cic phuang tien truyen thong khic nhau vi cic giao dien truyen th8ng Cic dv in he thong co ser hit tang phuang tien hqp tic (Cooperative Vehicle-Infrastructure Systems) (CVIS, 2006-10) di tip trung vio phit trier vi th(r nghiem trivet' thOng cfia phuang tien vol ca s8 hu tang vi theo lieu chat' CALM CVIS lam cho vies sir dung WAVE WEE 802.11 c6 lien quan giao dien duqc hieu lii giao dien M5 (d6i voi "Microwave 5 GHz) trong khuen kh6 CALM Dv in SAFESPOT (2006-10) nhim muc dich thiet ke hu thong hqp tic xi cho

an tan &gong bto dva truyen th8ng gitta xe Wei xe vi xe vOi ca sO hu tang Cic deg nghe truyin th8ng duqc s>Sr dung trong dv an SAFESPOT li IEEE 802.11a/p Dv in PReVENT (2006-08) giii guy& phit tan cic Ong dung an toin dv plitong vi c8ng nghe trong dv an PReVENT tick hqp, cic dv in nho WILLWARN (Wireless Local Danger Warning) t#p tning vio cic cho de call truyin th8ng gift xe v6ri xe vi gitta xe yeti ca so hu tang He thong WILLWARN dva tren IEEE 802.11a/p vi di sir dung nen tang truyin thong phit trien b Dirc do; in Network on Wheels (NOW) Ngoii ra, dv in

Secure Vehicular Communication (SeVeCom, 2006 din nem 2008) di duqc dinh rieng de xic djnh cic mei de do vi quy djnh cu the phuang phip vi Icien trac de dam bio truyen thong xe Icheng day

CHIANG 1 Toting quan ve 4 thOng mpg Vanet

Hinh 1.2 MS hinh tong quan 4 cdc gitii phdp VANET

Hien nay, theo chucmg trinh 7 khung, huang ten cac thtl nghiem rinh voc duqc tai trqi, dac biet 11 do in PRE-DRIVE-C2X dang chitin 1)1 xay dung cac kh8i an that cho thir nghiem thimh c8ng hoot dung cua VANET a chAu Au

TO Nhat Bin, mOt tieu chwin a xe ca tilt truyin thong voi co at ha tang da duqc c8ng biS Mtn 2001 vi goi la "Dedicated Short-Range Communication System" (ARIB 001) He thong hoot dung 0 an s6 5,8 GHz, duqc doa tren da truy nhap phin chia theo thbi gian (TDMA) vi trong phom vi 30m Moc Bich chinh cua he thOng la stt cb,mg trong vier thu phi dies fil nhtmg da duqc tan khai de h8 trq cho cac dich vo 'chic (ARIB 2004) Trong nam 2008, tren 20 trieu don vi bo mach din ter da duqc trian khai

Ti Nhat Bin, dim tren so thanh c8ng tren he thteg DSRC 5.8 GHz vi truyan

CHUONG 1 Tang quan ve he thong mong Vanet

dang tham gia de chimg minh %/a tang cuing phuang tier, cot sa ha ting va truyen thong xe vii xe duai sang hen an town ITS 2010 Oa NI* Bin An town xe nang cao sang kien, trong giai down 4, dang giai quyet xe, truyen th8ng xe bang each tray c#p vao mOt met he thong da nhiem (CSMA) dim tren phin ma ring eta ARIB STD T-75 Cruise - ha trq sang kit!' he thong duang cao t6c duqc xay dung tren he thong 5.8 GHz DSRC cling nhu he thong hi trq lei xe an town (DSSS) cling sir dung cOng nghe hang ngooi truyen thong cho xe ben 11 throng Cac hoot ding Smartway tap Ming vao cac djch vu ITS va mOt nen tang djch vu thong thuang duqc cung cip tren diu trang cat' cac mang hi& hien ca Trong thing 6 am 2007, n6 di duqc deg b6 kenh 10 MHz trong cac kenh tin s6 700 MHz se duqc phan b6 cho truyen thong lien quan den

an tan lien xe toi NI* Ban vim am 2012

CO mOt s6 do an deg nghiep chinh phi 6 MI duqc thrc hien vi duqc (Lang tren bao Hai trong s6 nhung do an de duqc m8 tit 6 duai day Lin diu tien Vehicle Infrastructure Integration (VII) duqc di ten thanh IntelliDrive, gin day met y tuang Ian dit duqc ch(rng minh Thir hai la do an ang dung truyen thong an town phuang tien

do kien se duqc kit thic vao cu6i am 2009 Ca hai du an tren duqc sv tai trq ctla 130

giao thong Hoa KI vi mOt s6 nha san xuit 8 to va nhi cung cep

Ngoii ra, hai do an khitc xirng clang duqc a Op ngin mOt chr an dang din

ra he thong an tan duqc tich hqp tren phuang lien lcham phi cac vim de giao dien ngutri-may vi mOt s6 img dung an town, vii khuyen cao ce khi Wing chang cheo hoc miu thuin, duqc xiy ra ding thai (Doi hoc giao thong vin di Michigan) Dv an tha hai li Cooperative Intersection Collision Avoidance Systemproject gam co ba thanh phin (McHale) Dv an canh bao vi phom 6 Michigan, do an Stop Sign Assist 6 Minnesota vi do an Signalized Left Turn Assist 6 California Kid xe duqc trang bj CICAS-V den gin mOt ngit tu, cac phuang tien nhon duqc tin hieu vi *Ong tin thai gian tit tin hieu den giao nhau (DSRC) MoSi chi& xe sau da se do down kha Wing ring n6 dang 6 NI tri c6 den do, vi neu thich hqp, cash bao trinh dieu Ichien (Maile) Dv an nay di duqc len Ice hooch dill nghiem vii trinh diet' khien don gian (Maile)

1.3.3 Kit qua can ak dr tin hifn tqi

a TYch kw co sd• hg ling (Vehicle Infrastructure Integration)

Trong ram 2005 130 giao thong van tai Hoa KI bit din di* nghiem met Meng mai Da s6 cac m8i twang that nghiem nay duqc thtrc hien 6 cac yang ngooi 8 phia tay bic cia Detroit, MI He thong bao gam 55 tram thiet bj trong yang 116.55km2 vi si

dung 27 chi& xe

C6 bay ung dung duqc phat Wen vi tha nghiem:

CIRIONG 1 Tong quan ve he thong mpg Vanet

—Bio hieu trong xe (In Vehicle Signage): RSE lien tic hien thj ra cac bin tin thong bio ben trong phucmg lien giao thong;

— Thu thop de lieu them do: Phuung tier di lei cung cap sir dft ligu ve vi tri

cua hciltieu bang vi chia se yeti RSE, me sau da n6 duqc bien soon vi phin tich;

— Thanh toin dies to - thu phi;

—Thanh totin dien to - bai d8 xe;

—Thong tin ngutri di chuyen/bang bit dinh huong;

—Thong tin dinh ki (Heartbeat): RSE thu thep thong bio tang this dinh kjr (vi

di nhu 100 msec) t r cac phuung tien bao gem ci tic dO xe vi vj tri;

—Hien thj tin hieu giao thong: quing be tang thid den giao thong

thuilouthies oetwaistroblyiniii

cgaintied4,einbang

&heath co p1ia talc

Hinh 1.3 Vi du he tang thik nghiem tgi Michigan (2008) MOt s6 kit qui quan tong dtrqc rut ra nhu sau:

— Ti le 18i gei tin la mot chic Wing mph me caa tom nhin thing Khi elm nhin thing dtrqc duy tri, ti le 18i g6i tin yin 6 mac thip them chi 6 khoing each 100m Khi tom nhin thing bj mit, ti le lai tang len nhanh chOng

— IPv6 yen hail tot

— Chi phi cho may thu GPS thip nhung dtrqc s* dung trong cac POC, !thong se cung cap cho phan lueng mac dO chinh xic

thanh cong

CHIrONG 1 T6ng quan ye h'e' &Ong mang Vanet

—Ung dung thong tin dinh Id lim viec tit cho phucmg tien trong khoing 100 m cua RSE (lily thuc vio tim quan sat thing)

— He thing an ninh da duqc hien thi de 1km viec, nhung chua chic chin Ngoii

To, kiem tra quy m6 chua duqc thuc hien

—Quin 1S, tai nguyen elk mpg truyin thong cho cac img dung chgy deg thbi phirc top hun du kien

—Cii dot, ciu hinh va duy tri RSE philc top hon va kh6 khan hon du kiln

Khi giai dogn nay mkt chuong trinh 7 khung kit thfic, BO ngo3i giao giao thong

v#n tai Hoa KS/ di thay vi tri vi di ten the chuong trinh 7 khung (Row) Ten mai cita no la IntelliDrive NO se nhin monh c8ng nghe khemg day trong cic dich vu ve i'mg dgng an Win Trich din "The Future of VII" (Row):

Chuong trinh maxi trong tuong lai tip hung nghien ciru cic hoot dOng trong nfring yang nhu sau:

—Cong nghe quit inh vi nhOn ding vi met s6 cac ceong nghe dem wing khac Nghien ciru, trinh chin, vi danh gia cac cong nghe cac ling dung an town da

—Nghien cuu tren cac lqi ich phu thuec t6i tinh di ding va m8i truemg

Buck diu, du an Safe Trip-21 dua ra nam 2008 vi di thanh 16p cac trang web Connected Traveler lam tra kit n6i et California Safe Trip-21 duqc thiet Ice de cai thien an town giao thong vi gikm iln tic bing cach xic dinh vi khai thic cong nghe hien co vi thich img cho cac nhu ciu giao thong v#n tai, vi g chimg minh ring nhing lien bO ding ke trong viec giai quyet yin de giao thong kheing co yen citu du to ca s6

hg ting lon (SafeTrip-21 nam 2008)

b ling dong trayin thong an tint

l'ing dung truyen thong an Willi xe (Vehicle Safety

Communications-Applications) (VSC-A) la du an gita nam nhi sin =it 8 to (Daimler/Mercedes-Benz, Ford, GM, Honda vi Toyota) vi BO giao thong v#n tii Hoa trong ba nam Day la

du in truyen thong diu lien de theo dii an totin cho xe (2002-2004), vi tip trong vio

CHUtiNG 1 TOng quan ve h4 thong mong Vanet

cic phuung tien truyen th8ng va dinh vi Wang dpi v6i muc tieu to dieu kien cho cac (mg dung an Wan tuang thich (Ahmed Zaid)

Do in VSC da xac dinh tam kich ban caa cic vu tai non "bang xep hung top composite", doa ten th6ng ke cua chinh ph6 Hoa Kp ve tin s6 vu tai non, chi phi, va cic khoan 16 trong cac nam hoot dOng Tren co s6 nay, VSC Qua ra bay Ong dung an town de giai quyet nhung tinh huing tai non Nhing Ong dung (Maile):

Cic phuang tien theo huOng

Dieu khien xe giam toc dO x x

Phuang tien khong la tic

Cac phuang tien thay d6i lan

LTAP/OD toi cac nut giao

Bang 1.1 Ban do mkt VSC-A img dung an toan va kich ban cac via tai nap, dtryc quan

tam nal

— Den bao phanh Ichin cip (Emergency Electronic Brake Lights) (EEBL): canh

&to ye xe phanh dOt ngOt 6 phia tru6c

— Canh bao dung dO phia tram (Forward Collision Warning) (FCW): earth bao

xe phia sau sip va chom vao xe phia tru6c

— Cinh bao diem mu (Blind Spot Warning) (BSW)/Canh bao chuyen lan (Lane Change Warning) (LCW): canh bao cho xe biet c6 xe lchac dang di clang huOng mu6n thay d6i lan duting ma nim trong diem mu Sau d6 khuyen cao cho dt ca cac xe nao dang n&m trong diem mu

CHUONG 1 Tang quan ve hg thing mpg Vanet

— H8 trq di chuyin qua giao 10 (Intersection Movement Assist) (IMA): canh bao khi d6 khong phiti la thtii diem an town de vao xa 10

—Canh btio khong vuqt qua (Do Not Pass Warning) (DNPW): canh bit° khi chiec xe sip va cham va yeu ciu they d6i lan dutmg neu c8 the

— Ciuth bao met kiem sofit (Control Loss Warning) (CLW): Ttr tito ra canh bao khi xe met kiem sat Cac xe Ichic se duqc doh bao phu thuOc vao moi de Oa

Trong filth vrc truyin thong, tip trong vao (Caminiti 2009):

— Thong di0p thanh

—Nang luqng tit* nghi0m

— Th8ng di0p ph6 Wen

— Hoot Ong da kenh

—Ph6i hqp va xac nhin tieu chuin

Nhi0m vu thong diep thanh phin di xtic djnh mOt thong di0p bao an total car ban trq tit ca cac ling dung an town (Caminiti) CEng vi0c nay anh hutmg manh me gin nhu hoan thank cac cuOc dam phan ve nh6m lam vi0c SAE J2735 Tieu chuin/ de nghj cuei cling duqc dua ra vao cuei nem 2009

CEng viec dul nghiem nang luqng kham phi Ong suit cao (> 20dBm) lam tang hi0u suit ling dung an tan, vi nang luqng thip (<20 dBm) chi ra dieu then tic nghen So sanh tS7 18i g6i (PER) xung quanh mOt "ngit to khip kin" 'thong c6 tim nhin thing, chr an di the hiOn duqc pham vi truyin thong hiOn tai hon giam 18i ding ke stI dung truyen tai dies nang 33 dBm (tren danh nghia 20 dBm) (Caminiti) Dieu nay cung cep mOt dating di thu vi cho khan' phi, dic bi0t IA trong nhttng thach thirc dot ra

boi cac thong tin truyen th8ng tim nhin thing duqc bao cao trong biva bao cao VIIC

(Kandarpa)

Cac ban tin ph6 tan se dieu tra vi0c sal dung c8ng suit, hic d), va dieu khien Ichfic de giam thieu sq tic nghen mpg va cal thien viec chuyen ban tin chi thien (Caminiti) Kit qua cuei cung di khong duqc tiet 10 tai thtri diem viet bai nay Tuy nhien, kit qui c6 ngay sau khi holm thanh du an VSC-A tong thing 11 nam 2009 VSC-A da tich cuc tham gia cac tieu chuin Ichac nhau DSRC, bao gtan IEEE 802.11p, IEEE 1609, va SAE J2735 (Caminiti)

Ngotli ra, VSC-A c6 mOt nhiim vu tip trong vao sq an town cita ban tin eta xe vai xe Tranh phtua cling bit° mit chuyen dung Dq an la &nit gia thuit than dubng cong elliptic chid 14 se (ECDSA) (Accredited Standards Committee), Ain d?ng ten thit tang the theo luttng thoi gian (Timed Efficient Stream Loss-Tolerant Authentication) (TESLA) (Perrig), va mOt phien ban situ di

CHUONG 1 TOng quan ve h'0 thin mpg Vanet

1.4 'CET LU*14

Trong chuang nay, tea di trinh bay lchai quit ljch sir hinh thAnh va phat trien mia VANET, nhung nguyen tic co ban vA thach thirc ctia mpg VANET

1.1-11) UM,' 2 t ruyen tnong tin trong mong v anet

CHUONG 2 TRUYEN THONG TIN THONG VANET

2.1 GIOI THIEU

Cac img dung an total VANET yeu ciu thong tin chi tir nhung vimg giai hon dja

1ST 6 gin xe day kh8ng phai la trueng hqp cho nhieu (mg dung ththin tien va ring dyng cho lai xe Vi du, he thing chi &Ong c6 the se dung thong tin trong mOt veng rung lan hcrn trong cac tinh huing giao thong hien toi MOt vi d i khic, he thing do xe eng dung VANET: nhttng thong tin phan loci ve tinh hlnh a xe trong toitn thanh phi Thong tin duqc thu th#p lien kit va chia se trong mOt yang rung Ion nhu mong luoi dueng cao tic hoc la mong lueri throng bei thanh phi Th8ng tin c6 the la m#t dO km lugng va theri gian di chuyen, cac nai a xe man phi va cac thong tin khac cif, the nhitng ngueri tham gia mpg khac theo dOi, va duqc thu th#p, phan logi beri cac thiet bj lien ket trong mpg Ad-Hoc tic dO cao

Phan loci thong tin trong VANET la mOt nhiem vu thach thec len N6 chi ce the lam duqc khi xem xet tAt ci cac tinh chit va glen hon cua cac thanh phin tong he thing mong VANET Dec biet c6 hai rang buOc lien quan la su ket n6i va sec chfra Qua trinh tham gia mpg bj gieri hon din den mOt mmig ter len thea.Ngay ca khi dot duqc tSI le tham Mt) cao, thi ket nii mong vin thueng xuyen bj hon che, vi du trong cac khoang then gian luu luqng thfp Trong cac hieu (mg khac tic de, ket n6i anh huong truc tiep den tic dO truyen tai thong tin qua VANET va do da truc lief) inh huong len su c#p nhop, su chia se thong tin

KM riling curt VANET con bj Nut chi bOi cac ket nii kh8ng day.Dung luqng mong se khong du de cung cip thong tin chi tiet vi lien tic cep nh#p mai thay d6i nh6

ye tinh hinh thrc the curt cac thinh vien trong mong.Dieu nay ding duqc nhin monh ben cac ket qua di duqc biet ten cac giOi hon cong mat c6a cac mpg !thong day da buerc Do khi Wing cua mong bj hon the doi hbi phai ce ca the de gam s6 ltnyng thong tin truyen qua mpg, bing cach teng hqp s6 lieu ci nhan

Khi Wing hon the cua VANET chri yen la do nhung hon chi cua cac kenh kheing day Bing truc giac to cung thiy r8 ring ring dung luqng cua mong se khong dii de cung cip thong tin chi tiet vi cip nh#t lien tic tren tit a cac th%rc the dja ly quy m8 nhe cho tat ci cac thinh vien cua mong KM nang the doi hoi phai c6 ca chi de giam si luqng thong tin can chuyen qua mong, bang cach tong hqp, tep hqp cac muc

de lieu ca !than

Bin thach thec chinh cua mong VANET:

— Lam the nio de c6 duqc thong tin, cu the la lam the nio de quan sit khu Arc

de hinh thanh mOt ca s6 delieu cho cac ting dung

Ltiu UNIT L iruyen tnong itn trong mpg v anet

—Lam the nao de vfm chuyin thong tin, tirc la cho ring thong tin co sin toi mOt

s6 diem trong mpg VANET vi lam the nao de cung dip cho cac ben quan tam trong cac phin khac cua mong

—Lam the nao de tom tit cac phep do cac thong s6 twang ttr hoc rat twang tv duqc thqc hien boi ngutri tham gia mpg VANET Ichac biet, de earn sir du thOa khi no kh8ng the quan sat het tit ca cac sir kien

— Lam the nao de thong tin t6ng hqp 16n horn cac thirc the (ha 1St, xem xet thuc to ring Icha nang han the cfia mong 'thong cho phep mOt cai nhit' chi tiet ve town

bO khu vqc rOng lon

MOt phac thao ca ban he thong ph6 hien duqc the hien tong hinh 2.1 ThOng tin duqc thu thOp tir cac ngu6n nOi b0 va ben ngorli (dm la, ter cac cam bien trong xe va c6

WI rang con ter ca se; ha tang ben duimg) vi duqc luu trif trong mOt ca so du lieu di biet NOi dung cita ca so dit lieu da Wet nay duqc dAng cho cac (mg dung, va chia se, trao d6i yen xe 8 to Ida& bang pinning tier truyen thong khong day SO hopg dit lieu trao d6i gitta cac xe duqc gialm bang citch ap dung 1E9 thu#t de tong ket va t#p hqp cac drr lieu trong ca sO drr lieu da biet

Trong phin nay se trinh bay bOn vim de dif neu 6 tren Phin tiep theo se xem xet cac yin de va de xuit, kieu dit lieu cuc b0, sau d6 xem xet cac vin de giao thirc truyen tai dit lieu toi muc 2.3 Sau de muc 2.4 va 2.5 bleu dien dit lieu va cac lchfa canh chuyin d6i, t6ng hqp, t#p hqp cac thong tin thu thftp duqc

Ifinh 2.1 Ong citing phd ban dira tren VANET

2.2 DO LikiNG VJ TRf HIgN HANH

Tnroc khi mOt Ong dung ph6 bien dva ten VANET co the bit du truyen thong tin, xir ljr da lieu, xac djnh vj to khu vtrc (t(rc la, do Wong cent mOt ho#c nhieu tham s6 b6) can phai duqc thqc hien Trong cite giao thirc ph6 bien dit lieu vi cac Ong dung dva tren cac cutoc that:, lu#n thuong dua ra cac thong s6 gia djnh ma bo qua cac

vivo Z iruyen tnong fin trong mang v anet

so lieu thuc 4 6 tren Tuy nhien, kung don gian de co the 'cac djnh vj tri cic bO, va sq lira chqn cac thong se duqc truyen trong mpg can duqc xem xet can th#n NO ply; thuOc rat nhieu vito muc dich cu the, muc dich ctla (mg dung, va no lien he met thiet vai cac thong s6 thiet ke !chic lien quan den ca cho, giao th(rc top hqp vv

2.2.1 Cam ban trong xe

Cac cam bien tich hqp trong xe se cung cap thong tin Nhieu bi) cam bien di cO sin va duqc sir dung cho cac he thong dien ter 'chic trong xe NO cung cap thong tin tren cac thong se mei trutmg nhu nhiet dO, cubing dO inh sang, vj tri (GPS), tec hoc dieu kien met du mg (bang, ntroc, vv) Cac thiet bj tinh vi vi xir ly logic Ong ce the cung clip thong tin nhu lchoing cach xe truck vi cac xe lien tiep (vi du, cite phep do khoing cach radar), tam nhin, hoc cac bien bio giao thong vi den giao thong (thong qua hinh anh camera vi nhtm clang hinh anh Icy thu#t)

Dqc ding to met ce the cung cap thong tin quan trqng va cho phep rut ra kit lu#n

ye tinh hinh giao thong hien tai Di cii thin tinh chinh xic vi chi tiet cilia cac thong tin, co the ket hqp thong tin tir nhieu nguan, qua trinh thutmg duqc gqi 11 cam bien nhiet hitch Ngay nay, nhieu cam bien xe da duqc kit noi thanh Controller - Area Network (CAN), theo quy djnh cua t6 chirc tieu chuan quik 4 (2003, 2004), vi viec dqc c6 the duqc chart Me thong qua kenh nay Kit he thong tich hqp vi kit hqp der

lieu dr cac nguan khic nhau de dat duqc cii nhin sau sac ye tinh tang throng hien tai

2.2.2 Clic he thong djnh vi nine la met ngmin thong tin

Phan lOn cic (mg dung tien lqi VANET cho din nay la it nhieu lien quan den mOt thong djnh vi Vi du la he thong phan phai thong tin cho viec tim kiem cic my& du6ng voi than gian ngan Ara tren tinh hinh giao thOng hien tai va mOt he thOng cho viec tim kiem nai da xe mien phi TO gOc nhin cOa he thOng thong tin trong VANET, thirc ti la ngiy rang nhieu phuang lien duqc trong bj he thong djnh vj, mOt h¢ than djnh vj kh8ng chi co thong tin chinh xic ve vj tri vi tOc di) hien tai, ma con dua ra thong tin ve huang xe du djnh den He thong dinh vi c6 the cung cap thong tin vi tri tren mOt mirc dO trUu tuqng cao han: thay vi tqa dO dja khi *it xe chuyin huong

hg thong cho biet ID duOng, huang lii xe, hoc them chi lan throng He thOng phin

phai thong tin giao thong nhu SOTIS mkt Wischhof H thong quan sat Wu hrqng boi Nadeem hoc CASCADE ciia Ibrahim va Weigle thuong sir dung vj tri xe va tac de, xe

la nguyen thay ca ban (sau de duqc trao dal trong hinh thin nhieu han hoc it km tong hqp) Neu muc dich cila (mg dung la t6i uu hda viec lira chon tuyen dutrng dim tren tinh hinh giao thong hien tai milt he thong duOng giao thong, mOt cach tap con khic la sir dung thin gian di chuyin doe theo down du6ng nhu cic quan sit cuc bO, voi

uivu 2 i ruyen tnong tin trong mang v anet

sv trq giep curt he thong djnh vj thi rat dan gian de c6 duqc cac thong se do tai dja phuang

2.3 TRUYEN TAI THONG TIN

Sau khi nh#n duqc thong tin to cac cam hien khic nhau, ne se tao ra met cai nhin t6ng quan ve tinh hinh quanh khu vvc de Tuy nhien, Icheng chi chi& xe c6 duqc thong tin nay mai can de lieu nay, ma con cac phuong den khic ding can thong tin nay de c6 the thich img vai nheng hanh vi cite ne Vi the, vies truyen thong tin cho nhitng chi& xe quan tam den thong tin de 11 rat quan tong Trong phim dub i se giii quyet van de ve truyin thong tin vai nheng phuang phap Ichic nhau De tranh nhi'mg quan niem sai lam thi phan nay se xac djnh cac dieu kien phat song, trap lit, va bao hieu nhu sau

Quang hi thong tin la cach duy nhat truyin met ban tin den tat ca cac nut trong phtun vi cua nut giri NO thueng duqc sir ding ham nguyen they de chung Iran lit, 6 day phuang phap su ding la phan phei mOt ban tin tren met pham vi Ong cua mpg khong day da buac Cac nut da nh#n duqc thong tin se quimg hi lei cac ban tin va do

de se cung cap cho tat ca cac nut trong mpg hoc mOt t#p hqp con cira chung, vi di cac nut trong met khu Arc dja ly giai hen Bao hieu them do la viec truyen tai thong tin djnh Icjr cho tit ca cac nut xung quanh Nh#n IA& bao hieu them do la viec quing ba djnh kjr Chi met gei duqc truyen boi bito hieu than' de duqc goi la mOt m6c bao

a Ctic giao fink truyin Mi titling tin

Phuang phap thin lit va truyin theo vi M dja ly cling duqc biet den la thuong xuyen duqc sir ding trong MANET, mOt trong nheng cach de truyen thong tin rat nhanh la sir ding trim lit Thv hien dan gifin la khi mo3i nut When duqc thong tin chi dan gian la se quang bi lai ne De trainh tang 'Op ban tin v8 hen, m8i nit se phat goi

tin met ltm.Ngoai ra, con dem thin gian sting (TEL) c6 the duqc sir dung de giOi

khu Arc, nth ban tin duqc phan phei Phuang phap tiep can nay se truyen mOt luqng

Ian cac gei de lieu du thea, co Ida Wing din den tic nghen nghiem tang Dieu nay

duqc goi la “vin de bao quang ba"

Trong mpg phuang tien, phuang phap train lvt thuong duqc sir citing de phe hien cac thong tin giao thong cho xe Ichic The tic chung la mOt chi& xe - nguan phat hien mOt sv kien hoc tinh hueng can thong bao cho cac xe khac Tir nguen nhu v$y thong tin bit dau thin ng.p Trong phan clued day giii quyet yeti nheng each tiep c(in Ichac nhau nhim mic dich han the sto luqng cac gei dtk lieu gi6ng nhau trong he thong 1r tdmg chung ciut tat ca cite phuang phap nay anh hutmg den hanh vi chuyin dip cea cac phuang tien, bang cach thich nghi vii thei gian khi chuyin tiep cac ban tin ho#c bang cacti dua ra cac quy dinh ye viec chi& xe c6 the chuyin tiep tit ca cac bin tin

Ltiu UNU 2 i ruyen tnong tin trong Inking v anet

De nh#n ra phtrang phap tran lut trong cac lin quang bat tuy thuec vao m#t dO giao thong Khi giao thong day d#c Ichong phai xe nit° ding can truyen lai thong diep Ngoai ra, quang bit thong tin ding co the dirge thich nghi von khoang catch giai han Trong vimg lan Om gin han thi ban tin duqc 10p di 1#p lai obi rit nhieu nut Bing catch ling nghe, 157 Wong nhit la tit ca hoc gin nhu tit ca cac nit gin v6i he thing quang

IA 0 duqc thong bio Vai khoang catch ngly cang tang thi tin s6 ctla quimg ba earn Hoc ce the sir dung tran lut b xung quanh nguOn mkt ban tin Dieu nay cho phep cac

xe b gin han ci the truyen thong tin nhanh nhit ma kh8ng phai bin lut ban tin nao vao

khu vrc rung han Trong Dombush vat Joshi nghien ciru dva vao ki thu#t "phat tan tin

din" (rumor spreading), "buen chuyen" (gossip), hoc "clich benh" (epidmice) day, met nut nIgin thong tin thi se luu lai ban tin hien thbi vat diy ne cho cac nit khac.Tuy nhien, nheng Icy thu#1 nay yen sir dung mOt catch dip c4 ► giting nhu trim Iv De hp chk s6 knyng tin nhin duqc truyen, cac nut sat quyet djnh chi phi bien cgc thong tin mai nhit Ngoai ra, co the co cac phucmg phap ket hap hai tiring nay De dap wing cac tieu chuin thich fin met de tY le chi c6 mOt vii xe se tiep tvc quimg bit cac thong tin mai duqc tao ra KM ban tin chuyen tiep lan len din den ttm si quang ba giam De tranh nheng vin de bao quang bit ci the km chi nhitng ban tin ding thtri

MOt de an khac de han the tran lit ctla dieing tin IA de cho ben nh#n quyet djnh

ci nen quang ba lai cac ban tin b tit ca cac nut Vi du trong Chisalita vat Shahmehri xem xet met catch tiep den nhu voy, mOc du chtl you nhin vao cac img dung an tan Gia djnh ring khi ghat hien tinh huing nguy hiem thi met ban tin canh bao se ducrc pang ba Ngtrqc lai chi don gian la quang ba lui ban tin nay, met be nh#n cac de lieu nay phan tich cho du no of) quan tam den citnh bao hay khong DO la trubng hap neu ben nhfm la lai xe tren cling mOt con &ding vat trong cling mOt huang von phuang tien nguin mkt ban tin Gilt djnh ring neu chinh ni quan tam den cac du lieu vat sau di cac

xe o to khac trong vung lan c#n ciut no cling c6 the huang lqi te ban tin Thong tin se duqc quang ba met lin nita Catch tiep con nay ci the duqc thea huemg cac thong tin b6 sung trong ban tin de de ding quyet djnh ma tren db cac nut duqc quan tam trong cac dl lieu Trong Ducourthial trinh bay mOt catch tiep On them dja chi dja ly vao ban tin de tao dieu kien thu#n lqi cho cac nit nh#n ci the phan tich Bing catch danh gib tinh tang sau di ci the quyet djnh xem ci nen chuyen tiep bitn tin Tong tlr nhu de

an Briesemeister de xuit ce tinh den khoang catch den met nut chuyen flip tnroc di Cang xa met nut thi kha nang quang ba lai cac ban tin nIgin duqc ngay can cao.Citc nut ling nghe truyen tai gift hai nut khong din quitng bit lei Sau khi truyen tai met yeu ciu quimg ba toi dt ca cac nut trong pham vi truyen tai gtri met cilia& gay nhieu duqc gqi la "bung no den" von thoi gian phu thuec vao khoang catch gitta nut gen vat cac nut nhan Nut xa nhit se girl chum gOi tin dal nhit vat chi ra bing cbch girl met

Ltiu ONIJ 2 1 ruyen thong Lm trong mpg v anet

"quang bi ro" c6 nglif la no muen nh#n duqc gii quing bi De earn cic chi phi ctla met qui trinh nhu vh, Zhao sir dung met cacti tiep can dlra tren djnh tuyen vi tri dia

15r day, nguai nh#n quyet dinh can cir vao met bang cic ving lin c#n chart cac nut ncri ma ban tin se duqc chuyen tiep Do viec sir dung "htrang din" trinh cluing bi, cic nut trong pham vi eua sing ling nghe ban tin

Trong nghien ciru ban du, Kosch de )(nit di me rung giao thirc djnh tuyen AODV cia Perkins vi Royer Uri met s6 chirc Hang truyen theo vi tri dja ljf Ban tin c6 chilli thong tin, vi du quang bi thong tin ye dieu kien dubng xi hien tai trong met khu vtrc nhit djnh Met phuang phip tiep can khic la thong tin duqc phi bien theo met tSr

le quan tam cue b6 Neu met nut nao nh#n duqc de lieu nay cuing se chuyen tiep ban

tin M#c di phuang phip nay hip din bbd ci the sir dung cic giao thirc hien co nhung

no lai ci han the la no co the duqc nhtm rung trong cac mpg Ian, nai rit nhieu nut la

nguin ciat thong tin De del phi vii cic miu luon di Ong khic biet cia mang phuang hen trong Sormani them met ca chi luu trEt vi chuyen tiep den cic nut tiep nh4n VI vbr, cac nut ding gip vao viec chuyen thong tin bing dutrng truyen kung day cling nhu bing each rieng curt no

Cin luu Sr ring trong khi truyen ban tin cic not quyet djnh c6 chuyin hip thong

tin dua tren lqi ich rieng ma khong quan tam den cac thong tin phi bien duqc cai thien Dieu nay di b#t ra duqc met vin de nghiem tong ye bleu suit

Williams va Camp so simh cic each tiep c#n tan lut khic nhau theo hieu suit va chi phi M#c dU nghien ciru nay duqc thuc hien trong bii canh chung dui mpg MANET, nhung kit qui c6 the rit httu ich cho VANET Ket qui vi ket lutut nhin manh ring cic phuang phip tiep cOn trim lut cho thiy hien suit tic nghen rit thip Trong mOt kjch ban phi) Wen thong tin phuang tien, thong tin tan lut ci the duqc bit diu Uri nhieu nut ding thai c6 the kit qui cis n6 lcheng hit nhu da trinh bay

b Yeti cliu fro lid

Truyen thong tin trong bei cinh khong ci giOi hart ye xe duce trang bj ling dung de chi phuang phip chit dung tiep can trin lut Neu nhieu ngueri sir dung gin nhung thong tin 'thong cin thiet thl co the la gii tri tic dung ter lai hoc do yeu can cult thuet twin Trong trulyng hqp nay, met chi& xe se yeu ciu met each r8 ring de c6 thong tin cu the bang each truyen met bin tin yeu ciu Diem den cuei cling cia gii tin nay c6 the duqc biet den, vi du neu ngteri ding yeu eau gii xing hien tai ciut cic he thing Ling flip theo hoc yeu eau so bai a xe cho met chi xe mien phi Khi Hang chuyin thong diep nay ci the duqc thuc hien theo nhemg each khic nhau

Cac ban tin yeu cau chuyen tiep trong truyen thong don hurong bang cach xay dung met tuyen r8 ring, hoc sir dung vi tri dua tren phuong phip djnh tuyen Cac ban tin

L.1-11JUINU Z i ruyen tnong un trong mpg v anet

frit lbi sau de a duqc tth lei tuang tu nhu yeu cau Thay vi yeu cau thong tin true tiep

t#i ngu6n, xe et-mg c6 the yeu cau cac xe khac di qua cung cap thong tin ma n6 biet ve

dieu db Thai gian chi dqi t#i den do c6 the keo dili du de dien de thong tin vio co so

drr lieu dA biet cua dja phuang bang each truy van chc xe lchic Trong hau het cac

nghien cuu khac yeu cau duqc thuc hien mOt each gian tiep bang cach cong b6 cac

muc ca sa dit lieu dja phuang MOt nut nhin duqc ban tin nay c6 the phan tich neu n6

biet thong tin de la men hockhang r6 ngtrbi yeu cau dim k5 thu#t khic nhau duqc de

xuat de thuc hien nhung ca the yeu cau Trong hinh 2 2 ma to mOt qua trinh c#p nh$t

dOc lip Ngoiti ra thu tic nay ding c6 the dua ra nhang kien th(rc cue b.) khi cac xe

khac c6 yeu cau r6 rang ve mOt nui cu the Ngtrqc lgi vai mOt ca the yeu cau tit 101

don huOng, mOt bulk gluing bi djnh lcSr yeu eau k9 thu#t clua tren mOt cau true clit lieu

tuang tu nhu mOt trong nhCmg nghien cuv dit de c#p a tren Han nits, bang ciich sir

dun kg thu#t de nein ch#n firth tiling qua tai ciut mang, de nghj dieu chinh tan s6 elk

than yeu cau tny thuOc vao mOt dO giao thong

Cosbddfludfbik

A 42,7

C 25,9

Cosadi/flu8ibik A42,7

B62,1

Hinh 2.2 Trao egi thong tin ngdm

(1) Hai chiec xe yeti hieu biet ca ban khac nhau

°NU 2 iruyen tnong tin trong mong v anet

(2) Xe ben trai truyen kien thirc rieng cfia minh Bing cach so sanh thong btio nay, chi& xe ben phai c6 the phan biet cac muc ma n6 dang so hthi va truyen cac thong tin an thiet cho xe ben trai

(3) Truyen tai cac muc thieu

(4) Xe ben trai da cop nh#t lden thirc cc; ban

De khic phuc cac phan veng VANET c6 the se dung cac phuong phap djnh tuyen cho phep tre tong the Kh8ng yeu cAu gel de lieu phai truyen theo met tuyin duong dinh them n6 c6 the truyen theo v1 tri dia ljr den met khu Arc nhit dish va c6 the duqc truyen di ngAm bing su di chuyin dui xe Bing cach nay, cac phan veng Ichac nhau c6 the duqc mb reng Viec chuyin cac ban tin tra lei theo cac quy tic tuang

tu nhu cac gel tin yeu ciu

Qua trinh yeu ciu/tra lbn phai 461 met voi vin de ma reng VANET c6 kha ming sir dung bit cir ngu6n nito hOi to ye vi kick thuOc cua mpg se tang len den ve cling

VI 4y, nhung phuong phap nay phai quan tam d#c biet a hp the viec trao 461 yeu ciu /tra Ibi cho cac phuang tien gin voi nhau hoc sir dtmg met s6 cach khac de him chi tai tren mgng

a Mom (Clustering)

Trong met s6 trutmg hqp ban tin trim lut vao tom be mpg la khong thich hqp va

se gay ra mirc dO tic nghen cao D6ng thoi yeu ciu/tra lbi c6 the kung thich hqp, vi

du thong tin se tre len can thiet neu c6 rit nhieu nut cling yeu au met Km Do de c6 cach Ichic de thay the cac gel de lieu trim lut, kung c6 ciu tnic cfia met s6 loci phan ph6i phan cip bang cach sir dung cum

Agarwal va Littletrinh bay mOt giao thirc Ian truyen c6 huong Directional Propagation Protocol (DPP) Phucmg phap nay xem xet ph6 bien cac thong tin tren cling &rang cao t6c Khi giao thong day d#c, met s6 nut trong khu vuc hinh thanh mOt nhom Trong nham nay thong diep duqc chia se voi tit ca cac net cfia nham nay

De truyen ban tin theo met huong, cum ch6ng click) duqc sir dung de truyen tai bin tin Cac cum theo huOng d61 10p duqc coi la truyen ban tin DPP thong qua the toc ctia mpg tre tong the Delay Tolerant Network (DTN) Neu Itheng c6 nhom chimg cheo viec truyen cac ban tin duqc thuc hien don gian bang cach se dung di chuyen cua xe

MOt cach tiep ph6 bien cling se dung cac thu#t phan nhom duqc de xuit bei Chang Neu met chi& xe can thong tin, ne With thanh met nhom Dieu nay bit diu qua trinh phan nhom De truyen de lieu vao cac nhom khac chuyen dip cac phucmg tien lc& not hai nhom Trong giai doon diu tien, thong tin trong met nhom duqc thu th#p trong Time Division Multiple Access (TDMA) Sau giai don tau tier, tat ca cac

utiu UNtJ L 1 ruyen tnong tin trong mang v anet

nhem dimg diu se cio tit ca thong tin ve cac xe trong nhOm ciut n6 Trong giai down thin hai thong tin sau d6 duqc girl ter lai cho nguiri diu tien, tiro la, cac nut yeu ciu MOt each dip c#n dua ten nhOm duqc trinh bay bid Chennikara Varghese.Xe trong mOt khu Arc 'the to tao thank met nhem Do vine ran On gin gui, ne c6 the true tiep giao tiep yid cac xe Tuy nhien, thong tin lien lac giea cac xe khk hok lit gifts cac nhem c6 the duqc thuc hien bang cac phucmg tien chuyen tiep la mOt phin cua

nhieu nhem Ta cfmg c6 the se dung phuang phap phan nh6m cac bai (18 xe tmh de ph6 bier trinh tang mkt bai xe

Leontiadis va Mascolo trinh bay phuang phip flap cOn dua tren me hinh di duqc xuit ban /clang ky Nhting bim tin duqc ph6 bien va duqc gift trong mOt khu vuc XaC

djnh truoc Neu mOt nut bit ld quan tam den tin nhin ce the Ming ky vao su !den nay tai dja phucmg Neu met ban tin duqc nhOn bOi nut ma ne ce the a clang kiem tra xem dieu nay phi hqp yin ding Icjf ciut minh hay khong Thong tin duqc nhan d8i va nhCmg bim sao nay duqc truyin den mOt s6 nut trong khu vtrc Neu met nut rid kit& thong tin khu Arc nay sau de duqc chuyen den mOt net di chuyen vao khu vuc hose vin con trong khu vuc Cac tac gia cho thiy trong nghien cim cua ho rang s6 Wong ban sao c6 the duqc tu dOng dieu chinh va not chung thip han so yid s6 luqng thus bao Sr khfic biet chinh cita phucmg phap nay so yid cac phuang phap ten la thong tin chin phai i lai trong mOt s6 khu Arc

Cach dip cOn duqc de xuit boi Shinkawa cimg chung mOt y tuemg Phuong tien

di lai c6 thong tin ye khu vuc hien tai dot no Neu n6 r0i kh6i khu vuc nay thi thong tin duqc b6 di Nhung de khong bj mit thong tin nay ten town khu Arc, dSe biet la neu mOt de da cac nit la thip, cac the giti de nghi su dyng deng chi' la "message ferries"

se khong quimg bit bit 14 thong tin Wien duqc

d Moe bdo (Beaconing)

Trong nhieu img dung VANET, de lieu thay dii theo thiri gian duqc mOi nut

ding b6 djnh k9 theo hInh thirc met m6c Bing each nay, tong tai mpg duqc gioi han den met mire de c6 djnh duqc xac djnh bid mot dO ctla cite nut va tin s6 m6c bao 1Chi nhan duqc quang bit met btok, cac nut kh8ng phim img lai bang each truyin din mid trip tiep Thay vim do ne tich hqp nOi dung ban tin vao ca sa de lieu di Wit ctia no Vii cac canh bao tiep theo d6 n6 se gei dieing tin nay, hoOc met phin biet sau d6 c6 the duqc phan ph6i dep

De toi da h6a vise ph6 bien thong tin yid cac hart the la xe chi ce mOt vii trang thiet bj va trong gay tic nghen trong mpg de thich nghi vii cac tSrle cita cac canh bao Vol khoang each ngity cling tang va toy thuec vao v#n t6c trong binh mkt xe doc theo met con duimg tin s6 ciut cac canh bito duqc truyen di la thich nghi Tuang tr

(Atli UNIT 2 i ruyen mong tin trong mpg v anet

nhu vOy Fujiki ding xuAt hien mOt ca the thich ling vol tS le canh bao dinh lcSr trong

khi db Wischhof khuyen nen dung thanh cac tai khoin cho du co nhang quan diem 'chic nhau ve tinh hinh giao thong a phat sinh tfr biut tin nh#n duqc Ngoai ra, Wu phan tich mei trubng cita mOt chi& xe Neu 0 mOt chi& xe mai Ian cdri xuat hien, mgt m6c duqc girl de c#p nh#t vao ca s6 dit lieu di biet dui nb

Saito sir dung mOt cach tiep TDMA nai mOt giay duqc chia than!) mu& khe.Khe cam duqc sir dung phu thuOc vao t6c a hien ttii dia mOt nut.Y tuOng la nett

cb ach tic giao thong Ric dO hiOn toi a bj giam va mOt canh bio duqc

Torrent-Moreno trinh bay mOt cach tiep On de idem soat tai trcing kenh duqc sir dung bbi cac canh bao an town va cung cap truyen den thong tin dang tin c#y hon cho ngubi nh#n \di ngubi girl Thay vi thay doi tin s6 cua cac canh bao nhu trong cac nghien cuu d8 de Op 6 tren chimg de xuAt dieu chinh khit nang truyen tai cita cac canh bao Muc dich lade giiun thieu nguy ca va chum gbi tin thong qua im tat va do de lam tang kha Wing nh n duqc citc canh bao

2.3.1 Cdi thin vic kit not mgng

Luu ter va chuyen tiep VANET kh8ng chi la mang thuimg xuyen thay dOi, ma

cbn la mOt mpg phan yang cao, ket n6i lien tuc 0 the kitting duqc gia dinh trong mOt thiet ke giao thirc De cho phep ph6 bien thong tin Lim xa voqt ra ngoai, plain mO Ong dia mOt plan yang mpg duy nhat, khai niem tilt cac mang tre tong the cb the duqc ap dung Dec biet, phuang phip tiep can kho luu trCt va chuyen tiep de vin chuyen thong tin la mOt nguyen tic xfty dung thong thuing ciia cac giao thirc pho bien VANET Trong mOt kho km trO va chuyen tiep cac nut cach tiep kh8ng thong bao ngay lop ttic ve phia truck, nhung mang cac thong tin cung vai nhang chuyen dOng Cult n6 Khi nhtIng ca hOi xuAt hien, vi du, bang each dap img cac xe khac, thong tin tiep tuc duqc truyen de chuyen tiep Trong trubng hop don gian, nb lay Ian rn6c bao khip nai

Khi nbi den viec thu hop khoang cach mpg gifts cac nhbm xe tren cling mOt con duing, quan sat thay ring viec sir dung cac xe dang di tai mang lai hieu xuAt cao hen Dec biet la khi thong tin ye dieu kien giao thong, throng giao thong duqc trao doi, nb

la quan tong de giao tiep clit lieu cho xe, lai xe 6 xa so voi khu vuc nai ma cac quan sat duqc thuc Men Thong tin ye tinh hinh giao thong nhu v#y tit cac nguOn tao ra thong tin chuyen Ong cung mOt huang la kheong huu ich Tuy nhien, sir dung giao thong dang tai a chuyen tiep cac thong tin rat cb the cai thien hieu suit cia he thing Dun vj ben throng

Hai cau hoi duqc at ra trong qua trinh truyen thong tin: tSr le tie= nhOp ttoi thieu thiet la gi, va cac yeu cau khic can phai duqc dap img a phO bien (earth bag)) ban tin nhanh hen ye su v#n Ong thuin tuy cua xe? T#p tning chinh 6 day la lieu nb cb the

CHUUNIal., truyen wrong tm trong mpg vanet

truyen dtt lieu mOt each nhanh cheng den cac Wag xa xed voi chi c6 mOt vii xe duqc

Dec 1(tp voi tt le than' nh#p ho#c met dO thief bj cu the, Yang vi Rettker quan sit ditc biet li trong viec trien khai, khi c6 rit it xe duqc trang bj, cac hien pbip dim boo

kit n6i b6 sung cho den mot dO cin thin cho nhieu erg dung sau nay disking xuyen duqc xic nhen H9 de nghi phis Lich tic dOng ctia cc( s6 ha tang bi• sung caz don vi ben le dubng Thiet bj ca s6 ha ding nhu 4y di xuit hien trong cic tai lien khic nhau

Vi du trong Goodman, cho thiy ngoii cic thong tin nhu gii sang c6 the dtVqc ctmg cip thong qua cic he thitng thong tin, hok chi dun gian b6i diem truy cep WiFi Cie dieu khoin khic di duqc so dung trong cic di lieu bao g6m (c6 dinh) cac "On vi h6 trq"

vi "don vi ben le Queue Roadside Unit (RSU) (3 dity, se so dung thu#t n thir hai RSU n6i chtmg ce the hi mOt tong hai thief bj dOc lip ma chi giao tiep v6i cac phuung lien thong qua truyin th8ng kheong dity, ho#c chimg c6 the thrqa kit n6i v6i

nhau thong qua mOt mpg xtrung song, tfr d6 c6 the duqc thqc hien hok bang c6 day

ho#c co se ha ting khOng day (GSM, UMTS, ), hok thong qua mOt along lir& call cite RSU Ve ca ban, muc dich ctja chkg 18 he lute kit not VANET cic ngu6n thong tin ben ngoii, hok de gia tang khi Wing kit not hoc khi Whig cda mpg Vi du

khi duqc lip d#t tai cOt den giao thong, cic thiet bj nay c6 the nhen duqc thong tin n1

xe 8 to di qua vi se thong bao cho cac xe mtfli duqc tiip cen yeti de lieu nay

1r Mang cda vier so dung logi co ar ha tang thief bit nay lchong phiti lit mei Tr?,

lai rim 1964, Bowes vi Covault trinh bay ket qui tb mOt thtl nghiem dtrqc so dung truyin thong phit thanh ben dubng H9 di phan tich cho du khi thi de cii ck RSU

a cung cep cic trinh dieu Bien them th8ng tin vi kiem soft giao them* Ben canh nheng thich that 1/ thuet cda he thong nhu very, ngteri so dung phai chip nh$n vi chi phi di duqc d(tt thanh yin de M#c dtl dieu kien lien quyet ky thuit la khli khic nhau, cac muc tieu ctia cac don vi ben throng di duqc so sixth yeti nhung thao lu$n nay nay Nhttng sq c6 khic nhau di duqc tit* nghiem di c6 mOt s6 filth huong ye an toan hooc hru luqng giao th8ng That bj v8 tuyin duqc cii d#t trong xe nh(tn duqc cic tin nhin

LkIU UNU 2 iruyat tnong trong mpg V anet

tfr cac cac don vj ben dating khi di ngang qua Tr& voi thong diep dft lieu ky thigh so stl dung ngity nay, ho sak dung tin nhin thogi diu ra thong qua loa phat tharth

Vi m#t thuyet ph& tich hieu suit (Art cic loci khic nhau tong c*c don vj ha thy D#c biet, xem xth cic kit nai RSU )(gang sting, ho#c cic he thong ea so, mpg luei RSU, va cec RSU doc 10p So sink s6 lugng 110 thiong clin thiet d4 gift cho sq ch#m g6i tin tap MOt kit lu#n la can nhieu han rat nhieu (5-7 lin) KW dimg mOt minh de dot duqc hieu suit Wang to nhu yid cac hu thing co so kit n6i yeti nhau Banerjee dung mOt m8 hinh tau tuqng, ngtiu nhien chuyin dOng nut 106i vol RSU dOc lip, nut di chuyen la quan tong di cung clip thong tin din cac Ang Mt hon Trong thqc to cac nut trong VANET thubng xuyen di chuyin theo mOt huemg (v1 du nhu, dal vol trung tam thanh ph6 trong gib cao diem bu6i sang) Nhu da di cup b ten, cic img dung then hinh ph6 ban th8ng tin tim xa_yeu ciu thong tin di theo Wang chuyin dOng chinh RSU kit noi yeti nhau c6 the dap Ong cac yew ciu nay vi phanh cheng cung cep thong tin den cac yang xa xed - hieu quit km nhieu so v6i cac R$U &mg mOt minh VI vily, trong thuc to VANET, lqi Ich hieu suit cua mpg RSU c6 the (Iv lden se thitt thOm chi con 16n horn

Cic RSU sear dung cling mOt Ong dung nhu cac phuang lien thong thding Di c6 mOt tic dOng ding ke, cite don vj ha trq duqc kit nal voi nhau thong qua mOt mpg xuang stag, chin hpn n6 c6 the sir dung mOt nen tang Id& thfrc chung: ngay sau khi

mOt dun vj nh#n duqc mOt s6 thong tin, tit ca cic cac dan vi ha trq khic c6 the stl dung ne vi dep tic phan ph6i Trong Locher, kiln Ira tic dOng ales s6 luting cac RSU yeu clu vi vi tri ctla n6 trong mOt thinh ph6 vac) thoi gian di hti tilt kiem dirt duqc vai mOt he thong dire tren thong tin giao thong VANET, va co the sit dung mOt sa thu#t Wan di truyin di tim kiem vi tri tat nhit cho cic RSU

IChai niem ve RSU Ithong bj gi6i han stir dung yeti cic chuong trinh Win mac

Vi du, phin tich lam the nio cac RSU dec lip hotic kit nai cung cap thong tin lien 1pc di ding horn gitta cic nhom xe Ttai day, ca ban cic diem iruy cep RSU thrqc d#t ben dubng, cang them gia trong giao thirc phan Whom

2.3.2 Truyin tdi tisOng tin

Trong khi thin Min lam the nio de vin chuyin th8ng tin trong mpg, nhieu nghien cfru citing xem xth truyen mOt phin cha thOng tin ho#c bin tin Mire dO pha hqp chirc Wing sir dung so skill drill moi ho#c tim quan trung c6a cac bin tin sin ch Co the stir dung tu6i vi khoang cach den mOt ngu6n tai nguyen cho cic chrrc Hang phi hqp, hotic phin lopi cac tin nhin nhin (taw theo teem quan trong cfia no KM truyen tii kiln thirc dja phuang din cic xe khic, mOt ban tin day la cho din khi Idich thu6c goi tin dot tai da Dieu nay se giap cic kich thy& ban tin 6 mOt mirc dO c6 ajnh vi tranh

11-1/UUNt-tl Inwen tnong tin trong mpg vanet

tic nghen mpg Citc s6 lieu khic de quyit djnh mOt phin th8ng tin dja pinning cin phai duqc truyin duqc de xuit t6t trong Saito cho catch tiep ckin khic nhau Trong mOt phuang phi!" lira chon xic suit Ichang ci sip the to cac thong tin (kw thqc hien nhung cac de lieu duqc gel duqc xdc djnh mOt cach holm town ngiu nhien Cling ci di nghj sip the to cac th8ng tin dua vio tu6i cult ni Trong trubng hqp ma chi sir dung cac th8ng tin mei nhit va phuang phip nay xem xet viec truyin th8ng tin ca di khemg lam mit th8ng tin

Trong Fujilci gift djnh ring th8ng tin v6 cac yang lan can Wit mOt chic xe duqc yeu ciu thubng xuyen hcm thong tin ve mOt khu Arc xa x6i VI thi, btu ich di truyin

tai cac de lieu thubng xuyen hon Adler di nghj tinh toga lqi ich town ciu (ctla mOt ban tin duqc gtlti Quyin lqi nay duqc s>Sr dung di them s6 quy trinh truy c(Ip trimg binh MOt ban tin thich hqp duqc diu tien, gig dotal r-Inh tranh &Tr sfra dpi theo thir ttir

uu tien clic ban tin Diiu nay duqc thuc hien bang catch thich nghi voi kith thy& cua eft s6 canh tranh Tuy nhien, trong mOt flied trilling c6 truyin di va xem )ott Oak suit) m8 hinh Ian truyin thuc ti hon dai phat thanh, nhung di la mOt phtrong phip uu tien c6 the se khong dal digit hieu qua mong mute

MOt catch dip cfn ngim ho#c tang thii mim di chia se thOng tin tong mOt Ichu vuc giii ban Gii dish ring niu hai chiic xe dap img, ni se trao thec dja phuang cua ni Di Ilan chi kich thuOc cua thong tin, chi c6 cac muc mai nhit duqc truyin di Mig 'chic, bing each them thong tin mai vio cac car so de lieu di hilt, de

lieu hien ci se c6 tu6i va mit sau mOt thoi gian

Ngoii viec c6 the di thong tin ban do vj tri cac thuc the hqp IS? trong mang lux% throng bO, cac th8ng s6 finh cila mpg lubi dubng bO duqc Wet din Uri a* he thing djnh vi (thing hen nhtr, tic dO d#c trong tree nhttng con dubng) cling c6 thi duqc sat thing rit len giup tao de lieu di la btu ich trong cac eng dung VANET 146 la mOt lua chon that ki di thong ha° cho cac xe khic chi trong Inking hqp lech gia trj "dien hinh" la ding ki Vi dy, mOt Ong dung thong tin giao thong ci the bio cat) thbi gian di chuyin chi khi ho c6 khic biet ding ki so vii nhttng gl thubng duqc du kiin tren con dubng tuong (mg Phuang phip tip ce ► nhu v(ty c6 kha Jiang c6 thi tiit kiem bang th8ng Di danh gig tai dja phuang cho dd tin tai dO Nth, thin gian di chuyin tuong Ong til cac de lieu ban doS tinh cila he thing dinh vj c6 the phuc vu nhu le mOt tai lieu them Ichio

Tuy nhien, c6 mOt vin di chung mkt cgc phuang phip tier, Qin “t6i truyin tai th8ng tin duy nhit tong nhttng hoin canh cu trong trubng hqp IchOng Co thong tin nil° algin duqc, n6 la khong tt rang cho tau nay bl do thuc ti ring tinh hinh la

"binh thubng", hotic xem lieu ci don gian la kh8ng ci pile') do hien tai, vi v$y kh8ng

l 1-11JUNly Z 1 ruyen thong un trong mvng vanet

ce gi duqc bat den MOt lin nea, toy thuOc vao cach thong tin duqc sb dung va gill thich bai cac (mg dung, dieu nay c6 the duqc chip nhin hay khang

2.4 TONG HOP CAC PREP DO

Cac phip do tyi die phtrung di duqc giai thieu de lam the nao co the thu duqc de

lieu va tim ra mOt s6 phuang phap de ce the truyin &Ong tin nay den tay nguei quan

tam Tuy nhien, viec phin phii tit ca cic phop do rieng le duqc thyc hi(in bai tit ca caz xe 6 t6 cho ben nhin nprai quan tam tree &rang, khu vyn la c6 the duqc ve ring it

thuyet vi tuang tuqng - nhung dieu nay hien nhien la dieu khang the VI the, co che yeu ciu giam so luting de lieu tong mang hong khi cac thong so mai toding duqc

theo del bei he thing khac, ma vi tri ctia xe va ciu tic wing luen luan thaw va de

lieu duqc trao d6i 6 bit dr nui nao ce the Do vty trong phin con lyi cia thuung nay

tip trung vao the vin de t6ng hqp, gong hqp so lieu do luting

Trong cac (mg dyng phi bien VANET, thubng lit train hqp c6 nhien phep do ten thng hoic tan cdc thyc the quan sat lien quan chit che ce s&n trong mpg Vi dy, nhieu xe c6 di qua cang down doting, m6i xe trong s6 di lyi do thin gifts di qua tha mink Neu ching duqc kit hqp thanh mOt gia tri duy nhit, vi khong cin that de ltru ter hai gia tri tyi et diem Quan trqng la sau d6 ding khang can thiet phai truyin hai gia tri lchi thong tin duqc trao don gifts nhttng nguai them gia myng Myc dich tha vier ket hqp lit de tao ra mOt de lieu duy nhit phan anh duqc thong tin Gqi la qua trinh kit hqp nhieu quan sat t6ng hqp

MOt hq hang ca tong hqp la tip hqp, va su khac biet gift tong hqp vi tip hqp khang phai lic nao cling re rang trong cac tai lieu (3 dily, tip hqp ce nglia la de lieu lien quan den nhttng thuc the khac nhau va duqc ket hqp thiinh mOt gia tri Myc Bich cia tip hqp la de two ra dyi dien de lieu kb& quit cdc khu vyn b khoing cich lan ham,

ce the tiet kiem bing th6ng thim chi con ket hqp cac phep do nhieu thane s6 twang tv

thong qua tong kit Trong phi n flip theo se de cip den tip kip

a 7157/s loin one mi awn bank

Hinh th(rc don gian nhit c6a t6ng hqp de lieu la khi mOt thiet bi them gia vao VANET thl phai dii nit vai hai gia tri rieng biet cho mOt them so (vi dy, $6 luqng ch8

418 xe mien phi tren mOt (Alt diem d8 cy the, hoic thbi gian cAn de di chuyttn thug mOt

down &rang): mOt trong cac gia tri c6 the duqc ltru tre tong co so de lien di cis ni,

gia tri khac duqc liy t>Y mOt ngu$n th8ng tin Vi dy, chi& xe c6 tuft di thuc quan sit cac tham so rieng va bay gilt nhin mOt gia tri twang ty UY mOt chi& xe khac Int nhttng th8ng tin them nhu nhin thai gian duqc luu tie vi duqc truyen cunt vOi de lieu thl ding khang phai la d8 clang chit de guy& dish co neu cep nhit gia tri hien tai trong

cu sa de lieu cin hay khang Xu vi Barth thao luin ve cac vin de gong hqp de lieu

LIIU UM.; Z iruyen thong un trong mong v anet

trong bii canh do thbi gian di chuyen doc doon doing Hq thiet lap khe thbi gian cfs dinh mubi phut, va ting kit cac phep do thin gian di loi ten cOng doon dubng thuOc_ cUng khe thbi gian Phuong thirc diu tien, khi thbi gian di loi doe theo mOt doon dubng

la nhen duqc tir mOt chiec xe Ichic, clic gia tri nhan duqc mkt dia phucmg &roc tinh

trong binh, va gia tri trong binh duqc hru Ire trong ca sO du lieu di biet Tuy nhien

phuang phip nay clang Wong hoot ding tit Vin di la cac pile') do duqc thyc hien som Ara° diu ctla mOt khe thbi gian thi gia tri Inmg binh ty gong &roc cep nhat Khi them cac pile') do duqc thyc hien sau nay, cac gia tri lirc diu di duqc cac xe khic biet

den, vi vay ma ho thubng nhan duqc cic thong tin men

b Nita do& gian dira tren so stink

Vin de nay chi ra Wong ye bi sung clic gia 14 do luting bang nhln thbi gian Khi mOt chiec xe bit diu quan sat, no luu trf klittng chi co gia tri quan sat thiy tong

ca sir de lieu coa no, ma don thbi gian hien hank Khi de lieu duqc chuyen den nhftng ngubi khic tham gia trio mong, cac nhan thbi gian duqc gui cOng vofri caa gia tit MOt

ca the "tang hop" dan gian ne thubng duqc sir dying trong cac tai lieu la de thay the

cho cac pile') do cu bang nheng phep do moi han, tren ca dr so sinh nhan thbi gian

Phucmg phip nhu trey gia dinh ring cac dam vi ding gap diy du chinh auk ding bO thbi gian Day lchtong phai la bit hqp 1Sr khi VANET cho phEp xe sir dung mOt s6 he thing nhu GPS b moi nai Cac he thing My c6 the ph►c vy nhu la Intl nguin thbi gian co dOi chinh xic cao, va do dO yeu ciu mist ding bO thbi gian la khong qui nghiem tong

Nhan thbi gian dya tren ca the so stinh chic chin tranh duqc yin de ma clic phep

do ce vin tin toi trong mong va thay vao de la ale iii tri moi hon dtroc thay the thubng xuyen Tuy nhien, no Ong ca nghTa ring gia tri trong co so du lieu cua mai chile xe se luon lute xuit phat tilr sy quan sat duy nhit Cho du day la mOt vin de hay

lchtong phi thuOc vim img dung, dac biet li no phy thuOc vao cdc nguOn ft lieu cu the:

tong he thing giing nhu mOt de milli caa Caliskan, ncri ca so ha tang cO ainh ( toi cdc

(ha diem d6 xe) too ra cac phep do gin nhu chfith xac, gia tri mai han se twc sy lute luon m8 to tinh hinh hien nay tot han so voi nhftng cai cri han Nhu tray, tong trubng hqp nay, thay the clic phep do ce dua tren nheng cai mei han la chic chin thick hqp,

va la mOt cach dl ding de dot duqc de lieu chit luting tit

Trong nhftng tinh hutong khic, dac biet la khi etc pig, do bi nhilu viec chi gift

loi mOt gia tri cep nhat mad nhit khong phai la mOt ttrang tit Khi thbi gian di chuyen thong qua quan sit troc tiep mla nhftng chi& xe, anh hiking den cac yeti t6 nhu cacti lai xe, cac tin bleu den co the gay ra cac hien dii lan Vi trey mil cac do Wong 'thong phin ail dung tinh hinh thyc te

Ltiuuriv 2 iruyen tnong tm trong mane v anet

c Moan thei gian dira fin link lode trims birth

Xu vi Barth dang tranh cii ye hai huang phit trien chuong trinh tinh toin trung binh thbi gian mil Ci hai thuit toin deu gin shin thbi gian cho gii thbi gian di chuyen Cich tiep diu lien la riga tren gin gii trf tali hon tong ltrog &tip hob tren trung binh: khi mOt quan sit man duqc thuc hien hoic khi gii tri nhin duqc tir chiec xe khic (khOng phan biet cho du diu thbi gian cult n611 man han hotic ion hen), tide toin tong luqng trung binh duqc thuc hien, gii trf ntlo ci hon thi se duqc gin tong s6 thip hon Vol cich tap centh ba, de nghf cop Whit thbi gian di chuyen dua Oen co so de lieu di biet chi khi tu chiec xe to ra mOt quan sit man han; xe 8 to khic tit nhien yin h6 trq trong viec phin ph6i cic gii trf trung binh Trong do, cic phuang time luu trQr s6

luong miu trong cic khe thbi gian hien tali cho den thbi diem hien tai, lcS7 hieu la n, T Whin thbi gian cis cic quan sit mai nhit dang gap vio gii trf, vi gii tri thbi gian di chuyen trung binh v bin than MOt o gii trf cia them s6 nay mad duqc quo sit thiy c6 the sau d6 trong xe quan sit duqc tich hqp trung binh trong mOt cich thick hqp, tao ra

tic v gii trf man, theo each sau:

v, =

n + 1(nv + a) (2.1) Khi mOt bin clip nhit duqc thuc hien, T duqc clip nhit den thbi diem hien tai, vi

n duqc tang len Cic thong si n vi T duqc trityin din cic xe khic cling vai gii trf trung binh hien tai Khi dft lieu duqc nhin cic phuang tien khic, dtra hien nhiin thbi gian T hoic gii tri cµc bO hoic gii trf nhin duqc se duqc ltru lei; gii trf ci hvn trong hai gii trf tren se bf

De in nay bio dim ring m6i ink chi duqc tinh mOt lin trong cic gii trf t6ng ket, with ca cite pile') do nay Op pan vio gii try' trung binh co cOng trong s6 N6 yin c6 the xiy ra, du, cic quan sit niy duqc thuc hien b6i mOt chic xe vi bao g6m gii tri bf mAt trong tic buac sau do Dieu niy xiy ra trong tinh huing sau My: gii set mOt chiec xe A thuc hien mOt quan sit vi dua vio trong ca sa dtt lieu di biet cia no Trong qui trinh hoot dOng, ne ding clip nhit nhin thbi gian lien quan Sau mOt thbi gian ngin, xe B ven chua nhen duqc de lieu cep nhet tb A, nhung n6 ttr thuc hien mOt quan sit cue thong s6 nay, vi doh hop no vio tong gii trf cqc bO tuang (mg Oa no DO lieu trong ca so dft lieu di biet cue B Wong c6 tic quan sit cilia A, nhung n6 mang mOt nhin thbi gian man ban Klu hai mqc de lieu nay duqc trao d6i trong mpg vi duqc so sinh, dtt lieu cia B se "thing" vi thay the citt lieu cue A, do d6 uu tien hold dOng cep nhit duqc thuc hien sam hen b6i A Vi 4y, deng gap cua A se bf mit Bit chip ket qui nay, Xu vi Barth tim ra ring trong ba de in ma ho de xtdit, phuang phip nay mang lai cic trinh bay chinh xic nhit cia cic gii tri thbi gian di chuyen chinh xic

d

ILINU 2 1 ruyen tnong un trong mpg v anet

MOt Win the lthic cia qui trinh fink toin tnmg binh duqc sir dung tong SOTIS

mkt Wischhof Cic ca chi chung ip dung cho tong hqp th8ng tin ttl nhieu ngu6n duqc

gqi li Segment-Oriented Data Abstraction and Dissemination (SODAD) SODAD lit

dine ten mOt phin cia doan dutmg Cic dap throng duqc ma hea cimg, do de tat ca cic xe d6ng nhit tr6n cling mOt phan doan, vi m& don c6 the dace gin mOt ID duy nhit Tai dja phucmg, cic phep do cia m8i xe duqc trao d8i gifta tic xe, do de mOt chi& xe nio de se c6 the thu th#p nhieu miu tiY vung lin c(In ngay liip tire De ph6 bier thong tin cho cic khu Arc xa hen tong ming, xe se kit hqp cic miu ma n6 c6

cho tic phin don dutmg lchic mi n6 dang di Khi tao, tic gii tri m8i (loan duqc gin

mOt nhin thlri gian th6i diem t6ng kit di duqc thuc hien.lChi n6 duqc ph6 bile tong

mpg, nhin th6i gian xic dinh gii tri hien tai tong co str de lieu ho#c mOt gii tq moi nh#n dirge luu gift

T6ng hqp SOTIS Doan during ID: 43 T6c d5 hung binh: 47.5

•

T6c 4:10 47 T6c tIO 52 Tic 50 48 Tic d0 43

Don (krona 43

Hinh 2.3 T4ng hqp toc d¢ cue xe tren miii phdn dogn trong SOWS

Ch6c ning quyet djnh cic min rieng to se duqc kit hqp nhu the nio vio mOt tong kit 6 m8i doan, li (mg dung phi) thuOc Trong throng hqp cu the curt SOTIS, the (mg dung dine ten trao d6i thong tin ve vin t6c cia xe Tham s6 do t6c xe hien tai Tem tit tic thong tin vin t6c mkt xe bang nhieu pile') do tren cling mOt phin down dutmg, gii tri trung binh duqc di:1h toin Bien de the hien trong hinh 2.3

2.5 TONG KIP DIY 'nu DIA Lit

Cic ky thu(tt duqc deg hqp thio luffn tong phin tnr6c cho phep so sinh vi kit hqp dftlieu tt nhieu lin quan sit lien quan din cling mOt thaw stS, gi6ng nhu t6c dO lii

xe hien hank ten cling mOt don &Ong trong SOTIS hoc s6 nui d6 xe ran phf ten cling mOt nai d xe trong hu6ng din d xe ccia he thOng cia Concklin Nhu v(ty, tong

kit c6 the gift s6 luqng dft lieu cua m6i lilting s6 duqc do kitOng that' dd He thong thrtrng lan hen of du nhu trong tan think ph6 ho#c mOt mpg luii du6ng cao t6c, tut'

vin con c6 mOt s6 luqng lan tic dft lieu bj mit: s6 linyng cac don Mow trong mOt thinh ph6, vi du, nhu li s6 bid d8 xe nhieu han Nei Chung, neu quan sit cic thong duqc dOng nhit vi dutc phan phiSi tren khu Arc cilia ming, sau de s6 krung ccla nto se