KHÓA LUẬN TỐT NGHIỆP HỒ TẤN HẢI đã chỉnh sửa

7/31/2019 KHA LUN TT NGHIP H TN HI chnh sa

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Tm hiu mt s giao thc nh tuyn trong mng cm bin khng dy

LI CM N

Vi tm lng tn s trng o v tri n su sc, em xin by t lng bit n n

thy Th.s Nguyn Gia Nh, ngi tn tnh hng dn, gp , ng vin em trong

sut qu trnh thc hin ti. Vi phng php lm vic khoa hc, kinh nghimthc tin, thy truyn t cho em nhng li khuyn qu bu lun vn nghip

ny hon thnh tt p.

Cm n tt c bn b, gia nh, nhng ngi lun ng h, ng vin,

khuyn khch v gip n hon thnh ng tin .

Cui cng em xin chn thnh bit n su sc n Ban gim hiu, Hi ng

qun tr cng qu thy c khoa Cng ngh thng tin trng i hc Duy Tn gip

em trong sut thi gian hc tp cng nh thc hin lun vn ny.

Xin chn thnh cm n!

nng ngy 10 thng 4 nm 2012

Sinh vin thc hin

H Tn Hi

H Tn Hi K14TMT


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DANH MC T VIT TT

AODVAd hoc On - Demand

Distance - Vector RoutingChui ch hng theo yu cu Ad hoc

ADV Advertise Bn tin qung bBS Bastation(Sink) Trm gcCH Cluster Head Node ch cm

CSMACarrier Sense Multiple

Accessa truy nhp cm bin sng mang

GAF Geographic Adaptive Fidelity Gii thut chnh xc theo a l

GEARGeographic and Energy-

Aware Routing

nh tuyn theo vng a l s dng

hiu qu nng lng

LEACH

Low Energy Adaptive

Clustering Hierarchy

Giao thc phn cp theo cm thch ng

nng lng thpMAC Medium Access Control iu khin truy nhp mi trngREQ Request Bn tin yu cu

PEGASISPower-Efficient Gathering in

Sensor Information Systems

Giao thc phn cp thu thp thng tin

trong h thng cm binSMP Sensor Management Protocol Giao thc qun l cm bin

SPINSensor Protocols or

Information via Negotiation

Giao thc nh tuyn thng tin qua s

tha thun

TDMA Time Division MultipleAccess

a truy nhp phn chia theo thi gian

VHDLVHSIC Hardware Description

Language

Ngn ng m t phn cng Mch tch

hp mt caoWLAN Wireless Local Area Network Mng ni ht v tuyn

WPANWireless Personal Area

NetworkMng vng c nhn v tuyn

WSN Wireless Sensor Network Mng cm bin khng dyMC LC

LI CM N ...............................................................................................................1

LI CAM OAN .......................................................................................................... 2

DANH MC T VIT TT ........................................................................................3

MC LC ..................................................................................................................... 3

DANH MC HNH V ................................................................................................6

M U ......................................................................................................................1

CHNG 1: TNG QUAN V MNG CM BIN KHNG DY ........................3

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Gii thiu v mng cm bin khng dy ...................................................................3

Cu trc mng WSN .................................................................................................4

1.2.1 Cu trc mt node mng WSN ....................................................................4

1.2.2 Cu trc mng cm bin khng dy .............................................................71.3 c im ca mng cm bin khng dy ............................................................8

1.3.1 Kch thc vt l nh ...................................................................................8

1.3.2 Hot ng ng thi vi tp trung cao ...................................................8

1.3.3 Kh nng lin kt vt l v phn cp iu khin hn ch ............................9

1.3.4 Tnh a dng trong thit k v s dng ........................................................9

1.3.5 Hot ng tin cy .........................................................................................9

1.4 Kin trc mng cm bin khng dy .................................................................10

1.4.1 Lp ng dng .............................................................................................11

1.4.2 Lp giao vn ............................................................................................... 12

1.4.3 Lp mng ...................................................................................................12

1.4.4 Lp lin kt s liu ..................................................................................... 13

1.4.5 Lp vt l ..................................................................................................13

1.5 K thut truyn dn khng dy .........................................................................14

1.5.1 Qu trnh truyn sng .................................................................................15

1.5.2 Cc cng ngh khng dy ..........................................................................17

1.5.2.1 Bluetooth .............................................................................................18

1.5.2.2 WLAN ................................................................................................. 19

1.5.2.3 ZigBee ................................................................................................. 20

1.6 Cc yu t nh hng n mng WSN .............................................................22

1.6.1 Thi gian sng bn ngoi ..........................................................................221.6.2 Tiu th ngun mc thp ...........................................................................23

1.6.3 Chi ph thp ................................................................................................23

1.6.4 Thng lng d liu ................................................................................... 24

1.6.5 Bo mt .....................................................................................................24

1.7 ng dng ca mng WSN ................................................................................25

CHNG 2:NH TUYN TRONG MNG CM BIN KHNG DY .............26

2.1 Gii thiu ........................................................................................................... 27

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2.2 s phn phi v tp hp d liu ........................................................................27

2.3 Thch thc trong vn nh tuyn ..................................................................28

2.3.1 Tnh ng ca mng ................................................................................... 28

2.3.2 S trin khai cc node ................................................................................292.3.3 Ti nguyn hn ch ....................................................................................29

2.4 Phn loi v so snh cc giao thc nh tuyn trong WSN ...............................30

2.5 Giao thc nh tuyn trong WSN ......................................................................31

2.5.1 Cc k thut nh tuyn .............................................................................. 33

2.5.1.1 Flooding v cc bin th ..................................................................... 33

2.5.1.2 Giao thc nh tuyn thng tin qua s tha thun .............................36

2.5.1.3 Truyn tin trc tip (Directed Diffusion) ...........................................40

2.5.1.4 LEACH (Low Energy Adaptive Clustering Hierarchy) ....................42

2.5.1.5 GAF(Geographic Adaptive Fidelity) ..................................................43

2.5.1.6 GEAR (Geographic and Energy Aware Routing) ...........................45

CHNG 3: SO SNH HAI GIAO THC NH TUYN PHN CP LEACH

V PEGASIS .............................................................................................................. 47

3.1 Kin trc giao thc LEACH .............................................................................. 47

3.1.1 La chn node ca cm ch .......................................................................49

3.1.2 Pha thit lp ................................................................................................ 50

3.1.3 Pha n nh ................................................................................................. 52

3.1.4 Giao thc ci tin LEACH C .................................................................55

3.2 Giao thc nh tuyn phn cp PEGASIS .........................................................56

3.2.1 Gii thiu PEGASIS ..................................................................................56

3.2.2 PEGASIS c bn ........................................................................................583.2.3 PEGASIS ci tin ......................................................................................59

3.2.4 nh gi u nhc im ca LEACH v PEGASIS .................................61

KT LUN ................................................................................................................. 62

TI LIU THAM KHO ........................................................................................... 63

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DANH MC HNH V

Hnh 1.1.Cc thnh phn ca mt node cm ng ..........................................................4

Hnh 1.2. M hnh trin khai c node cm bin khng dy ...........................................8

Hnh 1.3.Kin trc giao thc ca mng cm bin .......................................................10

Hnh 1.4.M hnh truyn sng ..................................................................................... 15

Hnh 1.5.Minh ha ng truyn sng .......................................................................16

Hnh 1.6. th so snh cc giao thc truyn dn khng dy ph bin ......................17

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Hnh 1.7.M hnh WLAN kt hp vi mng LAN truyn thng ................................19

Hnh 1.8.Bng tn IEEE 802.11b/g .............................................................................20

Hnh 1.9.M hnh giao thc ZigBee ............................................................................22

Hnh 2.1.Cc ng dng mng WSN ............................................................................27Hnh 2.2.Truyn d liu a chng ...............................................................................28

Hnh 2.3.Phn loi giao thc chn ng trong WSN ................................................30

Hnh 2.4.Fooding cc gi d liu trong mng thng tin ..............................................34

Hnh 2.5.Bng n lu lng do flooding ....................................................................35

Hnh 2.6.Vn chng ln do flooding .....................................................................35

Hnh 2.7.Hot ng c bn ca giao thc SPIN .........................................................37

Hnh 2.8.Th tc bt tay trong giao thc SPIN-PP .....................................................38

Hnh 2.9.Giao thc SPIN BC ..................................................................................39

Hnh 2.10.Hot ng c bn ca Directed Diffusion ..................................................42

Hnh 2.11.V d v li o trong GAF .......................................................................44

Hnh 2.12.S chuyn ng trng thi trong GAF .......................................................45

Hnh 2.13.Chuyn tip a l quy trong GEAR .....................................................47

Hnh 3.1.Giao thc LEACH ........................................................................................ 48

Hnh 3.2.Time line hot ng ca LEACH ..............................................................49

Hnh 3.3.Trng thi ca pha thit lp ..........................................................................50

Hnh 3.4.S hnh thnh cluster trong LEACH .......................................................52

Hnh 3.5.M hnh LEACH sau khi n nh trng thi ............................................53

Hnh 3.6.Hot ng ca pha n nh trong LEACH ...................................................54

Hnh 3.7.Time line hot ng ca LEACH trong mt vng ....................................54Hnh 3.8.S nh hng ca knh pht sng ................................................................54

Hnh 3.9.Pha thit lp ca LEACH C .....................................................................56

Hnh 3.10.Xy dng chui s dng thut ton Greedy ...............................................58

Hnh 3.11.X l li khi mt node trong chui cht .....................................................59

Hnh 3.12.Khc phc ca PEGASIS ...........................................................................61

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H Tn Hi K14TMT


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M U

L do chn ti

Trong qu trnh pht trin ca con ngi, nhng cuc cc mng v cng ngh

ng mt vai tr rt quan trng, chng lm thay i tng ngy tng gi cuc sngca con ngi, theo hng hin i hn. i i vi qu trnh pht trin ca con

ngi, nhng thay i do chnh tc ng ca con ngi trong t nhin, trong mi

trng sng cng ang din ra, tc ng tr li chng ta, nh nhim mi trng,

kh hu thay i, v.v... Dn s cng tng, nhu cu cng tng theo, cc dch v, cc

tin ch t cng c hnh thnh v pht trin theo. c bit l p dng cc cng

ngh ca cc ngnh in t, cng ngh thng tin v vin thng vo trong thc tin

cuc sng con ngi. Cng ngh cm bin khng dy c tch hp t cc k thut

in t, tin hc v vin thng tin tin vo trong mc ch nghin cu, gii tr, sn

xut, kinh doanh, v.v..., phm vi ny ngy cng c m rng, to ra cc ng

dng p ng cho cc nhu cu trn cc lnh vc khc nhau.

Hin nay, cng ngh cm bin khng dy cha c p dng mt cc rng ri

nc ta, do nhng iu kin v k thut, kinh t, nhu cu s dng. Song n vn ha

hn l mt ch n tiu biu cho cc nh nghin cu, cho nhng mc ch pht triny tim nng. p dng cng ngh ny vo thc t trong tng lai, c khng t

cc nh khoa hc tp trung nghin cu, nm bt nhng thay i trong cng ngh

ny.

Trong qu trnh tm hiu v nghin cu v mng cm bin khng dy, em

la chn tm hiu mt s giao thc nh tuyn lm hng nghin cu chnh. Cc giao

thc ny th hin thi gian sng, mc tiu th nng lng cng nh tc truyn

ca mng cm bin khng dy.Mc ch nghin cu

Lun vn ny em nghin cu mng cm bin khng dy. Mng cm bin

khng dy WSN l mng lin kt cc node vi nhau nh sng radio. Nhng trong ,

mi node mng bao gm y cc chc nng cm nhn, thu thp, x l v

truyn d liu. Cc node mng thng l cc thit b n gin, nh gn, gi thnh

thpl mt mng bao gm cc thit b di ng v tuyn kt ni ngang hng vi

nhau hnh thnh nn mt mng tm thi m khng cn s tr gip ca cc thit b

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trung tm cng nh cc c s h tng mng c nh, nn n va ng vai tr truyn

thng, va ng vai tr nh thit b nh tuyn. V vy cn nghin cu r cc giao

thc nh tuyn ngang hng, chn v tr v c bin l giao thc phn cp.

i tng v phm vi nghin cuNi dung chnh ca lun vn l i su nghin cu cc giao thc nh tuyn

nht l nh tuyn phn cp trong mng cm bin khng dy. ng thi nh gi, so

snh cc u nhc im ca giao thc nh tuyn phn cp trong mng cm bin.

Phng php nghin cu

Da vo l thuyt mng cm bin khng dy lm c s cho vic nghin cu

cc giao thc inh tuyn.

Da vo cc cng thc nh gi hiu nng cng nh nng lng trong hot

ng ca cc giao thc nh tuyn.

B cc lun vn

Lun vn gm 3 phn chnh

Chng 1: Tng quan v mng cm bin khng dy

Chng 2: nh tuyn trong mng cm bin khng dy

Chng 3: So snh hai giao thc nh tuyn phn cp LEACH vPEGASIS



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CHNG 1: TNG QUAN V MNG CM BIN KHNG DY

Gii thiu v mng cm bin khng dy

Mng cm bin (sensor network) l mt cu trc, l s kt hp kh nng cm

bin, x l thng tin v cc thnh phn lin lc to kh nng quan st, phn tch vphn ng li vi cc s kin v hin tng xy ra trong mi trng c th no .

Mi trng c th l th gii vt l , h thng sinh hc.

C 4 thnh phn to nn mt mng cm bin:

Cc cm bin c phn b theo m hnh tp trung hay phn b ri

Mng li lin kt gia cc cm bin( c dy hay v tuyn)

im trung tm tp trung d liu ( Clustering)

B phn x l d liu trung tm

Mng cm bin khng dy(Wireless Sensor Network) bao gm mt tp hp

cc thit b cm bin s dng cc lin kt khng dy (v tuyn, hng ngoi hoc

quang hc) phi hp thc hin cc nhim v cm bin phn tn v i tng mc

tiu. Mng ny c th lin kt trc tip vi node qun l ca gim st vin hay gin

tip thng qua mt im thu (Sink) v mi trng mng cng cng nh Internet hay

v tinh. Cc node cm bin khng dy c th c trin khai cho cc mc chchuyn dng nh gim st v an ninh; kim tra mi trng; to ra khng gian thng

minh; kho st, chnh xc ha trong nng nghip; y t;... Li th ch yu ca chng l

kh nng trin khai hu nh trong bt k loi hnh a l no k c cc mi trng

nguy him khng th s dng mng cm bin c dy truyn thng c.

Vic kt hp cc b cm bin thnh mng li ngy nay to ra nhiu kh

nng mi cho con ngi. Cc b vi cm bin vi b x l gn trong v cc thit b v

tuyn hon ton c th gn trong mt kch thc rt nh. Chng c th hot ng

trong mt mi trng dy c vi kh nng x l tc cao. Do , vi mng cm

bin khng dy ngy nay, ngi ta c th khm ph nhiu hin tng rt kh thy

trc y.

Ngy nay, cc mng cm bin khng dy c ng dng trong nhiu lnh vc

nh cc cu trc chng li a chn, nghin cu vi sinh vt bin, gim st vic chuyn

ch cc cht gy nhim, kim tra h sinh thi v mi trng sinh vt phc tp, v.v...



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Cu trc mng WSN

1.2.1 Cu trc mt node mng WSN

xy dng mt mng cm bin trc ht phi ch to v pht trin cc nt

cu thnh mng nt cm bin. Cc node ny phi tha mn mt s yu cu nht nhty theo ng dng: Chng phi c kch thc nh, gi thnh r, hot ng hiu qu

v nng lng, c cc thit b cm bin chnh xc c th cm nhn, thu thp cc

thng s mi trng, c kh nng tnh ton v c b nh lu d liu, v phi

c kh nng thu pht sng truyn thng vi cc node trong mng. Mi node cm

ng c cu thnh bi 4 thnh phn c bn, nh hnh 1.1, b cm nhn(sensing

unit), b x l(aprocessing unit), b thu pht (a transciever unit), v b ngun (a

power unit). Ngoi ra c th c th c thm nhng thnh phn khc ty thuc vo

tng ng dng nh l h thng nh v (location finding system), b pht ngun

(power generator) v b phn di ng (mobilizer).

Hnh 1.1.Cc thnh phn ca mt node cm ng

Cc b phn cm ng (sensing unit) bao gm cm bin v b chuyn i

tng t - s (ADC Analog to Digital Converter). Da trn nhng hin tng quan

st c, tn hiu tng t to ra bi sensor c chuyn sang tn hiu s bng b

ADC, sau a vo b x l.

B x l thng c kt hp vi b lu tr nh (storage unit), quyt nh

cc th tc cho cc node kt hp vi nhau thc hin nhim v nh sn.


B ngun B sinh nng lng

Sensor

Thit b x l

H thng tm v trThit b di ng

ADC Thit b nh

B cm bin B x l

B thu

pht


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Phn thu pht v tuyn kt ni vi cc node mng. Chng gi v nhn cc d

liu thu c t chnh n hoc cc node ln cn ti cc node khc hoc ti sink.

Phn quan trng nht ca mt node mng cm ng l b ngun. B ngun c th l

mt s loi pin. cc node c thi gian sng lu th b ngun rt quan trng, nphi c kh nng np in t mi trng nh l nng lng nh sng mt tri.

Hu ht cc k thut nh tuyn v cc nhim v cm ng ca mng u yu

cu c chnh xc cao v v tr, v vy cn phi c b nh v. Cc b phn di dng

i lc cn dch chuyn cc node cm ng khi cn thit thc hin cc nhim v

n nh nh cm bin theo di s chuyn ng ca con vt no .

Tt c nhng thnh phn ny cn phi ph hp vi kch c tng module.

Ngoi kch c ra cc node cm ng cn mt s rng buc nghim ngt khc, nh l

phi tiu th t nng lng, hot ng mt cao, c gi tnh thp, c th t lc

hot ng v thch ng vi mi trng.

Cc nghin cu gn y pht trin thng tin cng sut thp vi cc node x l

gi thnh thp v kh nng t phn b sp xp, la chn giao thc cho mng, gii

quyt bi ton quan trng nht ca mng WSN l kh nng cung cp nng lng cho

cc node b gii hn. Cc m hnh mng khng dy, c mch tiu th nng lng

thp c u tin pht trin. Hiu qu s dng cng sut ca WSN v tng quan

c da vo 3 tiu ch:

Chu k hot ng ngn

X l d liu ni b ti cc node gim chiu di d liu, thi gian

truyn

M hnh mng multihop lm gim chiu di ng truyn qua gim

suy hao tng cng, gim tng cng sut cho ng truyn

WSN c phn chia ra lm 2 loi, theo m hnh kt ni v nh tuyn m cc

node s dng.

Loi 1

S dung giao thc nh tuyn ng

Cc node tm ng i tt nht n ch

Vai tr ca cc node sensor ny vi cc node k tip nh l cc trmlp (repeater)



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Khong cch rt ln (hng ngn mt)

Kh nng x l d liu cc node k tip

Mng phc tp

Loi 2

M hnh a im im hay im im, mt kt ni radio n node

trung tm

S dng giao thc nh tuyn tnh

Mt node khng cung cp thng tin cho cc node khc

Khon cch ngn (v trm mt)

Node chuyn tip khng c kh nng x l d liu cho cc node kkhc

H thng n gin

Tiu chun tn s ang c p dng cho WSN l IEEE 802.15.4. Hot ng

ti tn s 2.4GHz trong cng nghip, khoa hc v y hc (ISM), cung cp ng

truyn vi tc ln n 250Kbps khong cch 30 n 200feet. Zigbee/IEEE

802.15.4 c thit k b sung cho cc cng ngh mng khng dy nh

Bluetooth, Wifi, Ultrawideband(UWB), mc ch phc v cho cc ng dng thng

mi.

Vi s ra i ca chun Zigbee/IEEE 802.15.4, cc h thng dn pht trin

theo hng tiu chun, cho php cc cm bin truyn thng tin qua knh truyn c

tiu chun ha

Nhiu nghin cu trong lnh vc mng mobile ad hoc(MANET). WSN tng

t nh MANET theo mt vi t im. C 2 u l chun mng wireless, multihop.Tuy nhin cc ng dng v k thut ca 2 h thng khng ging nhau.

Dn thng thng ca WSN l a ngun d liu truyn n ni nhn,

khc hn im im trong MANET.

Cc node trong WSN t di ng, nhng ad hoc l node di ng

Trong WSN, d liu t cc cm bin ch yu t cc hin tng, th

gii thc. Trong khi MANET ch yu l d liu



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Ngun gii hn nn nng lng ca WSN c qun l v s dng ht

sc cht ch. Trong MANET c th khng c s rng buc bi ngun

cung cp do cc thit b thng tin c th c thay th ngun cung cp

thng xuyn bi ngi dng. S lng node trong WSN ln hn gp nhiu ln trong MANET

=> Do s khc bit gia 2 m hnh giao thc m cc giao thc nh tuyn

trong MANET khng th p dng hon ton cho WSN. Tuy nhin WSN c th c

coi l mt phn trong MANET (ad hoc)

1.2.2 Cu trc mng cm bin khng dy

Giao tip khng dy multihop: Khi giao tip khng dy l k thut chnh th

giao tip trc tip gia hai node s c nhiu hn ch do khon cch hay cc vt cn.

c bit l khi cc node pht v node thu cch xa nhau th cn cng sut phi ln, v

vy chng ta cn cc node trung gian lm node chuyn tip gim cng sut tng

th. Do vy cc mng cm bin khng dy cn phi dng giao tip multihop.

T ng cu hnh: Mng cm bin khng dy cn phi cu hnh cc thng s

mt cch t ng. Cc node c th t xc nh v tr a l cu mnh thng qua cc

node khc (hay gi l t nh v)X l trong mng v tp trung d liu: Mt vi mng cm bin dng giao thc

x l ti node ngun trung tm, mt s giao thc x l theo cu trc hay gi l x l

d liu ti cc node. Thay v gi d liu n node chuyn tip, node s x l d liu

trc khi pht i. Vi dng c cu trc, d liu c x l ti mc tt nht nh

lm gim c bng thng v nng lng cn dng

Cc node cm bin c trin khai trong mt mi trng cm bin (sensor

field) nh hnh 1.2. Mi node cm bin c pht tn trong mng c kh nng thu

thp d liu v nh tuyn d liu v b thu nhn(sink) chuyn ti ngi dng

(user) v nh tuyn cc bn tin mang theo lnh hay yu cu t node Sink n cc

node cm bin. S liu c nh tuyn v pha b thu nhn (Sink) theo cu trc a

im khng c c s h tng nn tng (Multihop Infrastructureless Architecture), tc

l khng c cc tram thu pht gc hay cc trung tm iu khin. B thu nhn c th

lin lc trc tip ti trm iu hnh (task manager node) ca ngi dng hoc gin

tip thng qua Internet hay v tinh.



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Hnh 1.2.M hnh trin khai c node cm bin khng dy

1.3 c im ca mng cm bin khng dy

1.3.1 Kch thc vt l nh

Trong bt k hng pht trin cng ngh no, kch thc v cng sut tiu th

lun chi phi kh nng x l, lu tr v tng tc ca cc thit b c s. Vic thit k

cc phn cng cho mng cm bin phi ch trng n gim kch c v cng sut tiu

th vi yu cu nht nh v kh nng hot ng. Vic s dng phn mm phi to ra

cc hiu qu b li cc hn ch ca phn cng.1.3.2 Hot ng ng thi vi tp trung cao

Phng thc hot ng chnh ca cc thit b trong mng cm bin l cm

bin v vn chuyn cc dng thng tin vi khi lng x l thp, gm cc hot ng

nhn mt lnh, dng, phn tch v p ng li. V d, thng tin cm bin c th c

thu nhn ng thi bi cc cm bin, c thao tc v truyn ln mng. Hoc d liu

c th c node cm bin nhn t cc node cm bin khc v c hng ti nh

tuyn a lin kt hay lin kt cu. V dung lng b nh trong nh nn vic m mt

khi lng ln d liu gia dng vo v dng ra l khng kh thi. Hn na, mi

dng li to ra mt s lng ln cc s kin mc thp xen vo hot ng x l mc

cao. Mt s hot ng x l mc cao s ko di trn nhiu s kin thi gian thc. Do

, cc node mng phi thc hin nhiu cng vic ng thi v cn phi c s tp

trung x l cao .



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1.3.3 Kh nng lin kt vt l v phn cp iu khin hn ch

S lng cc b iu khin c lp, cc kh nng ca b iu khin, s tinh vi

ca lin kt x l - lu tr - chuyn mch trong mng cm bin thp hn nhiu trong

cc h thng thng thng. in hnh, b cm hay b truyn ng (actuator) cungcp mt giao din n gin trc tip ti mt b vi iu khin chip n. Ngc li,

cc h thng thng thng, vi cc hot ng x l phn tn, ng thi kt hp vi

mt lot cc thit b trn nhiu mc iu khin c lin h bi mt cu trc bus

phc tp. Cc hn ch v kch thc v cng sut, kh nng nh hnh vt l trn vi

mch b gii hn c chiu hng cn h tr qun l dng ng thi, tp trung nh b

x l kt hp

1.3.4 Tnh a dng trong thit k v s dng

Cc thit b cm bin c ni mng c khuynh hng dnh ring cho ng

dng c th, tc l mi loi phn cng ch h tr ring cho ng dng ca n. V c

mt phm vi ng dng cm bin rt rng nn cng c th c rt nhiu kiu thit b

vt l khc nhau. Vi mi thit b ring, iu quan trng l phi d dng tp hp cc

thnh phn phn mm c c ng dng t cc thnh phn phn cng. Nh vy,

cc loi thit b ny cn mt s iu chnh phn mm mt mc no c

c hiu qu s dng phn cng cao. Mi trng pht trin chung l cn thit

cho php cc ng dng ring c th xy dng trn mt tp cc thit b m khng cn

giao din phc tp. Ngoi ra, cng c th chuyn i gia phm vi phn cng vi

phn mm trong kh nng cng ngh.

1.3.5 Hot ng tin cy

Cc thit b c s lng ln, c trin khai trong phm vi rng vi mt ng

dng c th. Vic p dng cc k thut m ha sa li truyn thng nhm tng tincy ca cc n v ring l b gii hn bi kch thc v cng sut. Vic tng tin

cy ca cc thit b l l iu ct yu. Thm vo , chng ta c th tng tin cy

ca ng dng bng kh nng chp nhn v khc phc c s hng hc ca thit b

n l. Nh vy, h thng hot ng trn tng node n khng nhng mnh m m

cn d dng pht trin cc ng dng phn tn tin cy.



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1.4 Kin trc mng cm bin khng dy

Trong mng cm ng, d liu sau khi c thu thp bi cc nt s c nh

tuyn gi n sink. Sink s gi d liu ngi dng u cui thng qua internet

hay v tinh. Kin trc giao thc c s dng bi node gc v cc node cm binKin trc giao thc ny kt hp gia cng sut v chn ng, kt hp s liu

cc giao thc mng, s dng cng sut hiu qu vi mi trng v tuyn v s tng

tc gia cc node cm bin. Kin trc giao thc bao gm lp vt l, lp lin kt d

liu, lp mng, lp giao vn, lp ng dng, phn qun l cng sut, phn qun l di

ng v phn qun l nhim v.

Hnh 1.3.Kin trc giao thc ca mng cm bin

Tu theo nhim v cm bin, cc kiu phn mm ng dng c th c xy

dng v s dng trn lp ng dng. Lp giao vn gip duy tr dng s liu khi cc

ng dng ca mng cm bin yu cu. Lp mng tp trung vo vic nh tuyn sliu c cung cp bi lp giao vn. Do mi trng c nhiu v cc node cm bin

c th di ng c, giao thc MAC phi c tnh ton v nng lng v ti thiu

ha va chm trong vic pht qung b vi cc node ln cn. Lp vt l s dng cc

k thut iu ch, truyn v nhn cn thit n gin nhng mnh m. Thm vo ,

cc mt bng qun l nng lng, di ng v nhim v iu khin s phn phi nng

lng, phi hp di chuyn v nhim v gia cc node cm bin. Cc mt bng ny



19/71


gip cho cc node cm bin c th phi hp trong nhim v cm bin v gim c

tng nng lng tiu th.

Mt bng qun l nng lng qun l vic mt node cm bin s dng nng

lng ca n nh th no. V d, node cm bin c th tt b phn nhn sau khi nhnmt bn tin t mt trong cc node ln cn. iu ny c th trnh c vic nhn bn

tin ti hai ln. Ngoi ra, khi mc nng lng ca node cm bin thp, node cm bin

s thng bo ti tt c cc node ln cn rng mc nng lng thp ca n thp nn

n khng th tham gia vo vic nh tuyn cho cc bn tin. Nng lng cn li c

d tr cho vic cm bin. Mt bng qun l di ng d tm v ghi li chuyn ng

ca node cm bin, v th mt tuyn ng hng ti node user lun c duy tr v

cc node cm bin c th theo di c cc node cm bin ln cn. Vi vic nhn

bit c cc node cm bin ln cn, node cm bin c th cn bng gia nhim v

v nng lng s dng. Mt bng qun l nhim v cn bng v sp xp nhim v

cm bin cho mt vng c th. Khng phi tt c cc cm bin trong vng c

yu cu thc nhim v cm nhn ti cng mt thi im. Kt qu l mt vi node

cm bin thc hin nhim v nhiu hn cc node khc tu theo mc nng lng ca

chng. Nhng mt qun l ny rt cn thit, nh vy, cc node cm bin c th lm

vic cng vi nhau c hiu qu v mt nng lng, c th nh tuyn s liu trong

mt mng cm bin di ng v chia s ti nguyn gia cc node cm bin. Nu

khng, mi node cm bin s ch lm vic mt cch n l. Xut pht quan im xem

xt trong ton mng cm bin, s hiu qu hn nu cc node cm bin c th hot

ng hp tc vi nhau, nh th cng c th ko di tui th ca mng.

1.4.1 Lp ng dng

Mc d nhiu lnh vc ng dng cho mng cm bin c vch r v c xut, cc giao thc lp ng dng cn tim tng cho mng cm bin vn cn l mt

vng rng ln cha c khm ph. Trong lp ng dng c ba giao thc quan trng

l giao thc qun l cm bin SMP (Sensor Management Protocol), giao thc phn

nhim v v qung co s liu TADAP (Task Assignment and Data Advertisement

Protocol), giao thc truy vn cm bin v ph bin s liu SQDDP (Sensor Query

and Data Dissemination Protocol), rt cn thit cho mng cm bin trn c s nhng

s c xut c lin quan ti nhng lp khc v cc lnh vc ng dng mng



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cm bin. Tt c cc giao thc lp ng dng ny u l nhng vn nghin cu c

tnh m.

1.4.2 Lp giao vn

Lp giao vn cung cp cc dch v t chc lin lc u cui t cc node cmbin c bo co cn chuyn ti node thu nhn (Sink) v node ngi s dng. Lp

giao vn c bit cn thit khi h thng c k hoch truy nhp thng qua Internet

hoc nhng mng bn ngoi khc. Giao thc TCP vi c ch ca s truyn dn cha

ph hp vi c trng ca mi trng mng cm bin hin nay. Do , vic thit lp

mt lin kt u cui t cc node cm bin trc tip n node qun l ca ngi s

dng l khng hiu qu. Phng php phn tch TCP l cn thit mng cm bin

tng tc vi cc mng khc v d nh Internet. Trong phng php ny, kt ni

TCP c s dng lin lc gia node qun l ca ngi s dng v node thu nhn

(Sink) v mt giao thc lp giao vn ph hp vi mi trng mng cm bin c s

dng cho truyn thng gia node thu nhn v cc node cm bin. Kt qu l truyn

thng gia node ngi s dng v node thu nhn c th s dng giao UDP hoc TCP

thng qua Internet hoc qua v tinh. Mt khc, vic truyn thng gia node thu nhn

v cc node cm bin ch s dng hon ton cc giao thc kiu nh UDP, bi v cc

node cm bin c b nh hn ch.

Khng ging cc giao thc kiu nh TCP, cc phng php truyn thng u

cui (end to end) trong mng cm bin khng a ch ton cc. Cc phng php ny

da trn vic t tn thuc tnh c s ch ra im ch ca gi s liu. Cc nhn t

nh tiu th nng lng, kh nng m rng v cc c trng nh nh tuyn tp

trung s liu khin cho mng cm bin cn phi c nhng c ch khc trong lp giao

vn. Yu cu ny nhn mnh s cn thit ca nhng loi giao thc mi lp giaovn.

1.4.3 Lp mng

Vic nh tuyn trong mng cm bin phi i mt vi rt nhiu thch thc

nh mt cc node dy c, hn ch v nng lng Do vy thit k lp mng

trong mng cm bin phi tun th cc nguyn tc sau:

Hiu qu v nng lng lun c xem l vn quan trng hng u

Cc mng cm bin gn nh l tp trung d liu



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Vic tp hp d liu ch c thc thi khi n khng cn tr hot ng

hp tc ca cc node cm bin

Phi c c ch i ch theo thuc tnh c bit v v tr

C rt nhiu giao thc nh tuyn c thit k cho mng cm bin khngdy. Nhn tng quan, chng c chia thnh ba loi da trn cu trc mng, l

nh tuyn ngang hng, nh tuyn phn cp, nh tuyn da tho v tr. Xt theo hot

ng th chng c chia thnh nh tuyn da trn a ng (multipath-based), nh

tuyn theo ng truy vn (query-based), nh tuyn tha thun (negotiation-based),

nh tuyn theo cht lng dch v (Qos-Quanlity of Service), nh tuyn kt hp

(coherent-based). Chng ta s tm hiu k cc giao thc nh tuyn chng sau.

1.4.4 Lp lin kt s liu

Lp kt ni s liu chu trch nhim cho vic ghp cc lung d liu, d

khung d liu, iu khin truy nhn v sa li mi trng. V mi trng c tp m

v cc node cm bin c th di ng, giao thc iu khin truy nhp mi trng

(MAC Media Access Control) phi xt n vn cng sut v phi c kh nng

ti thiu ha vic va chm vi thng tin qung b ca cc node ln cn.

1.4.5 Lp vt lLp vt l chu trch nhim la chn tn s, to tn s mang, tch sng, iu

ch v m ho s liu. K hoch chn tn s c trnh by trong bng 1.2. Vic

to tn s v tch sng thuc phm vi thit k phn cng v b thu pht nn s khng

c xem xt y. Cc phn tip theo s ch trng v cc hiu ng pht sng, hiu

sut nng lng v cc phng php iu ch trong mng cm bin.

Hin nhin l truyn thng v tuyn vi khong cch xa l rt tn km xt c

v nng lng v phc tp ca hot ng. Trong khi thit k lp vt l cho mng

cm bin, vic ti thiu ho nng lng c coi l rt quan trng, ngoi ra cn cc

vn v suy hao, pht tn, vt cn, phn x, nhiu, cc hiu ng fading a ng.

Thng thng, cng sut u ra ti thiu chuyn mt tn hiu qua mt khong

cch d t l vi dn , trong 2 n < 4. S m n gn 4 vi antenna tm thp v cc

knh gn mt t in hnh trong mng cm bin. Nguyn nhn l do s trit tiu mt

phn tn hiu bi tia phn x mt t. gii quyt vn ny, ngi thit k phi

hiu r cc c tnh a dng c hu v khai thc chng mt cch trit . V d,



22/71


truyn thng qua nhiu bc nhy trong mng cm bin c th vt qua mt cch

hiu qu cc vt chn v cc hiu ng suy hao ng truyn nu mt node mng

ln. Tng t, trong khi suy hao ng truyn v dung lng knh hn ch tin

cy ca s liu th nh ta c th s dng li tn s theo khng gian.

Bng 1.1 Cc di tng dnh cho cc ng dng Cng nghip, khoa hc v y t ISM

Vic la chn phng thc iu ch tt l vn quyt nh i vi s tin

cy trong truyn thng ca mng cm bin. Trong khi mt phng php iu ch c

s M c th gim c th gim thi gian truyn dn bng vic gi nhiu bit trn mt k

hiu th n li lm tng phc tp ca mch in v tng cng sut v tuyn. Vi

iu kin cng sut khi kch vt tri th phng php iu ch c s hai c hiu

qu v nng lng hn. V th, phng php iu ch c s M ch c li vi cc h

thng c cng sut khi kch thp.

1.5 K thut truyn dn khng dy

Mng WSN c th s dng mt s cng ngh truyn dn khng dy c thit

k sn (Wireless COTS) nh l Blutooth/Personal Area Networks (PAN), ZigBee,

Wireless Lan (WLAN), hostspots, broadband Wireless acecss (BWA)/ Wimax, v 3G


Di tn (kHz) Tn s trung tm (kHz)

6765 - 6795 6780

12.553 - 13.567 14

26.957 - 27.283 27

40.66 - 40.70 40.68

433.05 - 434.79 433.92

902 - 928 915

2400 - 2500 2450

5725 - 5875 5800

24 - 24.25 24

61 - 61.5 61.25

122 - 123 122.5

244 - 246 245


23/71


1.5.1 Qu trnh truyn sng

Truyn sng radio dng trong mng WSN thng di dng trc tip hay

khng gian t do. Sng pht ra t ngun, i theo tt c cc hng theo ng thng,

nng lng thay i theo t l nghch vi khong cch , suy hao mi trng khngphi l khng gian t do (nh cp ng trc, vt liu xy dng, ta nh, vt cn) .

Hnh 1.4.M hnh truyn sng

C th chia lm 3 thng s nh hng n qua trnh truyn sng:

Phn x (Reflection): sng c bc sng ln so snh c vi vy

th, b mt nhn. S phn x xy ra t b mt tri t, ta nh hay

tng

Nhiu x(Diffaction): ng truyn radio t my pht n my thu b

cn tr bi b mt vt th c nhiu nh, gc nhn.

S phn b rng ri (Scattering): cc vt th c kch thc nh hn

bc sng nm trn ng truyn sng. Cc b mt nhm, g gh, nh

c th gy ra hin tng ny.

Nhng hin tng ny dy ra s mo dng v gim cng sut tn hiu. S dao

ng nng lng tn hiu gy ra do tn hiu thu c l s kt hp sng phn x t

cc hng khc nhau v cc thnh phn nhiu x, phn b ri vi tn hiu hng trc

tip. Gi l nhiu a ng (multipath). iu ny nh hng n c my thu di ng



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ln c nh, my thu t trong nh hay ngoi tri. S suy hao do c tnh sng in t

suy hoa theo khong cch gi l large-scale, s suy gim do s di chuyn my thu,

phn x, tn sc hay phn b ri gi l small-scale.

c tnh knh truyn thay i theo khng gian v thi gian. Tt c cc hintng ni trn nh hng kh ln n cng sut my thu nhn c, d l thit b c

nh, tn hiu thu c vn c th b suy gim bi v s di chuyn ca cc vt th

xung quanh

Dng vt liu Tn s Suy hao truyn dn (dB)

G800 MHz

5 6 GHz

4 7

9 18

Gch 4 6 GHz 14

B tng2,4 GHz

5 GHz

5

5 10

voi, thch cao2,4 GHz

5 GHz

3

5

Sn bng g 5 GHz 9

Sn bng b tng 900 GHz 13Bng 1.2 Trch dn mt s suy hao ng truyn do vt liu lm theo tn s

Hnh 1.5.Minh ha ng truyn sng

My thu nhn c nhiu tn hiu cng lc tn hiu gc v phn x, tn

sc(nh hnh 1.5), do c th khng phn bit c tn hiu cn thu. Tuy nhin, di

anten my pht hoc my thu khi v tr hin ti mt vi mt c th ci thin ng k



25/71


cht lng tn hiu. Vn a ng trong cao tn c th bt nh hng bng cch

nng cao cht lng ca cc thit k sau:

Thit k h thng v tuyn

Thit k h thng anten

Dng dng tn hiu iu ch thch hp

Mi trng, cc ta nh cng nh hng ln ti qua trnh truyn sng

Ngoi ra cn c cc can nhiu ln nhau gia cc k thut khc nhau. V d

chun IEEE 802.15.1 Blutooth c th can nhiu ci chun IEEE 802.11b/g.

1.5.2 Cc cng ngh khng dy

C nhiu giao thc khng dy, c s dng kh rng ri l IEEE 802.15.1

(Blutooth), IEEE 802.11 a/b/g/n wireless LAN, IEEE 802.15.4 (ZigBee), Man-scope

IEEE 802.16 (WiMax) v k thut nhn dng bng sng v tuyn (RFID).

Mi tiu chun c cc u im v hn ch ring. Hnh 1.6 m t vi giao thc

truyn dn khng dy

Hnh 1.6. th so snh cc giao thc truyn dn khng dy ph bin



26/71


t tnhIEEE Satndard

802.11 802.15/Blutooth 802.15.4/ZigbeeKhong cch ~100m ~10 100m ~10m

Tc d liu ~2 54 Mbps ~1 3 Mbps ~0,25 Mbps

Cng sut tiu th Trung bnh Thp Cc thpThi gian sng ca pin Pht vi gi Gi - vi ngy Ngy vi nmKch thc Ln Nh hn Nh nht

T s chi ph/ phc tp >6 1 0,2Bng 1.3 So snh cc giao thc

RFID l mt dang cm bin khng dy, khng yu cu cng sut cho cc th

qut. Th RFID l cm bin, n p ng li khi cng sut t u c hng n n.

Cc th RFID lu tr c 96bit d liu, nhng c th mi hn c th cung cp ln

n 128 hay 256 bit.1.5.2.1 Bluetooth

Bluetooth l mt cng ngh khng dy khng dy cho php cc thit b in,

in t giao tip vi nhau bng sng radio qua bng tn chung ISM (Industrial,

Scientific, Medical) 2.4 GHz. Nm 1994 hng Ericsson xut vic nghin cu v

pht trin giao din v tuyn cng sut nh, chi ph thp, s dng sng v tuyn

kt ni khng dy gia cc thit b di ng vi nhau v cc thit b in t khc, t

chc SIG (Special Interest Group) chnh thc gii thiu phin bn 1.0 ca

Bluetooth vo thng 7 nm 1999. Gn y, d n IEEE 802.15.1 pht trin PAN

khng dy da trn Bluetooth v1.1. K thut ny c mt s c tnh hn ch do

kh nng ng dng cho mng WSN b gii hn.

c im Bluetooth l cng sut tiu th thp, gi thnh thp, cung cp cho

ng dng khng dy gia cc thit b di ng v lm n gin kt ni gia cc thit

b. H thng dng sng radio pht ng hng c th xuyn qua tng v cc vt cn

khc. Bluetooth dng k thut tri ph song cng hon ton. Khi kt ni im im,

cho php cng lc kt ni ti a vi 8 thit b ng thi.

ng lu cng ngh Bluetooth mi ra i c cc c im tt hn:

Cho php cc thit b kt ni tm thi khi cn thit

Tc truyn nhanh gp 3 ln cc cng ngh Bluetooth trc

Cng sut tiu th gim xung do gim chu k hot ng

H tr giao thc TCP/IP v OBEX



27/71


S n gim trong cc ng dng a ng bi v bng thng tng ln

Chm tng thch vi cc version mi hn

Ci thin t l li bit

1.5.2.2 WLAN

Wireless LAN (Wireless Local Area Network) s dng sng in t (thng

l sng radio hay tia hng ngoi) lin lc gia cc thit b trong phm vi trung

bnh. So vi Bluetooth, Wireless LAN c kh nng kt ni phm vi rng hn vi

nhiu vng ph sng khc nhau, do cc thit b di ng c th t do di chuyn

gia cc vng vi nhau. Phm vi hot ng t 100m n 500m vi tc truyn d

liu trong khong 11Mbps-54Mbps.

Mng WLAN tc cao hn cung cp cho s lng ln ngi dng

vi mt cao. Chun IEEE 802.11g/n vn thit cho ng dng bng thng

rng v cao

Cung cp QoS (cht lng dch v) cao qua giao tip khng dy.

Chun IEEE 802.11e l k thut cung cp QoS cn thit

Bo mt thng tin l nhu cu ln. Chun IEEE 802.11i p ng tt

yu cu ny

Hnh 1.7.M hnh WLAN kt hp vi mng LAN truyn thng

Phn chia tn s hot ng trong m hnh mng WLAN nh trn hnh 1.7. Ccthit b di ng kt ni vi mng LAN thng qua cc thit b giao tip c th kt ni



28/71


vi mng LAN c dy thng qua Ethernet Switch. WLAN c nhiu chun theo IEEE,

mi chun p ng c cc yu cu khc nhau v c phn chia mt vng tn s

nht nh

Hnh 1.8.Bng tn IEEE 802.11b/g

Trn hnh 1.7, nu phn chia theo dng khng chng ln trong ton dy ta c 3

4 knh tn s. Dng th 2 l chia c chng ln. Hnh 1.8 cho thy s phn chia cc

dy tn s chun WLAN IEEE 802.11b/g. Cc ph ny lnh so le nhau 5MHz, dy

gm 14 khong tn s.

Bng 1.4 So snh 2 chun thng dng

802.11b/802.11g 802.11aBng thng 83.5MHz 300MHz

Tn s hot ng 2,4 2,48GHz

5,15 5,35GHz

5,725 5,825GHzS knh khng chng ln 3 4

Tc d liu 1;2;5,5;11;54Mbps 6;9;12;18;24;36;48;54Mbpsiu ch DSSS OFDM

1.5.2.3 ZigBee

ZigBee l mt cng ngh c xy dng da trn tiu chun ca IEEE, p

ng cho s pht trin rng khp ca mng WSN gi thnh thp, cng sut tiu th

thp dng cho cc ng dng iu khin t xa, iu khin thit b trong nh, ng dng



29/71


trong cc ta nh t ng trong cng nghip v thng mi. Cc chun mng khng

dy c gii thiu phn trn dng cho cc ng dng tc d liu cao tiu th

cng sut ln, phc tp v gi thnh cao. Tuy nhin, c nhiu ng dng mng khng

dy trong gim st c iu khin trong cng nghip v thng mi i hi thi gians dng pin di hn, tc d liu thp v phc tp t hn cc chun khng dy

khc. p ng cho s pht trin theo hng thng mi cn c mt chun tha

thun cc yu cu v tin cy cng nh an ninh, cng sut thp v gi thnh thp.

Cc ng dng khng dy nh th pht trin bi IEEE. Tiu chun IEEE

802.15.4 cung cp chun tc d liu thp vi thi gian s dng pin nhiu thng

n nhiu nm v t phc tp. Ci tn ZigBee c xut pht t cch m cc con ong

mt truyn nhng thng tin quan trng vi cc thnh vin trong t ong. l kiu

lin lc Zig-Zag ca loi ong honeyBee. V nguyn l ZigBee c hnh thnh

t vic ghp hai ch ci u vi nhau. Vic cng ngh ny ra i chnh l s gii

quyt cho vn cc thit b tch ri c th lm vic cng nhau gii quyt mt

vn no

T chc ZigBee Alliance a ra cc thng s ZigBee u tin vo nm 2004,

to tin cho s pht trin v ng dng rng ri ca mng WSN. zigBee/IEEE

802.15.4 c hi vng tr thnh cng ngh dn u cho s ng dng thng mi t

ta nh t ng cho n cng nghip v ng dng ti nh

Tiu chun hng n hot ng mt bng tn quc t. Chun ny quy nh

v lp vt l (PHY) v iu khin truy nhp (MAC), cc chc nng c dnh ngha

bi ZigBee Alliance c dng cc lp cao hn. Hnh 1.9 biu din cu trc cc

lp giao thc ca ZigBee



30/71


Hnh 1.9.M hnh giao thc ZigBee

So snh u im ca ZigBee vi Bluetooth

ZigBee cng tng t nh Bluetooth nhng n gin hn, ZigBee c tc d

truyn d liu thp hn, tit kin nng lng hn. Mt node mng ZigBee c kh

nng hot ng t 6 thng dn 2 nm ch vi ngun l 2 acqui AA.

Phm vi hot ng ca ZigBee l 10 75m trong khi Bluetooth ch l 10m (trong

trng hp khng c khuch i).

ZigBee sp sau Bluetooth v tc truyn d liu. Tc truyn d liu ca

ZigBee l 250Kbps ti 2,4Ghz, 40kbps ti 915MHz v ti 20Kbps ti 868MHz trong

khi tc ca Bluetooth l 1Mbps.

ZigBee s dng cu hnh ch - t c bn ph hp vi mng hnh sao tnh

trong c cc thit b giao tip vi nhau thng qua cc gi tin nh. Loi mng ny

cho php ti a ti 254node mng. Giao thc Bluetooth phc tp hn bi loi giao

thc ny hng ti truyn file, hnh nh, thoi trong cc mng ad hoc (ad hoc l mt

loi mng t trng cho vic t chc t do, tnh cht ca n l b hn ch v khng

gian v thi gian). Node mng s dng ZigBee vn hnh tn t nng lng, n c th

gi v nhn cc gi tin trong khon 15sec trong khi thit b Bluetooth ch c th lm

vic ny trong khong 3sec.

1.6 Cc yu t nh hng n mng WSN

1.6.1 Thi gian sng bn ngoiCc nt WSN vi ngun nng lng pin gii hn. V d: mt loi pin kim

cung cp 50Wh nng lng, n c th truyn cho mi nt mng ch tch cc

gn 1 thng hot ng. S tiu tn v tnh kh thi ca gim st v thay th pin cho

mt mng rng, th thi gian sng di hn c thit k. Trong thc t, pin rt cn

thit trong rt nhiu ng dng bo m mng WSN c th t ng s dng cn

thay th trong vi nm. S ci thin ca phn cng trong thit k pin v k thut thu

nng lng s gip ta mt phn trong vic tit kim pin



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1.6.2 Tiu th ngun mc thp

Cc ng dng mng cm bin khng dy in hnh yu cu cc thnh phn vi

ngun tiu th trung bnh, thc cht thp hn hin ti c cung cp trong cc b

xung ca cc mng khng dy hin ti ging nh Bluetooth. V d cc thit b chocc kiu cm bin cng nghip v y t, cc nhn thng minh, cc huy hiu, c cp

ngun t cc ngun pin nh, thi gian tiu th mt vi thng n mt vi nm. Cc

ng dng bao gm gim st v iu khin thit b cng nghip yu cu thi gian sng

ca ngun pin di duy tr s tn ti a v vo thit b c gim st khng c

tha thun. Cc ng dng khc, ging nh gim st mi trng cc vng rng, c th

yu cu mt s lng ln cc thit b nn khng th thay i ngun thng xuyn.

Hn na, cc ng dng no khng th tn dng mt ngun cho tt c; cc node

mng trong cc ng dng ny phi nhn ngun nng lng nh qu trnh khai thc v

lc nng lng t mi trng. Mt v d ca kiu ny l cm bin p sut lp xe,

mong mun nhn c nng lng t cc ngun nng lng c hoc nhit hin din

trong cc lp t thay v mt ngun c th yu cu c thay th trc khi lp chy.

b xung cho mc tiu th ngun trung bnh, cc ngun nng lng chnh

vi kh nng ngun nng lng trung bnh thng c cc kh nng ngun nng

lng nh gii hn; thc t ny c quan tm trong thit k h thng

1.6.3 Chi ph thp

V mng cm bin bao gm mt s lng ln cc node cm bin nn chi ph

sn xut mt node rt quan trng nh hng n gi thnh ton mng. Nu chi ph

ca mng cao hn so vi vic pht trin cc cm bin truyn thng th mng cm

bin l khng chp nhn c. Nh vy, gi thnh mt node cm bin cn phi gi

mc thp. Hin nay, chi ph sn xut ca mt node cm bin phi thp hn 1Dollarth mng mi c th thc hin c. Cc node cm bin ngoi cc thnh phn chnh

l b cm bin chuyn dng, h thng thu pht v tuyn, b x l, ngun nui, cn

phi trang b thm cc thit b khc c kh nng tm v tr, di ng, to nng

lng, v.v... tu theo ng dng c th. Do , chi ph sn xut tr thnh mt thch

thc khi mt khi lng cc chc nng c gii hn trong gi thnh thp hn 1

Dollar.



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1.6.4 Thng lng d liu

Khi cp ngay u tin, cc mng cm bin khng dy c gii hn v cc

yu cu thng lng d liu khi so snh vi Bluetooth (IEEE 802.15.1) v vi cc

mng WPAN v WLAN khc.Vi cc mc ch thit k, tc d liu mong muncc i, khi tnh ton trung bnh qua m chu k mt gi, c th thit lp l 512b/s (64

byte/s), d vy phc ha ny c phn tu tin. Tc d liu in hnh c mong

i c ngha ng k di iu ny; c th 1 b/s hoc thp hn trong mt vi ng

dng. Ch rng y l thng lng d liu, khng phi l tc d liu ban u

khi truyn pht qua knh, c th cao hn ng k.

Lng thng lng d liu c yu cu thp ny gi rng vi nhiu s

lng overhead giao thc c ch (v d cc header, trng a ch,v.v), hiu qu

truyn thng ca mng s rt thp c bit khi so snh ngc li vi mng gi cc

gi TCP/IP c th di 1500 byte. Khng c vn g khi thit k c la chn, hiu

qu s rt thp, v trong tnh th , c th c nhn thy mt cch r rng: ngi

thit k giao thc c kh nng phc ho t mi quan tm hiu qu truyn thng,

thng l mt tham s quyt nh trong thit k giao thc.

1.6.5 Bo mt

Bo mt trong mng cm bin khng dy c hai vn c gi tr quan trng -

bo mt thc t mng nh th no v bo mt mng nh th no c nhn bit do

ngi s dng v (c bit) l ngi s dng tim nng. Vic nhn bit bo mt l

vn quan trng bi v ngi s dng c mt mi lo t nhin l khi d liu ca h

(hoc bt c th g c th) c truyn dn qua khng kh cho bt c ai nhn.

Thng, mt ng dng tn dng mng cm bin khng dy thay th mt phin bn

c dy m ngi s dng c th nhn thy t nhin cc dy dn hoc cc cp tithng tin, v bit, chc chn hp l, rng khng c ai cng c th nhn c thng

tin hoc xen thng tin sai lch vo chng n ni nhn. ng dng khng dy phi

lm vic chim li tin cy m bo vi th trng rng ln c yu cu vi

chi ph thp hn.

Tuy nhin, bo mt hn na l qu trnh m ho ng bn tin. Thc t, trong

nhiu ng dng, qu trnh m ho (qu trnh gi mt b mt hoc mt ring t bn

tin) khng phi l mt mc ch bo mt quan trng ca cc mng cm bin khng



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dy. Thng, cc mc ch bo mt quan trng l m bo rng nhiu bn tin c

nhn khng b sa i theo nhiu con con ng t ngi gi n vi ni dung .

Tuy nhin, iu g quan trng hn, my nghe trm c trn ng khng th

xen cc bn tin li hoc sa i vo mng cm bin khng dy, v d c thnguyn nhn do n bt v tt mt cch ngu nhin. Cc yu cu ny l mt kiu bo

mt th hai, qu trnh xc nhn ng bn tin hoc kim tra tnh nguyn vn ca bn

tin, m n c thc hin bi vic gn mt MIC (Message Integrity Code) ph thuc

bn tin v ngi gi vo bn tin c truyn pht. (Trong cc trng bo mt, MIC

thng c gii hn MAC (Message Authentication Code) nhng MIC c s

dng trong vn bn ny trnh c s xo trn c th vi lp MAC ca ngn xp

giao thc OSI). Ngi thu mong mun v ngi gi chia s mt kho, n c s

dng bi ngi gi to ra MIC ph hp vi ngi nhn ph chun tnh nguyn

vn ca bn tin v nh dng ngi gi. trnh replay attacks, trong mt my

nghe trm ghi nhn mt bn tin v truyn pht li n sau , mt b m hoc b

nh thi bn tin c gp li trong trng tnh ton MIC. Trong cch ny, khng c

hai bn tin xc thc - thm ch cha cng d liu - c nhn dng.

Cc mng cm bin c cc yu cu b xung, bao gm yu cu cho t l phn

chia n cc mng rng ln, dung sai li, v yu cu vn hnh trong s a dng

rng ln trong cc mi trng i nghch mt cch hp l. Mc d vic thit k mt

mng nh vy nhn c cc yu cu c th coi nh l nn ch, ngi thit k

ca mt mng cm bin khng dy khng cn cc cng c. Cc yu cu v ngun v

chi ph cht ch hnh thnh cc yu cu khn bt buc trong cc phm vi khc

1.7 ng dng ca mng WSN

WSN l tp hp cc kch thc nh gn, c th l cc node cm bin vi githnh thp, c kh nng lm vic trong iu kin mi trng t nhin hoc o c

cc thng s khc v a ra thng tin n trung tm cho cc x l ph hp. Cc node

trong mng WSN c th lin lc vi cc node xung quanh n v cn c th c cc x

l d liu thu c trc khi gi n cc node khc.WSN cung cp rt nhiu cc ng

dng hu ch.

Trong nhng nm gn y, cc nghin cu v WSN t c bc pht

trin mnh m, cc bc tin t cc nghin cu ha hn tc ng ln n cc ng



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dng rng ri trong lnh vc an ninh quc gia, chm sc sc khe, mi trng, an

ton nng lng, an ton thc phm v sn xut

Mt s ng dng c bn ca WSN

Cm bin mi trngo Qun s: pht hin mn, cht c, dch chuyn qun i

o Cng nghip: h thng chiu sng, m, phng chy, r r

o Dn dng: h thng iu ha nhit , nh sng

Cm bin iu khin

o Qun s: kch hot thit b, v kh qun s

o

Cng nghip: iu khin t ng cc thit b, roboto Mi trng: gim st l lt, gi, ma, pht hin nhim

o Y t: theo di bnh nhn, h thng bo ng khn cp

H thng giao thng thng minh

o Giao tip gia cc bin bo v phng tin giao thng, h thng

iu tit lu lng cng cng, kt xe

o H thng nh v, tr gip iu khin t ng phng tin giao

thng

Gia nh

o Nh thng minh: h thng cm bin, giao tip v iu khin cc

thit b di ng

WSN to ra mi trng giao tip gia cc thit b thng minh, gia cc thit b

thng minh v con ngi, giao tip gia cc thit b thng minh v cc h vin thng

khc (h thng thng tin di ng, internet...)

CHNG 2:NH TUYN TRONG MNG CM BIN KHNG DY

Do nhng c im ring bit m nh tuyn trong mng cm bin khng dy

phi i mt vi rt nhiu vn . Rt nhiu cc gii thut mi c a ra gii

quyt vn nh tuyn d liu. Cc thut ton phi p ng c cc yu cu v



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ng dng v cu trc, cng nh cc c im ring ca mng. Chng ny trnh by

ba loi giao thc thng c dng trong mng cm bin, l nh tuyn trung tm

d liu (data centric protocol), nh tuyn phn cp (hierarchical protocol) v nh

tuyn da vo v tr (location based protocol).2.1 Gii thiu

Mc d mng cm bin khng dy c kh nhiu im tng ng so vi cc

mng adhoc c dy v khng dy nhng chng cng c mt s cc c tnh duy nht

m to cho chng thnh mng ring. Do vy n yu cu thit k cc giao thc nh

tuyn mi m khc xa so vi cc giao thc nh tuyn trong cc mng adhoc c dy

v khng dy.

2.2 s phn phi v tp hp d liu

Mng WSN c kh nng ng dng rng ri trong gim st v iu khin nh

hnh 2.1. Cc d liu c thng tin gia cc trm trung tm v cc node phn b l

mt kha cnh quan trng v c bn ca WSN

Hnh 2.1.Cc ng dng mng WSN

Cch n gin thc hin l trao i trc tip t t cc node n base. Tuy

nhin, lin kt da trn truyn mt chng (single-hop) gp vn suy gim nng

lng nhanh chng ca cc node nu cch xa trm trung tm, do lm gii hn thigian sng ca mng. y l vn quan trng i vi cc mng cm bin khng dy



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c xy dng phn b trn phm vi rng hay cc node di ng c th di chuyn ra

xa trm trung tm.

gii quyt nhc im ny, d liu trao i gia cc cm bin v base

station c truyn a chng (multihop). Cc lin kt a chng c th ko di khongcch v a ra mt ng i linh hot hn. Phng php ny tit kim hiu qu nng

lng v gim ng k can nhiu gia cc node ang tranh chp truy cp knh

truyn, c bit trong nhng mng WSN c mt cao. M hnh truyn d liu c

minh ha trong hnh 2.2. Gi yu cu c pht i, cc node p li bng gi tr li

hoc p ng cc s kin xy ra, d liu thu thp t cc node cm bin phi i qua

nhiu chng n trm trung tm.

Trong truyn multihop, cc node trung gian phi tham gia co vic chuyn cc

gi d liu gia ngun v ch. Xc nh cc node trung gian cn phi i qua l

nhim v ca gii thut nh tuyn. nh tuyn trong mng c ln gp nhiu kh

khn, thit k phi m bo s chnh xc, tnh n nh v kh nng ti u. Cng vi

cc c tnh ca mng WSN nh tit kim nng lng v bng thng hn ch to

nhiu thch thc cho gii thut nh tuyn tha mn yu cu lu lng v ko di

thi gian sng ca mng.

Hnh 2.2.Truyn d liu a chng

2.3 Thch thc trong vn nh tuyn

2.3.1 Tnh ng ca mng

Mng cm ng bao gm ba phn chnh, l cc node cm ng, node sink v

cc s kin cn gim st. Tr mt vi trng hp thit lp cc node cm ng di ng,



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cn li hu ht cc node cm bin c gi thit c nh. Tuy nhin trong mt s ng

dng, c node gc v cc node cm bin c th di truyn, khi cc bn tin chn

ng c ly t cc node di ng hay c chuyn n cc node di ng s phi

i mt vi nhiu vn hn nh ng lin lc, cu hnh mng, nng lng, rng bng Cc s kin cm nhn c th l tnh hoc ng, ty thuc vo cc ng

dng.

2.3.2 S trin khai cc node

Vic phn b node trong WSN ph thuc vo ng dng v c th c xc

nh trc hoc phn b. Trong trng hp c xc nh trc, cc node c t

bng tay v d liu c nh tuyn thng qua cc ng nh. Tuy nhin trong

cc h thng t t chc, cc node cm ng c phn b ngu nhin, to ra mt cu

trc theo kiu ad hoc. Trong cc cu trc , v tr ca cc sink hay l cc node ch

cng gp phn khng nh vo vic s dng hiu qu nng lng v hot ng ca

mng. Trong hu ht cc cu hnh mng, lin lc gia cc node cm bin thng c

c ly ngn do cc hn ch v nng lng v bng thng, do vic chn ng s

thc hin qua nhiu bc nhy.

2.3.3 Ti nguyn hn ch

Cc node cm bin c thit k vi phc tp t nht v gi thnh thp

p ng cho cc mng c ln. Nng lng l vn quan tm nhiu nht trong mng

WSNs, phi to ra hot ng lu di trong iu kin ngun pin hn ch. Truyn a

ng qua mng khng dy chnh l ngun gy tiu tn cng sut nhiu nht. Vn

qun l ngun nng lng tr thnh mt thch thc vi mng WSN trong nhiu ng

dng quan trng

Cc kiu d liu trao i gia cc node ph thuc vo c im ring ca tngng dng c th. C nhng ng dng yu cu thu thp d liu theo chu k hay khi c

s xut hin ca node s kin no . Trng hp khc d liu li c tp hp, lu

tr, x l bi mt node sau c chuyn tip cho cc node khc. i vi mng

qui m ln, s lng ln node cm bin phn b trn khu vc rng, cc kiu d liu

phc tp cn c cc giao thc nh tuyn ti u m bo cht lng thng tin v

thi gian s dng ca mng. Do thit k gii thut nh tuyn hiu qu l yu cu



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quan trng m bo kh nng m rng qui m v tnh n nh ca mng WSNs cng

nh s pht trin mnh m cc ng dng trong tng lai.

2.4 Phn loi v so snh cc giao thc nh tuyn trong WSN

C nhiu cch phn loi cc giao thc chn ng trong WSN. Ngoi cch

chia lm ba loi nh cp trn, l nh tuyn trung tm d liu, nh tuyn

phn cp v nh tuyn da vo v tr vic chn ng trong WSN cn c th c

chia thnh chn ng ngang hng, chn ng phn cp v chn ng da theo v

tr tu thuc vo cu trc mng. Nhng giao thc ny cng c th c chia thnh

cc giao thc chn ng a ng, yu cu hi/p, lin kt hoc da vo cht

lng dch v -QoS tu theo c ch hot ng ca giao thc. Ngoi ra, cc giao thc

chn ng c th c chia thnh ba loi l ch ng, tng tc hoc ghp tu

thuc vo cch thc m ngun tm ng ti ch. Trong cc giao thc ch ng, tt

c cc ng c tnh ton trc khi c yu cu, trong khi i vi cc giao thc

tng tc th cc ng c tnh ton theo yu cu. khi qut, c th s dng

phn loi theo cu trc mng v c ch hot ng ca giao thc (tiu chun chn

ng). Vic phn loi v so snh cc giao thc chn ng trong WSN c ch ra

trong hnh 2.2 v hnh 2.3

Hnh 2.3.Phn loi giao thc chn ng trong WSN

Giao thc

chn ng

i

Phn loiDi

chuyn

Tit

kim

cng

sut

Da

vo hi/

p

Kt hp

s liu

Xc

nh v

tr

Qos

phc

tp ca

trngthi

Kh nng

nh c

a

ng

Da

vo yu

cu



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SPINNgang

hngC th

Hn

chC C Khng Khng Thp Hn ch C C

GBRNgang

hng

Hn

ch

Khng

p dngKhng C Khng Khng Thp Tt Khng C

MCFANgang

hngKhng

Khng

p dngKhng Khng Khng Khng Thp Tt Khng Khng

CADR Nganghng

Khng Hnch

Khng C Khng Khng Thp Hn ch Khng Khng

GUGARNgang

hngKhng

Hn

chKhng C Khng Khng Thp Hn ch Khng C

ACQUITRENgang

hng

Hn

ch

Khng

p dngKhng C Khng Khng Thp Hn ch Khng C

EARNgang

hng

Hn

ch

Khng

p dngKhng Khng Khng Khng Thp Hn ch Khng

C

LEACH Phn cpNt gc

c nhCc i Khng C C Khng

Nt ch

nhmTt Khng Khng

TEEN&

APTEENPhn cp

Nt gc

c nhCc i Khng C C Khng

Nt ch

nhmTt Khng Khng

PEGASIS Phn cp

Nt gc

c nh Cc i Khng Khng C Khng Thp Tt Khng KhngMECE&

SMCENPhn cp Khng Cc i Khng Khng Khng Khng Thp Thp Khng Khng

OP Phn cp KhngKhng

p dngKhng Khng Khng Khng Thp Thp Khng khng

HPAR Phn cp KhngKhng

p dngKhng Khng Khng Khng Thp Tt Khng Khng

VGA Phn cp KhngKhng

p dngC C C Khng

Nt chu

nhmTt C Khng

GAFDa theo v

trKhng

Hn

chKhng Khng Khng Khng Thp Tt Khng Khng

GEARDa theo v

tr

KhngHn

ch

Khng Khng Khng Khng Thp Hn ch Khng Khng

SARDa theo v

trKhng

Khng

p dngC C Khng C

Trung

bnhHn ch Khng C

SPEEDDa theo

QosKhng

Khng

p dngKhng Khng Khng C

Trung

bnhHn ch Khng C

Bng 2.1 Phn loi v so snh cc giao thc chn ng trong WSN

2.5 Giao thc nh tuyn trong WSN

nh tuyn trong WSN gp kh khn ln l to s cn bng gia nhy v

tnh hiu qu. S cn bng gia c tnh gii hn kh nng x l v thng tin ca ccnode cm bin vi phn overhead cn thit. Trong WSNs overhead (c th coi l chi

ph cho qun l) c tnh da trn bng thng s dng, cng sut tiu th v yu

cu x l node di ng. V nu overhead qu ln gy lng ph nng lng, bng thng,

thi gian x l, tng tr gi tin node nhng cht lng d liu tt hn. Ngc li,

overhead nh th thi gian x l, bng thng, tr thp tuy nhin cht lng c th

gim. Thch thc ca giao thc nh tuyn chnh l tm ra gii thut cn bng

nhng yu cu ny.



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2.5.1 Cc k thut nh tuyn

Thit k cc giao thc nh tuyn ca mng WSN phi xem xt n cng sut

v ti nguyn hn ch ca cc node mng, c tnh thay i theo thi gian ca knh

truyn v tuyn v kh nng tr hay mt gi. Nhiu giao thc nh tuyn c ara.

Dng th nht l giao thc dnh cho kin trc mng phng trong tt c cc

node xem nh cng cp. Kin trc phng c nhiu li ch nh ti thiu overhead

xy dng h tng mng v c kh nng tim ra nhiu ng lin lc gia cc node vi

sai s cho php.

Dng th hai dng trong mng c cu trc tit kim nng lng, n nh v

kh nng m rng. Trong dng ny cc node mng c sp xp vo cc cluster,

trong mt node c nng lng ln nht vai tr cluster head. Cluster head c trch

nhim phi hp cc hot ng gia cc node trong cluster v chuyn thng tin gia cc

cluster. Vic phn hoch gim nng lng tiu th v ko di thi gian sng ca

mng.

Dng th ba dng phng php data-centric phn b yu cu trong mng.

Phng php da trn thuc tnh, mt node ngun truy vn n mt thuc tnh

ca hin tng no hn l mt node cm bin ring bit. Vic phn tn yu cu

thc hin bng cch phn nhim v cho cc node cm bin v nh r mt thuc tnh

ring bit cho cc node. Cc kiu thng tin c th dung nh broadcasting, attribute-

based, multicasting,geo-casting v anycasting.

Dng th t dng v tr ch ra mt node cm bin. nh tuyn da trn v

tr rt hu ch cho cc ng dng m v tr ca node trong mt vng a l c th c

hi bi node ngun. Yu cu nh th c th nh r vng no m cc hin tngquan tm c th xy ra hay ln cn vi im c bit no trong vng hot ng

ca mng.

2.5.1.1 Flooding v cc bin th

Flooding l mt k thut chung thng dng trong pht tn thng tin v tm

ng trong mng c dy v khng dy ad hoc. Chin thut nh tuyn n gin v

khng i hi cu hnh mng tn km v thut ton tm ng phc tp. Flooding

dng phng php reactive (phn ng li), khi mi node nhn c mt gi iu



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khin hay d liu n s gi n tt c cc node xung quanh n. Sau khi truyn, mt

gi i theo tt c cc ng c th c. Nu khng b mt kt ni, gi s n ch.

Hn na, khi cu hnh mng thay i, vic truyn gi s theo nhng tuyn mi. Hnh

2.3 minh ha qui c flooding trong mng. Flooding dng n gin nht c th lmcc gi b sao chp li mt cch khng gii hn khi i qua cc node mng.

Hnh 2.4.Fooding cc gi d liu trong mng thng tin

ngn chn mt gi tin i vng khng xc nh trong mng, mt trng gi

l hop count c them v gi. u tin,hop count c t gi tr sp s ng knh

mng. Khi gi i qua mng,hop count b gim i 1 sau mi bc (1 bc c tnh

t 1 ln truyn t node ny sang node kia). Khi hop count v 0,gi s b b i. Mt

cch tng t c dng l thm vo trng time-to-live,trng ny ghi li thi gianm gi c php tn ti trong mng, khi ht thi gian ny, gi khng c truyn i

na. Flooding c th c ci tin bng cch x nhn gi d liu duy nht, mi node

mng s b i cc gi nhn ri.

Mc d s n gin trong qui lut hot ng v ph hp vi cu hnh mng c

chi ph thp nhng flooding gp nhiu bt li khi p dng cho mng WSNs. Nhc

in u tin ca flooding l gp phi vn traffic implosion (bng n hay khp kn



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qung b n tt c cc node, gossiping ch yu cu mi node gi gi va nhn c

n mt node c la chn ngu nhin. Khi nhn c gi, node ln cn li chuyn

tip gi n mt node la chn ngu nhin khc. Qu trnh c tip tc n khi gi

n c ch n hay hop count b gii hn. Gossiping trnh c vn bng nlu lng mng bng cch gii hn s gi m mi node gi n cc node ln cn n.

Tuy nhin tr gi ti ch n c th rt ln, c bit trong mng c kch thc ln

do bn cht, ch c mt lin kt c to thnh ti mt thi im.

2.5.1.2 Giao thc nh tuyn thng tin qua s tha thun

Giao thc thng tin qua s tha thun gia cc node (SPIN) l h cc giao

thc da trn tha thun pht thng tin trong mng WSN. i tng chnh ca cc

giao thc ny l tnh hiu qu ca vic pht thng tin t mt node no n tt c

cc node khc trong mng. Cc giao thc n gin nht l flooding v gossiping.

Flooding i hi mi node gi mt bn sao gi d liu n tt c cc node ln cn

vi n cho n khi thng tin n c ch. Gossiping dng tnh ngu nhin gim

s bn sao v yu cu ch c mt node nhn mt gi d liu v sau chuyn

tip mt cch ngu nhin n mt node c chn trc.

S n gin ca flooding v gossiping do qui lut hot ng n gin v

khng i hi cu hnh phc tp. Tuy nhin, c im cc giao thc ny l s tr gi

lm gim cht lng mng v lu lng ti, gy ra bi s bng n cc gi v chng

ln cc gi trong cng vng phn b. Cc giao thc n gin nh flooding v

gossiping khng tnh n ngun nng lng hin ti lm gim mt cch ng k thi

gian sng ca mng. i tng chnh ca nhm giao thc SPIN l gii quyt hn ch

ca cc giao thc truyn thng. Nguyn l c bn ca h giao thc ny l tha thun

d liu v s thch nghi ti nguyn mng. Tha thun d liu (data negotiation) yucu cc node phi hc ni dung ca d liu trc khi pht d liu gia cc node

mng. SPIN dng cc gi nh l m t trc khi pht gi d liu thc. Cc node thu

khi nhn c gi qung co nu mun nhn gi d liu thc phi gi mt gi yu

cu cho node ngun. Do gi d liu thc ch c gi cho cc gi quan tm, hn

ch kh nng b bng n gi nh trong flooding v gim ng k lu lng d tha

trong mng. Ngoi ra vic dng kha m t d liu (meta data descriptors) loi tr

kh nng chng ln v cc node ch yu cu d liu cn quan tm.



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S thch ng ti nguyn mng (Resource adaptation) cho php cc node dng

giao thc SPIN iu chnh hot ng theo trng thi hin nng lng hin ti. Mi

node trong mng c th theo di s tiu th nng lng trc khi pht hay x l d

liu. Khi mc nng lng xung thp, node s gim hay ngng hon ton cc hotng nh chuyn tip gi cho cc node khc. Vic ny s c cc node cn nng

lng nhiu hn thc hin. SPIN gip ko di thi gian sng ca node.

SPIN thc hin vic tha thun v truyn d liu thng qua 3 dng thng

ip. u tin l gi ADV, c dng qung co cho gi d liu mi m node

mun pht. Node c d liu s pht cc gi ADV cha m t d liu thc n cc

node xung quanh. Dng th 2 l gi REQ, c dng yu cu node ngun pht gi

d liu qung co trc . Mt node mng nhn c gi ADV v th hin

mong mun nhn gi d liu thc bng cch pht i thng ip REQ. Dng th 3 l

DATA, cha d liu thc. Gi DATA thng ln hn cc gi ADV v REQ. Vic

hn ch cc gi d tha lm gim ng k nng lng tiu th ti cc node.

Hnh 2.7.Hot ng c bn ca giao thc SPIN



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Hot ng c bn ca giao thc SPIN c minh ha trn hnh 2.7. Node

ngun l A, pht gi ADV qung co gi d liu m n mun pht. Node B nhn

c gi ADV ny. Node B th hin mong mun nhn gi d liu c qung co

theo nh m t trong gi ADV. V th B gi gi REQ cho A. Sau A gi gi dliu thc cho B. Node B sau khi nhn d liu li pht gi ADV cho cc node

C,D,E,F,G. Ch c 3 node C,E,G quan tm n gi ny. Cc node ny pht thng ip

REQ cho node B. Ngay sau B gi d liu cho C,E,G. Qu trnh din ra cho n

khi gi d liu n c ch mong mun.

Hnh 2.8.Th tc bt tay trong giao thc SPIN-PP

Dng n gin nht ca h giao thc SPIN l SPIN-PP, c thit k cho

mng lin lc im-im (point-to-point). Th tc bt tay ba bc nh trn hnh 2.8.

Bc 1, node A c d liu cn pht v th A pht gi ADV qung co cho gi d liu

thc ca mnh. Bc 2, node B quan tm n gi d liu thc lin gi gi REQ

yu cu d liu. Bc 3, node A p ng yu cu v gi gi d liu thc cho B.

Giao thc ny tha thun gia cc node trnh nguy c b bng n cc gi v vn

chng ln trong giao thc flooding v gossiping. Theo m phng hiu qu gp 3.5

ln so vi flooding. Giao thc cn t tc d liu cao gn ti u so vi l thuyt.

Mt loi khc l SPIN-EC, kt hp k thut quan st ngun nng lng datrn mc ngng. Mt node ch tham gia vo hot ng giao thc nu node c th

hon thnh tt c cc hot ng m khng lm gim nng lng di mc cho php.

Khi node nhn c mt gi qung co, n khng gi thng ip REQ nu n xc

nh ngun nng lng khng gi gi REQ v nhn gi DATA. Kt qu m

phng cho thy giao thc SPIN-EC tng 60% d liu trn mt n v nng lng so

vi flooding.



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C SPIN-PP v SPIN-EC iu c thit k cho lin lc im-dim. Mt loi

th 3, SPIN-BC c thit k cho mng qung b. Trong cc loi mng ny, tt c

cc node dng chung mt knh truyn. Khi mt node gi mt gi d liu qua knh

qung b, gi s c nhn bi tt c cc node khc trong phm vi ca node. Giaothc SPIN-BC khng yu cu cc node sau khi nhn thng ip ADV phi p li

ngay lp tc gi REQ. Thay vo node ch mt khong thi gian, trong khi n

gim st knh truyn. Nu node nghe thy thng ip REQ c pht ra t mt node

khc (ngha l node kia mong mun nhn c gi d liu t node ngun), node s

hy gi yu cu ca n, do loi b kh nng cc gi REQ d tha trong mng. Khi

nhn c gi REQ t mt node no trong mng, node ngun s gi thng ip

DATA ch mt ln, mc d c th n nhn nhiu gi yu cu ging nhau t cc node

mng.

Hot ng c bn ca giao thc SPIN-BC c miu t trn hnh 2.9. Trong

m hnh ny, node c d liu l node A, gi mt gi ADV gii thiu d liu ca

n cho cc node ln cn. Tt c cc node nghe thy thng ip ny, nhng node C

pht trc gi REQ yu cu gi d liu t node A. V y l gi pht qung b

nn cc node B v D nghe c gi ny v ngng vic pht gi REQ ca n. Node E

v F khng quan tm v b qua cc gi ny. Khi nghe c gi REQ t node C, node

A pht gi d liu cho C. Tt c cc node iu nhn c gi ny. Trong mi trng

qung b, SPIN-BC gim hao ph nng lng bng cch hn ch cc gi d tha

trong mng.

Hnh 2.9.Giao thc SPIN BC

Giao thc cui cng thuc h SPIN l giao thc SPIN-RL, pht trin t SPIN-BC ci thin tin cy v li thng ip do suy hao knh truyn. Cc gi ADV



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v REQ c pht qung b lp li theo chu k. Nu mt node gi yu cu nhn gi

d liu nhng sau khong thi gian rnh trc n vn cha nhn c th node s

yu cu li ln na. Hn na, tin cy ci thin cn do vic pht li gi m t d

liu metadata theo chu k. Cc node SPIN-RL hn ch s ln pht li thng ipDATA. Sau khi gi thng ip DATA, node ch ht mt khong thi gian trc khi

p ng cho nhng yu cu khc cho d liu tng t.

H giao thc SPIN ch ra cc nhc im chnh ca flooding v gossiping.

SPIN c hiu sut s dng nng lng v tc phn pht d liu cao hn flooding

v gossiping. Tuy nhin, s tha thun cc b c th khng bao bc ht ton

b mng tt c cc node c nhu cu iu nhn c gi qung b v sau l gi

d liu mong mun. Tnh hung c th xy ra nu cc node trung gian khng

quan tm n gi d liu v b qua thng ip ADV tng ng sau khi nhn c

gi ny.iu ny hn ch vic s dng SPIN trong cc ng dng c bit nh gim

st pht hin xm nhp v bo v cc cng trnh trng yu.

2.5.1.3 Truyn tin trc tip (Directed Diffusion)

y l giao thc trung tm d liu i vi vic truyn v phn b thng tin

trong mng cm bin khng dy. Mc tiu chnh l tit kim nng lng tng thi

gian sng ca mng t c mc tiu ny, giao thc ny gi tng tc gia cc

nt cm bin, da vo vic trao i cc bn tin, nh v trong vng ln cn mng. S

dng s tng tc v v tr nhn thy c tp hp ti thiu cc ng truyn dn. c

im duy nht ca giao thc ny l s kt hp vi kh nng ca nt c th tp

trung d liu p ng truy vn ca sink tit kim nng lng. Thnh phn chnh

ca giao thc ny bao gm 4 thnh phn: interest (thng tin yu cu), data message

(cc bn tin d liu), gradient, reinforcements. Directed disffusion s dng m hnhpublish- and subcribe trong mt ngi kim tra (ti sink) s miu t mi quan tm

(interest) bng mt cp thuc tnh-gi tr.

Hot ng ca Directed Diffusion

Sink s gi qung b bn tin interest theo chu k cho cc nt ln cn.

Bn tin ny s truyn qua tt c cc node trong mng nh l mt s quan tm

n mt d liu no . Mc ch ca vic thm d ny l xem xt xem c

node cm bin no c th tm kim d liu tng ng vi interest. Tt c



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cc node u duy tr mt interest cache lu tr cc interest entry khc nhau.

Mi mt mc (entry) trong interest cache s lu tr mt interest khc

nhau. Cc entry cache ny lu tr mt s trng sau: mt nhn thi gian,

nhiu trng gradient nhn c sau cng. Mi gradient s lu tr c tc d liu v chiu m d liu gi i, trng duration s xc nh khong thi

gian ca interest. Mi gradient c th coi nh l mt lin kt phi hi ca node

ln cn khi nhn c bn tin interest. Vic truyn bn tin interest trong ton

mng cng vi vic thit lp cc gradient ti mi node cho php vic tm ra v

thit lp cc ng dn gia sink a ra yu cu v d liu quan tm v cc

node m p ng mi quan tm .

Khi mt node pht hin mt s kin n s tm kim trong cache xem c

interest no ph hp khng, nu c n s tnh ton tc s kin cao nht cho

tt c cc gradient li ra. Sau n thit lp mt phn h cm bin ly mu

cc s kin mc tc cao ny, cc node s gi ra ngoi miu t v s kin

cho cc node ln cn c gradient. Cc node ln cn ny nhn d liu v s

kim tra trong cache xem c entry no ph hp khng, nu khng n s loi

b d liu cn nu ph hp n s nhn d liu cc node ny, s thm bn tinvo cache d liu v sau gi bn tin cho cc node ln cn



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Hnh 2.10.Hot ng c bn ca Directed Diffusion

Khi nhn c mt interest cc node tm kim trong interest cache ca n xem

c entry no ph hp hay khng, nu khng node s to mt cache entry mi.

Cc node s s dng cc thng tin cha trong interest to ra cc thng sinterest trong entry. Cc entry ny l mt tp hp cc trng gradient vi tc

v chiu tng ng vi node ln cn m interest c nhn. Nu nh

interest nhn c c trong cache th node s cp nht nhn thi gian v

trng duration cho ph hp vi entry, mt trng gradinet s c remove

khi entry nu qu hn. Trong pha thit lp gradient th cc sink s thit lp

mt tp hp cc dn ng, sink c th s dng ng dn ny vi s kin

cht lng cao lm tng tc d liu, iu ny t c thng qua mt

ng dn c h tr x l (path reinforcement process). Cc sink ny c

th s dng s h tr ca mt s cc node ln cn, lm c iu ny sink

c th gi li bn tin interest ngun tc cao thng qua cc ng dn

c chn, nh vic tng cng cc node ngun trn ng dn gi d

liu thng xuyn hn. Directed disffusion c u im nu mt ng dn

no gia sink v mt node b li, mt ng dn c tc d liu thp hnc thay th. K thut nh tuyn ny n nh di phm vi mng ng, loi

giao thc ny tit kim nng lng ng k.

2.5.1.4 LEACH (Low Energy Adaptive Clustering Hierarchy)

LEACH l giao thc phn cp theo cm thch ng nng lng thp. y l

giao thc thu lm v phn pht d liu ti cc sink c bit l cc trm c s.

Mc tiu chnh ca LEACH l:

M rng thi gian sng ca mng

Gim s tiu th nng lng bi mi node mng

S dng tp trung d liu gim bn tin truyn trong mng

LEACH thng qua m hnh phn cp t chc mng thnh cc cm, mi

cm c qun l bi node ch, node ch thc hin nhiu nhim v. u tin l thu

lm d liu theo chu k t cc nt thnh vin, trong qu trnh tp trung d liu nt

ch s c gng tp hp d liu gim d tha v nhng d liu ging nhau. Nhimv th hai l node ch s trc tip truyn d liu c tp hp li n cc



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trm c s, vic truyn ny thc hin theo kiu single hop. Nhim v th ba l

LEACH s to ra m hnh ghp knh theo thi gian TDMA (Time Division Multiple

Access), mi node trong cm s c gn mt khe thi gian m c th s dng

truyn tin.Cc nt ch s qung b m hnh TDMA cho cc nt thnh vin trong cm

ca n. gim thiu kh nng xung t gia ccnt cm bin trong v ngoi cm,

LEACH s dng m hnh truy cp a phn chia theo m CDMA.Qu trnh hot ng

ca LEACH c chia thnh hai pha l pha lp v pha n nh. Pha thit lp bao gm

hai bc l la chn nt ch v thng tin v cm. Pha n nh trng thi gm thu

lm d liu, tp trung d liu v truyn d liu n cc trm c s. Thi gian ca

bc n nh ko di hn so vi thi gian ca bc thit lp gim thiu mo u.

Tuy nhin LEACH cng c mt s nhc im sau:

LEACH cha xc nh c th c s lng ti u cc node chnh ca

mng khi m cc mng khc nhau v cu hnh, mt v s lng

node khc nhau.

Cha c gi v khi no th vic ti to li cc node chnh cn c

thc hin. Cc node chnh xa trm gc s tiu th nng nhiu nng lng hn

v nhanh chng ng hot ng hn cc node khc.

Tt c cc node c th kt ni vi trm gc qua mt chng c th

khng kh thi v kh nng v nng lng cung cp cho cc node thay

i theo thi gian.

Khong thi gian ca pha ng nh trng thi nh hng ln n nng

lng tiu th. Khong n nh trng thi ngn lm tng overhead (chi

ph cho iu khin giao thc), trong khi khong n nh trng thi ko

di lm st gim nng lng nhanh chng.

2.5.1.5 GAF(Geographic Adaptive Fidelity)

GAF d tr nng lng bng cch tt cc node khng cn thit trong mng m

khng nh hng n mc chnh xc ca nh tuyn, n to ra mt mng li o

cho vng bao ph. Mi node dung h thng nh v ton cu(GPS GlobalPoisitioning System) ca n, xc nh v tr kt hp mt im trn li c gi l



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trng ng khi tnh n vic nh tuyn gi, gi cc node nh v trong vng

li xc nh trng thi ngh tit kim nng lng. V vy GAF c th tng ng

k thi gian sng ca mng li cm ng khi m s lng cc node tng ln. V d

c a ra hnh 2.11, node 1 c th truyn n bt k node no trong s cc node2, 3 v 4 v cc node 2, 3, 4 c th truyn ti node 5. Do cc node 2, 3 v 4 l

tng ng v trong s 3 node c th trng thi ngh.

Hnh 2.11.V d v li o trong GAF

Cc node chuyn trng thi t ngh sang hot ng ln lt cho cc tic cn bng. C ba trng thi c nh ngha trong GAF, l pht hin

(discovery) xc nh cc node ln cn trong li, hot ng (active) th hin s

tham gia vo qu trnh nh tuyn v ngh (sleep) khi sng c tt i. iu khin

di ng, mi node trong li c on thi gian ri khi li ca n v gi thng

tin ny n node ln cn. Cc node ang khng hot ng iu chnh thi gian ngh

ca chng cho ph hp c th nhn c cc thng tin t cc node ln cn,

nh tuyn c chnh xc. Trc khi thi gian ri khi li ca cc node ang hot

ng qu hn, cc node ang ngh thot khi trng thi v mt trong s cc node

hot ng tr li. GAF c trin khai cho c nhng mng bao gm cc node

khng di ng (GAF c bn) v mng bao gm cc node di ng (GAF thch ng di

ng).

GAF gi mng hot ng bng cch gi cho cc nt i din lun ch

hot ng trong mi vng li o ca n. Mc d GAF l mt giao thc da trn vtr, n cng c th c coi l nh mt giao thc phn cp khi m cc cm da trn



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v tr a l. i vi mi vng li xc nh, mi node i in hot ng nh mt

node ch truyn d liu n cc nt khc. Tuy nhin nt ch ny khng thc hin

bt c mt nhim v hp nht hay tp trung d liu no nh trong cc giao thc phn

cp thng thng

Hnh 2.12.S chuyn ng trng thi trong GAF

2.5.1.6 GEAR (Geographic and Energy Aware Routing)

Giao thc GEAR (Geographic and Energy-Aware Routing) dng s nhn bit

v nng lng v cc phng php thng bo thng tin v a l ti cc node ln cn.

Vic nh tuyn thng tin theo vng a l rt c ch trong cc h thng xc nh v

tr, c bit l trong mng cm bin. tng ny hn ch s lng cc yu cu

Directed Diffusion bng cch quan tm n mt vng xc nh hn l gi cc yu cu

ti ton mng. GEAR ci tin hn Directed Diffusion im ny v v th d tr

c nhiu nng lng hn.Trong giao thc GEAR, mi mt node gi mt estimated cost v mt learned

cost trong qu trnh n ch qua cc node ln cn. Estimated cost l s kt hp ca

nng lng cn d v khong cch n ch. Learned cost l s ci tin ca estimated

cost gii thch cho vic nh tuyn xung quanh cc hc trong mng. Hc xy ra khi

m mt node khng c bt k mt node ln cn no gn hn so vi vng ch hn l

chnh n, trong trng hp khng c mt hc no th estimated cost bng vi learned

cost. Learned cost c truyn ngc li 1 hop mi ln mt gi n ch lm cho



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vic thit lp ng cho gi tip theo c iu chnh.

C 2 giai on trong gii thut ny:

Chuyn tip gi n vng ch: GEAR dng cch t chn nt ln cn da trn

s nhn bit v nng lng v v tr a l nh tuyn gi n vng ch.C2 trng hp cn quan tm:

Khi tn ti nhiu node ln cn gn hn so vi ch: GEAR s chn hop

tip theo trong s tt c cc node ln cn gn ch hn.

Khi m tt c cc nt u xa hn: trong trng hp ny s c mt l

hng.GEAR chn hop tip theo m lm ti thiu gi chi ph ca nt ln cn

ny. Trong trng hp ny, mt trong s cc nt ln cn c chn

chuyn tip gi da trn learned cost. La chn ny c th c cp nht

sau theo s hi t ca learned cost trong sut qu trnh truyn gi.

Chuyn tip gi trong vng: Nu gi c chuyn n vng, n c th truyn

d liu trong vng bng cch chuyn tip a l quy nhng mng c

mt sensor cao, ngi ta chia thnh 4 vng nh v to ra 4 bn copy ca

gi . Qu trnh chuyn tip v chia nh ny c tip tc cho n khi trong

vng ch cn 1 node. tha mn cc iu kin chng ta dng gii thut chuyn tip a l qui

truyn gi trong vng ny. Tuy nhin, vi nhng vng mt thp, chuyn tip

a l quy i khi khng hon thnh, nh tuyn v tc dng trong mt vng ch

rng trc khi s hop gi i qua vt qu gii hn.



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Hnh 2.13.Chuyn tip a l quy trong GEAR

CHNG 3: SO SNH HAI GIAO THC NH TUYN PHN

CP LEACH V PEGASIS

3.1 Kin trc giao thc LEACHVn m mng WSN phi i mt l gii hn v mt nng lng. thy

c cc vn trong mng WSN th chng ta pht trin giao thc LEACH (Low

Energy Adaptive Clustering Hierarchy). LEACH l giao thc phn cp theo cm

thch ng nng lng thp. N da trn thut ton phn nhm v c nhng c trng

sau :

Cc node c th phn b ngu nhin v t hnh thnh cm. Nt ch cm s iu

khin cc nt gi d liu n n trong cm. Qu trnh x l d liu l nt ch cm

s tng hp d liu t cc nt gi n ri gi ti trm c s BS ( Base station)



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Hnh 3.1.Giao thc LEACH

D liu ca cc node gi v c mi tng quan vi nhau trong mng WSN,

ngi dng cui khng cn yu cu tt c d liu (cc d liu c th ging nhau -

Redundant), hay ngi dng cui ch cn cc thng tin mc cao ca d liu m m

t v cc s kin xut hin trong mi trng m node cm bin c. V cc tn hiu

d liu c gi t cc nt t gn nhau c s tng quan rt ln, do chng ta

chn s dng kin trc phn nhm cho LEACH. iu ny cho php tt c d liu t

cc node trong phm vi cm s c x l cc b, gim c lng d liu truyn

ti ngi dng cui. Do m tit kim c nng lng ca node.

Trong giao thc LEACH, cc node t t chc thnh cc cm, trong mt

node s ng vai tr l node ch cm. Tt c cc node khng phi l nt ch s phi

truyn d liu ca n ti node ch, node ch cm phi nhn d liu t tt c cc nodethnh vin trong cm, thc hin x l d liu cc b (tng hp d liu-aggregation),

ri truyn ti BS (Basic Station). Bi vy, vic tr thnh node ch s tiu hao n

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