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Nng lng hiu qu thch ng a ng nh tuyn cho Wireless Sensor Networks
R Vidhyapriya, Tin s PT Vanathi Routing Abstract- trong cc mng cm
bin khng dy l mt yu cu nhim v. Nhu cu ny dn n mt s giao thc nh tuyn
m hiu qu s dng cc hn ch ngun lc sn c ti cc nt cm bin. Tt c cc giao
thc thng tm con ng nng lng ti thiu. Trong ny giy chng ta c mt ci
nhn , lun lun s dng ti thiu con ng nng lng tn tht cho nng lng mt
cch nhanh chng v cc nt thi gian thc hin xc nh mt con ng thay th tng
ln. n nh tuyn a ng phn phi lu lng gia cc nhiu ng thay v nh tuyn tt
c cc lu lng truy cp cng mt con ng duy nht. Hai cu hi quan trng pht
sinh trong a nh tuyn l bao nhiu con ng l cn thit v lm th no la chn
cc ng dn. R rng, s lng v cht lng ca cc ng dn chn sai khin hiu sut
ca mt a chng trnh nh tuyn. Chng ti xut mt thch ng nng lng hiu qu a
k thut nh tuyn trong s dng nhiu ng gia ngun v tn, thch nghi bi v h
c overhead nh tuyn thp. Giao thc ny c thit k cung cp mt mi trng
truyn dn tin cy vi thp tiu th nng lng, bng cch s dng hiu qu nng lng
sn c v cng tn hiu nhn c ca cc nt xc nh nhiu tuyn ng n ch. M phng Kt
qu cho thy rng nng lng hiu qu a adaptive chng trnh nh tuyn t c hiu
sut cao hn nhiu so vi cc giao thc nh tuyn c in, ngay c trong s hin
din ca mt cao v vt qua nt ng thi gi chuyn tip T kha : nng lng hiu
qu, a ng nh tuyn, nh tuyn, mng cm bin, I. GII THIU Mt mng cm bin
khng dy bao gm trng lng nh, thp in, kch thc nh cc nt cm bin. Cc lnh
vc ng dng cc cm bin khc nhau t cc mng qun s, dn s, y t, v mi trng
cho thng mi. V d v cc ng dng bao gm pht hin chy rng, hng tn kho iu
khin, nng lng qun l, gim st v trinh st, v nh vy [1] [2] [3]. Do chi
ph thp cc nt ny, vic trin khai c th c theo th t ln ngn n triu nt.
Cc nt c th c trin khai 1 hoc trong thi trang ngu nhin hay mt cch
tin ch. Cc cc nt cm bin thc hin cc php o nh mong mun, qu trnh Bn
tho nhn c ngy 29 thng 11 nm 2006. R. Vidhyapriya l vi PSG i hc Cng
ngh, S Cng ngh thng tin, Coimbatore - 641 004, Tamilnadu, n (in
thoi: 091-0422-2572177, e-mail: [email protected]) PT
Vanathi l vi PSG i hc Cng ngh, S in t v K thut Truyn thng,
Coimbatore - 641 004, Tamilnadu, n (in thoi: 091-0422-2572177,
e-mail: [email protected]) o d liu v chuyn n ti mt trm gc,
thng gi l cc nt chm, trn mt knh khng dy. Cc trm thu thp d liu t tt
c cc nt, v phn tch d liu ny rt ra kt lun v cc hot ng trong khu vc
ny quan tm [4]. Chu ra cng c th hnh ng nh l cc cng vo khc mng, mt b
x l d liu hoc cc im truy cp mnh m cho Giao din ca con ngi. Chng
thng c s dng ph bin kim sot thng tin hoc trch xut d liu t mng. Cc
vn chnh nh hn ch nng lng nghim ngt v d b tn thng ca cc b cm bin ng
mi trng iu kin, vn cn c gii quyt. H to ra mt nhu cu v nng lng hiu
qu v thit k giao thc mnh m c xem xt c th cc tnh nng c o ca mng cm
bin, chng hn nh trung tm d liu v t tn gii quyt cc quy c, mt cao v
mng li in hn ch. Gn y, cc giao thc nh tuyn khc nhau c xut cho WSNs.
Hu ht trong s h s dng mt con ng duy nht truyn d liu. Cc con ng ti u
c la chn da trn cc s liu, chng hn nh chnh lch ca thng tin, khong
cch n ch, hoc cc mc nng lng cn li nt. Mt s giao thc nh tuyn khc m s
dng nhiu ng la chn tin cy mng l u tin thit k ca h. a ng nh tuyn c s
dng trong vn hc m t lp hc ca cc c ch nh tuyn cho php nhiu ng c thit
lp gia ngun v ch. C in a ng nh tuyn c kho st cho hai l do. u tin l
Load Balancing: giao thng gia ngun v ch c chia trn nhiu (mt phn hoc
y ) ng dn. Vic s dng th hai ca nh tuyn a ng l tng kh nng cung cp d
liu ng tin cy. Trong nhng phng php tip cn nhiu bn sao ca d liu c gi
cng con ng khc nhau cho php kh nng phc hi n tht bi ca mt s lng nht
nh cc con ng. Nhiu con ng nh tuyn c nghin cu rng ri v c s dng trong
tt c cc loi hin c mng truyn thng nh Internet, tc cao mng v cc mng
ATM da trn QoS yu cu cn thit. Trong cc mng hng kt ni, t phng ti
nguyn phi c thc hin trc khi d liu c th c gi cng mt tuyn ng. i vi cc
kt ni ngn hoc bng pht, mt tuyn ng c la chn phi c cc ngun lc cn thit
m bo truyn thng ph hp vi mong mun lin quan n cht lng dch v (QoS). V
d, trong cc mng ATM, qu trnh thit lp tuyn ng ch xem xt lin kt vi ti
nguyn v tr cc ngun ti nguyn trong khi n tin v pha ch. Cc mi quan tm
tng t cho nh tuyn QoS xut hin trong cc mng gi nh Internet, khi cc
ng dng vi cc yu cu QoS cn dnh ti nguyn theo tuyn ghim cht. Cc a ng
cc thut ton thc hin t phng tng n ng thut ton t phng, hoc l lin tc
hay khng, thi gian kt ni thnh lp t phng a ng l thp hn ng k. V vy,
phng a ng IAENG quc t Tp ch Khoa hc my tnh, 34: 1, IJCS_34_1_8
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(Advance n phm trc tuyn: ngy 15 thng 8 nm 2007)
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tr thnh mt la chn hp dn cho cc tng tc cc ng dng nh World Wide
Web duyt. Vi c in ngn nht chng trnh con ng nh tuyn mt vi nt nm trn
rt nhiu cc ng i ngn nht ang cn kit ca h nng lng vi tc nhanh hn nhiu
so vi cc nt khc. L mt Kt qu ca nhng vi nt cht, cc nt trong ca n khu
ph c th tr nn khng th tip cn, m ln lt gy ra mt hiu ng gn sng v ton
b mng li tr thnh phn vng v khng th hot ng. Trong nhiu con ng nh
tuyn mi ngun pht hin ra v duy tr mt tp hp cc tuyn ng m c th s dng t
c im n ca mnh; cc tuyn ng c th c th c pht hin bng cch p dng mt thut
ton nh tuyn ngun. Chng ti khm ph vic s dng nhiu con ng nh tuyn cung
cp cho ti cn bng nn thi gian ca mng cm bin c th c ko di bng cch
truyn b thng qua mt s lng ln hn ca cc nt. Cn bng ti l c bit hu ch
trong nng lng mng hn ch v cc mc nng lng tng i ca cc nt khng nh hng
n tui th mng ca h hn mc nng lng tuyt i. Trong giao thc nh tuyn c
xut ca chng ti chng ti chia lu lng qua cc nt nm trn con ng c th khc
nhau gia ngun v tn, theo t l cn li ca h nng lng v cng tn hiu nhn c.
L do ng sau giao thng lan rng l mt tng nng lng c tiu th trong mng,
ti mi thi im, mi nt nn dnh cng mt lng nng lng. Cc Mc tiu l ch nh
nhiu ti trng con ng c khai thc v t ti ng qua cam kt thng nht s dng
ngun lc ca tt c cc ng dn c sn c th c m bo. a ng nh tuyn c chi ph
hiu qu cho ti nng kch bn, trong khi mt con ng duy nht vi mt chng
trnh nh tuyn thp phc tp nu khng c th nhiu hn mong mun . Chng ti so
snh k hoch xut ca chng ti vi s khuch tn o [5] v kt qu m phng giao
thc l lt cho thy nng lng hiu qu thch ng a ng nh tuyn tt hn nh tuyn
truyn thng cch tip cn v mng i, cn bng ti v t l phn phi gi d. Cc Phn
cn li ca bi bo c t chc nh sau. Phn II cung cp mt tng quan v cc cng
vic lin quan. Phn III gii thch cc hot ng nng lng thch ng hiu qu a
ng nh tuyn. Phn IV cung cp hiu nng nh gi cc chng trnh ca chng ti
cng nh s so snh vi cc giao thc khc. Phn V cung cp cc kt lun ca lm
vic v tho lun v nh hng tng lai . II. VIC LIN QUAN Mng cm bin gii
thiu nhng thch thc mi m cn phi c x l nh mt kt qu ca cc c tnh c bit
ca h. Ca h yu cu mi cn cc gii php ti u ha tt c cc lp ca ngn xp giao
thc trong mt n lc ti u ha vic s dng ngun lc khan him ca h [6] [7].
c bit, vic nh tuyn vn , nhn c rt nhiu s quan tm t cc cng ng nghin
cu vi mt s lng ln cc xut ang c thc hin. Cc giao thc c xut s dng
nhiu ng dn [9] [10] [11] chn tin cy ca mng nh h u tin thit k. Cc tc
gi trong [12] xut thut ton m s d liu thng qua cc tuyn ng mt con ng
m cc nt c nng lng d ln nht. ng dn l thay i bt c khi no mt con ng tt
hn c pht hin. Cc con ng chnh s c s dng cho n khi nng lng ca n gim
xung di nng lng ca ng dn sao lu sau cc ng dn sao lu l s dng. S dng
phng php ny, cc nt trong ng dn chnh s khng lm cn kit ngun ti nguyn
nng lng ca h thng qua lin tc s dng ca cng mt tuyn ng, do t c cuc
sng lu hn. Tuy nhin, con ng chi ph chuyn i l hn. Cc tc gi ca [9]
ngh s dng mt tp hp cc ng dn ph ti u i khi tng tui th ca mng. Nhng
con ng c la chn bng phng tin ca mt xc sut m ph thuc vo lng tiu th
nng lng ca mi con ng l. Cc con ng vi nhng nng lng cn li ln nht khi
c s dng d liu tuyn ng trong mng c th rt tn km v nng lng qu. V vy, c
mt s cn bng gia vic gim thiu tng s in nng tiu th v nng lng cn li ca
mng. Cc tc gi trong [13] xut mt thut ton trong cc nng lng cn li ca
tuyn ng c ni lng mt cht chn mt con ng nng lng hiu qu hn. Trong
[14], multipath nh tuyn c s dng nng cao tin cy ca WSNs. Cc n xut l
hu ch cung cp cc d liu trong mi trng khng ng tin cy. N c bit n mng
tin cy c th c tng ln bng cch cung cp mt s con ng t ngun n ch v bng
cch gi cng gi tin trn mi con ng. Tuy nhin, s dng k thut ny, giao
thng s tng ng k. Do , c mt s cn bng gia s lng lu lng v tin cy ca
mng. S cn bng ny c nghin cu trong [15] s dng mt chc nng d tha m l
ph thuc vo a mc v trn khng xc sut ca cc ng dn c sn. tng l phn chia
cc gi d liu ban u vo ph cc gi d liu v sau gi cho mi sub-gi d liu
qua mt trong nhng multipaths sn. N c tm thy rng ngay c khi mt s cc
tiu gi d liu b mt, thng bo ban u c th vn c ti to. Theo thut ton ca
h, n c cng c tm thy rng i vi mt li nt ti a cho xc sut, s dng mc a
cao hn so vi mt s gi tr ti u ny s nng tng xc sut ca s tht bi. o
khuch tn [5] l mt ng c vin tt cho mnh m a ng nh tuyn v giao hng. Da
trn ch o m hnh khuch tn, mt chng trnh nh tuyn a ng m tm thy mt s
con ng mt phn tch ri nhau c nghin cu trong [11] (thay th tuyn ng
khng c node ri nhau, v d cc ng l mt phn chng cho). N c tm thy rng
vic s dng ca a nh tuyn cung cp cc gii php thay th cho nng lng hiu
qu phc hi t tht bi trong WSN. Cc ng lc ca vic s dng cc ng dn bn l
gi cho chi ph ca vic duy tr multipaths thp. Cc chi ph ca ng thay th
l so snh vi cc con ng chnh v h c xu hng gn gi hn vi con ng chnh.
Trong [16] v [17], cc phn m rng a Dynamic Source Routing (DSR) v Ad
hoc On-demand Distance Vector (AODV) c xut nng cao hiu qu nng lng
cc mng qung co hoc bng cch gim tn s ca ng khm ph. Truyn o [18] l mt
trong nhng k thut nh tuyn theo xc sut, trong c ngun gc t l lt. N s
dng mt chc nng truyn li xc sut gim bt bn sao d phng d liu cng mt s
kin. Cc hop khong cch n ch v s lng cc bc m cc gi d liu i c s dng nh
cc tham s. Cc c ch kim sot pht li trnh c s thm s dng con ng ngn nht
trong mt mc nht nh. Cc kh c nh tuyn nhn thc c xut trong [9]. N s
dng cc b ngp cc thng ip yu cu tm tt c cc tuyn ng c th gia cc ngun v
bn ra, cng nh cc chi ph nng lng lin quan n cc ng dn. Trong bng nh
tuyn ca nt cm bin, mi xm c lin kt vi mt IAENG quc t Tp ch Khoa hc
my tnh, 34: 1, IJCS_34_1_8
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(Advance n phm trc tuyn: ngy 15 thng 8 nm 2007)
Trang 3
xc sut truyn ti, m c tnh ton da trn chi ph ca con ng i qua n. Cc
chng trnh duy tr nhiu ng nhng ch mt trong s h s dng ti mt thi im,
trong trnh nhn mnh mt con ng c bit v m rng i mng. Trong [12], cc a
tuyn l xy dng l mt vn lp trnh tuyn tnh vi mt Mc tiu ti a ha thi
gian cho n khi nt cm bin u tin chy ra khi nng lng. Cc ngun c gi nh
l truyn gi d liu tc khng i. Trong [19], a ng nh tuyn c xy dng l mt
hn ch ti u ha vn bng cch s dng mng xc nh tnh ton. Vic truyn d liu
da ch yu vo ng ti u. Cc con ng thay th duy nht khi c s dng cc nt
trn cc tuyn ng chnh tht bi. Mc d hin ti cch tip cn n ng l linh hot,
n gin v kh nng m rng, nt c th lm cn kit ngun cung cp nng lng ca h
vi tc nhanh hn. iu ny c th dn n phn vng mng sm. III. a ROUTING N Cc
nt cm bin c phn phi ngu nhin trong cc cm bin lnh vc. Mt mng li gm
mt nt chm v nhiu cc nt cm bin khng dy trong mt khu vc c coi l th v.
Gi nh rng tt c cc nt trong mng c gn vi mt ID duy nht v tt c cc nt c
tham gia trong mng v chuyn tip d liu nht nh. Cc nt cm bin l gi nh l
c nh cho cuc i ca mnh, v nhn dng ca cc nt cm bin c xc nh trc. Ngoi
ra, cc nt cm bin hn ch sc mnh x l, lu tr v nng lng, trong khi cc nt
chm c mnh m ngun lc thc hin bt k cng vic hay giao tip vi cc cc nt
cm bin. Mt khi cc nt c trin khai, h vn ti cc a im lm nhim v cm bin.
Cc nt cm bin c th nhn tin nhn t cc nt khc. Cc nt chm l khi to vi mt
gi tr hop "0", trong khi cc nt cm bin khc l "". Nng lng hiu qu thch
ng a ng nh tuyn thut ton xut c s dng la chn cc lng ging nt, m cc
thng ip d liu c c chuyn tip. Mt nt c chn chuyn tip d liu da trn sn
c ca mnh mc nng lng v cng tn hiu. L tng nht, ln hn nng lng trong nt
v xa hn vo nt t trc mt, l nhiu kh nng c chn l bc k tip. Cc cc nt m
khng c chn trong qu trnh ny s chuyn n cc trng thi ng tit kim in. Cc
thng tin lin lc c gi nh l hai chiu v i xng. Cc giao thc tr li vi
nhiu tuyn ng t nt ngun bn ra nhanh chng, v chun b cc ng i c hiu qu
cn bng nng lng ca cc nt. N cng cho php cc nt chn trong cc ng dn n
tp hp tt c cc gi d liu nhn c trong mt khong thi gian ngn v ch truyn
cc gi d liu tng hp cc nt pha thng lu. Mi nt duy tr mt bng nh tuyn
cho hng xm giao thc hot ng. Bng xm cha mt mc nhp ca tt c cc nt ln
cn la chn thng qua mt nt c th truyn ti d liu. A. Multipath Routing
Cc a ng nh tuyn m hnh mng cm bin vo cp theo khong cch hop t nt chm
mt nt ngun. Mt nt l mc L, nu n l L nhy ngoi t bn ra chn. Chic bn ra
l mt nt mc 0. Tt c cc nt c th ni chuyn trc tip vi t nht mt nt cp N
nhng khng th ni chuyn trc tip vi bt k cp N-1 nt c nh ngha l mc N +
1 nt. Nh vy, cc nt mc N c chiu di ng i ca N nhy tr li vo bn. Cc
thut ton nh tuyn a ng l bao gm hai giai on: Giai on xy dng
Multipath v giai on truyn d liu bng cch s dng hai thng ip c th l yu
cu tuyn ng v tuyn ng nhn tin nhn tr li. Route Request tin nhn c
truyn khi mt nt vo trong mng thc hin qu trnh khm ph hng xm trong qu
trnh khi mng v cn thit lp mt l trnh ch v Route Reply tin nhn c khi
xng khi nt ngun c a ra l t v to ra mt mc mi trong bng lng ging a
phng. B. Giai on xy dng Multipath Cc nt tn bt u giai on xy dng con
ng a to ra mt tp hp ca hng xm m l a ch ca tt c cc nt m c th truyn d
liu t cc ngun. Trong thi gian ny thng ip yu cu tuyn ng qu trnh trao
i gia cc nt. Mi nt cm bin pht sng yu cu ng gi mt ln v duy tr bng nh
tuyn ca n. Khi no nt cm bin ph bin mt gi d liu, n ch cn bit nt lng
ging ca mnh chuyn, khng cn phi duy tr cc thng tin ton b con ng. K t
khi con ng c hnh thnh bt c khi no n c yu cu khng ging nh nh tuyn ch
ng giao thc m n l cn thit lu tr cc nh tuyn thng tin, n lm gim chi
ph ca cc nt cm bin. Mc d cc giao thc nh tuyn a ng c tnh ton mt s
thng tin ghi li trong bng nh tuyn ca cm bin nt, chi ph nng lng thp
hn v pht tn hiu nhn c. Hn na, n h tr d liu a chuyn tip, khng s dng
cc con ng c nh. V vy, nng lng tiu th s c phn phi v tui th ca mng l
ko di. nh dng ca tuyn ng thng ip yu cu c th hin trong hnh. 1. ID
Source cha cc nt ID ca tin nhn ni n; trng SeqNumber l mt th t gi.
Cc Lnh vc HopCount l s hop t nt chm c s dng xc nh cc nt mc khc
nhau, cc nt c th nhn c tn hiu radio ca bn ra c nh ngha l one-hop /
cp 1 nt, E lnh vc ngng nergy cung cp mc nng lng ti thiu cn thit cho
mt nt c chn truyn ti d liu, ngng Signal Strength ch ra khong cch ti
thiu cc node c c nm trong trt t nhn c tt c cc d liu ca truyn ti m
nt v chm ID cho bit ID ca bn ra m chng trnh pht sng cc gi yu cu ng.
Ngun ID SeqNumber HopCount Nng lng Threshold Chm ID SignalStrength
Threshold Hnh 1: ng Yu cu nh dng khung tin nhn Cc hot ng ch yu
trong giai on ny c nh tuyn ng hnh thnh cho mi nt v tha nhn to bng.
Cc nt tn pht sng cc gi yu cu ng khm ph cc nt mt hop / cp 1 nt, cc
nt l nhn h u tin. Yu cu thng Route c s dng xc nh cc nt mc khc nhau.
Sau khi yu cu ng tin nhn c gi bng nt chm, cc h s m hop bao nhiu bc
nhy i t bn ra chn. S m hop trng l mt tng mi ln khi mt nt nhn c thng
bo yu cu ng. Khi nhn c mt tuyn ng yu cu, mt nt t coi mnh cp N nu s
lng hop IAENG quc t Tp ch Khoa hc my tnh, 34: 1, IJCS_34_1_8
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(Advance n phm trc tuyn: ngy 15 thng 8 nm 2007)
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l N. Nu mt s nh hn hop (ni, N-1) c nhn sau t mt yu cu l tuyn ng
c s th t ging nhau, nh dng nh, cc nt cp nht mc ca n theo hop count
mi. Nt hop count nh thng xuyn s dng t nng lng hn so vi nhng ngi
khc. Bt u Node nhn c Route Request Gi Increment Dng HopCount Lnh vc
HopCount < gi tr hop nt ca Hy gi Gi Process Hch nng lng <
ngng nng lng Hy gi Nt RSS 700 s Topology Kch 1000m x 1000m S cm bin
100 S chm 1 Loi hnh giao thng Tc bit khng i Tc gi 5 gi / s Kch thc
gi 512 byte Phm vi pht thanh 350m Lp MAC IEEE 802.11 Bng thng 2Mb /
s Truyn ti in nng 660mW Nhn in 395mW in nng nhn ri 35mW Node
Placement ng dng Nng lng ban u trong cc loi pin 10 Joules Signal
Strength Threshold -80 DBm Ngng nng lng 0.001mJ nh gi cc giao thc
sau ba cc s liu c la chn. Mi s liu c nh gi l mt hm ca kch thc topo,
s nt trin khai, v vic ti d liu ca mng. B. Hiu sut Metrics Tiu th
nng lng Node ( mt E ): Cc nt nng lng tiu th nng lng trung bnh cc
bin php tiu tan bint truyn mt gi d liu t ngun n bn ra chn. Cc s liu
tng t c s dng trong [5] xc nh mc hiu qu nng lng ca WSNs. N l tnh nh
sau: ( ) 1 1 , , M ti S j i init i res mt M j e e E dataN = = = -
ni M l s nt, e i, init v e i, res l tng ng cc mc nng lng ban u v cn
li ca nt i , S l s lng cc nt chm v dataN j l s cc gi d liu nhn c bi
sink j .T l giao hng d liu (R): S liu ny cho t lgia s lng cc gi d
liu c gi bi cc ngun v s lng cc gi d liu c nhn bn ra. Chuyn thnh cng
d liu T l giao hng d liu = ---------------------------------- D liu
cn thit S liu ny cho thy c hai t l tn tht ca nh tuyn giao thc v n
lc cn thit nhn d liu. Trong kch bn l tng t l phi bng 1. Nu t l ny
gim ng k di mc t l l tng, sau n c th l mt du hiu cho thy mt s li
trong thit k giao thc. Tuy nhin, nu t l ny l cao hn so vi t l l
tng, sau n l mt du hiu cho thy b tn nhn c mt gi d liu hn hn mt ln.
N khng phi l mong mun v nhn cc gi d liu trng lp tiu th ca mng c gi
tr ngun lc. S tng i ca cc bn sao nhn c bn ra cng rt quan trng bi v
da trn con s IAENG quc t Tp ch Khoa hc my tnh, 34: 1, IJCS_34_1_8
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(Advance n phm trc tuyn: ngy 15 thng 8 nm 2007)
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bn ra, c th c th c mt hnh ng thch hp gim d phng S chm tr trung
bnh: N c nh ngha l thi gian trung bnh gialc ny mt gi d liu c gi bi
mt ngun d liu v cc lc ny tn nhn cc gi d liu. S liu ny xc nh s ti mt
ca cc gi d liu. C. Kt qu m phng Di ch nng lng, n l rt quan trng cho
cc nt cm bin gim thiu tiu th nng lng trong thng tin v tuyn. T kt qu
th hin trong hnh 5, ta quan st thy rng c l mt tiu th nng lng thp ca
nt thch nghi ca chng ti a ng nh tuyn trn cc chng trnh khc. L lt l
cc giao thc tn km nht v s lng hoa bia c xu hng tng khi mt nt tng.
Cc khuch tn o c c ci thin hn na. Hnh 5 cho thy mt s gia tng nng lng
tuyn tnh nh mng tr nn dy c hn, nh cc nt cm bin nhiu hn tham gia vi
cho c hai khuch tn o v thut ton a. 0 0.02 0.04 0.06 0.08 0.1 50 100
150 200 250 300 S Nodes L lt Diffusion o Multipath Routing Hnh 5:
Node trung bnh tiu th nng lng L do m mc tiu th nng lng ca o din
thut ton khuch tn tng nhanh hn so vi a thut ton nh tuyn l v s lng
cm bin tham gia khm ph tuyn l t. Cc ci thin a ng nh tuyn khc nhau,
t 10% n 30% khi so vi khuch tn o. Nh vy Kt qu thc nghim chng minh
rng nng lng hiu qu ca a tuyn l n nh v c t tc ng ca vic tng kch thc
mng, trong khi thc hin cc n khc gim vi ln hn kch thc mng. Hnh 5 cho
thy t l giao hng ca tt c ba tuyngiao thc. loi b cc gi tin b mt,
chng ti s dng mt t l 5 cc gi tin / giy. N c tm thy rng t l giao hng
ca tt c cc cc giao thc tng khi tng mt node. Khi mt nt l cao, c cc
nt hn c sn chuyn tip d liu, v iu ny lm tng t l giao hng. L lt cung
cp t gi giao gi, theo sau l lt l o khuch tn; n khng thch ng cng hnh
vi ca n vo mng quy m tng. Nng lng giao thc nh tuyn a hiu qu c duy
tr T l sinh lin tc trong sut kch bn m phng v ng c la chn da trn nng
lng sn c. 0 0.2 0,4 0.6 0.8 1 50 100 150 200 250 300 S Nodes De l
ti v e r y Ra t ti o L lt Diffusion o Multipath Routing Hnh 6: T l
giao hng y l mt kt qu ca s tc ng ca qu trnh s dng n to ra mt con ng
nh tuyn. Di ch nng lng, n l rt quan trng cho cc nt cm bin gim thiu
tiu th nng lng trong thng tin lin lc v tuyn ko di tui th ca cc cm
bin mng. T kt qu th hin trong hnh 6, chng ta suy ra rng nng lng a
hiu qu nh tuyn c xu hng gim s lng hoa bia trong cc tuyn ng, do lm
gim nng lng tiu th truyn. Hnh 7 th hin s cn bng ti kh nngba chng
trnh nh tuyn. D liu chuyn trung bnh l o l s trung bnh ca cc s kin
chuyn tip d liu bi mt giao d liu cho tt c cc s kin ring bit gi n bn
0 1 2 3 4 50 100 150 200 250 300 S Nodes Mt v g . N o . o f fo r w
mt r d e d d mt ta / N o d e L lt Diffusion o Multipath Routing Hnh
7: Load Balancing Capability S liu ny phn nh hiu qu nng lng di hn v
tim nng kh nng chu li mng. Nh th hin trong hnh 7, kh nng cn bng ti
ca a tuyn tng hai ln so vi cc giao thc nh tuyn khc trong hu ht cc
mt kch bn. Chng ti cng nghin cu cc end-to-end chm tr thc hin ccgiao
thc nh tuyn. C hai tuyn ng sn c s chm tr v tuyn truyn chm tr ca cc
gi d liu ng gp vo cc d liu tr. S chm tr gi tin trung bnh di ba n c
v trn hnh 8. chm tr khc l khng c nhiu hn khong 1,3 giy cho 250m phm
vi truyn dn. S chm tr thm ny pht trin chm vi s gia tng dn s nt. Nhn
chung, cc Kt qu cho thy nng lng hiu qu a giao thc nh tuyn ca kh nng
duy tr hiu sut ng dng ngay c i ln mt node. Nhiu n lc khc tit kim
nng lng cho thy hiu sut phn phi gi d thng gim l kt qu tit kim nng
lng tng. Ca chng ti Kt qu cho thy rng thut ton nng lng hiu qu c th
lm gim IAENG quc t Tp ch Khoa hc my tnh, 34: 1, IJCS_34_1_8
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(Advance n phm trc tuyn: ngy 15 thng 8 nm 2007)
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cc chi ph nng lng ca truyn thng vi mc ti thiu cn bng cht lng dch
v. i vi tt c cc iu kin giao thng a ng nh tuyn trin lm t hn hai phn
ba cc d liu tr ca l lt, iu ny l do thc t rng cc tuyn ng la chn c
nhiu ti u ha bng cch chn ngn nht multipaths chng li nhng con ng di
hn. 0 0.5 1 1.5 2 2.5 3 3.5 50 100 150 200 250 300 S Nodes D el mt
y ( se c) L lt Diffusion o Multipath Routing Hnh 8: Trung bnh gi
tin d liu giao hng chm tr V. KT LUN Hn ch ti nguyn nng lng l mi
quan tm u tin trong mng cm bin. Phn phi ti cho nt tc ng ng k tui th
ca h thng. Cc adaptive giao thc nh tuyn a ng c kh nng tm kim nhiu
con ng v mc tiu phn b t l lu lng truy cp n tng con ng ti u. Kt qu m
phng cho thy rng chng ti xut n c hiu qu nng lng cao hn nt, hn khuch
tn o, v l lt. Cc gii hn trong ca chng ti Chng trnh ny l cc gi tr
RSSI c s dng, khng phi l khng i trong sut thi gian m phng, hn na
fading v nhiu gy ra bi mi trng khng dy khng c a vo xem xt iu ny t
ra mt gii hn v xc nh hiu sut mng trong th gii thc kch bn. C mt s
cng trnh trong tng lai chng ti mun tp trung vo. u tin, lm th no m
bo vic cung cp cc gi tin di tnh hung m cc phm vi truyn dn khng ng
nht tn ti. Th hai ci thin cc thut ton bao gm cc tch hp cc tp hp d
liu v cui cng s h tr ca nt vi tnh di ng hn ch. Mt gii php ti u ny
Vn c bit cho cc mng cm bin in thoi di ng vn cn mt l cu hi m. THAM
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tnh, 34: 1, IJCS_34_1_8
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34: 1, IJCS_34_1_8
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(Advance n phm trc tuyn: ngy 15 thng 8 nm 2007)
Vn bn Ting Anh gc:multipath routing and delivery.ng gp bn dch
hay hn