Bai Giang Mang Cam Bien

7/30/2019 Bai Giang Mang Cam Bien

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C LC

MC LC ...............................................................................................................1

Chng 1. TNG QUAN V MNG CM BIN KHNG DY .........................4

1.1. Khi nim v mng cm bin khng dy........................................................41.2. Nhng thch thc i vi mng cm bin khng dy.....................................5

1.2.1. Nhng thch thc cp nt................................................................5

1.2.2. Nhng thch thc cp mng ............................................................6

1.2.3. S chun ha...........................................................................................8

1.2.4. Kh nng cng tc...................................................................................9

1.3. Kin trc ngn xp giao thc ca mng cm bin khng dy .......................10

1.3.1. Lp vt l..............................................................................................11

1.3.2. Lp lin kt d liu ...............................................................................11

1.3.3. Lp mng..............................................................................................12

1.3.4. Lp giao vn .........................................................................................13

1.3.5. Lp ng dng........................................................................................14

1.4. Chun truyn thng IEEE 802.15.4 cho mng cm bin khng dy .............15

1.4.1. M hnh truyn thng trong mng cm bin khng dy.........................15

1.4.2. Chun truyn thng vt l cho mng cm bin khng dy .....................18

Chng 2. PHN CNG CHO MNG CM BIN KHNG DY.....................25

2.1. Cu trc phn cng ca nt cm bin khng dy..........................................25

2.1.1. Thit b truyn thng.............................................................................26

2.1.2. B vi u khin ................................................................ .................... 27

2.1.3. Cm bin...............................................................................................28

2.1.4. Ngun cung cp..................................................................................... 28

2.2. Kho st mt s nn tng phn cng ph bin cho mng cm bin khng dy

...........................................................................................................................29

2.3. Gii php thit k phn cng TUmote cho mng cm bin khng dy .........31

2.3.1. B vi u khin MSP430......................................................................31

2.3.2. B thu pht v tuyn CC2420................................................................32

2.3.3. Cm bin nhit , m......................................................................32

2.3.4. B nhngoi.........................................................................................32


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2.3.5. Kt ni mrng ....................................................................................32

2.3.6. Giao tip USB .......................................................................................32

2.3.7. Ngun cung cp..................................................................................... 32

2.4. Cng c phn mm u khin v thu thp d liu TU2C ............................33

2.5. Mt s hnh nh v phn cng TUmote v chng trnh phn mm TU2C..33

Chng 3. HU HNH CHO MNG CM BIN KHNG DY................ 36

3.1. Gii thiu v phn mm ca nt cm bin khng dy ..................................36

3.2. Hu hnh cho mng cm bin khng dy ...............................................36

3.3. Nhng thch thc nh hng n vic thit k hu hnh cho mng cm

bin khng dy ...................................................................................................37

3.4. Kho st mt s hu hnh cho mng cm bin khng dy ......................38

3.4.1. Hu hnh TinyOS............................................................................38

3.4.2. Hu hnh LiteOS.............................................................................39

3.4.3. Hu hnh Contiki.............................................................................40

3.5. Hu hnh Contiki cho mng cm bin khng dy...................................41

3.5.1. Gii thiu ..............................................................................................41

3.5.2. Cu trc hu hnh Contiki ...............................................................42

3.5.3. Ngn xp truyn thng trong hu hnh Contiki................................43

3.5.4. M hnh lp trnh trong hu hnh Contiki ........................................46

3.5.5. Cc bnh thi trong hu hnh Contiki..........................................493.5.6. Mt s hng dn cbn vi hu hnh Contiki...............................49

Chng 4. GIAO THC LP MAC TRONG MNG CM BIN KHNG DY55

3.1. Cch qun l nng lng lp MAC........................................................... 55

3.2. Cch qun l cng sut v tuyn...............................................................56

3.2.1. Chu k cng sut khng ng b...........................................................58

3.2.2. Chu k cng sut ng b .....................................................................62

Chng 5. NH TUYN TRONG MNG CM BIN KHNG DY ..............645.1. Tng quan v vn nh tuyn trong mng cm bin khng dy................64

5.2. Nhng thch thc ca vn nh tuyn trong mng cm bin khng dy...65

5.3. Kho st mt s giao thc nh tuyn trong mng cm bin khng dy........67

5.3.1. Cc giao thc nh tuyn trung tm d liu ...........................................67

5.3.2. Cc giao thc nh tuyn da trn s phn cm.....................................68


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5.3.3. Cc giao thc nh tuyn da trn v tr.................................................69

5.3.4. Giao thc cy thu thp d liu CTP.......................................................69

5.4. Giao thc cy thu thp d liu CTP .............................................................70

5.4.1. Gii thiu giao thc CTP.......................................................................70

5.4.2. Thc thi giao thc CTP trn hu hnh Contiki.................................72

Chng 6. MNG CM BIN KHNG DY TRN NN KIN TRC IP........79

6.1. Gii thiu v kin trc IP.............................................................................79

6.2. u im ca mng cm bin khng dy trn nn kin trc IP......................80

6.2.1. Kh nng cng tc.................................................................................80

6.2.2. Mt kin trc pht trin v linh hot......................................................82

6.2.3. Tnh n nh v s ph bin ca kin trc .............................................83

6.2.4. Kh nng mrng.................................................................................83

6.2.5. Cu hnh v qun l mng .....................................................................83

6.2.6. Kch thc nh gn...............................................................................84

6.3. S chun ha kin trc IP cho mng cm bin khng dy bi IETF.............85

6.3.1. Nhm lm vic 6LoWPAN ...................................................................86

6.3.2. Nhm lm vic RoLL............................................................................87

6.4. M hnh kt ni mng cm bin khng dy trn nn kin trc IP .................88

6.4.1. M hnh mng cm bin khng dy t tr ..............................................88

6.4.2. M hnh mng cm bin khng dy kt ni vi Internet ........................896.5. Cc giao thc lp truyn ti .........................................................................90

6.5.1. Giao thc UDP cho mng cm bin khng dy .....................................90

6.5.2. Giao thc TCP cho mng cm bin khng dy ......................................92

6.6. IPv6 cho mng cm bin khng dy.............................................................98

6.6.1. Gii thiu v IPv6 ................................................................................. 98

6.6.2. Tiu IPv6 cnh .............................................................................99

6.6.3. Kin trc a ch IPv6..........................................................................1006.7. Lp thch ng 6LoWPAN..........................................................................102

6.7.1. Phn mnh gi tin................................................................................105

6.7.2. Nn tiu 6LoWPAN .......................................................................106

TI LIU THAM KHO....................................................................................111


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Chng 1. TNG QUAN V MNG CM BIN KHNG DY

1.1. Khi nim v mng cm bin khng dy

Mng cm bin khng dy (Wireless Sensor Network) l mt kt cu h tng

bao gm cc thnh phn cm nhn (o lng), tnh ton v truyn thng nhm cungcp cho ngi qun tr kh nng o c, quan st v tc ng li vi cc s kin, hin

ng trong mt mi trng xc nh. Cc ng dng n hnh ca mng cm bin

khng dy bao gm thu thp d liu, theo di, gim st v y hc

Mt mng cm bin khng dy bao gm nhiu nt mng. Cc nt mng

thng l cc thit bn gin, nh gn, gi thnh thp, c s lng ln, thng

c phn b trn mt din tch rng, s dng ngun nng lng hn ch (thng

dng pin), c thi gian hot ng lu di (t vi thng n vi nm) v c th hot

ng trong mi trng khc nghit (nh trong mi trng c hi, nhim, nhit

cao,).

Cc nt cm bin thng nm ri rc trong trng cm bin nhc minh

ha hnh 1.1. Mi nt cm bin c kh nng thu thp v nh tuyn d liu n mt

Sink/Gateway v ngi dng cui. Cc nt giao tip vi nhau qua mng v tuyn ad-

hoc v truyn d liu v Sink bng k thut truyn a chng. Sink c th truyn

thng vi ngi dng cui/ngi qun l thng qua Internet hoc v tinh hay bt k

mng khng dy no (nh WiFi, mng di ng, WiMAX) hoc khng cn n cc

mng ny m Sink c th kt ni trc tip vi ngi dng cui. Lu rng, c

th c nhiu Sink/Gateway v nhiu ngi dng cui trong kin trc th hin hnh1.1.

Hnh 1.1: Mng cm bin khng dy vi cc nt cm binphn b ri rc trong trng cm bin.


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Trong cc mng cm bin khng dy, cc nt cm bin c c hai chc nng

l va khi to d liu v va l bnh tuyn d liu. Do vy, vic truyn thng

c thc thc hin bi hai chc nng l:

Chc nng ngun dliu: Cc nt thu thp thng tin v cc s kin v thc

hin truyn thng gi d liu ca chng n Sink.

Chc nng bnh tuyn: Cc nt cm bin cng tham gia vo vic chuyntip cc gi tin nhn c t cc nt khc ti cc m n k tip trong tuyn

ng a chng n Sink.

1.2. Nhng thch thc i vi mng cm bin khng dy

1.2.1. Nhng thch thc cp nt

Trong mng cm bin khng dy, nhng thch thc chnh cp nt cn

phi gii quyt l cng sut tiu th, kch thc vt l v gi thnh. Cng sut tiu

th l mt yu t quan trng i vi cc nt mng cm bin khng dy bi v chng

thng s dng ngun nng lng l pin hoc mt ngun ng lng thp bn ngoi.

Kch thc vt l cng rt quan trng bi v cc yu t kch thc v hnh thc quyt

nh n cc ng dng tim nng cho mng cm bin khng dy, cc nt mng cm

bin khng dy phi c kch thc nh gn. Gi thnh cng quan trng i vi cc

nt mng cm bin khng dy bi v mng cm bin khng dy thng c trin

khai vi quy m ln. Vi vic trin khai hng ngn cc nt mng cm bin th vic

tit kim gi thnh mt vi la cho mi nt s cho php tit kim c mt khon

tin ng k.

Hn ch nghim trng trong vn tiu th ng lng c nh hng nvic thit kphn cng, phn mm, giao thc mng v thm ch c kin trc mng.

i vi cc nh thit kphn cng, bt buc phi la chn cc linh kin phn cng

c cng sut thp v b tr gim thiu ti a dng r cng nh h trch ng

hiu qu v mt nng lng. Phn mm chy trn cc nt cm bin khng dy cn

phi tt cc thnh phn phn cng khng s dng v t cc thnh phn phn cng

ch ng cng nhiu cng tt. Nhs h trca cc nh pht trin phn mm, cc

nt mng cm bin c th chy hu hnh v n cung cp cc cch hot ng

cng sut thp gip tit kim nng lng.Vn hiu qu ng lng nh hng ng k n kin trc mng cng nh

vic thit k cc giao thc mng. Bi v qu trnh truyn thng tiu tn nhiu ng

ng nn iu quan trng l xc nh hng cc kiu truyn thng chng s dng

hiu qu ti nguyn sn c. gip cc giao thc mng lm c iu ny, phn

cng v phn mm cn bit c thng tin v s tiu hao ng lng v cung cp

thng tin ny n tng mng. Ngoi ra, tit kim nng lng, ngi thit k h


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thng cn phi t cc thit b phn cng ch ng cng nhiu cng tt. Tuy

nhin, ch ng cng nh hng n tr truyn thng ca h thng.

Kch thc vt l v gi thnh c nh hng ln i vi c nh thit kphn

cng ln phn mm. i vi cc nh thit kphn cng th nh hng y l cc

phn cng cn phi c kch thc nh gn, s lng cc linh kin cn phi t, mi

linh kin cn phi c kch thc nh v r tin. Nhng nh hng i vi cc nhthit kphn mm l t r r t n. Vi chi ph thp, kch thc vt l nh, cng sut

tiu th thp th cc b vi x l m trn cc phn mm hot ng trnn nh gn

n, tc tnh ton v kch thc b nhca cc b vi x l cng b gim bt. Cc

nh thit k phn mm cho mt h thng mng cm bin khng dy thng ch c

vi ngn Byte b nh lm vic s o vi hng triu hoc hng t Byte b nh trong

cc h thng my tnh thng dng. Do , phn mm cho cc nt mng cm bin

khng dy khng ch cn hiu qu nng lng m cn phi c kh nng chy trong

mt mi trng hn ch nghim ngt v ti nguyn.1.2.2. Nhng thch thc cp mng

Nhng thch thc cp nt ca mng cm bin khng dy cn gii quyt

l s hn ch v ngun ti nguyn sn c, trong khi nhng thch thc cp mng

cn gii quyt li l vn quy m ln ca mng cm bin khng dy.

Mng cm bin khng dy c tim nng rt ln c v quy m, s lng cc

nt tham gia vo h thng v cc d liu c to ra bi mi nt. Trong nhiu trng

hp, cc nt cm bin khng dy thu thp mt lng ln d liu t nhiu m thu

thp ring bit. Nhiu mng cm bin khng dy bao gm hng ngn cc nt cmbin.

Kch thc mng nh hng n vic thit k giao thc nh tuyn trong

mng cm bin khng dy. nh tuyn l qu trnh mng xc nh nhng tuyn

ng tt nht truyn bn tin qua mng. nh tuyn c thc thc hin hoc l

tp trung hoc l phn tn. Vi nh tuyn tp trung th mt my ch tnh ton bn

nh tuyn cho ton b mng, cn vi nh tuyn phn tn th mi nt thc hin t

quyt nh la chn tuyn ng gi mi bn tin.

Thit k cc giao thc nh tuyn l rt quan trng bi v n nh hng n c

hiu nng mng xt v lng d liu m mng c th duy tr cng nh tc d liu

c th vn chuyn d liu thnh cng qua mng v hn ht l khong thi gian

tn ti ca mng c m bo. Trong mng cm bin khng dy, vic truyn thng

tin i hi nng lng. Cc nt thc hin truyn thng tin nhiu s mt nng lng

nhanh hn so vi cc nt khc thng ch ng. V vy, giao thc nh tuyn

phi la chn y thng tin khi lp k hoch vn chuyn bn tin qua mng.


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i vi mt nt khi thc hin la chn thng tin nh tuyn th n yu cu cc

thng tin c v mng cng nh ton b cc nt ln cn gn nht. Thng tin ny i

hi cn phi c b nh. Tuy nhin, mi nt c mt s lng b nhhn ch. V vy,

giao thc nh tuyn phi la chn mt cch k lng gi li nhng thng tin v

mng, v cc nt ln cn cn thit v b qua nhng thng tin khng cn thit khc.

Cc mng cm bin khng dy thng hot ng trn knh truyn khng ngtin cy, u ny lm cho vn nh tuyn cng gp nhiu kh khn. Trong knh

truyn thng v tuyn cng sut thp th khng chc chn rng nu mt bn tin

c gi i bi mt nt th bn tin s nhn c bi mt nt ch c d kin

trc trong mng. Bn tin ny c th b gin n hoc c th b chn hon ton bi

mt vt ln bng kim loi va c t gia pha gi v pha nhn. Ngay c khi bn

tin khng b chn hon ton th cc bit ca n c th b thay i trn ng truyn.

Tnh cht khng ng tin cy ca mng cm bin khng dy c gi l "tn

hao". Tn hao nn c coi nh l mt c tnh vn c trong mng cm bin khngdy. Vn tn hao trong mng cm bin khng dy l mt thch thc i vi cc

giao thc nh tuyn. Cc giao thc nh tuyn phi tnh ton vn tn hao khi

quyt nh tuynng truyn cc bn tin v c th bn tin cn phi c gi li.

Cc bn tin sc nh tuyn sao cho cc nguy c mt mt bn tin l thp nht.

Nhng nu mt bn tin c truyn qua mt tuyn ng xy ra vic mt d liu th

bn tin cn c gi li mt vi ln trong trng hp bn tin khng th gi c qua

mng trong ln thu tin.

Tn hao l mt thuc tnh kh xc nh, c bit l trong cc mng khng

dy. Tn hao b nh hng bi cc yu t mi trng nh nhit v m ca

khng kh cng nh mi trng vt l xung quanh ca cc mng cm bin khng

dy. V d, nu mt l vi sng c bt ln, cc trng n t m n to ra c th

can thip vo bng tn truyn khng dy 2.4GHz. Tng t nh vy, mt mng my

tnh WiFi c thnh hng ti mt mng cm bin khng dy, do cc mng cm

bin khng dy thng b mt d liu nhiu hn vo ban ngy, khi m mi ngi

ang s dng mng WiFi hn l vo ban m. Cc giao thc nh tuyn cho mng

cm bin khng dy cn phi c chun b trc cho nhng vn ny.

Tnh cht quy m ln ca cc mng cm bin khng dy lm phc tp thmvic nh a ch cc nt. Trong mt mng quy m ln, mi nt phi c a ch ring

cc bn tin c thc gi ti n. Cc a ch cn c di ln sao cho mi

nt trong cc mng quy m ln phi c mt a ch ring bit. V ngay c khi mng

c quy m nh th n c th tng tc vi cc nt mng khc bn ngoi. Trong

trng hp ny, a ch ca cc nt trong hai mng phi l duy nht.


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V s lng cc mng cm bin khng dy c th tng tc vi cc mng

khc bn ngoi ngy tng, nn chng ta cn phi chun b cho quy m pht trin theo

cp s nhn. Do , cchnh a ch cho cc mng cm bin khng dy phi xc

nh duy nht vi triu, thm ch vi t cc nt mng ring bit.

Vic qun l mng i vi mng cm bin khng dy quy m ln l mt

thch thc v cng kh khn. Vi mng cm bin khng dy c th bao gm hngngn nt th vic thc hin qun l mng theo cch truyn thng khng th p dng

ngay c. Qun l theo cch truyn thng i hi su chnh csh tng mng

th cng bi mt qun tr vin h thng. Vi cc mng cm bin khng dy dng

Ad-hoc, mng phi c chun b t qun l chnh n m khng c bt k su

hnh mng no ca con ngi. Ngoi ra, trong mng my tnh truyn thng, mi my

tnh kt ni mng c th yu cu cu hnh th cng hoc bn th cng. V d nh

ngi dng cc my tnh c th cn phi nhp mt khu truy cp mng. i vi

mng cm bin khng dy th iu l khng kh thi khi cho mt ngi nhp mtkhu vo tng nt mng cm bin ti cc thi m khi cn truy cp mng.

Mt mng cm bin khng dy cng phi cung cp cc cch truy cp t bn

ngoi. C nhng trng hp m mt mng cm bin khng dy c s dng c lp,

nhng thng thng cc d liu to ra bi cc mng cm bin khng dy cn phi

c ly ra x l hoc c lu trmt ni khc. Ngoi ra, cc mng cm bin

khng dy cn phi c cu hnh li hoc thay i trong qu trnh hot ng. Trong

c hai trng hp, cc mng cm bin khng dy phi cho php truy cp c t bn

ngoi.

1.2.3. Schun ha

Tiu chun l mt yu t then cht i vi s thnh cng ca cc mng cm

bin khng dy. Mng cm bin khng dy c bit n khng ch bi s lng ln

cc nt v cc ng dng tim nng m cn c bit n vi vic c nhiu tiu

chun, nhiu nh sn xut v nhiu cng ty khc nhau cng quan tm ng gp v

mt cng ngh. Cc cng ngh sn xut khc nhau c nhng tiu chun khc nhau.

Mt nh sn xut thit b cm bin chuyn v cm bin m chnh xc cao c th

khng quan tm n cc h thng cng ngh thng tin. Tuy nhin, c hai phi lm

vic cng nhau trong h thng ta nh tng, cc cm bin m to ra u

vo cho vic kim sot mi trng trong to nh. H thng kim sot mi trng

c u khin bi mt h thng cng ngh thng tin tin tin, chng tip nhn u

vo t cc cm bin m.

Nu khng c s chun ha th cc nh sn xut thit b v cc nh tch hp

h thng cn phi xy dng ton b h thng i vi mi h thng mi c ci t.

Ngoi ra, nh sn xut v nh tch hp s s dng mt cng nghc quyn t mt


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nh cung cp ring l. Cng nghc quyn ny c th cung cp cc li ch trong

thi gian ngn, nng n lm cho nh sn xut v nh tch hp u gp kh khn

trong vic pht trin h thng ca h vt ra ngoi cng nghc quyn bi cc nh

cung cp. Ngoi ra, khi cng ngh ny l c quyn th cc nh cung cp cng ngh

su khin ng lai ca cng ngh m khng phi l cc nh sn xut v cc nh

tch hp.Vi vic chun ha cng ngh th cng ngh l c lp vi nh cung cp, nh

sn xut v ngi dng. Bt k nh cung cp no u c th la chn cung cp

cc h thng da trn cng ngh. Cc nh sn xut thit b, cc nh tch hp h thng

c th la chn xy dng h thng ca h da trn cng ngh t bt k nh cung

cp no.

Tiu chun ha cng ngh c mt u im ln l vic chp nhn cc u

khon. Khi cng nghc chun ha th cc nh cung cp, nh sn xut v cc nh

tch hp h thng c th d dng chn cc cng ngh m khng c ri ro t cc nhcung cp chnh na.

Vn chun ha cng ngh mng cm bin khng dy l mt thch thc

khng ch v mt cng ngh m cn trong iu khon ca cc t chc. Cc mng

cm bin khng dy bao gm nhiu cp khc nhau ca cng ngh, t cng ngh

truyn thng cng sut thp n k thut mng, nh tuyn, truy cp mc ng dng

v tch hp h thng cng ngh thng tin. Mi cp c nhng thch thc k thut

ring nhng quan trng hn l vic chun ha trong mi cp c qun l bi cc

nhm khc nhau.

1.2.4. Kh nng cng tc

Kh nng cng tc l kh nng cc thit b v h thng ca cc nh cung cp

khc nhau c th hot ng cng nhau. Kh nng cng tc l iu cn thit gia cc

nh sn xut khc nhau v gia mng cm bin khng dy vi cc c s h tng

mng hin c.

Khi c chun ha, mng cm bin khng dy phi c kh nng cng tc

nhiu mt. Cc nt cm bin phi tng thch vi nhau t lp vt l cho n lp ng

dng hoc lp tch hp. Kh nng cng tc lp vt l xy ra khi cc thit b t cc

hng khc nhau giao tip vt l c vi nhau. cp vt l, cc nt cm bin

khng dy phi thng nht trn cc vn nh l tn s v tuyn thc hin truyn

thng, kiu u ch tn hiu v tc d liu c truyn. cp mng, cc nt

phi thng nht vnh dng thng tin c gi v nhn trn cc knh vt l cng

nh cc nt mng c nh a ch nh th no, cc bn tin sc vn chuyn qua

mng bng cch no. lp ng dng hoc lp tch hp, cc nt cm bin phi chia


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s cch thc d liu c gi vo hoc ly ra t mng, cng nh lm th no

nt cm bin c thc truy cp ti t cc h thng bn ngoi.

1.3. Kin trc ngn xp giao thc ca mng cm bin khng dy

Kin trc ngn xp giao thc c s dng bi Sink v cc nt cm bin c

minh ha hnh 1.2. Kin trc ngn xp giao thc ny l s kt hp gia vn

ng lng v vn nh tuyn c quan tm n nng lng, cc giao thc tng

hp d liu v truyn thng hiu qu nng lng qua mi trng khng dy. Kin

trc ngn xp giao thc bao gm lp vt l, lp lin kt d liu, lp mng, lp giao

vn v lp ng dng, cng nh cc mt phng ng b, mt phng nh v, mt

phng qun l cu trc lin kt mng, mt phng qun l cng sut, mt phng qun

l di ng v mt phng qun l nhim v. Lp vt l xc nh cc yu cu cn thit

l cc k thut u ch, truyn dn, tip nhn d liu. Bi v mi trng c nhiu

v cc nt cm bin c th di ng, nn lp lin kt c trch nhim m bo vic

truyn thng tin cy nhcc k thut u khin li v qun l truy nhp knh thngtin thng qua lp MAC hn ch ti a xung t vi cc bn tin qung b ca nt

ln cn. Ty thuc vo cc nhim v cm bin th cc chng trnh ng dng khc

nhau c thc xy dng v c s dng trn lp ng dng. Lp mng quan tm

n vic nh tuyn d liu t lp giao vn. Lp giao vn gip duy tr dng d liu

nu ng dng mng cm bin yu cu. Thm vo l cc mt phng qun l nng

ng, di ng v qun l nhim v gim st nng lng tiu th, s di chuyn v

s phn phi nhim v gia cc nt cm bin. Nhng mt phng ny gip cc nt

cm bin phi hp vi nhau trong vic cm nhn mi trng v gim tng nng

ng tiu th.

Hnh 1.2: Kin trc ngn xp giao thc mng cm bin khng dy.Mt phng qun l nng lng qun l vic s dng nng lng ca mt nt

cm bin. V d, nt cm bin c th tt b thu ca n sau khi nhn c mt bn tin


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t mt nt ln cn. u ny nhm trnh vic nhn c cc bn tin trng lp. Ngoi

ra, khi mc nng lng ca mt nt cm bin xung thp th nt cm bin s thng

bo qung b n cc nt ln cn cc nt ln cn bit rng nng lng ca n

ang mc thp v n khng th tham gia vo vic nh tuyn cc bn tin. Nng

ng cn li ch dnh ring cho vic cm nhn v truyn d liu ca ring nt .

Mt phng qun l di ng pht hin v ng k s di chuyn ca cc nt cm bin,do mt tuyn ng n ngi dng cui lun lun c duy tr v cc nt cm

bin c th theo di cc nt ln cn ca chng. Bng vic nhn bit cc nt ln cn

th cc nt cm bin c th cn bng gia vic s dng nng lng v nhim v ca

chng. Mt phng qun l nhim v cn bng v lp lch cc nhim v cm nhn cho

mt khu vc c th. Khng phi tt c cc nt cm bin trong khu vc c yu

cu thc hin nhim v cm nhn cng mt thi m. Kt qu l, mt s nt cm

bin thc hin nhiu nhim v hn cc nt khc, ty thuc vo mc nng lng ca

chng. Nhng mt phng qun l ny l cn thit cc nt cm bin c th lm vic

cng nhau sao cho chng t c hiu qu cao nht v nng lng, vnh tuyn

d liu trong mng cm bin v chia s ti nguyn gia cc nt cm bin. Nu khng

c cc mt phng qun l ny th mi nt cm bin ch c th lm vic ring l. T

gc ton mng th s hiu qu hn nu cc nt cm bin c th cng tc vi nhau,

nh thi gian tn ti ca mng c thc ko di.

1.3.1. Lp vt l

Lp vt l c trch nhim la chn tn s, to tn s sng mng, pht hin tn

hiu v iu ch d liu.

1.3.2. Lp lin kt dliu

Lp lin kt d liu chu trch nhim ghp cc dng d liu, pht hin khung

d liu, u khin li v iu khin truy nhp knh truyn. N m bo s tin cy

ca cc kt ni m -im v im - a im trong mng.

1.3.2.1. iu khin truy nhp knh truyn

Giao thc MAC (Medium Access Control) trong mng cm bin a chng v

t t chc cn phi t c hai mc tiu. Mc tiu th nht l to c s h tng

mng. Bi v hng trm nt cm bin c th nm ri rc vi mt cao trong mttrng cm bin, nn c ch MAC cn phi thit lp cc lin kt truyn thng

truyn d liu. u ny to thnh c s h tng mng cn thit cho vic truyn

thng khng dy a chng v cung cp kh nng t t chc. Mc tiu th hai l chia

s hiu qu cc ti nguyn truyn thng gia cc nt cm bin. Nhng ti nguyn

ny bao gm thi gian, nng lng v tn s. Trong sut mt thp k qua, mt s


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giao thc MAC c pht trin cho cc mng cm bin khng dy gii quyt

nhng yu cu ny.

Vi bt k mt c ch truy nhp knh truyn no th vn hiu qu nng

ng l v cng quan trng. Mt giao thc MAC chc chn phi h trcc ch

hot ng tit kim nng lng cho nt cm bin. Vic bo tn nng lng r rng

nht l tt b thu pht khi khng cn thit. Mc d phng php tit kim nngng ny dng nh c li ng k cho vic tit kim nng lng nhng n c th

cn trvic kt ni mng. Sau khi b thu pht tt th nt cm bin khng th nhn

c bt k gi tin no t cc nt ln cn, bi v n b ngt kt ni mng. Ngoi ra,

vic bt v tt b thu pht v tuyn u c mt chi ph v nng lng tiu th do cc

th tc khi ng v tt b thu pht v tuyn u yu cu c v phn cng v phn

mm. C mt s ch hot ng hu ch khc cho nt cm bin khng dy ty

thuc vo s lng cc trng thi ca b vi x l, b nh, b chuyn i A/D v b

thu pht. Mi ch ny c c trng bi nng lng tiu th, thi gian trchuyn i gia cc ch nng lng .

1.3.2.2. iu khin li

Mt chc nng quan trng ca lp lin kt d liu l iu khin li (Error

Control - EC). Hai ch quan trng ca phng thc u khin li trong cc mng

truyn thng l sa li trc (Forward Error Control - FEC), yu cu lp li tng

(Automatic Repeat Request - ARQ). Li ch ca ARQ trong cc ng dng mng cm

bin b hn ch do vic tn hao nng lng khi truyn li v vic gii m cng phc

tp hn FEC, cng nh cc kh nng sa li cn phi c xy dng. Do , cc

m iu khin li n gin vi vic m ha v gii m t phc tp c th l cc gii

php hin ti tt nht cho cc mng cm bin. thit k mt c ch nh vy th

iu quan trng l phi hiu r v cc c tnh knh truyn.

1.3.3. Lp mng

Cc nt cm bin nm ri rc vi mt cao trong mt trng cm bin, c

thgn hoc ngay trong hin tng nhc ch ra trong hnh 1.1. Thng tin thu

thp c lin quan n hin trng c truyn n Sink c thc t xa so vi

trng cm bin. Tuy nhin, phm vi truyn thng ca cc nt cm bin b hn ch

khng cho php vic truyn thng trc tip gia mi nt cm bin vi Sink. u

ny i hi cc giao thc nh tuyn khng dy a chng gia cc nt cm bin v

Sink bng vic s dng cc nt cm bin trung gian thc hin chuyn tip. Cc k

thut nh tuyn hin c c pht trin cho cc mng Ad-hoc khng dy thng

khng ph hp vi cc yu cu ca mng cm bin. Lp mng ca cc mng cm

bin thng c thit k theo quy tc sau y:


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Vn hiu qu nng lng lun l vn c quan tm nht.

Cc mng cm bin ch yu l tp trung d liu.

Ngoi vic nh tuyn, cc nt chuyn tip c th tng hp cc d liu t cc

nt ln cn thng qua vic x l cc b.

Do s lng ln cc nt trong mt mng cm bin khng dy nn c th cc

nt khng c nhn dng duy nht v chng c th cn phi c nh a chda trn d liu v v tr ca chng.

Mt vn quan trng i vi vic nh tuyn trong cc mng cm bin

khng dy l vic nh tuyn c th da trn cc truy vn tp trung d liu. Da trn

cc thng tin c yu cu bi ngi dng, cc giao thc nh tuyn s xc nh cc

nt khc nhau trong mng cung cp thng tin yu cu. C th l ngi dng quan

tm nhiu hn n truy vn mt thuc tnh ca hin trng ch khng phi l truy

vn mt nt ring l. V d "cc khu vc c nhit trn 21oC" l mt truy vn ph

bin hn so vi "nhit c bi nt s #47".Mt chc nng quan trng khc ca lp mng l cung cp kt ni lin mng

vi cc mng bn ngoi chng hn nh cc mng cm bin khc, cc h thng ch

huy, iu khin v mng Internet. Cc nt Sink c th c s dng nh mt

Gateway kt ni vi cc mng khc, trong khi mt trng hp khc chng to ra

mt ng trc kt ni cc nt Sink vi nhau v kt ni ng trc vi cc mng

khc thng qua mt Gateway.

1.3.4. Lp giao vn

S pht trin ca cc giao thc lp giao vn l mt nhim vy thch thcbi v cc nt cm bin bnh hng bi nhng hn ch v phn cng nh l nng

ng v b nhhn ch. Do , mi nt cm bin khng th lu tr mt lng ln

d liu nh mt my ch trn mng Internet.

thc hin vic truyn thng trong mng cm bin khng dy th cc giao

thc lp giao vn yu cu hai chc nng chnh l: m bo tin cy v iu

khin tc nghn. Do ti nguyn hn ch v chi ph cao v nng lng nh hng

n tin cy ca cc cch truyn thng m cui n m cui c s dng

trong cc mng cm bin khng dy. Do vy cn thit phi c cc cchng tincy. Ngoi ra, tc nghn c th xut hin bi lu lng ln d liu c to ra trong

sut qu trnh xy ra cc s kin trong trng cm bin. Tc nghn cn c gim

thiu bi cc giao thc lp giao vn.


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1.3.5. Lp ng dng

Lp ng dng bao gm cc ng dng chnh cng nh mt s chc nng qun

l. Ngoi cc chng trnh ng dng c th cho mi ng dng th cc chc nng

qun l v x l truy vn cng nm lp ny.

Ngoi cc chc nng truyn thng trong ngn xp phn lp th cc mng cm

bin khng dy cng c trang b cc chc nng h trhot ng cho cc giiphp khcc xut. Trong mt mng cm bin khng dy, mi thit b cm bin

c trang b mt ng h cc b. Mi s kin c lin quan n s hot ng ca

thit b cm bin bao gm cm nhn, x l v truyn thng c kt hp vi thng

tin nh thi c u khin thng qua cc ng h cc b. V ngi dng quan tm

n thng tin phi hp t nhiu cm bin, nn thng tin nh thi c lin quan n

d liu mi thit b cm bin cn phi c thng nht. Ngoi ra, mng cm bin

khng dy c th sp xp th t chnh xc cc s kin c cm nhn bi cc cm

bin phn tn t m hnh ha chnh xc mi trng vt l. Nhng yu cu ngb ny dn n s pht trin cc giao thc ng b thi gian trong cc mng cm

bin khng dy.

S tng tc cht ch vi cc hin tng vt l i hi phi c cc thng tin

v tr c lin quan. Cc mng cm bin khng dy kt hp cht ch vi cc hin

ng vt l mi trng xung quanh. Thng tin thu thp c cn phi c kt

hp vi v tr ca cc nt cm bin cung cp ci nhn chnh xc v trng cm

bin. Ngoi ra, cc mng cm bin khng dy c thc s dng theo di cc

i tng nht nh trong cc ng dng gim st. Cc ng dng ny i hi thng tin

v tr a vo cc thut ton theo di. Ngoi ra, cc dch v da trn v tr v cc

giao thc truyn thng cng yu cu thng tin v tr. Do , cc giao thc nh v

c a vo ngn xp truyn thng.

Cui cng, mt s gii php qun l cu trc lin kt cng cn phi c duy

tr kt ni v vng ph sng ca mng cm bin khng dy. Cc thut ton qun l

cu trc lin kt cung cp cc phng thc hiu qu cho vic trin khai mng nhm

ko di thi gian tn ti ca mng v ph sng thng tin mt cch hiu qu. Ngoi

ra, cc giao thc u khin cu trc lin kt gip xc nh cc mc cng sut truyn

cng nh thi gian hot ng ca cc nt cm bin ti thiu nng lng tiu thtrong khi vn m bo kt ni mng. Cui cng, cc giao thc phn nhm c s

dng t chc mng thnh cc cm nhm ci thin kh nng mrng v ci thin

thi gian tn ti ca mng.

Bn cht s ph thuc vo tng ng dng ca cc mng cm bin khng dy

xc nh mt s thuc tnh c trng ring so vi cc gii php mng truyn

thng. Mc d nhng nghin cu v trin khai ban u ca cc mng cm bin


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khng dy tp trung ch yu vo vic truyn d liu trong mi trng khng dy

nhng mt vi lnh vc ng dng mi ca mng cm bin khng dy cng xut

hin. Chng bao gm cc mng cm bin v iu khin khng dy, trong mi nt

cm bin c thm cc thit b truyn ng chuyn i thng tin cm nhn c

thnh cc hnh ng tc ng n mi trng v cc mng cm bin a phng

tin khng dy h trlu lng a phng tin bao gm cc thng tin m thanh vhnh nh. Ngoi ra, hin trng mng cm bin khng dy gn y c p dng

vo trong cc mi trng hn ch nh thit lp mng di nc, trong lng t v

to ra cc mng cm bin khng dy di nc v trong lng t. Nhng lnh vc

nghin cu mi ny t ra nhng thch thc mi b sung m cha c quan tm

xem xt bi mt s gii php c pht trin cho cc mng cm bin khng dy

truyn thng.

S linh hot, kh nng chu li, cm nhn trung thc cao, chi ph thp v

mt sc m trin khai nhanh chng ca cc mng cm bin khng dy to ranhiu lnh vc ng dng mi cho vic cm nhn t xa. Trong tng lai, mt lot cc

lnh vc ng dng ny s lm cho cc mng cm bin tr thnh mt phn khng th

thiu trong cuc sng ca chng ta. Tuy nhin, vic thc hin cc mng cm bin

ny cn phi p ng c cc yu t nh kh nng chng li, kh nng mrng,

chi ph, phn cng, s thay i cu trc lin kt mng, mi trng v nng lng tiu

th. Bi v nhng rng buc ny rt nghim ngt v c th cho cc mng cm bin

nn cc k thut mng Ad-hoc khng dy mi l rt cn thit. Nhiu nh nghin cu

hin ang tham gia vo vic pht trin cc cng ngh cn thit cho cc lp khc nhau

ca ngn xp giao thc mng cm bin.

1.4. Chun truyn thng IEEE 802.15.4 cho mng cm bin khng dy

1.4.1. M hnh truyn thng trong mng cm bin khng dy

M hnh truyn thng cho cc nt mng cm bin khng dy c thc chia

thnh ba loi: m - im, m - a im v a im - im. Mi m hnh

truyn thng c s dng trong cc trng hp khc nhau. Nhiu ng dng s dng

kt hp cc m hnh truyn thng ny.

1.4.1.1. M hnh truyn thng m -imM hnh truyn thng m -im xy ra khi mt nt mng cm bin khng

dy truyn thng vi mt nt mng cm bin khng dy khc. Tuy nhin, vic truyn

thng c th c lin quan n cc nt mng cm bin khc. Trong hnh 1.3, hai nt

mng cm bin khng dy giao tip vi nhau nhng c hai nt mng cm bin khc

lin quan n qu trnh truyn thng, bi v chng chuyn tip cc gi tin gia cc

im u cui ca qu trnh truyn thng.


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Hnh 1.3: M hnh truyn thng m -im trong mng cm bin khng dy.1.4.1.2. M hnh truyn thng m -a im

M hnh truyn thng m - a im c minh ha nh hnh 1.4. M

hnh ny c s dng gi bn tin t mt nt ti mt s nt khc v c th l tt

c cc nt khc trong mng. M hnh truyn thng ny c thc s dng gi

mt lnh thit lp n cc nt trong mng.

Hnh 1.4: M hnh truyn thng im -a im trong mng cm bin khng dy.C nhiu hnh thc truyn thng trong m hnh im -a im. Ty thuc

vo tnh hung khc nhau th yu cu tin cy ca bn tin gi i l khc nhau. Nu

yu cu tin cy cao th giao thc truyn thng c th phi truyn li cc bn tin

cho n khi tt c cc nt nhn nhn thnh cng c gi tin. Nu tin cy

khng yu cu qu kht khe th giao thc truyn thng c th khng cn phi truyn

li bt k bn tin no v giao thc truyn thng coi knh truyn thng tin cy

cc bn tin c thn c cc nt nhn.

Nhiu cch v giao thc c thit k thc hin truyn thng m -

a im trong mng cm bin khng dy. Dng n gin ca truyn thng m -

a im l mng trn lan. iu ny c thc hin bng cch tng nt qung b bn

tin c gi i. Khi mt nt lng nghe c mt bn tin qung b c pht t mt

nt bn cnh, nt ny s qung b li bn tin ti tt c cc nt khc xung quanh n.

trnh vic gy nhiu ln nhau, mi nt chi mt khong thi gian ngu nhin


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trc khi gi li cc bn tin. Hiu qu ca cch ny l bn tin cng n tt c cc

nt trong mng, tr cc bn tin b mt do nhiu v tuyn hoc cc xung t v tuyn.

Mc d mt mng trn lan c th lm vic tt trong mt s trng hp nhng

n khng phi l cchng tin cy. Cc bn tin b mt do nhiu hoc xung t cn

c truyn li. t c tin cy trong truyn thng m -a im th giao

thc truyn thng phi pht hin c cc bn tin b mt v pht li chng.1.4.1.3. M hnh truyn thng a m -im

M hnh truyn thng a m -im thng c s dng thu thp d

liu t cc nt trong trng cm bin. Vi m hnh truyn thng a m -im,

mt vi nt gi d liu n cng mt nt. Nt ny thng c gi l Sink. Hnh 1.5

minh ha m hnh truyn thng a m -im.

Hnh 1.5: M hnh truyn thng a m -im trong mng cm bin khng dy.

Truyn thng a m -im c thc s dng thu thp d liu cmbin chng hn nh nhit t cc nt trong mng nhng n cng c s dng

truyn thng tin trng thi cc nt trong mng. Cc nt gi cc bo co trng thi

nh k ti Sink. Nt Sink sau bo co ton b hiu nng ca mng ti ngi

quan st bn ngoi.

Trong truyn thng a m - im, c th c nhiu hn mt Sink trong

mng. Nu ng dng khng xc nh mt nt c th d liu c thc gi ti th

mng s la chn gi d liu n Sink gn nht so vi nt gi. u ny cho php c

nhiu nt Sink trong mng nhm thu thp d liu t hiu qu cao hn. thit lp truyn thng a m -im th cc nt xy dng mt cu trc

cy vi gc ca n nt Sink. Sink thng bo s c mt ca n bi vic gi lp li

cc bn tin qung b xc nh rng nt gi cc bn tin ny c bc nhy bng khng

tnh t nt Sink. Cc nt hng xm lng nghe knh truyn v truyn li cc bn tin

thng bo chng c bc nhy l mt tnh t nt Sink. Ln lt, cc nt ln cn ca

chng s qung b thng tin l chng c bc nhy l hai tnh t nt Sink. Vi


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phng thc n gin ny, mi nt trong mng cui cng s bit c bao nhiu bc

nhy chng phi tri qua c tnh t nt Sink v bit c cc nt ln cn gn Sink

n. Khi gi mt gi tin, nt gi ch phi gi gi tin n nt ln cn gn Sink hn.

1.4.2. Chun truyn thng vt l cho mng cm bin khng dy

Chun IEEE 802.15.4 l mt chun truyn thng khng dy cho cc ng dng

cng sut thp v tc d liu thp. Tiu chun ny c pht trin cho mng cnhn (PAN) bi nhm lm vic trong Vin k thut n v in t (IEEE). Chun

IEEE 802.15.4 c tc d liu ti a l 250.000 bit/s v cng sut u ra ti a

1mW. Cc thit b IEEE 802.15.4 c mt phm vi ph sng hp trong vi chc mt.

im chnh trong cc c im k thut ca chun IEEE 802.15.4 l cho php cc b

thu pht chi ph thp v t phc tp, u ny lm cho chun IEEE 802.15.4 ph

bin vi mng cm bin khng dy. Nhiu cng ty sn xut cc thit b tun th theo

chun IEEE 802.15.4.

Bi s c mt khp ni ca chun IEEE 802.15.4 v s sn c ca cc b thupht v tuyn tng thch vi IEEE 802.15.4, nn gn y rt nhiu ngn xp v

tuyn cng sut thp c xy dng trn chun IEEE 802.15.4 nh l:

WirelessHART, ISA100a, IPv6 v ZigBee.

Tiu chun IEEE 802.15.4 xc nh 2 lp:

Lp vt l: Ch r cc bn tin c gi v c nhn trn cc knh truyn v

tuyn vt l nh th no.

Lp u khin truy nhp knh truyn (MAC): Ch r cc bn tin n t

cc lp vt l sc x l nh th no.Mc d chun IEEE 802.15.4 xc nh r mt vi cch lp vt l v

lp MAC nhng khng phi tt c mi ch dn u c s dng rng ri. V d

chun WirelessHART s dng cc ch dn lp vt l v nh dng tiu gi tin

lp MAC nhng khng phi tt c cc quy nh lp MAC c s dng.

Kch thc ti a gi tin trong chun IEEE 802.15.4 l 127 byte. Cc gi tin

c kch thc nh bi v chun IEEE 802.15.4 c s dng cho cc thit b vi tc

d liu thp. Do lp MAC thm vo phn tiu cho cc gi tin nn lng d

liu dnh sn cho giao thc lp trn hoc lp ng dng vo khong t 86 n 116byte. Do vy, cc giao thc lp trn thng thm vo cc cch phn mnh cc

phn d liu ln hn thnh nhiu khung theo chun 802.15.4.

Cc mng IEEE 802.15.4 c chia thnh cc mng PAN nh hnh 1.6. Mi

mng PAN c mt u phi vin PAN v mt tp cc thnh vin mng PAN. Cc

gi tin c truyn qua mng PAN mang 16 bit nhn dng cho mng PAN xc

nh mng PAN no m gi c gi n. Mt thit b c th tham gia vo mt


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mng PAN nh l mt u phi vin PAN v cng ng thi tham gia l thnh vin

mng PAN trong mt mng PAN khc.

Chun IEEE 802.15.4 xc nh hai loi thit b l: Thit b c chc nng y

(FFDs) v thit b c chc nng hn ch (RFDs). Cc FFDs c nhiu kh nng

n RFDs v c thng vai tr nh mt u phi vin PAN. RFDs l cc thit b

n gin hn c xc nh d dng hn trong vic ch to vi gi thnh r hn.RFDs ch c th truyn thng vi FFDs. Cc FFDs c th truyn thng c vi c

RFDs v FFDs.

Hnh 1.6: Mt mng IEEE 802.15.4 vi cc nt FFDs th hin nh cc chm en vcc nt RFDs th hin bi cc chm trng. Hai FFDs l iu phi vin PAN trong haimng PAN c biu din bi nhng vng trn en. Mng PAN bn phi bao gm

hai FFDs nhng ch mt FFD l iu phi vin PAN.Mc d chun IEEE 802.15.4 nh ngha ba loi cu trc mng c h trl

hnh sao, mng mt li v hnh cy nhng hu ht cc giao thc hot ng lp

trn khng s dng cc cu hnh mng ca 802.15.4. Thay vo , chng xy dng

nhng cu trc lin kt mng ca ring n pha trn lp MAC 802.15.4. V l do

, chng ta khng i vo chi tit cc cu trc lin kt mng c nh ngha bi

chun IEEE 802.15.4.

1.4.2.1. nh dng a ch theo chun IEEE 802.15.4

Mi nt trong mng theo chun IEEE 802.15.4 c mt a ch 64 bit nhn

dng thit b duy nht. Do kch thc gi tin b gii hn bi chun IEEE 802.15.4,

nn di 64 bit a ch l khng kh thi. Do , chun IEEE 802.15.4 cho php cc

nt s dng a ch vi di 16 bit. Cc a ch ngn c gn bi u phi vin

PAN v ch c gi tr trong khun kh ca mt PAN. Cc nt c th la chn gi

gi tin bng cch s dng c hai nh dng a ch.

a chc vit di dng h thp lc phn (Hexa) phn cch nhau bng du

hai chm. Mt v d v di mt a ch 802.15.4 l 00:12:75:00:11:6 e:cd: fb.


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Hnh 1.7 l mt v d v hai a ch IEEE 802.15.4 l mt a ch di v mt a ch

ngn.

Hnh 1.7: Hainh dng a ch h trIEEE 802.15.4l a ch di (64 bit) v a ch ngn (16 bit).

Cc a ch di l duy nht trn th gii v mi thit b IEEE 802.15.4 c

gn mt a ch khi c sn xut. Mi nh sn xut yu cu 24 bit nhn dng duynht OUI ca nh sn xut (Organizational Unique Identifier) ly t t chc IEEE.

Cc OUI c s dng nh l 24 bit a chu tin ca thit b. Cn li 40 bit c

gn bi nh sn xut v phi l duy nht cho mi thit b.

Cc a ch ngn c gn bi cc u phi vin mng PAN. Mt a ch

ngn ch c hiu lc trong phm vi mng PAN . Tuy nhin, mt thit b vi mt

a ch ngn c th truyn thng vi cc thit b bn ngoi mng PAN bng cch

mang thm 16 bit nh danh mng PAN ca n v mng PAN ca thit bch trong

mi bn tin c gi i. Tiu chun IEEE 802.15.4 khng chnh bt k thut tonc th no sc s dng bi mt u phi vin PAN khi gn cc a ch ngn

trong phm vi mng PAN.

1.4.2.2. Lp vt l theo chun IEEE 802.15.4

Lp vt l xc nh tn s v tuyn vt l, k thut u ch v m ha tn

hiu. Chun IEEE 802.15.4 hot ng trn 3 bng tn s v tuyn c cp php

min ph. Bi nhng quy nh khc nhau v tn s v tuyn, nn tn sc cp

php cc nc trn th gii cng khc nhau. Ti Hoa K, chun IEEE 802.15.4 s

dng bng tn 902-982MHz. Ti chu u, chun IEEE 802.15.4 s dng bng tn868-868.8MHz. Cc nc cn li th gii, chun IEEE 802.15.4 s dng bng tn

2400-2483.5MHz.

Chun IEEE 802.15.4 nh ngha 26 knh hot ng khc nhau. Trong mi

ng tn c quy nh mt s knh nhc ch ra trong hnh 1.8. Channel 0 c

quy nh ch chu u v nm trn bng tn 868MHz. Cc knh t 1-10 c quy

nh chHoa K trn bng tn 902-982MHz. Khong cch gia cc knh l 2MHz.


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Cc knh t 11-26 c quy nh trn bng tn 2,4 GHz. Khong cch gia cc knh

l 5MHz.

Hnh 1.8: Chun IEEE 802.15.4 quy nh 26 knh v tuyn vt l.

Chun IEEE 802.15.4 s dng hai loi u ch v tuyn ty thuc vo tn sknh. Cc knh t 0-10 s dng kho dch pha nh phn (BPSK), trong khi cc

knh t 11-26 s dng kho dch pha vung gc (QPSK). Trn tt c cc knh,

chun IEEE 802.15.4 s dng u ch tri ph chui trc tip (DSSS).

Ging nh k thut u ch, tc bit l ph thuc vo knh v tuyn. Tc

bit ca knh l 0 l 20.000 bit/s. i vi cc knh t 1-10, tc bit l 40.000

bit/s v cho cc knh 11-26 tc bit l 250.000 bit/s.

Hnh 1.9: Cc knh 11-24 IEEE 802.15.4 chng cho ln cc knh 802.11. Knh 25v 26 khng c bao bc bi cc knh 802.11. Khi cc knh 1, 6 v 11 ca 802.11c s dng, hai knh 15 v 20 ca 802.15.4 khng bnh ng bi 802.11.

Cc knh v tuyn IEEE 802.15.4 trong bng tn 2.4GHz chia s tn s v

tuyn ca chng vi chun IEEE 802.11 (WiFi) v c mt s chng ln vi cc knh

802.11. Bi v chun IEEE 802.11 c mt cng sut u ra cao hn nn lu lng

theo chun 802.11 lm nhiu lu lng theo chun 802.15.4. Hnh 1.9 cho thy s

chng ln gia chun 802.15.4 v chun 802.11. Tt c knh theo chun 802.15.4


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ngoi tr knh 25 v 26 c bao bc bi cc knh theo chun 802.11. Khi cc knh

1, 6 v 11 ca chun 802.11 c s dng th c 2 knh ca chun 802.15.4 (l knh

15 v 20) khng thy s can nhiu t lu lng ca chun 802.11.

Lp vt l cng cung cp cc ccho cng sut v tuyn ca mt knh

cho trc. Kt qu ca php o ny c s dng lp MAC bit mt nt no

c thang truyn d liu trn mt knh c th v u phi vin qut cc knh c

sn trong mng.

ch pht hin cng sut v tuyn cng c s dng h trcchnh

gi knh trng CCA (Clear Channel Assessment). Trong , lp vt l c thnh

gi bit c mt nt no hin ang truyn dn qua knh v tuyn. u ny

c thc hin bng mt trong ba cch sau: Th nht l o cng sut v tuyn v so

snh n vi mt mc cng sut ngng c xc nh trc. Th hai l thc hin

gii u ch tn hiu v tuyn n xem n c phi l mt tn hiu hp l theo

chun 802.15.4. Th ba l s kt hp ca phng php pht hin cng sut v tuynv phng php iu ch tn hiu. Cch CCA c s dng bi lp MAC kim

sot s truy nhp knh truyn v tuyn.

1.4.2.3. Lp u khin truy nhp knh truyn theo chun IEEE 802.15.4

Mc ch ca lp MAC l kim sot truy nhp vo cc knh truyn v

tuyn. Bi v knh truyn v tuyn c chia s gia tt c cc nt gi v nt nhn

trong mt khu vc ln cn vi nhau nn lp MAC cung cp cch cc nt xc

nh khi no knh nhn ri v khi no l an ton gi cc bn tin.

Lp 802.15.4 MAC cung cp cch qun l truy nhp knh, xc nhn s hpl cc khung n v xc nhn s tip nhn khung. Ngoi ra, 802.15.4 MAC cung cp

cc cch ty chn cho vic a truy nhp phn chia thi gian (TDMA) truy nhp

knh truyn. Trong , u phi vin PAN chnh cc khe thi gian cho thit b

trong mng PAN v thc hin vic lp lch trnh thng qua s truyn ti cc bn tin

bo hiu. y l ch bo hiu, tuy nhin khng c s dng rng ri bi cc

giao thc chy trn chun 802.15.4.

Vic qun l truy nhp knh truyn thc hin theo cch CCA c h tr

bi lp vt l. Trc khi gi mt gi tin, lp MAC yu cu lp vt l thc hin mtkim tra CCA. Nu CCA nhn thy rng mt nt khc hin ang s dng knh

truyn th lp MAC s khng thc hin vic truyn gi tin ca n. Thay vo , lp

MAC si mt thi gian nht nh v th gi li gi tin mt ln na.

Lp MAC thc hin xc nhn s hp l cc khung n bng vic tnh ton

kim tra d vng 16 bit (CRC) ca ton b khung. CRC c s dng kim tra

cc li truyn trong khung v c tnh ton bi nt gi khung. N c thm vo


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cc gi tin c truyn i. Nu CRC c tnh ton bi nt nhn khng khp CRC

cui khung th nt nhn s loi b khung.

Lp MAC cung cp mt cch tng xc nhn cc khung d liu. Nu mt

khung n c thit lp bit xc nhn th lp MAC s gi i mt khung xc nhn.

Khung xc nhn chc gi i khi a chch ca khung n ging a ch ca

thit b v nu CRC ca khung n hp l. Khung xc nhn khng c nh a chr rng n nt gi khung d liu, m c qung b n tt c cc nt. Chnh u

ny dn n vic nhiu giao thc lp trn chy trn chun 802.15.4 thc hin cc c

ch xc nhn ca ring chng.

1.4.2.4. Cu trc khung dliu theo chun IEEE 802.15.4

Cc giao thc truyn thng xc nh mt nh dng gi tin chung sao cho tt

c cc nt bit cch xy dng v phn tch cc gi tin t nhng nt khc. nh

dng gi tin bao gm ba phn l: Phn tiu , phn d liu v phn kt thc

khung. Phn tiu bao gm d liu u khin nh cc a ch, cc s th t v ccc. Phn d liu l d liu ca lp pha trn. Do , cu trc ca phn d liu thng

thng khng xc nh nhng c chuyn n cc giao thc lp trn xc nh

r. Phn kt thc khung thng cha mt kim tra tng hoc cc ch k mt m.

Phn kt thc khung ny c thc tnh ton trong khi gi tin c truyn i. Phn

kt thc ny sc gi i sau khi phn cn li ca gi tin c gi.

Hnh 1.10: Lp vt l IEEE 802.15.4 v cc nh dng tiu lp MAC.Chun IEEE 802.15.4 nh ngha mt nh dng gi tin chung cho tt c cc

gi tin c truyn i. nh dng gi bao gm mt phn lp vt l v mt phn lp

MAC. Lp vt l b sung phn tiu ng b ha v lp MAC b sung mt phn

tiu v phn kt thc khung. nh dng phn tiu c minh ha trong hnh

1.10.

Phn tiu c thm vo bi lp vt l bao gm mt mu khung

(Preamble), mt bt u gii hn khung SFD (Start of Frame Delimiter) v mt

trng di. Mu khung c s dng ng b ha nt gi v nt nhn

nt nhn c th nhn c chnh xc gi tin pha sau. Bt u gii hn khung SFD


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bo cho nt nhn bit c s kt thc phn mu v bt u khung. Trng

di 1 byte bo cho nt nhn bit c bao nhiu byte pha sau. Chiu di ti a ca

gi tin l 127 byte.

Phn tiu lp MAC gn trc tip ngay sau phn tiu lp vt l. Phn

tiu lp MAC c hai byte iu khin, c gi l iu khin khung. Phn cha

cc c bo cho nt nhn bit cch phn tch c phn cn li ca tiu cngnh cc c xc nh xem cc khung c cn phi xc nhn hay khng. Sau cc byte

iu khin khung l mt byte s th t. S th tc s dng kt hp vi cc

gi tin xc nhn. Gi tin xc nhn mang cng s th t vi gi tin d liu.

Sau cc byte s th t v iu khin khung l cc trng a ch. Chng cha

a ch ca nt gi gi tin v nt nhn gi tin cng nh cc nhn dng mng PAN

pha gi v pha nhn. Tt c cc trng a ch ny l ty chn. S c mt ca

chng c ch ra bi cc c trong trng u khin khung. Cc trng a ch

c s dng bi pha thu xc nh xem mt gi tin nhn c c phi dnh chon hay khng. Theo sau cc trng a ch l trng bo mt ty chn cha d liu

cho qu trnh x l bo mt, chng hn nh trng kim tra tnh ton vn bn tin

bng mt m MIC (Message Integrity Check).

D liu theo sau phn mo u lp MAC v n c th di t 86 n 116 byte.

di ca phn d liu ph thuc vo cc trng ty chn trong lp MAC c s

dng. Cu trc phn d liu trong khung 802.15.4 khng c xc nh bi chun

IEEE 802.15.4 nhng c xc nh bi cc giao thc hoc cc ng dng chy trn

chun 802.15.4.

pha cui ca gi 802.15.4 l chui kim tra khung (FCS - Frame Check

Sequence), n cha CRC m lp MAC s dng kim tra nu nh cc gi tin n

cn c loi b khi c cc bit li.


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Chng 2. PHN CNG CHO MNG CM BIN KHNG DY

2.1. Cu trc phn cng ca nt cm bin khng dy

Cu trc phn cng ca mt nt mng cm bin khng dy c minh ha

trong hnh 2.1 bao gm bn thnh phn chnh.

Hnh 2.1: Cc thnh phn chnh trong cu trc phn cngca mt nt cm bin khng dy.

Thit b truyn thng: Thit b ny cho php cc nt cm bin c kh nngtruyn thng vi nhau. Thit b truyn thng l mt b thu pht v tuyn c

kt ni vi mt anten.

B vi u khin: B vi u khin u khin cc hnh vi hot ng ca nt

cm bin. N l mt b vi x l nh trn chy phn mm ca nt mng

cm bin.

B cm bin: Cho php cc nt cm bin c kh nng tng tc vi th gii

vt l.

Ngun in: Cung cp nng lng cho nt cm bin hot ng.

Hnh 2.2: Bo mch MicaZ ca hng Crossbow Technology.Hnh 2.2 minh ha cc thnh phn cbn ca mt nn tng phn cng n

hnh, l bo mch mu th nghim MicaZ ca hng Crossbow Technology. N bao

gm b vi u khin, ngun n, b thu pht v tuyn v cc kt ni m rng


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kt ni vi cc cm bin. Ngun nng lng l mt b pin gm hai t bo pin AA.

B thu pht v tuyn c gn pha bn trong ca bo mch. H thng s dng mt

ng-ten bn ngoi gn lin vi bo mch. Bo mch khng cha bt k mt cm bin

no. Cc cm bin c thc gn vi bo mch thng qua cc kt ni mrng. V

vy chng ta c th s dng bo mch nh mt h thng to mu cho nhiu ng dng

khc nhau.V dtrn l mt bo mch mu c s dng khi th nghim vi mng cm

bin khng dy. Vi nhng sn phm ng dng cui cng th cc phn cng ca nt

cm bin thng c tch hp trn cng mt sn phm, lm cho phn cng nh gn

n. Chng ta s tp trung n cc thnh phn phn cng c bn ca mt nt cm

bin l: Thit b truyn thng, b vi u khin, cc cm bin v ngun n.

2.1.1. Thit b truyn thng

Thit b truyn thng cho php cc nt cm bin c th truyn thng vi nhau.

Thit b truyn thng thng l mt b thu pht v tuyn. Mt b thu pht v tuync c hai chc nng l va pht v va nhn bn tin v tuyn.

Cc loi b thu pht v tuyn khc nhau th c kh nng x l khc nhau. Mt

s b thu pht v tuyn n gin ch lm nhim v gi v nhn cc bit thng tin,

trong khi nhiu b thu pht v tuyn c thng gi thng tin thnh cc gi tin, nh

dng phn tiu v thm ch c m ha v gii m d liu bng cch s dng

phng php m ha bo mt.

Trong s cc thnh phn phn cng ca mt nt cm bin khng dy th b

thu pht v tuyn thng l thnh phn tiu tn nng lng nht. So snh vi mctiu th nng lng ca b vi u khin hoc cc cm bin th b thu pht v tuyn

thng s dng nng lng gp mi ln. Nguyn nhn l do yu cu x l u ch

v gii u ch tn hiu v tuyn. i vi b thu pht v tuyn cng sut thp th ch

mt phn nh cng sut tiu thc s dng gi tn hiu v tuyn.

Bi v b thu pht v tuyn l thnh phn tiu tn nng lng nht v vic

lng nghe cng tn km nh gi d liu, nn b thu pht v tuyn phi c tt

tit kim nng lng. Tuy nhin, khi b thu pht v tuyn tt th n khng th

nhn c bt k d liu no. hnh thnh mng a chng th cc b thu pht vtuyn ca tt c cc nt trong mng phi c cch ng b no chng c th

nhn c d liu trong khi vn bo tn c nng lng.

Hnh 2.3 l mt v d v b thu pht v tuyn Radiocrafts cho nt cm bin

khng dy. Chip Radiocrafts cha c mt b thu pht v tuyn v mt vi u khin.

Cc b thu pht v tuyn c sn xut bi Texas Instruments vi tn gi l


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CC2430, tng thch vi cc chun v tuyn IEEE 802.15.4. N c kh nng truyn

v nhn cc gi tin ring l. Tc bit ca cc b thu pht v tuyn l 250 Kbits/s.

Hnh 2.3: B thu pht v tuyn CC2430 vi vi u khin 8051v ng-ten tch hp trn bo mch c sn xut bi Radiocrafts.

Kch thc ca bo mch l 1,2 x 1,0 cm2.2.1.2. B vi u khin

B vi u khin chy cc chng trnh phn mm ca nt cm bin v c

kt ni vi b thu pht v tuyn v cc cm bin. Vi u khin l mt b vi x l c

b nhtrong, bnh thi v phn cng kt ni vi cc thit b bn ngoi nh cc

cm bin v b thu pht v tuyn. Hnh 2.4 minh ha b vi u khin Atmel

ATTINY 2313.

Do hn ch v gi thnh v nng lng nn cc vi iu khin c s dng

trong cc nt cm bin n gin hn nhiu so cc b vi x l c s dng trong cc

my tnh c nhn. Thng thng, mt b vi u khin s dng trong nt cm bin

c vi KB b nhca chip v hot ng tc xung nhp mt vi MHz. Trong khi

, my tnh hin i c n hng Gbytes b nhv chy xung nhp mt vi Ghz.Bng 2.1 cho thy bn vi u khin thng c s dng trong cc nt cm bin

khng dy l: MSP430 ca Texas Instruments, ATmega128 t Atmel AVR, 8051

ca Intel v PIC18 t Microchip.

Hnh 2.4: B vi u khin Atmel ATTINY 2313 vi 20 chn. Cc b vi u khinATTINY 2313 c 2 KB b nhROM v 128 byte b nhRAM.


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Bng 2.1: Bng so snh cc b vi iu khin thng c s dngtrong cc nt cm bin khng dy

Loi vi

u khinNh sn xut RAM (KB) ROM (KB)

Dng tiu th

tch cc/ng (mA)

MSP 430xF168Texas

Instruments

10 48 2/0.001

AVR AT128 Atmel 8 128 8/0.02

8051 Intel 0.5 32 30/0.005

PIC18 Microchip 4 128 2.2/0.001

Vi iu khin c hai loi b nh: B nhchc (ROM) v b nhtruy nhp

ngu nhin (RAM). ROM c s dng lu tr m chng trnh phn mm cn

RAM c s dng cho cc d liu tm thi ca chng trnh phn mm. D liu

tm thi bao gm vic lu tr cc bin chng trnh v b nhm x l lu

ng v tuyn. Ni dung trong ROM ca nt cm bin c ghi vo khi n c

sn xut v thng khng b thay i sau khi nt c trin khai. Tuy nhin, vi

iu khin hin i cung cp mt cch ghi li ROM v n rt thun li cp

nht li phn mm cho cc nt cm bin sau khi cc nt c trin khai.

Ngoi b nhth b vi u khin cn c bnh thi v cch tng tc vi

cc thit b bn ngoi nh thit b truyn thng v tuyn v cc cm bin. Cc b

nh thi c thc s dng bi phn mm chy trn vi iu khin. Cc thit b bn

ngoi c kt ni vt l vi cc chn ca vi u khin. Cc phn mm giao tip vi

cc thit b bng cch s dng cc c chc cung cp bi vi u khin, thngthng dng mt cng ni tip hoc cc bus ni tip. Hu ht cc b vi u khin

u c b thu pht ng b/khng ng b (USART) giao tip vi cc cng ni

tip. Mt s USART c thc cu hnh lm vic nh mt giao din bus ngoi vi

ni tip (SPI) giao tip vi cm bin.

2.1.3. Cm bin

Cc nt cm bin khng dy tng tc vi mi trng vt l nh cc cm

bin. Cc cm bin c gn trn nt cm bin khng dy c th t rt n gin n

rt phc tp. Nhiu b cm bin n gin v c hnh thc v chc nng. V d nhcc cm bin nhit l mt bin trm trkhng ca n thay i theo nhit mi

trng.

2.1.4. Ngun cung cp

Mt nt cm bin khng dy bao gm nhiu thit bn t v cc thit b

in t cn nng lng. V vy, mi nt cm bin cn mt ngun cung cp nng

ng. Ngy nay, cc ngun nng lng ph bin l pin nhng trong mt s trng


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hp s dng cc t bo nng lng mt tri, p n v cc hnh thc tch tr nng

ng khc.

Ngy nay, pin l ngun nng lng ph bin nht cho cc nt cm bin khng

dy. Chng c nhiu hnh dng v kiu dng. i vi cc nt cm bin khng dy th

kch thc l mt vn , n gii hn c v lng nng lng c thc tch tr

trong pin cng nh vic la chn cc loi pin. Cc pin Lithium hin nay l ph binnht. Vi cng sut phn cng thp v phn mm qun l nng lng thch hp, mt

nt cm bin khng dy c th c tui i hng nm trn tiu chun t bo pin

Lithium.

Pin c th sc li rt ph bin trong nhiu loi thit bn t nhin thoi

di ng v my tnh xch tay nhng li khng thch hp cho cc nt cm bin khng

dy. Khng ging nh cc in thoi di ng v my tnh xch tay l nhng thit b

c vn hnh bi con ngi th cc nt cm bin khng dy hu nhc thit k

hot ng m khng cn su khin hoc gim st ca con ngi. Ngoi ra,nhiu nt cm bin c t ti nhng ni kh tip cn. V vy, trong nhng trng

hp ny s l khng thc t khi thc hin sc li pin cho cc nt cm bin.

Thay v s dng pin c th sc li, pin cho cc nt cm bin khng dy

thng c thit k mt ln duy nht duy tr ton b khong thi gian tn ti ca

nt cm bin. Bng vic s dng cc thit bn t tiu th t nng lng v phn

mm tit kim nng lng, mt nt cm bin c th c thi gian tn ti nhiu nm

trn mt pin kch thc tiu chun AA. Khi pin ht th cc nt cm bin c th

c thay th bng pin khc.2.2. Kho st mt s nn tng phn cng ph bin cho mng cm bin

khng dy

Trong thi gian qua, c nhiu nn tng phn cng c nghin cu v pht

trin cho mng cm bin khng dy. Cc mc thi gian ra i ca cc nn tng phn

cng ny c thc thy r trong hnh 2.5.

Hnh 2.5: Mc thi gian ra i cc nn tng phn cng.


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Cc nn tng phn cng c thc phn loi thnh hai loi cbn sau:

Cc nn tng phn cng mc thp: Cc nn tng phn cng ny c c

trng bi s hn ch ca n v kh nng x l, b nh v kh nng truyn

thng. Cc nn tng phn cng ny thng c trin khai vi s lng ln

thc hin nhim v cm nhn cng nh to s kt ni gia cc nt mng.

Cc nn tng phn cng mc cao: Ngoi nhim v cm nhn th cc nntng phn cng ny cn thc hin nhim v tng hp, x l d liu, kt ni

mng cm bin khng dy vi cc mng khc bn ngoi. Cc nn tng phn

cng ny i hi b vi x l c kh nng x l mnh hn, dung lng b nh

nhiu hn.

Bng 2.2, 2.3 tng hp cc c im chnh ca mt s nn tng phn cng

ph bin c thit k trong thi gian qua.

Bng 2.2: Bng so snh mt s nn tng phn cng mc thp.

Phn cng B vi u khin thu pht v

tuynn s trung tm Hu hnh

Mica2ATMega 128L, 8bit,128KB

program memory, 4KB SRAMChipcon CC1000

315/433/868/916MHz

TinyOS, SOS, Mantis

Mica2 Dot ATMega 128L, 8bit, 128KBprogram memory, 4KB SRAM

Chipcon CC1000 315/433/868/916MHz

TinyOS, SOS, Mantis

MicaZATMega 128L, 8bit , 128KB

program memory, 4KB SRAMChipcon CC2420 2.4 GHz

TinyOS, SOS, Mantis,Nano-PK, RETOS,

LiteOS

IRIS ATmega 1281, 8bit, 128KBprogram memory, 8KB SRAM

Atmel AT86RF230 2.4 GHz TinyOS, LiteOS

CricketATmega 128L, 8bit , 128KB

program memory, 4KB SRAMChipcon CC1000 433MHz TinyOS

EyesMSP430F149, 16bit, 60KB

program memory, 2KB SRAM

RFM TR1001 868 MHz TinyOS, PEEROS

EyesIFXv1

MSP430F149, 16bit, 60KBprogram memory, 2KB SRAM

Infineon TDA5250 868 MHz TinyOS

EyesIFXv2

MSP430F1611, 16bit, 48KBprogram memory, 10KB RAM

Infineon TDA5250 868 MHz TinyOS

BTnodeATmega 128L, 8bit , 128KB

program memory, 4KB SRAMChipcon CC1000 and

Bluetooth radio433 915MHz

and 2.4GHzTinyOS

Bng 2.3: Bng so snh mt s nn tng phn cng mc cao.

Phn cng B xl nh Cc kt ni trn bo mch Hu hnh

StargateIntel PXA255

Processor,

400MHz

64MB SDRAM,

32MB Flash

PCMCIA and compact flashconnector, 51-pin expansion Connector

for Mica2 Motes; Ethernet, RS232

Serial, JTAG, USB Connector via 51-pin Daughter Card Interface

Embedded

Linux

NetbridgeNB-100

Intel IXP420Xscale Processor,

266MHz

32MB RAM, 8MBFlash, 2GB USB

Flash Disk

Mica2, MicaZ, IRIS, Telos ConnectorEthernet, USB connector

Debian Linux

ImoteARM7 processor,

12MHz64KB SRAM,512KB Flash

I2C, UART, USB, JTAG connector TinyOS

Imote2Marvell PXA271Xscale Processor,

13 416MHz

256KB SRAM,32MB SDRAM,

32MB FlashMemory

Integrated 802.15.4 radio, support forexternal radio through SDIO, and

UART; USB client and host, 2xSPI,3xUART, Camera, I2C, I2S, GPIO,

AC97 connector

TinyOS, Linux,SOS


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2.3. Gii php thit k phn cng TUmote cho mng cm bin khng dy

Da vo kt qu nghin cu kho st v cu trc phn cng ca mt nt cm

bin khng dy, chng ti a ra gii php thit k nn tng phn cng TUmote

o th nghim hai tham s nhit v m ca mi trng. Hnh 2.6 minh ha s

cc khi chc nng trong thit k. Cc linh kin chnh m chng ti la chn

trong thit k bao gm:

Hnh 2.6: S khi TUmote.2.3.1. B vi iu khin MSP430

Trong gii php thit k ny, chng ti la chn b vi u khin 16 bitMSP430 F1611. y l b vi u khin rt tit kim nng lng ca hng Texas

Instruments. B vi iu khin MSP430 F1611 c 10KB b nhRAM, 48KB b nh

Flash. B vi u khin MSP430 F1611 c thit k cho nhng ng dng tiu th

ng lng thp v s dng c nhiu ch hot ng khc nhau.

Chng ti la chn b vi u khin MSP430 F1611 cho thit k bi v y l

dng vi iu khin rt tit kim nng lng v nhiu hu hnh cho mng cm

bin khng dy h trdng vi iu khin ny. Do vy, TUmote c th tng thch

d dng vi cc hu hnh ph bin hin nay nh TinyOS, Contiki. Vic ci t hiu hnh trn phn cng TUmote s cho php chng ti lp trnh phn mm ng

dng c thun tin v cc ti nguyn phn cng trn nt cm bin cng c qun

l mt cch hiu qu t tit kim c nng lng tiu th.


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2.3.2. B thu pht v tuyn CC2420

Trong bn thit k ny, chng ti s dng chip CC2420 ca hng Texas

Instruments. Chip CC2420 l mt chip thu pht tn hiu v tuyn cng sut thp theo

chun IEEE 802.15.4. Tuy nhin, vic ch to mch in tn s 2,4 GHz l mt vn

kh khn i vi cng ngh ch to mch in trong nc. khc phc vn

ny, chng ti la chn module thu pht v tuyn CC2424EM ca hng TexasInstruments. Trn module ny c tch hp sn chip CC2420.

2.3.3. Cm bin nhit , m

Chng ti s dng cm bin SHT 11. Cm bin ny c sn xut bi hng

Sensirion AG. Cm bin ny cung cp d liu u ra s. Cm bin c ch to theo

quy trnh CMOS v c kt hp vi b chuyn i A/D 14-bit. y l loi cm

bin tiu th nng lng thp v c kch thc nh gn. Cm bin ny c thc

s dng cho nhiu ng dng gim st mi trng.

2.3.4. B nhngoi

B nhngoi cho php TUmote tng kh nng lu tr ngoi b nhROM v

RAM trn vi iu khin MSP430 F1611. TUmote s dng b nhST M25P80. B

nhny cha 1024kB cho d liu v c chia thnh 16 segments, mi segment c

kch thc l 64kB. B nhny chia s cc ng truyn thng SPI vi b thu pht

v tuyn CC2420.

2.3.5. Kt ni mrng

Cho php TUmote kt ni vi cc cm bin tng t, mn hnh LCD v cc

thit b ngoi vi khc thng qua 18 chn kt ni mrng.

2.3.6. Giao tip USB

TUmote s dng FT232BM ca hng FTDI truyn thng vi my tnh.

thc hin truyn thng vi TUmote th FTDI driver cn phi c ci t trn my

tnh. Mt ng dng c th truyn thng vi TUmote bng vic mcng COM c

gn cho TUmote. TUmote truyn thng vi my tnh thng qua USART1 trn vi

iu khin MSP430. Vic lp trnh cho TUmote c th thng qua giao tip USB hoc

JTAG.

2.3.7. Ngun cung cp

S dng hai pin AA c in p mt chiu nm trong di t 2,7V n 3,6V.

Ngun nui cng c th ly trc tip t my tnh khi nt cm bin c kt ni vi

my tnh.


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2.4. Cng c phn mm u khin v thu thp dliu TU2C

Cng c phn mm TU2C (Thainguyen University Control and Collection)

bao gm hai thnh phn chnh l: Phn u khin v phn thu thp d liu. Hnh

2.7 minh ha kin trc phn mm TU2C. Cng c phn mm TU2C cho php ngi

dng thc hin mt s chc nng sau:

Hnh 2.7: Kin trc phn mm TU2C. Cu hnh mng: Thng qua giao din phn mm TU2C, ngi dng c th

cu hnh cc tham s mng nh s ln truyn li gi tin, tn sut gi gi tin.

Lp trnh cho nt cm bin: Cng c phn mm TU2C cho php pht hin

tng cc nt ang c kt ni vi my tnh cng nh cho php ngi

dng kt ni hoc ngt kt ni gia cc nt cm bin vi my tnh. Chngtrnh ng dng trn nt cm bin c thc bin dch v np cho cc nt

cm bin thng qua giao din phn mm TU2C.

iu khin cc nt cm bin: Ngi dng c th gi cc lnh u khin n

cc nt mng trong trng cm bin nh thit lp nt Sink, gi lnh bt u

thu thp d liu, dng thu thp d liu...

La chn cc s liu thng k v v biu : D liu nhit , m mi

trng v cc thng s mng nh cng sut tiu th trung bnh ca cc nt

mng, s ln truyn k vng ETX, s gi tin nhn c, s gi tin b mt... sc gi v my tnh v c lu tr trong csd liu. Ngi dng c th

la chn quan st cc th, cc s liu thng k v mng.

2.5. Mt s hnh nh v phn cng TUmote v chng trnh phn mm

TU2C


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Hnh 2.8: S nguyn l TUmote.


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Hnh 2.9: S mch in TUmote.

Hnh 2.10: Hnh nh phn cng TUmote.

Hnh 2.11: Giao din chng trnh phn mm TU2C.


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Chng 3. HU HNH CHO MNG CM BIN KHNG DY

3.1. Gii thiu v phn mm ca nt cm bin khng dy

Mi hot ng ca mt nt cm bin khng dy c xc nh bi phn mm

chy trn b vi u khin trong cc nt cm bin. Cc chng trnh phn mm

thng c vit tng t nh cc chng trnh phn mm cho cc my tnh. Cc

chng trnh c vit bng mt ngn ng lp trnh, chng hn nh C v c bin

dch vi mt trnh bin dch m my cho vi iu khin. Cc m my c ghi vo

ROM ca b vi iu khin khi cc nt cm bin c sn xut. Khi cc nt cm bin

c bt ngun th b vi u khin s chy cc phn mm. Qu trnh ny c minh

ha trong hnh 3.1.

Hnh 3.1: Qu trnh pht trin phn mm cho mt nt cm bin khng dy.M ngun c bin dch thnh m my v c ghi vo ROM

trong b vi u khin ca nt cm bin.Mc d hon ton c th chy cc chng trnh phn mm cho vi u khin

m khng cn s dng mt hu hnh no nhng hu ht cc nt cm bin s

dng hu hnh. Bi v nhng hn ch v ti nguyn nn hu hnh cho cc nt

cm bin rt khc vi hu hnh cho my tnh. Cc hu hnh cho nt cm bin

nh hn nhiu v s dng t ti nguyn hn.Bi v nhng hn ch v nng lng v v chi ph nn cc nt cm bin

thng c b nh t hn nhiu so vi cc my tnh. Kch thc b nhch mt vi

KB, so vi hng GB b nhtrong cc my tnh ngy nay.

3.2. Hu hnh cho mng cm bin khng dy

Ging nh cc my tnh th cc nt cm bin khng dy cng s dng cc h

iu hnh. Chc nng c bn ca hu hnh bao gm vic tru tng ha ti


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nguyn cho cc thit b phn cng khc nhau, qun l ngt v lp lch cc nhim v,

iu khin ng thi v h trmng. Da trn cc dch vc cung cp bi hu

hnh, ngi lp trnh ng dng c th thun tin s dng cc giao din lp trnh ng

dng mc cao (APIs) c lp vi phn cng lp di.

Cc hu hnh cho mng cm bin rt khc vi cc hu hnh thng

dng c s dng trn my tnh v in thoi di ng. Cc hn ch v ti nguynb nh v sc mnh x l lm cho h u hnh quy m ln nh Microsoft

Windows, Mac OS X, hoc Linux u khng th s dng cho cc nt cm bin.

Ngay c phin bn thu nh, chng hn nh Microsoft Windows Mobile hoc Linux

da trn Android ca Google cng l qu ln.

Hu hnh cho cc nt cm bin c thit k ring vi cc yu cu c

trng ca nt cm bin v nhng hn chc trng ring b p t bi phn cng. B

nh hn ch lm cho m hnh lp trnh i vi nt cm bin c nhiu m khc.

Nhng hn ch v tc x l yu cu s dng ngn ng lp trnh cp thp, chnghn nh ngn ng lp trnh C.

Hu hnh cho nt cm bin khng c mt giao din ngi dng ging nh

hu hnh cho my tnh v ngi dng khng trc tip tng tc vi hu hnh

trn nt cm bin. Thay vo , hu hnh n su bn trong b vi u khin.

Thng thng, ch l ngi lp trnh vi nt cm bin mi tip xc vi hu hnh.

3.3. Nhng thch thc nh hng n vic thit k hu hnh cho mng

m bin khng dy

Hin nay c nhiu thch thc t ra cn phi c gii quyt, nhng nhng chnh l cc rng buc v ti nguyn ca phn cng nt cm bin v cc yu

cu ca ng dng mng cm bin khng dy. Nhng thch thc ch yu nh hng

n vic thit k hu hnh l:

Dung lng nh: Vi b nhb gii hn ch vi KB trn nt cm bin, i

hi hu hnh c thit k vi dung lng rt nh. y l c m c

bn ca hu hnh mng cm bin v cng l l do chnh m ti sao

nhiu hu hnh nhng khng th d dng ci t trn nt cm bin.

Hiu qu nng lng: Cc nt cm bin c thi gian s dng ca pin rt hnch. Mt khc, cc mng cm bin bo m mc tiu l vn hnh t 3 n 5

m. iu ny c ngha l, hu hnh mng cm bin c trin khai mt

ln v c k hoch vn hnh trong mt thi gian di.

H trthi gian thc: Hu ht cc ng dng cm bin nhphc v gim st

thng nhy cm vi thi gian. Trong cc ng dng , cc gi tin cn c


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chuyn tip v gi i mt cch kp thi, vn m bo thi gian thc l cn

thitp ng cho cc ng dng .

Kh nng cu hnh li: Liu cn thit cc nt cm bin c thc lp

trnh li sau khi mng cm bin khng dy c trin khai. Kh nng cu

hnh li h thng l mt c m cn thit ca hu hnh gip cho mng

cm bin c thc lp trnh li d dng v hiu qu. Stin li cho lp trnh: Cc ng dng mng cm bin l khc nhau v ty

theo yu cu. Do vy, s tin li cho lp trnh l mt u quan trng rt

ngn thi gian trin khai cc ng dng mng cm bin khng dy.

3.4. Kho st mt s hu hnh cho mng cm bin khng dy

Trong nhiu nm qua, chng ta thy xut hin nhiu hu hnh khc

nhau trong cng ng mng cm bin nhm d dng cho vic pht trin cc ng

dng mng cm bin khng dy. Sau y l mt s hu hnh ni bt.

3.4.1. H iu hnh TinyOS

Hnh 3.2: Kin trc h iu hnh TinyOS.

Hu hnh TinyOS, c pht trin UC Berkeley, c l l hu hnh

mng cm bin sm nht. Hnh 3.2 l kin trc hu hnh TinyOS. TinyOS cho

php mt kin trc mm do v tiu th ti nguyn thp. Vic lp trnh trn TinyOS

da trn cc thnh phn c kt ni vi nhau to mt ng dng ti thi m

thit k. Nhng tng tc thnh phn xy ra theo hai chiu, tc l mt thnh phn s

dng lnh c cung cp bi mt thnh phn khc. Ngoi ra, mt thnh phn c th

bo hiu cc s kin ti mt thnh phn khc. M hnh thc thi ca TinyOS bao gm

cc ngt v cc nhim v. Cc ngt c thc thi mc u tin cao hn v c th

c u tin thc thi trc cc nhim v. Cc nhim vc thc thi mc u tin

thp hn v c lp lch theo kiu vo trc ra trc FIFO (First In First Out). Cc

nhim v trong TinyOS c vit theo kiu run-to-completion (chy ti khi hon

thnh), v chng khng th ginh c u tin trc. cung cp s h tr tt hn

cho kin trc thnh phn v m hnh thc thi ca TinyOS, ngn ng nesC c thit

k cho vic lp trnh da trn TinyOS.


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Phin bn 2 ca TinyOS (T2) ci tin so vi phin bn 1 mt s mt. T2

cng cp s tra tng lng nhau, n l s lai ghp s phn chia theo phng ngang

v s phn chia theo phng ng, lm cho n d dng h tr cc nn tng phn

cng mi. Bn cnh nhng ci tin v kin trc, c mt s ci tin quan trng trong

s thc thi, bao gm h tr c lung (v d TinyThreads v TOSThreads trong

TinyOS phin bn 2.1), h trbo v b nh.3.4.2. H iu hnh LiteOS

Hnh 3.3: Kin trc hu hnh LiteOS.

H u hnh LiteOS c pht trin i hc Illinois tai Urbana

Champaign, c thit k cng cp mi trng lp trnh ng dng cho mng cm

bin khng dy ging nh UNIX truyn thng. Hnh 3.3 l kin trc hu hnh

LiteOS. Hu hnh LiteOS bao gm h thng file phn cp v wireless shell cho

php tng tc gia nhng ngi dng s dng cc lnh ging Unix. LiteOS h tr

cc ht nhn cho vic thc thi np tng cc ng dng a lung. Ngn ng lp

trnh s dng trong LiteOS l ngn ng lp trnh hng i tng c s dng mt

tp con ca C++. Phin bn 1.0 ca LiteOS c thm s h trcho cc nn tng phn

cng IRIS hin nay ca Crosbow. Hn na, n h trcch Virtual Battery v g

ri h thng t xa.


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3.4.3. H iu hnh Contiki

Hnh 3.4: Hu hnh Contiki.Cc thnh phn trong TinyOS c kt ni hon ton tnh to mt hnh nh

ng dng. Cch tip cn ny c th ti u s tiu th ti nguyn nhng cng km

hiu qu trong vic tng cu hnh li hay cp nht cc ng dng. gii quyt

vn ny, h iu hnh Contikic pht trin ti Vin khoa hc my tnh Thu

in c s thay i trong vic h tr cc thnh phn c th np t ng. khc

phc vn bt tin trong kiu lp trnh da trn s kin (trong TinyOS), Contiki h

trhot ng a lung cho php chuyn i gia cc lung ti nhng thi m c

xc nh bi ngi dng. Contiki cng h trcch lung nh (Protothreads).

Bng 3.1: So snh gia cc hiu hnh TinyOS, Contiki, LiteOS.c m TinyOS ContikiOS LiteOS

m cng b ASPLOS (2000) EmNets (2004) IPSN (2008)Website www.tinyos.net www.sics.se/ contiki www.liteos.net

thng tnh hay ng nh ng ng

thng nguyn khihay m un

Nguyn khi M un M un

trmng Active Message uIP. uIPv6, Rime File-Assisted

Ngn ng lp trnh nesC C LiteC++

p trnh da trn skin

C C C

tra lung C C C

p trnh li khng dy C C C

File h thng ELF, Matchbox Coffee Hierarchical Unix-like

trcc nn tngphn cng

Mica, Mica2, MicaZ,TelosB, Tmote, XYZ,IRIS, Tinynode, Eyes,

Shimmer

Tmote, TelosB, ESB,AVR MCU, MSP430

MCU

MicaZ, IRIS, AVRMCU

Cng c m phng TOSSIM, Power Tossim Cooja, MSPSim, Netsim Through AVRORA


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3.5. Hu hnh Contiki cho mng cm bin khng dy

3.5.1. Gii thiu

Hu hnh Contiki l hiu hnh m ngun m, c nghin cu, thit k

v pht trin bi mt nhm cc nh pht trin t vin khoa hc my tnh Thy n,

ngi ng u l Adam Dunkels. Nhm pht trin Contiki gm nhiu thnh vin

n t SICS, CISCO, cng nhiu t chc v cc trng i hc khc trn th gii. H

iu hnh Contiki c thit k cho cc vi u khin c b nhnh, vi thng s

2KB RAM v 40KB ROM. Nh, Contiki c s dng cho cc h thng nhng

v cc ng dng trong mng cm bin khng dy. Contiki bt u c nghin cu

t nm 2001 v pht hnh phin bn u tin Contiki 1.0 nm 2003. Hnh 3.5 cho

thy lch s pht trin ca Contiki trong nhng nm qua. Phin bn hin nay ca

Contiki l 2.6, vi nhiu thay i, b sung v pht trin vt bc. Trong thc t,

Contiki c ng dng trong nhiu d n nh gim st ng hm xe la, theo

di nc trong bin Baltic, Nhiu cch, tng trong Contiki c ng dngrng ri trong cng nghip. n hnh nh m hnh uIP c pht hnh nm 2001

c s dng trong h thng ng dng ca hng trm cng ty trong cc lnh vc

hng hi, thng tin v tinh, khai thc du m,; m hnh Protothreads c cng b

ln u tin nm 2005, n nay c s dng trong nhiu ng dng nh b gii

m k thut s v thit b cm bin rung khng dy.

Hnh 3.5: Lch s pht trin Contiki.Hu hnh Contiki c lp trnh bng ngn ng C v c nhng c m

ph hp vi cc h thng nhng v mng cm bin khng dy:

Contiki c chia thnh nhiu module hot ng c lp. Nh cc ng

dng c th s dng cc module mt cch linh ng v ch np nhng module

cn thit.


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ch hot ng u khin s kin lm gim nng lng tiu hao v hn ch

dung lng b nhcn s dng.

C th s dng IP trong mng cm bin thng qua uIP stackc xy dng

da trn nn TCP/IP.

C nhng module cho php c lng v qun l nng lng mt cch hiu

qu.

C ngn xp truyn thng RIME phc v cc giao thc dnh cho mng nng

ng thp mt cch hiu qu.

Bn cnh , Contiki cn cung cp nhng cng c h trm phng vi giao

din n gin, d s dng v h trtt nhng thit b trong thc t, phc v nhng

mc ch nghin cu, m phng v trin khai nhng giao thc mi.

3.5.2. Cu trc hu hnh Contiki

Bt k phin bn Contiki no cng gm 7 th mc l: apps, core, cpu, docs,

example, platform v tools.

Th mc apps: Cha cc tp tin ngun ca cc tin ch pht trin cho

Contiki. Chng c sn s dng v bao gm cc thit lp c bn ca cc

ng dng cho mng cm bin khng dy . ng dng tiu biu trong th mc

ny l trnh duyt web, my ch Web, FTP, email....

Thmc Core: Nh tn gi cho thy, n cha cc ht nhn ca hu hnh

Contiki. N cha khong 300 files, gn mt na trong s l tp tin tiu

cha cc khai bo v cn li l cc tp tin ngun cha ci t.

Thmc CPU: Cha cc b x l c th cho vic thc hin cc chc nng

khc nhau c s dng trong hu hnh.

Thmc Docs:c s dng trong vic xy dng ti liu cho Contiki.

Th mc Examples: Cha cc chng trnh v dn gin bt u vi

Hello-world, nh l bc u tin hng ti lp trnh ng dng trn

Contiki.

Thmc Platform: Bao gm thng tin c th lin quan n nn tng phn

cng cho cc nt cm bin nh ESB, Tmote Sky

Thmc Tools: L th mc cha cc cng c phn mm c bit. V d nh

Cooja l mt chng trnh Java m phng cho Contiki. Th mc ny cng

cha cc cng c cho cc nn tng phn cng c th. V dn hnh l cc

cng c cho nt cm bin Tmote Sky ca Sentilla.


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3.5.3. Ngn xp truyn thng trong hu hnh Contiki

Contiki cung cp cc ng dng trn nn IP gm c IPv4 v IPv6 thng qua 2

ngn xp truyn thng: uIP v Rime. Cc ng dng c th hot ng trn mt trong

hai giao thc uIP hoc Rime, hocng thi trn c hai giao thc. Bn cnh , cc

ng dng uIP c th hot ng da trn Rime v ngc li, cc ng dng trn nn

Rime cng c th hotng da trn nn uIP Ngn xp truyn thng trong huhnh Contiki c minh ha hnh 3.6.

Hnh 3.6: Kin trc giao thc mng trong Contiki.

hot ng ca cc ng dng trong Contiki c ch ra trong hnh 3.7.

Hnh 3.7: S hot ng cc ng dng trong Contiki.


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3.5.3.1. Ngn xp truyn thng uIP

Ngy nay, cng vi s thnh cng ca Internet, giao thc TCP/IP trthnh

tiu chun ton cu trong truyn thng. TCP/IP l giao thc cbn c s dng cho

cc ng dng truyn ti cc trang Web, gi - nhn email, gi file v nhng mng

Peer - to - Peer thng qua mng Internet. i vi cc h thng nhng, nu s dng

c TCP/IP s c kh nng kt ni h thng trc tip n mt mng ni b, hocthm ch l mt mng ton cu. Nhng thit b nhng c kh nng p ng c y

nhng c tnh ca TCP/IP s l nhng thit b c tnh u vit, c kh nng giao

tip mt cch y vi tt c cc thit b khc trong mng. Tuy nhin, s trin khai

giao thc TCP/IP truyn thng i hi qu nhiu ti nguyn gm c dung lng m

v b nhs dng, khng thc p ng trong cc h thng nhng 8 hoc 16 bit.

Xut pht t tng , ngn xp truyn thng uIP (hnh 3.8) c thit k

vi mc tiu ti u ha cc c tnh cn thit cho mt ngn xp TCP/IP y . uIP

ch c th hot ng vi mt giao din mng duy nht v bao gm cc giao thc: IP,ICMP, UDP, TCP. uIP c lp trnh bng ngn ng C bi Adam Dunkels mt

thnh vin trong t chc nghin cu v pht trin Contiki.

Hnh 3.8: Ngn xp truyn thng uIP.

3.5.3.2. Ngn xp truyn thng RIME

Ngn xp truyn thng RIME l mt cu trc phn tng giao thc trong mng

cm bin khng dy, t vic pht qung b n gin cho ti cc giao thcnh tuyn

phc tp hn trong mng. Ngn xp truyn thng RIME thc thi cc giao thc phc

tp vi nhiu thnh phn, mi phn li gm nhiu m un c to nn t nhng m

un nh ln gin hn. Di y l ton th t chc ca ngn xp truyn thng

RIME.


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Hnh 3.9: T chc ca RIME.

Hnh 3.10: Bm v Thao tc gi trong RIME.

c m ca ngn xp truyn thng RIME:

Phn chia thnh nhiu m un kh n gin vi kch thc nh.

Xy dng nhiu m un giao tip n gin:

- broadcast, unicast single hop.

- nh tuyn multihop: mesh, collect.


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Cc chc nng phc tp c thc hin qua cc phn lp n gin.

S dng cc hm callback thc hin cc hm x l khi nhn c gi tin,

bnh thi ht hn, kt ni li,

Kt ni phi c khi to trc khi s dng.

S dng mt bm gi cho tt c cc gi n v gi i (hnh 3.10). Khi gi

gi, cc ng dng lu gi vo b nhm v gi cc hm x l lin quan gi gi i. Khi nhn c mt gi, gi nhn c c lu trong bm gi,

ng thi ngn xp RIME gi cc hm callback tng ng x l gi u

vo.

3.5.4. M hnh lp trnh trong hu hnh Contiki

3.5.4.1. Lp trnh Event-driven

Lp trnh hng s kin (Event-driven) l mt m hnh lp trnh hiu qu v

b nh vit phn mm cho cc nt cm bin. Vi kiu lp trnh ny, phn mm

c vit nh l cc trnh x l s kin: Cc n m ngn gn m t lm th no

m h thng p ngc cc s kin. V d v cc s kin nh mt gi tin v

tuyn n t mt nt ln cn, s kin c d liu cm bin t mt trong cc b cm

bin v s kin t bnh thi. Khi s kin din ra, nt cm bin p ng bng cch

thc thi mt n chng trnh phn mm ca n.

Lp trnh hng s kin i hi t b nhhn so vi lp trnh a lung bi v

khng c lung no yu cu ngn xp b nh. Ton b h thng c th chy nh mt

lung duy nht v ch yu cu mt ngn xp duy nht.

3.5.4.2. Lp trnh Multithreads

a lung (Multithreads) l mt k thut lp trnh cho php nhiu chng trnh

c th chy ng thi trn mt b x l duy nht. Trong lp trnh a lung, mi

chng trnh c nh sn mt lung u khin ring v lung chy cng vi tt

c cc lung khc trong h thng. Mi lung c nh sn thi gian nht nh

chy trn b vi x l. cho php chy nhiu chng trnh cng mt lc, hu

hnh chuyn i gia cc lung chng cng nhau chia s b vi x l.

Lp trnh a lung c s dng rng ri trong cc hiu hnh thng dng,

cc lung t bo v ln nhau sao cho mt lung khng th tip cn mt lungkhc m khng i qua cc giao din quy nh. Khi cc lung t bo v ln nhau,

chng thng c gi l cc tin trnh thay v gi l cc lung.

i vi cc nt cm bin khng dy, tn ti mt vn a lung l mi lung

yu cu mt phn b nhca ring mnh gi trng thi ca cc lung ny, c

gi l ngn xp ca lung. Cc ngn xp cha cc bin cc b m lung s dng v

cc gi tr tr v cho cc hm m lung gi n, nhng cng bao gm mt lng


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ng i ln b nhkhng s dng. B nhny phi c cp pht bi v n cha

bit trc c c bao nhiu ngn xp b nh m mi lung cn dng. Do , b

nhngn xp thng vt qu s cp pht.

3.5.4.3. Lp trnh Protothreads

Protothreads l mt cch kt hp u im ca cc m hnh lp trnh hng

s kin v a lung. Protothreads l cch lp trnh c pht trin cho cc h thngc b nhhn ch, n kt hp m hnh lp trnh hng s kin v a lung theo mt

phng thc hiu qu v b nh. Vi Protothreads, chng trnh c cu trc theo

tun t, ging nh trong m hnh a lung, nhng s dng t b nh tng t nh

m hnh hng s kin. Protothreads c th thc hin c hiu qu trong ngn ng

lp trnh C m khng cn bt k ngn ng lp trnh bc thp hay cc thay i no vi

trnh bin dch. u hn ch l cc lp trnh vin phi lu tr cc bin mt cch r

rng khi cc Protothreads dng. Bi v cc Protothreads c thc hin bi ngn ng

C, nn chng rt tin li trn cc nn tng phn cng khc nhau.3.5.4.4. So snh ba m hnh lp trnh trong hu hnh Contiki

M hnh lp trnh Multithreads c kh nng thc hin ng thi mt chui cc

lung. Tuy nhin, cc lungi hi phi c thc hin trn nhng ngn nhring,

to ra chui cc lung u khin tun t.

Trong khi , m hnh lp trnh Event-driven ch hot ng trn mt ngn nh

v thc hin cc lung u khin ty theo cc s kin n. Do Event-driven i

hi b nht hn v cung cp cchu khin linh hot theo cc s kin.

Hnh 3.11: Phng thc s dng b nhca Multithreads v Event-driven.


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Hnh 3.12: Cc lung u khin trong Multithreads v Event-driven.

Nh s kt hp cc c tnh ca hai c ch Multithreads v Event-driven,

Protothreads c kh nng cung cp c chiu khin kiu Event-driven, cung cp

cc lung u khin lin tc, ng thi s dng dung lng b nh nh vi mt

ngn nhduy nht.Hnh 3.13 trnh by mt v d ca mt chng trnh c thc thi vi m hnh

lp trnh a lung v m hnh lp trnh hng s kin. Hnh 3.14 trnh by mt

chng trnh tng t c thc hin vi Protothreads. S khc bit gia m hnh

khng ch l cu trcon m m cn c chiu di caon m. Mc d m hnh lp

trnh hng s kin c nhiu dng m hn, nhng n hiu qu v b nh n so m

hnh a lung.

Hnh 3.13: V d v lp trnh a lung (tri) v lp trnh hng s kin (phi).


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Hnh 3.14: V d ca lp trnh Protothreads.3.5.5. Cc bnh thi trong hu hnh Contiki

Trong Contiki s dng 4 loi nh thi:

Timer: l loi nh thi thng, ch s dng lu li vt cc thi m khi

bnh thi ht hn. Rtimer: l loi nh thi thi gian thc, s dng gi mt hm ti mt thi

im c th no .

Event timer (etimer): c kch hot trong cc Process v s dng gi mt

s kin n Process khi bnh thi ht hn.

Callback timer (ctimer): C thc s dng bt k v tr no trong chng

trnh, c chc nng gi mt hm x l mi khi bnh thi ht hn. Ctimer

c s dng trong m un RIME ca Contiki.

3.5.6. Mt s hng dn bn vi hu hnh Contiki

3.5.6.1. Ci t mi trng pht trin vi hu hnh Contiki

c 1: Download v gii nn cc phn mm cn thit.

- Download VMware ti a ch: http://www.vmware.com/download/player/

- Download Instant Contiki ti a ch:

http://www.sics.se/contiki/instant-contiki.html

- Gii nn Contiki.

c 2: Ci t cc phn mm cn thit.- Ci t VMware.

c 3: MContiki-Instant bng VMware.

- Chy VMware


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Hnh 3.15: Giao din VMware Player.- M Instant-Contiki: Chn Open v chn ng dn n th mc Contiki

va gii nn. Chn Instant-Contiki.

Hnh 3.16: Chn ng dn n Instant-Contiki.-in username l user ri n enter. Mn hnh ng nhp hin ln:

Hnh 3.17: Giao din ng nhp username.-in password l user ri n enter .


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Hnh 3.18: Giao din nhp Password.- Giao din ca Instant-Contiki c ci trn Ubuntu.

Hnh 3.19: Giao din Instant-Contiki c ci trn Ubuntu.

3.5.6.2. Cc bc xy dng mt chng trnh ng dng vi Contiki

c 1: To mt th mc cho Project.

- Mi Project c t trong mt th mc. to mt th mc mi, u tin

chng ta mTerminal bng cch kch p vo biu tng Terminal trn mn

hnh.

- To 2 th mc: Mt th mc Project cha tt c cc Project c to ra

v mt th mc cha Hello-world-project.

mkdir projects

cd projects

mkdir hello-world-project

cd hello-world-project

c 2: To Makefile

- Sau khi to th mc cha Project, chng ta to mt Makefile m rng

chng trnh s c bin dch ng. Makefile c th c to ra bng cc


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trnh son tho nh (gedit, vi, emacs...). Trong v d ny, chng ta s dng

gedit. Cu lnh nh sau:

gedit Makefile &

- Chng ta g on vn bn sau vo Makefile.

CONTIKI=/home/user/contiki-2.x

include $(CONTIKI)/Makefile.include

Hnh 3.20: Son tho Makefile trong gedit.- Chng ta lu file ny li bng cch kch vo nt Save. By gichng ta c

th vit mt chng trnh u tin.

c 3: To mt file chng trnh

- Chng ta to mt file chng trnh chnh t tn l hello-world.c. Nu s

dng trnh son tho gedit, chng ta ch kch chn New document trn thc

n File.

- Chng ta g li on chng trnh sau:

#include "contiki.h"

PROCESS(hello_world_process, "Hello world process");

AUTOSTART_PROCESSES(&hello_world_process);

PROCESS_THREAD(hello_world_process, ev, data)

{

PROCESS_BEGIN();

printf("Hello, world!\n");

PROCESS_END();

}


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Hnh 3.21: Son tho chng trnh Hello-world trong gedit.

- Chng ta lu file chng trnh ny v t tn l hello-world.c.

c 4: Thit lp nn tng phn cng bin dch cho Project ny. S dng lnh

sau:

make TARGET=TUmote savetarget

c 5: Bin dch Project. S dng lnh sau:

make hello-world

c 6: Kim tra Project vi MSPsim. S dng lnh sau:

make hello-world.mspsimc 7: Chy Project trn phn cng TUmote

- Nu chng ta c phn cng TUmote c kt ni vi my tnh th by gi

chng ta c th np chng trnh hello-world vo TUmote. Chng ta g

lnh sau:

make hello-world.upload

- Sau khi vic lp trnh hon thnh, chng trnh hello-world ang c

chy trn TUmote. Chng ta c th xem kt qu ca chng trnh chy trn

TUmote bng cch g lnh:make login

3.5.6.3. Cng c m phng Cooja

COOJA l mt cng c m phng linh hot da trn nn tng Java c thit

k cho vic m phng mng cm bin chy hu hnh Contiki. COOJA m phng

h thng mng ca cc nt cm bin trong cc nt c th khc nhau v c phn

cng v phn mm chy trn nt cm bin.


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Hnh 3.22: Giao din ng dng m phng trn Cooja.

Giao din ca chng trnh rt trc quan v d s dng, vi mt mn hnh cho

php hin th cc qu trnh hot ng ca nt

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