mang cam bien khong day_sua

5/25/2018 Mang Cam Bien Khong Day_sua

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HC VIN CNG NGH BU CHNH VIN THNG

Khoa K thut in t I

**********

Ths. V Anh o- Ths. Trn Th Thc Linh

Bi ging:

MNG CM BIN KHNG DY

H ni, 7/2010


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MC LC

MC LC.................................................................................................................................. 2LI NI U............................................................................................................................ 6

DANH MC CC HNH V.................................................................................................... 8DANH MC BNG BIU...................................................................................................... 11CC THUT NG VIT TT............................................................................................... 12CHNG 1. GII THIU CHUNG....................................................................................... 17

1.1 C s h tng cho mng cm bin khng dy................................................................ 171.2 Mng cm bin khng dy v ng dng......................................................................... 191.3 Nhng kh khn ca mng cm bin khng dy............................................................ 26

1.3.1 Cc yu cu k thut................................................................................................ 261.3.2 Cc k thut yu cu................................................................................................ 28

1.4 Ti sao mng cm bin li khc vi cc mng khc?..................................................... 291..4.1 Mng Ad hc di ng v WSN.............................................................................. 29

1.4.2 Fieldbus and WSN ................................................................................................... 321.5 Cc k thut cho WSN................................................................................................... 33CU HI N TP CHNG 1............................................................................................. 34CHNG 2. KIN TRC NT N.................................................................................... 35

2.1 Cc b phn phn cng.................................................................................................. 352.1.1 Tng quan phn cng ca nt cm bin.................................................................. 352.1.2 B iu khin........................................................................................................... 362.1.3 B nh..................................................................................................................... 382.1.4 Thit b lin lc........................................................................................................ 382.1.5 Cc cm bin v c cu chp hnh.......................................................................... 462.1.6 Ngun cung cp ca cc nt cm bin.................................................................... 47

2.2 Tiu th nng lng ca cc nt cm bin..................................................................... 482.2.1 Cc trng thi hot ng vi mc tiu th cng sut khc nhau............................. 482.2.2 Tiu th nng lng b vi x l.............................................................................. 502.2.3 B nh..................................................................................................................... 522.2.4 Cc b thu pht v tuyn......................................................................................... 522.2.5 Mi quan h gia tnh ton v lin lc.................................................................... 542.2.6 Tiu th nng lng ca cc cm bin v c cu chp hnh................................... 55

2.3 Cc h iu hnh v mi trng thc hin..................................................................... 552.3.1 Cc h iu hnh nhng........................................................................................... 552.3.2 M hnh lp trnh v cc giao din lp trnh ng dng............................................ 562.3.3 Cu trc h iu hnh v ngn xp giao thc.......................................................... 582.3.4 Nng lng ng v qun l nng lng................................................................ 59

2.4 Mt s v d ca nt cm bin........................................................................................ 602.4.1 H Mica Mote.......................................................................................................... 602.4.2 Cc nt EYES .......................................................................................................... 602.4.3 Btnode ...................................................................................................................... 61

2.5 Kt lun.......................................................................................................................... 61CU HI N TP CHNG 2 ............................................................................................. 63CHNG 3. KIN TRC MNG......................................................................................... 64

3.1 Mng cm bin............................................................................................................... 643.1.1 Ngun v b cha n............................................................................................. 64

3.1.2 Mng mt bc nhy v a bc nhy................................................................... 653.1.3 a b cha v ngun............................................................................................... 663.1.4 Ba loi chuyn ng................................................................................................ 66


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3.2 Cc mc tiu ti u v h s cht lng......................................................................... 683.2.1 Cht lng dch v.................................................................................................. 683.2.2 Hiu qu nng lng............................................................................................... 693.2.3 Kh nng m rng................................................................................................... 703.2.4 Tnh bn vng.......................................................................................................... 70

3.3 Nguyn tc thit k WSN............................................................................................... 70

3.3.1 T chc phn b...................................................................................................... 703.3.2 X l trong mng..................................................................................................... 713.3.3 Tnh chnh xc v tin cy.................................................................................... 733.3.4 Tp trung d liu..................................................................................................... 733.3.5 Khai thc thng tin v tr.......................................................................................... 743.3.6 Khai thc cc m hnh hot ng............................................................................ 753.3.7 Giao thc da trn phn t v ti u lp giao nhau................................................ 75

3.4 Giao din dch v ca WSN........................................................................................... 753.4.1 Cu trc ca giao din ngn xp giao thc/ng dng............................................. 753.4.2 Cc yu cu cho giao din dch v ca WSN.......................................................... 76

3.5 Khi nim cng vo/ra.................................................................................................... 77

3.5.1 S cn thit ca cc cng vo/ra............................................................................. 773.5.2 Giao tip WSN vi Internet..................................................................................... 783.5.3 Giao tip Internet-WSN ........................................................................................... 793.5.4 Giao tip gia cc WSN.......................................................................................... 80

3.6 Kt lun.......................................................................................................................... 80CU HI N TP CHNG 3............................................................................................. 82CHNG 4. LP VT L..................................................................................................... 83

4.1 Gii thiu........................................................................................................................ 834.2 Knh v tuyn v c s truyn tin.................................................................................. 83

4.2.1 Cp pht tn s........................................................................................................ 834.2.2 iu ch v gii iu ch......................................................................................... 854.2.3 Cc nh hng ca truyn sng v nhiu................................................................ 884.2.4 Cc m hnh knh .................................................................................................... 934.2.5 Cng ngh tri ph.................................................................................................. 944.2.6 ng b v truyn gi tin........................................................................................ 954.2.7 Cht lng knh v tuyn v cc php o ci thin........................................... 97

4.3 Lp vt l v thit k b thu pht trong WSN................................................................ 984.3.1 S dng nng lng................................................................................................. 994.3.2 La chn s iu ch.......................................................................................... 994.3.3 Antenna .................................................................................................................. 100

CU HI N TP CHNG 4........................................................................................... 101

CHNG 5. CC GIAO THC MAC................................................................................ 1025.1. Cc nguyn tc c bn ca cc giao thc MAC (khng dy)..................................... 1025.1.1 Cc yu cu v rng buc thit k cho cc giao thc MAC khng dy................ 1025.1.2 Phn loi cc giao thc MAC................................................................................ 1045.1.3 Cc giao thc MAC cho WSN .............................................................................. 109

5.2 Cc giao thc h s lp y thp v khi nim thc dy (wakeup).............................. 1105.2.1 Cu hnh mng v vn qun l nng lng...................................................... 1115.2.2 S-MAC .................................................................................................................. 1135.2.3 Giao thc thit b trung gian.................................................................................. 116

5.3 Cc giao thc theo kiu cnh tranh.............................................................................. 1175.3.1 Cc giao thc CSMA............................................................................................. 118

5.3.2 PAMAS ................................................................................................................. 1185.4 Cc giao thc da trn lch trnh.................................................................................. 1205.4.1 LEACH .................................................................................................................. 120


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5.4.2 SMACS .................................................................................................................. 1225.5 Giao thc MAC ca IEEE 802.15.4............................................................................. 124

5.5.1 Kin trc mng, loi v vai tr ca nt.................................................................. 1265.5.2 Kin trc ca siu khung....................................................................................... 1275.5.3 Giao thc Slotted CSMA-CA ................................................................................ 128

5.6 Tng kt........................................................................................................................ 129

CU HI N TP CHNG 5........................................................................................... 130CHNG 6. CC GIAO THC LP LIN KT............................................................... 1316.1 Cc nhim v v yu cu c bn.................................................................................. 1316.2 Gim st li................................................................................................................... 132

6.2.1 Nguyn nhn v cc c tnh ca sai s truyn dn.............................................. 1326.2.2 Cc k thut ARQ................................................................................................. 1336.2.3 Cc k thut FEC................................................................................................... 1386.2.4 Cc s lai.......................................................................................................... 1436.2.5 iu khin cng sut............................................................................................. 1456.2.6 iu khin li........................................................................................................ 145

6.3 nh dng khung.......................................................................................................... 146

6.3.1 Cc s tng thch............................................................................................ 1496.3.2 Cc s kim tra tng trung gian........................................................................ 1506.3.3 Kt hp ti u kch thc gi tin v FEC............................................................. 152

6.4 Qun l tuyn............................................................................................................... 1536.4.1 Cc c tnh ca cht lng tuyn......................................................................... 1536.4.2 c lng cht lng tuyn.................................................................................. 155

6.5 Tng kt........................................................................................................................ 157CU HI N TP CHNG 6........................................................................................... 158CHNG 7. T TN V NH A CH...................................................................... 159

7.1 Cc nguyn tc c bn.................................................................................................. 1597.1.1 S dng cc a ch v cc tn trong cc mng (cm bin)................................... 1597.1.2 Nhim v qun l a ch....................................................................................... 1607.1.3 S duy nht ca cc a ch................................................................................... 1617.1.4 Phn phi v n nh a ch.................................................................................. 1627.1.5 nh a ch phn tip u.................................................................................... 163

7.2 Qun l tn v a chtrong cc mng cm bin khng dy ........................................ 1647.3 n nh cc a chMAC ............................................................................................. 1657.4. nh a ch theo a l v da trn ni dung............................................................. 167

7.4.1 nh a chda trn ni dung ............................................................................. 1687.4.2 nh a ch theo a l......................................................................................... 171

7.5 Tng kt........................................................................................................................ 172

CU HI N TP CHNG 7........................................................................................... 173CHNG 8. NG BTHI GIAN.................................................................................. 1748.1 Gii thiu v vn ng b thi gian.................................................................. 174

8.1.1 S cn thit ca vic ng b thi gian trong cc mng cm bin khng dy...... 1748.1.2 Cc kha nt v vn v chnh xc................................................................ 1758.1.3 Cc c im v cu trc ca cc thut ton ng b thi gian ............................ 1778.1.4 ng b thi gian trong cc mng cm bin khng dy....................................... 179

8.2 Cc giao thc da trn ng b my pht/ my thu.................................................... 1808.2.1 Giao thc ng b thi gian hng nh - Lightweight time synchronization protocol(LTS) .............................................................................................................................. 1808.2.2 Lm th no tng chnh xc v c lng lch...................................... 185

8.2.3 Giao thc ng b thi gian cho cc mng cm bin (TPSN).............................. 1888.3 Cc giao thc da trn s ng b my thu/my thu................................................... 1918.3.1 S ng b qung b tham kho (RBS - Reference broadcast synchronization) .. 191


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8.3.2 Phn tng tham chiu ng b thi gian (HRTS - Hierarchy referencing timesynchronization) ............................................................................................................. 197

CU HI N TP CHNG 8........................................................................................... 201CHNG 9. NH V V XC NH V TR................................................................... 202

9.1 Cc c im ca quy trnh nh v v xc nh v tr................................................. 2029.2 Cc phng php c th............................................................................................... 204

9.2.1 Phng php da trn s gn gi.......................................................................... 2049.2.2 Php c tam gic (triangulation) v php o ba cnh tam gic (Trilateration) .... 2049.2.3 Phn tch cnh........................................................................................................ 208

9.3 C s ton hc cho cc vn cnh............................................................................. 2099.3.1 Gii php vi ba nt neo v sa li cc gi tr khong cch................................. 2099.3.2 Gii quyt vn cc li khong cch.................................................................. 210

9.4 Xc nh v tr trong cc mi trng a bc nhy...................................................... 2119.4.1 S kt ni trong mt mng a bc nhy.............................................................. 2119.4.2 Vic c lng phm via bc nhy.................................................................. 2129.4.3 a bn cng tc v lp........................................................................................... 2139.4.4 M t v truyn lan vic xc nh v tr theo xc sut........................................... 215

9.5 Tng kt........................................................................................................................ 216CU HI N TP CHNG 9........................................................................................... 217CHNG 10: IU KHIN CU TRC LIN KT MNG (TOPOLOGY).................. 218

10.1.1 Cc ty chn cho vic iu khin cu trc lin kt mng................................... 21910.1.2 Cc kha cnh ca cc thut ton iu khin cu trc lin kt mng .................. 221

10.2 iu khin cu trc lin kt mng trong cc mng phng iu khin cng sut.... 22310.2.1 Mt s cc kt qu phc tp................................................................................ 22410.2.2 Cc gii hn ca cc tham s ch cht................................................................ 22510.2.3 Vi cu trc v giao thc vd............................................................................ 227

10.3 Cc mng phn tng xng sng............................................................................. 22910.3.1 ng c v nh ngha......................................................................................... 22910.3.2 Mt s xp x phn tn........................................................................................ 234

10.4 Mng phn tng phn nhm (clustering) ................................................................ 23710.4.1 nh ngha cc phnnhm .................................................................................. 23710.4.2 Mt tng c bn xy dng cc tp hp c lp......................................... 24010.4.4 Kt ni cc phn nhm........................................................................................ 24110.4.5 Quay cc ch huy phn nhm.............................................................................. 242

CU HI N TP CHNG 10......................................................................................... 243TI LIU THAM KHO...................................................................................................... 244


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6

LI NI U

Nhng tin b gn y trong thng tin v tuyn v in t cho php pht trin ccmng cm bin gi thnh thp. Mng cm bin c th c s dng trong cc ng dng khc

nhau nh chm sc sc kho, trongqun s hoc s dng trong gia nh. Mng cm binkhng dy (WSN) bao gm cc nt nh c kh nng cm bin, tnh ton v trao i thng tinv tuyn. Mt s giao thc chn ng, qun l nng lngv trao i dliu c thitk cho WSN vi yu cuquan trng nht l tit kim c nng lng. Cc giao thc chnng trong WSN c th khc nhau tu theo ng dng v cu trc mng. Ni chung, cc giaothc chn ng c chia thnh 3 loi da vo cu trc mng: ngang hng, phn cp hocda vo v tr. Ngoi ra, nhng giao thc ny c th c phn loi da theo a ng, yucu, hi/p, QoS v lin kt tu thuc vo ch hot ng.

Mng cm bin khng dy (WSN) c th hiu n gin l mng lin kt cc nt vi

nhau bng kt ni sng v tuyn , trong cc nt mng thng l cc (thit b) n gin,nh gn, gi thnh thp ... v c s lng ln, c phn b mt cch khng c h thng trnmt din tch rng, s dng ngun nng lng hn ch (pin), c thi gian hot ng lu di(vi thng n vi nm) v c th hot ng trong mi trng khc nghit (cht c, nhim,nhit ...).

Cc nt mng thng c chc nng cm ng, quan st mi trng xung quanh, theo dihay nh v cc mc tiu c nh hoc di ng ... Cc n t giao tip ad-hoc vi nhau v truynd liu v trung tmmt cch gin tip bng k thut a bc nhy.

Lu lng d liu lu thng trong WSN thng thp v khnglin tc. Do vy tit

kim nng lng, cc nt cm bin thng c nhiu trng thi hot ngv trng thi nghkhc nhau. Thng thng thi gian mt nt trng thi ngh ln hn trng thi hot ngrt nhiu.

Nh vy, c trng c bn nht phn bitmng cm bin v mng khng dy khcchnh l gi thnh, mt nt mng, phm vi hot ng, cu hnh mng, lu lng d liu,nng lng tiu th v thi gian trng thi hot ng.

Bi ging Mng cm bin khng dy gm 10 chng: 6 chng u do Ths. V Anho bin son v 4 chng sau do Ths. Trn Th Thc Linh bin son. Cun sch gii thiu

cho bn c nhng kin thc c bn v WSN nh cc tiu ch khi xy dng mt WSN v ccc im ca WSN nh lp MAC, lp lin kt d liu, cch t tn v nh a ch, c th:

Chng 1: Gii thiu chung

Chng 2: Kin trc nt n

Chng 3: Kin trc mng

Chng 4: Lp vt l

Chng 5: Cc giao thc MAC

Chng 6: Cc giao thc lp lin kt

Chng 7: t tn v nh a chChng 8: ng b thi gian


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Chng 9: nh v v xc nh v tr

Chng 10: iu khin cu trc lin kt mng

Tuy nhin, do thi gian bin son c hn nn cun bi ging cn c th c nhng thiust, rt mong c bn c gp . Cc kin phn hi xin gi v B mn K thut in t -Khoa K thut in t I, Hc vin Cng ngh Bu chnh Vin thng.

Xin trn trng gii thiu!

Nhm tc gi


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DANH MCCC HNH V

Hnh 1.1 Mng im im..................................................................................................... 21Hnh 1.2 Mng im a im................................................................................................ 21Hnh 1.3 Mng a im a im........................................................................................... 22

Hnh 1.4 S nguyn l mng chia s kt ni dng ad hoc................................................... 30Hnh 2.1 Cu trc phn cng ca nt cm bin....................................................................... 36Hnh 2.2 u cui RF............................................................................................................... 43Hnh 2.3 Tit kim nng lng v chi ph cho cc ch ng................................................ 49Hnh 2.4 Nng lng/hot ng vi di in p ng trn Intel StrongARM-1100 ................ 51Hnh 2.5 Hai m hnh khng tng thch vi h iu hnh WSN........................................... 56Hnh 2.6 M hnh lp trnh da trn s kin............................................................................ 57Hnh 2.7. Nt Mica ................................................................................................................... 60Hnh 2.8 Nt cm bin EYES................................................................................................... 61Hnh 2.9 Btnode ........................................................................................................................ 61Hnh 3.1 Ba loi b cha trong mt mng cm bin mt bc nhy n gin........................ 64

Hnh 3.2 Mng a bc nhy.................................................................................................. 65Hnh 3.3 Nhiu ngun/nhiu b cha...................................................................................... 67Hnh 3.4 B cha di ng dch chuyn qua mng cm bin.................................................... 67Hnh 3.5 Vng cc cm bin tm kim s kin........................................................................ 68Hnh 3.6. V d tp hp............................................................................................................ 72Hnh 3.7 Hai la chn giao din dch v vi ngn xp giao din........................................... 76Hnh 3.8 WSN vi nt cng vo ra, c th truy cp n itng xa qua Internet............. 78Hnh 3.9 Giao tip WSN Internet ......................................................................................... 79Hnh 3.10 Giao tip Internet-WSN .......................................................................................... 79Hnh 3.11 Kt ni gia hai WSN qua Internet........................................................................ 80Hnh 4.1 Ph in t - tn s v tuyn.................................................................................... 84Hnh 4.2 V d v ASK.......................................................................................................... 86Hnh 4.3 V d v PSK............................................................................................................. 87Hnh 4.4 V d v FSK............................................................................................................. 87Hnh 4.5 M t hin tng truyn sng.................................................................................... 88Hnh 4.6 Truyn sng a ng............................................................................................. 89Hnh 4.7 Tc li bit ca PSK v FSK nh phn c tch sng nht qun........................ 92Hnh 4.8 V d v tri ph dy trc tip................................................................................... 95Hnh 4.9 V d v ly mu v ng b.................................................................................... 97Hnh 5.1 Tnh hung u cui n (cc vng trn l di truyn dn v nhiu)....................... 103Hnh 5.2 Bt tay RTS/CTS trong IEEE 802.11...................................................................... 108

Hnh 5.3 Hai vn trong bt tay RTS/CTS.......................................................................... 108Hnh 5.4 S thc dy nh k............................................................................................ 111Hnh 5.5 Chu trnh lm vic STEM ca mt nt n............................................................. 112Hnh 5.6 Nguyn l S-MAC ................................................................................................... 113Hnh 5.7 Khung S-MAC v t NAV.................................................................................... 115Hnh 5.8 Giao thc thit b trung gian vi cc b ho gii khng rng buc......................... 116Hnh 5.9 Nhiu gia cc nhm............................................................................................... 121Hnh 5.10 T chc ca chu k LEACH................................................................................. 122Hnh 5.11 SMACS: ci t tuyn cho hai nt n................................................................. 123Hnh 5.12 Cc ng dng ca Zigbee...................................................................................... 125Hnh 5. 13 Cc kiu mng ca ZigBee................................................................................... 126

Hnh 5.14 Cu trc siu khung ca IEEE 802.15.4 ................................................................ 127Hnh 5.15 Bt tay gia b iu phi v thit b khi thit b tm kim gi tin......................... 129Hnh 6.1 Format ca mt khung lp vt l IEEE 802.11/802.11b ......................................... 133


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Hnh 6.2 nh dng gi tin DLL......................................................................................... 134Hnh 6.3 V tr ca FEC trong chui gi/nhn; thc hin m hov gii m FEC................ 138Hnh 6.4 Chi ph nng lng ca m Reed-Solomon vi kch thc khi v t lm khc nhau .......................................................................................................................... 140Hnh 6.5 Hot ng ca m chp........................................................................................... 141Hnh 6.6 Tiu th nng lng trong khi truyn 10 kB d liu qua tuyn vi suy hao ng

truyn 70 dB theo cc s m ho khc nhau..................................................................... 142Hnh 6.7 Nng lng s dng truyn thnh cng 1 bit d liu vi cc tkhc nhau ......... 144Hnh 6.8 Nng lng/bit hu dng cho d liu c kch thc u = 100 v u = 500 vi t l li

bit khc nhau ........................................................................................................................... 148Hnh 6.9 Nng lng/bit hu dng vi t l li bitpc nh vkch thc d liu uthay i.................................................................................................. 148Hnh 6.10 nh khung truyn thng vi header/d liu/kim tra tng so vi nh khung kiukim tra tng trung gian......................................................................................................... 151Hnh 6.11 Tiu th nng lng v tr mong i ca cc gi thng tin c kch thc khc nhau

L(theo byte) v cc t l li trng thi tt khc nhau. ............................................................ 153Hnh 6.12 ng cong biu th xc sut nhn tin cho cc gi tin c to ra t nt trung tm

vi hai cng sut khc nhau.................................................................................................... 154Hnh 6.13 T l nhn tin cc b thu c khong cch khc nhau.......................................... 155Hnh 6.14 M t vn c lng......................................................................................... 156Hnh 7.1 V d cho s phn chia ca mng........................................................................... 161Hnh 7.2 V d cho s phn chia ca mng........................................................................... 163Hnh 7.3 Xc sut sinh nht m kngoi 142n trm la chn cc a ch ngu nhin khngc cc xung t....................................................................................................................... 166Hnh 8.1 Xc nh gc ti ca mt s kin m thanh xa bng mt mng cc cm bin mthanh. ...................................................................................................................................... 174Hnh 8.2 Mt phn s ca hot ng trong ng b my pht/my thu........................... 182

Hnh 8.3 LTS a bc nhy phn tn..................................................................................... 185Hnh 8.4 S ng b my pht/my thu trong TPSN............................................................. 190Hnh 8.5 V d RBS: hai nt ivjv mt my phtR.......................................................... 192Hnh 8.6 Nhiu min qung b............................................................................................... 196Hnh 8.7 Tch hp gi tin, chuyn tip v bin i nhn thi gian....................................... 196Hnh 8.8 ng b thi gian: ng b trong mt min qung b n l................................. 199Hnh 9.1 Xc nh v tr ca cc nt cm bin vi s h tr t mt s cc im neo; khng

phi tt c cc nt l cn thit trong giao tip vi tt c cc nt neo..................................... 203Hnh 9.2 Php c tam gic bi ba vng trn giao nhau........................................................ 205Hnh 9.3 Bn cht ngu nhin ca vic nh x cc gi tr RSSI ti cc khong cch [25].... 206Hnh 9.4 Gc to bi hai nt neo............................................................................................ 208

Hnh 9.5 c lng khong cch Euclidean trong s vng mt ca kt ni trc tip [22]... 213Hnh 9.6 a bn lp: cc nt A, B, v C c th xc nh cc v tr ca n trong vi php lp(cc mi tn m ch cc ng ni m phm vi ca chng c s dng trong mt php lp cho).................................................................................................................................... 214Hnh 9.7 Cc kch bn cn phi bn cho a bn lp............................................................... 215Hnh 9.8 S x l theo xc sut cc v tr ca nt [25].......................................................... 216Hnh 10.1 Cu trc lin kt mng trong mt mng cm bin khng dy c trin khai vimt cao............................................................................................................................... 219Hnh 10.2 Cu trc lin kt mng tha hn sau khi gim cng sut pht.............................. 220Hnh 10.3 Gii hn cu trc lin kt mng bng cch s dng mt xng sng................... 220Hnh 10.4 S dng cc phn nhm chia mt s thnh cc phn.................................. 221

Hnh 10.5 Mc tiu ti u ha iu khin cu trc cu trc lin kt mng: xc sut ca mngc kt ni so vi kch thc trung bnh ca thnh phn cu thnh ln nht...................... 223


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Hnh 10.6 Cu trc ca RNG: vng ti phi khng cha cc nt no khc cho hai nt c ktni........................................................................................................................................... 227Hnh 10.7 Minh ha vng tip sng ca nt ivi nt r(vng ti ch th cc im ni m tipsng c hiu sut cao hn thay v truyn thng trc tip)...................................................... 228Hnh 10.8 Hai kch bn lm cch no xy dng cc nt ln cn cho nt ingoi cc vng tipsng vi cc nt khc............................................................................................................. 229

Hnh 10.9 Minh ha mt thut ton tp hp chi phi n gin da trn vic pht trin mt cy(cc ng nt m ch cc cnh trong cy, cc nt mu en to thnh tp hp chi phi. .... 231Hnh 10.10 S v d mt la chn khm ph tham vng da trn li ch mt bc btht bi.................................................................................................................................... 232Hnh 10.11 Cu trc tp hp chi phi tham vng vi v khng vi vic nhn v pha trc.233Hnh 10.12 Tnh n s cn thit kt ni hai nt mu en ph v mi quan h gia hai ntA v B. .................................................................................................................................... 234Hnh 10.13 S v d cho vic nh du cc nt vi cc nt ln cn khng c kt ni.236Hnh 10.14 Mt s v d vi mt tp hp c lp cc i................................................ 238Hnh 10.15 Tp hp c lp cc i to ra cc phn nhm chng nhau hoc khng chngnhau ........................................................................................................................................ 239

Hnh 10.16 Hai phn nhm c ni bi hai cng chnh phn tn........................................ 239Hnh 10.17 Thut ton c bn xc nh cc tp hp c lp, s dng cc s nhn dng ntnh xp hng (cc nt mu trng l cha c xc nh, cc nt mu en l cc ch huy phnnhm, cc nt mu xm l cc thnh vin phn nhm. .......................................................... 241


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DANH MC BNG BIU

Bng 2.1 Mt nng lng ca cc loi pin chnh v ph khc nhau................................... 47Bng 2.2 Mt s tham s v tiu th nng lng ca b thu pht (N/A: khng cho php) .... 54

Bng2.3 V d v mt s c tnh ca cc cm bin............................................................... 55Bng 4.1 Mt s di ISM.......................................................................................................... 84Bng 6.1 S lng d liu ktng ng vi s lng bit c th hiu chnh tkhc nhau trongkhi n=1023 bit i vi m BCH........................................................................................... 144Bng 7.1 Tp hp cc ton t................................................................................................ 169


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CC THUT NG VIT TT

Ch vit tt Ting Anh Ting Vit

ADC Analog/Digital Convert B bin i tng t/sANDA Ad hoc Network Design Algorithm Thut ton thit k mng Ad hc

API Application Programming Interface Giao din lp trnh ng dng

ARQ Automatic Repeat Request Yu cu lp li t ng

ASIC Application-Specific Integrated

Circuit

Mch tch hp chuyn dng

ASK Amplitude Shift Keying Kho dch bin

AWGN Additive White Gaussian Noise Tp m Gaussian cng sinh

BCH BoseChaudhuriHocquenghem M BCH

BER Bit-Error Rate T s li bit

BPSK Binary Phase Shift Keying Kho dch pha nh phn

BSC Binary Symmetric Channel Knh i xng nh phn

CCA Clear Channel Assessment Kim tra knh truyn c ri khng

CCK Complementary Code Keying iu ch kho m b

CDMA Code Division Multiple Access a truy cp phn chia theo m

CIR Carrier to Interference Ratio T s tn hiu/nhiu

CPU Central Processing Unit Khi x l trung tm

CRC Cyclic Redundancy Check Kim tra tnh d tun honCSMA Carrier Sense Multiple Access a truy cp cm nhn sng mang

CTS Clear To Send Chc chn gi

DAC Digital/Analog Converter B bin i s/tng t

DAD Duplicate Address Detection Pht hin a ch p

DBPSK Differential Binary Phase Shift

Keying

Kho dch pha nh phn vi sai

DCF Distributed Coordination Function Hm to phn b


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DHT Distributed Hash Table Bng bm phn b

DLL Data Link Layer Lp lin kt d liu

DPM Dynamic Power Managemen Qun l nng lng ng

DQPSK Differential Quaternary Phase ShiftKeying

Kho dch pha t phn vi sai

DSP Digital Signal Processor B x l tn hiu s

DSSS Direct Sequence Spread Spectrum Tri ph dy trc tip

DVS Dynamic Voltage Scaling Di in p ng

EEPROM Electrically Erasable Programmable

Read-Only Memory

B nh ch c lp trnh c xo bngin

EHF Extremely High Frequency Tn s cc cao

FDMA Frequency Division Multiple

Access

a truy cp phn chia theo tn s

FEC Forward Error Correction Hiu chnh phng li

FFD Full Function Device Thit b chc nng y

FFT Fast Fourier Transform Bin i Fourier nhanhFHSS Frequency Hopping Spread

Spectrum

Tri ph nhy tn

FIFO First In First Out Vo trc Ra trc

FPFA Field-Programmable Gate Array Mng cng logic kh trnh

FSK Frequency Shift Keying Kho dch tn

GPS Global Positioning System Hthng nh v ton cuGTS Guaranteed Time Slot Khe thi gian m bo

IEEE Institute of Electrical and

Electronics Engineers

Vin cng ngh k thut in -in t

IF Intermediate Frequency Tn s trung gian

ISI InterSymbol Interference Nhiu lin k hiu

ISM Industrial, Scientific, and Medical Cng nghip, khoa hc v y t


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LEACH Low-Energy Adaptive Clustering

Hierarchy

Phn cp nhm thch ng cng sutthp

LED Light-Emitting Diode Diode pht quang

LNA Low Noise Amplifier B khuch i tp m thp

LOS Line Of Sight ng nhn thng

MAC Medium Access Control iu khin truy cp mi trng

MANET Mobile Ad Hoc Network Mng ad hc di dng

MCDS Minimum Connected Dominating

Set

Tp hp chi phi c ni nh nht

MDS MultiDimensional Scaling Chia t l a chiu

MEMS MicroElectroMechanical System H thng vi c in t

MLE Maximum Likelihood Estimation Cc i ho kh nng c lngtham s

MPDU MAC-layer Protocol Data Unit Khi d liu giao thc lp MAC

NAT Network Address Translation Dch ach mng

NAV Network Allocation Vector Vector nh v mngNLOS Non Line Of Sight Khng c ng nhn thng

OOK On-Off-Keying Kho ng m

PAN Personal Area Network Mng c nhn

PA Power Amplifier B khuch i cng sut

PDA Personal Digital Assistant Thit b h tr c nhn k thut s

PHY Physical Layer Lp vt l

PPDU Physical-layer Protocol Data Unit Khi d liu giao thc lp vt l

PPM Pulse Position Modulation iu ch v tr xung

PSD Power Spectral Density Mt ph cng sut

PSK Phase Shift Keying Kho dch pha

QAM Quadrature Amplitude Modulation iu ch bin vung gc

QPSK Quaternary Phase Shift Keying Kho dch pha t phn


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QoS Quality of Service Cht lng ca dch v

RAM Random Access Memory B nh truy cp ngu nhin

RFD Reduced Function Device Thit b gii hn chc nng

RFID Radio Frequency Identifier B nhn dng tn s v tuyn

RF Radio Frequency Tn s v tuyn

GRT Geography RouTing protocol Giao thc nh tuyn a l

RISC Reduced Instruction Set Computer My tnh c b lnh rt gn

ROM Read-Only Memory B nh ch c

RSSI Received Signal Strength Indicator B ch th cng tn hiu nhn

RS ReedSolomon M ReedSolomon

RTS Request To Send Yu cu gi

SDMA Space Division Multiple Access a truy cpphn chia khng gian

SFD Start Frame Delimiter Bt u du tch khung

SINR Signal to Interference and Noise

Ratio

T s tn hiu/nhiu v tp m

SMACS Self-Organizing Medium Access

Control for Sensor Networks

iu khin truy cp mi trng t tchc ca cc mng cm bin

SNR Signal-to-Noise Ratio T s tn hiu/tp m

STEM Sparse Topology and Energy

Management

Giao thc cu hnh mng v vn qun l nng lng

TCP Transmission Control Protocol Giao thc iu khin truyn dn

TDMA Time Division Multiple Access a truy cp phn chia thi gian

TRAMA Traffic-Adaptive Medium Access Truy cp mi trng lu lng thchng

UTM Universal Transverse Mercator Cc v tr trong cc ta

UWB UltraWideBand Bng siu rng

VLF Very Low Frequency Tn s rt thp

WLAN Wireless Local Area Network Mng khng dy cc b


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WPAN Wireless Personal Area Network Mng khng dy c nhn

WRP Wireless Routing Protocol Giao thc nh tuyn khng dy

WSDL Web Service Description Language Ngn ng m t dch v Web

WSN Wireless Sensor Network Mng cm bin khng dy


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CHNG 1. GII THIU CHUNG

Mc ch ca chng

Cc ng dng phi c nh hnh v xy dng da trn cng ngh m n s dng.iu ny c bit ng vi mng cm bin khng dy v n c th c xy dng theo cccch khc nhau. Chng ny s trnh by khi nim ca mng cm bin khng dy v mt sng dng ca n. T cc v d trnh by s phn thnh cc loi hoc cc lp ng dng.Tip theo l nhng thch thc i vi cc ng dng ny v a ra l do ti sao cng ngh hinnay khng th tho mn nhng thch thc ny.

Phn cui ca chng l nhng nh gi v cc loi ng dng ny i vi mng cmbin khng dy v a ra nhng gi v gii php cng ngh cho chng, c phn cng v kthut mng.

1.1 C s h tng cho mng cm bin khng dy

Mt mng cm bin bao gm s lng ln cc nt cm bin c phn b c bn trongv bn cnh hin tng.V tr ca cc nt cm bin khng cn phi thit k hoc xc nhtrc. iu ny cho php phn b ngu nhin trong cc a hnh phc tp hoc cc hot ngtr gip thm ha. iu nycng c ngha l cc giao thc ca mng cm bin v cc thutton phi c kh nng t t chc. Mt c im quan trng khc ca cc mng cm bin lkh nng phi hp gia cc nt cm bin. Cc nt cm bin c gn mt b x l bn trong.Thay v gi i s liu th ti nt ch, chng s dng kh nng x l thc hin cc tnh

ton n gin v ch truyn s liu c x l theo yu cu.

Chn ng trong WSN rt kh khn docc c tnh ring phn bit camng ny vicc mng v tuyn khc nh cc mng ad-hoc hoc cc mng t bo. Trc ht, do s lngnt cm bin l kh ln nn khng th xy dng mt quy tc cho a ch ton cc khi trinkhai v phn iu khin cho vic thit lp ID l cao. V vy, cc giao thc da trn IP truynthng c th khng p dng c cho WSN. Th hai, khc vi cc mng thng tin ni chung,hu ht cc ng dng ca mng cm bin yu cu truyn s liu cm bin t nhiu ngun timt nt gc. Th ba, cc nt cm bin b hn ch v cng sut, kh nng x l v dung lng

nh. Th t, trong hu ht cc ng dng, cc nt trong WSN thng c v tr c nh. Tuynhin, trong mt s ng dng, cc nt cm bin c th c php di chuyn v thay i v tr(mc d vi di chuyn rt thp). Th nm, cc mng cm bin thng ph thuc vo ngdng. Th su, v tr ca cc nt cm bin ng vai tr quan trng v vic la chn s liuthng da vo v tr. Hin nay cha thch hp cho vic s dng cc phn cng ca h thngnh v ton cu (GPS) cho mc ch ny. Cc phng php xc nh v tr ca cc nt cm

bin thng da vo cng tn hiu t mt s im xc nh. Cui cng, s liu c lachn bi cc nt cm bin trong WSN thng da vo hin tng chung, do s c dtha. Cc giao thc chn ng phi khc phc c d tha ny s dng hiu qu

bng thng. Tm li, phng php chn ng trong WSN cn phi quan tm n cc ctnh ring ca WSN cng vi cc yu cu v ng dng v cu trc.

Nhn chung, cc thit b tnh ton u phi x l thng tin t cch thc n gin n


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phc tp. Trong nhiu ng dng, v d nh cc ng dng vn phng, cc thit b tnh ton nythng c s dng x l thng tin lin quan n con ngi, nh vy i tng yquan h gin tip vi mi trng vt l.

Trong mt lp ng dng khc, mi trng vt l li tp trung vo i tng. Tnh tonc s dng iu khin i tng thng qua cc qu trnh vy l. V d nh iu khiu

khin cc qu trnh ho hc trong nh my iu chnh nhit v p xut. y, qu trnhtnh ton s c kt hp vi iu khin v n c gi l nhngtrong mi trng. Khngging nh cc loi h thng trc kia, cc h thng nhng ny thng khng da vo stngtc vi con ngi v v th, n c mt s yu cu v mt k thut lm c vic .Trong cc h thng ln th n c quan h mt thit vi nhim v iu khin.

Cc h thng nhng c bit n v s dng trong mt thi gian di (trn thc t,trn 98% cc thit b tnh ton s dng nhng). Chng xut hin hng ngy, hng giquanh cuc sng ca chng ta v pht trin mt cch nhanh chng. Hu ht cc thit b gia

dng u s dng nhng, v d nh my git, my quay phim, in thoi Trong cc ngdng ny, h thng nhng da trn s tng tc vi con ngi.

Xu hng cng ngh ny khng ch xut hin trong cc thit b ln nh my git m ncn c thc hin trong cc thit b nh hn, thm ch trong c hng tp ho. Nhiu thit bkhc nhau s kt hp vi thng tin x l iu khin cc qu trnh vt l v tng tc vingi s dng. Cng ngh ny c a ra bi Marc Weiser. Bng cch tch hp tnh ton viu khin trong mt mi trng vt l, m hnh tng tc c bit n y l ngi ngi, ngi my v mymy v cui cng l ngi mi trng vt l. Tng tc vimi trng vy l s quan trng hn l ch lm vic vi cc s liu.

thc hin iu ny, yu cu ngoi vic tnh ton v iu khin l thng tin. Tt ccc ngun tin ny c th chuyn thng tin thnh v tr ca c cu chp hnh hoc ngi sdng v n c th kt hp li vi nhau to nn mt bc tranh chnh xc v mi trng thct khi c yu cu. i vi mt s ng dng, nh cc mng cm bin v c cu chp hnh, rtd xy dng h thng vi cc cng ngh mng hu tuyn c. Tuy nhin, vi mt s ngdng, c rt nhiu tr ngi thc hin iu ny nh gi thnh cao (ln n 200 USD/ 1 cm

bin). c bit l trong mt h thng c s thit b rt ln, chng ta c th hnh dung ra cs phc tp ca n, vn bo dng ng dy, dy dn cn tr s di chuyn ca i tng,

ngn khng cho cm bin/c cu chp hnh li gn i tng iu khin. Do , thng tin vtuyn gia cc thit b ny, trong nhiu ng dng, l mt yu cu tt yu.

Mt lp mng mi xut hin trong nhng nm gn y, l mng cm bin khngdy (WSN - Wireless Sensor Network). Mng ny bao gm nhng nt n c th tng tcvi mi trng bng cch cm bin v iu khin cc tham s vt l. Nhng nt ny cng tchon ton vi nhau hon thnh nhim v ca n v mt nt n khng th lm c g vchng s dng thng tin v tuyn thc hin iu ny. Cc nt thucmng ny t nht cngcha mt s php tnh, giao tip v tuyn v c chc nng cm bin hoc iu khin. Mc dthc cht mng ny bao gm cc c cu chp hnh nhng thut ng mng cm bin khng

dy li l tn gi ph bin. i khi n cn c gi l mng cm bin v c cu chp hnhkhng dy(wireless sensor and actuator network).


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WSN hu dng khi n dng h tr cho nhiu ng dng thc t khc nhau. Mng nytn ti nhiu thch thc trong qu trnh nghin cu v nhiu vn v mt cng ngh v n rt

phc tp. Do khng th c cch duy nht phn loi mt cch r rng cc WSN v cngkhng th tn ti mt gii php thc hin cc yu cu thit k. V d, trong rt nhiu ngdng ca WSN, cc nt n trong mng khng th d dng kt ni vi ngun cung cp m

phi da vo ngun pin gn trn n. Trong cc ng dng ny, vic s dng nng lng chiu qu l nhim v rt quan trng, sao cho n c th hot ng trong thi gian lu nht cth. Trong mt s ng dng khng c ngun cung cp th cc tham s khc li ng vai trquan trng hn, v d nh chnh xc ca kt qu nhn c. Kch thc v gi thnh camt nt n cng c xem xt n trong mt s ng dng. V mt kch thc, n phi nh nm trn ngun pin cn v mt gi thnh, n ph thuc trc tip vo cht lng cm

bin ca nt. Thng thng, chnh xc ca kt qu c th nhn c t cc nt n. Slng, gi thnh v chnh xc ca cc nt n c lin quan n nhau khi so snh mt hthng c nhiu nt cm bin vi mt mng tp trung. Nt t tin s cho chnh xc cao

hn. S dng nhiu cm bin n gin v gn vi hin tng cn nghin cu s to ra mtkin trc h thng va n gin, va s dng nng lng c hiu qu so vi mng phn b.Cch hiu su hn mng cm bin khng dy l hin thc ho n.

1.2 Mng cm bin khng dyv ng dng

c trng v cu hnh mng cm bin

Mt nt trong mng WSN thng thng bao gm 2 phn: phn cm bin (sensor) hociu khin v phn giao tip v tuyn (RF transceiver). Do s lng nt trong WSN l ln vkhng cn cc hot ng bo tr, nn yu cu thng thng i vi mt nt mng l gi thnh

thp (10 - 50 usd) v kch thc nh gn (din tch b mt vi n vi chc cm2

).Do gii hn v ngun nng lng cung cp (pin...), gi thnh v yu cu hot ng

trong mt thi gian di, nn vn tiu th nng lng l tiu ch thit k quan trng nhttrong mng cm bin:

- Lp vt l(physical layer) (s c trnh by trong chng 4) tng i n gin,gn nh do rng buc v kch thc v kh nng tnh ton ca nt. K thut iu ch tn hiusnh QPSK, FSK ci thin hiu sut b khuch i cng sut. Cc k thut m ha sasai phc tp nh Turbo Codes khng c s dng, k thut tri ph c s dng cithin SNR thit b thu v gim tc ng ca fading ca knh truyn...

- Lp MAC (s c trnh by trong chng 5): k thut a truy cp TDMA hocCSMA-CA hiu chnh vi mc ch gim nng lng tiu th.

WSN thng c trin khai trn mt phm vi rng, s lng nt mng ln v cphn b mt cch tng i ngu nhin, cc nt mng c th di chuyn lm thay i s mng... do vyWSN i hi mts mng (topology) linh ng (ad-hoc, mesh, star ...) vcc nt mng c kh nng t iu chnh, t cu hnh (auto-reconfigurable).

Trong mt s WSN thng dng (gim st, cm bin, mi trng ...) a ch ID cc ntchnh l v tr a l v gii thut nh tuyn da vo v tr a l ny gi l giao thc nh

tuyn a l(GRT - Geography RouTing protocol). i vi mng c s lng nt ln, s mng khng n nh ... GRT gip n gin ha gii thut tm ng, gim d liu bngnhtuyn(routing table) lu tr ti cc nt. GRT ph hp vi cc WSN c nh, tuy nhin i vi


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cc nt di ng (a ch ID node thay i) giao thc nh tuyn tr nn phc tp v khng nnh.

- Phn nhm:phn chia mng din rng (hng trm, hng ngn nt) thnh cc nhm n nh cu hnhmng, n gin ha gii thutnh tuyn, gim xung t(collission) khi truycp vo knh truyn nn gim c nng lng tiu th , n gin ha vic qun l mng v

cp pht a ch cho tng nt mng (theo nhm).Do gii hn kh nng tnh ton ca tng nt mng cng nh tit kim nng lng,

WSN thng s dng cc phng php tnh ton v x l tn hiu phi tp trung (gim ti chont gn ht nng lng) hoc gi dliu cn tnh ton cho cc trm gc(c kh nng x ltn hiu mnh v t rng buc v tiu th nng lng).

Khi cm bin khng dy tr thnh thng phm quen thuc trn th trng th vic lachn gia cc loi cm bin v kiu mng mi v c lm au u cc chuyn gia v lm choh phi xem xt li nhng chin lc xy dng kin trc mng m trc y tng b gt

sang mt bn. Sau y, chng ta cng tm hiu v 3 kiu mng c bn s dng cho cm binl kiu mng im - im(point to point), im - a im v mng a im a im.

Cu trc mng im im

L kiu kt ni n gin nht, hai nt truyn thng qua hai anten thu pht cng sut caohng trc tip vi nhau.Trn l thuyt, kiu mng ny l an ton nht v ch c 1 im trongmng c kh nng xy ra s c, l im mng ch hay cn gi l host. nng cao khnng ca h thng mng ch cn b sung thm 1 host d phng. Tuy nhin, vic ni dy 2host li l vn ng bn. Mt s cu trc mng ny h tr tn hiu iu bin tncho dy

dn truyn ti tn hiu ca nhiu cm bin trn cc knh FM ring bit. Mt s chun (nhHART bus) h tr ng truyn tn hiu s song cng cho nhng ng truyn tn hiu tngtsn c trong mt s nh my cng ngh c. Kiu kin trc nh vy xa nha danh giikhc bit gia cu trc mng imim v cu trc mng a im.

Nhng kiu mng khng dy u tin s dng tn hiu tn s radio (RF - RadioFrequency) n gin cho cu trc mng imim. Cu trc mng ny s dng modem RF 2 u mng. Mt ci t ti u pht lm nhim v chuyn tn hiu RS -232 thnh tn hiuradio v ci cn li t ti u thu lm nhim v chuyn tn hiu v trng thi vn d ca n.Fluke (Everett, Washington) pht trin mt loi vn k s c th nhn tn hiuin p v

truyn i qua mt knh tn s radio chuyn bit. Tuy nhin, cch ny b nghi ng v tincy v thit b ny c thit k cho nhng tn hiu FM m ha n gin. Cn trong mitrng nh my, cc yu t gy nhiu c th lm gim ng k cht lng ca tn hiu, do vymng tr nn khng ng tin cy, tr khi n c chm sc rt chu o.Kiu mng LAN khng dy cng c s dng trong cu trc mng ny nhng n ch t rahp vi mi trng vn phng hn l nh my. Nhng nh thit k s dng h thng thu thpd liu t xa kt hp vi cu trc mng ny bng cch dng b gom d liu v y d liuny ti b truyn tn hiu radio truyn ti host, ti y, tn hiu s c a tr v hnh hi

ban u vn c ca n.


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Hnh 1.1 Mng im im

im a im (Point-to-Multipoints)

Kt ni c chia s gia nt ti ln (Nt kt ni ti mng Internet thng qua ngtruyn hu tuyn cung cp kt ni Internet cho ton mng) dng anten a hng vi ccnt tixung(Nt kt ni ti mng v ckh nng phc v c kt ni hu tuyn v v tuyncho mng) hoc nt lp(Nt kt ni vo mng v khng dng phc v cc client ch ngvai tr l nt trung gian lp tn hiu) vi anten thu cng sut cao. Cu hnh mng ny d trinkhai hn cu hnh imim v khi thm mt thu bao mi ch cn lp t thm thit b tikhu vc thu bao ch khng phi lp ti nt ti ln. Tuy vy, cc trm thu phi nm trong

phm vi ph sng v c ng nhn thng vi trm pht sng gc. Cc vt cn nh cy ci,nh ca, i ni, ... s gp phn lm cu hnh mng li im aim hot ng khng

hiu qu.

Hnh 1.2 Mng im a im

a im a im (Multipoints to Multipoints)

Mi nt c vai tr khng ch l im truy nhp cho cc trm m cn lm nhim vchuyn tip d liu.

Cu hnh ny c tin cy mng cao nht do cc nt c s lin thng vi nhau, mt nt


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ch cn c kt ni vi mt nt bt k m khng cn phi c kt ni trc tip vi nt ti lnnh trong cu hnh im a im, l c th kt ni vi ton mng. Tuy nhin, i li giaothc tm ng ca mng s c phc tp cao hn.

Hnh 1.3 Mng a im a im

Yu cu ca mng cm bin khng dy l cng ngh ca n phi thun tin vi cc ngdng hin c v tht s mang li hiu qu. Ngoi s cn thit lphi xy dng mt mng gir, n gin trong lp trnh v mng, cc nt cm bin c tui th di, thnh phn bt buc v

ch yu pht trin cc ng dng trn thc t l kh nng cm nhn v thc hin ca cccm bin trong mng. i vi nhiu tham s vt l, cng ngh cm bin thch hp tn tic th c tch hp trong mt nt ca WSN. Cc tham s l nhit , m, nh snghng ngoi v nh sng nhn thy (k c nh sng pht ra t camera), m thanh, rung ng (vd nh pht hinri lon a chn), p sut, cc cm bin ho hc Thm ch n c th cmnhn c cc i tng phc tp hn nh chi trong vn tr c th c cm gic.

Cc c cu chp hnh khng th c iu khin mt cch trn vn bngmt nt camng cm bin khng dy. Thng thng, cc c cu chp hnh kim sot mt thit b c kh

nh mt a servo, hoc c th bt/tt mt s thit b in bng rle in nh bng n,micro hoc thit b tng t. Trn c s cc nt c cm bin v /hoc c cu chp hnh skt hp vi kh nng tnh tonv giao tip to ra nhiu ng dng khc nhau vi nhiu kiunt khc.

Cc ng dng cu tr thin tai:y l mt trong nhng ng dng c ch nhtca WSN. Hin tng thng gp nht l pht hin chy rng: cc nt cm bin c trang bnhit k v c th xc nh v tr ca n (theo h to tuyt i hoc tng i, tc v tr can so vi cc nt khc). Cc cm bin ny c th vo mt m chy, v d nh mt khurng v t mt chic my bay. Chng to ra mt bn nhit chung ca khu vc hoc

xc nh chu vi ca khu vc c nhit cao c th tip cn t bn ngoi. V d tng t lkim sot tai nn ti nh my ha cht.


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Mt s cc ng dng cu tr thin tai c im chung vi cc ng dng qun s, khi cccm bin c dng pht hin, v d, qun ch ch khng phi l chy rng. Trong ngdng nh vy, cm bin nn c gi thnh r c th dng mt ln v cn phi dng vi slng rt ln v yu cu thi gian tn ti khng qu cao.

Gim st mi trng v lp bn a dng sinh hc: Cc WSN c th c dng

gim st mi trng, v d nh cc cht nhim ha hc ti v tr rc. Lin quan mt thitvi vic gim st mi trng l s dng cc WSN bit s lng cc loi ng thc vtsngtrong mt mi trng.

u im chnh ca cc WSN y l cc cm bin khng phi gim st, hot ngtrong thi gian di, giao tip v tuyn c c th t gn i tng c quan st. Do cc cm

bin c th c cu to nh khng b l nn n ch hi lm phin cc ng thc vtc quan st m thi. Thng thng, yu cu v s lng cm bin cao hn yu cu v thigian hot ng ca n.

Cc ta nh thng minh: S lng ph nng lngca cc to nh gmmt lng lnnng lng do s dng m, thng gi, iu ha nhit (HVAC) khng hiu qu. S tthn nu gim st theo thi gian thc, c phn gii cao nhit , lung khng kh, m vcc thng s vt l khc trong to nh bng WSN. iu ny c th lm tng mt cch ng kmc thoi mi ca ngi dn v gim lng tiu th nng lng. Ci thin hiu sut nnglng v tng mc thun tin l nhng mc ch ca "ta nh thng minh" hng ti. Do, cc h thng hu tuyn hin nay nh BACnet, LonWorks, hoc KNX hoc ang ctrinkhai. Cc tiu chun ny cng bao gm vic pht trin thnh phn khng dy hoc kthp chng trong tiu chun.

Ngoi ra, cc nt cm bin nh vy c th c s dng theo di mc chu ng chc ca cc ta nh trong khu hot ng a chn mnh. Bng cch o cc thng s c hcnh ti un ca dm c th nhanh chng xc nh thng qua WSN l liu to nh c anton vo sau trn ng t mc d n sp sp? y l mt li th ng k cho nhn vincu h. Cc h thng tng t cng c th c p dng cho cc cy cu. Loi cm bin khcc dng tm ngi trong mt ta nh b sp v chuyn thng tin cho mt i cu h.

u im chnh y l lp bn cng tc ca cc thng s vt l. Ty thuc vo ngdng c bit, cm bin c th c trang b thm vo cc ta nh hin c (cho cc ng dng

loi HVAC) hoc phi c a vo ta nh sp xy dng.

Qun l thit b: qun l c nhiu hn cc thit b trong mt ta nh, cc WSNcng c mt lot cc ng dng c th. Mt v d n gin l vo khng cn cha kho nhng ni mi ngi eo ph hiu, n cho php WSN kim tra nhng ngi c php vocc khu vc . V d ny c th c m rng pht hin k xm nhp, v d nh khi

phng tin ca h ra khi c quan trong gi lm vic. Mt WSN din rng c th theo di vtr ca mt phng tin no v bo cho nhn vin an ninh. ng dng ny c nhiu imchung vi cc ng dng trong qun s. Theo cch khc, mt WSN c th c s dng trong

mt nh my ha cht kim tra r r ha cht. i km cc ng dng ny l cc yu cu ythch thc nh s lng cm bin c th ln, phi c tnh cng tc (nh trong v d theo di)v c th hot ng bng pin trong mt thi gian di.


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Bo dng v gim st my: Mt tng l c nh cc ntcm bin nhng ni tmy mc nhng kh tip cn, ni n c th pht hin cc chn ng v n cho thy s cnthit phi bo tr. Trng hp ny c th l cc robot hoc cc trc xe ca on tu. Cc ngdng khc trong sn xut nh my t nhng ni c phng x, cha nhiu cht c hi,hoc nm su di lng t... u im chnh ca cc WSN y l hot ng khng cn dy

ni nn khng cn phi bo dng, cc cm bin c gi thnh thp v c th thng xuync ci t li. Ngun cp bng dy dnth lc c, lc khng ph thuc vo tng ng dng.

Nu khng c ngun nui th vic cm bin phi hot ng trong mt tri gian di bngngun pin c nng lng hn ch l khng thc t v tn km. Th nhng kch thc v githnh ca cc nt thng khng phi l vn qu quan trng.

Trong nng nghip: p dng WSN vo nng nghip lm cho vic th phn v titiu c chnh xc bng cch t cc cm bin o m/ thnh phn t vo mi trng.Ch cn mt s lng tng i cm bin nh l , khong mt cm bin cho mi vng cdin tch 100 m 100 m. Tng t, gim st su b c th c thc hin bng mt b theo

di c phn gii cao. Ngoi ra, chn nui c th tng li nhun t vic gn cm bin chomi con ln hoc b kim sot tnh trng sc kho ca ng vt (bng cch kim tra nhit c th, m bc) v bo ng nu vt qu ngng cho php.

Chm sc sc khe v y t: Cng cch lm tng t, s dng WSN trong cc ngdng chm sc sc khe em li rt nhiu li nhun nhng cng gy tranh ci v mt oc. Phm vi p dng l t chm sc sau phu thut v chuyn su, ni m cm bin trc tipgn vo vi bnh nhn th hin li th so vi hu tuyn - gim st bnh nhn trong thigian di (thng l ngi cao tui) v qun l thuc t ng (cm bin nhng vo bao b

ca thuc, bt bo ng khi s dng sai cho bnh nhn). Do , cc h thng theo di bnhnhn v bc s trong bnh vin gip tit kim thi gian.

Thng tin: Cc cm bin nhng vo trong cc ng ph hay l ng c th thuthp thng tin v iu kin giao thng t a ra nhng gii php tt hn. Cc cm binny c th tng tc vi xe i trn ng cnh bo nguy him v cc iu kin ng haych tc giao thng pha trc.

Bn cnh , cc ng dng khc ca WSN h tr ct cnh cho my bay, trong cc nhmy x l nc thi, thit b o c ca phng x l cht bn dn v cc ng hm gi,

trong "nh tr thng minh" (ni c s tng tc gia chi v tr em), pht hin ca l lt,gim st mi trngsng ca chim trn mt hn o, v cm bin cy vo c th ngi (theo di lng ng hoc vng mc gi).

Hu ht cc ng dng ny u c th c thc hin theo mt cch no bng cngngh hin nay m khng cn cc mng cm bin khng dy. Nhng,cc ng dng s lm victt hn khi c nhiu thng tin hn v gii php khng gian v thi gian ca i tng cnquan tm so vi nhng g m cng ngh cm bin truyn thng c th c c. Cc mngcm bin khng dy c phm vi cung cp thng tin ln vi chnh xc yu cu ti cng thiim v c lng tiu th nng lng l t nht c th.

Mng cm bin c th s dng trong rt nhiu lnh vc. Nu phn loi da vo chcnng ca mng th c th hnh dung ng dng ca cc mng cm bin nh sau:


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- Cm bin mi trng (qun s: pht hin mn, cht c, dch chuyn qun ch...;cng nghip: h thng chiu sng, m, phnh chy, chng r r...; dn dng: h thng iuha nhit , chiu sng...).

-iu khin(qun s: kch hot thit b, v kh qun s ...; cng nghip: iu khin tng cc thit b, robot ...).

- Theo di, gim st, nh v (qun s: nh v, theo di sdch chuyn thit b, quni...).

-Mi trng(gim st l lt, bo, gi, ma ... pht hin nhim, cht thi...).

- Y t(nh v, theo di bnh nhn, h thng bo ng khn cp...).

-H thng giao thng thng minh: giao tip gia bin bo v phng tin giao thng,h thng iu tit lu thng cng cng, h thng bo hiu tai nn, kt xe ... h thng nh v

phng, tr gip iu khin t ng phng tin tin giao thng...

- Gia nh (nh thng minh: h thng cm bin, giao tip v iu khin cc thit bthng minh ...)

Hu ht cc ng dng ny c c tnh c bn ging nhau. Khc bit r rng gia ccngun d liu (nt cm bin) l mi lin h gia d liu o c b cha - v cc nt (nid liu c gi i). B cha c khi l mt phn ca chnh mng cm bin, nhng c khi nl cc h thng ngoi mng. Do , s ngun thng nhiu hn b cha (nhng khng philc no cng vy) v b cha khng bit hoc khng ch n vic nhn dng ngun. yd liu c vai tr quan trng hn nhiu.

M hnh tng tc gia ngun v b cha c th hin theo mt s cch sau:

Pht hin s kin: Cc nt cm bin phi bo co vi b cha khi n pht hin s xuthin ca s kin. Nhng s kin n gin nht c th c pht hin bi mt nt cm binn (v d nh vt qu ngng nhit ; loi s kin phc tp hn yu cu phi c s cngtc ca cc b cm bin ln cn hoc thm ch l cc cm bin xa quyt nh xem liu skin xy ra cha (v d nh ng bin thin nhit tr nn qu dc). Nu nhiu s kinkhc nhau xy ra th phi thc hin phn loi s kin.

Cc php o nh k: Cc cm bin c th c giao nhim v thu thp cc s liu o

c tnh nh k. Thng thng, d liu c c khi mt s kin pht hin c kch hot; chuk ca d liu ph thuc vo ng dng.

Chc nng xp x v pht hin bin: Cch gi tr vt l (v d nh nhit ) thay it ni ny sang ni khc c th c coi l chc nng ca a im. WSN c th c sdng xp x chc nng cha bit ny (ch xt cc c tnh khng gian ca n), bng cchs dng mt s gii hn cc mu ly ti mi nt cm bin ring bit. Bn xp x ny phi c thc hin b cha. Lm th no v khi no cp nht bn ny, chnh xc ca chcnng xp x v mc tiu th nng lng ph thuc vo nhu cu ca cc ng dng.

Tng t nh vy, vn lin quan l c th c tm thy cc khu vc hoc cc imc cng gi tr thu c. V d, tm nhng im thuc ng ng nhit khi chy rng


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pht hin bin gii ca m chy thc t. iu ny c th c tng qut tm ra "bin "trong cc chc nng nh vy hoc gi tin nhn dc theo ranh gii ca ccmu trong ckhng gian v /hoc thi gian.

Theo di: Ngun ca mt s kin c th di chuyn (v d khi theo di trm t nhp).WSN c th c s dng cp nht v tr, nh gi tc v hng ca ngun s kin n

b cha. lm nh vy, thng thng cc nt cm bin phi hp tc vi nhau trc khi cpnht d liu cho b cha.

Cc nt cm bin tng tc vi nhau c v thi gian v khng gian (bo co s kin chthc hin trong mt khong thi gian nht nh v ch t cc khu vc nht nh). Nhng yucu ny cng c th thay i mt cch linh hot theo thi gian; b cha phi thng bo chocc b cm ng yu cu ca chng trong qu trnh hot ng. Tng tc c th din ra chnhm phc v mt yu cu c th ca b cha, hoc phc v cho mi quan h lu di gia cc

b cm bin v b cha.

Cc v d cho thy s a dng trong cc la chn ng dng. C th c nh v trt cc nt cm bin (nh trong cc ng dng bo tr my mc thit b) hoc c th t ccnt cm bin mt cch ngu nhin bng cch th mt s lng ln cc nt t my bay vomt m chy rng. Ngoi ra, cc nt cm bin c th t di chuyn b p thiu st trongqu trnh trin khai v n v tr mi m ti , nhim v cm bin ca n thc hin c tthn. N c th di chuyn gim st thm cc i tng khc (trong cc ng dng hu cn)v mng thch ng vi n.

Cc ng dng cng nh hng n vic la chn bo dng: C nht thit phi bo

dng cc cm bin v cc my mc thit b c lin quan? Bo dng l khng ph hp vcc mng ny ch c trin khai trong mng ad hoc, theo cch thc ngn hn, b gii hn bithi gian thc hin ti a (nh trong cc hot ng khc phc thm ha)? Cc cm bin nyc chc nng khng gim st trong mt thi gian di nn khng ckh nng bo tr?

Trong mt s ng dng, ngun cp hu tuyn c th thc hin c v y khng cvn g v cung cp nng lng. i vi cc nt cm bin t hot ng, ty thuc vo yucu v thi gian thc hin m nng lng cung cp c th khng ng k (vi nhng ngdng yu cu thi gian thc hin l mt vi ngy) hoc s l vn i vi cc ng dngkhng th bo dng m yu cu thi gian thc hin l vi nm. R rng l gi c v kch

thc mi nt ng mt vai tr quan trng trong vic thit k cung cp nng lng.

1.3 Nhng kh khn ca mng cm bin khng dy

X l mt lot cc loi ng dng nh trn s gy kh khn cho mng cm bin. Tuynhin, vn c c im chung cho cc ng dng nh vy, c bit l trn kha cnh c tnhv cc k thut yu cu. Hin thc ho cc c tnh ny bng k thut mi l kh khn chnhi vi mng cm bin khng dy.

1.3.1 Cc yu cu k thut

Cc c tnh sau c yu cu trong hu ht cc ng dng ca mng cm bin khngdy:


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Loi hnh dch v: Chc nng ca mng thng tin thng thng hin nhin l dichuyn cc bit t ni ny n ni khc. i vi mt WSN, di chuyn cc bit ch l bc ktthc, nhng khng phi l mc ch thc t. Hn th na, mt WSN c k vng l cungcp thng tin c ngha v/ hoc hnh ng theo nhim v cho. Ngoi ra, cc khi nim

phm vi tng tc, khu vc a l c trng hay khong thi gian s tr nn quan trng. Do

yu cu phi c mt m hnh mng mi vi cc giao din mi v cch ngh mi v dch vmng.

Cht lng dch v: Lin quan cht ch n cc loi hnh dch v mng l cht lngdch v. Thng thng, cht lng ca dch v th hin trong cc ng dng thuc loi hnh a

phng tin. Tr b chn hoc bng thng ti thiu khng thch hp cho cc ng dng c trhoc khi bng thng ca d liu truyn i rt nh. Trong mt s t trng hp, vic cung cpcc gi d liu c th tha, trong nhng trng hp khc, yu cu tin cy rt cao. Nhngtrng hp nh vy s lm tng vai tr ca tr khi cc ccu chp hnh c iu khin theothi gian thc bi mng cm bin. Cht lng dch v ch cn c vo h s cung cp gi tin l

cha y v n cn lin quan n s lng v cht lng thng tin v i tng hoc khuvc c quan st.

Mc chu li: Do cc nt c th ht nng lng hoc b hng, hoc thng tin v tuyngia hai nt b gin on nn WSN c th c li. Trong nhng trng hp nh vy, hnch li th WSN nn c s nt nhiu hn mc cn thit.

Thi gian s dng: Trong nhiu trng hp, cc nt phi da vo ngun nng lnghn ch (s dng pin). Vic thay th ngun pin ny l khng thc t v khng th thc hintc thi. WSN phi s dng c t nht l trong thi gian thc hin nhim v c giao. Do

, tui th ca WSN rt quan trng v hin nhin, cch thc WSN s dng nng lngmt cch c hiu qu thc s cn thit.

thay i hoc b sung thm nng lng cho WSN, ngun c cng sut hn ch (vd nh pin mt tri) cng c th c s dng cho cc nt cm bin. Thng thng, ccngun ny khng mnh m bo cho hot ng c din ra lin tc nhng n c thdng xc pin. Vi cch lm nh vy th tui th ca WSN, theo l thuyt, s l v hn.

Tui th ca WSN t l nghch vi cht lng dch v: s dng nhiu nng lng s lmtng cht lng dch v nhng nh vy s lm gim tui th ca mng. Chnh v vy, khi thit

k mt WSN phi cn bng hai yu t ny.

nh ngha chnh xc tui th ph thuc vo ng dng c th ca mng. l khongthi gian t khi mng bt u s dng cho n khi nt u tin b hng (hoc ht nng lng);hoc n bao gm khong thi gian t khi mng bt u s dng cho n khi mt kt ni giahai hoc nhiu nt v khong thi gian cho n khi 50% nt b hng; hoc l khong thigian khi ln u tin mt im nm trong vng quan st khng cn chu s gim st ca btk nt cm bin no (trong nhiu trng hp, WSN s dng s nt cm bin nhiu hn yucu nn mt im c th chu s gim st ca nhiu nt).

Kh nng m rng: T mt WSN gm mt s lng ln cc nt, kin trc v giaothc ca mng lm vic c kh nng m rng.


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Di rng ca mt : Trong mt WSN, s lng nt trn mi n v din tch - mt ca mng - c th khc nhau ng k. Cc ng dng khc nhau s c mt nt rt khcnhau. Ngay c trong mt ng dng nht nh, mt c th khc nhau theo thi gian vkhng gian do cc nt di chuyn hoc b hng; mt cng khng phi ng nht trong ton

b mng (do v tr t nt khng hon ho) v mng nn thch ng vi cc bin i .

Kh trnh: khng ch cn cho cc nt x l thng tin m cn n cn dng ccnt phn ng linh hot hn khi thay i nhim v. Cc nt cn c lp trnh, v chng trnh phi c thay i trong qu trnh hot ng, khi nhim v mi trnn quan trng. X ll thng tin theo mt cch nh sn khng th p ng c yu cu.

C kh nng bo dng: Khi c mi trng ca WSN v chnh bn thn WSN thayi (ht pin, nt b hng, khi c nhim v mi) th h thng phi thch nghi vi iu .N cththeo di trng thi ca chnh mnh thay i cc thng s hoc la chn tiu ch hotng (v d nh cht lng dch v s b gim st khi ngun nng lng b yu i). Trong

trng hp ny, mng phi t bo dng, n cng c th tng tc vi cc c ch bo dngbn ngoi qu trnh hot ng m bo cht lng t ra.

1.3.2 Cc k thut yu cu

thc hin cc yu cu ny, k thut i mi mng thng tin, kin trc v cc khinim giao thc mi c thc hin. Thch thc y l cn phi tm cng ngh p ngc cc yu cu v cht lng dch v, tui th v cc yu cu v kh nng bo dng. Mtkhc, cng ngh ny phi s dng c trong nhiu ng dng c th v phi cho thy ctnh cn thit ca WSN trong cc ng dng ny. Sau y l mt s cng ngh thng c

dng trong cc WSN:Giao tip v tuyn a bc nhy: Khi giao tip v tuyn l k thut ct li, thng tin

trc tip gia ngi gi v ngi nhn s phi i mt vi mt s hn ch. c bit, giao tipng di ch thc hin c khi s dng cng sut pht rt cao. Vic s dng cc nt trunggian nh cc tr c th lm gim tng nng lng yu cu. Do , vi nhiu loi WSN, cigi l giao tip a bc nhyl mt thnh phn cn thit.

S dng nng lng c hiu qu: ko di tui th th vic s dng nng lng mtcch c hiu qu l k thut trng im. iu ny c th c c bng cch s dng hiu qu

nng lng truyn d liu gia hai nt (o bng bit /J) hoc quan trng hn l xc nh hiuqu nng lngca thng tin yu cu. Ngoi ra, tiu th nng lng khng ng u tonn cc "im nng - hotspot" cng l mt vn .

T cu hnh: WSN s phi t cu hnh cc thng s hot ng ca n, vic ny c lpvi cu hnh bn ngoi S nt cng t cngtt v b tr n gin l yu cu trong hu htcc ng dng. V d, cc nt c th xc nh v tr a l ca n ch bng cch s dng cc ntkhc trong mng. N cn c gi l "t nh v - self-location". Ngoi ra, mng c th ccc nt hng (v d nh do ht pin) hoc tch hp cc nt mi (v d nh b sung thm ntkhi mng cha p ng c yu cu t ra).

S cng tc v x l trong mng: Trong mt s trng hp, mt cm bin khng thquyt nh c vic liu s kin c xy ra hay khng nhng nhiu cm bin cng tc vi


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nhau s cung cp thng tin lm iu . Thng tin c x l trong mng theo cc cchthc khc nhau c c s cng tc ny. iu ny ngc vi vic mi nt truyn d liun mt mng bn ngoi x l.

V d, xc nh nhit cao nht v nhit trung bnh trong mt khu vc v agi tr n b cha. gii quyt bi ton ny mt cch c hiu qu, cc kt qu c t cc

cm bin ring l c tp hp li v truyn qua mng. Vic ny s lm gim s d liutruyn trn mng v do , vic s dng nng lng s hiu qu hn.

Trung tm d liu: Mng thng tin truyn thng thng tp trung vo vic chuyngiao d liu gia hai thit b c th, mi thit b yu cu c t nht mt a ch mng. Mng ckin trc nhvy hot ng theo trung tm a ch. Trong WSN, ni m cc nt thng c

b tr d d phng cho vic nt b hng hoc tng cht lng ca thit b ch c mt ntcm bin. Vic cung cp d liu ging nhau cho cng mt nt mng l khng cn thit. Vn quan trng y l bn thn d liu nhn c ch khng phi l nt cung cp d liu

. Do , xu hng hin nay l chuyn t m hnh trung tm a ch sang m hnh trung tmd liu trong vic thit k kin trc v giao thc truyn thng.

V d, m hnh tng tc ca trung tm d liu nh vy s c s dng khi cn cnhit trung bnh trong mt khu vc cho, n ngc vi yu cu nhit c t cc ntring l. M hnh trung tm d liu nh vy cng c th c dng t iu kin ch o cccnh bo hoc cc s kin ("bt bo ng nu nhit vt qu ngng").

1.4 Ti sao mng cmbin li khc vi cc mng khc?

Trn c s ca mt s ng dng v nhng thch thc chnh, mng cm bin khng dy

c th tr thnh mng Ad hoc di ng (MANETMobile Ad hoc Network) v fieldbus.

1..4.1 Mng Ad hc di ng v WSN

Mng Ad hoc l mt mng ci t, theo ngha en, cho mt mc ch c th, p ngnhu cu thng tin xut hin tc thi. V d n gin ca mt mng Ad hoc l mt tp hp ccmy tnh kt ni vi nhau qua cp to thnh mt mng nh, nh mt s my tnh xch taytrong mt phng hp. Trong v d ny, kha cnh t cu hnh ng vai tr quan trng - mngd kin lm vic m khng cn qun l hoc cu hnh bng tay.

Mng ad hoc

Ad hoc networks l im bin cui cng ca thng tin khng dy (thng tin v tuyn).Cng ngh ny cho php cc nt (im ni) mng truyn trc tip vi nhau s dng b thu

pht khng dy (wireless transceiver) m khng cn bt c mt c s h tng c nh no.y l mt c tnh ring bit ca mng ad hoc so vi cc mng khng dy truyn thng nhcc mng chia (cellular networks) v mng WLAN, trong cc nt (v d nh cc thu

bao in thoi di ng) giao tip vi nhau thng qua cc trm v tuyn c s (wired radioantenna).

Ad hoc networks c mong i s lm cch mng ha thng tin khng dy trong mtvi nm ti bng vic b sung thm vo cc m hnh mng truyn thng (nh Internet,cellular networks, truyn thng v tinh). Mng Ad hoc cng c th c xem nh nhng bn


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sao cng ngh ca nhng khi nim my tnh thng gp. Bng vic khm ph cng nghmng khng dy Ad hoc, nhng thit b cm tay chng loi (nh in thoi di ng, PDAs,my tnh xch tay, my nhn tin pager..) v cc thit bc nh (nh cc trm v tuync s, cc im truy cp Internet khng dy, ) c th c kt ni vi nhau, to thnh mngton cu, khp mi ni.

Trong tng lai, cng ngh mng Ad hoc c th s l la chn rt hu ch. V d, hyxem tnh hung sau. Mt cn ng t khng khip tn ph thnh ph ca chng ta, trong c hu ht cc c s h tng vin thng (nh cc ng in thoi, trm v tuyn c s).

Nhiu i cu h (nh lnh cu ha, cnh st, bc s, cc tnh nguyn vin ) ang n lc cu mi ngi khi cn ng t v cha tr cho nhng ngi b thng. h tr tt hncho i cu h, cc hot ng cu h ca h phi c hp tc vi nhau. R rng l 1 hotng hp tc nh th ch t c thnh qu khi i cu h c th giao tip, thng tin vinhau, c vi ng nghip ca mnh (v d 1 cnh st vi 1 cnh st khc) v c vi thnh vinca i cu h khc (v d 1 lnh cu ha yu cu s tr gip t 1 bc s).

Hnh 1.4 S nguyn l mng chia s kt ni dng ad hoc

Vi nhng cng ngh hin c, nhng n lc ca i cu h s rt kh thnh cng khinhng c s h tng vin thng c nh b tn ph nng n. Thm ch nhng thnh vin cai cu h ny c trang b PDA hay cc thit b tng t khc trong trng hp khng thtruy cp c vi cc im c nh, ch nhng kt ni gia cc thnh vin ca i cu hng gn nhau mi thc hin c. V vy, mt trong nhng u tin trong vic qun l vkhng ch thm ha ngy nay l ci t li cc c s h tng vin thng nhanh nht cth,

bng cch sa cha cc thit b, kt cu h hng hay trin khai cc thit b vin thng tmthi.

Kh khn ny c th c gii quyt ng k nu chng ta p dng nhng cng ngh

da vo mng Ad hoc: s dng cc giao tip khng dy phn tn gia nhiu im truy cpkhc nhau, thm ch cc i cu h cch xa nhau cng c th lin lc vi nhau hay lin lcvi cc thnh vin i cu h khc khong gia nh hot ng ca mt trm chuyn tip.


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V khu vc xy ra thm ha s tp trung nhiu i cu h, nn cc lin lc trong phm vithnh ph (hay thm ch l phm vi c nc) c th thc hin c, cho php cc n lc cuh c hp tc thnh cng m khng cn thit lp li cc c s vin thng c nh.

Thng thng, khi nim v MANET lin quan n truyn thng v tuyn v c bit ltruyn thng a bc nhyv tuyn. S di chuyn ca cc nt l mt thnh phn ca mng.

Cc mng ny c s dng cho hot ng cu tr thin tai - nhn vin cu ha giao tip vinhau - hoc dng trong cc a im kh khn nh cng trnh xy dng ln, ni c th victrin khai c s h tng khng dy (v d nh im truy cp) trong khi thc hin hu tuynkhng phi l mt la chn kh thi. Trong mng , cc nt ring l kt hp vi nhau tothnh mt mng chuyn tip cc gi tin gia cc nt, do n m rng phm vi hot ngca mt nt n, m rng khu vc a l gia ngi gi v ngi nhn. Hai thch thc c

bn ca MANET l t chc li mng khi cc nt di chuyn v x l cc vn v hn ch catruyn thng v tuyn.

y l nhng tn ti chung ca c mng MANET v WSN. Tuy nhin vn tn ti mts khc bit c bn gia hai mng ny m bo s phn bit gia chng.

Thit b v cc ng dng: ng dng v thit b ca MANET khc WSN. TrongMANET, u cui c th kh mnh (mt my tnh xch tay hoc mt PDA(Personal DigitalAssistant - Thit b h tr c nhn k thut s)) c ngun pin tng i ln. Cn c thit bny v trong cc ng dng MANET in hnh thng c s xut hin ca con ngi: MANETc s dng cho truyn thng thoi gia hai ng nghip xa, hoc c s dng truycp vo mt c s h tng t xa, ging nh mt my ch Web. V vy, thit b phi c mnh h tr cc ng dng ny.

Nh s dng mt lng ln cc nt cm bin, s dng cng ngh tnh ton v truynthng m WSN c th thc hin c rt nhiu ng dng khc nhau. iu khng c nghal ch s dng mt gii php m gii quyt c mi yu cu t ra. V d, WSN c th hiuc rt nhiu mt mng khc nhau, t tha tht dy c, v vy m n s yu cu nhiugiao thc khc nhau hoc t nht phi l cc giao thc ph hp. S a dng v mt khng

phi l iu ph bin trong cc MANET.

Tng tc vi mi trng: Do cc WSN phi c tng tc vi mi trng nn ctnh lu lng ca n c th rt khc nhau. Thng thng, cc WSN c tc tc d liu rt

thp mt thi gian di nhng n li c lu lng rt cao khi c hin tng xy ra (v d, ivi mt h thng thi gian thc l ma hoc bo). Trng thi ngh trong mt thi gian di cth thay th bng trng thi hot ng rt cao ca mng trong mt thi gian ngn, nng cngsut ca mng ln gii hn. Trong khi , MANET c s dng h tr nhiu ng dngthng thng hn (Web, ging ni) vi cc c tnh lu lng khng c s thay i t

bin.

Quy m: Cc WSN thng dng gim st s lng thc th ln hn nhiu (hngnghn, thm ch hng trm nghn) so vi mng ad hoc.

Nng lng: Trong c hai mng WSN v MANET, nng lng l vn c quantm. Cc WSN c yu cu cht ch hn v thi gian s dng, kh nng xc pin hoc thay thngun pin ca nt so vi MANET. Do , WSN quan tm nhiu n vic tiu th nng lng


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hn MANET.

T cu hnh: Tng t nh mng ad hoc, cc WSN yu cu t cu hnh thnh mng ktni,nhng s khc bit trong lu lng, s dng nng lng c th i hi gii php khcnhau. Tuy nhin, v mt ny th MANET v WSN tng t nhau.

tin cy v cht lng dch v: Cc yu cu lin quan n tin cy v cht lngdch v l kh khc nhau. Trong mt MANET, mi nt ring r u phi c tin cy khcao, cn trong mt WSN, mt nt ring r khng ng vai tr quan trng. Cht lng dch vca Manet c quyt nh bi cc ng dng truyn thng; i vi WSN, khi nim chtlng dch v lyu cu hon ton mi, v ng nhin, mng s phi s dng nng lng thc hin yu cu ny.

Trung tm d liu: Vic trin khai d phng cc nt s lm tng kch thc ca ccgiao thc trung tm d liu trong WSN. Cc giao thc trung tm d liu khng lin quan nMANET.

Dch chuyn: Vn dch chuyn trong MANET bao gm s dch chuyn cc nt dichuyn, thay i tuyn ng a bc nhytrong mng v iu ny phi c x l. Trongmt WSN, vn ny cng c th tn ti nu cc nt cm bin di chuyn. Trong WSN, c haivn v dch chuyn cn c quan tm.

Th nht, mng cm bin c th c dng pht hin v quan st mt hin tng vtl (v d nh trong cc chng trnh pht hin xm nhp). Hin tng ny l nguyn nhn cas kin xy ratrong mng (bt bo ng) v cng c th to ra mt s x l cc b (v d, xcnh xem c thc s c phi l mt k xm nhp?). iu g xy ra nu i tng di

chuyn? V mt l tng, d liu ti mt a im c tp hp li v c th s dng cho aim gn . Ngoi ra, trong cc ng dng theo di, y l nhim v ng nhin ca mng m bo mt s hnh thc hot ng xy ra trong cc nt xung quanh hin tng quan st.

Th hai, cc b cha thng tin trong mng (cc nt m thng tin phi c gi n)cng c th di chuyn. V nguyn tc, iu ny l khng khc vi vic di chuyn ca cc nttrong MANET thng thng, nhng c th lm gim hiu qu hot ng ca cc giao thc sovi trng thi tnh.

Hn na, trong MANET v WSN, tnh di ng cth tng quan vi nhau, tc l c

mt nhm cc nt cng di chuyn. V d nh trong MANET l mt nhm ngi i du lchcng nhau. Trong WSN, s chuyn ng ca cc nt c th bo cun i.

Tm li, tuy c nhng im chung nhng trn thc t, WSN h tr chocc ng dng rtkhc nhau, chng tng tc vi mi trng vt l v phi xem xt tht cn thn mc u tinca cc thng s. iu ny thc s lm nn s khc bit gia WSN v MANET.

1.4.2 F ieldbus and WSN

Fieldbus l mng c thit k c bit cho cc hot ng theo thi gian thc v thngvi dung sai li nh sn. N c s dng ch yu trong cc ng dng iu khin c xemnh l mt phn ca vng iu khin. V d nh Profibus v mng Token Bus IEEE 802.4cho t ng ha nh my hoc bus CAN cho cc mng onboard trong xe hi Do cc yu


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cu v thi gian thc rt nghim ngt nn cc mng ny thng l mng hu tuyn v ch ccc lp mt (lp vt l), hai (lp lin kt), v by (lp ng dng) ca m hnh chun OSIc s dng. Trnh giao tip qua nhiu bc v tr khi i qua cc nt trung gian. Mc dvy, mt s nghin cu vn lit k fieldbus vo loi truyn thng v tuyn.

Do fieldbus cng quan tm n mi trng vt l m n thu thp d liu cm bin t

a ra cc quyt nh iu khin nn vi ngha ny, n rt ging vi cc WSN. Theo mtcch hiu no th WSN c th c xem nh fieldbus v tuyn. Tuy nhin vn cn mt skhc bit: WSN khng ch n vn thi gian thc m n tp trung nhiu hn vo ccng dng c th chu c tr. Ngoi ra, vic la chn cc c tnh mt cch ph hp l ium WSN mun thc hin (v d nh tnh chnh xc i vi hiu qu nng lng), v iu nyli khng thng hin din trong fieldbus. Fieldbuses khng n lc bo tn nng lng, vcc giao thc ca n khng c chun b lm iu .

1.5 Cc k thut cho WSN

Xy dng cc mng cm bin khng dy ch tr thnh hin thc vi mt s tin b cbn trong cng ngh cho php. Trc ht, l cng ngh ti thiu ho phn cng. Kchthc ca chip cng nh th mc tiu th in nng cng t, thm ch nm trong kh nng tnhton ca WSN. iu ny lin quan c bit n vi iu khin v chip b nh, nhng ccmodem v tuyn, chu trch nhim v phn giao tip v tuyn, s lm cho vic s dng nn glng c hiu qu hn. Gim kch thc ca chip v hiu qu nng lng ci thin i km vichi ph gim, iu ny l cn thit thc hin trin khai d phng cc nt mt cch hp l.

Sau vic thu thp v x l thng tin th thit b cm nhn thc t l cng ngh quan

tm th ba. Rt kh bao qut vn ny v c rt nhiu loi cm bin khc nhau.Chng 2 s trnh by chi tit hn vn ny.

Ba phn c bn ny ca nt cm bin phi i cng vi ngun cp. Cc yu cu ny phthuc vo ng dng, pin c dung lng cao th tui th di. Mt cch l tng, nt cm bincng c thit b tm nng lng, np pin bng nng lng ly t mi trng - cc t bonng lng mt tri l mt la chn.

Tng ng vi cc cng ngh phn cng c bn l phn mm. Cu hi u tin trli y l s phn chia nhim v v chc nng trong mt nt n - kin trc ca h iu

hnh hay mi trng hot ng. Mi trng ny phi h tr vic thc hin li nhim v ngin, trao i thng tin lin lp v c module cho php thc hin cc bo dng n gin.Kin trc phn mm trn nt n phi c m rng n kin trc ca mng, ni thc hinvic phn chia nhim v gia cc nt.


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CU HI N TP CHNG 1

1.Nu by c im c bn ca WSN

2. Cc yu cu k thut ca WSN

3. Cc k thut yu cu ca WSN4. So snh mng Ad hoc v WSN

4. So snh Fieldbus v WSN

5. Nu mt s ng dng ca WSN trong cuc sng hng ngy

7. Nu c trng v cu hnh WSN


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CHNG 2. KIN TRC NT N

Mc ch ca chng

Chng ny gii thch phn t c bn ca WSN l nt, cc nhim v c bn ca n nhtnh ton, lu tr, giao tip, cm nhn/vn hnh v cc b phn c yu cu thc hin ccnhim v ny. Khi , tiu th nng lng ca cc b phn ny cng c cp n: nnglng c th lu tr, thu thp t mi trng v lu gi n bng cch iu khin ch hotng ca cc b phn ca nt mt cch thng minh. Vic iu khin ny do mt h iu hnhging nh mi trng thc hin quyt nh.

Cui chng, bn c s c nhng hiu bit nht nh v kh nng v nhng hn chca cc nt trong mng cm bin. N l nn tng ca cc chng sau, trong tp trung vocc nguyn tc la chn nt cm bin ring r c th kt ni thnh mt WSN.

xy dng mt WSN, yu cu u tin l cc nt hpthnh phi c trin khai vc th s dng. Cc nt ny phi c cc yu cu t cc yu cu ca ng dng cho: nh, rhoc hiu qu nng lng, c trang b cc cm bin tt, c kh nng tnh ton v ti nguyn

b nh cn thit, phi thch hp vi cc phng tin truyn thng. Cc b phn phn cngny v cu to ca chng trong nt chc nng c cp trong phn 2.1; cng sut tiu thca cc b phn ny v cc tho hip c ni n trong phn 2.2. Trong khi chng ny chtp trung v nt ring l th vic la chn k thut giao tip c bit cho kin trc ca mngcm bin khng dy li c m t trong chng 3.

Ngoi phn cng ca cc nt cm bin, h iu hnh v m hnh lp trnh cng l ccmi quan tm. Phn 2.3 m t nhim v ca h iu hnh, mt s v d v cc giao din lptrnh ph hp.

2.1 Cc b phn phn cng

2.1.1 Tng quan phn cng ca nt cm bin

Khi chn cc b phn phn cng cho nt cm bin khng dy, r rng l cc yu cuca ng dng ng vai tr quyt nh vi mi quan tm ch yu v kch thc, gi thnh vtiu th nng lng ca cc nt giao tip v cc phng tin tnh ton thng c quan

tm c cht lng chp nhn c, nhng tho hip gia cc c im v chi ph phi lct yu. Trong mt s trng hp cbit, ton b nt cm bin phi nh hn 1 cc, nh hn

100 g, r hn 1 USD v s dng t hn 100 W, thm ch c nhng trng hp kch thc thugn ch bng ht bi. Trong nhiu ng dng thc t, kch thc ca nt nh khng quan trngm s thun tin, ngun cp n gin v chi ph ng vai tr quan trng hn.

Tuy a dng nh vy nhng xu hng chung vn l tp trung vo nn tng phn cngca cc nt cm bin khng dy. Trong khi ng nhin l khng tn ti sn mt chun sdng cng nh khng tn ti chun c th h tr cho tt c cc loi ng dng nn phn ny s

a ra ci nhn tng qut v cc kin trc nt cm bin in hnh. Ngoi ra cn c mt snghin cu tp trung vo vic rt ngn cc b phn v mt kch thc, tiu th nng lnghay gi thnh.


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Mt nt cm bin c bn gm 5 b phn chnh (hnh 2.1):

B iu khin:B iu khin x l tt c d liu c lin quan theo m nh phn.

B nh:Thng thng, b nh c dng lu gi chng trnh v d liu.

Cm bin v c cu chp hnh:y lgiao din vi mi trng vt l. Cc thit b

ny c th quan st hoc gim st cc thng s vt l ca mi trng.

Thit b lin lc:Cc nt trong mng i hi mt thit b gi v nhn thng tin quaknh v tuyn.

Hnh 2.1 Cu trc phn cng ca nt cm bin

Ngun cp:Thng thng, khng c sn ngun cp in nn cn phi c pin cung

cp nng lng, thm ch c pin c th xc t mi trng (pin mt tri).

Mi b phn ny phi hot ng sao cho m bo lng tiu th nng lng l t nht c th, ng thi phi hon thnh tt c cc nhim v t ra. V d, c hai thit b lin lc v

b iu khin nn c tt cng lu cng tt. Mun thc dy(wakeup), b iu khin c ths dng mt b m thi gian c lp trnh trc kch hot li. Ngoi ra, cc cm bin cth c lp trnh tongt khi mt s kin c xy ra v d nh khi gi tr nhit vtqu mt ngng nht nh hoc thit b giao tip pht hin c thng tin n.

h tr chc nng cnh bo nh vy, yu cu phi c kt ni ph hp gia cc b

phn ring r. Hn na, c thng tin d liu v iu khin u phi c trao i qua cc ktni ny. Kt ni ny c th rt n gin, v d, mt cm bin c th gi gi tr tng t n biu khin; hoc phc tp hn l tin x l d liu cm bin v ch nh thc b iu khinchnh khi mt s kin c pht hin - v d, pht hin ngng qua cho mt cm bin nhit n gin. Tin x l ca nt cm bin phi m bo tnh n gin v hiu qu nng lngc ci thin.

2.1.2B iu khin

B vi iu khin/ vi x l, FPGA v ASIC

B iu khin l ct li ca mt nt cm bin khng dy. N thu thp d liu t cccm bin, x l d liu ny, quyt nh thi gian v a im gi d liu n, nhn d liu t

B nh

Cm bin/CCCHThit b lin lc

Ngun cp

B iu khin


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cc nt cm bin khcv quyt nh hnh vi ca cc c cu chp hnh. Ngoi ra, n cn thchin cc chng trnh khc, sp xp cc giao thc giao tip v x l tn hiu theo thi gian tihn v cc chng trnh ng dng. N l khix l trung tm(CPU) ca nt.

S a dng trong nhim v x l to nn cc kin trc khc nhau ca b iu khin datrn s tho hip gia linh hot, c tnh, hiu qu nng lng v gi thnh.

Mt gii php l s dng b vi x l cho mc ch chung, nh my tnh bn. y lnhng b vi x l rt mnh nhng tiu th nng lng qu ln. Cc b x l n gin hn cth to ra bng cch s dng cc h thng nhng. Cc b x l ny thng c gi l cc bvi iu khin. c im chnh khin cc vi iu khin c bit ph hp vi cc h thngnhng l s linh hot trong vic kt ni vi cc thit b khc (nh b cm bin), tp lnh cthit lp x l tn hiu theo thi gian ti hn, v nng lng tiu th thp. Mt im thuntin na l n t

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