mạng cảm biến không dây

  • Published on
    26-Nov-2015

  • View
    125

  • Download
    1

Embed Size (px)

DESCRIPTION

ew

Transcript

<p>Mng Cm Bin Khng Dy</p> <p>1.TNG QUAN MNG CM BIN KHNG DY.31.1 Gii thiu:31.1.1 C 4 thnh phn c bn to nn 1 mng cm bin:31.1.2 Hiu qu s dng cng sut ca WSN da trn 3 yu t:31.1.3 Mt vi c im ca mng cm bin:31.2 Tng quan k thut41.2.2 K thut truyn v tuyn:41.2.3 Phn mm ng dng:42. K THUT MNG CM BIN KHNG DY.42.1 Node.42.2 Phn cng v phn mm:52.2.1 Phn cng:52.3 Phn loi theo m hnh phn b:62.3.1 Category 1 WSN (C1WSN).62.3.2 Category 2 WSN (C2WSN)62.4 Mi trng hot ng ca WSNs.72.5 Cng ngh hin nay:73. GIAO THC IU KHIN TRUY CP TRONG WSNs.83.1 M hnh giao thc cho WSNs.83.2 Cc giao thc MAC cho mng WSNs.94. NH TUYN.94.1 Vn nh tuyn.94.1.1 S phn phi v tp hp d liu.94.1.2 Thit k v thch thc trong nh tuyn.104.1.2.1 Kch thc mng v c tnh thay i theo thi gian.104.1.2.2 Ti nguyn hn ch.104.2 Cc giao thc nh tuyn.104.2.1 Cc gii thut nh tuyn cho mng.104.2.2 nh tuyn theo v tr.114.2.2.1 Nguyn l:114.2.2.2 u im v nhc im.125. GIAO VN:135.1 Yu cu thit k trong giao vn.135.2 Cc giao thc iu khin giao vn.135.2.1 Cc giao thc iu khin giao vn ang dng.135.2.3 Khi phc gi b mt.146. QUN L MNG WSNs.156.1 Yu cu qun l mng v cc kiu qun l truyn thng.156.1.1 Yu cu qun l mng.156.1.2 Cc kiu qun l truyn thng.156.2 Vn thit k qun l mng.167. NG DNG.177.1 ng dng trong qun s v an ninh quc gia:177.2 ng dng trong bo v mi trng.177.3 ng dng trong thng mi187.4 ng dng trong y hc.18</p> <p>10</p> <p>1.TNG QUANG MNG CM BIN KHNG DY.</p> <p>1.1 Gii thiu:Mng cm bin khng dy (Wireless Sensor Network) l s kt hp cc kh nng cm bin, x l thng tin v cc thnh phn lien lc to kh nng quan st, phn tch v phn ng li vi cc s kin,hin tng xy ra trong mi trng c th no .</p> <p>Hnh 1 : M hnh mng cm bin khng dy.1.1.1 C 4 thnh phn c bn to nn 1 mng cm bin:- Cc cm bin c phn b theo m hnh tp trung hay phn b ri.- Mng li lin kt gia cc cm bin (c dy hoc v tuyn).- im trung tm tp hp d liu .- B phn x l d liu trung tm.1.1.2 Hiu qu s dng cng sut ca WSN da trn 3 yu t:- Chu k hot ng ngn.- X l tn hiu ni b ti cc node gim thi gian truyn.- M hnh dng multihop lm gim chiu di ng truyn .1.1.3 Mt vi c im ca mng cm bin:- Cc node phn b dy c.- Cc node d hng.- Giao thc mng thay i thng xuyn.- Node b gii hn v kh nng tnh ton,cng sut, b nh.- Khng c thng nht ton h thng v s lng node nhiu.1.2 Tng quan k thut1.2.1 Cm bin:- Chc nng c bn.- X l tn hiu.- Nn v pht hin,sa li.- Phn chia Cluster.- T phn nhm.1.2.2 K thut truyn v tuyn:- Dy truyn sng.- S h hi ng truyn.- K thut iu ch.- Giao thc mng.1.2.3 Phn mm ng dng:- H iu hnh.- Phn mm mng.- Phn mm kt ni c s d liu trc tip.- Phn mm middleware.- Phn mm qun l d liu.</p> <p>2. K THUT MNG CM BIN KHNG DY.2.1 Node.</p> <p>Hnh 2: Cc thnh phn trong mt Node.Cc thnh phn cu to nn mt Node :- Mt cm bin (1 hay mt dy cm bin).- n v x l.- n v lin lc bng v tuyn.- Ngun cung cp.- Cc phn ng dng khc.Cc node c kh nng lin lc v tuyn vi cc node ln cn v cc chc nng c bn nh x l tn hiu, qun l giao thc mng v bt tay vi cc node ln cn truyn d liu ti trung tm.</p> <p>Hnh 3: S pht trin cng ngh ch to cm bin.2.2 Phn cng v phn mm:2.2.1 Phn cng:- Ngun cung cp.- Lu tr v tnh ton.- Cm bin.- Lin lc.2.2.2 Phn mm:- H iu hnh.- WSN Sensor Driver.- B x l thng tin.- B x l d liu.</p> <p>Hnh 4: Phn cng v phn mn node</p> <p>2.3 Phn loi theo m hnh phn b:2.3.1 Category 1 WSN (C1WSN).- H thng li kt ni a ng gia cc node qua knh truyn v tuyn s dng giao thc nhtuyn ng,cc node tm ng i tt nht n ch .- Vai tr ca cc node nh cc trm lp vi khong cch rt ln.- X l d liu cc node chuyn tip. Mng phc tp.2.3.2 Category 2 WSN (C2WSN)- M hnh im-im hay a im-im, ch yu l cc lin kt n gia cc node (single hop),dng giao thc nh tuyn tnh.- Mt node khng cung cp thng tin cho cc node khc.- Node chuyn tip khng c kh nng x l d liu cho node khc.- Khong cch vi trm mt. Mng n gin.</p> <p>Hnh 5: M hnh mng.2.4 Mi trng hot ng ca WSNs.Node cm bin b rng buc bi mt s yu t:- Ngun cung cp: Cc node b gii hn bi nng lng cung cp.- Lin lc: Gii hn v bng thng, nhiu knh truyn, nh hng n tin cy, cht lng dchv v bo mt ca h thng.- Tnh ton: Cc node c cng sut tnh ton v b nh gii hn, nh hng n vic la chngii thut x l d liu.2.5 Cng ngh hin nay:- Kch thc, gi thnh v cng sut tiu th ca node gim, s thng minh ca node phi tng ln.h thng cm bin kt hp cc k thut tin tin nh cng ngh nano, mng phn b, thng tin vtuyn bng rng- Vic tiu chun ha cng rt quan trng. To ra cc tiu chun chung s gip mng WSNs ngdng rng ri hn trong thc t, c kh nng giao tip vi cc mng khc, giao din Internet,cung cp cc dch v a dng hn. Cc nghin cu ang hng n cc k thut ch to cmbin mi, h thng mng cm bin phn b, tch hp cm bin trong cc h thng thng mi, htr hiu qu cho cc qu trnh ra quy t nh.</p> <p>3. GIAO THC IU KHIN TRUY CP TRONG WSNs.Mng khng dy da trn truyn sng in t qua mi trng khng kh, tun theo cc c tnhtruyn sng nn vic i x vi cc node trong mng phi nh nhau, t c iu ny vic s dnggiao thc iu khin truy nhp mi trng MAC (Medium Access Control) l cn thit.3.1 M hnh giao thc cho WSNs.Xut pht t m hnh OSI, giao thc MAC c xy dng lp thp ca lp lin kt d liu (DataLink Layer_DDL). Lp cao ca DDL c xem nh lp iu khin logic (LLC).Lp MAC nm ngay trn lp vt l v n cung cp cc chc nng sau:- Kt hp d liu vo frame gi .- Tch frame thu c ly thng tin kim tra li khi phc lai thng ip.</p> <p>Hnh 6: M hnh tham kho OSI v cu trc lin kt lp d liu.Lp LLC ca DDL cung cp giao din trc tip cho lp cao hn nhm mc ch ngn cch lp caovi cc lp thp hn pha di3.2 Cc giao thc MAC cho mng WSNs.- Schedule-Based Protocols: giao thc to ra s sp t trc iu tit truy cp ti nguyn trnhxung t gia cc node, thng thng cc ti nguyn l thi gian, bng tn- Random Access-Based Protocols: giao thc truy cp ngu nhin da trn s tranh chp, khng ihi s phi hp gia cc node ang truy cp knh truyn. Cc node ng ngng mt khongthi gian trc khi th truy cp tr li knh truyn.4. NH TUYN.4.1 Vn nh tuyn.4.1.1 S phn phi v tp hp d liu. thc hin vic trao i thng tin t cc node n base station th phi c mt ng kt ni trc tip tuy nhin vi kt ni ny th s suy gim nng lng mt cch nhanh chng. Do lm hn ch kh nng bao ph rng ca mng. Do gii quyt nhc im ny th d liu trao i gia cc node cm bin v cc trm c truyn a chng(Multihop). Cc lin kt ny c th ko di khong cch v to ra mt ng linh hot. Phng php ny lm gi m ng k can nhiu gia cc node ang tranh chp truy cp knh truyn c bit l trong WSN mt cao.</p> <p>Hnh 7: M hnh nh tuyn.Trong Multihop cc node trung gian phi tham gia vo vic truyn ti cc gi d liu gia ngun v ch. Xc nh node trung chuyn l vn ln trong gii thut inh tuyn bo m s chnh xc tnh n nh v kh nng ti u.4.1.2 Thit k v thch thc trong nh tuyn.4.1.2.1 Kch thc mng v c tnh thay i theo thi gian.Cc node cm bin hot ng vi kh nng tnh ton, lu tru v thng tin hn ch do gii hn ngun nng lng cung cp, mt cm bin cng c th rt it hoc dy c. Trong mang WSNs cc node trng thi ng v kh nng thch ng cao do yu cu t phn b v tit kim nng lng. Cc node phi t iu chnh hot ng p ng vi s tht thng khng th on trc ca cc kt ni khng dy.4.1.2.2 Ti nguyn hn ch.Vn ngun nng lng cung cp cho s lng node ca mng hot ng.Kh nng thit k mt gii thut nh tuyn thng minh cho mng hot ng vi hiu qu cao nht ang l vn ln.4.2 Cc giao thc nh tuyn.4.2.1 Cc gii thut nh tuyn cho mng.- Proactive(khi to trc): da trn s phn pht theo chu k thng tin t c bn nh tuyn nht qun v chnh xc n tt c cc node ca mng. Cu trc mng c th bng phng hay phn cp. Trong phng php ny cu trc phng th tm ng i ti u hn.- Reactive(phn ng): xy dng tuyn n mt ch no theo nhu cu. Gii thut ny thng khng chuyn ti thng tin qua tt c cc node ca mng. Do chng da trn nh tuyn ng tm ra ng i.- Hybrid(hn hp): da trn cu trc mng to nn tnh n nh v kh nng m rng cho cc mng c kch thc ln. Gii thut ny chia mng ra thnh cc cluster, do s lng ln v tnh di ng khi cc node vo hay ra khi cc cluster. Gii thut ny kt hp Proactive trong cc cluster v Reactive cho s lin kt cc cluster.Cc k thut nh tuyn:- Dng 1: giao thc dnh cho mng c kin trc phng ti thiu cho overhead xy dng cho htng mng v c kh nng tm ra nhiu ng lin lc gia cc node vi sai s cho php.- Dang 2: dng trong mng c cu trc tit kim nng lng, n nh v kh nng m rng. Cc node mng c sp xp vo cc cluster trong mt node mng ln nht c vai tr nh mt cluster head. Cluster head c vai tr phi hp hot ng ca cc node trong cluster v chuyn thng tin gia cc cluster. Vic phn hoch gim nng lng tiu th v ko di thi gian sng ca mng.- Dng 3: dng phng php data-centric phn b yu cu trong mng. Phn nhim v cho cc node v nh r mt thuc tnh ring bit cho cc node. Kiu thng tin c th dng nhBroastcasting, anycasting, Geo-casting..- Dng 4: dng v tr ch ra mt node cm bin. nh tuyn da trn v tr rt hu ch cho cc ng dng m v tr ca node trong vng a l c th c hi bi node ngun. Yu cu nh th c th nh r vng no m cc hin tng quan tm c th xy ra hay ln cn vi im c bit no trong vng hot ng ca mng.4.2.2 nh tuyn theo v tr.4.2.2.1 Nguyn l:Dng thng tin v v tr tm ra tuyn lin lc hiu qu t ngun n ch. Khi cc node s gi vai tr chuyn tip gi(forwarding), do n phi hiu bit v cu hnh ton mng.- Forwarding: Most-forward-within-R(MFR): chn node nm xa nht trong s cc node nm trong vng ph R Nearest-forward-progress(NFP):chn node gn nht. node NFP c chn nhn d liu t node MH. y l node gn nht tnh t MH Compass routing chn node c gc nh nht to bi ng thng ni MH ti node c chn theo CMP c chn. Low energy forward chn node ti thiu nng lng c yu cu, node LEF c chn chuyn.</p> <p>Hnh 8: M hnh chn node truyn theo nng lng.- Gii thut khng ti u:ng i ti u t S1 n D l ng ni trc tip t S1 n D.</p> <p>Hnh 9: Gii thut nh tuyn khng hiu qu.</p> <p>- Gii thut ti u: Right-hand: mt gi xut pht t node Ni mun truyn n gi Nj, xung quanh c nhiu node ln cn th tuyn truyn c chn k tip l tuyn truyn u tin theo quy tc ngc chiu kim ng h tnh t ng thng ni NiNj. Tuy nhin gin ny gp phi trng hp khi tuyn ct ngang ng thng ni ngun v ch. face traversal: gii thut trnh cc ng ct ngang, nn tuyn c chn k tip theo quy tc Right-hand giao vi ng thng NiNj</p> <p>Hnh 10: Ci thin cht lng giao thc nh tuyn.4.2.2.2 u nhc.- u: nh tuyn theo v tr ph hp cho mng WSN v yu cu t thng tin cho iu khin v tng tc cc b gia cc node.- Nhc: cc lin kt bt i xng v cc ng giao nhau lm tng phc tp ca giao thc.5. GIAO VN:5.1 Yu cu thit k trong giao vn.Mng WSN c thit k vi cc tiu ch bo tn nng lng, iu khin tc nghn, tin cy trong phn phi d liu, an ninh v qun l. Hai tiu ch quan trng l iu khin tc nghn v khi phc d liu b mt.- Thc thi iu khin tc nghn v phn pht d liu tin cy. Dng k thut hop-to-hop iu khin tc nghn v khi phc gi b mt v n gim mt gi v tit kim nng lng- Cc giao thc giao vn phi lm n gin qu trnh xy dng kt ni, ci thin lu lng v tr thp.- Giao vn trong WSN phi trnh mt nhiu gi n mc c th v mt gi tng ng vi lng ph nng lng.- Giao thc giao vn phi m bo s cng bng gia cc node.- Dng nhiu dng kt hp cc giao thc ci thin cht lng.5.2 Cc giao thc iu khin giao vn.5.2.1 Cc giao thc iu khin giao vn ang dng.Nhiu giao thc lp giao vn c thit k cho mng WSN nh bng sau. iu khin tc nghn ln, xung. m bo tin cy hng ln, xung.CODA (congestion detection and avoidance), ESRT(Event to sink releable transport), RMST(releable multisegment transport), PSFQ(pump slowly, Fetch quickly), GARUDA.</p> <p>5.2.2Tc nghn.Hai phng thc iu khin tc nghn l end to end v hop to hop. Trong end to end node ngun pht hi tt nghn. Trong hop to hop node trung gian pht hin tt nghn v thng bo cho cc node gc. Phng php ny loi tt nghn nhanh hn, gim mt gi v tiu th t nng lng hn so vi end to end.- Hiu sut s dng nng lng tt nghn:</p> <p>Trong l t l nng lng trung bnh yu cu gi mt gi thnh cng.- End to end:</p> <p>- Hop by hop:</p> <p>T ta thy hiu qu s dng nng lng ca End to end ph thuc vo chiu dituyn(H) trong khi Hop by Hop khng ph thuc vo chiu di tuyn nn t s hiu sut cao hn.</p> <p>5.2.3 Khi phc gi b mt.- Cache: dung k thut Hop by hop v da trn lu tr ti cc node trung gian m n gi qua cho ti khi node gn n nhn c gi thnh cng hay khi timeout xy ra.- Noncache: dng k thut End to end ARQ tc l yu cu lp li t ng.Hnh di y so snh c tnh k thut khi phc gi b mt hop by hop v end to end trong lp giao vn. So snh s ln pht cn thit gi 10 gi qua mng trong 10 bc.</p> <p>Hnh 11: So snh s ln truyn yu cu gi 10 gi trong 10 bc ca Hop by Hop v End toEnd.</p> <p>- Khi t l thnh cng di 0.95 th s ln truyn li ca End to end tng gp i dn n hiu qunng lng tng gp i.</p> <p>6. QUN L MNG WSNs.6.1 Yu cu qun l mng v cc kiu qun l truyn thng.6.1.1 Yu cu qun l mng.Qun l mng gm mt chui chc nng gim st trng thi mng, pht hin cc h hng v s khc thng, qun l, iu khin v cu hnh cc thnh phn mng, duy tr hot ng thng thng v ci thin hiu qu lm vic v cht lng cc ng dng. thc thi cc nhim v ny, cng c qun l mng cn chn la thng tin thi gian thc ti cc thit b mng, phn tch thng tin, v iu khin ng dng da trn thng tin. Thng tin c sp xp nh mt c s thng tin qun l trn mi thit b mng. Thng thng, c mt trung gian trn mi thit b thu thp thng tin v tng trnh cho trung tm qun l mng. Do , qun l mng c th c xem nh mt ng dng.6.1.2 Cc kiu qun l truyn thng.- Giao thc qun l mng n gin (SNMP) c s dng kh rng ri. N gm: mt h thng qun l mng, cc thit b c qun l v cc phn trung gian. Mt li ch ca SNMP l s n gin ca n v s trin khai rng ri. Tuy nhin, n tiu th ng k bng thng bi v n thng dng ch mt phn nh thng tin qun l ti mt thi im. Bt li khc ca SNMP l n ch qun l cc phn t mng, khng cung cp qun l mc mng.- Lc cc hot ng vin thng (TOM) da trn qu trnh qun l mng v dch v. tng ca TOM l gii thiu qu trnh gm hot ng v s t ng ha. C 3 lp dc cho qun l dch v: qunl mng v h thng, thit lp dch v v hot ng v qu trnh chm sc khch hng. Theo chiu ngang, qun l dch v c chia thnh thc hin dch v, s m bo dch v v a ra cc danh sch dch v.TOM ch cung cp khung cho qun l dch v.- C SNMP v TOM u khng c thit k cho mng cm bin khng dy. Tuy nhin, chng ta c th dng s n gin ca SNMP v khung c chia phn lp ca TOM thit k kin trc qun lmng c hiu qu cho mng cm bin khng dy.6.2 Vn thit k qun l mng.- Mng WSN l mt dng c bit ca mng khng dy. Nhiu vn c ch ra mt cch cn thn trc khi thit k cng c qun l mng cho WSN. Chc nng qun l i hi cho WSN c nhn ra trc tin. SNMP cung cp 5 chc nng qun l: qun l h hng, qun l cu hnh, qun l cng vic tnh ton, qun l cht lng v qun l an ninh. V TOM, cc chc nng c phn lp trong phn t mng, qun l mng v qun l dch v. Trong mi lp, cc chc nng qun l khc nhau c th hin. Do , WSN cn cu trc qun l c phn lp vi cc chc nng qun l khc nhau cho mi lp. WSNcng cn cc thut ton qun l kha hiu qu cho an ninh. WSN cn cn cc chc nng qun l mi qun l d liu vi dng v mc ch d liu thu thp trong mng WSN kh khc so vi cc mng truyn.- Vn kin trc qun l cho mng WSN phi c xem xt cn thn. Qun l mng gm 3 phn chnh: ngi qun l, trung gian v MIB. Ngi qun l c dng qun l v iu khin mng gc v cng vic nh mt giao din vi cc h thng khc. Trung gian c t trong cc thnh phn c qun l, MIB l mt cy c cu trc hng i tng thng tin cho ngi qun l v trung gian v s sp xp thng tin qun l. Thnh thong mt h thng qun l mng gm nhiu ngi qun l phn b, mi th qun l mt phn mng. Phng php truy cp thng tin qun l v thay th nh qun l hay trung gian thng xc nh kin trc qun l. Phng php da trn trung gian c th tit kim bng thng bi v n c th tng trnh ch thng tin qun l cui cng. Mc d WSN c im tp hp d liu tp trung (trm gc), chng ging vi mng phn b hn. Kin trc qun l ghp da trn trung gian c th thch hp hn cho WSN.- Trong WSN, thng tin qun l c th c dng ci thin cht lng h thng. Cc chc nng qun l mng nn xem xt tt c cc im c bit ca WSN nh: Gii php qun l phi tit kim nng lng, dng lng nh bng thng v tuyn. Gii php qun l c kh nng m rng. Gii php qun l phi n gin v thc t v WSN l h thng phn b c ti nguyn hnch. M...</p>