TK nh thng minh bng mng zigbee

TK nh thng minh ng dng cng ngh zigbeeI. Zigbee networking protocol layer

Mi lp giao tip vi lp lin k qua cc im h tr truy nhp (SAPs)2II. Chi tit lp vt l chun IEEE 802.15.4

2.1 Energy Detection( pht hin nng lng)Khi mt thit b c k hoch truyn ti mt thng ip, n u tin i vo ch nhn pht hin v c tnh mc nng lng tn hiu trong knh mong mun. Nhim v ny c gi l pht hin nng lng (ED )My thu khng c gng pht hin cc loi tn hiu,m ch pht hin tn hiu c tnh ph hp chun ra2.2 Carrier SenseL cch xc nh khi tn s knh c s dngTn hieu trong cm bin sng mang c gii iu ch xem tin hieu /c v truyn co p ng chun PHY ko

2.3 Thng s cht lng ng dn( link quality indicator)La thng s cht lng gi d liu nhn mnh tn hiu c th dng o cht lng tn hiuTn hiu c SNR cao thi c coi la tn hiu tto c LQI c thc hin mi gi nhn ,c bo co ti lp MAC v c cc lp NWK v APL phn tch khi cn,vd : lop NWK da vo LQI thc hin rout message.2.4 nh gi knh ri (CCA)8 k hiu,co 3 phng thc CCA:CCA mode1ch kt qu pht hin tn hiu c mang vo ti khon. Neu mc nng lng trn ngi ED th coi la bnCCA mode 2: ch s dng kt qu ca CS,knh coi l bn nu tn hiu chim gi ph hp tng vt l ca thit bCCA mode 3 :tng hp mode 1 v mode 22.5 The PHY Constants and Attributes

Dch v d liu tng vt l( PHY data service)

III. Lp MAC

Cu trc siu khungLR-WPAN cho php sdng theo nhu cu cu trc siu khung. nh dng ca siu khung c nh r bi PAN coordinator. Mi siu khung c gii hn bi tng mng v c chia thnh 16 khe nhnhau. Ct mc bo hiu d ng beacon c gi i trong khe u tin ca mi siu khung. Nu mt PAN coordinator khng mun sdng siu khung th n phi dng vic pht mc beacon. Mc ny c nhim ng bcc thit b nh km,nhn dng PAN v cha ni dung mtcu trc ca siu khung. Siu khung c 2 phn hot ng v ngh. Trong trng thi ngh th PAN coordinator khng giao tip vi cc thit btrong mng PAN, v lmvic mode cng sut thp. Phn hot ng gm2 giai on: giai on tranh chp truy cp (CAP) v giai on tranh chp tdo(CFP), giai on tranh chp trong mng chnh l khong thi gian tranh chp gia cc trm c chi dng mt knh truyn hoc ti nguyn trn mng). Bt kthit bno mun lin lc trong thi gian CAP u phi cnh tranh vi cc thit bkhc bng cch sdng kthut CSMA-CA. Ngc li CFD gm c cc GTSs, cc khe thi gian GTS ny thng xut hin cui ca siu khung tch cc m siu khung ny c bt u khe st ngay sau CAP. PAN cooridinator c th nh vc by trong scc GTSs, v mi mt GTS chimnhiu hn mt khe thi gian. Khong thi gian tn ti ca cc phn khc nhau ca siu khung c nh ngha bi gi trca macBeaconOrder v macSuperFrameOrder. macBeaconOrder mtkhong thi gian m b iu phi coordinator truyn khung bo hiu tm ng. Khong thi gian gia hai mc beaconBI(beacon interval) c quan hti macBeaconOrder (BO)theo biu thc sau: BI = aBaseSuperFrameDuration*symbol, vi 0 BO 14. Lu rng siu khung c bqua nu BO=15.Gi trca macSuperFrameOrdercho bit di ca phn tch cc ca siu khung. Khong thi gian siu khung_SD (superframe duration) c quan hmacSuperFrameOrder_ SO theo biu thc sau: SD = aBaseSuperFrameDuration*symbol. Nu SO=15 th siu khung vn c th phn ngh sau mc beacon ca khung. SO2Phn tch cc ca mi siu khung c chia thnh 3 phn CAP,CFP v beacon. Mc beacon c pht vo u khe s0 mkhng cn sdng CSMA.

103.2 thut ton CSMA/CA

3.3 S kt hp,b kt hp cc thit b

c 4 service primitives MLME-Associate.request.MLME-Associate.indication, MLME-Associate.response,MLME-Associate.confirm

123.3 S kt hp,b kt hp cc thit b

3.4 thng bo mt kt ni (orphan notification)

3.4 qut knhThe ED scanThe orphan scanThe active scanThe passive scanIV. Lp mngDc phn 16 bit nh a chKhong cch truyn c nh ngha s chng( hops). Bn knh l max hops3.1 cu trc th bc (tree)

Lm.The network maximum depth ( nwkMaxDepth). Cm.The maximum number of children a parent can accept ( nwkMaxChildren). Rm.The maximum number of routing-capablechildren a parent can accept ( nwkMaxRouters). d.The depth of a device in a network. 173.2 Cch tnh a ch

183.3 routingLink cost:

Thm vo mng li, ZigBee cung cp vic broadcasting tin cy, mt k thut cho vic phn phi mt message n nhiu node trong mng. ZigBee cng cung cp multicasting c th gi mt message n bt k group cc node. V nh mt k thut tm ng back-up, ZigBee cung cp tm ng cy (tree routing) augment mng li ZigBee trong cc h thng gii hn RAM.

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3. 4 Joining and Leaving a Network