Zigbee无线传感器网络英文文献

Ｚigbee Wｉreｌess Sensor Ｎetworｋin Eｎvironmｅntal Monｉ

ｔoｒｉng Applicaｔions

I.ﻩZIGBEＥTECHNOLＯGＹ

Ｚigbeｅis a wiｒeless stanｄarｄbasｅd oｎIEEE8０2.15．４ｔｈaｔw ａs deveｌopeｄto ａｄdｒeｓs the unique nｅeds of most wiｒeｌess seｎｓｉｎg ａｎｄcｏntrol aｐplｉcationｓ. Tｅｃｈｎoｌｏｇy iｓlow cost, ｌow power，a ｌｏｗdａtａｒatｅ，highly rｅliable，ｈighly secure ｗireleｓs net ｗoｒkiｎg protｏcol tａrgeｔed towａrｄsａｕｔomａｔiｏn ａnd ｒｅmote con ｔｒol apｐlicatiｏns.It’s ｄepictｓｔwo keｙpｅrｆormance chaｒａｃterisｔicｓ–wirelｅｓs radio rａnｇe and ｄata trａnｓmissiｏｎｒatｅｏｆthｅｗｉrelesｓspeｃtrum.Cｏmpaｒｉnｇto otheｒwｉｒeless neｔwｏrking prｏｔｏco ｌｓｓuch as Bluｅtoｏth, Wi-Fi, UWB andｓoｏｎ, shoｗｓｅｘcｅｌlent ｔranｓmissioｎabilityｉｎlｏweｒｔransmissｉoｎraｔe and higｈｌy capacity of nｅｔwork.

A. ZｉgｂeｅFramework

Ｆrameworｋis ｍade up of a set oｆbｌocｋs called ｌayeｒs.Ｅach layｅｒpｅrforｍｓa specifｉc set oｆservices for the layer abovｅ.Ａs shｏｗｎin Fｉg.1. Ｔｈe IEＥE 8０2.15.４ｓｔandarｄdefinｅs thｅtwo loｗｅr ｌayers: ｔｈｅｐhysiｃaｌ（PHY)ｌaｙer aｎd thｅmediumａｃｃeｓs ｃoｎtｒｏｌ(MAC)lａｙer. Ｔhe Alｌiａncｅbｕiｌds ｏn this foundation by pｒoviding the ｎｅtｗork ａnd seｃurity ｌaｙｅr and the framework for the ａpｐliｃａtion layeｒ.

Fig.1 Fraｍewｏrk

The IEＥE 802．1５.4ｈａs two PHY lａyerｓthat ｏperate ｉn tｗo separate ｆrequenｃy ranges: 8６８／９15ＭHz and ２.4ＧHz. Mｏreoveｒ，ＭAC suｂ－layｅr c

ｏntｒoｌs aｃcesｓto thｅrａdiｏchａnｎel usinｇａＣSMＡ-CＡｍecｈaｎism. Ｉtｓrespｏｎsｉbilities mａy also ｉncluｄｅｔransmｉｔtｉｎｇbeacon ｆrameｓ, syncｈrｏｎｉzation, aｎｄpｒoｖiding a ｒelｉable trａnｓmiｓsｉoｎmechanism.

B. Ｚigbee’s Topoｌogy

The netｗork layer supports sｔａr, tｒｅe，and mesh toｐoｌogiｅｓ, as sh ｏwn in Fｉg.２. Iｎａstar tｏpology，the nｅｔwｏrk iｓcontrolled ｂyｏne ｓiｎgｌｅdｅｖｉce ｃａlled cooｒdｉnatoｒ. Thｅcoordinaｔor is ｒｅｓpons ｉbｌe for initiating ａnd ｍaintainｉng the ｄevicｅs ｏnｔhe netwoｒk．Ａll othe ｒdevicｅs，knowｎas ｅnｄdevｉｃes，dｉrectly comｍunicatｅｗith ｔhe coorｄinａtor. Ｉｎmesh aｎdｔrｅe tｏｐoｌｏgies，ｔhe coordinatｏr is ｒesponsible for ｓtａrtiｎｇｔhｅｎｅtwork ａnd foｒchoｏsing cｅrtain keｙｎe ｔｗorｋparａmｅteｒs, bｕt the nｅtwork may bｅｅｘｔendｅd throughｔhe use ofｒｏuｔers. Ｉｎtreeｎetworks, ｒｏuters ｍoｖe ｄatａａndｃｏnｔrol messageｓthrough the neｔwｏrk usｉｎg a ｈierarchicaｌrouｔingｓtraｔeｇy. Meｓh neｔｗｏrｋｓａｌlｏw fuｌl ｐeer-to-pｅeｒcoｍmunｉcation．

Fｉg.2 Ｍeｓｈtｏpologieｓ

Ｆig．３is ａｎｅtｗorｋmｏdeｌ，it ｓhｏwｓｔｈaｔsupports both ｓing ｌe-ｈoｐstａr ｔopologｙcoｎstrｕcteｄwith one coordinatｏr in thｅcenter anｄthe end dｅvices, and mesh toｐoｌogｙ. In ｔhe nｅtwoｒｋ，tｈe ｉntｅlligenｔｎodes aｒe comｐｏｓed ｂy Fuｌl Funｃtion Ｄｅviｃe (ＦFD）andＲeduced Funｃtｉon Devｉce （RFD)．Oｎly thｅFＦN defiｎｅs the fulｌfuｎctionality ａnｄcan bｅｃomeａｎetwｏｒｋｃoｏrdinａtｏr.Cｏorｄｉnatoｒmanages thｅnetwｏrk，ｉt is tｏsay that cｏｏrｄiｎator cａn starｔ a netwoｒkａnｄａllow