机械毕业设计英文外文翻译51采煤工作面无线传感器网络物理层设计UWB技术.docx

机械毕业设计英文外文翻译51采煤工作面无线传感器网络物理层设计UWB技术.docx

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机械毕业设计英文外文翻译51采煤工作面无线传感器网络物理层设计UWB技术

翻译部分

英文原文

CoalFaceWirelessSensorNetworkPhysicalLayerDesignBasedOnUWBTechnology

Abstract

Inordertoguaranteethesafetyofcoalfaceproduction,itisnecessarytomonitorandsurveillancefaceShearer,scrapertransportplanes,hydraulicsupport,transportmachines,brokenmachinesetc.Atpresent,itisdifficultforthecabletransmissionmodetoadapttochangesintheworksiteofthecoalface.Transmissionlinesareoftendamagedandsnappedforvariousfactors,weusewirelesssensornetwork（WSN）,whichisflexibletobeplacedandextensible,toresolvethisproblem.ThispaperdiscussthedesignoftheWSNtransceiverforcoalfacewithUWBtechnology.Thiskindoftransceiverhassomeusefuladvantagesuchaslowcost,lowpowerconsumption,simplestructure,easytoimplementthedesignofthehardware,noneedtoestimatethecoalfaceChannelcharacteristics.However,detectionefficiencyisslightlylower,buttheerrorratecanmeettherequirement.

1.Introduction

Coalfacemustfacethecomplicatedgeologicalconditionsandpoorworkingconditions.Inordertoensurethesafetyofproductioninthecoalface,itisnecessarytomonitorreal-timethefaceShearer,scrapertransportmachine,hydraulicsupport,reprintmachine,brokenmachinesandotherlargeequipments.Inaddition,wemustmonitorthegroundpressure,gas,carbonmonoxide,dustandotherenvironmentalparameters.Atthesametime,mobilevoiceandimagecommunicationsisrequired.Atpresent,thesignalmonitoredandderivedfromthecoalfaceistransmittedbycable.Asthefaceismovingconstantlyandthegoingofthecoalminingprocess,allkindsoflarge-scaleironandsteelequipmentsinthecoalfaceneedtobeboostedcircularlyandcontinually.Theshapeofthespaceisconstantlychangingwiththechangeoftherelativepositionoftheequipments.Correspondingly,communicationincableisdifficulttobeapplicablewiththeworkingscenechanging,sotransmissionlinesisdamagedorsnappedfrequently,andthecoalfacemobilevoiceandimagecommunicationisimpossible.AlltheseissuescausemanylatenttroubletotheSafetyoftheproduction.Wethinkwirelesssensornetwork（WSN）isfeasibletoimplementmonitoringandsurveillancetothecoalface,forithassomeusefulcharactersofplacingflexibly,expandingsimply,movingeasilyandself-organization.

2.WSNarchitectureinthecoalface

ThesensornetworksystemstructureoftheminingCoalfaceisshowninFigure1.InthisFigure,thesensornodessendtheinformationofacquistionthroughoneormorejumpstotheclusternode,thebasestation（sinknode）isresponsibleforthecollectionofdata,andtransmitthemtotaskmanagementnodethroughup-slotnetwork,taskmanagementNodeisresponsiblefortheintegratedprocessthedataandalsoissuedinstructiontosensornetworks.Thetunnelofcoalfaceisalimitedspace.Bracket,shearer,transportandotherlargemetalequipmentsarelayoutandcoal,rocksandothermediaisanon-uniformrestrictedspace,whichallmakethetransmissionchannelmorecomplex,fadingandmulti-pathphenomenamoreseriousinthetransmissionofwirelesssensornodessignal.Thesearedifferentfromsensornetworksontheground.Therefore,

thedesignoftransceivernodeofitisparticularlyimportant.Atpresent,therearethreemaintechnologiesofthephysicallayerinwirelesssensornetworks:

narrow-bandmodulationtechnology,spreadspectrumtechnologyandultra-wideband（UWB）technology.WhileUWBtechnologypossessessomeattractiveadvantagessuchaslowpowerspectrumdensity,low-complexitysystem,Lowsensitivitytothechannelfading,bettersecurityandsoon.Consideringtheadvantagesandthecharacteristicsofcoalfacenaturally,wehaveadoptedImpulseradioultra-wideband（IR-UWB）technology,andthereasonsarefollowed:

1）UWBtechnologyconsumeslowerpowerandhaslowerpowerspectrum.Lowpowerconsumption,low-costandsmallsizearethemostimportantfeatureofwirelesssensornetworknodes.Narrow-bandmodulationtechnology,spreadspectrummodulationtechnologygenerallyusesinecarrier,IFandRFcircuitsexistinthesystems,soconsumingmorepowerthantheUWBtechnologywithnocarrier.Transmissionmediuminthecoalfaceisnon-uniform,whichleadingtomoretransmissionlossthanwirelesscommunicationssystemsontheground.Thereforelowpowerconsumptionbecomesparticularlyimportant.Inthecoalface,asWSNnodepresentszonaldistribution,nodesjustneedtocommunicatewithneighbor-nodes.TheWSNsystembasedonUWB,consuminglowertransmissionpower,canmeettherequirementsandavoidtheinterferencewitheachotherinthenarrow-bandcommunicationsnode.Inaddition,thelowpowerconsumptionandhighpenetratingpowerhelptodesignsafeequipmentandtransmitdisasterreliefsignal.2）Stronganti-interferenceability.Inthecoalface,electricalandmechanicalequipmenthasnarrowdistribution.Whenequipmentstartsorstop,electricalsparklemaycausealotofelectromagneticinterference.Sogoodanti-interferencecapabilityisstronglyrequiredinthewirelesscommunication.3）GoodAnti-interferencetomulti-pathability.Coalfacehassomeinherentcharacters,suchasnarrowspace,moretypesofmedia,amulti-pathintensivechannel,whileIR-UWBcanbeappliedtothiscomplicatedenvironmentwithitsadvantages:

narrowPulsewidth,smallpulsedurationratio,highmulti-pathresolution,stronganti-multi-pathandfadingCapacity.4）Simplestructure.ThecharactersofIR-UWB,suchasnomodulationandup/downconversingfrequency,simpletransmitterstructure,lowerpowerconsumption,makeitmoreacceptable.Accordingtothecomplexityofthenodeandpowerconsumptionintoconsiderations,IR-UWBtechnologyisveryapplicabletothedesignofthewirelesssensornetworkphysicallayer.Therefore,comparedtonarrow-bandmodulationtechnology,spreadspectrumtechnology,thewirelesscommunicationsystembasedontheUWBtechnologypresentagoodperformanceontheenergyconsumption,robustness,anti-multi-pathandanti-noise,andsoon.

ThemodulationofIR-UWBaremainlyPAM（OOK）,PPMandBPM（Bi-PhaseModulation）,butthepresenceoflinesspectruminPAMandPPMnotonlymakeultra-widebandpulsesignaldifficulttomeetacertainspectrumRequirements,butalsoreducethepowerutilization,therebyitincreasesenergyconsumption.SeveralIR-UWBsignalsinthefrequencyspectrumareshowninFigure2andFigure3.AsWSNsystemrequireslowpowerconsumption,PAMmodulationoftenuseOOKmethod,whichhassimplestructure.ButOOKhaspoorperformanceontheBER（BitErrorRate）,anti-noiseperformanceofBPMmodulationsuchasanti-Jitternoiseisbetter.ISIwouldbeintensifiedifweadoptedPPMundertheconditionsofintensivemulti-pathenvironmentinthecoalface.Therefore,weuseBPMformsinthetransceiversystemofthecoalface.

A.Thedesignoftransmittingsystem

ThetransmitterwhichadoptsBPMformsisshowninFigure4.Thesignaldistortion,interferenceandnoisebroughtbythespecialenvironmentincoalfaceneedencodedprotectionthroughchannelcodinginterweavemodule.Datarateoftheoriginalinformationislower,whichmakeitdifficulttomeettherequirementsofFCCintheabsenceofmodulation.Weneedtousespreadspectrumcodetransformtheoriginalinformationwhichhasalargerdurationratiointoasmallerdurationratio（nanosecond）.ThenwecangenerateBPMpulsesignalthroughthepulseformationcircuit,whichcanmeettherequirementofFCC.FinallyusefilterstooptimizeBPMsignalfurthertoenlargethespectrumandsenditoutfromtheantenna.

ThesystemusesGaussianpulsetobetheformofUWBsignal.IfawavetransmittedisthefirstorderderivativeRayleighpulse,thesignalaftersendingoutthroughtheantennaistransformedtobethesecondorderderivativeoftheGaussianpulseinidealcircumstances.Inaddition,thelowertheorderoftheGaussianpulseis,thefartherthesignalcanbesentunderthesamedatarate.HereweselecttheGaussiandoublet,whosehardwarecircuitisrelativelyeasytoimplementandconsumelowerenergy.Althoughinterferenceofnarrow-bandcommunicationsystemisexistinthegroundwirelesscommunications,thehigherorderoftheGaussianis,thebetterGaussiannarrowpulseshape.Butwedonotneedtoconsiderinterferencetotheothernarrow-bandcommunicationsinthecoalface,forsofar,wirelesscommunicationssystemsisbasicallynon-existentinthemine'scoalface.AsecondGaussianpulseshapecanbeexpressedas:

Here,

isusedtoexpressthepulsewidth,Supposethattheinputsignalis

eachbitisexpressedby

anditscycleis

.Afterthechannelencoder,everybitofthesequence

karerepeatedbyNtimes.Thecodedurationtimeis

soeachbitiscomposedbyNpulsewidth.Ifwesupposethepseudo-randomsequenceofsensorsnodekis

thelengthofthesequenceisN,thedurationofthecodesliceisThesequenceof

canbereplacedby

andthe

.Thetimecoordinateofi-thbitintheframedatestreamsentbysensornodekis

.

when

when

.Wecanthink

inpracticalapplication.

WhenN=1,theUWBwavesandwaveformsentareshownintheFigure5.WaveformintheFigurefromthetoptotheendistheUWBwaveform（thewaveformofcode“0”andthewaveform“1”）;thewaveformgeneratedwhenseveralcodearesendout;UWBwaveformwhengetthroughband-passfilter.

B.Thedesignofreceiversystem

Therecerverstructureisshowninfigure6.Thesignalreceivedthroughthereceivingantennawillgothroughthelownoiseamplifierandfilter.Thentheamplitudeofthesignalwillbedetectedusingtunn