翻譯部分英文原文CoalFaceWirelessSensorNetworkPhysicalLayerDesignBasedOnUWBTechnologyAbstractInordertoguaranteethesafetyofcoalfaceproduction,itisnecessarytomonitorandsurveillancefaceShearer,scrapertransportplanes,hydraulicsupport,transportmachines,brokenmachinesetc.Atpresent,itisdifficultforthecabletransmissionmodetoadapttochangesintheworksiteofthecoalface.Transmissionlinesareoftendamagedandsnappedforvariousfactors,weusewirelesssensornetwork(WSN),whichisflexibletobeplacedandextensible,toresolvethisproblem.ThispaperdiscussthedesignoftheWSNtransceiverforcoalfacewithUWBtechnology.Thiskindoftransceiverhassomeusefuladvantagesuchaslowcost,lowpowerconsumption,simplestructure,easytoimplementthedesignofthehardware,noneedtoestimatethecoalfaceChannelcharacteristics.However,detectionefficiencyisslightlylower,buttheerrorratecanmeettherequirement.1.IntroductionCoalfacemustfacethecomplicatedgeologicalconditionsandpoorworkingconditions.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.WSNarchitectureinthecoalfaceThesensornetworksystemstructureoftheminingCoalfaceisshowninFigure1.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.ThedesignoftransmittingsystemThetransmitterwhichadoptsBPMformsisshowninFigure4.Thesignaldistortion,interferenceandnoisebroughtbythespecialenvironmentincoalfaceneedencodedprotectionthroughchannelcodinginterweavemodule.Datarateoftheoriginalinformationislower,whichmakeitdifficulttomeettherequirementsofFCCintheabsenceofmodulation.Weneedtousespreadspectrumcodetransformtheoriginalinformationwhichhasalargerdurationratiointoasmallerdurationratio(nanosecond).ThenwecangenerateBPMpulsesignalthroughthepulseformationcircuit,whichcanmeettherequirementofFCC.FinallyusefilterstooptimizeBPMsignalfurthe