Software Defined Radio Architectures Systems and Functions.docx

Software Defined Radio Architectures Systems and Functions.docx

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SoftwareDefinedRadioArchitecturesSystemsandFunctions

Softwaredefinedradio（SDR）isahottopicinthetelecommunicationsfield,withregardtowirelesstechnology.Itisoneofthemostimportanttopicsofresearchintheareaofmobileandpersonalcommunications.SDRisviewedastheenablerofglobalroamingandaplatformfortheintroductionofnewtechnologiesandservicesintoexistinglivenetworks.Itthereforegivesnetworksagreaterflexibilityintomobilecommunications.Itbridgestheinter-disciplinarygapinthefieldasSDRcoverstwoareasofdevelopment,namelysoftwaredevelopmentanddigitalsignalprocessingandtheinternet.Itextendswellbeyondthesimplere-configurationofairinterfaceparameterstocoverthewholesystemfromthenetworktoservicecreationandapplicationdevelopment.Reconfigurabilityentailsthepervasiveuseofsoftwarereconfiguration,empoweringupgradesorpatchingofanyelementofthenetworkandoftheservicesandapplicationsrunningonit.Itcutsacrossthetypesofbearerradiosystems（Pagingtocellular,wirelesslocalareanetworktomicrowave,terrestrialtosatellite,personalcommunicationstobroadcasting）enabletheintegrationofmanyoftoday'sdisparatesystemsinthesamehardwareplatform.Alsoitcutsacrossgeneration（secondtothirdtofourth）.Thisvolumecomplementsthealreadypublishedvolumes1and2oftheWileySeriesinSoftwareRadio.Thebookdiscussestherequirementsforreconfigurabilityandthenintroducesnetworkarchitecturesandfunctionsforreconfigurableterminals.Finallyitdealswithreconfigurationinthenetwork.ThebookalsoprovidesacomprehensiveviewonreconfigurabilityinthreeveryactiveresearchprojectsasCAST,MOBIVASandTRUST/SCOUT.Keyfeaturesinclude:

PresentsnewresearchinwirelesscommunicationsSummarisestheresultsofanextensiveresearchprogramonsoftwaredefinedradiosinEuropeProvidesacomprehensiveviewonreconfigurabilityinthreeveryactiveresearchprojectsasCAST（ConfigurableradiowithAdvancedSodftwareTechnology）,MOBIVAS（DownloadableMOBIleValueAddedServicesthroughSoftwareRadioandSwitchingIntegratedPlatforms）,TRUST（TransparentlyRe-configurableUbiquitousTerminal）andSCOUT（SmartUser-CentricCommunciationEnvironment）.

SoftwareDefinedRadio:

Origins,DriversandInternationalPerspectives

Overthepastfewyearssoftwareradiohastransitionedfromanesotericacademicideatoarapidlycommercialisingtechnologythatinthecomingdecadewillrevolutionisethemobiletelecommunicationsmarketplace.Writtenforindustryprofessionalsinengineeringandcommercialroles,aswellasthoseinacademiaandresearch,thisbookwillprovideacomprehensivecontextforallthosealreadyactiveinorenteringthefield.

WalterTuttlebee,himselfapioneerofsoftwareradioinEurope,hasgatheredcontributionsfrommanyoftheacknowledgedworldexpertsinsoftwareradio-leadersoperatingattheheartofthesoftwareradioworldtoday-whosharetheirexperienceandinsightintothebackground,thepresentandthefutureevolutionofthetechnologyandtheindustry.ContributionsfromNorthAmerica,EuropeandAsiaensureacomprehensiveoverviewoftheglobalSDRscene.Thestructuredapproachensuresthatthebookcomprehensivelyaddressesthekeyissuesinthetitle-theoriginsofsoftwareradio,whathasbeen（andis）drivingitscommercialisationandwhatishappeningontheinternationalscene

Thebookincludes:

∙acomprehensivereviewoftheoriginsofsoftwareradiointhedefenceindustry

∙aninsider'sviewoftheorigins,evolution,roleandactivitiesoftheSDRForum

∙asummaryoftheMITSloanstudyintothedriversofglobalsuccessinthemobilewirelessmarketplace

∙areviewofenduserandmobilenetworkoperatorperspectivesofsoftwareradioandwhatthevalueitcanoffer

∙insiders'summariesofrecentSDRresearchactivitiesinEuropeandJapan

∙coverageoftheregulatoryissuesassociatedwithSDRandthecurrentapproachesbeingtakeninNorthAmericaandEurope,withcontributionsfromtheregulatorsthemselves

∙adescriptionofthefirststepstoSDRstandards-theETSIMExEstandard

∙descriptionsofsomeofthefirstcommercialsoftwaredefinedradioproducts,forbothdefenceandcommercialapplications

EndorsedwithaforewordfromJosephMitolaIII,'thefatherofsoftwareradio'

SoftwareDefinedRadio:

TheSoftwareCommunicationsArchitecture

TheSoftwareCommunicationsArchitecture（SCA）establishesanimplementation-independentframeworkforthedevelopmentofJointTacticalRadioSystemsoftwareconfigurableradios.ItspecifiestheOperatingEnvironment,servicesandinterfacesthatapplicationsuse.

SoftwareDefinedRadio:

TheSoftwareCommunicationsArchitecturefocusesontheissuesandbenefitsassociatedwithdevelopingaradiosystemincompliancewiththeSCAspecification.Thisbookprovidesacomprehensive,practicalintroductiontobuildingaSCA-compliantsystemtakingthereaderthroughthehistoricalandconceptualbackgroundtohelpfillinginthegapsbetweentheintentoftheSCAspecificationandthepractice.

Keyfeatures:

∙PresentsapracticalapproachtotheSoftwareCommunicationsArchitecture

∙Providesanexample-orientedunderstandingoftheusageoftheSCAandthusallowsthereadertoextendtheconceptsandpracticetomorecomplicatedmulti-processordistributedenvironments.

∙CoverstheOperatingEnvironment:

aCoreframework,CORBAmiddleware,POSIXoperatingsystemsandDomainprofiles.

∙Featuresanaccompanyingwebsitewithappendices,andlinkstofurtherinformationontheSCA.

Thisinvaluablereferencewillprovideapplicationsprogrammers,designers,professionalresearchers,wirelessmanufacturersandoperatorswithanindispensableguidetotheSoftwareCommunicationsArchitecture.Advancedundergraduateandpostgraduatestudentsonmobileandwirelesscommunicationscourseswillalsofindthistobeanexcellentguidetothetopic.

Software-definedradio

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Asoftware-definedradiosystem,orSDR,isaradiocommunicationsystemwherecomponentsthathavebeentypicallyimplementedinhardware（e.g.mixers,filters,amplifiers,modulators/demodulators,detectors,etc.）areinsteadimplementedbymeansofsoftwareonapersonalcomputerorembeddedsystem.[1]WhiletheconceptofSDRisnotnew,therapidlyevolvingcapabilitiesofdigitalelectronicsrenderpracticalmanyprocesseswhichusedtobeonlytheoreticallypossible.

AbasicSDRsystemmayconsistofapersonalcomputerequippedwithasoundcard,orotheranalog-to-digitalconverter,precededbysomeformofRFfrontend.Significantamountsofsignalprocessingarehandedovertothegeneral-purposeprocessor,ratherthanbeingdoneinspecial-purposehardware.Suchadesignproducesaradiowhichcanreceiveandtransmitwidelydifferentradioprotocols（sometimesreferredtoaswaveforms）basedsolelyonthesoftwareused.

Softwareradioshavesignificantutilityforthemilitaryandcellphoneservices,bothofwhichmustserveawidevarietyofchangingradioprotocolsinrealtime.

Inthelongterm,software-definedradiosareexpectedbyproponentsliketheSDRForum（nowTheWirelessInnovationForum）tobecomethedominanttechnologyinradiocommunications.SDRs,alongwithsoftwaredefinedantennasaretheenablersofthecognitiveradio.

Asoftware-definedradiocanbeflexibleenoughtoavoidthe"limitedspectrum"assumptionsofdesignersofpreviouskindsofradios,inoneormorewaysincluding:

[2]

∙spreadspectrumandultrawidebandtechniquesallowseveraltransmitterstotransmitinthesameplaceonthesamefrequencywithverylittleinterference,typicallycombinedwithoneormoreerrordetectionandcorrectiontechniquestofixalltheerrorscausedbythatinterference.

∙softwaredefinedantennasadaptively"lockonto"adirectionalsignal,sothatreceiverscanbetterrejectinterferencefromotherdirections,allowingittodetectfaintertransmissions.

∙cognitiveradiotechniques:

eachradiomeasuresthespectruminuseandcommunicatesthatinformationtoothercooperatingradios,sothattransmitterscanavoidmutualinterferencebyselectingunusedfrequencies.

∙dynamictransmitterpoweradjustment,basedoninformationcommunicatedfromthereceivers,loweringtransmitpowertotheminimumnecessary,reducingthenear-farproblemandreducinginterferencetoothers.

∙wirelessmeshnetworkwhereeveryaddedradioincreasestotalcapacityandreducesthepowerrequiredatanyonenode.[3]Eachnodeonlytransmitsloudlyenoughforthemessagetohoptothenearestnodeinthatdirection,reducingnear-farproblemandreducinginterferencetoothers.

Operatingprinciples[edit]

Idealconcept[edit]

Theidealreceiverschemewouldbetoattachananalog-to-digitalconvertertoanantenna.Adigitalsignalprocessorwouldreadtheconverter,andthenitssoftwarewouldtransformthestreamofdatafromtheconvertertoanyotherformtheapplicationrequires.

Anidealtransmitterwouldbesimilar.Adigitalsignalprocessorwouldgenerateastreamofnumbers.Thesewouldbesenttoadigital-to-analogconverterconnectedtoaradioantenna.

Theidealschemeisnotcompletelyrealizableduetotheactuallimitsofthetechnology.Themainprobleminbothdirectionsisthedifficultyofconversionbetweenthedigitalandtheanalogdomainsatahighenoughrateandahighenoughaccuracyatthesametime,andwithoutrelyinguponphysicalprocesseslikeinterferenceandelectromagneticresonanceforassistance.

Receiverarchitecture[edit]

Mostreceiversuseavariable-frequencyoscillator,mixer,andfiltertotunethedesiredsig