Crest Factor Reduction in Digital Front End Hardware for wireless Base Station Transmitter
| dc.contributor.author | Vaibhav | |
| dc.contributor.supervisor | Sharma, Sanjay | |
| dc.date.accessioned | 2008-08-27T08:49:10Z | |
| dc.date.available | 2008-08-27T08:49:10Z | |
| dc.date.issued | 2008 | |
| dc.description.abstract | ManyofthemodulationmethodscurrentlyinusesufferfromahighPeak-to-AveragepowerRatio(PAR),alsoknownastheCrestFactor(CF).TheGlobalSystemforMobilecommunication(GSM)isawidespreadsecond-generation(2G)systemthatusesconstantenvelopeGaussianminimumshiftkeyingmodulation.Theadvantageachievedbyconstantenvelopemodulationisthepossibilityofusingpower-efficientpoweramplifiers(PAs).However,itmightbebeneficialtocombinethecarriersinadigitalintermediatefrequencyinordertoreducethenumberofanaloguecomponents.Thedrawbackwiththisisthatthesignalisnomoreaconstantenvelopesignal,butithasastronglyfluctuatingenvelopewithahighCF.EnhancedDataratesforGSMEvolution(EDGE)isanenhancementtotheGSMsystemwiththeprimaryobjectiveoftriplingtheon-airdataratewhilemeetingessentiallythesamebandwidthoccupancyoftheoriginalGSMsignal.AlsointhecaseofEDGE,ifthecarriersarecombinedpriortoamplificationwewouldendupwiththesamehighCFproblem.WidebandCodeDivisionMultipleAccess(WCDMA)hasbeenselectedbytheEuropeanTelecommunicationsStandardsInstituteforwidebandwirelessaccesstosupportthird-generation(3G)services.OrthogonalFrequencyDivisionMultiplexing(OFDM)iscommonlyconsideredtobeatechnicalsolutionforfourth-generation(4G)services.Inbothcases,thetransmittedsignalisgeneratedbyaddingtogetheralargenumberofstatisticallyindependentsignals,whichleadstoasignalwithahighCF.ThehighCF,setsstrictrequirementsforthelinearityofthePA.Inordertolimittheadjacentchannelleakage,itisdesirableforthePAtooperateinitslinearregion.HighlinearityrequirementsforthePAleadstolowpowerefficiencyandthereforetohighpowerconsumption.Analternativetotheexpenseofawide-dynamic-rangePAistheuseofdeliberateclippingtodigitallydistortthesignalsothatthesignalqualityisstillmaintainedatasufficientlevel.Asanextraadvantage,thedecreasedCFgivesrisetothepossibilityofutilizingthedynamicrangeofthedigitalcircuitryanddigital-to-analogconverterefficiently.Thisthesisdiscussesdigitalmodulatordesign,concentratingonCFreductionalgorithms. | en |
| dc.format.extent | 1308993 bytes | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | http://hdl.handle.net/10266/606 | |
| dc.language.iso | en | en |
| dc.subject | Crest factor, FPGA | en |
| dc.subject | Wireless Base station | en |
| dc.title | Crest Factor Reduction in Digital Front End Hardware for wireless Base Station Transmitter | en |