lte在非授权频段与wi-fi共存技术的研究

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1、万方数据西南交通大学硕士研究生学位论文第1

2、页AbstractWiththecontinuousdevelopmentofwirelesscommunication，spectrumresourcescarcityisgettingmoreandmoreattention．Howtodealwiththegrowingdatatrafficincellularnetworksisahottopictoday．TodeployLTEinunlicensedbandscangetamoreefficientuseofresources，increasethe

3、systemcapacity,andprovideanewwaytosolvethetrafficproblem．Inthisthesis．thecoexistenceperformanceofWLANandLTEinunlicensedbandiSdiscussed．Firstly,thecommonWLANsysteminunlicensedbandisintroduced，andtheprincipleofthecarriersensingandcollisionavoidanceisreviewed．Becauseofthecompetition

4、mechanism，WLANsystemgetslowspectrumutilization，andiseasilyinterfered．ThenitisshownthatdeployingLTEmaycauseaseriousinfluenceontheunlicensedbands．Inordertosolvetheproblem，wediscussthetechniquesandmethodsusedforreducinginterferenceinheterogeneousnetworks．ThecoexistenceofWLANandLYEiS

5、modeledandsimulated，theperformanceofeachsystemisobservedrespectively．WhilethechannelenergydetectedbyWLANdeviceishigherthanthethresholdduringtheLTEtransmissionperiod，theWLANsystemhastobeinthelistenmode．anddoesnottotransmitdata．ThethroughputofWLANdecreasesrapidly．Inordertosolvethis

6、coexistenceproblem，wereviewtheelCICtechnologyusedinLTEnetworkfirst，andthenstudythetechnicalschemeofalmostblanksubframebasedonthetimedomaineICIC，Wealsoproposedanimprovedalgorithmusingblanksubframetechnologyinunlicensedbands．ItreducestheinterferenceofWLANsystembysettingdifferentnum

7、berofblanksubframesduringLTEtransmission．Finallywesimulatethecoexistencesystem，andfindthatusingABStechnologycanreducetheimpactonthecoexistencesystem．Thenwefindthatusinglow—powersubframer—ABStechnologyinunlicensedbandsatLTEdownlinktransmissioncanreducetheinterference．Webuildthesys

8、temmodel，usethesemi．dynamicsimulation，andvalidatetheimprovedcoexistencesystem’Sperformance．Finallywestudythefractionalpowercontrolschemefortheuplinkofthecellularnetwork，proposeanimproveduplinkpowercontrolmethodtoreducetheinterferenceinunlicensedbandsconsideringtheunlicensedbandin

9、terferencecharacteristics．Keywords：Unlic