随机接入过程.docx

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1、摘自3GPPTS36.300-93010.1.5RandomAccessProcedureTherandomaccessprocedureischaracterizedby:-CommonprocedureforFDDandTDD。-Oneprocedureirrespectiveofcellsize。Therandomaccessprocedureisperformedforthefollowingsixevents:b5E2RGbCAP-InitialaccessfromRRC_IDLE。-RRCConnectionRe

2、-establishmentprocedure。-Handover。-DLdataarrivalduringRRC_CONNECTEDrequiringrandomaccessprocedure。p1EanqFDPw-E.g.whenULsynchronisationstatusis“non-synchronised”。DXDiTa9E3d-ULdataarrivalduringRRC_CONNECTEDrequiringrandomaccessprocedure。RTCrpUDGiT-E.g.whenULsynchroni

3、sationstatusis"non-synchronised"ortherearenoPUCCHresourcesforSRavailable.5PCzVD7HxA-ForpositioningpurposeduringRRC_CONNECTEDrequiringrandomaccessprocedure。jLBHrnAILg-E.g.whentimingadvanceisneededforUEpositioning。xHAQX74J0XFurthermore,therandomaccessproceduretakestw

4、odistinctforms:LDAYtRyKfE-Contentionbased(applicabletofirstfiveevents>。Zzz6ZB2Ltk-Non-contentionbased(applicabletoonlyhandover,DLdataarrivalandpositioning>.dvzfvkwMI1NormalDL/ULtransmissioncantakeplaceaftertherandomaccessprocedure.rqyn14ZNXI10.1.5.1Contentionbasedr

5、andomaccessprocedureThecontentionbasedrandomaccessprocedureisoutlinedonFigure10.1.5.1-1below:EmxvxOtOco5/5Figure10.1.5.1-1:ContentionbasedRandomAccessProcedureSixE2yXPq5Thefourstepsofthecontentionbasedrandomaccessproceduresare:6ewMyirQFL1>RandomAccessPreambleonRACH

6、inuplink:-Therearetwopossiblegroupsdefinedandoneisoptional.Ifbothgroupsareconfiguredthesizeofmessage3andthepathlossareusedtodeterminewhichgroupapreambleisselectedfrom.Thegrouptowhichapreamblebelongsprovidesanindicationofthesizeofthemessage3andtheradioconditionsatth

7、eUE.Thepreamblegroupinformationalongwiththenecessarythresholdsarebroadcastonsysteminformation.kavU42VRUs2>RandomAccessResponsegeneratedbyMAConDL-SCH:y6v3ALoS89-Semi-synchronous(withinaflexiblewindowofwhichthesizeisoneormoreTTI>withmessage1。M2ub6vSTnP-NoHARQ。-Addres

8、sedtoRA-RNTIonPDCCH。-ConveysatleastRA-preambleidentifier,TimingAlignmentinformation,initialULgrantandassignmentofTemporaryC-RNTI(whichmayormaynot