1Foreword 3GPPIMS(IPMultimediaSubsystem)isthenextgenerationnetworkfordeliveringIPmultimedia services.IMSisstandardizedbythe3rdGenerationPartnershipProject(3GPP).IMSservicescould beusedoveranytypeofnetwork,suchas3GPPLTE,GPRS,WirelessLAN,CDMA2000orfixed line.