Orthogonalfrequencypisionmultipleaccess(OFDMA)isapopularandwidelyacceptedmultipleaccesstechniquetoprovidehighdatarateservicesinamobileenvironmentintheareaofwirelesscommunications.OFDMAcanprovidebetterflexibilityinallocatingtheradiospectrabyutilizingsubcarrierallocations,scheduling,andenergycontroltoobtainmulti-dimensionpersitygains.Duetoitsresourceallocationflexibility,OFDMAhasbeenwidelyusedasagreenairinterfacetechnologyfortheemergingbroadbandwirelessaccessnetworks.ThispaperextensivelyaddressestheintegrationofgreenOFDMAtothefutureairinterfacetechnologies,forinstance:two-tiercellular,multiradioaccesstechnologies(RATs),FemtoCell,andrelaynetworks.ThemainfocusofthepaperistoreviewandanalyzethecurrentOFDMAtechniquestoaddressthegreenresourceallocationinmultiuserpersity,wherethecriticalconstraintsarethecomputationalcomplexity,energyefficiency,andthesub-channelassignment.ThefuturetrendofOFDMAbasednetworkswillaimtomaximizetheenergyefficiencyoftheexclusivechannelassignmentthroughajointsub-channelandpowerallocationtoaccommodatehighdatatrafficnetworksspeciallytherelaybased5Gcellularnetworks.
