Methods for allocating a physical downlink control channel (PDCCH) to reduce a number of PDCCH candidates in a search space for carrier aggregation on a user equipment (UE) are disclosed. The method comprises the step of selecting a control channel element (CCE) aggregation level for a PDCCH allocation for each of a plurality of user equipments (UEs) at an evolved NodeB (eNB). The operation of identifying a transmission mode for each of a plurality of component carriers (CCs) associated with the PDCCH at the eNB follows. The next operation of the method is assigning each CC's downlink control information (DCI) into CCEs in a PDCCH search space in the PDCCH starting at a CCE location based on the CC's transmission mode and the CCE aggregation level for the UE receiving the CC.