Technology 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) is disclosed. The UE is configured with a carrier information field (CIF) having a communications processor to determine physical downlink control channel (PDCCH) assignments of a cellular communication system. The communication processor can monitor in a cell a set of PDCCH candidates defined in a search space Sk(L) at an aggregation level Lε{1,2,4,8} for a subframe (k) which includes a set of control channel elements (CCEs) and to decode a PDCCH of the set of PDCCH candidates according to downlink control information (DCI).