In order to improve the selection of search space candidates for a downlink control channel, an apparatus determines a set of decoding candidates of a lower aggregation level for a downlink control channel based on a random selection from a plurality of potential decoding candidates, wherein the plurality of potential decoding candidates are defined from a second set of decoding candidates of a higher aggregation level. The apparatus then attempts to decode the downlink control channel based on determined sets of decoding candidates of different aggregation levels. The downlink control channel may comprise a PDCCH.