A communication apparatus includes circuitry and a transmitter. The circuitry maps a precoded downlink control signal to one of a plurality of mapping candidates. The precoded downlink control signal is prepared using a first precoding for single-antenna port transmission with a single antenna port in localized allocation mode. The precoded downlink control signal is prepared using a second precoding for multi-antenna ports transmission with two antenna ports in distributed allocation mode. The plurality of mapping candidates is comprised of a plurality of aggregation levels, and one or more of the aggregation levels that is higher than a boundary among the plurality of aggregation levels is associated with only the multi-antenna ports transmission, the boundary being determined based on signaling indicated from the base station apparatus. The transmitter transmits the precoded downlink control signal.