Patent ID: 8027297

Claim:
A method of transmitting a downlink control signal by a base station, the method comprising: determining a transmission format among multiple transmission formats for the downlink control signal including scheduling information for a downlink data transmission, wherein a smallest time-frequency resource element is defined by one subcarrier in a frequency domain and one orthogonal frequency division multiplexing (OFDM) symbol in a time domain, wherein each of the multiple transmission formats is defined such that the downlink control signal is transmitted by a unit whose size corresponds to a multiplication of an integer value, differently determined for each of the multiple transmission formats, by a predetermined frequency domain size unit for transmitting the downlink control signal, wherein the predetermined frequency domain size unit used for transmitting the downlink control signal is predetermined to comprise a plurality of the smallest time-frequency resource elements arranged in the frequency domain at one OFDM symbol; transmitting the downlink control signal in accordance with the determined transmission format to each of a plurality of user equipment; and transmitting downlink data to each of the plurality of user equipment according to the scheduling information of the downlink control signal.