US Patent 9491749 Radio communication method, radio communication system and radio base station

To appropriately allocate radio resources to downlink control information, in the enhanced downlink control channel, a radio communication method in which a radio base station transmits downlink control information to each user terminal via an enhanced downlink control channel frequency division multiplexed with a downlink shared data channel is provided. The method includes generating the downlink control information in eCCE unit, the eCCE being made up with a plurality of eREGs, and mapping the downlink control information in eREG unit to a plurality of resource regions for the enhanced downlink control channel. Each eREG is made up with a plurality of REs, and the radio base station performs mapping to each of the resource regions in such a manner that the enhanced resource element groups (eREGs) are uniform in number of resource elements. The REs that make up 1 eREG are distributed to a plurality of OFDM symbols.