A base station apparatus for use in a radio communication system in which a time resource used for downlink from the base station apparatus to a relay station apparatus and a time resource used for downlink from the relay station apparatus to a mobile station apparatus covered by the relay station apparatus are time-divided within a predetermined period, the base station apparatus comprising: a mapping section adapted to map a physical downlink control channel for the mobile station apparatus to first one or more symbols from the beginning of the predetermined period and to map a control signal for the relay station apparatus to a symbol in the predetermined period; and a transmission section adapted to transmit the mapped physical downlink control channel and the mapped control signal for the relay station apparatus, wherein the symbol, to which the mapping section is adapted to map the control signal for the relay station apparatus, is a (D+1)-th symbol in the predetermined period, wherein D denotes a maximum number of symbols, to which the physical downlink control channel for the mobile station apparatus is mapped; and wherein: the radio communication system supports a long term evolution system, the predetermined period is a sub-frame length, the mapping section is adapted to calculate a range of symbols within a sub-frame that can be received by the relay station apparatus, on the basis of difference of frame timing of the sub-frame between the base station apparatus and the relay station apparatus and on the basis of a propagation delay time between the base station apparatus and the relay station apparatus, and map a data signal for the relay station apparatus in any one of the symbols in the range of symbols that can be received by the relay station apparatus. a mapping section adapted to map a physical downlink control channel for the mobile station apparatus to first one or more symbols from the beginning of the predetermined period and to map a control signal for the relay station apparatus to a symbol in the predetermined period; and a transmission section adapted to transmit the mapped physical downlink control channel and the mapped control signal for the relay station apparatus, wherein the symbol, to which the mapping section is adapted to map the control signal for the relay station apparatus, is a (D+1)-th symbol in the predetermined period, wherein D denotes a maximum number of symbols, to which the physical downlink control channel for the mobile station apparatus is mapped; and wherein: the radio communication system supports a long term evolution system, the predetermined period is a sub-frame length, the mapping section is adapted to calculate a range of symbols within a sub-frame that can be received by the relay station apparatus, on the basis of difference of frame timing of the sub-frame between the base station apparatus and the relay station apparatus and on the basis of a propagation delay time between the base station apparatus and the relay station apparatus, and map a data signal for the relay station apparatus in any one of the symbols in the range of symbols that can be received by the relay station apparatus. <EOS>