A reference signal mapping method comprising: mapping a first reference signal, for use by both a first radio communication terminal apparatus configured to communicate with not more than N antennas of a radio communication base station apparatus and a second radio communication terminal apparatus configured to communicate with more than N antennas of the radio communication base station apparatus, to all resource blocks in one frame; and mapping, for each subframe in the one frame, a second reference signal, for use only by the second radio communication terminal apparatus, to a plurality of resource blocks; characterized in that all the resource blocks in the subframe are grouped into a plurality of resource block groups, wherein each resource block group is comprised of the same number of resource blocks; the method further comprises allocating the first radio communication terminal apparatus and the second radio communication terminal apparatus to resource blocks in units of the resource block groups; the second reference signal is mapped to the plurality of resource blocks in the units of the resource block groups used for the allocation, so that a part of the plurality of resource block groups in each subframe is comprised of the plurality of resource blocks, to which the second reference signal is mapped; the first radio communication terminal apparatus is not allocated to the part of the resource blocks groups, which comprise the plurality of resource blocks, to which the second reference signal is mapped; and the first reference signal and the second reference signal are cell-specific reference signals. mapping a first reference signal, for use by both a first radio communication terminal apparatus configured to communicate with not more than N antennas of a radio communication base station apparatus and a second radio communication terminal apparatus configured to communicate with more than N antennas of the radio communication base station apparatus, to all resource blocks in one frame; and mapping, for each subframe in the one frame, a second reference signal, for use only by the second radio communication terminal apparatus, to a plurality of resource blocks; characterized in that all the resource blocks in the subframe are grouped into a plurality of resource block groups, wherein each resource block group is comprised of the same number of resource blocks; the method further comprises allocating the first radio communication terminal apparatus and the second radio communication terminal apparatus to resource blocks in units of the resource block groups; the second reference signal is mapped to the plurality of resource blocks in the units of the resource block groups used for the allocation, so that a part of the plurality of resource block groups in each subframe is comprised of the plurality of resource blocks, to which the second reference signal is mapped; the first radio communication terminal apparatus is not allocated to the part of the resource blocks groups, which comprise the plurality of resource blocks, to which the second reference signal is mapped; and the first reference signal and the second reference signal are cell-specific reference signals. <EOS>