Base station apparatus, mobile communication system and cell selection communication method

A mobile communication system comprising:

• a plurality of base station apparatuses each including a basic antenna forming a cell;
• and
• a boundary antenna apparatus including a boundary antenna to cover a propagation area in a vicinity of a neighboring-cell boundary between different base station apparatuses, wherein
• each of the plurality of the base station apparatuses includes a switching unit configured to switch an antenna, for transmitting a radio signal to a terminal device existing within the cell of the base station apparatus itself and existing in the propagation area of the boundary antenna, between the basic antenna and the boundary antenna.

A terminal device comprising:

• a first estimating unit configured to estimate a first propagation state from a basic antenna based on a pilot signal transmitted from the basic antenna forming a first cell;
• a second estimating unit configured to estimate a second propagation state from a boundary antenna based on a pilot signal transmitted from the boundary antenna covering a propagation area in the vicinity of a cell boundary between the first cell and a second cell neighboring to the first cell;
• and
• a determining unit configured to determine application of a switching control between the boundary antenna and the basic antenna.