Disclosed is a mobile communications system including a plurality of base station apparatuses which are located at geographically dispersed locations and perform a wireless communication with a mobile device. The system further includes a maximum ratio combining unit which performs maximum ratio combining processing regarding a signal the base station apparatuses receive from the mobile device, and a selection combining unit which performs selection combining processing regarding the signal from the mobile device. A selection unit included in the system selects one or both of the maximum ratio combining unit and the selection combining unit according to at least one of an external factor and a change of a distribution state of the mobile device under communication.