Radio communication system and user device

A radio communication system comprising:

• base stations;
• and
• user devices,
• each base station including:
• a downlink transmission power determiner configured to determine, based on parameters associated with locations of user devices connected to the base station, downlink transmission power for downlink transmission to each of the user devices connected to the base station;
• a radio signal transmitter configured to transmit a radio signal in which a plurality of non-orthogonal signals are mixed, each of the plurality of non-orthogonal signals being transmitted with the corresponding downlink transmission power determined by the downlink transmission power determiner, each of the plurality of non-orthogonal signals being directed to a corresponding one of the user devices connected to the base station;
• and
• an information notifier configured to notify each of the user devices connected to the base station of information associated with at least one of a location of the user device and the downlink transmission power for the user device,
• each user device including:
• a radio signal receiver configured to receive, from a desired base station to which the user device is connected, a radio signal including the plurality of non-orthogonal signals;
• an interference rejection combining processor configured to suppress an interference signal component received from an interfering base station to which the user device is not connected, the interference signal component being in one of the plurality of non-orthogonal signals in the radio signal received by the radio signal receiver;
• a demodulator configured to demodulate the one of the plurality of non-orthogonal signals in which the interference signal component has been suppressed by the interference rejection combining processor;
• a location recognizer configured to recognize, based on the information transmitted from the desired base station, a parameter associated with the location of the user device;
• and
• a non-orthogonal signal canceller configured to, when the location recognizer recognizes that the user device is located within a cell area of the desired base station and is not located nearest to a boundary of the cell area, cancel, from the radio signal, the one of the plurality of non-orthogonal signals demodulated by the demodulator,
• wherein:
• when the location recognizer recognizes that the user device is located within the cell area of the desired base station and is located nearest to the boundary of the cell area, the demodulator demodulates, as a signal directed to the user device, the radio signal in which the interference signal component has been suppressed by the interference rejection combining processor, and the non-orthogonal signal canceller does not operate;
• and
• when the location recognizer recognizes that the user device is located within the cell area of the desired base station and is not located nearest to the boundary of the cell area, until the demodulator demodulates the signal directed to the user device, the interference rejection combining processor suppresses an interference signal component in the one of the plurality of non-orthogonal signals outputted from the non-orthogonal signal canceller and the demodulator demodulates the one of the plurality of non-orthogonal signals in which the interference signal component has been suppressed by the interference rejection combining processor.