Radio communication system, feedback method, user terminal, and radio base station apparatus

A radio communication system comprising a plurality of radio base station apparatuses and a user terminal that is configured to be able to communicate with the plurality of radio base station apparatuses, wherein:

• the radio base station apparatuses comprise:
• a transmission section configured to transmit a reference signal for channel state measurement to the user terminal;
• and
• a receiving section configured to receive channel state information generated in the user terminal based on the reference signal;
• and
• the user terminal comprises:
• a channel state information generating section configured to be able to generate a plurality of pieces of channel state information, including channel state information that is represented by a ratio of a received signal component from a serving cell and a received signal component from a coordinated cell, when the plurality of radio base station apparatuses coordinate and perform transmission;
• and
• a transmission section configured to transmit the plurality of pieces of channel state information to the radio base station apparatus.

A method of feeding back channel state information from a user terminal when a plurality of radio base station apparatuses coordinate and perform transmission, the method comprising the steps in which:

• a radio base station apparatus transmits a reference signal for channel state measurement to the user terminal;
• the user terminal generates a plurality of pieces of channel state information, including channel state information from which interference from a coordinated cell is cancelled, based on the reference signal transmitted from the radio base station apparatus;
• and
• the user terminal transmits the plurality of pieces of channel state information to the radio base station apparatus.

A user terminal which is configured to be able to communicate with a plurality of radio base station apparatuses, the user terminal comprising:

• a receiving section configured to receive a reference signal for channel state measurement from a radio base station apparatus;
• a channel state information generating section configured to be able to generate a plurality of pieces of channel state information, including channel state information from which interference from a coordinated cell is cancelled, based on the reference signal, when the plurality of radio base station apparatuses coordinate and perform transmission;
• and
• a transmission section configured to transmit the plurality of pieces of channel state information to the radio base station apparatus.