Mobile terminal apparatus, base station apparatus and communication control method

A base station apparatus comprising:

• a transmission section configured to transmit radio frames of a lower cell including a protected subframe being a subframe transmission from a higher cell is inhibited and a non-protected subframe being a subframe transmission from the higher cell is not inhibited;
• a CSI-RS allocation section configured to multiplex a CSI-RS, which is one of reference signals, on the protected subframe or on the non-protected subframe, in a predetermined cycle;
• a CRS allocation section configured to multiplex a CRS, which is one of the reference signals, on each subframe constituting the radio frame of the lower cell;
• a receiving section configured to receive two types of reception quality information, including the reception quality of the protected subframe that is fed back from a mobile terminal apparatus having received the radio frames in the lower cell, and a difference value between the reception quality of the protected subframe and the reception quality of the non-protected subframe;
• and
• a user data allocation section configured to allocate radio resources to the mobile terminal apparatus using the two types of the reception quality information fed back from the mobile terminal apparatus.

A CSI feedback method comprising the steps of:

• receiving radio frames of a lower cell including a protected subframe being a subframe transmission from a higher cell is inhibited and a non-protected subframe being a subframe transmission from the higher cell is not inhibited;
• measuring reception quality from reference signals multiplexed individually on the protected subframe and the non-protected subframe;
• calculating a difference value between the reception quality of the protected subframe and the reception quality of the non-protected subframe;
• and
• notifying measured reception quality information of the protected subframe, and the calculated difference value, to a base station apparatus.

A communication control method comprising the steps of:

• transmitting radio frames of a lower cell including a protected subframe being a subframe transmission from a higher cell is inhibited and a non-protected subframe being a subframe transmission from the higher cell is not inhibited;
• multiplexing a CSI-RS, which is one of reference signals, on the protected subframe or on the non-protected subframe, in a predetermined cycle;
• multiplexing a CRS, which is one of the reference signals, on each subframe constituting the radio frame of the lower cell;
• receiving two types of reception quality information, including the reception quality of the protected subframe that is fed back from a mobile terminal apparatus having received the radio frames in the lower cell, and a difference value between the reception quality of the protected subframe and the reception quality of the non-protected subframe;
• and
• allocating radio resources to the mobile terminal apparatus using the two types of the reception quality information fed back from the mobile terminal apparatus.