Radio base station apparatus and transmission power control method

A transmission power control method in a heterogeneous network including a macro cell and a femto cell, the transmission power control method comprising the steps of:

• in a radio base station apparatus of the macro cell:
• receiving registration information as to whether or not a mobile terminal apparatus is a non-member mobile terminal apparatus, which is not a mobile terminal apparatus having registered access to a radio base station apparatus of the femto cell, a received quality measurement result, and cell information;
• determining whether or not the non-member mobile terminal apparatus has come near the femto cell from the registration information, the received quality measurement result, and the cell information;
• and
• reporting neighbor information, which indicates that the non-member mobile terminal apparatus has come near the femto cell, to the radio base station apparatus of the femto cell, by a backhaul link;
• and
• in the radio base station apparatus of the femto cell:
• generating a transmission signal;
• and
• reducing transmission power of the transmission signal based on the neighbor information.