Radio communication system, base station, and control method thereof

A second base station in a radio communication system, wherein a radio frame of the radio communication system includes plural subframes, each subframe is formed by two consecutive time slots, each subframe includes plural resource blocks in frequency domain, and each resource block is formed by plural subcarriers, the second base station comprising:

• a transmitter that transmits information on resource block use rate in the second base station to a first base station, when a cell coverage of a second base station is extended and the first base station sets a subframe arrangement formed by at least one first subframe and at least one second subframe in which transmission power of the first base station is limited to low compared with the at least one first subframe,
• wherein the information on resource block use rate is used for modifying the subframe arrangement.

A control method for a first base station in a radio communication system, wherein a radio frame of the radio communication system includes plural subframes, each subframe is formed by two consecutive time slots, each subframe includes plural resource blocks in frequency domain, and each resource block is formed by plural subcarriers, the control method comprising:

• determining a subframe arrangement formed by at least one first subframe and at least one second subframe in which transmission power of the first base station is limited to low compared with the at least one first subframe, and setting the subframe arrangement to the first base station, when a cell coverage of a second base station is extended;
• receiving information on resource block use rate in the second base station, from the second base station;
• modifying the subframe arrangement at least based on the information on resource block use rate.

A control method for a second base station in a radio communication system, wherein a radio frame of the radio communication system includes plural subframes, each subframe is formed by two consecutive time slots, each subframe includes plural resource blocks in frequency domain, and each resource block is formed by plural subcarriers, the control method comprising:

• transmitting information on resource block use rate in the second base station to a first base station, when a cell coverage of a second base station is extended and the first base station sets a subframe arrangement formed by at least one first subframe and at least one second subframe in which transmission power of the first base station is limited to low compared with the at least one first subframe,
• wherein the information on resource block use rate is used for modifying the subframe arrangement.