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

A radio communication system comprising a first radio base station apparatus and a second radio base station apparatus that is configured to be able to communicate with the first radio base station apparatus, wherein:

• the first radio base station apparatus comprises:
• a first communication quality measurement section that measures received quality of an uplink reference signal transmitted from a user terminal, and generates first received quality information;
• and
• a reporting section that reports the first communication quality information to the second radio base station apparatus;
• and
• the second radio base station apparatus comprises:
• a second communication quality measurement section that measures received quality of the uplink reference signal transmitted from the user terminal, and generates second communication quality information;
• a correction value determining section that determines a correction value for transmission power of the user terminal on an uplink based on the first communication quality information and the second communication quality information;
• and
• a reporting section that reports the determined correction value to the user terminal;
• and
• the reporting section reports the correction value to the user terminal using a transmission power control command field of three bits or more, provided in a downlink control signal.

A radio communication system comprising a first radio base station apparatus and a second radio base station apparatus that is configured to be able to communicate with the first radio base station apparatus, wherein:

• the first radio base station apparatus comprises:
• a first communication quality measurement section that measures received quality of an uplink reference signal transmitted from a user terminal, and generates first received quality information;
• a reporting section that reports the first communication quality information to the second radio base station apparatus;
• and
• a transmission section that transmits a first reference signal for channel quality measurement to the user terminal;
• and
• the second radio base station apparatus comprises:
• a second communication quality measurement section that measures received quality of the uplink reference signal transmitted from the user terminal, and generates second received quality information;
• a determining section that determines a radio base station apparatus which the user terminal connects with on an uplink based on the first communication quality information and the second communication quality information;
• and
• a transmission section that transmits a second reference signal for channel quality measurement to the user terminal;
• and
• the user terminal determines path loss based on the first reference signal or the second reference signal transmitted from the radio base station apparatus connected on the uplink, and sets transmission power on the uplink based on the path loss.

A radio communication method comprising:

• a step in which a user terminal transmits an uplink reference signal to a first radio base station apparatus and a second radio base station apparatus;
• a step in which the first radio base station apparatus measures received quality of the uplink reference signal and generates first communication quality information;
• a step in which the second radio base station apparatus measures received quality of the uplink reference signal and generates second communication quality information;
• a step in which the first radio base station apparatus reports the first communication quality information to the second radio base station apparatus;
• a step in which the second radio base station apparatus determines a correction value for transmission power of the user terminal on an uplink based on the first communication quality information and the second communication quality information;
• a step in which the determined correction value is reported to the user terminal;
• and
• a step in which the user terminal sets the transmission power on the uplink based on the correction value.

A radio communication method comprising:

• a step in which a user terminal transmits an uplink reference signal to a first radio base station apparatus and a second radio base station apparatus;
• a step in which the first radio base station apparatus measures received quality of the uplink reference signal and generates first communication quality information;
• a step in which the second radio base station apparatus measures received quality of the uplink reference signal and generates second communication quality information;
• a step in which the first radio base station apparatus reports the first communication quality information to the second radio base station apparatus;
• a step in which the second radio base station apparatus determines a correction value for transmission power of the user terminal on an uplink based on the first communication quality information and the second communication quality information;
• a step in which the determined correction value is reported to the user terminal using a transmission power control command field of three bits or more, provided in a downlink control signal;
• and
• a step in which the user terminal sets the transmission power on the uplink based on the correction value.

A radio communication method comprising:

• a step in which a user terminal transmits an uplink reference signal to a first radio base station apparatus and a second radio base station apparatus;
• a step in which the first radio base station apparatus measures received quality of the uplink reference signal and generates first communication quality information;
• a step in which the second radio base station apparatus measures received quality of the uplink reference signal and generates second communication quality information;
• a step in which the first radio base station apparatus reports the first communication quality information to the second radio base station apparatus;
• a step in which the second radio base station apparatus determines a radio base station apparatus which the user terminal connects with on an uplink based on the first communication quality information and the second communication quality information;
• a step in which the first radio base station apparatus transmits a first reference signal for channel quality measurement to the user terminal;
• a step in which the second radio base station apparatus transmits a second reference signal for channel quality measurement to the user terminal;
• a step in which the user terminal determines path loss based on the first reference signal or the second reference signal transmitted from the radio base station apparatus to connect with on the uplink;
• and
• a step in which the transmission power on the uplink is set based on the path loss.

A radio communication method to use a first radio base station apparatus, a second radio base station apparatus that is configured to be able to communicate with the first radio base station apparatus, and a user terminal that performs radio communication with the first radio base station apparatus and the second radio base station apparatus, the radio communication method comprising:

• a step in which the first radio base station apparatus receives a reference signal or a data signal and report information regarding use of power, from the user terminal, and calculates a correction value based on these;
• a step in which the correction value is reported to the second radio base station apparatus;
• and
• a step in which the second radio base station apparatus reports the correction value reported from the first radio base station apparatus, to the user terminal.

A radio base station apparatus that is configured to be able to communicate with another radio base station apparatus, comprising:

• a communication quality measurement section that measures received quality of an uplink reference signal transmitted from a user terminal, and generates communication quality information;
• a receiving section that receives communication quality information that is generated in the other radio base station apparatus by measuring received quality of the uplink reference signal transmitted from the user terminal;
• a correction value determining section that determines a correction value for transmission power of the user terminal on an uplink based on the communication quality information, and the communication quality information by the other radio base station apparatus;
• and
• a reporting section that reports the determined correction value to the user terminal.

A radio base station apparatus that is configured to be able to communicate with another radio base station apparatus, comprising:

• a receiving section that receives an uplink reference signal, a data signal and report information regarding use of power, transmitted from a user terminal;
• a measurement section that measures received power of the uplink reference signal or the data signal;
• and
• a reporting section that calculates a correction value for transmission power of the user terminal on an uplink based on the received power and the report information regarding use of power, and reports the correction value to the other radio base station apparatus.

A user terminal comprising:

• a transmission section that transmits an uplink reference signal to a first radio base station apparatus and a second radio base station apparatus that are configured to be able to communicate with each other;
• a receiving section that receives a correction value for transmission power on an uplink, determined by the first radio base station apparatus or the second radio base station apparatus based on received quality of the uplink reference signal at each radio base station apparatus;
• and
• a setting section that sets the transmission power on the uplink based on the correction value.

A user terminal comprising:

• a transmission section that transmits an uplink reference signal, a data signal, and report information regarding use of power, to a first radio base station apparatus;
• a receiving section that receives, from a second radio base station apparatus that is configured to able to communicate with the first radio base station apparatus, a correction value for transmission power on an uplink, calculated in the first radio base station apparatus based on received power of the uplink reference signal or the data signal, and the report information regarding use of power;
• and
• a setting section that sets the transmission power on the uplink based on the correction value.