Radio base station, user terminal and radio communication method

The radio base station according to claim I, further comprising:

• a macrocell carrier frequency extracting section that extracts a carrier frequency of the wide-area cell from the wide-area radio signal;
• and
• a macrocell sampling frequency extracting section that extracts a sampling frequency of a baseband signal of the wide-area cell from the wide-area radio signal,
• wherein the carrier frequency synthesizer generates a carrier frequency of the narrow-area cell, using an extracted carrier frequency of the wide-area cell, and
• the sampling frequency synthesizer generates a sampling frequency of a baseband signal of the narrow-area cell, using an extracted sampling frequency of a baseband signal of the wide-area cell.

A user terminal that communicates with a radio base station for forming a narrow-area cell and a radio base station for forming a wide-area cell in a radio communication system where the narrow-area cell is provided inside the wide-area cell, comprising:

• a wide-area cell frequency synchronization section that executes frequency synchronization with the wide-area cell, based on a wide-area radio signal transmitted from the radio base station for forming the wide-area cell;
• a carrier frequency synthesizer that generates a carrier frequency of the narrow-area cell, based on a carrier frequency of the wide-area cell acquired in the wide-area cell frequency synchronization section;
• and
• a sampling frequency synthesizer that generates a sampling frequency of a baseband signal of the narrow-area cell, based on a sampling frequency of a baseband signal of the wide-area cell acquired in the wide-area cell frequency synchronization section.

A radio communication method in which a user terminal communicates with a radio base station for forming a narrow-area cell and a radio base station for forming a wide-area cell in a radio communication system where the narrow-area cell is provided inside the wide-area cell, comprising the steps of:

• in the radio base station for forming the narrow-area cell,
• generating a carrier frequency of the narrow-area cell, based on a wide-area radio signal transmitted from the radio base station for forming the wide-area cell;
• generating a sampling frequency of a baseband signal of the narrow-area cell, based on the wide-area radio signal;
• in the user terminal,
• executing frequency synchronization with the wide-area cell based on the wide-area radio signal;
• generating a carrier frequency of the narrow-area cell, based on a carrier frequency of the wide-area cell acquired by frequency synchronization with the wide-area cell;
• and
• generating a sampling frequency of a baseband signal of the narrow-area cell, based on a sampling frequency of a baseband signal of the wide-area cell acquired by frequency synchronization with the wide-area cell.