User terminal, radio base station and radio communication method

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

• a processor and a memory, wherein
• the processor generates a sampling frequency of a baseband signal of the wide-area cell as a reference signal;
• converts a frequency of the reference signal by n/m times, where n is the length of a subframe of the wide-area cell and m is the length of a subframe of the narrow-area cell when the narrow-area cell applies FDD;
• and
• uses a frequency subjected to frequency conversion as a sampling frequency of a baseband signal of the narrow-area cell,
• wherein the processor is configured to
• set a radio frame length of the narrow-area cell to the same length as the subframe length of the wide-area cell,
• wherein n/m is greater than 1,
• wherein the processor sets a subframe length of the narrow-area cell at the subframe length of the wide-area cell/(n/m) when the narrow-area cell applies FDD, while when the narrow-area cell applies TDD, setting a subframe length of the narrow-cell at two times the subframe length in applying FDD to perform assignment of a signal.

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

• in the user terminal, generating a sampling frequency of a baseband signal of the wide-area cell as a reference signal;
• converting a frequency of the reference signal by n/m times, where n is the length of a subframe of the wide-area cell and m is the length of a subframe of the narrow-area cell when the narrow-area cell applies FDD;
• and
• using a frequency subjected to frequency conversion as a sampling frequency of a baseband signal of the narrow-area cell,
• wherein the user terminal
• sets a radio frame length of the narrow-area cell to the same length as the subframe length of the wide-area cell,
• wherein n/m is greater than 1,
• wherein the user terminal sets a subframe length of the narrow-area cell at the subframe length of the wide-area cell/(n/m) when the narrow-area cell applies FDD, while when the narrow-area cell applies TDD, setting a subframe length of the narrow-cell at two times the subframe length in applying FDD to perform assignment of a signal.